aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/skbuff.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h1253
1 files changed, 1253 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
new file mode 100644
index 000000000000..aa35797ebfbf
--- /dev/null
+++ b/include/linux/skbuff.h
@@ -0,0 +1,1253 @@
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>
30#include <net/checksum.h>
31
32#define HAVE_ALLOC_SKB /* For the drivers to know */
33#define HAVE_ALIGNABLE_SKB /* Ditto 8) */
34#define SLAB_SKB /* Slabified skbuffs */
35
36#define CHECKSUM_NONE 0
37#define CHECKSUM_HW 1
38#define CHECKSUM_UNNECESSARY 2
39
40#define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
41 ~(SMP_CACHE_BYTES - 1))
42#define SKB_MAX_ORDER(X, ORDER) (((PAGE_SIZE << (ORDER)) - (X) - \
43 sizeof(struct skb_shared_info)) & \
44 ~(SMP_CACHE_BYTES - 1))
45#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
46#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
47
48/* A. Checksumming of received packets by device.
49 *
50 * NONE: device failed to checksum this packet.
51 * skb->csum is undefined.
52 *
53 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
54 * skb->csum is undefined.
55 * It is bad option, but, unfortunately, many of vendors do this.
56 * Apparently with secret goal to sell you new device, when you
57 * will add new protocol to your host. F.e. IPv6. 8)
58 *
59 * HW: the most generic way. Device supplied checksum of _all_
60 * the packet as seen by netif_rx in skb->csum.
61 * NOTE: Even if device supports only some protocols, but
62 * is able to produce some skb->csum, it MUST use HW,
63 * not UNNECESSARY.
64 *
65 * B. Checksumming on output.
66 *
67 * NONE: skb is checksummed by protocol or csum is not required.
68 *
69 * HW: device is required to csum packet as seen by hard_start_xmit
70 * from skb->h.raw to the end and to record the checksum
71 * at skb->h.raw+skb->csum.
72 *
73 * Device must show its capabilities in dev->features, set
74 * at device setup time.
75 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
76 * everything.
77 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
78 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
79 * TCP/UDP over IPv4. Sigh. Vendors like this
80 * way by an unknown reason. Though, see comment above
81 * about CHECKSUM_UNNECESSARY. 8)
82 *
83 * Any questions? No questions, good. --ANK
84 */
85
86#ifdef __i386__
87#define NET_CALLER(arg) (*(((void **)&arg) - 1))
88#else
89#define NET_CALLER(arg) __builtin_return_address(0)
90#endif
91
92struct net_device;
93
94#ifdef CONFIG_NETFILTER
95struct nf_conntrack {
96 atomic_t use;
97 void (*destroy)(struct nf_conntrack *);
98};
99
100#ifdef CONFIG_BRIDGE_NETFILTER
101struct nf_bridge_info {
102 atomic_t use;
103 struct net_device *physindev;
104 struct net_device *physoutdev;
105#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
106 struct net_device *netoutdev;
107#endif
108 unsigned int mask;
109 unsigned long data[32 / sizeof(unsigned long)];
110};
111#endif
112
113#endif
114
115struct sk_buff_head {
116 /* These two members must be first. */
117 struct sk_buff *next;
118 struct sk_buff *prev;
119
120 __u32 qlen;
121 spinlock_t lock;
122};
123
124struct sk_buff;
125
126/* To allow 64K frame to be packed as single skb without frag_list */
127#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
128
129typedef struct skb_frag_struct skb_frag_t;
130
131struct skb_frag_struct {
132 struct page *page;
133 __u16 page_offset;
134 __u16 size;
135};
136
137/* This data is invariant across clones and lives at
138 * the end of the header data, ie. at skb->end.
139 */
140struct skb_shared_info {
141 atomic_t dataref;
142 unsigned int nr_frags;
143 unsigned short tso_size;
144 unsigned short tso_segs;
145 struct sk_buff *frag_list;
146 skb_frag_t frags[MAX_SKB_FRAGS];
147};
148
149/* We divide dataref into two halves. The higher 16 bits hold references
150 * to the payload part of skb->data. The lower 16 bits hold references to
151 * the entire skb->data. It is up to the users of the skb to agree on
152 * where the payload starts.
153 *
154 * All users must obey the rule that the skb->data reference count must be
155 * greater than or equal to the payload reference count.
156 *
157 * Holding a reference to the payload part means that the user does not
158 * care about modifications to the header part of skb->data.
159 */
160#define SKB_DATAREF_SHIFT 16
161#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
162
163/**
164 * struct sk_buff - socket buffer
165 * @next: Next buffer in list
166 * @prev: Previous buffer in list
167 * @list: List we are on
168 * @sk: Socket we are owned by
169 * @stamp: Time we arrived
170 * @dev: Device we arrived on/are leaving by
171 * @input_dev: Device we arrived on
172 * @real_dev: The real device we are using
173 * @h: Transport layer header
174 * @nh: Network layer header
175 * @mac: Link layer header
176 * @dst: FIXME: Describe this field
177 * @cb: Control buffer. Free for use by every layer. Put private vars here
178 * @len: Length of actual data
179 * @data_len: Data length
180 * @mac_len: Length of link layer header
181 * @csum: Checksum
182 * @__unused: Dead field, may be reused
183 * @cloned: Head may be cloned (check refcnt to be sure)
184 * @nohdr: Payload reference only, must not modify header
185 * @pkt_type: Packet class
186 * @ip_summed: Driver fed us an IP checksum
187 * @priority: Packet queueing priority
188 * @users: User count - see {datagram,tcp}.c
189 * @protocol: Packet protocol from driver
190 * @security: Security level of packet
191 * @truesize: Buffer size
192 * @head: Head of buffer
193 * @data: Data head pointer
194 * @tail: Tail pointer
195 * @end: End pointer
196 * @destructor: Destruct function
197 * @nfmark: Can be used for communication between hooks
198 * @nfcache: Cache info
199 * @nfct: Associated connection, if any
200 * @nfctinfo: Relationship of this skb to the connection
201 * @nf_debug: Netfilter debugging
202 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
203 * @private: Data which is private to the HIPPI implementation
204 * @tc_index: Traffic control index
205 * @tc_verd: traffic control verdict
206 * @tc_classid: traffic control classid
207 */
208
209struct sk_buff {
210 /* These two members must be first. */
211 struct sk_buff *next;
212 struct sk_buff *prev;
213
214 struct sk_buff_head *list;
215 struct sock *sk;
216 struct timeval stamp;
217 struct net_device *dev;
218 struct net_device *input_dev;
219 struct net_device *real_dev;
220
221 union {
222 struct tcphdr *th;
223 struct udphdr *uh;
224 struct icmphdr *icmph;
225 struct igmphdr *igmph;
226 struct iphdr *ipiph;
227 struct ipv6hdr *ipv6h;
228 unsigned char *raw;
229 } h;
230
231 union {
232 struct iphdr *iph;
233 struct ipv6hdr *ipv6h;
234 struct arphdr *arph;
235 unsigned char *raw;
236 } nh;
237
238 union {
239 unsigned char *raw;
240 } mac;
241
242 struct dst_entry *dst;
243 struct sec_path *sp;
244
245 /*
246 * This is the control buffer. It is free to use for every
247 * layer. Please put your private variables there. If you
248 * want to keep them across layers you have to do a skb_clone()
249 * first. This is owned by whoever has the skb queued ATM.
250 */
251 char cb[40];
252
253 unsigned int len,
254 data_len,
255 mac_len,
256 csum;
257 unsigned char local_df,
258 cloned:1,
259 nohdr:1,
260 pkt_type,
261 ip_summed;
262 __u32 priority;
263 unsigned short protocol,
264 security;
265
266 void (*destructor)(struct sk_buff *skb);
267#ifdef CONFIG_NETFILTER
268 unsigned long nfmark;
269 __u32 nfcache;
270 __u32 nfctinfo;
271 struct nf_conntrack *nfct;
272#ifdef CONFIG_NETFILTER_DEBUG
273 unsigned int nf_debug;
274#endif
275#ifdef CONFIG_BRIDGE_NETFILTER
276 struct nf_bridge_info *nf_bridge;
277#endif
278#endif /* CONFIG_NETFILTER */
279#if defined(CONFIG_HIPPI)
280 union {
281 __u32 ifield;
282 } private;
283#endif
284#ifdef CONFIG_NET_SCHED
285 __u32 tc_index; /* traffic control index */
286#ifdef CONFIG_NET_CLS_ACT
287 __u32 tc_verd; /* traffic control verdict */
288 __u32 tc_classid; /* traffic control classid */
289#endif
290
291#endif
292
293
294 /* These elements must be at the end, see alloc_skb() for details. */
295 unsigned int truesize;
296 atomic_t users;
297 unsigned char *head,
298 *data,
299 *tail,
300 *end;
301};
302
303#ifdef __KERNEL__
304/*
305 * Handling routines are only of interest to the kernel
306 */
307#include <linux/slab.h>
308
309#include <asm/system.h>
310
311extern void __kfree_skb(struct sk_buff *skb);
312extern struct sk_buff *alloc_skb(unsigned int size, int priority);
313extern struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
314 unsigned int size, int priority);
315extern void kfree_skbmem(struct sk_buff *skb);
316extern struct sk_buff *skb_clone(struct sk_buff *skb, int priority);
317extern struct sk_buff *skb_copy(const struct sk_buff *skb, int priority);
318extern struct sk_buff *pskb_copy(struct sk_buff *skb, int gfp_mask);
319extern int pskb_expand_head(struct sk_buff *skb,
320 int nhead, int ntail, int gfp_mask);
321extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
322 unsigned int headroom);
323extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
324 int newheadroom, int newtailroom,
325 int priority);
326extern struct sk_buff * skb_pad(struct sk_buff *skb, int pad);
327#define dev_kfree_skb(a) kfree_skb(a)
328extern void skb_over_panic(struct sk_buff *skb, int len,
329 void *here);
330extern void skb_under_panic(struct sk_buff *skb, int len,
331 void *here);
332
333/* Internal */
334#define skb_shinfo(SKB) ((struct skb_shared_info *)((SKB)->end))
335
336/**
337 * skb_queue_empty - check if a queue is empty
338 * @list: queue head
339 *
340 * Returns true if the queue is empty, false otherwise.
341 */
342static inline int skb_queue_empty(const struct sk_buff_head *list)
343{
344 return list->next == (struct sk_buff *)list;
345}
346
347/**
348 * skb_get - reference buffer
349 * @skb: buffer to reference
350 *
351 * Makes another reference to a socket buffer and returns a pointer
352 * to the buffer.
353 */
354static inline struct sk_buff *skb_get(struct sk_buff *skb)
355{
356 atomic_inc(&skb->users);
357 return skb;
358}
359
360/*
361 * If users == 1, we are the only owner and are can avoid redundant
362 * atomic change.
363 */
364
365/**
366 * kfree_skb - free an sk_buff
367 * @skb: buffer to free
368 *
369 * Drop a reference to the buffer and free it if the usage count has
370 * hit zero.
371 */
372static inline void kfree_skb(struct sk_buff *skb)
373{
374 if (likely(atomic_read(&skb->users) == 1))
375 smp_rmb();
376 else if (likely(!atomic_dec_and_test(&skb->users)))
377 return;
378 __kfree_skb(skb);
379}
380
381/**
382 * skb_cloned - is the buffer a clone
383 * @skb: buffer to check
384 *
385 * Returns true if the buffer was generated with skb_clone() and is
386 * one of multiple shared copies of the buffer. Cloned buffers are
387 * shared data so must not be written to under normal circumstances.
388 */
389static inline int skb_cloned(const struct sk_buff *skb)
390{
391 return skb->cloned &&
392 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
393}
394
395/**
396 * skb_header_cloned - is the header a clone
397 * @skb: buffer to check
398 *
399 * Returns true if modifying the header part of the buffer requires
400 * the data to be copied.
401 */
402static inline int skb_header_cloned(const struct sk_buff *skb)
403{
404 int dataref;
405
406 if (!skb->cloned)
407 return 0;
408
409 dataref = atomic_read(&skb_shinfo(skb)->dataref);
410 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
411 return dataref != 1;
412}
413
414/**
415 * skb_header_release - release reference to header
416 * @skb: buffer to operate on
417 *
418 * Drop a reference to the header part of the buffer. This is done
419 * by acquiring a payload reference. You must not read from the header
420 * part of skb->data after this.
421 */
422static inline void skb_header_release(struct sk_buff *skb)
423{
424 BUG_ON(skb->nohdr);
425 skb->nohdr = 1;
426 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
427}
428
429/**
430 * skb_shared - is the buffer shared
431 * @skb: buffer to check
432 *
433 * Returns true if more than one person has a reference to this
434 * buffer.
435 */
436static inline int skb_shared(const struct sk_buff *skb)
437{
438 return atomic_read(&skb->users) != 1;
439}
440
441/**
442 * skb_share_check - check if buffer is shared and if so clone it
443 * @skb: buffer to check
444 * @pri: priority for memory allocation
445 *
446 * If the buffer is shared the buffer is cloned and the old copy
447 * drops a reference. A new clone with a single reference is returned.
448 * If the buffer is not shared the original buffer is returned. When
449 * being called from interrupt status or with spinlocks held pri must
450 * be GFP_ATOMIC.
451 *
452 * NULL is returned on a memory allocation failure.
453 */
454static inline struct sk_buff *skb_share_check(struct sk_buff *skb, int pri)
455{
456 might_sleep_if(pri & __GFP_WAIT);
457 if (skb_shared(skb)) {
458 struct sk_buff *nskb = skb_clone(skb, pri);
459 kfree_skb(skb);
460 skb = nskb;
461 }
462 return skb;
463}
464
465/*
466 * Copy shared buffers into a new sk_buff. We effectively do COW on
467 * packets to handle cases where we have a local reader and forward
468 * and a couple of other messy ones. The normal one is tcpdumping
469 * a packet thats being forwarded.
470 */
471
472/**
473 * skb_unshare - make a copy of a shared buffer
474 * @skb: buffer to check
475 * @pri: priority for memory allocation
476 *
477 * If the socket buffer is a clone then this function creates a new
478 * copy of the data, drops a reference count on the old copy and returns
479 * the new copy with the reference count at 1. If the buffer is not a clone
480 * the original buffer is returned. When called with a spinlock held or
481 * from interrupt state @pri must be %GFP_ATOMIC
482 *
483 * %NULL is returned on a memory allocation failure.
484 */
485static inline struct sk_buff *skb_unshare(struct sk_buff *skb, int pri)
486{
487 might_sleep_if(pri & __GFP_WAIT);
488 if (skb_cloned(skb)) {
489 struct sk_buff *nskb = skb_copy(skb, pri);
490 kfree_skb(skb); /* Free our shared copy */
491 skb = nskb;
492 }
493 return skb;
494}
495
496/**
497 * skb_peek
498 * @list_: list to peek at
499 *
500 * Peek an &sk_buff. Unlike most other operations you _MUST_
501 * be careful with this one. A peek leaves the buffer on the
502 * list and someone else may run off with it. You must hold
503 * the appropriate locks or have a private queue to do this.
504 *
505 * Returns %NULL for an empty list or a pointer to the head element.
506 * The reference count is not incremented and the reference is therefore
507 * volatile. Use with caution.
508 */
509static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
510{
511 struct sk_buff *list = ((struct sk_buff *)list_)->next;
512 if (list == (struct sk_buff *)list_)
513 list = NULL;
514 return list;
515}
516
517/**
518 * skb_peek_tail
519 * @list_: list to peek at
520 *
521 * Peek an &sk_buff. Unlike most other operations you _MUST_
522 * be careful with this one. A peek leaves the buffer on the
523 * list and someone else may run off with it. You must hold
524 * the appropriate locks or have a private queue to do this.
525 *
526 * Returns %NULL for an empty list or a pointer to the tail element.
527 * The reference count is not incremented and the reference is therefore
528 * volatile. Use with caution.
529 */
530static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
531{
532 struct sk_buff *list = ((struct sk_buff *)list_)->prev;
533 if (list == (struct sk_buff *)list_)
534 list = NULL;
535 return list;
536}
537
538/**
539 * skb_queue_len - get queue length
540 * @list_: list to measure
541 *
542 * Return the length of an &sk_buff queue.
543 */
544static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
545{
546 return list_->qlen;
547}
548
549static inline void skb_queue_head_init(struct sk_buff_head *list)
550{
551 spin_lock_init(&list->lock);
552 list->prev = list->next = (struct sk_buff *)list;
553 list->qlen = 0;
554}
555
556/*
557 * Insert an sk_buff at the start of a list.
558 *
559 * The "__skb_xxxx()" functions are the non-atomic ones that
560 * can only be called with interrupts disabled.
561 */
562
563/**
564 * __skb_queue_head - queue a buffer at the list head
565 * @list: list to use
566 * @newsk: buffer to queue
567 *
568 * Queue a buffer at the start of a list. This function takes no locks
569 * and you must therefore hold required locks before calling it.
570 *
571 * A buffer cannot be placed on two lists at the same time.
572 */
573extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
574static inline void __skb_queue_head(struct sk_buff_head *list,
575 struct sk_buff *newsk)
576{
577 struct sk_buff *prev, *next;
578
579 newsk->list = list;
580 list->qlen++;
581 prev = (struct sk_buff *)list;
582 next = prev->next;
583 newsk->next = next;
584 newsk->prev = prev;
585 next->prev = prev->next = newsk;
586}
587
588/**
589 * __skb_queue_tail - queue a buffer at the list tail
590 * @list: list to use
591 * @newsk: buffer to queue
592 *
593 * Queue a buffer at the end of a list. This function takes no locks
594 * and you must therefore hold required locks before calling it.
595 *
596 * A buffer cannot be placed on two lists at the same time.
597 */
598extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
599static inline void __skb_queue_tail(struct sk_buff_head *list,
600 struct sk_buff *newsk)
601{
602 struct sk_buff *prev, *next;
603
604 newsk->list = list;
605 list->qlen++;
606 next = (struct sk_buff *)list;
607 prev = next->prev;
608 newsk->next = next;
609 newsk->prev = prev;
610 next->prev = prev->next = newsk;
611}
612
613
614/**
615 * __skb_dequeue - remove from the head of the queue
616 * @list: list to dequeue from
617 *
618 * Remove the head of the list. This function does not take any locks
619 * so must be used with appropriate locks held only. The head item is
620 * returned or %NULL if the list is empty.
621 */
622extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
623static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
624{
625 struct sk_buff *next, *prev, *result;
626
627 prev = (struct sk_buff *) list;
628 next = prev->next;
629 result = NULL;
630 if (next != prev) {
631 result = next;
632 next = next->next;
633 list->qlen--;
634 next->prev = prev;
635 prev->next = next;
636 result->next = result->prev = NULL;
637 result->list = NULL;
638 }
639 return result;
640}
641
642
643/*
644 * Insert a packet on a list.
645 */
646extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk);
647static inline void __skb_insert(struct sk_buff *newsk,
648 struct sk_buff *prev, struct sk_buff *next,
649 struct sk_buff_head *list)
650{
651 newsk->next = next;
652 newsk->prev = prev;
653 next->prev = prev->next = newsk;
654 newsk->list = list;
655 list->qlen++;
656}
657
658/*
659 * Place a packet after a given packet in a list.
660 */
661extern void skb_append(struct sk_buff *old, struct sk_buff *newsk);
662static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk)
663{
664 __skb_insert(newsk, old, old->next, old->list);
665}
666
667/*
668 * remove sk_buff from list. _Must_ be called atomically, and with
669 * the list known..
670 */
671extern void skb_unlink(struct sk_buff *skb);
672static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
673{
674 struct sk_buff *next, *prev;
675
676 list->qlen--;
677 next = skb->next;
678 prev = skb->prev;
679 skb->next = skb->prev = NULL;
680 skb->list = NULL;
681 next->prev = prev;
682 prev->next = next;
683}
684
685
686/* XXX: more streamlined implementation */
687
688/**
689 * __skb_dequeue_tail - remove from the tail of the queue
690 * @list: list to dequeue from
691 *
692 * Remove the tail of the list. This function does not take any locks
693 * so must be used with appropriate locks held only. The tail item is
694 * returned or %NULL if the list is empty.
695 */
696extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
697static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
698{
699 struct sk_buff *skb = skb_peek_tail(list);
700 if (skb)
701 __skb_unlink(skb, list);
702 return skb;
703}
704
705
706static inline int skb_is_nonlinear(const struct sk_buff *skb)
707{
708 return skb->data_len;
709}
710
711static inline unsigned int skb_headlen(const struct sk_buff *skb)
712{
713 return skb->len - skb->data_len;
714}
715
716static inline int skb_pagelen(const struct sk_buff *skb)
717{
718 int i, len = 0;
719
720 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
721 len += skb_shinfo(skb)->frags[i].size;
722 return len + skb_headlen(skb);
723}
724
725static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
726 struct page *page, int off, int size)
727{
728 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
729
730 frag->page = page;
731 frag->page_offset = off;
732 frag->size = size;
733 skb_shinfo(skb)->nr_frags = i + 1;
734}
735
736#define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
737#define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list)
738#define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
739
740/*
741 * Add data to an sk_buff
742 */
743static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
744{
745 unsigned char *tmp = skb->tail;
746 SKB_LINEAR_ASSERT(skb);
747 skb->tail += len;
748 skb->len += len;
749 return tmp;
750}
751
752/**
753 * skb_put - add data to a buffer
754 * @skb: buffer to use
755 * @len: amount of data to add
756 *
757 * This function extends the used data area of the buffer. If this would
758 * exceed the total buffer size the kernel will panic. A pointer to the
759 * first byte of the extra data is returned.
760 */
761static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
762{
763 unsigned char *tmp = skb->tail;
764 SKB_LINEAR_ASSERT(skb);
765 skb->tail += len;
766 skb->len += len;
767 if (unlikely(skb->tail>skb->end))
768 skb_over_panic(skb, len, current_text_addr());
769 return tmp;
770}
771
772static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
773{
774 skb->data -= len;
775 skb->len += len;
776 return skb->data;
777}
778
779/**
780 * skb_push - add data to the start of a buffer
781 * @skb: buffer to use
782 * @len: amount of data to add
783 *
784 * This function extends the used data area of the buffer at the buffer
785 * start. If this would exceed the total buffer headroom the kernel will
786 * panic. A pointer to the first byte of the extra data is returned.
787 */
788static inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
789{
790 skb->data -= len;
791 skb->len += len;
792 if (unlikely(skb->data<skb->head))
793 skb_under_panic(skb, len, current_text_addr());
794 return skb->data;
795}
796
797static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
798{
799 skb->len -= len;
800 BUG_ON(skb->len < skb->data_len);
801 return skb->data += len;
802}
803
804/**
805 * skb_pull - remove data from the start of a buffer
806 * @skb: buffer to use
807 * @len: amount of data to remove
808 *
809 * This function removes data from the start of a buffer, returning
810 * the memory to the headroom. A pointer to the next data in the buffer
811 * is returned. Once the data has been pulled future pushes will overwrite
812 * the old data.
813 */
814static inline unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
815{
816 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
817}
818
819extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
820
821static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
822{
823 if (len > skb_headlen(skb) &&
824 !__pskb_pull_tail(skb, len-skb_headlen(skb)))
825 return NULL;
826 skb->len -= len;
827 return skb->data += len;
828}
829
830static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
831{
832 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
833}
834
835static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
836{
837 if (likely(len <= skb_headlen(skb)))
838 return 1;
839 if (unlikely(len > skb->len))
840 return 0;
841 return __pskb_pull_tail(skb, len-skb_headlen(skb)) != NULL;
842}
843
844/**
845 * skb_headroom - bytes at buffer head
846 * @skb: buffer to check
847 *
848 * Return the number of bytes of free space at the head of an &sk_buff.
849 */
850static inline int skb_headroom(const struct sk_buff *skb)
851{
852 return skb->data - skb->head;
853}
854
855/**
856 * skb_tailroom - bytes at buffer end
857 * @skb: buffer to check
858 *
859 * Return the number of bytes of free space at the tail of an sk_buff
860 */
861static inline int skb_tailroom(const struct sk_buff *skb)
862{
863 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
864}
865
866/**
867 * skb_reserve - adjust headroom
868 * @skb: buffer to alter
869 * @len: bytes to move
870 *
871 * Increase the headroom of an empty &sk_buff by reducing the tail
872 * room. This is only allowed for an empty buffer.
873 */
874static inline void skb_reserve(struct sk_buff *skb, unsigned int len)
875{
876 skb->data += len;
877 skb->tail += len;
878}
879
880/*
881 * CPUs often take a performance hit when accessing unaligned memory
882 * locations. The actual performance hit varies, it can be small if the
883 * hardware handles it or large if we have to take an exception and fix it
884 * in software.
885 *
886 * Since an ethernet header is 14 bytes network drivers often end up with
887 * the IP header at an unaligned offset. The IP header can be aligned by
888 * shifting the start of the packet by 2 bytes. Drivers should do this
889 * with:
890 *
891 * skb_reserve(NET_IP_ALIGN);
892 *
893 * The downside to this alignment of the IP header is that the DMA is now
894 * unaligned. On some architectures the cost of an unaligned DMA is high
895 * and this cost outweighs the gains made by aligning the IP header.
896 *
897 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
898 * to be overridden.
899 */
900#ifndef NET_IP_ALIGN
901#define NET_IP_ALIGN 2
902#endif
903
904extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
905
906static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
907{
908 if (!skb->data_len) {
909 skb->len = len;
910 skb->tail = skb->data + len;
911 } else
912 ___pskb_trim(skb, len, 0);
913}
914
915/**
916 * skb_trim - remove end from a buffer
917 * @skb: buffer to alter
918 * @len: new length
919 *
920 * Cut the length of a buffer down by removing data from the tail. If
921 * the buffer is already under the length specified it is not modified.
922 */
923static inline void skb_trim(struct sk_buff *skb, unsigned int len)
924{
925 if (skb->len > len)
926 __skb_trim(skb, len);
927}
928
929
930static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
931{
932 if (!skb->data_len) {
933 skb->len = len;
934 skb->tail = skb->data+len;
935 return 0;
936 }
937 return ___pskb_trim(skb, len, 1);
938}
939
940static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
941{
942 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
943}
944
945/**
946 * skb_orphan - orphan a buffer
947 * @skb: buffer to orphan
948 *
949 * If a buffer currently has an owner then we call the owner's
950 * destructor function and make the @skb unowned. The buffer continues
951 * to exist but is no longer charged to its former owner.
952 */
953static inline void skb_orphan(struct sk_buff *skb)
954{
955 if (skb->destructor)
956 skb->destructor(skb);
957 skb->destructor = NULL;
958 skb->sk = NULL;
959}
960
961/**
962 * __skb_queue_purge - empty a list
963 * @list: list to empty
964 *
965 * Delete all buffers on an &sk_buff list. Each buffer is removed from
966 * the list and one reference dropped. This function does not take the
967 * list lock and the caller must hold the relevant locks to use it.
968 */
969extern void skb_queue_purge(struct sk_buff_head *list);
970static inline void __skb_queue_purge(struct sk_buff_head *list)
971{
972 struct sk_buff *skb;
973 while ((skb = __skb_dequeue(list)) != NULL)
974 kfree_skb(skb);
975}
976
977/**
978 * __dev_alloc_skb - allocate an skbuff for sending
979 * @length: length to allocate
980 * @gfp_mask: get_free_pages mask, passed to alloc_skb
981 *
982 * Allocate a new &sk_buff and assign it a usage count of one. The
983 * buffer has unspecified headroom built in. Users should allocate
984 * the headroom they think they need without accounting for the
985 * built in space. The built in space is used for optimisations.
986 *
987 * %NULL is returned in there is no free memory.
988 */
989#ifndef CONFIG_HAVE_ARCH_DEV_ALLOC_SKB
990static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
991 int gfp_mask)
992{
993 struct sk_buff *skb = alloc_skb(length + 16, gfp_mask);
994 if (likely(skb))
995 skb_reserve(skb, 16);
996 return skb;
997}
998#else
999extern struct sk_buff *__dev_alloc_skb(unsigned int length, int gfp_mask);
1000#endif
1001
1002/**
1003 * dev_alloc_skb - allocate an skbuff for sending
1004 * @length: length to allocate
1005 *
1006 * Allocate a new &sk_buff and assign it a usage count of one. The
1007 * buffer has unspecified headroom built in. Users should allocate
1008 * the headroom they think they need without accounting for the
1009 * built in space. The built in space is used for optimisations.
1010 *
1011 * %NULL is returned in there is no free memory. Although this function
1012 * allocates memory it can be called from an interrupt.
1013 */
1014static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1015{
1016 return __dev_alloc_skb(length, GFP_ATOMIC);
1017}
1018
1019/**
1020 * skb_cow - copy header of skb when it is required
1021 * @skb: buffer to cow
1022 * @headroom: needed headroom
1023 *
1024 * If the skb passed lacks sufficient headroom or its data part
1025 * is shared, data is reallocated. If reallocation fails, an error
1026 * is returned and original skb is not changed.
1027 *
1028 * The result is skb with writable area skb->head...skb->tail
1029 * and at least @headroom of space at head.
1030 */
1031static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1032{
1033 int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb);
1034
1035 if (delta < 0)
1036 delta = 0;
1037
1038 if (delta || skb_cloned(skb))
1039 return pskb_expand_head(skb, (delta + 15) & ~15, 0, GFP_ATOMIC);
1040 return 0;
1041}
1042
1043/**
1044 * skb_padto - pad an skbuff up to a minimal size
1045 * @skb: buffer to pad
1046 * @len: minimal length
1047 *
1048 * Pads up a buffer to ensure the trailing bytes exist and are
1049 * blanked. If the buffer already contains sufficient data it
1050 * is untouched. Returns the buffer, which may be a replacement
1051 * for the original, or NULL for out of memory - in which case
1052 * the original buffer is still freed.
1053 */
1054
1055static inline struct sk_buff *skb_padto(struct sk_buff *skb, unsigned int len)
1056{
1057 unsigned int size = skb->len;
1058 if (likely(size >= len))
1059 return skb;
1060 return skb_pad(skb, len-size);
1061}
1062
1063static inline int skb_add_data(struct sk_buff *skb,
1064 char __user *from, int copy)
1065{
1066 const int off = skb->len;
1067
1068 if (skb->ip_summed == CHECKSUM_NONE) {
1069 int err = 0;
1070 unsigned int csum = csum_and_copy_from_user(from,
1071 skb_put(skb, copy),
1072 copy, 0, &err);
1073 if (!err) {
1074 skb->csum = csum_block_add(skb->csum, csum, off);
1075 return 0;
1076 }
1077 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1078 return 0;
1079
1080 __skb_trim(skb, off);
1081 return -EFAULT;
1082}
1083
1084static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1085 struct page *page, int off)
1086{
1087 if (i) {
1088 struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1089
1090 return page == frag->page &&
1091 off == frag->page_offset + frag->size;
1092 }
1093 return 0;
1094}
1095
1096/**
1097 * skb_linearize - convert paged skb to linear one
1098 * @skb: buffer to linarize
1099 * @gfp: allocation mode
1100 *
1101 * If there is no free memory -ENOMEM is returned, otherwise zero
1102 * is returned and the old skb data released.
1103 */
1104extern int __skb_linearize(struct sk_buff *skb, int gfp);
1105static inline int skb_linearize(struct sk_buff *skb, int gfp)
1106{
1107 return __skb_linearize(skb, gfp);
1108}
1109
1110/**
1111 * skb_postpull_rcsum - update checksum for received skb after pull
1112 * @skb: buffer to update
1113 * @start: start of data before pull
1114 * @len: length of data pulled
1115 *
1116 * After doing a pull on a received packet, you need to call this to
1117 * update the CHECKSUM_HW checksum, or set ip_summed to CHECKSUM_NONE
1118 * so that it can be recomputed from scratch.
1119 */
1120
1121static inline void skb_postpull_rcsum(struct sk_buff *skb,
1122 const void *start, int len)
1123{
1124 if (skb->ip_summed == CHECKSUM_HW)
1125 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1126}
1127
1128/**
1129 * pskb_trim_rcsum - trim received skb and update checksum
1130 * @skb: buffer to trim
1131 * @len: new length
1132 *
1133 * This is exactly the same as pskb_trim except that it ensures the
1134 * checksum of received packets are still valid after the operation.
1135 */
1136
1137static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1138{
1139 if (len >= skb->len)
1140 return 0;
1141 if (skb->ip_summed == CHECKSUM_HW)
1142 skb->ip_summed = CHECKSUM_NONE;
1143 return __pskb_trim(skb, len);
1144}
1145
1146static inline void *kmap_skb_frag(const skb_frag_t *frag)
1147{
1148#ifdef CONFIG_HIGHMEM
1149 BUG_ON(in_irq());
1150
1151 local_bh_disable();
1152#endif
1153 return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ);
1154}
1155
1156static inline void kunmap_skb_frag(void *vaddr)
1157{
1158 kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
1159#ifdef CONFIG_HIGHMEM
1160 local_bh_enable();
1161#endif
1162}
1163
1164#define skb_queue_walk(queue, skb) \
1165 for (skb = (queue)->next; \
1166 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1167 skb = skb->next)
1168
1169
1170extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
1171 int noblock, int *err);
1172extern unsigned int datagram_poll(struct file *file, struct socket *sock,
1173 struct poll_table_struct *wait);
1174extern int skb_copy_datagram_iovec(const struct sk_buff *from,
1175 int offset, struct iovec *to,
1176 int size);
1177extern int skb_copy_and_csum_datagram_iovec(const
1178 struct sk_buff *skb,
1179 int hlen,
1180 struct iovec *iov);
1181extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
1182extern unsigned int skb_checksum(const struct sk_buff *skb, int offset,
1183 int len, unsigned int csum);
1184extern int skb_copy_bits(const struct sk_buff *skb, int offset,
1185 void *to, int len);
1186extern unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb,
1187 int offset, u8 *to, int len,
1188 unsigned int csum);
1189extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
1190extern void skb_split(struct sk_buff *skb,
1191 struct sk_buff *skb1, const u32 len);
1192
1193static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
1194 int len, void *buffer)
1195{
1196 int hlen = skb_headlen(skb);
1197
1198 if (offset + len <= hlen)
1199 return skb->data + offset;
1200
1201 if (skb_copy_bits(skb, offset, buffer, len) < 0)
1202 return NULL;
1203
1204 return buffer;
1205}
1206
1207extern void skb_init(void);
1208extern void skb_add_mtu(int mtu);
1209
1210#ifdef CONFIG_NETFILTER
1211static inline void nf_conntrack_put(struct nf_conntrack *nfct)
1212{
1213 if (nfct && atomic_dec_and_test(&nfct->use))
1214 nfct->destroy(nfct);
1215}
1216static inline void nf_conntrack_get(struct nf_conntrack *nfct)
1217{
1218 if (nfct)
1219 atomic_inc(&nfct->use);
1220}
1221static inline void nf_reset(struct sk_buff *skb)
1222{
1223 nf_conntrack_put(skb->nfct);
1224 skb->nfct = NULL;
1225#ifdef CONFIG_NETFILTER_DEBUG
1226 skb->nf_debug = 0;
1227#endif
1228}
1229static inline void nf_reset_debug(struct sk_buff *skb)
1230{
1231#ifdef CONFIG_NETFILTER_DEBUG
1232 skb->nf_debug = 0;
1233#endif
1234}
1235
1236#ifdef CONFIG_BRIDGE_NETFILTER
1237static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
1238{
1239 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
1240 kfree(nf_bridge);
1241}
1242static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
1243{
1244 if (nf_bridge)
1245 atomic_inc(&nf_bridge->use);
1246}
1247#endif /* CONFIG_BRIDGE_NETFILTER */
1248#else /* CONFIG_NETFILTER */
1249static inline void nf_reset(struct sk_buff *skb) {}
1250#endif /* CONFIG_NETFILTER */
1251
1252#endif /* __KERNEL__ */
1253#endif /* _LINUX_SKBUFF_H */
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-03 01:19:37 -0500