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> 421da177e4SLinus Torvalds #include <linux/mm.h> 431da177e4SLinus Torvalds #include <linux/interrupt.h> 441da177e4SLinus Torvalds #include <linux/in.h> 451da177e4SLinus Torvalds #include <linux/inet.h> 461da177e4SLinus Torvalds #include <linux/slab.h> 471da177e4SLinus Torvalds #include <linux/netdevice.h> 481da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 491da177e4SLinus Torvalds #include <net/pkt_sched.h> 501da177e4SLinus Torvalds #endif 511da177e4SLinus Torvalds #include <linux/string.h> 521da177e4SLinus Torvalds #include <linux/skbuff.h> 539c55e01cSJens Axboe #include <linux/splice.h> 541da177e4SLinus Torvalds #include <linux/cache.h> 551da177e4SLinus Torvalds #include <linux/rtnetlink.h> 561da177e4SLinus Torvalds #include <linux/init.h> 57716ea3a7SDavid Howells #include <linux/scatterlist.h> 58ac45f602SPatrick Ohly #include <linux/errqueue.h> 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds #include <net/protocol.h> 611da177e4SLinus Torvalds #include <net/dst.h> 621da177e4SLinus Torvalds #include <net/sock.h> 631da177e4SLinus Torvalds #include <net/checksum.h> 641da177e4SLinus Torvalds #include <net/xfrm.h> 651da177e4SLinus Torvalds 661da177e4SLinus Torvalds #include <asm/uaccess.h> 671da177e4SLinus Torvalds #include <asm/system.h> 681da177e4SLinus Torvalds 69a1f8e7f7SAl Viro #include "kmap_skb.h" 70a1f8e7f7SAl Viro 71e18b890bSChristoph Lameter static struct kmem_cache *skbuff_head_cache __read_mostly; 72e18b890bSChristoph Lameter static struct kmem_cache *skbuff_fclone_cache __read_mostly; 731da177e4SLinus Torvalds 749c55e01cSJens Axboe static void sock_pipe_buf_release(struct pipe_inode_info *pipe, 759c55e01cSJens Axboe struct pipe_buffer *buf) 769c55e01cSJens Axboe { 778b9d3728SJarek Poplawski put_page(buf->page); 789c55e01cSJens Axboe } 799c55e01cSJens Axboe 809c55e01cSJens Axboe static void sock_pipe_buf_get(struct pipe_inode_info *pipe, 819c55e01cSJens Axboe struct pipe_buffer *buf) 829c55e01cSJens Axboe { 838b9d3728SJarek Poplawski get_page(buf->page); 849c55e01cSJens Axboe } 859c55e01cSJens Axboe 869c55e01cSJens Axboe static int sock_pipe_buf_steal(struct pipe_inode_info *pipe, 879c55e01cSJens Axboe struct pipe_buffer *buf) 889c55e01cSJens Axboe { 899c55e01cSJens Axboe return 1; 909c55e01cSJens Axboe } 919c55e01cSJens Axboe 929c55e01cSJens Axboe 939c55e01cSJens Axboe /* Pipe buffer operations for a socket. */ 949c55e01cSJens Axboe static struct pipe_buf_operations sock_pipe_buf_ops = { 959c55e01cSJens Axboe .can_merge = 0, 969c55e01cSJens Axboe .map = generic_pipe_buf_map, 979c55e01cSJens Axboe .unmap = generic_pipe_buf_unmap, 989c55e01cSJens Axboe .confirm = generic_pipe_buf_confirm, 999c55e01cSJens Axboe .release = sock_pipe_buf_release, 1009c55e01cSJens Axboe .steal = sock_pipe_buf_steal, 1019c55e01cSJens Axboe .get = sock_pipe_buf_get, 1029c55e01cSJens Axboe }; 1039c55e01cSJens Axboe 1041da177e4SLinus Torvalds /* 1051da177e4SLinus Torvalds * Keep out-of-line to prevent kernel bloat. 1061da177e4SLinus Torvalds * __builtin_return_address is not used because it is not always 1071da177e4SLinus Torvalds * reliable. 1081da177e4SLinus Torvalds */ 1091da177e4SLinus Torvalds 1101da177e4SLinus Torvalds /** 1111da177e4SLinus Torvalds * skb_over_panic - private function 1121da177e4SLinus Torvalds * @skb: buffer 1131da177e4SLinus Torvalds * @sz: size 1141da177e4SLinus Torvalds * @here: address 1151da177e4SLinus Torvalds * 1161da177e4SLinus Torvalds * Out of line support code for skb_put(). Not user callable. 1171da177e4SLinus Torvalds */ 1181da177e4SLinus Torvalds void skb_over_panic(struct sk_buff *skb, int sz, void *here) 1191da177e4SLinus Torvalds { 12026095455SPatrick McHardy printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " 1214305b541SArnaldo Carvalho de Melo "data:%p tail:%#lx end:%#lx dev:%s\n", 12227a884dcSArnaldo Carvalho de Melo here, skb->len, sz, skb->head, skb->data, 1234305b541SArnaldo Carvalho de Melo (unsigned long)skb->tail, (unsigned long)skb->end, 12426095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1251da177e4SLinus Torvalds BUG(); 1261da177e4SLinus Torvalds } 127b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_over_panic); 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds /** 1301da177e4SLinus Torvalds * skb_under_panic - private function 1311da177e4SLinus Torvalds * @skb: buffer 1321da177e4SLinus Torvalds * @sz: size 1331da177e4SLinus Torvalds * @here: address 1341da177e4SLinus Torvalds * 1351da177e4SLinus Torvalds * Out of line support code for skb_push(). Not user callable. 1361da177e4SLinus Torvalds */ 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds void skb_under_panic(struct sk_buff *skb, int sz, void *here) 1391da177e4SLinus Torvalds { 14026095455SPatrick McHardy printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " 1414305b541SArnaldo Carvalho de Melo "data:%p tail:%#lx end:%#lx dev:%s\n", 14227a884dcSArnaldo Carvalho de Melo here, skb->len, sz, skb->head, skb->data, 1434305b541SArnaldo Carvalho de Melo (unsigned long)skb->tail, (unsigned long)skb->end, 14426095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1451da177e4SLinus Torvalds BUG(); 1461da177e4SLinus Torvalds } 147b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_under_panic); 1481da177e4SLinus Torvalds 149dc6de336SDavid S. Miller void skb_truesize_bug(struct sk_buff *skb) 150dc6de336SDavid S. Miller { 1518f480c0eSArjan van de Ven WARN(net_ratelimit(), KERN_ERR "SKB BUG: Invalid truesize (%u) " 152dc6de336SDavid S. Miller "len=%u, sizeof(sk_buff)=%Zd\n", 153dc6de336SDavid S. Miller skb->truesize, skb->len, sizeof(struct sk_buff)); 154dc6de336SDavid S. Miller } 155dc6de336SDavid S. Miller EXPORT_SYMBOL(skb_truesize_bug); 156dc6de336SDavid S. Miller 1571da177e4SLinus Torvalds /* Allocate a new skbuff. We do this ourselves so we can fill in a few 1581da177e4SLinus Torvalds * 'private' fields and also do memory statistics to find all the 1591da177e4SLinus Torvalds * [BEEP] leaks. 1601da177e4SLinus Torvalds * 1611da177e4SLinus Torvalds */ 1621da177e4SLinus Torvalds 1631da177e4SLinus Torvalds /** 164d179cd12SDavid S. Miller * __alloc_skb - allocate a network buffer 1651da177e4SLinus Torvalds * @size: size to allocate 1661da177e4SLinus Torvalds * @gfp_mask: allocation mask 167c83c2486SRandy Dunlap * @fclone: allocate from fclone cache instead of head cache 168c83c2486SRandy Dunlap * and allocate a cloned (child) skb 169b30973f8SChristoph Hellwig * @node: numa node to allocate memory on 1701da177e4SLinus Torvalds * 1711da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and a 1721da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 1731da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 1741da177e4SLinus Torvalds * 1751da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1761da177e4SLinus Torvalds * %GFP_ATOMIC. 1771da177e4SLinus Torvalds */ 178dd0fc66fSAl Viro struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, 179b30973f8SChristoph Hellwig int fclone, int node) 1801da177e4SLinus Torvalds { 181e18b890bSChristoph Lameter struct kmem_cache *cache; 1824947d3efSBenjamin LaHaise struct skb_shared_info *shinfo; 1831da177e4SLinus Torvalds struct sk_buff *skb; 1841da177e4SLinus Torvalds u8 *data; 1851da177e4SLinus Torvalds 1868798b3fbSHerbert Xu cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; 1878798b3fbSHerbert Xu 1881da177e4SLinus Torvalds /* Get the HEAD */ 189b30973f8SChristoph Hellwig skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); 1901da177e4SLinus Torvalds if (!skb) 1911da177e4SLinus Torvalds goto out; 1921da177e4SLinus Torvalds 1931da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 194b30973f8SChristoph Hellwig data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info), 195b30973f8SChristoph Hellwig gfp_mask, node); 1961da177e4SLinus Torvalds if (!data) 1971da177e4SLinus Torvalds goto nodata; 1981da177e4SLinus Torvalds 199ca0605a7SArnaldo Carvalho de Melo /* 200c8005785SJohannes Berg * Only clear those fields we need to clear, not those that we will 201c8005785SJohannes Berg * actually initialise below. Hence, don't put any more fields after 202c8005785SJohannes Berg * the tail pointer in struct sk_buff! 203ca0605a7SArnaldo Carvalho de Melo */ 204ca0605a7SArnaldo Carvalho de Melo memset(skb, 0, offsetof(struct sk_buff, tail)); 2051da177e4SLinus Torvalds skb->truesize = size + sizeof(struct sk_buff); 2061da177e4SLinus Torvalds atomic_set(&skb->users, 1); 2071da177e4SLinus Torvalds skb->head = data; 2081da177e4SLinus Torvalds skb->data = data; 20927a884dcSArnaldo Carvalho de Melo skb_reset_tail_pointer(skb); 2104305b541SArnaldo Carvalho de Melo skb->end = skb->tail + size; 2114947d3efSBenjamin LaHaise /* make sure we initialize shinfo sequentially */ 2124947d3efSBenjamin LaHaise shinfo = skb_shinfo(skb); 2134947d3efSBenjamin LaHaise atomic_set(&shinfo->dataref, 1); 2144947d3efSBenjamin LaHaise shinfo->nr_frags = 0; 2157967168cSHerbert Xu shinfo->gso_size = 0; 2167967168cSHerbert Xu shinfo->gso_segs = 0; 2177967168cSHerbert Xu shinfo->gso_type = 0; 2184947d3efSBenjamin LaHaise shinfo->ip6_frag_id = 0; 219ac45f602SPatrick Ohly shinfo->tx_flags.flags = 0; 2204947d3efSBenjamin LaHaise shinfo->frag_list = NULL; 221ac45f602SPatrick Ohly memset(&shinfo->hwtstamps, 0, sizeof(shinfo->hwtstamps)); 2224947d3efSBenjamin LaHaise 223d179cd12SDavid S. Miller if (fclone) { 224d179cd12SDavid S. Miller struct sk_buff *child = skb + 1; 225d179cd12SDavid S. Miller atomic_t *fclone_ref = (atomic_t *) (child + 1); 2261da177e4SLinus Torvalds 227d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_ORIG; 228d179cd12SDavid S. Miller atomic_set(fclone_ref, 1); 229d179cd12SDavid S. Miller 230d179cd12SDavid S. Miller child->fclone = SKB_FCLONE_UNAVAILABLE; 231d179cd12SDavid S. Miller } 2321da177e4SLinus Torvalds out: 2331da177e4SLinus Torvalds return skb; 2341da177e4SLinus Torvalds nodata: 2358798b3fbSHerbert Xu kmem_cache_free(cache, skb); 2361da177e4SLinus Torvalds skb = NULL; 2371da177e4SLinus Torvalds goto out; 2381da177e4SLinus Torvalds } 239b4ac530fSDavid S. Miller EXPORT_SYMBOL(__alloc_skb); 2401da177e4SLinus Torvalds 2411da177e4SLinus Torvalds /** 2428af27456SChristoph Hellwig * __netdev_alloc_skb - allocate an skbuff for rx on a specific device 2438af27456SChristoph Hellwig * @dev: network device to receive on 2448af27456SChristoph Hellwig * @length: length to allocate 2458af27456SChristoph Hellwig * @gfp_mask: get_free_pages mask, passed to alloc_skb 2468af27456SChristoph Hellwig * 2478af27456SChristoph Hellwig * Allocate a new &sk_buff and assign it a usage count of one. The 2488af27456SChristoph Hellwig * buffer has unspecified headroom built in. Users should allocate 2498af27456SChristoph Hellwig * the headroom they think they need without accounting for the 2508af27456SChristoph Hellwig * built in space. The built in space is used for optimisations. 2518af27456SChristoph Hellwig * 2528af27456SChristoph Hellwig * %NULL is returned if there is no free memory. 2538af27456SChristoph Hellwig */ 2548af27456SChristoph Hellwig struct sk_buff *__netdev_alloc_skb(struct net_device *dev, 2558af27456SChristoph Hellwig unsigned int length, gfp_t gfp_mask) 2568af27456SChristoph Hellwig { 25743cb76d9SGreg Kroah-Hartman int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1; 2588af27456SChristoph Hellwig struct sk_buff *skb; 2598af27456SChristoph Hellwig 260b30973f8SChristoph Hellwig skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node); 2617b2e497aSChristoph Hellwig if (likely(skb)) { 2628af27456SChristoph Hellwig skb_reserve(skb, NET_SKB_PAD); 2637b2e497aSChristoph Hellwig skb->dev = dev; 2647b2e497aSChristoph Hellwig } 2658af27456SChristoph Hellwig return skb; 2668af27456SChristoph Hellwig } 267b4ac530fSDavid S. Miller EXPORT_SYMBOL(__netdev_alloc_skb); 2681da177e4SLinus Torvalds 269654bed16SPeter Zijlstra struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask) 270654bed16SPeter Zijlstra { 271654bed16SPeter Zijlstra int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1; 272654bed16SPeter Zijlstra struct page *page; 273654bed16SPeter Zijlstra 274654bed16SPeter Zijlstra page = alloc_pages_node(node, gfp_mask, 0); 275654bed16SPeter Zijlstra return page; 276654bed16SPeter Zijlstra } 277654bed16SPeter Zijlstra EXPORT_SYMBOL(__netdev_alloc_page); 278654bed16SPeter Zijlstra 279654bed16SPeter Zijlstra void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, 280654bed16SPeter Zijlstra int size) 281654bed16SPeter Zijlstra { 282654bed16SPeter Zijlstra skb_fill_page_desc(skb, i, page, off, size); 283654bed16SPeter Zijlstra skb->len += size; 284654bed16SPeter Zijlstra skb->data_len += size; 285654bed16SPeter Zijlstra skb->truesize += size; 286654bed16SPeter Zijlstra } 287654bed16SPeter Zijlstra EXPORT_SYMBOL(skb_add_rx_frag); 288654bed16SPeter Zijlstra 289f58518e6SIlpo Järvinen /** 290f58518e6SIlpo Järvinen * dev_alloc_skb - allocate an skbuff for receiving 291f58518e6SIlpo Järvinen * @length: length to allocate 292f58518e6SIlpo Järvinen * 293f58518e6SIlpo Järvinen * Allocate a new &sk_buff and assign it a usage count of one. The 294f58518e6SIlpo Järvinen * buffer has unspecified headroom built in. Users should allocate 295f58518e6SIlpo Järvinen * the headroom they think they need without accounting for the 296f58518e6SIlpo Järvinen * built in space. The built in space is used for optimisations. 297f58518e6SIlpo Järvinen * 298f58518e6SIlpo Järvinen * %NULL is returned if there is no free memory. Although this function 299f58518e6SIlpo Järvinen * allocates memory it can be called from an interrupt. 300f58518e6SIlpo Järvinen */ 301f58518e6SIlpo Järvinen struct sk_buff *dev_alloc_skb(unsigned int length) 302f58518e6SIlpo Järvinen { 3031483b874SDenys Vlasenko /* 3041483b874SDenys Vlasenko * There is more code here than it seems: 305a0f55e0eSDavid S. Miller * __dev_alloc_skb is an inline 3061483b874SDenys Vlasenko */ 307f58518e6SIlpo Järvinen return __dev_alloc_skb(length, GFP_ATOMIC); 308f58518e6SIlpo Järvinen } 309f58518e6SIlpo Järvinen EXPORT_SYMBOL(dev_alloc_skb); 310f58518e6SIlpo Järvinen 31127b437c8SHerbert Xu static void skb_drop_list(struct sk_buff **listp) 3121da177e4SLinus Torvalds { 31327b437c8SHerbert Xu struct sk_buff *list = *listp; 3141da177e4SLinus Torvalds 31527b437c8SHerbert Xu *listp = NULL; 3161da177e4SLinus Torvalds 3171da177e4SLinus Torvalds do { 3181da177e4SLinus Torvalds struct sk_buff *this = list; 3191da177e4SLinus Torvalds list = list->next; 3201da177e4SLinus Torvalds kfree_skb(this); 3211da177e4SLinus Torvalds } while (list); 3221da177e4SLinus Torvalds } 3231da177e4SLinus Torvalds 32427b437c8SHerbert Xu static inline void skb_drop_fraglist(struct sk_buff *skb) 32527b437c8SHerbert Xu { 32627b437c8SHerbert Xu skb_drop_list(&skb_shinfo(skb)->frag_list); 32727b437c8SHerbert Xu } 32827b437c8SHerbert Xu 3291da177e4SLinus Torvalds static void skb_clone_fraglist(struct sk_buff *skb) 3301da177e4SLinus Torvalds { 3311da177e4SLinus Torvalds struct sk_buff *list; 3321da177e4SLinus Torvalds 3331da177e4SLinus Torvalds for (list = skb_shinfo(skb)->frag_list; list; list = list->next) 3341da177e4SLinus Torvalds skb_get(list); 3351da177e4SLinus Torvalds } 3361da177e4SLinus Torvalds 3375bba1712SAdrian Bunk static void skb_release_data(struct sk_buff *skb) 3381da177e4SLinus Torvalds { 3391da177e4SLinus Torvalds if (!skb->cloned || 3401da177e4SLinus Torvalds !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, 3411da177e4SLinus Torvalds &skb_shinfo(skb)->dataref)) { 3421da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 3431da177e4SLinus Torvalds int i; 3441da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 3451da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 3461da177e4SLinus Torvalds } 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 3491da177e4SLinus Torvalds skb_drop_fraglist(skb); 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds kfree(skb->head); 3521da177e4SLinus Torvalds } 3531da177e4SLinus Torvalds } 3541da177e4SLinus Torvalds 3551da177e4SLinus Torvalds /* 3561da177e4SLinus Torvalds * Free an skbuff by memory without cleaning the state. 3571da177e4SLinus Torvalds */ 3582d4baff8SHerbert Xu static void kfree_skbmem(struct sk_buff *skb) 3591da177e4SLinus Torvalds { 360d179cd12SDavid S. Miller struct sk_buff *other; 361d179cd12SDavid S. Miller atomic_t *fclone_ref; 362d179cd12SDavid S. Miller 363d179cd12SDavid S. Miller switch (skb->fclone) { 364d179cd12SDavid S. Miller case SKB_FCLONE_UNAVAILABLE: 3651da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 366d179cd12SDavid S. Miller break; 367d179cd12SDavid S. Miller 368d179cd12SDavid S. Miller case SKB_FCLONE_ORIG: 369d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 2); 370d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 371d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, skb); 372d179cd12SDavid S. Miller break; 373d179cd12SDavid S. Miller 374d179cd12SDavid S. Miller case SKB_FCLONE_CLONE: 375d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 1); 376d179cd12SDavid S. Miller other = skb - 1; 377d179cd12SDavid S. Miller 378d179cd12SDavid S. Miller /* The clone portion is available for 379d179cd12SDavid S. Miller * fast-cloning again. 380d179cd12SDavid S. Miller */ 381d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_UNAVAILABLE; 382d179cd12SDavid S. Miller 383d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 384d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, other); 385d179cd12SDavid S. Miller break; 3863ff50b79SStephen Hemminger } 3871da177e4SLinus Torvalds } 3881da177e4SLinus Torvalds 38904a4bb55SLennert Buytenhek static void skb_release_head_state(struct sk_buff *skb) 3901da177e4SLinus Torvalds { 3911da177e4SLinus Torvalds dst_release(skb->dst); 3921da177e4SLinus Torvalds #ifdef CONFIG_XFRM 3931da177e4SLinus Torvalds secpath_put(skb->sp); 3941da177e4SLinus Torvalds #endif 3951da177e4SLinus Torvalds if (skb->destructor) { 3969c2b3328SStephen Hemminger WARN_ON(in_irq()); 3971da177e4SLinus Torvalds skb->destructor(skb); 3981da177e4SLinus Torvalds } 3999fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4005f79e0f9SYasuyuki Kozakai nf_conntrack_put(skb->nfct); 4019fb9cbb1SYasuyuki Kozakai nf_conntrack_put_reasm(skb->nfct_reasm); 4029fb9cbb1SYasuyuki Kozakai #endif 4031da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 4041da177e4SLinus Torvalds nf_bridge_put(skb->nf_bridge); 4051da177e4SLinus Torvalds #endif 4061da177e4SLinus Torvalds /* XXX: IS this still necessary? - JHS */ 4071da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 4081da177e4SLinus Torvalds skb->tc_index = 0; 4091da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 4101da177e4SLinus Torvalds skb->tc_verd = 0; 4111da177e4SLinus Torvalds #endif 4121da177e4SLinus Torvalds #endif 41304a4bb55SLennert Buytenhek } 41404a4bb55SLennert Buytenhek 41504a4bb55SLennert Buytenhek /* Free everything but the sk_buff shell. */ 41604a4bb55SLennert Buytenhek static void skb_release_all(struct sk_buff *skb) 41704a4bb55SLennert Buytenhek { 41804a4bb55SLennert Buytenhek skb_release_head_state(skb); 4192d4baff8SHerbert Xu skb_release_data(skb); 4202d4baff8SHerbert Xu } 4211da177e4SLinus Torvalds 4222d4baff8SHerbert Xu /** 4232d4baff8SHerbert Xu * __kfree_skb - private function 4242d4baff8SHerbert Xu * @skb: buffer 4252d4baff8SHerbert Xu * 4262d4baff8SHerbert Xu * Free an sk_buff. Release anything attached to the buffer. 4272d4baff8SHerbert Xu * Clean the state. This is an internal helper function. Users should 4282d4baff8SHerbert Xu * always call kfree_skb 4292d4baff8SHerbert Xu */ 4302d4baff8SHerbert Xu 4312d4baff8SHerbert Xu void __kfree_skb(struct sk_buff *skb) 4322d4baff8SHerbert Xu { 4332d4baff8SHerbert Xu skb_release_all(skb); 4341da177e4SLinus Torvalds kfree_skbmem(skb); 4351da177e4SLinus Torvalds } 436b4ac530fSDavid S. Miller EXPORT_SYMBOL(__kfree_skb); 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds /** 439231d06aeSJörn Engel * kfree_skb - free an sk_buff 440231d06aeSJörn Engel * @skb: buffer to free 441231d06aeSJörn Engel * 442231d06aeSJörn Engel * Drop a reference to the buffer and free it if the usage count has 443231d06aeSJörn Engel * hit zero. 444231d06aeSJörn Engel */ 445231d06aeSJörn Engel void kfree_skb(struct sk_buff *skb) 446231d06aeSJörn Engel { 447231d06aeSJörn Engel if (unlikely(!skb)) 448231d06aeSJörn Engel return; 449231d06aeSJörn Engel if (likely(atomic_read(&skb->users) == 1)) 450231d06aeSJörn Engel smp_rmb(); 451231d06aeSJörn Engel else if (likely(!atomic_dec_and_test(&skb->users))) 452231d06aeSJörn Engel return; 453231d06aeSJörn Engel __kfree_skb(skb); 454231d06aeSJörn Engel } 455b4ac530fSDavid S. Miller EXPORT_SYMBOL(kfree_skb); 456231d06aeSJörn Engel 457d1a203eaSStephen Hemminger /** 458d1a203eaSStephen Hemminger * skb_recycle_check - check if skb can be reused for receive 459d1a203eaSStephen Hemminger * @skb: buffer 460d1a203eaSStephen Hemminger * @skb_size: minimum receive buffer size 461d1a203eaSStephen Hemminger * 462d1a203eaSStephen Hemminger * Checks that the skb passed in is not shared or cloned, and 463d1a203eaSStephen Hemminger * that it is linear and its head portion at least as large as 464d1a203eaSStephen Hemminger * skb_size so that it can be recycled as a receive buffer. 465d1a203eaSStephen Hemminger * If these conditions are met, this function does any necessary 466d1a203eaSStephen Hemminger * reference count dropping and cleans up the skbuff as if it 467d1a203eaSStephen Hemminger * just came from __alloc_skb(). 468d1a203eaSStephen Hemminger */ 46904a4bb55SLennert Buytenhek int skb_recycle_check(struct sk_buff *skb, int skb_size) 47004a4bb55SLennert Buytenhek { 47104a4bb55SLennert Buytenhek struct skb_shared_info *shinfo; 47204a4bb55SLennert Buytenhek 47304a4bb55SLennert Buytenhek if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE) 47404a4bb55SLennert Buytenhek return 0; 47504a4bb55SLennert Buytenhek 47604a4bb55SLennert Buytenhek skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD); 47704a4bb55SLennert Buytenhek if (skb_end_pointer(skb) - skb->head < skb_size) 47804a4bb55SLennert Buytenhek return 0; 47904a4bb55SLennert Buytenhek 48004a4bb55SLennert Buytenhek if (skb_shared(skb) || skb_cloned(skb)) 48104a4bb55SLennert Buytenhek return 0; 48204a4bb55SLennert Buytenhek 48304a4bb55SLennert Buytenhek skb_release_head_state(skb); 48404a4bb55SLennert Buytenhek shinfo = skb_shinfo(skb); 48504a4bb55SLennert Buytenhek atomic_set(&shinfo->dataref, 1); 48604a4bb55SLennert Buytenhek shinfo->nr_frags = 0; 48704a4bb55SLennert Buytenhek shinfo->gso_size = 0; 48804a4bb55SLennert Buytenhek shinfo->gso_segs = 0; 48904a4bb55SLennert Buytenhek shinfo->gso_type = 0; 49004a4bb55SLennert Buytenhek shinfo->ip6_frag_id = 0; 49104a4bb55SLennert Buytenhek shinfo->frag_list = NULL; 49204a4bb55SLennert Buytenhek 49304a4bb55SLennert Buytenhek memset(skb, 0, offsetof(struct sk_buff, tail)); 49404a4bb55SLennert Buytenhek skb->data = skb->head + NET_SKB_PAD; 4955cd33db2SLennert Buytenhek skb_reset_tail_pointer(skb); 49604a4bb55SLennert Buytenhek 49704a4bb55SLennert Buytenhek return 1; 49804a4bb55SLennert Buytenhek } 49904a4bb55SLennert Buytenhek EXPORT_SYMBOL(skb_recycle_check); 50004a4bb55SLennert Buytenhek 501dec18810SHerbert Xu static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 502dec18810SHerbert Xu { 503dec18810SHerbert Xu new->tstamp = old->tstamp; 504dec18810SHerbert Xu new->dev = old->dev; 505dec18810SHerbert Xu new->transport_header = old->transport_header; 506dec18810SHerbert Xu new->network_header = old->network_header; 507dec18810SHerbert Xu new->mac_header = old->mac_header; 508dec18810SHerbert Xu new->dst = dst_clone(old->dst); 509def8b4faSAlexey Dobriyan #ifdef CONFIG_XFRM 510dec18810SHerbert Xu new->sp = secpath_get(old->sp); 511dec18810SHerbert Xu #endif 512dec18810SHerbert Xu memcpy(new->cb, old->cb, sizeof(old->cb)); 513dec18810SHerbert Xu new->csum_start = old->csum_start; 514dec18810SHerbert Xu new->csum_offset = old->csum_offset; 515dec18810SHerbert Xu new->local_df = old->local_df; 516dec18810SHerbert Xu new->pkt_type = old->pkt_type; 517dec18810SHerbert Xu new->ip_summed = old->ip_summed; 518dec18810SHerbert Xu skb_copy_queue_mapping(new, old); 519dec18810SHerbert Xu new->priority = old->priority; 520dec18810SHerbert Xu #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 521dec18810SHerbert Xu new->ipvs_property = old->ipvs_property; 522dec18810SHerbert Xu #endif 523dec18810SHerbert Xu new->protocol = old->protocol; 524dec18810SHerbert Xu new->mark = old->mark; 525dec18810SHerbert Xu __nf_copy(new, old); 526dec18810SHerbert Xu #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ 527dec18810SHerbert Xu defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) 528dec18810SHerbert Xu new->nf_trace = old->nf_trace; 529dec18810SHerbert Xu #endif 530dec18810SHerbert Xu #ifdef CONFIG_NET_SCHED 531dec18810SHerbert Xu new->tc_index = old->tc_index; 532dec18810SHerbert Xu #ifdef CONFIG_NET_CLS_ACT 533dec18810SHerbert Xu new->tc_verd = old->tc_verd; 534dec18810SHerbert Xu #endif 535dec18810SHerbert Xu #endif 5366aa895b0SPatrick McHardy new->vlan_tci = old->vlan_tci; 5376aa895b0SPatrick McHardy 538dec18810SHerbert Xu skb_copy_secmark(new, old); 539dec18810SHerbert Xu } 540dec18810SHerbert Xu 541e0053ec0SHerbert Xu static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) 5421da177e4SLinus Torvalds { 5431da177e4SLinus Torvalds #define C(x) n->x = skb->x 5441da177e4SLinus Torvalds 5451da177e4SLinus Torvalds n->next = n->prev = NULL; 5461da177e4SLinus Torvalds n->sk = NULL; 547dec18810SHerbert Xu __copy_skb_header(n, skb); 548dec18810SHerbert Xu 5491da177e4SLinus Torvalds C(len); 5501da177e4SLinus Torvalds C(data_len); 5513e6b3b2eSAlexey Dobriyan C(mac_len); 552334a8132SPatrick McHardy n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len; 55302f1c89dSPaul Moore n->cloned = 1; 5541da177e4SLinus Torvalds n->nohdr = 0; 5551da177e4SLinus Torvalds n->destructor = NULL; 55602f1c89dSPaul Moore C(iif); 5571da177e4SLinus Torvalds C(tail); 5581da177e4SLinus Torvalds C(end); 55902f1c89dSPaul Moore C(head); 56002f1c89dSPaul Moore C(data); 56102f1c89dSPaul Moore C(truesize); 562d0f09804SJohannes Berg #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE) 563d0f09804SJohannes Berg C(do_not_encrypt); 5648b30b1feSSujith C(requeue); 565d0f09804SJohannes Berg #endif 56602f1c89dSPaul Moore atomic_set(&n->users, 1); 5671da177e4SLinus Torvalds 5681da177e4SLinus Torvalds atomic_inc(&(skb_shinfo(skb)->dataref)); 5691da177e4SLinus Torvalds skb->cloned = 1; 5701da177e4SLinus Torvalds 5711da177e4SLinus Torvalds return n; 572e0053ec0SHerbert Xu #undef C 573e0053ec0SHerbert Xu } 574e0053ec0SHerbert Xu 575e0053ec0SHerbert Xu /** 576e0053ec0SHerbert Xu * skb_morph - morph one skb into another 577e0053ec0SHerbert Xu * @dst: the skb to receive the contents 578e0053ec0SHerbert Xu * @src: the skb to supply the contents 579e0053ec0SHerbert Xu * 580e0053ec0SHerbert Xu * This is identical to skb_clone except that the target skb is 581e0053ec0SHerbert Xu * supplied by the user. 582e0053ec0SHerbert Xu * 583e0053ec0SHerbert Xu * The target skb is returned upon exit. 584e0053ec0SHerbert Xu */ 585e0053ec0SHerbert Xu struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src) 586e0053ec0SHerbert Xu { 5872d4baff8SHerbert Xu skb_release_all(dst); 588e0053ec0SHerbert Xu return __skb_clone(dst, src); 589e0053ec0SHerbert Xu } 590e0053ec0SHerbert Xu EXPORT_SYMBOL_GPL(skb_morph); 591e0053ec0SHerbert Xu 592e0053ec0SHerbert Xu /** 593e0053ec0SHerbert Xu * skb_clone - duplicate an sk_buff 594e0053ec0SHerbert Xu * @skb: buffer to clone 595e0053ec0SHerbert Xu * @gfp_mask: allocation priority 596e0053ec0SHerbert Xu * 597e0053ec0SHerbert Xu * Duplicate an &sk_buff. The new one is not owned by a socket. Both 598e0053ec0SHerbert Xu * copies share the same packet data but not structure. The new 599e0053ec0SHerbert Xu * buffer has a reference count of 1. If the allocation fails the 600e0053ec0SHerbert Xu * function returns %NULL otherwise the new buffer is returned. 601e0053ec0SHerbert Xu * 602e0053ec0SHerbert Xu * If this function is called from an interrupt gfp_mask() must be 603e0053ec0SHerbert Xu * %GFP_ATOMIC. 604e0053ec0SHerbert Xu */ 605e0053ec0SHerbert Xu 606e0053ec0SHerbert Xu struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) 607e0053ec0SHerbert Xu { 608e0053ec0SHerbert Xu struct sk_buff *n; 609e0053ec0SHerbert Xu 610e0053ec0SHerbert Xu n = skb + 1; 611e0053ec0SHerbert Xu if (skb->fclone == SKB_FCLONE_ORIG && 612e0053ec0SHerbert Xu n->fclone == SKB_FCLONE_UNAVAILABLE) { 613e0053ec0SHerbert Xu atomic_t *fclone_ref = (atomic_t *) (n + 1); 614e0053ec0SHerbert Xu n->fclone = SKB_FCLONE_CLONE; 615e0053ec0SHerbert Xu atomic_inc(fclone_ref); 616e0053ec0SHerbert Xu } else { 617e0053ec0SHerbert Xu n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); 618e0053ec0SHerbert Xu if (!n) 619e0053ec0SHerbert Xu return NULL; 620e0053ec0SHerbert Xu n->fclone = SKB_FCLONE_UNAVAILABLE; 621e0053ec0SHerbert Xu } 622e0053ec0SHerbert Xu 623e0053ec0SHerbert Xu return __skb_clone(n, skb); 6241da177e4SLinus Torvalds } 625b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_clone); 6261da177e4SLinus Torvalds 6271da177e4SLinus Torvalds static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 6281da177e4SLinus Torvalds { 6292e07fa9cSArnaldo Carvalho de Melo #ifndef NET_SKBUFF_DATA_USES_OFFSET 6301da177e4SLinus Torvalds /* 6311da177e4SLinus Torvalds * Shift between the two data areas in bytes 6321da177e4SLinus Torvalds */ 6331da177e4SLinus Torvalds unsigned long offset = new->data - old->data; 6342e07fa9cSArnaldo Carvalho de Melo #endif 635dec18810SHerbert Xu 636dec18810SHerbert Xu __copy_skb_header(new, old); 637dec18810SHerbert Xu 6382e07fa9cSArnaldo Carvalho de Melo #ifndef NET_SKBUFF_DATA_USES_OFFSET 6392e07fa9cSArnaldo Carvalho de Melo /* {transport,network,mac}_header are relative to skb->head */ 6402e07fa9cSArnaldo Carvalho de Melo new->transport_header += offset; 6412e07fa9cSArnaldo Carvalho de Melo new->network_header += offset; 6422e07fa9cSArnaldo Carvalho de Melo new->mac_header += offset; 6432e07fa9cSArnaldo Carvalho de Melo #endif 6447967168cSHerbert Xu skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; 6457967168cSHerbert Xu skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; 6467967168cSHerbert Xu skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; 6471da177e4SLinus Torvalds } 6481da177e4SLinus Torvalds 6491da177e4SLinus Torvalds /** 6501da177e4SLinus Torvalds * skb_copy - create private copy of an sk_buff 6511da177e4SLinus Torvalds * @skb: buffer to copy 6521da177e4SLinus Torvalds * @gfp_mask: allocation priority 6531da177e4SLinus Torvalds * 6541da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data. This is used when the 6551da177e4SLinus Torvalds * caller wishes to modify the data and needs a private copy of the 6561da177e4SLinus Torvalds * data to alter. Returns %NULL on failure or the pointer to the buffer 6571da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 6581da177e4SLinus Torvalds * 6591da177e4SLinus Torvalds * As by-product this function converts non-linear &sk_buff to linear 6601da177e4SLinus Torvalds * one, so that &sk_buff becomes completely private and caller is allowed 6611da177e4SLinus Torvalds * to modify all the data of returned buffer. This means that this 6621da177e4SLinus Torvalds * function is not recommended for use in circumstances when only 6631da177e4SLinus Torvalds * header is going to be modified. Use pskb_copy() instead. 6641da177e4SLinus Torvalds */ 6651da177e4SLinus Torvalds 666dd0fc66fSAl Viro struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) 6671da177e4SLinus Torvalds { 6681da177e4SLinus Torvalds int headerlen = skb->data - skb->head; 6691da177e4SLinus Torvalds /* 6701da177e4SLinus Torvalds * Allocate the copy buffer 6711da177e4SLinus Torvalds */ 6724305b541SArnaldo Carvalho de Melo struct sk_buff *n; 6734305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 6744305b541SArnaldo Carvalho de Melo n = alloc_skb(skb->end + skb->data_len, gfp_mask); 6754305b541SArnaldo Carvalho de Melo #else 6764305b541SArnaldo Carvalho de Melo n = alloc_skb(skb->end - skb->head + skb->data_len, gfp_mask); 6774305b541SArnaldo Carvalho de Melo #endif 6781da177e4SLinus Torvalds if (!n) 6791da177e4SLinus Torvalds return NULL; 6801da177e4SLinus Torvalds 6811da177e4SLinus Torvalds /* Set the data pointer */ 6821da177e4SLinus Torvalds skb_reserve(n, headerlen); 6831da177e4SLinus Torvalds /* Set the tail pointer and length */ 6841da177e4SLinus Torvalds skb_put(n, skb->len); 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) 6871da177e4SLinus Torvalds BUG(); 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds copy_skb_header(n, skb); 6901da177e4SLinus Torvalds return n; 6911da177e4SLinus Torvalds } 692b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy); 6931da177e4SLinus Torvalds 6941da177e4SLinus Torvalds /** 6951da177e4SLinus Torvalds * pskb_copy - create copy of an sk_buff with private head. 6961da177e4SLinus Torvalds * @skb: buffer to copy 6971da177e4SLinus Torvalds * @gfp_mask: allocation priority 6981da177e4SLinus Torvalds * 6991da177e4SLinus Torvalds * Make a copy of both an &sk_buff and part of its data, located 7001da177e4SLinus Torvalds * in header. Fragmented data remain shared. This is used when 7011da177e4SLinus Torvalds * the caller wishes to modify only header of &sk_buff and needs 7021da177e4SLinus Torvalds * private copy of the header to alter. Returns %NULL on failure 7031da177e4SLinus Torvalds * or the pointer to the buffer on success. 7041da177e4SLinus Torvalds * The returned buffer has a reference count of 1. 7051da177e4SLinus Torvalds */ 7061da177e4SLinus Torvalds 707dd0fc66fSAl Viro struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask) 7081da177e4SLinus Torvalds { 7091da177e4SLinus Torvalds /* 7101da177e4SLinus Torvalds * Allocate the copy buffer 7111da177e4SLinus Torvalds */ 7124305b541SArnaldo Carvalho de Melo struct sk_buff *n; 7134305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 7144305b541SArnaldo Carvalho de Melo n = alloc_skb(skb->end, gfp_mask); 7154305b541SArnaldo Carvalho de Melo #else 7164305b541SArnaldo Carvalho de Melo n = alloc_skb(skb->end - skb->head, gfp_mask); 7174305b541SArnaldo Carvalho de Melo #endif 7181da177e4SLinus Torvalds if (!n) 7191da177e4SLinus Torvalds goto out; 7201da177e4SLinus Torvalds 7211da177e4SLinus Torvalds /* Set the data pointer */ 7221da177e4SLinus Torvalds skb_reserve(n, skb->data - skb->head); 7231da177e4SLinus Torvalds /* Set the tail pointer and length */ 7241da177e4SLinus Torvalds skb_put(n, skb_headlen(skb)); 7251da177e4SLinus Torvalds /* Copy the bytes */ 726d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data(skb, n->data, n->len); 7271da177e4SLinus Torvalds 72825f484a6SHerbert Xu n->truesize += skb->data_len; 7291da177e4SLinus Torvalds n->data_len = skb->data_len; 7301da177e4SLinus Torvalds n->len = skb->len; 7311da177e4SLinus Torvalds 7321da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 7331da177e4SLinus Torvalds int i; 7341da177e4SLinus Torvalds 7351da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 7361da177e4SLinus Torvalds skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; 7371da177e4SLinus Torvalds get_page(skb_shinfo(n)->frags[i].page); 7381da177e4SLinus Torvalds } 7391da177e4SLinus Torvalds skb_shinfo(n)->nr_frags = i; 7401da177e4SLinus Torvalds } 7411da177e4SLinus Torvalds 7421da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 7431da177e4SLinus Torvalds skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; 7441da177e4SLinus Torvalds skb_clone_fraglist(n); 7451da177e4SLinus Torvalds } 7461da177e4SLinus Torvalds 7471da177e4SLinus Torvalds copy_skb_header(n, skb); 7481da177e4SLinus Torvalds out: 7491da177e4SLinus Torvalds return n; 7501da177e4SLinus Torvalds } 751b4ac530fSDavid S. Miller EXPORT_SYMBOL(pskb_copy); 7521da177e4SLinus Torvalds 7531da177e4SLinus Torvalds /** 7541da177e4SLinus Torvalds * pskb_expand_head - reallocate header of &sk_buff 7551da177e4SLinus Torvalds * @skb: buffer to reallocate 7561da177e4SLinus Torvalds * @nhead: room to add at head 7571da177e4SLinus Torvalds * @ntail: room to add at tail 7581da177e4SLinus Torvalds * @gfp_mask: allocation priority 7591da177e4SLinus Torvalds * 7601da177e4SLinus Torvalds * Expands (or creates identical copy, if &nhead and &ntail are zero) 7611da177e4SLinus Torvalds * header of skb. &sk_buff itself is not changed. &sk_buff MUST have 7621da177e4SLinus Torvalds * reference count of 1. Returns zero in the case of success or error, 7631da177e4SLinus Torvalds * if expansion failed. In the last case, &sk_buff is not changed. 7641da177e4SLinus Torvalds * 7651da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 7661da177e4SLinus Torvalds * reloaded after call to this function. 7671da177e4SLinus Torvalds */ 7681da177e4SLinus Torvalds 76986a76cafSVictor Fusco int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, 770dd0fc66fSAl Viro gfp_t gfp_mask) 7711da177e4SLinus Torvalds { 7721da177e4SLinus Torvalds int i; 7731da177e4SLinus Torvalds u8 *data; 7744305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 7754305b541SArnaldo Carvalho de Melo int size = nhead + skb->end + ntail; 7764305b541SArnaldo Carvalho de Melo #else 7771da177e4SLinus Torvalds int size = nhead + (skb->end - skb->head) + ntail; 7784305b541SArnaldo Carvalho de Melo #endif 7791da177e4SLinus Torvalds long off; 7801da177e4SLinus Torvalds 7814edd87adSHerbert Xu BUG_ON(nhead < 0); 7824edd87adSHerbert Xu 7831da177e4SLinus Torvalds if (skb_shared(skb)) 7841da177e4SLinus Torvalds BUG(); 7851da177e4SLinus Torvalds 7861da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 7871da177e4SLinus Torvalds 7881da177e4SLinus Torvalds data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); 7891da177e4SLinus Torvalds if (!data) 7901da177e4SLinus Torvalds goto nodata; 7911da177e4SLinus Torvalds 7921da177e4SLinus Torvalds /* Copy only real data... and, alas, header. This should be 7931da177e4SLinus Torvalds * optimized for the cases when header is void. */ 7944305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 795b6ccc67dSMikael Pettersson memcpy(data + nhead, skb->head, skb->tail); 7964305b541SArnaldo Carvalho de Melo #else 797b6ccc67dSMikael Pettersson memcpy(data + nhead, skb->head, skb->tail - skb->head); 79827a884dcSArnaldo Carvalho de Melo #endif 7994305b541SArnaldo Carvalho de Melo memcpy(data + size, skb_end_pointer(skb), 8004305b541SArnaldo Carvalho de Melo sizeof(struct skb_shared_info)); 8011da177e4SLinus Torvalds 8021da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 8031da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 8041da177e4SLinus Torvalds 8051da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 8061da177e4SLinus Torvalds skb_clone_fraglist(skb); 8071da177e4SLinus Torvalds 8081da177e4SLinus Torvalds skb_release_data(skb); 8091da177e4SLinus Torvalds 8101da177e4SLinus Torvalds off = (data + nhead) - skb->head; 8111da177e4SLinus Torvalds 8121da177e4SLinus Torvalds skb->head = data; 8131da177e4SLinus Torvalds skb->data += off; 8144305b541SArnaldo Carvalho de Melo #ifdef NET_SKBUFF_DATA_USES_OFFSET 8154305b541SArnaldo Carvalho de Melo skb->end = size; 81656eb8882SPatrick McHardy off = nhead; 8174305b541SArnaldo Carvalho de Melo #else 8184305b541SArnaldo Carvalho de Melo skb->end = skb->head + size; 81956eb8882SPatrick McHardy #endif 82027a884dcSArnaldo Carvalho de Melo /* {transport,network,mac}_header and tail are relative to skb->head */ 82127a884dcSArnaldo Carvalho de Melo skb->tail += off; 822b0e380b1SArnaldo Carvalho de Melo skb->transport_header += off; 823b0e380b1SArnaldo Carvalho de Melo skb->network_header += off; 824b0e380b1SArnaldo Carvalho de Melo skb->mac_header += off; 825172a863fSHerbert Xu skb->csum_start += nhead; 8261da177e4SLinus Torvalds skb->cloned = 0; 827334a8132SPatrick McHardy skb->hdr_len = 0; 8281da177e4SLinus Torvalds skb->nohdr = 0; 8291da177e4SLinus Torvalds atomic_set(&skb_shinfo(skb)->dataref, 1); 8301da177e4SLinus Torvalds return 0; 8311da177e4SLinus Torvalds 8321da177e4SLinus Torvalds nodata: 8331da177e4SLinus Torvalds return -ENOMEM; 8341da177e4SLinus Torvalds } 835b4ac530fSDavid S. Miller EXPORT_SYMBOL(pskb_expand_head); 8361da177e4SLinus Torvalds 8371da177e4SLinus Torvalds /* Make private copy of skb with writable head and some headroom */ 8381da177e4SLinus Torvalds 8391da177e4SLinus Torvalds struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) 8401da177e4SLinus Torvalds { 8411da177e4SLinus Torvalds struct sk_buff *skb2; 8421da177e4SLinus Torvalds int delta = headroom - skb_headroom(skb); 8431da177e4SLinus Torvalds 8441da177e4SLinus Torvalds if (delta <= 0) 8451da177e4SLinus Torvalds skb2 = pskb_copy(skb, GFP_ATOMIC); 8461da177e4SLinus Torvalds else { 8471da177e4SLinus Torvalds skb2 = skb_clone(skb, GFP_ATOMIC); 8481da177e4SLinus Torvalds if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, 8491da177e4SLinus Torvalds GFP_ATOMIC)) { 8501da177e4SLinus Torvalds kfree_skb(skb2); 8511da177e4SLinus Torvalds skb2 = NULL; 8521da177e4SLinus Torvalds } 8531da177e4SLinus Torvalds } 8541da177e4SLinus Torvalds return skb2; 8551da177e4SLinus Torvalds } 856b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_realloc_headroom); 8571da177e4SLinus Torvalds 8581da177e4SLinus Torvalds /** 8591da177e4SLinus Torvalds * skb_copy_expand - copy and expand sk_buff 8601da177e4SLinus Torvalds * @skb: buffer to copy 8611da177e4SLinus Torvalds * @newheadroom: new free bytes at head 8621da177e4SLinus Torvalds * @newtailroom: new free bytes at tail 8631da177e4SLinus Torvalds * @gfp_mask: allocation priority 8641da177e4SLinus Torvalds * 8651da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data and while doing so 8661da177e4SLinus Torvalds * allocate additional space. 8671da177e4SLinus Torvalds * 8681da177e4SLinus Torvalds * This is used when the caller wishes to modify the data and needs a 8691da177e4SLinus Torvalds * private copy of the data to alter as well as more space for new fields. 8701da177e4SLinus Torvalds * Returns %NULL on failure or the pointer to the buffer 8711da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 8721da177e4SLinus Torvalds * 8731da177e4SLinus Torvalds * You must pass %GFP_ATOMIC as the allocation priority if this function 8741da177e4SLinus Torvalds * is called from an interrupt. 8751da177e4SLinus Torvalds */ 8761da177e4SLinus Torvalds struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 87786a76cafSVictor Fusco int newheadroom, int newtailroom, 878dd0fc66fSAl Viro gfp_t gfp_mask) 8791da177e4SLinus Torvalds { 8801da177e4SLinus Torvalds /* 8811da177e4SLinus Torvalds * Allocate the copy buffer 8821da177e4SLinus Torvalds */ 8831da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, 8841da177e4SLinus Torvalds gfp_mask); 885efd1e8d5SPatrick McHardy int oldheadroom = skb_headroom(skb); 8861da177e4SLinus Torvalds int head_copy_len, head_copy_off; 88752886051SHerbert Xu int off; 8881da177e4SLinus Torvalds 8891da177e4SLinus Torvalds if (!n) 8901da177e4SLinus Torvalds return NULL; 8911da177e4SLinus Torvalds 8921da177e4SLinus Torvalds skb_reserve(n, newheadroom); 8931da177e4SLinus Torvalds 8941da177e4SLinus Torvalds /* Set the tail pointer and length */ 8951da177e4SLinus Torvalds skb_put(n, skb->len); 8961da177e4SLinus Torvalds 897efd1e8d5SPatrick McHardy head_copy_len = oldheadroom; 8981da177e4SLinus Torvalds head_copy_off = 0; 8991da177e4SLinus Torvalds if (newheadroom <= head_copy_len) 9001da177e4SLinus Torvalds head_copy_len = newheadroom; 9011da177e4SLinus Torvalds else 9021da177e4SLinus Torvalds head_copy_off = newheadroom - head_copy_len; 9031da177e4SLinus Torvalds 9041da177e4SLinus Torvalds /* Copy the linear header and data. */ 9051da177e4SLinus Torvalds if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, 9061da177e4SLinus Torvalds skb->len + head_copy_len)) 9071da177e4SLinus Torvalds BUG(); 9081da177e4SLinus Torvalds 9091da177e4SLinus Torvalds copy_skb_header(n, skb); 9101da177e4SLinus Torvalds 911efd1e8d5SPatrick McHardy off = newheadroom - oldheadroom; 91252886051SHerbert Xu n->csum_start += off; 91352886051SHerbert Xu #ifdef NET_SKBUFF_DATA_USES_OFFSET 914efd1e8d5SPatrick McHardy n->transport_header += off; 915efd1e8d5SPatrick McHardy n->network_header += off; 916efd1e8d5SPatrick McHardy n->mac_header += off; 91752886051SHerbert Xu #endif 918efd1e8d5SPatrick McHardy 9191da177e4SLinus Torvalds return n; 9201da177e4SLinus Torvalds } 921b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_expand); 9221da177e4SLinus Torvalds 9231da177e4SLinus Torvalds /** 9241da177e4SLinus Torvalds * skb_pad - zero pad the tail of an skb 9251da177e4SLinus Torvalds * @skb: buffer to pad 9261da177e4SLinus Torvalds * @pad: space to pad 9271da177e4SLinus Torvalds * 9281da177e4SLinus Torvalds * Ensure that a buffer is followed by a padding area that is zero 9291da177e4SLinus Torvalds * filled. Used by network drivers which may DMA or transfer data 9301da177e4SLinus Torvalds * beyond the buffer end onto the wire. 9311da177e4SLinus Torvalds * 9325b057c6bSHerbert Xu * May return error in out of memory cases. The skb is freed on error. 9331da177e4SLinus Torvalds */ 9341da177e4SLinus Torvalds 9355b057c6bSHerbert Xu int skb_pad(struct sk_buff *skb, int pad) 9361da177e4SLinus Torvalds { 9375b057c6bSHerbert Xu int err; 9385b057c6bSHerbert Xu int ntail; 9391da177e4SLinus Torvalds 9401da177e4SLinus Torvalds /* If the skbuff is non linear tailroom is always zero.. */ 9415b057c6bSHerbert Xu if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { 9421da177e4SLinus Torvalds memset(skb->data+skb->len, 0, pad); 9435b057c6bSHerbert Xu return 0; 9441da177e4SLinus Torvalds } 9451da177e4SLinus Torvalds 9464305b541SArnaldo Carvalho de Melo ntail = skb->data_len + pad - (skb->end - skb->tail); 9475b057c6bSHerbert Xu if (likely(skb_cloned(skb) || ntail > 0)) { 9485b057c6bSHerbert Xu err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); 9495b057c6bSHerbert Xu if (unlikely(err)) 9505b057c6bSHerbert Xu goto free_skb; 9515b057c6bSHerbert Xu } 9525b057c6bSHerbert Xu 9535b057c6bSHerbert Xu /* FIXME: The use of this function with non-linear skb's really needs 9545b057c6bSHerbert Xu * to be audited. 9555b057c6bSHerbert Xu */ 9565b057c6bSHerbert Xu err = skb_linearize(skb); 9575b057c6bSHerbert Xu if (unlikely(err)) 9585b057c6bSHerbert Xu goto free_skb; 9595b057c6bSHerbert Xu 9605b057c6bSHerbert Xu memset(skb->data + skb->len, 0, pad); 9615b057c6bSHerbert Xu return 0; 9625b057c6bSHerbert Xu 9635b057c6bSHerbert Xu free_skb: 9641da177e4SLinus Torvalds kfree_skb(skb); 9655b057c6bSHerbert Xu return err; 9661da177e4SLinus Torvalds } 967b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_pad); 9681da177e4SLinus Torvalds 9690dde3e16SIlpo Järvinen /** 9700dde3e16SIlpo Järvinen * skb_put - add data to a buffer 9710dde3e16SIlpo Järvinen * @skb: buffer to use 9720dde3e16SIlpo Järvinen * @len: amount of data to add 9730dde3e16SIlpo Järvinen * 9740dde3e16SIlpo Järvinen * This function extends the used data area of the buffer. If this would 9750dde3e16SIlpo Järvinen * exceed the total buffer size the kernel will panic. A pointer to the 9760dde3e16SIlpo Järvinen * first byte of the extra data is returned. 9770dde3e16SIlpo Järvinen */ 9780dde3e16SIlpo Järvinen unsigned char *skb_put(struct sk_buff *skb, unsigned int len) 9790dde3e16SIlpo Järvinen { 9800dde3e16SIlpo Järvinen unsigned char *tmp = skb_tail_pointer(skb); 9810dde3e16SIlpo Järvinen SKB_LINEAR_ASSERT(skb); 9820dde3e16SIlpo Järvinen skb->tail += len; 9830dde3e16SIlpo Järvinen skb->len += len; 9840dde3e16SIlpo Järvinen if (unlikely(skb->tail > skb->end)) 9850dde3e16SIlpo Järvinen skb_over_panic(skb, len, __builtin_return_address(0)); 9860dde3e16SIlpo Järvinen return tmp; 9870dde3e16SIlpo Järvinen } 9880dde3e16SIlpo Järvinen EXPORT_SYMBOL(skb_put); 9890dde3e16SIlpo Järvinen 9906be8ac2fSIlpo Järvinen /** 991c2aa270aSIlpo Järvinen * skb_push - add data to the start of a buffer 992c2aa270aSIlpo Järvinen * @skb: buffer to use 993c2aa270aSIlpo Järvinen * @len: amount of data to add 994c2aa270aSIlpo Järvinen * 995c2aa270aSIlpo Järvinen * This function extends the used data area of the buffer at the buffer 996c2aa270aSIlpo Järvinen * start. If this would exceed the total buffer headroom the kernel will 997c2aa270aSIlpo Järvinen * panic. A pointer to the first byte of the extra data is returned. 998c2aa270aSIlpo Järvinen */ 999c2aa270aSIlpo Järvinen unsigned char *skb_push(struct sk_buff *skb, unsigned int len) 1000c2aa270aSIlpo Järvinen { 1001c2aa270aSIlpo Järvinen skb->data -= len; 1002c2aa270aSIlpo Järvinen skb->len += len; 1003c2aa270aSIlpo Järvinen if (unlikely(skb->data<skb->head)) 1004c2aa270aSIlpo Järvinen skb_under_panic(skb, len, __builtin_return_address(0)); 1005c2aa270aSIlpo Järvinen return skb->data; 1006c2aa270aSIlpo Järvinen } 1007c2aa270aSIlpo Järvinen EXPORT_SYMBOL(skb_push); 1008c2aa270aSIlpo Järvinen 1009c2aa270aSIlpo Järvinen /** 10106be8ac2fSIlpo Järvinen * skb_pull - remove data from the start of a buffer 10116be8ac2fSIlpo Järvinen * @skb: buffer to use 10126be8ac2fSIlpo Järvinen * @len: amount of data to remove 10136be8ac2fSIlpo Järvinen * 10146be8ac2fSIlpo Järvinen * This function removes data from the start of a buffer, returning 10156be8ac2fSIlpo Järvinen * the memory to the headroom. A pointer to the next data in the buffer 10166be8ac2fSIlpo Järvinen * is returned. Once the data has been pulled future pushes will overwrite 10176be8ac2fSIlpo Järvinen * the old data. 10186be8ac2fSIlpo Järvinen */ 10196be8ac2fSIlpo Järvinen unsigned char *skb_pull(struct sk_buff *skb, unsigned int len) 10206be8ac2fSIlpo Järvinen { 10216be8ac2fSIlpo Järvinen return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len); 10226be8ac2fSIlpo Järvinen } 10236be8ac2fSIlpo Järvinen EXPORT_SYMBOL(skb_pull); 10246be8ac2fSIlpo Järvinen 1025419ae74eSIlpo Järvinen /** 1026419ae74eSIlpo Järvinen * skb_trim - remove end from a buffer 1027419ae74eSIlpo Järvinen * @skb: buffer to alter 1028419ae74eSIlpo Järvinen * @len: new length 1029419ae74eSIlpo Järvinen * 1030419ae74eSIlpo Järvinen * Cut the length of a buffer down by removing data from the tail. If 1031419ae74eSIlpo Järvinen * the buffer is already under the length specified it is not modified. 1032419ae74eSIlpo Järvinen * The skb must be linear. 1033419ae74eSIlpo Järvinen */ 1034419ae74eSIlpo Järvinen void skb_trim(struct sk_buff *skb, unsigned int len) 1035419ae74eSIlpo Järvinen { 1036419ae74eSIlpo Järvinen if (skb->len > len) 1037419ae74eSIlpo Järvinen __skb_trim(skb, len); 1038419ae74eSIlpo Järvinen } 1039419ae74eSIlpo Järvinen EXPORT_SYMBOL(skb_trim); 1040419ae74eSIlpo Järvinen 10413cc0e873SHerbert Xu /* Trims skb to length len. It can change skb pointers. 10421da177e4SLinus Torvalds */ 10431da177e4SLinus Torvalds 10443cc0e873SHerbert Xu int ___pskb_trim(struct sk_buff *skb, unsigned int len) 10451da177e4SLinus Torvalds { 104627b437c8SHerbert Xu struct sk_buff **fragp; 104727b437c8SHerbert Xu struct sk_buff *frag; 10481da177e4SLinus Torvalds int offset = skb_headlen(skb); 10491da177e4SLinus Torvalds int nfrags = skb_shinfo(skb)->nr_frags; 10501da177e4SLinus Torvalds int i; 105127b437c8SHerbert Xu int err; 105227b437c8SHerbert Xu 105327b437c8SHerbert Xu if (skb_cloned(skb) && 105427b437c8SHerbert Xu unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) 105527b437c8SHerbert Xu return err; 10561da177e4SLinus Torvalds 1057f4d26fb3SHerbert Xu i = 0; 1058f4d26fb3SHerbert Xu if (offset >= len) 1059f4d26fb3SHerbert Xu goto drop_pages; 1060f4d26fb3SHerbert Xu 1061f4d26fb3SHerbert Xu for (; i < nfrags; i++) { 10621da177e4SLinus Torvalds int end = offset + skb_shinfo(skb)->frags[i].size; 106327b437c8SHerbert Xu 106427b437c8SHerbert Xu if (end < len) { 10651da177e4SLinus Torvalds offset = end; 106627b437c8SHerbert Xu continue; 10671da177e4SLinus Torvalds } 10681da177e4SLinus Torvalds 106927b437c8SHerbert Xu skb_shinfo(skb)->frags[i++].size = len - offset; 107027b437c8SHerbert Xu 1071f4d26fb3SHerbert Xu drop_pages: 107227b437c8SHerbert Xu skb_shinfo(skb)->nr_frags = i; 107327b437c8SHerbert Xu 107427b437c8SHerbert Xu for (; i < nfrags; i++) 107527b437c8SHerbert Xu put_page(skb_shinfo(skb)->frags[i].page); 107627b437c8SHerbert Xu 107727b437c8SHerbert Xu if (skb_shinfo(skb)->frag_list) 107827b437c8SHerbert Xu skb_drop_fraglist(skb); 1079f4d26fb3SHerbert Xu goto done; 108027b437c8SHerbert Xu } 108127b437c8SHerbert Xu 108227b437c8SHerbert Xu for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); 108327b437c8SHerbert Xu fragp = &frag->next) { 108427b437c8SHerbert Xu int end = offset + frag->len; 108527b437c8SHerbert Xu 108627b437c8SHerbert Xu if (skb_shared(frag)) { 108727b437c8SHerbert Xu struct sk_buff *nfrag; 108827b437c8SHerbert Xu 108927b437c8SHerbert Xu nfrag = skb_clone(frag, GFP_ATOMIC); 109027b437c8SHerbert Xu if (unlikely(!nfrag)) 109127b437c8SHerbert Xu return -ENOMEM; 109227b437c8SHerbert Xu 109327b437c8SHerbert Xu nfrag->next = frag->next; 1094f4d26fb3SHerbert Xu kfree_skb(frag); 109527b437c8SHerbert Xu frag = nfrag; 109627b437c8SHerbert Xu *fragp = frag; 109727b437c8SHerbert Xu } 109827b437c8SHerbert Xu 109927b437c8SHerbert Xu if (end < len) { 110027b437c8SHerbert Xu offset = end; 110127b437c8SHerbert Xu continue; 110227b437c8SHerbert Xu } 110327b437c8SHerbert Xu 110427b437c8SHerbert Xu if (end > len && 110527b437c8SHerbert Xu unlikely((err = pskb_trim(frag, len - offset)))) 110627b437c8SHerbert Xu return err; 110727b437c8SHerbert Xu 110827b437c8SHerbert Xu if (frag->next) 110927b437c8SHerbert Xu skb_drop_list(&frag->next); 111027b437c8SHerbert Xu break; 111127b437c8SHerbert Xu } 111227b437c8SHerbert Xu 1113f4d26fb3SHerbert Xu done: 111427b437c8SHerbert Xu if (len > skb_headlen(skb)) { 11151da177e4SLinus Torvalds skb->data_len -= skb->len - len; 11161da177e4SLinus Torvalds skb->len = len; 11171da177e4SLinus Torvalds } else { 11181da177e4SLinus Torvalds skb->len = len; 11191da177e4SLinus Torvalds skb->data_len = 0; 112027a884dcSArnaldo Carvalho de Melo skb_set_tail_pointer(skb, len); 11211da177e4SLinus Torvalds } 11221da177e4SLinus Torvalds 11231da177e4SLinus Torvalds return 0; 11241da177e4SLinus Torvalds } 1125b4ac530fSDavid S. Miller EXPORT_SYMBOL(___pskb_trim); 11261da177e4SLinus Torvalds 11271da177e4SLinus Torvalds /** 11281da177e4SLinus Torvalds * __pskb_pull_tail - advance tail of skb header 11291da177e4SLinus Torvalds * @skb: buffer to reallocate 11301da177e4SLinus Torvalds * @delta: number of bytes to advance tail 11311da177e4SLinus Torvalds * 11321da177e4SLinus Torvalds * The function makes a sense only on a fragmented &sk_buff, 11331da177e4SLinus Torvalds * it expands header moving its tail forward and copying necessary 11341da177e4SLinus Torvalds * data from fragmented part. 11351da177e4SLinus Torvalds * 11361da177e4SLinus Torvalds * &sk_buff MUST have reference count of 1. 11371da177e4SLinus Torvalds * 11381da177e4SLinus Torvalds * Returns %NULL (and &sk_buff does not change) if pull failed 11391da177e4SLinus Torvalds * or value of new tail of skb in the case of success. 11401da177e4SLinus Torvalds * 11411da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 11421da177e4SLinus Torvalds * reloaded after call to this function. 11431da177e4SLinus Torvalds */ 11441da177e4SLinus Torvalds 11451da177e4SLinus Torvalds /* Moves tail of skb head forward, copying data from fragmented part, 11461da177e4SLinus Torvalds * when it is necessary. 11471da177e4SLinus Torvalds * 1. It may fail due to malloc failure. 11481da177e4SLinus Torvalds * 2. It may change skb pointers. 11491da177e4SLinus Torvalds * 11501da177e4SLinus Torvalds * It is pretty complicated. Luckily, it is called only in exceptional cases. 11511da177e4SLinus Torvalds */ 11521da177e4SLinus Torvalds unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) 11531da177e4SLinus Torvalds { 11541da177e4SLinus Torvalds /* If skb has not enough free space at tail, get new one 11551da177e4SLinus Torvalds * plus 128 bytes for future expansions. If we have enough 11561da177e4SLinus Torvalds * room at tail, reallocate without expansion only if skb is cloned. 11571da177e4SLinus Torvalds */ 11584305b541SArnaldo Carvalho de Melo int i, k, eat = (skb->tail + delta) - skb->end; 11591da177e4SLinus Torvalds 11601da177e4SLinus Torvalds if (eat > 0 || skb_cloned(skb)) { 11611da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, 11621da177e4SLinus Torvalds GFP_ATOMIC)) 11631da177e4SLinus Torvalds return NULL; 11641da177e4SLinus Torvalds } 11651da177e4SLinus Torvalds 116627a884dcSArnaldo Carvalho de Melo if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta)) 11671da177e4SLinus Torvalds BUG(); 11681da177e4SLinus Torvalds 11691da177e4SLinus Torvalds /* Optimization: no fragments, no reasons to preestimate 11701da177e4SLinus Torvalds * size of pulled pages. Superb. 11711da177e4SLinus Torvalds */ 11721da177e4SLinus Torvalds if (!skb_shinfo(skb)->frag_list) 11731da177e4SLinus Torvalds goto pull_pages; 11741da177e4SLinus Torvalds 11751da177e4SLinus Torvalds /* Estimate size of pulled pages. */ 11761da177e4SLinus Torvalds eat = delta; 11771da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 11781da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size >= eat) 11791da177e4SLinus Torvalds goto pull_pages; 11801da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 11811da177e4SLinus Torvalds } 11821da177e4SLinus Torvalds 11831da177e4SLinus Torvalds /* If we need update frag list, we are in troubles. 11841da177e4SLinus Torvalds * Certainly, it possible to add an offset to skb data, 11851da177e4SLinus Torvalds * but taking into account that pulling is expected to 11861da177e4SLinus Torvalds * be very rare operation, it is worth to fight against 11871da177e4SLinus Torvalds * further bloating skb head and crucify ourselves here instead. 11881da177e4SLinus Torvalds * Pure masohism, indeed. 8)8) 11891da177e4SLinus Torvalds */ 11901da177e4SLinus Torvalds if (eat) { 11911da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 11921da177e4SLinus Torvalds struct sk_buff *clone = NULL; 11931da177e4SLinus Torvalds struct sk_buff *insp = NULL; 11941da177e4SLinus Torvalds 11951da177e4SLinus Torvalds do { 119609a62660SKris Katterjohn BUG_ON(!list); 11971da177e4SLinus Torvalds 11981da177e4SLinus Torvalds if (list->len <= eat) { 11991da177e4SLinus Torvalds /* Eaten as whole. */ 12001da177e4SLinus Torvalds eat -= list->len; 12011da177e4SLinus Torvalds list = list->next; 12021da177e4SLinus Torvalds insp = list; 12031da177e4SLinus Torvalds } else { 12041da177e4SLinus Torvalds /* Eaten partially. */ 12051da177e4SLinus Torvalds 12061da177e4SLinus Torvalds if (skb_shared(list)) { 12071da177e4SLinus Torvalds /* Sucks! We need to fork list. :-( */ 12081da177e4SLinus Torvalds clone = skb_clone(list, GFP_ATOMIC); 12091da177e4SLinus Torvalds if (!clone) 12101da177e4SLinus Torvalds return NULL; 12111da177e4SLinus Torvalds insp = list->next; 12121da177e4SLinus Torvalds list = clone; 12131da177e4SLinus Torvalds } else { 12141da177e4SLinus Torvalds /* This may be pulled without 12151da177e4SLinus Torvalds * problems. */ 12161da177e4SLinus Torvalds insp = list; 12171da177e4SLinus Torvalds } 12181da177e4SLinus Torvalds if (!pskb_pull(list, eat)) { 12191da177e4SLinus Torvalds if (clone) 12201da177e4SLinus Torvalds kfree_skb(clone); 12211da177e4SLinus Torvalds return NULL; 12221da177e4SLinus Torvalds } 12231da177e4SLinus Torvalds break; 12241da177e4SLinus Torvalds } 12251da177e4SLinus Torvalds } while (eat); 12261da177e4SLinus Torvalds 12271da177e4SLinus Torvalds /* Free pulled out fragments. */ 12281da177e4SLinus Torvalds while ((list = skb_shinfo(skb)->frag_list) != insp) { 12291da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = list->next; 12301da177e4SLinus Torvalds kfree_skb(list); 12311da177e4SLinus Torvalds } 12321da177e4SLinus Torvalds /* And insert new clone at head. */ 12331da177e4SLinus Torvalds if (clone) { 12341da177e4SLinus Torvalds clone->next = list; 12351da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = clone; 12361da177e4SLinus Torvalds } 12371da177e4SLinus Torvalds } 12381da177e4SLinus Torvalds /* Success! Now we may commit changes to skb data. */ 12391da177e4SLinus Torvalds 12401da177e4SLinus Torvalds pull_pages: 12411da177e4SLinus Torvalds eat = delta; 12421da177e4SLinus Torvalds k = 0; 12431da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 12441da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size <= eat) { 12451da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 12461da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 12471da177e4SLinus Torvalds } else { 12481da177e4SLinus Torvalds skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; 12491da177e4SLinus Torvalds if (eat) { 12501da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].page_offset += eat; 12511da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].size -= eat; 12521da177e4SLinus Torvalds eat = 0; 12531da177e4SLinus Torvalds } 12541da177e4SLinus Torvalds k++; 12551da177e4SLinus Torvalds } 12561da177e4SLinus Torvalds } 12571da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = k; 12581da177e4SLinus Torvalds 12591da177e4SLinus Torvalds skb->tail += delta; 12601da177e4SLinus Torvalds skb->data_len -= delta; 12611da177e4SLinus Torvalds 126227a884dcSArnaldo Carvalho de Melo return skb_tail_pointer(skb); 12631da177e4SLinus Torvalds } 1264b4ac530fSDavid S. Miller EXPORT_SYMBOL(__pskb_pull_tail); 12651da177e4SLinus Torvalds 12661da177e4SLinus Torvalds /* Copy some data bits from skb to kernel buffer. */ 12671da177e4SLinus Torvalds 12681da177e4SLinus Torvalds int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) 12691da177e4SLinus Torvalds { 12701da177e4SLinus Torvalds int i, copy; 12711a028e50SDavid S. Miller int start = skb_headlen(skb); 12721da177e4SLinus Torvalds 12731da177e4SLinus Torvalds if (offset > (int)skb->len - len) 12741da177e4SLinus Torvalds goto fault; 12751da177e4SLinus Torvalds 12761da177e4SLinus Torvalds /* Copy header. */ 12771a028e50SDavid S. Miller if ((copy = start - offset) > 0) { 12781da177e4SLinus Torvalds if (copy > len) 12791da177e4SLinus Torvalds copy = len; 1280d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, offset, to, copy); 12811da177e4SLinus Torvalds if ((len -= copy) == 0) 12821da177e4SLinus Torvalds return 0; 12831da177e4SLinus Torvalds offset += copy; 12841da177e4SLinus Torvalds to += copy; 12851da177e4SLinus Torvalds } 12861da177e4SLinus Torvalds 12871da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 12881a028e50SDavid S. Miller int end; 12891da177e4SLinus Torvalds 1290547b792cSIlpo Järvinen WARN_ON(start > offset + len); 12911a028e50SDavid S. Miller 12921a028e50SDavid S. Miller end = start + skb_shinfo(skb)->frags[i].size; 12931da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12941da177e4SLinus Torvalds u8 *vaddr; 12951da177e4SLinus Torvalds 12961da177e4SLinus Torvalds if (copy > len) 12971da177e4SLinus Torvalds copy = len; 12981da177e4SLinus Torvalds 12991da177e4SLinus Torvalds vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); 13001da177e4SLinus Torvalds memcpy(to, 13011a028e50SDavid S. Miller vaddr + skb_shinfo(skb)->frags[i].page_offset+ 13021a028e50SDavid S. Miller offset - start, copy); 13031da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 13041da177e4SLinus Torvalds 13051da177e4SLinus Torvalds if ((len -= copy) == 0) 13061da177e4SLinus Torvalds return 0; 13071da177e4SLinus Torvalds offset += copy; 13081da177e4SLinus Torvalds to += copy; 13091da177e4SLinus Torvalds } 13101a028e50SDavid S. Miller start = end; 13111da177e4SLinus Torvalds } 13121da177e4SLinus Torvalds 13131da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 13141da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 13151da177e4SLinus Torvalds 13161da177e4SLinus Torvalds for (; list; list = list->next) { 13171a028e50SDavid S. Miller int end; 13181da177e4SLinus Torvalds 1319547b792cSIlpo Järvinen WARN_ON(start > offset + len); 13201a028e50SDavid S. Miller 13211a028e50SDavid S. Miller end = start + list->len; 13221da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 13231da177e4SLinus Torvalds if (copy > len) 13241da177e4SLinus Torvalds copy = len; 13251a028e50SDavid S. Miller if (skb_copy_bits(list, offset - start, 13261a028e50SDavid S. Miller to, copy)) 13271da177e4SLinus Torvalds goto fault; 13281da177e4SLinus Torvalds if ((len -= copy) == 0) 13291da177e4SLinus Torvalds return 0; 13301da177e4SLinus Torvalds offset += copy; 13311da177e4SLinus Torvalds to += copy; 13321da177e4SLinus Torvalds } 13331a028e50SDavid S. Miller start = end; 13341da177e4SLinus Torvalds } 13351da177e4SLinus Torvalds } 13361da177e4SLinus Torvalds if (!len) 13371da177e4SLinus Torvalds return 0; 13381da177e4SLinus Torvalds 13391da177e4SLinus Torvalds fault: 13401da177e4SLinus Torvalds return -EFAULT; 13411da177e4SLinus Torvalds } 1342b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_bits); 13431da177e4SLinus Torvalds 13449c55e01cSJens Axboe /* 13459c55e01cSJens Axboe * Callback from splice_to_pipe(), if we need to release some pages 13469c55e01cSJens Axboe * at the end of the spd in case we error'ed out in filling the pipe. 13479c55e01cSJens Axboe */ 13489c55e01cSJens Axboe static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) 13499c55e01cSJens Axboe { 13508b9d3728SJarek Poplawski put_page(spd->pages[i]); 13518b9d3728SJarek Poplawski } 13529c55e01cSJens Axboe 13534fb66994SJarek Poplawski static inline struct page *linear_to_page(struct page *page, unsigned int *len, 13544fb66994SJarek Poplawski unsigned int *offset, 13554fb66994SJarek Poplawski struct sk_buff *skb) 13568b9d3728SJarek Poplawski { 13574fb66994SJarek Poplawski struct sock *sk = skb->sk; 13584fb66994SJarek Poplawski struct page *p = sk->sk_sndmsg_page; 13594fb66994SJarek Poplawski unsigned int off; 13608b9d3728SJarek Poplawski 13614fb66994SJarek Poplawski if (!p) { 13624fb66994SJarek Poplawski new_page: 13634fb66994SJarek Poplawski p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0); 13648b9d3728SJarek Poplawski if (!p) 13658b9d3728SJarek Poplawski return NULL; 13664fb66994SJarek Poplawski 13674fb66994SJarek Poplawski off = sk->sk_sndmsg_off = 0; 13684fb66994SJarek Poplawski /* hold one ref to this page until it's full */ 13694fb66994SJarek Poplawski } else { 13704fb66994SJarek Poplawski unsigned int mlen; 13714fb66994SJarek Poplawski 13724fb66994SJarek Poplawski off = sk->sk_sndmsg_off; 13734fb66994SJarek Poplawski mlen = PAGE_SIZE - off; 13744fb66994SJarek Poplawski if (mlen < 64 && mlen < *len) { 13754fb66994SJarek Poplawski put_page(p); 13764fb66994SJarek Poplawski goto new_page; 13774fb66994SJarek Poplawski } 13784fb66994SJarek Poplawski 13794fb66994SJarek Poplawski *len = min_t(unsigned int, *len, mlen); 13804fb66994SJarek Poplawski } 13814fb66994SJarek Poplawski 13824fb66994SJarek Poplawski memcpy(page_address(p) + off, page_address(page) + *offset, *len); 13834fb66994SJarek Poplawski sk->sk_sndmsg_off += *len; 13844fb66994SJarek Poplawski *offset = off; 13854fb66994SJarek Poplawski get_page(p); 13868b9d3728SJarek Poplawski 13878b9d3728SJarek Poplawski return p; 13889c55e01cSJens Axboe } 13899c55e01cSJens Axboe 13909c55e01cSJens Axboe /* 13919c55e01cSJens Axboe * Fill page/offset/length into spd, if it can hold more pages. 13929c55e01cSJens Axboe */ 13939c55e01cSJens Axboe static inline int spd_fill_page(struct splice_pipe_desc *spd, struct page *page, 13944fb66994SJarek Poplawski unsigned int *len, unsigned int offset, 13958b9d3728SJarek Poplawski struct sk_buff *skb, int linear) 13969c55e01cSJens Axboe { 13979c55e01cSJens Axboe if (unlikely(spd->nr_pages == PIPE_BUFFERS)) 13989c55e01cSJens Axboe return 1; 13999c55e01cSJens Axboe 14008b9d3728SJarek Poplawski if (linear) { 14014fb66994SJarek Poplawski page = linear_to_page(page, len, &offset, skb); 14028b9d3728SJarek Poplawski if (!page) 14038b9d3728SJarek Poplawski return 1; 14048b9d3728SJarek Poplawski } else 14058b9d3728SJarek Poplawski get_page(page); 14068b9d3728SJarek Poplawski 14079c55e01cSJens Axboe spd->pages[spd->nr_pages] = page; 14084fb66994SJarek Poplawski spd->partial[spd->nr_pages].len = *len; 14099c55e01cSJens Axboe spd->partial[spd->nr_pages].offset = offset; 14109c55e01cSJens Axboe spd->nr_pages++; 14118b9d3728SJarek Poplawski 14129c55e01cSJens Axboe return 0; 14139c55e01cSJens Axboe } 14149c55e01cSJens Axboe 14152870c43dSOctavian Purdila static inline void __segment_seek(struct page **page, unsigned int *poff, 14162870c43dSOctavian Purdila unsigned int *plen, unsigned int off) 14172870c43dSOctavian Purdila { 1418ce3dd395SJarek Poplawski unsigned long n; 1419ce3dd395SJarek Poplawski 14202870c43dSOctavian Purdila *poff += off; 1421ce3dd395SJarek Poplawski n = *poff / PAGE_SIZE; 1422ce3dd395SJarek Poplawski if (n) 1423ce3dd395SJarek Poplawski *page = nth_page(*page, n); 1424ce3dd395SJarek Poplawski 14252870c43dSOctavian Purdila *poff = *poff % PAGE_SIZE; 14262870c43dSOctavian Purdila *plen -= off; 14272870c43dSOctavian Purdila } 14282870c43dSOctavian Purdila 14292870c43dSOctavian Purdila static inline int __splice_segment(struct page *page, unsigned int poff, 14302870c43dSOctavian Purdila unsigned int plen, unsigned int *off, 14312870c43dSOctavian Purdila unsigned int *len, struct sk_buff *skb, 14328b9d3728SJarek Poplawski struct splice_pipe_desc *spd, int linear) 14339c55e01cSJens Axboe { 14342870c43dSOctavian Purdila if (!*len) 14352870c43dSOctavian Purdila return 1; 14369c55e01cSJens Axboe 14372870c43dSOctavian Purdila /* skip this segment if already processed */ 14382870c43dSOctavian Purdila if (*off >= plen) { 14392870c43dSOctavian Purdila *off -= plen; 14402870c43dSOctavian Purdila return 0; 14412870c43dSOctavian Purdila } 14422870c43dSOctavian Purdila 14432870c43dSOctavian Purdila /* ignore any bits we already processed */ 14442870c43dSOctavian Purdila if (*off) { 14452870c43dSOctavian Purdila __segment_seek(&page, &poff, &plen, *off); 14462870c43dSOctavian Purdila *off = 0; 14472870c43dSOctavian Purdila } 14482870c43dSOctavian Purdila 14492870c43dSOctavian Purdila do { 14502870c43dSOctavian Purdila unsigned int flen = min(*len, plen); 14512870c43dSOctavian Purdila 14522870c43dSOctavian Purdila /* the linear region may spread across several pages */ 14532870c43dSOctavian Purdila flen = min_t(unsigned int, flen, PAGE_SIZE - poff); 14542870c43dSOctavian Purdila 14554fb66994SJarek Poplawski if (spd_fill_page(spd, page, &flen, poff, skb, linear)) 14562870c43dSOctavian Purdila return 1; 14572870c43dSOctavian Purdila 14582870c43dSOctavian Purdila __segment_seek(&page, &poff, &plen, flen); 14592870c43dSOctavian Purdila *len -= flen; 14602870c43dSOctavian Purdila 14612870c43dSOctavian Purdila } while (*len && plen); 14622870c43dSOctavian Purdila 14632870c43dSOctavian Purdila return 0; 1464db43a282SOctavian Purdila } 14659c55e01cSJens Axboe 14669c55e01cSJens Axboe /* 14672870c43dSOctavian Purdila * Map linear and fragment data from the skb to spd. It reports failure if the 14682870c43dSOctavian Purdila * pipe is full or if we already spliced the requested length. 14699c55e01cSJens Axboe */ 14707b1c65faSHarvey Harrison static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, 14712870c43dSOctavian Purdila unsigned int *len, 14722870c43dSOctavian Purdila struct splice_pipe_desc *spd) 14732870c43dSOctavian Purdila { 14742870c43dSOctavian Purdila int seg; 14759c55e01cSJens Axboe 14769c55e01cSJens Axboe /* 14772870c43dSOctavian Purdila * map the linear part 14789c55e01cSJens Axboe */ 14792870c43dSOctavian Purdila if (__splice_segment(virt_to_page(skb->data), 14802870c43dSOctavian Purdila (unsigned long) skb->data & (PAGE_SIZE - 1), 14812870c43dSOctavian Purdila skb_headlen(skb), 14828b9d3728SJarek Poplawski offset, len, skb, spd, 1)) 14832870c43dSOctavian Purdila return 1; 14849c55e01cSJens Axboe 14859c55e01cSJens Axboe /* 14869c55e01cSJens Axboe * then map the fragments 14879c55e01cSJens Axboe */ 14889c55e01cSJens Axboe for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { 14899c55e01cSJens Axboe const skb_frag_t *f = &skb_shinfo(skb)->frags[seg]; 14909c55e01cSJens Axboe 14912870c43dSOctavian Purdila if (__splice_segment(f->page, f->page_offset, f->size, 14928b9d3728SJarek Poplawski offset, len, skb, spd, 0)) 14932870c43dSOctavian Purdila return 1; 14949c55e01cSJens Axboe } 14959c55e01cSJens Axboe 14969c55e01cSJens Axboe return 0; 14979c55e01cSJens Axboe } 14989c55e01cSJens Axboe 14999c55e01cSJens Axboe /* 15009c55e01cSJens Axboe * Map data from the skb to a pipe. Should handle both the linear part, 15019c55e01cSJens Axboe * the fragments, and the frag list. It does NOT handle frag lists within 15029c55e01cSJens Axboe * the frag list, if such a thing exists. We'd probably need to recurse to 15039c55e01cSJens Axboe * handle that cleanly. 15049c55e01cSJens Axboe */ 15058b9d3728SJarek Poplawski int skb_splice_bits(struct sk_buff *skb, unsigned int offset, 15069c55e01cSJens Axboe struct pipe_inode_info *pipe, unsigned int tlen, 15079c55e01cSJens Axboe unsigned int flags) 15089c55e01cSJens Axboe { 15099c55e01cSJens Axboe struct partial_page partial[PIPE_BUFFERS]; 15109c55e01cSJens Axboe struct page *pages[PIPE_BUFFERS]; 15119c55e01cSJens Axboe struct splice_pipe_desc spd = { 15129c55e01cSJens Axboe .pages = pages, 15139c55e01cSJens Axboe .partial = partial, 15149c55e01cSJens Axboe .flags = flags, 15159c55e01cSJens Axboe .ops = &sock_pipe_buf_ops, 15169c55e01cSJens Axboe .spd_release = sock_spd_release, 15179c55e01cSJens Axboe }; 15189c55e01cSJens Axboe 15199c55e01cSJens Axboe /* 15209c55e01cSJens Axboe * __skb_splice_bits() only fails if the output has no room left, 15219c55e01cSJens Axboe * so no point in going over the frag_list for the error case. 15229c55e01cSJens Axboe */ 15239c55e01cSJens Axboe if (__skb_splice_bits(skb, &offset, &tlen, &spd)) 15249c55e01cSJens Axboe goto done; 15259c55e01cSJens Axboe else if (!tlen) 15269c55e01cSJens Axboe goto done; 15279c55e01cSJens Axboe 15289c55e01cSJens Axboe /* 15299c55e01cSJens Axboe * now see if we have a frag_list to map 15309c55e01cSJens Axboe */ 15319c55e01cSJens Axboe if (skb_shinfo(skb)->frag_list) { 15329c55e01cSJens Axboe struct sk_buff *list = skb_shinfo(skb)->frag_list; 15339c55e01cSJens Axboe 15349c55e01cSJens Axboe for (; list && tlen; list = list->next) { 15359c55e01cSJens Axboe if (__skb_splice_bits(list, &offset, &tlen, &spd)) 15369c55e01cSJens Axboe break; 15379c55e01cSJens Axboe } 15389c55e01cSJens Axboe } 15399c55e01cSJens Axboe 15409c55e01cSJens Axboe done: 15419c55e01cSJens Axboe if (spd.nr_pages) { 15428b9d3728SJarek Poplawski struct sock *sk = skb->sk; 15439c55e01cSJens Axboe int ret; 15449c55e01cSJens Axboe 15459c55e01cSJens Axboe /* 15469c55e01cSJens Axboe * Drop the socket lock, otherwise we have reverse 15479c55e01cSJens Axboe * locking dependencies between sk_lock and i_mutex 15489c55e01cSJens Axboe * here as compared to sendfile(). We enter here 15499c55e01cSJens Axboe * with the socket lock held, and splice_to_pipe() will 15509c55e01cSJens Axboe * grab the pipe inode lock. For sendfile() emulation, 15519c55e01cSJens Axboe * we call into ->sendpage() with the i_mutex lock held 15529c55e01cSJens Axboe * and networking will grab the socket lock. 15539c55e01cSJens Axboe */ 1554293ad604SOctavian Purdila release_sock(sk); 15559c55e01cSJens Axboe ret = splice_to_pipe(pipe, &spd); 1556293ad604SOctavian Purdila lock_sock(sk); 15579c55e01cSJens Axboe return ret; 15589c55e01cSJens Axboe } 15599c55e01cSJens Axboe 15609c55e01cSJens Axboe return 0; 15619c55e01cSJens Axboe } 15629c55e01cSJens Axboe 1563357b40a1SHerbert Xu /** 1564357b40a1SHerbert Xu * skb_store_bits - store bits from kernel buffer to skb 1565357b40a1SHerbert Xu * @skb: destination buffer 1566357b40a1SHerbert Xu * @offset: offset in destination 1567357b40a1SHerbert Xu * @from: source buffer 1568357b40a1SHerbert Xu * @len: number of bytes to copy 1569357b40a1SHerbert Xu * 1570357b40a1SHerbert Xu * Copy the specified number of bytes from the source buffer to the 1571357b40a1SHerbert Xu * destination skb. This function handles all the messy bits of 1572357b40a1SHerbert Xu * traversing fragment lists and such. 1573357b40a1SHerbert Xu */ 1574357b40a1SHerbert Xu 15750c6fcc8aSStephen Hemminger int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len) 1576357b40a1SHerbert Xu { 1577357b40a1SHerbert Xu int i, copy; 15781a028e50SDavid S. Miller int start = skb_headlen(skb); 1579357b40a1SHerbert Xu 1580357b40a1SHerbert Xu if (offset > (int)skb->len - len) 1581357b40a1SHerbert Xu goto fault; 1582357b40a1SHerbert Xu 15831a028e50SDavid S. Miller if ((copy = start - offset) > 0) { 1584357b40a1SHerbert Xu if (copy > len) 1585357b40a1SHerbert Xu copy = len; 158627d7ff46SArnaldo Carvalho de Melo skb_copy_to_linear_data_offset(skb, offset, from, copy); 1587357b40a1SHerbert Xu if ((len -= copy) == 0) 1588357b40a1SHerbert Xu return 0; 1589357b40a1SHerbert Xu offset += copy; 1590357b40a1SHerbert Xu from += copy; 1591357b40a1SHerbert Xu } 1592357b40a1SHerbert Xu 1593357b40a1SHerbert Xu for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 1594357b40a1SHerbert Xu skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 15951a028e50SDavid S. Miller int end; 1596357b40a1SHerbert Xu 1597547b792cSIlpo Järvinen WARN_ON(start > offset + len); 15981a028e50SDavid S. Miller 15991a028e50SDavid S. Miller end = start + frag->size; 1600357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1601357b40a1SHerbert Xu u8 *vaddr; 1602357b40a1SHerbert Xu 1603357b40a1SHerbert Xu if (copy > len) 1604357b40a1SHerbert Xu copy = len; 1605357b40a1SHerbert Xu 1606357b40a1SHerbert Xu vaddr = kmap_skb_frag(frag); 16071a028e50SDavid S. Miller memcpy(vaddr + frag->page_offset + offset - start, 16081a028e50SDavid S. Miller from, copy); 1609357b40a1SHerbert Xu kunmap_skb_frag(vaddr); 1610357b40a1SHerbert Xu 1611357b40a1SHerbert Xu if ((len -= copy) == 0) 1612357b40a1SHerbert Xu return 0; 1613357b40a1SHerbert Xu offset += copy; 1614357b40a1SHerbert Xu from += copy; 1615357b40a1SHerbert Xu } 16161a028e50SDavid S. Miller start = end; 1617357b40a1SHerbert Xu } 1618357b40a1SHerbert Xu 1619357b40a1SHerbert Xu if (skb_shinfo(skb)->frag_list) { 1620357b40a1SHerbert Xu struct sk_buff *list = skb_shinfo(skb)->frag_list; 1621357b40a1SHerbert Xu 1622357b40a1SHerbert Xu for (; list; list = list->next) { 16231a028e50SDavid S. Miller int end; 1624357b40a1SHerbert Xu 1625547b792cSIlpo Järvinen WARN_ON(start > offset + len); 16261a028e50SDavid S. Miller 16271a028e50SDavid S. Miller end = start + list->len; 1628357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1629357b40a1SHerbert Xu if (copy > len) 1630357b40a1SHerbert Xu copy = len; 16311a028e50SDavid S. Miller if (skb_store_bits(list, offset - start, 16321a028e50SDavid S. Miller from, copy)) 1633357b40a1SHerbert Xu goto fault; 1634357b40a1SHerbert Xu if ((len -= copy) == 0) 1635357b40a1SHerbert Xu return 0; 1636357b40a1SHerbert Xu offset += copy; 1637357b40a1SHerbert Xu from += copy; 1638357b40a1SHerbert Xu } 16391a028e50SDavid S. Miller start = end; 1640357b40a1SHerbert Xu } 1641357b40a1SHerbert Xu } 1642357b40a1SHerbert Xu if (!len) 1643357b40a1SHerbert Xu return 0; 1644357b40a1SHerbert Xu 1645357b40a1SHerbert Xu fault: 1646357b40a1SHerbert Xu return -EFAULT; 1647357b40a1SHerbert Xu } 1648357b40a1SHerbert Xu EXPORT_SYMBOL(skb_store_bits); 1649357b40a1SHerbert Xu 16501da177e4SLinus Torvalds /* Checksum skb data. */ 16511da177e4SLinus Torvalds 16522bbbc868SAl Viro __wsum skb_checksum(const struct sk_buff *skb, int offset, 16532bbbc868SAl Viro int len, __wsum csum) 16541da177e4SLinus Torvalds { 16551a028e50SDavid S. Miller int start = skb_headlen(skb); 16561a028e50SDavid S. Miller int i, copy = start - offset; 16571da177e4SLinus Torvalds int pos = 0; 16581da177e4SLinus Torvalds 16591da177e4SLinus Torvalds /* Checksum header. */ 16601da177e4SLinus Torvalds if (copy > 0) { 16611da177e4SLinus Torvalds if (copy > len) 16621da177e4SLinus Torvalds copy = len; 16631da177e4SLinus Torvalds csum = csum_partial(skb->data + offset, copy, csum); 16641da177e4SLinus Torvalds if ((len -= copy) == 0) 16651da177e4SLinus Torvalds return csum; 16661da177e4SLinus Torvalds offset += copy; 16671da177e4SLinus Torvalds pos = copy; 16681da177e4SLinus Torvalds } 16691da177e4SLinus Torvalds 16701da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 16711a028e50SDavid S. Miller int end; 16721da177e4SLinus Torvalds 1673547b792cSIlpo Järvinen WARN_ON(start > offset + len); 16741a028e50SDavid S. Miller 16751a028e50SDavid S. Miller end = start + skb_shinfo(skb)->frags[i].size; 16761da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 167744bb9363SAl Viro __wsum csum2; 16781da177e4SLinus Torvalds u8 *vaddr; 16791da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 16801da177e4SLinus Torvalds 16811da177e4SLinus Torvalds if (copy > len) 16821da177e4SLinus Torvalds copy = len; 16831da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 16841a028e50SDavid S. Miller csum2 = csum_partial(vaddr + frag->page_offset + 16851a028e50SDavid S. Miller offset - start, copy, 0); 16861da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 16871da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 16881da177e4SLinus Torvalds if (!(len -= copy)) 16891da177e4SLinus Torvalds return csum; 16901da177e4SLinus Torvalds offset += copy; 16911da177e4SLinus Torvalds pos += copy; 16921da177e4SLinus Torvalds } 16931a028e50SDavid S. Miller start = end; 16941da177e4SLinus Torvalds } 16951da177e4SLinus Torvalds 16961da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 16971da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 16981da177e4SLinus Torvalds 16991da177e4SLinus Torvalds for (; list; list = list->next) { 17001a028e50SDavid S. Miller int end; 17011da177e4SLinus Torvalds 1702547b792cSIlpo Järvinen WARN_ON(start > offset + len); 17031a028e50SDavid S. Miller 17041a028e50SDavid S. Miller end = start + list->len; 17051da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 17065f92a738SAl Viro __wsum csum2; 17071da177e4SLinus Torvalds if (copy > len) 17081da177e4SLinus Torvalds copy = len; 17091a028e50SDavid S. Miller csum2 = skb_checksum(list, offset - start, 17101a028e50SDavid S. Miller copy, 0); 17111da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 17121da177e4SLinus Torvalds if ((len -= copy) == 0) 17131da177e4SLinus Torvalds return csum; 17141da177e4SLinus Torvalds offset += copy; 17151da177e4SLinus Torvalds pos += copy; 17161da177e4SLinus Torvalds } 17171a028e50SDavid S. Miller start = end; 17181da177e4SLinus Torvalds } 17191da177e4SLinus Torvalds } 172009a62660SKris Katterjohn BUG_ON(len); 17211da177e4SLinus Torvalds 17221da177e4SLinus Torvalds return csum; 17231da177e4SLinus Torvalds } 1724b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_checksum); 17251da177e4SLinus Torvalds 17261da177e4SLinus Torvalds /* Both of above in one bottle. */ 17271da177e4SLinus Torvalds 172881d77662SAl Viro __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 172981d77662SAl Viro u8 *to, int len, __wsum csum) 17301da177e4SLinus Torvalds { 17311a028e50SDavid S. Miller int start = skb_headlen(skb); 17321a028e50SDavid S. Miller int i, copy = start - offset; 17331da177e4SLinus Torvalds int pos = 0; 17341da177e4SLinus Torvalds 17351da177e4SLinus Torvalds /* Copy header. */ 17361da177e4SLinus Torvalds if (copy > 0) { 17371da177e4SLinus Torvalds if (copy > len) 17381da177e4SLinus Torvalds copy = len; 17391da177e4SLinus Torvalds csum = csum_partial_copy_nocheck(skb->data + offset, to, 17401da177e4SLinus Torvalds copy, csum); 17411da177e4SLinus Torvalds if ((len -= copy) == 0) 17421da177e4SLinus Torvalds return csum; 17431da177e4SLinus Torvalds offset += copy; 17441da177e4SLinus Torvalds to += copy; 17451da177e4SLinus Torvalds pos = copy; 17461da177e4SLinus Torvalds } 17471da177e4SLinus Torvalds 17481da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 17491a028e50SDavid S. Miller int end; 17501da177e4SLinus Torvalds 1751547b792cSIlpo Järvinen WARN_ON(start > offset + len); 17521a028e50SDavid S. Miller 17531a028e50SDavid S. Miller end = start + skb_shinfo(skb)->frags[i].size; 17541da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 17555084205fSAl Viro __wsum csum2; 17561da177e4SLinus Torvalds u8 *vaddr; 17571da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 17581da177e4SLinus Torvalds 17591da177e4SLinus Torvalds if (copy > len) 17601da177e4SLinus Torvalds copy = len; 17611da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 17621da177e4SLinus Torvalds csum2 = csum_partial_copy_nocheck(vaddr + 17631a028e50SDavid S. Miller frag->page_offset + 17641a028e50SDavid S. Miller offset - start, to, 17651a028e50SDavid S. Miller copy, 0); 17661da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 17671da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 17681da177e4SLinus Torvalds if (!(len -= copy)) 17691da177e4SLinus Torvalds return csum; 17701da177e4SLinus Torvalds offset += copy; 17711da177e4SLinus Torvalds to += copy; 17721da177e4SLinus Torvalds pos += copy; 17731da177e4SLinus Torvalds } 17741a028e50SDavid S. Miller start = end; 17751da177e4SLinus Torvalds } 17761da177e4SLinus Torvalds 17771da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 17781da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 17791da177e4SLinus Torvalds 17801da177e4SLinus Torvalds for (; list; list = list->next) { 178181d77662SAl Viro __wsum csum2; 17821a028e50SDavid S. Miller int end; 17831da177e4SLinus Torvalds 1784547b792cSIlpo Järvinen WARN_ON(start > offset + len); 17851a028e50SDavid S. Miller 17861a028e50SDavid S. Miller end = start + list->len; 17871da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 17881da177e4SLinus Torvalds if (copy > len) 17891da177e4SLinus Torvalds copy = len; 17901a028e50SDavid S. Miller csum2 = skb_copy_and_csum_bits(list, 17911a028e50SDavid S. Miller offset - start, 17921da177e4SLinus Torvalds to, copy, 0); 17931da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 17941da177e4SLinus Torvalds if ((len -= copy) == 0) 17951da177e4SLinus Torvalds return csum; 17961da177e4SLinus Torvalds offset += copy; 17971da177e4SLinus Torvalds to += copy; 17981da177e4SLinus Torvalds pos += copy; 17991da177e4SLinus Torvalds } 18001a028e50SDavid S. Miller start = end; 18011da177e4SLinus Torvalds } 18021da177e4SLinus Torvalds } 180309a62660SKris Katterjohn BUG_ON(len); 18041da177e4SLinus Torvalds return csum; 18051da177e4SLinus Torvalds } 1806b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_and_csum_bits); 18071da177e4SLinus Torvalds 18081da177e4SLinus Torvalds void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) 18091da177e4SLinus Torvalds { 1810d3bc23e7SAl Viro __wsum csum; 18111da177e4SLinus Torvalds long csstart; 18121da177e4SLinus Torvalds 181384fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) 1814663ead3bSHerbert Xu csstart = skb->csum_start - skb_headroom(skb); 18151da177e4SLinus Torvalds else 18161da177e4SLinus Torvalds csstart = skb_headlen(skb); 18171da177e4SLinus Torvalds 181809a62660SKris Katterjohn BUG_ON(csstart > skb_headlen(skb)); 18191da177e4SLinus Torvalds 1820d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data(skb, to, csstart); 18211da177e4SLinus Torvalds 18221da177e4SLinus Torvalds csum = 0; 18231da177e4SLinus Torvalds if (csstart != skb->len) 18241da177e4SLinus Torvalds csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, 18251da177e4SLinus Torvalds skb->len - csstart, 0); 18261da177e4SLinus Torvalds 182784fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) { 1828ff1dcadbSAl Viro long csstuff = csstart + skb->csum_offset; 18291da177e4SLinus Torvalds 1830d3bc23e7SAl Viro *((__sum16 *)(to + csstuff)) = csum_fold(csum); 18311da177e4SLinus Torvalds } 18321da177e4SLinus Torvalds } 1833b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_copy_and_csum_dev); 18341da177e4SLinus Torvalds 18351da177e4SLinus Torvalds /** 18361da177e4SLinus Torvalds * skb_dequeue - remove from the head of the queue 18371da177e4SLinus Torvalds * @list: list to dequeue from 18381da177e4SLinus Torvalds * 18391da177e4SLinus Torvalds * Remove the head of the list. The list lock is taken so the function 18401da177e4SLinus Torvalds * may be used safely with other locking list functions. The head item is 18411da177e4SLinus Torvalds * returned or %NULL if the list is empty. 18421da177e4SLinus Torvalds */ 18431da177e4SLinus Torvalds 18441da177e4SLinus Torvalds struct sk_buff *skb_dequeue(struct sk_buff_head *list) 18451da177e4SLinus Torvalds { 18461da177e4SLinus Torvalds unsigned long flags; 18471da177e4SLinus Torvalds struct sk_buff *result; 18481da177e4SLinus Torvalds 18491da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 18501da177e4SLinus Torvalds result = __skb_dequeue(list); 18511da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 18521da177e4SLinus Torvalds return result; 18531da177e4SLinus Torvalds } 1854b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_dequeue); 18551da177e4SLinus Torvalds 18561da177e4SLinus Torvalds /** 18571da177e4SLinus Torvalds * skb_dequeue_tail - remove from the tail of the queue 18581da177e4SLinus Torvalds * @list: list to dequeue from 18591da177e4SLinus Torvalds * 18601da177e4SLinus Torvalds * Remove the tail of the list. The list lock is taken so the function 18611da177e4SLinus Torvalds * may be used safely with other locking list functions. The tail item is 18621da177e4SLinus Torvalds * returned or %NULL if the list is empty. 18631da177e4SLinus Torvalds */ 18641da177e4SLinus Torvalds struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) 18651da177e4SLinus Torvalds { 18661da177e4SLinus Torvalds unsigned long flags; 18671da177e4SLinus Torvalds struct sk_buff *result; 18681da177e4SLinus Torvalds 18691da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 18701da177e4SLinus Torvalds result = __skb_dequeue_tail(list); 18711da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 18721da177e4SLinus Torvalds return result; 18731da177e4SLinus Torvalds } 1874b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_dequeue_tail); 18751da177e4SLinus Torvalds 18761da177e4SLinus Torvalds /** 18771da177e4SLinus Torvalds * skb_queue_purge - empty a list 18781da177e4SLinus Torvalds * @list: list to empty 18791da177e4SLinus Torvalds * 18801da177e4SLinus Torvalds * Delete all buffers on an &sk_buff list. Each buffer is removed from 18811da177e4SLinus Torvalds * the list and one reference dropped. This function takes the list 18821da177e4SLinus Torvalds * lock and is atomic with respect to other list locking functions. 18831da177e4SLinus Torvalds */ 18841da177e4SLinus Torvalds void skb_queue_purge(struct sk_buff_head *list) 18851da177e4SLinus Torvalds { 18861da177e4SLinus Torvalds struct sk_buff *skb; 18871da177e4SLinus Torvalds while ((skb = skb_dequeue(list)) != NULL) 18881da177e4SLinus Torvalds kfree_skb(skb); 18891da177e4SLinus Torvalds } 1890b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_purge); 18911da177e4SLinus Torvalds 18921da177e4SLinus Torvalds /** 18931da177e4SLinus Torvalds * skb_queue_head - queue a buffer at the list head 18941da177e4SLinus Torvalds * @list: list to use 18951da177e4SLinus Torvalds * @newsk: buffer to queue 18961da177e4SLinus Torvalds * 18971da177e4SLinus Torvalds * Queue a buffer at the start of the list. This function takes the 18981da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 18991da177e4SLinus Torvalds * safely. 19001da177e4SLinus Torvalds * 19011da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 19021da177e4SLinus Torvalds */ 19031da177e4SLinus Torvalds void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) 19041da177e4SLinus Torvalds { 19051da177e4SLinus Torvalds unsigned long flags; 19061da177e4SLinus Torvalds 19071da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 19081da177e4SLinus Torvalds __skb_queue_head(list, newsk); 19091da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 19101da177e4SLinus Torvalds } 1911b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_head); 19121da177e4SLinus Torvalds 19131da177e4SLinus Torvalds /** 19141da177e4SLinus Torvalds * skb_queue_tail - queue a buffer at the list tail 19151da177e4SLinus Torvalds * @list: list to use 19161da177e4SLinus Torvalds * @newsk: buffer to queue 19171da177e4SLinus Torvalds * 19181da177e4SLinus Torvalds * Queue a buffer at the tail of the list. This function takes the 19191da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 19201da177e4SLinus Torvalds * safely. 19211da177e4SLinus Torvalds * 19221da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 19231da177e4SLinus Torvalds */ 19241da177e4SLinus Torvalds void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) 19251da177e4SLinus Torvalds { 19261da177e4SLinus Torvalds unsigned long flags; 19271da177e4SLinus Torvalds 19281da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 19291da177e4SLinus Torvalds __skb_queue_tail(list, newsk); 19301da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 19311da177e4SLinus Torvalds } 1932b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_queue_tail); 19338728b834SDavid S. Miller 19341da177e4SLinus Torvalds /** 19351da177e4SLinus Torvalds * skb_unlink - remove a buffer from a list 19361da177e4SLinus Torvalds * @skb: buffer to remove 19378728b834SDavid S. Miller * @list: list to use 19381da177e4SLinus Torvalds * 19398728b834SDavid S. Miller * Remove a packet from a list. The list locks are taken and this 19408728b834SDavid S. Miller * function is atomic with respect to other list locked calls 19411da177e4SLinus Torvalds * 19428728b834SDavid S. Miller * You must know what list the SKB is on. 19431da177e4SLinus Torvalds */ 19448728b834SDavid S. Miller void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 19451da177e4SLinus Torvalds { 19461da177e4SLinus Torvalds unsigned long flags; 19471da177e4SLinus Torvalds 19481da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 19498728b834SDavid S. Miller __skb_unlink(skb, list); 19501da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 19511da177e4SLinus Torvalds } 1952b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_unlink); 19531da177e4SLinus Torvalds 19541da177e4SLinus Torvalds /** 19551da177e4SLinus Torvalds * skb_append - append a buffer 19561da177e4SLinus Torvalds * @old: buffer to insert after 19571da177e4SLinus Torvalds * @newsk: buffer to insert 19588728b834SDavid S. Miller * @list: list to use 19591da177e4SLinus Torvalds * 19601da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 19611da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls. 19621da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 19631da177e4SLinus Torvalds */ 19648728b834SDavid S. Miller void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 19651da177e4SLinus Torvalds { 19661da177e4SLinus Torvalds unsigned long flags; 19671da177e4SLinus Torvalds 19688728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 19697de6c033SGerrit Renker __skb_queue_after(list, old, newsk); 19708728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 19711da177e4SLinus Torvalds } 1972b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_append); 19731da177e4SLinus Torvalds 19741da177e4SLinus Torvalds /** 19751da177e4SLinus Torvalds * skb_insert - insert a buffer 19761da177e4SLinus Torvalds * @old: buffer to insert before 19771da177e4SLinus Torvalds * @newsk: buffer to insert 19788728b834SDavid S. Miller * @list: list to use 19791da177e4SLinus Torvalds * 19808728b834SDavid S. Miller * Place a packet before a given packet in a list. The list locks are 19818728b834SDavid S. Miller * taken and this function is atomic with respect to other list locked 19828728b834SDavid S. Miller * calls. 19838728b834SDavid S. Miller * 19841da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 19851da177e4SLinus Torvalds */ 19868728b834SDavid S. Miller void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 19871da177e4SLinus Torvalds { 19881da177e4SLinus Torvalds unsigned long flags; 19891da177e4SLinus Torvalds 19908728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 19918728b834SDavid S. Miller __skb_insert(newsk, old->prev, old, list); 19928728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 19931da177e4SLinus Torvalds } 1994b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_insert); 19951da177e4SLinus Torvalds 19961da177e4SLinus Torvalds static inline void skb_split_inside_header(struct sk_buff *skb, 19971da177e4SLinus Torvalds struct sk_buff* skb1, 19981da177e4SLinus Torvalds const u32 len, const int pos) 19991da177e4SLinus Torvalds { 20001da177e4SLinus Torvalds int i; 20011da177e4SLinus Torvalds 2002d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len), 2003d626f62bSArnaldo Carvalho de Melo pos - len); 20041da177e4SLinus Torvalds /* And move data appendix as is. */ 20051da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 20061da177e4SLinus Torvalds skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; 20071da177e4SLinus Torvalds 20081da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; 20091da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 20101da177e4SLinus Torvalds skb1->data_len = skb->data_len; 20111da177e4SLinus Torvalds skb1->len += skb1->data_len; 20121da177e4SLinus Torvalds skb->data_len = 0; 20131da177e4SLinus Torvalds skb->len = len; 201427a884dcSArnaldo Carvalho de Melo skb_set_tail_pointer(skb, len); 20151da177e4SLinus Torvalds } 20161da177e4SLinus Torvalds 20171da177e4SLinus Torvalds static inline void skb_split_no_header(struct sk_buff *skb, 20181da177e4SLinus Torvalds struct sk_buff* skb1, 20191da177e4SLinus Torvalds const u32 len, int pos) 20201da177e4SLinus Torvalds { 20211da177e4SLinus Torvalds int i, k = 0; 20221da177e4SLinus Torvalds const int nfrags = skb_shinfo(skb)->nr_frags; 20231da177e4SLinus Torvalds 20241da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 20251da177e4SLinus Torvalds skb1->len = skb1->data_len = skb->len - len; 20261da177e4SLinus Torvalds skb->len = len; 20271da177e4SLinus Torvalds skb->data_len = len - pos; 20281da177e4SLinus Torvalds 20291da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 20301da177e4SLinus Torvalds int size = skb_shinfo(skb)->frags[i].size; 20311da177e4SLinus Torvalds 20321da177e4SLinus Torvalds if (pos + size > len) { 20331da177e4SLinus Torvalds skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; 20341da177e4SLinus Torvalds 20351da177e4SLinus Torvalds if (pos < len) { 20361da177e4SLinus Torvalds /* Split frag. 20371da177e4SLinus Torvalds * We have two variants in this case: 20381da177e4SLinus Torvalds * 1. Move all the frag to the second 20391da177e4SLinus Torvalds * part, if it is possible. F.e. 20401da177e4SLinus Torvalds * this approach is mandatory for TUX, 20411da177e4SLinus Torvalds * where splitting is expensive. 20421da177e4SLinus Torvalds * 2. Split is accurately. We make this. 20431da177e4SLinus Torvalds */ 20441da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 20451da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].page_offset += len - pos; 20461da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].size -= len - pos; 20471da177e4SLinus Torvalds skb_shinfo(skb)->frags[i].size = len - pos; 20481da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 20491da177e4SLinus Torvalds } 20501da177e4SLinus Torvalds k++; 20511da177e4SLinus Torvalds } else 20521da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 20531da177e4SLinus Torvalds pos += size; 20541da177e4SLinus Torvalds } 20551da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = k; 20561da177e4SLinus Torvalds } 20571da177e4SLinus Torvalds 20581da177e4SLinus Torvalds /** 20591da177e4SLinus Torvalds * skb_split - Split fragmented skb to two parts at length len. 20601da177e4SLinus Torvalds * @skb: the buffer to split 20611da177e4SLinus Torvalds * @skb1: the buffer to receive the second part 20621da177e4SLinus Torvalds * @len: new length for skb 20631da177e4SLinus Torvalds */ 20641da177e4SLinus Torvalds void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) 20651da177e4SLinus Torvalds { 20661da177e4SLinus Torvalds int pos = skb_headlen(skb); 20671da177e4SLinus Torvalds 20681da177e4SLinus Torvalds if (len < pos) /* Split line is inside header. */ 20691da177e4SLinus Torvalds skb_split_inside_header(skb, skb1, len, pos); 20701da177e4SLinus Torvalds else /* Second chunk has no header, nothing to copy. */ 20711da177e4SLinus Torvalds skb_split_no_header(skb, skb1, len, pos); 20721da177e4SLinus Torvalds } 2073b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_split); 20741da177e4SLinus Torvalds 20759f782db3SIlpo Järvinen /* Shifting from/to a cloned skb is a no-go. 20769f782db3SIlpo Järvinen * 20779f782db3SIlpo Järvinen * Caller cannot keep skb_shinfo related pointers past calling here! 20789f782db3SIlpo Järvinen */ 2079832d11c5SIlpo Järvinen static int skb_prepare_for_shift(struct sk_buff *skb) 2080832d11c5SIlpo Järvinen { 20810ace2856SIlpo Järvinen return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC); 2082832d11c5SIlpo Järvinen } 2083832d11c5SIlpo Järvinen 2084832d11c5SIlpo Järvinen /** 2085832d11c5SIlpo Järvinen * skb_shift - Shifts paged data partially from skb to another 2086832d11c5SIlpo Järvinen * @tgt: buffer into which tail data gets added 2087832d11c5SIlpo Järvinen * @skb: buffer from which the paged data comes from 2088832d11c5SIlpo Järvinen * @shiftlen: shift up to this many bytes 2089832d11c5SIlpo Järvinen * 2090832d11c5SIlpo Järvinen * Attempts to shift up to shiftlen worth of bytes, which may be less than 2091832d11c5SIlpo Järvinen * the length of the skb, from tgt to skb. Returns number bytes shifted. 2092832d11c5SIlpo Järvinen * It's up to caller to free skb if everything was shifted. 2093832d11c5SIlpo Järvinen * 2094832d11c5SIlpo Järvinen * If @tgt runs out of frags, the whole operation is aborted. 2095832d11c5SIlpo Järvinen * 2096832d11c5SIlpo Järvinen * Skb cannot include anything else but paged data while tgt is allowed 2097832d11c5SIlpo Järvinen * to have non-paged data as well. 2098832d11c5SIlpo Järvinen * 2099832d11c5SIlpo Järvinen * TODO: full sized shift could be optimized but that would need 2100832d11c5SIlpo Järvinen * specialized skb free'er to handle frags without up-to-date nr_frags. 2101832d11c5SIlpo Järvinen */ 2102832d11c5SIlpo Järvinen int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) 2103832d11c5SIlpo Järvinen { 2104832d11c5SIlpo Järvinen int from, to, merge, todo; 2105832d11c5SIlpo Järvinen struct skb_frag_struct *fragfrom, *fragto; 2106832d11c5SIlpo Järvinen 2107832d11c5SIlpo Järvinen BUG_ON(shiftlen > skb->len); 2108832d11c5SIlpo Järvinen BUG_ON(skb_headlen(skb)); /* Would corrupt stream */ 2109832d11c5SIlpo Järvinen 2110832d11c5SIlpo Järvinen todo = shiftlen; 2111832d11c5SIlpo Järvinen from = 0; 2112832d11c5SIlpo Järvinen to = skb_shinfo(tgt)->nr_frags; 2113832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 2114832d11c5SIlpo Järvinen 2115832d11c5SIlpo Järvinen /* Actual merge is delayed until the point when we know we can 2116832d11c5SIlpo Järvinen * commit all, so that we don't have to undo partial changes 2117832d11c5SIlpo Järvinen */ 2118832d11c5SIlpo Järvinen if (!to || 2119832d11c5SIlpo Järvinen !skb_can_coalesce(tgt, to, fragfrom->page, fragfrom->page_offset)) { 2120832d11c5SIlpo Järvinen merge = -1; 2121832d11c5SIlpo Järvinen } else { 2122832d11c5SIlpo Järvinen merge = to - 1; 2123832d11c5SIlpo Järvinen 2124832d11c5SIlpo Järvinen todo -= fragfrom->size; 2125832d11c5SIlpo Järvinen if (todo < 0) { 2126832d11c5SIlpo Järvinen if (skb_prepare_for_shift(skb) || 2127832d11c5SIlpo Järvinen skb_prepare_for_shift(tgt)) 2128832d11c5SIlpo Järvinen return 0; 2129832d11c5SIlpo Järvinen 21309f782db3SIlpo Järvinen /* All previous frag pointers might be stale! */ 21319f782db3SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 2132832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[merge]; 2133832d11c5SIlpo Järvinen 2134832d11c5SIlpo Järvinen fragto->size += shiftlen; 2135832d11c5SIlpo Järvinen fragfrom->size -= shiftlen; 2136832d11c5SIlpo Järvinen fragfrom->page_offset += shiftlen; 2137832d11c5SIlpo Järvinen 2138832d11c5SIlpo Järvinen goto onlymerged; 2139832d11c5SIlpo Järvinen } 2140832d11c5SIlpo Järvinen 2141832d11c5SIlpo Järvinen from++; 2142832d11c5SIlpo Järvinen } 2143832d11c5SIlpo Järvinen 2144832d11c5SIlpo Järvinen /* Skip full, not-fitting skb to avoid expensive operations */ 2145832d11c5SIlpo Järvinen if ((shiftlen == skb->len) && 2146832d11c5SIlpo Järvinen (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to)) 2147832d11c5SIlpo Järvinen return 0; 2148832d11c5SIlpo Järvinen 2149832d11c5SIlpo Järvinen if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt)) 2150832d11c5SIlpo Järvinen return 0; 2151832d11c5SIlpo Järvinen 2152832d11c5SIlpo Järvinen while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) { 2153832d11c5SIlpo Järvinen if (to == MAX_SKB_FRAGS) 2154832d11c5SIlpo Järvinen return 0; 2155832d11c5SIlpo Järvinen 2156832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[from]; 2157832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[to]; 2158832d11c5SIlpo Järvinen 2159832d11c5SIlpo Järvinen if (todo >= fragfrom->size) { 2160832d11c5SIlpo Järvinen *fragto = *fragfrom; 2161832d11c5SIlpo Järvinen todo -= fragfrom->size; 2162832d11c5SIlpo Järvinen from++; 2163832d11c5SIlpo Järvinen to++; 2164832d11c5SIlpo Järvinen 2165832d11c5SIlpo Järvinen } else { 2166832d11c5SIlpo Järvinen get_page(fragfrom->page); 2167832d11c5SIlpo Järvinen fragto->page = fragfrom->page; 2168832d11c5SIlpo Järvinen fragto->page_offset = fragfrom->page_offset; 2169832d11c5SIlpo Järvinen fragto->size = todo; 2170832d11c5SIlpo Järvinen 2171832d11c5SIlpo Järvinen fragfrom->page_offset += todo; 2172832d11c5SIlpo Järvinen fragfrom->size -= todo; 2173832d11c5SIlpo Järvinen todo = 0; 2174832d11c5SIlpo Järvinen 2175832d11c5SIlpo Järvinen to++; 2176832d11c5SIlpo Järvinen break; 2177832d11c5SIlpo Järvinen } 2178832d11c5SIlpo Järvinen } 2179832d11c5SIlpo Järvinen 2180832d11c5SIlpo Järvinen /* Ready to "commit" this state change to tgt */ 2181832d11c5SIlpo Järvinen skb_shinfo(tgt)->nr_frags = to; 2182832d11c5SIlpo Järvinen 2183832d11c5SIlpo Järvinen if (merge >= 0) { 2184832d11c5SIlpo Järvinen fragfrom = &skb_shinfo(skb)->frags[0]; 2185832d11c5SIlpo Järvinen fragto = &skb_shinfo(tgt)->frags[merge]; 2186832d11c5SIlpo Järvinen 2187832d11c5SIlpo Järvinen fragto->size += fragfrom->size; 2188832d11c5SIlpo Järvinen put_page(fragfrom->page); 2189832d11c5SIlpo Järvinen } 2190832d11c5SIlpo Järvinen 2191832d11c5SIlpo Järvinen /* Reposition in the original skb */ 2192832d11c5SIlpo Järvinen to = 0; 2193832d11c5SIlpo Järvinen while (from < skb_shinfo(skb)->nr_frags) 2194832d11c5SIlpo Järvinen skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++]; 2195832d11c5SIlpo Järvinen skb_shinfo(skb)->nr_frags = to; 2196832d11c5SIlpo Järvinen 2197832d11c5SIlpo Järvinen BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags); 2198832d11c5SIlpo Järvinen 2199832d11c5SIlpo Järvinen onlymerged: 2200832d11c5SIlpo Järvinen /* Most likely the tgt won't ever need its checksum anymore, skb on 2201832d11c5SIlpo Järvinen * the other hand might need it if it needs to be resent 2202832d11c5SIlpo Järvinen */ 2203832d11c5SIlpo Järvinen tgt->ip_summed = CHECKSUM_PARTIAL; 2204832d11c5SIlpo Järvinen skb->ip_summed = CHECKSUM_PARTIAL; 2205832d11c5SIlpo Järvinen 2206832d11c5SIlpo Järvinen /* Yak, is it really working this way? Some helper please? */ 2207832d11c5SIlpo Järvinen skb->len -= shiftlen; 2208832d11c5SIlpo Järvinen skb->data_len -= shiftlen; 2209832d11c5SIlpo Järvinen skb->truesize -= shiftlen; 2210832d11c5SIlpo Järvinen tgt->len += shiftlen; 2211832d11c5SIlpo Järvinen tgt->data_len += shiftlen; 2212832d11c5SIlpo Järvinen tgt->truesize += shiftlen; 2213832d11c5SIlpo Järvinen 2214832d11c5SIlpo Järvinen return shiftlen; 2215832d11c5SIlpo Järvinen } 2216832d11c5SIlpo Järvinen 2217677e90edSThomas Graf /** 2218677e90edSThomas Graf * skb_prepare_seq_read - Prepare a sequential read of skb data 2219677e90edSThomas Graf * @skb: the buffer to read 2220677e90edSThomas Graf * @from: lower offset of data to be read 2221677e90edSThomas Graf * @to: upper offset of data to be read 2222677e90edSThomas Graf * @st: state variable 2223677e90edSThomas Graf * 2224677e90edSThomas Graf * Initializes the specified state variable. Must be called before 2225677e90edSThomas Graf * invoking skb_seq_read() for the first time. 2226677e90edSThomas Graf */ 2227677e90edSThomas Graf void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 2228677e90edSThomas Graf unsigned int to, struct skb_seq_state *st) 2229677e90edSThomas Graf { 2230677e90edSThomas Graf st->lower_offset = from; 2231677e90edSThomas Graf st->upper_offset = to; 2232677e90edSThomas Graf st->root_skb = st->cur_skb = skb; 2233677e90edSThomas Graf st->frag_idx = st->stepped_offset = 0; 2234677e90edSThomas Graf st->frag_data = NULL; 2235677e90edSThomas Graf } 2236b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_prepare_seq_read); 2237677e90edSThomas Graf 2238677e90edSThomas Graf /** 2239677e90edSThomas Graf * skb_seq_read - Sequentially read skb data 2240677e90edSThomas Graf * @consumed: number of bytes consumed by the caller so far 2241677e90edSThomas Graf * @data: destination pointer for data to be returned 2242677e90edSThomas Graf * @st: state variable 2243677e90edSThomas Graf * 2244677e90edSThomas Graf * Reads a block of skb data at &consumed relative to the 2245677e90edSThomas Graf * lower offset specified to skb_prepare_seq_read(). Assigns 2246677e90edSThomas Graf * the head of the data block to &data and returns the length 2247677e90edSThomas Graf * of the block or 0 if the end of the skb data or the upper 2248677e90edSThomas Graf * offset has been reached. 2249677e90edSThomas Graf * 2250677e90edSThomas Graf * The caller is not required to consume all of the data 2251677e90edSThomas Graf * returned, i.e. &consumed is typically set to the number 2252677e90edSThomas Graf * of bytes already consumed and the next call to 2253677e90edSThomas Graf * skb_seq_read() will return the remaining part of the block. 2254677e90edSThomas Graf * 2255bc2cda1eSRandy Dunlap * Note 1: The size of each block of data returned can be arbitary, 2256677e90edSThomas Graf * this limitation is the cost for zerocopy seqeuental 2257677e90edSThomas Graf * reads of potentially non linear data. 2258677e90edSThomas Graf * 2259bc2cda1eSRandy Dunlap * Note 2: Fragment lists within fragments are not implemented 2260677e90edSThomas Graf * at the moment, state->root_skb could be replaced with 2261677e90edSThomas Graf * a stack for this purpose. 2262677e90edSThomas Graf */ 2263677e90edSThomas Graf unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 2264677e90edSThomas Graf struct skb_seq_state *st) 2265677e90edSThomas Graf { 2266677e90edSThomas Graf unsigned int block_limit, abs_offset = consumed + st->lower_offset; 2267677e90edSThomas Graf skb_frag_t *frag; 2268677e90edSThomas Graf 2269677e90edSThomas Graf if (unlikely(abs_offset >= st->upper_offset)) 2270677e90edSThomas Graf return 0; 2271677e90edSThomas Graf 2272677e90edSThomas Graf next_skb: 227395e3b24cSHerbert Xu block_limit = skb_headlen(st->cur_skb) + st->stepped_offset; 2274677e90edSThomas Graf 2275677e90edSThomas Graf if (abs_offset < block_limit) { 227695e3b24cSHerbert Xu *data = st->cur_skb->data + (abs_offset - st->stepped_offset); 2277677e90edSThomas Graf return block_limit - abs_offset; 2278677e90edSThomas Graf } 2279677e90edSThomas Graf 2280677e90edSThomas Graf if (st->frag_idx == 0 && !st->frag_data) 2281677e90edSThomas Graf st->stepped_offset += skb_headlen(st->cur_skb); 2282677e90edSThomas Graf 2283677e90edSThomas Graf while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { 2284677e90edSThomas Graf frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; 2285677e90edSThomas Graf block_limit = frag->size + st->stepped_offset; 2286677e90edSThomas Graf 2287677e90edSThomas Graf if (abs_offset < block_limit) { 2288677e90edSThomas Graf if (!st->frag_data) 2289677e90edSThomas Graf st->frag_data = kmap_skb_frag(frag); 2290677e90edSThomas Graf 2291677e90edSThomas Graf *data = (u8 *) st->frag_data + frag->page_offset + 2292677e90edSThomas Graf (abs_offset - st->stepped_offset); 2293677e90edSThomas Graf 2294677e90edSThomas Graf return block_limit - abs_offset; 2295677e90edSThomas Graf } 2296677e90edSThomas Graf 2297677e90edSThomas Graf if (st->frag_data) { 2298677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 2299677e90edSThomas Graf st->frag_data = NULL; 2300677e90edSThomas Graf } 2301677e90edSThomas Graf 2302677e90edSThomas Graf st->frag_idx++; 2303677e90edSThomas Graf st->stepped_offset += frag->size; 2304677e90edSThomas Graf } 2305677e90edSThomas Graf 23065b5a60daSOlaf Kirch if (st->frag_data) { 23075b5a60daSOlaf Kirch kunmap_skb_frag(st->frag_data); 23085b5a60daSOlaf Kirch st->frag_data = NULL; 23095b5a60daSOlaf Kirch } 23105b5a60daSOlaf Kirch 231171b3346dSShyam Iyer if (st->root_skb == st->cur_skb && 2312677e90edSThomas Graf skb_shinfo(st->root_skb)->frag_list) { 2313677e90edSThomas Graf st->cur_skb = skb_shinfo(st->root_skb)->frag_list; 231495e3b24cSHerbert Xu st->frag_idx = 0; 2315677e90edSThomas Graf goto next_skb; 231671b3346dSShyam Iyer } else if (st->cur_skb->next) { 231771b3346dSShyam Iyer st->cur_skb = st->cur_skb->next; 231871b3346dSShyam Iyer st->frag_idx = 0; 2319677e90edSThomas Graf goto next_skb; 2320677e90edSThomas Graf } 2321677e90edSThomas Graf 2322677e90edSThomas Graf return 0; 2323677e90edSThomas Graf } 2324b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_seq_read); 2325677e90edSThomas Graf 2326677e90edSThomas Graf /** 2327677e90edSThomas Graf * skb_abort_seq_read - Abort a sequential read of skb data 2328677e90edSThomas Graf * @st: state variable 2329677e90edSThomas Graf * 2330677e90edSThomas Graf * Must be called if skb_seq_read() was not called until it 2331677e90edSThomas Graf * returned 0. 2332677e90edSThomas Graf */ 2333677e90edSThomas Graf void skb_abort_seq_read(struct skb_seq_state *st) 2334677e90edSThomas Graf { 2335677e90edSThomas Graf if (st->frag_data) 2336677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 2337677e90edSThomas Graf } 2338b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_abort_seq_read); 2339677e90edSThomas Graf 23403fc7e8a6SThomas Graf #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) 23413fc7e8a6SThomas Graf 23423fc7e8a6SThomas Graf static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, 23433fc7e8a6SThomas Graf struct ts_config *conf, 23443fc7e8a6SThomas Graf struct ts_state *state) 23453fc7e8a6SThomas Graf { 23463fc7e8a6SThomas Graf return skb_seq_read(offset, text, TS_SKB_CB(state)); 23473fc7e8a6SThomas Graf } 23483fc7e8a6SThomas Graf 23493fc7e8a6SThomas Graf static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) 23503fc7e8a6SThomas Graf { 23513fc7e8a6SThomas Graf skb_abort_seq_read(TS_SKB_CB(state)); 23523fc7e8a6SThomas Graf } 23533fc7e8a6SThomas Graf 23543fc7e8a6SThomas Graf /** 23553fc7e8a6SThomas Graf * skb_find_text - Find a text pattern in skb data 23563fc7e8a6SThomas Graf * @skb: the buffer to look in 23573fc7e8a6SThomas Graf * @from: search offset 23583fc7e8a6SThomas Graf * @to: search limit 23593fc7e8a6SThomas Graf * @config: textsearch configuration 23603fc7e8a6SThomas Graf * @state: uninitialized textsearch state variable 23613fc7e8a6SThomas Graf * 23623fc7e8a6SThomas Graf * Finds a pattern in the skb data according to the specified 23633fc7e8a6SThomas Graf * textsearch configuration. Use textsearch_next() to retrieve 23643fc7e8a6SThomas Graf * subsequent occurrences of the pattern. Returns the offset 23653fc7e8a6SThomas Graf * to the first occurrence or UINT_MAX if no match was found. 23663fc7e8a6SThomas Graf */ 23673fc7e8a6SThomas Graf unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 23683fc7e8a6SThomas Graf unsigned int to, struct ts_config *config, 23693fc7e8a6SThomas Graf struct ts_state *state) 23703fc7e8a6SThomas Graf { 2371f72b948dSPhil Oester unsigned int ret; 2372f72b948dSPhil Oester 23733fc7e8a6SThomas Graf config->get_next_block = skb_ts_get_next_block; 23743fc7e8a6SThomas Graf config->finish = skb_ts_finish; 23753fc7e8a6SThomas Graf 23763fc7e8a6SThomas Graf skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); 23773fc7e8a6SThomas Graf 2378f72b948dSPhil Oester ret = textsearch_find(config, state); 2379f72b948dSPhil Oester return (ret <= to - from ? ret : UINT_MAX); 23803fc7e8a6SThomas Graf } 2381b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_find_text); 23823fc7e8a6SThomas Graf 2383e89e9cf5SAnanda Raju /** 2384e89e9cf5SAnanda Raju * skb_append_datato_frags: - append the user data to a skb 2385e89e9cf5SAnanda Raju * @sk: sock structure 2386e89e9cf5SAnanda Raju * @skb: skb structure to be appened with user data. 2387e89e9cf5SAnanda Raju * @getfrag: call back function to be used for getting the user data 2388e89e9cf5SAnanda Raju * @from: pointer to user message iov 2389e89e9cf5SAnanda Raju * @length: length of the iov message 2390e89e9cf5SAnanda Raju * 2391e89e9cf5SAnanda Raju * Description: This procedure append the user data in the fragment part 2392e89e9cf5SAnanda Raju * of the skb if any page alloc fails user this procedure returns -ENOMEM 2393e89e9cf5SAnanda Raju */ 2394e89e9cf5SAnanda Raju int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, 2395dab9630fSMartin Waitz int (*getfrag)(void *from, char *to, int offset, 2396e89e9cf5SAnanda Raju int len, int odd, struct sk_buff *skb), 2397e89e9cf5SAnanda Raju void *from, int length) 2398e89e9cf5SAnanda Raju { 2399e89e9cf5SAnanda Raju int frg_cnt = 0; 2400e89e9cf5SAnanda Raju skb_frag_t *frag = NULL; 2401e89e9cf5SAnanda Raju struct page *page = NULL; 2402e89e9cf5SAnanda Raju int copy, left; 2403e89e9cf5SAnanda Raju int offset = 0; 2404e89e9cf5SAnanda Raju int ret; 2405e89e9cf5SAnanda Raju 2406e89e9cf5SAnanda Raju do { 2407e89e9cf5SAnanda Raju /* Return error if we don't have space for new frag */ 2408e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 2409e89e9cf5SAnanda Raju if (frg_cnt >= MAX_SKB_FRAGS) 2410e89e9cf5SAnanda Raju return -EFAULT; 2411e89e9cf5SAnanda Raju 2412e89e9cf5SAnanda Raju /* allocate a new page for next frag */ 2413e89e9cf5SAnanda Raju page = alloc_pages(sk->sk_allocation, 0); 2414e89e9cf5SAnanda Raju 2415e89e9cf5SAnanda Raju /* If alloc_page fails just return failure and caller will 2416e89e9cf5SAnanda Raju * free previous allocated pages by doing kfree_skb() 2417e89e9cf5SAnanda Raju */ 2418e89e9cf5SAnanda Raju if (page == NULL) 2419e89e9cf5SAnanda Raju return -ENOMEM; 2420e89e9cf5SAnanda Raju 2421e89e9cf5SAnanda Raju /* initialize the next frag */ 2422e89e9cf5SAnanda Raju sk->sk_sndmsg_page = page; 2423e89e9cf5SAnanda Raju sk->sk_sndmsg_off = 0; 2424e89e9cf5SAnanda Raju skb_fill_page_desc(skb, frg_cnt, page, 0, 0); 2425e89e9cf5SAnanda Raju skb->truesize += PAGE_SIZE; 2426e89e9cf5SAnanda Raju atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 2427e89e9cf5SAnanda Raju 2428e89e9cf5SAnanda Raju /* get the new initialized frag */ 2429e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 2430e89e9cf5SAnanda Raju frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; 2431e89e9cf5SAnanda Raju 2432e89e9cf5SAnanda Raju /* copy the user data to page */ 2433e89e9cf5SAnanda Raju left = PAGE_SIZE - frag->page_offset; 2434e89e9cf5SAnanda Raju copy = (length > left)? left : length; 2435e89e9cf5SAnanda Raju 2436e89e9cf5SAnanda Raju ret = getfrag(from, (page_address(frag->page) + 2437e89e9cf5SAnanda Raju frag->page_offset + frag->size), 2438e89e9cf5SAnanda Raju offset, copy, 0, skb); 2439e89e9cf5SAnanda Raju if (ret < 0) 2440e89e9cf5SAnanda Raju return -EFAULT; 2441e89e9cf5SAnanda Raju 2442e89e9cf5SAnanda Raju /* copy was successful so update the size parameters */ 2443e89e9cf5SAnanda Raju sk->sk_sndmsg_off += copy; 2444e89e9cf5SAnanda Raju frag->size += copy; 2445e89e9cf5SAnanda Raju skb->len += copy; 2446e89e9cf5SAnanda Raju skb->data_len += copy; 2447e89e9cf5SAnanda Raju offset += copy; 2448e89e9cf5SAnanda Raju length -= copy; 2449e89e9cf5SAnanda Raju 2450e89e9cf5SAnanda Raju } while (length > 0); 2451e89e9cf5SAnanda Raju 2452e89e9cf5SAnanda Raju return 0; 2453e89e9cf5SAnanda Raju } 2454b4ac530fSDavid S. Miller EXPORT_SYMBOL(skb_append_datato_frags); 2455e89e9cf5SAnanda Raju 2456cbb042f9SHerbert Xu /** 2457cbb042f9SHerbert Xu * skb_pull_rcsum - pull skb and update receive checksum 2458cbb042f9SHerbert Xu * @skb: buffer to update 2459cbb042f9SHerbert Xu * @len: length of data pulled 2460cbb042f9SHerbert Xu * 2461cbb042f9SHerbert Xu * This function performs an skb_pull on the packet and updates 2462fee54fa5SUrs Thuermann * the CHECKSUM_COMPLETE checksum. It should be used on 246384fa7933SPatrick McHardy * receive path processing instead of skb_pull unless you know 246484fa7933SPatrick McHardy * that the checksum difference is zero (e.g., a valid IP header) 246584fa7933SPatrick McHardy * or you are setting ip_summed to CHECKSUM_NONE. 2466cbb042f9SHerbert Xu */ 2467cbb042f9SHerbert Xu unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) 2468cbb042f9SHerbert Xu { 2469cbb042f9SHerbert Xu BUG_ON(len > skb->len); 2470cbb042f9SHerbert Xu skb->len -= len; 2471cbb042f9SHerbert Xu BUG_ON(skb->len < skb->data_len); 2472cbb042f9SHerbert Xu skb_postpull_rcsum(skb, skb->data, len); 2473cbb042f9SHerbert Xu return skb->data += len; 2474cbb042f9SHerbert Xu } 2475cbb042f9SHerbert Xu 2476f94691acSArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(skb_pull_rcsum); 2477f94691acSArnaldo Carvalho de Melo 2478f4c50d99SHerbert Xu /** 2479f4c50d99SHerbert Xu * skb_segment - Perform protocol segmentation on skb. 2480f4c50d99SHerbert Xu * @skb: buffer to segment 2481576a30ebSHerbert Xu * @features: features for the output path (see dev->features) 2482f4c50d99SHerbert Xu * 2483f4c50d99SHerbert Xu * This function performs segmentation on the given skb. It returns 24844c821d75SBen Hutchings * a pointer to the first in a list of new skbs for the segments. 24854c821d75SBen Hutchings * In case of error it returns ERR_PTR(err). 2486f4c50d99SHerbert Xu */ 2487576a30ebSHerbert Xu struct sk_buff *skb_segment(struct sk_buff *skb, int features) 2488f4c50d99SHerbert Xu { 2489f4c50d99SHerbert Xu struct sk_buff *segs = NULL; 2490f4c50d99SHerbert Xu struct sk_buff *tail = NULL; 249189319d38SHerbert Xu struct sk_buff *fskb = skb_shinfo(skb)->frag_list; 2492f4c50d99SHerbert Xu unsigned int mss = skb_shinfo(skb)->gso_size; 249398e399f8SArnaldo Carvalho de Melo unsigned int doffset = skb->data - skb_mac_header(skb); 2494f4c50d99SHerbert Xu unsigned int offset = doffset; 2495f4c50d99SHerbert Xu unsigned int headroom; 2496f4c50d99SHerbert Xu unsigned int len; 2497576a30ebSHerbert Xu int sg = features & NETIF_F_SG; 2498f4c50d99SHerbert Xu int nfrags = skb_shinfo(skb)->nr_frags; 2499f4c50d99SHerbert Xu int err = -ENOMEM; 2500f4c50d99SHerbert Xu int i = 0; 2501f4c50d99SHerbert Xu int pos; 2502f4c50d99SHerbert Xu 2503f4c50d99SHerbert Xu __skb_push(skb, doffset); 2504f4c50d99SHerbert Xu headroom = skb_headroom(skb); 2505f4c50d99SHerbert Xu pos = skb_headlen(skb); 2506f4c50d99SHerbert Xu 2507f4c50d99SHerbert Xu do { 2508f4c50d99SHerbert Xu struct sk_buff *nskb; 2509f4c50d99SHerbert Xu skb_frag_t *frag; 2510c8884eddSHerbert Xu int hsize; 2511f4c50d99SHerbert Xu int size; 2512f4c50d99SHerbert Xu 2513f4c50d99SHerbert Xu len = skb->len - offset; 2514f4c50d99SHerbert Xu if (len > mss) 2515f4c50d99SHerbert Xu len = mss; 2516f4c50d99SHerbert Xu 2517f4c50d99SHerbert Xu hsize = skb_headlen(skb) - offset; 2518f4c50d99SHerbert Xu if (hsize < 0) 2519f4c50d99SHerbert Xu hsize = 0; 2520c8884eddSHerbert Xu if (hsize > len || !sg) 2521c8884eddSHerbert Xu hsize = len; 2522f4c50d99SHerbert Xu 252389319d38SHerbert Xu if (!hsize && i >= nfrags) { 252489319d38SHerbert Xu BUG_ON(fskb->len != len); 252589319d38SHerbert Xu 252689319d38SHerbert Xu pos += len; 252789319d38SHerbert Xu nskb = skb_clone(fskb, GFP_ATOMIC); 252889319d38SHerbert Xu fskb = fskb->next; 252989319d38SHerbert Xu 2530f4c50d99SHerbert Xu if (unlikely(!nskb)) 2531f4c50d99SHerbert Xu goto err; 2532f4c50d99SHerbert Xu 253389319d38SHerbert Xu hsize = skb_end_pointer(nskb) - nskb->head; 253489319d38SHerbert Xu if (skb_cow_head(nskb, doffset + headroom)) { 253589319d38SHerbert Xu kfree_skb(nskb); 253689319d38SHerbert Xu goto err; 253789319d38SHerbert Xu } 253889319d38SHerbert Xu 253989319d38SHerbert Xu nskb->truesize += skb_end_pointer(nskb) - nskb->head - 254089319d38SHerbert Xu hsize; 254189319d38SHerbert Xu skb_release_head_state(nskb); 254289319d38SHerbert Xu __skb_push(nskb, doffset); 254389319d38SHerbert Xu } else { 254489319d38SHerbert Xu nskb = alloc_skb(hsize + doffset + headroom, 254589319d38SHerbert Xu GFP_ATOMIC); 254689319d38SHerbert Xu 254789319d38SHerbert Xu if (unlikely(!nskb)) 254889319d38SHerbert Xu goto err; 254989319d38SHerbert Xu 255089319d38SHerbert Xu skb_reserve(nskb, headroom); 255189319d38SHerbert Xu __skb_put(nskb, doffset); 255289319d38SHerbert Xu } 255389319d38SHerbert Xu 2554f4c50d99SHerbert Xu if (segs) 2555f4c50d99SHerbert Xu tail->next = nskb; 2556f4c50d99SHerbert Xu else 2557f4c50d99SHerbert Xu segs = nskb; 2558f4c50d99SHerbert Xu tail = nskb; 2559f4c50d99SHerbert Xu 25606f85a124SHerbert Xu __copy_skb_header(nskb, skb); 2561f4c50d99SHerbert Xu nskb->mac_len = skb->mac_len; 2562f4c50d99SHerbert Xu 2563459a98edSArnaldo Carvalho de Melo skb_reset_mac_header(nskb); 2564ddc7b8e3SArnaldo Carvalho de Melo skb_set_network_header(nskb, skb->mac_len); 2565b0e380b1SArnaldo Carvalho de Melo nskb->transport_header = (nskb->network_header + 2566b0e380b1SArnaldo Carvalho de Melo skb_network_header_len(skb)); 256789319d38SHerbert Xu skb_copy_from_linear_data(skb, nskb->data, doffset); 256889319d38SHerbert Xu 256989319d38SHerbert Xu if (pos >= offset + len) 257089319d38SHerbert Xu continue; 257189319d38SHerbert Xu 2572f4c50d99SHerbert Xu if (!sg) { 25736f85a124SHerbert Xu nskb->ip_summed = CHECKSUM_NONE; 2574f4c50d99SHerbert Xu nskb->csum = skb_copy_and_csum_bits(skb, offset, 2575f4c50d99SHerbert Xu skb_put(nskb, len), 2576f4c50d99SHerbert Xu len, 0); 2577f4c50d99SHerbert Xu continue; 2578f4c50d99SHerbert Xu } 2579f4c50d99SHerbert Xu 2580f4c50d99SHerbert Xu frag = skb_shinfo(nskb)->frags; 2581f4c50d99SHerbert Xu 2582d626f62bSArnaldo Carvalho de Melo skb_copy_from_linear_data_offset(skb, offset, 2583d626f62bSArnaldo Carvalho de Melo skb_put(nskb, hsize), hsize); 2584f4c50d99SHerbert Xu 258589319d38SHerbert Xu while (pos < offset + len && i < nfrags) { 2586f4c50d99SHerbert Xu *frag = skb_shinfo(skb)->frags[i]; 2587f4c50d99SHerbert Xu get_page(frag->page); 2588f4c50d99SHerbert Xu size = frag->size; 2589f4c50d99SHerbert Xu 2590f4c50d99SHerbert Xu if (pos < offset) { 2591f4c50d99SHerbert Xu frag->page_offset += offset - pos; 2592f4c50d99SHerbert Xu frag->size -= offset - pos; 2593f4c50d99SHerbert Xu } 2594f4c50d99SHerbert Xu 259589319d38SHerbert Xu skb_shinfo(nskb)->nr_frags++; 2596f4c50d99SHerbert Xu 2597f4c50d99SHerbert Xu if (pos + size <= offset + len) { 2598f4c50d99SHerbert Xu i++; 2599f4c50d99SHerbert Xu pos += size; 2600f4c50d99SHerbert Xu } else { 2601f4c50d99SHerbert Xu frag->size -= pos + size - (offset + len); 260289319d38SHerbert Xu goto skip_fraglist; 2603f4c50d99SHerbert Xu } 2604f4c50d99SHerbert Xu 2605f4c50d99SHerbert Xu frag++; 2606f4c50d99SHerbert Xu } 2607f4c50d99SHerbert Xu 260889319d38SHerbert Xu if (pos < offset + len) { 260989319d38SHerbert Xu struct sk_buff *fskb2 = fskb; 261089319d38SHerbert Xu 261189319d38SHerbert Xu BUG_ON(pos + fskb->len != offset + len); 261289319d38SHerbert Xu 261389319d38SHerbert Xu pos += fskb->len; 261489319d38SHerbert Xu fskb = fskb->next; 261589319d38SHerbert Xu 261689319d38SHerbert Xu if (fskb2->next) { 261789319d38SHerbert Xu fskb2 = skb_clone(fskb2, GFP_ATOMIC); 261889319d38SHerbert Xu if (!fskb2) 261989319d38SHerbert Xu goto err; 262089319d38SHerbert Xu } else 262189319d38SHerbert Xu skb_get(fskb2); 262289319d38SHerbert Xu 262389319d38SHerbert Xu BUG_ON(skb_shinfo(nskb)->frag_list); 262489319d38SHerbert Xu skb_shinfo(nskb)->frag_list = fskb2; 262589319d38SHerbert Xu } 262689319d38SHerbert Xu 262789319d38SHerbert Xu skip_fraglist: 2628f4c50d99SHerbert Xu nskb->data_len = len - hsize; 2629f4c50d99SHerbert Xu nskb->len += nskb->data_len; 2630f4c50d99SHerbert Xu nskb->truesize += nskb->data_len; 2631f4c50d99SHerbert Xu } while ((offset += len) < skb->len); 2632f4c50d99SHerbert Xu 2633f4c50d99SHerbert Xu return segs; 2634f4c50d99SHerbert Xu 2635f4c50d99SHerbert Xu err: 2636f4c50d99SHerbert Xu while ((skb = segs)) { 2637f4c50d99SHerbert Xu segs = skb->next; 2638b08d5840SPatrick McHardy kfree_skb(skb); 2639f4c50d99SHerbert Xu } 2640f4c50d99SHerbert Xu return ERR_PTR(err); 2641f4c50d99SHerbert Xu } 2642f4c50d99SHerbert Xu EXPORT_SYMBOL_GPL(skb_segment); 2643f4c50d99SHerbert Xu 264471d93b39SHerbert Xu int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) 264571d93b39SHerbert Xu { 264671d93b39SHerbert Xu struct sk_buff *p = *head; 264771d93b39SHerbert Xu struct sk_buff *nskb; 264871d93b39SHerbert Xu unsigned int headroom; 264986911732SHerbert Xu unsigned int len = skb_gro_len(skb); 265071d93b39SHerbert Xu 265186911732SHerbert Xu if (p->len + len >= 65536) 265271d93b39SHerbert Xu return -E2BIG; 265371d93b39SHerbert Xu 265471d93b39SHerbert Xu if (skb_shinfo(p)->frag_list) 265571d93b39SHerbert Xu goto merge; 265681705ad1SHerbert Xu else if (skb_headlen(skb) <= skb_gro_offset(skb)) { 265781705ad1SHerbert Xu if (skb_shinfo(p)->nr_frags + skb_shinfo(skb)->nr_frags > 265881705ad1SHerbert Xu MAX_SKB_FRAGS) 265981705ad1SHerbert Xu return -E2BIG; 266081705ad1SHerbert Xu 266186911732SHerbert Xu skb_shinfo(skb)->frags[0].page_offset += 266286911732SHerbert Xu skb_gro_offset(skb) - skb_headlen(skb); 266386911732SHerbert Xu skb_shinfo(skb)->frags[0].size -= 266486911732SHerbert Xu skb_gro_offset(skb) - skb_headlen(skb); 266586911732SHerbert Xu 26665d38a079SHerbert Xu memcpy(skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags, 26675d38a079SHerbert Xu skb_shinfo(skb)->frags, 26685d38a079SHerbert Xu skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t)); 26695d38a079SHerbert Xu 26705d38a079SHerbert Xu skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags; 2671f5572068SHerbert Xu skb_shinfo(skb)->nr_frags = 0; 2672f5572068SHerbert Xu 2673f5572068SHerbert Xu skb->truesize -= skb->data_len; 2674f5572068SHerbert Xu skb->len -= skb->data_len; 2675f5572068SHerbert Xu skb->data_len = 0; 2676f5572068SHerbert Xu 26775d38a079SHerbert Xu NAPI_GRO_CB(skb)->free = 1; 26785d38a079SHerbert Xu goto done; 26795d38a079SHerbert Xu } 268071d93b39SHerbert Xu 268171d93b39SHerbert Xu headroom = skb_headroom(p); 268286911732SHerbert Xu nskb = netdev_alloc_skb(p->dev, headroom + skb_gro_offset(p)); 268371d93b39SHerbert Xu if (unlikely(!nskb)) 268471d93b39SHerbert Xu return -ENOMEM; 268571d93b39SHerbert Xu 268671d93b39SHerbert Xu __copy_skb_header(nskb, p); 268771d93b39SHerbert Xu nskb->mac_len = p->mac_len; 268871d93b39SHerbert Xu 268971d93b39SHerbert Xu skb_reserve(nskb, headroom); 269086911732SHerbert Xu __skb_put(nskb, skb_gro_offset(p)); 269171d93b39SHerbert Xu 269286911732SHerbert Xu skb_set_mac_header(nskb, skb_mac_header(p) - p->data); 269371d93b39SHerbert Xu skb_set_network_header(nskb, skb_network_offset(p)); 269471d93b39SHerbert Xu skb_set_transport_header(nskb, skb_transport_offset(p)); 269571d93b39SHerbert Xu 269686911732SHerbert Xu __skb_pull(p, skb_gro_offset(p)); 269786911732SHerbert Xu memcpy(skb_mac_header(nskb), skb_mac_header(p), 269886911732SHerbert Xu p->data - skb_mac_header(p)); 269971d93b39SHerbert Xu 270071d93b39SHerbert Xu *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p); 270171d93b39SHerbert Xu skb_shinfo(nskb)->frag_list = p; 2702b530256dSHerbert Xu skb_shinfo(nskb)->gso_size = skb_shinfo(p)->gso_size; 270371d93b39SHerbert Xu skb_header_release(p); 270471d93b39SHerbert Xu nskb->prev = p; 270571d93b39SHerbert Xu 270671d93b39SHerbert Xu nskb->data_len += p->len; 270771d93b39SHerbert Xu nskb->truesize += p->len; 270871d93b39SHerbert Xu nskb->len += p->len; 270971d93b39SHerbert Xu 271071d93b39SHerbert Xu *head = nskb; 271171d93b39SHerbert Xu nskb->next = p->next; 271271d93b39SHerbert Xu p->next = NULL; 271371d93b39SHerbert Xu 271471d93b39SHerbert Xu p = nskb; 271571d93b39SHerbert Xu 271671d93b39SHerbert Xu merge: 271756035022SHerbert Xu if (skb_gro_offset(skb) > skb_headlen(skb)) { 271856035022SHerbert Xu skb_shinfo(skb)->frags[0].page_offset += 271956035022SHerbert Xu skb_gro_offset(skb) - skb_headlen(skb); 272056035022SHerbert Xu skb_shinfo(skb)->frags[0].size -= 272156035022SHerbert Xu skb_gro_offset(skb) - skb_headlen(skb); 272256035022SHerbert Xu skb_gro_reset_offset(skb); 272356035022SHerbert Xu skb_gro_pull(skb, skb_headlen(skb)); 272456035022SHerbert Xu } 272556035022SHerbert Xu 272656035022SHerbert Xu __skb_pull(skb, skb_gro_offset(skb)); 272756035022SHerbert Xu 272871d93b39SHerbert Xu p->prev->next = skb; 272971d93b39SHerbert Xu p->prev = skb; 273071d93b39SHerbert Xu skb_header_release(skb); 273171d93b39SHerbert Xu 27325d38a079SHerbert Xu done: 27335d38a079SHerbert Xu NAPI_GRO_CB(p)->count++; 273437fe4732SHerbert Xu p->data_len += len; 273537fe4732SHerbert Xu p->truesize += len; 273637fe4732SHerbert Xu p->len += len; 273771d93b39SHerbert Xu 273871d93b39SHerbert Xu NAPI_GRO_CB(skb)->same_flow = 1; 273971d93b39SHerbert Xu return 0; 274071d93b39SHerbert Xu } 274171d93b39SHerbert Xu EXPORT_SYMBOL_GPL(skb_gro_receive); 274271d93b39SHerbert Xu 27431da177e4SLinus Torvalds void __init skb_init(void) 27441da177e4SLinus Torvalds { 27451da177e4SLinus Torvalds skbuff_head_cache = kmem_cache_create("skbuff_head_cache", 27461da177e4SLinus Torvalds sizeof(struct sk_buff), 27471da177e4SLinus Torvalds 0, 2748e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 274920c2df83SPaul Mundt NULL); 2750d179cd12SDavid S. Miller skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", 2751d179cd12SDavid S. Miller (2*sizeof(struct sk_buff)) + 2752d179cd12SDavid S. Miller sizeof(atomic_t), 2753d179cd12SDavid S. Miller 0, 2754e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 275520c2df83SPaul Mundt NULL); 27561da177e4SLinus Torvalds } 27571da177e4SLinus Torvalds 2758716ea3a7SDavid Howells /** 2759716ea3a7SDavid Howells * skb_to_sgvec - Fill a scatter-gather list from a socket buffer 2760716ea3a7SDavid Howells * @skb: Socket buffer containing the buffers to be mapped 2761716ea3a7SDavid Howells * @sg: The scatter-gather list to map into 2762716ea3a7SDavid Howells * @offset: The offset into the buffer's contents to start mapping 2763716ea3a7SDavid Howells * @len: Length of buffer space to be mapped 2764716ea3a7SDavid Howells * 2765716ea3a7SDavid Howells * Fill the specified scatter-gather list with mappings/pointers into a 2766716ea3a7SDavid Howells * region of the buffer space attached to a socket buffer. 2767716ea3a7SDavid Howells */ 276851c739d1SDavid S. Miller static int 276951c739d1SDavid S. Miller __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) 2770716ea3a7SDavid Howells { 27711a028e50SDavid S. Miller int start = skb_headlen(skb); 27721a028e50SDavid S. Miller int i, copy = start - offset; 2773716ea3a7SDavid Howells int elt = 0; 2774716ea3a7SDavid Howells 2775716ea3a7SDavid Howells if (copy > 0) { 2776716ea3a7SDavid Howells if (copy > len) 2777716ea3a7SDavid Howells copy = len; 2778642f1490SJens Axboe sg_set_buf(sg, skb->data + offset, copy); 2779716ea3a7SDavid Howells elt++; 2780716ea3a7SDavid Howells if ((len -= copy) == 0) 2781716ea3a7SDavid Howells return elt; 2782716ea3a7SDavid Howells offset += copy; 2783716ea3a7SDavid Howells } 2784716ea3a7SDavid Howells 2785716ea3a7SDavid Howells for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 27861a028e50SDavid S. Miller int end; 2787716ea3a7SDavid Howells 2788547b792cSIlpo Järvinen WARN_ON(start > offset + len); 27891a028e50SDavid S. Miller 27901a028e50SDavid S. Miller end = start + skb_shinfo(skb)->frags[i].size; 2791716ea3a7SDavid Howells if ((copy = end - offset) > 0) { 2792716ea3a7SDavid Howells skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 2793716ea3a7SDavid Howells 2794716ea3a7SDavid Howells if (copy > len) 2795716ea3a7SDavid Howells copy = len; 2796642f1490SJens Axboe sg_set_page(&sg[elt], frag->page, copy, 2797642f1490SJens Axboe frag->page_offset+offset-start); 2798716ea3a7SDavid Howells elt++; 2799716ea3a7SDavid Howells if (!(len -= copy)) 2800716ea3a7SDavid Howells return elt; 2801716ea3a7SDavid Howells offset += copy; 2802716ea3a7SDavid Howells } 28031a028e50SDavid S. Miller start = end; 2804716ea3a7SDavid Howells } 2805716ea3a7SDavid Howells 2806716ea3a7SDavid Howells if (skb_shinfo(skb)->frag_list) { 2807716ea3a7SDavid Howells struct sk_buff *list = skb_shinfo(skb)->frag_list; 2808716ea3a7SDavid Howells 2809716ea3a7SDavid Howells for (; list; list = list->next) { 28101a028e50SDavid S. Miller int end; 2811716ea3a7SDavid Howells 2812547b792cSIlpo Järvinen WARN_ON(start > offset + len); 28131a028e50SDavid S. Miller 28141a028e50SDavid S. Miller end = start + list->len; 2815716ea3a7SDavid Howells if ((copy = end - offset) > 0) { 2816716ea3a7SDavid Howells if (copy > len) 2817716ea3a7SDavid Howells copy = len; 281851c739d1SDavid S. Miller elt += __skb_to_sgvec(list, sg+elt, offset - start, 281951c739d1SDavid S. Miller copy); 2820716ea3a7SDavid Howells if ((len -= copy) == 0) 2821716ea3a7SDavid Howells return elt; 2822716ea3a7SDavid Howells offset += copy; 2823716ea3a7SDavid Howells } 28241a028e50SDavid S. Miller start = end; 2825716ea3a7SDavid Howells } 2826716ea3a7SDavid Howells } 2827716ea3a7SDavid Howells BUG_ON(len); 2828716ea3a7SDavid Howells return elt; 2829716ea3a7SDavid Howells } 2830716ea3a7SDavid Howells 283151c739d1SDavid S. Miller int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) 283251c739d1SDavid S. Miller { 283351c739d1SDavid S. Miller int nsg = __skb_to_sgvec(skb, sg, offset, len); 283451c739d1SDavid S. Miller 2835c46f2334SJens Axboe sg_mark_end(&sg[nsg - 1]); 283651c739d1SDavid S. Miller 283751c739d1SDavid S. Miller return nsg; 283851c739d1SDavid S. Miller } 2839b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_to_sgvec); 284051c739d1SDavid S. Miller 2841716ea3a7SDavid Howells /** 2842716ea3a7SDavid Howells * skb_cow_data - Check that a socket buffer's data buffers are writable 2843716ea3a7SDavid Howells * @skb: The socket buffer to check. 2844716ea3a7SDavid Howells * @tailbits: Amount of trailing space to be added 2845716ea3a7SDavid Howells * @trailer: Returned pointer to the skb where the @tailbits space begins 2846716ea3a7SDavid Howells * 2847716ea3a7SDavid Howells * Make sure that the data buffers attached to a socket buffer are 2848716ea3a7SDavid Howells * writable. If they are not, private copies are made of the data buffers 2849716ea3a7SDavid Howells * and the socket buffer is set to use these instead. 2850716ea3a7SDavid Howells * 2851716ea3a7SDavid Howells * If @tailbits is given, make sure that there is space to write @tailbits 2852716ea3a7SDavid Howells * bytes of data beyond current end of socket buffer. @trailer will be 2853716ea3a7SDavid Howells * set to point to the skb in which this space begins. 2854716ea3a7SDavid Howells * 2855716ea3a7SDavid Howells * The number of scatterlist elements required to completely map the 2856716ea3a7SDavid Howells * COW'd and extended socket buffer will be returned. 2857716ea3a7SDavid Howells */ 2858716ea3a7SDavid Howells int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) 2859716ea3a7SDavid Howells { 2860716ea3a7SDavid Howells int copyflag; 2861716ea3a7SDavid Howells int elt; 2862716ea3a7SDavid Howells struct sk_buff *skb1, **skb_p; 2863716ea3a7SDavid Howells 2864716ea3a7SDavid Howells /* If skb is cloned or its head is paged, reallocate 2865716ea3a7SDavid Howells * head pulling out all the pages (pages are considered not writable 2866716ea3a7SDavid Howells * at the moment even if they are anonymous). 2867716ea3a7SDavid Howells */ 2868716ea3a7SDavid Howells if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) && 2869716ea3a7SDavid Howells __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL) 2870716ea3a7SDavid Howells return -ENOMEM; 2871716ea3a7SDavid Howells 2872716ea3a7SDavid Howells /* Easy case. Most of packets will go this way. */ 2873716ea3a7SDavid Howells if (!skb_shinfo(skb)->frag_list) { 2874716ea3a7SDavid Howells /* A little of trouble, not enough of space for trailer. 2875716ea3a7SDavid Howells * This should not happen, when stack is tuned to generate 2876716ea3a7SDavid Howells * good frames. OK, on miss we reallocate and reserve even more 2877716ea3a7SDavid Howells * space, 128 bytes is fair. */ 2878716ea3a7SDavid Howells 2879716ea3a7SDavid Howells if (skb_tailroom(skb) < tailbits && 2880716ea3a7SDavid Howells pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC)) 2881716ea3a7SDavid Howells return -ENOMEM; 2882716ea3a7SDavid Howells 2883716ea3a7SDavid Howells /* Voila! */ 2884716ea3a7SDavid Howells *trailer = skb; 2885716ea3a7SDavid Howells return 1; 2886716ea3a7SDavid Howells } 2887716ea3a7SDavid Howells 2888716ea3a7SDavid Howells /* Misery. We are in troubles, going to mincer fragments... */ 2889716ea3a7SDavid Howells 2890716ea3a7SDavid Howells elt = 1; 2891716ea3a7SDavid Howells skb_p = &skb_shinfo(skb)->frag_list; 2892716ea3a7SDavid Howells copyflag = 0; 2893716ea3a7SDavid Howells 2894716ea3a7SDavid Howells while ((skb1 = *skb_p) != NULL) { 2895716ea3a7SDavid Howells int ntail = 0; 2896716ea3a7SDavid Howells 2897716ea3a7SDavid Howells /* The fragment is partially pulled by someone, 2898716ea3a7SDavid Howells * this can happen on input. Copy it and everything 2899716ea3a7SDavid Howells * after it. */ 2900716ea3a7SDavid Howells 2901716ea3a7SDavid Howells if (skb_shared(skb1)) 2902716ea3a7SDavid Howells copyflag = 1; 2903716ea3a7SDavid Howells 2904716ea3a7SDavid Howells /* If the skb is the last, worry about trailer. */ 2905716ea3a7SDavid Howells 2906716ea3a7SDavid Howells if (skb1->next == NULL && tailbits) { 2907716ea3a7SDavid Howells if (skb_shinfo(skb1)->nr_frags || 2908716ea3a7SDavid Howells skb_shinfo(skb1)->frag_list || 2909716ea3a7SDavid Howells skb_tailroom(skb1) < tailbits) 2910716ea3a7SDavid Howells ntail = tailbits + 128; 2911716ea3a7SDavid Howells } 2912716ea3a7SDavid Howells 2913716ea3a7SDavid Howells if (copyflag || 2914716ea3a7SDavid Howells skb_cloned(skb1) || 2915716ea3a7SDavid Howells ntail || 2916716ea3a7SDavid Howells skb_shinfo(skb1)->nr_frags || 2917716ea3a7SDavid Howells skb_shinfo(skb1)->frag_list) { 2918716ea3a7SDavid Howells struct sk_buff *skb2; 2919716ea3a7SDavid Howells 2920716ea3a7SDavid Howells /* Fuck, we are miserable poor guys... */ 2921716ea3a7SDavid Howells if (ntail == 0) 2922716ea3a7SDavid Howells skb2 = skb_copy(skb1, GFP_ATOMIC); 2923716ea3a7SDavid Howells else 2924716ea3a7SDavid Howells skb2 = skb_copy_expand(skb1, 2925716ea3a7SDavid Howells skb_headroom(skb1), 2926716ea3a7SDavid Howells ntail, 2927716ea3a7SDavid Howells GFP_ATOMIC); 2928716ea3a7SDavid Howells if (unlikely(skb2 == NULL)) 2929716ea3a7SDavid Howells return -ENOMEM; 2930716ea3a7SDavid Howells 2931716ea3a7SDavid Howells if (skb1->sk) 2932716ea3a7SDavid Howells skb_set_owner_w(skb2, skb1->sk); 2933716ea3a7SDavid Howells 2934716ea3a7SDavid Howells /* Looking around. Are we still alive? 2935716ea3a7SDavid Howells * OK, link new skb, drop old one */ 2936716ea3a7SDavid Howells 2937716ea3a7SDavid Howells skb2->next = skb1->next; 2938716ea3a7SDavid Howells *skb_p = skb2; 2939716ea3a7SDavid Howells kfree_skb(skb1); 2940716ea3a7SDavid Howells skb1 = skb2; 2941716ea3a7SDavid Howells } 2942716ea3a7SDavid Howells elt++; 2943716ea3a7SDavid Howells *trailer = skb1; 2944716ea3a7SDavid Howells skb_p = &skb1->next; 2945716ea3a7SDavid Howells } 2946716ea3a7SDavid Howells 2947716ea3a7SDavid Howells return elt; 2948716ea3a7SDavid Howells } 2949b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_cow_data); 2950716ea3a7SDavid Howells 2951ac45f602SPatrick Ohly void skb_tstamp_tx(struct sk_buff *orig_skb, 2952ac45f602SPatrick Ohly struct skb_shared_hwtstamps *hwtstamps) 2953ac45f602SPatrick Ohly { 2954ac45f602SPatrick Ohly struct sock *sk = orig_skb->sk; 2955ac45f602SPatrick Ohly struct sock_exterr_skb *serr; 2956ac45f602SPatrick Ohly struct sk_buff *skb; 2957ac45f602SPatrick Ohly int err; 2958ac45f602SPatrick Ohly 2959ac45f602SPatrick Ohly if (!sk) 2960ac45f602SPatrick Ohly return; 2961ac45f602SPatrick Ohly 2962ac45f602SPatrick Ohly skb = skb_clone(orig_skb, GFP_ATOMIC); 2963ac45f602SPatrick Ohly if (!skb) 2964ac45f602SPatrick Ohly return; 2965ac45f602SPatrick Ohly 2966ac45f602SPatrick Ohly if (hwtstamps) { 2967ac45f602SPatrick Ohly *skb_hwtstamps(skb) = 2968ac45f602SPatrick Ohly *hwtstamps; 2969ac45f602SPatrick Ohly } else { 2970ac45f602SPatrick Ohly /* 2971ac45f602SPatrick Ohly * no hardware time stamps available, 2972ac45f602SPatrick Ohly * so keep the skb_shared_tx and only 2973ac45f602SPatrick Ohly * store software time stamp 2974ac45f602SPatrick Ohly */ 2975ac45f602SPatrick Ohly skb->tstamp = ktime_get_real(); 2976ac45f602SPatrick Ohly } 2977ac45f602SPatrick Ohly 2978ac45f602SPatrick Ohly serr = SKB_EXT_ERR(skb); 2979ac45f602SPatrick Ohly memset(serr, 0, sizeof(*serr)); 2980ac45f602SPatrick Ohly serr->ee.ee_errno = ENOMSG; 2981ac45f602SPatrick Ohly serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; 2982ac45f602SPatrick Ohly err = sock_queue_err_skb(sk, skb); 2983ac45f602SPatrick Ohly if (err) 2984ac45f602SPatrick Ohly kfree_skb(skb); 2985ac45f602SPatrick Ohly } 2986ac45f602SPatrick Ohly EXPORT_SYMBOL_GPL(skb_tstamp_tx); 2987ac45f602SPatrick Ohly 2988ac45f602SPatrick Ohly 2989f35d9d8aSRusty Russell /** 2990f35d9d8aSRusty Russell * skb_partial_csum_set - set up and verify partial csum values for packet 2991f35d9d8aSRusty Russell * @skb: the skb to set 2992f35d9d8aSRusty Russell * @start: the number of bytes after skb->data to start checksumming. 2993f35d9d8aSRusty Russell * @off: the offset from start to place the checksum. 2994f35d9d8aSRusty Russell * 2995f35d9d8aSRusty Russell * For untrusted partially-checksummed packets, we need to make sure the values 2996f35d9d8aSRusty Russell * for skb->csum_start and skb->csum_offset are valid so we don't oops. 2997f35d9d8aSRusty Russell * 2998f35d9d8aSRusty Russell * This function checks and sets those values and skb->ip_summed: if this 2999f35d9d8aSRusty Russell * returns false you should drop the packet. 3000f35d9d8aSRusty Russell */ 3001f35d9d8aSRusty Russell bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off) 3002f35d9d8aSRusty Russell { 3003f35d9d8aSRusty Russell if (unlikely(start > skb->len - 2) || 3004f35d9d8aSRusty Russell unlikely((int)start + off > skb->len - 2)) { 3005f35d9d8aSRusty Russell if (net_ratelimit()) 3006f35d9d8aSRusty Russell printk(KERN_WARNING 3007f35d9d8aSRusty Russell "bad partial csum: csum=%u/%u len=%u\n", 3008f35d9d8aSRusty Russell start, off, skb->len); 3009f35d9d8aSRusty Russell return false; 3010f35d9d8aSRusty Russell } 3011f35d9d8aSRusty Russell skb->ip_summed = CHECKSUM_PARTIAL; 3012f35d9d8aSRusty Russell skb->csum_start = skb_headroom(skb) + start; 3013f35d9d8aSRusty Russell skb->csum_offset = off; 3014f35d9d8aSRusty Russell return true; 3015f35d9d8aSRusty Russell } 3016b4ac530fSDavid S. Miller EXPORT_SYMBOL_GPL(skb_partial_csum_set); 3017f35d9d8aSRusty Russell 30184497b076SBen Hutchings void __skb_warn_lro_forwarding(const struct sk_buff *skb) 30194497b076SBen Hutchings { 30204497b076SBen Hutchings if (net_ratelimit()) 30214497b076SBen Hutchings pr_warning("%s: received packets cannot be forwarded" 30224497b076SBen Hutchings " while LRO is enabled\n", skb->dev->name); 30234497b076SBen Hutchings } 30244497b076SBen Hutchings EXPORT_SYMBOL(__skb_warn_lro_forwarding); 3025