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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Thomas Graf3fc7e8a2005-06-23 21:00:17 -070030#include <linux/textsearch.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#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
Linus Torvalds1da177e2005-04-16 15:20:36 -070087struct net_device;
88
89#ifdef CONFIG_NETFILTER
90struct nf_conntrack {
91 atomic_t use;
92 void (*destroy)(struct nf_conntrack *);
93};
94
95#ifdef CONFIG_BRIDGE_NETFILTER
96struct 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
110struct 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
119struct 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
124typedef struct skb_frag_struct skb_frag_t;
125
126struct 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 */
135struct skb_shared_info {
136 atomic_t dataref;
137 unsigned int nr_frags;
138 unsigned short tso_size;
139 unsigned short tso_segs;
Ananda Rajue89e9cf2005-10-18 15:46:41 -0700140 unsigned short ufo_size;
141 unsigned int ip6_frag_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 struct sk_buff *frag_list;
143 skb_frag_t frags[MAX_SKB_FRAGS];
144};
145
146/* We divide dataref into two halves. The higher 16 bits hold references
147 * to the payload part of skb->data. The lower 16 bits hold references to
148 * the entire skb->data. It is up to the users of the skb to agree on
149 * where the payload starts.
150 *
151 * All users must obey the rule that the skb->data reference count must be
152 * greater than or equal to the payload reference count.
153 *
154 * Holding a reference to the payload part means that the user does not
155 * care about modifications to the header part of skb->data.
156 */
157#define SKB_DATAREF_SHIFT 16
158#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
159
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700160struct skb_timeval {
161 u32 off_sec;
162 u32 off_usec;
163};
164
David S. Millerd179cd12005-08-17 14:57:30 -0700165
166enum {
167 SKB_FCLONE_UNAVAILABLE,
168 SKB_FCLONE_ORIG,
169 SKB_FCLONE_CLONE,
170};
171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172/**
173 * struct sk_buff - socket buffer
174 * @next: Next buffer in list
175 * @prev: Previous buffer in list
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 * @sk: Socket we are owned by
Herbert Xu325ed822005-10-03 13:57:23 -0700177 * @tstamp: Time we arrived
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 * @dev: Device we arrived on/are leaving by
179 * @input_dev: Device we arrived on
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 * @h: Transport layer header
181 * @nh: Network layer header
182 * @mac: Link layer header
Martin Waitz67be2dd2005-05-01 08:59:26 -0700183 * @dst: destination entry
184 * @sp: the security path, used for xfrm
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 * @cb: Control buffer. Free for use by every layer. Put private vars here
186 * @len: Length of actual data
187 * @data_len: Data length
188 * @mac_len: Length of link layer header
189 * @csum: Checksum
Martin Waitz67be2dd2005-05-01 08:59:26 -0700190 * @local_df: allow local fragmentation
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 * @cloned: Head may be cloned (check refcnt to be sure)
192 * @nohdr: Payload reference only, must not modify header
193 * @pkt_type: Packet class
Randy Dunlapc83c2482005-10-18 22:07:41 -0700194 * @fclone: skbuff clone status
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 * @ip_summed: Driver fed us an IP checksum
196 * @priority: Packet queueing priority
197 * @users: User count - see {datagram,tcp}.c
198 * @protocol: Packet protocol from driver
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 * @truesize: Buffer size
200 * @head: Head of buffer
201 * @data: Data head pointer
202 * @tail: Tail pointer
203 * @end: End pointer
204 * @destructor: Destruct function
205 * @nfmark: Can be used for communication between hooks
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 * @nfct: Associated connection, if any
Randy Dunlapc83c2482005-10-18 22:07:41 -0700207 * @ipvs_property: skbuff is owned by ipvs
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 * @nfctinfo: Relationship of this skb to the connection
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 * @tc_index: Traffic control index
211 * @tc_verd: traffic control verdict
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 */
213
214struct sk_buff {
215 /* These two members must be first. */
216 struct sk_buff *next;
217 struct sk_buff *prev;
218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 struct sock *sk;
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700220 struct skb_timeval tstamp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 struct net_device *dev;
222 struct net_device *input_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
224 union {
225 struct tcphdr *th;
226 struct udphdr *uh;
227 struct icmphdr *icmph;
228 struct igmphdr *igmph;
229 struct iphdr *ipiph;
230 struct ipv6hdr *ipv6h;
231 unsigned char *raw;
232 } h;
233
234 union {
235 struct iphdr *iph;
236 struct ipv6hdr *ipv6h;
237 struct arphdr *arph;
238 unsigned char *raw;
239 } nh;
240
241 union {
242 unsigned char *raw;
243 } mac;
244
245 struct dst_entry *dst;
246 struct sec_path *sp;
247
248 /*
249 * This is the control buffer. It is free to use for every
250 * layer. Please put your private variables there. If you
251 * want to keep them across layers you have to do a skb_clone()
252 * first. This is owned by whoever has the skb queued ATM.
253 */
254 char cb[40];
255
256 unsigned int len,
257 data_len,
258 mac_len,
259 csum;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 __u32 priority;
Thomas Graf1cbb3382005-07-05 14:13:41 -0700261 __u8 local_df:1,
262 cloned:1,
263 ip_summed:2,
Harald Welte6869c4d2005-08-09 19:24:19 -0700264 nohdr:1,
265 nfctinfo:3;
David S. Millerd179cd12005-08-17 14:57:30 -0700266 __u8 pkt_type:3,
267 fclone:2;
Alexey Dobriyana0d3bea2005-08-11 16:05:50 -0700268 __be16 protocol;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269
270 void (*destructor)(struct sk_buff *skb);
271#ifdef CONFIG_NETFILTER
Harald Weltebf3a46a2005-08-09 19:22:01 -0700272 __u32 nfmark;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 struct nf_conntrack *nfct;
Harald Welte6869c4d2005-08-09 19:24:19 -0700274#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
275 __u8 ipvs_property:1;
276#endif
Yasuyuki Kozakai9fb9cbb2005-11-09 16:38:16 -0800277#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
278 struct sk_buff *nfct_reasm;
279#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280#ifdef CONFIG_BRIDGE_NETFILTER
281 struct nf_bridge_info *nf_bridge;
282#endif
283#endif /* CONFIG_NETFILTER */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284#ifdef CONFIG_NET_SCHED
Patrick McHardyb6b99eb2005-08-09 19:33:51 -0700285 __u16 tc_index; /* traffic control index */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286#ifdef CONFIG_NET_CLS_ACT
Patrick McHardyb6b99eb2005-08-09 19:33:51 -0700287 __u16 tc_verd; /* traffic control verdict */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289#endif
290
291
292 /* These elements must be at the end, see alloc_skb() for details. */
293 unsigned int truesize;
294 atomic_t users;
295 unsigned char *head,
296 *data,
297 *tail,
298 *end;
299};
300
301#ifdef __KERNEL__
302/*
303 * Handling routines are only of interest to the kernel
304 */
305#include <linux/slab.h>
306
307#include <asm/system.h>
308
309extern void __kfree_skb(struct sk_buff *skb);
David S. Millerd179cd12005-08-17 14:57:30 -0700310extern struct sk_buff *__alloc_skb(unsigned int size,
Al Virodd0fc662005-10-07 07:46:04 +0100311 gfp_t priority, int fclone);
David S. Millerd179cd12005-08-17 14:57:30 -0700312static inline struct sk_buff *alloc_skb(unsigned int size,
Al Virodd0fc662005-10-07 07:46:04 +0100313 gfp_t priority)
David S. Millerd179cd12005-08-17 14:57:30 -0700314{
315 return __alloc_skb(size, priority, 0);
316}
317
318static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
Al Virodd0fc662005-10-07 07:46:04 +0100319 gfp_t priority)
David S. Millerd179cd12005-08-17 14:57:30 -0700320{
321 return __alloc_skb(size, priority, 1);
322}
323
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324extern struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
Victor Fusco86a76ca2005-07-08 14:57:47 -0700325 unsigned int size,
Al Virodd0fc662005-10-07 07:46:04 +0100326 gfp_t priority);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327extern void kfree_skbmem(struct sk_buff *skb);
Victor Fusco86a76ca2005-07-08 14:57:47 -0700328extern struct sk_buff *skb_clone(struct sk_buff *skb,
Al Virodd0fc662005-10-07 07:46:04 +0100329 gfp_t priority);
Victor Fusco86a76ca2005-07-08 14:57:47 -0700330extern struct sk_buff *skb_copy(const struct sk_buff *skb,
Al Virodd0fc662005-10-07 07:46:04 +0100331 gfp_t priority);
Victor Fusco86a76ca2005-07-08 14:57:47 -0700332extern struct sk_buff *pskb_copy(struct sk_buff *skb,
Al Virodd0fc662005-10-07 07:46:04 +0100333 gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334extern int pskb_expand_head(struct sk_buff *skb,
Victor Fusco86a76ca2005-07-08 14:57:47 -0700335 int nhead, int ntail,
Al Virodd0fc662005-10-07 07:46:04 +0100336 gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
338 unsigned int headroom);
339extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
340 int newheadroom, int newtailroom,
Al Virodd0fc662005-10-07 07:46:04 +0100341 gfp_t priority);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342extern struct sk_buff * skb_pad(struct sk_buff *skb, int pad);
343#define dev_kfree_skb(a) kfree_skb(a)
344extern void skb_over_panic(struct sk_buff *skb, int len,
345 void *here);
346extern void skb_under_panic(struct sk_buff *skb, int len,
347 void *here);
348
Ananda Rajue89e9cf2005-10-18 15:46:41 -0700349extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
350 int getfrag(void *from, char *to, int offset,
351 int len,int odd, struct sk_buff *skb),
352 void *from, int length);
353
Thomas Graf677e90e2005-06-23 20:59:51 -0700354struct skb_seq_state
355{
356 __u32 lower_offset;
357 __u32 upper_offset;
358 __u32 frag_idx;
359 __u32 stepped_offset;
360 struct sk_buff *root_skb;
361 struct sk_buff *cur_skb;
362 __u8 *frag_data;
363};
364
365extern void skb_prepare_seq_read(struct sk_buff *skb,
366 unsigned int from, unsigned int to,
367 struct skb_seq_state *st);
368extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
369 struct skb_seq_state *st);
370extern void skb_abort_seq_read(struct skb_seq_state *st);
371
Thomas Graf3fc7e8a2005-06-23 21:00:17 -0700372extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
373 unsigned int to, struct ts_config *config,
374 struct ts_state *state);
375
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376/* Internal */
377#define skb_shinfo(SKB) ((struct skb_shared_info *)((SKB)->end))
378
379/**
380 * skb_queue_empty - check if a queue is empty
381 * @list: queue head
382 *
383 * Returns true if the queue is empty, false otherwise.
384 */
385static inline int skb_queue_empty(const struct sk_buff_head *list)
386{
387 return list->next == (struct sk_buff *)list;
388}
389
390/**
391 * skb_get - reference buffer
392 * @skb: buffer to reference
393 *
394 * Makes another reference to a socket buffer and returns a pointer
395 * to the buffer.
396 */
397static inline struct sk_buff *skb_get(struct sk_buff *skb)
398{
399 atomic_inc(&skb->users);
400 return skb;
401}
402
403/*
404 * If users == 1, we are the only owner and are can avoid redundant
405 * atomic change.
406 */
407
408/**
409 * kfree_skb - free an sk_buff
410 * @skb: buffer to free
411 *
412 * Drop a reference to the buffer and free it if the usage count has
413 * hit zero.
414 */
415static inline void kfree_skb(struct sk_buff *skb)
416{
417 if (likely(atomic_read(&skb->users) == 1))
418 smp_rmb();
419 else if (likely(!atomic_dec_and_test(&skb->users)))
420 return;
421 __kfree_skb(skb);
422}
423
424/**
425 * skb_cloned - is the buffer a clone
426 * @skb: buffer to check
427 *
428 * Returns true if the buffer was generated with skb_clone() and is
429 * one of multiple shared copies of the buffer. Cloned buffers are
430 * shared data so must not be written to under normal circumstances.
431 */
432static inline int skb_cloned(const struct sk_buff *skb)
433{
434 return skb->cloned &&
435 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
436}
437
438/**
439 * skb_header_cloned - is the header a clone
440 * @skb: buffer to check
441 *
442 * Returns true if modifying the header part of the buffer requires
443 * the data to be copied.
444 */
445static inline int skb_header_cloned(const struct sk_buff *skb)
446{
447 int dataref;
448
449 if (!skb->cloned)
450 return 0;
451
452 dataref = atomic_read(&skb_shinfo(skb)->dataref);
453 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
454 return dataref != 1;
455}
456
457/**
458 * skb_header_release - release reference to header
459 * @skb: buffer to operate on
460 *
461 * Drop a reference to the header part of the buffer. This is done
462 * by acquiring a payload reference. You must not read from the header
463 * part of skb->data after this.
464 */
465static inline void skb_header_release(struct sk_buff *skb)
466{
467 BUG_ON(skb->nohdr);
468 skb->nohdr = 1;
469 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
470}
471
472/**
473 * skb_shared - is the buffer shared
474 * @skb: buffer to check
475 *
476 * Returns true if more than one person has a reference to this
477 * buffer.
478 */
479static inline int skb_shared(const struct sk_buff *skb)
480{
481 return atomic_read(&skb->users) != 1;
482}
483
484/**
485 * skb_share_check - check if buffer is shared and if so clone it
486 * @skb: buffer to check
487 * @pri: priority for memory allocation
488 *
489 * If the buffer is shared the buffer is cloned and the old copy
490 * drops a reference. A new clone with a single reference is returned.
491 * If the buffer is not shared the original buffer is returned. When
492 * being called from interrupt status or with spinlocks held pri must
493 * be GFP_ATOMIC.
494 *
495 * NULL is returned on a memory allocation failure.
496 */
Victor Fusco86a76ca2005-07-08 14:57:47 -0700497static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
Al Virodd0fc662005-10-07 07:46:04 +0100498 gfp_t pri)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499{
500 might_sleep_if(pri & __GFP_WAIT);
501 if (skb_shared(skb)) {
502 struct sk_buff *nskb = skb_clone(skb, pri);
503 kfree_skb(skb);
504 skb = nskb;
505 }
506 return skb;
507}
508
509/*
510 * Copy shared buffers into a new sk_buff. We effectively do COW on
511 * packets to handle cases where we have a local reader and forward
512 * and a couple of other messy ones. The normal one is tcpdumping
513 * a packet thats being forwarded.
514 */
515
516/**
517 * skb_unshare - make a copy of a shared buffer
518 * @skb: buffer to check
519 * @pri: priority for memory allocation
520 *
521 * If the socket buffer is a clone then this function creates a new
522 * copy of the data, drops a reference count on the old copy and returns
523 * the new copy with the reference count at 1. If the buffer is not a clone
524 * the original buffer is returned. When called with a spinlock held or
525 * from interrupt state @pri must be %GFP_ATOMIC
526 *
527 * %NULL is returned on a memory allocation failure.
528 */
Victor Fuscoe2bf5212005-07-18 13:36:38 -0700529static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
Al Virodd0fc662005-10-07 07:46:04 +0100530 gfp_t pri)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531{
532 might_sleep_if(pri & __GFP_WAIT);
533 if (skb_cloned(skb)) {
534 struct sk_buff *nskb = skb_copy(skb, pri);
535 kfree_skb(skb); /* Free our shared copy */
536 skb = nskb;
537 }
538 return skb;
539}
540
541/**
542 * skb_peek
543 * @list_: list to peek at
544 *
545 * Peek an &sk_buff. Unlike most other operations you _MUST_
546 * be careful with this one. A peek leaves the buffer on the
547 * list and someone else may run off with it. You must hold
548 * the appropriate locks or have a private queue to do this.
549 *
550 * Returns %NULL for an empty list or a pointer to the head element.
551 * The reference count is not incremented and the reference is therefore
552 * volatile. Use with caution.
553 */
554static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
555{
556 struct sk_buff *list = ((struct sk_buff *)list_)->next;
557 if (list == (struct sk_buff *)list_)
558 list = NULL;
559 return list;
560}
561
562/**
563 * skb_peek_tail
564 * @list_: list to peek at
565 *
566 * Peek an &sk_buff. Unlike most other operations you _MUST_
567 * be careful with this one. A peek leaves the buffer on the
568 * list and someone else may run off with it. You must hold
569 * the appropriate locks or have a private queue to do this.
570 *
571 * Returns %NULL for an empty list or a pointer to the tail element.
572 * The reference count is not incremented and the reference is therefore
573 * volatile. Use with caution.
574 */
575static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
576{
577 struct sk_buff *list = ((struct sk_buff *)list_)->prev;
578 if (list == (struct sk_buff *)list_)
579 list = NULL;
580 return list;
581}
582
583/**
584 * skb_queue_len - get queue length
585 * @list_: list to measure
586 *
587 * Return the length of an &sk_buff queue.
588 */
589static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
590{
591 return list_->qlen;
592}
593
594static inline void skb_queue_head_init(struct sk_buff_head *list)
595{
596 spin_lock_init(&list->lock);
597 list->prev = list->next = (struct sk_buff *)list;
598 list->qlen = 0;
599}
600
601/*
602 * Insert an sk_buff at the start of a list.
603 *
604 * The "__skb_xxxx()" functions are the non-atomic ones that
605 * can only be called with interrupts disabled.
606 */
607
608/**
Stephen Hemminger300ce172005-10-30 13:47:34 -0800609 * __skb_queue_after - queue a buffer at the list head
610 * @list: list to use
611 * @prev: place after this buffer
612 * @newsk: buffer to queue
613 *
614 * Queue a buffer int the middle of a list. This function takes no locks
615 * and you must therefore hold required locks before calling it.
616 *
617 * A buffer cannot be placed on two lists at the same time.
618 */
619static inline void __skb_queue_after(struct sk_buff_head *list,
620 struct sk_buff *prev,
621 struct sk_buff *newsk)
622{
623 struct sk_buff *next;
624 list->qlen++;
625
626 next = prev->next;
627 newsk->next = next;
628 newsk->prev = prev;
629 next->prev = prev->next = newsk;
630}
631
632/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 * __skb_queue_head - queue a buffer at the list head
634 * @list: list to use
635 * @newsk: buffer to queue
636 *
637 * Queue a buffer at the start of a list. This function takes no locks
638 * and you must therefore hold required locks before calling it.
639 *
640 * A buffer cannot be placed on two lists at the same time.
641 */
642extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
643static inline void __skb_queue_head(struct sk_buff_head *list,
644 struct sk_buff *newsk)
645{
Stephen Hemminger300ce172005-10-30 13:47:34 -0800646 __skb_queue_after(list, (struct sk_buff *)list, newsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647}
648
649/**
650 * __skb_queue_tail - queue a buffer at the list tail
651 * @list: list to use
652 * @newsk: buffer to queue
653 *
654 * Queue a buffer at the end of a list. This function takes no locks
655 * and you must therefore hold required locks before calling it.
656 *
657 * A buffer cannot be placed on two lists at the same time.
658 */
659extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
660static inline void __skb_queue_tail(struct sk_buff_head *list,
661 struct sk_buff *newsk)
662{
663 struct sk_buff *prev, *next;
664
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 list->qlen++;
666 next = (struct sk_buff *)list;
667 prev = next->prev;
668 newsk->next = next;
669 newsk->prev = prev;
670 next->prev = prev->next = newsk;
671}
672
673
674/**
675 * __skb_dequeue - remove from the head of the queue
676 * @list: list to dequeue from
677 *
678 * Remove the head of the list. This function does not take any locks
679 * so must be used with appropriate locks held only. The head item is
680 * returned or %NULL if the list is empty.
681 */
682extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
683static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
684{
685 struct sk_buff *next, *prev, *result;
686
687 prev = (struct sk_buff *) list;
688 next = prev->next;
689 result = NULL;
690 if (next != prev) {
691 result = next;
692 next = next->next;
693 list->qlen--;
694 next->prev = prev;
695 prev->next = next;
696 result->next = result->prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 }
698 return result;
699}
700
701
702/*
703 * Insert a packet on a list.
704 */
David S. Miller8728b832005-08-09 19:25:21 -0700705extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706static inline void __skb_insert(struct sk_buff *newsk,
707 struct sk_buff *prev, struct sk_buff *next,
708 struct sk_buff_head *list)
709{
710 newsk->next = next;
711 newsk->prev = prev;
712 next->prev = prev->next = newsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 list->qlen++;
714}
715
716/*
717 * Place a packet after a given packet in a list.
718 */
David S. Miller8728b832005-08-09 19:25:21 -0700719extern void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
720static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721{
David S. Miller8728b832005-08-09 19:25:21 -0700722 __skb_insert(newsk, old, old->next, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723}
724
725/*
726 * remove sk_buff from list. _Must_ be called atomically, and with
727 * the list known..
728 */
David S. Miller8728b832005-08-09 19:25:21 -0700729extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
731{
732 struct sk_buff *next, *prev;
733
734 list->qlen--;
735 next = skb->next;
736 prev = skb->prev;
737 skb->next = skb->prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 next->prev = prev;
739 prev->next = next;
740}
741
742
743/* XXX: more streamlined implementation */
744
745/**
746 * __skb_dequeue_tail - remove from the tail of the queue
747 * @list: list to dequeue from
748 *
749 * Remove the tail of the list. This function does not take any locks
750 * so must be used with appropriate locks held only. The tail item is
751 * returned or %NULL if the list is empty.
752 */
753extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
754static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
755{
756 struct sk_buff *skb = skb_peek_tail(list);
757 if (skb)
758 __skb_unlink(skb, list);
759 return skb;
760}
761
762
763static inline int skb_is_nonlinear(const struct sk_buff *skb)
764{
765 return skb->data_len;
766}
767
768static inline unsigned int skb_headlen(const struct sk_buff *skb)
769{
770 return skb->len - skb->data_len;
771}
772
773static inline int skb_pagelen(const struct sk_buff *skb)
774{
775 int i, len = 0;
776
777 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
778 len += skb_shinfo(skb)->frags[i].size;
779 return len + skb_headlen(skb);
780}
781
782static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
783 struct page *page, int off, int size)
784{
785 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
786
787 frag->page = page;
788 frag->page_offset = off;
789 frag->size = size;
790 skb_shinfo(skb)->nr_frags = i + 1;
791}
792
793#define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
794#define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list)
795#define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
796
797/*
798 * Add data to an sk_buff
799 */
800static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
801{
802 unsigned char *tmp = skb->tail;
803 SKB_LINEAR_ASSERT(skb);
804 skb->tail += len;
805 skb->len += len;
806 return tmp;
807}
808
809/**
810 * skb_put - add data to 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. If this would
815 * exceed the total buffer size the kernel will panic. A pointer to the
816 * first byte of the extra data is returned.
817 */
818static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
819{
820 unsigned char *tmp = skb->tail;
821 SKB_LINEAR_ASSERT(skb);
822 skb->tail += len;
823 skb->len += len;
824 if (unlikely(skb->tail>skb->end))
825 skb_over_panic(skb, len, current_text_addr());
826 return tmp;
827}
828
829static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
830{
831 skb->data -= len;
832 skb->len += len;
833 return skb->data;
834}
835
836/**
837 * skb_push - add data to the start of a buffer
838 * @skb: buffer to use
839 * @len: amount of data to add
840 *
841 * This function extends the used data area of the buffer at the buffer
842 * start. If this would exceed the total buffer headroom the kernel will
843 * panic. A pointer to the first byte of the extra data is returned.
844 */
845static inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
846{
847 skb->data -= len;
848 skb->len += len;
849 if (unlikely(skb->data<skb->head))
850 skb_under_panic(skb, len, current_text_addr());
851 return skb->data;
852}
853
854static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
855{
856 skb->len -= len;
857 BUG_ON(skb->len < skb->data_len);
858 return skb->data += len;
859}
860
861/**
862 * skb_pull - remove data from the start of a buffer
863 * @skb: buffer to use
864 * @len: amount of data to remove
865 *
866 * This function removes data from the start of a buffer, returning
867 * the memory to the headroom. A pointer to the next data in the buffer
868 * is returned. Once the data has been pulled future pushes will overwrite
869 * the old data.
870 */
871static inline unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
872{
873 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
874}
875
876extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
877
878static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
879{
880 if (len > skb_headlen(skb) &&
881 !__pskb_pull_tail(skb, len-skb_headlen(skb)))
882 return NULL;
883 skb->len -= len;
884 return skb->data += len;
885}
886
887static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
888{
889 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
890}
891
892static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
893{
894 if (likely(len <= skb_headlen(skb)))
895 return 1;
896 if (unlikely(len > skb->len))
897 return 0;
898 return __pskb_pull_tail(skb, len-skb_headlen(skb)) != NULL;
899}
900
901/**
902 * skb_headroom - bytes at buffer head
903 * @skb: buffer to check
904 *
905 * Return the number of bytes of free space at the head of an &sk_buff.
906 */
907static inline int skb_headroom(const struct sk_buff *skb)
908{
909 return skb->data - skb->head;
910}
911
912/**
913 * skb_tailroom - bytes at buffer end
914 * @skb: buffer to check
915 *
916 * Return the number of bytes of free space at the tail of an sk_buff
917 */
918static inline int skb_tailroom(const struct sk_buff *skb)
919{
920 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
921}
922
923/**
924 * skb_reserve - adjust headroom
925 * @skb: buffer to alter
926 * @len: bytes to move
927 *
928 * Increase the headroom of an empty &sk_buff by reducing the tail
929 * room. This is only allowed for an empty buffer.
930 */
931static inline void skb_reserve(struct sk_buff *skb, unsigned int len)
932{
933 skb->data += len;
934 skb->tail += len;
935}
936
937/*
938 * CPUs often take a performance hit when accessing unaligned memory
939 * locations. The actual performance hit varies, it can be small if the
940 * hardware handles it or large if we have to take an exception and fix it
941 * in software.
942 *
943 * Since an ethernet header is 14 bytes network drivers often end up with
944 * the IP header at an unaligned offset. The IP header can be aligned by
945 * shifting the start of the packet by 2 bytes. Drivers should do this
946 * with:
947 *
948 * skb_reserve(NET_IP_ALIGN);
949 *
950 * The downside to this alignment of the IP header is that the DMA is now
951 * unaligned. On some architectures the cost of an unaligned DMA is high
952 * and this cost outweighs the gains made by aligning the IP header.
953 *
954 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
955 * to be overridden.
956 */
957#ifndef NET_IP_ALIGN
958#define NET_IP_ALIGN 2
959#endif
960
961extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
962
963static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
964{
965 if (!skb->data_len) {
966 skb->len = len;
967 skb->tail = skb->data + len;
968 } else
969 ___pskb_trim(skb, len, 0);
970}
971
972/**
973 * skb_trim - remove end from a buffer
974 * @skb: buffer to alter
975 * @len: new length
976 *
977 * Cut the length of a buffer down by removing data from the tail. If
978 * the buffer is already under the length specified it is not modified.
979 */
980static inline void skb_trim(struct sk_buff *skb, unsigned int len)
981{
982 if (skb->len > len)
983 __skb_trim(skb, len);
984}
985
986
987static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
988{
989 if (!skb->data_len) {
990 skb->len = len;
991 skb->tail = skb->data+len;
992 return 0;
993 }
994 return ___pskb_trim(skb, len, 1);
995}
996
997static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
998{
999 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1000}
1001
1002/**
1003 * skb_orphan - orphan a buffer
1004 * @skb: buffer to orphan
1005 *
1006 * If a buffer currently has an owner then we call the owner's
1007 * destructor function and make the @skb unowned. The buffer continues
1008 * to exist but is no longer charged to its former owner.
1009 */
1010static inline void skb_orphan(struct sk_buff *skb)
1011{
1012 if (skb->destructor)
1013 skb->destructor(skb);
1014 skb->destructor = NULL;
1015 skb->sk = NULL;
1016}
1017
1018/**
1019 * __skb_queue_purge - empty a list
1020 * @list: list to empty
1021 *
1022 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1023 * the list and one reference dropped. This function does not take the
1024 * list lock and the caller must hold the relevant locks to use it.
1025 */
1026extern void skb_queue_purge(struct sk_buff_head *list);
1027static inline void __skb_queue_purge(struct sk_buff_head *list)
1028{
1029 struct sk_buff *skb;
1030 while ((skb = __skb_dequeue(list)) != NULL)
1031 kfree_skb(skb);
1032}
1033
Pavel Pisa4dc3b162005-05-01 08:59:25 -07001034#ifndef CONFIG_HAVE_ARCH_DEV_ALLOC_SKB
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035/**
1036 * __dev_alloc_skb - allocate an skbuff for sending
1037 * @length: length to allocate
1038 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1039 *
1040 * Allocate a new &sk_buff and assign it a usage count of one. The
1041 * buffer has unspecified headroom built in. Users should allocate
1042 * the headroom they think they need without accounting for the
1043 * built in space. The built in space is used for optimisations.
1044 *
1045 * %NULL is returned in there is no free memory.
1046 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
Al Virodd0fc662005-10-07 07:46:04 +01001048 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049{
1050 struct sk_buff *skb = alloc_skb(length + 16, gfp_mask);
1051 if (likely(skb))
1052 skb_reserve(skb, 16);
1053 return skb;
1054}
1055#else
1056extern struct sk_buff *__dev_alloc_skb(unsigned int length, int gfp_mask);
1057#endif
1058
1059/**
1060 * dev_alloc_skb - allocate an skbuff for sending
1061 * @length: length to allocate
1062 *
1063 * Allocate a new &sk_buff and assign it a usage count of one. The
1064 * buffer has unspecified headroom built in. Users should allocate
1065 * the headroom they think they need without accounting for the
1066 * built in space. The built in space is used for optimisations.
1067 *
1068 * %NULL is returned in there is no free memory. Although this function
1069 * allocates memory it can be called from an interrupt.
1070 */
1071static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1072{
1073 return __dev_alloc_skb(length, GFP_ATOMIC);
1074}
1075
1076/**
1077 * skb_cow - copy header of skb when it is required
1078 * @skb: buffer to cow
1079 * @headroom: needed headroom
1080 *
1081 * If the skb passed lacks sufficient headroom or its data part
1082 * is shared, data is reallocated. If reallocation fails, an error
1083 * is returned and original skb is not changed.
1084 *
1085 * The result is skb with writable area skb->head...skb->tail
1086 * and at least @headroom of space at head.
1087 */
1088static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1089{
1090 int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb);
1091
1092 if (delta < 0)
1093 delta = 0;
1094
1095 if (delta || skb_cloned(skb))
1096 return pskb_expand_head(skb, (delta + 15) & ~15, 0, GFP_ATOMIC);
1097 return 0;
1098}
1099
1100/**
1101 * skb_padto - pad an skbuff up to a minimal size
1102 * @skb: buffer to pad
1103 * @len: minimal length
1104 *
1105 * Pads up a buffer to ensure the trailing bytes exist and are
1106 * blanked. If the buffer already contains sufficient data it
1107 * is untouched. Returns the buffer, which may be a replacement
1108 * for the original, or NULL for out of memory - in which case
1109 * the original buffer is still freed.
1110 */
1111
1112static inline struct sk_buff *skb_padto(struct sk_buff *skb, unsigned int len)
1113{
1114 unsigned int size = skb->len;
1115 if (likely(size >= len))
1116 return skb;
1117 return skb_pad(skb, len-size);
1118}
1119
1120static inline int skb_add_data(struct sk_buff *skb,
1121 char __user *from, int copy)
1122{
1123 const int off = skb->len;
1124
1125 if (skb->ip_summed == CHECKSUM_NONE) {
1126 int err = 0;
1127 unsigned int csum = csum_and_copy_from_user(from,
1128 skb_put(skb, copy),
1129 copy, 0, &err);
1130 if (!err) {
1131 skb->csum = csum_block_add(skb->csum, csum, off);
1132 return 0;
1133 }
1134 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1135 return 0;
1136
1137 __skb_trim(skb, off);
1138 return -EFAULT;
1139}
1140
1141static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1142 struct page *page, int off)
1143{
1144 if (i) {
1145 struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1146
1147 return page == frag->page &&
1148 off == frag->page_offset + frag->size;
1149 }
1150 return 0;
1151}
1152
1153/**
1154 * skb_linearize - convert paged skb to linear one
1155 * @skb: buffer to linarize
1156 * @gfp: allocation mode
1157 *
1158 * If there is no free memory -ENOMEM is returned, otherwise zero
1159 * is returned and the old skb data released.
1160 */
Al Virodd0fc662005-10-07 07:46:04 +01001161extern int __skb_linearize(struct sk_buff *skb, gfp_t gfp);
1162static inline int skb_linearize(struct sk_buff *skb, gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163{
1164 return __skb_linearize(skb, gfp);
1165}
1166
1167/**
1168 * skb_postpull_rcsum - update checksum for received skb after pull
1169 * @skb: buffer to update
1170 * @start: start of data before pull
1171 * @len: length of data pulled
1172 *
1173 * After doing a pull on a received packet, you need to call this to
1174 * update the CHECKSUM_HW checksum, or set ip_summed to CHECKSUM_NONE
1175 * so that it can be recomputed from scratch.
1176 */
1177
1178static inline void skb_postpull_rcsum(struct sk_buff *skb,
1179 const void *start, int len)
1180{
1181 if (skb->ip_summed == CHECKSUM_HW)
1182 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1183}
1184
1185/**
1186 * pskb_trim_rcsum - trim received skb and update checksum
1187 * @skb: buffer to trim
1188 * @len: new length
1189 *
1190 * This is exactly the same as pskb_trim except that it ensures the
1191 * checksum of received packets are still valid after the operation.
1192 */
1193
1194static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1195{
Stephen Hemminger0e4e4222005-09-08 12:32:03 -07001196 if (likely(len >= skb->len))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 return 0;
1198 if (skb->ip_summed == CHECKSUM_HW)
1199 skb->ip_summed = CHECKSUM_NONE;
1200 return __pskb_trim(skb, len);
1201}
1202
1203static inline void *kmap_skb_frag(const skb_frag_t *frag)
1204{
1205#ifdef CONFIG_HIGHMEM
1206 BUG_ON(in_irq());
1207
1208 local_bh_disable();
1209#endif
1210 return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ);
1211}
1212
1213static inline void kunmap_skb_frag(void *vaddr)
1214{
1215 kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
1216#ifdef CONFIG_HIGHMEM
1217 local_bh_enable();
1218#endif
1219}
1220
1221#define skb_queue_walk(queue, skb) \
1222 for (skb = (queue)->next; \
1223 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1224 skb = skb->next)
1225
Stephen Hemminger300ce172005-10-30 13:47:34 -08001226#define skb_queue_reverse_walk(queue, skb) \
1227 for (skb = (queue)->prev; \
1228 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1229 skb = skb->prev)
1230
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231
1232extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
1233 int noblock, int *err);
1234extern unsigned int datagram_poll(struct file *file, struct socket *sock,
1235 struct poll_table_struct *wait);
1236extern int skb_copy_datagram_iovec(const struct sk_buff *from,
1237 int offset, struct iovec *to,
1238 int size);
Herbert Xufb286bb2005-11-10 13:01:24 -08001239extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 int hlen,
1241 struct iovec *iov);
1242extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
1243extern unsigned int skb_checksum(const struct sk_buff *skb, int offset,
1244 int len, unsigned int csum);
1245extern int skb_copy_bits(const struct sk_buff *skb, int offset,
1246 void *to, int len);
Herbert Xu357b40a2005-04-19 22:30:14 -07001247extern int skb_store_bits(const struct sk_buff *skb, int offset,
1248 void *from, int len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249extern unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb,
1250 int offset, u8 *to, int len,
1251 unsigned int csum);
1252extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
1253extern void skb_split(struct sk_buff *skb,
1254 struct sk_buff *skb1, const u32 len);
1255
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -03001256extern void skb_release_data(struct sk_buff *skb);
1257
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
1259 int len, void *buffer)
1260{
1261 int hlen = skb_headlen(skb);
1262
Patrick McHardy55820ee2005-07-05 14:08:10 -07001263 if (hlen - offset >= len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 return skb->data + offset;
1265
1266 if (skb_copy_bits(skb, offset, buffer, len) < 0)
1267 return NULL;
1268
1269 return buffer;
1270}
1271
1272extern void skb_init(void);
1273extern void skb_add_mtu(int mtu);
1274
Patrick McHardya61bbcf2005-08-14 17:24:31 -07001275/**
1276 * skb_get_timestamp - get timestamp from a skb
1277 * @skb: skb to get stamp from
1278 * @stamp: pointer to struct timeval to store stamp in
1279 *
1280 * Timestamps are stored in the skb as offsets to a base timestamp.
1281 * This function converts the offset back to a struct timeval and stores
1282 * it in stamp.
1283 */
Stephen Hemmingerf2c38392005-09-06 15:48:03 -07001284static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *stamp)
Patrick McHardya61bbcf2005-08-14 17:24:31 -07001285{
1286 stamp->tv_sec = skb->tstamp.off_sec;
1287 stamp->tv_usec = skb->tstamp.off_usec;
Patrick McHardya61bbcf2005-08-14 17:24:31 -07001288}
1289
1290/**
1291 * skb_set_timestamp - set timestamp of a skb
1292 * @skb: skb to set stamp of
1293 * @stamp: pointer to struct timeval to get stamp from
1294 *
1295 * Timestamps are stored in the skb as offsets to a base timestamp.
1296 * This function converts a struct timeval to an offset and stores
1297 * it in the skb.
1298 */
Stephen Hemmingerf2c38392005-09-06 15:48:03 -07001299static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp)
Patrick McHardya61bbcf2005-08-14 17:24:31 -07001300{
Herbert Xu325ed822005-10-03 13:57:23 -07001301 skb->tstamp.off_sec = stamp->tv_sec;
1302 skb->tstamp.off_usec = stamp->tv_usec;
Patrick McHardya61bbcf2005-08-14 17:24:31 -07001303}
1304
1305extern void __net_timestamp(struct sk_buff *skb);
1306
Herbert Xufb286bb2005-11-10 13:01:24 -08001307extern unsigned int __skb_checksum_complete(struct sk_buff *skb);
1308
1309/**
1310 * skb_checksum_complete - Calculate checksum of an entire packet
1311 * @skb: packet to process
1312 *
1313 * This function calculates the checksum over the entire packet plus
1314 * the value of skb->csum. The latter can be used to supply the
1315 * checksum of a pseudo header as used by TCP/UDP. It returns the
1316 * checksum.
1317 *
1318 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
1319 * this function can be used to verify that checksum on received
1320 * packets. In that case the function should return zero if the
1321 * checksum is correct. In particular, this function will return zero
1322 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
1323 * hardware has already verified the correctness of the checksum.
1324 */
1325static inline unsigned int skb_checksum_complete(struct sk_buff *skb)
1326{
1327 return skb->ip_summed != CHECKSUM_UNNECESSARY &&
1328 __skb_checksum_complete(skb);
1329}
1330
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331#ifdef CONFIG_NETFILTER
1332static inline void nf_conntrack_put(struct nf_conntrack *nfct)
1333{
1334 if (nfct && atomic_dec_and_test(&nfct->use))
1335 nfct->destroy(nfct);
1336}
1337static inline void nf_conntrack_get(struct nf_conntrack *nfct)
1338{
1339 if (nfct)
1340 atomic_inc(&nfct->use);
1341}
Yasuyuki Kozakai9fb9cbb2005-11-09 16:38:16 -08001342#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1343static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
1344{
1345 if (skb)
1346 atomic_inc(&skb->users);
1347}
1348static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
1349{
1350 if (skb)
1351 kfree_skb(skb);
1352}
1353#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354static inline void nf_reset(struct sk_buff *skb)
1355{
1356 nf_conntrack_put(skb->nfct);
1357 skb->nfct = NULL;
Yasuyuki Kozakai9fb9cbb2005-11-09 16:38:16 -08001358#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1359 nf_conntrack_put_reasm(skb->nfct_reasm);
1360 skb->nfct_reasm = NULL;
1361#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362}
1363
1364#ifdef CONFIG_BRIDGE_NETFILTER
1365static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
1366{
1367 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
1368 kfree(nf_bridge);
1369}
1370static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
1371{
1372 if (nf_bridge)
1373 atomic_inc(&nf_bridge->use);
1374}
1375#endif /* CONFIG_BRIDGE_NETFILTER */
1376#else /* CONFIG_NETFILTER */
1377static inline void nf_reset(struct sk_buff *skb) {}
1378#endif /* CONFIG_NETFILTER */
1379
1380#endif /* __KERNEL__ */
1381#endif /* _LINUX_SKBUFF_H */