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 711da177e4SLinus Torvalds static kmem_cache_t *skbuff_head_cache; 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds /* 741da177e4SLinus Torvalds * Keep out-of-line to prevent kernel bloat. 751da177e4SLinus Torvalds * __builtin_return_address is not used because it is not always 761da177e4SLinus Torvalds * reliable. 771da177e4SLinus Torvalds */ 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds /** 801da177e4SLinus Torvalds * skb_over_panic - private function 811da177e4SLinus Torvalds * @skb: buffer 821da177e4SLinus Torvalds * @sz: size 831da177e4SLinus Torvalds * @here: address 841da177e4SLinus Torvalds * 851da177e4SLinus Torvalds * Out of line support code for skb_put(). Not user callable. 861da177e4SLinus Torvalds */ 871da177e4SLinus Torvalds void skb_over_panic(struct sk_buff *skb, int sz, void *here) 881da177e4SLinus Torvalds { 891da177e4SLinus Torvalds printk(KERN_INFO "skput:over: %p:%d put:%d dev:%s", 901da177e4SLinus Torvalds here, skb->len, sz, skb->dev ? skb->dev->name : "<NULL>"); 911da177e4SLinus Torvalds BUG(); 921da177e4SLinus Torvalds } 931da177e4SLinus Torvalds 941da177e4SLinus Torvalds /** 951da177e4SLinus Torvalds * skb_under_panic - private function 961da177e4SLinus Torvalds * @skb: buffer 971da177e4SLinus Torvalds * @sz: size 981da177e4SLinus Torvalds * @here: address 991da177e4SLinus Torvalds * 1001da177e4SLinus Torvalds * Out of line support code for skb_push(). Not user callable. 1011da177e4SLinus Torvalds */ 1021da177e4SLinus Torvalds 1031da177e4SLinus Torvalds void skb_under_panic(struct sk_buff *skb, int sz, void *here) 1041da177e4SLinus Torvalds { 1051da177e4SLinus Torvalds printk(KERN_INFO "skput:under: %p:%d put:%d dev:%s", 1061da177e4SLinus Torvalds here, skb->len, sz, skb->dev ? skb->dev->name : "<NULL>"); 1071da177e4SLinus Torvalds BUG(); 1081da177e4SLinus Torvalds } 1091da177e4SLinus Torvalds 1101da177e4SLinus Torvalds /* Allocate a new skbuff. We do this ourselves so we can fill in a few 1111da177e4SLinus Torvalds * 'private' fields and also do memory statistics to find all the 1121da177e4SLinus Torvalds * [BEEP] leaks. 1131da177e4SLinus Torvalds * 1141da177e4SLinus Torvalds */ 1151da177e4SLinus Torvalds 1161da177e4SLinus Torvalds /** 1171da177e4SLinus Torvalds * alloc_skb - allocate a network buffer 1181da177e4SLinus Torvalds * @size: size to allocate 1191da177e4SLinus Torvalds * @gfp_mask: allocation mask 1201da177e4SLinus Torvalds * 1211da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and a 1221da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 1231da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 1241da177e4SLinus Torvalds * 1251da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1261da177e4SLinus Torvalds * %GFP_ATOMIC. 1271da177e4SLinus Torvalds */ 1281da177e4SLinus Torvalds struct sk_buff *alloc_skb(unsigned int size, int gfp_mask) 1291da177e4SLinus Torvalds { 1301da177e4SLinus Torvalds struct sk_buff *skb; 1311da177e4SLinus Torvalds u8 *data; 1321da177e4SLinus Torvalds 1331da177e4SLinus Torvalds /* Get the HEAD */ 1341da177e4SLinus Torvalds skb = kmem_cache_alloc(skbuff_head_cache, 1351da177e4SLinus Torvalds gfp_mask & ~__GFP_DMA); 1361da177e4SLinus Torvalds if (!skb) 1371da177e4SLinus Torvalds goto out; 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds /* Get the DATA. Size must match skb_add_mtu(). */ 1401da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 1411da177e4SLinus Torvalds data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); 1421da177e4SLinus Torvalds if (!data) 1431da177e4SLinus Torvalds goto nodata; 1441da177e4SLinus Torvalds 1451da177e4SLinus Torvalds memset(skb, 0, offsetof(struct sk_buff, truesize)); 1461da177e4SLinus Torvalds skb->truesize = size + sizeof(struct sk_buff); 1471da177e4SLinus Torvalds atomic_set(&skb->users, 1); 1481da177e4SLinus Torvalds skb->head = data; 1491da177e4SLinus Torvalds skb->data = data; 1501da177e4SLinus Torvalds skb->tail = data; 1511da177e4SLinus Torvalds skb->end = data + size; 1521da177e4SLinus Torvalds 1531da177e4SLinus Torvalds atomic_set(&(skb_shinfo(skb)->dataref), 1); 1541da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 1551da177e4SLinus Torvalds skb_shinfo(skb)->tso_size = 0; 1561da177e4SLinus Torvalds skb_shinfo(skb)->tso_segs = 0; 1571da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = NULL; 1581da177e4SLinus Torvalds out: 1591da177e4SLinus Torvalds return skb; 1601da177e4SLinus Torvalds nodata: 1611da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 1621da177e4SLinus Torvalds skb = NULL; 1631da177e4SLinus Torvalds goto out; 1641da177e4SLinus Torvalds } 1651da177e4SLinus Torvalds 1661da177e4SLinus Torvalds /** 1671da177e4SLinus Torvalds * alloc_skb_from_cache - allocate a network buffer 1681da177e4SLinus Torvalds * @cp: kmem_cache from which to allocate the data area 1691da177e4SLinus Torvalds * (object size must be big enough for @size bytes + skb overheads) 1701da177e4SLinus Torvalds * @size: size to allocate 1711da177e4SLinus Torvalds * @gfp_mask: allocation mask 1721da177e4SLinus Torvalds * 1731da177e4SLinus Torvalds * Allocate a new &sk_buff. The returned buffer has no headroom and 1741da177e4SLinus Torvalds * tail room of size bytes. The object has a reference count of one. 1751da177e4SLinus Torvalds * The return is the buffer. On a failure the return is %NULL. 1761da177e4SLinus Torvalds * 1771da177e4SLinus Torvalds * Buffers may only be allocated from interrupts using a @gfp_mask of 1781da177e4SLinus Torvalds * %GFP_ATOMIC. 1791da177e4SLinus Torvalds */ 1801da177e4SLinus Torvalds struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp, 1811da177e4SLinus Torvalds unsigned int size, int gfp_mask) 1821da177e4SLinus Torvalds { 1831da177e4SLinus Torvalds struct sk_buff *skb; 1841da177e4SLinus Torvalds u8 *data; 1851da177e4SLinus Torvalds 1861da177e4SLinus Torvalds /* Get the HEAD */ 1871da177e4SLinus Torvalds skb = kmem_cache_alloc(skbuff_head_cache, 1881da177e4SLinus Torvalds gfp_mask & ~__GFP_DMA); 1891da177e4SLinus Torvalds if (!skb) 1901da177e4SLinus Torvalds goto out; 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds /* Get the DATA. */ 1931da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 1941da177e4SLinus Torvalds data = kmem_cache_alloc(cp, gfp_mask); 1951da177e4SLinus Torvalds if (!data) 1961da177e4SLinus Torvalds goto nodata; 1971da177e4SLinus Torvalds 1981da177e4SLinus Torvalds memset(skb, 0, offsetof(struct sk_buff, truesize)); 1991da177e4SLinus Torvalds skb->truesize = size + sizeof(struct sk_buff); 2001da177e4SLinus Torvalds atomic_set(&skb->users, 1); 2011da177e4SLinus Torvalds skb->head = data; 2021da177e4SLinus Torvalds skb->data = data; 2031da177e4SLinus Torvalds skb->tail = data; 2041da177e4SLinus Torvalds skb->end = data + size; 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds atomic_set(&(skb_shinfo(skb)->dataref), 1); 2071da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 2081da177e4SLinus Torvalds skb_shinfo(skb)->tso_size = 0; 2091da177e4SLinus Torvalds skb_shinfo(skb)->tso_segs = 0; 2101da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = NULL; 2111da177e4SLinus Torvalds out: 2121da177e4SLinus Torvalds return skb; 2131da177e4SLinus Torvalds nodata: 2141da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 2151da177e4SLinus Torvalds skb = NULL; 2161da177e4SLinus Torvalds goto out; 2171da177e4SLinus Torvalds } 2181da177e4SLinus Torvalds 2191da177e4SLinus Torvalds 2201da177e4SLinus Torvalds static void skb_drop_fraglist(struct sk_buff *skb) 2211da177e4SLinus Torvalds { 2221da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 2231da177e4SLinus Torvalds 2241da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = NULL; 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds do { 2271da177e4SLinus Torvalds struct sk_buff *this = list; 2281da177e4SLinus Torvalds list = list->next; 2291da177e4SLinus Torvalds kfree_skb(this); 2301da177e4SLinus Torvalds } while (list); 2311da177e4SLinus Torvalds } 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds static void skb_clone_fraglist(struct sk_buff *skb) 2341da177e4SLinus Torvalds { 2351da177e4SLinus Torvalds struct sk_buff *list; 2361da177e4SLinus Torvalds 2371da177e4SLinus Torvalds for (list = skb_shinfo(skb)->frag_list; list; list = list->next) 2381da177e4SLinus Torvalds skb_get(list); 2391da177e4SLinus Torvalds } 2401da177e4SLinus Torvalds 2411da177e4SLinus Torvalds void skb_release_data(struct sk_buff *skb) 2421da177e4SLinus Torvalds { 2431da177e4SLinus Torvalds if (!skb->cloned || 2441da177e4SLinus Torvalds !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, 2451da177e4SLinus Torvalds &skb_shinfo(skb)->dataref)) { 2461da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 2471da177e4SLinus Torvalds int i; 2481da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 2491da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 2501da177e4SLinus Torvalds } 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 2531da177e4SLinus Torvalds skb_drop_fraglist(skb); 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds kfree(skb->head); 2561da177e4SLinus Torvalds } 2571da177e4SLinus Torvalds } 2581da177e4SLinus Torvalds 2591da177e4SLinus Torvalds /* 2601da177e4SLinus Torvalds * Free an skbuff by memory without cleaning the state. 2611da177e4SLinus Torvalds */ 2621da177e4SLinus Torvalds void kfree_skbmem(struct sk_buff *skb) 2631da177e4SLinus Torvalds { 2641da177e4SLinus Torvalds skb_release_data(skb); 2651da177e4SLinus Torvalds kmem_cache_free(skbuff_head_cache, skb); 2661da177e4SLinus Torvalds } 2671da177e4SLinus Torvalds 2681da177e4SLinus Torvalds /** 2691da177e4SLinus Torvalds * __kfree_skb - private function 2701da177e4SLinus Torvalds * @skb: buffer 2711da177e4SLinus Torvalds * 2721da177e4SLinus Torvalds * Free an sk_buff. Release anything attached to the buffer. 2731da177e4SLinus Torvalds * Clean the state. This is an internal helper function. Users should 2741da177e4SLinus Torvalds * always call kfree_skb 2751da177e4SLinus Torvalds */ 2761da177e4SLinus Torvalds 2771da177e4SLinus Torvalds void __kfree_skb(struct sk_buff *skb) 2781da177e4SLinus Torvalds { 2799c2b3328SStephen Hemminger BUG_ON(skb->list != NULL); 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds dst_release(skb->dst); 2821da177e4SLinus Torvalds #ifdef CONFIG_XFRM 2831da177e4SLinus Torvalds secpath_put(skb->sp); 2841da177e4SLinus Torvalds #endif 2851da177e4SLinus Torvalds if (skb->destructor) { 2869c2b3328SStephen Hemminger WARN_ON(in_irq()); 2871da177e4SLinus Torvalds skb->destructor(skb); 2881da177e4SLinus Torvalds } 2891da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 2901da177e4SLinus Torvalds nf_conntrack_put(skb->nfct); 2911da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 2921da177e4SLinus Torvalds nf_bridge_put(skb->nf_bridge); 2931da177e4SLinus Torvalds #endif 2941da177e4SLinus Torvalds #endif 2951da177e4SLinus Torvalds /* XXX: IS this still necessary? - JHS */ 2961da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 2971da177e4SLinus Torvalds skb->tc_index = 0; 2981da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 2991da177e4SLinus Torvalds skb->tc_verd = 0; 3001da177e4SLinus Torvalds skb->tc_classid = 0; 3011da177e4SLinus Torvalds #endif 3021da177e4SLinus Torvalds #endif 3031da177e4SLinus Torvalds 3041da177e4SLinus Torvalds kfree_skbmem(skb); 3051da177e4SLinus Torvalds } 3061da177e4SLinus Torvalds 3071da177e4SLinus Torvalds /** 3081da177e4SLinus Torvalds * skb_clone - duplicate an sk_buff 3091da177e4SLinus Torvalds * @skb: buffer to clone 3101da177e4SLinus Torvalds * @gfp_mask: allocation priority 3111da177e4SLinus Torvalds * 3121da177e4SLinus Torvalds * Duplicate an &sk_buff. The new one is not owned by a socket. Both 3131da177e4SLinus Torvalds * copies share the same packet data but not structure. The new 3141da177e4SLinus Torvalds * buffer has a reference count of 1. If the allocation fails the 3151da177e4SLinus Torvalds * function returns %NULL otherwise the new buffer is returned. 3161da177e4SLinus Torvalds * 3171da177e4SLinus Torvalds * If this function is called from an interrupt gfp_mask() must be 3181da177e4SLinus Torvalds * %GFP_ATOMIC. 3191da177e4SLinus Torvalds */ 3201da177e4SLinus Torvalds 3211da177e4SLinus Torvalds struct sk_buff *skb_clone(struct sk_buff *skb, int gfp_mask) 3221da177e4SLinus Torvalds { 3231da177e4SLinus Torvalds struct sk_buff *n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds if (!n) 3261da177e4SLinus Torvalds return NULL; 3271da177e4SLinus Torvalds 3281da177e4SLinus Torvalds #define C(x) n->x = skb->x 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds n->next = n->prev = NULL; 3311da177e4SLinus Torvalds n->list = NULL; 3321da177e4SLinus Torvalds n->sk = NULL; 3331da177e4SLinus Torvalds C(stamp); 3341da177e4SLinus Torvalds C(dev); 3351da177e4SLinus Torvalds C(real_dev); 3361da177e4SLinus Torvalds C(h); 3371da177e4SLinus Torvalds C(nh); 3381da177e4SLinus Torvalds C(mac); 3391da177e4SLinus Torvalds C(dst); 3401da177e4SLinus Torvalds dst_clone(skb->dst); 3411da177e4SLinus Torvalds C(sp); 3421da177e4SLinus Torvalds #ifdef CONFIG_INET 3431da177e4SLinus Torvalds secpath_get(skb->sp); 3441da177e4SLinus Torvalds #endif 3451da177e4SLinus Torvalds memcpy(n->cb, skb->cb, sizeof(skb->cb)); 3461da177e4SLinus Torvalds C(len); 3471da177e4SLinus Torvalds C(data_len); 3481da177e4SLinus Torvalds C(csum); 3491da177e4SLinus Torvalds C(local_df); 3501da177e4SLinus Torvalds n->cloned = 1; 3511da177e4SLinus Torvalds n->nohdr = 0; 3521da177e4SLinus Torvalds C(pkt_type); 3531da177e4SLinus Torvalds C(ip_summed); 3541da177e4SLinus Torvalds C(priority); 3551da177e4SLinus Torvalds C(protocol); 3561da177e4SLinus Torvalds C(security); 3571da177e4SLinus Torvalds n->destructor = NULL; 3581da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 3591da177e4SLinus Torvalds C(nfmark); 3601da177e4SLinus Torvalds C(nfcache); 3611da177e4SLinus Torvalds C(nfct); 3621da177e4SLinus Torvalds nf_conntrack_get(skb->nfct); 3631da177e4SLinus Torvalds C(nfctinfo); 3641da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER_DEBUG 3651da177e4SLinus Torvalds C(nf_debug); 3661da177e4SLinus Torvalds #endif 3671da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 3681da177e4SLinus Torvalds C(nf_bridge); 3691da177e4SLinus Torvalds nf_bridge_get(skb->nf_bridge); 3701da177e4SLinus Torvalds #endif 3711da177e4SLinus Torvalds #endif /*CONFIG_NETFILTER*/ 3721da177e4SLinus Torvalds #if defined(CONFIG_HIPPI) 3731da177e4SLinus Torvalds C(private); 3741da177e4SLinus Torvalds #endif 3751da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 3761da177e4SLinus Torvalds C(tc_index); 3771da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 3781da177e4SLinus Torvalds n->tc_verd = SET_TC_VERD(skb->tc_verd,0); 3791da177e4SLinus Torvalds n->tc_verd = CLR_TC_OK2MUNGE(skb->tc_verd); 3801da177e4SLinus Torvalds n->tc_verd = CLR_TC_MUNGED(skb->tc_verd); 3811da177e4SLinus Torvalds C(input_dev); 3821da177e4SLinus Torvalds C(tc_classid); 3831da177e4SLinus Torvalds #endif 3841da177e4SLinus Torvalds 3851da177e4SLinus Torvalds #endif 3861da177e4SLinus Torvalds C(truesize); 3871da177e4SLinus Torvalds atomic_set(&n->users, 1); 3881da177e4SLinus Torvalds C(head); 3891da177e4SLinus Torvalds C(data); 3901da177e4SLinus Torvalds C(tail); 3911da177e4SLinus Torvalds C(end); 3921da177e4SLinus Torvalds 3931da177e4SLinus Torvalds atomic_inc(&(skb_shinfo(skb)->dataref)); 3941da177e4SLinus Torvalds skb->cloned = 1; 3951da177e4SLinus Torvalds 3961da177e4SLinus Torvalds return n; 3971da177e4SLinus Torvalds } 3981da177e4SLinus Torvalds 3991da177e4SLinus Torvalds static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 4001da177e4SLinus Torvalds { 4011da177e4SLinus Torvalds /* 4021da177e4SLinus Torvalds * Shift between the two data areas in bytes 4031da177e4SLinus Torvalds */ 4041da177e4SLinus Torvalds unsigned long offset = new->data - old->data; 4051da177e4SLinus Torvalds 4061da177e4SLinus Torvalds new->list = NULL; 4071da177e4SLinus Torvalds new->sk = NULL; 4081da177e4SLinus Torvalds new->dev = old->dev; 4091da177e4SLinus Torvalds new->real_dev = old->real_dev; 4101da177e4SLinus Torvalds new->priority = old->priority; 4111da177e4SLinus Torvalds new->protocol = old->protocol; 4121da177e4SLinus Torvalds new->dst = dst_clone(old->dst); 4131da177e4SLinus Torvalds #ifdef CONFIG_INET 4141da177e4SLinus Torvalds new->sp = secpath_get(old->sp); 4151da177e4SLinus Torvalds #endif 4161da177e4SLinus Torvalds new->h.raw = old->h.raw + offset; 4171da177e4SLinus Torvalds new->nh.raw = old->nh.raw + offset; 4181da177e4SLinus Torvalds new->mac.raw = old->mac.raw + offset; 4191da177e4SLinus Torvalds memcpy(new->cb, old->cb, sizeof(old->cb)); 4201da177e4SLinus Torvalds new->local_df = old->local_df; 4211da177e4SLinus Torvalds new->pkt_type = old->pkt_type; 4221da177e4SLinus Torvalds new->stamp = old->stamp; 4231da177e4SLinus Torvalds new->destructor = NULL; 4241da177e4SLinus Torvalds new->security = old->security; 4251da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER 4261da177e4SLinus Torvalds new->nfmark = old->nfmark; 4271da177e4SLinus Torvalds new->nfcache = old->nfcache; 4281da177e4SLinus Torvalds new->nfct = old->nfct; 4291da177e4SLinus Torvalds nf_conntrack_get(old->nfct); 4301da177e4SLinus Torvalds new->nfctinfo = old->nfctinfo; 4311da177e4SLinus Torvalds #ifdef CONFIG_NETFILTER_DEBUG 4321da177e4SLinus Torvalds new->nf_debug = old->nf_debug; 4331da177e4SLinus Torvalds #endif 4341da177e4SLinus Torvalds #ifdef CONFIG_BRIDGE_NETFILTER 4351da177e4SLinus Torvalds new->nf_bridge = old->nf_bridge; 4361da177e4SLinus Torvalds nf_bridge_get(old->nf_bridge); 4371da177e4SLinus Torvalds #endif 4381da177e4SLinus Torvalds #endif 4391da177e4SLinus Torvalds #ifdef CONFIG_NET_SCHED 4401da177e4SLinus Torvalds #ifdef CONFIG_NET_CLS_ACT 4411da177e4SLinus Torvalds new->tc_verd = old->tc_verd; 4421da177e4SLinus Torvalds #endif 4431da177e4SLinus Torvalds new->tc_index = old->tc_index; 4441da177e4SLinus Torvalds #endif 4451da177e4SLinus Torvalds atomic_set(&new->users, 1); 4461da177e4SLinus Torvalds skb_shinfo(new)->tso_size = skb_shinfo(old)->tso_size; 4471da177e4SLinus Torvalds skb_shinfo(new)->tso_segs = skb_shinfo(old)->tso_segs; 4481da177e4SLinus Torvalds } 4491da177e4SLinus Torvalds 4501da177e4SLinus Torvalds /** 4511da177e4SLinus Torvalds * skb_copy - create private copy of an sk_buff 4521da177e4SLinus Torvalds * @skb: buffer to copy 4531da177e4SLinus Torvalds * @gfp_mask: allocation priority 4541da177e4SLinus Torvalds * 4551da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data. This is used when the 4561da177e4SLinus Torvalds * caller wishes to modify the data and needs a private copy of the 4571da177e4SLinus Torvalds * data to alter. Returns %NULL on failure or the pointer to the buffer 4581da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 4591da177e4SLinus Torvalds * 4601da177e4SLinus Torvalds * As by-product this function converts non-linear &sk_buff to linear 4611da177e4SLinus Torvalds * one, so that &sk_buff becomes completely private and caller is allowed 4621da177e4SLinus Torvalds * to modify all the data of returned buffer. This means that this 4631da177e4SLinus Torvalds * function is not recommended for use in circumstances when only 4641da177e4SLinus Torvalds * header is going to be modified. Use pskb_copy() instead. 4651da177e4SLinus Torvalds */ 4661da177e4SLinus Torvalds 4671da177e4SLinus Torvalds struct sk_buff *skb_copy(const struct sk_buff *skb, int gfp_mask) 4681da177e4SLinus Torvalds { 4691da177e4SLinus Torvalds int headerlen = skb->data - skb->head; 4701da177e4SLinus Torvalds /* 4711da177e4SLinus Torvalds * Allocate the copy buffer 4721da177e4SLinus Torvalds */ 4731da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len, 4741da177e4SLinus Torvalds gfp_mask); 4751da177e4SLinus Torvalds if (!n) 4761da177e4SLinus Torvalds return NULL; 4771da177e4SLinus Torvalds 4781da177e4SLinus Torvalds /* Set the data pointer */ 4791da177e4SLinus Torvalds skb_reserve(n, headerlen); 4801da177e4SLinus Torvalds /* Set the tail pointer and length */ 4811da177e4SLinus Torvalds skb_put(n, skb->len); 4821da177e4SLinus Torvalds n->csum = skb->csum; 4831da177e4SLinus Torvalds n->ip_summed = skb->ip_summed; 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) 4861da177e4SLinus Torvalds BUG(); 4871da177e4SLinus Torvalds 4881da177e4SLinus Torvalds copy_skb_header(n, skb); 4891da177e4SLinus Torvalds return n; 4901da177e4SLinus Torvalds } 4911da177e4SLinus Torvalds 4921da177e4SLinus Torvalds 4931da177e4SLinus Torvalds /** 4941da177e4SLinus Torvalds * pskb_copy - create copy of an sk_buff with private head. 4951da177e4SLinus Torvalds * @skb: buffer to copy 4961da177e4SLinus Torvalds * @gfp_mask: allocation priority 4971da177e4SLinus Torvalds * 4981da177e4SLinus Torvalds * Make a copy of both an &sk_buff and part of its data, located 4991da177e4SLinus Torvalds * in header. Fragmented data remain shared. This is used when 5001da177e4SLinus Torvalds * the caller wishes to modify only header of &sk_buff and needs 5011da177e4SLinus Torvalds * private copy of the header to alter. Returns %NULL on failure 5021da177e4SLinus Torvalds * or the pointer to the buffer on success. 5031da177e4SLinus Torvalds * The returned buffer has a reference count of 1. 5041da177e4SLinus Torvalds */ 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds struct sk_buff *pskb_copy(struct sk_buff *skb, int gfp_mask) 5071da177e4SLinus Torvalds { 5081da177e4SLinus Torvalds /* 5091da177e4SLinus Torvalds * Allocate the copy buffer 5101da177e4SLinus Torvalds */ 5111da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask); 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds if (!n) 5141da177e4SLinus Torvalds goto out; 5151da177e4SLinus Torvalds 5161da177e4SLinus Torvalds /* Set the data pointer */ 5171da177e4SLinus Torvalds skb_reserve(n, skb->data - skb->head); 5181da177e4SLinus Torvalds /* Set the tail pointer and length */ 5191da177e4SLinus Torvalds skb_put(n, skb_headlen(skb)); 5201da177e4SLinus Torvalds /* Copy the bytes */ 5211da177e4SLinus Torvalds memcpy(n->data, skb->data, n->len); 5221da177e4SLinus Torvalds n->csum = skb->csum; 5231da177e4SLinus Torvalds n->ip_summed = skb->ip_summed; 5241da177e4SLinus Torvalds 5251da177e4SLinus Torvalds n->data_len = skb->data_len; 5261da177e4SLinus Torvalds n->len = skb->len; 5271da177e4SLinus Torvalds 5281da177e4SLinus Torvalds if (skb_shinfo(skb)->nr_frags) { 5291da177e4SLinus Torvalds int i; 5301da177e4SLinus Torvalds 5311da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 5321da177e4SLinus Torvalds skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; 5331da177e4SLinus Torvalds get_page(skb_shinfo(n)->frags[i].page); 5341da177e4SLinus Torvalds } 5351da177e4SLinus Torvalds skb_shinfo(n)->nr_frags = i; 5361da177e4SLinus Torvalds } 5371da177e4SLinus Torvalds 5381da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 5391da177e4SLinus Torvalds skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; 5401da177e4SLinus Torvalds skb_clone_fraglist(n); 5411da177e4SLinus Torvalds } 5421da177e4SLinus Torvalds 5431da177e4SLinus Torvalds copy_skb_header(n, skb); 5441da177e4SLinus Torvalds out: 5451da177e4SLinus Torvalds return n; 5461da177e4SLinus Torvalds } 5471da177e4SLinus Torvalds 5481da177e4SLinus Torvalds /** 5491da177e4SLinus Torvalds * pskb_expand_head - reallocate header of &sk_buff 5501da177e4SLinus Torvalds * @skb: buffer to reallocate 5511da177e4SLinus Torvalds * @nhead: room to add at head 5521da177e4SLinus Torvalds * @ntail: room to add at tail 5531da177e4SLinus Torvalds * @gfp_mask: allocation priority 5541da177e4SLinus Torvalds * 5551da177e4SLinus Torvalds * Expands (or creates identical copy, if &nhead and &ntail are zero) 5561da177e4SLinus Torvalds * header of skb. &sk_buff itself is not changed. &sk_buff MUST have 5571da177e4SLinus Torvalds * reference count of 1. Returns zero in the case of success or error, 5581da177e4SLinus Torvalds * if expansion failed. In the last case, &sk_buff is not changed. 5591da177e4SLinus Torvalds * 5601da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 5611da177e4SLinus Torvalds * reloaded after call to this function. 5621da177e4SLinus Torvalds */ 5631da177e4SLinus Torvalds 5641da177e4SLinus Torvalds int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, int gfp_mask) 5651da177e4SLinus Torvalds { 5661da177e4SLinus Torvalds int i; 5671da177e4SLinus Torvalds u8 *data; 5681da177e4SLinus Torvalds int size = nhead + (skb->end - skb->head) + ntail; 5691da177e4SLinus Torvalds long off; 5701da177e4SLinus Torvalds 5711da177e4SLinus Torvalds if (skb_shared(skb)) 5721da177e4SLinus Torvalds BUG(); 5731da177e4SLinus Torvalds 5741da177e4SLinus Torvalds size = SKB_DATA_ALIGN(size); 5751da177e4SLinus Torvalds 5761da177e4SLinus Torvalds data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); 5771da177e4SLinus Torvalds if (!data) 5781da177e4SLinus Torvalds goto nodata; 5791da177e4SLinus Torvalds 5801da177e4SLinus Torvalds /* Copy only real data... and, alas, header. This should be 5811da177e4SLinus Torvalds * optimized for the cases when header is void. */ 5821da177e4SLinus Torvalds memcpy(data + nhead, skb->head, skb->tail - skb->head); 5831da177e4SLinus Torvalds memcpy(data + size, skb->end, sizeof(struct skb_shared_info)); 5841da177e4SLinus Torvalds 5851da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 5861da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 5871da177e4SLinus Torvalds 5881da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) 5891da177e4SLinus Torvalds skb_clone_fraglist(skb); 5901da177e4SLinus Torvalds 5911da177e4SLinus Torvalds skb_release_data(skb); 5921da177e4SLinus Torvalds 5931da177e4SLinus Torvalds off = (data + nhead) - skb->head; 5941da177e4SLinus Torvalds 5951da177e4SLinus Torvalds skb->head = data; 5961da177e4SLinus Torvalds skb->end = data + size; 5971da177e4SLinus Torvalds skb->data += off; 5981da177e4SLinus Torvalds skb->tail += off; 5991da177e4SLinus Torvalds skb->mac.raw += off; 6001da177e4SLinus Torvalds skb->h.raw += off; 6011da177e4SLinus Torvalds skb->nh.raw += off; 6021da177e4SLinus Torvalds skb->cloned = 0; 6031da177e4SLinus Torvalds skb->nohdr = 0; 6041da177e4SLinus Torvalds atomic_set(&skb_shinfo(skb)->dataref, 1); 6051da177e4SLinus Torvalds return 0; 6061da177e4SLinus Torvalds 6071da177e4SLinus Torvalds nodata: 6081da177e4SLinus Torvalds return -ENOMEM; 6091da177e4SLinus Torvalds } 6101da177e4SLinus Torvalds 6111da177e4SLinus Torvalds /* Make private copy of skb with writable head and some headroom */ 6121da177e4SLinus Torvalds 6131da177e4SLinus Torvalds struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) 6141da177e4SLinus Torvalds { 6151da177e4SLinus Torvalds struct sk_buff *skb2; 6161da177e4SLinus Torvalds int delta = headroom - skb_headroom(skb); 6171da177e4SLinus Torvalds 6181da177e4SLinus Torvalds if (delta <= 0) 6191da177e4SLinus Torvalds skb2 = pskb_copy(skb, GFP_ATOMIC); 6201da177e4SLinus Torvalds else { 6211da177e4SLinus Torvalds skb2 = skb_clone(skb, GFP_ATOMIC); 6221da177e4SLinus Torvalds if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, 6231da177e4SLinus Torvalds GFP_ATOMIC)) { 6241da177e4SLinus Torvalds kfree_skb(skb2); 6251da177e4SLinus Torvalds skb2 = NULL; 6261da177e4SLinus Torvalds } 6271da177e4SLinus Torvalds } 6281da177e4SLinus Torvalds return skb2; 6291da177e4SLinus Torvalds } 6301da177e4SLinus Torvalds 6311da177e4SLinus Torvalds 6321da177e4SLinus Torvalds /** 6331da177e4SLinus Torvalds * skb_copy_expand - copy and expand sk_buff 6341da177e4SLinus Torvalds * @skb: buffer to copy 6351da177e4SLinus Torvalds * @newheadroom: new free bytes at head 6361da177e4SLinus Torvalds * @newtailroom: new free bytes at tail 6371da177e4SLinus Torvalds * @gfp_mask: allocation priority 6381da177e4SLinus Torvalds * 6391da177e4SLinus Torvalds * Make a copy of both an &sk_buff and its data and while doing so 6401da177e4SLinus Torvalds * allocate additional space. 6411da177e4SLinus Torvalds * 6421da177e4SLinus Torvalds * This is used when the caller wishes to modify the data and needs a 6431da177e4SLinus Torvalds * private copy of the data to alter as well as more space for new fields. 6441da177e4SLinus Torvalds * Returns %NULL on failure or the pointer to the buffer 6451da177e4SLinus Torvalds * on success. The returned buffer has a reference count of 1. 6461da177e4SLinus Torvalds * 6471da177e4SLinus Torvalds * You must pass %GFP_ATOMIC as the allocation priority if this function 6481da177e4SLinus Torvalds * is called from an interrupt. 6491da177e4SLinus Torvalds * 6501da177e4SLinus Torvalds * BUG ALERT: ip_summed is not copied. Why does this work? Is it used 6511da177e4SLinus Torvalds * only by netfilter in the cases when checksum is recalculated? --ANK 6521da177e4SLinus Torvalds */ 6531da177e4SLinus Torvalds struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 6541da177e4SLinus Torvalds int newheadroom, int newtailroom, int gfp_mask) 6551da177e4SLinus Torvalds { 6561da177e4SLinus Torvalds /* 6571da177e4SLinus Torvalds * Allocate the copy buffer 6581da177e4SLinus Torvalds */ 6591da177e4SLinus Torvalds struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, 6601da177e4SLinus Torvalds gfp_mask); 6611da177e4SLinus Torvalds int head_copy_len, head_copy_off; 6621da177e4SLinus Torvalds 6631da177e4SLinus Torvalds if (!n) 6641da177e4SLinus Torvalds return NULL; 6651da177e4SLinus Torvalds 6661da177e4SLinus Torvalds skb_reserve(n, newheadroom); 6671da177e4SLinus Torvalds 6681da177e4SLinus Torvalds /* Set the tail pointer and length */ 6691da177e4SLinus Torvalds skb_put(n, skb->len); 6701da177e4SLinus Torvalds 6711da177e4SLinus Torvalds head_copy_len = skb_headroom(skb); 6721da177e4SLinus Torvalds head_copy_off = 0; 6731da177e4SLinus Torvalds if (newheadroom <= head_copy_len) 6741da177e4SLinus Torvalds head_copy_len = newheadroom; 6751da177e4SLinus Torvalds else 6761da177e4SLinus Torvalds head_copy_off = newheadroom - head_copy_len; 6771da177e4SLinus Torvalds 6781da177e4SLinus Torvalds /* Copy the linear header and data. */ 6791da177e4SLinus Torvalds if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, 6801da177e4SLinus Torvalds skb->len + head_copy_len)) 6811da177e4SLinus Torvalds BUG(); 6821da177e4SLinus Torvalds 6831da177e4SLinus Torvalds copy_skb_header(n, skb); 6841da177e4SLinus Torvalds 6851da177e4SLinus Torvalds return n; 6861da177e4SLinus Torvalds } 6871da177e4SLinus Torvalds 6881da177e4SLinus Torvalds /** 6891da177e4SLinus Torvalds * skb_pad - zero pad the tail of an skb 6901da177e4SLinus Torvalds * @skb: buffer to pad 6911da177e4SLinus Torvalds * @pad: space to pad 6921da177e4SLinus Torvalds * 6931da177e4SLinus Torvalds * Ensure that a buffer is followed by a padding area that is zero 6941da177e4SLinus Torvalds * filled. Used by network drivers which may DMA or transfer data 6951da177e4SLinus Torvalds * beyond the buffer end onto the wire. 6961da177e4SLinus Torvalds * 6971da177e4SLinus Torvalds * May return NULL in out of memory cases. 6981da177e4SLinus Torvalds */ 6991da177e4SLinus Torvalds 7001da177e4SLinus Torvalds struct sk_buff *skb_pad(struct sk_buff *skb, int pad) 7011da177e4SLinus Torvalds { 7021da177e4SLinus Torvalds struct sk_buff *nskb; 7031da177e4SLinus Torvalds 7041da177e4SLinus Torvalds /* If the skbuff is non linear tailroom is always zero.. */ 7051da177e4SLinus Torvalds if (skb_tailroom(skb) >= pad) { 7061da177e4SLinus Torvalds memset(skb->data+skb->len, 0, pad); 7071da177e4SLinus Torvalds return skb; 7081da177e4SLinus Torvalds } 7091da177e4SLinus Torvalds 7101da177e4SLinus Torvalds nskb = skb_copy_expand(skb, skb_headroom(skb), skb_tailroom(skb) + pad, GFP_ATOMIC); 7111da177e4SLinus Torvalds kfree_skb(skb); 7121da177e4SLinus Torvalds if (nskb) 7131da177e4SLinus Torvalds memset(nskb->data+nskb->len, 0, pad); 7141da177e4SLinus Torvalds return nskb; 7151da177e4SLinus Torvalds } 7161da177e4SLinus Torvalds 7171da177e4SLinus Torvalds /* Trims skb to length len. It can change skb pointers, if "realloc" is 1. 7181da177e4SLinus Torvalds * If realloc==0 and trimming is impossible without change of data, 7191da177e4SLinus Torvalds * it is BUG(). 7201da177e4SLinus Torvalds */ 7211da177e4SLinus Torvalds 7221da177e4SLinus Torvalds int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc) 7231da177e4SLinus Torvalds { 7241da177e4SLinus Torvalds int offset = skb_headlen(skb); 7251da177e4SLinus Torvalds int nfrags = skb_shinfo(skb)->nr_frags; 7261da177e4SLinus Torvalds int i; 7271da177e4SLinus Torvalds 7281da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 7291da177e4SLinus Torvalds int end = offset + skb_shinfo(skb)->frags[i].size; 7301da177e4SLinus Torvalds if (end > len) { 7311da177e4SLinus Torvalds if (skb_cloned(skb)) { 7321da177e4SLinus Torvalds if (!realloc) 7331da177e4SLinus Torvalds BUG(); 7341da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 7351da177e4SLinus Torvalds return -ENOMEM; 7361da177e4SLinus Torvalds } 7371da177e4SLinus Torvalds if (len <= offset) { 7381da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 7391da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags--; 7401da177e4SLinus Torvalds } else { 7411da177e4SLinus Torvalds skb_shinfo(skb)->frags[i].size = len - offset; 7421da177e4SLinus Torvalds } 7431da177e4SLinus Torvalds } 7441da177e4SLinus Torvalds offset = end; 7451da177e4SLinus Torvalds } 7461da177e4SLinus Torvalds 7471da177e4SLinus Torvalds if (offset < len) { 7481da177e4SLinus Torvalds skb->data_len -= skb->len - len; 7491da177e4SLinus Torvalds skb->len = len; 7501da177e4SLinus Torvalds } else { 7511da177e4SLinus Torvalds if (len <= skb_headlen(skb)) { 7521da177e4SLinus Torvalds skb->len = len; 7531da177e4SLinus Torvalds skb->data_len = 0; 7541da177e4SLinus Torvalds skb->tail = skb->data + len; 7551da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list && !skb_cloned(skb)) 7561da177e4SLinus Torvalds skb_drop_fraglist(skb); 7571da177e4SLinus Torvalds } else { 7581da177e4SLinus Torvalds skb->data_len -= skb->len - len; 7591da177e4SLinus Torvalds skb->len = len; 7601da177e4SLinus Torvalds } 7611da177e4SLinus Torvalds } 7621da177e4SLinus Torvalds 7631da177e4SLinus Torvalds return 0; 7641da177e4SLinus Torvalds } 7651da177e4SLinus Torvalds 7661da177e4SLinus Torvalds /** 7671da177e4SLinus Torvalds * __pskb_pull_tail - advance tail of skb header 7681da177e4SLinus Torvalds * @skb: buffer to reallocate 7691da177e4SLinus Torvalds * @delta: number of bytes to advance tail 7701da177e4SLinus Torvalds * 7711da177e4SLinus Torvalds * The function makes a sense only on a fragmented &sk_buff, 7721da177e4SLinus Torvalds * it expands header moving its tail forward and copying necessary 7731da177e4SLinus Torvalds * data from fragmented part. 7741da177e4SLinus Torvalds * 7751da177e4SLinus Torvalds * &sk_buff MUST have reference count of 1. 7761da177e4SLinus Torvalds * 7771da177e4SLinus Torvalds * Returns %NULL (and &sk_buff does not change) if pull failed 7781da177e4SLinus Torvalds * or value of new tail of skb in the case of success. 7791da177e4SLinus Torvalds * 7801da177e4SLinus Torvalds * All the pointers pointing into skb header may change and must be 7811da177e4SLinus Torvalds * reloaded after call to this function. 7821da177e4SLinus Torvalds */ 7831da177e4SLinus Torvalds 7841da177e4SLinus Torvalds /* Moves tail of skb head forward, copying data from fragmented part, 7851da177e4SLinus Torvalds * when it is necessary. 7861da177e4SLinus Torvalds * 1. It may fail due to malloc failure. 7871da177e4SLinus Torvalds * 2. It may change skb pointers. 7881da177e4SLinus Torvalds * 7891da177e4SLinus Torvalds * It is pretty complicated. Luckily, it is called only in exceptional cases. 7901da177e4SLinus Torvalds */ 7911da177e4SLinus Torvalds unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) 7921da177e4SLinus Torvalds { 7931da177e4SLinus Torvalds /* If skb has not enough free space at tail, get new one 7941da177e4SLinus Torvalds * plus 128 bytes for future expansions. If we have enough 7951da177e4SLinus Torvalds * room at tail, reallocate without expansion only if skb is cloned. 7961da177e4SLinus Torvalds */ 7971da177e4SLinus Torvalds int i, k, eat = (skb->tail + delta) - skb->end; 7981da177e4SLinus Torvalds 7991da177e4SLinus Torvalds if (eat > 0 || skb_cloned(skb)) { 8001da177e4SLinus Torvalds if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, 8011da177e4SLinus Torvalds GFP_ATOMIC)) 8021da177e4SLinus Torvalds return NULL; 8031da177e4SLinus Torvalds } 8041da177e4SLinus Torvalds 8051da177e4SLinus Torvalds if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta)) 8061da177e4SLinus Torvalds BUG(); 8071da177e4SLinus Torvalds 8081da177e4SLinus Torvalds /* Optimization: no fragments, no reasons to preestimate 8091da177e4SLinus Torvalds * size of pulled pages. Superb. 8101da177e4SLinus Torvalds */ 8111da177e4SLinus Torvalds if (!skb_shinfo(skb)->frag_list) 8121da177e4SLinus Torvalds goto pull_pages; 8131da177e4SLinus Torvalds 8141da177e4SLinus Torvalds /* Estimate size of pulled pages. */ 8151da177e4SLinus Torvalds eat = delta; 8161da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 8171da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size >= eat) 8181da177e4SLinus Torvalds goto pull_pages; 8191da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 8201da177e4SLinus Torvalds } 8211da177e4SLinus Torvalds 8221da177e4SLinus Torvalds /* If we need update frag list, we are in troubles. 8231da177e4SLinus Torvalds * Certainly, it possible to add an offset to skb data, 8241da177e4SLinus Torvalds * but taking into account that pulling is expected to 8251da177e4SLinus Torvalds * be very rare operation, it is worth to fight against 8261da177e4SLinus Torvalds * further bloating skb head and crucify ourselves here instead. 8271da177e4SLinus Torvalds * Pure masohism, indeed. 8)8) 8281da177e4SLinus Torvalds */ 8291da177e4SLinus Torvalds if (eat) { 8301da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 8311da177e4SLinus Torvalds struct sk_buff *clone = NULL; 8321da177e4SLinus Torvalds struct sk_buff *insp = NULL; 8331da177e4SLinus Torvalds 8341da177e4SLinus Torvalds do { 8351da177e4SLinus Torvalds if (!list) 8361da177e4SLinus Torvalds BUG(); 8371da177e4SLinus Torvalds 8381da177e4SLinus Torvalds if (list->len <= eat) { 8391da177e4SLinus Torvalds /* Eaten as whole. */ 8401da177e4SLinus Torvalds eat -= list->len; 8411da177e4SLinus Torvalds list = list->next; 8421da177e4SLinus Torvalds insp = list; 8431da177e4SLinus Torvalds } else { 8441da177e4SLinus Torvalds /* Eaten partially. */ 8451da177e4SLinus Torvalds 8461da177e4SLinus Torvalds if (skb_shared(list)) { 8471da177e4SLinus Torvalds /* Sucks! We need to fork list. :-( */ 8481da177e4SLinus Torvalds clone = skb_clone(list, GFP_ATOMIC); 8491da177e4SLinus Torvalds if (!clone) 8501da177e4SLinus Torvalds return NULL; 8511da177e4SLinus Torvalds insp = list->next; 8521da177e4SLinus Torvalds list = clone; 8531da177e4SLinus Torvalds } else { 8541da177e4SLinus Torvalds /* This may be pulled without 8551da177e4SLinus Torvalds * problems. */ 8561da177e4SLinus Torvalds insp = list; 8571da177e4SLinus Torvalds } 8581da177e4SLinus Torvalds if (!pskb_pull(list, eat)) { 8591da177e4SLinus Torvalds if (clone) 8601da177e4SLinus Torvalds kfree_skb(clone); 8611da177e4SLinus Torvalds return NULL; 8621da177e4SLinus Torvalds } 8631da177e4SLinus Torvalds break; 8641da177e4SLinus Torvalds } 8651da177e4SLinus Torvalds } while (eat); 8661da177e4SLinus Torvalds 8671da177e4SLinus Torvalds /* Free pulled out fragments. */ 8681da177e4SLinus Torvalds while ((list = skb_shinfo(skb)->frag_list) != insp) { 8691da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = list->next; 8701da177e4SLinus Torvalds kfree_skb(list); 8711da177e4SLinus Torvalds } 8721da177e4SLinus Torvalds /* And insert new clone at head. */ 8731da177e4SLinus Torvalds if (clone) { 8741da177e4SLinus Torvalds clone->next = list; 8751da177e4SLinus Torvalds skb_shinfo(skb)->frag_list = clone; 8761da177e4SLinus Torvalds } 8771da177e4SLinus Torvalds } 8781da177e4SLinus Torvalds /* Success! Now we may commit changes to skb data. */ 8791da177e4SLinus Torvalds 8801da177e4SLinus Torvalds pull_pages: 8811da177e4SLinus Torvalds eat = delta; 8821da177e4SLinus Torvalds k = 0; 8831da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 8841da177e4SLinus Torvalds if (skb_shinfo(skb)->frags[i].size <= eat) { 8851da177e4SLinus Torvalds put_page(skb_shinfo(skb)->frags[i].page); 8861da177e4SLinus Torvalds eat -= skb_shinfo(skb)->frags[i].size; 8871da177e4SLinus Torvalds } else { 8881da177e4SLinus Torvalds skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; 8891da177e4SLinus Torvalds if (eat) { 8901da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].page_offset += eat; 8911da177e4SLinus Torvalds skb_shinfo(skb)->frags[k].size -= eat; 8921da177e4SLinus Torvalds eat = 0; 8931da177e4SLinus Torvalds } 8941da177e4SLinus Torvalds k++; 8951da177e4SLinus Torvalds } 8961da177e4SLinus Torvalds } 8971da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = k; 8981da177e4SLinus Torvalds 8991da177e4SLinus Torvalds skb->tail += delta; 9001da177e4SLinus Torvalds skb->data_len -= delta; 9011da177e4SLinus Torvalds 9021da177e4SLinus Torvalds return skb->tail; 9031da177e4SLinus Torvalds } 9041da177e4SLinus Torvalds 9051da177e4SLinus Torvalds /* Copy some data bits from skb to kernel buffer. */ 9061da177e4SLinus Torvalds 9071da177e4SLinus Torvalds int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) 9081da177e4SLinus Torvalds { 9091da177e4SLinus Torvalds int i, copy; 9101da177e4SLinus Torvalds int start = skb_headlen(skb); 9111da177e4SLinus Torvalds 9121da177e4SLinus Torvalds if (offset > (int)skb->len - len) 9131da177e4SLinus Torvalds goto fault; 9141da177e4SLinus Torvalds 9151da177e4SLinus Torvalds /* Copy header. */ 9161da177e4SLinus Torvalds if ((copy = start - offset) > 0) { 9171da177e4SLinus Torvalds if (copy > len) 9181da177e4SLinus Torvalds copy = len; 9191da177e4SLinus Torvalds memcpy(to, skb->data + offset, copy); 9201da177e4SLinus Torvalds if ((len -= copy) == 0) 9211da177e4SLinus Torvalds return 0; 9221da177e4SLinus Torvalds offset += copy; 9231da177e4SLinus Torvalds to += copy; 9241da177e4SLinus Torvalds } 9251da177e4SLinus Torvalds 9261da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 9271da177e4SLinus Torvalds int end; 9281da177e4SLinus Torvalds 9291da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 9301da177e4SLinus Torvalds 9311da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 9321da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 9331da177e4SLinus Torvalds u8 *vaddr; 9341da177e4SLinus Torvalds 9351da177e4SLinus Torvalds if (copy > len) 9361da177e4SLinus Torvalds copy = len; 9371da177e4SLinus Torvalds 9381da177e4SLinus Torvalds vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); 9391da177e4SLinus Torvalds memcpy(to, 9401da177e4SLinus Torvalds vaddr + skb_shinfo(skb)->frags[i].page_offset+ 9411da177e4SLinus Torvalds offset - start, copy); 9421da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 9431da177e4SLinus Torvalds 9441da177e4SLinus Torvalds if ((len -= copy) == 0) 9451da177e4SLinus Torvalds return 0; 9461da177e4SLinus Torvalds offset += copy; 9471da177e4SLinus Torvalds to += copy; 9481da177e4SLinus Torvalds } 9491da177e4SLinus Torvalds start = end; 9501da177e4SLinus Torvalds } 9511da177e4SLinus Torvalds 9521da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 9531da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 9541da177e4SLinus Torvalds 9551da177e4SLinus Torvalds for (; list; list = list->next) { 9561da177e4SLinus Torvalds int end; 9571da177e4SLinus Torvalds 9581da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 9591da177e4SLinus Torvalds 9601da177e4SLinus Torvalds end = start + list->len; 9611da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 9621da177e4SLinus Torvalds if (copy > len) 9631da177e4SLinus Torvalds copy = len; 9641da177e4SLinus Torvalds if (skb_copy_bits(list, offset - start, 9651da177e4SLinus Torvalds to, copy)) 9661da177e4SLinus Torvalds goto fault; 9671da177e4SLinus Torvalds if ((len -= copy) == 0) 9681da177e4SLinus Torvalds return 0; 9691da177e4SLinus Torvalds offset += copy; 9701da177e4SLinus Torvalds to += copy; 9711da177e4SLinus Torvalds } 9721da177e4SLinus Torvalds start = end; 9731da177e4SLinus Torvalds } 9741da177e4SLinus Torvalds } 9751da177e4SLinus Torvalds if (!len) 9761da177e4SLinus Torvalds return 0; 9771da177e4SLinus Torvalds 9781da177e4SLinus Torvalds fault: 9791da177e4SLinus Torvalds return -EFAULT; 9801da177e4SLinus Torvalds } 9811da177e4SLinus Torvalds 982357b40a1SHerbert Xu /** 983357b40a1SHerbert Xu * skb_store_bits - store bits from kernel buffer to skb 984357b40a1SHerbert Xu * @skb: destination buffer 985357b40a1SHerbert Xu * @offset: offset in destination 986357b40a1SHerbert Xu * @from: source buffer 987357b40a1SHerbert Xu * @len: number of bytes to copy 988357b40a1SHerbert Xu * 989357b40a1SHerbert Xu * Copy the specified number of bytes from the source buffer to the 990357b40a1SHerbert Xu * destination skb. This function handles all the messy bits of 991357b40a1SHerbert Xu * traversing fragment lists and such. 992357b40a1SHerbert Xu */ 993357b40a1SHerbert Xu 994357b40a1SHerbert Xu int skb_store_bits(const struct sk_buff *skb, int offset, void *from, int len) 995357b40a1SHerbert Xu { 996357b40a1SHerbert Xu int i, copy; 997357b40a1SHerbert Xu int start = skb_headlen(skb); 998357b40a1SHerbert Xu 999357b40a1SHerbert Xu if (offset > (int)skb->len - len) 1000357b40a1SHerbert Xu goto fault; 1001357b40a1SHerbert Xu 1002357b40a1SHerbert Xu if ((copy = start - offset) > 0) { 1003357b40a1SHerbert Xu if (copy > len) 1004357b40a1SHerbert Xu copy = len; 1005357b40a1SHerbert Xu memcpy(skb->data + offset, from, copy); 1006357b40a1SHerbert Xu if ((len -= copy) == 0) 1007357b40a1SHerbert Xu return 0; 1008357b40a1SHerbert Xu offset += copy; 1009357b40a1SHerbert Xu from += copy; 1010357b40a1SHerbert Xu } 1011357b40a1SHerbert Xu 1012357b40a1SHerbert Xu for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 1013357b40a1SHerbert Xu skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 1014357b40a1SHerbert Xu int end; 1015357b40a1SHerbert Xu 1016357b40a1SHerbert Xu BUG_TRAP(start <= offset + len); 1017357b40a1SHerbert Xu 1018357b40a1SHerbert Xu end = start + frag->size; 1019357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1020357b40a1SHerbert Xu u8 *vaddr; 1021357b40a1SHerbert Xu 1022357b40a1SHerbert Xu if (copy > len) 1023357b40a1SHerbert Xu copy = len; 1024357b40a1SHerbert Xu 1025357b40a1SHerbert Xu vaddr = kmap_skb_frag(frag); 1026357b40a1SHerbert Xu memcpy(vaddr + frag->page_offset + offset - start, 1027357b40a1SHerbert Xu from, copy); 1028357b40a1SHerbert Xu kunmap_skb_frag(vaddr); 1029357b40a1SHerbert Xu 1030357b40a1SHerbert Xu if ((len -= copy) == 0) 1031357b40a1SHerbert Xu return 0; 1032357b40a1SHerbert Xu offset += copy; 1033357b40a1SHerbert Xu from += copy; 1034357b40a1SHerbert Xu } 1035357b40a1SHerbert Xu start = end; 1036357b40a1SHerbert Xu } 1037357b40a1SHerbert Xu 1038357b40a1SHerbert Xu if (skb_shinfo(skb)->frag_list) { 1039357b40a1SHerbert Xu struct sk_buff *list = skb_shinfo(skb)->frag_list; 1040357b40a1SHerbert Xu 1041357b40a1SHerbert Xu for (; list; list = list->next) { 1042357b40a1SHerbert Xu int end; 1043357b40a1SHerbert Xu 1044357b40a1SHerbert Xu BUG_TRAP(start <= offset + len); 1045357b40a1SHerbert Xu 1046357b40a1SHerbert Xu end = start + list->len; 1047357b40a1SHerbert Xu if ((copy = end - offset) > 0) { 1048357b40a1SHerbert Xu if (copy > len) 1049357b40a1SHerbert Xu copy = len; 1050357b40a1SHerbert Xu if (skb_store_bits(list, offset - start, 1051357b40a1SHerbert Xu from, copy)) 1052357b40a1SHerbert Xu goto fault; 1053357b40a1SHerbert Xu if ((len -= copy) == 0) 1054357b40a1SHerbert Xu return 0; 1055357b40a1SHerbert Xu offset += copy; 1056357b40a1SHerbert Xu from += copy; 1057357b40a1SHerbert Xu } 1058357b40a1SHerbert Xu start = end; 1059357b40a1SHerbert Xu } 1060357b40a1SHerbert Xu } 1061357b40a1SHerbert Xu if (!len) 1062357b40a1SHerbert Xu return 0; 1063357b40a1SHerbert Xu 1064357b40a1SHerbert Xu fault: 1065357b40a1SHerbert Xu return -EFAULT; 1066357b40a1SHerbert Xu } 1067357b40a1SHerbert Xu 1068357b40a1SHerbert Xu EXPORT_SYMBOL(skb_store_bits); 1069357b40a1SHerbert Xu 10701da177e4SLinus Torvalds /* Checksum skb data. */ 10711da177e4SLinus Torvalds 10721da177e4SLinus Torvalds unsigned int skb_checksum(const struct sk_buff *skb, int offset, 10731da177e4SLinus Torvalds int len, unsigned int csum) 10741da177e4SLinus Torvalds { 10751da177e4SLinus Torvalds int start = skb_headlen(skb); 10761da177e4SLinus Torvalds int i, copy = start - offset; 10771da177e4SLinus Torvalds int pos = 0; 10781da177e4SLinus Torvalds 10791da177e4SLinus Torvalds /* Checksum header. */ 10801da177e4SLinus Torvalds if (copy > 0) { 10811da177e4SLinus Torvalds if (copy > len) 10821da177e4SLinus Torvalds copy = len; 10831da177e4SLinus Torvalds csum = csum_partial(skb->data + offset, copy, csum); 10841da177e4SLinus Torvalds if ((len -= copy) == 0) 10851da177e4SLinus Torvalds return csum; 10861da177e4SLinus Torvalds offset += copy; 10871da177e4SLinus Torvalds pos = copy; 10881da177e4SLinus Torvalds } 10891da177e4SLinus Torvalds 10901da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 10911da177e4SLinus Torvalds int end; 10921da177e4SLinus Torvalds 10931da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 10941da177e4SLinus Torvalds 10951da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 10961da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 10971da177e4SLinus Torvalds unsigned int csum2; 10981da177e4SLinus Torvalds u8 *vaddr; 10991da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 11001da177e4SLinus Torvalds 11011da177e4SLinus Torvalds if (copy > len) 11021da177e4SLinus Torvalds copy = len; 11031da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 11041da177e4SLinus Torvalds csum2 = csum_partial(vaddr + frag->page_offset + 11051da177e4SLinus Torvalds offset - start, copy, 0); 11061da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 11071da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 11081da177e4SLinus Torvalds if (!(len -= copy)) 11091da177e4SLinus Torvalds return csum; 11101da177e4SLinus Torvalds offset += copy; 11111da177e4SLinus Torvalds pos += copy; 11121da177e4SLinus Torvalds } 11131da177e4SLinus Torvalds start = end; 11141da177e4SLinus Torvalds } 11151da177e4SLinus Torvalds 11161da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 11171da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 11181da177e4SLinus Torvalds 11191da177e4SLinus Torvalds for (; list; list = list->next) { 11201da177e4SLinus Torvalds int end; 11211da177e4SLinus Torvalds 11221da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 11231da177e4SLinus Torvalds 11241da177e4SLinus Torvalds end = start + list->len; 11251da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 11261da177e4SLinus Torvalds unsigned int csum2; 11271da177e4SLinus Torvalds if (copy > len) 11281da177e4SLinus Torvalds copy = len; 11291da177e4SLinus Torvalds csum2 = skb_checksum(list, offset - start, 11301da177e4SLinus Torvalds copy, 0); 11311da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 11321da177e4SLinus Torvalds if ((len -= copy) == 0) 11331da177e4SLinus Torvalds return csum; 11341da177e4SLinus Torvalds offset += copy; 11351da177e4SLinus Torvalds pos += copy; 11361da177e4SLinus Torvalds } 11371da177e4SLinus Torvalds start = end; 11381da177e4SLinus Torvalds } 11391da177e4SLinus Torvalds } 11401da177e4SLinus Torvalds if (len) 11411da177e4SLinus Torvalds BUG(); 11421da177e4SLinus Torvalds 11431da177e4SLinus Torvalds return csum; 11441da177e4SLinus Torvalds } 11451da177e4SLinus Torvalds 11461da177e4SLinus Torvalds /* Both of above in one bottle. */ 11471da177e4SLinus Torvalds 11481da177e4SLinus Torvalds unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 11491da177e4SLinus Torvalds u8 *to, int len, unsigned int csum) 11501da177e4SLinus Torvalds { 11511da177e4SLinus Torvalds int start = skb_headlen(skb); 11521da177e4SLinus Torvalds int i, copy = start - offset; 11531da177e4SLinus Torvalds int pos = 0; 11541da177e4SLinus Torvalds 11551da177e4SLinus Torvalds /* Copy header. */ 11561da177e4SLinus Torvalds if (copy > 0) { 11571da177e4SLinus Torvalds if (copy > len) 11581da177e4SLinus Torvalds copy = len; 11591da177e4SLinus Torvalds csum = csum_partial_copy_nocheck(skb->data + offset, to, 11601da177e4SLinus Torvalds copy, csum); 11611da177e4SLinus Torvalds if ((len -= copy) == 0) 11621da177e4SLinus Torvalds return csum; 11631da177e4SLinus Torvalds offset += copy; 11641da177e4SLinus Torvalds to += copy; 11651da177e4SLinus Torvalds pos = copy; 11661da177e4SLinus Torvalds } 11671da177e4SLinus Torvalds 11681da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 11691da177e4SLinus Torvalds int end; 11701da177e4SLinus Torvalds 11711da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 11721da177e4SLinus Torvalds 11731da177e4SLinus Torvalds end = start + skb_shinfo(skb)->frags[i].size; 11741da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 11751da177e4SLinus Torvalds unsigned int csum2; 11761da177e4SLinus Torvalds u8 *vaddr; 11771da177e4SLinus Torvalds skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 11781da177e4SLinus Torvalds 11791da177e4SLinus Torvalds if (copy > len) 11801da177e4SLinus Torvalds copy = len; 11811da177e4SLinus Torvalds vaddr = kmap_skb_frag(frag); 11821da177e4SLinus Torvalds csum2 = csum_partial_copy_nocheck(vaddr + 11831da177e4SLinus Torvalds frag->page_offset + 11841da177e4SLinus Torvalds offset - start, to, 11851da177e4SLinus Torvalds copy, 0); 11861da177e4SLinus Torvalds kunmap_skb_frag(vaddr); 11871da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 11881da177e4SLinus Torvalds if (!(len -= copy)) 11891da177e4SLinus Torvalds return csum; 11901da177e4SLinus Torvalds offset += copy; 11911da177e4SLinus Torvalds to += copy; 11921da177e4SLinus Torvalds pos += copy; 11931da177e4SLinus Torvalds } 11941da177e4SLinus Torvalds start = end; 11951da177e4SLinus Torvalds } 11961da177e4SLinus Torvalds 11971da177e4SLinus Torvalds if (skb_shinfo(skb)->frag_list) { 11981da177e4SLinus Torvalds struct sk_buff *list = skb_shinfo(skb)->frag_list; 11991da177e4SLinus Torvalds 12001da177e4SLinus Torvalds for (; list; list = list->next) { 12011da177e4SLinus Torvalds unsigned int csum2; 12021da177e4SLinus Torvalds int end; 12031da177e4SLinus Torvalds 12041da177e4SLinus Torvalds BUG_TRAP(start <= offset + len); 12051da177e4SLinus Torvalds 12061da177e4SLinus Torvalds end = start + list->len; 12071da177e4SLinus Torvalds if ((copy = end - offset) > 0) { 12081da177e4SLinus Torvalds if (copy > len) 12091da177e4SLinus Torvalds copy = len; 12101da177e4SLinus Torvalds csum2 = skb_copy_and_csum_bits(list, 12111da177e4SLinus Torvalds offset - start, 12121da177e4SLinus Torvalds to, copy, 0); 12131da177e4SLinus Torvalds csum = csum_block_add(csum, csum2, pos); 12141da177e4SLinus Torvalds if ((len -= copy) == 0) 12151da177e4SLinus Torvalds return csum; 12161da177e4SLinus Torvalds offset += copy; 12171da177e4SLinus Torvalds to += copy; 12181da177e4SLinus Torvalds pos += copy; 12191da177e4SLinus Torvalds } 12201da177e4SLinus Torvalds start = end; 12211da177e4SLinus Torvalds } 12221da177e4SLinus Torvalds } 12231da177e4SLinus Torvalds if (len) 12241da177e4SLinus Torvalds BUG(); 12251da177e4SLinus Torvalds return csum; 12261da177e4SLinus Torvalds } 12271da177e4SLinus Torvalds 12281da177e4SLinus Torvalds void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) 12291da177e4SLinus Torvalds { 12301da177e4SLinus Torvalds unsigned int csum; 12311da177e4SLinus Torvalds long csstart; 12321da177e4SLinus Torvalds 12331da177e4SLinus Torvalds if (skb->ip_summed == CHECKSUM_HW) 12341da177e4SLinus Torvalds csstart = skb->h.raw - skb->data; 12351da177e4SLinus Torvalds else 12361da177e4SLinus Torvalds csstart = skb_headlen(skb); 12371da177e4SLinus Torvalds 12381da177e4SLinus Torvalds if (csstart > skb_headlen(skb)) 12391da177e4SLinus Torvalds BUG(); 12401da177e4SLinus Torvalds 12411da177e4SLinus Torvalds memcpy(to, skb->data, csstart); 12421da177e4SLinus Torvalds 12431da177e4SLinus Torvalds csum = 0; 12441da177e4SLinus Torvalds if (csstart != skb->len) 12451da177e4SLinus Torvalds csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, 12461da177e4SLinus Torvalds skb->len - csstart, 0); 12471da177e4SLinus Torvalds 12481da177e4SLinus Torvalds if (skb->ip_summed == CHECKSUM_HW) { 12491da177e4SLinus Torvalds long csstuff = csstart + skb->csum; 12501da177e4SLinus Torvalds 12511da177e4SLinus Torvalds *((unsigned short *)(to + csstuff)) = csum_fold(csum); 12521da177e4SLinus Torvalds } 12531da177e4SLinus Torvalds } 12541da177e4SLinus Torvalds 12551da177e4SLinus Torvalds /** 12561da177e4SLinus Torvalds * skb_dequeue - remove from the head of the queue 12571da177e4SLinus Torvalds * @list: list to dequeue from 12581da177e4SLinus Torvalds * 12591da177e4SLinus Torvalds * Remove the head of the list. The list lock is taken so the function 12601da177e4SLinus Torvalds * may be used safely with other locking list functions. The head item is 12611da177e4SLinus Torvalds * returned or %NULL if the list is empty. 12621da177e4SLinus Torvalds */ 12631da177e4SLinus Torvalds 12641da177e4SLinus Torvalds struct sk_buff *skb_dequeue(struct sk_buff_head *list) 12651da177e4SLinus Torvalds { 12661da177e4SLinus Torvalds unsigned long flags; 12671da177e4SLinus Torvalds struct sk_buff *result; 12681da177e4SLinus Torvalds 12691da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 12701da177e4SLinus Torvalds result = __skb_dequeue(list); 12711da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 12721da177e4SLinus Torvalds return result; 12731da177e4SLinus Torvalds } 12741da177e4SLinus Torvalds 12751da177e4SLinus Torvalds /** 12761da177e4SLinus Torvalds * skb_dequeue_tail - remove from the tail of the queue 12771da177e4SLinus Torvalds * @list: list to dequeue from 12781da177e4SLinus Torvalds * 12791da177e4SLinus Torvalds * Remove the tail of the list. The list lock is taken so the function 12801da177e4SLinus Torvalds * may be used safely with other locking list functions. The tail item is 12811da177e4SLinus Torvalds * returned or %NULL if the list is empty. 12821da177e4SLinus Torvalds */ 12831da177e4SLinus Torvalds struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) 12841da177e4SLinus Torvalds { 12851da177e4SLinus Torvalds unsigned long flags; 12861da177e4SLinus Torvalds struct sk_buff *result; 12871da177e4SLinus Torvalds 12881da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 12891da177e4SLinus Torvalds result = __skb_dequeue_tail(list); 12901da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 12911da177e4SLinus Torvalds return result; 12921da177e4SLinus Torvalds } 12931da177e4SLinus Torvalds 12941da177e4SLinus Torvalds /** 12951da177e4SLinus Torvalds * skb_queue_purge - empty a list 12961da177e4SLinus Torvalds * @list: list to empty 12971da177e4SLinus Torvalds * 12981da177e4SLinus Torvalds * Delete all buffers on an &sk_buff list. Each buffer is removed from 12991da177e4SLinus Torvalds * the list and one reference dropped. This function takes the list 13001da177e4SLinus Torvalds * lock and is atomic with respect to other list locking functions. 13011da177e4SLinus Torvalds */ 13021da177e4SLinus Torvalds void skb_queue_purge(struct sk_buff_head *list) 13031da177e4SLinus Torvalds { 13041da177e4SLinus Torvalds struct sk_buff *skb; 13051da177e4SLinus Torvalds while ((skb = skb_dequeue(list)) != NULL) 13061da177e4SLinus Torvalds kfree_skb(skb); 13071da177e4SLinus Torvalds } 13081da177e4SLinus Torvalds 13091da177e4SLinus Torvalds /** 13101da177e4SLinus Torvalds * skb_queue_head - queue a buffer at the list head 13111da177e4SLinus Torvalds * @list: list to use 13121da177e4SLinus Torvalds * @newsk: buffer to queue 13131da177e4SLinus Torvalds * 13141da177e4SLinus Torvalds * Queue a buffer at the start of the list. This function takes the 13151da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 13161da177e4SLinus Torvalds * safely. 13171da177e4SLinus Torvalds * 13181da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 13191da177e4SLinus Torvalds */ 13201da177e4SLinus Torvalds void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) 13211da177e4SLinus Torvalds { 13221da177e4SLinus Torvalds unsigned long flags; 13231da177e4SLinus Torvalds 13241da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 13251da177e4SLinus Torvalds __skb_queue_head(list, newsk); 13261da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 13271da177e4SLinus Torvalds } 13281da177e4SLinus Torvalds 13291da177e4SLinus Torvalds /** 13301da177e4SLinus Torvalds * skb_queue_tail - queue a buffer at the list tail 13311da177e4SLinus Torvalds * @list: list to use 13321da177e4SLinus Torvalds * @newsk: buffer to queue 13331da177e4SLinus Torvalds * 13341da177e4SLinus Torvalds * Queue a buffer at the tail of the list. This function takes the 13351da177e4SLinus Torvalds * list lock and can be used safely with other locking &sk_buff functions 13361da177e4SLinus Torvalds * safely. 13371da177e4SLinus Torvalds * 13381da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 13391da177e4SLinus Torvalds */ 13401da177e4SLinus Torvalds void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) 13411da177e4SLinus Torvalds { 13421da177e4SLinus Torvalds unsigned long flags; 13431da177e4SLinus Torvalds 13441da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 13451da177e4SLinus Torvalds __skb_queue_tail(list, newsk); 13461da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 13471da177e4SLinus Torvalds } 13481da177e4SLinus Torvalds /** 13491da177e4SLinus Torvalds * skb_unlink - remove a buffer from a list 13501da177e4SLinus Torvalds * @skb: buffer to remove 13511da177e4SLinus Torvalds * 13521da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 13531da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls 13541da177e4SLinus Torvalds * 13551da177e4SLinus Torvalds * Works even without knowing the list it is sitting on, which can be 13561da177e4SLinus Torvalds * handy at times. It also means that THE LIST MUST EXIST when you 13571da177e4SLinus Torvalds * unlink. Thus a list must have its contents unlinked before it is 13581da177e4SLinus Torvalds * destroyed. 13591da177e4SLinus Torvalds */ 13601da177e4SLinus Torvalds void skb_unlink(struct sk_buff *skb) 13611da177e4SLinus Torvalds { 13621da177e4SLinus Torvalds struct sk_buff_head *list = skb->list; 13631da177e4SLinus Torvalds 13641da177e4SLinus Torvalds if (list) { 13651da177e4SLinus Torvalds unsigned long flags; 13661da177e4SLinus Torvalds 13671da177e4SLinus Torvalds spin_lock_irqsave(&list->lock, flags); 13681da177e4SLinus Torvalds if (skb->list == list) 13691da177e4SLinus Torvalds __skb_unlink(skb, skb->list); 13701da177e4SLinus Torvalds spin_unlock_irqrestore(&list->lock, flags); 13711da177e4SLinus Torvalds } 13721da177e4SLinus Torvalds } 13731da177e4SLinus Torvalds 13741da177e4SLinus Torvalds 13751da177e4SLinus Torvalds /** 13761da177e4SLinus Torvalds * skb_append - append a buffer 13771da177e4SLinus Torvalds * @old: buffer to insert after 13781da177e4SLinus Torvalds * @newsk: buffer to insert 13791da177e4SLinus Torvalds * 13801da177e4SLinus Torvalds * Place a packet after a given packet in a list. The list locks are taken 13811da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls. 13821da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 13831da177e4SLinus Torvalds */ 13841da177e4SLinus Torvalds 13851da177e4SLinus Torvalds void skb_append(struct sk_buff *old, struct sk_buff *newsk) 13861da177e4SLinus Torvalds { 13871da177e4SLinus Torvalds unsigned long flags; 13881da177e4SLinus Torvalds 13891da177e4SLinus Torvalds spin_lock_irqsave(&old->list->lock, flags); 13901da177e4SLinus Torvalds __skb_append(old, newsk); 13911da177e4SLinus Torvalds spin_unlock_irqrestore(&old->list->lock, flags); 13921da177e4SLinus Torvalds } 13931da177e4SLinus Torvalds 13941da177e4SLinus Torvalds 13951da177e4SLinus Torvalds /** 13961da177e4SLinus Torvalds * skb_insert - insert a buffer 13971da177e4SLinus Torvalds * @old: buffer to insert before 13981da177e4SLinus Torvalds * @newsk: buffer to insert 13991da177e4SLinus Torvalds * 14001da177e4SLinus Torvalds * Place a packet before a given packet in a list. The list locks are taken 14011da177e4SLinus Torvalds * and this function is atomic with respect to other list locked calls 14021da177e4SLinus Torvalds * A buffer cannot be placed on two lists at the same time. 14031da177e4SLinus Torvalds */ 14041da177e4SLinus Torvalds 14051da177e4SLinus Torvalds void skb_insert(struct sk_buff *old, struct sk_buff *newsk) 14061da177e4SLinus Torvalds { 14071da177e4SLinus Torvalds unsigned long flags; 14081da177e4SLinus Torvalds 14091da177e4SLinus Torvalds spin_lock_irqsave(&old->list->lock, flags); 14101da177e4SLinus Torvalds __skb_insert(newsk, old->prev, old, old->list); 14111da177e4SLinus Torvalds spin_unlock_irqrestore(&old->list->lock, flags); 14121da177e4SLinus Torvalds } 14131da177e4SLinus Torvalds 14141da177e4SLinus Torvalds #if 0 14151da177e4SLinus Torvalds /* 14161da177e4SLinus Torvalds * Tune the memory allocator for a new MTU size. 14171da177e4SLinus Torvalds */ 14181da177e4SLinus Torvalds void skb_add_mtu(int mtu) 14191da177e4SLinus Torvalds { 14201da177e4SLinus Torvalds /* Must match allocation in alloc_skb */ 14211da177e4SLinus Torvalds mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info); 14221da177e4SLinus Torvalds 14231da177e4SLinus Torvalds kmem_add_cache_size(mtu); 14241da177e4SLinus Torvalds } 14251da177e4SLinus Torvalds #endif 14261da177e4SLinus Torvalds 14271da177e4SLinus Torvalds static inline void skb_split_inside_header(struct sk_buff *skb, 14281da177e4SLinus Torvalds struct sk_buff* skb1, 14291da177e4SLinus Torvalds const u32 len, const int pos) 14301da177e4SLinus Torvalds { 14311da177e4SLinus Torvalds int i; 14321da177e4SLinus Torvalds 14331da177e4SLinus Torvalds memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len); 14341da177e4SLinus Torvalds 14351da177e4SLinus Torvalds /* And move data appendix as is. */ 14361da177e4SLinus Torvalds for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) 14371da177e4SLinus Torvalds skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; 14381da177e4SLinus Torvalds 14391da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; 14401da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 14411da177e4SLinus Torvalds skb1->data_len = skb->data_len; 14421da177e4SLinus Torvalds skb1->len += skb1->data_len; 14431da177e4SLinus Torvalds skb->data_len = 0; 14441da177e4SLinus Torvalds skb->len = len; 14451da177e4SLinus Torvalds skb->tail = skb->data + len; 14461da177e4SLinus Torvalds } 14471da177e4SLinus Torvalds 14481da177e4SLinus Torvalds static inline void skb_split_no_header(struct sk_buff *skb, 14491da177e4SLinus Torvalds struct sk_buff* skb1, 14501da177e4SLinus Torvalds const u32 len, int pos) 14511da177e4SLinus Torvalds { 14521da177e4SLinus Torvalds int i, k = 0; 14531da177e4SLinus Torvalds const int nfrags = skb_shinfo(skb)->nr_frags; 14541da177e4SLinus Torvalds 14551da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags = 0; 14561da177e4SLinus Torvalds skb1->len = skb1->data_len = skb->len - len; 14571da177e4SLinus Torvalds skb->len = len; 14581da177e4SLinus Torvalds skb->data_len = len - pos; 14591da177e4SLinus Torvalds 14601da177e4SLinus Torvalds for (i = 0; i < nfrags; i++) { 14611da177e4SLinus Torvalds int size = skb_shinfo(skb)->frags[i].size; 14621da177e4SLinus Torvalds 14631da177e4SLinus Torvalds if (pos + size > len) { 14641da177e4SLinus Torvalds skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; 14651da177e4SLinus Torvalds 14661da177e4SLinus Torvalds if (pos < len) { 14671da177e4SLinus Torvalds /* Split frag. 14681da177e4SLinus Torvalds * We have two variants in this case: 14691da177e4SLinus Torvalds * 1. Move all the frag to the second 14701da177e4SLinus Torvalds * part, if it is possible. F.e. 14711da177e4SLinus Torvalds * this approach is mandatory for TUX, 14721da177e4SLinus Torvalds * where splitting is expensive. 14731da177e4SLinus Torvalds * 2. Split is accurately. We make this. 14741da177e4SLinus Torvalds */ 14751da177e4SLinus Torvalds get_page(skb_shinfo(skb)->frags[i].page); 14761da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].page_offset += len - pos; 14771da177e4SLinus Torvalds skb_shinfo(skb1)->frags[0].size -= len - pos; 14781da177e4SLinus Torvalds skb_shinfo(skb)->frags[i].size = len - pos; 14791da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 14801da177e4SLinus Torvalds } 14811da177e4SLinus Torvalds k++; 14821da177e4SLinus Torvalds } else 14831da177e4SLinus Torvalds skb_shinfo(skb)->nr_frags++; 14841da177e4SLinus Torvalds pos += size; 14851da177e4SLinus Torvalds } 14861da177e4SLinus Torvalds skb_shinfo(skb1)->nr_frags = k; 14871da177e4SLinus Torvalds } 14881da177e4SLinus Torvalds 14891da177e4SLinus Torvalds /** 14901da177e4SLinus Torvalds * skb_split - Split fragmented skb to two parts at length len. 14911da177e4SLinus Torvalds * @skb: the buffer to split 14921da177e4SLinus Torvalds * @skb1: the buffer to receive the second part 14931da177e4SLinus Torvalds * @len: new length for skb 14941da177e4SLinus Torvalds */ 14951da177e4SLinus Torvalds void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) 14961da177e4SLinus Torvalds { 14971da177e4SLinus Torvalds int pos = skb_headlen(skb); 14981da177e4SLinus Torvalds 14991da177e4SLinus Torvalds if (len < pos) /* Split line is inside header. */ 15001da177e4SLinus Torvalds skb_split_inside_header(skb, skb1, len, pos); 15011da177e4SLinus Torvalds else /* Second chunk has no header, nothing to copy. */ 15021da177e4SLinus Torvalds skb_split_no_header(skb, skb1, len, pos); 15031da177e4SLinus Torvalds } 15041da177e4SLinus Torvalds 15051da177e4SLinus Torvalds void __init skb_init(void) 15061da177e4SLinus Torvalds { 15071da177e4SLinus Torvalds skbuff_head_cache = kmem_cache_create("skbuff_head_cache", 15081da177e4SLinus Torvalds sizeof(struct sk_buff), 15091da177e4SLinus Torvalds 0, 15101da177e4SLinus Torvalds SLAB_HWCACHE_ALIGN, 15111da177e4SLinus Torvalds NULL, NULL); 15121da177e4SLinus Torvalds if (!skbuff_head_cache) 15131da177e4SLinus Torvalds panic("cannot create skbuff cache"); 15141da177e4SLinus Torvalds } 15151da177e4SLinus Torvalds 15161da177e4SLinus Torvalds EXPORT_SYMBOL(___pskb_trim); 15171da177e4SLinus Torvalds EXPORT_SYMBOL(__kfree_skb); 15181da177e4SLinus Torvalds EXPORT_SYMBOL(__pskb_pull_tail); 15191da177e4SLinus Torvalds EXPORT_SYMBOL(alloc_skb); 15201da177e4SLinus Torvalds EXPORT_SYMBOL(pskb_copy); 15211da177e4SLinus Torvalds EXPORT_SYMBOL(pskb_expand_head); 15221da177e4SLinus Torvalds EXPORT_SYMBOL(skb_checksum); 15231da177e4SLinus Torvalds EXPORT_SYMBOL(skb_clone); 15241da177e4SLinus Torvalds EXPORT_SYMBOL(skb_clone_fraglist); 15251da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy); 15261da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_and_csum_bits); 15271da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_and_csum_dev); 15281da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_bits); 15291da177e4SLinus Torvalds EXPORT_SYMBOL(skb_copy_expand); 15301da177e4SLinus Torvalds EXPORT_SYMBOL(skb_over_panic); 15311da177e4SLinus Torvalds EXPORT_SYMBOL(skb_pad); 15321da177e4SLinus Torvalds EXPORT_SYMBOL(skb_realloc_headroom); 15331da177e4SLinus Torvalds EXPORT_SYMBOL(skb_under_panic); 15341da177e4SLinus Torvalds EXPORT_SYMBOL(skb_dequeue); 15351da177e4SLinus Torvalds EXPORT_SYMBOL(skb_dequeue_tail); 15361da177e4SLinus Torvalds EXPORT_SYMBOL(skb_insert); 15371da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_purge); 15381da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_head); 15391da177e4SLinus Torvalds EXPORT_SYMBOL(skb_queue_tail); 15401da177e4SLinus Torvalds EXPORT_SYMBOL(skb_unlink); 15411da177e4SLinus Torvalds EXPORT_SYMBOL(skb_append); 15421da177e4SLinus Torvalds EXPORT_SYMBOL(skb_split); 1543