]>
Commit | Line | Data |
---|---|---|
2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Routines having to do with the 'struct sk_buff' memory handlers. | |
4 | * | |
113aa838 | 5 | * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
6 | * Florian La Roche <rzsfl@rz.uni-sb.de> |
7 | * | |
1da177e4 LT |
8 | * Fixes: |
9 | * Alan Cox : Fixed the worst of the load | |
10 | * balancer bugs. | |
11 | * Dave Platt : Interrupt stacking fix. | |
12 | * Richard Kooijman : Timestamp fixes. | |
13 | * Alan Cox : Changed buffer format. | |
14 | * Alan Cox : destructor hook for AF_UNIX etc. | |
15 | * Linus Torvalds : Better skb_clone. | |
16 | * Alan Cox : Added skb_copy. | |
17 | * Alan Cox : Added all the changed routines Linus | |
18 | * only put in the headers | |
19 | * Ray VanTassle : Fixed --skb->lock in free | |
20 | * Alan Cox : skb_copy copy arp field | |
21 | * Andi Kleen : slabified it. | |
22 | * Robert Olsson : Removed skb_head_pool | |
23 | * | |
24 | * NOTE: | |
25 | * The __skb_ routines should be called with interrupts | |
26 | * disabled, or you better be *real* sure that the operation is atomic | |
27 | * with respect to whatever list is being frobbed (e.g. via lock_sock() | |
28 | * or via disabling bottom half handlers, etc). | |
1da177e4 LT |
29 | */ |
30 | ||
31 | /* | |
32 | * The functions in this file will not compile correctly with gcc 2.4.x | |
33 | */ | |
34 | ||
e005d193 JP |
35 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
36 | ||
1da177e4 LT |
37 | #include <linux/module.h> |
38 | #include <linux/types.h> | |
39 | #include <linux/kernel.h> | |
1da177e4 LT |
40 | #include <linux/mm.h> |
41 | #include <linux/interrupt.h> | |
42 | #include <linux/in.h> | |
43 | #include <linux/inet.h> | |
44 | #include <linux/slab.h> | |
de960aa9 FW |
45 | #include <linux/tcp.h> |
46 | #include <linux/udp.h> | |
90017acc | 47 | #include <linux/sctp.h> |
1da177e4 LT |
48 | #include <linux/netdevice.h> |
49 | #ifdef CONFIG_NET_CLS_ACT | |
50 | #include <net/pkt_sched.h> | |
51 | #endif | |
52 | #include <linux/string.h> | |
53 | #include <linux/skbuff.h> | |
9c55e01c | 54 | #include <linux/splice.h> |
1da177e4 LT |
55 | #include <linux/cache.h> |
56 | #include <linux/rtnetlink.h> | |
57 | #include <linux/init.h> | |
716ea3a7 | 58 | #include <linux/scatterlist.h> |
ac45f602 | 59 | #include <linux/errqueue.h> |
268bb0ce | 60 | #include <linux/prefetch.h> |
0d5501c1 | 61 | #include <linux/if_vlan.h> |
1da177e4 LT |
62 | |
63 | #include <net/protocol.h> | |
64 | #include <net/dst.h> | |
65 | #include <net/sock.h> | |
66 | #include <net/checksum.h> | |
ed1f50c3 | 67 | #include <net/ip6_checksum.h> |
1da177e4 LT |
68 | #include <net/xfrm.h> |
69 | ||
7c0f6ba6 | 70 | #include <linux/uaccess.h> |
ad8d75ff | 71 | #include <trace/events/skb.h> |
51c56b00 | 72 | #include <linux/highmem.h> |
b245be1f WB |
73 | #include <linux/capability.h> |
74 | #include <linux/user_namespace.h> | |
a1f8e7f7 | 75 | |
7b7ed885 BVA |
76 | #include "datagram.h" |
77 | ||
08009a76 AD |
78 | struct kmem_cache *skbuff_head_cache __ro_after_init; |
79 | static struct kmem_cache *skbuff_fclone_cache __ro_after_init; | |
df5042f4 FW |
80 | #ifdef CONFIG_SKB_EXTENSIONS |
81 | static struct kmem_cache *skbuff_ext_cache __ro_after_init; | |
82 | #endif | |
5f74f82e HWR |
83 | int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS; |
84 | EXPORT_SYMBOL(sysctl_max_skb_frags); | |
1da177e4 | 85 | |
1da177e4 | 86 | /** |
f05de73b JS |
87 | * skb_panic - private function for out-of-line support |
88 | * @skb: buffer | |
89 | * @sz: size | |
90 | * @addr: address | |
99d5851e | 91 | * @msg: skb_over_panic or skb_under_panic |
1da177e4 | 92 | * |
f05de73b JS |
93 | * Out-of-line support for skb_put() and skb_push(). |
94 | * Called via the wrapper skb_over_panic() or skb_under_panic(). | |
95 | * Keep out of line to prevent kernel bloat. | |
96 | * __builtin_return_address is not used because it is not always reliable. | |
1da177e4 | 97 | */ |
f05de73b | 98 | static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr, |
99d5851e | 99 | const char msg[]) |
1da177e4 | 100 | { |
e005d193 | 101 | pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n", |
99d5851e | 102 | msg, addr, skb->len, sz, skb->head, skb->data, |
e005d193 JP |
103 | (unsigned long)skb->tail, (unsigned long)skb->end, |
104 | skb->dev ? skb->dev->name : "<NULL>"); | |
1da177e4 LT |
105 | BUG(); |
106 | } | |
107 | ||
f05de73b | 108 | static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr) |
1da177e4 | 109 | { |
f05de73b | 110 | skb_panic(skb, sz, addr, __func__); |
1da177e4 LT |
111 | } |
112 | ||
f05de73b JS |
113 | static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr) |
114 | { | |
115 | skb_panic(skb, sz, addr, __func__); | |
116 | } | |
c93bdd0e MG |
117 | |
118 | /* | |
119 | * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells | |
120 | * the caller if emergency pfmemalloc reserves are being used. If it is and | |
121 | * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves | |
122 | * may be used. Otherwise, the packet data may be discarded until enough | |
123 | * memory is free | |
124 | */ | |
125 | #define kmalloc_reserve(size, gfp, node, pfmemalloc) \ | |
126 | __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc) | |
61c5e88a | 127 | |
128 | static void *__kmalloc_reserve(size_t size, gfp_t flags, int node, | |
129 | unsigned long ip, bool *pfmemalloc) | |
c93bdd0e MG |
130 | { |
131 | void *obj; | |
132 | bool ret_pfmemalloc = false; | |
133 | ||
134 | /* | |
135 | * Try a regular allocation, when that fails and we're not entitled | |
136 | * to the reserves, fail. | |
137 | */ | |
138 | obj = kmalloc_node_track_caller(size, | |
139 | flags | __GFP_NOMEMALLOC | __GFP_NOWARN, | |
140 | node); | |
141 | if (obj || !(gfp_pfmemalloc_allowed(flags))) | |
142 | goto out; | |
143 | ||
144 | /* Try again but now we are using pfmemalloc reserves */ | |
145 | ret_pfmemalloc = true; | |
146 | obj = kmalloc_node_track_caller(size, flags, node); | |
147 | ||
148 | out: | |
149 | if (pfmemalloc) | |
150 | *pfmemalloc = ret_pfmemalloc; | |
151 | ||
152 | return obj; | |
153 | } | |
154 | ||
1da177e4 LT |
155 | /* Allocate a new skbuff. We do this ourselves so we can fill in a few |
156 | * 'private' fields and also do memory statistics to find all the | |
157 | * [BEEP] leaks. | |
158 | * | |
159 | */ | |
160 | ||
161 | /** | |
d179cd12 | 162 | * __alloc_skb - allocate a network buffer |
1da177e4 LT |
163 | * @size: size to allocate |
164 | * @gfp_mask: allocation mask | |
c93bdd0e MG |
165 | * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache |
166 | * instead of head cache and allocate a cloned (child) skb. | |
167 | * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for | |
168 | * allocations in case the data is required for writeback | |
b30973f8 | 169 | * @node: numa node to allocate memory on |
1da177e4 LT |
170 | * |
171 | * Allocate a new &sk_buff. The returned buffer has no headroom and a | |
94b6042c BH |
172 | * tail room of at least size bytes. The object has a reference count |
173 | * of one. The return is the buffer. On a failure the return is %NULL. | |
1da177e4 LT |
174 | * |
175 | * Buffers may only be allocated from interrupts using a @gfp_mask of | |
176 | * %GFP_ATOMIC. | |
177 | */ | |
dd0fc66f | 178 | struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, |
c93bdd0e | 179 | int flags, int node) |
1da177e4 | 180 | { |
e18b890b | 181 | struct kmem_cache *cache; |
4947d3ef | 182 | struct skb_shared_info *shinfo; |
1da177e4 LT |
183 | struct sk_buff *skb; |
184 | u8 *data; | |
c93bdd0e | 185 | bool pfmemalloc; |
1da177e4 | 186 | |
c93bdd0e MG |
187 | cache = (flags & SKB_ALLOC_FCLONE) |
188 | ? skbuff_fclone_cache : skbuff_head_cache; | |
189 | ||
190 | if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX)) | |
191 | gfp_mask |= __GFP_MEMALLOC; | |
8798b3fb | 192 | |
1da177e4 | 193 | /* Get the HEAD */ |
b30973f8 | 194 | skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); |
1da177e4 LT |
195 | if (!skb) |
196 | goto out; | |
ec7d2f2c | 197 | prefetchw(skb); |
1da177e4 | 198 | |
87fb4b7b ED |
199 | /* We do our best to align skb_shared_info on a separate cache |
200 | * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives | |
201 | * aligned memory blocks, unless SLUB/SLAB debug is enabled. | |
202 | * Both skb->head and skb_shared_info are cache line aligned. | |
203 | */ | |
bc417e30 | 204 | size = SKB_DATA_ALIGN(size); |
87fb4b7b | 205 | size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
c93bdd0e | 206 | data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc); |
1da177e4 LT |
207 | if (!data) |
208 | goto nodata; | |
87fb4b7b ED |
209 | /* kmalloc(size) might give us more room than requested. |
210 | * Put skb_shared_info exactly at the end of allocated zone, | |
211 | * to allow max possible filling before reallocation. | |
212 | */ | |
213 | size = SKB_WITH_OVERHEAD(ksize(data)); | |
ec7d2f2c | 214 | prefetchw(data + size); |
1da177e4 | 215 | |
ca0605a7 | 216 | /* |
c8005785 JB |
217 | * Only clear those fields we need to clear, not those that we will |
218 | * actually initialise below. Hence, don't put any more fields after | |
219 | * the tail pointer in struct sk_buff! | |
ca0605a7 ACM |
220 | */ |
221 | memset(skb, 0, offsetof(struct sk_buff, tail)); | |
87fb4b7b ED |
222 | /* Account for allocated memory : skb + skb->head */ |
223 | skb->truesize = SKB_TRUESIZE(size); | |
c93bdd0e | 224 | skb->pfmemalloc = pfmemalloc; |
63354797 | 225 | refcount_set(&skb->users, 1); |
1da177e4 LT |
226 | skb->head = data; |
227 | skb->data = data; | |
27a884dc | 228 | skb_reset_tail_pointer(skb); |
4305b541 | 229 | skb->end = skb->tail + size; |
35d04610 CW |
230 | skb->mac_header = (typeof(skb->mac_header))~0U; |
231 | skb->transport_header = (typeof(skb->transport_header))~0U; | |
19633e12 | 232 | |
4947d3ef BL |
233 | /* make sure we initialize shinfo sequentially */ |
234 | shinfo = skb_shinfo(skb); | |
ec7d2f2c | 235 | memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); |
4947d3ef | 236 | atomic_set(&shinfo->dataref, 1); |
4947d3ef | 237 | |
c93bdd0e | 238 | if (flags & SKB_ALLOC_FCLONE) { |
d0bf4a9e | 239 | struct sk_buff_fclones *fclones; |
1da177e4 | 240 | |
d0bf4a9e ED |
241 | fclones = container_of(skb, struct sk_buff_fclones, skb1); |
242 | ||
d179cd12 | 243 | skb->fclone = SKB_FCLONE_ORIG; |
2638595a | 244 | refcount_set(&fclones->fclone_ref, 1); |
d179cd12 | 245 | |
6ffe75eb | 246 | fclones->skb2.fclone = SKB_FCLONE_CLONE; |
d179cd12 | 247 | } |
1da177e4 LT |
248 | out: |
249 | return skb; | |
250 | nodata: | |
8798b3fb | 251 | kmem_cache_free(cache, skb); |
1da177e4 LT |
252 | skb = NULL; |
253 | goto out; | |
1da177e4 | 254 | } |
b4ac530f | 255 | EXPORT_SYMBOL(__alloc_skb); |
1da177e4 | 256 | |
ba0509b6 JDB |
257 | /* Caller must provide SKB that is memset cleared */ |
258 | static struct sk_buff *__build_skb_around(struct sk_buff *skb, | |
259 | void *data, unsigned int frag_size) | |
260 | { | |
261 | struct skb_shared_info *shinfo; | |
262 | unsigned int size = frag_size ? : ksize(data); | |
263 | ||
264 | size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); | |
265 | ||
266 | /* Assumes caller memset cleared SKB */ | |
267 | skb->truesize = SKB_TRUESIZE(size); | |
268 | refcount_set(&skb->users, 1); | |
269 | skb->head = data; | |
270 | skb->data = data; | |
271 | skb_reset_tail_pointer(skb); | |
272 | skb->end = skb->tail + size; | |
273 | skb->mac_header = (typeof(skb->mac_header))~0U; | |
274 | skb->transport_header = (typeof(skb->transport_header))~0U; | |
275 | ||
276 | /* make sure we initialize shinfo sequentially */ | |
277 | shinfo = skb_shinfo(skb); | |
278 | memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); | |
279 | atomic_set(&shinfo->dataref, 1); | |
280 | ||
281 | return skb; | |
282 | } | |
283 | ||
b2b5ce9d | 284 | /** |
2ea2f62c | 285 | * __build_skb - build a network buffer |
b2b5ce9d | 286 | * @data: data buffer provided by caller |
2ea2f62c | 287 | * @frag_size: size of data, or 0 if head was kmalloced |
b2b5ce9d ED |
288 | * |
289 | * Allocate a new &sk_buff. Caller provides space holding head and | |
deceb4c0 | 290 | * skb_shared_info. @data must have been allocated by kmalloc() only if |
2ea2f62c ED |
291 | * @frag_size is 0, otherwise data should come from the page allocator |
292 | * or vmalloc() | |
b2b5ce9d ED |
293 | * 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 | */ | |
2ea2f62c | 303 | struct sk_buff *__build_skb(void *data, unsigned int frag_size) |
b2b5ce9d | 304 | { |
b2b5ce9d | 305 | struct sk_buff *skb; |
b2b5ce9d ED |
306 | |
307 | skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC); | |
ba0509b6 | 308 | if (unlikely(!skb)) |
b2b5ce9d ED |
309 | return NULL; |
310 | ||
b2b5ce9d | 311 | memset(skb, 0, offsetof(struct sk_buff, tail)); |
b2b5ce9d | 312 | |
ba0509b6 | 313 | return __build_skb_around(skb, data, frag_size); |
b2b5ce9d | 314 | } |
2ea2f62c ED |
315 | |
316 | /* build_skb() is wrapper over __build_skb(), that specifically | |
317 | * takes care of skb->head and skb->pfmemalloc | |
318 | * This means that if @frag_size is not zero, then @data must be backed | |
319 | * by a page fragment, not kmalloc() or vmalloc() | |
320 | */ | |
321 | struct sk_buff *build_skb(void *data, unsigned int frag_size) | |
322 | { | |
323 | struct sk_buff *skb = __build_skb(data, frag_size); | |
324 | ||
325 | if (skb && frag_size) { | |
326 | skb->head_frag = 1; | |
2f064f34 | 327 | if (page_is_pfmemalloc(virt_to_head_page(data))) |
2ea2f62c ED |
328 | skb->pfmemalloc = 1; |
329 | } | |
330 | return skb; | |
331 | } | |
b2b5ce9d ED |
332 | EXPORT_SYMBOL(build_skb); |
333 | ||
ba0509b6 JDB |
334 | /** |
335 | * build_skb_around - build a network buffer around provided skb | |
336 | * @skb: sk_buff provide by caller, must be memset cleared | |
337 | * @data: data buffer provided by caller | |
338 | * @frag_size: size of data, or 0 if head was kmalloced | |
339 | */ | |
340 | struct sk_buff *build_skb_around(struct sk_buff *skb, | |
341 | void *data, unsigned int frag_size) | |
342 | { | |
343 | if (unlikely(!skb)) | |
344 | return NULL; | |
345 | ||
346 | skb = __build_skb_around(skb, data, frag_size); | |
347 | ||
348 | if (skb && frag_size) { | |
349 | skb->head_frag = 1; | |
350 | if (page_is_pfmemalloc(virt_to_head_page(data))) | |
351 | skb->pfmemalloc = 1; | |
352 | } | |
353 | return skb; | |
354 | } | |
355 | EXPORT_SYMBOL(build_skb_around); | |
356 | ||
795bb1c0 JDB |
357 | #define NAPI_SKB_CACHE_SIZE 64 |
358 | ||
359 | struct napi_alloc_cache { | |
360 | struct page_frag_cache page; | |
e0d7924a | 361 | unsigned int skb_count; |
795bb1c0 JDB |
362 | void *skb_cache[NAPI_SKB_CACHE_SIZE]; |
363 | }; | |
364 | ||
b63ae8ca | 365 | static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache); |
795bb1c0 | 366 | static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache); |
ffde7328 AD |
367 | |
368 | static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) | |
369 | { | |
b63ae8ca | 370 | struct page_frag_cache *nc; |
ffde7328 AD |
371 | unsigned long flags; |
372 | void *data; | |
373 | ||
374 | local_irq_save(flags); | |
9451980a | 375 | nc = this_cpu_ptr(&netdev_alloc_cache); |
8c2dd3e4 | 376 | data = page_frag_alloc(nc, fragsz, gfp_mask); |
6f532612 ED |
377 | local_irq_restore(flags); |
378 | return data; | |
379 | } | |
c93bdd0e MG |
380 | |
381 | /** | |
382 | * netdev_alloc_frag - allocate a page fragment | |
383 | * @fragsz: fragment size | |
384 | * | |
385 | * Allocates a frag from a page for receive buffer. | |
386 | * Uses GFP_ATOMIC allocations. | |
387 | */ | |
388 | void *netdev_alloc_frag(unsigned int fragsz) | |
389 | { | |
3bed3cc4 AD |
390 | fragsz = SKB_DATA_ALIGN(fragsz); |
391 | ||
453f85d4 | 392 | return __netdev_alloc_frag(fragsz, GFP_ATOMIC); |
c93bdd0e | 393 | } |
6f532612 ED |
394 | EXPORT_SYMBOL(netdev_alloc_frag); |
395 | ||
ffde7328 AD |
396 | static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) |
397 | { | |
795bb1c0 | 398 | struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); |
9451980a | 399 | |
8c2dd3e4 | 400 | return page_frag_alloc(&nc->page, fragsz, gfp_mask); |
ffde7328 AD |
401 | } |
402 | ||
403 | void *napi_alloc_frag(unsigned int fragsz) | |
404 | { | |
3bed3cc4 AD |
405 | fragsz = SKB_DATA_ALIGN(fragsz); |
406 | ||
453f85d4 | 407 | return __napi_alloc_frag(fragsz, GFP_ATOMIC); |
ffde7328 AD |
408 | } |
409 | EXPORT_SYMBOL(napi_alloc_frag); | |
410 | ||
fd11a83d AD |
411 | /** |
412 | * __netdev_alloc_skb - allocate an skbuff for rx on a specific device | |
413 | * @dev: network device to receive on | |
d7499160 | 414 | * @len: length to allocate |
fd11a83d AD |
415 | * @gfp_mask: get_free_pages mask, passed to alloc_skb |
416 | * | |
417 | * Allocate a new &sk_buff and assign it a usage count of one. The | |
418 | * buffer has NET_SKB_PAD headroom built in. Users should allocate | |
419 | * the headroom they think they need without accounting for the | |
420 | * built in space. The built in space is used for optimisations. | |
421 | * | |
422 | * %NULL is returned if there is no free memory. | |
423 | */ | |
9451980a AD |
424 | struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len, |
425 | gfp_t gfp_mask) | |
fd11a83d | 426 | { |
b63ae8ca | 427 | struct page_frag_cache *nc; |
9451980a | 428 | unsigned long flags; |
fd11a83d | 429 | struct sk_buff *skb; |
9451980a AD |
430 | bool pfmemalloc; |
431 | void *data; | |
432 | ||
433 | len += NET_SKB_PAD; | |
fd11a83d | 434 | |
9451980a | 435 | if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) || |
d0164adc | 436 | (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) { |
a080e7bd AD |
437 | skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE); |
438 | if (!skb) | |
439 | goto skb_fail; | |
440 | goto skb_success; | |
441 | } | |
fd11a83d | 442 | |
9451980a AD |
443 | len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
444 | len = SKB_DATA_ALIGN(len); | |
445 | ||
446 | if (sk_memalloc_socks()) | |
447 | gfp_mask |= __GFP_MEMALLOC; | |
448 | ||
449 | local_irq_save(flags); | |
450 | ||
451 | nc = this_cpu_ptr(&netdev_alloc_cache); | |
8c2dd3e4 | 452 | data = page_frag_alloc(nc, len, gfp_mask); |
9451980a AD |
453 | pfmemalloc = nc->pfmemalloc; |
454 | ||
455 | local_irq_restore(flags); | |
456 | ||
457 | if (unlikely(!data)) | |
458 | return NULL; | |
459 | ||
460 | skb = __build_skb(data, len); | |
461 | if (unlikely(!skb)) { | |
181edb2b | 462 | skb_free_frag(data); |
9451980a | 463 | return NULL; |
7b2e497a | 464 | } |
fd11a83d | 465 | |
9451980a AD |
466 | /* use OR instead of assignment to avoid clearing of bits in mask */ |
467 | if (pfmemalloc) | |
468 | skb->pfmemalloc = 1; | |
469 | skb->head_frag = 1; | |
470 | ||
a080e7bd | 471 | skb_success: |
9451980a AD |
472 | skb_reserve(skb, NET_SKB_PAD); |
473 | skb->dev = dev; | |
474 | ||
a080e7bd | 475 | skb_fail: |
8af27456 CH |
476 | return skb; |
477 | } | |
b4ac530f | 478 | EXPORT_SYMBOL(__netdev_alloc_skb); |
1da177e4 | 479 | |
fd11a83d AD |
480 | /** |
481 | * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance | |
482 | * @napi: napi instance this buffer was allocated for | |
d7499160 | 483 | * @len: length to allocate |
fd11a83d AD |
484 | * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages |
485 | * | |
486 | * Allocate a new sk_buff for use in NAPI receive. This buffer will | |
487 | * attempt to allocate the head from a special reserved region used | |
488 | * only for NAPI Rx allocation. By doing this we can save several | |
489 | * CPU cycles by avoiding having to disable and re-enable IRQs. | |
490 | * | |
491 | * %NULL is returned if there is no free memory. | |
492 | */ | |
9451980a AD |
493 | struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, |
494 | gfp_t gfp_mask) | |
fd11a83d | 495 | { |
795bb1c0 | 496 | struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); |
fd11a83d | 497 | struct sk_buff *skb; |
9451980a AD |
498 | void *data; |
499 | ||
500 | len += NET_SKB_PAD + NET_IP_ALIGN; | |
fd11a83d | 501 | |
9451980a | 502 | if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) || |
d0164adc | 503 | (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) { |
a080e7bd AD |
504 | skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE); |
505 | if (!skb) | |
506 | goto skb_fail; | |
507 | goto skb_success; | |
508 | } | |
9451980a AD |
509 | |
510 | len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); | |
511 | len = SKB_DATA_ALIGN(len); | |
512 | ||
513 | if (sk_memalloc_socks()) | |
514 | gfp_mask |= __GFP_MEMALLOC; | |
fd11a83d | 515 | |
8c2dd3e4 | 516 | data = page_frag_alloc(&nc->page, len, gfp_mask); |
9451980a AD |
517 | if (unlikely(!data)) |
518 | return NULL; | |
519 | ||
520 | skb = __build_skb(data, len); | |
521 | if (unlikely(!skb)) { | |
181edb2b | 522 | skb_free_frag(data); |
9451980a | 523 | return NULL; |
fd11a83d AD |
524 | } |
525 | ||
9451980a | 526 | /* use OR instead of assignment to avoid clearing of bits in mask */ |
795bb1c0 | 527 | if (nc->page.pfmemalloc) |
9451980a AD |
528 | skb->pfmemalloc = 1; |
529 | skb->head_frag = 1; | |
530 | ||
a080e7bd | 531 | skb_success: |
9451980a AD |
532 | skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); |
533 | skb->dev = napi->dev; | |
534 | ||
a080e7bd | 535 | skb_fail: |
fd11a83d AD |
536 | return skb; |
537 | } | |
538 | EXPORT_SYMBOL(__napi_alloc_skb); | |
539 | ||
654bed16 | 540 | void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, |
50269e19 | 541 | int size, unsigned int truesize) |
654bed16 PZ |
542 | { |
543 | skb_fill_page_desc(skb, i, page, off, size); | |
544 | skb->len += size; | |
545 | skb->data_len += size; | |
50269e19 | 546 | skb->truesize += truesize; |
654bed16 PZ |
547 | } |
548 | EXPORT_SYMBOL(skb_add_rx_frag); | |
549 | ||
f8e617e1 JW |
550 | void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size, |
551 | unsigned int truesize) | |
552 | { | |
553 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; | |
554 | ||
555 | skb_frag_size_add(frag, size); | |
556 | skb->len += size; | |
557 | skb->data_len += size; | |
558 | skb->truesize += truesize; | |
559 | } | |
560 | EXPORT_SYMBOL(skb_coalesce_rx_frag); | |
561 | ||
27b437c8 | 562 | static void skb_drop_list(struct sk_buff **listp) |
1da177e4 | 563 | { |
bd8a7036 | 564 | kfree_skb_list(*listp); |
27b437c8 | 565 | *listp = NULL; |
1da177e4 LT |
566 | } |
567 | ||
27b437c8 HX |
568 | static inline void skb_drop_fraglist(struct sk_buff *skb) |
569 | { | |
570 | skb_drop_list(&skb_shinfo(skb)->frag_list); | |
571 | } | |
572 | ||
1da177e4 LT |
573 | static void skb_clone_fraglist(struct sk_buff *skb) |
574 | { | |
575 | struct sk_buff *list; | |
576 | ||
fbb398a8 | 577 | skb_walk_frags(skb, list) |
1da177e4 LT |
578 | skb_get(list); |
579 | } | |
580 | ||
d3836f21 ED |
581 | static void skb_free_head(struct sk_buff *skb) |
582 | { | |
181edb2b AD |
583 | unsigned char *head = skb->head; |
584 | ||
d3836f21 | 585 | if (skb->head_frag) |
181edb2b | 586 | skb_free_frag(head); |
d3836f21 | 587 | else |
181edb2b | 588 | kfree(head); |
d3836f21 ED |
589 | } |
590 | ||
5bba1712 | 591 | static void skb_release_data(struct sk_buff *skb) |
1da177e4 | 592 | { |
ff04a771 ED |
593 | struct skb_shared_info *shinfo = skb_shinfo(skb); |
594 | int i; | |
1da177e4 | 595 | |
ff04a771 ED |
596 | if (skb->cloned && |
597 | atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, | |
598 | &shinfo->dataref)) | |
599 | return; | |
a6686f2f | 600 | |
ff04a771 ED |
601 | for (i = 0; i < shinfo->nr_frags; i++) |
602 | __skb_frag_unref(&shinfo->frags[i]); | |
a6686f2f | 603 | |
ff04a771 ED |
604 | if (shinfo->frag_list) |
605 | kfree_skb_list(shinfo->frag_list); | |
606 | ||
1f8b977a | 607 | skb_zcopy_clear(skb, true); |
ff04a771 | 608 | skb_free_head(skb); |
1da177e4 LT |
609 | } |
610 | ||
611 | /* | |
612 | * Free an skbuff by memory without cleaning the state. | |
613 | */ | |
2d4baff8 | 614 | static void kfree_skbmem(struct sk_buff *skb) |
1da177e4 | 615 | { |
d0bf4a9e | 616 | struct sk_buff_fclones *fclones; |
d179cd12 | 617 | |
d179cd12 DM |
618 | switch (skb->fclone) { |
619 | case SKB_FCLONE_UNAVAILABLE: | |
620 | kmem_cache_free(skbuff_head_cache, skb); | |
6ffe75eb | 621 | return; |
d179cd12 DM |
622 | |
623 | case SKB_FCLONE_ORIG: | |
d0bf4a9e | 624 | fclones = container_of(skb, struct sk_buff_fclones, skb1); |
d179cd12 | 625 | |
6ffe75eb ED |
626 | /* We usually free the clone (TX completion) before original skb |
627 | * This test would have no chance to be true for the clone, | |
628 | * while here, branch prediction will be good. | |
d179cd12 | 629 | */ |
2638595a | 630 | if (refcount_read(&fclones->fclone_ref) == 1) |
6ffe75eb ED |
631 | goto fastpath; |
632 | break; | |
e7820e39 | 633 | |
6ffe75eb ED |
634 | default: /* SKB_FCLONE_CLONE */ |
635 | fclones = container_of(skb, struct sk_buff_fclones, skb2); | |
d179cd12 | 636 | break; |
3ff50b79 | 637 | } |
2638595a | 638 | if (!refcount_dec_and_test(&fclones->fclone_ref)) |
6ffe75eb ED |
639 | return; |
640 | fastpath: | |
641 | kmem_cache_free(skbuff_fclone_cache, fclones); | |
1da177e4 LT |
642 | } |
643 | ||
0a463c78 | 644 | void skb_release_head_state(struct sk_buff *skb) |
1da177e4 | 645 | { |
adf30907 | 646 | skb_dst_drop(skb); |
9c2b3328 SH |
647 | if (skb->destructor) { |
648 | WARN_ON(in_irq()); | |
1da177e4 LT |
649 | skb->destructor(skb); |
650 | } | |
a3bf7ae9 | 651 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
cb9c6836 | 652 | nf_conntrack_put(skb_nfct(skb)); |
1da177e4 | 653 | #endif |
df5042f4 | 654 | skb_ext_put(skb); |
04a4bb55 LB |
655 | } |
656 | ||
657 | /* Free everything but the sk_buff shell. */ | |
658 | static void skb_release_all(struct sk_buff *skb) | |
659 | { | |
660 | skb_release_head_state(skb); | |
a28b1b90 FW |
661 | if (likely(skb->head)) |
662 | skb_release_data(skb); | |
2d4baff8 HX |
663 | } |
664 | ||
665 | /** | |
666 | * __kfree_skb - private function | |
667 | * @skb: buffer | |
668 | * | |
669 | * Free an sk_buff. Release anything attached to the buffer. | |
670 | * Clean the state. This is an internal helper function. Users should | |
671 | * always call kfree_skb | |
672 | */ | |
1da177e4 | 673 | |
2d4baff8 HX |
674 | void __kfree_skb(struct sk_buff *skb) |
675 | { | |
676 | skb_release_all(skb); | |
1da177e4 LT |
677 | kfree_skbmem(skb); |
678 | } | |
b4ac530f | 679 | EXPORT_SYMBOL(__kfree_skb); |
1da177e4 | 680 | |