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1da177e4 LT |
1 | /* |
2 | * Definitions for the 'struct sk_buff' memory handlers. | |
3 | * | |
4 | * Authors: | |
5 | * Alan Cox, <gw4pts@gw4pts.ampr.org> | |
6 | * Florian La Roche, <rzsfl@rz.uni-sb.de> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
12 | */ | |
13 | ||
14 | #ifndef _LINUX_SKBUFF_H | |
15 | #define _LINUX_SKBUFF_H | |
16 | ||
17 | #include <linux/config.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/compiler.h> | |
20 | #include <linux/time.h> | |
21 | #include <linux/cache.h> | |
22 | ||
23 | #include <asm/atomic.h> | |
24 | #include <asm/types.h> | |
25 | #include <linux/spinlock.h> | |
26 | #include <linux/mm.h> | |
27 | #include <linux/highmem.h> | |
28 | #include <linux/poll.h> | |
29 | #include <linux/net.h> | |
3fc7e8a6 | 30 | #include <linux/textsearch.h> |
1da177e4 LT |
31 | #include <net/checksum.h> |
32 | ||
33 | #define HAVE_ALLOC_SKB /* For the drivers to know */ | |
34 | #define HAVE_ALIGNABLE_SKB /* Ditto 8) */ | |
35 | #define SLAB_SKB /* Slabified skbuffs */ | |
36 | ||
37 | #define CHECKSUM_NONE 0 | |
38 | #define CHECKSUM_HW 1 | |
39 | #define CHECKSUM_UNNECESSARY 2 | |
40 | ||
41 | #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \ | |
42 | ~(SMP_CACHE_BYTES - 1)) | |
43 | #define SKB_MAX_ORDER(X, ORDER) (((PAGE_SIZE << (ORDER)) - (X) - \ | |
44 | sizeof(struct skb_shared_info)) & \ | |
45 | ~(SMP_CACHE_BYTES - 1)) | |
46 | #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0)) | |
47 | #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2)) | |
48 | ||
49 | /* A. Checksumming of received packets by device. | |
50 | * | |
51 | * NONE: device failed to checksum this packet. | |
52 | * skb->csum is undefined. | |
53 | * | |
54 | * UNNECESSARY: device parsed packet and wouldbe verified checksum. | |
55 | * skb->csum is undefined. | |
56 | * It is bad option, but, unfortunately, many of vendors do this. | |
57 | * Apparently with secret goal to sell you new device, when you | |
58 | * will add new protocol to your host. F.e. IPv6. 8) | |
59 | * | |
60 | * HW: the most generic way. Device supplied checksum of _all_ | |
61 | * the packet as seen by netif_rx in skb->csum. | |
62 | * NOTE: Even if device supports only some protocols, but | |
63 | * is able to produce some skb->csum, it MUST use HW, | |
64 | * not UNNECESSARY. | |
65 | * | |
66 | * B. Checksumming on output. | |
67 | * | |
68 | * NONE: skb is checksummed by protocol or csum is not required. | |
69 | * | |
70 | * HW: device is required to csum packet as seen by hard_start_xmit | |
71 | * from skb->h.raw to the end and to record the checksum | |
72 | * at skb->h.raw+skb->csum. | |
73 | * | |
74 | * Device must show its capabilities in dev->features, set | |
75 | * at device setup time. | |
76 | * NETIF_F_HW_CSUM - it is clever device, it is able to checksum | |
77 | * everything. | |
78 | * NETIF_F_NO_CSUM - loopback or reliable single hop media. | |
79 | * NETIF_F_IP_CSUM - device is dumb. It is able to csum only | |
80 | * TCP/UDP over IPv4. Sigh. Vendors like this | |
81 | * way by an unknown reason. Though, see comment above | |
82 | * about CHECKSUM_UNNECESSARY. 8) | |
83 | * | |
84 | * Any questions? No questions, good. --ANK | |
85 | */ | |
86 | ||
1da177e4 LT |
87 | struct net_device; |
88 | ||
89 | #ifdef CONFIG_NETFILTER | |
90 | struct nf_conntrack { | |
91 | atomic_t use; | |
92 | void (*destroy)(struct nf_conntrack *); | |
93 | }; | |
94 | ||
95 | #ifdef CONFIG_BRIDGE_NETFILTER | |
96 | struct nf_bridge_info { | |
97 | atomic_t use; | |
98 | struct net_device *physindev; | |
99 | struct net_device *physoutdev; | |
100 | #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE) | |
101 | struct net_device *netoutdev; | |
102 | #endif | |
103 | unsigned int mask; | |
104 | unsigned long data[32 / sizeof(unsigned long)]; | |
105 | }; | |
106 | #endif | |
107 | ||
108 | #endif | |
109 | ||
110 | struct sk_buff_head { | |
111 | /* These two members must be first. */ | |
112 | struct sk_buff *next; | |
113 | struct sk_buff *prev; | |
114 | ||
115 | __u32 qlen; | |
116 | spinlock_t lock; | |
117 | }; | |
118 | ||
119 | struct sk_buff; | |
120 | ||
121 | /* To allow 64K frame to be packed as single skb without frag_list */ | |
122 | #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2) | |
123 | ||
124 | typedef struct skb_frag_struct skb_frag_t; | |
125 | ||
126 | struct skb_frag_struct { | |
127 | struct page *page; | |
128 | __u16 page_offset; | |
129 | __u16 size; | |
130 | }; | |
131 | ||
132 | /* This data is invariant across clones and lives at | |
133 | * the end of the header data, ie. at skb->end. | |
134 | */ | |
135 | struct skb_shared_info { | |
136 | atomic_t dataref; | |
137 | unsigned int nr_frags; | |
138 | unsigned short tso_size; | |
139 | unsigned short tso_segs; | |
140 | struct sk_buff *frag_list; | |
141 | skb_frag_t frags[MAX_SKB_FRAGS]; | |
142 | }; | |
143 | ||
144 | /* We divide dataref into two halves. The higher 16 bits hold references | |
145 | * to the payload part of skb->data. The lower 16 bits hold references to | |
146 | * the entire skb->data. It is up to the users of the skb to agree on | |
147 | * where the payload starts. | |
148 | * | |
149 | * All users must obey the rule that the skb->data reference count must be | |
150 | * greater than or equal to the payload reference count. | |
151 | * | |
152 | * Holding a reference to the payload part means that the user does not | |
153 | * care about modifications to the header part of skb->data. | |
154 | */ | |
155 | #define SKB_DATAREF_SHIFT 16 | |
156 | #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1) | |
157 | ||
a61bbcf2 PM |
158 | struct skb_timeval { |
159 | u32 off_sec; | |
160 | u32 off_usec; | |
161 | }; | |
162 | ||
d179cd12 DM |
163 | |
164 | enum { | |
165 | SKB_FCLONE_UNAVAILABLE, | |
166 | SKB_FCLONE_ORIG, | |
167 | SKB_FCLONE_CLONE, | |
168 | }; | |
169 | ||
1da177e4 LT |
170 | /** |
171 | * struct sk_buff - socket buffer | |
172 | * @next: Next buffer in list | |
173 | * @prev: Previous buffer in list | |
1da177e4 | 174 | * @sk: Socket we are owned by |
325ed823 | 175 | * @tstamp: Time we arrived |
1da177e4 LT |
176 | * @dev: Device we arrived on/are leaving by |
177 | * @input_dev: Device we arrived on | |
1da177e4 LT |
178 | * @h: Transport layer header |
179 | * @nh: Network layer header | |
180 | * @mac: Link layer header | |
67be2dd1 MW |
181 | * @dst: destination entry |
182 | * @sp: the security path, used for xfrm | |
1da177e4 LT |
183 | * @cb: Control buffer. Free for use by every layer. Put private vars here |
184 | * @len: Length of actual data | |
185 | * @data_len: Data length | |
186 | * @mac_len: Length of link layer header | |
187 | * @csum: Checksum | |
67be2dd1 | 188 | * @local_df: allow local fragmentation |
1da177e4 LT |
189 | * @cloned: Head may be cloned (check refcnt to be sure) |
190 | * @nohdr: Payload reference only, must not modify header | |
191 | * @pkt_type: Packet class | |
c83c2486 | 192 | * @fclone: skbuff clone status |
1da177e4 LT |
193 | * @ip_summed: Driver fed us an IP checksum |
194 | * @priority: Packet queueing priority | |
195 | * @users: User count - see {datagram,tcp}.c | |
196 | * @protocol: Packet protocol from driver | |
1da177e4 LT |
197 | * @truesize: Buffer size |
198 | * @head: Head of buffer | |
199 | * @data: Data head pointer | |
200 | * @tail: Tail pointer | |
201 | * @end: End pointer | |
202 | * @destructor: Destruct function | |
203 | * @nfmark: Can be used for communication between hooks | |
1da177e4 | 204 | * @nfct: Associated connection, if any |
c83c2486 | 205 | * @ipvs_property: skbuff is owned by ipvs |
1da177e4 | 206 | * @nfctinfo: Relationship of this skb to the connection |
1da177e4 | 207 | * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c |
1da177e4 LT |
208 | * @tc_index: Traffic control index |
209 | * @tc_verd: traffic control verdict | |
1da177e4 LT |
210 | */ |
211 | ||
212 | struct sk_buff { | |
213 | /* These two members must be first. */ | |
214 | struct sk_buff *next; | |
215 | struct sk_buff *prev; | |
216 | ||
1da177e4 | 217 | struct sock *sk; |
a61bbcf2 | 218 | struct skb_timeval tstamp; |
1da177e4 LT |
219 | struct net_device *dev; |
220 | struct net_device *input_dev; | |
1da177e4 LT |
221 | |
222 | union { | |
223 | struct tcphdr *th; | |
224 | struct udphdr *uh; | |
225 | struct icmphdr *icmph; | |
226 | struct igmphdr *igmph; | |
227 | struct iphdr *ipiph; | |
228 | struct ipv6hdr *ipv6h; | |
229 | unsigned char *raw; | |
230 | } h; | |
231 | ||
232 | union { | |
233 | struct iphdr *iph; | |
234 | struct ipv6hdr *ipv6h; | |
235 | struct arphdr *arph; | |
236 | unsigned char *raw; | |
237 | } nh; | |
238 | ||
239 | union { | |
240 | unsigned char *raw; | |
241 | } mac; | |
242 | ||
243 | struct dst_entry *dst; | |
244 | struct sec_path *sp; | |
245 | ||
246 | /* | |
247 | * This is the control buffer. It is free to use for every | |
248 | * layer. Please put your private variables there. If you | |
249 | * want to keep them across layers you have to do a skb_clone() | |
250 | * first. This is owned by whoever has the skb queued ATM. | |
251 | */ | |
252 | char cb[40]; | |
253 | ||
254 | unsigned int len, | |
255 | data_len, | |
256 | mac_len, | |
257 | csum; | |
1da177e4 | 258 | __u32 priority; |
1cbb3380 TG |
259 | __u8 local_df:1, |
260 | cloned:1, | |
261 | ip_summed:2, | |
6869c4d8 HW |
262 | nohdr:1, |
263 | nfctinfo:3; | |
d179cd12 DM |
264 | __u8 pkt_type:3, |
265 | fclone:2; | |
a0d3bea3 | 266 | __be16 protocol; |
1da177e4 LT |
267 | |
268 | void (*destructor)(struct sk_buff *skb); | |
269 | #ifdef CONFIG_NETFILTER | |
bf3a46aa | 270 | __u32 nfmark; |
1da177e4 | 271 | struct nf_conntrack *nfct; |
6869c4d8 HW |
272 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) |
273 | __u8 ipvs_property:1; | |
274 | #endif | |
1da177e4 LT |
275 | #ifdef CONFIG_BRIDGE_NETFILTER |
276 | struct nf_bridge_info *nf_bridge; | |
277 | #endif | |
278 | #endif /* CONFIG_NETFILTER */ | |
1da177e4 | 279 | #ifdef CONFIG_NET_SCHED |
b6b99eb5 | 280 | __u16 tc_index; /* traffic control index */ |
1da177e4 | 281 | #ifdef CONFIG_NET_CLS_ACT |
b6b99eb5 | 282 | __u16 tc_verd; /* traffic control verdict */ |
1da177e4 | 283 | #endif |
1da177e4 LT |
284 | #endif |
285 | ||
286 | ||
287 | /* These elements must be at the end, see alloc_skb() for details. */ | |
288 | unsigned int truesize; | |
289 | atomic_t users; | |
290 | unsigned char *head, | |
291 | *data, | |
292 | *tail, | |
293 | *end; | |
294 | }; | |
295 | ||
296 | #ifdef __KERNEL__ | |
297 | /* | |
298 | * Handling routines are only of interest to the kernel | |
299 | */ | |
300 | #include <linux/slab.h> | |
301 | ||
302 | #include <asm/system.h> | |
303 | ||
304 | extern void __kfree_skb(struct sk_buff *skb); | |
d179cd12 | 305 | extern struct sk_buff *__alloc_skb(unsigned int size, |
dd0fc66f | 306 | gfp_t priority, int fclone); |
d179cd12 | 307 | static inline struct sk_buff *alloc_skb(unsigned int size, |
dd0fc66f | 308 | gfp_t priority) |
d179cd12 DM |
309 | { |
310 | return __alloc_skb(size, priority, 0); | |
311 | } | |
312 | ||
313 | static inline struct sk_buff *alloc_skb_fclone(unsigned int size, | |
dd0fc66f | 314 | gfp_t priority) |
d179cd12 DM |
315 | { |
316 | return __alloc_skb(size, priority, 1); | |
317 | } | |
318 | ||
1da177e4 | 319 | extern struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp, |
86a76caf | 320 | unsigned int size, |
dd0fc66f | 321 | gfp_t priority); |
1da177e4 | 322 | extern void kfree_skbmem(struct sk_buff *skb); |
86a76caf | 323 | extern struct sk_buff *skb_clone(struct sk_buff *skb, |
dd0fc66f | 324 | gfp_t priority); |
86a76caf | 325 | extern struct sk_buff *skb_copy(const struct sk_buff *skb, |
dd0fc66f | 326 | gfp_t priority); |
86a76caf | 327 | extern struct sk_buff *pskb_copy(struct sk_buff *skb, |
dd0fc66f | 328 | gfp_t gfp_mask); |
1da177e4 | 329 | extern int pskb_expand_head(struct sk_buff *skb, |
86a76caf | 330 | int nhead, int ntail, |
dd0fc66f | 331 | gfp_t gfp_mask); |
1da177e4 LT |
332 | extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, |
333 | unsigned int headroom); | |
334 | extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb, | |
335 | int newheadroom, int newtailroom, | |
dd0fc66f | 336 | gfp_t priority); |
1da177e4 LT |
337 | extern struct sk_buff * skb_pad(struct sk_buff *skb, int pad); |
338 | #define dev_kfree_skb(a) kfree_skb(a) | |
339 | extern void skb_over_panic(struct sk_buff *skb, int len, | |
340 | void *here); | |
341 | extern void skb_under_panic(struct sk_buff *skb, int len, | |
342 | void *here); | |
343 | ||
677e90ed TG |
344 | struct skb_seq_state |
345 | { | |
346 | __u32 lower_offset; | |
347 | __u32 upper_offset; | |
348 | __u32 frag_idx; | |
349 | __u32 stepped_offset; | |
350 | struct sk_buff *root_skb; | |
351 | struct sk_buff *cur_skb; | |
352 | __u8 *frag_data; | |
353 | }; | |
354 | ||
355 | extern void skb_prepare_seq_read(struct sk_buff *skb, | |
356 | unsigned int from, unsigned int to, | |
357 | struct skb_seq_state *st); | |
358 | extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data, | |
359 | struct skb_seq_state *st); | |
360 | extern void skb_abort_seq_read(struct skb_seq_state *st); | |
361 | ||
3fc7e8a6 TG |
362 | extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, |
363 | unsigned int to, struct ts_config *config, | |
364 | struct ts_state *state); | |
365 | ||
1da177e4 LT |
366 | /* Internal */ |
367 | #define skb_shinfo(SKB) ((struct skb_shared_info *)((SKB)->end)) | |
368 | ||
369 | /** | |
370 | * skb_queue_empty - check if a queue is empty | |
371 | * @list: queue head | |
372 | * | |
373 | * Returns true if the queue is empty, false otherwise. | |
374 | */ | |
375 | static inline int skb_queue_empty(const struct sk_buff_head *list) | |
376 | { | |
377 | return list->next == (struct sk_buff *)list; | |
378 | } | |
379 | ||
380 | /** | |
381 | * skb_get - reference buffer | |
382 | * @skb: buffer to reference | |
383 | * | |
384 | * Makes another reference to a socket buffer and returns a pointer | |
385 | * to the buffer. | |
386 | */ | |
387 | static inline struct sk_buff *skb_get(struct sk_buff *skb) | |
388 | { | |
389 | atomic_inc(&skb->users); | |
390 | return skb; | |
391 | } | |
392 | ||
393 | /* | |
394 | * If users == 1, we are the only owner and are can avoid redundant | |
395 | * atomic change. | |
396 | */ | |
397 | ||
398 | /** | |
399 | * kfree_skb - free an sk_buff | |
400 | * @skb: buffer to free | |
401 | * | |
402 | * Drop a reference to the buffer and free it if the usage count has | |
403 | * hit zero. | |
404 | */ | |
405 | static inline void kfree_skb(struct sk_buff *skb) | |
406 | { | |
407 | if (likely(atomic_read(&skb->users) == 1)) | |
408 | smp_rmb(); | |
409 | else if (likely(!atomic_dec_and_test(&skb->users))) | |
410 | return; | |
411 | __kfree_skb(skb); | |
412 | } | |
413 | ||
414 | /** | |
415 | * skb_cloned - is the buffer a clone | |
416 | * @skb: buffer to check | |
417 | * | |
418 | * Returns true if the buffer was generated with skb_clone() and is | |
419 | * one of multiple shared copies of the buffer. Cloned buffers are | |
420 | * shared data so must not be written to under normal circumstances. | |
421 | */ | |
422 | static inline int skb_cloned(const struct sk_buff *skb) | |
423 | { | |
424 | return skb->cloned && | |
425 | (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1; | |
426 | } | |
427 | ||
428 | /** | |
429 | * skb_header_cloned - is the header a clone | |
430 | * @skb: buffer to check | |
431 | * | |
432 | * Returns true if modifying the header part of the buffer requires | |
433 | * the data to be copied. | |
434 | */ | |
435 | static inline int skb_header_cloned(const struct sk_buff *skb) | |
436 | { | |
437 | int dataref; | |
438 | ||
439 | if (!skb->cloned) | |
440 | return 0; | |
441 | ||
442 | dataref = atomic_read(&skb_shinfo(skb)->dataref); | |
443 | dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT); | |
444 | return dataref != 1; | |
445 | } | |
446 | ||
447 | /** | |
448 | * skb_header_release - release reference to header | |
449 | * @skb: buffer to operate on | |
450 | * | |
451 | * Drop a reference to the header part of the buffer. This is done | |
452 | * by acquiring a payload reference. You must not read from the header | |
453 | * part of skb->data after this. | |
454 | */ | |
455 | static inline void skb_header_release(struct sk_buff *skb) | |
456 | { | |
457 | BUG_ON(skb->nohdr); | |
458 | skb->nohdr = 1; | |
459 | atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref); | |
460 | } | |
461 | ||
462 | /** | |
463 | * skb_shared - is the buffer shared | |
464 | * @skb: buffer to check | |
465 | * | |
466 | * Returns true if more than one person has a reference to this | |
467 | * buffer. | |
468 | */ | |
469 | static inline int skb_shared(const struct sk_buff *skb) | |
470 | { | |
471 | return atomic_read(&skb->users) != 1; | |
472 | } | |
473 | ||
474 | /** | |
475 | * skb_share_check - check if buffer is shared and if so clone it | |
476 | * @skb: buffer to check | |
477 | * @pri: priority for memory allocation | |
478 | * | |
479 | * If the buffer is shared the buffer is cloned and the old copy | |
480 | * drops a reference. A new clone with a single reference is returned. | |
481 | * If the buffer is not shared the original buffer is returned. When | |
482 | * being called from interrupt status or with spinlocks held pri must | |
483 | * be GFP_ATOMIC. | |
484 | * | |
485 | * NULL is returned on a memory allocation failure. | |
486 | */ | |
86a76caf | 487 | static inline struct sk_buff *skb_share_check(struct sk_buff *skb, |
dd0fc66f | 488 | gfp_t pri) |
1da177e4 LT |
489 | { |
490 | might_sleep_if(pri & __GFP_WAIT); | |
491 | if (skb_shared(skb)) { | |
492 | struct sk_buff *nskb = skb_clone(skb, pri); | |
493 | kfree_skb(skb); | |
494 | skb = nskb; | |
495 | } | |
496 | return skb; | |
497 | } | |
498 | ||
499 | /* | |
500 | * Copy shared buffers into a new sk_buff. We effectively do COW on | |
501 | * packets to handle cases where we have a local reader and forward | |
502 | * and a couple of other messy ones. The normal one is tcpdumping | |
503 | * a packet thats being forwarded. | |
504 | */ | |
505 | ||
506 | /** | |
507 | * skb_unshare - make a copy of a shared buffer | |
508 | * @skb: buffer to check | |
509 | * @pri: priority for memory allocation | |
510 | * | |
511 | * If the socket buffer is a clone then this function creates a new | |
512 | * copy of the data, drops a reference count on the old copy and returns | |
513 | * the new copy with the reference count at 1. If the buffer is not a clone | |
514 | * the original buffer is returned. When called with a spinlock held or | |
515 | * from interrupt state @pri must be %GFP_ATOMIC | |
516 | * | |
517 | * %NULL is returned on a memory allocation failure. | |
518 | */ | |
e2bf521d | 519 | static inline struct sk_buff *skb_unshare(struct sk_buff *skb, |
dd0fc66f | 520 | gfp_t pri) |
1da177e4 LT |
521 | { |
522 | might_sleep_if(pri & __GFP_WAIT); | |
523 | if (skb_cloned(skb)) { | |
524 | struct sk_buff *nskb = skb_copy(skb, pri); | |
525 | kfree_skb(skb); /* Free our shared copy */ | |
526 | skb = nskb; | |
527 | } | |
528 | return skb; | |
529 | } | |
530 | ||
531 | /** | |
532 | * skb_peek | |
533 | * @list_: list to peek at | |
534 | * | |
535 | * Peek an &sk_buff. Unlike most other operations you _MUST_ | |
536 | * be careful with this one. A peek leaves the buffer on the | |
537 | * list and someone else may run off with it. You must hold | |
538 | * the appropriate locks or have a private queue to do this. | |
539 | * | |
540 | * Returns %NULL for an empty list or a pointer to the head element. | |
541 | * The reference count is not incremented and the reference is therefore | |
542 | * volatile. Use with caution. | |
543 | */ | |
544 | static inline struct sk_buff *skb_peek(struct sk_buff_head *list_) | |
545 | { | |
546 | struct sk_buff *list = ((struct sk_buff *)list_)->next; | |
547 | if (list == (struct sk_buff *)list_) | |
548 | list = NULL; | |
549 | return list; | |
550 | } | |
551 | ||
552 | /** | |
553 | * skb_peek_tail | |
554 | * @list_: list to peek at | |
555 | * | |
556 | * Peek an &sk_buff. Unlike most other operations you _MUST_ | |
557 | * be careful with this one. A peek leaves the buffer on the | |
558 | * list and someone else may run off with it. You must hold | |
559 | * the appropriate locks or have a private queue to do this. | |
560 | * | |
561 | * Returns %NULL for an empty list or a pointer to the tail element. | |
562 | * The reference count is not incremented and the reference is therefore | |
563 | * volatile. Use with caution. | |
564 | */ | |
565 | static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_) | |
566 | { | |
567 | struct sk_buff *list = ((struct sk_buff *)list_)->prev; | |
568 | if (list == (struct sk_buff *)list_) | |
569 | list = NULL; | |
570 | return list; | |
571 | } | |
572 | ||
573 | /** | |
574 | * skb_queue_len - get queue length | |
575 | * @list_: list to measure | |
576 | * | |
577 | * Return the length of an &sk_buff queue. | |
578 | */ | |
579 | static inline __u32 skb_queue_len(const struct sk_buff_head *list_) | |
580 | { | |
581 | return list_->qlen; | |
582 | } | |
583 | ||
584 | static inline void skb_queue_head_init(struct sk_buff_head *list) | |
585 | { | |
586 | spin_lock_init(&list->lock); | |
587 | list->prev = list->next = (struct sk_buff *)list; | |
588 | list->qlen = 0; | |
589 | } | |
590 | ||
591 | /* | |
592 | * Insert an sk_buff at the start of a list. | |
593 | * | |
594 | * The "__skb_xxxx()" functions are the non-atomic ones that | |
595 | * can only be called with interrupts disabled. | |
596 | */ | |
597 | ||
598 | /** | |
599 | * __skb_queue_head - queue a buffer at the list head | |
600 | * @list: list to use | |
601 | * @newsk: buffer to queue | |
602 | * | |
603 | * Queue a buffer at the start of a list. This function takes no locks | |
604 | * and you must therefore hold required locks before calling it. | |
605 | * | |
606 | * A buffer cannot be placed on two lists at the same time. | |
607 | */ | |
608 | extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk); | |
609 | static inline void __skb_queue_head(struct sk_buff_head *list, | |
610 | struct sk_buff *newsk) | |
611 | { | |
612 | struct sk_buff *prev, *next; | |
613 | ||
1da177e4 LT |
614 | list->qlen++; |
615 | prev = (struct sk_buff *)list; | |
616 | next = prev->next; | |
617 | newsk->next = next; | |
618 | newsk->prev = prev; | |
619 | next->prev = prev->next = newsk; | |
620 | } | |
621 | ||
622 | /** | |
623 | * __skb_queue_tail - queue a buffer at the list tail | |
624 | * @list: list to use | |
625 | * @newsk: buffer to queue | |
626 | * | |
627 | * Queue a buffer at the end of a list. This function takes no locks | |
628 | * and you must therefore hold required locks before calling it. | |
629 | * | |
630 | * A buffer cannot be placed on two lists at the same time. | |
631 | */ | |
632 | extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk); | |
633 | static inline void __skb_queue_tail(struct sk_buff_head *list, | |
634 | struct sk_buff *newsk) | |
635 | { | |
636 | struct sk_buff *prev, *next; | |
637 | ||
1da177e4 LT |
638 | list->qlen++; |
639 | next = (struct sk_buff *)list; | |
640 | prev = next->prev; | |
641 | newsk->next = next; | |
642 | newsk->prev = prev; | |
643 | next->prev = prev->next = newsk; | |
644 | } | |
645 | ||
646 | ||
647 | /** | |
648 | * __skb_dequeue - remove from the head of the queue | |
649 | * @list: list to dequeue from | |
650 | * | |
651 | * Remove the head of the list. This function does not take any locks | |
652 | * so must be used with appropriate locks held only. The head item is | |
653 | * returned or %NULL if the list is empty. | |
654 | */ | |
655 | extern struct sk_buff *skb_dequeue(struct sk_buff_head *list); | |
656 | static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list) | |
657 | { | |
658 | struct sk_buff *next, *prev, *result; | |
659 | ||
660 | prev = (struct sk_buff *) list; | |
661 | next = prev->next; | |
662 | result = NULL; | |
663 | if (next != prev) { | |
664 | result = next; | |
665 | next = next->next; | |
666 | list->qlen--; | |
667 | next->prev = prev; | |
668 | prev->next = next; | |
669 | result->next = result->prev = NULL; | |
1da177e4 LT |
670 | } |
671 | return result; | |
672 | } | |
673 | ||
674 | ||
675 | /* | |
676 | * Insert a packet on a list. | |
677 | */ | |
8728b834 | 678 | extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list); |
1da177e4 LT |
679 | static inline void __skb_insert(struct sk_buff *newsk, |
680 | struct sk_buff *prev, struct sk_buff *next, | |
681 | struct sk_buff_head *list) | |
682 | { | |
683 | newsk->next = next; | |
684 | newsk->prev = prev; | |
685 | next->prev = prev->next = newsk; | |
1da177e4 LT |
686 | list->qlen++; |
687 | } | |
688 | ||
689 | /* | |
690 | * Place a packet after a given packet in a list. | |
691 | */ | |
8728b834 DM |
692 | extern void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list); |
693 | static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) | |
1da177e4 | 694 | { |
8728b834 | 695 | __skb_insert(newsk, old, old->next, list); |
1da177e4 LT |
696 | } |
697 | ||
698 | /* | |
699 | * remove sk_buff from list. _Must_ be called atomically, and with | |
700 | * the list known.. | |
701 | */ | |
8728b834 | 702 | extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list); |
1da177e4 LT |
703 | static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) |
704 | { | |
705 | struct sk_buff *next, *prev; | |
706 | ||
707 | list->qlen--; | |
708 | next = skb->next; | |
709 | prev = skb->prev; | |
710 | skb->next = skb->prev = NULL; | |
1da177e4 LT |
711 | next->prev = prev; |
712 | prev->next = next; | |
713 | } | |
714 | ||
715 | ||
716 | /* XXX: more streamlined implementation */ | |
717 | ||
718 | /** | |
719 | * __skb_dequeue_tail - remove from the tail of the queue | |
720 | * @list: list to dequeue from | |
721 | * | |
722 | * Remove the tail of the list. This function does not take any locks | |
723 | * so must be used with appropriate locks held only. The tail item is | |
724 | * returned or %NULL if the list is empty. | |
725 | */ | |
726 | extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list); | |
727 | static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list) | |
728 | { | |
729 | struct sk_buff *skb = skb_peek_tail(list); | |
730 | if (skb) | |
731 | __skb_unlink(skb, list); | |
732 | return skb; | |
733 | } | |
734 | ||
735 | ||
736 | static inline int skb_is_nonlinear(const struct sk_buff *skb) | |
737 | { | |
738 | return skb->data_len; | |
739 | } | |
740 | ||
741 | static inline unsigned int skb_headlen(const struct sk_buff *skb) | |
742 | { | |
743 | return skb->len - skb->data_len; | |
744 | } | |
745 | ||
746 | static inline int skb_pagelen(const struct sk_buff *skb) | |
747 | { | |
748 | int i, len = 0; | |
749 | ||
750 | for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) | |
751 | len += skb_shinfo(skb)->frags[i].size; | |
752 | return len + skb_headlen(skb); | |
753 | } | |
754 | ||
755 | static inline void skb_fill_page_desc(struct sk_buff *skb, int i, | |
756 | struct page *page, int off, int size) | |
757 | { | |
758 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; | |
759 | ||
760 | frag->page = page; | |
761 | frag->page_offset = off; | |
762 | frag->size = size; | |
763 | skb_shinfo(skb)->nr_frags = i + 1; | |
764 | } | |
765 | ||
766 | #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags) | |
767 | #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list) | |
768 | #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb)) | |
769 | ||
770 | /* | |
771 | * Add data to an sk_buff | |
772 | */ | |
773 | static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len) | |
774 | { | |
775 | unsigned char *tmp = skb->tail; | |
776 | SKB_LINEAR_ASSERT(skb); | |
777 | skb->tail += len; | |
778 | skb->len += len; | |
779 | return tmp; | |
780 | } | |
781 | ||
782 | /** | |
783 | * skb_put - add data to a buffer | |
784 | * @skb: buffer to use | |
785 | * @len: amount of data to add | |
786 | * | |
787 | * This function extends the used data area of the buffer. If this would | |
788 | * exceed the total buffer size the kernel will panic. A pointer to the | |
789 | * first byte of the extra data is returned. | |
790 | */ | |
791 | static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len) | |
792 | { | |
793 | unsigned char *tmp = skb->tail; | |
794 | SKB_LINEAR_ASSERT(skb); | |
795 | skb->tail += len; | |
796 | skb->len += len; | |
797 | if (unlikely(skb->tail>skb->end)) | |
798 | skb_over_panic(skb, len, current_text_addr()); | |
799 | return tmp; | |
800 | } | |
801 | ||
802 | static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len) | |
803 | { | |
804 | skb->data -= len; | |
805 | skb->len += len; | |
806 | return skb->data; | |
807 | } | |
808 | ||
809 | /** | |
810 | * skb_push - add data to the start of a buffer | |
811 | * @skb: buffer to use | |
812 | * @len: amount of data to add | |
813 | * | |
814 | * This function extends the used data area of the buffer at the buffer | |
815 | * start. If this would exceed the total buffer headroom the kernel will | |
816 | * panic. A pointer to the first byte of the extra data is returned. | |
817 | */ | |
818 | static inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len) | |
819 | { | |
820 | skb->data -= len; | |
821 | skb->len += len; | |
822 | if (unlikely(skb->data<skb->head)) | |
823 | skb_under_panic(skb, len, current_text_addr()); | |
824 | return skb->data; | |
825 | } | |
826 | ||
827 | static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len) | |
828 | { | |
829 | skb->len -= len; | |
830 | BUG_ON(skb->len < skb->data_len); | |
831 | return skb->data += len; | |
832 | } | |
833 | ||
834 | /** | |
835 | * skb_pull - remove data from the start of a buffer | |
836 | * @skb: buffer to use | |
837 | * @len: amount of data to remove | |
838 | * | |
839 | * This function removes data from the start of a buffer, returning | |
840 | * the memory to the headroom. A pointer to the next data in the buffer | |
841 | * is returned. Once the data has been pulled future pushes will overwrite | |
842 | * the old data. | |
843 | */ | |
844 | static inline unsigned char *skb_pull(struct sk_buff *skb, unsigned int len) | |
845 | { | |
846 | return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len); | |
847 | } | |
848 | ||
849 | extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta); | |
850 | ||
851 | static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len) | |
852 | { | |
853 | if (len > skb_headlen(skb) && | |
854 | !__pskb_pull_tail(skb, len-skb_headlen(skb))) | |
855 | return NULL; | |
856 | skb->len -= len; | |
857 | return skb->data += len; | |
858 | } | |
859 | ||
860 | static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len) | |
861 | { | |
862 | return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len); | |
863 | } | |
864 | ||
865 | static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len) | |
866 | { | |
867 | if (likely(len <= skb_headlen(skb))) | |
868 | return 1; | |
869 | if (unlikely(len > skb->len)) | |
870 | return 0; | |
871 | return __pskb_pull_tail(skb, len-skb_headlen(skb)) != NULL; | |
872 | } | |
873 | ||
874 | /** | |
875 | * skb_headroom - bytes at buffer head | |
876 | * @skb: buffer to check | |
877 | * | |
878 | * Return the number of bytes of free space at the head of an &sk_buff. | |
879 | */ | |
880 | static inline int skb_headroom(const struct sk_buff *skb) | |
881 | { | |
882 | return skb->data - skb->head; | |
883 | } | |
884 | ||
885 | /** | |
886 | * skb_tailroom - bytes at buffer end | |
887 | * @skb: buffer to check | |
888 | * | |
889 | * Return the number of bytes of free space at the tail of an sk_buff | |
890 | */ | |
891 | static inline int skb_tailroom(const struct sk_buff *skb) | |
892 | { | |
893 | return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail; | |
894 | } | |
895 | ||
896 | /** | |
897 | * skb_reserve - adjust headroom | |
898 | * @skb: buffer to alter | |
899 | * @len: bytes to move | |
900 | * | |
901 | * Increase the headroom of an empty &sk_buff by reducing the tail | |
902 | * room. This is only allowed for an empty buffer. | |
903 | */ | |
904 | static inline void skb_reserve(struct sk_buff *skb, unsigned int len) | |
905 | { | |
906 | skb->data += len; | |
907 | skb->tail += len; | |
908 | } | |
909 | ||
910 | /* | |
911 | * CPUs often take a performance hit when accessing unaligned memory | |
912 | * locations. The actual performance hit varies, it can be small if the | |
913 | * hardware handles it or large if we have to take an exception and fix it | |
914 | * in software. | |
915 | * | |
916 | * Since an ethernet header is 14 bytes network drivers often end up with | |
917 | * the IP header at an unaligned offset. The IP header can be aligned by | |
918 | * shifting the start of the packet by 2 bytes. Drivers should do this | |
919 | * with: | |
920 | * | |
921 | * skb_reserve(NET_IP_ALIGN); | |
922 | * | |
923 | * The downside to this alignment of the IP header is that the DMA is now | |
924 | * unaligned. On some architectures the cost of an unaligned DMA is high | |
925 | * and this cost outweighs the gains made by aligning the IP header. | |
926 | * | |
927 | * Since this trade off varies between architectures, we allow NET_IP_ALIGN | |
928 | * to be overridden. | |
929 | */ | |
930 | #ifndef NET_IP_ALIGN | |
931 | #define NET_IP_ALIGN 2 | |
932 | #endif | |
933 | ||
934 | extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc); | |
935 | ||
936 | static inline void __skb_trim(struct sk_buff *skb, unsigned int len) | |
937 | { | |
938 | if (!skb->data_len) { | |
939 | skb->len = len; | |
940 | skb->tail = skb->data + len; | |
941 | } else | |
942 | ___pskb_trim(skb, len, 0); | |
943 | } | |
944 | ||
945 | /** | |
946 | * skb_trim - remove end from a buffer | |
947 | * @skb: buffer to alter | |
948 | * @len: new length | |
949 | * | |
950 | * Cut the length of a buffer down by removing data from the tail. If | |
951 | * the buffer is already under the length specified it is not modified. | |
952 | */ | |
953 | static inline void skb_trim(struct sk_buff *skb, unsigned int len) | |
954 | { | |
955 | if (skb->len > len) | |
956 | __skb_trim(skb, len); | |
957 | } | |
958 | ||
959 | ||
960 | static inline int __pskb_trim(struct sk_buff *skb, unsigned int len) | |
961 | { | |
962 | if (!skb->data_len) { | |
963 | skb->len = len; | |
964 | skb->tail = skb->data+len; | |
965 | return 0; | |
966 | } | |
967 | return ___pskb_trim(skb, len, 1); | |
968 | } | |
969 | ||
970 | static inline int pskb_trim(struct sk_buff *skb, unsigned int len) | |
971 | { | |
972 | return (len < skb->len) ? __pskb_trim(skb, len) : 0; | |
973 | } | |
974 | ||
975 | /** | |
976 | * skb_orphan - orphan a buffer | |
977 | * @skb: buffer to orphan | |
978 | * | |
979 | * If a buffer currently has an owner then we call the owner's | |
980 | * destructor function and make the @skb unowned. The buffer continues | |
981 | * to exist but is no longer charged to its former owner. | |
982 | */ | |
983 | static inline void skb_orphan(struct sk_buff *skb) | |
984 | { | |
985 | if (skb->destructor) | |
986 | skb->destructor(skb); | |
987 | skb->destructor = NULL; | |
988 | skb->sk = NULL; | |
989 | } | |
990 | ||
991 | /** | |
992 | * __skb_queue_purge - empty a list | |
993 | * @list: list to empty | |
994 | * | |
995 | * Delete all buffers on an &sk_buff list. Each buffer is removed from | |
996 | * the list and one reference dropped. This function does not take the | |
997 | * list lock and the caller must hold the relevant locks to use it. | |
998 | */ | |
999 | extern void skb_queue_purge(struct sk_buff_head *list); | |
1000 | static inline void __skb_queue_purge(struct sk_buff_head *list) | |
1001 | { | |
1002 | struct sk_buff *skb; | |
1003 | while ((skb = __skb_dequeue(list)) != NULL) | |
1004 | kfree_skb(skb); | |
1005 | } | |
1006 | ||
4dc3b16b | 1007 | #ifndef CONFIG_HAVE_ARCH_DEV_ALLOC_SKB |
1da177e4 LT |
1008 | /** |
1009 | * __dev_alloc_skb - allocate an skbuff for sending | |
1010 | * @length: length to allocate | |
1011 | * @gfp_mask: get_free_pages mask, passed to alloc_skb | |
1012 | * | |
1013 | * Allocate a new &sk_buff and assign it a usage count of one. The | |
1014 | * buffer has unspecified headroom built in. Users should allocate | |
1015 | * the headroom they think they need without accounting for the | |
1016 | * built in space. The built in space is used for optimisations. | |
1017 | * | |
1018 | * %NULL is returned in there is no free memory. | |
1019 | */ | |
1da177e4 | 1020 | static inline struct sk_buff *__dev_alloc_skb(unsigned int length, |
dd0fc66f | 1021 | gfp_t gfp_mask) |
1da177e4 LT |
1022 | { |
1023 | struct sk_buff *skb = alloc_skb(length + 16, gfp_mask); | |
1024 | if (likely(skb)) | |
1025 | skb_reserve(skb, 16); | |
1026 | return skb; | |
1027 | } | |
1028 | #else | |
1029 | extern struct sk_buff *__dev_alloc_skb(unsigned int length, int gfp_mask); | |
1030 | #endif | |
1031 | ||
1032 | /** | |
1033 | * dev_alloc_skb - allocate an skbuff for sending | |
1034 | * @length: length to allocate | |
1035 | * | |
1036 | * Allocate a new &sk_buff and assign it a usage count of one. The | |
1037 | * buffer has unspecified headroom built in. Users should allocate | |
1038 | * the headroom they think they need without accounting for the | |
1039 | * built in space. The built in space is used for optimisations. | |
1040 | * | |
1041 | * %NULL is returned in there is no free memory. Although this function | |
1042 | * allocates memory it can be called from an interrupt. | |
1043 | */ | |
1044 | static inline struct sk_buff *dev_alloc_skb(unsigned int length) | |
1045 | { | |
1046 | return __dev_alloc_skb(length, GFP_ATOMIC); | |
1047 | } | |
1048 | ||
1049 | /** | |
1050 | * skb_cow - copy header of skb when it is required | |
1051 | * @skb: buffer to cow | |
1052 | * @headroom: needed headroom | |
1053 | * | |
1054 | * If the skb passed lacks sufficient headroom or its data part | |
1055 | * is shared, data is reallocated. If reallocation fails, an error | |
1056 | * is returned and original skb is not changed. | |
1057 | * | |
1058 | * The result is skb with writable area skb->head...skb->tail | |
1059 | * and at least @headroom of space at head. | |
1060 | */ | |
1061 | static inline int skb_cow(struct sk_buff *skb, unsigned int headroom) | |
1062 | { | |
1063 | int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb); | |
1064 | ||
1065 | if (delta < 0) | |
1066 | delta = 0; | |
1067 | ||
1068 | if (delta || skb_cloned(skb)) | |
1069 | return pskb_expand_head(skb, (delta + 15) & ~15, 0, GFP_ATOMIC); | |
1070 | return 0; | |
1071 | } | |
1072 | ||
1073 | /** | |
1074 | * skb_padto - pad an skbuff up to a minimal size | |
1075 | * @skb: buffer to pad | |
1076 | * @len: minimal length | |
1077 | * | |
1078 | * Pads up a buffer to ensure the trailing bytes exist and are | |
1079 | * blanked. If the buffer already contains sufficient data it | |
1080 | * is untouched. Returns the buffer, which may be a replacement | |
1081 | * for the original, or NULL for out of memory - in which case | |
1082 | * the original buffer is still freed. | |
1083 | */ | |
1084 | ||
1085 | static inline struct sk_buff *skb_padto(struct sk_buff *skb, unsigned int len) | |
1086 | { | |
1087 | unsigned int size = skb->len; | |
1088 | if (likely(size >= len)) | |
1089 | return skb; | |
1090 | return skb_pad(skb, len-size); | |
1091 | } | |
1092 | ||
1093 | static inline int skb_add_data(struct sk_buff *skb, | |
1094 | char __user *from, int copy) | |
1095 | { | |
1096 | const int off = skb->len; | |
1097 | ||
1098 | if (skb->ip_summed == CHECKSUM_NONE) { | |
1099 | int err = 0; | |
1100 | unsigned int csum = csum_and_copy_from_user(from, | |
1101 | skb_put(skb, copy), | |
1102 | copy, 0, &err); | |
1103 | if (!err) { | |
1104 | skb->csum = csum_block_add(skb->csum, csum, off); | |
1105 | return 0; | |
1106 | } | |
1107 | } else if (!copy_from_user(skb_put(skb, copy), from, copy)) | |
1108 | return 0; | |
1109 | ||
1110 | __skb_trim(skb, off); | |
1111 | return -EFAULT; | |
1112 | } | |
1113 | ||
1114 | static inline int skb_can_coalesce(struct sk_buff *skb, int i, | |
1115 | struct page *page, int off) | |
1116 | { | |
1117 | if (i) { | |
1118 | struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1]; | |
1119 | ||
1120 | return page == frag->page && | |
1121 | off == frag->page_offset + frag->size; | |
1122 | } | |
1123 | return 0; | |
1124 | } | |
1125 | ||
1126 | /** | |
1127 | * skb_linearize - convert paged skb to linear one | |
1128 | * @skb: buffer to linarize | |
1129 | * @gfp: allocation mode | |
1130 | * | |
1131 | * If there is no free memory -ENOMEM is returned, otherwise zero | |
1132 | * is returned and the old skb data released. | |
1133 | */ | |
dd0fc66f AV |
1134 | extern int __skb_linearize(struct sk_buff *skb, gfp_t gfp); |
1135 | static inline int skb_linearize(struct sk_buff *skb, gfp_t gfp) | |
1da177e4 LT |
1136 | { |
1137 | return __skb_linearize(skb, gfp); | |
1138 | } | |
1139 | ||
1140 | /** | |
1141 | * skb_postpull_rcsum - update checksum for received skb after pull | |
1142 | * @skb: buffer to update | |
1143 | * @start: start of data before pull | |
1144 | * @len: length of data pulled | |
1145 | * | |
1146 | * After doing a pull on a received packet, you need to call this to | |
1147 | * update the CHECKSUM_HW checksum, or set ip_summed to CHECKSUM_NONE | |
1148 | * so that it can be recomputed from scratch. | |
1149 | */ | |
1150 | ||
1151 | static inline void skb_postpull_rcsum(struct sk_buff *skb, | |
1152 | const void *start, int len) | |
1153 | { | |
1154 | if (skb->ip_summed == CHECKSUM_HW) | |
1155 | skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0)); | |
1156 | } | |
1157 | ||
1158 | /** | |
1159 | * pskb_trim_rcsum - trim received skb and update checksum | |
1160 | * @skb: buffer to trim | |
1161 | * @len: new length | |
1162 | * | |
1163 | * This is exactly the same as pskb_trim except that it ensures the | |
1164 | * checksum of received packets are still valid after the operation. | |
1165 | */ | |
1166 | ||
1167 | static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) | |
1168 | { | |
0e4e4220 | 1169 | if (likely(len >= skb->len)) |
1da177e4 LT |
1170 | return 0; |
1171 | if (skb->ip_summed == CHECKSUM_HW) | |
1172 | skb->ip_summed = CHECKSUM_NONE; | |
1173 | return __pskb_trim(skb, len); | |
1174 | } | |
1175 | ||
1176 | static inline void *kmap_skb_frag(const skb_frag_t *frag) | |
1177 | { | |
1178 | #ifdef CONFIG_HIGHMEM | |
1179 | BUG_ON(in_irq()); | |
1180 | ||
1181 | local_bh_disable(); | |
1182 | #endif | |
1183 | return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ); | |
1184 | } | |
1185 | ||
1186 | static inline void kunmap_skb_frag(void *vaddr) | |
1187 | { | |
1188 | kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ); | |
1189 | #ifdef CONFIG_HIGHMEM | |
1190 | local_bh_enable(); | |
1191 | #endif | |
1192 | } | |
1193 | ||
1194 | #define skb_queue_walk(queue, skb) \ | |
1195 | for (skb = (queue)->next; \ | |
1196 | prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \ | |
1197 | skb = skb->next) | |
1198 | ||
1199 | ||
1200 | extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, | |
1201 | int noblock, int *err); | |
1202 | extern unsigned int datagram_poll(struct file *file, struct socket *sock, | |
1203 | struct poll_table_struct *wait); | |
1204 | extern int skb_copy_datagram_iovec(const struct sk_buff *from, | |
1205 | int offset, struct iovec *to, | |
1206 | int size); | |
1207 | extern int skb_copy_and_csum_datagram_iovec(const | |
1208 | struct sk_buff *skb, | |
1209 | int hlen, | |
1210 | struct iovec *iov); | |
1211 | extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb); | |
1212 | extern unsigned int skb_checksum(const struct sk_buff *skb, int offset, | |
1213 | int len, unsigned int csum); | |
1214 | extern int skb_copy_bits(const struct sk_buff *skb, int offset, | |
1215 | void *to, int len); | |
357b40a1 HX |
1216 | extern int skb_store_bits(const struct sk_buff *skb, int offset, |
1217 | void *from, int len); | |
1da177e4 LT |
1218 | extern unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, |
1219 | int offset, u8 *to, int len, | |
1220 | unsigned int csum); | |
1221 | extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to); | |
1222 | extern void skb_split(struct sk_buff *skb, | |
1223 | struct sk_buff *skb1, const u32 len); | |
1224 | ||
20380731 ACM |
1225 | extern void skb_release_data(struct sk_buff *skb); |
1226 | ||
1da177e4 LT |
1227 | static inline void *skb_header_pointer(const struct sk_buff *skb, int offset, |
1228 | int len, void *buffer) | |
1229 | { | |
1230 | int hlen = skb_headlen(skb); | |
1231 | ||
55820ee2 | 1232 | if (hlen - offset >= len) |
1da177e4 LT |
1233 | return skb->data + offset; |
1234 | ||
1235 | if (skb_copy_bits(skb, offset, buffer, len) < 0) | |
1236 | return NULL; | |
1237 | ||
1238 | return buffer; | |
1239 | } | |
1240 | ||
1241 | extern void skb_init(void); | |
1242 | extern void skb_add_mtu(int mtu); | |
1243 | ||
a61bbcf2 PM |
1244 | /** |
1245 | * skb_get_timestamp - get timestamp from a skb | |
1246 | * @skb: skb to get stamp from | |
1247 | * @stamp: pointer to struct timeval to store stamp in | |
1248 | * | |
1249 | * Timestamps are stored in the skb as offsets to a base timestamp. | |
1250 | * This function converts the offset back to a struct timeval and stores | |
1251 | * it in stamp. | |
1252 | */ | |
f2c38398 | 1253 | static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *stamp) |
a61bbcf2 PM |
1254 | { |
1255 | stamp->tv_sec = skb->tstamp.off_sec; | |
1256 | stamp->tv_usec = skb->tstamp.off_usec; | |
a61bbcf2 PM |
1257 | } |
1258 | ||
1259 | /** | |
1260 | * skb_set_timestamp - set timestamp of a skb | |
1261 | * @skb: skb to set stamp of | |
1262 | * @stamp: pointer to struct timeval to get stamp from | |
1263 | * | |
1264 | * Timestamps are stored in the skb as offsets to a base timestamp. | |
1265 | * This function converts a struct timeval to an offset and stores | |
1266 | * it in the skb. | |
1267 | */ | |
f2c38398 | 1268 | static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp) |
a61bbcf2 | 1269 | { |
325ed823 HX |
1270 | skb->tstamp.off_sec = stamp->tv_sec; |
1271 | skb->tstamp.off_usec = stamp->tv_usec; | |
a61bbcf2 PM |
1272 | } |
1273 | ||
1274 | extern void __net_timestamp(struct sk_buff *skb); | |
1275 | ||
1da177e4 LT |
1276 | #ifdef CONFIG_NETFILTER |
1277 | static inline void nf_conntrack_put(struct nf_conntrack *nfct) | |
1278 | { | |
1279 | if (nfct && atomic_dec_and_test(&nfct->use)) | |
1280 | nfct->destroy(nfct); | |
1281 | } | |
1282 | static inline void nf_conntrack_get(struct nf_conntrack *nfct) | |
1283 | { | |
1284 | if (nfct) | |
1285 | atomic_inc(&nfct->use); | |
1286 | } | |
1287 | static inline void nf_reset(struct sk_buff *skb) | |
1288 | { | |
1289 | nf_conntrack_put(skb->nfct); | |
1290 | skb->nfct = NULL; | |
1da177e4 LT |
1291 | } |
1292 | ||
1293 | #ifdef CONFIG_BRIDGE_NETFILTER | |
1294 | static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge) | |
1295 | { | |
1296 | if (nf_bridge && atomic_dec_and_test(&nf_bridge->use)) | |
1297 | kfree(nf_bridge); | |
1298 | } | |
1299 | static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge) | |
1300 | { | |
1301 | if (nf_bridge) | |
1302 | atomic_inc(&nf_bridge->use); | |
1303 | } | |
1304 | #endif /* CONFIG_BRIDGE_NETFILTER */ | |
1305 | #else /* CONFIG_NETFILTER */ | |
1306 | static inline void nf_reset(struct sk_buff *skb) {} | |
1307 | #endif /* CONFIG_NETFILTER */ | |
1308 | ||
1309 | #endif /* __KERNEL__ */ | |
1310 | #endif /* _LINUX_SKBUFF_H */ |