1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Definitions for the 'struct sk_buff' memory handlers.
6 * Alan Cox, <gw4pts@gw4pts.ampr.org>
7 * Florian La Roche, <rzsfl@rz.uni-sb.de>
10 #ifndef _LINUX_SKBUFF_H
11 #define _LINUX_SKBUFF_H
13 #include <linux/kernel.h>
14 #include <linux/compiler.h>
15 #include <linux/time.h>
16 #include <linux/bug.h>
17 #include <linux/bvec.h>
18 #include <linux/cache.h>
19 #include <linux/rbtree.h>
20 #include <linux/socket.h>
21 #include <linux/refcount.h>
23 #include <linux/atomic.h>
24 #include <asm/types.h>
25 #include <linux/spinlock.h>
26 #include <linux/net.h>
27 #include <linux/textsearch.h>
28 #include <net/checksum.h>
29 #include <linux/rcupdate.h>
30 #include <linux/hrtimer.h>
31 #include <linux/dma-mapping.h>
32 #include <linux/netdev_features.h>
33 #include <linux/sched.h>
34 #include <linux/sched/clock.h>
35 #include <net/flow_dissector.h>
36 #include <linux/splice.h>
37 #include <linux/in6.h>
38 #include <linux/if_packet.h>
40 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
41 #include <linux/netfilter/nf_conntrack_common.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 IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
251 struct nf_bridge_info {
253 BRNF_PROTO_UNCHANGED,
261 struct net_device *physindev;
263 /* always valid & non-NULL from FORWARD on, for physdev match */
264 struct net_device *physoutdev;
266 /* prerouting: detect dnat in orig/reply direction */
268 struct in6_addr ipv6_daddr;
270 /* after prerouting + nat detected: store original source
271 * mac since neigh resolution overwrites it, only used while
272 * skb is out in neigh layer.
274 char neigh_header[8];
279 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
280 /* Chain in tc_skb_ext will be used to share the tc chain with
281 * ovs recirc_id. It will be set to the current chain by tc
282 * and read by ovs to recirc_id.
289 struct sk_buff_head {
290 /* These two members must be first. */
291 struct sk_buff *next;
292 struct sk_buff *prev;
300 /* To allow 64K frame to be packed as single skb without frag_list we
301 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
302 * buffers which do not start on a page boundary.
304 * Since GRO uses frags we allocate at least 16 regardless of page
307 #if (65536/PAGE_SIZE + 1) < 16
308 #define MAX_SKB_FRAGS 16UL
310 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
312 extern int sysctl_max_skb_frags;
314 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
315 * segment using its current segmentation instead.
317 #define GSO_BY_FRAGS 0xFFFF
319 typedef struct bio_vec skb_frag_t;
322 * skb_frag_size() - Returns the size of a skb fragment
323 * @frag: skb fragment
325 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
331 * skb_frag_size_set() - Sets the size of a skb fragment
332 * @frag: skb fragment
333 * @size: size of fragment
335 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
341 * skb_frag_size_add() - Increments the size of a skb fragment by @delta
342 * @frag: skb fragment
343 * @delta: value to add
345 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
347 frag->bv_len += delta;
351 * skb_frag_size_sub() - Decrements the size of a skb fragment by @delta
352 * @frag: skb fragment
353 * @delta: value to subtract
355 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
357 frag->bv_len -= delta;
361 * skb_frag_must_loop - Test if %p is a high memory page
362 * @p: fragment's page
364 static inline bool skb_frag_must_loop(struct page *p)
366 #if defined(CONFIG_HIGHMEM)
374 * skb_frag_foreach_page - loop over pages in a fragment
376 * @f: skb frag to operate on
377 * @f_off: offset from start of f->bv_page
378 * @f_len: length from f_off to loop over
379 * @p: (temp var) current page
380 * @p_off: (temp var) offset from start of current page,
381 * non-zero only on first page.
382 * @p_len: (temp var) length in current page,
383 * < PAGE_SIZE only on first and last page.
384 * @copied: (temp var) length so far, excluding current p_len.
386 * A fragment can hold a compound page, in which case per-page
387 * operations, notably kmap_atomic, must be called for each
390 #define skb_frag_foreach_page(f, f_off, f_len, p, p_off, p_len, copied) \
391 for (p = skb_frag_page(f) + ((f_off) >> PAGE_SHIFT), \
392 p_off = (f_off) & (PAGE_SIZE - 1), \
393 p_len = skb_frag_must_loop(p) ? \
394 min_t(u32, f_len, PAGE_SIZE - p_off) : f_len, \
397 copied += p_len, p++, p_off = 0, \
398 p_len = min_t(u32, f_len - copied, PAGE_SIZE)) \
400 #define HAVE_HW_TIME_STAMP
403 * struct skb_shared_hwtstamps - hardware time stamps
404 * @hwtstamp: hardware time stamp transformed into duration
405 * since arbitrary point in time
407 * Software time stamps generated by ktime_get_real() are stored in
410 * hwtstamps can only be compared against other hwtstamps from
413 * This structure is attached to packets as part of the
414 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
416 struct skb_shared_hwtstamps {
420 /* Definitions for tx_flags in struct skb_shared_info */
422 /* generate hardware time stamp */
423 SKBTX_HW_TSTAMP = 1 << 0,
425 /* generate software time stamp when queueing packet to NIC */
426 SKBTX_SW_TSTAMP = 1 << 1,
428 /* device driver is going to provide hardware time stamp */
429 SKBTX_IN_PROGRESS = 1 << 2,
431 /* device driver supports TX zero-copy buffers */
432 SKBTX_DEV_ZEROCOPY = 1 << 3,
434 /* generate wifi status information (where possible) */
435 SKBTX_WIFI_STATUS = 1 << 4,
437 /* This indicates at least one fragment might be overwritten
438 * (as in vmsplice(), sendfile() ...)
439 * If we need to compute a TX checksum, we'll need to copy
440 * all frags to avoid possible bad checksum
442 SKBTX_SHARED_FRAG = 1 << 5,
444 /* generate software time stamp when entering packet scheduling */
445 SKBTX_SCHED_TSTAMP = 1 << 6,
448 #define SKBTX_ZEROCOPY_FRAG (SKBTX_DEV_ZEROCOPY | SKBTX_SHARED_FRAG)
449 #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
451 #define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
454 * The callback notifies userspace to release buffers when skb DMA is done in
455 * lower device, the skb last reference should be 0 when calling this.
456 * The zerocopy_success argument is true if zero copy transmit occurred,
457 * false on data copy or out of memory error caused by data copy attempt.
458 * The ctx field is used to track device context.
459 * The desc field is used to track userspace buffer index.
462 void (*callback)(struct ubuf_info *, bool zerocopy_success);
478 struct user_struct *user;
483 #define skb_uarg(SKB) ((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg))
485 int mm_account_pinned_pages(struct mmpin *mmp, size_t size);
486 void mm_unaccount_pinned_pages(struct mmpin *mmp);
488 struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size);
489 struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size,
490 struct ubuf_info *uarg);
492 static inline void sock_zerocopy_get(struct ubuf_info *uarg)
494 refcount_inc(&uarg->refcnt);
497 void sock_zerocopy_put(struct ubuf_info *uarg);
498 void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
500 void sock_zerocopy_callback(struct ubuf_info *uarg, bool success);
502 int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len);
503 int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
504 struct msghdr *msg, int len,
505 struct ubuf_info *uarg);
507 /* This data is invariant across clones and lives at
508 * the end of the header data, ie. at skb->end.
510 struct skb_shared_info {
515 unsigned short gso_size;
516 /* Warning: this field is not always filled in (UFO)! */
517 unsigned short gso_segs;
518 struct sk_buff *frag_list;
519 struct skb_shared_hwtstamps hwtstamps;
520 unsigned int gso_type;
524 * Warning : all fields before dataref are cleared in __alloc_skb()
528 /* Intermediate layers must ensure that destructor_arg
529 * remains valid until skb destructor */
530 void * destructor_arg;
532 /* must be last field, see pskb_expand_head() */
533 skb_frag_t frags[MAX_SKB_FRAGS];
536 /* We divide dataref into two halves. The higher 16 bits hold references
537 * to the payload part of skb->data. The lower 16 bits hold references to
538 * the entire skb->data. A clone of a headerless skb holds the length of
539 * the header in skb->hdr_len.
541 * All users must obey the rule that the skb->data reference count must be
542 * greater than or equal to the payload reference count.
544 * Holding a reference to the payload part means that the user does not
545 * care about modifications to the header part of skb->data.
547 #define SKB_DATAREF_SHIFT 16
548 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
552 SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
553 SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */
554 SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */
558 SKB_GSO_TCPV4 = 1 << 0,
560 /* This indicates the skb is from an untrusted source. */
561 SKB_GSO_DODGY = 1 << 1,
563 /* This indicates the tcp segment has CWR set. */
564 SKB_GSO_TCP_ECN = 1 << 2,
566 SKB_GSO_TCP_FIXEDID = 1 << 3,
568 SKB_GSO_TCPV6 = 1 << 4,
570 SKB_GSO_FCOE = 1 << 5,
572 SKB_GSO_GRE = 1 << 6,
574 SKB_GSO_GRE_CSUM = 1 << 7,
576 SKB_GSO_IPXIP4 = 1 << 8,
578 SKB_GSO_IPXIP6 = 1 << 9,
580 SKB_GSO_UDP_TUNNEL = 1 << 10,
582 SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
584 SKB_GSO_PARTIAL = 1 << 12,
586 SKB_GSO_TUNNEL_REMCSUM = 1 << 13,
588 SKB_GSO_SCTP = 1 << 14,
590 SKB_GSO_ESP = 1 << 15,
592 SKB_GSO_UDP = 1 << 16,
594 SKB_GSO_UDP_L4 = 1 << 17,
597 #if BITS_PER_LONG > 32
598 #define NET_SKBUFF_DATA_USES_OFFSET 1
601 #ifdef NET_SKBUFF_DATA_USES_OFFSET
602 typedef unsigned int sk_buff_data_t;
604 typedef unsigned char *sk_buff_data_t;
608 * struct sk_buff - socket buffer
609 * @next: Next buffer in list
610 * @prev: Previous buffer in list
611 * @tstamp: Time we arrived/left
612 * @rbnode: RB tree node, alternative to next/prev for netem/tcp
613 * @sk: Socket we are owned by
614 * @dev: Device we arrived on/are leaving by
615 * @cb: Control buffer. Free for use by every layer. Put private vars here
616 * @_skb_refdst: destination entry (with norefcount bit)
617 * @sp: the security path, used for xfrm
618 * @len: Length of actual data
619 * @data_len: Data length
620 * @mac_len: Length of link layer header
621 * @hdr_len: writable header length of cloned skb
622 * @csum: Checksum (must include start/offset pair)
623 * @csum_start: Offset from skb->head where checksumming should start
624 * @csum_offset: Offset from csum_start where checksum should be stored
625 * @priority: Packet queueing priority
626 * @ignore_df: allow local fragmentation
627 * @cloned: Head may be cloned (check refcnt to be sure)
628 * @ip_summed: Driver fed us an IP checksum
629 * @nohdr: Payload reference only, must not modify header
630 * @pkt_type: Packet class
631 * @fclone: skbuff clone status
632 * @ipvs_property: skbuff is owned by ipvs
633 * @offload_fwd_mark: Packet was L2-forwarded in hardware
634 * @offload_l3_fwd_mark: Packet was L3-forwarded in hardware
635 * @tc_skip_classify: do not classify packet. set by IFB device
636 * @tc_at_ingress: used within tc_classify to distinguish in/egress
637 * @tc_redirected: packet was redirected by a tc action
638 * @tc_from_ingress: if tc_redirected, tc_at_ingress at time of redirect
639 * @peeked: this packet has been seen already, so stats have been
640 * done for it, don't do them again
641 * @nf_trace: netfilter packet trace flag
642 * @protocol: Packet protocol from driver
643 * @destructor: Destruct function
644 * @tcp_tsorted_anchor: list structure for TCP (tp->tsorted_sent_queue)
645 * @_nfct: Associated connection, if any (with nfctinfo bits)
646 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
647 * @skb_iif: ifindex of device we arrived on
648 * @tc_index: Traffic control index
649 * @hash: the packet hash
650 * @queue_mapping: Queue mapping for multiqueue devices
651 * @pfmemalloc: skbuff was allocated from PFMEMALLOC reserves
652 * @active_extensions: active extensions (skb_ext_id types)
653 * @ndisc_nodetype: router type (from link layer)
654 * @ooo_okay: allow the mapping of a socket to a queue to be changed
655 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport
657 * @sw_hash: indicates hash was computed in software stack
658 * @wifi_acked_valid: wifi_acked was set
659 * @wifi_acked: whether frame was acked on wifi or not
660 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
661 * @csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL
662 * @dst_pending_confirm: need to confirm neighbour
663 * @decrypted: Decrypted SKB
664 * @napi_id: id of the NAPI struct this skb came from
665 * @secmark: security marking
666 * @mark: Generic packet mark
667 * @vlan_proto: vlan encapsulation protocol
668 * @vlan_tci: vlan tag control information
669 * @inner_protocol: Protocol (encapsulation)
670 * @inner_transport_header: Inner transport layer header (encapsulation)
671 * @inner_network_header: Network layer header (encapsulation)
672 * @inner_mac_header: Link layer header (encapsulation)
673 * @transport_header: Transport layer header
674 * @network_header: Network layer header
675 * @mac_header: Link layer header
676 * @tail: Tail pointer
678 * @head: Head of buffer
679 * @data: Data head pointer
680 * @truesize: Buffer size
681 * @users: User count - see {datagram,tcp}.c
682 * @extensions: allocated extensions, valid if active_extensions is nonzero
688 /* These two members must be first. */
689 struct sk_buff *next;
690 struct sk_buff *prev;
693 struct net_device *dev;
694 /* Some protocols might use this space to store information,
695 * while device pointer would be NULL.
696 * UDP receive path is one user.
698 unsigned long dev_scratch;
701 struct rb_node rbnode; /* used in netem, ip4 defrag, and tcp stack */
702 struct list_head list;
707 int ip_defrag_offset;
712 u64 skb_mstamp_ns; /* earliest departure time */
715 * This is the control buffer. It is free to use for every
716 * layer. Please put your private variables there. If you
717 * want to keep them across layers you have to do a skb_clone()
718 * first. This is owned by whoever has the skb queued ATM.
720 char cb[48] __aligned(8);
724 unsigned long _skb_refdst;
725 void (*destructor)(struct sk_buff *skb);
727 struct list_head tcp_tsorted_anchor;
730 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
738 /* Following fields are _not_ copied in __copy_skb_header()
739 * Note that queue_mapping is here mostly to fill a hole.
743 /* if you move cloned around you also must adapt those constants */
744 #ifdef __BIG_ENDIAN_BITFIELD
745 #define CLONED_MASK (1 << 7)
747 #define CLONED_MASK 1
749 #define CLONED_OFFSET() offsetof(struct sk_buff, __cloned_offset)
751 __u8 __cloned_offset[0];
758 #ifdef CONFIG_SKB_EXTENSIONS
759 __u8 active_extensions;
761 /* fields enclosed in headers_start/headers_end are copied
762 * using a single memcpy() in __copy_skb_header()
765 __u32 headers_start[0];
768 /* if you move pkt_type around you also must adapt those constants */
769 #ifdef __BIG_ENDIAN_BITFIELD
770 #define PKT_TYPE_MAX (7 << 5)
772 #define PKT_TYPE_MAX 7
774 #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
776 __u8 __pkt_type_offset[0];
785 __u8 wifi_acked_valid:1;
788 /* Indicates the inner headers are valid in the skbuff. */
789 __u8 encapsulation:1;
790 __u8 encap_hdr_csum:1;
793 #ifdef __BIG_ENDIAN_BITFIELD
794 #define PKT_VLAN_PRESENT_BIT 7
796 #define PKT_VLAN_PRESENT_BIT 0
798 #define PKT_VLAN_PRESENT_OFFSET() offsetof(struct sk_buff, __pkt_vlan_present_offset)
799 __u8 __pkt_vlan_present_offset[0];
801 __u8 csum_complete_sw:1;
803 __u8 csum_not_inet:1;
804 __u8 dst_pending_confirm:1;
805 #ifdef CONFIG_IPV6_NDISC_NODETYPE
806 __u8 ndisc_nodetype:2;
809 __u8 ipvs_property:1;
810 __u8 inner_protocol_type:1;
811 __u8 remcsum_offload:1;
812 #ifdef CONFIG_NET_SWITCHDEV
813 __u8 offload_fwd_mark:1;
814 __u8 offload_l3_fwd_mark:1;
816 #ifdef CONFIG_NET_CLS_ACT
817 __u8 tc_skip_classify:1;
818 __u8 tc_at_ingress:1;
819 __u8 tc_redirected:1;
820 __u8 tc_from_ingress:1;
822 #ifdef CONFIG_TLS_DEVICE
826 #ifdef CONFIG_NET_SCHED
827 __u16 tc_index; /* traffic control index */
842 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
844 unsigned int napi_id;
845 unsigned int sender_cpu;
848 #ifdef CONFIG_NETWORK_SECMARK
854 __u32 reserved_tailroom;
858 __be16 inner_protocol;
862 __u16 inner_transport_header;
863 __u16 inner_network_header;
864 __u16 inner_mac_header;
867 __u16 transport_header;
868 __u16 network_header;
872 __u32 headers_end[0];
875 /* These elements must be at the end, see alloc_skb() for details. */
880 unsigned int truesize;
883 #ifdef CONFIG_SKB_EXTENSIONS
884 /* only useable after checking ->active_extensions != 0 */
885 struct skb_ext *extensions;
891 * Handling routines are only of interest to the kernel
894 #define SKB_ALLOC_FCLONE 0x01
895 #define SKB_ALLOC_RX 0x02
896 #define SKB_ALLOC_NAPI 0x04
899 * skb_pfmemalloc - Test if the skb was allocated from PFMEMALLOC reserves
902 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
904 return unlikely(skb->pfmemalloc);
908 * skb might have a dst pointer attached, refcounted or not.
909 * _skb_refdst low order bit is set if refcount was _not_ taken
911 #define SKB_DST_NOREF 1UL
912 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
915 * skb_dst - returns skb dst_entry
918 * Returns skb dst_entry, regardless of reference taken or not.
920 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
922 /* If refdst was not refcounted, check we still are in a
923 * rcu_read_lock section
925 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
926 !rcu_read_lock_held() &&
927 !rcu_read_lock_bh_held());
928 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
932 * skb_dst_set - sets skb dst
936 * Sets skb dst, assuming a reference was taken on dst and should
937 * be released by skb_dst_drop()
939 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
941 skb->_skb_refdst = (unsigned long)dst;
945 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
949 * Sets skb dst, assuming a reference was not taken on dst.
950 * If dst entry is cached, we do not take reference and dst_release
951 * will be avoided by refdst_drop. If dst entry is not cached, we take
952 * reference, so that last dst_release can destroy the dst immediately.
954 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
956 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
957 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
961 * skb_dst_is_noref - Test if skb dst isn't refcounted
964 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
966 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
970 * skb_rtable - Returns the skb &rtable
973 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
975 return (struct rtable *)skb_dst(skb);
978 /* For mangling skb->pkt_type from user space side from applications
979 * such as nft, tc, etc, we only allow a conservative subset of
980 * possible pkt_types to be set.
982 static inline bool skb_pkt_type_ok(u32 ptype)
984 return ptype <= PACKET_OTHERHOST;
988 * skb_napi_id - Returns the skb's NAPI id
991 static inline unsigned int skb_napi_id(const struct sk_buff *skb)
993 #ifdef CONFIG_NET_RX_BUSY_POLL
1001 * skb_unref - decrement the skb's reference count
1004 * Returns true if we can free the skb.
1006 static inline bool skb_unref(struct sk_buff *skb)
1010 if (likely(refcount_read(&skb->users) == 1))
1012 else if (likely(!refcount_dec_and_test(&skb->users)))
1018 void skb_release_head_state(struct sk_buff *skb);
1019 void kfree_skb(struct sk_buff *skb);
1020 void kfree_skb_list(struct sk_buff *segs);
1021 void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt);
1022 void skb_tx_error(struct sk_buff *skb);
1023 void consume_skb(struct sk_buff *skb);
1024 void __consume_stateless_skb(struct sk_buff *skb);
1025 void __kfree_skb(struct sk_buff *skb);
1026 extern struct kmem_cache *skbuff_head_cache;
1028 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
1029 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
1030 bool *fragstolen, int *delta_truesize);
1032 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
1034 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
1035 struct sk_buff *build_skb(void *data, unsigned int frag_size);
1036 struct sk_buff *build_skb_around(struct sk_buff *skb,
1037 void *data, unsigned int frag_size);
1040 * alloc_skb - allocate a network buffer
1041 * @size: size to allocate
1042 * @priority: allocation mask
1044 * This function is a convenient wrapper around __alloc_skb().
1046 static inline struct sk_buff *alloc_skb(unsigned int size,
1049 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
1052 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
1053 unsigned long data_len,
1057 struct sk_buff *alloc_skb_for_msg(struct sk_buff *first);
1059 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
1060 struct sk_buff_fclones {
1061 struct sk_buff skb1;
1063 struct sk_buff skb2;
1065 refcount_t fclone_ref;
1069 * skb_fclone_busy - check if fclone is busy
1073 * Returns true if skb is a fast clone, and its clone is not freed.
1074 * Some drivers call skb_orphan() in their ndo_start_xmit(),
1075 * so we also check that this didnt happen.
1077 static inline bool skb_fclone_busy(const struct sock *sk,
1078 const struct sk_buff *skb)
1080 const struct sk_buff_fclones *fclones;
1082 fclones = container_of(skb, struct sk_buff_fclones, skb1);
1084 return skb->fclone == SKB_FCLONE_ORIG &&
1085 refcount_read(&fclones->fclone_ref) > 1 &&
1086 fclones->skb2.sk == sk;
1090 * alloc_skb_fclone - allocate a network buffer from fclone cache
1091 * @size: size to allocate
1092 * @priority: allocation mask
1094 * This function is a convenient wrapper around __alloc_skb().
1096 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
1099 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
1102 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
1103 void skb_headers_offset_update(struct sk_buff *skb, int off);
1104 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
1105 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
1106 void skb_copy_header(struct sk_buff *new, const struct sk_buff *old);
1107 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
1108 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1109 gfp_t gfp_mask, bool fclone);
1110 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
1113 return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
1116 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
1117 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
1118 unsigned int headroom);
1119 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
1120 int newtailroom, gfp_t priority);
1121 int __must_check skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
1122 int offset, int len);
1123 int __must_check skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg,
1124 int offset, int len);
1125 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
1126 int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error);
1129 * skb_pad - zero pad the tail of an skb
1130 * @skb: buffer to pad
1131 * @pad: space to pad
1133 * Ensure that a buffer is followed by a padding area that is zero
1134 * filled. Used by network drivers which may DMA or transfer data
1135 * beyond the buffer end onto the wire.
1137 * May return error in out of memory cases. The skb is freed on error.
1139 static inline int skb_pad(struct sk_buff *skb, int pad)
1141 return __skb_pad(skb, pad, true);
1143 #define dev_kfree_skb(a) consume_skb(a)
1145 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1146 int offset, size_t size);
1148 struct skb_seq_state {
1152 __u32 stepped_offset;
1153 struct sk_buff *root_skb;
1154 struct sk_buff *cur_skb;
1158 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1159 unsigned int to, struct skb_seq_state *st);
1160 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1161 struct skb_seq_state *st);
1162 void skb_abort_seq_read(struct skb_seq_state *st);
1164 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1165 unsigned int to, struct ts_config *config);
1168 * Packet hash types specify the type of hash in skb_set_hash.
1170 * Hash types refer to the protocol layer addresses which are used to
1171 * construct a packet's hash. The hashes are used to differentiate or identify
1172 * flows of the protocol layer for the hash type. Hash types are either
1173 * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1175 * Properties of hashes:
1177 * 1) Two packets in different flows have different hash values
1178 * 2) Two packets in the same flow should have the same hash value
1180 * A hash at a higher layer is considered to be more specific. A driver should
1181 * set the most specific hash possible.
1183 * A driver cannot indicate a more specific hash than the layer at which a hash
1184 * was computed. For instance an L3 hash cannot be set as an L4 hash.
1186 * A driver may indicate a hash level which is less specific than the
1187 * actual layer the hash was computed on. For instance, a hash computed
1188 * at L4 may be considered an L3 hash. This should only be done if the
1189 * driver can't unambiguously determine that the HW computed the hash at
1190 * the higher layer. Note that the "should" in the second property above
1193 enum pkt_hash_types {
1194 PKT_HASH_TYPE_NONE, /* Undefined type */
1195 PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
1196 PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
1197 PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
1200 static inline void skb_clear_hash(struct sk_buff *skb)
1207 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1210 skb_clear_hash(skb);
1214 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1216 skb->l4_hash = is_l4;
1217 skb->sw_hash = is_sw;
1222 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1224 /* Used by drivers to set hash from HW */
1225 __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1229 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1231 __skb_set_hash(skb, hash, true, is_l4);
1234 void __skb_get_hash(struct sk_buff *skb);
1235 u32 __skb_get_hash_symmetric(const struct sk_buff *skb);
1236 u32 skb_get_poff(const struct sk_buff *skb);
1237 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1238 const struct flow_keys_basic *keys, int hlen);
1239 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1240 void *data, int hlen_proto);
1242 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1243 int thoff, u8 ip_proto)
1245 return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1248 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1249 const struct flow_dissector_key *key,
1250 unsigned int key_count);
1253 int skb_flow_dissector_prog_query(const union bpf_attr *attr,
1254 union bpf_attr __user *uattr);
1255 int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
1256 struct bpf_prog *prog);
1258 int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr);
1260 static inline int skb_flow_dissector_prog_query(const union bpf_attr *attr,
1261 union bpf_attr __user *uattr)
1266 static inline int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
1267 struct bpf_prog *prog)
1272 static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
1278 struct bpf_flow_dissector;
1279 bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
1280 __be16 proto, int nhoff, int hlen, unsigned int flags);
1282 bool __skb_flow_dissect(const struct net *net,
1283 const struct sk_buff *skb,
1284 struct flow_dissector *flow_dissector,
1285 void *target_container,
1286 void *data, __be16 proto, int nhoff, int hlen,
1287 unsigned int flags);
1289 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1290 struct flow_dissector *flow_dissector,
1291 void *target_container, unsigned int flags)
1293 return __skb_flow_dissect(NULL, skb, flow_dissector,
1294 target_container, NULL, 0, 0, 0, flags);
1297 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1298 struct flow_keys *flow,
1301 memset(flow, 0, sizeof(*flow));
1302 return __skb_flow_dissect(NULL, skb, &flow_keys_dissector,
1303 flow, NULL, 0, 0, 0, flags);
1307 skb_flow_dissect_flow_keys_basic(const struct net *net,
1308 const struct sk_buff *skb,
1309 struct flow_keys_basic *flow, void *data,
1310 __be16 proto, int nhoff, int hlen,
1313 memset(flow, 0, sizeof(*flow));
1314 return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow,
1315 data, proto, nhoff, hlen, flags);
1318 void skb_flow_dissect_meta(const struct sk_buff *skb,
1319 struct flow_dissector *flow_dissector,
1320 void *target_container);
1322 /* Gets a skb connection tracking info, ctinfo map should be a
1323 * a map of mapsize to translate enum ip_conntrack_info states
1327 skb_flow_dissect_ct(const struct sk_buff *skb,
1328 struct flow_dissector *flow_dissector,
1329 void *target_container,
1333 skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
1334 struct flow_dissector *flow_dissector,
1335 void *target_container);
1337 static inline __u32 skb_get_hash(struct sk_buff *skb)
1339 if (!skb->l4_hash && !skb->sw_hash)
1340 __skb_get_hash(skb);
1345 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1347 if (!skb->l4_hash && !skb->sw_hash) {
1348 struct flow_keys keys;
1349 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1351 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1357 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1359 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1364 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1366 to->hash = from->hash;
1367 to->sw_hash = from->sw_hash;
1368 to->l4_hash = from->l4_hash;
1371 static inline void skb_copy_decrypted(struct sk_buff *to,
1372 const struct sk_buff *from)
1374 #ifdef CONFIG_TLS_DEVICE
1375 to->decrypted = from->decrypted;
1379 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1380 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1382 return skb->head + skb->end;
1385 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1390 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1395 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1397 return skb->end - skb->head;
1402 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1404 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1406 return &skb_shinfo(skb)->hwtstamps;
1409 static inline struct ubuf_info *skb_zcopy(struct sk_buff *skb)
1411 bool is_zcopy = skb && skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY;
1413 return is_zcopy ? skb_uarg(skb) : NULL;
1416 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg,
1419 if (skb && uarg && !skb_zcopy(skb)) {
1420 if (unlikely(have_ref && *have_ref))
1423 sock_zerocopy_get(uarg);
1424 skb_shinfo(skb)->destructor_arg = uarg;
1425 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG;
1429 static inline void skb_zcopy_set_nouarg(struct sk_buff *skb, void *val)
1431 skb_shinfo(skb)->destructor_arg = (void *)((uintptr_t) val | 0x1UL);
1432 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG;
1435 static inline bool skb_zcopy_is_nouarg(struct sk_buff *skb)
1437 return (uintptr_t) skb_shinfo(skb)->destructor_arg & 0x1UL;
1440 static inline void *skb_zcopy_get_nouarg(struct sk_buff *skb)
1442 return (void *)((uintptr_t) skb_shinfo(skb)->destructor_arg & ~0x1UL);
1445 /* Release a reference on a zerocopy structure */
1446 static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
1448 struct ubuf_info *uarg = skb_zcopy(skb);
1451 if (skb_zcopy_is_nouarg(skb)) {
1452 /* no notification callback */
1453 } else if (uarg->callback == sock_zerocopy_callback) {
1454 uarg->zerocopy = uarg->zerocopy && zerocopy;
1455 sock_zerocopy_put(uarg);
1457 uarg->callback(uarg, zerocopy);
1460 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
1464 /* Abort a zerocopy operation and revert zckey on error in send syscall */
1465 static inline void skb_zcopy_abort(struct sk_buff *skb)
1467 struct ubuf_info *uarg = skb_zcopy(skb);
1470 sock_zerocopy_put_abort(uarg, false);
1471 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
1475 static inline void skb_mark_not_on_list(struct sk_buff *skb)
1480 static inline void skb_list_del_init(struct sk_buff *skb)
1482 __list_del_entry(&skb->list);
1483 skb_mark_not_on_list(skb);
1487 * skb_queue_empty - check if a queue is empty
1490 * Returns true if the queue is empty, false otherwise.
1492 static inline int skb_queue_empty(const struct sk_buff_head *list)
1494 return list->next == (const struct sk_buff *) list;
1498 * skb_queue_is_last - check if skb is the last entry in the queue
1502 * Returns true if @skb is the last buffer on the list.
1504 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1505 const struct sk_buff *skb)
1507 return skb->next == (const struct sk_buff *) list;
1511 * skb_queue_is_first - check if skb is the first entry in the queue
1515 * Returns true if @skb is the first buffer on the list.
1517 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1518 const struct sk_buff *skb)
1520 return skb->prev == (const struct sk_buff *) list;
1524 * skb_queue_next - return the next packet in the queue
1526 * @skb: current buffer
1528 * Return the next packet in @list after @skb. It is only valid to
1529 * call this if skb_queue_is_last() evaluates to false.
1531 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1532 const struct sk_buff *skb)
1534 /* This BUG_ON may seem severe, but if we just return then we
1535 * are going to dereference garbage.
1537 BUG_ON(skb_queue_is_last(list, skb));
1542 * skb_queue_prev - return the prev packet in the queue
1544 * @skb: current buffer
1546 * Return the prev packet in @list before @skb. It is only valid to
1547 * call this if skb_queue_is_first() evaluates to false.
1549 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1550 const struct sk_buff *skb)
1552 /* This BUG_ON may seem severe, but if we just return then we
1553 * are going to dereference garbage.
1555 BUG_ON(skb_queue_is_first(list, skb));
1560 * skb_get - reference buffer
1561 * @skb: buffer to reference
1563 * Makes another reference to a socket buffer and returns a pointer
1566 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1568 refcount_inc(&skb->users);
1573 * If users == 1, we are the only owner and can avoid redundant atomic changes.
1577 * skb_cloned - is the buffer a clone
1578 * @skb: buffer to check
1580 * Returns true if the buffer was generated with skb_clone() and is
1581 * one of multiple shared copies of the buffer. Cloned buffers are
1582 * shared data so must not be written to under normal circumstances.
1584 static inline int skb_cloned(const struct sk_buff *skb)
1586 return skb->cloned &&
1587 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1590 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1592 might_sleep_if(gfpflags_allow_blocking(pri));
1594 if (skb_cloned(skb))
1595 return pskb_expand_head(skb, 0, 0, pri);
1601 * skb_header_cloned - is the header a clone
1602 * @skb: buffer to check
1604 * Returns true if modifying the header part of the buffer requires
1605 * the data to be copied.
1607 static inline int skb_header_cloned(const struct sk_buff *skb)
1614 dataref = atomic_read(&skb_shinfo(skb)->dataref);
1615 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1616 return dataref != 1;
1619 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
1621 might_sleep_if(gfpflags_allow_blocking(pri));
1623 if (skb_header_cloned(skb))
1624 return pskb_expand_head(skb, 0, 0, pri);
1630 * __skb_header_release - release reference to header
1631 * @skb: buffer to operate on
1633 static inline void __skb_header_release(struct sk_buff *skb)
1636 atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1641 * skb_shared - is the buffer shared
1642 * @skb: buffer to check
1644 * Returns true if more than one person has a reference to this
1647 static inline int skb_shared(const struct sk_buff *skb)
1649 return refcount_read(&skb->users) != 1;
1653 * skb_share_check - check if buffer is shared and if so clone it
1654 * @skb: buffer to check
1655 * @pri: priority for memory allocation
1657 * If the buffer is shared the buffer is cloned and the old copy
1658 * drops a reference. A new clone with a single reference is returned.
1659 * If the buffer is not shared the original buffer is returned. When
1660 * being called from interrupt status or with spinlocks held pri must
1663 * NULL is returned on a memory allocation failure.
1665 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1667 might_sleep_if(gfpflags_allow_blocking(pri));
1668 if (skb_shared(skb)) {
1669 struct sk_buff *nskb = skb_clone(skb, pri);
1681 * Copy shared buffers into a new sk_buff. We effectively do COW on
1682 * packets to handle cases where we have a local reader and forward
1683 * and a couple of other messy ones. The normal one is tcpdumping
1684 * a packet thats being forwarded.
1688 * skb_unshare - make a copy of a shared buffer
1689 * @skb: buffer to check
1690 * @pri: priority for memory allocation
1692 * If the socket buffer is a clone then this function creates a new
1693 * copy of the data, drops a reference count on the old copy and returns
1694 * the new copy with the reference count at 1. If the buffer is not a clone
1695 * the original buffer is returned. When called with a spinlock held or
1696 * from interrupt state @pri must be %GFP_ATOMIC
1698 * %NULL is returned on a memory allocation failure.
1700 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1703 might_sleep_if(gfpflags_allow_blocking(pri));
1704 if (skb_cloned(skb)) {
1705 struct sk_buff *nskb = skb_copy(skb, pri);
1707 /* Free our shared copy */
1718 * skb_peek - peek at the head of an &sk_buff_head
1719 * @list_: list to peek at
1721 * Peek an &sk_buff. Unlike most other operations you _MUST_
1722 * be careful with this one. A peek leaves the buffer on the
1723 * list and someone else may run off with it. You must hold
1724 * the appropriate locks or have a private queue to do this.
1726 * Returns %NULL for an empty list or a pointer to the head element.
1727 * The reference count is not incremented and the reference is therefore
1728 * volatile. Use with caution.
1730 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1732 struct sk_buff *skb = list_->next;
1734 if (skb == (struct sk_buff *)list_)
1740 * __skb_peek - peek at the head of a non-empty &sk_buff_head
1741 * @list_: list to peek at
1743 * Like skb_peek(), but the caller knows that the list is not empty.
1745 static inline struct sk_buff *__skb_peek(const struct sk_buff_head *list_)
1751 * skb_peek_next - peek skb following the given one from a queue
1752 * @skb: skb to start from
1753 * @list_: list to peek at
1755 * Returns %NULL when the end of the list is met or a pointer to the
1756 * next element. The reference count is not incremented and the
1757 * reference is therefore volatile. Use with caution.
1759 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1760 const struct sk_buff_head *list_)
1762 struct sk_buff *next = skb->next;
1764 if (next == (struct sk_buff *)list_)
1770 * skb_peek_tail - peek at the tail of an &sk_buff_head
1771 * @list_: list to peek at
1773 * Peek an &sk_buff. Unlike most other operations you _MUST_
1774 * be careful with this one. A peek leaves the buffer on the
1775 * list and someone else may run off with it. You must hold
1776 * the appropriate locks or have a private queue to do this.
1778 * Returns %NULL for an empty list or a pointer to the tail element.
1779 * The reference count is not incremented and the reference is therefore
1780 * volatile. Use with caution.
1782 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1784 struct sk_buff *skb = list_->prev;
1786 if (skb == (struct sk_buff *)list_)
1793 * skb_queue_len - get queue length
1794 * @list_: list to measure
1796 * Return the length of an &sk_buff queue.
1798 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1804 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1805 * @list: queue to initialize
1807 * This initializes only the list and queue length aspects of
1808 * an sk_buff_head object. This allows to initialize the list
1809 * aspects of an sk_buff_head without reinitializing things like
1810 * the spinlock. It can also be used for on-stack sk_buff_head
1811 * objects where the spinlock is known to not be used.
1813 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1815 list->prev = list->next = (struct sk_buff *)list;
1820 * This function creates a split out lock class for each invocation;
1821 * this is needed for now since a whole lot of users of the skb-queue
1822 * infrastructure in drivers have different locking usage (in hardirq)
1823 * than the networking core (in softirq only). In the long run either the
1824 * network layer or drivers should need annotation to consolidate the
1825 * main types of usage into 3 classes.
1827 static inline void skb_queue_head_init(struct sk_buff_head *list)
1829 spin_lock_init(&list->lock);
1830 __skb_queue_head_init(list);
1833 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1834 struct lock_class_key *class)
1836 skb_queue_head_init(list);
1837 lockdep_set_class(&list->lock, class);
1841 * Insert an sk_buff on a list.
1843 * The "__skb_xxxx()" functions are the non-atomic ones that
1844 * can only be called with interrupts disabled.
1846 static inline void __skb_insert(struct sk_buff *newsk,
1847 struct sk_buff *prev, struct sk_buff *next,
1848 struct sk_buff_head *list)
1852 next->prev = prev->next = newsk;
1856 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1857 struct sk_buff *prev,
1858 struct sk_buff *next)
1860 struct sk_buff *first = list->next;
1861 struct sk_buff *last = list->prev;
1871 * skb_queue_splice - join two skb lists, this is designed for stacks
1872 * @list: the new list to add
1873 * @head: the place to add it in the first list
1875 static inline void skb_queue_splice(const 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;
1885 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1886 * @list: the new list to add
1887 * @head: the place to add it in the first list
1889 * The list at @list is reinitialised
1891 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1892 struct sk_buff_head *head)
1894 if (!skb_queue_empty(list)) {
1895 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1896 head->qlen += list->qlen;
1897 __skb_queue_head_init(list);
1902 * skb_queue_splice_tail - join two skb lists, each list being a queue
1903 * @list: the new list to add
1904 * @head: the place to add it in the first list
1906 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1907 struct sk_buff_head *head)
1909 if (!skb_queue_empty(list)) {
1910 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1911 head->qlen += list->qlen;
1916 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1917 * @list: the new list to add
1918 * @head: the place to add it in the first list
1920 * Each of the lists is a queue.
1921 * The list at @list is reinitialised
1923 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1924 struct sk_buff_head *head)
1926 if (!skb_queue_empty(list)) {
1927 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1928 head->qlen += list->qlen;
1929 __skb_queue_head_init(list);
1934 * __skb_queue_after - queue a buffer at the list head
1935 * @list: list to use
1936 * @prev: place after this buffer
1937 * @newsk: buffer to queue
1939 * Queue a buffer int the middle of a list. This function takes no locks
1940 * and you must therefore hold required locks before calling it.
1942 * A buffer cannot be placed on two lists at the same time.
1944 static inline void __skb_queue_after(struct sk_buff_head *list,
1945 struct sk_buff *prev,
1946 struct sk_buff *newsk)
1948 __skb_insert(newsk, prev, prev->next, list);
1951 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1952 struct sk_buff_head *list);
1954 static inline void __skb_queue_before(struct sk_buff_head *list,
1955 struct sk_buff *next,
1956 struct sk_buff *newsk)
1958 __skb_insert(newsk, next->prev, next, list);
1962 * __skb_queue_head - queue a buffer at the list head
1963 * @list: list to use
1964 * @newsk: buffer to queue
1966 * Queue a buffer at the start of a list. This function takes no locks
1967 * and you must therefore hold required locks before calling it.
1969 * A buffer cannot be placed on two lists at the same time.
1971 static inline void __skb_queue_head(struct sk_buff_head *list,
1972 struct sk_buff *newsk)
1974 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1976 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1979 * __skb_queue_tail - queue a buffer at the list tail
1980 * @list: list to use
1981 * @newsk: buffer to queue
1983 * Queue a buffer at the end of a list. This function takes no locks
1984 * and you must therefore hold required locks before calling it.
1986 * A buffer cannot be placed on two lists at the same time.
1988 static inline void __skb_queue_tail(struct sk_buff_head *list,
1989 struct sk_buff *newsk)
1991 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1993 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1996 * remove sk_buff from list. _Must_ be called atomically, and with
1999 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
2000 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
2002 struct sk_buff *next, *prev;
2007 skb->next = skb->prev = NULL;
2013 * __skb_dequeue - remove from the head of the queue
2014 * @list: list to dequeue from
2016 * Remove the head of the list. This function does not take any locks
2017 * so must be used with appropriate locks held only. The head item is
2018 * returned or %NULL if the list is empty.
2020 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
2022 struct sk_buff *skb = skb_peek(list);
2024 __skb_unlink(skb, list);
2027 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
2030 * __skb_dequeue_tail - remove from the tail of the queue
2031 * @list: list to dequeue from
2033 * Remove the tail of the list. This function does not take any locks
2034 * so must be used with appropriate locks held only. The tail item is
2035 * returned or %NULL if the list is empty.
2037 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
2039 struct sk_buff *skb = skb_peek_tail(list);
2041 __skb_unlink(skb, list);
2044 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
2047 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
2049 return skb->data_len;
2052 static inline unsigned int skb_headlen(const struct sk_buff *skb)
2054 return skb->len - skb->data_len;
2057 static inline unsigned int __skb_pagelen(const struct sk_buff *skb)
2059 unsigned int i, len = 0;
2061 for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--)
2062 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
2066 static inline unsigned int skb_pagelen(const struct sk_buff *skb)
2068 return skb_headlen(skb) + __skb_pagelen(skb);
2072 * __skb_fill_page_desc - initialise a paged fragment in an skb
2073 * @skb: buffer containing fragment to be initialised
2074 * @i: paged fragment index to initialise
2075 * @page: the page to use for this fragment
2076 * @off: the offset to the data with @page
2077 * @size: the length of the data
2079 * Initialises the @i'th fragment of @skb to point to &size bytes at
2080 * offset @off within @page.
2082 * Does not take any additional reference on the fragment.
2084 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
2085 struct page *page, int off, int size)
2087 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2090 * Propagate page pfmemalloc to the skb if we can. The problem is
2091 * that not all callers have unique ownership of the page but rely
2092 * on page_is_pfmemalloc doing the right thing(tm).
2094 frag->bv_page = page;
2095 frag->bv_offset = off;
2096 skb_frag_size_set(frag, size);
2098 page = compound_head(page);
2099 if (page_is_pfmemalloc(page))
2100 skb->pfmemalloc = true;
2104 * skb_fill_page_desc - initialise a paged fragment in an skb
2105 * @skb: buffer containing fragment to be initialised
2106 * @i: paged fragment index to initialise
2107 * @page: the page to use for this fragment
2108 * @off: the offset to the data with @page
2109 * @size: the length of the data
2111 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
2112 * @skb to point to @size bytes at offset @off within @page. In
2113 * addition updates @skb such that @i is the last fragment.
2115 * Does not take any additional reference on the fragment.
2117 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
2118 struct page *page, int off, int size)
2120 __skb_fill_page_desc(skb, i, page, off, size);
2121 skb_shinfo(skb)->nr_frags = i + 1;
2124 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
2125 int size, unsigned int truesize);
2127 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
2128 unsigned int truesize);
2130 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
2132 #ifdef NET_SKBUFF_DATA_USES_OFFSET
2133 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2135 return skb->head + skb->tail;
2138 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2140 skb->tail = skb->data - skb->head;
2143 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2145 skb_reset_tail_pointer(skb);
2146 skb->tail += offset;
2149 #else /* NET_SKBUFF_DATA_USES_OFFSET */
2150 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2155 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2157 skb->tail = skb->data;
2160 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2162 skb->tail = skb->data + offset;
2165 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
2168 * Add data to an sk_buff
2170 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
2171 void *skb_put(struct sk_buff *skb, unsigned int len);
2172 static inline void *__skb_put(struct sk_buff *skb, unsigned int len)
2174 void *tmp = skb_tail_pointer(skb);
2175 SKB_LINEAR_ASSERT(skb);
2181 static inline void *__skb_put_zero(struct sk_buff *skb, unsigned int len)
2183 void *tmp = __skb_put(skb, len);
2185 memset(tmp, 0, len);
2189 static inline void *__skb_put_data(struct sk_buff *skb, const void *data,
2192 void *tmp = __skb_put(skb, len);
2194 memcpy(tmp, data, len);
2198 static inline void __skb_put_u8(struct sk_buff *skb, u8 val)
2200 *(u8 *)__skb_put(skb, 1) = val;
2203 static inline void *skb_put_zero(struct sk_buff *skb, unsigned int len)
2205 void *tmp = skb_put(skb, len);
2207 memset(tmp, 0, len);
2212 static inline void *skb_put_data(struct sk_buff *skb, const void *data,
2215 void *tmp = skb_put(skb, len);
2217 memcpy(tmp, data, len);
2222 static inline void skb_put_u8(struct sk_buff *skb, u8 val)
2224 *(u8 *)skb_put(skb, 1) = val;
2227 void *skb_push(struct sk_buff *skb, unsigned int len);
2228 static inline void *__skb_push(struct sk_buff *skb, unsigned int len)
2235 void *skb_pull(struct sk_buff *skb, unsigned int len);
2236 static inline void *__skb_pull(struct sk_buff *skb, unsigned int len)
2239 BUG_ON(skb->len < skb->data_len);
2240 return skb->data += len;
2243 static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len)
2245 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
2248 void *__pskb_pull_tail(struct sk_buff *skb, int delta);
2250 static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len)
2252 if (len > skb_headlen(skb) &&
2253 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
2256 return skb->data += len;
2259 static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
2261 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
2264 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
2266 if (likely(len <= skb_headlen(skb)))
2268 if (unlikely(len > skb->len))
2270 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
2273 void skb_condense(struct sk_buff *skb);
2276 * skb_headroom - bytes at buffer head
2277 * @skb: buffer to check
2279 * Return the number of bytes of free space at the head of an &sk_buff.
2281 static inline unsigned int skb_headroom(const struct sk_buff *skb)
2283 return skb->data - skb->head;
2287 * skb_tailroom - bytes at buffer end
2288 * @skb: buffer to check
2290 * Return the number of bytes of free space at the tail of an sk_buff
2292 static inline int skb_tailroom(const struct sk_buff *skb)
2294 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
2298 * skb_availroom - bytes at buffer end
2299 * @skb: buffer to check
2301 * Return the number of bytes of free space at the tail of an sk_buff
2302 * allocated by sk_stream_alloc()
2304 static inline int skb_availroom(const struct sk_buff *skb)
2306 if (skb_is_nonlinear(skb))
2309 return skb->end - skb->tail - skb->reserved_tailroom;
2313 * skb_reserve - adjust headroom
2314 * @skb: buffer to alter
2315 * @len: bytes to move
2317 * Increase the headroom of an empty &sk_buff by reducing the tail
2318 * room. This is only allowed for an empty buffer.
2320 static inline void skb_reserve(struct sk_buff *skb, int len)
2327 * skb_tailroom_reserve - adjust reserved_tailroom
2328 * @skb: buffer to alter
2329 * @mtu: maximum amount of headlen permitted
2330 * @needed_tailroom: minimum amount of reserved_tailroom
2332 * Set reserved_tailroom so that headlen can be as large as possible but
2333 * not larger than mtu and tailroom cannot be smaller than
2335 * The required headroom should already have been reserved before using
2338 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2339 unsigned int needed_tailroom)
2341 SKB_LINEAR_ASSERT(skb);
2342 if (mtu < skb_tailroom(skb) - needed_tailroom)
2343 /* use at most mtu */
2344 skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2346 /* use up to all available space */
2347 skb->reserved_tailroom = needed_tailroom;
2350 #define ENCAP_TYPE_ETHER 0
2351 #define ENCAP_TYPE_IPPROTO 1
2353 static inline void skb_set_inner_protocol(struct sk_buff *skb,
2356 skb->inner_protocol = protocol;
2357 skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2360 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2363 skb->inner_ipproto = ipproto;
2364 skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2367 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2369 skb->inner_mac_header = skb->mac_header;
2370 skb->inner_network_header = skb->network_header;
2371 skb->inner_transport_header = skb->transport_header;
2374 static inline void skb_reset_mac_len(struct sk_buff *skb)
2376 skb->mac_len = skb->network_header - skb->mac_header;
2379 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2382 return skb->head + skb->inner_transport_header;
2385 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2387 return skb_inner_transport_header(skb) - skb->data;
2390 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2392 skb->inner_transport_header = skb->data - skb->head;
2395 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2398 skb_reset_inner_transport_header(skb);
2399 skb->inner_transport_header += offset;
2402 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2404 return skb->head + skb->inner_network_header;
2407 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2409 skb->inner_network_header = skb->data - skb->head;
2412 static inline void skb_set_inner_network_header(struct sk_buff *skb,
2415 skb_reset_inner_network_header(skb);
2416 skb->inner_network_header += offset;
2419 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2421 return skb->head + skb->inner_mac_header;
2424 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2426 skb->inner_mac_header = skb->data - skb->head;
2429 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2432 skb_reset_inner_mac_header(skb);
2433 skb->inner_mac_header += offset;
2435 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2437 return skb->transport_header != (typeof(skb->transport_header))~0U;
2440 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2442 return skb->head + skb->transport_header;
2445 static inline void skb_reset_transport_header(struct sk_buff *skb)
2447 skb->transport_header = skb->data - skb->head;
2450 static inline void skb_set_transport_header(struct sk_buff *skb,
2453 skb_reset_transport_header(skb);
2454 skb->transport_header += offset;
2457 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2459 return skb->head + skb->network_header;
2462 static inline void skb_reset_network_header(struct sk_buff *skb)
2464 skb->network_header = skb->data - skb->head;
2467 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2469 skb_reset_network_header(skb);
2470 skb->network_header += offset;
2473 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2475 return skb->head + skb->mac_header;
2478 static inline int skb_mac_offset(const struct sk_buff *skb)
2480 return skb_mac_header(skb) - skb->data;
2483 static inline u32 skb_mac_header_len(const struct sk_buff *skb)
2485 return skb->network_header - skb->mac_header;
2488 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2490 return skb->mac_header != (typeof(skb->mac_header))~0U;
2493 static inline void skb_reset_mac_header(struct sk_buff *skb)
2495 skb->mac_header = skb->data - skb->head;
2498 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2500 skb_reset_mac_header(skb);
2501 skb->mac_header += offset;
2504 static inline void skb_pop_mac_header(struct sk_buff *skb)
2506 skb->mac_header = skb->network_header;
2509 static inline void skb_probe_transport_header(struct sk_buff *skb)
2511 struct flow_keys_basic keys;
2513 if (skb_transport_header_was_set(skb))
2516 if (skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
2518 skb_set_transport_header(skb, keys.control.thoff);
2521 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2523 if (skb_mac_header_was_set(skb)) {
2524 const unsigned char *old_mac = skb_mac_header(skb);
2526 skb_set_mac_header(skb, -skb->mac_len);
2527 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2531 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2533 return skb->csum_start - skb_headroom(skb);
2536 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
2538 return skb->head + skb->csum_start;
2541 static inline int skb_transport_offset(const struct sk_buff *skb)
2543 return skb_transport_header(skb) - skb->data;
2546 static inline u32 skb_network_header_len(const struct sk_buff *skb)
2548 return skb->transport_header - skb->network_header;
2551 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2553 return skb->inner_transport_header - skb->inner_network_header;
2556 static inline int skb_network_offset(const struct sk_buff *skb)
2558 return skb_network_header(skb) - skb->data;
2561 static inline int skb_inner_network_offset(const struct sk_buff *skb)
2563 return skb_inner_network_header(skb) - skb->data;
2566 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2568 return pskb_may_pull(skb, skb_network_offset(skb) + len);
2572 * CPUs often take a performance hit when accessing unaligned memory
2573 * locations. The actual performance hit varies, it can be small if the
2574 * hardware handles it or large if we have to take an exception and fix it
2577 * Since an ethernet header is 14 bytes network drivers often end up with
2578 * the IP header at an unaligned offset. The IP header can be aligned by
2579 * shifting the start of the packet by 2 bytes. Drivers should do this
2582 * skb_reserve(skb, NET_IP_ALIGN);
2584 * The downside to this alignment of the IP header is that the DMA is now
2585 * unaligned. On some architectures the cost of an unaligned DMA is high
2586 * and this cost outweighs the gains made by aligning the IP header.
2588 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2591 #ifndef NET_IP_ALIGN
2592 #define NET_IP_ALIGN 2
2596 * The networking layer reserves some headroom in skb data (via
2597 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2598 * the header has to grow. In the default case, if the header has to grow
2599 * 32 bytes or less we avoid the reallocation.
2601 * Unfortunately this headroom changes the DMA alignment of the resulting
2602 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2603 * on some architectures. An architecture can override this value,
2604 * perhaps setting it to a cacheline in size (since that will maintain
2605 * cacheline alignment of the DMA). It must be a power of 2.
2607 * Various parts of the networking layer expect at least 32 bytes of
2608 * headroom, you should not reduce this.
2610 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2611 * to reduce average number of cache lines per packet.
2612 * get_rps_cpus() for example only access one 64 bytes aligned block :
2613 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2616 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
2619 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2621 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
2623 if (WARN_ON(skb_is_nonlinear(skb)))
2626 skb_set_tail_pointer(skb, len);
2629 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2631 __skb_set_length(skb, len);
2634 void skb_trim(struct sk_buff *skb, unsigned int len);
2636 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2639 return ___pskb_trim(skb, len);
2640 __skb_trim(skb, len);
2644 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2646 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2650 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2651 * @skb: buffer to alter
2654 * This is identical to pskb_trim except that the caller knows that
2655 * the skb is not cloned so we should never get an error due to out-
2658 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2660 int err = pskb_trim(skb, len);
2664 static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
2666 unsigned int diff = len - skb->len;
2668 if (skb_tailroom(skb) < diff) {
2669 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
2674 __skb_set_length(skb, len);
2679 * skb_orphan - orphan a buffer
2680 * @skb: buffer to orphan
2682 * If a buffer currently has an owner then we call the owner's
2683 * destructor function and make the @skb unowned. The buffer continues
2684 * to exist but is no longer charged to its former owner.
2686 static inline void skb_orphan(struct sk_buff *skb)
2688 if (skb->destructor) {
2689 skb->destructor(skb);
2690 skb->destructor = NULL;
2698 * skb_orphan_frags - orphan the frags contained in a buffer
2699 * @skb: buffer to orphan frags from
2700 * @gfp_mask: allocation mask for replacement pages
2702 * For each frag in the SKB which needs a destructor (i.e. has an
2703 * owner) create a copy of that frag and release the original
2704 * page by calling the destructor.
2706 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2708 if (likely(!skb_zcopy(skb)))
2710 if (!skb_zcopy_is_nouarg(skb) &&
2711 skb_uarg(skb)->callback == sock_zerocopy_callback)
2713 return skb_copy_ubufs(skb, gfp_mask);
2716 /* Frags must be orphaned, even if refcounted, if skb might loop to rx path */
2717 static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask)
2719 if (likely(!skb_zcopy(skb)))
2721 return skb_copy_ubufs(skb, gfp_mask);
2725 * __skb_queue_purge - empty a list
2726 * @list: list to empty
2728 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2729 * the list and one reference dropped. This function does not take the
2730 * list lock and the caller must hold the relevant locks to use it.
2732 static inline void __skb_queue_purge(struct sk_buff_head *list)
2734 struct sk_buff *skb;
2735 while ((skb = __skb_dequeue(list)) != NULL)
2738 void skb_queue_purge(struct sk_buff_head *list);
2740 unsigned int skb_rbtree_purge(struct rb_root *root);
2742 void *netdev_alloc_frag(unsigned int fragsz);
2744 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2748 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
2749 * @dev: network device to receive on
2750 * @length: length to allocate
2752 * Allocate a new &sk_buff and assign it a usage count of one. The
2753 * buffer has unspecified headroom built in. Users should allocate
2754 * the headroom they think they need without accounting for the
2755 * built in space. The built in space is used for optimisations.
2757 * %NULL is returned if there is no free memory. Although this function
2758 * allocates memory it can be called from an interrupt.
2760 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2761 unsigned int length)
2763 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2766 /* legacy helper around __netdev_alloc_skb() */
2767 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2770 return __netdev_alloc_skb(NULL, length, gfp_mask);
2773 /* legacy helper around netdev_alloc_skb() */
2774 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2776 return netdev_alloc_skb(NULL, length);
2780 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2781 unsigned int length, gfp_t gfp)
2783 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2785 if (NET_IP_ALIGN && skb)
2786 skb_reserve(skb, NET_IP_ALIGN);
2790 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2791 unsigned int length)
2793 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2796 static inline void skb_free_frag(void *addr)
2798 page_frag_free(addr);
2801 void *napi_alloc_frag(unsigned int fragsz);
2802 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2803 unsigned int length, gfp_t gfp_mask);
2804 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2805 unsigned int length)
2807 return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2809 void napi_consume_skb(struct sk_buff *skb, int budget);
2811 void __kfree_skb_flush(void);
2812 void __kfree_skb_defer(struct sk_buff *skb);
2815 * __dev_alloc_pages - allocate page for network Rx
2816 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2817 * @order: size of the allocation
2819 * Allocate a new page.
2821 * %NULL is returned if there is no free memory.
2823 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2826 /* This piece of code contains several assumptions.
2827 * 1. This is for device Rx, therefor a cold page is preferred.
2828 * 2. The expectation is the user wants a compound page.
2829 * 3. If requesting a order 0 page it will not be compound
2830 * due to the check to see if order has a value in prep_new_page
2831 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2832 * code in gfp_to_alloc_flags that should be enforcing this.
2834 gfp_mask |= __GFP_COMP | __GFP_MEMALLOC;
2836 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2839 static inline struct page *dev_alloc_pages(unsigned int order)
2841 return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
2845 * __dev_alloc_page - allocate a page for network Rx
2846 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2848 * Allocate a new page.
2850 * %NULL is returned if there is no free memory.
2852 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2854 return __dev_alloc_pages(gfp_mask, 0);
2857 static inline struct page *dev_alloc_page(void)
2859 return dev_alloc_pages(0);
2863 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2864 * @page: The page that was allocated from skb_alloc_page
2865 * @skb: The skb that may need pfmemalloc set
2867 static inline void skb_propagate_pfmemalloc(struct page *page,
2868 struct sk_buff *skb)
2870 if (page_is_pfmemalloc(page))
2871 skb->pfmemalloc = true;
2875 * skb_frag_off() - Returns the offset of a skb fragment
2876 * @frag: the paged fragment
2878 static inline unsigned int skb_frag_off(const skb_frag_t *frag)
2880 return frag->bv_offset;
2884 * skb_frag_off_add() - Increments the offset of a skb fragment by @delta
2885 * @frag: skb fragment
2886 * @delta: value to add
2888 static inline void skb_frag_off_add(skb_frag_t *frag, int delta)
2890 frag->bv_offset += delta;
2894 * skb_frag_off_set() - Sets the offset of a skb fragment
2895 * @frag: skb fragment
2896 * @offset: offset of fragment
2898 static inline void skb_frag_off_set(skb_frag_t *frag, unsigned int offset)
2900 frag->bv_offset = offset;
2904 * skb_frag_off_copy() - Sets the offset of a skb fragment from another fragment
2905 * @fragto: skb fragment where offset is set
2906 * @fragfrom: skb fragment offset is copied from
2908 static inline void skb_frag_off_copy(skb_frag_t *fragto,
2909 const skb_frag_t *fragfrom)
2911 fragto->bv_offset = fragfrom->bv_offset;
2915 * skb_frag_page - retrieve the page referred to by a paged fragment
2916 * @frag: the paged fragment
2918 * Returns the &struct page associated with @frag.
2920 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2922 return frag->bv_page;
2926 * __skb_frag_ref - take an addition reference on a paged fragment.
2927 * @frag: the paged fragment
2929 * Takes an additional reference on the paged fragment @frag.
2931 static inline void __skb_frag_ref(skb_frag_t *frag)
2933 get_page(skb_frag_page(frag));
2937 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2939 * @f: the fragment offset.
2941 * Takes an additional reference on the @f'th paged fragment of @skb.
2943 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2945 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2949 * __skb_frag_unref - release a reference on a paged fragment.
2950 * @frag: the paged fragment
2952 * Releases a reference on the paged fragment @frag.
2954 static inline void __skb_frag_unref(skb_frag_t *frag)
2956 put_page(skb_frag_page(frag));
2960 * skb_frag_unref - release a reference on a paged fragment of an skb.
2962 * @f: the fragment offset
2964 * Releases a reference on the @f'th paged fragment of @skb.
2966 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2968 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2972 * skb_frag_address - gets the address of the data contained in a paged fragment
2973 * @frag: the paged fragment buffer
2975 * Returns the address of the data within @frag. The page must already
2978 static inline void *skb_frag_address(const skb_frag_t *frag)
2980 return page_address(skb_frag_page(frag)) + skb_frag_off(frag);
2984 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2985 * @frag: the paged fragment buffer
2987 * Returns the address of the data within @frag. Checks that the page
2988 * is mapped and returns %NULL otherwise.
2990 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2992 void *ptr = page_address(skb_frag_page(frag));
2996 return ptr + skb_frag_off(frag);
3000 * skb_frag_page_copy() - sets the page in a fragment from another fragment
3001 * @fragto: skb fragment where page is set
3002 * @fragfrom: skb fragment page is copied from
3004 static inline void skb_frag_page_copy(skb_frag_t *fragto,
3005 const skb_frag_t *fragfrom)
3007 fragto->bv_page = fragfrom->bv_page;
3011 * __skb_frag_set_page - sets the page contained in a paged fragment
3012 * @frag: the paged fragment
3013 * @page: the page to set
3015 * Sets the fragment @frag to contain @page.
3017 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
3019 frag->bv_page = page;
3023 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
3025 * @f: the fragment offset
3026 * @page: the page to set
3028 * Sets the @f'th fragment of @skb to contain @page.
3030 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
3033 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
3036 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
3039 * skb_frag_dma_map - maps a paged fragment via the DMA API
3040 * @dev: the device to map the fragment to
3041 * @frag: the paged fragment to map
3042 * @offset: the offset within the fragment (starting at the
3043 * fragment's own offset)
3044 * @size: the number of bytes to map
3045 * @dir: the direction of the mapping (``PCI_DMA_*``)
3047 * Maps the page associated with @frag to @device.
3049 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
3050 const skb_frag_t *frag,
3051 size_t offset, size_t size,
3052 enum dma_data_direction dir)
3054 return dma_map_page(dev, skb_frag_page(frag),
3055 skb_frag_off(frag) + offset, size, dir);
3058 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
3061 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
3065 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
3068 return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
3073 * skb_clone_writable - is the header of a clone writable
3074 * @skb: buffer to check
3075 * @len: length up to which to write
3077 * Returns true if modifying the header part of the cloned buffer
3078 * does not requires the data to be copied.
3080 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
3082 return !skb_header_cloned(skb) &&
3083 skb_headroom(skb) + len <= skb->hdr_len;
3086 static inline int skb_try_make_writable(struct sk_buff *skb,
3087 unsigned int write_len)
3089 return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
3090 pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
3093 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
3098 if (headroom > skb_headroom(skb))
3099 delta = headroom - skb_headroom(skb);
3101 if (delta || cloned)
3102 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
3108 * skb_cow - copy header of skb when it is required
3109 * @skb: buffer to cow
3110 * @headroom: needed headroom
3112 * If the skb passed lacks sufficient headroom or its data part
3113 * is shared, data is reallocated. If reallocation fails, an error
3114 * is returned and original skb is not changed.
3116 * The result is skb with writable area skb->head...skb->tail
3117 * and at least @headroom of space at head.
3119 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
3121 return __skb_cow(skb, headroom, skb_cloned(skb));
3125 * skb_cow_head - skb_cow but only making the head writable
3126 * @skb: buffer to cow
3127 * @headroom: needed headroom
3129 * This function is identical to skb_cow except that we replace the
3130 * skb_cloned check by skb_header_cloned. It should be used when
3131 * you only need to push on some header and do not need to modify
3134 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
3136 return __skb_cow(skb, headroom, skb_header_cloned(skb));
3140 * skb_padto - pad an skbuff up to a minimal size
3141 * @skb: buffer to pad
3142 * @len: minimal length
3144 * Pads up a buffer to ensure the trailing bytes exist and are
3145 * blanked. If the buffer already contains sufficient data it
3146 * is untouched. Otherwise it is extended. Returns zero on
3147 * success. The skb is freed on error.
3149 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
3151 unsigned int size = skb->len;
3152 if (likely(size >= len))
3154 return skb_pad(skb, len - size);
3158 * __skb_put_padto - increase size and pad an skbuff up to a minimal size
3159 * @skb: buffer to pad
3160 * @len: minimal length
3161 * @free_on_error: free buffer on error
3163 * Pads up a buffer to ensure the trailing bytes exist and are
3164 * blanked. If the buffer already contains sufficient data it
3165 * is untouched. Otherwise it is extended. Returns zero on
3166 * success. The skb is freed on error if @free_on_error is true.
3168 static inline int __skb_put_padto(struct sk_buff *skb, unsigned int len,
3171 unsigned int size = skb->len;
3173 if (unlikely(size < len)) {
3175 if (__skb_pad(skb, len, free_on_error))
3177 __skb_put(skb, len);
3183 * skb_put_padto - increase size and pad an skbuff up to a minimal size
3184 * @skb: buffer to pad
3185 * @len: minimal length
3187 * Pads up a buffer to ensure the trailing bytes exist and are
3188 * blanked. If the buffer already contains sufficient data it
3189 * is untouched. Otherwise it is extended. Returns zero on
3190 * success. The skb is freed on error.
3192 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
3194 return __skb_put_padto(skb, len, true);
3197 static inline int skb_add_data(struct sk_buff *skb,
3198 struct iov_iter *from, int copy)
3200 const int off = skb->len;
3202 if (skb->ip_summed == CHECKSUM_NONE) {
3204 if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy,
3206 skb->csum = csum_block_add(skb->csum, csum, off);
3209 } else if (copy_from_iter_full(skb_put(skb, copy), copy, from))
3212 __skb_trim(skb, off);
3216 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
3217 const struct page *page, int off)
3222 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];
3224 return page == skb_frag_page(frag) &&
3225 off == skb_frag_off(frag) + skb_frag_size(frag);
3230 static inline int __skb_linearize(struct sk_buff *skb)
3232 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
3236 * skb_linearize - convert paged skb to linear one
3237 * @skb: buffer to linarize
3239 * If there is no free memory -ENOMEM is returned, otherwise zero
3240 * is returned and the old skb data released.
3242 static inline int skb_linearize(struct sk_buff *skb)
3244 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
3248 * skb_has_shared_frag - can any frag be overwritten
3249 * @skb: buffer to test
3251 * Return true if the skb has at least one frag that might be modified
3252 * by an external entity (as in vmsplice()/sendfile())
3254 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
3256 return skb_is_nonlinear(skb) &&
3257 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
3261 * skb_linearize_cow - make sure skb is linear and writable
3262 * @skb: buffer to process
3264 * If there is no free memory -ENOMEM is returned, otherwise zero
3265 * is returned and the old skb data released.
3267 static inline int skb_linearize_cow(struct sk_buff *skb)
3269 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
3270 __skb_linearize(skb) : 0;
3273 static __always_inline void
3274 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
3277 if (skb->ip_summed == CHECKSUM_COMPLETE)
3278 skb->csum = csum_block_sub(skb->csum,
3279 csum_partial(start, len, 0), off);
3280 else if (skb->ip_summed == CHECKSUM_PARTIAL &&
3281 skb_checksum_start_offset(skb) < 0)
3282 skb->ip_summed = CHECKSUM_NONE;
3286 * skb_postpull_rcsum - update checksum for received skb after pull
3287 * @skb: buffer to update
3288 * @start: start of data before pull
3289 * @len: length of data pulled
3291 * After doing a pull on a received packet, you need to call this to
3292 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
3293 * CHECKSUM_NONE so that it can be recomputed from scratch.
3295 static inline void skb_postpull_rcsum(struct sk_buff *skb,
3296 const void *start, unsigned int len)
3298 __skb_postpull_rcsum(skb, start, len, 0);
3301 static __always_inline void
3302 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
3305 if (skb->ip_summed == CHECKSUM_COMPLETE)
3306 skb->csum = csum_block_add(skb->csum,
3307 csum_partial(start, len, 0), off);
3311 * skb_postpush_rcsum - update checksum for received skb after push
3312 * @skb: buffer to update
3313 * @start: start of data after push
3314 * @len: length of data pushed
3316 * After doing a push on a received packet, you need to call this to
3317 * update the CHECKSUM_COMPLETE checksum.
3319 static inline void skb_postpush_rcsum(struct sk_buff *skb,
3320 const void *start, unsigned int len)
3322 __skb_postpush_rcsum(skb, start, len, 0);
3325 void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
3328 * skb_push_rcsum - push skb and update receive checksum
3329 * @skb: buffer to update
3330 * @len: length of data pulled
3332 * This function performs an skb_push on the packet and updates
3333 * the CHECKSUM_COMPLETE checksum. It should be used on
3334 * receive path processing instead of skb_push unless you know
3335 * that the checksum difference is zero (e.g., a valid IP header)
3336 * or you are setting ip_summed to CHECKSUM_NONE.
3338 static inline void *skb_push_rcsum(struct sk_buff *skb, unsigned int len)
3341 skb_postpush_rcsum(skb, skb->data, len);
3345 int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len);
3347 * pskb_trim_rcsum - trim received skb and update checksum
3348 * @skb: buffer to trim
3351 * This is exactly the same as pskb_trim except that it ensures the
3352 * checksum of received packets are still valid after the operation.
3353 * It can change skb pointers.
3356 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
3358 if (likely(len >= skb->len))
3360 return pskb_trim_rcsum_slow(skb, len);
3363 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
3365 if (skb->ip_summed == CHECKSUM_COMPLETE)
3366 skb->ip_summed = CHECKSUM_NONE;
3367 __skb_trim(skb, len);
3371 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
3373 if (skb->ip_summed == CHECKSUM_COMPLETE)
3374 skb->ip_summed = CHECKSUM_NONE;
3375 return __skb_grow(skb, len);
3378 #define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode)
3379 #define skb_rb_first(root) rb_to_skb(rb_first(root))
3380 #define skb_rb_last(root) rb_to_skb(rb_last(root))
3381 #define skb_rb_next(skb) rb_to_skb(rb_next(&(skb)->rbnode))
3382 #define skb_rb_prev(skb) rb_to_skb(rb_prev(&(skb)->rbnode))
3384 #define skb_queue_walk(queue, skb) \
3385 for (skb = (queue)->next; \
3386 skb != (struct sk_buff *)(queue); \
3389 #define skb_queue_walk_safe(queue, skb, tmp) \
3390 for (skb = (queue)->next, tmp = skb->next; \
3391 skb != (struct sk_buff *)(queue); \
3392 skb = tmp, tmp = skb->next)
3394 #define skb_queue_walk_from(queue, skb) \
3395 for (; skb != (struct sk_buff *)(queue); \
3398 #define skb_rbtree_walk(skb, root) \
3399 for (skb = skb_rb_first(root); skb != NULL; \
3400 skb = skb_rb_next(skb))
3402 #define skb_rbtree_walk_from(skb) \
3403 for (; skb != NULL; \
3404 skb = skb_rb_next(skb))
3406 #define skb_rbtree_walk_from_safe(skb, tmp) \
3407 for (; tmp = skb ? skb_rb_next(skb) : NULL, (skb != NULL); \
3410 #define skb_queue_walk_from_safe(queue, skb, tmp) \
3411 for (tmp = skb->next; \
3412 skb != (struct sk_buff *)(queue); \
3413 skb = tmp, tmp = skb->next)
3415 #define skb_queue_reverse_walk(queue, skb) \
3416 for (skb = (queue)->prev; \
3417 skb != (struct sk_buff *)(queue); \
3420 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
3421 for (skb = (queue)->prev, tmp = skb->prev; \
3422 skb != (struct sk_buff *)(queue); \
3423 skb = tmp, tmp = skb->prev)
3425 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
3426 for (tmp = skb->prev; \
3427 skb != (struct sk_buff *)(queue); \
3428 skb = tmp, tmp = skb->prev)
3430 static inline bool skb_has_frag_list(const struct sk_buff *skb)
3432 return skb_shinfo(skb)->frag_list != NULL;
3435 static inline void skb_frag_list_init(struct sk_buff *skb)
3437 skb_shinfo(skb)->frag_list = NULL;
3440 #define skb_walk_frags(skb, iter) \
3441 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3444 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
3445 const struct sk_buff *skb);
3446 struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
3447 struct sk_buff_head *queue,
3449 void (*destructor)(struct sock *sk,
3450 struct sk_buff *skb),
3452 struct sk_buff **last);
3453 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
3454 void (*destructor)(struct sock *sk,
3455 struct sk_buff *skb),
3457 struct sk_buff **last);
3458 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
3459 void (*destructor)(struct sock *sk,
3460 struct sk_buff *skb),
3461 int *off, int *err);
3462 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
3464 __poll_t datagram_poll(struct file *file, struct socket *sock,
3465 struct poll_table_struct *wait);
3466 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
3467 struct iov_iter *to, int size);
3468 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
3469 struct msghdr *msg, int size)
3471 return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
3473 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
3474 struct msghdr *msg);
3475 int skb_copy_and_hash_datagram_iter(const struct sk_buff *skb, int offset,
3476 struct iov_iter *to, int len,
3477 struct ahash_request *hash);
3478 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
3479 struct iov_iter *from, int len);
3480 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
3481 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
3482 void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
3483 static inline void skb_free_datagram_locked(struct sock *sk,
3484 struct sk_buff *skb)
3486 __skb_free_datagram_locked(sk, skb, 0);
3488 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
3489 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
3490 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
3491 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
3492 int len, __wsum csum);
3493 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3494 struct pipe_inode_info *pipe, unsigned int len,
3495 unsigned int flags);
3496 int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
3498 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
3499 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
3500 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
3502 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
3503 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
3504 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
3505 bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu);
3506 bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len);
3507 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
3508 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
3509 int skb_ensure_writable(struct sk_buff *skb, int write_len);
3510 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
3511 int skb_vlan_pop(struct sk_buff *skb);
3512 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
3513 int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto);
3514 int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto);
3515 int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse);
3516 int skb_mpls_dec_ttl(struct sk_buff *skb);
3517 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
3520 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
3522 return copy_from_iter_full(data, len, &msg->msg_iter) ? 0 : -EFAULT;
3525 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
3527 return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3530 struct skb_checksum_ops {
3531 __wsum (*update)(const void *mem, int len, __wsum wsum);
3532 __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
3535 extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly;
3537 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3538 __wsum csum, const struct skb_checksum_ops *ops);
3539 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
3542 static inline void * __must_check
3543 __skb_header_pointer(const struct sk_buff *skb, int offset,
3544 int len, void *data, int hlen, void *buffer)
3546 if (hlen - offset >= len)
3547 return data + offset;
3550 skb_copy_bits(skb, offset, buffer, len) < 0)
3556 static inline void * __must_check
3557 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
3559 return __skb_header_pointer(skb, offset, len, skb->data,
3560 skb_headlen(skb), buffer);
3564 * skb_needs_linearize - check if we need to linearize a given skb
3565 * depending on the given device features.
3566 * @skb: socket buffer to check
3567 * @features: net device features
3569 * Returns true if either:
3570 * 1. skb has frag_list and the device doesn't support FRAGLIST, or
3571 * 2. skb is fragmented and the device does not support SG.
3573 static inline bool skb_needs_linearize(struct sk_buff *skb,
3574 netdev_features_t features)
3576 return skb_is_nonlinear(skb) &&
3577 ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3578 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3581 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3583 const unsigned int len)
3585 memcpy(to, skb->data, len);
3588 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3589 const int offset, void *to,
3590 const unsigned int len)
3592 memcpy(to, skb->data + offset, len);
3595 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3597 const unsigned int len)
3599 memcpy(skb->data, from, len);
3602 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3605 const unsigned int len)
3607 memcpy(skb->data + offset, from, len);
3610 void skb_init(void);
3612 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3618 * skb_get_timestamp - get timestamp from a skb
3619 * @skb: skb to get stamp from
3620 * @stamp: pointer to struct __kernel_old_timeval to store stamp in
3622 * Timestamps are stored in the skb as offsets to a base timestamp.
3623 * This function converts the offset back to a struct timeval and stores
3626 static inline void skb_get_timestamp(const struct sk_buff *skb,
3627 struct __kernel_old_timeval *stamp)
3629 *stamp = ns_to_kernel_old_timeval(skb->tstamp);
3632 static inline void skb_get_new_timestamp(const struct sk_buff *skb,
3633 struct __kernel_sock_timeval *stamp)
3635 struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
3637 stamp->tv_sec = ts.tv_sec;
3638 stamp->tv_usec = ts.tv_nsec / 1000;
3641 static inline void skb_get_timestampns(const struct sk_buff *skb,
3642 struct timespec *stamp)
3644 *stamp = ktime_to_timespec(skb->tstamp);
3647 static inline void skb_get_new_timestampns(const struct sk_buff *skb,
3648 struct __kernel_timespec *stamp)
3650 struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
3652 stamp->tv_sec = ts.tv_sec;
3653 stamp->tv_nsec = ts.tv_nsec;
3656 static inline void __net_timestamp(struct sk_buff *skb)
3658 skb->tstamp = ktime_get_real();
3661 static inline ktime_t net_timedelta(ktime_t t)
3663 return ktime_sub(ktime_get_real(), t);
3666 static inline ktime_t net_invalid_timestamp(void)
3671 static inline u8 skb_metadata_len(const struct sk_buff *skb)
3673 return skb_shinfo(skb)->meta_len;
3676 static inline void *skb_metadata_end(const struct sk_buff *skb)
3678 return skb_mac_header(skb);
3681 static inline bool __skb_metadata_differs(const struct sk_buff *skb_a,
3682 const struct sk_buff *skb_b,
3685 const void *a = skb_metadata_end(skb_a);
3686 const void *b = skb_metadata_end(skb_b);
3687 /* Using more efficient varaiant than plain call to memcmp(). */
3688 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
3692 #define __it(x, op) (x -= sizeof(u##op))
3693 #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op))
3694 case 32: diffs |= __it_diff(a, b, 64);
3696 case 24: diffs |= __it_diff(a, b, 64);
3698 case 16: diffs |= __it_diff(a, b, 64);
3700 case 8: diffs |= __it_diff(a, b, 64);
3702 case 28: diffs |= __it_diff(a, b, 64);
3704 case 20: diffs |= __it_diff(a, b, 64);
3706 case 12: diffs |= __it_diff(a, b, 64);
3708 case 4: diffs |= __it_diff(a, b, 32);
3713 return memcmp(a - meta_len, b - meta_len, meta_len);
3717 static inline bool skb_metadata_differs(const struct sk_buff *skb_a,
3718 const struct sk_buff *skb_b)
3720 u8 len_a = skb_metadata_len(skb_a);
3721 u8 len_b = skb_metadata_len(skb_b);
3723 if (!(len_a | len_b))
3726 return len_a != len_b ?
3727 true : __skb_metadata_differs(skb_a, skb_b, len_a);
3730 static inline void skb_metadata_set(struct sk_buff *skb, u8 meta_len)
3732 skb_shinfo(skb)->meta_len = meta_len;
3735 static inline void skb_metadata_clear(struct sk_buff *skb)
3737 skb_metadata_set(skb, 0);
3740 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3742 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3744 void skb_clone_tx_timestamp(struct sk_buff *skb);
3745 bool skb_defer_rx_timestamp(struct sk_buff *skb);
3747 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3749 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3753 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3758 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3761 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3763 * PHY drivers may accept clones of transmitted packets for
3764 * timestamping via their phy_driver.txtstamp method. These drivers
3765 * must call this function to return the skb back to the stack with a
3768 * @skb: clone of the the original outgoing packet
3769 * @hwtstamps: hardware time stamps
3772 void skb_complete_tx_timestamp(struct sk_buff *skb,
3773 struct skb_shared_hwtstamps *hwtstamps);
3775 void __skb_tstamp_tx(struct sk_buff *orig_skb,
3776 struct skb_shared_hwtstamps *hwtstamps,
3777 struct sock *sk, int tstype);
3780 * skb_tstamp_tx - queue clone of skb with send time stamps
3781 * @orig_skb: the original outgoing packet
3782 * @hwtstamps: hardware time stamps, may be NULL if not available
3784 * If the skb has a socket associated, then this function clones the
3785 * skb (thus sharing the actual data and optional structures), stores
3786 * the optional hardware time stamping information (if non NULL) or
3787 * generates a software time stamp (otherwise), then queues the clone
3788 * to the error queue of the socket. Errors are silently ignored.
3790 void skb_tstamp_tx(struct sk_buff *orig_skb,
3791 struct skb_shared_hwtstamps *hwtstamps);
3794 * skb_tx_timestamp() - Driver hook for transmit timestamping
3796 * Ethernet MAC Drivers should call this function in their hard_xmit()
3797 * function immediately before giving the sk_buff to the MAC hardware.
3799 * Specifically, one should make absolutely sure that this function is
3800 * called before TX completion of this packet can trigger. Otherwise
3801 * the packet could potentially already be freed.
3803 * @skb: A socket buffer.
3805 static inline void skb_tx_timestamp(struct sk_buff *skb)
3807 skb_clone_tx_timestamp(skb);
3808 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
3809 skb_tstamp_tx(skb, NULL);
3813 * skb_complete_wifi_ack - deliver skb with wifi status
3815 * @skb: the original outgoing packet
3816 * @acked: ack status
3819 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3821 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3822 __sum16 __skb_checksum_complete(struct sk_buff *skb);
3824 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3826 return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3828 (skb->ip_summed == CHECKSUM_PARTIAL &&
3829 skb_checksum_start_offset(skb) >= 0));
3833 * skb_checksum_complete - Calculate checksum of an entire packet
3834 * @skb: packet to process
3836 * This function calculates the checksum over the entire packet plus
3837 * the value of skb->csum. The latter can be used to supply the
3838 * checksum of a pseudo header as used by TCP/UDP. It returns the
3841 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
3842 * this function can be used to verify that checksum on received
3843 * packets. In that case the function should return zero if the
3844 * checksum is correct. In particular, this function will return zero
3845 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3846 * hardware has already verified the correctness of the checksum.
3848 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3850 return skb_csum_unnecessary(skb) ?
3851 0 : __skb_checksum_complete(skb);
3854 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3856 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3857 if (skb->csum_level == 0)
3858 skb->ip_summed = CHECKSUM_NONE;
3864 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3866 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3867 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3869 } else if (skb->ip_summed == CHECKSUM_NONE) {
3870 skb->ip_summed = CHECKSUM_UNNECESSARY;
3871 skb->csum_level = 0;
3875 /* Check if we need to perform checksum complete validation.
3877 * Returns true if checksum complete is needed, false otherwise
3878 * (either checksum is unnecessary or zero checksum is allowed).
3880 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3884 if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3885 skb->csum_valid = 1;
3886 __skb_decr_checksum_unnecessary(skb);
3893 /* For small packets <= CHECKSUM_BREAK perform checksum complete directly
3896 #define CHECKSUM_BREAK 76
3898 /* Unset checksum-complete
3900 * Unset checksum complete can be done when packet is being modified
3901 * (uncompressed for instance) and checksum-complete value is
3904 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3906 if (skb->ip_summed == CHECKSUM_COMPLETE)
3907 skb->ip_summed = CHECKSUM_NONE;
3910 /* Validate (init) checksum based on checksum complete.
3913 * 0: checksum is validated or try to in skb_checksum_complete. In the latter
3914 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3915 * checksum is stored in skb->csum for use in __skb_checksum_complete
3916 * non-zero: value of invalid checksum
3919 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3923 if (skb->ip_summed == CHECKSUM_COMPLETE) {
3924 if (!csum_fold(csum_add(psum, skb->csum))) {
3925 skb->csum_valid = 1;
3932 if (complete || skb->len <= CHECKSUM_BREAK) {
3935 csum = __skb_checksum_complete(skb);
3936 skb->csum_valid = !csum;
3943 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3948 /* Perform checksum validate (init). Note that this is a macro since we only
3949 * want to calculate the pseudo header which is an input function if necessary.
3950 * First we try to validate without any computation (checksum unnecessary) and
3951 * then calculate based on checksum complete calling the function to compute
3955 * 0: checksum is validated or try to in skb_checksum_complete
3956 * non-zero: value of invalid checksum
3958 #define __skb_checksum_validate(skb, proto, complete, \
3959 zero_okay, check, compute_pseudo) \
3961 __sum16 __ret = 0; \
3962 skb->csum_valid = 0; \
3963 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
3964 __ret = __skb_checksum_validate_complete(skb, \
3965 complete, compute_pseudo(skb, proto)); \
3969 #define skb_checksum_init(skb, proto, compute_pseudo) \
3970 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3972 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3973 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3975 #define skb_checksum_validate(skb, proto, compute_pseudo) \
3976 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3978 #define skb_checksum_validate_zero_check(skb, proto, check, \
3980 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3982 #define skb_checksum_simple_validate(skb) \
3983 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3985 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3987 return (skb->ip_summed == CHECKSUM_NONE && skb->csum_valid);
3990 static inline void __skb_checksum_convert(struct sk_buff *skb, __wsum pseudo)
3992 skb->csum = ~pseudo;
3993 skb->ip_summed = CHECKSUM_COMPLETE;
3996 #define skb_checksum_try_convert(skb, proto, compute_pseudo) \
3998 if (__skb_checksum_convert_check(skb)) \
3999 __skb_checksum_convert(skb, compute_pseudo(skb, proto)); \
4002 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
4003 u16 start, u16 offset)
4005 skb->ip_summed = CHECKSUM_PARTIAL;
4006 skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
4007 skb->csum_offset = offset - start;
4010 /* Update skbuf and packet to reflect the remote checksum offload operation.
4011 * When called, ptr indicates the starting point for skb->csum when
4012 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
4013 * here, skb_postpull_rcsum is done so skb->csum start is ptr.
4015 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
4016 int start, int offset, bool nopartial)
4021 skb_remcsum_adjust_partial(skb, ptr, start, offset);
4025 if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
4026 __skb_checksum_complete(skb);
4027 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
4030 delta = remcsum_adjust(ptr, skb->csum, start, offset);
4032 /* Adjust skb->csum since we changed the packet */
4033 skb->csum = csum_add(skb->csum, delta);
4036 static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb)
4038 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
4039 return (void *)(skb->_nfct & NFCT_PTRMASK);
4045 static inline unsigned long skb_get_nfct(const struct sk_buff *skb)
4047 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
4054 static inline void skb_set_nfct(struct sk_buff *skb, unsigned long nfct)
4056 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
4061 #ifdef CONFIG_SKB_EXTENSIONS
4063 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4069 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
4072 SKB_EXT_NUM, /* must be last */
4076 * struct skb_ext - sk_buff extensions
4077 * @refcnt: 1 on allocation, deallocated on 0
4078 * @offset: offset to add to @data to obtain extension address
4079 * @chunks: size currently allocated, stored in SKB_EXT_ALIGN_SHIFT units
4080 * @data: start of extension data, variable sized
4082 * Note: offsets/lengths are stored in chunks of 8 bytes, this allows
4083 * to use 'u8' types while allowing up to 2kb worth of extension data.
4087 u8 offset[SKB_EXT_NUM]; /* in chunks of 8 bytes */
4088 u8 chunks; /* same */
4089 char data[0] __aligned(8);
4092 void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id);
4093 void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id);
4094 void __skb_ext_put(struct skb_ext *ext);
4096 static inline void skb_ext_put(struct sk_buff *skb)
4098 if (skb->active_extensions)
4099 __skb_ext_put(skb->extensions);
4102 static inline void __skb_ext_copy(struct sk_buff *dst,
4103 const struct sk_buff *src)
4105 dst->active_extensions = src->active_extensions;
4107 if (src->active_extensions) {
4108 struct skb_ext *ext = src->extensions;
4110 refcount_inc(&ext->refcnt);
4111 dst->extensions = ext;
4115 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src)
4118 __skb_ext_copy(dst, src);
4121 static inline bool __skb_ext_exist(const struct skb_ext *ext, enum skb_ext_id i)
4123 return !!ext->offset[i];
4126 static inline bool skb_ext_exist(const struct sk_buff *skb, enum skb_ext_id id)
4128 return skb->active_extensions & (1 << id);
4131 static inline void skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
4133 if (skb_ext_exist(skb, id))
4134 __skb_ext_del(skb, id);
4137 static inline void *skb_ext_find(const struct sk_buff *skb, enum skb_ext_id id)
4139 if (skb_ext_exist(skb, id)) {
4140 struct skb_ext *ext = skb->extensions;
4142 return (void *)ext + (ext->offset[id] << 3);
4148 static inline void skb_ext_put(struct sk_buff *skb) {}
4149 static inline void skb_ext_del(struct sk_buff *skb, int unused) {}
4150 static inline void __skb_ext_copy(struct sk_buff *d, const struct sk_buff *s) {}
4151 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *s) {}
4152 #endif /* CONFIG_SKB_EXTENSIONS */
4154 static inline void nf_reset(struct sk_buff *skb)
4156 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4157 nf_conntrack_put(skb_nfct(skb));
4160 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4161 skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
4165 static inline void nf_reset_trace(struct sk_buff *skb)
4167 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
4172 static inline void ipvs_reset(struct sk_buff *skb)
4174 #if IS_ENABLED(CONFIG_IP_VS)
4175 skb->ipvs_property = 0;
4179 /* Note: This doesn't put any conntrack info in dst. */
4180 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
4183 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4184 dst->_nfct = src->_nfct;
4185 nf_conntrack_get(skb_nfct(src));
4187 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
4189 dst->nf_trace = src->nf_trace;
4193 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
4195 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
4196 nf_conntrack_put(skb_nfct(dst));
4198 __nf_copy(dst, src, true);
4201 #ifdef CONFIG_NETWORK_SECMARK
4202 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
4204 to->secmark = from->secmark;
4207 static inline void skb_init_secmark(struct sk_buff *skb)
4212 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
4215 static inline void skb_init_secmark(struct sk_buff *skb)
4219 static inline int secpath_exists(const struct sk_buff *skb)
4222 return skb_ext_exist(skb, SKB_EXT_SEC_PATH);
4228 static inline bool skb_irq_freeable(const struct sk_buff *skb)
4230 return !skb->destructor &&
4231 !secpath_exists(skb) &&
4233 !skb->_skb_refdst &&
4234 !skb_has_frag_list(skb);
4237 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
4239 skb->queue_mapping = queue_mapping;
4242 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
4244 return skb->queue_mapping;
4247 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
4249 to->queue_mapping = from->queue_mapping;
4252 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
4254 skb->queue_mapping = rx_queue + 1;
4257 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
4259 return skb->queue_mapping - 1;
4262 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
4264 return skb->queue_mapping != 0;
4267 static inline void skb_set_dst_pending_confirm(struct sk_buff *skb, u32 val)
4269 skb->dst_pending_confirm = val;
4272 static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb)
4274 return skb->dst_pending_confirm != 0;
4277 static inline struct sec_path *skb_sec_path(const struct sk_buff *skb)
4280 return skb_ext_find(skb, SKB_EXT_SEC_PATH);
4286 /* Keeps track of mac header offset relative to skb->head.
4287 * It is useful for TSO of Tunneling protocol. e.g. GRE.
4288 * For non-tunnel skb it points to skb_mac_header() and for
4289 * tunnel skb it points to outer mac header.
4290 * Keeps track of level of encapsulation of network headers.
4301 #define SKB_SGO_CB_OFFSET 32
4302 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
4304 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
4306 return (skb_mac_header(inner_skb) - inner_skb->head) -
4307 SKB_GSO_CB(inner_skb)->mac_offset;
4310 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
4312 int new_headroom, headroom;
4315 headroom = skb_headroom(skb);
4316 ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
4320 new_headroom = skb_headroom(skb);
4321 SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
4325 static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
4327 /* Do not update partial checksums if remote checksum is enabled. */
4328 if (skb->remcsum_offload)
4331 SKB_GSO_CB(skb)->csum = res;
4332 SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
4335 /* Compute the checksum for a gso segment. First compute the checksum value
4336 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
4337 * then add in skb->csum (checksum from csum_start to end of packet).
4338 * skb->csum and csum_start are then updated to reflect the checksum of the
4339 * resultant packet starting from the transport header-- the resultant checksum
4340 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
4343 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
4345 unsigned char *csum_start = skb_transport_header(skb);
4346 int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
4347 __wsum partial = SKB_GSO_CB(skb)->csum;
4349 SKB_GSO_CB(skb)->csum = res;
4350 SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
4352 return csum_fold(csum_partial(csum_start, plen, partial));
4355 static inline bool skb_is_gso(const struct sk_buff *skb)
4357 return skb_shinfo(skb)->gso_size;
4360 /* Note: Should be called only if skb_is_gso(skb) is true */
4361 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
4363 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
4366 /* Note: Should be called only if skb_is_gso(skb) is true */
4367 static inline bool skb_is_gso_sctp(const struct sk_buff *skb)
4369 return skb_shinfo(skb)->gso_type & SKB_GSO_SCTP;
4372 /* Note: Should be called only if skb_is_gso(skb) is true */
4373 static inline bool skb_is_gso_tcp(const struct sk_buff *skb)
4375 return skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6);
4378 static inline void skb_gso_reset(struct sk_buff *skb)
4380 skb_shinfo(skb)->gso_size = 0;
4381 skb_shinfo(skb)->gso_segs = 0;
4382 skb_shinfo(skb)->gso_type = 0;
4385 static inline void skb_increase_gso_size(struct skb_shared_info *shinfo,
4388 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
4390 shinfo->gso_size += increment;
4393 static inline void skb_decrease_gso_size(struct skb_shared_info *shinfo,
4396 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
4398 shinfo->gso_size -= decrement;
4401 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
4403 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
4405 /* LRO sets gso_size but not gso_type, whereas if GSO is really
4406 * wanted then gso_type will be set. */
4407 const struct skb_shared_info *shinfo = skb_shinfo(skb);
4409 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
4410 unlikely(shinfo->gso_type == 0)) {
4411 __skb_warn_lro_forwarding(skb);
4417 static inline void skb_forward_csum(struct sk_buff *skb)
4419 /* Unfortunately we don't support this one. Any brave souls? */
4420 if (skb->ip_summed == CHECKSUM_COMPLETE)
4421 skb->ip_summed = CHECKSUM_NONE;
4425 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
4426 * @skb: skb to check
4428 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
4429 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
4430 * use this helper, to document places where we make this assertion.
4432 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
4435 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
4439 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
4441 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
4442 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
4443 unsigned int transport_len,
4444 __sum16(*skb_chkf)(struct sk_buff *skb));
4447 * skb_head_is_locked - Determine if the skb->head is locked down
4448 * @skb: skb to check
4450 * The head on skbs build around a head frag can be removed if they are
4451 * not cloned. This function returns true if the skb head is locked down
4452 * due to either being allocated via kmalloc, or by being a clone with
4453 * multiple references to the head.
4455 static inline bool skb_head_is_locked(const struct sk_buff *skb)
4457 return !skb->head_frag || skb_cloned(skb);
4460 /* Local Checksum Offload.
4461 * Compute outer checksum based on the assumption that the
4462 * inner checksum will be offloaded later.
4463 * See Documentation/networking/checksum-offloads.rst for
4464 * explanation of how this works.
4465 * Fill in outer checksum adjustment (e.g. with sum of outer
4466 * pseudo-header) before calling.
4467 * Also ensure that inner checksum is in linear data area.
4469 static inline __wsum lco_csum(struct sk_buff *skb)
4471 unsigned char *csum_start = skb_checksum_start(skb);
4472 unsigned char *l4_hdr = skb_transport_header(skb);
4475 /* Start with complement of inner checksum adjustment */
4476 partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
4479 /* Add in checksum of our headers (incl. outer checksum
4480 * adjustment filled in by caller) and return result.
4482 return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
4485 #endif /* __KERNEL__ */
4486 #endif /* _LINUX_SKBUFF_H */