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1 | /* |
2 | * Routines having to do with the 'struct sk_buff' memory handlers. |
3 | * |
4 | * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> |
5 | * Florian La Roche <rzsfl@rz.uni-sb.de> |
6 | * |
7 | * 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 | |
39 | #include <linux/module.h> |
40 | #include <linux/types.h> |
41 | #include <linux/kernel.h> |
42 | #include <linux/kmemcheck.h> |
43 | #include <linux/mm.h> |
44 | #include <linux/interrupt.h> |
45 | #include <linux/in.h> |
46 | #include <linux/inet.h> |
47 | #include <linux/slab.h> |
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> |
54 | #include <linux/splice.h> |
55 | #include <linux/cache.h> |
56 | #include <linux/rtnetlink.h> |
57 | #include <linux/init.h> |
58 | #include <linux/scatterlist.h> |
59 | #include <linux/errqueue.h> |
60 | |
61 | #include <net/protocol.h> |
62 | #include <net/dst.h> |
63 | #include <net/sock.h> |
64 | #include <net/checksum.h> |
65 | #include <net/xfrm.h> |
66 | |
67 | #include <asm/uaccess.h> |
68 | #include <asm/system.h> |
69 | #include <trace/events/skb.h> |
70 | |
71 | #include "kmap_skb.h" |
72 | |
73 | static struct kmem_cache *skbuff_head_cache __read_mostly; |
74 | static struct kmem_cache *skbuff_fclone_cache __read_mostly; |
75 | |
76 | static void sock_pipe_buf_release(struct pipe_inode_info *pipe, |
77 | struct pipe_buffer *buf) |
78 | { |
79 | put_page(buf->page); |
80 | } |
81 | |
82 | static void sock_pipe_buf_get(struct pipe_inode_info *pipe, |
83 | struct pipe_buffer *buf) |
84 | { |
85 | get_page(buf->page); |
86 | } |
87 | |
88 | static int sock_pipe_buf_steal(struct pipe_inode_info *pipe, |
89 | struct pipe_buffer *buf) |
90 | { |
91 | return 1; |
92 | } |
93 | |
94 | |
95 | /* Pipe buffer operations for a socket. */ |
96 | static const struct pipe_buf_operations sock_pipe_buf_ops = { |
97 | .can_merge = 0, |
98 | .map = generic_pipe_buf_map, |
99 | .unmap = generic_pipe_buf_unmap, |
100 | .confirm = generic_pipe_buf_confirm, |
101 | .release = sock_pipe_buf_release, |
102 | .steal = sock_pipe_buf_steal, |
103 | .get = sock_pipe_buf_get, |
104 | }; |
105 | |
106 | /* |
107 | * Keep out-of-line to prevent kernel bloat. |
108 | * __builtin_return_address is not used because it is not always |
109 | * reliable. |
110 | */ |
111 | |
112 | /** |
113 | * skb_over_panic - private function |
114 | * @skb: buffer |
115 | * @sz: size |
116 | * @here: address |
117 | * |
118 | * Out of line support code for skb_put(). Not user callable. |
119 | */ |
120 | void skb_over_panic(struct sk_buff *skb, int sz, void *here) |
121 | { |
122 | printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " |
123 | "data:%p tail:%#lx end:%#lx dev:%s\n", |
124 | here, skb->len, sz, skb->head, skb->data, |
125 | (unsigned long)skb->tail, (unsigned long)skb->end, |
126 | skb->dev ? skb->dev->name : "<NULL>"); |
127 | BUG(); |
128 | } |
129 | EXPORT_SYMBOL(skb_over_panic); |
130 | |
131 | /** |
132 | * skb_under_panic - private function |
133 | * @skb: buffer |
134 | * @sz: size |
135 | * @here: address |
136 | * |
137 | * Out of line support code for skb_push(). Not user callable. |
138 | */ |
139 | |
140 | void skb_under_panic(struct sk_buff *skb, int sz, void *here) |
141 | { |
142 | printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " |
143 | "data:%p tail:%#lx end:%#lx dev:%s\n", |
144 | here, skb->len, sz, skb->head, skb->data, |
145 | (unsigned long)skb->tail, (unsigned long)skb->end, |
146 | skb->dev ? skb->dev->name : "<NULL>"); |
147 | BUG(); |
148 | } |
149 | EXPORT_SYMBOL(skb_under_panic); |
150 | |
151 | /* Allocate a new skbuff. We do this ourselves so we can fill in a few |
152 | * 'private' fields and also do memory statistics to find all the |
153 | * [BEEP] leaks. |
154 | * |
155 | */ |
156 | |
157 | /** |
158 | * __alloc_skb - allocate a network buffer |
159 | * @size: size to allocate |
160 | * @gfp_mask: allocation mask |
161 | * @fclone: allocate from fclone cache instead of head cache |
162 | * and allocate a cloned (child) skb |
163 | * @node: numa node to allocate memory on |
164 | * |
165 | * Allocate a new &sk_buff. The returned buffer has no headroom and a |
166 | * tail room of size bytes. The object has a reference count of one. |
167 | * The return is the buffer. On a failure the return is %NULL. |
168 | * |
169 | * Buffers may only be allocated from interrupts using a @gfp_mask of |
170 | * %GFP_ATOMIC. |
171 | */ |
172 | struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, |
173 | int fclone, int node) |
174 | { |
175 | struct kmem_cache *cache; |
176 | struct skb_shared_info *shinfo; |
177 | struct sk_buff *skb; |
178 | u8 *data; |
179 | |
180 | cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; |
181 | |
182 | /* Get the HEAD */ |
183 | skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node); |
184 | if (!skb) |
185 | goto out; |
186 | |
187 | size = SKB_DATA_ALIGN(size); |
188 | data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info), |
189 | gfp_mask, node); |
190 | if (!data) |
191 | goto nodata; |
192 | |
193 | /* |
194 | * Only clear those fields we need to clear, not those that we will |
195 | * actually initialise below. Hence, don't put any more fields after |
196 | * the tail pointer in struct sk_buff! |
197 | */ |
198 | memset(skb, 0, offsetof(struct sk_buff, tail)); |
199 | skb->truesize = size + sizeof(struct sk_buff); |
200 | atomic_set(&skb->users, 1); |
201 | skb->head = data; |
202 | skb->data = data; |
203 | skb_reset_tail_pointer(skb); |
204 | skb->end = skb->tail + size; |
205 | kmemcheck_annotate_bitfield(skb, flags1); |
206 | kmemcheck_annotate_bitfield(skb, flags2); |
207 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
208 | skb->mac_header = ~0U; |
209 | #endif |
210 | |
211 | /* make sure we initialize shinfo sequentially */ |
212 | shinfo = skb_shinfo(skb); |
213 | atomic_set(&shinfo->dataref, 1); |
214 | shinfo->nr_frags = 0; |
215 | shinfo->gso_size = 0; |
216 | shinfo->gso_segs = 0; |
217 | shinfo->gso_type = 0; |
218 | shinfo->ip6_frag_id = 0; |
219 | shinfo->tx_flags.flags = 0; |
220 | skb_frag_list_init(skb); |
221 | memset(&shinfo->hwtstamps, 0, sizeof(shinfo->hwtstamps)); |
222 | |
223 | if (fclone) { |
224 | struct sk_buff *child = skb + 1; |
225 | atomic_t *fclone_ref = (atomic_t *) (child + 1); |
226 | |
227 | kmemcheck_annotate_bitfield(child, flags1); |
228 | kmemcheck_annotate_bitfield(child, flags2); |
229 | skb->fclone = SKB_FCLONE_ORIG; |
230 | atomic_set(fclone_ref, 1); |
231 | |
232 | child->fclone = SKB_FCLONE_UNAVAILABLE; |
233 | } |
234 | out: |
235 | return skb; |
236 | nodata: |
237 | kmem_cache_free(cache, skb); |
238 | skb = NULL; |
239 | goto out; |
240 | } |
241 | EXPORT_SYMBOL(__alloc_skb); |
242 | |
243 | /** |
244 | * __netdev_alloc_skb - allocate an skbuff for rx on a specific device |
245 | * @dev: network device to receive on |
246 | * @length: length to allocate |
247 | * @gfp_mask: get_free_pages mask, passed to alloc_skb |
248 | * |
249 | * Allocate a new &sk_buff and assign it a usage count of one. The |
250 | * buffer has unspecified headroom built in. Users should allocate |
251 | * the headroom they think they need without accounting for the |
252 | * built in space. The built in space is used for optimisations. |
253 | * |
254 | * %NULL is returned if there is no free memory. |
255 | */ |
256 | struct sk_buff *__netdev_alloc_skb(struct net_device *dev, |
257 | unsigned int length, gfp_t gfp_mask) |
258 | { |
259 | int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1; |
260 | struct sk_buff *skb; |
261 | |
262 | skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node); |
263 | if (likely(skb)) { |
264 | skb_reserve(skb, NET_SKB_PAD); |
265 | skb->dev = dev; |
266 | } |
267 | return skb; |
268 | } |
269 | EXPORT_SYMBOL(__netdev_alloc_skb); |
270 | |
271 | struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask) |
272 | { |
273 | int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1; |
274 | struct page *page; |
275 | |
276 | page = alloc_pages_node(node, gfp_mask, 0); |
277 | return page; |
278 | } |
279 | EXPORT_SYMBOL(__netdev_alloc_page); |
280 | |
281 | void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, |
282 | int size) |
283 | { |
284 | skb_fill_page_desc(skb, i, page, off, size); |
285 | skb->len += size; |
286 | skb->data_len += size; |
287 | skb->truesize += size; |
288 | } |
289 | EXPORT_SYMBOL(skb_add_rx_frag); |
290 | |
291 | /** |
292 | * dev_alloc_skb - allocate an skbuff for receiving |
293 | * @length: length to allocate |
294 | * |
295 | * Allocate a new &sk_buff and assign it a usage count of one. The |
296 | * buffer has unspecified headroom built in. Users should allocate |
297 | * the headroom they think they need without accounting for the |
298 | * built in space. The built in space is used for optimisations. |
299 | * |
300 | * %NULL is returned if there is no free memory. Although this function |
301 | * allocates memory it can be called from an interrupt. |
302 | */ |
303 | struct sk_buff *dev_alloc_skb(unsigned int length) |
304 | { |
305 | /* |
306 | * There is more code here than it seems: |
307 | * __dev_alloc_skb is an inline |
308 | */ |
309 | return __dev_alloc_skb(length, GFP_ATOMIC); |
310 | } |
311 | EXPORT_SYMBOL(dev_alloc_skb); |
312 | |
313 | static void skb_drop_list(struct sk_buff **listp) |
314 | { |
315 | struct sk_buff *list = *listp; |
316 | |
317 | *listp = NULL; |
318 | |
319 | do { |
320 | struct sk_buff *this = list; |
321 | list = list->next; |
322 | kfree_skb(this); |
323 | } while (list); |
324 | } |
325 | |
326 | static inline void skb_drop_fraglist(struct sk_buff *skb) |
327 | { |
328 | skb_drop_list(&skb_shinfo(skb)->frag_list); |
329 | } |
330 | |
331 | static void skb_clone_fraglist(struct sk_buff *skb) |
332 | { |
333 | struct sk_buff *list; |
334 | |
335 | skb_walk_frags(skb, list) |
336 | skb_get(list); |
337 | } |
338 | |
339 | static void skb_release_data(struct sk_buff *skb) |
340 | { |
341 | if (!skb->cloned || |
342 | !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, |
343 | &skb_shinfo(skb)->dataref)) { |
344 | if (skb_shinfo(skb)->nr_frags) { |
345 | int i; |
346 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
347 | put_page(skb_shinfo(skb)->frags[i].page); |
348 | } |
349 | |
350 | if (skb_has_frags(skb)) |
351 | skb_drop_fraglist(skb); |
352 | |
353 | kfree(skb->head); |
354 | } |
355 | } |
356 | |
357 | /* |
358 | * Free an skbuff by memory without cleaning the state. |
359 | */ |
360 | static void kfree_skbmem(struct sk_buff *skb) |
361 | { |
362 | struct sk_buff *other; |
363 | atomic_t *fclone_ref; |
364 | |
365 | switch (skb->fclone) { |
366 | case SKB_FCLONE_UNAVAILABLE: |
367 | kmem_cache_free(skbuff_head_cache, skb); |
368 | break; |
369 | |
370 | case SKB_FCLONE_ORIG: |
371 | fclone_ref = (atomic_t *) (skb + 2); |
372 | if (atomic_dec_and_test(fclone_ref)) |
373 | kmem_cache_free(skbuff_fclone_cache, skb); |
374 | break; |
375 | |
376 | case SKB_FCLONE_CLONE: |
377 | fclone_ref = (atomic_t *) (skb + 1); |
378 | other = skb - 1; |
379 | |
380 | /* The clone portion is available for |
381 | * fast-cloning again. |
382 | */ |
383 | skb->fclone = SKB_FCLONE_UNAVAILABLE; |
384 | |
385 | if (atomic_dec_and_test(fclone_ref)) |
386 | kmem_cache_free(skbuff_fclone_cache, other); |
387 | break; |
388 | } |
389 | } |
390 | |
391 | static void skb_release_head_state(struct sk_buff *skb) |
392 | { |
393 | skb_dst_drop(skb); |
394 | #ifdef CONFIG_XFRM |
395 | secpath_put(skb->sp); |
396 | #endif |
397 | if (skb->destructor) { |
398 | WARN_ON(in_irq()); |
399 | skb->destructor(skb); |
400 | } |
401 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
402 | nf_conntrack_put(skb->nfct); |
403 | nf_conntrack_put_reasm(skb->nfct_reasm); |
404 | #endif |
405 | #ifdef CONFIG_BRIDGE_NETFILTER |
406 | nf_bridge_put(skb->nf_bridge); |
407 | #endif |
408 | /* XXX: IS this still necessary? - JHS */ |
409 | #ifdef CONFIG_NET_SCHED |
410 | skb->tc_index = 0; |
411 | #ifdef CONFIG_NET_CLS_ACT |
412 | skb->tc_verd = 0; |
413 | #endif |
414 | #endif |
415 | } |
416 | |
417 | /* Free everything but the sk_buff shell. */ |
418 | static void skb_release_all(struct sk_buff *skb) |
419 | { |
420 | skb_release_head_state(skb); |
421 | skb_release_data(skb); |
422 | } |
423 | |
424 | /** |
425 | * __kfree_skb - private function |
426 | * @skb: buffer |
427 | * |
428 | * Free an sk_buff. Release anything attached to the buffer. |
429 | * Clean the state. This is an internal helper function. Users should |
430 | * always call kfree_skb |
431 | */ |
432 | |
433 | void __kfree_skb(struct sk_buff *skb) |
434 | { |
435 | skb_release_all(skb); |
436 | kfree_skbmem(skb); |
437 | } |
438 | EXPORT_SYMBOL(__kfree_skb); |
439 | |
440 | /** |
441 | * kfree_skb - free an sk_buff |
442 | * @skb: buffer to free |
443 | * |
444 | * Drop a reference to the buffer and free it if the usage count has |
445 | * hit zero. |
446 | */ |
447 | void kfree_skb(struct sk_buff *skb) |
448 | { |
449 | if (unlikely(!skb)) |
450 | return; |
451 | if (likely(atomic_read(&skb->users) == 1)) |
452 | smp_rmb(); |
453 | else if (likely(!atomic_dec_and_test(&skb->users))) |
454 | return; |
455 | trace_kfree_skb(skb, __builtin_return_address(0)); |
456 | __kfree_skb(skb); |
457 | } |
458 | EXPORT_SYMBOL(kfree_skb); |
459 | |
460 | /** |
461 | * consume_skb - free an skbuff |
462 | * @skb: buffer to free |
463 | * |
464 | * Drop a ref to the buffer and free it if the usage count has hit zero |
465 | * Functions identically to kfree_skb, but kfree_skb assumes that the frame |
466 | * is being dropped after a failure and notes that |
467 | */ |
468 | void consume_skb(struct sk_buff *skb) |
469 | { |
470 | if (unlikely(!skb)) |
471 | return; |
472 | if (likely(atomic_read(&skb->users) == 1)) |
473 | smp_rmb(); |
474 | else if (likely(!atomic_dec_and_test(&skb->users))) |
475 | return; |
476 | __kfree_skb(skb); |
477 | } |
478 | EXPORT_SYMBOL(consume_skb); |
479 | |
480 | /** |
481 | * skb_recycle_check - check if skb can be reused for receive |
482 | * @skb: buffer |
483 | * @skb_size: minimum receive buffer size |
484 | * |
485 | * Checks that the skb passed in is not shared or cloned, and |
486 | * that it is linear and its head portion at least as large as |
487 | * skb_size so that it can be recycled as a receive buffer. |
488 | * If these conditions are met, this function does any necessary |
489 | * reference count dropping and cleans up the skbuff as if it |
490 | * just came from __alloc_skb(). |
491 | */ |
492 | int skb_recycle_check(struct sk_buff *skb, int skb_size) |
493 | { |
494 | struct skb_shared_info *shinfo; |
495 | |
496 | if (irqs_disabled()) |
497 | return 0; |
498 | |
499 | if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE) |
500 | return 0; |
501 | |
502 | skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD); |
503 | if (skb_end_pointer(skb) - skb->head < skb_size) |
504 | return 0; |
505 | |
506 | if (skb_shared(skb) || skb_cloned(skb)) |
507 | return 0; |
508 | |
509 | skb_release_head_state(skb); |
510 | shinfo = skb_shinfo(skb); |
511 | atomic_set(&shinfo->dataref, 1); |
512 | shinfo->nr_frags = 0; |
513 | shinfo->gso_size = 0; |
514 | shinfo->gso_segs = 0; |
515 | shinfo->gso_type = 0; |
516 | shinfo->ip6_frag_id = 0; |
517 | shinfo->tx_flags.flags = 0; |
518 | skb_frag_list_init(skb); |
519 | memset(&shinfo->hwtstamps, 0, sizeof(shinfo->hwtstamps)); |
520 | |
521 | memset(skb, 0, offsetof(struct sk_buff, tail)); |
522 | skb->data = skb->head + NET_SKB_PAD; |
523 | skb_reset_tail_pointer(skb); |
524 | |
525 | return 1; |
526 | } |
527 | EXPORT_SYMBOL(skb_recycle_check); |
528 | |
529 | static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) |
530 | { |
531 | new->tstamp = old->tstamp; |
532 | new->dev = old->dev; |
533 | new->transport_header = old->transport_header; |
534 | new->network_header = old->network_header; |
535 | new->mac_header = old->mac_header; |
536 | skb_dst_set(new, dst_clone(skb_dst(old))); |
537 | #ifdef CONFIG_XFRM |
538 | new->sp = secpath_get(old->sp); |
539 | #endif |
540 | memcpy(new->cb, old->cb, sizeof(old->cb)); |
541 | new->csum = old->csum; |
542 | new->local_df = old->local_df; |
543 | new->pkt_type = old->pkt_type; |
544 | new->ip_summed = old->ip_summed; |
545 | skb_copy_queue_mapping(new, old); |
546 | new->priority = old->priority; |
547 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) |
548 | new->ipvs_property = old->ipvs_property; |
549 | #endif |
550 | new->protocol = old->protocol; |
551 | new->mark = old->mark; |
552 | new->skb_iif = old->skb_iif; |
553 | __nf_copy(new, old); |
554 | #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ |
555 | defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) |
556 | new->nf_trace = old->nf_trace; |
557 | #endif |
558 | #ifdef CONFIG_NET_SCHED |
559 | new->tc_index = old->tc_index; |
560 | #ifdef CONFIG_NET_CLS_ACT |
561 | new->tc_verd = old->tc_verd; |
562 | #endif |
563 | #endif |
564 | new->vlan_tci = old->vlan_tci; |
565 | |
566 | skb_copy_secmark(new, old); |
567 | } |
568 | |
569 | /* |
570 | * You should not add any new code to this function. Add it to |
571 | * __copy_skb_header above instead. |
572 | */ |
573 | static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) |
574 | { |
575 | #define C(x) n->x = skb->x |
576 | |
577 | n->next = n->prev = NULL; |
578 | n->sk = NULL; |
579 | __copy_skb_header(n, skb); |
580 | |
581 | C(len); |
582 | C(data_len); |
583 | C(mac_len); |
584 | n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len; |
585 | n->cloned = 1; |
586 | n->nohdr = 0; |
587 | n->destructor = NULL; |
588 | C(tail); |
589 | C(end); |
590 | C(head); |
591 | C(data); |
592 | C(truesize); |
593 | atomic_set(&n->users, 1); |
594 | |
595 | atomic_inc(&(skb_shinfo(skb)->dataref)); |
596 | skb->cloned = 1; |
597 | |
598 | return n; |
599 | #undef C |
600 | } |
601 | |
602 | /** |
603 | * skb_morph - morph one skb into another |
604 | * @dst: the skb to receive the contents |
605 | * @src: the skb to supply the contents |
606 | * |
607 | * This is identical to skb_clone except that the target skb is |
608 | * supplied by the user. |
609 | * |
610 | * The target skb is returned upon exit. |
611 | */ |
612 | struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src) |
613 | { |
614 | skb_release_all(dst); |
615 | return __skb_clone(dst, src); |
616 | } |
617 | EXPORT_SYMBOL_GPL(skb_morph); |
618 | |
619 | /** |
620 | * skb_clone - duplicate an sk_buff |
621 | * @skb: buffer to clone |
622 | * @gfp_mask: allocation priority |
623 | * |
624 | * Duplicate an &sk_buff. The new one is not owned by a socket. Both |
625 | * copies share the same packet data but not structure. The new |
626 | * buffer has a reference count of 1. If the allocation fails the |
627 | * function returns %NULL otherwise the new buffer is returned. |
628 | * |
629 | * If this function is called from an interrupt gfp_mask() must be |
630 | * %GFP_ATOMIC. |
631 | */ |
632 | |
633 | struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) |
634 | { |
635 | struct sk_buff *n; |
636 | |
637 | n = skb + 1; |
638 | if (skb->fclone == SKB_FCLONE_ORIG && |
639 | n->fclone == SKB_FCLONE_UNAVAILABLE) { |
640 | atomic_t *fclone_ref = (atomic_t *) (n + 1); |
641 | n->fclone = SKB_FCLONE_CLONE; |
642 | atomic_inc(fclone_ref); |
643 | } else { |
644 | n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); |
645 | if (!n) |
646 | return NULL; |
647 | |
648 | kmemcheck_annotate_bitfield(n, flags1); |
649 | kmemcheck_annotate_bitfield(n, flags2); |
650 | n->fclone = SKB_FCLONE_UNAVAILABLE; |
651 | } |
652 | |
653 | return __skb_clone(n, skb); |
654 | } |
655 | EXPORT_SYMBOL(skb_clone); |
656 | |
657 | static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) |
658 | { |
659 | #ifndef NET_SKBUFF_DATA_USES_OFFSET |
660 | /* |
661 | * Shift between the two data areas in bytes |
662 | */ |
663 | unsigned long offset = new->data - old->data; |
664 | #endif |
665 | |
666 | __copy_skb_header(new, old); |
667 | |
668 | #ifndef NET_SKBUFF_DATA_USES_OFFSET |
669 | /* {transport,network,mac}_header are relative to skb->head */ |
670 | new->transport_header += offset; |
671 | new->network_header += offset; |
672 | if (skb_mac_header_was_set(new)) |
673 | new->mac_header += offset; |
674 | #endif |
675 | skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; |
676 | skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; |
677 | skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; |
678 | } |
679 | |
680 | /** |
681 | * skb_copy - create private copy of an sk_buff |
682 | * @skb: buffer to copy |
683 | * @gfp_mask: allocation priority |
684 | * |
685 | * Make a copy of both an &sk_buff and its data. This is used when the |
686 | * caller wishes to modify the data and needs a private copy of the |
687 | * data to alter. Returns %NULL on failure or the pointer to the buffer |
688 | * on success. The returned buffer has a reference count of 1. |
689 | * |
690 | * As by-product this function converts non-linear &sk_buff to linear |
691 | * one, so that &sk_buff becomes completely private and caller is allowed |
692 | * to modify all the data of returned buffer. This means that this |
693 | * function is not recommended for use in circumstances when only |
694 | * header is going to be modified. Use pskb_copy() instead. |
695 | */ |
696 | |
697 | struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) |
698 | { |
699 | int headerlen = skb->data - skb->head; |
700 | /* |
701 | * Allocate the copy buffer |
702 | */ |
703 | struct sk_buff *n; |
704 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
705 | n = alloc_skb(skb->end + skb->data_len, gfp_mask); |
706 | #else |
707 | n = alloc_skb(skb->end - skb->head + skb->data_len, gfp_mask); |
708 | #endif |
709 | if (!n) |
710 | return NULL; |
711 | |
712 | /* Set the data pointer */ |
713 | skb_reserve(n, headerlen); |
714 | /* Set the tail pointer and length */ |
715 | skb_put(n, skb->len); |
716 | |
717 | if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) |
718 | BUG(); |
719 | |
720 | copy_skb_header(n, skb); |
721 | return n; |
722 | } |
723 | EXPORT_SYMBOL(skb_copy); |
724 | |
725 | /** |
726 | * pskb_copy - create copy of an sk_buff with private head. |
727 | * @skb: buffer to copy |
728 | * @gfp_mask: allocation priority |
729 | * |
730 | * Make a copy of both an &sk_buff and part of its data, located |
731 | * in header. Fragmented data remain shared. This is used when |
732 | * the caller wishes to modify only header of &sk_buff and needs |
733 | * private copy of the header to alter. Returns %NULL on failure |
734 | * or the pointer to the buffer on success. |
735 | * The returned buffer has a reference count of 1. |
736 | */ |
737 | |
738 | struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask) |
739 | { |
740 | /* |
741 | * Allocate the copy buffer |
742 | */ |
743 | struct sk_buff *n; |
744 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
745 | n = alloc_skb(skb->end, gfp_mask); |
746 | #else |
747 | n = alloc_skb(skb->end - skb->head, gfp_mask); |
748 | #endif |
749 | if (!n) |
750 | goto out; |
751 | |
752 | /* Set the data pointer */ |
753 | skb_reserve(n, skb->data - skb->head); |
754 | /* Set the tail pointer and length */ |
755 | skb_put(n, skb_headlen(skb)); |
756 | /* Copy the bytes */ |
757 | skb_copy_from_linear_data(skb, n->data, n->len); |
758 | |
759 | n->truesize += skb->data_len; |
760 | n->data_len = skb->data_len; |
761 | n->len = skb->len; |
762 | |
763 | if (skb_shinfo(skb)->nr_frags) { |
764 | int i; |
765 | |
766 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
767 | skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; |
768 | get_page(skb_shinfo(n)->frags[i].page); |
769 | } |
770 | skb_shinfo(n)->nr_frags = i; |
771 | } |
772 | |
773 | if (skb_has_frags(skb)) { |
774 | skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; |
775 | skb_clone_fraglist(n); |
776 | } |
777 | |
778 | copy_skb_header(n, skb); |
779 | out: |
780 | return n; |
781 | } |
782 | EXPORT_SYMBOL(pskb_copy); |
783 | |
784 | /** |
785 | * pskb_expand_head - reallocate header of &sk_buff |
786 | * @skb: buffer to reallocate |
787 | * @nhead: room to add at head |
788 | * @ntail: room to add at tail |
789 | * @gfp_mask: allocation priority |
790 | * |
791 | * Expands (or creates identical copy, if &nhead and &ntail are zero) |
792 | * header of skb. &sk_buff itself is not changed. &sk_buff MUST have |
793 | * reference count of 1. Returns zero in the case of success or error, |
794 | * if expansion failed. In the last case, &sk_buff is not changed. |
795 | * |
796 | * All the pointers pointing into skb header may change and must be |
797 | * reloaded after call to this function. |
798 | */ |
799 | |
800 | int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, |
801 | gfp_t gfp_mask) |
802 | { |
803 | int i; |
804 | u8 *data; |
805 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
806 | int size = nhead + skb->end + ntail; |
807 | #else |
808 | int size = nhead + (skb->end - skb->head) + ntail; |
809 | #endif |
810 | long off; |
811 | |
812 | BUG_ON(nhead < 0); |
813 | |
814 | if (skb_shared(skb)) |
815 | BUG(); |
816 | |
817 | size = SKB_DATA_ALIGN(size); |
818 | |
819 | data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); |
820 | if (!data) |
821 | goto nodata; |
822 | |
823 | /* Copy only real data... and, alas, header. This should be |
824 | * optimized for the cases when header is void. */ |
825 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
826 | memcpy(data + nhead, skb->head, skb->tail); |
827 | #else |
828 | memcpy(data + nhead, skb->head, skb->tail - skb->head); |
829 | #endif |
830 | memcpy(data + size, skb_end_pointer(skb), |
831 | sizeof(struct skb_shared_info)); |
832 | |
833 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
834 | get_page(skb_shinfo(skb)->frags[i].page); |
835 | |
836 | if (skb_has_frags(skb)) |
837 | skb_clone_fraglist(skb); |
838 | |
839 | skb_release_data(skb); |
840 | |
841 | off = (data + nhead) - skb->head; |
842 | |
843 | skb->head = data; |
844 | skb->data += off; |
845 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
846 | skb->end = size; |
847 | off = nhead; |
848 | #else |
849 | skb->end = skb->head + size; |
850 | #endif |
851 | /* {transport,network,mac}_header and tail are relative to skb->head */ |
852 | skb->tail += off; |
853 | skb->transport_header += off; |
854 | skb->network_header += off; |
855 | if (skb_mac_header_was_set(skb)) |
856 | skb->mac_header += off; |
857 | skb->csum_start += nhead; |
858 | skb->cloned = 0; |
859 | skb->hdr_len = 0; |
860 | skb->nohdr = 0; |
861 | atomic_set(&skb_shinfo(skb)->dataref, 1); |
862 | return 0; |
863 | |
864 | nodata: |
865 | return -ENOMEM; |
866 | } |
867 | EXPORT_SYMBOL(pskb_expand_head); |
868 | |
869 | /* Make private copy of skb with writable head and some headroom */ |
870 | |
871 | struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) |
872 | { |
873 | struct sk_buff *skb2; |
874 | int delta = headroom - skb_headroom(skb); |
875 | |
876 | if (delta <= 0) |
877 | skb2 = pskb_copy(skb, GFP_ATOMIC); |
878 | else { |
879 | skb2 = skb_clone(skb, GFP_ATOMIC); |
880 | if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, |
881 | GFP_ATOMIC)) { |
882 | kfree_skb(skb2); |
883 | skb2 = NULL; |
884 | } |
885 | } |
886 | return skb2; |
887 | } |
888 | EXPORT_SYMBOL(skb_realloc_headroom); |
889 | |
890 | /** |
891 | * skb_copy_expand - copy and expand sk_buff |
892 | * @skb: buffer to copy |
893 | * @newheadroom: new free bytes at head |
894 | * @newtailroom: new free bytes at tail |
895 | * @gfp_mask: allocation priority |
896 | * |
897 | * Make a copy of both an &sk_buff and its data and while doing so |
898 | * allocate additional space. |
899 | * |
900 | * This is used when the caller wishes to modify the data and needs a |
901 | * private copy of the data to alter as well as more space for new fields. |
902 | * Returns %NULL on failure or the pointer to the buffer |
903 | * on success. The returned buffer has a reference count of 1. |
904 | * |
905 | * You must pass %GFP_ATOMIC as the allocation priority if this function |
906 | * is called from an interrupt. |
907 | */ |
908 | struct sk_buff *skb_copy_expand(const struct sk_buff *skb, |
909 | int newheadroom, int newtailroom, |
910 | gfp_t gfp_mask) |
911 | { |
912 | /* |
913 | * Allocate the copy buffer |
914 | */ |
915 | struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, |
916 | gfp_mask); |
917 | int oldheadroom = skb_headroom(skb); |
918 | int head_copy_len, head_copy_off; |
919 | int off; |
920 | |
921 | if (!n) |
922 | return NULL; |
923 | |
924 | skb_reserve(n, newheadroom); |
925 | |
926 | /* Set the tail pointer and length */ |
927 | skb_put(n, skb->len); |
928 | |
929 | head_copy_len = oldheadroom; |
930 | head_copy_off = 0; |
931 | if (newheadroom <= head_copy_len) |
932 | head_copy_len = newheadroom; |
933 | else |
934 | head_copy_off = newheadroom - head_copy_len; |
935 | |
936 | /* Copy the linear header and data. */ |
937 | if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, |
938 | skb->len + head_copy_len)) |
939 | BUG(); |
940 | |
941 | copy_skb_header(n, skb); |
942 | |
943 | off = newheadroom - oldheadroom; |
944 | n->csum_start += off; |
945 | #ifdef NET_SKBUFF_DATA_USES_OFFSET |
946 | n->transport_header += off; |
947 | n->network_header += off; |
948 | if (skb_mac_header_was_set(skb)) |
949 | n->mac_header += off; |
950 | #endif |
951 | |
952 | return n; |
953 | } |
954 | EXPORT_SYMBOL(skb_copy_expand); |
955 | |
956 | /** |
957 | * skb_pad - zero pad the tail of an skb |
958 | * @skb: buffer to pad |
959 | * @pad: space to pad |
960 | * |
961 | * Ensure that a buffer is followed by a padding area that is zero |
962 | * filled. Used by network drivers which may DMA or transfer data |
963 | * beyond the buffer end onto the wire. |
964 | * |
965 | * May return error in out of memory cases. The skb is freed on error. |
966 | */ |
967 | |
968 | int skb_pad(struct sk_buff *skb, int pad) |
969 | { |
970 | int err; |
971 | int ntail; |
972 | |
973 | /* If the skbuff is non linear tailroom is always zero.. */ |
974 | if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { |
975 | memset(skb->data+skb->len, 0, pad); |
976 | return 0; |
977 | } |
978 | |
979 | ntail = skb->data_len + pad - (skb->end - skb->tail); |
980 | if (likely(skb_cloned(skb) || ntail > 0)) { |
981 | err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); |
982 | if (unlikely(err)) |
983 | goto free_skb; |
984 | } |
985 | |
986 | /* FIXME: The use of this function with non-linear skb's really needs |
987 | * to be audited. |
988 | */ |
989 | err = skb_linearize(skb); |
990 | if (unlikely(err)) |
991 | goto free_skb; |
992 | |
993 | memset(skb->data + skb->len, 0, pad); |
994 | return 0; |
995 | |
996 | free_skb: |
997 | kfree_skb(skb); |
998 | return err; |
999 | } |
1000 | EXPORT_SYMBOL(skb_pad); |
1001 | |
1002 | /** |
1003 | * skb_put - add data to a buffer |
1004 | * @skb: buffer to use |
1005 | * @len: amount of data to add |
1006 | * |
1007 | * This function extends the used data area of the buffer. If this would |
1008 | * exceed the total buffer size the kernel will panic. A pointer to the |
1009 | * first byte of the extra data is returned. |
1010 | */ |
1011 | unsigned char *skb_put(struct sk_buff *skb, unsigned int len) |
1012 | { |
1013 | unsigned char *tmp = skb_tail_pointer(skb); |
1014 | SKB_LINEAR_ASSERT(skb); |
1015 | skb->tail += len; |
1016 | skb->len += len; |
1017 | if (unlikely(skb->tail > skb->end)) |
1018 | skb_over_panic(skb, len, __builtin_return_address(0)); |
1019 | return tmp; |
1020 | } |
1021 | EXPORT_SYMBOL(skb_put); |
1022 | |
1023 | /** |
1024 | * skb_push - add data to the start of a buffer |
1025 | * @skb: buffer to use |
1026 | * @len: amount of data to add |
1027 | * |
1028 | * This function extends the used data area of the buffer at the buffer |
1029 | * start. If this would exceed the total buffer headroom the kernel will |
1030 | * panic. A pointer to the first byte of the extra data is returned. |
1031 | */ |
1032 | unsigned char *skb_push(struct sk_buff *skb, unsigned int len) |
1033 | { |
1034 | skb->data -= len; |
1035 | skb->len += len; |
1036 | if (unlikely(skb->data<skb->head)) |
1037 | skb_under_panic(skb, len, __builtin_return_address(0)); |
1038 | return skb->data; |
1039 | } |
1040 | EXPORT_SYMBOL(skb_push); |
1041 | |
1042 | /** |
1043 | * skb_pull - remove data from the start of a buffer |
1044 | * @skb: buffer to use |
1045 | * @len: amount of data to remove |
1046 | * |
1047 | * This function removes data from the start of a buffer, returning |
1048 | * the memory to the headroom. A pointer to the next data in the buffer |
1049 | * is returned. Once the data has been pulled future pushes will overwrite |
1050 | * the old data. |
1051 | */ |
1052 | unsigned char *skb_pull(struct sk_buff *skb, unsigned int len) |
1053 | { |
1054 | return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len); |
1055 | } |
1056 | EXPORT_SYMBOL(skb_pull); |
1057 | |
1058 | /** |
1059 | * skb_trim - remove end from a buffer |
1060 | * @skb: buffer to alter |
1061 | * @len: new length |
1062 | * |
1063 | * Cut the length of a buffer down by removing data from the tail. If |
1064 | * the buffer is already under the length specified it is not modified. |
1065 | * The skb must be linear. |
1066 | */ |
1067 | void skb_trim(struct sk_buff *skb, unsigned int len) |
1068 | { |
1069 | if (skb->len > len) |
1070 | __skb_trim(skb, len); |
1071 | } |
1072 | EXPORT_SYMBOL(skb_trim); |
1073 | |
1074 | /* Trims skb to length len. It can change skb pointers. |
1075 | */ |
1076 | |
1077 | int ___pskb_trim(struct sk_buff *skb, unsigned int len) |
1078 | { |
1079 | struct sk_buff **fragp; |
1080 | struct sk_buff *frag; |
1081 | int offset = skb_headlen(skb); |
1082 | int nfrags = skb_shinfo(skb)->nr_frags; |
1083 | int i; |
1084 | int err; |
1085 | |
1086 | if (skb_cloned(skb) && |
1087 | unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) |
1088 | return err; |
1089 | |
1090 | i = 0; |
1091 | if (offset >= len) |
1092 | goto drop_pages; |
1093 | |
1094 | for (; i < nfrags; i++) { |
1095 | int end = offset + skb_shinfo(skb)->frags[i].size; |
1096 | |
1097 | if (end < len) { |
1098 | offset = end; |
1099 | continue; |
1100 | } |
1101 | |
1102 | skb_shinfo(skb)->frags[i++].size = len - offset; |
1103 | |
1104 | drop_pages: |
1105 | skb_shinfo(skb)->nr_frags = i; |
1106 | |
1107 | for (; i < nfrags; i++) |
1108 | put_page(skb_shinfo(skb)->frags[i].page); |
1109 | |
1110 | if (skb_has_frags(skb)) |
1111 | skb_drop_fraglist(skb); |
1112 | goto done; |
1113 | } |
1114 | |
1115 | for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); |
1116 | fragp = &frag->next) { |
1117 | int end = offset + frag->len; |
1118 | |
1119 | if (skb_shared(frag)) { |
1120 | struct sk_buff *nfrag; |
1121 | |
1122 | nfrag = skb_clone(frag, GFP_ATOMIC); |
1123 | if (unlikely(!nfrag)) |
1124 | return -ENOMEM; |
1125 | |
1126 | nfrag->next = frag->next; |
1127 | kfree_skb(frag); |
1128 | frag = nfrag; |
1129 | *fragp = frag; |
1130 | } |
1131 | |
1132 | if (end < len) { |
1133 | offset = end; |
1134 | continue; |
1135 | } |
1136 | |
1137 | if (end > len && |
1138 | unlikely((err = pskb_trim(frag, len - offset)))) |
1139 | return err; |
1140 | |
1141 | if (frag->next) |
1142 | skb_drop_list(&frag->next); |
1143 | break; |
1144 | } |
1145 | |
1146 | done: |
1147 | if (len > skb_headlen(skb)) { |
1148 | skb->data_len -= skb->len - len; |
1149 | skb->len = len; |
1150 | } else { |
1151 | skb->len = len; |
1152 | skb->data_len = 0; |
1153 | skb_set_tail_pointer(skb, len); |
1154 | } |
1155 | |
1156 | return 0; |
1157 | } |
1158 | EXPORT_SYMBOL(___pskb_trim); |
1159 | |
1160 | /** |
1161 | * __pskb_pull_tail - advance tail of skb header |
1162 | * @skb: buffer to reallocate |
1163 | * @delta: number of bytes to advance tail |
1164 | * |
1165 | * The function makes a sense only on a fragmented &sk_buff, |
1166 | * it expands header moving its tail forward and copying necessary |
1167 | * data from fragmented part. |
1168 | * |
1169 | * &sk_buff MUST have reference count of 1. |
1170 | * |
1171 | * Returns %NULL (and &sk_buff does not change) if pull failed |
1172 | * or value of new tail of skb in the case of success. |
1173 | * |
1174 | * All the pointers pointing into skb header may change and must be |
1175 | * reloaded after call to this function. |
1176 | */ |
1177 | |
1178 | /* Moves tail of skb head forward, copying data from fragmented part, |
1179 | * when it is necessary. |
1180 | * 1. It may fail due to malloc failure. |
1181 | * 2. It may change skb pointers. |
1182 | * |
1183 | * It is pretty complicated. Luckily, it is called only in exceptional cases. |
1184 | */ |
1185 | unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) |
1186 | { |
1187 | /* If skb has not enough free space at tail, get new one |
1188 | * plus 128 bytes for future expansions. If we have enough |
1189 | * room at tail, reallocate without expansion only if skb is cloned. |
1190 | */ |
1191 | int i, k, eat = (skb->tail + delta) - skb->end; |
1192 | |
1193 | if (eat > 0 || skb_cloned(skb)) { |
1194 | if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, |
1195 | GFP_ATOMIC)) |
1196 | return NULL; |
1197 | } |
1198 | |
1199 | if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta)) |
1200 | BUG(); |
1201 | |
1202 | /* Optimization: no fragments, no reasons to preestimate |
1203 | * size of pulled pages. Superb. |
1204 | */ |
1205 | if (!skb_has_frags(skb)) |
1206 | goto pull_pages; |
1207 | |
1208 | /* Estimate size of pulled pages. */ |
1209 | eat = delta; |
1210 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
1211 | if (skb_shinfo(skb)->frags[i].size >= eat) |
1212 | goto pull_pages; |
1213 | eat -= skb_shinfo(skb)->frags[i].size; |
1214 | } |
1215 | |
1216 | /* If we need update frag list, we are in troubles. |
1217 | * Certainly, it possible to add an offset to skb data, |
1218 | * but taking into account that pulling is expected to |
1219 | * be very rare operation, it is worth to fight against |
1220 | * further bloating skb head and crucify ourselves here instead. |
1221 | * Pure masohism, indeed. 8)8) |
1222 | */ |
1223 | if (eat) { |
1224 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
1225 | struct sk_buff *clone = NULL; |
1226 | struct sk_buff *insp = NULL; |
1227 | |
1228 | do { |
1229 | BUG_ON(!list); |
1230 | |
1231 | if (list->len <= eat) { |
1232 | /* Eaten as whole. */ |
1233 | eat -= list->len; |
1234 | list = list->next; |
1235 | insp = list; |
1236 | } else { |
1237 | /* Eaten partially. */ |
1238 | |
1239 | if (skb_shared(list)) { |
1240 | /* Sucks! We need to fork list. :-( */ |
1241 | clone = skb_clone(list, GFP_ATOMIC); |
1242 | if (!clone) |
1243 | return NULL; |
1244 | insp = list->next; |
1245 | list = clone; |
1246 | } else { |
1247 | /* This may be pulled without |
1248 | * problems. */ |
1249 | insp = list; |
1250 | } |
1251 | if (!pskb_pull(list, eat)) { |
1252 | kfree_skb(clone); |
1253 | return NULL; |
1254 | } |
1255 | break; |
1256 | } |
1257 | } while (eat); |
1258 | |
1259 | /* Free pulled out fragments. */ |
1260 | while ((list = skb_shinfo(skb)->frag_list) != insp) { |
1261 | skb_shinfo(skb)->frag_list = list->next; |
1262 | kfree_skb(list); |
1263 | } |
1264 | /* And insert new clone at head. */ |
1265 | if (clone) { |
1266 | clone->next = list; |
1267 | skb_shinfo(skb)->frag_list = clone; |
1268 | } |
1269 | } |
1270 | /* Success! Now we may commit changes to skb data. */ |
1271 | |
1272 | pull_pages: |
1273 | eat = delta; |
1274 | k = 0; |
1275 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
1276 | if (skb_shinfo(skb)->frags[i].size <= eat) { |
1277 | put_page(skb_shinfo(skb)->frags[i].page); |
1278 | eat -= skb_shinfo(skb)->frags[i].size; |
1279 | } else { |
1280 | skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; |
1281 | if (eat) { |
1282 | skb_shinfo(skb)->frags[k].page_offset += eat; |
1283 | skb_shinfo(skb)->frags[k].size -= eat; |
1284 | eat = 0; |
1285 | } |
1286 | k++; |
1287 | } |
1288 | } |
1289 | skb_shinfo(skb)->nr_frags = k; |
1290 | |
1291 | skb->tail += delta; |
1292 | skb->data_len -= delta; |
1293 | |
1294 | return skb_tail_pointer(skb); |
1295 | } |
1296 | EXPORT_SYMBOL(__pskb_pull_tail); |
1297 | |
1298 | /* Copy some data bits from skb to kernel buffer. */ |
1299 | |
1300 | int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) |
1301 | { |
1302 | int start = skb_headlen(skb); |
1303 | struct sk_buff *frag_iter; |
1304 | int i, copy; |
1305 | |
1306 | if (offset > (int)skb->len - len) |
1307 | goto fault; |
1308 | |
1309 | /* Copy header. */ |
1310 | if ((copy = start - offset) > 0) { |
1311 | if (copy > len) |
1312 | copy = len; |
1313 | skb_copy_from_linear_data_offset(skb, offset, to, copy); |
1314 | if ((len -= copy) == 0) |
1315 | return 0; |
1316 | offset += copy; |
1317 | to += copy; |
1318 | } |
1319 | |
1320 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
1321 | int end; |
1322 | |
1323 | WARN_ON(start > offset + len); |
1324 | |
1325 | end = start + skb_shinfo(skb)->frags[i].size; |
1326 | if ((copy = end - offset) > 0) { |
1327 | u8 *vaddr; |
1328 | |
1329 | if (copy > len) |
1330 | copy = len; |
1331 | |
1332 | vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); |
1333 | memcpy(to, |
1334 | vaddr + skb_shinfo(skb)->frags[i].page_offset+ |
1335 | offset - start, copy); |
1336 | kunmap_skb_frag(vaddr); |
1337 | |
1338 | if ((len -= copy) == 0) |
1339 | return 0; |
1340 | offset += copy; |
1341 | to += copy; |
1342 | } |
1343 | start = end; |
1344 | } |
1345 | |
1346 | skb_walk_frags(skb, frag_iter) { |
1347 | int end; |
1348 | |
1349 | WARN_ON(start > offset + len); |
1350 | |
1351 | end = start + frag_iter->len; |
1352 | if ((copy = end - offset) > 0) { |
1353 | if (copy > len) |
1354 | copy = len; |
1355 | if (skb_copy_bits(frag_iter, offset - start, to, copy)) |
1356 | goto fault; |
1357 | if ((len -= copy) == 0) |
1358 | return 0; |
1359 | offset += copy; |
1360 | to += copy; |
1361 | } |
1362 | start = end; |
1363 | } |
1364 | if (!len) |
1365 | return 0; |
1366 | |
1367 | fault: |
1368 | return -EFAULT; |
1369 | } |
1370 | EXPORT_SYMBOL(skb_copy_bits); |
1371 | |
1372 | /* |
1373 | * Callback from splice_to_pipe(), if we need to release some pages |
1374 | * at the end of the spd in case we error'ed out in filling the pipe. |
1375 | */ |
1376 | static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) |
1377 | { |
1378 | put_page(spd->pages[i]); |
1379 | } |
1380 | |
1381 | static inline struct page *linear_to_page(struct page *page, unsigned int *len, |
1382 | unsigned int *offset, |
1383 | struct sk_buff *skb, struct sock *sk) |
1384 | { |
1385 | struct page *p = sk->sk_sndmsg_page; |
1386 | unsigned int off; |
1387 | |
1388 | if (!p) { |
1389 | new_page: |
1390 | p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0); |
1391 | if (!p) |
1392 | return NULL; |
1393 | |
1394 | off = sk->sk_sndmsg_off = 0; |
1395 | /* hold one ref to this page until it's full */ |
1396 | } else { |
1397 | unsigned int mlen; |
1398 | |
1399 | off = sk->sk_sndmsg_off; |
1400 | mlen = PAGE_SIZE - off; |
1401 | if (mlen < 64 && mlen < *len) { |
1402 | put_page(p); |
1403 | goto new_page; |
1404 | } |
1405 | |
1406 | *len = min_t(unsigned int, *len, mlen); |
1407 | } |
1408 | |
1409 | memcpy(page_address(p) + off, page_address(page) + *offset, *len); |
1410 | sk->sk_sndmsg_off += *len; |
1411 | *offset = off; |
1412 | get_page(p); |
1413 | |
1414 | return p; |
1415 | } |
1416 | |
1417 | /* |
1418 | * Fill page/offset/length into spd, if it can hold more pages. |
1419 | */ |
1420 | static inline int spd_fill_page(struct splice_pipe_desc *spd, struct page *page, |
1421 | unsigned int *len, unsigned int offset, |
1422 | struct sk_buff *skb, int linear, |
1423 | struct sock *sk) |
1424 | { |
1425 | if (unlikely(spd->nr_pages == PIPE_BUFFERS)) |
1426 | return 1; |
1427 | |
1428 | if (linear) { |
1429 | page = linear_to_page(page, len, &offset, skb, sk); |
1430 | if (!page) |
1431 | return 1; |
1432 | } else |
1433 | get_page(page); |
1434 | |
1435 | spd->pages[spd->nr_pages] = page; |
1436 | spd->partial[spd->nr_pages].len = *len; |
1437 | spd->partial[spd->nr_pages].offset = offset; |
1438 | spd->nr_pages++; |
1439 | |
1440 | return 0; |
1441 | } |
1442 | |
1443 | static inline void __segment_seek(struct page **page, unsigned int *poff, |
1444 | unsigned int *plen, unsigned int off) |
1445 | { |
1446 | unsigned long n; |
1447 | |
1448 | *poff += off; |
1449 | n = *poff / PAGE_SIZE; |
1450 | if (n) |
1451 | *page = nth_page(*page, n); |
1452 | |
1453 | *poff = *poff % PAGE_SIZE; |
1454 | *plen -= off; |
1455 | } |
1456 | |
1457 | static inline int __splice_segment(struct page *page, unsigned int poff, |
1458 | unsigned int plen, unsigned int *off, |
1459 | unsigned int *len, struct sk_buff *skb, |
1460 | struct splice_pipe_desc *spd, int linear, |
1461 | struct sock *sk) |
1462 | { |
1463 | if (!*len) |
1464 | return 1; |
1465 | |
1466 | /* skip this segment if already processed */ |
1467 | if (*off >= plen) { |
1468 | *off -= plen; |
1469 | return 0; |
1470 | } |
1471 | |
1472 | /* ignore any bits we already processed */ |
1473 | if (*off) { |
1474 | __segment_seek(&page, &poff, &plen, *off); |
1475 | *off = 0; |
1476 | } |
1477 | |
1478 | do { |
1479 | unsigned int flen = min(*len, plen); |
1480 | |
1481 | /* the linear region may spread across several pages */ |
1482 | flen = min_t(unsigned int, flen, PAGE_SIZE - poff); |
1483 | |
1484 | if (spd_fill_page(spd, page, &flen, poff, skb, linear, sk)) |
1485 | return 1; |
1486 | |
1487 | __segment_seek(&page, &poff, &plen, flen); |
1488 | *len -= flen; |
1489 | |
1490 | } while (*len && plen); |
1491 | |
1492 | return 0; |
1493 | } |
1494 | |
1495 | /* |
1496 | * Map linear and fragment data from the skb to spd. It reports failure if the |
1497 | * pipe is full or if we already spliced the requested length. |
1498 | */ |
1499 | static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset, |
1500 | unsigned int *len, struct splice_pipe_desc *spd, |
1501 | struct sock *sk) |
1502 | { |
1503 | int seg; |
1504 | |
1505 | /* |
1506 | * map the linear part |
1507 | */ |
1508 | if (__splice_segment(virt_to_page(skb->data), |
1509 | (unsigned long) skb->data & (PAGE_SIZE - 1), |
1510 | skb_headlen(skb), |
1511 | offset, len, skb, spd, 1, sk)) |
1512 | return 1; |
1513 | |
1514 | /* |
1515 | * then map the fragments |
1516 | */ |
1517 | for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { |
1518 | const skb_frag_t *f = &skb_shinfo(skb)->frags[seg]; |
1519 | |
1520 | if (__splice_segment(f->page, f->page_offset, f->size, |
1521 | offset, len, skb, spd, 0, sk)) |
1522 | return 1; |
1523 | } |
1524 | |
1525 | return 0; |
1526 | } |
1527 | |
1528 | /* |
1529 | * Map data from the skb to a pipe. Should handle both the linear part, |
1530 | * the fragments, and the frag list. It does NOT handle frag lists within |
1531 | * the frag list, if such a thing exists. We'd probably need to recurse to |
1532 | * handle that cleanly. |
1533 | */ |
1534 | int skb_splice_bits(struct sk_buff *skb, unsigned int offset, |
1535 | struct pipe_inode_info *pipe, unsigned int tlen, |
1536 | unsigned int flags) |
1537 | { |
1538 | struct partial_page partial[PIPE_BUFFERS]; |
1539 | struct page *pages[PIPE_BUFFERS]; |
1540 | struct splice_pipe_desc spd = { |
1541 | .pages = pages, |
1542 | .partial = partial, |
1543 | .flags = flags, |
1544 | .ops = &sock_pipe_buf_ops, |
1545 | .spd_release = sock_spd_release, |
1546 | }; |
1547 | struct sk_buff *frag_iter; |
1548 | struct sock *sk = skb->sk; |
1549 | |
1550 | /* |
1551 | * __skb_splice_bits() only fails if the output has no room left, |
1552 | * so no point in going over the frag_list for the error case. |
1553 | */ |
1554 | if (__skb_splice_bits(skb, &offset, &tlen, &spd, sk)) |
1555 | goto done; |
1556 | else if (!tlen) |
1557 | goto done; |
1558 | |
1559 | /* |
1560 | * now see if we have a frag_list to map |
1561 | */ |
1562 | skb_walk_frags(skb, frag_iter) { |
1563 | if (!tlen) |
1564 | break; |
1565 | if (__skb_splice_bits(frag_iter, &offset, &tlen, &spd, sk)) |
1566 | break; |
1567 | } |
1568 | |
1569 | done: |
1570 | if (spd.nr_pages) { |
1571 | int ret; |
1572 | |
1573 | /* |
1574 | * Drop the socket lock, otherwise we have reverse |
1575 | * locking dependencies between sk_lock and i_mutex |
1576 | * here as compared to sendfile(). We enter here |
1577 | * with the socket lock held, and splice_to_pipe() will |
1578 | * grab the pipe inode lock. For sendfile() emulation, |
1579 | * we call into ->sendpage() with the i_mutex lock held |
1580 | * and networking will grab the socket lock. |
1581 | */ |
1582 | release_sock(sk); |
1583 | ret = splice_to_pipe(pipe, &spd); |
1584 | lock_sock(sk); |
1585 | return ret; |
1586 | } |
1587 | |
1588 | return 0; |
1589 | } |
1590 | |
1591 | /** |
1592 | * skb_store_bits - store bits from kernel buffer to skb |
1593 | * @skb: destination buffer |
1594 | * @offset: offset in destination |
1595 | * @from: source buffer |
1596 | * @len: number of bytes to copy |
1597 | * |
1598 | * Copy the specified number of bytes from the source buffer to the |
1599 | * destination skb. This function handles all the messy bits of |
1600 | * traversing fragment lists and such. |
1601 | */ |
1602 | |
1603 | int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len) |
1604 | { |
1605 | int start = skb_headlen(skb); |
1606 | struct sk_buff *frag_iter; |
1607 | int i, copy; |
1608 | |
1609 | if (offset > (int)skb->len - len) |
1610 | goto fault; |
1611 | |
1612 | if ((copy = start - offset) > 0) { |
1613 | if (copy > len) |
1614 | copy = len; |
1615 | skb_copy_to_linear_data_offset(skb, offset, from, copy); |
1616 | if ((len -= copy) == 0) |
1617 | return 0; |
1618 | offset += copy; |
1619 | from += copy; |
1620 | } |
1621 | |
1622 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
1623 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
1624 | int end; |
1625 | |
1626 | WARN_ON(start > offset + len); |
1627 | |
1628 | end = start + frag->size; |
1629 | if ((copy = end - offset) > 0) { |
1630 | u8 *vaddr; |
1631 | |
1632 | if (copy > len) |
1633 | copy = len; |
1634 | |
1635 | vaddr = kmap_skb_frag(frag); |
1636 | memcpy(vaddr + frag->page_offset + offset - start, |
1637 | from, copy); |
1638 | kunmap_skb_frag(vaddr); |
1639 | |
1640 | if ((len -= copy) == 0) |
1641 | return 0; |
1642 | offset += copy; |
1643 | from += copy; |
1644 | } |
1645 | start = end; |
1646 | } |
1647 | |
1648 | skb_walk_frags(skb, frag_iter) { |
1649 | int end; |
1650 | |
1651 | WARN_ON(start > offset + len); |
1652 | |
1653 | end = start + frag_iter->len; |
1654 | if ((copy = end - offset) > 0) { |
1655 | if (copy > len) |
1656 | copy = len; |
1657 | if (skb_store_bits(frag_iter, offset - start, |
1658 | from, copy)) |
1659 | goto fault; |
1660 | if ((len -= copy) == 0) |
1661 | return 0; |
1662 | offset += copy; |
1663 | from += copy; |
1664 | } |
1665 | start = end; |
1666 | } |
1667 | if (!len) |
1668 | return 0; |
1669 | |
1670 | fault: |
1671 | return -EFAULT; |
1672 | } |
1673 | EXPORT_SYMBOL(skb_store_bits); |
1674 | |
1675 | /* Checksum skb data. */ |
1676 | |
1677 | __wsum skb_checksum(const struct sk_buff *skb, int offset, |
1678 | int len, __wsum csum) |
1679 | { |
1680 | int start = skb_headlen(skb); |
1681 | int i, copy = start - offset; |
1682 | struct sk_buff *frag_iter; |
1683 | int pos = 0; |
1684 | |
1685 | /* Checksum header. */ |
1686 | if (copy > 0) { |
1687 | if (copy > len) |
1688 | copy = len; |
1689 | csum = csum_partial(skb->data + offset, copy, csum); |
1690 | if ((len -= copy) == 0) |
1691 | return csum; |
1692 | offset += copy; |
1693 | pos = copy; |
1694 | } |
1695 | |
1696 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
1697 | int end; |
1698 | |
1699 | WARN_ON(start > offset + len); |
1700 | |
1701 | end = start + skb_shinfo(skb)->frags[i].size; |
1702 | if ((copy = end - offset) > 0) { |
1703 | __wsum csum2; |
1704 | u8 *vaddr; |
1705 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
1706 | |
1707 | if (copy > len) |
1708 | copy = len; |
1709 | vaddr = kmap_skb_frag(frag); |
1710 | csum2 = csum_partial(vaddr + frag->page_offset + |
1711 | offset - start, copy, 0); |
1712 | kunmap_skb_frag(vaddr); |
1713 | csum = csum_block_add(csum, csum2, pos); |
1714 | if (!(len -= copy)) |
1715 | return csum; |
1716 | offset += copy; |
1717 | pos += copy; |
1718 | } |
1719 | start = end; |
1720 | } |
1721 | |
1722 | skb_walk_frags(skb, frag_iter) { |
1723 | int end; |
1724 | |
1725 | WARN_ON(start > offset + len); |
1726 | |
1727 | end = start + frag_iter->len; |
1728 | if ((copy = end - offset) > 0) { |
1729 | __wsum csum2; |
1730 | if (copy > len) |
1731 | copy = len; |
1732 | csum2 = skb_checksum(frag_iter, offset - start, |
1733 | copy, 0); |
1734 | csum = csum_block_add(csum, csum2, pos); |
1735 | if ((len -= copy) == 0) |
1736 | return csum; |
1737 | offset += copy; |
1738 | pos += copy; |
1739 | } |
1740 | start = end; |
1741 | } |
1742 | BUG_ON(len); |
1743 | |
1744 | return csum; |
1745 | } |
1746 | EXPORT_SYMBOL(skb_checksum); |
1747 | |
1748 | /* Both of above in one bottle. */ |
1749 | |
1750 | __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, |
1751 | u8 *to, int len, __wsum csum) |
1752 | { |
1753 | int start = skb_headlen(skb); |
1754 | int i, copy = start - offset; |
1755 | struct sk_buff *frag_iter; |
1756 | int pos = 0; |
1757 | |
1758 | /* Copy header. */ |
1759 | if (copy > 0) { |
1760 | if (copy > len) |
1761 | copy = len; |
1762 | csum = csum_partial_copy_nocheck(skb->data + offset, to, |
1763 | copy, csum); |
1764 | if ((len -= copy) == 0) |
1765 | return csum; |
1766 | offset += copy; |
1767 | to += copy; |
1768 | pos = copy; |
1769 | } |
1770 | |
1771 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
1772 | int end; |
1773 | |
1774 | WARN_ON(start > offset + len); |
1775 | |
1776 | end = start + skb_shinfo(skb)->frags[i].size; |
1777 | if ((copy = end - offset) > 0) { |
1778 | __wsum csum2; |
1779 | u8 *vaddr; |
1780 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
1781 | |
1782 | if (copy > len) |
1783 | copy = len; |
1784 | vaddr = kmap_skb_frag(frag); |
1785 | csum2 = csum_partial_copy_nocheck(vaddr + |
1786 | frag->page_offset + |
1787 | offset - start, to, |
1788 | copy, 0); |
1789 | kunmap_skb_frag(vaddr); |
1790 | csum = csum_block_add(csum, csum2, pos); |
1791 | if (!(len -= copy)) |
1792 | return csum; |
1793 | offset += copy; |
1794 | to += copy; |
1795 | pos += copy; |
1796 | } |
1797 | start = end; |
1798 | } |
1799 | |
1800 | skb_walk_frags(skb, frag_iter) { |
1801 | __wsum csum2; |
1802 | int end; |
1803 | |
1804 | WARN_ON(start > offset + len); |
1805 | |
1806 | end = start + frag_iter->len; |
1807 | if ((copy = end - offset) > 0) { |
1808 | if (copy > len) |
1809 | copy = len; |
1810 | csum2 = skb_copy_and_csum_bits(frag_iter, |
1811 | offset - start, |
1812 | to, copy, 0); |
1813 | csum = csum_block_add(csum, csum2, pos); |
1814 | if ((len -= copy) == 0) |
1815 | return csum; |
1816 | offset += copy; |
1817 | to += copy; |
1818 | pos += copy; |
1819 | } |
1820 | start = end; |
1821 | } |
1822 | BUG_ON(len); |
1823 | return csum; |
1824 | } |
1825 | EXPORT_SYMBOL(skb_copy_and_csum_bits); |
1826 | |
1827 | void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) |
1828 | { |
1829 | __wsum csum; |
1830 | long csstart; |
1831 | |
1832 | if (skb->ip_summed == CHECKSUM_PARTIAL) |
1833 | csstart = skb->csum_start - skb_headroom(skb); |
1834 | else |
1835 | csstart = skb_headlen(skb); |
1836 | |
1837 | BUG_ON(csstart > skb_headlen(skb)); |
1838 | |
1839 | skb_copy_from_linear_data(skb, to, csstart); |
1840 | |
1841 | csum = 0; |
1842 | if (csstart != skb->len) |
1843 | csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, |
1844 | skb->len - csstart, 0); |
1845 | |
1846 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
1847 | long csstuff = csstart + skb->csum_offset; |
1848 | |
1849 | *((__sum16 *)(to + csstuff)) = csum_fold(csum); |
1850 | } |
1851 | } |
1852 | EXPORT_SYMBOL(skb_copy_and_csum_dev); |
1853 | |
1854 | /** |
1855 | * skb_dequeue - remove from the head of the queue |
1856 | * @list: list to dequeue from |
1857 | * |
1858 | * Remove the head of the list. The list lock is taken so the function |
1859 | * may be used safely with other locking list functions. The head item is |
1860 | * returned or %NULL if the list is empty. |
1861 | */ |
1862 | |
1863 | struct sk_buff *skb_dequeue(struct sk_buff_head *list) |
1864 | { |
1865 | unsigned long flags; |
1866 | struct sk_buff *result; |
1867 | |
1868 | spin_lock_irqsave(&list->lock, flags); |
1869 | result = __skb_dequeue(list); |
1870 | spin_unlock_irqrestore(&list->lock, flags); |
1871 | return result; |
1872 | } |
1873 | EXPORT_SYMBOL(skb_dequeue); |
1874 | |
1875 | /** |
1876 | * skb_dequeue_tail - remove from the tail of the queue |
1877 | * @list: list to dequeue from |
1878 | * |
1879 | * Remove the tail of the list. The list lock is taken so the function |
1880 | * may be used safely with other locking list functions. The tail item is |
1881 | * returned or %NULL if the list is empty. |
1882 | */ |
1883 | struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) |
1884 | { |
1885 | unsigned long flags; |
1886 | struct sk_buff *result; |
1887 | |
1888 | spin_lock_irqsave(&list->lock, flags); |
1889 | result = __skb_dequeue_tail(list); |
1890 | spin_unlock_irqrestore(&list->lock, flags); |
1891 | return result; |
1892 | } |
1893 | EXPORT_SYMBOL(skb_dequeue_tail); |
1894 | |
1895 | /** |
1896 | * skb_queue_purge - empty a list |
1897 | * @list: list to empty |
1898 | * |
1899 | * Delete all buffers on an &sk_buff list. Each buffer is removed from |
1900 | * the list and one reference dropped. This function takes the list |
1901 | * lock and is atomic with respect to other list locking functions. |
1902 | */ |
1903 | void skb_queue_purge(struct sk_buff_head *list) |
1904 | { |
1905 | struct sk_buff *skb; |
1906 | while ((skb = skb_dequeue(list)) != NULL) |
1907 | kfree_skb(skb); |
1908 | } |
1909 | EXPORT_SYMBOL(skb_queue_purge); |
1910 | |
1911 | /** |
1912 | * skb_queue_head - queue a buffer at the list head |
1913 | * @list: list to use |
1914 | * @newsk: buffer to queue |
1915 | * |
1916 | * Queue a buffer at the start of the list. This function takes the |
1917 | * list lock and can be used safely with other locking &sk_buff functions |
1918 | * safely. |
1919 | * |
1920 | * A buffer cannot be placed on two lists at the same time. |
1921 | */ |
1922 | void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) |
1923 | { |
1924 | unsigned long flags; |
1925 | |
1926 | spin_lock_irqsave(&list->lock, flags); |
1927 | __skb_queue_head(list, newsk); |
1928 | spin_unlock_irqrestore(&list->lock, flags); |
1929 | } |
1930 | EXPORT_SYMBOL(skb_queue_head); |
1931 | |
1932 | /** |
1933 | * skb_queue_tail - queue a buffer at the list tail |
1934 | * @list: list to use |
1935 | * @newsk: buffer to queue |
1936 | * |
1937 | * Queue a buffer at the tail of the list. This function takes the |
1938 | * list lock and can be used safely with other locking &sk_buff functions |
1939 | * safely. |
1940 | * |
1941 | * A buffer cannot be placed on two lists at the same time. |
1942 | */ |
1943 | void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) |
1944 | { |
1945 | unsigned long flags; |
1946 | |
1947 | spin_lock_irqsave(&list->lock, flags); |
1948 | __skb_queue_tail(list, newsk); |
1949 | spin_unlock_irqrestore(&list->lock, flags); |
1950 | } |
1951 | EXPORT_SYMBOL(skb_queue_tail); |
1952 | |
1953 | /** |
1954 | * skb_unlink - remove a buffer from a list |
1955 | * @skb: buffer to remove |
1956 | * @list: list to use |
1957 | * |
1958 | * Remove a packet from a list. The list locks are taken and this |
1959 | * function is atomic with respect to other list locked calls |
1960 | * |
1961 | * You must know what list the SKB is on. |
1962 | */ |
1963 | void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) |
1964 | { |
1965 | unsigned long flags; |
1966 | |
1967 | spin_lock_irqsave(&list->lock, flags); |
1968 | __skb_unlink(skb, list); |
1969 | spin_unlock_irqrestore(&list->lock, flags); |
1970 | } |
1971 | EXPORT_SYMBOL(skb_unlink); |
1972 | |
1973 | /** |
1974 | * skb_append - append a buffer |
1975 | * @old: buffer to insert after |
1976 | * @newsk: buffer to insert |
1977 | * @list: list to use |
1978 | * |
1979 | * Place a packet after a given packet in a list. The list locks are taken |
1980 | * and this function is atomic with respect to other list locked calls. |
1981 | * A buffer cannot be placed on two lists at the same time. |
1982 | */ |
1983 | void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) |
1984 | { |
1985 | unsigned long flags; |
1986 | |
1987 | spin_lock_irqsave(&list->lock, flags); |
1988 | __skb_queue_after(list, old, newsk); |
1989 | spin_unlock_irqrestore(&list->lock, flags); |
1990 | } |
1991 | EXPORT_SYMBOL(skb_append); |
1992 | |
1993 | /** |
1994 | * skb_insert - insert a buffer |
1995 | * @old: buffer to insert before |
1996 | * @newsk: buffer to insert |
1997 | * @list: list to use |
1998 | * |
1999 | * Place a packet before a given packet in a list. The list locks are |
2000 | * taken and this function is atomic with respect to other list locked |
2001 | * calls. |
2002 | * |
2003 | * A buffer cannot be placed on two lists at the same time. |
2004 | */ |
2005 | void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) |
2006 | { |
2007 | unsigned long flags; |
2008 | |
2009 | spin_lock_irqsave(&list->lock, flags); |
2010 | __skb_insert(newsk, old->prev, old, list); |
2011 | spin_unlock_irqrestore(&list->lock, flags); |
2012 | } |
2013 | EXPORT_SYMBOL(skb_insert); |
2014 | |
2015 | static inline void skb_split_inside_header(struct sk_buff *skb, |
2016 | struct sk_buff* skb1, |
2017 | const u32 len, const int pos) |
2018 | { |
2019 | int i; |
2020 | |
2021 | skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len), |
2022 | pos - len); |
2023 | /* And move data appendix as is. */ |
2024 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
2025 | skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; |
2026 | |
2027 | skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; |
2028 | skb_shinfo(skb)->nr_frags = 0; |
2029 | skb1->data_len = skb->data_len; |
2030 | skb1->len += skb1->data_len; |
2031 | skb->data_len = 0; |
2032 | skb->len = len; |
2033 | skb_set_tail_pointer(skb, len); |
2034 | } |
2035 | |
2036 | static inline void skb_split_no_header(struct sk_buff *skb, |
2037 | struct sk_buff* skb1, |
2038 | const u32 len, int pos) |
2039 | { |
2040 | int i, k = 0; |
2041 | const int nfrags = skb_shinfo(skb)->nr_frags; |
2042 | |
2043 | skb_shinfo(skb)->nr_frags = 0; |
2044 | skb1->len = skb1->data_len = skb->len - len; |
2045 | skb->len = len; |
2046 | skb->data_len = len - pos; |
2047 | |
2048 | for (i = 0; i < nfrags; i++) { |
2049 | int size = skb_shinfo(skb)->frags[i].size; |
2050 | |
2051 | if (pos + size > len) { |
2052 | skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; |
2053 | |
2054 | if (pos < len) { |
2055 | /* Split frag. |
2056 | * We have two variants in this case: |
2057 | * 1. Move all the frag to the second |
2058 | * part, if it is possible. F.e. |
2059 | * this approach is mandatory for TUX, |
2060 | * where splitting is expensive. |
2061 | * 2. Split is accurately. We make this. |
2062 | */ |
2063 | get_page(skb_shinfo(skb)->frags[i].page); |
2064 | skb_shinfo(skb1)->frags[0].page_offset += len - pos; |
2065 | skb_shinfo(skb1)->frags[0].size -= len - pos; |
2066 | skb_shinfo(skb)->frags[i].size = len - pos; |
2067 | skb_shinfo(skb)->nr_frags++; |
2068 | } |
2069 | k++; |
2070 | } else |
2071 | skb_shinfo(skb)->nr_frags++; |
2072 | pos += size; |
2073 | } |
2074 | skb_shinfo(skb1)->nr_frags = k; |
2075 | } |
2076 | |
2077 | /** |
2078 | * skb_split - Split fragmented skb to two parts at length len. |
2079 | * @skb: the buffer to split |
2080 | * @skb1: the buffer to receive the second part |
2081 | * @len: new length for skb |
2082 | */ |
2083 | void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) |
2084 | { |
2085 | int pos = skb_headlen(skb); |
2086 | |
2087 | if (len < pos) /* Split line is inside header. */ |
2088 | skb_split_inside_header(skb, skb1, len, pos); |
2089 | else /* Second chunk has no header, nothing to copy. */ |
2090 | skb_split_no_header(skb, skb1, len, pos); |
2091 | } |
2092 | EXPORT_SYMBOL(skb_split); |
2093 | |
2094 | /* Shifting from/to a cloned skb is a no-go. |
2095 | * |
2096 | * Caller cannot keep skb_shinfo related pointers past calling here! |
2097 | */ |
2098 | static int skb_prepare_for_shift(struct sk_buff *skb) |
2099 | { |
2100 | return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC); |
2101 | } |
2102 | |
2103 | /** |
2104 | * skb_shift - Shifts paged data partially from skb to another |
2105 | * @tgt: buffer into which tail data gets added |
2106 | * @skb: buffer from which the paged data comes from |
2107 | * @shiftlen: shift up to this many bytes |
2108 | * |
2109 | * Attempts to shift up to shiftlen worth of bytes, which may be less than |
2110 | * the length of the skb, from tgt to skb. Returns number bytes shifted. |
2111 | * It's up to caller to free skb if everything was shifted. |
2112 | * |
2113 | * If @tgt runs out of frags, the whole operation is aborted. |
2114 | * |
2115 | * Skb cannot include anything else but paged data while tgt is allowed |
2116 | * to have non-paged data as well. |
2117 | * |
2118 | * TODO: full sized shift could be optimized but that would need |
2119 | * specialized skb free'er to handle frags without up-to-date nr_frags. |
2120 | */ |
2121 | int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) |
2122 | { |
2123 | int from, to, merge, todo; |
2124 | struct skb_frag_struct *fragfrom, *fragto; |
2125 | |
2126 | BUG_ON(shiftlen > skb->len); |
2127 | BUG_ON(skb_headlen(skb)); /* Would corrupt stream */ |
2128 | |
2129 | todo = shiftlen; |
2130 | from = 0; |
2131 | to = skb_shinfo(tgt)->nr_frags; |
2132 | fragfrom = &skb_shinfo(skb)->frags[from]; |
2133 | |
2134 | /* Actual merge is delayed until the point when we know we can |
2135 | * commit all, so that we don't have to undo partial changes |
2136 | */ |
2137 | if (!to || |
2138 | !skb_can_coalesce(tgt, to, fragfrom->page, fragfrom->page_offset)) { |
2139 | merge = -1; |
2140 | } else { |
2141 | merge = to - 1; |
2142 | |
2143 | todo -= fragfrom->size; |
2144 | if (todo < 0) { |
2145 | if (skb_prepare_for_shift(skb) || |
2146 | skb_prepare_for_shift(tgt)) |
2147 | return 0; |
2148 | |
2149 | /* All previous frag pointers might be stale! */ |
2150 | fragfrom = &skb_shinfo(skb)->frags[from]; |
2151 | fragto = &skb_shinfo(tgt)->frags[merge]; |
2152 | |
2153 | fragto->size += shiftlen; |
2154 | fragfrom->size -= shiftlen; |
2155 | fragfrom->page_offset += shiftlen; |
2156 | |
2157 | goto onlymerged; |
2158 | } |
2159 | |
2160 | from++; |
2161 | } |
2162 | |
2163 | /* Skip full, not-fitting skb to avoid expensive operations */ |
2164 | if ((shiftlen == skb->len) && |
2165 | (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to)) |
2166 | return 0; |
2167 | |
2168 | if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt)) |
2169 | return 0; |
2170 | |
2171 | while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) { |
2172 | if (to == MAX_SKB_FRAGS) |
2173 | return 0; |
2174 | |
2175 | fragfrom = &skb_shinfo(skb)->frags[from]; |
2176 | fragto = &skb_shinfo(tgt)->frags[to]; |
2177 | |
2178 | if (todo >= fragfrom->size) { |
2179 | *fragto = *fragfrom; |
2180 | todo -= fragfrom->size; |
2181 | from++; |
2182 | to++; |
2183 | |
2184 | } else { |
2185 | get_page(fragfrom->page); |
2186 | fragto->page = fragfrom->page; |
2187 | fragto->page_offset = fragfrom->page_offset; |
2188 | fragto->size = todo; |
2189 | |
2190 | fragfrom->page_offset += todo; |
2191 | fragfrom->size -= todo; |
2192 | todo = 0; |
2193 | |
2194 | to++; |
2195 | break; |
2196 | } |
2197 | } |
2198 | |
2199 | /* Ready to "commit" this state change to tgt */ |
2200 | skb_shinfo(tgt)->nr_frags = to; |
2201 | |
2202 | if (merge >= 0) { |
2203 | fragfrom = &skb_shinfo(skb)->frags[0]; |
2204 | fragto = &skb_shinfo(tgt)->frags[merge]; |
2205 | |
2206 | fragto->size += fragfrom->size; |
2207 | put_page(fragfrom->page); |
2208 | } |
2209 | |
2210 | /* Reposition in the original skb */ |
2211 | to = 0; |
2212 | while (from < skb_shinfo(skb)->nr_frags) |
2213 | skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++]; |
2214 | skb_shinfo(skb)->nr_frags = to; |
2215 | |
2216 | BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags); |
2217 | |
2218 | onlymerged: |
2219 | /* Most likely the tgt won't ever need its checksum anymore, skb on |
2220 | * the other hand might need it if it needs to be resent |
2221 | */ |
2222 | tgt->ip_summed = CHECKSUM_PARTIAL; |
2223 | skb->ip_summed = CHECKSUM_PARTIAL; |
2224 | |
2225 | /* Yak, is it really working this way? Some helper please? */ |
2226 | skb->len -= shiftlen; |
2227 | skb->data_len -= shiftlen; |
2228 | skb->truesize -= shiftlen; |
2229 | tgt->len += shiftlen; |
2230 | tgt->data_len += shiftlen; |
2231 | tgt->truesize += shiftlen; |
2232 | |
2233 | return shiftlen; |
2234 | } |
2235 | |
2236 | /** |
2237 | * skb_prepare_seq_read - Prepare a sequential read of skb data |
2238 | * @skb: the buffer to read |
2239 | * @from: lower offset of data to be read |
2240 | * @to: upper offset of data to be read |
2241 | * @st: state variable |
2242 | * |
2243 | * Initializes the specified state variable. Must be called before |
2244 | * invoking skb_seq_read() for the first time. |
2245 | */ |
2246 | void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, |
2247 | unsigned int to, struct skb_seq_state *st) |
2248 | { |
2249 | st->lower_offset = from; |
2250 | st->upper_offset = to; |
2251 | st->root_skb = st->cur_skb = skb; |
2252 | st->frag_idx = st->stepped_offset = 0; |
2253 | st->frag_data = NULL; |
2254 | } |
2255 | EXPORT_SYMBOL(skb_prepare_seq_read); |
2256 | |
2257 | /** |
2258 | * skb_seq_read - Sequentially read skb data |
2259 | * @consumed: number of bytes consumed by the caller so far |
2260 | * @data: destination pointer for data to be returned |
2261 | * @st: state variable |
2262 | * |
2263 | * Reads a block of skb data at &consumed relative to the |
2264 | * lower offset specified to skb_prepare_seq_read(). Assigns |
2265 | * the head of the data block to &data and returns the length |
2266 | * of the block or 0 if the end of the skb data or the upper |
2267 | * offset has been reached. |
2268 | * |
2269 | * The caller is not required to consume all of the data |
2270 | * returned, i.e. &consumed is typically set to the number |
2271 | * of bytes already consumed and the next call to |
2272 | * skb_seq_read() will return the remaining part of the block. |
2273 | * |
2274 | * Note 1: The size of each block of data returned can be arbitary, |
2275 | * this limitation is the cost for zerocopy seqeuental |
2276 | * reads of potentially non linear data. |
2277 | * |
2278 | * Note 2: Fragment lists within fragments are not implemented |
2279 | * at the moment, state->root_skb could be replaced with |
2280 | * a stack for this purpose. |
2281 | */ |
2282 | unsigned int skb_seq_read(unsigned int consumed, const u8 **data, |
2283 | struct skb_seq_state *st) |
2284 | { |
2285 | unsigned int block_limit, abs_offset = consumed + st->lower_offset; |
2286 | skb_frag_t *frag; |
2287 | |
2288 | if (unlikely(abs_offset >= st->upper_offset)) |
2289 | return 0; |
2290 | |
2291 | next_skb: |
2292 | block_limit = skb_headlen(st->cur_skb) + st->stepped_offset; |
2293 | |
2294 | if (abs_offset < block_limit && !st->frag_data) { |
2295 | *data = st->cur_skb->data + (abs_offset - st->stepped_offset); |
2296 | return block_limit - abs_offset; |
2297 | } |
2298 | |
2299 | if (st->frag_idx == 0 && !st->frag_data) |
2300 | st->stepped_offset += skb_headlen(st->cur_skb); |
2301 | |
2302 | while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { |
2303 | frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; |
2304 | block_limit = frag->size + st->stepped_offset; |
2305 | |
2306 | if (abs_offset < block_limit) { |
2307 | if (!st->frag_data) |
2308 | st->frag_data = kmap_skb_frag(frag); |
2309 | |
2310 | *data = (u8 *) st->frag_data + frag->page_offset + |
2311 | (abs_offset - st->stepped_offset); |
2312 | |
2313 | return block_limit - abs_offset; |
2314 | } |
2315 | |
2316 | if (st->frag_data) { |
2317 | kunmap_skb_frag(st->frag_data); |
2318 | st->frag_data = NULL; |
2319 | } |
2320 | |
2321 | st->frag_idx++; |
2322 | st->stepped_offset += frag->size; |
2323 | } |
2324 | |
2325 | if (st->frag_data) { |
2326 | kunmap_skb_frag(st->frag_data); |
2327 | st->frag_data = NULL; |
2328 | } |
2329 | |
2330 | if (st->root_skb == st->cur_skb && skb_has_frags(st->root_skb)) { |
2331 | st->cur_skb = skb_shinfo(st->root_skb)->frag_list; |
2332 | st->frag_idx = 0; |
2333 | goto next_skb; |
2334 | } else if (st->cur_skb->next) { |
2335 | st->cur_skb = st->cur_skb->next; |
2336 | st->frag_idx = 0; |
2337 | goto next_skb; |
2338 | } |
2339 | |
2340 | return 0; |
2341 | } |
2342 | EXPORT_SYMBOL(skb_seq_read); |
2343 | |
2344 | /** |
2345 | * skb_abort_seq_read - Abort a sequential read of skb data |
2346 | * @st: state variable |
2347 | * |
2348 | * Must be called if skb_seq_read() was not called until it |
2349 | * returned 0. |
2350 | */ |
2351 | void skb_abort_seq_read(struct skb_seq_state *st) |
2352 | { |
2353 | if (st->frag_data) |
2354 | kunmap_skb_frag(st->frag_data); |
2355 | } |
2356 | EXPORT_SYMBOL(skb_abort_seq_read); |
2357 | |
2358 | #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) |
2359 | |
2360 | static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, |
2361 | struct ts_config *conf, |
2362 | struct ts_state *state) |
2363 | { |
2364 | return skb_seq_read(offset, text, TS_SKB_CB(state)); |
2365 | } |
2366 | |
2367 | static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) |
2368 | { |
2369 | skb_abort_seq_read(TS_SKB_CB(state)); |
2370 | } |
2371 | |
2372 | /** |
2373 | * skb_find_text - Find a text pattern in skb data |
2374 | * @skb: the buffer to look in |
2375 | * @from: search offset |
2376 | * @to: search limit |
2377 | * @config: textsearch configuration |
2378 | * @state: uninitialized textsearch state variable |
2379 | * |
2380 | * Finds a pattern in the skb data according to the specified |
2381 | * textsearch configuration. Use textsearch_next() to retrieve |
2382 | * subsequent occurrences of the pattern. Returns the offset |
2383 | * to the first occurrence or UINT_MAX if no match was found. |
2384 | */ |
2385 | unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, |
2386 | unsigned int to, struct ts_config *config, |
2387 | struct ts_state *state) |
2388 | { |
2389 | unsigned int ret; |
2390 | |
2391 | config->get_next_block = skb_ts_get_next_block; |
2392 | config->finish = skb_ts_finish; |
2393 | |
2394 | skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); |
2395 | |
2396 | ret = textsearch_find(config, state); |
2397 | return (ret <= to - from ? ret : UINT_MAX); |
2398 | } |
2399 | EXPORT_SYMBOL(skb_find_text); |
2400 | |
2401 | /** |
2402 | * skb_append_datato_frags: - append the user data to a skb |
2403 | * @sk: sock structure |
2404 | * @skb: skb structure to be appened with user data. |
2405 | * @getfrag: call back function to be used for getting the user data |
2406 | * @from: pointer to user message iov |
2407 | * @length: length of the iov message |
2408 | * |
2409 | * Description: This procedure append the user data in the fragment part |
2410 | * of the skb if any page alloc fails user this procedure returns -ENOMEM |
2411 | */ |
2412 | int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, |
2413 | int (*getfrag)(void *from, char *to, int offset, |
2414 | int len, int odd, struct sk_buff *skb), |
2415 | void *from, int length) |
2416 | { |
2417 | int frg_cnt = 0; |
2418 | skb_frag_t *frag = NULL; |
2419 | struct page *page = NULL; |
2420 | int copy, left; |
2421 | int offset = 0; |
2422 | int ret; |
2423 | |
2424 | do { |
2425 | /* Return error if we don't have space for new frag */ |
2426 | frg_cnt = skb_shinfo(skb)->nr_frags; |
2427 | if (frg_cnt >= MAX_SKB_FRAGS) |
2428 | return -EFAULT; |
2429 | |
2430 | /* allocate a new page for next frag */ |
2431 | page = alloc_pages(sk->sk_allocation, 0); |
2432 | |
2433 | /* If alloc_page fails just return failure and caller will |
2434 | * free previous allocated pages by doing kfree_skb() |
2435 | */ |
2436 | if (page == NULL) |
2437 | return -ENOMEM; |
2438 | |
2439 | /* initialize the next frag */ |
2440 | sk->sk_sndmsg_page = page; |
2441 | sk->sk_sndmsg_off = 0; |
2442 | skb_fill_page_desc(skb, frg_cnt, page, 0, 0); |
2443 | skb->truesize += PAGE_SIZE; |
2444 | atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); |
2445 | |
2446 | /* get the new initialized frag */ |
2447 | frg_cnt = skb_shinfo(skb)->nr_frags; |
2448 | frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; |
2449 | |
2450 | /* copy the user data to page */ |
2451 | left = PAGE_SIZE - frag->page_offset; |
2452 | copy = (length > left)? left : length; |
2453 | |
2454 | ret = getfrag(from, (page_address(frag->page) + |
2455 | frag->page_offset + frag->size), |
2456 | offset, copy, 0, skb); |
2457 | if (ret < 0) |
2458 | return -EFAULT; |
2459 | |
2460 | /* copy was successful so update the size parameters */ |
2461 | sk->sk_sndmsg_off += copy; |
2462 | frag->size += copy; |
2463 | skb->len += copy; |
2464 | skb->data_len += copy; |
2465 | offset += copy; |
2466 | length -= copy; |
2467 | |
2468 | } while (length > 0); |
2469 | |
2470 | return 0; |
2471 | } |
2472 | EXPORT_SYMBOL(skb_append_datato_frags); |
2473 | |
2474 | /** |
2475 | * skb_pull_rcsum - pull skb and update receive checksum |
2476 | * @skb: buffer to update |
2477 | * @len: length of data pulled |
2478 | * |
2479 | * This function performs an skb_pull on the packet and updates |
2480 | * the CHECKSUM_COMPLETE checksum. It should be used on |
2481 | * receive path processing instead of skb_pull unless you know |
2482 | * that the checksum difference is zero (e.g., a valid IP header) |
2483 | * or you are setting ip_summed to CHECKSUM_NONE. |
2484 | */ |
2485 | unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) |
2486 | { |
2487 | BUG_ON(len > skb->len); |
2488 | skb->len -= len; |
2489 | BUG_ON(skb->len < skb->data_len); |
2490 | skb_postpull_rcsum(skb, skb->data, len); |
2491 | return skb->data += len; |
2492 | } |
2493 | |
2494 | EXPORT_SYMBOL_GPL(skb_pull_rcsum); |
2495 | |
2496 | /** |
2497 | * skb_segment - Perform protocol segmentation on skb. |
2498 | * @skb: buffer to segment |
2499 | * @features: features for the output path (see dev->features) |
2500 | * |
2501 | * This function performs segmentation on the given skb. It returns |
2502 | * a pointer to the first in a list of new skbs for the segments. |
2503 | * In case of error it returns ERR_PTR(err). |
2504 | */ |
2505 | struct sk_buff *skb_segment(struct sk_buff *skb, int features) |
2506 | { |
2507 | struct sk_buff *segs = NULL; |
2508 | struct sk_buff *tail = NULL; |
2509 | struct sk_buff *fskb = skb_shinfo(skb)->frag_list; |
2510 | unsigned int mss = skb_shinfo(skb)->gso_size; |
2511 | unsigned int doffset = skb->data - skb_mac_header(skb); |
2512 | unsigned int offset = doffset; |
2513 | unsigned int headroom; |
2514 | unsigned int len; |
2515 | int sg = features & NETIF_F_SG; |
2516 | int nfrags = skb_shinfo(skb)->nr_frags; |
2517 | int err = -ENOMEM; |
2518 | int i = 0; |
2519 | int pos; |
2520 | |
2521 | __skb_push(skb, doffset); |
2522 | headroom = skb_headroom(skb); |
2523 | pos = skb_headlen(skb); |
2524 | |
2525 | do { |
2526 | struct sk_buff *nskb; |
2527 | skb_frag_t *frag; |
2528 | int hsize; |
2529 | int size; |
2530 | |
2531 | len = skb->len - offset; |
2532 | if (len > mss) |
2533 | len = mss; |
2534 | |
2535 | hsize = skb_headlen(skb) - offset; |
2536 | if (hsize < 0) |
2537 | hsize = 0; |
2538 | if (hsize > len || !sg) |
2539 | hsize = len; |
2540 | |
2541 | if (!hsize && i >= nfrags) { |
2542 | BUG_ON(fskb->len != len); |
2543 | |
2544 | pos += len; |
2545 | nskb = skb_clone(fskb, GFP_ATOMIC); |
2546 | fskb = fskb->next; |
2547 | |
2548 | if (unlikely(!nskb)) |
2549 | goto err; |
2550 | |
2551 | hsize = skb_end_pointer(nskb) - nskb->head; |
2552 | if (skb_cow_head(nskb, doffset + headroom)) { |
2553 | kfree_skb(nskb); |
2554 | goto err; |
2555 | } |
2556 | |
2557 | nskb->truesize += skb_end_pointer(nskb) - nskb->head - |
2558 | hsize; |
2559 | skb_release_head_state(nskb); |
2560 | __skb_push(nskb, doffset); |
2561 | } else { |
2562 | nskb = alloc_skb(hsize + doffset + headroom, |
2563 | GFP_ATOMIC); |
2564 | |
2565 | if (unlikely(!nskb)) |
2566 | goto err; |
2567 | |
2568 | skb_reserve(nskb, headroom); |
2569 | __skb_put(nskb, doffset); |
2570 | } |
2571 | |
2572 | if (segs) |
2573 | tail->next = nskb; |
2574 | else |
2575 | segs = nskb; |
2576 | tail = nskb; |
2577 | |
2578 | __copy_skb_header(nskb, skb); |
2579 | nskb->mac_len = skb->mac_len; |
2580 | |
2581 | skb_reset_mac_header(nskb); |
2582 | skb_set_network_header(nskb, skb->mac_len); |
2583 | nskb->transport_header = (nskb->network_header + |
2584 | skb_network_header_len(skb)); |
2585 | skb_copy_from_linear_data(skb, nskb->data, doffset); |
2586 | |
2587 | if (fskb != skb_shinfo(skb)->frag_list) |
2588 | continue; |
2589 | |
2590 | if (!sg) { |
2591 | nskb->ip_summed = CHECKSUM_NONE; |
2592 | nskb->csum = skb_copy_and_csum_bits(skb, offset, |
2593 | skb_put(nskb, len), |
2594 | len, 0); |
2595 | continue; |
2596 | } |
2597 | |
2598 | frag = skb_shinfo(nskb)->frags; |
2599 | |
2600 | skb_copy_from_linear_data_offset(skb, offset, |
2601 | skb_put(nskb, hsize), hsize); |
2602 | |
2603 | while (pos < offset + len && i < nfrags) { |
2604 | *frag = skb_shinfo(skb)->frags[i]; |
2605 | get_page(frag->page); |
2606 | size = frag->size; |
2607 | |
2608 | if (pos < offset) { |
2609 | frag->page_offset += offset - pos; |
2610 | frag->size -= offset - pos; |
2611 | } |
2612 | |
2613 | skb_shinfo(nskb)->nr_frags++; |
2614 | |
2615 | if (pos + size <= offset + len) { |
2616 | i++; |
2617 | pos += size; |
2618 | } else { |
2619 | frag->size -= pos + size - (offset + len); |
2620 | goto skip_fraglist; |
2621 | } |
2622 | |
2623 | frag++; |
2624 | } |
2625 | |
2626 | if (pos < offset + len) { |
2627 | struct sk_buff *fskb2 = fskb; |
2628 | |
2629 | BUG_ON(pos + fskb->len != offset + len); |
2630 | |
2631 | pos += fskb->len; |
2632 | fskb = fskb->next; |
2633 | |
2634 | if (fskb2->next) { |
2635 | fskb2 = skb_clone(fskb2, GFP_ATOMIC); |
2636 | if (!fskb2) |
2637 | goto err; |
2638 | } else |
2639 | skb_get(fskb2); |
2640 | |
2641 | SKB_FRAG_ASSERT(nskb); |
2642 | skb_shinfo(nskb)->frag_list = fskb2; |
2643 | } |
2644 | |
2645 | skip_fraglist: |
2646 | nskb->data_len = len - hsize; |
2647 | nskb->len += nskb->data_len; |
2648 | nskb->truesize += nskb->data_len; |
2649 | } while ((offset += len) < skb->len); |
2650 | |
2651 | return segs; |
2652 | |
2653 | err: |
2654 | while ((skb = segs)) { |
2655 | segs = skb->next; |
2656 | kfree_skb(skb); |
2657 | } |
2658 | return ERR_PTR(err); |
2659 | } |
2660 | EXPORT_SYMBOL_GPL(skb_segment); |
2661 | |
2662 | int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) |
2663 | { |
2664 | struct sk_buff *p = *head; |
2665 | struct sk_buff *nskb; |
2666 | struct skb_shared_info *skbinfo = skb_shinfo(skb); |
2667 | struct skb_shared_info *pinfo = skb_shinfo(p); |
2668 | unsigned int headroom; |
2669 | unsigned int len = skb_gro_len(skb); |
2670 | unsigned int offset = skb_gro_offset(skb); |
2671 | unsigned int headlen = skb_headlen(skb); |
2672 | |
2673 | if (p->len + len >= 65536) |
2674 | return -E2BIG; |
2675 | |
2676 | if (pinfo->frag_list) |
2677 | goto merge; |
2678 | else if (headlen <= offset) { |
2679 | skb_frag_t *frag; |
2680 | skb_frag_t *frag2; |
2681 | int i = skbinfo->nr_frags; |
2682 | int nr_frags = pinfo->nr_frags + i; |
2683 | |
2684 | offset -= headlen; |
2685 | |
2686 | if (nr_frags > MAX_SKB_FRAGS) |
2687 | return -E2BIG; |
2688 | |
2689 | pinfo->nr_frags = nr_frags; |
2690 | skbinfo->nr_frags = 0; |
2691 | |
2692 | frag = pinfo->frags + nr_frags; |
2693 | frag2 = skbinfo->frags + i; |
2694 | do { |
2695 | *--frag = *--frag2; |
2696 | } while (--i); |
2697 | |
2698 | frag->page_offset += offset; |
2699 | frag->size -= offset; |
2700 | |
2701 | skb->truesize -= skb->data_len; |
2702 | skb->len -= skb->data_len; |
2703 | skb->data_len = 0; |
2704 | |
2705 | NAPI_GRO_CB(skb)->free = 1; |
2706 | goto done; |
2707 | } else if (skb_gro_len(p) != pinfo->gso_size) |
2708 | return -E2BIG; |
2709 | |
2710 | headroom = skb_headroom(p); |
2711 | nskb = netdev_alloc_skb(p->dev, headroom + skb_gro_offset(p)); |
2712 | if (unlikely(!nskb)) |
2713 | return -ENOMEM; |
2714 | |
2715 | __copy_skb_header(nskb, p); |
2716 | nskb->mac_len = p->mac_len; |
2717 | |
2718 | skb_reserve(nskb, headroom); |
2719 | __skb_put(nskb, skb_gro_offset(p)); |
2720 | |
2721 | skb_set_mac_header(nskb, skb_mac_header(p) - p->data); |
2722 | skb_set_network_header(nskb, skb_network_offset(p)); |
2723 | skb_set_transport_header(nskb, skb_transport_offset(p)); |
2724 | |
2725 | __skb_pull(p, skb_gro_offset(p)); |
2726 | memcpy(skb_mac_header(nskb), skb_mac_header(p), |
2727 | p->data - skb_mac_header(p)); |
2728 | |
2729 | *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p); |
2730 | skb_shinfo(nskb)->frag_list = p; |
2731 | skb_shinfo(nskb)->gso_size = pinfo->gso_size; |
2732 | skb_header_release(p); |
2733 | nskb->prev = p; |
2734 | |
2735 | nskb->data_len += p->len; |
2736 | nskb->truesize += p->len; |
2737 | nskb->len += p->len; |
2738 | |
2739 | *head = nskb; |
2740 | nskb->next = p->next; |
2741 | p->next = NULL; |
2742 | |
2743 | p = nskb; |
2744 | |
2745 | merge: |
2746 | if (offset > headlen) { |
2747 | skbinfo->frags[0].page_offset += offset - headlen; |
2748 | skbinfo->frags[0].size -= offset - headlen; |
2749 | offset = headlen; |
2750 | } |
2751 | |
2752 | __skb_pull(skb, offset); |
2753 | |
2754 | p->prev->next = skb; |
2755 | p->prev = skb; |
2756 | skb_header_release(skb); |
2757 | |
2758 | done: |
2759 | NAPI_GRO_CB(p)->count++; |
2760 | p->data_len += len; |
2761 | p->truesize += len; |
2762 | p->len += len; |
2763 | |
2764 | NAPI_GRO_CB(skb)->same_flow = 1; |
2765 | return 0; |
2766 | } |
2767 | EXPORT_SYMBOL_GPL(skb_gro_receive); |
2768 | |
2769 | void __init skb_init(void) |
2770 | { |
2771 | skbuff_head_cache = kmem_cache_create("skbuff_head_cache", |
2772 | sizeof(struct sk_buff), |
2773 | 0, |
2774 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, |
2775 | NULL); |
2776 | skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", |
2777 | (2*sizeof(struct sk_buff)) + |
2778 | sizeof(atomic_t), |
2779 | 0, |
2780 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, |
2781 | NULL); |
2782 | } |
2783 | |
2784 | /** |
2785 | * skb_to_sgvec - Fill a scatter-gather list from a socket buffer |
2786 | * @skb: Socket buffer containing the buffers to be mapped |
2787 | * @sg: The scatter-gather list to map into |
2788 | * @offset: The offset into the buffer's contents to start mapping |
2789 | * @len: Length of buffer space to be mapped |
2790 | * |
2791 | * Fill the specified scatter-gather list with mappings/pointers into a |
2792 | * region of the buffer space attached to a socket buffer. |
2793 | */ |
2794 | static int |
2795 | __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) |
2796 | { |
2797 | int start = skb_headlen(skb); |
2798 | int i, copy = start - offset; |
2799 | struct sk_buff *frag_iter; |
2800 | int elt = 0; |
2801 | |
2802 | if (copy > 0) { |
2803 | if (copy > len) |
2804 | copy = len; |
2805 | sg_set_buf(sg, skb->data + offset, copy); |
2806 | elt++; |
2807 | if ((len -= copy) == 0) |
2808 | return elt; |
2809 | offset += copy; |
2810 | } |
2811 | |
2812 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
2813 | int end; |
2814 | |
2815 | WARN_ON(start > offset + len); |
2816 | |
2817 | end = start + skb_shinfo(skb)->frags[i].size; |
2818 | if ((copy = end - offset) > 0) { |
2819 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
2820 | |
2821 | if (copy > len) |
2822 | copy = len; |
2823 | sg_set_page(&sg[elt], frag->page, copy, |
2824 | frag->page_offset+offset-start); |
2825 | elt++; |
2826 | if (!(len -= copy)) |
2827 | return elt; |
2828 | offset += copy; |
2829 | } |
2830 | start = end; |
2831 | } |
2832 | |
2833 | skb_walk_frags(skb, frag_iter) { |
2834 | int end; |
2835 | |
2836 | WARN_ON(start > offset + len); |
2837 | |
2838 | end = start + frag_iter->len; |
2839 | if ((copy = end - offset) > 0) { |
2840 | if (copy > len) |
2841 | copy = len; |
2842 | elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start, |
2843 | copy); |
2844 | if ((len -= copy) == 0) |
2845 | return elt; |
2846 | offset += copy; |
2847 | } |
2848 | start = end; |
2849 | } |
2850 | BUG_ON(len); |
2851 | return elt; |
2852 | } |
2853 | |
2854 | int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) |
2855 | { |
2856 | int nsg = __skb_to_sgvec(skb, sg, offset, len); |
2857 | |
2858 | sg_mark_end(&sg[nsg - 1]); |
2859 | |
2860 | return nsg; |
2861 | } |
2862 | EXPORT_SYMBOL_GPL(skb_to_sgvec); |
2863 | |
2864 | /** |
2865 | * skb_cow_data - Check that a socket buffer's data buffers are writable |
2866 | * @skb: The socket buffer to check. |
2867 | * @tailbits: Amount of trailing space to be added |
2868 | * @trailer: Returned pointer to the skb where the @tailbits space begins |
2869 | * |
2870 | * Make sure that the data buffers attached to a socket buffer are |
2871 | * writable. If they are not, private copies are made of the data buffers |
2872 | * and the socket buffer is set to use these instead. |
2873 | * |
2874 | * If @tailbits is given, make sure that there is space to write @tailbits |
2875 | * bytes of data beyond current end of socket buffer. @trailer will be |
2876 | * set to point to the skb in which this space begins. |
2877 | * |
2878 | * The number of scatterlist elements required to completely map the |
2879 | * COW'd and extended socket buffer will be returned. |
2880 | */ |
2881 | int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) |
2882 | { |
2883 | int copyflag; |
2884 | int elt; |
2885 | struct sk_buff *skb1, **skb_p; |
2886 | |
2887 | /* If skb is cloned or its head is paged, reallocate |
2888 | * head pulling out all the pages (pages are considered not writable |
2889 | * at the moment even if they are anonymous). |
2890 | */ |
2891 | if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) && |
2892 | __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL) |
2893 | return -ENOMEM; |
2894 | |
2895 | /* Easy case. Most of packets will go this way. */ |
2896 | if (!skb_has_frags(skb)) { |
2897 | /* A little of trouble, not enough of space for trailer. |
2898 | * This should not happen, when stack is tuned to generate |
2899 | * good frames. OK, on miss we reallocate and reserve even more |
2900 | * space, 128 bytes is fair. */ |
2901 | |
2902 | if (skb_tailroom(skb) < tailbits && |
2903 | pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC)) |
2904 | return -ENOMEM; |
2905 | |
2906 | /* Voila! */ |
2907 | *trailer = skb; |
2908 | return 1; |
2909 | } |
2910 | |
2911 | /* Misery. We are in troubles, going to mincer fragments... */ |
2912 | |
2913 | elt = 1; |
2914 | skb_p = &skb_shinfo(skb)->frag_list; |
2915 | copyflag = 0; |
2916 | |
2917 | while ((skb1 = *skb_p) != NULL) { |
2918 | int ntail = 0; |
2919 | |
2920 | /* The fragment is partially pulled by someone, |
2921 | * this can happen on input. Copy it and everything |
2922 | * after it. */ |
2923 | |
2924 | if (skb_shared(skb1)) |
2925 | copyflag = 1; |
2926 | |
2927 | /* If the skb is the last, worry about trailer. */ |
2928 | |
2929 | if (skb1->next == NULL && tailbits) { |
2930 | if (skb_shinfo(skb1)->nr_frags || |
2931 | skb_has_frags(skb1) || |
2932 | skb_tailroom(skb1) < tailbits) |
2933 | ntail = tailbits + 128; |
2934 | } |
2935 | |
2936 | if (copyflag || |
2937 | skb_cloned(skb1) || |
2938 | ntail || |
2939 | skb_shinfo(skb1)->nr_frags || |
2940 | skb_has_frags(skb1)) { |
2941 | struct sk_buff *skb2; |
2942 | |
2943 | /* Fuck, we are miserable poor guys... */ |
2944 | if (ntail == 0) |
2945 | skb2 = skb_copy(skb1, GFP_ATOMIC); |
2946 | else |
2947 | skb2 = skb_copy_expand(skb1, |
2948 | skb_headroom(skb1), |
2949 | ntail, |
2950 | GFP_ATOMIC); |
2951 | if (unlikely(skb2 == NULL)) |
2952 | return -ENOMEM; |
2953 | |
2954 | if (skb1->sk) |
2955 | skb_set_owner_w(skb2, skb1->sk); |
2956 | |
2957 | /* Looking around. Are we still alive? |
2958 | * OK, link new skb, drop old one */ |
2959 | |
2960 | skb2->next = skb1->next; |
2961 | *skb_p = skb2; |
2962 | kfree_skb(skb1); |
2963 | skb1 = skb2; |
2964 | } |
2965 | elt++; |
2966 | *trailer = skb1; |
2967 | skb_p = &skb1->next; |
2968 | } |
2969 | |
2970 | return elt; |
2971 | } |
2972 | EXPORT_SYMBOL_GPL(skb_cow_data); |
2973 | |
2974 | void skb_tstamp_tx(struct sk_buff *orig_skb, |
2975 | struct skb_shared_hwtstamps *hwtstamps) |
2976 | { |
2977 | struct sock *sk = orig_skb->sk; |
2978 | struct sock_exterr_skb *serr; |
2979 | struct sk_buff *skb; |
2980 | int err; |
2981 | |
2982 | if (!sk) |
2983 | return; |
2984 | |
2985 | skb = skb_clone(orig_skb, GFP_ATOMIC); |
2986 | if (!skb) |
2987 | return; |
2988 | |
2989 | if (hwtstamps) { |
2990 | *skb_hwtstamps(skb) = |
2991 | *hwtstamps; |
2992 | } else { |
2993 | /* |
2994 | * no hardware time stamps available, |
2995 | * so keep the skb_shared_tx and only |
2996 | * store software time stamp |
2997 | */ |
2998 | skb->tstamp = ktime_get_real(); |
2999 | } |
3000 | |
3001 | serr = SKB_EXT_ERR(skb); |
3002 | memset(serr, 0, sizeof(*serr)); |
3003 | serr->ee.ee_errno = ENOMSG; |
3004 | serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING; |
3005 | err = sock_queue_err_skb(sk, skb); |
3006 | if (err) |
3007 | kfree_skb(skb); |
3008 | } |
3009 | EXPORT_SYMBOL_GPL(skb_tstamp_tx); |
3010 | |
3011 | |
3012 | /** |
3013 | * skb_partial_csum_set - set up and verify partial csum values for packet |
3014 | * @skb: the skb to set |
3015 | * @start: the number of bytes after skb->data to start checksumming. |
3016 | * @off: the offset from start to place the checksum. |
3017 | * |
3018 | * For untrusted partially-checksummed packets, we need to make sure the values |
3019 | * for skb->csum_start and skb->csum_offset are valid so we don't oops. |
3020 | * |
3021 | * This function checks and sets those values and skb->ip_summed: if this |
3022 | * returns false you should drop the packet. |
3023 | */ |
3024 | bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off) |
3025 | { |
3026 | if (unlikely(start > skb_headlen(skb)) || |
3027 | unlikely((int)start + off > skb_headlen(skb) - 2)) { |
3028 | if (net_ratelimit()) |
3029 | printk(KERN_WARNING |
3030 | "bad partial csum: csum=%u/%u len=%u\n", |
3031 | start, off, skb_headlen(skb)); |
3032 | return false; |
3033 | } |
3034 | skb->ip_summed = CHECKSUM_PARTIAL; |
3035 | skb->csum_start = skb_headroom(skb) + start; |
3036 | skb->csum_offset = off; |
3037 | return true; |
3038 | } |
3039 | EXPORT_SYMBOL_GPL(skb_partial_csum_set); |
3040 | |
3041 | void __skb_warn_lro_forwarding(const struct sk_buff *skb) |
3042 | { |
3043 | if (net_ratelimit()) |
3044 | pr_warning("%s: received packets cannot be forwarded" |
3045 | " while LRO is enabled\n", skb->dev->name); |
3046 | } |
3047 | EXPORT_SYMBOL(__skb_warn_lro_forwarding); |
3048 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9