Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

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 
649         union {
650                 struct net_device       *dev;
651                 /* Some protocols might use this space to store information,
652                  * while device pointer would be NULL.
653                  * UDP receive path is one user.
654                  */
655                 unsigned long           dev_scratch;
656         };
657         /*
658          * This is the control buffer. It is free to use for every
659          * layer. Please put your private variables there. If you
660          * want to keep them across layers you have to do a skb_clone()
661          * first. This is owned by whoever has the skb queued ATM.
662          */
663         char                    cb[48] __aligned(8);
664 
665         unsigned long           _skb_refdst;
666         void                    (*destructor)(struct sk_buff *skb);
667 #ifdef CONFIG_XFRM
668         struct  sec_path        *sp;
669 #endif
670 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
671         struct nf_conntrack     *nfct;
672 #endif
673 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
674         struct nf_bridge_info   *nf_bridge;
675 #endif
676         unsigned int            len,
677                                 data_len;
678         __u16                   mac_len,
679                                 hdr_len;
680 
681         /* Following fields are _not_ copied in __copy_skb_header()
682          * Note that queue_mapping is here mostly to fill a hole.
683          */
684         kmemcheck_bitfield_begin(flags1);
685         __u16                   queue_mapping;
686 
687 /* if you move cloned around you also must adapt those constants */
688 #ifdef __BIG_ENDIAN_BITFIELD
689 #define CLONED_MASK     (1 << 7)
690 #else
691 #define CLONED_MASK     1
692 #endif
693 #define CLONED_OFFSET()         offsetof(struct sk_buff, __cloned_offset)
694 
695         __u8                    __cloned_offset[0];
696         __u8                    cloned:1,
697                                 nohdr:1,
698                                 fclone:2,
699                                 peeked:1,
700                                 head_frag:1,
701                                 xmit_more:1,
702                                 __unused:1; /* one bit hole */
703         kmemcheck_bitfield_end(flags1);
704 
705         /* fields enclosed in headers_start/headers_end are copied
706          * using a single memcpy() in __copy_skb_header()
707          */
708         /* private: */
709         __u32                   headers_start[0];
710         /* public: */
711 
712 /* if you move pkt_type around you also must adapt those constants */
713 #ifdef __BIG_ENDIAN_BITFIELD
714 #define PKT_TYPE_MAX    (7 << 5)
715 #else
716 #define PKT_TYPE_MAX    7
717 #endif
718 #define PKT_TYPE_OFFSET()       offsetof(struct sk_buff, __pkt_type_offset)
719 
720         __u8                    __pkt_type_offset[0];
721         __u8                    pkt_type:3;
722         __u8                    pfmemalloc:1;
723         __u8                    ignore_df:1;
724         __u8                    nfctinfo:3;
725 
726         __u8                    nf_trace:1;
727         __u8                    ip_summed:2;
728         __u8                    ooo_okay:1;
729         __u8                    l4_hash:1;
730         __u8                    sw_hash:1;
731         __u8                    wifi_acked_valid:1;
732         __u8                    wifi_acked:1;
733 
734         __u8                    no_fcs:1;
735         /* Indicates the inner headers are valid in the skbuff. */
736         __u8                    encapsulation:1;
737         __u8                    encap_hdr_csum:1;
738         __u8                    csum_valid:1;
739         __u8                    csum_complete_sw:1;
740         __u8                    csum_level:2;
741         __u8                    csum_bad:1;
742 
743 #ifdef CONFIG_IPV6_NDISC_NODETYPE
744         __u8                    ndisc_nodetype:2;
745 #endif
746         __u8                    ipvs_property:1;
747         __u8                    inner_protocol_type:1;
748         __u8                    remcsum_offload:1;
749 #ifdef CONFIG_NET_SWITCHDEV
750         __u8                    offload_fwd_mark:1;
751 #endif
752         /* 2, 4 or 5 bit hole */
753 
754 #ifdef CONFIG_NET_SCHED
755         __u16                   tc_index;       /* traffic control index */
756 #ifdef CONFIG_NET_CLS_ACT
757         __u16                   tc_verd;        /* traffic control verdict */
758 #endif
759 #endif
760 
761         union {
762                 __wsum          csum;
763                 struct {
764                         __u16   csum_start;
765                         __u16   csum_offset;
766                 };
767         };
768         __u32                   priority;
769         int                     skb_iif;
770         __u32                   hash;
771         __be16                  vlan_proto;
772         __u16                   vlan_tci;
773 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
774         union {
775                 unsigned int    napi_id;
776                 unsigned int    sender_cpu;
777         };
778 #endif
779 #ifdef CONFIG_NETWORK_SECMARK
780         __u32           secmark;
781 #endif
782 
783         union {
784                 __u32           mark;
785                 __u32           reserved_tailroom;
786         };
787 
788         union {
789                 __be16          inner_protocol;
790                 __u8            inner_ipproto;
791         };
792 
793         __u16                   inner_transport_header;
794         __u16                   inner_network_header;
795         __u16                   inner_mac_header;
796 
797         __be16                  protocol;
798         __u16                   transport_header;
799         __u16                   network_header;
800         __u16                   mac_header;
801 
802         /* private: */
803         __u32                   headers_end[0];
804         /* public: */
805 
806         /* These elements must be at the end, see alloc_skb() for details.  */
807         sk_buff_data_t          tail;
808         sk_buff_data_t          end;
809         unsigned char           *head,
810                                 *data;
811         unsigned int            truesize;
812         atomic_t                users;
813 };
814 
815 #ifdef __KERNEL__
816 /*
817  *      Handling routines are only of interest to the kernel
818  */
819 #include <linux/slab.h>
820 
821 
822 #define SKB_ALLOC_FCLONE        0x01
823 #define SKB_ALLOC_RX            0x02
824 #define SKB_ALLOC_NAPI          0x04
825 
826 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
827 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
828 {
829         return unlikely(skb->pfmemalloc);
830 }
831 
832 /*
833  * skb might have a dst pointer attached, refcounted or not.
834  * _skb_refdst low order bit is set if refcount was _not_ taken
835  */
836 #define SKB_DST_NOREF   1UL
837 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
838 
839 /**
840  * skb_dst - returns skb dst_entry
841  * @skb: buffer
842  *
843  * Returns skb dst_entry, regardless of reference taken or not.
844  */
845 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
846 {
847         /* If refdst was not refcounted, check we still are in a 
848          * rcu_read_lock section
849          */
850         WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
851                 !rcu_read_lock_held() &&
852                 !rcu_read_lock_bh_held());
853         return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
854 }
855 
856 /**
857  * skb_dst_set - sets skb dst
858  * @skb: buffer
859  * @dst: dst entry
860  *
861  * Sets skb dst, assuming a reference was taken on dst and should
862  * be released by skb_dst_drop()
863  */
864 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
865 {
866         skb->_skb_refdst = (unsigned long)dst;
867 }
868 
869 /**
870  * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
871  * @skb: buffer
872  * @dst: dst entry
873  *
874  * Sets skb dst, assuming a reference was not taken on dst.
875  * If dst entry is cached, we do not take reference and dst_release
876  * will be avoided by refdst_drop. If dst entry is not cached, we take
877  * reference, so that last dst_release can destroy the dst immediately.
878  */
879 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
880 {
881         WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
882         skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
883 }
884 
885 /**
886  * skb_dst_is_noref - Test if skb dst isn't refcounted
887  * @skb: buffer
888  */
889 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
890 {
891         return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
892 }
893 
894 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
895 {
896         return (struct rtable *)skb_dst(skb);
897 }
898 
899 /* For mangling skb->pkt_type from user space side from applications
900  * such as nft, tc, etc, we only allow a conservative subset of
901  * possible pkt_types to be set.
902 */
903 static inline bool skb_pkt_type_ok(u32 ptype)
904 {
905         return ptype <= PACKET_OTHERHOST;
906 }
907 
908 void kfree_skb(struct sk_buff *skb);
909 void kfree_skb_list(struct sk_buff *segs);
910 void skb_tx_error(struct sk_buff *skb);
911 void consume_skb(struct sk_buff *skb);
912 void  __kfree_skb(struct sk_buff *skb);
913 extern struct kmem_cache *skbuff_head_cache;
914 
915 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
916 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
917                       bool *fragstolen, int *delta_truesize);
918 
919 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
920                             int node);
921 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
922 struct sk_buff *build_skb(void *data, unsigned int frag_size);
923 static inline struct sk_buff *alloc_skb(unsigned int size,
924                                         gfp_t priority)
925 {
926         return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
927 }
928 
929 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
930                                      unsigned long data_len,
931                                      int max_page_order,
932                                      int *errcode,
933                                      gfp_t gfp_mask);
934 
935 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
936 struct sk_buff_fclones {
937         struct sk_buff  skb1;
938 
939         struct sk_buff  skb2;
940 
941         atomic_t        fclone_ref;
942 };
943 
944 /**
945  *      skb_fclone_busy - check if fclone is busy
946  *      @sk: socket
947  *      @skb: buffer
948  *
949  * Returns true if skb is a fast clone, and its clone is not freed.
950  * Some drivers call skb_orphan() in their ndo_start_xmit(),
951  * so we also check that this didnt happen.
952  */
953 static inline bool skb_fclone_busy(const struct sock *sk,
954                                    const struct sk_buff *skb)
955 {
956         const struct sk_buff_fclones *fclones;
957 
958         fclones = container_of(skb, struct sk_buff_fclones, skb1);
959 
960         return skb->fclone == SKB_FCLONE_ORIG &&
961                atomic_read(&fclones->fclone_ref) > 1 &&
962                fclones->skb2.sk == sk;
963 }
964 
965 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
966                                                gfp_t priority)
967 {
968         return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
969 }
970 
971 struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
972 static inline struct sk_buff *alloc_skb_head(gfp_t priority)
973 {
974         return __alloc_skb_head(priority, -1);
975 }
976 
977 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
978 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
979 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
980 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
981 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
982                                    gfp_t gfp_mask, bool fclone);
983 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
984                                           gfp_t gfp_mask)
985 {
986         return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
987 }
988 
989 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
990 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
991                                      unsigned int headroom);
992 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
993                                 int newtailroom, gfp_t priority);
994 int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
995                         int offset, int len);
996 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
997                  int len);
998 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
999 int skb_pad(struct sk_buff *skb, int pad);
1000 #define dev_kfree_skb(a)        consume_skb(a)
1001 
1002 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
1003                             int getfrag(void *from, char *to, int offset,
1004                                         int len, int odd, struct sk_buff *skb),
1005                             void *from, int length);
1006 
1007 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1008                          int offset, size_t size);
1009 
1010 struct skb_seq_state {
1011         __u32           lower_offset;
1012         __u32           upper_offset;
1013         __u32           frag_idx;
1014         __u32           stepped_offset;
1015         struct sk_buff  *root_skb;
1016         struct sk_buff  *cur_skb;
1017         __u8            *frag_data;
1018 };
1019 
1020 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1021                           unsigned int to, struct skb_seq_state *st);
1022 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1023                           struct skb_seq_state *st);
1024 void skb_abort_seq_read(struct skb_seq_state *st);
1025 
1026 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1027                            unsigned int to, struct ts_config *config);
1028 
1029 /*
1030  * Packet hash types specify the type of hash in skb_set_hash.
1031  *
1032  * Hash types refer to the protocol layer addresses which are used to
1033  * construct a packet's hash. The hashes are used to differentiate or identify
1034  * flows of the protocol layer for the hash type. Hash types are either
1035  * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1036  *
1037  * Properties of hashes:
1038  *
1039  * 1) Two packets in different flows have different hash values
1040  * 2) Two packets in the same flow should have the same hash value
1041  *
1042  * A hash at a higher layer is considered to be more specific. A driver should
1043  * set the most specific hash possible.
1044  *
1045  * A driver cannot indicate a more specific hash than the layer at which a hash
1046  * was computed. For instance an L3 hash cannot be set as an L4 hash.
1047  *
1048  * A driver may indicate a hash level which is less specific than the
1049  * actual layer the hash was computed on. For instance, a hash computed
1050  * at L4 may be considered an L3 hash. This should only be done if the
1051  * driver can't unambiguously determine that the HW computed the hash at
1052  * the higher layer. Note that the "should" in the second property above
1053  * permits this.
1054  */
1055 enum pkt_hash_types {
1056         PKT_HASH_TYPE_NONE,     /* Undefined type */
1057         PKT_HASH_TYPE_L2,       /* Input: src_MAC, dest_MAC */
1058         PKT_HASH_TYPE_L3,       /* Input: src_IP, dst_IP */
1059         PKT_HASH_TYPE_L4,       /* Input: src_IP, dst_IP, src_port, dst_port */
1060 };
1061 
1062 static inline void skb_clear_hash(struct sk_buff *skb)
1063 {
1064         skb->hash = 0;
1065         skb->sw_hash = 0;
1066         skb->l4_hash = 0;
1067 }
1068 
1069 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1070 {
1071         if (!skb->l4_hash)
1072                 skb_clear_hash(skb);
1073 }
1074 
1075 static inline void
1076 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1077 {
1078         skb->l4_hash = is_l4;
1079         skb->sw_hash = is_sw;
1080         skb->hash = hash;
1081 }
1082 
1083 static inline void
1084 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1085 {
1086         /* Used by drivers to set hash from HW */
1087         __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1088 }
1089 
1090 static inline void
1091 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1092 {
1093         __skb_set_hash(skb, hash, true, is_l4);
1094 }
1095 
1096 void __skb_get_hash(struct sk_buff *skb);
1097 u32 __skb_get_hash_symmetric(const struct sk_buff *skb);
1098 u32 skb_get_poff(const struct sk_buff *skb);
1099 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1100                    const struct flow_keys *keys, int hlen);
1101 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1102                             void *data, int hlen_proto);
1103 
1104 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1105                                         int thoff, u8 ip_proto)
1106 {
1107         return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1108 }
1109 
1110 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1111                              const struct flow_dissector_key *key,
1112                              unsigned int key_count);
1113 
1114 bool __skb_flow_dissect(const struct sk_buff *skb,
1115                         struct flow_dissector *flow_dissector,
1116                         void *target_container,
1117                         void *data, __be16 proto, int nhoff, int hlen,
1118                         unsigned int flags);
1119 
1120 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1121                                     struct flow_dissector *flow_dissector,
1122                                     void *target_container, unsigned int flags)
1123 {
1124         return __skb_flow_dissect(skb, flow_dissector, target_container,
1125                                   NULL, 0, 0, 0, flags);
1126 }
1127 
1128 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1129                                               struct flow_keys *flow,
1130                                               unsigned int flags)
1131 {
1132         memset(flow, 0, sizeof(*flow));
1133         return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
1134                                   NULL, 0, 0, 0, flags);
1135 }
1136 
1137 static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
1138                                                   void *data, __be16 proto,
1139                                                   int nhoff, int hlen,
1140                                                   unsigned int flags)
1141 {
1142         memset(flow, 0, sizeof(*flow));
1143         return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
1144                                   data, proto, nhoff, hlen, flags);
1145 }
1146 
1147 static inline __u32 skb_get_hash(struct sk_buff *skb)
1148 {
1149         if (!skb->l4_hash && !skb->sw_hash)
1150                 __skb_get_hash(skb);
1151 
1152         return skb->hash;
1153 }
1154 
1155 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6);
1156 
1157 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1158 {
1159         if (!skb->l4_hash && !skb->sw_hash) {
1160                 struct flow_keys keys;
1161                 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1162 
1163                 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1164         }
1165 
1166         return skb->hash;
1167 }
1168 
1169 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl);
1170 
1171 static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
1172 {
1173         if (!skb->l4_hash && !skb->sw_hash) {
1174                 struct flow_keys keys;
1175                 __u32 hash = __get_hash_from_flowi4(fl4, &keys);
1176 
1177                 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1178         }
1179 
1180         return skb->hash;
1181 }
1182 
1183 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1184 
1185 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1186 {
1187         return skb->hash;
1188 }
1189 
1190 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1191 {
1192         to->hash = from->hash;
1193         to->sw_hash = from->sw_hash;
1194         to->l4_hash = from->l4_hash;
1195 };
1196 
1197 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1198 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1199 {
1200         return skb->head + skb->end;
1201 }
1202 
1203 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1204 {
1205         return skb->end;
1206 }
1207 #else
1208 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1209 {
1210         return skb->end;
1211 }
1212 
1213 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1214 {
1215         return skb->end - skb->head;
1216 }
1217 #endif
1218 
1219 /* Internal */
1220 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1221 
1222 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1223 {
1224         return &skb_shinfo(skb)->hwtstamps;
1225 }
1226 
1227 /**
1228  *      skb_queue_empty - check if a queue is empty
1229  *      @list: queue head
1230  *
1231  *      Returns true if the queue is empty, false otherwise.
1232  */
1233 static inline int skb_queue_empty(const struct sk_buff_head *list)
1234 {
1235         return list->next == (const struct sk_buff *) list;
1236 }
1237 
1238 /**
1239  *      skb_queue_is_last - check if skb is the last entry in the queue
1240  *      @list: queue head
1241  *      @skb: buffer
1242  *
1243  *      Returns true if @skb is the last buffer on the list.
1244  */
1245 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1246                                      const struct sk_buff *skb)
1247 {
1248         return skb->next == (const struct sk_buff *) list;
1249 }
1250 
1251 /**
1252  *      skb_queue_is_first - check if skb is the first entry in the queue
1253  *      @list: queue head
1254  *      @skb: buffer
1255  *
1256  *      Returns true if @skb is the first buffer on the list.
1257  */
1258 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1259                                       const struct sk_buff *skb)
1260 {
1261         return skb->prev == (const struct sk_buff *) list;
1262 }
1263 
1264 /**
1265  *      skb_queue_next - return the next packet in the queue
1266  *      @list: queue head
1267  *      @skb: current buffer
1268  *
1269  *      Return the next packet in @list after @skb.  It is only valid to
1270  *      call this if skb_queue_is_last() evaluates to false.
1271  */
1272 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1273                                              const struct sk_buff *skb)
1274 {
1275         /* This BUG_ON may seem severe, but if we just return then we
1276          * are going to dereference garbage.
1277          */
1278         BUG_ON(skb_queue_is_last(list, skb));
1279         return skb->next;
1280 }
1281 
1282 /**
1283  *      skb_queue_prev - return the prev packet in the queue
1284  *      @list: queue head
1285  *      @skb: current buffer
1286  *
1287  *      Return the prev packet in @list before @skb.  It is only valid to
1288  *      call this if skb_queue_is_first() evaluates to false.
1289  */
1290 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1291                                              const struct sk_buff *skb)
1292 {
1293         /* This BUG_ON may seem severe, but if we just return then we
1294          * are going to dereference garbage.
1295          */
1296         BUG_ON(skb_queue_is_first(list, skb));
1297         return skb->prev;
1298 }
1299 
1300 /**
1301  *      skb_get - reference buffer
1302  *      @skb: buffer to reference
1303  *
1304  *      Makes another reference to a socket buffer and returns a pointer
1305  *      to the buffer.
1306  */
1307 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1308 {
1309         atomic_inc(&skb->users);
1310         return skb;
1311 }
1312 
1313 /*
1314  * If users == 1, we are the only owner and are can avoid redundant
1315  * atomic change.
1316  */
1317 
1318 /**
1319  *      skb_cloned - is the buffer a clone
1320  *      @skb: buffer to check
1321  *
1322  *      Returns true if the buffer was generated with skb_clone() and is
1323  *      one of multiple shared copies of the buffer. Cloned buffers are
1324  *      shared data so must not be written to under normal circumstances.
1325  */
1326 static inline int skb_cloned(const struct sk_buff *skb)
1327 {
1328         return skb->cloned &&
1329                (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1330 }
1331 
1332 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1333 {
1334         might_sleep_if(gfpflags_allow_blocking(pri));
1335 
1336         if (skb_cloned(skb))
1337                 return pskb_expand_head(skb, 0, 0, pri);
1338 
1339         return 0;
1340 }
1341 
1342 /**
1343  *      skb_header_cloned - is the header a clone
1344  *      @skb: buffer to check
1345  *
1346  *      Returns true if modifying the header part of the buffer requires
1347  *      the data to be copied.
1348  */
1349 static inline int skb_header_cloned(const struct sk_buff *skb)
1350 {
1351         int dataref;
1352 
1353         if (!skb->cloned)
1354                 return 0;
1355 
1356         dataref = atomic_read(&skb_shinfo(skb)->dataref);
1357         dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1358         return dataref != 1;
1359 }
1360 
1361 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
1362 {
1363         might_sleep_if(gfpflags_allow_blocking(pri));
1364 
1365         if (skb_header_cloned(skb))
1366                 return pskb_expand_head(skb, 0, 0, pri);
1367 
1368         return 0;
1369 }
1370 
1371 /**
1372  *      skb_header_release - release reference to header
1373  *      @skb: buffer to operate on
1374  *
1375  *      Drop a reference to the header part of the buffer.  This is done
1376  *      by acquiring a payload reference.  You must not read from the header
1377  *      part of skb->data after this.
1378  *      Note : Check if you can use __skb_header_release() instead.
1379  */
1380 static inline void skb_header_release(struct sk_buff *skb)
1381 {
1382         BUG_ON(skb->nohdr);
1383         skb->nohdr = 1;
1384         atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
1385 }
1386 
1387 /**
1388  *      __skb_header_release - release reference to header
1389  *      @skb: buffer to operate on
1390  *
1391  *      Variant of skb_header_release() assuming skb is private to caller.
1392  *      We can avoid one atomic operation.
1393  */
1394 static inline void __skb_header_release(struct sk_buff *skb)
1395 {
1396         skb->nohdr = 1;
1397         atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1398 }
1399 
1400 
1401 /**
1402  *      skb_shared - is the buffer shared
1403  *      @skb: buffer to check
1404  *
1405  *      Returns true if more than one person has a reference to this
1406  *      buffer.
1407  */
1408 static inline int skb_shared(const struct sk_buff *skb)
1409 {
1410         return atomic_read(&skb->users) != 1;
1411 }
1412 
1413 /**
1414  *      skb_share_check - check if buffer is shared and if so clone it
1415  *      @skb: buffer to check
1416  *      @pri: priority for memory allocation
1417  *
1418  *      If the buffer is shared the buffer is cloned and the old copy
1419  *      drops a reference. A new clone with a single reference is returned.
1420  *      If the buffer is not shared the original buffer is returned. When
1421  *      being called from interrupt status or with spinlocks held pri must
1422  *      be GFP_ATOMIC.
1423  *
1424  *      NULL is returned on a memory allocation failure.
1425  */
1426 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1427 {
1428         might_sleep_if(gfpflags_allow_blocking(pri));
1429         if (skb_shared(skb)) {
1430                 struct sk_buff *nskb = skb_clone(skb, pri);
1431 
1432                 if (likely(nskb))
1433                         consume_skb(skb);
1434                 else
1435                         kfree_skb(skb);
1436                 skb = nskb;
1437         }
1438         return skb;
1439 }
1440 
1441 /*
1442  *      Copy shared buffers into a new sk_buff. We effectively do COW on
1443  *      packets to handle cases where we have a local reader and forward
1444  *      and a couple of other messy ones. The normal one is tcpdumping
1445  *      a packet thats being forwarded.
1446  */
1447 
1448 /**
1449  *      skb_unshare - make a copy of a shared buffer
1450  *      @skb: buffer to check
1451  *      @pri: priority for memory allocation
1452  *
1453  *      If the socket buffer is a clone then this function creates a new
1454  *      copy of the data, drops a reference count on the old copy and returns
1455  *      the new copy with the reference count at 1. If the buffer is not a clone
1456  *      the original buffer is returned. When called with a spinlock held or
1457  *      from interrupt state @pri must be %GFP_ATOMIC
1458  *
1459  *      %NULL is returned on a memory allocation failure.
1460  */
1461 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1462                                           gfp_t pri)
1463 {
1464         might_sleep_if(gfpflags_allow_blocking(pri));
1465         if (skb_cloned(skb)) {
1466                 struct sk_buff *nskb = skb_copy(skb, pri);
1467 
1468                 /* Free our shared copy */
1469                 if (likely(nskb))
1470                         consume_skb(skb);
1471                 else
1472                         kfree_skb(skb);
1473                 skb = nskb;
1474         }
1475         return skb;
1476 }
1477 
1478 /**
1479  *      skb_peek - peek at the head of an &sk_buff_head
1480  *      @list_: list to peek at
1481  *
1482  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1483  *      be careful with this one. A peek leaves the buffer on the
1484  *      list and someone else may run off with it. You must hold
1485  *      the appropriate locks or have a private queue to do this.
1486  *
1487  *      Returns %NULL for an empty list or a pointer to the head element.
1488  *      The reference count is not incremented and the reference is therefore
1489  *      volatile. Use with caution.
1490  */
1491 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1492 {
1493         struct sk_buff *skb = list_->next;
1494 
1495         if (skb == (struct sk_buff *)list_)
1496                 skb = NULL;
1497         return skb;
1498 }
1499 
1500 /**
1501  *      skb_peek_next - peek skb following the given one from a queue
1502  *      @skb: skb to start from
1503  *      @list_: list to peek at
1504  *
1505  *      Returns %NULL when the end of the list is met or a pointer to the
1506  *      next element. The reference count is not incremented and the
1507  *      reference is therefore volatile. Use with caution.
1508  */
1509 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1510                 const struct sk_buff_head *list_)
1511 {
1512         struct sk_buff *next = skb->next;
1513 
1514         if (next == (struct sk_buff *)list_)
1515                 next = NULL;
1516         return next;
1517 }
1518 
1519 /**
1520  *      skb_peek_tail - peek at the tail of an &sk_buff_head
1521  *      @list_: list to peek at
1522  *
1523  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1524  *      be careful with this one. A peek leaves the buffer on the
1525  *      list and someone else may run off with it. You must hold
1526  *      the appropriate locks or have a private queue to do this.
1527  *
1528  *      Returns %NULL for an empty list or a pointer to the tail element.
1529  *      The reference count is not incremented and the reference is therefore
1530  *      volatile. Use with caution.
1531  */
1532 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1533 {
1534         struct sk_buff *skb = list_->prev;
1535 
1536         if (skb == (struct sk_buff *)list_)
1537                 skb = NULL;
1538         return skb;
1539 
1540 }
1541 
1542 /**
1543  *      skb_queue_len   - get queue length
1544  *      @list_: list to measure
1545  *
1546  *      Return the length of an &sk_buff queue.
1547  */
1548 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1549 {
1550         return list_->qlen;
1551 }
1552 
1553 /**
1554  *      __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1555  *      @list: queue to initialize
1556  *
1557  *      This initializes only the list and queue length aspects of
1558  *      an sk_buff_head object.  This allows to initialize the list
1559  *      aspects of an sk_buff_head without reinitializing things like
1560  *      the spinlock.  It can also be used for on-stack sk_buff_head
1561  *      objects where the spinlock is known to not be used.
1562  */
1563 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1564 {
1565         list->prev = list->next = (struct sk_buff *)list;
1566         list->qlen = 0;
1567 }
1568 
1569 /*
1570  * This function creates a split out lock class for each invocation;
1571  * this is needed for now since a whole lot of users of the skb-queue
1572  * infrastructure in drivers have different locking usage (in hardirq)
1573  * than the networking core (in softirq only). In the long run either the
1574  * network layer or drivers should need annotation to consolidate the
1575  * main types of usage into 3 classes.
1576  */
1577 static inline void skb_queue_head_init(struct sk_buff_head *list)
1578 {
1579         spin_lock_init(&list->lock);
1580         __skb_queue_head_init(list);
1581 }
1582 
1583 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1584                 struct lock_class_key *class)
1585 {
1586         skb_queue_head_init(list);
1587         lockdep_set_class(&list->lock, class);
1588 }
1589 
1590 /*
1591  *      Insert an sk_buff on a list.
1592  *
1593  *      The "__skb_xxxx()" functions are the non-atomic ones that
1594  *      can only be called with interrupts disabled.
1595  */
1596 void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
1597                 struct sk_buff_head *list);
1598 static inline void __skb_insert(struct sk_buff *newsk,
1599                                 struct sk_buff *prev, struct sk_buff *next,
1600                                 struct sk_buff_head *list)
1601 {
1602         newsk->next = next;
1603         newsk->prev = prev;
1604         next->prev  = prev->next = newsk;
1605         list->qlen++;
1606 }
1607 
1608 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1609                                       struct sk_buff *prev,
1610                                       struct sk_buff *next)
1611 {
1612         struct sk_buff *first = list->next;
1613         struct sk_buff *last = list->prev;
1614 
1615         first->prev = prev;
1616         prev->next = first;
1617 
1618         last->next = next;
1619         next->prev = last;
1620 }
1621 
1622 /**
1623  *      skb_queue_splice - join two skb lists, this is designed for stacks
1624  *      @list: the new list to add
1625  *      @head: the place to add it in the first list
1626  */
1627 static inline void skb_queue_splice(const struct sk_buff_head *list,
1628                                     struct sk_buff_head *head)
1629 {
1630         if (!skb_queue_empty(list)) {
1631                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1632                 head->qlen += list->qlen;
1633         }
1634 }
1635 
1636 /**
1637  *      skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1638  *      @list: the new list to add
1639  *      @head: the place to add it in the first list
1640  *
1641  *      The list at @list is reinitialised
1642  */
1643 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1644                                          struct sk_buff_head *head)
1645 {
1646         if (!skb_queue_empty(list)) {
1647                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1648                 head->qlen += list->qlen;
1649                 __skb_queue_head_init(list);
1650         }
1651 }
1652 
1653 /**
1654  *      skb_queue_splice_tail - join two skb lists, each list being a queue
1655  *      @list: the new list to add
1656  *      @head: the place to add it in the first list
1657  */
1658 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1659                                          struct sk_buff_head *head)
1660 {
1661         if (!skb_queue_empty(list)) {
1662                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1663                 head->qlen += list->qlen;
1664         }
1665 }
1666 
1667 /**
1668  *      skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1669  *      @list: the new list to add
1670  *      @head: the place to add it in the first list
1671  *
1672  *      Each of the lists is a queue.
1673  *      The list at @list is reinitialised
1674  */
1675 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1676                                               struct sk_buff_head *head)
1677 {
1678         if (!skb_queue_empty(list)) {
1679                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1680                 head->qlen += list->qlen;
1681                 __skb_queue_head_init(list);
1682         }
1683 }
1684 
1685 /**
1686  *      __skb_queue_after - queue a buffer at the list head
1687  *      @list: list to use
1688  *      @prev: place after this buffer
1689  *      @newsk: buffer to queue
1690  *
1691  *      Queue a buffer int the middle of a list. This function takes no locks
1692  *      and you must therefore hold required locks before calling it.
1693  *
1694  *      A buffer cannot be placed on two lists at the same time.
1695  */
1696 static inline void __skb_queue_after(struct sk_buff_head *list,
1697                                      struct sk_buff *prev,
1698                                      struct sk_buff *newsk)
1699 {
1700         __skb_insert(newsk, prev, prev->next, list);
1701 }
1702 
1703 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1704                 struct sk_buff_head *list);
1705 
1706 static inline void __skb_queue_before(struct sk_buff_head *list,
1707                                       struct sk_buff *next,
1708                                       struct sk_buff *newsk)
1709 {
1710         __skb_insert(newsk, next->prev, next, list);
1711 }
1712 
1713 /**
1714  *      __skb_queue_head - queue a buffer at the list head
1715  *      @list: list to use
1716  *      @newsk: buffer to queue
1717  *
1718  *      Queue a buffer at the start of a list. This function takes no locks
1719  *      and you must therefore hold required locks before calling it.
1720  *
1721  *      A buffer cannot be placed on two lists at the same time.
1722  */
1723 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1724 static inline void __skb_queue_head(struct sk_buff_head *list,
1725                                     struct sk_buff *newsk)
1726 {
1727         __skb_queue_after(list, (struct sk_buff *)list, newsk);
1728 }
1729 
1730 /**
1731  *      __skb_queue_tail - queue a buffer at the list tail
1732  *      @list: list to use
1733  *      @newsk: buffer to queue
1734  *
1735  *      Queue a buffer at the end of a list. This function takes no locks
1736  *      and you must therefore hold required locks before calling it.
1737  *
1738  *      A buffer cannot be placed on two lists at the same time.
1739  */
1740 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1741 static inline void __skb_queue_tail(struct sk_buff_head *list,
1742                                    struct sk_buff *newsk)
1743 {
1744         __skb_queue_before(list, (struct sk_buff *)list, newsk);
1745 }
1746 
1747 /*
1748  * remove sk_buff from list. _Must_ be called atomically, and with
1749  * the list known..
1750  */
1751 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1752 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1753 {
1754         struct sk_buff *next, *prev;
1755 
1756         list->qlen--;
1757         next       = skb->next;
1758         prev       = skb->prev;
1759         skb->next  = skb->prev = NULL;
1760         next->prev = prev;
1761         prev->next = next;
1762 }
1763 
1764 /**
1765  *      __skb_dequeue - remove from the head of the queue
1766  *      @list: list to dequeue from
1767  *
1768  *      Remove the head of the list. This function does not take any locks
1769  *      so must be used with appropriate locks held only. The head item is
1770  *      returned or %NULL if the list is empty.
1771  */
1772 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1773 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1774 {
1775         struct sk_buff *skb = skb_peek(list);
1776         if (skb)
1777                 __skb_unlink(skb, list);
1778         return skb;
1779 }
1780 
1781 /**
1782  *      __skb_dequeue_tail - remove from the tail of the queue
1783  *      @list: list to dequeue from
1784  *
1785  *      Remove the tail of the list. This function does not take any locks
1786  *      so must be used with appropriate locks held only. The tail item is
1787  *      returned or %NULL if the list is empty.
1788  */
1789 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1790 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1791 {
1792         struct sk_buff *skb = skb_peek_tail(list);
1793         if (skb)
1794                 __skb_unlink(skb, list);
1795         return skb;
1796 }
1797 
1798 
1799 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1800 {
1801         return skb->data_len;
1802 }
1803 
1804 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1805 {
1806         return skb->len - skb->data_len;
1807 }
1808 
1809 static inline unsigned int skb_pagelen(const struct sk_buff *skb)
1810 {
1811         unsigned int i, len = 0;
1812 
1813         for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--)
1814                 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1815         return len + skb_headlen(skb);
1816 }
1817 
1818 /**
1819  * __skb_fill_page_desc - initialise a paged fragment in an skb
1820  * @skb: buffer containing fragment to be initialised
1821  * @i: paged fragment index to initialise
1822  * @page: the page to use for this fragment
1823  * @off: the offset to the data with @page
1824  * @size: the length of the data
1825  *
1826  * Initialises the @i'th fragment of @skb to point to &size bytes at
1827  * offset @off within @page.
1828  *
1829  * Does not take any additional reference on the fragment.
1830  */
1831 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1832                                         struct page *page, int off, int size)
1833 {
1834         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1835 
1836         /*
1837          * Propagate page pfmemalloc to the skb if we can. The problem is
1838          * that not all callers have unique ownership of the page but rely
1839          * on page_is_pfmemalloc doing the right thing(tm).
1840          */
1841         frag->page.p              = page;
1842         frag->page_offset         = off;
1843         skb_frag_size_set(frag, size);
1844 
1845         page = compound_head(page);
1846         if (page_is_pfmemalloc(page))
1847                 skb->pfmemalloc = true;
1848 }
1849 
1850 /**
1851  * skb_fill_page_desc - initialise a paged fragment in an skb
1852  * @skb: buffer containing fragment to be initialised
1853  * @i: paged fragment index to initialise
1854  * @page: the page to use for this fragment
1855  * @off: the offset to the data with @page
1856  * @size: the length of the data
1857  *
1858  * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1859  * @skb to point to @size bytes at offset @off within @page. In
1860  * addition updates @skb such that @i is the last fragment.
1861  *
1862  * Does not take any additional reference on the fragment.
1863  */
1864 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1865                                       struct page *page, int off, int size)
1866 {
1867         __skb_fill_page_desc(skb, i, page, off, size);
1868         skb_shinfo(skb)->nr_frags = i + 1;
1869 }
1870 
1871 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
1872                      int size, unsigned int truesize);
1873 
1874 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
1875                           unsigned int truesize);
1876 
1877 #define SKB_PAGE_ASSERT(skb)    BUG_ON(skb_shinfo(skb)->nr_frags)
1878 #define SKB_FRAG_ASSERT(skb)    BUG_ON(skb_has_frag_list(skb))
1879 #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
1880 
1881 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1882 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1883 {
1884         return skb->head + skb->tail;
1885 }
1886 
1887 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1888 {
1889         skb->tail = skb->data - skb->head;
1890 }
1891 
1892 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1893 {
1894         skb_reset_tail_pointer(skb);
1895         skb->tail += offset;
1896 }
1897 
1898 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1899 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1900 {
1901         return skb->tail;
1902 }
1903 
1904 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1905 {
1906         skb->tail = skb->data;
1907 }
1908 
1909 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1910 {
1911         skb->tail = skb->data + offset;
1912 }
1913 
1914 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1915 
1916 /*
1917  *      Add data to an sk_buff
1918  */
1919 unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
1920 unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1921 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1922 {
1923         unsigned char *tmp = skb_tail_pointer(skb);
1924         SKB_LINEAR_ASSERT(skb);
1925         skb->tail += len;
1926         skb->len  += len;
1927         return tmp;
1928 }
1929 
1930 unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1931 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1932 {
1933         skb->data -= len;
1934         skb->len  += len;
1935         return skb->data;
1936 }
1937 
1938 unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1939 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1940 {
1941         skb->len -= len;
1942         BUG_ON(skb->len < skb->data_len);
1943         return skb->data += len;
1944 }
1945 
1946 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1947 {
1948         return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1949 }
1950 
1951 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1952 
1953 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1954 {
1955         if (len > skb_headlen(skb) &&
1956             !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1957                 return NULL;
1958         skb->len -= len;
1959         return skb->data += len;
1960 }
1961 
1962 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1963 {
1964         return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1965 }
1966 
1967 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1968 {
1969         if (likely(len <= skb_headlen(skb)))
1970                 return 1;
1971         if (unlikely(len > skb->len))
1972                 return 0;
1973         return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1974 }
1975 
1976 void skb_condense(struct sk_buff *skb);
1977 
1978 /**
1979  *      skb_headroom - bytes at buffer head
1980  *      @skb: buffer to check
1981  *
1982  *      Return the number of bytes of free space at the head of an &sk_buff.
1983  */
1984 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1985 {
1986         return skb->data - skb->head;
1987 }
1988 
1989 /**
1990  *      skb_tailroom - bytes at buffer end
1991  *      @skb: buffer to check
1992  *
1993  *      Return the number of bytes of free space at the tail of an sk_buff
1994  */
1995 static inline int skb_tailroom(const struct sk_buff *skb)
1996 {
1997         return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1998 }
1999 
2000 /**
2001  *      skb_availroom - bytes at buffer end
2002  *      @skb: buffer to check
2003  *
2004  *      Return the number of bytes of free space at the tail of an sk_buff
2005  *      allocated by sk_stream_alloc()
2006  */
2007 static inline int skb_availroom(const struct sk_buff *skb)
2008 {
2009         if (skb_is_nonlinear(skb))
2010                 return 0;
2011 
2012         return skb->end - skb->tail - skb->reserved_tailroom;
2013 }
2014 
2015 /**
2016  *      skb_reserve - adjust headroom
2017  *      @skb: buffer to alter
2018  *      @len: bytes to move
2019  *
2020  *      Increase the headroom of an empty &sk_buff by reducing the tail
2021  *      room. This is only allowed for an empty buffer.
2022  */
2023 static inline void skb_reserve(struct sk_buff *skb, int len)
2024 {
2025         skb->data += len;
2026         skb->tail += len;
2027 }
2028 
2029 /**
2030  *      skb_tailroom_reserve - adjust reserved_tailroom
2031  *      @skb: buffer to alter
2032  *      @mtu: maximum amount of headlen permitted
2033  *      @needed_tailroom: minimum amount of reserved_tailroom
2034  *
2035  *      Set reserved_tailroom so that headlen can be as large as possible but
2036  *      not larger than mtu and tailroom cannot be smaller than
2037  *      needed_tailroom.
2038  *      The required headroom should already have been reserved before using
2039  *      this function.
2040  */
2041 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2042                                         unsigned int needed_tailroom)
2043 {
2044         SKB_LINEAR_ASSERT(skb);
2045         if (mtu < skb_tailroom(skb) - needed_tailroom)
2046                 /* use at most mtu */
2047                 skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2048         else
2049                 /* use up to all available space */
2050                 skb->reserved_tailroom = needed_tailroom;
2051 }
2052 
2053 #define ENCAP_TYPE_ETHER        0
2054 #define ENCAP_TYPE_IPPROTO      1
2055 
2056 static inline void skb_set_inner_protocol(struct sk_buff *skb,
2057                                           __be16 protocol)
2058 {
2059         skb->inner_protocol = protocol;
2060         skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2061 }
2062 
2063 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2064                                          __u8 ipproto)
2065 {
2066         skb->inner_ipproto = ipproto;
2067         skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2068 }
2069 
2070 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2071 {
2072         skb->inner_mac_header = skb->mac_header;
2073         skb->inner_network_header = skb->network_header;
2074         skb->inner_transport_header = skb->transport_header;
2075 }
2076 
2077 static inline void skb_reset_mac_len(struct sk_buff *skb)
2078 {
2079         skb->mac_len = skb->network_header - skb->mac_header;
2080 }
2081 
2082 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2083                                                         *skb)
2084 {
2085         return skb->head + skb->inner_transport_header;
2086 }
2087 
2088 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2089 {
2090         return skb_inner_transport_header(skb) - skb->data;
2091 }
2092 
2093 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2094 {
2095         skb->inner_transport_header = skb->data - skb->head;
2096 }
2097 
2098 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2099                                                    const int offset)
2100 {
2101         skb_reset_inner_transport_header(skb);
2102         skb->inner_transport_header += offset;
2103 }
2104 
2105 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2106 {
2107         return skb->head + skb->inner_network_header;
2108 }
2109 
2110 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2111 {
2112         skb->inner_network_header = skb->data - skb->head;
2113 }
2114 
2115 static inline void skb_set_inner_network_header(struct sk_buff *skb,
2116                                                 const int offset)
2117 {
2118         skb_reset_inner_network_header(skb);
2119         skb->inner_network_header += offset;
2120 }
2121 
2122 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2123 {
2124         return skb->head + skb->inner_mac_header;
2125 }
2126 
2127 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2128 {
2129         skb->inner_mac_header = skb->data - skb->head;
2130 }
2131 
2132 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2133                                             const int offset)
2134 {
2135         skb_reset_inner_mac_header(skb);
2136         skb->inner_mac_header += offset;
2137 }
2138 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2139 {
2140         return skb->transport_header != (typeof(skb->transport_header))~0U;
2141 }
2142 
2143 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2144 {
2145         return skb->head + skb->transport_header;
2146 }
2147 
2148 static inline void skb_reset_transport_header(struct sk_buff *skb)
2149 {
2150         skb->transport_header = skb->data - skb->head;
2151 }
2152 
2153 static inline void skb_set_transport_header(struct sk_buff *skb,
2154                                             const int offset)
2155 {
2156         skb_reset_transport_header(skb);
2157         skb->transport_header += offset;
2158 }
2159 
2160 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2161 {
2162         return skb->head + skb->network_header;
2163 }
2164 
2165 static inline void skb_reset_network_header(struct sk_buff *skb)
2166 {
2167         skb->network_header = skb->data - skb->head;
2168 }
2169 
2170 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2171 {
2172         skb_reset_network_header(skb);
2173         skb->network_header += offset;
2174 }
2175 
2176 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2177 {
2178         return skb->head + skb->mac_header;
2179 }
2180 
2181 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2182 {
2183         return skb->mac_header != (typeof(skb->mac_header))~0U;
2184 }
2185 
2186 static inline void skb_reset_mac_header(struct sk_buff *skb)
2187 {
2188         skb->mac_header = skb->data - skb->head;
2189 }
2190 
2191 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2192 {
2193         skb_reset_mac_header(skb);
2194         skb->mac_header += offset;
2195 }
2196 
2197 static inline void skb_pop_mac_header(struct sk_buff *skb)
2198 {
2199         skb->mac_header = skb->network_header;
2200 }
2201 
2202 static inline void skb_probe_transport_header(struct sk_buff *skb,
2203                                               const int offset_hint)
2204 {
2205         struct flow_keys keys;
2206 
2207         if (skb_transport_header_was_set(skb))
2208                 return;
2209         else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
2210                 skb_set_transport_header(skb, keys.control.thoff);
2211         else
2212                 skb_set_transport_header(skb, offset_hint);
2213 }
2214 
2215 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2216 {
2217         if (skb_mac_header_was_set(skb)) {
2218                 const unsigned char *old_mac = skb_mac_header(skb);
2219 
2220                 skb_set_mac_header(skb, -skb->mac_len);
2221                 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2222         }
2223 }
2224 
2225 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2226 {
2227         return skb->csum_start - skb_headroom(skb);
2228 }
2229 
2230 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
2231 {
2232         return skb->head + skb->csum_start;
2233 }
2234 
2235 static inline int skb_transport_offset(const struct sk_buff *skb)
2236 {
2237         return skb_transport_header(skb) - skb->data;
2238 }
2239 
2240 static inline u32 skb_network_header_len(const struct sk_buff *skb)
2241 {
2242         return skb->transport_header - skb->network_header;
2243 }
2244 
2245 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2246 {
2247         return skb->inner_transport_header - skb->inner_network_header;
2248 }
2249 
2250 static inline int skb_network_offset(const struct sk_buff *skb)
2251 {
2252         return skb_network_header(skb) - skb->data;
2253 }
2254 
2255 static inline int skb_inner_network_offset(const struct sk_buff *skb)
2256 {
2257         return skb_inner_network_header(skb) - skb->data;
2258 }
2259 
2260 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2261 {
2262         return pskb_may_pull(skb, skb_network_offset(skb) + len);
2263 }
2264 
2265 /*
2266  * CPUs often take a performance hit when accessing unaligned memory
2267  * locations. The actual performance hit varies, it can be small if the
2268  * hardware handles it or large if we have to take an exception and fix it
2269  * in software.
2270  *
2271  * Since an ethernet header is 14 bytes network drivers often end up with
2272  * the IP header at an unaligned offset. The IP header can be aligned by
2273  * shifting the start of the packet by 2 bytes. Drivers should do this
2274  * with:
2275  *
2276  * skb_reserve(skb, NET_IP_ALIGN);
2277  *
2278  * The downside to this alignment of the IP header is that the DMA is now
2279  * unaligned. On some architectures the cost of an unaligned DMA is high
2280  * and this cost outweighs the gains made by aligning the IP header.
2281  *
2282  * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2283  * to be overridden.
2284  */
2285 #ifndef NET_IP_ALIGN
2286 #define NET_IP_ALIGN    2
2287 #endif
2288 
2289 /*
2290  * The networking layer reserves some headroom in skb data (via
2291  * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2292  * the header has to grow. In the default case, if the header has to grow
2293  * 32 bytes or less we avoid the reallocation.
2294  *
2295  * Unfortunately this headroom changes the DMA alignment of the resulting
2296  * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2297  * on some architectures. An architecture can override this value,
2298  * perhaps setting it to a cacheline in size (since that will maintain
2299  * cacheline alignment of the DMA). It must be a power of 2.
2300  *
2301  * Various parts of the networking layer expect at least 32 bytes of
2302  * headroom, you should not reduce this.
2303  *
2304  * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2305  * to reduce average number of cache lines per packet.
2306  * get_rps_cpus() for example only access one 64 bytes aligned block :
2307  * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2308  */
2309 #ifndef NET_SKB_PAD
2310 #define NET_SKB_PAD     max(32, L1_CACHE_BYTES)
2311 #endif
2312 
2313 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2314 
2315 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
2316 {
2317         if (unlikely(skb_is_nonlinear(skb))) {
2318                 WARN_ON(1);
2319                 return;
2320         }
2321         skb->len = len;
2322         skb_set_tail_pointer(skb, len);
2323 }
2324 
2325 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2326 {
2327         __skb_set_length(skb, len);
2328 }
2329 
2330 void skb_trim(struct sk_buff *skb, unsigned int len);
2331 
2332 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2333 {
2334         if (skb->data_len)
2335                 return ___pskb_trim(skb, len);
2336         __skb_trim(skb, len);
2337         return 0;
2338 }
2339 
2340 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2341 {
2342         return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2343 }
2344 
2345 /**
2346  *      pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2347  *      @skb: buffer to alter
2348  *      @len: new length
2349  *
2350  *      This is identical to pskb_trim except that the caller knows that
2351  *      the skb is not cloned so we should never get an error due to out-
2352  *      of-memory.
2353  */
2354 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2355 {
2356         int err = pskb_trim(skb, len);
2357         BUG_ON(err);
2358 }
2359 
2360 static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
2361 {
2362         unsigned int diff = len - skb->len;
2363 
2364         if (skb_tailroom(skb) < diff) {
2365                 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
2366                                            GFP_ATOMIC);
2367                 if (ret)
2368                         return ret;
2369         }
2370         __skb_set_length(skb, len);
2371         return 0;
2372 }
2373 
2374 /**
2375  *      skb_orphan - orphan a buffer
2376  *      @skb: buffer to orphan
2377  *
2378  *      If a buffer currently has an owner then we call the owner's
2379  *      destructor function and make the @skb unowned. The buffer continues
2380  *      to exist but is no longer charged to its former owner.
2381  */
2382 static inline void skb_orphan(struct sk_buff *skb)
2383 {
2384         if (skb->destructor) {
2385                 skb->destructor(skb);
2386                 skb->destructor = NULL;
2387                 skb->sk         = NULL;
2388         } else {
2389                 BUG_ON(skb->sk);
2390         }
2391 }
2392 
2393 /**
2394  *      skb_orphan_frags - orphan the frags contained in a buffer
2395  *      @skb: buffer to orphan frags from
2396  *      @gfp_mask: allocation mask for replacement pages
2397  *
2398  *      For each frag in the SKB which needs a destructor (i.e. has an
2399  *      owner) create a copy of that frag and release the original
2400  *      page by calling the destructor.
2401  */
2402 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2403 {
2404         if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
2405                 return 0;
2406         return skb_copy_ubufs(skb, gfp_mask);
2407 }
2408 
2409 /**
2410  *      __skb_queue_purge - empty a list
2411  *      @list: list to empty
2412  *
2413  *      Delete all buffers on an &sk_buff list. Each buffer is removed from
2414  *      the list and one reference dropped. This function does not take the
2415  *      list lock and the caller must hold the relevant locks to use it.
2416  */
2417 void skb_queue_purge(struct sk_buff_head *list);
2418 static inline void __skb_queue_purge(struct sk_buff_head *list)
2419 {
2420         struct sk_buff *skb;
2421         while ((skb = __skb_dequeue(list)) != NULL)
2422                 kfree_skb(skb);
2423 }
2424 
2425 void skb_rbtree_purge(struct rb_root *root);
2426 
2427 void *netdev_alloc_frag(unsigned int fragsz);
2428 
2429 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2430                                    gfp_t gfp_mask);
2431 
2432 /**
2433  *      netdev_alloc_skb - allocate an skbuff for rx on a specific device
2434  *      @dev: network device to receive on
2435  *      @length: length to allocate
2436  *
2437  *      Allocate a new &sk_buff and assign it a usage count of one. The
2438  *      buffer has unspecified headroom built in. Users should allocate
2439  *      the headroom they think they need without accounting for the
2440  *      built in space. The built in space is used for optimisations.
2441  *
2442  *      %NULL is returned if there is no free memory. Although this function
2443  *      allocates memory it can be called from an interrupt.
2444  */
2445 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2446                                                unsigned int length)
2447 {
2448         return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2449 }
2450 
2451 /* legacy helper around __netdev_alloc_skb() */
2452 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2453                                               gfp_t gfp_mask)
2454 {
2455         return __netdev_alloc_skb(NULL, length, gfp_mask);
2456 }
2457 
2458 /* legacy helper around netdev_alloc_skb() */
2459 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2460 {
2461         return netdev_alloc_skb(NULL, length);
2462 }
2463 
2464 
2465 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2466                 unsigned int length, gfp_t gfp)
2467 {
2468         struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2469 
2470         if (NET_IP_ALIGN && skb)
2471                 skb_reserve(skb, NET_IP_ALIGN);
2472         return skb;
2473 }
2474 
2475 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2476                 unsigned int length)
2477 {
2478         return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2479 }
2480 
2481 static inline void skb_free_frag(void *addr)
2482 {
2483         page_frag_free(addr);
2484 }
2485 
2486 void *napi_alloc_frag(unsigned int fragsz);
2487 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2488                                  unsigned int length, gfp_t gfp_mask);
2489 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2490                                              unsigned int length)
2491 {
2492         return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2493 }
2494 void napi_consume_skb(struct sk_buff *skb, int budget);
2495 
2496 void __kfree_skb_flush(void);
2497 void __kfree_skb_defer(struct sk_buff *skb);
2498 
2499 /**
2500  * __dev_alloc_pages - allocate page for network Rx
2501  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2502  * @order: size of the allocation
2503  *
2504  * Allocate a new page.
2505  *
2506  * %NULL is returned if there is no free memory.
2507 */
2508 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2509                                              unsigned int order)
2510 {
2511         /* This piece of code contains several assumptions.
2512          * 1.  This is for device Rx, therefor a cold page is preferred.
2513          * 2.  The expectation is the user wants a compound page.
2514          * 3.  If requesting a order 0 page it will not be compound
2515          *     due to the check to see if order has a value in prep_new_page
2516          * 4.  __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2517          *     code in gfp_to_alloc_flags that should be enforcing this.
2518          */
2519         gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC;
2520 
2521         return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2522 }
2523 
2524 static inline struct page *dev_alloc_pages(unsigned int order)
2525 {
2526         return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
2527 }
2528 
2529 /**
2530  * __dev_alloc_page - allocate a page for network Rx
2531  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2532  *
2533  * Allocate a new page.
2534  *
2535  * %NULL is returned if there is no free memory.
2536  */
2537 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2538 {
2539         return __dev_alloc_pages(gfp_mask, 0);
2540 }
2541 
2542 static inline struct page *dev_alloc_page(void)
2543 {
2544         return dev_alloc_pages(0);
2545 }
2546 
2547 /**
2548  *      skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2549  *      @page: The page that was allocated from skb_alloc_page
2550  *      @skb: The skb that may need pfmemalloc set
2551  */
2552 static inline void skb_propagate_pfmemalloc(struct page *page,
2553                                              struct sk_buff *skb)
2554 {
2555         if (page_is_pfmemalloc(page))
2556                 skb->pfmemalloc = true;
2557 }
2558 
2559 /**
2560  * skb_frag_page - retrieve the page referred to by a paged fragment
2561  * @frag: the paged fragment
2562  *
2563  * Returns the &struct page associated with @frag.
2564  */
2565 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2566 {
2567         return frag->page.p;
2568 }
2569 
2570 /**
2571  * __skb_frag_ref - take an addition reference on a paged fragment.
2572  * @frag: the paged fragment
2573  *
2574  * Takes an additional reference on the paged fragment @frag.
2575  */
2576 static inline void __skb_frag_ref(skb_frag_t *frag)
2577 {
2578         get_page(skb_frag_page(frag));
2579 }
2580 
2581 /**
2582  * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2583  * @skb: the buffer
2584  * @f: the fragment offset.
2585  *
2586  * Takes an additional reference on the @f'th paged fragment of @skb.
2587  */
2588 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2589 {
2590         __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2591 }
2592 
2593 /**
2594  * __skb_frag_unref - release a reference on a paged fragment.
2595  * @frag: the paged fragment
2596  *
2597  * Releases a reference on the paged fragment @frag.
2598  */
2599 static inline void __skb_frag_unref(skb_frag_t *frag)
2600 {
2601         put_page(skb_frag_page(frag));
2602 }
2603 
2604 /**
2605  * skb_frag_unref - release a reference on a paged fragment of an skb.
2606  * @skb: the buffer
2607  * @f: the fragment offset
2608  *
2609  * Releases a reference on the @f'th paged fragment of @skb.
2610  */
2611 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2612 {
2613         __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2614 }
2615 
2616 /**
2617  * skb_frag_address - gets the address of the data contained in a paged fragment
2618  * @frag: the paged fragment buffer
2619  *
2620  * Returns the address of the data within @frag. The page must already
2621  * be mapped.
2622  */
2623 static inline void *skb_frag_address(const skb_frag_t *frag)
2624 {
2625         return page_address(skb_frag_page(frag)) + frag->page_offset;
2626 }
2627 
2628 /**
2629  * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2630  * @frag: the paged fragment buffer
2631  *
2632  * Returns the address of the data within @frag. Checks that the page
2633  * is mapped and returns %NULL otherwise.
2634  */
2635 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2636 {
2637         void *ptr = page_address(skb_frag_page(frag));
2638         if (unlikely(!ptr))
2639                 return NULL;
2640 
2641         return ptr + frag->page_offset;
2642 }
2643 
2644 /**
2645  * __skb_frag_set_page - sets the page contained in a paged fragment
2646  * @frag: the paged fragment
2647  * @page: the page to set
2648  *
2649  * Sets the fragment @frag to contain @page.
2650  */
2651 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2652 {
2653         frag->page.p = page;
2654 }
2655 
2656 /**
2657  * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2658  * @skb: the buffer
2659  * @f: the fragment offset
2660  * @page: the page to set
2661  *
2662  * Sets the @f'th fragment of @skb to contain @page.
2663  */
2664 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2665                                      struct page *page)
2666 {
2667         __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2668 }
2669 
2670 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2671 
2672 /**
2673  * skb_frag_dma_map - maps a paged fragment via the DMA API
2674  * @dev: the device to map the fragment to
2675  * @frag: the paged fragment to map
2676  * @offset: the offset within the fragment (starting at the
2677  *          fragment's own offset)
2678  * @size: the number of bytes to map
2679  * @dir: the direction of the mapping (%PCI_DMA_*)
2680  *
2681  * Maps the page associated with @frag to @device.
2682  */
2683 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2684                                           const skb_frag_t *frag,
2685                                           size_t offset, size_t size,
2686                                           enum dma_data_direction dir)
2687 {
2688         return dma_map_page(dev, skb_frag_page(frag),
2689                             frag->page_offset + offset, size, dir);
2690 }
2691 
2692 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2693                                         gfp_t gfp_mask)
2694 {
2695         return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2696 }
2697 
2698 
2699 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
2700                                                   gfp_t gfp_mask)
2701 {
2702         return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
2703 }
2704 
2705 
2706 /**
2707  *      skb_clone_writable - is the header of a clone writable
2708  *      @skb: buffer to check
2709  *      @len: length up to which to write
2710  *
2711  *      Returns true if modifying the header part of the cloned buffer
2712  *      does not requires the data to be copied.
2713  */
2714 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2715 {
2716         return !skb_header_cloned(skb) &&
2717                skb_headroom(skb) + len <= skb->hdr_len;
2718 }
2719 
2720 static inline int skb_try_make_writable(struct sk_buff *skb,
2721                                         unsigned int write_len)
2722 {
2723         return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
2724                pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2725 }
2726 
2727 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2728                             int cloned)
2729 {
2730         int delta = 0;
2731 
2732         if (headroom > skb_headroom(skb))
2733                 delta = headroom - skb_headroom(skb);
2734 
2735         if (delta || cloned)
2736                 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2737                                         GFP_ATOMIC);
2738         return 0;
2739 }
2740 
2741 /**
2742  *      skb_cow - copy header of skb when it is required
2743  *      @skb: buffer to cow
2744  *      @headroom: needed headroom
2745  *
2746  *      If the skb passed lacks sufficient headroom or its data part
2747  *      is shared, data is reallocated. If reallocation fails, an error
2748  *      is returned and original skb is not changed.
2749  *
2750  *      The result is skb with writable area skb->head...skb->tail
2751  *      and at least @headroom of space at head.
2752  */
2753 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2754 {
2755         return __skb_cow(skb, headroom, skb_cloned(skb));
2756 }
2757 
2758 /**
2759  *      skb_cow_head - skb_cow but only making the head writable
2760  *      @skb: buffer to cow
2761  *      @headroom: needed headroom
2762  *
2763  *      This function is identical to skb_cow except that we replace the
2764  *      skb_cloned check by skb_header_cloned.  It should be used when
2765  *      you only need to push on some header and do not need to modify
2766  *      the data.
2767  */
2768 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2769 {
2770         return __skb_cow(skb, headroom, skb_header_cloned(skb));
2771 }
2772 
2773 /**
2774  *      skb_padto       - pad an skbuff up to a minimal size
2775  *      @skb: buffer to pad
2776  *      @len: minimal length
2777  *
2778  *      Pads up a buffer to ensure the trailing bytes exist and are
2779  *      blanked. If the buffer already contains sufficient data it
2780  *      is untouched. Otherwise it is extended. Returns zero on
2781  *      success. The skb is freed on error.
2782  */
2783 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2784 {
2785         unsigned int size = skb->len;
2786         if (likely(size >= len))
2787                 return 0;
2788         return skb_pad(skb, len - size);
2789 }
2790 
2791 /**
2792  *      skb_put_padto - increase size and pad an skbuff up to a minimal size
2793  *      @skb: buffer to pad
2794  *      @len: minimal length
2795  *
2796  *      Pads up a buffer to ensure the trailing bytes exist and are
2797  *      blanked. If the buffer already contains sufficient data it
2798  *      is untouched. Otherwise it is extended. Returns zero on
2799  *      success. The skb is freed on error.
2800  */
2801 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
2802 {
2803         unsigned int size = skb->len;
2804 
2805         if (unlikely(size < len)) {
2806                 len -= size;
2807                 if (skb_pad(skb, len))
2808                         return -ENOMEM;
2809                 __skb_put(skb, len);
2810         }
2811         return 0;
2812 }
2813 
2814 static inline int skb_add_data(struct sk_buff *skb,
2815                                struct iov_iter *from, int copy)
2816 {
2817         const int off = skb->len;
2818 
2819         if (skb->ip_summed == CHECKSUM_NONE) {
2820                 __wsum csum = 0;
2821                 if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy,
2822                                                  &csum, from)) {
2823                         skb->csum = csum_block_add(skb->csum, csum, off);
2824                         return 0;
2825                 }
2826         } else if (copy_from_iter_full(skb_put(skb, copy), copy, from))
2827                 return 0;
2828 
2829         __skb_trim(skb, off);
2830         return -EFAULT;
2831 }
2832 
2833 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2834                                     const struct page *page, int off)
2835 {
2836         if (i) {
2837                 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2838 
2839                 return page == skb_frag_page(frag) &&
2840                        off == frag->page_offset + skb_frag_size(frag);
2841         }
2842         return false;
2843 }
2844 
2845 static inline int __skb_linearize(struct sk_buff *skb)
2846 {
2847         return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2848 }
2849 
2850 /**
2851  *      skb_linearize - convert paged skb to linear one
2852  *      @skb: buffer to linarize
2853  *
2854  *      If there is no free memory -ENOMEM is returned, otherwise zero
2855  *      is returned and the old skb data released.
2856  */
2857 static inline int skb_linearize(struct sk_buff *skb)
2858 {
2859         return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2860 }
2861 
2862 /**
2863  * skb_has_shared_frag - can any frag be overwritten
2864  * @skb: buffer to test
2865  *
2866  * Return true if the skb has at least one frag that might be modified
2867  * by an external entity (as in vmsplice()/sendfile())
2868  */
2869 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2870 {
2871         return skb_is_nonlinear(skb) &&
2872                skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2873 }
2874 
2875 /**
2876  *      skb_linearize_cow - make sure skb is linear and writable
2877  *      @skb: buffer to process
2878  *
2879  *      If there is no free memory -ENOMEM is returned, otherwise zero
2880  *      is returned and the old skb data released.
2881  */
2882 static inline int skb_linearize_cow(struct sk_buff *skb)
2883 {
2884         return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2885                __skb_linearize(skb) : 0;
2886 }
2887 
2888 static __always_inline void
2889 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
2890                      unsigned int off)
2891 {
2892         if (skb->ip_summed == CHECKSUM_COMPLETE)
2893                 skb->csum = csum_block_sub(skb->csum,
2894                                            csum_partial(start, len, 0), off);
2895         else if (skb->ip_summed == CHECKSUM_PARTIAL &&
2896                  skb_checksum_start_offset(skb) < 0)
2897                 skb->ip_summed = CHECKSUM_NONE;
2898 }
2899 
2900 /**
2901  *      skb_postpull_rcsum - update checksum for received skb after pull
2902  *      @skb: buffer to update
2903  *      @start: start of data before pull
2904  *      @len: length of data pulled
2905  *
2906  *      After doing a pull on a received packet, you need to call this to
2907  *      update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2908  *      CHECKSUM_NONE so that it can be recomputed from scratch.
2909  */
2910 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2911                                       const void *start, unsigned int len)
2912 {
2913         __skb_postpull_rcsum(skb, start, len, 0);
2914 }
2915 
2916 static __always_inline void
2917 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
2918                      unsigned int off)
2919 {
2920         if (skb->ip_summed == CHECKSUM_COMPLETE)
2921                 skb->csum = csum_block_add(skb->csum,
2922                                            csum_partial(start, len, 0), off);
2923 }
2924 
2925 /**
2926  *      skb_postpush_rcsum - update checksum for received skb after push
2927  *      @skb: buffer to update
2928  *      @start: start of data after push
2929  *      @len: length of data pushed
2930  *
2931  *      After doing a push on a received packet, you need to call this to
2932  *      update the CHECKSUM_COMPLETE checksum.
2933  */
2934 static inline void skb_postpush_rcsum(struct sk_buff *skb,
2935                                       const void *start, unsigned int len)
2936 {
2937         __skb_postpush_rcsum(skb, start, len, 0);
2938 }
2939 
2940 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2941 
2942 /**
2943  *      skb_push_rcsum - push skb and update receive checksum
2944  *      @skb: buffer to update
2945  *      @len: length of data pulled
2946  *
2947  *      This function performs an skb_push on the packet and updates
2948  *      the CHECKSUM_COMPLETE checksum.  It should be used on
2949  *      receive path processing instead of skb_push unless you know
2950  *      that the checksum difference is zero (e.g., a valid IP header)
2951  *      or you are setting ip_summed to CHECKSUM_NONE.
2952  */
2953 static inline unsigned char *skb_push_rcsum(struct sk_buff *skb,
2954                                             unsigned int len)
2955 {
2956         skb_push(skb, len);
2957         skb_postpush_rcsum(skb, skb->data, len);
2958         return skb->data;
2959 }
2960 
2961 /**
2962  *      pskb_trim_rcsum - trim received skb and update checksum
2963  *      @skb: buffer to trim
2964  *      @len: new length
2965  *
2966  *      This is exactly the same as pskb_trim except that it ensures the
2967  *      checksum of received packets are still valid after the operation.
2968  */
2969 
2970 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2971 {
2972         if (likely(len >= skb->len))
2973                 return 0;
2974         if (skb->ip_summed == CHECKSUM_COMPLETE)
2975                 skb->ip_summed = CHECKSUM_NONE;
2976         return __pskb_trim(skb, len);
2977 }
2978 
2979 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2980 {
2981         if (skb->ip_summed == CHECKSUM_COMPLETE)
2982                 skb->ip_summed = CHECKSUM_NONE;
2983         __skb_trim(skb, len);
2984         return 0;
2985 }
2986 
2987 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
2988 {
2989         if (skb->ip_summed == CHECKSUM_COMPLETE)
2990                 skb->ip_summed = CHECKSUM_NONE;
2991         return __skb_grow(skb, len);
2992 }
2993 
2994 #define skb_queue_walk(queue, skb) \
2995                 for (skb = (queue)->next;                                       \
2996                      skb != (struct sk_buff *)(queue);                          \
2997                      skb = skb->next)
2998 
2999 #define skb_queue_walk_safe(queue, skb, tmp)                                    \
3000                 for (skb = (queue)->next, tmp = skb->next;                      \
3001                      skb != (struct sk_buff *)(queue);                          \
3002                      skb = tmp, tmp = skb->next)
3003 
3004 #define skb_queue_walk_from(queue, skb)                                         \
3005                 for (; skb != (struct sk_buff *)(queue);                        \
3006                      skb = skb->next)
3007 
3008 #define skb_queue_walk_from_safe(queue, skb, tmp)                               \
3009                 for (tmp = skb->next;                                           \
3010                      skb != (struct sk_buff *)(queue);                          \
3011                      skb = tmp, tmp = skb->next)
3012 
3013 #define skb_queue_reverse_walk(queue, skb) \
3014                 for (skb = (queue)->prev;                                       \
3015                      skb != (struct sk_buff *)(queue);                          \
3016                      skb = skb->prev)
3017 
3018 #define skb_queue_reverse_walk_safe(queue, skb, tmp)                            \
3019                 for (skb = (queue)->prev, tmp = skb->prev;                      \
3020                      skb != (struct sk_buff *)(queue);                          \
3021                      skb = tmp, tmp = skb->prev)
3022 
3023 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp)                       \
3024                 for (tmp = skb->prev;                                           \
3025                      skb != (struct sk_buff *)(queue);                          \
3026                      skb = tmp, tmp = skb->prev)
3027 
3028 static inline bool skb_has_frag_list(const struct sk_buff *skb)
3029 {
3030         return skb_shinfo(skb)->frag_list != NULL;
3031 }
3032 
3033 static inline void skb_frag_list_init(struct sk_buff *skb)
3034 {
3035         skb_shinfo(skb)->frag_list = NULL;
3036 }
3037 
3038 #define skb_walk_frags(skb, iter)       \
3039         for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3040 
3041 
3042 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
3043                                 const struct sk_buff *skb);
3044 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
3045                                         void (*destructor)(struct sock *sk,
3046                                                            struct sk_buff *skb),
3047                                         int *peeked, int *off, int *err,
3048                                         struct sk_buff **last);
3049 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
3050                                     void (*destructor)(struct sock *sk,
3051                                                        struct sk_buff *skb),
3052                                     int *peeked, int *off, int *err);
3053 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
3054                                   int *err);
3055 unsigned int datagram_poll(struct file *file, struct socket *sock,
3056                            struct poll_table_struct *wait);
3057 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
3058                            struct iov_iter *to, int size);
3059 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
3060                                         struct msghdr *msg, int size)
3061 {
3062         return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
3063 }
3064 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
3065                                    struct msghdr *msg);
3066 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
3067                                  struct iov_iter *from, int len);
3068 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
3069 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
3070 void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
3071 static inline void skb_free_datagram_locked(struct sock *sk,
3072                                             struct sk_buff *skb)
3073 {
3074         __skb_free_datagram_locked(sk, skb, 0);
3075 }
3076 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
3077 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
3078 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
3079 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
3080                               int len, __wsum csum);
3081 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3082                     struct pipe_inode_info *pipe, unsigned int len,
3083                     unsigned int flags);
3084 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
3085 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
3086 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
3087                  int len, int hlen);
3088 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
3089 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
3090 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
3091 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
3092 bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu);
3093 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
3094 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
3095 int skb_ensure_writable(struct sk_buff *skb, int write_len);
3096 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
3097 int skb_vlan_pop(struct sk_buff *skb);
3098 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
3099 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
3100                              gfp_t gfp);
3101 
3102 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
3103 {
3104         return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3105 }
3106 
3107 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
3108 {
3109         return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3110 }
3111 
3112 struct skb_checksum_ops {
3113         __wsum (*update)(const void *mem, int len, __wsum wsum);
3114         __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
3115 };
3116 
3117 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3118                       __wsum csum, const struct skb_checksum_ops *ops);
3119 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
3120                     __wsum csum);
3121 
3122 static inline void * __must_check
3123 __skb_header_pointer(const struct sk_buff *skb, int offset,
3124                      int len, void *data, int hlen, void *buffer)
3125 {
3126         if (hlen - offset >= len)
3127                 return data + offset;
3128 
3129         if (!skb ||
3130             skb_copy_bits(skb, offset, buffer, len) < 0)
3131                 return NULL;
3132 
3133         return buffer;
3134 }
3135 
3136 static inline void * __must_check
3137 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
3138 {
3139         return __skb_header_pointer(skb, offset, len, skb->data,
3140                                     skb_headlen(skb), buffer);
3141 }
3142 
3143 /**
3144  *      skb_needs_linearize - check if we need to linearize a given skb
3145  *                            depending on the given device features.
3146  *      @skb: socket buffer to check
3147  *      @features: net device features
3148  *
3149  *      Returns true if either:
3150  *      1. skb has frag_list and the device doesn't support FRAGLIST, or
3151  *      2. skb is fragmented and the device does not support SG.
3152  */
3153 static inline bool skb_needs_linearize(struct sk_buff *skb,
3154                                        netdev_features_t features)
3155 {
3156         return skb_is_nonlinear(skb) &&
3157                ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3158                 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3159 }
3160 
3161 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3162                                              void *to,
3163                                              const unsigned int len)
3164 {
3165         memcpy(to, skb->data, len);
3166 }
3167 
3168 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3169                                                     const int offset, void *to,
3170                                                     const unsigned int len)
3171 {
3172         memcpy(to, skb->data + offset, len);
3173 }
3174 
3175 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3176                                            const void *from,
3177                                            const unsigned int len)
3178 {
3179         memcpy(skb->data, from, len);
3180 }
3181 
3182 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3183                                                   const int offset,
3184                                                   const void *from,
3185                                                   const unsigned int len)
3186 {
3187         memcpy(skb->data + offset, from, len);
3188 }
3189 
3190 void skb_init(void);
3191 
3192 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3193 {
3194         return skb->tstamp;
3195 }
3196 
3197 /**
3198  *      skb_get_timestamp - get timestamp from a skb
3199  *      @skb: skb to get stamp from
3200  *      @stamp: pointer to struct timeval to store stamp in
3201  *
3202  *      Timestamps are stored in the skb as offsets to a base timestamp.
3203  *      This function converts the offset back to a struct timeval and stores
3204  *      it in stamp.
3205  */
3206 static inline void skb_get_timestamp(const struct sk_buff *skb,
3207                                      struct timeval *stamp)
3208 {
3209         *stamp = ktime_to_timeval(skb->tstamp);
3210 }
3211 
3212 static inline void skb_get_timestampns(const struct sk_buff *skb,
3213                                        struct timespec *stamp)
3214 {
3215         *stamp = ktime_to_timespec(skb->tstamp);
3216 }
3217 
3218 static inline void __net_timestamp(struct sk_buff *skb)
3219 {
3220         skb->tstamp = ktime_get_real();
3221 }
3222 
3223 static inline ktime_t net_timedelta(ktime_t t)
3224 {
3225         return ktime_sub(ktime_get_real(), t);
3226 }
3227 
3228 static inline ktime_t net_invalid_timestamp(void)
3229 {
3230         return 0;
3231 }
3232 
3233 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3234 
3235 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3236 
3237 void skb_clone_tx_timestamp(struct sk_buff *skb);
3238 bool skb_defer_rx_timestamp(struct sk_buff *skb);
3239 
3240 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3241 
3242 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3243 {
3244 }
3245 
3246 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3247 {
3248         return false;
3249 }
3250 
3251 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3252 
3253 /**
3254  * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3255  *
3256  * PHY drivers may accept clones of transmitted packets for
3257  * timestamping via their phy_driver.txtstamp method. These drivers
3258  * must call this function to return the skb back to the stack with a
3259  * timestamp.
3260  *
3261  * @skb: clone of the the original outgoing packet
3262  * @hwtstamps: hardware time stamps
3263  *
3264  */
3265 void skb_complete_tx_timestamp(struct sk_buff *skb,
3266                                struct skb_shared_hwtstamps *hwtstamps);
3267 
3268 void __skb_tstamp_tx(struct sk_buff *orig_skb,
3269                      struct skb_shared_hwtstamps *hwtstamps,
3270                      struct sock *sk, int tstype);
3271 
3272 /**
3273  * skb_tstamp_tx - queue clone of skb with send time stamps
3274  * @orig_skb:   the original outgoing packet
3275  * @hwtstamps:  hardware time stamps, may be NULL if not available
3276  *
3277  * If the skb has a socket associated, then this function clones the
3278  * skb (thus sharing the actual data and optional structures), stores
3279  * the optional hardware time stamping information (if non NULL) or
3280  * generates a software time stamp (otherwise), then queues the clone
3281  * to the error queue of the socket.  Errors are silently ignored.
3282  */
3283 void skb_tstamp_tx(struct sk_buff *orig_skb,
3284                    struct skb_shared_hwtstamps *hwtstamps);
3285 
3286 static inline void sw_tx_timestamp(struct sk_buff *skb)
3287 {
3288         if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
3289             !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
3290                 skb_tstamp_tx(skb, NULL);
3291 }
3292 
3293 /**
3294  * skb_tx_timestamp() - Driver hook for transmit timestamping
3295  *
3296  * Ethernet MAC Drivers should call this function in their hard_xmit()
3297  * function immediately before giving the sk_buff to the MAC hardware.
3298  *
3299  * Specifically, one should make absolutely sure that this function is
3300  * called before TX completion of this packet can trigger.  Otherwise
3301  * the packet could potentially already be freed.
3302  *
3303  * @skb: A socket buffer.
3304  */
3305 static inline void skb_tx_timestamp(struct sk_buff *skb)
3306 {
3307         skb_clone_tx_timestamp(skb);
3308         sw_tx_timestamp(skb);
3309 }
3310 
3311 /**
3312  * skb_complete_wifi_ack - deliver skb with wifi status
3313  *
3314  * @skb: the original outgoing packet
3315  * @acked: ack status
3316  *
3317  */
3318 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3319 
3320 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3321 __sum16 __skb_checksum_complete(struct sk_buff *skb);
3322 
3323 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3324 {
3325         return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3326                 skb->csum_valid ||
3327                 (skb->ip_summed == CHECKSUM_PARTIAL &&
3328                  skb_checksum_start_offset(skb) >= 0));
3329 }
3330 
3331 /**
3332  *      skb_checksum_complete - Calculate checksum of an entire packet
3333  *      @skb: packet to process
3334  *
3335  *      This function calculates the checksum over the entire packet plus
3336  *      the value of skb->csum.  The latter can be used to supply the
3337  *      checksum of a pseudo header as used by TCP/UDP.  It returns the
3338  *      checksum.
3339  *
3340  *      For protocols that contain complete checksums such as ICMP/TCP/UDP,
3341  *      this function can be used to verify that checksum on received
3342  *      packets.  In that case the function should return zero if the
3343  *      checksum is correct.  In particular, this function will return zero
3344  *      if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3345  *      hardware has already verified the correctness of the checksum.
3346  */
3347 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3348 {
3349         return skb_csum_unnecessary(skb) ?
3350                0 : __skb_checksum_complete(skb);
3351 }
3352 
3353 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3354 {
3355         if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3356                 if (skb->csum_level == 0)
3357                         skb->ip_summed = CHECKSUM_NONE;
3358                 else
3359                         skb->csum_level--;
3360         }
3361 }
3362 
3363 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3364 {
3365         if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3366                 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3367                         skb->csum_level++;
3368         } else if (skb->ip_summed == CHECKSUM_NONE) {
3369                 skb->ip_summed = CHECKSUM_UNNECESSARY;
3370                 skb->csum_level = 0;
3371         }
3372 }
3373 
3374 static inline void __skb_mark_checksum_bad(struct sk_buff *skb)
3375 {
3376         /* Mark current checksum as bad (typically called from GRO
3377          * path). In the case that ip_summed is CHECKSUM_NONE
3378          * this must be the first checksum encountered in the packet.
3379          * When ip_summed is CHECKSUM_UNNECESSARY, this is the first
3380          * checksum after the last one validated. For UDP, a zero
3381          * checksum can not be marked as bad.
3382          */
3383 
3384         if (skb->ip_summed == CHECKSUM_NONE ||
3385             skb->ip_summed == CHECKSUM_UNNECESSARY)
3386                 skb->csum_bad = 1;
3387 }
3388 
3389 /* Check if we need to perform checksum complete validation.
3390  *
3391  * Returns true if checksum complete is needed, false otherwise
3392  * (either checksum is unnecessary or zero checksum is allowed).
3393  */
3394 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3395                                                   bool zero_okay,
3396                                                   __sum16 check)
3397 {
3398         if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3399                 skb->csum_valid = 1;
3400                 __skb_decr_checksum_unnecessary(skb);
3401                 return false;
3402         }
3403 
3404         return true;
3405 }
3406 
3407 /* For small packets <= CHECKSUM_BREAK peform checksum complete directly
3408  * in checksum_init.
3409  */
3410 #define CHECKSUM_BREAK 76
3411 
3412 /* Unset checksum-complete
3413  *
3414  * Unset checksum complete can be done when packet is being modified
3415  * (uncompressed for instance) and checksum-complete value is
3416  * invalidated.
3417  */
3418 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3419 {
3420         if (skb->ip_summed == CHECKSUM_COMPLETE)
3421                 skb->ip_summed = CHECKSUM_NONE;
3422 }
3423 
3424 /* Validate (init) checksum based on checksum complete.
3425  *
3426  * Return values:
3427  *   0: checksum is validated or try to in skb_checksum_complete. In the latter
3428  *      case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3429  *      checksum is stored in skb->csum for use in __skb_checksum_complete
3430  *   non-zero: value of invalid checksum
3431  *
3432  */
3433 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3434                                                        bool complete,
3435                                                        __wsum psum)
3436 {
3437         if (skb->ip_summed == CHECKSUM_COMPLETE) {
3438                 if (!csum_fold(csum_add(psum, skb->csum))) {
3439                         skb->csum_valid = 1;
3440                         return 0;
3441                 }
3442         } else if (skb->csum_bad) {
3443                 /* ip_summed == CHECKSUM_NONE in this case */
3444                 return (__force __sum16)1;
3445         }
3446 
3447         skb->csum = psum;
3448 
3449         if (complete || skb->len <= CHECKSUM_BREAK) {
3450                 __sum16 csum;
3451 
3452                 csum = __skb_checksum_complete(skb);
3453                 skb->csum_valid = !csum;
3454                 return csum;
3455         }
3456 
3457         return 0;
3458 }
3459 
3460 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3461 {
3462         return 0;
3463 }
3464 
3465 /* Perform checksum validate (init). Note that this is a macro since we only
3466  * want to calculate the pseudo header which is an input function if necessary.
3467  * First we try to validate without any computation (checksum unnecessary) and
3468  * then calculate based on checksum complete calling the function to compute
3469  * pseudo header.
3470  *
3471  * Return values:
3472  *   0: checksum is validated or try to in skb_checksum_complete
3473  *   non-zero: value of invalid checksum
3474  */
3475 #define __skb_checksum_validate(skb, proto, complete,                   \
3476                                 zero_okay, check, compute_pseudo)       \
3477 ({                                                                      \
3478         __sum16 __ret = 0;                                              \
3479         skb->csum_valid = 0;                                            \
3480         if (__skb_checksum_validate_needed(skb, zero_okay, check))      \
3481                 __ret = __skb_checksum_validate_complete(skb,           \
3482                                 complete, compute_pseudo(skb, proto));  \
3483         __ret;                                                          \
3484 })
3485 
3486 #define skb_checksum_init(skb, proto, compute_pseudo)                   \
3487         __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3488 
3489 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3490         __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3491 
3492 #define skb_checksum_validate(skb, proto, compute_pseudo)               \
3493         __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3494 
3495 #define skb_checksum_validate_zero_check(skb, proto, check,             \
3496                                          compute_pseudo)                \
3497         __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3498 
3499 #define skb_checksum_simple_validate(skb)                               \
3500         __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3501 
3502 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3503 {
3504         return (skb->ip_summed == CHECKSUM_NONE &&
3505                 skb->csum_valid && !skb->csum_bad);
3506 }
3507 
3508 static inline void __skb_checksum_convert(struct sk_buff *skb,
3509                                           __sum16 check, __wsum pseudo)
3510 {
3511         skb->csum = ~pseudo;
3512         skb->ip_summed = CHECKSUM_COMPLETE;
3513 }
3514 
3515 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo)     \
3516 do {                                                                    \
3517         if (__skb_checksum_convert_check(skb))                          \
3518                 __skb_checksum_convert(skb, check,                      \
3519                                        compute_pseudo(skb, proto));     \
3520 } while (0)
3521 
3522 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3523                                               u16 start, u16 offset)
3524 {
3525         skb->ip_summed = CHECKSUM_PARTIAL;
3526         skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3527         skb->csum_offset = offset - start;
3528 }
3529 
3530 /* Update skbuf and packet to reflect the remote checksum offload operation.
3531  * When called, ptr indicates the starting point for skb->csum when
3532  * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3533  * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3534  */
3535 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3536                                        int start, int offset, bool nopartial)
3537 {
3538         __wsum delta;
3539 
3540         if (!nopartial) {
3541                 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3542                 return;
3543         }
3544 
3545          if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3546                 __skb_checksum_complete(skb);
3547                 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3548         }
3549 
3550         delta = remcsum_adjust(ptr, skb->csum, start, offset);
3551 
3552         /* Adjust skb->csum since we changed the packet */
3553         skb->csum = csum_add(skb->csum, delta);
3554 }
3555 
3556 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3557 void nf_conntrack_destroy(struct nf_conntrack *nfct);
3558 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3559 {
3560         if (nfct && atomic_dec_and_test(&nfct->use))
3561                 nf_conntrack_destroy(nfct);
3562 }
3563 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3564 {
3565         if (nfct)
3566                 atomic_inc(&nfct->use);
3567 }
3568 #endif
3569 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3570 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
3571 {
3572         if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
3573                 kfree(nf_bridge);
3574 }
3575 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
3576 {
3577         if (nf_bridge)
3578                 atomic_inc(&nf_bridge->use);
3579 }
3580 #endif /* CONFIG_BRIDGE_NETFILTER */
3581 static inline void nf_reset(struct sk_buff *skb)
3582 {
3583 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3584         nf_conntrack_put(skb->nfct);
3585         skb->nfct = NULL;
3586 #endif
3587 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3588         nf_bridge_put(skb->nf_bridge);
3589         skb->nf_bridge = NULL;
3590 #endif
3591 }
3592 
3593 static inline void nf_reset_trace(struct sk_buff *skb)
3594 {
3595 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3596         skb->nf_trace = 0;
3597 #endif
3598 }
3599 
3600 /* Note: This doesn't put any conntrack and bridge info in dst. */
3601 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
3602                              bool copy)
3603 {
3604 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3605         dst->nfct = src->nfct;
3606         nf_conntrack_get(src->nfct);
3607         if (copy)
3608                 dst->nfctinfo = src->nfctinfo;
3609 #endif
3610 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3611         dst->nf_bridge  = src->nf_bridge;
3612         nf_bridge_get(src->nf_bridge);
3613 #endif
3614 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3615         if (copy)
3616                 dst->nf_trace = src->nf_trace;
3617 #endif
3618 }
3619 
3620 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
3621 {
3622 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3623         nf_conntrack_put(dst->nfct);
3624 #endif
3625 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3626         nf_bridge_put(dst->nf_bridge);
3627 #endif
3628         __nf_copy(dst, src, true);
3629 }
3630 
3631 #ifdef CONFIG_NETWORK_SECMARK
3632 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3633 {
3634         to->secmark = from->secmark;
3635 }
3636 
3637 static inline void skb_init_secmark(struct sk_buff *skb)
3638 {
3639         skb->secmark = 0;
3640 }
3641 #else
3642 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3643 { }
3644 
3645 static inline void skb_init_secmark(struct sk_buff *skb)
3646 { }
3647 #endif
3648 
3649 static inline bool skb_irq_freeable(const struct sk_buff *skb)
3650 {
3651         return !skb->destructor &&
3652 #if IS_ENABLED(CONFIG_XFRM)
3653                 !skb->sp &&
3654 #endif
3655 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3656                 !skb->nfct &&
3657 #endif
3658                 !skb->_skb_refdst &&
3659                 !skb_has_frag_list(skb);
3660 }
3661 
3662 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
3663 {
3664         skb->queue_mapping = queue_mapping;
3665 }
3666 
3667 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
3668 {
3669         return skb->queue_mapping;
3670 }
3671 
3672 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
3673 {
3674         to->queue_mapping = from->queue_mapping;
3675 }
3676 
3677 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
3678 {
3679         skb->queue_mapping = rx_queue + 1;
3680 }
3681 
3682 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
3683 {
3684         return skb->queue_mapping - 1;
3685 }
3686 
3687 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
3688 {
3689         return skb->queue_mapping != 0;
3690 }
3691 
3692 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
3693 {
3694 #ifdef CONFIG_XFRM
3695         return skb->sp;
3696 #else
3697         return NULL;
3698 #endif
3699 }
3700 
3701 /* Keeps track of mac header offset relative to skb->head.
3702  * It is useful for TSO of Tunneling protocol. e.g. GRE.
3703  * For non-tunnel skb it points to skb_mac_header() and for
3704  * tunnel skb it points to outer mac header.
3705  * Keeps track of level of encapsulation of network headers.
3706  */
3707 struct skb_gso_cb {
3708         union {
3709                 int     mac_offset;
3710                 int     data_offset;
3711         };
3712         int     encap_level;
3713         __wsum  csum;
3714         __u16   csum_start;
3715 };
3716 #define SKB_SGO_CB_OFFSET       32
3717 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
3718 
3719 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
3720 {
3721         return (skb_mac_header(inner_skb) - inner_skb->head) -
3722                 SKB_GSO_CB(inner_skb)->mac_offset;
3723 }
3724 
3725 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
3726 {
3727         int new_headroom, headroom;
3728         int ret;
3729 
3730         headroom = skb_headroom(skb);
3731         ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
3732         if (ret)
3733                 return ret;
3734 
3735         new_headroom = skb_headroom(skb);
3736         SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
3737         return 0;
3738 }
3739 
3740 static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
3741 {
3742         /* Do not update partial checksums if remote checksum is enabled. */
3743         if (skb->remcsum_offload)
3744                 return;
3745 
3746         SKB_GSO_CB(skb)->csum = res;
3747         SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
3748 }
3749 
3750 /* Compute the checksum for a gso segment. First compute the checksum value
3751  * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
3752  * then add in skb->csum (checksum from csum_start to end of packet).
3753  * skb->csum and csum_start are then updated to reflect the checksum of the
3754  * resultant packet starting from the transport header-- the resultant checksum
3755  * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
3756  * header.
3757  */
3758 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
3759 {
3760         unsigned char *csum_start = skb_transport_header(skb);
3761         int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
3762         __wsum partial = SKB_GSO_CB(skb)->csum;
3763 
3764         SKB_GSO_CB(skb)->csum = res;
3765         SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
3766 
3767         return csum_fold(csum_partial(csum_start, plen, partial));
3768 }
3769 
3770 static inline bool skb_is_gso(const struct sk_buff *skb)
3771 {
3772         return skb_shinfo(skb)->gso_size;
3773 }
3774 
3775 /* Note: Should be called only if skb_is_gso(skb) is true */
3776 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
3777 {
3778         return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
3779 }
3780 
3781 static inline void skb_gso_reset(struct sk_buff *skb)
3782 {
3783         skb_shinfo(skb)->gso_size = 0;
3784         skb_shinfo(skb)->gso_segs = 0;
3785         skb_shinfo(skb)->gso_type = 0;
3786 }
3787 
3788 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
3789 
3790 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
3791 {
3792         /* LRO sets gso_size but not gso_type, whereas if GSO is really
3793          * wanted then gso_type will be set. */
3794         const struct skb_shared_info *shinfo = skb_shinfo(skb);
3795 
3796         if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
3797             unlikely(shinfo->gso_type == 0)) {
3798                 __skb_warn_lro_forwarding(skb);
3799                 return true;
3800         }
3801         return false;
3802 }
3803 
3804 static inline void skb_forward_csum(struct sk_buff *skb)
3805 {
3806         /* Unfortunately we don't support this one.  Any brave souls? */
3807         if (skb->ip_summed == CHECKSUM_COMPLETE)
3808                 skb->ip_summed = CHECKSUM_NONE;
3809 }
3810 
3811 /**
3812  * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
3813  * @skb: skb to check
3814  *
3815  * fresh skbs have their ip_summed set to CHECKSUM_NONE.
3816  * Instead of forcing ip_summed to CHECKSUM_NONE, we can
3817  * use this helper, to document places where we make this assertion.
3818  */
3819 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
3820 {
3821 #ifdef DEBUG
3822         BUG_ON(skb->ip_summed != CHECKSUM_NONE);
3823 #endif
3824 }
3825 
3826 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
3827 
3828 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
3829 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
3830                                      unsigned int transport_len,
3831                                      __sum16(*skb_chkf)(struct sk_buff *skb));
3832 
3833 /**
3834  * skb_head_is_locked - Determine if the skb->head is locked down
3835  * @skb: skb to check
3836  *
3837  * The head on skbs build around a head frag can be removed if they are
3838  * not cloned.  This function returns true if the skb head is locked down
3839  * due to either being allocated via kmalloc, or by being a clone with
3840  * multiple references to the head.
3841  */
3842 static inline bool skb_head_is_locked(const struct sk_buff *skb)
3843 {
3844         return !skb->head_frag || skb_cloned(skb);
3845 }
3846 
3847 /**
3848  * skb_gso_network_seglen - Return length of individual segments of a gso packet
3849  *
3850  * @skb: GSO skb
3851  *
3852  * skb_gso_network_seglen is used to determine the real size of the
3853  * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
3854  *
3855  * The MAC/L2 header is not accounted for.
3856  */
3857 static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
3858 {
3859         unsigned int hdr_len = skb_transport_header(skb) -
3860                                skb_network_header(skb);
3861         return hdr_len + skb_gso_transport_seglen(skb);
3862 }
3863 
3864 /* Local Checksum Offload.
3865  * Compute outer checksum based on the assumption that the
3866  * inner checksum will be offloaded later.
3867  * See Documentation/networking/checksum-offloads.txt for
3868  * explanation of how this works.
3869  * Fill in outer checksum adjustment (e.g. with sum of outer
3870  * pseudo-header) before calling.
3871  * Also ensure that inner checksum is in linear data area.
3872  */
3873 static inline __wsum lco_csum(struct sk_buff *skb)
3874 {
3875         unsigned char *csum_start = skb_checksum_start(skb);
3876         unsigned char *l4_hdr = skb_transport_header(skb);
3877         __wsum partial;
3878 
3879         /* Start with complement of inner checksum adjustment */
3880         partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
3881                                                     skb->csum_offset));
3882 
3883         /* Add in checksum of our headers (incl. outer checksum
3884          * adjustment filled in by caller) and return result.
3885          */
3886         return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
3887 }
3888 
3889 #endif  /* __KERNEL__ */
3890 #endif  /* _LINUX_SKBUFF_H */
3891 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us