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TOMOYO Linux Cross Reference
Linux/include/linux/skbuff.h

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  1 /*
  2  *      Definitions for the 'struct sk_buff' memory handlers.
  3  *
  4  *      Authors:
  5  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  6  *              Florian La Roche, <rzsfl@rz.uni-sb.de>
  7  *
  8  *      This program is free software; you can redistribute it and/or
  9  *      modify it under the terms of the GNU General Public License
 10  *      as published by the Free Software Foundation; either version
 11  *      2 of the License, or (at your option) any later version.
 12  */
 13 
 14 #ifndef _LINUX_SKBUFF_H
 15 #define _LINUX_SKBUFF_H
 16 
 17 #include <linux/kernel.h>
 18 #include <linux/kmemcheck.h>
 19 #include <linux/compiler.h>
 20 #include <linux/time.h>
 21 #include <linux/bug.h>
 22 #include <linux/cache.h>
 23 #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 
 41 /* A. Checksumming of received packets by device.
 42  *
 43  * CHECKSUM_NONE:
 44  *
 45  *   Device failed to checksum this packet e.g. due to lack of capabilities.
 46  *   The packet contains full (though not verified) checksum in packet but
 47  *   not in skb->csum. Thus, skb->csum is undefined in this case.
 48  *
 49  * CHECKSUM_UNNECESSARY:
 50  *
 51  *   The hardware you're dealing with doesn't calculate the full checksum
 52  *   (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
 53  *   for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
 54  *   if their checksums are okay. skb->csum is still undefined in this case
 55  *   though. It is a bad option, but, unfortunately, nowadays most vendors do
 56  *   this. Apparently with the secret goal to sell you new devices, when you
 57  *   will add new protocol to your host, f.e. IPv6 8)
 58  *
 59  *   CHECKSUM_UNNECESSARY is applicable to following protocols:
 60  *     TCP: IPv6 and IPv4.
 61  *     UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
 62  *       zero UDP checksum for either IPv4 or IPv6, the networking stack
 63  *       may perform further validation in this case.
 64  *     GRE: only if the checksum is present in the header.
 65  *     SCTP: indicates the CRC in SCTP header has been validated.
 66  *
 67  *   skb->csum_level indicates the number of consecutive checksums found in
 68  *   the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
 69  *   For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
 70  *   and a device is able to verify the checksums for UDP (possibly zero),
 71  *   GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
 72  *   two. If the device were only able to verify the UDP checksum and not
 73  *   GRE, either because it doesn't support GRE checksum of because GRE
 74  *   checksum is bad, skb->csum_level would be set to zero (TCP checksum is
 75  *   not considered in this case).
 76  *
 77  * CHECKSUM_COMPLETE:
 78  *
 79  *   This is the most generic way. The device supplied checksum of the _whole_
 80  *   packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
 81  *   hardware doesn't need to parse L3/L4 headers to implement this.
 82  *
 83  *   Note: Even if device supports only some protocols, but is able to produce
 84  *   skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
 85  *
 86  * CHECKSUM_PARTIAL:
 87  *
 88  *   A checksum is set up to be offloaded to a device as described in the
 89  *   output description for CHECKSUM_PARTIAL. This may occur on a packet
 90  *   received directly from another Linux OS, e.g., a virtualized Linux kernel
 91  *   on the same host, or it may be set in the input path in GRO or remote
 92  *   checksum offload. For the purposes of checksum verification, the checksum
 93  *   referred to by skb->csum_start + skb->csum_offset and any preceding
 94  *   checksums in the packet are considered verified. Any checksums in the
 95  *   packet that are after the checksum being offloaded are not considered to
 96  *   be verified.
 97  *
 98  * B. Checksumming on output.
 99  *
100  * CHECKSUM_NONE:
101  *
102  *   The skb was already checksummed by the protocol, or a checksum is not
103  *   required.
104  *
105  * CHECKSUM_PARTIAL:
106  *
107  *   The device is required to checksum the packet as seen by hard_start_xmit()
108  *   from skb->csum_start up to the end, and to record/write the checksum at
109  *   offset skb->csum_start + skb->csum_offset.
110  *
111  *   The device must show its capabilities in dev->features, set up at device
112  *   setup time, e.g. netdev_features.h:
113  *
114  *      NETIF_F_HW_CSUM - It's a clever device, it's able to checksum everything.
115  *      NETIF_F_IP_CSUM - Device is dumb, it's able to checksum only TCP/UDP over
116  *                        IPv4. Sigh. Vendors like this way for an unknown reason.
117  *                        Though, see comment above about CHECKSUM_UNNECESSARY. 8)
118  *      NETIF_F_IPV6_CSUM - About as dumb as the last one but does IPv6 instead.
119  *      NETIF_F_...     - Well, you get the picture.
120  *
121  * CHECKSUM_UNNECESSARY:
122  *
123  *   Normally, the device will do per protocol specific checksumming. Protocol
124  *   implementations that do not want the NIC to perform the checksum
125  *   calculation should use this flag in their outgoing skbs.
126  *
127  *      NETIF_F_FCOE_CRC - This indicates that the device can do FCoE FC CRC
128  *                         offload. Correspondingly, the FCoE protocol driver
129  *                         stack should use CHECKSUM_UNNECESSARY.
130  *
131  * Any questions? No questions, good.           --ANK
132  */
133 
134 /* Don't change this without changing skb_csum_unnecessary! */
135 #define CHECKSUM_NONE           0
136 #define CHECKSUM_UNNECESSARY    1
137 #define CHECKSUM_COMPLETE       2
138 #define CHECKSUM_PARTIAL        3
139 
140 /* Maximum value in skb->csum_level */
141 #define SKB_MAX_CSUM_LEVEL      3
142 
143 #define SKB_DATA_ALIGN(X)       ALIGN(X, SMP_CACHE_BYTES)
144 #define SKB_WITH_OVERHEAD(X)    \
145         ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
146 #define SKB_MAX_ORDER(X, ORDER) \
147         SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
148 #define SKB_MAX_HEAD(X)         (SKB_MAX_ORDER((X), 0))
149 #define SKB_MAX_ALLOC           (SKB_MAX_ORDER(0, 2))
150 
151 /* return minimum truesize of one skb containing X bytes of data */
152 #define SKB_TRUESIZE(X) ((X) +                                          \
153                          SKB_DATA_ALIGN(sizeof(struct sk_buff)) +       \
154                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
155 
156 struct net_device;
157 struct scatterlist;
158 struct pipe_inode_info;
159 struct iov_iter;
160 struct napi_struct;
161 
162 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
163 struct nf_conntrack {
164         atomic_t use;
165 };
166 #endif
167 
168 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
169 struct nf_bridge_info {
170         atomic_t                use;
171         enum {
172                 BRNF_PROTO_UNCHANGED,
173                 BRNF_PROTO_8021Q,
174                 BRNF_PROTO_PPPOE
175         } orig_proto:8;
176         bool                    pkt_otherhost;
177         __u16                   frag_max_size;
178         unsigned int            mask;
179         struct net_device       *physindev;
180         union {
181                 struct net_device *physoutdev;
182                 char neigh_header[8];
183         };
184         union {
185                 __be32          ipv4_daddr;
186                 struct in6_addr ipv6_daddr;
187         };
188 };
189 #endif
190 
191 struct sk_buff_head {
192         /* These two members must be first. */
193         struct sk_buff  *next;
194         struct sk_buff  *prev;
195 
196         __u32           qlen;
197         spinlock_t      lock;
198 };
199 
200 struct sk_buff;
201 
202 /* To allow 64K frame to be packed as single skb without frag_list we
203  * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
204  * buffers which do not start on a page boundary.
205  *
206  * Since GRO uses frags we allocate at least 16 regardless of page
207  * size.
208  */
209 #if (65536/PAGE_SIZE + 1) < 16
210 #define MAX_SKB_FRAGS 16UL
211 #else
212 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
213 #endif
214 
215 typedef struct skb_frag_struct skb_frag_t;
216 
217 struct skb_frag_struct {
218         struct {
219                 struct page *p;
220         } page;
221 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
222         __u32 page_offset;
223         __u32 size;
224 #else
225         __u16 page_offset;
226         __u16 size;
227 #endif
228 };
229 
230 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
231 {
232         return frag->size;
233 }
234 
235 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
236 {
237         frag->size = size;
238 }
239 
240 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
241 {
242         frag->size += delta;
243 }
244 
245 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
246 {
247         frag->size -= delta;
248 }
249 
250 #define HAVE_HW_TIME_STAMP
251 
252 /**
253  * struct skb_shared_hwtstamps - hardware time stamps
254  * @hwtstamp:   hardware time stamp transformed into duration
255  *              since arbitrary point in time
256  *
257  * Software time stamps generated by ktime_get_real() are stored in
258  * skb->tstamp.
259  *
260  * hwtstamps can only be compared against other hwtstamps from
261  * the same device.
262  *
263  * This structure is attached to packets as part of the
264  * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
265  */
266 struct skb_shared_hwtstamps {
267         ktime_t hwtstamp;
268 };
269 
270 /* Definitions for tx_flags in struct skb_shared_info */
271 enum {
272         /* generate hardware time stamp */
273         SKBTX_HW_TSTAMP = 1 << 0,
274 
275         /* generate software time stamp when queueing packet to NIC */
276         SKBTX_SW_TSTAMP = 1 << 1,
277 
278         /* device driver is going to provide hardware time stamp */
279         SKBTX_IN_PROGRESS = 1 << 2,
280 
281         /* device driver supports TX zero-copy buffers */
282         SKBTX_DEV_ZEROCOPY = 1 << 3,
283 
284         /* generate wifi status information (where possible) */
285         SKBTX_WIFI_STATUS = 1 << 4,
286 
287         /* This indicates at least one fragment might be overwritten
288          * (as in vmsplice(), sendfile() ...)
289          * If we need to compute a TX checksum, we'll need to copy
290          * all frags to avoid possible bad checksum
291          */
292         SKBTX_SHARED_FRAG = 1 << 5,
293 
294         /* generate software time stamp when entering packet scheduling */
295         SKBTX_SCHED_TSTAMP = 1 << 6,
296 
297         /* generate software timestamp on peer data acknowledgment */
298         SKBTX_ACK_TSTAMP = 1 << 7,
299 };
300 
301 #define SKBTX_ANY_SW_TSTAMP     (SKBTX_SW_TSTAMP    | \
302                                  SKBTX_SCHED_TSTAMP | \
303                                  SKBTX_ACK_TSTAMP)
304 #define SKBTX_ANY_TSTAMP        (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
305 
306 /*
307  * The callback notifies userspace to release buffers when skb DMA is done in
308  * lower device, the skb last reference should be 0 when calling this.
309  * The zerocopy_success argument is true if zero copy transmit occurred,
310  * false on data copy or out of memory error caused by data copy attempt.
311  * The ctx field is used to track device context.
312  * The desc field is used to track userspace buffer index.
313  */
314 struct ubuf_info {
315         void (*callback)(struct ubuf_info *, bool zerocopy_success);
316         void *ctx;
317         unsigned long desc;
318 };
319 
320 /* This data is invariant across clones and lives at
321  * the end of the header data, ie. at skb->end.
322  */
323 struct skb_shared_info {
324         unsigned char   nr_frags;
325         __u8            tx_flags;
326         unsigned short  gso_size;
327         /* Warning: this field is not always filled in (UFO)! */
328         unsigned short  gso_segs;
329         unsigned short  gso_type;
330         struct sk_buff  *frag_list;
331         struct skb_shared_hwtstamps hwtstamps;
332         u32             tskey;
333         __be32          ip6_frag_id;
334 
335         /*
336          * Warning : all fields before dataref are cleared in __alloc_skb()
337          */
338         atomic_t        dataref;
339 
340         /* Intermediate layers must ensure that destructor_arg
341          * remains valid until skb destructor */
342         void *          destructor_arg;
343 
344         /* must be last field, see pskb_expand_head() */
345         skb_frag_t      frags[MAX_SKB_FRAGS];
346 };
347 
348 /* We divide dataref into two halves.  The higher 16 bits hold references
349  * to the payload part of skb->data.  The lower 16 bits hold references to
350  * the entire skb->data.  A clone of a headerless skb holds the length of
351  * the header in skb->hdr_len.
352  *
353  * All users must obey the rule that the skb->data reference count must be
354  * greater than or equal to the payload reference count.
355  *
356  * Holding a reference to the payload part means that the user does not
357  * care about modifications to the header part of skb->data.
358  */
359 #define SKB_DATAREF_SHIFT 16
360 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
361 
362 
363 enum {
364         SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
365         SKB_FCLONE_ORIG,        /* orig skb (from fclone_cache) */
366         SKB_FCLONE_CLONE,       /* companion fclone skb (from fclone_cache) */
367 };
368 
369 enum {
370         SKB_GSO_TCPV4 = 1 << 0,
371         SKB_GSO_UDP = 1 << 1,
372 
373         /* This indicates the skb is from an untrusted source. */
374         SKB_GSO_DODGY = 1 << 2,
375 
376         /* This indicates the tcp segment has CWR set. */
377         SKB_GSO_TCP_ECN = 1 << 3,
378 
379         SKB_GSO_TCPV6 = 1 << 4,
380 
381         SKB_GSO_FCOE = 1 << 5,
382 
383         SKB_GSO_GRE = 1 << 6,
384 
385         SKB_GSO_GRE_CSUM = 1 << 7,
386 
387         SKB_GSO_IPIP = 1 << 8,
388 
389         SKB_GSO_SIT = 1 << 9,
390 
391         SKB_GSO_UDP_TUNNEL = 1 << 10,
392 
393         SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
394 
395         SKB_GSO_TUNNEL_REMCSUM = 1 << 12,
396 };
397 
398 #if BITS_PER_LONG > 32
399 #define NET_SKBUFF_DATA_USES_OFFSET 1
400 #endif
401 
402 #ifdef NET_SKBUFF_DATA_USES_OFFSET
403 typedef unsigned int sk_buff_data_t;
404 #else
405 typedef unsigned char *sk_buff_data_t;
406 #endif
407 
408 /**
409  * struct skb_mstamp - multi resolution time stamps
410  * @stamp_us: timestamp in us resolution
411  * @stamp_jiffies: timestamp in jiffies
412  */
413 struct skb_mstamp {
414         union {
415                 u64             v64;
416                 struct {
417                         u32     stamp_us;
418                         u32     stamp_jiffies;
419                 };
420         };
421 };
422 
423 /**
424  * skb_mstamp_get - get current timestamp
425  * @cl: place to store timestamps
426  */
427 static inline void skb_mstamp_get(struct skb_mstamp *cl)
428 {
429         u64 val = local_clock();
430 
431         do_div(val, NSEC_PER_USEC);
432         cl->stamp_us = (u32)val;
433         cl->stamp_jiffies = (u32)jiffies;
434 }
435 
436 /**
437  * skb_mstamp_delta - compute the difference in usec between two skb_mstamp
438  * @t1: pointer to newest sample
439  * @t0: pointer to oldest sample
440  */
441 static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
442                                       const struct skb_mstamp *t0)
443 {
444         s32 delta_us = t1->stamp_us - t0->stamp_us;
445         u32 delta_jiffies = t1->stamp_jiffies - t0->stamp_jiffies;
446 
447         /* If delta_us is negative, this might be because interval is too big,
448          * or local_clock() drift is too big : fallback using jiffies.
449          */
450         if (delta_us <= 0 ||
451             delta_jiffies >= (INT_MAX / (USEC_PER_SEC / HZ)))
452 
453                 delta_us = jiffies_to_usecs(delta_jiffies);
454 
455         return delta_us;
456 }
457 
458 
459 /** 
460  *      struct sk_buff - socket buffer
461  *      @next: Next buffer in list
462  *      @prev: Previous buffer in list
463  *      @tstamp: Time we arrived/left
464  *      @rbnode: RB tree node, alternative to next/prev for netem/tcp
465  *      @sk: Socket we are owned by
466  *      @dev: Device we arrived on/are leaving by
467  *      @cb: Control buffer. Free for use by every layer. Put private vars here
468  *      @_skb_refdst: destination entry (with norefcount bit)
469  *      @sp: the security path, used for xfrm
470  *      @len: Length of actual data
471  *      @data_len: Data length
472  *      @mac_len: Length of link layer header
473  *      @hdr_len: writable header length of cloned skb
474  *      @csum: Checksum (must include start/offset pair)
475  *      @csum_start: Offset from skb->head where checksumming should start
476  *      @csum_offset: Offset from csum_start where checksum should be stored
477  *      @priority: Packet queueing priority
478  *      @ignore_df: allow local fragmentation
479  *      @cloned: Head may be cloned (check refcnt to be sure)
480  *      @ip_summed: Driver fed us an IP checksum
481  *      @nohdr: Payload reference only, must not modify header
482  *      @nfctinfo: Relationship of this skb to the connection
483  *      @pkt_type: Packet class
484  *      @fclone: skbuff clone status
485  *      @ipvs_property: skbuff is owned by ipvs
486  *      @peeked: this packet has been seen already, so stats have been
487  *              done for it, don't do them again
488  *      @nf_trace: netfilter packet trace flag
489  *      @protocol: Packet protocol from driver
490  *      @destructor: Destruct function
491  *      @nfct: Associated connection, if any
492  *      @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
493  *      @skb_iif: ifindex of device we arrived on
494  *      @tc_index: Traffic control index
495  *      @tc_verd: traffic control verdict
496  *      @hash: the packet hash
497  *      @queue_mapping: Queue mapping for multiqueue devices
498  *      @xmit_more: More SKBs are pending for this queue
499  *      @ndisc_nodetype: router type (from link layer)
500  *      @ooo_okay: allow the mapping of a socket to a queue to be changed
501  *      @l4_hash: indicate hash is a canonical 4-tuple hash over transport
502  *              ports.
503  *      @sw_hash: indicates hash was computed in software stack
504  *      @wifi_acked_valid: wifi_acked was set
505  *      @wifi_acked: whether frame was acked on wifi or not
506  *      @no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
507   *     @napi_id: id of the NAPI struct this skb came from
508  *      @secmark: security marking
509  *      @mark: Generic packet mark
510  *      @vlan_proto: vlan encapsulation protocol
511  *      @vlan_tci: vlan tag control information
512  *      @inner_protocol: Protocol (encapsulation)
513  *      @inner_transport_header: Inner transport layer header (encapsulation)
514  *      @inner_network_header: Network layer header (encapsulation)
515  *      @inner_mac_header: Link layer header (encapsulation)
516  *      @transport_header: Transport layer header
517  *      @network_header: Network layer header
518  *      @mac_header: Link layer header
519  *      @tail: Tail pointer
520  *      @end: End pointer
521  *      @head: Head of buffer
522  *      @data: Data head pointer
523  *      @truesize: Buffer size
524  *      @users: User count - see {datagram,tcp}.c
525  */
526 
527 struct sk_buff {
528         union {
529                 struct {
530                         /* These two members must be first. */
531                         struct sk_buff          *next;
532                         struct sk_buff          *prev;
533 
534                         union {
535                                 ktime_t         tstamp;
536                                 struct skb_mstamp skb_mstamp;
537                         };
538                 };
539                 struct rb_node  rbnode; /* used in netem & tcp stack */
540         };
541         struct sock             *sk;
542         struct net_device       *dev;
543 
544         /*
545          * This is the control buffer. It is free to use for every
546          * layer. Please put your private variables there. If you
547          * want to keep them across layers you have to do a skb_clone()
548          * first. This is owned by whoever has the skb queued ATM.
549          */
550         char                    cb[48] __aligned(8);
551 
552         unsigned long           _skb_refdst;
553         void                    (*destructor)(struct sk_buff *skb);
554 #ifdef CONFIG_XFRM
555         struct  sec_path        *sp;
556 #endif
557 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
558         struct nf_conntrack     *nfct;
559 #endif
560 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
561         struct nf_bridge_info   *nf_bridge;
562 #endif
563         unsigned int            len,
564                                 data_len;
565         __u16                   mac_len,
566                                 hdr_len;
567 
568         /* Following fields are _not_ copied in __copy_skb_header()
569          * Note that queue_mapping is here mostly to fill a hole.
570          */
571         kmemcheck_bitfield_begin(flags1);
572         __u16                   queue_mapping;
573         __u8                    cloned:1,
574                                 nohdr:1,
575                                 fclone:2,
576                                 peeked:1,
577                                 head_frag:1,
578                                 xmit_more:1;
579         /* one bit hole */
580         kmemcheck_bitfield_end(flags1);
581 
582         /* fields enclosed in headers_start/headers_end are copied
583          * using a single memcpy() in __copy_skb_header()
584          */
585         /* private: */
586         __u32                   headers_start[0];
587         /* public: */
588 
589 /* if you move pkt_type around you also must adapt those constants */
590 #ifdef __BIG_ENDIAN_BITFIELD
591 #define PKT_TYPE_MAX    (7 << 5)
592 #else
593 #define PKT_TYPE_MAX    7
594 #endif
595 #define PKT_TYPE_OFFSET()       offsetof(struct sk_buff, __pkt_type_offset)
596 
597         __u8                    __pkt_type_offset[0];
598         __u8                    pkt_type:3;
599         __u8                    pfmemalloc:1;
600         __u8                    ignore_df:1;
601         __u8                    nfctinfo:3;
602 
603         __u8                    nf_trace:1;
604         __u8                    ip_summed:2;
605         __u8                    ooo_okay:1;
606         __u8                    l4_hash:1;
607         __u8                    sw_hash:1;
608         __u8                    wifi_acked_valid:1;
609         __u8                    wifi_acked:1;
610 
611         __u8                    no_fcs:1;
612         /* Indicates the inner headers are valid in the skbuff. */
613         __u8                    encapsulation:1;
614         __u8                    encap_hdr_csum:1;
615         __u8                    csum_valid:1;
616         __u8                    csum_complete_sw:1;
617         __u8                    csum_level:2;
618         __u8                    csum_bad:1;
619 
620 #ifdef CONFIG_IPV6_NDISC_NODETYPE
621         __u8                    ndisc_nodetype:2;
622 #endif
623         __u8                    ipvs_property:1;
624         __u8                    inner_protocol_type:1;
625         __u8                    remcsum_offload:1;
626         /* 3 or 5 bit hole */
627 
628 #ifdef CONFIG_NET_SCHED
629         __u16                   tc_index;       /* traffic control index */
630 #ifdef CONFIG_NET_CLS_ACT
631         __u16                   tc_verd;        /* traffic control verdict */
632 #endif
633 #endif
634 
635         union {
636                 __wsum          csum;
637                 struct {
638                         __u16   csum_start;
639                         __u16   csum_offset;
640                 };
641         };
642         __u32                   priority;
643         int                     skb_iif;
644         __u32                   hash;
645         __be16                  vlan_proto;
646         __u16                   vlan_tci;
647 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
648         union {
649                 unsigned int    napi_id;
650                 unsigned int    sender_cpu;
651         };
652 #endif
653 #ifdef CONFIG_NETWORK_SECMARK
654         __u32                   secmark;
655 #endif
656         union {
657                 __u32           mark;
658                 __u32           reserved_tailroom;
659         };
660 
661         union {
662                 __be16          inner_protocol;
663                 __u8            inner_ipproto;
664         };
665 
666         __u16                   inner_transport_header;
667         __u16                   inner_network_header;
668         __u16                   inner_mac_header;
669 
670         __be16                  protocol;
671         __u16                   transport_header;
672         __u16                   network_header;
673         __u16                   mac_header;
674 
675         /* private: */
676         __u32                   headers_end[0];
677         /* public: */
678 
679         /* These elements must be at the end, see alloc_skb() for details.  */
680         sk_buff_data_t          tail;
681         sk_buff_data_t          end;
682         unsigned char           *head,
683                                 *data;
684         unsigned int            truesize;
685         atomic_t                users;
686 };
687 
688 #ifdef __KERNEL__
689 /*
690  *      Handling routines are only of interest to the kernel
691  */
692 #include <linux/slab.h>
693 
694 
695 #define SKB_ALLOC_FCLONE        0x01
696 #define SKB_ALLOC_RX            0x02
697 #define SKB_ALLOC_NAPI          0x04
698 
699 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
700 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
701 {
702         return unlikely(skb->pfmemalloc);
703 }
704 
705 /*
706  * skb might have a dst pointer attached, refcounted or not.
707  * _skb_refdst low order bit is set if refcount was _not_ taken
708  */
709 #define SKB_DST_NOREF   1UL
710 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
711 
712 /**
713  * skb_dst - returns skb dst_entry
714  * @skb: buffer
715  *
716  * Returns skb dst_entry, regardless of reference taken or not.
717  */
718 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
719 {
720         /* If refdst was not refcounted, check we still are in a 
721          * rcu_read_lock section
722          */
723         WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
724                 !rcu_read_lock_held() &&
725                 !rcu_read_lock_bh_held());
726         return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
727 }
728 
729 /**
730  * skb_dst_set - sets skb dst
731  * @skb: buffer
732  * @dst: dst entry
733  *
734  * Sets skb dst, assuming a reference was taken on dst and should
735  * be released by skb_dst_drop()
736  */
737 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
738 {
739         skb->_skb_refdst = (unsigned long)dst;
740 }
741 
742 /**
743  * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
744  * @skb: buffer
745  * @dst: dst entry
746  *
747  * Sets skb dst, assuming a reference was not taken on dst.
748  * If dst entry is cached, we do not take reference and dst_release
749  * will be avoided by refdst_drop. If dst entry is not cached, we take
750  * reference, so that last dst_release can destroy the dst immediately.
751  */
752 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
753 {
754         WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
755         skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
756 }
757 
758 /**
759  * skb_dst_is_noref - Test if skb dst isn't refcounted
760  * @skb: buffer
761  */
762 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
763 {
764         return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
765 }
766 
767 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
768 {
769         return (struct rtable *)skb_dst(skb);
770 }
771 
772 void kfree_skb(struct sk_buff *skb);
773 void kfree_skb_list(struct sk_buff *segs);
774 void skb_tx_error(struct sk_buff *skb);
775 void consume_skb(struct sk_buff *skb);
776 void  __kfree_skb(struct sk_buff *skb);
777 extern struct kmem_cache *skbuff_head_cache;
778 
779 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
780 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
781                       bool *fragstolen, int *delta_truesize);
782 
783 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
784                             int node);
785 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
786 struct sk_buff *build_skb(void *data, unsigned int frag_size);
787 static inline struct sk_buff *alloc_skb(unsigned int size,
788                                         gfp_t priority)
789 {
790         return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
791 }
792 
793 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
794                                      unsigned long data_len,
795                                      int max_page_order,
796                                      int *errcode,
797                                      gfp_t gfp_mask);
798 
799 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
800 struct sk_buff_fclones {
801         struct sk_buff  skb1;
802 
803         struct sk_buff  skb2;
804 
805         atomic_t        fclone_ref;
806 };
807 
808 /**
809  *      skb_fclone_busy - check if fclone is busy
810  *      @skb: buffer
811  *
812  * Returns true is skb is a fast clone, and its clone is not freed.
813  * Some drivers call skb_orphan() in their ndo_start_xmit(),
814  * so we also check that this didnt happen.
815  */
816 static inline bool skb_fclone_busy(const struct sock *sk,
817                                    const struct sk_buff *skb)
818 {
819         const struct sk_buff_fclones *fclones;
820 
821         fclones = container_of(skb, struct sk_buff_fclones, skb1);
822 
823         return skb->fclone == SKB_FCLONE_ORIG &&
824                atomic_read(&fclones->fclone_ref) > 1 &&
825                fclones->skb2.sk == sk;
826 }
827 
828 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
829                                                gfp_t priority)
830 {
831         return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
832 }
833 
834 struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
835 static inline struct sk_buff *alloc_skb_head(gfp_t priority)
836 {
837         return __alloc_skb_head(priority, -1);
838 }
839 
840 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
841 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
842 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
843 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
844 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
845                                    gfp_t gfp_mask, bool fclone);
846 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
847                                           gfp_t gfp_mask)
848 {
849         return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
850 }
851 
852 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
853 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
854                                      unsigned int headroom);
855 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
856                                 int newtailroom, gfp_t priority);
857 int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
858                         int offset, int len);
859 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
860                  int len);
861 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
862 int skb_pad(struct sk_buff *skb, int pad);
863 #define dev_kfree_skb(a)        consume_skb(a)
864 
865 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
866                             int getfrag(void *from, char *to, int offset,
867                                         int len, int odd, struct sk_buff *skb),
868                             void *from, int length);
869 
870 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
871                          int offset, size_t size);
872 
873 struct skb_seq_state {
874         __u32           lower_offset;
875         __u32           upper_offset;
876         __u32           frag_idx;
877         __u32           stepped_offset;
878         struct sk_buff  *root_skb;
879         struct sk_buff  *cur_skb;
880         __u8            *frag_data;
881 };
882 
883 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
884                           unsigned int to, struct skb_seq_state *st);
885 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
886                           struct skb_seq_state *st);
887 void skb_abort_seq_read(struct skb_seq_state *st);
888 
889 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
890                            unsigned int to, struct ts_config *config);
891 
892 /*
893  * Packet hash types specify the type of hash in skb_set_hash.
894  *
895  * Hash types refer to the protocol layer addresses which are used to
896  * construct a packet's hash. The hashes are used to differentiate or identify
897  * flows of the protocol layer for the hash type. Hash types are either
898  * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
899  *
900  * Properties of hashes:
901  *
902  * 1) Two packets in different flows have different hash values
903  * 2) Two packets in the same flow should have the same hash value
904  *
905  * A hash at a higher layer is considered to be more specific. A driver should
906  * set the most specific hash possible.
907  *
908  * A driver cannot indicate a more specific hash than the layer at which a hash
909  * was computed. For instance an L3 hash cannot be set as an L4 hash.
910  *
911  * A driver may indicate a hash level which is less specific than the
912  * actual layer the hash was computed on. For instance, a hash computed
913  * at L4 may be considered an L3 hash. This should only be done if the
914  * driver can't unambiguously determine that the HW computed the hash at
915  * the higher layer. Note that the "should" in the second property above
916  * permits this.
917  */
918 enum pkt_hash_types {
919         PKT_HASH_TYPE_NONE,     /* Undefined type */
920         PKT_HASH_TYPE_L2,       /* Input: src_MAC, dest_MAC */
921         PKT_HASH_TYPE_L3,       /* Input: src_IP, dst_IP */
922         PKT_HASH_TYPE_L4,       /* Input: src_IP, dst_IP, src_port, dst_port */
923 };
924 
925 static inline void
926 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
927 {
928         skb->l4_hash = (type == PKT_HASH_TYPE_L4);
929         skb->sw_hash = 0;
930         skb->hash = hash;
931 }
932 
933 static inline __u32 skb_get_hash(struct sk_buff *skb)
934 {
935         if (!skb->l4_hash && !skb->sw_hash)
936                 __skb_get_hash(skb);
937 
938         return skb->hash;
939 }
940 
941 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
942 
943 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
944 {
945         return skb->hash;
946 }
947 
948 static inline void skb_clear_hash(struct sk_buff *skb)
949 {
950         skb->hash = 0;
951         skb->sw_hash = 0;
952         skb->l4_hash = 0;
953 }
954 
955 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
956 {
957         if (!skb->l4_hash)
958                 skb_clear_hash(skb);
959 }
960 
961 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
962 {
963         to->hash = from->hash;
964         to->sw_hash = from->sw_hash;
965         to->l4_hash = from->l4_hash;
966 };
967 
968 static inline void skb_sender_cpu_clear(struct sk_buff *skb)
969 {
970 #ifdef CONFIG_XPS
971         skb->sender_cpu = 0;
972 #endif
973 }
974 
975 #ifdef NET_SKBUFF_DATA_USES_OFFSET
976 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
977 {
978         return skb->head + skb->end;
979 }
980 
981 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
982 {
983         return skb->end;
984 }
985 #else
986 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
987 {
988         return skb->end;
989 }
990 
991 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
992 {
993         return skb->end - skb->head;
994 }
995 #endif
996 
997 /* Internal */
998 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
999 
1000 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1001 {
1002         return &skb_shinfo(skb)->hwtstamps;
1003 }
1004 
1005 /**
1006  *      skb_queue_empty - check if a queue is empty
1007  *      @list: queue head
1008  *
1009  *      Returns true if the queue is empty, false otherwise.
1010  */
1011 static inline int skb_queue_empty(const struct sk_buff_head *list)
1012 {
1013         return list->next == (const struct sk_buff *) list;
1014 }
1015 
1016 /**
1017  *      skb_queue_is_last - check if skb is the last entry in the queue
1018  *      @list: queue head
1019  *      @skb: buffer
1020  *
1021  *      Returns true if @skb is the last buffer on the list.
1022  */
1023 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1024                                      const struct sk_buff *skb)
1025 {
1026         return skb->next == (const struct sk_buff *) list;
1027 }
1028 
1029 /**
1030  *      skb_queue_is_first - check if skb is the first entry in the queue
1031  *      @list: queue head
1032  *      @skb: buffer
1033  *
1034  *      Returns true if @skb is the first buffer on the list.
1035  */
1036 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1037                                       const struct sk_buff *skb)
1038 {
1039         return skb->prev == (const struct sk_buff *) list;
1040 }
1041 
1042 /**
1043  *      skb_queue_next - return the next packet in the queue
1044  *      @list: queue head
1045  *      @skb: current buffer
1046  *
1047  *      Return the next packet in @list after @skb.  It is only valid to
1048  *      call this if skb_queue_is_last() evaluates to false.
1049  */
1050 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1051                                              const struct sk_buff *skb)
1052 {
1053         /* This BUG_ON may seem severe, but if we just return then we
1054          * are going to dereference garbage.
1055          */
1056         BUG_ON(skb_queue_is_last(list, skb));
1057         return skb->next;
1058 }
1059 
1060 /**
1061  *      skb_queue_prev - return the prev packet in the queue
1062  *      @list: queue head
1063  *      @skb: current buffer
1064  *
1065  *      Return the prev packet in @list before @skb.  It is only valid to
1066  *      call this if skb_queue_is_first() evaluates to false.
1067  */
1068 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1069                                              const struct sk_buff *skb)
1070 {
1071         /* This BUG_ON may seem severe, but if we just return then we
1072          * are going to dereference garbage.
1073          */
1074         BUG_ON(skb_queue_is_first(list, skb));
1075         return skb->prev;
1076 }
1077 
1078 /**
1079  *      skb_get - reference buffer
1080  *      @skb: buffer to reference
1081  *
1082  *      Makes another reference to a socket buffer and returns a pointer
1083  *      to the buffer.
1084  */
1085 static inline struct sk_buff *skb_get(struct sk_buff *skb)
1086 {
1087         atomic_inc(&skb->users);
1088         return skb;
1089 }
1090 
1091 /*
1092  * If users == 1, we are the only owner and are can avoid redundant
1093  * atomic change.
1094  */
1095 
1096 /**
1097  *      skb_cloned - is the buffer a clone
1098  *      @skb: buffer to check
1099  *
1100  *      Returns true if the buffer was generated with skb_clone() and is
1101  *      one of multiple shared copies of the buffer. Cloned buffers are
1102  *      shared data so must not be written to under normal circumstances.
1103  */
1104 static inline int skb_cloned(const struct sk_buff *skb)
1105 {
1106         return skb->cloned &&
1107                (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1108 }
1109 
1110 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1111 {
1112         might_sleep_if(pri & __GFP_WAIT);
1113 
1114         if (skb_cloned(skb))
1115                 return pskb_expand_head(skb, 0, 0, pri);
1116 
1117         return 0;
1118 }
1119 
1120 /**
1121  *      skb_header_cloned - is the header a clone
1122  *      @skb: buffer to check
1123  *
1124  *      Returns true if modifying the header part of the buffer requires
1125  *      the data to be copied.
1126  */
1127 static inline int skb_header_cloned(const struct sk_buff *skb)
1128 {
1129         int dataref;
1130 
1131         if (!skb->cloned)
1132                 return 0;
1133 
1134         dataref = atomic_read(&skb_shinfo(skb)->dataref);
1135         dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1136         return dataref != 1;
1137 }
1138 
1139 /**
1140  *      skb_header_release - release reference to header
1141  *      @skb: buffer to operate on
1142  *
1143  *      Drop a reference to the header part of the buffer.  This is done
1144  *      by acquiring a payload reference.  You must not read from the header
1145  *      part of skb->data after this.
1146  *      Note : Check if you can use __skb_header_release() instead.
1147  */
1148 static inline void skb_header_release(struct sk_buff *skb)
1149 {
1150         BUG_ON(skb->nohdr);
1151         skb->nohdr = 1;
1152         atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
1153 }
1154 
1155 /**
1156  *      __skb_header_release - release reference to header
1157  *      @skb: buffer to operate on
1158  *
1159  *      Variant of skb_header_release() assuming skb is private to caller.
1160  *      We can avoid one atomic operation.
1161  */
1162 static inline void __skb_header_release(struct sk_buff *skb)
1163 {
1164         skb->nohdr = 1;
1165         atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1166 }
1167 
1168 
1169 /**
1170  *      skb_shared - is the buffer shared
1171  *      @skb: buffer to check
1172  *
1173  *      Returns true if more than one person has a reference to this
1174  *      buffer.
1175  */
1176 static inline int skb_shared(const struct sk_buff *skb)
1177 {
1178         return atomic_read(&skb->users) != 1;
1179 }
1180 
1181 /**
1182  *      skb_share_check - check if buffer is shared and if so clone it
1183  *      @skb: buffer to check
1184  *      @pri: priority for memory allocation
1185  *
1186  *      If the buffer is shared the buffer is cloned and the old copy
1187  *      drops a reference. A new clone with a single reference is returned.
1188  *      If the buffer is not shared the original buffer is returned. When
1189  *      being called from interrupt status or with spinlocks held pri must
1190  *      be GFP_ATOMIC.
1191  *
1192  *      NULL is returned on a memory allocation failure.
1193  */
1194 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1195 {
1196         might_sleep_if(pri & __GFP_WAIT);
1197         if (skb_shared(skb)) {
1198                 struct sk_buff *nskb = skb_clone(skb, pri);
1199 
1200                 if (likely(nskb))
1201                         consume_skb(skb);
1202                 else
1203                         kfree_skb(skb);
1204                 skb = nskb;
1205         }
1206         return skb;
1207 }
1208 
1209 /*
1210  *      Copy shared buffers into a new sk_buff. We effectively do COW on
1211  *      packets to handle cases where we have a local reader and forward
1212  *      and a couple of other messy ones. The normal one is tcpdumping
1213  *      a packet thats being forwarded.
1214  */
1215 
1216 /**
1217  *      skb_unshare - make a copy of a shared buffer
1218  *      @skb: buffer to check
1219  *      @pri: priority for memory allocation
1220  *
1221  *      If the socket buffer is a clone then this function creates a new
1222  *      copy of the data, drops a reference count on the old copy and returns
1223  *      the new copy with the reference count at 1. If the buffer is not a clone
1224  *      the original buffer is returned. When called with a spinlock held or
1225  *      from interrupt state @pri must be %GFP_ATOMIC
1226  *
1227  *      %NULL is returned on a memory allocation failure.
1228  */
1229 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1230                                           gfp_t pri)
1231 {
1232         might_sleep_if(pri & __GFP_WAIT);
1233         if (skb_cloned(skb)) {
1234                 struct sk_buff *nskb = skb_copy(skb, pri);
1235 
1236                 /* Free our shared copy */
1237                 if (likely(nskb))
1238                         consume_skb(skb);
1239                 else
1240                         kfree_skb(skb);
1241                 skb = nskb;
1242         }
1243         return skb;
1244 }
1245 
1246 /**
1247  *      skb_peek - peek at the head of an &sk_buff_head
1248  *      @list_: list to peek at
1249  *
1250  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1251  *      be careful with this one. A peek leaves the buffer on the
1252  *      list and someone else may run off with it. You must hold
1253  *      the appropriate locks or have a private queue to do this.
1254  *
1255  *      Returns %NULL for an empty list or a pointer to the head element.
1256  *      The reference count is not incremented and the reference is therefore
1257  *      volatile. Use with caution.
1258  */
1259 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1260 {
1261         struct sk_buff *skb = list_->next;
1262 
1263         if (skb == (struct sk_buff *)list_)
1264                 skb = NULL;
1265         return skb;
1266 }
1267 
1268 /**
1269  *      skb_peek_next - peek skb following the given one from a queue
1270  *      @skb: skb to start from
1271  *      @list_: list to peek at
1272  *
1273  *      Returns %NULL when the end of the list is met or a pointer to the
1274  *      next element. The reference count is not incremented and the
1275  *      reference is therefore volatile. Use with caution.
1276  */
1277 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1278                 const struct sk_buff_head *list_)
1279 {
1280         struct sk_buff *next = skb->next;
1281 
1282         if (next == (struct sk_buff *)list_)
1283                 next = NULL;
1284         return next;
1285 }
1286 
1287 /**
1288  *      skb_peek_tail - peek at the tail of an &sk_buff_head
1289  *      @list_: list to peek at
1290  *
1291  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1292  *      be careful with this one. A peek leaves the buffer on the
1293  *      list and someone else may run off with it. You must hold
1294  *      the appropriate locks or have a private queue to do this.
1295  *
1296  *      Returns %NULL for an empty list or a pointer to the tail element.
1297  *      The reference count is not incremented and the reference is therefore
1298  *      volatile. Use with caution.
1299  */
1300 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1301 {
1302         struct sk_buff *skb = list_->prev;
1303 
1304         if (skb == (struct sk_buff *)list_)
1305                 skb = NULL;
1306         return skb;
1307 
1308 }
1309 
1310 /**
1311  *      skb_queue_len   - get queue length
1312  *      @list_: list to measure
1313  *
1314  *      Return the length of an &sk_buff queue.
1315  */
1316 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1317 {
1318         return list_->qlen;
1319 }
1320 
1321 /**
1322  *      __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1323  *      @list: queue to initialize
1324  *
1325  *      This initializes only the list and queue length aspects of
1326  *      an sk_buff_head object.  This allows to initialize the list
1327  *      aspects of an sk_buff_head without reinitializing things like
1328  *      the spinlock.  It can also be used for on-stack sk_buff_head
1329  *      objects where the spinlock is known to not be used.
1330  */
1331 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1332 {
1333         list->prev = list->next = (struct sk_buff *)list;
1334         list->qlen = 0;
1335 }
1336 
1337 /*
1338  * This function creates a split out lock class for each invocation;
1339  * this is needed for now since a whole lot of users of the skb-queue
1340  * infrastructure in drivers have different locking usage (in hardirq)
1341  * than the networking core (in softirq only). In the long run either the
1342  * network layer or drivers should need annotation to consolidate the
1343  * main types of usage into 3 classes.
1344  */
1345 static inline void skb_queue_head_init(struct sk_buff_head *list)
1346 {
1347         spin_lock_init(&list->lock);
1348         __skb_queue_head_init(list);
1349 }
1350 
1351 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1352                 struct lock_class_key *class)
1353 {
1354         skb_queue_head_init(list);
1355         lockdep_set_class(&list->lock, class);
1356 }
1357 
1358 /*
1359  *      Insert an sk_buff on a list.
1360  *
1361  *      The "__skb_xxxx()" functions are the non-atomic ones that
1362  *      can only be called with interrupts disabled.
1363  */
1364 void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
1365                 struct sk_buff_head *list);
1366 static inline void __skb_insert(struct sk_buff *newsk,
1367                                 struct sk_buff *prev, struct sk_buff *next,
1368                                 struct sk_buff_head *list)
1369 {
1370         newsk->next = next;
1371         newsk->prev = prev;
1372         next->prev  = prev->next = newsk;
1373         list->qlen++;
1374 }
1375 
1376 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1377                                       struct sk_buff *prev,
1378                                       struct sk_buff *next)
1379 {
1380         struct sk_buff *first = list->next;
1381         struct sk_buff *last = list->prev;
1382 
1383         first->prev = prev;
1384         prev->next = first;
1385 
1386         last->next = next;
1387         next->prev = last;
1388 }
1389 
1390 /**
1391  *      skb_queue_splice - join two skb lists, this is designed for stacks
1392  *      @list: the new list to add
1393  *      @head: the place to add it in the first list
1394  */
1395 static inline void skb_queue_splice(const struct sk_buff_head *list,
1396                                     struct sk_buff_head *head)
1397 {
1398         if (!skb_queue_empty(list)) {
1399                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1400                 head->qlen += list->qlen;
1401         }
1402 }
1403 
1404 /**
1405  *      skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1406  *      @list: the new list to add
1407  *      @head: the place to add it in the first list
1408  *
1409  *      The list at @list is reinitialised
1410  */
1411 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1412                                          struct sk_buff_head *head)
1413 {
1414         if (!skb_queue_empty(list)) {
1415                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1416                 head->qlen += list->qlen;
1417                 __skb_queue_head_init(list);
1418         }
1419 }
1420 
1421 /**
1422  *      skb_queue_splice_tail - join two skb lists, each list being a queue
1423  *      @list: the new list to add
1424  *      @head: the place to add it in the first list
1425  */
1426 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1427                                          struct sk_buff_head *head)
1428 {
1429         if (!skb_queue_empty(list)) {
1430                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1431                 head->qlen += list->qlen;
1432         }
1433 }
1434 
1435 /**
1436  *      skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1437  *      @list: the new list to add
1438  *      @head: the place to add it in the first list
1439  *
1440  *      Each of the lists is a queue.
1441  *      The list at @list is reinitialised
1442  */
1443 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1444                                               struct sk_buff_head *head)
1445 {
1446         if (!skb_queue_empty(list)) {
1447                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1448                 head->qlen += list->qlen;
1449                 __skb_queue_head_init(list);
1450         }
1451 }
1452 
1453 /**
1454  *      __skb_queue_after - queue a buffer at the list head
1455  *      @list: list to use
1456  *      @prev: place after this buffer
1457  *      @newsk: buffer to queue
1458  *
1459  *      Queue a buffer int the middle of a list. This function takes no locks
1460  *      and you must therefore hold required locks before calling it.
1461  *
1462  *      A buffer cannot be placed on two lists at the same time.
1463  */
1464 static inline void __skb_queue_after(struct sk_buff_head *list,
1465                                      struct sk_buff *prev,
1466                                      struct sk_buff *newsk)
1467 {
1468         __skb_insert(newsk, prev, prev->next, list);
1469 }
1470 
1471 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1472                 struct sk_buff_head *list);
1473 
1474 static inline void __skb_queue_before(struct sk_buff_head *list,
1475                                       struct sk_buff *next,
1476                                       struct sk_buff *newsk)
1477 {
1478         __skb_insert(newsk, next->prev, next, list);
1479 }
1480 
1481 /**
1482  *      __skb_queue_head - queue a buffer at the list head
1483  *      @list: list to use
1484  *      @newsk: buffer to queue
1485  *
1486  *      Queue a buffer at the start of a list. This function takes no locks
1487  *      and you must therefore hold required locks before calling it.
1488  *
1489  *      A buffer cannot be placed on two lists at the same time.
1490  */
1491 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1492 static inline void __skb_queue_head(struct sk_buff_head *list,
1493                                     struct sk_buff *newsk)
1494 {
1495         __skb_queue_after(list, (struct sk_buff *)list, newsk);
1496 }
1497 
1498 /**
1499  *      __skb_queue_tail - queue a buffer at the list tail
1500  *      @list: list to use
1501  *      @newsk: buffer to queue
1502  *
1503  *      Queue a buffer at the end of a list. This function takes no locks
1504  *      and you must therefore hold required locks before calling it.
1505  *
1506  *      A buffer cannot be placed on two lists at the same time.
1507  */
1508 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1509 static inline void __skb_queue_tail(struct sk_buff_head *list,
1510                                    struct sk_buff *newsk)
1511 {
1512         __skb_queue_before(list, (struct sk_buff *)list, newsk);
1513 }
1514 
1515 /*
1516  * remove sk_buff from list. _Must_ be called atomically, and with
1517  * the list known..
1518  */
1519 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1520 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1521 {
1522         struct sk_buff *next, *prev;
1523 
1524         list->qlen--;
1525         next       = skb->next;
1526         prev       = skb->prev;
1527         skb->next  = skb->prev = NULL;
1528         next->prev = prev;
1529         prev->next = next;
1530 }
1531 
1532 /**
1533  *      __skb_dequeue - remove from the head of the queue
1534  *      @list: list to dequeue from
1535  *
1536  *      Remove the head of the list. This function does not take any locks
1537  *      so must be used with appropriate locks held only. The head item is
1538  *      returned or %NULL if the list is empty.
1539  */
1540 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1541 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1542 {
1543         struct sk_buff *skb = skb_peek(list);
1544         if (skb)
1545                 __skb_unlink(skb, list);
1546         return skb;
1547 }
1548 
1549 /**
1550  *      __skb_dequeue_tail - remove from the tail of the queue
1551  *      @list: list to dequeue from
1552  *
1553  *      Remove the tail of the list. This function does not take any locks
1554  *      so must be used with appropriate locks held only. The tail item is
1555  *      returned or %NULL if the list is empty.
1556  */
1557 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1558 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1559 {
1560         struct sk_buff *skb = skb_peek_tail(list);
1561         if (skb)
1562                 __skb_unlink(skb, list);
1563         return skb;
1564 }
1565 
1566 
1567 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1568 {
1569         return skb->data_len;
1570 }
1571 
1572 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1573 {
1574         return skb->len - skb->data_len;
1575 }
1576 
1577 static inline int skb_pagelen(const struct sk_buff *skb)
1578 {
1579         int i, len = 0;
1580 
1581         for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1582                 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1583         return len + skb_headlen(skb);
1584 }
1585 
1586 /**
1587  * __skb_fill_page_desc - initialise a paged fragment in an skb
1588  * @skb: buffer containing fragment to be initialised
1589  * @i: paged fragment index to initialise
1590  * @page: the page to use for this fragment
1591  * @off: the offset to the data with @page
1592  * @size: the length of the data
1593  *
1594  * Initialises the @i'th fragment of @skb to point to &size bytes at
1595  * offset @off within @page.
1596  *
1597  * Does not take any additional reference on the fragment.
1598  */
1599 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1600                                         struct page *page, int off, int size)
1601 {
1602         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1603 
1604         /*
1605          * Propagate page pfmemalloc to the skb if we can. The problem is
1606          * that not all callers have unique ownership of the page but rely
1607          * on page_is_pfmemalloc doing the right thing(tm).
1608          */
1609         frag->page.p              = page;
1610         frag->page_offset         = off;
1611         skb_frag_size_set(frag, size);
1612 
1613         page = compound_head(page);
1614         if (page_is_pfmemalloc(page))
1615                 skb->pfmemalloc = true;
1616 }
1617 
1618 /**
1619  * skb_fill_page_desc - initialise a paged fragment in an skb
1620  * @skb: buffer containing fragment to be initialised
1621  * @i: paged fragment index to initialise
1622  * @page: the page to use for this fragment
1623  * @off: the offset to the data with @page
1624  * @size: the length of the data
1625  *
1626  * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1627  * @skb to point to @size bytes at offset @off within @page. In
1628  * addition updates @skb such that @i is the last fragment.
1629  *
1630  * Does not take any additional reference on the fragment.
1631  */
1632 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1633                                       struct page *page, int off, int size)
1634 {
1635         __skb_fill_page_desc(skb, i, page, off, size);
1636         skb_shinfo(skb)->nr_frags = i + 1;
1637 }
1638 
1639 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
1640                      int size, unsigned int truesize);
1641 
1642 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
1643                           unsigned int truesize);
1644 
1645 #define SKB_PAGE_ASSERT(skb)    BUG_ON(skb_shinfo(skb)->nr_frags)
1646 #define SKB_FRAG_ASSERT(skb)    BUG_ON(skb_has_frag_list(skb))
1647 #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
1648 
1649 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1650 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1651 {
1652         return skb->head + skb->tail;
1653 }
1654 
1655 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1656 {
1657         skb->tail = skb->data - skb->head;
1658 }
1659 
1660 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1661 {
1662         skb_reset_tail_pointer(skb);
1663         skb->tail += offset;
1664 }
1665 
1666 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1667 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1668 {
1669         return skb->tail;
1670 }
1671 
1672 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1673 {
1674         skb->tail = skb->data;
1675 }
1676 
1677 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1678 {
1679         skb->tail = skb->data + offset;
1680 }
1681 
1682 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1683 
1684 /*
1685  *      Add data to an sk_buff
1686  */
1687 unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
1688 unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1689 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1690 {
1691         unsigned char *tmp = skb_tail_pointer(skb);
1692         SKB_LINEAR_ASSERT(skb);
1693         skb->tail += len;
1694         skb->len  += len;
1695         return tmp;
1696 }
1697 
1698 unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1699 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1700 {
1701         skb->data -= len;
1702         skb->len  += len;
1703         return skb->data;
1704 }
1705 
1706 unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1707 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1708 {
1709         skb->len -= len;
1710         BUG_ON(skb->len < skb->data_len);
1711         return skb->data += len;
1712 }
1713 
1714 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1715 {
1716         return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1717 }
1718 
1719 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1720 
1721 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1722 {
1723         if (len > skb_headlen(skb) &&
1724             !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1725                 return NULL;
1726         skb->len -= len;
1727         return skb->data += len;
1728 }
1729 
1730 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1731 {
1732         return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1733 }
1734 
1735 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1736 {
1737         if (likely(len <= skb_headlen(skb)))
1738                 return 1;
1739         if (unlikely(len > skb->len))
1740                 return 0;
1741         return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1742 }
1743 
1744 /**
1745  *      skb_headroom - bytes at buffer head
1746  *      @skb: buffer to check
1747  *
1748  *      Return the number of bytes of free space at the head of an &sk_buff.
1749  */
1750 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1751 {
1752         return skb->data - skb->head;
1753 }
1754 
1755 /**
1756  *      skb_tailroom - bytes at buffer end
1757  *      @skb: buffer to check
1758  *
1759  *      Return the number of bytes of free space at the tail of an sk_buff
1760  */
1761 static inline int skb_tailroom(const struct sk_buff *skb)
1762 {
1763         return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1764 }
1765 
1766 /**
1767  *      skb_availroom - bytes at buffer end
1768  *      @skb: buffer to check
1769  *
1770  *      Return the number of bytes of free space at the tail of an sk_buff
1771  *      allocated by sk_stream_alloc()
1772  */
1773 static inline int skb_availroom(const struct sk_buff *skb)
1774 {
1775         if (skb_is_nonlinear(skb))
1776                 return 0;
1777 
1778         return skb->end - skb->tail - skb->reserved_tailroom;
1779 }
1780 
1781 /**
1782  *      skb_reserve - adjust headroom
1783  *      @skb: buffer to alter
1784  *      @len: bytes to move
1785  *
1786  *      Increase the headroom of an empty &sk_buff by reducing the tail
1787  *      room. This is only allowed for an empty buffer.
1788  */
1789 static inline void skb_reserve(struct sk_buff *skb, int len)
1790 {
1791         skb->data += len;
1792         skb->tail += len;
1793 }
1794 
1795 #define ENCAP_TYPE_ETHER        0
1796 #define ENCAP_TYPE_IPPROTO      1
1797 
1798 static inline void skb_set_inner_protocol(struct sk_buff *skb,
1799                                           __be16 protocol)
1800 {
1801         skb->inner_protocol = protocol;
1802         skb->inner_protocol_type = ENCAP_TYPE_ETHER;
1803 }
1804 
1805 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
1806                                          __u8 ipproto)
1807 {
1808         skb->inner_ipproto = ipproto;
1809         skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
1810 }
1811 
1812 static inline void skb_reset_inner_headers(struct sk_buff *skb)
1813 {
1814         skb->inner_mac_header = skb->mac_header;
1815         skb->inner_network_header = skb->network_header;
1816         skb->inner_transport_header = skb->transport_header;
1817 }
1818 
1819 static inline void skb_reset_mac_len(struct sk_buff *skb)
1820 {
1821         skb->mac_len = skb->network_header - skb->mac_header;
1822 }
1823 
1824 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
1825                                                         *skb)
1826 {
1827         return skb->head + skb->inner_transport_header;
1828 }
1829 
1830 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
1831 {
1832         skb->inner_transport_header = skb->data - skb->head;
1833 }
1834 
1835 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
1836                                                    const int offset)
1837 {
1838         skb_reset_inner_transport_header(skb);
1839         skb->inner_transport_header += offset;
1840 }
1841 
1842 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
1843 {
1844         return skb->head + skb->inner_network_header;
1845 }
1846 
1847 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
1848 {
1849         skb->inner_network_header = skb->data - skb->head;
1850 }
1851 
1852 static inline void skb_set_inner_network_header(struct sk_buff *skb,
1853                                                 const int offset)
1854 {
1855         skb_reset_inner_network_header(skb);
1856         skb->inner_network_header += offset;
1857 }
1858 
1859 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
1860 {
1861         return skb->head + skb->inner_mac_header;
1862 }
1863 
1864 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
1865 {
1866         skb->inner_mac_header = skb->data - skb->head;
1867 }
1868 
1869 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
1870                                             const int offset)
1871 {
1872         skb_reset_inner_mac_header(skb);
1873         skb->inner_mac_header += offset;
1874 }
1875 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
1876 {
1877         return skb->transport_header != (typeof(skb->transport_header))~0U;
1878 }
1879 
1880 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1881 {
1882         return skb->head + skb->transport_header;
1883 }
1884 
1885 static inline void skb_reset_transport_header(struct sk_buff *skb)
1886 {
1887         skb->transport_header = skb->data - skb->head;
1888 }
1889 
1890 static inline void skb_set_transport_header(struct sk_buff *skb,
1891                                             const int offset)
1892 {
1893         skb_reset_transport_header(skb);
1894         skb->transport_header += offset;
1895 }
1896 
1897 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1898 {
1899         return skb->head + skb->network_header;
1900 }
1901 
1902 static inline void skb_reset_network_header(struct sk_buff *skb)
1903 {
1904         skb->network_header = skb->data - skb->head;
1905 }
1906 
1907 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1908 {
1909         skb_reset_network_header(skb);
1910         skb->network_header += offset;
1911 }
1912 
1913 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1914 {
1915         return skb->head + skb->mac_header;
1916 }
1917 
1918 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1919 {
1920         return skb->mac_header != (typeof(skb->mac_header))~0U;
1921 }
1922 
1923 static inline void skb_reset_mac_header(struct sk_buff *skb)
1924 {
1925         skb->mac_header = skb->data - skb->head;
1926 }
1927 
1928 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1929 {
1930         skb_reset_mac_header(skb);
1931         skb->mac_header += offset;
1932 }
1933 
1934 static inline void skb_pop_mac_header(struct sk_buff *skb)
1935 {
1936         skb->mac_header = skb->network_header;
1937 }
1938 
1939 static inline void skb_probe_transport_header(struct sk_buff *skb,
1940                                               const int offset_hint)
1941 {
1942         struct flow_keys keys;
1943 
1944         if (skb_transport_header_was_set(skb))
1945                 return;
1946         else if (skb_flow_dissect_flow_keys(skb, &keys))
1947                 skb_set_transport_header(skb, keys.control.thoff);
1948         else
1949                 skb_set_transport_header(skb, offset_hint);
1950 }
1951 
1952 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
1953 {
1954         if (skb_mac_header_was_set(skb)) {
1955                 const unsigned char *old_mac = skb_mac_header(skb);
1956 
1957                 skb_set_mac_header(skb, -skb->mac_len);
1958                 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
1959         }
1960 }
1961 
1962 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1963 {
1964         return skb->csum_start - skb_headroom(skb);
1965 }
1966 
1967 static inline int skb_transport_offset(const struct sk_buff *skb)
1968 {
1969         return skb_transport_header(skb) - skb->data;
1970 }
1971 
1972 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1973 {
1974         return skb->transport_header - skb->network_header;
1975 }
1976 
1977 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
1978 {
1979         return skb->inner_transport_header - skb->inner_network_header;
1980 }
1981 
1982 static inline int skb_network_offset(const struct sk_buff *skb)
1983 {
1984         return skb_network_header(skb) - skb->data;
1985 }
1986 
1987 static inline int skb_inner_network_offset(const struct sk_buff *skb)
1988 {
1989         return skb_inner_network_header(skb) - skb->data;
1990 }
1991 
1992 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1993 {
1994         return pskb_may_pull(skb, skb_network_offset(skb) + len);
1995 }
1996 
1997 /*
1998  * CPUs often take a performance hit when accessing unaligned memory
1999  * locations. The actual performance hit varies, it can be small if the
2000  * hardware handles it or large if we have to take an exception and fix it
2001  * in software.
2002  *
2003  * Since an ethernet header is 14 bytes network drivers often end up with
2004  * the IP header at an unaligned offset. The IP header can be aligned by
2005  * shifting the start of the packet by 2 bytes. Drivers should do this
2006  * with:
2007  *
2008  * skb_reserve(skb, NET_IP_ALIGN);
2009  *
2010  * The downside to this alignment of the IP header is that the DMA is now
2011  * unaligned. On some architectures the cost of an unaligned DMA is high
2012  * and this cost outweighs the gains made by aligning the IP header.
2013  *
2014  * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2015  * to be overridden.
2016  */
2017 #ifndef NET_IP_ALIGN
2018 #define NET_IP_ALIGN    2
2019 #endif
2020 
2021 /*
2022  * The networking layer reserves some headroom in skb data (via
2023  * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2024  * the header has to grow. In the default case, if the header has to grow
2025  * 32 bytes or less we avoid the reallocation.
2026  *
2027  * Unfortunately this headroom changes the DMA alignment of the resulting
2028  * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2029  * on some architectures. An architecture can override this value,
2030  * perhaps setting it to a cacheline in size (since that will maintain
2031  * cacheline alignment of the DMA). It must be a power of 2.
2032  *
2033  * Various parts of the networking layer expect at least 32 bytes of
2034  * headroom, you should not reduce this.
2035  *
2036  * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2037  * to reduce average number of cache lines per packet.
2038  * get_rps_cpus() for example only access one 64 bytes aligned block :
2039  * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2040  */
2041 #ifndef NET_SKB_PAD
2042 #define NET_SKB_PAD     max(32, L1_CACHE_BYTES)
2043 #endif
2044 
2045 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2046 
2047 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2048 {
2049         if (unlikely(skb_is_nonlinear(skb))) {
2050                 WARN_ON(1);
2051                 return;
2052         }
2053         skb->len = len;
2054         skb_set_tail_pointer(skb, len);
2055 }
2056 
2057 void skb_trim(struct sk_buff *skb, unsigned int len);
2058 
2059 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2060 {
2061         if (skb->data_len)
2062                 return ___pskb_trim(skb, len);
2063         __skb_trim(skb, len);
2064         return 0;
2065 }
2066 
2067 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2068 {
2069         return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2070 }
2071 
2072 /**
2073  *      pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2074  *      @skb: buffer to alter
2075  *      @len: new length
2076  *
2077  *      This is identical to pskb_trim except that the caller knows that
2078  *      the skb is not cloned so we should never get an error due to out-
2079  *      of-memory.
2080  */
2081 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2082 {
2083         int err = pskb_trim(skb, len);
2084         BUG_ON(err);
2085 }
2086 
2087 /**
2088  *      skb_orphan - orphan a buffer
2089  *      @skb: buffer to orphan
2090  *
2091  *      If a buffer currently has an owner then we call the owner's
2092  *      destructor function and make the @skb unowned. The buffer continues
2093  *      to exist but is no longer charged to its former owner.
2094  */
2095 static inline void skb_orphan(struct sk_buff *skb)
2096 {
2097         if (skb->destructor) {
2098                 skb->destructor(skb);
2099                 skb->destructor = NULL;
2100                 skb->sk         = NULL;
2101         } else {
2102                 BUG_ON(skb->sk);
2103         }
2104 }
2105 
2106 /**
2107  *      skb_orphan_frags - orphan the frags contained in a buffer
2108  *      @skb: buffer to orphan frags from
2109  *      @gfp_mask: allocation mask for replacement pages
2110  *
2111  *      For each frag in the SKB which needs a destructor (i.e. has an
2112  *      owner) create a copy of that frag and release the original
2113  *      page by calling the destructor.
2114  */
2115 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2116 {
2117         if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
2118                 return 0;
2119         return skb_copy_ubufs(skb, gfp_mask);
2120 }
2121 
2122 /**
2123  *      __skb_queue_purge - empty a list
2124  *      @list: list to empty
2125  *
2126  *      Delete all buffers on an &sk_buff list. Each buffer is removed from
2127  *      the list and one reference dropped. This function does not take the
2128  *      list lock and the caller must hold the relevant locks to use it.
2129  */
2130 void skb_queue_purge(struct sk_buff_head *list);
2131 static inline void __skb_queue_purge(struct sk_buff_head *list)
2132 {
2133         struct sk_buff *skb;
2134         while ((skb = __skb_dequeue(list)) != NULL)
2135                 kfree_skb(skb);
2136 }
2137 
2138 void *netdev_alloc_frag(unsigned int fragsz);
2139 
2140 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2141                                    gfp_t gfp_mask);
2142 
2143 /**
2144  *      netdev_alloc_skb - allocate an skbuff for rx on a specific device
2145  *      @dev: network device to receive on
2146  *      @length: length to allocate
2147  *
2148  *      Allocate a new &sk_buff and assign it a usage count of one. The
2149  *      buffer has unspecified headroom built in. Users should allocate
2150  *      the headroom they think they need without accounting for the
2151  *      built in space. The built in space is used for optimisations.
2152  *
2153  *      %NULL is returned if there is no free memory. Although this function
2154  *      allocates memory it can be called from an interrupt.
2155  */
2156 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2157                                                unsigned int length)
2158 {
2159         return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2160 }
2161 
2162 /* legacy helper around __netdev_alloc_skb() */
2163 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2164                                               gfp_t gfp_mask)
2165 {
2166         return __netdev_alloc_skb(NULL, length, gfp_mask);
2167 }
2168 
2169 /* legacy helper around netdev_alloc_skb() */
2170 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2171 {
2172         return netdev_alloc_skb(NULL, length);
2173 }
2174 
2175 
2176 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2177                 unsigned int length, gfp_t gfp)
2178 {
2179         struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2180 
2181         if (NET_IP_ALIGN && skb)
2182                 skb_reserve(skb, NET_IP_ALIGN);
2183         return skb;
2184 }
2185 
2186 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2187                 unsigned int length)
2188 {
2189         return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2190 }
2191 
2192 static inline void skb_free_frag(void *addr)
2193 {
2194         __free_page_frag(addr);
2195 }
2196 
2197 void *napi_alloc_frag(unsigned int fragsz);
2198 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2199                                  unsigned int length, gfp_t gfp_mask);
2200 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2201                                              unsigned int length)
2202 {
2203         return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2204 }
2205 
2206 /**
2207  * __dev_alloc_pages - allocate page for network Rx
2208  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2209  * @order: size of the allocation
2210  *
2211  * Allocate a new page.
2212  *
2213  * %NULL is returned if there is no free memory.
2214 */
2215 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2216                                              unsigned int order)
2217 {
2218         /* This piece of code contains several assumptions.
2219          * 1.  This is for device Rx, therefor a cold page is preferred.
2220          * 2.  The expectation is the user wants a compound page.
2221          * 3.  If requesting a order 0 page it will not be compound
2222          *     due to the check to see if order has a value in prep_new_page
2223          * 4.  __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2224          *     code in gfp_to_alloc_flags that should be enforcing this.
2225          */
2226         gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC;
2227 
2228         return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2229 }
2230 
2231 static inline struct page *dev_alloc_pages(unsigned int order)
2232 {
2233         return __dev_alloc_pages(GFP_ATOMIC, order);
2234 }
2235 
2236 /**
2237  * __dev_alloc_page - allocate a page for network Rx
2238  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2239  *
2240  * Allocate a new page.
2241  *
2242  * %NULL is returned if there is no free memory.
2243  */
2244 static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2245 {
2246         return __dev_alloc_pages(gfp_mask, 0);
2247 }
2248 
2249 static inline struct page *dev_alloc_page(void)
2250 {
2251         return __dev_alloc_page(GFP_ATOMIC);
2252 }
2253 
2254 /**
2255  *      skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2256  *      @page: The page that was allocated from skb_alloc_page
2257  *      @skb: The skb that may need pfmemalloc set
2258  */
2259 static inline void skb_propagate_pfmemalloc(struct page *page,
2260                                              struct sk_buff *skb)
2261 {
2262         if (page_is_pfmemalloc(page))
2263                 skb->pfmemalloc = true;
2264 }
2265 
2266 /**
2267  * skb_frag_page - retrieve the page referred to by a paged fragment
2268  * @frag: the paged fragment
2269  *
2270  * Returns the &struct page associated with @frag.
2271  */
2272 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2273 {
2274         return frag->page.p;
2275 }
2276 
2277 /**
2278  * __skb_frag_ref - take an addition reference on a paged fragment.
2279  * @frag: the paged fragment
2280  *
2281  * Takes an additional reference on the paged fragment @frag.
2282  */
2283 static inline void __skb_frag_ref(skb_frag_t *frag)
2284 {
2285         get_page(skb_frag_page(frag));
2286 }
2287 
2288 /**
2289  * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2290  * @skb: the buffer
2291  * @f: the fragment offset.
2292  *
2293  * Takes an additional reference on the @f'th paged fragment of @skb.
2294  */
2295 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2296 {
2297         __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2298 }
2299 
2300 /**
2301  * __skb_frag_unref - release a reference on a paged fragment.
2302  * @frag: the paged fragment
2303  *
2304  * Releases a reference on the paged fragment @frag.
2305  */
2306 static inline void __skb_frag_unref(skb_frag_t *frag)
2307 {
2308         put_page(skb_frag_page(frag));
2309 }
2310 
2311 /**
2312  * skb_frag_unref - release a reference on a paged fragment of an skb.
2313  * @skb: the buffer
2314  * @f: the fragment offset
2315  *
2316  * Releases a reference on the @f'th paged fragment of @skb.
2317  */
2318 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2319 {
2320         __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2321 }
2322 
2323 /**
2324  * skb_frag_address - gets the address of the data contained in a paged fragment
2325  * @frag: the paged fragment buffer
2326  *
2327  * Returns the address of the data within @frag. The page must already
2328  * be mapped.
2329  */
2330 static inline void *skb_frag_address(const skb_frag_t *frag)
2331 {
2332         return page_address(skb_frag_page(frag)) + frag->page_offset;
2333 }
2334 
2335 /**
2336  * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2337  * @frag: the paged fragment buffer
2338  *
2339  * Returns the address of the data within @frag. Checks that the page
2340  * is mapped and returns %NULL otherwise.
2341  */
2342 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2343 {
2344         void *ptr = page_address(skb_frag_page(frag));
2345         if (unlikely(!ptr))
2346                 return NULL;
2347 
2348         return ptr + frag->page_offset;
2349 }
2350 
2351 /**
2352  * __skb_frag_set_page - sets the page contained in a paged fragment
2353  * @frag: the paged fragment
2354  * @page: the page to set
2355  *
2356  * Sets the fragment @frag to contain @page.
2357  */
2358 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2359 {
2360         frag->page.p = page;
2361 }
2362 
2363 /**
2364  * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2365  * @skb: the buffer
2366  * @f: the fragment offset
2367  * @page: the page to set
2368  *
2369  * Sets the @f'th fragment of @skb to contain @page.
2370  */
2371 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2372                                      struct page *page)
2373 {
2374         __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2375 }
2376 
2377 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2378 
2379 /**
2380  * skb_frag_dma_map - maps a paged fragment via the DMA API
2381  * @dev: the device to map the fragment to
2382  * @frag: the paged fragment to map
2383  * @offset: the offset within the fragment (starting at the
2384  *          fragment's own offset)
2385  * @size: the number of bytes to map
2386  * @dir: the direction of the mapping (%PCI_DMA_*)
2387  *
2388  * Maps the page associated with @frag to @device.
2389  */
2390 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2391                                           const skb_frag_t *frag,
2392                                           size_t offset, size_t size,
2393                                           enum dma_data_direction dir)
2394 {
2395         return dma_map_page(dev, skb_frag_page(frag),
2396                             frag->page_offset + offset, size, dir);
2397 }
2398 
2399 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2400                                         gfp_t gfp_mask)
2401 {
2402         return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2403 }
2404 
2405 
2406 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
2407                                                   gfp_t gfp_mask)
2408 {
2409         return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
2410 }
2411 
2412 
2413 /**
2414  *      skb_clone_writable - is the header of a clone writable
2415  *      @skb: buffer to check
2416  *      @len: length up to which to write
2417  *
2418  *      Returns true if modifying the header part of the cloned buffer
2419  *      does not requires the data to be copied.
2420  */
2421 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2422 {
2423         return !skb_header_cloned(skb) &&
2424                skb_headroom(skb) + len <= skb->hdr_len;
2425 }
2426 
2427 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2428                             int cloned)
2429 {
2430         int delta = 0;
2431 
2432         if (headroom > skb_headroom(skb))
2433                 delta = headroom - skb_headroom(skb);
2434 
2435         if (delta || cloned)
2436                 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2437                                         GFP_ATOMIC);
2438         return 0;
2439 }
2440 
2441 /**
2442  *      skb_cow - copy header of skb when it is required
2443  *      @skb: buffer to cow
2444  *      @headroom: needed headroom
2445  *
2446  *      If the skb passed lacks sufficient headroom or its data part
2447  *      is shared, data is reallocated. If reallocation fails, an error
2448  *      is returned and original skb is not changed.
2449  *
2450  *      The result is skb with writable area skb->head...skb->tail
2451  *      and at least @headroom of space at head.
2452  */
2453 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2454 {
2455         return __skb_cow(skb, headroom, skb_cloned(skb));
2456 }
2457 
2458 /**
2459  *      skb_cow_head - skb_cow but only making the head writable
2460  *      @skb: buffer to cow
2461  *      @headroom: needed headroom
2462  *
2463  *      This function is identical to skb_cow except that we replace the
2464  *      skb_cloned check by skb_header_cloned.  It should be used when
2465  *      you only need to push on some header and do not need to modify
2466  *      the data.
2467  */
2468 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2469 {
2470         return __skb_cow(skb, headroom, skb_header_cloned(skb));
2471 }
2472 
2473 /**
2474  *      skb_padto       - pad an skbuff up to a minimal size
2475  *      @skb: buffer to pad
2476  *      @len: minimal length
2477  *
2478  *      Pads up a buffer to ensure the trailing bytes exist and are
2479  *      blanked. If the buffer already contains sufficient data it
2480  *      is untouched. Otherwise it is extended. Returns zero on
2481  *      success. The skb is freed on error.
2482  */
2483 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2484 {
2485         unsigned int size = skb->len;
2486         if (likely(size >= len))
2487                 return 0;
2488         return skb_pad(skb, len - size);
2489 }
2490 
2491 /**
2492  *      skb_put_padto - increase size and pad an skbuff up to a minimal size
2493  *      @skb: buffer to pad
2494  *      @len: minimal length
2495  *
2496  *      Pads up a buffer to ensure the trailing bytes exist and are
2497  *      blanked. If the buffer already contains sufficient data it
2498  *      is untouched. Otherwise it is extended. Returns zero on
2499  *      success. The skb is freed on error.
2500  */
2501 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
2502 {
2503         unsigned int size = skb->len;
2504 
2505         if (unlikely(size < len)) {
2506                 len -= size;
2507                 if (skb_pad(skb, len))
2508                         return -ENOMEM;
2509                 __skb_put(skb, len);
2510         }
2511         return 0;
2512 }
2513 
2514 static inline int skb_add_data(struct sk_buff *skb,
2515                                struct iov_iter *from, int copy)
2516 {
2517         const int off = skb->len;
2518 
2519         if (skb->ip_summed == CHECKSUM_NONE) {
2520                 __wsum csum = 0;
2521                 if (csum_and_copy_from_iter(skb_put(skb, copy), copy,
2522                                             &csum, from) == copy) {
2523                         skb->csum = csum_block_add(skb->csum, csum, off);
2524                         return 0;
2525                 }
2526         } else if (copy_from_iter(skb_put(skb, copy), copy, from) == copy)
2527                 return 0;
2528 
2529         __skb_trim(skb, off);
2530         return -EFAULT;
2531 }
2532 
2533 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2534                                     const struct page *page, int off)
2535 {
2536         if (i) {
2537                 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2538 
2539                 return page == skb_frag_page(frag) &&
2540                        off == frag->page_offset + skb_frag_size(frag);
2541         }
2542         return false;
2543 }
2544 
2545 static inline int __skb_linearize(struct sk_buff *skb)
2546 {
2547         return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2548 }
2549 
2550 /**
2551  *      skb_linearize - convert paged skb to linear one
2552  *      @skb: buffer to linarize
2553  *
2554  *      If there is no free memory -ENOMEM is returned, otherwise zero
2555  *      is returned and the old skb data released.
2556  */
2557 static inline int skb_linearize(struct sk_buff *skb)
2558 {
2559         return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2560 }
2561 
2562 /**
2563  * skb_has_shared_frag - can any frag be overwritten
2564  * @skb: buffer to test
2565  *
2566  * Return true if the skb has at least one frag that might be modified
2567  * by an external entity (as in vmsplice()/sendfile())
2568  */
2569 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2570 {
2571         return skb_is_nonlinear(skb) &&
2572                skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2573 }
2574 
2575 /**
2576  *      skb_linearize_cow - make sure skb is linear and writable
2577  *      @skb: buffer to process
2578  *
2579  *      If there is no free memory -ENOMEM is returned, otherwise zero
2580  *      is returned and the old skb data released.
2581  */
2582 static inline int skb_linearize_cow(struct sk_buff *skb)
2583 {
2584         return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2585                __skb_linearize(skb) : 0;
2586 }
2587 
2588 /**
2589  *      skb_postpull_rcsum - update checksum for received skb after pull
2590  *      @skb: buffer to update
2591  *      @start: start of data before pull
2592  *      @len: length of data pulled
2593  *
2594  *      After doing a pull on a received packet, you need to call this to
2595  *      update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2596  *      CHECKSUM_NONE so that it can be recomputed from scratch.
2597  */
2598 
2599 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2600                                       const void *start, unsigned int len)
2601 {
2602         if (skb->ip_summed == CHECKSUM_COMPLETE)
2603                 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
2604         else if (skb->ip_summed == CHECKSUM_PARTIAL &&
2605                  skb_checksum_start_offset(skb) < 0)
2606                 skb->ip_summed = CHECKSUM_NONE;
2607 }
2608 
2609 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2610 
2611 /**
2612  *      pskb_trim_rcsum - trim received skb and update checksum
2613  *      @skb: buffer to trim
2614  *      @len: new length
2615  *
2616  *      This is exactly the same as pskb_trim except that it ensures the
2617  *      checksum of received packets are still valid after the operation.
2618  */
2619 
2620 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2621 {
2622         if (likely(len >= skb->len))
2623                 return 0;
2624         if (skb->ip_summed == CHECKSUM_COMPLETE)
2625                 skb->ip_summed = CHECKSUM_NONE;
2626         return __pskb_trim(skb, len);
2627 }
2628 
2629 #define skb_queue_walk(queue, skb) \
2630                 for (skb = (queue)->next;                                       \
2631                      skb != (struct sk_buff *)(queue);                          \
2632                      skb = skb->next)
2633 
2634 #define skb_queue_walk_safe(queue, skb, tmp)                                    \
2635                 for (skb = (queue)->next, tmp = skb->next;                      \
2636                      skb != (struct sk_buff *)(queue);                          \
2637                      skb = tmp, tmp = skb->next)
2638 
2639 #define skb_queue_walk_from(queue, skb)                                         \
2640                 for (; skb != (struct sk_buff *)(queue);                        \
2641                      skb = skb->next)
2642 
2643 #define skb_queue_walk_from_safe(queue, skb, tmp)                               \
2644                 for (tmp = skb->next;                                           \
2645                      skb != (struct sk_buff *)(queue);                          \
2646                      skb = tmp, tmp = skb->next)
2647 
2648 #define skb_queue_reverse_walk(queue, skb) \
2649                 for (skb = (queue)->prev;                                       \
2650                      skb != (struct sk_buff *)(queue);                          \
2651                      skb = skb->prev)
2652 
2653 #define skb_queue_reverse_walk_safe(queue, skb, tmp)                            \
2654                 for (skb = (queue)->prev, tmp = skb->prev;                      \
2655                      skb != (struct sk_buff *)(queue);                          \
2656                      skb = tmp, tmp = skb->prev)
2657 
2658 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp)                       \
2659                 for (tmp = skb->prev;                                           \
2660                      skb != (struct sk_buff *)(queue);                          \
2661                      skb = tmp, tmp = skb->prev)
2662 
2663 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2664 {
2665         return skb_shinfo(skb)->frag_list != NULL;
2666 }
2667 
2668 static inline void skb_frag_list_init(struct sk_buff *skb)
2669 {
2670         skb_shinfo(skb)->frag_list = NULL;
2671 }
2672 
2673 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2674 {
2675         frag->next = skb_shinfo(skb)->frag_list;
2676         skb_shinfo(skb)->frag_list = frag;
2677 }
2678 
2679 #define skb_walk_frags(skb, iter)       \
2680         for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2681 
2682 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2683                                     int *peeked, int *off, int *err);
2684 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
2685                                   int *err);
2686 unsigned int datagram_poll(struct file *file, struct socket *sock,
2687                            struct poll_table_struct *wait);
2688 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
2689                            struct iov_iter *to, int size);
2690 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
2691                                         struct msghdr *msg, int size)
2692 {
2693         return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
2694 }
2695 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
2696                                    struct msghdr *msg);
2697 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
2698                                  struct iov_iter *from, int len);
2699 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
2700 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2701 void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);
2702 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
2703 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
2704 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
2705 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
2706                               int len, __wsum csum);
2707 ssize_t skb_socket_splice(struct sock *sk,
2708                           struct pipe_inode_info *pipe,
2709                           struct splice_pipe_desc *spd);
2710 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
2711                     struct pipe_inode_info *pipe, unsigned int len,
2712                     unsigned int flags,
2713                     ssize_t (*splice_cb)(struct sock *,
2714                                          struct pipe_inode_info *,
2715                                          struct splice_pipe_desc *));
2716 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2717 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
2718 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
2719                  int len, int hlen);
2720 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
2721 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
2722 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
2723 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
2724 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
2725 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
2726 int skb_ensure_writable(struct sk_buff *skb, int write_len);
2727 int skb_vlan_pop(struct sk_buff *skb);
2728 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
2729 
2730 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
2731 {
2732         return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
2733 }
2734 
2735 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
2736 {
2737         return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
2738 }
2739 
2740 struct skb_checksum_ops {
2741         __wsum (*update)(const void *mem, int len, __wsum wsum);
2742         __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
2743 };
2744 
2745 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2746                       __wsum csum, const struct skb_checksum_ops *ops);
2747 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
2748                     __wsum csum);
2749 
2750 static inline void * __must_check
2751 __skb_header_pointer(const struct sk_buff *skb, int offset,
2752                      int len, void *data, int hlen, void *buffer)
2753 {
2754         if (hlen - offset >= len)
2755                 return data + offset;
2756 
2757         if (!skb ||
2758             skb_copy_bits(skb, offset, buffer, len) < 0)
2759                 return NULL;
2760 
2761         return buffer;
2762 }
2763 
2764 static inline void * __must_check
2765 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
2766 {
2767         return __skb_header_pointer(skb, offset, len, skb->data,
2768                                     skb_headlen(skb), buffer);
2769 }
2770 
2771 /**
2772  *      skb_needs_linearize - check if we need to linearize a given skb
2773  *                            depending on the given device features.
2774  *      @skb: socket buffer to check
2775  *      @features: net device features
2776  *
2777  *      Returns true if either:
2778  *      1. skb has frag_list and the device doesn't support FRAGLIST, or
2779  *      2. skb is fragmented and the device does not support SG.
2780  */
2781 static inline bool skb_needs_linearize(struct sk_buff *skb,
2782                                        netdev_features_t features)
2783 {
2784         return skb_is_nonlinear(skb) &&
2785                ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
2786                 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
2787 }
2788 
2789 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2790                                              void *to,
2791                                              const unsigned int len)
2792 {
2793         memcpy(to, skb->data, len);
2794 }
2795 
2796 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2797                                                     const int offset, void *to,
2798                                                     const unsigned int len)
2799 {
2800         memcpy(to, skb->data + offset, len);
2801 }
2802 
2803 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2804                                            const void *from,
2805                                            const unsigned int len)
2806 {
2807         memcpy(skb->data, from, len);
2808 }
2809 
2810 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2811                                                   const int offset,
2812                                                   const void *from,
2813                                                   const unsigned int len)
2814 {
2815         memcpy(skb->data + offset, from, len);
2816 }
2817 
2818 void skb_init(void);
2819 
2820 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2821 {
2822         return skb->tstamp;
2823 }
2824 
2825 /**
2826  *      skb_get_timestamp - get timestamp from a skb
2827  *      @skb: skb to get stamp from
2828  *      @stamp: pointer to struct timeval to store stamp in
2829  *
2830  *      Timestamps are stored in the skb as offsets to a base timestamp.
2831  *      This function converts the offset back to a struct timeval and stores
2832  *      it in stamp.
2833  */
2834 static inline void skb_get_timestamp(const struct sk_buff *skb,
2835                                      struct timeval *stamp)
2836 {
2837         *stamp = ktime_to_timeval(skb->tstamp);
2838 }
2839 
2840 static inline void skb_get_timestampns(const struct sk_buff *skb,
2841                                        struct timespec *stamp)
2842 {
2843         *stamp = ktime_to_timespec(skb->tstamp);
2844 }
2845 
2846 static inline void __net_timestamp(struct sk_buff *skb)
2847 {
2848         skb->tstamp = ktime_get_real();
2849 }
2850 
2851 static inline ktime_t net_timedelta(ktime_t t)
2852 {
2853         return ktime_sub(ktime_get_real(), t);
2854 }
2855 
2856 static inline ktime_t net_invalid_timestamp(void)
2857 {
2858         return ktime_set(0, 0);
2859 }
2860 
2861 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
2862 
2863 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2864 
2865 void skb_clone_tx_timestamp(struct sk_buff *skb);
2866 bool skb_defer_rx_timestamp(struct sk_buff *skb);
2867 
2868 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2869 
2870 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2871 {
2872 }
2873 
2874 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2875 {
2876         return false;
2877 }
2878 
2879 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2880 
2881 /**
2882  * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2883  *
2884  * PHY drivers may accept clones of transmitted packets for
2885  * timestamping via their phy_driver.txtstamp method. These drivers
2886  * must call this function to return the skb back to the stack with a
2887  * timestamp.
2888  *
2889  * @skb: clone of the the original outgoing packet
2890  * @hwtstamps: hardware time stamps
2891  *
2892  */
2893 void skb_complete_tx_timestamp(struct sk_buff *skb,
2894                                struct skb_shared_hwtstamps *hwtstamps);
2895 
2896 void __skb_tstamp_tx(struct sk_buff *orig_skb,
2897                      struct skb_shared_hwtstamps *hwtstamps,
2898                      struct sock *sk, int tstype);
2899 
2900 /**
2901  * skb_tstamp_tx - queue clone of skb with send time stamps
2902  * @orig_skb:   the original outgoing packet
2903  * @hwtstamps:  hardware time stamps, may be NULL if not available
2904  *
2905  * If the skb has a socket associated, then this function clones the
2906  * skb (thus sharing the actual data and optional structures), stores
2907  * the optional hardware time stamping information (if non NULL) or
2908  * generates a software time stamp (otherwise), then queues the clone
2909  * to the error queue of the socket.  Errors are silently ignored.
2910  */
2911 void skb_tstamp_tx(struct sk_buff *orig_skb,
2912                    struct skb_shared_hwtstamps *hwtstamps);
2913 
2914 static inline void sw_tx_timestamp(struct sk_buff *skb)
2915 {
2916         if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2917             !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2918                 skb_tstamp_tx(skb, NULL);
2919 }
2920 
2921 /**
2922  * skb_tx_timestamp() - Driver hook for transmit timestamping
2923  *
2924  * Ethernet MAC Drivers should call this function in their hard_xmit()
2925  * function immediately before giving the sk_buff to the MAC hardware.
2926  *
2927  * Specifically, one should make absolutely sure that this function is
2928  * called before TX completion of this packet can trigger.  Otherwise
2929  * the packet could potentially already be freed.
2930  *
2931  * @skb: A socket buffer.
2932  */
2933 static inline void skb_tx_timestamp(struct sk_buff *skb)
2934 {
2935         skb_clone_tx_timestamp(skb);
2936         sw_tx_timestamp(skb);
2937 }
2938 
2939 /**
2940  * skb_complete_wifi_ack - deliver skb with wifi status
2941  *
2942  * @skb: the original outgoing packet
2943  * @acked: ack status
2944  *
2945  */
2946 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
2947 
2948 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2949 __sum16 __skb_checksum_complete(struct sk_buff *skb);
2950 
2951 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2952 {
2953         return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
2954                 skb->csum_valid ||
2955                 (skb->ip_summed == CHECKSUM_PARTIAL &&
2956                  skb_checksum_start_offset(skb) >= 0));
2957 }
2958 
2959 /**
2960  *      skb_checksum_complete - Calculate checksum of an entire packet
2961  *      @skb: packet to process
2962  *
2963  *      This function calculates the checksum over the entire packet plus
2964  *      the value of skb->csum.  The latter can be used to supply the
2965  *      checksum of a pseudo header as used by TCP/UDP.  It returns the
2966  *      checksum.
2967  *
2968  *      For protocols that contain complete checksums such as ICMP/TCP/UDP,
2969  *      this function can be used to verify that checksum on received
2970  *      packets.  In that case the function should return zero if the
2971  *      checksum is correct.  In particular, this function will return zero
2972  *      if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2973  *      hardware has already verified the correctness of the checksum.
2974  */
2975 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2976 {
2977         return skb_csum_unnecessary(skb) ?
2978                0 : __skb_checksum_complete(skb);
2979 }
2980 
2981 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
2982 {
2983         if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
2984                 if (skb->csum_level == 0)
2985                         skb->ip_summed = CHECKSUM_NONE;
2986                 else
2987                         skb->csum_level--;
2988         }
2989 }
2990 
2991 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
2992 {
2993         if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
2994                 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
2995                         skb->csum_level++;
2996         } else if (skb->ip_summed == CHECKSUM_NONE) {
2997                 skb->ip_summed = CHECKSUM_UNNECESSARY;
2998                 skb->csum_level = 0;
2999         }
3000 }
3001 
3002 static inline void __skb_mark_checksum_bad(struct sk_buff *skb)
3003 {
3004         /* Mark current checksum as bad (typically called from GRO
3005          * path). In the case that ip_summed is CHECKSUM_NONE
3006          * this must be the first checksum encountered in the packet.
3007          * When ip_summed is CHECKSUM_UNNECESSARY, this is the first
3008          * checksum after the last one validated. For UDP, a zero
3009          * checksum can not be marked as bad.
3010          */
3011 
3012         if (skb->ip_summed == CHECKSUM_NONE ||
3013             skb->ip_summed == CHECKSUM_UNNECESSARY)
3014                 skb->csum_bad = 1;
3015 }
3016 
3017 /* Check if we need to perform checksum complete validation.
3018  *
3019  * Returns true if checksum complete is needed, false otherwise
3020  * (either checksum is unnecessary or zero checksum is allowed).
3021  */
3022 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3023                                                   bool zero_okay,
3024                                                   __sum16 check)
3025 {
3026         if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3027                 skb->csum_valid = 1;
3028                 __skb_decr_checksum_unnecessary(skb);
3029                 return false;
3030         }
3031 
3032         return true;
3033 }
3034 
3035 /* For small packets <= CHECKSUM_BREAK peform checksum complete directly
3036  * in checksum_init.
3037  */
3038 #define CHECKSUM_BREAK 76
3039 
3040 /* Unset checksum-complete
3041  *
3042  * Unset checksum complete can be done when packet is being modified
3043  * (uncompressed for instance) and checksum-complete value is
3044  * invalidated.
3045  */
3046 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3047 {
3048         if (skb->ip_summed == CHECKSUM_COMPLETE)
3049                 skb->ip_summed = CHECKSUM_NONE;
3050 }
3051 
3052 /* Validate (init) checksum based on checksum complete.
3053  *
3054  * Return values:
3055  *   0: checksum is validated or try to in skb_checksum_complete. In the latter
3056  *      case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3057  *      checksum is stored in skb->csum for use in __skb_checksum_complete
3058  *   non-zero: value of invalid checksum
3059  *
3060  */
3061 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3062                                                        bool complete,
3063                                                        __wsum psum)
3064 {
3065         if (skb->ip_summed == CHECKSUM_COMPLETE) {
3066                 if (!csum_fold(csum_add(psum, skb->csum))) {
3067                         skb->csum_valid = 1;
3068                         return 0;
3069                 }
3070         } else if (skb->csum_bad) {
3071                 /* ip_summed == CHECKSUM_NONE in this case */
3072                 return (__force __sum16)1;
3073         }
3074 
3075         skb->csum = psum;
3076 
3077         if (complete || skb->len <= CHECKSUM_BREAK) {
3078                 __sum16 csum;
3079 
3080                 csum = __skb_checksum_complete(skb);
3081                 skb->csum_valid = !csum;
3082                 return csum;
3083         }
3084 
3085         return 0;
3086 }
3087 
3088 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3089 {
3090         return 0;
3091 }
3092 
3093 /* Perform checksum validate (init). Note that this is a macro since we only
3094  * want to calculate the pseudo header which is an input function if necessary.
3095  * First we try to validate without any computation (checksum unnecessary) and
3096  * then calculate based on checksum complete calling the function to compute
3097  * pseudo header.
3098  *
3099  * Return values:
3100  *   0: checksum is validated or try to in skb_checksum_complete
3101  *   non-zero: value of invalid checksum
3102  */
3103 #define __skb_checksum_validate(skb, proto, complete,                   \
3104                                 zero_okay, check, compute_pseudo)       \
3105 ({                                                                      \
3106         __sum16 __ret = 0;                                              \
3107         skb->csum_valid = 0;                                            \
3108         if (__skb_checksum_validate_needed(skb, zero_okay, check))      \
3109                 __ret = __skb_checksum_validate_complete(skb,           \
3110                                 complete, compute_pseudo(skb, proto));  \
3111         __ret;                                                          \
3112 })
3113 
3114 #define skb_checksum_init(skb, proto, compute_pseudo)                   \
3115         __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3116 
3117 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3118         __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3119 
3120 #define skb_checksum_validate(skb, proto, compute_pseudo)               \
3121         __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3122 
3123 #define skb_checksum_validate_zero_check(skb, proto, check,             \
3124                                          compute_pseudo)                \
3125         __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3126 
3127 #define skb_checksum_simple_validate(skb)                               \
3128         __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3129 
3130 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3131 {
3132         return (skb->ip_summed == CHECKSUM_NONE &&
3133                 skb->csum_valid && !skb->csum_bad);
3134 }
3135 
3136 static inline void __skb_checksum_convert(struct sk_buff *skb,
3137                                           __sum16 check, __wsum pseudo)
3138 {
3139         skb->csum = ~pseudo;
3140         skb->ip_summed = CHECKSUM_COMPLETE;
3141 }
3142 
3143 #define skb_checksum_try_convert(skb, proto, check, compute_pseudo)     \
3144 do {                                                                    \
3145         if (__skb_checksum_convert_check(skb))                          \
3146                 __skb_checksum_convert(skb, check,                      \
3147                                        compute_pseudo(skb, proto));     \
3148 } while (0)
3149 
3150 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3151                                               u16 start, u16 offset)
3152 {
3153         skb->ip_summed = CHECKSUM_PARTIAL;
3154         skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3155         skb->csum_offset = offset - start;
3156 }
3157 
3158 /* Update skbuf and packet to reflect the remote checksum offload operation.
3159  * When called, ptr indicates the starting point for skb->csum when
3160  * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3161  * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3162  */
3163 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3164                                        int start, int offset, bool nopartial)
3165 {
3166         __wsum delta;
3167 
3168         if (!nopartial) {
3169                 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3170                 return;
3171         }
3172 
3173          if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3174                 __skb_checksum_complete(skb);
3175                 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3176         }
3177 
3178         delta = remcsum_adjust(ptr, skb->csum, start, offset);
3179 
3180         /* Adjust skb->csum since we changed the packet */
3181         skb->csum = csum_add(skb->csum, delta);
3182 }
3183 
3184 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3185 void nf_conntrack_destroy(struct nf_conntrack *nfct);
3186 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3187 {
3188         if (nfct && atomic_dec_and_test(&nfct->use))
3189                 nf_conntrack_destroy(nfct);
3190 }
3191 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3192 {
3193         if (nfct)
3194                 atomic_inc(&nfct->use);
3195 }
3196 #endif
3197 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3198 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
3199 {
3200         if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
3201                 kfree(nf_bridge);
3202 }
3203 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
3204 {
3205         if (nf_bridge)
3206                 atomic_inc(&nf_bridge->use);
3207 }
3208 #endif /* CONFIG_BRIDGE_NETFILTER */
3209 static inline void nf_reset(struct sk_buff *skb)
3210 {
3211 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3212         nf_conntrack_put(skb->nfct);
3213         skb->nfct = NULL;
3214 #endif
3215 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3216         nf_bridge_put(skb->nf_bridge);
3217         skb->nf_bridge = NULL;
3218 #endif
3219 }
3220 
3221 static inline void nf_reset_trace(struct sk_buff *skb)
3222 {
3223 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3224         skb->nf_trace = 0;
3225 #endif
3226 }
3227 
3228 /* Note: This doesn't put any conntrack and bridge info in dst. */
3229 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
3230                              bool copy)
3231 {
3232 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3233         dst->nfct = src->nfct;
3234         nf_conntrack_get(src->nfct);
3235         if (copy)
3236                 dst->nfctinfo = src->nfctinfo;
3237 #endif
3238 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3239         dst->nf_bridge  = src->nf_bridge;
3240         nf_bridge_get(src->nf_bridge);
3241 #endif
3242 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3243         if (copy)
3244                 dst->nf_trace = src->nf_trace;
3245 #endif
3246 }
3247 
3248 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
3249 {
3250 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3251         nf_conntrack_put(dst->nfct);
3252 #endif
3253 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3254         nf_bridge_put(dst->nf_bridge);
3255 #endif
3256         __nf_copy(dst, src, true);
3257 }
3258 
3259 #ifdef CONFIG_NETWORK_SECMARK
3260 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3261 {
3262         to->secmark = from->secmark;
3263 }
3264 
3265 static inline void skb_init_secmark(struct sk_buff *skb)
3266 {
3267         skb->secmark = 0;
3268 }
3269 #else
3270 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3271 { }
3272 
3273 static inline void skb_init_secmark(struct sk_buff *skb)
3274 { }
3275 #endif
3276 
3277 static inline bool skb_irq_freeable(const struct sk_buff *skb)
3278 {
3279         return !skb->destructor &&
3280 #if IS_ENABLED(CONFIG_XFRM)
3281                 !skb->sp &&
3282 #endif
3283 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
3284                 !skb->nfct &&
3285 #endif
3286                 !skb->_skb_refdst &&
3287                 !skb_has_frag_list(skb);
3288 }
3289 
3290 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
3291 {
3292         skb->queue_mapping = queue_mapping;
3293 }
3294 
3295 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
3296 {
3297         return skb->queue_mapping;
3298 }
3299 
3300 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
3301 {
3302         to->queue_mapping = from->queue_mapping;
3303 }
3304 
3305 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
3306 {
3307         skb->queue_mapping = rx_queue + 1;
3308 }
3309 
3310 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
3311 {
3312         return skb->queue_mapping - 1;
3313 }
3314 
3315 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
3316 {
3317         return skb->queue_mapping != 0;
3318 }
3319 
3320 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
3321 {
3322 #ifdef CONFIG_XFRM
3323         return skb->sp;
3324 #else
3325         return NULL;
3326 #endif
3327 }
3328 
3329 /* Keeps track of mac header offset relative to skb->head.
3330  * It is useful for TSO of Tunneling protocol. e.g. GRE.
3331  * For non-tunnel skb it points to skb_mac_header() and for
3332  * tunnel skb it points to outer mac header.
3333  * Keeps track of level of encapsulation of network headers.
3334  */
3335 struct skb_gso_cb {
3336         int     mac_offset;
3337         int     encap_level;
3338         __u16   csum_start;
3339 };
3340 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
3341 
3342 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
3343 {
3344         return (skb_mac_header(inner_skb) - inner_skb->head) -
3345                 SKB_GSO_CB(inner_skb)->mac_offset;
3346 }
3347 
3348 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
3349 {
3350         int new_headroom, headroom;
3351         int ret;
3352 
3353         headroom = skb_headroom(skb);
3354         ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
3355         if (ret)
3356                 return ret;
3357 
3358         new_headroom = skb_headroom(skb);
3359         SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
3360         return 0;
3361 }
3362 
3363 /* Compute the checksum for a gso segment. First compute the checksum value
3364  * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
3365  * then add in skb->csum (checksum from csum_start to end of packet).
3366  * skb->csum and csum_start are then updated to reflect the checksum of the
3367  * resultant packet starting from the transport header-- the resultant checksum
3368  * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
3369  * header.
3370  */
3371 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
3372 {
3373         int plen = SKB_GSO_CB(skb)->csum_start - skb_headroom(skb) -
3374                    skb_transport_offset(skb);
3375         __wsum partial;
3376 
3377         partial = csum_partial(skb_transport_header(skb), plen, skb->csum);
3378         skb->csum = res;
3379         SKB_GSO_CB(skb)->csum_start -= plen;
3380 
3381         return csum_fold(partial);
3382 }
3383 
3384 static inline bool skb_is_gso(const struct sk_buff *skb)
3385 {
3386         return skb_shinfo(skb)->gso_size;
3387 }
3388 
3389 /* Note: Should be called only if skb_is_gso(skb) is true */
3390 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
3391 {
3392         return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
3393 }
3394 
3395 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
3396 
3397 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
3398 {
3399         /* LRO sets gso_size but not gso_type, whereas if GSO is really
3400          * wanted then gso_type will be set. */
3401         const struct skb_shared_info *shinfo = skb_shinfo(skb);
3402 
3403         if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
3404             unlikely(shinfo->gso_type == 0)) {
3405                 __skb_warn_lro_forwarding(skb);
3406                 return true;
3407         }
3408         return false;
3409 }
3410 
3411 static inline void skb_forward_csum(struct sk_buff *skb)
3412 {
3413         /* Unfortunately we don't support this one.  Any brave souls? */
3414         if (skb->ip_summed == CHECKSUM_COMPLETE)
3415                 skb->ip_summed = CHECKSUM_NONE;
3416 }
3417 
3418 /**
3419  * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
3420  * @skb: skb to check
3421  *
3422  * fresh skbs have their ip_summed set to CHECKSUM_NONE.
3423  * Instead of forcing ip_summed to CHECKSUM_NONE, we can
3424  * use this helper, to document places where we make this assertion.
3425  */
3426 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
3427 {
3428 #ifdef DEBUG
3429         BUG_ON(skb->ip_summed != CHECKSUM_NONE);
3430 #endif
3431 }
3432 
3433 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
3434 
3435 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
3436 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
3437                                      unsigned int transport_len,
3438                                      __sum16(*skb_chkf)(struct sk_buff *skb));
3439 
3440 /**
3441  * skb_head_is_locked - Determine if the skb->head is locked down
3442  * @skb: skb to check
3443  *
3444  * The head on skbs build around a head frag can be removed if they are
3445  * not cloned.  This function returns true if the skb head is locked down
3446  * due to either being allocated via kmalloc, or by being a clone with
3447  * multiple references to the head.
3448  */
3449 static inline bool skb_head_is_locked(const struct sk_buff *skb)
3450 {
3451         return !skb->head_frag || skb_cloned(skb);
3452 }
3453 
3454 /**
3455  * skb_gso_network_seglen - Return length of individual segments of a gso packet
3456  *
3457  * @skb: GSO skb
3458  *
3459  * skb_gso_network_seglen is used to determine the real size of the
3460  * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
3461  *
3462  * The MAC/L2 header is not accounted for.
3463  */
3464 static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
3465 {
3466         unsigned int hdr_len = skb_transport_header(skb) -
3467                                skb_network_header(skb);
3468         return hdr_len + skb_gso_transport_seglen(skb);
3469 }
3470 #endif  /* __KERNEL__ */
3471 #endif  /* _LINUX_SKBUFF_H */
3472 

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