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/bug.h>
22 #include <linux/cache.h>
24 #include <linux/atomic.h>
25 #include <asm/types.h>
26 #include <linux/spinlock.h>
27 #include <linux/net.h>
28 #include <linux/textsearch.h>
29 #include <net/checksum.h>
30 #include <linux/rcupdate.h>
31 #include <linux/dmaengine.h>
32 #include <linux/hrtimer.h>
33 #include <linux/dma-mapping.h>
34 #include <linux/netdev_features.h>
36 /* Don't change this without changing skb_csum_unnecessary! */
37 #define CHECKSUM_NONE 0
38 #define CHECKSUM_UNNECESSARY 1
39 #define CHECKSUM_COMPLETE 2
40 #define CHECKSUM_PARTIAL 3
42 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
43 ~(SMP_CACHE_BYTES - 1))
44 #define SKB_WITH_OVERHEAD(X) \
45 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
46 #define SKB_MAX_ORDER(X, ORDER) \
47 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
48 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
49 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
51 /* return minimum truesize of one skb containing X bytes of data */
52 #define SKB_TRUESIZE(X) ((X) + \
53 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
54 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
56 /* A. Checksumming of received packets by device.
58 * NONE: device failed to checksum this packet.
59 * skb->csum is undefined.
61 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
62 * skb->csum is undefined.
63 * It is bad option, but, unfortunately, many of vendors do this.
64 * Apparently with secret goal to sell you new device, when you
65 * will add new protocol to your host. F.e. IPv6. 8)
67 * COMPLETE: the most generic way. Device supplied checksum of _all_
68 * the packet as seen by netif_rx in skb->csum.
69 * NOTE: Even if device supports only some protocols, but
70 * is able to produce some skb->csum, it MUST use COMPLETE,
73 * PARTIAL: identical to the case for output below. This may occur
74 * on a packet received directly from another Linux OS, e.g.,
75 * a virtualised Linux kernel on the same host. The packet can
76 * be treated in the same way as UNNECESSARY except that on
77 * output (i.e., forwarding) the checksum must be filled in
78 * by the OS or the hardware.
80 * B. Checksumming on output.
82 * NONE: skb is checksummed by protocol or csum is not required.
84 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
85 * from skb->csum_start to the end and to record the checksum
86 * at skb->csum_start + skb->csum_offset.
88 * Device must show its capabilities in dev->features, set
89 * at device setup time.
90 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
92 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
93 * TCP/UDP over IPv4. Sigh. Vendors like this
94 * way by an unknown reason. Though, see comment above
95 * about CHECKSUM_UNNECESSARY. 8)
96 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
98 * UNNECESSARY: device will do per protocol specific csum. Protocol drivers
99 * that do not want net to perform the checksum calculation should use
100 * this flag in their outgoing skbs.
101 * NETIF_F_FCOE_CRC this indicates the device can do FCoE FC CRC
102 * offload. Correspondingly, the FCoE protocol driver
103 * stack should use CHECKSUM_UNNECESSARY.
105 * Any questions? No questions, good. --ANK
110 struct pipe_inode_info;
112 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
113 struct nf_conntrack {
118 #ifdef CONFIG_BRIDGE_NETFILTER
119 struct nf_bridge_info {
122 struct net_device *physindev;
123 struct net_device *physoutdev;
124 unsigned long data[32 / sizeof(unsigned long)];
128 struct sk_buff_head {
129 /* These two members must be first. */
130 struct sk_buff *next;
131 struct sk_buff *prev;
139 /* To allow 64K frame to be packed as single skb without frag_list we
140 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
141 * buffers which do not start on a page boundary.
143 * Since GRO uses frags we allocate at least 16 regardless of page
146 #if (65536/PAGE_SIZE + 1) < 16
147 #define MAX_SKB_FRAGS 16UL
149 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
152 typedef struct skb_frag_struct skb_frag_t;
154 struct skb_frag_struct {
158 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
167 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
172 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
177 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
182 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
187 #define HAVE_HW_TIME_STAMP
190 * struct skb_shared_hwtstamps - hardware time stamps
191 * @hwtstamp: hardware time stamp transformed into duration
192 * since arbitrary point in time
193 * @syststamp: hwtstamp transformed to system time base
195 * Software time stamps generated by ktime_get_real() are stored in
196 * skb->tstamp. The relation between the different kinds of time
197 * stamps is as follows:
199 * syststamp and tstamp can be compared against each other in
200 * arbitrary combinations. The accuracy of a
201 * syststamp/tstamp/"syststamp from other device" comparison is
202 * limited by the accuracy of the transformation into system time
203 * base. This depends on the device driver and its underlying
206 * hwtstamps can only be compared against other hwtstamps from
209 * This structure is attached to packets as part of the
210 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
212 struct skb_shared_hwtstamps {
217 /* Definitions for tx_flags in struct skb_shared_info */
219 /* generate hardware time stamp */
220 SKBTX_HW_TSTAMP = 1 << 0,
222 /* generate software time stamp */
223 SKBTX_SW_TSTAMP = 1 << 1,
225 /* device driver is going to provide hardware time stamp */
226 SKBTX_IN_PROGRESS = 1 << 2,
228 /* device driver supports TX zero-copy buffers */
229 SKBTX_DEV_ZEROCOPY = 1 << 3,
231 /* generate wifi status information (where possible) */
232 SKBTX_WIFI_STATUS = 1 << 4,
234 /* This indicates at least one fragment might be overwritten
235 * (as in vmsplice(), sendfile() ...)
236 * If we need to compute a TX checksum, we'll need to copy
237 * all frags to avoid possible bad checksum
239 SKBTX_SHARED_FRAG = 1 << 5,
243 * The callback notifies userspace to release buffers when skb DMA is done in
244 * lower device, the skb last reference should be 0 when calling this.
245 * The zerocopy_success argument is true if zero copy transmit occurred,
246 * false on data copy or out of memory error caused by data copy attempt.
247 * The ctx field is used to track device context.
248 * The desc field is used to track userspace buffer index.
251 void (*callback)(struct ubuf_info *, bool zerocopy_success);
256 /* This data is invariant across clones and lives at
257 * the end of the header data, ie. at skb->end.
259 struct skb_shared_info {
260 unsigned char nr_frags;
262 unsigned short gso_size;
263 /* Warning: this field is not always filled in (UFO)! */
264 unsigned short gso_segs;
265 unsigned short gso_type;
266 struct sk_buff *frag_list;
267 struct skb_shared_hwtstamps hwtstamps;
271 * Warning : all fields before dataref are cleared in __alloc_skb()
275 /* Intermediate layers must ensure that destructor_arg
276 * remains valid until skb destructor */
277 void * destructor_arg;
279 /* must be last field, see pskb_expand_head() */
280 skb_frag_t frags[MAX_SKB_FRAGS];
283 /* We divide dataref into two halves. The higher 16 bits hold references
284 * to the payload part of skb->data. The lower 16 bits hold references to
285 * the entire skb->data. A clone of a headerless skb holds the length of
286 * the header in skb->hdr_len.
288 * All users must obey the rule that the skb->data reference count must be
289 * greater than or equal to the payload reference count.
291 * Holding a reference to the payload part means that the user does not
292 * care about modifications to the header part of skb->data.
294 #define SKB_DATAREF_SHIFT 16
295 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
299 SKB_FCLONE_UNAVAILABLE,
305 SKB_GSO_TCPV4 = 1 << 0,
306 SKB_GSO_UDP = 1 << 1,
308 /* This indicates the skb is from an untrusted source. */
309 SKB_GSO_DODGY = 1 << 2,
311 /* This indicates the tcp segment has CWR set. */
312 SKB_GSO_TCP_ECN = 1 << 3,
314 SKB_GSO_TCPV6 = 1 << 4,
316 SKB_GSO_FCOE = 1 << 5,
319 #if BITS_PER_LONG > 32
320 #define NET_SKBUFF_DATA_USES_OFFSET 1
323 #ifdef NET_SKBUFF_DATA_USES_OFFSET
324 typedef unsigned int sk_buff_data_t;
326 typedef unsigned char *sk_buff_data_t;
329 #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
330 defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
331 #define NET_SKBUFF_NF_DEFRAG_NEEDED 1
335 * struct sk_buff - socket buffer
336 * @next: Next buffer in list
337 * @prev: Previous buffer in list
338 * @tstamp: Time we arrived
339 * @sk: Socket we are owned by
340 * @dev: Device we arrived on/are leaving by
341 * @cb: Control buffer. Free for use by every layer. Put private vars here
342 * @_skb_refdst: destination entry (with norefcount bit)
343 * @sp: the security path, used for xfrm
344 * @len: Length of actual data
345 * @data_len: Data length
346 * @mac_len: Length of link layer header
347 * @hdr_len: writable header length of cloned skb
348 * @csum: Checksum (must include start/offset pair)
349 * @csum_start: Offset from skb->head where checksumming should start
350 * @csum_offset: Offset from csum_start where checksum should be stored
351 * @priority: Packet queueing priority
352 * @local_df: allow local fragmentation
353 * @cloned: Head may be cloned (check refcnt to be sure)
354 * @ip_summed: Driver fed us an IP checksum
355 * @nohdr: Payload reference only, must not modify header
356 * @nfctinfo: Relationship of this skb to the connection
357 * @pkt_type: Packet class
358 * @fclone: skbuff clone status
359 * @ipvs_property: skbuff is owned by ipvs
360 * @peeked: this packet has been seen already, so stats have been
361 * done for it, don't do them again
362 * @nf_trace: netfilter packet trace flag
363 * @protocol: Packet protocol from driver
364 * @destructor: Destruct function
365 * @nfct: Associated connection, if any
366 * @nfct_reasm: netfilter conntrack re-assembly pointer
367 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
368 * @skb_iif: ifindex of device we arrived on
369 * @tc_index: Traffic control index
370 * @tc_verd: traffic control verdict
371 * @rxhash: the packet hash computed on receive
372 * @queue_mapping: Queue mapping for multiqueue devices
373 * @ndisc_nodetype: router type (from link layer)
374 * @ooo_okay: allow the mapping of a socket to a queue to be changed
375 * @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
377 * @wifi_acked_valid: wifi_acked was set
378 * @wifi_acked: whether frame was acked on wifi or not
379 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
380 * @dma_cookie: a cookie to one of several possible DMA operations
381 * done by skb DMA functions
382 * @secmark: security marking
383 * @mark: Generic packet mark
384 * @dropcount: total number of sk_receive_queue overflows
385 * @vlan_tci: vlan tag control information
386 * @inner_transport_header: Inner transport layer header (encapsulation)
387 * @inner_network_header: Network layer header (encapsulation)
388 * @transport_header: Transport layer header
389 * @network_header: Network layer header
390 * @mac_header: Link layer header
391 * @tail: Tail pointer
393 * @head: Head of buffer
394 * @data: Data head pointer
395 * @truesize: Buffer size
396 * @users: User count - see {datagram,tcp}.c
400 /* These two members must be first. */
401 struct sk_buff *next;
402 struct sk_buff *prev;
407 struct net_device *dev;
410 * This is the control buffer. It is free to use for every
411 * layer. Please put your private variables there. If you
412 * want to keep them across layers you have to do a skb_clone()
413 * first. This is owned by whoever has the skb queued ATM.
415 char cb[48] __aligned(8);
417 unsigned long _skb_refdst;
433 kmemcheck_bitfield_begin(flags1);
444 kmemcheck_bitfield_end(flags1);
447 void (*destructor)(struct sk_buff *skb);
448 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
449 struct nf_conntrack *nfct;
451 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
452 struct sk_buff *nfct_reasm;
454 #ifdef CONFIG_BRIDGE_NETFILTER
455 struct nf_bridge_info *nf_bridge;
464 #ifdef CONFIG_NET_SCHED
465 __u16 tc_index; /* traffic control index */
466 #ifdef CONFIG_NET_CLS_ACT
467 __u16 tc_verd; /* traffic control verdict */
472 kmemcheck_bitfield_begin(flags2);
473 #ifdef CONFIG_IPV6_NDISC_NODETYPE
474 __u8 ndisc_nodetype:2;
479 __u8 wifi_acked_valid:1;
483 /* Encapsulation protocol and NIC drivers should use
484 * this flag to indicate to each other if the skb contains
485 * encapsulated packet or not and maybe use the inner packet
488 __u8 encapsulation:1;
489 /* 7/9 bit hole (depending on ndisc_nodetype presence) */
490 kmemcheck_bitfield_end(flags2);
492 #ifdef CONFIG_NET_DMA
493 dma_cookie_t dma_cookie;
495 #ifdef CONFIG_NETWORK_SECMARK
504 sk_buff_data_t inner_transport_header;
505 sk_buff_data_t inner_network_header;
506 sk_buff_data_t transport_header;
507 sk_buff_data_t network_header;
508 sk_buff_data_t mac_header;
509 /* These elements must be at the end, see alloc_skb() for details. */
514 unsigned int truesize;
520 * Handling routines are only of interest to the kernel
522 #include <linux/slab.h>
525 #define SKB_ALLOC_FCLONE 0x01
526 #define SKB_ALLOC_RX 0x02
528 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
529 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
531 return unlikely(skb->pfmemalloc);
535 * skb might have a dst pointer attached, refcounted or not.
536 * _skb_refdst low order bit is set if refcount was _not_ taken
538 #define SKB_DST_NOREF 1UL
539 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
542 * skb_dst - returns skb dst_entry
545 * Returns skb dst_entry, regardless of reference taken or not.
547 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
549 /* If refdst was not refcounted, check we still are in a
550 * rcu_read_lock section
552 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
553 !rcu_read_lock_held() &&
554 !rcu_read_lock_bh_held());
555 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
559 * skb_dst_set - sets skb dst
563 * Sets skb dst, assuming a reference was taken on dst and should
564 * be released by skb_dst_drop()
566 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
568 skb->_skb_refdst = (unsigned long)dst;
571 extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);
574 * skb_dst_is_noref - Test if skb dst isn't refcounted
577 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
579 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
582 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
584 return (struct rtable *)skb_dst(skb);
587 extern void kfree_skb(struct sk_buff *skb);
588 extern void skb_tx_error(struct sk_buff *skb);
589 extern void consume_skb(struct sk_buff *skb);
590 extern void __kfree_skb(struct sk_buff *skb);
591 extern struct kmem_cache *skbuff_head_cache;
593 extern void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
594 extern bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
595 bool *fragstolen, int *delta_truesize);
597 extern struct sk_buff *__alloc_skb(unsigned int size,
598 gfp_t priority, int flags, int node);
599 extern struct sk_buff *build_skb(void *data, unsigned int frag_size);
600 static inline struct sk_buff *alloc_skb(unsigned int size,
603 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
606 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
609 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
612 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
613 extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
614 extern struct sk_buff *skb_clone(struct sk_buff *skb,
616 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
618 extern struct sk_buff *__pskb_copy(struct sk_buff *skb,
619 int headroom, gfp_t gfp_mask);
621 extern int pskb_expand_head(struct sk_buff *skb,
622 int nhead, int ntail,
624 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
625 unsigned int headroom);
626 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
627 int newheadroom, int newtailroom,
629 extern int skb_to_sgvec(struct sk_buff *skb,
630 struct scatterlist *sg, int offset,
632 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
633 struct sk_buff **trailer);
634 extern int skb_pad(struct sk_buff *skb, int pad);
635 #define dev_kfree_skb(a) consume_skb(a)
637 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
638 int getfrag(void *from, char *to, int offset,
639 int len,int odd, struct sk_buff *skb),
640 void *from, int length);
642 struct skb_seq_state {
646 __u32 stepped_offset;
647 struct sk_buff *root_skb;
648 struct sk_buff *cur_skb;
652 extern void skb_prepare_seq_read(struct sk_buff *skb,
653 unsigned int from, unsigned int to,
654 struct skb_seq_state *st);
655 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
656 struct skb_seq_state *st);
657 extern void skb_abort_seq_read(struct skb_seq_state *st);
659 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
660 unsigned int to, struct ts_config *config,
661 struct ts_state *state);
663 extern void __skb_get_rxhash(struct sk_buff *skb);
664 static inline __u32 skb_get_rxhash(struct sk_buff *skb)
667 __skb_get_rxhash(skb);
672 #ifdef NET_SKBUFF_DATA_USES_OFFSET
673 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
675 return skb->head + skb->end;
678 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
683 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
688 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
690 return skb->end - skb->head;
695 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
697 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
699 return &skb_shinfo(skb)->hwtstamps;
703 * skb_queue_empty - check if a queue is empty
706 * Returns true if the queue is empty, false otherwise.
708 static inline int skb_queue_empty(const struct sk_buff_head *list)
710 return list->next == (struct sk_buff *)list;
714 * skb_queue_is_last - check if skb is the last entry in the queue
718 * Returns true if @skb is the last buffer on the list.
720 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
721 const struct sk_buff *skb)
723 return skb->next == (struct sk_buff *)list;
727 * skb_queue_is_first - check if skb is the first entry in the queue
731 * Returns true if @skb is the first buffer on the list.
733 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
734 const struct sk_buff *skb)
736 return skb->prev == (struct sk_buff *)list;
740 * skb_queue_next - return the next packet in the queue
742 * @skb: current buffer
744 * Return the next packet in @list after @skb. It is only valid to
745 * call this if skb_queue_is_last() evaluates to false.
747 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
748 const struct sk_buff *skb)
750 /* This BUG_ON may seem severe, but if we just return then we
751 * are going to dereference garbage.
753 BUG_ON(skb_queue_is_last(list, skb));
758 * skb_queue_prev - return the prev packet in the queue
760 * @skb: current buffer
762 * Return the prev packet in @list before @skb. It is only valid to
763 * call this if skb_queue_is_first() evaluates to false.
765 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
766 const struct sk_buff *skb)
768 /* This BUG_ON may seem severe, but if we just return then we
769 * are going to dereference garbage.
771 BUG_ON(skb_queue_is_first(list, skb));
776 * skb_get - reference buffer
777 * @skb: buffer to reference
779 * Makes another reference to a socket buffer and returns a pointer
782 static inline struct sk_buff *skb_get(struct sk_buff *skb)
784 atomic_inc(&skb->users);
789 * If users == 1, we are the only owner and are can avoid redundant
794 * skb_cloned - is the buffer a clone
795 * @skb: buffer to check
797 * Returns true if the buffer was generated with skb_clone() and is
798 * one of multiple shared copies of the buffer. Cloned buffers are
799 * shared data so must not be written to under normal circumstances.
801 static inline int skb_cloned(const struct sk_buff *skb)
803 return skb->cloned &&
804 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
807 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
809 might_sleep_if(pri & __GFP_WAIT);
812 return pskb_expand_head(skb, 0, 0, pri);
818 * skb_header_cloned - is the header a clone
819 * @skb: buffer to check
821 * Returns true if modifying the header part of the buffer requires
822 * the data to be copied.
824 static inline int skb_header_cloned(const struct sk_buff *skb)
831 dataref = atomic_read(&skb_shinfo(skb)->dataref);
832 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
837 * skb_header_release - release reference to header
838 * @skb: buffer to operate on
840 * Drop a reference to the header part of the buffer. This is done
841 * by acquiring a payload reference. You must not read from the header
842 * part of skb->data after this.
844 static inline void skb_header_release(struct sk_buff *skb)
848 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
852 * skb_shared - is the buffer shared
853 * @skb: buffer to check
855 * Returns true if more than one person has a reference to this
858 static inline int skb_shared(const struct sk_buff *skb)
860 return atomic_read(&skb->users) != 1;
864 * skb_share_check - check if buffer is shared and if so clone it
865 * @skb: buffer to check
866 * @pri: priority for memory allocation
868 * If the buffer is shared the buffer is cloned and the old copy
869 * drops a reference. A new clone with a single reference is returned.
870 * If the buffer is not shared the original buffer is returned. When
871 * being called from interrupt status or with spinlocks held pri must
874 * NULL is returned on a memory allocation failure.
876 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
878 might_sleep_if(pri & __GFP_WAIT);
879 if (skb_shared(skb)) {
880 struct sk_buff *nskb = skb_clone(skb, pri);
892 * Copy shared buffers into a new sk_buff. We effectively do COW on
893 * packets to handle cases where we have a local reader and forward
894 * and a couple of other messy ones. The normal one is tcpdumping
895 * a packet thats being forwarded.
899 * skb_unshare - make a copy of a shared buffer
900 * @skb: buffer to check
901 * @pri: priority for memory allocation
903 * If the socket buffer is a clone then this function creates a new
904 * copy of the data, drops a reference count on the old copy and returns
905 * the new copy with the reference count at 1. If the buffer is not a clone
906 * the original buffer is returned. When called with a spinlock held or
907 * from interrupt state @pri must be %GFP_ATOMIC
909 * %NULL is returned on a memory allocation failure.
911 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
914 might_sleep_if(pri & __GFP_WAIT);
915 if (skb_cloned(skb)) {
916 struct sk_buff *nskb = skb_copy(skb, pri);
917 kfree_skb(skb); /* Free our shared copy */
924 * skb_peek - peek at the head of an &sk_buff_head
925 * @list_: list to peek at
927 * Peek an &sk_buff. Unlike most other operations you _MUST_
928 * be careful with this one. A peek leaves the buffer on the
929 * list and someone else may run off with it. You must hold
930 * the appropriate locks or have a private queue to do this.
932 * Returns %NULL for an empty list or a pointer to the head element.
933 * The reference count is not incremented and the reference is therefore
934 * volatile. Use with caution.
936 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
938 struct sk_buff *skb = list_->next;
940 if (skb == (struct sk_buff *)list_)
946 * skb_peek_next - peek skb following the given one from a queue
947 * @skb: skb to start from
948 * @list_: list to peek at
950 * Returns %NULL when the end of the list is met or a pointer to the
951 * next element. The reference count is not incremented and the
952 * reference is therefore volatile. Use with caution.
954 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
955 const struct sk_buff_head *list_)
957 struct sk_buff *next = skb->next;
959 if (next == (struct sk_buff *)list_)
965 * skb_peek_tail - peek at the tail of an &sk_buff_head
966 * @list_: list to peek at
968 * Peek an &sk_buff. Unlike most other operations you _MUST_
969 * be careful with this one. A peek leaves the buffer on the
970 * list and someone else may run off with it. You must hold
971 * the appropriate locks or have a private queue to do this.
973 * Returns %NULL for an empty list or a pointer to the tail element.
974 * The reference count is not incremented and the reference is therefore
975 * volatile. Use with caution.
977 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
979 struct sk_buff *skb = list_->prev;
981 if (skb == (struct sk_buff *)list_)
988 * skb_queue_len - get queue length
989 * @list_: list to measure
991 * Return the length of an &sk_buff queue.
993 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
999 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1000 * @list: queue to initialize
1002 * This initializes only the list and queue length aspects of
1003 * an sk_buff_head object. This allows to initialize the list
1004 * aspects of an sk_buff_head without reinitializing things like
1005 * the spinlock. It can also be used for on-stack sk_buff_head
1006 * objects where the spinlock is known to not be used.
1008 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1010 list->prev = list->next = (struct sk_buff *)list;
1015 * This function creates a split out lock class for each invocation;
1016 * this is needed for now since a whole lot of users of the skb-queue
1017 * infrastructure in drivers have different locking usage (in hardirq)
1018 * than the networking core (in softirq only). In the long run either the
1019 * network layer or drivers should need annotation to consolidate the
1020 * main types of usage into 3 classes.
1022 static inline void skb_queue_head_init(struct sk_buff_head *list)
1024 spin_lock_init(&list->lock);
1025 __skb_queue_head_init(list);
1028 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1029 struct lock_class_key *class)
1031 skb_queue_head_init(list);
1032 lockdep_set_class(&list->lock, class);
1036 * Insert an sk_buff on a list.
1038 * The "__skb_xxxx()" functions are the non-atomic ones that
1039 * can only be called with interrupts disabled.
1041 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
1042 static inline void __skb_insert(struct sk_buff *newsk,
1043 struct sk_buff *prev, struct sk_buff *next,
1044 struct sk_buff_head *list)
1048 next->prev = prev->next = newsk;
1052 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1053 struct sk_buff *prev,
1054 struct sk_buff *next)
1056 struct sk_buff *first = list->next;
1057 struct sk_buff *last = list->prev;
1067 * skb_queue_splice - join two skb lists, this is designed for stacks
1068 * @list: the new list to add
1069 * @head: the place to add it in the first list
1071 static inline void skb_queue_splice(const struct sk_buff_head *list,
1072 struct sk_buff_head *head)
1074 if (!skb_queue_empty(list)) {
1075 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1076 head->qlen += list->qlen;
1081 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1082 * @list: the new list to add
1083 * @head: the place to add it in the first list
1085 * The list at @list is reinitialised
1087 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1088 struct sk_buff_head *head)
1090 if (!skb_queue_empty(list)) {
1091 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1092 head->qlen += list->qlen;
1093 __skb_queue_head_init(list);
1098 * skb_queue_splice_tail - join two skb lists, each list being a queue
1099 * @list: the new list to add
1100 * @head: the place to add it in the first list
1102 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1103 struct sk_buff_head *head)
1105 if (!skb_queue_empty(list)) {
1106 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1107 head->qlen += list->qlen;
1112 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1113 * @list: the new list to add
1114 * @head: the place to add it in the first list
1116 * Each of the lists is a queue.
1117 * The list at @list is reinitialised
1119 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1120 struct sk_buff_head *head)
1122 if (!skb_queue_empty(list)) {
1123 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1124 head->qlen += list->qlen;
1125 __skb_queue_head_init(list);
1130 * __skb_queue_after - queue a buffer at the list head
1131 * @list: list to use
1132 * @prev: place after this buffer
1133 * @newsk: buffer to queue
1135 * Queue a buffer int the middle of a list. This function takes no locks
1136 * and you must therefore hold required locks before calling it.
1138 * A buffer cannot be placed on two lists at the same time.
1140 static inline void __skb_queue_after(struct sk_buff_head *list,
1141 struct sk_buff *prev,
1142 struct sk_buff *newsk)
1144 __skb_insert(newsk, prev, prev->next, list);
1147 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1148 struct sk_buff_head *list);
1150 static inline void __skb_queue_before(struct sk_buff_head *list,
1151 struct sk_buff *next,
1152 struct sk_buff *newsk)
1154 __skb_insert(newsk, next->prev, next, list);
1158 * __skb_queue_head - queue a buffer at the list head
1159 * @list: list to use
1160 * @newsk: buffer to queue
1162 * Queue a buffer at the start of a list. This function takes no locks
1163 * and you must therefore hold required locks before calling it.
1165 * A buffer cannot be placed on two lists at the same time.
1167 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1168 static inline void __skb_queue_head(struct sk_buff_head *list,
1169 struct sk_buff *newsk)
1171 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1175 * __skb_queue_tail - queue a buffer at the list tail
1176 * @list: list to use
1177 * @newsk: buffer to queue
1179 * Queue a buffer at the end of a list. This function takes no locks
1180 * and you must therefore hold required locks before calling it.
1182 * A buffer cannot be placed on two lists at the same time.
1184 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1185 static inline void __skb_queue_tail(struct sk_buff_head *list,
1186 struct sk_buff *newsk)
1188 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1192 * remove sk_buff from list. _Must_ be called atomically, and with
1195 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1196 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1198 struct sk_buff *next, *prev;
1203 skb->next = skb->prev = NULL;
1209 * __skb_dequeue - remove from the head of the queue
1210 * @list: list to dequeue from
1212 * Remove the head of the list. This function does not take any locks
1213 * so must be used with appropriate locks held only. The head item is
1214 * returned or %NULL if the list is empty.
1216 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1217 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1219 struct sk_buff *skb = skb_peek(list);
1221 __skb_unlink(skb, list);
1226 * __skb_dequeue_tail - remove from the tail of the queue
1227 * @list: list to dequeue from
1229 * Remove the tail of the list. This function does not take any locks
1230 * so must be used with appropriate locks held only. The tail item is
1231 * returned or %NULL if the list is empty.
1233 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1234 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1236 struct sk_buff *skb = skb_peek_tail(list);
1238 __skb_unlink(skb, list);
1243 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1245 return skb->data_len;
1248 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1250 return skb->len - skb->data_len;
1253 static inline int skb_pagelen(const struct sk_buff *skb)
1257 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1258 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1259 return len + skb_headlen(skb);
1263 * __skb_fill_page_desc - initialise a paged fragment in an skb
1264 * @skb: buffer containing fragment to be initialised
1265 * @i: paged fragment index to initialise
1266 * @page: the page to use for this fragment
1267 * @off: the offset to the data with @page
1268 * @size: the length of the data
1270 * Initialises the @i'th fragment of @skb to point to &size bytes at
1271 * offset @off within @page.
1273 * Does not take any additional reference on the fragment.
1275 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1276 struct page *page, int off, int size)
1278 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1281 * Propagate page->pfmemalloc to the skb if we can. The problem is
1282 * that not all callers have unique ownership of the page. If
1283 * pfmemalloc is set, we check the mapping as a mapping implies
1284 * page->index is set (index and pfmemalloc share space).
1285 * If it's a valid mapping, we cannot use page->pfmemalloc but we
1286 * do not lose pfmemalloc information as the pages would not be
1287 * allocated using __GFP_MEMALLOC.
1289 if (page->pfmemalloc && !page->mapping)
1290 skb->pfmemalloc = true;
1291 frag->page.p = page;
1292 frag->page_offset = off;
1293 skb_frag_size_set(frag, size);
1297 * skb_fill_page_desc - initialise a paged fragment in an skb
1298 * @skb: buffer containing fragment to be initialised
1299 * @i: paged fragment index to initialise
1300 * @page: the page to use for this fragment
1301 * @off: the offset to the data with @page
1302 * @size: the length of the data
1304 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1305 * @skb to point to &size bytes at offset @off within @page. In
1306 * addition updates @skb such that @i is the last fragment.
1308 * Does not take any additional reference on the fragment.
1310 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1311 struct page *page, int off, int size)
1313 __skb_fill_page_desc(skb, i, page, off, size);
1314 skb_shinfo(skb)->nr_frags = i + 1;
1317 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1318 int off, int size, unsigned int truesize);
1320 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1321 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1322 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1324 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1325 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1327 return skb->head + skb->tail;
1330 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1332 skb->tail = skb->data - skb->head;
1335 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1337 skb_reset_tail_pointer(skb);
1338 skb->tail += offset;
1340 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1341 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1346 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1348 skb->tail = skb->data;
1351 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1353 skb->tail = skb->data + offset;
1356 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1359 * Add data to an sk_buff
1361 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1362 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1364 unsigned char *tmp = skb_tail_pointer(skb);
1365 SKB_LINEAR_ASSERT(skb);
1371 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1372 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1379 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1380 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1383 BUG_ON(skb->len < skb->data_len);
1384 return skb->data += len;
1387 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1389 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1392 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1394 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1396 if (len > skb_headlen(skb) &&
1397 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1400 return skb->data += len;
1403 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1405 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1408 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1410 if (likely(len <= skb_headlen(skb)))
1412 if (unlikely(len > skb->len))
1414 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1418 * skb_headroom - bytes at buffer head
1419 * @skb: buffer to check
1421 * Return the number of bytes of free space at the head of an &sk_buff.
1423 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1425 return skb->data - skb->head;
1429 * skb_tailroom - bytes at buffer end
1430 * @skb: buffer to check
1432 * Return the number of bytes of free space at the tail of an sk_buff
1434 static inline int skb_tailroom(const struct sk_buff *skb)
1436 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1440 * skb_availroom - bytes at buffer end
1441 * @skb: buffer to check
1443 * Return the number of bytes of free space at the tail of an sk_buff
1444 * allocated by sk_stream_alloc()
1446 static inline int skb_availroom(const struct sk_buff *skb)
1448 return skb_is_nonlinear(skb) ? 0 : skb->avail_size - skb->len;
1452 * skb_reserve - adjust headroom
1453 * @skb: buffer to alter
1454 * @len: bytes to move
1456 * Increase the headroom of an empty &sk_buff by reducing the tail
1457 * room. This is only allowed for an empty buffer.
1459 static inline void skb_reserve(struct sk_buff *skb, int len)
1465 static inline void skb_reset_inner_headers(struct sk_buff *skb)
1467 skb->inner_network_header = skb->network_header;
1468 skb->inner_transport_header = skb->transport_header;
1471 static inline void skb_reset_mac_len(struct sk_buff *skb)
1473 skb->mac_len = skb->network_header - skb->mac_header;
1476 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1477 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
1480 return skb->head + skb->inner_transport_header;
1483 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
1485 skb->inner_transport_header = skb->data - skb->head;
1488 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
1491 skb_reset_inner_transport_header(skb);
1492 skb->inner_transport_header += offset;
1495 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
1497 return skb->head + skb->inner_network_header;
1500 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
1502 skb->inner_network_header = skb->data - skb->head;
1505 static inline void skb_set_inner_network_header(struct sk_buff *skb,
1508 skb_reset_inner_network_header(skb);
1509 skb->inner_network_header += offset;
1512 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
1514 return skb->transport_header != ~0U;
1517 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1519 return skb->head + skb->transport_header;
1522 static inline void skb_reset_transport_header(struct sk_buff *skb)
1524 skb->transport_header = skb->data - skb->head;
1527 static inline void skb_set_transport_header(struct sk_buff *skb,
1530 skb_reset_transport_header(skb);
1531 skb->transport_header += offset;
1534 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1536 return skb->head + skb->network_header;
1539 static inline void skb_reset_network_header(struct sk_buff *skb)
1541 skb->network_header = skb->data - skb->head;
1544 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1546 skb_reset_network_header(skb);
1547 skb->network_header += offset;
1550 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1552 return skb->head + skb->mac_header;
1555 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1557 return skb->mac_header != ~0U;
1560 static inline void skb_reset_mac_header(struct sk_buff *skb)
1562 skb->mac_header = skb->data - skb->head;
1565 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1567 skb_reset_mac_header(skb);
1568 skb->mac_header += offset;
1571 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1572 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
1575 return skb->inner_transport_header;
1578 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
1580 skb->inner_transport_header = skb->data;
1583 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
1586 skb->inner_transport_header = skb->data + offset;
1589 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
1591 return skb->inner_network_header;
1594 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
1596 skb->inner_network_header = skb->data;
1599 static inline void skb_set_inner_network_header(struct sk_buff *skb,
1602 skb->inner_network_header = skb->data + offset;
1605 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
1607 return skb->transport_header != NULL;
1610 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1612 return skb->transport_header;
1615 static inline void skb_reset_transport_header(struct sk_buff *skb)
1617 skb->transport_header = skb->data;
1620 static inline void skb_set_transport_header(struct sk_buff *skb,
1623 skb->transport_header = skb->data + offset;
1626 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1628 return skb->network_header;
1631 static inline void skb_reset_network_header(struct sk_buff *skb)
1633 skb->network_header = skb->data;
1636 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1638 skb->network_header = skb->data + offset;
1641 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1643 return skb->mac_header;
1646 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1648 return skb->mac_header != NULL;
1651 static inline void skb_reset_mac_header(struct sk_buff *skb)
1653 skb->mac_header = skb->data;
1656 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1658 skb->mac_header = skb->data + offset;
1660 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1662 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
1664 if (skb_mac_header_was_set(skb)) {
1665 const unsigned char *old_mac = skb_mac_header(skb);
1667 skb_set_mac_header(skb, -skb->mac_len);
1668 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
1672 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1674 return skb->csum_start - skb_headroom(skb);
1677 static inline int skb_transport_offset(const struct sk_buff *skb)
1679 return skb_transport_header(skb) - skb->data;
1682 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1684 return skb->transport_header - skb->network_header;
1687 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
1689 return skb->inner_transport_header - skb->inner_network_header;
1692 static inline int skb_network_offset(const struct sk_buff *skb)
1694 return skb_network_header(skb) - skb->data;
1697 static inline int skb_inner_network_offset(const struct sk_buff *skb)
1699 return skb_inner_network_header(skb) - skb->data;
1702 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1704 return pskb_may_pull(skb, skb_network_offset(skb) + len);
1708 * CPUs often take a performance hit when accessing unaligned memory
1709 * locations. The actual performance hit varies, it can be small if the
1710 * hardware handles it or large if we have to take an exception and fix it
1713 * Since an ethernet header is 14 bytes network drivers often end up with
1714 * the IP header at an unaligned offset. The IP header can be aligned by
1715 * shifting the start of the packet by 2 bytes. Drivers should do this
1718 * skb_reserve(skb, NET_IP_ALIGN);
1720 * The downside to this alignment of the IP header is that the DMA is now
1721 * unaligned. On some architectures the cost of an unaligned DMA is high
1722 * and this cost outweighs the gains made by aligning the IP header.
1724 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1727 #ifndef NET_IP_ALIGN
1728 #define NET_IP_ALIGN 2
1732 * The networking layer reserves some headroom in skb data (via
1733 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1734 * the header has to grow. In the default case, if the header has to grow
1735 * 32 bytes or less we avoid the reallocation.
1737 * Unfortunately this headroom changes the DMA alignment of the resulting
1738 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1739 * on some architectures. An architecture can override this value,
1740 * perhaps setting it to a cacheline in size (since that will maintain
1741 * cacheline alignment of the DMA). It must be a power of 2.
1743 * Various parts of the networking layer expect at least 32 bytes of
1744 * headroom, you should not reduce this.
1746 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1747 * to reduce average number of cache lines per packet.
1748 * get_rps_cpus() for example only access one 64 bytes aligned block :
1749 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1752 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
1755 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1757 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1759 if (unlikely(skb_is_nonlinear(skb))) {
1764 skb_set_tail_pointer(skb, len);
1767 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1769 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1772 return ___pskb_trim(skb, len);
1773 __skb_trim(skb, len);
1777 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1779 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1783 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1784 * @skb: buffer to alter
1787 * This is identical to pskb_trim except that the caller knows that
1788 * the skb is not cloned so we should never get an error due to out-
1791 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1793 int err = pskb_trim(skb, len);
1798 * skb_orphan - orphan a buffer
1799 * @skb: buffer to orphan
1801 * If a buffer currently has an owner then we call the owner's
1802 * destructor function and make the @skb unowned. The buffer continues
1803 * to exist but is no longer charged to its former owner.
1805 static inline void skb_orphan(struct sk_buff *skb)
1807 if (skb->destructor)
1808 skb->destructor(skb);
1809 skb->destructor = NULL;
1814 * skb_orphan_frags - orphan the frags contained in a buffer
1815 * @skb: buffer to orphan frags from
1816 * @gfp_mask: allocation mask for replacement pages
1818 * For each frag in the SKB which needs a destructor (i.e. has an
1819 * owner) create a copy of that frag and release the original
1820 * page by calling the destructor.
1822 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
1824 if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
1826 return skb_copy_ubufs(skb, gfp_mask);
1830 * __skb_queue_purge - empty a list
1831 * @list: list to empty
1833 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1834 * the list and one reference dropped. This function does not take the
1835 * list lock and the caller must hold the relevant locks to use it.
1837 extern void skb_queue_purge(struct sk_buff_head *list);
1838 static inline void __skb_queue_purge(struct sk_buff_head *list)
1840 struct sk_buff *skb;
1841 while ((skb = __skb_dequeue(list)) != NULL)
1845 #define NETDEV_FRAG_PAGE_MAX_ORDER get_order(32768)
1846 #define NETDEV_FRAG_PAGE_MAX_SIZE (PAGE_SIZE << NETDEV_FRAG_PAGE_MAX_ORDER)
1847 #define NETDEV_PAGECNT_MAX_BIAS NETDEV_FRAG_PAGE_MAX_SIZE
1849 extern void *netdev_alloc_frag(unsigned int fragsz);
1851 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1852 unsigned int length,
1856 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1857 * @dev: network device to receive on
1858 * @length: length to allocate
1860 * Allocate a new &sk_buff and assign it a usage count of one. The
1861 * buffer has unspecified headroom built in. Users should allocate
1862 * the headroom they think they need without accounting for the
1863 * built in space. The built in space is used for optimisations.
1865 * %NULL is returned if there is no free memory. Although this function
1866 * allocates memory it can be called from an interrupt.
1868 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1869 unsigned int length)
1871 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1874 /* legacy helper around __netdev_alloc_skb() */
1875 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1878 return __netdev_alloc_skb(NULL, length, gfp_mask);
1881 /* legacy helper around netdev_alloc_skb() */
1882 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1884 return netdev_alloc_skb(NULL, length);
1888 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1889 unsigned int length, gfp_t gfp)
1891 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1893 if (NET_IP_ALIGN && skb)
1894 skb_reserve(skb, NET_IP_ALIGN);
1898 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1899 unsigned int length)
1901 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1905 * __skb_alloc_page - allocate pages for ps-rx on a skb and preserve pfmemalloc data
1906 * @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1907 * @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1908 * @order: size of the allocation
1910 * Allocate a new page.
1912 * %NULL is returned if there is no free memory.
1914 static inline struct page *__skb_alloc_pages(gfp_t gfp_mask,
1915 struct sk_buff *skb,
1920 gfp_mask |= __GFP_COLD;
1922 if (!(gfp_mask & __GFP_NOMEMALLOC))
1923 gfp_mask |= __GFP_MEMALLOC;
1925 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
1926 if (skb && page && page->pfmemalloc)
1927 skb->pfmemalloc = true;
1933 * __skb_alloc_page - allocate a page for ps-rx for a given skb and preserve pfmemalloc data
1934 * @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1935 * @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1937 * Allocate a new page.
1939 * %NULL is returned if there is no free memory.
1941 static inline struct page *__skb_alloc_page(gfp_t gfp_mask,
1942 struct sk_buff *skb)
1944 return __skb_alloc_pages(gfp_mask, skb, 0);
1948 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
1949 * @page: The page that was allocated from skb_alloc_page
1950 * @skb: The skb that may need pfmemalloc set
1952 static inline void skb_propagate_pfmemalloc(struct page *page,
1953 struct sk_buff *skb)
1955 if (page && page->pfmemalloc)
1956 skb->pfmemalloc = true;
1960 * skb_frag_page - retrieve the page refered to by a paged fragment
1961 * @frag: the paged fragment
1963 * Returns the &struct page associated with @frag.
1965 static inline struct page *skb_frag_page(const skb_frag_t *frag)
1967 return frag->page.p;
1971 * __skb_frag_ref - take an addition reference on a paged fragment.
1972 * @frag: the paged fragment
1974 * Takes an additional reference on the paged fragment @frag.
1976 static inline void __skb_frag_ref(skb_frag_t *frag)
1978 get_page(skb_frag_page(frag));
1982 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
1984 * @f: the fragment offset.
1986 * Takes an additional reference on the @f'th paged fragment of @skb.
1988 static inline void skb_frag_ref(struct sk_buff *skb, int f)
1990 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
1994 * __skb_frag_unref - release a reference on a paged fragment.
1995 * @frag: the paged fragment
1997 * Releases a reference on the paged fragment @frag.
1999 static inline void __skb_frag_unref(skb_frag_t *frag)
2001 put_page(skb_frag_page(frag));
2005 * skb_frag_unref - release a reference on a paged fragment of an skb.
2007 * @f: the fragment offset
2009 * Releases a reference on the @f'th paged fragment of @skb.
2011 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2013 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2017 * skb_frag_address - gets the address of the data contained in a paged fragment
2018 * @frag: the paged fragment buffer
2020 * Returns the address of the data within @frag. The page must already
2023 static inline void *skb_frag_address(const skb_frag_t *frag)
2025 return page_address(skb_frag_page(frag)) + frag->page_offset;
2029 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2030 * @frag: the paged fragment buffer
2032 * Returns the address of the data within @frag. Checks that the page
2033 * is mapped and returns %NULL otherwise.
2035 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2037 void *ptr = page_address(skb_frag_page(frag));
2041 return ptr + frag->page_offset;
2045 * __skb_frag_set_page - sets the page contained in a paged fragment
2046 * @frag: the paged fragment
2047 * @page: the page to set
2049 * Sets the fragment @frag to contain @page.
2051 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2053 frag->page.p = page;
2057 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2059 * @f: the fragment offset
2060 * @page: the page to set
2062 * Sets the @f'th fragment of @skb to contain @page.
2064 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2067 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2071 * skb_frag_dma_map - maps a paged fragment via the DMA API
2072 * @dev: the device to map the fragment to
2073 * @frag: the paged fragment to map
2074 * @offset: the offset within the fragment (starting at the
2075 * fragment's own offset)
2076 * @size: the number of bytes to map
2077 * @dir: the direction of the mapping (%PCI_DMA_*)
2079 * Maps the page associated with @frag to @device.
2081 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2082 const skb_frag_t *frag,
2083 size_t offset, size_t size,
2084 enum dma_data_direction dir)
2086 return dma_map_page(dev, skb_frag_page(frag),
2087 frag->page_offset + offset, size, dir);
2090 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2093 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2097 * skb_clone_writable - is the header of a clone writable
2098 * @skb: buffer to check
2099 * @len: length up to which to write
2101 * Returns true if modifying the header part of the cloned buffer
2102 * does not requires the data to be copied.
2104 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2106 return !skb_header_cloned(skb) &&
2107 skb_headroom(skb) + len <= skb->hdr_len;
2110 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2115 if (headroom > skb_headroom(skb))
2116 delta = headroom - skb_headroom(skb);
2118 if (delta || cloned)
2119 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2125 * skb_cow - copy header of skb when it is required
2126 * @skb: buffer to cow
2127 * @headroom: needed headroom
2129 * If the skb passed lacks sufficient headroom or its data part
2130 * is shared, data is reallocated. If reallocation fails, an error
2131 * is returned and original skb is not changed.
2133 * The result is skb with writable area skb->head...skb->tail
2134 * and at least @headroom of space at head.
2136 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2138 return __skb_cow(skb, headroom, skb_cloned(skb));
2142 * skb_cow_head - skb_cow but only making the head writable
2143 * @skb: buffer to cow
2144 * @headroom: needed headroom
2146 * This function is identical to skb_cow except that we replace the
2147 * skb_cloned check by skb_header_cloned. It should be used when
2148 * you only need to push on some header and do not need to modify
2151 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2153 return __skb_cow(skb, headroom, skb_header_cloned(skb));
2157 * skb_padto - pad an skbuff up to a minimal size
2158 * @skb: buffer to pad
2159 * @len: minimal length
2161 * Pads up a buffer to ensure the trailing bytes exist and are
2162 * blanked. If the buffer already contains sufficient data it
2163 * is untouched. Otherwise it is extended. Returns zero on
2164 * success. The skb is freed on error.
2167 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2169 unsigned int size = skb->len;
2170 if (likely(size >= len))
2172 return skb_pad(skb, len - size);
2175 static inline int skb_add_data(struct sk_buff *skb,
2176 char __user *from, int copy)
2178 const int off = skb->len;
2180 if (skb->ip_summed == CHECKSUM_NONE) {
2182 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
2185 skb->csum = csum_block_add(skb->csum, csum, off);
2188 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
2191 __skb_trim(skb, off);
2195 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2196 const struct page *page, int off)
2199 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2201 return page == skb_frag_page(frag) &&
2202 off == frag->page_offset + skb_frag_size(frag);
2207 static inline int __skb_linearize(struct sk_buff *skb)
2209 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2213 * skb_linearize - convert paged skb to linear one
2214 * @skb: buffer to linarize
2216 * If there is no free memory -ENOMEM is returned, otherwise zero
2217 * is returned and the old skb data released.
2219 static inline int skb_linearize(struct sk_buff *skb)
2221 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2225 * skb_has_shared_frag - can any frag be overwritten
2226 * @skb: buffer to test
2228 * Return true if the skb has at least one frag that might be modified
2229 * by an external entity (as in vmsplice()/sendfile())
2231 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2233 return skb_is_nonlinear(skb) &&
2234 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2238 * skb_linearize_cow - make sure skb is linear and writable
2239 * @skb: buffer to process
2241 * If there is no free memory -ENOMEM is returned, otherwise zero
2242 * is returned and the old skb data released.
2244 static inline int skb_linearize_cow(struct sk_buff *skb)
2246 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2247 __skb_linearize(skb) : 0;
2251 * skb_postpull_rcsum - update checksum for received skb after pull
2252 * @skb: buffer to update
2253 * @start: start of data before pull
2254 * @len: length of data pulled
2256 * After doing a pull on a received packet, you need to call this to
2257 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2258 * CHECKSUM_NONE so that it can be recomputed from scratch.
2261 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2262 const void *start, unsigned int len)
2264 if (skb->ip_summed == CHECKSUM_COMPLETE)
2265 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
2268 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2271 * pskb_trim_rcsum - trim received skb and update checksum
2272 * @skb: buffer to trim
2275 * This is exactly the same as pskb_trim except that it ensures the
2276 * checksum of received packets are still valid after the operation.
2279 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2281 if (likely(len >= skb->len))
2283 if (skb->ip_summed == CHECKSUM_COMPLETE)
2284 skb->ip_summed = CHECKSUM_NONE;
2285 return __pskb_trim(skb, len);
2288 #define skb_queue_walk(queue, skb) \
2289 for (skb = (queue)->next; \
2290 skb != (struct sk_buff *)(queue); \
2293 #define skb_queue_walk_safe(queue, skb, tmp) \
2294 for (skb = (queue)->next, tmp = skb->next; \
2295 skb != (struct sk_buff *)(queue); \
2296 skb = tmp, tmp = skb->next)
2298 #define skb_queue_walk_from(queue, skb) \
2299 for (; skb != (struct sk_buff *)(queue); \
2302 #define skb_queue_walk_from_safe(queue, skb, tmp) \
2303 for (tmp = skb->next; \
2304 skb != (struct sk_buff *)(queue); \
2305 skb = tmp, tmp = skb->next)
2307 #define skb_queue_reverse_walk(queue, skb) \
2308 for (skb = (queue)->prev; \
2309 skb != (struct sk_buff *)(queue); \
2312 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
2313 for (skb = (queue)->prev, tmp = skb->prev; \
2314 skb != (struct sk_buff *)(queue); \
2315 skb = tmp, tmp = skb->prev)
2317 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
2318 for (tmp = skb->prev; \
2319 skb != (struct sk_buff *)(queue); \
2320 skb = tmp, tmp = skb->prev)
2322 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2324 return skb_shinfo(skb)->frag_list != NULL;
2327 static inline void skb_frag_list_init(struct sk_buff *skb)
2329 skb_shinfo(skb)->frag_list = NULL;
2332 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2334 frag->next = skb_shinfo(skb)->frag_list;
2335 skb_shinfo(skb)->frag_list = frag;
2338 #define skb_walk_frags(skb, iter) \
2339 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2341 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2342 int *peeked, int *off, int *err);
2343 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
2344 int noblock, int *err);
2345 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
2346 struct poll_table_struct *wait);
2347 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
2348 int offset, struct iovec *to,
2350 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
2353 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
2355 const struct iovec *from,
2358 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
2360 const struct iovec *to,
2363 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2364 extern void skb_free_datagram_locked(struct sock *sk,
2365 struct sk_buff *skb);
2366 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
2367 unsigned int flags);
2368 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
2369 int len, __wsum csum);
2370 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
2372 extern int skb_store_bits(struct sk_buff *skb, int offset,
2373 const void *from, int len);
2374 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
2375 int offset, u8 *to, int len,
2377 extern int skb_splice_bits(struct sk_buff *skb,
2378 unsigned int offset,
2379 struct pipe_inode_info *pipe,
2381 unsigned int flags);
2382 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2383 extern void skb_split(struct sk_buff *skb,
2384 struct sk_buff *skb1, const u32 len);
2385 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
2388 extern struct sk_buff *skb_segment(struct sk_buff *skb,
2389 netdev_features_t features);
2391 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2392 int len, void *buffer)
2394 int hlen = skb_headlen(skb);
2396 if (hlen - offset >= len)
2397 return skb->data + offset;
2399 if (skb_copy_bits(skb, offset, buffer, len) < 0)
2405 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2407 const unsigned int len)
2409 memcpy(to, skb->data, len);
2412 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2413 const int offset, void *to,
2414 const unsigned int len)
2416 memcpy(to, skb->data + offset, len);
2419 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2421 const unsigned int len)
2423 memcpy(skb->data, from, len);
2426 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2429 const unsigned int len)
2431 memcpy(skb->data + offset, from, len);
2434 extern void skb_init(void);
2436 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2442 * skb_get_timestamp - get timestamp from a skb
2443 * @skb: skb to get stamp from
2444 * @stamp: pointer to struct timeval to store stamp in
2446 * Timestamps are stored in the skb as offsets to a base timestamp.
2447 * This function converts the offset back to a struct timeval and stores
2450 static inline void skb_get_timestamp(const struct sk_buff *skb,
2451 struct timeval *stamp)
2453 *stamp = ktime_to_timeval(skb->tstamp);
2456 static inline void skb_get_timestampns(const struct sk_buff *skb,
2457 struct timespec *stamp)
2459 *stamp = ktime_to_timespec(skb->tstamp);
2462 static inline void __net_timestamp(struct sk_buff *skb)
2464 skb->tstamp = ktime_get_real();
2467 static inline ktime_t net_timedelta(ktime_t t)
2469 return ktime_sub(ktime_get_real(), t);
2472 static inline ktime_t net_invalid_timestamp(void)
2474 return ktime_set(0, 0);
2477 extern void skb_timestamping_init(void);
2479 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2481 extern void skb_clone_tx_timestamp(struct sk_buff *skb);
2482 extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
2484 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2486 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2490 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2495 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2498 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2500 * PHY drivers may accept clones of transmitted packets for
2501 * timestamping via their phy_driver.txtstamp method. These drivers
2502 * must call this function to return the skb back to the stack, with
2503 * or without a timestamp.
2505 * @skb: clone of the the original outgoing packet
2506 * @hwtstamps: hardware time stamps, may be NULL if not available
2509 void skb_complete_tx_timestamp(struct sk_buff *skb,
2510 struct skb_shared_hwtstamps *hwtstamps);
2513 * skb_tstamp_tx - queue clone of skb with send time stamps
2514 * @orig_skb: the original outgoing packet
2515 * @hwtstamps: hardware time stamps, may be NULL if not available
2517 * If the skb has a socket associated, then this function clones the
2518 * skb (thus sharing the actual data and optional structures), stores
2519 * the optional hardware time stamping information (if non NULL) or
2520 * generates a software time stamp (otherwise), then queues the clone
2521 * to the error queue of the socket. Errors are silently ignored.
2523 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
2524 struct skb_shared_hwtstamps *hwtstamps);
2526 static inline void sw_tx_timestamp(struct sk_buff *skb)
2528 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2529 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2530 skb_tstamp_tx(skb, NULL);
2534 * skb_tx_timestamp() - Driver hook for transmit timestamping
2536 * Ethernet MAC Drivers should call this function in their hard_xmit()
2537 * function immediately before giving the sk_buff to the MAC hardware.
2539 * @skb: A socket buffer.
2541 static inline void skb_tx_timestamp(struct sk_buff *skb)
2543 skb_clone_tx_timestamp(skb);
2544 sw_tx_timestamp(skb);
2548 * skb_complete_wifi_ack - deliver skb with wifi status
2550 * @skb: the original outgoing packet
2551 * @acked: ack status
2554 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
2556 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2557 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
2559 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2561 return skb->ip_summed & CHECKSUM_UNNECESSARY;
2565 * skb_checksum_complete - Calculate checksum of an entire packet
2566 * @skb: packet to process
2568 * This function calculates the checksum over the entire packet plus
2569 * the value of skb->csum. The latter can be used to supply the
2570 * checksum of a pseudo header as used by TCP/UDP. It returns the
2573 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
2574 * this function can be used to verify that checksum on received
2575 * packets. In that case the function should return zero if the
2576 * checksum is correct. In particular, this function will return zero
2577 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2578 * hardware has already verified the correctness of the checksum.
2580 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2582 return skb_csum_unnecessary(skb) ?
2583 0 : __skb_checksum_complete(skb);
2586 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2587 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
2588 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2590 if (nfct && atomic_dec_and_test(&nfct->use))
2591 nf_conntrack_destroy(nfct);
2593 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2596 atomic_inc(&nfct->use);
2599 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2600 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
2603 atomic_inc(&skb->users);
2605 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
2611 #ifdef CONFIG_BRIDGE_NETFILTER
2612 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2614 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2617 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2620 atomic_inc(&nf_bridge->use);
2622 #endif /* CONFIG_BRIDGE_NETFILTER */
2623 static inline void nf_reset(struct sk_buff *skb)
2625 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2626 nf_conntrack_put(skb->nfct);
2629 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2630 nf_conntrack_put_reasm(skb->nfct_reasm);
2631 skb->nfct_reasm = NULL;
2633 #ifdef CONFIG_BRIDGE_NETFILTER
2634 nf_bridge_put(skb->nf_bridge);
2635 skb->nf_bridge = NULL;
2639 /* Note: This doesn't put any conntrack and bridge info in dst. */
2640 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2642 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2643 dst->nfct = src->nfct;
2644 nf_conntrack_get(src->nfct);
2645 dst->nfctinfo = src->nfctinfo;
2647 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2648 dst->nfct_reasm = src->nfct_reasm;
2649 nf_conntrack_get_reasm(src->nfct_reasm);
2651 #ifdef CONFIG_BRIDGE_NETFILTER
2652 dst->nf_bridge = src->nf_bridge;
2653 nf_bridge_get(src->nf_bridge);
2657 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2659 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2660 nf_conntrack_put(dst->nfct);
2662 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2663 nf_conntrack_put_reasm(dst->nfct_reasm);
2665 #ifdef CONFIG_BRIDGE_NETFILTER
2666 nf_bridge_put(dst->nf_bridge);
2668 __nf_copy(dst, src);
2671 #ifdef CONFIG_NETWORK_SECMARK
2672 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2674 to->secmark = from->secmark;
2677 static inline void skb_init_secmark(struct sk_buff *skb)
2682 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2685 static inline void skb_init_secmark(struct sk_buff *skb)
2689 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2691 skb->queue_mapping = queue_mapping;
2694 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2696 return skb->queue_mapping;
2699 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2701 to->queue_mapping = from->queue_mapping;
2704 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2706 skb->queue_mapping = rx_queue + 1;
2709 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2711 return skb->queue_mapping - 1;
2714 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2716 return skb->queue_mapping != 0;
2719 extern u16 __skb_tx_hash(const struct net_device *dev,
2720 const struct sk_buff *skb,
2721 unsigned int num_tx_queues);
2724 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2729 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2735 static inline bool skb_is_gso(const struct sk_buff *skb)
2737 return skb_shinfo(skb)->gso_size;
2740 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
2742 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2745 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2747 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2749 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2750 * wanted then gso_type will be set. */
2751 const struct skb_shared_info *shinfo = skb_shinfo(skb);
2753 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2754 unlikely(shinfo->gso_type == 0)) {
2755 __skb_warn_lro_forwarding(skb);
2761 static inline void skb_forward_csum(struct sk_buff *skb)
2763 /* Unfortunately we don't support this one. Any brave souls? */
2764 if (skb->ip_summed == CHECKSUM_COMPLETE)
2765 skb->ip_summed = CHECKSUM_NONE;
2769 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2770 * @skb: skb to check
2772 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2773 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2774 * use this helper, to document places where we make this assertion.
2776 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2779 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2783 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2786 * skb_head_is_locked - Determine if the skb->head is locked down
2787 * @skb: skb to check
2789 * The head on skbs build around a head frag can be removed if they are
2790 * not cloned. This function returns true if the skb head is locked down
2791 * due to either being allocated via kmalloc, or by being a clone with
2792 * multiple references to the head.
2794 static inline bool skb_head_is_locked(const struct sk_buff *skb)
2796 return !skb->head_frag || skb_cloned(skb);
2798 #endif /* __KERNEL__ */
2799 #endif /* _LINUX_SKBUFF_H */