linux/include/linux/skbuff.h
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   1/*
   2 *      Definitions for the 'struct sk_buff' memory handlers.
   3 *
   4 *      Authors:
   5 *              Alan Cox, <gw4pts@gw4pts.ampr.org>
   6 *              Florian La Roche, <rzsfl@rz.uni-sb.de>
   7 *
   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.
  12 */
  13
  14#ifndef _LINUX_SKBUFF_H
  15#define _LINUX_SKBUFF_H
  16
  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
  24#include <linux/atomic.h>
  25#include <asm/types.h>
  26#include <linux/spinlock.h>
  27#include <linux/net.h>
  28#include <linux/textsearch.h>
  29#include <net/checksum.h>
  30#include <linux/rcupdate.h>
  31#include <linux/dmaengine.h>
  32#include <linux/hrtimer.h>
  33#include <linux/dma-mapping.h>
  34#include <linux/netdev_features.h>
  35
  36/* Don't change this without changing skb_csum_unnecessary! */
  37#define CHECKSUM_NONE 0
  38#define CHECKSUM_UNNECESSARY 1
  39#define CHECKSUM_COMPLETE 2
  40#define CHECKSUM_PARTIAL 3
  41
  42#define SKB_DATA_ALIGN(X)       (((X) + (SMP_CACHE_BYTES - 1)) & \
  43                                 ~(SMP_CACHE_BYTES - 1))
  44#define SKB_WITH_OVERHEAD(X)    \
  45        ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
  46#define SKB_MAX_ORDER(X, ORDER) \
  47        SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
  48#define SKB_MAX_HEAD(X)         (SKB_MAX_ORDER((X), 0))
  49#define SKB_MAX_ALLOC           (SKB_MAX_ORDER(0, 2))
  50
  51/* return minimum truesize of one skb containing X bytes of data */
  52#define SKB_TRUESIZE(X) ((X) +                                          \
  53                         SKB_DATA_ALIGN(sizeof(struct sk_buff)) +       \
  54                         SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
  55
  56/* A. Checksumming of received packets by device.
  57 *
  58 *      NONE: device failed to checksum this packet.
  59 *              skb->csum is undefined.
  60 *
  61 *      UNNECESSARY: device parsed packet and wouldbe verified checksum.
  62 *              skb->csum is undefined.
  63 *            It is bad option, but, unfortunately, many of vendors do this.
  64 *            Apparently with secret goal to sell you new device, when you
  65 *            will add new protocol to your host. F.e. IPv6. 8)
  66 *
  67 *      COMPLETE: the most generic way. Device supplied checksum of _all_
  68 *          the packet as seen by netif_rx in skb->csum.
  69 *          NOTE: Even if device supports only some protocols, but
  70 *          is able to produce some skb->csum, it MUST use COMPLETE,
  71 *          not UNNECESSARY.
  72 *
  73 *      PARTIAL: identical to the case for output below.  This may occur
  74 *          on a packet received directly from another Linux OS, e.g.,
  75 *          a virtualised Linux kernel on the same host.  The packet can
  76 *          be treated in the same way as UNNECESSARY except that on
  77 *          output (i.e., forwarding) the checksum must be filled in
  78 *          by the OS or the hardware.
  79 *
  80 * B. Checksumming on output.
  81 *
  82 *      NONE: skb is checksummed by protocol or csum is not required.
  83 *
  84 *      PARTIAL: device is required to csum packet as seen by hard_start_xmit
  85 *      from skb->csum_start to the end and to record the checksum
  86 *      at skb->csum_start + skb->csum_offset.
  87 *
  88 *      Device must show its capabilities in dev->features, set
  89 *      at device setup time.
  90 *      NETIF_F_HW_CSUM - it is clever device, it is able to checksum
  91 *                        everything.
  92 *      NETIF_F_IP_CSUM - device is dumb. It is able to csum only
  93 *                        TCP/UDP over IPv4. Sigh. Vendors like this
  94 *                        way by an unknown reason. Though, see comment above
  95 *                        about CHECKSUM_UNNECESSARY. 8)
  96 *      NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
  97 *
  98 *      UNNECESSARY: device will do per protocol specific csum. Protocol drivers
  99 *      that do not want net to perform the checksum calculation should use
 100 *      this flag in their outgoing skbs.
 101 *      NETIF_F_FCOE_CRC  this indicates the device can do FCoE FC CRC
 102 *                        offload. Correspondingly, the FCoE protocol driver
 103 *                        stack should use CHECKSUM_UNNECESSARY.
 104 *
 105 *      Any questions? No questions, good.              --ANK
 106 */
 107
 108struct net_device;
 109struct scatterlist;
 110struct pipe_inode_info;
 111
 112#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 113struct nf_conntrack {
 114        atomic_t use;
 115};
 116#endif
 117
 118#ifdef CONFIG_BRIDGE_NETFILTER
 119struct nf_bridge_info {
 120        atomic_t                use;
 121        unsigned int            mask;
 122        struct net_device       *physindev;
 123        struct net_device       *physoutdev;
 124        unsigned long           data[32 / sizeof(unsigned long)];
 125};
 126#endif
 127
 128struct sk_buff_head {
 129        /* These two members must be first. */
 130        struct sk_buff  *next;
 131        struct sk_buff  *prev;
 132
 133        __u32           qlen;
 134        spinlock_t      lock;
 135};
 136
 137struct sk_buff;
 138
 139/* To allow 64K frame to be packed as single skb without frag_list we
 140 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
 141 * buffers which do not start on a page boundary.
 142 *
 143 * Since GRO uses frags we allocate at least 16 regardless of page
 144 * size.
 145 */
 146#if (65536/PAGE_SIZE + 1) < 16
 147#define MAX_SKB_FRAGS 16UL
 148#else
 149#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
 150#endif
 151
 152typedef struct skb_frag_struct skb_frag_t;
 153
 154struct skb_frag_struct {
 155        struct {
 156                struct page *p;
 157        } page;
 158#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
 159        __u32 page_offset;
 160        __u32 size;
 161#else
 162        __u16 page_offset;
 163        __u16 size;
 164#endif
 165};
 166
 167static inline unsigned int skb_frag_size(const skb_frag_t *frag)
 168{
 169        return frag->size;
 170}
 171
 172static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
 173{
 174        frag->size = size;
 175}
 176
 177static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
 178{
 179        frag->size += delta;
 180}
 181
 182static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
 183{
 184        frag->size -= delta;
 185}
 186
 187#define HAVE_HW_TIME_STAMP
 188
 189/**
 190 * struct skb_shared_hwtstamps - hardware time stamps
 191 * @hwtstamp:   hardware time stamp transformed into duration
 192 *              since arbitrary point in time
 193 * @syststamp:  hwtstamp transformed to system time base
 194 *
 195 * Software time stamps generated by ktime_get_real() are stored in
 196 * skb->tstamp. The relation between the different kinds of time
 197 * stamps is as follows:
 198 *
 199 * syststamp and tstamp can be compared against each other in
 200 * arbitrary combinations.  The accuracy of a
 201 * syststamp/tstamp/"syststamp from other device" comparison is
 202 * limited by the accuracy of the transformation into system time
 203 * base. This depends on the device driver and its underlying
 204 * hardware.
 205 *
 206 * hwtstamps can only be compared against other hwtstamps from
 207 * the same device.
 208 *
 209 * This structure is attached to packets as part of the
 210 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
 211 */
 212struct skb_shared_hwtstamps {
 213        ktime_t hwtstamp;
 214        ktime_t syststamp;
 215};
 216
 217/* Definitions for tx_flags in struct skb_shared_info */
 218enum {
 219        /* generate hardware time stamp */
 220        SKBTX_HW_TSTAMP = 1 << 0,
 221
 222        /* generate software time stamp */
 223        SKBTX_SW_TSTAMP = 1 << 1,
 224
 225        /* device driver is going to provide hardware time stamp */
 226        SKBTX_IN_PROGRESS = 1 << 2,
 227
 228        /* device driver supports TX zero-copy buffers */
 229        SKBTX_DEV_ZEROCOPY = 1 << 3,
 230
 231        /* generate wifi status information (where possible) */
 232        SKBTX_WIFI_STATUS = 1 << 4,
 233
 234        /* This indicates at least one fragment might be overwritten
 235         * (as in vmsplice(), sendfile() ...)
 236         * If we need to compute a TX checksum, we'll need to copy
 237         * all frags to avoid possible bad checksum
 238         */
 239        SKBTX_SHARED_FRAG = 1 << 5,
 240};
 241
 242/*
 243 * The callback notifies userspace to release buffers when skb DMA is done in
 244 * lower device, the skb last reference should be 0 when calling this.
 245 * The zerocopy_success argument is true if zero copy transmit occurred,
 246 * false on data copy or out of memory error caused by data copy attempt.
 247 * The ctx field is used to track device context.
 248 * The desc field is used to track userspace buffer index.
 249 */
 250struct ubuf_info {
 251        void (*callback)(struct ubuf_info *, bool zerocopy_success);
 252        void *ctx;
 253        unsigned long desc;
 254};
 255
 256/* This data is invariant across clones and lives at
 257 * the end of the header data, ie. at skb->end.
 258 */
 259struct skb_shared_info {
 260        unsigned char   nr_frags;
 261        __u8            tx_flags;
 262        unsigned short  gso_size;
 263        /* Warning: this field is not always filled in (UFO)! */
 264        unsigned short  gso_segs;
 265        unsigned short  gso_type;
 266        struct sk_buff  *frag_list;
 267        struct skb_shared_hwtstamps hwtstamps;
 268        __be32          ip6_frag_id;
 269
 270        /*
 271         * Warning : all fields before dataref are cleared in __alloc_skb()
 272         */
 273        atomic_t        dataref;
 274
 275        /* Intermediate layers must ensure that destructor_arg
 276         * remains valid until skb destructor */
 277        void *          destructor_arg;
 278
 279        /* must be last field, see pskb_expand_head() */
 280        skb_frag_t      frags[MAX_SKB_FRAGS];
 281};
 282
 283/* We divide dataref into two halves.  The higher 16 bits hold references
 284 * to the payload part of skb->data.  The lower 16 bits hold references to
 285 * the entire skb->data.  A clone of a headerless skb holds the length of
 286 * the header in skb->hdr_len.
 287 *
 288 * All users must obey the rule that the skb->data reference count must be
 289 * greater than or equal to the payload reference count.
 290 *
 291 * Holding a reference to the payload part means that the user does not
 292 * care about modifications to the header part of skb->data.
 293 */
 294#define SKB_DATAREF_SHIFT 16
 295#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
 296
 297
 298enum {
 299        SKB_FCLONE_UNAVAILABLE,
 300        SKB_FCLONE_ORIG,
 301        SKB_FCLONE_CLONE,
 302};
 303
 304enum {
 305        SKB_GSO_TCPV4 = 1 << 0,
 306        SKB_GSO_UDP = 1 << 1,
 307
 308        /* This indicates the skb is from an untrusted source. */
 309        SKB_GSO_DODGY = 1 << 2,
 310
 311        /* This indicates the tcp segment has CWR set. */
 312        SKB_GSO_TCP_ECN = 1 << 3,
 313
 314        SKB_GSO_TCPV6 = 1 << 4,
 315
 316        SKB_GSO_FCOE = 1 << 5,
 317
 318        SKB_GSO_GRE = 1 << 6,
 319};
 320
 321#if BITS_PER_LONG > 32
 322#define NET_SKBUFF_DATA_USES_OFFSET 1
 323#endif
 324
 325#ifdef NET_SKBUFF_DATA_USES_OFFSET
 326typedef unsigned int sk_buff_data_t;
 327#else
 328typedef unsigned char *sk_buff_data_t;
 329#endif
 330
 331#if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
 332    defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
 333#define NET_SKBUFF_NF_DEFRAG_NEEDED 1
 334#endif
 335
 336/** 
 337 *      struct sk_buff - socket buffer
 338 *      @next: Next buffer in list
 339 *      @prev: Previous buffer in list
 340 *      @tstamp: Time we arrived
 341 *      @sk: Socket we are owned by
 342 *      @dev: Device we arrived on/are leaving by
 343 *      @cb: Control buffer. Free for use by every layer. Put private vars here
 344 *      @_skb_refdst: destination entry (with norefcount bit)
 345 *      @sp: the security path, used for xfrm
 346 *      @len: Length of actual data
 347 *      @data_len: Data length
 348 *      @mac_len: Length of link layer header
 349 *      @hdr_len: writable header length of cloned skb
 350 *      @csum: Checksum (must include start/offset pair)
 351 *      @csum_start: Offset from skb->head where checksumming should start
 352 *      @csum_offset: Offset from csum_start where checksum should be stored
 353 *      @priority: Packet queueing priority
 354 *      @local_df: allow local fragmentation
 355 *      @cloned: Head may be cloned (check refcnt to be sure)
 356 *      @ip_summed: Driver fed us an IP checksum
 357 *      @nohdr: Payload reference only, must not modify header
 358 *      @nfctinfo: Relationship of this skb to the connection
 359 *      @pkt_type: Packet class
 360 *      @fclone: skbuff clone status
 361 *      @ipvs_property: skbuff is owned by ipvs
 362 *      @peeked: this packet has been seen already, so stats have been
 363 *              done for it, don't do them again
 364 *      @nf_trace: netfilter packet trace flag
 365 *      @protocol: Packet protocol from driver
 366 *      @destructor: Destruct function
 367 *      @nfct: Associated connection, if any
 368 *      @nfct_reasm: netfilter conntrack re-assembly pointer
 369 *      @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
 370 *      @skb_iif: ifindex of device we arrived on
 371 *      @tc_index: Traffic control index
 372 *      @tc_verd: traffic control verdict
 373 *      @rxhash: the packet hash computed on receive
 374 *      @queue_mapping: Queue mapping for multiqueue devices
 375 *      @ndisc_nodetype: router type (from link layer)
 376 *      @ooo_okay: allow the mapping of a socket to a queue to be changed
 377 *      @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
 378 *              ports.
 379 *      @wifi_acked_valid: wifi_acked was set
 380 *      @wifi_acked: whether frame was acked on wifi or not
 381 *      @no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
 382 *      @dma_cookie: a cookie to one of several possible DMA operations
 383 *              done by skb DMA functions
 384 *      @secmark: security marking
 385 *      @mark: Generic packet mark
 386 *      @dropcount: total number of sk_receive_queue overflows
 387 *      @vlan_tci: vlan tag control information
 388 *      @inner_transport_header: Inner transport layer header (encapsulation)
 389 *      @inner_network_header: Network layer header (encapsulation)
 390 *      @transport_header: Transport layer header
 391 *      @network_header: Network layer header
 392 *      @mac_header: Link layer header
 393 *      @tail: Tail pointer
 394 *      @end: End pointer
 395 *      @head: Head of buffer
 396 *      @data: Data head pointer
 397 *      @truesize: Buffer size
 398 *      @users: User count - see {datagram,tcp}.c
 399 */
 400
 401struct sk_buff {
 402        /* These two members must be first. */
 403        struct sk_buff          *next;
 404        struct sk_buff          *prev;
 405
 406        ktime_t                 tstamp;
 407
 408        struct sock             *sk;
 409        struct net_device       *dev;
 410
 411        /*
 412         * This is the control buffer. It is free to use for every
 413         * layer. Please put your private variables there. If you
 414         * want to keep them across layers you have to do a skb_clone()
 415         * first. This is owned by whoever has the skb queued ATM.
 416         */
 417        char                    cb[48] __aligned(8);
 418
 419        unsigned long           _skb_refdst;
 420#ifdef CONFIG_XFRM
 421        struct  sec_path        *sp;
 422#endif
 423        unsigned int            len,
 424                                data_len;
 425        __u16                   mac_len,
 426                                hdr_len;
 427        union {
 428                __wsum          csum;
 429                struct {
 430                        __u16   csum_start;
 431                        __u16   csum_offset;
 432                };
 433        };
 434        __u32                   priority;
 435        kmemcheck_bitfield_begin(flags1);
 436        __u8                    local_df:1,
 437                                cloned:1,
 438                                ip_summed:2,
 439                                nohdr:1,
 440                                nfctinfo:3;
 441        __u8                    pkt_type:3,
 442                                fclone:2,
 443                                ipvs_property:1,
 444                                peeked:1,
 445                                nf_trace:1;
 446        kmemcheck_bitfield_end(flags1);
 447        __be16                  protocol;
 448
 449        void                    (*destructor)(struct sk_buff *skb);
 450#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 451        struct nf_conntrack     *nfct;
 452#endif
 453#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
 454        struct sk_buff          *nfct_reasm;
 455#endif
 456#ifdef CONFIG_BRIDGE_NETFILTER
 457        struct nf_bridge_info   *nf_bridge;
 458#endif
 459
 460        int                     skb_iif;
 461
 462        __u32                   rxhash;
 463
 464        __u16                   vlan_tci;
 465
 466#ifdef CONFIG_NET_SCHED
 467        __u16                   tc_index;       /* traffic control index */
 468#ifdef CONFIG_NET_CLS_ACT
 469        __u16                   tc_verd;        /* traffic control verdict */
 470#endif
 471#endif
 472
 473        __u16                   queue_mapping;
 474        kmemcheck_bitfield_begin(flags2);
 475#ifdef CONFIG_IPV6_NDISC_NODETYPE
 476        __u8                    ndisc_nodetype:2;
 477#endif
 478        __u8                    pfmemalloc:1;
 479        __u8                    ooo_okay:1;
 480        __u8                    l4_rxhash:1;
 481        __u8                    wifi_acked_valid:1;
 482        __u8                    wifi_acked:1;
 483        __u8                    no_fcs:1;
 484        __u8                    head_frag:1;
 485        /* Encapsulation protocol and NIC drivers should use
 486         * this flag to indicate to each other if the skb contains
 487         * encapsulated packet or not and maybe use the inner packet
 488         * headers if needed
 489         */
 490        __u8                    encapsulation:1;
 491        /* 7/9 bit hole (depending on ndisc_nodetype presence) */
 492        kmemcheck_bitfield_end(flags2);
 493
 494#ifdef CONFIG_NET_DMA
 495        dma_cookie_t            dma_cookie;
 496#endif
 497#ifdef CONFIG_NETWORK_SECMARK
 498        __u32                   secmark;
 499#endif
 500        union {
 501                __u32           mark;
 502                __u32           dropcount;
 503                __u32           reserved_tailroom;
 504        };
 505
 506        sk_buff_data_t          inner_transport_header;
 507        sk_buff_data_t          inner_network_header;
 508        sk_buff_data_t          transport_header;
 509        sk_buff_data_t          network_header;
 510        sk_buff_data_t          mac_header;
 511        /* These elements must be at the end, see alloc_skb() for details.  */
 512        sk_buff_data_t          tail;
 513        sk_buff_data_t          end;
 514        unsigned char           *head,
 515                                *data;
 516        unsigned int            truesize;
 517        atomic_t                users;
 518};
 519
 520#ifdef __KERNEL__
 521/*
 522 *      Handling routines are only of interest to the kernel
 523 */
 524#include <linux/slab.h>
 525
 526
 527#define SKB_ALLOC_FCLONE        0x01
 528#define SKB_ALLOC_RX            0x02
 529
 530/* Returns true if the skb was allocated from PFMEMALLOC reserves */
 531static inline bool skb_pfmemalloc(const struct sk_buff *skb)
 532{
 533        return unlikely(skb->pfmemalloc);
 534}
 535
 536/*
 537 * skb might have a dst pointer attached, refcounted or not.
 538 * _skb_refdst low order bit is set if refcount was _not_ taken
 539 */
 540#define SKB_DST_NOREF   1UL
 541#define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
 542
 543/**
 544 * skb_dst - returns skb dst_entry
 545 * @skb: buffer
 546 *
 547 * Returns skb dst_entry, regardless of reference taken or not.
 548 */
 549static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
 550{
 551        /* If refdst was not refcounted, check we still are in a 
 552         * rcu_read_lock section
 553         */
 554        WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
 555                !rcu_read_lock_held() &&
 556                !rcu_read_lock_bh_held());
 557        return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
 558}
 559
 560/**
 561 * skb_dst_set - sets skb dst
 562 * @skb: buffer
 563 * @dst: dst entry
 564 *
 565 * Sets skb dst, assuming a reference was taken on dst and should
 566 * be released by skb_dst_drop()
 567 */
 568static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
 569{
 570        skb->_skb_refdst = (unsigned long)dst;
 571}
 572
 573extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);
 574
 575/**
 576 * skb_dst_is_noref - Test if skb dst isn't refcounted
 577 * @skb: buffer
 578 */
 579static inline bool skb_dst_is_noref(const struct sk_buff *skb)
 580{
 581        return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
 582}
 583
 584static inline struct rtable *skb_rtable(const struct sk_buff *skb)
 585{
 586        return (struct rtable *)skb_dst(skb);
 587}
 588
 589extern void kfree_skb(struct sk_buff *skb);
 590extern void skb_tx_error(struct sk_buff *skb);
 591extern void consume_skb(struct sk_buff *skb);
 592extern void            __kfree_skb(struct sk_buff *skb);
 593extern struct kmem_cache *skbuff_head_cache;
 594
 595extern void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
 596extern bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 597                             bool *fragstolen, int *delta_truesize);
 598
 599extern struct sk_buff *__alloc_skb(unsigned int size,
 600                                   gfp_t priority, int flags, int node);
 601extern struct sk_buff *build_skb(void *data, unsigned int frag_size);
 602static inline struct sk_buff *alloc_skb(unsigned int size,
 603                                        gfp_t priority)
 604{
 605        return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
 606}
 607
 608static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
 609                                               gfp_t priority)
 610{
 611        return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
 612}
 613
 614extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
 615extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
 616extern struct sk_buff *skb_clone(struct sk_buff *skb,
 617                                 gfp_t priority);
 618extern struct sk_buff *skb_copy(const struct sk_buff *skb,
 619                                gfp_t priority);
 620extern struct sk_buff *__pskb_copy(struct sk_buff *skb,
 621                                 int headroom, gfp_t gfp_mask);
 622
 623extern int             pskb_expand_head(struct sk_buff *skb,
 624                                        int nhead, int ntail,
 625                                        gfp_t gfp_mask);
 626extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
 627                                            unsigned int headroom);
 628extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
 629                                       int newheadroom, int newtailroom,
 630                                       gfp_t priority);
 631extern int             skb_to_sgvec(struct sk_buff *skb,
 632                                    struct scatterlist *sg, int offset,
 633                                    int len);
 634extern int             skb_cow_data(struct sk_buff *skb, int tailbits,
 635                                    struct sk_buff **trailer);
 636extern int             skb_pad(struct sk_buff *skb, int pad);
 637#define dev_kfree_skb(a)        consume_skb(a)
 638
 639extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
 640                        int getfrag(void *from, char *to, int offset,
 641                        int len,int odd, struct sk_buff *skb),
 642                        void *from, int length);
 643
 644struct skb_seq_state {
 645        __u32           lower_offset;
 646        __u32           upper_offset;
 647        __u32           frag_idx;
 648        __u32           stepped_offset;
 649        struct sk_buff  *root_skb;
 650        struct sk_buff  *cur_skb;
 651        __u8            *frag_data;
 652};
 653
 654extern void           skb_prepare_seq_read(struct sk_buff *skb,
 655                                           unsigned int from, unsigned int to,
 656                                           struct skb_seq_state *st);
 657extern unsigned int   skb_seq_read(unsigned int consumed, const u8 **data,
 658                                   struct skb_seq_state *st);
 659extern void           skb_abort_seq_read(struct skb_seq_state *st);
 660
 661extern unsigned int   skb_find_text(struct sk_buff *skb, unsigned int from,
 662                                    unsigned int to, struct ts_config *config,
 663                                    struct ts_state *state);
 664
 665extern void __skb_get_rxhash(struct sk_buff *skb);
 666static inline __u32 skb_get_rxhash(struct sk_buff *skb)
 667{
 668        if (!skb->l4_rxhash)
 669                __skb_get_rxhash(skb);
 670
 671        return skb->rxhash;
 672}
 673
 674#ifdef NET_SKBUFF_DATA_USES_OFFSET
 675static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
 676{
 677        return skb->head + skb->end;
 678}
 679
 680static inline unsigned int skb_end_offset(const struct sk_buff *skb)
 681{
 682        return skb->end;
 683}
 684#else
 685static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
 686{
 687        return skb->end;
 688}
 689
 690static inline unsigned int skb_end_offset(const struct sk_buff *skb)
 691{
 692        return skb->end - skb->head;
 693}
 694#endif
 695
 696/* Internal */
 697#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
 698
 699static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
 700{
 701        return &skb_shinfo(skb)->hwtstamps;
 702}
 703
 704/**
 705 *      skb_queue_empty - check if a queue is empty
 706 *      @list: queue head
 707 *
 708 *      Returns true if the queue is empty, false otherwise.
 709 */
 710static inline int skb_queue_empty(const struct sk_buff_head *list)
 711{
 712        return list->next == (struct sk_buff *)list;
 713}
 714
 715/**
 716 *      skb_queue_is_last - check if skb is the last entry in the queue
 717 *      @list: queue head
 718 *      @skb: buffer
 719 *
 720 *      Returns true if @skb is the last buffer on the list.
 721 */
 722static inline bool skb_queue_is_last(const struct sk_buff_head *list,
 723                                     const struct sk_buff *skb)
 724{
 725        return skb->next == (struct sk_buff *)list;
 726}
 727
 728/**
 729 *      skb_queue_is_first - check if skb is the first entry in the queue
 730 *      @list: queue head
 731 *      @skb: buffer
 732 *
 733 *      Returns true if @skb is the first buffer on the list.
 734 */
 735static inline bool skb_queue_is_first(const struct sk_buff_head *list,
 736                                      const struct sk_buff *skb)
 737{
 738        return skb->prev == (struct sk_buff *)list;
 739}
 740
 741/**
 742 *      skb_queue_next - return the next packet in the queue
 743 *      @list: queue head
 744 *      @skb: current buffer
 745 *
 746 *      Return the next packet in @list after @skb.  It is only valid to
 747 *      call this if skb_queue_is_last() evaluates to false.
 748 */
 749static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
 750                                             const struct sk_buff *skb)
 751{
 752        /* This BUG_ON may seem severe, but if we just return then we
 753         * are going to dereference garbage.
 754         */
 755        BUG_ON(skb_queue_is_last(list, skb));
 756        return skb->next;
 757}
 758
 759/**
 760 *      skb_queue_prev - return the prev packet in the queue
 761 *      @list: queue head
 762 *      @skb: current buffer
 763 *
 764 *      Return the prev packet in @list before @skb.  It is only valid to
 765 *      call this if skb_queue_is_first() evaluates to false.
 766 */
 767static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
 768                                             const struct sk_buff *skb)
 769{
 770        /* This BUG_ON may seem severe, but if we just return then we
 771         * are going to dereference garbage.
 772         */
 773        BUG_ON(skb_queue_is_first(list, skb));
 774        return skb->prev;
 775}
 776
 777/**
 778 *      skb_get - reference buffer
 779 *      @skb: buffer to reference
 780 *
 781 *      Makes another reference to a socket buffer and returns a pointer
 782 *      to the buffer.
 783 */
 784static inline struct sk_buff *skb_get(struct sk_buff *skb)
 785{
 786        atomic_inc(&skb->users);
 787        return skb;
 788}
 789
 790/*
 791 * If users == 1, we are the only owner and are can avoid redundant
 792 * atomic change.
 793 */
 794
 795/**
 796 *      skb_cloned - is the buffer a clone
 797 *      @skb: buffer to check
 798 *
 799 *      Returns true if the buffer was generated with skb_clone() and is
 800 *      one of multiple shared copies of the buffer. Cloned buffers are
 801 *      shared data so must not be written to under normal circumstances.
 802 */
 803static inline int skb_cloned(const struct sk_buff *skb)
 804{
 805        return skb->cloned &&
 806               (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
 807}
 808
 809static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
 810{
 811        might_sleep_if(pri & __GFP_WAIT);
 812
 813        if (skb_cloned(skb))
 814                return pskb_expand_head(skb, 0, 0, pri);
 815
 816        return 0;
 817}
 818
 819/**
 820 *      skb_header_cloned - is the header a clone
 821 *      @skb: buffer to check
 822 *
 823 *      Returns true if modifying the header part of the buffer requires
 824 *      the data to be copied.
 825 */
 826static inline int skb_header_cloned(const struct sk_buff *skb)
 827{
 828        int dataref;
 829
 830        if (!skb->cloned)
 831                return 0;
 832
 833        dataref = atomic_read(&skb_shinfo(skb)->dataref);
 834        dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
 835        return dataref != 1;
 836}
 837
 838/**
 839 *      skb_header_release - release reference to header
 840 *      @skb: buffer to operate on
 841 *
 842 *      Drop a reference to the header part of the buffer.  This is done
 843 *      by acquiring a payload reference.  You must not read from the header
 844 *      part of skb->data after this.
 845 */
 846static inline void skb_header_release(struct sk_buff *skb)
 847{
 848        BUG_ON(skb->nohdr);
 849        skb->nohdr = 1;
 850        atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
 851}
 852
 853/**
 854 *      skb_shared - is the buffer shared
 855 *      @skb: buffer to check
 856 *
 857 *      Returns true if more than one person has a reference to this
 858 *      buffer.
 859 */
 860static inline int skb_shared(const struct sk_buff *skb)
 861{
 862        return atomic_read(&skb->users) != 1;
 863}
 864
 865/**
 866 *      skb_share_check - check if buffer is shared and if so clone it
 867 *      @skb: buffer to check
 868 *      @pri: priority for memory allocation
 869 *
 870 *      If the buffer is shared the buffer is cloned and the old copy
 871 *      drops a reference. A new clone with a single reference is returned.
 872 *      If the buffer is not shared the original buffer is returned. When
 873 *      being called from interrupt status or with spinlocks held pri must
 874 *      be GFP_ATOMIC.
 875 *
 876 *      NULL is returned on a memory allocation failure.
 877 */
 878static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
 879{
 880        might_sleep_if(pri & __GFP_WAIT);
 881        if (skb_shared(skb)) {
 882                struct sk_buff *nskb = skb_clone(skb, pri);
 883
 884                if (likely(nskb))
 885                        consume_skb(skb);
 886                else
 887                        kfree_skb(skb);
 888                skb = nskb;
 889        }
 890        return skb;
 891}
 892
 893/*
 894 *      Copy shared buffers into a new sk_buff. We effectively do COW on
 895 *      packets to handle cases where we have a local reader and forward
 896 *      and a couple of other messy ones. The normal one is tcpdumping
 897 *      a packet thats being forwarded.
 898 */
 899
 900/**
 901 *      skb_unshare - make a copy of a shared buffer
 902 *      @skb: buffer to check
 903 *      @pri: priority for memory allocation
 904 *
 905 *      If the socket buffer is a clone then this function creates a new
 906 *      copy of the data, drops a reference count on the old copy and returns
 907 *      the new copy with the reference count at 1. If the buffer is not a clone
 908 *      the original buffer is returned. When called with a spinlock held or
 909 *      from interrupt state @pri must be %GFP_ATOMIC
 910 *
 911 *      %NULL is returned on a memory allocation failure.
 912 */
 913static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
 914                                          gfp_t pri)
 915{
 916        might_sleep_if(pri & __GFP_WAIT);
 917        if (skb_cloned(skb)) {
 918                struct sk_buff *nskb = skb_copy(skb, pri);
 919                kfree_skb(skb); /* Free our shared copy */
 920                skb = nskb;
 921        }
 922        return skb;
 923}
 924
 925/**
 926 *      skb_peek - peek at the head of an &sk_buff_head
 927 *      @list_: list to peek at
 928 *
 929 *      Peek an &sk_buff. Unlike most other operations you _MUST_
 930 *      be careful with this one. A peek leaves the buffer on the
 931 *      list and someone else may run off with it. You must hold
 932 *      the appropriate locks or have a private queue to do this.
 933 *
 934 *      Returns %NULL for an empty list or a pointer to the head element.
 935 *      The reference count is not incremented and the reference is therefore
 936 *      volatile. Use with caution.
 937 */
 938static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
 939{
 940        struct sk_buff *skb = list_->next;
 941
 942        if (skb == (struct sk_buff *)list_)
 943                skb = NULL;
 944        return skb;
 945}
 946
 947/**
 948 *      skb_peek_next - peek skb following the given one from a queue
 949 *      @skb: skb to start from
 950 *      @list_: list to peek at
 951 *
 952 *      Returns %NULL when the end of the list is met or a pointer to the
 953 *      next element. The reference count is not incremented and the
 954 *      reference is therefore volatile. Use with caution.
 955 */
 956static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
 957                const struct sk_buff_head *list_)
 958{
 959        struct sk_buff *next = skb->next;
 960
 961        if (next == (struct sk_buff *)list_)
 962                next = NULL;
 963        return next;
 964}
 965
 966/**
 967 *      skb_peek_tail - peek at the tail of an &sk_buff_head
 968 *      @list_: list to peek at
 969 *
 970 *      Peek an &sk_buff. Unlike most other operations you _MUST_
 971 *      be careful with this one. A peek leaves the buffer on the
 972 *      list and someone else may run off with it. You must hold
 973 *      the appropriate locks or have a private queue to do this.
 974 *
 975 *      Returns %NULL for an empty list or a pointer to the tail element.
 976 *      The reference count is not incremented and the reference is therefore
 977 *      volatile. Use with caution.
 978 */
 979static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
 980{
 981        struct sk_buff *skb = list_->prev;
 982
 983        if (skb == (struct sk_buff *)list_)
 984                skb = NULL;
 985        return skb;
 986
 987}
 988
 989/**
 990 *      skb_queue_len   - get queue length
 991 *      @list_: list to measure
 992 *
 993 *      Return the length of an &sk_buff queue.
 994 */
 995static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
 996{
 997        return list_->qlen;
 998}
 999
1000/**
1001 *      __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1002 *      @list: queue to initialize
1003 *
1004 *      This initializes only the list and queue length aspects of
1005 *      an sk_buff_head object.  This allows to initialize the list
1006 *      aspects of an sk_buff_head without reinitializing things like
1007 *      the spinlock.  It can also be used for on-stack sk_buff_head
1008 *      objects where the spinlock is known to not be used.
1009 */
1010static inline void __skb_queue_head_init(struct sk_buff_head *list)
1011{
1012        list->prev = list->next = (struct sk_buff *)list;
1013        list->qlen = 0;
1014}
1015
1016/*
1017 * This function creates a split out lock class for each invocation;
1018 * this is needed for now since a whole lot of users of the skb-queue
1019 * infrastructure in drivers have different locking usage (in hardirq)
1020 * than the networking core (in softirq only). In the long run either the
1021 * network layer or drivers should need annotation to consolidate the
1022 * main types of usage into 3 classes.
1023 */
1024static inline void skb_queue_head_init(struct sk_buff_head *list)
1025{
1026        spin_lock_init(&list->lock);
1027        __skb_queue_head_init(list);
1028}
1029
1030static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1031                struct lock_class_key *class)
1032{
1033        skb_queue_head_init(list);
1034        lockdep_set_class(&list->lock, class);
1035}
1036
1037/*
1038 *      Insert an sk_buff on a list.
1039 *
1040 *      The "__skb_xxxx()" functions are the non-atomic ones that
1041 *      can only be called with interrupts disabled.
1042 */
1043extern void        skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
1044static inline void __skb_insert(struct sk_buff *newsk,
1045                                struct sk_buff *prev, struct sk_buff *next,
1046                                struct sk_buff_head *list)
1047{
1048        newsk->next = next;
1049        newsk->prev = prev;
1050        next->prev  = prev->next = newsk;
1051        list->qlen++;
1052}
1053
1054static inline void __skb_queue_splice(const struct sk_buff_head *list,
1055                                      struct sk_buff *prev,
1056                                      struct sk_buff *next)
1057{
1058        struct sk_buff *first = list->next;
1059        struct sk_buff *last = list->prev;
1060
1061        first->prev = prev;
1062        prev->next = first;
1063
1064        last->next = next;
1065        next->prev = last;
1066}
1067
1068/**
1069 *      skb_queue_splice - join two skb lists, this is designed for stacks
1070 *      @list: the new list to add
1071 *      @head: the place to add it in the first list
1072 */
1073static inline void skb_queue_splice(const struct sk_buff_head *list,
1074                                    struct sk_buff_head *head)
1075{
1076        if (!skb_queue_empty(list)) {
1077                __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1078                head->qlen += list->qlen;
1079        }
1080}
1081
1082/**
1083 *      skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1084 *      @list: the new list to add
1085 *      @head: the place to add it in the first list
1086 *
1087 *      The list at @list is reinitialised
1088 */
1089static inline void skb_queue_splice_init(struct sk_buff_head *list,
1090                                         struct sk_buff_head *head)
1091{
1092        if (!skb_queue_empty(list)) {
1093                __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1094                head->qlen += list->qlen;
1095                __skb_queue_head_init(list);
1096        }
1097}
1098
1099/**
1100 *      skb_queue_splice_tail - join two skb lists, each list being a queue
1101 *      @list: the new list to add
1102 *      @head: the place to add it in the first list
1103 */
1104static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1105                                         struct sk_buff_head *head)
1106{
1107        if (!skb_queue_empty(list)) {
1108                __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1109                head->qlen += list->qlen;
1110        }
1111}
1112
1113/**
1114 *      skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1115 *      @list: the new list to add
1116 *      @head: the place to add it in the first list
1117 *
1118 *      Each of the lists is a queue.
1119 *      The list at @list is reinitialised
1120 */
1121static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1122                                              struct sk_buff_head *head)
1123{
1124        if (!skb_queue_empty(list)) {
1125                __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1126                head->qlen += list->qlen;
1127                __skb_queue_head_init(list);
1128        }
1129}
1130
1131/**
1132 *      __skb_queue_after - queue a buffer at the list head
1133 *      @list: list to use
1134 *      @prev: place after this buffer
1135 *      @newsk: buffer to queue
1136 *
1137 *      Queue a buffer int the middle of a list. This function takes no locks
1138 *      and you must therefore hold required locks before calling it.
1139 *
1140 *      A buffer cannot be placed on two lists at the same time.
1141 */
1142static inline void __skb_queue_after(struct sk_buff_head *list,
1143                                     struct sk_buff *prev,
1144                                     struct sk_buff *newsk)
1145{
1146        __skb_insert(newsk, prev, prev->next, list);
1147}
1148
1149extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1150                       struct sk_buff_head *list);
1151
1152static inline void __skb_queue_before(struct sk_buff_head *list,
1153                                      struct sk_buff *next,
1154                                      struct sk_buff *newsk)
1155{
1156        __skb_insert(newsk, next->prev, next, list);
1157}
1158
1159/**
1160 *      __skb_queue_head - queue a buffer at the list head
1161 *      @list: list to use
1162 *      @newsk: buffer to queue
1163 *
1164 *      Queue a buffer at the start of a list. This function takes no locks
1165 *      and you must therefore hold required locks before calling it.
1166 *
1167 *      A buffer cannot be placed on two lists at the same time.
1168 */
1169extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1170static inline void __skb_queue_head(struct sk_buff_head *list,
1171                                    struct sk_buff *newsk)
1172{
1173        __skb_queue_after(list, (struct sk_buff *)list, newsk);
1174}
1175
1176/**
1177 *      __skb_queue_tail - queue a buffer at the list tail
1178 *      @list: list to use
1179 *      @newsk: buffer to queue
1180 *
1181 *      Queue a buffer at the end of a list. This function takes no locks
1182 *      and you must therefore hold required locks before calling it.
1183 *
1184 *      A buffer cannot be placed on two lists at the same time.
1185 */
1186extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1187static inline void __skb_queue_tail(struct sk_buff_head *list,
1188                                   struct sk_buff *newsk)
1189{
1190        __skb_queue_before(list, (struct sk_buff *)list, newsk);
1191}
1192
1193/*
1194 * remove sk_buff from list. _Must_ be called atomically, and with
1195 * the list known..
1196 */
1197extern void        skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1198static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1199{
1200        struct sk_buff *next, *prev;
1201
1202        list->qlen--;
1203        next       = skb->next;
1204        prev       = skb->prev;
1205        skb->next  = skb->prev = NULL;
1206        next->prev = prev;
1207        prev->next = next;
1208}
1209
1210/**
1211 *      __skb_dequeue - remove from the head of the queue
1212 *      @list: list to dequeue from
1213 *
1214 *      Remove the head of the list. This function does not take any locks
1215 *      so must be used with appropriate locks held only. The head item is
1216 *      returned or %NULL if the list is empty.
1217 */
1218extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1219static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1220{
1221        struct sk_buff *skb = skb_peek(list);
1222        if (skb)
1223                __skb_unlink(skb, list);
1224        return skb;
1225}
1226
1227/**
1228 *      __skb_dequeue_tail - remove from the tail of the queue
1229 *      @list: list to dequeue from
1230 *
1231 *      Remove the tail of the list. This function does not take any locks
1232 *      so must be used with appropriate locks held only. The tail item is
1233 *      returned or %NULL if the list is empty.
1234 */
1235extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1236static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1237{
1238        struct sk_buff *skb = skb_peek_tail(list);
1239        if (skb)
1240                __skb_unlink(skb, list);
1241        return skb;
1242}
1243
1244
1245static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1246{
1247        return skb->data_len;
1248}
1249
1250static inline unsigned int skb_headlen(const struct sk_buff *skb)
1251{
1252        return skb->len - skb->data_len;
1253}
1254
1255static inline int skb_pagelen(const struct sk_buff *skb)
1256{
1257        int i, len = 0;
1258
1259        for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1260                len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1261        return len + skb_headlen(skb);
1262}
1263
1264/**
1265 * __skb_fill_page_desc - initialise a paged fragment in an skb
1266 * @skb: buffer containing fragment to be initialised
1267 * @i: paged fragment index to initialise
1268 * @page: the page to use for this fragment
1269 * @off: the offset to the data with @page
1270 * @size: the length of the data
1271 *
1272 * Initialises the @i'th fragment of @skb to point to &size bytes at
1273 * offset @off within @page.
1274 *
1275 * Does not take any additional reference on the fragment.
1276 */
1277static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1278                                        struct page *page, int off, int size)
1279{
1280        skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1281
1282        /*
1283         * Propagate page->pfmemalloc to the skb if we can. The problem is
1284         * that not all callers have unique ownership of the page. If
1285         * pfmemalloc is set, we check the mapping as a mapping implies
1286         * page->index is set (index and pfmemalloc share space).
1287         * If it's a valid mapping, we cannot use page->pfmemalloc but we
1288         * do not lose pfmemalloc information as the pages would not be
1289         * allocated using __GFP_MEMALLOC.
1290         */
1291        frag->page.p              = page;
1292        frag->page_offset         = off;
1293        skb_frag_size_set(frag, size);
1294
1295        page = compound_head(page);
1296        if (page->pfmemalloc && !page->mapping)
1297                skb->pfmemalloc = true;
1298}
1299
1300/**
1301 * skb_fill_page_desc - initialise a paged fragment in an skb
1302 * @skb: buffer containing fragment to be initialised
1303 * @i: paged fragment index to initialise
1304 * @page: the page to use for this fragment
1305 * @off: the offset to the data with @page
1306 * @size: the length of the data
1307 *
1308 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1309 * @skb to point to &size bytes at offset @off within @page. In
1310 * addition updates @skb such that @i is the last fragment.
1311 *
1312 * Does not take any additional reference on the fragment.
1313 */
1314static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1315                                      struct page *page, int off, int size)
1316{
1317        __skb_fill_page_desc(skb, i, page, off, size);
1318        skb_shinfo(skb)->nr_frags = i + 1;
1319}
1320
1321extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1322                            int off, int size, unsigned int truesize);
1323
1324#define SKB_PAGE_ASSERT(skb)    BUG_ON(skb_shinfo(skb)->nr_frags)
1325#define SKB_FRAG_ASSERT(skb)    BUG_ON(skb_has_frag_list(skb))
1326#define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
1327
1328#ifdef NET_SKBUFF_DATA_USES_OFFSET
1329static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1330{
1331        return skb->head + skb->tail;
1332}
1333
1334static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1335{
1336        skb->tail = skb->data - skb->head;
1337}
1338
1339static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1340{
1341        skb_reset_tail_pointer(skb);
1342        skb->tail += offset;
1343}
1344#else /* NET_SKBUFF_DATA_USES_OFFSET */
1345static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1346{
1347        return skb->tail;
1348}
1349
1350static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1351{
1352        skb->tail = skb->data;
1353}
1354
1355static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1356{
1357        skb->tail = skb->data + offset;
1358}
1359
1360#endif /* NET_SKBUFF_DATA_USES_OFFSET */
1361
1362/*
1363 *      Add data to an sk_buff
1364 */
1365extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1366static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1367{
1368        unsigned char *tmp = skb_tail_pointer(skb);
1369        SKB_LINEAR_ASSERT(skb);
1370        skb->tail += len;
1371        skb->len  += len;
1372        return tmp;
1373}
1374
1375extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1376static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1377{
1378        skb->data -= len;
1379        skb->len  += len;
1380        return skb->data;
1381}
1382
1383extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1384static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1385{
1386        skb->len -= len;
1387        BUG_ON(skb->len < skb->data_len);
1388        return skb->data += len;
1389}
1390
1391static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1392{
1393        return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1394}
1395
1396extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1397
1398static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1399{
1400        if (len > skb_headlen(skb) &&
1401            !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1402                return NULL;
1403        skb->len -= len;
1404        return skb->data += len;
1405}
1406
1407static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1408{
1409        return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1410}
1411
1412static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1413{
1414        if (likely(len <= skb_headlen(skb)))
1415                return 1;
1416        if (unlikely(len > skb->len))
1417                return 0;
1418        return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1419}
1420
1421/**
1422 *      skb_headroom - bytes at buffer head
1423 *      @skb: buffer to check
1424 *
1425 *      Return the number of bytes of free space at the head of an &sk_buff.
1426 */
1427static inline unsigned int skb_headroom(const struct sk_buff *skb)
1428{
1429        return skb->data - skb->head;
1430}
1431
1432/**
1433 *      skb_tailroom - bytes at buffer end
1434 *      @skb: buffer to check
1435 *
1436 *      Return the number of bytes of free space at the tail of an sk_buff
1437 */
1438static inline int skb_tailroom(const struct sk_buff *skb)
1439{
1440        return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1441}
1442
1443/**
1444 *      skb_availroom - bytes at buffer end
1445 *      @skb: buffer to check
1446 *
1447 *      Return the number of bytes of free space at the tail of an sk_buff
1448 *      allocated by sk_stream_alloc()
1449 */
1450static inline int skb_availroom(const struct sk_buff *skb)
1451{
1452        if (skb_is_nonlinear(skb))
1453                return 0;
1454
1455        return skb->end - skb->tail - skb->reserved_tailroom;
1456}
1457
1458/**
1459 *      skb_reserve - adjust headroom
1460 *      @skb: buffer to alter
1461 *      @len: bytes to move
1462 *
1463 *      Increase the headroom of an empty &sk_buff by reducing the tail
1464 *      room. This is only allowed for an empty buffer.
1465 */
1466static inline void skb_reserve(struct sk_buff *skb, int len)
1467{
1468        skb->data += len;
1469        skb->tail += len;
1470}
1471
1472static inline void skb_reset_inner_headers(struct sk_buff *skb)
1473{
1474        skb->inner_network_header = skb->network_header;
1475        skb->inner_transport_header = skb->transport_header;
1476}
1477
1478static inline void skb_reset_mac_len(struct sk_buff *skb)
1479{
1480        skb->mac_len = skb->network_header - skb->mac_header;
1481}
1482
1483#ifdef NET_SKBUFF_DATA_USES_OFFSET
1484static inline unsigned char *skb_inner_transport_header(const struct sk_buff
1485                                                        *skb)
1486{
1487        return skb->head + skb->inner_transport_header;
1488}
1489
1490static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
1491{
1492        skb->inner_transport_header = skb->data - skb->head;
1493}
1494
1495static inline void skb_set_inner_transport_header(struct sk_buff *skb,
1496                                                   const int offset)
1497{
1498        skb_reset_inner_transport_header(skb);
1499        skb->inner_transport_header += offset;
1500}
1501
1502static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
1503{
1504        return skb->head + skb->inner_network_header;
1505}
1506
1507static inline void skb_reset_inner_network_header(struct sk_buff *skb)
1508{
1509        skb->inner_network_header = skb->data - skb->head;
1510}
1511
1512static inline void skb_set_inner_network_header(struct sk_buff *skb,
1513                                                const int offset)
1514{
1515        skb_reset_inner_network_header(skb);
1516        skb->inner_network_header += offset;
1517}
1518
1519static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
1520{
1521        return skb->transport_header != ~0U;
1522}
1523
1524static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1525{
1526        return skb->head + skb->transport_header;
1527}
1528
1529static inline void skb_reset_transport_header(struct sk_buff *skb)
1530{
1531        skb->transport_header = skb->data - skb->head;
1532}
1533
1534static inline void skb_set_transport_header(struct sk_buff *skb,
1535                                            const int offset)
1536{
1537        skb_reset_transport_header(skb);
1538        skb->transport_header += offset;
1539}
1540
1541static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1542{
1543        return skb->head + skb->network_header;
1544}
1545
1546static inline void skb_reset_network_header(struct sk_buff *skb)
1547{
1548        skb->network_header = skb->data - skb->head;
1549}
1550
1551static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1552{
1553        skb_reset_network_header(skb);
1554        skb->network_header += offset;
1555}
1556
1557static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1558{
1559        return skb->head + skb->mac_header;
1560}
1561
1562static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1563{
1564        return skb->mac_header != ~0U;
1565}
1566
1567static inline void skb_reset_mac_header(struct sk_buff *skb)
1568{
1569        skb->mac_header = skb->data - skb->head;
1570}
1571
1572static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1573{
1574        skb_reset_mac_header(skb);
1575        skb->mac_header += offset;
1576}
1577
1578#else /* NET_SKBUFF_DATA_USES_OFFSET */
1579static inline unsigned char *skb_inner_transport_header(const struct sk_buff
1580                                                        *skb)
1581{
1582        return skb->inner_transport_header;
1583}
1584
1585static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
1586{
1587        skb->inner_transport_header = skb->data;
1588}
1589
1590static inline void skb_set_inner_transport_header(struct sk_buff *skb,
1591                                                   const int offset)
1592{
1593        skb->inner_transport_header = skb->data + offset;
1594}
1595
1596static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
1597{
1598        return skb->inner_network_header;
1599}
1600
1601static inline void skb_reset_inner_network_header(struct sk_buff *skb)
1602{
1603        skb->inner_network_header = skb->data;
1604}
1605
1606static inline void skb_set_inner_network_header(struct sk_buff *skb,
1607                                                const int offset)
1608{
1609        skb->inner_network_header = skb->data + offset;
1610}
1611
1612static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
1613{
1614        return skb->transport_header != NULL;
1615}
1616
1617static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1618{
1619        return skb->transport_header;
1620}
1621
1622static inline void skb_reset_transport_header(struct sk_buff *skb)
1623{
1624        skb->transport_header = skb->data;
1625}
1626
1627static inline void skb_set_transport_header(struct sk_buff *skb,
1628                                            const int offset)
1629{
1630        skb->transport_header = skb->data + offset;
1631}
1632
1633static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1634{
1635        return skb->network_header;
1636}
1637
1638static inline void skb_reset_network_header(struct sk_buff *skb)
1639{
1640        skb->network_header = skb->data;
1641}
1642
1643static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1644{
1645        skb->network_header = skb->data + offset;
1646}
1647
1648static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1649{
1650        return skb->mac_header;
1651}
1652
1653static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1654{
1655        return skb->mac_header != NULL;
1656}
1657
1658static inline void skb_reset_mac_header(struct sk_buff *skb)
1659{
1660        skb->mac_header = skb->data;
1661}
1662
1663static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1664{
1665        skb->mac_header = skb->data + offset;
1666}
1667#endif /* NET_SKBUFF_DATA_USES_OFFSET */
1668
1669static inline void skb_mac_header_rebuild(struct sk_buff *skb)
1670{
1671        if (skb_mac_header_was_set(skb)) {
1672                const unsigned char *old_mac = skb_mac_header(skb);
1673
1674                skb_set_mac_header(skb, -skb->mac_len);
1675                memmove(skb_mac_header(skb), old_mac, skb->mac_len);
1676        }
1677}
1678
1679static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1680{
1681        return skb->csum_start - skb_headroom(skb);
1682}
1683
1684static inline int skb_transport_offset(const struct sk_buff *skb)
1685{
1686        return skb_transport_header(skb) - skb->data;
1687}
1688
1689static inline u32 skb_network_header_len(const struct sk_buff *skb)
1690{
1691        return skb->transport_header - skb->network_header;
1692}
1693
1694static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
1695{
1696        return skb->inner_transport_header - skb->inner_network_header;
1697}
1698
1699static inline int skb_network_offset(const struct sk_buff *skb)
1700{
1701        return skb_network_header(skb) - skb->data;
1702}
1703
1704static inline int skb_inner_network_offset(const struct sk_buff *skb)
1705{
1706        return skb_inner_network_header(skb) - skb->data;
1707}
1708
1709static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1710{
1711        return pskb_may_pull(skb, skb_network_offset(skb) + len);
1712}
1713
1714/*
1715 * CPUs often take a performance hit when accessing unaligned memory
1716 * locations. The actual performance hit varies, it can be small if the
1717 * hardware handles it or large if we have to take an exception and fix it
1718 * in software.
1719 *
1720 * Since an ethernet header is 14 bytes network drivers often end up with
1721 * the IP header at an unaligned offset. The IP header can be aligned by
1722 * shifting the start of the packet by 2 bytes. Drivers should do this
1723 * with:
1724 *
1725 * skb_reserve(skb, NET_IP_ALIGN);
1726 *
1727 * The downside to this alignment of the IP header is that the DMA is now
1728 * unaligned. On some architectures the cost of an unaligned DMA is high
1729 * and this cost outweighs the gains made by aligning the IP header.
1730 *
1731 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1732 * to be overridden.
1733 */
1734#ifndef NET_IP_ALIGN
1735#define NET_IP_ALIGN    2
1736#endif
1737
1738/*
1739 * The networking layer reserves some headroom in skb data (via
1740 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1741 * the header has to grow. In the default case, if the header has to grow
1742 * 32 bytes or less we avoid the reallocation.
1743 *
1744 * Unfortunately this headroom changes the DMA alignment of the resulting
1745 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1746 * on some architectures. An architecture can override this value,
1747 * perhaps setting it to a cacheline in size (since that will maintain
1748 * cacheline alignment of the DMA). It must be a power of 2.
1749 *
1750 * Various parts of the networking layer expect at least 32 bytes of
1751 * headroom, you should not reduce this.
1752 *
1753 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1754 * to reduce average number of cache lines per packet.
1755 * get_rps_cpus() for example only access one 64 bytes aligned block :
1756 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1757 */
1758#ifndef NET_SKB_PAD
1759#define NET_SKB_PAD     max(32, L1_CACHE_BYTES)
1760#endif
1761
1762extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1763
1764static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1765{
1766        if (unlikely(skb_is_nonlinear(skb))) {
1767                WARN_ON(1);
1768                return;
1769        }
1770        skb->len = len;
1771        skb_set_tail_pointer(skb, len);
1772}
1773
1774extern void skb_trim(struct sk_buff *skb, unsigned int len);
1775
1776static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1777{
1778        if (skb->data_len)
1779                return ___pskb_trim(skb, len);
1780        __skb_trim(skb, len);
1781        return 0;
1782}
1783
1784static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1785{
1786        return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1787}
1788
1789/**
1790 *      pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1791 *      @skb: buffer to alter
1792 *      @len: new length
1793 *
1794 *      This is identical to pskb_trim except that the caller knows that
1795 *      the skb is not cloned so we should never get an error due to out-
1796 *      of-memory.
1797 */
1798static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1799{
1800        int err = pskb_trim(skb, len);
1801        BUG_ON(err);
1802}
1803
1804/**
1805 *      skb_orphan - orphan a buffer
1806 *      @skb: buffer to orphan
1807 *
1808 *      If a buffer currently has an owner then we call the owner's
1809 *      destructor function and make the @skb unowned. The buffer continues
1810 *      to exist but is no longer charged to its former owner.
1811 */
1812static inline void skb_orphan(struct sk_buff *skb)
1813{
1814        if (skb->destructor)
1815                skb->destructor(skb);
1816        skb->destructor = NULL;
1817        skb->sk         = NULL;
1818}
1819
1820/**
1821 *      skb_orphan_frags - orphan the frags contained in a buffer
1822 *      @skb: buffer to orphan frags from
1823 *      @gfp_mask: allocation mask for replacement pages
1824 *
1825 *      For each frag in the SKB which needs a destructor (i.e. has an
1826 *      owner) create a copy of that frag and release the original
1827 *      page by calling the destructor.
1828 */
1829static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
1830{
1831        if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
1832                return 0;
1833        return skb_copy_ubufs(skb, gfp_mask);
1834}
1835
1836/**
1837 *      __skb_queue_purge - empty a list
1838 *      @list: list to empty
1839 *
1840 *      Delete all buffers on an &sk_buff list. Each buffer is removed from
1841 *      the list and one reference dropped. This function does not take the
1842 *      list lock and the caller must hold the relevant locks to use it.
1843 */
1844extern void skb_queue_purge(struct sk_buff_head *list);
1845static inline void __skb_queue_purge(struct sk_buff_head *list)
1846{
1847        struct sk_buff *skb;
1848        while ((skb = __skb_dequeue(list)) != NULL)
1849                kfree_skb(skb);
1850}
1851
1852#define NETDEV_FRAG_PAGE_MAX_ORDER get_order(32768)
1853#define NETDEV_FRAG_PAGE_MAX_SIZE  (PAGE_SIZE << NETDEV_FRAG_PAGE_MAX_ORDER)
1854#define NETDEV_PAGECNT_MAX_BIAS    NETDEV_FRAG_PAGE_MAX_SIZE
1855
1856extern void *netdev_alloc_frag(unsigned int fragsz);
1857
1858extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1859                                          unsigned int length,
1860                                          gfp_t gfp_mask);
1861
1862/**
1863 *      netdev_alloc_skb - allocate an skbuff for rx on a specific device
1864 *      @dev: network device to receive on
1865 *      @length: length to allocate
1866 *
1867 *      Allocate a new &sk_buff and assign it a usage count of one. The
1868 *      buffer has unspecified headroom built in. Users should allocate
1869 *      the headroom they think they need without accounting for the
1870 *      built in space. The built in space is used for optimisations.
1871 *
1872 *      %NULL is returned if there is no free memory. Although this function
1873 *      allocates memory it can be called from an interrupt.
1874 */
1875static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1876                                               unsigned int length)
1877{
1878        return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1879}
1880
1881/* legacy helper around __netdev_alloc_skb() */
1882static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1883                                              gfp_t gfp_mask)
1884{
1885        return __netdev_alloc_skb(NULL, length, gfp_mask);
1886}
1887
1888/* legacy helper around netdev_alloc_skb() */
1889static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1890{
1891        return netdev_alloc_skb(NULL, length);
1892}
1893
1894
1895static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1896                unsigned int length, gfp_t gfp)
1897{
1898        struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1899
1900        if (NET_IP_ALIGN && skb)
1901                skb_reserve(skb, NET_IP_ALIGN);
1902        return skb;
1903}
1904
1905static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1906                unsigned int length)
1907{
1908        return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1909}
1910
1911/*
1912 *      __skb_alloc_page - allocate pages for ps-rx on a skb and preserve pfmemalloc data
1913 *      @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1914 *      @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1915 *      @order: size of the allocation
1916 *
1917 *      Allocate a new page.
1918 *
1919 *      %NULL is returned if there is no free memory.
1920*/
1921static inline struct page *__skb_alloc_pages(gfp_t gfp_mask,
1922                                              struct sk_buff *skb,
1923                                              unsigned int order)
1924{
1925        struct page *page;
1926
1927        gfp_mask |= __GFP_COLD;
1928
1929        if (!(gfp_mask & __GFP_NOMEMALLOC))
1930                gfp_mask |= __GFP_MEMALLOC;
1931
1932        page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
1933        if (skb && page && page->pfmemalloc)
1934                skb->pfmemalloc = true;
1935
1936        return page;
1937}
1938
1939/**
1940 *      __skb_alloc_page - allocate a page for ps-rx for a given skb and preserve pfmemalloc data
1941 *      @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1942 *      @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1943 *
1944 *      Allocate a new page.
1945 *
1946 *      %NULL is returned if there is no free memory.
1947 */
1948static inline struct page *__skb_alloc_page(gfp_t gfp_mask,
1949                                             struct sk_buff *skb)
1950{
1951        return __skb_alloc_pages(gfp_mask, skb, 0);
1952}
1953
1954/**
1955 *      skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
1956 *      @page: The page that was allocated from skb_alloc_page
1957 *      @skb: The skb that may need pfmemalloc set
1958 */
1959static inline void skb_propagate_pfmemalloc(struct page *page,
1960                                             struct sk_buff *skb)
1961{
1962        if (page && page->pfmemalloc)
1963                skb->pfmemalloc = true;
1964}
1965
1966/**
1967 * skb_frag_page - retrieve the page refered to by a paged fragment
1968 * @frag: the paged fragment
1969 *
1970 * Returns the &struct page associated with @frag.
1971 */
1972static inline struct page *skb_frag_page(const skb_frag_t *frag)
1973{
1974        return frag->page.p;
1975}
1976
1977/**
1978 * __skb_frag_ref - take an addition reference on a paged fragment.
1979 * @frag: the paged fragment
1980 *
1981 * Takes an additional reference on the paged fragment @frag.
1982 */
1983static inline void __skb_frag_ref(skb_frag_t *frag)
1984{
1985        get_page(skb_frag_page(frag));
1986}
1987
1988/**
1989 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
1990 * @skb: the buffer
1991 * @f: the fragment offset.
1992 *
1993 * Takes an additional reference on the @f'th paged fragment of @skb.
1994 */
1995static inline void skb_frag_ref(struct sk_buff *skb, int f)
1996{
1997        __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
1998}
1999
2000/**
2001 * __skb_frag_unref - release a reference on a paged fragment.
2002 * @frag: the paged fragment
2003 *
2004 * Releases a reference on the paged fragment @frag.
2005 */
2006static inline void __skb_frag_unref(skb_frag_t *frag)
2007{
2008        put_page(skb_frag_page(frag));
2009}
2010
2011/**
2012 * skb_frag_unref - release a reference on a paged fragment of an skb.
2013 * @skb: the buffer
2014 * @f: the fragment offset
2015 *
2016 * Releases a reference on the @f'th paged fragment of @skb.
2017 */
2018static inline void skb_frag_unref(struct sk_buff *skb, int f)
2019{
2020        __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2021}
2022
2023/**
2024 * skb_frag_address - gets the address of the data contained in a paged fragment
2025 * @frag: the paged fragment buffer
2026 *
2027 * Returns the address of the data within @frag. The page must already
2028 * be mapped.
2029 */
2030static inline void *skb_frag_address(const skb_frag_t *frag)
2031{
2032        return page_address(skb_frag_page(frag)) + frag->page_offset;
2033}
2034
2035/**
2036 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2037 * @frag: the paged fragment buffer
2038 *
2039 * Returns the address of the data within @frag. Checks that the page
2040 * is mapped and returns %NULL otherwise.
2041 */
2042static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2043{
2044        void *ptr = page_address(skb_frag_page(frag));
2045        if (unlikely(!ptr))
2046                return NULL;
2047
2048        return ptr + frag->page_offset;
2049}
2050
2051/**
2052 * __skb_frag_set_page - sets the page contained in a paged fragment
2053 * @frag: the paged fragment
2054 * @page: the page to set
2055 *
2056 * Sets the fragment @frag to contain @page.
2057 */
2058static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2059{
2060        frag->page.p = page;
2061}
2062
2063/**
2064 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2065 * @skb: the buffer
2066 * @f: the fragment offset
2067 * @page: the page to set
2068 *
2069 * Sets the @f'th fragment of @skb to contain @page.
2070 */
2071static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2072                                     struct page *page)
2073{
2074        __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2075}
2076
2077/**
2078 * skb_frag_dma_map - maps a paged fragment via the DMA API
2079 * @dev: the device to map the fragment to
2080 * @frag: the paged fragment to map
2081 * @offset: the offset within the fragment (starting at the
2082 *          fragment's own offset)
2083 * @size: the number of bytes to map
2084 * @dir: the direction of the mapping (%PCI_DMA_*)
2085 *
2086 * Maps the page associated with @frag to @device.
2087 */
2088static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2089                                          const skb_frag_t *frag,
2090                                          size_t offset, size_t size,
2091                                          enum dma_data_direction dir)
2092{
2093        return dma_map_page(dev, skb_frag_page(frag),
2094                            frag->page_offset + offset, size, dir);
2095}
2096
2097static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2098                                        gfp_t gfp_mask)
2099{
2100        return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2101}
2102
2103/**
2104 *      skb_clone_writable - is the header of a clone writable
2105 *      @skb: buffer to check
2106 *      @len: length up to which to write
2107 *
2108 *      Returns true if modifying the header part of the cloned buffer
2109 *      does not requires the data to be copied.
2110 */
2111static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2112{
2113        return !skb_header_cloned(skb) &&
2114               skb_headroom(skb) + len <= skb->hdr_len;
2115}
2116
2117static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2118                            int cloned)
2119{
2120        int delta = 0;
2121
2122        if (headroom > skb_headroom(skb))
2123                delta = headroom - skb_headroom(skb);
2124
2125        if (delta || cloned)
2126                return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2127                                        GFP_ATOMIC);
2128        return 0;
2129}
2130
2131/**
2132 *      skb_cow - copy header of skb when it is required
2133 *      @skb: buffer to cow
2134 *      @headroom: needed headroom
2135 *
2136 *      If the skb passed lacks sufficient headroom or its data part
2137 *      is shared, data is reallocated. If reallocation fails, an error
2138 *      is returned and original skb is not changed.
2139 *
2140 *      The result is skb with writable area skb->head...skb->tail
2141 *      and at least @headroom of space at head.
2142 */
2143static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2144{
2145        return __skb_cow(skb, headroom, skb_cloned(skb));
2146}
2147
2148/**
2149 *      skb_cow_head - skb_cow but only making the head writable
2150 *      @skb: buffer to cow
2151 *      @headroom: needed headroom
2152 *
2153 *      This function is identical to skb_cow except that we replace the
2154 *      skb_cloned check by skb_header_cloned.  It should be used when
2155 *      you only need to push on some header and do not need to modify
2156 *      the data.
2157 */
2158static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2159{
2160        return __skb_cow(skb, headroom, skb_header_cloned(skb));
2161}
2162
2163/**
2164 *      skb_padto       - pad an skbuff up to a minimal size
2165 *      @skb: buffer to pad
2166 *      @len: minimal length
2167 *
2168 *      Pads up a buffer to ensure the trailing bytes exist and are
2169 *      blanked. If the buffer already contains sufficient data it
2170 *      is untouched. Otherwise it is extended. Returns zero on
2171 *      success. The skb is freed on error.
2172 */
2173 
2174static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2175{
2176        unsigned int size = skb->len;
2177        if (likely(size >= len))
2178                return 0;
2179        return skb_pad(skb, len - size);
2180}
2181
2182static inline int skb_add_data(struct sk_buff *skb,
2183                               char __user *from, int copy)
2184{
2185        const int off = skb->len;
2186
2187        if (skb->ip_summed == CHECKSUM_NONE) {
2188                int err = 0;
2189                __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
2190                                                            copy, 0, &err);
2191                if (!err) {
2192                        skb->csum = csum_block_add(skb->csum, csum, off);
2193                        return 0;
2194                }
2195        } else if (!copy_from_user(skb_put(skb, copy), from, copy))
2196                return 0;
2197
2198        __skb_trim(skb, off);
2199        return -EFAULT;
2200}
2201
2202static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2203                                    const struct page *page, int off)
2204{
2205        if (i) {
2206                const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2207
2208                return page == skb_frag_page(frag) &&
2209                       off == frag->page_offset + skb_frag_size(frag);
2210        }
2211        return false;
2212}
2213
2214static inline int __skb_linearize(struct sk_buff *skb)
2215{
2216        return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2217}
2218
2219/**
2220 *      skb_linearize - convert paged skb to linear one
2221 *      @skb: buffer to linarize
2222 *
2223 *      If there is no free memory -ENOMEM is returned, otherwise zero
2224 *      is returned and the old skb data released.
2225 */
2226static inline int skb_linearize(struct sk_buff *skb)
2227{
2228        return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2229}
2230
2231/**
2232 * skb_has_shared_frag - can any frag be overwritten
2233 * @skb: buffer to test
2234 *
2235 * Return true if the skb has at least one frag that might be modified
2236 * by an external entity (as in vmsplice()/sendfile())
2237 */
2238static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2239{
2240        return skb_is_nonlinear(skb) &&
2241               skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2242}
2243
2244/**
2245 *      skb_linearize_cow - make sure skb is linear and writable
2246 *      @skb: buffer to process
2247 *
2248 *      If there is no free memory -ENOMEM is returned, otherwise zero
2249 *      is returned and the old skb data released.
2250 */
2251static inline int skb_linearize_cow(struct sk_buff *skb)
2252{
2253        return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2254               __skb_linearize(skb) : 0;
2255}
2256
2257/**
2258 *      skb_postpull_rcsum - update checksum for received skb after pull
2259 *      @skb: buffer to update
2260 *      @start: start of data before pull
2261 *      @len: length of data pulled
2262 *
2263 *      After doing a pull on a received packet, you need to call this to
2264 *      update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2265 *      CHECKSUM_NONE so that it can be recomputed from scratch.
2266 */
2267
2268static inline void skb_postpull_rcsum(struct sk_buff *skb,
2269                                      const void *start, unsigned int len)
2270{
2271        if (skb->ip_summed == CHECKSUM_COMPLETE)
2272                skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
2273}
2274
2275unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2276
2277/**
2278 *      pskb_trim_rcsum - trim received skb and update checksum
2279 *      @skb: buffer to trim
2280 *      @len: new length
2281 *
2282 *      This is exactly the same as pskb_trim except that it ensures the
2283 *      checksum of received packets are still valid after the operation.
2284 */
2285
2286static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2287{
2288        if (likely(len >= skb->len))
2289                return 0;
2290        if (skb->ip_summed == CHECKSUM_COMPLETE)
2291                skb->ip_summed = CHECKSUM_NONE;
2292        return __pskb_trim(skb, len);
2293}
2294
2295#define skb_queue_walk(queue, skb) \
2296                for (skb = (queue)->next;                                       \
2297                     skb != (struct sk_buff *)(queue);                          \
2298                     skb = skb->next)
2299
2300#define skb_queue_walk_safe(queue, skb, tmp)                                    \
2301                for (skb = (queue)->next, tmp = skb->next;                      \
2302                     skb != (struct sk_buff *)(queue);                          \
2303                     skb = tmp, tmp = skb->next)
2304
2305#define skb_queue_walk_from(queue, skb)                                         \
2306                for (; skb != (struct sk_buff *)(queue);                        \
2307                     skb = skb->next)
2308
2309#define skb_queue_walk_from_safe(queue, skb, tmp)                               \
2310                for (tmp = skb->next;                                           \
2311                     skb != (struct sk_buff *)(queue);                          \
2312                     skb = tmp, tmp = skb->next)
2313
2314#define skb_queue_reverse_walk(queue, skb) \
2315                for (skb = (queue)->prev;                                       \
2316                     skb != (struct sk_buff *)(queue);                          \
2317                     skb = skb->prev)
2318
2319#define skb_queue_reverse_walk_safe(queue, skb, tmp)                            \
2320                for (skb = (queue)->prev, tmp = skb->prev;                      \
2321                     skb != (struct sk_buff *)(queue);                          \
2322                     skb = tmp, tmp = skb->prev)
2323
2324#define skb_queue_reverse_walk_from_safe(queue, skb, tmp)                       \
2325                for (tmp = skb->prev;                                           \
2326                     skb != (struct sk_buff *)(queue);                          \
2327                     skb = tmp, tmp = skb->prev)
2328
2329static inline bool skb_has_frag_list(const struct sk_buff *skb)
2330{
2331        return skb_shinfo(skb)->frag_list != NULL;
2332}
2333
2334static inline void skb_frag_list_init(struct sk_buff *skb)
2335{
2336        skb_shinfo(skb)->frag_list = NULL;
2337}
2338
2339static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2340{
2341        frag->next = skb_shinfo(skb)->frag_list;
2342        skb_shinfo(skb)->frag_list = frag;
2343}
2344
2345#define skb_walk_frags(skb, iter)       \
2346        for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2347
2348extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2349                                           int *peeked, int *off, int *err);
2350extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
2351                                         int noblock, int *err);
2352extern unsigned int    datagram_poll(struct file *file, struct socket *sock,
2353                                     struct poll_table_struct *wait);
2354extern int             skb_copy_datagram_iovec(const struct sk_buff *from,
2355                                               int offset, struct iovec *to,
2356                                               int size);
2357extern int             skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
2358                                                        int hlen,
2359                                                        struct iovec *iov);
2360extern int             skb_copy_datagram_from_iovec(struct sk_buff *skb,
2361                                                    int offset,
2362                                                    const struct iovec *from,
2363                                                    int from_offset,
2364                                                    int len);
2365extern int             skb_copy_datagram_const_iovec(const struct sk_buff *from,
2366                                                     int offset,
2367                                                     const struct iovec *to,
2368                                                     int to_offset,
2369                                                     int size);
2370extern void            skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2371extern void            skb_free_datagram_locked(struct sock *sk,
2372                                                struct sk_buff *skb);
2373extern int             skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
2374                                         unsigned int flags);
2375extern __wsum          skb_checksum(const struct sk_buff *skb, int offset,
2376                                    int len, __wsum csum);
2377extern int             skb_copy_bits(const struct sk_buff *skb, int offset,
2378                                     void *to, int len);
2379extern int             skb_store_bits(struct sk_buff *skb, int offset,
2380                                      const void *from, int len);
2381extern __wsum          skb_copy_and_csum_bits(const struct sk_buff *skb,
2382                                              int offset, u8 *to, int len,
2383                                              __wsum csum);
2384extern int             skb_splice_bits(struct sk_buff *skb,
2385                                                unsigned int offset,
2386                                                struct pipe_inode_info *pipe,
2387                                                unsigned int len,
2388                                                unsigned int flags);
2389extern void            skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2390extern void            skb_split(struct sk_buff *skb,
2391                                 struct sk_buff *skb1, const u32 len);
2392extern int             skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
2393                                 int shiftlen);
2394
2395extern struct sk_buff *skb_segment(struct sk_buff *skb,
2396                                   netdev_features_t features);
2397
2398static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2399                                       int len, void *buffer)
2400{
2401        int hlen = skb_headlen(skb);
2402
2403        if (hlen - offset >= len)
2404                return skb->data + offset;
2405
2406        if (skb_copy_bits(skb, offset, buffer, len) < 0)
2407                return NULL;
2408
2409        return buffer;
2410}
2411
2412static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2413                                             void *to,
2414                                             const unsigned int len)
2415{
2416        memcpy(to, skb->data, len);
2417}
2418
2419static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2420                                                    const int offset, void *to,
2421                                                    const unsigned int len)
2422{
2423        memcpy(to, skb->data + offset, len);
2424}
2425
2426static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2427                                           const void *from,
2428                                           const unsigned int len)
2429{
2430        memcpy(skb->data, from, len);
2431}
2432
2433static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2434                                                  const int offset,
2435                                                  const void *from,
2436                                                  const unsigned int len)
2437{
2438        memcpy(skb->data + offset, from, len);
2439}
2440
2441extern void skb_init(void);
2442
2443static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2444{
2445        return skb->tstamp;
2446}
2447
2448/**
2449 *      skb_get_timestamp - get timestamp from a skb
2450 *      @skb: skb to get stamp from
2451 *      @stamp: pointer to struct timeval to store stamp in
2452 *
2453 *      Timestamps are stored in the skb as offsets to a base timestamp.
2454 *      This function converts the offset back to a struct timeval and stores
2455 *      it in stamp.
2456 */
2457static inline void skb_get_timestamp(const struct sk_buff *skb,
2458                                     struct timeval *stamp)
2459{
2460        *stamp = ktime_to_timeval(skb->tstamp);
2461}
2462
2463static inline void skb_get_timestampns(const struct sk_buff *skb,
2464                                       struct timespec *stamp)
2465{
2466        *stamp = ktime_to_timespec(skb->tstamp);
2467}
2468
2469static inline void __net_timestamp(struct sk_buff *skb)
2470{
2471        skb->tstamp = ktime_get_real();
2472}
2473
2474static inline ktime_t net_timedelta(ktime_t t)
2475{
2476        return ktime_sub(ktime_get_real(), t);
2477}
2478
2479static inline ktime_t net_invalid_timestamp(void)
2480{
2481        return ktime_set(0, 0);
2482}
2483
2484extern void skb_timestamping_init(void);
2485
2486#ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2487
2488extern void skb_clone_tx_timestamp(struct sk_buff *skb);
2489extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
2490
2491#else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2492
2493static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2494{
2495}
2496
2497static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2498{
2499        return false;
2500}
2501
2502#endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2503
2504/**
2505 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2506 *
2507 * PHY drivers may accept clones of transmitted packets for
2508 * timestamping via their phy_driver.txtstamp method. These drivers
2509 * must call this function to return the skb back to the stack, with
2510 * or without a timestamp.
2511 *
2512 * @skb: clone of the the original outgoing packet
2513 * @hwtstamps: hardware time stamps, may be NULL if not available
2514 *
2515 */
2516void skb_complete_tx_timestamp(struct sk_buff *skb,
2517                               struct skb_shared_hwtstamps *hwtstamps);
2518
2519/**
2520 * skb_tstamp_tx - queue clone of skb with send time stamps
2521 * @orig_skb:   the original outgoing packet
2522 * @hwtstamps:  hardware time stamps, may be NULL if not available
2523 *
2524 * If the skb has a socket associated, then this function clones the
2525 * skb (thus sharing the actual data and optional structures), stores
2526 * the optional hardware time stamping information (if non NULL) or
2527 * generates a software time stamp (otherwise), then queues the clone
2528 * to the error queue of the socket.  Errors are silently ignored.
2529 */
2530extern void skb_tstamp_tx(struct sk_buff *orig_skb,
2531                        struct skb_shared_hwtstamps *hwtstamps);
2532
2533static inline void sw_tx_timestamp(struct sk_buff *skb)
2534{
2535        if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2536            !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2537                skb_tstamp_tx(skb, NULL);
2538}
2539
2540/**
2541 * skb_tx_timestamp() - Driver hook for transmit timestamping
2542 *
2543 * Ethernet MAC Drivers should call this function in their hard_xmit()
2544 * function immediately before giving the sk_buff to the MAC hardware.
2545 *
2546 * @skb: A socket buffer.
2547 */
2548static inline void skb_tx_timestamp(struct sk_buff *skb)
2549{
2550        skb_clone_tx_timestamp(skb);
2551        sw_tx_timestamp(skb);
2552}
2553
2554/**
2555 * skb_complete_wifi_ack - deliver skb with wifi status
2556 *
2557 * @skb: the original outgoing packet
2558 * @acked: ack status
2559 *
2560 */
2561void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
2562
2563extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2564extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
2565
2566static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2567{
2568        return skb->ip_summed & CHECKSUM_UNNECESSARY;
2569}
2570
2571/**
2572 *      skb_checksum_complete - Calculate checksum of an entire packet
2573 *      @skb: packet to process
2574 *
2575 *      This function calculates the checksum over the entire packet plus
2576 *      the value of skb->csum.  The latter can be used to supply the
2577 *      checksum of a pseudo header as used by TCP/UDP.  It returns the
2578 *      checksum.
2579 *
2580 *      For protocols that contain complete checksums such as ICMP/TCP/UDP,
2581 *      this function can be used to verify that checksum on received
2582 *      packets.  In that case the function should return zero if the
2583 *      checksum is correct.  In particular, this function will return zero
2584 *      if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2585 *      hardware has already verified the correctness of the checksum.
2586 */
2587static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2588{
2589        return skb_csum_unnecessary(skb) ?
2590               0 : __skb_checksum_complete(skb);
2591}
2592
2593#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2594extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
2595static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2596{
2597        if (nfct && atomic_dec_and_test(&nfct->use))
2598                nf_conntrack_destroy(nfct);
2599}
2600static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2601{
2602        if (nfct)
2603                atomic_inc(&nfct->use);
2604}
2605#endif
2606#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2607static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
2608{
2609        if (skb)
2610                atomic_inc(&skb->users);
2611}
2612static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
2613{
2614        if (skb)
2615                kfree_skb(skb);
2616}
2617#endif
2618#ifdef CONFIG_BRIDGE_NETFILTER
2619static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2620{
2621        if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2622                kfree(nf_bridge);
2623}
2624static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2625{
2626        if (nf_bridge)
2627                atomic_inc(&nf_bridge->use);
2628}
2629#endif /* CONFIG_BRIDGE_NETFILTER */
2630static inline void nf_reset(struct sk_buff *skb)
2631{
2632#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2633        nf_conntrack_put(skb->nfct);
2634        skb->nfct = NULL;
2635#endif
2636#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2637        nf_conntrack_put_reasm(skb->nfct_reasm);
2638        skb->nfct_reasm = NULL;
2639#endif
2640#ifdef CONFIG_BRIDGE_NETFILTER
2641        nf_bridge_put(skb->nf_bridge);
2642        skb->nf_bridge = NULL;
2643#endif
2644}
2645
2646static inline void nf_reset_trace(struct sk_buff *skb)
2647{
2648#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
2649        skb->nf_trace = 0;
2650#endif
2651}
2652
2653/* Note: This doesn't put any conntrack and bridge info in dst. */
2654static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2655{
2656#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2657        dst->nfct = src->nfct;
2658        nf_conntrack_get(src->nfct);
2659        dst->nfctinfo = src->nfctinfo;
2660#endif
2661#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2662        dst->nfct_reasm = src->nfct_reasm;
2663        nf_conntrack_get_reasm(src->nfct_reasm);
2664#endif
2665#ifdef CONFIG_BRIDGE_NETFILTER
2666        dst->nf_bridge  = src->nf_bridge;
2667        nf_bridge_get(src->nf_bridge);
2668#endif
2669}
2670
2671static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2672{
2673#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2674        nf_conntrack_put(dst->nfct);
2675#endif
2676#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2677        nf_conntrack_put_reasm(dst->nfct_reasm);
2678#endif
2679#ifdef CONFIG_BRIDGE_NETFILTER
2680        nf_bridge_put(dst->nf_bridge);
2681#endif
2682        __nf_copy(dst, src);
2683}
2684
2685#ifdef CONFIG_NETWORK_SECMARK
2686static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2687{
2688        to->secmark = from->secmark;
2689}
2690
2691static inline void skb_init_secmark(struct sk_buff *skb)
2692{
2693        skb->secmark = 0;
2694}
2695#else
2696static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2697{ }
2698
2699static inline void skb_init_secmark(struct sk_buff *skb)
2700{ }
2701#endif
2702
2703static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2704{
2705        skb->queue_mapping = queue_mapping;
2706}
2707
2708static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2709{
2710        return skb->queue_mapping;
2711}
2712
2713static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2714{
2715        to->queue_mapping = from->queue_mapping;
2716}
2717
2718static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2719{
2720        skb->queue_mapping = rx_queue + 1;
2721}
2722
2723static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2724{
2725        return skb->queue_mapping - 1;
2726}
2727
2728static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2729{
2730        return skb->queue_mapping != 0;
2731}
2732
2733extern u16 __skb_tx_hash(const struct net_device *dev,
2734                         const struct sk_buff *skb,
2735                         unsigned int num_tx_queues);
2736
2737#ifdef CONFIG_XFRM
2738static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2739{
2740        return skb->sp;
2741}
2742#else
2743static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2744{
2745        return NULL;
2746}
2747#endif
2748
2749/* Keeps track of mac header offset relative to skb->head.
2750 * It is useful for TSO of Tunneling protocol. e.g. GRE.
2751 * For non-tunnel skb it points to skb_mac_header() and for
2752 * tunnel skb it points to outer mac header. */
2753struct skb_gso_cb {
2754        int mac_offset;
2755};
2756#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
2757
2758static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
2759{
2760        return (skb_mac_header(inner_skb) - inner_skb->head) -
2761                SKB_GSO_CB(inner_skb)->mac_offset;
2762}
2763
2764static inline bool skb_is_gso(const struct sk_buff *skb)
2765{
2766        return skb_shinfo(skb)->gso_size;
2767}
2768
2769static inline bool skb_is_gso_v6(const struct sk_buff *skb)
2770{
2771        return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2772}
2773
2774extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2775
2776static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2777{
2778        /* LRO sets gso_size but not gso_type, whereas if GSO is really
2779         * wanted then gso_type will be set. */
2780        const struct skb_shared_info *shinfo = skb_shinfo(skb);
2781
2782        if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2783            unlikely(shinfo->gso_type == 0)) {
2784                __skb_warn_lro_forwarding(skb);
2785                return true;
2786        }
2787        return false;
2788}
2789
2790static inline void skb_forward_csum(struct sk_buff *skb)
2791{
2792        /* Unfortunately we don't support this one.  Any brave souls? */
2793        if (skb->ip_summed == CHECKSUM_COMPLETE)
2794                skb->ip_summed = CHECKSUM_NONE;
2795}
2796
2797/**
2798 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2799 * @skb: skb to check
2800 *
2801 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2802 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2803 * use this helper, to document places where we make this assertion.
2804 */
2805static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2806{
2807#ifdef DEBUG
2808        BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2809#endif
2810}
2811
2812bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2813
2814/**
2815 * skb_head_is_locked - Determine if the skb->head is locked down
2816 * @skb: skb to check
2817 *
2818 * The head on skbs build around a head frag can be removed if they are
2819 * not cloned.  This function returns true if the skb head is locked down
2820 * due to either being allocated via kmalloc, or by being a clone with
2821 * multiple references to the head.
2822 */
2823static inline bool skb_head_is_locked(const struct sk_buff *skb)
2824{
2825        return !skb->head_frag || skb_cloned(skb);
2826}
2827#endif  /* __KERNEL__ */
2828#endif  /* _LINUX_SKBUFF_H */
2829
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