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/kmemcheck.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/net.h>
27 #include <linux/textsearch.h>
28 #include <net/checksum.h>
29 #include <linux/rcupdate.h>
30 #include <linux/dmaengine.h>
31 #include <linux/hrtimer.h>
33 /* Don't change this without changing skb_csum_unnecessary! */
34 #define CHECKSUM_NONE 0
35 #define CHECKSUM_UNNECESSARY 1
36 #define CHECKSUM_COMPLETE 2
37 #define CHECKSUM_PARTIAL 3
39 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
40 ~(SMP_CACHE_BYTES - 1))
41 #define SKB_WITH_OVERHEAD(X) \
42 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
43 #define SKB_MAX_ORDER(X, ORDER) \
44 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
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.
50 * NONE: device failed to checksum this packet.
51 * skb->csum is undefined.
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)
59 * COMPLETE: 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 COMPLETE,
65 * PARTIAL: identical to the case for output below. This may occur
66 * on a packet received directly from another Linux OS, e.g.,
67 * a virtualised Linux kernel on the same host. The packet can
68 * be treated in the same way as UNNECESSARY except that on
69 * output (i.e., forwarding) the checksum must be filled in
70 * by the OS or the hardware.
72 * B. Checksumming on output.
74 * NONE: skb is checksummed by protocol or csum is not required.
76 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
77 * from skb->csum_start to the end and to record the checksum
78 * at skb->csum_start + skb->csum_offset.
80 * Device must show its capabilities in dev->features, set
81 * at device setup time.
82 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
84 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
85 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
86 * TCP/UDP over IPv4. Sigh. Vendors like this
87 * way by an unknown reason. Though, see comment above
88 * about CHECKSUM_UNNECESSARY. 8)
89 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
91 * Any questions? No questions, good. --ANK
96 struct pipe_inode_info
;
98 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
104 #ifdef CONFIG_BRIDGE_NETFILTER
105 struct nf_bridge_info
{
107 struct net_device
*physindev
;
108 struct net_device
*physoutdev
;
110 unsigned long data
[32 / sizeof(unsigned long)];
114 struct sk_buff_head
{
115 /* These two members must be first. */
116 struct sk_buff
*next
;
117 struct sk_buff
*prev
;
125 /* To allow 64K frame to be packed as single skb without frag_list */
126 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
128 typedef struct skb_frag_struct skb_frag_t
;
130 struct skb_frag_struct
{
132 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
141 #define HAVE_HW_TIME_STAMP
144 * struct skb_shared_hwtstamps - hardware time stamps
145 * @hwtstamp: hardware time stamp transformed into duration
146 * since arbitrary point in time
147 * @syststamp: hwtstamp transformed to system time base
149 * Software time stamps generated by ktime_get_real() are stored in
150 * skb->tstamp. The relation between the different kinds of time
151 * stamps is as follows:
153 * syststamp and tstamp can be compared against each other in
154 * arbitrary combinations. The accuracy of a
155 * syststamp/tstamp/"syststamp from other device" comparison is
156 * limited by the accuracy of the transformation into system time
157 * base. This depends on the device driver and its underlying
160 * hwtstamps can only be compared against other hwtstamps from
163 * This structure is attached to packets as part of the
164 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
166 struct skb_shared_hwtstamps
{
171 /* Definitions for tx_flags in struct skb_shared_info */
173 /* generate hardware time stamp */
174 SKBTX_HW_TSTAMP
= 1 << 0,
176 /* generate software time stamp */
177 SKBTX_SW_TSTAMP
= 1 << 1,
179 /* device driver is going to provide hardware time stamp */
180 SKBTX_IN_PROGRESS
= 1 << 2,
182 /* ensure the originating sk reference is available on driver level */
183 SKBTX_DRV_NEEDS_SK_REF
= 1 << 3,
186 /* This data is invariant across clones and lives at
187 * the end of the header data, ie. at skb->end.
189 struct skb_shared_info
{
190 unsigned short nr_frags
;
191 unsigned short gso_size
;
192 /* Warning: this field is not always filled in (UFO)! */
193 unsigned short gso_segs
;
194 unsigned short gso_type
;
197 struct sk_buff
*frag_list
;
198 struct skb_shared_hwtstamps hwtstamps
;
201 * Warning : all fields before dataref are cleared in __alloc_skb()
205 /* Intermediate layers must ensure that destructor_arg
206 * remains valid until skb destructor */
207 void * destructor_arg
;
208 /* must be last field, see pskb_expand_head() */
209 skb_frag_t frags
[MAX_SKB_FRAGS
];
212 /* We divide dataref into two halves. The higher 16 bits hold references
213 * to the payload part of skb->data. The lower 16 bits hold references to
214 * the entire skb->data. A clone of a headerless skb holds the length of
215 * the header in skb->hdr_len.
217 * All users must obey the rule that the skb->data reference count must be
218 * greater than or equal to the payload reference count.
220 * Holding a reference to the payload part means that the user does not
221 * care about modifications to the header part of skb->data.
223 #define SKB_DATAREF_SHIFT 16
224 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
228 SKB_FCLONE_UNAVAILABLE
,
234 SKB_GSO_TCPV4
= 1 << 0,
235 SKB_GSO_UDP
= 1 << 1,
237 /* This indicates the skb is from an untrusted source. */
238 SKB_GSO_DODGY
= 1 << 2,
240 /* This indicates the tcp segment has CWR set. */
241 SKB_GSO_TCP_ECN
= 1 << 3,
243 SKB_GSO_TCPV6
= 1 << 4,
245 SKB_GSO_FCOE
= 1 << 5,
248 #if BITS_PER_LONG > 32
249 #define NET_SKBUFF_DATA_USES_OFFSET 1
252 #ifdef NET_SKBUFF_DATA_USES_OFFSET
253 typedef unsigned int sk_buff_data_t
;
255 typedef unsigned char *sk_buff_data_t
;
259 * struct sk_buff - socket buffer
260 * @next: Next buffer in list
261 * @prev: Previous buffer in list
262 * @sk: Socket we are owned by
263 * @tstamp: Time we arrived
264 * @dev: Device we arrived on/are leaving by
265 * @transport_header: Transport layer header
266 * @network_header: Network layer header
267 * @mac_header: Link layer header
268 * @_skb_refdst: destination entry (with norefcount bit)
269 * @sp: the security path, used for xfrm
270 * @cb: Control buffer. Free for use by every layer. Put private vars here
271 * @len: Length of actual data
272 * @data_len: Data length
273 * @mac_len: Length of link layer header
274 * @hdr_len: writable header length of cloned skb
275 * @csum: Checksum (must include start/offset pair)
276 * @csum_start: Offset from skb->head where checksumming should start
277 * @csum_offset: Offset from csum_start where checksum should be stored
278 * @local_df: allow local fragmentation
279 * @cloned: Head may be cloned (check refcnt to be sure)
280 * @nohdr: Payload reference only, must not modify header
281 * @pkt_type: Packet class
282 * @fclone: skbuff clone status
283 * @ip_summed: Driver fed us an IP checksum
284 * @priority: Packet queueing priority
285 * @users: User count - see {datagram,tcp}.c
286 * @protocol: Packet protocol from driver
287 * @truesize: Buffer size
288 * @head: Head of buffer
289 * @data: Data head pointer
290 * @tail: Tail pointer
292 * @destructor: Destruct function
293 * @mark: Generic packet mark
294 * @nfct: Associated connection, if any
295 * @ipvs_property: skbuff is owned by ipvs
296 * @peeked: this packet has been seen already, so stats have been
297 * done for it, don't do them again
298 * @nf_trace: netfilter packet trace flag
299 * @nfctinfo: Relationship of this skb to the connection
300 * @nfct_reasm: netfilter conntrack re-assembly pointer
301 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
302 * @skb_iif: ifindex of device we arrived on
303 * @rxhash: the packet hash computed on receive
304 * @queue_mapping: Queue mapping for multiqueue devices
305 * @tc_index: Traffic control index
306 * @tc_verd: traffic control verdict
307 * @ndisc_nodetype: router type (from link layer)
308 * @dma_cookie: a cookie to one of several possible DMA operations
309 * done by skb DMA functions
310 * @secmark: security marking
311 * @vlan_tci: vlan tag control information
315 /* These two members must be first. */
316 struct sk_buff
*next
;
317 struct sk_buff
*prev
;
322 struct net_device
*dev
;
325 * This is the control buffer. It is free to use for every
326 * layer. Please put your private variables there. If you
327 * want to keep them across layers you have to do a skb_clone()
328 * first. This is owned by whoever has the skb queued ATM.
330 char cb
[48] __aligned(8);
332 unsigned long _skb_refdst
;
348 kmemcheck_bitfield_begin(flags1
);
359 kmemcheck_bitfield_end(flags1
);
362 void (*destructor
)(struct sk_buff
*skb
);
363 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
364 struct nf_conntrack
*nfct
;
365 struct sk_buff
*nfct_reasm
;
367 #ifdef CONFIG_BRIDGE_NETFILTER
368 struct nf_bridge_info
*nf_bridge
;
372 #ifdef CONFIG_NET_SCHED
373 __u16 tc_index
; /* traffic control index */
374 #ifdef CONFIG_NET_CLS_ACT
375 __u16 tc_verd
; /* traffic control verdict */
381 kmemcheck_bitfield_begin(flags2
);
382 __u16 queue_mapping
:16;
383 #ifdef CONFIG_IPV6_NDISC_NODETYPE
384 __u8 ndisc_nodetype
:2,
387 __u8 deliver_no_wcard
:1;
390 kmemcheck_bitfield_end(flags2
);
394 #ifdef CONFIG_NET_DMA
395 dma_cookie_t dma_cookie
;
397 #ifdef CONFIG_NETWORK_SECMARK
407 sk_buff_data_t transport_header
;
408 sk_buff_data_t network_header
;
409 sk_buff_data_t mac_header
;
410 /* These elements must be at the end, see alloc_skb() for details. */
415 unsigned int truesize
;
421 * Handling routines are only of interest to the kernel
423 #include <linux/slab.h>
425 #include <asm/system.h>
428 * skb might have a dst pointer attached, refcounted or not.
429 * _skb_refdst low order bit is set if refcount was _not_ taken
431 #define SKB_DST_NOREF 1UL
432 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
435 * skb_dst - returns skb dst_entry
438 * Returns skb dst_entry, regardless of reference taken or not.
440 static inline struct dst_entry
*skb_dst(const struct sk_buff
*skb
)
442 /* If refdst was not refcounted, check we still are in a
443 * rcu_read_lock section
445 WARN_ON((skb
->_skb_refdst
& SKB_DST_NOREF
) &&
446 !rcu_read_lock_held() &&
447 !rcu_read_lock_bh_held());
448 return (struct dst_entry
*)(skb
->_skb_refdst
& SKB_DST_PTRMASK
);
452 * skb_dst_set - sets skb dst
456 * Sets skb dst, assuming a reference was taken on dst and should
457 * be released by skb_dst_drop()
459 static inline void skb_dst_set(struct sk_buff
*skb
, struct dst_entry
*dst
)
461 skb
->_skb_refdst
= (unsigned long)dst
;
464 extern void skb_dst_set_noref(struct sk_buff
*skb
, struct dst_entry
*dst
);
467 * skb_dst_is_noref - Test if skb dst isnt refcounted
470 static inline bool skb_dst_is_noref(const struct sk_buff
*skb
)
472 return (skb
->_skb_refdst
& SKB_DST_NOREF
) && skb_dst(skb
);
475 static inline struct rtable
*skb_rtable(const struct sk_buff
*skb
)
477 return (struct rtable
*)skb_dst(skb
);
480 extern void kfree_skb(struct sk_buff
*skb
);
481 extern void consume_skb(struct sk_buff
*skb
);
482 extern void __kfree_skb(struct sk_buff
*skb
);
483 extern struct sk_buff
*__alloc_skb(unsigned int size
,
484 gfp_t priority
, int fclone
, int node
);
485 static inline struct sk_buff
*alloc_skb(unsigned int size
,
488 return __alloc_skb(size
, priority
, 0, NUMA_NO_NODE
);
491 static inline struct sk_buff
*alloc_skb_fclone(unsigned int size
,
494 return __alloc_skb(size
, priority
, 1, NUMA_NO_NODE
);
497 extern bool skb_recycle_check(struct sk_buff
*skb
, int skb_size
);
499 extern struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
);
500 extern struct sk_buff
*skb_clone(struct sk_buff
*skb
,
502 extern struct sk_buff
*skb_copy(const struct sk_buff
*skb
,
504 extern struct sk_buff
*pskb_copy(struct sk_buff
*skb
,
506 extern int pskb_expand_head(struct sk_buff
*skb
,
507 int nhead
, int ntail
,
509 extern struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
,
510 unsigned int headroom
);
511 extern struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
512 int newheadroom
, int newtailroom
,
514 extern int skb_to_sgvec(struct sk_buff
*skb
,
515 struct scatterlist
*sg
, int offset
,
517 extern int skb_cow_data(struct sk_buff
*skb
, int tailbits
,
518 struct sk_buff
**trailer
);
519 extern int skb_pad(struct sk_buff
*skb
, int pad
);
520 #define dev_kfree_skb(a) consume_skb(a)
522 extern int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
523 int getfrag(void *from
, char *to
, int offset
,
524 int len
,int odd
, struct sk_buff
*skb
),
525 void *from
, int length
);
527 struct skb_seq_state
{
531 __u32 stepped_offset
;
532 struct sk_buff
*root_skb
;
533 struct sk_buff
*cur_skb
;
537 extern void skb_prepare_seq_read(struct sk_buff
*skb
,
538 unsigned int from
, unsigned int to
,
539 struct skb_seq_state
*st
);
540 extern unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
541 struct skb_seq_state
*st
);
542 extern void skb_abort_seq_read(struct skb_seq_state
*st
);
544 extern unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
545 unsigned int to
, struct ts_config
*config
,
546 struct ts_state
*state
);
548 extern __u32
__skb_get_rxhash(struct sk_buff
*skb
);
549 static inline __u32
skb_get_rxhash(struct sk_buff
*skb
)
552 skb
->rxhash
= __skb_get_rxhash(skb
);
557 #ifdef NET_SKBUFF_DATA_USES_OFFSET
558 static inline unsigned char *skb_end_pointer(const struct sk_buff
*skb
)
560 return skb
->head
+ skb
->end
;
563 static inline unsigned char *skb_end_pointer(const struct sk_buff
*skb
)
570 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
572 static inline struct skb_shared_hwtstamps
*skb_hwtstamps(struct sk_buff
*skb
)
574 return &skb_shinfo(skb
)->hwtstamps
;
578 * skb_queue_empty - check if a queue is empty
581 * Returns true if the queue is empty, false otherwise.
583 static inline int skb_queue_empty(const struct sk_buff_head
*list
)
585 return list
->next
== (struct sk_buff
*)list
;
589 * skb_queue_is_last - check if skb is the last entry in the queue
593 * Returns true if @skb is the last buffer on the list.
595 static inline bool skb_queue_is_last(const struct sk_buff_head
*list
,
596 const struct sk_buff
*skb
)
598 return skb
->next
== (struct sk_buff
*)list
;
602 * skb_queue_is_first - check if skb is the first entry in the queue
606 * Returns true if @skb is the first buffer on the list.
608 static inline bool skb_queue_is_first(const struct sk_buff_head
*list
,
609 const struct sk_buff
*skb
)
611 return skb
->prev
== (struct sk_buff
*)list
;
615 * skb_queue_next - return the next packet in the queue
617 * @skb: current buffer
619 * Return the next packet in @list after @skb. It is only valid to
620 * call this if skb_queue_is_last() evaluates to false.
622 static inline struct sk_buff
*skb_queue_next(const struct sk_buff_head
*list
,
623 const struct sk_buff
*skb
)
625 /* This BUG_ON may seem severe, but if we just return then we
626 * are going to dereference garbage.
628 BUG_ON(skb_queue_is_last(list
, skb
));
633 * skb_queue_prev - return the prev packet in the queue
635 * @skb: current buffer
637 * Return the prev packet in @list before @skb. It is only valid to
638 * call this if skb_queue_is_first() evaluates to false.
640 static inline struct sk_buff
*skb_queue_prev(const struct sk_buff_head
*list
,
641 const struct sk_buff
*skb
)
643 /* This BUG_ON may seem severe, but if we just return then we
644 * are going to dereference garbage.
646 BUG_ON(skb_queue_is_first(list
, skb
));
651 * skb_get - reference buffer
652 * @skb: buffer to reference
654 * Makes another reference to a socket buffer and returns a pointer
657 static inline struct sk_buff
*skb_get(struct sk_buff
*skb
)
659 atomic_inc(&skb
->users
);
664 * If users == 1, we are the only owner and are can avoid redundant
669 * skb_cloned - is the buffer a clone
670 * @skb: buffer to check
672 * Returns true if the buffer was generated with skb_clone() and is
673 * one of multiple shared copies of the buffer. Cloned buffers are
674 * shared data so must not be written to under normal circumstances.
676 static inline int skb_cloned(const struct sk_buff
*skb
)
678 return skb
->cloned
&&
679 (atomic_read(&skb_shinfo(skb
)->dataref
) & SKB_DATAREF_MASK
) != 1;
683 * skb_header_cloned - is the header a clone
684 * @skb: buffer to check
686 * Returns true if modifying the header part of the buffer requires
687 * the data to be copied.
689 static inline int skb_header_cloned(const struct sk_buff
*skb
)
696 dataref
= atomic_read(&skb_shinfo(skb
)->dataref
);
697 dataref
= (dataref
& SKB_DATAREF_MASK
) - (dataref
>> SKB_DATAREF_SHIFT
);
702 * skb_header_release - release reference to header
703 * @skb: buffer to operate on
705 * Drop a reference to the header part of the buffer. This is done
706 * by acquiring a payload reference. You must not read from the header
707 * part of skb->data after this.
709 static inline void skb_header_release(struct sk_buff
*skb
)
713 atomic_add(1 << SKB_DATAREF_SHIFT
, &skb_shinfo(skb
)->dataref
);
717 * skb_shared - is the buffer shared
718 * @skb: buffer to check
720 * Returns true if more than one person has a reference to this
723 static inline int skb_shared(const struct sk_buff
*skb
)
725 return atomic_read(&skb
->users
) != 1;
729 * skb_share_check - check if buffer is shared and if so clone it
730 * @skb: buffer to check
731 * @pri: priority for memory allocation
733 * If the buffer is shared the buffer is cloned and the old copy
734 * drops a reference. A new clone with a single reference is returned.
735 * If the buffer is not shared the original buffer is returned. When
736 * being called from interrupt status or with spinlocks held pri must
739 * NULL is returned on a memory allocation failure.
741 static inline struct sk_buff
*skb_share_check(struct sk_buff
*skb
,
744 might_sleep_if(pri
& __GFP_WAIT
);
745 if (skb_shared(skb
)) {
746 struct sk_buff
*nskb
= skb_clone(skb
, pri
);
754 * Copy shared buffers into a new sk_buff. We effectively do COW on
755 * packets to handle cases where we have a local reader and forward
756 * and a couple of other messy ones. The normal one is tcpdumping
757 * a packet thats being forwarded.
761 * skb_unshare - make a copy of a shared buffer
762 * @skb: buffer to check
763 * @pri: priority for memory allocation
765 * If the socket buffer is a clone then this function creates a new
766 * copy of the data, drops a reference count on the old copy and returns
767 * the new copy with the reference count at 1. If the buffer is not a clone
768 * the original buffer is returned. When called with a spinlock held or
769 * from interrupt state @pri must be %GFP_ATOMIC
771 * %NULL is returned on a memory allocation failure.
773 static inline struct sk_buff
*skb_unshare(struct sk_buff
*skb
,
776 might_sleep_if(pri
& __GFP_WAIT
);
777 if (skb_cloned(skb
)) {
778 struct sk_buff
*nskb
= skb_copy(skb
, pri
);
779 kfree_skb(skb
); /* Free our shared copy */
786 * skb_peek - peek at the head of an &sk_buff_head
787 * @list_: list to peek at
789 * Peek an &sk_buff. Unlike most other operations you _MUST_
790 * be careful with this one. A peek leaves the buffer on the
791 * list and someone else may run off with it. You must hold
792 * the appropriate locks or have a private queue to do this.
794 * Returns %NULL for an empty list or a pointer to the head element.
795 * The reference count is not incremented and the reference is therefore
796 * volatile. Use with caution.
798 static inline struct sk_buff
*skb_peek(struct sk_buff_head
*list_
)
800 struct sk_buff
*list
= ((struct sk_buff
*)list_
)->next
;
801 if (list
== (struct sk_buff
*)list_
)
807 * skb_peek_tail - peek at the tail of an &sk_buff_head
808 * @list_: list to peek at
810 * Peek an &sk_buff. Unlike most other operations you _MUST_
811 * be careful with this one. A peek leaves the buffer on the
812 * list and someone else may run off with it. You must hold
813 * the appropriate locks or have a private queue to do this.
815 * Returns %NULL for an empty list or a pointer to the tail element.
816 * The reference count is not incremented and the reference is therefore
817 * volatile. Use with caution.
819 static inline struct sk_buff
*skb_peek_tail(struct sk_buff_head
*list_
)
821 struct sk_buff
*list
= ((struct sk_buff
*)list_
)->prev
;
822 if (list
== (struct sk_buff
*)list_
)
828 * skb_queue_len - get queue length
829 * @list_: list to measure
831 * Return the length of an &sk_buff queue.
833 static inline __u32
skb_queue_len(const struct sk_buff_head
*list_
)
839 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
840 * @list: queue to initialize
842 * This initializes only the list and queue length aspects of
843 * an sk_buff_head object. This allows to initialize the list
844 * aspects of an sk_buff_head without reinitializing things like
845 * the spinlock. It can also be used for on-stack sk_buff_head
846 * objects where the spinlock is known to not be used.
848 static inline void __skb_queue_head_init(struct sk_buff_head
*list
)
850 list
->prev
= list
->next
= (struct sk_buff
*)list
;
855 * This function creates a split out lock class for each invocation;
856 * this is needed for now since a whole lot of users of the skb-queue
857 * infrastructure in drivers have different locking usage (in hardirq)
858 * than the networking core (in softirq only). In the long run either the
859 * network layer or drivers should need annotation to consolidate the
860 * main types of usage into 3 classes.
862 static inline void skb_queue_head_init(struct sk_buff_head
*list
)
864 spin_lock_init(&list
->lock
);
865 __skb_queue_head_init(list
);
868 static inline void skb_queue_head_init_class(struct sk_buff_head
*list
,
869 struct lock_class_key
*class)
871 skb_queue_head_init(list
);
872 lockdep_set_class(&list
->lock
, class);
876 * Insert an sk_buff on a list.
878 * The "__skb_xxxx()" functions are the non-atomic ones that
879 * can only be called with interrupts disabled.
881 extern void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
);
882 static inline void __skb_insert(struct sk_buff
*newsk
,
883 struct sk_buff
*prev
, struct sk_buff
*next
,
884 struct sk_buff_head
*list
)
888 next
->prev
= prev
->next
= newsk
;
892 static inline void __skb_queue_splice(const struct sk_buff_head
*list
,
893 struct sk_buff
*prev
,
894 struct sk_buff
*next
)
896 struct sk_buff
*first
= list
->next
;
897 struct sk_buff
*last
= list
->prev
;
907 * skb_queue_splice - join two skb lists, this is designed for stacks
908 * @list: the new list to add
909 * @head: the place to add it in the first list
911 static inline void skb_queue_splice(const struct sk_buff_head
*list
,
912 struct sk_buff_head
*head
)
914 if (!skb_queue_empty(list
)) {
915 __skb_queue_splice(list
, (struct sk_buff
*) head
, head
->next
);
916 head
->qlen
+= list
->qlen
;
921 * skb_queue_splice - join two skb lists and reinitialise the emptied list
922 * @list: the new list to add
923 * @head: the place to add it in the first list
925 * The list at @list is reinitialised
927 static inline void skb_queue_splice_init(struct sk_buff_head
*list
,
928 struct sk_buff_head
*head
)
930 if (!skb_queue_empty(list
)) {
931 __skb_queue_splice(list
, (struct sk_buff
*) head
, head
->next
);
932 head
->qlen
+= list
->qlen
;
933 __skb_queue_head_init(list
);
938 * skb_queue_splice_tail - join two skb lists, each list being a queue
939 * @list: the new list to add
940 * @head: the place to add it in the first list
942 static inline void skb_queue_splice_tail(const struct sk_buff_head
*list
,
943 struct sk_buff_head
*head
)
945 if (!skb_queue_empty(list
)) {
946 __skb_queue_splice(list
, head
->prev
, (struct sk_buff
*) head
);
947 head
->qlen
+= list
->qlen
;
952 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
953 * @list: the new list to add
954 * @head: the place to add it in the first list
956 * Each of the lists is a queue.
957 * The list at @list is reinitialised
959 static inline void skb_queue_splice_tail_init(struct sk_buff_head
*list
,
960 struct sk_buff_head
*head
)
962 if (!skb_queue_empty(list
)) {
963 __skb_queue_splice(list
, head
->prev
, (struct sk_buff
*) head
);
964 head
->qlen
+= list
->qlen
;
965 __skb_queue_head_init(list
);
970 * __skb_queue_after - queue a buffer at the list head
972 * @prev: place after this buffer
973 * @newsk: buffer to queue
975 * Queue a buffer int the middle of a list. This function takes no locks
976 * and you must therefore hold required locks before calling it.
978 * A buffer cannot be placed on two lists at the same time.
980 static inline void __skb_queue_after(struct sk_buff_head
*list
,
981 struct sk_buff
*prev
,
982 struct sk_buff
*newsk
)
984 __skb_insert(newsk
, prev
, prev
->next
, list
);
987 extern void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
,
988 struct sk_buff_head
*list
);
990 static inline void __skb_queue_before(struct sk_buff_head
*list
,
991 struct sk_buff
*next
,
992 struct sk_buff
*newsk
)
994 __skb_insert(newsk
, next
->prev
, next
, list
);
998 * __skb_queue_head - queue a buffer at the list head
1000 * @newsk: buffer to queue
1002 * Queue a buffer at the start of a list. This function takes no locks
1003 * and you must therefore hold required locks before calling it.
1005 * A buffer cannot be placed on two lists at the same time.
1007 extern void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
);
1008 static inline void __skb_queue_head(struct sk_buff_head
*list
,
1009 struct sk_buff
*newsk
)
1011 __skb_queue_after(list
, (struct sk_buff
*)list
, newsk
);
1015 * __skb_queue_tail - queue a buffer at the list tail
1016 * @list: list to use
1017 * @newsk: buffer to queue
1019 * Queue a buffer at the end of a list. This function takes no locks
1020 * and you must therefore hold required locks before calling it.
1022 * A buffer cannot be placed on two lists at the same time.
1024 extern void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
);
1025 static inline void __skb_queue_tail(struct sk_buff_head
*list
,
1026 struct sk_buff
*newsk
)
1028 __skb_queue_before(list
, (struct sk_buff
*)list
, newsk
);
1032 * remove sk_buff from list. _Must_ be called atomically, and with
1035 extern void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
);
1036 static inline void __skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
1038 struct sk_buff
*next
, *prev
;
1043 skb
->next
= skb
->prev
= NULL
;
1049 * __skb_dequeue - remove from the head of the queue
1050 * @list: list to dequeue from
1052 * Remove the head of the list. This function does not take any locks
1053 * so must be used with appropriate locks held only. The head item is
1054 * returned or %NULL if the list is empty.
1056 extern struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
);
1057 static inline struct sk_buff
*__skb_dequeue(struct sk_buff_head
*list
)
1059 struct sk_buff
*skb
= skb_peek(list
);
1061 __skb_unlink(skb
, list
);
1066 * __skb_dequeue_tail - remove from the tail of the queue
1067 * @list: list to dequeue from
1069 * Remove the tail of the list. This function does not take any locks
1070 * so must be used with appropriate locks held only. The tail item is
1071 * returned or %NULL if the list is empty.
1073 extern struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
);
1074 static inline struct sk_buff
*__skb_dequeue_tail(struct sk_buff_head
*list
)
1076 struct sk_buff
*skb
= skb_peek_tail(list
);
1078 __skb_unlink(skb
, list
);
1083 static inline int skb_is_nonlinear(const struct sk_buff
*skb
)
1085 return skb
->data_len
;
1088 static inline unsigned int skb_headlen(const struct sk_buff
*skb
)
1090 return skb
->len
- skb
->data_len
;
1093 static inline int skb_pagelen(const struct sk_buff
*skb
)
1097 for (i
= (int)skb_shinfo(skb
)->nr_frags
- 1; i
>= 0; i
--)
1098 len
+= skb_shinfo(skb
)->frags
[i
].size
;
1099 return len
+ skb_headlen(skb
);
1102 static inline void skb_fill_page_desc(struct sk_buff
*skb
, int i
,
1103 struct page
*page
, int off
, int size
)
1105 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1108 frag
->page_offset
= off
;
1110 skb_shinfo(skb
)->nr_frags
= i
+ 1;
1113 extern void skb_add_rx_frag(struct sk_buff
*skb
, int i
, struct page
*page
,
1116 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1117 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1118 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1120 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1121 static inline unsigned char *skb_tail_pointer(const struct sk_buff
*skb
)
1123 return skb
->head
+ skb
->tail
;
1126 static inline void skb_reset_tail_pointer(struct sk_buff
*skb
)
1128 skb
->tail
= skb
->data
- skb
->head
;
1131 static inline void skb_set_tail_pointer(struct sk_buff
*skb
, const int offset
)
1133 skb_reset_tail_pointer(skb
);
1134 skb
->tail
+= offset
;
1136 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1137 static inline unsigned char *skb_tail_pointer(const struct sk_buff
*skb
)
1142 static inline void skb_reset_tail_pointer(struct sk_buff
*skb
)
1144 skb
->tail
= skb
->data
;
1147 static inline void skb_set_tail_pointer(struct sk_buff
*skb
, const int offset
)
1149 skb
->tail
= skb
->data
+ offset
;
1152 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1155 * Add data to an sk_buff
1157 extern unsigned char *skb_put(struct sk_buff
*skb
, unsigned int len
);
1158 static inline unsigned char *__skb_put(struct sk_buff
*skb
, unsigned int len
)
1160 unsigned char *tmp
= skb_tail_pointer(skb
);
1161 SKB_LINEAR_ASSERT(skb
);
1167 extern unsigned char *skb_push(struct sk_buff
*skb
, unsigned int len
);
1168 static inline unsigned char *__skb_push(struct sk_buff
*skb
, unsigned int len
)
1175 extern unsigned char *skb_pull(struct sk_buff
*skb
, unsigned int len
);
1176 static inline unsigned char *__skb_pull(struct sk_buff
*skb
, unsigned int len
)
1179 BUG_ON(skb
->len
< skb
->data_len
);
1180 return skb
->data
+= len
;
1183 static inline unsigned char *skb_pull_inline(struct sk_buff
*skb
, unsigned int len
)
1185 return unlikely(len
> skb
->len
) ? NULL
: __skb_pull(skb
, len
);
1188 extern unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
);
1190 static inline unsigned char *__pskb_pull(struct sk_buff
*skb
, unsigned int len
)
1192 if (len
> skb_headlen(skb
) &&
1193 !__pskb_pull_tail(skb
, len
- skb_headlen(skb
)))
1196 return skb
->data
+= len
;
1199 static inline unsigned char *pskb_pull(struct sk_buff
*skb
, unsigned int len
)
1201 return unlikely(len
> skb
->len
) ? NULL
: __pskb_pull(skb
, len
);
1204 static inline int pskb_may_pull(struct sk_buff
*skb
, unsigned int len
)
1206 if (likely(len
<= skb_headlen(skb
)))
1208 if (unlikely(len
> skb
->len
))
1210 return __pskb_pull_tail(skb
, len
- skb_headlen(skb
)) != NULL
;
1214 * skb_headroom - bytes at buffer head
1215 * @skb: buffer to check
1217 * Return the number of bytes of free space at the head of an &sk_buff.
1219 static inline unsigned int skb_headroom(const struct sk_buff
*skb
)
1221 return skb
->data
- skb
->head
;
1225 * skb_tailroom - bytes at buffer end
1226 * @skb: buffer to check
1228 * Return the number of bytes of free space at the tail of an sk_buff
1230 static inline int skb_tailroom(const struct sk_buff
*skb
)
1232 return skb_is_nonlinear(skb
) ? 0 : skb
->end
- skb
->tail
;
1236 * skb_reserve - adjust headroom
1237 * @skb: buffer to alter
1238 * @len: bytes to move
1240 * Increase the headroom of an empty &sk_buff by reducing the tail
1241 * room. This is only allowed for an empty buffer.
1243 static inline void skb_reserve(struct sk_buff
*skb
, int len
)
1249 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1250 static inline unsigned char *skb_transport_header(const struct sk_buff
*skb
)
1252 return skb
->head
+ skb
->transport_header
;
1255 static inline void skb_reset_transport_header(struct sk_buff
*skb
)
1257 skb
->transport_header
= skb
->data
- skb
->head
;
1260 static inline void skb_set_transport_header(struct sk_buff
*skb
,
1263 skb_reset_transport_header(skb
);
1264 skb
->transport_header
+= offset
;
1267 static inline unsigned char *skb_network_header(const struct sk_buff
*skb
)
1269 return skb
->head
+ skb
->network_header
;
1272 static inline void skb_reset_network_header(struct sk_buff
*skb
)
1274 skb
->network_header
= skb
->data
- skb
->head
;
1277 static inline void skb_set_network_header(struct sk_buff
*skb
, const int offset
)
1279 skb_reset_network_header(skb
);
1280 skb
->network_header
+= offset
;
1283 static inline unsigned char *skb_mac_header(const struct sk_buff
*skb
)
1285 return skb
->head
+ skb
->mac_header
;
1288 static inline int skb_mac_header_was_set(const struct sk_buff
*skb
)
1290 return skb
->mac_header
!= ~0U;
1293 static inline void skb_reset_mac_header(struct sk_buff
*skb
)
1295 skb
->mac_header
= skb
->data
- skb
->head
;
1298 static inline void skb_set_mac_header(struct sk_buff
*skb
, const int offset
)
1300 skb_reset_mac_header(skb
);
1301 skb
->mac_header
+= offset
;
1304 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1306 static inline unsigned char *skb_transport_header(const struct sk_buff
*skb
)
1308 return skb
->transport_header
;
1311 static inline void skb_reset_transport_header(struct sk_buff
*skb
)
1313 skb
->transport_header
= skb
->data
;
1316 static inline void skb_set_transport_header(struct sk_buff
*skb
,
1319 skb
->transport_header
= skb
->data
+ offset
;
1322 static inline unsigned char *skb_network_header(const struct sk_buff
*skb
)
1324 return skb
->network_header
;
1327 static inline void skb_reset_network_header(struct sk_buff
*skb
)
1329 skb
->network_header
= skb
->data
;
1332 static inline void skb_set_network_header(struct sk_buff
*skb
, const int offset
)
1334 skb
->network_header
= skb
->data
+ offset
;
1337 static inline unsigned char *skb_mac_header(const struct sk_buff
*skb
)
1339 return skb
->mac_header
;
1342 static inline int skb_mac_header_was_set(const struct sk_buff
*skb
)
1344 return skb
->mac_header
!= NULL
;
1347 static inline void skb_reset_mac_header(struct sk_buff
*skb
)
1349 skb
->mac_header
= skb
->data
;
1352 static inline void skb_set_mac_header(struct sk_buff
*skb
, const int offset
)
1354 skb
->mac_header
= skb
->data
+ offset
;
1356 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1358 static inline int skb_checksum_start_offset(const struct sk_buff
*skb
)
1360 return skb
->csum_start
- skb_headroom(skb
);
1363 static inline int skb_transport_offset(const struct sk_buff
*skb
)
1365 return skb_transport_header(skb
) - skb
->data
;
1368 static inline u32
skb_network_header_len(const struct sk_buff
*skb
)
1370 return skb
->transport_header
- skb
->network_header
;
1373 static inline int skb_network_offset(const struct sk_buff
*skb
)
1375 return skb_network_header(skb
) - skb
->data
;
1378 static inline int pskb_network_may_pull(struct sk_buff
*skb
, unsigned int len
)
1380 return pskb_may_pull(skb
, skb_network_offset(skb
) + len
);
1384 * CPUs often take a performance hit when accessing unaligned memory
1385 * locations. The actual performance hit varies, it can be small if the
1386 * hardware handles it or large if we have to take an exception and fix it
1389 * Since an ethernet header is 14 bytes network drivers often end up with
1390 * the IP header at an unaligned offset. The IP header can be aligned by
1391 * shifting the start of the packet by 2 bytes. Drivers should do this
1394 * skb_reserve(skb, NET_IP_ALIGN);
1396 * The downside to this alignment of the IP header is that the DMA is now
1397 * unaligned. On some architectures the cost of an unaligned DMA is high
1398 * and this cost outweighs the gains made by aligning the IP header.
1400 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1403 #ifndef NET_IP_ALIGN
1404 #define NET_IP_ALIGN 2
1408 * The networking layer reserves some headroom in skb data (via
1409 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1410 * the header has to grow. In the default case, if the header has to grow
1411 * 32 bytes or less we avoid the reallocation.
1413 * Unfortunately this headroom changes the DMA alignment of the resulting
1414 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1415 * on some architectures. An architecture can override this value,
1416 * perhaps setting it to a cacheline in size (since that will maintain
1417 * cacheline alignment of the DMA). It must be a power of 2.
1419 * Various parts of the networking layer expect at least 32 bytes of
1420 * headroom, you should not reduce this.
1422 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1423 * to reduce average number of cache lines per packet.
1424 * get_rps_cpus() for example only access one 64 bytes aligned block :
1425 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1428 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
1431 extern int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
);
1433 static inline void __skb_trim(struct sk_buff
*skb
, unsigned int len
)
1435 if (unlikely(skb
->data_len
)) {
1440 skb_set_tail_pointer(skb
, len
);
1443 extern void skb_trim(struct sk_buff
*skb
, unsigned int len
);
1445 static inline int __pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1448 return ___pskb_trim(skb
, len
);
1449 __skb_trim(skb
, len
);
1453 static inline int pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1455 return (len
< skb
->len
) ? __pskb_trim(skb
, len
) : 0;
1459 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1460 * @skb: buffer to alter
1463 * This is identical to pskb_trim except that the caller knows that
1464 * the skb is not cloned so we should never get an error due to out-
1467 static inline void pskb_trim_unique(struct sk_buff
*skb
, unsigned int len
)
1469 int err
= pskb_trim(skb
, len
);
1474 * skb_orphan - orphan a buffer
1475 * @skb: buffer to orphan
1477 * If a buffer currently has an owner then we call the owner's
1478 * destructor function and make the @skb unowned. The buffer continues
1479 * to exist but is no longer charged to its former owner.
1481 static inline void skb_orphan(struct sk_buff
*skb
)
1483 if (skb
->destructor
)
1484 skb
->destructor(skb
);
1485 skb
->destructor
= NULL
;
1490 * __skb_queue_purge - empty a list
1491 * @list: list to empty
1493 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1494 * the list and one reference dropped. This function does not take the
1495 * list lock and the caller must hold the relevant locks to use it.
1497 extern void skb_queue_purge(struct sk_buff_head
*list
);
1498 static inline void __skb_queue_purge(struct sk_buff_head
*list
)
1500 struct sk_buff
*skb
;
1501 while ((skb
= __skb_dequeue(list
)) != NULL
)
1506 * __dev_alloc_skb - allocate an skbuff for receiving
1507 * @length: length to allocate
1508 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1510 * Allocate a new &sk_buff and assign it a usage count of one. The
1511 * buffer has unspecified headroom built in. Users should allocate
1512 * the headroom they think they need without accounting for the
1513 * built in space. The built in space is used for optimisations.
1515 * %NULL is returned if there is no free memory.
1517 static inline struct sk_buff
*__dev_alloc_skb(unsigned int length
,
1520 struct sk_buff
*skb
= alloc_skb(length
+ NET_SKB_PAD
, gfp_mask
);
1522 skb_reserve(skb
, NET_SKB_PAD
);
1526 extern struct sk_buff
*dev_alloc_skb(unsigned int length
);
1528 extern struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
,
1529 unsigned int length
, gfp_t gfp_mask
);
1532 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1533 * @dev: network device to receive on
1534 * @length: length to allocate
1536 * Allocate a new &sk_buff and assign it a usage count of one. The
1537 * buffer has unspecified headroom built in. Users should allocate
1538 * the headroom they think they need without accounting for the
1539 * built in space. The built in space is used for optimisations.
1541 * %NULL is returned if there is no free memory. Although this function
1542 * allocates memory it can be called from an interrupt.
1544 static inline struct sk_buff
*netdev_alloc_skb(struct net_device
*dev
,
1545 unsigned int length
)
1547 return __netdev_alloc_skb(dev
, length
, GFP_ATOMIC
);
1550 static inline struct sk_buff
*netdev_alloc_skb_ip_align(struct net_device
*dev
,
1551 unsigned int length
)
1553 struct sk_buff
*skb
= netdev_alloc_skb(dev
, length
+ NET_IP_ALIGN
);
1555 if (NET_IP_ALIGN
&& skb
)
1556 skb_reserve(skb
, NET_IP_ALIGN
);
1561 * __netdev_alloc_page - allocate a page for ps-rx on a specific device
1562 * @dev: network device to receive on
1563 * @gfp_mask: alloc_pages_node mask
1565 * Allocate a new page. dev currently unused.
1567 * %NULL is returned if there is no free memory.
1569 static inline struct page
*__netdev_alloc_page(struct net_device
*dev
, gfp_t gfp_mask
)
1571 return alloc_pages_node(NUMA_NO_NODE
, gfp_mask
, 0);
1575 * netdev_alloc_page - allocate a page for ps-rx on a specific device
1576 * @dev: network device to receive on
1578 * Allocate a new page. dev currently unused.
1580 * %NULL is returned if there is no free memory.
1582 static inline struct page
*netdev_alloc_page(struct net_device
*dev
)
1584 return __netdev_alloc_page(dev
, GFP_ATOMIC
);
1587 static inline void netdev_free_page(struct net_device
*dev
, struct page
*page
)
1593 * skb_clone_writable - is the header of a clone writable
1594 * @skb: buffer to check
1595 * @len: length up to which to write
1597 * Returns true if modifying the header part of the cloned buffer
1598 * does not requires the data to be copied.
1600 static inline int skb_clone_writable(struct sk_buff
*skb
, unsigned int len
)
1602 return !skb_header_cloned(skb
) &&
1603 skb_headroom(skb
) + len
<= skb
->hdr_len
;
1606 static inline int __skb_cow(struct sk_buff
*skb
, unsigned int headroom
,
1611 if (headroom
< NET_SKB_PAD
)
1612 headroom
= NET_SKB_PAD
;
1613 if (headroom
> skb_headroom(skb
))
1614 delta
= headroom
- skb_headroom(skb
);
1616 if (delta
|| cloned
)
1617 return pskb_expand_head(skb
, ALIGN(delta
, NET_SKB_PAD
), 0,
1623 * skb_cow - copy header of skb when it is required
1624 * @skb: buffer to cow
1625 * @headroom: needed headroom
1627 * If the skb passed lacks sufficient headroom or its data part
1628 * is shared, data is reallocated. If reallocation fails, an error
1629 * is returned and original skb is not changed.
1631 * The result is skb with writable area skb->head...skb->tail
1632 * and at least @headroom of space at head.
1634 static inline int skb_cow(struct sk_buff
*skb
, unsigned int headroom
)
1636 return __skb_cow(skb
, headroom
, skb_cloned(skb
));
1640 * skb_cow_head - skb_cow but only making the head writable
1641 * @skb: buffer to cow
1642 * @headroom: needed headroom
1644 * This function is identical to skb_cow except that we replace the
1645 * skb_cloned check by skb_header_cloned. It should be used when
1646 * you only need to push on some header and do not need to modify
1649 static inline int skb_cow_head(struct sk_buff
*skb
, unsigned int headroom
)
1651 return __skb_cow(skb
, headroom
, skb_header_cloned(skb
));
1655 * skb_padto - pad an skbuff up to a minimal size
1656 * @skb: buffer to pad
1657 * @len: minimal length
1659 * Pads up a buffer to ensure the trailing bytes exist and are
1660 * blanked. If the buffer already contains sufficient data it
1661 * is untouched. Otherwise it is extended. Returns zero on
1662 * success. The skb is freed on error.
1665 static inline int skb_padto(struct sk_buff
*skb
, unsigned int len
)
1667 unsigned int size
= skb
->len
;
1668 if (likely(size
>= len
))
1670 return skb_pad(skb
, len
- size
);
1673 static inline int skb_add_data(struct sk_buff
*skb
,
1674 char __user
*from
, int copy
)
1676 const int off
= skb
->len
;
1678 if (skb
->ip_summed
== CHECKSUM_NONE
) {
1680 __wsum csum
= csum_and_copy_from_user(from
, skb_put(skb
, copy
),
1683 skb
->csum
= csum_block_add(skb
->csum
, csum
, off
);
1686 } else if (!copy_from_user(skb_put(skb
, copy
), from
, copy
))
1689 __skb_trim(skb
, off
);
1693 static inline int skb_can_coalesce(struct sk_buff
*skb
, int i
,
1694 struct page
*page
, int off
)
1697 struct skb_frag_struct
*frag
= &skb_shinfo(skb
)->frags
[i
- 1];
1699 return page
== frag
->page
&&
1700 off
== frag
->page_offset
+ frag
->size
;
1705 static inline int __skb_linearize(struct sk_buff
*skb
)
1707 return __pskb_pull_tail(skb
, skb
->data_len
) ? 0 : -ENOMEM
;
1711 * skb_linearize - convert paged skb to linear one
1712 * @skb: buffer to linarize
1714 * If there is no free memory -ENOMEM is returned, otherwise zero
1715 * is returned and the old skb data released.
1717 static inline int skb_linearize(struct sk_buff
*skb
)
1719 return skb_is_nonlinear(skb
) ? __skb_linearize(skb
) : 0;
1723 * skb_linearize_cow - make sure skb is linear and writable
1724 * @skb: buffer to process
1726 * If there is no free memory -ENOMEM is returned, otherwise zero
1727 * is returned and the old skb data released.
1729 static inline int skb_linearize_cow(struct sk_buff
*skb
)
1731 return skb_is_nonlinear(skb
) || skb_cloned(skb
) ?
1732 __skb_linearize(skb
) : 0;
1736 * skb_postpull_rcsum - update checksum for received skb after pull
1737 * @skb: buffer to update
1738 * @start: start of data before pull
1739 * @len: length of data pulled
1741 * After doing a pull on a received packet, you need to call this to
1742 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1743 * CHECKSUM_NONE so that it can be recomputed from scratch.
1746 static inline void skb_postpull_rcsum(struct sk_buff
*skb
,
1747 const void *start
, unsigned int len
)
1749 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
1750 skb
->csum
= csum_sub(skb
->csum
, csum_partial(start
, len
, 0));
1753 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
);
1756 * pskb_trim_rcsum - trim received skb and update checksum
1757 * @skb: buffer to trim
1760 * This is exactly the same as pskb_trim except that it ensures the
1761 * checksum of received packets are still valid after the operation.
1764 static inline int pskb_trim_rcsum(struct sk_buff
*skb
, unsigned int len
)
1766 if (likely(len
>= skb
->len
))
1768 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
1769 skb
->ip_summed
= CHECKSUM_NONE
;
1770 return __pskb_trim(skb
, len
);
1773 #define skb_queue_walk(queue, skb) \
1774 for (skb = (queue)->next; \
1775 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1778 #define skb_queue_walk_safe(queue, skb, tmp) \
1779 for (skb = (queue)->next, tmp = skb->next; \
1780 skb != (struct sk_buff *)(queue); \
1781 skb = tmp, tmp = skb->next)
1783 #define skb_queue_walk_from(queue, skb) \
1784 for (; prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1787 #define skb_queue_walk_from_safe(queue, skb, tmp) \
1788 for (tmp = skb->next; \
1789 skb != (struct sk_buff *)(queue); \
1790 skb = tmp, tmp = skb->next)
1792 #define skb_queue_reverse_walk(queue, skb) \
1793 for (skb = (queue)->prev; \
1794 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1798 static inline bool skb_has_frag_list(const struct sk_buff
*skb
)
1800 return skb_shinfo(skb
)->frag_list
!= NULL
;
1803 static inline void skb_frag_list_init(struct sk_buff
*skb
)
1805 skb_shinfo(skb
)->frag_list
= NULL
;
1808 static inline void skb_frag_add_head(struct sk_buff
*skb
, struct sk_buff
*frag
)
1810 frag
->next
= skb_shinfo(skb
)->frag_list
;
1811 skb_shinfo(skb
)->frag_list
= frag
;
1814 #define skb_walk_frags(skb, iter) \
1815 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
1817 extern struct sk_buff
*__skb_recv_datagram(struct sock
*sk
, unsigned flags
,
1818 int *peeked
, int *err
);
1819 extern struct sk_buff
*skb_recv_datagram(struct sock
*sk
, unsigned flags
,
1820 int noblock
, int *err
);
1821 extern unsigned int datagram_poll(struct file
*file
, struct socket
*sock
,
1822 struct poll_table_struct
*wait
);
1823 extern int skb_copy_datagram_iovec(const struct sk_buff
*from
,
1824 int offset
, struct iovec
*to
,
1826 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff
*skb
,
1829 extern int skb_copy_datagram_from_iovec(struct sk_buff
*skb
,
1831 const struct iovec
*from
,
1834 extern int skb_copy_datagram_const_iovec(const struct sk_buff
*from
,
1836 const struct iovec
*to
,
1839 extern void skb_free_datagram(struct sock
*sk
, struct sk_buff
*skb
);
1840 extern void skb_free_datagram_locked(struct sock
*sk
,
1841 struct sk_buff
*skb
);
1842 extern int skb_kill_datagram(struct sock
*sk
, struct sk_buff
*skb
,
1843 unsigned int flags
);
1844 extern __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
1845 int len
, __wsum csum
);
1846 extern int skb_copy_bits(const struct sk_buff
*skb
, int offset
,
1848 extern int skb_store_bits(struct sk_buff
*skb
, int offset
,
1849 const void *from
, int len
);
1850 extern __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
,
1851 int offset
, u8
*to
, int len
,
1853 extern int skb_splice_bits(struct sk_buff
*skb
,
1854 unsigned int offset
,
1855 struct pipe_inode_info
*pipe
,
1857 unsigned int flags
);
1858 extern void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
);
1859 extern void skb_split(struct sk_buff
*skb
,
1860 struct sk_buff
*skb1
, const u32 len
);
1861 extern int skb_shift(struct sk_buff
*tgt
, struct sk_buff
*skb
,
1864 extern struct sk_buff
*skb_segment(struct sk_buff
*skb
, int features
);
1866 static inline void *skb_header_pointer(const struct sk_buff
*skb
, int offset
,
1867 int len
, void *buffer
)
1869 int hlen
= skb_headlen(skb
);
1871 if (hlen
- offset
>= len
)
1872 return skb
->data
+ offset
;
1874 if (skb_copy_bits(skb
, offset
, buffer
, len
) < 0)
1880 static inline void skb_copy_from_linear_data(const struct sk_buff
*skb
,
1882 const unsigned int len
)
1884 memcpy(to
, skb
->data
, len
);
1887 static inline void skb_copy_from_linear_data_offset(const struct sk_buff
*skb
,
1888 const int offset
, void *to
,
1889 const unsigned int len
)
1891 memcpy(to
, skb
->data
+ offset
, len
);
1894 static inline void skb_copy_to_linear_data(struct sk_buff
*skb
,
1896 const unsigned int len
)
1898 memcpy(skb
->data
, from
, len
);
1901 static inline void skb_copy_to_linear_data_offset(struct sk_buff
*skb
,
1904 const unsigned int len
)
1906 memcpy(skb
->data
+ offset
, from
, len
);
1909 extern void skb_init(void);
1911 static inline ktime_t
skb_get_ktime(const struct sk_buff
*skb
)
1917 * skb_get_timestamp - get timestamp from a skb
1918 * @skb: skb to get stamp from
1919 * @stamp: pointer to struct timeval to store stamp in
1921 * Timestamps are stored in the skb as offsets to a base timestamp.
1922 * This function converts the offset back to a struct timeval and stores
1925 static inline void skb_get_timestamp(const struct sk_buff
*skb
,
1926 struct timeval
*stamp
)
1928 *stamp
= ktime_to_timeval(skb
->tstamp
);
1931 static inline void skb_get_timestampns(const struct sk_buff
*skb
,
1932 struct timespec
*stamp
)
1934 *stamp
= ktime_to_timespec(skb
->tstamp
);
1937 static inline void __net_timestamp(struct sk_buff
*skb
)
1939 skb
->tstamp
= ktime_get_real();
1942 static inline ktime_t
net_timedelta(ktime_t t
)
1944 return ktime_sub(ktime_get_real(), t
);
1947 static inline ktime_t
net_invalid_timestamp(void)
1949 return ktime_set(0, 0);
1952 extern void skb_timestamping_init(void);
1954 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
1956 extern void skb_clone_tx_timestamp(struct sk_buff
*skb
);
1957 extern bool skb_defer_rx_timestamp(struct sk_buff
*skb
);
1959 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
1961 static inline void skb_clone_tx_timestamp(struct sk_buff
*skb
)
1965 static inline bool skb_defer_rx_timestamp(struct sk_buff
*skb
)
1970 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
1973 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
1975 * @skb: clone of the the original outgoing packet
1976 * @hwtstamps: hardware time stamps
1979 void skb_complete_tx_timestamp(struct sk_buff
*skb
,
1980 struct skb_shared_hwtstamps
*hwtstamps
);
1983 * skb_tstamp_tx - queue clone of skb with send time stamps
1984 * @orig_skb: the original outgoing packet
1985 * @hwtstamps: hardware time stamps, may be NULL if not available
1987 * If the skb has a socket associated, then this function clones the
1988 * skb (thus sharing the actual data and optional structures), stores
1989 * the optional hardware time stamping information (if non NULL) or
1990 * generates a software time stamp (otherwise), then queues the clone
1991 * to the error queue of the socket. Errors are silently ignored.
1993 extern void skb_tstamp_tx(struct sk_buff
*orig_skb
,
1994 struct skb_shared_hwtstamps
*hwtstamps
);
1996 static inline void sw_tx_timestamp(struct sk_buff
*skb
)
1998 if (skb_shinfo(skb
)->tx_flags
& SKBTX_SW_TSTAMP
&&
1999 !(skb_shinfo(skb
)->tx_flags
& SKBTX_IN_PROGRESS
))
2000 skb_tstamp_tx(skb
, NULL
);
2004 * skb_tx_timestamp() - Driver hook for transmit timestamping
2006 * Ethernet MAC Drivers should call this function in their hard_xmit()
2007 * function as soon as possible after giving the sk_buff to the MAC
2008 * hardware, but before freeing the sk_buff.
2010 * @skb: A socket buffer.
2012 static inline void skb_tx_timestamp(struct sk_buff
*skb
)
2014 skb_clone_tx_timestamp(skb
);
2015 sw_tx_timestamp(skb
);
2018 extern __sum16
__skb_checksum_complete_head(struct sk_buff
*skb
, int len
);
2019 extern __sum16
__skb_checksum_complete(struct sk_buff
*skb
);
2021 static inline int skb_csum_unnecessary(const struct sk_buff
*skb
)
2023 return skb
->ip_summed
& CHECKSUM_UNNECESSARY
;
2027 * skb_checksum_complete - Calculate checksum of an entire packet
2028 * @skb: packet to process
2030 * This function calculates the checksum over the entire packet plus
2031 * the value of skb->csum. The latter can be used to supply the
2032 * checksum of a pseudo header as used by TCP/UDP. It returns the
2035 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
2036 * this function can be used to verify that checksum on received
2037 * packets. In that case the function should return zero if the
2038 * checksum is correct. In particular, this function will return zero
2039 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2040 * hardware has already verified the correctness of the checksum.
2042 static inline __sum16
skb_checksum_complete(struct sk_buff
*skb
)
2044 return skb_csum_unnecessary(skb
) ?
2045 0 : __skb_checksum_complete(skb
);
2048 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2049 extern void nf_conntrack_destroy(struct nf_conntrack
*nfct
);
2050 static inline void nf_conntrack_put(struct nf_conntrack
*nfct
)
2052 if (nfct
&& atomic_dec_and_test(&nfct
->use
))
2053 nf_conntrack_destroy(nfct
);
2055 static inline void nf_conntrack_get(struct nf_conntrack
*nfct
)
2058 atomic_inc(&nfct
->use
);
2060 static inline void nf_conntrack_get_reasm(struct sk_buff
*skb
)
2063 atomic_inc(&skb
->users
);
2065 static inline void nf_conntrack_put_reasm(struct sk_buff
*skb
)
2071 #ifdef CONFIG_BRIDGE_NETFILTER
2072 static inline void nf_bridge_put(struct nf_bridge_info
*nf_bridge
)
2074 if (nf_bridge
&& atomic_dec_and_test(&nf_bridge
->use
))
2077 static inline void nf_bridge_get(struct nf_bridge_info
*nf_bridge
)
2080 atomic_inc(&nf_bridge
->use
);
2082 #endif /* CONFIG_BRIDGE_NETFILTER */
2083 static inline void nf_reset(struct sk_buff
*skb
)
2085 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2086 nf_conntrack_put(skb
->nfct
);
2088 nf_conntrack_put_reasm(skb
->nfct_reasm
);
2089 skb
->nfct_reasm
= NULL
;
2091 #ifdef CONFIG_BRIDGE_NETFILTER
2092 nf_bridge_put(skb
->nf_bridge
);
2093 skb
->nf_bridge
= NULL
;
2097 /* Note: This doesn't put any conntrack and bridge info in dst. */
2098 static inline void __nf_copy(struct sk_buff
*dst
, const struct sk_buff
*src
)
2100 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2101 dst
->nfct
= src
->nfct
;
2102 nf_conntrack_get(src
->nfct
);
2103 dst
->nfctinfo
= src
->nfctinfo
;
2104 dst
->nfct_reasm
= src
->nfct_reasm
;
2105 nf_conntrack_get_reasm(src
->nfct_reasm
);
2107 #ifdef CONFIG_BRIDGE_NETFILTER
2108 dst
->nf_bridge
= src
->nf_bridge
;
2109 nf_bridge_get(src
->nf_bridge
);
2113 static inline void nf_copy(struct sk_buff
*dst
, const struct sk_buff
*src
)
2115 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2116 nf_conntrack_put(dst
->nfct
);
2117 nf_conntrack_put_reasm(dst
->nfct_reasm
);
2119 #ifdef CONFIG_BRIDGE_NETFILTER
2120 nf_bridge_put(dst
->nf_bridge
);
2122 __nf_copy(dst
, src
);
2125 #ifdef CONFIG_NETWORK_SECMARK
2126 static inline void skb_copy_secmark(struct sk_buff
*to
, const struct sk_buff
*from
)
2128 to
->secmark
= from
->secmark
;
2131 static inline void skb_init_secmark(struct sk_buff
*skb
)
2136 static inline void skb_copy_secmark(struct sk_buff
*to
, const struct sk_buff
*from
)
2139 static inline void skb_init_secmark(struct sk_buff
*skb
)
2143 static inline void skb_set_queue_mapping(struct sk_buff
*skb
, u16 queue_mapping
)
2145 skb
->queue_mapping
= queue_mapping
;
2148 static inline u16
skb_get_queue_mapping(const struct sk_buff
*skb
)
2150 return skb
->queue_mapping
;
2153 static inline void skb_copy_queue_mapping(struct sk_buff
*to
, const struct sk_buff
*from
)
2155 to
->queue_mapping
= from
->queue_mapping
;
2158 static inline void skb_record_rx_queue(struct sk_buff
*skb
, u16 rx_queue
)
2160 skb
->queue_mapping
= rx_queue
+ 1;
2163 static inline u16
skb_get_rx_queue(const struct sk_buff
*skb
)
2165 return skb
->queue_mapping
- 1;
2168 static inline bool skb_rx_queue_recorded(const struct sk_buff
*skb
)
2170 return skb
->queue_mapping
!= 0;
2173 extern u16
__skb_tx_hash(const struct net_device
*dev
,
2174 const struct sk_buff
*skb
,
2175 unsigned int num_tx_queues
);
2178 static inline struct sec_path
*skb_sec_path(struct sk_buff
*skb
)
2183 static inline struct sec_path
*skb_sec_path(struct sk_buff
*skb
)
2189 static inline int skb_is_gso(const struct sk_buff
*skb
)
2191 return skb_shinfo(skb
)->gso_size
;
2194 static inline int skb_is_gso_v6(const struct sk_buff
*skb
)
2196 return skb_shinfo(skb
)->gso_type
& SKB_GSO_TCPV6
;
2199 extern void __skb_warn_lro_forwarding(const struct sk_buff
*skb
);
2201 static inline bool skb_warn_if_lro(const struct sk_buff
*skb
)
2203 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2204 * wanted then gso_type will be set. */
2205 struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
2206 if (skb_is_nonlinear(skb
) && shinfo
->gso_size
!= 0 &&
2207 unlikely(shinfo
->gso_type
== 0)) {
2208 __skb_warn_lro_forwarding(skb
);
2214 static inline void skb_forward_csum(struct sk_buff
*skb
)
2216 /* Unfortunately we don't support this one. Any brave souls? */
2217 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
2218 skb
->ip_summed
= CHECKSUM_NONE
;
2222 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2223 * @skb: skb to check
2225 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2226 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2227 * use this helper, to document places where we make this assertion.
2229 static inline void skb_checksum_none_assert(struct sk_buff
*skb
)
2232 BUG_ON(skb
->ip_summed
!= CHECKSUM_NONE
);
2236 bool skb_partial_csum_set(struct sk_buff
*skb
, u16 start
, u16 off
);
2237 #endif /* __KERNEL__ */
2238 #endif /* _LINUX_SKBUFF_H */