2 * Definitions for the 'struct sk_buff' memory handlers.
5 * Alan Cox, <gw4pts@gw4pts.ampr.org>
6 * Florian La Roche, <rzsfl@rz.uni-sb.de>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
17 #include <linux/kernel.h>
18 #include <linux/kmemcheck.h>
19 #include <linux/compiler.h>
20 #include <linux/time.h>
21 #include <linux/bug.h>
22 #include <linux/cache.h>
23 #include <linux/rbtree.h>
24 #include <linux/socket.h>
26 #include <linux/atomic.h>
27 #include <asm/types.h>
28 #include <linux/spinlock.h>
29 #include <linux/net.h>
30 #include <linux/textsearch.h>
31 #include <net/checksum.h>
32 #include <linux/rcupdate.h>
33 #include <linux/hrtimer.h>
34 #include <linux/dma-mapping.h>
35 #include <linux/netdev_features.h>
36 #include <linux/sched.h>
37 #include <linux/sched/clock.h>
38 #include <net/flow_dissector.h>
39 #include <linux/splice.h>
40 #include <linux/in6.h>
41 #include <linux/if_packet.h>
44 /* The interface for checksum offload between the stack and networking drivers
47 * A. IP checksum related features
49 * Drivers advertise checksum offload capabilities in the features of a device.
50 * From the stack's point of view these are capabilities offered by the driver,
51 * a driver typically only advertises features that it is capable of offloading
54 * The checksum related features are:
56 * NETIF_F_HW_CSUM - The driver (or its device) is able to compute one
57 * IP (one's complement) checksum for any combination
58 * of protocols or protocol layering. The checksum is
59 * computed and set in a packet per the CHECKSUM_PARTIAL
60 * interface (see below).
62 * NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain
63 * TCP or UDP packets over IPv4. These are specifically
64 * unencapsulated packets of the form IPv4|TCP or
65 * IPv4|UDP where the Protocol field in the IPv4 header
66 * is TCP or UDP. The IPv4 header may contain IP options
67 * This feature cannot be set in features for a device
68 * with NETIF_F_HW_CSUM also set. This feature is being
69 * DEPRECATED (see below).
71 * NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain
72 * TCP or UDP packets over IPv6. These are specifically
73 * unencapsulated packets of the form IPv6|TCP or
74 * IPv4|UDP where the Next Header field in the IPv6
75 * header is either TCP or UDP. IPv6 extension headers
76 * are not supported with this feature. This feature
77 * cannot be set in features for a device with
78 * NETIF_F_HW_CSUM also set. This feature is being
79 * DEPRECATED (see below).
81 * NETIF_F_RXCSUM - Driver (device) performs receive checksum offload.
82 * This flag is used only used to disable the RX checksum
83 * feature for a device. The stack will accept receive
84 * checksum indication in packets received on a device
85 * regardless of whether NETIF_F_RXCSUM is set.
87 * B. Checksumming of received packets by device. Indication of checksum
88 * verification is in set skb->ip_summed. Possible values are:
92 * Device did not checksum this packet e.g. due to lack of capabilities.
93 * The packet contains full (though not verified) checksum in packet but
94 * not in skb->csum. Thus, skb->csum is undefined in this case.
96 * CHECKSUM_UNNECESSARY:
98 * The hardware you're dealing with doesn't calculate the full checksum
99 * (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
100 * for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
101 * if their checksums are okay. skb->csum is still undefined in this case
102 * though. A driver or device must never modify the checksum field in the
103 * packet even if checksum is verified.
105 * CHECKSUM_UNNECESSARY is applicable to following protocols:
106 * TCP: IPv6 and IPv4.
107 * UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
108 * zero UDP checksum for either IPv4 or IPv6, the networking stack
109 * may perform further validation in this case.
110 * GRE: only if the checksum is present in the header.
111 * SCTP: indicates the CRC in SCTP header has been validated.
113 * skb->csum_level indicates the number of consecutive checksums found in
114 * the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
115 * For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
116 * and a device is able to verify the checksums for UDP (possibly zero),
117 * GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
118 * two. If the device were only able to verify the UDP checksum and not
119 * GRE, either because it doesn't support GRE checksum of because GRE
120 * checksum is bad, skb->csum_level would be set to zero (TCP checksum is
121 * not considered in this case).
125 * This is the most generic way. The device supplied checksum of the _whole_
126 * packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
127 * hardware doesn't need to parse L3/L4 headers to implement this.
129 * Note: Even if device supports only some protocols, but is able to produce
130 * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
134 * A checksum is set up to be offloaded to a device as described in the
135 * output description for CHECKSUM_PARTIAL. This may occur on a packet
136 * received directly from another Linux OS, e.g., a virtualized Linux kernel
137 * on the same host, or it may be set in the input path in GRO or remote
138 * checksum offload. For the purposes of checksum verification, the checksum
139 * referred to by skb->csum_start + skb->csum_offset and any preceding
140 * checksums in the packet are considered verified. Any checksums in the
141 * packet that are after the checksum being offloaded are not considered to
144 * C. Checksumming on transmit for non-GSO. The stack requests checksum offload
145 * in the skb->ip_summed for a packet. Values are:
149 * The driver is required to checksum the packet as seen by hard_start_xmit()
150 * from skb->csum_start up to the end, and to record/write the checksum at
151 * offset skb->csum_start + skb->csum_offset. A driver may verify that the
152 * csum_start and csum_offset values are valid values given the length and
153 * offset of the packet, however they should not attempt to validate that the
154 * checksum refers to a legitimate transport layer checksum-- it is the
155 * purview of the stack to validate that csum_start and csum_offset are set
158 * When the stack requests checksum offload for a packet, the driver MUST
159 * ensure that the checksum is set correctly. A driver can either offload the
160 * checksum calculation to the device, or call skb_checksum_help (in the case
161 * that the device does not support offload for a particular checksum).
163 * NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of
164 * NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate
165 * checksum offload capability. If a device has limited checksum capabilities
166 * (for instance can only perform NETIF_F_IP_CSUM or NETIF_F_IPV6_CSUM as
167 * described above) a helper function can be called to resolve
168 * CHECKSUM_PARTIAL. The helper functions are skb_csum_off_chk*. The helper
169 * function takes a spec argument that describes the protocol layer that is
170 * supported for checksum offload and can be called for each packet. If a
171 * packet does not match the specification for offload, skb_checksum_help
172 * 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 ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
193 * accordingly. Note the there is no indication in the skbuff that the
194 * CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports
195 * both IP checksum offload and SCTP CRC offload must verify which offload
196 * is configured for a packet presumably by inspecting packet headers.
198 * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
199 * offloading the FCOE CRC in a packet. To perform this offload the stack
200 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
201 * accordingly. Note the there is no indication in the skbuff that the
202 * CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports
203 * both IP checksum offload and FCOE CRC offload must verify which offload
204 * is configured for a packet presumably by inspecting packet headers.
206 * E. Checksumming on output with GSO.
208 * In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload
209 * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
210 * gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as
211 * part of the GSO operation is implied. If a checksum is being offloaded
212 * with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset
213 * are set to refer to the outermost checksum being offload (two offloaded
214 * checksums are possible with UDP encapsulation).
217 /* Don't change this without changing skb_csum_unnecessary! */
218 #define CHECKSUM_NONE 0
219 #define CHECKSUM_UNNECESSARY 1
220 #define CHECKSUM_COMPLETE 2
221 #define CHECKSUM_PARTIAL 3
223 /* Maximum value in skb->csum_level */
224 #define SKB_MAX_CSUM_LEVEL 3
226 #define SKB_DATA_ALIGN(X) ALIGN(X, SMP_CACHE_BYTES)
227 #define SKB_WITH_OVERHEAD(X) \
228 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
229 #define SKB_MAX_ORDER(X, ORDER) \
230 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
231 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
232 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
234 /* return minimum truesize of one skb containing X bytes of data */
235 #define SKB_TRUESIZE(X) ((X) + \
236 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
237 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
241 struct pipe_inode_info
;
245 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
246 struct nf_conntrack
{
251 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
252 struct nf_bridge_info
{
255 BRNF_PROTO_UNCHANGED
,
263 struct net_device
*physindev
;
265 /* always valid & non-NULL from FORWARD on, for physdev match */
266 struct net_device
*physoutdev
;
268 /* prerouting: detect dnat in orig/reply direction */
270 struct in6_addr ipv6_daddr
;
272 /* after prerouting + nat detected: store original source
273 * mac since neigh resolution overwrites it, only used while
274 * skb is out in neigh layer.
276 char neigh_header
[8];
281 struct sk_buff_head
{
282 /* These two members must be first. */
283 struct sk_buff
*next
;
284 struct sk_buff
*prev
;
292 /* To allow 64K frame to be packed as single skb without frag_list we
293 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
294 * buffers which do not start on a page boundary.
296 * Since GRO uses frags we allocate at least 16 regardless of page
299 #if (65536/PAGE_SIZE + 1) < 16
300 #define MAX_SKB_FRAGS 16UL
302 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
304 extern int sysctl_max_skb_frags
;
306 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
307 * segment using its current segmentation instead.
309 #define GSO_BY_FRAGS 0xFFFF
311 typedef struct skb_frag_struct skb_frag_t
;
313 struct skb_frag_struct
{
317 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
326 static inline unsigned int skb_frag_size(const skb_frag_t
*frag
)
331 static inline void skb_frag_size_set(skb_frag_t
*frag
, unsigned int size
)
336 static inline void skb_frag_size_add(skb_frag_t
*frag
, int delta
)
341 static inline void skb_frag_size_sub(skb_frag_t
*frag
, int delta
)
346 #define HAVE_HW_TIME_STAMP
349 * struct skb_shared_hwtstamps - hardware time stamps
350 * @hwtstamp: hardware time stamp transformed into duration
351 * since arbitrary point in time
353 * Software time stamps generated by ktime_get_real() are stored in
356 * hwtstamps can only be compared against other hwtstamps from
359 * This structure is attached to packets as part of the
360 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
362 struct skb_shared_hwtstamps
{
366 /* Definitions for tx_flags in struct skb_shared_info */
368 /* generate hardware time stamp */
369 SKBTX_HW_TSTAMP
= 1 << 0,
371 /* generate software time stamp when queueing packet to NIC */
372 SKBTX_SW_TSTAMP
= 1 << 1,
374 /* device driver is going to provide hardware time stamp */
375 SKBTX_IN_PROGRESS
= 1 << 2,
377 /* device driver supports TX zero-copy buffers */
378 SKBTX_DEV_ZEROCOPY
= 1 << 3,
380 /* generate wifi status information (where possible) */
381 SKBTX_WIFI_STATUS
= 1 << 4,
383 /* This indicates at least one fragment might be overwritten
384 * (as in vmsplice(), sendfile() ...)
385 * If we need to compute a TX checksum, we'll need to copy
386 * all frags to avoid possible bad checksum
388 SKBTX_SHARED_FRAG
= 1 << 5,
390 /* generate software time stamp when entering packet scheduling */
391 SKBTX_SCHED_TSTAMP
= 1 << 6,
394 #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
396 #define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
399 * The callback notifies userspace to release buffers when skb DMA is done in
400 * lower device, the skb last reference should be 0 when calling this.
401 * The zerocopy_success argument is true if zero copy transmit occurred,
402 * false on data copy or out of memory error caused by data copy attempt.
403 * The ctx field is used to track device context.
404 * The desc field is used to track userspace buffer index.
407 void (*callback
)(struct ubuf_info
*, bool zerocopy_success
);
412 /* This data is invariant across clones and lives at
413 * the end of the header data, ie. at skb->end.
415 struct skb_shared_info
{
416 unsigned short _unused
;
417 unsigned char nr_frags
;
419 unsigned short gso_size
;
420 /* Warning: this field is not always filled in (UFO)! */
421 unsigned short gso_segs
;
422 struct sk_buff
*frag_list
;
423 struct skb_shared_hwtstamps hwtstamps
;
424 unsigned int gso_type
;
429 * Warning : all fields before dataref are cleared in __alloc_skb()
433 /* Intermediate layers must ensure that destructor_arg
434 * remains valid until skb destructor */
435 void * destructor_arg
;
437 /* must be last field, see pskb_expand_head() */
438 skb_frag_t frags
[MAX_SKB_FRAGS
];
441 /* We divide dataref into two halves. The higher 16 bits hold references
442 * to the payload part of skb->data. The lower 16 bits hold references to
443 * the entire skb->data. A clone of a headerless skb holds the length of
444 * the header in skb->hdr_len.
446 * All users must obey the rule that the skb->data reference count must be
447 * greater than or equal to the payload reference count.
449 * Holding a reference to the payload part means that the user does not
450 * care about modifications to the header part of skb->data.
452 #define SKB_DATAREF_SHIFT 16
453 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
457 SKB_FCLONE_UNAVAILABLE
, /* skb has no fclone (from head_cache) */
458 SKB_FCLONE_ORIG
, /* orig skb (from fclone_cache) */
459 SKB_FCLONE_CLONE
, /* companion fclone skb (from fclone_cache) */
463 SKB_GSO_TCPV4
= 1 << 0,
464 SKB_GSO_UDP
= 1 << 1,
466 /* This indicates the skb is from an untrusted source. */
467 SKB_GSO_DODGY
= 1 << 2,
469 /* This indicates the tcp segment has CWR set. */
470 SKB_GSO_TCP_ECN
= 1 << 3,
472 SKB_GSO_TCP_FIXEDID
= 1 << 4,
474 SKB_GSO_TCPV6
= 1 << 5,
476 SKB_GSO_FCOE
= 1 << 6,
478 SKB_GSO_GRE
= 1 << 7,
480 SKB_GSO_GRE_CSUM
= 1 << 8,
482 SKB_GSO_IPXIP4
= 1 << 9,
484 SKB_GSO_IPXIP6
= 1 << 10,
486 SKB_GSO_UDP_TUNNEL
= 1 << 11,
488 SKB_GSO_UDP_TUNNEL_CSUM
= 1 << 12,
490 SKB_GSO_PARTIAL
= 1 << 13,
492 SKB_GSO_TUNNEL_REMCSUM
= 1 << 14,
494 SKB_GSO_SCTP
= 1 << 15,
496 SKB_GSO_ESP
= 1 << 16,
499 #if BITS_PER_LONG > 32
500 #define NET_SKBUFF_DATA_USES_OFFSET 1
503 #ifdef NET_SKBUFF_DATA_USES_OFFSET
504 typedef unsigned int sk_buff_data_t
;
506 typedef unsigned char *sk_buff_data_t
;
510 * struct skb_mstamp - multi resolution time stamps
511 * @stamp_us: timestamp in us resolution
512 * @stamp_jiffies: timestamp in jiffies
525 * skb_mstamp_get - get current timestamp
526 * @cl: place to store timestamps
528 static inline void skb_mstamp_get(struct skb_mstamp
*cl
)
530 u64 val
= local_clock();
532 do_div(val
, NSEC_PER_USEC
);
533 cl
->stamp_us
= (u32
)val
;
534 cl
->stamp_jiffies
= (u32
)jiffies
;
538 * skb_mstamp_delta - compute the difference in usec between two skb_mstamp
539 * @t1: pointer to newest sample
540 * @t0: pointer to oldest sample
542 static inline u32
skb_mstamp_us_delta(const struct skb_mstamp
*t1
,
543 const struct skb_mstamp
*t0
)
545 s32 delta_us
= t1
->stamp_us
- t0
->stamp_us
;
546 u32 delta_jiffies
= t1
->stamp_jiffies
- t0
->stamp_jiffies
;
548 /* If delta_us is negative, this might be because interval is too big,
549 * or local_clock() drift is too big : fallback using jiffies.
552 delta_jiffies
>= (INT_MAX
/ (USEC_PER_SEC
/ HZ
)))
554 delta_us
= jiffies_to_usecs(delta_jiffies
);
559 static inline bool skb_mstamp_after(const struct skb_mstamp
*t1
,
560 const struct skb_mstamp
*t0
)
562 s32 diff
= t1
->stamp_jiffies
- t0
->stamp_jiffies
;
565 diff
= t1
->stamp_us
- t0
->stamp_us
;
570 * struct sk_buff - socket buffer
571 * @next: Next buffer in list
572 * @prev: Previous buffer in list
573 * @tstamp: Time we arrived/left
574 * @rbnode: RB tree node, alternative to next/prev for netem/tcp
575 * @sk: Socket we are owned by
576 * @dev: Device we arrived on/are leaving by
577 * @cb: Control buffer. Free for use by every layer. Put private vars here
578 * @_skb_refdst: destination entry (with norefcount bit)
579 * @sp: the security path, used for xfrm
580 * @len: Length of actual data
581 * @data_len: Data length
582 * @mac_len: Length of link layer header
583 * @hdr_len: writable header length of cloned skb
584 * @csum: Checksum (must include start/offset pair)
585 * @csum_start: Offset from skb->head where checksumming should start
586 * @csum_offset: Offset from csum_start where checksum should be stored
587 * @priority: Packet queueing priority
588 * @ignore_df: allow local fragmentation
589 * @cloned: Head may be cloned (check refcnt to be sure)
590 * @ip_summed: Driver fed us an IP checksum
591 * @nohdr: Payload reference only, must not modify header
592 * @pkt_type: Packet class
593 * @fclone: skbuff clone status
594 * @ipvs_property: skbuff is owned by ipvs
595 * @tc_skip_classify: do not classify packet. set by IFB device
596 * @tc_at_ingress: used within tc_classify to distinguish in/egress
597 * @tc_redirected: packet was redirected by a tc action
598 * @tc_from_ingress: if tc_redirected, tc_at_ingress at time of redirect
599 * @peeked: this packet has been seen already, so stats have been
600 * done for it, don't do them again
601 * @nf_trace: netfilter packet trace flag
602 * @protocol: Packet protocol from driver
603 * @destructor: Destruct function
604 * @_nfct: Associated connection, if any (with nfctinfo bits)
605 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
606 * @skb_iif: ifindex of device we arrived on
607 * @tc_index: Traffic control index
608 * @hash: the packet hash
609 * @queue_mapping: Queue mapping for multiqueue devices
610 * @xmit_more: More SKBs are pending for this queue
611 * @ndisc_nodetype: router type (from link layer)
612 * @ooo_okay: allow the mapping of a socket to a queue to be changed
613 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport
615 * @sw_hash: indicates hash was computed in software stack
616 * @wifi_acked_valid: wifi_acked was set
617 * @wifi_acked: whether frame was acked on wifi or not
618 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
619 * @dst_pending_confirm: need to confirm neighbour
620 * @napi_id: id of the NAPI struct this skb came from
621 * @secmark: security marking
622 * @mark: Generic packet mark
623 * @vlan_proto: vlan encapsulation protocol
624 * @vlan_tci: vlan tag control information
625 * @inner_protocol: Protocol (encapsulation)
626 * @inner_transport_header: Inner transport layer header (encapsulation)
627 * @inner_network_header: Network layer header (encapsulation)
628 * @inner_mac_header: Link layer header (encapsulation)
629 * @transport_header: Transport layer header
630 * @network_header: Network layer header
631 * @mac_header: Link layer header
632 * @tail: Tail pointer
634 * @head: Head of buffer
635 * @data: Data head pointer
636 * @truesize: Buffer size
637 * @users: User count - see {datagram,tcp}.c
643 /* These two members must be first. */
644 struct sk_buff
*next
;
645 struct sk_buff
*prev
;
649 struct skb_mstamp skb_mstamp
;
652 struct rb_node rbnode
; /* used in netem & tcp stack */
657 struct net_device
*dev
;
658 /* Some protocols might use this space to store information,
659 * while device pointer would be NULL.
660 * UDP receive path is one user.
662 unsigned long dev_scratch
;
665 * This is the control buffer. It is free to use for every
666 * layer. Please put your private variables there. If you
667 * want to keep them across layers you have to do a skb_clone()
668 * first. This is owned by whoever has the skb queued ATM.
670 char cb
[48] __aligned(8);
672 unsigned long _skb_refdst
;
673 void (*destructor
)(struct sk_buff
*skb
);
677 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
680 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
681 struct nf_bridge_info
*nf_bridge
;
688 /* Following fields are _not_ copied in __copy_skb_header()
689 * Note that queue_mapping is here mostly to fill a hole.
691 kmemcheck_bitfield_begin(flags1
);
694 /* if you move cloned around you also must adapt those constants */
695 #ifdef __BIG_ENDIAN_BITFIELD
696 #define CLONED_MASK (1 << 7)
698 #define CLONED_MASK 1
700 #define CLONED_OFFSET() offsetof(struct sk_buff, __cloned_offset)
702 __u8 __cloned_offset
[0];
709 __unused
:1; /* one bit hole */
710 kmemcheck_bitfield_end(flags1
);
712 /* fields enclosed in headers_start/headers_end are copied
713 * using a single memcpy() in __copy_skb_header()
716 __u32 headers_start
[0];
719 /* if you move pkt_type around you also must adapt those constants */
720 #ifdef __BIG_ENDIAN_BITFIELD
721 #define PKT_TYPE_MAX (7 << 5)
723 #define PKT_TYPE_MAX 7
725 #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
727 __u8 __pkt_type_offset
[0];
737 __u8 wifi_acked_valid
:1;
741 /* Indicates the inner headers are valid in the skbuff. */
742 __u8 encapsulation
:1;
743 __u8 encap_hdr_csum
:1;
745 __u8 csum_complete_sw
:1;
749 __u8 dst_pending_confirm
:1;
750 #ifdef CONFIG_IPV6_NDISC_NODETYPE
751 __u8 ndisc_nodetype
:2;
753 __u8 ipvs_property
:1;
754 __u8 inner_protocol_type
:1;
755 __u8 remcsum_offload
:1;
756 #ifdef CONFIG_NET_SWITCHDEV
757 __u8 offload_fwd_mark
:1;
759 #ifdef CONFIG_NET_CLS_ACT
760 __u8 tc_skip_classify
:1;
761 __u8 tc_at_ingress
:1;
762 __u8 tc_redirected
:1;
763 __u8 tc_from_ingress
:1;
766 #ifdef CONFIG_NET_SCHED
767 __u16 tc_index
; /* traffic control index */
782 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
784 unsigned int napi_id
;
785 unsigned int sender_cpu
;
788 #ifdef CONFIG_NETWORK_SECMARK
794 __u32 reserved_tailroom
;
798 __be16 inner_protocol
;
802 __u16 inner_transport_header
;
803 __u16 inner_network_header
;
804 __u16 inner_mac_header
;
807 __u16 transport_header
;
808 __u16 network_header
;
812 __u32 headers_end
[0];
815 /* These elements must be at the end, see alloc_skb() for details. */
820 unsigned int truesize
;
826 * Handling routines are only of interest to the kernel
828 #include <linux/slab.h>
831 #define SKB_ALLOC_FCLONE 0x01
832 #define SKB_ALLOC_RX 0x02
833 #define SKB_ALLOC_NAPI 0x04
835 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
836 static inline bool skb_pfmemalloc(const struct sk_buff
*skb
)
838 return unlikely(skb
->pfmemalloc
);
842 * skb might have a dst pointer attached, refcounted or not.
843 * _skb_refdst low order bit is set if refcount was _not_ taken
845 #define SKB_DST_NOREF 1UL
846 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
848 #define SKB_NFCT_PTRMASK ~(7UL)
850 * skb_dst - returns skb dst_entry
853 * Returns skb dst_entry, regardless of reference taken or not.
855 static inline struct dst_entry
*skb_dst(const struct sk_buff
*skb
)
857 /* If refdst was not refcounted, check we still are in a
858 * rcu_read_lock section
860 WARN_ON((skb
->_skb_refdst
& SKB_DST_NOREF
) &&
861 !rcu_read_lock_held() &&
862 !rcu_read_lock_bh_held());
863 return (struct dst_entry
*)(skb
->_skb_refdst
& SKB_DST_PTRMASK
);
867 * skb_dst_set - sets skb dst
871 * Sets skb dst, assuming a reference was taken on dst and should
872 * be released by skb_dst_drop()
874 static inline void skb_dst_set(struct sk_buff
*skb
, struct dst_entry
*dst
)
876 skb
->_skb_refdst
= (unsigned long)dst
;
880 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
884 * Sets skb dst, assuming a reference was not taken on dst.
885 * If dst entry is cached, we do not take reference and dst_release
886 * will be avoided by refdst_drop. If dst entry is not cached, we take
887 * reference, so that last dst_release can destroy the dst immediately.
889 static inline void skb_dst_set_noref(struct sk_buff
*skb
, struct dst_entry
*dst
)
891 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
892 skb
->_skb_refdst
= (unsigned long)dst
| SKB_DST_NOREF
;
896 * skb_dst_is_noref - Test if skb dst isn't refcounted
899 static inline bool skb_dst_is_noref(const struct sk_buff
*skb
)
901 return (skb
->_skb_refdst
& SKB_DST_NOREF
) && skb_dst(skb
);
904 static inline struct rtable
*skb_rtable(const struct sk_buff
*skb
)
906 return (struct rtable
*)skb_dst(skb
);
909 /* For mangling skb->pkt_type from user space side from applications
910 * such as nft, tc, etc, we only allow a conservative subset of
911 * possible pkt_types to be set.
913 static inline bool skb_pkt_type_ok(u32 ptype
)
915 return ptype
<= PACKET_OTHERHOST
;
918 void kfree_skb(struct sk_buff
*skb
);
919 void kfree_skb_list(struct sk_buff
*segs
);
920 void skb_tx_error(struct sk_buff
*skb
);
921 void consume_skb(struct sk_buff
*skb
);
922 void __kfree_skb(struct sk_buff
*skb
);
923 extern struct kmem_cache
*skbuff_head_cache
;
925 void kfree_skb_partial(struct sk_buff
*skb
, bool head_stolen
);
926 bool skb_try_coalesce(struct sk_buff
*to
, struct sk_buff
*from
,
927 bool *fragstolen
, int *delta_truesize
);
929 struct sk_buff
*__alloc_skb(unsigned int size
, gfp_t priority
, int flags
,
931 struct sk_buff
*__build_skb(void *data
, unsigned int frag_size
);
932 struct sk_buff
*build_skb(void *data
, unsigned int frag_size
);
933 static inline struct sk_buff
*alloc_skb(unsigned int size
,
936 return __alloc_skb(size
, priority
, 0, NUMA_NO_NODE
);
939 struct sk_buff
*alloc_skb_with_frags(unsigned long header_len
,
940 unsigned long data_len
,
945 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
946 struct sk_buff_fclones
{
955 * skb_fclone_busy - check if fclone is busy
959 * Returns true if skb is a fast clone, and its clone is not freed.
960 * Some drivers call skb_orphan() in their ndo_start_xmit(),
961 * so we also check that this didnt happen.
963 static inline bool skb_fclone_busy(const struct sock
*sk
,
964 const struct sk_buff
*skb
)
966 const struct sk_buff_fclones
*fclones
;
968 fclones
= container_of(skb
, struct sk_buff_fclones
, skb1
);
970 return skb
->fclone
== SKB_FCLONE_ORIG
&&
971 atomic_read(&fclones
->fclone_ref
) > 1 &&
972 fclones
->skb2
.sk
== sk
;
975 static inline struct sk_buff
*alloc_skb_fclone(unsigned int size
,
978 return __alloc_skb(size
, priority
, SKB_ALLOC_FCLONE
, NUMA_NO_NODE
);
981 struct sk_buff
*__alloc_skb_head(gfp_t priority
, int node
);
982 static inline struct sk_buff
*alloc_skb_head(gfp_t priority
)
984 return __alloc_skb_head(priority
, -1);
987 struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
);
988 int skb_copy_ubufs(struct sk_buff
*skb
, gfp_t gfp_mask
);
989 struct sk_buff
*skb_clone(struct sk_buff
*skb
, gfp_t priority
);
990 struct sk_buff
*skb_copy(const struct sk_buff
*skb
, gfp_t priority
);
991 struct sk_buff
*__pskb_copy_fclone(struct sk_buff
*skb
, int headroom
,
992 gfp_t gfp_mask
, bool fclone
);
993 static inline struct sk_buff
*__pskb_copy(struct sk_buff
*skb
, int headroom
,
996 return __pskb_copy_fclone(skb
, headroom
, gfp_mask
, false);
999 int pskb_expand_head(struct sk_buff
*skb
, int nhead
, int ntail
, gfp_t gfp_mask
);
1000 struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
,
1001 unsigned int headroom
);
1002 struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
, int newheadroom
,
1003 int newtailroom
, gfp_t priority
);
1004 int skb_to_sgvec_nomark(struct sk_buff
*skb
, struct scatterlist
*sg
,
1005 int offset
, int len
);
1006 int skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
,
1008 int skb_cow_data(struct sk_buff
*skb
, int tailbits
, struct sk_buff
**trailer
);
1009 int skb_pad(struct sk_buff
*skb
, int pad
);
1010 #define dev_kfree_skb(a) consume_skb(a)
1012 int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
1013 int getfrag(void *from
, char *to
, int offset
,
1014 int len
, int odd
, struct sk_buff
*skb
),
1015 void *from
, int length
);
1017 int skb_append_pagefrags(struct sk_buff
*skb
, struct page
*page
,
1018 int offset
, size_t size
);
1020 struct skb_seq_state
{
1024 __u32 stepped_offset
;
1025 struct sk_buff
*root_skb
;
1026 struct sk_buff
*cur_skb
;
1030 void skb_prepare_seq_read(struct sk_buff
*skb
, unsigned int from
,
1031 unsigned int to
, struct skb_seq_state
*st
);
1032 unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
1033 struct skb_seq_state
*st
);
1034 void skb_abort_seq_read(struct skb_seq_state
*st
);
1036 unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
1037 unsigned int to
, struct ts_config
*config
);
1040 * Packet hash types specify the type of hash in skb_set_hash.
1042 * Hash types refer to the protocol layer addresses which are used to
1043 * construct a packet's hash. The hashes are used to differentiate or identify
1044 * flows of the protocol layer for the hash type. Hash types are either
1045 * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1047 * Properties of hashes:
1049 * 1) Two packets in different flows have different hash values
1050 * 2) Two packets in the same flow should have the same hash value
1052 * A hash at a higher layer is considered to be more specific. A driver should
1053 * set the most specific hash possible.
1055 * A driver cannot indicate a more specific hash than the layer at which a hash
1056 * was computed. For instance an L3 hash cannot be set as an L4 hash.
1058 * A driver may indicate a hash level which is less specific than the
1059 * actual layer the hash was computed on. For instance, a hash computed
1060 * at L4 may be considered an L3 hash. This should only be done if the
1061 * driver can't unambiguously determine that the HW computed the hash at
1062 * the higher layer. Note that the "should" in the second property above
1065 enum pkt_hash_types
{
1066 PKT_HASH_TYPE_NONE
, /* Undefined type */
1067 PKT_HASH_TYPE_L2
, /* Input: src_MAC, dest_MAC */
1068 PKT_HASH_TYPE_L3
, /* Input: src_IP, dst_IP */
1069 PKT_HASH_TYPE_L4
, /* Input: src_IP, dst_IP, src_port, dst_port */
1072 static inline void skb_clear_hash(struct sk_buff
*skb
)
1079 static inline void skb_clear_hash_if_not_l4(struct sk_buff
*skb
)
1082 skb_clear_hash(skb
);
1086 __skb_set_hash(struct sk_buff
*skb
, __u32 hash
, bool is_sw
, bool is_l4
)
1088 skb
->l4_hash
= is_l4
;
1089 skb
->sw_hash
= is_sw
;
1094 skb_set_hash(struct sk_buff
*skb
, __u32 hash
, enum pkt_hash_types type
)
1096 /* Used by drivers to set hash from HW */
1097 __skb_set_hash(skb
, hash
, false, type
== PKT_HASH_TYPE_L4
);
1101 __skb_set_sw_hash(struct sk_buff
*skb
, __u32 hash
, bool is_l4
)
1103 __skb_set_hash(skb
, hash
, true, is_l4
);
1106 void __skb_get_hash(struct sk_buff
*skb
);
1107 u32
__skb_get_hash_symmetric(const struct sk_buff
*skb
);
1108 u32
skb_get_poff(const struct sk_buff
*skb
);
1109 u32
__skb_get_poff(const struct sk_buff
*skb
, void *data
,
1110 const struct flow_keys
*keys
, int hlen
);
1111 __be32
__skb_flow_get_ports(const struct sk_buff
*skb
, int thoff
, u8 ip_proto
,
1112 void *data
, int hlen_proto
);
1114 static inline __be32
skb_flow_get_ports(const struct sk_buff
*skb
,
1115 int thoff
, u8 ip_proto
)
1117 return __skb_flow_get_ports(skb
, thoff
, ip_proto
, NULL
, 0);
1120 void skb_flow_dissector_init(struct flow_dissector
*flow_dissector
,
1121 const struct flow_dissector_key
*key
,
1122 unsigned int key_count
);
1124 bool __skb_flow_dissect(const struct sk_buff
*skb
,
1125 struct flow_dissector
*flow_dissector
,
1126 void *target_container
,
1127 void *data
, __be16 proto
, int nhoff
, int hlen
,
1128 unsigned int flags
);
1130 static inline bool skb_flow_dissect(const struct sk_buff
*skb
,
1131 struct flow_dissector
*flow_dissector
,
1132 void *target_container
, unsigned int flags
)
1134 return __skb_flow_dissect(skb
, flow_dissector
, target_container
,
1135 NULL
, 0, 0, 0, flags
);
1138 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff
*skb
,
1139 struct flow_keys
*flow
,
1142 memset(flow
, 0, sizeof(*flow
));
1143 return __skb_flow_dissect(skb
, &flow_keys_dissector
, flow
,
1144 NULL
, 0, 0, 0, flags
);
1147 static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys
*flow
,
1148 void *data
, __be16 proto
,
1149 int nhoff
, int hlen
,
1152 memset(flow
, 0, sizeof(*flow
));
1153 return __skb_flow_dissect(NULL
, &flow_keys_buf_dissector
, flow
,
1154 data
, proto
, nhoff
, hlen
, flags
);
1157 static inline __u32
skb_get_hash(struct sk_buff
*skb
)
1159 if (!skb
->l4_hash
&& !skb
->sw_hash
)
1160 __skb_get_hash(skb
);
1165 __u32
__skb_get_hash_flowi6(struct sk_buff
*skb
, const struct flowi6
*fl6
);
1167 static inline __u32
skb_get_hash_flowi6(struct sk_buff
*skb
, const struct flowi6
*fl6
)
1169 if (!skb
->l4_hash
&& !skb
->sw_hash
) {
1170 struct flow_keys keys
;
1171 __u32 hash
= __get_hash_from_flowi6(fl6
, &keys
);
1173 __skb_set_sw_hash(skb
, hash
, flow_keys_have_l4(&keys
));
1179 __u32
__skb_get_hash_flowi4(struct sk_buff
*skb
, const struct flowi4
*fl
);
1181 static inline __u32
skb_get_hash_flowi4(struct sk_buff
*skb
, const struct flowi4
*fl4
)
1183 if (!skb
->l4_hash
&& !skb
->sw_hash
) {
1184 struct flow_keys keys
;
1185 __u32 hash
= __get_hash_from_flowi4(fl4
, &keys
);
1187 __skb_set_sw_hash(skb
, hash
, flow_keys_have_l4(&keys
));
1193 __u32
skb_get_hash_perturb(const struct sk_buff
*skb
, u32 perturb
);
1195 static inline __u32
skb_get_hash_raw(const struct sk_buff
*skb
)
1200 static inline void skb_copy_hash(struct sk_buff
*to
, const struct sk_buff
*from
)
1202 to
->hash
= from
->hash
;
1203 to
->sw_hash
= from
->sw_hash
;
1204 to
->l4_hash
= from
->l4_hash
;
1207 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1208 static inline unsigned char *skb_end_pointer(const struct sk_buff
*skb
)
1210 return skb
->head
+ skb
->end
;
1213 static inline unsigned int skb_end_offset(const struct sk_buff
*skb
)
1218 static inline unsigned char *skb_end_pointer(const struct sk_buff
*skb
)
1223 static inline unsigned int skb_end_offset(const struct sk_buff
*skb
)
1225 return skb
->end
- skb
->head
;
1230 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1232 static inline struct skb_shared_hwtstamps
*skb_hwtstamps(struct sk_buff
*skb
)
1234 return &skb_shinfo(skb
)->hwtstamps
;
1238 * skb_queue_empty - check if a queue is empty
1241 * Returns true if the queue is empty, false otherwise.
1243 static inline int skb_queue_empty(const struct sk_buff_head
*list
)
1245 return list
->next
== (const struct sk_buff
*) list
;
1249 * skb_queue_is_last - check if skb is the last entry in the queue
1253 * Returns true if @skb is the last buffer on the list.
1255 static inline bool skb_queue_is_last(const struct sk_buff_head
*list
,
1256 const struct sk_buff
*skb
)
1258 return skb
->next
== (const struct sk_buff
*) list
;
1262 * skb_queue_is_first - check if skb is the first entry in the queue
1266 * Returns true if @skb is the first buffer on the list.
1268 static inline bool skb_queue_is_first(const struct sk_buff_head
*list
,
1269 const struct sk_buff
*skb
)
1271 return skb
->prev
== (const struct sk_buff
*) list
;
1275 * skb_queue_next - return the next packet in the queue
1277 * @skb: current buffer
1279 * Return the next packet in @list after @skb. It is only valid to
1280 * call this if skb_queue_is_last() evaluates to false.
1282 static inline struct sk_buff
*skb_queue_next(const struct sk_buff_head
*list
,
1283 const struct sk_buff
*skb
)
1285 /* This BUG_ON may seem severe, but if we just return then we
1286 * are going to dereference garbage.
1288 BUG_ON(skb_queue_is_last(list
, skb
));
1293 * skb_queue_prev - return the prev packet in the queue
1295 * @skb: current buffer
1297 * Return the prev packet in @list before @skb. It is only valid to
1298 * call this if skb_queue_is_first() evaluates to false.
1300 static inline struct sk_buff
*skb_queue_prev(const struct sk_buff_head
*list
,
1301 const struct sk_buff
*skb
)
1303 /* This BUG_ON may seem severe, but if we just return then we
1304 * are going to dereference garbage.
1306 BUG_ON(skb_queue_is_first(list
, skb
));
1311 * skb_get - reference buffer
1312 * @skb: buffer to reference
1314 * Makes another reference to a socket buffer and returns a pointer
1317 static inline struct sk_buff
*skb_get(struct sk_buff
*skb
)
1319 atomic_inc(&skb
->users
);
1324 * If users == 1, we are the only owner and are can avoid redundant
1329 * skb_cloned - is the buffer a clone
1330 * @skb: buffer to check
1332 * Returns true if the buffer was generated with skb_clone() and is
1333 * one of multiple shared copies of the buffer. Cloned buffers are
1334 * shared data so must not be written to under normal circumstances.
1336 static inline int skb_cloned(const struct sk_buff
*skb
)
1338 return skb
->cloned
&&
1339 (atomic_read(&skb_shinfo(skb
)->dataref
) & SKB_DATAREF_MASK
) != 1;
1342 static inline int skb_unclone(struct sk_buff
*skb
, gfp_t pri
)
1344 might_sleep_if(gfpflags_allow_blocking(pri
));
1346 if (skb_cloned(skb
))
1347 return pskb_expand_head(skb
, 0, 0, pri
);
1353 * skb_header_cloned - is the header a clone
1354 * @skb: buffer to check
1356 * Returns true if modifying the header part of the buffer requires
1357 * the data to be copied.
1359 static inline int skb_header_cloned(const struct sk_buff
*skb
)
1366 dataref
= atomic_read(&skb_shinfo(skb
)->dataref
);
1367 dataref
= (dataref
& SKB_DATAREF_MASK
) - (dataref
>> SKB_DATAREF_SHIFT
);
1368 return dataref
!= 1;
1371 static inline int skb_header_unclone(struct sk_buff
*skb
, gfp_t pri
)
1373 might_sleep_if(gfpflags_allow_blocking(pri
));
1375 if (skb_header_cloned(skb
))
1376 return pskb_expand_head(skb
, 0, 0, pri
);
1382 * skb_header_release - release reference to header
1383 * @skb: buffer to operate on
1385 * Drop a reference to the header part of the buffer. This is done
1386 * by acquiring a payload reference. You must not read from the header
1387 * part of skb->data after this.
1388 * Note : Check if you can use __skb_header_release() instead.
1390 static inline void skb_header_release(struct sk_buff
*skb
)
1394 atomic_add(1 << SKB_DATAREF_SHIFT
, &skb_shinfo(skb
)->dataref
);
1398 * __skb_header_release - release reference to header
1399 * @skb: buffer to operate on
1401 * Variant of skb_header_release() assuming skb is private to caller.
1402 * We can avoid one atomic operation.
1404 static inline void __skb_header_release(struct sk_buff
*skb
)
1407 atomic_set(&skb_shinfo(skb
)->dataref
, 1 + (1 << SKB_DATAREF_SHIFT
));
1412 * skb_shared - is the buffer shared
1413 * @skb: buffer to check
1415 * Returns true if more than one person has a reference to this
1418 static inline int skb_shared(const struct sk_buff
*skb
)
1420 return atomic_read(&skb
->users
) != 1;
1424 * skb_share_check - check if buffer is shared and if so clone it
1425 * @skb: buffer to check
1426 * @pri: priority for memory allocation
1428 * If the buffer is shared the buffer is cloned and the old copy
1429 * drops a reference. A new clone with a single reference is returned.
1430 * If the buffer is not shared the original buffer is returned. When
1431 * being called from interrupt status or with spinlocks held pri must
1434 * NULL is returned on a memory allocation failure.
1436 static inline struct sk_buff
*skb_share_check(struct sk_buff
*skb
, gfp_t pri
)
1438 might_sleep_if(gfpflags_allow_blocking(pri
));
1439 if (skb_shared(skb
)) {
1440 struct sk_buff
*nskb
= skb_clone(skb
, pri
);
1452 * Copy shared buffers into a new sk_buff. We effectively do COW on
1453 * packets to handle cases where we have a local reader and forward
1454 * and a couple of other messy ones. The normal one is tcpdumping
1455 * a packet thats being forwarded.
1459 * skb_unshare - make a copy of a shared buffer
1460 * @skb: buffer to check
1461 * @pri: priority for memory allocation
1463 * If the socket buffer is a clone then this function creates a new
1464 * copy of the data, drops a reference count on the old copy and returns
1465 * the new copy with the reference count at 1. If the buffer is not a clone
1466 * the original buffer is returned. When called with a spinlock held or
1467 * from interrupt state @pri must be %GFP_ATOMIC
1469 * %NULL is returned on a memory allocation failure.
1471 static inline struct sk_buff
*skb_unshare(struct sk_buff
*skb
,
1474 might_sleep_if(gfpflags_allow_blocking(pri
));
1475 if (skb_cloned(skb
)) {
1476 struct sk_buff
*nskb
= skb_copy(skb
, pri
);
1478 /* Free our shared copy */
1489 * skb_peek - peek at the head of an &sk_buff_head
1490 * @list_: list to peek at
1492 * Peek an &sk_buff. Unlike most other operations you _MUST_
1493 * be careful with this one. A peek leaves the buffer on the
1494 * list and someone else may run off with it. You must hold
1495 * the appropriate locks or have a private queue to do this.
1497 * Returns %NULL for an empty list or a pointer to the head element.
1498 * The reference count is not incremented and the reference is therefore
1499 * volatile. Use with caution.
1501 static inline struct sk_buff
*skb_peek(const struct sk_buff_head
*list_
)
1503 struct sk_buff
*skb
= list_
->next
;
1505 if (skb
== (struct sk_buff
*)list_
)
1511 * skb_peek_next - peek skb following the given one from a queue
1512 * @skb: skb to start from
1513 * @list_: list to peek at
1515 * Returns %NULL when the end of the list is met or a pointer to the
1516 * next element. The reference count is not incremented and the
1517 * reference is therefore volatile. Use with caution.
1519 static inline struct sk_buff
*skb_peek_next(struct sk_buff
*skb
,
1520 const struct sk_buff_head
*list_
)
1522 struct sk_buff
*next
= skb
->next
;
1524 if (next
== (struct sk_buff
*)list_
)
1530 * skb_peek_tail - peek at the tail of an &sk_buff_head
1531 * @list_: list to peek at
1533 * Peek an &sk_buff. Unlike most other operations you _MUST_
1534 * be careful with this one. A peek leaves the buffer on the
1535 * list and someone else may run off with it. You must hold
1536 * the appropriate locks or have a private queue to do this.
1538 * Returns %NULL for an empty list or a pointer to the tail element.
1539 * The reference count is not incremented and the reference is therefore
1540 * volatile. Use with caution.
1542 static inline struct sk_buff
*skb_peek_tail(const struct sk_buff_head
*list_
)
1544 struct sk_buff
*skb
= list_
->prev
;
1546 if (skb
== (struct sk_buff
*)list_
)
1553 * skb_queue_len - get queue length
1554 * @list_: list to measure
1556 * Return the length of an &sk_buff queue.
1558 static inline __u32
skb_queue_len(const struct sk_buff_head
*list_
)
1564 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1565 * @list: queue to initialize
1567 * This initializes only the list and queue length aspects of
1568 * an sk_buff_head object. This allows to initialize the list
1569 * aspects of an sk_buff_head without reinitializing things like
1570 * the spinlock. It can also be used for on-stack sk_buff_head
1571 * objects where the spinlock is known to not be used.
1573 static inline void __skb_queue_head_init(struct sk_buff_head
*list
)
1575 list
->prev
= list
->next
= (struct sk_buff
*)list
;
1580 * This function creates a split out lock class for each invocation;
1581 * this is needed for now since a whole lot of users of the skb-queue
1582 * infrastructure in drivers have different locking usage (in hardirq)
1583 * than the networking core (in softirq only). In the long run either the
1584 * network layer or drivers should need annotation to consolidate the
1585 * main types of usage into 3 classes.
1587 static inline void skb_queue_head_init(struct sk_buff_head
*list
)
1589 spin_lock_init(&list
->lock
);
1590 __skb_queue_head_init(list
);
1593 static inline void skb_queue_head_init_class(struct sk_buff_head
*list
,
1594 struct lock_class_key
*class)
1596 skb_queue_head_init(list
);
1597 lockdep_set_class(&list
->lock
, class);
1601 * Insert an sk_buff on a list.
1603 * The "__skb_xxxx()" functions are the non-atomic ones that
1604 * can only be called with interrupts disabled.
1606 void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
,
1607 struct sk_buff_head
*list
);
1608 static inline void __skb_insert(struct sk_buff
*newsk
,
1609 struct sk_buff
*prev
, struct sk_buff
*next
,
1610 struct sk_buff_head
*list
)
1614 next
->prev
= prev
->next
= newsk
;
1618 static inline void __skb_queue_splice(const struct sk_buff_head
*list
,
1619 struct sk_buff
*prev
,
1620 struct sk_buff
*next
)
1622 struct sk_buff
*first
= list
->next
;
1623 struct sk_buff
*last
= list
->prev
;
1633 * skb_queue_splice - join two skb lists, this is designed for stacks
1634 * @list: the new list to add
1635 * @head: the place to add it in the first list
1637 static inline void skb_queue_splice(const struct sk_buff_head
*list
,
1638 struct sk_buff_head
*head
)
1640 if (!skb_queue_empty(list
)) {
1641 __skb_queue_splice(list
, (struct sk_buff
*) head
, head
->next
);
1642 head
->qlen
+= list
->qlen
;
1647 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1648 * @list: the new list to add
1649 * @head: the place to add it in the first list
1651 * The list at @list is reinitialised
1653 static inline void skb_queue_splice_init(struct sk_buff_head
*list
,
1654 struct sk_buff_head
*head
)
1656 if (!skb_queue_empty(list
)) {
1657 __skb_queue_splice(list
, (struct sk_buff
*) head
, head
->next
);
1658 head
->qlen
+= list
->qlen
;
1659 __skb_queue_head_init(list
);
1664 * skb_queue_splice_tail - join two skb lists, each list being a queue
1665 * @list: the new list to add
1666 * @head: the place to add it in the first list
1668 static inline void skb_queue_splice_tail(const struct sk_buff_head
*list
,
1669 struct sk_buff_head
*head
)
1671 if (!skb_queue_empty(list
)) {
1672 __skb_queue_splice(list
, head
->prev
, (struct sk_buff
*) head
);
1673 head
->qlen
+= list
->qlen
;
1678 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1679 * @list: the new list to add
1680 * @head: the place to add it in the first list
1682 * Each of the lists is a queue.
1683 * The list at @list is reinitialised
1685 static inline void skb_queue_splice_tail_init(struct sk_buff_head
*list
,
1686 struct sk_buff_head
*head
)
1688 if (!skb_queue_empty(list
)) {
1689 __skb_queue_splice(list
, head
->prev
, (struct sk_buff
*) head
);
1690 head
->qlen
+= list
->qlen
;
1691 __skb_queue_head_init(list
);
1696 * __skb_queue_after - queue a buffer at the list head
1697 * @list: list to use
1698 * @prev: place after this buffer
1699 * @newsk: buffer to queue
1701 * Queue a buffer int the middle of a list. This function takes no locks
1702 * and you must therefore hold required locks before calling it.
1704 * A buffer cannot be placed on two lists at the same time.
1706 static inline void __skb_queue_after(struct sk_buff_head
*list
,
1707 struct sk_buff
*prev
,
1708 struct sk_buff
*newsk
)
1710 __skb_insert(newsk
, prev
, prev
->next
, list
);
1713 void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
,
1714 struct sk_buff_head
*list
);
1716 static inline void __skb_queue_before(struct sk_buff_head
*list
,
1717 struct sk_buff
*next
,
1718 struct sk_buff
*newsk
)
1720 __skb_insert(newsk
, next
->prev
, next
, list
);
1724 * __skb_queue_head - queue a buffer at the list head
1725 * @list: list to use
1726 * @newsk: buffer to queue
1728 * Queue a buffer at the start of a list. This function takes no locks
1729 * and you must therefore hold required locks before calling it.
1731 * A buffer cannot be placed on two lists at the same time.
1733 void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
);
1734 static inline void __skb_queue_head(struct sk_buff_head
*list
,
1735 struct sk_buff
*newsk
)
1737 __skb_queue_after(list
, (struct sk_buff
*)list
, newsk
);
1741 * __skb_queue_tail - queue a buffer at the list tail
1742 * @list: list to use
1743 * @newsk: buffer to queue
1745 * Queue a buffer at the end of a list. This function takes no locks
1746 * and you must therefore hold required locks before calling it.
1748 * A buffer cannot be placed on two lists at the same time.
1750 void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
);
1751 static inline void __skb_queue_tail(struct sk_buff_head
*list
,
1752 struct sk_buff
*newsk
)
1754 __skb_queue_before(list
, (struct sk_buff
*)list
, newsk
);
1758 * remove sk_buff from list. _Must_ be called atomically, and with
1761 void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
);
1762 static inline void __skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
1764 struct sk_buff
*next
, *prev
;
1769 skb
->next
= skb
->prev
= NULL
;
1775 * __skb_dequeue - remove from the head of the queue
1776 * @list: list to dequeue from
1778 * Remove the head of the list. This function does not take any locks
1779 * so must be used with appropriate locks held only. The head item is
1780 * returned or %NULL if the list is empty.
1782 struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
);
1783 static inline struct sk_buff
*__skb_dequeue(struct sk_buff_head
*list
)
1785 struct sk_buff
*skb
= skb_peek(list
);
1787 __skb_unlink(skb
, list
);
1792 * __skb_dequeue_tail - remove from the tail of the queue
1793 * @list: list to dequeue from
1795 * Remove the tail of the list. This function does not take any locks
1796 * so must be used with appropriate locks held only. The tail item is
1797 * returned or %NULL if the list is empty.
1799 struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
);
1800 static inline struct sk_buff
*__skb_dequeue_tail(struct sk_buff_head
*list
)
1802 struct sk_buff
*skb
= skb_peek_tail(list
);
1804 __skb_unlink(skb
, list
);
1809 static inline bool skb_is_nonlinear(const struct sk_buff
*skb
)
1811 return skb
->data_len
;
1814 static inline unsigned int skb_headlen(const struct sk_buff
*skb
)
1816 return skb
->len
- skb
->data_len
;
1819 static inline unsigned int skb_pagelen(const struct sk_buff
*skb
)
1821 unsigned int i
, len
= 0;
1823 for (i
= skb_shinfo(skb
)->nr_frags
- 1; (int)i
>= 0; i
--)
1824 len
+= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1825 return len
+ skb_headlen(skb
);
1829 * __skb_fill_page_desc - initialise a paged fragment in an skb
1830 * @skb: buffer containing fragment to be initialised
1831 * @i: paged fragment index to initialise
1832 * @page: the page to use for this fragment
1833 * @off: the offset to the data with @page
1834 * @size: the length of the data
1836 * Initialises the @i'th fragment of @skb to point to &size bytes at
1837 * offset @off within @page.
1839 * Does not take any additional reference on the fragment.
1841 static inline void __skb_fill_page_desc(struct sk_buff
*skb
, int i
,
1842 struct page
*page
, int off
, int size
)
1844 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1847 * Propagate page pfmemalloc to the skb if we can. The problem is
1848 * that not all callers have unique ownership of the page but rely
1849 * on page_is_pfmemalloc doing the right thing(tm).
1851 frag
->page
.p
= page
;
1852 frag
->page_offset
= off
;
1853 skb_frag_size_set(frag
, size
);
1855 page
= compound_head(page
);
1856 if (page_is_pfmemalloc(page
))
1857 skb
->pfmemalloc
= true;
1861 * skb_fill_page_desc - initialise a paged fragment in an skb
1862 * @skb: buffer containing fragment to be initialised
1863 * @i: paged fragment index to initialise
1864 * @page: the page to use for this fragment
1865 * @off: the offset to the data with @page
1866 * @size: the length of the data
1868 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1869 * @skb to point to @size bytes at offset @off within @page. In
1870 * addition updates @skb such that @i is the last fragment.
1872 * Does not take any additional reference on the fragment.
1874 static inline void skb_fill_page_desc(struct sk_buff
*skb
, int i
,
1875 struct page
*page
, int off
, int size
)
1877 __skb_fill_page_desc(skb
, i
, page
, off
, size
);
1878 skb_shinfo(skb
)->nr_frags
= i
+ 1;
1881 void skb_add_rx_frag(struct sk_buff
*skb
, int i
, struct page
*page
, int off
,
1882 int size
, unsigned int truesize
);
1884 void skb_coalesce_rx_frag(struct sk_buff
*skb
, int i
, int size
,
1885 unsigned int truesize
);
1887 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1888 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1889 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1891 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1892 static inline unsigned char *skb_tail_pointer(const struct sk_buff
*skb
)
1894 return skb
->head
+ skb
->tail
;
1897 static inline void skb_reset_tail_pointer(struct sk_buff
*skb
)
1899 skb
->tail
= skb
->data
- skb
->head
;
1902 static inline void skb_set_tail_pointer(struct sk_buff
*skb
, const int offset
)
1904 skb_reset_tail_pointer(skb
);
1905 skb
->tail
+= offset
;
1908 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1909 static inline unsigned char *skb_tail_pointer(const struct sk_buff
*skb
)
1914 static inline void skb_reset_tail_pointer(struct sk_buff
*skb
)
1916 skb
->tail
= skb
->data
;
1919 static inline void skb_set_tail_pointer(struct sk_buff
*skb
, const int offset
)
1921 skb
->tail
= skb
->data
+ offset
;
1924 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1927 * Add data to an sk_buff
1929 unsigned char *pskb_put(struct sk_buff
*skb
, struct sk_buff
*tail
, int len
);
1930 unsigned char *skb_put(struct sk_buff
*skb
, unsigned int len
);
1931 static inline unsigned char *__skb_put(struct sk_buff
*skb
, unsigned int len
)
1933 unsigned char *tmp
= skb_tail_pointer(skb
);
1934 SKB_LINEAR_ASSERT(skb
);
1940 unsigned char *skb_push(struct sk_buff
*skb
, unsigned int len
);
1941 static inline unsigned char *__skb_push(struct sk_buff
*skb
, unsigned int len
)
1948 unsigned char *skb_pull(struct sk_buff
*skb
, unsigned int len
);
1949 static inline unsigned char *__skb_pull(struct sk_buff
*skb
, unsigned int len
)
1952 BUG_ON(skb
->len
< skb
->data_len
);
1953 return skb
->data
+= len
;
1956 static inline unsigned char *skb_pull_inline(struct sk_buff
*skb
, unsigned int len
)
1958 return unlikely(len
> skb
->len
) ? NULL
: __skb_pull(skb
, len
);
1961 unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
);
1963 static inline unsigned char *__pskb_pull(struct sk_buff
*skb
, unsigned int len
)
1965 if (len
> skb_headlen(skb
) &&
1966 !__pskb_pull_tail(skb
, len
- skb_headlen(skb
)))
1969 return skb
->data
+= len
;
1972 static inline unsigned char *pskb_pull(struct sk_buff
*skb
, unsigned int len
)
1974 return unlikely(len
> skb
->len
) ? NULL
: __pskb_pull(skb
, len
);
1977 static inline int pskb_may_pull(struct sk_buff
*skb
, unsigned int len
)
1979 if (likely(len
<= skb_headlen(skb
)))
1981 if (unlikely(len
> skb
->len
))
1983 return __pskb_pull_tail(skb
, len
- skb_headlen(skb
)) != NULL
;
1986 void skb_condense(struct sk_buff
*skb
);
1989 * skb_headroom - bytes at buffer head
1990 * @skb: buffer to check
1992 * Return the number of bytes of free space at the head of an &sk_buff.
1994 static inline unsigned int skb_headroom(const struct sk_buff
*skb
)
1996 return skb
->data
- skb
->head
;
2000 * skb_tailroom - bytes at buffer end
2001 * @skb: buffer to check
2003 * Return the number of bytes of free space at the tail of an sk_buff
2005 static inline int skb_tailroom(const struct sk_buff
*skb
)
2007 return skb_is_nonlinear(skb
) ? 0 : skb
->end
- skb
->tail
;
2011 * skb_availroom - bytes at buffer end
2012 * @skb: buffer to check
2014 * Return the number of bytes of free space at the tail of an sk_buff
2015 * allocated by sk_stream_alloc()
2017 static inline int skb_availroom(const struct sk_buff
*skb
)
2019 if (skb_is_nonlinear(skb
))
2022 return skb
->end
- skb
->tail
- skb
->reserved_tailroom
;
2026 * skb_reserve - adjust headroom
2027 * @skb: buffer to alter
2028 * @len: bytes to move
2030 * Increase the headroom of an empty &sk_buff by reducing the tail
2031 * room. This is only allowed for an empty buffer.
2033 static inline void skb_reserve(struct sk_buff
*skb
, int len
)
2040 * skb_tailroom_reserve - adjust reserved_tailroom
2041 * @skb: buffer to alter
2042 * @mtu: maximum amount of headlen permitted
2043 * @needed_tailroom: minimum amount of reserved_tailroom
2045 * Set reserved_tailroom so that headlen can be as large as possible but
2046 * not larger than mtu and tailroom cannot be smaller than
2048 * The required headroom should already have been reserved before using
2051 static inline void skb_tailroom_reserve(struct sk_buff
*skb
, unsigned int mtu
,
2052 unsigned int needed_tailroom
)
2054 SKB_LINEAR_ASSERT(skb
);
2055 if (mtu
< skb_tailroom(skb
) - needed_tailroom
)
2056 /* use at most mtu */
2057 skb
->reserved_tailroom
= skb_tailroom(skb
) - mtu
;
2059 /* use up to all available space */
2060 skb
->reserved_tailroom
= needed_tailroom
;
2063 #define ENCAP_TYPE_ETHER 0
2064 #define ENCAP_TYPE_IPPROTO 1
2066 static inline void skb_set_inner_protocol(struct sk_buff
*skb
,
2069 skb
->inner_protocol
= protocol
;
2070 skb
->inner_protocol_type
= ENCAP_TYPE_ETHER
;
2073 static inline void skb_set_inner_ipproto(struct sk_buff
*skb
,
2076 skb
->inner_ipproto
= ipproto
;
2077 skb
->inner_protocol_type
= ENCAP_TYPE_IPPROTO
;
2080 static inline void skb_reset_inner_headers(struct sk_buff
*skb
)
2082 skb
->inner_mac_header
= skb
->mac_header
;
2083 skb
->inner_network_header
= skb
->network_header
;
2084 skb
->inner_transport_header
= skb
->transport_header
;
2087 static inline void skb_reset_mac_len(struct sk_buff
*skb
)
2089 skb
->mac_len
= skb
->network_header
- skb
->mac_header
;
2092 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2095 return skb
->head
+ skb
->inner_transport_header
;
2098 static inline int skb_inner_transport_offset(const struct sk_buff
*skb
)
2100 return skb_inner_transport_header(skb
) - skb
->data
;
2103 static inline void skb_reset_inner_transport_header(struct sk_buff
*skb
)
2105 skb
->inner_transport_header
= skb
->data
- skb
->head
;
2108 static inline void skb_set_inner_transport_header(struct sk_buff
*skb
,
2111 skb_reset_inner_transport_header(skb
);
2112 skb
->inner_transport_header
+= offset
;
2115 static inline unsigned char *skb_inner_network_header(const struct sk_buff
*skb
)
2117 return skb
->head
+ skb
->inner_network_header
;
2120 static inline void skb_reset_inner_network_header(struct sk_buff
*skb
)
2122 skb
->inner_network_header
= skb
->data
- skb
->head
;
2125 static inline void skb_set_inner_network_header(struct sk_buff
*skb
,
2128 skb_reset_inner_network_header(skb
);
2129 skb
->inner_network_header
+= offset
;
2132 static inline unsigned char *skb_inner_mac_header(const struct sk_buff
*skb
)
2134 return skb
->head
+ skb
->inner_mac_header
;
2137 static inline void skb_reset_inner_mac_header(struct sk_buff
*skb
)
2139 skb
->inner_mac_header
= skb
->data
- skb
->head
;
2142 static inline void skb_set_inner_mac_header(struct sk_buff
*skb
,
2145 skb_reset_inner_mac_header(skb
);
2146 skb
->inner_mac_header
+= offset
;
2148 static inline bool skb_transport_header_was_set(const struct sk_buff
*skb
)
2150 return skb
->transport_header
!= (typeof(skb
->transport_header
))~0U;
2153 static inline unsigned char *skb_transport_header(const struct sk_buff
*skb
)
2155 return skb
->head
+ skb
->transport_header
;
2158 static inline void skb_reset_transport_header(struct sk_buff
*skb
)
2160 skb
->transport_header
= skb
->data
- skb
->head
;
2163 static inline void skb_set_transport_header(struct sk_buff
*skb
,
2166 skb_reset_transport_header(skb
);
2167 skb
->transport_header
+= offset
;
2170 static inline unsigned char *skb_network_header(const struct sk_buff
*skb
)
2172 return skb
->head
+ skb
->network_header
;
2175 static inline void skb_reset_network_header(struct sk_buff
*skb
)
2177 skb
->network_header
= skb
->data
- skb
->head
;
2180 static inline void skb_set_network_header(struct sk_buff
*skb
, const int offset
)
2182 skb_reset_network_header(skb
);
2183 skb
->network_header
+= offset
;
2186 static inline unsigned char *skb_mac_header(const struct sk_buff
*skb
)
2188 return skb
->head
+ skb
->mac_header
;
2191 static inline int skb_mac_offset(const struct sk_buff
*skb
)
2193 return skb_mac_header(skb
) - skb
->data
;
2196 static inline int skb_mac_header_was_set(const struct sk_buff
*skb
)
2198 return skb
->mac_header
!= (typeof(skb
->mac_header
))~0U;
2201 static inline void skb_reset_mac_header(struct sk_buff
*skb
)
2203 skb
->mac_header
= skb
->data
- skb
->head
;
2206 static inline void skb_set_mac_header(struct sk_buff
*skb
, const int offset
)
2208 skb_reset_mac_header(skb
);
2209 skb
->mac_header
+= offset
;
2212 static inline void skb_pop_mac_header(struct sk_buff
*skb
)
2214 skb
->mac_header
= skb
->network_header
;
2217 static inline void skb_probe_transport_header(struct sk_buff
*skb
,
2218 const int offset_hint
)
2220 struct flow_keys keys
;
2222 if (skb_transport_header_was_set(skb
))
2224 else if (skb_flow_dissect_flow_keys(skb
, &keys
, 0))
2225 skb_set_transport_header(skb
, keys
.control
.thoff
);
2227 skb_set_transport_header(skb
, offset_hint
);
2230 static inline void skb_mac_header_rebuild(struct sk_buff
*skb
)
2232 if (skb_mac_header_was_set(skb
)) {
2233 const unsigned char *old_mac
= skb_mac_header(skb
);
2235 skb_set_mac_header(skb
, -skb
->mac_len
);
2236 memmove(skb_mac_header(skb
), old_mac
, skb
->mac_len
);
2240 static inline int skb_checksum_start_offset(const struct sk_buff
*skb
)
2242 return skb
->csum_start
- skb_headroom(skb
);
2245 static inline unsigned char *skb_checksum_start(const struct sk_buff
*skb
)
2247 return skb
->head
+ skb
->csum_start
;
2250 static inline int skb_transport_offset(const struct sk_buff
*skb
)
2252 return skb_transport_header(skb
) - skb
->data
;
2255 static inline u32
skb_network_header_len(const struct sk_buff
*skb
)
2257 return skb
->transport_header
- skb
->network_header
;
2260 static inline u32
skb_inner_network_header_len(const struct sk_buff
*skb
)
2262 return skb
->inner_transport_header
- skb
->inner_network_header
;
2265 static inline int skb_network_offset(const struct sk_buff
*skb
)
2267 return skb_network_header(skb
) - skb
->data
;
2270 static inline int skb_inner_network_offset(const struct sk_buff
*skb
)
2272 return skb_inner_network_header(skb
) - skb
->data
;
2275 static inline int pskb_network_may_pull(struct sk_buff
*skb
, unsigned int len
)
2277 return pskb_may_pull(skb
, skb_network_offset(skb
) + len
);
2281 * CPUs often take a performance hit when accessing unaligned memory
2282 * locations. The actual performance hit varies, it can be small if the
2283 * hardware handles it or large if we have to take an exception and fix it
2286 * Since an ethernet header is 14 bytes network drivers often end up with
2287 * the IP header at an unaligned offset. The IP header can be aligned by
2288 * shifting the start of the packet by 2 bytes. Drivers should do this
2291 * skb_reserve(skb, NET_IP_ALIGN);
2293 * The downside to this alignment of the IP header is that the DMA is now
2294 * unaligned. On some architectures the cost of an unaligned DMA is high
2295 * and this cost outweighs the gains made by aligning the IP header.
2297 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2300 #ifndef NET_IP_ALIGN
2301 #define NET_IP_ALIGN 2
2305 * The networking layer reserves some headroom in skb data (via
2306 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2307 * the header has to grow. In the default case, if the header has to grow
2308 * 32 bytes or less we avoid the reallocation.
2310 * Unfortunately this headroom changes the DMA alignment of the resulting
2311 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2312 * on some architectures. An architecture can override this value,
2313 * perhaps setting it to a cacheline in size (since that will maintain
2314 * cacheline alignment of the DMA). It must be a power of 2.
2316 * Various parts of the networking layer expect at least 32 bytes of
2317 * headroom, you should not reduce this.
2319 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2320 * to reduce average number of cache lines per packet.
2321 * get_rps_cpus() for example only access one 64 bytes aligned block :
2322 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2325 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
2328 int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
);
2330 static inline void __skb_set_length(struct sk_buff
*skb
, unsigned int len
)
2332 if (unlikely(skb_is_nonlinear(skb
))) {
2337 skb_set_tail_pointer(skb
, len
);
2340 static inline void __skb_trim(struct sk_buff
*skb
, unsigned int len
)
2342 __skb_set_length(skb
, len
);
2345 void skb_trim(struct sk_buff
*skb
, unsigned int len
);
2347 static inline int __pskb_trim(struct sk_buff
*skb
, unsigned int len
)
2350 return ___pskb_trim(skb
, len
);
2351 __skb_trim(skb
, len
);
2355 static inline int pskb_trim(struct sk_buff
*skb
, unsigned int len
)
2357 return (len
< skb
->len
) ? __pskb_trim(skb
, len
) : 0;
2361 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2362 * @skb: buffer to alter
2365 * This is identical to pskb_trim except that the caller knows that
2366 * the skb is not cloned so we should never get an error due to out-
2369 static inline void pskb_trim_unique(struct sk_buff
*skb
, unsigned int len
)
2371 int err
= pskb_trim(skb
, len
);
2375 static inline int __skb_grow(struct sk_buff
*skb
, unsigned int len
)
2377 unsigned int diff
= len
- skb
->len
;
2379 if (skb_tailroom(skb
) < diff
) {
2380 int ret
= pskb_expand_head(skb
, 0, diff
- skb_tailroom(skb
),
2385 __skb_set_length(skb
, len
);
2390 * skb_orphan - orphan a buffer
2391 * @skb: buffer to orphan
2393 * If a buffer currently has an owner then we call the owner's
2394 * destructor function and make the @skb unowned. The buffer continues
2395 * to exist but is no longer charged to its former owner.
2397 static inline void skb_orphan(struct sk_buff
*skb
)
2399 if (skb
->destructor
) {
2400 skb
->destructor(skb
);
2401 skb
->destructor
= NULL
;
2409 * skb_orphan_frags - orphan the frags contained in a buffer
2410 * @skb: buffer to orphan frags from
2411 * @gfp_mask: allocation mask for replacement pages
2413 * For each frag in the SKB which needs a destructor (i.e. has an
2414 * owner) create a copy of that frag and release the original
2415 * page by calling the destructor.
2417 static inline int skb_orphan_frags(struct sk_buff
*skb
, gfp_t gfp_mask
)
2419 if (likely(!(skb_shinfo(skb
)->tx_flags
& SKBTX_DEV_ZEROCOPY
)))
2421 return skb_copy_ubufs(skb
, gfp_mask
);
2425 * __skb_queue_purge - empty a list
2426 * @list: list to empty
2428 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2429 * the list and one reference dropped. This function does not take the
2430 * list lock and the caller must hold the relevant locks to use it.
2432 void skb_queue_purge(struct sk_buff_head
*list
);
2433 static inline void __skb_queue_purge(struct sk_buff_head
*list
)
2435 struct sk_buff
*skb
;
2436 while ((skb
= __skb_dequeue(list
)) != NULL
)
2440 void skb_rbtree_purge(struct rb_root
*root
);
2442 void *netdev_alloc_frag(unsigned int fragsz
);
2444 struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
, unsigned int length
,
2448 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
2449 * @dev: network device to receive on
2450 * @length: length to allocate
2452 * Allocate a new &sk_buff and assign it a usage count of one. The
2453 * buffer has unspecified headroom built in. Users should allocate
2454 * the headroom they think they need without accounting for the
2455 * built in space. The built in space is used for optimisations.
2457 * %NULL is returned if there is no free memory. Although this function
2458 * allocates memory it can be called from an interrupt.
2460 static inline struct sk_buff
*netdev_alloc_skb(struct net_device
*dev
,
2461 unsigned int length
)
2463 return __netdev_alloc_skb(dev
, length
, GFP_ATOMIC
);
2466 /* legacy helper around __netdev_alloc_skb() */
2467 static inline struct sk_buff
*__dev_alloc_skb(unsigned int length
,
2470 return __netdev_alloc_skb(NULL
, length
, gfp_mask
);
2473 /* legacy helper around netdev_alloc_skb() */
2474 static inline struct sk_buff
*dev_alloc_skb(unsigned int length
)
2476 return netdev_alloc_skb(NULL
, length
);
2480 static inline struct sk_buff
*__netdev_alloc_skb_ip_align(struct net_device
*dev
,
2481 unsigned int length
, gfp_t gfp
)
2483 struct sk_buff
*skb
= __netdev_alloc_skb(dev
, length
+ NET_IP_ALIGN
, gfp
);
2485 if (NET_IP_ALIGN
&& skb
)
2486 skb_reserve(skb
, NET_IP_ALIGN
);
2490 static inline struct sk_buff
*netdev_alloc_skb_ip_align(struct net_device
*dev
,
2491 unsigned int length
)
2493 return __netdev_alloc_skb_ip_align(dev
, length
, GFP_ATOMIC
);
2496 static inline void skb_free_frag(void *addr
)
2498 page_frag_free(addr
);
2501 void *napi_alloc_frag(unsigned int fragsz
);
2502 struct sk_buff
*__napi_alloc_skb(struct napi_struct
*napi
,
2503 unsigned int length
, gfp_t gfp_mask
);
2504 static inline struct sk_buff
*napi_alloc_skb(struct napi_struct
*napi
,
2505 unsigned int length
)
2507 return __napi_alloc_skb(napi
, length
, GFP_ATOMIC
);
2509 void napi_consume_skb(struct sk_buff
*skb
, int budget
);
2511 void __kfree_skb_flush(void);
2512 void __kfree_skb_defer(struct sk_buff
*skb
);
2515 * __dev_alloc_pages - allocate page for network Rx
2516 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2517 * @order: size of the allocation
2519 * Allocate a new page.
2521 * %NULL is returned if there is no free memory.
2523 static inline struct page
*__dev_alloc_pages(gfp_t gfp_mask
,
2526 /* This piece of code contains several assumptions.
2527 * 1. This is for device Rx, therefor a cold page is preferred.
2528 * 2. The expectation is the user wants a compound page.
2529 * 3. If requesting a order 0 page it will not be compound
2530 * due to the check to see if order has a value in prep_new_page
2531 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2532 * code in gfp_to_alloc_flags that should be enforcing this.
2534 gfp_mask
|= __GFP_COLD
| __GFP_COMP
| __GFP_MEMALLOC
;
2536 return alloc_pages_node(NUMA_NO_NODE
, gfp_mask
, order
);
2539 static inline struct page
*dev_alloc_pages(unsigned int order
)
2541 return __dev_alloc_pages(GFP_ATOMIC
| __GFP_NOWARN
, order
);
2545 * __dev_alloc_page - allocate a page for network Rx
2546 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2548 * Allocate a new page.
2550 * %NULL is returned if there is no free memory.
2552 static inline struct page
*__dev_alloc_page(gfp_t gfp_mask
)
2554 return __dev_alloc_pages(gfp_mask
, 0);
2557 static inline struct page
*dev_alloc_page(void)
2559 return dev_alloc_pages(0);
2563 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2564 * @page: The page that was allocated from skb_alloc_page
2565 * @skb: The skb that may need pfmemalloc set
2567 static inline void skb_propagate_pfmemalloc(struct page
*page
,
2568 struct sk_buff
*skb
)
2570 if (page_is_pfmemalloc(page
))
2571 skb
->pfmemalloc
= true;
2575 * skb_frag_page - retrieve the page referred to by a paged fragment
2576 * @frag: the paged fragment
2578 * Returns the &struct page associated with @frag.
2580 static inline struct page
*skb_frag_page(const skb_frag_t
*frag
)
2582 return frag
->page
.p
;
2586 * __skb_frag_ref - take an addition reference on a paged fragment.
2587 * @frag: the paged fragment
2589 * Takes an additional reference on the paged fragment @frag.
2591 static inline void __skb_frag_ref(skb_frag_t
*frag
)
2593 get_page(skb_frag_page(frag
));
2597 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2599 * @f: the fragment offset.
2601 * Takes an additional reference on the @f'th paged fragment of @skb.
2603 static inline void skb_frag_ref(struct sk_buff
*skb
, int f
)
2605 __skb_frag_ref(&skb_shinfo(skb
)->frags
[f
]);
2609 * __skb_frag_unref - release a reference on a paged fragment.
2610 * @frag: the paged fragment
2612 * Releases a reference on the paged fragment @frag.
2614 static inline void __skb_frag_unref(skb_frag_t
*frag
)
2616 put_page(skb_frag_page(frag
));
2620 * skb_frag_unref - release a reference on a paged fragment of an skb.
2622 * @f: the fragment offset
2624 * Releases a reference on the @f'th paged fragment of @skb.
2626 static inline void skb_frag_unref(struct sk_buff
*skb
, int f
)
2628 __skb_frag_unref(&skb_shinfo(skb
)->frags
[f
]);
2632 * skb_frag_address - gets the address of the data contained in a paged fragment
2633 * @frag: the paged fragment buffer
2635 * Returns the address of the data within @frag. The page must already
2638 static inline void *skb_frag_address(const skb_frag_t
*frag
)
2640 return page_address(skb_frag_page(frag
)) + frag
->page_offset
;
2644 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2645 * @frag: the paged fragment buffer
2647 * Returns the address of the data within @frag. Checks that the page
2648 * is mapped and returns %NULL otherwise.
2650 static inline void *skb_frag_address_safe(const skb_frag_t
*frag
)
2652 void *ptr
= page_address(skb_frag_page(frag
));
2656 return ptr
+ frag
->page_offset
;
2660 * __skb_frag_set_page - sets the page contained in a paged fragment
2661 * @frag: the paged fragment
2662 * @page: the page to set
2664 * Sets the fragment @frag to contain @page.
2666 static inline void __skb_frag_set_page(skb_frag_t
*frag
, struct page
*page
)
2668 frag
->page
.p
= page
;
2672 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2674 * @f: the fragment offset
2675 * @page: the page to set
2677 * Sets the @f'th fragment of @skb to contain @page.
2679 static inline void skb_frag_set_page(struct sk_buff
*skb
, int f
,
2682 __skb_frag_set_page(&skb_shinfo(skb
)->frags
[f
], page
);
2685 bool skb_page_frag_refill(unsigned int sz
, struct page_frag
*pfrag
, gfp_t prio
);
2688 * skb_frag_dma_map - maps a paged fragment via the DMA API
2689 * @dev: the device to map the fragment to
2690 * @frag: the paged fragment to map
2691 * @offset: the offset within the fragment (starting at the
2692 * fragment's own offset)
2693 * @size: the number of bytes to map
2694 * @dir: the direction of the mapping (%PCI_DMA_*)
2696 * Maps the page associated with @frag to @device.
2698 static inline dma_addr_t
skb_frag_dma_map(struct device
*dev
,
2699 const skb_frag_t
*frag
,
2700 size_t offset
, size_t size
,
2701 enum dma_data_direction dir
)
2703 return dma_map_page(dev
, skb_frag_page(frag
),
2704 frag
->page_offset
+ offset
, size
, dir
);
2707 static inline struct sk_buff
*pskb_copy(struct sk_buff
*skb
,
2710 return __pskb_copy(skb
, skb_headroom(skb
), gfp_mask
);
2714 static inline struct sk_buff
*pskb_copy_for_clone(struct sk_buff
*skb
,
2717 return __pskb_copy_fclone(skb
, skb_headroom(skb
), gfp_mask
, true);
2722 * skb_clone_writable - is the header of a clone writable
2723 * @skb: buffer to check
2724 * @len: length up to which to write
2726 * Returns true if modifying the header part of the cloned buffer
2727 * does not requires the data to be copied.
2729 static inline int skb_clone_writable(const struct sk_buff
*skb
, unsigned int len
)
2731 return !skb_header_cloned(skb
) &&
2732 skb_headroom(skb
) + len
<= skb
->hdr_len
;
2735 static inline int skb_try_make_writable(struct sk_buff
*skb
,
2736 unsigned int write_len
)
2738 return skb_cloned(skb
) && !skb_clone_writable(skb
, write_len
) &&
2739 pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
2742 static inline int __skb_cow(struct sk_buff
*skb
, unsigned int headroom
,
2747 if (headroom
> skb_headroom(skb
))
2748 delta
= headroom
- skb_headroom(skb
);
2750 if (delta
|| cloned
)
2751 return pskb_expand_head(skb
, ALIGN(delta
, NET_SKB_PAD
), 0,
2757 * skb_cow - copy header of skb when it is required
2758 * @skb: buffer to cow
2759 * @headroom: needed headroom
2761 * If the skb passed lacks sufficient headroom or its data part
2762 * is shared, data is reallocated. If reallocation fails, an error
2763 * is returned and original skb is not changed.
2765 * The result is skb with writable area skb->head...skb->tail
2766 * and at least @headroom of space at head.
2768 static inline int skb_cow(struct sk_buff
*skb
, unsigned int headroom
)
2770 return __skb_cow(skb
, headroom
, skb_cloned(skb
));
2774 * skb_cow_head - skb_cow but only making the head writable
2775 * @skb: buffer to cow
2776 * @headroom: needed headroom
2778 * This function is identical to skb_cow except that we replace the
2779 * skb_cloned check by skb_header_cloned. It should be used when
2780 * you only need to push on some header and do not need to modify
2783 static inline int skb_cow_head(struct sk_buff
*skb
, unsigned int headroom
)
2785 return __skb_cow(skb
, headroom
, skb_header_cloned(skb
));
2789 * skb_padto - pad an skbuff up to a minimal size
2790 * @skb: buffer to pad
2791 * @len: minimal length
2793 * Pads up a buffer to ensure the trailing bytes exist and are
2794 * blanked. If the buffer already contains sufficient data it
2795 * is untouched. Otherwise it is extended. Returns zero on
2796 * success. The skb is freed on error.
2798 static inline int skb_padto(struct sk_buff
*skb
, unsigned int len
)
2800 unsigned int size
= skb
->len
;
2801 if (likely(size
>= len
))
2803 return skb_pad(skb
, len
- size
);
2807 * skb_put_padto - increase size and pad an skbuff up to a minimal size
2808 * @skb: buffer to pad
2809 * @len: minimal length
2811 * Pads up a buffer to ensure the trailing bytes exist and are
2812 * blanked. If the buffer already contains sufficient data it
2813 * is untouched. Otherwise it is extended. Returns zero on
2814 * success. The skb is freed on error.
2816 static inline int skb_put_padto(struct sk_buff
*skb
, unsigned int len
)
2818 unsigned int size
= skb
->len
;
2820 if (unlikely(size
< len
)) {
2822 if (skb_pad(skb
, len
))
2824 __skb_put(skb
, len
);
2829 static inline int skb_add_data(struct sk_buff
*skb
,
2830 struct iov_iter
*from
, int copy
)
2832 const int off
= skb
->len
;
2834 if (skb
->ip_summed
== CHECKSUM_NONE
) {
2836 if (csum_and_copy_from_iter_full(skb_put(skb
, copy
), copy
,
2838 skb
->csum
= csum_block_add(skb
->csum
, csum
, off
);
2841 } else if (copy_from_iter_full(skb_put(skb
, copy
), copy
, from
))
2844 __skb_trim(skb
, off
);
2848 static inline bool skb_can_coalesce(struct sk_buff
*skb
, int i
,
2849 const struct page
*page
, int off
)
2852 const struct skb_frag_struct
*frag
= &skb_shinfo(skb
)->frags
[i
- 1];
2854 return page
== skb_frag_page(frag
) &&
2855 off
== frag
->page_offset
+ skb_frag_size(frag
);
2860 static inline int __skb_linearize(struct sk_buff
*skb
)
2862 return __pskb_pull_tail(skb
, skb
->data_len
) ? 0 : -ENOMEM
;
2866 * skb_linearize - convert paged skb to linear one
2867 * @skb: buffer to linarize
2869 * If there is no free memory -ENOMEM is returned, otherwise zero
2870 * is returned and the old skb data released.
2872 static inline int skb_linearize(struct sk_buff
*skb
)
2874 return skb_is_nonlinear(skb
) ? __skb_linearize(skb
) : 0;
2878 * skb_has_shared_frag - can any frag be overwritten
2879 * @skb: buffer to test
2881 * Return true if the skb has at least one frag that might be modified
2882 * by an external entity (as in vmsplice()/sendfile())
2884 static inline bool skb_has_shared_frag(const struct sk_buff
*skb
)
2886 return skb_is_nonlinear(skb
) &&
2887 skb_shinfo(skb
)->tx_flags
& SKBTX_SHARED_FRAG
;
2891 * skb_linearize_cow - make sure skb is linear and writable
2892 * @skb: buffer to process
2894 * If there is no free memory -ENOMEM is returned, otherwise zero
2895 * is returned and the old skb data released.
2897 static inline int skb_linearize_cow(struct sk_buff
*skb
)
2899 return skb_is_nonlinear(skb
) || skb_cloned(skb
) ?
2900 __skb_linearize(skb
) : 0;
2903 static __always_inline
void
2904 __skb_postpull_rcsum(struct sk_buff
*skb
, const void *start
, unsigned int len
,
2907 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
2908 skb
->csum
= csum_block_sub(skb
->csum
,
2909 csum_partial(start
, len
, 0), off
);
2910 else if (skb
->ip_summed
== CHECKSUM_PARTIAL
&&
2911 skb_checksum_start_offset(skb
) < 0)
2912 skb
->ip_summed
= CHECKSUM_NONE
;
2916 * skb_postpull_rcsum - update checksum for received skb after pull
2917 * @skb: buffer to update
2918 * @start: start of data before pull
2919 * @len: length of data pulled
2921 * After doing a pull on a received packet, you need to call this to
2922 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2923 * CHECKSUM_NONE so that it can be recomputed from scratch.
2925 static inline void skb_postpull_rcsum(struct sk_buff
*skb
,
2926 const void *start
, unsigned int len
)
2928 __skb_postpull_rcsum(skb
, start
, len
, 0);
2931 static __always_inline
void
2932 __skb_postpush_rcsum(struct sk_buff
*skb
, const void *start
, unsigned int len
,
2935 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
2936 skb
->csum
= csum_block_add(skb
->csum
,
2937 csum_partial(start
, len
, 0), off
);
2941 * skb_postpush_rcsum - update checksum for received skb after push
2942 * @skb: buffer to update
2943 * @start: start of data after push
2944 * @len: length of data pushed
2946 * After doing a push on a received packet, you need to call this to
2947 * update the CHECKSUM_COMPLETE checksum.
2949 static inline void skb_postpush_rcsum(struct sk_buff
*skb
,
2950 const void *start
, unsigned int len
)
2952 __skb_postpush_rcsum(skb
, start
, len
, 0);
2955 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
);
2958 * skb_push_rcsum - push skb and update receive checksum
2959 * @skb: buffer to update
2960 * @len: length of data pulled
2962 * This function performs an skb_push on the packet and updates
2963 * the CHECKSUM_COMPLETE checksum. It should be used on
2964 * receive path processing instead of skb_push unless you know
2965 * that the checksum difference is zero (e.g., a valid IP header)
2966 * or you are setting ip_summed to CHECKSUM_NONE.
2968 static inline unsigned char *skb_push_rcsum(struct sk_buff
*skb
,
2972 skb_postpush_rcsum(skb
, skb
->data
, len
);
2977 * pskb_trim_rcsum - trim received skb and update checksum
2978 * @skb: buffer to trim
2981 * This is exactly the same as pskb_trim except that it ensures the
2982 * checksum of received packets are still valid after the operation.
2985 static inline int pskb_trim_rcsum(struct sk_buff
*skb
, unsigned int len
)
2987 if (likely(len
>= skb
->len
))
2989 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
2990 skb
->ip_summed
= CHECKSUM_NONE
;
2991 return __pskb_trim(skb
, len
);
2994 static inline int __skb_trim_rcsum(struct sk_buff
*skb
, unsigned int len
)
2996 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
2997 skb
->ip_summed
= CHECKSUM_NONE
;
2998 __skb_trim(skb
, len
);
3002 static inline int __skb_grow_rcsum(struct sk_buff
*skb
, unsigned int len
)
3004 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
3005 skb
->ip_summed
= CHECKSUM_NONE
;
3006 return __skb_grow(skb
, len
);
3009 #define skb_queue_walk(queue, skb) \
3010 for (skb = (queue)->next; \
3011 skb != (struct sk_buff *)(queue); \
3014 #define skb_queue_walk_safe(queue, skb, tmp) \
3015 for (skb = (queue)->next, tmp = skb->next; \
3016 skb != (struct sk_buff *)(queue); \
3017 skb = tmp, tmp = skb->next)
3019 #define skb_queue_walk_from(queue, skb) \
3020 for (; skb != (struct sk_buff *)(queue); \
3023 #define skb_queue_walk_from_safe(queue, skb, tmp) \
3024 for (tmp = skb->next; \
3025 skb != (struct sk_buff *)(queue); \
3026 skb = tmp, tmp = skb->next)
3028 #define skb_queue_reverse_walk(queue, skb) \
3029 for (skb = (queue)->prev; \
3030 skb != (struct sk_buff *)(queue); \
3033 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
3034 for (skb = (queue)->prev, tmp = skb->prev; \
3035 skb != (struct sk_buff *)(queue); \
3036 skb = tmp, tmp = skb->prev)
3038 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
3039 for (tmp = skb->prev; \
3040 skb != (struct sk_buff *)(queue); \
3041 skb = tmp, tmp = skb->prev)
3043 static inline bool skb_has_frag_list(const struct sk_buff
*skb
)
3045 return skb_shinfo(skb
)->frag_list
!= NULL
;
3048 static inline void skb_frag_list_init(struct sk_buff
*skb
)
3050 skb_shinfo(skb
)->frag_list
= NULL
;
3053 #define skb_walk_frags(skb, iter) \
3054 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3057 int __skb_wait_for_more_packets(struct sock
*sk
, int *err
, long *timeo_p
,
3058 const struct sk_buff
*skb
);
3059 struct sk_buff
*__skb_try_recv_datagram(struct sock
*sk
, unsigned flags
,
3060 void (*destructor
)(struct sock
*sk
,
3061 struct sk_buff
*skb
),
3062 int *peeked
, int *off
, int *err
,
3063 struct sk_buff
**last
);
3064 struct sk_buff
*__skb_recv_datagram(struct sock
*sk
, unsigned flags
,
3065 void (*destructor
)(struct sock
*sk
,
3066 struct sk_buff
*skb
),
3067 int *peeked
, int *off
, int *err
);
3068 struct sk_buff
*skb_recv_datagram(struct sock
*sk
, unsigned flags
, int noblock
,
3070 unsigned int datagram_poll(struct file
*file
, struct socket
*sock
,
3071 struct poll_table_struct
*wait
);
3072 int skb_copy_datagram_iter(const struct sk_buff
*from
, int offset
,
3073 struct iov_iter
*to
, int size
);
3074 static inline int skb_copy_datagram_msg(const struct sk_buff
*from
, int offset
,
3075 struct msghdr
*msg
, int size
)
3077 return skb_copy_datagram_iter(from
, offset
, &msg
->msg_iter
, size
);
3079 int skb_copy_and_csum_datagram_msg(struct sk_buff
*skb
, int hlen
,
3080 struct msghdr
*msg
);
3081 int skb_copy_datagram_from_iter(struct sk_buff
*skb
, int offset
,
3082 struct iov_iter
*from
, int len
);
3083 int zerocopy_sg_from_iter(struct sk_buff
*skb
, struct iov_iter
*frm
);
3084 void skb_free_datagram(struct sock
*sk
, struct sk_buff
*skb
);
3085 void __skb_free_datagram_locked(struct sock
*sk
, struct sk_buff
*skb
, int len
);
3086 static inline void skb_free_datagram_locked(struct sock
*sk
,
3087 struct sk_buff
*skb
)
3089 __skb_free_datagram_locked(sk
, skb
, 0);
3091 int skb_kill_datagram(struct sock
*sk
, struct sk_buff
*skb
, unsigned int flags
);
3092 int skb_copy_bits(const struct sk_buff
*skb
, int offset
, void *to
, int len
);
3093 int skb_store_bits(struct sk_buff
*skb
, int offset
, const void *from
, int len
);
3094 __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
, int offset
, u8
*to
,
3095 int len
, __wsum csum
);
3096 int skb_splice_bits(struct sk_buff
*skb
, struct sock
*sk
, unsigned int offset
,
3097 struct pipe_inode_info
*pipe
, unsigned int len
,
3098 unsigned int flags
);
3099 void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
);
3100 unsigned int skb_zerocopy_headlen(const struct sk_buff
*from
);
3101 int skb_zerocopy(struct sk_buff
*to
, struct sk_buff
*from
,
3103 void skb_split(struct sk_buff
*skb
, struct sk_buff
*skb1
, const u32 len
);
3104 int skb_shift(struct sk_buff
*tgt
, struct sk_buff
*skb
, int shiftlen
);
3105 void skb_scrub_packet(struct sk_buff
*skb
, bool xnet
);
3106 unsigned int skb_gso_transport_seglen(const struct sk_buff
*skb
);
3107 bool skb_gso_validate_mtu(const struct sk_buff
*skb
, unsigned int mtu
);
3108 struct sk_buff
*skb_segment(struct sk_buff
*skb
, netdev_features_t features
);
3109 struct sk_buff
*skb_vlan_untag(struct sk_buff
*skb
);
3110 int skb_ensure_writable(struct sk_buff
*skb
, int write_len
);
3111 int __skb_vlan_pop(struct sk_buff
*skb
, u16
*vlan_tci
);
3112 int skb_vlan_pop(struct sk_buff
*skb
);
3113 int skb_vlan_push(struct sk_buff
*skb
, __be16 vlan_proto
, u16 vlan_tci
);
3114 struct sk_buff
*pskb_extract(struct sk_buff
*skb
, int off
, int to_copy
,
3117 static inline int memcpy_from_msg(void *data
, struct msghdr
*msg
, int len
)
3119 return copy_from_iter_full(data
, len
, &msg
->msg_iter
) ? 0 : -EFAULT
;
3122 static inline int memcpy_to_msg(struct msghdr
*msg
, void *data
, int len
)
3124 return copy_to_iter(data
, len
, &msg
->msg_iter
) == len
? 0 : -EFAULT
;
3127 struct skb_checksum_ops
{
3128 __wsum (*update
)(const void *mem
, int len
, __wsum wsum
);
3129 __wsum (*combine
)(__wsum csum
, __wsum csum2
, int offset
, int len
);
3132 __wsum
__skb_checksum(const struct sk_buff
*skb
, int offset
, int len
,
3133 __wsum csum
, const struct skb_checksum_ops
*ops
);
3134 __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
, int len
,
3137 static inline void * __must_check
3138 __skb_header_pointer(const struct sk_buff
*skb
, int offset
,
3139 int len
, void *data
, int hlen
, void *buffer
)
3141 if (hlen
- offset
>= len
)
3142 return data
+ offset
;
3145 skb_copy_bits(skb
, offset
, buffer
, len
) < 0)
3151 static inline void * __must_check
3152 skb_header_pointer(const struct sk_buff
*skb
, int offset
, int len
, void *buffer
)
3154 return __skb_header_pointer(skb
, offset
, len
, skb
->data
,
3155 skb_headlen(skb
), buffer
);
3159 * skb_needs_linearize - check if we need to linearize a given skb
3160 * depending on the given device features.
3161 * @skb: socket buffer to check
3162 * @features: net device features
3164 * Returns true if either:
3165 * 1. skb has frag_list and the device doesn't support FRAGLIST, or
3166 * 2. skb is fragmented and the device does not support SG.
3168 static inline bool skb_needs_linearize(struct sk_buff
*skb
,
3169 netdev_features_t features
)
3171 return skb_is_nonlinear(skb
) &&
3172 ((skb_has_frag_list(skb
) && !(features
& NETIF_F_FRAGLIST
)) ||
3173 (skb_shinfo(skb
)->nr_frags
&& !(features
& NETIF_F_SG
)));
3176 static inline void skb_copy_from_linear_data(const struct sk_buff
*skb
,
3178 const unsigned int len
)
3180 memcpy(to
, skb
->data
, len
);
3183 static inline void skb_copy_from_linear_data_offset(const struct sk_buff
*skb
,
3184 const int offset
, void *to
,
3185 const unsigned int len
)
3187 memcpy(to
, skb
->data
+ offset
, len
);
3190 static inline void skb_copy_to_linear_data(struct sk_buff
*skb
,
3192 const unsigned int len
)
3194 memcpy(skb
->data
, from
, len
);
3197 static inline void skb_copy_to_linear_data_offset(struct sk_buff
*skb
,
3200 const unsigned int len
)
3202 memcpy(skb
->data
+ offset
, from
, len
);
3205 void skb_init(void);
3207 static inline ktime_t
skb_get_ktime(const struct sk_buff
*skb
)
3213 * skb_get_timestamp - get timestamp from a skb
3214 * @skb: skb to get stamp from
3215 * @stamp: pointer to struct timeval to store stamp in
3217 * Timestamps are stored in the skb as offsets to a base timestamp.
3218 * This function converts the offset back to a struct timeval and stores
3221 static inline void skb_get_timestamp(const struct sk_buff
*skb
,
3222 struct timeval
*stamp
)
3224 *stamp
= ktime_to_timeval(skb
->tstamp
);
3227 static inline void skb_get_timestampns(const struct sk_buff
*skb
,
3228 struct timespec
*stamp
)
3230 *stamp
= ktime_to_timespec(skb
->tstamp
);
3233 static inline void __net_timestamp(struct sk_buff
*skb
)
3235 skb
->tstamp
= ktime_get_real();
3238 static inline ktime_t
net_timedelta(ktime_t t
)
3240 return ktime_sub(ktime_get_real(), t
);
3243 static inline ktime_t
net_invalid_timestamp(void)
3248 struct sk_buff
*skb_clone_sk(struct sk_buff
*skb
);
3250 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3252 void skb_clone_tx_timestamp(struct sk_buff
*skb
);
3253 bool skb_defer_rx_timestamp(struct sk_buff
*skb
);
3255 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3257 static inline void skb_clone_tx_timestamp(struct sk_buff
*skb
)
3261 static inline bool skb_defer_rx_timestamp(struct sk_buff
*skb
)
3266 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3269 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3271 * PHY drivers may accept clones of transmitted packets for
3272 * timestamping via their phy_driver.txtstamp method. These drivers
3273 * must call this function to return the skb back to the stack with a
3276 * @skb: clone of the the original outgoing packet
3277 * @hwtstamps: hardware time stamps
3280 void skb_complete_tx_timestamp(struct sk_buff
*skb
,
3281 struct skb_shared_hwtstamps
*hwtstamps
);
3283 void __skb_tstamp_tx(struct sk_buff
*orig_skb
,
3284 struct skb_shared_hwtstamps
*hwtstamps
,
3285 struct sock
*sk
, int tstype
);
3288 * skb_tstamp_tx - queue clone of skb with send time stamps
3289 * @orig_skb: the original outgoing packet
3290 * @hwtstamps: hardware time stamps, may be NULL if not available
3292 * If the skb has a socket associated, then this function clones the
3293 * skb (thus sharing the actual data and optional structures), stores
3294 * the optional hardware time stamping information (if non NULL) or
3295 * generates a software time stamp (otherwise), then queues the clone
3296 * to the error queue of the socket. Errors are silently ignored.
3298 void skb_tstamp_tx(struct sk_buff
*orig_skb
,
3299 struct skb_shared_hwtstamps
*hwtstamps
);
3301 static inline void sw_tx_timestamp(struct sk_buff
*skb
)
3303 if (skb_shinfo(skb
)->tx_flags
& SKBTX_SW_TSTAMP
&&
3304 !(skb_shinfo(skb
)->tx_flags
& SKBTX_IN_PROGRESS
))
3305 skb_tstamp_tx(skb
, NULL
);
3309 * skb_tx_timestamp() - Driver hook for transmit timestamping
3311 * Ethernet MAC Drivers should call this function in their hard_xmit()
3312 * function immediately before giving the sk_buff to the MAC hardware.
3314 * Specifically, one should make absolutely sure that this function is
3315 * called before TX completion of this packet can trigger. Otherwise
3316 * the packet could potentially already be freed.
3318 * @skb: A socket buffer.
3320 static inline void skb_tx_timestamp(struct sk_buff
*skb
)
3322 skb_clone_tx_timestamp(skb
);
3323 sw_tx_timestamp(skb
);
3327 * skb_complete_wifi_ack - deliver skb with wifi status
3329 * @skb: the original outgoing packet
3330 * @acked: ack status
3333 void skb_complete_wifi_ack(struct sk_buff
*skb
, bool acked
);
3335 __sum16
__skb_checksum_complete_head(struct sk_buff
*skb
, int len
);
3336 __sum16
__skb_checksum_complete(struct sk_buff
*skb
);
3338 static inline int skb_csum_unnecessary(const struct sk_buff
*skb
)
3340 return ((skb
->ip_summed
== CHECKSUM_UNNECESSARY
) ||
3342 (skb
->ip_summed
== CHECKSUM_PARTIAL
&&
3343 skb_checksum_start_offset(skb
) >= 0));
3347 * skb_checksum_complete - Calculate checksum of an entire packet
3348 * @skb: packet to process
3350 * This function calculates the checksum over the entire packet plus
3351 * the value of skb->csum. The latter can be used to supply the
3352 * checksum of a pseudo header as used by TCP/UDP. It returns the
3355 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
3356 * this function can be used to verify that checksum on received
3357 * packets. In that case the function should return zero if the
3358 * checksum is correct. In particular, this function will return zero
3359 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3360 * hardware has already verified the correctness of the checksum.
3362 static inline __sum16
skb_checksum_complete(struct sk_buff
*skb
)
3364 return skb_csum_unnecessary(skb
) ?
3365 0 : __skb_checksum_complete(skb
);
3368 static inline void __skb_decr_checksum_unnecessary(struct sk_buff
*skb
)
3370 if (skb
->ip_summed
== CHECKSUM_UNNECESSARY
) {
3371 if (skb
->csum_level
== 0)
3372 skb
->ip_summed
= CHECKSUM_NONE
;
3378 static inline void __skb_incr_checksum_unnecessary(struct sk_buff
*skb
)
3380 if (skb
->ip_summed
== CHECKSUM_UNNECESSARY
) {
3381 if (skb
->csum_level
< SKB_MAX_CSUM_LEVEL
)
3383 } else if (skb
->ip_summed
== CHECKSUM_NONE
) {
3384 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
3385 skb
->csum_level
= 0;
3389 static inline void __skb_mark_checksum_bad(struct sk_buff
*skb
)
3391 /* Mark current checksum as bad (typically called from GRO
3392 * path). In the case that ip_summed is CHECKSUM_NONE
3393 * this must be the first checksum encountered in the packet.
3394 * When ip_summed is CHECKSUM_UNNECESSARY, this is the first
3395 * checksum after the last one validated. For UDP, a zero
3396 * checksum can not be marked as bad.
3399 if (skb
->ip_summed
== CHECKSUM_NONE
||
3400 skb
->ip_summed
== CHECKSUM_UNNECESSARY
)
3404 /* Check if we need to perform checksum complete validation.
3406 * Returns true if checksum complete is needed, false otherwise
3407 * (either checksum is unnecessary or zero checksum is allowed).
3409 static inline bool __skb_checksum_validate_needed(struct sk_buff
*skb
,
3413 if (skb_csum_unnecessary(skb
) || (zero_okay
&& !check
)) {
3414 skb
->csum_valid
= 1;
3415 __skb_decr_checksum_unnecessary(skb
);
3422 /* For small packets <= CHECKSUM_BREAK peform checksum complete directly
3425 #define CHECKSUM_BREAK 76
3427 /* Unset checksum-complete
3429 * Unset checksum complete can be done when packet is being modified
3430 * (uncompressed for instance) and checksum-complete value is
3433 static inline void skb_checksum_complete_unset(struct sk_buff
*skb
)
3435 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
3436 skb
->ip_summed
= CHECKSUM_NONE
;
3439 /* Validate (init) checksum based on checksum complete.
3442 * 0: checksum is validated or try to in skb_checksum_complete. In the latter
3443 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3444 * checksum is stored in skb->csum for use in __skb_checksum_complete
3445 * non-zero: value of invalid checksum
3448 static inline __sum16
__skb_checksum_validate_complete(struct sk_buff
*skb
,
3452 if (skb
->ip_summed
== CHECKSUM_COMPLETE
) {
3453 if (!csum_fold(csum_add(psum
, skb
->csum
))) {
3454 skb
->csum_valid
= 1;
3457 } else if (skb
->csum_bad
) {
3458 /* ip_summed == CHECKSUM_NONE in this case */
3459 return (__force __sum16
)1;
3464 if (complete
|| skb
->len
<= CHECKSUM_BREAK
) {
3467 csum
= __skb_checksum_complete(skb
);
3468 skb
->csum_valid
= !csum
;
3475 static inline __wsum
null_compute_pseudo(struct sk_buff
*skb
, int proto
)
3480 /* Perform checksum validate (init). Note that this is a macro since we only
3481 * want to calculate the pseudo header which is an input function if necessary.
3482 * First we try to validate without any computation (checksum unnecessary) and
3483 * then calculate based on checksum complete calling the function to compute
3487 * 0: checksum is validated or try to in skb_checksum_complete
3488 * non-zero: value of invalid checksum
3490 #define __skb_checksum_validate(skb, proto, complete, \
3491 zero_okay, check, compute_pseudo) \
3493 __sum16 __ret = 0; \
3494 skb->csum_valid = 0; \
3495 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
3496 __ret = __skb_checksum_validate_complete(skb, \
3497 complete, compute_pseudo(skb, proto)); \
3501 #define skb_checksum_init(skb, proto, compute_pseudo) \
3502 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3504 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3505 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3507 #define skb_checksum_validate(skb, proto, compute_pseudo) \
3508 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3510 #define skb_checksum_validate_zero_check(skb, proto, check, \
3512 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3514 #define skb_checksum_simple_validate(skb) \
3515 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3517 static inline bool __skb_checksum_convert_check(struct sk_buff
*skb
)
3519 return (skb
->ip_summed
== CHECKSUM_NONE
&&
3520 skb
->csum_valid
&& !skb
->csum_bad
);
3523 static inline void __skb_checksum_convert(struct sk_buff
*skb
,
3524 __sum16 check
, __wsum pseudo
)
3526 skb
->csum
= ~pseudo
;
3527 skb
->ip_summed
= CHECKSUM_COMPLETE
;
3530 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo) \
3532 if (__skb_checksum_convert_check(skb)) \
3533 __skb_checksum_convert(skb, check, \
3534 compute_pseudo(skb, proto)); \
3537 static inline void skb_remcsum_adjust_partial(struct sk_buff
*skb
, void *ptr
,
3538 u16 start
, u16 offset
)
3540 skb
->ip_summed
= CHECKSUM_PARTIAL
;
3541 skb
->csum_start
= ((unsigned char *)ptr
+ start
) - skb
->head
;
3542 skb
->csum_offset
= offset
- start
;
3545 /* Update skbuf and packet to reflect the remote checksum offload operation.
3546 * When called, ptr indicates the starting point for skb->csum when
3547 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3548 * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3550 static inline void skb_remcsum_process(struct sk_buff
*skb
, void *ptr
,
3551 int start
, int offset
, bool nopartial
)
3556 skb_remcsum_adjust_partial(skb
, ptr
, start
, offset
);
3560 if (unlikely(skb
->ip_summed
!= CHECKSUM_COMPLETE
)) {
3561 __skb_checksum_complete(skb
);
3562 skb_postpull_rcsum(skb
, skb
->data
, ptr
- (void *)skb
->data
);
3565 delta
= remcsum_adjust(ptr
, skb
->csum
, start
, offset
);
3567 /* Adjust skb->csum since we changed the packet */
3568 skb
->csum
= csum_add(skb
->csum
, delta
);
3571 static inline struct nf_conntrack
*skb_nfct(const struct sk_buff
*skb
)
3573 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3574 return (void *)(skb
->_nfct
& SKB_NFCT_PTRMASK
);
3580 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3581 void nf_conntrack_destroy(struct nf_conntrack
*nfct
);
3582 static inline void nf_conntrack_put(struct nf_conntrack
*nfct
)
3584 if (nfct
&& atomic_dec_and_test(&nfct
->use
))
3585 nf_conntrack_destroy(nfct
);
3587 static inline void nf_conntrack_get(struct nf_conntrack
*nfct
)
3590 atomic_inc(&nfct
->use
);
3593 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3594 static inline void nf_bridge_put(struct nf_bridge_info
*nf_bridge
)
3596 if (nf_bridge
&& atomic_dec_and_test(&nf_bridge
->use
))
3599 static inline void nf_bridge_get(struct nf_bridge_info
*nf_bridge
)
3602 atomic_inc(&nf_bridge
->use
);
3604 #endif /* CONFIG_BRIDGE_NETFILTER */
3605 static inline void nf_reset(struct sk_buff
*skb
)
3607 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3608 nf_conntrack_put(skb_nfct(skb
));
3611 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3612 nf_bridge_put(skb
->nf_bridge
);
3613 skb
->nf_bridge
= NULL
;
3617 static inline void nf_reset_trace(struct sk_buff
*skb
)
3619 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3624 /* Note: This doesn't put any conntrack and bridge info in dst. */
3625 static inline void __nf_copy(struct sk_buff
*dst
, const struct sk_buff
*src
,
3628 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3629 dst
->_nfct
= src
->_nfct
;
3630 nf_conntrack_get(skb_nfct(src
));
3632 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3633 dst
->nf_bridge
= src
->nf_bridge
;
3634 nf_bridge_get(src
->nf_bridge
);
3636 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3638 dst
->nf_trace
= src
->nf_trace
;
3642 static inline void nf_copy(struct sk_buff
*dst
, const struct sk_buff
*src
)
3644 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3645 nf_conntrack_put(skb_nfct(dst
));
3647 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3648 nf_bridge_put(dst
->nf_bridge
);
3650 __nf_copy(dst
, src
, true);
3653 #ifdef CONFIG_NETWORK_SECMARK
3654 static inline void skb_copy_secmark(struct sk_buff
*to
, const struct sk_buff
*from
)
3656 to
->secmark
= from
->secmark
;
3659 static inline void skb_init_secmark(struct sk_buff
*skb
)
3664 static inline void skb_copy_secmark(struct sk_buff
*to
, const struct sk_buff
*from
)
3667 static inline void skb_init_secmark(struct sk_buff
*skb
)
3671 static inline bool skb_irq_freeable(const struct sk_buff
*skb
)
3673 return !skb
->destructor
&&
3674 #if IS_ENABLED(CONFIG_XFRM)
3678 !skb
->_skb_refdst
&&
3679 !skb_has_frag_list(skb
);
3682 static inline void skb_set_queue_mapping(struct sk_buff
*skb
, u16 queue_mapping
)
3684 skb
->queue_mapping
= queue_mapping
;
3687 static inline u16
skb_get_queue_mapping(const struct sk_buff
*skb
)
3689 return skb
->queue_mapping
;
3692 static inline void skb_copy_queue_mapping(struct sk_buff
*to
, const struct sk_buff
*from
)
3694 to
->queue_mapping
= from
->queue_mapping
;
3697 static inline void skb_record_rx_queue(struct sk_buff
*skb
, u16 rx_queue
)
3699 skb
->queue_mapping
= rx_queue
+ 1;
3702 static inline u16
skb_get_rx_queue(const struct sk_buff
*skb
)
3704 return skb
->queue_mapping
- 1;
3707 static inline bool skb_rx_queue_recorded(const struct sk_buff
*skb
)
3709 return skb
->queue_mapping
!= 0;
3712 static inline void skb_set_dst_pending_confirm(struct sk_buff
*skb
, u32 val
)
3714 skb
->dst_pending_confirm
= val
;
3717 static inline bool skb_get_dst_pending_confirm(const struct sk_buff
*skb
)
3719 return skb
->dst_pending_confirm
!= 0;
3722 static inline struct sec_path
*skb_sec_path(struct sk_buff
*skb
)
3731 /* Keeps track of mac header offset relative to skb->head.
3732 * It is useful for TSO of Tunneling protocol. e.g. GRE.
3733 * For non-tunnel skb it points to skb_mac_header() and for
3734 * tunnel skb it points to outer mac header.
3735 * Keeps track of level of encapsulation of network headers.
3746 #define SKB_SGO_CB_OFFSET 32
3747 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
3749 static inline int skb_tnl_header_len(const struct sk_buff
*inner_skb
)
3751 return (skb_mac_header(inner_skb
) - inner_skb
->head
) -
3752 SKB_GSO_CB(inner_skb
)->mac_offset
;
3755 static inline int gso_pskb_expand_head(struct sk_buff
*skb
, int extra
)
3757 int new_headroom
, headroom
;
3760 headroom
= skb_headroom(skb
);
3761 ret
= pskb_expand_head(skb
, extra
, 0, GFP_ATOMIC
);
3765 new_headroom
= skb_headroom(skb
);
3766 SKB_GSO_CB(skb
)->mac_offset
+= (new_headroom
- headroom
);
3770 static inline void gso_reset_checksum(struct sk_buff
*skb
, __wsum res
)
3772 /* Do not update partial checksums if remote checksum is enabled. */
3773 if (skb
->remcsum_offload
)
3776 SKB_GSO_CB(skb
)->csum
= res
;
3777 SKB_GSO_CB(skb
)->csum_start
= skb_checksum_start(skb
) - skb
->head
;
3780 /* Compute the checksum for a gso segment. First compute the checksum value
3781 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
3782 * then add in skb->csum (checksum from csum_start to end of packet).
3783 * skb->csum and csum_start are then updated to reflect the checksum of the
3784 * resultant packet starting from the transport header-- the resultant checksum
3785 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
3788 static inline __sum16
gso_make_checksum(struct sk_buff
*skb
, __wsum res
)
3790 unsigned char *csum_start
= skb_transport_header(skb
);
3791 int plen
= (skb
->head
+ SKB_GSO_CB(skb
)->csum_start
) - csum_start
;
3792 __wsum partial
= SKB_GSO_CB(skb
)->csum
;
3794 SKB_GSO_CB(skb
)->csum
= res
;
3795 SKB_GSO_CB(skb
)->csum_start
= csum_start
- skb
->head
;
3797 return csum_fold(csum_partial(csum_start
, plen
, partial
));
3800 static inline bool skb_is_gso(const struct sk_buff
*skb
)
3802 return skb_shinfo(skb
)->gso_size
;
3805 /* Note: Should be called only if skb_is_gso(skb) is true */
3806 static inline bool skb_is_gso_v6(const struct sk_buff
*skb
)
3808 return skb_shinfo(skb
)->gso_type
& SKB_GSO_TCPV6
;
3811 static inline void skb_gso_reset(struct sk_buff
*skb
)
3813 skb_shinfo(skb
)->gso_size
= 0;
3814 skb_shinfo(skb
)->gso_segs
= 0;
3815 skb_shinfo(skb
)->gso_type
= 0;
3818 void __skb_warn_lro_forwarding(const struct sk_buff
*skb
);
3820 static inline bool skb_warn_if_lro(const struct sk_buff
*skb
)
3822 /* LRO sets gso_size but not gso_type, whereas if GSO is really
3823 * wanted then gso_type will be set. */
3824 const struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
3826 if (skb_is_nonlinear(skb
) && shinfo
->gso_size
!= 0 &&
3827 unlikely(shinfo
->gso_type
== 0)) {
3828 __skb_warn_lro_forwarding(skb
);
3834 static inline void skb_forward_csum(struct sk_buff
*skb
)
3836 /* Unfortunately we don't support this one. Any brave souls? */
3837 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
3838 skb
->ip_summed
= CHECKSUM_NONE
;
3842 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
3843 * @skb: skb to check
3845 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
3846 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
3847 * use this helper, to document places where we make this assertion.
3849 static inline void skb_checksum_none_assert(const struct sk_buff
*skb
)
3852 BUG_ON(skb
->ip_summed
!= CHECKSUM_NONE
);
3856 bool skb_partial_csum_set(struct sk_buff
*skb
, u16 start
, u16 off
);
3858 int skb_checksum_setup(struct sk_buff
*skb
, bool recalculate
);
3859 struct sk_buff
*skb_checksum_trimmed(struct sk_buff
*skb
,
3860 unsigned int transport_len
,
3861 __sum16(*skb_chkf
)(struct sk_buff
*skb
));
3864 * skb_head_is_locked - Determine if the skb->head is locked down
3865 * @skb: skb to check
3867 * The head on skbs build around a head frag can be removed if they are
3868 * not cloned. This function returns true if the skb head is locked down
3869 * due to either being allocated via kmalloc, or by being a clone with
3870 * multiple references to the head.
3872 static inline bool skb_head_is_locked(const struct sk_buff
*skb
)
3874 return !skb
->head_frag
|| skb_cloned(skb
);
3878 * skb_gso_network_seglen - Return length of individual segments of a gso packet
3882 * skb_gso_network_seglen is used to determine the real size of the
3883 * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
3885 * The MAC/L2 header is not accounted for.
3887 static inline unsigned int skb_gso_network_seglen(const struct sk_buff
*skb
)
3889 unsigned int hdr_len
= skb_transport_header(skb
) -
3890 skb_network_header(skb
);
3891 return hdr_len
+ skb_gso_transport_seglen(skb
);
3894 /* Local Checksum Offload.
3895 * Compute outer checksum based on the assumption that the
3896 * inner checksum will be offloaded later.
3897 * See Documentation/networking/checksum-offloads.txt for
3898 * explanation of how this works.
3899 * Fill in outer checksum adjustment (e.g. with sum of outer
3900 * pseudo-header) before calling.
3901 * Also ensure that inner checksum is in linear data area.
3903 static inline __wsum
lco_csum(struct sk_buff
*skb
)
3905 unsigned char *csum_start
= skb_checksum_start(skb
);
3906 unsigned char *l4_hdr
= skb_transport_header(skb
);
3909 /* Start with complement of inner checksum adjustment */
3910 partial
= ~csum_unfold(*(__force __sum16
*)(csum_start
+
3913 /* Add in checksum of our headers (incl. outer checksum
3914 * adjustment filled in by caller) and return result.
3916 return csum_partial(l4_hdr
, csum_start
- l4_hdr
, partial
);
3919 #endif /* __KERNEL__ */
3920 #endif /* _LINUX_SKBUFF_H */