blob: e561f9f07d6daa3a13de919334699cc9b82773a7 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Routines having to do with the 'struct sk_buff' memory handlers.
3 *
Alan Cox113aa832008-10-13 19:01:08 -07004 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 * Florian La Roche <rzsfl@rz.uni-sb.de>
6 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * Fixes:
8 * Alan Cox : Fixed the worst of the load
9 * balancer bugs.
10 * Dave Platt : Interrupt stacking fix.
11 * Richard Kooijman : Timestamp fixes.
12 * Alan Cox : Changed buffer format.
13 * Alan Cox : destructor hook for AF_UNIX etc.
14 * Linus Torvalds : Better skb_clone.
15 * Alan Cox : Added skb_copy.
16 * Alan Cox : Added all the changed routines Linus
17 * only put in the headers
18 * Ray VanTassle : Fixed --skb->lock in free
19 * Alan Cox : skb_copy copy arp field
20 * Andi Kleen : slabified it.
21 * Robert Olsson : Removed skb_head_pool
22 *
23 * NOTE:
24 * The __skb_ routines should be called with interrupts
25 * disabled, or you better be *real* sure that the operation is atomic
26 * with respect to whatever list is being frobbed (e.g. via lock_sock()
27 * or via disabling bottom half handlers, etc).
28 *
29 * This program is free software; you can redistribute it and/or
30 * modify it under the terms of the GNU General Public License
31 * as published by the Free Software Foundation; either version
32 * 2 of the License, or (at your option) any later version.
33 */
34
35/*
36 * The functions in this file will not compile correctly with gcc 2.4.x
37 */
38
Joe Perchese005d192012-05-16 19:58:40 +000039#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <linux/module.h>
42#include <linux/types.h>
43#include <linux/kernel.h>
Vegard Nossumfe55f6d2008-08-30 12:16:35 +020044#include <linux/kmemcheck.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#include <linux/mm.h>
46#include <linux/interrupt.h>
47#include <linux/in.h>
48#include <linux/inet.h>
49#include <linux/slab.h>
Florian Westphalde960aa2014-01-26 10:58:16 +010050#include <linux/tcp.h>
51#include <linux/udp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052#include <linux/netdevice.h>
53#ifdef CONFIG_NET_CLS_ACT
54#include <net/pkt_sched.h>
55#endif
56#include <linux/string.h>
57#include <linux/skbuff.h>
Jens Axboe9c55e012007-11-06 23:30:13 -080058#include <linux/splice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#include <linux/cache.h>
60#include <linux/rtnetlink.h>
61#include <linux/init.h>
David Howells716ea3a2007-04-02 20:19:53 -070062#include <linux/scatterlist.h>
Patrick Ohlyac45f602009-02-12 05:03:37 +000063#include <linux/errqueue.h>
Linus Torvalds268bb0c2011-05-20 12:50:29 -070064#include <linux/prefetch.h>
Vlad Yasevich0d5501c2014-08-08 14:42:13 -040065#include <linux/if_vlan.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67#include <net/protocol.h>
68#include <net/dst.h>
69#include <net/sock.h>
70#include <net/checksum.h>
Paul Durranted1f50c2014-01-09 10:02:46 +000071#include <net/ip6_checksum.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070072#include <net/xfrm.h>
73
74#include <asm/uaccess.h>
Steven Rostedtad8d75f2009-04-14 19:39:12 -040075#include <trace/events/skb.h>
Eric Dumazet51c56b02012-04-05 11:35:15 +020076#include <linux/highmem.h>
Willem de Bruijnb245be12015-01-30 13:29:32 -050077#include <linux/capability.h>
78#include <linux/user_namespace.h>
Al Viroa1f8e7f72006-10-19 16:08:53 -040079
Eric Dumazetd7e88832012-04-30 08:10:34 +000080struct kmem_cache *skbuff_head_cache __read_mostly;
Christoph Lametere18b8902006-12-06 20:33:20 -080081static struct kmem_cache *skbuff_fclone_cache __read_mostly;
Hans Westgaard Ry5f74f822016-02-03 09:26:57 +010082int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
83EXPORT_SYMBOL(sysctl_max_skb_frags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Linus Torvalds1da177e2005-04-16 15:20:36 -070085/**
Jean Sacrenf05de732013-02-11 13:30:38 +000086 * skb_panic - private function for out-of-line support
87 * @skb: buffer
88 * @sz: size
89 * @addr: address
James Hogan99d58512013-02-13 11:20:27 +000090 * @msg: skb_over_panic or skb_under_panic
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 *
Jean Sacrenf05de732013-02-11 13:30:38 +000092 * Out-of-line support for skb_put() and skb_push().
93 * Called via the wrapper skb_over_panic() or skb_under_panic().
94 * Keep out of line to prevent kernel bloat.
95 * __builtin_return_address is not used because it is not always reliable.
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 */
Jean Sacrenf05de732013-02-11 13:30:38 +000097static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
James Hogan99d58512013-02-13 11:20:27 +000098 const char msg[])
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
Joe Perchese005d192012-05-16 19:58:40 +0000100 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
James Hogan99d58512013-02-13 11:20:27 +0000101 msg, addr, skb->len, sz, skb->head, skb->data,
Joe Perchese005d192012-05-16 19:58:40 +0000102 (unsigned long)skb->tail, (unsigned long)skb->end,
103 skb->dev ? skb->dev->name : "<NULL>");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 BUG();
105}
106
Jean Sacrenf05de732013-02-11 13:30:38 +0000107static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
Jean Sacrenf05de732013-02-11 13:30:38 +0000109 skb_panic(skb, sz, addr, __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110}
111
Jean Sacrenf05de732013-02-11 13:30:38 +0000112static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
113{
114 skb_panic(skb, sz, addr, __func__);
115}
Mel Gormanc93bdd02012-07-31 16:44:19 -0700116
117/*
118 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
119 * the caller if emergency pfmemalloc reserves are being used. If it is and
120 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
121 * may be used. Otherwise, the packet data may be discarded until enough
122 * memory is free
123 */
124#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
125 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
stephen hemminger61c5e882012-12-28 18:24:28 +0000126
127static void *__kmalloc_reserve(size_t size, gfp_t flags, int node,
128 unsigned long ip, bool *pfmemalloc)
Mel Gormanc93bdd02012-07-31 16:44:19 -0700129{
130 void *obj;
131 bool ret_pfmemalloc = false;
132
133 /*
134 * Try a regular allocation, when that fails and we're not entitled
135 * to the reserves, fail.
136 */
137 obj = kmalloc_node_track_caller(size,
138 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
139 node);
140 if (obj || !(gfp_pfmemalloc_allowed(flags)))
141 goto out;
142
143 /* Try again but now we are using pfmemalloc reserves */
144 ret_pfmemalloc = true;
145 obj = kmalloc_node_track_caller(size, flags, node);
146
147out:
148 if (pfmemalloc)
149 *pfmemalloc = ret_pfmemalloc;
150
151 return obj;
152}
153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154/* Allocate a new skbuff. We do this ourselves so we can fill in a few
155 * 'private' fields and also do memory statistics to find all the
156 * [BEEP] leaks.
157 *
158 */
159
Patrick McHardy0ebd0ac2013-04-17 06:46:58 +0000160struct sk_buff *__alloc_skb_head(gfp_t gfp_mask, int node)
161{
162 struct sk_buff *skb;
163
164 /* Get the HEAD */
165 skb = kmem_cache_alloc_node(skbuff_head_cache,
166 gfp_mask & ~__GFP_DMA, node);
167 if (!skb)
168 goto out;
169
170 /*
171 * Only clear those fields we need to clear, not those that we will
172 * actually initialise below. Hence, don't put any more fields after
173 * the tail pointer in struct sk_buff!
174 */
175 memset(skb, 0, offsetof(struct sk_buff, tail));
Pablo Neira5e71d9d2013-06-03 09:28:43 +0000176 skb->head = NULL;
Patrick McHardy0ebd0ac2013-04-17 06:46:58 +0000177 skb->truesize = sizeof(struct sk_buff);
178 atomic_set(&skb->users, 1);
179
Cong Wang35d04612013-05-29 15:16:05 +0800180 skb->mac_header = (typeof(skb->mac_header))~0U;
Patrick McHardy0ebd0ac2013-04-17 06:46:58 +0000181out:
182 return skb;
183}
184
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185/**
David S. Millerd179cd12005-08-17 14:57:30 -0700186 * __alloc_skb - allocate a network buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 * @size: size to allocate
188 * @gfp_mask: allocation mask
Mel Gormanc93bdd02012-07-31 16:44:19 -0700189 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
190 * instead of head cache and allocate a cloned (child) skb.
191 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
192 * allocations in case the data is required for writeback
Christoph Hellwigb30973f2006-12-06 20:32:36 -0800193 * @node: numa node to allocate memory on
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 *
195 * Allocate a new &sk_buff. The returned buffer has no headroom and a
Ben Hutchings94b60422012-06-06 15:23:37 +0000196 * tail room of at least size bytes. The object has a reference count
197 * of one. The return is the buffer. On a failure the return is %NULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 *
199 * Buffers may only be allocated from interrupts using a @gfp_mask of
200 * %GFP_ATOMIC.
201 */
Al Virodd0fc662005-10-07 07:46:04 +0100202struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
Mel Gormanc93bdd02012-07-31 16:44:19 -0700203 int flags, int node)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204{
Christoph Lametere18b8902006-12-06 20:33:20 -0800205 struct kmem_cache *cache;
Benjamin LaHaise4947d3e2006-01-03 14:06:50 -0800206 struct skb_shared_info *shinfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 struct sk_buff *skb;
208 u8 *data;
Mel Gormanc93bdd02012-07-31 16:44:19 -0700209 bool pfmemalloc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
Mel Gormanc93bdd02012-07-31 16:44:19 -0700211 cache = (flags & SKB_ALLOC_FCLONE)
212 ? skbuff_fclone_cache : skbuff_head_cache;
213
214 if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
215 gfp_mask |= __GFP_MEMALLOC;
Herbert Xu8798b3f2006-01-23 16:32:45 -0800216
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 /* Get the HEAD */
Christoph Hellwigb30973f2006-12-06 20:32:36 -0800218 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (!skb)
220 goto out;
Eric Dumazetec7d2f22010-05-05 01:07:37 -0700221 prefetchw(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
Eric Dumazet87fb4b72011-10-13 07:28:54 +0000223 /* We do our best to align skb_shared_info on a separate cache
224 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
225 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
226 * Both skb->head and skb_shared_info are cache line aligned.
227 */
Tony Lindgrenbc417e32011-11-02 13:40:28 +0000228 size = SKB_DATA_ALIGN(size);
Eric Dumazet87fb4b72011-10-13 07:28:54 +0000229 size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
Mel Gormanc93bdd02012-07-31 16:44:19 -0700230 data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 if (!data)
232 goto nodata;
Eric Dumazet87fb4b72011-10-13 07:28:54 +0000233 /* kmalloc(size) might give us more room than requested.
234 * Put skb_shared_info exactly at the end of allocated zone,
235 * to allow max possible filling before reallocation.
236 */
237 size = SKB_WITH_OVERHEAD(ksize(data));
Eric Dumazetec7d2f22010-05-05 01:07:37 -0700238 prefetchw(data + size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
Arnaldo Carvalho de Meloca0605a2007-03-19 10:48:59 -0300240 /*
Johannes Bergc8005782008-05-03 20:56:42 -0700241 * Only clear those fields we need to clear, not those that we will
242 * actually initialise below. Hence, don't put any more fields after
243 * the tail pointer in struct sk_buff!
Arnaldo Carvalho de Meloca0605a2007-03-19 10:48:59 -0300244 */
245 memset(skb, 0, offsetof(struct sk_buff, tail));
Eric Dumazet87fb4b72011-10-13 07:28:54 +0000246 /* Account for allocated memory : skb + skb->head */
247 skb->truesize = SKB_TRUESIZE(size);
Mel Gormanc93bdd02012-07-31 16:44:19 -0700248 skb->pfmemalloc = pfmemalloc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 atomic_set(&skb->users, 1);
250 skb->head = data;
251 skb->data = data;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700252 skb_reset_tail_pointer(skb);
Arnaldo Carvalho de Melo4305b542007-04-19 20:43:29 -0700253 skb->end = skb->tail + size;
Cong Wang35d04612013-05-29 15:16:05 +0800254 skb->mac_header = (typeof(skb->mac_header))~0U;
255 skb->transport_header = (typeof(skb->transport_header))~0U;
Stephen Hemminger19633e12009-06-17 05:23:27 +0000256
Benjamin LaHaise4947d3e2006-01-03 14:06:50 -0800257 /* make sure we initialize shinfo sequentially */
258 shinfo = skb_shinfo(skb);
Eric Dumazetec7d2f22010-05-05 01:07:37 -0700259 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
Benjamin LaHaise4947d3e2006-01-03 14:06:50 -0800260 atomic_set(&shinfo->dataref, 1);
Eric Dumazetc2aa3662011-01-25 23:18:38 +0000261 kmemcheck_annotate_variable(shinfo->destructor_arg);
Benjamin LaHaise4947d3e2006-01-03 14:06:50 -0800262
Mel Gormanc93bdd02012-07-31 16:44:19 -0700263 if (flags & SKB_ALLOC_FCLONE) {
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700264 struct sk_buff_fclones *fclones;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700266 fclones = container_of(skb, struct sk_buff_fclones, skb1);
267
268 kmemcheck_annotate_bitfield(&fclones->skb2, flags1);
David S. Millerd179cd12005-08-17 14:57:30 -0700269 skb->fclone = SKB_FCLONE_ORIG;
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700270 atomic_set(&fclones->fclone_ref, 1);
David S. Millerd179cd12005-08-17 14:57:30 -0700271
Eric Dumazet6ffe75e2014-12-03 17:04:39 -0800272 fclones->skb2.fclone = SKB_FCLONE_CLONE;
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700273 fclones->skb2.pfmemalloc = pfmemalloc;
David S. Millerd179cd12005-08-17 14:57:30 -0700274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275out:
276 return skb;
277nodata:
Herbert Xu8798b3f2006-01-23 16:32:45 -0800278 kmem_cache_free(cache, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 skb = NULL;
280 goto out;
281}
David S. Millerb4ac530fc2009-02-10 02:09:24 -0800282EXPORT_SYMBOL(__alloc_skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
284/**
Eric Dumazet2ea2f622015-04-24 16:05:01 -0700285 * __build_skb - build a network buffer
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000286 * @data: data buffer provided by caller
Eric Dumazet2ea2f622015-04-24 16:05:01 -0700287 * @frag_size: size of data, or 0 if head was kmalloced
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000288 *
289 * Allocate a new &sk_buff. Caller provides space holding head and
Florian Fainellideceb4c2013-07-23 20:22:39 +0100290 * skb_shared_info. @data must have been allocated by kmalloc() only if
Eric Dumazet2ea2f622015-04-24 16:05:01 -0700291 * @frag_size is 0, otherwise data should come from the page allocator
292 * or vmalloc()
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000293 * The return is the new skb buffer.
294 * On a failure the return is %NULL, and @data is not freed.
295 * Notes :
296 * Before IO, driver allocates only data buffer where NIC put incoming frame
297 * Driver should add room at head (NET_SKB_PAD) and
298 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
299 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
300 * before giving packet to stack.
301 * RX rings only contains data buffers, not full skbs.
302 */
Eric Dumazet2ea2f622015-04-24 16:05:01 -0700303struct sk_buff *__build_skb(void *data, unsigned int frag_size)
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000304{
305 struct skb_shared_info *shinfo;
306 struct sk_buff *skb;
Eric Dumazetd3836f22012-04-27 00:33:38 +0000307 unsigned int size = frag_size ? : ksize(data);
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000308
309 skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
310 if (!skb)
311 return NULL;
312
Eric Dumazetd3836f22012-04-27 00:33:38 +0000313 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000314
315 memset(skb, 0, offsetof(struct sk_buff, tail));
316 skb->truesize = SKB_TRUESIZE(size);
317 atomic_set(&skb->users, 1);
318 skb->head = data;
319 skb->data = data;
320 skb_reset_tail_pointer(skb);
321 skb->end = skb->tail + size;
Cong Wang35d04612013-05-29 15:16:05 +0800322 skb->mac_header = (typeof(skb->mac_header))~0U;
323 skb->transport_header = (typeof(skb->transport_header))~0U;
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000324
325 /* make sure we initialize shinfo sequentially */
326 shinfo = skb_shinfo(skb);
327 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
328 atomic_set(&shinfo->dataref, 1);
329 kmemcheck_annotate_variable(shinfo->destructor_arg);
330
331 return skb;
332}
Eric Dumazet2ea2f622015-04-24 16:05:01 -0700333
334/* build_skb() is wrapper over __build_skb(), that specifically
335 * takes care of skb->head and skb->pfmemalloc
336 * This means that if @frag_size is not zero, then @data must be backed
337 * by a page fragment, not kmalloc() or vmalloc()
338 */
339struct sk_buff *build_skb(void *data, unsigned int frag_size)
340{
341 struct sk_buff *skb = __build_skb(data, frag_size);
342
343 if (skb && frag_size) {
344 skb->head_frag = 1;
Michal Hocko2f064f32015-08-21 14:11:51 -0700345 if (page_is_pfmemalloc(virt_to_head_page(data)))
Eric Dumazet2ea2f622015-04-24 16:05:01 -0700346 skb->pfmemalloc = 1;
347 }
348 return skb;
349}
Eric Dumazetb2b5ce92011-11-14 06:03:34 +0000350EXPORT_SYMBOL(build_skb);
351
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100352#define NAPI_SKB_CACHE_SIZE 64
353
354struct napi_alloc_cache {
355 struct page_frag_cache page;
356 size_t skb_count;
357 void *skb_cache[NAPI_SKB_CACHE_SIZE];
358};
359
Alexander Duyckb63ae8c2015-05-06 21:11:57 -0700360static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100361static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache);
Alexander Duyckffde7322014-12-09 19:40:42 -0800362
363static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
364{
Alexander Duyckb63ae8c2015-05-06 21:11:57 -0700365 struct page_frag_cache *nc;
Alexander Duyckffde7322014-12-09 19:40:42 -0800366 unsigned long flags;
367 void *data;
368
369 local_irq_save(flags);
Alexander Duyck94519802015-05-06 21:11:40 -0700370 nc = this_cpu_ptr(&netdev_alloc_cache);
371 data = __alloc_page_frag(nc, fragsz, gfp_mask);
Eric Dumazet6f532612012-05-18 05:12:12 +0000372 local_irq_restore(flags);
373 return data;
374}
Mel Gormanc93bdd02012-07-31 16:44:19 -0700375
376/**
377 * netdev_alloc_frag - allocate a page fragment
378 * @fragsz: fragment size
379 *
380 * Allocates a frag from a page for receive buffer.
381 * Uses GFP_ATOMIC allocations.
382 */
383void *netdev_alloc_frag(unsigned int fragsz)
384{
385 return __netdev_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
386}
Eric Dumazet6f532612012-05-18 05:12:12 +0000387EXPORT_SYMBOL(netdev_alloc_frag);
388
Alexander Duyckffde7322014-12-09 19:40:42 -0800389static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
390{
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100391 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
Alexander Duyck94519802015-05-06 21:11:40 -0700392
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100393 return __alloc_page_frag(&nc->page, fragsz, gfp_mask);
Alexander Duyckffde7322014-12-09 19:40:42 -0800394}
395
396void *napi_alloc_frag(unsigned int fragsz)
397{
398 return __napi_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
399}
400EXPORT_SYMBOL(napi_alloc_frag);
401
Eric Dumazet6f532612012-05-18 05:12:12 +0000402/**
Alexander Duyckfd11a832014-12-09 19:40:49 -0800403 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
404 * @dev: network device to receive on
Masanari Iidad7499162015-08-24 22:56:54 +0900405 * @len: length to allocate
Alexander Duyckfd11a832014-12-09 19:40:49 -0800406 * @gfp_mask: get_free_pages mask, passed to alloc_skb
407 *
408 * Allocate a new &sk_buff and assign it a usage count of one. The
409 * buffer has NET_SKB_PAD headroom built in. Users should allocate
410 * the headroom they think they need without accounting for the
411 * built in space. The built in space is used for optimisations.
412 *
413 * %NULL is returned if there is no free memory.
414 */
Alexander Duyck94519802015-05-06 21:11:40 -0700415struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
416 gfp_t gfp_mask)
Alexander Duyckfd11a832014-12-09 19:40:49 -0800417{
Alexander Duyckb63ae8c2015-05-06 21:11:57 -0700418 struct page_frag_cache *nc;
Alexander Duyck94519802015-05-06 21:11:40 -0700419 unsigned long flags;
Alexander Duyckfd11a832014-12-09 19:40:49 -0800420 struct sk_buff *skb;
Alexander Duyck94519802015-05-06 21:11:40 -0700421 bool pfmemalloc;
422 void *data;
Alexander Duyckfd11a832014-12-09 19:40:49 -0800423
Alexander Duyck94519802015-05-06 21:11:40 -0700424 len += NET_SKB_PAD;
Alexander Duyckfd11a832014-12-09 19:40:49 -0800425
Alexander Duyck94519802015-05-06 21:11:40 -0700426 if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) ||
Mel Gormand0164ad2015-11-06 16:28:21 -0800427 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
Alexander Duycka080e7b2015-05-13 13:34:13 -0700428 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
429 if (!skb)
430 goto skb_fail;
431 goto skb_success;
432 }
Alexander Duyck94519802015-05-06 21:11:40 -0700433
434 len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
435 len = SKB_DATA_ALIGN(len);
436
437 if (sk_memalloc_socks())
438 gfp_mask |= __GFP_MEMALLOC;
439
440 local_irq_save(flags);
441
442 nc = this_cpu_ptr(&netdev_alloc_cache);
443 data = __alloc_page_frag(nc, len, gfp_mask);
444 pfmemalloc = nc->pfmemalloc;
445
446 local_irq_restore(flags);
447
448 if (unlikely(!data))
449 return NULL;
450
451 skb = __build_skb(data, len);
452 if (unlikely(!skb)) {
Alexander Duyck181edb22015-05-06 21:12:03 -0700453 skb_free_frag(data);
Alexander Duyck94519802015-05-06 21:11:40 -0700454 return NULL;
Christoph Hellwig7b2e4972006-08-07 16:09:04 -0700455 }
Alexander Duyckfd11a832014-12-09 19:40:49 -0800456
Alexander Duyck94519802015-05-06 21:11:40 -0700457 /* use OR instead of assignment to avoid clearing of bits in mask */
458 if (pfmemalloc)
459 skb->pfmemalloc = 1;
460 skb->head_frag = 1;
461
Alexander Duycka080e7b2015-05-13 13:34:13 -0700462skb_success:
Alexander Duyck94519802015-05-06 21:11:40 -0700463 skb_reserve(skb, NET_SKB_PAD);
464 skb->dev = dev;
465
Alexander Duycka080e7b2015-05-13 13:34:13 -0700466skb_fail:
Christoph Hellwig8af27452006-07-31 22:35:23 -0700467 return skb;
468}
David S. Millerb4ac530fc2009-02-10 02:09:24 -0800469EXPORT_SYMBOL(__netdev_alloc_skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470
Alexander Duyckfd11a832014-12-09 19:40:49 -0800471/**
472 * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
473 * @napi: napi instance this buffer was allocated for
Masanari Iidad7499162015-08-24 22:56:54 +0900474 * @len: length to allocate
Alexander Duyckfd11a832014-12-09 19:40:49 -0800475 * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
476 *
477 * Allocate a new sk_buff for use in NAPI receive. This buffer will
478 * attempt to allocate the head from a special reserved region used
479 * only for NAPI Rx allocation. By doing this we can save several
480 * CPU cycles by avoiding having to disable and re-enable IRQs.
481 *
482 * %NULL is returned if there is no free memory.
483 */
Alexander Duyck94519802015-05-06 21:11:40 -0700484struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
485 gfp_t gfp_mask)
Alexander Duyckfd11a832014-12-09 19:40:49 -0800486{
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100487 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
Alexander Duyckfd11a832014-12-09 19:40:49 -0800488 struct sk_buff *skb;
Alexander Duyck94519802015-05-06 21:11:40 -0700489 void *data;
Alexander Duyckfd11a832014-12-09 19:40:49 -0800490
Alexander Duyck94519802015-05-06 21:11:40 -0700491 len += NET_SKB_PAD + NET_IP_ALIGN;
Alexander Duyckfd11a832014-12-09 19:40:49 -0800492
Alexander Duyck94519802015-05-06 21:11:40 -0700493 if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) ||
Mel Gormand0164ad2015-11-06 16:28:21 -0800494 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
Alexander Duycka080e7b2015-05-13 13:34:13 -0700495 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
496 if (!skb)
497 goto skb_fail;
498 goto skb_success;
499 }
Alexander Duyck94519802015-05-06 21:11:40 -0700500
501 len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
502 len = SKB_DATA_ALIGN(len);
503
504 if (sk_memalloc_socks())
505 gfp_mask |= __GFP_MEMALLOC;
506
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100507 data = __alloc_page_frag(&nc->page, len, gfp_mask);
Alexander Duyck94519802015-05-06 21:11:40 -0700508 if (unlikely(!data))
509 return NULL;
510
511 skb = __build_skb(data, len);
512 if (unlikely(!skb)) {
Alexander Duyck181edb22015-05-06 21:12:03 -0700513 skb_free_frag(data);
Alexander Duyck94519802015-05-06 21:11:40 -0700514 return NULL;
Alexander Duyckfd11a832014-12-09 19:40:49 -0800515 }
516
Alexander Duyck94519802015-05-06 21:11:40 -0700517 /* use OR instead of assignment to avoid clearing of bits in mask */
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100518 if (nc->page.pfmemalloc)
Alexander Duyck94519802015-05-06 21:11:40 -0700519 skb->pfmemalloc = 1;
520 skb->head_frag = 1;
521
Alexander Duycka080e7b2015-05-13 13:34:13 -0700522skb_success:
Alexander Duyck94519802015-05-06 21:11:40 -0700523 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
524 skb->dev = napi->dev;
525
Alexander Duycka080e7b2015-05-13 13:34:13 -0700526skb_fail:
Alexander Duyckfd11a832014-12-09 19:40:49 -0800527 return skb;
528}
529EXPORT_SYMBOL(__napi_alloc_skb);
530
Peter Zijlstra654bed12008-10-07 14:22:33 -0700531void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
Eric Dumazet50269e12012-03-23 23:59:33 +0000532 int size, unsigned int truesize)
Peter Zijlstra654bed12008-10-07 14:22:33 -0700533{
534 skb_fill_page_desc(skb, i, page, off, size);
535 skb->len += size;
536 skb->data_len += size;
Eric Dumazet50269e12012-03-23 23:59:33 +0000537 skb->truesize += truesize;
Peter Zijlstra654bed12008-10-07 14:22:33 -0700538}
539EXPORT_SYMBOL(skb_add_rx_frag);
540
Jason Wangf8e617e2013-11-01 14:07:47 +0800541void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
542 unsigned int truesize)
543{
544 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
545
546 skb_frag_size_add(frag, size);
547 skb->len += size;
548 skb->data_len += size;
549 skb->truesize += truesize;
550}
551EXPORT_SYMBOL(skb_coalesce_rx_frag);
552
Herbert Xu27b437c2006-07-13 19:26:39 -0700553static void skb_drop_list(struct sk_buff **listp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554{
Eric Dumazetbd8a7032013-06-24 06:26:00 -0700555 kfree_skb_list(*listp);
Herbert Xu27b437c2006-07-13 19:26:39 -0700556 *listp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557}
558
Herbert Xu27b437c2006-07-13 19:26:39 -0700559static inline void skb_drop_fraglist(struct sk_buff *skb)
560{
561 skb_drop_list(&skb_shinfo(skb)->frag_list);
562}
563
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564static void skb_clone_fraglist(struct sk_buff *skb)
565{
566 struct sk_buff *list;
567
David S. Millerfbb398a2009-06-09 00:18:59 -0700568 skb_walk_frags(skb, list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 skb_get(list);
570}
571
Eric Dumazetd3836f22012-04-27 00:33:38 +0000572static void skb_free_head(struct sk_buff *skb)
573{
Alexander Duyck181edb22015-05-06 21:12:03 -0700574 unsigned char *head = skb->head;
575
Eric Dumazetd3836f22012-04-27 00:33:38 +0000576 if (skb->head_frag)
Alexander Duyck181edb22015-05-06 21:12:03 -0700577 skb_free_frag(head);
Eric Dumazetd3836f22012-04-27 00:33:38 +0000578 else
Alexander Duyck181edb22015-05-06 21:12:03 -0700579 kfree(head);
Eric Dumazetd3836f22012-04-27 00:33:38 +0000580}
581
Adrian Bunk5bba1712006-06-29 13:02:35 -0700582static void skb_release_data(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583{
Eric Dumazetff04a772014-09-23 18:39:30 -0700584 struct skb_shared_info *shinfo = skb_shinfo(skb);
585 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
Eric Dumazetff04a772014-09-23 18:39:30 -0700587 if (skb->cloned &&
588 atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
589 &shinfo->dataref))
590 return;
Shirley Maa6686f22011-07-06 12:22:12 +0000591
Eric Dumazetff04a772014-09-23 18:39:30 -0700592 for (i = 0; i < shinfo->nr_frags; i++)
593 __skb_frag_unref(&shinfo->frags[i]);
Shirley Maa6686f22011-07-06 12:22:12 +0000594
Eric Dumazetff04a772014-09-23 18:39:30 -0700595 /*
596 * If skb buf is from userspace, we need to notify the caller
597 * the lower device DMA has done;
598 */
599 if (shinfo->tx_flags & SKBTX_DEV_ZEROCOPY) {
600 struct ubuf_info *uarg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601
Eric Dumazetff04a772014-09-23 18:39:30 -0700602 uarg = shinfo->destructor_arg;
603 if (uarg->callback)
604 uarg->callback(uarg, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 }
Eric Dumazetff04a772014-09-23 18:39:30 -0700606
607 if (shinfo->frag_list)
608 kfree_skb_list(shinfo->frag_list);
609
610 skb_free_head(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611}
612
613/*
614 * Free an skbuff by memory without cleaning the state.
615 */
Herbert Xu2d4baff2007-11-26 23:11:19 +0800616static void kfree_skbmem(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617{
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700618 struct sk_buff_fclones *fclones;
David S. Millerd179cd12005-08-17 14:57:30 -0700619
David S. Millerd179cd12005-08-17 14:57:30 -0700620 switch (skb->fclone) {
621 case SKB_FCLONE_UNAVAILABLE:
622 kmem_cache_free(skbuff_head_cache, skb);
Eric Dumazet6ffe75e2014-12-03 17:04:39 -0800623 return;
David S. Millerd179cd12005-08-17 14:57:30 -0700624
625 case SKB_FCLONE_ORIG:
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700626 fclones = container_of(skb, struct sk_buff_fclones, skb1);
Eric Dumazet6ffe75e2014-12-03 17:04:39 -0800627
628 /* We usually free the clone (TX completion) before original skb
629 * This test would have no chance to be true for the clone,
630 * while here, branch prediction will be good.
631 */
632 if (atomic_read(&fclones->fclone_ref) == 1)
633 goto fastpath;
David S. Millerd179cd12005-08-17 14:57:30 -0700634 break;
635
Eric Dumazet6ffe75e2014-12-03 17:04:39 -0800636 default: /* SKB_FCLONE_CLONE */
Eric Dumazetd0bf4a92014-09-29 13:29:15 -0700637 fclones = container_of(skb, struct sk_buff_fclones, skb2);
David S. Millerd179cd12005-08-17 14:57:30 -0700638 break;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -0700639 }
Eric Dumazet6ffe75e2014-12-03 17:04:39 -0800640 if (!atomic_dec_and_test(&fclones->fclone_ref))
641 return;
642fastpath:
643 kmem_cache_free(skbuff_fclone_cache, fclones);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644}
645
Lennert Buytenhek04a4bb52008-10-01 02:33:12 -0700646static void skb_release_head_state(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647{
Eric Dumazetadf30902009-06-02 05:19:30 +0000648 skb_dst_drop(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649#ifdef CONFIG_XFRM
650 secpath_put(skb->sp);
651#endif
Stephen Hemminger9c2b3322005-04-19 22:39:42 -0700652 if (skb->destructor) {
653 WARN_ON(in_irq());
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 skb->destructor(skb);
655 }
Igor Maravića3bf7ae2011-12-12 02:58:22 +0000656#if IS_ENABLED(CONFIG_NF_CONNTRACK)
Yasuyuki Kozakai5f79e0f2007-03-23 11:17:07 -0700657 nf_conntrack_put(skb->nfct);
KOVACS Krisztian2fc72c72011-01-12 20:25:08 +0100658#endif
Pablo Neira Ayuso1109a902014-10-01 11:19:17 +0200659#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 nf_bridge_put(skb->nf_bridge);
661#endif
Lennert Buytenhek04a4bb52008-10-01 02:33:12 -0700662}
663
664/* Free everything but the sk_buff shell. */
665static void skb_release_all(struct sk_buff *skb)
666{
667 skb_release_head_state(skb);
Pablo Neira5e71d9d2013-06-03 09:28:43 +0000668 if (likely(skb->head))
Patrick McHardy0ebd0ac2013-04-17 06:46:58 +0000669 skb_release_data(skb);
Herbert Xu2d4baff2007-11-26 23:11:19 +0800670}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
Herbert Xu2d4baff2007-11-26 23:11:19 +0800672/**
673 * __kfree_skb - private function
674 * @skb: buffer
675 *
676 * Free an sk_buff. Release anything attached to the buffer.
677 * Clean the state. This is an internal helper function. Users should
678 * always call kfree_skb
679 */
680
681void __kfree_skb(struct sk_buff *skb)
682{
683 skb_release_all(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 kfree_skbmem(skb);
685}
David S. Millerb4ac530fc2009-02-10 02:09:24 -0800686EXPORT_SYMBOL(__kfree_skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687
688/**
Jörn Engel231d06a2006-03-20 21:28:35 -0800689 * kfree_skb - free an sk_buff
690 * @skb: buffer to free
691 *
692 * Drop a reference to the buffer and free it if the usage count has
693 * hit zero.
694 */
695void kfree_skb(struct sk_buff *skb)
696{
697 if (unlikely(!skb))
698 return;
699 if (likely(atomic_read(&skb->users) == 1))
700 smp_rmb();
701 else if (likely(!atomic_dec_and_test(&skb->users)))
702 return;
Neil Hormanead2ceb2009-03-11 09:49:55 +0000703 trace_kfree_skb(skb, __builtin_return_address(0));
Jörn Engel231d06a2006-03-20 21:28:35 -0800704 __kfree_skb(skb);
705}
David S. Millerb4ac530fc2009-02-10 02:09:24 -0800706EXPORT_SYMBOL(kfree_skb);
Jörn Engel231d06a2006-03-20 21:28:35 -0800707
Eric Dumazetbd8a7032013-06-24 06:26:00 -0700708void kfree_skb_list(struct sk_buff *segs)
709{
710 while (segs) {
711 struct sk_buff *next = segs->next;
712
713 kfree_skb(segs);
714 segs = next;
715 }
716}
717EXPORT_SYMBOL(kfree_skb_list);
718
Stephen Hemmingerd1a203e2008-11-01 21:01:09 -0700719/**
Michael S. Tsirkin25121172012-11-01 09:16:28 +0000720 * skb_tx_error - report an sk_buff xmit error
721 * @skb: buffer that triggered an error
722 *
723 * Report xmit error if a device callback is tracking this skb.
724 * skb must be freed afterwards.
725 */
726void skb_tx_error(struct sk_buff *skb)
727{
728 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
729 struct ubuf_info *uarg;
730
731 uarg = skb_shinfo(skb)->destructor_arg;
732 if (uarg->callback)
733 uarg->callback(uarg, false);
734 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
735 }
736}
737EXPORT_SYMBOL(skb_tx_error);
738
739/**
Neil Hormanead2ceb2009-03-11 09:49:55 +0000740 * consume_skb - free an skbuff
741 * @skb: buffer to free
742 *
743 * Drop a ref to the buffer and free it if the usage count has hit zero
744 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
745 * is being dropped after a failure and notes that
746 */
747void consume_skb(struct sk_buff *skb)
748{
749 if (unlikely(!skb))
750 return;
751 if (likely(atomic_read(&skb->users) == 1))
752 smp_rmb();
753 else if (likely(!atomic_dec_and_test(&skb->users)))
754 return;
Koki Sanagi07dc22e2010-08-23 18:46:12 +0900755 trace_consume_skb(skb);
Neil Hormanead2ceb2009-03-11 09:49:55 +0000756 __kfree_skb(skb);
757}
758EXPORT_SYMBOL(consume_skb);
759
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100760void __kfree_skb_flush(void)
761{
762 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
763
764 /* flush skb_cache if containing objects */
765 if (nc->skb_count) {
766 kmem_cache_free_bulk(skbuff_head_cache, nc->skb_count,
767 nc->skb_cache);
768 nc->skb_count = 0;
769 }
770}
771
Jesper Dangaard Brouer15fad712016-02-08 13:15:04 +0100772static inline void _kfree_skb_defer(struct sk_buff *skb)
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100773{
774 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
775
776 /* drop skb->head and call any destructors for packet */
777 skb_release_all(skb);
778
779 /* record skb to CPU local list */
780 nc->skb_cache[nc->skb_count++] = skb;
781
782#ifdef CONFIG_SLUB
783 /* SLUB writes into objects when freeing */
784 prefetchw(skb);
785#endif
786
787 /* flush skb_cache if it is filled */
788 if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
789 kmem_cache_free_bulk(skbuff_head_cache, NAPI_SKB_CACHE_SIZE,
790 nc->skb_cache);
791 nc->skb_count = 0;
792 }
793}
Jesper Dangaard Brouer15fad712016-02-08 13:15:04 +0100794void __kfree_skb_defer(struct sk_buff *skb)
795{
796 _kfree_skb_defer(skb);
797}
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100798
799void napi_consume_skb(struct sk_buff *skb, int budget)
800{
801 if (unlikely(!skb))
802 return;
803
Jesper Dangaard Brouer885eb0a2016-03-11 09:43:58 +0100804 /* Zero budget indicate non-NAPI context called us, like netpoll */
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100805 if (unlikely(!budget)) {
Jesper Dangaard Brouer885eb0a2016-03-11 09:43:58 +0100806 dev_consume_skb_any(skb);
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100807 return;
808 }
809
810 if (likely(atomic_read(&skb->users) == 1))
811 smp_rmb();
812 else if (likely(!atomic_dec_and_test(&skb->users)))
813 return;
814 /* if reaching here SKB is ready to free */
815 trace_consume_skb(skb);
816
817 /* if SKB is a clone, don't handle this case */
Eric Dumazetabbdb5a2016-03-20 11:27:47 -0700818 if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100819 __kfree_skb(skb);
820 return;
821 }
822
Jesper Dangaard Brouer15fad712016-02-08 13:15:04 +0100823 _kfree_skb_defer(skb);
Jesper Dangaard Brouer795bb1c2016-02-08 13:14:59 +0100824}
825EXPORT_SYMBOL(napi_consume_skb);
826
Eric Dumazetb1937222014-09-28 22:18:47 -0700827/* Make sure a field is enclosed inside headers_start/headers_end section */
828#define CHECK_SKB_FIELD(field) \
829 BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
830 offsetof(struct sk_buff, headers_start)); \
831 BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
832 offsetof(struct sk_buff, headers_end)); \
833
Herbert Xudec18812007-10-14 00:37:30 -0700834static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
835{
836 new->tstamp = old->tstamp;
Eric Dumazetb1937222014-09-28 22:18:47 -0700837 /* We do not copy old->sk */
Herbert Xudec18812007-10-14 00:37:30 -0700838 new->dev = old->dev;
Eric Dumazetb1937222014-09-28 22:18:47 -0700839 memcpy(new->cb, old->cb, sizeof(old->cb));
Eric Dumazet7fee2262010-05-11 23:19:48 +0000840 skb_dst_copy(new, old);
Alexey Dobriyandef8b4f2008-10-28 13:24:06 -0700841#ifdef CONFIG_XFRM
Herbert Xudec18812007-10-14 00:37:30 -0700842 new->sp = secpath_get(old->sp);
843#endif
Eric Dumazetb1937222014-09-28 22:18:47 -0700844 __nf_copy(new, old, false);
Patrick McHardy6aa895b2008-07-14 22:49:06 -0700845
Eric Dumazetb1937222014-09-28 22:18:47 -0700846 /* Note : this field could be in headers_start/headers_end section
847 * It is not yet because we do not want to have a 16 bit hole
848 */
849 new->queue_mapping = old->queue_mapping;
Eliezer Tamir06021292013-06-10 11:39:50 +0300850
Eric Dumazetb1937222014-09-28 22:18:47 -0700851 memcpy(&new->headers_start, &old->headers_start,
852 offsetof(struct sk_buff, headers_end) -
853 offsetof(struct sk_buff, headers_start));
854 CHECK_SKB_FIELD(protocol);
855 CHECK_SKB_FIELD(csum);
856 CHECK_SKB_FIELD(hash);
857 CHECK_SKB_FIELD(priority);
858 CHECK_SKB_FIELD(skb_iif);
859 CHECK_SKB_FIELD(vlan_proto);
860 CHECK_SKB_FIELD(vlan_tci);
861 CHECK_SKB_FIELD(transport_header);
862 CHECK_SKB_FIELD(network_header);
863 CHECK_SKB_FIELD(mac_header);
864 CHECK_SKB_FIELD(inner_protocol);
865 CHECK_SKB_FIELD(inner_transport_header);
866 CHECK_SKB_FIELD(inner_network_header);
867 CHECK_SKB_FIELD(inner_mac_header);
868 CHECK_SKB_FIELD(mark);
869#ifdef CONFIG_NETWORK_SECMARK
870 CHECK_SKB_FIELD(secmark);
871#endif
Cong Wange0d10952013-08-01 11:10:25 +0800872#ifdef CONFIG_NET_RX_BUSY_POLL
Eric Dumazetb1937222014-09-28 22:18:47 -0700873 CHECK_SKB_FIELD(napi_id);
Eliezer Tamir06021292013-06-10 11:39:50 +0300874#endif
Eric Dumazet2bd82482015-02-03 23:48:24 -0800875#ifdef CONFIG_XPS
876 CHECK_SKB_FIELD(sender_cpu);
877#endif
Eric Dumazetb1937222014-09-28 22:18:47 -0700878#ifdef CONFIG_NET_SCHED
879 CHECK_SKB_FIELD(tc_index);
880#ifdef CONFIG_NET_CLS_ACT
881 CHECK_SKB_FIELD(tc_verd);
882#endif
883#endif
884
Herbert Xudec18812007-10-14 00:37:30 -0700885}
886
Herbert Xu82c49a32009-05-22 22:11:37 +0000887/*
888 * You should not add any new code to this function. Add it to
889 * __copy_skb_header above instead.
890 */
Herbert Xue0053ec2007-10-14 00:37:52 -0700891static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893#define C(x) n->x = skb->x
894
895 n->next = n->prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 n->sk = NULL;
Herbert Xudec18812007-10-14 00:37:30 -0700897 __copy_skb_header(n, skb);
898
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 C(len);
900 C(data_len);
Alexey Dobriyan3e6b3b22007-03-16 15:00:46 -0700901 C(mac_len);
Patrick McHardy334a8132007-06-25 04:35:20 -0700902 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
Paul Moore02f1c892008-01-07 21:56:41 -0800903 n->cloned = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 n->nohdr = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 n->destructor = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 C(tail);
907 C(end);
Paul Moore02f1c892008-01-07 21:56:41 -0800908 C(head);
Eric Dumazetd3836f22012-04-27 00:33:38 +0000909 C(head_frag);
Paul Moore02f1c892008-01-07 21:56:41 -0800910 C(data);
911 C(truesize);
912 atomic_set(&n->users, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913
914 atomic_inc(&(skb_shinfo(skb)->dataref));
915 skb->cloned = 1;
916
917 return n;
Herbert Xue0053ec2007-10-14 00:37:52 -0700918#undef C
919}
920
921/**
922 * skb_morph - morph one skb into another
923 * @dst: the skb to receive the contents
924 * @src: the skb to supply the contents
925 *
926 * This is identical to skb_clone except that the target skb is
927 * supplied by the user.
928 *
929 * The target skb is returned upon exit.
930 */
931struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
932{
Herbert Xu2d4baff2007-11-26 23:11:19 +0800933 skb_release_all(dst);
Herbert Xue0053ec2007-10-14 00:37:52 -0700934 return __skb_clone(dst, src);
935}
936EXPORT_SYMBOL_GPL(skb_morph);
937
Ben Hutchings2c530402012-07-10 10:55:09 +0000938/**
939 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
Michael S. Tsirkin48c83012011-08-31 08:03:29 +0000940 * @skb: the skb to modify
941 * @gfp_mask: allocation priority
942 *
943 * This must be called on SKBTX_DEV_ZEROCOPY skb.
944 * It will copy all frags into kernel and drop the reference
945 * to userspace pages.
946 *
947 * If this function is called from an interrupt gfp_mask() must be
948 * %GFP_ATOMIC.
949 *
950 * Returns 0 on success or a negative error code on failure
951 * to allocate kernel memory to copy to.
952 */
953int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
Shirley Maa6686f22011-07-06 12:22:12 +0000954{
955 int i;
956 int num_frags = skb_shinfo(skb)->nr_frags;
957 struct page *page, *head = NULL;
958 struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg;
959
960 for (i = 0; i < num_frags; i++) {
961 u8 *vaddr;
962 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
963
Krishna Kumar02756ed2012-07-17 02:05:29 +0000964 page = alloc_page(gfp_mask);
Shirley Maa6686f22011-07-06 12:22:12 +0000965 if (!page) {
966 while (head) {
Sunghan Suh40dadff2013-07-12 16:17:23 +0900967 struct page *next = (struct page *)page_private(head);
Shirley Maa6686f22011-07-06 12:22:12 +0000968 put_page(head);
969 head = next;
970 }
971 return -ENOMEM;
972 }
Eric Dumazet51c56b02012-04-05 11:35:15 +0200973 vaddr = kmap_atomic(skb_frag_page(f));
Shirley Maa6686f22011-07-06 12:22:12 +0000974 memcpy(page_address(page),
Eric Dumazet9e903e02011-10-18 21:00:24 +0000975 vaddr + f->page_offset, skb_frag_size(f));
Eric Dumazet51c56b02012-04-05 11:35:15 +0200976 kunmap_atomic(vaddr);
Sunghan Suh40dadff2013-07-12 16:17:23 +0900977 set_page_private(page, (unsigned long)head);
Shirley Maa6686f22011-07-06 12:22:12 +0000978 head = page;
979 }
980
981 /* skb frags release userspace buffers */
Krishna Kumar02756ed2012-07-17 02:05:29 +0000982 for (i = 0; i < num_frags; i++)
Ian Campbella8605c62011-10-19 23:01:49 +0000983 skb_frag_unref(skb, i);
Shirley Maa6686f22011-07-06 12:22:12 +0000984
Michael S. Tsirkine19d6762012-11-01 09:16:22 +0000985 uarg->callback(uarg, false);
Shirley Maa6686f22011-07-06 12:22:12 +0000986
987 /* skb frags point to kernel buffers */
Krishna Kumar02756ed2012-07-17 02:05:29 +0000988 for (i = num_frags - 1; i >= 0; i--) {
989 __skb_fill_page_desc(skb, i, head, 0,
990 skb_shinfo(skb)->frags[i].size);
Sunghan Suh40dadff2013-07-12 16:17:23 +0900991 head = (struct page *)page_private(head);
Shirley Maa6686f22011-07-06 12:22:12 +0000992 }
Michael S. Tsirkin48c83012011-08-31 08:03:29 +0000993
994 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
Shirley Maa6686f22011-07-06 12:22:12 +0000995 return 0;
996}
Michael S. Tsirkindcc0fb72012-07-20 09:23:20 +0000997EXPORT_SYMBOL_GPL(skb_copy_ubufs);
Shirley Maa6686f22011-07-06 12:22:12 +0000998
Herbert Xue0053ec2007-10-14 00:37:52 -0700999/**
1000 * skb_clone - duplicate an sk_buff
1001 * @skb: buffer to clone
1002 * @gfp_mask: allocation priority
1003 *
1004 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
1005 * copies share the same packet data but not structure. The new
1006 * buffer has a reference count of 1. If the allocation fails the
1007 * function returns %NULL otherwise the new buffer is returned.
1008 *
1009 * If this function is called from an interrupt gfp_mask() must be
1010 * %GFP_ATOMIC.
1011 */
1012
1013struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
1014{
Eric Dumazetd0bf4a92014-09-29 13:29:15 -07001015 struct sk_buff_fclones *fclones = container_of(skb,
1016 struct sk_buff_fclones,
1017 skb1);
Eric Dumazet6ffe75e2014-12-03 17:04:39 -08001018 struct sk_buff *n;
Herbert Xue0053ec2007-10-14 00:37:52 -07001019
Michael S. Tsirkin70008aa2012-07-20 09:23:10 +00001020 if (skb_orphan_frags(skb, gfp_mask))
1021 return NULL;
Shirley Maa6686f22011-07-06 12:22:12 +00001022
Herbert Xue0053ec2007-10-14 00:37:52 -07001023 if (skb->fclone == SKB_FCLONE_ORIG &&
Eric Dumazet6ffe75e2014-12-03 17:04:39 -08001024 atomic_read(&fclones->fclone_ref) == 1) {
1025 n = &fclones->skb2;
1026 atomic_set(&fclones->fclone_ref, 2);
Herbert Xue0053ec2007-10-14 00:37:52 -07001027 } else {
Mel Gormanc93bdd02012-07-31 16:44:19 -07001028 if (skb_pfmemalloc(skb))
1029 gfp_mask |= __GFP_MEMALLOC;
1030
Herbert Xue0053ec2007-10-14 00:37:52 -07001031 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
1032 if (!n)
1033 return NULL;
Vegard Nossumfe55f6d2008-08-30 12:16:35 +02001034
1035 kmemcheck_annotate_bitfield(n, flags1);
Herbert Xue0053ec2007-10-14 00:37:52 -07001036 n->fclone = SKB_FCLONE_UNAVAILABLE;
1037 }
1038
1039 return __skb_clone(n, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001041EXPORT_SYMBOL(skb_clone);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042
Pravin B Shelarf5b17292013-03-07 13:21:40 +00001043static void skb_headers_offset_update(struct sk_buff *skb, int off)
1044{
Eric Dumazet030737b2013-10-19 11:42:54 -07001045 /* Only adjust this if it actually is csum_start rather than csum */
1046 if (skb->ip_summed == CHECKSUM_PARTIAL)
1047 skb->csum_start += off;
Pravin B Shelarf5b17292013-03-07 13:21:40 +00001048 /* {transport,network,mac}_header and tail are relative to skb->head */
1049 skb->transport_header += off;
1050 skb->network_header += off;
1051 if (skb_mac_header_was_set(skb))
1052 skb->mac_header += off;
1053 skb->inner_transport_header += off;
1054 skb->inner_network_header += off;
Pravin B Shelaraefbd2b2013-03-07 13:21:46 +00001055 skb->inner_mac_header += off;
Pravin B Shelarf5b17292013-03-07 13:21:40 +00001056}
1057
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
1059{
Herbert Xudec18812007-10-14 00:37:30 -07001060 __copy_skb_header(new, old);
1061
Herbert Xu79671682006-06-22 02:40:14 -07001062 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
1063 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
1064 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065}
1066
Mel Gormanc93bdd02012-07-31 16:44:19 -07001067static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
1068{
1069 if (skb_pfmemalloc(skb))
1070 return SKB_ALLOC_RX;
1071 return 0;
1072}
1073
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074/**
1075 * skb_copy - create private copy of an sk_buff
1076 * @skb: buffer to copy
1077 * @gfp_mask: allocation priority
1078 *
1079 * Make a copy of both an &sk_buff and its data. This is used when the
1080 * caller wishes to modify the data and needs a private copy of the
1081 * data to alter. Returns %NULL on failure or the pointer to the buffer
1082 * on success. The returned buffer has a reference count of 1.
1083 *
1084 * As by-product this function converts non-linear &sk_buff to linear
1085 * one, so that &sk_buff becomes completely private and caller is allowed
1086 * to modify all the data of returned buffer. This means that this
1087 * function is not recommended for use in circumstances when only
1088 * header is going to be modified. Use pskb_copy() instead.
1089 */
1090
Al Virodd0fc662005-10-07 07:46:04 +01001091struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092{
Eric Dumazet6602ceb2010-09-01 05:25:10 +00001093 int headerlen = skb_headroom(skb);
Alexander Duyckec47ea82012-05-04 14:26:56 +00001094 unsigned int size = skb_end_offset(skb) + skb->data_len;
Mel Gormanc93bdd02012-07-31 16:44:19 -07001095 struct sk_buff *n = __alloc_skb(size, gfp_mask,
1096 skb_alloc_rx_flag(skb), NUMA_NO_NODE);
Eric Dumazet6602ceb2010-09-01 05:25:10 +00001097
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 if (!n)
1099 return NULL;
1100
1101 /* Set the data pointer */
1102 skb_reserve(n, headerlen);
1103 /* Set the tail pointer and length */
1104 skb_put(n, skb->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105
1106 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
1107 BUG();
1108
1109 copy_skb_header(n, skb);
1110 return n;
1111}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001112EXPORT_SYMBOL(skb_copy);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113
1114/**
Octavian Purdilabad93e92014-06-12 01:36:26 +03001115 * __pskb_copy_fclone - create copy of an sk_buff with private head.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 * @skb: buffer to copy
Eric Dumazet117632e2011-12-03 21:39:53 +00001117 * @headroom: headroom of new skb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 * @gfp_mask: allocation priority
Octavian Purdilabad93e92014-06-12 01:36:26 +03001119 * @fclone: if true allocate the copy of the skb from the fclone
1120 * cache instead of the head cache; it is recommended to set this
1121 * to true for the cases where the copy will likely be cloned
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 *
1123 * Make a copy of both an &sk_buff and part of its data, located
1124 * in header. Fragmented data remain shared. This is used when
1125 * the caller wishes to modify only header of &sk_buff and needs
1126 * private copy of the header to alter. Returns %NULL on failure
1127 * or the pointer to the buffer on success.
1128 * The returned buffer has a reference count of 1.
1129 */
1130
Octavian Purdilabad93e92014-06-12 01:36:26 +03001131struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1132 gfp_t gfp_mask, bool fclone)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133{
Eric Dumazet117632e2011-12-03 21:39:53 +00001134 unsigned int size = skb_headlen(skb) + headroom;
Octavian Purdilabad93e92014-06-12 01:36:26 +03001135 int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
1136 struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
Eric Dumazet6602ceb2010-09-01 05:25:10 +00001137
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138 if (!n)
1139 goto out;
1140
1141 /* Set the data pointer */
Eric Dumazet117632e2011-12-03 21:39:53 +00001142 skb_reserve(n, headroom);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 /* Set the tail pointer and length */
1144 skb_put(n, skb_headlen(skb));
1145 /* Copy the bytes */
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -03001146 skb_copy_from_linear_data(skb, n->data, n->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147
Herbert Xu25f484a2006-11-07 14:57:15 -08001148 n->truesize += skb->data_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 n->data_len = skb->data_len;
1150 n->len = skb->len;
1151
1152 if (skb_shinfo(skb)->nr_frags) {
1153 int i;
1154
Michael S. Tsirkin70008aa2012-07-20 09:23:10 +00001155 if (skb_orphan_frags(skb, gfp_mask)) {
1156 kfree_skb(n);
1157 n = NULL;
1158 goto out;
Shirley Maa6686f22011-07-06 12:22:12 +00001159 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1161 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
Ian Campbellea2ab692011-08-22 23:44:58 +00001162 skb_frag_ref(skb, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 }
1164 skb_shinfo(n)->nr_frags = i;
1165 }
1166
David S. Miller21dc3302010-08-23 00:13:46 -07001167 if (skb_has_frag_list(skb)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
1169 skb_clone_fraglist(n);
1170 }
1171
1172 copy_skb_header(n, skb);
1173out:
1174 return n;
1175}
Octavian Purdilabad93e92014-06-12 01:36:26 +03001176EXPORT_SYMBOL(__pskb_copy_fclone);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177
1178/**
1179 * pskb_expand_head - reallocate header of &sk_buff
1180 * @skb: buffer to reallocate
1181 * @nhead: room to add at head
1182 * @ntail: room to add at tail
1183 * @gfp_mask: allocation priority
1184 *
Mathias Krausebc323832013-11-07 14:18:26 +01001185 * Expands (or creates identical copy, if @nhead and @ntail are zero)
1186 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 * reference count of 1. Returns zero in the case of success or error,
1188 * if expansion failed. In the last case, &sk_buff is not changed.
1189 *
1190 * All the pointers pointing into skb header may change and must be
1191 * reloaded after call to this function.
1192 */
1193
Victor Fusco86a76ca2005-07-08 14:57:47 -07001194int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
Al Virodd0fc662005-10-07 07:46:04 +01001195 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196{
1197 int i;
1198 u8 *data;
Alexander Duyckec47ea82012-05-04 14:26:56 +00001199 int size = nhead + skb_end_offset(skb) + ntail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 long off;
1201
Herbert Xu4edd87a2008-10-01 07:09:38 -07001202 BUG_ON(nhead < 0);
1203
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 if (skb_shared(skb))
1205 BUG();
1206
1207 size = SKB_DATA_ALIGN(size);
1208
Mel Gormanc93bdd02012-07-31 16:44:19 -07001209 if (skb_pfmemalloc(skb))
1210 gfp_mask |= __GFP_MEMALLOC;
1211 data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
1212 gfp_mask, NUMA_NO_NODE, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 if (!data)
1214 goto nodata;
Eric Dumazet87151b82012-04-10 20:08:39 +00001215 size = SKB_WITH_OVERHEAD(ksize(data));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216
1217 /* Copy only real data... and, alas, header. This should be
Eric Dumazet6602ceb2010-09-01 05:25:10 +00001218 * optimized for the cases when header is void.
1219 */
1220 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
1221
1222 memcpy((struct skb_shared_info *)(data + size),
1223 skb_shinfo(skb),
Eric Dumazetfed66382010-07-22 19:09:08 +00001224 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
Alexander Duyck3e245912012-05-04 14:26:51 +00001226 /*
1227 * if shinfo is shared we must drop the old head gracefully, but if it
1228 * is not we can just drop the old head and let the existing refcount
1229 * be since all we did is relocate the values
1230 */
1231 if (skb_cloned(skb)) {
Shirley Maa6686f22011-07-06 12:22:12 +00001232 /* copy this zero copy skb frags */
Michael S. Tsirkin70008aa2012-07-20 09:23:10 +00001233 if (skb_orphan_frags(skb, gfp_mask))
1234 goto nofrags;
Eric Dumazet1fd63042010-09-02 23:09:32 +00001235 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
Ian Campbellea2ab692011-08-22 23:44:58 +00001236 skb_frag_ref(skb, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237
Eric Dumazet1fd63042010-09-02 23:09:32 +00001238 if (skb_has_frag_list(skb))
1239 skb_clone_fraglist(skb);
1240
1241 skb_release_data(skb);
Alexander Duyck3e245912012-05-04 14:26:51 +00001242 } else {
1243 skb_free_head(skb);
Eric Dumazet1fd63042010-09-02 23:09:32 +00001244 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 off = (data + nhead) - skb->head;
1246
1247 skb->head = data;
Eric Dumazetd3836f22012-04-27 00:33:38 +00001248 skb->head_frag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 skb->data += off;
Arnaldo Carvalho de Melo4305b542007-04-19 20:43:29 -07001250#ifdef NET_SKBUFF_DATA_USES_OFFSET
1251 skb->end = size;
Patrick McHardy56eb8882007-04-09 11:45:04 -07001252 off = nhead;
Arnaldo Carvalho de Melo4305b542007-04-19 20:43:29 -07001253#else
1254 skb->end = skb->head + size;
Patrick McHardy56eb8882007-04-09 11:45:04 -07001255#endif
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -07001256 skb->tail += off;
Peter Pan(潘卫平)b41abb42013-06-06 21:27:21 +08001257 skb_headers_offset_update(skb, nhead);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 skb->cloned = 0;
Patrick McHardy334a8132007-06-25 04:35:20 -07001259 skb->hdr_len = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 skb->nohdr = 0;
1261 atomic_set(&skb_shinfo(skb)->dataref, 1);
1262 return 0;
1263
Shirley Maa6686f22011-07-06 12:22:12 +00001264nofrags:
1265 kfree(data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266nodata:
1267 return -ENOMEM;
1268}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001269EXPORT_SYMBOL(pskb_expand_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270
1271/* Make private copy of skb with writable head and some headroom */
1272
1273struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
1274{
1275 struct sk_buff *skb2;
1276 int delta = headroom - skb_headroom(skb);
1277
1278 if (delta <= 0)
1279 skb2 = pskb_copy(skb, GFP_ATOMIC);
1280 else {
1281 skb2 = skb_clone(skb, GFP_ATOMIC);
1282 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
1283 GFP_ATOMIC)) {
1284 kfree_skb(skb2);
1285 skb2 = NULL;
1286 }
1287 }
1288 return skb2;
1289}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001290EXPORT_SYMBOL(skb_realloc_headroom);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291
1292/**
1293 * skb_copy_expand - copy and expand sk_buff
1294 * @skb: buffer to copy
1295 * @newheadroom: new free bytes at head
1296 * @newtailroom: new free bytes at tail
1297 * @gfp_mask: allocation priority
1298 *
1299 * Make a copy of both an &sk_buff and its data and while doing so
1300 * allocate additional space.
1301 *
1302 * This is used when the caller wishes to modify the data and needs a
1303 * private copy of the data to alter as well as more space for new fields.
1304 * Returns %NULL on failure or the pointer to the buffer
1305 * on success. The returned buffer has a reference count of 1.
1306 *
1307 * You must pass %GFP_ATOMIC as the allocation priority if this function
1308 * is called from an interrupt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 */
1310struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
Victor Fusco86a76ca2005-07-08 14:57:47 -07001311 int newheadroom, int newtailroom,
Al Virodd0fc662005-10-07 07:46:04 +01001312 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313{
1314 /*
1315 * Allocate the copy buffer
1316 */
Mel Gormanc93bdd02012-07-31 16:44:19 -07001317 struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
1318 gfp_mask, skb_alloc_rx_flag(skb),
1319 NUMA_NO_NODE);
Patrick McHardyefd1e8d2007-04-10 18:30:09 -07001320 int oldheadroom = skb_headroom(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 int head_copy_len, head_copy_off;
1322
1323 if (!n)
1324 return NULL;
1325
1326 skb_reserve(n, newheadroom);
1327
1328 /* Set the tail pointer and length */
1329 skb_put(n, skb->len);
1330
Patrick McHardyefd1e8d2007-04-10 18:30:09 -07001331 head_copy_len = oldheadroom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 head_copy_off = 0;
1333 if (newheadroom <= head_copy_len)
1334 head_copy_len = newheadroom;
1335 else
1336 head_copy_off = newheadroom - head_copy_len;
1337
1338 /* Copy the linear header and data. */
1339 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
1340 skb->len + head_copy_len))
1341 BUG();
1342
1343 copy_skb_header(n, skb);
1344
Eric Dumazet030737b2013-10-19 11:42:54 -07001345 skb_headers_offset_update(n, newheadroom - oldheadroom);
Patrick McHardyefd1e8d2007-04-10 18:30:09 -07001346
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 return n;
1348}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001349EXPORT_SYMBOL(skb_copy_expand);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350
1351/**
1352 * skb_pad - zero pad the tail of an skb
1353 * @skb: buffer to pad
1354 * @pad: space to pad
1355 *
1356 * Ensure that a buffer is followed by a padding area that is zero
1357 * filled. Used by network drivers which may DMA or transfer data
1358 * beyond the buffer end onto the wire.
1359 *
Herbert Xu5b057c62006-06-23 02:06:41 -07001360 * May return error in out of memory cases. The skb is freed on error.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 */
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +09001362
Herbert Xu5b057c62006-06-23 02:06:41 -07001363int skb_pad(struct sk_buff *skb, int pad)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364{
Herbert Xu5b057c62006-06-23 02:06:41 -07001365 int err;
1366 int ntail;
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +09001367
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 /* If the skbuff is non linear tailroom is always zero.. */
Herbert Xu5b057c62006-06-23 02:06:41 -07001369 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370 memset(skb->data+skb->len, 0, pad);
Herbert Xu5b057c62006-06-23 02:06:41 -07001371 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 }
Herbert Xu5b057c62006-06-23 02:06:41 -07001373
Arnaldo Carvalho de Melo4305b542007-04-19 20:43:29 -07001374 ntail = skb->data_len + pad - (skb->end - skb->tail);
Herbert Xu5b057c62006-06-23 02:06:41 -07001375 if (likely(skb_cloned(skb) || ntail > 0)) {
1376 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
1377 if (unlikely(err))
1378 goto free_skb;
1379 }
1380
1381 /* FIXME: The use of this function with non-linear skb's really needs
1382 * to be audited.
1383 */
1384 err = skb_linearize(skb);
1385 if (unlikely(err))
1386 goto free_skb;
1387
1388 memset(skb->data + skb->len, 0, pad);
1389 return 0;
1390
1391free_skb:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 kfree_skb(skb);
Herbert Xu5b057c62006-06-23 02:06:41 -07001393 return err;
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +09001394}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001395EXPORT_SYMBOL(skb_pad);
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +09001396
Ilpo Järvinen0dde3e12008-03-27 17:43:41 -07001397/**
Mathias Krause0c7ddf32013-11-07 14:18:24 +01001398 * pskb_put - add data to the tail of a potentially fragmented buffer
1399 * @skb: start of the buffer to use
1400 * @tail: tail fragment of the buffer to use
1401 * @len: amount of data to add
1402 *
1403 * This function extends the used data area of the potentially
1404 * fragmented buffer. @tail must be the last fragment of @skb -- or
1405 * @skb itself. If this would exceed the total buffer size the kernel
1406 * will panic. A pointer to the first byte of the extra data is
1407 * returned.
1408 */
1409
1410unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
1411{
1412 if (tail != skb) {
1413 skb->data_len += len;
1414 skb->len += len;
1415 }
1416 return skb_put(tail, len);
1417}
1418EXPORT_SYMBOL_GPL(pskb_put);
1419
1420/**
Ilpo Järvinen0dde3e12008-03-27 17:43:41 -07001421 * skb_put - add data to a buffer
1422 * @skb: buffer to use
1423 * @len: amount of data to add
1424 *
1425 * This function extends the used data area of the buffer. If this would
1426 * exceed the total buffer size the kernel will panic. A pointer to the
1427 * first byte of the extra data is returned.
1428 */
1429unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
1430{
1431 unsigned char *tmp = skb_tail_pointer(skb);
1432 SKB_LINEAR_ASSERT(skb);
1433 skb->tail += len;
1434 skb->len += len;
1435 if (unlikely(skb->tail > skb->end))
1436 skb_over_panic(skb, len, __builtin_return_address(0));
1437 return tmp;
1438}
1439EXPORT_SYMBOL(skb_put);
1440
Ilpo Järvinen6be8ac22008-03-27 17:47:24 -07001441/**
Ilpo Järvinenc2aa2702008-03-27 17:52:40 -07001442 * skb_push - add data to the start of a buffer
1443 * @skb: buffer to use
1444 * @len: amount of data to add
1445 *
1446 * This function extends the used data area of the buffer at the buffer
1447 * start. If this would exceed the total buffer headroom the kernel will
1448 * panic. A pointer to the first byte of the extra data is returned.
1449 */
1450unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
1451{
1452 skb->data -= len;
1453 skb->len += len;
1454 if (unlikely(skb->data<skb->head))
1455 skb_under_panic(skb, len, __builtin_return_address(0));
1456 return skb->data;
1457}
1458EXPORT_SYMBOL(skb_push);
1459
1460/**
Ilpo Järvinen6be8ac22008-03-27 17:47:24 -07001461 * skb_pull - remove data from the start of a buffer
1462 * @skb: buffer to use
1463 * @len: amount of data to remove
1464 *
1465 * This function removes data from the start of a buffer, returning
1466 * the memory to the headroom. A pointer to the next data in the buffer
1467 * is returned. Once the data has been pulled future pushes will overwrite
1468 * the old data.
1469 */
1470unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
1471{
David S. Miller47d29642010-05-02 02:21:44 -07001472 return skb_pull_inline(skb, len);
Ilpo Järvinen6be8ac22008-03-27 17:47:24 -07001473}
1474EXPORT_SYMBOL(skb_pull);
1475
Ilpo Järvinen419ae742008-03-27 17:54:01 -07001476/**
1477 * skb_trim - remove end from a buffer
1478 * @skb: buffer to alter
1479 * @len: new length
1480 *
1481 * Cut the length of a buffer down by removing data from the tail. If
1482 * the buffer is already under the length specified it is not modified.
1483 * The skb must be linear.
1484 */
1485void skb_trim(struct sk_buff *skb, unsigned int len)
1486{
1487 if (skb->len > len)
1488 __skb_trim(skb, len);
1489}
1490EXPORT_SYMBOL(skb_trim);
1491
Herbert Xu3cc0e872006-06-09 16:13:38 -07001492/* Trims skb to length len. It can change skb pointers.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 */
1494
Herbert Xu3cc0e872006-06-09 16:13:38 -07001495int ___pskb_trim(struct sk_buff *skb, unsigned int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496{
Herbert Xu27b437c2006-07-13 19:26:39 -07001497 struct sk_buff **fragp;
1498 struct sk_buff *frag;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499 int offset = skb_headlen(skb);
1500 int nfrags = skb_shinfo(skb)->nr_frags;
1501 int i;
Herbert Xu27b437c2006-07-13 19:26:39 -07001502 int err;
1503
1504 if (skb_cloned(skb) &&
1505 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
1506 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507
Herbert Xuf4d26fb2006-07-30 20:20:28 -07001508 i = 0;
1509 if (offset >= len)
1510 goto drop_pages;
1511
1512 for (; i < nfrags; i++) {
Eric Dumazet9e903e02011-10-18 21:00:24 +00001513 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
Herbert Xu27b437c2006-07-13 19:26:39 -07001514
1515 if (end < len) {
1516 offset = end;
1517 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 }
Herbert Xu27b437c2006-07-13 19:26:39 -07001519
Eric Dumazet9e903e02011-10-18 21:00:24 +00001520 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
Herbert Xu27b437c2006-07-13 19:26:39 -07001521
Herbert Xuf4d26fb2006-07-30 20:20:28 -07001522drop_pages:
Herbert Xu27b437c2006-07-13 19:26:39 -07001523 skb_shinfo(skb)->nr_frags = i;
1524
1525 for (; i < nfrags; i++)
Ian Campbellea2ab692011-08-22 23:44:58 +00001526 skb_frag_unref(skb, i);
Herbert Xu27b437c2006-07-13 19:26:39 -07001527
David S. Miller21dc3302010-08-23 00:13:46 -07001528 if (skb_has_frag_list(skb))
Herbert Xu27b437c2006-07-13 19:26:39 -07001529 skb_drop_fraglist(skb);
Herbert Xuf4d26fb2006-07-30 20:20:28 -07001530 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531 }
1532
Herbert Xu27b437c2006-07-13 19:26:39 -07001533 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
1534 fragp = &frag->next) {
1535 int end = offset + frag->len;
1536
1537 if (skb_shared(frag)) {
1538 struct sk_buff *nfrag;
1539
1540 nfrag = skb_clone(frag, GFP_ATOMIC);
1541 if (unlikely(!nfrag))
1542 return -ENOMEM;
1543
1544 nfrag->next = frag->next;
Eric Dumazet85bb2a62012-04-19 02:24:53 +00001545 consume_skb(frag);
Herbert Xu27b437c2006-07-13 19:26:39 -07001546 frag = nfrag;
1547 *fragp = frag;
1548 }
1549
1550 if (end < len) {
1551 offset = end;
1552 continue;
1553 }
1554
1555 if (end > len &&
1556 unlikely((err = pskb_trim(frag, len - offset))))
1557 return err;
1558
1559 if (frag->next)
1560 skb_drop_list(&frag->next);
1561 break;
1562 }
1563
Herbert Xuf4d26fb2006-07-30 20:20:28 -07001564done:
Herbert Xu27b437c2006-07-13 19:26:39 -07001565 if (len > skb_headlen(skb)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 skb->data_len -= skb->len - len;
1567 skb->len = len;
1568 } else {
Herbert Xu27b437c2006-07-13 19:26:39 -07001569 skb->len = len;
1570 skb->data_len = 0;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -07001571 skb_set_tail_pointer(skb, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572 }
1573
1574 return 0;
1575}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001576EXPORT_SYMBOL(___pskb_trim);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577
1578/**
1579 * __pskb_pull_tail - advance tail of skb header
1580 * @skb: buffer to reallocate
1581 * @delta: number of bytes to advance tail
1582 *
1583 * The function makes a sense only on a fragmented &sk_buff,
1584 * it expands header moving its tail forward and copying necessary
1585 * data from fragmented part.
1586 *
1587 * &sk_buff MUST have reference count of 1.
1588 *
1589 * Returns %NULL (and &sk_buff does not change) if pull failed
1590 * or value of new tail of skb in the case of success.
1591 *
1592 * All the pointers pointing into skb header may change and must be
1593 * reloaded after call to this function.
1594 */
1595
1596/* Moves tail of skb head forward, copying data from fragmented part,
1597 * when it is necessary.
1598 * 1. It may fail due to malloc failure.
1599 * 2. It may change skb pointers.
1600 *
1601 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1602 */
1603unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
1604{
1605 /* If skb has not enough free space at tail, get new one
1606 * plus 128 bytes for future expansions. If we have enough
1607 * room at tail, reallocate without expansion only if skb is cloned.
1608 */
Arnaldo Carvalho de Melo4305b542007-04-19 20:43:29 -07001609 int i, k, eat = (skb->tail + delta) - skb->end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610
1611 if (eat > 0 || skb_cloned(skb)) {
1612 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
1613 GFP_ATOMIC))
1614 return NULL;
1615 }
1616
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -07001617 if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001618 BUG();
1619
1620 /* Optimization: no fragments, no reasons to preestimate
1621 * size of pulled pages. Superb.
1622 */
David S. Miller21dc3302010-08-23 00:13:46 -07001623 if (!skb_has_frag_list(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624 goto pull_pages;
1625
1626 /* Estimate size of pulled pages. */
1627 eat = delta;
1628 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
Eric Dumazet9e903e02011-10-18 21:00:24 +00001629 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1630
1631 if (size >= eat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001632 goto pull_pages;
Eric Dumazet9e903e02011-10-18 21:00:24 +00001633 eat -= size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634 }
1635
1636 /* If we need update frag list, we are in troubles.
1637 * Certainly, it possible to add an offset to skb data,
1638 * but taking into account that pulling is expected to
1639 * be very rare operation, it is worth to fight against
1640 * further bloating skb head and crucify ourselves here instead.
1641 * Pure masohism, indeed. 8)8)
1642 */
1643 if (eat) {
1644 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1645 struct sk_buff *clone = NULL;
1646 struct sk_buff *insp = NULL;
1647
1648 do {
Kris Katterjohn09a62662006-01-08 22:24:28 -08001649 BUG_ON(!list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001650
1651 if (list->len <= eat) {
1652 /* Eaten as whole. */
1653 eat -= list->len;
1654 list = list->next;
1655 insp = list;
1656 } else {
1657 /* Eaten partially. */
1658
1659 if (skb_shared(list)) {
1660 /* Sucks! We need to fork list. :-( */
1661 clone = skb_clone(list, GFP_ATOMIC);
1662 if (!clone)
1663 return NULL;
1664 insp = list->next;
1665 list = clone;
1666 } else {
1667 /* This may be pulled without
1668 * problems. */
1669 insp = list;
1670 }
1671 if (!pskb_pull(list, eat)) {
Wei Yongjunf3fbbe02009-02-25 00:37:32 +00001672 kfree_skb(clone);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673 return NULL;
1674 }
1675 break;
1676 }
1677 } while (eat);
1678
1679 /* Free pulled out fragments. */
1680 while ((list = skb_shinfo(skb)->frag_list) != insp) {
1681 skb_shinfo(skb)->frag_list = list->next;
1682 kfree_skb(list);
1683 }
1684 /* And insert new clone at head. */
1685 if (clone) {
1686 clone->next = list;
1687 skb_shinfo(skb)->frag_list = clone;
1688 }
1689 }
1690 /* Success! Now we may commit changes to skb data. */
1691
1692pull_pages:
1693 eat = delta;
1694 k = 0;
1695 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
Eric Dumazet9e903e02011-10-18 21:00:24 +00001696 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1697
1698 if (size <= eat) {
Ian Campbellea2ab692011-08-22 23:44:58 +00001699 skb_frag_unref(skb, i);
Eric Dumazet9e903e02011-10-18 21:00:24 +00001700 eat -= size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 } else {
1702 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
1703 if (eat) {
1704 skb_shinfo(skb)->frags[k].page_offset += eat;
Eric Dumazet9e903e02011-10-18 21:00:24 +00001705 skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 eat = 0;
1707 }
1708 k++;
1709 }
1710 }
1711 skb_shinfo(skb)->nr_frags = k;
1712
1713 skb->tail += delta;
1714 skb->data_len -= delta;
1715
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -07001716 return skb_tail_pointer(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001718EXPORT_SYMBOL(__pskb_pull_tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719
Eric Dumazet22019b12011-07-29 18:37:31 +00001720/**
1721 * skb_copy_bits - copy bits from skb to kernel buffer
1722 * @skb: source skb
1723 * @offset: offset in source
1724 * @to: destination buffer
1725 * @len: number of bytes to copy
1726 *
1727 * Copy the specified number of bytes from the source skb to the
1728 * destination buffer.
1729 *
1730 * CAUTION ! :
1731 * If its prototype is ever changed,
1732 * check arch/{*}/net/{*}.S files,
1733 * since it is called from BPF assembly code.
1734 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1736{
David S. Miller1a028e52007-04-27 15:21:23 -07001737 int start = skb_headlen(skb);
David S. Millerfbb398a2009-06-09 00:18:59 -07001738 struct sk_buff *frag_iter;
1739 int i, copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740
1741 if (offset > (int)skb->len - len)
1742 goto fault;
1743
1744 /* Copy header. */
David S. Miller1a028e52007-04-27 15:21:23 -07001745 if ((copy = start - offset) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 if (copy > len)
1747 copy = len;
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -03001748 skb_copy_from_linear_data_offset(skb, offset, to, copy);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 if ((len -= copy) == 0)
1750 return 0;
1751 offset += copy;
1752 to += copy;
1753 }
1754
1755 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
David S. Miller1a028e52007-04-27 15:21:23 -07001756 int end;
Eric Dumazet51c56b02012-04-05 11:35:15 +02001757 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758
Ilpo Järvinen547b7922008-07-25 21:43:18 -07001759 WARN_ON(start > offset + len);
David S. Miller1a028e52007-04-27 15:21:23 -07001760
Eric Dumazet51c56b02012-04-05 11:35:15 +02001761 end = start + skb_frag_size(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762 if ((copy = end - offset) > 0) {
1763 u8 *vaddr;
1764
1765 if (copy > len)
1766 copy = len;
1767
Eric Dumazet51c56b02012-04-05 11:35:15 +02001768 vaddr = kmap_atomic(skb_frag_page(f));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 memcpy(to,
Eric Dumazet51c56b02012-04-05 11:35:15 +02001770 vaddr + f->page_offset + offset - start,
1771 copy);
1772 kunmap_atomic(vaddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773
1774 if ((len -= copy) == 0)
1775 return 0;
1776 offset += copy;
1777 to += copy;
1778 }
David S. Miller1a028e52007-04-27 15:21:23 -07001779 start = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001780 }
1781
David S. Millerfbb398a2009-06-09 00:18:59 -07001782 skb_walk_frags(skb, frag_iter) {
1783 int end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784
David S. Millerfbb398a2009-06-09 00:18:59 -07001785 WARN_ON(start > offset + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786
David S. Millerfbb398a2009-06-09 00:18:59 -07001787 end = start + frag_iter->len;
1788 if ((copy = end - offset) > 0) {
1789 if (copy > len)
1790 copy = len;
1791 if (skb_copy_bits(frag_iter, offset - start, to, copy))
1792 goto fault;
1793 if ((len -= copy) == 0)
1794 return 0;
1795 offset += copy;
1796 to += copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 }
David S. Millerfbb398a2009-06-09 00:18:59 -07001798 start = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 }
Shirley Maa6686f22011-07-06 12:22:12 +00001800
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801 if (!len)
1802 return 0;
1803
1804fault:
1805 return -EFAULT;
1806}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08001807EXPORT_SYMBOL(skb_copy_bits);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808
Jens Axboe9c55e012007-11-06 23:30:13 -08001809/*
1810 * Callback from splice_to_pipe(), if we need to release some pages
1811 * at the end of the spd in case we error'ed out in filling the pipe.
1812 */
1813static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
1814{
Jarek Poplawski8b9d3722009-01-19 17:03:56 -08001815 put_page(spd->pages[i]);
1816}
Jens Axboe9c55e012007-11-06 23:30:13 -08001817
David S. Millera108d5f2012-04-23 23:06:11 -04001818static struct page *linear_to_page(struct page *page, unsigned int *len,
1819 unsigned int *offset,
Eric Dumazet18aafc62013-01-11 14:46:37 +00001820 struct sock *sk)
Jarek Poplawski8b9d3722009-01-19 17:03:56 -08001821{
Eric Dumazet5640f762012-09-23 23:04:42 +00001822 struct page_frag *pfrag = sk_page_frag(sk);
Jarek Poplawski8b9d3722009-01-19 17:03:56 -08001823
Eric Dumazet5640f762012-09-23 23:04:42 +00001824 if (!sk_page_frag_refill(sk, pfrag))
1825 return NULL;
Jarek Poplawski4fb66992009-02-01 00:41:42 -08001826
Eric Dumazet5640f762012-09-23 23:04:42 +00001827 *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
Jarek Poplawski4fb66992009-02-01 00:41:42 -08001828
Eric Dumazet5640f762012-09-23 23:04:42 +00001829 memcpy(page_address(pfrag->page) + pfrag->offset,
1830 page_address(page) + *offset, *len);
1831 *offset = pfrag->offset;
1832 pfrag->offset += *len;
Jarek Poplawski4fb66992009-02-01 00:41:42 -08001833
Eric Dumazet5640f762012-09-23 23:04:42 +00001834 return pfrag->page;
Jens Axboe9c55e012007-11-06 23:30:13 -08001835}
1836
Eric Dumazet41c73a02012-04-22 12:26:16 +00001837static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
1838 struct page *page,
1839 unsigned int offset)
1840{
1841 return spd->nr_pages &&
1842 spd->pages[spd->nr_pages - 1] == page &&
1843 (spd->partial[spd->nr_pages - 1].offset +
1844 spd->partial[spd->nr_pages - 1].len == offset);
1845}
1846
Jens Axboe9c55e012007-11-06 23:30:13 -08001847/*
1848 * Fill page/offset/length into spd, if it can hold more pages.
1849 */
David S. Millera108d5f2012-04-23 23:06:11 -04001850static bool spd_fill_page(struct splice_pipe_desc *spd,
1851 struct pipe_inode_info *pipe, struct page *page,
1852 unsigned int *len, unsigned int offset,
Eric Dumazet18aafc62013-01-11 14:46:37 +00001853 bool linear,
David S. Millera108d5f2012-04-23 23:06:11 -04001854 struct sock *sk)
Jens Axboe9c55e012007-11-06 23:30:13 -08001855{
Eric Dumazet41c73a02012-04-22 12:26:16 +00001856 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
David S. Millera108d5f2012-04-23 23:06:11 -04001857 return true;
Jens Axboe9c55e012007-11-06 23:30:13 -08001858
Jarek Poplawski8b9d3722009-01-19 17:03:56 -08001859 if (linear) {
Eric Dumazet18aafc62013-01-11 14:46:37 +00001860 page = linear_to_page(page, len, &offset, sk);
Jarek Poplawski8b9d3722009-01-19 17:03:56 -08001861 if (!page)
David S. Millera108d5f2012-04-23 23:06:11 -04001862 return true;
Eric Dumazet41c73a02012-04-22 12:26:16 +00001863 }
1864 if (spd_can_coalesce(spd, page, offset)) {
1865 spd->partial[spd->nr_pages - 1].len += *len;
David S. Millera108d5f2012-04-23 23:06:11 -04001866 return false;
Eric Dumazet41c73a02012-04-22 12:26:16 +00001867 }
1868 get_page(page);
Jens Axboe9c55e012007-11-06 23:30:13 -08001869 spd->pages[spd->nr_pages] = page;
Jarek Poplawski4fb66992009-02-01 00:41:42 -08001870 spd->partial[spd->nr_pages].len = *len;
Jens Axboe9c55e012007-11-06 23:30:13 -08001871 spd->partial[spd->nr_pages].offset = offset;
Jens Axboe9c55e012007-11-06 23:30:13 -08001872 spd->nr_pages++;
Jarek Poplawski8b9d3722009-01-19 17:03:56 -08001873
David S. Millera108d5f2012-04-23 23:06:11 -04001874 return false;
Jens Axboe9c55e012007-11-06 23:30:13 -08001875}
1876
David S. Millera108d5f2012-04-23 23:06:11 -04001877static bool __splice_segment(struct page *page, unsigned int poff,
1878 unsigned int plen, unsigned int *off,
Eric Dumazet18aafc62013-01-11 14:46:37 +00001879 unsigned int *len,
Eric Dumazetd7ccf7c2012-04-23 23:35:04 -04001880 struct splice_pipe_desc *spd, bool linear,
David S. Millera108d5f2012-04-23 23:06:11 -04001881 struct sock *sk,
1882 struct pipe_inode_info *pipe)
Octavian Purdila2870c432008-07-15 00:49:11 -07001883{
1884 if (!*len)
David S. Millera108d5f2012-04-23 23:06:11 -04001885 return true;
Octavian Purdila2870c432008-07-15 00:49:11 -07001886
1887 /* skip this segment if already processed */
1888 if (*off >= plen) {
1889 *off -= plen;
David S. Millera108d5f2012-04-23 23:06:11 -04001890 return false;
Octavian Purdiladb43a282008-06-27 17:27:21 -07001891 }
Jens Axboe9c55e012007-11-06 23:30:13 -08001892
Octavian Purdila2870c432008-07-15 00:49:11 -07001893 /* ignore any bits we already processed */
Eric Dumazet9ca1b222013-01-05 21:31:18 +00001894 poff += *off;
1895 plen -= *off;
1896 *off = 0;
Octavian Purdila2870c432008-07-15 00:49:11 -07001897
Eric Dumazet18aafc62013-01-11 14:46:37 +00001898 do {
1899 unsigned int flen = min(*len, plen);
Octavian Purdila2870c432008-07-15 00:49:11 -07001900
Eric Dumazet18aafc62013-01-11 14:46:37 +00001901 if (spd_fill_page(spd, pipe, page, &flen, poff,
1902 linear, sk))
1903 return true;
1904 poff += flen;
1905 plen -= flen;
1906 *len -= flen;
1907 } while (*len && plen);
Octavian Purdila2870c432008-07-15 00:49:11 -07001908
David S. Millera108d5f2012-04-23 23:06:11 -04001909 return false;
Octavian Purdila2870c432008-07-15 00:49:11 -07001910}
1911
1912/*
David S. Millera108d5f2012-04-23 23:06:11 -04001913 * Map linear and fragment data from the skb to spd. It reports true if the
Octavian Purdila2870c432008-07-15 00:49:11 -07001914 * pipe is full or if we already spliced the requested length.
1915 */
David S. Millera108d5f2012-04-23 23:06:11 -04001916static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
1917 unsigned int *offset, unsigned int *len,
1918 struct splice_pipe_desc *spd, struct sock *sk)
Octavian Purdila2870c432008-07-15 00:49:11 -07001919{
1920 int seg;
Tom Herbertfa9835e2016-03-07 14:11:04 -08001921 struct sk_buff *iter;
Octavian Purdila2870c432008-07-15 00:49:11 -07001922
Eric Dumazet1d0c0b32012-04-27 02:10:03 +00001923 /* map the linear part :
Alexander Duyck2996d312012-05-02 18:18:42 +00001924 * If skb->head_frag is set, this 'linear' part is backed by a
1925 * fragment, and if the head is not shared with any clones then
1926 * we can avoid a copy since we own the head portion of this page.
Jens Axboe9c55e012007-11-06 23:30:13 -08001927 */
Octavian Purdila2870c432008-07-15 00:49:11 -07001928 if (__splice_segment(virt_to_page(skb->data),
1929 (unsigned long) skb->data & (PAGE_SIZE - 1),
1930 skb_headlen(skb),
Eric Dumazet18aafc62013-01-11 14:46:37 +00001931 offset, len, spd,
Alexander Duyck3a7c1ee42012-05-03 01:09:42 +00001932 skb_head_is_locked(skb),
Eric Dumazet1d0c0b32012-04-27 02:10:03 +00001933 sk, pipe))
David S. Millera108d5f2012-04-23 23:06:11 -04001934 return true;
Jens Axboe9c55e012007-11-06 23:30:13 -08001935
1936 /*
1937 * then map the fragments
1938 */
Jens Axboe9c55e012007-11-06 23:30:13 -08001939 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
1940 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
1941
Ian Campbellea2ab692011-08-22 23:44:58 +00001942 if (__splice_segment(skb_frag_page(f),
Eric Dumazet9e903e02011-10-18 21:00:24 +00001943 f->page_offset, skb_frag_size(f),
Eric Dumazet18aafc62013-01-11 14:46:37 +00001944 offset, len, spd, false, sk, pipe))
David S. Millera108d5f2012-04-23 23:06:11 -04001945 return true;
Jens Axboe9c55e012007-11-06 23:30:13 -08001946 }
1947
Tom Herbertfa9835e2016-03-07 14:11:04 -08001948 skb_walk_frags(skb, iter) {
1949 if (*offset >= iter->len) {
1950 *offset -= iter->len;
1951 continue;
1952 }
1953 /* __skb_splice_bits() only fails if the output has no room
1954 * left, so no point in going over the frag_list for the error
1955 * case.
1956 */
1957 if (__skb_splice_bits(iter, pipe, offset, len, spd, sk))
1958 return true;
1959 }
1960
David S. Millera108d5f2012-04-23 23:06:11 -04001961 return false;
Jens Axboe9c55e012007-11-06 23:30:13 -08001962}
1963
Hannes Frederic Sowaa60e3cc2015-05-21 17:00:00 +02001964ssize_t skb_socket_splice(struct sock *sk,
1965 struct pipe_inode_info *pipe,
1966 struct splice_pipe_desc *spd)
1967{
1968 int ret;
1969
1970 /* Drop the socket lock, otherwise we have reverse
1971 * locking dependencies between sk_lock and i_mutex
1972 * here as compared to sendfile(). We enter here
1973 * with the socket lock held, and splice_to_pipe() will
1974 * grab the pipe inode lock. For sendfile() emulation,
1975 * we call into ->sendpage() with the i_mutex lock held
1976 * and networking will grab the socket lock.
1977 */
1978 release_sock(sk);
1979 ret = splice_to_pipe(pipe, spd);
1980 lock_sock(sk);
1981
1982 return ret;
1983}
1984
Jens Axboe9c55e012007-11-06 23:30:13 -08001985/*
1986 * Map data from the skb to a pipe. Should handle both the linear part,
Tom Herbertfa9835e2016-03-07 14:11:04 -08001987 * the fragments, and the frag list.
Jens Axboe9c55e012007-11-06 23:30:13 -08001988 */
Hannes Frederic Sowaa60e3cc2015-05-21 17:00:00 +02001989int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
Jens Axboe9c55e012007-11-06 23:30:13 -08001990 struct pipe_inode_info *pipe, unsigned int tlen,
Hannes Frederic Sowaa60e3cc2015-05-21 17:00:00 +02001991 unsigned int flags,
1992 ssize_t (*splice_cb)(struct sock *,
1993 struct pipe_inode_info *,
1994 struct splice_pipe_desc *))
Jens Axboe9c55e012007-11-06 23:30:13 -08001995{
Eric Dumazet41c73a02012-04-22 12:26:16 +00001996 struct partial_page partial[MAX_SKB_FRAGS];
1997 struct page *pages[MAX_SKB_FRAGS];
Jens Axboe9c55e012007-11-06 23:30:13 -08001998 struct splice_pipe_desc spd = {
1999 .pages = pages,
2000 .partial = partial,
Eric Dumazet047fe362012-06-12 15:24:40 +02002001 .nr_pages_max = MAX_SKB_FRAGS,
Jens Axboe9c55e012007-11-06 23:30:13 -08002002 .flags = flags,
Miklos Szeredi28a625c2014-01-22 19:36:57 +01002003 .ops = &nosteal_pipe_buf_ops,
Jens Axboe9c55e012007-11-06 23:30:13 -08002004 .spd_release = sock_spd_release,
2005 };
Jens Axboe35f3d142010-05-20 10:43:18 +02002006 int ret = 0;
2007
Tom Herbertfa9835e2016-03-07 14:11:04 -08002008 __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
Jens Axboe9c55e012007-11-06 23:30:13 -08002009
Hannes Frederic Sowaa60e3cc2015-05-21 17:00:00 +02002010 if (spd.nr_pages)
2011 ret = splice_cb(sk, pipe, &spd);
Jens Axboe9c55e012007-11-06 23:30:13 -08002012
Jens Axboe35f3d142010-05-20 10:43:18 +02002013 return ret;
Jens Axboe9c55e012007-11-06 23:30:13 -08002014}
Hannes Frederic Sowa2b514572015-05-21 17:00:01 +02002015EXPORT_SYMBOL_GPL(skb_splice_bits);
Jens Axboe9c55e012007-11-06 23:30:13 -08002016
Herbert Xu357b40a2005-04-19 22:30:14 -07002017/**
2018 * skb_store_bits - store bits from kernel buffer to skb
2019 * @skb: destination buffer
2020 * @offset: offset in destination
2021 * @from: source buffer
2022 * @len: number of bytes to copy
2023 *
2024 * Copy the specified number of bytes from the source buffer to the
2025 * destination skb. This function handles all the messy bits of
2026 * traversing fragment lists and such.
2027 */
2028
Stephen Hemminger0c6fcc82007-04-20 16:40:01 -07002029int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
Herbert Xu357b40a2005-04-19 22:30:14 -07002030{
David S. Miller1a028e52007-04-27 15:21:23 -07002031 int start = skb_headlen(skb);
David S. Millerfbb398a2009-06-09 00:18:59 -07002032 struct sk_buff *frag_iter;
2033 int i, copy;
Herbert Xu357b40a2005-04-19 22:30:14 -07002034
2035 if (offset > (int)skb->len - len)
2036 goto fault;
2037
David S. Miller1a028e52007-04-27 15:21:23 -07002038 if ((copy = start - offset) > 0) {
Herbert Xu357b40a2005-04-19 22:30:14 -07002039 if (copy > len)
2040 copy = len;
Arnaldo Carvalho de Melo27d7ff42007-03-31 11:55:19 -03002041 skb_copy_to_linear_data_offset(skb, offset, from, copy);
Herbert Xu357b40a2005-04-19 22:30:14 -07002042 if ((len -= copy) == 0)
2043 return 0;
2044 offset += copy;
2045 from += copy;
2046 }
2047
2048 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2049 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
David S. Miller1a028e52007-04-27 15:21:23 -07002050 int end;
Herbert Xu357b40a2005-04-19 22:30:14 -07002051
Ilpo Järvinen547b7922008-07-25 21:43:18 -07002052 WARN_ON(start > offset + len);
David S. Miller1a028e52007-04-27 15:21:23 -07002053
Eric Dumazet9e903e02011-10-18 21:00:24 +00002054 end = start + skb_frag_size(frag);
Herbert Xu357b40a2005-04-19 22:30:14 -07002055 if ((copy = end - offset) > 0) {
2056 u8 *vaddr;
2057
2058 if (copy > len)
2059 copy = len;
2060
Eric Dumazet51c56b02012-04-05 11:35:15 +02002061 vaddr = kmap_atomic(skb_frag_page(frag));
David S. Miller1a028e52007-04-27 15:21:23 -07002062 memcpy(vaddr + frag->page_offset + offset - start,
2063 from, copy);
Eric Dumazet51c56b02012-04-05 11:35:15 +02002064 kunmap_atomic(vaddr);
Herbert Xu357b40a2005-04-19 22:30:14 -07002065
2066 if ((len -= copy) == 0)
2067 return 0;
2068 offset += copy;
2069 from += copy;
2070 }
David S. Miller1a028e52007-04-27 15:21:23 -07002071 start = end;
Herbert Xu357b40a2005-04-19 22:30:14 -07002072 }
2073
David S. Millerfbb398a2009-06-09 00:18:59 -07002074 skb_walk_frags(skb, frag_iter) {
2075 int end;
Herbert Xu357b40a2005-04-19 22:30:14 -07002076
David S. Millerfbb398a2009-06-09 00:18:59 -07002077 WARN_ON(start > offset + len);
Herbert Xu357b40a2005-04-19 22:30:14 -07002078
David S. Millerfbb398a2009-06-09 00:18:59 -07002079 end = start + frag_iter->len;
2080 if ((copy = end - offset) > 0) {
2081 if (copy > len)
2082 copy = len;
2083 if (skb_store_bits(frag_iter, offset - start,
2084 from, copy))
2085 goto fault;
2086 if ((len -= copy) == 0)
2087 return 0;
2088 offset += copy;
2089 from += copy;
Herbert Xu357b40a2005-04-19 22:30:14 -07002090 }
David S. Millerfbb398a2009-06-09 00:18:59 -07002091 start = end;
Herbert Xu357b40a2005-04-19 22:30:14 -07002092 }
2093 if (!len)
2094 return 0;
2095
2096fault:
2097 return -EFAULT;
2098}
Herbert Xu357b40a2005-04-19 22:30:14 -07002099EXPORT_SYMBOL(skb_store_bits);
2100
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101/* Checksum skb data. */
Daniel Borkmann2817a332013-10-30 11:50:51 +01002102__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2103 __wsum csum, const struct skb_checksum_ops *ops)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104{
David S. Miller1a028e52007-04-27 15:21:23 -07002105 int start = skb_headlen(skb);
2106 int i, copy = start - offset;
David S. Millerfbb398a2009-06-09 00:18:59 -07002107 struct sk_buff *frag_iter;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002108 int pos = 0;
2109
2110 /* Checksum header. */
2111 if (copy > 0) {
2112 if (copy > len)
2113 copy = len;
Daniel Borkmann2817a332013-10-30 11:50:51 +01002114 csum = ops->update(skb->data + offset, copy, csum);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002115 if ((len -= copy) == 0)
2116 return csum;
2117 offset += copy;
2118 pos = copy;
2119 }
2120
2121 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
David S. Miller1a028e52007-04-27 15:21:23 -07002122 int end;
Eric Dumazet51c56b02012-04-05 11:35:15 +02002123 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124
Ilpo Järvinen547b7922008-07-25 21:43:18 -07002125 WARN_ON(start > offset + len);
David S. Miller1a028e52007-04-27 15:21:23 -07002126
Eric Dumazet51c56b02012-04-05 11:35:15 +02002127 end = start + skb_frag_size(frag);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128 if ((copy = end - offset) > 0) {
Al Viro44bb9362006-11-14 21:36:14 -08002129 __wsum csum2;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130 u8 *vaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002131
2132 if (copy > len)
2133 copy = len;
Eric Dumazet51c56b02012-04-05 11:35:15 +02002134 vaddr = kmap_atomic(skb_frag_page(frag));
Daniel Borkmann2817a332013-10-30 11:50:51 +01002135 csum2 = ops->update(vaddr + frag->page_offset +
2136 offset - start, copy, 0);
Eric Dumazet51c56b02012-04-05 11:35:15 +02002137 kunmap_atomic(vaddr);
Daniel Borkmann2817a332013-10-30 11:50:51 +01002138 csum = ops->combine(csum, csum2, pos, copy);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139 if (!(len -= copy))
2140 return csum;
2141 offset += copy;
2142 pos += copy;
2143 }
David S. Miller1a028e52007-04-27 15:21:23 -07002144 start = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145 }
2146
David S. Millerfbb398a2009-06-09 00:18:59 -07002147 skb_walk_frags(skb, frag_iter) {
2148 int end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002149
David S. Millerfbb398a2009-06-09 00:18:59 -07002150 WARN_ON(start > offset + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151
David S. Millerfbb398a2009-06-09 00:18:59 -07002152 end = start + frag_iter->len;
2153 if ((copy = end - offset) > 0) {
2154 __wsum csum2;
2155 if (copy > len)
2156 copy = len;
Daniel Borkmann2817a332013-10-30 11:50:51 +01002157 csum2 = __skb_checksum(frag_iter, offset - start,
2158 copy, 0, ops);
2159 csum = ops->combine(csum, csum2, pos, copy);
David S. Millerfbb398a2009-06-09 00:18:59 -07002160 if ((len -= copy) == 0)
2161 return csum;
2162 offset += copy;
2163 pos += copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164 }
David S. Millerfbb398a2009-06-09 00:18:59 -07002165 start = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002166 }
Kris Katterjohn09a62662006-01-08 22:24:28 -08002167 BUG_ON(len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168
2169 return csum;
2170}
Daniel Borkmann2817a332013-10-30 11:50:51 +01002171EXPORT_SYMBOL(__skb_checksum);
2172
2173__wsum skb_checksum(const struct sk_buff *skb, int offset,
2174 int len, __wsum csum)
2175{
2176 const struct skb_checksum_ops ops = {
Daniel Borkmanncea80ea82013-11-04 17:10:25 +01002177 .update = csum_partial_ext,
Daniel Borkmann2817a332013-10-30 11:50:51 +01002178 .combine = csum_block_add_ext,
2179 };
2180
2181 return __skb_checksum(skb, offset, len, csum, &ops);
2182}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002183EXPORT_SYMBOL(skb_checksum);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184
2185/* Both of above in one bottle. */
2186
Al Viro81d77662006-11-14 21:37:33 -08002187__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
2188 u8 *to, int len, __wsum csum)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002189{
David S. Miller1a028e52007-04-27 15:21:23 -07002190 int start = skb_headlen(skb);
2191 int i, copy = start - offset;
David S. Millerfbb398a2009-06-09 00:18:59 -07002192 struct sk_buff *frag_iter;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002193 int pos = 0;
2194
2195 /* Copy header. */
2196 if (copy > 0) {
2197 if (copy > len)
2198 copy = len;
2199 csum = csum_partial_copy_nocheck(skb->data + offset, to,
2200 copy, csum);
2201 if ((len -= copy) == 0)
2202 return csum;
2203 offset += copy;
2204 to += copy;
2205 pos = copy;
2206 }
2207
2208 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
David S. Miller1a028e52007-04-27 15:21:23 -07002209 int end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210
Ilpo Järvinen547b7922008-07-25 21:43:18 -07002211 WARN_ON(start > offset + len);
David S. Miller1a028e52007-04-27 15:21:23 -07002212
Eric Dumazet9e903e02011-10-18 21:00:24 +00002213 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002214 if ((copy = end - offset) > 0) {
Al Viro50842052006-11-14 21:36:34 -08002215 __wsum csum2;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216 u8 *vaddr;
2217 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2218
2219 if (copy > len)
2220 copy = len;
Eric Dumazet51c56b02012-04-05 11:35:15 +02002221 vaddr = kmap_atomic(skb_frag_page(frag));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002222 csum2 = csum_partial_copy_nocheck(vaddr +
David S. Miller1a028e52007-04-27 15:21:23 -07002223 frag->page_offset +
2224 offset - start, to,
2225 copy, 0);
Eric Dumazet51c56b02012-04-05 11:35:15 +02002226 kunmap_atomic(vaddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002227 csum = csum_block_add(csum, csum2, pos);
2228 if (!(len -= copy))
2229 return csum;
2230 offset += copy;
2231 to += copy;
2232 pos += copy;
2233 }
David S. Miller1a028e52007-04-27 15:21:23 -07002234 start = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002235 }
2236
David S. Millerfbb398a2009-06-09 00:18:59 -07002237 skb_walk_frags(skb, frag_iter) {
2238 __wsum csum2;
2239 int end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240
David S. Millerfbb398a2009-06-09 00:18:59 -07002241 WARN_ON(start > offset + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002242
David S. Millerfbb398a2009-06-09 00:18:59 -07002243 end = start + frag_iter->len;
2244 if ((copy = end - offset) > 0) {
2245 if (copy > len)
2246 copy = len;
2247 csum2 = skb_copy_and_csum_bits(frag_iter,
2248 offset - start,
2249 to, copy, 0);
2250 csum = csum_block_add(csum, csum2, pos);
2251 if ((len -= copy) == 0)
2252 return csum;
2253 offset += copy;
2254 to += copy;
2255 pos += copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002256 }
David S. Millerfbb398a2009-06-09 00:18:59 -07002257 start = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002258 }
Kris Katterjohn09a62662006-01-08 22:24:28 -08002259 BUG_ON(len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002260 return csum;
2261}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002262EXPORT_SYMBOL(skb_copy_and_csum_bits);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002263
Thomas Grafaf2806f2013-12-13 15:22:17 +01002264 /**
2265 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
2266 * @from: source buffer
2267 *
2268 * Calculates the amount of linear headroom needed in the 'to' skb passed
2269 * into skb_zerocopy().
2270 */
2271unsigned int
2272skb_zerocopy_headlen(const struct sk_buff *from)
2273{
2274 unsigned int hlen = 0;
2275
2276 if (!from->head_frag ||
2277 skb_headlen(from) < L1_CACHE_BYTES ||
2278 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
2279 hlen = skb_headlen(from);
2280
2281 if (skb_has_frag_list(from))
2282 hlen = from->len;
2283
2284 return hlen;
2285}
2286EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
2287
2288/**
2289 * skb_zerocopy - Zero copy skb to skb
2290 * @to: destination buffer
Masanari Iida7fceb4d2014-01-29 01:05:28 +09002291 * @from: source buffer
Thomas Grafaf2806f2013-12-13 15:22:17 +01002292 * @len: number of bytes to copy from source buffer
2293 * @hlen: size of linear headroom in destination buffer
2294 *
2295 * Copies up to `len` bytes from `from` to `to` by creating references
2296 * to the frags in the source buffer.
2297 *
2298 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
2299 * headroom in the `to` buffer.
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002300 *
2301 * Return value:
2302 * 0: everything is OK
2303 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
2304 * -EFAULT: skb_copy_bits() found some problem with skb geometry
Thomas Grafaf2806f2013-12-13 15:22:17 +01002305 */
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002306int
2307skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
Thomas Grafaf2806f2013-12-13 15:22:17 +01002308{
2309 int i, j = 0;
2310 int plen = 0; /* length of skb->head fragment */
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002311 int ret;
Thomas Grafaf2806f2013-12-13 15:22:17 +01002312 struct page *page;
2313 unsigned int offset;
2314
2315 BUG_ON(!from->head_frag && !hlen);
2316
2317 /* dont bother with small payloads */
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002318 if (len <= skb_tailroom(to))
2319 return skb_copy_bits(from, 0, skb_put(to, len), len);
Thomas Grafaf2806f2013-12-13 15:22:17 +01002320
2321 if (hlen) {
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002322 ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
2323 if (unlikely(ret))
2324 return ret;
Thomas Grafaf2806f2013-12-13 15:22:17 +01002325 len -= hlen;
2326 } else {
2327 plen = min_t(int, skb_headlen(from), len);
2328 if (plen) {
2329 page = virt_to_head_page(from->head);
2330 offset = from->data - (unsigned char *)page_address(page);
2331 __skb_fill_page_desc(to, 0, page, offset, plen);
2332 get_page(page);
2333 j = 1;
2334 len -= plen;
2335 }
2336 }
2337
2338 to->truesize += len + plen;
2339 to->len += len + plen;
2340 to->data_len += len + plen;
2341
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002342 if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
2343 skb_tx_error(from);
2344 return -ENOMEM;
2345 }
2346
Thomas Grafaf2806f2013-12-13 15:22:17 +01002347 for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
2348 if (!len)
2349 break;
2350 skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
2351 skb_shinfo(to)->frags[j].size = min_t(int, skb_shinfo(to)->frags[j].size, len);
2352 len -= skb_shinfo(to)->frags[j].size;
2353 skb_frag_ref(to, j);
2354 j++;
2355 }
2356 skb_shinfo(to)->nr_frags = j;
Zoltan Kiss36d5fe62014-03-26 22:37:45 +00002357
2358 return 0;
Thomas Grafaf2806f2013-12-13 15:22:17 +01002359}
2360EXPORT_SYMBOL_GPL(skb_zerocopy);
2361
Linus Torvalds1da177e2005-04-16 15:20:36 -07002362void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
2363{
Al Virod3bc23e2006-11-14 21:24:49 -08002364 __wsum csum;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 long csstart;
2366
Patrick McHardy84fa7932006-08-29 16:44:56 -07002367 if (skb->ip_summed == CHECKSUM_PARTIAL)
Michał Mirosław55508d62010-12-14 15:24:08 +00002368 csstart = skb_checksum_start_offset(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 else
2370 csstart = skb_headlen(skb);
2371
Kris Katterjohn09a62662006-01-08 22:24:28 -08002372 BUG_ON(csstart > skb_headlen(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -03002374 skb_copy_from_linear_data(skb, to, csstart);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002375
2376 csum = 0;
2377 if (csstart != skb->len)
2378 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
2379 skb->len - csstart, 0);
2380
Patrick McHardy84fa7932006-08-29 16:44:56 -07002381 if (skb->ip_summed == CHECKSUM_PARTIAL) {
Al Viroff1dcad2006-11-20 18:07:29 -08002382 long csstuff = csstart + skb->csum_offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383
Al Virod3bc23e2006-11-14 21:24:49 -08002384 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002385 }
2386}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002387EXPORT_SYMBOL(skb_copy_and_csum_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388
2389/**
2390 * skb_dequeue - remove from the head of the queue
2391 * @list: list to dequeue from
2392 *
2393 * Remove the head of the list. The list lock is taken so the function
2394 * may be used safely with other locking list functions. The head item is
2395 * returned or %NULL if the list is empty.
2396 */
2397
2398struct sk_buff *skb_dequeue(struct sk_buff_head *list)
2399{
2400 unsigned long flags;
2401 struct sk_buff *result;
2402
2403 spin_lock_irqsave(&list->lock, flags);
2404 result = __skb_dequeue(list);
2405 spin_unlock_irqrestore(&list->lock, flags);
2406 return result;
2407}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002408EXPORT_SYMBOL(skb_dequeue);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409
2410/**
2411 * skb_dequeue_tail - remove from the tail of the queue
2412 * @list: list to dequeue from
2413 *
2414 * Remove the tail of the list. The list lock is taken so the function
2415 * may be used safely with other locking list functions. The tail item is
2416 * returned or %NULL if the list is empty.
2417 */
2418struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
2419{
2420 unsigned long flags;
2421 struct sk_buff *result;
2422
2423 spin_lock_irqsave(&list->lock, flags);
2424 result = __skb_dequeue_tail(list);
2425 spin_unlock_irqrestore(&list->lock, flags);
2426 return result;
2427}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002428EXPORT_SYMBOL(skb_dequeue_tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002429
2430/**
2431 * skb_queue_purge - empty a list
2432 * @list: list to empty
2433 *
2434 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2435 * the list and one reference dropped. This function takes the list
2436 * lock and is atomic with respect to other list locking functions.
2437 */
2438void skb_queue_purge(struct sk_buff_head *list)
2439{
2440 struct sk_buff *skb;
2441 while ((skb = skb_dequeue(list)) != NULL)
2442 kfree_skb(skb);
2443}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002444EXPORT_SYMBOL(skb_queue_purge);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002445
2446/**
2447 * skb_queue_head - queue a buffer at the list head
2448 * @list: list to use
2449 * @newsk: buffer to queue
2450 *
2451 * Queue a buffer at the start of the list. This function takes the
2452 * list lock and can be used safely with other locking &sk_buff functions
2453 * safely.
2454 *
2455 * A buffer cannot be placed on two lists at the same time.
2456 */
2457void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
2458{
2459 unsigned long flags;
2460
2461 spin_lock_irqsave(&list->lock, flags);
2462 __skb_queue_head(list, newsk);
2463 spin_unlock_irqrestore(&list->lock, flags);
2464}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002465EXPORT_SYMBOL(skb_queue_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002466
2467/**
2468 * skb_queue_tail - queue a buffer at the list tail
2469 * @list: list to use
2470 * @newsk: buffer to queue
2471 *
2472 * Queue a buffer at the tail of the list. This function takes the
2473 * list lock and can be used safely with other locking &sk_buff functions
2474 * safely.
2475 *
2476 * A buffer cannot be placed on two lists at the same time.
2477 */
2478void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
2479{
2480 unsigned long flags;
2481
2482 spin_lock_irqsave(&list->lock, flags);
2483 __skb_queue_tail(list, newsk);
2484 spin_unlock_irqrestore(&list->lock, flags);
2485}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002486EXPORT_SYMBOL(skb_queue_tail);
David S. Miller8728b832005-08-09 19:25:21 -07002487
Linus Torvalds1da177e2005-04-16 15:20:36 -07002488/**
2489 * skb_unlink - remove a buffer from a list
2490 * @skb: buffer to remove
David S. Miller8728b832005-08-09 19:25:21 -07002491 * @list: list to use
Linus Torvalds1da177e2005-04-16 15:20:36 -07002492 *
David S. Miller8728b832005-08-09 19:25:21 -07002493 * Remove a packet from a list. The list locks are taken and this
2494 * function is atomic with respect to other list locked calls
Linus Torvalds1da177e2005-04-16 15:20:36 -07002495 *
David S. Miller8728b832005-08-09 19:25:21 -07002496 * You must know what list the SKB is on.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002497 */
David S. Miller8728b832005-08-09 19:25:21 -07002498void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002499{
David S. Miller8728b832005-08-09 19:25:21 -07002500 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002501
David S. Miller8728b832005-08-09 19:25:21 -07002502 spin_lock_irqsave(&list->lock, flags);
2503 __skb_unlink(skb, list);
2504 spin_unlock_irqrestore(&list->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002505}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002506EXPORT_SYMBOL(skb_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002507
Linus Torvalds1da177e2005-04-16 15:20:36 -07002508/**
2509 * skb_append - append a buffer
2510 * @old: buffer to insert after
2511 * @newsk: buffer to insert
David S. Miller8728b832005-08-09 19:25:21 -07002512 * @list: list to use
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513 *
2514 * Place a packet after a given packet in a list. The list locks are taken
2515 * and this function is atomic with respect to other list locked calls.
2516 * A buffer cannot be placed on two lists at the same time.
2517 */
David S. Miller8728b832005-08-09 19:25:21 -07002518void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002519{
2520 unsigned long flags;
2521
David S. Miller8728b832005-08-09 19:25:21 -07002522 spin_lock_irqsave(&list->lock, flags);
Gerrit Renker7de6c032008-04-14 00:05:09 -07002523 __skb_queue_after(list, old, newsk);
David S. Miller8728b832005-08-09 19:25:21 -07002524 spin_unlock_irqrestore(&list->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002525}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002526EXPORT_SYMBOL(skb_append);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002527
2528/**
2529 * skb_insert - insert a buffer
2530 * @old: buffer to insert before
2531 * @newsk: buffer to insert
David S. Miller8728b832005-08-09 19:25:21 -07002532 * @list: list to use
Linus Torvalds1da177e2005-04-16 15:20:36 -07002533 *
David S. Miller8728b832005-08-09 19:25:21 -07002534 * Place a packet before a given packet in a list. The list locks are
2535 * taken and this function is atomic with respect to other list locked
2536 * calls.
2537 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07002538 * A buffer cannot be placed on two lists at the same time.
2539 */
David S. Miller8728b832005-08-09 19:25:21 -07002540void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002541{
2542 unsigned long flags;
2543
David S. Miller8728b832005-08-09 19:25:21 -07002544 spin_lock_irqsave(&list->lock, flags);
2545 __skb_insert(newsk, old->prev, old, list);
2546 spin_unlock_irqrestore(&list->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002547}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002548EXPORT_SYMBOL(skb_insert);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002549
Linus Torvalds1da177e2005-04-16 15:20:36 -07002550static inline void skb_split_inside_header(struct sk_buff *skb,
2551 struct sk_buff* skb1,
2552 const u32 len, const int pos)
2553{
2554 int i;
2555
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -03002556 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
2557 pos - len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002558 /* And move data appendix as is. */
2559 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2560 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
2561
2562 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
2563 skb_shinfo(skb)->nr_frags = 0;
2564 skb1->data_len = skb->data_len;
2565 skb1->len += skb1->data_len;
2566 skb->data_len = 0;
2567 skb->len = len;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -07002568 skb_set_tail_pointer(skb, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002569}
2570
2571static inline void skb_split_no_header(struct sk_buff *skb,
2572 struct sk_buff* skb1,
2573 const u32 len, int pos)
2574{
2575 int i, k = 0;
2576 const int nfrags = skb_shinfo(skb)->nr_frags;
2577
2578 skb_shinfo(skb)->nr_frags = 0;
2579 skb1->len = skb1->data_len = skb->len - len;
2580 skb->len = len;
2581 skb->data_len = len - pos;
2582
2583 for (i = 0; i < nfrags; i++) {
Eric Dumazet9e903e02011-10-18 21:00:24 +00002584 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002585
2586 if (pos + size > len) {
2587 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
2588
2589 if (pos < len) {
2590 /* Split frag.
2591 * We have two variants in this case:
2592 * 1. Move all the frag to the second
2593 * part, if it is possible. F.e.
2594 * this approach is mandatory for TUX,
2595 * where splitting is expensive.
2596 * 2. Split is accurately. We make this.
2597 */
Ian Campbellea2ab692011-08-22 23:44:58 +00002598 skb_frag_ref(skb, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002599 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
Eric Dumazet9e903e02011-10-18 21:00:24 +00002600 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
2601 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002602 skb_shinfo(skb)->nr_frags++;
2603 }
2604 k++;
2605 } else
2606 skb_shinfo(skb)->nr_frags++;
2607 pos += size;
2608 }
2609 skb_shinfo(skb1)->nr_frags = k;
2610}
2611
2612/**
2613 * skb_split - Split fragmented skb to two parts at length len.
2614 * @skb: the buffer to split
2615 * @skb1: the buffer to receive the second part
2616 * @len: new length for skb
2617 */
2618void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
2619{
2620 int pos = skb_headlen(skb);
2621
Amerigo Wang68534c62013-02-19 22:51:30 +00002622 skb_shinfo(skb1)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002623 if (len < pos) /* Split line is inside header. */
2624 skb_split_inside_header(skb, skb1, len, pos);
2625 else /* Second chunk has no header, nothing to copy. */
2626 skb_split_no_header(skb, skb1, len, pos);
2627}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002628EXPORT_SYMBOL(skb_split);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002629
Ilpo Järvinen9f782db2008-11-25 13:57:01 -08002630/* Shifting from/to a cloned skb is a no-go.
2631 *
2632 * Caller cannot keep skb_shinfo related pointers past calling here!
2633 */
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002634static int skb_prepare_for_shift(struct sk_buff *skb)
2635{
Ilpo Järvinen0ace2852008-11-24 21:30:21 -08002636 return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002637}
2638
2639/**
2640 * skb_shift - Shifts paged data partially from skb to another
2641 * @tgt: buffer into which tail data gets added
2642 * @skb: buffer from which the paged data comes from
2643 * @shiftlen: shift up to this many bytes
2644 *
2645 * Attempts to shift up to shiftlen worth of bytes, which may be less than
Feng King20e994a2011-11-21 01:47:11 +00002646 * the length of the skb, from skb to tgt. Returns number bytes shifted.
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002647 * It's up to caller to free skb if everything was shifted.
2648 *
2649 * If @tgt runs out of frags, the whole operation is aborted.
2650 *
2651 * Skb cannot include anything else but paged data while tgt is allowed
2652 * to have non-paged data as well.
2653 *
2654 * TODO: full sized shift could be optimized but that would need
2655 * specialized skb free'er to handle frags without up-to-date nr_frags.
2656 */
2657int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
2658{
2659 int from, to, merge, todo;
2660 struct skb_frag_struct *fragfrom, *fragto;
2661
2662 BUG_ON(shiftlen > skb->len);
2663 BUG_ON(skb_headlen(skb)); /* Would corrupt stream */
2664
2665 todo = shiftlen;
2666 from = 0;
2667 to = skb_shinfo(tgt)->nr_frags;
2668 fragfrom = &skb_shinfo(skb)->frags[from];
2669
2670 /* Actual merge is delayed until the point when we know we can
2671 * commit all, so that we don't have to undo partial changes
2672 */
2673 if (!to ||
Ian Campbellea2ab692011-08-22 23:44:58 +00002674 !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
2675 fragfrom->page_offset)) {
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002676 merge = -1;
2677 } else {
2678 merge = to - 1;
2679
Eric Dumazet9e903e02011-10-18 21:00:24 +00002680 todo -= skb_frag_size(fragfrom);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002681 if (todo < 0) {
2682 if (skb_prepare_for_shift(skb) ||
2683 skb_prepare_for_shift(tgt))
2684 return 0;
2685
Ilpo Järvinen9f782db2008-11-25 13:57:01 -08002686 /* All previous frag pointers might be stale! */
2687 fragfrom = &skb_shinfo(skb)->frags[from];
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002688 fragto = &skb_shinfo(tgt)->frags[merge];
2689
Eric Dumazet9e903e02011-10-18 21:00:24 +00002690 skb_frag_size_add(fragto, shiftlen);
2691 skb_frag_size_sub(fragfrom, shiftlen);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002692 fragfrom->page_offset += shiftlen;
2693
2694 goto onlymerged;
2695 }
2696
2697 from++;
2698 }
2699
2700 /* Skip full, not-fitting skb to avoid expensive operations */
2701 if ((shiftlen == skb->len) &&
2702 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
2703 return 0;
2704
2705 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
2706 return 0;
2707
2708 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
2709 if (to == MAX_SKB_FRAGS)
2710 return 0;
2711
2712 fragfrom = &skb_shinfo(skb)->frags[from];
2713 fragto = &skb_shinfo(tgt)->frags[to];
2714
Eric Dumazet9e903e02011-10-18 21:00:24 +00002715 if (todo >= skb_frag_size(fragfrom)) {
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002716 *fragto = *fragfrom;
Eric Dumazet9e903e02011-10-18 21:00:24 +00002717 todo -= skb_frag_size(fragfrom);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002718 from++;
2719 to++;
2720
2721 } else {
Ian Campbellea2ab692011-08-22 23:44:58 +00002722 __skb_frag_ref(fragfrom);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002723 fragto->page = fragfrom->page;
2724 fragto->page_offset = fragfrom->page_offset;
Eric Dumazet9e903e02011-10-18 21:00:24 +00002725 skb_frag_size_set(fragto, todo);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002726
2727 fragfrom->page_offset += todo;
Eric Dumazet9e903e02011-10-18 21:00:24 +00002728 skb_frag_size_sub(fragfrom, todo);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002729 todo = 0;
2730
2731 to++;
2732 break;
2733 }
2734 }
2735
2736 /* Ready to "commit" this state change to tgt */
2737 skb_shinfo(tgt)->nr_frags = to;
2738
2739 if (merge >= 0) {
2740 fragfrom = &skb_shinfo(skb)->frags[0];
2741 fragto = &skb_shinfo(tgt)->frags[merge];
2742
Eric Dumazet9e903e02011-10-18 21:00:24 +00002743 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
Ian Campbellea2ab692011-08-22 23:44:58 +00002744 __skb_frag_unref(fragfrom);
Ilpo Järvinen832d11c2008-11-24 21:20:15 -08002745 }
2746
2747 /* Reposition in the original skb */
2748 to = 0;
2749 while (from < skb_shinfo(skb)->nr_frags)
2750 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
2751 skb_shinfo(skb)->nr_frags = to;
2752
2753 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
2754
2755onlymerged:
2756 /* Most likely the tgt won't ever need its checksum anymore, skb on
2757 * the other hand might need it if it needs to be resent
2758 */
2759 tgt->ip_summed = CHECKSUM_PARTIAL;
2760 skb->ip_summed = CHECKSUM_PARTIAL;
2761
2762 /* Yak, is it really working this way? Some helper please? */
2763 skb->len -= shiftlen;
2764 skb->data_len -= shiftlen;
2765 skb->truesize -= shiftlen;
2766 tgt->len += shiftlen;
2767 tgt->data_len += shiftlen;
2768 tgt->truesize += shiftlen;
2769
2770 return shiftlen;
2771}
2772
Thomas Graf677e90e2005-06-23 20:59:51 -07002773/**
2774 * skb_prepare_seq_read - Prepare a sequential read of skb data
2775 * @skb: the buffer to read
2776 * @from: lower offset of data to be read
2777 * @to: upper offset of data to be read
2778 * @st: state variable
2779 *
2780 * Initializes the specified state variable. Must be called before
2781 * invoking skb_seq_read() for the first time.
2782 */
2783void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
2784 unsigned int to, struct skb_seq_state *st)
2785{
2786 st->lower_offset = from;
2787 st->upper_offset = to;
2788 st->root_skb = st->cur_skb = skb;
2789 st->frag_idx = st->stepped_offset = 0;
2790 st->frag_data = NULL;
2791}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002792EXPORT_SYMBOL(skb_prepare_seq_read);
Thomas Graf677e90e2005-06-23 20:59:51 -07002793
2794/**
2795 * skb_seq_read - Sequentially read skb data
2796 * @consumed: number of bytes consumed by the caller so far
2797 * @data: destination pointer for data to be returned
2798 * @st: state variable
2799 *
Mathias Krausebc323832013-11-07 14:18:26 +01002800 * Reads a block of skb data at @consumed relative to the
Thomas Graf677e90e2005-06-23 20:59:51 -07002801 * lower offset specified to skb_prepare_seq_read(). Assigns
Mathias Krausebc323832013-11-07 14:18:26 +01002802 * the head of the data block to @data and returns the length
Thomas Graf677e90e2005-06-23 20:59:51 -07002803 * of the block or 0 if the end of the skb data or the upper
2804 * offset has been reached.
2805 *
2806 * The caller is not required to consume all of the data
Mathias Krausebc323832013-11-07 14:18:26 +01002807 * returned, i.e. @consumed is typically set to the number
Thomas Graf677e90e2005-06-23 20:59:51 -07002808 * of bytes already consumed and the next call to
2809 * skb_seq_read() will return the remaining part of the block.
2810 *
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002811 * Note 1: The size of each block of data returned can be arbitrary,
Masanari Iidae793c0f2014-09-04 23:44:36 +09002812 * this limitation is the cost for zerocopy sequential
Thomas Graf677e90e2005-06-23 20:59:51 -07002813 * reads of potentially non linear data.
2814 *
Randy Dunlapbc2cda12008-02-13 15:03:25 -08002815 * Note 2: Fragment lists within fragments are not implemented
Thomas Graf677e90e2005-06-23 20:59:51 -07002816 * at the moment, state->root_skb could be replaced with
2817 * a stack for this purpose.
2818 */
2819unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
2820 struct skb_seq_state *st)
2821{
2822 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
2823 skb_frag_t *frag;
2824
Wedson Almeida Filhoaeb193e2013-06-23 23:33:48 -07002825 if (unlikely(abs_offset >= st->upper_offset)) {
2826 if (st->frag_data) {
2827 kunmap_atomic(st->frag_data);
2828 st->frag_data = NULL;
2829 }
Thomas Graf677e90e2005-06-23 20:59:51 -07002830 return 0;
Wedson Almeida Filhoaeb193e2013-06-23 23:33:48 -07002831 }
Thomas Graf677e90e2005-06-23 20:59:51 -07002832
2833next_skb:
Herbert Xu95e3b242009-01-29 16:07:52 -08002834 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
Thomas Graf677e90e2005-06-23 20:59:51 -07002835
Thomas Chenault995b3372009-05-18 21:43:27 -07002836 if (abs_offset < block_limit && !st->frag_data) {
Herbert Xu95e3b242009-01-29 16:07:52 -08002837 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
Thomas Graf677e90e2005-06-23 20:59:51 -07002838 return block_limit - abs_offset;
2839 }
2840
2841 if (st->frag_idx == 0 && !st->frag_data)
2842 st->stepped_offset += skb_headlen(st->cur_skb);
2843
2844 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
2845 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
Eric Dumazet9e903e02011-10-18 21:00:24 +00002846 block_limit = skb_frag_size(frag) + st->stepped_offset;
Thomas Graf677e90e2005-06-23 20:59:51 -07002847
2848 if (abs_offset < block_limit) {
2849 if (!st->frag_data)
Eric Dumazet51c56b02012-04-05 11:35:15 +02002850 st->frag_data = kmap_atomic(skb_frag_page(frag));
Thomas Graf677e90e2005-06-23 20:59:51 -07002851
2852 *data = (u8 *) st->frag_data + frag->page_offset +
2853 (abs_offset - st->stepped_offset);
2854
2855 return block_limit - abs_offset;
2856 }
2857
2858 if (st->frag_data) {
Eric Dumazet51c56b02012-04-05 11:35:15 +02002859 kunmap_atomic(st->frag_data);
Thomas Graf677e90e2005-06-23 20:59:51 -07002860 st->frag_data = NULL;
2861 }
2862
2863 st->frag_idx++;
Eric Dumazet9e903e02011-10-18 21:00:24 +00002864 st->stepped_offset += skb_frag_size(frag);
Thomas Graf677e90e2005-06-23 20:59:51 -07002865 }
2866
Olaf Kirch5b5a60d2007-06-23 23:11:52 -07002867 if (st->frag_data) {
Eric Dumazet51c56b02012-04-05 11:35:15 +02002868 kunmap_atomic(st->frag_data);
Olaf Kirch5b5a60d2007-06-23 23:11:52 -07002869 st->frag_data = NULL;
2870 }
2871
David S. Miller21dc3302010-08-23 00:13:46 -07002872 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
Shyam Iyer71b33462009-01-29 16:12:42 -08002873 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
Thomas Graf677e90e2005-06-23 20:59:51 -07002874 st->frag_idx = 0;
2875 goto next_skb;
Shyam Iyer71b33462009-01-29 16:12:42 -08002876 } else if (st->cur_skb->next) {
2877 st->cur_skb = st->cur_skb->next;
Herbert Xu95e3b242009-01-29 16:07:52 -08002878 st->frag_idx = 0;
Thomas Graf677e90e2005-06-23 20:59:51 -07002879 goto next_skb;
2880 }
2881
2882 return 0;
2883}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002884EXPORT_SYMBOL(skb_seq_read);
Thomas Graf677e90e2005-06-23 20:59:51 -07002885
2886/**
2887 * skb_abort_seq_read - Abort a sequential read of skb data
2888 * @st: state variable
2889 *
2890 * Must be called if skb_seq_read() was not called until it
2891 * returned 0.
2892 */
2893void skb_abort_seq_read(struct skb_seq_state *st)
2894{
2895 if (st->frag_data)
Eric Dumazet51c56b02012-04-05 11:35:15 +02002896 kunmap_atomic(st->frag_data);
Thomas Graf677e90e2005-06-23 20:59:51 -07002897}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002898EXPORT_SYMBOL(skb_abort_seq_read);
Thomas Graf677e90e2005-06-23 20:59:51 -07002899
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002900#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2901
2902static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
2903 struct ts_config *conf,
2904 struct ts_state *state)
2905{
2906 return skb_seq_read(offset, text, TS_SKB_CB(state));
2907}
2908
2909static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
2910{
2911 skb_abort_seq_read(TS_SKB_CB(state));
2912}
2913
2914/**
2915 * skb_find_text - Find a text pattern in skb data
2916 * @skb: the buffer to look in
2917 * @from: search offset
2918 * @to: search limit
2919 * @config: textsearch configuration
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002920 *
2921 * Finds a pattern in the skb data according to the specified
2922 * textsearch configuration. Use textsearch_next() to retrieve
2923 * subsequent occurrences of the pattern. Returns the offset
2924 * to the first occurrence or UINT_MAX if no match was found.
2925 */
2926unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
Bojan Prtvar059a2442015-02-22 11:46:35 +01002927 unsigned int to, struct ts_config *config)
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002928{
Bojan Prtvar059a2442015-02-22 11:46:35 +01002929 struct ts_state state;
Phil Oesterf72b9482006-06-26 00:00:57 -07002930 unsigned int ret;
2931
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002932 config->get_next_block = skb_ts_get_next_block;
2933 config->finish = skb_ts_finish;
2934
Bojan Prtvar059a2442015-02-22 11:46:35 +01002935 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002936
Bojan Prtvar059a2442015-02-22 11:46:35 +01002937 ret = textsearch_find(config, &state);
Phil Oesterf72b9482006-06-26 00:00:57 -07002938 return (ret <= to - from ? ret : UINT_MAX);
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002939}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002940EXPORT_SYMBOL(skb_find_text);
Thomas Graf3fc7e8a2005-06-23 21:00:17 -07002941
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002942/**
Ben Hutchings2c530402012-07-10 10:55:09 +00002943 * skb_append_datato_frags - append the user data to a skb
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002944 * @sk: sock structure
Masanari Iidae793c0f2014-09-04 23:44:36 +09002945 * @skb: skb structure to be appended with user data.
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002946 * @getfrag: call back function to be used for getting the user data
2947 * @from: pointer to user message iov
2948 * @length: length of the iov message
2949 *
2950 * Description: This procedure append the user data in the fragment part
2951 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2952 */
2953int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
Martin Waitzdab96302005-12-05 13:40:12 -08002954 int (*getfrag)(void *from, char *to, int offset,
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002955 int len, int odd, struct sk_buff *skb),
2956 void *from, int length)
2957{
Eric Dumazetb2111722012-12-28 06:06:37 +00002958 int frg_cnt = skb_shinfo(skb)->nr_frags;
2959 int copy;
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002960 int offset = 0;
2961 int ret;
Eric Dumazetb2111722012-12-28 06:06:37 +00002962 struct page_frag *pfrag = &current->task_frag;
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002963
2964 do {
2965 /* Return error if we don't have space for new frag */
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002966 if (frg_cnt >= MAX_SKB_FRAGS)
Eric Dumazetb2111722012-12-28 06:06:37 +00002967 return -EMSGSIZE;
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002968
Eric Dumazetb2111722012-12-28 06:06:37 +00002969 if (!sk_page_frag_refill(sk, pfrag))
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002970 return -ENOMEM;
2971
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002972 /* copy the user data to page */
Eric Dumazetb2111722012-12-28 06:06:37 +00002973 copy = min_t(int, length, pfrag->size - pfrag->offset);
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002974
Eric Dumazetb2111722012-12-28 06:06:37 +00002975 ret = getfrag(from, page_address(pfrag->page) + pfrag->offset,
2976 offset, copy, 0, skb);
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002977 if (ret < 0)
2978 return -EFAULT;
2979
2980 /* copy was successful so update the size parameters */
Eric Dumazetb2111722012-12-28 06:06:37 +00002981 skb_fill_page_desc(skb, frg_cnt, pfrag->page, pfrag->offset,
2982 copy);
2983 frg_cnt++;
2984 pfrag->offset += copy;
2985 get_page(pfrag->page);
2986
2987 skb->truesize += copy;
2988 atomic_add(copy, &sk->sk_wmem_alloc);
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002989 skb->len += copy;
2990 skb->data_len += copy;
2991 offset += copy;
2992 length -= copy;
2993
2994 } while (length > 0);
2995
2996 return 0;
2997}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08002998EXPORT_SYMBOL(skb_append_datato_frags);
Ananda Rajue89e9cf2005-10-18 15:46:41 -07002999
Hannes Frederic Sowabe12a1f2015-05-21 16:59:58 +02003000int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
3001 int offset, size_t size)
3002{
3003 int i = skb_shinfo(skb)->nr_frags;
3004
3005 if (skb_can_coalesce(skb, i, page, offset)) {
3006 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
3007 } else if (i < MAX_SKB_FRAGS) {
3008 get_page(page);
3009 skb_fill_page_desc(skb, i, page, offset, size);
3010 } else {
3011 return -EMSGSIZE;
3012 }
3013
3014 return 0;
3015}
3016EXPORT_SYMBOL_GPL(skb_append_pagefrags);
3017
Herbert Xucbb042f92006-03-20 22:43:56 -08003018/**
Linus Lüssing9b368812016-02-24 04:21:42 +01003019 * skb_push_rcsum - push skb and update receive checksum
3020 * @skb: buffer to update
3021 * @len: length of data pulled
3022 *
3023 * This function performs an skb_push on the packet and updates
3024 * the CHECKSUM_COMPLETE checksum. It should be used on
3025 * receive path processing instead of skb_push unless you know
3026 * that the checksum difference is zero (e.g., a valid IP header)
3027 * or you are setting ip_summed to CHECKSUM_NONE.
3028 */
3029static unsigned char *skb_push_rcsum(struct sk_buff *skb, unsigned len)
3030{
3031 skb_push(skb, len);
3032 skb_postpush_rcsum(skb, skb->data, len);
3033 return skb->data;
3034}
3035
3036/**
Herbert Xucbb042f92006-03-20 22:43:56 -08003037 * skb_pull_rcsum - pull skb and update receive checksum
3038 * @skb: buffer to update
Herbert Xucbb042f92006-03-20 22:43:56 -08003039 * @len: length of data pulled
3040 *
3041 * This function performs an skb_pull on the packet and updates
Urs Thuermannfee54fa2008-02-12 22:03:25 -08003042 * the CHECKSUM_COMPLETE checksum. It should be used on
Patrick McHardy84fa7932006-08-29 16:44:56 -07003043 * receive path processing instead of skb_pull unless you know
3044 * that the checksum difference is zero (e.g., a valid IP header)
3045 * or you are setting ip_summed to CHECKSUM_NONE.
Herbert Xucbb042f92006-03-20 22:43:56 -08003046 */
3047unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
3048{
Pravin B Shelar31b33df2015-09-28 17:24:25 -07003049 unsigned char *data = skb->data;
3050
Herbert Xucbb042f92006-03-20 22:43:56 -08003051 BUG_ON(len > skb->len);
Pravin B Shelar31b33df2015-09-28 17:24:25 -07003052 __skb_pull(skb, len);
3053 skb_postpull_rcsum(skb, data, len);
3054 return skb->data;
Herbert Xucbb042f92006-03-20 22:43:56 -08003055}
Arnaldo Carvalho de Melof94691a2006-03-20 22:47:55 -08003056EXPORT_SYMBOL_GPL(skb_pull_rcsum);
3057
Herbert Xuf4c50d92006-06-22 03:02:40 -07003058/**
3059 * skb_segment - Perform protocol segmentation on skb.
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003060 * @head_skb: buffer to segment
Herbert Xu576a30e2006-06-27 13:22:38 -07003061 * @features: features for the output path (see dev->features)
Herbert Xuf4c50d92006-06-22 03:02:40 -07003062 *
3063 * This function performs segmentation on the given skb. It returns
Ben Hutchings4c821d72008-04-13 21:52:48 -07003064 * a pointer to the first in a list of new skbs for the segments.
3065 * In case of error it returns ERR_PTR(err).
Herbert Xuf4c50d92006-06-22 03:02:40 -07003066 */
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003067struct sk_buff *skb_segment(struct sk_buff *head_skb,
3068 netdev_features_t features)
Herbert Xuf4c50d92006-06-22 03:02:40 -07003069{
3070 struct sk_buff *segs = NULL;
3071 struct sk_buff *tail = NULL;
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003072 struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003073 skb_frag_t *frag = skb_shinfo(head_skb)->frags;
3074 unsigned int mss = skb_shinfo(head_skb)->gso_size;
3075 unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
Michael S. Tsirkin1fd819e2014-03-10 19:28:08 +02003076 struct sk_buff *frag_skb = head_skb;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003077 unsigned int offset = doffset;
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003078 unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003079 unsigned int headroom;
3080 unsigned int len;
Pravin B Shelarec5f0612013-03-07 09:28:01 +00003081 __be16 proto;
3082 bool csum;
Michał Mirosław04ed3e72011-01-24 15:32:47 -08003083 int sg = !!(features & NETIF_F_SG);
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003084 int nfrags = skb_shinfo(head_skb)->nr_frags;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003085 int err = -ENOMEM;
3086 int i = 0;
3087 int pos;
Vlad Yasevich53d64712014-03-27 17:26:18 -04003088 int dummy;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003089
Wei-Chun Chao5882a072014-06-08 23:48:54 -07003090 __skb_push(head_skb, doffset);
Vlad Yasevich53d64712014-03-27 17:26:18 -04003091 proto = skb_network_protocol(head_skb, &dummy);
Pravin B Shelarec5f0612013-03-07 09:28:01 +00003092 if (unlikely(!proto))
3093 return ERR_PTR(-EINVAL);
3094
Alexander Duyckf245d072016-02-05 15:28:26 -08003095 csum = !!can_checksum_protocol(features, proto);
Tom Herbert7e2b10c2014-06-04 17:20:02 -07003096
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003097 headroom = skb_headroom(head_skb);
3098 pos = skb_headlen(head_skb);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003099
3100 do {
3101 struct sk_buff *nskb;
Michael S. Tsirkin8cb19902014-03-10 18:29:04 +02003102 skb_frag_t *nskb_frag;
Herbert Xuc8884ed2006-10-29 15:59:41 -08003103 int hsize;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003104 int size;
3105
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003106 len = head_skb->len - offset;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003107 if (len > mss)
3108 len = mss;
3109
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003110 hsize = skb_headlen(head_skb) - offset;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003111 if (hsize < 0)
3112 hsize = 0;
Herbert Xuc8884ed2006-10-29 15:59:41 -08003113 if (hsize > len || !sg)
3114 hsize = len;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003115
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003116 if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
3117 (skb_headlen(list_skb) == len || sg)) {
3118 BUG_ON(skb_headlen(list_skb) > len);
Herbert Xu89319d382008-12-15 23:26:06 -08003119
Herbert Xu9d8506c2013-11-21 11:10:04 -08003120 i = 0;
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003121 nfrags = skb_shinfo(list_skb)->nr_frags;
3122 frag = skb_shinfo(list_skb)->frags;
Michael S. Tsirkin1fd819e2014-03-10 19:28:08 +02003123 frag_skb = list_skb;
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003124 pos += skb_headlen(list_skb);
Herbert Xu9d8506c2013-11-21 11:10:04 -08003125
3126 while (pos < offset + len) {
3127 BUG_ON(i >= nfrags);
3128
Michael S. Tsirkin4e1beba2014-03-10 18:29:14 +02003129 size = skb_frag_size(frag);
Herbert Xu9d8506c2013-11-21 11:10:04 -08003130 if (pos + size > offset + len)
3131 break;
3132
3133 i++;
3134 pos += size;
Michael S. Tsirkin4e1beba2014-03-10 18:29:14 +02003135 frag++;
Herbert Xu9d8506c2013-11-21 11:10:04 -08003136 }
3137
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003138 nskb = skb_clone(list_skb, GFP_ATOMIC);
3139 list_skb = list_skb->next;
Herbert Xu89319d382008-12-15 23:26:06 -08003140
3141 if (unlikely(!nskb))
3142 goto err;
3143
Herbert Xu9d8506c2013-11-21 11:10:04 -08003144 if (unlikely(pskb_trim(nskb, len))) {
3145 kfree_skb(nskb);
3146 goto err;
3147 }
3148
Alexander Duyckec47ea82012-05-04 14:26:56 +00003149 hsize = skb_end_offset(nskb);
Herbert Xu89319d382008-12-15 23:26:06 -08003150 if (skb_cow_head(nskb, doffset + headroom)) {
3151 kfree_skb(nskb);
3152 goto err;
3153 }
3154
Alexander Duyckec47ea82012-05-04 14:26:56 +00003155 nskb->truesize += skb_end_offset(nskb) - hsize;
Herbert Xu89319d382008-12-15 23:26:06 -08003156 skb_release_head_state(nskb);
3157 __skb_push(nskb, doffset);
3158 } else {
Mel Gormanc93bdd02012-07-31 16:44:19 -07003159 nskb = __alloc_skb(hsize + doffset + headroom,
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003160 GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
Mel Gormanc93bdd02012-07-31 16:44:19 -07003161 NUMA_NO_NODE);
Herbert Xu89319d382008-12-15 23:26:06 -08003162
3163 if (unlikely(!nskb))
3164 goto err;
3165
3166 skb_reserve(nskb, headroom);
3167 __skb_put(nskb, doffset);
3168 }
Herbert Xuf4c50d92006-06-22 03:02:40 -07003169
3170 if (segs)
3171 tail->next = nskb;
3172 else
3173 segs = nskb;
3174 tail = nskb;
3175
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003176 __copy_skb_header(nskb, head_skb);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003177
Eric Dumazet030737b2013-10-19 11:42:54 -07003178 skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
Vlad Yasevichfcdfe3a2014-07-31 10:33:06 -04003179 skb_reset_mac_len(nskb);
Pravin B Shelar68c33162013-02-14 14:02:41 +00003180
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003181 skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
Pravin B Shelar68c33162013-02-14 14:02:41 +00003182 nskb->data - tnl_hlen,
3183 doffset + tnl_hlen);
Herbert Xu89319d382008-12-15 23:26:06 -08003184
Herbert Xu9d8506c2013-11-21 11:10:04 -08003185 if (nskb->len == len + doffset)
Simon Horman1cdbcb72013-05-19 15:46:49 +00003186 goto perform_csum_check;
Herbert Xu89319d382008-12-15 23:26:06 -08003187
Alexander Duyck7fbeffe2016-02-05 15:27:43 -08003188 if (!sg) {
3189 if (!nskb->remcsum_offload)
3190 nskb->ip_summed = CHECKSUM_NONE;
Alexander Duyck76443452016-02-05 15:27:37 -08003191 SKB_GSO_CB(nskb)->csum =
3192 skb_copy_and_csum_bits(head_skb, offset,
3193 skb_put(nskb, len),
3194 len, 0);
Tom Herbert7e2b10c2014-06-04 17:20:02 -07003195 SKB_GSO_CB(nskb)->csum_start =
Alexander Duyck76443452016-02-05 15:27:37 -08003196 skb_headroom(nskb) + doffset;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003197 continue;
3198 }
3199
Michael S. Tsirkin8cb19902014-03-10 18:29:04 +02003200 nskb_frag = skb_shinfo(nskb)->frags;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003201
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003202 skb_copy_from_linear_data_offset(head_skb, offset,
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -03003203 skb_put(nskb, hsize), hsize);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003204
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003205 skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags &
3206 SKBTX_SHARED_FRAG;
Eric Dumazetcef401d2013-01-25 20:34:37 +00003207
Herbert Xu9d8506c2013-11-21 11:10:04 -08003208 while (pos < offset + len) {
3209 if (i >= nfrags) {
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003210 BUG_ON(skb_headlen(list_skb));
Herbert Xu9d8506c2013-11-21 11:10:04 -08003211
3212 i = 0;
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003213 nfrags = skb_shinfo(list_skb)->nr_frags;
3214 frag = skb_shinfo(list_skb)->frags;
Michael S. Tsirkin1fd819e2014-03-10 19:28:08 +02003215 frag_skb = list_skb;
Herbert Xu9d8506c2013-11-21 11:10:04 -08003216
3217 BUG_ON(!nfrags);
3218
Michael S. Tsirkin1a4ceda2014-03-10 19:27:59 +02003219 list_skb = list_skb->next;
Herbert Xu9d8506c2013-11-21 11:10:04 -08003220 }
3221
3222 if (unlikely(skb_shinfo(nskb)->nr_frags >=
3223 MAX_SKB_FRAGS)) {
3224 net_warn_ratelimited(
3225 "skb_segment: too many frags: %u %u\n",
3226 pos, mss);
3227 goto err;
3228 }
3229
Michael S. Tsirkin1fd819e2014-03-10 19:28:08 +02003230 if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC)))
3231 goto err;
3232
Michael S. Tsirkin4e1beba2014-03-10 18:29:14 +02003233 *nskb_frag = *frag;
Michael S. Tsirkin8cb19902014-03-10 18:29:04 +02003234 __skb_frag_ref(nskb_frag);
3235 size = skb_frag_size(nskb_frag);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003236
3237 if (pos < offset) {
Michael S. Tsirkin8cb19902014-03-10 18:29:04 +02003238 nskb_frag->page_offset += offset - pos;
3239 skb_frag_size_sub(nskb_frag, offset - pos);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003240 }
3241
Herbert Xu89319d382008-12-15 23:26:06 -08003242 skb_shinfo(nskb)->nr_frags++;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003243
3244 if (pos + size <= offset + len) {
3245 i++;
Michael S. Tsirkin4e1beba2014-03-10 18:29:14 +02003246 frag++;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003247 pos += size;
3248 } else {
Michael S. Tsirkin8cb19902014-03-10 18:29:04 +02003249 skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
Herbert Xu89319d382008-12-15 23:26:06 -08003250 goto skip_fraglist;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003251 }
3252
Michael S. Tsirkin8cb19902014-03-10 18:29:04 +02003253 nskb_frag++;
Herbert Xuf4c50d92006-06-22 03:02:40 -07003254 }
3255
Herbert Xu89319d382008-12-15 23:26:06 -08003256skip_fraglist:
Herbert Xuf4c50d92006-06-22 03:02:40 -07003257 nskb->data_len = len - hsize;
3258 nskb->len += nskb->data_len;
3259 nskb->truesize += nskb->data_len;
Pravin B Shelarec5f0612013-03-07 09:28:01 +00003260
Simon Horman1cdbcb72013-05-19 15:46:49 +00003261perform_csum_check:
Alexander Duyck7fbeffe2016-02-05 15:27:43 -08003262 if (!csum) {
Alexander Duyckddff00d2016-02-05 15:27:55 -08003263 if (skb_has_shared_frag(nskb)) {
3264 err = __skb_linearize(nskb);
3265 if (err)
3266 goto err;
3267 }
Alexander Duyck7fbeffe2016-02-05 15:27:43 -08003268 if (!nskb->remcsum_offload)
3269 nskb->ip_summed = CHECKSUM_NONE;
Alexander Duyck76443452016-02-05 15:27:37 -08003270 SKB_GSO_CB(nskb)->csum =
3271 skb_checksum(nskb, doffset,
3272 nskb->len - doffset, 0);
Tom Herbert7e2b10c2014-06-04 17:20:02 -07003273 SKB_GSO_CB(nskb)->csum_start =
Alexander Duyck76443452016-02-05 15:27:37 -08003274 skb_headroom(nskb) + doffset;
Pravin B Shelarec5f0612013-03-07 09:28:01 +00003275 }
Michael S. Tsirkindf5771f2014-03-10 18:29:19 +02003276 } while ((offset += len) < head_skb->len);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003277
Eric Dumazetbec3cfd2014-10-03 20:59:19 -07003278 /* Some callers want to get the end of the list.
3279 * Put it in segs->prev to avoid walking the list.
3280 * (see validate_xmit_skb_list() for example)
3281 */
3282 segs->prev = tail;
Toshiaki Makita432c8562014-10-27 10:30:51 -07003283
3284 /* Following permits correct backpressure, for protocols
3285 * using skb_set_owner_w().
3286 * Idea is to tranfert ownership from head_skb to last segment.
3287 */
3288 if (head_skb->destructor == sock_wfree) {
3289 swap(tail->truesize, head_skb->truesize);
3290 swap(tail->destructor, head_skb->destructor);
3291 swap(tail->sk, head_skb->sk);
3292 }
Herbert Xuf4c50d92006-06-22 03:02:40 -07003293 return segs;
3294
3295err:
Eric Dumazet289dccb2013-12-20 14:29:08 -08003296 kfree_skb_list(segs);
Herbert Xuf4c50d92006-06-22 03:02:40 -07003297 return ERR_PTR(err);
3298}
Herbert Xuf4c50d92006-06-22 03:02:40 -07003299EXPORT_SYMBOL_GPL(skb_segment);
3300
Herbert Xu71d93b32008-12-15 23:42:33 -08003301int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
3302{
Eric Dumazet8a291112013-10-08 09:02:23 -07003303 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
Herbert Xu67147ba2009-05-26 18:50:22 +00003304 unsigned int offset = skb_gro_offset(skb);
3305 unsigned int headlen = skb_headlen(skb);
Eric Dumazet8a291112013-10-08 09:02:23 -07003306 unsigned int len = skb_gro_len(skb);
Eric Dumazet58025e42015-03-05 13:47:48 -08003307 struct sk_buff *lp, *p = *head;
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003308 unsigned int delta_truesize;
Herbert Xu71d93b32008-12-15 23:42:33 -08003309
Eric Dumazet8a291112013-10-08 09:02:23 -07003310 if (unlikely(p->len + len >= 65536))
Herbert Xu71d93b32008-12-15 23:42:33 -08003311 return -E2BIG;
3312
Eric Dumazet29e98242014-05-16 11:34:37 -07003313 lp = NAPI_GRO_CB(p)->last;
Eric Dumazet8a291112013-10-08 09:02:23 -07003314 pinfo = skb_shinfo(lp);
3315
3316 if (headlen <= offset) {
Herbert Xu42da6992009-05-26 18:50:19 +00003317 skb_frag_t *frag;
Herbert Xu66e92fc2009-05-26 18:50:32 +00003318 skb_frag_t *frag2;
Herbert Xu9aaa1562009-05-26 18:50:33 +00003319 int i = skbinfo->nr_frags;
3320 int nr_frags = pinfo->nr_frags + i;
Herbert Xu42da6992009-05-26 18:50:19 +00003321
Herbert Xu66e92fc2009-05-26 18:50:32 +00003322 if (nr_frags > MAX_SKB_FRAGS)
Eric Dumazet8a291112013-10-08 09:02:23 -07003323 goto merge;
Herbert Xu81705ad2009-01-29 14:19:51 +00003324
Eric Dumazet8a291112013-10-08 09:02:23 -07003325 offset -= headlen;
Herbert Xu9aaa1562009-05-26 18:50:33 +00003326 pinfo->nr_frags = nr_frags;
3327 skbinfo->nr_frags = 0;
Herbert Xuf5572062009-01-14 20:40:03 -08003328
Herbert Xu9aaa1562009-05-26 18:50:33 +00003329 frag = pinfo->frags + nr_frags;
3330 frag2 = skbinfo->frags + i;
Herbert Xu66e92fc2009-05-26 18:50:32 +00003331 do {
3332 *--frag = *--frag2;
3333 } while (--i);
3334
3335 frag->page_offset += offset;
Eric Dumazet9e903e02011-10-18 21:00:24 +00003336 skb_frag_size_sub(frag, offset);
Herbert Xu66e92fc2009-05-26 18:50:32 +00003337
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003338 /* all fragments truesize : remove (head size + sk_buff) */
Alexander Duyckec47ea82012-05-04 14:26:56 +00003339 delta_truesize = skb->truesize -
3340 SKB_TRUESIZE(skb_end_offset(skb));
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003341
Herbert Xuf5572062009-01-14 20:40:03 -08003342 skb->truesize -= skb->data_len;
3343 skb->len -= skb->data_len;
3344 skb->data_len = 0;
3345
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003346 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
Herbert Xu5d38a072009-01-04 16:13:40 -08003347 goto done;
Eric Dumazetd7e88832012-04-30 08:10:34 +00003348 } else if (skb->head_frag) {
3349 int nr_frags = pinfo->nr_frags;
3350 skb_frag_t *frag = pinfo->frags + nr_frags;
3351 struct page *page = virt_to_head_page(skb->head);
3352 unsigned int first_size = headlen - offset;
3353 unsigned int first_offset;
3354
3355 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
Eric Dumazet8a291112013-10-08 09:02:23 -07003356 goto merge;
Eric Dumazetd7e88832012-04-30 08:10:34 +00003357
3358 first_offset = skb->data -
3359 (unsigned char *)page_address(page) +
3360 offset;
3361
3362 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
3363
3364 frag->page.p = page;
3365 frag->page_offset = first_offset;
3366 skb_frag_size_set(frag, first_size);
3367
3368 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
3369 /* We dont need to clear skbinfo->nr_frags here */
3370
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003371 delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
Eric Dumazetd7e88832012-04-30 08:10:34 +00003372 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
3373 goto done;
Eric Dumazet8a291112013-10-08 09:02:23 -07003374 }
Herbert Xu71d93b32008-12-15 23:42:33 -08003375
3376merge:
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003377 delta_truesize = skb->truesize;
Herbert Xu67147ba2009-05-26 18:50:22 +00003378 if (offset > headlen) {
Michal Schmidtd1dc7ab2011-01-24 12:08:48 +00003379 unsigned int eat = offset - headlen;
3380
3381 skbinfo->frags[0].page_offset += eat;
Eric Dumazet9e903e02011-10-18 21:00:24 +00003382 skb_frag_size_sub(&skbinfo->frags[0], eat);
Michal Schmidtd1dc7ab2011-01-24 12:08:48 +00003383 skb->data_len -= eat;
3384 skb->len -= eat;
Herbert Xu67147ba2009-05-26 18:50:22 +00003385 offset = headlen;
Herbert Xu56035022009-02-05 21:26:52 -08003386 }
3387
Herbert Xu67147ba2009-05-26 18:50:22 +00003388 __skb_pull(skb, offset);
Herbert Xu56035022009-02-05 21:26:52 -08003389
Eric Dumazet29e98242014-05-16 11:34:37 -07003390 if (NAPI_GRO_CB(p)->last == p)
Eric Dumazet8a291112013-10-08 09:02:23 -07003391 skb_shinfo(p)->frag_list = skb;
3392 else
3393 NAPI_GRO_CB(p)->last->next = skb;
Eric Dumazetc3c7c252012-12-06 13:54:59 +00003394 NAPI_GRO_CB(p)->last = skb;
Eric Dumazetf4a775d2014-09-22 16:29:32 -07003395 __skb_header_release(skb);
Eric Dumazet8a291112013-10-08 09:02:23 -07003396 lp = p;
Herbert Xu71d93b32008-12-15 23:42:33 -08003397
Herbert Xu5d38a072009-01-04 16:13:40 -08003398done:
3399 NAPI_GRO_CB(p)->count++;
Herbert Xu37fe4732009-01-17 19:48:13 +00003400 p->data_len += len;
Eric Dumazet715dc1f2012-05-02 23:33:21 +00003401 p->truesize += delta_truesize;
Herbert Xu37fe4732009-01-17 19:48:13 +00003402 p->len += len;
Eric Dumazet8a291112013-10-08 09:02:23 -07003403 if (lp != p) {
3404 lp->data_len += len;
3405 lp->truesize += delta_truesize;
3406 lp->len += len;
3407 }
Herbert Xu71d93b32008-12-15 23:42:33 -08003408 NAPI_GRO_CB(skb)->same_flow = 1;
3409 return 0;
3410}
Herbert Xu71d93b32008-12-15 23:42:33 -08003411
Linus Torvalds1da177e2005-04-16 15:20:36 -07003412void __init skb_init(void)
3413{
3414 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
3415 sizeof(struct sk_buff),
3416 0,
Alexey Dobriyane5d679f332006-08-26 19:25:52 -07003417 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
Paul Mundt20c2df82007-07-20 10:11:58 +09003418 NULL);
David S. Millerd179cd12005-08-17 14:57:30 -07003419 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
Eric Dumazetd0bf4a92014-09-29 13:29:15 -07003420 sizeof(struct sk_buff_fclones),
David S. Millerd179cd12005-08-17 14:57:30 -07003421 0,
Alexey Dobriyane5d679f332006-08-26 19:25:52 -07003422 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
Paul Mundt20c2df82007-07-20 10:11:58 +09003423 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003424}
3425
David Howells716ea3a2007-04-02 20:19:53 -07003426/**
3427 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
3428 * @skb: Socket buffer containing the buffers to be mapped
3429 * @sg: The scatter-gather list to map into
3430 * @offset: The offset into the buffer's contents to start mapping
3431 * @len: Length of buffer space to be mapped
3432 *
3433 * Fill the specified scatter-gather list with mappings/pointers into a
3434 * region of the buffer space attached to a socket buffer.
3435 */
David S. Miller51c739d2007-10-30 21:29:29 -07003436static int
3437__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
David Howells716ea3a2007-04-02 20:19:53 -07003438{
David S. Miller1a028e52007-04-27 15:21:23 -07003439 int start = skb_headlen(skb);
3440 int i, copy = start - offset;
David S. Millerfbb398a2009-06-09 00:18:59 -07003441 struct sk_buff *frag_iter;
David Howells716ea3a2007-04-02 20:19:53 -07003442 int elt = 0;
3443
3444 if (copy > 0) {
3445 if (copy > len)
3446 copy = len;
Jens Axboe642f1492007-10-24 11:20:47 +02003447 sg_set_buf(sg, skb->data + offset, copy);
David Howells716ea3a2007-04-02 20:19:53 -07003448 elt++;
3449 if ((len -= copy) == 0)
3450 return elt;
3451 offset += copy;
3452 }
3453
3454 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
David S. Miller1a028e52007-04-27 15:21:23 -07003455 int end;
David Howells716ea3a2007-04-02 20:19:53 -07003456
Ilpo Järvinen547b7922008-07-25 21:43:18 -07003457 WARN_ON(start > offset + len);
David S. Miller1a028e52007-04-27 15:21:23 -07003458
Eric Dumazet9e903e02011-10-18 21:00:24 +00003459 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
David Howells716ea3a2007-04-02 20:19:53 -07003460 if ((copy = end - offset) > 0) {
3461 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3462
3463 if (copy > len)
3464 copy = len;
Ian Campbellea2ab692011-08-22 23:44:58 +00003465 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
Jens Axboe642f1492007-10-24 11:20:47 +02003466 frag->page_offset+offset-start);
David Howells716ea3a2007-04-02 20:19:53 -07003467 elt++;
3468 if (!(len -= copy))
3469 return elt;
3470 offset += copy;
3471 }
David S. Miller1a028e52007-04-27 15:21:23 -07003472 start = end;
David Howells716ea3a2007-04-02 20:19:53 -07003473 }
3474
David S. Millerfbb398a2009-06-09 00:18:59 -07003475 skb_walk_frags(skb, frag_iter) {
3476 int end;
David Howells716ea3a2007-04-02 20:19:53 -07003477
David S. Millerfbb398a2009-06-09 00:18:59 -07003478 WARN_ON(start > offset + len);
David Howells716ea3a2007-04-02 20:19:53 -07003479
David S. Millerfbb398a2009-06-09 00:18:59 -07003480 end = start + frag_iter->len;
3481 if ((copy = end - offset) > 0) {
3482 if (copy > len)
3483 copy = len;
3484 elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
3485 copy);
3486 if ((len -= copy) == 0)
3487 return elt;
3488 offset += copy;
David Howells716ea3a2007-04-02 20:19:53 -07003489 }
David S. Millerfbb398a2009-06-09 00:18:59 -07003490 start = end;
David Howells716ea3a2007-04-02 20:19:53 -07003491 }
3492 BUG_ON(len);
3493 return elt;
3494}
3495
Fan Du25a91d82014-01-18 09:54:23 +08003496/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
3497 * sglist without mark the sg which contain last skb data as the end.
3498 * So the caller can mannipulate sg list as will when padding new data after
3499 * the first call without calling sg_unmark_end to expend sg list.
3500 *
3501 * Scenario to use skb_to_sgvec_nomark:
3502 * 1. sg_init_table
3503 * 2. skb_to_sgvec_nomark(payload1)
3504 * 3. skb_to_sgvec_nomark(payload2)
3505 *
3506 * This is equivalent to:
3507 * 1. sg_init_table
3508 * 2. skb_to_sgvec(payload1)
3509 * 3. sg_unmark_end
3510 * 4. skb_to_sgvec(payload2)
3511 *
3512 * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
3513 * is more preferable.
3514 */
3515int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
3516 int offset, int len)
3517{
3518 return __skb_to_sgvec(skb, sg, offset, len);
3519}
3520EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
3521
David S. Miller51c739d2007-10-30 21:29:29 -07003522int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3523{
3524 int nsg = __skb_to_sgvec(skb, sg, offset, len);
3525
Jens Axboec46f2332007-10-31 12:06:37 +01003526 sg_mark_end(&sg[nsg - 1]);
David S. Miller51c739d2007-10-30 21:29:29 -07003527
3528 return nsg;
3529}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08003530EXPORT_SYMBOL_GPL(skb_to_sgvec);
David S. Miller51c739d2007-10-30 21:29:29 -07003531
David Howells716ea3a2007-04-02 20:19:53 -07003532/**
3533 * skb_cow_data - Check that a socket buffer's data buffers are writable
3534 * @skb: The socket buffer to check.
3535 * @tailbits: Amount of trailing space to be added
3536 * @trailer: Returned pointer to the skb where the @tailbits space begins
3537 *
3538 * Make sure that the data buffers attached to a socket buffer are
3539 * writable. If they are not, private copies are made of the data buffers
3540 * and the socket buffer is set to use these instead.
3541 *
3542 * If @tailbits is given, make sure that there is space to write @tailbits
3543 * bytes of data beyond current end of socket buffer. @trailer will be
3544 * set to point to the skb in which this space begins.
3545 *
3546 * The number of scatterlist elements required to completely map the
3547 * COW'd and extended socket buffer will be returned.
3548 */
3549int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
3550{
3551 int copyflag;
3552 int elt;
3553 struct sk_buff *skb1, **skb_p;
3554
3555 /* If skb is cloned or its head is paged, reallocate
3556 * head pulling out all the pages (pages are considered not writable
3557 * at the moment even if they are anonymous).
3558 */
3559 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
3560 __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
3561 return -ENOMEM;
3562
3563 /* Easy case. Most of packets will go this way. */
David S. Miller21dc3302010-08-23 00:13:46 -07003564 if (!skb_has_frag_list(skb)) {
David Howells716ea3a2007-04-02 20:19:53 -07003565 /* A little of trouble, not enough of space for trailer.
3566 * This should not happen, when stack is tuned to generate
3567 * good frames. OK, on miss we reallocate and reserve even more
3568 * space, 128 bytes is fair. */
3569
3570 if (skb_tailroom(skb) < tailbits &&
3571 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
3572 return -ENOMEM;
3573
3574 /* Voila! */
3575 *trailer = skb;
3576 return 1;
3577 }
3578
3579 /* Misery. We are in troubles, going to mincer fragments... */
3580
3581 elt = 1;
3582 skb_p = &skb_shinfo(skb)->frag_list;
3583 copyflag = 0;
3584
3585 while ((skb1 = *skb_p) != NULL) {
3586 int ntail = 0;
3587
3588 /* The fragment is partially pulled by someone,
3589 * this can happen on input. Copy it and everything
3590 * after it. */
3591
3592 if (skb_shared(skb1))
3593 copyflag = 1;
3594
3595 /* If the skb is the last, worry about trailer. */
3596
3597 if (skb1->next == NULL && tailbits) {
3598 if (skb_shinfo(skb1)->nr_frags ||
David S. Miller21dc3302010-08-23 00:13:46 -07003599 skb_has_frag_list(skb1) ||
David Howells716ea3a2007-04-02 20:19:53 -07003600 skb_tailroom(skb1) < tailbits)
3601 ntail = tailbits + 128;
3602 }
3603
3604 if (copyflag ||
3605 skb_cloned(skb1) ||
3606 ntail ||
3607 skb_shinfo(skb1)->nr_frags ||
David S. Miller21dc3302010-08-23 00:13:46 -07003608 skb_has_frag_list(skb1)) {
David Howells716ea3a2007-04-02 20:19:53 -07003609 struct sk_buff *skb2;
3610
3611 /* Fuck, we are miserable poor guys... */
3612 if (ntail == 0)
3613 skb2 = skb_copy(skb1, GFP_ATOMIC);
3614 else
3615 skb2 = skb_copy_expand(skb1,
3616 skb_headroom(skb1),
3617 ntail,
3618 GFP_ATOMIC);
3619 if (unlikely(skb2 == NULL))
3620 return -ENOMEM;
3621
3622 if (skb1->sk)
3623 skb_set_owner_w(skb2, skb1->sk);
3624
3625 /* Looking around. Are we still alive?
3626 * OK, link new skb, drop old one */
3627
3628 skb2->next = skb1->next;
3629 *skb_p = skb2;
3630 kfree_skb(skb1);
3631 skb1 = skb2;
3632 }
3633 elt++;
3634 *trailer = skb1;
3635 skb_p = &skb1->next;
3636 }
3637
3638 return elt;
3639}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08003640EXPORT_SYMBOL_GPL(skb_cow_data);
David Howells716ea3a2007-04-02 20:19:53 -07003641
Eric Dumazetb1faf562010-05-31 23:44:05 -07003642static void sock_rmem_free(struct sk_buff *skb)
3643{
3644 struct sock *sk = skb->sk;
3645
3646 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
3647}
3648
3649/*
3650 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
3651 */
3652int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
3653{
3654 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
Eric Dumazet95c96172012-04-15 05:58:06 +00003655 (unsigned int)sk->sk_rcvbuf)
Eric Dumazetb1faf562010-05-31 23:44:05 -07003656 return -ENOMEM;
3657
3658 skb_orphan(skb);
3659 skb->sk = sk;
3660 skb->destructor = sock_rmem_free;
3661 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
3662
Eric Dumazetabb57ea2011-05-18 02:21:31 -04003663 /* before exiting rcu section, make sure dst is refcounted */
3664 skb_dst_force(skb);
3665
Eric Dumazetb1faf562010-05-31 23:44:05 -07003666 skb_queue_tail(&sk->sk_error_queue, skb);
3667 if (!sock_flag(sk, SOCK_DEAD))
David S. Miller676d2362014-04-11 16:15:36 -04003668 sk->sk_data_ready(sk);
Eric Dumazetb1faf562010-05-31 23:44:05 -07003669 return 0;
3670}
3671EXPORT_SYMBOL(sock_queue_err_skb);
3672
Willem de Bruijn364a9e92014-08-31 21:30:27 -04003673struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
3674{
3675 struct sk_buff_head *q = &sk->sk_error_queue;
3676 struct sk_buff *skb, *skb_next;
Eric Dumazet997d5c32015-02-18 05:47:55 -08003677 unsigned long flags;
Willem de Bruijn364a9e92014-08-31 21:30:27 -04003678 int err = 0;
3679
Eric Dumazet997d5c32015-02-18 05:47:55 -08003680 spin_lock_irqsave(&q->lock, flags);
Willem de Bruijn364a9e92014-08-31 21:30:27 -04003681 skb = __skb_dequeue(q);
3682 if (skb && (skb_next = skb_peek(q)))
3683 err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
Eric Dumazet997d5c32015-02-18 05:47:55 -08003684 spin_unlock_irqrestore(&q->lock, flags);
Willem de Bruijn364a9e92014-08-31 21:30:27 -04003685
3686 sk->sk_err = err;
3687 if (err)
3688 sk->sk_error_report(sk);
3689
3690 return skb;
3691}
3692EXPORT_SYMBOL(sock_dequeue_err_skb);
3693
Alexander Duyckcab41c42014-09-10 18:05:26 -04003694/**
3695 * skb_clone_sk - create clone of skb, and take reference to socket
3696 * @skb: the skb to clone
3697 *
3698 * This function creates a clone of a buffer that holds a reference on
3699 * sk_refcnt. Buffers created via this function are meant to be
3700 * returned using sock_queue_err_skb, or free via kfree_skb.
3701 *
3702 * When passing buffers allocated with this function to sock_queue_err_skb
3703 * it is necessary to wrap the call with sock_hold/sock_put in order to
3704 * prevent the socket from being released prior to being enqueued on
3705 * the sk_error_queue.
3706 */
Alexander Duyck62bccb82014-09-04 13:31:35 -04003707struct sk_buff *skb_clone_sk(struct sk_buff *skb)
3708{
3709 struct sock *sk = skb->sk;
3710 struct sk_buff *clone;
3711
3712 if (!sk || !atomic_inc_not_zero(&sk->sk_refcnt))
3713 return NULL;
3714
3715 clone = skb_clone(skb, GFP_ATOMIC);
3716 if (!clone) {
3717 sock_put(sk);
3718 return NULL;
3719 }
3720
3721 clone->sk = sk;
3722 clone->destructor = sock_efree;
3723
3724 return clone;
3725}
3726EXPORT_SYMBOL(skb_clone_sk);
3727
Alexander Duyck37846ef2014-09-04 13:31:10 -04003728static void __skb_complete_tx_timestamp(struct sk_buff *skb,
3729 struct sock *sk,
3730 int tstype)
Patrick Ohlyac45f602009-02-12 05:03:37 +00003731{
Patrick Ohlyac45f602009-02-12 05:03:37 +00003732 struct sock_exterr_skb *serr;
Patrick Ohlyac45f602009-02-12 05:03:37 +00003733 int err;
3734
Patrick Ohlyac45f602009-02-12 05:03:37 +00003735 serr = SKB_EXT_ERR(skb);
3736 memset(serr, 0, sizeof(*serr));
3737 serr->ee.ee_errno = ENOMSG;
3738 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
Willem de Bruijne7fd2882014-08-04 22:11:48 -04003739 serr->ee.ee_info = tstype;
Willem de Bruijn4ed2d762014-08-04 22:11:49 -04003740 if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
Willem de Bruijn09c2d252014-08-04 22:11:47 -04003741 serr->ee.ee_data = skb_shinfo(skb)->tskey;
WANG Congac5cc972015-12-16 23:39:04 -08003742 if (sk->sk_protocol == IPPROTO_TCP &&
3743 sk->sk_type == SOCK_STREAM)
Willem de Bruijn4ed2d762014-08-04 22:11:49 -04003744 serr->ee.ee_data -= sk->sk_tskey;
3745 }
Eric Dumazet29030372010-05-29 00:20:48 -07003746
Patrick Ohlyac45f602009-02-12 05:03:37 +00003747 err = sock_queue_err_skb(sk, skb);
Eric Dumazet29030372010-05-29 00:20:48 -07003748
Patrick Ohlyac45f602009-02-12 05:03:37 +00003749 if (err)
3750 kfree_skb(skb);
3751}
Alexander Duyck37846ef2014-09-04 13:31:10 -04003752
Willem de Bruijnb245be12015-01-30 13:29:32 -05003753static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
3754{
3755 bool ret;
3756
3757 if (likely(sysctl_tstamp_allow_data || tsonly))
3758 return true;
3759
3760 read_lock_bh(&sk->sk_callback_lock);
3761 ret = sk->sk_socket && sk->sk_socket->file &&
3762 file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
3763 read_unlock_bh(&sk->sk_callback_lock);
3764 return ret;
3765}
3766
Alexander Duyck37846ef2014-09-04 13:31:10 -04003767void skb_complete_tx_timestamp(struct sk_buff *skb,
3768 struct skb_shared_hwtstamps *hwtstamps)
3769{
3770 struct sock *sk = skb->sk;
3771
Willem de Bruijnb245be12015-01-30 13:29:32 -05003772 if (!skb_may_tx_timestamp(sk, false))
3773 return;
3774
Alexander Duyck62bccb82014-09-04 13:31:35 -04003775 /* take a reference to prevent skb_orphan() from freeing the socket */
3776 sock_hold(sk);
Alexander Duyck37846ef2014-09-04 13:31:10 -04003777
Alexander Duyck62bccb82014-09-04 13:31:35 -04003778 *skb_hwtstamps(skb) = *hwtstamps;
3779 __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND);
Alexander Duyck37846ef2014-09-04 13:31:10 -04003780
3781 sock_put(sk);
3782}
3783EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
3784
3785void __skb_tstamp_tx(struct sk_buff *orig_skb,
3786 struct skb_shared_hwtstamps *hwtstamps,
3787 struct sock *sk, int tstype)
3788{
3789 struct sk_buff *skb;
Willem de Bruijn3a8dd972015-03-11 15:43:55 -04003790 bool tsonly;
Alexander Duyck37846ef2014-09-04 13:31:10 -04003791
Willem de Bruijn3a8dd972015-03-11 15:43:55 -04003792 if (!sk)
3793 return;
3794
3795 tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
3796 if (!skb_may_tx_timestamp(sk, tsonly))
Alexander Duyck37846ef2014-09-04 13:31:10 -04003797 return;
3798
Willem de Bruijn49ca0d82015-01-30 13:29:31 -05003799 if (tsonly)
3800 skb = alloc_skb(0, GFP_ATOMIC);
Alexander Duyck37846ef2014-09-04 13:31:10 -04003801 else
Willem de Bruijn49ca0d82015-01-30 13:29:31 -05003802 skb = skb_clone(orig_skb, GFP_ATOMIC);
Alexander Duyck37846ef2014-09-04 13:31:10 -04003803 if (!skb)
3804 return;
3805
Willem de Bruijn49ca0d82015-01-30 13:29:31 -05003806 if (tsonly) {
3807 skb_shinfo(skb)->tx_flags = skb_shinfo(orig_skb)->tx_flags;
3808 skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
3809 }
3810
3811 if (hwtstamps)
3812 *skb_hwtstamps(skb) = *hwtstamps;
3813 else
3814 skb->tstamp = ktime_get_real();
3815
Alexander Duyck37846ef2014-09-04 13:31:10 -04003816 __skb_complete_tx_timestamp(skb, sk, tstype);
3817}
Willem de Bruijne7fd2882014-08-04 22:11:48 -04003818EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
3819
3820void skb_tstamp_tx(struct sk_buff *orig_skb,
3821 struct skb_shared_hwtstamps *hwtstamps)
3822{
3823 return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk,
3824 SCM_TSTAMP_SND);
3825}
Patrick Ohlyac45f602009-02-12 05:03:37 +00003826EXPORT_SYMBOL_GPL(skb_tstamp_tx);
3827
Johannes Berg6e3e9392011-11-09 10:15:42 +01003828void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
3829{
3830 struct sock *sk = skb->sk;
3831 struct sock_exterr_skb *serr;
3832 int err;
3833
3834 skb->wifi_acked_valid = 1;
3835 skb->wifi_acked = acked;
3836
3837 serr = SKB_EXT_ERR(skb);
3838 memset(serr, 0, sizeof(*serr));
3839 serr->ee.ee_errno = ENOMSG;
3840 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
3841
Alexander Duyckbf7fa552014-09-10 18:05:42 -04003842 /* take a reference to prevent skb_orphan() from freeing the socket */
3843 sock_hold(sk);
3844
Johannes Berg6e3e9392011-11-09 10:15:42 +01003845 err = sock_queue_err_skb(sk, skb);
3846 if (err)
3847 kfree_skb(skb);
Alexander Duyckbf7fa552014-09-10 18:05:42 -04003848
3849 sock_put(sk);
Johannes Berg6e3e9392011-11-09 10:15:42 +01003850}
3851EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
3852
Rusty Russellf35d9d82008-02-04 23:49:54 -05003853/**
3854 * skb_partial_csum_set - set up and verify partial csum values for packet
3855 * @skb: the skb to set
3856 * @start: the number of bytes after skb->data to start checksumming.
3857 * @off: the offset from start to place the checksum.
3858 *
3859 * For untrusted partially-checksummed packets, we need to make sure the values
3860 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
3861 *
3862 * This function checks and sets those values and skb->ip_summed: if this
3863 * returns false you should drop the packet.
3864 */
3865bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
3866{
Herbert Xu5ff8dda2009-06-04 01:22:01 +00003867 if (unlikely(start > skb_headlen(skb)) ||
3868 unlikely((int)start + off > skb_headlen(skb) - 2)) {
Joe Perchese87cc472012-05-13 21:56:26 +00003869 net_warn_ratelimited("bad partial csum: csum=%u/%u len=%u\n",
3870 start, off, skb_headlen(skb));
Rusty Russellf35d9d82008-02-04 23:49:54 -05003871 return false;
3872 }
3873 skb->ip_summed = CHECKSUM_PARTIAL;
3874 skb->csum_start = skb_headroom(skb) + start;
3875 skb->csum_offset = off;
Jason Wange5d5dec2013-03-26 23:11:20 +00003876 skb_set_transport_header(skb, start);
Rusty Russellf35d9d82008-02-04 23:49:54 -05003877 return true;
3878}
David S. Millerb4ac530fc2009-02-10 02:09:24 -08003879EXPORT_SYMBOL_GPL(skb_partial_csum_set);
Rusty Russellf35d9d82008-02-04 23:49:54 -05003880
Paul Durranted1f50c2014-01-09 10:02:46 +00003881static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
3882 unsigned int max)
3883{
3884 if (skb_headlen(skb) >= len)
3885 return 0;
3886
3887 /* If we need to pullup then pullup to the max, so we
3888 * won't need to do it again.
3889 */
3890 if (max > skb->len)
3891 max = skb->len;
3892
3893 if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
3894 return -ENOMEM;
3895
3896 if (skb_headlen(skb) < len)
3897 return -EPROTO;
3898
3899 return 0;
3900}
3901
Jan Beulichf9708b42014-03-11 13:56:05 +00003902#define MAX_TCP_HDR_LEN (15 * 4)
3903
3904static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
3905 typeof(IPPROTO_IP) proto,
3906 unsigned int off)
3907{
3908 switch (proto) {
3909 int err;
3910
3911 case IPPROTO_TCP:
3912 err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
3913 off + MAX_TCP_HDR_LEN);
3914 if (!err && !skb_partial_csum_set(skb, off,
3915 offsetof(struct tcphdr,
3916 check)))
3917 err = -EPROTO;
3918 return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
3919
3920 case IPPROTO_UDP:
3921 err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
3922 off + sizeof(struct udphdr));
3923 if (!err && !skb_partial_csum_set(skb, off,
3924 offsetof(struct udphdr,
3925 check)))
3926 err = -EPROTO;
3927 return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
3928 }
3929
3930 return ERR_PTR(-EPROTO);
3931}
3932
Paul Durranted1f50c2014-01-09 10:02:46 +00003933/* This value should be large enough to cover a tagged ethernet header plus
3934 * maximally sized IP and TCP or UDP headers.
3935 */
3936#define MAX_IP_HDR_LEN 128
3937
Jan Beulichf9708b42014-03-11 13:56:05 +00003938static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
Paul Durranted1f50c2014-01-09 10:02:46 +00003939{
3940 unsigned int off;
3941 bool fragment;
Jan Beulichf9708b42014-03-11 13:56:05 +00003942 __sum16 *csum;
Paul Durranted1f50c2014-01-09 10:02:46 +00003943 int err;
3944
3945 fragment = false;
3946
3947 err = skb_maybe_pull_tail(skb,
3948 sizeof(struct iphdr),
3949 MAX_IP_HDR_LEN);
3950 if (err < 0)
3951 goto out;
3952
3953 if (ip_hdr(skb)->frag_off & htons(IP_OFFSET | IP_MF))
3954 fragment = true;
3955
3956 off = ip_hdrlen(skb);
3957
3958 err = -EPROTO;
3959
3960 if (fragment)
3961 goto out;
3962
Jan Beulichf9708b42014-03-11 13:56:05 +00003963 csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
3964 if (IS_ERR(csum))
3965 return PTR_ERR(csum);
Paul Durranted1f50c2014-01-09 10:02:46 +00003966
Jan Beulichf9708b42014-03-11 13:56:05 +00003967 if (recalculate)
3968 *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
3969 ip_hdr(skb)->daddr,
3970 skb->len - off,
3971 ip_hdr(skb)->protocol, 0);
Paul Durranted1f50c2014-01-09 10:02:46 +00003972 err = 0;
3973
3974out:
3975 return err;
3976}
3977
3978/* This value should be large enough to cover a tagged ethernet header plus
3979 * an IPv6 header, all options, and a maximal TCP or UDP header.
3980 */
3981#define MAX_IPV6_HDR_LEN 256
3982
3983#define OPT_HDR(type, skb, off) \
3984 (type *)(skb_network_header(skb) + (off))
3985
3986static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
3987{
3988 int err;
3989 u8 nexthdr;
3990 unsigned int off;
3991 unsigned int len;
3992 bool fragment;
3993 bool done;
Jan Beulichf9708b42014-03-11 13:56:05 +00003994 __sum16 *csum;
Paul Durranted1f50c2014-01-09 10:02:46 +00003995
3996 fragment = false;
3997 done = false;
3998
3999 off = sizeof(struct ipv6hdr);
4000
4001 err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
4002 if (err < 0)
4003 goto out;
4004
4005 nexthdr = ipv6_hdr(skb)->nexthdr;
4006
4007 len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
4008 while (off <= len && !done) {
4009 switch (nexthdr) {
4010 case IPPROTO_DSTOPTS:
4011 case IPPROTO_HOPOPTS:
4012 case IPPROTO_ROUTING: {
4013 struct ipv6_opt_hdr *hp;
4014
4015 err = skb_maybe_pull_tail(skb,
4016 off +
4017 sizeof(struct ipv6_opt_hdr),
4018 MAX_IPV6_HDR_LEN);
4019 if (err < 0)
4020 goto out;
4021
4022 hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
4023 nexthdr = hp->nexthdr;
4024 off += ipv6_optlen(hp);
4025 break;
4026 }
4027 case IPPROTO_AH: {
4028 struct ip_auth_hdr *hp;
4029
4030 err = skb_maybe_pull_tail(skb,
4031 off +
4032 sizeof(struct ip_auth_hdr),
4033 MAX_IPV6_HDR_LEN);
4034 if (err < 0)
4035 goto out;
4036
4037 hp = OPT_HDR(struct ip_auth_hdr, skb, off);
4038 nexthdr = hp->nexthdr;
4039 off += ipv6_authlen(hp);
4040 break;
4041 }
4042 case IPPROTO_FRAGMENT: {
4043 struct frag_hdr *hp;
4044
4045 err = skb_maybe_pull_tail(skb,
4046 off +
4047 sizeof(struct frag_hdr),
4048 MAX_IPV6_HDR_LEN);
4049 if (err < 0)
4050 goto out;
4051
4052 hp = OPT_HDR(struct frag_hdr, skb, off);
4053
4054 if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
4055 fragment = true;
4056
4057 nexthdr = hp->nexthdr;
4058 off += sizeof(struct frag_hdr);
4059 break;
4060 }
4061 default:
4062 done = true;
4063 break;
4064 }
4065 }
4066
4067 err = -EPROTO;
4068
4069 if (!done || fragment)
4070 goto out;
4071
Jan Beulichf9708b42014-03-11 13:56:05 +00004072 csum = skb_checksum_setup_ip(skb, nexthdr, off);
4073 if (IS_ERR(csum))
4074 return PTR_ERR(csum);
Paul Durranted1f50c2014-01-09 10:02:46 +00004075
Jan Beulichf9708b42014-03-11 13:56:05 +00004076 if (recalculate)
4077 *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
4078 &ipv6_hdr(skb)->daddr,
4079 skb->len - off, nexthdr, 0);
Paul Durranted1f50c2014-01-09 10:02:46 +00004080 err = 0;
4081
4082out:
4083 return err;
4084}
4085
4086/**
4087 * skb_checksum_setup - set up partial checksum offset
4088 * @skb: the skb to set up
4089 * @recalculate: if true the pseudo-header checksum will be recalculated
4090 */
4091int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
4092{
4093 int err;
4094
4095 switch (skb->protocol) {
4096 case htons(ETH_P_IP):
Jan Beulichf9708b42014-03-11 13:56:05 +00004097 err = skb_checksum_setup_ipv4(skb, recalculate);
Paul Durranted1f50c2014-01-09 10:02:46 +00004098 break;
4099
4100 case htons(ETH_P_IPV6):
4101 err = skb_checksum_setup_ipv6(skb, recalculate);
4102 break;
4103
4104 default:
4105 err = -EPROTO;
4106 break;
4107 }
4108
4109 return err;
4110}
4111EXPORT_SYMBOL(skb_checksum_setup);
4112
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004113/**
4114 * skb_checksum_maybe_trim - maybe trims the given skb
4115 * @skb: the skb to check
4116 * @transport_len: the data length beyond the network header
4117 *
4118 * Checks whether the given skb has data beyond the given transport length.
4119 * If so, returns a cloned skb trimmed to this transport length.
4120 * Otherwise returns the provided skb. Returns NULL in error cases
4121 * (e.g. transport_len exceeds skb length or out-of-memory).
4122 *
Linus Lüssinga5169932015-08-13 05:54:07 +02004123 * Caller needs to set the skb transport header and free any returned skb if it
4124 * differs from the provided skb.
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004125 */
4126static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
4127 unsigned int transport_len)
4128{
4129 struct sk_buff *skb_chk;
4130 unsigned int len = skb_transport_offset(skb) + transport_len;
4131 int ret;
4132
Linus Lüssinga5169932015-08-13 05:54:07 +02004133 if (skb->len < len)
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004134 return NULL;
Linus Lüssinga5169932015-08-13 05:54:07 +02004135 else if (skb->len == len)
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004136 return skb;
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004137
4138 skb_chk = skb_clone(skb, GFP_ATOMIC);
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004139 if (!skb_chk)
4140 return NULL;
4141
4142 ret = pskb_trim_rcsum(skb_chk, len);
4143 if (ret) {
4144 kfree_skb(skb_chk);
4145 return NULL;
4146 }
4147
4148 return skb_chk;
4149}
4150
4151/**
4152 * skb_checksum_trimmed - validate checksum of an skb
4153 * @skb: the skb to check
4154 * @transport_len: the data length beyond the network header
4155 * @skb_chkf: checksum function to use
4156 *
4157 * Applies the given checksum function skb_chkf to the provided skb.
4158 * Returns a checked and maybe trimmed skb. Returns NULL on error.
4159 *
4160 * If the skb has data beyond the given transport length, then a
4161 * trimmed & cloned skb is checked and returned.
4162 *
Linus Lüssinga5169932015-08-13 05:54:07 +02004163 * Caller needs to set the skb transport header and free any returned skb if it
4164 * differs from the provided skb.
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004165 */
4166struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
4167 unsigned int transport_len,
4168 __sum16(*skb_chkf)(struct sk_buff *skb))
4169{
4170 struct sk_buff *skb_chk;
4171 unsigned int offset = skb_transport_offset(skb);
Linus Lüssingfcba67c2015-05-05 00:19:35 +02004172 __sum16 ret;
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004173
4174 skb_chk = skb_checksum_maybe_trim(skb, transport_len);
4175 if (!skb_chk)
Linus Lüssinga5169932015-08-13 05:54:07 +02004176 goto err;
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004177
Linus Lüssinga5169932015-08-13 05:54:07 +02004178 if (!pskb_may_pull(skb_chk, offset))
4179 goto err;
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004180
Linus Lüssing9b368812016-02-24 04:21:42 +01004181 skb_pull_rcsum(skb_chk, offset);
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004182 ret = skb_chkf(skb_chk);
Linus Lüssing9b368812016-02-24 04:21:42 +01004183 skb_push_rcsum(skb_chk, offset);
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004184
Linus Lüssinga5169932015-08-13 05:54:07 +02004185 if (ret)
4186 goto err;
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004187
4188 return skb_chk;
Linus Lüssinga5169932015-08-13 05:54:07 +02004189
4190err:
4191 if (skb_chk && skb_chk != skb)
4192 kfree_skb(skb_chk);
4193
4194 return NULL;
4195
Linus Lüssing9afd85c2015-05-02 14:01:07 +02004196}
4197EXPORT_SYMBOL(skb_checksum_trimmed);
4198
Ben Hutchings4497b072008-06-19 16:22:28 -07004199void __skb_warn_lro_forwarding(const struct sk_buff *skb)
4200{
Joe Perchese87cc472012-05-13 21:56:26 +00004201 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
4202 skb->dev->name);
Ben Hutchings4497b072008-06-19 16:22:28 -07004203}
Ben Hutchings4497b072008-06-19 16:22:28 -07004204EXPORT_SYMBOL(__skb_warn_lro_forwarding);
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004205
4206void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
4207{
Eric Dumazet3d861f62012-10-22 09:03:40 +00004208 if (head_stolen) {
4209 skb_release_head_state(skb);
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004210 kmem_cache_free(skbuff_head_cache, skb);
Eric Dumazet3d861f62012-10-22 09:03:40 +00004211 } else {
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004212 __kfree_skb(skb);
Eric Dumazet3d861f62012-10-22 09:03:40 +00004213 }
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004214}
4215EXPORT_SYMBOL(kfree_skb_partial);
4216
4217/**
4218 * skb_try_coalesce - try to merge skb to prior one
4219 * @to: prior buffer
4220 * @from: buffer to add
4221 * @fragstolen: pointer to boolean
Randy Dunlapc6c4b972012-06-08 14:01:44 +00004222 * @delta_truesize: how much more was allocated than was requested
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004223 */
4224bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
4225 bool *fragstolen, int *delta_truesize)
4226{
4227 int i, delta, len = from->len;
4228
4229 *fragstolen = false;
4230
4231 if (skb_cloned(to))
4232 return false;
4233
4234 if (len <= skb_tailroom(to)) {
Eric Dumazete93a0432014-09-15 04:19:52 -07004235 if (len)
4236 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004237 *delta_truesize = 0;
4238 return true;
4239 }
4240
4241 if (skb_has_frag_list(to) || skb_has_frag_list(from))
4242 return false;
4243
4244 if (skb_headlen(from) != 0) {
4245 struct page *page;
4246 unsigned int offset;
4247
4248 if (skb_shinfo(to)->nr_frags +
4249 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
4250 return false;
4251
4252 if (skb_head_is_locked(from))
4253 return false;
4254
4255 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
4256
4257 page = virt_to_head_page(from->head);
4258 offset = from->data - (unsigned char *)page_address(page);
4259
4260 skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
4261 page, offset, skb_headlen(from));
4262 *fragstolen = true;
4263 } else {
4264 if (skb_shinfo(to)->nr_frags +
4265 skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS)
4266 return false;
4267
Weiping Panf4b549a2012-09-28 20:15:30 +00004268 delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004269 }
4270
4271 WARN_ON_ONCE(delta < len);
4272
4273 memcpy(skb_shinfo(to)->frags + skb_shinfo(to)->nr_frags,
4274 skb_shinfo(from)->frags,
4275 skb_shinfo(from)->nr_frags * sizeof(skb_frag_t));
4276 skb_shinfo(to)->nr_frags += skb_shinfo(from)->nr_frags;
4277
4278 if (!skb_cloned(from))
4279 skb_shinfo(from)->nr_frags = 0;
4280
Li RongQing8ea853f2012-09-18 16:53:21 +00004281 /* if the skb is not cloned this does nothing
4282 * since we set nr_frags to 0.
4283 */
Eric Dumazetbad43ca2012-05-19 03:02:02 +00004284 for (i = 0; i < skb_shinfo(from)->nr_frags; i++)
4285 skb_frag_ref(from, i);
4286
4287 to->truesize += delta;
4288 to->len += len;
4289 to->data_len += len;
4290
4291 *delta_truesize = delta;
4292 return true;
4293}
4294EXPORT_SYMBOL(skb_try_coalesce);
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004295
4296/**
Nicolas Dichtel8b27f272013-09-02 15:34:56 +02004297 * skb_scrub_packet - scrub an skb
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004298 *
4299 * @skb: buffer to clean
Nicolas Dichtel8b27f272013-09-02 15:34:56 +02004300 * @xnet: packet is crossing netns
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004301 *
Nicolas Dichtel8b27f272013-09-02 15:34:56 +02004302 * skb_scrub_packet can be used after encapsulating or decapsulting a packet
4303 * into/from a tunnel. Some information have to be cleared during these
4304 * operations.
4305 * skb_scrub_packet can also be used to clean a skb before injecting it in
4306 * another namespace (@xnet == true). We have to clear all information in the
4307 * skb that could impact namespace isolation.
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004308 */
Nicolas Dichtel8b27f272013-09-02 15:34:56 +02004309void skb_scrub_packet(struct sk_buff *skb, bool xnet)
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004310{
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004311 skb->tstamp.tv64 = 0;
4312 skb->pkt_type = PACKET_HOST;
4313 skb->skb_iif = 0;
WANG Cong60ff7462014-05-04 16:39:18 -07004314 skb->ignore_df = 0;
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004315 skb_dst_drop(skb);
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004316 secpath_reset(skb);
4317 nf_reset(skb);
4318 nf_reset_trace(skb);
Herbert Xu213dd742015-04-16 09:03:27 +08004319
4320 if (!xnet)
4321 return;
4322
4323 skb_orphan(skb);
4324 skb->mark = 0;
Nicolas Dichtel621e84d2013-06-26 16:11:27 +02004325}
4326EXPORT_SYMBOL_GPL(skb_scrub_packet);
Florian Westphalde960aa2014-01-26 10:58:16 +01004327
4328/**
4329 * skb_gso_transport_seglen - Return length of individual segments of a gso packet
4330 *
4331 * @skb: GSO skb
4332 *
4333 * skb_gso_transport_seglen is used to determine the real size of the
4334 * individual segments, including Layer4 headers (TCP/UDP).
4335 *
4336 * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
4337 */
4338unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
4339{
4340 const struct skb_shared_info *shinfo = skb_shinfo(skb);
Florian Westphalf993bc22014-10-20 13:49:18 +02004341 unsigned int thlen = 0;
Florian Westphalde960aa2014-01-26 10:58:16 +01004342
Florian Westphalf993bc22014-10-20 13:49:18 +02004343 if (skb->encapsulation) {
4344 thlen = skb_inner_transport_header(skb) -
4345 skb_transport_header(skb);
Florian Westphal6d39d582014-04-09 10:28:50 +02004346
Florian Westphalf993bc22014-10-20 13:49:18 +02004347 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
4348 thlen += inner_tcp_hdrlen(skb);
4349 } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
4350 thlen = tcp_hdrlen(skb);
4351 }
Florian Westphal6d39d582014-04-09 10:28:50 +02004352 /* UFO sets gso_size to the size of the fragmentation
4353 * payload, i.e. the size of the L4 (UDP) header is already
4354 * accounted for.
4355 */
Florian Westphalf993bc22014-10-20 13:49:18 +02004356 return thlen + shinfo->gso_size;
Florian Westphalde960aa2014-01-26 10:58:16 +01004357}
4358EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
Vlad Yasevich0d5501c2014-08-08 14:42:13 -04004359
4360static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
4361{
4362 if (skb_cow(skb, skb_headroom(skb)) < 0) {
4363 kfree_skb(skb);
4364 return NULL;
4365 }
4366
Vlad Yasevichf6548612015-12-14 17:44:10 -05004367 memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len - VLAN_HLEN,
Vlad Yasevicha6e18ff2015-11-16 15:43:44 -05004368 2 * ETH_ALEN);
Vlad Yasevich0d5501c2014-08-08 14:42:13 -04004369 skb->mac_header += VLAN_HLEN;
4370 return skb;
4371}
4372
4373struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
4374{
4375 struct vlan_hdr *vhdr;
4376 u16 vlan_tci;
4377
Jiri Pirkodf8a39d2015-01-13 17:13:44 +01004378 if (unlikely(skb_vlan_tag_present(skb))) {
Vlad Yasevich0d5501c2014-08-08 14:42:13 -04004379 /* vlan_tci is already set-up so leave this for another time */
4380 return skb;
4381 }
4382
4383 skb = skb_share_check(skb, GFP_ATOMIC);
4384 if (unlikely(!skb))
4385 goto err_free;
4386
4387 if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
4388 goto err_free;
4389
4390 vhdr = (struct vlan_hdr *)skb->data;
4391 vlan_tci = ntohs(vhdr->h_vlan_TCI);
4392 __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
4393
4394 skb_pull_rcsum(skb, VLAN_HLEN);
4395 vlan_set_encap_proto(skb, vhdr);
4396
4397 skb = skb_reorder_vlan_header(skb);
4398 if (unlikely(!skb))
4399 goto err_free;
4400
4401 skb_reset_network_header(skb);
4402 skb_reset_transport_header(skb);
4403 skb_reset_mac_len(skb);
4404
4405 return skb;
4406
4407err_free:
4408 kfree_skb(skb);
4409 return NULL;
4410}
4411EXPORT_SYMBOL(skb_vlan_untag);
Eric Dumazet2e4e4412014-09-17 04:49:49 -07004412
Jiri Pirkoe2195122014-11-19 14:05:01 +01004413int skb_ensure_writable(struct sk_buff *skb, int write_len)
4414{
4415 if (!pskb_may_pull(skb, write_len))
4416 return -ENOMEM;
4417
4418 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
4419 return 0;
4420
4421 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
4422}
4423EXPORT_SYMBOL(skb_ensure_writable);
4424
Jiri Pirko93515d52014-11-19 14:05:02 +01004425/* remove VLAN header from packet and update csum accordingly. */
4426static int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
4427{
4428 struct vlan_hdr *vhdr;
4429 unsigned int offset = skb->data - skb_mac_header(skb);
4430 int err;
4431
4432 __skb_push(skb, offset);
4433 err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
4434 if (unlikely(err))
4435 goto pull;
4436
4437 skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
4438
4439 vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
4440 *vlan_tci = ntohs(vhdr->h_vlan_TCI);
4441
4442 memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
4443 __skb_pull(skb, VLAN_HLEN);
4444
4445 vlan_set_encap_proto(skb, vhdr);
4446 skb->mac_header += VLAN_HLEN;
4447
4448 if (skb_network_offset(skb) < ETH_HLEN)
4449 skb_set_network_header(skb, ETH_HLEN);
4450
4451 skb_reset_mac_len(skb);
4452pull:
4453 __skb_pull(skb, offset);
4454
4455 return err;
4456}
4457
4458int skb_vlan_pop(struct sk_buff *skb)
4459{
4460 u16 vlan_tci;
4461 __be16 vlan_proto;
4462 int err;
4463
Jiri Pirkodf8a39d2015-01-13 17:13:44 +01004464 if (likely(skb_vlan_tag_present(skb))) {
Jiri Pirko93515d52014-11-19 14:05:02 +01004465 skb->vlan_tci = 0;
4466 } else {
4467 if (unlikely((skb->protocol != htons(ETH_P_8021Q) &&
4468 skb->protocol != htons(ETH_P_8021AD)) ||
4469 skb->len < VLAN_ETH_HLEN))
4470 return 0;
4471
4472 err = __skb_vlan_pop(skb, &vlan_tci);
4473 if (err)
4474 return err;
4475 }
4476 /* move next vlan tag to hw accel tag */
4477 if (likely((skb->protocol != htons(ETH_P_8021Q) &&
4478 skb->protocol != htons(ETH_P_8021AD)) ||
4479 skb->len < VLAN_ETH_HLEN))
4480 return 0;
4481
4482 vlan_proto = skb->protocol;
4483 err = __skb_vlan_pop(skb, &vlan_tci);
4484 if (unlikely(err))
4485 return err;
4486
4487 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
4488 return 0;
4489}
4490EXPORT_SYMBOL(skb_vlan_pop);
4491
4492int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
4493{
Jiri Pirkodf8a39d2015-01-13 17:13:44 +01004494 if (skb_vlan_tag_present(skb)) {
Jiri Pirko93515d52014-11-19 14:05:02 +01004495 unsigned int offset = skb->data - skb_mac_header(skb);
4496 int err;
4497
4498 /* __vlan_insert_tag expect skb->data pointing to mac header.
4499 * So change skb->data before calling it and change back to
4500 * original position later
4501 */
4502 __skb_push(skb, offset);
4503 err = __vlan_insert_tag(skb, skb->vlan_proto,
Jiri Pirkodf8a39d2015-01-13 17:13:44 +01004504 skb_vlan_tag_get(skb));
Daniel Borkmann9241e2d2016-04-16 02:27:58 +02004505 if (err) {
4506 __skb_pull(skb, offset);
Jiri Pirko93515d52014-11-19 14:05:02 +01004507 return err;
Daniel Borkmann9241e2d2016-04-16 02:27:58 +02004508 }
4509
Jiri Pirko93515d52014-11-19 14:05:02 +01004510 skb->protocol = skb->vlan_proto;
4511 skb->mac_len += VLAN_HLEN;
Jiri Pirko93515d52014-11-19 14:05:02 +01004512
Daniel Borkmann6b83d282016-02-20 00:29:30 +01004513 skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
Daniel Borkmann9241e2d2016-04-16 02:27:58 +02004514 __skb_pull(skb, offset);
Jiri Pirko93515d52014-11-19 14:05:02 +01004515 }
4516 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
4517 return 0;
4518}
4519EXPORT_SYMBOL(skb_vlan_push);
4520
Eric Dumazet2e4e4412014-09-17 04:49:49 -07004521/**
4522 * alloc_skb_with_frags - allocate skb with page frags
4523 *
Masanari Iidade3f0d02014-10-09 12:58:08 +09004524 * @header_len: size of linear part
4525 * @data_len: needed length in frags
4526 * @max_page_order: max page order desired.
4527 * @errcode: pointer to error code if any
4528 * @gfp_mask: allocation mask
Eric Dumazet2e4e4412014-09-17 04:49:49 -07004529 *
4530 * This can be used to allocate a paged skb, given a maximal order for frags.
4531 */
4532struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
4533 unsigned long data_len,
4534 int max_page_order,
4535 int *errcode,
4536 gfp_t gfp_mask)
4537{
4538 int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
4539 unsigned long chunk;
4540 struct sk_buff *skb;
4541 struct page *page;
4542 gfp_t gfp_head;
4543 int i;
4544
4545 *errcode = -EMSGSIZE;
4546 /* Note this test could be relaxed, if we succeed to allocate
4547 * high order pages...
4548 */
4549 if (npages > MAX_SKB_FRAGS)
4550 return NULL;
4551
4552 gfp_head = gfp_mask;
Mel Gormand0164ad2015-11-06 16:28:21 -08004553 if (gfp_head & __GFP_DIRECT_RECLAIM)
Eric Dumazet2e4e4412014-09-17 04:49:49 -07004554 gfp_head |= __GFP_REPEAT;
4555
4556 *errcode = -ENOBUFS;
4557 skb = alloc_skb(header_len, gfp_head);
4558 if (!skb)
4559 return NULL;
4560
4561 skb->truesize += npages << PAGE_SHIFT;
4562
4563 for (i = 0; npages > 0; i++) {
4564 int order = max_page_order;
4565
4566 while (order) {
4567 if (npages >= 1 << order) {
Mel Gormand0164ad2015-11-06 16:28:21 -08004568 page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
Eric Dumazet2e4e4412014-09-17 04:49:49 -07004569 __GFP_COMP |
4570 __GFP_NOWARN |
4571 __GFP_NORETRY,
4572 order);
4573 if (page)
4574 goto fill_page;
4575 /* Do not retry other high order allocations */
4576 order = 1;
4577 max_page_order = 0;
4578 }
4579 order--;
4580 }
4581 page = alloc_page(gfp_mask);
4582 if (!page)
4583 goto failure;
4584fill_page:
4585 chunk = min_t(unsigned long, data_len,
4586 PAGE_SIZE << order);
4587 skb_fill_page_desc(skb, i, page, 0, chunk);
4588 data_len -= chunk;
4589 npages -= 1 << order;
4590 }
4591 return skb;
4592
4593failure:
4594 kfree_skb(skb);
4595 return NULL;
4596}
4597EXPORT_SYMBOL(alloc_skb_with_frags);