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 <net/flow_dissector.h>
38 #include <linux/splice.h>
39 #include <linux/in6.h>
42 /* The interface for checksum offload between the stack and networking drivers
45 * A. IP checksum related features
47 * Drivers advertise checksum offload capabilities in the features of a device.
48 * From the stack's point of view these are capabilities offered by the driver,
49 * a driver typically only advertises features that it is capable of offloading
52 * The checksum related features are:
54 * NETIF_F_HW_CSUM - The driver (or its device) is able to compute one
55 * IP (one's complement) checksum for any combination
56 * of protocols or protocol layering. The checksum is
57 * computed and set in a packet per the CHECKSUM_PARTIAL
58 * interface (see below).
60 * NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain
61 * TCP or UDP packets over IPv4. These are specifically
62 * unencapsulated packets of the form IPv4|TCP or
63 * IPv4|UDP where the Protocol field in the IPv4 header
64 * is TCP or UDP. The IPv4 header may contain IP options
65 * This feature cannot be set in features for a device
66 * with NETIF_F_HW_CSUM also set. This feature is being
67 * DEPRECATED (see below).
69 * NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain
70 * TCP or UDP packets over IPv6. These are specifically
71 * unencapsulated packets of the form IPv6|TCP or
72 * IPv4|UDP where the Next Header field in the IPv6
73 * header is either TCP or UDP. IPv6 extension headers
74 * are not supported with this feature. This feature
75 * cannot be set in features for a device with
76 * NETIF_F_HW_CSUM also set. This feature is being
77 * DEPRECATED (see below).
79 * NETIF_F_RXCSUM - Driver (device) performs receive checksum offload.
80 * This flag is used only used to disable the RX checksum
81 * feature for a device. The stack will accept receive
82 * checksum indication in packets received on a device
83 * regardless of whether NETIF_F_RXCSUM is set.
85 * B. Checksumming of received packets by device. Indication of checksum
86 * verification is in set skb->ip_summed. Possible values are:
90 * Device did not checksum this packet e.g. due to lack of capabilities.
91 * The packet contains full (though not verified) checksum in packet but
92 * not in skb->csum. Thus, skb->csum is undefined in this case.
94 * CHECKSUM_UNNECESSARY:
96 * The hardware you're dealing with doesn't calculate the full checksum
97 * (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
98 * for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
99 * if their checksums are okay. skb->csum is still undefined in this case
100 * though. A driver or device must never modify the checksum field in the
101 * packet even if checksum is verified.
103 * CHECKSUM_UNNECESSARY is applicable to following protocols:
104 * TCP: IPv6 and IPv4.
105 * UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
106 * zero UDP checksum for either IPv4 or IPv6, the networking stack
107 * may perform further validation in this case.
108 * GRE: only if the checksum is present in the header.
109 * SCTP: indicates the CRC in SCTP header has been validated.
111 * skb->csum_level indicates the number of consecutive checksums found in
112 * the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
113 * For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
114 * and a device is able to verify the checksums for UDP (possibly zero),
115 * GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
116 * two. If the device were only able to verify the UDP checksum and not
117 * GRE, either because it doesn't support GRE checksum of because GRE
118 * checksum is bad, skb->csum_level would be set to zero (TCP checksum is
119 * not considered in this case).
123 * This is the most generic way. The device supplied checksum of the _whole_
124 * packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
125 * hardware doesn't need to parse L3/L4 headers to implement this.
127 * Note: Even if device supports only some protocols, but is able to produce
128 * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
132 * A checksum is set up to be offloaded to a device as described in the
133 * output description for CHECKSUM_PARTIAL. This may occur on a packet
134 * received directly from another Linux OS, e.g., a virtualized Linux kernel
135 * on the same host, or it may be set in the input path in GRO or remote
136 * checksum offload. For the purposes of checksum verification, the checksum
137 * referred to by skb->csum_start + skb->csum_offset and any preceding
138 * checksums in the packet are considered verified. Any checksums in the
139 * packet that are after the checksum being offloaded are not considered to
142 * C. Checksumming on transmit for non-GSO. The stack requests checksum offload
143 * in the skb->ip_summed for a packet. Values are:
147 * The driver is required to checksum the packet as seen by hard_start_xmit()
148 * from skb->csum_start up to the end, and to record/write the checksum at
149 * offset skb->csum_start + skb->csum_offset. A driver may verify that the
150 * csum_start and csum_offset values are valid values given the length and
151 * offset of the packet, however they should not attempt to validate that the
152 * checksum refers to a legitimate transport layer checksum-- it is the
153 * purview of the stack to validate that csum_start and csum_offset are set
156 * When the stack requests checksum offload for a packet, the driver MUST
157 * ensure that the checksum is set correctly. A driver can either offload the
158 * checksum calculation to the device, or call skb_checksum_help (in the case
159 * that the device does not support offload for a particular checksum).
161 * NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of
162 * NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate
163 * checksum offload capability. If a device has limited checksum capabilities
164 * (for instance can only perform NETIF_F_IP_CSUM or NETIF_F_IPV6_CSUM as
165 * described above) a helper function can be called to resolve
166 * CHECKSUM_PARTIAL. The helper functions are skb_csum_off_chk*. The helper
167 * function takes a spec argument that describes the protocol layer that is
168 * supported for checksum offload and can be called for each packet. If a
169 * packet does not match the specification for offload, skb_checksum_help
170 * is called to resolve the checksum.
174 * The skb was already checksummed by the protocol, or a checksum is not
177 * CHECKSUM_UNNECESSARY:
179 * This has the same meaning on as CHECKSUM_NONE for checksum offload on
183 * Not used in checksum output. If a driver observes a packet with this value
184 * set in skbuff, if should treat as CHECKSUM_NONE being set.
186 * D. Non-IP checksum (CRC) offloads
188 * NETIF_F_SCTP_CRC - This feature indicates that a device is capable of
189 * offloading the SCTP CRC in a packet. To perform this offload the stack
190 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
191 * accordingly. Note the there is no indication in the skbuff that the
192 * CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports
193 * both IP checksum offload and SCTP CRC offload must verify which offload
194 * is configured for a packet presumably by inspecting packet headers.
196 * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
197 * offloading the FCOE CRC in a packet. To perform this offload the stack
198 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
199 * accordingly. Note the there is no indication in the skbuff that the
200 * CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports
201 * both IP checksum offload and FCOE CRC offload must verify which offload
202 * is configured for a packet presumably by inspecting packet headers.
204 * E. Checksumming on output with GSO.
206 * In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload
207 * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
208 * gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as
209 * part of the GSO operation is implied. If a checksum is being offloaded
210 * with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset
211 * are set to refer to the outermost checksum being offload (two offloaded
212 * checksums are possible with UDP encapsulation).
215 /* Don't change this without changing skb_csum_unnecessary! */
216 #define CHECKSUM_NONE 0
217 #define CHECKSUM_UNNECESSARY 1
218 #define CHECKSUM_COMPLETE 2
219 #define CHECKSUM_PARTIAL 3
221 /* Maximum value in skb->csum_level */
222 #define SKB_MAX_CSUM_LEVEL 3
224 #define SKB_DATA_ALIGN(X) ALIGN(X, SMP_CACHE_BYTES)
225 #define SKB_WITH_OVERHEAD(X) \
226 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
227 #define SKB_MAX_ORDER(X, ORDER) \
228 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
229 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
230 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
232 /* return minimum truesize of one skb containing X bytes of data */
233 #define SKB_TRUESIZE(X) ((X) + \
234 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
235 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
239 struct pipe_inode_info;
243 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
244 struct nf_conntrack {
249 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
250 struct nf_bridge_info {
253 BRNF_PROTO_UNCHANGED,
261 struct net_device *physindev;
263 /* always valid & non-NULL from FORWARD on, for physdev match */
264 struct net_device *physoutdev;
266 /* prerouting: detect dnat in orig/reply direction */
268 struct in6_addr ipv6_daddr;
270 /* after prerouting + nat detected: store original source
271 * mac since neigh resolution overwrites it, only used while
272 * skb is out in neigh layer.
274 char neigh_header[8];
279 struct sk_buff_head {
280 /* These two members must be first. */
281 struct sk_buff *next;
282 struct sk_buff *prev;
290 /* To allow 64K frame to be packed as single skb without frag_list we
291 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
292 * buffers which do not start on a page boundary.
294 * Since GRO uses frags we allocate at least 16 regardless of page
297 #if (65536/PAGE_SIZE + 1) < 16
298 #define MAX_SKB_FRAGS 16UL
300 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
302 extern int sysctl_max_skb_frags;
304 typedef struct skb_frag_struct skb_frag_t;
306 struct skb_frag_struct {
310 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
319 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
324 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
329 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
334 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
339 #define HAVE_HW_TIME_STAMP
342 * struct skb_shared_hwtstamps - hardware time stamps
343 * @hwtstamp: hardware time stamp transformed into duration
344 * since arbitrary point in time
346 * Software time stamps generated by ktime_get_real() are stored in
349 * hwtstamps can only be compared against other hwtstamps from
352 * This structure is attached to packets as part of the
353 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
355 struct skb_shared_hwtstamps {
359 /* Definitions for tx_flags in struct skb_shared_info */
361 /* generate hardware time stamp */
362 SKBTX_HW_TSTAMP = 1 << 0,
364 /* generate software time stamp when queueing packet to NIC */
365 SKBTX_SW_TSTAMP = 1 << 1,
367 /* device driver is going to provide hardware time stamp */
368 SKBTX_IN_PROGRESS = 1 << 2,
370 /* device driver supports TX zero-copy buffers */
371 SKBTX_DEV_ZEROCOPY = 1 << 3,
373 /* generate wifi status information (where possible) */
374 SKBTX_WIFI_STATUS = 1 << 4,
376 /* This indicates at least one fragment might be overwritten
377 * (as in vmsplice(), sendfile() ...)
378 * If we need to compute a TX checksum, we'll need to copy
379 * all frags to avoid possible bad checksum
381 SKBTX_SHARED_FRAG = 1 << 5,
383 /* generate software time stamp when entering packet scheduling */
384 SKBTX_SCHED_TSTAMP = 1 << 6,
386 /* generate software timestamp on peer data acknowledgment */
387 SKBTX_ACK_TSTAMP = 1 << 7,
390 #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
391 SKBTX_SCHED_TSTAMP | \
393 #define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
396 * The callback notifies userspace to release buffers when skb DMA is done in
397 * lower device, the skb last reference should be 0 when calling this.
398 * The zerocopy_success argument is true if zero copy transmit occurred,
399 * false on data copy or out of memory error caused by data copy attempt.
400 * The ctx field is used to track device context.
401 * The desc field is used to track userspace buffer index.
404 void (*callback)(struct ubuf_info *, bool zerocopy_success);
409 /* This data is invariant across clones and lives at
410 * the end of the header data, ie. at skb->end.
412 struct skb_shared_info {
413 unsigned char nr_frags;
415 unsigned short gso_size;
416 /* Warning: this field is not always filled in (UFO)! */
417 unsigned short gso_segs;
418 unsigned short gso_type;
419 struct sk_buff *frag_list;
420 struct skb_shared_hwtstamps hwtstamps;
425 * Warning : all fields before dataref are cleared in __alloc_skb()
429 /* Intermediate layers must ensure that destructor_arg
430 * remains valid until skb destructor */
431 void * destructor_arg;
433 /* must be last field, see pskb_expand_head() */
434 skb_frag_t frags[MAX_SKB_FRAGS];
437 /* We divide dataref into two halves. The higher 16 bits hold references
438 * to the payload part of skb->data. The lower 16 bits hold references to
439 * the entire skb->data. A clone of a headerless skb holds the length of
440 * the header in skb->hdr_len.
442 * All users must obey the rule that the skb->data reference count must be
443 * greater than or equal to the payload reference count.
445 * Holding a reference to the payload part means that the user does not
446 * care about modifications to the header part of skb->data.
448 #define SKB_DATAREF_SHIFT 16
449 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
453 SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
454 SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */
455 SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */
459 SKB_GSO_TCPV4 = 1 << 0,
460 SKB_GSO_UDP = 1 << 1,
462 /* This indicates the skb is from an untrusted source. */
463 SKB_GSO_DODGY = 1 << 2,
465 /* This indicates the tcp segment has CWR set. */
466 SKB_GSO_TCP_ECN = 1 << 3,
468 SKB_GSO_TCPV6 = 1 << 4,
470 SKB_GSO_FCOE = 1 << 5,
472 SKB_GSO_GRE = 1 << 6,
474 SKB_GSO_GRE_CSUM = 1 << 7,
476 SKB_GSO_IPIP = 1 << 8,
478 SKB_GSO_SIT = 1 << 9,
480 SKB_GSO_UDP_TUNNEL = 1 << 10,
482 SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
484 SKB_GSO_TUNNEL_REMCSUM = 1 << 12,
487 #if BITS_PER_LONG > 32
488 #define NET_SKBUFF_DATA_USES_OFFSET 1
491 #ifdef NET_SKBUFF_DATA_USES_OFFSET
492 typedef unsigned int sk_buff_data_t;
494 typedef unsigned char *sk_buff_data_t;
498 * struct skb_mstamp - multi resolution time stamps
499 * @stamp_us: timestamp in us resolution
500 * @stamp_jiffies: timestamp in jiffies
513 * skb_mstamp_get - get current timestamp
514 * @cl: place to store timestamps
516 static inline void skb_mstamp_get(struct skb_mstamp *cl)
518 u64 val = local_clock();
520 do_div(val, NSEC_PER_USEC);
521 cl->stamp_us = (u32)val;
522 cl->stamp_jiffies = (u32)jiffies;
526 * skb_mstamp_delta - compute the difference in usec between two skb_mstamp
527 * @t1: pointer to newest sample
528 * @t0: pointer to oldest sample
530 static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
531 const struct skb_mstamp *t0)
533 s32 delta_us = t1->stamp_us - t0->stamp_us;
534 u32 delta_jiffies = t1->stamp_jiffies - t0->stamp_jiffies;
536 /* If delta_us is negative, this might be because interval is too big,
537 * or local_clock() drift is too big : fallback using jiffies.
540 delta_jiffies >= (INT_MAX / (USEC_PER_SEC / HZ)))
542 delta_us = jiffies_to_usecs(delta_jiffies);
547 static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
548 const struct skb_mstamp *t0)
550 s32 diff = t1->stamp_jiffies - t0->stamp_jiffies;
553 diff = t1->stamp_us - t0->stamp_us;
558 * struct sk_buff - socket buffer
559 * @next: Next buffer in list
560 * @prev: Previous buffer in list
561 * @tstamp: Time we arrived/left
562 * @rbnode: RB tree node, alternative to next/prev for netem/tcp
563 * @sk: Socket we are owned by
564 * @dev: Device we arrived on/are leaving by
565 * @cb: Control buffer. Free for use by every layer. Put private vars here
566 * @_skb_refdst: destination entry (with norefcount bit)
567 * @sp: the security path, used for xfrm
568 * @len: Length of actual data
569 * @data_len: Data length
570 * @mac_len: Length of link layer header
571 * @hdr_len: writable header length of cloned skb
572 * @csum: Checksum (must include start/offset pair)
573 * @csum_start: Offset from skb->head where checksumming should start
574 * @csum_offset: Offset from csum_start where checksum should be stored
575 * @priority: Packet queueing priority
576 * @ignore_df: allow local fragmentation
577 * @cloned: Head may be cloned (check refcnt to be sure)
578 * @ip_summed: Driver fed us an IP checksum
579 * @nohdr: Payload reference only, must not modify header
580 * @nfctinfo: Relationship of this skb to the connection
581 * @pkt_type: Packet class
582 * @fclone: skbuff clone status
583 * @ipvs_property: skbuff is owned by ipvs
584 * @peeked: this packet has been seen already, so stats have been
585 * done for it, don't do them again
586 * @nf_trace: netfilter packet trace flag
587 * @protocol: Packet protocol from driver
588 * @destructor: Destruct function
589 * @nfct: Associated connection, if any
590 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
591 * @skb_iif: ifindex of device we arrived on
592 * @tc_index: Traffic control index
593 * @tc_verd: traffic control verdict
594 * @hash: the packet hash
595 * @queue_mapping: Queue mapping for multiqueue devices
596 * @xmit_more: More SKBs are pending for this queue
597 * @ndisc_nodetype: router type (from link layer)
598 * @ooo_okay: allow the mapping of a socket to a queue to be changed
599 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport
601 * @sw_hash: indicates hash was computed in software stack
602 * @wifi_acked_valid: wifi_acked was set
603 * @wifi_acked: whether frame was acked on wifi or not
604 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
605 * @napi_id: id of the NAPI struct this skb came from
606 * @secmark: security marking
607 * @offload_fwd_mark: fwding offload mark
608 * @mark: Generic packet mark
609 * @vlan_proto: vlan encapsulation protocol
610 * @vlan_tci: vlan tag control information
611 * @inner_protocol: Protocol (encapsulation)
612 * @inner_transport_header: Inner transport layer header (encapsulation)
613 * @inner_network_header: Network layer header (encapsulation)
614 * @inner_mac_header: Link layer header (encapsulation)
615 * @transport_header: Transport layer header
616 * @network_header: Network layer header
617 * @mac_header: Link layer header
618 * @tail: Tail pointer
620 * @head: Head of buffer
621 * @data: Data head pointer
622 * @truesize: Buffer size
623 * @users: User count - see {datagram,tcp}.c
629 /* These two members must be first. */
630 struct sk_buff *next;
631 struct sk_buff *prev;
635 struct skb_mstamp skb_mstamp;
638 struct rb_node rbnode; /* used in netem & tcp stack */
641 struct net_device *dev;
644 * This is the control buffer. It is free to use for every
645 * layer. Please put your private variables there. If you
646 * want to keep them across layers you have to do a skb_clone()
647 * first. This is owned by whoever has the skb queued ATM.
649 char cb[48] __aligned(8);
651 unsigned long _skb_refdst;
652 void (*destructor)(struct sk_buff *skb);
656 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
657 struct nf_conntrack *nfct;
659 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
660 struct nf_bridge_info *nf_bridge;
667 /* Following fields are _not_ copied in __copy_skb_header()
668 * Note that queue_mapping is here mostly to fill a hole.
670 kmemcheck_bitfield_begin(flags1);
679 kmemcheck_bitfield_end(flags1);
681 /* fields enclosed in headers_start/headers_end are copied
682 * using a single memcpy() in __copy_skb_header()
685 __u32 headers_start[0];
688 /* if you move pkt_type around you also must adapt those constants */
689 #ifdef __BIG_ENDIAN_BITFIELD
690 #define PKT_TYPE_MAX (7 << 5)
692 #define PKT_TYPE_MAX 7
694 #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
696 __u8 __pkt_type_offset[0];
707 __u8 wifi_acked_valid:1;
711 /* Indicates the inner headers are valid in the skbuff. */
712 __u8 encapsulation:1;
713 __u8 encap_hdr_csum:1;
715 __u8 csum_complete_sw:1;
719 #ifdef CONFIG_IPV6_NDISC_NODETYPE
720 __u8 ndisc_nodetype:2;
722 __u8 ipvs_property:1;
723 __u8 inner_protocol_type:1;
724 __u8 remcsum_offload:1;
725 /* 3 or 5 bit hole */
727 #ifdef CONFIG_NET_SCHED
728 __u16 tc_index; /* traffic control index */
729 #ifdef CONFIG_NET_CLS_ACT
730 __u16 tc_verd; /* traffic control verdict */
746 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
748 unsigned int napi_id;
749 unsigned int sender_cpu;
753 #ifdef CONFIG_NETWORK_SECMARK
756 #ifdef CONFIG_NET_SWITCHDEV
757 __u32 offload_fwd_mark;
763 __u32 reserved_tailroom;
767 __be16 inner_protocol;
771 __u16 inner_transport_header;
772 __u16 inner_network_header;
773 __u16 inner_mac_header;
776 __u16 transport_header;
777 __u16 network_header;
781 __u32 headers_end[0];
784 /* These elements must be at the end, see alloc_skb() for details. */
789 unsigned int truesize;
795 * Handling routines are only of interest to the kernel
797 #include <linux/slab.h>
800 #define SKB_ALLOC_FCLONE 0x01
801 #define SKB_ALLOC_RX 0x02
802 #define SKB_ALLOC_NAPI 0x04
804 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
805 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
807 return unlikely(skb->pfmemalloc);
811 * skb might have a dst pointer attached, refcounted or not.
812 * _skb_refdst low order bit is set if refcount was _not_ taken
814 #define SKB_DST_NOREF 1UL
815 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
818 * skb_dst - returns skb dst_entry
821 * Returns skb dst_entry, regardless of reference taken or not.
823 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
825 /* If refdst was not refcounted, check we still are in a
826 * rcu_read_lock section
828 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
829 !rcu_read_lock_held() &&
830 !rcu_read_lock_bh_held());
831 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
835 * skb_dst_set - sets skb dst
839 * Sets skb dst, assuming a reference was taken on dst and should
840 * be released by skb_dst_drop()
842 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
844 skb->_skb_refdst = (unsigned long)dst;
848 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
852 * Sets skb dst, assuming a reference was not taken on dst.
853 * If dst entry is cached, we do not take reference and dst_release
854 * will be avoided by refdst_drop. If dst entry is not cached, we take
855 * reference, so that last dst_release can destroy the dst immediately.
857 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
859 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
860 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
864 * skb_dst_is_noref - Test if skb dst isn't refcounted
867 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
869 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
872 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
874 return (struct rtable *)skb_dst(skb);
877 void kfree_skb(struct sk_buff *skb);
878 void kfree_skb_list(struct sk_buff *segs);
879 void skb_tx_error(struct sk_buff *skb);
880 void consume_skb(struct sk_buff *skb);
881 void __kfree_skb(struct sk_buff *skb);
882 extern struct kmem_cache *skbuff_head_cache;
884 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
885 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
886 bool *fragstolen, int *delta_truesize);
888 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
890 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
891 struct sk_buff *build_skb(void *data, unsigned int frag_size);
892 static inline struct sk_buff *alloc_skb(unsigned int size,
895 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
898 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
899 unsigned long data_len,
904 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
905 struct sk_buff_fclones {
914 * skb_fclone_busy - check if fclone is busy
917 * Returns true if skb is a fast clone, and its clone is not freed.
918 * Some drivers call skb_orphan() in their ndo_start_xmit(),
919 * so we also check that this didnt happen.
921 static inline bool skb_fclone_busy(const struct sock *sk,
922 const struct sk_buff *skb)
924 const struct sk_buff_fclones *fclones;
926 fclones = container_of(skb, struct sk_buff_fclones, skb1);
928 return skb->fclone == SKB_FCLONE_ORIG &&
929 atomic_read(&fclones->fclone_ref) > 1 &&
930 fclones->skb2.sk == sk;
933 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
936 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
939 struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
940 static inline struct sk_buff *alloc_skb_head(gfp_t priority)
942 return __alloc_skb_head(priority, -1);
945 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
946 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
947 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
948 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
949 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
950 gfp_t gfp_mask, bool fclone);
951 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
954 return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
957 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
958 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
959 unsigned int headroom);
960 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
961 int newtailroom, gfp_t priority);
962 int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
963 int offset, int len);
964 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
966 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
967 int skb_pad(struct sk_buff *skb, int pad);
968 #define dev_kfree_skb(a) consume_skb(a)
970 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
971 int getfrag(void *from, char *to, int offset,
972 int len, int odd, struct sk_buff *skb),
973 void *from, int length);
975 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
976 int offset, size_t size);
978 struct skb_seq_state {
982 __u32 stepped_offset;
983 struct sk_buff *root_skb;
984 struct sk_buff *cur_skb;
988 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
989 unsigned int to, struct skb_seq_state *st);
990 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
991 struct skb_seq_state *st);
992 void skb_abort_seq_read(struct skb_seq_state *st);
994 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
995 unsigned int to, struct ts_config *config);
998 * Packet hash types specify the type of hash in skb_set_hash.
1000 * Hash types refer to the protocol layer addresses which are used to
1001 * construct a packet's hash. The hashes are used to differentiate or identify
1002 * flows of the protocol layer for the hash type. Hash types are either
1003 * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1005 * Properties of hashes:
1007 * 1) Two packets in different flows have different hash values
1008 * 2) Two packets in the same flow should have the same hash value
1010 * A hash at a higher layer is considered to be more specific. A driver should
1011 * set the most specific hash possible.
1013 * A driver cannot indicate a more specific hash than the layer at which a hash
1014 * was computed. For instance an L3 hash cannot be set as an L4 hash.
1016 * A driver may indicate a hash level which is less specific than the
1017 * actual layer the hash was computed on. For instance, a hash computed
1018 * at L4 may be considered an L3 hash. This should only be done if the
1019 * driver can't unambiguously determine that the HW computed the hash at
1020 * the higher layer. Note that the "should" in the second property above
1023 enum pkt_hash_types {
1024 PKT_HASH_TYPE_NONE, /* Undefined type */
1025 PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
1026 PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
1027 PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
1030 static inline void skb_clear_hash(struct sk_buff *skb)
1037 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1040 skb_clear_hash(skb);
1044 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1046 skb->l4_hash = is_l4;
1047 skb->sw_hash = is_sw;
1052 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1054 /* Used by drivers to set hash from HW */
1055 __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1059 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1061 __skb_set_hash(skb, hash, true, is_l4);
1064 void __skb_get_hash(struct sk_buff *skb);
1065 u32 skb_get_poff(const struct sk_buff *skb);
1066 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1067 const struct flow_keys *keys, int hlen);
1068 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1069 void *data, int hlen_proto);
1071 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1072 int thoff, u8 ip_proto)
1074 return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1077 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1078 const struct flow_dissector_key *key,
1079 unsigned int key_count);
1081 bool __skb_flow_dissect(const struct sk_buff *skb,
1082 struct flow_dissector *flow_dissector,
1083 void *target_container,
1084 void *data, __be16 proto, int nhoff, int hlen,
1085 unsigned int flags);
1087 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1088 struct flow_dissector *flow_dissector,
1089 void *target_container, unsigned int flags)
1091 return __skb_flow_dissect(skb, flow_dissector, target_container,
1092 NULL, 0, 0, 0, flags);
1095 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1096 struct flow_keys *flow,
1099 memset(flow, 0, sizeof(*flow));
1100 return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
1101 NULL, 0, 0, 0, flags);
1104 static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
1105 void *data, __be16 proto,
1106 int nhoff, int hlen,
1109 memset(flow, 0, sizeof(*flow));
1110 return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
1111 data, proto, nhoff, hlen, flags);
1114 static inline __u32 skb_get_hash(struct sk_buff *skb)
1116 if (!skb->l4_hash && !skb->sw_hash)
1117 __skb_get_hash(skb);
1122 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6);
1124 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1126 if (!skb->l4_hash && !skb->sw_hash) {
1127 struct flow_keys keys;
1128 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1130 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1136 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl);
1138 static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
1140 if (!skb->l4_hash && !skb->sw_hash) {
1141 struct flow_keys keys;
1142 __u32 hash = __get_hash_from_flowi4(fl4, &keys);
1144 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1150 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1152 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1157 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1159 to->hash = from->hash;
1160 to->sw_hash = from->sw_hash;
1161 to->l4_hash = from->l4_hash;
1164 static inline void skb_sender_cpu_clear(struct sk_buff *skb)
1168 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1169 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1171 return skb->head + skb->end;
1174 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1179 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1184 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1186 return skb->end - skb->head;
1191 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1193 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1195 return &skb_shinfo(skb)->hwtstamps;
1199 * skb_queue_empty - check if a queue is empty
1202 * Returns true if the queue is empty, false otherwise.
1204 static inline int skb_queue_empty(const struct sk_buff_head *list)
1206 return list->next == (const struct sk_buff *) list;
1210 * skb_queue_is_last - check if skb is the last entry in the queue
1214 * Returns true if @skb is the last buffer on the list.
1216 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1217 const struct sk_buff *skb)
1219 return skb->next == (const struct sk_buff *) list;
1223 * skb_queue_is_first - check if skb is the first entry in the queue
1227 * Returns true if @skb is the first buffer on the list.
1229 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1230 const struct sk_buff *skb)
1232 return skb->prev == (const struct sk_buff *) list;
1236 * skb_queue_next - return the next packet in the queue
1238 * @skb: current buffer
1240 * Return the next packet in @list after @skb. It is only valid to
1241 * call this if skb_queue_is_last() evaluates to false.
1243 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1244 const struct sk_buff *skb)
1246 /* This BUG_ON may seem severe, but if we just return then we
1247 * are going to dereference garbage.
1249 BUG_ON(skb_queue_is_last(list, skb));
1254 * skb_queue_prev - return the prev packet in the queue
1256 * @skb: current buffer
1258 * Return the prev packet in @list before @skb. It is only valid to
1259 * call this if skb_queue_is_first() evaluates to false.
1261 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1262 const struct sk_buff *skb)
1264 /* This BUG_ON may seem severe, but if we just return then we
1265 * are going to dereference garbage.
1267 BUG_ON(skb_queue_is_first(list, skb));
1272 * skb_get - reference buffer
1273 * @skb: buffer to reference
1275 * Makes another reference to a socket buffer and returns a pointer
1278 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1280 atomic_inc(&skb->users);
1285 * If users == 1, we are the only owner and are can avoid redundant
1290 * skb_cloned - is the buffer a clone
1291 * @skb: buffer to check
1293 * Returns true if the buffer was generated with skb_clone() and is
1294 * one of multiple shared copies of the buffer. Cloned buffers are
1295 * shared data so must not be written to under normal circumstances.
1297 static inline int skb_cloned(const struct sk_buff *skb)
1299 return skb->cloned &&
1300 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1303 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1305 might_sleep_if(gfpflags_allow_blocking(pri));
1307 if (skb_cloned(skb))
1308 return pskb_expand_head(skb, 0, 0, pri);
1314 * skb_header_cloned - is the header a clone
1315 * @skb: buffer to check
1317 * Returns true if modifying the header part of the buffer requires
1318 * the data to be copied.
1320 static inline int skb_header_cloned(const struct sk_buff *skb)
1327 dataref = atomic_read(&skb_shinfo(skb)->dataref);
1328 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1329 return dataref != 1;
1333 * skb_header_release - release reference to header
1334 * @skb: buffer to operate on
1336 * Drop a reference to the header part of the buffer. This is done
1337 * by acquiring a payload reference. You must not read from the header
1338 * part of skb->data after this.
1339 * Note : Check if you can use __skb_header_release() instead.
1341 static inline void skb_header_release(struct sk_buff *skb)
1345 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
1349 * __skb_header_release - release reference to header
1350 * @skb: buffer to operate on
1352 * Variant of skb_header_release() assuming skb is private to caller.
1353 * We can avoid one atomic operation.
1355 static inline void __skb_header_release(struct sk_buff *skb)
1358 atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1363 * skb_shared - is the buffer shared
1364 * @skb: buffer to check
1366 * Returns true if more than one person has a reference to this
1369 static inline int skb_shared(const struct sk_buff *skb)
1371 return atomic_read(&skb->users) != 1;
1375 * skb_share_check - check if buffer is shared and if so clone it
1376 * @skb: buffer to check
1377 * @pri: priority for memory allocation
1379 * If the buffer is shared the buffer is cloned and the old copy
1380 * drops a reference. A new clone with a single reference is returned.
1381 * If the buffer is not shared the original buffer is returned. When
1382 * being called from interrupt status or with spinlocks held pri must
1385 * NULL is returned on a memory allocation failure.
1387 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1389 might_sleep_if(gfpflags_allow_blocking(pri));
1390 if (skb_shared(skb)) {
1391 struct sk_buff *nskb = skb_clone(skb, pri);
1403 * Copy shared buffers into a new sk_buff. We effectively do COW on
1404 * packets to handle cases where we have a local reader and forward
1405 * and a couple of other messy ones. The normal one is tcpdumping
1406 * a packet thats being forwarded.
1410 * skb_unshare - make a copy of a shared buffer
1411 * @skb: buffer to check
1412 * @pri: priority for memory allocation
1414 * If the socket buffer is a clone then this function creates a new
1415 * copy of the data, drops a reference count on the old copy and returns
1416 * the new copy with the reference count at 1. If the buffer is not a clone
1417 * the original buffer is returned. When called with a spinlock held or
1418 * from interrupt state @pri must be %GFP_ATOMIC
1420 * %NULL is returned on a memory allocation failure.
1422 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1425 might_sleep_if(gfpflags_allow_blocking(pri));
1426 if (skb_cloned(skb)) {
1427 struct sk_buff *nskb = skb_copy(skb, pri);
1429 /* Free our shared copy */
1440 * skb_peek - peek at the head of an &sk_buff_head
1441 * @list_: list to peek at
1443 * Peek an &sk_buff. Unlike most other operations you _MUST_
1444 * be careful with this one. A peek leaves the buffer on the
1445 * list and someone else may run off with it. You must hold
1446 * the appropriate locks or have a private queue to do this.
1448 * Returns %NULL for an empty list or a pointer to the head element.
1449 * The reference count is not incremented and the reference is therefore
1450 * volatile. Use with caution.
1452 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1454 struct sk_buff *skb = list_->next;
1456 if (skb == (struct sk_buff *)list_)
1462 * skb_peek_next - peek skb following the given one from a queue
1463 * @skb: skb to start from
1464 * @list_: list to peek at
1466 * Returns %NULL when the end of the list is met or a pointer to the
1467 * next element. The reference count is not incremented and the
1468 * reference is therefore volatile. Use with caution.
1470 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1471 const struct sk_buff_head *list_)
1473 struct sk_buff *next = skb->next;
1475 if (next == (struct sk_buff *)list_)
1481 * skb_peek_tail - peek at the tail of an &sk_buff_head
1482 * @list_: list to peek at
1484 * Peek an &sk_buff. Unlike most other operations you _MUST_
1485 * be careful with this one. A peek leaves the buffer on the
1486 * list and someone else may run off with it. You must hold
1487 * the appropriate locks or have a private queue to do this.
1489 * Returns %NULL for an empty list or a pointer to the tail element.
1490 * The reference count is not incremented and the reference is therefore
1491 * volatile. Use with caution.
1493 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1495 struct sk_buff *skb = list_->prev;
1497 if (skb == (struct sk_buff *)list_)
1504 * skb_queue_len - get queue length
1505 * @list_: list to measure
1507 * Return the length of an &sk_buff queue.
1509 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1515 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1516 * @list: queue to initialize
1518 * This initializes only the list and queue length aspects of
1519 * an sk_buff_head object. This allows to initialize the list
1520 * aspects of an sk_buff_head without reinitializing things like
1521 * the spinlock. It can also be used for on-stack sk_buff_head
1522 * objects where the spinlock is known to not be used.
1524 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1526 list->prev = list->next = (struct sk_buff *)list;
1531 * This function creates a split out lock class for each invocation;
1532 * this is needed for now since a whole lot of users of the skb-queue
1533 * infrastructure in drivers have different locking usage (in hardirq)
1534 * than the networking core (in softirq only). In the long run either the
1535 * network layer or drivers should need annotation to consolidate the
1536 * main types of usage into 3 classes.
1538 static inline void skb_queue_head_init(struct sk_buff_head *list)
1540 spin_lock_init(&list->lock);
1541 __skb_queue_head_init(list);
1544 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1545 struct lock_class_key *class)
1547 skb_queue_head_init(list);
1548 lockdep_set_class(&list->lock, class);
1552 * Insert an sk_buff on a list.
1554 * The "__skb_xxxx()" functions are the non-atomic ones that
1555 * can only be called with interrupts disabled.
1557 void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
1558 struct sk_buff_head *list);
1559 static inline void __skb_insert(struct sk_buff *newsk,
1560 struct sk_buff *prev, struct sk_buff *next,
1561 struct sk_buff_head *list)
1565 next->prev = prev->next = newsk;
1569 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1570 struct sk_buff *prev,
1571 struct sk_buff *next)
1573 struct sk_buff *first = list->next;
1574 struct sk_buff *last = list->prev;
1584 * skb_queue_splice - join two skb lists, this is designed for stacks
1585 * @list: the new list to add
1586 * @head: the place to add it in the first list
1588 static inline void skb_queue_splice(const struct sk_buff_head *list,
1589 struct sk_buff_head *head)
1591 if (!skb_queue_empty(list)) {
1592 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1593 head->qlen += list->qlen;
1598 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1599 * @list: the new list to add
1600 * @head: the place to add it in the first list
1602 * The list at @list is reinitialised
1604 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1605 struct sk_buff_head *head)
1607 if (!skb_queue_empty(list)) {
1608 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1609 head->qlen += list->qlen;
1610 __skb_queue_head_init(list);
1615 * skb_queue_splice_tail - join two skb lists, each list being a queue
1616 * @list: the new list to add
1617 * @head: the place to add it in the first list
1619 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1620 struct sk_buff_head *head)
1622 if (!skb_queue_empty(list)) {
1623 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1624 head->qlen += list->qlen;
1629 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1630 * @list: the new list to add
1631 * @head: the place to add it in the first list
1633 * Each of the lists is a queue.
1634 * The list at @list is reinitialised
1636 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1637 struct sk_buff_head *head)
1639 if (!skb_queue_empty(list)) {
1640 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1641 head->qlen += list->qlen;
1642 __skb_queue_head_init(list);
1647 * __skb_queue_after - queue a buffer at the list head
1648 * @list: list to use
1649 * @prev: place after this buffer
1650 * @newsk: buffer to queue
1652 * Queue a buffer int the middle of a list. This function takes no locks
1653 * and you must therefore hold required locks before calling it.
1655 * A buffer cannot be placed on two lists at the same time.
1657 static inline void __skb_queue_after(struct sk_buff_head *list,
1658 struct sk_buff *prev,
1659 struct sk_buff *newsk)
1661 __skb_insert(newsk, prev, prev->next, list);
1664 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1665 struct sk_buff_head *list);
1667 static inline void __skb_queue_before(struct sk_buff_head *list,
1668 struct sk_buff *next,
1669 struct sk_buff *newsk)
1671 __skb_insert(newsk, next->prev, next, list);
1675 * __skb_queue_head - queue a buffer at the list head
1676 * @list: list to use
1677 * @newsk: buffer to queue
1679 * Queue a buffer at the start of a list. This function takes no locks
1680 * and you must therefore hold required locks before calling it.
1682 * A buffer cannot be placed on two lists at the same time.
1684 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1685 static inline void __skb_queue_head(struct sk_buff_head *list,
1686 struct sk_buff *newsk)
1688 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1692 * __skb_queue_tail - queue a buffer at the list tail
1693 * @list: list to use
1694 * @newsk: buffer to queue
1696 * Queue a buffer at the end of a list. This function takes no locks
1697 * and you must therefore hold required locks before calling it.
1699 * A buffer cannot be placed on two lists at the same time.
1701 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1702 static inline void __skb_queue_tail(struct sk_buff_head *list,
1703 struct sk_buff *newsk)
1705 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1709 * remove sk_buff from list. _Must_ be called atomically, and with
1712 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1713 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1715 struct sk_buff *next, *prev;
1720 skb->next = skb->prev = NULL;
1726 * __skb_dequeue - remove from the head of the queue
1727 * @list: list to dequeue from
1729 * Remove the head of the list. This function does not take any locks
1730 * so must be used with appropriate locks held only. The head item is
1731 * returned or %NULL if the list is empty.
1733 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1734 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1736 struct sk_buff *skb = skb_peek(list);
1738 __skb_unlink(skb, list);
1743 * __skb_dequeue_tail - remove from the tail of the queue
1744 * @list: list to dequeue from
1746 * Remove the tail of the list. This function does not take any locks
1747 * so must be used with appropriate locks held only. The tail item is
1748 * returned or %NULL if the list is empty.
1750 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1751 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1753 struct sk_buff *skb = skb_peek_tail(list);
1755 __skb_unlink(skb, list);
1760 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1762 return skb->data_len;
1765 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1767 return skb->len - skb->data_len;
1770 static inline int skb_pagelen(const struct sk_buff *skb)
1774 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1775 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1776 return len + skb_headlen(skb);
1780 * __skb_fill_page_desc - initialise a paged fragment in an skb
1781 * @skb: buffer containing fragment to be initialised
1782 * @i: paged fragment index to initialise
1783 * @page: the page to use for this fragment
1784 * @off: the offset to the data with @page
1785 * @size: the length of the data
1787 * Initialises the @i'th fragment of @skb to point to &size bytes at
1788 * offset @off within @page.
1790 * Does not take any additional reference on the fragment.
1792 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1793 struct page *page, int off, int size)
1795 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1798 * Propagate page pfmemalloc to the skb if we can. The problem is
1799 * that not all callers have unique ownership of the page but rely
1800 * on page_is_pfmemalloc doing the right thing(tm).
1802 frag->page.p = page;
1803 frag->page_offset = off;
1804 skb_frag_size_set(frag, size);
1806 page = compound_head(page);
1807 if (page_is_pfmemalloc(page))
1808 skb->pfmemalloc = true;
1812 * skb_fill_page_desc - initialise a paged fragment in an skb
1813 * @skb: buffer containing fragment to be initialised
1814 * @i: paged fragment index to initialise
1815 * @page: the page to use for this fragment
1816 * @off: the offset to the data with @page
1817 * @size: the length of the data
1819 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1820 * @skb to point to @size bytes at offset @off within @page. In
1821 * addition updates @skb such that @i is the last fragment.
1823 * Does not take any additional reference on the fragment.
1825 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1826 struct page *page, int off, int size)
1828 __skb_fill_page_desc(skb, i, page, off, size);
1829 skb_shinfo(skb)->nr_frags = i + 1;
1832 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
1833 int size, unsigned int truesize);
1835 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
1836 unsigned int truesize);
1838 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1839 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1840 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1842 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1843 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1845 return skb->head + skb->tail;
1848 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1850 skb->tail = skb->data - skb->head;
1853 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1855 skb_reset_tail_pointer(skb);
1856 skb->tail += offset;
1859 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1860 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1865 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1867 skb->tail = skb->data;
1870 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1872 skb->tail = skb->data + offset;
1875 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1878 * Add data to an sk_buff
1880 unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
1881 unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1882 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1884 unsigned char *tmp = skb_tail_pointer(skb);
1885 SKB_LINEAR_ASSERT(skb);
1891 unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1892 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1899 unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1900 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1903 BUG_ON(skb->len < skb->data_len);
1904 return skb->data += len;
1907 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1909 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1912 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1914 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1916 if (len > skb_headlen(skb) &&
1917 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1920 return skb->data += len;
1923 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1925 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1928 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1930 if (likely(len <= skb_headlen(skb)))
1932 if (unlikely(len > skb->len))
1934 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1938 * skb_headroom - bytes at buffer head
1939 * @skb: buffer to check
1941 * Return the number of bytes of free space at the head of an &sk_buff.
1943 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1945 return skb->data - skb->head;
1949 * skb_tailroom - bytes at buffer end
1950 * @skb: buffer to check
1952 * Return the number of bytes of free space at the tail of an sk_buff
1954 static inline int skb_tailroom(const struct sk_buff *skb)
1956 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1960 * skb_availroom - bytes at buffer end
1961 * @skb: buffer to check
1963 * Return the number of bytes of free space at the tail of an sk_buff
1964 * allocated by sk_stream_alloc()
1966 static inline int skb_availroom(const struct sk_buff *skb)
1968 if (skb_is_nonlinear(skb))
1971 return skb->end - skb->tail - skb->reserved_tailroom;
1975 * skb_reserve - adjust headroom
1976 * @skb: buffer to alter
1977 * @len: bytes to move
1979 * Increase the headroom of an empty &sk_buff by reducing the tail
1980 * room. This is only allowed for an empty buffer.
1982 static inline void skb_reserve(struct sk_buff *skb, int len)
1988 #define ENCAP_TYPE_ETHER 0
1989 #define ENCAP_TYPE_IPPROTO 1
1991 static inline void skb_set_inner_protocol(struct sk_buff *skb,
1994 skb->inner_protocol = protocol;
1995 skb->inner_protocol_type = ENCAP_TYPE_ETHER;
1998 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2001 skb->inner_ipproto = ipproto;
2002 skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2005 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2007 skb->inner_mac_header = skb->mac_header;
2008 skb->inner_network_header = skb->network_header;
2009 skb->inner_transport_header = skb->transport_header;
2012 static inline void skb_reset_mac_len(struct sk_buff *skb)
2014 skb->mac_len = skb->network_header - skb->mac_header;
2017 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2020 return skb->head + skb->inner_transport_header;
2023 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2025 return skb_inner_transport_header(skb) - skb->data;
2028 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2030 skb->inner_transport_header = skb->data - skb->head;
2033 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2036 skb_reset_inner_transport_header(skb);
2037 skb->inner_transport_header += offset;
2040 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2042 return skb->head + skb->inner_network_header;
2045 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2047 skb->inner_network_header = skb->data - skb->head;
2050 static inline void skb_set_inner_network_header(struct sk_buff *skb,
2053 skb_reset_inner_network_header(skb);
2054 skb->inner_network_header += offset;
2057 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2059 return skb->head + skb->inner_mac_header;
2062 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2064 skb->inner_mac_header = skb->data - skb->head;
2067 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2070 skb_reset_inner_mac_header(skb);
2071 skb->inner_mac_header += offset;
2073 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2075 return skb->transport_header != (typeof(skb->transport_header))~0U;
2078 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2080 return skb->head + skb->transport_header;
2083 static inline void skb_reset_transport_header(struct sk_buff *skb)
2085 skb->transport_header = skb->data - skb->head;
2088 static inline void skb_set_transport_header(struct sk_buff *skb,
2091 skb_reset_transport_header(skb);
2092 skb->transport_header += offset;
2095 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2097 return skb->head + skb->network_header;
2100 static inline void skb_reset_network_header(struct sk_buff *skb)
2102 skb->network_header = skb->data - skb->head;
2105 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2107 skb_reset_network_header(skb);
2108 skb->network_header += offset;
2111 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2113 return skb->head + skb->mac_header;
2116 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2118 return skb->mac_header != (typeof(skb->mac_header))~0U;
2121 static inline void skb_reset_mac_header(struct sk_buff *skb)
2123 skb->mac_header = skb->data - skb->head;
2126 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2128 skb_reset_mac_header(skb);
2129 skb->mac_header += offset;
2132 static inline void skb_pop_mac_header(struct sk_buff *skb)
2134 skb->mac_header = skb->network_header;
2137 static inline void skb_probe_transport_header(struct sk_buff *skb,
2138 const int offset_hint)
2140 struct flow_keys keys;
2142 if (skb_transport_header_was_set(skb))
2144 else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
2145 skb_set_transport_header(skb, keys.control.thoff);
2147 skb_set_transport_header(skb, offset_hint);
2150 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2152 if (skb_mac_header_was_set(skb)) {
2153 const unsigned char *old_mac = skb_mac_header(skb);
2155 skb_set_mac_header(skb, -skb->mac_len);
2156 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2160 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2162 return skb->csum_start - skb_headroom(skb);
2165 static inline int skb_transport_offset(const struct sk_buff *skb)
2167 return skb_transport_header(skb) - skb->data;
2170 static inline u32 skb_network_header_len(const struct sk_buff *skb)
2172 return skb->transport_header - skb->network_header;
2175 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2177 return skb->inner_transport_header - skb->inner_network_header;
2180 static inline int skb_network_offset(const struct sk_buff *skb)
2182 return skb_network_header(skb) - skb->data;
2185 static inline int skb_inner_network_offset(const struct sk_buff *skb)
2187 return skb_inner_network_header(skb) - skb->data;
2190 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2192 return pskb_may_pull(skb, skb_network_offset(skb) + len);
2196 * CPUs often take a performance hit when accessing unaligned memory
2197 * locations. The actual performance hit varies, it can be small if the
2198 * hardware handles it or large if we have to take an exception and fix it
2201 * Since an ethernet header is 14 bytes network drivers often end up with
2202 * the IP header at an unaligned offset. The IP header can be aligned by
2203 * shifting the start of the packet by 2 bytes. Drivers should do this
2206 * skb_reserve(skb, NET_IP_ALIGN);
2208 * The downside to this alignment of the IP header is that the DMA is now
2209 * unaligned. On some architectures the cost of an unaligned DMA is high
2210 * and this cost outweighs the gains made by aligning the IP header.
2212 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2215 #ifndef NET_IP_ALIGN
2216 #define NET_IP_ALIGN 2
2220 * The networking layer reserves some headroom in skb data (via
2221 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2222 * the header has to grow. In the default case, if the header has to grow
2223 * 32 bytes or less we avoid the reallocation.
2225 * Unfortunately this headroom changes the DMA alignment of the resulting
2226 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2227 * on some architectures. An architecture can override this value,
2228 * perhaps setting it to a cacheline in size (since that will maintain
2229 * cacheline alignment of the DMA). It must be a power of 2.
2231 * Various parts of the networking layer expect at least 32 bytes of
2232 * headroom, you should not reduce this.
2234 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2235 * to reduce average number of cache lines per packet.
2236 * get_rps_cpus() for example only access one 64 bytes aligned block :
2237 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2240 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
2243 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2245 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2247 if (unlikely(skb_is_nonlinear(skb))) {
2252 skb_set_tail_pointer(skb, len);
2255 void skb_trim(struct sk_buff *skb, unsigned int len);
2257 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2260 return ___pskb_trim(skb, len);
2261 __skb_trim(skb, len);
2265 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2267 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2271 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2272 * @skb: buffer to alter
2275 * This is identical to pskb_trim except that the caller knows that
2276 * the skb is not cloned so we should never get an error due to out-
2279 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2281 int err = pskb_trim(skb, len);
2286 * skb_orphan - orphan a buffer
2287 * @skb: buffer to orphan
2289 * If a buffer currently has an owner then we call the owner's
2290 * destructor function and make the @skb unowned. The buffer continues
2291 * to exist but is no longer charged to its former owner.
2293 static inline void skb_orphan(struct sk_buff *skb)
2295 if (skb->destructor) {
2296 skb->destructor(skb);
2297 skb->destructor = NULL;
2305 * skb_orphan_frags - orphan the frags contained in a buffer
2306 * @skb: buffer to orphan frags from
2307 * @gfp_mask: allocation mask for replacement pages
2309 * For each frag in the SKB which needs a destructor (i.e. has an
2310 * owner) create a copy of that frag and release the original
2311 * page by calling the destructor.
2313 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2315 if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
2317 return skb_copy_ubufs(skb, gfp_mask);
2321 * __skb_queue_purge - empty a list
2322 * @list: list to empty
2324 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2325 * the list and one reference dropped. This function does not take the
2326 * list lock and the caller must hold the relevant locks to use it.
2328 void skb_queue_purge(struct sk_buff_head *list);
2329 static inline void __skb_queue_purge(struct sk_buff_head *list)
2331 struct sk_buff *skb;
2332 while ((skb = __skb_dequeue(list)) != NULL)
2336 void *netdev_alloc_frag(unsigned int fragsz);
2338 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2342 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
2343 * @dev: network device to receive on
2344 * @length: length to allocate
2346 * Allocate a new &sk_buff and assign it a usage count of one. The
2347 * buffer has unspecified headroom built in. Users should allocate
2348 * the headroom they think they need without accounting for the
2349 * built in space. The built in space is used for optimisations.
2351 * %NULL is returned if there is no free memory. Although this function
2352 * allocates memory it can be called from an interrupt.
2354 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2355 unsigned int length)
2357 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2360 /* legacy helper around __netdev_alloc_skb() */
2361 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2364 return __netdev_alloc_skb(NULL, length, gfp_mask);
2367 /* legacy helper around netdev_alloc_skb() */
2368 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2370 return netdev_alloc_skb(NULL, length);
2374 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2375 unsigned int length, gfp_t gfp)
2377 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2379 if (NET_IP_ALIGN && skb)
2380 skb_reserve(skb, NET_IP_ALIGN);
2384 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2385 unsigned int length)
2387 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2390 static inline void skb_free_frag(void *addr)
2392 __free_page_frag(addr);
2395 void *napi_alloc_frag(unsigned int fragsz);
2396 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2397 unsigned int length, gfp_t gfp_mask);
2398 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2399 unsigned int length)
2401 return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2405 * __dev_alloc_pages - allocate page for network Rx
2406 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2407 * @order: size of the allocation
2409 * Allocate a new page.
2411 * %NULL is returned if there is no free memory.
2413 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2416 /* This piece of code contains several assumptions.
2417 * 1. This is for device Rx, therefor a cold page is preferred.
2418 * 2. The expectation is the user wants a compound page.
2419 * 3. If requesting a order 0 page it will not be compound
2420 * due to the check to see if order has a value in prep_new_page
2421 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2422 * code in gfp_to_alloc_flags that should be enforcing this.
2424 gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC;
2426 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2429 static inline struct page *dev_alloc_pages(unsigned int order)
2431 return __dev_alloc_pages(GFP_ATOMIC, order);
2435 * __dev_alloc_page - allocate a page for network Rx
2436 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2438 * Allocate a new page.
2440 * %NULL is returned if there is no free memory.
2442 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2444 return __dev_alloc_pages(gfp_mask, 0);
2447 static inline struct page *dev_alloc_page(void)
2449 return __dev_alloc_page(GFP_ATOMIC);
2453 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2454 * @page: The page that was allocated from skb_alloc_page
2455 * @skb: The skb that may need pfmemalloc set
2457 static inline void skb_propagate_pfmemalloc(struct page *page,
2458 struct sk_buff *skb)
2460 if (page_is_pfmemalloc(page))
2461 skb->pfmemalloc = true;
2465 * skb_frag_page - retrieve the page referred to by a paged fragment
2466 * @frag: the paged fragment
2468 * Returns the &struct page associated with @frag.
2470 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2472 return frag->page.p;
2476 * __skb_frag_ref - take an addition reference on a paged fragment.
2477 * @frag: the paged fragment
2479 * Takes an additional reference on the paged fragment @frag.
2481 static inline void __skb_frag_ref(skb_frag_t *frag)
2483 get_page(skb_frag_page(frag));
2487 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2489 * @f: the fragment offset.
2491 * Takes an additional reference on the @f'th paged fragment of @skb.
2493 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2495 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2499 * __skb_frag_unref - release a reference on a paged fragment.
2500 * @frag: the paged fragment
2502 * Releases a reference on the paged fragment @frag.
2504 static inline void __skb_frag_unref(skb_frag_t *frag)
2506 put_page(skb_frag_page(frag));
2510 * skb_frag_unref - release a reference on a paged fragment of an skb.
2512 * @f: the fragment offset
2514 * Releases a reference on the @f'th paged fragment of @skb.
2516 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2518 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2522 * skb_frag_address - gets the address of the data contained in a paged fragment
2523 * @frag: the paged fragment buffer
2525 * Returns the address of the data within @frag. The page must already
2528 static inline void *skb_frag_address(const skb_frag_t *frag)
2530 return page_address(skb_frag_page(frag)) + frag->page_offset;
2534 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2535 * @frag: the paged fragment buffer
2537 * Returns the address of the data within @frag. Checks that the page
2538 * is mapped and returns %NULL otherwise.
2540 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2542 void *ptr = page_address(skb_frag_page(frag));
2546 return ptr + frag->page_offset;
2550 * __skb_frag_set_page - sets the page contained in a paged fragment
2551 * @frag: the paged fragment
2552 * @page: the page to set
2554 * Sets the fragment @frag to contain @page.
2556 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2558 frag->page.p = page;
2562 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2564 * @f: the fragment offset
2565 * @page: the page to set
2567 * Sets the @f'th fragment of @skb to contain @page.
2569 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2572 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2575 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2578 * skb_frag_dma_map - maps a paged fragment via the DMA API
2579 * @dev: the device to map the fragment to
2580 * @frag: the paged fragment to map
2581 * @offset: the offset within the fragment (starting at the
2582 * fragment's own offset)
2583 * @size: the number of bytes to map
2584 * @dir: the direction of the mapping (%PCI_DMA_*)
2586 * Maps the page associated with @frag to @device.
2588 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2589 const skb_frag_t *frag,
2590 size_t offset, size_t size,
2591 enum dma_data_direction dir)
2593 return dma_map_page(dev, skb_frag_page(frag),
2594 frag->page_offset + offset, size, dir);
2597 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2600 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2604 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
2607 return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
2612 * skb_clone_writable - is the header of a clone writable
2613 * @skb: buffer to check
2614 * @len: length up to which to write
2616 * Returns true if modifying the header part of the cloned buffer
2617 * does not requires the data to be copied.
2619 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2621 return !skb_header_cloned(skb) &&
2622 skb_headroom(skb) + len <= skb->hdr_len;
2625 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2630 if (headroom > skb_headroom(skb))
2631 delta = headroom - skb_headroom(skb);
2633 if (delta || cloned)
2634 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2640 * skb_cow - copy header of skb when it is required
2641 * @skb: buffer to cow
2642 * @headroom: needed headroom
2644 * If the skb passed lacks sufficient headroom or its data part
2645 * is shared, data is reallocated. If reallocation fails, an error
2646 * is returned and original skb is not changed.
2648 * The result is skb with writable area skb->head...skb->tail
2649 * and at least @headroom of space at head.
2651 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2653 return __skb_cow(skb, headroom, skb_cloned(skb));
2657 * skb_cow_head - skb_cow but only making the head writable
2658 * @skb: buffer to cow
2659 * @headroom: needed headroom
2661 * This function is identical to skb_cow except that we replace the
2662 * skb_cloned check by skb_header_cloned. It should be used when
2663 * you only need to push on some header and do not need to modify
2666 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2668 return __skb_cow(skb, headroom, skb_header_cloned(skb));
2672 * skb_padto - pad an skbuff up to a minimal size
2673 * @skb: buffer to pad
2674 * @len: minimal length
2676 * Pads up a buffer to ensure the trailing bytes exist and are
2677 * blanked. If the buffer already contains sufficient data it
2678 * is untouched. Otherwise it is extended. Returns zero on
2679 * success. The skb is freed on error.
2681 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2683 unsigned int size = skb->len;
2684 if (likely(size >= len))
2686 return skb_pad(skb, len - size);
2690 * skb_put_padto - increase size and pad an skbuff up to a minimal size
2691 * @skb: buffer to pad
2692 * @len: minimal length
2694 * Pads up a buffer to ensure the trailing bytes exist and are
2695 * blanked. If the buffer already contains sufficient data it
2696 * is untouched. Otherwise it is extended. Returns zero on
2697 * success. The skb is freed on error.
2699 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
2701 unsigned int size = skb->len;
2703 if (unlikely(size < len)) {
2705 if (skb_pad(skb, len))
2707 __skb_put(skb, len);
2712 static inline int skb_add_data(struct sk_buff *skb,
2713 struct iov_iter *from, int copy)
2715 const int off = skb->len;
2717 if (skb->ip_summed == CHECKSUM_NONE) {
2719 if (csum_and_copy_from_iter(skb_put(skb, copy), copy,
2720 &csum, from) == copy) {
2721 skb->csum = csum_block_add(skb->csum, csum, off);
2724 } else if (copy_from_iter(skb_put(skb, copy), copy, from) == copy)
2727 __skb_trim(skb, off);
2731 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2732 const struct page *page, int off)
2735 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2737 return page == skb_frag_page(frag) &&
2738 off == frag->page_offset + skb_frag_size(frag);
2743 static inline int __skb_linearize(struct sk_buff *skb)
2745 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2749 * skb_linearize - convert paged skb to linear one
2750 * @skb: buffer to linarize
2752 * If there is no free memory -ENOMEM is returned, otherwise zero
2753 * is returned and the old skb data released.
2755 static inline int skb_linearize(struct sk_buff *skb)
2757 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2761 * skb_has_shared_frag - can any frag be overwritten
2762 * @skb: buffer to test
2764 * Return true if the skb has at least one frag that might be modified
2765 * by an external entity (as in vmsplice()/sendfile())
2767 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2769 return skb_is_nonlinear(skb) &&
2770 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2774 * skb_linearize_cow - make sure skb is linear and writable
2775 * @skb: buffer to process
2777 * If there is no free memory -ENOMEM is returned, otherwise zero
2778 * is returned and the old skb data released.
2780 static inline int skb_linearize_cow(struct sk_buff *skb)
2782 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2783 __skb_linearize(skb) : 0;
2787 * skb_postpull_rcsum - update checksum for received skb after pull
2788 * @skb: buffer to update
2789 * @start: start of data before pull
2790 * @len: length of data pulled
2792 * After doing a pull on a received packet, you need to call this to
2793 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2794 * CHECKSUM_NONE so that it can be recomputed from scratch.
2797 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2798 const void *start, unsigned int len)
2800 if (skb->ip_summed == CHECKSUM_COMPLETE)
2801 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
2802 else if (skb->ip_summed == CHECKSUM_PARTIAL &&
2803 skb_checksum_start_offset(skb) < 0)
2804 skb->ip_summed = CHECKSUM_NONE;
2807 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2809 static inline void skb_postpush_rcsum(struct sk_buff *skb,
2810 const void *start, unsigned int len)
2812 /* For performing the reverse operation to skb_postpull_rcsum(),
2813 * we can instead of ...
2815 * skb->csum = csum_add(skb->csum, csum_partial(start, len, 0));
2817 * ... just use this equivalent version here to save a few
2818 * instructions. Feeding csum of 0 in csum_partial() and later
2819 * on adding skb->csum is equivalent to feed skb->csum in the
2822 if (skb->ip_summed == CHECKSUM_COMPLETE)
2823 skb->csum = csum_partial(start, len, skb->csum);
2827 * pskb_trim_rcsum - trim received skb and update checksum
2828 * @skb: buffer to trim
2831 * This is exactly the same as pskb_trim except that it ensures the
2832 * checksum of received packets are still valid after the operation.
2835 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2837 if (likely(len >= skb->len))
2839 if (skb->ip_summed == CHECKSUM_COMPLETE)
2840 skb->ip_summed = CHECKSUM_NONE;
2841 return __pskb_trim(skb, len);
2844 #define skb_queue_walk(queue, skb) \
2845 for (skb = (queue)->next; \
2846 skb != (struct sk_buff *)(queue); \
2849 #define skb_queue_walk_safe(queue, skb, tmp) \
2850 for (skb = (queue)->next, tmp = skb->next; \
2851 skb != (struct sk_buff *)(queue); \
2852 skb = tmp, tmp = skb->next)
2854 #define skb_queue_walk_from(queue, skb) \
2855 for (; skb != (struct sk_buff *)(queue); \
2858 #define skb_queue_walk_from_safe(queue, skb, tmp) \
2859 for (tmp = skb->next; \
2860 skb != (struct sk_buff *)(queue); \
2861 skb = tmp, tmp = skb->next)
2863 #define skb_queue_reverse_walk(queue, skb) \
2864 for (skb = (queue)->prev; \
2865 skb != (struct sk_buff *)(queue); \
2868 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
2869 for (skb = (queue)->prev, tmp = skb->prev; \
2870 skb != (struct sk_buff *)(queue); \
2871 skb = tmp, tmp = skb->prev)
2873 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
2874 for (tmp = skb->prev; \
2875 skb != (struct sk_buff *)(queue); \
2876 skb = tmp, tmp = skb->prev)
2878 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2880 return skb_shinfo(skb)->frag_list != NULL;
2883 static inline void skb_frag_list_init(struct sk_buff *skb)
2885 skb_shinfo(skb)->frag_list = NULL;
2888 #define skb_walk_frags(skb, iter) \
2889 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2892 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
2893 const struct sk_buff *skb);
2894 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
2895 int *peeked, int *off, int *err,
2896 struct sk_buff **last);
2897 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2898 int *peeked, int *off, int *err);
2899 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
2901 unsigned int datagram_poll(struct file *file, struct socket *sock,
2902 struct poll_table_struct *wait);
2903 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
2904 struct iov_iter *to, int size);
2905 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
2906 struct msghdr *msg, int size)
2908 return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
2910 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
2911 struct msghdr *msg);
2912 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
2913 struct iov_iter *from, int len);
2914 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
2915 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2916 void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);
2917 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
2918 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
2919 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
2920 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
2921 int len, __wsum csum);
2922 ssize_t skb_socket_splice(struct sock *sk,
2923 struct pipe_inode_info *pipe,
2924 struct splice_pipe_desc *spd);
2925 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
2926 struct pipe_inode_info *pipe, unsigned int len,
2928 ssize_t (*splice_cb)(struct sock *,
2929 struct pipe_inode_info *,
2930 struct splice_pipe_desc *));
2931 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2932 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
2933 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
2935 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
2936 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
2937 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
2938 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
2939 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
2940 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
2941 int skb_ensure_writable(struct sk_buff *skb, int write_len);
2942 int skb_vlan_pop(struct sk_buff *skb);
2943 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
2945 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
2947 return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
2950 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
2952 return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
2955 struct skb_checksum_ops {
2956 __wsum (*update)(const void *mem, int len, __wsum wsum);
2957 __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
2960 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2961 __wsum csum, const struct skb_checksum_ops *ops);
2962 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
2965 static inline void * __must_check
2966 __skb_header_pointer(const struct sk_buff *skb, int offset,
2967 int len, void *data, int hlen, void *buffer)
2969 if (hlen - offset >= len)
2970 return data + offset;
2973 skb_copy_bits(skb, offset, buffer, len) < 0)
2979 static inline void * __must_check
2980 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
2982 return __skb_header_pointer(skb, offset, len, skb->data,
2983 skb_headlen(skb), buffer);
2987 * skb_needs_linearize - check if we need to linearize a given skb
2988 * depending on the given device features.
2989 * @skb: socket buffer to check
2990 * @features: net device features
2992 * Returns true if either:
2993 * 1. skb has frag_list and the device doesn't support FRAGLIST, or
2994 * 2. skb is fragmented and the device does not support SG.
2996 static inline bool skb_needs_linearize(struct sk_buff *skb,
2997 netdev_features_t features)
2999 return skb_is_nonlinear(skb) &&
3000 ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3001 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3004 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3006 const unsigned int len)
3008 memcpy(to, skb->data, len);
3011 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3012 const int offset, void *to,
3013 const unsigned int len)
3015 memcpy(to, skb->data + offset, len);
3018 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3020 const unsigned int len)
3022 memcpy(skb->data, from, len);
3025 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3028 const unsigned int len)
3030 memcpy(skb->data + offset, from, len);
3033 void skb_init(void);
3035 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3041 * skb_get_timestamp - get timestamp from a skb
3042 * @skb: skb to get stamp from
3043 * @stamp: pointer to struct timeval to store stamp in
3045 * Timestamps are stored in the skb as offsets to a base timestamp.
3046 * This function converts the offset back to a struct timeval and stores
3049 static inline void skb_get_timestamp(const struct sk_buff *skb,
3050 struct timeval *stamp)
3052 *stamp = ktime_to_timeval(skb->tstamp);
3055 static inline void skb_get_timestampns(const struct sk_buff *skb,
3056 struct timespec *stamp)
3058 *stamp = ktime_to_timespec(skb->tstamp);
3061 static inline void __net_timestamp(struct sk_buff *skb)
3063 skb->tstamp = ktime_get_real();
3066 static inline ktime_t net_timedelta(ktime_t t)
3068 return ktime_sub(ktime_get_real(), t);
3071 static inline ktime_t net_invalid_timestamp(void)
3073 return ktime_set(0, 0);
3076 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3078 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3080 void skb_clone_tx_timestamp(struct sk_buff *skb);
3081 bool skb_defer_rx_timestamp(struct sk_buff *skb);
3083 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3085 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3089 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3094 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3097 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3099 * PHY drivers may accept clones of transmitted packets for
3100 * timestamping via their phy_driver.txtstamp method. These drivers
3101 * must call this function to return the skb back to the stack with a
3104 * @skb: clone of the the original outgoing packet
3105 * @hwtstamps: hardware time stamps
3108 void skb_complete_tx_timestamp(struct sk_buff *skb,
3109 struct skb_shared_hwtstamps *hwtstamps);
3111 void __skb_tstamp_tx(struct sk_buff *orig_skb,
3112 struct skb_shared_hwtstamps *hwtstamps,
3113 struct sock *sk, int tstype);
3116 * skb_tstamp_tx - queue clone of skb with send time stamps
3117 * @orig_skb: the original outgoing packet
3118 * @hwtstamps: hardware time stamps, may be NULL if not available
3120 * If the skb has a socket associated, then this function clones the
3121 * skb (thus sharing the actual data and optional structures), stores
3122 * the optional hardware time stamping information (if non NULL) or
3123 * generates a software time stamp (otherwise), then queues the clone
3124 * to the error queue of the socket. Errors are silently ignored.
3126 void skb_tstamp_tx(struct sk_buff *orig_skb,
3127 struct skb_shared_hwtstamps *hwtstamps);
3129 static inline void sw_tx_timestamp(struct sk_buff *skb)
3131 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
3132 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
3133 skb_tstamp_tx(skb, NULL);
3137 * skb_tx_timestamp() - Driver hook for transmit timestamping
3139 * Ethernet MAC Drivers should call this function in their hard_xmit()
3140 * function immediately before giving the sk_buff to the MAC hardware.
3142 * Specifically, one should make absolutely sure that this function is
3143 * called before TX completion of this packet can trigger. Otherwise
3144 * the packet could potentially already be freed.
3146 * @skb: A socket buffer.
3148 static inline void skb_tx_timestamp(struct sk_buff *skb)
3150 skb_clone_tx_timestamp(skb);
3151 sw_tx_timestamp(skb);
3155 * skb_complete_wifi_ack - deliver skb with wifi status
3157 * @skb: the original outgoing packet
3158 * @acked: ack status
3161 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3163 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3164 __sum16 __skb_checksum_complete(struct sk_buff *skb);
3166 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3168 return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3170 (skb->ip_summed == CHECKSUM_PARTIAL &&
3171 skb_checksum_start_offset(skb) >= 0));
3175 * skb_checksum_complete - Calculate checksum of an entire packet
3176 * @skb: packet to process
3178 * This function calculates the checksum over the entire packet plus
3179 * the value of skb->csum. The latter can be used to supply the
3180 * checksum of a pseudo header as used by TCP/UDP. It returns the
3183 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
3184 * this function can be used to verify that checksum on received
3185 * packets. In that case the function should return zero if the
3186 * checksum is correct. In particular, this function will return zero
3187 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3188 * hardware has already verified the correctness of the checksum.
3190 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3192 return skb_csum_unnecessary(skb) ?
3193 0 : __skb_checksum_complete(skb);
3196 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3198 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3199 if (skb->csum_level == 0)
3200 skb->ip_summed = CHECKSUM_NONE;
3206 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3208 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3209 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3211 } else if (skb->ip_summed == CHECKSUM_NONE) {
3212 skb->ip_summed = CHECKSUM_UNNECESSARY;
3213 skb->csum_level = 0;
3217 static inline void __skb_mark_checksum_bad(struct sk_buff *skb)
3219 /* Mark current checksum as bad (typically called from GRO
3220 * path). In the case that ip_summed is CHECKSUM_NONE
3221 * this must be the first checksum encountered in the packet.
3222 * When ip_summed is CHECKSUM_UNNECESSARY, this is the first
3223 * checksum after the last one validated. For UDP, a zero
3224 * checksum can not be marked as bad.
3227 if (skb->ip_summed == CHECKSUM_NONE ||
3228 skb->ip_summed == CHECKSUM_UNNECESSARY)
3232 /* Check if we need to perform checksum complete validation.
3234 * Returns true if checksum complete is needed, false otherwise
3235 * (either checksum is unnecessary or zero checksum is allowed).
3237 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3241 if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3242 skb->csum_valid = 1;
3243 __skb_decr_checksum_unnecessary(skb);
3250 /* For small packets <= CHECKSUM_BREAK peform checksum complete directly
3253 #define CHECKSUM_BREAK 76
3255 /* Unset checksum-complete
3257 * Unset checksum complete can be done when packet is being modified
3258 * (uncompressed for instance) and checksum-complete value is
3261 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3263 if (skb->ip_summed == CHECKSUM_COMPLETE)
3264 skb->ip_summed = CHECKSUM_NONE;
3267 /* Validate (init) checksum based on checksum complete.
3270 * 0: checksum is validated or try to in skb_checksum_complete. In the latter
3271 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3272 * checksum is stored in skb->csum for use in __skb_checksum_complete
3273 * non-zero: value of invalid checksum
3276 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3280 if (skb->ip_summed == CHECKSUM_COMPLETE) {
3281 if (!csum_fold(csum_add(psum, skb->csum))) {
3282 skb->csum_valid = 1;
3285 } else if (skb->csum_bad) {
3286 /* ip_summed == CHECKSUM_NONE in this case */
3287 return (__force __sum16)1;
3292 if (complete || skb->len <= CHECKSUM_BREAK) {
3295 csum = __skb_checksum_complete(skb);
3296 skb->csum_valid = !csum;
3303 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3308 /* Perform checksum validate (init). Note that this is a macro since we only
3309 * want to calculate the pseudo header which is an input function if necessary.
3310 * First we try to validate without any computation (checksum unnecessary) and
3311 * then calculate based on checksum complete calling the function to compute
3315 * 0: checksum is validated or try to in skb_checksum_complete
3316 * non-zero: value of invalid checksum
3318 #define __skb_checksum_validate(skb, proto, complete, \
3319 zero_okay, check, compute_pseudo) \
3321 __sum16 __ret = 0; \
3322 skb->csum_valid = 0; \
3323 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
3324 __ret = __skb_checksum_validate_complete(skb, \
3325 complete, compute_pseudo(skb, proto)); \
3329 #define skb_checksum_init(skb, proto, compute_pseudo) \
3330 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3332 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3333 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3335 #define skb_checksum_validate(skb, proto, compute_pseudo) \
3336 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3338 #define skb_checksum_validate_zero_check(skb, proto, check, \
3340 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3342 #define skb_checksum_simple_validate(skb) \
3343 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3345 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3347 return (skb->ip_summed == CHECKSUM_NONE &&
3348 skb->csum_valid && !skb->csum_bad);
3351 static inline void __skb_checksum_convert(struct sk_buff *skb,
3352 __sum16 check, __wsum pseudo)
3354 skb->csum = ~pseudo;
3355 skb->ip_summed = CHECKSUM_COMPLETE;
3358 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo) \
3360 if (__skb_checksum_convert_check(skb)) \
3361 __skb_checksum_convert(skb, check, \
3362 compute_pseudo(skb, proto)); \
3365 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3366 u16 start, u16 offset)
3368 skb->ip_summed = CHECKSUM_PARTIAL;
3369 skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3370 skb->csum_offset = offset - start;
3373 /* Update skbuf and packet to reflect the remote checksum offload operation.
3374 * When called, ptr indicates the starting point for skb->csum when
3375 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3376 * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3378 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3379 int start, int offset, bool nopartial)
3384 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3388 if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3389 __skb_checksum_complete(skb);
3390 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3393 delta = remcsum_adjust(ptr, skb->csum, start, offset);
3395 /* Adjust skb->csum since we changed the packet */
3396 skb->csum = csum_add(skb->csum, delta);
3399 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3400 void nf_conntrack_destroy(struct nf_conntrack *nfct);
3401 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3403 if (nfct && atomic_dec_and_test(&nfct->use))
3404 nf_conntrack_destroy(nfct);
3406 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3409 atomic_inc(&nfct->use);
3412 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3413 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
3415 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
3418 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
3421 atomic_inc(&nf_bridge->use);
3423 #endif /* CONFIG_BRIDGE_NETFILTER */
3424 static inline void nf_reset(struct sk_buff *skb)
3426 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3427 nf_conntrack_put(skb->nfct);
3430 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3431 nf_bridge_put(skb->nf_bridge);
3432 skb->nf_bridge = NULL;
3436 static inline void nf_reset_trace(struct sk_buff *skb)
3438 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3443 /* Note: This doesn't put any conntrack and bridge info in dst. */
3444 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
3447 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3448 dst->nfct = src->nfct;
3449 nf_conntrack_get(src->nfct);
3451 dst->nfctinfo = src->nfctinfo;
3453 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3454 dst->nf_bridge = src->nf_bridge;
3455 nf_bridge_get(src->nf_bridge);
3457 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3459 dst->nf_trace = src->nf_trace;
3463 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
3465 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3466 nf_conntrack_put(dst->nfct);
3468 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3469 nf_bridge_put(dst->nf_bridge);
3471 __nf_copy(dst, src, true);
3474 #ifdef CONFIG_NETWORK_SECMARK
3475 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3477 to->secmark = from->secmark;
3480 static inline void skb_init_secmark(struct sk_buff *skb)
3485 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3488 static inline void skb_init_secmark(struct sk_buff *skb)
3492 static inline bool skb_irq_freeable(const struct sk_buff *skb)
3494 return !skb->destructor &&
3495 #if IS_ENABLED(CONFIG_XFRM)
3498 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3501 !skb->_skb_refdst &&
3502 !skb_has_frag_list(skb);
3505 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
3507 skb->queue_mapping = queue_mapping;
3510 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
3512 return skb->queue_mapping;
3515 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
3517 to->queue_mapping = from->queue_mapping;
3520 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
3522 skb->queue_mapping = rx_queue + 1;
3525 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
3527 return skb->queue_mapping - 1;
3530 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
3532 return skb->queue_mapping != 0;
3535 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
3544 /* Keeps track of mac header offset relative to skb->head.
3545 * It is useful for TSO of Tunneling protocol. e.g. GRE.
3546 * For non-tunnel skb it points to skb_mac_header() and for
3547 * tunnel skb it points to outer mac header.
3548 * Keeps track of level of encapsulation of network headers.
3555 #define SKB_SGO_CB_OFFSET 32
3556 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
3558 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
3560 return (skb_mac_header(inner_skb) - inner_skb->head) -
3561 SKB_GSO_CB(inner_skb)->mac_offset;
3564 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
3566 int new_headroom, headroom;
3569 headroom = skb_headroom(skb);
3570 ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
3574 new_headroom = skb_headroom(skb);
3575 SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
3579 /* Compute the checksum for a gso segment. First compute the checksum value
3580 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
3581 * then add in skb->csum (checksum from csum_start to end of packet).
3582 * skb->csum and csum_start are then updated to reflect the checksum of the
3583 * resultant packet starting from the transport header-- the resultant checksum
3584 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
3587 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
3589 int plen = SKB_GSO_CB(skb)->csum_start - skb_headroom(skb) -
3590 skb_transport_offset(skb);
3593 partial = csum_partial(skb_transport_header(skb), plen, skb->csum);
3595 SKB_GSO_CB(skb)->csum_start -= plen;
3597 return csum_fold(partial);
3600 static inline bool skb_is_gso(const struct sk_buff *skb)
3602 return skb_shinfo(skb)->gso_size;
3605 /* Note: Should be called only if skb_is_gso(skb) is true */
3606 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
3608 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
3611 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
3613 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
3615 /* LRO sets gso_size but not gso_type, whereas if GSO is really
3616 * wanted then gso_type will be set. */
3617 const struct skb_shared_info *shinfo = skb_shinfo(skb);
3619 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
3620 unlikely(shinfo->gso_type == 0)) {
3621 __skb_warn_lro_forwarding(skb);
3627 static inline void skb_forward_csum(struct sk_buff *skb)
3629 /* Unfortunately we don't support this one. Any brave souls? */
3630 if (skb->ip_summed == CHECKSUM_COMPLETE)
3631 skb->ip_summed = CHECKSUM_NONE;
3635 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
3636 * @skb: skb to check
3638 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
3639 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
3640 * use this helper, to document places where we make this assertion.
3642 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
3645 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
3649 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
3651 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
3652 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
3653 unsigned int transport_len,
3654 __sum16(*skb_chkf)(struct sk_buff *skb));
3657 * skb_head_is_locked - Determine if the skb->head is locked down
3658 * @skb: skb to check
3660 * The head on skbs build around a head frag can be removed if they are
3661 * not cloned. This function returns true if the skb head is locked down
3662 * due to either being allocated via kmalloc, or by being a clone with
3663 * multiple references to the head.
3665 static inline bool skb_head_is_locked(const struct sk_buff *skb)
3667 return !skb->head_frag || skb_cloned(skb);
3671 * skb_gso_network_seglen - Return length of individual segments of a gso packet
3675 * skb_gso_network_seglen is used to determine the real size of the
3676 * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
3678 * The MAC/L2 header is not accounted for.
3680 static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
3682 unsigned int hdr_len = skb_transport_header(skb) -
3683 skb_network_header(skb);
3684 return hdr_len + skb_gso_transport_seglen(skb);
3687 #endif /* __KERNEL__ */
3688 #endif /* _LINUX_SKBUFF_H */