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)
331 * skb_frag_size - Returns the size of a skb fragment
332 * @frag: skb fragment
334 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
340 * skb_frag_size_set - Sets the size of a skb fragment
341 * @frag: skb fragment
342 * @size: size of fragment
344 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
350 * skb_frag_size_add - Incrementes the size of a skb fragment by %delta
351 * @frag: skb fragment
352 * @delta: value to add
354 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
360 * skb_frag_size_sub - Decrements the size of a skb fragment by %delta
361 * @frag: skb fragment
362 * @delta: value to subtract
364 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
370 * skb_frag_must_loop - Test if %p is a high memory page
371 * @p: fragment's page
373 static inline bool skb_frag_must_loop(struct page *p)
375 #if defined(CONFIG_HIGHMEM)
383 * skb_frag_foreach_page - loop over pages in a fragment
385 * @f: skb frag to operate on
386 * @f_off: offset from start of f->page.p
387 * @f_len: length from f_off to loop over
388 * @p: (temp var) current page
389 * @p_off: (temp var) offset from start of current page,
390 * non-zero only on first page.
391 * @p_len: (temp var) length in current page,
392 * < PAGE_SIZE only on first and last page.
393 * @copied: (temp var) length so far, excluding current p_len.
395 * A fragment can hold a compound page, in which case per-page
396 * operations, notably kmap_atomic, must be called for each
399 #define skb_frag_foreach_page(f, f_off, f_len, p, p_off, p_len, copied) \
400 for (p = skb_frag_page(f) + ((f_off) >> PAGE_SHIFT), \
401 p_off = (f_off) & (PAGE_SIZE - 1), \
402 p_len = skb_frag_must_loop(p) ? \
403 min_t(u32, f_len, PAGE_SIZE - p_off) : f_len, \
406 copied += p_len, p++, p_off = 0, \
407 p_len = min_t(u32, f_len - copied, PAGE_SIZE)) \
409 #define HAVE_HW_TIME_STAMP
412 * struct skb_shared_hwtstamps - hardware time stamps
413 * @hwtstamp: hardware time stamp transformed into duration
414 * since arbitrary point in time
416 * Software time stamps generated by ktime_get_real() are stored in
419 * hwtstamps can only be compared against other hwtstamps from
422 * This structure is attached to packets as part of the
423 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
425 struct skb_shared_hwtstamps {
429 /* Definitions for tx_flags in struct skb_shared_info */
431 /* generate hardware time stamp */
432 SKBTX_HW_TSTAMP = 1 << 0,
434 /* generate software time stamp when queueing packet to NIC */
435 SKBTX_SW_TSTAMP = 1 << 1,
437 /* device driver is going to provide hardware time stamp */
438 SKBTX_IN_PROGRESS = 1 << 2,
440 /* device driver supports TX zero-copy buffers */
441 SKBTX_DEV_ZEROCOPY = 1 << 3,
443 /* generate wifi status information (where possible) */
444 SKBTX_WIFI_STATUS = 1 << 4,
446 /* This indicates at least one fragment might be overwritten
447 * (as in vmsplice(), sendfile() ...)
448 * If we need to compute a TX checksum, we'll need to copy
449 * all frags to avoid possible bad checksum
451 SKBTX_SHARED_FRAG = 1 << 5,
453 /* generate software time stamp when entering packet scheduling */
454 SKBTX_SCHED_TSTAMP = 1 << 6,
457 #define SKBTX_ZEROCOPY_FRAG (SKBTX_DEV_ZEROCOPY | SKBTX_SHARED_FRAG)
458 #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
460 #define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
463 * The callback notifies userspace to release buffers when skb DMA is done in
464 * lower device, the skb last reference should be 0 when calling this.
465 * The zerocopy_success argument is true if zero copy transmit occurred,
466 * false on data copy or out of memory error caused by data copy attempt.
467 * The ctx field is used to track device context.
468 * The desc field is used to track userspace buffer index.
471 void (*callback)(struct ubuf_info *, bool zerocopy_success);
487 struct user_struct *user;
492 #define skb_uarg(SKB) ((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg))
494 int mm_account_pinned_pages(struct mmpin *mmp, size_t size);
495 void mm_unaccount_pinned_pages(struct mmpin *mmp);
497 struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size);
498 struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size,
499 struct ubuf_info *uarg);
501 static inline void sock_zerocopy_get(struct ubuf_info *uarg)
503 refcount_inc(&uarg->refcnt);
506 void sock_zerocopy_put(struct ubuf_info *uarg);
507 void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
509 void sock_zerocopy_callback(struct ubuf_info *uarg, bool success);
511 int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len);
512 int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
513 struct msghdr *msg, int len,
514 struct ubuf_info *uarg);
516 /* This data is invariant across clones and lives at
517 * the end of the header data, ie. at skb->end.
519 struct skb_shared_info {
524 unsigned short gso_size;
525 /* Warning: this field is not always filled in (UFO)! */
526 unsigned short gso_segs;
527 struct sk_buff *frag_list;
528 struct skb_shared_hwtstamps hwtstamps;
529 unsigned int gso_type;
533 * Warning : all fields before dataref are cleared in __alloc_skb()
537 /* Intermediate layers must ensure that destructor_arg
538 * remains valid until skb destructor */
539 void * destructor_arg;
541 /* must be last field, see pskb_expand_head() */
542 skb_frag_t frags[MAX_SKB_FRAGS];
545 /* We divide dataref into two halves. The higher 16 bits hold references
546 * to the payload part of skb->data. The lower 16 bits hold references to
547 * the entire skb->data. A clone of a headerless skb holds the length of
548 * the header in skb->hdr_len.
550 * All users must obey the rule that the skb->data reference count must be
551 * greater than or equal to the payload reference count.
553 * Holding a reference to the payload part means that the user does not
554 * care about modifications to the header part of skb->data.
556 #define SKB_DATAREF_SHIFT 16
557 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
561 SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
562 SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */
563 SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */
567 SKB_GSO_TCPV4 = 1 << 0,
569 /* This indicates the skb is from an untrusted source. */
570 SKB_GSO_DODGY = 1 << 1,
572 /* This indicates the tcp segment has CWR set. */
573 SKB_GSO_TCP_ECN = 1 << 2,
575 SKB_GSO_TCP_FIXEDID = 1 << 3,
577 SKB_GSO_TCPV6 = 1 << 4,
579 SKB_GSO_FCOE = 1 << 5,
581 SKB_GSO_GRE = 1 << 6,
583 SKB_GSO_GRE_CSUM = 1 << 7,
585 SKB_GSO_IPXIP4 = 1 << 8,
587 SKB_GSO_IPXIP6 = 1 << 9,
589 SKB_GSO_UDP_TUNNEL = 1 << 10,
591 SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
593 SKB_GSO_PARTIAL = 1 << 12,
595 SKB_GSO_TUNNEL_REMCSUM = 1 << 13,
597 SKB_GSO_SCTP = 1 << 14,
599 SKB_GSO_ESP = 1 << 15,
601 SKB_GSO_UDP = 1 << 16,
603 SKB_GSO_UDP_L4 = 1 << 17,
606 #if BITS_PER_LONG > 32
607 #define NET_SKBUFF_DATA_USES_OFFSET 1
610 #ifdef NET_SKBUFF_DATA_USES_OFFSET
611 typedef unsigned int sk_buff_data_t;
613 typedef unsigned char *sk_buff_data_t;
617 * struct sk_buff - socket buffer
618 * @next: Next buffer in list
619 * @prev: Previous buffer in list
620 * @tstamp: Time we arrived/left
621 * @rbnode: RB tree node, alternative to next/prev for netem/tcp
622 * @sk: Socket we are owned by
623 * @dev: Device we arrived on/are leaving by
624 * @cb: Control buffer. Free for use by every layer. Put private vars here
625 * @_skb_refdst: destination entry (with norefcount bit)
626 * @sp: the security path, used for xfrm
627 * @len: Length of actual data
628 * @data_len: Data length
629 * @mac_len: Length of link layer header
630 * @hdr_len: writable header length of cloned skb
631 * @csum: Checksum (must include start/offset pair)
632 * @csum_start: Offset from skb->head where checksumming should start
633 * @csum_offset: Offset from csum_start where checksum should be stored
634 * @priority: Packet queueing priority
635 * @ignore_df: allow local fragmentation
636 * @cloned: Head may be cloned (check refcnt to be sure)
637 * @ip_summed: Driver fed us an IP checksum
638 * @nohdr: Payload reference only, must not modify header
639 * @pkt_type: Packet class
640 * @fclone: skbuff clone status
641 * @ipvs_property: skbuff is owned by ipvs
642 * @offload_fwd_mark: Packet was L2-forwarded in hardware
643 * @offload_l3_fwd_mark: Packet was L3-forwarded in hardware
644 * @tc_skip_classify: do not classify packet. set by IFB device
645 * @tc_at_ingress: used within tc_classify to distinguish in/egress
646 * @tc_redirected: packet was redirected by a tc action
647 * @tc_from_ingress: if tc_redirected, tc_at_ingress at time of redirect
648 * @peeked: this packet has been seen already, so stats have been
649 * done for it, don't do them again
650 * @nf_trace: netfilter packet trace flag
651 * @protocol: Packet protocol from driver
652 * @destructor: Destruct function
653 * @tcp_tsorted_anchor: list structure for TCP (tp->tsorted_sent_queue)
654 * @_nfct: Associated connection, if any (with nfctinfo bits)
655 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
656 * @skb_iif: ifindex of device we arrived on
657 * @tc_index: Traffic control index
658 * @hash: the packet hash
659 * @queue_mapping: Queue mapping for multiqueue devices
660 * @pfmemalloc: skbuff was allocated from PFMEMALLOC reserves
661 * @active_extensions: active extensions (skb_ext_id types)
662 * @ndisc_nodetype: router type (from link layer)
663 * @ooo_okay: allow the mapping of a socket to a queue to be changed
664 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport
666 * @sw_hash: indicates hash was computed in software stack
667 * @wifi_acked_valid: wifi_acked was set
668 * @wifi_acked: whether frame was acked on wifi or not
669 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
670 * @csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL
671 * @dst_pending_confirm: need to confirm neighbour
672 * @decrypted: Decrypted SKB
673 * @napi_id: id of the NAPI struct this skb came from
674 * @secmark: security marking
675 * @mark: Generic packet mark
676 * @vlan_proto: vlan encapsulation protocol
677 * @vlan_tci: vlan tag control information
678 * @inner_protocol: Protocol (encapsulation)
679 * @inner_transport_header: Inner transport layer header (encapsulation)
680 * @inner_network_header: Network layer header (encapsulation)
681 * @inner_mac_header: Link layer header (encapsulation)
682 * @transport_header: Transport layer header
683 * @network_header: Network layer header
684 * @mac_header: Link layer header
685 * @tail: Tail pointer
687 * @head: Head of buffer
688 * @data: Data head pointer
689 * @truesize: Buffer size
690 * @users: User count - see {datagram,tcp}.c
691 * @extensions: allocated extensions, valid if active_extensions is nonzero
697 /* These two members must be first. */
698 struct sk_buff *next;
699 struct sk_buff *prev;
702 struct net_device *dev;
703 /* Some protocols might use this space to store information,
704 * while device pointer would be NULL.
705 * UDP receive path is one user.
707 unsigned long dev_scratch;
710 struct rb_node rbnode; /* used in netem, ip4 defrag, and tcp stack */
711 struct list_head list;
716 int ip_defrag_offset;
721 u64 skb_mstamp_ns; /* earliest departure time */
724 * This is the control buffer. It is free to use for every
725 * layer. Please put your private variables there. If you
726 * want to keep them across layers you have to do a skb_clone()
727 * first. This is owned by whoever has the skb queued ATM.
729 char cb[48] __aligned(8);
733 unsigned long _skb_refdst;
734 void (*destructor)(struct sk_buff *skb);
736 struct list_head tcp_tsorted_anchor;
739 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
747 /* Following fields are _not_ copied in __copy_skb_header()
748 * Note that queue_mapping is here mostly to fill a hole.
752 /* if you move cloned around you also must adapt those constants */
753 #ifdef __BIG_ENDIAN_BITFIELD
754 #define CLONED_MASK (1 << 7)
756 #define CLONED_MASK 1
758 #define CLONED_OFFSET() offsetof(struct sk_buff, __cloned_offset)
760 __u8 __cloned_offset[0];
767 #ifdef CONFIG_SKB_EXTENSIONS
768 __u8 active_extensions;
770 /* fields enclosed in headers_start/headers_end are copied
771 * using a single memcpy() in __copy_skb_header()
774 __u32 headers_start[0];
777 /* if you move pkt_type around you also must adapt those constants */
778 #ifdef __BIG_ENDIAN_BITFIELD
779 #define PKT_TYPE_MAX (7 << 5)
781 #define PKT_TYPE_MAX 7
783 #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
785 __u8 __pkt_type_offset[0];
794 __u8 wifi_acked_valid:1;
797 /* Indicates the inner headers are valid in the skbuff. */
798 __u8 encapsulation:1;
799 __u8 encap_hdr_csum:1;
802 #ifdef __BIG_ENDIAN_BITFIELD
803 #define PKT_VLAN_PRESENT_BIT 7
805 #define PKT_VLAN_PRESENT_BIT 0
807 #define PKT_VLAN_PRESENT_OFFSET() offsetof(struct sk_buff, __pkt_vlan_present_offset)
808 __u8 __pkt_vlan_present_offset[0];
810 __u8 csum_complete_sw:1;
812 __u8 csum_not_inet:1;
813 __u8 dst_pending_confirm:1;
814 #ifdef CONFIG_IPV6_NDISC_NODETYPE
815 __u8 ndisc_nodetype:2;
818 __u8 ipvs_property:1;
819 __u8 inner_protocol_type:1;
820 __u8 remcsum_offload:1;
821 #ifdef CONFIG_NET_SWITCHDEV
822 __u8 offload_fwd_mark:1;
823 __u8 offload_l3_fwd_mark:1;
825 #ifdef CONFIG_NET_CLS_ACT
826 __u8 tc_skip_classify:1;
827 __u8 tc_at_ingress:1;
828 __u8 tc_redirected:1;
829 __u8 tc_from_ingress:1;
831 #ifdef CONFIG_TLS_DEVICE
835 #ifdef CONFIG_NET_SCHED
836 __u16 tc_index; /* traffic control index */
851 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
853 unsigned int napi_id;
854 unsigned int sender_cpu;
857 #ifdef CONFIG_NETWORK_SECMARK
863 __u32 reserved_tailroom;
867 __be16 inner_protocol;
871 __u16 inner_transport_header;
872 __u16 inner_network_header;
873 __u16 inner_mac_header;
876 __u16 transport_header;
877 __u16 network_header;
881 __u32 headers_end[0];
884 /* These elements must be at the end, see alloc_skb() for details. */
889 unsigned int truesize;
892 #ifdef CONFIG_SKB_EXTENSIONS
893 /* only useable after checking ->active_extensions != 0 */
894 struct skb_ext *extensions;
900 * Handling routines are only of interest to the kernel
903 #define SKB_ALLOC_FCLONE 0x01
904 #define SKB_ALLOC_RX 0x02
905 #define SKB_ALLOC_NAPI 0x04
908 * skb_pfmemalloc - Test if the skb was allocated from PFMEMALLOC reserves
911 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
913 return unlikely(skb->pfmemalloc);
917 * skb might have a dst pointer attached, refcounted or not.
918 * _skb_refdst low order bit is set if refcount was _not_ taken
920 #define SKB_DST_NOREF 1UL
921 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
923 #define SKB_NFCT_PTRMASK ~(7UL)
925 * skb_dst - returns skb dst_entry
928 * Returns skb dst_entry, regardless of reference taken or not.
930 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
932 /* If refdst was not refcounted, check we still are in a
933 * rcu_read_lock section
935 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
936 !rcu_read_lock_held() &&
937 !rcu_read_lock_bh_held());
938 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
942 * skb_dst_set - sets skb dst
946 * Sets skb dst, assuming a reference was taken on dst and should
947 * be released by skb_dst_drop()
949 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
951 skb->_skb_refdst = (unsigned long)dst;
955 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
959 * Sets skb dst, assuming a reference was not taken on dst.
960 * If dst entry is cached, we do not take reference and dst_release
961 * will be avoided by refdst_drop. If dst entry is not cached, we take
962 * reference, so that last dst_release can destroy the dst immediately.
964 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
966 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
967 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
971 * skb_dst_is_noref - Test if skb dst isn't refcounted
974 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
976 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
980 * skb_rtable - Returns the skb &rtable
983 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
985 return (struct rtable *)skb_dst(skb);
988 /* For mangling skb->pkt_type from user space side from applications
989 * such as nft, tc, etc, we only allow a conservative subset of
990 * possible pkt_types to be set.
992 static inline bool skb_pkt_type_ok(u32 ptype)
994 return ptype <= PACKET_OTHERHOST;
998 * skb_napi_id - Returns the skb's NAPI id
1001 static inline unsigned int skb_napi_id(const struct sk_buff *skb)
1003 #ifdef CONFIG_NET_RX_BUSY_POLL
1004 return skb->napi_id;
1011 * skb_unref - decrement the skb's reference count
1014 * Returns true if we can free the skb.
1016 static inline bool skb_unref(struct sk_buff *skb)
1020 if (likely(refcount_read(&skb->users) == 1))
1022 else if (likely(!refcount_dec_and_test(&skb->users)))
1028 void skb_release_head_state(struct sk_buff *skb);
1029 void kfree_skb(struct sk_buff *skb);
1030 void kfree_skb_list(struct sk_buff *segs);
1031 void skb_tx_error(struct sk_buff *skb);
1032 void consume_skb(struct sk_buff *skb);
1033 void __consume_stateless_skb(struct sk_buff *skb);
1034 void __kfree_skb(struct sk_buff *skb);
1035 extern struct kmem_cache *skbuff_head_cache;
1037 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
1038 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
1039 bool *fragstolen, int *delta_truesize);
1041 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
1043 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
1044 struct sk_buff *build_skb(void *data, unsigned int frag_size);
1045 struct sk_buff *build_skb_around(struct sk_buff *skb,
1046 void *data, unsigned int frag_size);
1049 * alloc_skb - allocate a network buffer
1050 * @size: size to allocate
1051 * @priority: allocation mask
1053 * This function is a convenient wrapper around __alloc_skb().
1055 static inline struct sk_buff *alloc_skb(unsigned int size,
1058 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
1061 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
1062 unsigned long data_len,
1067 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
1068 struct sk_buff_fclones {
1069 struct sk_buff skb1;
1071 struct sk_buff skb2;
1073 refcount_t fclone_ref;
1077 * skb_fclone_busy - check if fclone is busy
1081 * Returns true if skb is a fast clone, and its clone is not freed.
1082 * Some drivers call skb_orphan() in their ndo_start_xmit(),
1083 * so we also check that this didnt happen.
1085 static inline bool skb_fclone_busy(const struct sock *sk,
1086 const struct sk_buff *skb)
1088 const struct sk_buff_fclones *fclones;
1090 fclones = container_of(skb, struct sk_buff_fclones, skb1);
1092 return skb->fclone == SKB_FCLONE_ORIG &&
1093 refcount_read(&fclones->fclone_ref) > 1 &&
1094 fclones->skb2.sk == sk;
1098 * alloc_skb_fclone - allocate a network buffer from fclone cache
1099 * @size: size to allocate
1100 * @priority: allocation mask
1102 * This function is a convenient wrapper around __alloc_skb().
1104 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
1107 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
1110 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
1111 void skb_headers_offset_update(struct sk_buff *skb, int off);
1112 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
1113 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
1114 void skb_copy_header(struct sk_buff *new, const struct sk_buff *old);
1115 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
1116 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1117 gfp_t gfp_mask, bool fclone);
1118 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
1121 return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
1124 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
1125 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
1126 unsigned int headroom);
1127 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
1128 int newtailroom, gfp_t priority);
1129 int __must_check skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
1130 int offset, int len);
1131 int __must_check skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg,
1132 int offset, int len);
1133 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
1134 int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error);
1137 * skb_pad - zero pad the tail of an skb
1138 * @skb: buffer to pad
1139 * @pad: space to pad
1141 * Ensure that a buffer is followed by a padding area that is zero
1142 * filled. Used by network drivers which may DMA or transfer data
1143 * beyond the buffer end onto the wire.
1145 * May return error in out of memory cases. The skb is freed on error.
1147 static inline int skb_pad(struct sk_buff *skb, int pad)
1149 return __skb_pad(skb, pad, true);
1151 #define dev_kfree_skb(a) consume_skb(a)
1153 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1154 int offset, size_t size);
1156 struct skb_seq_state {
1160 __u32 stepped_offset;
1161 struct sk_buff *root_skb;
1162 struct sk_buff *cur_skb;
1166 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1167 unsigned int to, struct skb_seq_state *st);
1168 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1169 struct skb_seq_state *st);
1170 void skb_abort_seq_read(struct skb_seq_state *st);
1172 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1173 unsigned int to, struct ts_config *config);
1176 * Packet hash types specify the type of hash in skb_set_hash.
1178 * Hash types refer to the protocol layer addresses which are used to
1179 * construct a packet's hash. The hashes are used to differentiate or identify
1180 * flows of the protocol layer for the hash type. Hash types are either
1181 * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1183 * Properties of hashes:
1185 * 1) Two packets in different flows have different hash values
1186 * 2) Two packets in the same flow should have the same hash value
1188 * A hash at a higher layer is considered to be more specific. A driver should
1189 * set the most specific hash possible.
1191 * A driver cannot indicate a more specific hash than the layer at which a hash
1192 * was computed. For instance an L3 hash cannot be set as an L4 hash.
1194 * A driver may indicate a hash level which is less specific than the
1195 * actual layer the hash was computed on. For instance, a hash computed
1196 * at L4 may be considered an L3 hash. This should only be done if the
1197 * driver can't unambiguously determine that the HW computed the hash at
1198 * the higher layer. Note that the "should" in the second property above
1201 enum pkt_hash_types {
1202 PKT_HASH_TYPE_NONE, /* Undefined type */
1203 PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
1204 PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
1205 PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
1208 static inline void skb_clear_hash(struct sk_buff *skb)
1215 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1218 skb_clear_hash(skb);
1222 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1224 skb->l4_hash = is_l4;
1225 skb->sw_hash = is_sw;
1230 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1232 /* Used by drivers to set hash from HW */
1233 __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1237 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1239 __skb_set_hash(skb, hash, true, is_l4);
1242 void __skb_get_hash(struct sk_buff *skb);
1243 u32 __skb_get_hash_symmetric(const struct sk_buff *skb);
1244 u32 skb_get_poff(const struct sk_buff *skb);
1245 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1246 const struct flow_keys_basic *keys, int hlen);
1247 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1248 void *data, int hlen_proto);
1250 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1251 int thoff, u8 ip_proto)
1253 return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1256 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1257 const struct flow_dissector_key *key,
1258 unsigned int key_count);
1261 int skb_flow_dissector_prog_query(const union bpf_attr *attr,
1262 union bpf_attr __user *uattr);
1263 int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
1264 struct bpf_prog *prog);
1266 int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr);
1268 static inline int skb_flow_dissector_prog_query(const union bpf_attr *attr,
1269 union bpf_attr __user *uattr)
1274 static inline int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
1275 struct bpf_prog *prog)
1280 static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
1286 struct bpf_flow_dissector;
1287 bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
1288 __be16 proto, int nhoff, int hlen);
1290 bool __skb_flow_dissect(const struct net *net,
1291 const struct sk_buff *skb,
1292 struct flow_dissector *flow_dissector,
1293 void *target_container,
1294 void *data, __be16 proto, int nhoff, int hlen,
1295 unsigned int flags);
1297 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1298 struct flow_dissector *flow_dissector,
1299 void *target_container, unsigned int flags)
1301 return __skb_flow_dissect(NULL, skb, flow_dissector,
1302 target_container, NULL, 0, 0, 0, flags);
1305 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1306 struct flow_keys *flow,
1309 memset(flow, 0, sizeof(*flow));
1310 return __skb_flow_dissect(NULL, skb, &flow_keys_dissector,
1311 flow, NULL, 0, 0, 0, flags);
1315 skb_flow_dissect_flow_keys_basic(const struct net *net,
1316 const struct sk_buff *skb,
1317 struct flow_keys_basic *flow, void *data,
1318 __be16 proto, int nhoff, int hlen,
1321 memset(flow, 0, sizeof(*flow));
1322 return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow,
1323 data, proto, nhoff, hlen, flags);
1327 skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
1328 struct flow_dissector *flow_dissector,
1329 void *target_container);
1331 static inline __u32 skb_get_hash(struct sk_buff *skb)
1333 if (!skb->l4_hash && !skb->sw_hash)
1334 __skb_get_hash(skb);
1339 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1341 if (!skb->l4_hash && !skb->sw_hash) {
1342 struct flow_keys keys;
1343 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1345 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1351 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1353 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1358 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1360 to->hash = from->hash;
1361 to->sw_hash = from->sw_hash;
1362 to->l4_hash = from->l4_hash;
1365 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1366 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1368 return skb->head + skb->end;
1371 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1376 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1381 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1383 return skb->end - skb->head;
1388 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1390 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1392 return &skb_shinfo(skb)->hwtstamps;
1395 static inline struct ubuf_info *skb_zcopy(struct sk_buff *skb)
1397 bool is_zcopy = skb && skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY;
1399 return is_zcopy ? skb_uarg(skb) : NULL;
1402 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg,
1405 if (skb && uarg && !skb_zcopy(skb)) {
1406 if (unlikely(have_ref && *have_ref))
1409 sock_zerocopy_get(uarg);
1410 skb_shinfo(skb)->destructor_arg = uarg;
1411 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG;
1415 static inline void skb_zcopy_set_nouarg(struct sk_buff *skb, void *val)
1417 skb_shinfo(skb)->destructor_arg = (void *)((uintptr_t) val | 0x1UL);
1418 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG;
1421 static inline bool skb_zcopy_is_nouarg(struct sk_buff *skb)
1423 return (uintptr_t) skb_shinfo(skb)->destructor_arg & 0x1UL;
1426 static inline void *skb_zcopy_get_nouarg(struct sk_buff *skb)
1428 return (void *)((uintptr_t) skb_shinfo(skb)->destructor_arg & ~0x1UL);
1431 /* Release a reference on a zerocopy structure */
1432 static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
1434 struct ubuf_info *uarg = skb_zcopy(skb);
1437 if (uarg->callback == sock_zerocopy_callback) {
1438 uarg->zerocopy = uarg->zerocopy && zerocopy;
1439 sock_zerocopy_put(uarg);
1440 } else if (!skb_zcopy_is_nouarg(skb)) {
1441 uarg->callback(uarg, zerocopy);
1444 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
1448 /* Abort a zerocopy operation and revert zckey on error in send syscall */
1449 static inline void skb_zcopy_abort(struct sk_buff *skb)
1451 struct ubuf_info *uarg = skb_zcopy(skb);
1454 sock_zerocopy_put_abort(uarg, false);
1455 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
1459 static inline void skb_mark_not_on_list(struct sk_buff *skb)
1464 static inline void skb_list_del_init(struct sk_buff *skb)
1466 __list_del_entry(&skb->list);
1467 skb_mark_not_on_list(skb);
1471 * skb_queue_empty - check if a queue is empty
1474 * Returns true if the queue is empty, false otherwise.
1476 static inline int skb_queue_empty(const struct sk_buff_head *list)
1478 return list->next == (const struct sk_buff *) list;
1482 * skb_queue_is_last - check if skb is the last entry in the queue
1486 * Returns true if @skb is the last buffer on the list.
1488 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1489 const struct sk_buff *skb)
1491 return skb->next == (const struct sk_buff *) list;
1495 * skb_queue_is_first - check if skb is the first entry in the queue
1499 * Returns true if @skb is the first buffer on the list.
1501 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1502 const struct sk_buff *skb)
1504 return skb->prev == (const struct sk_buff *) list;
1508 * skb_queue_next - return the next packet in the queue
1510 * @skb: current buffer
1512 * Return the next packet in @list after @skb. It is only valid to
1513 * call this if skb_queue_is_last() evaluates to false.
1515 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1516 const struct sk_buff *skb)
1518 /* This BUG_ON may seem severe, but if we just return then we
1519 * are going to dereference garbage.
1521 BUG_ON(skb_queue_is_last(list, skb));
1526 * skb_queue_prev - return the prev packet in the queue
1528 * @skb: current buffer
1530 * Return the prev packet in @list before @skb. It is only valid to
1531 * call this if skb_queue_is_first() evaluates to false.
1533 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1534 const struct sk_buff *skb)
1536 /* This BUG_ON may seem severe, but if we just return then we
1537 * are going to dereference garbage.
1539 BUG_ON(skb_queue_is_first(list, skb));
1544 * skb_get - reference buffer
1545 * @skb: buffer to reference
1547 * Makes another reference to a socket buffer and returns a pointer
1550 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1552 refcount_inc(&skb->users);
1557 * If users == 1, we are the only owner and can avoid redundant atomic changes.
1561 * skb_cloned - is the buffer a clone
1562 * @skb: buffer to check
1564 * Returns true if the buffer was generated with skb_clone() and is
1565 * one of multiple shared copies of the buffer. Cloned buffers are
1566 * shared data so must not be written to under normal circumstances.
1568 static inline int skb_cloned(const struct sk_buff *skb)
1570 return skb->cloned &&
1571 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1574 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1576 might_sleep_if(gfpflags_allow_blocking(pri));
1578 if (skb_cloned(skb))
1579 return pskb_expand_head(skb, 0, 0, pri);
1585 * skb_header_cloned - is the header a clone
1586 * @skb: buffer to check
1588 * Returns true if modifying the header part of the buffer requires
1589 * the data to be copied.
1591 static inline int skb_header_cloned(const struct sk_buff *skb)
1598 dataref = atomic_read(&skb_shinfo(skb)->dataref);
1599 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1600 return dataref != 1;
1603 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
1605 might_sleep_if(gfpflags_allow_blocking(pri));
1607 if (skb_header_cloned(skb))
1608 return pskb_expand_head(skb, 0, 0, pri);
1614 * __skb_header_release - release reference to header
1615 * @skb: buffer to operate on
1617 static inline void __skb_header_release(struct sk_buff *skb)
1620 atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1625 * skb_shared - is the buffer shared
1626 * @skb: buffer to check
1628 * Returns true if more than one person has a reference to this
1631 static inline int skb_shared(const struct sk_buff *skb)
1633 return refcount_read(&skb->users) != 1;
1637 * skb_share_check - check if buffer is shared and if so clone it
1638 * @skb: buffer to check
1639 * @pri: priority for memory allocation
1641 * If the buffer is shared the buffer is cloned and the old copy
1642 * drops a reference. A new clone with a single reference is returned.
1643 * If the buffer is not shared the original buffer is returned. When
1644 * being called from interrupt status or with spinlocks held pri must
1647 * NULL is returned on a memory allocation failure.
1649 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1651 might_sleep_if(gfpflags_allow_blocking(pri));
1652 if (skb_shared(skb)) {
1653 struct sk_buff *nskb = skb_clone(skb, pri);
1665 * Copy shared buffers into a new sk_buff. We effectively do COW on
1666 * packets to handle cases where we have a local reader and forward
1667 * and a couple of other messy ones. The normal one is tcpdumping
1668 * a packet thats being forwarded.
1672 * skb_unshare - make a copy of a shared buffer
1673 * @skb: buffer to check
1674 * @pri: priority for memory allocation
1676 * If the socket buffer is a clone then this function creates a new
1677 * copy of the data, drops a reference count on the old copy and returns
1678 * the new copy with the reference count at 1. If the buffer is not a clone
1679 * the original buffer is returned. When called with a spinlock held or
1680 * from interrupt state @pri must be %GFP_ATOMIC
1682 * %NULL is returned on a memory allocation failure.
1684 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1687 might_sleep_if(gfpflags_allow_blocking(pri));
1688 if (skb_cloned(skb)) {
1689 struct sk_buff *nskb = skb_copy(skb, pri);
1691 /* Free our shared copy */
1702 * skb_peek - peek at the head of an &sk_buff_head
1703 * @list_: list to peek at
1705 * Peek an &sk_buff. Unlike most other operations you _MUST_
1706 * be careful with this one. A peek leaves the buffer on the
1707 * list and someone else may run off with it. You must hold
1708 * the appropriate locks or have a private queue to do this.
1710 * Returns %NULL for an empty list or a pointer to the head element.
1711 * The reference count is not incremented and the reference is therefore
1712 * volatile. Use with caution.
1714 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1716 struct sk_buff *skb = list_->next;
1718 if (skb == (struct sk_buff *)list_)
1724 * __skb_peek - peek at the head of a non-empty &sk_buff_head
1725 * @list_: list to peek at
1727 * Like skb_peek(), but the caller knows that the list is not empty.
1729 static inline struct sk_buff *__skb_peek(const struct sk_buff_head *list_)
1735 * skb_peek_next - peek skb following the given one from a queue
1736 * @skb: skb to start from
1737 * @list_: list to peek at
1739 * Returns %NULL when the end of the list is met or a pointer to the
1740 * next element. The reference count is not incremented and the
1741 * reference is therefore volatile. Use with caution.
1743 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1744 const struct sk_buff_head *list_)
1746 struct sk_buff *next = skb->next;
1748 if (next == (struct sk_buff *)list_)
1754 * skb_peek_tail - peek at the tail of an &sk_buff_head
1755 * @list_: list to peek at
1757 * Peek an &sk_buff. Unlike most other operations you _MUST_
1758 * be careful with this one. A peek leaves the buffer on the
1759 * list and someone else may run off with it. You must hold
1760 * the appropriate locks or have a private queue to do this.
1762 * Returns %NULL for an empty list or a pointer to the tail element.
1763 * The reference count is not incremented and the reference is therefore
1764 * volatile. Use with caution.
1766 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1768 struct sk_buff *skb = list_->prev;
1770 if (skb == (struct sk_buff *)list_)
1777 * skb_queue_len - get queue length
1778 * @list_: list to measure
1780 * Return the length of an &sk_buff queue.
1782 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1788 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1789 * @list: queue to initialize
1791 * This initializes only the list and queue length aspects of
1792 * an sk_buff_head object. This allows to initialize the list
1793 * aspects of an sk_buff_head without reinitializing things like
1794 * the spinlock. It can also be used for on-stack sk_buff_head
1795 * objects where the spinlock is known to not be used.
1797 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1799 list->prev = list->next = (struct sk_buff *)list;
1804 * This function creates a split out lock class for each invocation;
1805 * this is needed for now since a whole lot of users of the skb-queue
1806 * infrastructure in drivers have different locking usage (in hardirq)
1807 * than the networking core (in softirq only). In the long run either the
1808 * network layer or drivers should need annotation to consolidate the
1809 * main types of usage into 3 classes.
1811 static inline void skb_queue_head_init(struct sk_buff_head *list)
1813 spin_lock_init(&list->lock);
1814 __skb_queue_head_init(list);
1817 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1818 struct lock_class_key *class)
1820 skb_queue_head_init(list);
1821 lockdep_set_class(&list->lock, class);
1825 * Insert an sk_buff on a list.
1827 * The "__skb_xxxx()" functions are the non-atomic ones that
1828 * can only be called with interrupts disabled.
1830 static inline void __skb_insert(struct sk_buff *newsk,
1831 struct sk_buff *prev, struct sk_buff *next,
1832 struct sk_buff_head *list)
1836 next->prev = prev->next = newsk;
1840 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1841 struct sk_buff *prev,
1842 struct sk_buff *next)
1844 struct sk_buff *first = list->next;
1845 struct sk_buff *last = list->prev;
1855 * skb_queue_splice - join two skb lists, this is designed for stacks
1856 * @list: the new list to add
1857 * @head: the place to add it in the first list
1859 static inline void skb_queue_splice(const struct sk_buff_head *list,
1860 struct sk_buff_head *head)
1862 if (!skb_queue_empty(list)) {
1863 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1864 head->qlen += list->qlen;
1869 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1870 * @list: the new list to add
1871 * @head: the place to add it in the first list
1873 * The list at @list is reinitialised
1875 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1876 struct sk_buff_head *head)
1878 if (!skb_queue_empty(list)) {
1879 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1880 head->qlen += list->qlen;
1881 __skb_queue_head_init(list);
1886 * skb_queue_splice_tail - join two skb lists, each list being a queue
1887 * @list: the new list to add
1888 * @head: the place to add it in the first list
1890 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1891 struct sk_buff_head *head)
1893 if (!skb_queue_empty(list)) {
1894 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1895 head->qlen += list->qlen;
1900 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1901 * @list: the new list to add
1902 * @head: the place to add it in the first list
1904 * Each of the lists is a queue.
1905 * The list at @list is reinitialised
1907 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1908 struct sk_buff_head *head)
1910 if (!skb_queue_empty(list)) {
1911 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1912 head->qlen += list->qlen;
1913 __skb_queue_head_init(list);
1918 * __skb_queue_after - queue a buffer at the list head
1919 * @list: list to use
1920 * @prev: place after this buffer
1921 * @newsk: buffer to queue
1923 * Queue a buffer int the middle of a list. This function takes no locks
1924 * and you must therefore hold required locks before calling it.
1926 * A buffer cannot be placed on two lists at the same time.
1928 static inline void __skb_queue_after(struct sk_buff_head *list,
1929 struct sk_buff *prev,
1930 struct sk_buff *newsk)
1932 __skb_insert(newsk, prev, prev->next, list);
1935 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1936 struct sk_buff_head *list);
1938 static inline void __skb_queue_before(struct sk_buff_head *list,
1939 struct sk_buff *next,
1940 struct sk_buff *newsk)
1942 __skb_insert(newsk, next->prev, next, list);
1946 * __skb_queue_head - queue a buffer at the list head
1947 * @list: list to use
1948 * @newsk: buffer to queue
1950 * Queue a buffer at the start of a list. This function takes no locks
1951 * and you must therefore hold required locks before calling it.
1953 * A buffer cannot be placed on two lists at the same time.
1955 static inline void __skb_queue_head(struct sk_buff_head *list,
1956 struct sk_buff *newsk)
1958 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1960 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1963 * __skb_queue_tail - queue a buffer at the list tail
1964 * @list: list to use
1965 * @newsk: buffer to queue
1967 * Queue a buffer at the end of a list. This function takes no locks
1968 * and you must therefore hold required locks before calling it.
1970 * A buffer cannot be placed on two lists at the same time.
1972 static inline void __skb_queue_tail(struct sk_buff_head *list,
1973 struct sk_buff *newsk)
1975 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1977 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1980 * remove sk_buff from list. _Must_ be called atomically, and with
1983 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1984 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1986 struct sk_buff *next, *prev;
1991 skb->next = skb->prev = NULL;
1997 * __skb_dequeue - remove from the head of the queue
1998 * @list: list to dequeue from
2000 * Remove the head of the list. This function does not take any locks
2001 * so must be used with appropriate locks held only. The head item is
2002 * returned or %NULL if the list is empty.
2004 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
2006 struct sk_buff *skb = skb_peek(list);
2008 __skb_unlink(skb, list);
2011 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
2014 * __skb_dequeue_tail - remove from the tail of the queue
2015 * @list: list to dequeue from
2017 * Remove the tail of the list. This function does not take any locks
2018 * so must be used with appropriate locks held only. The tail item is
2019 * returned or %NULL if the list is empty.
2021 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
2023 struct sk_buff *skb = skb_peek_tail(list);
2025 __skb_unlink(skb, list);
2028 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
2031 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
2033 return skb->data_len;
2036 static inline unsigned int skb_headlen(const struct sk_buff *skb)
2038 return skb->len - skb->data_len;
2041 static inline unsigned int __skb_pagelen(const struct sk_buff *skb)
2043 unsigned int i, len = 0;
2045 for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--)
2046 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
2050 static inline unsigned int skb_pagelen(const struct sk_buff *skb)
2052 return skb_headlen(skb) + __skb_pagelen(skb);
2056 * __skb_fill_page_desc - initialise a paged fragment in an skb
2057 * @skb: buffer containing fragment to be initialised
2058 * @i: paged fragment index to initialise
2059 * @page: the page to use for this fragment
2060 * @off: the offset to the data with @page
2061 * @size: the length of the data
2063 * Initialises the @i'th fragment of @skb to point to &size bytes at
2064 * offset @off within @page.
2066 * Does not take any additional reference on the fragment.
2068 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
2069 struct page *page, int off, int size)
2071 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2074 * Propagate page pfmemalloc to the skb if we can. The problem is
2075 * that not all callers have unique ownership of the page but rely
2076 * on page_is_pfmemalloc doing the right thing(tm).
2078 frag->page.p = page;
2079 frag->page_offset = off;
2080 skb_frag_size_set(frag, size);
2082 page = compound_head(page);
2083 if (page_is_pfmemalloc(page))
2084 skb->pfmemalloc = true;
2088 * skb_fill_page_desc - initialise a paged fragment in an skb
2089 * @skb: buffer containing fragment to be initialised
2090 * @i: paged fragment index to initialise
2091 * @page: the page to use for this fragment
2092 * @off: the offset to the data with @page
2093 * @size: the length of the data
2095 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
2096 * @skb to point to @size bytes at offset @off within @page. In
2097 * addition updates @skb such that @i is the last fragment.
2099 * Does not take any additional reference on the fragment.
2101 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
2102 struct page *page, int off, int size)
2104 __skb_fill_page_desc(skb, i, page, off, size);
2105 skb_shinfo(skb)->nr_frags = i + 1;
2108 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
2109 int size, unsigned int truesize);
2111 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
2112 unsigned int truesize);
2114 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
2116 #ifdef NET_SKBUFF_DATA_USES_OFFSET
2117 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2119 return skb->head + skb->tail;
2122 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2124 skb->tail = skb->data - skb->head;
2127 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2129 skb_reset_tail_pointer(skb);
2130 skb->tail += offset;
2133 #else /* NET_SKBUFF_DATA_USES_OFFSET */
2134 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2139 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2141 skb->tail = skb->data;
2144 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2146 skb->tail = skb->data + offset;
2149 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
2152 * Add data to an sk_buff
2154 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
2155 void *skb_put(struct sk_buff *skb, unsigned int len);
2156 static inline void *__skb_put(struct sk_buff *skb, unsigned int len)
2158 void *tmp = skb_tail_pointer(skb);
2159 SKB_LINEAR_ASSERT(skb);
2165 static inline void *__skb_put_zero(struct sk_buff *skb, unsigned int len)
2167 void *tmp = __skb_put(skb, len);
2169 memset(tmp, 0, len);
2173 static inline void *__skb_put_data(struct sk_buff *skb, const void *data,
2176 void *tmp = __skb_put(skb, len);
2178 memcpy(tmp, data, len);
2182 static inline void __skb_put_u8(struct sk_buff *skb, u8 val)
2184 *(u8 *)__skb_put(skb, 1) = val;
2187 static inline void *skb_put_zero(struct sk_buff *skb, unsigned int len)
2189 void *tmp = skb_put(skb, len);
2191 memset(tmp, 0, len);
2196 static inline void *skb_put_data(struct sk_buff *skb, const void *data,
2199 void *tmp = skb_put(skb, len);
2201 memcpy(tmp, data, len);
2206 static inline void skb_put_u8(struct sk_buff *skb, u8 val)
2208 *(u8 *)skb_put(skb, 1) = val;
2211 void *skb_push(struct sk_buff *skb, unsigned int len);
2212 static inline void *__skb_push(struct sk_buff *skb, unsigned int len)
2219 void *skb_pull(struct sk_buff *skb, unsigned int len);
2220 static inline void *__skb_pull(struct sk_buff *skb, unsigned int len)
2223 BUG_ON(skb->len < skb->data_len);
2224 return skb->data += len;
2227 static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len)
2229 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
2232 void *__pskb_pull_tail(struct sk_buff *skb, int delta);
2234 static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len)
2236 if (len > skb_headlen(skb) &&
2237 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
2240 return skb->data += len;
2243 static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
2245 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
2248 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
2250 if (likely(len <= skb_headlen(skb)))
2252 if (unlikely(len > skb->len))
2254 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
2257 void skb_condense(struct sk_buff *skb);
2260 * skb_headroom - bytes at buffer head
2261 * @skb: buffer to check
2263 * Return the number of bytes of free space at the head of an &sk_buff.
2265 static inline unsigned int skb_headroom(const struct sk_buff *skb)
2267 return skb->data - skb->head;
2271 * skb_tailroom - bytes at buffer end
2272 * @skb: buffer to check
2274 * Return the number of bytes of free space at the tail of an sk_buff
2276 static inline int skb_tailroom(const struct sk_buff *skb)
2278 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
2282 * skb_availroom - bytes at buffer end
2283 * @skb: buffer to check
2285 * Return the number of bytes of free space at the tail of an sk_buff
2286 * allocated by sk_stream_alloc()
2288 static inline int skb_availroom(const struct sk_buff *skb)
2290 if (skb_is_nonlinear(skb))
2293 return skb->end - skb->tail - skb->reserved_tailroom;
2297 * skb_reserve - adjust headroom
2298 * @skb: buffer to alter
2299 * @len: bytes to move
2301 * Increase the headroom of an empty &sk_buff by reducing the tail
2302 * room. This is only allowed for an empty buffer.
2304 static inline void skb_reserve(struct sk_buff *skb, int len)
2311 * skb_tailroom_reserve - adjust reserved_tailroom
2312 * @skb: buffer to alter
2313 * @mtu: maximum amount of headlen permitted
2314 * @needed_tailroom: minimum amount of reserved_tailroom
2316 * Set reserved_tailroom so that headlen can be as large as possible but
2317 * not larger than mtu and tailroom cannot be smaller than
2319 * The required headroom should already have been reserved before using
2322 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2323 unsigned int needed_tailroom)
2325 SKB_LINEAR_ASSERT(skb);
2326 if (mtu < skb_tailroom(skb) - needed_tailroom)
2327 /* use at most mtu */
2328 skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2330 /* use up to all available space */
2331 skb->reserved_tailroom = needed_tailroom;
2334 #define ENCAP_TYPE_ETHER 0
2335 #define ENCAP_TYPE_IPPROTO 1
2337 static inline void skb_set_inner_protocol(struct sk_buff *skb,
2340 skb->inner_protocol = protocol;
2341 skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2344 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2347 skb->inner_ipproto = ipproto;
2348 skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2351 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2353 skb->inner_mac_header = skb->mac_header;
2354 skb->inner_network_header = skb->network_header;
2355 skb->inner_transport_header = skb->transport_header;
2358 static inline void skb_reset_mac_len(struct sk_buff *skb)
2360 skb->mac_len = skb->network_header - skb->mac_header;
2363 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2366 return skb->head + skb->inner_transport_header;
2369 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2371 return skb_inner_transport_header(skb) - skb->data;
2374 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2376 skb->inner_transport_header = skb->data - skb->head;
2379 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2382 skb_reset_inner_transport_header(skb);
2383 skb->inner_transport_header += offset;
2386 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2388 return skb->head + skb->inner_network_header;
2391 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2393 skb->inner_network_header = skb->data - skb->head;
2396 static inline void skb_set_inner_network_header(struct sk_buff *skb,
2399 skb_reset_inner_network_header(skb);
2400 skb->inner_network_header += offset;
2403 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2405 return skb->head + skb->inner_mac_header;
2408 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2410 skb->inner_mac_header = skb->data - skb->head;
2413 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2416 skb_reset_inner_mac_header(skb);
2417 skb->inner_mac_header += offset;
2419 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2421 return skb->transport_header != (typeof(skb->transport_header))~0U;
2424 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2426 return skb->head + skb->transport_header;
2429 static inline void skb_reset_transport_header(struct sk_buff *skb)
2431 skb->transport_header = skb->data - skb->head;
2434 static inline void skb_set_transport_header(struct sk_buff *skb,
2437 skb_reset_transport_header(skb);
2438 skb->transport_header += offset;
2441 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2443 return skb->head + skb->network_header;
2446 static inline void skb_reset_network_header(struct sk_buff *skb)
2448 skb->network_header = skb->data - skb->head;
2451 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2453 skb_reset_network_header(skb);
2454 skb->network_header += offset;
2457 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2459 return skb->head + skb->mac_header;
2462 static inline int skb_mac_offset(const struct sk_buff *skb)
2464 return skb_mac_header(skb) - skb->data;
2467 static inline u32 skb_mac_header_len(const struct sk_buff *skb)
2469 return skb->network_header - skb->mac_header;
2472 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2474 return skb->mac_header != (typeof(skb->mac_header))~0U;
2477 static inline void skb_reset_mac_header(struct sk_buff *skb)
2479 skb->mac_header = skb->data - skb->head;
2482 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2484 skb_reset_mac_header(skb);
2485 skb->mac_header += offset;
2488 static inline void skb_pop_mac_header(struct sk_buff *skb)
2490 skb->mac_header = skb->network_header;
2493 static inline void skb_probe_transport_header(struct sk_buff *skb)
2495 struct flow_keys_basic keys;
2497 if (skb_transport_header_was_set(skb))
2500 if (skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
2502 skb_set_transport_header(skb, keys.control.thoff);
2505 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2507 if (skb_mac_header_was_set(skb)) {
2508 const unsigned char *old_mac = skb_mac_header(skb);
2510 skb_set_mac_header(skb, -skb->mac_len);
2511 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2515 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2517 return skb->csum_start - skb_headroom(skb);
2520 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
2522 return skb->head + skb->csum_start;
2525 static inline int skb_transport_offset(const struct sk_buff *skb)
2527 return skb_transport_header(skb) - skb->data;
2530 static inline u32 skb_network_header_len(const struct sk_buff *skb)
2532 return skb->transport_header - skb->network_header;
2535 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2537 return skb->inner_transport_header - skb->inner_network_header;
2540 static inline int skb_network_offset(const struct sk_buff *skb)
2542 return skb_network_header(skb) - skb->data;
2545 static inline int skb_inner_network_offset(const struct sk_buff *skb)
2547 return skb_inner_network_header(skb) - skb->data;
2550 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2552 return pskb_may_pull(skb, skb_network_offset(skb) + len);
2556 * CPUs often take a performance hit when accessing unaligned memory
2557 * locations. The actual performance hit varies, it can be small if the
2558 * hardware handles it or large if we have to take an exception and fix it
2561 * Since an ethernet header is 14 bytes network drivers often end up with
2562 * the IP header at an unaligned offset. The IP header can be aligned by
2563 * shifting the start of the packet by 2 bytes. Drivers should do this
2566 * skb_reserve(skb, NET_IP_ALIGN);
2568 * The downside to this alignment of the IP header is that the DMA is now
2569 * unaligned. On some architectures the cost of an unaligned DMA is high
2570 * and this cost outweighs the gains made by aligning the IP header.
2572 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2575 #ifndef NET_IP_ALIGN
2576 #define NET_IP_ALIGN 2
2580 * The networking layer reserves some headroom in skb data (via
2581 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2582 * the header has to grow. In the default case, if the header has to grow
2583 * 32 bytes or less we avoid the reallocation.
2585 * Unfortunately this headroom changes the DMA alignment of the resulting
2586 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2587 * on some architectures. An architecture can override this value,
2588 * perhaps setting it to a cacheline in size (since that will maintain
2589 * cacheline alignment of the DMA). It must be a power of 2.
2591 * Various parts of the networking layer expect at least 32 bytes of
2592 * headroom, you should not reduce this.
2594 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2595 * to reduce average number of cache lines per packet.
2596 * get_rps_cpus() for example only access one 64 bytes aligned block :
2597 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2600 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
2603 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2605 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
2607 if (WARN_ON(skb_is_nonlinear(skb)))
2610 skb_set_tail_pointer(skb, len);
2613 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2615 __skb_set_length(skb, len);
2618 void skb_trim(struct sk_buff *skb, unsigned int len);
2620 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2623 return ___pskb_trim(skb, len);
2624 __skb_trim(skb, len);
2628 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2630 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2634 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2635 * @skb: buffer to alter
2638 * This is identical to pskb_trim except that the caller knows that
2639 * the skb is not cloned so we should never get an error due to out-
2642 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2644 int err = pskb_trim(skb, len);
2648 static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
2650 unsigned int diff = len - skb->len;
2652 if (skb_tailroom(skb) < diff) {
2653 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
2658 __skb_set_length(skb, len);
2663 * skb_orphan - orphan a buffer
2664 * @skb: buffer to orphan
2666 * If a buffer currently has an owner then we call the owner's
2667 * destructor function and make the @skb unowned. The buffer continues
2668 * to exist but is no longer charged to its former owner.
2670 static inline void skb_orphan(struct sk_buff *skb)
2672 if (skb->destructor) {
2673 skb->destructor(skb);
2674 skb->destructor = NULL;
2682 * skb_orphan_frags - orphan the frags contained in a buffer
2683 * @skb: buffer to orphan frags from
2684 * @gfp_mask: allocation mask for replacement pages
2686 * For each frag in the SKB which needs a destructor (i.e. has an
2687 * owner) create a copy of that frag and release the original
2688 * page by calling the destructor.
2690 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2692 if (likely(!skb_zcopy(skb)))
2694 if (skb_uarg(skb)->callback == sock_zerocopy_callback)
2696 return skb_copy_ubufs(skb, gfp_mask);
2699 /* Frags must be orphaned, even if refcounted, if skb might loop to rx path */
2700 static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask)
2702 if (likely(!skb_zcopy(skb)))
2704 return skb_copy_ubufs(skb, gfp_mask);
2708 * __skb_queue_purge - empty a list
2709 * @list: list to empty
2711 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2712 * the list and one reference dropped. This function does not take the
2713 * list lock and the caller must hold the relevant locks to use it.
2715 static inline void __skb_queue_purge(struct sk_buff_head *list)
2717 struct sk_buff *skb;
2718 while ((skb = __skb_dequeue(list)) != NULL)
2721 void skb_queue_purge(struct sk_buff_head *list);
2723 unsigned int skb_rbtree_purge(struct rb_root *root);
2725 void *netdev_alloc_frag(unsigned int fragsz);
2727 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2731 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
2732 * @dev: network device to receive on
2733 * @length: length to allocate
2735 * Allocate a new &sk_buff and assign it a usage count of one. The
2736 * buffer has unspecified headroom built in. Users should allocate
2737 * the headroom they think they need without accounting for the
2738 * built in space. The built in space is used for optimisations.
2740 * %NULL is returned if there is no free memory. Although this function
2741 * allocates memory it can be called from an interrupt.
2743 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2744 unsigned int length)
2746 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2749 /* legacy helper around __netdev_alloc_skb() */
2750 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2753 return __netdev_alloc_skb(NULL, length, gfp_mask);
2756 /* legacy helper around netdev_alloc_skb() */
2757 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2759 return netdev_alloc_skb(NULL, length);
2763 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2764 unsigned int length, gfp_t gfp)
2766 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2768 if (NET_IP_ALIGN && skb)
2769 skb_reserve(skb, NET_IP_ALIGN);
2773 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2774 unsigned int length)
2776 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2779 static inline void skb_free_frag(void *addr)
2781 page_frag_free(addr);
2784 void *napi_alloc_frag(unsigned int fragsz);
2785 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2786 unsigned int length, gfp_t gfp_mask);
2787 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2788 unsigned int length)
2790 return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2792 void napi_consume_skb(struct sk_buff *skb, int budget);
2794 void __kfree_skb_flush(void);
2795 void __kfree_skb_defer(struct sk_buff *skb);
2798 * __dev_alloc_pages - allocate page for network Rx
2799 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2800 * @order: size of the allocation
2802 * Allocate a new page.
2804 * %NULL is returned if there is no free memory.
2806 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2809 /* This piece of code contains several assumptions.
2810 * 1. This is for device Rx, therefor a cold page is preferred.
2811 * 2. The expectation is the user wants a compound page.
2812 * 3. If requesting a order 0 page it will not be compound
2813 * due to the check to see if order has a value in prep_new_page
2814 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2815 * code in gfp_to_alloc_flags that should be enforcing this.
2817 gfp_mask |= __GFP_COMP | __GFP_MEMALLOC;
2819 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2822 static inline struct page *dev_alloc_pages(unsigned int order)
2824 return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
2828 * __dev_alloc_page - allocate a page for network Rx
2829 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2831 * Allocate a new page.
2833 * %NULL is returned if there is no free memory.
2835 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2837 return __dev_alloc_pages(gfp_mask, 0);
2840 static inline struct page *dev_alloc_page(void)
2842 return dev_alloc_pages(0);
2846 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2847 * @page: The page that was allocated from skb_alloc_page
2848 * @skb: The skb that may need pfmemalloc set
2850 static inline void skb_propagate_pfmemalloc(struct page *page,
2851 struct sk_buff *skb)
2853 if (page_is_pfmemalloc(page))
2854 skb->pfmemalloc = true;
2858 * skb_frag_page - retrieve the page referred to by a paged fragment
2859 * @frag: the paged fragment
2861 * Returns the &struct page associated with @frag.
2863 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2865 return frag->page.p;
2869 * __skb_frag_ref - take an addition reference on a paged fragment.
2870 * @frag: the paged fragment
2872 * Takes an additional reference on the paged fragment @frag.
2874 static inline void __skb_frag_ref(skb_frag_t *frag)
2876 get_page(skb_frag_page(frag));
2880 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2882 * @f: the fragment offset.
2884 * Takes an additional reference on the @f'th paged fragment of @skb.
2886 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2888 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2892 * __skb_frag_unref - release a reference on a paged fragment.
2893 * @frag: the paged fragment
2895 * Releases a reference on the paged fragment @frag.
2897 static inline void __skb_frag_unref(skb_frag_t *frag)
2899 put_page(skb_frag_page(frag));
2903 * skb_frag_unref - release a reference on a paged fragment of an skb.
2905 * @f: the fragment offset
2907 * Releases a reference on the @f'th paged fragment of @skb.
2909 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2911 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2915 * skb_frag_address - gets the address of the data contained in a paged fragment
2916 * @frag: the paged fragment buffer
2918 * Returns the address of the data within @frag. The page must already
2921 static inline void *skb_frag_address(const skb_frag_t *frag)
2923 return page_address(skb_frag_page(frag)) + frag->page_offset;
2927 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2928 * @frag: the paged fragment buffer
2930 * Returns the address of the data within @frag. Checks that the page
2931 * is mapped and returns %NULL otherwise.
2933 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2935 void *ptr = page_address(skb_frag_page(frag));
2939 return ptr + frag->page_offset;
2943 * __skb_frag_set_page - sets the page contained in a paged fragment
2944 * @frag: the paged fragment
2945 * @page: the page to set
2947 * Sets the fragment @frag to contain @page.
2949 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2951 frag->page.p = page;
2955 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2957 * @f: the fragment offset
2958 * @page: the page to set
2960 * Sets the @f'th fragment of @skb to contain @page.
2962 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2965 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2968 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2971 * skb_frag_dma_map - maps a paged fragment via the DMA API
2972 * @dev: the device to map the fragment to
2973 * @frag: the paged fragment to map
2974 * @offset: the offset within the fragment (starting at the
2975 * fragment's own offset)
2976 * @size: the number of bytes to map
2977 * @dir: the direction of the mapping (``PCI_DMA_*``)
2979 * Maps the page associated with @frag to @device.
2981 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2982 const skb_frag_t *frag,
2983 size_t offset, size_t size,
2984 enum dma_data_direction dir)
2986 return dma_map_page(dev, skb_frag_page(frag),
2987 frag->page_offset + offset, size, dir);
2990 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2993 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2997 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
3000 return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
3005 * skb_clone_writable - is the header of a clone writable
3006 * @skb: buffer to check
3007 * @len: length up to which to write
3009 * Returns true if modifying the header part of the cloned buffer
3010 * does not requires the data to be copied.
3012 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
3014 return !skb_header_cloned(skb) &&
3015 skb_headroom(skb) + len <= skb->hdr_len;
3018 static inline int skb_try_make_writable(struct sk_buff *skb,
3019 unsigned int write_len)
3021 return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
3022 pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
3025 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
3030 if (headroom > skb_headroom(skb))
3031 delta = headroom - skb_headroom(skb);
3033 if (delta || cloned)
3034 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
3040 * skb_cow - copy header of skb when it is required
3041 * @skb: buffer to cow
3042 * @headroom: needed headroom
3044 * If the skb passed lacks sufficient headroom or its data part
3045 * is shared, data is reallocated. If reallocation fails, an error
3046 * is returned and original skb is not changed.
3048 * The result is skb with writable area skb->head...skb->tail
3049 * and at least @headroom of space at head.
3051 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
3053 return __skb_cow(skb, headroom, skb_cloned(skb));
3057 * skb_cow_head - skb_cow but only making the head writable
3058 * @skb: buffer to cow
3059 * @headroom: needed headroom
3061 * This function is identical to skb_cow except that we replace the
3062 * skb_cloned check by skb_header_cloned. It should be used when
3063 * you only need to push on some header and do not need to modify
3066 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
3068 return __skb_cow(skb, headroom, skb_header_cloned(skb));
3072 * skb_padto - pad an skbuff up to a minimal size
3073 * @skb: buffer to pad
3074 * @len: minimal length
3076 * Pads up a buffer to ensure the trailing bytes exist and are
3077 * blanked. If the buffer already contains sufficient data it
3078 * is untouched. Otherwise it is extended. Returns zero on
3079 * success. The skb is freed on error.
3081 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
3083 unsigned int size = skb->len;
3084 if (likely(size >= len))
3086 return skb_pad(skb, len - size);
3090 * __skb_put_padto - increase size and pad an skbuff up to a minimal size
3091 * @skb: buffer to pad
3092 * @len: minimal length
3093 * @free_on_error: free buffer on error
3095 * Pads up a buffer to ensure the trailing bytes exist and are
3096 * blanked. If the buffer already contains sufficient data it
3097 * is untouched. Otherwise it is extended. Returns zero on
3098 * success. The skb is freed on error if @free_on_error is true.
3100 static inline int __skb_put_padto(struct sk_buff *skb, unsigned int len,
3103 unsigned int size = skb->len;
3105 if (unlikely(size < len)) {
3107 if (__skb_pad(skb, len, free_on_error))
3109 __skb_put(skb, len);
3115 * skb_put_padto - increase size and pad an skbuff up to a minimal size
3116 * @skb: buffer to pad
3117 * @len: minimal length
3119 * Pads up a buffer to ensure the trailing bytes exist and are
3120 * blanked. If the buffer already contains sufficient data it
3121 * is untouched. Otherwise it is extended. Returns zero on
3122 * success. The skb is freed on error.
3124 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
3126 return __skb_put_padto(skb, len, true);
3129 static inline int skb_add_data(struct sk_buff *skb,
3130 struct iov_iter *from, int copy)
3132 const int off = skb->len;
3134 if (skb->ip_summed == CHECKSUM_NONE) {
3136 if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy,
3138 skb->csum = csum_block_add(skb->csum, csum, off);
3141 } else if (copy_from_iter_full(skb_put(skb, copy), copy, from))
3144 __skb_trim(skb, off);
3148 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
3149 const struct page *page, int off)
3154 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
3156 return page == skb_frag_page(frag) &&
3157 off == frag->page_offset + skb_frag_size(frag);
3162 static inline int __skb_linearize(struct sk_buff *skb)
3164 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
3168 * skb_linearize - convert paged skb to linear one
3169 * @skb: buffer to linarize
3171 * If there is no free memory -ENOMEM is returned, otherwise zero
3172 * is returned and the old skb data released.
3174 static inline int skb_linearize(struct sk_buff *skb)
3176 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
3180 * skb_has_shared_frag - can any frag be overwritten
3181 * @skb: buffer to test
3183 * Return true if the skb has at least one frag that might be modified
3184 * by an external entity (as in vmsplice()/sendfile())
3186 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
3188 return skb_is_nonlinear(skb) &&
3189 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
3193 * skb_linearize_cow - make sure skb is linear and writable
3194 * @skb: buffer to process
3196 * If there is no free memory -ENOMEM is returned, otherwise zero
3197 * is returned and the old skb data released.
3199 static inline int skb_linearize_cow(struct sk_buff *skb)
3201 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
3202 __skb_linearize(skb) : 0;
3205 static __always_inline void
3206 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
3209 if (skb->ip_summed == CHECKSUM_COMPLETE)
3210 skb->csum = csum_block_sub(skb->csum,
3211 csum_partial(start, len, 0), off);
3212 else if (skb->ip_summed == CHECKSUM_PARTIAL &&
3213 skb_checksum_start_offset(skb) < 0)
3214 skb->ip_summed = CHECKSUM_NONE;
3218 * skb_postpull_rcsum - update checksum for received skb after pull
3219 * @skb: buffer to update
3220 * @start: start of data before pull
3221 * @len: length of data pulled
3223 * After doing a pull on a received packet, you need to call this to
3224 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
3225 * CHECKSUM_NONE so that it can be recomputed from scratch.
3227 static inline void skb_postpull_rcsum(struct sk_buff *skb,
3228 const void *start, unsigned int len)
3230 __skb_postpull_rcsum(skb, start, len, 0);
3233 static __always_inline void
3234 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
3237 if (skb->ip_summed == CHECKSUM_COMPLETE)
3238 skb->csum = csum_block_add(skb->csum,
3239 csum_partial(start, len, 0), off);
3243 * skb_postpush_rcsum - update checksum for received skb after push
3244 * @skb: buffer to update
3245 * @start: start of data after push
3246 * @len: length of data pushed
3248 * After doing a push on a received packet, you need to call this to
3249 * update the CHECKSUM_COMPLETE checksum.
3251 static inline void skb_postpush_rcsum(struct sk_buff *skb,
3252 const void *start, unsigned int len)
3254 __skb_postpush_rcsum(skb, start, len, 0);
3257 void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
3260 * skb_push_rcsum - push skb and update receive checksum
3261 * @skb: buffer to update
3262 * @len: length of data pulled
3264 * This function performs an skb_push on the packet and updates
3265 * the CHECKSUM_COMPLETE checksum. It should be used on
3266 * receive path processing instead of skb_push unless you know
3267 * that the checksum difference is zero (e.g., a valid IP header)
3268 * or you are setting ip_summed to CHECKSUM_NONE.
3270 static inline void *skb_push_rcsum(struct sk_buff *skb, unsigned int len)
3273 skb_postpush_rcsum(skb, skb->data, len);
3277 int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len);
3279 * pskb_trim_rcsum - trim received skb and update checksum
3280 * @skb: buffer to trim
3283 * This is exactly the same as pskb_trim except that it ensures the
3284 * checksum of received packets are still valid after the operation.
3285 * It can change skb pointers.
3288 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
3290 if (likely(len >= skb->len))
3292 return pskb_trim_rcsum_slow(skb, len);
3295 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
3297 if (skb->ip_summed == CHECKSUM_COMPLETE)
3298 skb->ip_summed = CHECKSUM_NONE;
3299 __skb_trim(skb, len);
3303 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
3305 if (skb->ip_summed == CHECKSUM_COMPLETE)
3306 skb->ip_summed = CHECKSUM_NONE;
3307 return __skb_grow(skb, len);
3310 #define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode)
3311 #define skb_rb_first(root) rb_to_skb(rb_first(root))
3312 #define skb_rb_last(root) rb_to_skb(rb_last(root))
3313 #define skb_rb_next(skb) rb_to_skb(rb_next(&(skb)->rbnode))
3314 #define skb_rb_prev(skb) rb_to_skb(rb_prev(&(skb)->rbnode))
3316 #define skb_queue_walk(queue, skb) \
3317 for (skb = (queue)->next; \
3318 skb != (struct sk_buff *)(queue); \
3321 #define skb_queue_walk_safe(queue, skb, tmp) \
3322 for (skb = (queue)->next, tmp = skb->next; \
3323 skb != (struct sk_buff *)(queue); \
3324 skb = tmp, tmp = skb->next)
3326 #define skb_queue_walk_from(queue, skb) \
3327 for (; skb != (struct sk_buff *)(queue); \
3330 #define skb_rbtree_walk(skb, root) \
3331 for (skb = skb_rb_first(root); skb != NULL; \
3332 skb = skb_rb_next(skb))
3334 #define skb_rbtree_walk_from(skb) \
3335 for (; skb != NULL; \
3336 skb = skb_rb_next(skb))
3338 #define skb_rbtree_walk_from_safe(skb, tmp) \
3339 for (; tmp = skb ? skb_rb_next(skb) : NULL, (skb != NULL); \
3342 #define skb_queue_walk_from_safe(queue, skb, tmp) \
3343 for (tmp = skb->next; \
3344 skb != (struct sk_buff *)(queue); \
3345 skb = tmp, tmp = skb->next)
3347 #define skb_queue_reverse_walk(queue, skb) \
3348 for (skb = (queue)->prev; \
3349 skb != (struct sk_buff *)(queue); \
3352 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
3353 for (skb = (queue)->prev, tmp = skb->prev; \
3354 skb != (struct sk_buff *)(queue); \
3355 skb = tmp, tmp = skb->prev)
3357 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
3358 for (tmp = skb->prev; \
3359 skb != (struct sk_buff *)(queue); \
3360 skb = tmp, tmp = skb->prev)
3362 static inline bool skb_has_frag_list(const struct sk_buff *skb)
3364 return skb_shinfo(skb)->frag_list != NULL;
3367 static inline void skb_frag_list_init(struct sk_buff *skb)
3369 skb_shinfo(skb)->frag_list = NULL;
3372 #define skb_walk_frags(skb, iter) \
3373 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3376 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
3377 const struct sk_buff *skb);
3378 struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
3379 struct sk_buff_head *queue,
3381 void (*destructor)(struct sock *sk,
3382 struct sk_buff *skb),
3384 struct sk_buff **last);
3385 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
3386 void (*destructor)(struct sock *sk,
3387 struct sk_buff *skb),
3389 struct sk_buff **last);
3390 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
3391 void (*destructor)(struct sock *sk,
3392 struct sk_buff *skb),
3393 int *off, int *err);
3394 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
3396 __poll_t datagram_poll(struct file *file, struct socket *sock,
3397 struct poll_table_struct *wait);
3398 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
3399 struct iov_iter *to, int size);
3400 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
3401 struct msghdr *msg, int size)
3403 return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
3405 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
3406 struct msghdr *msg);
3407 int skb_copy_and_hash_datagram_iter(const struct sk_buff *skb, int offset,
3408 struct iov_iter *to, int len,
3409 struct ahash_request *hash);
3410 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
3411 struct iov_iter *from, int len);
3412 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
3413 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
3414 void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
3415 static inline void skb_free_datagram_locked(struct sock *sk,
3416 struct sk_buff *skb)
3418 __skb_free_datagram_locked(sk, skb, 0);
3420 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
3421 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
3422 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
3423 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
3424 int len, __wsum csum);
3425 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3426 struct pipe_inode_info *pipe, unsigned int len,
3427 unsigned int flags);
3428 int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
3430 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
3431 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
3432 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
3434 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
3435 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
3436 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
3437 bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu);
3438 bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len);
3439 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
3440 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
3441 int skb_ensure_writable(struct sk_buff *skb, int write_len);
3442 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
3443 int skb_vlan_pop(struct sk_buff *skb);
3444 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
3445 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
3448 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
3450 return copy_from_iter_full(data, len, &msg->msg_iter) ? 0 : -EFAULT;
3453 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
3455 return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3458 struct skb_checksum_ops {
3459 __wsum (*update)(const void *mem, int len, __wsum wsum);
3460 __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
3463 extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly;
3465 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3466 __wsum csum, const struct skb_checksum_ops *ops);
3467 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
3470 static inline void * __must_check
3471 __skb_header_pointer(const struct sk_buff *skb, int offset,
3472 int len, void *data, int hlen, void *buffer)
3474 if (hlen - offset >= len)
3475 return data + offset;
3478 skb_copy_bits(skb, offset, buffer, len) < 0)
3484 static inline void * __must_check
3485 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
3487 return __skb_header_pointer(skb, offset, len, skb->data,
3488 skb_headlen(skb), buffer);
3492 * skb_needs_linearize - check if we need to linearize a given skb
3493 * depending on the given device features.
3494 * @skb: socket buffer to check
3495 * @features: net device features
3497 * Returns true if either:
3498 * 1. skb has frag_list and the device doesn't support FRAGLIST, or
3499 * 2. skb is fragmented and the device does not support SG.
3501 static inline bool skb_needs_linearize(struct sk_buff *skb,
3502 netdev_features_t features)
3504 return skb_is_nonlinear(skb) &&
3505 ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3506 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3509 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3511 const unsigned int len)
3513 memcpy(to, skb->data, len);
3516 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3517 const int offset, void *to,
3518 const unsigned int len)
3520 memcpy(to, skb->data + offset, len);
3523 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3525 const unsigned int len)
3527 memcpy(skb->data, from, len);
3530 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3533 const unsigned int len)
3535 memcpy(skb->data + offset, from, len);
3538 void skb_init(void);
3540 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3546 * skb_get_timestamp - get timestamp from a skb
3547 * @skb: skb to get stamp from
3548 * @stamp: pointer to struct __kernel_old_timeval to store stamp in
3550 * Timestamps are stored in the skb as offsets to a base timestamp.
3551 * This function converts the offset back to a struct timeval and stores
3554 static inline void skb_get_timestamp(const struct sk_buff *skb,
3555 struct __kernel_old_timeval *stamp)
3557 *stamp = ns_to_kernel_old_timeval(skb->tstamp);
3560 static inline void skb_get_new_timestamp(const struct sk_buff *skb,
3561 struct __kernel_sock_timeval *stamp)
3563 struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
3565 stamp->tv_sec = ts.tv_sec;
3566 stamp->tv_usec = ts.tv_nsec / 1000;
3569 static inline void skb_get_timestampns(const struct sk_buff *skb,
3570 struct timespec *stamp)
3572 *stamp = ktime_to_timespec(skb->tstamp);
3575 static inline void skb_get_new_timestampns(const struct sk_buff *skb,
3576 struct __kernel_timespec *stamp)
3578 struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
3580 stamp->tv_sec = ts.tv_sec;
3581 stamp->tv_nsec = ts.tv_nsec;
3584 static inline void __net_timestamp(struct sk_buff *skb)
3586 skb->tstamp = ktime_get_real();
3589 static inline ktime_t net_timedelta(ktime_t t)
3591 return ktime_sub(ktime_get_real(), t);
3594 static inline ktime_t net_invalid_timestamp(void)
3599 static inline u8 skb_metadata_len(const struct sk_buff *skb)
3601 return skb_shinfo(skb)->meta_len;
3604 static inline void *skb_metadata_end(const struct sk_buff *skb)
3606 return skb_mac_header(skb);
3609 static inline bool __skb_metadata_differs(const struct sk_buff *skb_a,
3610 const struct sk_buff *skb_b,
3613 const void *a = skb_metadata_end(skb_a);
3614 const void *b = skb_metadata_end(skb_b);
3615 /* Using more efficient varaiant than plain call to memcmp(). */
3616 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
3620 #define __it(x, op) (x -= sizeof(u##op))
3621 #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op))
3622 case 32: diffs |= __it_diff(a, b, 64);
3624 case 24: diffs |= __it_diff(a, b, 64);
3626 case 16: diffs |= __it_diff(a, b, 64);
3628 case 8: diffs |= __it_diff(a, b, 64);
3630 case 28: diffs |= __it_diff(a, b, 64);
3632 case 20: diffs |= __it_diff(a, b, 64);
3634 case 12: diffs |= __it_diff(a, b, 64);
3636 case 4: diffs |= __it_diff(a, b, 32);
3641 return memcmp(a - meta_len, b - meta_len, meta_len);
3645 static inline bool skb_metadata_differs(const struct sk_buff *skb_a,
3646 const struct sk_buff *skb_b)
3648 u8 len_a = skb_metadata_len(skb_a);
3649 u8 len_b = skb_metadata_len(skb_b);
3651 if (!(len_a | len_b))
3654 return len_a != len_b ?
3655 true : __skb_metadata_differs(skb_a, skb_b, len_a);
3658 static inline void skb_metadata_set(struct sk_buff *skb, u8 meta_len)
3660 skb_shinfo(skb)->meta_len = meta_len;
3663 static inline void skb_metadata_clear(struct sk_buff *skb)
3665 skb_metadata_set(skb, 0);
3668 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3670 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3672 void skb_clone_tx_timestamp(struct sk_buff *skb);
3673 bool skb_defer_rx_timestamp(struct sk_buff *skb);
3675 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3677 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3681 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3686 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3689 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3691 * PHY drivers may accept clones of transmitted packets for
3692 * timestamping via their phy_driver.txtstamp method. These drivers
3693 * must call this function to return the skb back to the stack with a
3696 * @skb: clone of the the original outgoing packet
3697 * @hwtstamps: hardware time stamps
3700 void skb_complete_tx_timestamp(struct sk_buff *skb,
3701 struct skb_shared_hwtstamps *hwtstamps);
3703 void __skb_tstamp_tx(struct sk_buff *orig_skb,
3704 struct skb_shared_hwtstamps *hwtstamps,
3705 struct sock *sk, int tstype);
3708 * skb_tstamp_tx - queue clone of skb with send time stamps
3709 * @orig_skb: the original outgoing packet
3710 * @hwtstamps: hardware time stamps, may be NULL if not available
3712 * If the skb has a socket associated, then this function clones the
3713 * skb (thus sharing the actual data and optional structures), stores
3714 * the optional hardware time stamping information (if non NULL) or
3715 * generates a software time stamp (otherwise), then queues the clone
3716 * to the error queue of the socket. Errors are silently ignored.
3718 void skb_tstamp_tx(struct sk_buff *orig_skb,
3719 struct skb_shared_hwtstamps *hwtstamps);
3722 * skb_tx_timestamp() - Driver hook for transmit timestamping
3724 * Ethernet MAC Drivers should call this function in their hard_xmit()
3725 * function immediately before giving the sk_buff to the MAC hardware.
3727 * Specifically, one should make absolutely sure that this function is
3728 * called before TX completion of this packet can trigger. Otherwise
3729 * the packet could potentially already be freed.
3731 * @skb: A socket buffer.
3733 static inline void skb_tx_timestamp(struct sk_buff *skb)
3735 skb_clone_tx_timestamp(skb);
3736 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
3737 skb_tstamp_tx(skb, NULL);
3741 * skb_complete_wifi_ack - deliver skb with wifi status
3743 * @skb: the original outgoing packet
3744 * @acked: ack status
3747 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3749 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3750 __sum16 __skb_checksum_complete(struct sk_buff *skb);
3752 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3754 return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3756 (skb->ip_summed == CHECKSUM_PARTIAL &&
3757 skb_checksum_start_offset(skb) >= 0));
3761 * skb_checksum_complete - Calculate checksum of an entire packet
3762 * @skb: packet to process
3764 * This function calculates the checksum over the entire packet plus
3765 * the value of skb->csum. The latter can be used to supply the
3766 * checksum of a pseudo header as used by TCP/UDP. It returns the
3769 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
3770 * this function can be used to verify that checksum on received
3771 * packets. In that case the function should return zero if the
3772 * checksum is correct. In particular, this function will return zero
3773 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3774 * hardware has already verified the correctness of the checksum.
3776 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3778 return skb_csum_unnecessary(skb) ?
3779 0 : __skb_checksum_complete(skb);
3782 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3784 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3785 if (skb->csum_level == 0)
3786 skb->ip_summed = CHECKSUM_NONE;
3792 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3794 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3795 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3797 } else if (skb->ip_summed == CHECKSUM_NONE) {
3798 skb->ip_summed = CHECKSUM_UNNECESSARY;
3799 skb->csum_level = 0;
3803 /* Check if we need to perform checksum complete validation.
3805 * Returns true if checksum complete is needed, false otherwise
3806 * (either checksum is unnecessary or zero checksum is allowed).
3808 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3812 if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3813 skb->csum_valid = 1;
3814 __skb_decr_checksum_unnecessary(skb);
3821 /* For small packets <= CHECKSUM_BREAK perform checksum complete directly
3824 #define CHECKSUM_BREAK 76
3826 /* Unset checksum-complete
3828 * Unset checksum complete can be done when packet is being modified
3829 * (uncompressed for instance) and checksum-complete value is
3832 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3834 if (skb->ip_summed == CHECKSUM_COMPLETE)
3835 skb->ip_summed = CHECKSUM_NONE;
3838 /* Validate (init) checksum based on checksum complete.
3841 * 0: checksum is validated or try to in skb_checksum_complete. In the latter
3842 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3843 * checksum is stored in skb->csum for use in __skb_checksum_complete
3844 * non-zero: value of invalid checksum
3847 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3851 if (skb->ip_summed == CHECKSUM_COMPLETE) {
3852 if (!csum_fold(csum_add(psum, skb->csum))) {
3853 skb->csum_valid = 1;
3860 if (complete || skb->len <= CHECKSUM_BREAK) {
3863 csum = __skb_checksum_complete(skb);
3864 skb->csum_valid = !csum;
3871 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3876 /* Perform checksum validate (init). Note that this is a macro since we only
3877 * want to calculate the pseudo header which is an input function if necessary.
3878 * First we try to validate without any computation (checksum unnecessary) and
3879 * then calculate based on checksum complete calling the function to compute
3883 * 0: checksum is validated or try to in skb_checksum_complete
3884 * non-zero: value of invalid checksum
3886 #define __skb_checksum_validate(skb, proto, complete, \
3887 zero_okay, check, compute_pseudo) \
3889 __sum16 __ret = 0; \
3890 skb->csum_valid = 0; \
3891 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
3892 __ret = __skb_checksum_validate_complete(skb, \
3893 complete, compute_pseudo(skb, proto)); \
3897 #define skb_checksum_init(skb, proto, compute_pseudo) \
3898 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3900 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3901 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3903 #define skb_checksum_validate(skb, proto, compute_pseudo) \
3904 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3906 #define skb_checksum_validate_zero_check(skb, proto, check, \
3908 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3910 #define skb_checksum_simple_validate(skb) \
3911 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3913 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3915 return (skb->ip_summed == CHECKSUM_NONE && skb->csum_valid);
3918 static inline void __skb_checksum_convert(struct sk_buff *skb,
3919 __sum16 check, __wsum pseudo)
3921 skb->csum = ~pseudo;
3922 skb->ip_summed = CHECKSUM_COMPLETE;
3925 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo) \
3927 if (__skb_checksum_convert_check(skb)) \
3928 __skb_checksum_convert(skb, check, \
3929 compute_pseudo(skb, proto)); \
3932 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3933 u16 start, u16 offset)
3935 skb->ip_summed = CHECKSUM_PARTIAL;
3936 skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3937 skb->csum_offset = offset - start;
3940 /* Update skbuf and packet to reflect the remote checksum offload operation.
3941 * When called, ptr indicates the starting point for skb->csum when
3942 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3943 * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3945 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3946 int start, int offset, bool nopartial)
3951 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3955 if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3956 __skb_checksum_complete(skb);
3957 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3960 delta = remcsum_adjust(ptr, skb->csum, start, offset);
3962 /* Adjust skb->csum since we changed the packet */
3963 skb->csum = csum_add(skb->csum, delta);
3966 static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb)
3968 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3969 return (void *)(skb->_nfct & SKB_NFCT_PTRMASK);
3975 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3976 void nf_conntrack_destroy(struct nf_conntrack *nfct);
3977 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3979 if (nfct && atomic_dec_and_test(&nfct->use))
3980 nf_conntrack_destroy(nfct);
3982 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3985 atomic_inc(&nfct->use);
3989 #ifdef CONFIG_SKB_EXTENSIONS
3991 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3997 SKB_EXT_NUM, /* must be last */
4001 * struct skb_ext - sk_buff extensions
4002 * @refcnt: 1 on allocation, deallocated on 0
4003 * @offset: offset to add to @data to obtain extension address
4004 * @chunks: size currently allocated, stored in SKB_EXT_ALIGN_SHIFT units
4005 * @data: start of extension data, variable sized
4007 * Note: offsets/lengths are stored in chunks of 8 bytes, this allows
4008 * to use 'u8' types while allowing up to 2kb worth of extension data.
4012 u8 offset[SKB_EXT_NUM]; /* in chunks of 8 bytes */
4013 u8 chunks; /* same */
4014 char data[0] __aligned(8);
4017 void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id);
4018 void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id);
4019 void __skb_ext_put(struct skb_ext *ext);
4021 static inline void skb_ext_put(struct sk_buff *skb)
4023 if (skb->active_extensions)
4024 __skb_ext_put(skb->extensions);
4027 static inline void __skb_ext_copy(struct sk_buff *dst,
4028 const struct sk_buff *src)
4030 dst->active_extensions = src->active_extensions;
4032 if (src->active_extensions) {
4033 struct skb_ext *ext = src->extensions;
4035 refcount_inc(&ext->refcnt);
4036 dst->extensions = ext;
4040 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src)
4043 __skb_ext_copy(dst, src);
4046 static inline bool __skb_ext_exist(const struct skb_ext *ext, enum skb_ext_id i)
4048 return !!ext->offset[i];
4051 static inline bool skb_ext_exist(const struct sk_buff *skb, enum skb_ext_id id)
4053 return skb->active_extensions & (1 << id);
4056 static inline void skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
4058 if (skb_ext_exist(skb, id))
4059 __skb_ext_del(skb, id);
4062 static inline void *skb_ext_find(const struct sk_buff *skb, enum skb_ext_id id)
4064 if (skb_ext_exist(skb, id)) {
4065 struct skb_ext *ext = skb->extensions;
4067 return (void *)ext + (ext->offset[id] << 3);
4073 static inline void skb_ext_put(struct sk_buff *skb) {}
4074 static inline void skb_ext_del(struct sk_buff *skb, int unused) {}
4075 static inline void __skb_ext_copy(struct sk_buff *d, const struct sk_buff *s) {}
4076 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *s) {}
4077 #endif /* CONFIG_SKB_EXTENSIONS */
4079 static inline void nf_reset(struct sk_buff *skb)
4081 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4082 nf_conntrack_put(skb_nfct(skb));
4085 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4086 skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
4090 static inline void nf_reset_trace(struct sk_buff *skb)
4092 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
4097 static inline void ipvs_reset(struct sk_buff *skb)
4099 #if IS_ENABLED(CONFIG_IP_VS)
4100 skb->ipvs_property = 0;
4104 /* Note: This doesn't put any conntrack info in dst. */
4105 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
4108 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4109 dst->_nfct = src->_nfct;
4110 nf_conntrack_get(skb_nfct(src));
4112 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
4114 dst->nf_trace = src->nf_trace;
4118 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
4120 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4121 nf_conntrack_put(skb_nfct(dst));
4123 __nf_copy(dst, src, true);
4126 #ifdef CONFIG_NETWORK_SECMARK
4127 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
4129 to->secmark = from->secmark;
4132 static inline void skb_init_secmark(struct sk_buff *skb)
4137 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
4140 static inline void skb_init_secmark(struct sk_buff *skb)
4144 static inline int secpath_exists(const struct sk_buff *skb)
4147 return skb_ext_exist(skb, SKB_EXT_SEC_PATH);
4153 static inline bool skb_irq_freeable(const struct sk_buff *skb)
4155 return !skb->destructor &&
4156 !secpath_exists(skb) &&
4158 !skb->_skb_refdst &&
4159 !skb_has_frag_list(skb);
4162 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
4164 skb->queue_mapping = queue_mapping;
4167 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
4169 return skb->queue_mapping;
4172 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
4174 to->queue_mapping = from->queue_mapping;
4177 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
4179 skb->queue_mapping = rx_queue + 1;
4182 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
4184 return skb->queue_mapping - 1;
4187 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
4189 return skb->queue_mapping != 0;
4192 static inline void skb_set_dst_pending_confirm(struct sk_buff *skb, u32 val)
4194 skb->dst_pending_confirm = val;
4197 static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb)
4199 return skb->dst_pending_confirm != 0;
4202 static inline struct sec_path *skb_sec_path(const struct sk_buff *skb)
4205 return skb_ext_find(skb, SKB_EXT_SEC_PATH);
4211 /* Keeps track of mac header offset relative to skb->head.
4212 * It is useful for TSO of Tunneling protocol. e.g. GRE.
4213 * For non-tunnel skb it points to skb_mac_header() and for
4214 * tunnel skb it points to outer mac header.
4215 * Keeps track of level of encapsulation of network headers.
4226 #define SKB_SGO_CB_OFFSET 32
4227 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
4229 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
4231 return (skb_mac_header(inner_skb) - inner_skb->head) -
4232 SKB_GSO_CB(inner_skb)->mac_offset;
4235 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
4237 int new_headroom, headroom;
4240 headroom = skb_headroom(skb);
4241 ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
4245 new_headroom = skb_headroom(skb);
4246 SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
4250 static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
4252 /* Do not update partial checksums if remote checksum is enabled. */
4253 if (skb->remcsum_offload)
4256 SKB_GSO_CB(skb)->csum = res;
4257 SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
4260 /* Compute the checksum for a gso segment. First compute the checksum value
4261 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
4262 * then add in skb->csum (checksum from csum_start to end of packet).
4263 * skb->csum and csum_start are then updated to reflect the checksum of the
4264 * resultant packet starting from the transport header-- the resultant checksum
4265 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
4268 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
4270 unsigned char *csum_start = skb_transport_header(skb);
4271 int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
4272 __wsum partial = SKB_GSO_CB(skb)->csum;
4274 SKB_GSO_CB(skb)->csum = res;
4275 SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
4277 return csum_fold(csum_partial(csum_start, plen, partial));
4280 static inline bool skb_is_gso(const struct sk_buff *skb)
4282 return skb_shinfo(skb)->gso_size;
4285 /* Note: Should be called only if skb_is_gso(skb) is true */
4286 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
4288 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
4291 /* Note: Should be called only if skb_is_gso(skb) is true */
4292 static inline bool skb_is_gso_sctp(const struct sk_buff *skb)
4294 return skb_shinfo(skb)->gso_type & SKB_GSO_SCTP;
4297 /* Note: Should be called only if skb_is_gso(skb) is true */
4298 static inline bool skb_is_gso_tcp(const struct sk_buff *skb)
4300 return skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6);
4303 static inline void skb_gso_reset(struct sk_buff *skb)
4305 skb_shinfo(skb)->gso_size = 0;
4306 skb_shinfo(skb)->gso_segs = 0;
4307 skb_shinfo(skb)->gso_type = 0;
4310 static inline void skb_increase_gso_size(struct skb_shared_info *shinfo,
4313 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
4315 shinfo->gso_size += increment;
4318 static inline void skb_decrease_gso_size(struct skb_shared_info *shinfo,
4321 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
4323 shinfo->gso_size -= decrement;
4326 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
4328 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
4330 /* LRO sets gso_size but not gso_type, whereas if GSO is really
4331 * wanted then gso_type will be set. */
4332 const struct skb_shared_info *shinfo = skb_shinfo(skb);
4334 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
4335 unlikely(shinfo->gso_type == 0)) {
4336 __skb_warn_lro_forwarding(skb);
4342 static inline void skb_forward_csum(struct sk_buff *skb)
4344 /* Unfortunately we don't support this one. Any brave souls? */
4345 if (skb->ip_summed == CHECKSUM_COMPLETE)
4346 skb->ip_summed = CHECKSUM_NONE;
4350 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
4351 * @skb: skb to check
4353 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
4354 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
4355 * use this helper, to document places where we make this assertion.
4357 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
4360 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
4364 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
4366 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
4367 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
4368 unsigned int transport_len,
4369 __sum16(*skb_chkf)(struct sk_buff *skb));
4372 * skb_head_is_locked - Determine if the skb->head is locked down
4373 * @skb: skb to check
4375 * The head on skbs build around a head frag can be removed if they are
4376 * not cloned. This function returns true if the skb head is locked down
4377 * due to either being allocated via kmalloc, or by being a clone with
4378 * multiple references to the head.
4380 static inline bool skb_head_is_locked(const struct sk_buff *skb)
4382 return !skb->head_frag || skb_cloned(skb);
4385 /* Local Checksum Offload.
4386 * Compute outer checksum based on the assumption that the
4387 * inner checksum will be offloaded later.
4388 * See Documentation/networking/checksum-offloads.rst for
4389 * explanation of how this works.
4390 * Fill in outer checksum adjustment (e.g. with sum of outer
4391 * pseudo-header) before calling.
4392 * Also ensure that inner checksum is in linear data area.
4394 static inline __wsum lco_csum(struct sk_buff *skb)
4396 unsigned char *csum_start = skb_checksum_start(skb);
4397 unsigned char *l4_hdr = skb_transport_header(skb);
4400 /* Start with complement of inner checksum adjustment */
4401 partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
4404 /* Add in checksum of our headers (incl. outer checksum
4405 * adjustment filled in by caller) and return result.
4407 return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
4410 #endif /* __KERNEL__ */
4411 #endif /* _LINUX_SKBUFF_H */