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/config.h> 421da177e4SLinus Torvalds #include <linux/module.h> 431da177e4SLinus Torvalds #include <linux/types.h> 441da177e4SLinus Torvalds #include <linux/kernel.h> 451da177e4SLinus Torvalds #include <linux/sched.h> 461da177e4SLinus Torvalds #include <linux/mm.h> 471da177e4SLinus Torvalds #include <linux/interrupt.h> 481da177e4SLinus Torvalds #include <linux/in.h> 491da177e4SLinus Torvalds #include <linux/inet.h> 501da177e4SLinus Torvalds #include <linux/slab.h> 511da177e4SLinus Torvalds #include <linux/netdevice.h> 521da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 531da177e4SLinus Torvalds #include <net/pkt_sched.h> 541da177e4SLinus Torvalds #endif 551da177e4SLinus Torvalds #include <linux/string.h> 561da177e4SLinus Torvalds #include <linux/skbuff.h> 571da177e4SLinus Torvalds #include <linux/cache.h> 581da177e4SLinus Torvalds #include <linux/rtnetlink.h> 591da177e4SLinus Torvalds #include <linux/init.h> 601da177e4SLinus Torvalds #include <linux/highmem.h> 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds #include <net/protocol.h> 631da177e4SLinus Torvalds #include <net/dst.h> 641da177e4SLinus Torvalds #include <net/sock.h> 651da177e4SLinus Torvalds #include <net/checksum.h> 661da177e4SLinus Torvalds #include <net/xfrm.h> 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds #include <asm/uaccess.h> 691da177e4SLinus Torvalds #include <asm/system.h> 701da177e4SLinus Torvalds 71ba89966cSEric Dumazet static kmem_cache_t *skbuff_head_cache __read_mostly; 72ba89966cSEric Dumazet static kmem_cache_t *skbuff_fclone_cache __read_mostly; 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds /* 751da177e4SLinus Torvalds * Keep out-of-line to prevent kernel bloat. 761da177e4SLinus Torvalds * __builtin_return_address is not used because it is not always 771da177e4SLinus Torvalds * reliable. 781da177e4SLinus Torvalds */ 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds /** 811da177e4SLinus Torvalds * skb_over_panic - private function 821da177e4SLinus Torvalds * @skb: buffer 831da177e4SLinus Torvalds * @sz: size 841da177e4SLinus Torvalds * @here: address 851da177e4SLinus Torvalds * 861da177e4SLinus Torvalds * Out of line support code for skb_put(). Not user callable. 871da177e4SLinus Torvalds */ 881da177e4SLinus Torvalds void skb_over_panic(struct sk_buff *skb, int sz, void *here) 891da177e4SLinus Torvalds { 9026095455SPatrick McHardy printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " 9126095455SPatrick McHardy "data:%p tail:%p end:%p dev:%s\n", 9226095455SPatrick McHardy here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, 9326095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 941da177e4SLinus Torvalds BUG(); 951da177e4SLinus Torvalds } 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds /** 981da177e4SLinus Torvalds * skb_under_panic - private function 991da177e4SLinus Torvalds * @skb: buffer 1001da177e4SLinus Torvalds * @sz: size 1011da177e4SLinus Torvalds * @here: address 1021da177e4SLinus Torvalds * 1031da177e4SLinus Torvalds * Out of line support code for skb_push(). Not user callable. 1041da177e4SLinus Torvalds */ 1051da177e4SLinus Torvalds 1061da177e4SLinus Torvalds void skb_under_panic(struct sk_buff *skb, int sz, void *here) 1071da177e4SLinus Torvalds { 10826095455SPatrick McHardy printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " 10926095455SPatrick McHardy "data:%p tail:%p end:%p dev:%s\n", 11026095455SPatrick McHardy here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, 11126095455SPatrick McHardy skb->dev ? skb->dev->name : "<NULL>"); 1121da177e4SLinus Torvalds BUG(); 1131da177e4SLinus Torvalds } 1141da177e4SLinus Torvalds 115dc6de336SDavid S. Miller void skb_truesize_bug(struct sk_buff *skb) 116dc6de336SDavid S. Miller { 117dc6de336SDavid S. Miller printk(KERN_ERR "SKB BUG: Invalid truesize (%u) " 118dc6de336SDavid S. Miller "len=%u, sizeof(sk_buff)=%Zd\n", 119dc6de336SDavid S. Miller skb->truesize, skb->len, sizeof(struct sk_buff)); 120dc6de336SDavid S. Miller } 121dc6de336SDavid S. Miller EXPORT_SYMBOL(skb_truesize_bug); 122dc6de336SDavid S. Miller 1231da177e4SLinus Torvalds /* Allocate a new skbuff. We do this ourselves so we can fill in a few 1241da177e4SLinus Torvalds * 'private' fields and also do memory statistics to find all the 1251da177e4SLinus Torvalds * [BEEP] leaks. 1261da177e4SLinus Torvalds * 1271da177e4SLinus Torvalds */ 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds /** 130d179cd12SDavid S. Miller * __alloc_skb - allocate a network buffer 1311da177e4SLinus Torvalds * @size: size to allocate 1321da177e4SLinus Torvalds * @gfp_mask: allocation mask 133c83c2486SRandy Dunlap * @fclone: allocate from fclone cache instead of head cache 134c83c2486SRandy Dunlap * and allocate a cloned (child) skb 1351da177e4SLinus Torvalds * 1361da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and a 1371da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 1381da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 1391da177e4SLinus Torvalds * 1401da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1411da177e4SLinus Torvalds * %GFP_ATOMIC. 1421da177e4SLinus Torvalds */ 143dd0fc66fSAl Viro struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, 144d179cd12SDavid S. Miller int fclone) 1451da177e4SLinus Torvalds { 1468798b3fbSHerbert Xu kmem_cache_t *cache; 1474947d3efSBenjamin LaHaise struct skb_shared_info *shinfo; 1481da177e4SLinus Torvalds struct sk_buff *skb; 1491da177e4SLinus Torvalds u8 *data; 1501da177e4SLinus Torvalds 1518798b3fbSHerbert Xu cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; 1528798b3fbSHerbert Xu 1531da177e4SLinus Torvalds /* Get the HEAD */ 1548798b3fbSHerbert Xu skb = kmem_cache_alloc(cache, gfp_mask & ~__GFP_DMA); 1551da177e4SLinus Torvalds if (!skb) 1561da177e4SLinus Torvalds goto out; 1571da177e4SLinus Torvalds 1581da177e4SLinus Torvalds /* Get the DATA. Size must match skb_add_mtu(). */ 1591da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 160871751e2SAl Viro data = ____kmalloc(size + sizeof(struct skb_shared_info), 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; 1754947d3efSBenjamin LaHaise shinfo->tso_size = 0; 1764947d3efSBenjamin LaHaise shinfo->tso_segs = 0; 1774947d3efSBenjamin LaHaise shinfo->ufo_size = 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; 2411da177e4SLinus Torvalds skb_shinfo(skb)->tso_size = 0; 2421da177e4SLinus Torvalds skb_shinfo(skb)->tso_segs = 0; 2431da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = NULL; 2441da177e4SLinus Torvalds out: 2451da177e4SLinus Torvalds return skb; 2461da177e4SLinus Torvalds nodata: 2471da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 2481da177e4SLinus Torvalds skb = NULL; 2491da177e4SLinus Torvalds goto out; 2501da177e4SLinus Torvalds } 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds 2531da177e4SLinus Torvalds static void skb_drop_fraglist(struct sk_buff *skb) 2541da177e4SLinus Torvalds { 2551da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 2561da177e4SLinus Torvalds 2571da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = NULL; 2581da177e4SLinus Torvalds 2591da177e4SLinus Torvalds do { 2601da177e4SLinus Torvalds struct sk_buff *this = list; 2611da177e4SLinus Torvalds list = list->next; 2621da177e4SLinus Torvalds kfree_skb(this); 2631da177e4SLinus Torvalds } while (list); 2641da177e4SLinus Torvalds } 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds static void skb_clone_fraglist(struct sk_buff *skb) 2671da177e4SLinus Torvalds { 2681da177e4SLinus Torvalds struct sk_buff *list; 2691da177e4SLinus Torvalds 2701da177e4SLinus Torvalds for (list = skb_shinfo(skb)->frag_list; list; list = list->next) 2711da177e4SLinus Torvalds skb_get(list); 2721da177e4SLinus Torvalds } 2731da177e4SLinus Torvalds 2741da177e4SLinus Torvalds void skb_release_data(struct sk_buff *skb) 2751da177e4SLinus Torvalds { 2761da177e4SLinus Torvalds if (!skb->cloned || 2771da177e4SLinus Torvalds !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, 2781da177e4SLinus Torvalds &skb_shinfo(skb)->dataref)) { 2791da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 2801da177e4SLinus Torvalds int i; 2811da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 2821da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 2831da177e4SLinus Torvalds } 2841da177e4SLinus Torvalds 2851da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 2861da177e4SLinus Torvalds skb_drop_fraglist(skb); 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds kfree(skb->head); 2891da177e4SLinus Torvalds } 2901da177e4SLinus Torvalds } 2911da177e4SLinus Torvalds 2921da177e4SLinus Torvalds /* 2931da177e4SLinus Torvalds * Free an skbuff by memory without cleaning the state. 2941da177e4SLinus Torvalds */ 2951da177e4SLinus Torvalds void kfree_skbmem(struct sk_buff *skb) 2961da177e4SLinus Torvalds { 297d179cd12SDavid S. Miller struct sk_buff *other; 298d179cd12SDavid S. Miller atomic_t *fclone_ref; 299d179cd12SDavid S. Miller 3001da177e4SLinus Torvalds skb_release_data(skb); 301d179cd12SDavid S. Miller switch (skb->fclone) { 302d179cd12SDavid S. Miller case SKB_FCLONE_UNAVAILABLE: 3031da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 304d179cd12SDavid S. Miller break; 305d179cd12SDavid S. Miller 306d179cd12SDavid S. Miller case SKB_FCLONE_ORIG: 307d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 2); 308d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 309d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, skb); 310d179cd12SDavid S. Miller break; 311d179cd12SDavid S. Miller 312d179cd12SDavid S. Miller case SKB_FCLONE_CLONE: 313d179cd12SDavid S. Miller fclone_ref = (atomic_t *) (skb + 1); 314d179cd12SDavid S. Miller other = skb - 1; 315d179cd12SDavid S. Miller 316d179cd12SDavid S. Miller /* The clone portion is available for 317d179cd12SDavid S. Miller * fast-cloning again. 318d179cd12SDavid S. Miller */ 319d179cd12SDavid S. Miller skb->fclone = SKB_FCLONE_UNAVAILABLE; 320d179cd12SDavid S. Miller 321d179cd12SDavid S. Miller if (atomic_dec_and_test(fclone_ref)) 322d179cd12SDavid S. Miller kmem_cache_free(skbuff_fclone_cache, other); 323d179cd12SDavid S. Miller break; 324d179cd12SDavid S. Miller }; 3251da177e4SLinus Torvalds } 3261da177e4SLinus Torvalds 3271da177e4SLinus Torvalds /** 3281da177e4SLinus Torvalds * __kfree_skb - private function 3291da177e4SLinus Torvalds * @skb: buffer 3301da177e4SLinus Torvalds * 3311da177e4SLinus Torvalds * Free an sk_buff. Release anything attached to the buffer. 3321da177e4SLinus Torvalds * Clean the state. This is an internal helper function. Users should 3331da177e4SLinus Torvalds * always call kfree_skb 3341da177e4SLinus Torvalds */ 3351da177e4SLinus Torvalds 3361da177e4SLinus Torvalds void __kfree_skb(struct sk_buff *skb) 3371da177e4SLinus Torvalds { 3381da177e4SLinus Torvalds dst_release(skb->dst); 3391da177e4SLinus Torvalds #ifdef CONFIG_XFRM 3401da177e4SLinus Torvalds secpath_put(skb->sp); 3411da177e4SLinus Torvalds #endif 3421da177e4SLinus Torvalds if (skb->destructor) { 3439c2b3328SStephen Hemminger WARN_ON(in_irq()); 3441da177e4SLinus Torvalds skb->destructor(skb); 3451da177e4SLinus Torvalds } 3461da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 3471da177e4SLinus Torvalds nf_conntrack_put(skb->nfct); 3489fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 3499fb9cbb1SYasuyuki Kozakai nf_conntrack_put_reasm(skb->nfct_reasm); 3509fb9cbb1SYasuyuki Kozakai #endif 3511da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 3521da177e4SLinus Torvalds nf_bridge_put(skb->nf_bridge); 3531da177e4SLinus Torvalds #endif 3541da177e4SLinus Torvalds #endif 3551da177e4SLinus Torvalds /* XXX: IS this still necessary? - JHS */ 3561da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 3571da177e4SLinus Torvalds skb->tc_index = 0; 3581da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 3591da177e4SLinus Torvalds skb->tc_verd = 0; 3601da177e4SLinus Torvalds #endif 3611da177e4SLinus Torvalds #endif 3621da177e4SLinus Torvalds 3631da177e4SLinus Torvalds kfree_skbmem(skb); 3641da177e4SLinus Torvalds } 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds /** 367231d06aeSJörn Engel * kfree_skb - free an sk_buff 368231d06aeSJörn Engel * @skb: buffer to free 369231d06aeSJörn Engel * 370231d06aeSJörn Engel * Drop a reference to the buffer and free it if the usage count has 371231d06aeSJörn Engel * hit zero. 372231d06aeSJörn Engel */ 373231d06aeSJörn Engel void kfree_skb(struct sk_buff *skb) 374231d06aeSJörn Engel { 375231d06aeSJörn Engel if (unlikely(!skb)) 376231d06aeSJörn Engel return; 377231d06aeSJörn Engel if (likely(atomic_read(&skb->users) == 1)) 378231d06aeSJörn Engel smp_rmb(); 379231d06aeSJörn Engel else if (likely(!atomic_dec_and_test(&skb->users))) 380231d06aeSJörn Engel return; 381231d06aeSJörn Engel __kfree_skb(skb); 382231d06aeSJörn Engel } 383231d06aeSJörn Engel 384231d06aeSJörn Engel /** 3851da177e4SLinus Torvalds * skb_clone - duplicate an sk_buff 3861da177e4SLinus Torvalds * @skb: buffer to clone 3871da177e4SLinus Torvalds * @gfp_mask: allocation priority 3881da177e4SLinus Torvalds * 3891da177e4SLinus Torvalds * Duplicate an &sk_buff. The new one is not owned by a socket. Both 3901da177e4SLinus Torvalds * copies share the same packet data but not structure. The new 3911da177e4SLinus Torvalds * buffer has a reference count of 1. If the allocation fails the 3921da177e4SLinus Torvalds * function returns %NULL otherwise the new buffer is returned. 3931da177e4SLinus Torvalds * 3941da177e4SLinus Torvalds * If this function is called from an interrupt gfp_mask() must be 3951da177e4SLinus Torvalds * %GFP_ATOMIC. 3961da177e4SLinus Torvalds */ 3971da177e4SLinus Torvalds 398dd0fc66fSAl Viro struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) 3991da177e4SLinus Torvalds { 400d179cd12SDavid S. Miller struct sk_buff *n; 4011da177e4SLinus Torvalds 402d179cd12SDavid S. Miller n = skb + 1; 403d179cd12SDavid S. Miller if (skb->fclone == SKB_FCLONE_ORIG && 404d179cd12SDavid S. Miller n->fclone == SKB_FCLONE_UNAVAILABLE) { 405d179cd12SDavid S. Miller atomic_t *fclone_ref = (atomic_t *) (n + 1); 406d179cd12SDavid S. Miller n->fclone = SKB_FCLONE_CLONE; 407d179cd12SDavid S. Miller atomic_inc(fclone_ref); 408d179cd12SDavid S. Miller } else { 409d179cd12SDavid S. Miller n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); 4101da177e4SLinus Torvalds if (!n) 4111da177e4SLinus Torvalds return NULL; 412d179cd12SDavid S. Miller n->fclone = SKB_FCLONE_UNAVAILABLE; 413d179cd12SDavid S. Miller } 4141da177e4SLinus Torvalds 4151da177e4SLinus Torvalds #define C(x) n->x = skb->x 4161da177e4SLinus Torvalds 4171da177e4SLinus Torvalds n->next = n->prev = NULL; 4181da177e4SLinus Torvalds n->sk = NULL; 419a61bbcf2SPatrick McHardy C(tstamp); 4201da177e4SLinus Torvalds C(dev); 4211da177e4SLinus Torvalds C(h); 4221da177e4SLinus Torvalds C(nh); 4231da177e4SLinus Torvalds C(mac); 4241da177e4SLinus Torvalds C(dst); 4251da177e4SLinus Torvalds dst_clone(skb->dst); 4261da177e4SLinus Torvalds C(sp); 4271da177e4SLinus Torvalds #ifdef CONFIG_INET 4281da177e4SLinus Torvalds secpath_get(skb->sp); 4291da177e4SLinus Torvalds #endif 4301da177e4SLinus Torvalds memcpy(n->cb, skb->cb, sizeof(skb->cb)); 4311da177e4SLinus Torvalds C(len); 4321da177e4SLinus Torvalds C(data_len); 4331da177e4SLinus Torvalds C(csum); 4341da177e4SLinus Torvalds C(local_df); 4351da177e4SLinus Torvalds n->cloned = 1; 4361da177e4SLinus Torvalds n->nohdr = 0; 4371da177e4SLinus Torvalds C(pkt_type); 4381da177e4SLinus Torvalds C(ip_summed); 4391da177e4SLinus Torvalds C(priority); 440a8372f03SYOSHIFUJI Hideaki #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 441a8372f03SYOSHIFUJI Hideaki C(ipvs_property); 442a8372f03SYOSHIFUJI Hideaki #endif 4431da177e4SLinus Torvalds C(protocol); 4441da177e4SLinus Torvalds n->destructor = NULL; 4451da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 4461da177e4SLinus Torvalds C(nfmark); 4471da177e4SLinus Torvalds C(nfct); 4481da177e4SLinus Torvalds nf_conntrack_get(skb->nfct); 4491da177e4SLinus Torvalds C(nfctinfo); 4509fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4519fb9cbb1SYasuyuki Kozakai C(nfct_reasm); 4529fb9cbb1SYasuyuki Kozakai nf_conntrack_get_reasm(skb->nfct_reasm); 4539fb9cbb1SYasuyuki Kozakai #endif 4541da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 4551da177e4SLinus Torvalds C(nf_bridge); 4561da177e4SLinus Torvalds nf_bridge_get(skb->nf_bridge); 4571da177e4SLinus Torvalds #endif 4581da177e4SLinus Torvalds #endif /*CONFIG_NETFILTER*/ 4591da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 4601da177e4SLinus Torvalds C(tc_index); 4611da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 4621da177e4SLinus Torvalds n->tc_verd = SET_TC_VERD(skb->tc_verd,0); 463b72f6eccSDavid S. Miller n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd); 464b72f6eccSDavid S. Miller n->tc_verd = CLR_TC_MUNGED(n->tc_verd); 4651da177e4SLinus Torvalds C(input_dev); 4661da177e4SLinus Torvalds #endif 467984bc16cSJames Morris skb_copy_secmark(n, skb); 4681da177e4SLinus Torvalds #endif 4691da177e4SLinus Torvalds C(truesize); 4701da177e4SLinus Torvalds atomic_set(&n->users, 1); 4711da177e4SLinus Torvalds C(head); 4721da177e4SLinus Torvalds C(data); 4731da177e4SLinus Torvalds C(tail); 4741da177e4SLinus Torvalds C(end); 4751da177e4SLinus Torvalds 4761da177e4SLinus Torvalds atomic_inc(&(skb_shinfo(skb)->dataref)); 4771da177e4SLinus Torvalds skb->cloned = 1; 4781da177e4SLinus Torvalds 4791da177e4SLinus Torvalds return n; 4801da177e4SLinus Torvalds } 4811da177e4SLinus Torvalds 4821da177e4SLinus Torvalds static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 4831da177e4SLinus Torvalds { 4841da177e4SLinus Torvalds /* 4851da177e4SLinus Torvalds * Shift between the two data areas in bytes 4861da177e4SLinus Torvalds */ 4871da177e4SLinus Torvalds unsigned long offset = new->data - old->data; 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvalds new->sk = NULL; 4901da177e4SLinus Torvalds new->dev = old->dev; 4911da177e4SLinus Torvalds new->priority = old->priority; 4921da177e4SLinus Torvalds new->protocol = old->protocol; 4931da177e4SLinus Torvalds new->dst = dst_clone(old->dst); 4941da177e4SLinus Torvalds #ifdef CONFIG_INET 4951da177e4SLinus Torvalds new->sp = secpath_get(old->sp); 4961da177e4SLinus Torvalds #endif 4971da177e4SLinus Torvalds new->h.raw = old->h.raw + offset; 4981da177e4SLinus Torvalds new->nh.raw = old->nh.raw + offset; 4991da177e4SLinus Torvalds new->mac.raw = old->mac.raw + offset; 5001da177e4SLinus Torvalds memcpy(new->cb, old->cb, sizeof(old->cb)); 5011da177e4SLinus Torvalds new->local_df = old->local_df; 502d179cd12SDavid S. Miller new->fclone = SKB_FCLONE_UNAVAILABLE; 5031da177e4SLinus Torvalds new->pkt_type = old->pkt_type; 504a61bbcf2SPatrick McHardy new->tstamp = old->tstamp; 5051da177e4SLinus Torvalds new->destructor = NULL; 5061da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 5071da177e4SLinus Torvalds new->nfmark = old->nfmark; 5081da177e4SLinus Torvalds new->nfct = old->nfct; 5091da177e4SLinus Torvalds nf_conntrack_get(old->nfct); 5101da177e4SLinus Torvalds new->nfctinfo = old->nfctinfo; 5119fb9cbb1SYasuyuki Kozakai #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 5129fb9cbb1SYasuyuki Kozakai new->nfct_reasm = old->nfct_reasm; 5139fb9cbb1SYasuyuki Kozakai nf_conntrack_get_reasm(old->nfct_reasm); 5149fb9cbb1SYasuyuki Kozakai #endif 515c98d80edSJulian Anastasov #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) 516c98d80edSJulian Anastasov new->ipvs_property = old->ipvs_property; 517c98d80edSJulian Anastasov #endif 5181da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 5191da177e4SLinus Torvalds new->nf_bridge = old->nf_bridge; 5201da177e4SLinus Torvalds nf_bridge_get(old->nf_bridge); 5211da177e4SLinus Torvalds #endif 5221da177e4SLinus Torvalds #endif 5231da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 5241da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 5251da177e4SLinus Torvalds new->tc_verd = old->tc_verd; 5261da177e4SLinus Torvalds #endif 5271da177e4SLinus Torvalds new->tc_index = old->tc_index; 5281da177e4SLinus Torvalds #endif 529984bc16cSJames Morris skb_copy_secmark(new, old); 5301da177e4SLinus Torvalds atomic_set(&new->users, 1); 5311da177e4SLinus Torvalds skb_shinfo(new)->tso_size = skb_shinfo(old)->tso_size; 5321da177e4SLinus Torvalds skb_shinfo(new)->tso_segs = skb_shinfo(old)->tso_segs; 5331da177e4SLinus Torvalds } 5341da177e4SLinus Torvalds 5351da177e4SLinus Torvalds /** 5361da177e4SLinus Torvalds * skb_copy - create private copy of an sk_buff 5371da177e4SLinus Torvalds * @skb: buffer to copy 5381da177e4SLinus Torvalds * @gfp_mask: allocation priority 5391da177e4SLinus Torvalds * 5401da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data. This is used when the 5411da177e4SLinus Torvalds * caller wishes to modify the data and needs a private copy of the 5421da177e4SLinus Torvalds * data to alter. Returns %NULL on failure or the pointer to the buffer 5431da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 5441da177e4SLinus Torvalds * 5451da177e4SLinus Torvalds * As by-product this function converts non-linear &sk_buff to linear 5461da177e4SLinus Torvalds * one, so that &sk_buff becomes completely private and caller is allowed 5471da177e4SLinus Torvalds * to modify all the data of returned buffer. This means that this 5481da177e4SLinus Torvalds * function is not recommended for use in circumstances when only 5491da177e4SLinus Torvalds * header is going to be modified. Use pskb_copy() instead. 5501da177e4SLinus Torvalds */ 5511da177e4SLinus Torvalds 552dd0fc66fSAl Viro struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) 5531da177e4SLinus Torvalds { 5541da177e4SLinus Torvalds int headerlen = skb->data - skb->head; 5551da177e4SLinus Torvalds /* 5561da177e4SLinus Torvalds * Allocate the copy buffer 5571da177e4SLinus Torvalds */ 5581da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len, 5591da177e4SLinus Torvalds gfp_mask); 5601da177e4SLinus Torvalds if (!n) 5611da177e4SLinus Torvalds return NULL; 5621da177e4SLinus Torvalds 5631da177e4SLinus Torvalds /* Set the data pointer */ 5641da177e4SLinus Torvalds skb_reserve(n, headerlen); 5651da177e4SLinus Torvalds /* Set the tail pointer and length */ 5661da177e4SLinus Torvalds skb_put(n, skb->len); 5671da177e4SLinus Torvalds n->csum = skb->csum; 5681da177e4SLinus Torvalds n->ip_summed = skb->ip_summed; 5691da177e4SLinus Torvalds 5701da177e4SLinus Torvalds if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) 5711da177e4SLinus Torvalds BUG(); 5721da177e4SLinus Torvalds 5731da177e4SLinus Torvalds copy_skb_header(n, skb); 5741da177e4SLinus Torvalds return n; 5751da177e4SLinus Torvalds } 5761da177e4SLinus Torvalds 5771da177e4SLinus Torvalds 5781da177e4SLinus Torvalds /** 5791da177e4SLinus Torvalds * pskb_copy - create copy of an sk_buff with private head. 5801da177e4SLinus Torvalds * @skb: buffer to copy 5811da177e4SLinus Torvalds * @gfp_mask: allocation priority 5821da177e4SLinus Torvalds * 5831da177e4SLinus Torvalds * Make a copy of both an &sk_buff and part of its data, located 5841da177e4SLinus Torvalds * in header. Fragmented data remain shared. This is used when 5851da177e4SLinus Torvalds * the caller wishes to modify only header of &sk_buff and needs 5861da177e4SLinus Torvalds * private copy of the header to alter. Returns %NULL on failure 5871da177e4SLinus Torvalds * or the pointer to the buffer on success. 5881da177e4SLinus Torvalds * The returned buffer has a reference count of 1. 5891da177e4SLinus Torvalds */ 5901da177e4SLinus Torvalds 591dd0fc66fSAl Viro struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask) 5921da177e4SLinus Torvalds { 5931da177e4SLinus Torvalds /* 5941da177e4SLinus Torvalds * Allocate the copy buffer 5951da177e4SLinus Torvalds */ 5961da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask); 5971da177e4SLinus Torvalds 5981da177e4SLinus Torvalds if (!n) 5991da177e4SLinus Torvalds goto out; 6001da177e4SLinus Torvalds 6011da177e4SLinus Torvalds /* Set the data pointer */ 6021da177e4SLinus Torvalds skb_reserve(n, skb->data - skb->head); 6031da177e4SLinus Torvalds /* Set the tail pointer and length */ 6041da177e4SLinus Torvalds skb_put(n, skb_headlen(skb)); 6051da177e4SLinus Torvalds /* Copy the bytes */ 6061da177e4SLinus Torvalds memcpy(n->data, skb->data, n->len); 6071da177e4SLinus Torvalds n->csum = skb->csum; 6081da177e4SLinus Torvalds n->ip_summed = skb->ip_summed; 6091da177e4SLinus Torvalds 6101da177e4SLinus Torvalds n->data_len = skb->data_len; 6111da177e4SLinus Torvalds n->len = skb->len; 6121da177e4SLinus Torvalds 6131da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 6141da177e4SLinus Torvalds int i; 6151da177e4SLinus Torvalds 6161da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 6171da177e4SLinus Torvalds skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; 6181da177e4SLinus Torvalds get_page(skb_shinfo(n)->frags[i].page); 6191da177e4SLinus Torvalds } 6201da177e4SLinus Torvalds skb_shinfo(n)->nr_frags = i; 6211da177e4SLinus Torvalds } 6221da177e4SLinus Torvalds 6231da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 6241da177e4SLinus Torvalds skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; 6251da177e4SLinus Torvalds skb_clone_fraglist(n); 6261da177e4SLinus Torvalds } 6271da177e4SLinus Torvalds 6281da177e4SLinus Torvalds copy_skb_header(n, skb); 6291da177e4SLinus Torvalds out: 6301da177e4SLinus Torvalds return n; 6311da177e4SLinus Torvalds } 6321da177e4SLinus Torvalds 6331da177e4SLinus Torvalds /** 6341da177e4SLinus Torvalds * pskb_expand_head - reallocate header of &sk_buff 6351da177e4SLinus Torvalds * @skb: buffer to reallocate 6361da177e4SLinus Torvalds * @nhead: room to add at head 6371da177e4SLinus Torvalds * @ntail: room to add at tail 6381da177e4SLinus Torvalds * @gfp_mask: allocation priority 6391da177e4SLinus Torvalds * 6401da177e4SLinus Torvalds * Expands (or creates identical copy, if &nhead and &ntail are zero) 6411da177e4SLinus Torvalds * header of skb. &sk_buff itself is not changed. &sk_buff MUST have 6421da177e4SLinus Torvalds * reference count of 1. Returns zero in the case of success or error, 6431da177e4SLinus Torvalds * if expansion failed. In the last case, &sk_buff is not changed. 6441da177e4SLinus Torvalds * 6451da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 6461da177e4SLinus Torvalds * reloaded after call to this function. 6471da177e4SLinus Torvalds */ 6481da177e4SLinus Torvalds 64986a76cafSVictor Fusco int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, 650dd0fc66fSAl Viro gfp_t gfp_mask) 6511da177e4SLinus Torvalds { 6521da177e4SLinus Torvalds int i; 6531da177e4SLinus Torvalds u8 *data; 6541da177e4SLinus Torvalds int size = nhead + (skb->end - skb->head) + ntail; 6551da177e4SLinus Torvalds long off; 6561da177e4SLinus Torvalds 6571da177e4SLinus Torvalds if (skb_shared(skb)) 6581da177e4SLinus Torvalds BUG(); 6591da177e4SLinus Torvalds 6601da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 6611da177e4SLinus Torvalds 6621da177e4SLinus Torvalds data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); 6631da177e4SLinus Torvalds if (!data) 6641da177e4SLinus Torvalds goto nodata; 6651da177e4SLinus Torvalds 6661da177e4SLinus Torvalds /* Copy only real data... and, alas, header. This should be 6671da177e4SLinus Torvalds * optimized for the cases when header is void. */ 6681da177e4SLinus Torvalds memcpy(data + nhead, skb->head, skb->tail - skb->head); 6691da177e4SLinus Torvalds memcpy(data + size, skb->end, sizeof(struct skb_shared_info)); 6701da177e4SLinus Torvalds 6711da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 6721da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 6751da177e4SLinus Torvalds skb_clone_fraglist(skb); 6761da177e4SLinus Torvalds 6771da177e4SLinus Torvalds skb_release_data(skb); 6781da177e4SLinus Torvalds 6791da177e4SLinus Torvalds off = (data + nhead) - skb->head; 6801da177e4SLinus Torvalds 6811da177e4SLinus Torvalds skb->head = data; 6821da177e4SLinus Torvalds skb->end = data + size; 6831da177e4SLinus Torvalds skb->data += off; 6841da177e4SLinus Torvalds skb->tail += off; 6851da177e4SLinus Torvalds skb->mac.raw += off; 6861da177e4SLinus Torvalds skb->h.raw += off; 6871da177e4SLinus Torvalds skb->nh.raw += off; 6881da177e4SLinus Torvalds skb->cloned = 0; 6891da177e4SLinus Torvalds skb->nohdr = 0; 6901da177e4SLinus Torvalds atomic_set(&skb_shinfo(skb)->dataref, 1); 6911da177e4SLinus Torvalds return 0; 6921da177e4SLinus Torvalds 6931da177e4SLinus Torvalds nodata: 6941da177e4SLinus Torvalds return -ENOMEM; 6951da177e4SLinus Torvalds } 6961da177e4SLinus Torvalds 6971da177e4SLinus Torvalds /* Make private copy of skb with writable head and some headroom */ 6981da177e4SLinus Torvalds 6991da177e4SLinus Torvalds struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) 7001da177e4SLinus Torvalds { 7011da177e4SLinus Torvalds struct sk_buff *skb2; 7021da177e4SLinus Torvalds int delta = headroom - skb_headroom(skb); 7031da177e4SLinus Torvalds 7041da177e4SLinus Torvalds if (delta <= 0) 7051da177e4SLinus Torvalds skb2 = pskb_copy(skb, GFP_ATOMIC); 7061da177e4SLinus Torvalds else { 7071da177e4SLinus Torvalds skb2 = skb_clone(skb, GFP_ATOMIC); 7081da177e4SLinus Torvalds if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, 7091da177e4SLinus Torvalds GFP_ATOMIC)) { 7101da177e4SLinus Torvalds kfree_skb(skb2); 7111da177e4SLinus Torvalds skb2 = NULL; 7121da177e4SLinus Torvalds } 7131da177e4SLinus Torvalds } 7141da177e4SLinus Torvalds return skb2; 7151da177e4SLinus Torvalds } 7161da177e4SLinus Torvalds 7171da177e4SLinus Torvalds 7181da177e4SLinus Torvalds /** 7191da177e4SLinus Torvalds * skb_copy_expand - copy and expand sk_buff 7201da177e4SLinus Torvalds * @skb: buffer to copy 7211da177e4SLinus Torvalds * @newheadroom: new free bytes at head 7221da177e4SLinus Torvalds * @newtailroom: new free bytes at tail 7231da177e4SLinus Torvalds * @gfp_mask: allocation priority 7241da177e4SLinus Torvalds * 7251da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data and while doing so 7261da177e4SLinus Torvalds * allocate additional space. 7271da177e4SLinus Torvalds * 7281da177e4SLinus Torvalds * This is used when the caller wishes to modify the data and needs a 7291da177e4SLinus Torvalds * private copy of the data to alter as well as more space for new fields. 7301da177e4SLinus Torvalds * Returns %NULL on failure or the pointer to the buffer 7311da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 7321da177e4SLinus Torvalds * 7331da177e4SLinus Torvalds * You must pass %GFP_ATOMIC as the allocation priority if this function 7341da177e4SLinus Torvalds * is called from an interrupt. 7351da177e4SLinus Torvalds * 7361da177e4SLinus Torvalds * BUG ALERT: ip_summed is not copied. Why does this work? Is it used 7371da177e4SLinus Torvalds * only by netfilter in the cases when checksum is recalculated? --ANK 7381da177e4SLinus Torvalds */ 7391da177e4SLinus Torvalds struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 74086a76cafSVictor Fusco int newheadroom, int newtailroom, 741dd0fc66fSAl Viro gfp_t gfp_mask) 7421da177e4SLinus Torvalds { 7431da177e4SLinus Torvalds /* 7441da177e4SLinus Torvalds * Allocate the copy buffer 7451da177e4SLinus Torvalds */ 7461da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, 7471da177e4SLinus Torvalds gfp_mask); 7481da177e4SLinus Torvalds int head_copy_len, head_copy_off; 7491da177e4SLinus Torvalds 7501da177e4SLinus Torvalds if (!n) 7511da177e4SLinus Torvalds return NULL; 7521da177e4SLinus Torvalds 7531da177e4SLinus Torvalds skb_reserve(n, newheadroom); 7541da177e4SLinus Torvalds 7551da177e4SLinus Torvalds /* Set the tail pointer and length */ 7561da177e4SLinus Torvalds skb_put(n, skb->len); 7571da177e4SLinus Torvalds 7581da177e4SLinus Torvalds head_copy_len = skb_headroom(skb); 7591da177e4SLinus Torvalds head_copy_off = 0; 7601da177e4SLinus Torvalds if (newheadroom <= head_copy_len) 7611da177e4SLinus Torvalds head_copy_len = newheadroom; 7621da177e4SLinus Torvalds else 7631da177e4SLinus Torvalds head_copy_off = newheadroom - head_copy_len; 7641da177e4SLinus Torvalds 7651da177e4SLinus Torvalds /* Copy the linear header and data. */ 7661da177e4SLinus Torvalds if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, 7671da177e4SLinus Torvalds skb->len + head_copy_len)) 7681da177e4SLinus Torvalds BUG(); 7691da177e4SLinus Torvalds 7701da177e4SLinus Torvalds copy_skb_header(n, skb); 7711da177e4SLinus Torvalds 7721da177e4SLinus Torvalds return n; 7731da177e4SLinus Torvalds } 7741da177e4SLinus Torvalds 7751da177e4SLinus Torvalds /** 7761da177e4SLinus Torvalds * skb_pad - zero pad the tail of an skb 7771da177e4SLinus Torvalds * @skb: buffer to pad 7781da177e4SLinus Torvalds * @pad: space to pad 7791da177e4SLinus Torvalds * 7801da177e4SLinus Torvalds * Ensure that a buffer is followed by a padding area that is zero 7811da177e4SLinus Torvalds * filled. Used by network drivers which may DMA or transfer data 7821da177e4SLinus Torvalds * beyond the buffer end onto the wire. 7831da177e4SLinus Torvalds * 7841da177e4SLinus Torvalds * May return NULL in out of memory cases. 7851da177e4SLinus Torvalds */ 7861da177e4SLinus Torvalds 7871da177e4SLinus Torvalds struct sk_buff *skb_pad(struct sk_buff *skb, int pad) 7881da177e4SLinus Torvalds { 7891da177e4SLinus Torvalds struct sk_buff *nskb; 7901da177e4SLinus Torvalds 7911da177e4SLinus Torvalds /* If the skbuff is non linear tailroom is always zero.. */ 7921da177e4SLinus Torvalds if (skb_tailroom(skb) >= pad) { 7931da177e4SLinus Torvalds memset(skb->data+skb->len, 0, pad); 7941da177e4SLinus Torvalds return skb; 7951da177e4SLinus Torvalds } 7961da177e4SLinus Torvalds 7971da177e4SLinus Torvalds nskb = skb_copy_expand(skb, skb_headroom(skb), skb_tailroom(skb) + pad, GFP_ATOMIC); 7981da177e4SLinus Torvalds kfree_skb(skb); 7991da177e4SLinus Torvalds if (nskb) 8001da177e4SLinus Torvalds memset(nskb->data+nskb->len, 0, pad); 8011da177e4SLinus Torvalds return nskb; 8021da177e4SLinus Torvalds } 8031da177e4SLinus Torvalds 8041da177e4SLinus Torvalds /* Trims skb to length len. It can change skb pointers, if "realloc" is 1. 8051da177e4SLinus Torvalds * If realloc==0 and trimming is impossible without change of data, 8061da177e4SLinus Torvalds * it is BUG(). 8071da177e4SLinus Torvalds */ 8081da177e4SLinus Torvalds 8091da177e4SLinus Torvalds int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc) 8101da177e4SLinus Torvalds { 8111da177e4SLinus Torvalds int offset = skb_headlen(skb); 8121da177e4SLinus Torvalds int nfrags = skb_shinfo(skb)->nr_frags; 8131da177e4SLinus Torvalds int i; 8141da177e4SLinus Torvalds 8151da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 8161da177e4SLinus Torvalds int end = offset + skb_shinfo(skb)->frags[i].size; 8171da177e4SLinus Torvalds if (end > len) { 8181da177e4SLinus Torvalds if (skb_cloned(skb)) { 81909a62660SKris Katterjohn BUG_ON(!realloc); 8201da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 8211da177e4SLinus Torvalds return -ENOMEM; 8221da177e4SLinus Torvalds } 8231da177e4SLinus Torvalds if (len <= offset) { 8241da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 8251da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags--; 8261da177e4SLinus Torvalds } else { 8271da177e4SLinus Torvalds skb_shinfo(skb)->frags[i].size = len - offset; 8281da177e4SLinus Torvalds } 8291da177e4SLinus Torvalds } 8301da177e4SLinus Torvalds offset = end; 8311da177e4SLinus Torvalds } 8321da177e4SLinus Torvalds 8331da177e4SLinus Torvalds if (offset < len) { 8341da177e4SLinus Torvalds skb->data_len -= skb->len - len; 8351da177e4SLinus Torvalds skb->len = len; 8361da177e4SLinus Torvalds } else { 8371da177e4SLinus Torvalds if (len <= skb_headlen(skb)) { 8381da177e4SLinus Torvalds skb->len = len; 8391da177e4SLinus Torvalds skb->data_len = 0; 8401da177e4SLinus Torvalds skb->tail = skb->data + len; 8411da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list && !skb_cloned(skb)) 8421da177e4SLinus Torvalds skb_drop_fraglist(skb); 8431da177e4SLinus Torvalds } else { 8441da177e4SLinus Torvalds skb->data_len -= skb->len - len; 8451da177e4SLinus Torvalds skb->len = len; 8461da177e4SLinus Torvalds } 8471da177e4SLinus Torvalds } 8481da177e4SLinus Torvalds 8491da177e4SLinus Torvalds return 0; 8501da177e4SLinus Torvalds } 8511da177e4SLinus Torvalds 8521da177e4SLinus Torvalds /** 8531da177e4SLinus Torvalds * __pskb_pull_tail - advance tail of skb header 8541da177e4SLinus Torvalds * @skb: buffer to reallocate 8551da177e4SLinus Torvalds * @delta: number of bytes to advance tail 8561da177e4SLinus Torvalds * 8571da177e4SLinus Torvalds * The function makes a sense only on a fragmented &sk_buff, 8581da177e4SLinus Torvalds * it expands header moving its tail forward and copying necessary 8591da177e4SLinus Torvalds * data from fragmented part. 8601da177e4SLinus Torvalds * 8611da177e4SLinus Torvalds * &sk_buff MUST have reference count of 1. 8621da177e4SLinus Torvalds * 8631da177e4SLinus Torvalds * Returns %NULL (and &sk_buff does not change) if pull failed 8641da177e4SLinus Torvalds * or value of new tail of skb in the case of success. 8651da177e4SLinus Torvalds * 8661da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 8671da177e4SLinus Torvalds * reloaded after call to this function. 8681da177e4SLinus Torvalds */ 8691da177e4SLinus Torvalds 8701da177e4SLinus Torvalds /* Moves tail of skb head forward, copying data from fragmented part, 8711da177e4SLinus Torvalds * when it is necessary. 8721da177e4SLinus Torvalds * 1. It may fail due to malloc failure. 8731da177e4SLinus Torvalds * 2. It may change skb pointers. 8741da177e4SLinus Torvalds * 8751da177e4SLinus Torvalds * It is pretty complicated. Luckily, it is called only in exceptional cases. 8761da177e4SLinus Torvalds */ 8771da177e4SLinus Torvalds unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) 8781da177e4SLinus Torvalds { 8791da177e4SLinus Torvalds /* If skb has not enough free space at tail, get new one 8801da177e4SLinus Torvalds * plus 128 bytes for future expansions. If we have enough 8811da177e4SLinus Torvalds * room at tail, reallocate without expansion only if skb is cloned. 8821da177e4SLinus Torvalds */ 8831da177e4SLinus Torvalds int i, k, eat = (skb->tail + delta) - skb->end; 8841da177e4SLinus Torvalds 8851da177e4SLinus Torvalds if (eat > 0 || skb_cloned(skb)) { 8861da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, 8871da177e4SLinus Torvalds GFP_ATOMIC)) 8881da177e4SLinus Torvalds return NULL; 8891da177e4SLinus Torvalds } 8901da177e4SLinus Torvalds 8911da177e4SLinus Torvalds if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta)) 8921da177e4SLinus Torvalds BUG(); 8931da177e4SLinus Torvalds 8941da177e4SLinus Torvalds /* Optimization: no fragments, no reasons to preestimate 8951da177e4SLinus Torvalds * size of pulled pages. Superb. 8961da177e4SLinus Torvalds */ 8971da177e4SLinus Torvalds if (!skb_shinfo(skb)->frag_list) 8981da177e4SLinus Torvalds goto pull_pages; 8991da177e4SLinus Torvalds 9001da177e4SLinus Torvalds /* Estimate size of pulled pages. */ 9011da177e4SLinus Torvalds eat = delta; 9021da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 9031da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size >= eat) 9041da177e4SLinus Torvalds goto pull_pages; 9051da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 9061da177e4SLinus Torvalds } 9071da177e4SLinus Torvalds 9081da177e4SLinus Torvalds /* If we need update frag list, we are in troubles. 9091da177e4SLinus Torvalds * Certainly, it possible to add an offset to skb data, 9101da177e4SLinus Torvalds * but taking into account that pulling is expected to 9111da177e4SLinus Torvalds * be very rare operation, it is worth to fight against 9121da177e4SLinus Torvalds * further bloating skb head and crucify ourselves here instead. 9131da177e4SLinus Torvalds * Pure masohism, indeed. 8)8) 9141da177e4SLinus Torvalds */ 9151da177e4SLinus Torvalds if (eat) { 9161da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 9171da177e4SLinus Torvalds struct sk_buff *clone = NULL; 9181da177e4SLinus Torvalds struct sk_buff *insp = NULL; 9191da177e4SLinus Torvalds 9201da177e4SLinus Torvalds do { 92109a62660SKris Katterjohn BUG_ON(!list); 9221da177e4SLinus Torvalds 9231da177e4SLinus Torvalds if (list->len <= eat) { 9241da177e4SLinus Torvalds /* Eaten as whole. */ 9251da177e4SLinus Torvalds eat -= list->len; 9261da177e4SLinus Torvalds list = list->next; 9271da177e4SLinus Torvalds insp = list; 9281da177e4SLinus Torvalds } else { 9291da177e4SLinus Torvalds /* Eaten partially. */ 9301da177e4SLinus Torvalds 9311da177e4SLinus Torvalds if (skb_shared(list)) { 9321da177e4SLinus Torvalds /* Sucks! We need to fork list. :-( */ 9331da177e4SLinus Torvalds clone = skb_clone(list, GFP_ATOMIC); 9341da177e4SLinus Torvalds if (!clone) 9351da177e4SLinus Torvalds return NULL; 9361da177e4SLinus Torvalds insp = list->next; 9371da177e4SLinus Torvalds list = clone; 9381da177e4SLinus Torvalds } else { 9391da177e4SLinus Torvalds /* This may be pulled without 9401da177e4SLinus Torvalds * problems. */ 9411da177e4SLinus Torvalds insp = list; 9421da177e4SLinus Torvalds } 9431da177e4SLinus Torvalds if (!pskb_pull(list, eat)) { 9441da177e4SLinus Torvalds if (clone) 9451da177e4SLinus Torvalds kfree_skb(clone); 9461da177e4SLinus Torvalds return NULL; 9471da177e4SLinus Torvalds } 9481da177e4SLinus Torvalds break; 9491da177e4SLinus Torvalds } 9501da177e4SLinus Torvalds } while (eat); 9511da177e4SLinus Torvalds 9521da177e4SLinus Torvalds /* Free pulled out fragments. */ 9531da177e4SLinus Torvalds while ((list = skb_shinfo(skb)->frag_list) != insp) { 9541da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = list->next; 9551da177e4SLinus Torvalds kfree_skb(list); 9561da177e4SLinus Torvalds } 9571da177e4SLinus Torvalds /* And insert new clone at head. */ 9581da177e4SLinus Torvalds if (clone) { 9591da177e4SLinus Torvalds clone->next = list; 9601da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = clone; 9611da177e4SLinus Torvalds } 9621da177e4SLinus Torvalds } 9631da177e4SLinus Torvalds /* Success! Now we may commit changes to skb data. */ 9641da177e4SLinus Torvalds 9651da177e4SLinus Torvalds pull_pages: 9661da177e4SLinus Torvalds eat = delta; 9671da177e4SLinus Torvalds k = 0; 9681da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 9691da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size <= eat) { 9701da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 9711da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 9721da177e4SLinus Torvalds } else { 9731da177e4SLinus Torvalds skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; 9741da177e4SLinus Torvalds if (eat) { 9751da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].page_offset += eat; 9761da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].size -= eat; 9771da177e4SLinus Torvalds eat = 0; 9781da177e4SLinus Torvalds } 9791da177e4SLinus Torvalds k++; 9801da177e4SLinus Torvalds } 9811da177e4SLinus Torvalds } 9821da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = k; 9831da177e4SLinus Torvalds 9841da177e4SLinus Torvalds skb->tail += delta; 9851da177e4SLinus Torvalds skb->data_len -= delta; 9861da177e4SLinus Torvalds 9871da177e4SLinus Torvalds return skb->tail; 9881da177e4SLinus Torvalds } 9891da177e4SLinus Torvalds 9901da177e4SLinus Torvalds /* Copy some data bits from skb to kernel buffer. */ 9911da177e4SLinus Torvalds 9921da177e4SLinus Torvalds int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) 9931da177e4SLinus Torvalds { 9941da177e4SLinus Torvalds int i, copy; 9951da177e4SLinus Torvalds int start = skb_headlen(skb); 9961da177e4SLinus Torvalds 9971da177e4SLinus Torvalds if (offset > (int)skb->len - len) 9981da177e4SLinus Torvalds goto fault; 9991da177e4SLinus Torvalds 10001da177e4SLinus Torvalds /* Copy header. */ 10011da177e4SLinus Torvalds if ((copy = start - offset) > 0) { 10021da177e4SLinus Torvalds if (copy > len) 10031da177e4SLinus Torvalds copy = len; 10041da177e4SLinus Torvalds memcpy(to, skb->data + offset, copy); 10051da177e4SLinus Torvalds if ((len -= copy) == 0) 10061da177e4SLinus Torvalds return 0; 10071da177e4SLinus Torvalds offset += copy; 10081da177e4SLinus Torvalds to += copy; 10091da177e4SLinus Torvalds } 10101da177e4SLinus Torvalds 10111da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 10121da177e4SLinus Torvalds int end; 10131da177e4SLinus Torvalds 10141da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 10151da177e4SLinus Torvalds 10161da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 10171da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 10181da177e4SLinus Torvalds u8 *vaddr; 10191da177e4SLinus Torvalds 10201da177e4SLinus Torvalds if (copy > len) 10211da177e4SLinus Torvalds copy = len; 10221da177e4SLinus Torvalds 10231da177e4SLinus Torvalds vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); 10241da177e4SLinus Torvalds memcpy(to, 10251da177e4SLinus Torvalds vaddr + skb_shinfo(skb)->frags[i].page_offset+ 10261da177e4SLinus Torvalds offset - start, copy); 10271da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 10281da177e4SLinus Torvalds 10291da177e4SLinus Torvalds if ((len -= copy) == 0) 10301da177e4SLinus Torvalds return 0; 10311da177e4SLinus Torvalds offset += copy; 10321da177e4SLinus Torvalds to += copy; 10331da177e4SLinus Torvalds } 10341da177e4SLinus Torvalds start = end; 10351da177e4SLinus Torvalds } 10361da177e4SLinus Torvalds 10371da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 10381da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 10391da177e4SLinus Torvalds 10401da177e4SLinus Torvalds for (; list; list = list->next) { 10411da177e4SLinus Torvalds int end; 10421da177e4SLinus Torvalds 10431da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 10441da177e4SLinus Torvalds 10451da177e4SLinus Torvalds end = start + list->len; 10461da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 10471da177e4SLinus Torvalds if (copy > len) 10481da177e4SLinus Torvalds copy = len; 10491da177e4SLinus Torvalds if (skb_copy_bits(list, offset - start, 10501da177e4SLinus Torvalds to, copy)) 10511da177e4SLinus Torvalds goto fault; 10521da177e4SLinus Torvalds if ((len -= copy) == 0) 10531da177e4SLinus Torvalds return 0; 10541da177e4SLinus Torvalds offset += copy; 10551da177e4SLinus Torvalds to += copy; 10561da177e4SLinus Torvalds } 10571da177e4SLinus Torvalds start = end; 10581da177e4SLinus Torvalds } 10591da177e4SLinus Torvalds } 10601da177e4SLinus Torvalds if (!len) 10611da177e4SLinus Torvalds return 0; 10621da177e4SLinus Torvalds 10631da177e4SLinus Torvalds fault: 10641da177e4SLinus Torvalds return -EFAULT; 10651da177e4SLinus Torvalds } 10661da177e4SLinus Torvalds 1067357b40a1SHerbert Xu /** 1068357b40a1SHerbert Xu * skb_store_bits - store bits from kernel buffer to skb 1069357b40a1SHerbert Xu * @skb: destination buffer 1070357b40a1SHerbert Xu * @offset: offset in destination 1071357b40a1SHerbert Xu * @from: source buffer 1072357b40a1SHerbert Xu * @len: number of bytes to copy 1073357b40a1SHerbert Xu * 1074357b40a1SHerbert Xu * Copy the specified number of bytes from the source buffer to the 1075357b40a1SHerbert Xu * destination skb. This function handles all the messy bits of 1076357b40a1SHerbert Xu * traversing fragment lists and such. 1077357b40a1SHerbert Xu */ 1078357b40a1SHerbert Xu 1079357b40a1SHerbert Xu int skb_store_bits(const struct sk_buff *skb, int offset, void *from, int len) 1080357b40a1SHerbert Xu { 1081357b40a1SHerbert Xu int i, copy; 1082357b40a1SHerbert Xu int start = skb_headlen(skb); 1083357b40a1SHerbert Xu 1084357b40a1SHerbert Xu if (offset > (int)skb->len - len) 1085357b40a1SHerbert Xu goto fault; 1086357b40a1SHerbert Xu 1087357b40a1SHerbert Xu if ((copy = start - offset) > 0) { 1088357b40a1SHerbert Xu if (copy > len) 1089357b40a1SHerbert Xu copy = len; 1090357b40a1SHerbert Xu memcpy(skb->data + offset, from, copy); 1091357b40a1SHerbert Xu if ((len -= copy) == 0) 1092357b40a1SHerbert Xu return 0; 1093357b40a1SHerbert Xu offset += copy; 1094357b40a1SHerbert Xu from += copy; 1095357b40a1SHerbert Xu } 1096357b40a1SHerbert Xu 1097357b40a1SHerbert Xu for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 1098357b40a1SHerbert Xu skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 1099357b40a1SHerbert Xu int end; 1100357b40a1SHerbert Xu 1101357b40a1SHerbert Xu BUG_TRAP(start <= offset + len); 1102357b40a1SHerbert Xu 1103357b40a1SHerbert Xu end = start + frag->size; 1104357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1105357b40a1SHerbert Xu u8 *vaddr; 1106357b40a1SHerbert Xu 1107357b40a1SHerbert Xu if (copy > len) 1108357b40a1SHerbert Xu copy = len; 1109357b40a1SHerbert Xu 1110357b40a1SHerbert Xu vaddr = kmap_skb_frag(frag); 1111357b40a1SHerbert Xu memcpy(vaddr + frag->page_offset + offset - start, 1112357b40a1SHerbert Xu from, copy); 1113357b40a1SHerbert Xu kunmap_skb_frag(vaddr); 1114357b40a1SHerbert Xu 1115357b40a1SHerbert Xu if ((len -= copy) == 0) 1116357b40a1SHerbert Xu return 0; 1117357b40a1SHerbert Xu offset += copy; 1118357b40a1SHerbert Xu from += copy; 1119357b40a1SHerbert Xu } 1120357b40a1SHerbert Xu start = end; 1121357b40a1SHerbert Xu } 1122357b40a1SHerbert Xu 1123357b40a1SHerbert Xu if (skb_shinfo(skb)->frag_list) { 1124357b40a1SHerbert Xu struct sk_buff *list = skb_shinfo(skb)->frag_list; 1125357b40a1SHerbert Xu 1126357b40a1SHerbert Xu for (; list; list = list->next) { 1127357b40a1SHerbert Xu int end; 1128357b40a1SHerbert Xu 1129357b40a1SHerbert Xu BUG_TRAP(start <= offset + len); 1130357b40a1SHerbert Xu 1131357b40a1SHerbert Xu end = start + list->len; 1132357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1133357b40a1SHerbert Xu if (copy > len) 1134357b40a1SHerbert Xu copy = len; 1135357b40a1SHerbert Xu if (skb_store_bits(list, offset - start, 1136357b40a1SHerbert Xu from, copy)) 1137357b40a1SHerbert Xu goto fault; 1138357b40a1SHerbert Xu if ((len -= copy) == 0) 1139357b40a1SHerbert Xu return 0; 1140357b40a1SHerbert Xu offset += copy; 1141357b40a1SHerbert Xu from += copy; 1142357b40a1SHerbert Xu } 1143357b40a1SHerbert Xu start = end; 1144357b40a1SHerbert Xu } 1145357b40a1SHerbert Xu } 1146357b40a1SHerbert Xu if (!len) 1147357b40a1SHerbert Xu return 0; 1148357b40a1SHerbert Xu 1149357b40a1SHerbert Xu fault: 1150357b40a1SHerbert Xu return -EFAULT; 1151357b40a1SHerbert Xu } 1152357b40a1SHerbert Xu 1153357b40a1SHerbert Xu EXPORT_SYMBOL(skb_store_bits); 1154357b40a1SHerbert Xu 11551da177e4SLinus Torvalds /* Checksum skb data. */ 11561da177e4SLinus Torvalds 11571da177e4SLinus Torvalds unsigned int skb_checksum(const struct sk_buff *skb, int offset, 11581da177e4SLinus Torvalds int len, unsigned int csum) 11591da177e4SLinus Torvalds { 11601da177e4SLinus Torvalds int start = skb_headlen(skb); 11611da177e4SLinus Torvalds int i, copy = start - offset; 11621da177e4SLinus Torvalds int pos = 0; 11631da177e4SLinus Torvalds 11641da177e4SLinus Torvalds /* Checksum header. */ 11651da177e4SLinus Torvalds if (copy > 0) { 11661da177e4SLinus Torvalds if (copy > len) 11671da177e4SLinus Torvalds copy = len; 11681da177e4SLinus Torvalds csum = csum_partial(skb->data + offset, copy, csum); 11691da177e4SLinus Torvalds if ((len -= copy) == 0) 11701da177e4SLinus Torvalds return csum; 11711da177e4SLinus Torvalds offset += copy; 11721da177e4SLinus Torvalds pos = copy; 11731da177e4SLinus Torvalds } 11741da177e4SLinus Torvalds 11751da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 11761da177e4SLinus Torvalds int end; 11771da177e4SLinus Torvalds 11781da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 11791da177e4SLinus Torvalds 11801da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 11811da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 11821da177e4SLinus Torvalds unsigned int csum2; 11831da177e4SLinus Torvalds u8 *vaddr; 11841da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 11851da177e4SLinus Torvalds 11861da177e4SLinus Torvalds if (copy > len) 11871da177e4SLinus Torvalds copy = len; 11881da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 11891da177e4SLinus Torvalds csum2 = csum_partial(vaddr + frag->page_offset + 11901da177e4SLinus Torvalds offset - start, copy, 0); 11911da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 11921da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 11931da177e4SLinus Torvalds if (!(len -= copy)) 11941da177e4SLinus Torvalds return csum; 11951da177e4SLinus Torvalds offset += copy; 11961da177e4SLinus Torvalds pos += copy; 11971da177e4SLinus Torvalds } 11981da177e4SLinus Torvalds start = end; 11991da177e4SLinus Torvalds } 12001da177e4SLinus Torvalds 12011da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 12021da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 12031da177e4SLinus Torvalds 12041da177e4SLinus Torvalds for (; list; list = list->next) { 12051da177e4SLinus Torvalds int end; 12061da177e4SLinus Torvalds 12071da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 12081da177e4SLinus Torvalds 12091da177e4SLinus Torvalds end = start + list->len; 12101da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12111da177e4SLinus Torvalds unsigned int csum2; 12121da177e4SLinus Torvalds if (copy > len) 12131da177e4SLinus Torvalds copy = len; 12141da177e4SLinus Torvalds csum2 = skb_checksum(list, offset - start, 12151da177e4SLinus Torvalds copy, 0); 12161da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 12171da177e4SLinus Torvalds if ((len -= copy) == 0) 12181da177e4SLinus Torvalds return csum; 12191da177e4SLinus Torvalds offset += copy; 12201da177e4SLinus Torvalds pos += copy; 12211da177e4SLinus Torvalds } 12221da177e4SLinus Torvalds start = end; 12231da177e4SLinus Torvalds } 12241da177e4SLinus Torvalds } 122509a62660SKris Katterjohn BUG_ON(len); 12261da177e4SLinus Torvalds 12271da177e4SLinus Torvalds return csum; 12281da177e4SLinus Torvalds } 12291da177e4SLinus Torvalds 12301da177e4SLinus Torvalds /* Both of above in one bottle. */ 12311da177e4SLinus Torvalds 12321da177e4SLinus Torvalds unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 12331da177e4SLinus Torvalds u8 *to, int len, unsigned int csum) 12341da177e4SLinus Torvalds { 12351da177e4SLinus Torvalds int start = skb_headlen(skb); 12361da177e4SLinus Torvalds int i, copy = start - offset; 12371da177e4SLinus Torvalds int pos = 0; 12381da177e4SLinus Torvalds 12391da177e4SLinus Torvalds /* Copy header. */ 12401da177e4SLinus Torvalds if (copy > 0) { 12411da177e4SLinus Torvalds if (copy > len) 12421da177e4SLinus Torvalds copy = len; 12431da177e4SLinus Torvalds csum = csum_partial_copy_nocheck(skb->data + offset, to, 12441da177e4SLinus Torvalds copy, csum); 12451da177e4SLinus Torvalds if ((len -= copy) == 0) 12461da177e4SLinus Torvalds return csum; 12471da177e4SLinus Torvalds offset += copy; 12481da177e4SLinus Torvalds to += copy; 12491da177e4SLinus Torvalds pos = copy; 12501da177e4SLinus Torvalds } 12511da177e4SLinus Torvalds 12521da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 12531da177e4SLinus Torvalds int end; 12541da177e4SLinus Torvalds 12551da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 12561da177e4SLinus Torvalds 12571da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 12581da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12591da177e4SLinus Torvalds unsigned int csum2; 12601da177e4SLinus Torvalds u8 *vaddr; 12611da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 12621da177e4SLinus Torvalds 12631da177e4SLinus Torvalds if (copy > len) 12641da177e4SLinus Torvalds copy = len; 12651da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 12661da177e4SLinus Torvalds csum2 = csum_partial_copy_nocheck(vaddr + 12671da177e4SLinus Torvalds frag->page_offset + 12681da177e4SLinus Torvalds offset - start, to, 12691da177e4SLinus Torvalds copy, 0); 12701da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 12711da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 12721da177e4SLinus Torvalds if (!(len -= copy)) 12731da177e4SLinus Torvalds return csum; 12741da177e4SLinus Torvalds offset += copy; 12751da177e4SLinus Torvalds to += copy; 12761da177e4SLinus Torvalds pos += copy; 12771da177e4SLinus Torvalds } 12781da177e4SLinus Torvalds start = end; 12791da177e4SLinus Torvalds } 12801da177e4SLinus Torvalds 12811da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 12821da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 12831da177e4SLinus Torvalds 12841da177e4SLinus Torvalds for (; list; list = list->next) { 12851da177e4SLinus Torvalds unsigned int csum2; 12861da177e4SLinus Torvalds int end; 12871da177e4SLinus Torvalds 12881da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 12891da177e4SLinus Torvalds 12901da177e4SLinus Torvalds end = start + list->len; 12911da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12921da177e4SLinus Torvalds if (copy > len) 12931da177e4SLinus Torvalds copy = len; 12941da177e4SLinus Torvalds csum2 = skb_copy_and_csum_bits(list, 12951da177e4SLinus Torvalds offset - start, 12961da177e4SLinus Torvalds to, copy, 0); 12971da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 12981da177e4SLinus Torvalds if ((len -= copy) == 0) 12991da177e4SLinus Torvalds return csum; 13001da177e4SLinus Torvalds offset += copy; 13011da177e4SLinus Torvalds to += copy; 13021da177e4SLinus Torvalds pos += copy; 13031da177e4SLinus Torvalds } 13041da177e4SLinus Torvalds start = end; 13051da177e4SLinus Torvalds } 13061da177e4SLinus Torvalds } 130709a62660SKris Katterjohn BUG_ON(len); 13081da177e4SLinus Torvalds return csum; 13091da177e4SLinus Torvalds } 13101da177e4SLinus Torvalds 13111da177e4SLinus Torvalds void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) 13121da177e4SLinus Torvalds { 13131da177e4SLinus Torvalds unsigned int csum; 13141da177e4SLinus Torvalds long csstart; 13151da177e4SLinus Torvalds 13161da177e4SLinus Torvalds if (skb->ip_summed == CHECKSUM_HW) 13171da177e4SLinus Torvalds csstart = skb->h.raw - skb->data; 13181da177e4SLinus Torvalds else 13191da177e4SLinus Torvalds csstart = skb_headlen(skb); 13201da177e4SLinus Torvalds 132109a62660SKris Katterjohn BUG_ON(csstart > skb_headlen(skb)); 13221da177e4SLinus Torvalds 13231da177e4SLinus Torvalds memcpy(to, skb->data, csstart); 13241da177e4SLinus Torvalds 13251da177e4SLinus Torvalds csum = 0; 13261da177e4SLinus Torvalds if (csstart != skb->len) 13271da177e4SLinus Torvalds csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, 13281da177e4SLinus Torvalds skb->len - csstart, 0); 13291da177e4SLinus Torvalds 13301da177e4SLinus Torvalds if (skb->ip_summed == CHECKSUM_HW) { 13311da177e4SLinus Torvalds long csstuff = csstart + skb->csum; 13321da177e4SLinus Torvalds 13331da177e4SLinus Torvalds *((unsigned short *)(to + csstuff)) = csum_fold(csum); 13341da177e4SLinus Torvalds } 13351da177e4SLinus Torvalds } 13361da177e4SLinus Torvalds 13371da177e4SLinus Torvalds /** 13381da177e4SLinus Torvalds * skb_dequeue - remove from the head of the queue 13391da177e4SLinus Torvalds * @list: list to dequeue from 13401da177e4SLinus Torvalds * 13411da177e4SLinus Torvalds * Remove the head of the list. The list lock is taken so the function 13421da177e4SLinus Torvalds * may be used safely with other locking list functions. The head item is 13431da177e4SLinus Torvalds * returned or %NULL if the list is empty. 13441da177e4SLinus Torvalds */ 13451da177e4SLinus Torvalds 13461da177e4SLinus Torvalds struct sk_buff *skb_dequeue(struct sk_buff_head *list) 13471da177e4SLinus Torvalds { 13481da177e4SLinus Torvalds unsigned long flags; 13491da177e4SLinus Torvalds struct sk_buff *result; 13501da177e4SLinus Torvalds 13511da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 13521da177e4SLinus Torvalds result = __skb_dequeue(list); 13531da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 13541da177e4SLinus Torvalds return result; 13551da177e4SLinus Torvalds } 13561da177e4SLinus Torvalds 13571da177e4SLinus Torvalds /** 13581da177e4SLinus Torvalds * skb_dequeue_tail - remove from the tail of the queue 13591da177e4SLinus Torvalds * @list: list to dequeue from 13601da177e4SLinus Torvalds * 13611da177e4SLinus Torvalds * Remove the tail of the list. The list lock is taken so the function 13621da177e4SLinus Torvalds * may be used safely with other locking list functions. The tail item is 13631da177e4SLinus Torvalds * returned or %NULL if the list is empty. 13641da177e4SLinus Torvalds */ 13651da177e4SLinus Torvalds struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) 13661da177e4SLinus Torvalds { 13671da177e4SLinus Torvalds unsigned long flags; 13681da177e4SLinus Torvalds struct sk_buff *result; 13691da177e4SLinus Torvalds 13701da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 13711da177e4SLinus Torvalds result = __skb_dequeue_tail(list); 13721da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 13731da177e4SLinus Torvalds return result; 13741da177e4SLinus Torvalds } 13751da177e4SLinus Torvalds 13761da177e4SLinus Torvalds /** 13771da177e4SLinus Torvalds * skb_queue_purge - empty a list 13781da177e4SLinus Torvalds * @list: list to empty 13791da177e4SLinus Torvalds * 13801da177e4SLinus Torvalds * Delete all buffers on an &sk_buff list. Each buffer is removed from 13811da177e4SLinus Torvalds * the list and one reference dropped. This function takes the list 13821da177e4SLinus Torvalds * lock and is atomic with respect to other list locking functions. 13831da177e4SLinus Torvalds */ 13841da177e4SLinus Torvalds void skb_queue_purge(struct sk_buff_head *list) 13851da177e4SLinus Torvalds { 13861da177e4SLinus Torvalds struct sk_buff *skb; 13871da177e4SLinus Torvalds while ((skb = skb_dequeue(list)) != NULL) 13881da177e4SLinus Torvalds kfree_skb(skb); 13891da177e4SLinus Torvalds } 13901da177e4SLinus Torvalds 13911da177e4SLinus Torvalds /** 13921da177e4SLinus Torvalds * skb_queue_head - queue a buffer at the list head 13931da177e4SLinus Torvalds * @list: list to use 13941da177e4SLinus Torvalds * @newsk: buffer to queue 13951da177e4SLinus Torvalds * 13961da177e4SLinus Torvalds * Queue a buffer at the start of the list. This function takes the 13971da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 13981da177e4SLinus Torvalds * safely. 13991da177e4SLinus Torvalds * 14001da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 14011da177e4SLinus Torvalds */ 14021da177e4SLinus Torvalds void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) 14031da177e4SLinus Torvalds { 14041da177e4SLinus Torvalds unsigned long flags; 14051da177e4SLinus Torvalds 14061da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 14071da177e4SLinus Torvalds __skb_queue_head(list, newsk); 14081da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 14091da177e4SLinus Torvalds } 14101da177e4SLinus Torvalds 14111da177e4SLinus Torvalds /** 14121da177e4SLinus Torvalds * skb_queue_tail - queue a buffer at the list tail 14131da177e4SLinus Torvalds * @list: list to use 14141da177e4SLinus Torvalds * @newsk: buffer to queue 14151da177e4SLinus Torvalds * 14161da177e4SLinus Torvalds * Queue a buffer at the tail of the list. This function takes the 14171da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 14181da177e4SLinus Torvalds * safely. 14191da177e4SLinus Torvalds * 14201da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 14211da177e4SLinus Torvalds */ 14221da177e4SLinus Torvalds void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) 14231da177e4SLinus Torvalds { 14241da177e4SLinus Torvalds unsigned long flags; 14251da177e4SLinus Torvalds 14261da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 14271da177e4SLinus Torvalds __skb_queue_tail(list, newsk); 14281da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 14291da177e4SLinus Torvalds } 14308728b834SDavid S. Miller 14311da177e4SLinus Torvalds /** 14321da177e4SLinus Torvalds * skb_unlink - remove a buffer from a list 14331da177e4SLinus Torvalds * @skb: buffer to remove 14348728b834SDavid S. Miller * @list: list to use 14351da177e4SLinus Torvalds * 14368728b834SDavid S. Miller * Remove a packet from a list. The list locks are taken and this 14378728b834SDavid S. Miller * function is atomic with respect to other list locked calls 14381da177e4SLinus Torvalds * 14398728b834SDavid S. Miller * You must know what list the SKB is on. 14401da177e4SLinus Torvalds */ 14418728b834SDavid S. Miller void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 14421da177e4SLinus Torvalds { 14431da177e4SLinus Torvalds unsigned long flags; 14441da177e4SLinus Torvalds 14451da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 14468728b834SDavid S. Miller __skb_unlink(skb, list); 14471da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 14481da177e4SLinus Torvalds } 14491da177e4SLinus Torvalds 14501da177e4SLinus Torvalds /** 14511da177e4SLinus Torvalds * skb_append - append a buffer 14521da177e4SLinus Torvalds * @old: buffer to insert after 14531da177e4SLinus Torvalds * @newsk: buffer to insert 14548728b834SDavid S. Miller * @list: list to use 14551da177e4SLinus Torvalds * 14561da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 14571da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls. 14581da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 14591da177e4SLinus Torvalds */ 14608728b834SDavid S. Miller void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 14611da177e4SLinus Torvalds { 14621da177e4SLinus Torvalds unsigned long flags; 14631da177e4SLinus Torvalds 14648728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 14658728b834SDavid S. Miller __skb_append(old, newsk, list); 14668728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 14671da177e4SLinus Torvalds } 14681da177e4SLinus Torvalds 14691da177e4SLinus Torvalds 14701da177e4SLinus Torvalds /** 14711da177e4SLinus Torvalds * skb_insert - insert a buffer 14721da177e4SLinus Torvalds * @old: buffer to insert before 14731da177e4SLinus Torvalds * @newsk: buffer to insert 14748728b834SDavid S. Miller * @list: list to use 14751da177e4SLinus Torvalds * 14768728b834SDavid S. Miller * Place a packet before a given packet in a list. The list locks are 14778728b834SDavid S. Miller * taken and this function is atomic with respect to other list locked 14788728b834SDavid S. Miller * calls. 14798728b834SDavid S. Miller * 14801da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 14811da177e4SLinus Torvalds */ 14828728b834SDavid S. Miller void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) 14831da177e4SLinus Torvalds { 14841da177e4SLinus Torvalds unsigned long flags; 14851da177e4SLinus Torvalds 14868728b834SDavid S. Miller spin_lock_irqsave(&list->lock, flags); 14878728b834SDavid S. Miller __skb_insert(newsk, old->prev, old, list); 14888728b834SDavid S. Miller spin_unlock_irqrestore(&list->lock, flags); 14891da177e4SLinus Torvalds } 14901da177e4SLinus Torvalds 14911da177e4SLinus Torvalds #if 0 14921da177e4SLinus Torvalds /* 14931da177e4SLinus Torvalds * Tune the memory allocator for a new MTU size. 14941da177e4SLinus Torvalds */ 14951da177e4SLinus Torvalds void skb_add_mtu(int mtu) 14961da177e4SLinus Torvalds { 14971da177e4SLinus Torvalds /* Must match allocation in alloc_skb */ 14981da177e4SLinus Torvalds mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info); 14991da177e4SLinus Torvalds 15001da177e4SLinus Torvalds kmem_add_cache_size(mtu); 15011da177e4SLinus Torvalds } 15021da177e4SLinus Torvalds #endif 15031da177e4SLinus Torvalds 15041da177e4SLinus Torvalds static inline void skb_split_inside_header(struct sk_buff *skb, 15051da177e4SLinus Torvalds struct sk_buff* skb1, 15061da177e4SLinus Torvalds const u32 len, const int pos) 15071da177e4SLinus Torvalds { 15081da177e4SLinus Torvalds int i; 15091da177e4SLinus Torvalds 15101da177e4SLinus Torvalds memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len); 15111da177e4SLinus Torvalds 15121da177e4SLinus Torvalds /* And move data appendix as is. */ 15131da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 15141da177e4SLinus Torvalds skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; 15151da177e4SLinus Torvalds 15161da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; 15171da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 15181da177e4SLinus Torvalds skb1->data_len = skb->data_len; 15191da177e4SLinus Torvalds skb1->len += skb1->data_len; 15201da177e4SLinus Torvalds skb->data_len = 0; 15211da177e4SLinus Torvalds skb->len = len; 15221da177e4SLinus Torvalds skb->tail = skb->data + len; 15231da177e4SLinus Torvalds } 15241da177e4SLinus Torvalds 15251da177e4SLinus Torvalds static inline void skb_split_no_header(struct sk_buff *skb, 15261da177e4SLinus Torvalds struct sk_buff* skb1, 15271da177e4SLinus Torvalds const u32 len, int pos) 15281da177e4SLinus Torvalds { 15291da177e4SLinus Torvalds int i, k = 0; 15301da177e4SLinus Torvalds const int nfrags = skb_shinfo(skb)->nr_frags; 15311da177e4SLinus Torvalds 15321da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 15331da177e4SLinus Torvalds skb1->len = skb1->data_len = skb->len - len; 15341da177e4SLinus Torvalds skb->len = len; 15351da177e4SLinus Torvalds skb->data_len = len - pos; 15361da177e4SLinus Torvalds 15371da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 15381da177e4SLinus Torvalds int size = skb_shinfo(skb)->frags[i].size; 15391da177e4SLinus Torvalds 15401da177e4SLinus Torvalds if (pos + size > len) { 15411da177e4SLinus Torvalds skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; 15421da177e4SLinus Torvalds 15431da177e4SLinus Torvalds if (pos < len) { 15441da177e4SLinus Torvalds /* Split frag. 15451da177e4SLinus Torvalds * We have two variants in this case: 15461da177e4SLinus Torvalds * 1. Move all the frag to the second 15471da177e4SLinus Torvalds * part, if it is possible. F.e. 15481da177e4SLinus Torvalds * this approach is mandatory for TUX, 15491da177e4SLinus Torvalds * where splitting is expensive. 15501da177e4SLinus Torvalds * 2. Split is accurately. We make this. 15511da177e4SLinus Torvalds */ 15521da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 15531da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].page_offset += len - pos; 15541da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].size -= len - pos; 15551da177e4SLinus Torvalds skb_shinfo(skb)->frags[i].size = len - pos; 15561da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 15571da177e4SLinus Torvalds } 15581da177e4SLinus Torvalds k++; 15591da177e4SLinus Torvalds } else 15601da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 15611da177e4SLinus Torvalds pos += size; 15621da177e4SLinus Torvalds } 15631da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = k; 15641da177e4SLinus Torvalds } 15651da177e4SLinus Torvalds 15661da177e4SLinus Torvalds /** 15671da177e4SLinus Torvalds * skb_split - Split fragmented skb to two parts at length len. 15681da177e4SLinus Torvalds * @skb: the buffer to split 15691da177e4SLinus Torvalds * @skb1: the buffer to receive the second part 15701da177e4SLinus Torvalds * @len: new length for skb 15711da177e4SLinus Torvalds */ 15721da177e4SLinus Torvalds void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) 15731da177e4SLinus Torvalds { 15741da177e4SLinus Torvalds int pos = skb_headlen(skb); 15751da177e4SLinus Torvalds 15761da177e4SLinus Torvalds if (len < pos) /* Split line is inside header. */ 15771da177e4SLinus Torvalds skb_split_inside_header(skb, skb1, len, pos); 15781da177e4SLinus Torvalds else /* Second chunk has no header, nothing to copy. */ 15791da177e4SLinus Torvalds skb_split_no_header(skb, skb1, len, pos); 15801da177e4SLinus Torvalds } 15811da177e4SLinus Torvalds 1582677e90edSThomas Graf /** 1583677e90edSThomas Graf * skb_prepare_seq_read - Prepare a sequential read of skb data 1584677e90edSThomas Graf * @skb: the buffer to read 1585677e90edSThomas Graf * @from: lower offset of data to be read 1586677e90edSThomas Graf * @to: upper offset of data to be read 1587677e90edSThomas Graf * @st: state variable 1588677e90edSThomas Graf * 1589677e90edSThomas Graf * Initializes the specified state variable. Must be called before 1590677e90edSThomas Graf * invoking skb_seq_read() for the first time. 1591677e90edSThomas Graf */ 1592677e90edSThomas Graf void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 1593677e90edSThomas Graf unsigned int to, struct skb_seq_state *st) 1594677e90edSThomas Graf { 1595677e90edSThomas Graf st->lower_offset = from; 1596677e90edSThomas Graf st->upper_offset = to; 1597677e90edSThomas Graf st->root_skb = st->cur_skb = skb; 1598677e90edSThomas Graf st->frag_idx = st->stepped_offset = 0; 1599677e90edSThomas Graf st->frag_data = NULL; 1600677e90edSThomas Graf } 1601677e90edSThomas Graf 1602677e90edSThomas Graf /** 1603677e90edSThomas Graf * skb_seq_read - Sequentially read skb data 1604677e90edSThomas Graf * @consumed: number of bytes consumed by the caller so far 1605677e90edSThomas Graf * @data: destination pointer for data to be returned 1606677e90edSThomas Graf * @st: state variable 1607677e90edSThomas Graf * 1608677e90edSThomas Graf * Reads a block of skb data at &consumed relative to the 1609677e90edSThomas Graf * lower offset specified to skb_prepare_seq_read(). Assigns 1610677e90edSThomas Graf * the head of the data block to &data and returns the length 1611677e90edSThomas Graf * of the block or 0 if the end of the skb data or the upper 1612677e90edSThomas Graf * offset has been reached. 1613677e90edSThomas Graf * 1614677e90edSThomas Graf * The caller is not required to consume all of the data 1615677e90edSThomas Graf * returned, i.e. &consumed is typically set to the number 1616677e90edSThomas Graf * of bytes already consumed and the next call to 1617677e90edSThomas Graf * skb_seq_read() will return the remaining part of the block. 1618677e90edSThomas Graf * 1619677e90edSThomas Graf * Note: The size of each block of data returned can be arbitary, 1620677e90edSThomas Graf * this limitation is the cost for zerocopy seqeuental 1621677e90edSThomas Graf * reads of potentially non linear data. 1622677e90edSThomas Graf * 1623677e90edSThomas Graf * Note: Fragment lists within fragments are not implemented 1624677e90edSThomas Graf * at the moment, state->root_skb could be replaced with 1625677e90edSThomas Graf * a stack for this purpose. 1626677e90edSThomas Graf */ 1627677e90edSThomas Graf unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 1628677e90edSThomas Graf struct skb_seq_state *st) 1629677e90edSThomas Graf { 1630677e90edSThomas Graf unsigned int block_limit, abs_offset = consumed + st->lower_offset; 1631677e90edSThomas Graf skb_frag_t *frag; 1632677e90edSThomas Graf 1633677e90edSThomas Graf if (unlikely(abs_offset >= st->upper_offset)) 1634677e90edSThomas Graf return 0; 1635677e90edSThomas Graf 1636677e90edSThomas Graf next_skb: 1637677e90edSThomas Graf block_limit = skb_headlen(st->cur_skb); 1638677e90edSThomas Graf 1639677e90edSThomas Graf if (abs_offset < block_limit) { 1640677e90edSThomas Graf *data = st->cur_skb->data + abs_offset; 1641677e90edSThomas Graf return block_limit - abs_offset; 1642677e90edSThomas Graf } 1643677e90edSThomas Graf 1644677e90edSThomas Graf if (st->frag_idx == 0 && !st->frag_data) 1645677e90edSThomas Graf st->stepped_offset += skb_headlen(st->cur_skb); 1646677e90edSThomas Graf 1647677e90edSThomas Graf while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { 1648677e90edSThomas Graf frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; 1649677e90edSThomas Graf block_limit = frag->size + st->stepped_offset; 1650677e90edSThomas Graf 1651677e90edSThomas Graf if (abs_offset < block_limit) { 1652677e90edSThomas Graf if (!st->frag_data) 1653677e90edSThomas Graf st->frag_data = kmap_skb_frag(frag); 1654677e90edSThomas Graf 1655677e90edSThomas Graf *data = (u8 *) st->frag_data + frag->page_offset + 1656677e90edSThomas Graf (abs_offset - st->stepped_offset); 1657677e90edSThomas Graf 1658677e90edSThomas Graf return block_limit - abs_offset; 1659677e90edSThomas Graf } 1660677e90edSThomas Graf 1661677e90edSThomas Graf if (st->frag_data) { 1662677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 1663677e90edSThomas Graf st->frag_data = NULL; 1664677e90edSThomas Graf } 1665677e90edSThomas Graf 1666677e90edSThomas Graf st->frag_idx++; 1667677e90edSThomas Graf st->stepped_offset += frag->size; 1668677e90edSThomas Graf } 1669677e90edSThomas Graf 1670677e90edSThomas Graf if (st->cur_skb->next) { 1671677e90edSThomas Graf st->cur_skb = st->cur_skb->next; 1672677e90edSThomas Graf st->frag_idx = 0; 1673677e90edSThomas Graf goto next_skb; 1674677e90edSThomas Graf } else if (st->root_skb == st->cur_skb && 1675677e90edSThomas Graf skb_shinfo(st->root_skb)->frag_list) { 1676677e90edSThomas Graf st->cur_skb = skb_shinfo(st->root_skb)->frag_list; 1677677e90edSThomas Graf goto next_skb; 1678677e90edSThomas Graf } 1679677e90edSThomas Graf 1680677e90edSThomas Graf return 0; 1681677e90edSThomas Graf } 1682677e90edSThomas Graf 1683677e90edSThomas Graf /** 1684677e90edSThomas Graf * skb_abort_seq_read - Abort a sequential read of skb data 1685677e90edSThomas Graf * @st: state variable 1686677e90edSThomas Graf * 1687677e90edSThomas Graf * Must be called if skb_seq_read() was not called until it 1688677e90edSThomas Graf * returned 0. 1689677e90edSThomas Graf */ 1690677e90edSThomas Graf void skb_abort_seq_read(struct skb_seq_state *st) 1691677e90edSThomas Graf { 1692677e90edSThomas Graf if (st->frag_data) 1693677e90edSThomas Graf kunmap_skb_frag(st->frag_data); 1694677e90edSThomas Graf } 1695677e90edSThomas Graf 16963fc7e8a6SThomas Graf #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) 16973fc7e8a6SThomas Graf 16983fc7e8a6SThomas Graf static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, 16993fc7e8a6SThomas Graf struct ts_config *conf, 17003fc7e8a6SThomas Graf struct ts_state *state) 17013fc7e8a6SThomas Graf { 17023fc7e8a6SThomas Graf return skb_seq_read(offset, text, TS_SKB_CB(state)); 17033fc7e8a6SThomas Graf } 17043fc7e8a6SThomas Graf 17053fc7e8a6SThomas Graf static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) 17063fc7e8a6SThomas Graf { 17073fc7e8a6SThomas Graf skb_abort_seq_read(TS_SKB_CB(state)); 17083fc7e8a6SThomas Graf } 17093fc7e8a6SThomas Graf 17103fc7e8a6SThomas Graf /** 17113fc7e8a6SThomas Graf * skb_find_text - Find a text pattern in skb data 17123fc7e8a6SThomas Graf * @skb: the buffer to look in 17133fc7e8a6SThomas Graf * @from: search offset 17143fc7e8a6SThomas Graf * @to: search limit 17153fc7e8a6SThomas Graf * @config: textsearch configuration 17163fc7e8a6SThomas Graf * @state: uninitialized textsearch state variable 17173fc7e8a6SThomas Graf * 17183fc7e8a6SThomas Graf * Finds a pattern in the skb data according to the specified 17193fc7e8a6SThomas Graf * textsearch configuration. Use textsearch_next() to retrieve 17203fc7e8a6SThomas Graf * subsequent occurrences of the pattern. Returns the offset 17213fc7e8a6SThomas Graf * to the first occurrence or UINT_MAX if no match was found. 17223fc7e8a6SThomas Graf */ 17233fc7e8a6SThomas Graf unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 17243fc7e8a6SThomas Graf unsigned int to, struct ts_config *config, 17253fc7e8a6SThomas Graf struct ts_state *state) 17263fc7e8a6SThomas Graf { 17273fc7e8a6SThomas Graf config->get_next_block = skb_ts_get_next_block; 17283fc7e8a6SThomas Graf config->finish = skb_ts_finish; 17293fc7e8a6SThomas Graf 17303fc7e8a6SThomas Graf skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); 17313fc7e8a6SThomas Graf 17323fc7e8a6SThomas Graf return textsearch_find(config, state); 17333fc7e8a6SThomas Graf } 17343fc7e8a6SThomas Graf 1735e89e9cf5SAnanda Raju /** 1736e89e9cf5SAnanda Raju * skb_append_datato_frags: - append the user data to a skb 1737e89e9cf5SAnanda Raju * @sk: sock structure 1738e89e9cf5SAnanda Raju * @skb: skb structure to be appened with user data. 1739e89e9cf5SAnanda Raju * @getfrag: call back function to be used for getting the user data 1740e89e9cf5SAnanda Raju * @from: pointer to user message iov 1741e89e9cf5SAnanda Raju * @length: length of the iov message 1742e89e9cf5SAnanda Raju * 1743e89e9cf5SAnanda Raju * Description: This procedure append the user data in the fragment part 1744e89e9cf5SAnanda Raju * of the skb if any page alloc fails user this procedure returns -ENOMEM 1745e89e9cf5SAnanda Raju */ 1746e89e9cf5SAnanda Raju int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, 1747dab9630fSMartin Waitz int (*getfrag)(void *from, char *to, int offset, 1748e89e9cf5SAnanda Raju int len, int odd, struct sk_buff *skb), 1749e89e9cf5SAnanda Raju void *from, int length) 1750e89e9cf5SAnanda Raju { 1751e89e9cf5SAnanda Raju int frg_cnt = 0; 1752e89e9cf5SAnanda Raju skb_frag_t *frag = NULL; 1753e89e9cf5SAnanda Raju struct page *page = NULL; 1754e89e9cf5SAnanda Raju int copy, left; 1755e89e9cf5SAnanda Raju int offset = 0; 1756e89e9cf5SAnanda Raju int ret; 1757e89e9cf5SAnanda Raju 1758e89e9cf5SAnanda Raju do { 1759e89e9cf5SAnanda Raju /* Return error if we don't have space for new frag */ 1760e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 1761e89e9cf5SAnanda Raju if (frg_cnt >= MAX_SKB_FRAGS) 1762e89e9cf5SAnanda Raju return -EFAULT; 1763e89e9cf5SAnanda Raju 1764e89e9cf5SAnanda Raju /* allocate a new page for next frag */ 1765e89e9cf5SAnanda Raju page = alloc_pages(sk->sk_allocation, 0); 1766e89e9cf5SAnanda Raju 1767e89e9cf5SAnanda Raju /* If alloc_page fails just return failure and caller will 1768e89e9cf5SAnanda Raju * free previous allocated pages by doing kfree_skb() 1769e89e9cf5SAnanda Raju */ 1770e89e9cf5SAnanda Raju if (page == NULL) 1771e89e9cf5SAnanda Raju return -ENOMEM; 1772e89e9cf5SAnanda Raju 1773e89e9cf5SAnanda Raju /* initialize the next frag */ 1774e89e9cf5SAnanda Raju sk->sk_sndmsg_page = page; 1775e89e9cf5SAnanda Raju sk->sk_sndmsg_off = 0; 1776e89e9cf5SAnanda Raju skb_fill_page_desc(skb, frg_cnt, page, 0, 0); 1777e89e9cf5SAnanda Raju skb->truesize += PAGE_SIZE; 1778e89e9cf5SAnanda Raju atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); 1779e89e9cf5SAnanda Raju 1780e89e9cf5SAnanda Raju /* get the new initialized frag */ 1781e89e9cf5SAnanda Raju frg_cnt = skb_shinfo(skb)->nr_frags; 1782e89e9cf5SAnanda Raju frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; 1783e89e9cf5SAnanda Raju 1784e89e9cf5SAnanda Raju /* copy the user data to page */ 1785e89e9cf5SAnanda Raju left = PAGE_SIZE - frag->page_offset; 1786e89e9cf5SAnanda Raju copy = (length > left)? left : length; 1787e89e9cf5SAnanda Raju 1788e89e9cf5SAnanda Raju ret = getfrag(from, (page_address(frag->page) + 1789e89e9cf5SAnanda Raju frag->page_offset + frag->size), 1790e89e9cf5SAnanda Raju offset, copy, 0, skb); 1791e89e9cf5SAnanda Raju if (ret < 0) 1792e89e9cf5SAnanda Raju return -EFAULT; 1793e89e9cf5SAnanda Raju 1794e89e9cf5SAnanda Raju /* copy was successful so update the size parameters */ 1795e89e9cf5SAnanda Raju sk->sk_sndmsg_off += copy; 1796e89e9cf5SAnanda Raju frag->size += copy; 1797e89e9cf5SAnanda Raju skb->len += copy; 1798e89e9cf5SAnanda Raju skb->data_len += copy; 1799e89e9cf5SAnanda Raju offset += copy; 1800e89e9cf5SAnanda Raju length -= copy; 1801e89e9cf5SAnanda Raju 1802e89e9cf5SAnanda Raju } while (length > 0); 1803e89e9cf5SAnanda Raju 1804e89e9cf5SAnanda Raju return 0; 1805e89e9cf5SAnanda Raju } 1806e89e9cf5SAnanda Raju 1807cbb042f9SHerbert Xu /** 1808cbb042f9SHerbert Xu * skb_pull_rcsum - pull skb and update receive checksum 1809cbb042f9SHerbert Xu * @skb: buffer to update 1810cbb042f9SHerbert Xu * @start: start of data before pull 1811cbb042f9SHerbert Xu * @len: length of data pulled 1812cbb042f9SHerbert Xu * 1813cbb042f9SHerbert Xu * This function performs an skb_pull on the packet and updates 1814cbb042f9SHerbert Xu * update the CHECKSUM_HW checksum. It should be used on receive 1815cbb042f9SHerbert Xu * path processing instead of skb_pull unless you know that the 1816cbb042f9SHerbert Xu * checksum difference is zero (e.g., a valid IP header) or you 1817cbb042f9SHerbert Xu * are setting ip_summed to CHECKSUM_NONE. 1818cbb042f9SHerbert Xu */ 1819cbb042f9SHerbert Xu unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) 1820cbb042f9SHerbert Xu { 1821cbb042f9SHerbert Xu BUG_ON(len > skb->len); 1822cbb042f9SHerbert Xu skb->len -= len; 1823cbb042f9SHerbert Xu BUG_ON(skb->len < skb->data_len); 1824cbb042f9SHerbert Xu skb_postpull_rcsum(skb, skb->data, len); 1825cbb042f9SHerbert Xu return skb->data += len; 1826cbb042f9SHerbert Xu } 1827cbb042f9SHerbert Xu 1828f94691acSArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(skb_pull_rcsum); 1829f94691acSArnaldo Carvalho de Melo 18301da177e4SLinus Torvalds void __init skb_init(void) 18311da177e4SLinus Torvalds { 18321da177e4SLinus Torvalds skbuff_head_cache = kmem_cache_create("skbuff_head_cache", 18331da177e4SLinus Torvalds sizeof(struct sk_buff), 18341da177e4SLinus Torvalds 0, 18351da177e4SLinus Torvalds SLAB_HWCACHE_ALIGN, 18361da177e4SLinus Torvalds NULL, NULL); 18371da177e4SLinus Torvalds if (!skbuff_head_cache) 18381da177e4SLinus Torvalds panic("cannot create skbuff cache"); 1839d179cd12SDavid S. Miller 1840d179cd12SDavid S. Miller skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", 1841d179cd12SDavid S. Miller (2*sizeof(struct sk_buff)) + 1842d179cd12SDavid S. Miller sizeof(atomic_t), 1843d179cd12SDavid S. Miller 0, 1844d179cd12SDavid S. Miller SLAB_HWCACHE_ALIGN, 1845d179cd12SDavid S. Miller NULL, NULL); 1846d179cd12SDavid S. Miller if (!skbuff_fclone_cache) 1847d179cd12SDavid S. Miller panic("cannot create skbuff cache"); 18481da177e4SLinus Torvalds } 18491da177e4SLinus Torvalds 18501da177e4SLinus Torvalds EXPORT_SYMBOL(___pskb_trim); 18511da177e4SLinus Torvalds EXPORT_SYMBOL(__kfree_skb); 1852231d06aeSJörn Engel EXPORT_SYMBOL(kfree_skb); 18531da177e4SLinus Torvalds EXPORT_SYMBOL(__pskb_pull_tail); 1854d179cd12SDavid S. Miller EXPORT_SYMBOL(__alloc_skb); 18551da177e4SLinus Torvalds EXPORT_SYMBOL(pskb_copy); 18561da177e4SLinus Torvalds EXPORT_SYMBOL(pskb_expand_head); 18571da177e4SLinus Torvalds EXPORT_SYMBOL(skb_checksum); 18581da177e4SLinus Torvalds EXPORT_SYMBOL(skb_clone); 18591da177e4SLinus Torvalds EXPORT_SYMBOL(skb_clone_fraglist); 18601da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy); 18611da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_and_csum_bits); 18621da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_and_csum_dev); 18631da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_bits); 18641da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_expand); 18651da177e4SLinus Torvalds EXPORT_SYMBOL(skb_over_panic); 18661da177e4SLinus Torvalds EXPORT_SYMBOL(skb_pad); 18671da177e4SLinus Torvalds EXPORT_SYMBOL(skb_realloc_headroom); 18681da177e4SLinus Torvalds EXPORT_SYMBOL(skb_under_panic); 18691da177e4SLinus Torvalds EXPORT_SYMBOL(skb_dequeue); 18701da177e4SLinus Torvalds EXPORT_SYMBOL(skb_dequeue_tail); 18711da177e4SLinus Torvalds EXPORT_SYMBOL(skb_insert); 18721da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_purge); 18731da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_head); 18741da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_tail); 18751da177e4SLinus Torvalds EXPORT_SYMBOL(skb_unlink); 18761da177e4SLinus Torvalds EXPORT_SYMBOL(skb_append); 18771da177e4SLinus Torvalds EXPORT_SYMBOL(skb_split); 1878677e90edSThomas Graf EXPORT_SYMBOL(skb_prepare_seq_read); 1879677e90edSThomas Graf EXPORT_SYMBOL(skb_seq_read); 1880677e90edSThomas Graf EXPORT_SYMBOL(skb_abort_seq_read); 18813fc7e8a6SThomas Graf EXPORT_SYMBOL(skb_find_text); 1882e89e9cf5SAnanda Raju EXPORT_SYMBOL(skb_append_datato_frags); 1883