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