12874c5fdSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * Routines having to do with the 'struct sk_buff' memory handlers. 41da177e4SLinus Torvalds * 5113aa838SAlan Cox * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> 61da177e4SLinus Torvalds * Florian La Roche <rzsfl@rz.uni-sb.de> 71da177e4SLinus Torvalds * 81da177e4SLinus Torvalds * Fixes: 91da177e4SLinus Torvalds * Alan Cox : Fixed the worst of the load 101da177e4SLinus Torvalds * balancer bugs. 111da177e4SLinus Torvalds * Dave Platt : Interrupt stacking fix. 121da177e4SLinus Torvalds * Richard Kooijman : Timestamp fixes. 131da177e4SLinus Torvalds * Alan Cox : Changed buffer format. 141da177e4SLinus Torvalds * Alan Cox : destructor hook for AF_UNIX etc. 151da177e4SLinus Torvalds * Linus Torvalds : Better skb_clone. 161da177e4SLinus Torvalds * Alan Cox : Added skb_copy. 171da177e4SLinus Torvalds * Alan Cox : Added all the changed routines Linus 181da177e4SLinus Torvalds * only put in the headers 191da177e4SLinus Torvalds * Ray VanTassle : Fixed --skb->lock in free 201da177e4SLinus Torvalds * Alan Cox : skb_copy copy arp field 211da177e4SLinus Torvalds * Andi Kleen : slabified it. 221da177e4SLinus Torvalds * Robert Olsson : Removed skb_head_pool 231da177e4SLinus Torvalds * 241da177e4SLinus Torvalds * NOTE: 251da177e4SLinus Torvalds * The __skb_ routines should be called with interrupts 261da177e4SLinus Torvalds * disabled, or you better be *real* sure that the operation is atomic 271da177e4SLinus Torvalds * with respect to whatever list is being frobbed (e.g. via lock_sock() 281da177e4SLinus Torvalds * or via disabling bottom half handlers, etc). 291da177e4SLinus Torvalds */ 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* 321da177e4SLinus Torvalds * The functions in this file will not compile correctly with gcc 2.4.x 331da177e4SLinus Torvalds */ 341da177e4SLinus Torvalds 35e005d193SJoe Perches #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 36e005d193SJoe Perches 371da177e4SLinus Torvalds #include <linux/module.h> 381da177e4SLinus Torvalds #include <linux/types.h> 391da177e4SLinus Torvalds #include <linux/kernel.h> 401da177e4SLinus Torvalds #include <linux/mm.h> 411da177e4SLinus Torvalds #include <linux/interrupt.h> 421da177e4SLinus Torvalds #include <linux/in.h> 431da177e4SLinus Torvalds #include <linux/inet.h> 441da177e4SLinus Torvalds #include <linux/slab.h> 45de960aa9SFlorian Westphal #include <linux/tcp.h> 46de960aa9SFlorian Westphal #include <linux/udp.h> 4790017accSMarcelo Ricardo Leitner #include <linux/sctp.h> 481da177e4SLinus Torvalds #include <linux/netdevice.h> 491da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 501da177e4SLinus Torvalds #include <net/pkt_sched.h> 511da177e4SLinus Torvalds #endif 521da177e4SLinus Torvalds #include <linux/string.h> 531da177e4SLinus Torvalds #include <linux/skbuff.h> 549c55e01cSJens Axboe #include <linux/splice.h> 551da177e4SLinus Torvalds #include <linux/cache.h> 561da177e4SLinus Torvalds #include <linux/rtnetlink.h> 571da177e4SLinus Torvalds #include <linux/init.h> 58716ea3a7SDavid Howells #include <linux/scatterlist.h> 59ac45f602SPatrick Ohly #include <linux/errqueue.h> 60268bb0ceSLinus Torvalds #include <linux/prefetch.h> 610d5501c1SVlad Yasevich #include <linux/if_vlan.h> 622a2ea508SJohn Hurley #include <linux/mpls.h> 631da177e4SLinus Torvalds 641da177e4SLinus Torvalds #include <net/protocol.h> 651da177e4SLinus Torvalds #include <net/dst.h> 661da177e4SLinus Torvalds #include <net/sock.h> 671da177e4SLinus Torvalds #include <net/checksum.h> 68ed1f50c3SPaul Durrant #include <net/ip6_checksum.h> 691da177e4SLinus Torvalds #include <net/xfrm.h> 708822e270SJohn Hurley #include <net/mpls.h> 713ee17bc7SMat Martineau #include <net/mptcp.h> 721da177e4SLinus Torvalds 737c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 74ad8d75ffSSteven Rostedt #include <trace/events/skb.h> 7551c56b00SEric Dumazet #include <linux/highmem.h> 76b245be1fSWillem de Bruijn #include <linux/capability.h> 77b245be1fSWillem de Bruijn #include <linux/user_namespace.h> 782544af03SMatteo Croce #include <linux/indirect_call_wrapper.h> 79a1f8e7f7SAl Viro 807b7ed885SBart Van Assche #include "datagram.h" 817b7ed885SBart Van Assche 8208009a76SAlexey Dobriyan struct kmem_cache *skbuff_head_cache __ro_after_init; 8308009a76SAlexey Dobriyan static struct kmem_cache *skbuff_fclone_cache __ro_after_init; 84df5042f4SFlorian Westphal #ifdef CONFIG_SKB_EXTENSIONS 85df5042f4SFlorian Westphal static struct kmem_cache *skbuff_ext_cache __ro_after_init; 86df5042f4SFlorian Westphal #endif 875f74f82eSHans Westgaard Ry int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS; 885f74f82eSHans Westgaard Ry EXPORT_SYMBOL(sysctl_max_skb_frags); 891da177e4SLinus Torvalds 901da177e4SLinus Torvalds /** 91f05de73bSJean Sacren * skb_panic - private function for out-of-line support 921da177e4SLinus Torvalds * @skb: buffer 931da177e4SLinus Torvalds * @sz: size 94f05de73bSJean Sacren * @addr: address 9599d5851eSJames Hogan * @msg: skb_over_panic or skb_under_panic 961da177e4SLinus Torvalds * 97f05de73bSJean Sacren * Out-of-line support for skb_put() and skb_push(). 98f05de73bSJean Sacren * Called via the wrapper skb_over_panic() or skb_under_panic(). 99f05de73bSJean Sacren * Keep out of line to prevent kernel bloat. 100f05de73bSJean Sacren * __builtin_return_address is not used because it is not always reliable. 1011da177e4SLinus Torvalds */ 102f05de73bSJean Sacren static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr, 10399d5851eSJames Hogan const char msg[]) 1041da177e4SLinus Torvalds { 10541a46913SJesper Dangaard Brouer pr_emerg("%s: text:%px len:%d put:%d head:%px data:%px tail:%#lx end:%#lx dev:%s\n", 10699d5851eSJames Hogan msg, addr, skb->len, sz, skb->head, skb->data, 1074305b541SArnaldo Carvalho de Melo (unsigned long)skb->tail, (unsigned long)skb->end, 10826095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1091da177e4SLinus Torvalds BUG(); 1101da177e4SLinus Torvalds } 1111da177e4SLinus Torvalds 112f05de73bSJean Sacren static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr) 1131da177e4SLinus Torvalds { 114f05de73bSJean Sacren skb_panic(skb, sz, addr, __func__); 1151da177e4SLinus Torvalds } 1161da177e4SLinus Torvalds 117f05de73bSJean Sacren static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr) 118f05de73bSJean Sacren { 119f05de73bSJean Sacren skb_panic(skb, sz, addr, __func__); 120f05de73bSJean Sacren } 121c93bdd0eSMel Gorman 122c93bdd0eSMel Gorman /* 123c93bdd0eSMel Gorman * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells 124c93bdd0eSMel Gorman * the caller if emergency pfmemalloc reserves are being used. If it is and 125c93bdd0eSMel Gorman * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves 126c93bdd0eSMel Gorman * may be used. Otherwise, the packet data may be discarded until enough 127c93bdd0eSMel Gorman * memory is free 128c93bdd0eSMel Gorman */ 129c93bdd0eSMel Gorman #define kmalloc_reserve(size, gfp, node, pfmemalloc) \ 130c93bdd0eSMel Gorman __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc) 13161c5e88aSstephen hemminger 13261c5e88aSstephen hemminger static void *__kmalloc_reserve(size_t size, gfp_t flags, int node, 13361c5e88aSstephen hemminger unsigned long ip, bool *pfmemalloc) 134c93bdd0eSMel Gorman { 135c93bdd0eSMel Gorman void *obj; 136c93bdd0eSMel Gorman bool ret_pfmemalloc = false; 137c93bdd0eSMel Gorman 138c93bdd0eSMel Gorman /* 139c93bdd0eSMel Gorman * Try a regular allocation, when that fails and we're not entitled 140c93bdd0eSMel Gorman * to the reserves, fail. 141c93bdd0eSMel Gorman */ 142c93bdd0eSMel Gorman obj = kmalloc_node_track_caller(size, 143c93bdd0eSMel Gorman flags | __GFP_NOMEMALLOC | __GFP_NOWARN, 144c93bdd0eSMel Gorman node); 145c93bdd0eSMel Gorman if (obj || !(gfp_pfmemalloc_allowed(flags))) 146c93bdd0eSMel Gorman goto out; 147c93bdd0eSMel Gorman 148c93bdd0eSMel Gorman /* Try again but now we are using pfmemalloc reserves */ 149c93bdd0eSMel Gorman ret_pfmemalloc = true; 150c93bdd0eSMel Gorman obj = kmalloc_node_track_caller(size, flags, node); 151c93bdd0eSMel Gorman 152c93bdd0eSMel Gorman out: 153c93bdd0eSMel Gorman if (pfmemalloc) 154c93bdd0eSMel Gorman *pfmemalloc = ret_pfmemalloc; 155c93bdd0eSMel Gorman 156c93bdd0eSMel Gorman return obj; 157c93bdd0eSMel Gorman } 158c93bdd0eSMel Gorman 1591da177e4SLinus Torvalds /* Allocate a new skbuff. We do this ourselves so we can fill in a few 1601da177e4SLinus Torvalds * 'private' fields and also do memory statistics to find all the 1611da177e4SLinus Torvalds * [BEEP] leaks. 1621da177e4SLinus Torvalds * 1631da177e4SLinus Torvalds */ 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds /** 166d179cd12SDavid S. Miller * __alloc_skb - allocate a network buffer 1671da177e4SLinus Torvalds * @size: size to allocate 1681da177e4SLinus Torvalds * @gfp_mask: allocation mask 169c93bdd0eSMel Gorman * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache 170c93bdd0eSMel Gorman * instead of head cache and allocate a cloned (child) skb. 171c93bdd0eSMel Gorman * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for 172c93bdd0eSMel Gorman * allocations in case the data is required for writeback 173b30973f8SChristoph Hellwig * @node: numa node to allocate memory on 1741da177e4SLinus Torvalds * 1751da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and a 17694b6042cSBen Hutchings * tail room of at least size bytes. The object has a reference count 17794b6042cSBen Hutchings * of one. The return is the buffer. On a failure the return is %NULL. 1781da177e4SLinus Torvalds * 1791da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1801da177e4SLinus Torvalds * %GFP_ATOMIC. 1811da177e4SLinus Torvalds */ 182dd0fc66fSAl Viro struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, 183c93bdd0eSMel Gorman int flags, int node) 1841da177e4SLinus Torvalds { 185e18b890bSChristoph Lameter struct kmem_cache *cache; 1864947d3efSBenjamin LaHaise struct skb_shared_info *shinfo; 1871da177e4SLinus Torvalds struct sk_buff *skb; 1881da177e4SLinus Torvalds u8 *data; 189c93bdd0eSMel Gorman bool pfmemalloc; 1901da177e4SLinus Torvalds 191c93bdd0eSMel Gorman cache = (flags & SKB_ALLOC_FCLONE) 192c93bdd0eSMel Gorman ? skbuff_fclone_cache : skbuff_head_cache; 193c93bdd0eSMel Gorman 194c93bdd0eSMel Gorman if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX)) 195c93bdd0eSMel Gorman gfp_mask |= __GFP_MEMALLOC; 1968798b3fbSHerbert Xu 1971da177e4SLinus Torvalds /* Get the HEAD */ 198b30973f8SChristoph Hellwig skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); 1991da177e4SLinus Torvalds if (!skb) 2001da177e4SLinus Torvalds goto out; 201ec7d2f2cSEric Dumazet prefetchw(skb); 2021da177e4SLinus Torvalds 20387fb4b7bSEric Dumazet /* We do our best to align skb_shared_info on a separate cache 20487fb4b7bSEric Dumazet * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives 20587fb4b7bSEric Dumazet * aligned memory blocks, unless SLUB/SLAB debug is enabled. 20687fb4b7bSEric Dumazet * Both skb->head and skb_shared_info are cache line aligned. 20787fb4b7bSEric Dumazet */ 208bc417e30STony Lindgren size = SKB_DATA_ALIGN(size); 20987fb4b7bSEric Dumazet size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 210c93bdd0eSMel Gorman data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc); 2111da177e4SLinus Torvalds if (!data) 2121da177e4SLinus Torvalds goto nodata; 21387fb4b7bSEric Dumazet /* kmalloc(size) might give us more room than requested. 21487fb4b7bSEric Dumazet * Put skb_shared_info exactly at the end of allocated zone, 21587fb4b7bSEric Dumazet * to allow max possible filling before reallocation. 21687fb4b7bSEric Dumazet */ 21787fb4b7bSEric Dumazet size = SKB_WITH_OVERHEAD(ksize(data)); 218ec7d2f2cSEric Dumazet prefetchw(data + size); 2191da177e4SLinus Torvalds 220ca0605a7SArnaldo Carvalho de Melo /* 221c8005785SJohannes Berg * Only clear those fields we need to clear, not those that we will 222c8005785SJohannes Berg * actually initialise below. Hence, don't put any more fields after 223c8005785SJohannes Berg * the tail pointer in struct sk_buff! 224ca0605a7SArnaldo Carvalho de Melo */ 225ca0605a7SArnaldo Carvalho de Melo memset(skb, 0, offsetof(struct sk_buff, tail)); 22687fb4b7bSEric Dumazet /* Account for allocated memory : skb + skb->head */ 22787fb4b7bSEric Dumazet skb->truesize = SKB_TRUESIZE(size); 228c93bdd0eSMel Gorman skb->pfmemalloc = pfmemalloc; 22963354797SReshetova, Elena refcount_set(&skb->users, 1); 2301da177e4SLinus Torvalds skb->head = data; 2311da177e4SLinus Torvalds skb->data = data; 23227a884dcSArnaldo Carvalho de Melo skb_reset_tail_pointer(skb); 2334305b541SArnaldo Carvalho de Melo skb->end = skb->tail + size; 23435d04610SCong Wang skb->mac_header = (typeof(skb->mac_header))~0U; 23535d04610SCong Wang skb->transport_header = (typeof(skb->transport_header))~0U; 23619633e12SStephen Hemminger 2374947d3efSBenjamin LaHaise /* make sure we initialize shinfo sequentially */ 2384947d3efSBenjamin LaHaise shinfo = skb_shinfo(skb); 239ec7d2f2cSEric Dumazet memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); 2404947d3efSBenjamin LaHaise atomic_set(&shinfo->dataref, 1); 2414947d3efSBenjamin LaHaise 242c93bdd0eSMel Gorman if (flags & SKB_ALLOC_FCLONE) { 243d0bf4a9eSEric Dumazet struct sk_buff_fclones *fclones; 2441da177e4SLinus Torvalds 245d0bf4a9eSEric Dumazet fclones = container_of(skb, struct sk_buff_fclones, skb1); 246d0bf4a9eSEric Dumazet 247d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_ORIG; 2482638595aSReshetova, Elena refcount_set(&fclones->fclone_ref, 1); 249d179cd12SDavid S. Miller 2506ffe75ebSEric Dumazet fclones->skb2.fclone = SKB_FCLONE_CLONE; 251d179cd12SDavid S. Miller } 2521da177e4SLinus Torvalds out: 2531da177e4SLinus Torvalds return skb; 2541da177e4SLinus Torvalds nodata: 2558798b3fbSHerbert Xu kmem_cache_free(cache, skb); 2561da177e4SLinus Torvalds skb = NULL; 2571da177e4SLinus Torvalds goto out; 2581da177e4SLinus Torvalds } 259b4ac530fSDavid S. Miller EXPORT_SYMBOL(__alloc_skb); 2601da177e4SLinus Torvalds 261ba0509b6SJesper Dangaard Brouer /* Caller must provide SKB that is memset cleared */ 262ba0509b6SJesper Dangaard Brouer static struct sk_buff *__build_skb_around(struct sk_buff *skb, 263ba0509b6SJesper Dangaard Brouer void *data, unsigned int frag_size) 264ba0509b6SJesper Dangaard Brouer { 265ba0509b6SJesper Dangaard Brouer struct skb_shared_info *shinfo; 266ba0509b6SJesper Dangaard Brouer unsigned int size = frag_size ? : ksize(data); 267ba0509b6SJesper Dangaard Brouer 268ba0509b6SJesper Dangaard Brouer size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 269ba0509b6SJesper Dangaard Brouer 270ba0509b6SJesper Dangaard Brouer /* Assumes caller memset cleared SKB */ 271ba0509b6SJesper Dangaard Brouer skb->truesize = SKB_TRUESIZE(size); 272ba0509b6SJesper Dangaard Brouer refcount_set(&skb->users, 1); 273ba0509b6SJesper Dangaard Brouer skb->head = data; 274ba0509b6SJesper Dangaard Brouer skb->data = data; 275ba0509b6SJesper Dangaard Brouer skb_reset_tail_pointer(skb); 276ba0509b6SJesper Dangaard Brouer skb->end = skb->tail + size; 277ba0509b6SJesper Dangaard Brouer skb->mac_header = (typeof(skb->mac_header))~0U; 278ba0509b6SJesper Dangaard Brouer skb->transport_header = (typeof(skb->transport_header))~0U; 279ba0509b6SJesper Dangaard Brouer 280ba0509b6SJesper Dangaard Brouer /* make sure we initialize shinfo sequentially */ 281ba0509b6SJesper Dangaard Brouer shinfo = skb_shinfo(skb); 282ba0509b6SJesper Dangaard Brouer memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); 283ba0509b6SJesper Dangaard Brouer atomic_set(&shinfo->dataref, 1); 284ba0509b6SJesper Dangaard Brouer 285ba0509b6SJesper Dangaard Brouer return skb; 286ba0509b6SJesper Dangaard Brouer } 287ba0509b6SJesper Dangaard Brouer 2881da177e4SLinus Torvalds /** 2892ea2f62cSEric Dumazet * __build_skb - build a network buffer 290b2b5ce9dSEric Dumazet * @data: data buffer provided by caller 2912ea2f62cSEric Dumazet * @frag_size: size of data, or 0 if head was kmalloced 292b2b5ce9dSEric Dumazet * 293b2b5ce9dSEric Dumazet * Allocate a new &sk_buff. Caller provides space holding head and 294deceb4c0SFlorian Fainelli * skb_shared_info. @data must have been allocated by kmalloc() only if 2952ea2f62cSEric Dumazet * @frag_size is 0, otherwise data should come from the page allocator 2962ea2f62cSEric Dumazet * or vmalloc() 297b2b5ce9dSEric Dumazet * The return is the new skb buffer. 298b2b5ce9dSEric Dumazet * On a failure the return is %NULL, and @data is not freed. 299b2b5ce9dSEric Dumazet * Notes : 300b2b5ce9dSEric Dumazet * Before IO, driver allocates only data buffer where NIC put incoming frame 301b2b5ce9dSEric Dumazet * Driver should add room at head (NET_SKB_PAD) and 302b2b5ce9dSEric Dumazet * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info)) 303b2b5ce9dSEric Dumazet * After IO, driver calls build_skb(), to allocate sk_buff and populate it 304b2b5ce9dSEric Dumazet * before giving packet to stack. 305b2b5ce9dSEric Dumazet * RX rings only contains data buffers, not full skbs. 306b2b5ce9dSEric Dumazet */ 3072ea2f62cSEric Dumazet struct sk_buff *__build_skb(void *data, unsigned int frag_size) 308b2b5ce9dSEric Dumazet { 309b2b5ce9dSEric Dumazet struct sk_buff *skb; 310b2b5ce9dSEric Dumazet 311b2b5ce9dSEric Dumazet skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC); 312ba0509b6SJesper Dangaard Brouer if (unlikely(!skb)) 313b2b5ce9dSEric Dumazet return NULL; 314b2b5ce9dSEric Dumazet 315b2b5ce9dSEric Dumazet memset(skb, 0, offsetof(struct sk_buff, tail)); 316b2b5ce9dSEric Dumazet 317ba0509b6SJesper Dangaard Brouer return __build_skb_around(skb, data, frag_size); 318b2b5ce9dSEric Dumazet } 3192ea2f62cSEric Dumazet 3202ea2f62cSEric Dumazet /* build_skb() is wrapper over __build_skb(), that specifically 3212ea2f62cSEric Dumazet * takes care of skb->head and skb->pfmemalloc 3222ea2f62cSEric Dumazet * This means that if @frag_size is not zero, then @data must be backed 3232ea2f62cSEric Dumazet * by a page fragment, not kmalloc() or vmalloc() 3242ea2f62cSEric Dumazet */ 3252ea2f62cSEric Dumazet struct sk_buff *build_skb(void *data, unsigned int frag_size) 3262ea2f62cSEric Dumazet { 3272ea2f62cSEric Dumazet struct sk_buff *skb = __build_skb(data, frag_size); 3282ea2f62cSEric Dumazet 3292ea2f62cSEric Dumazet if (skb && frag_size) { 3302ea2f62cSEric Dumazet skb->head_frag = 1; 3312f064f34SMichal Hocko if (page_is_pfmemalloc(virt_to_head_page(data))) 3322ea2f62cSEric Dumazet skb->pfmemalloc = 1; 3332ea2f62cSEric Dumazet } 3342ea2f62cSEric Dumazet return skb; 3352ea2f62cSEric Dumazet } 336b2b5ce9dSEric Dumazet EXPORT_SYMBOL(build_skb); 337b2b5ce9dSEric Dumazet 338ba0509b6SJesper Dangaard Brouer /** 339ba0509b6SJesper Dangaard Brouer * build_skb_around - build a network buffer around provided skb 340ba0509b6SJesper Dangaard Brouer * @skb: sk_buff provide by caller, must be memset cleared 341ba0509b6SJesper Dangaard Brouer * @data: data buffer provided by caller 342ba0509b6SJesper Dangaard Brouer * @frag_size: size of data, or 0 if head was kmalloced 343ba0509b6SJesper Dangaard Brouer */ 344ba0509b6SJesper Dangaard Brouer struct sk_buff *build_skb_around(struct sk_buff *skb, 345ba0509b6SJesper Dangaard Brouer void *data, unsigned int frag_size) 346ba0509b6SJesper Dangaard Brouer { 347ba0509b6SJesper Dangaard Brouer if (unlikely(!skb)) 348ba0509b6SJesper Dangaard Brouer return NULL; 349ba0509b6SJesper Dangaard Brouer 350ba0509b6SJesper Dangaard Brouer skb = __build_skb_around(skb, data, frag_size); 351ba0509b6SJesper Dangaard Brouer 352ba0509b6SJesper Dangaard Brouer if (skb && frag_size) { 353ba0509b6SJesper Dangaard Brouer skb->head_frag = 1; 354ba0509b6SJesper Dangaard Brouer if (page_is_pfmemalloc(virt_to_head_page(data))) 355ba0509b6SJesper Dangaard Brouer skb->pfmemalloc = 1; 356ba0509b6SJesper Dangaard Brouer } 357ba0509b6SJesper Dangaard Brouer return skb; 358ba0509b6SJesper Dangaard Brouer } 359ba0509b6SJesper Dangaard Brouer EXPORT_SYMBOL(build_skb_around); 360ba0509b6SJesper Dangaard Brouer 361795bb1c0SJesper Dangaard Brouer #define NAPI_SKB_CACHE_SIZE 64 362795bb1c0SJesper Dangaard Brouer 363795bb1c0SJesper Dangaard Brouer struct napi_alloc_cache { 364795bb1c0SJesper Dangaard Brouer struct page_frag_cache page; 365e0d7924aSAlexey Dobriyan unsigned int skb_count; 366795bb1c0SJesper Dangaard Brouer void *skb_cache[NAPI_SKB_CACHE_SIZE]; 367795bb1c0SJesper Dangaard Brouer }; 368795bb1c0SJesper Dangaard Brouer 369b63ae8caSAlexander Duyck static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache); 370795bb1c0SJesper Dangaard Brouer static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache); 371ffde7328SAlexander Duyck 372ffde7328SAlexander Duyck static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) 373ffde7328SAlexander Duyck { 374795bb1c0SJesper Dangaard Brouer struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); 3759451980aSAlexander Duyck 3768c2dd3e4SAlexander Duyck return page_frag_alloc(&nc->page, fragsz, gfp_mask); 377ffde7328SAlexander Duyck } 378ffde7328SAlexander Duyck 379ffde7328SAlexander Duyck void *napi_alloc_frag(unsigned int fragsz) 380ffde7328SAlexander Duyck { 3813bed3cc4SAlexander Duyck fragsz = SKB_DATA_ALIGN(fragsz); 3823bed3cc4SAlexander Duyck 383453f85d4SMel Gorman return __napi_alloc_frag(fragsz, GFP_ATOMIC); 384ffde7328SAlexander Duyck } 385ffde7328SAlexander Duyck EXPORT_SYMBOL(napi_alloc_frag); 386ffde7328SAlexander Duyck 3876f532612SEric Dumazet /** 3887ba7aeabSSebastian Andrzej Siewior * netdev_alloc_frag - allocate a page fragment 3897ba7aeabSSebastian Andrzej Siewior * @fragsz: fragment size 3907ba7aeabSSebastian Andrzej Siewior * 3917ba7aeabSSebastian Andrzej Siewior * Allocates a frag from a page for receive buffer. 3927ba7aeabSSebastian Andrzej Siewior * Uses GFP_ATOMIC allocations. 3937ba7aeabSSebastian Andrzej Siewior */ 3947ba7aeabSSebastian Andrzej Siewior void *netdev_alloc_frag(unsigned int fragsz) 3957ba7aeabSSebastian Andrzej Siewior { 3967ba7aeabSSebastian Andrzej Siewior struct page_frag_cache *nc; 3977ba7aeabSSebastian Andrzej Siewior void *data; 3987ba7aeabSSebastian Andrzej Siewior 3997ba7aeabSSebastian Andrzej Siewior fragsz = SKB_DATA_ALIGN(fragsz); 4007ba7aeabSSebastian Andrzej Siewior if (in_irq() || irqs_disabled()) { 4017ba7aeabSSebastian Andrzej Siewior nc = this_cpu_ptr(&netdev_alloc_cache); 4027ba7aeabSSebastian Andrzej Siewior data = page_frag_alloc(nc, fragsz, GFP_ATOMIC); 4037ba7aeabSSebastian Andrzej Siewior } else { 4047ba7aeabSSebastian Andrzej Siewior local_bh_disable(); 4057ba7aeabSSebastian Andrzej Siewior data = __napi_alloc_frag(fragsz, GFP_ATOMIC); 4067ba7aeabSSebastian Andrzej Siewior local_bh_enable(); 4077ba7aeabSSebastian Andrzej Siewior } 4087ba7aeabSSebastian Andrzej Siewior return data; 4097ba7aeabSSebastian Andrzej Siewior } 4107ba7aeabSSebastian Andrzej Siewior EXPORT_SYMBOL(netdev_alloc_frag); 4117ba7aeabSSebastian Andrzej Siewior 4127ba7aeabSSebastian Andrzej Siewior /** 413fd11a83dSAlexander Duyck * __netdev_alloc_skb - allocate an skbuff for rx on a specific device 414fd11a83dSAlexander Duyck * @dev: network device to receive on 415d7499160SMasanari Iida * @len: length to allocate 416fd11a83dSAlexander Duyck * @gfp_mask: get_free_pages mask, passed to alloc_skb 417fd11a83dSAlexander Duyck * 418fd11a83dSAlexander Duyck * Allocate a new &sk_buff and assign it a usage count of one. The 419fd11a83dSAlexander Duyck * buffer has NET_SKB_PAD headroom built in. Users should allocate 420fd11a83dSAlexander Duyck * the headroom they think they need without accounting for the 421fd11a83dSAlexander Duyck * built in space. The built in space is used for optimisations. 422fd11a83dSAlexander Duyck * 423fd11a83dSAlexander Duyck * %NULL is returned if there is no free memory. 424fd11a83dSAlexander Duyck */ 4259451980aSAlexander Duyck struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len, 4269451980aSAlexander Duyck gfp_t gfp_mask) 427fd11a83dSAlexander Duyck { 428b63ae8caSAlexander Duyck struct page_frag_cache *nc; 429fd11a83dSAlexander Duyck struct sk_buff *skb; 4309451980aSAlexander Duyck bool pfmemalloc; 4319451980aSAlexander Duyck void *data; 432fd11a83dSAlexander Duyck 4339451980aSAlexander Duyck len += NET_SKB_PAD; 434fd11a83dSAlexander Duyck 4359451980aSAlexander Duyck if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) || 436d0164adcSMel Gorman (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) { 437a080e7bdSAlexander Duyck skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE); 438a080e7bdSAlexander Duyck if (!skb) 439a080e7bdSAlexander Duyck goto skb_fail; 440a080e7bdSAlexander Duyck goto skb_success; 441a080e7bdSAlexander Duyck } 4429451980aSAlexander Duyck 4439451980aSAlexander Duyck len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 4449451980aSAlexander Duyck len = SKB_DATA_ALIGN(len); 4459451980aSAlexander Duyck 4469451980aSAlexander Duyck if (sk_memalloc_socks()) 4479451980aSAlexander Duyck gfp_mask |= __GFP_MEMALLOC; 4489451980aSAlexander Duyck 44992dcabd7SSebastian Andrzej Siewior if (in_irq() || irqs_disabled()) { 4509451980aSAlexander Duyck nc = this_cpu_ptr(&netdev_alloc_cache); 4518c2dd3e4SAlexander Duyck data = page_frag_alloc(nc, len, gfp_mask); 4529451980aSAlexander Duyck pfmemalloc = nc->pfmemalloc; 45392dcabd7SSebastian Andrzej Siewior } else { 45492dcabd7SSebastian Andrzej Siewior local_bh_disable(); 45592dcabd7SSebastian Andrzej Siewior nc = this_cpu_ptr(&napi_alloc_cache.page); 45692dcabd7SSebastian Andrzej Siewior data = page_frag_alloc(nc, len, gfp_mask); 45792dcabd7SSebastian Andrzej Siewior pfmemalloc = nc->pfmemalloc; 45892dcabd7SSebastian Andrzej Siewior local_bh_enable(); 45992dcabd7SSebastian Andrzej Siewior } 4609451980aSAlexander Duyck 4619451980aSAlexander Duyck if (unlikely(!data)) 4629451980aSAlexander Duyck return NULL; 4639451980aSAlexander Duyck 4649451980aSAlexander Duyck skb = __build_skb(data, len); 4659451980aSAlexander Duyck if (unlikely(!skb)) { 466181edb2bSAlexander Duyck skb_free_frag(data); 4679451980aSAlexander Duyck return NULL; 4689451980aSAlexander Duyck } 4699451980aSAlexander Duyck 4709451980aSAlexander Duyck if (pfmemalloc) 4719451980aSAlexander Duyck skb->pfmemalloc = 1; 4729451980aSAlexander Duyck skb->head_frag = 1; 4739451980aSAlexander Duyck 474a080e7bdSAlexander Duyck skb_success: 4758af27456SChristoph Hellwig skb_reserve(skb, NET_SKB_PAD); 4767b2e497aSChristoph Hellwig skb->dev = dev; 477fd11a83dSAlexander Duyck 478a080e7bdSAlexander Duyck skb_fail: 4798af27456SChristoph Hellwig return skb; 4808af27456SChristoph Hellwig } 481b4ac530fSDavid S. Miller EXPORT_SYMBOL(__netdev_alloc_skb); 4821da177e4SLinus Torvalds 483fd11a83dSAlexander Duyck /** 484fd11a83dSAlexander Duyck * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance 485fd11a83dSAlexander Duyck * @napi: napi instance this buffer was allocated for 486d7499160SMasanari Iida * @len: length to allocate 487fd11a83dSAlexander Duyck * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages 488fd11a83dSAlexander Duyck * 489fd11a83dSAlexander Duyck * Allocate a new sk_buff for use in NAPI receive. This buffer will 490fd11a83dSAlexander Duyck * attempt to allocate the head from a special reserved region used 491fd11a83dSAlexander Duyck * only for NAPI Rx allocation. By doing this we can save several 492fd11a83dSAlexander Duyck * CPU cycles by avoiding having to disable and re-enable IRQs. 493fd11a83dSAlexander Duyck * 494fd11a83dSAlexander Duyck * %NULL is returned if there is no free memory. 495fd11a83dSAlexander Duyck */ 4969451980aSAlexander Duyck struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, 4979451980aSAlexander Duyck gfp_t gfp_mask) 498fd11a83dSAlexander Duyck { 499795bb1c0SJesper Dangaard Brouer struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); 500fd11a83dSAlexander Duyck struct sk_buff *skb; 5019451980aSAlexander Duyck void *data; 502fd11a83dSAlexander Duyck 5039451980aSAlexander Duyck len += NET_SKB_PAD + NET_IP_ALIGN; 504fd11a83dSAlexander Duyck 5059451980aSAlexander Duyck if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) || 506d0164adcSMel Gorman (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) { 507a080e7bdSAlexander Duyck skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE); 508a080e7bdSAlexander Duyck if (!skb) 509a080e7bdSAlexander Duyck goto skb_fail; 510a080e7bdSAlexander Duyck goto skb_success; 511a080e7bdSAlexander Duyck } 5129451980aSAlexander Duyck 5139451980aSAlexander Duyck len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 5149451980aSAlexander Duyck len = SKB_DATA_ALIGN(len); 5159451980aSAlexander Duyck 5169451980aSAlexander Duyck if (sk_memalloc_socks()) 5179451980aSAlexander Duyck gfp_mask |= __GFP_MEMALLOC; 5189451980aSAlexander Duyck 5198c2dd3e4SAlexander Duyck data = page_frag_alloc(&nc->page, len, gfp_mask); 5209451980aSAlexander Duyck if (unlikely(!data)) 5219451980aSAlexander Duyck return NULL; 5229451980aSAlexander Duyck 5239451980aSAlexander Duyck skb = __build_skb(data, len); 5249451980aSAlexander Duyck if (unlikely(!skb)) { 525181edb2bSAlexander Duyck skb_free_frag(data); 5269451980aSAlexander Duyck return NULL; 5279451980aSAlexander Duyck } 5289451980aSAlexander Duyck 529795bb1c0SJesper Dangaard Brouer if (nc->page.pfmemalloc) 5309451980aSAlexander Duyck skb->pfmemalloc = 1; 5319451980aSAlexander Duyck skb->head_frag = 1; 5329451980aSAlexander Duyck 533a080e7bdSAlexander Duyck skb_success: 534fd11a83dSAlexander Duyck skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); 535fd11a83dSAlexander Duyck skb->dev = napi->dev; 536fd11a83dSAlexander Duyck 537a080e7bdSAlexander Duyck skb_fail: 538fd11a83dSAlexander Duyck return skb; 539fd11a83dSAlexander Duyck } 540fd11a83dSAlexander Duyck EXPORT_SYMBOL(__napi_alloc_skb); 541fd11a83dSAlexander Duyck 542654bed16SPeter Zijlstra void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, 54350269e19SEric Dumazet int size, unsigned int truesize) 544654bed16SPeter Zijlstra { 545654bed16SPeter Zijlstra skb_fill_page_desc(skb, i, page, off, size); 546654bed16SPeter Zijlstra skb->len += size; 547654bed16SPeter Zijlstra skb->data_len += size; 54850269e19SEric Dumazet skb->truesize += truesize; 549654bed16SPeter Zijlstra } 550654bed16SPeter Zijlstra EXPORT_SYMBOL(skb_add_rx_frag); 551654bed16SPeter Zijlstra 552f8e617e1SJason Wang void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size, 553f8e617e1SJason Wang unsigned int truesize) 554f8e617e1SJason Wang { 555f8e617e1SJason Wang skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 556f8e617e1SJason Wang 557f8e617e1SJason Wang skb_frag_size_add(frag, size); 558f8e617e1SJason Wang skb->len += size; 559f8e617e1SJason Wang skb->data_len += size; 560f8e617e1SJason Wang skb->truesize += truesize; 561f8e617e1SJason Wang } 562f8e617e1SJason Wang EXPORT_SYMBOL(skb_coalesce_rx_frag); 563f8e617e1SJason Wang 56427b437c8SHerbert Xu static void skb_drop_list(struct sk_buff **listp) 5651da177e4SLinus Torvalds { 566bd8a7036SEric Dumazet kfree_skb_list(*listp); 56727b437c8SHerbert Xu *listp = NULL; 5681da177e4SLinus Torvalds } 5691da177e4SLinus Torvalds 57027b437c8SHerbert Xu static inline void skb_drop_fraglist(struct sk_buff *skb) 57127b437c8SHerbert Xu { 57227b437c8SHerbert Xu skb_drop_list(&skb_shinfo(skb)->frag_list); 57327b437c8SHerbert Xu } 57427b437c8SHerbert Xu 5751da177e4SLinus Torvalds static void skb_clone_fraglist(struct sk_buff *skb) 5761da177e4SLinus Torvalds { 5771da177e4SLinus Torvalds struct sk_buff *list; 5781da177e4SLinus Torvalds 579fbb398a8SDavid S. Miller skb_walk_frags(skb, list) 5801da177e4SLinus Torvalds skb_get(list); 5811da177e4SLinus Torvalds } 5821da177e4SLinus Torvalds 583d3836f21SEric Dumazet static void skb_free_head(struct sk_buff *skb) 584d3836f21SEric Dumazet { 585181edb2bSAlexander Duyck unsigned char *head = skb->head; 586181edb2bSAlexander Duyck 587d3836f21SEric Dumazet if (skb->head_frag) 588181edb2bSAlexander Duyck skb_free_frag(head); 589d3836f21SEric Dumazet else 590181edb2bSAlexander Duyck kfree(head); 591d3836f21SEric Dumazet } 592d3836f21SEric Dumazet 5935bba1712SAdrian Bunk static void skb_release_data(struct sk_buff *skb) 5941da177e4SLinus Torvalds { 595ff04a771SEric Dumazet struct skb_shared_info *shinfo = skb_shinfo(skb); 5961da177e4SLinus Torvalds int i; 597ff04a771SEric Dumazet 598ff04a771SEric Dumazet if (skb->cloned && 599ff04a771SEric Dumazet atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, 600ff04a771SEric Dumazet &shinfo->dataref)) 601ff04a771SEric Dumazet return; 602ff04a771SEric Dumazet 603ff04a771SEric Dumazet for (i = 0; i < shinfo->nr_frags; i++) 604ff04a771SEric Dumazet __skb_frag_unref(&shinfo->frags[i]); 6051da177e4SLinus Torvalds 606ff04a771SEric Dumazet if (shinfo->frag_list) 607ff04a771SEric Dumazet kfree_skb_list(shinfo->frag_list); 6081da177e4SLinus Torvalds 6091f8b977aSWillem de Bruijn skb_zcopy_clear(skb, true); 610d3836f21SEric Dumazet skb_free_head(skb); 6111da177e4SLinus Torvalds } 6121da177e4SLinus Torvalds 6131da177e4SLinus Torvalds /* 6141da177e4SLinus Torvalds * Free an skbuff by memory without cleaning the state. 6151da177e4SLinus Torvalds */ 6162d4baff8SHerbert Xu static void kfree_skbmem(struct sk_buff *skb) 6171da177e4SLinus Torvalds { 618d0bf4a9eSEric Dumazet struct sk_buff_fclones *fclones; 619d179cd12SDavid S. Miller 620d179cd12SDavid S. Miller switch (skb->fclone) { 621d179cd12SDavid S. Miller case SKB_FCLONE_UNAVAILABLE: 6221da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 6236ffe75ebSEric Dumazet return; 624d179cd12SDavid S. Miller 625d179cd12SDavid S. Miller case SKB_FCLONE_ORIG: 626d0bf4a9eSEric Dumazet fclones = container_of(skb, struct sk_buff_fclones, skb1); 6276ffe75ebSEric Dumazet 6286ffe75ebSEric Dumazet /* We usually free the clone (TX completion) before original skb 6296ffe75ebSEric Dumazet * This test would have no chance to be true for the clone, 6306ffe75ebSEric Dumazet * while here, branch prediction will be good. 6316ffe75ebSEric Dumazet */ 6322638595aSReshetova, Elena if (refcount_read(&fclones->fclone_ref) == 1) 6336ffe75ebSEric Dumazet goto fastpath; 634d179cd12SDavid S. Miller break; 635d179cd12SDavid S. Miller 6366ffe75ebSEric Dumazet default: /* SKB_FCLONE_CLONE */ 637d0bf4a9eSEric Dumazet fclones = container_of(skb, struct sk_buff_fclones, skb2); 638d179cd12SDavid S. Miller break; 6393ff50b79SStephen Hemminger } 6402638595aSReshetova, Elena if (!refcount_dec_and_test(&fclones->fclone_ref)) 6416ffe75ebSEric Dumazet return; 6426ffe75ebSEric Dumazet fastpath: 6436ffe75ebSEric Dumazet kmem_cache_free(skbuff_fclone_cache, fclones); 6441da177e4SLinus Torvalds } 6451da177e4SLinus Torvalds 6460a463c78SPaolo Abeni void skb_release_head_state(struct sk_buff *skb) 6471da177e4SLinus Torvalds { 648adf30907SEric Dumazet skb_dst_drop(skb); 6491da177e4SLinus Torvalds if (skb->destructor) { 6509c2b3328SStephen Hemminger WARN_ON(in_irq()); 6511da177e4SLinus Torvalds skb->destructor(skb); 6521da177e4SLinus Torvalds } 653a3bf7ae9SIgor Maravić #if IS_ENABLED(CONFIG_NF_CONNTRACK) 654cb9c6836SFlorian Westphal nf_conntrack_put(skb_nfct(skb)); 6552fc72c7bSKOVACS Krisztian #endif 656df5042f4SFlorian Westphal skb_ext_put(skb); 65704a4bb55SLennert Buytenhek } 65804a4bb55SLennert Buytenhek 65904a4bb55SLennert Buytenhek /* Free everything but the sk_buff shell. */ 66004a4bb55SLennert Buytenhek static void skb_release_all(struct sk_buff *skb) 66104a4bb55SLennert Buytenhek { 66204a4bb55SLennert Buytenhek skb_release_head_state(skb); 663a28b1b90SFlorian Westphal if (likely(skb->head)) 6642d4baff8SHerbert Xu skb_release_data(skb); 6652d4baff8SHerbert Xu } 6661da177e4SLinus Torvalds 6672d4baff8SHerbert Xu /** 6682d4baff8SHerbert Xu * __kfree_skb - private function 6692d4baff8SHerbert Xu * @skb: buffer 6702d4baff8SHerbert Xu * 6712d4baff8SHerbert Xu * Free an sk_buff. Release anything attached to the buffer. 6722d4baff8SHerbert Xu * Clean the state. This is an internal helper function. Users should 6732d4baff8SHerbert Xu * always call kfree_skb 6742d4baff8SHerbert Xu */ 6752d4baff8SHerbert Xu 6762d4baff8SHerbert Xu void __kfree_skb(struct sk_buff *skb) 6772d4baff8SHerbert Xu { 6782d4baff8SHerbert Xu skb_release_all(skb); 6791da177e4SLinus Torvalds kfree_skbmem(skb); 6801da177e4SLinus Torvalds } 681b4ac530fSDavid S. Miller EXPORT_SYMBOL(__kfree_skb); 6821da177e4SLinus Torvalds 6831da177e4SLinus Torvalds /** 684231d06aeSJörn Engel * kfree_skb - free an sk_buff 685231d06aeSJörn Engel * @skb: buffer to free 686231d06aeSJörn Engel * 687231d06aeSJörn Engel * Drop a reference to the buffer and free it if the usage count has 688231d06aeSJörn Engel * hit zero. 689231d06aeSJörn Engel */ 690231d06aeSJörn Engel void kfree_skb(struct sk_buff *skb) 691231d06aeSJörn Engel { 6923889a803SPaolo Abeni if (!skb_unref(skb)) 693231d06aeSJörn Engel return; 6943889a803SPaolo Abeni 695ead2ceb0SNeil Horman trace_kfree_skb(skb, __builtin_return_address(0)); 696231d06aeSJörn Engel __kfree_skb(skb); 697231d06aeSJörn Engel } 698b4ac530fSDavid S. Miller EXPORT_SYMBOL(kfree_skb); 699231d06aeSJörn Engel 700bd8a7036SEric Dumazet void kfree_skb_list(struct sk_buff *segs) 701bd8a7036SEric Dumazet { 702bd8a7036SEric Dumazet while (segs) { 703bd8a7036SEric Dumazet struct sk_buff *next = segs->next; 704bd8a7036SEric Dumazet 705bd8a7036SEric Dumazet kfree_skb(segs); 706bd8a7036SEric Dumazet segs = next; 707bd8a7036SEric Dumazet } 708bd8a7036SEric Dumazet } 709bd8a7036SEric Dumazet EXPORT_SYMBOL(kfree_skb_list); 710bd8a7036SEric Dumazet 7116413139dSWillem de Bruijn /* Dump skb information and contents. 7126413139dSWillem de Bruijn * 7136413139dSWillem de Bruijn * Must only be called from net_ratelimit()-ed paths. 7146413139dSWillem de Bruijn * 715302af7c6SVladimir Oltean * Dumps whole packets if full_pkt, only headers otherwise. 7166413139dSWillem de Bruijn */ 7176413139dSWillem de Bruijn void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt) 7186413139dSWillem de Bruijn { 7196413139dSWillem de Bruijn struct skb_shared_info *sh = skb_shinfo(skb); 7206413139dSWillem de Bruijn struct net_device *dev = skb->dev; 7216413139dSWillem de Bruijn struct sock *sk = skb->sk; 7226413139dSWillem de Bruijn struct sk_buff *list_skb; 7236413139dSWillem de Bruijn bool has_mac, has_trans; 7246413139dSWillem de Bruijn int headroom, tailroom; 7256413139dSWillem de Bruijn int i, len, seg_len; 7266413139dSWillem de Bruijn 7276413139dSWillem de Bruijn if (full_pkt) 7286413139dSWillem de Bruijn len = skb->len; 7296413139dSWillem de Bruijn else 7306413139dSWillem de Bruijn len = min_t(int, skb->len, MAX_HEADER + 128); 7316413139dSWillem de Bruijn 7326413139dSWillem de Bruijn headroom = skb_headroom(skb); 7336413139dSWillem de Bruijn tailroom = skb_tailroom(skb); 7346413139dSWillem de Bruijn 7356413139dSWillem de Bruijn has_mac = skb_mac_header_was_set(skb); 7366413139dSWillem de Bruijn has_trans = skb_transport_header_was_set(skb); 7376413139dSWillem de Bruijn 7386413139dSWillem de Bruijn printk("%sskb len=%u headroom=%u headlen=%u tailroom=%u\n" 7396413139dSWillem de Bruijn "mac=(%d,%d) net=(%d,%d) trans=%d\n" 7406413139dSWillem de Bruijn "shinfo(txflags=%u nr_frags=%u gso(size=%hu type=%u segs=%hu))\n" 7416413139dSWillem de Bruijn "csum(0x%x ip_summed=%u complete_sw=%u valid=%u level=%u)\n" 7426413139dSWillem de Bruijn "hash(0x%x sw=%u l4=%u) proto=0x%04x pkttype=%u iif=%d\n", 7436413139dSWillem de Bruijn level, skb->len, headroom, skb_headlen(skb), tailroom, 7446413139dSWillem de Bruijn has_mac ? skb->mac_header : -1, 7456413139dSWillem de Bruijn has_mac ? skb_mac_header_len(skb) : -1, 7466413139dSWillem de Bruijn skb->network_header, 7476413139dSWillem de Bruijn has_trans ? skb_network_header_len(skb) : -1, 7486413139dSWillem de Bruijn has_trans ? skb->transport_header : -1, 7496413139dSWillem de Bruijn sh->tx_flags, sh->nr_frags, 7506413139dSWillem de Bruijn sh->gso_size, sh->gso_type, sh->gso_segs, 7516413139dSWillem de Bruijn skb->csum, skb->ip_summed, skb->csum_complete_sw, 7526413139dSWillem de Bruijn skb->csum_valid, skb->csum_level, 7536413139dSWillem de Bruijn skb->hash, skb->sw_hash, skb->l4_hash, 7546413139dSWillem de Bruijn ntohs(skb->protocol), skb->pkt_type, skb->skb_iif); 7556413139dSWillem de Bruijn 7566413139dSWillem de Bruijn if (dev) 7576413139dSWillem de Bruijn printk("%sdev name=%s feat=0x%pNF\n", 7586413139dSWillem de Bruijn level, dev->name, &dev->features); 7596413139dSWillem de Bruijn if (sk) 760db8051f3SQian Cai printk("%ssk family=%hu type=%u proto=%u\n", 7616413139dSWillem de Bruijn level, sk->sk_family, sk->sk_type, sk->sk_protocol); 7626413139dSWillem de Bruijn 7636413139dSWillem de Bruijn if (full_pkt && headroom) 7646413139dSWillem de Bruijn print_hex_dump(level, "skb headroom: ", DUMP_PREFIX_OFFSET, 7656413139dSWillem de Bruijn 16, 1, skb->head, headroom, false); 7666413139dSWillem de Bruijn 7676413139dSWillem de Bruijn seg_len = min_t(int, skb_headlen(skb), len); 7686413139dSWillem de Bruijn if (seg_len) 7696413139dSWillem de Bruijn print_hex_dump(level, "skb linear: ", DUMP_PREFIX_OFFSET, 7706413139dSWillem de Bruijn 16, 1, skb->data, seg_len, false); 7716413139dSWillem de Bruijn len -= seg_len; 7726413139dSWillem de Bruijn 7736413139dSWillem de Bruijn if (full_pkt && tailroom) 7746413139dSWillem de Bruijn print_hex_dump(level, "skb tailroom: ", DUMP_PREFIX_OFFSET, 7756413139dSWillem de Bruijn 16, 1, skb_tail_pointer(skb), tailroom, false); 7766413139dSWillem de Bruijn 7776413139dSWillem de Bruijn for (i = 0; len && i < skb_shinfo(skb)->nr_frags; i++) { 7786413139dSWillem de Bruijn skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 7796413139dSWillem de Bruijn u32 p_off, p_len, copied; 7806413139dSWillem de Bruijn struct page *p; 7816413139dSWillem de Bruijn u8 *vaddr; 7826413139dSWillem de Bruijn 783b54c9d5bSJonathan Lemon skb_frag_foreach_page(frag, skb_frag_off(frag), 7846413139dSWillem de Bruijn skb_frag_size(frag), p, p_off, p_len, 7856413139dSWillem de Bruijn copied) { 7866413139dSWillem de Bruijn seg_len = min_t(int, p_len, len); 7876413139dSWillem de Bruijn vaddr = kmap_atomic(p); 7886413139dSWillem de Bruijn print_hex_dump(level, "skb frag: ", 7896413139dSWillem de Bruijn DUMP_PREFIX_OFFSET, 7906413139dSWillem de Bruijn 16, 1, vaddr + p_off, seg_len, false); 7916413139dSWillem de Bruijn kunmap_atomic(vaddr); 7926413139dSWillem de Bruijn len -= seg_len; 7936413139dSWillem de Bruijn if (!len) 7946413139dSWillem de Bruijn break; 7956413139dSWillem de Bruijn } 7966413139dSWillem de Bruijn } 7976413139dSWillem de Bruijn 7986413139dSWillem de Bruijn if (full_pkt && skb_has_frag_list(skb)) { 7996413139dSWillem de Bruijn printk("skb fraglist:\n"); 8006413139dSWillem de Bruijn skb_walk_frags(skb, list_skb) 8016413139dSWillem de Bruijn skb_dump(level, list_skb, true); 8026413139dSWillem de Bruijn } 8036413139dSWillem de Bruijn } 8046413139dSWillem de Bruijn EXPORT_SYMBOL(skb_dump); 8056413139dSWillem de Bruijn 806d1a203eaSStephen Hemminger /** 80725121173SMichael S. Tsirkin * skb_tx_error - report an sk_buff xmit error 80825121173SMichael S. Tsirkin * @skb: buffer that triggered an error 80925121173SMichael S. Tsirkin * 81025121173SMichael S. Tsirkin * Report xmit error if a device callback is tracking this skb. 81125121173SMichael S. Tsirkin * skb must be freed afterwards. 81225121173SMichael S. Tsirkin */ 81325121173SMichael S. Tsirkin void skb_tx_error(struct sk_buff *skb) 81425121173SMichael S. Tsirkin { 8151f8b977aSWillem de Bruijn skb_zcopy_clear(skb, true); 81625121173SMichael S. Tsirkin } 81725121173SMichael S. Tsirkin EXPORT_SYMBOL(skb_tx_error); 81825121173SMichael S. Tsirkin 819be769db2SHerbert Xu #ifdef CONFIG_TRACEPOINTS 82025121173SMichael S. Tsirkin /** 821ead2ceb0SNeil Horman * consume_skb - free an skbuff 822ead2ceb0SNeil Horman * @skb: buffer to free 823ead2ceb0SNeil Horman * 824ead2ceb0SNeil Horman * Drop a ref to the buffer and free it if the usage count has hit zero 825ead2ceb0SNeil Horman * Functions identically to kfree_skb, but kfree_skb assumes that the frame 826ead2ceb0SNeil Horman * is being dropped after a failure and notes that 827ead2ceb0SNeil Horman */ 828ead2ceb0SNeil Horman void consume_skb(struct sk_buff *skb) 829ead2ceb0SNeil Horman { 8303889a803SPaolo Abeni if (!skb_unref(skb)) 831ead2ceb0SNeil Horman return; 8323889a803SPaolo Abeni 83307dc22e7SKoki Sanagi trace_consume_skb(skb); 834ead2ceb0SNeil Horman __kfree_skb(skb); 835ead2ceb0SNeil Horman } 836ead2ceb0SNeil Horman EXPORT_SYMBOL(consume_skb); 837be769db2SHerbert Xu #endif 838ead2ceb0SNeil Horman 8390a463c78SPaolo Abeni /** 8400a463c78SPaolo Abeni * consume_stateless_skb - free an skbuff, assuming it is stateless 8410a463c78SPaolo Abeni * @skb: buffer to free 8420a463c78SPaolo Abeni * 843ca2c1418SPaolo Abeni * Alike consume_skb(), but this variant assumes that this is the last 844ca2c1418SPaolo Abeni * skb reference and all the head states have been already dropped 8450a463c78SPaolo Abeni */ 846ca2c1418SPaolo Abeni void __consume_stateless_skb(struct sk_buff *skb) 8470a463c78SPaolo Abeni { 8480a463c78SPaolo Abeni trace_consume_skb(skb); 8490a463c78SPaolo Abeni skb_release_data(skb); 8500a463c78SPaolo Abeni kfree_skbmem(skb); 8510a463c78SPaolo Abeni } 8520a463c78SPaolo Abeni 853795bb1c0SJesper Dangaard Brouer void __kfree_skb_flush(void) 854795bb1c0SJesper Dangaard Brouer { 855795bb1c0SJesper Dangaard Brouer struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); 856795bb1c0SJesper Dangaard Brouer 857795bb1c0SJesper Dangaard Brouer /* flush skb_cache if containing objects */ 858795bb1c0SJesper Dangaard Brouer if (nc->skb_count) { 859795bb1c0SJesper Dangaard Brouer kmem_cache_free_bulk(skbuff_head_cache, nc->skb_count, 860795bb1c0SJesper Dangaard Brouer nc->skb_cache); 861795bb1c0SJesper Dangaard Brouer nc->skb_count = 0; 862795bb1c0SJesper Dangaard Brouer } 863795bb1c0SJesper Dangaard Brouer } 864795bb1c0SJesper Dangaard Brouer 86515fad714SJesper Dangaard Brouer static inline void _kfree_skb_defer(struct sk_buff *skb) 866795bb1c0SJesper Dangaard Brouer { 867795bb1c0SJesper Dangaard Brouer struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); 868795bb1c0SJesper Dangaard Brouer 869795bb1c0SJesper Dangaard Brouer /* drop skb->head and call any destructors for packet */ 870795bb1c0SJesper Dangaard Brouer skb_release_all(skb); 871795bb1c0SJesper Dangaard Brouer 872795bb1c0SJesper Dangaard Brouer /* record skb to CPU local list */ 873795bb1c0SJesper Dangaard Brouer nc->skb_cache[nc->skb_count++] = skb; 874795bb1c0SJesper Dangaard Brouer 875795bb1c0SJesper Dangaard Brouer #ifdef CONFIG_SLUB 876795bb1c0SJesper Dangaard Brouer /* SLUB writes into objects when freeing */ 877795bb1c0SJesper Dangaard Brouer prefetchw(skb); 878795bb1c0SJesper Dangaard Brouer #endif 879795bb1c0SJesper Dangaard Brouer 880795bb1c0SJesper Dangaard Brouer /* flush skb_cache if it is filled */ 881795bb1c0SJesper Dangaard Brouer if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) { 882795bb1c0SJesper Dangaard Brouer kmem_cache_free_bulk(skbuff_head_cache, NAPI_SKB_CACHE_SIZE, 883795bb1c0SJesper Dangaard Brouer nc->skb_cache); 884795bb1c0SJesper Dangaard Brouer nc->skb_count = 0; 885795bb1c0SJesper Dangaard Brouer } 886795bb1c0SJesper Dangaard Brouer } 88715fad714SJesper Dangaard Brouer void __kfree_skb_defer(struct sk_buff *skb) 88815fad714SJesper Dangaard Brouer { 88915fad714SJesper Dangaard Brouer _kfree_skb_defer(skb); 89015fad714SJesper Dangaard Brouer } 891795bb1c0SJesper Dangaard Brouer 892795bb1c0SJesper Dangaard Brouer void napi_consume_skb(struct sk_buff *skb, int budget) 893795bb1c0SJesper Dangaard Brouer { 894885eb0a5SJesper Dangaard Brouer /* Zero budget indicate non-NAPI context called us, like netpoll */ 895795bb1c0SJesper Dangaard Brouer if (unlikely(!budget)) { 896885eb0a5SJesper Dangaard Brouer dev_consume_skb_any(skb); 897795bb1c0SJesper Dangaard Brouer return; 898795bb1c0SJesper Dangaard Brouer } 899795bb1c0SJesper Dangaard Brouer 9007608894eSPaolo Abeni if (!skb_unref(skb)) 901795bb1c0SJesper Dangaard Brouer return; 9027608894eSPaolo Abeni 903795bb1c0SJesper Dangaard Brouer /* if reaching here SKB is ready to free */ 904795bb1c0SJesper Dangaard Brouer trace_consume_skb(skb); 905795bb1c0SJesper Dangaard Brouer 906795bb1c0SJesper Dangaard Brouer /* if SKB is a clone, don't handle this case */ 907abbdb5a7SEric Dumazet if (skb->fclone != SKB_FCLONE_UNAVAILABLE) { 908795bb1c0SJesper Dangaard Brouer __kfree_skb(skb); 909795bb1c0SJesper Dangaard Brouer return; 910795bb1c0SJesper Dangaard Brouer } 911795bb1c0SJesper Dangaard Brouer 91215fad714SJesper Dangaard Brouer _kfree_skb_defer(skb); 913795bb1c0SJesper Dangaard Brouer } 914795bb1c0SJesper Dangaard Brouer EXPORT_SYMBOL(napi_consume_skb); 915795bb1c0SJesper Dangaard Brouer 916b1937227SEric Dumazet /* Make sure a field is enclosed inside headers_start/headers_end section */ 917b1937227SEric Dumazet #define CHECK_SKB_FIELD(field) \ 918b1937227SEric Dumazet BUILD_BUG_ON(offsetof(struct sk_buff, field) < \ 919b1937227SEric Dumazet offsetof(struct sk_buff, headers_start)); \ 920b1937227SEric Dumazet BUILD_BUG_ON(offsetof(struct sk_buff, field) > \ 921b1937227SEric Dumazet offsetof(struct sk_buff, headers_end)); \ 922b1937227SEric Dumazet 923dec18810SHerbert Xu static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 924dec18810SHerbert Xu { 925dec18810SHerbert Xu new->tstamp = old->tstamp; 926b1937227SEric Dumazet /* We do not copy old->sk */ 927dec18810SHerbert Xu new->dev = old->dev; 928b1937227SEric Dumazet memcpy(new->cb, old->cb, sizeof(old->cb)); 9297fee226aSEric Dumazet skb_dst_copy(new, old); 930df5042f4SFlorian Westphal __skb_ext_copy(new, old); 931b1937227SEric Dumazet __nf_copy(new, old, false); 9326aa895b0SPatrick McHardy 933b1937227SEric Dumazet /* Note : this field could be in headers_start/headers_end section 934b1937227SEric Dumazet * It is not yet because we do not want to have a 16 bit hole 935b1937227SEric Dumazet */ 936b1937227SEric Dumazet new->queue_mapping = old->queue_mapping; 93706021292SEliezer Tamir 938b1937227SEric Dumazet memcpy(&new->headers_start, &old->headers_start, 939b1937227SEric Dumazet offsetof(struct sk_buff, headers_end) - 940b1937227SEric Dumazet offsetof(struct sk_buff, headers_start)); 941b1937227SEric Dumazet CHECK_SKB_FIELD(protocol); 942b1937227SEric Dumazet CHECK_SKB_FIELD(csum); 943b1937227SEric Dumazet CHECK_SKB_FIELD(hash); 944b1937227SEric Dumazet CHECK_SKB_FIELD(priority); 945b1937227SEric Dumazet CHECK_SKB_FIELD(skb_iif); 946b1937227SEric Dumazet CHECK_SKB_FIELD(vlan_proto); 947b1937227SEric Dumazet CHECK_SKB_FIELD(vlan_tci); 948b1937227SEric Dumazet CHECK_SKB_FIELD(transport_header); 949b1937227SEric Dumazet CHECK_SKB_FIELD(network_header); 950b1937227SEric Dumazet CHECK_SKB_FIELD(mac_header); 951b1937227SEric Dumazet CHECK_SKB_FIELD(inner_protocol); 952b1937227SEric Dumazet CHECK_SKB_FIELD(inner_transport_header); 953b1937227SEric Dumazet CHECK_SKB_FIELD(inner_network_header); 954b1937227SEric Dumazet CHECK_SKB_FIELD(inner_mac_header); 955b1937227SEric Dumazet CHECK_SKB_FIELD(mark); 956b1937227SEric Dumazet #ifdef CONFIG_NETWORK_SECMARK 957b1937227SEric Dumazet CHECK_SKB_FIELD(secmark); 958b1937227SEric Dumazet #endif 959e0d1095aSCong Wang #ifdef CONFIG_NET_RX_BUSY_POLL 960b1937227SEric Dumazet CHECK_SKB_FIELD(napi_id); 96106021292SEliezer Tamir #endif 9622bd82484SEric Dumazet #ifdef CONFIG_XPS 9632bd82484SEric Dumazet CHECK_SKB_FIELD(sender_cpu); 9642bd82484SEric Dumazet #endif 965b1937227SEric Dumazet #ifdef CONFIG_NET_SCHED 966b1937227SEric Dumazet CHECK_SKB_FIELD(tc_index); 967b1937227SEric Dumazet #endif 968b1937227SEric Dumazet 969dec18810SHerbert Xu } 970dec18810SHerbert Xu 97182c49a35SHerbert Xu /* 97282c49a35SHerbert Xu * You should not add any new code to this function. Add it to 97382c49a35SHerbert Xu * __copy_skb_header above instead. 97482c49a35SHerbert Xu */ 975e0053ec0SHerbert Xu static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) 9761da177e4SLinus Torvalds { 9771da177e4SLinus Torvalds #define C(x) n->x = skb->x 9781da177e4SLinus Torvalds 9791da177e4SLinus Torvalds n->next = n->prev = NULL; 9801da177e4SLinus Torvalds n->sk = NULL; 981dec18810SHerbert Xu __copy_skb_header(n, skb); 982dec18810SHerbert Xu 9831da177e4SLinus Torvalds C(len); 9841da177e4SLinus Torvalds C(data_len); 9853e6b3b2eSAlexey Dobriyan C(mac_len); 986334a8132SPatrick McHardy n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len; 98702f1c89dSPaul Moore n->cloned = 1; 9881da177e4SLinus Torvalds n->nohdr = 0; 989b13dda9fSEric Dumazet n->peeked = 0; 990e78bfb07SStefano Brivio C(pfmemalloc); 9911da177e4SLinus Torvalds n->destructor = NULL; 9921da177e4SLinus Torvalds C(tail); 9931da177e4SLinus Torvalds C(end); 99402f1c89dSPaul Moore C(head); 995d3836f21SEric Dumazet C(head_frag); 99602f1c89dSPaul Moore C(data); 99702f1c89dSPaul Moore C(truesize); 99863354797SReshetova, Elena refcount_set(&n->users, 1); 9991da177e4SLinus Torvalds 10001da177e4SLinus Torvalds atomic_inc(&(skb_shinfo(skb)->dataref)); 10011da177e4SLinus Torvalds skb->cloned = 1; 10021da177e4SLinus Torvalds 10031da177e4SLinus Torvalds return n; 1004e0053ec0SHerbert Xu #undef C 1005e0053ec0SHerbert Xu } 1006e0053ec0SHerbert Xu 1007e0053ec0SHerbert Xu /** 1008da29e4b4SJakub Kicinski * alloc_skb_for_msg() - allocate sk_buff to wrap frag list forming a msg 1009da29e4b4SJakub Kicinski * @first: first sk_buff of the msg 1010da29e4b4SJakub Kicinski */ 1011da29e4b4SJakub Kicinski struct sk_buff *alloc_skb_for_msg(struct sk_buff *first) 1012da29e4b4SJakub Kicinski { 1013da29e4b4SJakub Kicinski struct sk_buff *n; 1014da29e4b4SJakub Kicinski 1015da29e4b4SJakub Kicinski n = alloc_skb(0, GFP_ATOMIC); 1016da29e4b4SJakub Kicinski if (!n) 1017da29e4b4SJakub Kicinski return NULL; 1018da29e4b4SJakub Kicinski 1019da29e4b4SJakub Kicinski n->len = first->len; 1020da29e4b4SJakub Kicinski n->data_len = first->len; 1021da29e4b4SJakub Kicinski n->truesize = first->truesize; 1022da29e4b4SJakub Kicinski 1023da29e4b4SJakub Kicinski skb_shinfo(n)->frag_list = first; 1024da29e4b4SJakub Kicinski 1025da29e4b4SJakub Kicinski __copy_skb_header(n, first); 1026da29e4b4SJakub Kicinski n->destructor = NULL; 1027da29e4b4SJakub Kicinski 1028da29e4b4SJakub Kicinski return n; 1029da29e4b4SJakub Kicinski } 1030da29e4b4SJakub Kicinski EXPORT_SYMBOL_GPL(alloc_skb_for_msg); 1031da29e4b4SJakub Kicinski 1032da29e4b4SJakub Kicinski /** 1033e0053ec0SHerbert Xu * skb_morph - morph one skb into another 1034e0053ec0SHerbert Xu * @dst: the skb to receive the contents 1035e0053ec0SHerbert Xu * @src: the skb to supply the contents 1036e0053ec0SHerbert Xu * 1037e0053ec0SHerbert Xu * This is identical to skb_clone except that the target skb is 1038e0053ec0SHerbert Xu * supplied by the user. 1039e0053ec0SHerbert Xu * 1040e0053ec0SHerbert Xu * The target skb is returned upon exit. 1041e0053ec0SHerbert Xu */ 1042e0053ec0SHerbert Xu struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src) 1043e0053ec0SHerbert Xu { 10442d4baff8SHerbert Xu skb_release_all(dst); 1045e0053ec0SHerbert Xu return __skb_clone(dst, src); 1046e0053ec0SHerbert Xu } 1047e0053ec0SHerbert Xu EXPORT_SYMBOL_GPL(skb_morph); 1048e0053ec0SHerbert Xu 10496f89dbceSSowmini Varadhan int mm_account_pinned_pages(struct mmpin *mmp, size_t size) 1050a91dbff5SWillem de Bruijn { 1051a91dbff5SWillem de Bruijn unsigned long max_pg, num_pg, new_pg, old_pg; 1052a91dbff5SWillem de Bruijn struct user_struct *user; 1053a91dbff5SWillem de Bruijn 1054a91dbff5SWillem de Bruijn if (capable(CAP_IPC_LOCK) || !size) 1055a91dbff5SWillem de Bruijn return 0; 1056a91dbff5SWillem de Bruijn 1057a91dbff5SWillem de Bruijn num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */ 1058a91dbff5SWillem de Bruijn max_pg = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 1059a91dbff5SWillem de Bruijn user = mmp->user ? : current_user(); 1060a91dbff5SWillem de Bruijn 1061a91dbff5SWillem de Bruijn do { 1062a91dbff5SWillem de Bruijn old_pg = atomic_long_read(&user->locked_vm); 1063a91dbff5SWillem de Bruijn new_pg = old_pg + num_pg; 1064a91dbff5SWillem de Bruijn if (new_pg > max_pg) 1065a91dbff5SWillem de Bruijn return -ENOBUFS; 1066a91dbff5SWillem de Bruijn } while (atomic_long_cmpxchg(&user->locked_vm, old_pg, new_pg) != 1067a91dbff5SWillem de Bruijn old_pg); 1068a91dbff5SWillem de Bruijn 1069a91dbff5SWillem de Bruijn if (!mmp->user) { 1070a91dbff5SWillem de Bruijn mmp->user = get_uid(user); 1071a91dbff5SWillem de Bruijn mmp->num_pg = num_pg; 1072a91dbff5SWillem de Bruijn } else { 1073a91dbff5SWillem de Bruijn mmp->num_pg += num_pg; 1074a91dbff5SWillem de Bruijn } 1075a91dbff5SWillem de Bruijn 1076a91dbff5SWillem de Bruijn return 0; 1077a91dbff5SWillem de Bruijn } 10786f89dbceSSowmini Varadhan EXPORT_SYMBOL_GPL(mm_account_pinned_pages); 1079a91dbff5SWillem de Bruijn 10806f89dbceSSowmini Varadhan void mm_unaccount_pinned_pages(struct mmpin *mmp) 1081a91dbff5SWillem de Bruijn { 1082a91dbff5SWillem de Bruijn if (mmp->user) { 1083a91dbff5SWillem de Bruijn atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm); 1084a91dbff5SWillem de Bruijn free_uid(mmp->user); 1085a91dbff5SWillem de Bruijn } 1086a91dbff5SWillem de Bruijn } 10876f89dbceSSowmini Varadhan EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages); 1088a91dbff5SWillem de Bruijn 108952267790SWillem de Bruijn struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size) 109052267790SWillem de Bruijn { 109152267790SWillem de Bruijn struct ubuf_info *uarg; 109252267790SWillem de Bruijn struct sk_buff *skb; 109352267790SWillem de Bruijn 109452267790SWillem de Bruijn WARN_ON_ONCE(!in_task()); 109552267790SWillem de Bruijn 109652267790SWillem de Bruijn skb = sock_omalloc(sk, 0, GFP_KERNEL); 109752267790SWillem de Bruijn if (!skb) 109852267790SWillem de Bruijn return NULL; 109952267790SWillem de Bruijn 110052267790SWillem de Bruijn BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb)); 110152267790SWillem de Bruijn uarg = (void *)skb->cb; 1102a91dbff5SWillem de Bruijn uarg->mmp.user = NULL; 1103a91dbff5SWillem de Bruijn 1104a91dbff5SWillem de Bruijn if (mm_account_pinned_pages(&uarg->mmp, size)) { 1105a91dbff5SWillem de Bruijn kfree_skb(skb); 1106a91dbff5SWillem de Bruijn return NULL; 1107a91dbff5SWillem de Bruijn } 110852267790SWillem de Bruijn 110952267790SWillem de Bruijn uarg->callback = sock_zerocopy_callback; 11104ab6c99dSWillem de Bruijn uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1; 11114ab6c99dSWillem de Bruijn uarg->len = 1; 11124ab6c99dSWillem de Bruijn uarg->bytelen = size; 111352267790SWillem de Bruijn uarg->zerocopy = 1; 1114c1d1b437SEric Dumazet refcount_set(&uarg->refcnt, 1); 111552267790SWillem de Bruijn sock_hold(sk); 111652267790SWillem de Bruijn 111752267790SWillem de Bruijn return uarg; 111852267790SWillem de Bruijn } 111952267790SWillem de Bruijn EXPORT_SYMBOL_GPL(sock_zerocopy_alloc); 112052267790SWillem de Bruijn 112152267790SWillem de Bruijn static inline struct sk_buff *skb_from_uarg(struct ubuf_info *uarg) 112252267790SWillem de Bruijn { 112352267790SWillem de Bruijn return container_of((void *)uarg, struct sk_buff, cb); 112452267790SWillem de Bruijn } 112552267790SWillem de Bruijn 11264ab6c99dSWillem de Bruijn struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size, 11274ab6c99dSWillem de Bruijn struct ubuf_info *uarg) 11284ab6c99dSWillem de Bruijn { 11294ab6c99dSWillem de Bruijn if (uarg) { 11304ab6c99dSWillem de Bruijn const u32 byte_limit = 1 << 19; /* limit to a few TSO */ 11314ab6c99dSWillem de Bruijn u32 bytelen, next; 11324ab6c99dSWillem de Bruijn 11334ab6c99dSWillem de Bruijn /* realloc only when socket is locked (TCP, UDP cork), 11344ab6c99dSWillem de Bruijn * so uarg->len and sk_zckey access is serialized 11354ab6c99dSWillem de Bruijn */ 11364ab6c99dSWillem de Bruijn if (!sock_owned_by_user(sk)) { 11374ab6c99dSWillem de Bruijn WARN_ON_ONCE(1); 11384ab6c99dSWillem de Bruijn return NULL; 11394ab6c99dSWillem de Bruijn } 11404ab6c99dSWillem de Bruijn 11414ab6c99dSWillem de Bruijn bytelen = uarg->bytelen + size; 11424ab6c99dSWillem de Bruijn if (uarg->len == USHRT_MAX - 1 || bytelen > byte_limit) { 11434ab6c99dSWillem de Bruijn /* TCP can create new skb to attach new uarg */ 11444ab6c99dSWillem de Bruijn if (sk->sk_type == SOCK_STREAM) 11454ab6c99dSWillem de Bruijn goto new_alloc; 11464ab6c99dSWillem de Bruijn return NULL; 11474ab6c99dSWillem de Bruijn } 11484ab6c99dSWillem de Bruijn 11494ab6c99dSWillem de Bruijn next = (u32)atomic_read(&sk->sk_zckey); 11504ab6c99dSWillem de Bruijn if ((u32)(uarg->id + uarg->len) == next) { 1151a91dbff5SWillem de Bruijn if (mm_account_pinned_pages(&uarg->mmp, size)) 1152a91dbff5SWillem de Bruijn return NULL; 11534ab6c99dSWillem de Bruijn uarg->len++; 11544ab6c99dSWillem de Bruijn uarg->bytelen = bytelen; 11554ab6c99dSWillem de Bruijn atomic_set(&sk->sk_zckey, ++next); 1156100f6d8eSWillem de Bruijn 1157100f6d8eSWillem de Bruijn /* no extra ref when appending to datagram (MSG_MORE) */ 1158100f6d8eSWillem de Bruijn if (sk->sk_type == SOCK_STREAM) 1159db5bce32SEric Dumazet sock_zerocopy_get(uarg); 1160100f6d8eSWillem de Bruijn 11614ab6c99dSWillem de Bruijn return uarg; 11624ab6c99dSWillem de Bruijn } 11634ab6c99dSWillem de Bruijn } 11644ab6c99dSWillem de Bruijn 11654ab6c99dSWillem de Bruijn new_alloc: 11664ab6c99dSWillem de Bruijn return sock_zerocopy_alloc(sk, size); 11674ab6c99dSWillem de Bruijn } 11684ab6c99dSWillem de Bruijn EXPORT_SYMBOL_GPL(sock_zerocopy_realloc); 11694ab6c99dSWillem de Bruijn 11704ab6c99dSWillem de Bruijn static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len) 11714ab6c99dSWillem de Bruijn { 11724ab6c99dSWillem de Bruijn struct sock_exterr_skb *serr = SKB_EXT_ERR(skb); 11734ab6c99dSWillem de Bruijn u32 old_lo, old_hi; 11744ab6c99dSWillem de Bruijn u64 sum_len; 11754ab6c99dSWillem de Bruijn 11764ab6c99dSWillem de Bruijn old_lo = serr->ee.ee_info; 11774ab6c99dSWillem de Bruijn old_hi = serr->ee.ee_data; 11784ab6c99dSWillem de Bruijn sum_len = old_hi - old_lo + 1ULL + len; 11794ab6c99dSWillem de Bruijn 11804ab6c99dSWillem de Bruijn if (sum_len >= (1ULL << 32)) 11814ab6c99dSWillem de Bruijn return false; 11824ab6c99dSWillem de Bruijn 11834ab6c99dSWillem de Bruijn if (lo != old_hi + 1) 11844ab6c99dSWillem de Bruijn return false; 11854ab6c99dSWillem de Bruijn 11864ab6c99dSWillem de Bruijn serr->ee.ee_data += len; 11874ab6c99dSWillem de Bruijn return true; 11884ab6c99dSWillem de Bruijn } 11894ab6c99dSWillem de Bruijn 119052267790SWillem de Bruijn void sock_zerocopy_callback(struct ubuf_info *uarg, bool success) 119152267790SWillem de Bruijn { 11924ab6c99dSWillem de Bruijn struct sk_buff *tail, *skb = skb_from_uarg(uarg); 119352267790SWillem de Bruijn struct sock_exterr_skb *serr; 119452267790SWillem de Bruijn struct sock *sk = skb->sk; 11954ab6c99dSWillem de Bruijn struct sk_buff_head *q; 11964ab6c99dSWillem de Bruijn unsigned long flags; 11974ab6c99dSWillem de Bruijn u32 lo, hi; 11984ab6c99dSWillem de Bruijn u16 len; 119952267790SWillem de Bruijn 1200ccaffff1SWillem de Bruijn mm_unaccount_pinned_pages(&uarg->mmp); 1201ccaffff1SWillem de Bruijn 12024ab6c99dSWillem de Bruijn /* if !len, there was only 1 call, and it was aborted 12034ab6c99dSWillem de Bruijn * so do not queue a completion notification 12044ab6c99dSWillem de Bruijn */ 12054ab6c99dSWillem de Bruijn if (!uarg->len || sock_flag(sk, SOCK_DEAD)) 120652267790SWillem de Bruijn goto release; 120752267790SWillem de Bruijn 12084ab6c99dSWillem de Bruijn len = uarg->len; 12094ab6c99dSWillem de Bruijn lo = uarg->id; 12104ab6c99dSWillem de Bruijn hi = uarg->id + len - 1; 12114ab6c99dSWillem de Bruijn 121252267790SWillem de Bruijn serr = SKB_EXT_ERR(skb); 121352267790SWillem de Bruijn memset(serr, 0, sizeof(*serr)); 121452267790SWillem de Bruijn serr->ee.ee_errno = 0; 121552267790SWillem de Bruijn serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY; 12164ab6c99dSWillem de Bruijn serr->ee.ee_data = hi; 12174ab6c99dSWillem de Bruijn serr->ee.ee_info = lo; 121852267790SWillem de Bruijn if (!success) 121952267790SWillem de Bruijn serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED; 122052267790SWillem de Bruijn 12214ab6c99dSWillem de Bruijn q = &sk->sk_error_queue; 12224ab6c99dSWillem de Bruijn spin_lock_irqsave(&q->lock, flags); 12234ab6c99dSWillem de Bruijn tail = skb_peek_tail(q); 12244ab6c99dSWillem de Bruijn if (!tail || SKB_EXT_ERR(tail)->ee.ee_origin != SO_EE_ORIGIN_ZEROCOPY || 12254ab6c99dSWillem de Bruijn !skb_zerocopy_notify_extend(tail, lo, len)) { 12264ab6c99dSWillem de Bruijn __skb_queue_tail(q, skb); 122752267790SWillem de Bruijn skb = NULL; 12284ab6c99dSWillem de Bruijn } 12294ab6c99dSWillem de Bruijn spin_unlock_irqrestore(&q->lock, flags); 123052267790SWillem de Bruijn 123152267790SWillem de Bruijn sk->sk_error_report(sk); 123252267790SWillem de Bruijn 123352267790SWillem de Bruijn release: 123452267790SWillem de Bruijn consume_skb(skb); 123552267790SWillem de Bruijn sock_put(sk); 123652267790SWillem de Bruijn } 123752267790SWillem de Bruijn EXPORT_SYMBOL_GPL(sock_zerocopy_callback); 123852267790SWillem de Bruijn 123952267790SWillem de Bruijn void sock_zerocopy_put(struct ubuf_info *uarg) 124052267790SWillem de Bruijn { 1241c1d1b437SEric Dumazet if (uarg && refcount_dec_and_test(&uarg->refcnt)) { 124252267790SWillem de Bruijn if (uarg->callback) 124352267790SWillem de Bruijn uarg->callback(uarg, uarg->zerocopy); 124452267790SWillem de Bruijn else 124552267790SWillem de Bruijn consume_skb(skb_from_uarg(uarg)); 124652267790SWillem de Bruijn } 124752267790SWillem de Bruijn } 124852267790SWillem de Bruijn EXPORT_SYMBOL_GPL(sock_zerocopy_put); 124952267790SWillem de Bruijn 125052900d22SWillem de Bruijn void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref) 125152267790SWillem de Bruijn { 125252267790SWillem de Bruijn if (uarg) { 125352267790SWillem de Bruijn struct sock *sk = skb_from_uarg(uarg)->sk; 125452267790SWillem de Bruijn 125552267790SWillem de Bruijn atomic_dec(&sk->sk_zckey); 12564ab6c99dSWillem de Bruijn uarg->len--; 125752267790SWillem de Bruijn 125852900d22SWillem de Bruijn if (have_uref) 125952267790SWillem de Bruijn sock_zerocopy_put(uarg); 126052267790SWillem de Bruijn } 126152267790SWillem de Bruijn } 126252267790SWillem de Bruijn EXPORT_SYMBOL_GPL(sock_zerocopy_put_abort); 126352267790SWillem de Bruijn 1264b5947e5dSWillem de Bruijn int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len) 1265b5947e5dSWillem de Bruijn { 1266b5947e5dSWillem de Bruijn return __zerocopy_sg_from_iter(skb->sk, skb, &msg->msg_iter, len); 1267b5947e5dSWillem de Bruijn } 1268b5947e5dSWillem de Bruijn EXPORT_SYMBOL_GPL(skb_zerocopy_iter_dgram); 1269b5947e5dSWillem de Bruijn 127052267790SWillem de Bruijn int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb, 127152267790SWillem de Bruijn struct msghdr *msg, int len, 127252267790SWillem de Bruijn struct ubuf_info *uarg) 127352267790SWillem de Bruijn { 12744ab6c99dSWillem de Bruijn struct ubuf_info *orig_uarg = skb_zcopy(skb); 127552267790SWillem de Bruijn struct iov_iter orig_iter = msg->msg_iter; 127652267790SWillem de Bruijn int err, orig_len = skb->len; 127752267790SWillem de Bruijn 12784ab6c99dSWillem de Bruijn /* An skb can only point to one uarg. This edge case happens when 12794ab6c99dSWillem de Bruijn * TCP appends to an skb, but zerocopy_realloc triggered a new alloc. 12804ab6c99dSWillem de Bruijn */ 12814ab6c99dSWillem de Bruijn if (orig_uarg && uarg != orig_uarg) 12824ab6c99dSWillem de Bruijn return -EEXIST; 12834ab6c99dSWillem de Bruijn 128452267790SWillem de Bruijn err = __zerocopy_sg_from_iter(sk, skb, &msg->msg_iter, len); 128552267790SWillem de Bruijn if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) { 128654d43117SWillem de Bruijn struct sock *save_sk = skb->sk; 128754d43117SWillem de Bruijn 128852267790SWillem de Bruijn /* Streams do not free skb on error. Reset to prev state. */ 128952267790SWillem de Bruijn msg->msg_iter = orig_iter; 129054d43117SWillem de Bruijn skb->sk = sk; 129152267790SWillem de Bruijn ___pskb_trim(skb, orig_len); 129254d43117SWillem de Bruijn skb->sk = save_sk; 129352267790SWillem de Bruijn return err; 129452267790SWillem de Bruijn } 129552267790SWillem de Bruijn 129652900d22SWillem de Bruijn skb_zcopy_set(skb, uarg, NULL); 129752267790SWillem de Bruijn return skb->len - orig_len; 129852267790SWillem de Bruijn } 129952267790SWillem de Bruijn EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream); 130052267790SWillem de Bruijn 13011f8b977aSWillem de Bruijn static int skb_zerocopy_clone(struct sk_buff *nskb, struct sk_buff *orig, 130252267790SWillem de Bruijn gfp_t gfp_mask) 130352267790SWillem de Bruijn { 130452267790SWillem de Bruijn if (skb_zcopy(orig)) { 130552267790SWillem de Bruijn if (skb_zcopy(nskb)) { 130652267790SWillem de Bruijn /* !gfp_mask callers are verified to !skb_zcopy(nskb) */ 130752267790SWillem de Bruijn if (!gfp_mask) { 130852267790SWillem de Bruijn WARN_ON_ONCE(1); 130952267790SWillem de Bruijn return -ENOMEM; 131052267790SWillem de Bruijn } 131152267790SWillem de Bruijn if (skb_uarg(nskb) == skb_uarg(orig)) 131252267790SWillem de Bruijn return 0; 131352267790SWillem de Bruijn if (skb_copy_ubufs(nskb, GFP_ATOMIC)) 131452267790SWillem de Bruijn return -EIO; 131552267790SWillem de Bruijn } 131652900d22SWillem de Bruijn skb_zcopy_set(nskb, skb_uarg(orig), NULL); 131752267790SWillem de Bruijn } 131852267790SWillem de Bruijn return 0; 131952267790SWillem de Bruijn } 132052267790SWillem de Bruijn 13212c53040fSBen Hutchings /** 13222c53040fSBen Hutchings * skb_copy_ubufs - copy userspace skb frags buffers to kernel 132348c83012SMichael S. Tsirkin * @skb: the skb to modify 132448c83012SMichael S. Tsirkin * @gfp_mask: allocation priority 132548c83012SMichael S. Tsirkin * 132648c83012SMichael S. Tsirkin * This must be called on SKBTX_DEV_ZEROCOPY skb. 132748c83012SMichael S. Tsirkin * It will copy all frags into kernel and drop the reference 132848c83012SMichael S. Tsirkin * to userspace pages. 132948c83012SMichael S. Tsirkin * 133048c83012SMichael S. Tsirkin * If this function is called from an interrupt gfp_mask() must be 133148c83012SMichael S. Tsirkin * %GFP_ATOMIC. 133248c83012SMichael S. Tsirkin * 133348c83012SMichael S. Tsirkin * Returns 0 on success or a negative error code on failure 133448c83012SMichael S. Tsirkin * to allocate kernel memory to copy to. 133548c83012SMichael S. Tsirkin */ 133648c83012SMichael S. Tsirkin int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask) 1337a6686f2fSShirley Ma { 1338a6686f2fSShirley Ma int num_frags = skb_shinfo(skb)->nr_frags; 1339a6686f2fSShirley Ma struct page *page, *head = NULL; 13403ece7826SWillem de Bruijn int i, new_frags; 13413ece7826SWillem de Bruijn u32 d_off; 1342a6686f2fSShirley Ma 13433ece7826SWillem de Bruijn if (skb_shared(skb) || skb_unclone(skb, gfp_mask)) 13443ece7826SWillem de Bruijn return -EINVAL; 13453ece7826SWillem de Bruijn 1346f72c4ac6SWillem de Bruijn if (!num_frags) 1347f72c4ac6SWillem de Bruijn goto release; 1348f72c4ac6SWillem de Bruijn 13493ece7826SWillem de Bruijn new_frags = (__skb_pagelen(skb) + PAGE_SIZE - 1) >> PAGE_SHIFT; 13503ece7826SWillem de Bruijn for (i = 0; i < new_frags; i++) { 135102756ed4SKrishna Kumar page = alloc_page(gfp_mask); 1352a6686f2fSShirley Ma if (!page) { 1353a6686f2fSShirley Ma while (head) { 135440dadff2SSunghan Suh struct page *next = (struct page *)page_private(head); 1355a6686f2fSShirley Ma put_page(head); 1356a6686f2fSShirley Ma head = next; 1357a6686f2fSShirley Ma } 1358a6686f2fSShirley Ma return -ENOMEM; 1359a6686f2fSShirley Ma } 13603ece7826SWillem de Bruijn set_page_private(page, (unsigned long)head); 13613ece7826SWillem de Bruijn head = page; 13623ece7826SWillem de Bruijn } 13633ece7826SWillem de Bruijn 13643ece7826SWillem de Bruijn page = head; 13653ece7826SWillem de Bruijn d_off = 0; 13663ece7826SWillem de Bruijn for (i = 0; i < num_frags; i++) { 13673ece7826SWillem de Bruijn skb_frag_t *f = &skb_shinfo(skb)->frags[i]; 13683ece7826SWillem de Bruijn u32 p_off, p_len, copied; 13693ece7826SWillem de Bruijn struct page *p; 13703ece7826SWillem de Bruijn u8 *vaddr; 1371c613c209SWillem de Bruijn 1372b54c9d5bSJonathan Lemon skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f), 1373c613c209SWillem de Bruijn p, p_off, p_len, copied) { 13743ece7826SWillem de Bruijn u32 copy, done = 0; 1375c613c209SWillem de Bruijn vaddr = kmap_atomic(p); 13763ece7826SWillem de Bruijn 13773ece7826SWillem de Bruijn while (done < p_len) { 13783ece7826SWillem de Bruijn if (d_off == PAGE_SIZE) { 13793ece7826SWillem de Bruijn d_off = 0; 13803ece7826SWillem de Bruijn page = (struct page *)page_private(page); 13813ece7826SWillem de Bruijn } 13823ece7826SWillem de Bruijn copy = min_t(u32, PAGE_SIZE - d_off, p_len - done); 13833ece7826SWillem de Bruijn memcpy(page_address(page) + d_off, 13843ece7826SWillem de Bruijn vaddr + p_off + done, copy); 13853ece7826SWillem de Bruijn done += copy; 13863ece7826SWillem de Bruijn d_off += copy; 13873ece7826SWillem de Bruijn } 138851c56b00SEric Dumazet kunmap_atomic(vaddr); 1389c613c209SWillem de Bruijn } 1390a6686f2fSShirley Ma } 1391a6686f2fSShirley Ma 1392a6686f2fSShirley Ma /* skb frags release userspace buffers */ 139302756ed4SKrishna Kumar for (i = 0; i < num_frags; i++) 1394a8605c60SIan Campbell skb_frag_unref(skb, i); 1395a6686f2fSShirley Ma 1396a6686f2fSShirley Ma /* skb frags point to kernel buffers */ 13973ece7826SWillem de Bruijn for (i = 0; i < new_frags - 1; i++) { 13983ece7826SWillem de Bruijn __skb_fill_page_desc(skb, i, head, 0, PAGE_SIZE); 139940dadff2SSunghan Suh head = (struct page *)page_private(head); 1400a6686f2fSShirley Ma } 14013ece7826SWillem de Bruijn __skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off); 14023ece7826SWillem de Bruijn skb_shinfo(skb)->nr_frags = new_frags; 140348c83012SMichael S. Tsirkin 1404b90ddd56SWillem de Bruijn release: 14051f8b977aSWillem de Bruijn skb_zcopy_clear(skb, false); 1406a6686f2fSShirley Ma return 0; 1407a6686f2fSShirley Ma } 1408dcc0fb78SMichael S. Tsirkin EXPORT_SYMBOL_GPL(skb_copy_ubufs); 1409a6686f2fSShirley Ma 1410e0053ec0SHerbert Xu /** 1411e0053ec0SHerbert Xu * skb_clone - duplicate an sk_buff 1412e0053ec0SHerbert Xu * @skb: buffer to clone 1413e0053ec0SHerbert Xu * @gfp_mask: allocation priority 1414e0053ec0SHerbert Xu * 1415e0053ec0SHerbert Xu * Duplicate an &sk_buff. The new one is not owned by a socket. Both 1416e0053ec0SHerbert Xu * copies share the same packet data but not structure. The new 1417e0053ec0SHerbert Xu * buffer has a reference count of 1. If the allocation fails the 1418e0053ec0SHerbert Xu * function returns %NULL otherwise the new buffer is returned. 1419e0053ec0SHerbert Xu * 1420e0053ec0SHerbert Xu * If this function is called from an interrupt gfp_mask() must be 1421e0053ec0SHerbert Xu * %GFP_ATOMIC. 1422e0053ec0SHerbert Xu */ 1423e0053ec0SHerbert Xu 1424e0053ec0SHerbert Xu struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) 1425e0053ec0SHerbert Xu { 1426d0bf4a9eSEric Dumazet struct sk_buff_fclones *fclones = container_of(skb, 1427d0bf4a9eSEric Dumazet struct sk_buff_fclones, 1428d0bf4a9eSEric Dumazet skb1); 14296ffe75ebSEric Dumazet struct sk_buff *n; 1430e0053ec0SHerbert Xu 143170008aa5SMichael S. Tsirkin if (skb_orphan_frags(skb, gfp_mask)) 1432a6686f2fSShirley Ma return NULL; 1433a6686f2fSShirley Ma 1434e0053ec0SHerbert Xu if (skb->fclone == SKB_FCLONE_ORIG && 14352638595aSReshetova, Elena refcount_read(&fclones->fclone_ref) == 1) { 14366ffe75ebSEric Dumazet n = &fclones->skb2; 14372638595aSReshetova, Elena refcount_set(&fclones->fclone_ref, 2); 1438e0053ec0SHerbert Xu } else { 1439c93bdd0eSMel Gorman if (skb_pfmemalloc(skb)) 1440c93bdd0eSMel Gorman gfp_mask |= __GFP_MEMALLOC; 1441c93bdd0eSMel Gorman 1442e0053ec0SHerbert Xu n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); 1443e0053ec0SHerbert Xu if (!n) 1444e0053ec0SHerbert Xu return NULL; 1445fe55f6d5SVegard Nossum 1446e0053ec0SHerbert Xu n->fclone = SKB_FCLONE_UNAVAILABLE; 1447e0053ec0SHerbert Xu } 1448e0053ec0SHerbert Xu 1449e0053ec0SHerbert Xu return __skb_clone(n, skb); 14501da177e4SLinus Torvalds } 1451b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_clone); 14521da177e4SLinus Torvalds 1453b0768a86SToshiaki Makita void skb_headers_offset_update(struct sk_buff *skb, int off) 1454f5b17294SPravin B Shelar { 1455030737bcSEric Dumazet /* Only adjust this if it actually is csum_start rather than csum */ 1456030737bcSEric Dumazet if (skb->ip_summed == CHECKSUM_PARTIAL) 1457030737bcSEric Dumazet skb->csum_start += off; 1458f5b17294SPravin B Shelar /* {transport,network,mac}_header and tail are relative to skb->head */ 1459f5b17294SPravin B Shelar skb->transport_header += off; 1460f5b17294SPravin B Shelar skb->network_header += off; 1461f5b17294SPravin B Shelar if (skb_mac_header_was_set(skb)) 1462f5b17294SPravin B Shelar skb->mac_header += off; 1463f5b17294SPravin B Shelar skb->inner_transport_header += off; 1464f5b17294SPravin B Shelar skb->inner_network_header += off; 1465aefbd2b3SPravin B Shelar skb->inner_mac_header += off; 1466f5b17294SPravin B Shelar } 1467b0768a86SToshiaki Makita EXPORT_SYMBOL(skb_headers_offset_update); 1468f5b17294SPravin B Shelar 146908303c18SIlya Lesokhin void skb_copy_header(struct sk_buff *new, const struct sk_buff *old) 14701da177e4SLinus Torvalds { 1471dec18810SHerbert Xu __copy_skb_header(new, old); 1472dec18810SHerbert Xu 14737967168cSHerbert Xu skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; 14747967168cSHerbert Xu skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; 14757967168cSHerbert Xu skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; 14761da177e4SLinus Torvalds } 147708303c18SIlya Lesokhin EXPORT_SYMBOL(skb_copy_header); 14781da177e4SLinus Torvalds 1479c93bdd0eSMel Gorman static inline int skb_alloc_rx_flag(const struct sk_buff *skb) 1480c93bdd0eSMel Gorman { 1481c93bdd0eSMel Gorman if (skb_pfmemalloc(skb)) 1482c93bdd0eSMel Gorman return SKB_ALLOC_RX; 1483c93bdd0eSMel Gorman return 0; 1484c93bdd0eSMel Gorman } 1485c93bdd0eSMel Gorman 14861da177e4SLinus Torvalds /** 14871da177e4SLinus Torvalds * skb_copy - create private copy of an sk_buff 14881da177e4SLinus Torvalds * @skb: buffer to copy 14891da177e4SLinus Torvalds * @gfp_mask: allocation priority 14901da177e4SLinus Torvalds * 14911da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data. This is used when the 14921da177e4SLinus Torvalds * caller wishes to modify the data and needs a private copy of the 14931da177e4SLinus Torvalds * data to alter. Returns %NULL on failure or the pointer to the buffer 14941da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 14951da177e4SLinus Torvalds * 14961da177e4SLinus Torvalds * As by-product this function converts non-linear &sk_buff to linear 14971da177e4SLinus Torvalds * one, so that &sk_buff becomes completely private and caller is allowed 14981da177e4SLinus Torvalds * to modify all the data of returned buffer. This means that this 14991da177e4SLinus Torvalds * function is not recommended for use in circumstances when only 15001da177e4SLinus Torvalds * header is going to be modified. Use pskb_copy() instead. 15011da177e4SLinus Torvalds */ 15021da177e4SLinus Torvalds 1503dd0fc66fSAl Viro struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) 15041da177e4SLinus Torvalds { 15056602cebbSEric Dumazet int headerlen = skb_headroom(skb); 1506ec47ea82SAlexander Duyck unsigned int size = skb_end_offset(skb) + skb->data_len; 1507c93bdd0eSMel Gorman struct sk_buff *n = __alloc_skb(size, gfp_mask, 1508c93bdd0eSMel Gorman skb_alloc_rx_flag(skb), NUMA_NO_NODE); 15096602cebbSEric Dumazet 15101da177e4SLinus Torvalds if (!n) 15111da177e4SLinus Torvalds return NULL; 15121da177e4SLinus Torvalds 15131da177e4SLinus Torvalds /* Set the data pointer */ 15141da177e4SLinus Torvalds skb_reserve(n, headerlen); 15151da177e4SLinus Torvalds /* Set the tail pointer and length */ 15161da177e4SLinus Torvalds skb_put(n, skb->len); 15171da177e4SLinus Torvalds 15189f77fad3STim Hansen BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)); 15191da177e4SLinus Torvalds 152008303c18SIlya Lesokhin skb_copy_header(n, skb); 15211da177e4SLinus Torvalds return n; 15221da177e4SLinus Torvalds } 1523b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy); 15241da177e4SLinus Torvalds 15251da177e4SLinus Torvalds /** 1526bad93e9dSOctavian Purdila * __pskb_copy_fclone - create copy of an sk_buff with private head. 15271da177e4SLinus Torvalds * @skb: buffer to copy 1528117632e6SEric Dumazet * @headroom: headroom of new skb 15291da177e4SLinus Torvalds * @gfp_mask: allocation priority 1530bad93e9dSOctavian Purdila * @fclone: if true allocate the copy of the skb from the fclone 1531bad93e9dSOctavian Purdila * cache instead of the head cache; it is recommended to set this 1532bad93e9dSOctavian Purdila * to true for the cases where the copy will likely be cloned 15331da177e4SLinus Torvalds * 15341da177e4SLinus Torvalds * Make a copy of both an &sk_buff and part of its data, located 15351da177e4SLinus Torvalds * in header. Fragmented data remain shared. This is used when 15361da177e4SLinus Torvalds * the caller wishes to modify only header of &sk_buff and needs 15371da177e4SLinus Torvalds * private copy of the header to alter. Returns %NULL on failure 15381da177e4SLinus Torvalds * or the pointer to the buffer on success. 15391da177e4SLinus Torvalds * The returned buffer has a reference count of 1. 15401da177e4SLinus Torvalds */ 15411da177e4SLinus Torvalds 1542bad93e9dSOctavian Purdila struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom, 1543bad93e9dSOctavian Purdila gfp_t gfp_mask, bool fclone) 15441da177e4SLinus Torvalds { 1545117632e6SEric Dumazet unsigned int size = skb_headlen(skb) + headroom; 1546bad93e9dSOctavian Purdila int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0); 1547bad93e9dSOctavian Purdila struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE); 15486602cebbSEric Dumazet 15491da177e4SLinus Torvalds if (!n) 15501da177e4SLinus Torvalds goto out; 15511da177e4SLinus Torvalds 15521da177e4SLinus Torvalds /* Set the data pointer */ 1553117632e6SEric Dumazet skb_reserve(n, headroom); 15541da177e4SLinus Torvalds /* Set the tail pointer and length */ 15551da177e4SLinus Torvalds skb_put(n, skb_headlen(skb)); 15561da177e4SLinus Torvalds /* Copy the bytes */ 1557d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data(skb, n->data, n->len); 15581da177e4SLinus Torvalds 155925f484a6SHerbert Xu n->truesize += skb->data_len; 15601da177e4SLinus Torvalds n->data_len = skb->data_len; 15611da177e4SLinus Torvalds n->len = skb->len; 15621da177e4SLinus Torvalds 15631da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 15641da177e4SLinus Torvalds int i; 15651da177e4SLinus Torvalds 15661f8b977aSWillem de Bruijn if (skb_orphan_frags(skb, gfp_mask) || 15671f8b977aSWillem de Bruijn skb_zerocopy_clone(n, skb, gfp_mask)) { 15681511022cSDan Carpenter kfree_skb(n); 15691511022cSDan Carpenter n = NULL; 1570a6686f2fSShirley Ma goto out; 1571a6686f2fSShirley Ma } 15721da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 15731da177e4SLinus Torvalds skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; 1574ea2ab693SIan Campbell skb_frag_ref(skb, i); 15751da177e4SLinus Torvalds } 15761da177e4SLinus Torvalds skb_shinfo(n)->nr_frags = i; 15771da177e4SLinus Torvalds } 15781da177e4SLinus Torvalds 157921dc3301SDavid S. Miller if (skb_has_frag_list(skb)) { 15801da177e4SLinus Torvalds skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; 15811da177e4SLinus Torvalds skb_clone_fraglist(n); 15821da177e4SLinus Torvalds } 15831da177e4SLinus Torvalds 158408303c18SIlya Lesokhin skb_copy_header(n, skb); 15851da177e4SLinus Torvalds out: 15861da177e4SLinus Torvalds return n; 15871da177e4SLinus Torvalds } 1588bad93e9dSOctavian Purdila EXPORT_SYMBOL(__pskb_copy_fclone); 15891da177e4SLinus Torvalds 15901da177e4SLinus Torvalds /** 15911da177e4SLinus Torvalds * pskb_expand_head - reallocate header of &sk_buff 15921da177e4SLinus Torvalds * @skb: buffer to reallocate 15931da177e4SLinus Torvalds * @nhead: room to add at head 15941da177e4SLinus Torvalds * @ntail: room to add at tail 15951da177e4SLinus Torvalds * @gfp_mask: allocation priority 15961da177e4SLinus Torvalds * 1597bc32383cSMathias Krause * Expands (or creates identical copy, if @nhead and @ntail are zero) 1598bc32383cSMathias Krause * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have 15991da177e4SLinus Torvalds * reference count of 1. Returns zero in the case of success or error, 16001da177e4SLinus Torvalds * if expansion failed. In the last case, &sk_buff is not changed. 16011da177e4SLinus Torvalds * 16021da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 16031da177e4SLinus Torvalds * reloaded after call to this function. 16041da177e4SLinus Torvalds */ 16051da177e4SLinus Torvalds 160686a76cafSVictor Fusco int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, 1607dd0fc66fSAl Viro gfp_t gfp_mask) 16081da177e4SLinus Torvalds { 1609158f323bSEric Dumazet int i, osize = skb_end_offset(skb); 1610158f323bSEric Dumazet int size = osize + nhead + ntail; 16111da177e4SLinus Torvalds long off; 1612158f323bSEric Dumazet u8 *data; 16131da177e4SLinus Torvalds 16144edd87adSHerbert Xu BUG_ON(nhead < 0); 16154edd87adSHerbert Xu 16169f77fad3STim Hansen BUG_ON(skb_shared(skb)); 16171da177e4SLinus Torvalds 16181da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 16191da177e4SLinus Torvalds 1620c93bdd0eSMel Gorman if (skb_pfmemalloc(skb)) 1621c93bdd0eSMel Gorman gfp_mask |= __GFP_MEMALLOC; 1622c93bdd0eSMel Gorman data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), 1623c93bdd0eSMel Gorman gfp_mask, NUMA_NO_NODE, NULL); 16241da177e4SLinus Torvalds if (!data) 16251da177e4SLinus Torvalds goto nodata; 162687151b86SEric Dumazet size = SKB_WITH_OVERHEAD(ksize(data)); 16271da177e4SLinus Torvalds 16281da177e4SLinus Torvalds /* Copy only real data... and, alas, header. This should be 16296602cebbSEric Dumazet * optimized for the cases when header is void. 16306602cebbSEric Dumazet */ 16316602cebbSEric Dumazet memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head); 16326602cebbSEric Dumazet 16336602cebbSEric Dumazet memcpy((struct skb_shared_info *)(data + size), 16346602cebbSEric Dumazet skb_shinfo(skb), 1635fed66381SEric Dumazet offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags])); 16361da177e4SLinus Torvalds 16373e24591aSAlexander Duyck /* 16383e24591aSAlexander Duyck * if shinfo is shared we must drop the old head gracefully, but if it 16393e24591aSAlexander Duyck * is not we can just drop the old head and let the existing refcount 16403e24591aSAlexander Duyck * be since all we did is relocate the values 16413e24591aSAlexander Duyck */ 16423e24591aSAlexander Duyck if (skb_cloned(skb)) { 164370008aa5SMichael S. Tsirkin if (skb_orphan_frags(skb, gfp_mask)) 1644a6686f2fSShirley Ma goto nofrags; 16451f8b977aSWillem de Bruijn if (skb_zcopy(skb)) 1646c1d1b437SEric Dumazet refcount_inc(&skb_uarg(skb)->refcnt); 16471da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 1648ea2ab693SIan Campbell skb_frag_ref(skb, i); 16491da177e4SLinus Torvalds 165021dc3301SDavid S. Miller if (skb_has_frag_list(skb)) 16511da177e4SLinus Torvalds skb_clone_fraglist(skb); 16521da177e4SLinus Torvalds 16531da177e4SLinus Torvalds skb_release_data(skb); 16543e24591aSAlexander Duyck } else { 16553e24591aSAlexander Duyck skb_free_head(skb); 16561fd63041SEric Dumazet } 16571da177e4SLinus Torvalds off = (data + nhead) - skb->head; 16581da177e4SLinus Torvalds 16591da177e4SLinus Torvalds skb->head = data; 1660d3836f21SEric Dumazet skb->head_frag = 0; 16611da177e4SLinus Torvalds skb->data += off; 16624305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 16634305b541SArnaldo Carvalho de Melo skb->end = size; 166456eb8882SPatrick McHardy off = nhead; 16654305b541SArnaldo Carvalho de Melo #else 16664305b541SArnaldo Carvalho de Melo skb->end = skb->head + size; 166756eb8882SPatrick McHardy #endif 166827a884dcSArnaldo Carvalho de Melo skb->tail += off; 1669b41abb42SPeter Pan(潘卫平) skb_headers_offset_update(skb, nhead); 16701da177e4SLinus Torvalds skb->cloned = 0; 1671334a8132SPatrick McHardy skb->hdr_len = 0; 16721da177e4SLinus Torvalds skb->nohdr = 0; 16731da177e4SLinus Torvalds atomic_set(&skb_shinfo(skb)->dataref, 1); 1674158f323bSEric Dumazet 1675de8f3a83SDaniel Borkmann skb_metadata_clear(skb); 1676de8f3a83SDaniel Borkmann 1677158f323bSEric Dumazet /* It is not generally safe to change skb->truesize. 1678158f323bSEric Dumazet * For the moment, we really care of rx path, or 1679158f323bSEric Dumazet * when skb is orphaned (not attached to a socket). 1680158f323bSEric Dumazet */ 1681158f323bSEric Dumazet if (!skb->sk || skb->destructor == sock_edemux) 1682158f323bSEric Dumazet skb->truesize += size - osize; 1683158f323bSEric Dumazet 16841da177e4SLinus Torvalds return 0; 16851da177e4SLinus Torvalds 1686a6686f2fSShirley Ma nofrags: 1687a6686f2fSShirley Ma kfree(data); 16881da177e4SLinus Torvalds nodata: 16891da177e4SLinus Torvalds return -ENOMEM; 16901da177e4SLinus Torvalds } 1691b4ac530fSDavid S. Miller EXPORT_SYMBOL(pskb_expand_head); 16921da177e4SLinus Torvalds 16931da177e4SLinus Torvalds /* Make private copy of skb with writable head and some headroom */ 16941da177e4SLinus Torvalds 16951da177e4SLinus Torvalds struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) 16961da177e4SLinus Torvalds { 16971da177e4SLinus Torvalds struct sk_buff *skb2; 16981da177e4SLinus Torvalds int delta = headroom - skb_headroom(skb); 16991da177e4SLinus Torvalds 17001da177e4SLinus Torvalds if (delta <= 0) 17011da177e4SLinus Torvalds skb2 = pskb_copy(skb, GFP_ATOMIC); 17021da177e4SLinus Torvalds else { 17031da177e4SLinus Torvalds skb2 = skb_clone(skb, GFP_ATOMIC); 17041da177e4SLinus Torvalds if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, 17051da177e4SLinus Torvalds GFP_ATOMIC)) { 17061da177e4SLinus Torvalds kfree_skb(skb2); 17071da177e4SLinus Torvalds skb2 = NULL; 17081da177e4SLinus Torvalds } 17091da177e4SLinus Torvalds } 17101da177e4SLinus Torvalds return skb2; 17111da177e4SLinus Torvalds } 1712b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_realloc_headroom); 17131da177e4SLinus Torvalds 17141da177e4SLinus Torvalds /** 17151da177e4SLinus Torvalds * skb_copy_expand - copy and expand sk_buff 17161da177e4SLinus Torvalds * @skb: buffer to copy 17171da177e4SLinus Torvalds * @newheadroom: new free bytes at head 17181da177e4SLinus Torvalds * @newtailroom: new free bytes at tail 17191da177e4SLinus Torvalds * @gfp_mask: allocation priority 17201da177e4SLinus Torvalds * 17211da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data and while doing so 17221da177e4SLinus Torvalds * allocate additional space. 17231da177e4SLinus Torvalds * 17241da177e4SLinus Torvalds * This is used when the caller wishes to modify the data and needs a 17251da177e4SLinus Torvalds * private copy of the data to alter as well as more space for new fields. 17261da177e4SLinus Torvalds * Returns %NULL on failure or the pointer to the buffer 17271da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 17281da177e4SLinus Torvalds * 17291da177e4SLinus Torvalds * You must pass %GFP_ATOMIC as the allocation priority if this function 17301da177e4SLinus Torvalds * is called from an interrupt. 17311da177e4SLinus Torvalds */ 17321da177e4SLinus Torvalds struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 173386a76cafSVictor Fusco int newheadroom, int newtailroom, 1734dd0fc66fSAl Viro gfp_t gfp_mask) 17351da177e4SLinus Torvalds { 17361da177e4SLinus Torvalds /* 17371da177e4SLinus Torvalds * Allocate the copy buffer 17381da177e4SLinus Torvalds */ 1739c93bdd0eSMel Gorman struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom, 1740c93bdd0eSMel Gorman gfp_mask, skb_alloc_rx_flag(skb), 1741c93bdd0eSMel Gorman NUMA_NO_NODE); 1742efd1e8d5SPatrick McHardy int oldheadroom = skb_headroom(skb); 17431da177e4SLinus Torvalds int head_copy_len, head_copy_off; 17441da177e4SLinus Torvalds 17451da177e4SLinus Torvalds if (!n) 17461da177e4SLinus Torvalds return NULL; 17471da177e4SLinus Torvalds 17481da177e4SLinus Torvalds skb_reserve(n, newheadroom); 17491da177e4SLinus Torvalds 17501da177e4SLinus Torvalds /* Set the tail pointer and length */ 17511da177e4SLinus Torvalds skb_put(n, skb->len); 17521da177e4SLinus Torvalds 1753efd1e8d5SPatrick McHardy head_copy_len = oldheadroom; 17541da177e4SLinus Torvalds head_copy_off = 0; 17551da177e4SLinus Torvalds if (newheadroom <= head_copy_len) 17561da177e4SLinus Torvalds head_copy_len = newheadroom; 17571da177e4SLinus Torvalds else 17581da177e4SLinus Torvalds head_copy_off = newheadroom - head_copy_len; 17591da177e4SLinus Torvalds 17601da177e4SLinus Torvalds /* Copy the linear header and data. */ 17619f77fad3STim Hansen BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, 17629f77fad3STim Hansen skb->len + head_copy_len)); 17631da177e4SLinus Torvalds 176408303c18SIlya Lesokhin skb_copy_header(n, skb); 17651da177e4SLinus Torvalds 1766030737bcSEric Dumazet skb_headers_offset_update(n, newheadroom - oldheadroom); 1767efd1e8d5SPatrick McHardy 17681da177e4SLinus Torvalds return n; 17691da177e4SLinus Torvalds } 1770b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_expand); 17711da177e4SLinus Torvalds 17721da177e4SLinus Torvalds /** 1773cd0a137aSFlorian Fainelli * __skb_pad - zero pad the tail of an skb 17741da177e4SLinus Torvalds * @skb: buffer to pad 17751da177e4SLinus Torvalds * @pad: space to pad 1776cd0a137aSFlorian Fainelli * @free_on_error: free buffer on error 17771da177e4SLinus Torvalds * 17781da177e4SLinus Torvalds * Ensure that a buffer is followed by a padding area that is zero 17791da177e4SLinus Torvalds * filled. Used by network drivers which may DMA or transfer data 17801da177e4SLinus Torvalds * beyond the buffer end onto the wire. 17811da177e4SLinus Torvalds * 1782cd0a137aSFlorian Fainelli * May return error in out of memory cases. The skb is freed on error 1783cd0a137aSFlorian Fainelli * if @free_on_error is true. 17841da177e4SLinus Torvalds */ 17851da177e4SLinus Torvalds 1786cd0a137aSFlorian Fainelli int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error) 17871da177e4SLinus Torvalds { 17885b057c6bSHerbert Xu int err; 17895b057c6bSHerbert Xu int ntail; 17901da177e4SLinus Torvalds 17911da177e4SLinus Torvalds /* If the skbuff is non linear tailroom is always zero.. */ 17925b057c6bSHerbert Xu if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { 17931da177e4SLinus Torvalds memset(skb->data+skb->len, 0, pad); 17945b057c6bSHerbert Xu return 0; 17951da177e4SLinus Torvalds } 17961da177e4SLinus Torvalds 17974305b541SArnaldo Carvalho de Melo ntail = skb->data_len + pad - (skb->end - skb->tail); 17985b057c6bSHerbert Xu if (likely(skb_cloned(skb) || ntail > 0)) { 17995b057c6bSHerbert Xu err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); 18005b057c6bSHerbert Xu if (unlikely(err)) 18015b057c6bSHerbert Xu goto free_skb; 18025b057c6bSHerbert Xu } 18035b057c6bSHerbert Xu 18045b057c6bSHerbert Xu /* FIXME: The use of this function with non-linear skb's really needs 18055b057c6bSHerbert Xu * to be audited. 18065b057c6bSHerbert Xu */ 18075b057c6bSHerbert Xu err = skb_linearize(skb); 18085b057c6bSHerbert Xu if (unlikely(err)) 18095b057c6bSHerbert Xu goto free_skb; 18105b057c6bSHerbert Xu 18115b057c6bSHerbert Xu memset(skb->data + skb->len, 0, pad); 18125b057c6bSHerbert Xu return 0; 18135b057c6bSHerbert Xu 18145b057c6bSHerbert Xu free_skb: 1815cd0a137aSFlorian Fainelli if (free_on_error) 18161da177e4SLinus Torvalds kfree_skb(skb); 18175b057c6bSHerbert Xu return err; 18181da177e4SLinus Torvalds } 1819cd0a137aSFlorian Fainelli EXPORT_SYMBOL(__skb_pad); 18201da177e4SLinus Torvalds 18210dde3e16SIlpo Järvinen /** 18220c7ddf36SMathias Krause * pskb_put - add data to the tail of a potentially fragmented buffer 18230c7ddf36SMathias Krause * @skb: start of the buffer to use 18240c7ddf36SMathias Krause * @tail: tail fragment of the buffer to use 18250c7ddf36SMathias Krause * @len: amount of data to add 18260c7ddf36SMathias Krause * 18270c7ddf36SMathias Krause * This function extends the used data area of the potentially 18280c7ddf36SMathias Krause * fragmented buffer. @tail must be the last fragment of @skb -- or 18290c7ddf36SMathias Krause * @skb itself. If this would exceed the total buffer size the kernel 18300c7ddf36SMathias Krause * will panic. A pointer to the first byte of the extra data is 18310c7ddf36SMathias Krause * returned. 18320c7ddf36SMathias Krause */ 18330c7ddf36SMathias Krause 18344df864c1SJohannes Berg void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len) 18350c7ddf36SMathias Krause { 18360c7ddf36SMathias Krause if (tail != skb) { 18370c7ddf36SMathias Krause skb->data_len += len; 18380c7ddf36SMathias Krause skb->len += len; 18390c7ddf36SMathias Krause } 18400c7ddf36SMathias Krause return skb_put(tail, len); 18410c7ddf36SMathias Krause } 18420c7ddf36SMathias Krause EXPORT_SYMBOL_GPL(pskb_put); 18430c7ddf36SMathias Krause 18440c7ddf36SMathias Krause /** 18450dde3e16SIlpo Järvinen * skb_put - add data to a buffer 18460dde3e16SIlpo Järvinen * @skb: buffer to use 18470dde3e16SIlpo Järvinen * @len: amount of data to add 18480dde3e16SIlpo Järvinen * 18490dde3e16SIlpo Järvinen * This function extends the used data area of the buffer. If this would 18500dde3e16SIlpo Järvinen * exceed the total buffer size the kernel will panic. A pointer to the 18510dde3e16SIlpo Järvinen * first byte of the extra data is returned. 18520dde3e16SIlpo Järvinen */ 18534df864c1SJohannes Berg void *skb_put(struct sk_buff *skb, unsigned int len) 18540dde3e16SIlpo Järvinen { 18554df864c1SJohannes Berg void *tmp = skb_tail_pointer(skb); 18560dde3e16SIlpo Järvinen SKB_LINEAR_ASSERT(skb); 18570dde3e16SIlpo Järvinen skb->tail += len; 18580dde3e16SIlpo Järvinen skb->len += len; 18590dde3e16SIlpo Järvinen if (unlikely(skb->tail > skb->end)) 18600dde3e16SIlpo Järvinen skb_over_panic(skb, len, __builtin_return_address(0)); 18610dde3e16SIlpo Järvinen return tmp; 18620dde3e16SIlpo Järvinen } 18630dde3e16SIlpo Järvinen EXPORT_SYMBOL(skb_put); 18640dde3e16SIlpo Järvinen 18656be8ac2fSIlpo Järvinen /** 1866c2aa270aSIlpo Järvinen * skb_push - add data to the start of a buffer 1867c2aa270aSIlpo Järvinen * @skb: buffer to use 1868c2aa270aSIlpo Järvinen * @len: amount of data to add 1869c2aa270aSIlpo Järvinen * 1870c2aa270aSIlpo Järvinen * This function extends the used data area of the buffer at the buffer 1871c2aa270aSIlpo Järvinen * start. If this would exceed the total buffer headroom the kernel will 1872c2aa270aSIlpo Järvinen * panic. A pointer to the first byte of the extra data is returned. 1873c2aa270aSIlpo Järvinen */ 1874d58ff351SJohannes Berg void *skb_push(struct sk_buff *skb, unsigned int len) 1875c2aa270aSIlpo Järvinen { 1876c2aa270aSIlpo Järvinen skb->data -= len; 1877c2aa270aSIlpo Järvinen skb->len += len; 1878c2aa270aSIlpo Järvinen if (unlikely(skb->data < skb->head)) 1879c2aa270aSIlpo Järvinen skb_under_panic(skb, len, __builtin_return_address(0)); 1880c2aa270aSIlpo Järvinen return skb->data; 1881c2aa270aSIlpo Järvinen } 1882c2aa270aSIlpo Järvinen EXPORT_SYMBOL(skb_push); 1883c2aa270aSIlpo Järvinen 1884c2aa270aSIlpo Järvinen /** 18856be8ac2fSIlpo Järvinen * skb_pull - remove data from the start of a buffer 18866be8ac2fSIlpo Järvinen * @skb: buffer to use 18876be8ac2fSIlpo Järvinen * @len: amount of data to remove 18886be8ac2fSIlpo Järvinen * 18896be8ac2fSIlpo Järvinen * This function removes data from the start of a buffer, returning 18906be8ac2fSIlpo Järvinen * the memory to the headroom. A pointer to the next data in the buffer 18916be8ac2fSIlpo Järvinen * is returned. Once the data has been pulled future pushes will overwrite 18926be8ac2fSIlpo Järvinen * the old data. 18936be8ac2fSIlpo Järvinen */ 1894af72868bSJohannes Berg void *skb_pull(struct sk_buff *skb, unsigned int len) 18956be8ac2fSIlpo Järvinen { 189647d29646SDavid S. Miller return skb_pull_inline(skb, len); 18976be8ac2fSIlpo Järvinen } 18986be8ac2fSIlpo Järvinen EXPORT_SYMBOL(skb_pull); 18996be8ac2fSIlpo Järvinen 1900419ae74eSIlpo Järvinen /** 1901419ae74eSIlpo Järvinen * skb_trim - remove end from a buffer 1902419ae74eSIlpo Järvinen * @skb: buffer to alter 1903419ae74eSIlpo Järvinen * @len: new length 1904419ae74eSIlpo Järvinen * 1905419ae74eSIlpo Järvinen * Cut the length of a buffer down by removing data from the tail. If 1906419ae74eSIlpo Järvinen * the buffer is already under the length specified it is not modified. 1907419ae74eSIlpo Järvinen * The skb must be linear. 1908419ae74eSIlpo Järvinen */ 1909419ae74eSIlpo Järvinen void skb_trim(struct sk_buff *skb, unsigned int len) 1910419ae74eSIlpo Järvinen { 1911419ae74eSIlpo Järvinen if (skb->len > len) 1912419ae74eSIlpo Järvinen __skb_trim(skb, len); 1913419ae74eSIlpo Järvinen } 1914419ae74eSIlpo Järvinen EXPORT_SYMBOL(skb_trim); 1915419ae74eSIlpo Järvinen 19163cc0e873SHerbert Xu /* Trims skb to length len. It can change skb pointers. 19171da177e4SLinus Torvalds */ 19181da177e4SLinus Torvalds 19193cc0e873SHerbert Xu int ___pskb_trim(struct sk_buff *skb, unsigned int len) 19201da177e4SLinus Torvalds { 192127b437c8SHerbert Xu struct sk_buff **fragp; 192227b437c8SHerbert Xu struct sk_buff *frag; 19231da177e4SLinus Torvalds int offset = skb_headlen(skb); 19241da177e4SLinus Torvalds int nfrags = skb_shinfo(skb)->nr_frags; 19251da177e4SLinus Torvalds int i; 192627b437c8SHerbert Xu int err; 192727b437c8SHerbert Xu 192827b437c8SHerbert Xu if (skb_cloned(skb) && 192927b437c8SHerbert Xu unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) 193027b437c8SHerbert Xu return err; 19311da177e4SLinus Torvalds 1932f4d26fb3SHerbert Xu i = 0; 1933f4d26fb3SHerbert Xu if (offset >= len) 1934f4d26fb3SHerbert Xu goto drop_pages; 1935f4d26fb3SHerbert Xu 1936f4d26fb3SHerbert Xu for (; i < nfrags; i++) { 19379e903e08SEric Dumazet int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]); 193827b437c8SHerbert Xu 193927b437c8SHerbert Xu if (end < len) { 19401da177e4SLinus Torvalds offset = end; 194127b437c8SHerbert Xu continue; 19421da177e4SLinus Torvalds } 19431da177e4SLinus Torvalds 19449e903e08SEric Dumazet skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset); 194527b437c8SHerbert Xu 1946f4d26fb3SHerbert Xu drop_pages: 194727b437c8SHerbert Xu skb_shinfo(skb)->nr_frags = i; 194827b437c8SHerbert Xu 194927b437c8SHerbert Xu for (; i < nfrags; i++) 1950ea2ab693SIan Campbell skb_frag_unref(skb, i); 195127b437c8SHerbert Xu 195221dc3301SDavid S. Miller if (skb_has_frag_list(skb)) 195327b437c8SHerbert Xu skb_drop_fraglist(skb); 1954f4d26fb3SHerbert Xu goto done; 195527b437c8SHerbert Xu } 195627b437c8SHerbert Xu 195727b437c8SHerbert Xu for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); 195827b437c8SHerbert Xu fragp = &frag->next) { 195927b437c8SHerbert Xu int end = offset + frag->len; 196027b437c8SHerbert Xu 196127b437c8SHerbert Xu if (skb_shared(frag)) { 196227b437c8SHerbert Xu struct sk_buff *nfrag; 196327b437c8SHerbert Xu 196427b437c8SHerbert Xu nfrag = skb_clone(frag, GFP_ATOMIC); 196527b437c8SHerbert Xu if (unlikely(!nfrag)) 196627b437c8SHerbert Xu return -ENOMEM; 196727b437c8SHerbert Xu 196827b437c8SHerbert Xu nfrag->next = frag->next; 196985bb2a60SEric Dumazet consume_skb(frag); 197027b437c8SHerbert Xu frag = nfrag; 197127b437c8SHerbert Xu *fragp = frag; 197227b437c8SHerbert Xu } 197327b437c8SHerbert Xu 197427b437c8SHerbert Xu if (end < len) { 197527b437c8SHerbert Xu offset = end; 197627b437c8SHerbert Xu continue; 197727b437c8SHerbert Xu } 197827b437c8SHerbert Xu 197927b437c8SHerbert Xu if (end > len && 198027b437c8SHerbert Xu unlikely((err = pskb_trim(frag, len - offset)))) 198127b437c8SHerbert Xu return err; 198227b437c8SHerbert Xu 198327b437c8SHerbert Xu if (frag->next) 198427b437c8SHerbert Xu skb_drop_list(&frag->next); 198527b437c8SHerbert Xu break; 198627b437c8SHerbert Xu } 198727b437c8SHerbert Xu 1988f4d26fb3SHerbert Xu done: 198927b437c8SHerbert Xu if (len > skb_headlen(skb)) { 19901da177e4SLinus Torvalds skb->data_len -= skb->len - len; 19911da177e4SLinus Torvalds skb->len = len; 19921da177e4SLinus Torvalds } else { 19931da177e4SLinus Torvalds skb->len = len; 19941da177e4SLinus Torvalds skb->data_len = 0; 199527a884dcSArnaldo Carvalho de Melo skb_set_tail_pointer(skb, len); 19961da177e4SLinus Torvalds } 19971da177e4SLinus Torvalds 1998c21b48ccSEric Dumazet if (!skb->sk || skb->destructor == sock_edemux) 1999c21b48ccSEric Dumazet skb_condense(skb); 20001da177e4SLinus Torvalds return 0; 20011da177e4SLinus Torvalds } 2002b4ac530fSDavid S. Miller EXPORT_SYMBOL(___pskb_trim); 20031da177e4SLinus Torvalds 200488078d98SEric Dumazet /* Note : use pskb_trim_rcsum() instead of calling this directly 200588078d98SEric Dumazet */ 200688078d98SEric Dumazet int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len) 200788078d98SEric Dumazet { 200888078d98SEric Dumazet if (skb->ip_summed == CHECKSUM_COMPLETE) { 200988078d98SEric Dumazet int delta = skb->len - len; 201088078d98SEric Dumazet 2011d55bef50SDimitris Michailidis skb->csum = csum_block_sub(skb->csum, 2012d55bef50SDimitris Michailidis skb_checksum(skb, len, delta, 0), 2013d55bef50SDimitris Michailidis len); 201488078d98SEric Dumazet } 201588078d98SEric Dumazet return __pskb_trim(skb, len); 201688078d98SEric Dumazet } 201788078d98SEric Dumazet EXPORT_SYMBOL(pskb_trim_rcsum_slow); 201888078d98SEric Dumazet 20191da177e4SLinus Torvalds /** 20201da177e4SLinus Torvalds * __pskb_pull_tail - advance tail of skb header 20211da177e4SLinus Torvalds * @skb: buffer to reallocate 20221da177e4SLinus Torvalds * @delta: number of bytes to advance tail 20231da177e4SLinus Torvalds * 20241da177e4SLinus Torvalds * The function makes a sense only on a fragmented &sk_buff, 20251da177e4SLinus Torvalds * it expands header moving its tail forward and copying necessary 20261da177e4SLinus Torvalds * data from fragmented part. 20271da177e4SLinus Torvalds * 20281da177e4SLinus Torvalds * &sk_buff MUST have reference count of 1. 20291da177e4SLinus Torvalds * 20301da177e4SLinus Torvalds * Returns %NULL (and &sk_buff does not change) if pull failed 20311da177e4SLinus Torvalds * or value of new tail of skb in the case of success. 20321da177e4SLinus Torvalds * 20331da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 20341da177e4SLinus Torvalds * reloaded after call to this function. 20351da177e4SLinus Torvalds */ 20361da177e4SLinus Torvalds 20371da177e4SLinus Torvalds /* Moves tail of skb head forward, copying data from fragmented part, 20381da177e4SLinus Torvalds * when it is necessary. 20391da177e4SLinus Torvalds * 1. It may fail due to malloc failure. 20401da177e4SLinus Torvalds * 2. It may change skb pointers. 20411da177e4SLinus Torvalds * 20421da177e4SLinus Torvalds * It is pretty complicated. Luckily, it is called only in exceptional cases. 20431da177e4SLinus Torvalds */ 2044af72868bSJohannes Berg void *__pskb_pull_tail(struct sk_buff *skb, int delta) 20451da177e4SLinus Torvalds { 20461da177e4SLinus Torvalds /* If skb has not enough free space at tail, get new one 20471da177e4SLinus Torvalds * plus 128 bytes for future expansions. If we have enough 20481da177e4SLinus Torvalds * room at tail, reallocate without expansion only if skb is cloned. 20491da177e4SLinus Torvalds */ 20504305b541SArnaldo Carvalho de Melo int i, k, eat = (skb->tail + delta) - skb->end; 20511da177e4SLinus Torvalds 20521da177e4SLinus Torvalds if (eat > 0 || skb_cloned(skb)) { 20531da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, 20541da177e4SLinus Torvalds GFP_ATOMIC)) 20551da177e4SLinus Torvalds return NULL; 20561da177e4SLinus Torvalds } 20571da177e4SLinus Torvalds 20589f77fad3STim Hansen BUG_ON(skb_copy_bits(skb, skb_headlen(skb), 20599f77fad3STim Hansen skb_tail_pointer(skb), delta)); 20601da177e4SLinus Torvalds 20611da177e4SLinus Torvalds /* Optimization: no fragments, no reasons to preestimate 20621da177e4SLinus Torvalds * size of pulled pages. Superb. 20631da177e4SLinus Torvalds */ 206421dc3301SDavid S. Miller if (!skb_has_frag_list(skb)) 20651da177e4SLinus Torvalds goto pull_pages; 20661da177e4SLinus Torvalds 20671da177e4SLinus Torvalds /* Estimate size of pulled pages. */ 20681da177e4SLinus Torvalds eat = delta; 20691da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 20709e903e08SEric Dumazet int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); 20719e903e08SEric Dumazet 20729e903e08SEric Dumazet if (size >= eat) 20731da177e4SLinus Torvalds goto pull_pages; 20749e903e08SEric Dumazet eat -= size; 20751da177e4SLinus Torvalds } 20761da177e4SLinus Torvalds 20771da177e4SLinus Torvalds /* If we need update frag list, we are in troubles. 207809001b03SWenhua Shi * Certainly, it is possible to add an offset to skb data, 20791da177e4SLinus Torvalds * but taking into account that pulling is expected to 20801da177e4SLinus Torvalds * be very rare operation, it is worth to fight against 20811da177e4SLinus Torvalds * further bloating skb head and crucify ourselves here instead. 20821da177e4SLinus Torvalds * Pure masohism, indeed. 8)8) 20831da177e4SLinus Torvalds */ 20841da177e4SLinus Torvalds if (eat) { 20851da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 20861da177e4SLinus Torvalds struct sk_buff *clone = NULL; 20871da177e4SLinus Torvalds struct sk_buff *insp = NULL; 20881da177e4SLinus Torvalds 20891da177e4SLinus Torvalds do { 20901da177e4SLinus Torvalds if (list->len <= eat) { 20911da177e4SLinus Torvalds /* Eaten as whole. */ 20921da177e4SLinus Torvalds eat -= list->len; 20931da177e4SLinus Torvalds list = list->next; 20941da177e4SLinus Torvalds insp = list; 20951da177e4SLinus Torvalds } else { 20961da177e4SLinus Torvalds /* Eaten partially. */ 20971da177e4SLinus Torvalds 20981da177e4SLinus Torvalds if (skb_shared(list)) { 20991da177e4SLinus Torvalds /* Sucks! We need to fork list. :-( */ 21001da177e4SLinus Torvalds clone = skb_clone(list, GFP_ATOMIC); 21011da177e4SLinus Torvalds if (!clone) 21021da177e4SLinus Torvalds return NULL; 21031da177e4SLinus Torvalds insp = list->next; 21041da177e4SLinus Torvalds list = clone; 21051da177e4SLinus Torvalds } else { 21061da177e4SLinus Torvalds /* This may be pulled without 21071da177e4SLinus Torvalds * problems. */ 21081da177e4SLinus Torvalds insp = list; 21091da177e4SLinus Torvalds } 21101da177e4SLinus Torvalds if (!pskb_pull(list, eat)) { 21111da177e4SLinus Torvalds kfree_skb(clone); 21121da177e4SLinus Torvalds return NULL; 21131da177e4SLinus Torvalds } 21141da177e4SLinus Torvalds break; 21151da177e4SLinus Torvalds } 21161da177e4SLinus Torvalds } while (eat); 21171da177e4SLinus Torvalds 21181da177e4SLinus Torvalds /* Free pulled out fragments. */ 21191da177e4SLinus Torvalds while ((list = skb_shinfo(skb)->frag_list) != insp) { 21201da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = list->next; 21211da177e4SLinus Torvalds kfree_skb(list); 21221da177e4SLinus Torvalds } 21231da177e4SLinus Torvalds /* And insert new clone at head. */ 21241da177e4SLinus Torvalds if (clone) { 21251da177e4SLinus Torvalds clone->next = list; 21261da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = clone; 21271da177e4SLinus Torvalds } 21281da177e4SLinus Torvalds } 21291da177e4SLinus Torvalds /* Success! Now we may commit changes to skb data. */ 21301da177e4SLinus Torvalds 21311da177e4SLinus Torvalds pull_pages: 21321da177e4SLinus Torvalds eat = delta; 21331da177e4SLinus Torvalds k = 0; 21341da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 21359e903e08SEric Dumazet int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); 21369e903e08SEric Dumazet 21379e903e08SEric Dumazet if (size <= eat) { 2138ea2ab693SIan Campbell skb_frag_unref(skb, i); 21399e903e08SEric Dumazet eat -= size; 21401da177e4SLinus Torvalds } else { 2141b54c9d5bSJonathan Lemon skb_frag_t *frag = &skb_shinfo(skb)->frags[k]; 2142b54c9d5bSJonathan Lemon 2143b54c9d5bSJonathan Lemon *frag = skb_shinfo(skb)->frags[i]; 21441da177e4SLinus Torvalds if (eat) { 2145b54c9d5bSJonathan Lemon skb_frag_off_add(frag, eat); 2146b54c9d5bSJonathan Lemon skb_frag_size_sub(frag, eat); 21473ccc6c6fSlinzhang if (!i) 21483ccc6c6fSlinzhang goto end; 21491da177e4SLinus Torvalds eat = 0; 21501da177e4SLinus Torvalds } 21511da177e4SLinus Torvalds k++; 21521da177e4SLinus Torvalds } 21531da177e4SLinus Torvalds } 21541da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = k; 21551da177e4SLinus Torvalds 21563ccc6c6fSlinzhang end: 21571da177e4SLinus Torvalds skb->tail += delta; 21581da177e4SLinus Torvalds skb->data_len -= delta; 21591da177e4SLinus Torvalds 21601f8b977aSWillem de Bruijn if (!skb->data_len) 21611f8b977aSWillem de Bruijn skb_zcopy_clear(skb, false); 21621f8b977aSWillem de Bruijn 216327a884dcSArnaldo Carvalho de Melo return skb_tail_pointer(skb); 21641da177e4SLinus Torvalds } 2165b4ac530fSDavid S. Miller EXPORT_SYMBOL(__pskb_pull_tail); 21661da177e4SLinus Torvalds 216722019b17SEric Dumazet /** 216822019b17SEric Dumazet * skb_copy_bits - copy bits from skb to kernel buffer 216922019b17SEric Dumazet * @skb: source skb 217022019b17SEric Dumazet * @offset: offset in source 217122019b17SEric Dumazet * @to: destination buffer 217222019b17SEric Dumazet * @len: number of bytes to copy 217322019b17SEric Dumazet * 217422019b17SEric Dumazet * Copy the specified number of bytes from the source skb to the 217522019b17SEric Dumazet * destination buffer. 217622019b17SEric Dumazet * 217722019b17SEric Dumazet * CAUTION ! : 217822019b17SEric Dumazet * If its prototype is ever changed, 217922019b17SEric Dumazet * check arch/{*}/net/{*}.S files, 218022019b17SEric Dumazet * since it is called from BPF assembly code. 218122019b17SEric Dumazet */ 21821da177e4SLinus Torvalds int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) 21831da177e4SLinus Torvalds { 21841a028e50SDavid S. Miller int start = skb_headlen(skb); 2185fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 2186fbb398a8SDavid S. Miller int i, copy; 21871da177e4SLinus Torvalds 21881da177e4SLinus Torvalds if (offset > (int)skb->len - len) 21891da177e4SLinus Torvalds goto fault; 21901da177e4SLinus Torvalds 21911da177e4SLinus Torvalds /* Copy header. */ 21921a028e50SDavid S. Miller if ((copy = start - offset) > 0) { 21931da177e4SLinus Torvalds if (copy > len) 21941da177e4SLinus Torvalds copy = len; 2195d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, offset, to, copy); 21961da177e4SLinus Torvalds if ((len -= copy) == 0) 21971da177e4SLinus Torvalds return 0; 21981da177e4SLinus Torvalds offset += copy; 21991da177e4SLinus Torvalds to += copy; 22001da177e4SLinus Torvalds } 22011da177e4SLinus Torvalds 22021da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 22031a028e50SDavid S. Miller int end; 220451c56b00SEric Dumazet skb_frag_t *f = &skb_shinfo(skb)->frags[i]; 22051da177e4SLinus Torvalds 2206547b792cSIlpo Järvinen WARN_ON(start > offset + len); 22071a028e50SDavid S. Miller 220851c56b00SEric Dumazet end = start + skb_frag_size(f); 22091da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 2210c613c209SWillem de Bruijn u32 p_off, p_len, copied; 2211c613c209SWillem de Bruijn struct page *p; 22121da177e4SLinus Torvalds u8 *vaddr; 22131da177e4SLinus Torvalds 22141da177e4SLinus Torvalds if (copy > len) 22151da177e4SLinus Torvalds copy = len; 22161da177e4SLinus Torvalds 2217c613c209SWillem de Bruijn skb_frag_foreach_page(f, 2218b54c9d5bSJonathan Lemon skb_frag_off(f) + offset - start, 2219c613c209SWillem de Bruijn copy, p, p_off, p_len, copied) { 2220c613c209SWillem de Bruijn vaddr = kmap_atomic(p); 2221c613c209SWillem de Bruijn memcpy(to + copied, vaddr + p_off, p_len); 222251c56b00SEric Dumazet kunmap_atomic(vaddr); 2223c613c209SWillem de Bruijn } 22241da177e4SLinus Torvalds 22251da177e4SLinus Torvalds if ((len -= copy) == 0) 22261da177e4SLinus Torvalds return 0; 22271da177e4SLinus Torvalds offset += copy; 22281da177e4SLinus Torvalds to += copy; 22291da177e4SLinus Torvalds } 22301a028e50SDavid S. Miller start = end; 22311da177e4SLinus Torvalds } 22321da177e4SLinus Torvalds 2233fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 22341a028e50SDavid S. Miller int end; 22351da177e4SLinus Torvalds 2236547b792cSIlpo Järvinen WARN_ON(start > offset + len); 22371a028e50SDavid S. Miller 2238fbb398a8SDavid S. Miller end = start + frag_iter->len; 22391da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 22401da177e4SLinus Torvalds if (copy > len) 22411da177e4SLinus Torvalds copy = len; 2242fbb398a8SDavid S. Miller if (skb_copy_bits(frag_iter, offset - start, to, copy)) 22431da177e4SLinus Torvalds goto fault; 22441da177e4SLinus Torvalds if ((len -= copy) == 0) 22451da177e4SLinus Torvalds return 0; 22461da177e4SLinus Torvalds offset += copy; 22471da177e4SLinus Torvalds to += copy; 22481da177e4SLinus Torvalds } 22491a028e50SDavid S. Miller start = end; 22501da177e4SLinus Torvalds } 2251a6686f2fSShirley Ma 22521da177e4SLinus Torvalds if (!len) 22531da177e4SLinus Torvalds return 0; 22541da177e4SLinus Torvalds 22551da177e4SLinus Torvalds fault: 22561da177e4SLinus Torvalds return -EFAULT; 22571da177e4SLinus Torvalds } 2258b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_bits); 22591da177e4SLinus Torvalds 22609c55e01cSJens Axboe /* 22619c55e01cSJens Axboe * Callback from splice_to_pipe(), if we need to release some pages 22629c55e01cSJens Axboe * at the end of the spd in case we error'ed out in filling the pipe. 22639c55e01cSJens Axboe */ 22649c55e01cSJens Axboe static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) 22659c55e01cSJens Axboe { 22668b9d3728SJarek Poplawski put_page(spd->pages[i]); 22678b9d3728SJarek Poplawski } 22689c55e01cSJens Axboe 2269a108d5f3SDavid S. Miller static struct page *linear_to_page(struct page *page, unsigned int *len, 22704fb66994SJarek Poplawski unsigned int *offset, 227118aafc62SEric Dumazet struct sock *sk) 22728b9d3728SJarek Poplawski { 22735640f768SEric Dumazet struct page_frag *pfrag = sk_page_frag(sk); 22748b9d3728SJarek Poplawski 22755640f768SEric Dumazet if (!sk_page_frag_refill(sk, pfrag)) 22768b9d3728SJarek Poplawski return NULL; 22774fb66994SJarek Poplawski 22785640f768SEric Dumazet *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset); 22794fb66994SJarek Poplawski 22805640f768SEric Dumazet memcpy(page_address(pfrag->page) + pfrag->offset, 22815640f768SEric Dumazet page_address(page) + *offset, *len); 22825640f768SEric Dumazet *offset = pfrag->offset; 22835640f768SEric Dumazet pfrag->offset += *len; 22844fb66994SJarek Poplawski 22855640f768SEric Dumazet return pfrag->page; 22869c55e01cSJens Axboe } 22879c55e01cSJens Axboe 228841c73a0dSEric Dumazet static bool spd_can_coalesce(const struct splice_pipe_desc *spd, 228941c73a0dSEric Dumazet struct page *page, 229041c73a0dSEric Dumazet unsigned int offset) 229141c73a0dSEric Dumazet { 229241c73a0dSEric Dumazet return spd->nr_pages && 229341c73a0dSEric Dumazet spd->pages[spd->nr_pages - 1] == page && 229441c73a0dSEric Dumazet (spd->partial[spd->nr_pages - 1].offset + 229541c73a0dSEric Dumazet spd->partial[spd->nr_pages - 1].len == offset); 229641c73a0dSEric Dumazet } 229741c73a0dSEric Dumazet 22989c55e01cSJens Axboe /* 22999c55e01cSJens Axboe * Fill page/offset/length into spd, if it can hold more pages. 23009c55e01cSJens Axboe */ 2301a108d5f3SDavid S. Miller static bool spd_fill_page(struct splice_pipe_desc *spd, 230235f3d14dSJens Axboe struct pipe_inode_info *pipe, struct page *page, 23034fb66994SJarek Poplawski unsigned int *len, unsigned int offset, 230418aafc62SEric Dumazet bool linear, 23057a67e56fSJarek Poplawski struct sock *sk) 23069c55e01cSJens Axboe { 230741c73a0dSEric Dumazet if (unlikely(spd->nr_pages == MAX_SKB_FRAGS)) 2308a108d5f3SDavid S. Miller return true; 23099c55e01cSJens Axboe 23108b9d3728SJarek Poplawski if (linear) { 231118aafc62SEric Dumazet page = linear_to_page(page, len, &offset, sk); 23128b9d3728SJarek Poplawski if (!page) 2313a108d5f3SDavid S. Miller return true; 231441c73a0dSEric Dumazet } 231541c73a0dSEric Dumazet if (spd_can_coalesce(spd, page, offset)) { 231641c73a0dSEric Dumazet spd->partial[spd->nr_pages - 1].len += *len; 2317a108d5f3SDavid S. Miller return false; 231841c73a0dSEric Dumazet } 23198b9d3728SJarek Poplawski get_page(page); 23209c55e01cSJens Axboe spd->pages[spd->nr_pages] = page; 23214fb66994SJarek Poplawski spd->partial[spd->nr_pages].len = *len; 23229c55e01cSJens Axboe spd->partial[spd->nr_pages].offset = offset; 23239c55e01cSJens Axboe spd->nr_pages++; 23248b9d3728SJarek Poplawski 2325a108d5f3SDavid S. Miller return false; 23269c55e01cSJens Axboe } 23279c55e01cSJens Axboe 2328a108d5f3SDavid S. Miller static bool __splice_segment(struct page *page, unsigned int poff, 23292870c43dSOctavian Purdila unsigned int plen, unsigned int *off, 233018aafc62SEric Dumazet unsigned int *len, 2331d7ccf7c0SEric Dumazet struct splice_pipe_desc *spd, bool linear, 233235f3d14dSJens Axboe struct sock *sk, 233335f3d14dSJens Axboe struct pipe_inode_info *pipe) 23349c55e01cSJens Axboe { 23352870c43dSOctavian Purdila if (!*len) 2336a108d5f3SDavid S. Miller return true; 23379c55e01cSJens Axboe 23382870c43dSOctavian Purdila /* skip this segment if already processed */ 23392870c43dSOctavian Purdila if (*off >= plen) { 23402870c43dSOctavian Purdila *off -= plen; 2341a108d5f3SDavid S. Miller return false; 23422870c43dSOctavian Purdila } 23432870c43dSOctavian Purdila 23442870c43dSOctavian Purdila /* ignore any bits we already processed */ 23459ca1b22dSEric Dumazet poff += *off; 23469ca1b22dSEric Dumazet plen -= *off; 23472870c43dSOctavian Purdila *off = 0; 23482870c43dSOctavian Purdila 234918aafc62SEric Dumazet do { 235018aafc62SEric Dumazet unsigned int flen = min(*len, plen); 23512870c43dSOctavian Purdila 235218aafc62SEric Dumazet if (spd_fill_page(spd, pipe, page, &flen, poff, 235318aafc62SEric Dumazet linear, sk)) 2354a108d5f3SDavid S. Miller return true; 235518aafc62SEric Dumazet poff += flen; 235618aafc62SEric Dumazet plen -= flen; 23572870c43dSOctavian Purdila *len -= flen; 235818aafc62SEric Dumazet } while (*len && plen); 23592870c43dSOctavian Purdila 2360a108d5f3SDavid S. Miller return false; 2361db43a282SOctavian Purdila } 23629c55e01cSJens Axboe 23639c55e01cSJens Axboe /* 2364a108d5f3SDavid S. Miller * Map linear and fragment data from the skb to spd. It reports true if the 23652870c43dSOctavian Purdila * pipe is full or if we already spliced the requested length. 23669c55e01cSJens Axboe */ 2367a108d5f3SDavid S. Miller static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, 236835f3d14dSJens Axboe unsigned int *offset, unsigned int *len, 236935f3d14dSJens Axboe struct splice_pipe_desc *spd, struct sock *sk) 23702870c43dSOctavian Purdila { 23712870c43dSOctavian Purdila int seg; 2372fa9835e5STom Herbert struct sk_buff *iter; 23739c55e01cSJens Axboe 23741d0c0b32SEric Dumazet /* map the linear part : 23752996d31fSAlexander Duyck * If skb->head_frag is set, this 'linear' part is backed by a 23762996d31fSAlexander Duyck * fragment, and if the head is not shared with any clones then 23772996d31fSAlexander Duyck * we can avoid a copy since we own the head portion of this page. 23789c55e01cSJens Axboe */ 23792870c43dSOctavian Purdila if (__splice_segment(virt_to_page(skb->data), 23802870c43dSOctavian Purdila (unsigned long) skb->data & (PAGE_SIZE - 1), 23812870c43dSOctavian Purdila skb_headlen(skb), 238218aafc62SEric Dumazet offset, len, spd, 23833a7c1ee4SAlexander Duyck skb_head_is_locked(skb), 23841d0c0b32SEric Dumazet sk, pipe)) 2385a108d5f3SDavid S. Miller return true; 23869c55e01cSJens Axboe 23879c55e01cSJens Axboe /* 23889c55e01cSJens Axboe * then map the fragments 23899c55e01cSJens Axboe */ 23909c55e01cSJens Axboe for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { 23919c55e01cSJens Axboe const skb_frag_t *f = &skb_shinfo(skb)->frags[seg]; 23929c55e01cSJens Axboe 2393ea2ab693SIan Campbell if (__splice_segment(skb_frag_page(f), 2394b54c9d5bSJonathan Lemon skb_frag_off(f), skb_frag_size(f), 239518aafc62SEric Dumazet offset, len, spd, false, sk, pipe)) 2396a108d5f3SDavid S. Miller return true; 23979c55e01cSJens Axboe } 23989c55e01cSJens Axboe 2399fa9835e5STom Herbert skb_walk_frags(skb, iter) { 2400fa9835e5STom Herbert if (*offset >= iter->len) { 2401fa9835e5STom Herbert *offset -= iter->len; 2402fa9835e5STom Herbert continue; 2403fa9835e5STom Herbert } 2404fa9835e5STom Herbert /* __skb_splice_bits() only fails if the output has no room 2405fa9835e5STom Herbert * left, so no point in going over the frag_list for the error 2406fa9835e5STom Herbert * case. 2407fa9835e5STom Herbert */ 2408fa9835e5STom Herbert if (__skb_splice_bits(iter, pipe, offset, len, spd, sk)) 2409fa9835e5STom Herbert return true; 2410fa9835e5STom Herbert } 2411fa9835e5STom Herbert 2412a108d5f3SDavid S. Miller return false; 24139c55e01cSJens Axboe } 24149c55e01cSJens Axboe 24159c55e01cSJens Axboe /* 24169c55e01cSJens Axboe * Map data from the skb to a pipe. Should handle both the linear part, 2417fa9835e5STom Herbert * the fragments, and the frag list. 24189c55e01cSJens Axboe */ 2419a60e3cc7SHannes Frederic Sowa int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset, 24209c55e01cSJens Axboe struct pipe_inode_info *pipe, unsigned int tlen, 242125869262SAl Viro unsigned int flags) 24229c55e01cSJens Axboe { 242341c73a0dSEric Dumazet struct partial_page partial[MAX_SKB_FRAGS]; 242441c73a0dSEric Dumazet struct page *pages[MAX_SKB_FRAGS]; 24259c55e01cSJens Axboe struct splice_pipe_desc spd = { 24269c55e01cSJens Axboe .pages = pages, 24279c55e01cSJens Axboe .partial = partial, 2428047fe360SEric Dumazet .nr_pages_max = MAX_SKB_FRAGS, 242928a625cbSMiklos Szeredi .ops = &nosteal_pipe_buf_ops, 24309c55e01cSJens Axboe .spd_release = sock_spd_release, 24319c55e01cSJens Axboe }; 243235f3d14dSJens Axboe int ret = 0; 243335f3d14dSJens Axboe 2434fa9835e5STom Herbert __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk); 24359c55e01cSJens Axboe 2436a60e3cc7SHannes Frederic Sowa if (spd.nr_pages) 243725869262SAl Viro ret = splice_to_pipe(pipe, &spd); 24389c55e01cSJens Axboe 243935f3d14dSJens Axboe return ret; 24409c55e01cSJens Axboe } 24412b514574SHannes Frederic Sowa EXPORT_SYMBOL_GPL(skb_splice_bits); 24429c55e01cSJens Axboe 244320bf50deSTom Herbert /* Send skb data on a socket. Socket must be locked. */ 244420bf50deSTom Herbert int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset, 244520bf50deSTom Herbert int len) 244620bf50deSTom Herbert { 244720bf50deSTom Herbert unsigned int orig_len = len; 244820bf50deSTom Herbert struct sk_buff *head = skb; 244920bf50deSTom Herbert unsigned short fragidx; 245020bf50deSTom Herbert int slen, ret; 245120bf50deSTom Herbert 245220bf50deSTom Herbert do_frag_list: 245320bf50deSTom Herbert 245420bf50deSTom Herbert /* Deal with head data */ 245520bf50deSTom Herbert while (offset < skb_headlen(skb) && len) { 245620bf50deSTom Herbert struct kvec kv; 245720bf50deSTom Herbert struct msghdr msg; 245820bf50deSTom Herbert 245920bf50deSTom Herbert slen = min_t(int, len, skb_headlen(skb) - offset); 246020bf50deSTom Herbert kv.iov_base = skb->data + offset; 2461db5980d8SJohn Fastabend kv.iov_len = slen; 246220bf50deSTom Herbert memset(&msg, 0, sizeof(msg)); 2463bd95e678SJohn Fastabend msg.msg_flags = MSG_DONTWAIT; 246420bf50deSTom Herbert 246520bf50deSTom Herbert ret = kernel_sendmsg_locked(sk, &msg, &kv, 1, slen); 246620bf50deSTom Herbert if (ret <= 0) 246720bf50deSTom Herbert goto error; 246820bf50deSTom Herbert 246920bf50deSTom Herbert offset += ret; 247020bf50deSTom Herbert len -= ret; 247120bf50deSTom Herbert } 247220bf50deSTom Herbert 247320bf50deSTom Herbert /* All the data was skb head? */ 247420bf50deSTom Herbert if (!len) 247520bf50deSTom Herbert goto out; 247620bf50deSTom Herbert 247720bf50deSTom Herbert /* Make offset relative to start of frags */ 247820bf50deSTom Herbert offset -= skb_headlen(skb); 247920bf50deSTom Herbert 248020bf50deSTom Herbert /* Find where we are in frag list */ 248120bf50deSTom Herbert for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) { 248220bf50deSTom Herbert skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx]; 248320bf50deSTom Herbert 2484d8e18a51SMatthew Wilcox (Oracle) if (offset < skb_frag_size(frag)) 248520bf50deSTom Herbert break; 248620bf50deSTom Herbert 2487d8e18a51SMatthew Wilcox (Oracle) offset -= skb_frag_size(frag); 248820bf50deSTom Herbert } 248920bf50deSTom Herbert 249020bf50deSTom Herbert for (; len && fragidx < skb_shinfo(skb)->nr_frags; fragidx++) { 249120bf50deSTom Herbert skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx]; 249220bf50deSTom Herbert 2493d8e18a51SMatthew Wilcox (Oracle) slen = min_t(size_t, len, skb_frag_size(frag) - offset); 249420bf50deSTom Herbert 249520bf50deSTom Herbert while (slen) { 2496d8e18a51SMatthew Wilcox (Oracle) ret = kernel_sendpage_locked(sk, skb_frag_page(frag), 2497b54c9d5bSJonathan Lemon skb_frag_off(frag) + offset, 249820bf50deSTom Herbert slen, MSG_DONTWAIT); 249920bf50deSTom Herbert if (ret <= 0) 250020bf50deSTom Herbert goto error; 250120bf50deSTom Herbert 250220bf50deSTom Herbert len -= ret; 250320bf50deSTom Herbert offset += ret; 250420bf50deSTom Herbert slen -= ret; 250520bf50deSTom Herbert } 250620bf50deSTom Herbert 250720bf50deSTom Herbert offset = 0; 250820bf50deSTom Herbert } 250920bf50deSTom Herbert 251020bf50deSTom Herbert if (len) { 251120bf50deSTom Herbert /* Process any frag lists */ 251220bf50deSTom Herbert 251320bf50deSTom Herbert if (skb == head) { 251420bf50deSTom Herbert if (skb_has_frag_list(skb)) { 251520bf50deSTom Herbert skb = skb_shinfo(skb)->frag_list; 251620bf50deSTom Herbert goto do_frag_list; 251720bf50deSTom Herbert } 251820bf50deSTom Herbert } else if (skb->next) { 251920bf50deSTom Herbert skb = skb->next; 252020bf50deSTom Herbert goto do_frag_list; 252120bf50deSTom Herbert } 252220bf50deSTom Herbert } 252320bf50deSTom Herbert 252420bf50deSTom Herbert out: 252520bf50deSTom Herbert return orig_len - len; 252620bf50deSTom Herbert 252720bf50deSTom Herbert error: 252820bf50deSTom Herbert return orig_len == len ? ret : orig_len - len; 252920bf50deSTom Herbert } 253020bf50deSTom Herbert EXPORT_SYMBOL_GPL(skb_send_sock_locked); 253120bf50deSTom Herbert 2532357b40a1SHerbert Xu /** 2533357b40a1SHerbert Xu * skb_store_bits - store bits from kernel buffer to skb 2534357b40a1SHerbert Xu * @skb: destination buffer 2535357b40a1SHerbert Xu * @offset: offset in destination 2536357b40a1SHerbert Xu * @from: source buffer 2537357b40a1SHerbert Xu * @len: number of bytes to copy 2538357b40a1SHerbert Xu * 2539357b40a1SHerbert Xu * Copy the specified number of bytes from the source buffer to the 2540357b40a1SHerbert Xu * destination skb. This function handles all the messy bits of 2541357b40a1SHerbert Xu * traversing fragment lists and such. 2542357b40a1SHerbert Xu */ 2543357b40a1SHerbert Xu 25440c6fcc8aSStephen Hemminger int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len) 2545357b40a1SHerbert Xu { 25461a028e50SDavid S. Miller int start = skb_headlen(skb); 2547fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 2548fbb398a8SDavid S. Miller int i, copy; 2549357b40a1SHerbert Xu 2550357b40a1SHerbert Xu if (offset > (int)skb->len - len) 2551357b40a1SHerbert Xu goto fault; 2552357b40a1SHerbert Xu 25531a028e50SDavid S. Miller if ((copy = start - offset) > 0) { 2554357b40a1SHerbert Xu if (copy > len) 2555357b40a1SHerbert Xu copy = len; 255627d7ff46SArnaldo Carvalho de Melo skb_copy_to_linear_data_offset(skb, offset, from, copy); 2557357b40a1SHerbert Xu if ((len -= copy) == 0) 2558357b40a1SHerbert Xu return 0; 2559357b40a1SHerbert Xu offset += copy; 2560357b40a1SHerbert Xu from += copy; 2561357b40a1SHerbert Xu } 2562357b40a1SHerbert Xu 2563357b40a1SHerbert Xu for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 2564357b40a1SHerbert Xu skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 25651a028e50SDavid S. Miller int end; 2566357b40a1SHerbert Xu 2567547b792cSIlpo Järvinen WARN_ON(start > offset + len); 25681a028e50SDavid S. Miller 25699e903e08SEric Dumazet end = start + skb_frag_size(frag); 2570357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 2571c613c209SWillem de Bruijn u32 p_off, p_len, copied; 2572c613c209SWillem de Bruijn struct page *p; 2573357b40a1SHerbert Xu u8 *vaddr; 2574357b40a1SHerbert Xu 2575357b40a1SHerbert Xu if (copy > len) 2576357b40a1SHerbert Xu copy = len; 2577357b40a1SHerbert Xu 2578c613c209SWillem de Bruijn skb_frag_foreach_page(frag, 2579b54c9d5bSJonathan Lemon skb_frag_off(frag) + offset - start, 2580c613c209SWillem de Bruijn copy, p, p_off, p_len, copied) { 2581c613c209SWillem de Bruijn vaddr = kmap_atomic(p); 2582c613c209SWillem de Bruijn memcpy(vaddr + p_off, from + copied, p_len); 258351c56b00SEric Dumazet kunmap_atomic(vaddr); 2584c613c209SWillem de Bruijn } 2585357b40a1SHerbert Xu 2586357b40a1SHerbert Xu if ((len -= copy) == 0) 2587357b40a1SHerbert Xu return 0; 2588357b40a1SHerbert Xu offset += copy; 2589357b40a1SHerbert Xu from += copy; 2590357b40a1SHerbert Xu } 25911a028e50SDavid S. Miller start = end; 2592357b40a1SHerbert Xu } 2593357b40a1SHerbert Xu 2594fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 25951a028e50SDavid S. Miller int end; 2596357b40a1SHerbert Xu 2597547b792cSIlpo Järvinen WARN_ON(start > offset + len); 25981a028e50SDavid S. Miller 2599fbb398a8SDavid S. Miller end = start + frag_iter->len; 2600357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 2601357b40a1SHerbert Xu if (copy > len) 2602357b40a1SHerbert Xu copy = len; 2603fbb398a8SDavid S. Miller if (skb_store_bits(frag_iter, offset - start, 26041a028e50SDavid S. Miller from, copy)) 2605357b40a1SHerbert Xu goto fault; 2606357b40a1SHerbert Xu if ((len -= copy) == 0) 2607357b40a1SHerbert Xu return 0; 2608357b40a1SHerbert Xu offset += copy; 2609357b40a1SHerbert Xu from += copy; 2610357b40a1SHerbert Xu } 26111a028e50SDavid S. Miller start = end; 2612357b40a1SHerbert Xu } 2613357b40a1SHerbert Xu if (!len) 2614357b40a1SHerbert Xu return 0; 2615357b40a1SHerbert Xu 2616357b40a1SHerbert Xu fault: 2617357b40a1SHerbert Xu return -EFAULT; 2618357b40a1SHerbert Xu } 2619357b40a1SHerbert Xu EXPORT_SYMBOL(skb_store_bits); 2620357b40a1SHerbert Xu 26211da177e4SLinus Torvalds /* Checksum skb data. */ 26222817a336SDaniel Borkmann __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len, 26232817a336SDaniel Borkmann __wsum csum, const struct skb_checksum_ops *ops) 26241da177e4SLinus Torvalds { 26251a028e50SDavid S. Miller int start = skb_headlen(skb); 26261a028e50SDavid S. Miller int i, copy = start - offset; 2627fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 26281da177e4SLinus Torvalds int pos = 0; 26291da177e4SLinus Torvalds 26301da177e4SLinus Torvalds /* Checksum header. */ 26311da177e4SLinus Torvalds if (copy > 0) { 26321da177e4SLinus Torvalds if (copy > len) 26331da177e4SLinus Torvalds copy = len; 26342544af03SMatteo Croce csum = INDIRECT_CALL_1(ops->update, csum_partial_ext, 26352544af03SMatteo Croce skb->data + offset, copy, csum); 26361da177e4SLinus Torvalds if ((len -= copy) == 0) 26371da177e4SLinus Torvalds return csum; 26381da177e4SLinus Torvalds offset += copy; 26391da177e4SLinus Torvalds pos = copy; 26401da177e4SLinus Torvalds } 26411da177e4SLinus Torvalds 26421da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 26431a028e50SDavid S. Miller int end; 264451c56b00SEric Dumazet skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 26451da177e4SLinus Torvalds 2646547b792cSIlpo Järvinen WARN_ON(start > offset + len); 26471a028e50SDavid S. Miller 264851c56b00SEric Dumazet end = start + skb_frag_size(frag); 26491da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 2650c613c209SWillem de Bruijn u32 p_off, p_len, copied; 2651c613c209SWillem de Bruijn struct page *p; 265244bb9363SAl Viro __wsum csum2; 26531da177e4SLinus Torvalds u8 *vaddr; 26541da177e4SLinus Torvalds 26551da177e4SLinus Torvalds if (copy > len) 26561da177e4SLinus Torvalds copy = len; 2657c613c209SWillem de Bruijn 2658c613c209SWillem de Bruijn skb_frag_foreach_page(frag, 2659b54c9d5bSJonathan Lemon skb_frag_off(frag) + offset - start, 2660c613c209SWillem de Bruijn copy, p, p_off, p_len, copied) { 2661c613c209SWillem de Bruijn vaddr = kmap_atomic(p); 26622544af03SMatteo Croce csum2 = INDIRECT_CALL_1(ops->update, 26632544af03SMatteo Croce csum_partial_ext, 26642544af03SMatteo Croce vaddr + p_off, p_len, 0); 266551c56b00SEric Dumazet kunmap_atomic(vaddr); 26662544af03SMatteo Croce csum = INDIRECT_CALL_1(ops->combine, 26672544af03SMatteo Croce csum_block_add_ext, csum, 26682544af03SMatteo Croce csum2, pos, p_len); 2669c613c209SWillem de Bruijn pos += p_len; 2670c613c209SWillem de Bruijn } 2671c613c209SWillem de Bruijn 26721da177e4SLinus Torvalds if (!(len -= copy)) 26731da177e4SLinus Torvalds return csum; 26741da177e4SLinus Torvalds offset += copy; 26751da177e4SLinus Torvalds } 26761a028e50SDavid S. Miller start = end; 26771da177e4SLinus Torvalds } 26781da177e4SLinus Torvalds 2679fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 26801a028e50SDavid S. Miller int end; 26811da177e4SLinus Torvalds 2682547b792cSIlpo Järvinen WARN_ON(start > offset + len); 26831a028e50SDavid S. Miller 2684fbb398a8SDavid S. Miller end = start + frag_iter->len; 26851da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 26865f92a738SAl Viro __wsum csum2; 26871da177e4SLinus Torvalds if (copy > len) 26881da177e4SLinus Torvalds copy = len; 26892817a336SDaniel Borkmann csum2 = __skb_checksum(frag_iter, offset - start, 26902817a336SDaniel Borkmann copy, 0, ops); 26912544af03SMatteo Croce csum = INDIRECT_CALL_1(ops->combine, csum_block_add_ext, 26922544af03SMatteo Croce csum, csum2, pos, copy); 26931da177e4SLinus Torvalds if ((len -= copy) == 0) 26941da177e4SLinus Torvalds return csum; 26951da177e4SLinus Torvalds offset += copy; 26961da177e4SLinus Torvalds pos += copy; 26971da177e4SLinus Torvalds } 26981a028e50SDavid S. Miller start = end; 26991da177e4SLinus Torvalds } 270009a62660SKris Katterjohn BUG_ON(len); 27011da177e4SLinus Torvalds 27021da177e4SLinus Torvalds return csum; 27031da177e4SLinus Torvalds } 27042817a336SDaniel Borkmann EXPORT_SYMBOL(__skb_checksum); 27052817a336SDaniel Borkmann 27062817a336SDaniel Borkmann __wsum skb_checksum(const struct sk_buff *skb, int offset, 27072817a336SDaniel Borkmann int len, __wsum csum) 27082817a336SDaniel Borkmann { 27092817a336SDaniel Borkmann const struct skb_checksum_ops ops = { 2710cea80ea8SDaniel Borkmann .update = csum_partial_ext, 27112817a336SDaniel Borkmann .combine = csum_block_add_ext, 27122817a336SDaniel Borkmann }; 27132817a336SDaniel Borkmann 27142817a336SDaniel Borkmann return __skb_checksum(skb, offset, len, csum, &ops); 27152817a336SDaniel Borkmann } 2716b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_checksum); 27171da177e4SLinus Torvalds 27181da177e4SLinus Torvalds /* Both of above in one bottle. */ 27191da177e4SLinus Torvalds 272081d77662SAl Viro __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 27218d5930dfSAl Viro u8 *to, int len) 27221da177e4SLinus Torvalds { 27231a028e50SDavid S. Miller int start = skb_headlen(skb); 27241a028e50SDavid S. Miller int i, copy = start - offset; 2725fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 27261da177e4SLinus Torvalds int pos = 0; 27278d5930dfSAl Viro __wsum csum = 0; 27281da177e4SLinus Torvalds 27291da177e4SLinus Torvalds /* Copy header. */ 27301da177e4SLinus Torvalds if (copy > 0) { 27311da177e4SLinus Torvalds if (copy > len) 27321da177e4SLinus Torvalds copy = len; 27331da177e4SLinus Torvalds csum = csum_partial_copy_nocheck(skb->data + offset, to, 2734cc44c17bSAl Viro copy); 27351da177e4SLinus Torvalds if ((len -= copy) == 0) 27361da177e4SLinus Torvalds return csum; 27371da177e4SLinus Torvalds offset += copy; 27381da177e4SLinus Torvalds to += copy; 27391da177e4SLinus Torvalds pos = copy; 27401da177e4SLinus Torvalds } 27411da177e4SLinus Torvalds 27421da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 27431a028e50SDavid S. Miller int end; 27441da177e4SLinus Torvalds 2745547b792cSIlpo Järvinen WARN_ON(start > offset + len); 27461a028e50SDavid S. Miller 27479e903e08SEric Dumazet end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]); 27481da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 2749c613c209SWillem de Bruijn skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 2750c613c209SWillem de Bruijn u32 p_off, p_len, copied; 2751c613c209SWillem de Bruijn struct page *p; 27525084205fSAl Viro __wsum csum2; 27531da177e4SLinus Torvalds u8 *vaddr; 27541da177e4SLinus Torvalds 27551da177e4SLinus Torvalds if (copy > len) 27561da177e4SLinus Torvalds copy = len; 2757c613c209SWillem de Bruijn 2758c613c209SWillem de Bruijn skb_frag_foreach_page(frag, 2759b54c9d5bSJonathan Lemon skb_frag_off(frag) + offset - start, 2760c613c209SWillem de Bruijn copy, p, p_off, p_len, copied) { 2761c613c209SWillem de Bruijn vaddr = kmap_atomic(p); 2762c613c209SWillem de Bruijn csum2 = csum_partial_copy_nocheck(vaddr + p_off, 2763c613c209SWillem de Bruijn to + copied, 2764cc44c17bSAl Viro p_len); 276551c56b00SEric Dumazet kunmap_atomic(vaddr); 27661da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 2767c613c209SWillem de Bruijn pos += p_len; 2768c613c209SWillem de Bruijn } 2769c613c209SWillem de Bruijn 27701da177e4SLinus Torvalds if (!(len -= copy)) 27711da177e4SLinus Torvalds return csum; 27721da177e4SLinus Torvalds offset += copy; 27731da177e4SLinus Torvalds to += copy; 27741da177e4SLinus Torvalds } 27751a028e50SDavid S. Miller start = end; 27761da177e4SLinus Torvalds } 27771da177e4SLinus Torvalds 2778fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 277981d77662SAl Viro __wsum csum2; 27801a028e50SDavid S. Miller int end; 27811da177e4SLinus Torvalds 2782547b792cSIlpo Järvinen WARN_ON(start > offset + len); 27831a028e50SDavid S. Miller 2784fbb398a8SDavid S. Miller end = start + frag_iter->len; 27851da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 27861da177e4SLinus Torvalds if (copy > len) 27871da177e4SLinus Torvalds copy = len; 2788fbb398a8SDavid S. Miller csum2 = skb_copy_and_csum_bits(frag_iter, 27891a028e50SDavid S. Miller offset - start, 27908d5930dfSAl Viro to, copy); 27911da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 27921da177e4SLinus Torvalds if ((len -= copy) == 0) 27931da177e4SLinus Torvalds return csum; 27941da177e4SLinus Torvalds offset += copy; 27951da177e4SLinus Torvalds to += copy; 27961da177e4SLinus Torvalds pos += copy; 27971da177e4SLinus Torvalds } 27981a028e50SDavid S. Miller start = end; 27991da177e4SLinus Torvalds } 280009a62660SKris Katterjohn BUG_ON(len); 28011da177e4SLinus Torvalds return csum; 28021da177e4SLinus Torvalds } 2803b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_and_csum_bits); 28041da177e4SLinus Torvalds 280549f8e832SCong Wang __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len) 280649f8e832SCong Wang { 280749f8e832SCong Wang __sum16 sum; 280849f8e832SCong Wang 280949f8e832SCong Wang sum = csum_fold(skb_checksum(skb, 0, len, skb->csum)); 281014641931SCong Wang /* See comments in __skb_checksum_complete(). */ 281149f8e832SCong Wang if (likely(!sum)) { 281249f8e832SCong Wang if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 281349f8e832SCong Wang !skb->csum_complete_sw) 28147fe50ac8SCong Wang netdev_rx_csum_fault(skb->dev, skb); 281549f8e832SCong Wang } 281649f8e832SCong Wang if (!skb_shared(skb)) 281749f8e832SCong Wang skb->csum_valid = !sum; 281849f8e832SCong Wang return sum; 281949f8e832SCong Wang } 282049f8e832SCong Wang EXPORT_SYMBOL(__skb_checksum_complete_head); 282149f8e832SCong Wang 282214641931SCong Wang /* This function assumes skb->csum already holds pseudo header's checksum, 282314641931SCong Wang * which has been changed from the hardware checksum, for example, by 282414641931SCong Wang * __skb_checksum_validate_complete(). And, the original skb->csum must 282514641931SCong Wang * have been validated unsuccessfully for CHECKSUM_COMPLETE case. 282614641931SCong Wang * 282714641931SCong Wang * It returns non-zero if the recomputed checksum is still invalid, otherwise 282814641931SCong Wang * zero. The new checksum is stored back into skb->csum unless the skb is 282914641931SCong Wang * shared. 283014641931SCong Wang */ 283149f8e832SCong Wang __sum16 __skb_checksum_complete(struct sk_buff *skb) 283249f8e832SCong Wang { 283349f8e832SCong Wang __wsum csum; 283449f8e832SCong Wang __sum16 sum; 283549f8e832SCong Wang 283649f8e832SCong Wang csum = skb_checksum(skb, 0, skb->len, 0); 283749f8e832SCong Wang 283849f8e832SCong Wang sum = csum_fold(csum_add(skb->csum, csum)); 283914641931SCong Wang /* This check is inverted, because we already knew the hardware 284014641931SCong Wang * checksum is invalid before calling this function. So, if the 284114641931SCong Wang * re-computed checksum is valid instead, then we have a mismatch 284214641931SCong Wang * between the original skb->csum and skb_checksum(). This means either 284314641931SCong Wang * the original hardware checksum is incorrect or we screw up skb->csum 284414641931SCong Wang * when moving skb->data around. 284514641931SCong Wang */ 284649f8e832SCong Wang if (likely(!sum)) { 284749f8e832SCong Wang if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && 284849f8e832SCong Wang !skb->csum_complete_sw) 28497fe50ac8SCong Wang netdev_rx_csum_fault(skb->dev, skb); 285049f8e832SCong Wang } 285149f8e832SCong Wang 285249f8e832SCong Wang if (!skb_shared(skb)) { 285349f8e832SCong Wang /* Save full packet checksum */ 285449f8e832SCong Wang skb->csum = csum; 285549f8e832SCong Wang skb->ip_summed = CHECKSUM_COMPLETE; 285649f8e832SCong Wang skb->csum_complete_sw = 1; 285749f8e832SCong Wang skb->csum_valid = !sum; 285849f8e832SCong Wang } 285949f8e832SCong Wang 286049f8e832SCong Wang return sum; 286149f8e832SCong Wang } 286249f8e832SCong Wang EXPORT_SYMBOL(__skb_checksum_complete); 286349f8e832SCong Wang 28649617813dSDavide Caratti static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum) 28659617813dSDavide Caratti { 28669617813dSDavide Caratti net_warn_ratelimited( 28679617813dSDavide Caratti "%s: attempt to compute crc32c without libcrc32c.ko\n", 28689617813dSDavide Caratti __func__); 28699617813dSDavide Caratti return 0; 28709617813dSDavide Caratti } 28719617813dSDavide Caratti 28729617813dSDavide Caratti static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2, 28739617813dSDavide Caratti int offset, int len) 28749617813dSDavide Caratti { 28759617813dSDavide Caratti net_warn_ratelimited( 28769617813dSDavide Caratti "%s: attempt to compute crc32c without libcrc32c.ko\n", 28779617813dSDavide Caratti __func__); 28789617813dSDavide Caratti return 0; 28799617813dSDavide Caratti } 28809617813dSDavide Caratti 28819617813dSDavide Caratti static const struct skb_checksum_ops default_crc32c_ops = { 28829617813dSDavide Caratti .update = warn_crc32c_csum_update, 28839617813dSDavide Caratti .combine = warn_crc32c_csum_combine, 28849617813dSDavide Caratti }; 28859617813dSDavide Caratti 28869617813dSDavide Caratti const struct skb_checksum_ops *crc32c_csum_stub __read_mostly = 28879617813dSDavide Caratti &default_crc32c_ops; 28889617813dSDavide Caratti EXPORT_SYMBOL(crc32c_csum_stub); 28899617813dSDavide Caratti 2890af2806f8SThomas Graf /** 2891af2806f8SThomas Graf * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy() 2892af2806f8SThomas Graf * @from: source buffer 2893af2806f8SThomas Graf * 2894af2806f8SThomas Graf * Calculates the amount of linear headroom needed in the 'to' skb passed 2895af2806f8SThomas Graf * into skb_zerocopy(). 2896af2806f8SThomas Graf */ 2897af2806f8SThomas Graf unsigned int 2898af2806f8SThomas Graf skb_zerocopy_headlen(const struct sk_buff *from) 2899af2806f8SThomas Graf { 2900af2806f8SThomas Graf unsigned int hlen = 0; 2901af2806f8SThomas Graf 2902af2806f8SThomas Graf if (!from->head_frag || 2903af2806f8SThomas Graf skb_headlen(from) < L1_CACHE_BYTES || 2904af2806f8SThomas Graf skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) 2905af2806f8SThomas Graf hlen = skb_headlen(from); 2906af2806f8SThomas Graf 2907af2806f8SThomas Graf if (skb_has_frag_list(from)) 2908af2806f8SThomas Graf hlen = from->len; 2909af2806f8SThomas Graf 2910af2806f8SThomas Graf return hlen; 2911af2806f8SThomas Graf } 2912af2806f8SThomas Graf EXPORT_SYMBOL_GPL(skb_zerocopy_headlen); 2913af2806f8SThomas Graf 2914af2806f8SThomas Graf /** 2915af2806f8SThomas Graf * skb_zerocopy - Zero copy skb to skb 2916af2806f8SThomas Graf * @to: destination buffer 29177fceb4deSMasanari Iida * @from: source buffer 2918af2806f8SThomas Graf * @len: number of bytes to copy from source buffer 2919af2806f8SThomas Graf * @hlen: size of linear headroom in destination buffer 2920af2806f8SThomas Graf * 2921af2806f8SThomas Graf * Copies up to `len` bytes from `from` to `to` by creating references 2922af2806f8SThomas Graf * to the frags in the source buffer. 2923af2806f8SThomas Graf * 2924af2806f8SThomas Graf * The `hlen` as calculated by skb_zerocopy_headlen() specifies the 2925af2806f8SThomas Graf * headroom in the `to` buffer. 292636d5fe6aSZoltan Kiss * 292736d5fe6aSZoltan Kiss * Return value: 292836d5fe6aSZoltan Kiss * 0: everything is OK 292936d5fe6aSZoltan Kiss * -ENOMEM: couldn't orphan frags of @from due to lack of memory 293036d5fe6aSZoltan Kiss * -EFAULT: skb_copy_bits() found some problem with skb geometry 2931af2806f8SThomas Graf */ 293236d5fe6aSZoltan Kiss int 293336d5fe6aSZoltan Kiss skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) 2934af2806f8SThomas Graf { 2935af2806f8SThomas Graf int i, j = 0; 2936af2806f8SThomas Graf int plen = 0; /* length of skb->head fragment */ 293736d5fe6aSZoltan Kiss int ret; 2938af2806f8SThomas Graf struct page *page; 2939af2806f8SThomas Graf unsigned int offset; 2940af2806f8SThomas Graf 2941af2806f8SThomas Graf BUG_ON(!from->head_frag && !hlen); 2942af2806f8SThomas Graf 2943af2806f8SThomas Graf /* dont bother with small payloads */ 294436d5fe6aSZoltan Kiss if (len <= skb_tailroom(to)) 294536d5fe6aSZoltan Kiss return skb_copy_bits(from, 0, skb_put(to, len), len); 2946af2806f8SThomas Graf 2947af2806f8SThomas Graf if (hlen) { 294836d5fe6aSZoltan Kiss ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen); 294936d5fe6aSZoltan Kiss if (unlikely(ret)) 295036d5fe6aSZoltan Kiss return ret; 2951af2806f8SThomas Graf len -= hlen; 2952af2806f8SThomas Graf } else { 2953af2806f8SThomas Graf plen = min_t(int, skb_headlen(from), len); 2954af2806f8SThomas Graf if (plen) { 2955af2806f8SThomas Graf page = virt_to_head_page(from->head); 2956af2806f8SThomas Graf offset = from->data - (unsigned char *)page_address(page); 2957af2806f8SThomas Graf __skb_fill_page_desc(to, 0, page, offset, plen); 2958af2806f8SThomas Graf get_page(page); 2959af2806f8SThomas Graf j = 1; 2960af2806f8SThomas Graf len -= plen; 2961af2806f8SThomas Graf } 2962af2806f8SThomas Graf } 2963af2806f8SThomas Graf 2964af2806f8SThomas Graf to->truesize += len + plen; 2965af2806f8SThomas Graf to->len += len + plen; 2966af2806f8SThomas Graf to->data_len += len + plen; 2967af2806f8SThomas Graf 296836d5fe6aSZoltan Kiss if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) { 296936d5fe6aSZoltan Kiss skb_tx_error(from); 297036d5fe6aSZoltan Kiss return -ENOMEM; 297136d5fe6aSZoltan Kiss } 29721f8b977aSWillem de Bruijn skb_zerocopy_clone(to, from, GFP_ATOMIC); 297336d5fe6aSZoltan Kiss 2974af2806f8SThomas Graf for (i = 0; i < skb_shinfo(from)->nr_frags; i++) { 2975d8e18a51SMatthew Wilcox (Oracle) int size; 2976d8e18a51SMatthew Wilcox (Oracle) 2977af2806f8SThomas Graf if (!len) 2978af2806f8SThomas Graf break; 2979af2806f8SThomas Graf skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i]; 2980d8e18a51SMatthew Wilcox (Oracle) size = min_t(int, skb_frag_size(&skb_shinfo(to)->frags[j]), 2981d8e18a51SMatthew Wilcox (Oracle) len); 2982d8e18a51SMatthew Wilcox (Oracle) skb_frag_size_set(&skb_shinfo(to)->frags[j], size); 2983d8e18a51SMatthew Wilcox (Oracle) len -= size; 2984af2806f8SThomas Graf skb_frag_ref(to, j); 2985af2806f8SThomas Graf j++; 2986af2806f8SThomas Graf } 2987af2806f8SThomas Graf skb_shinfo(to)->nr_frags = j; 298836d5fe6aSZoltan Kiss 298936d5fe6aSZoltan Kiss return 0; 2990af2806f8SThomas Graf } 2991af2806f8SThomas Graf EXPORT_SYMBOL_GPL(skb_zerocopy); 2992af2806f8SThomas Graf 29931da177e4SLinus Torvalds void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) 29941da177e4SLinus Torvalds { 2995d3bc23e7SAl Viro __wsum csum; 29961da177e4SLinus Torvalds long csstart; 29971da177e4SLinus Torvalds 299884fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) 299955508d60SMichał Mirosław csstart = skb_checksum_start_offset(skb); 30001da177e4SLinus Torvalds else 30011da177e4SLinus Torvalds csstart = skb_headlen(skb); 30021da177e4SLinus Torvalds 300309a62660SKris Katterjohn BUG_ON(csstart > skb_headlen(skb)); 30041da177e4SLinus Torvalds 3005d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data(skb, to, csstart); 30061da177e4SLinus Torvalds 30071da177e4SLinus Torvalds csum = 0; 30081da177e4SLinus Torvalds if (csstart != skb->len) 30091da177e4SLinus Torvalds csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, 30108d5930dfSAl Viro skb->len - csstart); 30111da177e4SLinus Torvalds 301284fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) { 3013ff1dcadbSAl Viro long csstuff = csstart + skb->csum_offset; 30141da177e4SLinus Torvalds 3015d3bc23e7SAl Viro *((__sum16 *)(to + csstuff)) = csum_fold(csum); 30161da177e4SLinus Torvalds } 30171da177e4SLinus Torvalds } 3018b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_and_csum_dev); 30191da177e4SLinus Torvalds 30201da177e4SLinus Torvalds /** 30211da177e4SLinus Torvalds * skb_dequeue - remove from the head of the queue 30221da177e4SLinus Torvalds * @list: list to dequeue from 30231da177e4SLinus Torvalds * 30241da177e4SLinus Torvalds * Remove the head of the list. The list lock is taken so the function 30251da177e4SLinus Torvalds * may be used safely with other locking list functions. The head item is 30261da177e4SLinus Torvalds * returned or %NULL if the list is empty. 30271da177e4SLinus Torvalds */ 30281da177e4SLinus Torvalds 30291da177e4SLinus Torvalds struct sk_buff *skb_dequeue(struct sk_buff_head *list) 30301da177e4SLinus Torvalds { 30311da177e4SLinus Torvalds unsigned long flags; 30321da177e4SLinus Torvalds struct sk_buff *result; 30331da177e4SLinus Torvalds 30341da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 30351da177e4SLinus Torvalds result = __skb_dequeue(list); 30361da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 30371da177e4SLinus Torvalds return result; 30381da177e4SLinus Torvalds } 3039b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_dequeue); 30401da177e4SLinus Torvalds 30411da177e4SLinus Torvalds /** 30421da177e4SLinus Torvalds * skb_dequeue_tail - remove from the tail of the queue 30431da177e4SLinus Torvalds * @list: list to dequeue from 30441da177e4SLinus Torvalds * 30451da177e4SLinus Torvalds * Remove the tail of the list. The list lock is taken so the function 30461da177e4SLinus Torvalds * may be used safely with other locking list functions. The tail item is 30471da177e4SLinus Torvalds * returned or %NULL if the list is empty. 30481da177e4SLinus Torvalds */ 30491da177e4SLinus Torvalds struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) 30501da177e4SLinus Torvalds { 30511da177e4SLinus Torvalds unsigned long flags; 30521da177e4SLinus Torvalds struct sk_buff *result; 30531da177e4SLinus Torvalds 30541da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 30551da177e4SLinus Torvalds result = __skb_dequeue_tail(list); 30561da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 30571da177e4SLinus Torvalds return result; 30581da177e4SLinus Torvalds } 3059b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_dequeue_tail); 30601da177e4SLinus Torvalds 30611da177e4SLinus Torvalds /** 30621da177e4SLinus Torvalds * skb_queue_purge - empty a list 30631da177e4SLinus Torvalds * @list: list to empty 30641da177e4SLinus Torvalds * 30651da177e4SLinus Torvalds * Delete all buffers on an &sk_buff list. Each buffer is removed from 30661da177e4SLinus Torvalds * the list and one reference dropped. This function takes the list 30671da177e4SLinus Torvalds * lock and is atomic with respect to other list locking functions. 30681da177e4SLinus Torvalds */ 30691da177e4SLinus Torvalds void skb_queue_purge(struct sk_buff_head *list) 30701da177e4SLinus Torvalds { 30711da177e4SLinus Torvalds struct sk_buff *skb; 30721da177e4SLinus Torvalds while ((skb = skb_dequeue(list)) != NULL) 30731da177e4SLinus Torvalds kfree_skb(skb); 30741da177e4SLinus Torvalds } 3075b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_purge); 30761da177e4SLinus Torvalds 30771da177e4SLinus Torvalds /** 30789f5afeaeSYaogong Wang * skb_rbtree_purge - empty a skb rbtree 30799f5afeaeSYaogong Wang * @root: root of the rbtree to empty 3080385114deSPeter Oskolkov * Return value: the sum of truesizes of all purged skbs. 30819f5afeaeSYaogong Wang * 30829f5afeaeSYaogong Wang * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from 30839f5afeaeSYaogong Wang * the list and one reference dropped. This function does not take 30849f5afeaeSYaogong Wang * any lock. Synchronization should be handled by the caller (e.g., TCP 30859f5afeaeSYaogong Wang * out-of-order queue is protected by the socket lock). 30869f5afeaeSYaogong Wang */ 3087385114deSPeter Oskolkov unsigned int skb_rbtree_purge(struct rb_root *root) 30889f5afeaeSYaogong Wang { 30897c90584cSEric Dumazet struct rb_node *p = rb_first(root); 3090385114deSPeter Oskolkov unsigned int sum = 0; 30919f5afeaeSYaogong Wang 30927c90584cSEric Dumazet while (p) { 30937c90584cSEric Dumazet struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode); 30947c90584cSEric Dumazet 30957c90584cSEric Dumazet p = rb_next(p); 30967c90584cSEric Dumazet rb_erase(&skb->rbnode, root); 3097385114deSPeter Oskolkov sum += skb->truesize; 30989f5afeaeSYaogong Wang kfree_skb(skb); 30997c90584cSEric Dumazet } 3100385114deSPeter Oskolkov return sum; 31019f5afeaeSYaogong Wang } 31029f5afeaeSYaogong Wang 31039f5afeaeSYaogong Wang /** 31041da177e4SLinus Torvalds * skb_queue_head - queue a buffer at the list head 31051da177e4SLinus Torvalds * @list: list to use 31061da177e4SLinus Torvalds * @newsk: buffer to queue 31071da177e4SLinus Torvalds * 31081da177e4SLinus Torvalds * Queue a buffer at the start of the list. This function takes the 31091da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 31101da177e4SLinus Torvalds * safely. 31111da177e4SLinus Torvalds * 31121da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 31131da177e4SLinus Torvalds */ 31141da177e4SLinus Torvalds void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) 31151da177e4SLinus Torvalds { 31161da177e4SLinus Torvalds unsigned long flags; 31171da177e4SLinus Torvalds 31181da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 31191da177e4SLinus Torvalds __skb_queue_head(list, newsk); 31201da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 31211da177e4SLinus Torvalds } 3122b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_head); 31231da177e4SLinus Torvalds 31241da177e4SLinus Torvalds /** 31251da177e4SLinus Torvalds * skb_queue_tail - queue a buffer at the list tail 31261da177e4SLinus Torvalds * @list: list to use 31271da177e4SLinus Torvalds * @newsk: buffer to queue 31281da177e4SLinus Torvalds * 31291da177e4SLinus Torvalds * Queue a buffer at the tail of the list. This function takes the 31301da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 31311da177e4SLinus Torvalds * safely. 31321da177e4SLinus Torvalds * 31331da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 31341da177e4SLinus Torvalds */ 31351da177e4SLinus Torvalds void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) 31361da177e4SLinus Torvalds { 31371da177e4SLinus Torvalds unsigned long flags; 31381da177e4SLinus Torvalds 31391da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 31401da177e4SLinus Torvalds __skb_queue_tail(list, newsk); 31411da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 31421da177e4SLinus Torvalds } 3143b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_tail); 31448728b834SDavid S. Miller 31451da177e4SLinus Torvalds /** 31461da177e4SLinus Torvalds * skb_unlink - remove a buffer from a list 31471da177e4SLinus Torvalds * @skb: buffer to remove 31488728b834SDavid S. Miller * @list: list to use 31491da177e4SLinus Torvalds * 31508728b834SDavid S. Miller * Remove a packet from a list. The list locks are taken and this 31518728b834SDavid S. Miller * function is atomic with respect to other list locked calls 31521da177e4SLinus Torvalds * 31538728b834SDavid S. Miller * You must know what list the SKB is on. 31541da177e4SLinus Torvalds */ 31558728b834SDavid S. Miller void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 31561da177e4SLinus Torvalds { 31571da177e4SLinus Torvalds unsigned long flags; 31581da177e4SLinus Torvalds 31591da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 31608728b834SDavid S. Miller __skb_unlink(skb, list); 31611da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 31621da177e4SLinus Torvalds } 3163b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_unlink); 31641da177e4SLinus Torvalds 31651da177e4SLinus Torvalds /** 31661da177e4SLinus Torvalds * skb_append - append a buffer 31671da177e4SLinus Torvalds * @old: buffer to insert after 31681da177e4SLinus Torvalds * @newsk: buffer to insert 31698728b834SDavid S. Miller * @list: list to use 31701da177e4SLinus Torvalds * 31711da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 31721da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls. 31731da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 31741da177e4SLinus Torvalds */ 31758728b834SDavid S. Miller void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 31761da177e4SLinus Torvalds { 31771da177e4SLinus Torvalds unsigned long flags; 31781da177e4SLinus Torvalds 31798728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 31807de6c033SGerrit Renker __skb_queue_after(list, old, newsk); 31818728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 31821da177e4SLinus Torvalds } 3183b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_append); 31841da177e4SLinus Torvalds 31851da177e4SLinus Torvalds static inline void skb_split_inside_header(struct sk_buff *skb, 31861da177e4SLinus Torvalds struct sk_buff* skb1, 31871da177e4SLinus Torvalds const u32 len, const int pos) 31881da177e4SLinus Torvalds { 31891da177e4SLinus Torvalds int i; 31901da177e4SLinus Torvalds 3191d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len), 3192d626f62bSArnaldo Carvalho de Melo pos - len); 31931da177e4SLinus Torvalds /* And move data appendix as is. */ 31941da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 31951da177e4SLinus Torvalds skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; 31961da177e4SLinus Torvalds 31971da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; 31981da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 31991da177e4SLinus Torvalds skb1->data_len = skb->data_len; 32001da177e4SLinus Torvalds skb1->len += skb1->data_len; 32011da177e4SLinus Torvalds skb->data_len = 0; 32021da177e4SLinus Torvalds skb->len = len; 320327a884dcSArnaldo Carvalho de Melo skb_set_tail_pointer(skb, len); 32041da177e4SLinus Torvalds } 32051da177e4SLinus Torvalds 32061da177e4SLinus Torvalds static inline void skb_split_no_header(struct sk_buff *skb, 32071da177e4SLinus Torvalds struct sk_buff* skb1, 32081da177e4SLinus Torvalds const u32 len, int pos) 32091da177e4SLinus Torvalds { 32101da177e4SLinus Torvalds int i, k = 0; 32111da177e4SLinus Torvalds const int nfrags = skb_shinfo(skb)->nr_frags; 32121da177e4SLinus Torvalds 32131da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 32141da177e4SLinus Torvalds skb1->len = skb1->data_len = skb->len - len; 32151da177e4SLinus Torvalds skb->len = len; 32161da177e4SLinus Torvalds skb->data_len = len - pos; 32171da177e4SLinus Torvalds 32181da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 32199e903e08SEric Dumazet int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); 32201da177e4SLinus Torvalds 32211da177e4SLinus Torvalds if (pos + size > len) { 32221da177e4SLinus Torvalds skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; 32231da177e4SLinus Torvalds 32241da177e4SLinus Torvalds if (pos < len) { 32251da177e4SLinus Torvalds /* Split frag. 32261da177e4SLinus Torvalds * We have two variants in this case: 32271da177e4SLinus Torvalds * 1. Move all the frag to the second 32281da177e4SLinus Torvalds * part, if it is possible. F.e. 32291da177e4SLinus Torvalds * this approach is mandatory for TUX, 32301da177e4SLinus Torvalds * where splitting is expensive. 32311da177e4SLinus Torvalds * 2. Split is accurately. We make this. 32321da177e4SLinus Torvalds */ 3233ea2ab693SIan Campbell skb_frag_ref(skb, i); 3234b54c9d5bSJonathan Lemon skb_frag_off_add(&skb_shinfo(skb1)->frags[0], len - pos); 32359e903e08SEric Dumazet skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos); 32369e903e08SEric Dumazet skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos); 32371da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 32381da177e4SLinus Torvalds } 32391da177e4SLinus Torvalds k++; 32401da177e4SLinus Torvalds } else 32411da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 32421da177e4SLinus Torvalds pos += size; 32431da177e4SLinus Torvalds } 32441da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = k; 32451da177e4SLinus Torvalds } 32461da177e4SLinus Torvalds 32471da177e4SLinus Torvalds /** 32481da177e4SLinus Torvalds * skb_split - Split fragmented skb to two parts at length len. 32491da177e4SLinus Torvalds * @skb: the buffer to split 32501da177e4SLinus Torvalds * @skb1: the buffer to receive the second part 32511da177e4SLinus Torvalds * @len: new length for skb 32521da177e4SLinus Torvalds */ 32531da177e4SLinus Torvalds void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) 32541da177e4SLinus Torvalds { 32551da177e4SLinus Torvalds int pos = skb_headlen(skb); 32561da177e4SLinus Torvalds 3257fff88030SWillem de Bruijn skb_shinfo(skb1)->tx_flags |= skb_shinfo(skb)->tx_flags & 3258fff88030SWillem de Bruijn SKBTX_SHARED_FRAG; 32591f8b977aSWillem de Bruijn skb_zerocopy_clone(skb1, skb, 0); 32601da177e4SLinus Torvalds if (len < pos) /* Split line is inside header. */ 32611da177e4SLinus Torvalds skb_split_inside_header(skb, skb1, len, pos); 32621da177e4SLinus Torvalds else /* Second chunk has no header, nothing to copy. */ 32631da177e4SLinus Torvalds skb_split_no_header(skb, skb1, len, pos); 32641da177e4SLinus Torvalds } 3265b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_split); 32661da177e4SLinus Torvalds 32679f782db3SIlpo Järvinen /* Shifting from/to a cloned skb is a no-go. 32689f782db3SIlpo Järvinen * 32699f782db3SIlpo Järvinen * Caller cannot keep skb_shinfo related pointers past calling here! 32709f782db3SIlpo Järvinen */ 3271832d11c5SIlpo Järvinen static int skb_prepare_for_shift(struct sk_buff *skb) 3272832d11c5SIlpo Järvinen { 32730ace2856SIlpo Järvinen return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC); 3274832d11c5SIlpo Järvinen } 3275832d11c5SIlpo Järvinen 3276832d11c5SIlpo Järvinen /** 3277832d11c5SIlpo Järvinen * skb_shift - Shifts paged data partially from skb to another 3278832d11c5SIlpo Järvinen * @tgt: buffer into which tail data gets added 3279832d11c5SIlpo Järvinen * @skb: buffer from which the paged data comes from 3280832d11c5SIlpo Järvinen * @shiftlen: shift up to this many bytes 3281832d11c5SIlpo Järvinen * 3282832d11c5SIlpo Järvinen * Attempts to shift up to shiftlen worth of bytes, which may be less than 328320e994a0SFeng King * the length of the skb, from skb to tgt. Returns number bytes shifted. 3284832d11c5SIlpo Järvinen * It's up to caller to free skb if everything was shifted. 3285832d11c5SIlpo Järvinen * 3286832d11c5SIlpo Järvinen * If @tgt runs out of frags, the whole operation is aborted. 3287832d11c5SIlpo Järvinen * 3288832d11c5SIlpo Järvinen * Skb cannot include anything else but paged data while tgt is allowed 3289832d11c5SIlpo Järvinen * to have non-paged data as well. 3290832d11c5SIlpo Järvinen * 3291832d11c5SIlpo Järvinen * TODO: full sized shift could be optimized but that would need 3292832d11c5SIlpo Järvinen * specialized skb free'er to handle frags without up-to-date nr_frags. 3293832d11c5SIlpo Järvinen */ 3294832d11c5SIlpo Järvinen int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) 3295832d11c5SIlpo Järvinen { 3296832d11c5SIlpo Järvinen int from, to, merge, todo; 3297d8e18a51SMatthew Wilcox (Oracle) skb_frag_t *fragfrom, *fragto; 3298832d11c5SIlpo Järvinen 3299832d11c5SIlpo Järvinen BUG_ON(shiftlen > skb->len); 3300f8071cdeSEric Dumazet 3301f8071cdeSEric Dumazet if (skb_headlen(skb)) 3302f8071cdeSEric Dumazet return 0; 33031f8b977aSWillem de Bruijn if (skb_zcopy(tgt) || skb_zcopy(skb)) 33041f8b977aSWillem de Bruijn return 0; 3305832d11c5SIlpo Järvinen 3306832d11c5SIlpo Järvinen todo = shiftlen; 3307832d11c5SIlpo Järvinen from = 0; 3308832d11c5SIlpo Järvinen to = skb_shinfo(tgt)->nr_frags; 3309832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 3310832d11c5SIlpo Järvinen 3311832d11c5SIlpo Järvinen /* Actual merge is delayed until the point when we know we can 3312832d11c5SIlpo Järvinen * commit all, so that we don't have to undo partial changes 3313832d11c5SIlpo Järvinen */ 3314832d11c5SIlpo Järvinen if (!to || 3315ea2ab693SIan Campbell !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom), 3316b54c9d5bSJonathan Lemon skb_frag_off(fragfrom))) { 3317832d11c5SIlpo Järvinen merge = -1; 3318832d11c5SIlpo Järvinen } else { 3319832d11c5SIlpo Järvinen merge = to - 1; 3320832d11c5SIlpo Järvinen 33219e903e08SEric Dumazet todo -= skb_frag_size(fragfrom); 3322832d11c5SIlpo Järvinen if (todo < 0) { 3323832d11c5SIlpo Järvinen if (skb_prepare_for_shift(skb) || 3324832d11c5SIlpo Järvinen skb_prepare_for_shift(tgt)) 3325832d11c5SIlpo Järvinen return 0; 3326832d11c5SIlpo Järvinen 33279f782db3SIlpo Järvinen /* All previous frag pointers might be stale! */ 33289f782db3SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 3329832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[merge]; 3330832d11c5SIlpo Järvinen 33319e903e08SEric Dumazet skb_frag_size_add(fragto, shiftlen); 33329e903e08SEric Dumazet skb_frag_size_sub(fragfrom, shiftlen); 3333b54c9d5bSJonathan Lemon skb_frag_off_add(fragfrom, shiftlen); 3334832d11c5SIlpo Järvinen 3335832d11c5SIlpo Järvinen goto onlymerged; 3336832d11c5SIlpo Järvinen } 3337832d11c5SIlpo Järvinen 3338832d11c5SIlpo Järvinen from++; 3339832d11c5SIlpo Järvinen } 3340832d11c5SIlpo Järvinen 3341832d11c5SIlpo Järvinen /* Skip full, not-fitting skb to avoid expensive operations */ 3342832d11c5SIlpo Järvinen if ((shiftlen == skb->len) && 3343832d11c5SIlpo Järvinen (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to)) 3344832d11c5SIlpo Järvinen return 0; 3345832d11c5SIlpo Järvinen 3346832d11c5SIlpo Järvinen if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt)) 3347832d11c5SIlpo Järvinen return 0; 3348832d11c5SIlpo Järvinen 3349832d11c5SIlpo Järvinen while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) { 3350832d11c5SIlpo Järvinen if (to == MAX_SKB_FRAGS) 3351832d11c5SIlpo Järvinen return 0; 3352832d11c5SIlpo Järvinen 3353832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 3354832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[to]; 3355832d11c5SIlpo Järvinen 33569e903e08SEric Dumazet if (todo >= skb_frag_size(fragfrom)) { 3357832d11c5SIlpo Järvinen *fragto = *fragfrom; 33589e903e08SEric Dumazet todo -= skb_frag_size(fragfrom); 3359832d11c5SIlpo Järvinen from++; 3360832d11c5SIlpo Järvinen to++; 3361832d11c5SIlpo Järvinen 3362832d11c5SIlpo Järvinen } else { 3363ea2ab693SIan Campbell __skb_frag_ref(fragfrom); 3364b54c9d5bSJonathan Lemon skb_frag_page_copy(fragto, fragfrom); 3365b54c9d5bSJonathan Lemon skb_frag_off_copy(fragto, fragfrom); 33669e903e08SEric Dumazet skb_frag_size_set(fragto, todo); 3367832d11c5SIlpo Järvinen 3368b54c9d5bSJonathan Lemon skb_frag_off_add(fragfrom, todo); 33699e903e08SEric Dumazet skb_frag_size_sub(fragfrom, todo); 3370832d11c5SIlpo Järvinen todo = 0; 3371832d11c5SIlpo Järvinen 3372832d11c5SIlpo Järvinen to++; 3373832d11c5SIlpo Järvinen break; 3374832d11c5SIlpo Järvinen } 3375832d11c5SIlpo Järvinen } 3376832d11c5SIlpo Järvinen 3377832d11c5SIlpo Järvinen /* Ready to "commit" this state change to tgt */ 3378832d11c5SIlpo Järvinen skb_shinfo(tgt)->nr_frags = to; 3379832d11c5SIlpo Järvinen 3380832d11c5SIlpo Järvinen if (merge >= 0) { 3381832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[0]; 3382832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[merge]; 3383832d11c5SIlpo Järvinen 33849e903e08SEric Dumazet skb_frag_size_add(fragto, skb_frag_size(fragfrom)); 3385ea2ab693SIan Campbell __skb_frag_unref(fragfrom); 3386832d11c5SIlpo Järvinen } 3387832d11c5SIlpo Järvinen 3388832d11c5SIlpo Järvinen /* Reposition in the original skb */ 3389832d11c5SIlpo Järvinen to = 0; 3390832d11c5SIlpo Järvinen while (from < skb_shinfo(skb)->nr_frags) 3391832d11c5SIlpo Järvinen skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++]; 3392832d11c5SIlpo Järvinen skb_shinfo(skb)->nr_frags = to; 3393832d11c5SIlpo Järvinen 3394832d11c5SIlpo Järvinen BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags); 3395832d11c5SIlpo Järvinen 3396832d11c5SIlpo Järvinen onlymerged: 3397832d11c5SIlpo Järvinen /* Most likely the tgt won't ever need its checksum anymore, skb on 3398832d11c5SIlpo Järvinen * the other hand might need it if it needs to be resent 3399832d11c5SIlpo Järvinen */ 3400832d11c5SIlpo Järvinen tgt->ip_summed = CHECKSUM_PARTIAL; 3401832d11c5SIlpo Järvinen skb->ip_summed = CHECKSUM_PARTIAL; 3402832d11c5SIlpo Järvinen 3403832d11c5SIlpo Järvinen /* Yak, is it really working this way? Some helper please? */ 3404832d11c5SIlpo Järvinen skb->len -= shiftlen; 3405832d11c5SIlpo Järvinen skb->data_len -= shiftlen; 3406832d11c5SIlpo Järvinen skb->truesize -= shiftlen; 3407832d11c5SIlpo Järvinen tgt->len += shiftlen; 3408832d11c5SIlpo Järvinen tgt->data_len += shiftlen; 3409832d11c5SIlpo Järvinen tgt->truesize += shiftlen; 3410832d11c5SIlpo Järvinen 3411832d11c5SIlpo Järvinen return shiftlen; 3412832d11c5SIlpo Järvinen } 3413832d11c5SIlpo Järvinen 3414677e90edSThomas Graf /** 3415677e90edSThomas Graf * skb_prepare_seq_read - Prepare a sequential read of skb data 3416677e90edSThomas Graf * @skb: the buffer to read 3417677e90edSThomas Graf * @from: lower offset of data to be read 3418677e90edSThomas Graf * @to: upper offset of data to be read 3419677e90edSThomas Graf * @st: state variable 3420677e90edSThomas Graf * 3421677e90edSThomas Graf * Initializes the specified state variable. Must be called before 3422677e90edSThomas Graf * invoking skb_seq_read() for the first time. 3423677e90edSThomas Graf */ 3424677e90edSThomas Graf void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 3425677e90edSThomas Graf unsigned int to, struct skb_seq_state *st) 3426677e90edSThomas Graf { 3427677e90edSThomas Graf st->lower_offset = from; 3428677e90edSThomas Graf st->upper_offset = to; 3429677e90edSThomas Graf st->root_skb = st->cur_skb = skb; 3430677e90edSThomas Graf st->frag_idx = st->stepped_offset = 0; 3431677e90edSThomas Graf st->frag_data = NULL; 3432677e90edSThomas Graf } 3433b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_prepare_seq_read); 3434677e90edSThomas Graf 3435677e90edSThomas Graf /** 3436677e90edSThomas Graf * skb_seq_read - Sequentially read skb data 3437677e90edSThomas Graf * @consumed: number of bytes consumed by the caller so far 3438677e90edSThomas Graf * @data: destination pointer for data to be returned 3439677e90edSThomas Graf * @st: state variable 3440677e90edSThomas Graf * 3441bc32383cSMathias Krause * Reads a block of skb data at @consumed relative to the 3442677e90edSThomas Graf * lower offset specified to skb_prepare_seq_read(). Assigns 3443bc32383cSMathias Krause * the head of the data block to @data and returns the length 3444677e90edSThomas Graf * of the block or 0 if the end of the skb data or the upper 3445677e90edSThomas Graf * offset has been reached. 3446677e90edSThomas Graf * 3447677e90edSThomas Graf * The caller is not required to consume all of the data 3448bc32383cSMathias Krause * returned, i.e. @consumed is typically set to the number 3449677e90edSThomas Graf * of bytes already consumed and the next call to 3450677e90edSThomas Graf * skb_seq_read() will return the remaining part of the block. 3451677e90edSThomas Graf * 345225985edcSLucas De Marchi * Note 1: The size of each block of data returned can be arbitrary, 3453e793c0f7SMasanari Iida * this limitation is the cost for zerocopy sequential 3454677e90edSThomas Graf * reads of potentially non linear data. 3455677e90edSThomas Graf * 3456bc2cda1eSRandy Dunlap * Note 2: Fragment lists within fragments are not implemented 3457677e90edSThomas Graf * at the moment, state->root_skb could be replaced with 3458677e90edSThomas Graf * a stack for this purpose. 3459677e90edSThomas Graf */ 3460677e90edSThomas Graf unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 3461677e90edSThomas Graf struct skb_seq_state *st) 3462677e90edSThomas Graf { 3463677e90edSThomas Graf unsigned int block_limit, abs_offset = consumed + st->lower_offset; 3464677e90edSThomas Graf skb_frag_t *frag; 3465677e90edSThomas Graf 3466aeb193eaSWedson Almeida Filho if (unlikely(abs_offset >= st->upper_offset)) { 3467aeb193eaSWedson Almeida Filho if (st->frag_data) { 3468aeb193eaSWedson Almeida Filho kunmap_atomic(st->frag_data); 3469aeb193eaSWedson Almeida Filho st->frag_data = NULL; 3470aeb193eaSWedson Almeida Filho } 3471677e90edSThomas Graf return 0; 3472aeb193eaSWedson Almeida Filho } 3473677e90edSThomas Graf 3474677e90edSThomas Graf next_skb: 347595e3b24cSHerbert Xu block_limit = skb_headlen(st->cur_skb) + st->stepped_offset; 3476677e90edSThomas Graf 3477995b3379SThomas Chenault if (abs_offset < block_limit && !st->frag_data) { 347895e3b24cSHerbert Xu *data = st->cur_skb->data + (abs_offset - st->stepped_offset); 3479677e90edSThomas Graf return block_limit - abs_offset; 3480677e90edSThomas Graf } 3481677e90edSThomas Graf 3482677e90edSThomas Graf if (st->frag_idx == 0 && !st->frag_data) 3483677e90edSThomas Graf st->stepped_offset += skb_headlen(st->cur_skb); 3484677e90edSThomas Graf 3485677e90edSThomas Graf while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { 3486677e90edSThomas Graf frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; 34879e903e08SEric Dumazet block_limit = skb_frag_size(frag) + st->stepped_offset; 3488677e90edSThomas Graf 3489677e90edSThomas Graf if (abs_offset < block_limit) { 3490677e90edSThomas Graf if (!st->frag_data) 349151c56b00SEric Dumazet st->frag_data = kmap_atomic(skb_frag_page(frag)); 3492677e90edSThomas Graf 3493b54c9d5bSJonathan Lemon *data = (u8 *) st->frag_data + skb_frag_off(frag) + 3494677e90edSThomas Graf (abs_offset - st->stepped_offset); 3495677e90edSThomas Graf 3496677e90edSThomas Graf return block_limit - abs_offset; 3497677e90edSThomas Graf } 3498677e90edSThomas Graf 3499677e90edSThomas Graf if (st->frag_data) { 350051c56b00SEric Dumazet kunmap_atomic(st->frag_data); 3501677e90edSThomas Graf st->frag_data = NULL; 3502677e90edSThomas Graf } 3503677e90edSThomas Graf 3504677e90edSThomas Graf st->frag_idx++; 35059e903e08SEric Dumazet st->stepped_offset += skb_frag_size(frag); 3506677e90edSThomas Graf } 3507677e90edSThomas Graf 35085b5a60daSOlaf Kirch if (st->frag_data) { 350951c56b00SEric Dumazet kunmap_atomic(st->frag_data); 35105b5a60daSOlaf Kirch st->frag_data = NULL; 35115b5a60daSOlaf Kirch } 35125b5a60daSOlaf Kirch 351321dc3301SDavid S. Miller if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) { 3514677e90edSThomas Graf st->cur_skb = skb_shinfo(st->root_skb)->frag_list; 351595e3b24cSHerbert Xu st->frag_idx = 0; 3516677e90edSThomas Graf goto next_skb; 351771b3346dSShyam Iyer } else if (st->cur_skb->next) { 351871b3346dSShyam Iyer st->cur_skb = st->cur_skb->next; 351971b3346dSShyam Iyer st->frag_idx = 0; 3520677e90edSThomas Graf goto next_skb; 3521677e90edSThomas Graf } 3522677e90edSThomas Graf 3523677e90edSThomas Graf return 0; 3524677e90edSThomas Graf } 3525b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_seq_read); 3526677e90edSThomas Graf 3527677e90edSThomas Graf /** 3528677e90edSThomas Graf * skb_abort_seq_read - Abort a sequential read of skb data 3529677e90edSThomas Graf * @st: state variable 3530677e90edSThomas Graf * 3531677e90edSThomas Graf * Must be called if skb_seq_read() was not called until it 3532677e90edSThomas Graf * returned 0. 3533677e90edSThomas Graf */ 3534677e90edSThomas Graf void skb_abort_seq_read(struct skb_seq_state *st) 3535677e90edSThomas Graf { 3536677e90edSThomas Graf if (st->frag_data) 353751c56b00SEric Dumazet kunmap_atomic(st->frag_data); 3538677e90edSThomas Graf } 3539b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_abort_seq_read); 3540677e90edSThomas Graf 35413fc7e8a6SThomas Graf #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) 35423fc7e8a6SThomas Graf 35433fc7e8a6SThomas Graf static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, 35443fc7e8a6SThomas Graf struct ts_config *conf, 35453fc7e8a6SThomas Graf struct ts_state *state) 35463fc7e8a6SThomas Graf { 35473fc7e8a6SThomas Graf return skb_seq_read(offset, text, TS_SKB_CB(state)); 35483fc7e8a6SThomas Graf } 35493fc7e8a6SThomas Graf 35503fc7e8a6SThomas Graf static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) 35513fc7e8a6SThomas Graf { 35523fc7e8a6SThomas Graf skb_abort_seq_read(TS_SKB_CB(state)); 35533fc7e8a6SThomas Graf } 35543fc7e8a6SThomas Graf 35553fc7e8a6SThomas Graf /** 35563fc7e8a6SThomas Graf * skb_find_text - Find a text pattern in skb data 35573fc7e8a6SThomas Graf * @skb: the buffer to look in 35583fc7e8a6SThomas Graf * @from: search offset 35593fc7e8a6SThomas Graf * @to: search limit 35603fc7e8a6SThomas Graf * @config: textsearch configuration 35613fc7e8a6SThomas Graf * 35623fc7e8a6SThomas Graf * Finds a pattern in the skb data according to the specified 35633fc7e8a6SThomas Graf * textsearch configuration. Use textsearch_next() to retrieve 35643fc7e8a6SThomas Graf * subsequent occurrences of the pattern. Returns the offset 35653fc7e8a6SThomas Graf * to the first occurrence or UINT_MAX if no match was found. 35663fc7e8a6SThomas Graf */ 35673fc7e8a6SThomas Graf unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 3568059a2440SBojan Prtvar unsigned int to, struct ts_config *config) 35693fc7e8a6SThomas Graf { 3570059a2440SBojan Prtvar struct ts_state state; 3571f72b948dSPhil Oester unsigned int ret; 3572f72b948dSPhil Oester 35733fc7e8a6SThomas Graf config->get_next_block = skb_ts_get_next_block; 35743fc7e8a6SThomas Graf config->finish = skb_ts_finish; 35753fc7e8a6SThomas Graf 3576059a2440SBojan Prtvar skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state)); 35773fc7e8a6SThomas Graf 3578059a2440SBojan Prtvar ret = textsearch_find(config, &state); 3579f72b948dSPhil Oester return (ret <= to - from ? ret : UINT_MAX); 35803fc7e8a6SThomas Graf } 3581b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_find_text); 35823fc7e8a6SThomas Graf 3583be12a1feSHannes Frederic Sowa int skb_append_pagefrags(struct sk_buff *skb, struct page *page, 3584be12a1feSHannes Frederic Sowa int offset, size_t size) 3585be12a1feSHannes Frederic Sowa { 3586be12a1feSHannes Frederic Sowa int i = skb_shinfo(skb)->nr_frags; 3587be12a1feSHannes Frederic Sowa 3588be12a1feSHannes Frederic Sowa if (skb_can_coalesce(skb, i, page, offset)) { 3589be12a1feSHannes Frederic Sowa skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size); 3590be12a1feSHannes Frederic Sowa } else if (i < MAX_SKB_FRAGS) { 3591be12a1feSHannes Frederic Sowa get_page(page); 3592be12a1feSHannes Frederic Sowa skb_fill_page_desc(skb, i, page, offset, size); 3593be12a1feSHannes Frederic Sowa } else { 3594be12a1feSHannes Frederic Sowa return -EMSGSIZE; 3595be12a1feSHannes Frederic Sowa } 3596be12a1feSHannes Frederic Sowa 3597be12a1feSHannes Frederic Sowa return 0; 3598be12a1feSHannes Frederic Sowa } 3599be12a1feSHannes Frederic Sowa EXPORT_SYMBOL_GPL(skb_append_pagefrags); 3600be12a1feSHannes Frederic Sowa 3601cbb042f9SHerbert Xu /** 3602cbb042f9SHerbert Xu * skb_pull_rcsum - pull skb and update receive checksum 3603cbb042f9SHerbert Xu * @skb: buffer to update 3604cbb042f9SHerbert Xu * @len: length of data pulled 3605cbb042f9SHerbert Xu * 3606cbb042f9SHerbert Xu * This function performs an skb_pull on the packet and updates 3607fee54fa5SUrs Thuermann * the CHECKSUM_COMPLETE checksum. It should be used on 360884fa7933SPatrick McHardy * receive path processing instead of skb_pull unless you know 360984fa7933SPatrick McHardy * that the checksum difference is zero (e.g., a valid IP header) 361084fa7933SPatrick McHardy * or you are setting ip_summed to CHECKSUM_NONE. 3611cbb042f9SHerbert Xu */ 3612af72868bSJohannes Berg void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) 3613cbb042f9SHerbert Xu { 361431b33dfbSPravin B Shelar unsigned char *data = skb->data; 361531b33dfbSPravin B Shelar 3616cbb042f9SHerbert Xu BUG_ON(len > skb->len); 361731b33dfbSPravin B Shelar __skb_pull(skb, len); 361831b33dfbSPravin B Shelar skb_postpull_rcsum(skb, data, len); 361931b33dfbSPravin B Shelar return skb->data; 3620cbb042f9SHerbert Xu } 3621f94691acSArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(skb_pull_rcsum); 3622f94691acSArnaldo Carvalho de Melo 362313acc94eSYonghong Song static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb) 362413acc94eSYonghong Song { 362513acc94eSYonghong Song skb_frag_t head_frag; 362613acc94eSYonghong Song struct page *page; 362713acc94eSYonghong Song 362813acc94eSYonghong Song page = virt_to_head_page(frag_skb->head); 3629d8e18a51SMatthew Wilcox (Oracle) __skb_frag_set_page(&head_frag, page); 3630b54c9d5bSJonathan Lemon skb_frag_off_set(&head_frag, frag_skb->data - 3631b54c9d5bSJonathan Lemon (unsigned char *)page_address(page)); 3632d8e18a51SMatthew Wilcox (Oracle) skb_frag_size_set(&head_frag, skb_headlen(frag_skb)); 363313acc94eSYonghong Song return head_frag; 363413acc94eSYonghong Song } 363513acc94eSYonghong Song 36363a1296a3SSteffen Klassert struct sk_buff *skb_segment_list(struct sk_buff *skb, 36373a1296a3SSteffen Klassert netdev_features_t features, 36383a1296a3SSteffen Klassert unsigned int offset) 36393a1296a3SSteffen Klassert { 36403a1296a3SSteffen Klassert struct sk_buff *list_skb = skb_shinfo(skb)->frag_list; 36413a1296a3SSteffen Klassert unsigned int tnl_hlen = skb_tnl_header_len(skb); 36423a1296a3SSteffen Klassert unsigned int delta_truesize = 0; 36433a1296a3SSteffen Klassert unsigned int delta_len = 0; 36443a1296a3SSteffen Klassert struct sk_buff *tail = NULL; 36453a1296a3SSteffen Klassert struct sk_buff *nskb; 36463a1296a3SSteffen Klassert 36473a1296a3SSteffen Klassert skb_push(skb, -skb_network_offset(skb) + offset); 36483a1296a3SSteffen Klassert 36493a1296a3SSteffen Klassert skb_shinfo(skb)->frag_list = NULL; 36503a1296a3SSteffen Klassert 36513a1296a3SSteffen Klassert do { 36523a1296a3SSteffen Klassert nskb = list_skb; 36533a1296a3SSteffen Klassert list_skb = list_skb->next; 36543a1296a3SSteffen Klassert 36553a1296a3SSteffen Klassert if (!tail) 36563a1296a3SSteffen Klassert skb->next = nskb; 36573a1296a3SSteffen Klassert else 36583a1296a3SSteffen Klassert tail->next = nskb; 36593a1296a3SSteffen Klassert 36603a1296a3SSteffen Klassert tail = nskb; 36613a1296a3SSteffen Klassert 36623a1296a3SSteffen Klassert delta_len += nskb->len; 36633a1296a3SSteffen Klassert delta_truesize += nskb->truesize; 36643a1296a3SSteffen Klassert 36653a1296a3SSteffen Klassert skb_push(nskb, -skb_network_offset(nskb) + offset); 36663a1296a3SSteffen Klassert 3667cf673ed0SFlorian Westphal skb_release_head_state(nskb); 36683a1296a3SSteffen Klassert __copy_skb_header(nskb, skb); 36693a1296a3SSteffen Klassert 36703a1296a3SSteffen Klassert skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb)); 36713a1296a3SSteffen Klassert skb_copy_from_linear_data_offset(skb, -tnl_hlen, 36723a1296a3SSteffen Klassert nskb->data - tnl_hlen, 36733a1296a3SSteffen Klassert offset + tnl_hlen); 36743a1296a3SSteffen Klassert 36753a1296a3SSteffen Klassert if (skb_needs_linearize(nskb, features) && 36763a1296a3SSteffen Klassert __skb_linearize(nskb)) 36773a1296a3SSteffen Klassert goto err_linearize; 36783a1296a3SSteffen Klassert 36793a1296a3SSteffen Klassert } while (list_skb); 36803a1296a3SSteffen Klassert 36813a1296a3SSteffen Klassert skb->truesize = skb->truesize - delta_truesize; 36823a1296a3SSteffen Klassert skb->data_len = skb->data_len - delta_len; 36833a1296a3SSteffen Klassert skb->len = skb->len - delta_len; 36843a1296a3SSteffen Klassert 36853a1296a3SSteffen Klassert skb_gso_reset(skb); 36863a1296a3SSteffen Klassert 36873a1296a3SSteffen Klassert skb->prev = tail; 36883a1296a3SSteffen Klassert 36893a1296a3SSteffen Klassert if (skb_needs_linearize(skb, features) && 36903a1296a3SSteffen Klassert __skb_linearize(skb)) 36913a1296a3SSteffen Klassert goto err_linearize; 36923a1296a3SSteffen Klassert 36933a1296a3SSteffen Klassert skb_get(skb); 36943a1296a3SSteffen Klassert 36953a1296a3SSteffen Klassert return skb; 36963a1296a3SSteffen Klassert 36973a1296a3SSteffen Klassert err_linearize: 36983a1296a3SSteffen Klassert kfree_skb_list(skb->next); 36993a1296a3SSteffen Klassert skb->next = NULL; 37003a1296a3SSteffen Klassert return ERR_PTR(-ENOMEM); 37013a1296a3SSteffen Klassert } 37023a1296a3SSteffen Klassert EXPORT_SYMBOL_GPL(skb_segment_list); 37033a1296a3SSteffen Klassert 37043a1296a3SSteffen Klassert int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb) 37053a1296a3SSteffen Klassert { 37063a1296a3SSteffen Klassert if (unlikely(p->len + skb->len >= 65536)) 37073a1296a3SSteffen Klassert return -E2BIG; 37083a1296a3SSteffen Klassert 37093a1296a3SSteffen Klassert if (NAPI_GRO_CB(p)->last == p) 37103a1296a3SSteffen Klassert skb_shinfo(p)->frag_list = skb; 37113a1296a3SSteffen Klassert else 37123a1296a3SSteffen Klassert NAPI_GRO_CB(p)->last->next = skb; 37133a1296a3SSteffen Klassert 37143a1296a3SSteffen Klassert skb_pull(skb, skb_gro_offset(skb)); 37153a1296a3SSteffen Klassert 37163a1296a3SSteffen Klassert NAPI_GRO_CB(p)->last = skb; 37173a1296a3SSteffen Klassert NAPI_GRO_CB(p)->count++; 37183a1296a3SSteffen Klassert p->data_len += skb->len; 37193a1296a3SSteffen Klassert p->truesize += skb->truesize; 37203a1296a3SSteffen Klassert p->len += skb->len; 37213a1296a3SSteffen Klassert 37223a1296a3SSteffen Klassert NAPI_GRO_CB(skb)->same_flow = 1; 37233a1296a3SSteffen Klassert 37243a1296a3SSteffen Klassert return 0; 37253a1296a3SSteffen Klassert } 37263a1296a3SSteffen Klassert 3727f4c50d99SHerbert Xu /** 3728f4c50d99SHerbert Xu * skb_segment - Perform protocol segmentation on skb. 3729df5771ffSMichael S. Tsirkin * @head_skb: buffer to segment 3730576a30ebSHerbert Xu * @features: features for the output path (see dev->features) 3731f4c50d99SHerbert Xu * 3732f4c50d99SHerbert Xu * This function performs segmentation on the given skb. It returns 37334c821d75SBen Hutchings * a pointer to the first in a list of new skbs for the segments. 37344c821d75SBen Hutchings * In case of error it returns ERR_PTR(err). 3735f4c50d99SHerbert Xu */ 3736df5771ffSMichael S. Tsirkin struct sk_buff *skb_segment(struct sk_buff *head_skb, 3737df5771ffSMichael S. Tsirkin netdev_features_t features) 3738f4c50d99SHerbert Xu { 3739f4c50d99SHerbert Xu struct sk_buff *segs = NULL; 3740f4c50d99SHerbert Xu struct sk_buff *tail = NULL; 37411a4cedafSMichael S. Tsirkin struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list; 3742df5771ffSMichael S. Tsirkin skb_frag_t *frag = skb_shinfo(head_skb)->frags; 3743df5771ffSMichael S. Tsirkin unsigned int mss = skb_shinfo(head_skb)->gso_size; 3744df5771ffSMichael S. Tsirkin unsigned int doffset = head_skb->data - skb_mac_header(head_skb); 37451fd819ecSMichael S. Tsirkin struct sk_buff *frag_skb = head_skb; 3746f4c50d99SHerbert Xu unsigned int offset = doffset; 3747df5771ffSMichael S. Tsirkin unsigned int tnl_hlen = skb_tnl_header_len(head_skb); 3748802ab55aSAlexander Duyck unsigned int partial_segs = 0; 3749f4c50d99SHerbert Xu unsigned int headroom; 3750802ab55aSAlexander Duyck unsigned int len = head_skb->len; 3751ec5f0615SPravin B Shelar __be16 proto; 375236c98382SAlexander Duyck bool csum, sg; 3753df5771ffSMichael S. Tsirkin int nfrags = skb_shinfo(head_skb)->nr_frags; 3754f4c50d99SHerbert Xu int err = -ENOMEM; 3755f4c50d99SHerbert Xu int i = 0; 3756f4c50d99SHerbert Xu int pos; 3757f4c50d99SHerbert Xu 37583dcbdb13SShmulik Ladkani if (list_skb && !list_skb->head_frag && skb_headlen(list_skb) && 37593dcbdb13SShmulik Ladkani (skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY)) { 37603dcbdb13SShmulik Ladkani /* gso_size is untrusted, and we have a frag_list with a linear 37613dcbdb13SShmulik Ladkani * non head_frag head. 37623dcbdb13SShmulik Ladkani * 37633dcbdb13SShmulik Ladkani * (we assume checking the first list_skb member suffices; 37643dcbdb13SShmulik Ladkani * i.e if either of the list_skb members have non head_frag 37653dcbdb13SShmulik Ladkani * head, then the first one has too). 37663dcbdb13SShmulik Ladkani * 37673dcbdb13SShmulik Ladkani * If head_skb's headlen does not fit requested gso_size, it 37683dcbdb13SShmulik Ladkani * means that the frag_list members do NOT terminate on exact 37693dcbdb13SShmulik Ladkani * gso_size boundaries. Hence we cannot perform skb_frag_t page 37703dcbdb13SShmulik Ladkani * sharing. Therefore we must fallback to copying the frag_list 37713dcbdb13SShmulik Ladkani * skbs; we do so by disabling SG. 37723dcbdb13SShmulik Ladkani */ 37733dcbdb13SShmulik Ladkani if (mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb)) 37743dcbdb13SShmulik Ladkani features &= ~NETIF_F_SG; 37753dcbdb13SShmulik Ladkani } 37763dcbdb13SShmulik Ladkani 37775882a07cSWei-Chun Chao __skb_push(head_skb, doffset); 37782f631133SMiaohe Lin proto = skb_network_protocol(head_skb, NULL); 3779ec5f0615SPravin B Shelar if (unlikely(!proto)) 3780ec5f0615SPravin B Shelar return ERR_PTR(-EINVAL); 3781ec5f0615SPravin B Shelar 378236c98382SAlexander Duyck sg = !!(features & NETIF_F_SG); 3783f245d079SAlexander Duyck csum = !!can_checksum_protocol(features, proto); 37847e2b10c1STom Herbert 378507b26c94SSteffen Klassert if (sg && csum && (mss != GSO_BY_FRAGS)) { 378607b26c94SSteffen Klassert if (!(features & NETIF_F_GSO_PARTIAL)) { 378707b26c94SSteffen Klassert struct sk_buff *iter; 378843170c4eSIlan Tayari unsigned int frag_len; 378907b26c94SSteffen Klassert 379007b26c94SSteffen Klassert if (!list_skb || 379107b26c94SSteffen Klassert !net_gso_ok(features, skb_shinfo(head_skb)->gso_type)) 379207b26c94SSteffen Klassert goto normal; 379307b26c94SSteffen Klassert 379443170c4eSIlan Tayari /* If we get here then all the required 379543170c4eSIlan Tayari * GSO features except frag_list are supported. 379643170c4eSIlan Tayari * Try to split the SKB to multiple GSO SKBs 379743170c4eSIlan Tayari * with no frag_list. 379843170c4eSIlan Tayari * Currently we can do that only when the buffers don't 379943170c4eSIlan Tayari * have a linear part and all the buffers except 380043170c4eSIlan Tayari * the last are of the same length. 380107b26c94SSteffen Klassert */ 380243170c4eSIlan Tayari frag_len = list_skb->len; 380307b26c94SSteffen Klassert skb_walk_frags(head_skb, iter) { 380443170c4eSIlan Tayari if (frag_len != iter->len && iter->next) 380543170c4eSIlan Tayari goto normal; 3806eaffadbbSIlan Tayari if (skb_headlen(iter) && !iter->head_frag) 380707b26c94SSteffen Klassert goto normal; 380807b26c94SSteffen Klassert 380907b26c94SSteffen Klassert len -= iter->len; 381007b26c94SSteffen Klassert } 381143170c4eSIlan Tayari 381243170c4eSIlan Tayari if (len != frag_len) 381343170c4eSIlan Tayari goto normal; 381407b26c94SSteffen Klassert } 381507b26c94SSteffen Klassert 3816802ab55aSAlexander Duyck /* GSO partial only requires that we trim off any excess that 3817802ab55aSAlexander Duyck * doesn't fit into an MSS sized block, so take care of that 3818802ab55aSAlexander Duyck * now. 3819802ab55aSAlexander Duyck */ 3820802ab55aSAlexander Duyck partial_segs = len / mss; 3821d7fb5a80SAlexander Duyck if (partial_segs > 1) 3822802ab55aSAlexander Duyck mss *= partial_segs; 3823d7fb5a80SAlexander Duyck else 3824d7fb5a80SAlexander Duyck partial_segs = 0; 3825802ab55aSAlexander Duyck } 3826802ab55aSAlexander Duyck 382707b26c94SSteffen Klassert normal: 3828df5771ffSMichael S. Tsirkin headroom = skb_headroom(head_skb); 3829df5771ffSMichael S. Tsirkin pos = skb_headlen(head_skb); 3830f4c50d99SHerbert Xu 3831f4c50d99SHerbert Xu do { 3832f4c50d99SHerbert Xu struct sk_buff *nskb; 38338cb19905SMichael S. Tsirkin skb_frag_t *nskb_frag; 3834c8884eddSHerbert Xu int hsize; 3835f4c50d99SHerbert Xu int size; 3836f4c50d99SHerbert Xu 38373953c46cSMarcelo Ricardo Leitner if (unlikely(mss == GSO_BY_FRAGS)) { 38383953c46cSMarcelo Ricardo Leitner len = list_skb->len; 38393953c46cSMarcelo Ricardo Leitner } else { 3840df5771ffSMichael S. Tsirkin len = head_skb->len - offset; 3841f4c50d99SHerbert Xu if (len > mss) 3842f4c50d99SHerbert Xu len = mss; 38433953c46cSMarcelo Ricardo Leitner } 3844f4c50d99SHerbert Xu 3845df5771ffSMichael S. Tsirkin hsize = skb_headlen(head_skb) - offset; 3846f4c50d99SHerbert Xu if (hsize < 0) 3847f4c50d99SHerbert Xu hsize = 0; 3848c8884eddSHerbert Xu if (hsize > len || !sg) 3849c8884eddSHerbert Xu hsize = len; 3850f4c50d99SHerbert Xu 38511a4cedafSMichael S. Tsirkin if (!hsize && i >= nfrags && skb_headlen(list_skb) && 38521a4cedafSMichael S. Tsirkin (skb_headlen(list_skb) == len || sg)) { 38531a4cedafSMichael S. Tsirkin BUG_ON(skb_headlen(list_skb) > len); 385489319d38SHerbert Xu 38559d8506ccSHerbert Xu i = 0; 38561a4cedafSMichael S. Tsirkin nfrags = skb_shinfo(list_skb)->nr_frags; 38571a4cedafSMichael S. Tsirkin frag = skb_shinfo(list_skb)->frags; 38581fd819ecSMichael S. Tsirkin frag_skb = list_skb; 38591a4cedafSMichael S. Tsirkin pos += skb_headlen(list_skb); 38609d8506ccSHerbert Xu 38619d8506ccSHerbert Xu while (pos < offset + len) { 38629d8506ccSHerbert Xu BUG_ON(i >= nfrags); 38639d8506ccSHerbert Xu 38644e1beba1SMichael S. Tsirkin size = skb_frag_size(frag); 38659d8506ccSHerbert Xu if (pos + size > offset + len) 38669d8506ccSHerbert Xu break; 38679d8506ccSHerbert Xu 38689d8506ccSHerbert Xu i++; 38699d8506ccSHerbert Xu pos += size; 38704e1beba1SMichael S. Tsirkin frag++; 38719d8506ccSHerbert Xu } 38729d8506ccSHerbert Xu 38731a4cedafSMichael S. Tsirkin nskb = skb_clone(list_skb, GFP_ATOMIC); 38741a4cedafSMichael S. Tsirkin list_skb = list_skb->next; 387589319d38SHerbert Xu 3876f4c50d99SHerbert Xu if (unlikely(!nskb)) 3877f4c50d99SHerbert Xu goto err; 3878f4c50d99SHerbert Xu 38799d8506ccSHerbert Xu if (unlikely(pskb_trim(nskb, len))) { 38809d8506ccSHerbert Xu kfree_skb(nskb); 38819d8506ccSHerbert Xu goto err; 38829d8506ccSHerbert Xu } 38839d8506ccSHerbert Xu 3884ec47ea82SAlexander Duyck hsize = skb_end_offset(nskb); 388589319d38SHerbert Xu if (skb_cow_head(nskb, doffset + headroom)) { 388689319d38SHerbert Xu kfree_skb(nskb); 388789319d38SHerbert Xu goto err; 388889319d38SHerbert Xu } 388989319d38SHerbert Xu 3890ec47ea82SAlexander Duyck nskb->truesize += skb_end_offset(nskb) - hsize; 389189319d38SHerbert Xu skb_release_head_state(nskb); 389289319d38SHerbert Xu __skb_push(nskb, doffset); 389389319d38SHerbert Xu } else { 3894c93bdd0eSMel Gorman nskb = __alloc_skb(hsize + doffset + headroom, 3895df5771ffSMichael S. Tsirkin GFP_ATOMIC, skb_alloc_rx_flag(head_skb), 3896c93bdd0eSMel Gorman NUMA_NO_NODE); 389789319d38SHerbert Xu 389889319d38SHerbert Xu if (unlikely(!nskb)) 389989319d38SHerbert Xu goto err; 390089319d38SHerbert Xu 390189319d38SHerbert Xu skb_reserve(nskb, headroom); 390289319d38SHerbert Xu __skb_put(nskb, doffset); 390389319d38SHerbert Xu } 390489319d38SHerbert Xu 3905f4c50d99SHerbert Xu if (segs) 3906f4c50d99SHerbert Xu tail->next = nskb; 3907f4c50d99SHerbert Xu else 3908f4c50d99SHerbert Xu segs = nskb; 3909f4c50d99SHerbert Xu tail = nskb; 3910f4c50d99SHerbert Xu 3911df5771ffSMichael S. Tsirkin __copy_skb_header(nskb, head_skb); 3912f4c50d99SHerbert Xu 3913030737bcSEric Dumazet skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom); 3914fcdfe3a7SVlad Yasevich skb_reset_mac_len(nskb); 391568c33163SPravin B Shelar 3916df5771ffSMichael S. Tsirkin skb_copy_from_linear_data_offset(head_skb, -tnl_hlen, 391768c33163SPravin B Shelar nskb->data - tnl_hlen, 391868c33163SPravin B Shelar doffset + tnl_hlen); 391989319d38SHerbert Xu 39209d8506ccSHerbert Xu if (nskb->len == len + doffset) 39211cdbcb79SSimon Horman goto perform_csum_check; 392289319d38SHerbert Xu 39237fbeffedSAlexander Duyck if (!sg) { 39241454c9faSYadu Kishore if (!csum) { 39257fbeffedSAlexander Duyck if (!nskb->remcsum_offload) 39266f85a124SHerbert Xu nskb->ip_summed = CHECKSUM_NONE; 392776443456SAlexander Duyck SKB_GSO_CB(nskb)->csum = 392876443456SAlexander Duyck skb_copy_and_csum_bits(head_skb, offset, 39291454c9faSYadu Kishore skb_put(nskb, 39301454c9faSYadu Kishore len), 39318d5930dfSAl Viro len); 39327e2b10c1STom Herbert SKB_GSO_CB(nskb)->csum_start = 3933de843723STom Herbert skb_headroom(nskb) + doffset; 39341454c9faSYadu Kishore } else { 39351454c9faSYadu Kishore skb_copy_bits(head_skb, offset, 39361454c9faSYadu Kishore skb_put(nskb, len), 39371454c9faSYadu Kishore len); 39381454c9faSYadu Kishore } 3939f4c50d99SHerbert Xu continue; 3940f4c50d99SHerbert Xu } 3941f4c50d99SHerbert Xu 39428cb19905SMichael S. Tsirkin nskb_frag = skb_shinfo(nskb)->frags; 3943f4c50d99SHerbert Xu 3944df5771ffSMichael S. Tsirkin skb_copy_from_linear_data_offset(head_skb, offset, 3945d626f62bSArnaldo Carvalho de Melo skb_put(nskb, hsize), hsize); 3946f4c50d99SHerbert Xu 3947fff88030SWillem de Bruijn skb_shinfo(nskb)->tx_flags |= skb_shinfo(head_skb)->tx_flags & 3948df5771ffSMichael S. Tsirkin SKBTX_SHARED_FRAG; 3949cef401deSEric Dumazet 3950bf5c25d6SWillem de Bruijn if (skb_orphan_frags(frag_skb, GFP_ATOMIC) || 3951bf5c25d6SWillem de Bruijn skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC)) 3952bf5c25d6SWillem de Bruijn goto err; 3953bf5c25d6SWillem de Bruijn 39549d8506ccSHerbert Xu while (pos < offset + len) { 39559d8506ccSHerbert Xu if (i >= nfrags) { 39569d8506ccSHerbert Xu i = 0; 39571a4cedafSMichael S. Tsirkin nfrags = skb_shinfo(list_skb)->nr_frags; 39581a4cedafSMichael S. Tsirkin frag = skb_shinfo(list_skb)->frags; 39591fd819ecSMichael S. Tsirkin frag_skb = list_skb; 396013acc94eSYonghong Song if (!skb_headlen(list_skb)) { 39619d8506ccSHerbert Xu BUG_ON(!nfrags); 396213acc94eSYonghong Song } else { 396313acc94eSYonghong Song BUG_ON(!list_skb->head_frag); 39649d8506ccSHerbert Xu 396513acc94eSYonghong Song /* to make room for head_frag. */ 396613acc94eSYonghong Song i--; 396713acc94eSYonghong Song frag--; 396813acc94eSYonghong Song } 3969bf5c25d6SWillem de Bruijn if (skb_orphan_frags(frag_skb, GFP_ATOMIC) || 3970bf5c25d6SWillem de Bruijn skb_zerocopy_clone(nskb, frag_skb, 3971bf5c25d6SWillem de Bruijn GFP_ATOMIC)) 3972bf5c25d6SWillem de Bruijn goto err; 3973bf5c25d6SWillem de Bruijn 39741a4cedafSMichael S. Tsirkin list_skb = list_skb->next; 39759d8506ccSHerbert Xu } 39769d8506ccSHerbert Xu 39779d8506ccSHerbert Xu if (unlikely(skb_shinfo(nskb)->nr_frags >= 39789d8506ccSHerbert Xu MAX_SKB_FRAGS)) { 39799d8506ccSHerbert Xu net_warn_ratelimited( 39809d8506ccSHerbert Xu "skb_segment: too many frags: %u %u\n", 39819d8506ccSHerbert Xu pos, mss); 3982ff907a11SEric Dumazet err = -EINVAL; 39839d8506ccSHerbert Xu goto err; 39849d8506ccSHerbert Xu } 39859d8506ccSHerbert Xu 398613acc94eSYonghong Song *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag; 39878cb19905SMichael S. Tsirkin __skb_frag_ref(nskb_frag); 39888cb19905SMichael S. Tsirkin size = skb_frag_size(nskb_frag); 3989f4c50d99SHerbert Xu 3990f4c50d99SHerbert Xu if (pos < offset) { 3991b54c9d5bSJonathan Lemon skb_frag_off_add(nskb_frag, offset - pos); 39928cb19905SMichael S. Tsirkin skb_frag_size_sub(nskb_frag, offset - pos); 3993f4c50d99SHerbert Xu } 3994f4c50d99SHerbert Xu 399589319d38SHerbert Xu skb_shinfo(nskb)->nr_frags++; 3996f4c50d99SHerbert Xu 3997f4c50d99SHerbert Xu if (pos + size <= offset + len) { 3998f4c50d99SHerbert Xu i++; 39994e1beba1SMichael S. Tsirkin frag++; 4000f4c50d99SHerbert Xu pos += size; 4001f4c50d99SHerbert Xu } else { 40028cb19905SMichael S. Tsirkin skb_frag_size_sub(nskb_frag, pos + size - (offset + len)); 400389319d38SHerbert Xu goto skip_fraglist; 4004f4c50d99SHerbert Xu } 4005f4c50d99SHerbert Xu 40068cb19905SMichael S. Tsirkin nskb_frag++; 4007f4c50d99SHerbert Xu } 4008f4c50d99SHerbert Xu 400989319d38SHerbert Xu skip_fraglist: 4010f4c50d99SHerbert Xu nskb->data_len = len - hsize; 4011f4c50d99SHerbert Xu nskb->len += nskb->data_len; 4012f4c50d99SHerbert Xu nskb->truesize += nskb->data_len; 4013ec5f0615SPravin B Shelar 40141cdbcb79SSimon Horman perform_csum_check: 40157fbeffedSAlexander Duyck if (!csum) { 4016ff907a11SEric Dumazet if (skb_has_shared_frag(nskb) && 4017ff907a11SEric Dumazet __skb_linearize(nskb)) 4018ddff00d4SAlexander Duyck goto err; 4019ff907a11SEric Dumazet 40207fbeffedSAlexander Duyck if (!nskb->remcsum_offload) 4021ec5f0615SPravin B Shelar nskb->ip_summed = CHECKSUM_NONE; 402276443456SAlexander Duyck SKB_GSO_CB(nskb)->csum = 402376443456SAlexander Duyck skb_checksum(nskb, doffset, 402476443456SAlexander Duyck nskb->len - doffset, 0); 40257e2b10c1STom Herbert SKB_GSO_CB(nskb)->csum_start = 40267e2b10c1STom Herbert skb_headroom(nskb) + doffset; 4027ec5f0615SPravin B Shelar } 4028df5771ffSMichael S. Tsirkin } while ((offset += len) < head_skb->len); 4029f4c50d99SHerbert Xu 4030bec3cfdcSEric Dumazet /* Some callers want to get the end of the list. 4031bec3cfdcSEric Dumazet * Put it in segs->prev to avoid walking the list. 4032bec3cfdcSEric Dumazet * (see validate_xmit_skb_list() for example) 4033bec3cfdcSEric Dumazet */ 4034bec3cfdcSEric Dumazet segs->prev = tail; 4035432c856fSToshiaki Makita 4036802ab55aSAlexander Duyck if (partial_segs) { 403707b26c94SSteffen Klassert struct sk_buff *iter; 4038802ab55aSAlexander Duyck int type = skb_shinfo(head_skb)->gso_type; 403907b26c94SSteffen Klassert unsigned short gso_size = skb_shinfo(head_skb)->gso_size; 4040802ab55aSAlexander Duyck 4041802ab55aSAlexander Duyck /* Update type to add partial and then remove dodgy if set */ 404207b26c94SSteffen Klassert type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL; 4043802ab55aSAlexander Duyck type &= ~SKB_GSO_DODGY; 4044802ab55aSAlexander Duyck 4045802ab55aSAlexander Duyck /* Update GSO info and prepare to start updating headers on 4046802ab55aSAlexander Duyck * our way back down the stack of protocols. 4047802ab55aSAlexander Duyck */ 404807b26c94SSteffen Klassert for (iter = segs; iter; iter = iter->next) { 404907b26c94SSteffen Klassert skb_shinfo(iter)->gso_size = gso_size; 405007b26c94SSteffen Klassert skb_shinfo(iter)->gso_segs = partial_segs; 405107b26c94SSteffen Klassert skb_shinfo(iter)->gso_type = type; 405207b26c94SSteffen Klassert SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset; 405307b26c94SSteffen Klassert } 405407b26c94SSteffen Klassert 405507b26c94SSteffen Klassert if (tail->len - doffset <= gso_size) 405607b26c94SSteffen Klassert skb_shinfo(tail)->gso_size = 0; 405707b26c94SSteffen Klassert else if (tail != segs) 405807b26c94SSteffen Klassert skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size); 4059802ab55aSAlexander Duyck } 4060802ab55aSAlexander Duyck 4061432c856fSToshiaki Makita /* Following permits correct backpressure, for protocols 4062432c856fSToshiaki Makita * using skb_set_owner_w(). 4063432c856fSToshiaki Makita * Idea is to tranfert ownership from head_skb to last segment. 4064432c856fSToshiaki Makita */ 4065432c856fSToshiaki Makita if (head_skb->destructor == sock_wfree) { 4066432c856fSToshiaki Makita swap(tail->truesize, head_skb->truesize); 4067432c856fSToshiaki Makita swap(tail->destructor, head_skb->destructor); 4068432c856fSToshiaki Makita swap(tail->sk, head_skb->sk); 4069432c856fSToshiaki Makita } 4070f4c50d99SHerbert Xu return segs; 4071f4c50d99SHerbert Xu 4072f4c50d99SHerbert Xu err: 4073289dccbeSEric Dumazet kfree_skb_list(segs); 4074f4c50d99SHerbert Xu return ERR_PTR(err); 4075f4c50d99SHerbert Xu } 4076f4c50d99SHerbert Xu EXPORT_SYMBOL_GPL(skb_segment); 4077f4c50d99SHerbert Xu 4078d4546c25SDavid Miller int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) 407971d93b39SHerbert Xu { 40808a29111cSEric Dumazet struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); 408167147ba9SHerbert Xu unsigned int offset = skb_gro_offset(skb); 408267147ba9SHerbert Xu unsigned int headlen = skb_headlen(skb); 40838a29111cSEric Dumazet unsigned int len = skb_gro_len(skb); 4084715dc1f3SEric Dumazet unsigned int delta_truesize; 4085d4546c25SDavid Miller struct sk_buff *lp; 408671d93b39SHerbert Xu 40870ab03f35SSteffen Klassert if (unlikely(p->len + len >= 65536 || NAPI_GRO_CB(skb)->flush)) 408871d93b39SHerbert Xu return -E2BIG; 408971d93b39SHerbert Xu 409029e98242SEric Dumazet lp = NAPI_GRO_CB(p)->last; 40918a29111cSEric Dumazet pinfo = skb_shinfo(lp); 40928a29111cSEric Dumazet 40938a29111cSEric Dumazet if (headlen <= offset) { 409442da6994SHerbert Xu skb_frag_t *frag; 409566e92fcfSHerbert Xu skb_frag_t *frag2; 40969aaa156cSHerbert Xu int i = skbinfo->nr_frags; 40979aaa156cSHerbert Xu int nr_frags = pinfo->nr_frags + i; 409842da6994SHerbert Xu 409966e92fcfSHerbert Xu if (nr_frags > MAX_SKB_FRAGS) 41008a29111cSEric Dumazet goto merge; 410181705ad1SHerbert Xu 41028a29111cSEric Dumazet offset -= headlen; 41039aaa156cSHerbert Xu pinfo->nr_frags = nr_frags; 41049aaa156cSHerbert Xu skbinfo->nr_frags = 0; 4105f5572068SHerbert Xu 41069aaa156cSHerbert Xu frag = pinfo->frags + nr_frags; 41079aaa156cSHerbert Xu frag2 = skbinfo->frags + i; 410866e92fcfSHerbert Xu do { 410966e92fcfSHerbert Xu *--frag = *--frag2; 411066e92fcfSHerbert Xu } while (--i); 411166e92fcfSHerbert Xu 4112b54c9d5bSJonathan Lemon skb_frag_off_add(frag, offset); 41139e903e08SEric Dumazet skb_frag_size_sub(frag, offset); 411466e92fcfSHerbert Xu 4115715dc1f3SEric Dumazet /* all fragments truesize : remove (head size + sk_buff) */ 4116ec47ea82SAlexander Duyck delta_truesize = skb->truesize - 4117ec47ea82SAlexander Duyck SKB_TRUESIZE(skb_end_offset(skb)); 4118715dc1f3SEric Dumazet 4119f5572068SHerbert Xu skb->truesize -= skb->data_len; 4120f5572068SHerbert Xu skb->len -= skb->data_len; 4121f5572068SHerbert Xu skb->data_len = 0; 4122f5572068SHerbert Xu 4123715dc1f3SEric Dumazet NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE; 41245d38a079SHerbert Xu goto done; 4125d7e8883cSEric Dumazet } else if (skb->head_frag) { 4126d7e8883cSEric Dumazet int nr_frags = pinfo->nr_frags; 4127d7e8883cSEric Dumazet skb_frag_t *frag = pinfo->frags + nr_frags; 4128d7e8883cSEric Dumazet struct page *page = virt_to_head_page(skb->head); 4129d7e8883cSEric Dumazet unsigned int first_size = headlen - offset; 4130d7e8883cSEric Dumazet unsigned int first_offset; 4131d7e8883cSEric Dumazet 4132d7e8883cSEric Dumazet if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) 41338a29111cSEric Dumazet goto merge; 4134d7e8883cSEric Dumazet 4135d7e8883cSEric Dumazet first_offset = skb->data - 4136d7e8883cSEric Dumazet (unsigned char *)page_address(page) + 4137d7e8883cSEric Dumazet offset; 4138d7e8883cSEric Dumazet 4139d7e8883cSEric Dumazet pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags; 4140d7e8883cSEric Dumazet 4141d8e18a51SMatthew Wilcox (Oracle) __skb_frag_set_page(frag, page); 4142b54c9d5bSJonathan Lemon skb_frag_off_set(frag, first_offset); 4143d7e8883cSEric Dumazet skb_frag_size_set(frag, first_size); 4144d7e8883cSEric Dumazet 4145d7e8883cSEric Dumazet memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags); 4146d7e8883cSEric Dumazet /* We dont need to clear skbinfo->nr_frags here */ 4147d7e8883cSEric Dumazet 4148715dc1f3SEric Dumazet delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff)); 4149d7e8883cSEric Dumazet NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD; 4150d7e8883cSEric Dumazet goto done; 41518a29111cSEric Dumazet } 415271d93b39SHerbert Xu 415371d93b39SHerbert Xu merge: 4154715dc1f3SEric Dumazet delta_truesize = skb->truesize; 415567147ba9SHerbert Xu if (offset > headlen) { 4156d1dc7abfSMichal Schmidt unsigned int eat = offset - headlen; 4157d1dc7abfSMichal Schmidt 4158b54c9d5bSJonathan Lemon skb_frag_off_add(&skbinfo->frags[0], eat); 41599e903e08SEric Dumazet skb_frag_size_sub(&skbinfo->frags[0], eat); 4160d1dc7abfSMichal Schmidt skb->data_len -= eat; 4161d1dc7abfSMichal Schmidt skb->len -= eat; 416267147ba9SHerbert Xu offset = headlen; 416356035022SHerbert Xu } 416456035022SHerbert Xu 416567147ba9SHerbert Xu __skb_pull(skb, offset); 416656035022SHerbert Xu 416729e98242SEric Dumazet if (NAPI_GRO_CB(p)->last == p) 41688a29111cSEric Dumazet skb_shinfo(p)->frag_list = skb; 41698a29111cSEric Dumazet else 4170c3c7c254SEric Dumazet NAPI_GRO_CB(p)->last->next = skb; 4171c3c7c254SEric Dumazet NAPI_GRO_CB(p)->last = skb; 4172f4a775d1SEric Dumazet __skb_header_release(skb); 41738a29111cSEric Dumazet lp = p; 417471d93b39SHerbert Xu 41755d38a079SHerbert Xu done: 41765d38a079SHerbert Xu NAPI_GRO_CB(p)->count++; 417737fe4732SHerbert Xu p->data_len += len; 4178715dc1f3SEric Dumazet p->truesize += delta_truesize; 417937fe4732SHerbert Xu p->len += len; 41808a29111cSEric Dumazet if (lp != p) { 41818a29111cSEric Dumazet lp->data_len += len; 41828a29111cSEric Dumazet lp->truesize += delta_truesize; 41838a29111cSEric Dumazet lp->len += len; 41848a29111cSEric Dumazet } 418571d93b39SHerbert Xu NAPI_GRO_CB(skb)->same_flow = 1; 418671d93b39SHerbert Xu return 0; 418771d93b39SHerbert Xu } 418871d93b39SHerbert Xu 4189df5042f4SFlorian Westphal #ifdef CONFIG_SKB_EXTENSIONS 4190df5042f4SFlorian Westphal #define SKB_EXT_ALIGN_VALUE 8 4191df5042f4SFlorian Westphal #define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE) 4192df5042f4SFlorian Westphal 4193df5042f4SFlorian Westphal static const u8 skb_ext_type_len[] = { 4194df5042f4SFlorian Westphal #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 4195df5042f4SFlorian Westphal [SKB_EXT_BRIDGE_NF] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info), 4196df5042f4SFlorian Westphal #endif 41974165079bSFlorian Westphal #ifdef CONFIG_XFRM 41984165079bSFlorian Westphal [SKB_EXT_SEC_PATH] = SKB_EXT_CHUNKSIZEOF(struct sec_path), 41994165079bSFlorian Westphal #endif 420095a7233cSPaul Blakey #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 420195a7233cSPaul Blakey [TC_SKB_EXT] = SKB_EXT_CHUNKSIZEOF(struct tc_skb_ext), 420295a7233cSPaul Blakey #endif 42033ee17bc7SMat Martineau #if IS_ENABLED(CONFIG_MPTCP) 42043ee17bc7SMat Martineau [SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext), 42053ee17bc7SMat Martineau #endif 4206df5042f4SFlorian Westphal }; 4207df5042f4SFlorian Westphal 4208df5042f4SFlorian Westphal static __always_inline unsigned int skb_ext_total_length(void) 4209df5042f4SFlorian Westphal { 4210df5042f4SFlorian Westphal return SKB_EXT_CHUNKSIZEOF(struct skb_ext) + 4211df5042f4SFlorian Westphal #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 4212df5042f4SFlorian Westphal skb_ext_type_len[SKB_EXT_BRIDGE_NF] + 4213df5042f4SFlorian Westphal #endif 42144165079bSFlorian Westphal #ifdef CONFIG_XFRM 42154165079bSFlorian Westphal skb_ext_type_len[SKB_EXT_SEC_PATH] + 42164165079bSFlorian Westphal #endif 421795a7233cSPaul Blakey #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 421895a7233cSPaul Blakey skb_ext_type_len[TC_SKB_EXT] + 421995a7233cSPaul Blakey #endif 42203ee17bc7SMat Martineau #if IS_ENABLED(CONFIG_MPTCP) 42213ee17bc7SMat Martineau skb_ext_type_len[SKB_EXT_MPTCP] + 42223ee17bc7SMat Martineau #endif 4223df5042f4SFlorian Westphal 0; 4224df5042f4SFlorian Westphal } 4225df5042f4SFlorian Westphal 4226df5042f4SFlorian Westphal static void skb_extensions_init(void) 4227df5042f4SFlorian Westphal { 4228df5042f4SFlorian Westphal BUILD_BUG_ON(SKB_EXT_NUM >= 8); 4229df5042f4SFlorian Westphal BUILD_BUG_ON(skb_ext_total_length() > 255); 4230df5042f4SFlorian Westphal 4231df5042f4SFlorian Westphal skbuff_ext_cache = kmem_cache_create("skbuff_ext_cache", 4232df5042f4SFlorian Westphal SKB_EXT_ALIGN_VALUE * skb_ext_total_length(), 4233df5042f4SFlorian Westphal 0, 4234df5042f4SFlorian Westphal SLAB_HWCACHE_ALIGN|SLAB_PANIC, 4235df5042f4SFlorian Westphal NULL); 4236df5042f4SFlorian Westphal } 4237df5042f4SFlorian Westphal #else 4238df5042f4SFlorian Westphal static void skb_extensions_init(void) {} 4239df5042f4SFlorian Westphal #endif 4240df5042f4SFlorian Westphal 42411da177e4SLinus Torvalds void __init skb_init(void) 42421da177e4SLinus Torvalds { 424379a8a642SKees Cook skbuff_head_cache = kmem_cache_create_usercopy("skbuff_head_cache", 42441da177e4SLinus Torvalds sizeof(struct sk_buff), 42451da177e4SLinus Torvalds 0, 4246e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 424779a8a642SKees Cook offsetof(struct sk_buff, cb), 424879a8a642SKees Cook sizeof_field(struct sk_buff, cb), 424920c2df83SPaul Mundt NULL); 4250d179cd12SDavid S. Miller skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", 4251d0bf4a9eSEric Dumazet sizeof(struct sk_buff_fclones), 4252d179cd12SDavid S. Miller 0, 4253e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 425420c2df83SPaul Mundt NULL); 4255df5042f4SFlorian Westphal skb_extensions_init(); 42561da177e4SLinus Torvalds } 42571da177e4SLinus Torvalds 425851c739d1SDavid S. Miller static int 425948a1df65SJason A. Donenfeld __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len, 426048a1df65SJason A. Donenfeld unsigned int recursion_level) 4261716ea3a7SDavid Howells { 42621a028e50SDavid S. Miller int start = skb_headlen(skb); 42631a028e50SDavid S. Miller int i, copy = start - offset; 4264fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 4265716ea3a7SDavid Howells int elt = 0; 4266716ea3a7SDavid Howells 426748a1df65SJason A. Donenfeld if (unlikely(recursion_level >= 24)) 426848a1df65SJason A. Donenfeld return -EMSGSIZE; 426948a1df65SJason A. Donenfeld 4270716ea3a7SDavid Howells if (copy > 0) { 4271716ea3a7SDavid Howells if (copy > len) 4272716ea3a7SDavid Howells copy = len; 4273642f1490SJens Axboe sg_set_buf(sg, skb->data + offset, copy); 4274716ea3a7SDavid Howells elt++; 4275716ea3a7SDavid Howells if ((len -= copy) == 0) 4276716ea3a7SDavid Howells return elt; 4277716ea3a7SDavid Howells offset += copy; 4278716ea3a7SDavid Howells } 4279716ea3a7SDavid Howells 4280716ea3a7SDavid Howells for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 42811a028e50SDavid S. Miller int end; 4282716ea3a7SDavid Howells 4283547b792cSIlpo Järvinen WARN_ON(start > offset + len); 42841a028e50SDavid S. Miller 42859e903e08SEric Dumazet end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]); 4286716ea3a7SDavid Howells if ((copy = end - offset) > 0) { 4287716ea3a7SDavid Howells skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 428848a1df65SJason A. Donenfeld if (unlikely(elt && sg_is_last(&sg[elt - 1]))) 428948a1df65SJason A. Donenfeld return -EMSGSIZE; 4290716ea3a7SDavid Howells 4291716ea3a7SDavid Howells if (copy > len) 4292716ea3a7SDavid Howells copy = len; 4293ea2ab693SIan Campbell sg_set_page(&sg[elt], skb_frag_page(frag), copy, 4294b54c9d5bSJonathan Lemon skb_frag_off(frag) + offset - start); 4295716ea3a7SDavid Howells elt++; 4296716ea3a7SDavid Howells if (!(len -= copy)) 4297716ea3a7SDavid Howells return elt; 4298716ea3a7SDavid Howells offset += copy; 4299716ea3a7SDavid Howells } 43001a028e50SDavid S. Miller start = end; 4301716ea3a7SDavid Howells } 4302716ea3a7SDavid Howells 4303fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 430448a1df65SJason A. Donenfeld int end, ret; 4305716ea3a7SDavid Howells 4306547b792cSIlpo Järvinen WARN_ON(start > offset + len); 43071a028e50SDavid S. Miller 4308fbb398a8SDavid S. Miller end = start + frag_iter->len; 4309716ea3a7SDavid Howells if ((copy = end - offset) > 0) { 431048a1df65SJason A. Donenfeld if (unlikely(elt && sg_is_last(&sg[elt - 1]))) 431148a1df65SJason A. Donenfeld return -EMSGSIZE; 431248a1df65SJason A. Donenfeld 4313716ea3a7SDavid Howells if (copy > len) 4314716ea3a7SDavid Howells copy = len; 431548a1df65SJason A. Donenfeld ret = __skb_to_sgvec(frag_iter, sg+elt, offset - start, 431648a1df65SJason A. Donenfeld copy, recursion_level + 1); 431748a1df65SJason A. Donenfeld if (unlikely(ret < 0)) 431848a1df65SJason A. Donenfeld return ret; 431948a1df65SJason A. Donenfeld elt += ret; 4320716ea3a7SDavid Howells if ((len -= copy) == 0) 4321716ea3a7SDavid Howells return elt; 4322716ea3a7SDavid Howells offset += copy; 4323716ea3a7SDavid Howells } 43241a028e50SDavid S. Miller start = end; 4325716ea3a7SDavid Howells } 4326716ea3a7SDavid Howells BUG_ON(len); 4327716ea3a7SDavid Howells return elt; 4328716ea3a7SDavid Howells } 4329716ea3a7SDavid Howells 433048a1df65SJason A. Donenfeld /** 433148a1df65SJason A. Donenfeld * skb_to_sgvec - Fill a scatter-gather list from a socket buffer 433248a1df65SJason A. Donenfeld * @skb: Socket buffer containing the buffers to be mapped 433348a1df65SJason A. Donenfeld * @sg: The scatter-gather list to map into 433448a1df65SJason A. Donenfeld * @offset: The offset into the buffer's contents to start mapping 433548a1df65SJason A. Donenfeld * @len: Length of buffer space to be mapped 433648a1df65SJason A. Donenfeld * 433748a1df65SJason A. Donenfeld * Fill the specified scatter-gather list with mappings/pointers into a 433848a1df65SJason A. Donenfeld * region of the buffer space attached to a socket buffer. Returns either 433948a1df65SJason A. Donenfeld * the number of scatterlist items used, or -EMSGSIZE if the contents 434048a1df65SJason A. Donenfeld * could not fit. 434148a1df65SJason A. Donenfeld */ 434248a1df65SJason A. Donenfeld int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) 434348a1df65SJason A. Donenfeld { 434448a1df65SJason A. Donenfeld int nsg = __skb_to_sgvec(skb, sg, offset, len, 0); 434548a1df65SJason A. Donenfeld 434648a1df65SJason A. Donenfeld if (nsg <= 0) 434748a1df65SJason A. Donenfeld return nsg; 434848a1df65SJason A. Donenfeld 434948a1df65SJason A. Donenfeld sg_mark_end(&sg[nsg - 1]); 435048a1df65SJason A. Donenfeld 435148a1df65SJason A. Donenfeld return nsg; 435248a1df65SJason A. Donenfeld } 435348a1df65SJason A. Donenfeld EXPORT_SYMBOL_GPL(skb_to_sgvec); 435448a1df65SJason A. Donenfeld 435525a91d8dSFan Du /* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given 435625a91d8dSFan Du * sglist without mark the sg which contain last skb data as the end. 435725a91d8dSFan Du * So the caller can mannipulate sg list as will when padding new data after 435825a91d8dSFan Du * the first call without calling sg_unmark_end to expend sg list. 435925a91d8dSFan Du * 436025a91d8dSFan Du * Scenario to use skb_to_sgvec_nomark: 436125a91d8dSFan Du * 1. sg_init_table 436225a91d8dSFan Du * 2. skb_to_sgvec_nomark(payload1) 436325a91d8dSFan Du * 3. skb_to_sgvec_nomark(payload2) 436425a91d8dSFan Du * 436525a91d8dSFan Du * This is equivalent to: 436625a91d8dSFan Du * 1. sg_init_table 436725a91d8dSFan Du * 2. skb_to_sgvec(payload1) 436825a91d8dSFan Du * 3. sg_unmark_end 436925a91d8dSFan Du * 4. skb_to_sgvec(payload2) 437025a91d8dSFan Du * 437125a91d8dSFan Du * When mapping mutilple payload conditionally, skb_to_sgvec_nomark 437225a91d8dSFan Du * is more preferable. 437325a91d8dSFan Du */ 437425a91d8dSFan Du int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg, 437525a91d8dSFan Du int offset, int len) 437625a91d8dSFan Du { 437748a1df65SJason A. Donenfeld return __skb_to_sgvec(skb, sg, offset, len, 0); 437825a91d8dSFan Du } 437925a91d8dSFan Du EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark); 438025a91d8dSFan Du 438151c739d1SDavid S. Miller 438251c739d1SDavid S. Miller 4383716ea3a7SDavid Howells /** 4384716ea3a7SDavid Howells * skb_cow_data - Check that a socket buffer's data buffers are writable 4385716ea3a7SDavid Howells * @skb: The socket buffer to check. 4386716ea3a7SDavid Howells * @tailbits: Amount of trailing space to be added 4387716ea3a7SDavid Howells * @trailer: Returned pointer to the skb where the @tailbits space begins 4388716ea3a7SDavid Howells * 4389716ea3a7SDavid Howells * Make sure that the data buffers attached to a socket buffer are 4390716ea3a7SDavid Howells * writable. If they are not, private copies are made of the data buffers 4391716ea3a7SDavid Howells * and the socket buffer is set to use these instead. 4392716ea3a7SDavid Howells * 4393716ea3a7SDavid Howells * If @tailbits is given, make sure that there is space to write @tailbits 4394716ea3a7SDavid Howells * bytes of data beyond current end of socket buffer. @trailer will be 4395716ea3a7SDavid Howells * set to point to the skb in which this space begins. 4396716ea3a7SDavid Howells * 4397716ea3a7SDavid Howells * The number of scatterlist elements required to completely map the 4398716ea3a7SDavid Howells * COW'd and extended socket buffer will be returned. 4399716ea3a7SDavid Howells */ 4400716ea3a7SDavid Howells int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) 4401716ea3a7SDavid Howells { 4402716ea3a7SDavid Howells int copyflag; 4403716ea3a7SDavid Howells int elt; 4404716ea3a7SDavid Howells struct sk_buff *skb1, **skb_p; 4405716ea3a7SDavid Howells 4406716ea3a7SDavid Howells /* If skb is cloned or its head is paged, reallocate 4407716ea3a7SDavid Howells * head pulling out all the pages (pages are considered not writable 4408716ea3a7SDavid Howells * at the moment even if they are anonymous). 4409716ea3a7SDavid Howells */ 4410716ea3a7SDavid Howells if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) && 4411c15fc199SMiaohe Lin !__pskb_pull_tail(skb, __skb_pagelen(skb))) 4412716ea3a7SDavid Howells return -ENOMEM; 4413716ea3a7SDavid Howells 4414716ea3a7SDavid Howells /* Easy case. Most of packets will go this way. */ 441521dc3301SDavid S. Miller if (!skb_has_frag_list(skb)) { 4416716ea3a7SDavid Howells /* A little of trouble, not enough of space for trailer. 4417716ea3a7SDavid Howells * This should not happen, when stack is tuned to generate 4418716ea3a7SDavid Howells * good frames. OK, on miss we reallocate and reserve even more 4419716ea3a7SDavid Howells * space, 128 bytes is fair. */ 4420716ea3a7SDavid Howells 4421716ea3a7SDavid Howells if (skb_tailroom(skb) < tailbits && 4422716ea3a7SDavid Howells pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC)) 4423716ea3a7SDavid Howells return -ENOMEM; 4424716ea3a7SDavid Howells 4425716ea3a7SDavid Howells /* Voila! */ 4426716ea3a7SDavid Howells *trailer = skb; 4427716ea3a7SDavid Howells return 1; 4428716ea3a7SDavid Howells } 4429716ea3a7SDavid Howells 4430716ea3a7SDavid Howells /* Misery. We are in troubles, going to mincer fragments... */ 4431716ea3a7SDavid Howells 4432716ea3a7SDavid Howells elt = 1; 4433716ea3a7SDavid Howells skb_p = &skb_shinfo(skb)->frag_list; 4434716ea3a7SDavid Howells copyflag = 0; 4435716ea3a7SDavid Howells 4436716ea3a7SDavid Howells while ((skb1 = *skb_p) != NULL) { 4437716ea3a7SDavid Howells int ntail = 0; 4438716ea3a7SDavid Howells 4439716ea3a7SDavid Howells /* The fragment is partially pulled by someone, 4440716ea3a7SDavid Howells * this can happen on input. Copy it and everything 4441716ea3a7SDavid Howells * after it. */ 4442716ea3a7SDavid Howells 4443716ea3a7SDavid Howells if (skb_shared(skb1)) 4444716ea3a7SDavid Howells copyflag = 1; 4445716ea3a7SDavid Howells 4446716ea3a7SDavid Howells /* If the skb is the last, worry about trailer. */ 4447716ea3a7SDavid Howells 4448716ea3a7SDavid Howells if (skb1->next == NULL && tailbits) { 4449716ea3a7SDavid Howells if (skb_shinfo(skb1)->nr_frags || 445021dc3301SDavid S. Miller skb_has_frag_list(skb1) || 4451716ea3a7SDavid Howells skb_tailroom(skb1) < tailbits) 4452716ea3a7SDavid Howells ntail = tailbits + 128; 4453716ea3a7SDavid Howells } 4454716ea3a7SDavid Howells 4455716ea3a7SDavid Howells if (copyflag || 4456716ea3a7SDavid Howells skb_cloned(skb1) || 4457716ea3a7SDavid Howells ntail || 4458716ea3a7SDavid Howells skb_shinfo(skb1)->nr_frags || 445921dc3301SDavid S. Miller skb_has_frag_list(skb1)) { 4460716ea3a7SDavid Howells struct sk_buff *skb2; 4461716ea3a7SDavid Howells 4462716ea3a7SDavid Howells /* Fuck, we are miserable poor guys... */ 4463716ea3a7SDavid Howells if (ntail == 0) 4464716ea3a7SDavid Howells skb2 = skb_copy(skb1, GFP_ATOMIC); 4465716ea3a7SDavid Howells else 4466716ea3a7SDavid Howells skb2 = skb_copy_expand(skb1, 4467716ea3a7SDavid Howells skb_headroom(skb1), 4468716ea3a7SDavid Howells ntail, 4469716ea3a7SDavid Howells GFP_ATOMIC); 4470716ea3a7SDavid Howells if (unlikely(skb2 == NULL)) 4471716ea3a7SDavid Howells return -ENOMEM; 4472716ea3a7SDavid Howells 4473716ea3a7SDavid Howells if (skb1->sk) 4474716ea3a7SDavid Howells skb_set_owner_w(skb2, skb1->sk); 4475716ea3a7SDavid Howells 4476716ea3a7SDavid Howells /* Looking around. Are we still alive? 4477716ea3a7SDavid Howells * OK, link new skb, drop old one */ 4478716ea3a7SDavid Howells 4479716ea3a7SDavid Howells skb2->next = skb1->next; 4480716ea3a7SDavid Howells *skb_p = skb2; 4481716ea3a7SDavid Howells kfree_skb(skb1); 4482716ea3a7SDavid Howells skb1 = skb2; 4483716ea3a7SDavid Howells } 4484716ea3a7SDavid Howells elt++; 4485716ea3a7SDavid Howells *trailer = skb1; 4486716ea3a7SDavid Howells skb_p = &skb1->next; 4487716ea3a7SDavid Howells } 4488716ea3a7SDavid Howells 4489716ea3a7SDavid Howells return elt; 4490716ea3a7SDavid Howells } 4491b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_cow_data); 4492716ea3a7SDavid Howells 4493b1faf566SEric Dumazet static void sock_rmem_free(struct sk_buff *skb) 4494b1faf566SEric Dumazet { 4495b1faf566SEric Dumazet struct sock *sk = skb->sk; 4496b1faf566SEric Dumazet 4497b1faf566SEric Dumazet atomic_sub(skb->truesize, &sk->sk_rmem_alloc); 4498b1faf566SEric Dumazet } 4499b1faf566SEric Dumazet 45008605330aSSoheil Hassas Yeganeh static void skb_set_err_queue(struct sk_buff *skb) 45018605330aSSoheil Hassas Yeganeh { 45028605330aSSoheil Hassas Yeganeh /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING. 45038605330aSSoheil Hassas Yeganeh * So, it is safe to (mis)use it to mark skbs on the error queue. 45048605330aSSoheil Hassas Yeganeh */ 45058605330aSSoheil Hassas Yeganeh skb->pkt_type = PACKET_OUTGOING; 45068605330aSSoheil Hassas Yeganeh BUILD_BUG_ON(PACKET_OUTGOING == 0); 45078605330aSSoheil Hassas Yeganeh } 45088605330aSSoheil Hassas Yeganeh 4509b1faf566SEric Dumazet /* 4510b1faf566SEric Dumazet * Note: We dont mem charge error packets (no sk_forward_alloc changes) 4511b1faf566SEric Dumazet */ 4512b1faf566SEric Dumazet int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb) 4513b1faf566SEric Dumazet { 4514b1faf566SEric Dumazet if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 4515ebb3b78dSEric Dumazet (unsigned int)READ_ONCE(sk->sk_rcvbuf)) 4516b1faf566SEric Dumazet return -ENOMEM; 4517b1faf566SEric Dumazet 4518b1faf566SEric Dumazet skb_orphan(skb); 4519b1faf566SEric Dumazet skb->sk = sk; 4520b1faf566SEric Dumazet skb->destructor = sock_rmem_free; 4521b1faf566SEric Dumazet atomic_add(skb->truesize, &sk->sk_rmem_alloc); 45228605330aSSoheil Hassas Yeganeh skb_set_err_queue(skb); 4523b1faf566SEric Dumazet 4524abb57ea4SEric Dumazet /* before exiting rcu section, make sure dst is refcounted */ 4525abb57ea4SEric Dumazet skb_dst_force(skb); 4526abb57ea4SEric Dumazet 4527b1faf566SEric Dumazet skb_queue_tail(&sk->sk_error_queue, skb); 4528b1faf566SEric Dumazet if (!sock_flag(sk, SOCK_DEAD)) 45296e5d58fdSVinicius Costa Gomes sk->sk_error_report(sk); 4530b1faf566SEric Dumazet return 0; 4531b1faf566SEric Dumazet } 4532b1faf566SEric Dumazet EXPORT_SYMBOL(sock_queue_err_skb); 4533b1faf566SEric Dumazet 453483a1a1a7SSoheil Hassas Yeganeh static bool is_icmp_err_skb(const struct sk_buff *skb) 453583a1a1a7SSoheil Hassas Yeganeh { 453683a1a1a7SSoheil Hassas Yeganeh return skb && (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP || 453783a1a1a7SSoheil Hassas Yeganeh SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP6); 453883a1a1a7SSoheil Hassas Yeganeh } 453983a1a1a7SSoheil Hassas Yeganeh 4540364a9e93SWillem de Bruijn struct sk_buff *sock_dequeue_err_skb(struct sock *sk) 4541364a9e93SWillem de Bruijn { 4542364a9e93SWillem de Bruijn struct sk_buff_head *q = &sk->sk_error_queue; 454383a1a1a7SSoheil Hassas Yeganeh struct sk_buff *skb, *skb_next = NULL; 454483a1a1a7SSoheil Hassas Yeganeh bool icmp_next = false; 4545997d5c3fSEric Dumazet unsigned long flags; 4546364a9e93SWillem de Bruijn 4547997d5c3fSEric Dumazet spin_lock_irqsave(&q->lock, flags); 4548364a9e93SWillem de Bruijn skb = __skb_dequeue(q); 454938b25793SSoheil Hassas Yeganeh if (skb && (skb_next = skb_peek(q))) { 455083a1a1a7SSoheil Hassas Yeganeh icmp_next = is_icmp_err_skb(skb_next); 455138b25793SSoheil Hassas Yeganeh if (icmp_next) 4552985f7337SWillem de Bruijn sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_errno; 455338b25793SSoheil Hassas Yeganeh } 4554997d5c3fSEric Dumazet spin_unlock_irqrestore(&q->lock, flags); 4555364a9e93SWillem de Bruijn 455683a1a1a7SSoheil Hassas Yeganeh if (is_icmp_err_skb(skb) && !icmp_next) 455783a1a1a7SSoheil Hassas Yeganeh sk->sk_err = 0; 455883a1a1a7SSoheil Hassas Yeganeh 455983a1a1a7SSoheil Hassas Yeganeh if (skb_next) 4560364a9e93SWillem de Bruijn sk->sk_error_report(sk); 4561364a9e93SWillem de Bruijn 4562364a9e93SWillem de Bruijn return skb; 4563364a9e93SWillem de Bruijn } 4564364a9e93SWillem de Bruijn EXPORT_SYMBOL(sock_dequeue_err_skb); 4565364a9e93SWillem de Bruijn 4566cab41c47SAlexander Duyck /** 4567cab41c47SAlexander Duyck * skb_clone_sk - create clone of skb, and take reference to socket 4568cab41c47SAlexander Duyck * @skb: the skb to clone 4569cab41c47SAlexander Duyck * 4570cab41c47SAlexander Duyck * This function creates a clone of a buffer that holds a reference on 4571cab41c47SAlexander Duyck * sk_refcnt. Buffers created via this function are meant to be 4572cab41c47SAlexander Duyck * returned using sock_queue_err_skb, or free via kfree_skb. 4573cab41c47SAlexander Duyck * 4574cab41c47SAlexander Duyck * When passing buffers allocated with this function to sock_queue_err_skb 4575cab41c47SAlexander Duyck * it is necessary to wrap the call with sock_hold/sock_put in order to 4576cab41c47SAlexander Duyck * prevent the socket from being released prior to being enqueued on 4577cab41c47SAlexander Duyck * the sk_error_queue. 4578cab41c47SAlexander Duyck */ 457962bccb8cSAlexander Duyck struct sk_buff *skb_clone_sk(struct sk_buff *skb) 458062bccb8cSAlexander Duyck { 458162bccb8cSAlexander Duyck struct sock *sk = skb->sk; 458262bccb8cSAlexander Duyck struct sk_buff *clone; 458362bccb8cSAlexander Duyck 458441c6d650SReshetova, Elena if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt)) 458562bccb8cSAlexander Duyck return NULL; 458662bccb8cSAlexander Duyck 458762bccb8cSAlexander Duyck clone = skb_clone(skb, GFP_ATOMIC); 458862bccb8cSAlexander Duyck if (!clone) { 458962bccb8cSAlexander Duyck sock_put(sk); 459062bccb8cSAlexander Duyck return NULL; 459162bccb8cSAlexander Duyck } 459262bccb8cSAlexander Duyck 459362bccb8cSAlexander Duyck clone->sk = sk; 459462bccb8cSAlexander Duyck clone->destructor = sock_efree; 459562bccb8cSAlexander Duyck 459662bccb8cSAlexander Duyck return clone; 459762bccb8cSAlexander Duyck } 459862bccb8cSAlexander Duyck EXPORT_SYMBOL(skb_clone_sk); 459962bccb8cSAlexander Duyck 460037846ef0SAlexander Duyck static void __skb_complete_tx_timestamp(struct sk_buff *skb, 460137846ef0SAlexander Duyck struct sock *sk, 46024ef1b286SSoheil Hassas Yeganeh int tstype, 46034ef1b286SSoheil Hassas Yeganeh bool opt_stats) 4604ac45f602SPatrick Ohly { 4605ac45f602SPatrick Ohly struct sock_exterr_skb *serr; 4606ac45f602SPatrick Ohly int err; 4607ac45f602SPatrick Ohly 46084ef1b286SSoheil Hassas Yeganeh BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb)); 46094ef1b286SSoheil Hassas Yeganeh 4610ac45f602SPatrick Ohly serr = SKB_EXT_ERR(skb); 4611ac45f602SPatrick Ohly memset(serr, 0, sizeof(*serr)); 4612ac45f602SPatrick Ohly serr->ee.ee_errno = ENOMSG; 4613ac45f602SPatrick Ohly serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; 4614e7fd2885SWillem de Bruijn serr->ee.ee_info = tstype; 46154ef1b286SSoheil Hassas Yeganeh serr->opt_stats = opt_stats; 46161862d620SWillem de Bruijn serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0; 46174ed2d765SWillem de Bruijn if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) { 461809c2d251SWillem de Bruijn serr->ee.ee_data = skb_shinfo(skb)->tskey; 4619ac5cc977SWANG Cong if (sk->sk_protocol == IPPROTO_TCP && 4620ac5cc977SWANG Cong sk->sk_type == SOCK_STREAM) 46214ed2d765SWillem de Bruijn serr->ee.ee_data -= sk->sk_tskey; 46224ed2d765SWillem de Bruijn } 462329030374SEric Dumazet 4624ac45f602SPatrick Ohly err = sock_queue_err_skb(sk, skb); 462529030374SEric Dumazet 4626ac45f602SPatrick Ohly if (err) 4627ac45f602SPatrick Ohly kfree_skb(skb); 4628ac45f602SPatrick Ohly } 462937846ef0SAlexander Duyck 4630b245be1fSWillem de Bruijn static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly) 4631b245be1fSWillem de Bruijn { 4632b245be1fSWillem de Bruijn bool ret; 4633b245be1fSWillem de Bruijn 4634b245be1fSWillem de Bruijn if (likely(sysctl_tstamp_allow_data || tsonly)) 4635b245be1fSWillem de Bruijn return true; 4636b245be1fSWillem de Bruijn 4637b245be1fSWillem de Bruijn read_lock_bh(&sk->sk_callback_lock); 4638b245be1fSWillem de Bruijn ret = sk->sk_socket && sk->sk_socket->file && 4639b245be1fSWillem de Bruijn file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW); 4640b245be1fSWillem de Bruijn read_unlock_bh(&sk->sk_callback_lock); 4641b245be1fSWillem de Bruijn return ret; 4642b245be1fSWillem de Bruijn } 4643b245be1fSWillem de Bruijn 464437846ef0SAlexander Duyck void skb_complete_tx_timestamp(struct sk_buff *skb, 464537846ef0SAlexander Duyck struct skb_shared_hwtstamps *hwtstamps) 464637846ef0SAlexander Duyck { 464737846ef0SAlexander Duyck struct sock *sk = skb->sk; 464837846ef0SAlexander Duyck 4649b245be1fSWillem de Bruijn if (!skb_may_tx_timestamp(sk, false)) 465035b99dffSWillem de Bruijn goto err; 4651b245be1fSWillem de Bruijn 46529ac25fc0SEric Dumazet /* Take a reference to prevent skb_orphan() from freeing the socket, 46539ac25fc0SEric Dumazet * but only if the socket refcount is not zero. 46549ac25fc0SEric Dumazet */ 465541c6d650SReshetova, Elena if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) { 465637846ef0SAlexander Duyck *skb_hwtstamps(skb) = *hwtstamps; 46574ef1b286SSoheil Hassas Yeganeh __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false); 465837846ef0SAlexander Duyck sock_put(sk); 465935b99dffSWillem de Bruijn return; 466037846ef0SAlexander Duyck } 466135b99dffSWillem de Bruijn 466235b99dffSWillem de Bruijn err: 466335b99dffSWillem de Bruijn kfree_skb(skb); 46649ac25fc0SEric Dumazet } 466537846ef0SAlexander Duyck EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp); 466637846ef0SAlexander Duyck 466737846ef0SAlexander Duyck void __skb_tstamp_tx(struct sk_buff *orig_skb, 466837846ef0SAlexander Duyck struct skb_shared_hwtstamps *hwtstamps, 466937846ef0SAlexander Duyck struct sock *sk, int tstype) 467037846ef0SAlexander Duyck { 467137846ef0SAlexander Duyck struct sk_buff *skb; 46724ef1b286SSoheil Hassas Yeganeh bool tsonly, opt_stats = false; 467337846ef0SAlexander Duyck 46743a8dd971SWillem de Bruijn if (!sk) 46753a8dd971SWillem de Bruijn return; 46763a8dd971SWillem de Bruijn 4677b50a5c70SMiroslav Lichvar if (!hwtstamps && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) && 4678b50a5c70SMiroslav Lichvar skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS) 4679b50a5c70SMiroslav Lichvar return; 4680b50a5c70SMiroslav Lichvar 46813a8dd971SWillem de Bruijn tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY; 46823a8dd971SWillem de Bruijn if (!skb_may_tx_timestamp(sk, tsonly)) 468337846ef0SAlexander Duyck return; 468437846ef0SAlexander Duyck 46851c885808SFrancis Yan if (tsonly) { 46861c885808SFrancis Yan #ifdef CONFIG_INET 46871c885808SFrancis Yan if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) && 46881c885808SFrancis Yan sk->sk_protocol == IPPROTO_TCP && 46894ef1b286SSoheil Hassas Yeganeh sk->sk_type == SOCK_STREAM) { 469048040793SYousuk Seung skb = tcp_get_timestamping_opt_stats(sk, orig_skb); 46914ef1b286SSoheil Hassas Yeganeh opt_stats = true; 46924ef1b286SSoheil Hassas Yeganeh } else 46931c885808SFrancis Yan #endif 46941c885808SFrancis Yan skb = alloc_skb(0, GFP_ATOMIC); 46951c885808SFrancis Yan } else { 469637846ef0SAlexander Duyck skb = skb_clone(orig_skb, GFP_ATOMIC); 46971c885808SFrancis Yan } 469837846ef0SAlexander Duyck if (!skb) 469937846ef0SAlexander Duyck return; 470037846ef0SAlexander Duyck 470149ca0d8bSWillem de Bruijn if (tsonly) { 4702fff88030SWillem de Bruijn skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags & 4703fff88030SWillem de Bruijn SKBTX_ANY_TSTAMP; 470449ca0d8bSWillem de Bruijn skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey; 470549ca0d8bSWillem de Bruijn } 470649ca0d8bSWillem de Bruijn 470749ca0d8bSWillem de Bruijn if (hwtstamps) 470849ca0d8bSWillem de Bruijn *skb_hwtstamps(skb) = *hwtstamps; 470949ca0d8bSWillem de Bruijn else 471049ca0d8bSWillem de Bruijn skb->tstamp = ktime_get_real(); 471149ca0d8bSWillem de Bruijn 47124ef1b286SSoheil Hassas Yeganeh __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats); 471337846ef0SAlexander Duyck } 4714e7fd2885SWillem de Bruijn EXPORT_SYMBOL_GPL(__skb_tstamp_tx); 4715e7fd2885SWillem de Bruijn 4716e7fd2885SWillem de Bruijn void skb_tstamp_tx(struct sk_buff *orig_skb, 4717e7fd2885SWillem de Bruijn struct skb_shared_hwtstamps *hwtstamps) 4718e7fd2885SWillem de Bruijn { 4719e7fd2885SWillem de Bruijn return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk, 4720e7fd2885SWillem de Bruijn SCM_TSTAMP_SND); 4721e7fd2885SWillem de Bruijn } 4722ac45f602SPatrick Ohly EXPORT_SYMBOL_GPL(skb_tstamp_tx); 4723ac45f602SPatrick Ohly 47246e3e939fSJohannes Berg void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) 47256e3e939fSJohannes Berg { 47266e3e939fSJohannes Berg struct sock *sk = skb->sk; 47276e3e939fSJohannes Berg struct sock_exterr_skb *serr; 4728dd4f1072SEric Dumazet int err = 1; 47296e3e939fSJohannes Berg 47306e3e939fSJohannes Berg skb->wifi_acked_valid = 1; 47316e3e939fSJohannes Berg skb->wifi_acked = acked; 47326e3e939fSJohannes Berg 47336e3e939fSJohannes Berg serr = SKB_EXT_ERR(skb); 47346e3e939fSJohannes Berg memset(serr, 0, sizeof(*serr)); 47356e3e939fSJohannes Berg serr->ee.ee_errno = ENOMSG; 47366e3e939fSJohannes Berg serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS; 47376e3e939fSJohannes Berg 4738dd4f1072SEric Dumazet /* Take a reference to prevent skb_orphan() from freeing the socket, 4739dd4f1072SEric Dumazet * but only if the socket refcount is not zero. 4740dd4f1072SEric Dumazet */ 474141c6d650SReshetova, Elena if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) { 47426e3e939fSJohannes Berg err = sock_queue_err_skb(sk, skb); 4743dd4f1072SEric Dumazet sock_put(sk); 4744dd4f1072SEric Dumazet } 47456e3e939fSJohannes Berg if (err) 47466e3e939fSJohannes Berg kfree_skb(skb); 47476e3e939fSJohannes Berg } 47486e3e939fSJohannes Berg EXPORT_SYMBOL_GPL(skb_complete_wifi_ack); 47496e3e939fSJohannes Berg 4750f35d9d8aSRusty Russell /** 4751f35d9d8aSRusty Russell * skb_partial_csum_set - set up and verify partial csum values for packet 4752f35d9d8aSRusty Russell * @skb: the skb to set 4753f35d9d8aSRusty Russell * @start: the number of bytes after skb->data to start checksumming. 4754f35d9d8aSRusty Russell * @off: the offset from start to place the checksum. 4755f35d9d8aSRusty Russell * 4756f35d9d8aSRusty Russell * For untrusted partially-checksummed packets, we need to make sure the values 4757f35d9d8aSRusty Russell * for skb->csum_start and skb->csum_offset are valid so we don't oops. 4758f35d9d8aSRusty Russell * 4759f35d9d8aSRusty Russell * This function checks and sets those values and skb->ip_summed: if this 4760f35d9d8aSRusty Russell * returns false you should drop the packet. 4761f35d9d8aSRusty Russell */ 4762f35d9d8aSRusty Russell bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off) 4763f35d9d8aSRusty Russell { 476452b5d6f5SEric Dumazet u32 csum_end = (u32)start + (u32)off + sizeof(__sum16); 476552b5d6f5SEric Dumazet u32 csum_start = skb_headroom(skb) + (u32)start; 476652b5d6f5SEric Dumazet 476752b5d6f5SEric Dumazet if (unlikely(csum_start > U16_MAX || csum_end > skb_headlen(skb))) { 476852b5d6f5SEric Dumazet net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n", 476952b5d6f5SEric Dumazet start, off, skb_headroom(skb), skb_headlen(skb)); 4770f35d9d8aSRusty Russell return false; 4771f35d9d8aSRusty Russell } 4772f35d9d8aSRusty Russell skb->ip_summed = CHECKSUM_PARTIAL; 477352b5d6f5SEric Dumazet skb->csum_start = csum_start; 4774f35d9d8aSRusty Russell skb->csum_offset = off; 4775e5d5decaSJason Wang skb_set_transport_header(skb, start); 4776f35d9d8aSRusty Russell return true; 4777f35d9d8aSRusty Russell } 4778b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_partial_csum_set); 4779f35d9d8aSRusty Russell 4780ed1f50c3SPaul Durrant static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len, 4781ed1f50c3SPaul Durrant unsigned int max) 4782ed1f50c3SPaul Durrant { 4783ed1f50c3SPaul Durrant if (skb_headlen(skb) >= len) 4784ed1f50c3SPaul Durrant return 0; 4785ed1f50c3SPaul Durrant 4786ed1f50c3SPaul Durrant /* If we need to pullup then pullup to the max, so we 4787ed1f50c3SPaul Durrant * won't need to do it again. 4788ed1f50c3SPaul Durrant */ 4789ed1f50c3SPaul Durrant if (max > skb->len) 4790ed1f50c3SPaul Durrant max = skb->len; 4791ed1f50c3SPaul Durrant 4792ed1f50c3SPaul Durrant if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL) 4793ed1f50c3SPaul Durrant return -ENOMEM; 4794ed1f50c3SPaul Durrant 4795ed1f50c3SPaul Durrant if (skb_headlen(skb) < len) 4796ed1f50c3SPaul Durrant return -EPROTO; 4797ed1f50c3SPaul Durrant 4798ed1f50c3SPaul Durrant return 0; 4799ed1f50c3SPaul Durrant } 4800ed1f50c3SPaul Durrant 4801f9708b43SJan Beulich #define MAX_TCP_HDR_LEN (15 * 4) 4802f9708b43SJan Beulich 4803f9708b43SJan Beulich static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb, 4804f9708b43SJan Beulich typeof(IPPROTO_IP) proto, 4805f9708b43SJan Beulich unsigned int off) 4806f9708b43SJan Beulich { 4807f9708b43SJan Beulich int err; 4808f9708b43SJan Beulich 4809161d1792SKees Cook switch (proto) { 4810f9708b43SJan Beulich case IPPROTO_TCP: 4811f9708b43SJan Beulich err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr), 4812f9708b43SJan Beulich off + MAX_TCP_HDR_LEN); 4813f9708b43SJan Beulich if (!err && !skb_partial_csum_set(skb, off, 4814f9708b43SJan Beulich offsetof(struct tcphdr, 4815f9708b43SJan Beulich check))) 4816f9708b43SJan Beulich err = -EPROTO; 4817f9708b43SJan Beulich return err ? ERR_PTR(err) : &tcp_hdr(skb)->check; 4818f9708b43SJan Beulich 4819f9708b43SJan Beulich case IPPROTO_UDP: 4820f9708b43SJan Beulich err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr), 4821f9708b43SJan Beulich off + sizeof(struct udphdr)); 4822f9708b43SJan Beulich if (!err && !skb_partial_csum_set(skb, off, 4823f9708b43SJan Beulich offsetof(struct udphdr, 4824f9708b43SJan Beulich check))) 4825f9708b43SJan Beulich err = -EPROTO; 4826f9708b43SJan Beulich return err ? ERR_PTR(err) : &udp_hdr(skb)->check; 4827f9708b43SJan Beulich } 4828f9708b43SJan Beulich 4829f9708b43SJan Beulich return ERR_PTR(-EPROTO); 4830f9708b43SJan Beulich } 4831f9708b43SJan Beulich 4832ed1f50c3SPaul Durrant /* This value should be large enough to cover a tagged ethernet header plus 4833ed1f50c3SPaul Durrant * maximally sized IP and TCP or UDP headers. 4834ed1f50c3SPaul Durrant */ 4835ed1f50c3SPaul Durrant #define MAX_IP_HDR_LEN 128 4836ed1f50c3SPaul Durrant 4837f9708b43SJan Beulich static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate) 4838ed1f50c3SPaul Durrant { 4839ed1f50c3SPaul Durrant unsigned int off; 4840ed1f50c3SPaul Durrant bool fragment; 4841f9708b43SJan Beulich __sum16 *csum; 4842ed1f50c3SPaul Durrant int err; 4843ed1f50c3SPaul Durrant 4844ed1f50c3SPaul Durrant fragment = false; 4845ed1f50c3SPaul Durrant 4846ed1f50c3SPaul Durrant err = skb_maybe_pull_tail(skb, 4847ed1f50c3SPaul Durrant sizeof(struct iphdr), 4848ed1f50c3SPaul Durrant MAX_IP_HDR_LEN); 4849ed1f50c3SPaul Durrant if (err < 0) 4850ed1f50c3SPaul Durrant goto out; 4851ed1f50c3SPaul Durrant 485211f920d2SMiaohe Lin if (ip_is_fragment(ip_hdr(skb))) 4853ed1f50c3SPaul Durrant fragment = true; 4854ed1f50c3SPaul Durrant 4855ed1f50c3SPaul Durrant off = ip_hdrlen(skb); 4856ed1f50c3SPaul Durrant 4857ed1f50c3SPaul Durrant err = -EPROTO; 4858ed1f50c3SPaul Durrant 4859ed1f50c3SPaul Durrant if (fragment) 4860ed1f50c3SPaul Durrant goto out; 4861ed1f50c3SPaul Durrant 4862f9708b43SJan Beulich csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off); 4863f9708b43SJan Beulich if (IS_ERR(csum)) 4864f9708b43SJan Beulich return PTR_ERR(csum); 4865ed1f50c3SPaul Durrant 4866ed1f50c3SPaul Durrant if (recalculate) 4867f9708b43SJan Beulich *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr, 4868ed1f50c3SPaul Durrant ip_hdr(skb)->daddr, 4869ed1f50c3SPaul Durrant skb->len - off, 4870f9708b43SJan Beulich ip_hdr(skb)->protocol, 0); 4871ed1f50c3SPaul Durrant err = 0; 4872ed1f50c3SPaul Durrant 4873ed1f50c3SPaul Durrant out: 4874ed1f50c3SPaul Durrant return err; 4875ed1f50c3SPaul Durrant } 4876ed1f50c3SPaul Durrant 4877ed1f50c3SPaul Durrant /* This value should be large enough to cover a tagged ethernet header plus 4878ed1f50c3SPaul Durrant * an IPv6 header, all options, and a maximal TCP or UDP header. 4879ed1f50c3SPaul Durrant */ 4880ed1f50c3SPaul Durrant #define MAX_IPV6_HDR_LEN 256 4881ed1f50c3SPaul Durrant 4882ed1f50c3SPaul Durrant #define OPT_HDR(type, skb, off) \ 4883ed1f50c3SPaul Durrant (type *)(skb_network_header(skb) + (off)) 4884ed1f50c3SPaul Durrant 4885ed1f50c3SPaul Durrant static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate) 4886ed1f50c3SPaul Durrant { 4887ed1f50c3SPaul Durrant int err; 4888ed1f50c3SPaul Durrant u8 nexthdr; 4889ed1f50c3SPaul Durrant unsigned int off; 4890ed1f50c3SPaul Durrant unsigned int len; 4891ed1f50c3SPaul Durrant bool fragment; 4892ed1f50c3SPaul Durrant bool done; 4893f9708b43SJan Beulich __sum16 *csum; 4894ed1f50c3SPaul Durrant 4895ed1f50c3SPaul Durrant fragment = false; 4896ed1f50c3SPaul Durrant done = false; 4897ed1f50c3SPaul Durrant 4898ed1f50c3SPaul Durrant off = sizeof(struct ipv6hdr); 4899ed1f50c3SPaul Durrant 4900ed1f50c3SPaul Durrant err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN); 4901ed1f50c3SPaul Durrant if (err < 0) 4902ed1f50c3SPaul Durrant goto out; 4903ed1f50c3SPaul Durrant 4904ed1f50c3SPaul Durrant nexthdr = ipv6_hdr(skb)->nexthdr; 4905ed1f50c3SPaul Durrant 4906ed1f50c3SPaul Durrant len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len); 4907ed1f50c3SPaul Durrant while (off <= len && !done) { 4908ed1f50c3SPaul Durrant switch (nexthdr) { 4909ed1f50c3SPaul Durrant case IPPROTO_DSTOPTS: 4910ed1f50c3SPaul Durrant case IPPROTO_HOPOPTS: 4911ed1f50c3SPaul Durrant case IPPROTO_ROUTING: { 4912ed1f50c3SPaul Durrant struct ipv6_opt_hdr *hp; 4913ed1f50c3SPaul Durrant 4914ed1f50c3SPaul Durrant err = skb_maybe_pull_tail(skb, 4915ed1f50c3SPaul Durrant off + 4916ed1f50c3SPaul Durrant sizeof(struct ipv6_opt_hdr), 4917ed1f50c3SPaul Durrant MAX_IPV6_HDR_LEN); 4918ed1f50c3SPaul Durrant if (err < 0) 4919ed1f50c3SPaul Durrant goto out; 4920ed1f50c3SPaul Durrant 4921ed1f50c3SPaul Durrant hp = OPT_HDR(struct ipv6_opt_hdr, skb, off); 4922ed1f50c3SPaul Durrant nexthdr = hp->nexthdr; 4923ed1f50c3SPaul Durrant off += ipv6_optlen(hp); 4924ed1f50c3SPaul Durrant break; 4925ed1f50c3SPaul Durrant } 4926ed1f50c3SPaul Durrant case IPPROTO_AH: { 4927ed1f50c3SPaul Durrant struct ip_auth_hdr *hp; 4928ed1f50c3SPaul Durrant 4929ed1f50c3SPaul Durrant err = skb_maybe_pull_tail(skb, 4930ed1f50c3SPaul Durrant off + 4931ed1f50c3SPaul Durrant sizeof(struct ip_auth_hdr), 4932ed1f50c3SPaul Durrant MAX_IPV6_HDR_LEN); 4933ed1f50c3SPaul Durrant if (err < 0) 4934ed1f50c3SPaul Durrant goto out; 4935ed1f50c3SPaul Durrant 4936ed1f50c3SPaul Durrant hp = OPT_HDR(struct ip_auth_hdr, skb, off); 4937ed1f50c3SPaul Durrant nexthdr = hp->nexthdr; 4938ed1f50c3SPaul Durrant off += ipv6_authlen(hp); 4939ed1f50c3SPaul Durrant break; 4940ed1f50c3SPaul Durrant } 4941ed1f50c3SPaul Durrant case IPPROTO_FRAGMENT: { 4942ed1f50c3SPaul Durrant struct frag_hdr *hp; 4943ed1f50c3SPaul Durrant 4944ed1f50c3SPaul Durrant err = skb_maybe_pull_tail(skb, 4945ed1f50c3SPaul Durrant off + 4946ed1f50c3SPaul Durrant sizeof(struct frag_hdr), 4947ed1f50c3SPaul Durrant MAX_IPV6_HDR_LEN); 4948ed1f50c3SPaul Durrant if (err < 0) 4949ed1f50c3SPaul Durrant goto out; 4950ed1f50c3SPaul Durrant 4951ed1f50c3SPaul Durrant hp = OPT_HDR(struct frag_hdr, skb, off); 4952ed1f50c3SPaul Durrant 4953ed1f50c3SPaul Durrant if (hp->frag_off & htons(IP6_OFFSET | IP6_MF)) 4954ed1f50c3SPaul Durrant fragment = true; 4955ed1f50c3SPaul Durrant 4956ed1f50c3SPaul Durrant nexthdr = hp->nexthdr; 4957ed1f50c3SPaul Durrant off += sizeof(struct frag_hdr); 4958ed1f50c3SPaul Durrant break; 4959ed1f50c3SPaul Durrant } 4960ed1f50c3SPaul Durrant default: 4961ed1f50c3SPaul Durrant done = true; 4962ed1f50c3SPaul Durrant break; 4963ed1f50c3SPaul Durrant } 4964ed1f50c3SPaul Durrant } 4965ed1f50c3SPaul Durrant 4966ed1f50c3SPaul Durrant err = -EPROTO; 4967ed1f50c3SPaul Durrant 4968ed1f50c3SPaul Durrant if (!done || fragment) 4969ed1f50c3SPaul Durrant goto out; 4970ed1f50c3SPaul Durrant 4971f9708b43SJan Beulich csum = skb_checksum_setup_ip(skb, nexthdr, off); 4972f9708b43SJan Beulich if (IS_ERR(csum)) 4973f9708b43SJan Beulich return PTR_ERR(csum); 4974ed1f50c3SPaul Durrant 4975ed1f50c3SPaul Durrant if (recalculate) 4976f9708b43SJan Beulich *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr, 4977ed1f50c3SPaul Durrant &ipv6_hdr(skb)->daddr, 4978f9708b43SJan Beulich skb->len - off, nexthdr, 0); 4979ed1f50c3SPaul Durrant err = 0; 4980ed1f50c3SPaul Durrant 4981ed1f50c3SPaul Durrant out: 4982ed1f50c3SPaul Durrant return err; 4983ed1f50c3SPaul Durrant } 4984ed1f50c3SPaul Durrant 4985ed1f50c3SPaul Durrant /** 4986ed1f50c3SPaul Durrant * skb_checksum_setup - set up partial checksum offset 4987ed1f50c3SPaul Durrant * @skb: the skb to set up 4988ed1f50c3SPaul Durrant * @recalculate: if true the pseudo-header checksum will be recalculated 4989ed1f50c3SPaul Durrant */ 4990ed1f50c3SPaul Durrant int skb_checksum_setup(struct sk_buff *skb, bool recalculate) 4991ed1f50c3SPaul Durrant { 4992ed1f50c3SPaul Durrant int err; 4993ed1f50c3SPaul Durrant 4994ed1f50c3SPaul Durrant switch (skb->protocol) { 4995ed1f50c3SPaul Durrant case htons(ETH_P_IP): 4996f9708b43SJan Beulich err = skb_checksum_setup_ipv4(skb, recalculate); 4997ed1f50c3SPaul Durrant break; 4998ed1f50c3SPaul Durrant 4999ed1f50c3SPaul Durrant case htons(ETH_P_IPV6): 5000ed1f50c3SPaul Durrant err = skb_checksum_setup_ipv6(skb, recalculate); 5001ed1f50c3SPaul Durrant break; 5002ed1f50c3SPaul Durrant 5003ed1f50c3SPaul Durrant default: 5004ed1f50c3SPaul Durrant err = -EPROTO; 5005ed1f50c3SPaul Durrant break; 5006ed1f50c3SPaul Durrant } 5007ed1f50c3SPaul Durrant 5008ed1f50c3SPaul Durrant return err; 5009ed1f50c3SPaul Durrant } 5010ed1f50c3SPaul Durrant EXPORT_SYMBOL(skb_checksum_setup); 5011ed1f50c3SPaul Durrant 50129afd85c9SLinus Lüssing /** 50139afd85c9SLinus Lüssing * skb_checksum_maybe_trim - maybe trims the given skb 50149afd85c9SLinus Lüssing * @skb: the skb to check 50159afd85c9SLinus Lüssing * @transport_len: the data length beyond the network header 50169afd85c9SLinus Lüssing * 50179afd85c9SLinus Lüssing * Checks whether the given skb has data beyond the given transport length. 50189afd85c9SLinus Lüssing * If so, returns a cloned skb trimmed to this transport length. 50199afd85c9SLinus Lüssing * Otherwise returns the provided skb. Returns NULL in error cases 50209afd85c9SLinus Lüssing * (e.g. transport_len exceeds skb length or out-of-memory). 50219afd85c9SLinus Lüssing * 5022a516993fSLinus Lüssing * Caller needs to set the skb transport header and free any returned skb if it 5023a516993fSLinus Lüssing * differs from the provided skb. 50249afd85c9SLinus Lüssing */ 50259afd85c9SLinus Lüssing static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb, 50269afd85c9SLinus Lüssing unsigned int transport_len) 50279afd85c9SLinus Lüssing { 50289afd85c9SLinus Lüssing struct sk_buff *skb_chk; 50299afd85c9SLinus Lüssing unsigned int len = skb_transport_offset(skb) + transport_len; 50309afd85c9SLinus Lüssing int ret; 50319afd85c9SLinus Lüssing 5032a516993fSLinus Lüssing if (skb->len < len) 50339afd85c9SLinus Lüssing return NULL; 5034a516993fSLinus Lüssing else if (skb->len == len) 50359afd85c9SLinus Lüssing return skb; 50369afd85c9SLinus Lüssing 50379afd85c9SLinus Lüssing skb_chk = skb_clone(skb, GFP_ATOMIC); 50389afd85c9SLinus Lüssing if (!skb_chk) 50399afd85c9SLinus Lüssing return NULL; 50409afd85c9SLinus Lüssing 50419afd85c9SLinus Lüssing ret = pskb_trim_rcsum(skb_chk, len); 50429afd85c9SLinus Lüssing if (ret) { 50439afd85c9SLinus Lüssing kfree_skb(skb_chk); 50449afd85c9SLinus Lüssing return NULL; 50459afd85c9SLinus Lüssing } 50469afd85c9SLinus Lüssing 50479afd85c9SLinus Lüssing return skb_chk; 50489afd85c9SLinus Lüssing } 50499afd85c9SLinus Lüssing 50509afd85c9SLinus Lüssing /** 50519afd85c9SLinus Lüssing * skb_checksum_trimmed - validate checksum of an skb 50529afd85c9SLinus Lüssing * @skb: the skb to check 50539afd85c9SLinus Lüssing * @transport_len: the data length beyond the network header 50549afd85c9SLinus Lüssing * @skb_chkf: checksum function to use 50559afd85c9SLinus Lüssing * 50569afd85c9SLinus Lüssing * Applies the given checksum function skb_chkf to the provided skb. 50579afd85c9SLinus Lüssing * Returns a checked and maybe trimmed skb. Returns NULL on error. 50589afd85c9SLinus Lüssing * 50599afd85c9SLinus Lüssing * If the skb has data beyond the given transport length, then a 50609afd85c9SLinus Lüssing * trimmed & cloned skb is checked and returned. 50619afd85c9SLinus Lüssing * 5062a516993fSLinus Lüssing * Caller needs to set the skb transport header and free any returned skb if it 5063a516993fSLinus Lüssing * differs from the provided skb. 50649afd85c9SLinus Lüssing */ 50659afd85c9SLinus Lüssing struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb, 50669afd85c9SLinus Lüssing unsigned int transport_len, 50679afd85c9SLinus Lüssing __sum16(*skb_chkf)(struct sk_buff *skb)) 50689afd85c9SLinus Lüssing { 50699afd85c9SLinus Lüssing struct sk_buff *skb_chk; 50709afd85c9SLinus Lüssing unsigned int offset = skb_transport_offset(skb); 5071fcba67c9SLinus Lüssing __sum16 ret; 50729afd85c9SLinus Lüssing 50739afd85c9SLinus Lüssing skb_chk = skb_checksum_maybe_trim(skb, transport_len); 50749afd85c9SLinus Lüssing if (!skb_chk) 5075a516993fSLinus Lüssing goto err; 50769afd85c9SLinus Lüssing 5077a516993fSLinus Lüssing if (!pskb_may_pull(skb_chk, offset)) 5078a516993fSLinus Lüssing goto err; 50799afd85c9SLinus Lüssing 50809b368814SLinus Lüssing skb_pull_rcsum(skb_chk, offset); 50819afd85c9SLinus Lüssing ret = skb_chkf(skb_chk); 50829b368814SLinus Lüssing skb_push_rcsum(skb_chk, offset); 50839afd85c9SLinus Lüssing 5084a516993fSLinus Lüssing if (ret) 5085a516993fSLinus Lüssing goto err; 50869afd85c9SLinus Lüssing 50879afd85c9SLinus Lüssing return skb_chk; 5088a516993fSLinus Lüssing 5089a516993fSLinus Lüssing err: 5090a516993fSLinus Lüssing if (skb_chk && skb_chk != skb) 5091a516993fSLinus Lüssing kfree_skb(skb_chk); 5092a516993fSLinus Lüssing 5093a516993fSLinus Lüssing return NULL; 5094a516993fSLinus Lüssing 50959afd85c9SLinus Lüssing } 50969afd85c9SLinus Lüssing EXPORT_SYMBOL(skb_checksum_trimmed); 50979afd85c9SLinus Lüssing 50984497b076SBen Hutchings void __skb_warn_lro_forwarding(const struct sk_buff *skb) 50994497b076SBen Hutchings { 5100e87cc472SJoe Perches net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n", 5101e87cc472SJoe Perches skb->dev->name); 51024497b076SBen Hutchings } 51034497b076SBen Hutchings EXPORT_SYMBOL(__skb_warn_lro_forwarding); 5104bad43ca8SEric Dumazet 5105bad43ca8SEric Dumazet void kfree_skb_partial(struct sk_buff *skb, bool head_stolen) 5106bad43ca8SEric Dumazet { 51073d861f66SEric Dumazet if (head_stolen) { 51083d861f66SEric Dumazet skb_release_head_state(skb); 5109bad43ca8SEric Dumazet kmem_cache_free(skbuff_head_cache, skb); 51103d861f66SEric Dumazet } else { 5111bad43ca8SEric Dumazet __kfree_skb(skb); 5112bad43ca8SEric Dumazet } 51133d861f66SEric Dumazet } 5114bad43ca8SEric Dumazet EXPORT_SYMBOL(kfree_skb_partial); 5115bad43ca8SEric Dumazet 5116bad43ca8SEric Dumazet /** 5117bad43ca8SEric Dumazet * skb_try_coalesce - try to merge skb to prior one 5118bad43ca8SEric Dumazet * @to: prior buffer 5119bad43ca8SEric Dumazet * @from: buffer to add 5120bad43ca8SEric Dumazet * @fragstolen: pointer to boolean 5121c6c4b97cSRandy Dunlap * @delta_truesize: how much more was allocated than was requested 5122bad43ca8SEric Dumazet */ 5123bad43ca8SEric Dumazet bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, 5124bad43ca8SEric Dumazet bool *fragstolen, int *delta_truesize) 5125bad43ca8SEric Dumazet { 5126c818fa9eSEric Dumazet struct skb_shared_info *to_shinfo, *from_shinfo; 5127bad43ca8SEric Dumazet int i, delta, len = from->len; 5128bad43ca8SEric Dumazet 5129bad43ca8SEric Dumazet *fragstolen = false; 5130bad43ca8SEric Dumazet 5131bad43ca8SEric Dumazet if (skb_cloned(to)) 5132bad43ca8SEric Dumazet return false; 5133bad43ca8SEric Dumazet 5134bad43ca8SEric Dumazet if (len <= skb_tailroom(to)) { 5135e93a0435SEric Dumazet if (len) 5136bad43ca8SEric Dumazet BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len)); 5137bad43ca8SEric Dumazet *delta_truesize = 0; 5138bad43ca8SEric Dumazet return true; 5139bad43ca8SEric Dumazet } 5140bad43ca8SEric Dumazet 5141c818fa9eSEric Dumazet to_shinfo = skb_shinfo(to); 5142c818fa9eSEric Dumazet from_shinfo = skb_shinfo(from); 5143c818fa9eSEric Dumazet if (to_shinfo->frag_list || from_shinfo->frag_list) 5144bad43ca8SEric Dumazet return false; 51451f8b977aSWillem de Bruijn if (skb_zcopy(to) || skb_zcopy(from)) 51461f8b977aSWillem de Bruijn return false; 5147bad43ca8SEric Dumazet 5148bad43ca8SEric Dumazet if (skb_headlen(from) != 0) { 5149bad43ca8SEric Dumazet struct page *page; 5150bad43ca8SEric Dumazet unsigned int offset; 5151bad43ca8SEric Dumazet 5152c818fa9eSEric Dumazet if (to_shinfo->nr_frags + 5153c818fa9eSEric Dumazet from_shinfo->nr_frags >= MAX_SKB_FRAGS) 5154bad43ca8SEric Dumazet return false; 5155bad43ca8SEric Dumazet 5156bad43ca8SEric Dumazet if (skb_head_is_locked(from)) 5157bad43ca8SEric Dumazet return false; 5158bad43ca8SEric Dumazet 5159bad43ca8SEric Dumazet delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff)); 5160bad43ca8SEric Dumazet 5161bad43ca8SEric Dumazet page = virt_to_head_page(from->head); 5162bad43ca8SEric Dumazet offset = from->data - (unsigned char *)page_address(page); 5163bad43ca8SEric Dumazet 5164c818fa9eSEric Dumazet skb_fill_page_desc(to, to_shinfo->nr_frags, 5165bad43ca8SEric Dumazet page, offset, skb_headlen(from)); 5166bad43ca8SEric Dumazet *fragstolen = true; 5167bad43ca8SEric Dumazet } else { 5168c818fa9eSEric Dumazet if (to_shinfo->nr_frags + 5169c818fa9eSEric Dumazet from_shinfo->nr_frags > MAX_SKB_FRAGS) 5170bad43ca8SEric Dumazet return false; 5171bad43ca8SEric Dumazet 5172f4b549a5SWeiping Pan delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from)); 5173bad43ca8SEric Dumazet } 5174bad43ca8SEric Dumazet 5175bad43ca8SEric Dumazet WARN_ON_ONCE(delta < len); 5176bad43ca8SEric Dumazet 5177c818fa9eSEric Dumazet memcpy(to_shinfo->frags + to_shinfo->nr_frags, 5178c818fa9eSEric Dumazet from_shinfo->frags, 5179c818fa9eSEric Dumazet from_shinfo->nr_frags * sizeof(skb_frag_t)); 5180c818fa9eSEric Dumazet to_shinfo->nr_frags += from_shinfo->nr_frags; 5181bad43ca8SEric Dumazet 5182bad43ca8SEric Dumazet if (!skb_cloned(from)) 5183c818fa9eSEric Dumazet from_shinfo->nr_frags = 0; 5184bad43ca8SEric Dumazet 51858ea853fdSLi RongQing /* if the skb is not cloned this does nothing 51868ea853fdSLi RongQing * since we set nr_frags to 0. 51878ea853fdSLi RongQing */ 5188c818fa9eSEric Dumazet for (i = 0; i < from_shinfo->nr_frags; i++) 5189c818fa9eSEric Dumazet __skb_frag_ref(&from_shinfo->frags[i]); 5190bad43ca8SEric Dumazet 5191bad43ca8SEric Dumazet to->truesize += delta; 5192bad43ca8SEric Dumazet to->len += len; 5193bad43ca8SEric Dumazet to->data_len += len; 5194bad43ca8SEric Dumazet 5195bad43ca8SEric Dumazet *delta_truesize = delta; 5196bad43ca8SEric Dumazet return true; 5197bad43ca8SEric Dumazet } 5198bad43ca8SEric Dumazet EXPORT_SYMBOL(skb_try_coalesce); 5199621e84d6SNicolas Dichtel 5200621e84d6SNicolas Dichtel /** 52018b27f277SNicolas Dichtel * skb_scrub_packet - scrub an skb 5202621e84d6SNicolas Dichtel * 5203621e84d6SNicolas Dichtel * @skb: buffer to clean 52048b27f277SNicolas Dichtel * @xnet: packet is crossing netns 5205621e84d6SNicolas Dichtel * 52068b27f277SNicolas Dichtel * skb_scrub_packet can be used after encapsulating or decapsulting a packet 52078b27f277SNicolas Dichtel * into/from a tunnel. Some information have to be cleared during these 52088b27f277SNicolas Dichtel * operations. 52098b27f277SNicolas Dichtel * skb_scrub_packet can also be used to clean a skb before injecting it in 52108b27f277SNicolas Dichtel * another namespace (@xnet == true). We have to clear all information in the 52118b27f277SNicolas Dichtel * skb that could impact namespace isolation. 5212621e84d6SNicolas Dichtel */ 52138b27f277SNicolas Dichtel void skb_scrub_packet(struct sk_buff *skb, bool xnet) 5214621e84d6SNicolas Dichtel { 5215621e84d6SNicolas Dichtel skb->pkt_type = PACKET_HOST; 5216621e84d6SNicolas Dichtel skb->skb_iif = 0; 521760ff7467SWANG Cong skb->ignore_df = 0; 5218621e84d6SNicolas Dichtel skb_dst_drop(skb); 5219174e2381SFlorian Westphal skb_ext_reset(skb); 5220895b5c9fSFlorian Westphal nf_reset_ct(skb); 5221621e84d6SNicolas Dichtel nf_reset_trace(skb); 5222213dd74aSHerbert Xu 52236f9a5069SPetr Machata #ifdef CONFIG_NET_SWITCHDEV 52246f9a5069SPetr Machata skb->offload_fwd_mark = 0; 5225875e8939SIdo Schimmel skb->offload_l3_fwd_mark = 0; 52266f9a5069SPetr Machata #endif 52276f9a5069SPetr Machata 5228213dd74aSHerbert Xu if (!xnet) 5229213dd74aSHerbert Xu return; 5230213dd74aSHerbert Xu 52312b5ec1a5SYe Yin ipvs_reset(skb); 5232213dd74aSHerbert Xu skb->mark = 0; 5233c47d8c2fSJesus Sanchez-Palencia skb->tstamp = 0; 5234621e84d6SNicolas Dichtel } 5235621e84d6SNicolas Dichtel EXPORT_SYMBOL_GPL(skb_scrub_packet); 5236de960aa9SFlorian Westphal 5237de960aa9SFlorian Westphal /** 5238de960aa9SFlorian Westphal * skb_gso_transport_seglen - Return length of individual segments of a gso packet 5239de960aa9SFlorian Westphal * 5240de960aa9SFlorian Westphal * @skb: GSO skb 5241de960aa9SFlorian Westphal * 5242de960aa9SFlorian Westphal * skb_gso_transport_seglen is used to determine the real size of the 5243de960aa9SFlorian Westphal * individual segments, including Layer4 headers (TCP/UDP). 5244de960aa9SFlorian Westphal * 5245de960aa9SFlorian Westphal * The MAC/L2 or network (IP, IPv6) headers are not accounted for. 5246de960aa9SFlorian Westphal */ 5247a4a77718SDaniel Axtens static unsigned int skb_gso_transport_seglen(const struct sk_buff *skb) 5248de960aa9SFlorian Westphal { 5249de960aa9SFlorian Westphal const struct skb_shared_info *shinfo = skb_shinfo(skb); 5250f993bc25SFlorian Westphal unsigned int thlen = 0; 5251f993bc25SFlorian Westphal 5252f993bc25SFlorian Westphal if (skb->encapsulation) { 5253f993bc25SFlorian Westphal thlen = skb_inner_transport_header(skb) - 5254f993bc25SFlorian Westphal skb_transport_header(skb); 5255de960aa9SFlorian Westphal 5256de960aa9SFlorian Westphal if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) 5257f993bc25SFlorian Westphal thlen += inner_tcp_hdrlen(skb); 5258f993bc25SFlorian Westphal } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) { 5259f993bc25SFlorian Westphal thlen = tcp_hdrlen(skb); 52601dd27cdeSDaniel Axtens } else if (unlikely(skb_is_gso_sctp(skb))) { 526190017accSMarcelo Ricardo Leitner thlen = sizeof(struct sctphdr); 5262ee80d1ebSWillem de Bruijn } else if (shinfo->gso_type & SKB_GSO_UDP_L4) { 5263ee80d1ebSWillem de Bruijn thlen = sizeof(struct udphdr); 5264f993bc25SFlorian Westphal } 52656d39d589SFlorian Westphal /* UFO sets gso_size to the size of the fragmentation 52666d39d589SFlorian Westphal * payload, i.e. the size of the L4 (UDP) header is already 52676d39d589SFlorian Westphal * accounted for. 52686d39d589SFlorian Westphal */ 5269f993bc25SFlorian Westphal return thlen + shinfo->gso_size; 5270de960aa9SFlorian Westphal } 5271a4a77718SDaniel Axtens 5272a4a77718SDaniel Axtens /** 5273a4a77718SDaniel Axtens * skb_gso_network_seglen - Return length of individual segments of a gso packet 5274a4a77718SDaniel Axtens * 5275a4a77718SDaniel Axtens * @skb: GSO skb 5276a4a77718SDaniel Axtens * 5277a4a77718SDaniel Axtens * skb_gso_network_seglen is used to determine the real size of the 5278a4a77718SDaniel Axtens * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP). 5279a4a77718SDaniel Axtens * 5280a4a77718SDaniel Axtens * The MAC/L2 header is not accounted for. 5281a4a77718SDaniel Axtens */ 5282a4a77718SDaniel Axtens static unsigned int skb_gso_network_seglen(const struct sk_buff *skb) 5283a4a77718SDaniel Axtens { 5284a4a77718SDaniel Axtens unsigned int hdr_len = skb_transport_header(skb) - 5285a4a77718SDaniel Axtens skb_network_header(skb); 5286a4a77718SDaniel Axtens 5287a4a77718SDaniel Axtens return hdr_len + skb_gso_transport_seglen(skb); 5288a4a77718SDaniel Axtens } 5289a4a77718SDaniel Axtens 5290a4a77718SDaniel Axtens /** 5291a4a77718SDaniel Axtens * skb_gso_mac_seglen - Return length of individual segments of a gso packet 5292a4a77718SDaniel Axtens * 5293a4a77718SDaniel Axtens * @skb: GSO skb 5294a4a77718SDaniel Axtens * 5295a4a77718SDaniel Axtens * skb_gso_mac_seglen is used to determine the real size of the 5296a4a77718SDaniel Axtens * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4 5297a4a77718SDaniel Axtens * headers (TCP/UDP). 5298a4a77718SDaniel Axtens */ 5299a4a77718SDaniel Axtens static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb) 5300a4a77718SDaniel Axtens { 5301a4a77718SDaniel Axtens unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb); 5302a4a77718SDaniel Axtens 5303a4a77718SDaniel Axtens return hdr_len + skb_gso_transport_seglen(skb); 5304a4a77718SDaniel Axtens } 53050d5501c1SVlad Yasevich 5306ae7ef81eSMarcelo Ricardo Leitner /** 53072b16f048SDaniel Axtens * skb_gso_size_check - check the skb size, considering GSO_BY_FRAGS 53082b16f048SDaniel Axtens * 53092b16f048SDaniel Axtens * There are a couple of instances where we have a GSO skb, and we 53102b16f048SDaniel Axtens * want to determine what size it would be after it is segmented. 53112b16f048SDaniel Axtens * 53122b16f048SDaniel Axtens * We might want to check: 53132b16f048SDaniel Axtens * - L3+L4+payload size (e.g. IP forwarding) 53142b16f048SDaniel Axtens * - L2+L3+L4+payload size (e.g. sanity check before passing to driver) 53152b16f048SDaniel Axtens * 53162b16f048SDaniel Axtens * This is a helper to do that correctly considering GSO_BY_FRAGS. 53172b16f048SDaniel Axtens * 531849682bfaSMathieu Malaterre * @skb: GSO skb 531949682bfaSMathieu Malaterre * 53202b16f048SDaniel Axtens * @seg_len: The segmented length (from skb_gso_*_seglen). In the 53212b16f048SDaniel Axtens * GSO_BY_FRAGS case this will be [header sizes + GSO_BY_FRAGS]. 53222b16f048SDaniel Axtens * 53232b16f048SDaniel Axtens * @max_len: The maximum permissible length. 53242b16f048SDaniel Axtens * 53252b16f048SDaniel Axtens * Returns true if the segmented length <= max length. 53262b16f048SDaniel Axtens */ 53272b16f048SDaniel Axtens static inline bool skb_gso_size_check(const struct sk_buff *skb, 53282b16f048SDaniel Axtens unsigned int seg_len, 53292b16f048SDaniel Axtens unsigned int max_len) { 53302b16f048SDaniel Axtens const struct skb_shared_info *shinfo = skb_shinfo(skb); 53312b16f048SDaniel Axtens const struct sk_buff *iter; 53322b16f048SDaniel Axtens 53332b16f048SDaniel Axtens if (shinfo->gso_size != GSO_BY_FRAGS) 53342b16f048SDaniel Axtens return seg_len <= max_len; 53352b16f048SDaniel Axtens 53362b16f048SDaniel Axtens /* Undo this so we can re-use header sizes */ 53372b16f048SDaniel Axtens seg_len -= GSO_BY_FRAGS; 53382b16f048SDaniel Axtens 53392b16f048SDaniel Axtens skb_walk_frags(skb, iter) { 53402b16f048SDaniel Axtens if (seg_len + skb_headlen(iter) > max_len) 53412b16f048SDaniel Axtens return false; 53422b16f048SDaniel Axtens } 53432b16f048SDaniel Axtens 53442b16f048SDaniel Axtens return true; 53452b16f048SDaniel Axtens } 53462b16f048SDaniel Axtens 53472b16f048SDaniel Axtens /** 5348779b7931SDaniel Axtens * skb_gso_validate_network_len - Will a split GSO skb fit into a given MTU? 5349ae7ef81eSMarcelo Ricardo Leitner * 5350ae7ef81eSMarcelo Ricardo Leitner * @skb: GSO skb 535176f21b99SDavid S. Miller * @mtu: MTU to validate against 5352ae7ef81eSMarcelo Ricardo Leitner * 5353779b7931SDaniel Axtens * skb_gso_validate_network_len validates if a given skb will fit a 5354779b7931SDaniel Axtens * wanted MTU once split. It considers L3 headers, L4 headers, and the 5355779b7931SDaniel Axtens * payload. 5356ae7ef81eSMarcelo Ricardo Leitner */ 5357779b7931SDaniel Axtens bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu) 5358ae7ef81eSMarcelo Ricardo Leitner { 53592b16f048SDaniel Axtens return skb_gso_size_check(skb, skb_gso_network_seglen(skb), mtu); 5360ae7ef81eSMarcelo Ricardo Leitner } 5361779b7931SDaniel Axtens EXPORT_SYMBOL_GPL(skb_gso_validate_network_len); 5362ae7ef81eSMarcelo Ricardo Leitner 53632b16f048SDaniel Axtens /** 53642b16f048SDaniel Axtens * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length? 53652b16f048SDaniel Axtens * 53662b16f048SDaniel Axtens * @skb: GSO skb 53672b16f048SDaniel Axtens * @len: length to validate against 53682b16f048SDaniel Axtens * 53692b16f048SDaniel Axtens * skb_gso_validate_mac_len validates if a given skb will fit a wanted 53702b16f048SDaniel Axtens * length once split, including L2, L3 and L4 headers and the payload. 53712b16f048SDaniel Axtens */ 53722b16f048SDaniel Axtens bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len) 53732b16f048SDaniel Axtens { 53742b16f048SDaniel Axtens return skb_gso_size_check(skb, skb_gso_mac_seglen(skb), len); 53752b16f048SDaniel Axtens } 53762b16f048SDaniel Axtens EXPORT_SYMBOL_GPL(skb_gso_validate_mac_len); 53772b16f048SDaniel Axtens 53780d5501c1SVlad Yasevich static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb) 53790d5501c1SVlad Yasevich { 5380d85e8be2SYuya Kusakabe int mac_len, meta_len; 5381d85e8be2SYuya Kusakabe void *meta; 53824bbb3e0eSToshiaki Makita 53830d5501c1SVlad Yasevich if (skb_cow(skb, skb_headroom(skb)) < 0) { 53840d5501c1SVlad Yasevich kfree_skb(skb); 53850d5501c1SVlad Yasevich return NULL; 53860d5501c1SVlad Yasevich } 53870d5501c1SVlad Yasevich 53884bbb3e0eSToshiaki Makita mac_len = skb->data - skb_mac_header(skb); 5389ae474573SToshiaki Makita if (likely(mac_len > VLAN_HLEN + ETH_TLEN)) { 53904bbb3e0eSToshiaki Makita memmove(skb_mac_header(skb) + VLAN_HLEN, skb_mac_header(skb), 53914bbb3e0eSToshiaki Makita mac_len - VLAN_HLEN - ETH_TLEN); 5392ae474573SToshiaki Makita } 5393d85e8be2SYuya Kusakabe 5394d85e8be2SYuya Kusakabe meta_len = skb_metadata_len(skb); 5395d85e8be2SYuya Kusakabe if (meta_len) { 5396d85e8be2SYuya Kusakabe meta = skb_metadata_end(skb) - meta_len; 5397d85e8be2SYuya Kusakabe memmove(meta + VLAN_HLEN, meta, meta_len); 5398d85e8be2SYuya Kusakabe } 5399d85e8be2SYuya Kusakabe 54000d5501c1SVlad Yasevich skb->mac_header += VLAN_HLEN; 54010d5501c1SVlad Yasevich return skb; 54020d5501c1SVlad Yasevich } 54030d5501c1SVlad Yasevich 54040d5501c1SVlad Yasevich struct sk_buff *skb_vlan_untag(struct sk_buff *skb) 54050d5501c1SVlad Yasevich { 54060d5501c1SVlad Yasevich struct vlan_hdr *vhdr; 54070d5501c1SVlad Yasevich u16 vlan_tci; 54080d5501c1SVlad Yasevich 5409df8a39deSJiri Pirko if (unlikely(skb_vlan_tag_present(skb))) { 54100d5501c1SVlad Yasevich /* vlan_tci is already set-up so leave this for another time */ 54110d5501c1SVlad Yasevich return skb; 54120d5501c1SVlad Yasevich } 54130d5501c1SVlad Yasevich 54140d5501c1SVlad Yasevich skb = skb_share_check(skb, GFP_ATOMIC); 54150d5501c1SVlad Yasevich if (unlikely(!skb)) 54160d5501c1SVlad Yasevich goto err_free; 541755eff0ebSMiaohe Lin /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */ 541855eff0ebSMiaohe Lin if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short)))) 54190d5501c1SVlad Yasevich goto err_free; 54200d5501c1SVlad Yasevich 54210d5501c1SVlad Yasevich vhdr = (struct vlan_hdr *)skb->data; 54220d5501c1SVlad Yasevich vlan_tci = ntohs(vhdr->h_vlan_TCI); 54230d5501c1SVlad Yasevich __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci); 54240d5501c1SVlad Yasevich 54250d5501c1SVlad Yasevich skb_pull_rcsum(skb, VLAN_HLEN); 54260d5501c1SVlad Yasevich vlan_set_encap_proto(skb, vhdr); 54270d5501c1SVlad Yasevich 54280d5501c1SVlad Yasevich skb = skb_reorder_vlan_header(skb); 54290d5501c1SVlad Yasevich if (unlikely(!skb)) 54300d5501c1SVlad Yasevich goto err_free; 54310d5501c1SVlad Yasevich 54320d5501c1SVlad Yasevich skb_reset_network_header(skb); 54330d5501c1SVlad Yasevich skb_reset_transport_header(skb); 54340d5501c1SVlad Yasevich skb_reset_mac_len(skb); 54350d5501c1SVlad Yasevich 54360d5501c1SVlad Yasevich return skb; 54370d5501c1SVlad Yasevich 54380d5501c1SVlad Yasevich err_free: 54390d5501c1SVlad Yasevich kfree_skb(skb); 54400d5501c1SVlad Yasevich return NULL; 54410d5501c1SVlad Yasevich } 54420d5501c1SVlad Yasevich EXPORT_SYMBOL(skb_vlan_untag); 54432e4e4410SEric Dumazet 5444e2195121SJiri Pirko int skb_ensure_writable(struct sk_buff *skb, int write_len) 5445e2195121SJiri Pirko { 5446e2195121SJiri Pirko if (!pskb_may_pull(skb, write_len)) 5447e2195121SJiri Pirko return -ENOMEM; 5448e2195121SJiri Pirko 5449e2195121SJiri Pirko if (!skb_cloned(skb) || skb_clone_writable(skb, write_len)) 5450e2195121SJiri Pirko return 0; 5451e2195121SJiri Pirko 5452e2195121SJiri Pirko return pskb_expand_head(skb, 0, 0, GFP_ATOMIC); 5453e2195121SJiri Pirko } 5454e2195121SJiri Pirko EXPORT_SYMBOL(skb_ensure_writable); 5455e2195121SJiri Pirko 5456bfca4c52SShmulik Ladkani /* remove VLAN header from packet and update csum accordingly. 5457bfca4c52SShmulik Ladkani * expects a non skb_vlan_tag_present skb with a vlan tag payload 5458bfca4c52SShmulik Ladkani */ 5459bfca4c52SShmulik Ladkani int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci) 546093515d53SJiri Pirko { 546193515d53SJiri Pirko struct vlan_hdr *vhdr; 5462b6a79208SShmulik Ladkani int offset = skb->data - skb_mac_header(skb); 546393515d53SJiri Pirko int err; 546493515d53SJiri Pirko 5465b6a79208SShmulik Ladkani if (WARN_ONCE(offset, 5466b6a79208SShmulik Ladkani "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n", 5467b6a79208SShmulik Ladkani offset)) { 5468b6a79208SShmulik Ladkani return -EINVAL; 5469b6a79208SShmulik Ladkani } 5470b6a79208SShmulik Ladkani 547193515d53SJiri Pirko err = skb_ensure_writable(skb, VLAN_ETH_HLEN); 547293515d53SJiri Pirko if (unlikely(err)) 5473b6a79208SShmulik Ladkani return err; 547493515d53SJiri Pirko 547593515d53SJiri Pirko skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN); 547693515d53SJiri Pirko 547793515d53SJiri Pirko vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN); 547893515d53SJiri Pirko *vlan_tci = ntohs(vhdr->h_vlan_TCI); 547993515d53SJiri Pirko 548093515d53SJiri Pirko memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN); 548193515d53SJiri Pirko __skb_pull(skb, VLAN_HLEN); 548293515d53SJiri Pirko 548393515d53SJiri Pirko vlan_set_encap_proto(skb, vhdr); 548493515d53SJiri Pirko skb->mac_header += VLAN_HLEN; 548593515d53SJiri Pirko 548693515d53SJiri Pirko if (skb_network_offset(skb) < ETH_HLEN) 548793515d53SJiri Pirko skb_set_network_header(skb, ETH_HLEN); 548893515d53SJiri Pirko 548993515d53SJiri Pirko skb_reset_mac_len(skb); 549093515d53SJiri Pirko 549193515d53SJiri Pirko return err; 549293515d53SJiri Pirko } 5493bfca4c52SShmulik Ladkani EXPORT_SYMBOL(__skb_vlan_pop); 549493515d53SJiri Pirko 5495b6a79208SShmulik Ladkani /* Pop a vlan tag either from hwaccel or from payload. 5496b6a79208SShmulik Ladkani * Expects skb->data at mac header. 5497b6a79208SShmulik Ladkani */ 549893515d53SJiri Pirko int skb_vlan_pop(struct sk_buff *skb) 549993515d53SJiri Pirko { 550093515d53SJiri Pirko u16 vlan_tci; 550193515d53SJiri Pirko __be16 vlan_proto; 550293515d53SJiri Pirko int err; 550393515d53SJiri Pirko 5504df8a39deSJiri Pirko if (likely(skb_vlan_tag_present(skb))) { 5505b1817524SMichał Mirosław __vlan_hwaccel_clear_tag(skb); 550693515d53SJiri Pirko } else { 5507ecf4ee41SShmulik Ladkani if (unlikely(!eth_type_vlan(skb->protocol))) 550893515d53SJiri Pirko return 0; 550993515d53SJiri Pirko 551093515d53SJiri Pirko err = __skb_vlan_pop(skb, &vlan_tci); 551193515d53SJiri Pirko if (err) 551293515d53SJiri Pirko return err; 551393515d53SJiri Pirko } 551493515d53SJiri Pirko /* move next vlan tag to hw accel tag */ 5515ecf4ee41SShmulik Ladkani if (likely(!eth_type_vlan(skb->protocol))) 551693515d53SJiri Pirko return 0; 551793515d53SJiri Pirko 551893515d53SJiri Pirko vlan_proto = skb->protocol; 551993515d53SJiri Pirko err = __skb_vlan_pop(skb, &vlan_tci); 552093515d53SJiri Pirko if (unlikely(err)) 552193515d53SJiri Pirko return err; 552293515d53SJiri Pirko 552393515d53SJiri Pirko __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); 552493515d53SJiri Pirko return 0; 552593515d53SJiri Pirko } 552693515d53SJiri Pirko EXPORT_SYMBOL(skb_vlan_pop); 552793515d53SJiri Pirko 5528b6a79208SShmulik Ladkani /* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present). 5529b6a79208SShmulik Ladkani * Expects skb->data at mac header. 5530b6a79208SShmulik Ladkani */ 553193515d53SJiri Pirko int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci) 553293515d53SJiri Pirko { 5533df8a39deSJiri Pirko if (skb_vlan_tag_present(skb)) { 5534b6a79208SShmulik Ladkani int offset = skb->data - skb_mac_header(skb); 553593515d53SJiri Pirko int err; 553693515d53SJiri Pirko 5537b6a79208SShmulik Ladkani if (WARN_ONCE(offset, 5538b6a79208SShmulik Ladkani "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n", 5539b6a79208SShmulik Ladkani offset)) { 5540b6a79208SShmulik Ladkani return -EINVAL; 5541b6a79208SShmulik Ladkani } 5542b6a79208SShmulik Ladkani 554393515d53SJiri Pirko err = __vlan_insert_tag(skb, skb->vlan_proto, 5544df8a39deSJiri Pirko skb_vlan_tag_get(skb)); 5545b6a79208SShmulik Ladkani if (err) 554693515d53SJiri Pirko return err; 55479241e2dfSDaniel Borkmann 554893515d53SJiri Pirko skb->protocol = skb->vlan_proto; 554993515d53SJiri Pirko skb->mac_len += VLAN_HLEN; 555093515d53SJiri Pirko 55516b83d28aSDaniel Borkmann skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN); 555293515d53SJiri Pirko } 555393515d53SJiri Pirko __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci); 555493515d53SJiri Pirko return 0; 555593515d53SJiri Pirko } 555693515d53SJiri Pirko EXPORT_SYMBOL(skb_vlan_push); 555793515d53SJiri Pirko 555819fbcb36SGuillaume Nault /** 555919fbcb36SGuillaume Nault * skb_eth_pop() - Drop the Ethernet header at the head of a packet 556019fbcb36SGuillaume Nault * 556119fbcb36SGuillaume Nault * @skb: Socket buffer to modify 556219fbcb36SGuillaume Nault * 556319fbcb36SGuillaume Nault * Drop the Ethernet header of @skb. 556419fbcb36SGuillaume Nault * 556519fbcb36SGuillaume Nault * Expects that skb->data points to the mac header and that no VLAN tags are 556619fbcb36SGuillaume Nault * present. 556719fbcb36SGuillaume Nault * 556819fbcb36SGuillaume Nault * Returns 0 on success, -errno otherwise. 556919fbcb36SGuillaume Nault */ 557019fbcb36SGuillaume Nault int skb_eth_pop(struct sk_buff *skb) 557119fbcb36SGuillaume Nault { 557219fbcb36SGuillaume Nault if (!pskb_may_pull(skb, ETH_HLEN) || skb_vlan_tagged(skb) || 557319fbcb36SGuillaume Nault skb_network_offset(skb) < ETH_HLEN) 557419fbcb36SGuillaume Nault return -EPROTO; 557519fbcb36SGuillaume Nault 557619fbcb36SGuillaume Nault skb_pull_rcsum(skb, ETH_HLEN); 557719fbcb36SGuillaume Nault skb_reset_mac_header(skb); 557819fbcb36SGuillaume Nault skb_reset_mac_len(skb); 557919fbcb36SGuillaume Nault 558019fbcb36SGuillaume Nault return 0; 558119fbcb36SGuillaume Nault } 558219fbcb36SGuillaume Nault EXPORT_SYMBOL(skb_eth_pop); 558319fbcb36SGuillaume Nault 558419fbcb36SGuillaume Nault /** 558519fbcb36SGuillaume Nault * skb_eth_push() - Add a new Ethernet header at the head of a packet 558619fbcb36SGuillaume Nault * 558719fbcb36SGuillaume Nault * @skb: Socket buffer to modify 558819fbcb36SGuillaume Nault * @dst: Destination MAC address of the new header 558919fbcb36SGuillaume Nault * @src: Source MAC address of the new header 559019fbcb36SGuillaume Nault * 559119fbcb36SGuillaume Nault * Prepend @skb with a new Ethernet header. 559219fbcb36SGuillaume Nault * 559319fbcb36SGuillaume Nault * Expects that skb->data points to the mac header, which must be empty. 559419fbcb36SGuillaume Nault * 559519fbcb36SGuillaume Nault * Returns 0 on success, -errno otherwise. 559619fbcb36SGuillaume Nault */ 559719fbcb36SGuillaume Nault int skb_eth_push(struct sk_buff *skb, const unsigned char *dst, 559819fbcb36SGuillaume Nault const unsigned char *src) 559919fbcb36SGuillaume Nault { 560019fbcb36SGuillaume Nault struct ethhdr *eth; 560119fbcb36SGuillaume Nault int err; 560219fbcb36SGuillaume Nault 560319fbcb36SGuillaume Nault if (skb_network_offset(skb) || skb_vlan_tag_present(skb)) 560419fbcb36SGuillaume Nault return -EPROTO; 560519fbcb36SGuillaume Nault 560619fbcb36SGuillaume Nault err = skb_cow_head(skb, sizeof(*eth)); 560719fbcb36SGuillaume Nault if (err < 0) 560819fbcb36SGuillaume Nault return err; 560919fbcb36SGuillaume Nault 561019fbcb36SGuillaume Nault skb_push(skb, sizeof(*eth)); 561119fbcb36SGuillaume Nault skb_reset_mac_header(skb); 561219fbcb36SGuillaume Nault skb_reset_mac_len(skb); 561319fbcb36SGuillaume Nault 561419fbcb36SGuillaume Nault eth = eth_hdr(skb); 561519fbcb36SGuillaume Nault ether_addr_copy(eth->h_dest, dst); 561619fbcb36SGuillaume Nault ether_addr_copy(eth->h_source, src); 561719fbcb36SGuillaume Nault eth->h_proto = skb->protocol; 561819fbcb36SGuillaume Nault 561919fbcb36SGuillaume Nault skb_postpush_rcsum(skb, eth, sizeof(*eth)); 562019fbcb36SGuillaume Nault 562119fbcb36SGuillaume Nault return 0; 562219fbcb36SGuillaume Nault } 562319fbcb36SGuillaume Nault EXPORT_SYMBOL(skb_eth_push); 562419fbcb36SGuillaume Nault 56258822e270SJohn Hurley /* Update the ethertype of hdr and the skb csum value if required. */ 56268822e270SJohn Hurley static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr, 56278822e270SJohn Hurley __be16 ethertype) 56288822e270SJohn Hurley { 56298822e270SJohn Hurley if (skb->ip_summed == CHECKSUM_COMPLETE) { 56308822e270SJohn Hurley __be16 diff[] = { ~hdr->h_proto, ethertype }; 56318822e270SJohn Hurley 56328822e270SJohn Hurley skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); 56338822e270SJohn Hurley } 56348822e270SJohn Hurley 56358822e270SJohn Hurley hdr->h_proto = ethertype; 56368822e270SJohn Hurley } 56378822e270SJohn Hurley 56388822e270SJohn Hurley /** 5639e7dbfed1SMartin Varghese * skb_mpls_push() - push a new MPLS header after mac_len bytes from start of 5640e7dbfed1SMartin Varghese * the packet 56418822e270SJohn Hurley * 56428822e270SJohn Hurley * @skb: buffer 56438822e270SJohn Hurley * @mpls_lse: MPLS label stack entry to push 56448822e270SJohn Hurley * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848) 5645fa4e0f88SDavide Caratti * @mac_len: length of the MAC header 5646e7dbfed1SMartin Varghese * @ethernet: flag to indicate if the resulting packet after skb_mpls_push is 5647e7dbfed1SMartin Varghese * ethernet 56488822e270SJohn Hurley * 56498822e270SJohn Hurley * Expects skb->data at mac header. 56508822e270SJohn Hurley * 56518822e270SJohn Hurley * Returns 0 on success, -errno otherwise. 56528822e270SJohn Hurley */ 5653fa4e0f88SDavide Caratti int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto, 5654d04ac224SMartin Varghese int mac_len, bool ethernet) 56558822e270SJohn Hurley { 56568822e270SJohn Hurley struct mpls_shim_hdr *lse; 56578822e270SJohn Hurley int err; 56588822e270SJohn Hurley 56598822e270SJohn Hurley if (unlikely(!eth_p_mpls(mpls_proto))) 56608822e270SJohn Hurley return -EINVAL; 56618822e270SJohn Hurley 56628822e270SJohn Hurley /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */ 56638822e270SJohn Hurley if (skb->encapsulation) 56648822e270SJohn Hurley return -EINVAL; 56658822e270SJohn Hurley 56668822e270SJohn Hurley err = skb_cow_head(skb, MPLS_HLEN); 56678822e270SJohn Hurley if (unlikely(err)) 56688822e270SJohn Hurley return err; 56698822e270SJohn Hurley 56708822e270SJohn Hurley if (!skb->inner_protocol) { 5671e7dbfed1SMartin Varghese skb_set_inner_network_header(skb, skb_network_offset(skb)); 56728822e270SJohn Hurley skb_set_inner_protocol(skb, skb->protocol); 56738822e270SJohn Hurley } 56748822e270SJohn Hurley 56758822e270SJohn Hurley skb_push(skb, MPLS_HLEN); 56768822e270SJohn Hurley memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb), 5677fa4e0f88SDavide Caratti mac_len); 56788822e270SJohn Hurley skb_reset_mac_header(skb); 5679fa4e0f88SDavide Caratti skb_set_network_header(skb, mac_len); 5680e7dbfed1SMartin Varghese skb_reset_mac_len(skb); 56818822e270SJohn Hurley 56828822e270SJohn Hurley lse = mpls_hdr(skb); 56838822e270SJohn Hurley lse->label_stack_entry = mpls_lse; 56848822e270SJohn Hurley skb_postpush_rcsum(skb, lse, MPLS_HLEN); 56858822e270SJohn Hurley 56864296adc3SGuillaume Nault if (ethernet && mac_len >= ETH_HLEN) 56878822e270SJohn Hurley skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto); 56888822e270SJohn Hurley skb->protocol = mpls_proto; 56898822e270SJohn Hurley 56908822e270SJohn Hurley return 0; 56918822e270SJohn Hurley } 56928822e270SJohn Hurley EXPORT_SYMBOL_GPL(skb_mpls_push); 56938822e270SJohn Hurley 56942e4e4410SEric Dumazet /** 5695ed246ceeSJohn Hurley * skb_mpls_pop() - pop the outermost MPLS header 5696ed246ceeSJohn Hurley * 5697ed246ceeSJohn Hurley * @skb: buffer 5698ed246ceeSJohn Hurley * @next_proto: ethertype of header after popped MPLS header 5699fa4e0f88SDavide Caratti * @mac_len: length of the MAC header 570076f99f98SMartin Varghese * @ethernet: flag to indicate if the packet is ethernet 5701ed246ceeSJohn Hurley * 5702ed246ceeSJohn Hurley * Expects skb->data at mac header. 5703ed246ceeSJohn Hurley * 5704ed246ceeSJohn Hurley * Returns 0 on success, -errno otherwise. 5705ed246ceeSJohn Hurley */ 5706040b5cfbSMartin Varghese int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len, 5707040b5cfbSMartin Varghese bool ethernet) 5708ed246ceeSJohn Hurley { 5709ed246ceeSJohn Hurley int err; 5710ed246ceeSJohn Hurley 5711ed246ceeSJohn Hurley if (unlikely(!eth_p_mpls(skb->protocol))) 5712dedc5a08SDavide Caratti return 0; 5713ed246ceeSJohn Hurley 5714fa4e0f88SDavide Caratti err = skb_ensure_writable(skb, mac_len + MPLS_HLEN); 5715ed246ceeSJohn Hurley if (unlikely(err)) 5716ed246ceeSJohn Hurley return err; 5717ed246ceeSJohn Hurley 5718ed246ceeSJohn Hurley skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN); 5719ed246ceeSJohn Hurley memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb), 5720fa4e0f88SDavide Caratti mac_len); 5721ed246ceeSJohn Hurley 5722ed246ceeSJohn Hurley __skb_pull(skb, MPLS_HLEN); 5723ed246ceeSJohn Hurley skb_reset_mac_header(skb); 5724fa4e0f88SDavide Caratti skb_set_network_header(skb, mac_len); 5725ed246ceeSJohn Hurley 57264296adc3SGuillaume Nault if (ethernet && mac_len >= ETH_HLEN) { 5727ed246ceeSJohn Hurley struct ethhdr *hdr; 5728ed246ceeSJohn Hurley 5729ed246ceeSJohn Hurley /* use mpls_hdr() to get ethertype to account for VLANs. */ 5730ed246ceeSJohn Hurley hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN); 5731ed246ceeSJohn Hurley skb_mod_eth_type(skb, hdr, next_proto); 5732ed246ceeSJohn Hurley } 5733ed246ceeSJohn Hurley skb->protocol = next_proto; 5734ed246ceeSJohn Hurley 5735ed246ceeSJohn Hurley return 0; 5736ed246ceeSJohn Hurley } 5737ed246ceeSJohn Hurley EXPORT_SYMBOL_GPL(skb_mpls_pop); 5738ed246ceeSJohn Hurley 5739ed246ceeSJohn Hurley /** 5740d27cf5c5SJohn Hurley * skb_mpls_update_lse() - modify outermost MPLS header and update csum 5741d27cf5c5SJohn Hurley * 5742d27cf5c5SJohn Hurley * @skb: buffer 5743d27cf5c5SJohn Hurley * @mpls_lse: new MPLS label stack entry to update to 5744d27cf5c5SJohn Hurley * 5745d27cf5c5SJohn Hurley * Expects skb->data at mac header. 5746d27cf5c5SJohn Hurley * 5747d27cf5c5SJohn Hurley * Returns 0 on success, -errno otherwise. 5748d27cf5c5SJohn Hurley */ 5749d27cf5c5SJohn Hurley int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse) 5750d27cf5c5SJohn Hurley { 5751d27cf5c5SJohn Hurley int err; 5752d27cf5c5SJohn Hurley 5753d27cf5c5SJohn Hurley if (unlikely(!eth_p_mpls(skb->protocol))) 5754d27cf5c5SJohn Hurley return -EINVAL; 5755d27cf5c5SJohn Hurley 5756d27cf5c5SJohn Hurley err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN); 5757d27cf5c5SJohn Hurley if (unlikely(err)) 5758d27cf5c5SJohn Hurley return err; 5759d27cf5c5SJohn Hurley 5760d27cf5c5SJohn Hurley if (skb->ip_summed == CHECKSUM_COMPLETE) { 5761d27cf5c5SJohn Hurley __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse }; 5762d27cf5c5SJohn Hurley 5763d27cf5c5SJohn Hurley skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum); 5764d27cf5c5SJohn Hurley } 5765d27cf5c5SJohn Hurley 5766d27cf5c5SJohn Hurley mpls_hdr(skb)->label_stack_entry = mpls_lse; 5767d27cf5c5SJohn Hurley 5768d27cf5c5SJohn Hurley return 0; 5769d27cf5c5SJohn Hurley } 5770d27cf5c5SJohn Hurley EXPORT_SYMBOL_GPL(skb_mpls_update_lse); 5771d27cf5c5SJohn Hurley 5772d27cf5c5SJohn Hurley /** 57732a2ea508SJohn Hurley * skb_mpls_dec_ttl() - decrement the TTL of the outermost MPLS header 57742a2ea508SJohn Hurley * 57752a2ea508SJohn Hurley * @skb: buffer 57762a2ea508SJohn Hurley * 57772a2ea508SJohn Hurley * Expects skb->data at mac header. 57782a2ea508SJohn Hurley * 57792a2ea508SJohn Hurley * Returns 0 on success, -errno otherwise. 57802a2ea508SJohn Hurley */ 57812a2ea508SJohn Hurley int skb_mpls_dec_ttl(struct sk_buff *skb) 57822a2ea508SJohn Hurley { 57832a2ea508SJohn Hurley u32 lse; 57842a2ea508SJohn Hurley u8 ttl; 57852a2ea508SJohn Hurley 57862a2ea508SJohn Hurley if (unlikely(!eth_p_mpls(skb->protocol))) 57872a2ea508SJohn Hurley return -EINVAL; 57882a2ea508SJohn Hurley 578913de4ed9SDavide Caratti if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN)) 579013de4ed9SDavide Caratti return -ENOMEM; 579113de4ed9SDavide Caratti 57922a2ea508SJohn Hurley lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry); 57932a2ea508SJohn Hurley ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT; 57942a2ea508SJohn Hurley if (!--ttl) 57952a2ea508SJohn Hurley return -EINVAL; 57962a2ea508SJohn Hurley 57972a2ea508SJohn Hurley lse &= ~MPLS_LS_TTL_MASK; 57982a2ea508SJohn Hurley lse |= ttl << MPLS_LS_TTL_SHIFT; 57992a2ea508SJohn Hurley 58002a2ea508SJohn Hurley return skb_mpls_update_lse(skb, cpu_to_be32(lse)); 58012a2ea508SJohn Hurley } 58022a2ea508SJohn Hurley EXPORT_SYMBOL_GPL(skb_mpls_dec_ttl); 58032a2ea508SJohn Hurley 58042a2ea508SJohn Hurley /** 58052e4e4410SEric Dumazet * alloc_skb_with_frags - allocate skb with page frags 58062e4e4410SEric Dumazet * 5807de3f0d0eSMasanari Iida * @header_len: size of linear part 5808de3f0d0eSMasanari Iida * @data_len: needed length in frags 5809de3f0d0eSMasanari Iida * @max_page_order: max page order desired. 5810de3f0d0eSMasanari Iida * @errcode: pointer to error code if any 5811de3f0d0eSMasanari Iida * @gfp_mask: allocation mask 58122e4e4410SEric Dumazet * 58132e4e4410SEric Dumazet * This can be used to allocate a paged skb, given a maximal order for frags. 58142e4e4410SEric Dumazet */ 58152e4e4410SEric Dumazet struct sk_buff *alloc_skb_with_frags(unsigned long header_len, 58162e4e4410SEric Dumazet unsigned long data_len, 58172e4e4410SEric Dumazet int max_page_order, 58182e4e4410SEric Dumazet int *errcode, 58192e4e4410SEric Dumazet gfp_t gfp_mask) 58202e4e4410SEric Dumazet { 58212e4e4410SEric Dumazet int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT; 58222e4e4410SEric Dumazet unsigned long chunk; 58232e4e4410SEric Dumazet struct sk_buff *skb; 58242e4e4410SEric Dumazet struct page *page; 58252e4e4410SEric Dumazet int i; 58262e4e4410SEric Dumazet 58272e4e4410SEric Dumazet *errcode = -EMSGSIZE; 58282e4e4410SEric Dumazet /* Note this test could be relaxed, if we succeed to allocate 58292e4e4410SEric Dumazet * high order pages... 58302e4e4410SEric Dumazet */ 58312e4e4410SEric Dumazet if (npages > MAX_SKB_FRAGS) 58322e4e4410SEric Dumazet return NULL; 58332e4e4410SEric Dumazet 58342e4e4410SEric Dumazet *errcode = -ENOBUFS; 5835f8c468e8SDavid Rientjes skb = alloc_skb(header_len, gfp_mask); 58362e4e4410SEric Dumazet if (!skb) 58372e4e4410SEric Dumazet return NULL; 58382e4e4410SEric Dumazet 58392e4e4410SEric Dumazet skb->truesize += npages << PAGE_SHIFT; 58402e4e4410SEric Dumazet 58412e4e4410SEric Dumazet for (i = 0; npages > 0; i++) { 58422e4e4410SEric Dumazet int order = max_page_order; 58432e4e4410SEric Dumazet 58442e4e4410SEric Dumazet while (order) { 58452e4e4410SEric Dumazet if (npages >= 1 << order) { 5846d0164adcSMel Gorman page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) | 58472e4e4410SEric Dumazet __GFP_COMP | 5848d14b56f5SMichal Hocko __GFP_NOWARN, 58492e4e4410SEric Dumazet order); 58502e4e4410SEric Dumazet if (page) 58512e4e4410SEric Dumazet goto fill_page; 58522e4e4410SEric Dumazet /* Do not retry other high order allocations */ 58532e4e4410SEric Dumazet order = 1; 58542e4e4410SEric Dumazet max_page_order = 0; 58552e4e4410SEric Dumazet } 58562e4e4410SEric Dumazet order--; 58572e4e4410SEric Dumazet } 58582e4e4410SEric Dumazet page = alloc_page(gfp_mask); 58592e4e4410SEric Dumazet if (!page) 58602e4e4410SEric Dumazet goto failure; 58612e4e4410SEric Dumazet fill_page: 58622e4e4410SEric Dumazet chunk = min_t(unsigned long, data_len, 58632e4e4410SEric Dumazet PAGE_SIZE << order); 58642e4e4410SEric Dumazet skb_fill_page_desc(skb, i, page, 0, chunk); 58652e4e4410SEric Dumazet data_len -= chunk; 58662e4e4410SEric Dumazet npages -= 1 << order; 58672e4e4410SEric Dumazet } 58682e4e4410SEric Dumazet return skb; 58692e4e4410SEric Dumazet 58702e4e4410SEric Dumazet failure: 58712e4e4410SEric Dumazet kfree_skb(skb); 58722e4e4410SEric Dumazet return NULL; 58732e4e4410SEric Dumazet } 58742e4e4410SEric Dumazet EXPORT_SYMBOL(alloc_skb_with_frags); 58756fa01ccdSSowmini Varadhan 58766fa01ccdSSowmini Varadhan /* carve out the first off bytes from skb when off < headlen */ 58776fa01ccdSSowmini Varadhan static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off, 58786fa01ccdSSowmini Varadhan const int headlen, gfp_t gfp_mask) 58796fa01ccdSSowmini Varadhan { 58806fa01ccdSSowmini Varadhan int i; 58816fa01ccdSSowmini Varadhan int size = skb_end_offset(skb); 58826fa01ccdSSowmini Varadhan int new_hlen = headlen - off; 58836fa01ccdSSowmini Varadhan u8 *data; 58846fa01ccdSSowmini Varadhan 58856fa01ccdSSowmini Varadhan size = SKB_DATA_ALIGN(size); 58866fa01ccdSSowmini Varadhan 58876fa01ccdSSowmini Varadhan if (skb_pfmemalloc(skb)) 58886fa01ccdSSowmini Varadhan gfp_mask |= __GFP_MEMALLOC; 58896fa01ccdSSowmini Varadhan data = kmalloc_reserve(size + 58906fa01ccdSSowmini Varadhan SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), 58916fa01ccdSSowmini Varadhan gfp_mask, NUMA_NO_NODE, NULL); 58926fa01ccdSSowmini Varadhan if (!data) 58936fa01ccdSSowmini Varadhan return -ENOMEM; 58946fa01ccdSSowmini Varadhan 58956fa01ccdSSowmini Varadhan size = SKB_WITH_OVERHEAD(ksize(data)); 58966fa01ccdSSowmini Varadhan 58976fa01ccdSSowmini Varadhan /* Copy real data, and all frags */ 58986fa01ccdSSowmini Varadhan skb_copy_from_linear_data_offset(skb, off, data, new_hlen); 58996fa01ccdSSowmini Varadhan skb->len -= off; 59006fa01ccdSSowmini Varadhan 59016fa01ccdSSowmini Varadhan memcpy((struct skb_shared_info *)(data + size), 59026fa01ccdSSowmini Varadhan skb_shinfo(skb), 59036fa01ccdSSowmini Varadhan offsetof(struct skb_shared_info, 59046fa01ccdSSowmini Varadhan frags[skb_shinfo(skb)->nr_frags])); 59056fa01ccdSSowmini Varadhan if (skb_cloned(skb)) { 59066fa01ccdSSowmini Varadhan /* drop the old head gracefully */ 59076fa01ccdSSowmini Varadhan if (skb_orphan_frags(skb, gfp_mask)) { 59086fa01ccdSSowmini Varadhan kfree(data); 59096fa01ccdSSowmini Varadhan return -ENOMEM; 59106fa01ccdSSowmini Varadhan } 59116fa01ccdSSowmini Varadhan for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 59126fa01ccdSSowmini Varadhan skb_frag_ref(skb, i); 59136fa01ccdSSowmini Varadhan if (skb_has_frag_list(skb)) 59146fa01ccdSSowmini Varadhan skb_clone_fraglist(skb); 59156fa01ccdSSowmini Varadhan skb_release_data(skb); 59166fa01ccdSSowmini Varadhan } else { 59176fa01ccdSSowmini Varadhan /* we can reuse existing recount- all we did was 59186fa01ccdSSowmini Varadhan * relocate values 59196fa01ccdSSowmini Varadhan */ 59206fa01ccdSSowmini Varadhan skb_free_head(skb); 59216fa01ccdSSowmini Varadhan } 59226fa01ccdSSowmini Varadhan 59236fa01ccdSSowmini Varadhan skb->head = data; 59246fa01ccdSSowmini Varadhan skb->data = data; 59256fa01ccdSSowmini Varadhan skb->head_frag = 0; 59266fa01ccdSSowmini Varadhan #ifdef NET_SKBUFF_DATA_USES_OFFSET 59276fa01ccdSSowmini Varadhan skb->end = size; 59286fa01ccdSSowmini Varadhan #else 59296fa01ccdSSowmini Varadhan skb->end = skb->head + size; 59306fa01ccdSSowmini Varadhan #endif 59316fa01ccdSSowmini Varadhan skb_set_tail_pointer(skb, skb_headlen(skb)); 59326fa01ccdSSowmini Varadhan skb_headers_offset_update(skb, 0); 59336fa01ccdSSowmini Varadhan skb->cloned = 0; 59346fa01ccdSSowmini Varadhan skb->hdr_len = 0; 59356fa01ccdSSowmini Varadhan skb->nohdr = 0; 59366fa01ccdSSowmini Varadhan atomic_set(&skb_shinfo(skb)->dataref, 1); 59376fa01ccdSSowmini Varadhan 59386fa01ccdSSowmini Varadhan return 0; 59396fa01ccdSSowmini Varadhan } 59406fa01ccdSSowmini Varadhan 59416fa01ccdSSowmini Varadhan static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp); 59426fa01ccdSSowmini Varadhan 59436fa01ccdSSowmini Varadhan /* carve out the first eat bytes from skb's frag_list. May recurse into 59446fa01ccdSSowmini Varadhan * pskb_carve() 59456fa01ccdSSowmini Varadhan */ 59466fa01ccdSSowmini Varadhan static int pskb_carve_frag_list(struct sk_buff *skb, 59476fa01ccdSSowmini Varadhan struct skb_shared_info *shinfo, int eat, 59486fa01ccdSSowmini Varadhan gfp_t gfp_mask) 59496fa01ccdSSowmini Varadhan { 59506fa01ccdSSowmini Varadhan struct sk_buff *list = shinfo->frag_list; 59516fa01ccdSSowmini Varadhan struct sk_buff *clone = NULL; 59526fa01ccdSSowmini Varadhan struct sk_buff *insp = NULL; 59536fa01ccdSSowmini Varadhan 59546fa01ccdSSowmini Varadhan do { 59556fa01ccdSSowmini Varadhan if (!list) { 59566fa01ccdSSowmini Varadhan pr_err("Not enough bytes to eat. Want %d\n", eat); 59576fa01ccdSSowmini Varadhan return -EFAULT; 59586fa01ccdSSowmini Varadhan } 59596fa01ccdSSowmini Varadhan if (list->len <= eat) { 59606fa01ccdSSowmini Varadhan /* Eaten as whole. */ 59616fa01ccdSSowmini Varadhan eat -= list->len; 59626fa01ccdSSowmini Varadhan list = list->next; 59636fa01ccdSSowmini Varadhan insp = list; 59646fa01ccdSSowmini Varadhan } else { 59656fa01ccdSSowmini Varadhan /* Eaten partially. */ 59666fa01ccdSSowmini Varadhan if (skb_shared(list)) { 59676fa01ccdSSowmini Varadhan clone = skb_clone(list, gfp_mask); 59686fa01ccdSSowmini Varadhan if (!clone) 59696fa01ccdSSowmini Varadhan return -ENOMEM; 59706fa01ccdSSowmini Varadhan insp = list->next; 59716fa01ccdSSowmini Varadhan list = clone; 59726fa01ccdSSowmini Varadhan } else { 59736fa01ccdSSowmini Varadhan /* This may be pulled without problems. */ 59746fa01ccdSSowmini Varadhan insp = list; 59756fa01ccdSSowmini Varadhan } 59766fa01ccdSSowmini Varadhan if (pskb_carve(list, eat, gfp_mask) < 0) { 59776fa01ccdSSowmini Varadhan kfree_skb(clone); 59786fa01ccdSSowmini Varadhan return -ENOMEM; 59796fa01ccdSSowmini Varadhan } 59806fa01ccdSSowmini Varadhan break; 59816fa01ccdSSowmini Varadhan } 59826fa01ccdSSowmini Varadhan } while (eat); 59836fa01ccdSSowmini Varadhan 59846fa01ccdSSowmini Varadhan /* Free pulled out fragments. */ 59856fa01ccdSSowmini Varadhan while ((list = shinfo->frag_list) != insp) { 59866fa01ccdSSowmini Varadhan shinfo->frag_list = list->next; 59876fa01ccdSSowmini Varadhan kfree_skb(list); 59886fa01ccdSSowmini Varadhan } 59896fa01ccdSSowmini Varadhan /* And insert new clone at head. */ 59906fa01ccdSSowmini Varadhan if (clone) { 59916fa01ccdSSowmini Varadhan clone->next = list; 59926fa01ccdSSowmini Varadhan shinfo->frag_list = clone; 59936fa01ccdSSowmini Varadhan } 59946fa01ccdSSowmini Varadhan return 0; 59956fa01ccdSSowmini Varadhan } 59966fa01ccdSSowmini Varadhan 59976fa01ccdSSowmini Varadhan /* carve off first len bytes from skb. Split line (off) is in the 59986fa01ccdSSowmini Varadhan * non-linear part of skb 59996fa01ccdSSowmini Varadhan */ 60006fa01ccdSSowmini Varadhan static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off, 60016fa01ccdSSowmini Varadhan int pos, gfp_t gfp_mask) 60026fa01ccdSSowmini Varadhan { 60036fa01ccdSSowmini Varadhan int i, k = 0; 60046fa01ccdSSowmini Varadhan int size = skb_end_offset(skb); 60056fa01ccdSSowmini Varadhan u8 *data; 60066fa01ccdSSowmini Varadhan const int nfrags = skb_shinfo(skb)->nr_frags; 60076fa01ccdSSowmini Varadhan struct skb_shared_info *shinfo; 60086fa01ccdSSowmini Varadhan 60096fa01ccdSSowmini Varadhan size = SKB_DATA_ALIGN(size); 60106fa01ccdSSowmini Varadhan 60116fa01ccdSSowmini Varadhan if (skb_pfmemalloc(skb)) 60126fa01ccdSSowmini Varadhan gfp_mask |= __GFP_MEMALLOC; 60136fa01ccdSSowmini Varadhan data = kmalloc_reserve(size + 60146fa01ccdSSowmini Varadhan SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), 60156fa01ccdSSowmini Varadhan gfp_mask, NUMA_NO_NODE, NULL); 60166fa01ccdSSowmini Varadhan if (!data) 60176fa01ccdSSowmini Varadhan return -ENOMEM; 60186fa01ccdSSowmini Varadhan 60196fa01ccdSSowmini Varadhan size = SKB_WITH_OVERHEAD(ksize(data)); 60206fa01ccdSSowmini Varadhan 60216fa01ccdSSowmini Varadhan memcpy((struct skb_shared_info *)(data + size), 6022e3ec1e8cSMiaohe Lin skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0])); 60236fa01ccdSSowmini Varadhan if (skb_orphan_frags(skb, gfp_mask)) { 60246fa01ccdSSowmini Varadhan kfree(data); 60256fa01ccdSSowmini Varadhan return -ENOMEM; 60266fa01ccdSSowmini Varadhan } 60276fa01ccdSSowmini Varadhan shinfo = (struct skb_shared_info *)(data + size); 60286fa01ccdSSowmini Varadhan for (i = 0; i < nfrags; i++) { 60296fa01ccdSSowmini Varadhan int fsize = skb_frag_size(&skb_shinfo(skb)->frags[i]); 60306fa01ccdSSowmini Varadhan 60316fa01ccdSSowmini Varadhan if (pos + fsize > off) { 60326fa01ccdSSowmini Varadhan shinfo->frags[k] = skb_shinfo(skb)->frags[i]; 60336fa01ccdSSowmini Varadhan 60346fa01ccdSSowmini Varadhan if (pos < off) { 60356fa01ccdSSowmini Varadhan /* Split frag. 60366fa01ccdSSowmini Varadhan * We have two variants in this case: 60376fa01ccdSSowmini Varadhan * 1. Move all the frag to the second 60386fa01ccdSSowmini Varadhan * part, if it is possible. F.e. 60396fa01ccdSSowmini Varadhan * this approach is mandatory for TUX, 60406fa01ccdSSowmini Varadhan * where splitting is expensive. 60416fa01ccdSSowmini Varadhan * 2. Split is accurately. We make this. 60426fa01ccdSSowmini Varadhan */ 6043b54c9d5bSJonathan Lemon skb_frag_off_add(&shinfo->frags[0], off - pos); 60446fa01ccdSSowmini Varadhan skb_frag_size_sub(&shinfo->frags[0], off - pos); 60456fa01ccdSSowmini Varadhan } 60466fa01ccdSSowmini Varadhan skb_frag_ref(skb, i); 60476fa01ccdSSowmini Varadhan k++; 60486fa01ccdSSowmini Varadhan } 60496fa01ccdSSowmini Varadhan pos += fsize; 60506fa01ccdSSowmini Varadhan } 60516fa01ccdSSowmini Varadhan shinfo->nr_frags = k; 60526fa01ccdSSowmini Varadhan if (skb_has_frag_list(skb)) 60536fa01ccdSSowmini Varadhan skb_clone_fraglist(skb); 60546fa01ccdSSowmini Varadhan 60556fa01ccdSSowmini Varadhan /* split line is in frag list */ 6056eabe8618SMiaohe Lin if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) { 6057eabe8618SMiaohe Lin /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */ 6058eabe8618SMiaohe Lin if (skb_has_frag_list(skb)) 6059eabe8618SMiaohe Lin kfree_skb_list(skb_shinfo(skb)->frag_list); 6060eabe8618SMiaohe Lin kfree(data); 6061eabe8618SMiaohe Lin return -ENOMEM; 60626fa01ccdSSowmini Varadhan } 60636fa01ccdSSowmini Varadhan skb_release_data(skb); 60646fa01ccdSSowmini Varadhan 60656fa01ccdSSowmini Varadhan skb->head = data; 60666fa01ccdSSowmini Varadhan skb->head_frag = 0; 60676fa01ccdSSowmini Varadhan skb->data = data; 60686fa01ccdSSowmini Varadhan #ifdef NET_SKBUFF_DATA_USES_OFFSET 60696fa01ccdSSowmini Varadhan skb->end = size; 60706fa01ccdSSowmini Varadhan #else 60716fa01ccdSSowmini Varadhan skb->end = skb->head + size; 60726fa01ccdSSowmini Varadhan #endif 60736fa01ccdSSowmini Varadhan skb_reset_tail_pointer(skb); 60746fa01ccdSSowmini Varadhan skb_headers_offset_update(skb, 0); 60756fa01ccdSSowmini Varadhan skb->cloned = 0; 60766fa01ccdSSowmini Varadhan skb->hdr_len = 0; 60776fa01ccdSSowmini Varadhan skb->nohdr = 0; 60786fa01ccdSSowmini Varadhan skb->len -= off; 60796fa01ccdSSowmini Varadhan skb->data_len = skb->len; 60806fa01ccdSSowmini Varadhan atomic_set(&skb_shinfo(skb)->dataref, 1); 60816fa01ccdSSowmini Varadhan return 0; 60826fa01ccdSSowmini Varadhan } 60836fa01ccdSSowmini Varadhan 60846fa01ccdSSowmini Varadhan /* remove len bytes from the beginning of the skb */ 60856fa01ccdSSowmini Varadhan static int pskb_carve(struct sk_buff *skb, const u32 len, gfp_t gfp) 60866fa01ccdSSowmini Varadhan { 60876fa01ccdSSowmini Varadhan int headlen = skb_headlen(skb); 60886fa01ccdSSowmini Varadhan 60896fa01ccdSSowmini Varadhan if (len < headlen) 60906fa01ccdSSowmini Varadhan return pskb_carve_inside_header(skb, len, headlen, gfp); 60916fa01ccdSSowmini Varadhan else 60926fa01ccdSSowmini Varadhan return pskb_carve_inside_nonlinear(skb, len, headlen, gfp); 60936fa01ccdSSowmini Varadhan } 60946fa01ccdSSowmini Varadhan 60956fa01ccdSSowmini Varadhan /* Extract to_copy bytes starting at off from skb, and return this in 60966fa01ccdSSowmini Varadhan * a new skb 60976fa01ccdSSowmini Varadhan */ 60986fa01ccdSSowmini Varadhan struct sk_buff *pskb_extract(struct sk_buff *skb, int off, 60996fa01ccdSSowmini Varadhan int to_copy, gfp_t gfp) 61006fa01ccdSSowmini Varadhan { 61016fa01ccdSSowmini Varadhan struct sk_buff *clone = skb_clone(skb, gfp); 61026fa01ccdSSowmini Varadhan 61036fa01ccdSSowmini Varadhan if (!clone) 61046fa01ccdSSowmini Varadhan return NULL; 61056fa01ccdSSowmini Varadhan 61066fa01ccdSSowmini Varadhan if (pskb_carve(clone, off, gfp) < 0 || 61076fa01ccdSSowmini Varadhan pskb_trim(clone, to_copy)) { 61086fa01ccdSSowmini Varadhan kfree_skb(clone); 61096fa01ccdSSowmini Varadhan return NULL; 61106fa01ccdSSowmini Varadhan } 61116fa01ccdSSowmini Varadhan return clone; 61126fa01ccdSSowmini Varadhan } 61136fa01ccdSSowmini Varadhan EXPORT_SYMBOL(pskb_extract); 6114c8c8b127SEric Dumazet 6115c8c8b127SEric Dumazet /** 6116c8c8b127SEric Dumazet * skb_condense - try to get rid of fragments/frag_list if possible 6117c8c8b127SEric Dumazet * @skb: buffer 6118c8c8b127SEric Dumazet * 6119c8c8b127SEric Dumazet * Can be used to save memory before skb is added to a busy queue. 6120c8c8b127SEric Dumazet * If packet has bytes in frags and enough tail room in skb->head, 6121c8c8b127SEric Dumazet * pull all of them, so that we can free the frags right now and adjust 6122c8c8b127SEric Dumazet * truesize. 6123c8c8b127SEric Dumazet * Notes: 6124c8c8b127SEric Dumazet * We do not reallocate skb->head thus can not fail. 6125c8c8b127SEric Dumazet * Caller must re-evaluate skb->truesize if needed. 6126c8c8b127SEric Dumazet */ 6127c8c8b127SEric Dumazet void skb_condense(struct sk_buff *skb) 6128c8c8b127SEric Dumazet { 61293174fed9SEric Dumazet if (skb->data_len) { 61303174fed9SEric Dumazet if (skb->data_len > skb->end - skb->tail || 6131c8c8b127SEric Dumazet skb_cloned(skb)) 6132c8c8b127SEric Dumazet return; 6133c8c8b127SEric Dumazet 6134c8c8b127SEric Dumazet /* Nice, we can free page frag(s) right now */ 6135c8c8b127SEric Dumazet __pskb_pull_tail(skb, skb->data_len); 61363174fed9SEric Dumazet } 61373174fed9SEric Dumazet /* At this point, skb->truesize might be over estimated, 61383174fed9SEric Dumazet * because skb had a fragment, and fragments do not tell 61393174fed9SEric Dumazet * their truesize. 61403174fed9SEric Dumazet * When we pulled its content into skb->head, fragment 61413174fed9SEric Dumazet * was freed, but __pskb_pull_tail() could not possibly 61423174fed9SEric Dumazet * adjust skb->truesize, not knowing the frag truesize. 6143c8c8b127SEric Dumazet */ 6144c8c8b127SEric Dumazet skb->truesize = SKB_TRUESIZE(skb_end_offset(skb)); 6145c8c8b127SEric Dumazet } 6146df5042f4SFlorian Westphal 6147df5042f4SFlorian Westphal #ifdef CONFIG_SKB_EXTENSIONS 6148df5042f4SFlorian Westphal static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id) 6149df5042f4SFlorian Westphal { 6150df5042f4SFlorian Westphal return (void *)ext + (ext->offset[id] * SKB_EXT_ALIGN_VALUE); 6151df5042f4SFlorian Westphal } 6152df5042f4SFlorian Westphal 61538b69a803SPaolo Abeni /** 61548b69a803SPaolo Abeni * __skb_ext_alloc - allocate a new skb extensions storage 61558b69a803SPaolo Abeni * 61564930f483SFlorian Westphal * @flags: See kmalloc(). 61574930f483SFlorian Westphal * 61588b69a803SPaolo Abeni * Returns the newly allocated pointer. The pointer can later attached to a 61598b69a803SPaolo Abeni * skb via __skb_ext_set(). 61608b69a803SPaolo Abeni * Note: caller must handle the skb_ext as an opaque data. 61618b69a803SPaolo Abeni */ 61624930f483SFlorian Westphal struct skb_ext *__skb_ext_alloc(gfp_t flags) 6163df5042f4SFlorian Westphal { 61644930f483SFlorian Westphal struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags); 6165df5042f4SFlorian Westphal 6166df5042f4SFlorian Westphal if (new) { 6167df5042f4SFlorian Westphal memset(new->offset, 0, sizeof(new->offset)); 6168df5042f4SFlorian Westphal refcount_set(&new->refcnt, 1); 6169df5042f4SFlorian Westphal } 6170df5042f4SFlorian Westphal 6171df5042f4SFlorian Westphal return new; 6172df5042f4SFlorian Westphal } 6173df5042f4SFlorian Westphal 61744165079bSFlorian Westphal static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old, 61754165079bSFlorian Westphal unsigned int old_active) 6176df5042f4SFlorian Westphal { 6177df5042f4SFlorian Westphal struct skb_ext *new; 6178df5042f4SFlorian Westphal 6179df5042f4SFlorian Westphal if (refcount_read(&old->refcnt) == 1) 6180df5042f4SFlorian Westphal return old; 6181df5042f4SFlorian Westphal 6182df5042f4SFlorian Westphal new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC); 6183df5042f4SFlorian Westphal if (!new) 6184df5042f4SFlorian Westphal return NULL; 6185df5042f4SFlorian Westphal 6186df5042f4SFlorian Westphal memcpy(new, old, old->chunks * SKB_EXT_ALIGN_VALUE); 6187df5042f4SFlorian Westphal refcount_set(&new->refcnt, 1); 6188df5042f4SFlorian Westphal 61894165079bSFlorian Westphal #ifdef CONFIG_XFRM 61904165079bSFlorian Westphal if (old_active & (1 << SKB_EXT_SEC_PATH)) { 61914165079bSFlorian Westphal struct sec_path *sp = skb_ext_get_ptr(old, SKB_EXT_SEC_PATH); 61924165079bSFlorian Westphal unsigned int i; 61934165079bSFlorian Westphal 61944165079bSFlorian Westphal for (i = 0; i < sp->len; i++) 61954165079bSFlorian Westphal xfrm_state_hold(sp->xvec[i]); 61964165079bSFlorian Westphal } 61974165079bSFlorian Westphal #endif 6198df5042f4SFlorian Westphal __skb_ext_put(old); 6199df5042f4SFlorian Westphal return new; 6200df5042f4SFlorian Westphal } 6201df5042f4SFlorian Westphal 6202df5042f4SFlorian Westphal /** 62038b69a803SPaolo Abeni * __skb_ext_set - attach the specified extension storage to this skb 62048b69a803SPaolo Abeni * @skb: buffer 62058b69a803SPaolo Abeni * @id: extension id 62068b69a803SPaolo Abeni * @ext: extension storage previously allocated via __skb_ext_alloc() 62078b69a803SPaolo Abeni * 62088b69a803SPaolo Abeni * Existing extensions, if any, are cleared. 62098b69a803SPaolo Abeni * 62108b69a803SPaolo Abeni * Returns the pointer to the extension. 62118b69a803SPaolo Abeni */ 62128b69a803SPaolo Abeni void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id, 62138b69a803SPaolo Abeni struct skb_ext *ext) 62148b69a803SPaolo Abeni { 62158b69a803SPaolo Abeni unsigned int newlen, newoff = SKB_EXT_CHUNKSIZEOF(*ext); 62168b69a803SPaolo Abeni 62178b69a803SPaolo Abeni skb_ext_put(skb); 62188b69a803SPaolo Abeni newlen = newoff + skb_ext_type_len[id]; 62198b69a803SPaolo Abeni ext->chunks = newlen; 62208b69a803SPaolo Abeni ext->offset[id] = newoff; 62218b69a803SPaolo Abeni skb->extensions = ext; 62228b69a803SPaolo Abeni skb->active_extensions = 1 << id; 62238b69a803SPaolo Abeni return skb_ext_get_ptr(ext, id); 62248b69a803SPaolo Abeni } 62258b69a803SPaolo Abeni 62268b69a803SPaolo Abeni /** 6227df5042f4SFlorian Westphal * skb_ext_add - allocate space for given extension, COW if needed 6228df5042f4SFlorian Westphal * @skb: buffer 6229df5042f4SFlorian Westphal * @id: extension to allocate space for 6230df5042f4SFlorian Westphal * 6231df5042f4SFlorian Westphal * Allocates enough space for the given extension. 6232df5042f4SFlorian Westphal * If the extension is already present, a pointer to that extension 6233df5042f4SFlorian Westphal * is returned. 6234df5042f4SFlorian Westphal * 6235df5042f4SFlorian Westphal * If the skb was cloned, COW applies and the returned memory can be 6236df5042f4SFlorian Westphal * modified without changing the extension space of clones buffers. 6237df5042f4SFlorian Westphal * 6238df5042f4SFlorian Westphal * Returns pointer to the extension or NULL on allocation failure. 6239df5042f4SFlorian Westphal */ 6240df5042f4SFlorian Westphal void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id) 6241df5042f4SFlorian Westphal { 6242df5042f4SFlorian Westphal struct skb_ext *new, *old = NULL; 6243df5042f4SFlorian Westphal unsigned int newlen, newoff; 6244df5042f4SFlorian Westphal 6245df5042f4SFlorian Westphal if (skb->active_extensions) { 6246df5042f4SFlorian Westphal old = skb->extensions; 6247df5042f4SFlorian Westphal 62484165079bSFlorian Westphal new = skb_ext_maybe_cow(old, skb->active_extensions); 6249df5042f4SFlorian Westphal if (!new) 6250df5042f4SFlorian Westphal return NULL; 6251df5042f4SFlorian Westphal 6252682ec859SPaolo Abeni if (__skb_ext_exist(new, id)) 6253df5042f4SFlorian Westphal goto set_active; 6254df5042f4SFlorian Westphal 6255e94e50bdSPaolo Abeni newoff = new->chunks; 6256df5042f4SFlorian Westphal } else { 6257df5042f4SFlorian Westphal newoff = SKB_EXT_CHUNKSIZEOF(*new); 6258df5042f4SFlorian Westphal 62594930f483SFlorian Westphal new = __skb_ext_alloc(GFP_ATOMIC); 6260df5042f4SFlorian Westphal if (!new) 6261df5042f4SFlorian Westphal return NULL; 6262df5042f4SFlorian Westphal } 6263df5042f4SFlorian Westphal 6264df5042f4SFlorian Westphal newlen = newoff + skb_ext_type_len[id]; 6265df5042f4SFlorian Westphal new->chunks = newlen; 6266df5042f4SFlorian Westphal new->offset[id] = newoff; 6267df5042f4SFlorian Westphal set_active: 6268682ec859SPaolo Abeni skb->extensions = new; 6269df5042f4SFlorian Westphal skb->active_extensions |= 1 << id; 6270df5042f4SFlorian Westphal return skb_ext_get_ptr(new, id); 6271df5042f4SFlorian Westphal } 6272df5042f4SFlorian Westphal EXPORT_SYMBOL(skb_ext_add); 6273df5042f4SFlorian Westphal 62744165079bSFlorian Westphal #ifdef CONFIG_XFRM 62754165079bSFlorian Westphal static void skb_ext_put_sp(struct sec_path *sp) 62764165079bSFlorian Westphal { 62774165079bSFlorian Westphal unsigned int i; 62784165079bSFlorian Westphal 62794165079bSFlorian Westphal for (i = 0; i < sp->len; i++) 62804165079bSFlorian Westphal xfrm_state_put(sp->xvec[i]); 62814165079bSFlorian Westphal } 62824165079bSFlorian Westphal #endif 62834165079bSFlorian Westphal 6284df5042f4SFlorian Westphal void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id) 6285df5042f4SFlorian Westphal { 6286df5042f4SFlorian Westphal struct skb_ext *ext = skb->extensions; 6287df5042f4SFlorian Westphal 6288df5042f4SFlorian Westphal skb->active_extensions &= ~(1 << id); 6289df5042f4SFlorian Westphal if (skb->active_extensions == 0) { 6290df5042f4SFlorian Westphal skb->extensions = NULL; 6291df5042f4SFlorian Westphal __skb_ext_put(ext); 62924165079bSFlorian Westphal #ifdef CONFIG_XFRM 62934165079bSFlorian Westphal } else if (id == SKB_EXT_SEC_PATH && 62944165079bSFlorian Westphal refcount_read(&ext->refcnt) == 1) { 62954165079bSFlorian Westphal struct sec_path *sp = skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH); 62964165079bSFlorian Westphal 62974165079bSFlorian Westphal skb_ext_put_sp(sp); 62984165079bSFlorian Westphal sp->len = 0; 62994165079bSFlorian Westphal #endif 6300df5042f4SFlorian Westphal } 6301df5042f4SFlorian Westphal } 6302df5042f4SFlorian Westphal EXPORT_SYMBOL(__skb_ext_del); 6303df5042f4SFlorian Westphal 6304df5042f4SFlorian Westphal void __skb_ext_put(struct skb_ext *ext) 6305df5042f4SFlorian Westphal { 6306df5042f4SFlorian Westphal /* If this is last clone, nothing can increment 6307df5042f4SFlorian Westphal * it after check passes. Avoids one atomic op. 6308df5042f4SFlorian Westphal */ 6309df5042f4SFlorian Westphal if (refcount_read(&ext->refcnt) == 1) 6310df5042f4SFlorian Westphal goto free_now; 6311df5042f4SFlorian Westphal 6312df5042f4SFlorian Westphal if (!refcount_dec_and_test(&ext->refcnt)) 6313df5042f4SFlorian Westphal return; 6314df5042f4SFlorian Westphal free_now: 63154165079bSFlorian Westphal #ifdef CONFIG_XFRM 63164165079bSFlorian Westphal if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH)) 63174165079bSFlorian Westphal skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH)); 63184165079bSFlorian Westphal #endif 63194165079bSFlorian Westphal 6320df5042f4SFlorian Westphal kmem_cache_free(skbuff_ext_cache, ext); 6321df5042f4SFlorian Westphal } 6322df5042f4SFlorian Westphal EXPORT_SYMBOL(__skb_ext_put); 6323df5042f4SFlorian Westphal #endif /* CONFIG_SKB_EXTENSIONS */ 6324