direct-io.hg

view linux-2.6-xen-sparse/include/linux/skbuff.h @ 11509:2e6c10dc7c0b

[POWERPC][XEN] make sure put_domain() is called in case of allocate_rma() failuer

Signed-off-by: Jimi Xenidis <jimix@watson.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
author Jimi Xenidis <jimix@watson.ibm.com>
date Tue Sep 12 10:53:46 2006 -0400 (2006-09-12)
parents a4041ac6f152
children aaaa249e6f3b
line source
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 */
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
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>
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 <linux/textsearch.h>
31 #include <net/checksum.h>
33 #define HAVE_ALLOC_SKB /* For the drivers to know */
34 #define HAVE_ALIGNABLE_SKB /* Ditto 8) */
36 #define CHECKSUM_NONE 0
37 #define CHECKSUM_HW 1
38 #define CHECKSUM_UNNECESSARY 2
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))
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 */
86 struct net_device;
88 #ifdef CONFIG_NETFILTER
89 struct nf_conntrack {
90 atomic_t use;
91 void (*destroy)(struct nf_conntrack *);
92 };
94 #ifdef CONFIG_BRIDGE_NETFILTER
95 struct nf_bridge_info {
96 atomic_t use;
97 struct net_device *physindev;
98 struct net_device *physoutdev;
99 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
100 struct net_device *netoutdev;
101 #endif
102 unsigned int mask;
103 unsigned long data[32 / sizeof(unsigned long)];
104 };
105 #endif
107 #endif
109 struct sk_buff_head {
110 /* These two members must be first. */
111 struct sk_buff *next;
112 struct sk_buff *prev;
114 __u32 qlen;
115 spinlock_t lock;
116 };
118 struct sk_buff;
120 /* To allow 64K frame to be packed as single skb without frag_list */
121 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
123 typedef struct skb_frag_struct skb_frag_t;
125 struct skb_frag_struct {
126 struct page *page;
127 __u16 page_offset;
128 __u16 size;
129 };
131 /* This data is invariant across clones and lives at
132 * the end of the header data, ie. at skb->end.
133 */
134 struct skb_shared_info {
135 atomic_t dataref;
136 unsigned short nr_frags;
137 unsigned short gso_size;
138 /* Warning: this field is not always filled in (UFO)! */
139 unsigned short gso_segs;
140 unsigned short gso_type;
141 unsigned int ip6_frag_id;
142 struct sk_buff *frag_list;
143 skb_frag_t frags[MAX_SKB_FRAGS];
144 };
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)
160 struct skb_timeval {
161 u32 off_sec;
162 u32 off_usec;
163 };
166 enum {
167 SKB_FCLONE_UNAVAILABLE,
168 SKB_FCLONE_ORIG,
169 SKB_FCLONE_CLONE,
170 };
172 enum {
173 SKB_GSO_TCPV4 = 1 << 0,
174 SKB_GSO_UDPV4 = 1 << 1,
176 /* This indicates the skb is from an untrusted source. */
177 SKB_GSO_DODGY = 1 << 2,
178 };
180 /**
181 * struct sk_buff - socket buffer
182 * @next: Next buffer in list
183 * @prev: Previous buffer in list
184 * @sk: Socket we are owned by
185 * @tstamp: Time we arrived
186 * @dev: Device we arrived on/are leaving by
187 * @input_dev: Device we arrived on
188 * @h: Transport layer header
189 * @nh: Network layer header
190 * @mac: Link layer header
191 * @dst: destination entry
192 * @sp: the security path, used for xfrm
193 * @cb: Control buffer. Free for use by every layer. Put private vars here
194 * @len: Length of actual data
195 * @data_len: Data length
196 * @mac_len: Length of link layer header
197 * @csum: Checksum
198 * @local_df: allow local fragmentation
199 * @cloned: Head may be cloned (check refcnt to be sure)
200 * @nohdr: Payload reference only, must not modify header
201 * @proto_data_valid: Protocol data validated since arriving at localhost
202 * @proto_csum_blank: Protocol csum must be added before leaving localhost
203 * @pkt_type: Packet class
204 * @fclone: skbuff clone status
205 * @ip_summed: Driver fed us an IP checksum
206 * @priority: Packet queueing priority
207 * @users: User count - see {datagram,tcp}.c
208 * @protocol: Packet protocol from driver
209 * @truesize: Buffer size
210 * @head: Head of buffer
211 * @data: Data head pointer
212 * @tail: Tail pointer
213 * @end: End pointer
214 * @destructor: Destruct function
215 * @nfmark: Can be used for communication between hooks
216 * @nfct: Associated connection, if any
217 * @ipvs_property: skbuff is owned by ipvs
218 * @nfctinfo: Relationship of this skb to the connection
219 * @nfct_reasm: netfilter conntrack re-assembly pointer
220 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
221 * @tc_index: Traffic control index
222 * @tc_verd: traffic control verdict
223 */
225 struct sk_buff {
226 /* These two members must be first. */
227 struct sk_buff *next;
228 struct sk_buff *prev;
230 struct sock *sk;
231 struct skb_timeval tstamp;
232 struct net_device *dev;
233 struct net_device *input_dev;
235 union {
236 struct tcphdr *th;
237 struct udphdr *uh;
238 struct icmphdr *icmph;
239 struct igmphdr *igmph;
240 struct iphdr *ipiph;
241 struct ipv6hdr *ipv6h;
242 unsigned char *raw;
243 } h;
245 union {
246 struct iphdr *iph;
247 struct ipv6hdr *ipv6h;
248 struct arphdr *arph;
249 unsigned char *raw;
250 } nh;
252 union {
253 unsigned char *raw;
254 } mac;
256 struct dst_entry *dst;
257 struct sec_path *sp;
259 /*
260 * This is the control buffer. It is free to use for every
261 * layer. Please put your private variables there. If you
262 * want to keep them across layers you have to do a skb_clone()
263 * first. This is owned by whoever has the skb queued ATM.
264 */
265 char cb[48];
267 unsigned int len,
268 data_len,
269 mac_len,
270 csum;
271 __u32 priority;
272 __u8 local_df:1,
273 cloned:1,
274 ip_summed:2,
275 nohdr:1,
276 nfctinfo:3;
277 __u8 pkt_type:3,
278 fclone:2,
279 #ifndef CONFIG_XEN
280 ipvs_property:1;
281 #else
282 ipvs_property:1,
283 proto_data_valid:1,
284 proto_csum_blank:1;
285 #endif
286 __be16 protocol;
288 void (*destructor)(struct sk_buff *skb);
289 #ifdef CONFIG_NETFILTER
290 __u32 nfmark;
291 struct nf_conntrack *nfct;
292 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
293 struct sk_buff *nfct_reasm;
294 #endif
295 #ifdef CONFIG_BRIDGE_NETFILTER
296 struct nf_bridge_info *nf_bridge;
297 #endif
298 #endif /* CONFIG_NETFILTER */
299 #ifdef CONFIG_NET_SCHED
300 __u16 tc_index; /* traffic control index */
301 #ifdef CONFIG_NET_CLS_ACT
302 __u16 tc_verd; /* traffic control verdict */
303 #endif
304 #endif
307 /* These elements must be at the end, see alloc_skb() for details. */
308 unsigned int truesize;
309 atomic_t users;
310 unsigned char *head,
311 *data,
312 *tail,
313 *end;
314 };
316 #ifdef __KERNEL__
317 /*
318 * Handling routines are only of interest to the kernel
319 */
320 #include <linux/slab.h>
322 #include <asm/system.h>
324 extern void __kfree_skb(struct sk_buff *skb);
325 extern struct sk_buff *__alloc_skb(unsigned int size,
326 gfp_t priority, int fclone);
327 static inline struct sk_buff *alloc_skb(unsigned int size,
328 gfp_t priority)
329 {
330 return __alloc_skb(size, priority, 0);
331 }
333 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
334 gfp_t priority)
335 {
336 return __alloc_skb(size, priority, 1);
337 }
339 extern struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
340 unsigned int size,
341 gfp_t priority,
342 int fclone);
343 extern void kfree_skbmem(struct sk_buff *skb);
344 extern struct sk_buff *skb_clone(struct sk_buff *skb,
345 gfp_t priority);
346 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
347 gfp_t priority);
348 extern struct sk_buff *pskb_copy(struct sk_buff *skb,
349 gfp_t gfp_mask);
350 extern int pskb_expand_head(struct sk_buff *skb,
351 int nhead, int ntail,
352 gfp_t gfp_mask);
353 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
354 unsigned int headroom);
355 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
356 int newheadroom, int newtailroom,
357 gfp_t priority);
358 extern struct sk_buff * skb_pad(struct sk_buff *skb, int pad);
359 #define dev_kfree_skb(a) kfree_skb(a)
360 extern void skb_over_panic(struct sk_buff *skb, int len,
361 void *here);
362 extern void skb_under_panic(struct sk_buff *skb, int len,
363 void *here);
365 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
366 int getfrag(void *from, char *to, int offset,
367 int len,int odd, struct sk_buff *skb),
368 void *from, int length);
370 struct skb_seq_state
371 {
372 __u32 lower_offset;
373 __u32 upper_offset;
374 __u32 frag_idx;
375 __u32 stepped_offset;
376 struct sk_buff *root_skb;
377 struct sk_buff *cur_skb;
378 __u8 *frag_data;
379 };
381 extern void skb_prepare_seq_read(struct sk_buff *skb,
382 unsigned int from, unsigned int to,
383 struct skb_seq_state *st);
384 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
385 struct skb_seq_state *st);
386 extern void skb_abort_seq_read(struct skb_seq_state *st);
388 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
389 unsigned int to, struct ts_config *config,
390 struct ts_state *state);
392 /* Internal */
393 #define skb_shinfo(SKB) ((struct skb_shared_info *)((SKB)->end))
395 /**
396 * skb_queue_empty - check if a queue is empty
397 * @list: queue head
398 *
399 * Returns true if the queue is empty, false otherwise.
400 */
401 static inline int skb_queue_empty(const struct sk_buff_head *list)
402 {
403 return list->next == (struct sk_buff *)list;
404 }
406 /**
407 * skb_get - reference buffer
408 * @skb: buffer to reference
409 *
410 * Makes another reference to a socket buffer and returns a pointer
411 * to the buffer.
412 */
413 static inline struct sk_buff *skb_get(struct sk_buff *skb)
414 {
415 atomic_inc(&skb->users);
416 return skb;
417 }
419 /*
420 * If users == 1, we are the only owner and are can avoid redundant
421 * atomic change.
422 */
424 /**
425 * kfree_skb - free an sk_buff
426 * @skb: buffer to free
427 *
428 * Drop a reference to the buffer and free it if the usage count has
429 * hit zero.
430 */
431 static inline void kfree_skb(struct sk_buff *skb)
432 {
433 if (likely(atomic_read(&skb->users) == 1))
434 smp_rmb();
435 else if (likely(!atomic_dec_and_test(&skb->users)))
436 return;
437 __kfree_skb(skb);
438 }
440 /**
441 * skb_cloned - is the buffer a clone
442 * @skb: buffer to check
443 *
444 * Returns true if the buffer was generated with skb_clone() and is
445 * one of multiple shared copies of the buffer. Cloned buffers are
446 * shared data so must not be written to under normal circumstances.
447 */
448 static inline int skb_cloned(const struct sk_buff *skb)
449 {
450 return skb->cloned &&
451 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
452 }
454 /**
455 * skb_header_cloned - is the header a clone
456 * @skb: buffer to check
457 *
458 * Returns true if modifying the header part of the buffer requires
459 * the data to be copied.
460 */
461 static inline int skb_header_cloned(const struct sk_buff *skb)
462 {
463 int dataref;
465 if (!skb->cloned)
466 return 0;
468 dataref = atomic_read(&skb_shinfo(skb)->dataref);
469 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
470 return dataref != 1;
471 }
473 /**
474 * skb_header_release - release reference to header
475 * @skb: buffer to operate on
476 *
477 * Drop a reference to the header part of the buffer. This is done
478 * by acquiring a payload reference. You must not read from the header
479 * part of skb->data after this.
480 */
481 static inline void skb_header_release(struct sk_buff *skb)
482 {
483 BUG_ON(skb->nohdr);
484 skb->nohdr = 1;
485 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
486 }
488 /**
489 * skb_shared - is the buffer shared
490 * @skb: buffer to check
491 *
492 * Returns true if more than one person has a reference to this
493 * buffer.
494 */
495 static inline int skb_shared(const struct sk_buff *skb)
496 {
497 return atomic_read(&skb->users) != 1;
498 }
500 /**
501 * skb_share_check - check if buffer is shared and if so clone it
502 * @skb: buffer to check
503 * @pri: priority for memory allocation
504 *
505 * If the buffer is shared the buffer is cloned and the old copy
506 * drops a reference. A new clone with a single reference is returned.
507 * If the buffer is not shared the original buffer is returned. When
508 * being called from interrupt status or with spinlocks held pri must
509 * be GFP_ATOMIC.
510 *
511 * NULL is returned on a memory allocation failure.
512 */
513 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
514 gfp_t pri)
515 {
516 might_sleep_if(pri & __GFP_WAIT);
517 if (skb_shared(skb)) {
518 struct sk_buff *nskb = skb_clone(skb, pri);
519 kfree_skb(skb);
520 skb = nskb;
521 }
522 return skb;
523 }
525 /*
526 * Copy shared buffers into a new sk_buff. We effectively do COW on
527 * packets to handle cases where we have a local reader and forward
528 * and a couple of other messy ones. The normal one is tcpdumping
529 * a packet thats being forwarded.
530 */
532 /**
533 * skb_unshare - make a copy of a shared buffer
534 * @skb: buffer to check
535 * @pri: priority for memory allocation
536 *
537 * If the socket buffer is a clone then this function creates a new
538 * copy of the data, drops a reference count on the old copy and returns
539 * the new copy with the reference count at 1. If the buffer is not a clone
540 * the original buffer is returned. When called with a spinlock held or
541 * from interrupt state @pri must be %GFP_ATOMIC
542 *
543 * %NULL is returned on a memory allocation failure.
544 */
545 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
546 gfp_t pri)
547 {
548 might_sleep_if(pri & __GFP_WAIT);
549 if (skb_cloned(skb)) {
550 struct sk_buff *nskb = skb_copy(skb, pri);
551 kfree_skb(skb); /* Free our shared copy */
552 skb = nskb;
553 }
554 return skb;
555 }
557 /**
558 * skb_peek
559 * @list_: list to peek at
560 *
561 * Peek an &sk_buff. Unlike most other operations you _MUST_
562 * be careful with this one. A peek leaves the buffer on the
563 * list and someone else may run off with it. You must hold
564 * the appropriate locks or have a private queue to do this.
565 *
566 * Returns %NULL for an empty list or a pointer to the head element.
567 * The reference count is not incremented and the reference is therefore
568 * volatile. Use with caution.
569 */
570 static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
571 {
572 struct sk_buff *list = ((struct sk_buff *)list_)->next;
573 if (list == (struct sk_buff *)list_)
574 list = NULL;
575 return list;
576 }
578 /**
579 * skb_peek_tail
580 * @list_: list to peek at
581 *
582 * Peek an &sk_buff. Unlike most other operations you _MUST_
583 * be careful with this one. A peek leaves the buffer on the
584 * list and someone else may run off with it. You must hold
585 * the appropriate locks or have a private queue to do this.
586 *
587 * Returns %NULL for an empty list or a pointer to the tail element.
588 * The reference count is not incremented and the reference is therefore
589 * volatile. Use with caution.
590 */
591 static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
592 {
593 struct sk_buff *list = ((struct sk_buff *)list_)->prev;
594 if (list == (struct sk_buff *)list_)
595 list = NULL;
596 return list;
597 }
599 /**
600 * skb_queue_len - get queue length
601 * @list_: list to measure
602 *
603 * Return the length of an &sk_buff queue.
604 */
605 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
606 {
607 return list_->qlen;
608 }
610 static inline void skb_queue_head_init(struct sk_buff_head *list)
611 {
612 spin_lock_init(&list->lock);
613 list->prev = list->next = (struct sk_buff *)list;
614 list->qlen = 0;
615 }
617 /*
618 * Insert an sk_buff at the start of a list.
619 *
620 * The "__skb_xxxx()" functions are the non-atomic ones that
621 * can only be called with interrupts disabled.
622 */
624 /**
625 * __skb_queue_after - queue a buffer at the list head
626 * @list: list to use
627 * @prev: place after this buffer
628 * @newsk: buffer to queue
629 *
630 * Queue a buffer int the middle of a list. This function takes no locks
631 * and you must therefore hold required locks before calling it.
632 *
633 * A buffer cannot be placed on two lists at the same time.
634 */
635 static inline void __skb_queue_after(struct sk_buff_head *list,
636 struct sk_buff *prev,
637 struct sk_buff *newsk)
638 {
639 struct sk_buff *next;
640 list->qlen++;
642 next = prev->next;
643 newsk->next = next;
644 newsk->prev = prev;
645 next->prev = prev->next = newsk;
646 }
648 /**
649 * __skb_queue_head - queue a buffer at the list head
650 * @list: list to use
651 * @newsk: buffer to queue
652 *
653 * Queue a buffer at the start of a list. This function takes no locks
654 * and you must therefore hold required locks before calling it.
655 *
656 * A buffer cannot be placed on two lists at the same time.
657 */
658 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
659 static inline void __skb_queue_head(struct sk_buff_head *list,
660 struct sk_buff *newsk)
661 {
662 __skb_queue_after(list, (struct sk_buff *)list, newsk);
663 }
665 /**
666 * __skb_queue_tail - queue a buffer at the list tail
667 * @list: list to use
668 * @newsk: buffer to queue
669 *
670 * Queue a buffer at the end of a list. This function takes no locks
671 * and you must therefore hold required locks before calling it.
672 *
673 * A buffer cannot be placed on two lists at the same time.
674 */
675 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
676 static inline void __skb_queue_tail(struct sk_buff_head *list,
677 struct sk_buff *newsk)
678 {
679 struct sk_buff *prev, *next;
681 list->qlen++;
682 next = (struct sk_buff *)list;
683 prev = next->prev;
684 newsk->next = next;
685 newsk->prev = prev;
686 next->prev = prev->next = newsk;
687 }
690 /**
691 * __skb_dequeue - remove from the head of the queue
692 * @list: list to dequeue from
693 *
694 * Remove the head of the list. This function does not take any locks
695 * so must be used with appropriate locks held only. The head item is
696 * returned or %NULL if the list is empty.
697 */
698 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
699 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
700 {
701 struct sk_buff *next, *prev, *result;
703 prev = (struct sk_buff *) list;
704 next = prev->next;
705 result = NULL;
706 if (next != prev) {
707 result = next;
708 next = next->next;
709 list->qlen--;
710 next->prev = prev;
711 prev->next = next;
712 result->next = result->prev = NULL;
713 }
714 return result;
715 }
718 /*
719 * Insert a packet on a list.
720 */
721 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
722 static inline void __skb_insert(struct sk_buff *newsk,
723 struct sk_buff *prev, struct sk_buff *next,
724 struct sk_buff_head *list)
725 {
726 newsk->next = next;
727 newsk->prev = prev;
728 next->prev = prev->next = newsk;
729 list->qlen++;
730 }
732 /*
733 * Place a packet after a given packet in a list.
734 */
735 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
736 static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
737 {
738 __skb_insert(newsk, old, old->next, list);
739 }
741 /*
742 * remove sk_buff from list. _Must_ be called atomically, and with
743 * the list known..
744 */
745 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
746 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
747 {
748 struct sk_buff *next, *prev;
750 list->qlen--;
751 next = skb->next;
752 prev = skb->prev;
753 skb->next = skb->prev = NULL;
754 next->prev = prev;
755 prev->next = next;
756 }
759 /* XXX: more streamlined implementation */
761 /**
762 * __skb_dequeue_tail - remove from the tail of the queue
763 * @list: list to dequeue from
764 *
765 * Remove the tail of the list. This function does not take any locks
766 * so must be used with appropriate locks held only. The tail item is
767 * returned or %NULL if the list is empty.
768 */
769 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
770 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
771 {
772 struct sk_buff *skb = skb_peek_tail(list);
773 if (skb)
774 __skb_unlink(skb, list);
775 return skb;
776 }
779 static inline int skb_is_nonlinear(const struct sk_buff *skb)
780 {
781 return skb->data_len;
782 }
784 static inline unsigned int skb_headlen(const struct sk_buff *skb)
785 {
786 return skb->len - skb->data_len;
787 }
789 static inline int skb_pagelen(const struct sk_buff *skb)
790 {
791 int i, len = 0;
793 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
794 len += skb_shinfo(skb)->frags[i].size;
795 return len + skb_headlen(skb);
796 }
798 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
799 struct page *page, int off, int size)
800 {
801 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
803 frag->page = page;
804 frag->page_offset = off;
805 frag->size = size;
806 skb_shinfo(skb)->nr_frags = i + 1;
807 }
809 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
810 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list)
811 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
813 /*
814 * Add data to an sk_buff
815 */
816 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
817 {
818 unsigned char *tmp = skb->tail;
819 SKB_LINEAR_ASSERT(skb);
820 skb->tail += len;
821 skb->len += len;
822 return tmp;
823 }
825 /**
826 * skb_put - add data to a buffer
827 * @skb: buffer to use
828 * @len: amount of data to add
829 *
830 * This function extends the used data area of the buffer. If this would
831 * exceed the total buffer size the kernel will panic. A pointer to the
832 * first byte of the extra data is returned.
833 */
834 static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
835 {
836 unsigned char *tmp = skb->tail;
837 SKB_LINEAR_ASSERT(skb);
838 skb->tail += len;
839 skb->len += len;
840 if (unlikely(skb->tail>skb->end))
841 skb_over_panic(skb, len, current_text_addr());
842 return tmp;
843 }
845 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
846 {
847 skb->data -= len;
848 skb->len += len;
849 return skb->data;
850 }
852 /**
853 * skb_push - add data to the start of a buffer
854 * @skb: buffer to use
855 * @len: amount of data to add
856 *
857 * This function extends the used data area of the buffer at the buffer
858 * start. If this would exceed the total buffer headroom the kernel will
859 * panic. A pointer to the first byte of the extra data is returned.
860 */
861 static inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
862 {
863 skb->data -= len;
864 skb->len += len;
865 if (unlikely(skb->data<skb->head))
866 skb_under_panic(skb, len, current_text_addr());
867 return skb->data;
868 }
870 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
871 {
872 skb->len -= len;
873 BUG_ON(skb->len < skb->data_len);
874 return skb->data += len;
875 }
877 /**
878 * skb_pull - remove data from the start of a buffer
879 * @skb: buffer to use
880 * @len: amount of data to remove
881 *
882 * This function removes data from the start of a buffer, returning
883 * the memory to the headroom. A pointer to the next data in the buffer
884 * is returned. Once the data has been pulled future pushes will overwrite
885 * the old data.
886 */
887 static inline unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
888 {
889 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
890 }
892 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
894 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
895 {
896 if (len > skb_headlen(skb) &&
897 !__pskb_pull_tail(skb, len-skb_headlen(skb)))
898 return NULL;
899 skb->len -= len;
900 return skb->data += len;
901 }
903 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
904 {
905 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
906 }
908 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
909 {
910 if (likely(len <= skb_headlen(skb)))
911 return 1;
912 if (unlikely(len > skb->len))
913 return 0;
914 return __pskb_pull_tail(skb, len-skb_headlen(skb)) != NULL;
915 }
917 /**
918 * skb_headroom - bytes at buffer head
919 * @skb: buffer to check
920 *
921 * Return the number of bytes of free space at the head of an &sk_buff.
922 */
923 static inline int skb_headroom(const struct sk_buff *skb)
924 {
925 return skb->data - skb->head;
926 }
928 /**
929 * skb_tailroom - bytes at buffer end
930 * @skb: buffer to check
931 *
932 * Return the number of bytes of free space at the tail of an sk_buff
933 */
934 static inline int skb_tailroom(const struct sk_buff *skb)
935 {
936 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
937 }
939 /**
940 * skb_reserve - adjust headroom
941 * @skb: buffer to alter
942 * @len: bytes to move
943 *
944 * Increase the headroom of an empty &sk_buff by reducing the tail
945 * room. This is only allowed for an empty buffer.
946 */
947 static inline void skb_reserve(struct sk_buff *skb, int len)
948 {
949 skb->data += len;
950 skb->tail += len;
951 }
953 /*
954 * CPUs often take a performance hit when accessing unaligned memory
955 * locations. The actual performance hit varies, it can be small if the
956 * hardware handles it or large if we have to take an exception and fix it
957 * in software.
958 *
959 * Since an ethernet header is 14 bytes network drivers often end up with
960 * the IP header at an unaligned offset. The IP header can be aligned by
961 * shifting the start of the packet by 2 bytes. Drivers should do this
962 * with:
963 *
964 * skb_reserve(NET_IP_ALIGN);
965 *
966 * The downside to this alignment of the IP header is that the DMA is now
967 * unaligned. On some architectures the cost of an unaligned DMA is high
968 * and this cost outweighs the gains made by aligning the IP header.
969 *
970 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
971 * to be overridden.
972 */
973 #ifndef NET_IP_ALIGN
974 #define NET_IP_ALIGN 2
975 #endif
977 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
979 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
980 {
981 if (!skb->data_len) {
982 skb->len = len;
983 skb->tail = skb->data + len;
984 } else
985 ___pskb_trim(skb, len, 0);
986 }
988 /**
989 * skb_trim - remove end from a buffer
990 * @skb: buffer to alter
991 * @len: new length
992 *
993 * Cut the length of a buffer down by removing data from the tail. If
994 * the buffer is already under the length specified it is not modified.
995 */
996 static inline void skb_trim(struct sk_buff *skb, unsigned int len)
997 {
998 if (skb->len > len)
999 __skb_trim(skb, len);
1003 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1005 if (!skb->data_len) {
1006 skb->len = len;
1007 skb->tail = skb->data+len;
1008 return 0;
1010 return ___pskb_trim(skb, len, 1);
1013 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1015 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1018 /**
1019 * skb_orphan - orphan a buffer
1020 * @skb: buffer to orphan
1022 * If a buffer currently has an owner then we call the owner's
1023 * destructor function and make the @skb unowned. The buffer continues
1024 * to exist but is no longer charged to its former owner.
1025 */
1026 static inline void skb_orphan(struct sk_buff *skb)
1028 if (skb->destructor)
1029 skb->destructor(skb);
1030 skb->destructor = NULL;
1031 skb->sk = NULL;
1034 /**
1035 * __skb_queue_purge - empty a list
1036 * @list: list to empty
1038 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1039 * the list and one reference dropped. This function does not take the
1040 * list lock and the caller must hold the relevant locks to use it.
1041 */
1042 extern void skb_queue_purge(struct sk_buff_head *list);
1043 static inline void __skb_queue_purge(struct sk_buff_head *list)
1045 struct sk_buff *skb;
1046 while ((skb = __skb_dequeue(list)) != NULL)
1047 kfree_skb(skb);
1050 #ifndef CONFIG_HAVE_ARCH_DEV_ALLOC_SKB
1051 /**
1052 * __dev_alloc_skb - allocate an skbuff for sending
1053 * @length: length to allocate
1054 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1056 * Allocate a new &sk_buff and assign it a usage count of one. The
1057 * buffer has unspecified headroom built in. Users should allocate
1058 * the headroom they think they need without accounting for the
1059 * built in space. The built in space is used for optimisations.
1061 * %NULL is returned in there is no free memory.
1062 */
1063 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1064 gfp_t gfp_mask)
1066 struct sk_buff *skb = alloc_skb(length + 16, gfp_mask);
1067 if (likely(skb))
1068 skb_reserve(skb, 16);
1069 return skb;
1071 #else
1072 extern struct sk_buff *__dev_alloc_skb(unsigned int length, gfp_t gfp_mask);
1073 #endif
1075 /**
1076 * dev_alloc_skb - allocate an skbuff for sending
1077 * @length: length to allocate
1079 * Allocate a new &sk_buff and assign it a usage count of one. The
1080 * buffer has unspecified headroom built in. Users should allocate
1081 * the headroom they think they need without accounting for the
1082 * built in space. The built in space is used for optimisations.
1084 * %NULL is returned in there is no free memory. Although this function
1085 * allocates memory it can be called from an interrupt.
1086 */
1087 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1089 return __dev_alloc_skb(length, GFP_ATOMIC);
1092 /**
1093 * skb_cow - copy header of skb when it is required
1094 * @skb: buffer to cow
1095 * @headroom: needed headroom
1097 * If the skb passed lacks sufficient headroom or its data part
1098 * is shared, data is reallocated. If reallocation fails, an error
1099 * is returned and original skb is not changed.
1101 * The result is skb with writable area skb->head...skb->tail
1102 * and at least @headroom of space at head.
1103 */
1104 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1106 int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb);
1108 if (delta < 0)
1109 delta = 0;
1111 if (delta || skb_cloned(skb))
1112 return pskb_expand_head(skb, (delta + 15) & ~15, 0, GFP_ATOMIC);
1113 return 0;
1116 /**
1117 * skb_padto - pad an skbuff up to a minimal size
1118 * @skb: buffer to pad
1119 * @len: minimal length
1121 * Pads up a buffer to ensure the trailing bytes exist and are
1122 * blanked. If the buffer already contains sufficient data it
1123 * is untouched. Returns the buffer, which may be a replacement
1124 * for the original, or NULL for out of memory - in which case
1125 * the original buffer is still freed.
1126 */
1128 static inline struct sk_buff *skb_padto(struct sk_buff *skb, unsigned int len)
1130 unsigned int size = skb->len;
1131 if (likely(size >= len))
1132 return skb;
1133 return skb_pad(skb, len-size);
1136 static inline int skb_add_data(struct sk_buff *skb,
1137 char __user *from, int copy)
1139 const int off = skb->len;
1141 if (skb->ip_summed == CHECKSUM_NONE) {
1142 int err = 0;
1143 unsigned int csum = csum_and_copy_from_user(from,
1144 skb_put(skb, copy),
1145 copy, 0, &err);
1146 if (!err) {
1147 skb->csum = csum_block_add(skb->csum, csum, off);
1148 return 0;
1150 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1151 return 0;
1153 __skb_trim(skb, off);
1154 return -EFAULT;
1157 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1158 struct page *page, int off)
1160 if (i) {
1161 struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1163 return page == frag->page &&
1164 off == frag->page_offset + frag->size;
1166 return 0;
1169 static inline int __skb_linearize(struct sk_buff *skb)
1171 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1174 /**
1175 * skb_linearize - convert paged skb to linear one
1176 * @skb: buffer to linarize
1178 * If there is no free memory -ENOMEM is returned, otherwise zero
1179 * is returned and the old skb data released.
1180 */
1181 static inline int skb_linearize(struct sk_buff *skb)
1183 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1186 /**
1187 * skb_linearize_cow - make sure skb is linear and writable
1188 * @skb: buffer to process
1190 * If there is no free memory -ENOMEM is returned, otherwise zero
1191 * is returned and the old skb data released.
1192 */
1193 static inline int skb_linearize_cow(struct sk_buff *skb)
1195 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1196 __skb_linearize(skb) : 0;
1199 /**
1200 * skb_postpull_rcsum - update checksum for received skb after pull
1201 * @skb: buffer to update
1202 * @start: start of data before pull
1203 * @len: length of data pulled
1205 * After doing a pull on a received packet, you need to call this to
1206 * update the CHECKSUM_HW checksum, or set ip_summed to CHECKSUM_NONE
1207 * so that it can be recomputed from scratch.
1208 */
1210 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1211 const void *start, int len)
1213 if (skb->ip_summed == CHECKSUM_HW)
1214 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1217 /**
1218 * pskb_trim_rcsum - trim received skb and update checksum
1219 * @skb: buffer to trim
1220 * @len: new length
1222 * This is exactly the same as pskb_trim except that it ensures the
1223 * checksum of received packets are still valid after the operation.
1224 */
1226 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1228 if (likely(len >= skb->len))
1229 return 0;
1230 if (skb->ip_summed == CHECKSUM_HW)
1231 skb->ip_summed = CHECKSUM_NONE;
1232 return __pskb_trim(skb, len);
1235 static inline void *kmap_skb_frag(const skb_frag_t *frag)
1237 #ifdef CONFIG_HIGHMEM
1238 BUG_ON(in_irq());
1240 local_bh_disable();
1241 #endif
1242 return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ);
1245 static inline void kunmap_skb_frag(void *vaddr)
1247 kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
1248 #ifdef CONFIG_HIGHMEM
1249 local_bh_enable();
1250 #endif
1253 #define skb_queue_walk(queue, skb) \
1254 for (skb = (queue)->next; \
1255 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1256 skb = skb->next)
1258 #define skb_queue_reverse_walk(queue, skb) \
1259 for (skb = (queue)->prev; \
1260 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1261 skb = skb->prev)
1264 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
1265 int noblock, int *err);
1266 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
1267 struct poll_table_struct *wait);
1268 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
1269 int offset, struct iovec *to,
1270 int size);
1271 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
1272 int hlen,
1273 struct iovec *iov);
1274 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
1275 extern void skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
1276 unsigned int flags);
1277 extern unsigned int skb_checksum(const struct sk_buff *skb, int offset,
1278 int len, unsigned int csum);
1279 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
1280 void *to, int len);
1281 extern int skb_store_bits(const struct sk_buff *skb, int offset,
1282 void *from, int len);
1283 extern unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb,
1284 int offset, u8 *to, int len,
1285 unsigned int csum);
1286 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
1287 extern void skb_split(struct sk_buff *skb,
1288 struct sk_buff *skb1, const u32 len);
1290 extern void skb_release_data(struct sk_buff *skb);
1291 extern struct sk_buff *skb_segment(struct sk_buff *skb, int features);
1293 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
1294 int len, void *buffer)
1296 int hlen = skb_headlen(skb);
1298 if (hlen - offset >= len)
1299 return skb->data + offset;
1301 if (skb_copy_bits(skb, offset, buffer, len) < 0)
1302 return NULL;
1304 return buffer;
1307 extern void skb_init(void);
1308 extern void skb_add_mtu(int mtu);
1310 /**
1311 * skb_get_timestamp - get timestamp from a skb
1312 * @skb: skb to get stamp from
1313 * @stamp: pointer to struct timeval to store stamp in
1315 * Timestamps are stored in the skb as offsets to a base timestamp.
1316 * This function converts the offset back to a struct timeval and stores
1317 * it in stamp.
1318 */
1319 static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *stamp)
1321 stamp->tv_sec = skb->tstamp.off_sec;
1322 stamp->tv_usec = skb->tstamp.off_usec;
1325 /**
1326 * skb_set_timestamp - set timestamp of a skb
1327 * @skb: skb to set stamp of
1328 * @stamp: pointer to struct timeval to get stamp from
1330 * Timestamps are stored in the skb as offsets to a base timestamp.
1331 * This function converts a struct timeval to an offset and stores
1332 * it in the skb.
1333 */
1334 static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp)
1336 skb->tstamp.off_sec = stamp->tv_sec;
1337 skb->tstamp.off_usec = stamp->tv_usec;
1340 extern void __net_timestamp(struct sk_buff *skb);
1342 extern unsigned int __skb_checksum_complete(struct sk_buff *skb);
1344 /**
1345 * skb_checksum_complete - Calculate checksum of an entire packet
1346 * @skb: packet to process
1348 * This function calculates the checksum over the entire packet plus
1349 * the value of skb->csum. The latter can be used to supply the
1350 * checksum of a pseudo header as used by TCP/UDP. It returns the
1351 * checksum.
1353 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
1354 * this function can be used to verify that checksum on received
1355 * packets. In that case the function should return zero if the
1356 * checksum is correct. In particular, this function will return zero
1357 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
1358 * hardware has already verified the correctness of the checksum.
1359 */
1360 static inline unsigned int skb_checksum_complete(struct sk_buff *skb)
1362 return skb->ip_summed != CHECKSUM_UNNECESSARY &&
1363 __skb_checksum_complete(skb);
1366 #ifdef CONFIG_NETFILTER
1367 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
1369 if (nfct && atomic_dec_and_test(&nfct->use))
1370 nfct->destroy(nfct);
1372 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
1374 if (nfct)
1375 atomic_inc(&nfct->use);
1377 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1378 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
1380 if (skb)
1381 atomic_inc(&skb->users);
1383 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
1385 if (skb)
1386 kfree_skb(skb);
1388 #endif
1389 static inline void nf_reset(struct sk_buff *skb)
1391 nf_conntrack_put(skb->nfct);
1392 skb->nfct = NULL;
1393 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1394 nf_conntrack_put_reasm(skb->nfct_reasm);
1395 skb->nfct_reasm = NULL;
1396 #endif
1399 #ifdef CONFIG_BRIDGE_NETFILTER
1400 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
1402 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
1403 kfree(nf_bridge);
1405 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
1407 if (nf_bridge)
1408 atomic_inc(&nf_bridge->use);
1410 #endif /* CONFIG_BRIDGE_NETFILTER */
1411 #else /* CONFIG_NETFILTER */
1412 static inline void nf_reset(struct sk_buff *skb) {}
1413 #endif /* CONFIG_NETFILTER */
1415 static inline int skb_is_gso(const struct sk_buff *skb)
1417 return skb_shinfo(skb)->gso_size;
1420 #endif /* __KERNEL__ */
1421 #endif /* _LINUX_SKBUFF_H */