2 * Definitions for the 'struct sk_buff' memory handlers.
5 * Alan Cox, <gw4pts@gw4pts.ampr.org>
6 * Florian La Roche, <rzsfl@rz.uni-sb.de>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
17 #include <linux/kernel.h>
18 #include <linux/compiler.h>
19 #include <linux/time.h>
20 #include <linux/bug.h>
21 #include <linux/cache.h>
22 #include <linux/rbtree.h>
23 #include <linux/socket.h>
24 #include <linux/refcount.h>
26 #include <linux/atomic.h>
27 #include <asm/types.h>
28 #include <linux/spinlock.h>
29 #include <linux/net.h>
30 #include <linux/textsearch.h>
31 #include <net/checksum.h>
32 #include <linux/rcupdate.h>
33 #include <linux/hrtimer.h>
34 #include <linux/dma-mapping.h>
35 #include <linux/netdev_features.h>
36 #include <linux/sched.h>
37 #include <linux/sched/clock.h>
38 #include <net/flow_dissector.h>
39 #include <linux/splice.h>
40 #include <linux/in6.h>
41 #include <linux/if_packet.h>
44 /* The interface for checksum offload between the stack and networking drivers
47 * A. IP checksum related features
49 * Drivers advertise checksum offload capabilities in the features of a device.
50 * From the stack's point of view these are capabilities offered by the driver,
51 * a driver typically only advertises features that it is capable of offloading
54 * The checksum related features are:
56 * NETIF_F_HW_CSUM - The driver (or its device) is able to compute one
57 * IP (one's complement) checksum for any combination
58 * of protocols or protocol layering. The checksum is
59 * computed and set in a packet per the CHECKSUM_PARTIAL
60 * interface (see below).
62 * NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain
63 * TCP or UDP packets over IPv4. These are specifically
64 * unencapsulated packets of the form IPv4|TCP or
65 * IPv4|UDP where the Protocol field in the IPv4 header
66 * is TCP or UDP. The IPv4 header may contain IP options
67 * This feature cannot be set in features for a device
68 * with NETIF_F_HW_CSUM also set. This feature is being
69 * DEPRECATED (see below).
71 * NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain
72 * TCP or UDP packets over IPv6. These are specifically
73 * unencapsulated packets of the form IPv6|TCP or
74 * IPv4|UDP where the Next Header field in the IPv6
75 * header is either TCP or UDP. IPv6 extension headers
76 * are not supported with this feature. This feature
77 * cannot be set in features for a device with
78 * NETIF_F_HW_CSUM also set. This feature is being
79 * DEPRECATED (see below).
81 * NETIF_F_RXCSUM - Driver (device) performs receive checksum offload.
82 * This flag is used only used to disable the RX checksum
83 * feature for a device. The stack will accept receive
84 * checksum indication in packets received on a device
85 * regardless of whether NETIF_F_RXCSUM is set.
87 * B. Checksumming of received packets by device. Indication of checksum
88 * verification is in set skb->ip_summed. Possible values are:
92 * Device did not checksum this packet e.g. due to lack of capabilities.
93 * The packet contains full (though not verified) checksum in packet but
94 * not in skb->csum. Thus, skb->csum is undefined in this case.
96 * CHECKSUM_UNNECESSARY:
98 * The hardware you're dealing with doesn't calculate the full checksum
99 * (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
100 * for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
101 * if their checksums are okay. skb->csum is still undefined in this case
102 * though. A driver or device must never modify the checksum field in the
103 * packet even if checksum is verified.
105 * CHECKSUM_UNNECESSARY is applicable to following protocols:
106 * TCP: IPv6 and IPv4.
107 * UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
108 * zero UDP checksum for either IPv4 or IPv6, the networking stack
109 * may perform further validation in this case.
110 * GRE: only if the checksum is present in the header.
111 * SCTP: indicates the CRC in SCTP header has been validated.
112 * FCOE: indicates the CRC in FC frame has been validated.
114 * skb->csum_level indicates the number of consecutive checksums found in
115 * the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
116 * For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
117 * and a device is able to verify the checksums for UDP (possibly zero),
118 * GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
119 * two. If the device were only able to verify the UDP checksum and not
120 * GRE, either because it doesn't support GRE checksum of because GRE
121 * checksum is bad, skb->csum_level would be set to zero (TCP checksum is
122 * not considered in this case).
126 * This is the most generic way. The device supplied checksum of the _whole_
127 * packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
128 * hardware doesn't need to parse L3/L4 headers to implement this.
131 * - Even if device supports only some protocols, but is able to produce
132 * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
133 * - CHECKSUM_COMPLETE is not applicable to SCTP and FCoE protocols.
137 * A checksum is set up to be offloaded to a device as described in the
138 * output description for CHECKSUM_PARTIAL. This may occur on a packet
139 * received directly from another Linux OS, e.g., a virtualized Linux kernel
140 * on the same host, or it may be set in the input path in GRO or remote
141 * checksum offload. For the purposes of checksum verification, the checksum
142 * referred to by skb->csum_start + skb->csum_offset and any preceding
143 * checksums in the packet are considered verified. Any checksums in the
144 * packet that are after the checksum being offloaded are not considered to
147 * C. Checksumming on transmit for non-GSO. The stack requests checksum offload
148 * in the skb->ip_summed for a packet. Values are:
152 * The driver is required to checksum the packet as seen by hard_start_xmit()
153 * from skb->csum_start up to the end, and to record/write the checksum at
154 * offset skb->csum_start + skb->csum_offset. A driver may verify that the
155 * csum_start and csum_offset values are valid values given the length and
156 * offset of the packet, however they should not attempt to validate that the
157 * checksum refers to a legitimate transport layer checksum-- it is the
158 * purview of the stack to validate that csum_start and csum_offset are set
161 * When the stack requests checksum offload for a packet, the driver MUST
162 * ensure that the checksum is set correctly. A driver can either offload the
163 * checksum calculation to the device, or call skb_checksum_help (in the case
164 * that the device does not support offload for a particular checksum).
166 * NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of
167 * NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate
168 * checksum offload capability.
169 * skb_csum_hwoffload_help() can be called to resolve CHECKSUM_PARTIAL based
170 * on network device checksumming capabilities: if a packet does not match
171 * them, skb_checksum_help or skb_crc32c_help (depending on the value of
172 * csum_not_inet, see item D.) is called to resolve the checksum.
176 * The skb was already checksummed by the protocol, or a checksum is not
179 * CHECKSUM_UNNECESSARY:
181 * This has the same meaning on as CHECKSUM_NONE for checksum offload on
185 * Not used in checksum output. If a driver observes a packet with this value
186 * set in skbuff, if should treat as CHECKSUM_NONE being set.
188 * D. Non-IP checksum (CRC) offloads
190 * NETIF_F_SCTP_CRC - This feature indicates that a device is capable of
191 * offloading the SCTP CRC in a packet. To perform this offload the stack
192 * will set set csum_start and csum_offset accordingly, set ip_summed to
193 * CHECKSUM_PARTIAL and set csum_not_inet to 1, to provide an indication in
194 * the skbuff that the CHECKSUM_PARTIAL refers to CRC32c.
195 * A driver that supports both IP checksum offload and SCTP CRC32c offload
196 * must verify which offload is configured for a packet by testing the
197 * value of skb->csum_not_inet; skb_crc32c_csum_help is provided to resolve
198 * CHECKSUM_PARTIAL on skbs where csum_not_inet is set to 1.
200 * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
201 * offloading the FCOE CRC in a packet. To perform this offload the stack
202 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
203 * accordingly. Note the there is no indication in the skbuff that the
204 * CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports
205 * both IP checksum offload and FCOE CRC offload must verify which offload
206 * is configured for a packet presumably by inspecting packet headers.
208 * E. Checksumming on output with GSO.
210 * In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload
211 * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
212 * gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as
213 * part of the GSO operation is implied. If a checksum is being offloaded
214 * with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset
215 * are set to refer to the outermost checksum being offload (two offloaded
216 * checksums are possible with UDP encapsulation).
219 /* Don't change this without changing skb_csum_unnecessary! */
220 #define CHECKSUM_NONE 0
221 #define CHECKSUM_UNNECESSARY 1
222 #define CHECKSUM_COMPLETE 2
223 #define CHECKSUM_PARTIAL 3
225 /* Maximum value in skb->csum_level */
226 #define SKB_MAX_CSUM_LEVEL 3
228 #define SKB_DATA_ALIGN(X) ALIGN(X, SMP_CACHE_BYTES)
229 #define SKB_WITH_OVERHEAD(X) \
230 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
231 #define SKB_MAX_ORDER(X, ORDER) \
232 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
233 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
234 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
236 /* return minimum truesize of one skb containing X bytes of data */
237 #define SKB_TRUESIZE(X) ((X) + \
238 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
239 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
243 struct pipe_inode_info;
250 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
251 struct nf_conntrack {
256 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
257 struct nf_bridge_info {
259 BRNF_PROTO_UNCHANGED,
267 struct net_device *physindev;
269 /* always valid & non-NULL from FORWARD on, for physdev match */
270 struct net_device *physoutdev;
272 /* prerouting: detect dnat in orig/reply direction */
274 struct in6_addr ipv6_daddr;
276 /* after prerouting + nat detected: store original source
277 * mac since neigh resolution overwrites it, only used while
278 * skb is out in neigh layer.
280 char neigh_header[8];
285 struct sk_buff_head {
286 /* These two members must be first. */
287 struct sk_buff *next;
288 struct sk_buff *prev;
296 /* To allow 64K frame to be packed as single skb without frag_list we
297 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
298 * buffers which do not start on a page boundary.
300 * Since GRO uses frags we allocate at least 16 regardless of page
303 #if (65536/PAGE_SIZE + 1) < 16
304 #define MAX_SKB_FRAGS 16UL
306 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
308 extern int sysctl_max_skb_frags;
310 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
311 * segment using its current segmentation instead.
313 #define GSO_BY_FRAGS 0xFFFF
315 typedef struct skb_frag_struct skb_frag_t;
317 struct skb_frag_struct {
321 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
330 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
335 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
340 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
345 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
350 static inline bool skb_frag_must_loop(struct page *p)
352 #if defined(CONFIG_HIGHMEM)
360 * skb_frag_foreach_page - loop over pages in a fragment
362 * @f: skb frag to operate on
363 * @f_off: offset from start of f->page.p
364 * @f_len: length from f_off to loop over
365 * @p: (temp var) current page
366 * @p_off: (temp var) offset from start of current page,
367 * non-zero only on first page.
368 * @p_len: (temp var) length in current page,
369 * < PAGE_SIZE only on first and last page.
370 * @copied: (temp var) length so far, excluding current p_len.
372 * A fragment can hold a compound page, in which case per-page
373 * operations, notably kmap_atomic, must be called for each
376 #define skb_frag_foreach_page(f, f_off, f_len, p, p_off, p_len, copied) \
377 for (p = skb_frag_page(f) + ((f_off) >> PAGE_SHIFT), \
378 p_off = (f_off) & (PAGE_SIZE - 1), \
379 p_len = skb_frag_must_loop(p) ? \
380 min_t(u32, f_len, PAGE_SIZE - p_off) : f_len, \
383 copied += p_len, p++, p_off = 0, \
384 p_len = min_t(u32, f_len - copied, PAGE_SIZE)) \
386 #define HAVE_HW_TIME_STAMP
389 * struct skb_shared_hwtstamps - hardware time stamps
390 * @hwtstamp: hardware time stamp transformed into duration
391 * since arbitrary point in time
393 * Software time stamps generated by ktime_get_real() are stored in
396 * hwtstamps can only be compared against other hwtstamps from
399 * This structure is attached to packets as part of the
400 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
402 struct skb_shared_hwtstamps {
406 /* Definitions for tx_flags in struct skb_shared_info */
408 /* generate hardware time stamp */
409 SKBTX_HW_TSTAMP = 1 << 0,
411 /* generate software time stamp when queueing packet to NIC */
412 SKBTX_SW_TSTAMP = 1 << 1,
414 /* device driver is going to provide hardware time stamp */
415 SKBTX_IN_PROGRESS = 1 << 2,
417 /* device driver supports TX zero-copy buffers */
418 SKBTX_DEV_ZEROCOPY = 1 << 3,
420 /* generate wifi status information (where possible) */
421 SKBTX_WIFI_STATUS = 1 << 4,
423 /* This indicates at least one fragment might be overwritten
424 * (as in vmsplice(), sendfile() ...)
425 * If we need to compute a TX checksum, we'll need to copy
426 * all frags to avoid possible bad checksum
428 SKBTX_SHARED_FRAG = 1 << 5,
430 /* generate software time stamp when entering packet scheduling */
431 SKBTX_SCHED_TSTAMP = 1 << 6,
434 #define SKBTX_ZEROCOPY_FRAG (SKBTX_DEV_ZEROCOPY | SKBTX_SHARED_FRAG)
435 #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
437 #define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
440 * The callback notifies userspace to release buffers when skb DMA is done in
441 * lower device, the skb last reference should be 0 when calling this.
442 * The zerocopy_success argument is true if zero copy transmit occurred,
443 * false on data copy or out of memory error caused by data copy attempt.
444 * The ctx field is used to track device context.
445 * The desc field is used to track userspace buffer index.
448 void (*callback)(struct ubuf_info *, bool zerocopy_success);
464 struct user_struct *user;
469 #define skb_uarg(SKB) ((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg))
471 int mm_account_pinned_pages(struct mmpin *mmp, size_t size);
472 void mm_unaccount_pinned_pages(struct mmpin *mmp);
474 struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size);
475 struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size,
476 struct ubuf_info *uarg);
478 static inline void sock_zerocopy_get(struct ubuf_info *uarg)
480 refcount_inc(&uarg->refcnt);
483 void sock_zerocopy_put(struct ubuf_info *uarg);
484 void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
486 void sock_zerocopy_callback(struct ubuf_info *uarg, bool success);
488 int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len);
489 int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
490 struct msghdr *msg, int len,
491 struct ubuf_info *uarg);
493 /* This data is invariant across clones and lives at
494 * the end of the header data, ie. at skb->end.
496 struct skb_shared_info {
501 unsigned short gso_size;
502 /* Warning: this field is not always filled in (UFO)! */
503 unsigned short gso_segs;
504 struct sk_buff *frag_list;
505 struct skb_shared_hwtstamps hwtstamps;
506 unsigned int gso_type;
510 * Warning : all fields before dataref are cleared in __alloc_skb()
514 /* Intermediate layers must ensure that destructor_arg
515 * remains valid until skb destructor */
516 void * destructor_arg;
518 /* must be last field, see pskb_expand_head() */
519 skb_frag_t frags[MAX_SKB_FRAGS];
522 /* We divide dataref into two halves. The higher 16 bits hold references
523 * to the payload part of skb->data. The lower 16 bits hold references to
524 * the entire skb->data. A clone of a headerless skb holds the length of
525 * the header in skb->hdr_len.
527 * All users must obey the rule that the skb->data reference count must be
528 * greater than or equal to the payload reference count.
530 * Holding a reference to the payload part means that the user does not
531 * care about modifications to the header part of skb->data.
533 #define SKB_DATAREF_SHIFT 16
534 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
538 SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
539 SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */
540 SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */
544 SKB_GSO_TCPV4 = 1 << 0,
546 /* This indicates the skb is from an untrusted source. */
547 SKB_GSO_DODGY = 1 << 1,
549 /* This indicates the tcp segment has CWR set. */
550 SKB_GSO_TCP_ECN = 1 << 2,
552 SKB_GSO_TCP_FIXEDID = 1 << 3,
554 SKB_GSO_TCPV6 = 1 << 4,
556 SKB_GSO_FCOE = 1 << 5,
558 SKB_GSO_GRE = 1 << 6,
560 SKB_GSO_GRE_CSUM = 1 << 7,
562 SKB_GSO_IPXIP4 = 1 << 8,
564 SKB_GSO_IPXIP6 = 1 << 9,
566 SKB_GSO_UDP_TUNNEL = 1 << 10,
568 SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
570 SKB_GSO_PARTIAL = 1 << 12,
572 SKB_GSO_TUNNEL_REMCSUM = 1 << 13,
574 SKB_GSO_SCTP = 1 << 14,
576 SKB_GSO_ESP = 1 << 15,
578 SKB_GSO_UDP = 1 << 16,
580 SKB_GSO_UDP_L4 = 1 << 17,
583 #if BITS_PER_LONG > 32
584 #define NET_SKBUFF_DATA_USES_OFFSET 1
587 #ifdef NET_SKBUFF_DATA_USES_OFFSET
588 typedef unsigned int sk_buff_data_t;
590 typedef unsigned char *sk_buff_data_t;
594 * struct sk_buff - socket buffer
595 * @next: Next buffer in list
596 * @prev: Previous buffer in list
597 * @tstamp: Time we arrived/left
598 * @rbnode: RB tree node, alternative to next/prev for netem/tcp
599 * @sk: Socket we are owned by
600 * @dev: Device we arrived on/are leaving by
601 * @cb: Control buffer. Free for use by every layer. Put private vars here
602 * @_skb_refdst: destination entry (with norefcount bit)
603 * @sp: the security path, used for xfrm
604 * @len: Length of actual data
605 * @data_len: Data length
606 * @mac_len: Length of link layer header
607 * @hdr_len: writable header length of cloned skb
608 * @csum: Checksum (must include start/offset pair)
609 * @csum_start: Offset from skb->head where checksumming should start
610 * @csum_offset: Offset from csum_start where checksum should be stored
611 * @priority: Packet queueing priority
612 * @ignore_df: allow local fragmentation
613 * @cloned: Head may be cloned (check refcnt to be sure)
614 * @ip_summed: Driver fed us an IP checksum
615 * @nohdr: Payload reference only, must not modify header
616 * @pkt_type: Packet class
617 * @fclone: skbuff clone status
618 * @ipvs_property: skbuff is owned by ipvs
619 * @offload_fwd_mark: Packet was L2-forwarded in hardware
620 * @offload_l3_fwd_mark: Packet was L3-forwarded in hardware
621 * @tc_skip_classify: do not classify packet. set by IFB device
622 * @tc_at_ingress: used within tc_classify to distinguish in/egress
623 * @tc_redirected: packet was redirected by a tc action
624 * @tc_from_ingress: if tc_redirected, tc_at_ingress at time of redirect
625 * @peeked: this packet has been seen already, so stats have been
626 * done for it, don't do them again
627 * @nf_trace: netfilter packet trace flag
628 * @protocol: Packet protocol from driver
629 * @destructor: Destruct function
630 * @tcp_tsorted_anchor: list structure for TCP (tp->tsorted_sent_queue)
631 * @_nfct: Associated connection, if any (with nfctinfo bits)
632 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
633 * @skb_iif: ifindex of device we arrived on
634 * @tc_index: Traffic control index
635 * @hash: the packet hash
636 * @queue_mapping: Queue mapping for multiqueue devices
637 * @xmit_more: More SKBs are pending for this queue
638 * @pfmemalloc: skbuff was allocated from PFMEMALLOC reserves
639 * @active_extensions: active extensions (skb_ext_id types)
640 * @ndisc_nodetype: router type (from link layer)
641 * @ooo_okay: allow the mapping of a socket to a queue to be changed
642 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport
644 * @sw_hash: indicates hash was computed in software stack
645 * @wifi_acked_valid: wifi_acked was set
646 * @wifi_acked: whether frame was acked on wifi or not
647 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
648 * @csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL
649 * @dst_pending_confirm: need to confirm neighbour
650 * @decrypted: Decrypted SKB
651 * @napi_id: id of the NAPI struct this skb came from
652 * @secmark: security marking
653 * @mark: Generic packet mark
654 * @vlan_proto: vlan encapsulation protocol
655 * @vlan_tci: vlan tag control information
656 * @inner_protocol: Protocol (encapsulation)
657 * @inner_transport_header: Inner transport layer header (encapsulation)
658 * @inner_network_header: Network layer header (encapsulation)
659 * @inner_mac_header: Link layer header (encapsulation)
660 * @transport_header: Transport layer header
661 * @network_header: Network layer header
662 * @mac_header: Link layer header
663 * @tail: Tail pointer
665 * @head: Head of buffer
666 * @data: Data head pointer
667 * @truesize: Buffer size
668 * @users: User count - see {datagram,tcp}.c
669 * @extensions: allocated extensions, valid if active_extensions is nonzero
675 /* These two members must be first. */
676 struct sk_buff *next;
677 struct sk_buff *prev;
680 struct net_device *dev;
681 /* Some protocols might use this space to store information,
682 * while device pointer would be NULL.
683 * UDP receive path is one user.
685 unsigned long dev_scratch;
688 struct rb_node rbnode; /* used in netem, ip4 defrag, and tcp stack */
689 struct list_head list;
694 int ip_defrag_offset;
699 u64 skb_mstamp_ns; /* earliest departure time */
702 * This is the control buffer. It is free to use for every
703 * layer. Please put your private variables there. If you
704 * want to keep them across layers you have to do a skb_clone()
705 * first. This is owned by whoever has the skb queued ATM.
707 char cb[48] __aligned(8);
711 unsigned long _skb_refdst;
712 void (*destructor)(struct sk_buff *skb);
714 struct list_head tcp_tsorted_anchor;
720 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
728 /* Following fields are _not_ copied in __copy_skb_header()
729 * Note that queue_mapping is here mostly to fill a hole.
733 /* if you move cloned around you also must adapt those constants */
734 #ifdef __BIG_ENDIAN_BITFIELD
735 #define CLONED_MASK (1 << 7)
737 #define CLONED_MASK 1
739 #define CLONED_OFFSET() offsetof(struct sk_buff, __cloned_offset)
741 __u8 __cloned_offset[0];
749 #ifdef CONFIG_SKB_EXTENSIONS
750 __u8 active_extensions;
752 /* fields enclosed in headers_start/headers_end are copied
753 * using a single memcpy() in __copy_skb_header()
756 __u32 headers_start[0];
759 /* if you move pkt_type around you also must adapt those constants */
760 #ifdef __BIG_ENDIAN_BITFIELD
761 #define PKT_TYPE_MAX (7 << 5)
763 #define PKT_TYPE_MAX 7
765 #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
767 __u8 __pkt_type_offset[0];
776 __u8 wifi_acked_valid:1;
779 /* Indicates the inner headers are valid in the skbuff. */
780 __u8 encapsulation:1;
781 __u8 encap_hdr_csum:1;
784 #ifdef __BIG_ENDIAN_BITFIELD
785 #define PKT_VLAN_PRESENT_BIT 7
787 #define PKT_VLAN_PRESENT_BIT 0
789 #define PKT_VLAN_PRESENT_OFFSET() offsetof(struct sk_buff, __pkt_vlan_present_offset)
790 __u8 __pkt_vlan_present_offset[0];
792 __u8 csum_complete_sw:1;
794 __u8 csum_not_inet:1;
795 __u8 dst_pending_confirm:1;
796 #ifdef CONFIG_IPV6_NDISC_NODETYPE
797 __u8 ndisc_nodetype:2;
800 __u8 ipvs_property:1;
801 __u8 inner_protocol_type:1;
802 __u8 remcsum_offload:1;
803 #ifdef CONFIG_NET_SWITCHDEV
804 __u8 offload_fwd_mark:1;
805 __u8 offload_l3_fwd_mark:1;
807 #ifdef CONFIG_NET_CLS_ACT
808 __u8 tc_skip_classify:1;
809 __u8 tc_at_ingress:1;
810 __u8 tc_redirected:1;
811 __u8 tc_from_ingress:1;
813 #ifdef CONFIG_TLS_DEVICE
817 #ifdef CONFIG_NET_SCHED
818 __u16 tc_index; /* traffic control index */
833 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
835 unsigned int napi_id;
836 unsigned int sender_cpu;
839 #ifdef CONFIG_NETWORK_SECMARK
845 __u32 reserved_tailroom;
849 __be16 inner_protocol;
853 __u16 inner_transport_header;
854 __u16 inner_network_header;
855 __u16 inner_mac_header;
858 __u16 transport_header;
859 __u16 network_header;
863 __u32 headers_end[0];
866 /* These elements must be at the end, see alloc_skb() for details. */
871 unsigned int truesize;
874 #ifdef CONFIG_SKB_EXTENSIONS
875 /* only useable after checking ->active_extensions != 0 */
876 struct skb_ext *extensions;
882 * Handling routines are only of interest to the kernel
885 #define SKB_ALLOC_FCLONE 0x01
886 #define SKB_ALLOC_RX 0x02
887 #define SKB_ALLOC_NAPI 0x04
889 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
890 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
892 return unlikely(skb->pfmemalloc);
896 * skb might have a dst pointer attached, refcounted or not.
897 * _skb_refdst low order bit is set if refcount was _not_ taken
899 #define SKB_DST_NOREF 1UL
900 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
902 #define SKB_NFCT_PTRMASK ~(7UL)
904 * skb_dst - returns skb dst_entry
907 * Returns skb dst_entry, regardless of reference taken or not.
909 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
911 /* If refdst was not refcounted, check we still are in a
912 * rcu_read_lock section
914 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
915 !rcu_read_lock_held() &&
916 !rcu_read_lock_bh_held());
917 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
921 * skb_dst_set - sets skb dst
925 * Sets skb dst, assuming a reference was taken on dst and should
926 * be released by skb_dst_drop()
928 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
930 skb->_skb_refdst = (unsigned long)dst;
934 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
938 * Sets skb dst, assuming a reference was not taken on dst.
939 * If dst entry is cached, we do not take reference and dst_release
940 * will be avoided by refdst_drop. If dst entry is not cached, we take
941 * reference, so that last dst_release can destroy the dst immediately.
943 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
945 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
946 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
950 * skb_dst_is_noref - Test if skb dst isn't refcounted
953 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
955 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
958 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
960 return (struct rtable *)skb_dst(skb);
963 /* For mangling skb->pkt_type from user space side from applications
964 * such as nft, tc, etc, we only allow a conservative subset of
965 * possible pkt_types to be set.
967 static inline bool skb_pkt_type_ok(u32 ptype)
969 return ptype <= PACKET_OTHERHOST;
972 static inline unsigned int skb_napi_id(const struct sk_buff *skb)
974 #ifdef CONFIG_NET_RX_BUSY_POLL
981 /* decrement the reference count and return true if we can free the skb */
982 static inline bool skb_unref(struct sk_buff *skb)
986 if (likely(refcount_read(&skb->users) == 1))
988 else if (likely(!refcount_dec_and_test(&skb->users)))
994 void skb_release_head_state(struct sk_buff *skb);
995 void kfree_skb(struct sk_buff *skb);
996 void kfree_skb_list(struct sk_buff *segs);
997 void skb_tx_error(struct sk_buff *skb);
998 void consume_skb(struct sk_buff *skb);
999 void __consume_stateless_skb(struct sk_buff *skb);
1000 void __kfree_skb(struct sk_buff *skb);
1001 extern struct kmem_cache *skbuff_head_cache;
1003 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
1004 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
1005 bool *fragstolen, int *delta_truesize);
1007 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
1009 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
1010 struct sk_buff *build_skb(void *data, unsigned int frag_size);
1011 static inline struct sk_buff *alloc_skb(unsigned int size,
1014 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
1017 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
1018 unsigned long data_len,
1023 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
1024 struct sk_buff_fclones {
1025 struct sk_buff skb1;
1027 struct sk_buff skb2;
1029 refcount_t fclone_ref;
1033 * skb_fclone_busy - check if fclone is busy
1037 * Returns true if skb is a fast clone, and its clone is not freed.
1038 * Some drivers call skb_orphan() in their ndo_start_xmit(),
1039 * so we also check that this didnt happen.
1041 static inline bool skb_fclone_busy(const struct sock *sk,
1042 const struct sk_buff *skb)
1044 const struct sk_buff_fclones *fclones;
1046 fclones = container_of(skb, struct sk_buff_fclones, skb1);
1048 return skb->fclone == SKB_FCLONE_ORIG &&
1049 refcount_read(&fclones->fclone_ref) > 1 &&
1050 fclones->skb2.sk == sk;
1053 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
1056 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
1059 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
1060 void skb_headers_offset_update(struct sk_buff *skb, int off);
1061 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
1062 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
1063 void skb_copy_header(struct sk_buff *new, const struct sk_buff *old);
1064 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
1065 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1066 gfp_t gfp_mask, bool fclone);
1067 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
1070 return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
1073 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
1074 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
1075 unsigned int headroom);
1076 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
1077 int newtailroom, gfp_t priority);
1078 int __must_check skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
1079 int offset, int len);
1080 int __must_check skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg,
1081 int offset, int len);
1082 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
1083 int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error);
1086 * skb_pad - zero pad the tail of an skb
1087 * @skb: buffer to pad
1088 * @pad: space to pad
1090 * Ensure that a buffer is followed by a padding area that is zero
1091 * filled. Used by network drivers which may DMA or transfer data
1092 * beyond the buffer end onto the wire.
1094 * May return error in out of memory cases. The skb is freed on error.
1096 static inline int skb_pad(struct sk_buff *skb, int pad)
1098 return __skb_pad(skb, pad, true);
1100 #define dev_kfree_skb(a) consume_skb(a)
1102 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1103 int offset, size_t size);
1105 struct skb_seq_state {
1109 __u32 stepped_offset;
1110 struct sk_buff *root_skb;
1111 struct sk_buff *cur_skb;
1115 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1116 unsigned int to, struct skb_seq_state *st);
1117 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1118 struct skb_seq_state *st);
1119 void skb_abort_seq_read(struct skb_seq_state *st);
1121 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1122 unsigned int to, struct ts_config *config);
1125 * Packet hash types specify the type of hash in skb_set_hash.
1127 * Hash types refer to the protocol layer addresses which are used to
1128 * construct a packet's hash. The hashes are used to differentiate or identify
1129 * flows of the protocol layer for the hash type. Hash types are either
1130 * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1132 * Properties of hashes:
1134 * 1) Two packets in different flows have different hash values
1135 * 2) Two packets in the same flow should have the same hash value
1137 * A hash at a higher layer is considered to be more specific. A driver should
1138 * set the most specific hash possible.
1140 * A driver cannot indicate a more specific hash than the layer at which a hash
1141 * was computed. For instance an L3 hash cannot be set as an L4 hash.
1143 * A driver may indicate a hash level which is less specific than the
1144 * actual layer the hash was computed on. For instance, a hash computed
1145 * at L4 may be considered an L3 hash. This should only be done if the
1146 * driver can't unambiguously determine that the HW computed the hash at
1147 * the higher layer. Note that the "should" in the second property above
1150 enum pkt_hash_types {
1151 PKT_HASH_TYPE_NONE, /* Undefined type */
1152 PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
1153 PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
1154 PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
1157 static inline void skb_clear_hash(struct sk_buff *skb)
1164 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1167 skb_clear_hash(skb);
1171 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1173 skb->l4_hash = is_l4;
1174 skb->sw_hash = is_sw;
1179 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1181 /* Used by drivers to set hash from HW */
1182 __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1186 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1188 __skb_set_hash(skb, hash, true, is_l4);
1191 void __skb_get_hash(struct sk_buff *skb);
1192 u32 __skb_get_hash_symmetric(const struct sk_buff *skb);
1193 u32 skb_get_poff(const struct sk_buff *skb);
1194 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1195 const struct flow_keys_basic *keys, int hlen);
1196 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1197 void *data, int hlen_proto);
1199 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1200 int thoff, u8 ip_proto)
1202 return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1205 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1206 const struct flow_dissector_key *key,
1207 unsigned int key_count);
1210 int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
1211 struct bpf_prog *prog);
1213 int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr);
1215 static inline int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
1216 struct bpf_prog *prog)
1221 static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
1227 bool __skb_flow_dissect(const struct sk_buff *skb,
1228 struct flow_dissector *flow_dissector,
1229 void *target_container,
1230 void *data, __be16 proto, int nhoff, int hlen,
1231 unsigned int flags);
1233 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1234 struct flow_dissector *flow_dissector,
1235 void *target_container, unsigned int flags)
1237 return __skb_flow_dissect(skb, flow_dissector, target_container,
1238 NULL, 0, 0, 0, flags);
1241 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1242 struct flow_keys *flow,
1245 memset(flow, 0, sizeof(*flow));
1246 return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
1247 NULL, 0, 0, 0, flags);
1251 skb_flow_dissect_flow_keys_basic(const struct sk_buff *skb,
1252 struct flow_keys_basic *flow, void *data,
1253 __be16 proto, int nhoff, int hlen,
1256 memset(flow, 0, sizeof(*flow));
1257 return __skb_flow_dissect(skb, &flow_keys_basic_dissector, flow,
1258 data, proto, nhoff, hlen, flags);
1262 skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
1263 struct flow_dissector *flow_dissector,
1264 void *target_container);
1266 static inline __u32 skb_get_hash(struct sk_buff *skb)
1268 if (!skb->l4_hash && !skb->sw_hash)
1269 __skb_get_hash(skb);
1274 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1276 if (!skb->l4_hash && !skb->sw_hash) {
1277 struct flow_keys keys;
1278 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1280 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1286 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1288 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1293 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1295 to->hash = from->hash;
1296 to->sw_hash = from->sw_hash;
1297 to->l4_hash = from->l4_hash;
1300 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1301 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1303 return skb->head + skb->end;
1306 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1311 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1316 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1318 return skb->end - skb->head;
1323 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1325 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1327 return &skb_shinfo(skb)->hwtstamps;
1330 static inline struct ubuf_info *skb_zcopy(struct sk_buff *skb)
1332 bool is_zcopy = skb && skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY;
1334 return is_zcopy ? skb_uarg(skb) : NULL;
1337 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg,
1340 if (skb && uarg && !skb_zcopy(skb)) {
1341 if (unlikely(have_ref && *have_ref))
1344 sock_zerocopy_get(uarg);
1345 skb_shinfo(skb)->destructor_arg = uarg;
1346 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG;
1350 static inline void skb_zcopy_set_nouarg(struct sk_buff *skb, void *val)
1352 skb_shinfo(skb)->destructor_arg = (void *)((uintptr_t) val | 0x1UL);
1353 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG;
1356 static inline bool skb_zcopy_is_nouarg(struct sk_buff *skb)
1358 return (uintptr_t) skb_shinfo(skb)->destructor_arg & 0x1UL;
1361 static inline void *skb_zcopy_get_nouarg(struct sk_buff *skb)
1363 return (void *)((uintptr_t) skb_shinfo(skb)->destructor_arg & ~0x1UL);
1366 /* Release a reference on a zerocopy structure */
1367 static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
1369 struct ubuf_info *uarg = skb_zcopy(skb);
1372 if (uarg->callback == sock_zerocopy_callback) {
1373 uarg->zerocopy = uarg->zerocopy && zerocopy;
1374 sock_zerocopy_put(uarg);
1375 } else if (!skb_zcopy_is_nouarg(skb)) {
1376 uarg->callback(uarg, zerocopy);
1379 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
1383 /* Abort a zerocopy operation and revert zckey on error in send syscall */
1384 static inline void skb_zcopy_abort(struct sk_buff *skb)
1386 struct ubuf_info *uarg = skb_zcopy(skb);
1389 sock_zerocopy_put_abort(uarg, false);
1390 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
1394 static inline void skb_mark_not_on_list(struct sk_buff *skb)
1399 static inline void skb_list_del_init(struct sk_buff *skb)
1401 __list_del_entry(&skb->list);
1402 skb_mark_not_on_list(skb);
1406 * skb_queue_empty - check if a queue is empty
1409 * Returns true if the queue is empty, false otherwise.
1411 static inline int skb_queue_empty(const struct sk_buff_head *list)
1413 return list->next == (const struct sk_buff *) list;
1417 * skb_queue_is_last - check if skb is the last entry in the queue
1421 * Returns true if @skb is the last buffer on the list.
1423 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1424 const struct sk_buff *skb)
1426 return skb->next == (const struct sk_buff *) list;
1430 * skb_queue_is_first - check if skb is the first entry in the queue
1434 * Returns true if @skb is the first buffer on the list.
1436 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1437 const struct sk_buff *skb)
1439 return skb->prev == (const struct sk_buff *) list;
1443 * skb_queue_next - return the next packet in the queue
1445 * @skb: current buffer
1447 * Return the next packet in @list after @skb. It is only valid to
1448 * call this if skb_queue_is_last() evaluates to false.
1450 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1451 const struct sk_buff *skb)
1453 /* This BUG_ON may seem severe, but if we just return then we
1454 * are going to dereference garbage.
1456 BUG_ON(skb_queue_is_last(list, skb));
1461 * skb_queue_prev - return the prev packet in the queue
1463 * @skb: current buffer
1465 * Return the prev packet in @list before @skb. It is only valid to
1466 * call this if skb_queue_is_first() evaluates to false.
1468 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1469 const struct sk_buff *skb)
1471 /* This BUG_ON may seem severe, but if we just return then we
1472 * are going to dereference garbage.
1474 BUG_ON(skb_queue_is_first(list, skb));
1479 * skb_get - reference buffer
1480 * @skb: buffer to reference
1482 * Makes another reference to a socket buffer and returns a pointer
1485 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1487 refcount_inc(&skb->users);
1492 * If users == 1, we are the only owner and can avoid redundant atomic changes.
1496 * skb_cloned - is the buffer a clone
1497 * @skb: buffer to check
1499 * Returns true if the buffer was generated with skb_clone() and is
1500 * one of multiple shared copies of the buffer. Cloned buffers are
1501 * shared data so must not be written to under normal circumstances.
1503 static inline int skb_cloned(const struct sk_buff *skb)
1505 return skb->cloned &&
1506 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1509 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1511 might_sleep_if(gfpflags_allow_blocking(pri));
1513 if (skb_cloned(skb))
1514 return pskb_expand_head(skb, 0, 0, pri);
1520 * skb_header_cloned - is the header a clone
1521 * @skb: buffer to check
1523 * Returns true if modifying the header part of the buffer requires
1524 * the data to be copied.
1526 static inline int skb_header_cloned(const struct sk_buff *skb)
1533 dataref = atomic_read(&skb_shinfo(skb)->dataref);
1534 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1535 return dataref != 1;
1538 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
1540 might_sleep_if(gfpflags_allow_blocking(pri));
1542 if (skb_header_cloned(skb))
1543 return pskb_expand_head(skb, 0, 0, pri);
1549 * __skb_header_release - release reference to header
1550 * @skb: buffer to operate on
1552 static inline void __skb_header_release(struct sk_buff *skb)
1555 atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1560 * skb_shared - is the buffer shared
1561 * @skb: buffer to check
1563 * Returns true if more than one person has a reference to this
1566 static inline int skb_shared(const struct sk_buff *skb)
1568 return refcount_read(&skb->users) != 1;
1572 * skb_share_check - check if buffer is shared and if so clone it
1573 * @skb: buffer to check
1574 * @pri: priority for memory allocation
1576 * If the buffer is shared the buffer is cloned and the old copy
1577 * drops a reference. A new clone with a single reference is returned.
1578 * If the buffer is not shared the original buffer is returned. When
1579 * being called from interrupt status or with spinlocks held pri must
1582 * NULL is returned on a memory allocation failure.
1584 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1586 might_sleep_if(gfpflags_allow_blocking(pri));
1587 if (skb_shared(skb)) {
1588 struct sk_buff *nskb = skb_clone(skb, pri);
1600 * Copy shared buffers into a new sk_buff. We effectively do COW on
1601 * packets to handle cases where we have a local reader and forward
1602 * and a couple of other messy ones. The normal one is tcpdumping
1603 * a packet thats being forwarded.
1607 * skb_unshare - make a copy of a shared buffer
1608 * @skb: buffer to check
1609 * @pri: priority for memory allocation
1611 * If the socket buffer is a clone then this function creates a new
1612 * copy of the data, drops a reference count on the old copy and returns
1613 * the new copy with the reference count at 1. If the buffer is not a clone
1614 * the original buffer is returned. When called with a spinlock held or
1615 * from interrupt state @pri must be %GFP_ATOMIC
1617 * %NULL is returned on a memory allocation failure.
1619 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1622 might_sleep_if(gfpflags_allow_blocking(pri));
1623 if (skb_cloned(skb)) {
1624 struct sk_buff *nskb = skb_copy(skb, pri);
1626 /* Free our shared copy */
1637 * skb_peek - peek at the head of an &sk_buff_head
1638 * @list_: list to peek at
1640 * Peek an &sk_buff. Unlike most other operations you _MUST_
1641 * be careful with this one. A peek leaves the buffer on the
1642 * list and someone else may run off with it. You must hold
1643 * the appropriate locks or have a private queue to do this.
1645 * Returns %NULL for an empty list or a pointer to the head element.
1646 * The reference count is not incremented and the reference is therefore
1647 * volatile. Use with caution.
1649 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1651 struct sk_buff *skb = list_->next;
1653 if (skb == (struct sk_buff *)list_)
1659 * __skb_peek - peek at the head of a non-empty &sk_buff_head
1660 * @list_: list to peek at
1662 * Like skb_peek(), but the caller knows that the list is not empty.
1664 static inline struct sk_buff *__skb_peek(const struct sk_buff_head *list_)
1670 * skb_peek_next - peek skb following the given one from a queue
1671 * @skb: skb to start from
1672 * @list_: list to peek at
1674 * Returns %NULL when the end of the list is met or a pointer to the
1675 * next element. The reference count is not incremented and the
1676 * reference is therefore volatile. Use with caution.
1678 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1679 const struct sk_buff_head *list_)
1681 struct sk_buff *next = skb->next;
1683 if (next == (struct sk_buff *)list_)
1689 * skb_peek_tail - peek at the tail of an &sk_buff_head
1690 * @list_: list to peek at
1692 * Peek an &sk_buff. Unlike most other operations you _MUST_
1693 * be careful with this one. A peek leaves the buffer on the
1694 * list and someone else may run off with it. You must hold
1695 * the appropriate locks or have a private queue to do this.
1697 * Returns %NULL for an empty list or a pointer to the tail element.
1698 * The reference count is not incremented and the reference is therefore
1699 * volatile. Use with caution.
1701 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1703 struct sk_buff *skb = list_->prev;
1705 if (skb == (struct sk_buff *)list_)
1712 * skb_queue_len - get queue length
1713 * @list_: list to measure
1715 * Return the length of an &sk_buff queue.
1717 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1723 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1724 * @list: queue to initialize
1726 * This initializes only the list and queue length aspects of
1727 * an sk_buff_head object. This allows to initialize the list
1728 * aspects of an sk_buff_head without reinitializing things like
1729 * the spinlock. It can also be used for on-stack sk_buff_head
1730 * objects where the spinlock is known to not be used.
1732 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1734 list->prev = list->next = (struct sk_buff *)list;
1739 * This function creates a split out lock class for each invocation;
1740 * this is needed for now since a whole lot of users of the skb-queue
1741 * infrastructure in drivers have different locking usage (in hardirq)
1742 * than the networking core (in softirq only). In the long run either the
1743 * network layer or drivers should need annotation to consolidate the
1744 * main types of usage into 3 classes.
1746 static inline void skb_queue_head_init(struct sk_buff_head *list)
1748 spin_lock_init(&list->lock);
1749 __skb_queue_head_init(list);
1752 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1753 struct lock_class_key *class)
1755 skb_queue_head_init(list);
1756 lockdep_set_class(&list->lock, class);
1760 * Insert an sk_buff on a list.
1762 * The "__skb_xxxx()" functions are the non-atomic ones that
1763 * can only be called with interrupts disabled.
1765 static inline void __skb_insert(struct sk_buff *newsk,
1766 struct sk_buff *prev, struct sk_buff *next,
1767 struct sk_buff_head *list)
1771 next->prev = prev->next = newsk;
1775 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1776 struct sk_buff *prev,
1777 struct sk_buff *next)
1779 struct sk_buff *first = list->next;
1780 struct sk_buff *last = list->prev;
1790 * skb_queue_splice - join two skb lists, this is designed for stacks
1791 * @list: the new list to add
1792 * @head: the place to add it in the first list
1794 static inline void skb_queue_splice(const struct sk_buff_head *list,
1795 struct sk_buff_head *head)
1797 if (!skb_queue_empty(list)) {
1798 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1799 head->qlen += list->qlen;
1804 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1805 * @list: the new list to add
1806 * @head: the place to add it in the first list
1808 * The list at @list is reinitialised
1810 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1811 struct sk_buff_head *head)
1813 if (!skb_queue_empty(list)) {
1814 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1815 head->qlen += list->qlen;
1816 __skb_queue_head_init(list);
1821 * skb_queue_splice_tail - join two skb lists, each list being a queue
1822 * @list: the new list to add
1823 * @head: the place to add it in the first list
1825 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1826 struct sk_buff_head *head)
1828 if (!skb_queue_empty(list)) {
1829 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1830 head->qlen += list->qlen;
1835 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1836 * @list: the new list to add
1837 * @head: the place to add it in the first list
1839 * Each of the lists is a queue.
1840 * The list at @list is reinitialised
1842 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1843 struct sk_buff_head *head)
1845 if (!skb_queue_empty(list)) {
1846 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1847 head->qlen += list->qlen;
1848 __skb_queue_head_init(list);
1853 * __skb_queue_after - queue a buffer at the list head
1854 * @list: list to use
1855 * @prev: place after this buffer
1856 * @newsk: buffer to queue
1858 * Queue a buffer int the middle of a list. This function takes no locks
1859 * and you must therefore hold required locks before calling it.
1861 * A buffer cannot be placed on two lists at the same time.
1863 static inline void __skb_queue_after(struct sk_buff_head *list,
1864 struct sk_buff *prev,
1865 struct sk_buff *newsk)
1867 __skb_insert(newsk, prev, prev->next, list);
1870 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1871 struct sk_buff_head *list);
1873 static inline void __skb_queue_before(struct sk_buff_head *list,
1874 struct sk_buff *next,
1875 struct sk_buff *newsk)
1877 __skb_insert(newsk, next->prev, next, list);
1881 * __skb_queue_head - queue a buffer at the list head
1882 * @list: list to use
1883 * @newsk: buffer to queue
1885 * Queue a buffer at the start of a list. This function takes no locks
1886 * and you must therefore hold required locks before calling it.
1888 * A buffer cannot be placed on two lists at the same time.
1890 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1891 static inline void __skb_queue_head(struct sk_buff_head *list,
1892 struct sk_buff *newsk)
1894 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1898 * __skb_queue_tail - queue a buffer at the list tail
1899 * @list: list to use
1900 * @newsk: buffer to queue
1902 * Queue a buffer at the end of a list. This function takes no locks
1903 * and you must therefore hold required locks before calling it.
1905 * A buffer cannot be placed on two lists at the same time.
1907 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1908 static inline void __skb_queue_tail(struct sk_buff_head *list,
1909 struct sk_buff *newsk)
1911 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1915 * remove sk_buff from list. _Must_ be called atomically, and with
1918 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1919 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1921 struct sk_buff *next, *prev;
1926 skb->next = skb->prev = NULL;
1932 * __skb_dequeue - remove from the head of the queue
1933 * @list: list to dequeue from
1935 * Remove the head of the list. This function does not take any locks
1936 * so must be used with appropriate locks held only. The head item is
1937 * returned or %NULL if the list is empty.
1939 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1940 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1942 struct sk_buff *skb = skb_peek(list);
1944 __skb_unlink(skb, list);
1949 * __skb_dequeue_tail - remove from the tail of the queue
1950 * @list: list to dequeue from
1952 * Remove the tail of the list. This function does not take any locks
1953 * so must be used with appropriate locks held only. The tail item is
1954 * returned or %NULL if the list is empty.
1956 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1957 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1959 struct sk_buff *skb = skb_peek_tail(list);
1961 __skb_unlink(skb, list);
1966 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1968 return skb->data_len;
1971 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1973 return skb->len - skb->data_len;
1976 static inline unsigned int __skb_pagelen(const struct sk_buff *skb)
1978 unsigned int i, len = 0;
1980 for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--)
1981 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1985 static inline unsigned int skb_pagelen(const struct sk_buff *skb)
1987 return skb_headlen(skb) + __skb_pagelen(skb);
1991 * __skb_fill_page_desc - initialise a paged fragment in an skb
1992 * @skb: buffer containing fragment to be initialised
1993 * @i: paged fragment index to initialise
1994 * @page: the page to use for this fragment
1995 * @off: the offset to the data with @page
1996 * @size: the length of the data
1998 * Initialises the @i'th fragment of @skb to point to &size bytes at
1999 * offset @off within @page.
2001 * Does not take any additional reference on the fragment.
2003 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
2004 struct page *page, int off, int size)
2006 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2009 * Propagate page pfmemalloc to the skb if we can. The problem is
2010 * that not all callers have unique ownership of the page but rely
2011 * on page_is_pfmemalloc doing the right thing(tm).
2013 frag->page.p = page;
2014 frag->page_offset = off;
2015 skb_frag_size_set(frag, size);
2017 page = compound_head(page);
2018 if (page_is_pfmemalloc(page))
2019 skb->pfmemalloc = true;
2023 * skb_fill_page_desc - initialise a paged fragment in an skb
2024 * @skb: buffer containing fragment to be initialised
2025 * @i: paged fragment index to initialise
2026 * @page: the page to use for this fragment
2027 * @off: the offset to the data with @page
2028 * @size: the length of the data
2030 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
2031 * @skb to point to @size bytes at offset @off within @page. In
2032 * addition updates @skb such that @i is the last fragment.
2034 * Does not take any additional reference on the fragment.
2036 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
2037 struct page *page, int off, int size)
2039 __skb_fill_page_desc(skb, i, page, off, size);
2040 skb_shinfo(skb)->nr_frags = i + 1;
2043 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
2044 int size, unsigned int truesize);
2046 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
2047 unsigned int truesize);
2049 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
2050 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
2051 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
2053 #ifdef NET_SKBUFF_DATA_USES_OFFSET
2054 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2056 return skb->head + skb->tail;
2059 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2061 skb->tail = skb->data - skb->head;
2064 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2066 skb_reset_tail_pointer(skb);
2067 skb->tail += offset;
2070 #else /* NET_SKBUFF_DATA_USES_OFFSET */
2071 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2076 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2078 skb->tail = skb->data;
2081 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2083 skb->tail = skb->data + offset;
2086 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
2089 * Add data to an sk_buff
2091 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
2092 void *skb_put(struct sk_buff *skb, unsigned int len);
2093 static inline void *__skb_put(struct sk_buff *skb, unsigned int len)
2095 void *tmp = skb_tail_pointer(skb);
2096 SKB_LINEAR_ASSERT(skb);
2102 static inline void *__skb_put_zero(struct sk_buff *skb, unsigned int len)
2104 void *tmp = __skb_put(skb, len);
2106 memset(tmp, 0, len);
2110 static inline void *__skb_put_data(struct sk_buff *skb, const void *data,
2113 void *tmp = __skb_put(skb, len);
2115 memcpy(tmp, data, len);
2119 static inline void __skb_put_u8(struct sk_buff *skb, u8 val)
2121 *(u8 *)__skb_put(skb, 1) = val;
2124 static inline void *skb_put_zero(struct sk_buff *skb, unsigned int len)
2126 void *tmp = skb_put(skb, len);
2128 memset(tmp, 0, len);
2133 static inline void *skb_put_data(struct sk_buff *skb, const void *data,
2136 void *tmp = skb_put(skb, len);
2138 memcpy(tmp, data, len);
2143 static inline void skb_put_u8(struct sk_buff *skb, u8 val)
2145 *(u8 *)skb_put(skb, 1) = val;
2148 void *skb_push(struct sk_buff *skb, unsigned int len);
2149 static inline void *__skb_push(struct sk_buff *skb, unsigned int len)
2156 void *skb_pull(struct sk_buff *skb, unsigned int len);
2157 static inline void *__skb_pull(struct sk_buff *skb, unsigned int len)
2160 BUG_ON(skb->len < skb->data_len);
2161 return skb->data += len;
2164 static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len)
2166 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
2169 void *__pskb_pull_tail(struct sk_buff *skb, int delta);
2171 static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len)
2173 if (len > skb_headlen(skb) &&
2174 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
2177 return skb->data += len;
2180 static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
2182 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
2185 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
2187 if (likely(len <= skb_headlen(skb)))
2189 if (unlikely(len > skb->len))
2191 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
2194 void skb_condense(struct sk_buff *skb);
2197 * skb_headroom - bytes at buffer head
2198 * @skb: buffer to check
2200 * Return the number of bytes of free space at the head of an &sk_buff.
2202 static inline unsigned int skb_headroom(const struct sk_buff *skb)
2204 return skb->data - skb->head;
2208 * skb_tailroom - bytes at buffer end
2209 * @skb: buffer to check
2211 * Return the number of bytes of free space at the tail of an sk_buff
2213 static inline int skb_tailroom(const struct sk_buff *skb)
2215 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
2219 * skb_availroom - bytes at buffer end
2220 * @skb: buffer to check
2222 * Return the number of bytes of free space at the tail of an sk_buff
2223 * allocated by sk_stream_alloc()
2225 static inline int skb_availroom(const struct sk_buff *skb)
2227 if (skb_is_nonlinear(skb))
2230 return skb->end - skb->tail - skb->reserved_tailroom;
2234 * skb_reserve - adjust headroom
2235 * @skb: buffer to alter
2236 * @len: bytes to move
2238 * Increase the headroom of an empty &sk_buff by reducing the tail
2239 * room. This is only allowed for an empty buffer.
2241 static inline void skb_reserve(struct sk_buff *skb, int len)
2248 * skb_tailroom_reserve - adjust reserved_tailroom
2249 * @skb: buffer to alter
2250 * @mtu: maximum amount of headlen permitted
2251 * @needed_tailroom: minimum amount of reserved_tailroom
2253 * Set reserved_tailroom so that headlen can be as large as possible but
2254 * not larger than mtu and tailroom cannot be smaller than
2256 * The required headroom should already have been reserved before using
2259 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2260 unsigned int needed_tailroom)
2262 SKB_LINEAR_ASSERT(skb);
2263 if (mtu < skb_tailroom(skb) - needed_tailroom)
2264 /* use at most mtu */
2265 skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2267 /* use up to all available space */
2268 skb->reserved_tailroom = needed_tailroom;
2271 #define ENCAP_TYPE_ETHER 0
2272 #define ENCAP_TYPE_IPPROTO 1
2274 static inline void skb_set_inner_protocol(struct sk_buff *skb,
2277 skb->inner_protocol = protocol;
2278 skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2281 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2284 skb->inner_ipproto = ipproto;
2285 skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2288 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2290 skb->inner_mac_header = skb->mac_header;
2291 skb->inner_network_header = skb->network_header;
2292 skb->inner_transport_header = skb->transport_header;
2295 static inline void skb_reset_mac_len(struct sk_buff *skb)
2297 skb->mac_len = skb->network_header - skb->mac_header;
2300 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2303 return skb->head + skb->inner_transport_header;
2306 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2308 return skb_inner_transport_header(skb) - skb->data;
2311 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2313 skb->inner_transport_header = skb->data - skb->head;
2316 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2319 skb_reset_inner_transport_header(skb);
2320 skb->inner_transport_header += offset;
2323 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2325 return skb->head + skb->inner_network_header;
2328 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2330 skb->inner_network_header = skb->data - skb->head;
2333 static inline void skb_set_inner_network_header(struct sk_buff *skb,
2336 skb_reset_inner_network_header(skb);
2337 skb->inner_network_header += offset;
2340 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2342 return skb->head + skb->inner_mac_header;
2345 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2347 skb->inner_mac_header = skb->data - skb->head;
2350 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2353 skb_reset_inner_mac_header(skb);
2354 skb->inner_mac_header += offset;
2356 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2358 return skb->transport_header != (typeof(skb->transport_header))~0U;
2361 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2363 return skb->head + skb->transport_header;
2366 static inline void skb_reset_transport_header(struct sk_buff *skb)
2368 skb->transport_header = skb->data - skb->head;
2371 static inline void skb_set_transport_header(struct sk_buff *skb,
2374 skb_reset_transport_header(skb);
2375 skb->transport_header += offset;
2378 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2380 return skb->head + skb->network_header;
2383 static inline void skb_reset_network_header(struct sk_buff *skb)
2385 skb->network_header = skb->data - skb->head;
2388 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2390 skb_reset_network_header(skb);
2391 skb->network_header += offset;
2394 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2396 return skb->head + skb->mac_header;
2399 static inline int skb_mac_offset(const struct sk_buff *skb)
2401 return skb_mac_header(skb) - skb->data;
2404 static inline u32 skb_mac_header_len(const struct sk_buff *skb)
2406 return skb->network_header - skb->mac_header;
2409 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2411 return skb->mac_header != (typeof(skb->mac_header))~0U;
2414 static inline void skb_reset_mac_header(struct sk_buff *skb)
2416 skb->mac_header = skb->data - skb->head;
2419 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2421 skb_reset_mac_header(skb);
2422 skb->mac_header += offset;
2425 static inline void skb_pop_mac_header(struct sk_buff *skb)
2427 skb->mac_header = skb->network_header;
2430 static inline void skb_probe_transport_header(struct sk_buff *skb,
2431 const int offset_hint)
2433 struct flow_keys_basic keys;
2435 if (skb_transport_header_was_set(skb))
2438 if (skb_flow_dissect_flow_keys_basic(skb, &keys, NULL, 0, 0, 0, 0))
2439 skb_set_transport_header(skb, keys.control.thoff);
2441 skb_set_transport_header(skb, offset_hint);
2444 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2446 if (skb_mac_header_was_set(skb)) {
2447 const unsigned char *old_mac = skb_mac_header(skb);
2449 skb_set_mac_header(skb, -skb->mac_len);
2450 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2454 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2456 return skb->csum_start - skb_headroom(skb);
2459 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
2461 return skb->head + skb->csum_start;
2464 static inline int skb_transport_offset(const struct sk_buff *skb)
2466 return skb_transport_header(skb) - skb->data;
2469 static inline u32 skb_network_header_len(const struct sk_buff *skb)
2471 return skb->transport_header - skb->network_header;
2474 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2476 return skb->inner_transport_header - skb->inner_network_header;
2479 static inline int skb_network_offset(const struct sk_buff *skb)
2481 return skb_network_header(skb) - skb->data;
2484 static inline int skb_inner_network_offset(const struct sk_buff *skb)
2486 return skb_inner_network_header(skb) - skb->data;
2489 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2491 return pskb_may_pull(skb, skb_network_offset(skb) + len);
2495 * CPUs often take a performance hit when accessing unaligned memory
2496 * locations. The actual performance hit varies, it can be small if the
2497 * hardware handles it or large if we have to take an exception and fix it
2500 * Since an ethernet header is 14 bytes network drivers often end up with
2501 * the IP header at an unaligned offset. The IP header can be aligned by
2502 * shifting the start of the packet by 2 bytes. Drivers should do this
2505 * skb_reserve(skb, NET_IP_ALIGN);
2507 * The downside to this alignment of the IP header is that the DMA is now
2508 * unaligned. On some architectures the cost of an unaligned DMA is high
2509 * and this cost outweighs the gains made by aligning the IP header.
2511 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2514 #ifndef NET_IP_ALIGN
2515 #define NET_IP_ALIGN 2
2519 * The networking layer reserves some headroom in skb data (via
2520 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2521 * the header has to grow. In the default case, if the header has to grow
2522 * 32 bytes or less we avoid the reallocation.
2524 * Unfortunately this headroom changes the DMA alignment of the resulting
2525 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2526 * on some architectures. An architecture can override this value,
2527 * perhaps setting it to a cacheline in size (since that will maintain
2528 * cacheline alignment of the DMA). It must be a power of 2.
2530 * Various parts of the networking layer expect at least 32 bytes of
2531 * headroom, you should not reduce this.
2533 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2534 * to reduce average number of cache lines per packet.
2535 * get_rps_cpus() for example only access one 64 bytes aligned block :
2536 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2539 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
2542 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2544 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
2546 if (WARN_ON(skb_is_nonlinear(skb)))
2549 skb_set_tail_pointer(skb, len);
2552 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2554 __skb_set_length(skb, len);
2557 void skb_trim(struct sk_buff *skb, unsigned int len);
2559 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2562 return ___pskb_trim(skb, len);
2563 __skb_trim(skb, len);
2567 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2569 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2573 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2574 * @skb: buffer to alter
2577 * This is identical to pskb_trim except that the caller knows that
2578 * the skb is not cloned so we should never get an error due to out-
2581 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2583 int err = pskb_trim(skb, len);
2587 static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
2589 unsigned int diff = len - skb->len;
2591 if (skb_tailroom(skb) < diff) {
2592 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
2597 __skb_set_length(skb, len);
2602 * skb_orphan - orphan a buffer
2603 * @skb: buffer to orphan
2605 * If a buffer currently has an owner then we call the owner's
2606 * destructor function and make the @skb unowned. The buffer continues
2607 * to exist but is no longer charged to its former owner.
2609 static inline void skb_orphan(struct sk_buff *skb)
2611 if (skb->destructor) {
2612 skb->destructor(skb);
2613 skb->destructor = NULL;
2621 * skb_orphan_frags - orphan the frags contained in a buffer
2622 * @skb: buffer to orphan frags from
2623 * @gfp_mask: allocation mask for replacement pages
2625 * For each frag in the SKB which needs a destructor (i.e. has an
2626 * owner) create a copy of that frag and release the original
2627 * page by calling the destructor.
2629 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2631 if (likely(!skb_zcopy(skb)))
2633 if (skb_uarg(skb)->callback == sock_zerocopy_callback)
2635 return skb_copy_ubufs(skb, gfp_mask);
2638 /* Frags must be orphaned, even if refcounted, if skb might loop to rx path */
2639 static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask)
2641 if (likely(!skb_zcopy(skb)))
2643 return skb_copy_ubufs(skb, gfp_mask);
2647 * __skb_queue_purge - empty a list
2648 * @list: list to empty
2650 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2651 * the list and one reference dropped. This function does not take the
2652 * list lock and the caller must hold the relevant locks to use it.
2654 void skb_queue_purge(struct sk_buff_head *list);
2655 static inline void __skb_queue_purge(struct sk_buff_head *list)
2657 struct sk_buff *skb;
2658 while ((skb = __skb_dequeue(list)) != NULL)
2662 unsigned int skb_rbtree_purge(struct rb_root *root);
2664 void *netdev_alloc_frag(unsigned int fragsz);
2666 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2670 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
2671 * @dev: network device to receive on
2672 * @length: length to allocate
2674 * Allocate a new &sk_buff and assign it a usage count of one. The
2675 * buffer has unspecified headroom built in. Users should allocate
2676 * the headroom they think they need without accounting for the
2677 * built in space. The built in space is used for optimisations.
2679 * %NULL is returned if there is no free memory. Although this function
2680 * allocates memory it can be called from an interrupt.
2682 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2683 unsigned int length)
2685 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2688 /* legacy helper around __netdev_alloc_skb() */
2689 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2692 return __netdev_alloc_skb(NULL, length, gfp_mask);
2695 /* legacy helper around netdev_alloc_skb() */
2696 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2698 return netdev_alloc_skb(NULL, length);
2702 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2703 unsigned int length, gfp_t gfp)
2705 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2707 if (NET_IP_ALIGN && skb)
2708 skb_reserve(skb, NET_IP_ALIGN);
2712 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2713 unsigned int length)
2715 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2718 static inline void skb_free_frag(void *addr)
2720 page_frag_free(addr);
2723 void *napi_alloc_frag(unsigned int fragsz);
2724 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2725 unsigned int length, gfp_t gfp_mask);
2726 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2727 unsigned int length)
2729 return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2731 void napi_consume_skb(struct sk_buff *skb, int budget);
2733 void __kfree_skb_flush(void);
2734 void __kfree_skb_defer(struct sk_buff *skb);
2737 * __dev_alloc_pages - allocate page for network Rx
2738 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2739 * @order: size of the allocation
2741 * Allocate a new page.
2743 * %NULL is returned if there is no free memory.
2745 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2748 /* This piece of code contains several assumptions.
2749 * 1. This is for device Rx, therefor a cold page is preferred.
2750 * 2. The expectation is the user wants a compound page.
2751 * 3. If requesting a order 0 page it will not be compound
2752 * due to the check to see if order has a value in prep_new_page
2753 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2754 * code in gfp_to_alloc_flags that should be enforcing this.
2756 gfp_mask |= __GFP_COMP | __GFP_MEMALLOC;
2758 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2761 static inline struct page *dev_alloc_pages(unsigned int order)
2763 return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
2767 * __dev_alloc_page - allocate a page for network Rx
2768 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2770 * Allocate a new page.
2772 * %NULL is returned if there is no free memory.
2774 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2776 return __dev_alloc_pages(gfp_mask, 0);
2779 static inline struct page *dev_alloc_page(void)
2781 return dev_alloc_pages(0);
2785 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2786 * @page: The page that was allocated from skb_alloc_page
2787 * @skb: The skb that may need pfmemalloc set
2789 static inline void skb_propagate_pfmemalloc(struct page *page,
2790 struct sk_buff *skb)
2792 if (page_is_pfmemalloc(page))
2793 skb->pfmemalloc = true;
2797 * skb_frag_page - retrieve the page referred to by a paged fragment
2798 * @frag: the paged fragment
2800 * Returns the &struct page associated with @frag.
2802 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2804 return frag->page.p;
2808 * __skb_frag_ref - take an addition reference on a paged fragment.
2809 * @frag: the paged fragment
2811 * Takes an additional reference on the paged fragment @frag.
2813 static inline void __skb_frag_ref(skb_frag_t *frag)
2815 get_page(skb_frag_page(frag));
2819 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2821 * @f: the fragment offset.
2823 * Takes an additional reference on the @f'th paged fragment of @skb.
2825 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2827 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2831 * __skb_frag_unref - release a reference on a paged fragment.
2832 * @frag: the paged fragment
2834 * Releases a reference on the paged fragment @frag.
2836 static inline void __skb_frag_unref(skb_frag_t *frag)
2838 put_page(skb_frag_page(frag));
2842 * skb_frag_unref - release a reference on a paged fragment of an skb.
2844 * @f: the fragment offset
2846 * Releases a reference on the @f'th paged fragment of @skb.
2848 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2850 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2854 * skb_frag_address - gets the address of the data contained in a paged fragment
2855 * @frag: the paged fragment buffer
2857 * Returns the address of the data within @frag. The page must already
2860 static inline void *skb_frag_address(const skb_frag_t *frag)
2862 return page_address(skb_frag_page(frag)) + frag->page_offset;
2866 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2867 * @frag: the paged fragment buffer
2869 * Returns the address of the data within @frag. Checks that the page
2870 * is mapped and returns %NULL otherwise.
2872 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2874 void *ptr = page_address(skb_frag_page(frag));
2878 return ptr + frag->page_offset;
2882 * __skb_frag_set_page - sets the page contained in a paged fragment
2883 * @frag: the paged fragment
2884 * @page: the page to set
2886 * Sets the fragment @frag to contain @page.
2888 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2890 frag->page.p = page;
2894 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2896 * @f: the fragment offset
2897 * @page: the page to set
2899 * Sets the @f'th fragment of @skb to contain @page.
2901 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2904 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2907 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2910 * skb_frag_dma_map - maps a paged fragment via the DMA API
2911 * @dev: the device to map the fragment to
2912 * @frag: the paged fragment to map
2913 * @offset: the offset within the fragment (starting at the
2914 * fragment's own offset)
2915 * @size: the number of bytes to map
2916 * @dir: the direction of the mapping (``PCI_DMA_*``)
2918 * Maps the page associated with @frag to @device.
2920 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2921 const skb_frag_t *frag,
2922 size_t offset, size_t size,
2923 enum dma_data_direction dir)
2925 return dma_map_page(dev, skb_frag_page(frag),
2926 frag->page_offset + offset, size, dir);
2929 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2932 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2936 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
2939 return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
2944 * skb_clone_writable - is the header of a clone writable
2945 * @skb: buffer to check
2946 * @len: length up to which to write
2948 * Returns true if modifying the header part of the cloned buffer
2949 * does not requires the data to be copied.
2951 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2953 return !skb_header_cloned(skb) &&
2954 skb_headroom(skb) + len <= skb->hdr_len;
2957 static inline int skb_try_make_writable(struct sk_buff *skb,
2958 unsigned int write_len)
2960 return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
2961 pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2964 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2969 if (headroom > skb_headroom(skb))
2970 delta = headroom - skb_headroom(skb);
2972 if (delta || cloned)
2973 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2979 * skb_cow - copy header of skb when it is required
2980 * @skb: buffer to cow
2981 * @headroom: needed headroom
2983 * If the skb passed lacks sufficient headroom or its data part
2984 * is shared, data is reallocated. If reallocation fails, an error
2985 * is returned and original skb is not changed.
2987 * The result is skb with writable area skb->head...skb->tail
2988 * and at least @headroom of space at head.
2990 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2992 return __skb_cow(skb, headroom, skb_cloned(skb));
2996 * skb_cow_head - skb_cow but only making the head writable
2997 * @skb: buffer to cow
2998 * @headroom: needed headroom
3000 * This function is identical to skb_cow except that we replace the
3001 * skb_cloned check by skb_header_cloned. It should be used when
3002 * you only need to push on some header and do not need to modify
3005 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
3007 return __skb_cow(skb, headroom, skb_header_cloned(skb));
3011 * skb_padto - pad an skbuff up to a minimal size
3012 * @skb: buffer to pad
3013 * @len: minimal length
3015 * Pads up a buffer to ensure the trailing bytes exist and are
3016 * blanked. If the buffer already contains sufficient data it
3017 * is untouched. Otherwise it is extended. Returns zero on
3018 * success. The skb is freed on error.
3020 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
3022 unsigned int size = skb->len;
3023 if (likely(size >= len))
3025 return skb_pad(skb, len - size);
3029 * skb_put_padto - increase size and pad an skbuff up to a minimal size
3030 * @skb: buffer to pad
3031 * @len: minimal length
3032 * @free_on_error: free buffer on error
3034 * Pads up a buffer to ensure the trailing bytes exist and are
3035 * blanked. If the buffer already contains sufficient data it
3036 * is untouched. Otherwise it is extended. Returns zero on
3037 * success. The skb is freed on error if @free_on_error is true.
3039 static inline int __skb_put_padto(struct sk_buff *skb, unsigned int len,
3042 unsigned int size = skb->len;
3044 if (unlikely(size < len)) {
3046 if (__skb_pad(skb, len, free_on_error))
3048 __skb_put(skb, len);
3054 * skb_put_padto - increase size and pad an skbuff up to a minimal size
3055 * @skb: buffer to pad
3056 * @len: minimal length
3058 * Pads up a buffer to ensure the trailing bytes exist and are
3059 * blanked. If the buffer already contains sufficient data it
3060 * is untouched. Otherwise it is extended. Returns zero on
3061 * success. The skb is freed on error.
3063 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
3065 return __skb_put_padto(skb, len, true);
3068 static inline int skb_add_data(struct sk_buff *skb,
3069 struct iov_iter *from, int copy)
3071 const int off = skb->len;
3073 if (skb->ip_summed == CHECKSUM_NONE) {
3075 if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy,
3077 skb->csum = csum_block_add(skb->csum, csum, off);
3080 } else if (copy_from_iter_full(skb_put(skb, copy), copy, from))
3083 __skb_trim(skb, off);
3087 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
3088 const struct page *page, int off)
3093 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
3095 return page == skb_frag_page(frag) &&
3096 off == frag->page_offset + skb_frag_size(frag);
3101 static inline int __skb_linearize(struct sk_buff *skb)
3103 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
3107 * skb_linearize - convert paged skb to linear one
3108 * @skb: buffer to linarize
3110 * If there is no free memory -ENOMEM is returned, otherwise zero
3111 * is returned and the old skb data released.
3113 static inline int skb_linearize(struct sk_buff *skb)
3115 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
3119 * skb_has_shared_frag - can any frag be overwritten
3120 * @skb: buffer to test
3122 * Return true if the skb has at least one frag that might be modified
3123 * by an external entity (as in vmsplice()/sendfile())
3125 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
3127 return skb_is_nonlinear(skb) &&
3128 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
3132 * skb_linearize_cow - make sure skb is linear and writable
3133 * @skb: buffer to process
3135 * If there is no free memory -ENOMEM is returned, otherwise zero
3136 * is returned and the old skb data released.
3138 static inline int skb_linearize_cow(struct sk_buff *skb)
3140 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
3141 __skb_linearize(skb) : 0;
3144 static __always_inline void
3145 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
3148 if (skb->ip_summed == CHECKSUM_COMPLETE)
3149 skb->csum = csum_block_sub(skb->csum,
3150 csum_partial(start, len, 0), off);
3151 else if (skb->ip_summed == CHECKSUM_PARTIAL &&
3152 skb_checksum_start_offset(skb) < 0)
3153 skb->ip_summed = CHECKSUM_NONE;
3157 * skb_postpull_rcsum - update checksum for received skb after pull
3158 * @skb: buffer to update
3159 * @start: start of data before pull
3160 * @len: length of data pulled
3162 * After doing a pull on a received packet, you need to call this to
3163 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
3164 * CHECKSUM_NONE so that it can be recomputed from scratch.
3166 static inline void skb_postpull_rcsum(struct sk_buff *skb,
3167 const void *start, unsigned int len)
3169 __skb_postpull_rcsum(skb, start, len, 0);
3172 static __always_inline void
3173 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
3176 if (skb->ip_summed == CHECKSUM_COMPLETE)
3177 skb->csum = csum_block_add(skb->csum,
3178 csum_partial(start, len, 0), off);
3182 * skb_postpush_rcsum - update checksum for received skb after push
3183 * @skb: buffer to update
3184 * @start: start of data after push
3185 * @len: length of data pushed
3187 * After doing a push on a received packet, you need to call this to
3188 * update the CHECKSUM_COMPLETE checksum.
3190 static inline void skb_postpush_rcsum(struct sk_buff *skb,
3191 const void *start, unsigned int len)
3193 __skb_postpush_rcsum(skb, start, len, 0);
3196 void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
3199 * skb_push_rcsum - push skb and update receive checksum
3200 * @skb: buffer to update
3201 * @len: length of data pulled
3203 * This function performs an skb_push on the packet and updates
3204 * the CHECKSUM_COMPLETE checksum. It should be used on
3205 * receive path processing instead of skb_push unless you know
3206 * that the checksum difference is zero (e.g., a valid IP header)
3207 * or you are setting ip_summed to CHECKSUM_NONE.
3209 static inline void *skb_push_rcsum(struct sk_buff *skb, unsigned int len)
3212 skb_postpush_rcsum(skb, skb->data, len);
3216 int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len);
3218 * pskb_trim_rcsum - trim received skb and update checksum
3219 * @skb: buffer to trim
3222 * This is exactly the same as pskb_trim except that it ensures the
3223 * checksum of received packets are still valid after the operation.
3226 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
3228 if (likely(len >= skb->len))
3230 return pskb_trim_rcsum_slow(skb, len);
3233 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
3235 if (skb->ip_summed == CHECKSUM_COMPLETE)
3236 skb->ip_summed = CHECKSUM_NONE;
3237 __skb_trim(skb, len);
3241 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
3243 if (skb->ip_summed == CHECKSUM_COMPLETE)
3244 skb->ip_summed = CHECKSUM_NONE;
3245 return __skb_grow(skb, len);
3248 #define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode)
3249 #define skb_rb_first(root) rb_to_skb(rb_first(root))
3250 #define skb_rb_last(root) rb_to_skb(rb_last(root))
3251 #define skb_rb_next(skb) rb_to_skb(rb_next(&(skb)->rbnode))
3252 #define skb_rb_prev(skb) rb_to_skb(rb_prev(&(skb)->rbnode))
3254 #define skb_queue_walk(queue, skb) \
3255 for (skb = (queue)->next; \
3256 skb != (struct sk_buff *)(queue); \
3259 #define skb_queue_walk_safe(queue, skb, tmp) \
3260 for (skb = (queue)->next, tmp = skb->next; \
3261 skb != (struct sk_buff *)(queue); \
3262 skb = tmp, tmp = skb->next)
3264 #define skb_queue_walk_from(queue, skb) \
3265 for (; skb != (struct sk_buff *)(queue); \
3268 #define skb_rbtree_walk(skb, root) \
3269 for (skb = skb_rb_first(root); skb != NULL; \
3270 skb = skb_rb_next(skb))
3272 #define skb_rbtree_walk_from(skb) \
3273 for (; skb != NULL; \
3274 skb = skb_rb_next(skb))
3276 #define skb_rbtree_walk_from_safe(skb, tmp) \
3277 for (; tmp = skb ? skb_rb_next(skb) : NULL, (skb != NULL); \
3280 #define skb_queue_walk_from_safe(queue, skb, tmp) \
3281 for (tmp = skb->next; \
3282 skb != (struct sk_buff *)(queue); \
3283 skb = tmp, tmp = skb->next)
3285 #define skb_queue_reverse_walk(queue, skb) \
3286 for (skb = (queue)->prev; \
3287 skb != (struct sk_buff *)(queue); \
3290 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
3291 for (skb = (queue)->prev, tmp = skb->prev; \
3292 skb != (struct sk_buff *)(queue); \
3293 skb = tmp, tmp = skb->prev)
3295 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
3296 for (tmp = skb->prev; \
3297 skb != (struct sk_buff *)(queue); \
3298 skb = tmp, tmp = skb->prev)
3300 static inline bool skb_has_frag_list(const struct sk_buff *skb)
3302 return skb_shinfo(skb)->frag_list != NULL;
3305 static inline void skb_frag_list_init(struct sk_buff *skb)
3307 skb_shinfo(skb)->frag_list = NULL;
3310 #define skb_walk_frags(skb, iter) \
3311 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3314 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
3315 const struct sk_buff *skb);
3316 struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
3317 struct sk_buff_head *queue,
3319 void (*destructor)(struct sock *sk,
3320 struct sk_buff *skb),
3321 int *peeked, int *off, int *err,
3322 struct sk_buff **last);
3323 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
3324 void (*destructor)(struct sock *sk,
3325 struct sk_buff *skb),
3326 int *peeked, int *off, int *err,
3327 struct sk_buff **last);
3328 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
3329 void (*destructor)(struct sock *sk,
3330 struct sk_buff *skb),
3331 int *peeked, int *off, int *err);
3332 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
3334 __poll_t datagram_poll(struct file *file, struct socket *sock,
3335 struct poll_table_struct *wait);
3336 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
3337 struct iov_iter *to, int size);
3338 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
3339 struct msghdr *msg, int size)
3341 return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
3343 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
3344 struct msghdr *msg);
3345 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
3346 struct iov_iter *from, int len);
3347 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
3348 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
3349 void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
3350 static inline void skb_free_datagram_locked(struct sock *sk,
3351 struct sk_buff *skb)
3353 __skb_free_datagram_locked(sk, skb, 0);
3355 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
3356 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
3357 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
3358 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
3359 int len, __wsum csum);
3360 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3361 struct pipe_inode_info *pipe, unsigned int len,
3362 unsigned int flags);
3363 int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
3365 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
3366 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
3367 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
3369 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
3370 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
3371 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
3372 bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu);
3373 bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len);
3374 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
3375 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
3376 int skb_ensure_writable(struct sk_buff *skb, int write_len);
3377 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
3378 int skb_vlan_pop(struct sk_buff *skb);
3379 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
3380 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
3383 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
3385 return copy_from_iter_full(data, len, &msg->msg_iter) ? 0 : -EFAULT;
3388 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
3390 return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3393 struct skb_checksum_ops {
3394 __wsum (*update)(const void *mem, int len, __wsum wsum);
3395 __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
3398 extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly;
3400 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3401 __wsum csum, const struct skb_checksum_ops *ops);
3402 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
3405 static inline void * __must_check
3406 __skb_header_pointer(const struct sk_buff *skb, int offset,
3407 int len, void *data, int hlen, void *buffer)
3409 if (hlen - offset >= len)
3410 return data + offset;
3413 skb_copy_bits(skb, offset, buffer, len) < 0)
3419 static inline void * __must_check
3420 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
3422 return __skb_header_pointer(skb, offset, len, skb->data,
3423 skb_headlen(skb), buffer);
3427 * skb_needs_linearize - check if we need to linearize a given skb
3428 * depending on the given device features.
3429 * @skb: socket buffer to check
3430 * @features: net device features
3432 * Returns true if either:
3433 * 1. skb has frag_list and the device doesn't support FRAGLIST, or
3434 * 2. skb is fragmented and the device does not support SG.
3436 static inline bool skb_needs_linearize(struct sk_buff *skb,
3437 netdev_features_t features)
3439 return skb_is_nonlinear(skb) &&
3440 ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3441 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3444 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3446 const unsigned int len)
3448 memcpy(to, skb->data, len);
3451 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3452 const int offset, void *to,
3453 const unsigned int len)
3455 memcpy(to, skb->data + offset, len);
3458 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3460 const unsigned int len)
3462 memcpy(skb->data, from, len);
3465 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3468 const unsigned int len)
3470 memcpy(skb->data + offset, from, len);
3473 void skb_init(void);
3475 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3481 * skb_get_timestamp - get timestamp from a skb
3482 * @skb: skb to get stamp from
3483 * @stamp: pointer to struct timeval to store stamp in
3485 * Timestamps are stored in the skb as offsets to a base timestamp.
3486 * This function converts the offset back to a struct timeval and stores
3489 static inline void skb_get_timestamp(const struct sk_buff *skb,
3490 struct timeval *stamp)
3492 *stamp = ktime_to_timeval(skb->tstamp);
3495 static inline void skb_get_timestampns(const struct sk_buff *skb,
3496 struct timespec *stamp)
3498 *stamp = ktime_to_timespec(skb->tstamp);
3501 static inline void __net_timestamp(struct sk_buff *skb)
3503 skb->tstamp = ktime_get_real();
3506 static inline ktime_t net_timedelta(ktime_t t)
3508 return ktime_sub(ktime_get_real(), t);
3511 static inline ktime_t net_invalid_timestamp(void)
3516 static inline u8 skb_metadata_len(const struct sk_buff *skb)
3518 return skb_shinfo(skb)->meta_len;
3521 static inline void *skb_metadata_end(const struct sk_buff *skb)
3523 return skb_mac_header(skb);
3526 static inline bool __skb_metadata_differs(const struct sk_buff *skb_a,
3527 const struct sk_buff *skb_b,
3530 const void *a = skb_metadata_end(skb_a);
3531 const void *b = skb_metadata_end(skb_b);
3532 /* Using more efficient varaiant than plain call to memcmp(). */
3533 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
3537 #define __it(x, op) (x -= sizeof(u##op))
3538 #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op))
3539 case 32: diffs |= __it_diff(a, b, 64);
3541 case 24: diffs |= __it_diff(a, b, 64);
3543 case 16: diffs |= __it_diff(a, b, 64);
3545 case 8: diffs |= __it_diff(a, b, 64);
3547 case 28: diffs |= __it_diff(a, b, 64);
3549 case 20: diffs |= __it_diff(a, b, 64);
3551 case 12: diffs |= __it_diff(a, b, 64);
3553 case 4: diffs |= __it_diff(a, b, 32);
3558 return memcmp(a - meta_len, b - meta_len, meta_len);
3562 static inline bool skb_metadata_differs(const struct sk_buff *skb_a,
3563 const struct sk_buff *skb_b)
3565 u8 len_a = skb_metadata_len(skb_a);
3566 u8 len_b = skb_metadata_len(skb_b);
3568 if (!(len_a | len_b))
3571 return len_a != len_b ?
3572 true : __skb_metadata_differs(skb_a, skb_b, len_a);
3575 static inline void skb_metadata_set(struct sk_buff *skb, u8 meta_len)
3577 skb_shinfo(skb)->meta_len = meta_len;
3580 static inline void skb_metadata_clear(struct sk_buff *skb)
3582 skb_metadata_set(skb, 0);
3585 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3587 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3589 void skb_clone_tx_timestamp(struct sk_buff *skb);
3590 bool skb_defer_rx_timestamp(struct sk_buff *skb);
3592 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3594 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3598 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3603 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3606 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3608 * PHY drivers may accept clones of transmitted packets for
3609 * timestamping via their phy_driver.txtstamp method. These drivers
3610 * must call this function to return the skb back to the stack with a
3613 * @skb: clone of the the original outgoing packet
3614 * @hwtstamps: hardware time stamps
3617 void skb_complete_tx_timestamp(struct sk_buff *skb,
3618 struct skb_shared_hwtstamps *hwtstamps);
3620 void __skb_tstamp_tx(struct sk_buff *orig_skb,
3621 struct skb_shared_hwtstamps *hwtstamps,
3622 struct sock *sk, int tstype);
3625 * skb_tstamp_tx - queue clone of skb with send time stamps
3626 * @orig_skb: the original outgoing packet
3627 * @hwtstamps: hardware time stamps, may be NULL if not available
3629 * If the skb has a socket associated, then this function clones the
3630 * skb (thus sharing the actual data and optional structures), stores
3631 * the optional hardware time stamping information (if non NULL) or
3632 * generates a software time stamp (otherwise), then queues the clone
3633 * to the error queue of the socket. Errors are silently ignored.
3635 void skb_tstamp_tx(struct sk_buff *orig_skb,
3636 struct skb_shared_hwtstamps *hwtstamps);
3639 * skb_tx_timestamp() - Driver hook for transmit timestamping
3641 * Ethernet MAC Drivers should call this function in their hard_xmit()
3642 * function immediately before giving the sk_buff to the MAC hardware.
3644 * Specifically, one should make absolutely sure that this function is
3645 * called before TX completion of this packet can trigger. Otherwise
3646 * the packet could potentially already be freed.
3648 * @skb: A socket buffer.
3650 static inline void skb_tx_timestamp(struct sk_buff *skb)
3652 skb_clone_tx_timestamp(skb);
3653 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
3654 skb_tstamp_tx(skb, NULL);
3658 * skb_complete_wifi_ack - deliver skb with wifi status
3660 * @skb: the original outgoing packet
3661 * @acked: ack status
3664 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3666 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3667 __sum16 __skb_checksum_complete(struct sk_buff *skb);
3669 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3671 return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3673 (skb->ip_summed == CHECKSUM_PARTIAL &&
3674 skb_checksum_start_offset(skb) >= 0));
3678 * skb_checksum_complete - Calculate checksum of an entire packet
3679 * @skb: packet to process
3681 * This function calculates the checksum over the entire packet plus
3682 * the value of skb->csum. The latter can be used to supply the
3683 * checksum of a pseudo header as used by TCP/UDP. It returns the
3686 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
3687 * this function can be used to verify that checksum on received
3688 * packets. In that case the function should return zero if the
3689 * checksum is correct. In particular, this function will return zero
3690 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3691 * hardware has already verified the correctness of the checksum.
3693 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3695 return skb_csum_unnecessary(skb) ?
3696 0 : __skb_checksum_complete(skb);
3699 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3701 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3702 if (skb->csum_level == 0)
3703 skb->ip_summed = CHECKSUM_NONE;
3709 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3711 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3712 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3714 } else if (skb->ip_summed == CHECKSUM_NONE) {
3715 skb->ip_summed = CHECKSUM_UNNECESSARY;
3716 skb->csum_level = 0;
3720 /* Check if we need to perform checksum complete validation.
3722 * Returns true if checksum complete is needed, false otherwise
3723 * (either checksum is unnecessary or zero checksum is allowed).
3725 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3729 if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3730 skb->csum_valid = 1;
3731 __skb_decr_checksum_unnecessary(skb);
3738 /* For small packets <= CHECKSUM_BREAK perform checksum complete directly
3741 #define CHECKSUM_BREAK 76
3743 /* Unset checksum-complete
3745 * Unset checksum complete can be done when packet is being modified
3746 * (uncompressed for instance) and checksum-complete value is
3749 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3751 if (skb->ip_summed == CHECKSUM_COMPLETE)
3752 skb->ip_summed = CHECKSUM_NONE;
3755 /* Validate (init) checksum based on checksum complete.
3758 * 0: checksum is validated or try to in skb_checksum_complete. In the latter
3759 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3760 * checksum is stored in skb->csum for use in __skb_checksum_complete
3761 * non-zero: value of invalid checksum
3764 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3768 if (skb->ip_summed == CHECKSUM_COMPLETE) {
3769 if (!csum_fold(csum_add(psum, skb->csum))) {
3770 skb->csum_valid = 1;
3777 if (complete || skb->len <= CHECKSUM_BREAK) {
3780 csum = __skb_checksum_complete(skb);
3781 skb->csum_valid = !csum;
3788 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3793 /* Perform checksum validate (init). Note that this is a macro since we only
3794 * want to calculate the pseudo header which is an input function if necessary.
3795 * First we try to validate without any computation (checksum unnecessary) and
3796 * then calculate based on checksum complete calling the function to compute
3800 * 0: checksum is validated or try to in skb_checksum_complete
3801 * non-zero: value of invalid checksum
3803 #define __skb_checksum_validate(skb, proto, complete, \
3804 zero_okay, check, compute_pseudo) \
3806 __sum16 __ret = 0; \
3807 skb->csum_valid = 0; \
3808 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
3809 __ret = __skb_checksum_validate_complete(skb, \
3810 complete, compute_pseudo(skb, proto)); \
3814 #define skb_checksum_init(skb, proto, compute_pseudo) \
3815 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3817 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3818 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3820 #define skb_checksum_validate(skb, proto, compute_pseudo) \
3821 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3823 #define skb_checksum_validate_zero_check(skb, proto, check, \
3825 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3827 #define skb_checksum_simple_validate(skb) \
3828 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3830 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3832 return (skb->ip_summed == CHECKSUM_NONE && skb->csum_valid);
3835 static inline void __skb_checksum_convert(struct sk_buff *skb,
3836 __sum16 check, __wsum pseudo)
3838 skb->csum = ~pseudo;
3839 skb->ip_summed = CHECKSUM_COMPLETE;
3842 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo) \
3844 if (__skb_checksum_convert_check(skb)) \
3845 __skb_checksum_convert(skb, check, \
3846 compute_pseudo(skb, proto)); \
3849 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3850 u16 start, u16 offset)
3852 skb->ip_summed = CHECKSUM_PARTIAL;
3853 skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3854 skb->csum_offset = offset - start;
3857 /* Update skbuf and packet to reflect the remote checksum offload operation.
3858 * When called, ptr indicates the starting point for skb->csum when
3859 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3860 * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3862 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3863 int start, int offset, bool nopartial)
3868 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3872 if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3873 __skb_checksum_complete(skb);
3874 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3877 delta = remcsum_adjust(ptr, skb->csum, start, offset);
3879 /* Adjust skb->csum since we changed the packet */
3880 skb->csum = csum_add(skb->csum, delta);
3883 static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb)
3885 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3886 return (void *)(skb->_nfct & SKB_NFCT_PTRMASK);
3892 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3893 void nf_conntrack_destroy(struct nf_conntrack *nfct);
3894 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3896 if (nfct && atomic_dec_and_test(&nfct->use))
3897 nf_conntrack_destroy(nfct);
3899 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3902 atomic_inc(&nfct->use);
3906 #ifdef CONFIG_SKB_EXTENSIONS
3908 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3911 SKB_EXT_NUM, /* must be last */
3915 * struct skb_ext - sk_buff extensions
3916 * @refcnt: 1 on allocation, deallocated on 0
3917 * @offset: offset to add to @data to obtain extension address
3918 * @chunks: size currently allocated, stored in SKB_EXT_ALIGN_SHIFT units
3919 * @data: start of extension data, variable sized
3921 * Note: offsets/lengths are stored in chunks of 8 bytes, this allows
3922 * to use 'u8' types while allowing up to 2kb worth of extension data.
3926 u8 offset[SKB_EXT_NUM]; /* in chunks of 8 bytes */
3927 u8 chunks; /* same */
3928 char data[0] __aligned(8);
3931 void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id);
3932 void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id);
3933 void __skb_ext_put(struct skb_ext *ext);
3935 static inline void skb_ext_put(struct sk_buff *skb)
3937 if (skb->active_extensions)
3938 __skb_ext_put(skb->extensions);
3941 static inline void skb_ext_get(struct sk_buff *skb)
3943 if (skb->active_extensions) {
3944 struct skb_ext *ext = skb->extensions;
3947 refcount_inc(&ext->refcnt);
3951 static inline void __skb_ext_copy(struct sk_buff *dst,
3952 const struct sk_buff *src)
3954 dst->active_extensions = src->active_extensions;
3956 if (src->active_extensions) {
3957 struct skb_ext *ext = src->extensions;
3959 refcount_inc(&ext->refcnt);
3960 dst->extensions = ext;
3964 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src)
3967 __skb_ext_copy(dst, src);
3970 static inline bool __skb_ext_exist(const struct skb_ext *ext, enum skb_ext_id i)
3972 return !!ext->offset[i];
3975 static inline bool skb_ext_exist(const struct sk_buff *skb, enum skb_ext_id id)
3977 return skb->active_extensions & (1 << id);
3980 static inline void skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
3982 if (skb_ext_exist(skb, id))
3983 __skb_ext_del(skb, id);
3986 static inline void *skb_ext_find(const struct sk_buff *skb, enum skb_ext_id id)
3988 if (skb_ext_exist(skb, id)) {
3989 struct skb_ext *ext = skb->extensions;
3991 return (void *)ext + (ext->offset[id] << 3);
3997 static inline void skb_ext_put(struct sk_buff *skb) {}
3998 static inline void skb_ext_get(struct sk_buff *skb) {}
3999 static inline void skb_ext_del(struct sk_buff *skb, int unused) {}
4000 static inline void __skb_ext_copy(struct sk_buff *d, const struct sk_buff *s) {}
4001 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *s) {}
4002 #endif /* CONFIG_SKB_EXTENSIONS */
4004 static inline void nf_reset(struct sk_buff *skb)
4006 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4007 nf_conntrack_put(skb_nfct(skb));
4010 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4011 skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
4015 static inline void nf_reset_trace(struct sk_buff *skb)
4017 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
4022 static inline void ipvs_reset(struct sk_buff *skb)
4024 #if IS_ENABLED(CONFIG_IP_VS)
4025 skb->ipvs_property = 0;
4029 /* Note: This doesn't put any conntrack info in dst. */
4030 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
4033 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4034 dst->_nfct = src->_nfct;
4035 nf_conntrack_get(skb_nfct(src));
4037 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
4039 dst->nf_trace = src->nf_trace;
4043 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
4045 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4046 nf_conntrack_put(skb_nfct(dst));
4048 __nf_copy(dst, src, true);
4051 #ifdef CONFIG_NETWORK_SECMARK
4052 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
4054 to->secmark = from->secmark;
4057 static inline void skb_init_secmark(struct sk_buff *skb)
4062 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
4065 static inline void skb_init_secmark(struct sk_buff *skb)
4069 static inline int secpath_exists(const struct sk_buff *skb)
4072 return skb->sp != NULL;
4078 static inline bool skb_irq_freeable(const struct sk_buff *skb)
4080 return !skb->destructor &&
4081 !secpath_exists(skb) &&
4083 !skb->_skb_refdst &&
4084 !skb_has_frag_list(skb);
4087 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
4089 skb->queue_mapping = queue_mapping;
4092 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
4094 return skb->queue_mapping;
4097 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
4099 to->queue_mapping = from->queue_mapping;
4102 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
4104 skb->queue_mapping = rx_queue + 1;
4107 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
4109 return skb->queue_mapping - 1;
4112 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
4114 return skb->queue_mapping != 0;
4117 static inline void skb_set_dst_pending_confirm(struct sk_buff *skb, u32 val)
4119 skb->dst_pending_confirm = val;
4122 static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb)
4124 return skb->dst_pending_confirm != 0;
4127 static inline struct sec_path *skb_sec_path(const struct sk_buff *skb)
4136 /* Keeps track of mac header offset relative to skb->head.
4137 * It is useful for TSO of Tunneling protocol. e.g. GRE.
4138 * For non-tunnel skb it points to skb_mac_header() and for
4139 * tunnel skb it points to outer mac header.
4140 * Keeps track of level of encapsulation of network headers.
4151 #define SKB_SGO_CB_OFFSET 32
4152 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
4154 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
4156 return (skb_mac_header(inner_skb) - inner_skb->head) -
4157 SKB_GSO_CB(inner_skb)->mac_offset;
4160 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
4162 int new_headroom, headroom;
4165 headroom = skb_headroom(skb);
4166 ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
4170 new_headroom = skb_headroom(skb);
4171 SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
4175 static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
4177 /* Do not update partial checksums if remote checksum is enabled. */
4178 if (skb->remcsum_offload)
4181 SKB_GSO_CB(skb)->csum = res;
4182 SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
4185 /* Compute the checksum for a gso segment. First compute the checksum value
4186 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
4187 * then add in skb->csum (checksum from csum_start to end of packet).
4188 * skb->csum and csum_start are then updated to reflect the checksum of the
4189 * resultant packet starting from the transport header-- the resultant checksum
4190 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
4193 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
4195 unsigned char *csum_start = skb_transport_header(skb);
4196 int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
4197 __wsum partial = SKB_GSO_CB(skb)->csum;
4199 SKB_GSO_CB(skb)->csum = res;
4200 SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
4202 return csum_fold(csum_partial(csum_start, plen, partial));
4205 static inline bool skb_is_gso(const struct sk_buff *skb)
4207 return skb_shinfo(skb)->gso_size;
4210 /* Note: Should be called only if skb_is_gso(skb) is true */
4211 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
4213 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
4216 /* Note: Should be called only if skb_is_gso(skb) is true */
4217 static inline bool skb_is_gso_sctp(const struct sk_buff *skb)
4219 return skb_shinfo(skb)->gso_type & SKB_GSO_SCTP;
4222 static inline void skb_gso_reset(struct sk_buff *skb)
4224 skb_shinfo(skb)->gso_size = 0;
4225 skb_shinfo(skb)->gso_segs = 0;
4226 skb_shinfo(skb)->gso_type = 0;
4229 static inline void skb_increase_gso_size(struct skb_shared_info *shinfo,
4232 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
4234 shinfo->gso_size += increment;
4237 static inline void skb_decrease_gso_size(struct skb_shared_info *shinfo,
4240 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
4242 shinfo->gso_size -= decrement;
4245 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
4247 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
4249 /* LRO sets gso_size but not gso_type, whereas if GSO is really
4250 * wanted then gso_type will be set. */
4251 const struct skb_shared_info *shinfo = skb_shinfo(skb);
4253 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
4254 unlikely(shinfo->gso_type == 0)) {
4255 __skb_warn_lro_forwarding(skb);
4261 static inline void skb_forward_csum(struct sk_buff *skb)
4263 /* Unfortunately we don't support this one. Any brave souls? */
4264 if (skb->ip_summed == CHECKSUM_COMPLETE)
4265 skb->ip_summed = CHECKSUM_NONE;
4269 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
4270 * @skb: skb to check
4272 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
4273 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
4274 * use this helper, to document places where we make this assertion.
4276 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
4279 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
4283 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
4285 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
4286 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
4287 unsigned int transport_len,
4288 __sum16(*skb_chkf)(struct sk_buff *skb));
4291 * skb_head_is_locked - Determine if the skb->head is locked down
4292 * @skb: skb to check
4294 * The head on skbs build around a head frag can be removed if they are
4295 * not cloned. This function returns true if the skb head is locked down
4296 * due to either being allocated via kmalloc, or by being a clone with
4297 * multiple references to the head.
4299 static inline bool skb_head_is_locked(const struct sk_buff *skb)
4301 return !skb->head_frag || skb_cloned(skb);
4304 /* Local Checksum Offload.
4305 * Compute outer checksum based on the assumption that the
4306 * inner checksum will be offloaded later.
4307 * See Documentation/networking/checksum-offloads.txt for
4308 * explanation of how this works.
4309 * Fill in outer checksum adjustment (e.g. with sum of outer
4310 * pseudo-header) before calling.
4311 * Also ensure that inner checksum is in linear data area.
4313 static inline __wsum lco_csum(struct sk_buff *skb)
4315 unsigned char *csum_start = skb_checksum_start(skb);
4316 unsigned char *l4_hdr = skb_transport_header(skb);
4319 /* Start with complement of inner checksum adjustment */
4320 partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
4323 /* Add in checksum of our headers (incl. outer checksum
4324 * adjustment filled in by caller) and return result.
4326 return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
4329 #endif /* __KERNEL__ */
4330 #endif /* _LINUX_SKBUFF_H */