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Linux/include/linux/skbuff.h

  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 #include <linux/rbtree.h>
 24 #include <linux/socket.h>
 25 
 26 #include <linux/atomic.h>
 27 #include <asm/types.h>
 28 #include <linux/spinlock.h>
 29 #include <linux/net.h>
 30 #include <linux/textsearch.h>
 31 #include <net/checksum.h>
 32 #include <linux/rcupdate.h>
 33 #include <linux/hrtimer.h>
 34 #include <linux/dma-mapping.h>
 35 #include <linux/netdev_features.h>
 36 #include <linux/sched.h>
 37 #include <net/flow_dissector.h>
 38 #include <linux/splice.h>
 39 #include <linux/in6.h>
 40 #include <linux/if_packet.h>
 41 #include <net/flow.h>
 42 
 43 /* The interface for checksum offload between the stack and networking drivers
 44  * is as follows...
 45  *
 46  * A. IP checksum related features
 47  *
 48  * Drivers advertise checksum offload capabilities in the features of a device.
 49  * From the stack's point of view these are capabilities offered by the driver,
 50  * a driver typically only advertises features that it is capable of offloading
 51  * to its device.
 52  *
 53  * The checksum related features are:
 54  *
 55  *      NETIF_F_HW_CSUM - The driver (or its device) is able to compute one
 56  *                        IP (one's complement) checksum for any combination
 57  *                        of protocols or protocol layering. The checksum is
 58  *                        computed and set in a packet per the CHECKSUM_PARTIAL
 59  *                        interface (see below).
 60  *
 61  *      NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain
 62  *                        TCP or UDP packets over IPv4. These are specifically
 63  *                        unencapsulated packets of the form IPv4|TCP or
 64  *                        IPv4|UDP where the Protocol field in the IPv4 header
 65  *                        is TCP or UDP. The IPv4 header may contain IP options
 66  *                        This feature cannot be set in features for a device
 67  *                        with NETIF_F_HW_CSUM also set. This feature is being
 68  *                        DEPRECATED (see below).
 69  *
 70  *      NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain
 71  *                        TCP or UDP packets over IPv6. These are specifically
 72  *                        unencapsulated packets of the form IPv6|TCP or
 73  *                        IPv4|UDP where the Next Header field in the IPv6
 74  *                        header is either TCP or UDP. IPv6 extension headers
 75  *                        are not supported with this feature. This feature
 76  *                        cannot be set in features for a device with
 77  *                        NETIF_F_HW_CSUM also set. This feature is being
 78  *                        DEPRECATED (see below).
 79  *
 80  *      NETIF_F_RXCSUM - Driver (device) performs receive checksum offload.
 81  *                       This flag is used only used to disable the RX checksum
 82  *                       feature for a device. The stack will accept receive
 83  *                       checksum indication in packets received on a device
 84  *                       regardless of whether NETIF_F_RXCSUM is set.
 85  *
 86  * B. Checksumming of received packets by device. Indication of checksum
 87  *    verification is in set skb->ip_summed. Possible values are:
 88  *
 89  * CHECKSUM_NONE:
 90  *
 91  *   Device did not checksum this packet e.g. due to lack of capabilities.
 92  *   The packet contains full (though not verified) checksum in packet but
 93  *   not in skb->csum. Thus, skb->csum is undefined in this case.
 94  *
 95  * CHECKSUM_UNNECESSARY:
 96  *
 97  *   The hardware you're dealing with doesn't calculate the full checksum
 98  *   (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
 99  *   for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
100  *   if their checksums are okay. skb->csum is still undefined in this case
101  *   though. A driver or device must never modify the checksum field in the
102  *   packet even if checksum is verified.
103  *
104  *   CHECKSUM_UNNECESSARY is applicable to following protocols:
105  *     TCP: IPv6 and IPv4.
106  *     UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
107  *       zero UDP checksum for either IPv4 or IPv6, the networking stack
108  *       may perform further validation in this case.
109  *     GRE: only if the checksum is present in the header.
110  *     SCTP: indicates the CRC in SCTP header has been validated.
111  *
112  *   skb->csum_level indicates the number of consecutive checksums found in
113  *   the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
114  *   For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
115  *   and a device is able to verify the checksums for UDP (possibly zero),
116  *   GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
117  *   two. If the device were only able to verify the UDP checksum and not
118  *   GRE, either because it doesn't support GRE checksum of because GRE
119  *   checksum is bad, skb->csum_level would be set to zero (TCP checksum is
120  *   not considered in this case).
121  *
122  * CHECKSUM_COMPLETE:
123  *
124  *   This is the most generic way. The device supplied checksum of the _whole_
125  *   packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
126  *   hardware doesn't need to parse L3/L4 headers to implement this.
127  *
128  *   Note: Even if device supports only some protocols, but is able to produce
129  *   skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
130  *
131  * CHECKSUM_PARTIAL:
132  *
133  *   A checksum is set up to be offloaded to a device as described in the
134  *   output description for CHECKSUM_PARTIAL. This may occur on a packet
135  *   received directly from another Linux OS, e.g., a virtualized Linux kernel
136  *   on the same host, or it may be set in the input path in GRO or remote
137  *   checksum offload. For the purposes of checksum verification, the checksum
138  *   referred to by skb->csum_start + skb->csum_offset and any preceding
139  *   checksums in the packet are considered verified. Any checksums in the
140  *   packet that are after the checksum being offloaded are not considered to
141  *   be verified.
142  *
143  * C. Checksumming on transmit for non-GSO. The stack requests checksum offload
144  *    in the skb->ip_summed for a packet. Values are:
145  *
146  * CHECKSUM_PARTIAL:
147  *
148  *   The driver is required to checksum the packet as seen by hard_start_xmit()
149  *   from skb->csum_start up to the end, and to record/write the checksum at
150  *   offset skb->csum_start + skb->csum_offset. A driver may verify that the
151  *   csum_start and csum_offset values are valid values given the length and
152  *   offset of the packet, however they should not attempt to validate that the
153  *   checksum refers to a legitimate transport layer checksum-- it is the
154  *   purview of the stack to validate that csum_start and csum_offset are set
155  *   correctly.
156  *
157  *   When the stack requests checksum offload for a packet, the driver MUST
158  *   ensure that the checksum is set correctly. A driver can either offload the
159  *   checksum calculation to the device, or call skb_checksum_help (in the case
160  *   that the device does not support offload for a particular checksum).
161  *
162  *   NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of
163  *   NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate
164  *   checksum offload capability. If a  device has limited checksum capabilities
165  *   (for instance can only perform NETIF_F_IP_CSUM or NETIF_F_IPV6_CSUM as
166  *   described above) a helper function can be called to resolve
167  *   CHECKSUM_PARTIAL. The helper functions are skb_csum_off_chk*. The helper
168  *   function takes a spec argument that describes the protocol layer that is
169  *   supported for checksum offload and can be called for each packet. If a
170  *   packet does not match the specification for offload, skb_checksum_help
171  *   is called to resolve the checksum.
172  *
173  * CHECKSUM_NONE:
174  *
175  *   The skb was already checksummed by the protocol, or a checksum is not
176  *   required.
177  *
178  * CHECKSUM_UNNECESSARY:
179  *
180  *   This has the same meaning on as CHECKSUM_NONE for checksum offload on
181  *   output.
182  *
183  * CHECKSUM_COMPLETE:
184  *   Not used in checksum output. If a driver observes a packet with this value
185  *   set in skbuff, if should treat as CHECKSUM_NONE being set.
186  *
187  * D. Non-IP checksum (CRC) offloads
188  *
189  *   NETIF_F_SCTP_CRC - This feature indicates that a device is capable of
190  *     offloading the SCTP CRC in a packet. To perform this offload the stack
191  *     will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
192  *     accordingly. Note the there is no indication in the skbuff that the
193  *     CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports
194  *     both IP checksum offload and SCTP CRC offload must verify which offload
195  *     is configured for a packet presumably by inspecting packet headers.
196  *
197  *   NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
198  *     offloading the FCOE CRC in a packet. To perform this offload the stack
199  *     will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
200  *     accordingly. Note the there is no indication in the skbuff that the
201  *     CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports
202  *     both IP checksum offload and FCOE CRC offload must verify which offload
203  *     is configured for a packet presumably by inspecting packet headers.
204  *
205  * E. Checksumming on output with GSO.
206  *
207  * In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload
208  * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
209  * gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as
210  * part of the GSO operation is implied. If a checksum is being offloaded
211  * with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset
212  * are set to refer to the outermost checksum being offload (two offloaded
213  * checksums are possible with UDP encapsulation).
214  */
215 
216 /* Don't change this without changing skb_csum_unnecessary! */
217 #define CHECKSUM_NONE           0
218 #define CHECKSUM_UNNECESSARY    1
219 #define CHECKSUM_COMPLETE       2
220 #define CHECKSUM_PARTIAL        3
221 
222 /* Maximum value in skb->csum_level */
223 #define SKB_MAX_CSUM_LEVEL      3
224 
225 #define SKB_DATA_ALIGN(X)       ALIGN(X, SMP_CACHE_BYTES)
226 #define SKB_WITH_OVERHEAD(X)    \
227         ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
228 #define SKB_MAX_ORDER(X, ORDER) \
229         SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
230 #define SKB_MAX_HEAD(X)         (SKB_MAX_ORDER((X), 0))
231 #define SKB_MAX_ALLOC           (SKB_MAX_ORDER(0, 2))
232 
233 /* return minimum truesize of one skb containing X bytes of data */
234 #define SKB_TRUESIZE(X) ((X) +                                          \
235                          SKB_DATA_ALIGN(sizeof(struct sk_buff)) +       \
236                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
237 
238 struct net_device;
239 struct scatterlist;
240 struct pipe_inode_info;
241 struct iov_iter;
242 struct napi_struct;
243 
244 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
245 struct nf_conntrack {
246         atomic_t use;
247 };
248 #endif
249 
250 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
251 struct nf_bridge_info {
252         atomic_t                use;
253         enum {
254                 BRNF_PROTO_UNCHANGED,
255                 BRNF_PROTO_8021Q,
256                 BRNF_PROTO_PPPOE
257         } orig_proto:8;
258         u8                      pkt_otherhost:1;
259         u8                      in_prerouting:1;
260         u8                      bridged_dnat:1;
261         __u16                   frag_max_size;
262         struct net_device       *physindev;
263 
264         /* always valid & non-NULL from FORWARD on, for physdev match */
265         struct net_device       *physoutdev;
266         union {
267                 /* prerouting: detect dnat in orig/reply direction */
268                 __be32          ipv4_daddr;
269                 struct in6_addr ipv6_daddr;
270 
271                 /* after prerouting + nat detected: store original source
272                  * mac since neigh resolution overwrites it, only used while
273                  * skb is out in neigh layer.
274                  */
275                 char neigh_header[8];
276         };
277 };
278 #endif
279 
280 struct sk_buff_head {
281         /* These two members must be first. */
282         struct sk_buff  *next;
283         struct sk_buff  *prev;
284 
285         __u32           qlen;
286         spinlock_t      lock;
287 };
288 
289 struct sk_buff;
290 
291 /* To allow 64K frame to be packed as single skb without frag_list we
292  * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
293  * buffers which do not start on a page boundary.
294  *
295  * Since GRO uses frags we allocate at least 16 regardless of page
296  * size.
297  */
298 #if (65536/PAGE_SIZE + 1) < 16
299 #define MAX_SKB_FRAGS 16UL
300 #else
301 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
302 #endif
303 extern int sysctl_max_skb_frags;
304 
305 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
306  * segment using its current segmentation instead.
307  */
308 #define GSO_BY_FRAGS    0xFFFF
309 
310 typedef struct skb_frag_struct skb_frag_t;
311 
312 struct skb_frag_struct {
313         struct {
314                 struct page *p;
315         } page;
316 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
317         __u32 page_offset;
318         __u32 size;
319 #else
320         __u16 page_offset;
321         __u16 size;
322 #endif
323 };
324 
325 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
326 {
327         return frag->size;
328 }
329 
330 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
331 {
332         frag->size = size;
333 }
334 
335 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
336 {
337         frag->size += delta;
338 }
339 
340 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
341 {
342         frag->size -= delta;
343 }
344 
345 #define HAVE_HW_TIME_STAMP
346 
347 /**
348  * struct skb_shared_hwtstamps - hardware time stamps
349  * @hwtstamp:   hardware time stamp transformed into duration
350  *              since arbitrary point in time
351  *
352  * Software time stamps generated by ktime_get_real() are stored in
353  * skb->tstamp.
354  *
355  * hwtstamps can only be compared against other hwtstamps from
356  * the same device.
357  *
358  * This structure is attached to packets as part of the
359  * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
360  */
361 struct skb_shared_hwtstamps {
362         ktime_t hwtstamp;
363 };
364 
365 /* Definitions for tx_flags in struct skb_shared_info */
366 enum {
367         /* generate hardware time stamp */
368         SKBTX_HW_TSTAMP = 1 << 0,
369 
370         /* generate software time stamp when queueing packet to NIC */
371         SKBTX_SW_TSTAMP = 1 << 1,
372 
373         /* device driver is going to provide hardware time stamp */
374         SKBTX_IN_PROGRESS = 1 << 2,
375 
376         /* device driver supports TX zero-copy buffers */
377         SKBTX_DEV_ZEROCOPY = 1 << 3,
378 
379         /* generate wifi status information (where possible) */
380         SKBTX_WIFI_STATUS = 1 << 4,
381 
382         /* This indicates at least one fragment might be overwritten
383          * (as in vmsplice(), sendfile() ...)
384          * If we need to compute a TX checksum, we'll need to copy
385          * all frags to avoid possible bad checksum
386          */
387         SKBTX_SHARED_FRAG = 1 << 5,
388 
389         /* generate software time stamp when entering packet scheduling */
390         SKBTX_SCHED_TSTAMP = 1 << 6,
391 };
392 
393 #define SKBTX_ANY_SW_TSTAMP     (SKBTX_SW_TSTAMP    | \
394                                  SKBTX_SCHED_TSTAMP)
395 #define SKBTX_ANY_TSTAMP        (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
396 
397 /*
398  * The callback notifies userspace to release buffers when skb DMA is done in
399  * lower device, the skb last reference should be 0 when calling this.
400  * The zerocopy_success argument is true if zero copy transmit occurred,
401  * false on data copy or out of memory error caused by data copy attempt.
402  * The ctx field is used to track device context.
403  * The desc field is used to track userspace buffer index.
404  */
405 struct ubuf_info {
406         void (*callback)(struct ubuf_info *, bool zerocopy_success);
407         void *ctx;
408         unsigned long desc;
409 };
410 
411 /* This data is invariant across clones and lives at
412  * the end of the header data, ie. at skb->end.
413  */
414 struct skb_shared_info {
415         unsigned char   nr_frags;
416         __u8            tx_flags;
417         unsigned short  gso_size;
418         /* Warning: this field is not always filled in (UFO)! */
419         unsigned short  gso_segs;
420         unsigned short  gso_type;
421         struct sk_buff  *frag_list;
422         struct skb_shared_hwtstamps hwtstamps;
423         u32             tskey;
424         __be32          ip6_frag_id;
425 
426         /*
427          * Warning : all fields before dataref are cleared in __alloc_skb()
428          */
429         atomic_t        dataref;
430 
431         /* Intermediate layers must ensure that destructor_arg
432          * remains valid until skb destructor */
433         void *          destructor_arg;
434 
435         /* must be last field, see pskb_expand_head() */
436         skb_frag_t      frags[MAX_SKB_FRAGS];
437 };
438 
439 /* We divide dataref into two halves.  The higher 16 bits hold references
440  * to the payload part of skb->data.  The lower 16 bits hold references to
441  * the entire skb->data.  A clone of a headerless skb holds the length of
442  * the header in skb->hdr_len.
443  *
444  * All users must obey the rule that the skb->data reference count must be
445  * greater than or equal to the payload reference count.
446  *
447  * Holding a reference to the payload part means that the user does not
448  * care about modifications to the header part of skb->data.
449  */
450 #define SKB_DATAREF_SHIFT 16
451 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
452 
453 
454 enum {
455         SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
456         SKB_FCLONE_ORIG,        /* orig skb (from fclone_cache) */
457         SKB_FCLONE_CLONE,       /* companion fclone skb (from fclone_cache) */
458 };
459 
460 enum {
461         SKB_GSO_TCPV4 = 1 << 0,
462         SKB_GSO_UDP = 1 << 1,
463 
464         /* This indicates the skb is from an untrusted source. */
465         SKB_GSO_DODGY = 1 << 2,
466 
467         /* This indicates the tcp segment has CWR set. */
468         SKB_GSO_TCP_ECN = 1 << 3,
469 
470         SKB_GSO_TCP_FIXEDID = 1 << 4,
471 
472         SKB_GSO_TCPV6 = 1 << 5,
473 
474         SKB_GSO_FCOE = 1 << 6,
475 
476         SKB_GSO_GRE = 1 << 7,
477 
478         SKB_GSO_GRE_CSUM = 1 << 8,
479 
480         SKB_GSO_IPXIP4 = 1 << 9,
481 
482         SKB_GSO_IPXIP6 = 1 << 10,
483 
484         SKB_GSO_UDP_TUNNEL = 1 << 11,
485 
486         SKB_GSO_UDP_TUNNEL_CSUM = 1 << 12,
487 
488         SKB_GSO_PARTIAL = 1 << 13,
489 
490         SKB_GSO_TUNNEL_REMCSUM = 1 << 14,
491 
492         SKB_GSO_SCTP = 1 << 15,
493 };
494 
495 #if BITS_PER_LONG > 32
496 #define NET_SKBUFF_DATA_USES_OFFSET 1
497 #endif
498 
499 #ifdef NET_SKBUFF_DATA_USES_OFFSET
500 typedef unsigned int sk_buff_data_t;
501 #else
502 typedef unsigned char *sk_buff_data_t;
503 #endif
504 
505 /**
506  * struct skb_mstamp - multi resolution time stamps
507  * @stamp_us: timestamp in us resolution
508  * @stamp_jiffies: timestamp in jiffies
509  */
510 struct skb_mstamp {
511         union {
512                 u64             v64;
513                 struct {
514                         u32     stamp_us;
515                         u32     stamp_jiffies;
516                 };
517         };
518 };
519 
520 /**
521  * skb_mstamp_get - get current timestamp
522  * @cl: place to store timestamps
523  */
524 static inline void skb_mstamp_get(struct skb_mstamp *cl)
525 {
526         u64 val = local_clock();
527 
528         do_div(val, NSEC_PER_USEC);
529         cl->stamp_us = (u32)val;
530         cl->stamp_jiffies = (u32)jiffies;
531 }
532 
533 /**
534  * skb_mstamp_delta - compute the difference in usec between two skb_mstamp
535  * @t1: pointer to newest sample
536  * @t0: pointer to oldest sample
537  */
538 static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
539                                       const struct skb_mstamp *t0)
540 {
541         s32 delta_us = t1->stamp_us - t0->stamp_us;
542         u32 delta_jiffies = t1->stamp_jiffies - t0->stamp_jiffies;
543 
544         /* If delta_us is negative, this might be because interval is too big,
545          * or local_clock() drift is too big : fallback using jiffies.
546          */
547         if (delta_us <= 0 ||
548             delta_jiffies >= (INT_MAX / (USEC_PER_SEC / HZ)))
549 
550                 delta_us = jiffies_to_usecs(delta_jiffies);
551 
552         return delta_us;
553 }
554 
555 static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
556                                     const struct skb_mstamp *t0)
557 {
558         s32 diff = t1->stamp_jiffies - t0->stamp_jiffies;
559 
560         if (!diff)
561                 diff = t1->stamp_us - t0->stamp_us;
562         return diff > 0;
563 }
564 
565 /** 
566  *      struct sk_buff - socket buffer
567  *      @next: Next buffer in list
568  *      @prev: Previous buffer in list
569  *      @tstamp: Time we arrived/left
570  *      @rbnode: RB tree node, alternative to next/prev for netem/tcp
571  *      @sk: Socket we are owned by
572  *      @dev: Device we arrived on/are leaving by
573  *      @cb: Control buffer. Free for use by every layer. Put private vars here
574  *      @_skb_refdst: destination entry (with norefcount bit)
575  *      @sp: the security path, used for xfrm
576  *      @len: Length of actual data
577  *      @data_len: Data length
578  *      @mac_len: Length of link layer header
579  *      @hdr_len: writable header length of cloned skb
580  *      @csum: Checksum (must include start/offset pair)
581  *      @csum_start: Offset from skb->head where checksumming should start
582  *      @csum_offset: Offset from csum_start where checksum should be stored
583  *      @priority: Packet queueing priority
584  *      @ignore_df: allow local fragmentation
585  *      @cloned: Head may be cloned (check refcnt to be sure)
586  *      @ip_summed: Driver fed us an IP checksum
587  *      @nohdr: Payload reference only, must not modify header
588  *      @nfctinfo: Relationship of this skb to the connection
589  *      @pkt_type: Packet class
590  *      @fclone: skbuff clone status
591  *      @ipvs_property: skbuff is owned by ipvs
592  *      @peeked: this packet has been seen already, so stats have been
593  *              done for it, don't do them again
594  *      @nf_trace: netfilter packet trace flag
595  *      @protocol: Packet protocol from driver
596  *      @destructor: Destruct function
597  *      @nfct: Associated connection, if any
598  *      @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
599  *      @skb_iif: ifindex of device we arrived on
600  *      @tc_index: Traffic control index
601  *      @tc_verd: traffic control verdict
602  *      @hash: the packet hash
603  *      @queue_mapping: Queue mapping for multiqueue devices
604  *      @xmit_more: More SKBs are pending for this queue
605  *      @ndisc_nodetype: router type (from link layer)
606  *      @ooo_okay: allow the mapping of a socket to a queue to be changed
607  *      @l4_hash: indicate hash is a canonical 4-tuple hash over transport
608  *              ports.
609  *      @sw_hash: indicates hash was computed in software stack
610  *      @wifi_acked_valid: wifi_acked was set
611  *      @wifi_acked: whether frame was acked on wifi or not
612  *      @no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
613   *     @napi_id: id of the NAPI struct this skb came from
614  *      @secmark: security marking
615  *      @mark: Generic packet mark
616  *      @vlan_proto: vlan encapsulation protocol
617  *      @vlan_tci: vlan tag control information
618  *      @inner_protocol: Protocol (encapsulation)
619  *      @inner_transport_header: Inner transport layer header (encapsulation)
620  *      @inner_network_header: Network layer header (encapsulation)
621  *      @inner_mac_header: Link layer header (encapsulation)
622  *      @transport_header: Transport layer header
623  *      @network_header: Network layer header
624  *      @mac_header: Link layer header
625  *      @tail: Tail pointer
626  *      @end: End pointer
627  *      @head: Head of buffer
628  *      @data: Data head pointer
629  *      @truesize: Buffer size
630  *      @users: User count - see {datagram,tcp}.c
631  */
632 
633 struct sk_buff {
634         union {
635                 struct {
636                         /* These two members must be first. */
637                         struct sk_buff          *next;
638                         struct sk_buff          *prev;
639 
640                         union {
641                                 ktime_t         tstamp;
642                                 struct skb_mstamp skb_mstamp;
643                         };
644                 };
645                 struct rb_node  rbnode; /* used in netem & tcp stack */
646         };
647         struct sock             *sk;
648         struct net_device       *dev;
649 
650         /*
651          * This is the control buffer. It is free to use for every
652          * layer. Please put your private variables there. If you
653          * want to keep them across layers you have to do a skb_clone()
654          * first. This is owned by whoever has the skb queued ATM.
655          */
656         char                    cb[48] __aligned(8);
657 
658         unsigned long           _skb_refdst;
659         void                    (*destructor)(struct sk_buff *skb);
660 #ifdef CONFIG_XFRM
661         struct  sec_path        *sp;
662 #endif
663 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
664         struct nf_conntrack     *nfct;
665 #endif
666 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
667         struct nf_bridge_info   *nf_bridge;
668 #endif
669         unsigned int            len,
670                                 data_len;
671         __u16                   mac_len,
672                                 hdr_len;
673 
674         /* Following fields are _not_ copied in __copy_skb_header()
675          * Note that queue_mapping is here mostly to fill a hole.
676          */
677         kmemcheck_bitfield_begin(flags1);
678         __u16                   queue_mapping;
679 
680 /* if you move cloned around you also must adapt those constants */
681 #ifdef __BIG_ENDIAN_BITFIELD
682 #define CLONED_MASK     (1 << 7)
683 #else
684 #define CLONED_MASK     1
685 #endif
686 #define CLONED_OFFSET()         offsetof(struct sk_buff, __cloned_offset)
687 
688         __u8                    __cloned_offset[0];
689         __u8                    cloned:1,
690                                 nohdr:1,
691                                 fclone:2,
692                                 peeked:1,
693                                 head_frag:1,
694                                 xmit_more:1,
695                                 __unused:1; /* one bit hole */
696         kmemcheck_bitfield_end(flags1);
697 
698         /* fields enclosed in headers_start/headers_end are copied
699          * using a single memcpy() in __copy_skb_header()
700          */
701         /* private: */
702         __u32                   headers_start[0];
703         /* public: */
704 
705 /* if you move pkt_type around you also must adapt those constants */
706 #ifdef __BIG_ENDIAN_BITFIELD
707 #define PKT_TYPE_MAX    (7 << 5)
708 #else
709 #define PKT_TYPE_MAX    7
710 #endif
711 #define PKT_TYPE_OFFSET()       offsetof(struct sk_buff, __pkt_type_offset)
712 
713         __u8                    __pkt_type_offset[0];
714         __u8                    pkt_type:3;
715         __u8                    pfmemalloc:1;
716         __u8                    ignore_df:1;
717         __u8                    nfctinfo:3;
718 
719         __u8                    nf_trace:1;
720         __u8                    ip_summed:2;
721         __u8                    ooo_okay:1;
722         __u8                    l4_hash:1;
723         __u8                    sw_hash:1;
724         __u8                    wifi_acked_valid:1;
725         __u8                    wifi_acked:1;
726 
727         __u8                    no_fcs:1;
728         /* Indicates the inner headers are valid in the skbuff. */
729         __u8                    encapsulation:1;
730         __u8                    encap_hdr_csum:1;
731         __u8                    csum_valid:1;
732         __u8                    csum_complete_sw:1;
733         __u8                    csum_level:2;
734         __u8                    csum_bad:1;
735 
736 #ifdef CONFIG_IPV6_NDISC_NODETYPE
737         __u8                    ndisc_nodetype:2;
738 #endif
739         __u8                    ipvs_property:1;
740         __u8                    inner_protocol_type:1;
741         __u8                    remcsum_offload:1;
742 #ifdef CONFIG_NET_SWITCHDEV
743         __u8                    offload_fwd_mark:1;
744 #endif
745         /* 2, 4 or 5 bit hole */
746 
747 #ifdef CONFIG_NET_SCHED
748         __u16                   tc_index;       /* traffic control index */
749 #ifdef CONFIG_NET_CLS_ACT
750         __u16                   tc_verd;        /* traffic control verdict */
751 #endif
752 #endif
753 
754         union {
755                 __wsum          csum;
756                 struct {
757                         __u16   csum_start;
758                         __u16   csum_offset;
759                 };
760         };
761         __u32                   priority;
762         int                     skb_iif;
763         __u32                   hash;
764         __be16                  vlan_proto;
765         __u16                   vlan_tci;
766 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
767         union {
768                 unsigned int    napi_id;
769                 unsigned int    sender_cpu;
770         };
771 #endif
772 #ifdef CONFIG_NETWORK_SECMARK
773         __u32           secmark;
774 #endif
775 
776         union {
777                 __u32           mark;
778                 __u32           reserved_tailroom;
779         };
780 
781         union {
782                 __be16          inner_protocol;
783                 __u8            inner_ipproto;
784         };
785 
786         __u16                   inner_transport_header;
787         __u16                   inner_network_header;
788         __u16                   inner_mac_header;
789 
790         __be16                  protocol;
791         __u16                   transport_header;
792         __u16                   network_header;
793         __u16                   mac_header;
794 
795         /* private: */
796         __u32                   headers_end[0];
797         /* public: */
798 
799         /* These elements must be at the end, see alloc_skb() for details.  */
800         sk_buff_data_t          tail;
801         sk_buff_data_t          end;
802         unsigned char           *head,
803                                 *data;
804         unsigned int            truesize;
805         atomic_t                users;
806 };
807 
808 #ifdef __KERNEL__
809 /*
810  *      Handling routines are only of interest to the kernel
811  */
812 #include <linux/slab.h>
813 
814 
815 #define SKB_ALLOC_FCLONE        0x01
816 #define SKB_ALLOC_RX            0x02
817 #define SKB_ALLOC_NAPI          0x04
818 
819 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
820 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
821 {
822         return unlikely(skb->pfmemalloc);
823 }
824 
825 /*
826  * skb might have a dst pointer attached, refcounted or not.
827  * _skb_refdst low order bit is set if refcount was _not_ taken
828  */
829 #define SKB_DST_NOREF   1UL
830 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
831 
832 /**
833  * skb_dst - returns skb dst_entry
834  * @skb: buffer
835  *
836  * Returns skb dst_entry, regardless of reference taken or not.
837  */
838 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
839 {
840         /* If refdst was not refcounted, check we still are in a 
841          * rcu_read_lock section
842          */
843         WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
844                 !rcu_read_lock_held() &&
845                 !rcu_read_lock_bh_held());
846         return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
847 }
848 
849 /**
850  * skb_dst_set - sets skb dst
851  * @skb: buffer
852  * @dst: dst entry
853  *
854  * Sets skb dst, assuming a reference was taken on dst and should
855  * be released by skb_dst_drop()
856  */
857 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
858 {
859         skb->_skb_refdst = (unsigned long)dst;
860 }
861 
862 /**
863  * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
864  * @skb: buffer
865  * @dst: dst entry
866  *
867  * Sets skb dst, assuming a reference was not taken on dst.
868  * If dst entry is cached, we do not take reference and dst_release
869  * will be avoided by refdst_drop. If dst entry is not cached, we take
870  * reference, so that last dst_release can destroy the dst immediately.
871  */
872 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
873 {
874         WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
875         skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
876 }
877 
878 /**
879  * skb_dst_is_noref - Test if skb dst isn't refcounted
880  * @skb: buffer
881  */
882 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
883 {
884         return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
885 }
886 
887 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
888 {
889         return (struct rtable *)skb_dst(skb);
890 }
891 
892 /* For mangling skb->pkt_type from user space side from applications
893  * such as nft, tc, etc, we only allow a conservative subset of
894  * possible pkt_types to be set.
895 */
896 static inline bool skb_pkt_type_ok(u32 ptype)
897 {
898         return ptype <= PACKET_OTHERHOST;
899 }
900 
901 void kfree_skb(struct sk_buff *skb);
902 void kfree_skb_list(struct sk_buff *segs);
903 void skb_tx_error(struct sk_buff *skb);
904 void consume_skb(struct sk_buff *skb);
905 void  __kfree_skb(struct sk_buff *skb);
906 extern struct kmem_cache *skbuff_head_cache;
907 
908 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
909 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
910                       bool *fragstolen, int *delta_truesize);
911 
912 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
913                             int node);
914 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
915 struct sk_buff *build_skb(void *data, unsigned int frag_size);
916 static inline struct sk_buff *alloc_skb(unsigned int size,
917                                         gfp_t priority)
918 {
919         return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
920 }
921 
922 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
923                                      unsigned long data_len,
924                                      int max_page_order,
925                                      int *errcode,
926                                      gfp_t gfp_mask);
927 
928 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
929 struct sk_buff_fclones {
930         struct sk_buff  skb1;
931 
932         struct sk_buff  skb2;
933 
934         atomic_t        fclone_ref;
935 };
936 
937 /**
938  *      skb_fclone_busy - check if fclone is busy
939  *      @sk: socket
940  *      @skb: buffer
941  *
942  * Returns true if skb is a fast clone, and its clone is not freed.
943  * Some drivers call skb_orphan() in their ndo_start_xmit(),
944  * so we also check that this didnt happen.
945  */
946 static inline bool skb_fclone_busy(const struct sock *sk,
947                                    const struct sk_buff *skb)
948 {
949         const struct sk_buff_fclones *fclones;
950 
951         fclones = container_of(skb, struct sk_buff_fclones, skb1);
952 
953         return skb->fclone == SKB_FCLONE_ORIG &&
954                atomic_read(&fclones->fclone_ref) > 1 &&
955                fclones->skb2.sk == sk;
956 }
957 
958 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
959                                                gfp_t priority)
960 {
961         return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
962 }
963 
964 struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
965 static inline struct sk_buff *alloc_skb_head(gfp_t priority)
966 {
967         return __alloc_skb_head(priority, -1);
968 }
969 
970 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
971 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
972 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
973 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
974 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
975                                    gfp_t gfp_mask, bool fclone);
976 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
977                                           gfp_t gfp_mask)
978 {
979         return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
980 }
981 
982 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
983 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
984                                      unsigned int headroom);
985 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
986                                 int newtailroom, gfp_t priority);
987 int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
988                         int offset, int len);
989 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
990                  int len);
991 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
992 int skb_pad(struct sk_buff *skb, int pad);
993 #define dev_kfree_skb(a)        consume_skb(a)
994 
995 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
996                             int getfrag(void *from, char *to, int offset,
997                                         int len, int odd, struct sk_buff *skb),
998                             void *from, int length);
999 
1000 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1001                          int offset, size_t size);
1002 
1003 struct skb_seq_state {
1004         __u32           lower_offset;
1005         __u32           upper_offset;
1006         __u32           frag_idx;
1007         __u32           stepped_offset;
1008         struct sk_buff  *root_skb;
1009         struct sk_buff  *cur_skb;
1010         __u8            *frag_data;
1011 };
1012 
1013 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1014                           unsigned int to, struct skb_seq_state *st);
1015 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1016                           struct skb_seq_state *st);
1017 void skb_abort_seq_read(struct skb_seq_state *st);
1018 
1019 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1020                            unsigned int to, struct ts_config *config);
1021 
1022 /*
1023  * Packet hash types specify the type of hash in skb_set_hash.
1024  *
1025  * Hash types refer to the protocol layer addresses which are used to
1026  * construct a packet's hash. The hashes are used to differentiate or identify
1027  * flows of the protocol layer for the hash type. Hash types are either
1028  * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1029  *
1030  * Properties of hashes:
1031  *
1032  * 1) Two packets in different flows have different hash values
1033  * 2) Two packets in the same flow should have the same hash value
1034  *
1035  * A hash at a higher layer is considered to be more specific. A driver should
1036  * set the most specific hash possible.
1037  *
1038  * A driver cannot indicate a more specific hash than the layer at which a hash
1039  * was computed. For instance an L3 hash cannot be set as an L4 hash.
1040  *
1041  * A driver may indicate a hash level which is less specific than the
1042  * actual layer the hash was computed on. For instance, a hash computed
1043  * at L4 may be considered an L3 hash. This should only be done if the
1044  * driver can't unambiguously determine that the HW computed the hash at
1045  * the higher layer. Note that the "should" in the second property above
1046  * permits this.
1047  */
1048 enum pkt_hash_types {
1049         PKT_HASH_TYPE_NONE,     /* Undefined type */
1050         PKT_HASH_TYPE_L2,       /* Input: src_MAC, dest_MAC */
1051         PKT_HASH_TYPE_L3,       /* Input: src_IP, dst_IP */
1052         PKT_HASH_TYPE_L4,       /* Input: src_IP, dst_IP, src_port, dst_port */
1053 };
1054 
1055 static inline void skb_clear_hash(struct sk_buff *skb)
1056 {
1057         skb->hash = 0;
1058         skb->sw_hash = 0;
1059         skb->l4_hash = 0;
1060 }
1061 
1062 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1063 {
1064         if (!skb->l4_hash)
1065                 skb_clear_hash(skb);
1066 }
1067 
1068 static inline void
1069 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1070 {
1071         skb->l4_hash = is_l4;
1072         skb->sw_hash = is_sw;
1073         skb->hash = hash;
1074 }
1075 
1076 static inline void
1077 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1078 {
1079         /* Used by drivers to set hash from HW */
1080         __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1081 }
1082 
1083 static inline void
1084 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1085 {
1086         __skb_set_hash(skb, hash, true, is_l4);
1087 }
1088 
1089 void __skb_get_hash(struct sk_buff *skb);
1090 u32 __skb_get_hash_symmetric(struct sk_buff *skb);
1091 u32 skb_get_poff(const struct sk_buff *skb);
1092 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1093                    const struct flow_keys *keys, int hlen);
1094 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1095                             void *data, int hlen_proto);
1096 
1097 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1098                                         int thoff, u8 ip_proto)
1099 {
1100         return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1101 }
1102 
1103 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1104                              const struct flow_dissector_key *key,
1105                              unsigned int key_count);
1106 
1107 bool __skb_flow_dissect(const struct sk_buff *skb,
1108                         struct flow_dissector *flow_dissector,
1109                         void *target_container,
1110                         void *data, __be16 proto, int nhoff, int hlen,
1111                         unsigned int flags);
1112 
1113 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1114                                     struct flow_dissector *flow_dissector,
1115                                     void *target_container, unsigned int flags)
1116 {
1117         return __skb_flow_dissect(skb, flow_dissector, target_container,
1118                                   NULL, 0, 0, 0, flags);
1119 }
1120 
1121 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1122                                               struct flow_keys *flow,
1123                                               unsigned int flags)
1124 {
1125         memset(flow, 0, sizeof(*flow));
1126         return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
1127                                   NULL, 0, 0, 0, flags);
1128 }
1129 
1130 static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
1131                                                   void *data, __be16 proto,
1132                                                   int nhoff, int hlen,
1133                                                   unsigned int flags)
1134 {
1135         memset(flow, 0, sizeof(*flow));
1136         return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
1137                                   data, proto, nhoff, hlen, flags);
1138 }
1139 
1140 static inline __u32 skb_get_hash(struct sk_buff *skb)
1141 {
1142         if (!skb->l4_hash && !skb->sw_hash)
1143                 __skb_get_hash(skb);
1144 
1145         return skb->hash;
1146 }
1147 
1148 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6);
1149 
1150 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1151 {
1152         if (!skb->l4_hash && !skb->sw_hash) {
1153                 struct flow_keys keys;
1154                 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1155 
1156                 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1157         }
1158 
1159         return skb->hash;
1160 }
1161 
1162 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl);
1163 
1164 static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
1165 {
1166         if (!skb->l4_hash && !skb->sw_hash) {
1167                 struct flow_keys keys;
1168                 __u32 hash = __get_hash_from_flowi4(fl4, &keys);
1169 
1170                 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1171         }
1172 
1173         return skb->hash;
1174 }
1175 
1176 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1177 
1178 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1179 {
1180         return skb->hash;
1181 }
1182 
1183 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1184 {
1185         to->hash = from->hash;
1186         to->sw_hash = from->sw_hash;
1187         to->l4_hash = from->l4_hash;
1188 };
1189 
1190 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1191 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1192 {
1193         return skb->head + skb->end;
1194 }
1195 
1196 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1197 {
1198         return skb->end;
1199 }
1200 #else
1201 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1202 {
1203         return skb->end;
1204 }
1205 
1206 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1207 {
1208         return skb->end - skb->head;
1209 }
1210 #endif
1211 
1212 /* Internal */
1213 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1214 
1215 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1216 {
1217         return &skb_shinfo(skb)->hwtstamps;
1218 }
1219 
1220 /**
1221  *      skb_queue_empty - check if a queue is empty
1222  *      @list: queue head
1223  *
1224  *      Returns true if the queue is empty, false otherwise.
1225  */
1226 static inline int skb_queue_empty(const struct sk_buff_head *list)
1227 {
1228         return list->next == (const struct sk_buff *) list;
1229 }
1230 
1231 /**
1232  *      skb_queue_is_last - check if skb is the last entry in the queue
1233  *      @list: queue head
1234  *      @skb: buffer
1235  *
1236  *      Returns true if @skb is the last buffer on the list.
1237  */
1238 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1239                                      const struct sk_buff *skb)
1240 {
1241         return skb->next == (const struct sk_buff *) list;
1242 }
1243 
1244 /**
1245  *      skb_queue_is_first - check if skb is the first entry in the queue
1246  *      @list: queue head
1247  *      @skb: buffer
1248  *
1249  *      Returns true if @skb is the first buffer on the list.
1250  */
1251 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1252                                       const struct sk_buff *skb)
1253 {
1254         return skb->prev == (const struct sk_buff *) list;
1255 }
1256 
1257 /**
1258  *      skb_queue_next - return the next packet in the queue
1259  *      @list: queue head
1260  *      @skb: current buffer
1261  *
1262  *      Return the next packet in @list after @skb.  It is only valid to
1263  *      call this if skb_queue_is_last() evaluates to false.
1264  */
1265 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1266                                              const struct sk_buff *skb)
1267 {
1268         /* This BUG_ON may seem severe, but if we just return then we
1269          * are going to dereference garbage.
1270          */
1271         BUG_ON(skb_queue_is_last(list, skb));
1272         return skb->next;
1273 }
1274 
1275 /**
1276  *      skb_queue_prev - return the prev packet in the queue
1277  *      @list: queue head
1278  *      @skb: current buffer
1279  *
1280  *      Return the prev packet in @list before @skb.  It is only valid to
1281  *      call this if skb_queue_is_first() evaluates to false.
1282  */
1283 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1284                                              const struct sk_buff *skb)
1285 {
1286         /* This BUG_ON may seem severe, but if we just return then we
1287          * are going to dereference garbage.
1288          */
1289         BUG_ON(skb_queue_is_first(list, skb));
1290         return skb->prev;
1291 }
1292 
1293 /**
1294  *      skb_get - reference buffer
1295  *      @skb: buffer to reference
1296  *
1297  *      Makes another reference to a socket buffer and returns a pointer
1298  *      to the buffer.
1299  */
1300 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1301 {
1302         atomic_inc(&skb->users);
1303         return skb;
1304 }
1305 
1306 /*
1307  * If users == 1, we are the only owner and are can avoid redundant
1308  * atomic change.
1309  */
1310 
1311 /**
1312  *      skb_cloned - is the buffer a clone
1313  *      @skb: buffer to check
1314  *
1315  *      Returns true if the buffer was generated with skb_clone() and is
1316  *      one of multiple shared copies of the buffer. Cloned buffers are
1317  *      shared data so must not be written to under normal circumstances.
1318  */
1319 static inline int skb_cloned(const struct sk_buff *skb)
1320 {
1321         return skb->cloned &&
1322                (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1323 }
1324 
1325 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1326 {
1327         might_sleep_if(gfpflags_allow_blocking(pri));
1328 
1329         if (skb_cloned(skb))
1330                 return pskb_expand_head(skb, 0, 0, pri);
1331 
1332         return 0;
1333 }
1334 
1335 /**
1336  *      skb_header_cloned - is the header a clone
1337  *      @skb: buffer to check
1338  *
1339  *      Returns true if modifying the header part of the buffer requires
1340  *      the data to be copied.
1341  */
1342 static inline int skb_header_cloned(const struct sk_buff *skb)
1343 {
1344         int dataref;
1345 
1346         if (!skb->cloned)
1347                 return 0;
1348 
1349         dataref = atomic_read(&skb_shinfo(skb)->dataref);
1350         dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1351         return dataref != 1;
1352 }
1353 
1354 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
1355 {
1356         might_sleep_if(gfpflags_allow_blocking(pri));
1357 
1358         if (skb_header_cloned(skb))
1359                 return pskb_expand_head(skb, 0, 0, pri);
1360 
1361         return 0;
1362 }
1363 
1364 /**
1365  *      skb_header_release - release reference to header
1366  *      @skb: buffer to operate on
1367  *
1368  *      Drop a reference to the header part of the buffer.  This is done
1369  *      by acquiring a payload reference.  You must not read from the header
1370  *      part of skb->data after this.
1371  *      Note : Check if you can use __skb_header_release() instead.
1372  */
1373 static inline void skb_header_release(struct sk_buff *skb)
1374 {
1375         BUG_ON(skb->nohdr);
1376         skb->nohdr = 1;
1377         atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
1378 }
1379 
1380 /**
1381  *      __skb_header_release - release reference to header
1382  *      @skb: buffer to operate on
1383  *
1384  *      Variant of skb_header_release() assuming skb is private to caller.
1385  *      We can avoid one atomic operation.
1386  */
1387 static inline void __skb_header_release(struct sk_buff *skb)
1388 {
1389         skb->nohdr = 1;
1390         atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1391 }
1392 
1393 
1394 /**
1395  *      skb_shared - is the buffer shared
1396  *      @skb: buffer to check
1397  *
1398  *      Returns true if more than one person has a reference to this
1399  *      buffer.
1400  */
1401 static inline int skb_shared(const struct sk_buff *skb)
1402 {
1403         return atomic_read(&skb->users) != 1;
1404 }
1405 
1406 /**
1407  *      skb_share_check - check if buffer is shared and if so clone it
1408  *      @skb: buffer to check
1409  *      @pri: priority for memory allocation
1410  *
1411  *      If the buffer is shared the buffer is cloned and the old copy
1412  *      drops a reference. A new clone with a single reference is returned.
1413  *      If the buffer is not shared the original buffer is returned. When
1414  *      being called from interrupt status or with spinlocks held pri must
1415  *      be GFP_ATOMIC.
1416  *
1417  *      NULL is returned on a memory allocation failure.
1418  */
1419 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1420 {
1421         might_sleep_if(gfpflags_allow_blocking(pri));
1422         if (skb_shared(skb)) {
1423                 struct sk_buff *nskb = skb_clone(skb, pri);
1424 
1425                 if (likely(nskb))
1426                         consume_skb(skb);
1427                 else
1428                         kfree_skb(skb);
1429                 skb = nskb;
1430         }
1431         return skb;
1432 }
1433 
1434 /*
1435  *      Copy shared buffers into a new sk_buff. We effectively do COW on
1436  *      packets to handle cases where we have a local reader and forward
1437  *      and a couple of other messy ones. The normal one is tcpdumping
1438  *      a packet thats being forwarded.
1439  */
1440 
1441 /**
1442  *      skb_unshare - make a copy of a shared buffer
1443  *      @skb: buffer to check
1444  *      @pri: priority for memory allocation
1445  *
1446  *      If the socket buffer is a clone then this function creates a new
1447  *      copy of the data, drops a reference count on the old copy and returns
1448  *      the new copy with the reference count at 1. If the buffer is not a clone
1449  *      the original buffer is returned. When called with a spinlock held or
1450  *      from interrupt state @pri must be %GFP_ATOMIC
1451  *
1452  *      %NULL is returned on a memory allocation failure.
1453  */
1454 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1455                                           gfp_t pri)
1456 {
1457         might_sleep_if(gfpflags_allow_blocking(pri));
1458         if (skb_cloned(skb)) {
1459                 struct sk_buff *nskb = skb_copy(skb, pri);
1460 
1461                 /* Free our shared copy */
1462                 if (likely(nskb))
1463                         consume_skb(skb);
1464                 else
1465                         kfree_skb(skb);
1466                 skb = nskb;
1467         }
1468         return skb;
1469 }
1470 
1471 /**
1472  *      skb_peek - peek at the head of an &sk_buff_head
1473  *      @list_: list to peek at
1474  *
1475  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1476  *      be careful with this one. A peek leaves the buffer on the
1477  *      list and someone else may run off with it. You must hold
1478  *      the appropriate locks or have a private queue to do this.
1479  *
1480  *      Returns %NULL for an empty list or a pointer to the head element.
1481  *      The reference count is not incremented and the reference is therefore
1482  *      volatile. Use with caution.
1483  */
1484 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1485 {
1486         struct sk_buff *skb = list_->next;
1487 
1488         if (skb == (struct sk_buff *)list_)
1489                 skb = NULL;
1490         return skb;
1491 }
1492 
1493 /**
1494  *      skb_peek_next - peek skb following the given one from a queue
1495  *      @skb: skb to start from
1496  *      @list_: list to peek at
1497  *
1498  *      Returns %NULL when the end of the list is met or a pointer to the
1499  *      next element. The reference count is not incremented and the
1500  *      reference is therefore volatile. Use with caution.
1501  */
1502 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1503                 const struct sk_buff_head *list_)
1504 {
1505         struct sk_buff *next = skb->next;
1506 
1507         if (next == (struct sk_buff *)list_)
1508                 next = NULL;
1509         return next;
1510 }
1511 
1512 /**
1513  *      skb_peek_tail - peek at the tail of an &sk_buff_head
1514  *      @list_: list to peek at
1515  *
1516  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1517  *      be careful with this one. A peek leaves the buffer on the
1518  *      list and someone else may run off with it. You must hold
1519  *      the appropriate locks or have a private queue to do this.
1520  *
1521  *      Returns %NULL for an empty list or a pointer to the tail element.
1522  *      The reference count is not incremented and the reference is therefore
1523  *      volatile. Use with caution.
1524  */
1525 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1526 {
1527         struct sk_buff *skb = list_->prev;
1528 
1529         if (skb == (struct sk_buff *)list_)
1530                 skb = NULL;
1531         return skb;
1532 
1533 }
1534 
1535 /**
1536  *      skb_queue_len   - get queue length
1537  *      @list_: list to measure
1538  *
1539  *      Return the length of an &sk_buff queue.
1540  */
1541 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1542 {
1543         return list_->qlen;
1544 }
1545 
1546 /**
1547  *      __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1548  *      @list: queue to initialize
1549  *
1550  *      This initializes only the list and queue length aspects of
1551  *      an sk_buff_head object.  This allows to initialize the list
1552  *      aspects of an sk_buff_head without reinitializing things like
1553  *      the spinlock.  It can also be used for on-stack sk_buff_head
1554  *      objects where the spinlock is known to not be used.
1555  */
1556 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1557 {
1558         list->prev = list->next = (struct sk_buff *)list;
1559         list->qlen = 0;
1560 }
1561 
1562 /*
1563  * This function creates a split out lock class for each invocation;
1564  * this is needed for now since a whole lot of users of the skb-queue
1565  * infrastructure in drivers have different locking usage (in hardirq)
1566  * than the networking core (in softirq only). In the long run either the
1567  * network layer or drivers should need annotation to consolidate the
1568  * main types of usage into 3 classes.
1569  */
1570 static inline void skb_queue_head_init(struct sk_buff_head *list)
1571 {
1572         spin_lock_init(&list->lock);
1573         __skb_queue_head_init(list);
1574 }
1575 
1576 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1577                 struct lock_class_key *class)
1578 {
1579         skb_queue_head_init(list);
1580         lockdep_set_class(&list->lock, class);
1581 }
1582 
1583 /*
1584  *      Insert an sk_buff on a list.
1585  *
1586  *      The "__skb_xxxx()" functions are the non-atomic ones that
1587  *      can only be called with interrupts disabled.
1588  */
1589 void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
1590                 struct sk_buff_head *list);
1591 static inline void __skb_insert(struct sk_buff *newsk,
1592                                 struct sk_buff *prev, struct sk_buff *next,
1593                                 struct sk_buff_head *list)
1594 {
1595         newsk->next = next;
1596         newsk->prev = prev;
1597         next->prev  = prev->next = newsk;
1598         list->qlen++;
1599 }
1600 
1601 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1602                                       struct sk_buff *prev,
1603                                       struct sk_buff *next)
1604 {
1605         struct sk_buff *first = list->next;
1606         struct sk_buff *last = list->prev;
1607 
1608         first->prev = prev;
1609         prev->next = first;
1610 
1611         last->next = next;
1612         next->prev = last;
1613 }
1614 
1615 /**
1616  *      skb_queue_splice - join two skb lists, this is designed for stacks
1617  *      @list: the new list to add
1618  *      @head: the place to add it in the first list
1619  */
1620 static inline void skb_queue_splice(const struct sk_buff_head *list,
1621                                     struct sk_buff_head *head)
1622 {
1623         if (!skb_queue_empty(list)) {
1624                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1625                 head->qlen += list->qlen;
1626         }
1627 }
1628 
1629 /**
1630  *      skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1631  *      @list: the new list to add
1632  *      @head: the place to add it in the first list
1633  *
1634  *      The list at @list is reinitialised
1635  */
1636 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1637                                          struct sk_buff_head *head)
1638 {
1639         if (!skb_queue_empty(list)) {
1640                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1641                 head->qlen += list->qlen;
1642                 __skb_queue_head_init(list);
1643         }
1644 }
1645 
1646 /**
1647  *      skb_queue_splice_tail - join two skb lists, each list being a queue
1648  *      @list: the new list to add
1649  *      @head: the place to add it in the first list
1650  */
1651 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1652                                          struct sk_buff_head *head)
1653 {
1654         if (!skb_queue_empty(list)) {
1655                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1656                 head->qlen += list->qlen;
1657         }
1658 }
1659 
1660 /**
1661  *      skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1662  *      @list: the new list to add
1663  *      @head: the place to add it in the first list
1664  *
1665  *      Each of the lists is a queue.
1666  *      The list at @list is reinitialised
1667  */
1668 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1669                                               struct sk_buff_head *head)
1670 {
1671         if (!skb_queue_empty(list)) {
1672                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1673                 head->qlen += list->qlen;
1674                 __skb_queue_head_init(list);
1675         }
1676 }
1677 
1678 /**
1679  *      __skb_queue_after - queue a buffer at the list head
1680  *      @list: list to use
1681  *      @prev: place after this buffer
1682  *      @newsk: buffer to queue
1683  *
1684  *      Queue a buffer int the middle of a list. This function takes no locks
1685  *      and you must therefore hold required locks before calling it.
1686  *
1687  *      A buffer cannot be placed on two lists at the same time.
1688  */
1689 static inline void __skb_queue_after(struct sk_buff_head *list,
1690                                      struct sk_buff *prev,
1691                                      struct sk_buff *newsk)
1692 {
1693         __skb_insert(newsk, prev, prev->next, list);
1694 }
1695 
1696 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1697                 struct sk_buff_head *list);
1698 
1699 static inline void __skb_queue_before(struct sk_buff_head *list,
1700                                       struct sk_buff *next,
1701                                       struct sk_buff *newsk)
1702 {
1703         __skb_insert(newsk, next->prev, next, list);
1704 }
1705 
1706 /**
1707  *      __skb_queue_head - queue a buffer at the list head
1708  *      @list: list to use
1709  *      @newsk: buffer to queue
1710  *
1711  *      Queue a buffer at the start of a list. This function takes no locks
1712  *      and you must therefore hold required locks before calling it.
1713  *
1714  *      A buffer cannot be placed on two lists at the same time.
1715  */
1716 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1717 static inline void __skb_queue_head(struct sk_buff_head *list,
1718                                     struct sk_buff *newsk)
1719 {
1720         __skb_queue_after(list, (struct sk_buff *)list, newsk);
1721 }
1722 
1723 /**
1724  *      __skb_queue_tail - queue a buffer at the list tail
1725  *      @list: list to use
1726  *      @newsk: buffer to queue
1727  *
1728  *      Queue a buffer at the end of a list. This function takes no locks
1729  *      and you must therefore hold required locks before calling it.
1730  *
1731  *      A buffer cannot be placed on two lists at the same time.
1732  */
1733 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1734 static inline void __skb_queue_tail(struct sk_buff_head *list,
1735                                    struct sk_buff *newsk)
1736 {
1737         __skb_queue_before(list, (struct sk_buff *)list, newsk);
1738 }
1739 
1740 /*
1741  * remove sk_buff from list. _Must_ be called atomically, and with
1742  * the list known..
1743  */
1744 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1745 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1746 {
1747         struct sk_buff *next, *prev;
1748 
1749         list->qlen--;
1750         next       = skb->next;
1751         prev       = skb->prev;
1752         skb->next  = skb->prev = NULL;
1753         next->prev = prev;
1754         prev->next = next;
1755 }
1756 
1757 /**
1758  *      __skb_dequeue - remove from the head of the queue
1759  *      @list: list to dequeue from
1760  *
1761  *      Remove the head of the list. This function does not take any locks
1762  *      so must be used with appropriate locks held only. The head item is
1763  *      returned or %NULL if the list is empty.
1764  */
1765 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1766 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1767 {
1768         struct sk_buff *skb = skb_peek(list);
1769         if (skb)
1770                 __skb_unlink(skb, list);
1771         return skb;
1772 }
1773 
1774 /**
1775  *      __skb_dequeue_tail - remove from the tail of the queue
1776  *      @list: list to dequeue from
1777  *
1778  *      Remove the tail of the list. This function does not take any locks
1779  *      so must be used with appropriate locks held only. The tail item is
1780  *      returned or %NULL if the list is empty.
1781  */
1782 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1783 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1784 {
1785         struct sk_buff *skb = skb_peek_tail(list);
1786         if (skb)
1787                 __skb_unlink(skb, list);
1788         return skb;
1789 }
1790 
1791 
1792 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1793 {
1794         return skb->data_len;
1795 }
1796 
1797 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1798 {
1799         return skb->len - skb->data_len;
1800 }
1801 
1802 static inline int skb_pagelen(const struct sk_buff *skb)
1803 {
1804         int i, len = 0;
1805 
1806         for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1807                 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1808         return len + skb_headlen(skb);
1809 }
1810 
1811 /**
1812  * __skb_fill_page_desc - initialise a paged fragment in an skb
1813  * @skb: buffer containing fragment to be initialised
1814  * @i: paged fragment index to initialise
1815  * @page: the page to use for this fragment
1816  * @off: the offset to the data with @page
1817  * @size: the length of the data
1818  *
1819  * Initialises the @i'th fragment of @skb to point to &size bytes at
1820  * offset @off within @page.
1821  *
1822  * Does not take any additional reference on the fragment.
1823  */
1824 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1825                                         struct page *page, int off, int size)
1826 {
1827         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1828 
1829         /*
1830          * Propagate page pfmemalloc to the skb if we can. The problem is
1831          * that not all callers have unique ownership of the page but rely
1832          * on page_is_pfmemalloc doing the right thing(tm).
1833          */
1834         frag->page.p              = page;
1835         frag->page_offset         = off;
1836         skb_frag_size_set(frag, size);
1837 
1838         page = compound_head(page);
1839         if (page_is_pfmemalloc(page))
1840                 skb->pfmemalloc = true;
1841 }
1842 
1843 /**
1844  * skb_fill_page_desc - initialise a paged fragment in an skb
1845  * @skb: buffer containing fragment to be initialised
1846  * @i: paged fragment index to initialise
1847  * @page: the page to use for this fragment
1848  * @off: the offset to the data with @page
1849  * @size: the length of the data
1850  *
1851  * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1852  * @skb to point to @size bytes at offset @off within @page. In
1853  * addition updates @skb such that @i is the last fragment.
1854  *
1855  * Does not take any additional reference on the fragment.
1856  */
1857 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1858                                       struct page *page, int off, int size)
1859 {
1860         __skb_fill_page_desc(skb, i, page, off, size);
1861         skb_shinfo(skb)->nr_frags = i + 1;
1862 }
1863 
1864 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
1865                      int size, unsigned int truesize);
1866 
1867 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
1868                           unsigned int truesize);
1869 
1870 #define SKB_PAGE_ASSERT(skb)    BUG_ON(skb_shinfo(skb)->nr_frags)
1871 #define SKB_FRAG_ASSERT(skb)    BUG_ON(skb_has_frag_list(skb))
1872 #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
1873 
1874 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1875 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1876 {
1877         return skb->head + skb->tail;
1878 }
1879 
1880 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1881 {
1882         skb->tail = skb->data - skb->head;
1883 }
1884 
1885 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1886 {
1887         skb_reset_tail_pointer(skb);
1888         skb->tail += offset;
1889 }
1890 
1891 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1892 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1893 {
1894         return skb->tail;
1895 }
1896 
1897 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1898 {
1899         skb->tail = skb->data;
1900 }
1901 
1902 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1903 {
1904         skb->tail = skb->data + offset;
1905 }
1906 
1907 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1908 
1909 /*
1910  *      Add data to an sk_buff
1911  */
1912 unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
1913 unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1914 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1915 {
1916         unsigned char *tmp = skb_tail_pointer(skb);
1917         SKB_LINEAR_ASSERT(skb);
1918         skb->tail += len;
1919         skb->len  += len;
1920         return tmp;
1921 }
1922 
1923 unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1924 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1925 {
1926         skb->data -= len;
1927         skb->len  += len;
1928         return skb->data;
1929 }
1930 
1931 unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1932 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1933 {
1934         skb->len -= len;
1935         BUG_ON(skb->len < skb->data_len);
1936         return skb->data += len;
1937 }
1938 
1939 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1940 {
1941         return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1942 }
1943 
1944 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1945 
1946 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1947 {
1948         if (len > skb_headlen(skb) &&
1949             !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1950                 return NULL;
1951         skb->len -= len;
1952         return skb->data += len;
1953 }
1954 
1955 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1956 {
1957         return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1958 }
1959 
1960 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1961 {
1962         if (likely(len <= skb_headlen(skb)))
1963                 return 1;
1964         if (unlikely(len > skb->len))
1965                 return 0;
1966         return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1967 }
1968 
1969 /**
1970  *      skb_headroom - bytes at buffer head
1971  *      @skb: buffer to check
1972  *
1973  *      Return the number of bytes of free space at the head of an &sk_buff.
1974  */
1975 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1976 {
1977         return skb->data - skb->head;
1978 }
1979 
1980 /**
1981  *      skb_tailroom - bytes at buffer end
1982  *      @skb: buffer to check
1983  *
1984  *      Return the number of bytes of free space at the tail of an sk_buff
1985  */
1986 static inline int skb_tailroom(const struct sk_buff *skb)
1987 {
1988         return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1989 }
1990 
1991 /**
1992  *      skb_availroom - bytes at buffer end
1993  *      @skb: buffer to check
1994  *
1995  *      Return the number of bytes of free space at the tail of an sk_buff
1996  *      allocated by sk_stream_alloc()
1997  */
1998 static inline int skb_availroom(const struct sk_buff *skb)
1999 {
2000         if (skb_is_nonlinear(skb))
2001                 return 0;
2002 
2003         return skb->end - skb->tail - skb->reserved_tailroom;
2004 }
2005 
2006 /**
2007  *      skb_reserve - adjust headroom
2008  *      @skb: buffer to alter
2009  *      @len: bytes to move
2010  *
2011  *      Increase the headroom of an empty &sk_buff by reducing the tail
2012  *      room. This is only allowed for an empty buffer.
2013  */
2014 static inline void skb_reserve(struct sk_buff *skb, int len)
2015 {
2016         skb->data += len;
2017         skb->tail += len;
2018 }
2019 
2020 /**
2021  *      skb_tailroom_reserve - adjust reserved_tailroom
2022  *      @skb: buffer to alter
2023  *      @mtu: maximum amount of headlen permitted
2024  *      @needed_tailroom: minimum amount of reserved_tailroom
2025  *
2026  *      Set reserved_tailroom so that headlen can be as large as possible but
2027  *      not larger than mtu and tailroom cannot be smaller than
2028  *      needed_tailroom.
2029  *      The required headroom should already have been reserved before using
2030  *      this function.
2031  */
2032 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2033                                         unsigned int needed_tailroom)
2034 {
2035         SKB_LINEAR_ASSERT(skb);
2036         if (mtu < skb_tailroom(skb) - needed_tailroom)
2037                 /* use at most mtu */
2038                 skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2039         else
2040                 /* use up to all available space */
2041                 skb->reserved_tailroom = needed_tailroom;
2042 }
2043 
2044 #define ENCAP_TYPE_ETHER        0
2045 #define ENCAP_TYPE_IPPROTO      1
2046 
2047 static inline void skb_set_inner_protocol(struct sk_buff *skb,
2048                                           __be16 protocol)
2049 {
2050         skb->inner_protocol = protocol;
2051         skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2052 }
2053 
2054 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2055                                          __u8 ipproto)
2056 {
2057         skb->inner_ipproto = ipproto;
2058         skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2059 }
2060 
2061 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2062 {
2063         skb->inner_mac_header = skb->mac_header;
2064         skb->inner_network_header = skb->network_header;
2065         skb->inner_transport_header = skb->transport_header;
2066 }
2067 
2068 static inline void skb_reset_mac_len(struct sk_buff *skb)
2069 {
2070         skb->mac_len = skb->network_header - skb->mac_header;
2071 }
2072 
2073 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2074                                                         *skb)
2075 {
2076         return skb->head + skb->inner_transport_header;
2077 }
2078 
2079 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2080 {
2081         return skb_inner_transport_header(skb) - skb->data;
2082 }
2083 
2084 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2085 {
2086         skb->inner_transport_header = skb->data - skb->head;
2087 }
2088 
2089 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2090                                                    const int offset)
2091 {
2092         skb_reset_inner_transport_header(skb);
2093         skb->inner_transport_header += offset;
2094 }
2095 
2096 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2097 {
2098         return skb->head + skb->inner_network_header;
2099 }
2100 
2101 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2102 {
2103         skb->inner_network_header = skb->data - skb->head;
2104 }
2105 
2106 static inline void skb_set_inner_network_header(struct sk_buff *skb,
2107                                                 const int offset)
2108 {
2109         skb_reset_inner_network_header(skb);
2110         skb->inner_network_header += offset;
2111 }
2112 
2113 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2114 {
2115         return skb->head + skb->inner_mac_header;
2116 }
2117 
2118 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2119 {
2120         skb->inner_mac_header = skb->data - skb->head;
2121 }
2122 
2123 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2124                                             const int offset)
2125 {
2126         skb_reset_inner_mac_header(skb);
2127         skb->inner_mac_header += offset;
2128 }
2129 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2130 {
2131         return skb->transport_header != (typeof(skb->transport_header))~0U;
2132 }
2133 
2134 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2135 {
2136         return skb->head + skb->transport_header;
2137 }
2138 
2139 static inline void skb_reset_transport_header(struct sk_buff *skb)
2140 {
2141         skb->transport_header = skb->data - skb->head;
2142 }
2143 
2144 static inline void skb_set_transport_header(struct sk_buff *skb,
2145                                             const int offset)
2146 {
2147         skb_reset_transport_header(skb);
2148         skb->transport_header += offset;
2149 }
2150 
2151 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2152 {
2153         return skb->head + skb->network_header;
2154 }
2155 
2156 static inline void skb_reset_network_header(struct sk_buff *skb)
2157 {
2158         skb->network_header = skb->data - skb->head;
2159 }
2160 
2161 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2162 {
2163         skb_reset_network_header(skb);
2164         skb->network_header += offset;
2165 }
2166 
2167 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2168 {
2169         return skb->head + skb->mac_header;
2170 }
2171 
2172 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2173 {
2174         return skb->mac_header != (typeof(skb->mac_header))~0U;
2175 }
2176 
2177 static inline void skb_reset_mac_header(struct sk_buff *skb)
2178 {
2179         skb->mac_header = skb->data - skb->head;
2180 }
2181 
2182 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2183 {
2184         skb_reset_mac_header(skb);
2185         skb->mac_header += offset;
2186 }
2187 
2188 static inline void skb_pop_mac_header(struct sk_buff *skb)
2189 {
2190         skb->mac_header = skb->network_header;
2191 }
2192 
2193 static inline void skb_probe_transport_header(struct sk_buff *skb,
2194                                               const int offset_hint)
2195 {
2196         struct flow_keys keys;
2197 
2198         if (skb_transport_header_was_set(skb))
2199                 return;
2200         else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
2201                 skb_set_transport_header(skb, keys.control.thoff);
2202         else
2203                 skb_set_transport_header(skb, offset_hint);
2204 }
2205 
2206 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2207 {
2208         if (skb_mac_header_was_set(skb)) {
2209                 const unsigned char *old_mac = skb_mac_header(skb);
2210 
2211                 skb_set_mac_header(skb, -skb->mac_len);
2212                 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2213         }
2214 }
2215 
2216 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2217 {
2218         return skb->csum_start - skb_headroom(skb);
2219 }
2220 
2221 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
2222 {
2223         return skb->head + skb->csum_start;
2224 }
2225 
2226 static inline int skb_transport_offset(const struct sk_buff *skb)
2227 {
2228         return skb_transport_header(skb) - skb->data;
2229 }
2230 
2231 static inline u32 skb_network_header_len(const struct sk_buff *skb)
2232 {
2233         return skb->transport_header - skb->network_header;
2234 }
2235 
2236 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2237 {
2238         return skb->inner_transport_header - skb->inner_network_header;
2239 }
2240 
2241 static inline int skb_network_offset(const struct sk_buff *skb)
2242 {
2243         return skb_network_header(skb) - skb->data;
2244 }
2245 
2246 static inline int skb_inner_network_offset(const struct sk_buff *skb)
2247 {
2248         return skb_inner_network_header(skb) - skb->data;
2249 }
2250 
2251 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2252 {
2253         return pskb_may_pull(skb, skb_network_offset(skb) + len);
2254 }
2255 
2256 /*
2257  * CPUs often take a performance hit when accessing unaligned memory
2258  * locations. The actual performance hit varies, it can be small if the
2259  * hardware handles it or large if we have to take an exception and fix it
2260  * in software.
2261  *
2262  * Since an ethernet header is 14 bytes network drivers often end up with
2263  * the IP header at an unaligned offset. The IP header can be aligned by
2264  * shifting the start of the packet by 2 bytes. Drivers should do this
2265  * with:
2266  *
2267  * skb_reserve(skb, NET_IP_ALIGN);
2268  *
2269  * The downside to this alignment of the IP header is that the DMA is now
2270  * unaligned. On some architectures the cost of an unaligned DMA is high
2271  * and this cost outweighs the gains made by aligning the IP header.
2272  *
2273  * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2274  * to be overridden.
2275  */
2276 #ifndef NET_IP_ALIGN
2277 #define NET_IP_ALIGN    2
2278 #endif
2279 
2280 /*
2281  * The networking layer reserves some headroom in skb data (via
2282  * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2283  * the header has to grow. In the default case, if the header has to grow
2284  * 32 bytes or less we avoid the reallocation.
2285  *
2286  * Unfortunately this headroom changes the DMA alignment of the resulting
2287  * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2288  * on some architectures. An architecture can override this value,
2289  * perhaps setting it to a cacheline in size (since that will maintain
2290  * cacheline alignment of the DMA). It must be a power of 2.
2291  *
2292  * Various parts of the networking layer expect at least 32 bytes of
2293  * headroom, you should not reduce this.
2294  *
2295  * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2296  * to reduce average number of cache lines per packet.
2297  * get_rps_cpus() for example only access one 64 bytes aligned block :
2298  * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2299  */
2300 #ifndef NET_SKB_PAD
2301 #define NET_SKB_PAD     max(32, L1_CACHE_BYTES)
2302 #endif
2303 
2304 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2305 
2306 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
2307 {
2308         if (unlikely(skb_is_nonlinear(skb))) {
2309                 WARN_ON(1);
2310                 return;
2311         }
2312         skb->len = len;
2313         skb_set_tail_pointer(skb, len);
2314 }
2315 
2316 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2317 {
2318         __skb_set_length(skb, len);
2319 }
2320 
2321 void skb_trim(struct sk_buff *skb, unsigned int len);
2322 
2323 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2324 {
2325         if (skb->data_len)
2326                 return ___pskb_trim(skb, len);
2327         __skb_trim(skb, len);
2328         return 0;
2329 }
2330 
2331 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2332 {
2333         return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2334 }
2335 
2336 /**
2337  *      pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2338  *      @skb: buffer to alter
2339  *      @len: new length
2340  *
2341  *      This is identical to pskb_trim except that the caller knows that
2342  *      the skb is not cloned so we should never get an error due to out-
2343  *      of-memory.
2344  */
2345 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2346 {
2347         int err = pskb_trim(skb, len);
2348         BUG_ON(err);
2349 }
2350 
2351 static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
2352 {
2353         unsigned int diff = len - skb->len;
2354 
2355         if (skb_tailroom(skb) < diff) {
2356                 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
2357                                            GFP_ATOMIC);
2358                 if (ret)
2359                         return ret;
2360         }
2361         __skb_set_length(skb, len);
2362         return 0;
2363 }
2364 
2365 /**
2366  *      skb_orphan - orphan a buffer
2367  *      @skb: buffer to orphan
2368  *
2369  *      If a buffer currently has an owner then we call the owner's
2370  *      destructor function and make the @skb unowned. The buffer continues
2371  *      to exist but is no longer charged to its former owner.
2372  */
2373 static inline void skb_orphan(struct sk_buff *skb)
2374 {
2375         if (skb->destructor) {
2376                 skb->destructor(skb);
2377                 skb->destructor = NULL;
2378                 skb->sk         = NULL;
2379         } else {
2380                 BUG_ON(skb->sk);
2381         }
2382 }
2383 
2384 /**
2385  *      skb_orphan_frags - orphan the frags contained in a buffer
2386  *      @skb: buffer to orphan frags from
2387  *      @gfp_mask: allocation mask for replacement pages
2388  *
2389  *      For each frag in the SKB which needs a destructor (i.e. has an
2390  *      owner) create a copy of that frag and release the original
2391  *      page by calling the destructor.
2392  */
2393 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2394 {
2395         if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
2396                 return 0;
2397         return skb_copy_ubufs(skb, gfp_mask);
2398 }
2399 
2400 /**
2401  *      __skb_queue_purge - empty a list
2402  *      @list: list to empty
2403  *
2404  *      Delete all buffers on an &sk_buff list. Each buffer is removed from
2405  *      the list and one reference dropped. This function does not take the
2406  *      list lock and the caller must hold the relevant locks to use it.
2407  */
2408 void skb_queue_purge(struct sk_buff_head *list);
2409 static inline void __skb_queue_purge(struct sk_buff_head *list)
2410 {
2411         struct sk_buff *skb;
2412         while ((skb = __skb_dequeue(list)) != NULL)
2413                 kfree_skb(skb);
2414 }
2415 
2416 void skb_rbtree_purge(struct rb_root *root);
2417 
2418 void *netdev_alloc_frag(unsigned int fragsz);
2419 
2420 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2421                                    gfp_t gfp_mask);
2422 
2423 /**
2424  *      netdev_alloc_skb - allocate an skbuff for rx on a specific device
2425  *      @dev: network device to receive on
2426  *      @length: length to allocate
2427  *
2428  *      Allocate a new &sk_buff and assign it a usage count of one. The
2429  *      buffer has unspecified headroom built in. Users should allocate
2430  *      the headroom they think they need without accounting for the
2431  *      built in space. The built in space is used for optimisations.
2432  *
2433  *      %NULL is returned if there is no free memory. Although this function
2434  *      allocates memory it can be called from an interrupt.
2435  */
2436 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2437                                                unsigned int length)
2438 {
2439         return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2440 }
2441 
2442 /* legacy helper around __netdev_alloc_skb() */
2443 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2444                                               gfp_t gfp_mask)
2445 {
2446         return __netdev_alloc_skb(NULL, length, gfp_mask);
2447 }
2448 
2449 /* legacy helper around netdev_alloc_skb() */
2450 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2451 {
2452         return netdev_alloc_skb(NULL, length);
2453 }
2454 
2455 
2456 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2457                 unsigned int length, gfp_t gfp)
2458 {
2459         struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2460 
2461         if (NET_IP_ALIGN && skb)
2462                 skb_reserve(skb, NET_IP_ALIGN);
2463         return skb;
2464 }
2465 
2466 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2467                 unsigned int length)
2468 {
2469         return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2470 }
2471 
2472 static inline void skb_free_frag(void *addr)
2473 {
2474         __free_page_frag(addr);
2475 }
2476 
2477 void *napi_alloc_frag(unsigned int fragsz);
2478 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2479                                  unsigned int length, gfp_t gfp_mask);
2480 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2481                                              unsigned int length)
2482 {
2483         return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2484 }
2485 void napi_consume_skb(struct sk_buff *skb, int budget);
2486 
2487 void __kfree_skb_flush(void);
2488 void __kfree_skb_defer(struct sk_buff *skb);
2489 
2490 /**
2491  * __dev_alloc_pages - allocate page for network Rx
2492  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2493  * @order: size of the allocation
2494  *
2495  * Allocate a new page.
2496  *
2497  * %NULL is returned if there is no free memory.
2498 */
2499 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2500                                              unsigned int order)
2501 {
2502         /* This piece of code contains several assumptions.
2503          * 1.  This is for device Rx, therefor a cold page is preferred.
2504          * 2.  The expectation is the user wants a compound page.
2505          * 3.  If requesting a order 0 page it will not be compound
2506          *     due to the check to see if order has a value in prep_new_page
2507          * 4.  __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2508          *     code in gfp_to_alloc_flags that should be enforcing this.
2509          */
2510         gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC;
2511 
2512         return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2513 }
2514 
2515 static inline struct page *dev_alloc_pages(unsigned int order)
2516 {
2517         return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
2518 }
2519 
2520 /**
2521  * __dev_alloc_page - allocate a page for network Rx
2522  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2523  *
2524  * Allocate a new page.
2525  *
2526  * %NULL is returned if there is no free memory.
2527  */
2528 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2529 {
2530         return __dev_alloc_pages(gfp_mask, 0);
2531 }
2532 
2533 static inline struct page *dev_alloc_page(void)
2534 {
2535         return dev_alloc_pages(0);
2536 }
2537 
2538 /**
2539  *      skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2540  *      @page: The page that was allocated from skb_alloc_page
2541  *      @skb: The skb that may need pfmemalloc set
2542  */
2543 static inline void skb_propagate_pfmemalloc(struct page *page,
2544                                              struct sk_buff *skb)
2545 {
2546         if (page_is_pfmemalloc(page))
2547                 skb->pfmemalloc = true;
2548 }
2549 
2550 /**
2551  * skb_frag_page - retrieve the page referred to by a paged fragment
2552  * @frag: the paged fragment
2553  *
2554  * Returns the &struct page associated with @frag.
2555  */
2556 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2557 {
2558         return frag->page.p;
2559 }
2560 
2561 /**
2562  * __skb_frag_ref - take an addition reference on a paged fragment.
2563  * @frag: the paged fragment
2564  *
2565  * Takes an additional reference on the paged fragment @frag.
2566  */
2567 static inline void __skb_frag_ref(skb_frag_t *frag)
2568 {
2569         get_page(skb_frag_page(frag));
2570 }
2571 
2572 /**
2573  * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2574  * @skb: the buffer
2575  * @f: the fragment offset.
2576  *
2577  * Takes an additional reference on the @f'th paged fragment of @skb.
2578  */
2579 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2580 {
2581         __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2582 }
2583 
2584 /**
2585  * __skb_frag_unref - release a reference on a paged fragment.
2586  * @frag: the paged fragment
2587  *
2588  * Releases a reference on the paged fragment @frag.
2589  */
2590 static inline void __skb_frag_unref(skb_frag_t *frag)
2591 {
2592         put_page(skb_frag_page(frag));
2593 }
2594 
2595 /**
2596  * skb_frag_unref - release a reference on a paged fragment of an skb.
2597  * @skb: the buffer
2598  * @f: the fragment offset
2599  *
2600  * Releases a reference on the @f'th paged fragment of @skb.
2601  */
2602 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2603 {
2604         __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2605 }
2606 
2607 /**
2608  * skb_frag_address - gets the address of the data contained in a paged fragment
2609  * @frag: the paged fragment buffer
2610  *
2611  * Returns the address of the data within @frag. The page must already
2612  * be mapped.
2613  */
2614 static inline void *skb_frag_address(const skb_frag_t *frag)
2615 {
2616         return page_address(skb_frag_page(frag)) + frag->page_offset;
2617 }
2618 
2619 /**
2620  * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2621  * @frag: the paged fragment buffer
2622  *
2623  * Returns the address of the data within @frag. Checks that the page
2624  * is mapped and returns %NULL otherwise.
2625  */
2626 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2627 {
2628         void *ptr = page_address(skb_frag_page(frag));
2629         if (unlikely(!ptr))
2630                 return NULL;
2631 
2632         return ptr + frag->page_offset;
2633 }
2634 
2635 /**
2636  * __skb_frag_set_page - sets the page contained in a paged fragment
2637  * @frag: the paged fragment
2638  * @page: the page to set
2639  *
2640  * Sets the fragment @frag to contain @page.
2641  */
2642 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2643 {
2644         frag->page.p = page;
2645 }
2646 
2647 /**
2648  * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2649  * @skb: the buffer
2650  * @f: the fragment offset
2651  * @page: the page to set
2652  *
2653  * Sets the @f'th fragment of @skb to contain @page.
2654  */
2655 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2656                                      struct page *page)
2657 {
2658         __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2659 }
2660 
2661 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2662 
2663 /**
2664  * skb_frag_dma_map - maps a paged fragment via the DMA API
2665  * @dev: the device to map the fragment to
2666  * @frag: the paged fragment to map
2667  * @offset: the offset within the fragment (starting at the
2668  *          fragment's own offset)
2669  * @size: the number of bytes to map
2670  * @dir: the direction of the mapping (%PCI_DMA_*)
2671  *
2672  * Maps the page associated with @frag to @device.
2673  */
2674 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2675                                           const skb_frag_t *frag,
2676                                           size_t offset, size_t size,
2677                                           enum dma_data_direction dir)
2678 {
2679         return dma_map_page(dev, skb_frag_page(frag),
2680                             frag->page_offset + offset, size, dir);
2681 }
2682 
2683 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2684                                         gfp_t gfp_mask)
2685 {
2686         return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2687 }
2688 
2689 
2690 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
2691                                                   gfp_t gfp_mask)
2692 {
2693         return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
2694 }
2695 
2696 
2697 /**
2698  *      skb_clone_writable - is the header of a clone writable
2699  *      @skb: buffer to check
2700  *      @len: length up to which to write
2701  *
2702  *      Returns true if modifying the header part of the cloned buffer
2703  *      does not requires the data to be copied.
2704  */
2705 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2706 {
2707         return !skb_header_cloned(skb) &&
2708                skb_headroom(skb) + len <= skb->hdr_len;
2709 }
2710 
2711 static inline int skb_try_make_writable(struct sk_buff *skb,
2712                                         unsigned int write_len)
2713 {
2714         return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
2715                pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2716 }
2717 
2718 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2719                             int cloned)
2720 {
2721         int delta = 0;
2722 
2723         if (headroom > skb_headroom(skb))
2724                 delta = headroom - skb_headroom(skb);
2725 
2726         if (delta || cloned)
2727                 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2728                                         GFP_ATOMIC);
2729         return 0;
2730 }
2731 
2732 /**
2733  *      skb_cow - copy header of skb when it is required
2734  *      @skb: buffer to cow
2735  *      @headroom: needed headroom
2736  *
2737  *      If the skb passed lacks sufficient headroom or its data part
2738  *      is shared, data is reallocated. If reallocation fails, an error
2739  *      is returned and original skb is not changed.
2740  *
2741  *      The result is skb with writable area skb->head...skb->tail
2742  *      and at least @headroom of space at head.
2743  */
2744 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2745 {
2746         return __skb_cow(skb, headroom, skb_cloned(skb));
2747 }
2748 
2749 /**
2750  *      skb_cow_head - skb_cow but only making the head writable
2751  *      @skb: buffer to cow
2752  *      @headroom: needed headroom
2753  *
2754  *      This function is identical to skb_cow except that we replace the
2755  *      skb_cloned check by skb_header_cloned.  It should be used when
2756  *      you only need to push on some header and do not need to modify
2757  *      the data.
2758  */
2759 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2760 {
2761         return __skb_cow(skb, headroom, skb_header_cloned(skb));
2762 }
2763 
2764 /**
2765  *      skb_padto       - pad an skbuff up to a minimal size
2766  *      @skb: buffer to pad
2767  *      @len: minimal length
2768  *
2769  *      Pads up a buffer to ensure the trailing bytes exist and are
2770  *      blanked. If the buffer already contains sufficient data it
2771  *      is untouched. Otherwise it is extended. Returns zero on
2772  *      success. The skb is freed on error.
2773  */
2774 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2775 {
2776         unsigned int size = skb->len;
2777         if (likely(size >= len))
2778                 return 0;
2779         return skb_pad(skb, len - size);
2780 }
2781 
2782 /**
2783  *      skb_put_padto - increase size and pad an skbuff up to a minimal size
2784  *      @skb: buffer to pad
2785  *      @len: minimal length
2786  *
2787  *      Pads up a buffer to ensure the trailing bytes exist and are
2788  *      blanked. If the buffer already contains sufficient data it
2789  *      is untouched. Otherwise it is extended. Returns zero on
2790  *      success. The skb is freed on error.
2791  */
2792 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
2793 {
2794         unsigned int size = skb->len;
2795 
2796         if (unlikely(size < len)) {
2797                 len -= size;
2798                 if (skb_pad(skb, len))
2799                         return -ENOMEM;
2800                 __skb_put(skb, len);
2801         }
2802         return 0;
2803 }
2804 
2805 static inline int skb_add_data(struct sk_buff *skb,
2806                                struct iov_iter *from, int copy)
2807 {
2808         const int off = skb->len;
2809 
2810         if (skb->ip_summed == CHECKSUM_NONE) {
2811                 __wsum csum = 0;
2812                 if (csum_and_copy_from_iter(skb_put(skb, copy), copy,
2813                                             &csum, from) == copy) {
2814                         skb->csum = csum_block_add(skb->csum, csum, off);
2815                         return 0;
2816                 }
2817         } else if (copy_from_iter(skb_put(skb, copy), copy, from) == copy)
2818                 return 0;
2819 
2820         __skb_trim(skb, off);
2821         return -EFAULT;
2822 }
2823 
2824 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2825                                     const struct page *page, int off)
2826 {
2827         if (i) {
2828                 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2829 
2830                 return page == skb_frag_page(frag) &&
2831                        off == frag->page_offset + skb_frag_size(frag);
2832         }
2833         return false;
2834 }
2835 
2836 static inline int __skb_linearize(struct sk_buff *skb)
2837 {
2838         return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2839 }
2840 
2841 /**
2842  *      skb_linearize - convert paged skb to linear one
2843  *      @skb: buffer to linarize
2844  *
2845  *      If there is no free memory -ENOMEM is returned, otherwise zero
2846  *      is returned and the old skb data released.
2847  */
2848 static inline int skb_linearize(struct sk_buff *skb)
2849 {
2850         return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2851 }
2852 
2853 /**
2854  * skb_has_shared_frag - can any frag be overwritten
2855  * @skb: buffer to test
2856  *
2857  * Return true if the skb has at least one frag that might be modified
2858  * by an external entity (as in vmsplice()/sendfile())
2859  */
2860 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2861 {
2862         return skb_is_nonlinear(skb) &&
2863                skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2864 }
2865 
2866 /**
2867  *      skb_linearize_cow - make sure skb is linear and writable
2868  *      @skb: buffer to process
2869  *
2870  *      If there is no free memory -ENOMEM is returned, otherwise zero
2871  *      is returned and the old skb data released.
2872  */
2873 static inline int skb_linearize_cow(struct sk_buff *skb)
2874 {
2875         return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2876                __skb_linearize(skb) : 0;
2877 }
2878 
2879 static __always_inline void
2880 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
2881                      unsigned int off)
2882 {
2883         if (skb->ip_summed == CHECKSUM_COMPLETE)
2884                 skb->csum = csum_block_sub(skb->csum,
2885                                            csum_partial(start, len, 0), off);
2886         else if (skb->ip_summed == CHECKSUM_PARTIAL &&
2887                  skb_checksum_start_offset(skb) < 0)
2888                 skb->ip_summed = CHECKSUM_NONE;
2889 }
2890 
2891 /**
2892  *      skb_postpull_rcsum - update checksum for received skb after pull
2893  *      @skb: buffer to update
2894  *      @start: start of data before pull
2895  *      @len: length of data pulled
2896  *
2897  *      After doing a pull on a received packet, you need to call this to
2898  *      update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2899  *      CHECKSUM_NONE so that it can be recomputed from scratch.
2900  */
2901 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2902                                       const void *start, unsigned int len)
2903 {
2904         __skb_postpull_rcsum(skb, start, len, 0);
2905 }
2906 
2907 static __always_inline void
2908 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
2909                      unsigned int off)
2910 {
2911         if (skb->ip_summed == CHECKSUM_COMPLETE)
2912                 skb->csum = csum_block_add(skb->csum,
2913                                            csum_partial(start, len, 0), off);
2914 }
2915 
2916 /**
2917  *      skb_postpush_rcsum - update checksum for received skb after push
2918  *      @skb: buffer to update
2919  *      @start: start of data after push
2920  *      @len: length of data pushed
2921  *
2922  *      After doing a push on a received packet, you need to call this to
2923  *      update the CHECKSUM_COMPLETE checksum.
2924  */
2925 static inline void skb_postpush_rcsum(struct sk_buff *skb,
2926                                       const void *start, unsigned int len)
2927 {
2928         __skb_postpush_rcsum(skb, start, len, 0);
2929 }
2930 
2931 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2932 
2933 /**
2934  *      skb_push_rcsum - push skb and update receive checksum
2935  *      @skb: buffer to update
2936  *      @len: length of data pulled
2937  *
2938  *      This function performs an skb_push on the packet and updates
2939  *      the CHECKSUM_COMPLETE checksum.  It should be used on
2940  *      receive path processing instead of skb_push unless you know
2941  *      that the checksum difference is zero (e.g., a valid IP header)
2942  *      or you are setting ip_summed to CHECKSUM_NONE.
2943  */
2944 static inline unsigned char *skb_push_rcsum(struct sk_buff *skb,
2945                                             unsigned int len)
2946 {
2947         skb_push(skb, len);
2948         skb_postpush_rcsum(skb, skb->data, len);
2949         return skb->data;
2950 }
2951 
2952 /**
2953  *      pskb_trim_rcsum - trim received skb and update checksum
2954  *      @skb: buffer to trim
2955  *      @len: new length
2956  *
2957  *      This is exactly the same as pskb_trim except that it ensures the
2958  *      checksum of received packets are still valid after the operation.
2959  */
2960 
2961 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2962 {
2963         if (likely(len >= skb->len))
2964                 return 0;
2965         if (skb->ip_summed == CHECKSUM_COMPLETE)
2966                 skb->ip_summed = CHECKSUM_NONE;
2967         return __pskb_trim(skb, len);
2968 }
2969 
2970 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2971 {
2972         if (skb->ip_summed == CHECKSUM_COMPLETE)
2973                 skb->ip_summed = CHECKSUM_NONE;
2974         __skb_trim(skb, len);
2975         return 0;
2976 }
2977 
2978 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
2979 {
2980         if (skb->ip_summed == CHECKSUM_COMPLETE)
2981                 skb->ip_summed = CHECKSUM_NONE;
2982         return __skb_grow(skb, len);
2983 }
2984 
2985 #define skb_queue_walk(queue, skb) \
2986                 for (skb = (queue)->next;                                       \
2987                      skb != (struct sk_buff *)(queue);                          \
2988                      skb = skb->next)
2989 
2990 #define skb_queue_walk_safe(queue, skb, tmp)                                    \
2991                 for (skb = (queue)->next, tmp = skb->next;                      \
2992                      skb != (struct sk_buff *)(queue);                          \
2993                      skb = tmp, tmp = skb->next)
2994 
2995 #define skb_queue_walk_from(queue, skb)                                         \
2996                 for (; skb != (struct sk_buff *)(queue);                        \
2997                      skb = skb->next)
2998 
2999 #define skb_queue_walk_from_safe(queue, skb, tmp)                               \
3000                 for (tmp = skb->next;                                           \
3001                      skb != (struct sk_buff *)(queue);                          \
3002                      skb = tmp, tmp = skb->next)
3003 
3004 #define skb_queue_reverse_walk(queue, skb) \
3005                 for (skb = (queue)->prev;                                       \
3006                      skb != (struct sk_buff *)(queue);                          \
3007                      skb = skb->prev)
3008 
3009 #define skb_queue_reverse_walk_safe(queue, skb, tmp)                            \
3010                 for (skb = (queue)->prev, tmp = skb->prev;                      \
3011                      skb != (struct sk_buff *)(queue);                          \
3012                      skb = tmp, tmp = skb->prev)
3013 
3014 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp)                       \
3015                 for (tmp = skb->prev;                                           \
3016                      skb != (struct sk_buff *)(queue);                          \
3017                      skb = tmp, tmp = skb->prev)
3018 
3019 static inline bool skb_has_frag_list(const struct sk_buff *skb)
3020 {
3021         return skb_shinfo(skb)->frag_list != NULL;
3022 }
3023 
3024 static inline void skb_frag_list_init(struct sk_buff *skb)
3025 {
3026         skb_shinfo(skb)->frag_list = NULL;
3027 }
3028 
3029 #define skb_walk_frags(skb, iter)       \
3030         for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3031 
3032 
3033 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
3034                                 const struct sk_buff *skb);
3035 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
3036                                         int *peeked, int *off, int *err,
3037                                         struct sk_buff **last);
3038 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
3039                                     int *peeked, int *off, int *err);
3040 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
3041                                   int *err);
3042 unsigned int datagram_poll(struct file *file, struct socket *sock,
3043                            struct poll_table_struct *wait);
3044 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
3045                            struct iov_iter *to, int size);
3046 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
3047                                         struct msghdr *msg, int size)
3048 {
3049         return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
3050 }
3051 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
3052                                    struct msghdr *msg);
3053 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
3054                                  struct iov_iter *from, int len);
3055 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
3056 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
3057 void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
3058 static inline void skb_free_datagram_locked(struct sock *sk,
3059                                             struct sk_buff *skb)
3060 {
3061         __skb_free_datagram_locked(sk, skb, 0);
3062 }
3063 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
3064 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
3065 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
3066 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
3067                               int len, __wsum csum);
3068 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3069                     struct pipe_inode_info *pipe, unsigned int len,
3070                     unsigned int flags);
3071 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
3072 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
3073 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
3074                  int len, int hlen);
3075 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
3076 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
3077 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
3078 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
3079 bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu);
3080 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
3081 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
3082 int skb_ensure_writable(struct sk_buff *skb, int write_len);
3083 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
3084 int skb_vlan_pop(struct sk_buff *skb);
3085 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
3086 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
3087                              gfp_t gfp);
3088 
3089 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
3090 {
3091         return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3092 }
3093 
3094 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
3095 {
3096         return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3097 }
3098 
3099 struct skb_checksum_ops {
3100         __wsum (*update)(const void *mem, int len, __wsum wsum);
3101         __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
3102 };
3103 
3104 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3105                       __wsum csum, const struct skb_checksum_ops *ops);
3106 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
3107                     __wsum csum);
3108 
3109 static inline void * __must_check
3110 __skb_header_pointer(const struct sk_buff *skb, int offset,
3111                      int len, void *data, int hlen, void *buffer)
3112 {
3113         if (hlen - offset >= len)
3114                 return data + offset;
3115 
3116         if (!skb ||
3117             skb_copy_bits(skb, offset, buffer, len) < 0)
3118                 return NULL;
3119 
3120         return buffer;
3121 }
3122 
3123 static inline void * __must_check
3124 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
3125 {
3126         return __skb_header_pointer(skb, offset, len, skb->data,
3127                                     skb_headlen(skb), buffer);
3128 }
3129 
3130 /**
3131  *      skb_needs_linearize - check if we need to linearize a given skb
3132  *                            depending on the given device features.
3133  *      @skb: socket buffer to check
3134  *      @features: net device features
3135  *
3136  *      Returns true if either:
3137  *      1. skb has frag_list and the device doesn't support FRAGLIST, or
3138  *      2. skb is fragmented and the device does not support SG.
3139  */
3140 static inline bool skb_needs_linearize(struct sk_buff *skb,
3141                                        netdev_features_t features)
3142 {
3143         return skb_is_nonlinear(skb) &&
3144                ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3145                 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3146 }
3147 
3148 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3149                                              void *to,
3150                                              const unsigned int len)
3151 {
3152         memcpy(to, skb->data, len);
3153 }
3154 
3155 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3156                                                     const int offset, void *to,
3157                                                     const unsigned int len)
3158 {
3159         memcpy(to, skb->data + offset, len);
3160 }
3161 
3162 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3163                                            const void *from,
3164                                            const unsigned int len)
3165 {
3166         memcpy(skb->data, from, len);
3167 }
3168 
3169 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3170                                                   const int offset,
3171                                                   const void *from,
3172                                                   const unsigned int len)
3173 {
3174         memcpy(skb->data + offset, from, len);
3175 }
3176 
3177 void skb_init(void);
3178 
3179 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3180 {
3181         return skb->tstamp;
3182 }
3183 
3184 /**
3185  *      skb_get_timestamp - get timestamp from a skb
3186  *      @skb: skb to get stamp from
3187  *      @stamp: pointer to struct timeval to store stamp in
3188  *
3189  *      Timestamps are stored in the skb as offsets to a base timestamp.
3190  *      This function converts the offset back to a struct timeval and stores
3191  *      it in stamp.
3192  */
3193 static inline void skb_get_timestamp(const struct sk_buff *skb,
3194                                      struct timeval *stamp)
3195 {
3196         *stamp = ktime_to_timeval(skb->tstamp);
3197 }
3198 
3199 static inline void skb_get_timestampns(const struct sk_buff *skb,
3200                                        struct timespec *stamp)
3201 {
3202         *stamp = ktime_to_timespec(skb->tstamp);
3203 }
3204 
3205 static inline void __net_timestamp(struct sk_buff *skb)
3206 {
3207         skb->tstamp = ktime_get_real();
3208 }
3209 
3210 static inline ktime_t net_timedelta(ktime_t t)
3211 {
3212         return ktime_sub(ktime_get_real(), t);
3213 }
3214 
3215 static inline ktime_t net_invalid_timestamp(void)
3216 {
3217         return ktime_set(0, 0);
3218 }
3219 
3220 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3221 
3222 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3223 
3224 void skb_clone_tx_timestamp(struct sk_buff *skb);
3225 bool skb_defer_rx_timestamp(struct sk_buff *skb);
3226 
3227 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3228 
3229 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3230 {
3231 }
3232 
3233 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3234 {
3235         return false;
3236 }
3237 
3238 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3239 
3240 /**
3241  * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3242  *
3243  * PHY drivers may accept clones of transmitted packets for
3244  * timestamping via their phy_driver.txtstamp method. These drivers
3245  * must call this function to return the skb back to the stack with a
3246  * timestamp.
3247  *
3248  * @skb: clone of the the original outgoing packet
3249  * @hwtstamps: hardware time stamps
3250  *
3251  */
3252 void skb_complete_tx_timestamp(struct sk_buff *skb,
3253                                struct skb_shared_hwtstamps *hwtstamps);
3254 
3255 void __skb_tstamp_tx(struct sk_buff *orig_skb,
3256                      struct skb_shared_hwtstamps *hwtstamps,
3257                      struct sock *sk, int tstype);
3258 
3259 /**
3260  * skb_tstamp_tx - queue clone of skb with send time stamps
3261  * @orig_skb:   the original outgoing packet
3262  * @hwtstamps:  hardware time stamps, may be NULL if not available
3263  *
3264  * If the skb has a socket associated, then this function clones the
3265  * skb (thus sharing the actual data and optional structures), stores
3266  * the optional hardware time stamping information (if non NULL) or
3267  * generates a software time stamp (otherwise), then queues the clone
3268  * to the error queue of the socket.  Errors are silently ignored.
3269  */
3270 void skb_tstamp_tx(struct sk_buff *orig_skb,
3271                    struct skb_shared_hwtstamps *hwtstamps);
3272 
3273 static inline void sw_tx_timestamp(struct sk_buff *skb)
3274 {
3275         if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
3276             !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
3277                 skb_tstamp_tx(skb, NULL);
3278 }
3279 
3280 /**
3281  * skb_tx_timestamp() - Driver hook for transmit timestamping
3282  *
3283  * Ethernet MAC Drivers should call this function in their hard_xmit()
3284  * function immediately before giving the sk_buff to the MAC hardware.
3285  *
3286  * Specifically, one should make absolutely sure that this function is
3287  * called before TX completion of this packet can trigger.  Otherwise
3288  * the packet could potentially already be freed.
3289  *
3290  * @skb: A socket buffer.
3291  */
3292 static inline void skb_tx_timestamp(struct sk_buff *skb)
3293 {
3294         skb_clone_tx_timestamp(skb);
3295         sw_tx_timestamp(skb);
3296 }
3297 
3298 /**
3299  * skb_complete_wifi_ack - deliver skb with wifi status
3300  *
3301  * @skb: the original outgoing packet
3302  * @acked: ack status
3303  *
3304  */
3305 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3306 
3307 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3308 __sum16 __skb_checksum_complete(struct sk_buff *skb);
3309 
3310 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3311 {
3312         return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3313                 skb->csum_valid ||
3314                 (skb->ip_summed == CHECKSUM_PARTIAL &&
3315                  skb_checksum_start_offset(skb) >= 0));
3316 }
3317 
3318 /**
3319  *      skb_checksum_complete - Calculate checksum of an entire packet
3320  *      @skb: packet to process
3321  *
3322  *      This function calculates the checksum over the entire packet plus
3323  *      the value of skb->csum.  The latter can be used to supply the
3324  *      checksum of a pseudo header as used by TCP/UDP.  It returns the
3325  *      checksum.
3326  *
3327  *      For protocols that contain complete checksums such as ICMP/TCP/UDP,
3328  *      this function can be used to verify that checksum on received
3329  *      packets.  In that case the function should return zero if the
3330  *      checksum is correct.  In particular, this function will return zero
3331  *      if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3332  *      hardware has already verified the correctness of the checksum.
3333  */
3334 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3335 {
3336         return skb_csum_unnecessary(skb) ?
3337                0 : __skb_checksum_complete(skb);
3338 }
3339 
3340 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3341 {
3342         if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3343                 if (skb->csum_level == 0)
3344                         skb->ip_summed = CHECKSUM_NONE;
3345                 else
3346                         skb->csum_level--;
3347         }
3348 }
3349 
3350 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3351 {
3352         if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3353                 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3354                         skb->csum_level++;
3355         } else if (skb->ip_summed == CHECKSUM_NONE) {
3356                 skb->ip_summed = CHECKSUM_UNNECESSARY;
3357                 skb->csum_level = 0;
3358         }
3359 }
3360 
3361 static inline void __skb_mark_checksum_bad(struct sk_buff *skb)
3362 {
3363         /* Mark current checksum as bad (typically called from GRO
3364          * path). In the case that ip_summed is CHECKSUM_NONE
3365          * this must be the first checksum encountered in the packet.
3366          * When ip_summed is CHECKSUM_UNNECESSARY, this is the first
3367          * checksum after the last one validated. For UDP, a zero
3368          * checksum can not be marked as bad.
3369          */
3370 
3371         if (skb->ip_summed == CHECKSUM_NONE ||
3372             skb->ip_summed == CHECKSUM_UNNECESSARY)
3373                 skb->csum_bad = 1;
3374 }
3375 
3376 /* Check if we need to perform checksum complete validation.
3377  *
3378  * Returns true if checksum complete is needed, false otherwise
3379  * (either checksum is unnecessary or zero checksum is allowed).
3380  */
3381 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3382                                                   bool zero_okay,
3383                                                   __sum16 check)
3384 {
3385         if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3386                 skb->csum_valid = 1;
3387                 __skb_decr_checksum_unnecessary(skb);
3388                 return false;
3389         }
3390 
3391         return true;
3392 }
3393 
3394 /* For small packets <= CHECKSUM_BREAK peform checksum complete directly
3395  * in checksum_init.
3396  */
3397 #define CHECKSUM_BREAK 76
3398 
3399 /* Unset checksum-complete
3400  *
3401  * Unset checksum complete can be done when packet is being modified
3402  * (uncompressed for instance) and checksum-complete value is
3403  * invalidated.
3404  */
3405 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3406 {
3407         if (skb->ip_summed == CHECKSUM_COMPLETE)
3408                 skb->ip_summed = CHECKSUM_NONE;
3409 }
3410 
3411 /* Validate (init) checksum based on checksum complete.
3412  *
3413  * Return values:
3414  *   0: checksum is validated or try to in skb_checksum_complete. In the latter
3415  *      case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3416  *      checksum is stored in skb->csum for use in __skb_checksum_complete
3417  *   non-zero: value of invalid checksum
3418  *
3419  */
3420 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3421                                                        bool complete,
3422                                                        __wsum psum)
3423 {
3424         if (skb->ip_summed == CHECKSUM_COMPLETE) {
3425                 if (!csum_fold(csum_add(psum, skb->csum))) {
3426                         skb->csum_valid = 1;
3427                         return 0;
3428                 }
3429         } else if (skb->csum_bad) {
3430                 /* ip_summed == CHECKSUM_NONE in this case */
3431                 return (__force __sum16)1;
3432         }
3433 
3434         skb->csum = psum;
3435 
3436         if (complete || skb->len <= CHECKSUM_BREAK) {
3437                 __sum16 csum;
3438 
3439                 csum = __skb_checksum_complete(skb);
3440                 skb->csum_valid = !csum;
3441                 return csum;
3442         }
3443 
3444         return 0;
3445 }
3446 
3447 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3448 {
3449         return 0;
3450 }
3451 
3452 /* Perform checksum validate (init). Note that this is a macro since we only
3453  * want to calculate the pseudo header which is an input function if necessary.
3454  * First we try to validate without any computation (checksum unnecessary) and
3455  * then calculate based on checksum complete calling the function to compute
3456  * pseudo header.
3457  *
3458  * Return values:
3459  *   0: checksum is validated or try to in skb_checksum_complete
3460  *   non-zero: value of invalid checksum
3461  */
3462 #define __skb_checksum_validate(skb, proto, complete,                   \
3463                                 zero_okay, check, compute_pseudo)       \
3464 ({                                                                      \
3465         __sum16 __ret = 0;                                              \
3466         skb->csum_valid = 0;                                            \
3467         if (__skb_checksum_validate_needed(skb, zero_okay, check))      \
3468                 __ret = __skb_checksum_validate_complete(skb,           \
3469                                 complete, compute_pseudo(skb, proto));  \
3470         __ret;                                                          \
3471 })
3472 
3473 #define skb_checksum_init(skb, proto, compute_pseudo)                   \
3474         __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3475 
3476 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3477         __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3478 
3479 #define skb_checksum_validate(skb, proto, compute_pseudo)               \
3480         __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3481 
3482 #define skb_checksum_validate_zero_check(skb, proto, check,             \
3483                                          compute_pseudo)                \
3484         __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3485 
3486 #define skb_checksum_simple_validate(skb)                               \
3487         __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3488 
3489 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3490 {
3491         return (skb->ip_summed == CHECKSUM_NONE &&
3492                 skb->csum_valid && !skb->csum_bad);
3493 }
3494 
3495 static inline void __skb_checksum_convert(struct sk_buff *skb,
3496                                           __sum16 check, __wsum pseudo)
3497 {
3498         skb->csum = ~pseudo;
3499         skb->ip_summed = CHECKSUM_COMPLETE;
3500 }
3501 
3502 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo)     \
3503 do {                                                                    \
3504         if (__skb_checksum_convert_check(skb))                          \
3505                 __skb_checksum_convert(skb, check,                      \
3506                                        compute_pseudo(skb, proto));     \
3507 } while (0)
3508 
3509 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3510                                               u16 start, u16 offset)
3511 {
3512         skb->ip_summed = CHECKSUM_PARTIAL;
3513         skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3514         skb->csum_offset = offset - start;
3515 }
3516 
3517 /* Update skbuf and packet to reflect the remote checksum offload operation.
3518  * When called, ptr indicates the starting point for skb->csum when
3519  * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3520  * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3521  */
3522 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3523                                        int start, int offset, bool nopartial)
3524 {
3525         __wsum delta;
3526 
3527         if (!nopartial) {
3528                 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3529                 return;
3530         }
3531 
3532          if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3533                 __skb_checksum_complete(skb);
3534                 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3535         }
3536 
3537         delta = remcsum_adjust(ptr, skb->csum, start, offset);
3538 
3539         /* Adjust skb->csum since we changed the packet */
3540         skb->csum = csum_add(skb->csum, delta);
3541 }
3542 
3543 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3544 void nf_conntrack_destroy(struct nf_conntrack *nfct);
3545 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3546 {
3547         if (nfct && atomic_dec_and_test(&nfct->use))
3548                 nf_conntrack_destroy(nfct);
3549 }
3550 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3551 {
3552         if (nfct)
3553                 atomic_inc(&nfct->use);
3554 }
3555 #endif
3556 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3557 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
3558 {
3559         if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
3560                 kfree(nf_bridge);
3561 }
3562 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
3563 {
3564         if (nf_bridge)
3565                 atomic_inc(&nf_bridge->use);
3566 }
3567 #endif /* CONFIG_BRIDGE_NETFILTER */
3568 static inline void nf_reset(struct sk_buff *skb)
3569 {
3570 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3571         nf_conntrack_put(skb->nfct);
3572         skb->nfct = NULL;
3573 #endif
3574 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3575         nf_bridge_put(skb->nf_bridge);
3576         skb->nf_bridge = NULL;
3577 #endif
3578 }
3579 
3580 static inline void nf_reset_trace(struct sk_buff *skb)
3581 {
3582 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3583         skb->nf_trace = 0;
3584 #endif
3585 }
3586 
3587 /* Note: This doesn't put any conntrack and bridge info in dst. */
3588 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
3589                              bool copy)
3590 {
3591 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3592         dst->nfct = src->nfct;
3593         nf_conntrack_get(src->nfct);
3594         if (copy)
3595                 dst->nfctinfo = src->nfctinfo;
3596 #endif
3597 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3598         dst->nf_bridge  = src->nf_bridge;
3599         nf_bridge_get(src->nf_bridge);
3600 #endif
3601 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3602         if (copy)
3603                 dst->nf_trace = src->nf_trace;
3604 #endif
3605 }
3606 
3607 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
3608 {
3609 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3610         nf_conntrack_put(dst->nfct);
3611 #endif
3612 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3613         nf_bridge_put(dst->nf_bridge);
3614 #endif
3615         __nf_copy(dst, src, true);
3616 }
3617 
3618 #ifdef CONFIG_NETWORK_SECMARK
3619 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3620 {
3621         to->secmark = from->secmark;
3622 }
3623 
3624 static inline void skb_init_secmark(struct sk_buff *skb)
3625 {
3626         skb->secmark = 0;
3627 }
3628 #else
3629 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3630 { }
3631 
3632 static inline void skb_init_secmark(struct sk_buff *skb)
3633 { }
3634 #endif
3635 
3636 static inline bool skb_irq_freeable(const struct sk_buff *skb)
3637 {
3638         return !skb->destructor &&
3639 #if IS_ENABLED(CONFIG_XFRM)
3640                 !skb->sp &&
3641 #endif
3642 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3643                 !skb->nfct &&
3644 #endif
3645                 !skb->_skb_refdst &&
3646                 !skb_has_frag_list(skb);
3647 }
3648 
3649 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
3650 {
3651         skb->queue_mapping = queue_mapping;
3652 }
3653 
3654 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
3655 {
3656         return skb->queue_mapping;
3657 }
3658 
3659 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
3660 {
3661         to->queue_mapping = from->queue_mapping;
3662 }
3663 
3664 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
3665 {
3666         skb->queue_mapping = rx_queue + 1;
3667 }
3668 
3669 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
3670 {
3671         return skb->queue_mapping - 1;
3672 }
3673 
3674 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
3675 {
3676         return skb->queue_mapping != 0;
3677 }
3678 
3679 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
3680 {
3681 #ifdef CONFIG_XFRM
3682         return skb->sp;
3683 #else
3684         return NULL;
3685 #endif
3686 }
3687 
3688 /* Keeps track of mac header offset relative to skb->head.
3689  * It is useful for TSO of Tunneling protocol. e.g. GRE.
3690  * For non-tunnel skb it points to skb_mac_header() and for
3691  * tunnel skb it points to outer mac header.
3692  * Keeps track of level of encapsulation of network headers.
3693  */
3694 struct skb_gso_cb {
3695         union {
3696                 int     mac_offset;
3697                 int     data_offset;
3698         };
3699         int     encap_level;
3700         __wsum  csum;
3701         __u16   csum_start;
3702 };
3703 #define SKB_SGO_CB_OFFSET       32
3704 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
3705 
3706 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
3707 {
3708         return (skb_mac_header(inner_skb) - inner_skb->head) -
3709                 SKB_GSO_CB(inner_skb)->mac_offset;
3710 }
3711 
3712 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
3713 {
3714         int new_headroom, headroom;
3715         int ret;
3716 
3717         headroom = skb_headroom(skb);
3718         ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
3719         if (ret)
3720                 return ret;
3721 
3722         new_headroom = skb_headroom(skb);
3723         SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
3724         return 0;
3725 }
3726 
3727 static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
3728 {
3729         /* Do not update partial checksums if remote checksum is enabled. */
3730         if (skb->remcsum_offload)
3731                 return;
3732 
3733         SKB_GSO_CB(skb)->csum = res;
3734         SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
3735 }
3736 
3737 /* Compute the checksum for a gso segment. First compute the checksum value
3738  * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
3739  * then add in skb->csum (checksum from csum_start to end of packet).
3740  * skb->csum and csum_start are then updated to reflect the checksum of the
3741  * resultant packet starting from the transport header-- the resultant checksum
3742  * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
3743  * header.
3744  */
3745 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
3746 {
3747         unsigned char *csum_start = skb_transport_header(skb);
3748         int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
3749         __wsum partial = SKB_GSO_CB(skb)->csum;
3750 
3751         SKB_GSO_CB(skb)->csum = res;
3752         SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
3753 
3754         return csum_fold(csum_partial(csum_start, plen, partial));
3755 }
3756 
3757 static inline bool skb_is_gso(const struct sk_buff *skb)
3758 {
3759         return skb_shinfo(skb)->gso_size;
3760 }
3761 
3762 /* Note: Should be called only if skb_is_gso(skb) is true */
3763 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
3764 {
3765         return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
3766 }
3767 
3768 static inline void skb_gso_reset(struct sk_buff *skb)
3769 {
3770         skb_shinfo(skb)->gso_size = 0;
3771         skb_shinfo(skb)->gso_segs = 0;
3772         skb_shinfo(skb)->gso_type = 0;
3773 }
3774 
3775 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
3776 
3777 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
3778 {
3779         /* LRO sets gso_size but not gso_type, whereas if GSO is really
3780          * wanted then gso_type will be set. */
3781         const struct skb_shared_info *shinfo = skb_shinfo(skb);
3782 
3783         if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
3784             unlikely(shinfo->gso_type == 0)) {
3785                 __skb_warn_lro_forwarding(skb);
3786                 return true;
3787         }
3788         return false;
3789 }
3790 
3791 static inline void skb_forward_csum(struct sk_buff *skb)
3792 {
3793         /* Unfortunately we don't support this one.  Any brave souls? */
3794         if (skb->ip_summed == CHECKSUM_COMPLETE)
3795                 skb->ip_summed = CHECKSUM_NONE;
3796 }
3797 
3798 /**
3799  * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
3800  * @skb: skb to check
3801  *
3802  * fresh skbs have their ip_summed set to CHECKSUM_NONE.
3803  * Instead of forcing ip_summed to CHECKSUM_NONE, we can
3804  * use this helper, to document places where we make this assertion.
3805  */
3806 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
3807 {
3808 #ifdef DEBUG
3809         BUG_ON(skb->ip_summed != CHECKSUM_NONE);
3810 #endif
3811 }
3812 
3813 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
3814 
3815 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
3816 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
3817                                      unsigned int transport_len,
3818                                      __sum16(*skb_chkf)(struct sk_buff *skb));
3819 
3820 /**
3821  * skb_head_is_locked - Determine if the skb->head is locked down
3822  * @skb: skb to check
3823  *
3824  * The head on skbs build around a head frag can be removed if they are
3825  * not cloned.  This function returns true if the skb head is locked down
3826  * due to either being allocated via kmalloc, or by being a clone with
3827  * multiple references to the head.
3828  */
3829 static inline bool skb_head_is_locked(const struct sk_buff *skb)
3830 {
3831         return !skb->head_frag || skb_cloned(skb);
3832 }
3833 
3834 /**
3835  * skb_gso_network_seglen - Return length of individual segments of a gso packet
3836  *
3837  * @skb: GSO skb
3838  *
3839  * skb_gso_network_seglen is used to determine the real size of the
3840  * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
3841  *
3842  * The MAC/L2 header is not accounted for.
3843  */
3844 static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
3845 {
3846         unsigned int hdr_len = skb_transport_header(skb) -
3847                                skb_network_header(skb);
3848         return hdr_len + skb_gso_transport_seglen(skb);
3849 }
3850 
3851 /* Local Checksum Offload.
3852  * Compute outer checksum based on the assumption that the
3853  * inner checksum will be offloaded later.
3854  * See Documentation/networking/checksum-offloads.txt for
3855  * explanation of how this works.
3856  * Fill in outer checksum adjustment (e.g. with sum of outer
3857  * pseudo-header) before calling.
3858  * Also ensure that inner checksum is in linear data area.
3859  */
3860 static inline __wsum lco_csum(struct sk_buff *skb)
3861 {
3862         unsigned char *csum_start = skb_checksum_start(skb);
3863         unsigned char *l4_hdr = skb_transport_header(skb);
3864         __wsum partial;
3865 
3866         /* Start with complement of inner checksum adjustment */
3867         partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
3868                                                     skb->csum_offset));
3869 
3870         /* Add in checksum of our headers (incl. outer checksum
3871          * adjustment filled in by caller) and return result.
3872          */
3873         return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
3874 }
3875 
3876 #endif  /* __KERNEL__ */
3877 #endif  /* _LINUX_SKBUFF_H */
3878 

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