11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * Routines having to do with the 'struct sk_buff' memory handlers. 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Authors: Alan Cox <iiitac@pyr.swan.ac.uk> 51da177e4SLinus Torvalds * Florian La Roche <rzsfl@rz.uni-sb.de> 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * Version: $Id: skbuff.c,v 1.90 2001/11/07 05:56:19 davem Exp $ 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * Fixes: 101da177e4SLinus Torvalds * Alan Cox : Fixed the worst of the load 111da177e4SLinus Torvalds * balancer bugs. 121da177e4SLinus Torvalds * Dave Platt : Interrupt stacking fix. 131da177e4SLinus Torvalds * Richard Kooijman : Timestamp fixes. 141da177e4SLinus Torvalds * Alan Cox : Changed buffer format. 151da177e4SLinus Torvalds * Alan Cox : destructor hook for AF_UNIX etc. 161da177e4SLinus Torvalds * Linus Torvalds : Better skb_clone. 171da177e4SLinus Torvalds * Alan Cox : Added skb_copy. 181da177e4SLinus Torvalds * Alan Cox : Added all the changed routines Linus 191da177e4SLinus Torvalds * only put in the headers 201da177e4SLinus Torvalds * Ray VanTassle : Fixed --skb->lock in free 211da177e4SLinus Torvalds * Alan Cox : skb_copy copy arp field 221da177e4SLinus Torvalds * Andi Kleen : slabified it. 231da177e4SLinus Torvalds * Robert Olsson : Removed skb_head_pool 241da177e4SLinus Torvalds * 251da177e4SLinus Torvalds * NOTE: 261da177e4SLinus Torvalds * The __skb_ routines should be called with interrupts 271da177e4SLinus Torvalds * disabled, or you better be *real* sure that the operation is atomic 281da177e4SLinus Torvalds * with respect to whatever list is being frobbed (e.g. via lock_sock() 291da177e4SLinus Torvalds * or via disabling bottom half handlers, etc). 301da177e4SLinus Torvalds * 311da177e4SLinus Torvalds * This program is free software; you can redistribute it and/or 321da177e4SLinus Torvalds * modify it under the terms of the GNU General Public License 331da177e4SLinus Torvalds * as published by the Free Software Foundation; either version 341da177e4SLinus Torvalds * 2 of the License, or (at your option) any later version. 351da177e4SLinus Torvalds */ 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds /* 381da177e4SLinus Torvalds * The functions in this file will not compile correctly with gcc 2.4.x 391da177e4SLinus Torvalds */ 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds #include <linux/module.h> 421da177e4SLinus Torvalds #include <linux/types.h> 431da177e4SLinus Torvalds #include <linux/kernel.h> 441da177e4SLinus Torvalds #include <linux/sched.h> 451da177e4SLinus Torvalds #include <linux/mm.h> 461da177e4SLinus Torvalds #include <linux/interrupt.h> 471da177e4SLinus Torvalds #include <linux/in.h> 481da177e4SLinus Torvalds #include <linux/inet.h> 491da177e4SLinus Torvalds #include <linux/slab.h> 501da177e4SLinus Torvalds #include <linux/netdevice.h> 511da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 521da177e4SLinus Torvalds #include <net/pkt_sched.h> 531da177e4SLinus Torvalds #endif 541da177e4SLinus Torvalds #include <linux/string.h> 551da177e4SLinus Torvalds #include <linux/skbuff.h> 561da177e4SLinus Torvalds #include <linux/cache.h> 571da177e4SLinus Torvalds #include <linux/rtnetlink.h> 581da177e4SLinus Torvalds #include <linux/init.h> 591da177e4SLinus Torvalds #include <linux/highmem.h> 601da177e4SLinus Torvalds 611da177e4SLinus Torvalds #include <net/protocol.h> 621da177e4SLinus Torvalds #include <net/dst.h> 631da177e4SLinus Torvalds #include <net/sock.h> 641da177e4SLinus Torvalds #include <net/checksum.h> 651da177e4SLinus Torvalds #include <net/xfrm.h> 661da177e4SLinus Torvalds 671da177e4SLinus Torvalds #include <asm/uaccess.h> 681da177e4SLinus Torvalds #include <asm/system.h> 691da177e4SLinus Torvalds 70ba89966cSEric Dumazet static kmem_cache_t *skbuff_head_cache __read_mostly; 71ba89966cSEric Dumazet static kmem_cache_t *skbuff_fclone_cache __read_mostly; 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds /* 741da177e4SLinus Torvalds * Keep out-of-line to prevent kernel bloat. 751da177e4SLinus Torvalds * __builtin_return_address is not used because it is not always 761da177e4SLinus Torvalds * reliable. 771da177e4SLinus Torvalds */ 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds /** 801da177e4SLinus Torvalds * skb_over_panic - private function 811da177e4SLinus Torvalds * @skb: buffer 821da177e4SLinus Torvalds * @sz: size 831da177e4SLinus Torvalds * @here: address 841da177e4SLinus Torvalds * 851da177e4SLinus Torvalds * Out of line support code for skb_put(). Not user callable. 861da177e4SLinus Torvalds */ 871da177e4SLinus Torvalds void skb_over_panic(struct sk_buff *skb, int sz, void *here) 881da177e4SLinus Torvalds { 8926095455SPatrick McHardy printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " 9026095455SPatrick McHardy "data:%p tail:%p end:%p dev:%s\n", 9126095455SPatrick McHardy here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, 9226095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 931da177e4SLinus Torvalds BUG(); 941da177e4SLinus Torvalds } 951da177e4SLinus Torvalds 961da177e4SLinus Torvalds /** 971da177e4SLinus Torvalds * skb_under_panic - private function 981da177e4SLinus Torvalds * @skb: buffer 991da177e4SLinus Torvalds * @sz: size 1001da177e4SLinus Torvalds * @here: address 1011da177e4SLinus Torvalds * 1021da177e4SLinus Torvalds * Out of line support code for skb_push(). Not user callable. 1031da177e4SLinus Torvalds */ 1041da177e4SLinus Torvalds 1051da177e4SLinus Torvalds void skb_under_panic(struct sk_buff *skb, int sz, void *here) 1061da177e4SLinus Torvalds { 10726095455SPatrick McHardy printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " 10826095455SPatrick McHardy "data:%p tail:%p end:%p dev:%s\n", 10926095455SPatrick McHardy here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, 11026095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1111da177e4SLinus Torvalds BUG(); 1121da177e4SLinus Torvalds } 1131da177e4SLinus Torvalds 114dc6de336SDavid S. Miller void skb_truesize_bug(struct sk_buff *skb) 115dc6de336SDavid S. Miller { 116dc6de336SDavid S. Miller printk(KERN_ERR "SKB BUG: Invalid truesize (%u) " 117dc6de336SDavid S. Miller "len=%u, sizeof(sk_buff)=%Zd\n", 118dc6de336SDavid S. Miller skb->truesize, skb->len, sizeof(struct sk_buff)); 119dc6de336SDavid S. Miller } 120dc6de336SDavid S. Miller EXPORT_SYMBOL(skb_truesize_bug); 121dc6de336SDavid S. Miller 1221da177e4SLinus Torvalds /* Allocate a new skbuff. We do this ourselves so we can fill in a few 1231da177e4SLinus Torvalds * 'private' fields and also do memory statistics to find all the 1241da177e4SLinus Torvalds * [BEEP] leaks. 1251da177e4SLinus Torvalds * 1261da177e4SLinus Torvalds */ 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds /** 129d179cd12SDavid S. Miller * __alloc_skb - allocate a network buffer 1301da177e4SLinus Torvalds * @size: size to allocate 1311da177e4SLinus Torvalds * @gfp_mask: allocation mask 132c83c2486SRandy Dunlap * @fclone: allocate from fclone cache instead of head cache 133c83c2486SRandy Dunlap * and allocate a cloned (child) skb 1341da177e4SLinus Torvalds * 1351da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and a 1361da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 1371da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 1381da177e4SLinus Torvalds * 1391da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1401da177e4SLinus Torvalds * %GFP_ATOMIC. 1411da177e4SLinus Torvalds */ 142dd0fc66fSAl Viro struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, 143d179cd12SDavid S. Miller int fclone) 1441da177e4SLinus Torvalds { 1458798b3fbSHerbert Xu kmem_cache_t *cache; 1464947d3efSBenjamin LaHaise struct skb_shared_info *shinfo; 1471da177e4SLinus Torvalds struct sk_buff *skb; 1481da177e4SLinus Torvalds u8 *data; 1491da177e4SLinus Torvalds 1508798b3fbSHerbert Xu cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; 1518798b3fbSHerbert Xu 1521da177e4SLinus Torvalds /* Get the HEAD */ 1538798b3fbSHerbert Xu skb = kmem_cache_alloc(cache, gfp_mask & ~__GFP_DMA); 1541da177e4SLinus Torvalds if (!skb) 1551da177e4SLinus Torvalds goto out; 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds /* Get the DATA. Size must match skb_add_mtu(). */ 1581da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 1591d2c8eeaSChristoph Hellwig data = kmalloc_track_caller(size + sizeof(struct skb_shared_info), 1601d2c8eeaSChristoph Hellwig gfp_mask); 1611da177e4SLinus Torvalds if (!data) 1621da177e4SLinus Torvalds goto nodata; 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds memset(skb, 0, offsetof(struct sk_buff, truesize)); 1651da177e4SLinus Torvalds skb->truesize = size + sizeof(struct sk_buff); 1661da177e4SLinus Torvalds atomic_set(&skb->users, 1); 1671da177e4SLinus Torvalds skb->head = data; 1681da177e4SLinus Torvalds skb->data = data; 1691da177e4SLinus Torvalds skb->tail = data; 1701da177e4SLinus Torvalds skb->end = data + size; 1714947d3efSBenjamin LaHaise /* make sure we initialize shinfo sequentially */ 1724947d3efSBenjamin LaHaise shinfo = skb_shinfo(skb); 1734947d3efSBenjamin LaHaise atomic_set(&shinfo->dataref, 1); 1744947d3efSBenjamin LaHaise shinfo->nr_frags = 0; 1757967168cSHerbert Xu shinfo->gso_size = 0; 1767967168cSHerbert Xu shinfo->gso_segs = 0; 1777967168cSHerbert Xu shinfo->gso_type = 0; 1784947d3efSBenjamin LaHaise shinfo->ip6_frag_id = 0; 1794947d3efSBenjamin LaHaise shinfo->frag_list = NULL; 1804947d3efSBenjamin LaHaise 181d179cd12SDavid S. Miller if (fclone) { 182d179cd12SDavid S. Miller struct sk_buff *child = skb + 1; 183d179cd12SDavid S. Miller atomic_t *fclone_ref = (atomic_t *) (child + 1); 1841da177e4SLinus Torvalds 185d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_ORIG; 186d179cd12SDavid S. Miller atomic_set(fclone_ref, 1); 187d179cd12SDavid S. Miller 188d179cd12SDavid S. Miller child->fclone = SKB_FCLONE_UNAVAILABLE; 189d179cd12SDavid S. Miller } 1901da177e4SLinus Torvalds out: 1911da177e4SLinus Torvalds return skb; 1921da177e4SLinus Torvalds nodata: 1938798b3fbSHerbert Xu kmem_cache_free(cache, skb); 1941da177e4SLinus Torvalds skb = NULL; 1951da177e4SLinus Torvalds goto out; 1961da177e4SLinus Torvalds } 1971da177e4SLinus Torvalds 1981da177e4SLinus Torvalds /** 1991da177e4SLinus Torvalds * alloc_skb_from_cache - allocate a network buffer 2001da177e4SLinus Torvalds * @cp: kmem_cache from which to allocate the data area 2011da177e4SLinus Torvalds * (object size must be big enough for @size bytes + skb overheads) 2021da177e4SLinus Torvalds * @size: size to allocate 2031da177e4SLinus Torvalds * @gfp_mask: allocation mask 2041da177e4SLinus Torvalds * 2051da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and 2061da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 2071da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 2081da177e4SLinus Torvalds * 2091da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 2101da177e4SLinus Torvalds * %GFP_ATOMIC. 2111da177e4SLinus Torvalds */ 2121da177e4SLinus Torvalds struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp, 21386a76cafSVictor Fusco unsigned int size, 214dd0fc66fSAl Viro gfp_t gfp_mask) 2151da177e4SLinus Torvalds { 2161da177e4SLinus Torvalds struct sk_buff *skb; 2171da177e4SLinus Torvalds u8 *data; 2181da177e4SLinus Torvalds 2191da177e4SLinus Torvalds /* Get the HEAD */ 2201da177e4SLinus Torvalds skb = kmem_cache_alloc(skbuff_head_cache, 2211da177e4SLinus Torvalds gfp_mask & ~__GFP_DMA); 2221da177e4SLinus Torvalds if (!skb) 2231da177e4SLinus Torvalds goto out; 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvalds /* Get the DATA. */ 2261da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 2271da177e4SLinus Torvalds data = kmem_cache_alloc(cp, gfp_mask); 2281da177e4SLinus Torvalds if (!data) 2291da177e4SLinus Torvalds goto nodata; 2301da177e4SLinus Torvalds 2311da177e4SLinus Torvalds memset(skb, 0, offsetof(struct sk_buff, truesize)); 2321da177e4SLinus Torvalds skb->truesize = size + sizeof(struct sk_buff); 2331da177e4SLinus Torvalds atomic_set(&skb->users, 1); 2341da177e4SLinus Torvalds skb->head = data; 2351da177e4SLinus Torvalds skb->data = data; 2361da177e4SLinus Torvalds skb->tail = data; 2371da177e4SLinus Torvalds skb->end = data + size; 2381da177e4SLinus Torvalds 2391da177e4SLinus Torvalds atomic_set(&(skb_shinfo(skb)->dataref), 1); 2401da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 2417967168cSHerbert Xu skb_shinfo(skb)->gso_size = 0; 2427967168cSHerbert Xu skb_shinfo(skb)->gso_segs = 0; 2437967168cSHerbert Xu skb_shinfo(skb)->gso_type = 0; 2441da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = NULL; 2451da177e4SLinus Torvalds out: 2461da177e4SLinus Torvalds return skb; 2471da177e4SLinus Torvalds nodata: 2481da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 2491da177e4SLinus Torvalds skb = NULL; 2501da177e4SLinus Torvalds goto out; 2511da177e4SLinus Torvalds } 2521da177e4SLinus Torvalds 2538af27456SChristoph Hellwig /** 2548af27456SChristoph Hellwig * __netdev_alloc_skb - allocate an skbuff for rx on a specific device 2558af27456SChristoph Hellwig * @dev: network device to receive on 2568af27456SChristoph Hellwig * @length: length to allocate 2578af27456SChristoph Hellwig * @gfp_mask: get_free_pages mask, passed to alloc_skb 2588af27456SChristoph Hellwig * 2598af27456SChristoph Hellwig * Allocate a new &sk_buff and assign it a usage count of one. The 2608af27456SChristoph Hellwig * buffer has unspecified headroom built in. Users should allocate 2618af27456SChristoph Hellwig * the headroom they think they need without accounting for the 2628af27456SChristoph Hellwig * built in space. The built in space is used for optimisations. 2638af27456SChristoph Hellwig * 2648af27456SChristoph Hellwig * %NULL is returned if there is no free memory. 2658af27456SChristoph Hellwig */ 2668af27456SChristoph Hellwig struct sk_buff *__netdev_alloc_skb(struct net_device *dev, 2678af27456SChristoph Hellwig unsigned int length, gfp_t gfp_mask) 2688af27456SChristoph Hellwig { 2698af27456SChristoph Hellwig struct sk_buff *skb; 2708af27456SChristoph Hellwig 2718af27456SChristoph Hellwig skb = alloc_skb(length + NET_SKB_PAD, gfp_mask); 2727b2e497aSChristoph Hellwig if (likely(skb)) { 2738af27456SChristoph Hellwig skb_reserve(skb, NET_SKB_PAD); 2747b2e497aSChristoph Hellwig skb->dev = dev; 2757b2e497aSChristoph Hellwig } 2768af27456SChristoph Hellwig return skb; 2778af27456SChristoph Hellwig } 2781da177e4SLinus Torvalds 27927b437c8SHerbert Xu static void skb_drop_list(struct sk_buff **listp) 2801da177e4SLinus Torvalds { 28127b437c8SHerbert Xu struct sk_buff *list = *listp; 2821da177e4SLinus Torvalds 28327b437c8SHerbert Xu *listp = NULL; 2841da177e4SLinus Torvalds 2851da177e4SLinus Torvalds do { 2861da177e4SLinus Torvalds struct sk_buff *this = list; 2871da177e4SLinus Torvalds list = list->next; 2881da177e4SLinus Torvalds kfree_skb(this); 2891da177e4SLinus Torvalds } while (list); 2901da177e4SLinus Torvalds } 2911da177e4SLinus Torvalds 29227b437c8SHerbert Xu static inline void skb_drop_fraglist(struct sk_buff *skb) 29327b437c8SHerbert Xu { 29427b437c8SHerbert Xu skb_drop_list(&skb_shinfo(skb)->frag_list); 29527b437c8SHerbert Xu } 29627b437c8SHerbert Xu 2971da177e4SLinus Torvalds static void skb_clone_fraglist(struct sk_buff *skb) 2981da177e4SLinus Torvalds { 2991da177e4SLinus Torvalds struct sk_buff *list; 3001da177e4SLinus Torvalds 3011da177e4SLinus Torvalds for (list = skb_shinfo(skb)->frag_list; list; list = list->next) 3021da177e4SLinus Torvalds skb_get(list); 3031da177e4SLinus Torvalds } 3041da177e4SLinus Torvalds 3055bba1712SAdrian Bunk static void skb_release_data(struct sk_buff *skb) 3061da177e4SLinus Torvalds { 3071da177e4SLinus Torvalds if (!skb->cloned || 3081da177e4SLinus Torvalds !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, 3091da177e4SLinus Torvalds &skb_shinfo(skb)->dataref)) { 3101da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 3111da177e4SLinus Torvalds int i; 3121da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 3131da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 3141da177e4SLinus Torvalds } 3151da177e4SLinus Torvalds 3161da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 3171da177e4SLinus Torvalds skb_drop_fraglist(skb); 3181da177e4SLinus Torvalds 3191da177e4SLinus Torvalds kfree(skb->head); 3201da177e4SLinus Torvalds } 3211da177e4SLinus Torvalds } 3221da177e4SLinus Torvalds 3231da177e4SLinus Torvalds /* 3241da177e4SLinus Torvalds * Free an skbuff by memory without cleaning the state. 3251da177e4SLinus Torvalds */ 3261da177e4SLinus Torvalds void kfree_skbmem(struct sk_buff *skb) 3271da177e4SLinus Torvalds { 328d179cd12SDavid S. Miller struct sk_buff *other; 329d179cd12SDavid S. Miller atomic_t *fclone_ref; 330d179cd12SDavid S. Miller 3311da177e4SLinus Torvalds skb_release_data(skb); 332d179cd12SDavid S. Miller switch (skb->fclone) { 333d179cd12SDavid S. Miller case SKB_FCLONE_UNAVAILABLE: 3341da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 335d179cd12SDavid S. Miller break; 336d179cd12SDavid S. Miller 337d179cd12SDavid S. Miller case SKB_FCLONE_ORIG: 338d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 2); 339d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 340d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, skb); 341d179cd12SDavid S. Miller break; 342d179cd12SDavid S. Miller 343d179cd12SDavid S. Miller case SKB_FCLONE_CLONE: 344d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 1); 345d179cd12SDavid S. Miller other = skb - 1; 346d179cd12SDavid S. Miller 347d179cd12SDavid S. Miller /* The clone portion is available for 348d179cd12SDavid S. Miller * fast-cloning again. 349d179cd12SDavid S. Miller */ 350d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_UNAVAILABLE; 351d179cd12SDavid S. Miller 352d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 353d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, other); 354d179cd12SDavid S. Miller break; 355d179cd12SDavid S. Miller }; 3561da177e4SLinus Torvalds } 3571da177e4SLinus Torvalds 3581da177e4SLinus Torvalds /** 3591da177e4SLinus Torvalds * __kfree_skb - private function 3601da177e4SLinus Torvalds * @skb: buffer 3611da177e4SLinus Torvalds * 3621da177e4SLinus Torvalds * Free an sk_buff. Release anything attached to the buffer. 3631da177e4SLinus Torvalds * Clean the state. This is an internal helper function. Users should 3641da177e4SLinus Torvalds * always call kfree_skb 3651da177e4SLinus Torvalds */ 3661da177e4SLinus Torvalds 3671da177e4SLinus Torvalds void __kfree_skb(struct sk_buff *skb) 3681da177e4SLinus Torvalds { 3691da177e4SLinus Torvalds dst_release(skb->dst); 3701da177e4SLinus Torvalds #ifdef CONFIG_XFRM 3711da177e4SLinus Torvalds secpath_put(skb->sp); 3721da177e4SLinus Torvalds #endif 3731da177e4SLinus Torvalds if (skb->destructor) { 3749c2b3328SStephen Hemminger WARN_ON(in_irq()); 3751da177e4SLinus Torvalds skb->destructor(skb); 3761da177e4SLinus Torvalds } 3771da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 3781da177e4SLinus Torvalds nf_conntrack_put(skb->nfct); 3799fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 3809fb9cbb1SYasuyuki Kozakai nf_conntrack_put_reasm(skb->nfct_reasm); 3819fb9cbb1SYasuyuki Kozakai #endif 3821da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 3831da177e4SLinus Torvalds nf_bridge_put(skb->nf_bridge); 3841da177e4SLinus Torvalds #endif 3851da177e4SLinus Torvalds #endif 3861da177e4SLinus Torvalds /* XXX: IS this still necessary? - JHS */ 3871da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 3881da177e4SLinus Torvalds skb->tc_index = 0; 3891da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 3901da177e4SLinus Torvalds skb->tc_verd = 0; 3911da177e4SLinus Torvalds #endif 3921da177e4SLinus Torvalds #endif 3931da177e4SLinus Torvalds 3941da177e4SLinus Torvalds kfree_skbmem(skb); 3951da177e4SLinus Torvalds } 3961da177e4SLinus Torvalds 3971da177e4SLinus Torvalds /** 398231d06aeSJörn Engel * kfree_skb - free an sk_buff 399231d06aeSJörn Engel * @skb: buffer to free 400231d06aeSJörn Engel * 401231d06aeSJörn Engel * Drop a reference to the buffer and free it if the usage count has 402231d06aeSJörn Engel * hit zero. 403231d06aeSJörn Engel */ 404231d06aeSJörn Engel void kfree_skb(struct sk_buff *skb) 405231d06aeSJörn Engel { 406231d06aeSJörn Engel if (unlikely(!skb)) 407231d06aeSJörn Engel return; 408231d06aeSJörn Engel if (likely(atomic_read(&skb->users) == 1)) 409231d06aeSJörn Engel smp_rmb(); 410231d06aeSJörn Engel else if (likely(!atomic_dec_and_test(&skb->users))) 411231d06aeSJörn Engel return; 412231d06aeSJörn Engel __kfree_skb(skb); 413231d06aeSJörn Engel } 414231d06aeSJörn Engel 415231d06aeSJörn Engel /** 4161da177e4SLinus Torvalds * skb_clone - duplicate an sk_buff 4171da177e4SLinus Torvalds * @skb: buffer to clone 4181da177e4SLinus Torvalds * @gfp_mask: allocation priority 4191da177e4SLinus Torvalds * 4201da177e4SLinus Torvalds * Duplicate an &sk_buff. The new one is not owned by a socket. Both 4211da177e4SLinus Torvalds * copies share the same packet data but not structure. The new 4221da177e4SLinus Torvalds * buffer has a reference count of 1. If the allocation fails the 4231da177e4SLinus Torvalds * function returns %NULL otherwise the new buffer is returned. 4241da177e4SLinus Torvalds * 4251da177e4SLinus Torvalds * If this function is called from an interrupt gfp_mask() must be 4261da177e4SLinus Torvalds * %GFP_ATOMIC. 4271da177e4SLinus Torvalds */ 4281da177e4SLinus Torvalds 429dd0fc66fSAl Viro struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) 4301da177e4SLinus Torvalds { 431d179cd12SDavid S. Miller struct sk_buff *n; 4321da177e4SLinus Torvalds 433d179cd12SDavid S. Miller n = skb + 1; 434d179cd12SDavid S. Miller if (skb->fclone == SKB_FCLONE_ORIG && 435d179cd12SDavid S. Miller n->fclone == SKB_FCLONE_UNAVAILABLE) { 436d179cd12SDavid S. Miller atomic_t *fclone_ref = (atomic_t *) (n + 1); 437d179cd12SDavid S. Miller n->fclone = SKB_FCLONE_CLONE; 438d179cd12SDavid S. Miller atomic_inc(fclone_ref); 439d179cd12SDavid S. Miller } else { 440d179cd12SDavid S. Miller n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); 4411da177e4SLinus Torvalds if (!n) 4421da177e4SLinus Torvalds return NULL; 443d179cd12SDavid S. Miller n->fclone = SKB_FCLONE_UNAVAILABLE; 444d179cd12SDavid S. Miller } 4451da177e4SLinus Torvalds 4461da177e4SLinus Torvalds #define C(x) n->x = skb->x 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds n->next = n->prev = NULL; 4491da177e4SLinus Torvalds n->sk = NULL; 450a61bbcf2SPatrick McHardy C(tstamp); 4511da177e4SLinus Torvalds C(dev); 4521da177e4SLinus Torvalds C(h); 4531da177e4SLinus Torvalds C(nh); 4541da177e4SLinus Torvalds C(mac); 4551da177e4SLinus Torvalds C(dst); 4561da177e4SLinus Torvalds dst_clone(skb->dst); 4571da177e4SLinus Torvalds C(sp); 4581da177e4SLinus Torvalds #ifdef CONFIG_INET 4591da177e4SLinus Torvalds secpath_get(skb->sp); 4601da177e4SLinus Torvalds #endif 4611da177e4SLinus Torvalds memcpy(n->cb, skb->cb, sizeof(skb->cb)); 4621da177e4SLinus Torvalds C(len); 4631da177e4SLinus Torvalds C(data_len); 4641da177e4SLinus Torvalds C(csum); 4651da177e4SLinus Torvalds C(local_df); 4661da177e4SLinus Torvalds n->cloned = 1; 4671da177e4SLinus Torvalds n->nohdr = 0; 4681da177e4SLinus Torvalds C(pkt_type); 4691da177e4SLinus Torvalds C(ip_summed); 4701da177e4SLinus Torvalds C(priority); 471a8372f03SYOSHIFUJI Hideaki #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 472a8372f03SYOSHIFUJI Hideaki C(ipvs_property); 473a8372f03SYOSHIFUJI Hideaki #endif 4741da177e4SLinus Torvalds C(protocol); 4751da177e4SLinus Torvalds n->destructor = NULL; 4761da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 4771da177e4SLinus Torvalds C(nfmark); 4781da177e4SLinus Torvalds C(nfct); 4791da177e4SLinus Torvalds nf_conntrack_get(skb->nfct); 4801da177e4SLinus Torvalds C(nfctinfo); 4819fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4829fb9cbb1SYasuyuki Kozakai C(nfct_reasm); 4839fb9cbb1SYasuyuki Kozakai nf_conntrack_get_reasm(skb->nfct_reasm); 4849fb9cbb1SYasuyuki Kozakai #endif 4851da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 4861da177e4SLinus Torvalds C(nf_bridge); 4871da177e4SLinus Torvalds nf_bridge_get(skb->nf_bridge); 4881da177e4SLinus Torvalds #endif 4891da177e4SLinus Torvalds #endif /*CONFIG_NETFILTER*/ 4901da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 4911da177e4SLinus Torvalds C(tc_index); 4921da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 4931da177e4SLinus Torvalds n->tc_verd = SET_TC_VERD(skb->tc_verd,0); 494b72f6eccSDavid S. Miller n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd); 495b72f6eccSDavid S. Miller n->tc_verd = CLR_TC_MUNGED(n->tc_verd); 4961da177e4SLinus Torvalds C(input_dev); 4971da177e4SLinus Torvalds #endif 498984bc16cSJames Morris skb_copy_secmark(n, skb); 4991da177e4SLinus Torvalds #endif 5001da177e4SLinus Torvalds C(truesize); 5011da177e4SLinus Torvalds atomic_set(&n->users, 1); 5021da177e4SLinus Torvalds C(head); 5031da177e4SLinus Torvalds C(data); 5041da177e4SLinus Torvalds C(tail); 5051da177e4SLinus Torvalds C(end); 5061da177e4SLinus Torvalds 5071da177e4SLinus Torvalds atomic_inc(&(skb_shinfo(skb)->dataref)); 5081da177e4SLinus Torvalds skb->cloned = 1; 5091da177e4SLinus Torvalds 5101da177e4SLinus Torvalds return n; 5111da177e4SLinus Torvalds } 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 5141da177e4SLinus Torvalds { 5151da177e4SLinus Torvalds /* 5161da177e4SLinus Torvalds * Shift between the two data areas in bytes 5171da177e4SLinus Torvalds */ 5181da177e4SLinus Torvalds unsigned long offset = new->data - old->data; 5191da177e4SLinus Torvalds 5201da177e4SLinus Torvalds new->sk = NULL; 5211da177e4SLinus Torvalds new->dev = old->dev; 5221da177e4SLinus Torvalds new->priority = old->priority; 5231da177e4SLinus Torvalds new->protocol = old->protocol; 5241da177e4SLinus Torvalds new->dst = dst_clone(old->dst); 5251da177e4SLinus Torvalds #ifdef CONFIG_INET 5261da177e4SLinus Torvalds new->sp = secpath_get(old->sp); 5271da177e4SLinus Torvalds #endif 5281da177e4SLinus Torvalds new->h.raw = old->h.raw + offset; 5291da177e4SLinus Torvalds new->nh.raw = old->nh.raw + offset; 5301da177e4SLinus Torvalds new->mac.raw = old->mac.raw + offset; 5311da177e4SLinus Torvalds memcpy(new->cb, old->cb, sizeof(old->cb)); 5321da177e4SLinus Torvalds new->local_df = old->local_df; 533d179cd12SDavid S. Miller new->fclone = SKB_FCLONE_UNAVAILABLE; 5341da177e4SLinus Torvalds new->pkt_type = old->pkt_type; 535a61bbcf2SPatrick McHardy new->tstamp = old->tstamp; 5361da177e4SLinus Torvalds new->destructor = NULL; 5371da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 5381da177e4SLinus Torvalds new->nfmark = old->nfmark; 5391da177e4SLinus Torvalds new->nfct = old->nfct; 5401da177e4SLinus Torvalds nf_conntrack_get(old->nfct); 5411da177e4SLinus Torvalds new->nfctinfo = old->nfctinfo; 5429fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 5439fb9cbb1SYasuyuki Kozakai new->nfct_reasm = old->nfct_reasm; 5449fb9cbb1SYasuyuki Kozakai nf_conntrack_get_reasm(old->nfct_reasm); 5459fb9cbb1SYasuyuki Kozakai #endif 546c98d80edSJulian Anastasov #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 547c98d80edSJulian Anastasov new->ipvs_property = old->ipvs_property; 548c98d80edSJulian Anastasov #endif 5491da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 5501da177e4SLinus Torvalds new->nf_bridge = old->nf_bridge; 5511da177e4SLinus Torvalds nf_bridge_get(old->nf_bridge); 5521da177e4SLinus Torvalds #endif 5531da177e4SLinus Torvalds #endif 5541da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 5551da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 5561da177e4SLinus Torvalds new->tc_verd = old->tc_verd; 5571da177e4SLinus Torvalds #endif 5581da177e4SLinus Torvalds new->tc_index = old->tc_index; 5591da177e4SLinus Torvalds #endif 560984bc16cSJames Morris skb_copy_secmark(new, old); 5611da177e4SLinus Torvalds atomic_set(&new->users, 1); 5627967168cSHerbert Xu skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; 5637967168cSHerbert Xu skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; 5647967168cSHerbert Xu skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; 5651da177e4SLinus Torvalds } 5661da177e4SLinus Torvalds 5671da177e4SLinus Torvalds /** 5681da177e4SLinus Torvalds * skb_copy - create private copy of an sk_buff 5691da177e4SLinus Torvalds * @skb: buffer to copy 5701da177e4SLinus Torvalds * @gfp_mask: allocation priority 5711da177e4SLinus Torvalds * 5721da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data. This is used when the 5731da177e4SLinus Torvalds * caller wishes to modify the data and needs a private copy of the 5741da177e4SLinus Torvalds * data to alter. Returns %NULL on failure or the pointer to the buffer 5751da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 5761da177e4SLinus Torvalds * 5771da177e4SLinus Torvalds * As by-product this function converts non-linear &sk_buff to linear 5781da177e4SLinus Torvalds * one, so that &sk_buff becomes completely private and caller is allowed 5791da177e4SLinus Torvalds * to modify all the data of returned buffer. This means that this 5801da177e4SLinus Torvalds * function is not recommended for use in circumstances when only 5811da177e4SLinus Torvalds * header is going to be modified. Use pskb_copy() instead. 5821da177e4SLinus Torvalds */ 5831da177e4SLinus Torvalds 584dd0fc66fSAl Viro struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) 5851da177e4SLinus Torvalds { 5861da177e4SLinus Torvalds int headerlen = skb->data - skb->head; 5871da177e4SLinus Torvalds /* 5881da177e4SLinus Torvalds * Allocate the copy buffer 5891da177e4SLinus Torvalds */ 5901da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len, 5911da177e4SLinus Torvalds gfp_mask); 5921da177e4SLinus Torvalds if (!n) 5931da177e4SLinus Torvalds return NULL; 5941da177e4SLinus Torvalds 5951da177e4SLinus Torvalds /* Set the data pointer */ 5961da177e4SLinus Torvalds skb_reserve(n, headerlen); 5971da177e4SLinus Torvalds /* Set the tail pointer and length */ 5981da177e4SLinus Torvalds skb_put(n, skb->len); 5991da177e4SLinus Torvalds n->csum = skb->csum; 6001da177e4SLinus Torvalds n->ip_summed = skb->ip_summed; 6011da177e4SLinus Torvalds 6021da177e4SLinus Torvalds if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) 6031da177e4SLinus Torvalds BUG(); 6041da177e4SLinus Torvalds 6051da177e4SLinus Torvalds copy_skb_header(n, skb); 6061da177e4SLinus Torvalds return n; 6071da177e4SLinus Torvalds } 6081da177e4SLinus Torvalds 6091da177e4SLinus Torvalds 6101da177e4SLinus Torvalds /** 6111da177e4SLinus Torvalds * pskb_copy - create copy of an sk_buff with private head. 6121da177e4SLinus Torvalds * @skb: buffer to copy 6131da177e4SLinus Torvalds * @gfp_mask: allocation priority 6141da177e4SLinus Torvalds * 6151da177e4SLinus Torvalds * Make a copy of both an &sk_buff and part of its data, located 6161da177e4SLinus Torvalds * in header. Fragmented data remain shared. This is used when 6171da177e4SLinus Torvalds * the caller wishes to modify only header of &sk_buff and needs 6181da177e4SLinus Torvalds * private copy of the header to alter. Returns %NULL on failure 6191da177e4SLinus Torvalds * or the pointer to the buffer on success. 6201da177e4SLinus Torvalds * The returned buffer has a reference count of 1. 6211da177e4SLinus Torvalds */ 6221da177e4SLinus Torvalds 623dd0fc66fSAl Viro struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask) 6241da177e4SLinus Torvalds { 6251da177e4SLinus Torvalds /* 6261da177e4SLinus Torvalds * Allocate the copy buffer 6271da177e4SLinus Torvalds */ 6281da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask); 6291da177e4SLinus Torvalds 6301da177e4SLinus Torvalds if (!n) 6311da177e4SLinus Torvalds goto out; 6321da177e4SLinus Torvalds 6331da177e4SLinus Torvalds /* Set the data pointer */ 6341da177e4SLinus Torvalds skb_reserve(n, skb->data - skb->head); 6351da177e4SLinus Torvalds /* Set the tail pointer and length */ 6361da177e4SLinus Torvalds skb_put(n, skb_headlen(skb)); 6371da177e4SLinus Torvalds /* Copy the bytes */ 6381da177e4SLinus Torvalds memcpy(n->data, skb->data, n->len); 6391da177e4SLinus Torvalds n->csum = skb->csum; 6401da177e4SLinus Torvalds n->ip_summed = skb->ip_summed; 6411da177e4SLinus Torvalds 6421da177e4SLinus Torvalds n->data_len = skb->data_len; 6431da177e4SLinus Torvalds n->len = skb->len; 6441da177e4SLinus Torvalds 6451da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 6461da177e4SLinus Torvalds int i; 6471da177e4SLinus Torvalds 6481da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 6491da177e4SLinus Torvalds skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; 6501da177e4SLinus Torvalds get_page(skb_shinfo(n)->frags[i].page); 6511da177e4SLinus Torvalds } 6521da177e4SLinus Torvalds skb_shinfo(n)->nr_frags = i; 6531da177e4SLinus Torvalds } 6541da177e4SLinus Torvalds 6551da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 6561da177e4SLinus Torvalds skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; 6571da177e4SLinus Torvalds skb_clone_fraglist(n); 6581da177e4SLinus Torvalds } 6591da177e4SLinus Torvalds 6601da177e4SLinus Torvalds copy_skb_header(n, skb); 6611da177e4SLinus Torvalds out: 6621da177e4SLinus Torvalds return n; 6631da177e4SLinus Torvalds } 6641da177e4SLinus Torvalds 6651da177e4SLinus Torvalds /** 6661da177e4SLinus Torvalds * pskb_expand_head - reallocate header of &sk_buff 6671da177e4SLinus Torvalds * @skb: buffer to reallocate 6681da177e4SLinus Torvalds * @nhead: room to add at head 6691da177e4SLinus Torvalds * @ntail: room to add at tail 6701da177e4SLinus Torvalds * @gfp_mask: allocation priority 6711da177e4SLinus Torvalds * 6721da177e4SLinus Torvalds * Expands (or creates identical copy, if &nhead and &ntail are zero) 6731da177e4SLinus Torvalds * header of skb. &sk_buff itself is not changed. &sk_buff MUST have 6741da177e4SLinus Torvalds * reference count of 1. Returns zero in the case of success or error, 6751da177e4SLinus Torvalds * if expansion failed. In the last case, &sk_buff is not changed. 6761da177e4SLinus Torvalds * 6771da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 6781da177e4SLinus Torvalds * reloaded after call to this function. 6791da177e4SLinus Torvalds */ 6801da177e4SLinus Torvalds 68186a76cafSVictor Fusco int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, 682dd0fc66fSAl Viro gfp_t gfp_mask) 6831da177e4SLinus Torvalds { 6841da177e4SLinus Torvalds int i; 6851da177e4SLinus Torvalds u8 *data; 6861da177e4SLinus Torvalds int size = nhead + (skb->end - skb->head) + ntail; 6871da177e4SLinus Torvalds long off; 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds if (skb_shared(skb)) 6901da177e4SLinus Torvalds BUG(); 6911da177e4SLinus Torvalds 6921da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 6931da177e4SLinus Torvalds 6941da177e4SLinus Torvalds data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); 6951da177e4SLinus Torvalds if (!data) 6961da177e4SLinus Torvalds goto nodata; 6971da177e4SLinus Torvalds 6981da177e4SLinus Torvalds /* Copy only real data... and, alas, header. This should be 6991da177e4SLinus Torvalds * optimized for the cases when header is void. */ 7001da177e4SLinus Torvalds memcpy(data + nhead, skb->head, skb->tail - skb->head); 7011da177e4SLinus Torvalds memcpy(data + size, skb->end, sizeof(struct skb_shared_info)); 7021da177e4SLinus Torvalds 7031da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 7041da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 7051da177e4SLinus Torvalds 7061da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 7071da177e4SLinus Torvalds skb_clone_fraglist(skb); 7081da177e4SLinus Torvalds 7091da177e4SLinus Torvalds skb_release_data(skb); 7101da177e4SLinus Torvalds 7111da177e4SLinus Torvalds off = (data + nhead) - skb->head; 7121da177e4SLinus Torvalds 7131da177e4SLinus Torvalds skb->head = data; 7141da177e4SLinus Torvalds skb->end = data + size; 7151da177e4SLinus Torvalds skb->data += off; 7161da177e4SLinus Torvalds skb->tail += off; 7171da177e4SLinus Torvalds skb->mac.raw += off; 7181da177e4SLinus Torvalds skb->h.raw += off; 7191da177e4SLinus Torvalds skb->nh.raw += off; 7201da177e4SLinus Torvalds skb->cloned = 0; 7211da177e4SLinus Torvalds skb->nohdr = 0; 7221da177e4SLinus Torvalds atomic_set(&skb_shinfo(skb)->dataref, 1); 7231da177e4SLinus Torvalds return 0; 7241da177e4SLinus Torvalds 7251da177e4SLinus Torvalds nodata: 7261da177e4SLinus Torvalds return -ENOMEM; 7271da177e4SLinus Torvalds } 7281da177e4SLinus Torvalds 7291da177e4SLinus Torvalds /* Make private copy of skb with writable head and some headroom */ 7301da177e4SLinus Torvalds 7311da177e4SLinus Torvalds struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) 7321da177e4SLinus Torvalds { 7331da177e4SLinus Torvalds struct sk_buff *skb2; 7341da177e4SLinus Torvalds int delta = headroom - skb_headroom(skb); 7351da177e4SLinus Torvalds 7361da177e4SLinus Torvalds if (delta <= 0) 7371da177e4SLinus Torvalds skb2 = pskb_copy(skb, GFP_ATOMIC); 7381da177e4SLinus Torvalds else { 7391da177e4SLinus Torvalds skb2 = skb_clone(skb, GFP_ATOMIC); 7401da177e4SLinus Torvalds if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, 7411da177e4SLinus Torvalds GFP_ATOMIC)) { 7421da177e4SLinus Torvalds kfree_skb(skb2); 7431da177e4SLinus Torvalds skb2 = NULL; 7441da177e4SLinus Torvalds } 7451da177e4SLinus Torvalds } 7461da177e4SLinus Torvalds return skb2; 7471da177e4SLinus Torvalds } 7481da177e4SLinus Torvalds 7491da177e4SLinus Torvalds 7501da177e4SLinus Torvalds /** 7511da177e4SLinus Torvalds * skb_copy_expand - copy and expand sk_buff 7521da177e4SLinus Torvalds * @skb: buffer to copy 7531da177e4SLinus Torvalds * @newheadroom: new free bytes at head 7541da177e4SLinus Torvalds * @newtailroom: new free bytes at tail 7551da177e4SLinus Torvalds * @gfp_mask: allocation priority 7561da177e4SLinus Torvalds * 7571da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data and while doing so 7581da177e4SLinus Torvalds * allocate additional space. 7591da177e4SLinus Torvalds * 7601da177e4SLinus Torvalds * This is used when the caller wishes to modify the data and needs a 7611da177e4SLinus Torvalds * private copy of the data to alter as well as more space for new fields. 7621da177e4SLinus Torvalds * Returns %NULL on failure or the pointer to the buffer 7631da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 7641da177e4SLinus Torvalds * 7651da177e4SLinus Torvalds * You must pass %GFP_ATOMIC as the allocation priority if this function 7661da177e4SLinus Torvalds * is called from an interrupt. 7671da177e4SLinus Torvalds * 7681da177e4SLinus Torvalds * BUG ALERT: ip_summed is not copied. Why does this work? Is it used 7691da177e4SLinus Torvalds * only by netfilter in the cases when checksum is recalculated? --ANK 7701da177e4SLinus Torvalds */ 7711da177e4SLinus Torvalds struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 77286a76cafSVictor Fusco int newheadroom, int newtailroom, 773dd0fc66fSAl Viro gfp_t gfp_mask) 7741da177e4SLinus Torvalds { 7751da177e4SLinus Torvalds /* 7761da177e4SLinus Torvalds * Allocate the copy buffer 7771da177e4SLinus Torvalds */ 7781da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, 7791da177e4SLinus Torvalds gfp_mask); 7801da177e4SLinus Torvalds int head_copy_len, head_copy_off; 7811da177e4SLinus Torvalds 7821da177e4SLinus Torvalds if (!n) 7831da177e4SLinus Torvalds return NULL; 7841da177e4SLinus Torvalds 7851da177e4SLinus Torvalds skb_reserve(n, newheadroom); 7861da177e4SLinus Torvalds 7871da177e4SLinus Torvalds /* Set the tail pointer and length */ 7881da177e4SLinus Torvalds skb_put(n, skb->len); 7891da177e4SLinus Torvalds 7901da177e4SLinus Torvalds head_copy_len = skb_headroom(skb); 7911da177e4SLinus Torvalds head_copy_off = 0; 7921da177e4SLinus Torvalds if (newheadroom <= head_copy_len) 7931da177e4SLinus Torvalds head_copy_len = newheadroom; 7941da177e4SLinus Torvalds else 7951da177e4SLinus Torvalds head_copy_off = newheadroom - head_copy_len; 7961da177e4SLinus Torvalds 7971da177e4SLinus Torvalds /* Copy the linear header and data. */ 7981da177e4SLinus Torvalds if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, 7991da177e4SLinus Torvalds skb->len + head_copy_len)) 8001da177e4SLinus Torvalds BUG(); 8011da177e4SLinus Torvalds 8021da177e4SLinus Torvalds copy_skb_header(n, skb); 8031da177e4SLinus Torvalds 8041da177e4SLinus Torvalds return n; 8051da177e4SLinus Torvalds } 8061da177e4SLinus Torvalds 8071da177e4SLinus Torvalds /** 8081da177e4SLinus Torvalds * skb_pad - zero pad the tail of an skb 8091da177e4SLinus Torvalds * @skb: buffer to pad 8101da177e4SLinus Torvalds * @pad: space to pad 8111da177e4SLinus Torvalds * 8121da177e4SLinus Torvalds * Ensure that a buffer is followed by a padding area that is zero 8131da177e4SLinus Torvalds * filled. Used by network drivers which may DMA or transfer data 8141da177e4SLinus Torvalds * beyond the buffer end onto the wire. 8151da177e4SLinus Torvalds * 8165b057c6bSHerbert Xu * May return error in out of memory cases. The skb is freed on error. 8171da177e4SLinus Torvalds */ 8181da177e4SLinus Torvalds 8195b057c6bSHerbert Xu int skb_pad(struct sk_buff *skb, int pad) 8201da177e4SLinus Torvalds { 8215b057c6bSHerbert Xu int err; 8225b057c6bSHerbert Xu int ntail; 8231da177e4SLinus Torvalds 8241da177e4SLinus Torvalds /* If the skbuff is non linear tailroom is always zero.. */ 8255b057c6bSHerbert Xu if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { 8261da177e4SLinus Torvalds memset(skb->data+skb->len, 0, pad); 8275b057c6bSHerbert Xu return 0; 8281da177e4SLinus Torvalds } 8291da177e4SLinus Torvalds 8305b057c6bSHerbert Xu ntail = skb->data_len + pad - (skb->end - skb->tail); 8315b057c6bSHerbert Xu if (likely(skb_cloned(skb) || ntail > 0)) { 8325b057c6bSHerbert Xu err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); 8335b057c6bSHerbert Xu if (unlikely(err)) 8345b057c6bSHerbert Xu goto free_skb; 8355b057c6bSHerbert Xu } 8365b057c6bSHerbert Xu 8375b057c6bSHerbert Xu /* FIXME: The use of this function with non-linear skb's really needs 8385b057c6bSHerbert Xu * to be audited. 8395b057c6bSHerbert Xu */ 8405b057c6bSHerbert Xu err = skb_linearize(skb); 8415b057c6bSHerbert Xu if (unlikely(err)) 8425b057c6bSHerbert Xu goto free_skb; 8435b057c6bSHerbert Xu 8445b057c6bSHerbert Xu memset(skb->data + skb->len, 0, pad); 8455b057c6bSHerbert Xu return 0; 8465b057c6bSHerbert Xu 8475b057c6bSHerbert Xu free_skb: 8481da177e4SLinus Torvalds kfree_skb(skb); 8495b057c6bSHerbert Xu return err; 8501da177e4SLinus Torvalds } 8511da177e4SLinus Torvalds 8523cc0e873SHerbert Xu /* Trims skb to length len. It can change skb pointers. 8531da177e4SLinus Torvalds */ 8541da177e4SLinus Torvalds 8553cc0e873SHerbert Xu int ___pskb_trim(struct sk_buff *skb, unsigned int len) 8561da177e4SLinus Torvalds { 85727b437c8SHerbert Xu struct sk_buff **fragp; 85827b437c8SHerbert Xu struct sk_buff *frag; 8591da177e4SLinus Torvalds int offset = skb_headlen(skb); 8601da177e4SLinus Torvalds int nfrags = skb_shinfo(skb)->nr_frags; 8611da177e4SLinus Torvalds int i; 86227b437c8SHerbert Xu int err; 86327b437c8SHerbert Xu 86427b437c8SHerbert Xu if (skb_cloned(skb) && 86527b437c8SHerbert Xu unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) 86627b437c8SHerbert Xu return err; 8671da177e4SLinus Torvalds 868f4d26fb3SHerbert Xu i = 0; 869f4d26fb3SHerbert Xu if (offset >= len) 870f4d26fb3SHerbert Xu goto drop_pages; 871f4d26fb3SHerbert Xu 872f4d26fb3SHerbert Xu for (; i < nfrags; i++) { 8731da177e4SLinus Torvalds int end = offset + skb_shinfo(skb)->frags[i].size; 87427b437c8SHerbert Xu 87527b437c8SHerbert Xu if (end < len) { 8761da177e4SLinus Torvalds offset = end; 87727b437c8SHerbert Xu continue; 8781da177e4SLinus Torvalds } 8791da177e4SLinus Torvalds 88027b437c8SHerbert Xu skb_shinfo(skb)->frags[i++].size = len - offset; 88127b437c8SHerbert Xu 882f4d26fb3SHerbert Xu drop_pages: 88327b437c8SHerbert Xu skb_shinfo(skb)->nr_frags = i; 88427b437c8SHerbert Xu 88527b437c8SHerbert Xu for (; i < nfrags; i++) 88627b437c8SHerbert Xu put_page(skb_shinfo(skb)->frags[i].page); 88727b437c8SHerbert Xu 88827b437c8SHerbert Xu if (skb_shinfo(skb)->frag_list) 88927b437c8SHerbert Xu skb_drop_fraglist(skb); 890f4d26fb3SHerbert Xu goto done; 89127b437c8SHerbert Xu } 89227b437c8SHerbert Xu 89327b437c8SHerbert Xu for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); 89427b437c8SHerbert Xu fragp = &frag->next) { 89527b437c8SHerbert Xu int end = offset + frag->len; 89627b437c8SHerbert Xu 89727b437c8SHerbert Xu if (skb_shared(frag)) { 89827b437c8SHerbert Xu struct sk_buff *nfrag; 89927b437c8SHerbert Xu 90027b437c8SHerbert Xu nfrag = skb_clone(frag, GFP_ATOMIC); 90127b437c8SHerbert Xu if (unlikely(!nfrag)) 90227b437c8SHerbert Xu return -ENOMEM; 90327b437c8SHerbert Xu 90427b437c8SHerbert Xu nfrag->next = frag->next; 905f4d26fb3SHerbert Xu kfree_skb(frag); 90627b437c8SHerbert Xu frag = nfrag; 90727b437c8SHerbert Xu *fragp = frag; 90827b437c8SHerbert Xu } 90927b437c8SHerbert Xu 91027b437c8SHerbert Xu if (end < len) { 91127b437c8SHerbert Xu offset = end; 91227b437c8SHerbert Xu continue; 91327b437c8SHerbert Xu } 91427b437c8SHerbert Xu 91527b437c8SHerbert Xu if (end > len && 91627b437c8SHerbert Xu unlikely((err = pskb_trim(frag, len - offset)))) 91727b437c8SHerbert Xu return err; 91827b437c8SHerbert Xu 91927b437c8SHerbert Xu if (frag->next) 92027b437c8SHerbert Xu skb_drop_list(&frag->next); 92127b437c8SHerbert Xu break; 92227b437c8SHerbert Xu } 92327b437c8SHerbert Xu 924f4d26fb3SHerbert Xu done: 92527b437c8SHerbert Xu if (len > skb_headlen(skb)) { 9261da177e4SLinus Torvalds skb->data_len -= skb->len - len; 9271da177e4SLinus Torvalds skb->len = len; 9281da177e4SLinus Torvalds } else { 9291da177e4SLinus Torvalds skb->len = len; 9301da177e4SLinus Torvalds skb->data_len = 0; 9311da177e4SLinus Torvalds skb->tail = skb->data + len; 9321da177e4SLinus Torvalds } 9331da177e4SLinus Torvalds 9341da177e4SLinus Torvalds return 0; 9351da177e4SLinus Torvalds } 9361da177e4SLinus Torvalds 9371da177e4SLinus Torvalds /** 9381da177e4SLinus Torvalds * __pskb_pull_tail - advance tail of skb header 9391da177e4SLinus Torvalds * @skb: buffer to reallocate 9401da177e4SLinus Torvalds * @delta: number of bytes to advance tail 9411da177e4SLinus Torvalds * 9421da177e4SLinus Torvalds * The function makes a sense only on a fragmented &sk_buff, 9431da177e4SLinus Torvalds * it expands header moving its tail forward and copying necessary 9441da177e4SLinus Torvalds * data from fragmented part. 9451da177e4SLinus Torvalds * 9461da177e4SLinus Torvalds * &sk_buff MUST have reference count of 1. 9471da177e4SLinus Torvalds * 9481da177e4SLinus Torvalds * Returns %NULL (and &sk_buff does not change) if pull failed 9491da177e4SLinus Torvalds * or value of new tail of skb in the case of success. 9501da177e4SLinus Torvalds * 9511da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 9521da177e4SLinus Torvalds * reloaded after call to this function. 9531da177e4SLinus Torvalds */ 9541da177e4SLinus Torvalds 9551da177e4SLinus Torvalds /* Moves tail of skb head forward, copying data from fragmented part, 9561da177e4SLinus Torvalds * when it is necessary. 9571da177e4SLinus Torvalds * 1. It may fail due to malloc failure. 9581da177e4SLinus Torvalds * 2. It may change skb pointers. 9591da177e4SLinus Torvalds * 9601da177e4SLinus Torvalds * It is pretty complicated. Luckily, it is called only in exceptional cases. 9611da177e4SLinus Torvalds */ 9621da177e4SLinus Torvalds unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) 9631da177e4SLinus Torvalds { 9641da177e4SLinus Torvalds /* If skb has not enough free space at tail, get new one 9651da177e4SLinus Torvalds * plus 128 bytes for future expansions. If we have enough 9661da177e4SLinus Torvalds * room at tail, reallocate without expansion only if skb is cloned. 9671da177e4SLinus Torvalds */ 9681da177e4SLinus Torvalds int i, k, eat = (skb->tail + delta) - skb->end; 9691da177e4SLinus Torvalds 9701da177e4SLinus Torvalds if (eat > 0 || skb_cloned(skb)) { 9711da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, 9721da177e4SLinus Torvalds GFP_ATOMIC)) 9731da177e4SLinus Torvalds return NULL; 9741da177e4SLinus Torvalds } 9751da177e4SLinus Torvalds 9761da177e4SLinus Torvalds if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta)) 9771da177e4SLinus Torvalds BUG(); 9781da177e4SLinus Torvalds 9791da177e4SLinus Torvalds /* Optimization: no fragments, no reasons to preestimate 9801da177e4SLinus Torvalds * size of pulled pages. Superb. 9811da177e4SLinus Torvalds */ 9821da177e4SLinus Torvalds if (!skb_shinfo(skb)->frag_list) 9831da177e4SLinus Torvalds goto pull_pages; 9841da177e4SLinus Torvalds 9851da177e4SLinus Torvalds /* Estimate size of pulled pages. */ 9861da177e4SLinus Torvalds eat = delta; 9871da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 9881da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size >= eat) 9891da177e4SLinus Torvalds goto pull_pages; 9901da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 9911da177e4SLinus Torvalds } 9921da177e4SLinus Torvalds 9931da177e4SLinus Torvalds /* If we need update frag list, we are in troubles. 9941da177e4SLinus Torvalds * Certainly, it possible to add an offset to skb data, 9951da177e4SLinus Torvalds * but taking into account that pulling is expected to 9961da177e4SLinus Torvalds * be very rare operation, it is worth to fight against 9971da177e4SLinus Torvalds * further bloating skb head and crucify ourselves here instead. 9981da177e4SLinus Torvalds * Pure masohism, indeed. 8)8) 9991da177e4SLinus Torvalds */ 10001da177e4SLinus Torvalds if (eat) { 10011da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 10021da177e4SLinus Torvalds struct sk_buff *clone = NULL; 10031da177e4SLinus Torvalds struct sk_buff *insp = NULL; 10041da177e4SLinus Torvalds 10051da177e4SLinus Torvalds do { 100609a62660SKris Katterjohn BUG_ON(!list); 10071da177e4SLinus Torvalds 10081da177e4SLinus Torvalds if (list->len <= eat) { 10091da177e4SLinus Torvalds /* Eaten as whole. */ 10101da177e4SLinus Torvalds eat -= list->len; 10111da177e4SLinus Torvalds list = list->next; 10121da177e4SLinus Torvalds insp = list; 10131da177e4SLinus Torvalds } else { 10141da177e4SLinus Torvalds /* Eaten partially. */ 10151da177e4SLinus Torvalds 10161da177e4SLinus Torvalds if (skb_shared(list)) { 10171da177e4SLinus Torvalds /* Sucks! We need to fork list. :-( */ 10181da177e4SLinus Torvalds clone = skb_clone(list, GFP_ATOMIC); 10191da177e4SLinus Torvalds if (!clone) 10201da177e4SLinus Torvalds return NULL; 10211da177e4SLinus Torvalds insp = list->next; 10221da177e4SLinus Torvalds list = clone; 10231da177e4SLinus Torvalds } else { 10241da177e4SLinus Torvalds /* This may be pulled without 10251da177e4SLinus Torvalds * problems. */ 10261da177e4SLinus Torvalds insp = list; 10271da177e4SLinus Torvalds } 10281da177e4SLinus Torvalds if (!pskb_pull(list, eat)) { 10291da177e4SLinus Torvalds if (clone) 10301da177e4SLinus Torvalds kfree_skb(clone); 10311da177e4SLinus Torvalds return NULL; 10321da177e4SLinus Torvalds } 10331da177e4SLinus Torvalds break; 10341da177e4SLinus Torvalds } 10351da177e4SLinus Torvalds } while (eat); 10361da177e4SLinus Torvalds 10371da177e4SLinus Torvalds /* Free pulled out fragments. */ 10381da177e4SLinus Torvalds while ((list = skb_shinfo(skb)->frag_list) != insp) { 10391da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = list->next; 10401da177e4SLinus Torvalds kfree_skb(list); 10411da177e4SLinus Torvalds } 10421da177e4SLinus Torvalds /* And insert new clone at head. */ 10431da177e4SLinus Torvalds if (clone) { 10441da177e4SLinus Torvalds clone->next = list; 10451da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = clone; 10461da177e4SLinus Torvalds } 10471da177e4SLinus Torvalds } 10481da177e4SLinus Torvalds /* Success! Now we may commit changes to skb data. */ 10491da177e4SLinus Torvalds 10501da177e4SLinus Torvalds pull_pages: 10511da177e4SLinus Torvalds eat = delta; 10521da177e4SLinus Torvalds k = 0; 10531da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 10541da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size <= eat) { 10551da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 10561da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 10571da177e4SLinus Torvalds } else { 10581da177e4SLinus Torvalds skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; 10591da177e4SLinus Torvalds if (eat) { 10601da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].page_offset += eat; 10611da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].size -= eat; 10621da177e4SLinus Torvalds eat = 0; 10631da177e4SLinus Torvalds } 10641da177e4SLinus Torvalds k++; 10651da177e4SLinus Torvalds } 10661da177e4SLinus Torvalds } 10671da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = k; 10681da177e4SLinus Torvalds 10691da177e4SLinus Torvalds skb->tail += delta; 10701da177e4SLinus Torvalds skb->data_len -= delta; 10711da177e4SLinus Torvalds 10721da177e4SLinus Torvalds return skb->tail; 10731da177e4SLinus Torvalds } 10741da177e4SLinus Torvalds 10751da177e4SLinus Torvalds /* Copy some data bits from skb to kernel buffer. */ 10761da177e4SLinus Torvalds 10771da177e4SLinus Torvalds int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) 10781da177e4SLinus Torvalds { 10791da177e4SLinus Torvalds int i, copy; 10801da177e4SLinus Torvalds int start = skb_headlen(skb); 10811da177e4SLinus Torvalds 10821da177e4SLinus Torvalds if (offset > (int)skb->len - len) 10831da177e4SLinus Torvalds goto fault; 10841da177e4SLinus Torvalds 10851da177e4SLinus Torvalds /* Copy header. */ 10861da177e4SLinus Torvalds if ((copy = start - offset) > 0) { 10871da177e4SLinus Torvalds if (copy > len) 10881da177e4SLinus Torvalds copy = len; 10891da177e4SLinus Torvalds memcpy(to, skb->data + offset, copy); 10901da177e4SLinus Torvalds if ((len -= copy) == 0) 10911da177e4SLinus Torvalds return 0; 10921da177e4SLinus Torvalds offset += copy; 10931da177e4SLinus Torvalds to += copy; 10941da177e4SLinus Torvalds } 10951da177e4SLinus Torvalds 10961da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 10971da177e4SLinus Torvalds int end; 10981da177e4SLinus Torvalds 10991da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 11001da177e4SLinus Torvalds 11011da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 11021da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 11031da177e4SLinus Torvalds u8 *vaddr; 11041da177e4SLinus Torvalds 11051da177e4SLinus Torvalds if (copy > len) 11061da177e4SLinus Torvalds copy = len; 11071da177e4SLinus Torvalds 11081da177e4SLinus Torvalds vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); 11091da177e4SLinus Torvalds memcpy(to, 11101da177e4SLinus Torvalds vaddr + skb_shinfo(skb)->frags[i].page_offset+ 11111da177e4SLinus Torvalds offset - start, copy); 11121da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 11131da177e4SLinus Torvalds 11141da177e4SLinus Torvalds if ((len -= copy) == 0) 11151da177e4SLinus Torvalds return 0; 11161da177e4SLinus Torvalds offset += copy; 11171da177e4SLinus Torvalds to += copy; 11181da177e4SLinus Torvalds } 11191da177e4SLinus Torvalds start = end; 11201da177e4SLinus Torvalds } 11211da177e4SLinus Torvalds 11221da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 11231da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 11241da177e4SLinus Torvalds 11251da177e4SLinus Torvalds for (; list; list = list->next) { 11261da177e4SLinus Torvalds int end; 11271da177e4SLinus Torvalds 11281da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 11291da177e4SLinus Torvalds 11301da177e4SLinus Torvalds end = start + list->len; 11311da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 11321da177e4SLinus Torvalds if (copy > len) 11331da177e4SLinus Torvalds copy = len; 11341da177e4SLinus Torvalds if (skb_copy_bits(list, offset - start, 11351da177e4SLinus Torvalds to, copy)) 11361da177e4SLinus Torvalds goto fault; 11371da177e4SLinus Torvalds if ((len -= copy) == 0) 11381da177e4SLinus Torvalds return 0; 11391da177e4SLinus Torvalds offset += copy; 11401da177e4SLinus Torvalds to += copy; 11411da177e4SLinus Torvalds } 11421da177e4SLinus Torvalds start = end; 11431da177e4SLinus Torvalds } 11441da177e4SLinus Torvalds } 11451da177e4SLinus Torvalds if (!len) 11461da177e4SLinus Torvalds return 0; 11471da177e4SLinus Torvalds 11481da177e4SLinus Torvalds fault: 11491da177e4SLinus Torvalds return -EFAULT; 11501da177e4SLinus Torvalds } 11511da177e4SLinus Torvalds 1152357b40a1SHerbert Xu /** 1153357b40a1SHerbert Xu * skb_store_bits - store bits from kernel buffer to skb 1154357b40a1SHerbert Xu * @skb: destination buffer 1155357b40a1SHerbert Xu * @offset: offset in destination 1156357b40a1SHerbert Xu * @from: source buffer 1157357b40a1SHerbert Xu * @len: number of bytes to copy 1158357b40a1SHerbert Xu * 1159357b40a1SHerbert Xu * Copy the specified number of bytes from the source buffer to the 1160357b40a1SHerbert Xu * destination skb. This function handles all the messy bits of 1161357b40a1SHerbert Xu * traversing fragment lists and such. 1162357b40a1SHerbert Xu */ 1163357b40a1SHerbert Xu 1164357b40a1SHerbert Xu int skb_store_bits(const struct sk_buff *skb, int offset, void *from, int len) 1165357b40a1SHerbert Xu { 1166357b40a1SHerbert Xu int i, copy; 1167357b40a1SHerbert Xu int start = skb_headlen(skb); 1168357b40a1SHerbert Xu 1169357b40a1SHerbert Xu if (offset > (int)skb->len - len) 1170357b40a1SHerbert Xu goto fault; 1171357b40a1SHerbert Xu 1172357b40a1SHerbert Xu if ((copy = start - offset) > 0) { 1173357b40a1SHerbert Xu if (copy > len) 1174357b40a1SHerbert Xu copy = len; 1175357b40a1SHerbert Xu memcpy(skb->data + offset, from, copy); 1176357b40a1SHerbert Xu if ((len -= copy) == 0) 1177357b40a1SHerbert Xu return 0; 1178357b40a1SHerbert Xu offset += copy; 1179357b40a1SHerbert Xu from += copy; 1180357b40a1SHerbert Xu } 1181357b40a1SHerbert Xu 1182357b40a1SHerbert Xu for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 1183357b40a1SHerbert Xu skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 1184357b40a1SHerbert Xu int end; 1185357b40a1SHerbert Xu 1186357b40a1SHerbert Xu BUG_TRAP(start <= offset + len); 1187357b40a1SHerbert Xu 1188357b40a1SHerbert Xu end = start + frag->size; 1189357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1190357b40a1SHerbert Xu u8 *vaddr; 1191357b40a1SHerbert Xu 1192357b40a1SHerbert Xu if (copy > len) 1193357b40a1SHerbert Xu copy = len; 1194357b40a1SHerbert Xu 1195357b40a1SHerbert Xu vaddr = kmap_skb_frag(frag); 1196357b40a1SHerbert Xu memcpy(vaddr + frag->page_offset + offset - start, 1197357b40a1SHerbert Xu from, copy); 1198357b40a1SHerbert Xu kunmap_skb_frag(vaddr); 1199357b40a1SHerbert Xu 1200357b40a1SHerbert Xu if ((len -= copy) == 0) 1201357b40a1SHerbert Xu return 0; 1202357b40a1SHerbert Xu offset += copy; 1203357b40a1SHerbert Xu from += copy; 1204357b40a1SHerbert Xu } 1205357b40a1SHerbert Xu start = end; 1206357b40a1SHerbert Xu } 1207357b40a1SHerbert Xu 1208357b40a1SHerbert Xu if (skb_shinfo(skb)->frag_list) { 1209357b40a1SHerbert Xu struct sk_buff *list = skb_shinfo(skb)->frag_list; 1210357b40a1SHerbert Xu 1211357b40a1SHerbert Xu for (; list; list = list->next) { 1212357b40a1SHerbert Xu int end; 1213357b40a1SHerbert Xu 1214357b40a1SHerbert Xu BUG_TRAP(start <= offset + len); 1215357b40a1SHerbert Xu 1216357b40a1SHerbert Xu end = start + list->len; 1217357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1218357b40a1SHerbert Xu if (copy > len) 1219357b40a1SHerbert Xu copy = len; 1220357b40a1SHerbert Xu if (skb_store_bits(list, offset - start, 1221357b40a1SHerbert Xu from, copy)) 1222357b40a1SHerbert Xu goto fault; 1223357b40a1SHerbert Xu if ((len -= copy) == 0) 1224357b40a1SHerbert Xu return 0; 1225357b40a1SHerbert Xu offset += copy; 1226357b40a1SHerbert Xu from += copy; 1227357b40a1SHerbert Xu } 1228357b40a1SHerbert Xu start = end; 1229357b40a1SHerbert Xu } 1230357b40a1SHerbert Xu } 1231357b40a1SHerbert Xu if (!len) 1232357b40a1SHerbert Xu return 0; 1233357b40a1SHerbert Xu 1234357b40a1SHerbert Xu fault: 1235357b40a1SHerbert Xu return -EFAULT; 1236357b40a1SHerbert Xu } 1237357b40a1SHerbert Xu 1238357b40a1SHerbert Xu EXPORT_SYMBOL(skb_store_bits); 1239357b40a1SHerbert Xu 12401da177e4SLinus Torvalds /* Checksum skb data. */ 12411da177e4SLinus Torvalds 12421da177e4SLinus Torvalds unsigned int skb_checksum(const struct sk_buff *skb, int offset, 12431da177e4SLinus Torvalds int len, unsigned int csum) 12441da177e4SLinus Torvalds { 12451da177e4SLinus Torvalds int start = skb_headlen(skb); 12461da177e4SLinus Torvalds int i, copy = start - offset; 12471da177e4SLinus Torvalds int pos = 0; 12481da177e4SLinus Torvalds 12491da177e4SLinus Torvalds /* Checksum header. */ 12501da177e4SLinus Torvalds if (copy > 0) { 12511da177e4SLinus Torvalds if (copy > len) 12521da177e4SLinus Torvalds copy = len; 12531da177e4SLinus Torvalds csum = csum_partial(skb->data + offset, copy, csum); 12541da177e4SLinus Torvalds if ((len -= copy) == 0) 12551da177e4SLinus Torvalds return csum; 12561da177e4SLinus Torvalds offset += copy; 12571da177e4SLinus Torvalds pos = copy; 12581da177e4SLinus Torvalds } 12591da177e4SLinus Torvalds 12601da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 12611da177e4SLinus Torvalds int end; 12621da177e4SLinus Torvalds 12631da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 12641da177e4SLinus Torvalds 12651da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 12661da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12671da177e4SLinus Torvalds unsigned int csum2; 12681da177e4SLinus Torvalds u8 *vaddr; 12691da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 12701da177e4SLinus Torvalds 12711da177e4SLinus Torvalds if (copy > len) 12721da177e4SLinus Torvalds copy = len; 12731da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 12741da177e4SLinus Torvalds csum2 = csum_partial(vaddr + frag->page_offset + 12751da177e4SLinus Torvalds offset - start, copy, 0); 12761da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 12771da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 12781da177e4SLinus Torvalds if (!(len -= copy)) 12791da177e4SLinus Torvalds return csum; 12801da177e4SLinus Torvalds offset += copy; 12811da177e4SLinus Torvalds pos += copy; 12821da177e4SLinus Torvalds } 12831da177e4SLinus Torvalds start = end; 12841da177e4SLinus Torvalds } 12851da177e4SLinus Torvalds 12861da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 12871da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 12881da177e4SLinus Torvalds 12891da177e4SLinus Torvalds for (; list; list = list->next) { 12901da177e4SLinus Torvalds int end; 12911da177e4SLinus Torvalds 12921da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 12931da177e4SLinus Torvalds 12941da177e4SLinus Torvalds end = start + list->len; 12951da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12961da177e4SLinus Torvalds unsigned int csum2; 12971da177e4SLinus Torvalds if (copy > len) 12981da177e4SLinus Torvalds copy = len; 12991da177e4SLinus Torvalds csum2 = skb_checksum(list, offset - start, 13001da177e4SLinus Torvalds copy, 0); 13011da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 13021da177e4SLinus Torvalds if ((len -= copy) == 0) 13031da177e4SLinus Torvalds return csum; 13041da177e4SLinus Torvalds offset += copy; 13051da177e4SLinus Torvalds pos += copy; 13061da177e4SLinus Torvalds } 13071da177e4SLinus Torvalds start = end; 13081da177e4SLinus Torvalds } 13091da177e4SLinus Torvalds } 131009a62660SKris Katterjohn BUG_ON(len); 13111da177e4SLinus Torvalds 13121da177e4SLinus Torvalds return csum; 13131da177e4SLinus Torvalds } 13141da177e4SLinus Torvalds 13151da177e4SLinus Torvalds /* Both of above in one bottle. */ 13161da177e4SLinus Torvalds 13171da177e4SLinus Torvalds unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 13181da177e4SLinus Torvalds u8 *to, int len, unsigned int csum) 13191da177e4SLinus Torvalds { 13201da177e4SLinus Torvalds int start = skb_headlen(skb); 13211da177e4SLinus Torvalds int i, copy = start - offset; 13221da177e4SLinus Torvalds int pos = 0; 13231da177e4SLinus Torvalds 13241da177e4SLinus Torvalds /* Copy header. */ 13251da177e4SLinus Torvalds if (copy > 0) { 13261da177e4SLinus Torvalds if (copy > len) 13271da177e4SLinus Torvalds copy = len; 13281da177e4SLinus Torvalds csum = csum_partial_copy_nocheck(skb->data + offset, to, 13291da177e4SLinus Torvalds copy, csum); 13301da177e4SLinus Torvalds if ((len -= copy) == 0) 13311da177e4SLinus Torvalds return csum; 13321da177e4SLinus Torvalds offset += copy; 13331da177e4SLinus Torvalds to += copy; 13341da177e4SLinus Torvalds pos = copy; 13351da177e4SLinus Torvalds } 13361da177e4SLinus Torvalds 13371da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 13381da177e4SLinus Torvalds int end; 13391da177e4SLinus Torvalds 13401da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 13411da177e4SLinus Torvalds 13421da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 13431da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 13441da177e4SLinus Torvalds unsigned int csum2; 13451da177e4SLinus Torvalds u8 *vaddr; 13461da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 13471da177e4SLinus Torvalds 13481da177e4SLinus Torvalds if (copy > len) 13491da177e4SLinus Torvalds copy = len; 13501da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 13511da177e4SLinus Torvalds csum2 = csum_partial_copy_nocheck(vaddr + 13521da177e4SLinus Torvalds frag->page_offset + 13531da177e4SLinus Torvalds offset - start, to, 13541da177e4SLinus Torvalds copy, 0); 13551da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 13561da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 13571da177e4SLinus Torvalds if (!(len -= copy)) 13581da177e4SLinus Torvalds return csum; 13591da177e4SLinus Torvalds offset += copy; 13601da177e4SLinus Torvalds to += copy; 13611da177e4SLinus Torvalds pos += copy; 13621da177e4SLinus Torvalds } 13631da177e4SLinus Torvalds start = end; 13641da177e4SLinus Torvalds } 13651da177e4SLinus Torvalds 13661da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 13671da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 13681da177e4SLinus Torvalds 13691da177e4SLinus Torvalds for (; list; list = list->next) { 13701da177e4SLinus Torvalds unsigned int csum2; 13711da177e4SLinus Torvalds int end; 13721da177e4SLinus Torvalds 13731da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 13741da177e4SLinus Torvalds 13751da177e4SLinus Torvalds end = start + list->len; 13761da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 13771da177e4SLinus Torvalds if (copy > len) 13781da177e4SLinus Torvalds copy = len; 13791da177e4SLinus Torvalds csum2 = skb_copy_and_csum_bits(list, 13801da177e4SLinus Torvalds offset - start, 13811da177e4SLinus Torvalds to, copy, 0); 13821da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 13831da177e4SLinus Torvalds if ((len -= copy) == 0) 13841da177e4SLinus Torvalds return csum; 13851da177e4SLinus Torvalds offset += copy; 13861da177e4SLinus Torvalds to += copy; 13871da177e4SLinus Torvalds pos += copy; 13881da177e4SLinus Torvalds } 13891da177e4SLinus Torvalds start = end; 13901da177e4SLinus Torvalds } 13911da177e4SLinus Torvalds } 139209a62660SKris Katterjohn BUG_ON(len); 13931da177e4SLinus Torvalds return csum; 13941da177e4SLinus Torvalds } 13951da177e4SLinus Torvalds 13961da177e4SLinus Torvalds void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) 13971da177e4SLinus Torvalds { 13981da177e4SLinus Torvalds unsigned int csum; 13991da177e4SLinus Torvalds long csstart; 14001da177e4SLinus Torvalds 140184fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) 14021da177e4SLinus Torvalds csstart = skb->h.raw - skb->data; 14031da177e4SLinus Torvalds else 14041da177e4SLinus Torvalds csstart = skb_headlen(skb); 14051da177e4SLinus Torvalds 140609a62660SKris Katterjohn BUG_ON(csstart > skb_headlen(skb)); 14071da177e4SLinus Torvalds 14081da177e4SLinus Torvalds memcpy(to, skb->data, csstart); 14091da177e4SLinus Torvalds 14101da177e4SLinus Torvalds csum = 0; 14111da177e4SLinus Torvalds if (csstart != skb->len) 14121da177e4SLinus Torvalds csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, 14131da177e4SLinus Torvalds skb->len - csstart, 0); 14141da177e4SLinus Torvalds 141584fa7933SPatrick McHardy if (skb->ip_summed == CHECKSUM_PARTIAL) { 14161da177e4SLinus Torvalds long csstuff = csstart + skb->csum; 14171da177e4SLinus Torvalds 14181da177e4SLinus Torvalds *((unsigned short *)(to + csstuff)) = csum_fold(csum); 14191da177e4SLinus Torvalds } 14201da177e4SLinus Torvalds } 14211da177e4SLinus Torvalds 14221da177e4SLinus Torvalds /** 14231da177e4SLinus Torvalds * skb_dequeue - remove from the head of the queue 14241da177e4SLinus Torvalds * @list: list to dequeue from 14251da177e4SLinus Torvalds * 14261da177e4SLinus Torvalds * Remove the head of the list. The list lock is taken so the function 14271da177e4SLinus Torvalds * may be used safely with other locking list functions. The head item is 14281da177e4SLinus Torvalds * returned or %NULL if the list is empty. 14291da177e4SLinus Torvalds */ 14301da177e4SLinus Torvalds 14311da177e4SLinus Torvalds struct sk_buff *skb_dequeue(struct sk_buff_head *list) 14321da177e4SLinus Torvalds { 14331da177e4SLinus Torvalds unsigned long flags; 14341da177e4SLinus Torvalds struct sk_buff *result; 14351da177e4SLinus Torvalds 14361da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 14371da177e4SLinus Torvalds result = __skb_dequeue(list); 14381da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 14391da177e4SLinus Torvalds return result; 14401da177e4SLinus Torvalds } 14411da177e4SLinus Torvalds 14421da177e4SLinus Torvalds /** 14431da177e4SLinus Torvalds * skb_dequeue_tail - remove from the tail of the queue 14441da177e4SLinus Torvalds * @list: list to dequeue from 14451da177e4SLinus Torvalds * 14461da177e4SLinus Torvalds * Remove the tail of the list. The list lock is taken so the function 14471da177e4SLinus Torvalds * may be used safely with other locking list functions. The tail item is 14481da177e4SLinus Torvalds * returned or %NULL if the list is empty. 14491da177e4SLinus Torvalds */ 14501da177e4SLinus Torvalds struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) 14511da177e4SLinus Torvalds { 14521da177e4SLinus Torvalds unsigned long flags; 14531da177e4SLinus Torvalds struct sk_buff *result; 14541da177e4SLinus Torvalds 14551da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 14561da177e4SLinus Torvalds result = __skb_dequeue_tail(list); 14571da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 14581da177e4SLinus Torvalds return result; 14591da177e4SLinus Torvalds } 14601da177e4SLinus Torvalds 14611da177e4SLinus Torvalds /** 14621da177e4SLinus Torvalds * skb_queue_purge - empty a list 14631da177e4SLinus Torvalds * @list: list to empty 14641da177e4SLinus Torvalds * 14651da177e4SLinus Torvalds * Delete all buffers on an &sk_buff list. Each buffer is removed from 14661da177e4SLinus Torvalds * the list and one reference dropped. This function takes the list 14671da177e4SLinus Torvalds * lock and is atomic with respect to other list locking functions. 14681da177e4SLinus Torvalds */ 14691da177e4SLinus Torvalds void skb_queue_purge(struct sk_buff_head *list) 14701da177e4SLinus Torvalds { 14711da177e4SLinus Torvalds struct sk_buff *skb; 14721da177e4SLinus Torvalds while ((skb = skb_dequeue(list)) != NULL) 14731da177e4SLinus Torvalds kfree_skb(skb); 14741da177e4SLinus Torvalds } 14751da177e4SLinus Torvalds 14761da177e4SLinus Torvalds /** 14771da177e4SLinus Torvalds * skb_queue_head - queue a buffer at the list head 14781da177e4SLinus Torvalds * @list: list to use 14791da177e4SLinus Torvalds * @newsk: buffer to queue 14801da177e4SLinus Torvalds * 14811da177e4SLinus Torvalds * Queue a buffer at the start of the list. This function takes the 14821da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 14831da177e4SLinus Torvalds * safely. 14841da177e4SLinus Torvalds * 14851da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 14861da177e4SLinus Torvalds */ 14871da177e4SLinus Torvalds void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) 14881da177e4SLinus Torvalds { 14891da177e4SLinus Torvalds unsigned long flags; 14901da177e4SLinus Torvalds 14911da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 14921da177e4SLinus Torvalds __skb_queue_head(list, newsk); 14931da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 14941da177e4SLinus Torvalds } 14951da177e4SLinus Torvalds 14961da177e4SLinus Torvalds /** 14971da177e4SLinus Torvalds * skb_queue_tail - queue a buffer at the list tail 14981da177e4SLinus Torvalds * @list: list to use 14991da177e4SLinus Torvalds * @newsk: buffer to queue 15001da177e4SLinus Torvalds * 15011da177e4SLinus Torvalds * Queue a buffer at the tail of the list. This function takes the 15021da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 15031da177e4SLinus Torvalds * safely. 15041da177e4SLinus Torvalds * 15051da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 15061da177e4SLinus Torvalds */ 15071da177e4SLinus Torvalds void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) 15081da177e4SLinus Torvalds { 15091da177e4SLinus Torvalds unsigned long flags; 15101da177e4SLinus Torvalds 15111da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 15121da177e4SLinus Torvalds __skb_queue_tail(list, newsk); 15131da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 15141da177e4SLinus Torvalds } 15158728b834SDavid S. Miller 15161da177e4SLinus Torvalds /** 15171da177e4SLinus Torvalds * skb_unlink - remove a buffer from a list 15181da177e4SLinus Torvalds * @skb: buffer to remove 15198728b834SDavid S. Miller * @list: list to use 15201da177e4SLinus Torvalds * 15218728b834SDavid S. Miller * Remove a packet from a list. The list locks are taken and this 15228728b834SDavid S. Miller * function is atomic with respect to other list locked calls 15231da177e4SLinus Torvalds * 15248728b834SDavid S. Miller * You must know what list the SKB is on. 15251da177e4SLinus Torvalds */ 15268728b834SDavid S. Miller void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 15271da177e4SLinus Torvalds { 15281da177e4SLinus Torvalds unsigned long flags; 15291da177e4SLinus Torvalds 15301da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 15318728b834SDavid S. Miller __skb_unlink(skb, list); 15321da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 15331da177e4SLinus Torvalds } 15341da177e4SLinus Torvalds 15351da177e4SLinus Torvalds /** 15361da177e4SLinus Torvalds * skb_append - append a buffer 15371da177e4SLinus Torvalds * @old: buffer to insert after 15381da177e4SLinus Torvalds * @newsk: buffer to insert 15398728b834SDavid S. Miller * @list: list to use 15401da177e4SLinus Torvalds * 15411da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 15421da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls. 15431da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 15441da177e4SLinus Torvalds */ 15458728b834SDavid S. Miller void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 15461da177e4SLinus Torvalds { 15471da177e4SLinus Torvalds unsigned long flags; 15481da177e4SLinus Torvalds 15498728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 15508728b834SDavid S. Miller __skb_append(old, newsk, list); 15518728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 15521da177e4SLinus Torvalds } 15531da177e4SLinus Torvalds 15541da177e4SLinus Torvalds 15551da177e4SLinus Torvalds /** 15561da177e4SLinus Torvalds * skb_insert - insert a buffer 15571da177e4SLinus Torvalds * @old: buffer to insert before 15581da177e4SLinus Torvalds * @newsk: buffer to insert 15598728b834SDavid S. Miller * @list: list to use 15601da177e4SLinus Torvalds * 15618728b834SDavid S. Miller * Place a packet before a given packet in a list. The list locks are 15628728b834SDavid S. Miller * taken and this function is atomic with respect to other list locked 15638728b834SDavid S. Miller * calls. 15648728b834SDavid S. Miller * 15651da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 15661da177e4SLinus Torvalds */ 15678728b834SDavid S. Miller void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 15681da177e4SLinus Torvalds { 15691da177e4SLinus Torvalds unsigned long flags; 15701da177e4SLinus Torvalds 15718728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 15728728b834SDavid S. Miller __skb_insert(newsk, old->prev, old, list); 15738728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 15741da177e4SLinus Torvalds } 15751da177e4SLinus Torvalds 15761da177e4SLinus Torvalds #if 0 15771da177e4SLinus Torvalds /* 15781da177e4SLinus Torvalds * Tune the memory allocator for a new MTU size. 15791da177e4SLinus Torvalds */ 15801da177e4SLinus Torvalds void skb_add_mtu(int mtu) 15811da177e4SLinus Torvalds { 15821da177e4SLinus Torvalds /* Must match allocation in alloc_skb */ 15831da177e4SLinus Torvalds mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info); 15841da177e4SLinus Torvalds 15851da177e4SLinus Torvalds kmem_add_cache_size(mtu); 15861da177e4SLinus Torvalds } 15871da177e4SLinus Torvalds #endif 15881da177e4SLinus Torvalds 15891da177e4SLinus Torvalds static inline void skb_split_inside_header(struct sk_buff *skb, 15901da177e4SLinus Torvalds struct sk_buff* skb1, 15911da177e4SLinus Torvalds const u32 len, const int pos) 15921da177e4SLinus Torvalds { 15931da177e4SLinus Torvalds int i; 15941da177e4SLinus Torvalds 15951da177e4SLinus Torvalds memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len); 15961da177e4SLinus Torvalds 15971da177e4SLinus Torvalds /* And move data appendix as is. */ 15981da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 15991da177e4SLinus Torvalds skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; 16001da177e4SLinus Torvalds 16011da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; 16021da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 16031da177e4SLinus Torvalds skb1->data_len = skb->data_len; 16041da177e4SLinus Torvalds skb1->len += skb1->data_len; 16051da177e4SLinus Torvalds skb->data_len = 0; 16061da177e4SLinus Torvalds skb->len = len; 16071da177e4SLinus Torvalds skb->tail = skb->data + len; 16081da177e4SLinus Torvalds } 16091da177e4SLinus Torvalds 16101da177e4SLinus Torvalds static inline void skb_split_no_header(struct sk_buff *skb, 16111da177e4SLinus Torvalds struct sk_buff* skb1, 16121da177e4SLinus Torvalds const u32 len, int pos) 16131da177e4SLinus Torvalds { 16141da177e4SLinus Torvalds int i, k = 0; 16151da177e4SLinus Torvalds const int nfrags = skb_shinfo(skb)->nr_frags; 16161da177e4SLinus Torvalds 16171da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 16181da177e4SLinus Torvalds skb1->len = skb1->data_len = skb->len - len; 16191da177e4SLinus Torvalds skb->len = len; 16201da177e4SLinus Torvalds skb->data_len = len - pos; 16211da177e4SLinus Torvalds 16221da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 16231da177e4SLinus Torvalds int size = skb_shinfo(skb)->frags[i].size; 16241da177e4SLinus Torvalds 16251da177e4SLinus Torvalds if (pos + size > len) { 16261da177e4SLinus Torvalds skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; 16271da177e4SLinus Torvalds 16281da177e4SLinus Torvalds if (pos < len) { 16291da177e4SLinus Torvalds /* Split frag. 16301da177e4SLinus Torvalds * We have two variants in this case: 16311da177e4SLinus Torvalds * 1. Move all the frag to the second 16321da177e4SLinus Torvalds * part, if it is possible. F.e. 16331da177e4SLinus Torvalds * this approach is mandatory for TUX, 16341da177e4SLinus Torvalds * where splitting is expensive. 16351da177e4SLinus Torvalds * 2. Split is accurately. We make this. 16361da177e4SLinus Torvalds */ 16371da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 16381da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].page_offset += len - pos; 16391da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].size -= len - pos; 16401da177e4SLinus Torvalds skb_shinfo(skb)->frags[i].size = len - pos; 16411da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 16421da177e4SLinus Torvalds } 16431da177e4SLinus Torvalds k++; 16441da177e4SLinus Torvalds } else 16451da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 16461da177e4SLinus Torvalds pos += size; 16471da177e4SLinus Torvalds } 16481da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = k; 16491da177e4SLinus Torvalds } 16501da177e4SLinus Torvalds 16511da177e4SLinus Torvalds /** 16521da177e4SLinus Torvalds * skb_split - Split fragmented skb to two parts at length len. 16531da177e4SLinus Torvalds * @skb: the buffer to split 16541da177e4SLinus Torvalds * @skb1: the buffer to receive the second part 16551da177e4SLinus Torvalds * @len: new length for skb 16561da177e4SLinus Torvalds */ 16571da177e4SLinus Torvalds void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) 16581da177e4SLinus Torvalds { 16591da177e4SLinus Torvalds int pos = skb_headlen(skb); 16601da177e4SLinus Torvalds 16611da177e4SLinus Torvalds if (len < pos) /* Split line is inside header. */ 16621da177e4SLinus Torvalds skb_split_inside_header(skb, skb1, len, pos); 16631da177e4SLinus Torvalds else /* Second chunk has no header, nothing to copy. */ 16641da177e4SLinus Torvalds skb_split_no_header(skb, skb1, len, pos); 16651da177e4SLinus Torvalds } 16661da177e4SLinus Torvalds 1667677e90edSThomas Graf /** 1668677e90edSThomas Graf * skb_prepare_seq_read - Prepare a sequential read of skb data 1669677e90edSThomas Graf * @skb: the buffer to read 1670677e90edSThomas Graf * @from: lower offset of data to be read 1671677e90edSThomas Graf * @to: upper offset of data to be read 1672677e90edSThomas Graf * @st: state variable 1673677e90edSThomas Graf * 1674677e90edSThomas Graf * Initializes the specified state variable. Must be called before 1675677e90edSThomas Graf * invoking skb_seq_read() for the first time. 1676677e90edSThomas Graf */ 1677677e90edSThomas Graf void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 1678677e90edSThomas Graf unsigned int to, struct skb_seq_state *st) 1679677e90edSThomas Graf { 1680677e90edSThomas Graf st->lower_offset = from; 1681677e90edSThomas Graf st->upper_offset = to; 1682677e90edSThomas Graf st->root_skb = st->cur_skb = skb; 1683677e90edSThomas Graf st->frag_idx = st->stepped_offset = 0; 1684677e90edSThomas Graf st->frag_data = NULL; 1685677e90edSThomas Graf } 1686677e90edSThomas Graf 1687677e90edSThomas Graf /** 1688677e90edSThomas Graf * skb_seq_read - Sequentially read skb data 1689677e90edSThomas Graf * @consumed: number of bytes consumed by the caller so far 1690677e90edSThomas Graf * @data: destination pointer for data to be returned 1691677e90edSThomas Graf * @st: state variable 1692677e90edSThomas Graf * 1693677e90edSThomas Graf * Reads a block of skb data at &consumed relative to the 1694677e90edSThomas Graf * lower offset specified to skb_prepare_seq_read(). Assigns 1695677e90edSThomas Graf * the head of the data block to &data and returns the length 1696677e90edSThomas Graf * of the block or 0 if the end of the skb data or the upper 1697677e90edSThomas Graf * offset has been reached. 1698677e90edSThomas Graf * 1699677e90edSThomas Graf * The caller is not required to consume all of the data 1700677e90edSThomas Graf * returned, i.e. &consumed is typically set to the number 1701677e90edSThomas Graf * of bytes already consumed and the next call to 1702677e90edSThomas Graf * skb_seq_read() will return the remaining part of the block. 1703677e90edSThomas Graf * 1704677e90edSThomas Graf * Note: The size of each block of data returned can be arbitary, 1705677e90edSThomas Graf * this limitation is the cost for zerocopy seqeuental 1706677e90edSThomas Graf * reads of potentially non linear data. 1707677e90edSThomas Graf * 1708677e90edSThomas Graf * Note: Fragment lists within fragments are not implemented 1709677e90edSThomas Graf * at the moment, state->root_skb could be replaced with 1710677e90edSThomas Graf * a stack for this purpose. 1711677e90edSThomas Graf */ 1712677e90edSThomas Graf unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 1713677e90edSThomas Graf struct skb_seq_state *st) 1714677e90edSThomas Graf { 1715677e90edSThomas Graf unsigned int block_limit, abs_offset = consumed + st->lower_offset; 1716677e90edSThomas Graf skb_frag_t *frag; 1717677e90edSThomas Graf 1718677e90edSThomas Graf if (unlikely(abs_offset >= st->upper_offset)) 1719677e90edSThomas Graf return 0; 1720677e90edSThomas Graf 1721677e90edSThomas Graf next_skb: 1722677e90edSThomas Graf block_limit = skb_headlen(st->cur_skb); 1723677e90edSThomas Graf 1724677e90edSThomas Graf if (abs_offset < block_limit) { 1725677e90edSThomas Graf *data = st->cur_skb->data + abs_offset; 1726677e90edSThomas Graf return block_limit - abs_offset; 1727677e90edSThomas Graf } 1728677e90edSThomas Graf 1729677e90edSThomas Graf if (st->frag_idx == 0 && !st->frag_data) 1730677e90edSThomas Graf st->stepped_offset += skb_headlen(st->cur_skb); 1731677e90edSThomas Graf 1732677e90edSThomas Graf while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { 1733677e90edSThomas Graf frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; 1734677e90edSThomas Graf block_limit = frag->size + st->stepped_offset; 1735677e90edSThomas Graf 1736677e90edSThomas Graf if (abs_offset < block_limit) { 1737677e90edSThomas Graf if (!st->frag_data) 1738677e90edSThomas Graf st->frag_data = kmap_skb_frag(frag); 1739677e90edSThomas Graf 1740677e90edSThomas Graf *data = (u8 *) st->frag_data + frag->page_offset + 1741677e90edSThomas Graf (abs_offset - st->stepped_offset); 1742677e90edSThomas Graf 1743677e90edSThomas Graf return block_limit - abs_offset; 1744677e90edSThomas Graf } 1745677e90edSThomas Graf 1746677e90edSThomas Graf if (st->frag_data) { 1747677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 1748677e90edSThomas Graf st->frag_data = NULL; 1749677e90edSThomas Graf } 1750677e90edSThomas Graf 1751677e90edSThomas Graf st->frag_idx++; 1752677e90edSThomas Graf st->stepped_offset += frag->size; 1753677e90edSThomas Graf } 1754677e90edSThomas Graf 1755677e90edSThomas Graf if (st->cur_skb->next) { 1756677e90edSThomas Graf st->cur_skb = st->cur_skb->next; 1757677e90edSThomas Graf st->frag_idx = 0; 1758677e90edSThomas Graf goto next_skb; 1759677e90edSThomas Graf } else if (st->root_skb == st->cur_skb && 1760677e90edSThomas Graf skb_shinfo(st->root_skb)->frag_list) { 1761677e90edSThomas Graf st->cur_skb = skb_shinfo(st->root_skb)->frag_list; 1762677e90edSThomas Graf goto next_skb; 1763677e90edSThomas Graf } 1764677e90edSThomas Graf 1765677e90edSThomas Graf return 0; 1766677e90edSThomas Graf } 1767677e90edSThomas Graf 1768677e90edSThomas Graf /** 1769677e90edSThomas Graf * skb_abort_seq_read - Abort a sequential read of skb data 1770677e90edSThomas Graf * @st: state variable 1771677e90edSThomas Graf * 1772677e90edSThomas Graf * Must be called if skb_seq_read() was not called until it 1773677e90edSThomas Graf * returned 0. 1774677e90edSThomas Graf */ 1775677e90edSThomas Graf void skb_abort_seq_read(struct skb_seq_state *st) 1776677e90edSThomas Graf { 1777677e90edSThomas Graf if (st->frag_data) 1778677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 1779677e90edSThomas Graf } 1780677e90edSThomas Graf 17813fc7e8a6SThomas Graf #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) 17823fc7e8a6SThomas Graf 17833fc7e8a6SThomas Graf static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, 17843fc7e8a6SThomas Graf struct ts_config *conf, 17853fc7e8a6SThomas Graf struct ts_state *state) 17863fc7e8a6SThomas Graf { 17873fc7e8a6SThomas Graf return skb_seq_read(offset, text, TS_SKB_CB(state)); 17883fc7e8a6SThomas Graf } 17893fc7e8a6SThomas Graf 17903fc7e8a6SThomas Graf static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) 17913fc7e8a6SThomas Graf { 17923fc7e8a6SThomas Graf skb_abort_seq_read(TS_SKB_CB(state)); 17933fc7e8a6SThomas Graf } 17943fc7e8a6SThomas Graf 17953fc7e8a6SThomas Graf /** 17963fc7e8a6SThomas Graf * skb_find_text - Find a text pattern in skb data 17973fc7e8a6SThomas Graf * @skb: the buffer to look in 17983fc7e8a6SThomas Graf * @from: search offset 17993fc7e8a6SThomas Graf * @to: search limit 18003fc7e8a6SThomas Graf * @config: textsearch configuration 18013fc7e8a6SThomas Graf * @state: uninitialized textsearch state variable 18023fc7e8a6SThomas Graf * 18033fc7e8a6SThomas Graf * Finds a pattern in the skb data according to the specified 18043fc7e8a6SThomas Graf * textsearch configuration. Use textsearch_next() to retrieve 18053fc7e8a6SThomas Graf * subsequent occurrences of the pattern. Returns the offset 18063fc7e8a6SThomas Graf * to the first occurrence or UINT_MAX if no match was found. 18073fc7e8a6SThomas Graf */ 18083fc7e8a6SThomas Graf unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 18093fc7e8a6SThomas Graf unsigned int to, struct ts_config *config, 18103fc7e8a6SThomas Graf struct ts_state *state) 18113fc7e8a6SThomas Graf { 1812f72b948dSPhil Oester unsigned int ret; 1813f72b948dSPhil Oester 18143fc7e8a6SThomas Graf config->get_next_block = skb_ts_get_next_block; 18153fc7e8a6SThomas Graf config->finish = skb_ts_finish; 18163fc7e8a6SThomas Graf 18173fc7e8a6SThomas Graf skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); 18183fc7e8a6SThomas Graf 1819f72b948dSPhil Oester ret = textsearch_find(config, state); 1820f72b948dSPhil Oester return (ret <= to - from ? ret : UINT_MAX); 18213fc7e8a6SThomas Graf } 18223fc7e8a6SThomas Graf 1823e89e9cf5SAnanda Raju /** 1824e89e9cf5SAnanda Raju * skb_append_datato_frags: - append the user data to a skb 1825e89e9cf5SAnanda Raju * @sk: sock structure 1826e89e9cf5SAnanda Raju * @skb: skb structure to be appened with user data. 1827e89e9cf5SAnanda Raju * @getfrag: call back function to be used for getting the user data 1828e89e9cf5SAnanda Raju * @from: pointer to user message iov 1829e89e9cf5SAnanda Raju * @length: length of the iov message 1830e89e9cf5SAnanda Raju * 1831e89e9cf5SAnanda Raju * Description: This procedure append the user data in the fragment part 1832e89e9cf5SAnanda Raju * of the skb if any page alloc fails user this procedure returns -ENOMEM 1833e89e9cf5SAnanda Raju */ 1834e89e9cf5SAnanda Raju int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, 1835dab9630fSMartin Waitz int (*getfrag)(void *from, char *to, int offset, 1836e89e9cf5SAnanda Raju int len, int odd, struct sk_buff *skb), 1837e89e9cf5SAnanda Raju void *from, int length) 1838e89e9cf5SAnanda Raju { 1839e89e9cf5SAnanda Raju int frg_cnt = 0; 1840e89e9cf5SAnanda Raju skb_frag_t *frag = NULL; 1841e89e9cf5SAnanda Raju struct page *page = NULL; 1842e89e9cf5SAnanda Raju int copy, left; 1843e89e9cf5SAnanda Raju int offset = 0; 1844e89e9cf5SAnanda Raju int ret; 1845e89e9cf5SAnanda Raju 1846e89e9cf5SAnanda Raju do { 1847e89e9cf5SAnanda Raju /* Return error if we don't have space for new frag */ 1848e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 1849e89e9cf5SAnanda Raju if (frg_cnt >= MAX_SKB_FRAGS) 1850e89e9cf5SAnanda Raju return -EFAULT; 1851e89e9cf5SAnanda Raju 1852e89e9cf5SAnanda Raju /* allocate a new page for next frag */ 1853e89e9cf5SAnanda Raju page = alloc_pages(sk->sk_allocation, 0); 1854e89e9cf5SAnanda Raju 1855e89e9cf5SAnanda Raju /* If alloc_page fails just return failure and caller will 1856e89e9cf5SAnanda Raju * free previous allocated pages by doing kfree_skb() 1857e89e9cf5SAnanda Raju */ 1858e89e9cf5SAnanda Raju if (page == NULL) 1859e89e9cf5SAnanda Raju return -ENOMEM; 1860e89e9cf5SAnanda Raju 1861e89e9cf5SAnanda Raju /* initialize the next frag */ 1862e89e9cf5SAnanda Raju sk->sk_sndmsg_page = page; 1863e89e9cf5SAnanda Raju sk->sk_sndmsg_off = 0; 1864e89e9cf5SAnanda Raju skb_fill_page_desc(skb, frg_cnt, page, 0, 0); 1865e89e9cf5SAnanda Raju skb->truesize += PAGE_SIZE; 1866e89e9cf5SAnanda Raju atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1867e89e9cf5SAnanda Raju 1868e89e9cf5SAnanda Raju /* get the new initialized frag */ 1869e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 1870e89e9cf5SAnanda Raju frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; 1871e89e9cf5SAnanda Raju 1872e89e9cf5SAnanda Raju /* copy the user data to page */ 1873e89e9cf5SAnanda Raju left = PAGE_SIZE - frag->page_offset; 1874e89e9cf5SAnanda Raju copy = (length > left)? left : length; 1875e89e9cf5SAnanda Raju 1876e89e9cf5SAnanda Raju ret = getfrag(from, (page_address(frag->page) + 1877e89e9cf5SAnanda Raju frag->page_offset + frag->size), 1878e89e9cf5SAnanda Raju offset, copy, 0, skb); 1879e89e9cf5SAnanda Raju if (ret < 0) 1880e89e9cf5SAnanda Raju return -EFAULT; 1881e89e9cf5SAnanda Raju 1882e89e9cf5SAnanda Raju /* copy was successful so update the size parameters */ 1883e89e9cf5SAnanda Raju sk->sk_sndmsg_off += copy; 1884e89e9cf5SAnanda Raju frag->size += copy; 1885e89e9cf5SAnanda Raju skb->len += copy; 1886e89e9cf5SAnanda Raju skb->data_len += copy; 1887e89e9cf5SAnanda Raju offset += copy; 1888e89e9cf5SAnanda Raju length -= copy; 1889e89e9cf5SAnanda Raju 1890e89e9cf5SAnanda Raju } while (length > 0); 1891e89e9cf5SAnanda Raju 1892e89e9cf5SAnanda Raju return 0; 1893e89e9cf5SAnanda Raju } 1894e89e9cf5SAnanda Raju 1895cbb042f9SHerbert Xu /** 1896cbb042f9SHerbert Xu * skb_pull_rcsum - pull skb and update receive checksum 1897cbb042f9SHerbert Xu * @skb: buffer to update 1898cbb042f9SHerbert Xu * @start: start of data before pull 1899cbb042f9SHerbert Xu * @len: length of data pulled 1900cbb042f9SHerbert Xu * 1901cbb042f9SHerbert Xu * This function performs an skb_pull on the packet and updates 190284fa7933SPatrick McHardy * update the CHECKSUM_COMPLETE checksum. It should be used on 190384fa7933SPatrick McHardy * receive path processing instead of skb_pull unless you know 190484fa7933SPatrick McHardy * that the checksum difference is zero (e.g., a valid IP header) 190584fa7933SPatrick McHardy * or you are setting ip_summed to CHECKSUM_NONE. 1906cbb042f9SHerbert Xu */ 1907cbb042f9SHerbert Xu unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) 1908cbb042f9SHerbert Xu { 1909cbb042f9SHerbert Xu BUG_ON(len > skb->len); 1910cbb042f9SHerbert Xu skb->len -= len; 1911cbb042f9SHerbert Xu BUG_ON(skb->len < skb->data_len); 1912cbb042f9SHerbert Xu skb_postpull_rcsum(skb, skb->data, len); 1913cbb042f9SHerbert Xu return skb->data += len; 1914cbb042f9SHerbert Xu } 1915cbb042f9SHerbert Xu 1916f94691acSArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(skb_pull_rcsum); 1917f94691acSArnaldo Carvalho de Melo 1918f4c50d99SHerbert Xu /** 1919f4c50d99SHerbert Xu * skb_segment - Perform protocol segmentation on skb. 1920f4c50d99SHerbert Xu * @skb: buffer to segment 1921576a30ebSHerbert Xu * @features: features for the output path (see dev->features) 1922f4c50d99SHerbert Xu * 1923f4c50d99SHerbert Xu * This function performs segmentation on the given skb. It returns 1924f4c50d99SHerbert Xu * the segment at the given position. It returns NULL if there are 1925f4c50d99SHerbert Xu * no more segments to generate, or when an error is encountered. 1926f4c50d99SHerbert Xu */ 1927576a30ebSHerbert Xu struct sk_buff *skb_segment(struct sk_buff *skb, int features) 1928f4c50d99SHerbert Xu { 1929f4c50d99SHerbert Xu struct sk_buff *segs = NULL; 1930f4c50d99SHerbert Xu struct sk_buff *tail = NULL; 1931f4c50d99SHerbert Xu unsigned int mss = skb_shinfo(skb)->gso_size; 1932f4c50d99SHerbert Xu unsigned int doffset = skb->data - skb->mac.raw; 1933f4c50d99SHerbert Xu unsigned int offset = doffset; 1934f4c50d99SHerbert Xu unsigned int headroom; 1935f4c50d99SHerbert Xu unsigned int len; 1936576a30ebSHerbert Xu int sg = features & NETIF_F_SG; 1937f4c50d99SHerbert Xu int nfrags = skb_shinfo(skb)->nr_frags; 1938f4c50d99SHerbert Xu int err = -ENOMEM; 1939f4c50d99SHerbert Xu int i = 0; 1940f4c50d99SHerbert Xu int pos; 1941f4c50d99SHerbert Xu 1942f4c50d99SHerbert Xu __skb_push(skb, doffset); 1943f4c50d99SHerbert Xu headroom = skb_headroom(skb); 1944f4c50d99SHerbert Xu pos = skb_headlen(skb); 1945f4c50d99SHerbert Xu 1946f4c50d99SHerbert Xu do { 1947f4c50d99SHerbert Xu struct sk_buff *nskb; 1948f4c50d99SHerbert Xu skb_frag_t *frag; 1949c8884eddSHerbert Xu int hsize; 1950f4c50d99SHerbert Xu int k; 1951f4c50d99SHerbert Xu int size; 1952f4c50d99SHerbert Xu 1953f4c50d99SHerbert Xu len = skb->len - offset; 1954f4c50d99SHerbert Xu if (len > mss) 1955f4c50d99SHerbert Xu len = mss; 1956f4c50d99SHerbert Xu 1957f4c50d99SHerbert Xu hsize = skb_headlen(skb) - offset; 1958f4c50d99SHerbert Xu if (hsize < 0) 1959f4c50d99SHerbert Xu hsize = 0; 1960c8884eddSHerbert Xu if (hsize > len || !sg) 1961c8884eddSHerbert Xu hsize = len; 1962f4c50d99SHerbert Xu 1963c8884eddSHerbert Xu nskb = alloc_skb(hsize + doffset + headroom, GFP_ATOMIC); 1964f4c50d99SHerbert Xu if (unlikely(!nskb)) 1965f4c50d99SHerbert Xu goto err; 1966f4c50d99SHerbert Xu 1967f4c50d99SHerbert Xu if (segs) 1968f4c50d99SHerbert Xu tail->next = nskb; 1969f4c50d99SHerbert Xu else 1970f4c50d99SHerbert Xu segs = nskb; 1971f4c50d99SHerbert Xu tail = nskb; 1972f4c50d99SHerbert Xu 1973f4c50d99SHerbert Xu nskb->dev = skb->dev; 1974f4c50d99SHerbert Xu nskb->priority = skb->priority; 1975f4c50d99SHerbert Xu nskb->protocol = skb->protocol; 1976f4c50d99SHerbert Xu nskb->dst = dst_clone(skb->dst); 1977f4c50d99SHerbert Xu memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); 1978f4c50d99SHerbert Xu nskb->pkt_type = skb->pkt_type; 1979f4c50d99SHerbert Xu nskb->mac_len = skb->mac_len; 1980f4c50d99SHerbert Xu 1981f4c50d99SHerbert Xu skb_reserve(nskb, headroom); 1982f4c50d99SHerbert Xu nskb->mac.raw = nskb->data; 1983f4c50d99SHerbert Xu nskb->nh.raw = nskb->data + skb->mac_len; 1984f4c50d99SHerbert Xu nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw); 1985f4c50d99SHerbert Xu memcpy(skb_put(nskb, doffset), skb->data, doffset); 1986f4c50d99SHerbert Xu 1987f4c50d99SHerbert Xu if (!sg) { 1988f4c50d99SHerbert Xu nskb->csum = skb_copy_and_csum_bits(skb, offset, 1989f4c50d99SHerbert Xu skb_put(nskb, len), 1990f4c50d99SHerbert Xu len, 0); 1991f4c50d99SHerbert Xu continue; 1992f4c50d99SHerbert Xu } 1993f4c50d99SHerbert Xu 1994f4c50d99SHerbert Xu frag = skb_shinfo(nskb)->frags; 1995f4c50d99SHerbert Xu k = 0; 1996f4c50d99SHerbert Xu 199784fa7933SPatrick McHardy nskb->ip_summed = CHECKSUM_PARTIAL; 1998f4c50d99SHerbert Xu nskb->csum = skb->csum; 1999f4c50d99SHerbert Xu memcpy(skb_put(nskb, hsize), skb->data + offset, hsize); 2000f4c50d99SHerbert Xu 2001f4c50d99SHerbert Xu while (pos < offset + len) { 2002f4c50d99SHerbert Xu BUG_ON(i >= nfrags); 2003f4c50d99SHerbert Xu 2004f4c50d99SHerbert Xu *frag = skb_shinfo(skb)->frags[i]; 2005f4c50d99SHerbert Xu get_page(frag->page); 2006f4c50d99SHerbert Xu size = frag->size; 2007f4c50d99SHerbert Xu 2008f4c50d99SHerbert Xu if (pos < offset) { 2009f4c50d99SHerbert Xu frag->page_offset += offset - pos; 2010f4c50d99SHerbert Xu frag->size -= offset - pos; 2011f4c50d99SHerbert Xu } 2012f4c50d99SHerbert Xu 2013f4c50d99SHerbert Xu k++; 2014f4c50d99SHerbert Xu 2015f4c50d99SHerbert Xu if (pos + size <= offset + len) { 2016f4c50d99SHerbert Xu i++; 2017f4c50d99SHerbert Xu pos += size; 2018f4c50d99SHerbert Xu } else { 2019f4c50d99SHerbert Xu frag->size -= pos + size - (offset + len); 2020f4c50d99SHerbert Xu break; 2021f4c50d99SHerbert Xu } 2022f4c50d99SHerbert Xu 2023f4c50d99SHerbert Xu frag++; 2024f4c50d99SHerbert Xu } 2025f4c50d99SHerbert Xu 2026f4c50d99SHerbert Xu skb_shinfo(nskb)->nr_frags = k; 2027f4c50d99SHerbert Xu nskb->data_len = len - hsize; 2028f4c50d99SHerbert Xu nskb->len += nskb->data_len; 2029f4c50d99SHerbert Xu nskb->truesize += nskb->data_len; 2030f4c50d99SHerbert Xu } while ((offset += len) < skb->len); 2031f4c50d99SHerbert Xu 2032f4c50d99SHerbert Xu return segs; 2033f4c50d99SHerbert Xu 2034f4c50d99SHerbert Xu err: 2035f4c50d99SHerbert Xu while ((skb = segs)) { 2036f4c50d99SHerbert Xu segs = skb->next; 2037f4c50d99SHerbert Xu kfree(skb); 2038f4c50d99SHerbert Xu } 2039f4c50d99SHerbert Xu return ERR_PTR(err); 2040f4c50d99SHerbert Xu } 2041f4c50d99SHerbert Xu 2042f4c50d99SHerbert Xu EXPORT_SYMBOL_GPL(skb_segment); 2043f4c50d99SHerbert Xu 20441da177e4SLinus Torvalds void __init skb_init(void) 20451da177e4SLinus Torvalds { 20461da177e4SLinus Torvalds skbuff_head_cache = kmem_cache_create("skbuff_head_cache", 20471da177e4SLinus Torvalds sizeof(struct sk_buff), 20481da177e4SLinus Torvalds 0, 2049e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 20501da177e4SLinus Torvalds NULL, NULL); 2051d179cd12SDavid S. Miller skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", 2052d179cd12SDavid S. Miller (2*sizeof(struct sk_buff)) + 2053d179cd12SDavid S. Miller sizeof(atomic_t), 2054d179cd12SDavid S. Miller 0, 2055e5d679f3SAlexey Dobriyan SLAB_HWCACHE_ALIGN|SLAB_PANIC, 2056d179cd12SDavid S. Miller NULL, NULL); 20571da177e4SLinus Torvalds } 20581da177e4SLinus Torvalds 20591da177e4SLinus Torvalds EXPORT_SYMBOL(___pskb_trim); 20601da177e4SLinus Torvalds EXPORT_SYMBOL(__kfree_skb); 2061231d06aeSJörn Engel EXPORT_SYMBOL(kfree_skb); 20621da177e4SLinus Torvalds EXPORT_SYMBOL(__pskb_pull_tail); 2063d179cd12SDavid S. Miller EXPORT_SYMBOL(__alloc_skb); 20648af27456SChristoph Hellwig EXPORT_SYMBOL(__netdev_alloc_skb); 20651da177e4SLinus Torvalds EXPORT_SYMBOL(pskb_copy); 20661da177e4SLinus Torvalds EXPORT_SYMBOL(pskb_expand_head); 20671da177e4SLinus Torvalds EXPORT_SYMBOL(skb_checksum); 20681da177e4SLinus Torvalds EXPORT_SYMBOL(skb_clone); 20691da177e4SLinus Torvalds EXPORT_SYMBOL(skb_clone_fraglist); 20701da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy); 20711da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_and_csum_bits); 20721da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_and_csum_dev); 20731da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_bits); 20741da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_expand); 20751da177e4SLinus Torvalds EXPORT_SYMBOL(skb_over_panic); 20761da177e4SLinus Torvalds EXPORT_SYMBOL(skb_pad); 20771da177e4SLinus Torvalds EXPORT_SYMBOL(skb_realloc_headroom); 20781da177e4SLinus Torvalds EXPORT_SYMBOL(skb_under_panic); 20791da177e4SLinus Torvalds EXPORT_SYMBOL(skb_dequeue); 20801da177e4SLinus Torvalds EXPORT_SYMBOL(skb_dequeue_tail); 20811da177e4SLinus Torvalds EXPORT_SYMBOL(skb_insert); 20821da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_purge); 20831da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_head); 20841da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_tail); 20851da177e4SLinus Torvalds EXPORT_SYMBOL(skb_unlink); 20861da177e4SLinus Torvalds EXPORT_SYMBOL(skb_append); 20871da177e4SLinus Torvalds EXPORT_SYMBOL(skb_split); 2088677e90edSThomas Graf EXPORT_SYMBOL(skb_prepare_seq_read); 2089677e90edSThomas Graf EXPORT_SYMBOL(skb_seq_read); 2090677e90edSThomas Graf EXPORT_SYMBOL(skb_abort_seq_read); 20913fc7e8a6SThomas Graf EXPORT_SYMBOL(skb_find_text); 2092e89e9cf5SAnanda Raju EXPORT_SYMBOL(skb_append_datato_frags); 2093