11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * Routines having to do with the 'struct sk_buff' memory handlers. 31da177e4SLinus Torvalds * 4113aa838SAlan Cox * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> 51da177e4SLinus Torvalds * Florian La Roche <rzsfl@rz.uni-sb.de> 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * Fixes: 81da177e4SLinus Torvalds * Alan Cox : Fixed the worst of the load 91da177e4SLinus Torvalds * balancer bugs. 101da177e4SLinus Torvalds * Dave Platt : Interrupt stacking fix. 111da177e4SLinus Torvalds * Richard Kooijman : Timestamp fixes. 121da177e4SLinus Torvalds * Alan Cox : Changed buffer format. 131da177e4SLinus Torvalds * Alan Cox : destructor hook for AF_UNIX etc. 141da177e4SLinus Torvalds * Linus Torvalds : Better skb_clone. 151da177e4SLinus Torvalds * Alan Cox : Added skb_copy. 161da177e4SLinus Torvalds * Alan Cox : Added all the changed routines Linus 171da177e4SLinus Torvalds * only put in the headers 181da177e4SLinus Torvalds * Ray VanTassle : Fixed --skb->lock in free 191da177e4SLinus Torvalds * Alan Cox : skb_copy copy arp field 201da177e4SLinus Torvalds * Andi Kleen : slabified it. 211da177e4SLinus Torvalds * Robert Olsson : Removed skb_head_pool 221da177e4SLinus Torvalds * 231da177e4SLinus Torvalds * NOTE: 241da177e4SLinus Torvalds * The __skb_ routines should be called with interrupts 251da177e4SLinus Torvalds * disabled, or you better be *real* sure that the operation is atomic 261da177e4SLinus Torvalds * with respect to whatever list is being frobbed (e.g. via lock_sock() 271da177e4SLinus Torvalds * or via disabling bottom half handlers, etc). 281da177e4SLinus Torvalds * 291da177e4SLinus Torvalds * This program is free software; you can redistribute it and/or 301da177e4SLinus Torvalds * modify it under the terms of the GNU General Public License 311da177e4SLinus Torvalds * as published by the Free Software Foundation; either version 321da177e4SLinus Torvalds * 2 of the License, or (at your option) any later version. 331da177e4SLinus Torvalds */ 341da177e4SLinus Torvalds 351da177e4SLinus Torvalds /* 361da177e4SLinus Torvalds * The functions in this file will not compile correctly with gcc 2.4.x 371da177e4SLinus Torvalds */ 381da177e4SLinus Torvalds 391da177e4SLinus Torvalds #include <linux/module.h> 401da177e4SLinus Torvalds #include <linux/types.h> 411da177e4SLinus Torvalds #include <linux/kernel.h> 42fe55f6d5SVegard Nossum #include <linux/kmemcheck.h> 431da177e4SLinus Torvalds #include <linux/mm.h> 441da177e4SLinus Torvalds #include <linux/interrupt.h> 451da177e4SLinus Torvalds #include <linux/in.h> 461da177e4SLinus Torvalds #include <linux/inet.h> 471da177e4SLinus Torvalds #include <linux/slab.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> 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds #include <net/protocol.h> 631da177e4SLinus Torvalds #include <net/dst.h> 641da177e4SLinus Torvalds #include <net/sock.h> 651da177e4SLinus Torvalds #include <net/checksum.h> 661da177e4SLinus Torvalds #include <net/xfrm.h> 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds #include <asm/uaccess.h> 691da177e4SLinus Torvalds #include <asm/system.h> 70ad8d75ffSSteven Rostedt #include <trace/events/skb.h> 711da177e4SLinus Torvalds 72a1f8e7f7SAl Viro #include "kmap_skb.h" 73a1f8e7f7SAl Viro 74e18b890bSChristoph Lameter static struct kmem_cache *skbuff_head_cache __read_mostly; 75e18b890bSChristoph Lameter static struct kmem_cache *skbuff_fclone_cache __read_mostly; 761da177e4SLinus Torvalds 779c55e01cSJens Axboe static void sock_pipe_buf_release(struct pipe_inode_info *pipe, 789c55e01cSJens Axboe struct pipe_buffer *buf) 799c55e01cSJens Axboe { 808b9d3728SJarek Poplawski put_page(buf->page); 819c55e01cSJens Axboe } 829c55e01cSJens Axboe 839c55e01cSJens Axboe static void sock_pipe_buf_get(struct pipe_inode_info *pipe, 849c55e01cSJens Axboe struct pipe_buffer *buf) 859c55e01cSJens Axboe { 868b9d3728SJarek Poplawski get_page(buf->page); 879c55e01cSJens Axboe } 889c55e01cSJens Axboe 899c55e01cSJens Axboe static int sock_pipe_buf_steal(struct pipe_inode_info *pipe, 909c55e01cSJens Axboe struct pipe_buffer *buf) 919c55e01cSJens Axboe { 929c55e01cSJens Axboe return 1; 939c55e01cSJens Axboe } 949c55e01cSJens Axboe 959c55e01cSJens Axboe 969c55e01cSJens Axboe /* Pipe buffer operations for a socket. */ 9728dfef8fSAlexey Dobriyan static const struct pipe_buf_operations sock_pipe_buf_ops = { 989c55e01cSJens Axboe .can_merge = 0, 999c55e01cSJens Axboe .map = generic_pipe_buf_map, 1009c55e01cSJens Axboe .unmap = generic_pipe_buf_unmap, 1019c55e01cSJens Axboe .confirm = generic_pipe_buf_confirm, 1029c55e01cSJens Axboe .release = sock_pipe_buf_release, 1039c55e01cSJens Axboe .steal = sock_pipe_buf_steal, 1049c55e01cSJens Axboe .get = sock_pipe_buf_get, 1059c55e01cSJens Axboe }; 1069c55e01cSJens Axboe 1071da177e4SLinus Torvalds /* 1081da177e4SLinus Torvalds * Keep out-of-line to prevent kernel bloat. 1091da177e4SLinus Torvalds * __builtin_return_address is not used because it is not always 1101da177e4SLinus Torvalds * reliable. 1111da177e4SLinus Torvalds */ 1121da177e4SLinus Torvalds 1131da177e4SLinus Torvalds /** 1141da177e4SLinus Torvalds * skb_over_panic - private function 1151da177e4SLinus Torvalds * @skb: buffer 1161da177e4SLinus Torvalds * @sz: size 1171da177e4SLinus Torvalds * @here: address 1181da177e4SLinus Torvalds * 1191da177e4SLinus Torvalds * Out of line support code for skb_put(). Not user callable. 1201da177e4SLinus Torvalds */ 121ccb7c773SRami Rosen static void skb_over_panic(struct sk_buff *skb, int sz, void *here) 1221da177e4SLinus Torvalds { 12326095455SPatrick McHardy printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " 1244305b541SArnaldo Carvalho de Melo "data:%p tail:%#lx end:%#lx dev:%s\n", 12527a884dcSArnaldo Carvalho de Melo here, skb->len, sz, skb->head, skb->data, 1264305b541SArnaldo Carvalho de Melo (unsigned long)skb->tail, (unsigned long)skb->end, 12726095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1281da177e4SLinus Torvalds BUG(); 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds /** 1321da177e4SLinus Torvalds * skb_under_panic - private function 1331da177e4SLinus Torvalds * @skb: buffer 1341da177e4SLinus Torvalds * @sz: size 1351da177e4SLinus Torvalds * @here: address 1361da177e4SLinus Torvalds * 1371da177e4SLinus Torvalds * Out of line support code for skb_push(). Not user callable. 1381da177e4SLinus Torvalds */ 1391da177e4SLinus Torvalds 140ccb7c773SRami Rosen static void skb_under_panic(struct sk_buff *skb, int sz, void *here) 1411da177e4SLinus Torvalds { 14226095455SPatrick McHardy printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " 1434305b541SArnaldo Carvalho de Melo "data:%p tail:%#lx end:%#lx dev:%s\n", 14427a884dcSArnaldo Carvalho de Melo here, skb->len, sz, skb->head, skb->data, 1454305b541SArnaldo Carvalho de Melo (unsigned long)skb->tail, (unsigned long)skb->end, 14626095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1471da177e4SLinus Torvalds BUG(); 1481da177e4SLinus Torvalds } 1491da177e4SLinus Torvalds 1501da177e4SLinus Torvalds /* Allocate a new skbuff. We do this ourselves so we can fill in a few 1511da177e4SLinus Torvalds * 'private' fields and also do memory statistics to find all the 1521da177e4SLinus Torvalds * [BEEP] leaks. 1531da177e4SLinus Torvalds * 1541da177e4SLinus Torvalds */ 1551da177e4SLinus Torvalds 1561da177e4SLinus Torvalds /** 157d179cd12SDavid S. Miller * __alloc_skb - allocate a network buffer 1581da177e4SLinus Torvalds * @size: size to allocate 1591da177e4SLinus Torvalds * @gfp_mask: allocation mask 160c83c2486SRandy Dunlap * @fclone: allocate from fclone cache instead of head cache 161c83c2486SRandy Dunlap * and allocate a cloned (child) skb 162b30973f8SChristoph Hellwig * @node: numa node to allocate memory on 1631da177e4SLinus Torvalds * 1641da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and a 1651da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 1661da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 1671da177e4SLinus Torvalds * 1681da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1691da177e4SLinus Torvalds * %GFP_ATOMIC. 1701da177e4SLinus Torvalds */ 171dd0fc66fSAl Viro struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, 172b30973f8SChristoph Hellwig int fclone, int node) 1731da177e4SLinus Torvalds { 174e18b890bSChristoph Lameter struct kmem_cache *cache; 1754947d3efSBenjamin LaHaise struct skb_shared_info *shinfo; 1761da177e4SLinus Torvalds struct sk_buff *skb; 1771da177e4SLinus Torvalds u8 *data; 1781da177e4SLinus Torvalds 1798798b3fbSHerbert Xu cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; 1808798b3fbSHerbert Xu 1811da177e4SLinus Torvalds /* Get the HEAD */ 182b30973f8SChristoph Hellwig skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); 1831da177e4SLinus Torvalds if (!skb) 1841da177e4SLinus Torvalds goto out; 185ec7d2f2cSEric Dumazet prefetchw(skb); 1861da177e4SLinus Torvalds 18787fb4b7bSEric Dumazet /* We do our best to align skb_shared_info on a separate cache 18887fb4b7bSEric Dumazet * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives 18987fb4b7bSEric Dumazet * aligned memory blocks, unless SLUB/SLAB debug is enabled. 19087fb4b7bSEric Dumazet * Both skb->head and skb_shared_info are cache line aligned. 19187fb4b7bSEric Dumazet */ 192bc417e30STony Lindgren size = SKB_DATA_ALIGN(size); 19387fb4b7bSEric Dumazet size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 19487fb4b7bSEric Dumazet data = kmalloc_node_track_caller(size, gfp_mask, node); 1951da177e4SLinus Torvalds if (!data) 1961da177e4SLinus Torvalds goto nodata; 19787fb4b7bSEric Dumazet /* kmalloc(size) might give us more room than requested. 19887fb4b7bSEric Dumazet * Put skb_shared_info exactly at the end of allocated zone, 19987fb4b7bSEric Dumazet * to allow max possible filling before reallocation. 20087fb4b7bSEric Dumazet */ 20187fb4b7bSEric Dumazet size = SKB_WITH_OVERHEAD(ksize(data)); 202ec7d2f2cSEric Dumazet prefetchw(data + size); 2031da177e4SLinus Torvalds 204ca0605a7SArnaldo Carvalho de Melo /* 205c8005785SJohannes Berg * Only clear those fields we need to clear, not those that we will 206c8005785SJohannes Berg * actually initialise below. Hence, don't put any more fields after 207c8005785SJohannes Berg * the tail pointer in struct sk_buff! 208ca0605a7SArnaldo Carvalho de Melo */ 209ca0605a7SArnaldo Carvalho de Melo memset(skb, 0, offsetof(struct sk_buff, tail)); 21087fb4b7bSEric Dumazet /* Account for allocated memory : skb + skb->head */ 21187fb4b7bSEric Dumazet skb->truesize = SKB_TRUESIZE(size); 2121da177e4SLinus Torvalds atomic_set(&skb->users, 1); 2131da177e4SLinus Torvalds skb->head = data; 2141da177e4SLinus Torvalds skb->data = data; 21527a884dcSArnaldo Carvalho de Melo skb_reset_tail_pointer(skb); 2164305b541SArnaldo Carvalho de Melo skb->end = skb->tail + size; 21719633e12SStephen Hemminger #ifdef NET_SKBUFF_DATA_USES_OFFSET 21819633e12SStephen Hemminger skb->mac_header = ~0U; 21919633e12SStephen Hemminger #endif 22019633e12SStephen Hemminger 2214947d3efSBenjamin LaHaise /* make sure we initialize shinfo sequentially */ 2224947d3efSBenjamin LaHaise shinfo = skb_shinfo(skb); 223ec7d2f2cSEric Dumazet memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); 2244947d3efSBenjamin LaHaise atomic_set(&shinfo->dataref, 1); 225c2aa3665SEric Dumazet kmemcheck_annotate_variable(shinfo->destructor_arg); 2264947d3efSBenjamin LaHaise 227d179cd12SDavid S. Miller if (fclone) { 228d179cd12SDavid S. Miller struct sk_buff *child = skb + 1; 229d179cd12SDavid S. Miller atomic_t *fclone_ref = (atomic_t *) (child + 1); 2301da177e4SLinus Torvalds 231fe55f6d5SVegard Nossum kmemcheck_annotate_bitfield(child, flags1); 232fe55f6d5SVegard Nossum kmemcheck_annotate_bitfield(child, flags2); 233d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_ORIG; 234d179cd12SDavid S. Miller atomic_set(fclone_ref, 1); 235d179cd12SDavid S. Miller 236d179cd12SDavid S. Miller child->fclone = SKB_FCLONE_UNAVAILABLE; 237d179cd12SDavid S. Miller } 2381da177e4SLinus Torvalds out: 2391da177e4SLinus Torvalds return skb; 2401da177e4SLinus Torvalds nodata: 2418798b3fbSHerbert Xu kmem_cache_free(cache, skb); 2421da177e4SLinus Torvalds skb = NULL; 2431da177e4SLinus Torvalds goto out; 2441da177e4SLinus Torvalds } 245b4ac530fSDavid S. Miller EXPORT_SYMBOL(__alloc_skb); 2461da177e4SLinus Torvalds 2471da177e4SLinus Torvalds /** 2488af27456SChristoph Hellwig * __netdev_alloc_skb - allocate an skbuff for rx on a specific device 2498af27456SChristoph Hellwig * @dev: network device to receive on 2508af27456SChristoph Hellwig * @length: length to allocate 2518af27456SChristoph Hellwig * @gfp_mask: get_free_pages mask, passed to alloc_skb 2528af27456SChristoph Hellwig * 2538af27456SChristoph Hellwig * Allocate a new &sk_buff and assign it a usage count of one. The 2548af27456SChristoph Hellwig * buffer has unspecified headroom built in. Users should allocate 2558af27456SChristoph Hellwig * the headroom they think they need without accounting for the 2568af27456SChristoph Hellwig * built in space. The built in space is used for optimisations. 2578af27456SChristoph Hellwig * 2588af27456SChristoph Hellwig * %NULL is returned if there is no free memory. 2598af27456SChristoph Hellwig */ 2608af27456SChristoph Hellwig struct sk_buff *__netdev_alloc_skb(struct net_device *dev, 2618af27456SChristoph Hellwig unsigned int length, gfp_t gfp_mask) 2628af27456SChristoph Hellwig { 2638af27456SChristoph Hellwig struct sk_buff *skb; 2648af27456SChristoph Hellwig 265564824b0SEric Dumazet skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE); 2667b2e497aSChristoph Hellwig if (likely(skb)) { 2678af27456SChristoph Hellwig skb_reserve(skb, NET_SKB_PAD); 2687b2e497aSChristoph Hellwig skb->dev = dev; 2697b2e497aSChristoph Hellwig } 2708af27456SChristoph Hellwig return skb; 2718af27456SChristoph Hellwig } 272b4ac530fSDavid S. Miller EXPORT_SYMBOL(__netdev_alloc_skb); 2731da177e4SLinus Torvalds 274654bed16SPeter Zijlstra void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, 275654bed16SPeter Zijlstra int size) 276654bed16SPeter Zijlstra { 277654bed16SPeter Zijlstra skb_fill_page_desc(skb, i, page, off, size); 278654bed16SPeter Zijlstra skb->len += size; 279654bed16SPeter Zijlstra skb->data_len += size; 280654bed16SPeter Zijlstra skb->truesize += size; 281654bed16SPeter Zijlstra } 282654bed16SPeter Zijlstra EXPORT_SYMBOL(skb_add_rx_frag); 283654bed16SPeter Zijlstra 284f58518e6SIlpo Järvinen /** 285f58518e6SIlpo Järvinen * dev_alloc_skb - allocate an skbuff for receiving 286f58518e6SIlpo Järvinen * @length: length to allocate 287f58518e6SIlpo Järvinen * 288f58518e6SIlpo Järvinen * Allocate a new &sk_buff and assign it a usage count of one. The 289f58518e6SIlpo Järvinen * buffer has unspecified headroom built in. Users should allocate 290f58518e6SIlpo Järvinen * the headroom they think they need without accounting for the 291f58518e6SIlpo Järvinen * built in space. The built in space is used for optimisations. 292f58518e6SIlpo Järvinen * 293f58518e6SIlpo Järvinen * %NULL is returned if there is no free memory. Although this function 294f58518e6SIlpo Järvinen * allocates memory it can be called from an interrupt. 295f58518e6SIlpo Järvinen */ 296f58518e6SIlpo Järvinen struct sk_buff *dev_alloc_skb(unsigned int length) 297f58518e6SIlpo Järvinen { 2981483b874SDenys Vlasenko /* 2991483b874SDenys Vlasenko * There is more code here than it seems: 300a0f55e0eSDavid S. Miller * __dev_alloc_skb is an inline 3011483b874SDenys Vlasenko */ 302f58518e6SIlpo Järvinen return __dev_alloc_skb(length, GFP_ATOMIC); 303f58518e6SIlpo Järvinen } 304f58518e6SIlpo Järvinen EXPORT_SYMBOL(dev_alloc_skb); 305f58518e6SIlpo Järvinen 30627b437c8SHerbert Xu static void skb_drop_list(struct sk_buff **listp) 3071da177e4SLinus Torvalds { 30827b437c8SHerbert Xu struct sk_buff *list = *listp; 3091da177e4SLinus Torvalds 31027b437c8SHerbert Xu *listp = NULL; 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds do { 3131da177e4SLinus Torvalds struct sk_buff *this = list; 3141da177e4SLinus Torvalds list = list->next; 3151da177e4SLinus Torvalds kfree_skb(this); 3161da177e4SLinus Torvalds } while (list); 3171da177e4SLinus Torvalds } 3181da177e4SLinus Torvalds 31927b437c8SHerbert Xu static inline void skb_drop_fraglist(struct sk_buff *skb) 32027b437c8SHerbert Xu { 32127b437c8SHerbert Xu skb_drop_list(&skb_shinfo(skb)->frag_list); 32227b437c8SHerbert Xu } 32327b437c8SHerbert Xu 3241da177e4SLinus Torvalds static void skb_clone_fraglist(struct sk_buff *skb) 3251da177e4SLinus Torvalds { 3261da177e4SLinus Torvalds struct sk_buff *list; 3271da177e4SLinus Torvalds 328fbb398a8SDavid S. Miller skb_walk_frags(skb, list) 3291da177e4SLinus Torvalds skb_get(list); 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds 3325bba1712SAdrian Bunk static void skb_release_data(struct sk_buff *skb) 3331da177e4SLinus Torvalds { 3341da177e4SLinus Torvalds if (!skb->cloned || 3351da177e4SLinus Torvalds !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, 3361da177e4SLinus Torvalds &skb_shinfo(skb)->dataref)) { 3371da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 3381da177e4SLinus Torvalds int i; 3391da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 340ea2ab693SIan Campbell skb_frag_unref(skb, i); 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds 343a6686f2fSShirley Ma /* 344a6686f2fSShirley Ma * If skb buf is from userspace, we need to notify the caller 345a6686f2fSShirley Ma * the lower device DMA has done; 346a6686f2fSShirley Ma */ 347a6686f2fSShirley Ma if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { 348a6686f2fSShirley Ma struct ubuf_info *uarg; 349a6686f2fSShirley Ma 350a6686f2fSShirley Ma uarg = skb_shinfo(skb)->destructor_arg; 351a6686f2fSShirley Ma if (uarg->callback) 352a6686f2fSShirley Ma uarg->callback(uarg); 353a6686f2fSShirley Ma } 354a6686f2fSShirley Ma 35521dc3301SDavid S. Miller if (skb_has_frag_list(skb)) 3561da177e4SLinus Torvalds skb_drop_fraglist(skb); 3571da177e4SLinus Torvalds 3581da177e4SLinus Torvalds kfree(skb->head); 3591da177e4SLinus Torvalds } 3601da177e4SLinus Torvalds } 3611da177e4SLinus Torvalds 3621da177e4SLinus Torvalds /* 3631da177e4SLinus Torvalds * Free an skbuff by memory without cleaning the state. 3641da177e4SLinus Torvalds */ 3652d4baff8SHerbert Xu static void kfree_skbmem(struct sk_buff *skb) 3661da177e4SLinus Torvalds { 367d179cd12SDavid S. Miller struct sk_buff *other; 368d179cd12SDavid S. Miller atomic_t *fclone_ref; 369d179cd12SDavid S. Miller 370d179cd12SDavid S. Miller switch (skb->fclone) { 371d179cd12SDavid S. Miller case SKB_FCLONE_UNAVAILABLE: 3721da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 373d179cd12SDavid S. Miller break; 374d179cd12SDavid S. Miller 375d179cd12SDavid S. Miller case SKB_FCLONE_ORIG: 376d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 2); 377d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 378d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, skb); 379d179cd12SDavid S. Miller break; 380d179cd12SDavid S. Miller 381d179cd12SDavid S. Miller case SKB_FCLONE_CLONE: 382d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 1); 383d179cd12SDavid S. Miller other = skb - 1; 384d179cd12SDavid S. Miller 385d179cd12SDavid S. Miller /* The clone portion is available for 386d179cd12SDavid S. Miller * fast-cloning again. 387d179cd12SDavid S. Miller */ 388d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_UNAVAILABLE; 389d179cd12SDavid S. Miller 390d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 391d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, other); 392d179cd12SDavid S. Miller break; 3933ff50b79SStephen Hemminger } 3941da177e4SLinus Torvalds } 3951da177e4SLinus Torvalds 39604a4bb55SLennert Buytenhek static void skb_release_head_state(struct sk_buff *skb) 3971da177e4SLinus Torvalds { 398adf30907SEric Dumazet skb_dst_drop(skb); 3991da177e4SLinus Torvalds #ifdef CONFIG_XFRM 4001da177e4SLinus Torvalds secpath_put(skb->sp); 4011da177e4SLinus Torvalds #endif 4021da177e4SLinus Torvalds if (skb->destructor) { 4039c2b3328SStephen Hemminger WARN_ON(in_irq()); 4041da177e4SLinus Torvalds skb->destructor(skb); 4051da177e4SLinus Torvalds } 4069fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4075f79e0f9SYasuyuki Kozakai nf_conntrack_put(skb->nfct); 4082fc72c7bSKOVACS Krisztian #endif 4092fc72c7bSKOVACS Krisztian #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED 4109fb9cbb1SYasuyuki Kozakai nf_conntrack_put_reasm(skb->nfct_reasm); 4119fb9cbb1SYasuyuki Kozakai #endif 4121da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 4131da177e4SLinus Torvalds nf_bridge_put(skb->nf_bridge); 4141da177e4SLinus Torvalds #endif 4151da177e4SLinus Torvalds /* XXX: IS this still necessary? - JHS */ 4161da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 4171da177e4SLinus Torvalds skb->tc_index = 0; 4181da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 4191da177e4SLinus Torvalds skb->tc_verd = 0; 4201da177e4SLinus Torvalds #endif 4211da177e4SLinus Torvalds #endif 42204a4bb55SLennert Buytenhek } 42304a4bb55SLennert Buytenhek 42404a4bb55SLennert Buytenhek /* Free everything but the sk_buff shell. */ 42504a4bb55SLennert Buytenhek static void skb_release_all(struct sk_buff *skb) 42604a4bb55SLennert Buytenhek { 42704a4bb55SLennert Buytenhek skb_release_head_state(skb); 4282d4baff8SHerbert Xu skb_release_data(skb); 4292d4baff8SHerbert Xu } 4301da177e4SLinus Torvalds 4312d4baff8SHerbert Xu /** 4322d4baff8SHerbert Xu * __kfree_skb - private function 4332d4baff8SHerbert Xu * @skb: buffer 4342d4baff8SHerbert Xu * 4352d4baff8SHerbert Xu * Free an sk_buff. Release anything attached to the buffer. 4362d4baff8SHerbert Xu * Clean the state. This is an internal helper function. Users should 4372d4baff8SHerbert Xu * always call kfree_skb 4382d4baff8SHerbert Xu */ 4392d4baff8SHerbert Xu 4402d4baff8SHerbert Xu void __kfree_skb(struct sk_buff *skb) 4412d4baff8SHerbert Xu { 4422d4baff8SHerbert Xu skb_release_all(skb); 4431da177e4SLinus Torvalds kfree_skbmem(skb); 4441da177e4SLinus Torvalds } 445b4ac530fSDavid S. Miller EXPORT_SYMBOL(__kfree_skb); 4461da177e4SLinus Torvalds 4471da177e4SLinus Torvalds /** 448231d06aeSJörn Engel * kfree_skb - free an sk_buff 449231d06aeSJörn Engel * @skb: buffer to free 450231d06aeSJörn Engel * 451231d06aeSJörn Engel * Drop a reference to the buffer and free it if the usage count has 452231d06aeSJörn Engel * hit zero. 453231d06aeSJörn Engel */ 454231d06aeSJörn Engel void kfree_skb(struct sk_buff *skb) 455231d06aeSJörn Engel { 456231d06aeSJörn Engel if (unlikely(!skb)) 457231d06aeSJörn Engel return; 458231d06aeSJörn Engel if (likely(atomic_read(&skb->users) == 1)) 459231d06aeSJörn Engel smp_rmb(); 460231d06aeSJörn Engel else if (likely(!atomic_dec_and_test(&skb->users))) 461231d06aeSJörn Engel return; 462ead2ceb0SNeil Horman trace_kfree_skb(skb, __builtin_return_address(0)); 463231d06aeSJörn Engel __kfree_skb(skb); 464231d06aeSJörn Engel } 465b4ac530fSDavid S. Miller EXPORT_SYMBOL(kfree_skb); 466231d06aeSJörn Engel 467d1a203eaSStephen Hemminger /** 468ead2ceb0SNeil Horman * consume_skb - free an skbuff 469ead2ceb0SNeil Horman * @skb: buffer to free 470ead2ceb0SNeil Horman * 471ead2ceb0SNeil Horman * Drop a ref to the buffer and free it if the usage count has hit zero 472ead2ceb0SNeil Horman * Functions identically to kfree_skb, but kfree_skb assumes that the frame 473ead2ceb0SNeil Horman * is being dropped after a failure and notes that 474ead2ceb0SNeil Horman */ 475ead2ceb0SNeil Horman void consume_skb(struct sk_buff *skb) 476ead2ceb0SNeil Horman { 477ead2ceb0SNeil Horman if (unlikely(!skb)) 478ead2ceb0SNeil Horman return; 479ead2ceb0SNeil Horman if (likely(atomic_read(&skb->users) == 1)) 480ead2ceb0SNeil Horman smp_rmb(); 481ead2ceb0SNeil Horman else if (likely(!atomic_dec_and_test(&skb->users))) 482ead2ceb0SNeil Horman return; 48307dc22e7SKoki Sanagi trace_consume_skb(skb); 484ead2ceb0SNeil Horman __kfree_skb(skb); 485ead2ceb0SNeil Horman } 486ead2ceb0SNeil Horman EXPORT_SYMBOL(consume_skb); 487ead2ceb0SNeil Horman 488ead2ceb0SNeil Horman /** 4893d153a7cSAndy Fleming * skb_recycle - clean up an skb for reuse 4903d153a7cSAndy Fleming * @skb: buffer 4913d153a7cSAndy Fleming * 4923d153a7cSAndy Fleming * Recycles the skb to be reused as a receive buffer. This 4933d153a7cSAndy Fleming * function does any necessary reference count dropping, and 4943d153a7cSAndy Fleming * cleans up the skbuff as if it just came from __alloc_skb(). 4953d153a7cSAndy Fleming */ 4963d153a7cSAndy Fleming void skb_recycle(struct sk_buff *skb) 4973d153a7cSAndy Fleming { 4983d153a7cSAndy Fleming struct skb_shared_info *shinfo; 4993d153a7cSAndy Fleming 5003d153a7cSAndy Fleming skb_release_head_state(skb); 5013d153a7cSAndy Fleming 5023d153a7cSAndy Fleming shinfo = skb_shinfo(skb); 5033d153a7cSAndy Fleming memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); 5043d153a7cSAndy Fleming atomic_set(&shinfo->dataref, 1); 5053d153a7cSAndy Fleming 5063d153a7cSAndy Fleming memset(skb, 0, offsetof(struct sk_buff, tail)); 5073d153a7cSAndy Fleming skb->data = skb->head + NET_SKB_PAD; 5083d153a7cSAndy Fleming skb_reset_tail_pointer(skb); 5093d153a7cSAndy Fleming } 5103d153a7cSAndy Fleming EXPORT_SYMBOL(skb_recycle); 5113d153a7cSAndy Fleming 5123d153a7cSAndy Fleming /** 513d1a203eaSStephen Hemminger * skb_recycle_check - check if skb can be reused for receive 514d1a203eaSStephen Hemminger * @skb: buffer 515d1a203eaSStephen Hemminger * @skb_size: minimum receive buffer size 516d1a203eaSStephen Hemminger * 517d1a203eaSStephen Hemminger * Checks that the skb passed in is not shared or cloned, and 518d1a203eaSStephen Hemminger * that it is linear and its head portion at least as large as 519d1a203eaSStephen Hemminger * skb_size so that it can be recycled as a receive buffer. 520d1a203eaSStephen Hemminger * If these conditions are met, this function does any necessary 521d1a203eaSStephen Hemminger * reference count dropping and cleans up the skbuff as if it 522d1a203eaSStephen Hemminger * just came from __alloc_skb(). 523d1a203eaSStephen Hemminger */ 5245b0daa34SChangli Gao bool skb_recycle_check(struct sk_buff *skb, int skb_size) 52504a4bb55SLennert Buytenhek { 5263d153a7cSAndy Fleming if (!skb_is_recycleable(skb, skb_size)) 5275b0daa34SChangli Gao return false; 528e84af6ddSAnton Vorontsov 5293d153a7cSAndy Fleming skb_recycle(skb); 53004a4bb55SLennert Buytenhek 5315b0daa34SChangli Gao return true; 53204a4bb55SLennert Buytenhek } 53304a4bb55SLennert Buytenhek EXPORT_SYMBOL(skb_recycle_check); 53404a4bb55SLennert Buytenhek 535dec18810SHerbert Xu static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 536dec18810SHerbert Xu { 537dec18810SHerbert Xu new->tstamp = old->tstamp; 538dec18810SHerbert Xu new->dev = old->dev; 539dec18810SHerbert Xu new->transport_header = old->transport_header; 540dec18810SHerbert Xu new->network_header = old->network_header; 541dec18810SHerbert Xu new->mac_header = old->mac_header; 5427fee226aSEric Dumazet skb_dst_copy(new, old); 5430a9627f2STom Herbert new->rxhash = old->rxhash; 5446461be3aSChangli Gao new->ooo_okay = old->ooo_okay; 545bdeab991STom Herbert new->l4_rxhash = old->l4_rxhash; 546def8b4faSAlexey Dobriyan #ifdef CONFIG_XFRM 547dec18810SHerbert Xu new->sp = secpath_get(old->sp); 548dec18810SHerbert Xu #endif 549dec18810SHerbert Xu memcpy(new->cb, old->cb, sizeof(old->cb)); 5509bcb97caSHerbert Xu new->csum = old->csum; 551dec18810SHerbert Xu new->local_df = old->local_df; 552dec18810SHerbert Xu new->pkt_type = old->pkt_type; 553dec18810SHerbert Xu new->ip_summed = old->ip_summed; 554dec18810SHerbert Xu skb_copy_queue_mapping(new, old); 555dec18810SHerbert Xu new->priority = old->priority; 556dec18810SHerbert Xu #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 557dec18810SHerbert Xu new->ipvs_property = old->ipvs_property; 558dec18810SHerbert Xu #endif 559dec18810SHerbert Xu new->protocol = old->protocol; 560dec18810SHerbert Xu new->mark = old->mark; 5618964be4aSEric Dumazet new->skb_iif = old->skb_iif; 562dec18810SHerbert Xu __nf_copy(new, old); 563dec18810SHerbert Xu #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ 564dec18810SHerbert Xu defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) 565dec18810SHerbert Xu new->nf_trace = old->nf_trace; 566dec18810SHerbert Xu #endif 567dec18810SHerbert Xu #ifdef CONFIG_NET_SCHED 568dec18810SHerbert Xu new->tc_index = old->tc_index; 569dec18810SHerbert Xu #ifdef CONFIG_NET_CLS_ACT 570dec18810SHerbert Xu new->tc_verd = old->tc_verd; 571dec18810SHerbert Xu #endif 572dec18810SHerbert Xu #endif 5736aa895b0SPatrick McHardy new->vlan_tci = old->vlan_tci; 5746aa895b0SPatrick McHardy 575dec18810SHerbert Xu skb_copy_secmark(new, old); 576dec18810SHerbert Xu } 577dec18810SHerbert Xu 57882c49a35SHerbert Xu /* 57982c49a35SHerbert Xu * You should not add any new code to this function. Add it to 58082c49a35SHerbert Xu * __copy_skb_header above instead. 58182c49a35SHerbert Xu */ 582e0053ec0SHerbert Xu static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) 5831da177e4SLinus Torvalds { 5841da177e4SLinus Torvalds #define C(x) n->x = skb->x 5851da177e4SLinus Torvalds 5861da177e4SLinus Torvalds n->next = n->prev = NULL; 5871da177e4SLinus Torvalds n->sk = NULL; 588dec18810SHerbert Xu __copy_skb_header(n, skb); 589dec18810SHerbert Xu 5901da177e4SLinus Torvalds C(len); 5911da177e4SLinus Torvalds C(data_len); 5923e6b3b2eSAlexey Dobriyan C(mac_len); 593334a8132SPatrick McHardy n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len; 59402f1c89dSPaul Moore n->cloned = 1; 5951da177e4SLinus Torvalds n->nohdr = 0; 5961da177e4SLinus Torvalds n->destructor = NULL; 5971da177e4SLinus Torvalds C(tail); 5981da177e4SLinus Torvalds C(end); 59902f1c89dSPaul Moore C(head); 60002f1c89dSPaul Moore C(data); 60102f1c89dSPaul Moore C(truesize); 60202f1c89dSPaul Moore atomic_set(&n->users, 1); 6031da177e4SLinus Torvalds 6041da177e4SLinus Torvalds atomic_inc(&(skb_shinfo(skb)->dataref)); 6051da177e4SLinus Torvalds skb->cloned = 1; 6061da177e4SLinus Torvalds 6071da177e4SLinus Torvalds return n; 608e0053ec0SHerbert Xu #undef C 609e0053ec0SHerbert Xu } 610e0053ec0SHerbert Xu 611e0053ec0SHerbert Xu /** 612e0053ec0SHerbert Xu * skb_morph - morph one skb into another 613e0053ec0SHerbert Xu * @dst: the skb to receive the contents 614e0053ec0SHerbert Xu * @src: the skb to supply the contents 615e0053ec0SHerbert Xu * 616e0053ec0SHerbert Xu * This is identical to skb_clone except that the target skb is 617e0053ec0SHerbert Xu * supplied by the user. 618e0053ec0SHerbert Xu * 619e0053ec0SHerbert Xu * The target skb is returned upon exit. 620e0053ec0SHerbert Xu */ 621e0053ec0SHerbert Xu struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src) 622e0053ec0SHerbert Xu { 6232d4baff8SHerbert Xu skb_release_all(dst); 624e0053ec0SHerbert Xu return __skb_clone(dst, src); 625e0053ec0SHerbert Xu } 626e0053ec0SHerbert Xu EXPORT_SYMBOL_GPL(skb_morph); 627e0053ec0SHerbert Xu 62848c83012SMichael S. Tsirkin /* skb_copy_ubufs - copy userspace skb frags buffers to kernel 62948c83012SMichael S. Tsirkin * @skb: the skb to modify 63048c83012SMichael S. Tsirkin * @gfp_mask: allocation priority 63148c83012SMichael S. Tsirkin * 63248c83012SMichael S. Tsirkin * This must be called on SKBTX_DEV_ZEROCOPY skb. 63348c83012SMichael S. Tsirkin * It will copy all frags into kernel and drop the reference 63448c83012SMichael S. Tsirkin * to userspace pages. 63548c83012SMichael S. Tsirkin * 63648c83012SMichael S. Tsirkin * If this function is called from an interrupt gfp_mask() must be 63748c83012SMichael S. Tsirkin * %GFP_ATOMIC. 63848c83012SMichael S. Tsirkin * 63948c83012SMichael S. Tsirkin * Returns 0 on success or a negative error code on failure 64048c83012SMichael S. Tsirkin * to allocate kernel memory to copy to. 64148c83012SMichael S. Tsirkin */ 64248c83012SMichael S. Tsirkin int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask) 643a6686f2fSShirley Ma { 644a6686f2fSShirley Ma int i; 645a6686f2fSShirley Ma int num_frags = skb_shinfo(skb)->nr_frags; 646a6686f2fSShirley Ma struct page *page, *head = NULL; 647a6686f2fSShirley Ma struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg; 648a6686f2fSShirley Ma 649a6686f2fSShirley Ma for (i = 0; i < num_frags; i++) { 650a6686f2fSShirley Ma u8 *vaddr; 651a6686f2fSShirley Ma skb_frag_t *f = &skb_shinfo(skb)->frags[i]; 652a6686f2fSShirley Ma 653a6686f2fSShirley Ma page = alloc_page(GFP_ATOMIC); 654a6686f2fSShirley Ma if (!page) { 655a6686f2fSShirley Ma while (head) { 656a6686f2fSShirley Ma struct page *next = (struct page *)head->private; 657a6686f2fSShirley Ma put_page(head); 658a6686f2fSShirley Ma head = next; 659a6686f2fSShirley Ma } 660a6686f2fSShirley Ma return -ENOMEM; 661a6686f2fSShirley Ma } 662a6686f2fSShirley Ma vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); 663a6686f2fSShirley Ma memcpy(page_address(page), 6649e903e08SEric Dumazet vaddr + f->page_offset, skb_frag_size(f)); 665a6686f2fSShirley Ma kunmap_skb_frag(vaddr); 666a6686f2fSShirley Ma page->private = (unsigned long)head; 667a6686f2fSShirley Ma head = page; 668a6686f2fSShirley Ma } 669a6686f2fSShirley Ma 670a6686f2fSShirley Ma /* skb frags release userspace buffers */ 671a6686f2fSShirley Ma for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 672a8605c60SIan Campbell skb_frag_unref(skb, i); 673a6686f2fSShirley Ma 674a6686f2fSShirley Ma uarg->callback(uarg); 675a6686f2fSShirley Ma 676a6686f2fSShirley Ma /* skb frags point to kernel buffers */ 677a6686f2fSShirley Ma for (i = skb_shinfo(skb)->nr_frags; i > 0; i--) { 678a8605c60SIan Campbell __skb_fill_page_desc(skb, i-1, head, 0, 679a8605c60SIan Campbell skb_shinfo(skb)->frags[i - 1].size); 680a6686f2fSShirley Ma head = (struct page *)head->private; 681a6686f2fSShirley Ma } 68248c83012SMichael S. Tsirkin 68348c83012SMichael S. Tsirkin skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY; 684a6686f2fSShirley Ma return 0; 685a6686f2fSShirley Ma } 686a6686f2fSShirley Ma 687a6686f2fSShirley Ma 688e0053ec0SHerbert Xu /** 689e0053ec0SHerbert Xu * skb_clone - duplicate an sk_buff 690e0053ec0SHerbert Xu * @skb: buffer to clone 691e0053ec0SHerbert Xu * @gfp_mask: allocation priority 692e0053ec0SHerbert Xu * 693e0053ec0SHerbert Xu * Duplicate an &sk_buff. The new one is not owned by a socket. Both 694e0053ec0SHerbert Xu * copies share the same packet data but not structure. The new 695e0053ec0SHerbert Xu * buffer has a reference count of 1. If the allocation fails the 696e0053ec0SHerbert Xu * function returns %NULL otherwise the new buffer is returned. 697e0053ec0SHerbert Xu * 698e0053ec0SHerbert Xu * If this function is called from an interrupt gfp_mask() must be 699e0053ec0SHerbert Xu * %GFP_ATOMIC. 700e0053ec0SHerbert Xu */ 701e0053ec0SHerbert Xu 702e0053ec0SHerbert Xu struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) 703e0053ec0SHerbert Xu { 704e0053ec0SHerbert Xu struct sk_buff *n; 705e0053ec0SHerbert Xu 706a6686f2fSShirley Ma if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { 707a6686f2fSShirley Ma if (skb_copy_ubufs(skb, gfp_mask)) 708a6686f2fSShirley Ma return NULL; 709a6686f2fSShirley Ma } 710a6686f2fSShirley Ma 711e0053ec0SHerbert Xu n = skb + 1; 712e0053ec0SHerbert Xu if (skb->fclone == SKB_FCLONE_ORIG && 713e0053ec0SHerbert Xu n->fclone == SKB_FCLONE_UNAVAILABLE) { 714e0053ec0SHerbert Xu atomic_t *fclone_ref = (atomic_t *) (n + 1); 715e0053ec0SHerbert Xu n->fclone = SKB_FCLONE_CLONE; 716e0053ec0SHerbert Xu atomic_inc(fclone_ref); 717e0053ec0SHerbert Xu } else { 718e0053ec0SHerbert Xu n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); 719e0053ec0SHerbert Xu if (!n) 720e0053ec0SHerbert Xu return NULL; 721fe55f6d5SVegard Nossum 722fe55f6d5SVegard Nossum kmemcheck_annotate_bitfield(n, flags1); 723fe55f6d5SVegard Nossum kmemcheck_annotate_bitfield(n, flags2); 724e0053ec0SHerbert Xu n->fclone = SKB_FCLONE_UNAVAILABLE; 725e0053ec0SHerbert Xu } 726e0053ec0SHerbert Xu 727e0053ec0SHerbert Xu return __skb_clone(n, skb); 7281da177e4SLinus Torvalds } 729b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_clone); 7301da177e4SLinus Torvalds 7311da177e4SLinus Torvalds static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 7321da177e4SLinus Torvalds { 7332e07fa9cSArnaldo Carvalho de Melo #ifndef NET_SKBUFF_DATA_USES_OFFSET 7341da177e4SLinus Torvalds /* 7351da177e4SLinus Torvalds * Shift between the two data areas in bytes 7361da177e4SLinus Torvalds */ 7371da177e4SLinus Torvalds unsigned long offset = new->data - old->data; 7382e07fa9cSArnaldo Carvalho de Melo #endif 739dec18810SHerbert Xu 740dec18810SHerbert Xu __copy_skb_header(new, old); 741dec18810SHerbert Xu 7422e07fa9cSArnaldo Carvalho de Melo #ifndef NET_SKBUFF_DATA_USES_OFFSET 7432e07fa9cSArnaldo Carvalho de Melo /* {transport,network,mac}_header are relative to skb->head */ 7442e07fa9cSArnaldo Carvalho de Melo new->transport_header += offset; 7452e07fa9cSArnaldo Carvalho de Melo new->network_header += offset; 746603a8bbeSStephen Hemminger if (skb_mac_header_was_set(new)) 7472e07fa9cSArnaldo Carvalho de Melo new->mac_header += offset; 7482e07fa9cSArnaldo Carvalho de Melo #endif 7497967168cSHerbert Xu skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; 7507967168cSHerbert Xu skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; 7517967168cSHerbert Xu skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; 7521da177e4SLinus Torvalds } 7531da177e4SLinus Torvalds 7541da177e4SLinus Torvalds /** 7551da177e4SLinus Torvalds * skb_copy - create private copy of an sk_buff 7561da177e4SLinus Torvalds * @skb: buffer to copy 7571da177e4SLinus Torvalds * @gfp_mask: allocation priority 7581da177e4SLinus Torvalds * 7591da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data. This is used when the 7601da177e4SLinus Torvalds * caller wishes to modify the data and needs a private copy of the 7611da177e4SLinus Torvalds * data to alter. Returns %NULL on failure or the pointer to the buffer 7621da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 7631da177e4SLinus Torvalds * 7641da177e4SLinus Torvalds * As by-product this function converts non-linear &sk_buff to linear 7651da177e4SLinus Torvalds * one, so that &sk_buff becomes completely private and caller is allowed 7661da177e4SLinus Torvalds * to modify all the data of returned buffer. This means that this 7671da177e4SLinus Torvalds * function is not recommended for use in circumstances when only 7681da177e4SLinus Torvalds * header is going to be modified. Use pskb_copy() instead. 7691da177e4SLinus Torvalds */ 7701da177e4SLinus Torvalds 771dd0fc66fSAl Viro struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) 7721da177e4SLinus Torvalds { 7736602cebbSEric Dumazet int headerlen = skb_headroom(skb); 7746602cebbSEric Dumazet unsigned int size = (skb_end_pointer(skb) - skb->head) + skb->data_len; 7756602cebbSEric Dumazet struct sk_buff *n = alloc_skb(size, gfp_mask); 7766602cebbSEric Dumazet 7771da177e4SLinus Torvalds if (!n) 7781da177e4SLinus Torvalds return NULL; 7791da177e4SLinus Torvalds 7801da177e4SLinus Torvalds /* Set the data pointer */ 7811da177e4SLinus Torvalds skb_reserve(n, headerlen); 7821da177e4SLinus Torvalds /* Set the tail pointer and length */ 7831da177e4SLinus Torvalds skb_put(n, skb->len); 7841da177e4SLinus Torvalds 7851da177e4SLinus Torvalds if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) 7861da177e4SLinus Torvalds BUG(); 7871da177e4SLinus Torvalds 7881da177e4SLinus Torvalds copy_skb_header(n, skb); 7891da177e4SLinus Torvalds return n; 7901da177e4SLinus Torvalds } 791b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy); 7921da177e4SLinus Torvalds 7931da177e4SLinus Torvalds /** 7941da177e4SLinus Torvalds * pskb_copy - create copy of an sk_buff with private head. 7951da177e4SLinus Torvalds * @skb: buffer to copy 7961da177e4SLinus Torvalds * @gfp_mask: allocation priority 7971da177e4SLinus Torvalds * 7981da177e4SLinus Torvalds * Make a copy of both an &sk_buff and part of its data, located 7991da177e4SLinus Torvalds * in header. Fragmented data remain shared. This is used when 8001da177e4SLinus Torvalds * the caller wishes to modify only header of &sk_buff and needs 8011da177e4SLinus Torvalds * private copy of the header to alter. Returns %NULL on failure 8021da177e4SLinus Torvalds * or the pointer to the buffer on success. 8031da177e4SLinus Torvalds * The returned buffer has a reference count of 1. 8041da177e4SLinus Torvalds */ 8051da177e4SLinus Torvalds 806dd0fc66fSAl Viro struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask) 8071da177e4SLinus Torvalds { 8086602cebbSEric Dumazet unsigned int size = skb_end_pointer(skb) - skb->head; 8096602cebbSEric Dumazet struct sk_buff *n = alloc_skb(size, gfp_mask); 8106602cebbSEric Dumazet 8111da177e4SLinus Torvalds if (!n) 8121da177e4SLinus Torvalds goto out; 8131da177e4SLinus Torvalds 8141da177e4SLinus Torvalds /* Set the data pointer */ 8156602cebbSEric Dumazet skb_reserve(n, skb_headroom(skb)); 8161da177e4SLinus Torvalds /* Set the tail pointer and length */ 8171da177e4SLinus Torvalds skb_put(n, skb_headlen(skb)); 8181da177e4SLinus Torvalds /* Copy the bytes */ 819d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data(skb, n->data, n->len); 8201da177e4SLinus Torvalds 82125f484a6SHerbert Xu n->truesize += skb->data_len; 8221da177e4SLinus Torvalds n->data_len = skb->data_len; 8231da177e4SLinus Torvalds n->len = skb->len; 8241da177e4SLinus Torvalds 8251da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 8261da177e4SLinus Torvalds int i; 8271da177e4SLinus Torvalds 828a6686f2fSShirley Ma if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { 829a6686f2fSShirley Ma if (skb_copy_ubufs(skb, gfp_mask)) { 8301511022cSDan Carpenter kfree_skb(n); 8311511022cSDan Carpenter n = NULL; 832a6686f2fSShirley Ma goto out; 833a6686f2fSShirley Ma } 834a6686f2fSShirley Ma } 8351da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 8361da177e4SLinus Torvalds skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; 837ea2ab693SIan Campbell skb_frag_ref(skb, i); 8381da177e4SLinus Torvalds } 8391da177e4SLinus Torvalds skb_shinfo(n)->nr_frags = i; 8401da177e4SLinus Torvalds } 8411da177e4SLinus Torvalds 84221dc3301SDavid S. Miller if (skb_has_frag_list(skb)) { 8431da177e4SLinus Torvalds skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; 8441da177e4SLinus Torvalds skb_clone_fraglist(n); 8451da177e4SLinus Torvalds } 8461da177e4SLinus Torvalds 8471da177e4SLinus Torvalds copy_skb_header(n, skb); 8481da177e4SLinus Torvalds out: 8491da177e4SLinus Torvalds return n; 8501da177e4SLinus Torvalds } 851b4ac530fSDavid S. Miller EXPORT_SYMBOL(pskb_copy); 8521da177e4SLinus Torvalds 8531da177e4SLinus Torvalds /** 8541da177e4SLinus Torvalds * pskb_expand_head - reallocate header of &sk_buff 8551da177e4SLinus Torvalds * @skb: buffer to reallocate 8561da177e4SLinus Torvalds * @nhead: room to add at head 8571da177e4SLinus Torvalds * @ntail: room to add at tail 8581da177e4SLinus Torvalds * @gfp_mask: allocation priority 8591da177e4SLinus Torvalds * 8601da177e4SLinus Torvalds * Expands (or creates identical copy, if &nhead and &ntail are zero) 8611da177e4SLinus Torvalds * header of skb. &sk_buff itself is not changed. &sk_buff MUST have 8621da177e4SLinus Torvalds * reference count of 1. Returns zero in the case of success or error, 8631da177e4SLinus Torvalds * if expansion failed. In the last case, &sk_buff is not changed. 8641da177e4SLinus Torvalds * 8651da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 8661da177e4SLinus Torvalds * reloaded after call to this function. 8671da177e4SLinus Torvalds */ 8681da177e4SLinus Torvalds 86986a76cafSVictor Fusco int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, 870dd0fc66fSAl Viro gfp_t gfp_mask) 8711da177e4SLinus Torvalds { 8721da177e4SLinus Torvalds int i; 8731da177e4SLinus Torvalds u8 *data; 8746602cebbSEric Dumazet int size = nhead + (skb_end_pointer(skb) - skb->head) + ntail; 8751da177e4SLinus Torvalds long off; 8761fd63041SEric Dumazet bool fastpath; 8771da177e4SLinus Torvalds 8784edd87adSHerbert Xu BUG_ON(nhead < 0); 8794edd87adSHerbert Xu 8801da177e4SLinus Torvalds if (skb_shared(skb)) 8811da177e4SLinus Torvalds BUG(); 8821da177e4SLinus Torvalds 8831da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 8841da177e4SLinus Torvalds 885ca44ac38SChangli Gao /* Check if we can avoid taking references on fragments if we own 886ca44ac38SChangli Gao * the last reference on skb->head. (see skb_release_data()) 887ca44ac38SChangli Gao */ 888ca44ac38SChangli Gao if (!skb->cloned) 889ca44ac38SChangli Gao fastpath = true; 890ca44ac38SChangli Gao else { 891ca44ac38SChangli Gao int delta = skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1; 892ca44ac38SChangli Gao fastpath = atomic_read(&skb_shinfo(skb)->dataref) == delta; 893ca44ac38SChangli Gao } 894ca44ac38SChangli Gao 895ca44ac38SChangli Gao if (fastpath && 896ca44ac38SChangli Gao size + sizeof(struct skb_shared_info) <= ksize(skb->head)) { 897ca44ac38SChangli Gao memmove(skb->head + size, skb_shinfo(skb), 898ca44ac38SChangli Gao offsetof(struct skb_shared_info, 899ca44ac38SChangli Gao frags[skb_shinfo(skb)->nr_frags])); 900ca44ac38SChangli Gao memmove(skb->head + nhead, skb->head, 901ca44ac38SChangli Gao skb_tail_pointer(skb) - skb->head); 902ca44ac38SChangli Gao off = nhead; 903ca44ac38SChangli Gao goto adjust_others; 904ca44ac38SChangli Gao } 905ca44ac38SChangli Gao 9061da177e4SLinus Torvalds data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); 9071da177e4SLinus Torvalds if (!data) 9081da177e4SLinus Torvalds goto nodata; 9091da177e4SLinus Torvalds 9101da177e4SLinus Torvalds /* Copy only real data... and, alas, header. This should be 9116602cebbSEric Dumazet * optimized for the cases when header is void. 9126602cebbSEric Dumazet */ 9136602cebbSEric Dumazet memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head); 9146602cebbSEric Dumazet 9156602cebbSEric Dumazet memcpy((struct skb_shared_info *)(data + size), 9166602cebbSEric Dumazet skb_shinfo(skb), 917fed66381SEric Dumazet offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags])); 9181da177e4SLinus Torvalds 9191fd63041SEric Dumazet if (fastpath) { 9201fd63041SEric Dumazet kfree(skb->head); 9211fd63041SEric Dumazet } else { 922a6686f2fSShirley Ma /* copy this zero copy skb frags */ 923a6686f2fSShirley Ma if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { 924a6686f2fSShirley Ma if (skb_copy_ubufs(skb, gfp_mask)) 925a6686f2fSShirley Ma goto nofrags; 926a6686f2fSShirley Ma } 9271da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 928ea2ab693SIan Campbell skb_frag_ref(skb, i); 9291da177e4SLinus Torvalds 93021dc3301SDavid S. Miller if (skb_has_frag_list(skb)) 9311da177e4SLinus Torvalds skb_clone_fraglist(skb); 9321da177e4SLinus Torvalds 9331da177e4SLinus Torvalds skb_release_data(skb); 9341fd63041SEric Dumazet } 9351da177e4SLinus Torvalds off = (data + nhead) - skb->head; 9361da177e4SLinus Torvalds 9371da177e4SLinus Torvalds skb->head = data; 938ca44ac38SChangli Gao adjust_others: 9391da177e4SLinus Torvalds skb->data += off; 9404305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 9414305b541SArnaldo Carvalho de Melo skb->end = size; 94256eb8882SPatrick McHardy off = nhead; 9434305b541SArnaldo Carvalho de Melo #else 9444305b541SArnaldo Carvalho de Melo skb->end = skb->head + size; 94556eb8882SPatrick McHardy #endif 94627a884dcSArnaldo Carvalho de Melo /* {transport,network,mac}_header and tail are relative to skb->head */ 94727a884dcSArnaldo Carvalho de Melo skb->tail += off; 948b0e380b1SArnaldo Carvalho de Melo skb->transport_header += off; 949b0e380b1SArnaldo Carvalho de Melo skb->network_header += off; 950603a8bbeSStephen Hemminger if (skb_mac_header_was_set(skb)) 951b0e380b1SArnaldo Carvalho de Melo skb->mac_header += off; 95200c5a983SAndrea Shepard /* Only adjust this if it actually is csum_start rather than csum */ 95300c5a983SAndrea Shepard if (skb->ip_summed == CHECKSUM_PARTIAL) 954172a863fSHerbert Xu skb->csum_start += nhead; 9551da177e4SLinus Torvalds skb->cloned = 0; 956334a8132SPatrick McHardy skb->hdr_len = 0; 9571da177e4SLinus Torvalds skb->nohdr = 0; 9581da177e4SLinus Torvalds atomic_set(&skb_shinfo(skb)->dataref, 1); 9591da177e4SLinus Torvalds return 0; 9601da177e4SLinus Torvalds 961a6686f2fSShirley Ma nofrags: 962a6686f2fSShirley Ma kfree(data); 9631da177e4SLinus Torvalds nodata: 9641da177e4SLinus Torvalds return -ENOMEM; 9651da177e4SLinus Torvalds } 966b4ac530fSDavid S. Miller EXPORT_SYMBOL(pskb_expand_head); 9671da177e4SLinus Torvalds 9681da177e4SLinus Torvalds /* Make private copy of skb with writable head and some headroom */ 9691da177e4SLinus Torvalds 9701da177e4SLinus Torvalds struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) 9711da177e4SLinus Torvalds { 9721da177e4SLinus Torvalds struct sk_buff *skb2; 9731da177e4SLinus Torvalds int delta = headroom - skb_headroom(skb); 9741da177e4SLinus Torvalds 9751da177e4SLinus Torvalds if (delta <= 0) 9761da177e4SLinus Torvalds skb2 = pskb_copy(skb, GFP_ATOMIC); 9771da177e4SLinus Torvalds else { 9781da177e4SLinus Torvalds skb2 = skb_clone(skb, GFP_ATOMIC); 9791da177e4SLinus Torvalds if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, 9801da177e4SLinus Torvalds GFP_ATOMIC)) { 9811da177e4SLinus Torvalds kfree_skb(skb2); 9821da177e4SLinus Torvalds skb2 = NULL; 9831da177e4SLinus Torvalds } 9841da177e4SLinus Torvalds } 9851da177e4SLinus Torvalds return skb2; 9861da177e4SLinus Torvalds } 987b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_realloc_headroom); 9881da177e4SLinus Torvalds 9891da177e4SLinus Torvalds /** 9901da177e4SLinus Torvalds * skb_copy_expand - copy and expand sk_buff 9911da177e4SLinus Torvalds * @skb: buffer to copy 9921da177e4SLinus Torvalds * @newheadroom: new free bytes at head 9931da177e4SLinus Torvalds * @newtailroom: new free bytes at tail 9941da177e4SLinus Torvalds * @gfp_mask: allocation priority 9951da177e4SLinus Torvalds * 9961da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data and while doing so 9971da177e4SLinus Torvalds * allocate additional space. 9981da177e4SLinus Torvalds * 9991da177e4SLinus Torvalds * This is used when the caller wishes to modify the data and needs a 10001da177e4SLinus Torvalds * private copy of the data to alter as well as more space for new fields. 10011da177e4SLinus Torvalds * Returns %NULL on failure or the pointer to the buffer 10021da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 10031da177e4SLinus Torvalds * 10041da177e4SLinus Torvalds * You must pass %GFP_ATOMIC as the allocation priority if this function 10051da177e4SLinus Torvalds * is called from an interrupt. 10061da177e4SLinus Torvalds */ 10071da177e4SLinus Torvalds struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 100886a76cafSVictor Fusco int newheadroom, int newtailroom, 1009dd0fc66fSAl Viro gfp_t gfp_mask) 10101da177e4SLinus Torvalds { 10111da177e4SLinus Torvalds /* 10121da177e4SLinus Torvalds * Allocate the copy buffer 10131da177e4SLinus Torvalds */ 10141da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, 10151da177e4SLinus Torvalds gfp_mask); 1016efd1e8d5SPatrick McHardy int oldheadroom = skb_headroom(skb); 10171da177e4SLinus Torvalds int head_copy_len, head_copy_off; 101852886051SHerbert Xu int off; 10191da177e4SLinus Torvalds 10201da177e4SLinus Torvalds if (!n) 10211da177e4SLinus Torvalds return NULL; 10221da177e4SLinus Torvalds 10231da177e4SLinus Torvalds skb_reserve(n, newheadroom); 10241da177e4SLinus Torvalds 10251da177e4SLinus Torvalds /* Set the tail pointer and length */ 10261da177e4SLinus Torvalds skb_put(n, skb->len); 10271da177e4SLinus Torvalds 1028efd1e8d5SPatrick McHardy head_copy_len = oldheadroom; 10291da177e4SLinus Torvalds head_copy_off = 0; 10301da177e4SLinus Torvalds if (newheadroom <= head_copy_len) 10311da177e4SLinus Torvalds head_copy_len = newheadroom; 10321da177e4SLinus Torvalds else 10331da177e4SLinus Torvalds head_copy_off = newheadroom - head_copy_len; 10341da177e4SLinus Torvalds 10351da177e4SLinus Torvalds /* Copy the linear header and data. */ 10361da177e4SLinus Torvalds if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, 10371da177e4SLinus Torvalds skb->len + head_copy_len)) 10381da177e4SLinus Torvalds BUG(); 10391da177e4SLinus Torvalds 10401da177e4SLinus Torvalds copy_skb_header(n, skb); 10411da177e4SLinus Torvalds 1042efd1e8d5SPatrick McHardy off = newheadroom - oldheadroom; 1043be2b6e62SDavid S. Miller if (n->ip_summed == CHECKSUM_PARTIAL) 104452886051SHerbert Xu n->csum_start += off; 104552886051SHerbert Xu #ifdef NET_SKBUFF_DATA_USES_OFFSET 1046efd1e8d5SPatrick McHardy n->transport_header += off; 1047efd1e8d5SPatrick McHardy n->network_header += off; 1048603a8bbeSStephen Hemminger if (skb_mac_header_was_set(skb)) 1049efd1e8d5SPatrick McHardy n->mac_header += off; 105052886051SHerbert Xu #endif 1051efd1e8d5SPatrick McHardy 10521da177e4SLinus Torvalds return n; 10531da177e4SLinus Torvalds } 1054b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_expand); 10551da177e4SLinus Torvalds 10561da177e4SLinus Torvalds /** 10571da177e4SLinus Torvalds * skb_pad - zero pad the tail of an skb 10581da177e4SLinus Torvalds * @skb: buffer to pad 10591da177e4SLinus Torvalds * @pad: space to pad 10601da177e4SLinus Torvalds * 10611da177e4SLinus Torvalds * Ensure that a buffer is followed by a padding area that is zero 10621da177e4SLinus Torvalds * filled. Used by network drivers which may DMA or transfer data 10631da177e4SLinus Torvalds * beyond the buffer end onto the wire. 10641da177e4SLinus Torvalds * 10655b057c6bSHerbert Xu * May return error in out of memory cases. The skb is freed on error. 10661da177e4SLinus Torvalds */ 10671da177e4SLinus Torvalds 10685b057c6bSHerbert Xu int skb_pad(struct sk_buff *skb, int pad) 10691da177e4SLinus Torvalds { 10705b057c6bSHerbert Xu int err; 10715b057c6bSHerbert Xu int ntail; 10721da177e4SLinus Torvalds 10731da177e4SLinus Torvalds /* If the skbuff is non linear tailroom is always zero.. */ 10745b057c6bSHerbert Xu if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { 10751da177e4SLinus Torvalds memset(skb->data+skb->len, 0, pad); 10765b057c6bSHerbert Xu return 0; 10771da177e4SLinus Torvalds } 10781da177e4SLinus Torvalds 10794305b541SArnaldo Carvalho de Melo ntail = skb->data_len + pad - (skb->end - skb->tail); 10805b057c6bSHerbert Xu if (likely(skb_cloned(skb) || ntail > 0)) { 10815b057c6bSHerbert Xu err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); 10825b057c6bSHerbert Xu if (unlikely(err)) 10835b057c6bSHerbert Xu goto free_skb; 10845b057c6bSHerbert Xu } 10855b057c6bSHerbert Xu 10865b057c6bSHerbert Xu /* FIXME: The use of this function with non-linear skb's really needs 10875b057c6bSHerbert Xu * to be audited. 10885b057c6bSHerbert Xu */ 10895b057c6bSHerbert Xu err = skb_linearize(skb); 10905b057c6bSHerbert Xu if (unlikely(err)) 10915b057c6bSHerbert Xu goto free_skb; 10925b057c6bSHerbert Xu 10935b057c6bSHerbert Xu memset(skb->data + skb->len, 0, pad); 10945b057c6bSHerbert Xu return 0; 10955b057c6bSHerbert Xu 10965b057c6bSHerbert Xu free_skb: 10971da177e4SLinus Torvalds kfree_skb(skb); 10985b057c6bSHerbert Xu return err; 10991da177e4SLinus Torvalds } 1100b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_pad); 11011da177e4SLinus Torvalds 11020dde3e16SIlpo Järvinen /** 11030dde3e16SIlpo Järvinen * skb_put - add data to a buffer 11040dde3e16SIlpo Järvinen * @skb: buffer to use 11050dde3e16SIlpo Järvinen * @len: amount of data to add 11060dde3e16SIlpo Järvinen * 11070dde3e16SIlpo Järvinen * This function extends the used data area of the buffer. If this would 11080dde3e16SIlpo Järvinen * exceed the total buffer size the kernel will panic. A pointer to the 11090dde3e16SIlpo Järvinen * first byte of the extra data is returned. 11100dde3e16SIlpo Järvinen */ 11110dde3e16SIlpo Järvinen unsigned char *skb_put(struct sk_buff *skb, unsigned int len) 11120dde3e16SIlpo Järvinen { 11130dde3e16SIlpo Järvinen unsigned char *tmp = skb_tail_pointer(skb); 11140dde3e16SIlpo Järvinen SKB_LINEAR_ASSERT(skb); 11150dde3e16SIlpo Järvinen skb->tail += len; 11160dde3e16SIlpo Järvinen skb->len += len; 11170dde3e16SIlpo Järvinen if (unlikely(skb->tail > skb->end)) 11180dde3e16SIlpo Järvinen skb_over_panic(skb, len, __builtin_return_address(0)); 11190dde3e16SIlpo Järvinen return tmp; 11200dde3e16SIlpo Järvinen } 11210dde3e16SIlpo Järvinen EXPORT_SYMBOL(skb_put); 11220dde3e16SIlpo Järvinen 11236be8ac2fSIlpo Järvinen /** 1124c2aa270aSIlpo Järvinen * skb_push - add data to the start of a buffer 1125c2aa270aSIlpo Järvinen * @skb: buffer to use 1126c2aa270aSIlpo Järvinen * @len: amount of data to add 1127c2aa270aSIlpo Järvinen * 1128c2aa270aSIlpo Järvinen * This function extends the used data area of the buffer at the buffer 1129c2aa270aSIlpo Järvinen * start. If this would exceed the total buffer headroom the kernel will 1130c2aa270aSIlpo Järvinen * panic. A pointer to the first byte of the extra data is returned. 1131c2aa270aSIlpo Järvinen */ 1132c2aa270aSIlpo Järvinen unsigned char *skb_push(struct sk_buff *skb, unsigned int len) 1133c2aa270aSIlpo Järvinen { 1134c2aa270aSIlpo Järvinen skb->data -= len; 1135c2aa270aSIlpo Järvinen skb->len += len; 1136c2aa270aSIlpo Järvinen if (unlikely(skb->data<skb->head)) 1137c2aa270aSIlpo Järvinen skb_under_panic(skb, len, __builtin_return_address(0)); 1138c2aa270aSIlpo Järvinen return skb->data; 1139c2aa270aSIlpo Järvinen } 1140c2aa270aSIlpo Järvinen EXPORT_SYMBOL(skb_push); 1141c2aa270aSIlpo Järvinen 1142c2aa270aSIlpo Järvinen /** 11436be8ac2fSIlpo Järvinen * skb_pull - remove data from the start of a buffer 11446be8ac2fSIlpo Järvinen * @skb: buffer to use 11456be8ac2fSIlpo Järvinen * @len: amount of data to remove 11466be8ac2fSIlpo Järvinen * 11476be8ac2fSIlpo Järvinen * This function removes data from the start of a buffer, returning 11486be8ac2fSIlpo Järvinen * the memory to the headroom. A pointer to the next data in the buffer 11496be8ac2fSIlpo Järvinen * is returned. Once the data has been pulled future pushes will overwrite 11506be8ac2fSIlpo Järvinen * the old data. 11516be8ac2fSIlpo Järvinen */ 11526be8ac2fSIlpo Järvinen unsigned char *skb_pull(struct sk_buff *skb, unsigned int len) 11536be8ac2fSIlpo Järvinen { 115447d29646SDavid S. Miller return skb_pull_inline(skb, len); 11556be8ac2fSIlpo Järvinen } 11566be8ac2fSIlpo Järvinen EXPORT_SYMBOL(skb_pull); 11576be8ac2fSIlpo Järvinen 1158419ae74eSIlpo Järvinen /** 1159419ae74eSIlpo Järvinen * skb_trim - remove end from a buffer 1160419ae74eSIlpo Järvinen * @skb: buffer to alter 1161419ae74eSIlpo Järvinen * @len: new length 1162419ae74eSIlpo Järvinen * 1163419ae74eSIlpo Järvinen * Cut the length of a buffer down by removing data from the tail. If 1164419ae74eSIlpo Järvinen * the buffer is already under the length specified it is not modified. 1165419ae74eSIlpo Järvinen * The skb must be linear. 1166419ae74eSIlpo Järvinen */ 1167419ae74eSIlpo Järvinen void skb_trim(struct sk_buff *skb, unsigned int len) 1168419ae74eSIlpo Järvinen { 1169419ae74eSIlpo Järvinen if (skb->len > len) 1170419ae74eSIlpo Järvinen __skb_trim(skb, len); 1171419ae74eSIlpo Järvinen } 1172419ae74eSIlpo Järvinen EXPORT_SYMBOL(skb_trim); 1173419ae74eSIlpo Järvinen 11743cc0e873SHerbert Xu /* Trims skb to length len. It can change skb pointers. 11751da177e4SLinus Torvalds */ 11761da177e4SLinus Torvalds 11773cc0e873SHerbert Xu int ___pskb_trim(struct sk_buff *skb, unsigned int len) 11781da177e4SLinus Torvalds { 117927b437c8SHerbert Xu struct sk_buff **fragp; 118027b437c8SHerbert Xu struct sk_buff *frag; 11811da177e4SLinus Torvalds int offset = skb_headlen(skb); 11821da177e4SLinus Torvalds int nfrags = skb_shinfo(skb)->nr_frags; 11831da177e4SLinus Torvalds int i; 118427b437c8SHerbert Xu int err; 118527b437c8SHerbert Xu 118627b437c8SHerbert Xu if (skb_cloned(skb) && 118727b437c8SHerbert Xu unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) 118827b437c8SHerbert Xu return err; 11891da177e4SLinus Torvalds 1190f4d26fb3SHerbert Xu i = 0; 1191f4d26fb3SHerbert Xu if (offset >= len) 1192f4d26fb3SHerbert Xu goto drop_pages; 1193f4d26fb3SHerbert Xu 1194f4d26fb3SHerbert Xu for (; i < nfrags; i++) { 11959e903e08SEric Dumazet int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]); 119627b437c8SHerbert Xu 119727b437c8SHerbert Xu if (end < len) { 11981da177e4SLinus Torvalds offset = end; 119927b437c8SHerbert Xu continue; 12001da177e4SLinus Torvalds } 12011da177e4SLinus Torvalds 12029e903e08SEric Dumazet skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset); 120327b437c8SHerbert Xu 1204f4d26fb3SHerbert Xu drop_pages: 120527b437c8SHerbert Xu skb_shinfo(skb)->nr_frags = i; 120627b437c8SHerbert Xu 120727b437c8SHerbert Xu for (; i < nfrags; i++) 1208ea2ab693SIan Campbell skb_frag_unref(skb, i); 120927b437c8SHerbert Xu 121021dc3301SDavid S. Miller if (skb_has_frag_list(skb)) 121127b437c8SHerbert Xu skb_drop_fraglist(skb); 1212f4d26fb3SHerbert Xu goto done; 121327b437c8SHerbert Xu } 121427b437c8SHerbert Xu 121527b437c8SHerbert Xu for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); 121627b437c8SHerbert Xu fragp = &frag->next) { 121727b437c8SHerbert Xu int end = offset + frag->len; 121827b437c8SHerbert Xu 121927b437c8SHerbert Xu if (skb_shared(frag)) { 122027b437c8SHerbert Xu struct sk_buff *nfrag; 122127b437c8SHerbert Xu 122227b437c8SHerbert Xu nfrag = skb_clone(frag, GFP_ATOMIC); 122327b437c8SHerbert Xu if (unlikely(!nfrag)) 122427b437c8SHerbert Xu return -ENOMEM; 122527b437c8SHerbert Xu 122627b437c8SHerbert Xu nfrag->next = frag->next; 1227f4d26fb3SHerbert Xu kfree_skb(frag); 122827b437c8SHerbert Xu frag = nfrag; 122927b437c8SHerbert Xu *fragp = frag; 123027b437c8SHerbert Xu } 123127b437c8SHerbert Xu 123227b437c8SHerbert Xu if (end < len) { 123327b437c8SHerbert Xu offset = end; 123427b437c8SHerbert Xu continue; 123527b437c8SHerbert Xu } 123627b437c8SHerbert Xu 123727b437c8SHerbert Xu if (end > len && 123827b437c8SHerbert Xu unlikely((err = pskb_trim(frag, len - offset)))) 123927b437c8SHerbert Xu return err; 124027b437c8SHerbert Xu 124127b437c8SHerbert Xu if (frag->next) 124227b437c8SHerbert Xu skb_drop_list(&frag->next); 124327b437c8SHerbert Xu break; 124427b437c8SHerbert Xu } 124527b437c8SHerbert Xu 1246f4d26fb3SHerbert Xu done: 124727b437c8SHerbert Xu if (len > skb_headlen(skb)) { 12481da177e4SLinus Torvalds skb->data_len -= skb->len - len; 12491da177e4SLinus Torvalds skb->len = len; 12501da177e4SLinus Torvalds } else { 12511da177e4SLinus Torvalds skb->len = len; 12521da177e4SLinus Torvalds skb->data_len = 0; 125327a884dcSArnaldo Carvalho de Melo skb_set_tail_pointer(skb, len); 12541da177e4SLinus Torvalds } 12551da177e4SLinus Torvalds 12561da177e4SLinus Torvalds return 0; 12571da177e4SLinus Torvalds } 1258b4ac530fSDavid S. Miller EXPORT_SYMBOL(___pskb_trim); 12591da177e4SLinus Torvalds 12601da177e4SLinus Torvalds /** 12611da177e4SLinus Torvalds * __pskb_pull_tail - advance tail of skb header 12621da177e4SLinus Torvalds * @skb: buffer to reallocate 12631da177e4SLinus Torvalds * @delta: number of bytes to advance tail 12641da177e4SLinus Torvalds * 12651da177e4SLinus Torvalds * The function makes a sense only on a fragmented &sk_buff, 12661da177e4SLinus Torvalds * it expands header moving its tail forward and copying necessary 12671da177e4SLinus Torvalds * data from fragmented part. 12681da177e4SLinus Torvalds * 12691da177e4SLinus Torvalds * &sk_buff MUST have reference count of 1. 12701da177e4SLinus Torvalds * 12711da177e4SLinus Torvalds * Returns %NULL (and &sk_buff does not change) if pull failed 12721da177e4SLinus Torvalds * or value of new tail of skb in the case of success. 12731da177e4SLinus Torvalds * 12741da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 12751da177e4SLinus Torvalds * reloaded after call to this function. 12761da177e4SLinus Torvalds */ 12771da177e4SLinus Torvalds 12781da177e4SLinus Torvalds /* Moves tail of skb head forward, copying data from fragmented part, 12791da177e4SLinus Torvalds * when it is necessary. 12801da177e4SLinus Torvalds * 1. It may fail due to malloc failure. 12811da177e4SLinus Torvalds * 2. It may change skb pointers. 12821da177e4SLinus Torvalds * 12831da177e4SLinus Torvalds * It is pretty complicated. Luckily, it is called only in exceptional cases. 12841da177e4SLinus Torvalds */ 12851da177e4SLinus Torvalds unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) 12861da177e4SLinus Torvalds { 12871da177e4SLinus Torvalds /* If skb has not enough free space at tail, get new one 12881da177e4SLinus Torvalds * plus 128 bytes for future expansions. If we have enough 12891da177e4SLinus Torvalds * room at tail, reallocate without expansion only if skb is cloned. 12901da177e4SLinus Torvalds */ 12914305b541SArnaldo Carvalho de Melo int i, k, eat = (skb->tail + delta) - skb->end; 12921da177e4SLinus Torvalds 12931da177e4SLinus Torvalds if (eat > 0 || skb_cloned(skb)) { 12941da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, 12951da177e4SLinus Torvalds GFP_ATOMIC)) 12961da177e4SLinus Torvalds return NULL; 12971da177e4SLinus Torvalds } 12981da177e4SLinus Torvalds 129927a884dcSArnaldo Carvalho de Melo if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta)) 13001da177e4SLinus Torvalds BUG(); 13011da177e4SLinus Torvalds 13021da177e4SLinus Torvalds /* Optimization: no fragments, no reasons to preestimate 13031da177e4SLinus Torvalds * size of pulled pages. Superb. 13041da177e4SLinus Torvalds */ 130521dc3301SDavid S. Miller if (!skb_has_frag_list(skb)) 13061da177e4SLinus Torvalds goto pull_pages; 13071da177e4SLinus Torvalds 13081da177e4SLinus Torvalds /* Estimate size of pulled pages. */ 13091da177e4SLinus Torvalds eat = delta; 13101da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 13119e903e08SEric Dumazet int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); 13129e903e08SEric Dumazet 13139e903e08SEric Dumazet if (size >= eat) 13141da177e4SLinus Torvalds goto pull_pages; 13159e903e08SEric Dumazet eat -= size; 13161da177e4SLinus Torvalds } 13171da177e4SLinus Torvalds 13181da177e4SLinus Torvalds /* If we need update frag list, we are in troubles. 13191da177e4SLinus Torvalds * Certainly, it possible to add an offset to skb data, 13201da177e4SLinus Torvalds * but taking into account that pulling is expected to 13211da177e4SLinus Torvalds * be very rare operation, it is worth to fight against 13221da177e4SLinus Torvalds * further bloating skb head and crucify ourselves here instead. 13231da177e4SLinus Torvalds * Pure masohism, indeed. 8)8) 13241da177e4SLinus Torvalds */ 13251da177e4SLinus Torvalds if (eat) { 13261da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 13271da177e4SLinus Torvalds struct sk_buff *clone = NULL; 13281da177e4SLinus Torvalds struct sk_buff *insp = NULL; 13291da177e4SLinus Torvalds 13301da177e4SLinus Torvalds do { 133109a62660SKris Katterjohn BUG_ON(!list); 13321da177e4SLinus Torvalds 13331da177e4SLinus Torvalds if (list->len <= eat) { 13341da177e4SLinus Torvalds /* Eaten as whole. */ 13351da177e4SLinus Torvalds eat -= list->len; 13361da177e4SLinus Torvalds list = list->next; 13371da177e4SLinus Torvalds insp = list; 13381da177e4SLinus Torvalds } else { 13391da177e4SLinus Torvalds /* Eaten partially. */ 13401da177e4SLinus Torvalds 13411da177e4SLinus Torvalds if (skb_shared(list)) { 13421da177e4SLinus Torvalds /* Sucks! We need to fork list. :-( */ 13431da177e4SLinus Torvalds clone = skb_clone(list, GFP_ATOMIC); 13441da177e4SLinus Torvalds if (!clone) 13451da177e4SLinus Torvalds return NULL; 13461da177e4SLinus Torvalds insp = list->next; 13471da177e4SLinus Torvalds list = clone; 13481da177e4SLinus Torvalds } else { 13491da177e4SLinus Torvalds /* This may be pulled without 13501da177e4SLinus Torvalds * problems. */ 13511da177e4SLinus Torvalds insp = list; 13521da177e4SLinus Torvalds } 13531da177e4SLinus Torvalds if (!pskb_pull(list, eat)) { 13541da177e4SLinus Torvalds kfree_skb(clone); 13551da177e4SLinus Torvalds return NULL; 13561da177e4SLinus Torvalds } 13571da177e4SLinus Torvalds break; 13581da177e4SLinus Torvalds } 13591da177e4SLinus Torvalds } while (eat); 13601da177e4SLinus Torvalds 13611da177e4SLinus Torvalds /* Free pulled out fragments. */ 13621da177e4SLinus Torvalds while ((list = skb_shinfo(skb)->frag_list) != insp) { 13631da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = list->next; 13641da177e4SLinus Torvalds kfree_skb(list); 13651da177e4SLinus Torvalds } 13661da177e4SLinus Torvalds /* And insert new clone at head. */ 13671da177e4SLinus Torvalds if (clone) { 13681da177e4SLinus Torvalds clone->next = list; 13691da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = clone; 13701da177e4SLinus Torvalds } 13711da177e4SLinus Torvalds } 13721da177e4SLinus Torvalds /* Success! Now we may commit changes to skb data. */ 13731da177e4SLinus Torvalds 13741da177e4SLinus Torvalds pull_pages: 13751da177e4SLinus Torvalds eat = delta; 13761da177e4SLinus Torvalds k = 0; 13771da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 13789e903e08SEric Dumazet int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); 13799e903e08SEric Dumazet 13809e903e08SEric Dumazet if (size <= eat) { 1381ea2ab693SIan Campbell skb_frag_unref(skb, i); 13829e903e08SEric Dumazet eat -= size; 13831da177e4SLinus Torvalds } else { 13841da177e4SLinus Torvalds skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; 13851da177e4SLinus Torvalds if (eat) { 13861da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].page_offset += eat; 13879e903e08SEric Dumazet skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat); 13881da177e4SLinus Torvalds eat = 0; 13891da177e4SLinus Torvalds } 13901da177e4SLinus Torvalds k++; 13911da177e4SLinus Torvalds } 13921da177e4SLinus Torvalds } 13931da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = k; 13941da177e4SLinus Torvalds 13951da177e4SLinus Torvalds skb->tail += delta; 13961da177e4SLinus Torvalds skb->data_len -= delta; 13971da177e4SLinus Torvalds 139827a884dcSArnaldo Carvalho de Melo return skb_tail_pointer(skb); 13991da177e4SLinus Torvalds } 1400b4ac530fSDavid S. Miller EXPORT_SYMBOL(__pskb_pull_tail); 14011da177e4SLinus Torvalds 140222019b17SEric Dumazet /** 140322019b17SEric Dumazet * skb_copy_bits - copy bits from skb to kernel buffer 140422019b17SEric Dumazet * @skb: source skb 140522019b17SEric Dumazet * @offset: offset in source 140622019b17SEric Dumazet * @to: destination buffer 140722019b17SEric Dumazet * @len: number of bytes to copy 140822019b17SEric Dumazet * 140922019b17SEric Dumazet * Copy the specified number of bytes from the source skb to the 141022019b17SEric Dumazet * destination buffer. 141122019b17SEric Dumazet * 141222019b17SEric Dumazet * CAUTION ! : 141322019b17SEric Dumazet * If its prototype is ever changed, 141422019b17SEric Dumazet * check arch/{*}/net/{*}.S files, 141522019b17SEric Dumazet * since it is called from BPF assembly code. 141622019b17SEric Dumazet */ 14171da177e4SLinus Torvalds int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) 14181da177e4SLinus Torvalds { 14191a028e50SDavid S. Miller int start = skb_headlen(skb); 1420fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 1421fbb398a8SDavid S. Miller int i, copy; 14221da177e4SLinus Torvalds 14231da177e4SLinus Torvalds if (offset > (int)skb->len - len) 14241da177e4SLinus Torvalds goto fault; 14251da177e4SLinus Torvalds 14261da177e4SLinus Torvalds /* Copy header. */ 14271a028e50SDavid S. Miller if ((copy = start - offset) > 0) { 14281da177e4SLinus Torvalds if (copy > len) 14291da177e4SLinus Torvalds copy = len; 1430d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, offset, to, copy); 14311da177e4SLinus Torvalds if ((len -= copy) == 0) 14321da177e4SLinus Torvalds return 0; 14331da177e4SLinus Torvalds offset += copy; 14341da177e4SLinus Torvalds to += copy; 14351da177e4SLinus Torvalds } 14361da177e4SLinus Torvalds 14371da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 14381a028e50SDavid S. Miller int end; 14391da177e4SLinus Torvalds 1440547b792cSIlpo Järvinen WARN_ON(start > offset + len); 14411a028e50SDavid S. Miller 14429e903e08SEric Dumazet end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]); 14431da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 14441da177e4SLinus Torvalds u8 *vaddr; 14451da177e4SLinus Torvalds 14461da177e4SLinus Torvalds if (copy > len) 14471da177e4SLinus Torvalds copy = len; 14481da177e4SLinus Torvalds 14491da177e4SLinus Torvalds vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); 14501da177e4SLinus Torvalds memcpy(to, 14511a028e50SDavid S. Miller vaddr + skb_shinfo(skb)->frags[i].page_offset+ 14521a028e50SDavid S. Miller offset - start, copy); 14531da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 14541da177e4SLinus Torvalds 14551da177e4SLinus Torvalds if ((len -= copy) == 0) 14561da177e4SLinus Torvalds return 0; 14571da177e4SLinus Torvalds offset += copy; 14581da177e4SLinus Torvalds to += copy; 14591da177e4SLinus Torvalds } 14601a028e50SDavid S. Miller start = end; 14611da177e4SLinus Torvalds } 14621da177e4SLinus Torvalds 1463fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 14641a028e50SDavid S. Miller int end; 14651da177e4SLinus Torvalds 1466547b792cSIlpo Järvinen WARN_ON(start > offset + len); 14671a028e50SDavid S. Miller 1468fbb398a8SDavid S. Miller end = start + frag_iter->len; 14691da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 14701da177e4SLinus Torvalds if (copy > len) 14711da177e4SLinus Torvalds copy = len; 1472fbb398a8SDavid S. Miller if (skb_copy_bits(frag_iter, offset - start, to, copy)) 14731da177e4SLinus Torvalds goto fault; 14741da177e4SLinus Torvalds if ((len -= copy) == 0) 14751da177e4SLinus Torvalds return 0; 14761da177e4SLinus Torvalds offset += copy; 14771da177e4SLinus Torvalds to += copy; 14781da177e4SLinus Torvalds } 14791a028e50SDavid S. Miller start = end; 14801da177e4SLinus Torvalds } 1481a6686f2fSShirley Ma 14821da177e4SLinus Torvalds if (!len) 14831da177e4SLinus Torvalds return 0; 14841da177e4SLinus Torvalds 14851da177e4SLinus Torvalds fault: 14861da177e4SLinus Torvalds return -EFAULT; 14871da177e4SLinus Torvalds } 1488b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_bits); 14891da177e4SLinus Torvalds 14909c55e01cSJens Axboe /* 14919c55e01cSJens Axboe * Callback from splice_to_pipe(), if we need to release some pages 14929c55e01cSJens Axboe * at the end of the spd in case we error'ed out in filling the pipe. 14939c55e01cSJens Axboe */ 14949c55e01cSJens Axboe static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) 14959c55e01cSJens Axboe { 14968b9d3728SJarek Poplawski put_page(spd->pages[i]); 14978b9d3728SJarek Poplawski } 14989c55e01cSJens Axboe 14994fb66994SJarek Poplawski static inline struct page *linear_to_page(struct page *page, unsigned int *len, 15004fb66994SJarek Poplawski unsigned int *offset, 15017a67e56fSJarek Poplawski struct sk_buff *skb, struct sock *sk) 15028b9d3728SJarek Poplawski { 15034fb66994SJarek Poplawski struct page *p = sk->sk_sndmsg_page; 15044fb66994SJarek Poplawski unsigned int off; 15058b9d3728SJarek Poplawski 15064fb66994SJarek Poplawski if (!p) { 15074fb66994SJarek Poplawski new_page: 15084fb66994SJarek Poplawski p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0); 15098b9d3728SJarek Poplawski if (!p) 15108b9d3728SJarek Poplawski return NULL; 15114fb66994SJarek Poplawski 15124fb66994SJarek Poplawski off = sk->sk_sndmsg_off = 0; 15134fb66994SJarek Poplawski /* hold one ref to this page until it's full */ 15144fb66994SJarek Poplawski } else { 15154fb66994SJarek Poplawski unsigned int mlen; 15164fb66994SJarek Poplawski 15174fb66994SJarek Poplawski off = sk->sk_sndmsg_off; 15184fb66994SJarek Poplawski mlen = PAGE_SIZE - off; 15194fb66994SJarek Poplawski if (mlen < 64 && mlen < *len) { 15204fb66994SJarek Poplawski put_page(p); 15214fb66994SJarek Poplawski goto new_page; 15224fb66994SJarek Poplawski } 15234fb66994SJarek Poplawski 15244fb66994SJarek Poplawski *len = min_t(unsigned int, *len, mlen); 15254fb66994SJarek Poplawski } 15264fb66994SJarek Poplawski 15274fb66994SJarek Poplawski memcpy(page_address(p) + off, page_address(page) + *offset, *len); 15284fb66994SJarek Poplawski sk->sk_sndmsg_off += *len; 15294fb66994SJarek Poplawski *offset = off; 15304fb66994SJarek Poplawski get_page(p); 15318b9d3728SJarek Poplawski 15328b9d3728SJarek Poplawski return p; 15339c55e01cSJens Axboe } 15349c55e01cSJens Axboe 15359c55e01cSJens Axboe /* 15369c55e01cSJens Axboe * Fill page/offset/length into spd, if it can hold more pages. 15379c55e01cSJens Axboe */ 153835f3d14dSJens Axboe static inline int spd_fill_page(struct splice_pipe_desc *spd, 153935f3d14dSJens Axboe struct pipe_inode_info *pipe, struct page *page, 15404fb66994SJarek Poplawski unsigned int *len, unsigned int offset, 15417a67e56fSJarek Poplawski struct sk_buff *skb, int linear, 15427a67e56fSJarek Poplawski struct sock *sk) 15439c55e01cSJens Axboe { 154435f3d14dSJens Axboe if (unlikely(spd->nr_pages == pipe->buffers)) 15459c55e01cSJens Axboe return 1; 15469c55e01cSJens Axboe 15478b9d3728SJarek Poplawski if (linear) { 15487a67e56fSJarek Poplawski page = linear_to_page(page, len, &offset, skb, sk); 15498b9d3728SJarek Poplawski if (!page) 15508b9d3728SJarek Poplawski return 1; 15518b9d3728SJarek Poplawski } else 15528b9d3728SJarek Poplawski get_page(page); 15538b9d3728SJarek Poplawski 15549c55e01cSJens Axboe spd->pages[spd->nr_pages] = page; 15554fb66994SJarek Poplawski spd->partial[spd->nr_pages].len = *len; 15569c55e01cSJens Axboe spd->partial[spd->nr_pages].offset = offset; 15579c55e01cSJens Axboe spd->nr_pages++; 15588b9d3728SJarek Poplawski 15599c55e01cSJens Axboe return 0; 15609c55e01cSJens Axboe } 15619c55e01cSJens Axboe 15622870c43dSOctavian Purdila static inline void __segment_seek(struct page **page, unsigned int *poff, 15632870c43dSOctavian Purdila unsigned int *plen, unsigned int off) 15642870c43dSOctavian Purdila { 1565ce3dd395SJarek Poplawski unsigned long n; 1566ce3dd395SJarek Poplawski 15672870c43dSOctavian Purdila *poff += off; 1568ce3dd395SJarek Poplawski n = *poff / PAGE_SIZE; 1569ce3dd395SJarek Poplawski if (n) 1570ce3dd395SJarek Poplawski *page = nth_page(*page, n); 1571ce3dd395SJarek Poplawski 15722870c43dSOctavian Purdila *poff = *poff % PAGE_SIZE; 15732870c43dSOctavian Purdila *plen -= off; 15742870c43dSOctavian Purdila } 15752870c43dSOctavian Purdila 15762870c43dSOctavian Purdila static inline int __splice_segment(struct page *page, unsigned int poff, 15772870c43dSOctavian Purdila unsigned int plen, unsigned int *off, 15782870c43dSOctavian Purdila unsigned int *len, struct sk_buff *skb, 15797a67e56fSJarek Poplawski struct splice_pipe_desc *spd, int linear, 158035f3d14dSJens Axboe struct sock *sk, 158135f3d14dSJens Axboe struct pipe_inode_info *pipe) 15829c55e01cSJens Axboe { 15832870c43dSOctavian Purdila if (!*len) 15842870c43dSOctavian Purdila return 1; 15859c55e01cSJens Axboe 15862870c43dSOctavian Purdila /* skip this segment if already processed */ 15872870c43dSOctavian Purdila if (*off >= plen) { 15882870c43dSOctavian Purdila *off -= plen; 15892870c43dSOctavian Purdila return 0; 15902870c43dSOctavian Purdila } 15912870c43dSOctavian Purdila 15922870c43dSOctavian Purdila /* ignore any bits we already processed */ 15932870c43dSOctavian Purdila if (*off) { 15942870c43dSOctavian Purdila __segment_seek(&page, &poff, &plen, *off); 15952870c43dSOctavian Purdila *off = 0; 15962870c43dSOctavian Purdila } 15972870c43dSOctavian Purdila 15982870c43dSOctavian Purdila do { 15992870c43dSOctavian Purdila unsigned int flen = min(*len, plen); 16002870c43dSOctavian Purdila 16012870c43dSOctavian Purdila /* the linear region may spread across several pages */ 16022870c43dSOctavian Purdila flen = min_t(unsigned int, flen, PAGE_SIZE - poff); 16032870c43dSOctavian Purdila 160435f3d14dSJens Axboe if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk)) 16052870c43dSOctavian Purdila return 1; 16062870c43dSOctavian Purdila 16072870c43dSOctavian Purdila __segment_seek(&page, &poff, &plen, flen); 16082870c43dSOctavian Purdila *len -= flen; 16092870c43dSOctavian Purdila 16102870c43dSOctavian Purdila } while (*len && plen); 16112870c43dSOctavian Purdila 16122870c43dSOctavian Purdila return 0; 1613db43a282SOctavian Purdila } 16149c55e01cSJens Axboe 16159c55e01cSJens Axboe /* 16162870c43dSOctavian Purdila * Map linear and fragment data from the skb to spd. It reports failure if the 16172870c43dSOctavian Purdila * pipe is full or if we already spliced the requested length. 16189c55e01cSJens Axboe */ 161935f3d14dSJens Axboe static int __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, 162035f3d14dSJens Axboe unsigned int *offset, unsigned int *len, 162135f3d14dSJens Axboe struct splice_pipe_desc *spd, struct sock *sk) 16222870c43dSOctavian Purdila { 16232870c43dSOctavian Purdila int seg; 16249c55e01cSJens Axboe 16259c55e01cSJens Axboe /* 16262870c43dSOctavian Purdila * map the linear part 16279c55e01cSJens Axboe */ 16282870c43dSOctavian Purdila if (__splice_segment(virt_to_page(skb->data), 16292870c43dSOctavian Purdila (unsigned long) skb->data & (PAGE_SIZE - 1), 16302870c43dSOctavian Purdila skb_headlen(skb), 163135f3d14dSJens Axboe offset, len, skb, spd, 1, sk, pipe)) 16322870c43dSOctavian Purdila return 1; 16339c55e01cSJens Axboe 16349c55e01cSJens Axboe /* 16359c55e01cSJens Axboe * then map the fragments 16369c55e01cSJens Axboe */ 16379c55e01cSJens Axboe for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { 16389c55e01cSJens Axboe const skb_frag_t *f = &skb_shinfo(skb)->frags[seg]; 16399c55e01cSJens Axboe 1640ea2ab693SIan Campbell if (__splice_segment(skb_frag_page(f), 16419e903e08SEric Dumazet f->page_offset, skb_frag_size(f), 164235f3d14dSJens Axboe offset, len, skb, spd, 0, sk, pipe)) 16432870c43dSOctavian Purdila return 1; 16449c55e01cSJens Axboe } 16459c55e01cSJens Axboe 16469c55e01cSJens Axboe return 0; 16479c55e01cSJens Axboe } 16489c55e01cSJens Axboe 16499c55e01cSJens Axboe /* 16509c55e01cSJens Axboe * Map data from the skb to a pipe. Should handle both the linear part, 16519c55e01cSJens Axboe * the fragments, and the frag list. It does NOT handle frag lists within 16529c55e01cSJens Axboe * the frag list, if such a thing exists. We'd probably need to recurse to 16539c55e01cSJens Axboe * handle that cleanly. 16549c55e01cSJens Axboe */ 16558b9d3728SJarek Poplawski int skb_splice_bits(struct sk_buff *skb, unsigned int offset, 16569c55e01cSJens Axboe struct pipe_inode_info *pipe, unsigned int tlen, 16579c55e01cSJens Axboe unsigned int flags) 16589c55e01cSJens Axboe { 165935f3d14dSJens Axboe struct partial_page partial[PIPE_DEF_BUFFERS]; 166035f3d14dSJens Axboe struct page *pages[PIPE_DEF_BUFFERS]; 16619c55e01cSJens Axboe struct splice_pipe_desc spd = { 16629c55e01cSJens Axboe .pages = pages, 16639c55e01cSJens Axboe .partial = partial, 16649c55e01cSJens Axboe .flags = flags, 16659c55e01cSJens Axboe .ops = &sock_pipe_buf_ops, 16669c55e01cSJens Axboe .spd_release = sock_spd_release, 16679c55e01cSJens Axboe }; 1668fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 16697a67e56fSJarek Poplawski struct sock *sk = skb->sk; 167035f3d14dSJens Axboe int ret = 0; 167135f3d14dSJens Axboe 167235f3d14dSJens Axboe if (splice_grow_spd(pipe, &spd)) 167335f3d14dSJens Axboe return -ENOMEM; 16749c55e01cSJens Axboe 16759c55e01cSJens Axboe /* 16769c55e01cSJens Axboe * __skb_splice_bits() only fails if the output has no room left, 16779c55e01cSJens Axboe * so no point in going over the frag_list for the error case. 16789c55e01cSJens Axboe */ 167935f3d14dSJens Axboe if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk)) 16809c55e01cSJens Axboe goto done; 16819c55e01cSJens Axboe else if (!tlen) 16829c55e01cSJens Axboe goto done; 16839c55e01cSJens Axboe 16849c55e01cSJens Axboe /* 16859c55e01cSJens Axboe * now see if we have a frag_list to map 16869c55e01cSJens Axboe */ 1687fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 1688fbb398a8SDavid S. Miller if (!tlen) 16899c55e01cSJens Axboe break; 169035f3d14dSJens Axboe if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk)) 1691fbb398a8SDavid S. Miller break; 16929c55e01cSJens Axboe } 16939c55e01cSJens Axboe 16949c55e01cSJens Axboe done: 16959c55e01cSJens Axboe if (spd.nr_pages) { 16969c55e01cSJens Axboe /* 16979c55e01cSJens Axboe * Drop the socket lock, otherwise we have reverse 16989c55e01cSJens Axboe * locking dependencies between sk_lock and i_mutex 16999c55e01cSJens Axboe * here as compared to sendfile(). We enter here 17009c55e01cSJens Axboe * with the socket lock held, and splice_to_pipe() will 17019c55e01cSJens Axboe * grab the pipe inode lock. For sendfile() emulation, 17029c55e01cSJens Axboe * we call into ->sendpage() with the i_mutex lock held 17039c55e01cSJens Axboe * and networking will grab the socket lock. 17049c55e01cSJens Axboe */ 1705293ad604SOctavian Purdila release_sock(sk); 17069c55e01cSJens Axboe ret = splice_to_pipe(pipe, &spd); 1707293ad604SOctavian Purdila lock_sock(sk); 17089c55e01cSJens Axboe } 17099c55e01cSJens Axboe 171035f3d14dSJens Axboe splice_shrink_spd(pipe, &spd); 171135f3d14dSJens Axboe return ret; 17129c55e01cSJens Axboe } 17139c55e01cSJens Axboe 1714357b40a1SHerbert Xu /** 1715357b40a1SHerbert Xu * skb_store_bits - store bits from kernel buffer to skb 1716357b40a1SHerbert Xu * @skb: destination buffer 1717357b40a1SHerbert Xu * @offset: offset in destination 1718357b40a1SHerbert Xu * @from: source buffer 1719357b40a1SHerbert Xu * @len: number of bytes to copy 1720357b40a1SHerbert Xu * 1721357b40a1SHerbert Xu * Copy the specified number of bytes from the source buffer to the 1722357b40a1SHerbert Xu * destination skb. This function handles all the messy bits of 1723357b40a1SHerbert Xu * traversing fragment lists and such. 1724357b40a1SHerbert Xu */ 1725357b40a1SHerbert Xu 17260c6fcc8aSStephen Hemminger int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len) 1727357b40a1SHerbert Xu { 17281a028e50SDavid S. Miller int start = skb_headlen(skb); 1729fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 1730fbb398a8SDavid S. Miller int i, copy; 1731357b40a1SHerbert Xu 1732357b40a1SHerbert Xu if (offset > (int)skb->len - len) 1733357b40a1SHerbert Xu goto fault; 1734357b40a1SHerbert Xu 17351a028e50SDavid S. Miller if ((copy = start - offset) > 0) { 1736357b40a1SHerbert Xu if (copy > len) 1737357b40a1SHerbert Xu copy = len; 173827d7ff46SArnaldo Carvalho de Melo skb_copy_to_linear_data_offset(skb, offset, from, copy); 1739357b40a1SHerbert Xu if ((len -= copy) == 0) 1740357b40a1SHerbert Xu return 0; 1741357b40a1SHerbert Xu offset += copy; 1742357b40a1SHerbert Xu from += copy; 1743357b40a1SHerbert Xu } 1744357b40a1SHerbert Xu 1745357b40a1SHerbert Xu for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 1746357b40a1SHerbert Xu skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 17471a028e50SDavid S. Miller int end; 1748357b40a1SHerbert Xu 1749547b792cSIlpo Järvinen WARN_ON(start > offset + len); 17501a028e50SDavid S. Miller 17519e903e08SEric Dumazet end = start + skb_frag_size(frag); 1752357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1753357b40a1SHerbert Xu u8 *vaddr; 1754357b40a1SHerbert Xu 1755357b40a1SHerbert Xu if (copy > len) 1756357b40a1SHerbert Xu copy = len; 1757357b40a1SHerbert Xu 1758357b40a1SHerbert Xu vaddr = kmap_skb_frag(frag); 17591a028e50SDavid S. Miller memcpy(vaddr + frag->page_offset + offset - start, 17601a028e50SDavid S. Miller from, copy); 1761357b40a1SHerbert Xu kunmap_skb_frag(vaddr); 1762357b40a1SHerbert Xu 1763357b40a1SHerbert Xu if ((len -= copy) == 0) 1764357b40a1SHerbert Xu return 0; 1765357b40a1SHerbert Xu offset += copy; 1766357b40a1SHerbert Xu from += copy; 1767357b40a1SHerbert Xu } 17681a028e50SDavid S. Miller start = end; 1769357b40a1SHerbert Xu } 1770357b40a1SHerbert Xu 1771fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 17721a028e50SDavid S. Miller int end; 1773357b40a1SHerbert Xu 1774547b792cSIlpo Järvinen WARN_ON(start > offset + len); 17751a028e50SDavid S. Miller 1776fbb398a8SDavid S. Miller end = start + frag_iter->len; 1777357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1778357b40a1SHerbert Xu if (copy > len) 1779357b40a1SHerbert Xu copy = len; 1780fbb398a8SDavid S. Miller if (skb_store_bits(frag_iter, offset - start, 17811a028e50SDavid S. Miller from, copy)) 1782357b40a1SHerbert Xu goto fault; 1783357b40a1SHerbert Xu if ((len -= copy) == 0) 1784357b40a1SHerbert Xu return 0; 1785357b40a1SHerbert Xu offset += copy; 1786357b40a1SHerbert Xu from += copy; 1787357b40a1SHerbert Xu } 17881a028e50SDavid S. Miller start = end; 1789357b40a1SHerbert Xu } 1790357b40a1SHerbert Xu if (!len) 1791357b40a1SHerbert Xu return 0; 1792357b40a1SHerbert Xu 1793357b40a1SHerbert Xu fault: 1794357b40a1SHerbert Xu return -EFAULT; 1795357b40a1SHerbert Xu } 1796357b40a1SHerbert Xu EXPORT_SYMBOL(skb_store_bits); 1797357b40a1SHerbert Xu 17981da177e4SLinus Torvalds /* Checksum skb data. */ 17991da177e4SLinus Torvalds 18002bbbc868SAl Viro __wsum skb_checksum(const struct sk_buff *skb, int offset, 18012bbbc868SAl Viro int len, __wsum csum) 18021da177e4SLinus Torvalds { 18031a028e50SDavid S. Miller int start = skb_headlen(skb); 18041a028e50SDavid S. Miller int i, copy = start - offset; 1805fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 18061da177e4SLinus Torvalds int pos = 0; 18071da177e4SLinus Torvalds 18081da177e4SLinus Torvalds /* Checksum header. */ 18091da177e4SLinus Torvalds if (copy > 0) { 18101da177e4SLinus Torvalds if (copy > len) 18111da177e4SLinus Torvalds copy = len; 18121da177e4SLinus Torvalds csum = csum_partial(skb->data + offset, copy, csum); 18131da177e4SLinus Torvalds if ((len -= copy) == 0) 18141da177e4SLinus Torvalds return csum; 18151da177e4SLinus Torvalds offset += copy; 18161da177e4SLinus Torvalds pos = copy; 18171da177e4SLinus Torvalds } 18181da177e4SLinus Torvalds 18191da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 18201a028e50SDavid S. Miller int end; 18211da177e4SLinus Torvalds 1822547b792cSIlpo Järvinen WARN_ON(start > offset + len); 18231a028e50SDavid S. Miller 18249e903e08SEric Dumazet end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]); 18251da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 182644bb9363SAl Viro __wsum csum2; 18271da177e4SLinus Torvalds u8 *vaddr; 18281da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 18291da177e4SLinus Torvalds 18301da177e4SLinus Torvalds if (copy > len) 18311da177e4SLinus Torvalds copy = len; 18321da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 18331a028e50SDavid S. Miller csum2 = csum_partial(vaddr + frag->page_offset + 18341a028e50SDavid S. Miller offset - start, copy, 0); 18351da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 18361da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 18371da177e4SLinus Torvalds if (!(len -= copy)) 18381da177e4SLinus Torvalds return csum; 18391da177e4SLinus Torvalds offset += copy; 18401da177e4SLinus Torvalds pos += copy; 18411da177e4SLinus Torvalds } 18421a028e50SDavid S. Miller start = end; 18431da177e4SLinus Torvalds } 18441da177e4SLinus Torvalds 1845fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 18461a028e50SDavid S. Miller int end; 18471da177e4SLinus Torvalds 1848547b792cSIlpo Järvinen WARN_ON(start > offset + len); 18491a028e50SDavid S. Miller 1850fbb398a8SDavid S. Miller end = start + frag_iter->len; 18511da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 18525f92a738SAl Viro __wsum csum2; 18531da177e4SLinus Torvalds if (copy > len) 18541da177e4SLinus Torvalds copy = len; 1855fbb398a8SDavid S. Miller csum2 = skb_checksum(frag_iter, offset - start, 18561a028e50SDavid S. Miller copy, 0); 18571da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 18581da177e4SLinus Torvalds if ((len -= copy) == 0) 18591da177e4SLinus Torvalds return csum; 18601da177e4SLinus Torvalds offset += copy; 18611da177e4SLinus Torvalds pos += copy; 18621da177e4SLinus Torvalds } 18631a028e50SDavid S. Miller start = end; 18641da177e4SLinus Torvalds } 186509a62660SKris Katterjohn BUG_ON(len); 18661da177e4SLinus Torvalds 18671da177e4SLinus Torvalds return csum; 18681da177e4SLinus Torvalds } 1869b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_checksum); 18701da177e4SLinus Torvalds 18711da177e4SLinus Torvalds /* Both of above in one bottle. */ 18721da177e4SLinus Torvalds 187381d77662SAl Viro __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 187481d77662SAl Viro u8 *to, int len, __wsum csum) 18751da177e4SLinus Torvalds { 18761a028e50SDavid S. Miller int start = skb_headlen(skb); 18771a028e50SDavid S. Miller int i, copy = start - offset; 1878fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 18791da177e4SLinus Torvalds int pos = 0; 18801da177e4SLinus Torvalds 18811da177e4SLinus Torvalds /* Copy header. */ 18821da177e4SLinus Torvalds if (copy > 0) { 18831da177e4SLinus Torvalds if (copy > len) 18841da177e4SLinus Torvalds copy = len; 18851da177e4SLinus Torvalds csum = csum_partial_copy_nocheck(skb->data + offset, to, 18861da177e4SLinus Torvalds copy, csum); 18871da177e4SLinus Torvalds if ((len -= copy) == 0) 18881da177e4SLinus Torvalds return csum; 18891da177e4SLinus Torvalds offset += copy; 18901da177e4SLinus Torvalds to += copy; 18911da177e4SLinus Torvalds pos = copy; 18921da177e4SLinus Torvalds } 18931da177e4SLinus Torvalds 18941da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 18951a028e50SDavid S. Miller int end; 18961da177e4SLinus Torvalds 1897547b792cSIlpo Järvinen WARN_ON(start > offset + len); 18981a028e50SDavid S. Miller 18999e903e08SEric Dumazet end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]); 19001da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 19015084205fSAl Viro __wsum csum2; 19021da177e4SLinus Torvalds u8 *vaddr; 19031da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 19041da177e4SLinus Torvalds 19051da177e4SLinus Torvalds if (copy > len) 19061da177e4SLinus Torvalds copy = len; 19071da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 19081da177e4SLinus Torvalds csum2 = csum_partial_copy_nocheck(vaddr + 19091a028e50SDavid S. Miller frag->page_offset + 19101a028e50SDavid S. Miller offset - start, to, 19111a028e50SDavid S. Miller copy, 0); 19121da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 19131da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 19141da177e4SLinus Torvalds if (!(len -= copy)) 19151da177e4SLinus Torvalds return csum; 19161da177e4SLinus Torvalds offset += copy; 19171da177e4SLinus Torvalds to += copy; 19181da177e4SLinus Torvalds pos += copy; 19191da177e4SLinus Torvalds } 19201a028e50SDavid S. Miller start = end; 19211da177e4SLinus Torvalds } 19221da177e4SLinus Torvalds 1923fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 192481d77662SAl Viro __wsum csum2; 19251a028e50SDavid S. Miller int end; 19261da177e4SLinus Torvalds 1927547b792cSIlpo Järvinen WARN_ON(start > offset + len); 19281a028e50SDavid S. Miller 1929fbb398a8SDavid S. Miller end = start + frag_iter->len; 19301da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 19311da177e4SLinus Torvalds if (copy > len) 19321da177e4SLinus Torvalds copy = len; 1933fbb398a8SDavid S. Miller csum2 = skb_copy_and_csum_bits(frag_iter, 19341a028e50SDavid S. Miller offset - start, 19351da177e4SLinus Torvalds to, copy, 0); 19361da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 19371da177e4SLinus Torvalds if ((len -= copy) == 0) 19381da177e4SLinus Torvalds return csum; 19391da177e4SLinus Torvalds offset += copy; 19401da177e4SLinus Torvalds to += copy; 19411da177e4SLinus Torvalds pos += copy; 19421da177e4SLinus Torvalds } 19431a028e50SDavid S. Miller start = end; 19441da177e4SLinus Torvalds } 194509a62660SKris Katterjohn BUG_ON(len); 19461da177e4SLinus Torvalds return csum; 19471da177e4SLinus Torvalds } 1948b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_and_csum_bits); 19491da177e4SLinus Torvalds 19501da177e4SLinus Torvalds void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) 19511da177e4SLinus Torvalds { 1952d3bc23e7SAl Viro __wsum csum; 19531da177e4SLinus Torvalds long csstart; 19541da177e4SLinus Torvalds 195584fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) 195655508d60SMichał Mirosław csstart = skb_checksum_start_offset(skb); 19571da177e4SLinus Torvalds else 19581da177e4SLinus Torvalds csstart = skb_headlen(skb); 19591da177e4SLinus Torvalds 196009a62660SKris Katterjohn BUG_ON(csstart > skb_headlen(skb)); 19611da177e4SLinus Torvalds 1962d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data(skb, to, csstart); 19631da177e4SLinus Torvalds 19641da177e4SLinus Torvalds csum = 0; 19651da177e4SLinus Torvalds if (csstart != skb->len) 19661da177e4SLinus Torvalds csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, 19671da177e4SLinus Torvalds skb->len - csstart, 0); 19681da177e4SLinus Torvalds 196984fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) { 1970ff1dcadbSAl Viro long csstuff = csstart + skb->csum_offset; 19711da177e4SLinus Torvalds 1972d3bc23e7SAl Viro *((__sum16 *)(to + csstuff)) = csum_fold(csum); 19731da177e4SLinus Torvalds } 19741da177e4SLinus Torvalds } 1975b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_and_csum_dev); 19761da177e4SLinus Torvalds 19771da177e4SLinus Torvalds /** 19781da177e4SLinus Torvalds * skb_dequeue - remove from the head of the queue 19791da177e4SLinus Torvalds * @list: list to dequeue from 19801da177e4SLinus Torvalds * 19811da177e4SLinus Torvalds * Remove the head of the list. The list lock is taken so the function 19821da177e4SLinus Torvalds * may be used safely with other locking list functions. The head item is 19831da177e4SLinus Torvalds * returned or %NULL if the list is empty. 19841da177e4SLinus Torvalds */ 19851da177e4SLinus Torvalds 19861da177e4SLinus Torvalds struct sk_buff *skb_dequeue(struct sk_buff_head *list) 19871da177e4SLinus Torvalds { 19881da177e4SLinus Torvalds unsigned long flags; 19891da177e4SLinus Torvalds struct sk_buff *result; 19901da177e4SLinus Torvalds 19911da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 19921da177e4SLinus Torvalds result = __skb_dequeue(list); 19931da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 19941da177e4SLinus Torvalds return result; 19951da177e4SLinus Torvalds } 1996b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_dequeue); 19971da177e4SLinus Torvalds 19981da177e4SLinus Torvalds /** 19991da177e4SLinus Torvalds * skb_dequeue_tail - remove from the tail of the queue 20001da177e4SLinus Torvalds * @list: list to dequeue from 20011da177e4SLinus Torvalds * 20021da177e4SLinus Torvalds * Remove the tail of the list. The list lock is taken so the function 20031da177e4SLinus Torvalds * may be used safely with other locking list functions. The tail item is 20041da177e4SLinus Torvalds * returned or %NULL if the list is empty. 20051da177e4SLinus Torvalds */ 20061da177e4SLinus Torvalds struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) 20071da177e4SLinus Torvalds { 20081da177e4SLinus Torvalds unsigned long flags; 20091da177e4SLinus Torvalds struct sk_buff *result; 20101da177e4SLinus Torvalds 20111da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 20121da177e4SLinus Torvalds result = __skb_dequeue_tail(list); 20131da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 20141da177e4SLinus Torvalds return result; 20151da177e4SLinus Torvalds } 2016b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_dequeue_tail); 20171da177e4SLinus Torvalds 20181da177e4SLinus Torvalds /** 20191da177e4SLinus Torvalds * skb_queue_purge - empty a list 20201da177e4SLinus Torvalds * @list: list to empty 20211da177e4SLinus Torvalds * 20221da177e4SLinus Torvalds * Delete all buffers on an &sk_buff list. Each buffer is removed from 20231da177e4SLinus Torvalds * the list and one reference dropped. This function takes the list 20241da177e4SLinus Torvalds * lock and is atomic with respect to other list locking functions. 20251da177e4SLinus Torvalds */ 20261da177e4SLinus Torvalds void skb_queue_purge(struct sk_buff_head *list) 20271da177e4SLinus Torvalds { 20281da177e4SLinus Torvalds struct sk_buff *skb; 20291da177e4SLinus Torvalds while ((skb = skb_dequeue(list)) != NULL) 20301da177e4SLinus Torvalds kfree_skb(skb); 20311da177e4SLinus Torvalds } 2032b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_purge); 20331da177e4SLinus Torvalds 20341da177e4SLinus Torvalds /** 20351da177e4SLinus Torvalds * skb_queue_head - queue a buffer at the list head 20361da177e4SLinus Torvalds * @list: list to use 20371da177e4SLinus Torvalds * @newsk: buffer to queue 20381da177e4SLinus Torvalds * 20391da177e4SLinus Torvalds * Queue a buffer at the start of the list. This function takes the 20401da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 20411da177e4SLinus Torvalds * safely. 20421da177e4SLinus Torvalds * 20431da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 20441da177e4SLinus Torvalds */ 20451da177e4SLinus Torvalds void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) 20461da177e4SLinus Torvalds { 20471da177e4SLinus Torvalds unsigned long flags; 20481da177e4SLinus Torvalds 20491da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 20501da177e4SLinus Torvalds __skb_queue_head(list, newsk); 20511da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 20521da177e4SLinus Torvalds } 2053b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_head); 20541da177e4SLinus Torvalds 20551da177e4SLinus Torvalds /** 20561da177e4SLinus Torvalds * skb_queue_tail - queue a buffer at the list tail 20571da177e4SLinus Torvalds * @list: list to use 20581da177e4SLinus Torvalds * @newsk: buffer to queue 20591da177e4SLinus Torvalds * 20601da177e4SLinus Torvalds * Queue a buffer at the tail of the list. This function takes the 20611da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 20621da177e4SLinus Torvalds * safely. 20631da177e4SLinus Torvalds * 20641da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 20651da177e4SLinus Torvalds */ 20661da177e4SLinus Torvalds void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) 20671da177e4SLinus Torvalds { 20681da177e4SLinus Torvalds unsigned long flags; 20691da177e4SLinus Torvalds 20701da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 20711da177e4SLinus Torvalds __skb_queue_tail(list, newsk); 20721da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 20731da177e4SLinus Torvalds } 2074b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_tail); 20758728b834SDavid S. Miller 20761da177e4SLinus Torvalds /** 20771da177e4SLinus Torvalds * skb_unlink - remove a buffer from a list 20781da177e4SLinus Torvalds * @skb: buffer to remove 20798728b834SDavid S. Miller * @list: list to use 20801da177e4SLinus Torvalds * 20818728b834SDavid S. Miller * Remove a packet from a list. The list locks are taken and this 20828728b834SDavid S. Miller * function is atomic with respect to other list locked calls 20831da177e4SLinus Torvalds * 20848728b834SDavid S. Miller * You must know what list the SKB is on. 20851da177e4SLinus Torvalds */ 20868728b834SDavid S. Miller void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 20871da177e4SLinus Torvalds { 20881da177e4SLinus Torvalds unsigned long flags; 20891da177e4SLinus Torvalds 20901da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 20918728b834SDavid S. Miller __skb_unlink(skb, list); 20921da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 20931da177e4SLinus Torvalds } 2094b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_unlink); 20951da177e4SLinus Torvalds 20961da177e4SLinus Torvalds /** 20971da177e4SLinus Torvalds * skb_append - append a buffer 20981da177e4SLinus Torvalds * @old: buffer to insert after 20991da177e4SLinus Torvalds * @newsk: buffer to insert 21008728b834SDavid S. Miller * @list: list to use 21011da177e4SLinus Torvalds * 21021da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 21031da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls. 21041da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 21051da177e4SLinus Torvalds */ 21068728b834SDavid S. Miller void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 21071da177e4SLinus Torvalds { 21081da177e4SLinus Torvalds unsigned long flags; 21091da177e4SLinus Torvalds 21108728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 21117de6c033SGerrit Renker __skb_queue_after(list, old, newsk); 21128728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 21131da177e4SLinus Torvalds } 2114b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_append); 21151da177e4SLinus Torvalds 21161da177e4SLinus Torvalds /** 21171da177e4SLinus Torvalds * skb_insert - insert a buffer 21181da177e4SLinus Torvalds * @old: buffer to insert before 21191da177e4SLinus Torvalds * @newsk: buffer to insert 21208728b834SDavid S. Miller * @list: list to use 21211da177e4SLinus Torvalds * 21228728b834SDavid S. Miller * Place a packet before a given packet in a list. The list locks are 21238728b834SDavid S. Miller * taken and this function is atomic with respect to other list locked 21248728b834SDavid S. Miller * calls. 21258728b834SDavid S. Miller * 21261da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 21271da177e4SLinus Torvalds */ 21288728b834SDavid S. Miller void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 21291da177e4SLinus Torvalds { 21301da177e4SLinus Torvalds unsigned long flags; 21311da177e4SLinus Torvalds 21328728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 21338728b834SDavid S. Miller __skb_insert(newsk, old->prev, old, list); 21348728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 21351da177e4SLinus Torvalds } 2136b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_insert); 21371da177e4SLinus Torvalds 21381da177e4SLinus Torvalds static inline void skb_split_inside_header(struct sk_buff *skb, 21391da177e4SLinus Torvalds struct sk_buff* skb1, 21401da177e4SLinus Torvalds const u32 len, const int pos) 21411da177e4SLinus Torvalds { 21421da177e4SLinus Torvalds int i; 21431da177e4SLinus Torvalds 2144d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len), 2145d626f62bSArnaldo Carvalho de Melo pos - len); 21461da177e4SLinus Torvalds /* And move data appendix as is. */ 21471da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 21481da177e4SLinus Torvalds skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; 21491da177e4SLinus Torvalds 21501da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; 21511da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 21521da177e4SLinus Torvalds skb1->data_len = skb->data_len; 21531da177e4SLinus Torvalds skb1->len += skb1->data_len; 21541da177e4SLinus Torvalds skb->data_len = 0; 21551da177e4SLinus Torvalds skb->len = len; 215627a884dcSArnaldo Carvalho de Melo skb_set_tail_pointer(skb, len); 21571da177e4SLinus Torvalds } 21581da177e4SLinus Torvalds 21591da177e4SLinus Torvalds static inline void skb_split_no_header(struct sk_buff *skb, 21601da177e4SLinus Torvalds struct sk_buff* skb1, 21611da177e4SLinus Torvalds const u32 len, int pos) 21621da177e4SLinus Torvalds { 21631da177e4SLinus Torvalds int i, k = 0; 21641da177e4SLinus Torvalds const int nfrags = skb_shinfo(skb)->nr_frags; 21651da177e4SLinus Torvalds 21661da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 21671da177e4SLinus Torvalds skb1->len = skb1->data_len = skb->len - len; 21681da177e4SLinus Torvalds skb->len = len; 21691da177e4SLinus Torvalds skb->data_len = len - pos; 21701da177e4SLinus Torvalds 21711da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 21729e903e08SEric Dumazet int size = skb_frag_size(&skb_shinfo(skb)->frags[i]); 21731da177e4SLinus Torvalds 21741da177e4SLinus Torvalds if (pos + size > len) { 21751da177e4SLinus Torvalds skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; 21761da177e4SLinus Torvalds 21771da177e4SLinus Torvalds if (pos < len) { 21781da177e4SLinus Torvalds /* Split frag. 21791da177e4SLinus Torvalds * We have two variants in this case: 21801da177e4SLinus Torvalds * 1. Move all the frag to the second 21811da177e4SLinus Torvalds * part, if it is possible. F.e. 21821da177e4SLinus Torvalds * this approach is mandatory for TUX, 21831da177e4SLinus Torvalds * where splitting is expensive. 21841da177e4SLinus Torvalds * 2. Split is accurately. We make this. 21851da177e4SLinus Torvalds */ 2186ea2ab693SIan Campbell skb_frag_ref(skb, i); 21871da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].page_offset += len - pos; 21889e903e08SEric Dumazet skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos); 21899e903e08SEric Dumazet skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos); 21901da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 21911da177e4SLinus Torvalds } 21921da177e4SLinus Torvalds k++; 21931da177e4SLinus Torvalds } else 21941da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 21951da177e4SLinus Torvalds pos += size; 21961da177e4SLinus Torvalds } 21971da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = k; 21981da177e4SLinus Torvalds } 21991da177e4SLinus Torvalds 22001da177e4SLinus Torvalds /** 22011da177e4SLinus Torvalds * skb_split - Split fragmented skb to two parts at length len. 22021da177e4SLinus Torvalds * @skb: the buffer to split 22031da177e4SLinus Torvalds * @skb1: the buffer to receive the second part 22041da177e4SLinus Torvalds * @len: new length for skb 22051da177e4SLinus Torvalds */ 22061da177e4SLinus Torvalds void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) 22071da177e4SLinus Torvalds { 22081da177e4SLinus Torvalds int pos = skb_headlen(skb); 22091da177e4SLinus Torvalds 22101da177e4SLinus Torvalds if (len < pos) /* Split line is inside header. */ 22111da177e4SLinus Torvalds skb_split_inside_header(skb, skb1, len, pos); 22121da177e4SLinus Torvalds else /* Second chunk has no header, nothing to copy. */ 22131da177e4SLinus Torvalds skb_split_no_header(skb, skb1, len, pos); 22141da177e4SLinus Torvalds } 2215b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_split); 22161da177e4SLinus Torvalds 22179f782db3SIlpo Järvinen /* Shifting from/to a cloned skb is a no-go. 22189f782db3SIlpo Järvinen * 22199f782db3SIlpo Järvinen * Caller cannot keep skb_shinfo related pointers past calling here! 22209f782db3SIlpo Järvinen */ 2221832d11c5SIlpo Järvinen static int skb_prepare_for_shift(struct sk_buff *skb) 2222832d11c5SIlpo Järvinen { 22230ace2856SIlpo Järvinen return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC); 2224832d11c5SIlpo Järvinen } 2225832d11c5SIlpo Järvinen 2226832d11c5SIlpo Järvinen /** 2227832d11c5SIlpo Järvinen * skb_shift - Shifts paged data partially from skb to another 2228832d11c5SIlpo Järvinen * @tgt: buffer into which tail data gets added 2229832d11c5SIlpo Järvinen * @skb: buffer from which the paged data comes from 2230832d11c5SIlpo Järvinen * @shiftlen: shift up to this many bytes 2231832d11c5SIlpo Järvinen * 2232832d11c5SIlpo Järvinen * Attempts to shift up to shiftlen worth of bytes, which may be less than 223320e994a0SFeng King * the length of the skb, from skb to tgt. Returns number bytes shifted. 2234832d11c5SIlpo Järvinen * It's up to caller to free skb if everything was shifted. 2235832d11c5SIlpo Järvinen * 2236832d11c5SIlpo Järvinen * If @tgt runs out of frags, the whole operation is aborted. 2237832d11c5SIlpo Järvinen * 2238832d11c5SIlpo Järvinen * Skb cannot include anything else but paged data while tgt is allowed 2239832d11c5SIlpo Järvinen * to have non-paged data as well. 2240832d11c5SIlpo Järvinen * 2241832d11c5SIlpo Järvinen * TODO: full sized shift could be optimized but that would need 2242832d11c5SIlpo Järvinen * specialized skb free'er to handle frags without up-to-date nr_frags. 2243832d11c5SIlpo Järvinen */ 2244832d11c5SIlpo Järvinen int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) 2245832d11c5SIlpo Järvinen { 2246832d11c5SIlpo Järvinen int from, to, merge, todo; 2247832d11c5SIlpo Järvinen struct skb_frag_struct *fragfrom, *fragto; 2248832d11c5SIlpo Järvinen 2249832d11c5SIlpo Järvinen BUG_ON(shiftlen > skb->len); 2250832d11c5SIlpo Järvinen BUG_ON(skb_headlen(skb)); /* Would corrupt stream */ 2251832d11c5SIlpo Järvinen 2252832d11c5SIlpo Järvinen todo = shiftlen; 2253832d11c5SIlpo Järvinen from = 0; 2254832d11c5SIlpo Järvinen to = skb_shinfo(tgt)->nr_frags; 2255832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 2256832d11c5SIlpo Järvinen 2257832d11c5SIlpo Järvinen /* Actual merge is delayed until the point when we know we can 2258832d11c5SIlpo Järvinen * commit all, so that we don't have to undo partial changes 2259832d11c5SIlpo Järvinen */ 2260832d11c5SIlpo Järvinen if (!to || 2261ea2ab693SIan Campbell !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom), 2262ea2ab693SIan Campbell fragfrom->page_offset)) { 2263832d11c5SIlpo Järvinen merge = -1; 2264832d11c5SIlpo Järvinen } else { 2265832d11c5SIlpo Järvinen merge = to - 1; 2266832d11c5SIlpo Järvinen 22679e903e08SEric Dumazet todo -= skb_frag_size(fragfrom); 2268832d11c5SIlpo Järvinen if (todo < 0) { 2269832d11c5SIlpo Järvinen if (skb_prepare_for_shift(skb) || 2270832d11c5SIlpo Järvinen skb_prepare_for_shift(tgt)) 2271832d11c5SIlpo Järvinen return 0; 2272832d11c5SIlpo Järvinen 22739f782db3SIlpo Järvinen /* All previous frag pointers might be stale! */ 22749f782db3SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 2275832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[merge]; 2276832d11c5SIlpo Järvinen 22779e903e08SEric Dumazet skb_frag_size_add(fragto, shiftlen); 22789e903e08SEric Dumazet skb_frag_size_sub(fragfrom, shiftlen); 2279832d11c5SIlpo Järvinen fragfrom->page_offset += shiftlen; 2280832d11c5SIlpo Järvinen 2281832d11c5SIlpo Järvinen goto onlymerged; 2282832d11c5SIlpo Järvinen } 2283832d11c5SIlpo Järvinen 2284832d11c5SIlpo Järvinen from++; 2285832d11c5SIlpo Järvinen } 2286832d11c5SIlpo Järvinen 2287832d11c5SIlpo Järvinen /* Skip full, not-fitting skb to avoid expensive operations */ 2288832d11c5SIlpo Järvinen if ((shiftlen == skb->len) && 2289832d11c5SIlpo Järvinen (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to)) 2290832d11c5SIlpo Järvinen return 0; 2291832d11c5SIlpo Järvinen 2292832d11c5SIlpo Järvinen if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt)) 2293832d11c5SIlpo Järvinen return 0; 2294832d11c5SIlpo Järvinen 2295832d11c5SIlpo Järvinen while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) { 2296832d11c5SIlpo Järvinen if (to == MAX_SKB_FRAGS) 2297832d11c5SIlpo Järvinen return 0; 2298832d11c5SIlpo Järvinen 2299832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 2300832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[to]; 2301832d11c5SIlpo Järvinen 23029e903e08SEric Dumazet if (todo >= skb_frag_size(fragfrom)) { 2303832d11c5SIlpo Järvinen *fragto = *fragfrom; 23049e903e08SEric Dumazet todo -= skb_frag_size(fragfrom); 2305832d11c5SIlpo Järvinen from++; 2306832d11c5SIlpo Järvinen to++; 2307832d11c5SIlpo Järvinen 2308832d11c5SIlpo Järvinen } else { 2309ea2ab693SIan Campbell __skb_frag_ref(fragfrom); 2310832d11c5SIlpo Järvinen fragto->page = fragfrom->page; 2311832d11c5SIlpo Järvinen fragto->page_offset = fragfrom->page_offset; 23129e903e08SEric Dumazet skb_frag_size_set(fragto, todo); 2313832d11c5SIlpo Järvinen 2314832d11c5SIlpo Järvinen fragfrom->page_offset += todo; 23159e903e08SEric Dumazet skb_frag_size_sub(fragfrom, todo); 2316832d11c5SIlpo Järvinen todo = 0; 2317832d11c5SIlpo Järvinen 2318832d11c5SIlpo Järvinen to++; 2319832d11c5SIlpo Järvinen break; 2320832d11c5SIlpo Järvinen } 2321832d11c5SIlpo Järvinen } 2322832d11c5SIlpo Järvinen 2323832d11c5SIlpo Järvinen /* Ready to "commit" this state change to tgt */ 2324832d11c5SIlpo Järvinen skb_shinfo(tgt)->nr_frags = to; 2325832d11c5SIlpo Järvinen 2326832d11c5SIlpo Järvinen if (merge >= 0) { 2327832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[0]; 2328832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[merge]; 2329832d11c5SIlpo Järvinen 23309e903e08SEric Dumazet skb_frag_size_add(fragto, skb_frag_size(fragfrom)); 2331ea2ab693SIan Campbell __skb_frag_unref(fragfrom); 2332832d11c5SIlpo Järvinen } 2333832d11c5SIlpo Järvinen 2334832d11c5SIlpo Järvinen /* Reposition in the original skb */ 2335832d11c5SIlpo Järvinen to = 0; 2336832d11c5SIlpo Järvinen while (from < skb_shinfo(skb)->nr_frags) 2337832d11c5SIlpo Järvinen skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++]; 2338832d11c5SIlpo Järvinen skb_shinfo(skb)->nr_frags = to; 2339832d11c5SIlpo Järvinen 2340832d11c5SIlpo Järvinen BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags); 2341832d11c5SIlpo Järvinen 2342832d11c5SIlpo Järvinen onlymerged: 2343832d11c5SIlpo Järvinen /* Most likely the tgt won't ever need its checksum anymore, skb on 2344832d11c5SIlpo Järvinen * the other hand might need it if it needs to be resent 2345832d11c5SIlpo Järvinen */ 2346832d11c5SIlpo Järvinen tgt->ip_summed = CHECKSUM_PARTIAL; 2347832d11c5SIlpo Järvinen skb->ip_summed = CHECKSUM_PARTIAL; 2348832d11c5SIlpo Järvinen 2349832d11c5SIlpo Järvinen /* Yak, is it really working this way? Some helper please? */ 2350832d11c5SIlpo Järvinen skb->len -= shiftlen; 2351832d11c5SIlpo Järvinen skb->data_len -= shiftlen; 2352832d11c5SIlpo Järvinen skb->truesize -= shiftlen; 2353832d11c5SIlpo Järvinen tgt->len += shiftlen; 2354832d11c5SIlpo Järvinen tgt->data_len += shiftlen; 2355832d11c5SIlpo Järvinen tgt->truesize += shiftlen; 2356832d11c5SIlpo Järvinen 2357832d11c5SIlpo Järvinen return shiftlen; 2358832d11c5SIlpo Järvinen } 2359832d11c5SIlpo Järvinen 2360677e90edSThomas Graf /** 2361677e90edSThomas Graf * skb_prepare_seq_read - Prepare a sequential read of skb data 2362677e90edSThomas Graf * @skb: the buffer to read 2363677e90edSThomas Graf * @from: lower offset of data to be read 2364677e90edSThomas Graf * @to: upper offset of data to be read 2365677e90edSThomas Graf * @st: state variable 2366677e90edSThomas Graf * 2367677e90edSThomas Graf * Initializes the specified state variable. Must be called before 2368677e90edSThomas Graf * invoking skb_seq_read() for the first time. 2369677e90edSThomas Graf */ 2370677e90edSThomas Graf void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 2371677e90edSThomas Graf unsigned int to, struct skb_seq_state *st) 2372677e90edSThomas Graf { 2373677e90edSThomas Graf st->lower_offset = from; 2374677e90edSThomas Graf st->upper_offset = to; 2375677e90edSThomas Graf st->root_skb = st->cur_skb = skb; 2376677e90edSThomas Graf st->frag_idx = st->stepped_offset = 0; 2377677e90edSThomas Graf st->frag_data = NULL; 2378677e90edSThomas Graf } 2379b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_prepare_seq_read); 2380677e90edSThomas Graf 2381677e90edSThomas Graf /** 2382677e90edSThomas Graf * skb_seq_read - Sequentially read skb data 2383677e90edSThomas Graf * @consumed: number of bytes consumed by the caller so far 2384677e90edSThomas Graf * @data: destination pointer for data to be returned 2385677e90edSThomas Graf * @st: state variable 2386677e90edSThomas Graf * 2387677e90edSThomas Graf * Reads a block of skb data at &consumed relative to the 2388677e90edSThomas Graf * lower offset specified to skb_prepare_seq_read(). Assigns 2389677e90edSThomas Graf * the head of the data block to &data and returns the length 2390677e90edSThomas Graf * of the block or 0 if the end of the skb data or the upper 2391677e90edSThomas Graf * offset has been reached. 2392677e90edSThomas Graf * 2393677e90edSThomas Graf * The caller is not required to consume all of the data 2394677e90edSThomas Graf * returned, i.e. &consumed is typically set to the number 2395677e90edSThomas Graf * of bytes already consumed and the next call to 2396677e90edSThomas Graf * skb_seq_read() will return the remaining part of the block. 2397677e90edSThomas Graf * 239825985edcSLucas De Marchi * Note 1: The size of each block of data returned can be arbitrary, 2399677e90edSThomas Graf * this limitation is the cost for zerocopy seqeuental 2400677e90edSThomas Graf * reads of potentially non linear data. 2401677e90edSThomas Graf * 2402bc2cda1eSRandy Dunlap * Note 2: Fragment lists within fragments are not implemented 2403677e90edSThomas Graf * at the moment, state->root_skb could be replaced with 2404677e90edSThomas Graf * a stack for this purpose. 2405677e90edSThomas Graf */ 2406677e90edSThomas Graf unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 2407677e90edSThomas Graf struct skb_seq_state *st) 2408677e90edSThomas Graf { 2409677e90edSThomas Graf unsigned int block_limit, abs_offset = consumed + st->lower_offset; 2410677e90edSThomas Graf skb_frag_t *frag; 2411677e90edSThomas Graf 2412677e90edSThomas Graf if (unlikely(abs_offset >= st->upper_offset)) 2413677e90edSThomas Graf return 0; 2414677e90edSThomas Graf 2415677e90edSThomas Graf next_skb: 241695e3b24cSHerbert Xu block_limit = skb_headlen(st->cur_skb) + st->stepped_offset; 2417677e90edSThomas Graf 2418995b3379SThomas Chenault if (abs_offset < block_limit && !st->frag_data) { 241995e3b24cSHerbert Xu *data = st->cur_skb->data + (abs_offset - st->stepped_offset); 2420677e90edSThomas Graf return block_limit - abs_offset; 2421677e90edSThomas Graf } 2422677e90edSThomas Graf 2423677e90edSThomas Graf if (st->frag_idx == 0 && !st->frag_data) 2424677e90edSThomas Graf st->stepped_offset += skb_headlen(st->cur_skb); 2425677e90edSThomas Graf 2426677e90edSThomas Graf while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { 2427677e90edSThomas Graf frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; 24289e903e08SEric Dumazet block_limit = skb_frag_size(frag) + st->stepped_offset; 2429677e90edSThomas Graf 2430677e90edSThomas Graf if (abs_offset < block_limit) { 2431677e90edSThomas Graf if (!st->frag_data) 2432677e90edSThomas Graf st->frag_data = kmap_skb_frag(frag); 2433677e90edSThomas Graf 2434677e90edSThomas Graf *data = (u8 *) st->frag_data + frag->page_offset + 2435677e90edSThomas Graf (abs_offset - st->stepped_offset); 2436677e90edSThomas Graf 2437677e90edSThomas Graf return block_limit - abs_offset; 2438677e90edSThomas Graf } 2439677e90edSThomas Graf 2440677e90edSThomas Graf if (st->frag_data) { 2441677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 2442677e90edSThomas Graf st->frag_data = NULL; 2443677e90edSThomas Graf } 2444677e90edSThomas Graf 2445677e90edSThomas Graf st->frag_idx++; 24469e903e08SEric Dumazet st->stepped_offset += skb_frag_size(frag); 2447677e90edSThomas Graf } 2448677e90edSThomas Graf 24495b5a60daSOlaf Kirch if (st->frag_data) { 24505b5a60daSOlaf Kirch kunmap_skb_frag(st->frag_data); 24515b5a60daSOlaf Kirch st->frag_data = NULL; 24525b5a60daSOlaf Kirch } 24535b5a60daSOlaf Kirch 245421dc3301SDavid S. Miller if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) { 2455677e90edSThomas Graf st->cur_skb = skb_shinfo(st->root_skb)->frag_list; 245695e3b24cSHerbert Xu st->frag_idx = 0; 2457677e90edSThomas Graf goto next_skb; 245871b3346dSShyam Iyer } else if (st->cur_skb->next) { 245971b3346dSShyam Iyer st->cur_skb = st->cur_skb->next; 246071b3346dSShyam Iyer st->frag_idx = 0; 2461677e90edSThomas Graf goto next_skb; 2462677e90edSThomas Graf } 2463677e90edSThomas Graf 2464677e90edSThomas Graf return 0; 2465677e90edSThomas Graf } 2466b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_seq_read); 2467677e90edSThomas Graf 2468677e90edSThomas Graf /** 2469677e90edSThomas Graf * skb_abort_seq_read - Abort a sequential read of skb data 2470677e90edSThomas Graf * @st: state variable 2471677e90edSThomas Graf * 2472677e90edSThomas Graf * Must be called if skb_seq_read() was not called until it 2473677e90edSThomas Graf * returned 0. 2474677e90edSThomas Graf */ 2475677e90edSThomas Graf void skb_abort_seq_read(struct skb_seq_state *st) 2476677e90edSThomas Graf { 2477677e90edSThomas Graf if (st->frag_data) 2478677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 2479677e90edSThomas Graf } 2480b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_abort_seq_read); 2481677e90edSThomas Graf 24823fc7e8a6SThomas Graf #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) 24833fc7e8a6SThomas Graf 24843fc7e8a6SThomas Graf static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, 24853fc7e8a6SThomas Graf struct ts_config *conf, 24863fc7e8a6SThomas Graf struct ts_state *state) 24873fc7e8a6SThomas Graf { 24883fc7e8a6SThomas Graf return skb_seq_read(offset, text, TS_SKB_CB(state)); 24893fc7e8a6SThomas Graf } 24903fc7e8a6SThomas Graf 24913fc7e8a6SThomas Graf static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) 24923fc7e8a6SThomas Graf { 24933fc7e8a6SThomas Graf skb_abort_seq_read(TS_SKB_CB(state)); 24943fc7e8a6SThomas Graf } 24953fc7e8a6SThomas Graf 24963fc7e8a6SThomas Graf /** 24973fc7e8a6SThomas Graf * skb_find_text - Find a text pattern in skb data 24983fc7e8a6SThomas Graf * @skb: the buffer to look in 24993fc7e8a6SThomas Graf * @from: search offset 25003fc7e8a6SThomas Graf * @to: search limit 25013fc7e8a6SThomas Graf * @config: textsearch configuration 25023fc7e8a6SThomas Graf * @state: uninitialized textsearch state variable 25033fc7e8a6SThomas Graf * 25043fc7e8a6SThomas Graf * Finds a pattern in the skb data according to the specified 25053fc7e8a6SThomas Graf * textsearch configuration. Use textsearch_next() to retrieve 25063fc7e8a6SThomas Graf * subsequent occurrences of the pattern. Returns the offset 25073fc7e8a6SThomas Graf * to the first occurrence or UINT_MAX if no match was found. 25083fc7e8a6SThomas Graf */ 25093fc7e8a6SThomas Graf unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 25103fc7e8a6SThomas Graf unsigned int to, struct ts_config *config, 25113fc7e8a6SThomas Graf struct ts_state *state) 25123fc7e8a6SThomas Graf { 2513f72b948dSPhil Oester unsigned int ret; 2514f72b948dSPhil Oester 25153fc7e8a6SThomas Graf config->get_next_block = skb_ts_get_next_block; 25163fc7e8a6SThomas Graf config->finish = skb_ts_finish; 25173fc7e8a6SThomas Graf 25183fc7e8a6SThomas Graf skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); 25193fc7e8a6SThomas Graf 2520f72b948dSPhil Oester ret = textsearch_find(config, state); 2521f72b948dSPhil Oester return (ret <= to - from ? ret : UINT_MAX); 25223fc7e8a6SThomas Graf } 2523b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_find_text); 25243fc7e8a6SThomas Graf 2525e89e9cf5SAnanda Raju /** 2526e89e9cf5SAnanda Raju * skb_append_datato_frags: - append the user data to a skb 2527e89e9cf5SAnanda Raju * @sk: sock structure 2528e89e9cf5SAnanda Raju * @skb: skb structure to be appened with user data. 2529e89e9cf5SAnanda Raju * @getfrag: call back function to be used for getting the user data 2530e89e9cf5SAnanda Raju * @from: pointer to user message iov 2531e89e9cf5SAnanda Raju * @length: length of the iov message 2532e89e9cf5SAnanda Raju * 2533e89e9cf5SAnanda Raju * Description: This procedure append the user data in the fragment part 2534e89e9cf5SAnanda Raju * of the skb if any page alloc fails user this procedure returns -ENOMEM 2535e89e9cf5SAnanda Raju */ 2536e89e9cf5SAnanda Raju int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, 2537dab9630fSMartin Waitz int (*getfrag)(void *from, char *to, int offset, 2538e89e9cf5SAnanda Raju int len, int odd, struct sk_buff *skb), 2539e89e9cf5SAnanda Raju void *from, int length) 2540e89e9cf5SAnanda Raju { 2541e89e9cf5SAnanda Raju int frg_cnt = 0; 2542e89e9cf5SAnanda Raju skb_frag_t *frag = NULL; 2543e89e9cf5SAnanda Raju struct page *page = NULL; 2544e89e9cf5SAnanda Raju int copy, left; 2545e89e9cf5SAnanda Raju int offset = 0; 2546e89e9cf5SAnanda Raju int ret; 2547e89e9cf5SAnanda Raju 2548e89e9cf5SAnanda Raju do { 2549e89e9cf5SAnanda Raju /* Return error if we don't have space for new frag */ 2550e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 2551e89e9cf5SAnanda Raju if (frg_cnt >= MAX_SKB_FRAGS) 2552e89e9cf5SAnanda Raju return -EFAULT; 2553e89e9cf5SAnanda Raju 2554e89e9cf5SAnanda Raju /* allocate a new page for next frag */ 2555e89e9cf5SAnanda Raju page = alloc_pages(sk->sk_allocation, 0); 2556e89e9cf5SAnanda Raju 2557e89e9cf5SAnanda Raju /* If alloc_page fails just return failure and caller will 2558e89e9cf5SAnanda Raju * free previous allocated pages by doing kfree_skb() 2559e89e9cf5SAnanda Raju */ 2560e89e9cf5SAnanda Raju if (page == NULL) 2561e89e9cf5SAnanda Raju return -ENOMEM; 2562e89e9cf5SAnanda Raju 2563e89e9cf5SAnanda Raju /* initialize the next frag */ 2564e89e9cf5SAnanda Raju skb_fill_page_desc(skb, frg_cnt, page, 0, 0); 2565e89e9cf5SAnanda Raju skb->truesize += PAGE_SIZE; 2566e89e9cf5SAnanda Raju atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 2567e89e9cf5SAnanda Raju 2568e89e9cf5SAnanda Raju /* get the new initialized frag */ 2569e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 2570e89e9cf5SAnanda Raju frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; 2571e89e9cf5SAnanda Raju 2572e89e9cf5SAnanda Raju /* copy the user data to page */ 2573e89e9cf5SAnanda Raju left = PAGE_SIZE - frag->page_offset; 2574e89e9cf5SAnanda Raju copy = (length > left)? left : length; 2575e89e9cf5SAnanda Raju 25769e903e08SEric Dumazet ret = getfrag(from, skb_frag_address(frag) + skb_frag_size(frag), 2577e89e9cf5SAnanda Raju offset, copy, 0, skb); 2578e89e9cf5SAnanda Raju if (ret < 0) 2579e89e9cf5SAnanda Raju return -EFAULT; 2580e89e9cf5SAnanda Raju 2581e89e9cf5SAnanda Raju /* copy was successful so update the size parameters */ 25829e903e08SEric Dumazet skb_frag_size_add(frag, copy); 2583e89e9cf5SAnanda Raju skb->len += copy; 2584e89e9cf5SAnanda Raju skb->data_len += copy; 2585e89e9cf5SAnanda Raju offset += copy; 2586e89e9cf5SAnanda Raju length -= copy; 2587e89e9cf5SAnanda Raju 2588e89e9cf5SAnanda Raju } while (length > 0); 2589e89e9cf5SAnanda Raju 2590e89e9cf5SAnanda Raju return 0; 2591e89e9cf5SAnanda Raju } 2592b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_append_datato_frags); 2593e89e9cf5SAnanda Raju 2594cbb042f9SHerbert Xu /** 2595cbb042f9SHerbert Xu * skb_pull_rcsum - pull skb and update receive checksum 2596cbb042f9SHerbert Xu * @skb: buffer to update 2597cbb042f9SHerbert Xu * @len: length of data pulled 2598cbb042f9SHerbert Xu * 2599cbb042f9SHerbert Xu * This function performs an skb_pull on the packet and updates 2600fee54fa5SUrs Thuermann * the CHECKSUM_COMPLETE checksum. It should be used on 260184fa7933SPatrick McHardy * receive path processing instead of skb_pull unless you know 260284fa7933SPatrick McHardy * that the checksum difference is zero (e.g., a valid IP header) 260384fa7933SPatrick McHardy * or you are setting ip_summed to CHECKSUM_NONE. 2604cbb042f9SHerbert Xu */ 2605cbb042f9SHerbert Xu unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) 2606cbb042f9SHerbert Xu { 2607cbb042f9SHerbert Xu BUG_ON(len > skb->len); 2608cbb042f9SHerbert Xu skb->len -= len; 2609cbb042f9SHerbert Xu BUG_ON(skb->len < skb->data_len); 2610cbb042f9SHerbert Xu skb_postpull_rcsum(skb, skb->data, len); 2611cbb042f9SHerbert Xu return skb->data += len; 2612cbb042f9SHerbert Xu } 2613f94691acSArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(skb_pull_rcsum); 2614f94691acSArnaldo Carvalho de Melo 2615f4c50d99SHerbert Xu /** 2616f4c50d99SHerbert Xu * skb_segment - Perform protocol segmentation on skb. 2617f4c50d99SHerbert Xu * @skb: buffer to segment 2618576a30ebSHerbert Xu * @features: features for the output path (see dev->features) 2619f4c50d99SHerbert Xu * 2620f4c50d99SHerbert Xu * This function performs segmentation on the given skb. It returns 26214c821d75SBen Hutchings * a pointer to the first in a list of new skbs for the segments. 26224c821d75SBen Hutchings * In case of error it returns ERR_PTR(err). 2623f4c50d99SHerbert Xu */ 262404ed3e74SMichał Mirosław struct sk_buff *skb_segment(struct sk_buff *skb, u32 features) 2625f4c50d99SHerbert Xu { 2626f4c50d99SHerbert Xu struct sk_buff *segs = NULL; 2627f4c50d99SHerbert Xu struct sk_buff *tail = NULL; 262889319d38SHerbert Xu struct sk_buff *fskb = skb_shinfo(skb)->frag_list; 2629f4c50d99SHerbert Xu unsigned int mss = skb_shinfo(skb)->gso_size; 263098e399f8SArnaldo Carvalho de Melo unsigned int doffset = skb->data - skb_mac_header(skb); 2631f4c50d99SHerbert Xu unsigned int offset = doffset; 2632f4c50d99SHerbert Xu unsigned int headroom; 2633f4c50d99SHerbert Xu unsigned int len; 263404ed3e74SMichał Mirosław int sg = !!(features & NETIF_F_SG); 2635f4c50d99SHerbert Xu int nfrags = skb_shinfo(skb)->nr_frags; 2636f4c50d99SHerbert Xu int err = -ENOMEM; 2637f4c50d99SHerbert Xu int i = 0; 2638f4c50d99SHerbert Xu int pos; 2639f4c50d99SHerbert Xu 2640f4c50d99SHerbert Xu __skb_push(skb, doffset); 2641f4c50d99SHerbert Xu headroom = skb_headroom(skb); 2642f4c50d99SHerbert Xu pos = skb_headlen(skb); 2643f4c50d99SHerbert Xu 2644f4c50d99SHerbert Xu do { 2645f4c50d99SHerbert Xu struct sk_buff *nskb; 2646f4c50d99SHerbert Xu skb_frag_t *frag; 2647c8884eddSHerbert Xu int hsize; 2648f4c50d99SHerbert Xu int size; 2649f4c50d99SHerbert Xu 2650f4c50d99SHerbert Xu len = skb->len - offset; 2651f4c50d99SHerbert Xu if (len > mss) 2652f4c50d99SHerbert Xu len = mss; 2653f4c50d99SHerbert Xu 2654f4c50d99SHerbert Xu hsize = skb_headlen(skb) - offset; 2655f4c50d99SHerbert Xu if (hsize < 0) 2656f4c50d99SHerbert Xu hsize = 0; 2657c8884eddSHerbert Xu if (hsize > len || !sg) 2658c8884eddSHerbert Xu hsize = len; 2659f4c50d99SHerbert Xu 266089319d38SHerbert Xu if (!hsize && i >= nfrags) { 266189319d38SHerbert Xu BUG_ON(fskb->len != len); 266289319d38SHerbert Xu 266389319d38SHerbert Xu pos += len; 266489319d38SHerbert Xu nskb = skb_clone(fskb, GFP_ATOMIC); 266589319d38SHerbert Xu fskb = fskb->next; 266689319d38SHerbert Xu 2667f4c50d99SHerbert Xu if (unlikely(!nskb)) 2668f4c50d99SHerbert Xu goto err; 2669f4c50d99SHerbert Xu 267089319d38SHerbert Xu hsize = skb_end_pointer(nskb) - nskb->head; 267189319d38SHerbert Xu if (skb_cow_head(nskb, doffset + headroom)) { 267289319d38SHerbert Xu kfree_skb(nskb); 267389319d38SHerbert Xu goto err; 267489319d38SHerbert Xu } 267589319d38SHerbert Xu 267689319d38SHerbert Xu nskb->truesize += skb_end_pointer(nskb) - nskb->head - 267789319d38SHerbert Xu hsize; 267889319d38SHerbert Xu skb_release_head_state(nskb); 267989319d38SHerbert Xu __skb_push(nskb, doffset); 268089319d38SHerbert Xu } else { 268189319d38SHerbert Xu nskb = alloc_skb(hsize + doffset + headroom, 268289319d38SHerbert Xu GFP_ATOMIC); 268389319d38SHerbert Xu 268489319d38SHerbert Xu if (unlikely(!nskb)) 268589319d38SHerbert Xu goto err; 268689319d38SHerbert Xu 268789319d38SHerbert Xu skb_reserve(nskb, headroom); 268889319d38SHerbert Xu __skb_put(nskb, doffset); 268989319d38SHerbert Xu } 269089319d38SHerbert Xu 2691f4c50d99SHerbert Xu if (segs) 2692f4c50d99SHerbert Xu tail->next = nskb; 2693f4c50d99SHerbert Xu else 2694f4c50d99SHerbert Xu segs = nskb; 2695f4c50d99SHerbert Xu tail = nskb; 2696f4c50d99SHerbert Xu 26976f85a124SHerbert Xu __copy_skb_header(nskb, skb); 2698f4c50d99SHerbert Xu nskb->mac_len = skb->mac_len; 2699f4c50d99SHerbert Xu 27003d3be433SEric Dumazet /* nskb and skb might have different headroom */ 27013d3be433SEric Dumazet if (nskb->ip_summed == CHECKSUM_PARTIAL) 27023d3be433SEric Dumazet nskb->csum_start += skb_headroom(nskb) - headroom; 27033d3be433SEric Dumazet 2704459a98edSArnaldo Carvalho de Melo skb_reset_mac_header(nskb); 2705ddc7b8e3SArnaldo Carvalho de Melo skb_set_network_header(nskb, skb->mac_len); 2706b0e380b1SArnaldo Carvalho de Melo nskb->transport_header = (nskb->network_header + 2707b0e380b1SArnaldo Carvalho de Melo skb_network_header_len(skb)); 270889319d38SHerbert Xu skb_copy_from_linear_data(skb, nskb->data, doffset); 270989319d38SHerbert Xu 27102f181855SHerbert Xu if (fskb != skb_shinfo(skb)->frag_list) 271189319d38SHerbert Xu continue; 271289319d38SHerbert Xu 2713f4c50d99SHerbert Xu if (!sg) { 27146f85a124SHerbert Xu nskb->ip_summed = CHECKSUM_NONE; 2715f4c50d99SHerbert Xu nskb->csum = skb_copy_and_csum_bits(skb, offset, 2716f4c50d99SHerbert Xu skb_put(nskb, len), 2717f4c50d99SHerbert Xu len, 0); 2718f4c50d99SHerbert Xu continue; 2719f4c50d99SHerbert Xu } 2720f4c50d99SHerbert Xu 2721f4c50d99SHerbert Xu frag = skb_shinfo(nskb)->frags; 2722f4c50d99SHerbert Xu 2723d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, offset, 2724d626f62bSArnaldo Carvalho de Melo skb_put(nskb, hsize), hsize); 2725f4c50d99SHerbert Xu 272689319d38SHerbert Xu while (pos < offset + len && i < nfrags) { 2727f4c50d99SHerbert Xu *frag = skb_shinfo(skb)->frags[i]; 2728ea2ab693SIan Campbell __skb_frag_ref(frag); 27299e903e08SEric Dumazet size = skb_frag_size(frag); 2730f4c50d99SHerbert Xu 2731f4c50d99SHerbert Xu if (pos < offset) { 2732f4c50d99SHerbert Xu frag->page_offset += offset - pos; 27339e903e08SEric Dumazet skb_frag_size_sub(frag, offset - pos); 2734f4c50d99SHerbert Xu } 2735f4c50d99SHerbert Xu 273689319d38SHerbert Xu skb_shinfo(nskb)->nr_frags++; 2737f4c50d99SHerbert Xu 2738f4c50d99SHerbert Xu if (pos + size <= offset + len) { 2739f4c50d99SHerbert Xu i++; 2740f4c50d99SHerbert Xu pos += size; 2741f4c50d99SHerbert Xu } else { 27429e903e08SEric Dumazet skb_frag_size_sub(frag, pos + size - (offset + len)); 274389319d38SHerbert Xu goto skip_fraglist; 2744f4c50d99SHerbert Xu } 2745f4c50d99SHerbert Xu 2746f4c50d99SHerbert Xu frag++; 2747f4c50d99SHerbert Xu } 2748f4c50d99SHerbert Xu 274989319d38SHerbert Xu if (pos < offset + len) { 275089319d38SHerbert Xu struct sk_buff *fskb2 = fskb; 275189319d38SHerbert Xu 275289319d38SHerbert Xu BUG_ON(pos + fskb->len != offset + len); 275389319d38SHerbert Xu 275489319d38SHerbert Xu pos += fskb->len; 275589319d38SHerbert Xu fskb = fskb->next; 275689319d38SHerbert Xu 275789319d38SHerbert Xu if (fskb2->next) { 275889319d38SHerbert Xu fskb2 = skb_clone(fskb2, GFP_ATOMIC); 275989319d38SHerbert Xu if (!fskb2) 276089319d38SHerbert Xu goto err; 276189319d38SHerbert Xu } else 276289319d38SHerbert Xu skb_get(fskb2); 276389319d38SHerbert Xu 2764fbb398a8SDavid S. Miller SKB_FRAG_ASSERT(nskb); 276589319d38SHerbert Xu skb_shinfo(nskb)->frag_list = fskb2; 276689319d38SHerbert Xu } 276789319d38SHerbert Xu 276889319d38SHerbert Xu skip_fraglist: 2769f4c50d99SHerbert Xu nskb->data_len = len - hsize; 2770f4c50d99SHerbert Xu nskb->len += nskb->data_len; 2771f4c50d99SHerbert Xu nskb->truesize += nskb->data_len; 2772f4c50d99SHerbert Xu } while ((offset += len) < skb->len); 2773f4c50d99SHerbert Xu 2774f4c50d99SHerbert Xu return segs; 2775f4c50d99SHerbert Xu 2776f4c50d99SHerbert Xu err: 2777f4c50d99SHerbert Xu while ((skb = segs)) { 2778f4c50d99SHerbert Xu segs = skb->next; 2779b08d5840SPatrick McHardy kfree_skb(skb); 2780f4c50d99SHerbert Xu } 2781f4c50d99SHerbert Xu return ERR_PTR(err); 2782f4c50d99SHerbert Xu } 2783f4c50d99SHerbert Xu EXPORT_SYMBOL_GPL(skb_segment); 2784f4c50d99SHerbert Xu 278571d93b39SHerbert Xu int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 278671d93b39SHerbert Xu { 278771d93b39SHerbert Xu struct sk_buff *p = *head; 278871d93b39SHerbert Xu struct sk_buff *nskb; 27899aaa156cSHerbert Xu struct skb_shared_info *skbinfo = skb_shinfo(skb); 27909aaa156cSHerbert Xu struct skb_shared_info *pinfo = skb_shinfo(p); 279171d93b39SHerbert Xu unsigned int headroom; 279286911732SHerbert Xu unsigned int len = skb_gro_len(skb); 279367147ba9SHerbert Xu unsigned int offset = skb_gro_offset(skb); 279467147ba9SHerbert Xu unsigned int headlen = skb_headlen(skb); 279571d93b39SHerbert Xu 279686911732SHerbert Xu if (p->len + len >= 65536) 279771d93b39SHerbert Xu return -E2BIG; 279871d93b39SHerbert Xu 27999aaa156cSHerbert Xu if (pinfo->frag_list) 280071d93b39SHerbert Xu goto merge; 280167147ba9SHerbert Xu else if (headlen <= offset) { 280242da6994SHerbert Xu skb_frag_t *frag; 280366e92fcfSHerbert Xu skb_frag_t *frag2; 28049aaa156cSHerbert Xu int i = skbinfo->nr_frags; 28059aaa156cSHerbert Xu int nr_frags = pinfo->nr_frags + i; 280642da6994SHerbert Xu 280766e92fcfSHerbert Xu offset -= headlen; 280866e92fcfSHerbert Xu 280966e92fcfSHerbert Xu if (nr_frags > MAX_SKB_FRAGS) 281081705ad1SHerbert Xu return -E2BIG; 281181705ad1SHerbert Xu 28129aaa156cSHerbert Xu pinfo->nr_frags = nr_frags; 28139aaa156cSHerbert Xu skbinfo->nr_frags = 0; 2814f5572068SHerbert Xu 28159aaa156cSHerbert Xu frag = pinfo->frags + nr_frags; 28169aaa156cSHerbert Xu frag2 = skbinfo->frags + i; 281766e92fcfSHerbert Xu do { 281866e92fcfSHerbert Xu *--frag = *--frag2; 281966e92fcfSHerbert Xu } while (--i); 282066e92fcfSHerbert Xu 282166e92fcfSHerbert Xu frag->page_offset += offset; 28229e903e08SEric Dumazet skb_frag_size_sub(frag, offset); 282366e92fcfSHerbert Xu 2824f5572068SHerbert Xu skb->truesize -= skb->data_len; 2825f5572068SHerbert Xu skb->len -= skb->data_len; 2826f5572068SHerbert Xu skb->data_len = 0; 2827f5572068SHerbert Xu 28285d38a079SHerbert Xu NAPI_GRO_CB(skb)->free = 1; 28295d38a079SHerbert Xu goto done; 283069c0cab1SHerbert Xu } else if (skb_gro_len(p) != pinfo->gso_size) 283169c0cab1SHerbert Xu return -E2BIG; 283271d93b39SHerbert Xu 283371d93b39SHerbert Xu headroom = skb_headroom(p); 28343d3be433SEric Dumazet nskb = alloc_skb(headroom + skb_gro_offset(p), GFP_ATOMIC); 283571d93b39SHerbert Xu if (unlikely(!nskb)) 283671d93b39SHerbert Xu return -ENOMEM; 283771d93b39SHerbert Xu 283871d93b39SHerbert Xu __copy_skb_header(nskb, p); 283971d93b39SHerbert Xu nskb->mac_len = p->mac_len; 284071d93b39SHerbert Xu 284171d93b39SHerbert Xu skb_reserve(nskb, headroom); 284286911732SHerbert Xu __skb_put(nskb, skb_gro_offset(p)); 284371d93b39SHerbert Xu 284486911732SHerbert Xu skb_set_mac_header(nskb, skb_mac_header(p) - p->data); 284571d93b39SHerbert Xu skb_set_network_header(nskb, skb_network_offset(p)); 284671d93b39SHerbert Xu skb_set_transport_header(nskb, skb_transport_offset(p)); 284771d93b39SHerbert Xu 284886911732SHerbert Xu __skb_pull(p, skb_gro_offset(p)); 284986911732SHerbert Xu memcpy(skb_mac_header(nskb), skb_mac_header(p), 285086911732SHerbert Xu p->data - skb_mac_header(p)); 285171d93b39SHerbert Xu 285271d93b39SHerbert Xu *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p); 285371d93b39SHerbert Xu skb_shinfo(nskb)->frag_list = p; 28549aaa156cSHerbert Xu skb_shinfo(nskb)->gso_size = pinfo->gso_size; 2855622e0ca1SHerbert Xu pinfo->gso_size = 0; 285671d93b39SHerbert Xu skb_header_release(p); 285771d93b39SHerbert Xu nskb->prev = p; 285871d93b39SHerbert Xu 285971d93b39SHerbert Xu nskb->data_len += p->len; 286071d93b39SHerbert Xu nskb->truesize += p->len; 286171d93b39SHerbert Xu nskb->len += p->len; 286271d93b39SHerbert Xu 286371d93b39SHerbert Xu *head = nskb; 286471d93b39SHerbert Xu nskb->next = p->next; 286571d93b39SHerbert Xu p->next = NULL; 286671d93b39SHerbert Xu 286771d93b39SHerbert Xu p = nskb; 286871d93b39SHerbert Xu 286971d93b39SHerbert Xu merge: 287067147ba9SHerbert Xu if (offset > headlen) { 2871d1dc7abfSMichal Schmidt unsigned int eat = offset - headlen; 2872d1dc7abfSMichal Schmidt 2873d1dc7abfSMichal Schmidt skbinfo->frags[0].page_offset += eat; 28749e903e08SEric Dumazet skb_frag_size_sub(&skbinfo->frags[0], eat); 2875d1dc7abfSMichal Schmidt skb->data_len -= eat; 2876d1dc7abfSMichal Schmidt skb->len -= eat; 287767147ba9SHerbert Xu offset = headlen; 287856035022SHerbert Xu } 287956035022SHerbert Xu 288067147ba9SHerbert Xu __skb_pull(skb, offset); 288156035022SHerbert Xu 288271d93b39SHerbert Xu p->prev->next = skb; 288371d93b39SHerbert Xu p->prev = skb; 288471d93b39SHerbert Xu skb_header_release(skb); 288571d93b39SHerbert Xu 28865d38a079SHerbert Xu done: 28875d38a079SHerbert Xu NAPI_GRO_CB(p)->count++; 288837fe4732SHerbert Xu p->data_len += len; 288937fe4732SHerbert Xu p->truesize += len; 289037fe4732SHerbert Xu p->len += len; 289171d93b39SHerbert Xu 289271d93b39SHerbert Xu NAPI_GRO_CB(skb)->same_flow = 1; 289371d93b39SHerbert Xu return 0; 289471d93b39SHerbert Xu } 289571d93b39SHerbert Xu EXPORT_SYMBOL_GPL(skb_gro_receive); 289671d93b39SHerbert Xu 28971da177e4SLinus Torvalds void __init skb_init(void) 28981da177e4SLinus Torvalds { 28991da177e4SLinus Torvalds skbuff_head_cache = kmem_cache_create("skbuff_head_cache", 29001da177e4SLinus Torvalds sizeof(struct sk_buff), 29011da177e4SLinus Torvalds 0, 2902e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 290320c2df83SPaul Mundt NULL); 2904d179cd12SDavid S. Miller skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", 2905d179cd12SDavid S. Miller (2*sizeof(struct sk_buff)) + 2906d179cd12SDavid S. Miller sizeof(atomic_t), 2907d179cd12SDavid S. Miller 0, 2908e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 290920c2df83SPaul Mundt NULL); 29101da177e4SLinus Torvalds } 29111da177e4SLinus Torvalds 2912716ea3a7SDavid Howells /** 2913716ea3a7SDavid Howells * skb_to_sgvec - Fill a scatter-gather list from a socket buffer 2914716ea3a7SDavid Howells * @skb: Socket buffer containing the buffers to be mapped 2915716ea3a7SDavid Howells * @sg: The scatter-gather list to map into 2916716ea3a7SDavid Howells * @offset: The offset into the buffer's contents to start mapping 2917716ea3a7SDavid Howells * @len: Length of buffer space to be mapped 2918716ea3a7SDavid Howells * 2919716ea3a7SDavid Howells * Fill the specified scatter-gather list with mappings/pointers into a 2920716ea3a7SDavid Howells * region of the buffer space attached to a socket buffer. 2921716ea3a7SDavid Howells */ 292251c739d1SDavid S. Miller static int 292351c739d1SDavid S. Miller __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) 2924716ea3a7SDavid Howells { 29251a028e50SDavid S. Miller int start = skb_headlen(skb); 29261a028e50SDavid S. Miller int i, copy = start - offset; 2927fbb398a8SDavid S. Miller struct sk_buff *frag_iter; 2928716ea3a7SDavid Howells int elt = 0; 2929716ea3a7SDavid Howells 2930716ea3a7SDavid Howells if (copy > 0) { 2931716ea3a7SDavid Howells if (copy > len) 2932716ea3a7SDavid Howells copy = len; 2933642f1490SJens Axboe sg_set_buf(sg, skb->data + offset, copy); 2934716ea3a7SDavid Howells elt++; 2935716ea3a7SDavid Howells if ((len -= copy) == 0) 2936716ea3a7SDavid Howells return elt; 2937716ea3a7SDavid Howells offset += copy; 2938716ea3a7SDavid Howells } 2939716ea3a7SDavid Howells 2940716ea3a7SDavid Howells for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 29411a028e50SDavid S. Miller int end; 2942716ea3a7SDavid Howells 2943547b792cSIlpo Järvinen WARN_ON(start > offset + len); 29441a028e50SDavid S. Miller 29459e903e08SEric Dumazet end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]); 2946716ea3a7SDavid Howells if ((copy = end - offset) > 0) { 2947716ea3a7SDavid Howells skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 2948716ea3a7SDavid Howells 2949716ea3a7SDavid Howells if (copy > len) 2950716ea3a7SDavid Howells copy = len; 2951ea2ab693SIan Campbell sg_set_page(&sg[elt], skb_frag_page(frag), copy, 2952642f1490SJens Axboe frag->page_offset+offset-start); 2953716ea3a7SDavid Howells elt++; 2954716ea3a7SDavid Howells if (!(len -= copy)) 2955716ea3a7SDavid Howells return elt; 2956716ea3a7SDavid Howells offset += copy; 2957716ea3a7SDavid Howells } 29581a028e50SDavid S. Miller start = end; 2959716ea3a7SDavid Howells } 2960716ea3a7SDavid Howells 2961fbb398a8SDavid S. Miller skb_walk_frags(skb, frag_iter) { 29621a028e50SDavid S. Miller int end; 2963716ea3a7SDavid Howells 2964547b792cSIlpo Järvinen WARN_ON(start > offset + len); 29651a028e50SDavid S. Miller 2966fbb398a8SDavid S. Miller end = start + frag_iter->len; 2967716ea3a7SDavid Howells if ((copy = end - offset) > 0) { 2968716ea3a7SDavid Howells if (copy > len) 2969716ea3a7SDavid Howells copy = len; 2970fbb398a8SDavid S. Miller elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start, 297151c739d1SDavid S. Miller copy); 2972716ea3a7SDavid Howells if ((len -= copy) == 0) 2973716ea3a7SDavid Howells return elt; 2974716ea3a7SDavid Howells offset += copy; 2975716ea3a7SDavid Howells } 29761a028e50SDavid S. Miller start = end; 2977716ea3a7SDavid Howells } 2978716ea3a7SDavid Howells BUG_ON(len); 2979716ea3a7SDavid Howells return elt; 2980716ea3a7SDavid Howells } 2981716ea3a7SDavid Howells 298251c739d1SDavid S. Miller int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) 298351c739d1SDavid S. Miller { 298451c739d1SDavid S. Miller int nsg = __skb_to_sgvec(skb, sg, offset, len); 298551c739d1SDavid S. Miller 2986c46f2334SJens Axboe sg_mark_end(&sg[nsg - 1]); 298751c739d1SDavid S. Miller 298851c739d1SDavid S. Miller return nsg; 298951c739d1SDavid S. Miller } 2990b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_to_sgvec); 299151c739d1SDavid S. Miller 2992716ea3a7SDavid Howells /** 2993716ea3a7SDavid Howells * skb_cow_data - Check that a socket buffer's data buffers are writable 2994716ea3a7SDavid Howells * @skb: The socket buffer to check. 2995716ea3a7SDavid Howells * @tailbits: Amount of trailing space to be added 2996716ea3a7SDavid Howells * @trailer: Returned pointer to the skb where the @tailbits space begins 2997716ea3a7SDavid Howells * 2998716ea3a7SDavid Howells * Make sure that the data buffers attached to a socket buffer are 2999716ea3a7SDavid Howells * writable. If they are not, private copies are made of the data buffers 3000716ea3a7SDavid Howells * and the socket buffer is set to use these instead. 3001716ea3a7SDavid Howells * 3002716ea3a7SDavid Howells * If @tailbits is given, make sure that there is space to write @tailbits 3003716ea3a7SDavid Howells * bytes of data beyond current end of socket buffer. @trailer will be 3004716ea3a7SDavid Howells * set to point to the skb in which this space begins. 3005716ea3a7SDavid Howells * 3006716ea3a7SDavid Howells * The number of scatterlist elements required to completely map the 3007716ea3a7SDavid Howells * COW'd and extended socket buffer will be returned. 3008716ea3a7SDavid Howells */ 3009716ea3a7SDavid Howells int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) 3010716ea3a7SDavid Howells { 3011716ea3a7SDavid Howells int copyflag; 3012716ea3a7SDavid Howells int elt; 3013716ea3a7SDavid Howells struct sk_buff *skb1, **skb_p; 3014716ea3a7SDavid Howells 3015716ea3a7SDavid Howells /* If skb is cloned or its head is paged, reallocate 3016716ea3a7SDavid Howells * head pulling out all the pages (pages are considered not writable 3017716ea3a7SDavid Howells * at the moment even if they are anonymous). 3018716ea3a7SDavid Howells */ 3019716ea3a7SDavid Howells if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) && 3020716ea3a7SDavid Howells __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL) 3021716ea3a7SDavid Howells return -ENOMEM; 3022716ea3a7SDavid Howells 3023716ea3a7SDavid Howells /* Easy case. Most of packets will go this way. */ 302421dc3301SDavid S. Miller if (!skb_has_frag_list(skb)) { 3025716ea3a7SDavid Howells /* A little of trouble, not enough of space for trailer. 3026716ea3a7SDavid Howells * This should not happen, when stack is tuned to generate 3027716ea3a7SDavid Howells * good frames. OK, on miss we reallocate and reserve even more 3028716ea3a7SDavid Howells * space, 128 bytes is fair. */ 3029716ea3a7SDavid Howells 3030716ea3a7SDavid Howells if (skb_tailroom(skb) < tailbits && 3031716ea3a7SDavid Howells pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC)) 3032716ea3a7SDavid Howells return -ENOMEM; 3033716ea3a7SDavid Howells 3034716ea3a7SDavid Howells /* Voila! */ 3035716ea3a7SDavid Howells *trailer = skb; 3036716ea3a7SDavid Howells return 1; 3037716ea3a7SDavid Howells } 3038716ea3a7SDavid Howells 3039716ea3a7SDavid Howells /* Misery. We are in troubles, going to mincer fragments... */ 3040716ea3a7SDavid Howells 3041716ea3a7SDavid Howells elt = 1; 3042716ea3a7SDavid Howells skb_p = &skb_shinfo(skb)->frag_list; 3043716ea3a7SDavid Howells copyflag = 0; 3044716ea3a7SDavid Howells 3045716ea3a7SDavid Howells while ((skb1 = *skb_p) != NULL) { 3046716ea3a7SDavid Howells int ntail = 0; 3047716ea3a7SDavid Howells 3048716ea3a7SDavid Howells /* The fragment is partially pulled by someone, 3049716ea3a7SDavid Howells * this can happen on input. Copy it and everything 3050716ea3a7SDavid Howells * after it. */ 3051716ea3a7SDavid Howells 3052716ea3a7SDavid Howells if (skb_shared(skb1)) 3053716ea3a7SDavid Howells copyflag = 1; 3054716ea3a7SDavid Howells 3055716ea3a7SDavid Howells /* If the skb is the last, worry about trailer. */ 3056716ea3a7SDavid Howells 3057716ea3a7SDavid Howells if (skb1->next == NULL && tailbits) { 3058716ea3a7SDavid Howells if (skb_shinfo(skb1)->nr_frags || 305921dc3301SDavid S. Miller skb_has_frag_list(skb1) || 3060716ea3a7SDavid Howells skb_tailroom(skb1) < tailbits) 3061716ea3a7SDavid Howells ntail = tailbits + 128; 3062716ea3a7SDavid Howells } 3063716ea3a7SDavid Howells 3064716ea3a7SDavid Howells if (copyflag || 3065716ea3a7SDavid Howells skb_cloned(skb1) || 3066716ea3a7SDavid Howells ntail || 3067716ea3a7SDavid Howells skb_shinfo(skb1)->nr_frags || 306821dc3301SDavid S. Miller skb_has_frag_list(skb1)) { 3069716ea3a7SDavid Howells struct sk_buff *skb2; 3070716ea3a7SDavid Howells 3071716ea3a7SDavid Howells /* Fuck, we are miserable poor guys... */ 3072716ea3a7SDavid Howells if (ntail == 0) 3073716ea3a7SDavid Howells skb2 = skb_copy(skb1, GFP_ATOMIC); 3074716ea3a7SDavid Howells else 3075716ea3a7SDavid Howells skb2 = skb_copy_expand(skb1, 3076716ea3a7SDavid Howells skb_headroom(skb1), 3077716ea3a7SDavid Howells ntail, 3078716ea3a7SDavid Howells GFP_ATOMIC); 3079716ea3a7SDavid Howells if (unlikely(skb2 == NULL)) 3080716ea3a7SDavid Howells return -ENOMEM; 3081716ea3a7SDavid Howells 3082716ea3a7SDavid Howells if (skb1->sk) 3083716ea3a7SDavid Howells skb_set_owner_w(skb2, skb1->sk); 3084716ea3a7SDavid Howells 3085716ea3a7SDavid Howells /* Looking around. Are we still alive? 3086716ea3a7SDavid Howells * OK, link new skb, drop old one */ 3087716ea3a7SDavid Howells 3088716ea3a7SDavid Howells skb2->next = skb1->next; 3089716ea3a7SDavid Howells *skb_p = skb2; 3090716ea3a7SDavid Howells kfree_skb(skb1); 3091716ea3a7SDavid Howells skb1 = skb2; 3092716ea3a7SDavid Howells } 3093716ea3a7SDavid Howells elt++; 3094716ea3a7SDavid Howells *trailer = skb1; 3095716ea3a7SDavid Howells skb_p = &skb1->next; 3096716ea3a7SDavid Howells } 3097716ea3a7SDavid Howells 3098716ea3a7SDavid Howells return elt; 3099716ea3a7SDavid Howells } 3100b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_cow_data); 3101716ea3a7SDavid Howells 3102b1faf566SEric Dumazet static void sock_rmem_free(struct sk_buff *skb) 3103b1faf566SEric Dumazet { 3104b1faf566SEric Dumazet struct sock *sk = skb->sk; 3105b1faf566SEric Dumazet 3106b1faf566SEric Dumazet atomic_sub(skb->truesize, &sk->sk_rmem_alloc); 3107b1faf566SEric Dumazet } 3108b1faf566SEric Dumazet 3109b1faf566SEric Dumazet /* 3110b1faf566SEric Dumazet * Note: We dont mem charge error packets (no sk_forward_alloc changes) 3111b1faf566SEric Dumazet */ 3112b1faf566SEric Dumazet int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb) 3113b1faf566SEric Dumazet { 3114b1faf566SEric Dumazet if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >= 3115b1faf566SEric Dumazet (unsigned)sk->sk_rcvbuf) 3116b1faf566SEric Dumazet return -ENOMEM; 3117b1faf566SEric Dumazet 3118b1faf566SEric Dumazet skb_orphan(skb); 3119b1faf566SEric Dumazet skb->sk = sk; 3120b1faf566SEric Dumazet skb->destructor = sock_rmem_free; 3121b1faf566SEric Dumazet atomic_add(skb->truesize, &sk->sk_rmem_alloc); 3122b1faf566SEric Dumazet 3123abb57ea4SEric Dumazet /* before exiting rcu section, make sure dst is refcounted */ 3124abb57ea4SEric Dumazet skb_dst_force(skb); 3125abb57ea4SEric Dumazet 3126b1faf566SEric Dumazet skb_queue_tail(&sk->sk_error_queue, skb); 3127b1faf566SEric Dumazet if (!sock_flag(sk, SOCK_DEAD)) 3128b1faf566SEric Dumazet sk->sk_data_ready(sk, skb->len); 3129b1faf566SEric Dumazet return 0; 3130b1faf566SEric Dumazet } 3131b1faf566SEric Dumazet EXPORT_SYMBOL(sock_queue_err_skb); 3132b1faf566SEric Dumazet 3133ac45f602SPatrick Ohly void skb_tstamp_tx(struct sk_buff *orig_skb, 3134ac45f602SPatrick Ohly struct skb_shared_hwtstamps *hwtstamps) 3135ac45f602SPatrick Ohly { 3136ac45f602SPatrick Ohly struct sock *sk = orig_skb->sk; 3137ac45f602SPatrick Ohly struct sock_exterr_skb *serr; 3138ac45f602SPatrick Ohly struct sk_buff *skb; 3139ac45f602SPatrick Ohly int err; 3140ac45f602SPatrick Ohly 3141ac45f602SPatrick Ohly if (!sk) 3142ac45f602SPatrick Ohly return; 3143ac45f602SPatrick Ohly 3144ac45f602SPatrick Ohly skb = skb_clone(orig_skb, GFP_ATOMIC); 3145ac45f602SPatrick Ohly if (!skb) 3146ac45f602SPatrick Ohly return; 3147ac45f602SPatrick Ohly 3148ac45f602SPatrick Ohly if (hwtstamps) { 3149ac45f602SPatrick Ohly *skb_hwtstamps(skb) = 3150ac45f602SPatrick Ohly *hwtstamps; 3151ac45f602SPatrick Ohly } else { 3152ac45f602SPatrick Ohly /* 3153ac45f602SPatrick Ohly * no hardware time stamps available, 31542244d07bSOliver Hartkopp * so keep the shared tx_flags and only 3155ac45f602SPatrick Ohly * store software time stamp 3156ac45f602SPatrick Ohly */ 3157ac45f602SPatrick Ohly skb->tstamp = ktime_get_real(); 3158ac45f602SPatrick Ohly } 3159ac45f602SPatrick Ohly 3160ac45f602SPatrick Ohly serr = SKB_EXT_ERR(skb); 3161ac45f602SPatrick Ohly memset(serr, 0, sizeof(*serr)); 3162ac45f602SPatrick Ohly serr->ee.ee_errno = ENOMSG; 3163ac45f602SPatrick Ohly serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; 316429030374SEric Dumazet 3165ac45f602SPatrick Ohly err = sock_queue_err_skb(sk, skb); 316629030374SEric Dumazet 3167ac45f602SPatrick Ohly if (err) 3168ac45f602SPatrick Ohly kfree_skb(skb); 3169ac45f602SPatrick Ohly } 3170ac45f602SPatrick Ohly EXPORT_SYMBOL_GPL(skb_tstamp_tx); 3171ac45f602SPatrick Ohly 3172ac45f602SPatrick Ohly 3173f35d9d8aSRusty Russell /** 3174f35d9d8aSRusty Russell * skb_partial_csum_set - set up and verify partial csum values for packet 3175f35d9d8aSRusty Russell * @skb: the skb to set 3176f35d9d8aSRusty Russell * @start: the number of bytes after skb->data to start checksumming. 3177f35d9d8aSRusty Russell * @off: the offset from start to place the checksum. 3178f35d9d8aSRusty Russell * 3179f35d9d8aSRusty Russell * For untrusted partially-checksummed packets, we need to make sure the values 3180f35d9d8aSRusty Russell * for skb->csum_start and skb->csum_offset are valid so we don't oops. 3181f35d9d8aSRusty Russell * 3182f35d9d8aSRusty Russell * This function checks and sets those values and skb->ip_summed: if this 3183f35d9d8aSRusty Russell * returns false you should drop the packet. 3184f35d9d8aSRusty Russell */ 3185f35d9d8aSRusty Russell bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off) 3186f35d9d8aSRusty Russell { 31875ff8dda3SHerbert Xu if (unlikely(start > skb_headlen(skb)) || 31885ff8dda3SHerbert Xu unlikely((int)start + off > skb_headlen(skb) - 2)) { 3189f35d9d8aSRusty Russell if (net_ratelimit()) 3190f35d9d8aSRusty Russell printk(KERN_WARNING 3191f35d9d8aSRusty Russell "bad partial csum: csum=%u/%u len=%u\n", 31925ff8dda3SHerbert Xu start, off, skb_headlen(skb)); 3193f35d9d8aSRusty Russell return false; 3194f35d9d8aSRusty Russell } 3195f35d9d8aSRusty Russell skb->ip_summed = CHECKSUM_PARTIAL; 3196f35d9d8aSRusty Russell skb->csum_start = skb_headroom(skb) + start; 3197f35d9d8aSRusty Russell skb->csum_offset = off; 3198f35d9d8aSRusty Russell return true; 3199f35d9d8aSRusty Russell } 3200b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_partial_csum_set); 3201f35d9d8aSRusty Russell 32024497b076SBen Hutchings void __skb_warn_lro_forwarding(const struct sk_buff *skb) 32034497b076SBen Hutchings { 32044497b076SBen Hutchings if (net_ratelimit()) 32054497b076SBen Hutchings pr_warning("%s: received packets cannot be forwarded" 32064497b076SBen Hutchings " while LRO is enabled\n", skb->dev->name); 32074497b076SBen Hutchings } 32084497b076SBen Hutchings EXPORT_SYMBOL(__skb_warn_lro_forwarding); 3209