2 * Definitions for the 'struct sk_buff' memory handlers.
5 * Alan Cox, <gw4pts@gw4pts.ampr.org>
6 * Florian La Roche, <rzsfl@rz.uni-sb.de>
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.
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
17 #include <linux/kernel.h>
18 #include <linux/compiler.h>
19 #include <linux/time.h>
20 #include <linux/cache.h>
22 #include <asm/atomic.h>
23 #include <asm/types.h>
24 #include <linux/spinlock.h>
25 #include <linux/net.h>
26 #include <linux/textsearch.h>
27 #include <net/checksum.h>
28 #include <linux/rcupdate.h>
29 #include <linux/dmaengine.h>
30 #include <linux/hrtimer.h>
32 #define HAVE_ALLOC_SKB /* For the drivers to know */
33 #define HAVE_ALIGNABLE_SKB /* Ditto 8) */
35 #define CHECKSUM_NONE 0
36 #define CHECKSUM_PARTIAL 1
37 #define CHECKSUM_UNNECESSARY 2
38 #define CHECKSUM_COMPLETE 3
40 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
41 ~(SMP_CACHE_BYTES - 1))
42 #define SKB_WITH_OVERHEAD(X) \
43 (((X) - sizeof(struct skb_shared_info)) & \
44 ~(SMP_CACHE_BYTES - 1))
45 #define SKB_MAX_ORDER(X, ORDER) \
46 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
47 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
48 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
50 /* A. Checksumming of received packets by device.
52 * NONE: device failed to checksum this packet.
53 * skb->csum is undefined.
55 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
56 * skb->csum is undefined.
57 * It is bad option, but, unfortunately, many of vendors do this.
58 * Apparently with secret goal to sell you new device, when you
59 * will add new protocol to your host. F.e. IPv6. 8)
61 * COMPLETE: the most generic way. Device supplied checksum of _all_
62 * the packet as seen by netif_rx in skb->csum.
63 * NOTE: Even if device supports only some protocols, but
64 * is able to produce some skb->csum, it MUST use COMPLETE,
67 * B. Checksumming on output.
69 * NONE: skb is checksummed by protocol or csum is not required.
71 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
72 * from skb->h.raw to the end and to record the checksum
73 * at skb->h.raw+skb->csum.
75 * Device must show its capabilities in dev->features, set
76 * at device setup time.
77 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
79 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
80 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
81 * TCP/UDP over IPv4. Sigh. Vendors like this
82 * way by an unknown reason. Though, see comment above
83 * about CHECKSUM_UNNECESSARY. 8)
85 * Any questions? No questions, good. --ANK
90 #ifdef CONFIG_NETFILTER
93 void (*destroy
)(struct nf_conntrack
*);
96 #ifdef CONFIG_BRIDGE_NETFILTER
97 struct nf_bridge_info
{
99 struct net_device
*physindev
;
100 struct net_device
*physoutdev
;
101 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
102 struct net_device
*netoutdev
;
105 unsigned long data
[32 / sizeof(unsigned long)];
111 struct sk_buff_head
{
112 /* These two members must be first. */
113 struct sk_buff
*next
;
114 struct sk_buff
*prev
;
122 /* To allow 64K frame to be packed as single skb without frag_list */
123 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
125 typedef struct skb_frag_struct skb_frag_t
;
127 struct skb_frag_struct
{
133 /* This data is invariant across clones and lives at
134 * the end of the header data, ie. at skb->end.
136 struct skb_shared_info
{
138 unsigned short nr_frags
;
139 unsigned short gso_size
;
140 /* Warning: this field is not always filled in (UFO)! */
141 unsigned short gso_segs
;
142 unsigned short gso_type
;
144 struct sk_buff
*frag_list
;
145 skb_frag_t frags
[MAX_SKB_FRAGS
];
148 /* We divide dataref into two halves. The higher 16 bits hold references
149 * to the payload part of skb->data. The lower 16 bits hold references to
150 * the entire skb->data. It is up to the users of the skb to agree on
151 * where the payload starts.
153 * All users must obey the rule that the skb->data reference count must be
154 * greater than or equal to the payload reference count.
156 * Holding a reference to the payload part means that the user does not
157 * care about modifications to the header part of skb->data.
159 #define SKB_DATAREF_SHIFT 16
160 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
164 SKB_FCLONE_UNAVAILABLE
,
170 SKB_GSO_TCPV4
= 1 << 0,
171 SKB_GSO_UDP
= 1 << 1,
173 /* This indicates the skb is from an untrusted source. */
174 SKB_GSO_DODGY
= 1 << 2,
176 /* This indicates the tcp segment has CWR set. */
177 SKB_GSO_TCP_ECN
= 1 << 3,
179 SKB_GSO_TCPV6
= 1 << 4,
183 * struct sk_buff - socket buffer
184 * @next: Next buffer in list
185 * @prev: Previous buffer in list
186 * @sk: Socket we are owned by
187 * @tstamp: Time we arrived
188 * @dev: Device we arrived on/are leaving by
189 * @iif: ifindex of device we arrived on
190 * @h: Transport layer header
191 * @nh: Network layer header
192 * @mac: Link layer header
193 * @dst: destination entry
194 * @sp: the security path, used for xfrm
195 * @cb: Control buffer. Free for use by every layer. Put private vars here
196 * @len: Length of actual data
197 * @data_len: Data length
198 * @mac_len: Length of link layer header
200 * @local_df: allow local fragmentation
201 * @cloned: Head may be cloned (check refcnt to be sure)
202 * @nohdr: Payload reference only, must not modify header
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
214 * @destructor: Destruct function
215 * @mark: Generic packet mark
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 * @dma_cookie: a cookie to one of several possible DMA operations
224 * done by skb DMA functions
225 * @secmark: security marking
229 /* These two members must be first. */
230 struct sk_buff
*next
;
231 struct sk_buff
*prev
;
235 struct net_device
*dev
;
237 /* 4 byte hole on 64 bit*/
242 struct icmphdr
*icmph
;
243 struct igmphdr
*igmph
;
245 struct ipv6hdr
*ipv6h
;
251 struct ipv6hdr
*ipv6h
;
260 struct dst_entry
*dst
;
264 * This is the control buffer. It is free to use for every
265 * layer. Please put your private variables there. If you
266 * want to keep them across layers you have to do a skb_clone()
267 * first. This is owned by whoever has the skb queued ATM.
289 void (*destructor
)(struct sk_buff
*skb
);
290 #ifdef CONFIG_NETFILTER
291 struct nf_conntrack
*nfct
;
292 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
293 struct sk_buff
*nfct_reasm
;
295 #ifdef CONFIG_BRIDGE_NETFILTER
296 struct nf_bridge_info
*nf_bridge
;
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 */
305 #ifdef CONFIG_NET_DMA
306 dma_cookie_t dma_cookie
;
308 #ifdef CONFIG_NETWORK_SECMARK
314 /* These elements must be at the end, see alloc_skb() for details. */
315 unsigned int truesize
;
325 * Handling routines are only of interest to the kernel
327 #include <linux/slab.h>
329 #include <asm/system.h>
331 extern void kfree_skb(struct sk_buff
*skb
);
332 extern void __kfree_skb(struct sk_buff
*skb
);
333 extern struct sk_buff
*__alloc_skb(unsigned int size
,
334 gfp_t priority
, int fclone
, int node
);
335 static inline struct sk_buff
*alloc_skb(unsigned int size
,
338 return __alloc_skb(size
, priority
, 0, -1);
341 static inline struct sk_buff
*alloc_skb_fclone(unsigned int size
,
344 return __alloc_skb(size
, priority
, 1, -1);
347 extern void kfree_skbmem(struct sk_buff
*skb
);
348 extern struct sk_buff
*skb_clone(struct sk_buff
*skb
,
350 extern struct sk_buff
*skb_copy(const struct sk_buff
*skb
,
352 extern struct sk_buff
*pskb_copy(struct sk_buff
*skb
,
354 extern int pskb_expand_head(struct sk_buff
*skb
,
355 int nhead
, int ntail
,
357 extern struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
,
358 unsigned int headroom
);
359 extern struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
360 int newheadroom
, int newtailroom
,
362 extern int skb_pad(struct sk_buff
*skb
, int pad
);
363 #define dev_kfree_skb(a) kfree_skb(a)
364 extern void skb_over_panic(struct sk_buff
*skb
, int len
,
366 extern void skb_under_panic(struct sk_buff
*skb
, int len
,
368 extern void skb_truesize_bug(struct sk_buff
*skb
);
370 static inline void skb_truesize_check(struct sk_buff
*skb
)
372 if (unlikely((int)skb
->truesize
< sizeof(struct sk_buff
) + skb
->len
))
373 skb_truesize_bug(skb
);
376 extern int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
377 int getfrag(void *from
, char *to
, int offset
,
378 int len
,int odd
, struct sk_buff
*skb
),
379 void *from
, int length
);
386 __u32 stepped_offset
;
387 struct sk_buff
*root_skb
;
388 struct sk_buff
*cur_skb
;
392 extern void skb_prepare_seq_read(struct sk_buff
*skb
,
393 unsigned int from
, unsigned int to
,
394 struct skb_seq_state
*st
);
395 extern unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
396 struct skb_seq_state
*st
);
397 extern void skb_abort_seq_read(struct skb_seq_state
*st
);
399 extern unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
400 unsigned int to
, struct ts_config
*config
,
401 struct ts_state
*state
);
404 #define skb_shinfo(SKB) ((struct skb_shared_info *)((SKB)->end))
407 * skb_queue_empty - check if a queue is empty
410 * Returns true if the queue is empty, false otherwise.
412 static inline int skb_queue_empty(const struct sk_buff_head
*list
)
414 return list
->next
== (struct sk_buff
*)list
;
418 * skb_get - reference buffer
419 * @skb: buffer to reference
421 * Makes another reference to a socket buffer and returns a pointer
424 static inline struct sk_buff
*skb_get(struct sk_buff
*skb
)
426 atomic_inc(&skb
->users
);
431 * If users == 1, we are the only owner and are can avoid redundant
436 * skb_cloned - is the buffer a clone
437 * @skb: buffer to check
439 * Returns true if the buffer was generated with skb_clone() and is
440 * one of multiple shared copies of the buffer. Cloned buffers are
441 * shared data so must not be written to under normal circumstances.
443 static inline int skb_cloned(const struct sk_buff
*skb
)
445 return skb
->cloned
&&
446 (atomic_read(&skb_shinfo(skb
)->dataref
) & SKB_DATAREF_MASK
) != 1;
450 * skb_header_cloned - is the header a clone
451 * @skb: buffer to check
453 * Returns true if modifying the header part of the buffer requires
454 * the data to be copied.
456 static inline int skb_header_cloned(const struct sk_buff
*skb
)
463 dataref
= atomic_read(&skb_shinfo(skb
)->dataref
);
464 dataref
= (dataref
& SKB_DATAREF_MASK
) - (dataref
>> SKB_DATAREF_SHIFT
);
469 * skb_header_release - release reference to header
470 * @skb: buffer to operate on
472 * Drop a reference to the header part of the buffer. This is done
473 * by acquiring a payload reference. You must not read from the header
474 * part of skb->data after this.
476 static inline void skb_header_release(struct sk_buff
*skb
)
480 atomic_add(1 << SKB_DATAREF_SHIFT
, &skb_shinfo(skb
)->dataref
);
484 * skb_shared - is the buffer shared
485 * @skb: buffer to check
487 * Returns true if more than one person has a reference to this
490 static inline int skb_shared(const struct sk_buff
*skb
)
492 return atomic_read(&skb
->users
) != 1;
496 * skb_share_check - check if buffer is shared and if so clone it
497 * @skb: buffer to check
498 * @pri: priority for memory allocation
500 * If the buffer is shared the buffer is cloned and the old copy
501 * drops a reference. A new clone with a single reference is returned.
502 * If the buffer is not shared the original buffer is returned. When
503 * being called from interrupt status or with spinlocks held pri must
506 * NULL is returned on a memory allocation failure.
508 static inline struct sk_buff
*skb_share_check(struct sk_buff
*skb
,
511 might_sleep_if(pri
& __GFP_WAIT
);
512 if (skb_shared(skb
)) {
513 struct sk_buff
*nskb
= skb_clone(skb
, pri
);
521 * Copy shared buffers into a new sk_buff. We effectively do COW on
522 * packets to handle cases where we have a local reader and forward
523 * and a couple of other messy ones. The normal one is tcpdumping
524 * a packet thats being forwarded.
528 * skb_unshare - make a copy of a shared buffer
529 * @skb: buffer to check
530 * @pri: priority for memory allocation
532 * If the socket buffer is a clone then this function creates a new
533 * copy of the data, drops a reference count on the old copy and returns
534 * the new copy with the reference count at 1. If the buffer is not a clone
535 * the original buffer is returned. When called with a spinlock held or
536 * from interrupt state @pri must be %GFP_ATOMIC
538 * %NULL is returned on a memory allocation failure.
540 static inline struct sk_buff
*skb_unshare(struct sk_buff
*skb
,
543 might_sleep_if(pri
& __GFP_WAIT
);
544 if (skb_cloned(skb
)) {
545 struct sk_buff
*nskb
= skb_copy(skb
, pri
);
546 kfree_skb(skb
); /* Free our shared copy */
554 * @list_: list to peek at
556 * Peek an &sk_buff. Unlike most other operations you _MUST_
557 * be careful with this one. A peek leaves the buffer on the
558 * list and someone else may run off with it. You must hold
559 * the appropriate locks or have a private queue to do this.
561 * Returns %NULL for an empty list or a pointer to the head element.
562 * The reference count is not incremented and the reference is therefore
563 * volatile. Use with caution.
565 static inline struct sk_buff
*skb_peek(struct sk_buff_head
*list_
)
567 struct sk_buff
*list
= ((struct sk_buff
*)list_
)->next
;
568 if (list
== (struct sk_buff
*)list_
)
575 * @list_: list to peek at
577 * Peek an &sk_buff. Unlike most other operations you _MUST_
578 * be careful with this one. A peek leaves the buffer on the
579 * list and someone else may run off with it. You must hold
580 * the appropriate locks or have a private queue to do this.
582 * Returns %NULL for an empty list or a pointer to the tail element.
583 * The reference count is not incremented and the reference is therefore
584 * volatile. Use with caution.
586 static inline struct sk_buff
*skb_peek_tail(struct sk_buff_head
*list_
)
588 struct sk_buff
*list
= ((struct sk_buff
*)list_
)->prev
;
589 if (list
== (struct sk_buff
*)list_
)
595 * skb_queue_len - get queue length
596 * @list_: list to measure
598 * Return the length of an &sk_buff queue.
600 static inline __u32
skb_queue_len(const struct sk_buff_head
*list_
)
606 * This function creates a split out lock class for each invocation;
607 * this is needed for now since a whole lot of users of the skb-queue
608 * infrastructure in drivers have different locking usage (in hardirq)
609 * than the networking core (in softirq only). In the long run either the
610 * network layer or drivers should need annotation to consolidate the
611 * main types of usage into 3 classes.
613 static inline void skb_queue_head_init(struct sk_buff_head
*list
)
615 spin_lock_init(&list
->lock
);
616 list
->prev
= list
->next
= (struct sk_buff
*)list
;
620 static inline void skb_queue_head_init_class(struct sk_buff_head
*list
,
621 struct lock_class_key
*class)
623 skb_queue_head_init(list
);
624 lockdep_set_class(&list
->lock
, class);
628 * Insert an sk_buff at the start of a list.
630 * The "__skb_xxxx()" functions are the non-atomic ones that
631 * can only be called with interrupts disabled.
635 * __skb_queue_after - queue a buffer at the list head
637 * @prev: place after this buffer
638 * @newsk: buffer to queue
640 * Queue a buffer int the middle of a list. This function takes no locks
641 * and you must therefore hold required locks before calling it.
643 * A buffer cannot be placed on two lists at the same time.
645 static inline void __skb_queue_after(struct sk_buff_head
*list
,
646 struct sk_buff
*prev
,
647 struct sk_buff
*newsk
)
649 struct sk_buff
*next
;
655 next
->prev
= prev
->next
= newsk
;
659 * __skb_queue_head - queue a buffer at the list head
661 * @newsk: buffer to queue
663 * Queue a buffer at the start of a list. This function takes no locks
664 * and you must therefore hold required locks before calling it.
666 * A buffer cannot be placed on two lists at the same time.
668 extern void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
);
669 static inline void __skb_queue_head(struct sk_buff_head
*list
,
670 struct sk_buff
*newsk
)
672 __skb_queue_after(list
, (struct sk_buff
*)list
, newsk
);
676 * __skb_queue_tail - queue a buffer at the list tail
678 * @newsk: buffer to queue
680 * Queue a buffer at the end of a list. This function takes no locks
681 * and you must therefore hold required locks before calling it.
683 * A buffer cannot be placed on two lists at the same time.
685 extern void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
);
686 static inline void __skb_queue_tail(struct sk_buff_head
*list
,
687 struct sk_buff
*newsk
)
689 struct sk_buff
*prev
, *next
;
692 next
= (struct sk_buff
*)list
;
696 next
->prev
= prev
->next
= newsk
;
701 * __skb_dequeue - remove from the head of the queue
702 * @list: list to dequeue from
704 * Remove the head of the list. This function does not take any locks
705 * so must be used with appropriate locks held only. The head item is
706 * returned or %NULL if the list is empty.
708 extern struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
);
709 static inline struct sk_buff
*__skb_dequeue(struct sk_buff_head
*list
)
711 struct sk_buff
*next
, *prev
, *result
;
713 prev
= (struct sk_buff
*) list
;
722 result
->next
= result
->prev
= NULL
;
729 * Insert a packet on a list.
731 extern void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
);
732 static inline void __skb_insert(struct sk_buff
*newsk
,
733 struct sk_buff
*prev
, struct sk_buff
*next
,
734 struct sk_buff_head
*list
)
738 next
->prev
= prev
->next
= newsk
;
743 * Place a packet after a given packet in a list.
745 extern void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
);
746 static inline void __skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
748 __skb_insert(newsk
, old
, old
->next
, list
);
752 * remove sk_buff from list. _Must_ be called atomically, and with
755 extern void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
);
756 static inline void __skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
758 struct sk_buff
*next
, *prev
;
763 skb
->next
= skb
->prev
= NULL
;
769 /* XXX: more streamlined implementation */
772 * __skb_dequeue_tail - remove from the tail of the queue
773 * @list: list to dequeue from
775 * Remove the tail of the list. This function does not take any locks
776 * so must be used with appropriate locks held only. The tail item is
777 * returned or %NULL if the list is empty.
779 extern struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
);
780 static inline struct sk_buff
*__skb_dequeue_tail(struct sk_buff_head
*list
)
782 struct sk_buff
*skb
= skb_peek_tail(list
);
784 __skb_unlink(skb
, list
);
789 static inline int skb_is_nonlinear(const struct sk_buff
*skb
)
791 return skb
->data_len
;
794 static inline unsigned int skb_headlen(const struct sk_buff
*skb
)
796 return skb
->len
- skb
->data_len
;
799 static inline int skb_pagelen(const struct sk_buff
*skb
)
803 for (i
= (int)skb_shinfo(skb
)->nr_frags
- 1; i
>= 0; i
--)
804 len
+= skb_shinfo(skb
)->frags
[i
].size
;
805 return len
+ skb_headlen(skb
);
808 static inline void skb_fill_page_desc(struct sk_buff
*skb
, int i
,
809 struct page
*page
, int off
, int size
)
811 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
814 frag
->page_offset
= off
;
816 skb_shinfo(skb
)->nr_frags
= i
+ 1;
819 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
820 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list)
821 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
824 * Add data to an sk_buff
826 static inline unsigned char *__skb_put(struct sk_buff
*skb
, unsigned int len
)
828 unsigned char *tmp
= skb
->tail
;
829 SKB_LINEAR_ASSERT(skb
);
836 * skb_put - add data to a buffer
837 * @skb: buffer to use
838 * @len: amount of data to add
840 * This function extends the used data area of the buffer. If this would
841 * exceed the total buffer size the kernel will panic. A pointer to the
842 * first byte of the extra data is returned.
844 static inline unsigned char *skb_put(struct sk_buff
*skb
, unsigned int len
)
846 unsigned char *tmp
= skb
->tail
;
847 SKB_LINEAR_ASSERT(skb
);
850 if (unlikely(skb
->tail
>skb
->end
))
851 skb_over_panic(skb
, len
, current_text_addr());
855 static inline unsigned char *__skb_push(struct sk_buff
*skb
, unsigned int len
)
863 * skb_push - add data to the start of a buffer
864 * @skb: buffer to use
865 * @len: amount of data to add
867 * This function extends the used data area of the buffer at the buffer
868 * start. If this would exceed the total buffer headroom the kernel will
869 * panic. A pointer to the first byte of the extra data is returned.
871 static inline unsigned char *skb_push(struct sk_buff
*skb
, unsigned int len
)
875 if (unlikely(skb
->data
<skb
->head
))
876 skb_under_panic(skb
, len
, current_text_addr());
880 static inline unsigned char *__skb_pull(struct sk_buff
*skb
, unsigned int len
)
883 BUG_ON(skb
->len
< skb
->data_len
);
884 return skb
->data
+= len
;
888 * skb_pull - remove data from the start of a buffer
889 * @skb: buffer to use
890 * @len: amount of data to remove
892 * This function removes data from the start of a buffer, returning
893 * the memory to the headroom. A pointer to the next data in the buffer
894 * is returned. Once the data has been pulled future pushes will overwrite
897 static inline unsigned char *skb_pull(struct sk_buff
*skb
, unsigned int len
)
899 return unlikely(len
> skb
->len
) ? NULL
: __skb_pull(skb
, len
);
902 extern unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
);
904 static inline unsigned char *__pskb_pull(struct sk_buff
*skb
, unsigned int len
)
906 if (len
> skb_headlen(skb
) &&
907 !__pskb_pull_tail(skb
, len
-skb_headlen(skb
)))
910 return skb
->data
+= len
;
913 static inline unsigned char *pskb_pull(struct sk_buff
*skb
, unsigned int len
)
915 return unlikely(len
> skb
->len
) ? NULL
: __pskb_pull(skb
, len
);
918 static inline int pskb_may_pull(struct sk_buff
*skb
, unsigned int len
)
920 if (likely(len
<= skb_headlen(skb
)))
922 if (unlikely(len
> skb
->len
))
924 return __pskb_pull_tail(skb
, len
-skb_headlen(skb
)) != NULL
;
928 * skb_headroom - bytes at buffer head
929 * @skb: buffer to check
931 * Return the number of bytes of free space at the head of an &sk_buff.
933 static inline int skb_headroom(const struct sk_buff
*skb
)
935 return skb
->data
- skb
->head
;
939 * skb_tailroom - bytes at buffer end
940 * @skb: buffer to check
942 * Return the number of bytes of free space at the tail of an sk_buff
944 static inline int skb_tailroom(const struct sk_buff
*skb
)
946 return skb_is_nonlinear(skb
) ? 0 : skb
->end
- skb
->tail
;
950 * skb_reserve - adjust headroom
951 * @skb: buffer to alter
952 * @len: bytes to move
954 * Increase the headroom of an empty &sk_buff by reducing the tail
955 * room. This is only allowed for an empty buffer.
957 static inline void skb_reserve(struct sk_buff
*skb
, int len
)
963 static inline unsigned char *skb_mac_header(const struct sk_buff
*skb
)
968 static inline int skb_mac_header_was_set(const struct sk_buff
*skb
)
970 return skb
->mac
.raw
!= NULL
;
973 static inline void skb_reset_mac_header(struct sk_buff
*skb
)
975 skb
->mac
.raw
= skb
->data
;
978 static inline void skb_set_mac_header(struct sk_buff
*skb
, const int offset
)
980 skb
->mac
.raw
= skb
->data
+ offset
;
984 * CPUs often take a performance hit when accessing unaligned memory
985 * locations. The actual performance hit varies, it can be small if the
986 * hardware handles it or large if we have to take an exception and fix it
989 * Since an ethernet header is 14 bytes network drivers often end up with
990 * the IP header at an unaligned offset. The IP header can be aligned by
991 * shifting the start of the packet by 2 bytes. Drivers should do this
994 * skb_reserve(NET_IP_ALIGN);
996 * The downside to this alignment of the IP header is that the DMA is now
997 * unaligned. On some architectures the cost of an unaligned DMA is high
998 * and this cost outweighs the gains made by aligning the IP header.
1000 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1003 #ifndef NET_IP_ALIGN
1004 #define NET_IP_ALIGN 2
1008 * The networking layer reserves some headroom in skb data (via
1009 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1010 * the header has to grow. In the default case, if the header has to grow
1011 * 16 bytes or less we avoid the reallocation.
1013 * Unfortunately this headroom changes the DMA alignment of the resulting
1014 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1015 * on some architectures. An architecture can override this value,
1016 * perhaps setting it to a cacheline in size (since that will maintain
1017 * cacheline alignment of the DMA). It must be a power of 2.
1019 * Various parts of the networking layer expect at least 16 bytes of
1020 * headroom, you should not reduce this.
1023 #define NET_SKB_PAD 16
1026 extern int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
);
1028 static inline void __skb_trim(struct sk_buff
*skb
, unsigned int len
)
1030 if (unlikely(skb
->data_len
)) {
1035 skb
->tail
= skb
->data
+ len
;
1039 * skb_trim - remove end from a buffer
1040 * @skb: buffer to alter
1043 * Cut the length of a buffer down by removing data from the tail. If
1044 * the buffer is already under the length specified it is not modified.
1045 * The skb must be linear.
1047 static inline void skb_trim(struct sk_buff
*skb
, unsigned int len
)
1050 __skb_trim(skb
, len
);
1054 static inline int __pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1057 return ___pskb_trim(skb
, len
);
1058 __skb_trim(skb
, len
);
1062 static inline int pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1064 return (len
< skb
->len
) ? __pskb_trim(skb
, len
) : 0;
1068 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1069 * @skb: buffer to alter
1072 * This is identical to pskb_trim except that the caller knows that
1073 * the skb is not cloned so we should never get an error due to out-
1076 static inline void pskb_trim_unique(struct sk_buff
*skb
, unsigned int len
)
1078 int err
= pskb_trim(skb
, len
);
1083 * skb_orphan - orphan a buffer
1084 * @skb: buffer to orphan
1086 * If a buffer currently has an owner then we call the owner's
1087 * destructor function and make the @skb unowned. The buffer continues
1088 * to exist but is no longer charged to its former owner.
1090 static inline void skb_orphan(struct sk_buff
*skb
)
1092 if (skb
->destructor
)
1093 skb
->destructor(skb
);
1094 skb
->destructor
= NULL
;
1099 * __skb_queue_purge - empty a list
1100 * @list: list to empty
1102 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1103 * the list and one reference dropped. This function does not take the
1104 * list lock and the caller must hold the relevant locks to use it.
1106 extern void skb_queue_purge(struct sk_buff_head
*list
);
1107 static inline void __skb_queue_purge(struct sk_buff_head
*list
)
1109 struct sk_buff
*skb
;
1110 while ((skb
= __skb_dequeue(list
)) != NULL
)
1115 * __dev_alloc_skb - allocate an skbuff for receiving
1116 * @length: length to allocate
1117 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1119 * Allocate a new &sk_buff and assign it a usage count of one. The
1120 * buffer has unspecified headroom built in. Users should allocate
1121 * the headroom they think they need without accounting for the
1122 * built in space. The built in space is used for optimisations.
1124 * %NULL is returned if there is no free memory.
1126 static inline struct sk_buff
*__dev_alloc_skb(unsigned int length
,
1129 struct sk_buff
*skb
= alloc_skb(length
+ NET_SKB_PAD
, gfp_mask
);
1131 skb_reserve(skb
, NET_SKB_PAD
);
1136 * dev_alloc_skb - allocate an skbuff for receiving
1137 * @length: length to allocate
1139 * Allocate a new &sk_buff and assign it a usage count of one. The
1140 * buffer has unspecified headroom built in. Users should allocate
1141 * the headroom they think they need without accounting for the
1142 * built in space. The built in space is used for optimisations.
1144 * %NULL is returned if there is no free memory. Although this function
1145 * allocates memory it can be called from an interrupt.
1147 static inline struct sk_buff
*dev_alloc_skb(unsigned int length
)
1149 return __dev_alloc_skb(length
, GFP_ATOMIC
);
1152 extern struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
,
1153 unsigned int length
, gfp_t gfp_mask
);
1156 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1157 * @dev: network device to receive on
1158 * @length: length to allocate
1160 * Allocate a new &sk_buff and assign it a usage count of one. The
1161 * buffer has unspecified headroom built in. Users should allocate
1162 * the headroom they think they need without accounting for the
1163 * built in space. The built in space is used for optimisations.
1165 * %NULL is returned if there is no free memory. Although this function
1166 * allocates memory it can be called from an interrupt.
1168 static inline struct sk_buff
*netdev_alloc_skb(struct net_device
*dev
,
1169 unsigned int length
)
1171 return __netdev_alloc_skb(dev
, length
, GFP_ATOMIC
);
1175 * skb_cow - copy header of skb when it is required
1176 * @skb: buffer to cow
1177 * @headroom: needed headroom
1179 * If the skb passed lacks sufficient headroom or its data part
1180 * is shared, data is reallocated. If reallocation fails, an error
1181 * is returned and original skb is not changed.
1183 * The result is skb with writable area skb->head...skb->tail
1184 * and at least @headroom of space at head.
1186 static inline int skb_cow(struct sk_buff
*skb
, unsigned int headroom
)
1188 int delta
= (headroom
> NET_SKB_PAD
? headroom
: NET_SKB_PAD
) -
1194 if (delta
|| skb_cloned(skb
))
1195 return pskb_expand_head(skb
, (delta
+ (NET_SKB_PAD
-1)) &
1196 ~(NET_SKB_PAD
-1), 0, GFP_ATOMIC
);
1201 * skb_padto - pad an skbuff up to a minimal size
1202 * @skb: buffer to pad
1203 * @len: minimal length
1205 * Pads up a buffer to ensure the trailing bytes exist and are
1206 * blanked. If the buffer already contains sufficient data it
1207 * is untouched. Otherwise it is extended. Returns zero on
1208 * success. The skb is freed on error.
1211 static inline int skb_padto(struct sk_buff
*skb
, unsigned int len
)
1213 unsigned int size
= skb
->len
;
1214 if (likely(size
>= len
))
1216 return skb_pad(skb
, len
-size
);
1219 static inline int skb_add_data(struct sk_buff
*skb
,
1220 char __user
*from
, int copy
)
1222 const int off
= skb
->len
;
1224 if (skb
->ip_summed
== CHECKSUM_NONE
) {
1226 __wsum csum
= csum_and_copy_from_user(from
, skb_put(skb
, copy
),
1229 skb
->csum
= csum_block_add(skb
->csum
, csum
, off
);
1232 } else if (!copy_from_user(skb_put(skb
, copy
), from
, copy
))
1235 __skb_trim(skb
, off
);
1239 static inline int skb_can_coalesce(struct sk_buff
*skb
, int i
,
1240 struct page
*page
, int off
)
1243 struct skb_frag_struct
*frag
= &skb_shinfo(skb
)->frags
[i
- 1];
1245 return page
== frag
->page
&&
1246 off
== frag
->page_offset
+ frag
->size
;
1251 static inline int __skb_linearize(struct sk_buff
*skb
)
1253 return __pskb_pull_tail(skb
, skb
->data_len
) ? 0 : -ENOMEM
;
1257 * skb_linearize - convert paged skb to linear one
1258 * @skb: buffer to linarize
1260 * If there is no free memory -ENOMEM is returned, otherwise zero
1261 * is returned and the old skb data released.
1263 static inline int skb_linearize(struct sk_buff
*skb
)
1265 return skb_is_nonlinear(skb
) ? __skb_linearize(skb
) : 0;
1269 * skb_linearize_cow - make sure skb is linear and writable
1270 * @skb: buffer to process
1272 * If there is no free memory -ENOMEM is returned, otherwise zero
1273 * is returned and the old skb data released.
1275 static inline int skb_linearize_cow(struct sk_buff
*skb
)
1277 return skb_is_nonlinear(skb
) || skb_cloned(skb
) ?
1278 __skb_linearize(skb
) : 0;
1282 * skb_postpull_rcsum - update checksum for received skb after pull
1283 * @skb: buffer to update
1284 * @start: start of data before pull
1285 * @len: length of data pulled
1287 * After doing a pull on a received packet, you need to call this to
1288 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1289 * CHECKSUM_NONE so that it can be recomputed from scratch.
1292 static inline void skb_postpull_rcsum(struct sk_buff
*skb
,
1293 const void *start
, unsigned int len
)
1295 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
1296 skb
->csum
= csum_sub(skb
->csum
, csum_partial(start
, len
, 0));
1299 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
);
1302 * pskb_trim_rcsum - trim received skb and update checksum
1303 * @skb: buffer to trim
1306 * This is exactly the same as pskb_trim except that it ensures the
1307 * checksum of received packets are still valid after the operation.
1310 static inline int pskb_trim_rcsum(struct sk_buff
*skb
, unsigned int len
)
1312 if (likely(len
>= skb
->len
))
1314 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
1315 skb
->ip_summed
= CHECKSUM_NONE
;
1316 return __pskb_trim(skb
, len
);
1319 #define skb_queue_walk(queue, skb) \
1320 for (skb = (queue)->next; \
1321 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1324 #define skb_queue_reverse_walk(queue, skb) \
1325 for (skb = (queue)->prev; \
1326 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1330 extern struct sk_buff
*skb_recv_datagram(struct sock
*sk
, unsigned flags
,
1331 int noblock
, int *err
);
1332 extern unsigned int datagram_poll(struct file
*file
, struct socket
*sock
,
1333 struct poll_table_struct
*wait
);
1334 extern int skb_copy_datagram_iovec(const struct sk_buff
*from
,
1335 int offset
, struct iovec
*to
,
1337 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff
*skb
,
1340 extern void skb_free_datagram(struct sock
*sk
, struct sk_buff
*skb
);
1341 extern void skb_kill_datagram(struct sock
*sk
, struct sk_buff
*skb
,
1342 unsigned int flags
);
1343 extern __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
1344 int len
, __wsum csum
);
1345 extern int skb_copy_bits(const struct sk_buff
*skb
, int offset
,
1347 extern int skb_store_bits(const struct sk_buff
*skb
, int offset
,
1348 void *from
, int len
);
1349 extern __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
,
1350 int offset
, u8
*to
, int len
,
1352 extern void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
);
1353 extern void skb_split(struct sk_buff
*skb
,
1354 struct sk_buff
*skb1
, const u32 len
);
1356 extern struct sk_buff
*skb_segment(struct sk_buff
*skb
, int features
);
1358 static inline void *skb_header_pointer(const struct sk_buff
*skb
, int offset
,
1359 int len
, void *buffer
)
1361 int hlen
= skb_headlen(skb
);
1363 if (hlen
- offset
>= len
)
1364 return skb
->data
+ offset
;
1366 if (skb_copy_bits(skb
, offset
, buffer
, len
) < 0)
1372 extern void skb_init(void);
1373 extern void skb_add_mtu(int mtu
);
1376 * skb_get_timestamp - get timestamp from a skb
1377 * @skb: skb to get stamp from
1378 * @stamp: pointer to struct timeval to store stamp in
1380 * Timestamps are stored in the skb as offsets to a base timestamp.
1381 * This function converts the offset back to a struct timeval and stores
1384 static inline void skb_get_timestamp(const struct sk_buff
*skb
, struct timeval
*stamp
)
1386 *stamp
= ktime_to_timeval(skb
->tstamp
);
1389 static inline void __net_timestamp(struct sk_buff
*skb
)
1391 skb
->tstamp
= ktime_get_real();
1395 extern __sum16
__skb_checksum_complete_head(struct sk_buff
*skb
, int len
);
1396 extern __sum16
__skb_checksum_complete(struct sk_buff
*skb
);
1399 * skb_checksum_complete - Calculate checksum of an entire packet
1400 * @skb: packet to process
1402 * This function calculates the checksum over the entire packet plus
1403 * the value of skb->csum. The latter can be used to supply the
1404 * checksum of a pseudo header as used by TCP/UDP. It returns the
1407 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
1408 * this function can be used to verify that checksum on received
1409 * packets. In that case the function should return zero if the
1410 * checksum is correct. In particular, this function will return zero
1411 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
1412 * hardware has already verified the correctness of the checksum.
1414 static inline unsigned int skb_checksum_complete(struct sk_buff
*skb
)
1416 return skb
->ip_summed
!= CHECKSUM_UNNECESSARY
&&
1417 __skb_checksum_complete(skb
);
1420 #ifdef CONFIG_NETFILTER
1421 static inline void nf_conntrack_put(struct nf_conntrack
*nfct
)
1423 if (nfct
&& atomic_dec_and_test(&nfct
->use
))
1424 nfct
->destroy(nfct
);
1426 static inline void nf_conntrack_get(struct nf_conntrack
*nfct
)
1429 atomic_inc(&nfct
->use
);
1431 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1432 static inline void nf_conntrack_get_reasm(struct sk_buff
*skb
)
1435 atomic_inc(&skb
->users
);
1437 static inline void nf_conntrack_put_reasm(struct sk_buff
*skb
)
1443 #ifdef CONFIG_BRIDGE_NETFILTER
1444 static inline void nf_bridge_put(struct nf_bridge_info
*nf_bridge
)
1446 if (nf_bridge
&& atomic_dec_and_test(&nf_bridge
->use
))
1449 static inline void nf_bridge_get(struct nf_bridge_info
*nf_bridge
)
1452 atomic_inc(&nf_bridge
->use
);
1454 #endif /* CONFIG_BRIDGE_NETFILTER */
1455 static inline void nf_reset(struct sk_buff
*skb
)
1457 nf_conntrack_put(skb
->nfct
);
1459 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1460 nf_conntrack_put_reasm(skb
->nfct_reasm
);
1461 skb
->nfct_reasm
= NULL
;
1463 #ifdef CONFIG_BRIDGE_NETFILTER
1464 nf_bridge_put(skb
->nf_bridge
);
1465 skb
->nf_bridge
= NULL
;
1469 #else /* CONFIG_NETFILTER */
1470 static inline void nf_reset(struct sk_buff
*skb
) {}
1471 #endif /* CONFIG_NETFILTER */
1473 #ifdef CONFIG_NETWORK_SECMARK
1474 static inline void skb_copy_secmark(struct sk_buff
*to
, const struct sk_buff
*from
)
1476 to
->secmark
= from
->secmark
;
1479 static inline void skb_init_secmark(struct sk_buff
*skb
)
1484 static inline void skb_copy_secmark(struct sk_buff
*to
, const struct sk_buff
*from
)
1487 static inline void skb_init_secmark(struct sk_buff
*skb
)
1491 static inline int skb_is_gso(const struct sk_buff
*skb
)
1493 return skb_shinfo(skb
)->gso_size
;
1496 #endif /* __KERNEL__ */
1497 #endif /* _LINUX_SKBUFF_H */