Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

Linux/include/linux/skbuff.h

  1 /*
  2  *      Definitions for the 'struct sk_buff' memory handlers.
  3  *
  4  *      Authors:
  5  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  6  *              Florian La Roche, <rzsfl@rz.uni-sb.de>
  7  *
  8  *      This program is free software; you can redistribute it and/or
  9  *      modify it under the terms of the GNU General Public License
 10  *      as published by the Free Software Foundation; either version
 11  *      2 of the License, or (at your option) any later version.
 12  */
 13 
 14 #ifndef _LINUX_SKBUFF_H
 15 #define _LINUX_SKBUFF_H
 16 
 17 #include <linux/kernel.h>
 18 #include <linux/kmemcheck.h>
 19 #include <linux/compiler.h>
 20 #include <linux/time.h>
 21 #include <linux/bug.h>
 22 #include <linux/cache.h>
 23 
 24 #include <linux/atomic.h>
 25 #include <asm/types.h>
 26 #include <linux/spinlock.h>
 27 #include <linux/net.h>
 28 #include <linux/textsearch.h>
 29 #include <net/checksum.h>
 30 #include <linux/rcupdate.h>
 31 #include <linux/dmaengine.h>
 32 #include <linux/hrtimer.h>
 33 #include <linux/dma-mapping.h>
 34 #include <linux/netdev_features.h>
 35 #include <net/flow_keys.h>
 36 
 37 /* A. Checksumming of received packets by device.
 38  *
 39  * CHECKSUM_NONE:
 40  *
 41  *   Device failed to checksum this packet e.g. due to lack of capabilities.
 42  *   The packet contains full (though not verified) checksum in packet but
 43  *   not in skb->csum. Thus, skb->csum is undefined in this case.
 44  *
 45  * CHECKSUM_UNNECESSARY:
 46  *
 47  *   The hardware you're dealing with doesn't calculate the full checksum
 48  *   (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
 49  *   for specific protocols e.g. TCP/UDP/SCTP, then, for such packets it will
 50  *   set CHECKSUM_UNNECESSARY if their checksums are okay. skb->csum is still
 51  *   undefined in this case though. It is a bad option, but, unfortunately,
 52  *   nowadays most vendors do this. Apparently with the secret goal to sell
 53  *   you new devices, when you will add new protocol to your host, f.e. IPv6 8)
 54  *
 55  * CHECKSUM_COMPLETE:
 56  *
 57  *   This is the most generic way. The device supplied checksum of the _whole_
 58  *   packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
 59  *   hardware doesn't need to parse L3/L4 headers to implement this.
 60  *
 61  *   Note: Even if device supports only some protocols, but is able to produce
 62  *   skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
 63  *
 64  * CHECKSUM_PARTIAL:
 65  *
 66  *   This is identical to the case for output below. This may occur on a packet
 67  *   received directly from another Linux OS, e.g., a virtualized Linux kernel
 68  *   on the same host. The packet can be treated in the same way as
 69  *   CHECKSUM_UNNECESSARY, except that on output (i.e., forwarding) the
 70  *   checksum must be filled in by the OS or the hardware.
 71  *
 72  * B. Checksumming on output.
 73  *
 74  * CHECKSUM_NONE:
 75  *
 76  *   The skb was already checksummed by the protocol, or a checksum is not
 77  *   required.
 78  *
 79  * CHECKSUM_PARTIAL:
 80  *
 81  *   The device is required to checksum the packet as seen by hard_start_xmit()
 82  *   from skb->csum_start up to the end, and to record/write the checksum at
 83  *   offset skb->csum_start + skb->csum_offset.
 84  *
 85  *   The device must show its capabilities in dev->features, set up at device
 86  *   setup time, e.g. netdev_features.h:
 87  *
 88  *      NETIF_F_HW_CSUM - It's a clever device, it's able to checksum everything.
 89  *      NETIF_F_IP_CSUM - Device is dumb, it's able to checksum only TCP/UDP over
 90  *                        IPv4. Sigh. Vendors like this way for an unknown reason.
 91  *                        Though, see comment above about CHECKSUM_UNNECESSARY. 8)
 92  *      NETIF_F_IPV6_CSUM - About as dumb as the last one but does IPv6 instead.
 93  *      NETIF_F_...     - Well, you get the picture.
 94  *
 95  * CHECKSUM_UNNECESSARY:
 96  *
 97  *   Normally, the device will do per protocol specific checksumming. Protocol
 98  *   implementations that do not want the NIC to perform the checksum
 99  *   calculation should use this flag in their outgoing skbs.
100  *
101  *      NETIF_F_FCOE_CRC - This indicates that the device can do FCoE FC CRC
102  *                         offload. Correspondingly, the FCoE protocol driver
103  *                         stack should use CHECKSUM_UNNECESSARY.
104  *
105  * Any questions? No questions, good.           --ANK
106  */
107 
108 /* Don't change this without changing skb_csum_unnecessary! */
109 #define CHECKSUM_NONE           0
110 #define CHECKSUM_UNNECESSARY    1
111 #define CHECKSUM_COMPLETE       2
112 #define CHECKSUM_PARTIAL        3
113 
114 #define SKB_DATA_ALIGN(X)       (((X) + (SMP_CACHE_BYTES - 1)) & \
115                                  ~(SMP_CACHE_BYTES - 1))
116 #define SKB_WITH_OVERHEAD(X)    \
117         ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
118 #define SKB_MAX_ORDER(X, ORDER) \
119         SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
120 #define SKB_MAX_HEAD(X)         (SKB_MAX_ORDER((X), 0))
121 #define SKB_MAX_ALLOC           (SKB_MAX_ORDER(0, 2))
122 
123 /* return minimum truesize of one skb containing X bytes of data */
124 #define SKB_TRUESIZE(X) ((X) +                                          \
125                          SKB_DATA_ALIGN(sizeof(struct sk_buff)) +       \
126                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
127 
128 struct net_device;
129 struct scatterlist;
130 struct pipe_inode_info;
131 
132 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
133 struct nf_conntrack {
134         atomic_t use;
135 };
136 #endif
137 
138 #ifdef CONFIG_BRIDGE_NETFILTER
139 struct nf_bridge_info {
140         atomic_t                use;
141         unsigned int            mask;
142         struct net_device       *physindev;
143         struct net_device       *physoutdev;
144         unsigned long           data[32 / sizeof(unsigned long)];
145 };
146 #endif
147 
148 struct sk_buff_head {
149         /* These two members must be first. */
150         struct sk_buff  *next;
151         struct sk_buff  *prev;
152 
153         __u32           qlen;
154         spinlock_t      lock;
155 };
156 
157 struct sk_buff;
158 
159 /* To allow 64K frame to be packed as single skb without frag_list we
160  * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
161  * buffers which do not start on a page boundary.
162  *
163  * Since GRO uses frags we allocate at least 16 regardless of page
164  * size.
165  */
166 #if (65536/PAGE_SIZE + 1) < 16
167 #define MAX_SKB_FRAGS 16UL
168 #else
169 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
170 #endif
171 
172 typedef struct skb_frag_struct skb_frag_t;
173 
174 struct skb_frag_struct {
175         struct {
176                 struct page *p;
177         } page;
178 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
179         __u32 page_offset;
180         __u32 size;
181 #else
182         __u16 page_offset;
183         __u16 size;
184 #endif
185 };
186 
187 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
188 {
189         return frag->size;
190 }
191 
192 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
193 {
194         frag->size = size;
195 }
196 
197 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
198 {
199         frag->size += delta;
200 }
201 
202 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
203 {
204         frag->size -= delta;
205 }
206 
207 #define HAVE_HW_TIME_STAMP
208 
209 /**
210  * struct skb_shared_hwtstamps - hardware time stamps
211  * @hwtstamp:   hardware time stamp transformed into duration
212  *              since arbitrary point in time
213  * @syststamp:  hwtstamp transformed to system time base
214  *
215  * Software time stamps generated by ktime_get_real() are stored in
216  * skb->tstamp. The relation between the different kinds of time
217  * stamps is as follows:
218  *
219  * syststamp and tstamp can be compared against each other in
220  * arbitrary combinations.  The accuracy of a
221  * syststamp/tstamp/"syststamp from other device" comparison is
222  * limited by the accuracy of the transformation into system time
223  * base. This depends on the device driver and its underlying
224  * hardware.
225  *
226  * hwtstamps can only be compared against other hwtstamps from
227  * the same device.
228  *
229  * This structure is attached to packets as part of the
230  * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
231  */
232 struct skb_shared_hwtstamps {
233         ktime_t hwtstamp;
234         ktime_t syststamp;
235 };
236 
237 /* Definitions for tx_flags in struct skb_shared_info */
238 enum {
239         /* generate hardware time stamp */
240         SKBTX_HW_TSTAMP = 1 << 0,
241 
242         /* generate software time stamp */
243         SKBTX_SW_TSTAMP = 1 << 1,
244 
245         /* device driver is going to provide hardware time stamp */
246         SKBTX_IN_PROGRESS = 1 << 2,
247 
248         /* device driver supports TX zero-copy buffers */
249         SKBTX_DEV_ZEROCOPY = 1 << 3,
250 
251         /* generate wifi status information (where possible) */
252         SKBTX_WIFI_STATUS = 1 << 4,
253 
254         /* This indicates at least one fragment might be overwritten
255          * (as in vmsplice(), sendfile() ...)
256          * If we need to compute a TX checksum, we'll need to copy
257          * all frags to avoid possible bad checksum
258          */
259         SKBTX_SHARED_FRAG = 1 << 5,
260 };
261 
262 /*
263  * The callback notifies userspace to release buffers when skb DMA is done in
264  * lower device, the skb last reference should be 0 when calling this.
265  * The zerocopy_success argument is true if zero copy transmit occurred,
266  * false on data copy or out of memory error caused by data copy attempt.
267  * The ctx field is used to track device context.
268  * The desc field is used to track userspace buffer index.
269  */
270 struct ubuf_info {
271         void (*callback)(struct ubuf_info *, bool zerocopy_success);
272         void *ctx;
273         unsigned long desc;
274 };
275 
276 /* This data is invariant across clones and lives at
277  * the end of the header data, ie. at skb->end.
278  */
279 struct skb_shared_info {
280         unsigned char   nr_frags;
281         __u8            tx_flags;
282         unsigned short  gso_size;
283         /* Warning: this field is not always filled in (UFO)! */
284         unsigned short  gso_segs;
285         unsigned short  gso_type;
286         struct sk_buff  *frag_list;
287         struct skb_shared_hwtstamps hwtstamps;
288         __be32          ip6_frag_id;
289 
290         /*
291          * Warning : all fields before dataref are cleared in __alloc_skb()
292          */
293         atomic_t        dataref;
294 
295         /* Intermediate layers must ensure that destructor_arg
296          * remains valid until skb destructor */
297         void *          destructor_arg;
298 
299         /* must be last field, see pskb_expand_head() */
300         skb_frag_t      frags[MAX_SKB_FRAGS];
301 };
302 
303 /* We divide dataref into two halves.  The higher 16 bits hold references
304  * to the payload part of skb->data.  The lower 16 bits hold references to
305  * the entire skb->data.  A clone of a headerless skb holds the length of
306  * the header in skb->hdr_len.
307  *
308  * All users must obey the rule that the skb->data reference count must be
309  * greater than or equal to the payload reference count.
310  *
311  * Holding a reference to the payload part means that the user does not
312  * care about modifications to the header part of skb->data.
313  */
314 #define SKB_DATAREF_SHIFT 16
315 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
316 
317 
318 enum {
319         SKB_FCLONE_UNAVAILABLE,
320         SKB_FCLONE_ORIG,
321         SKB_FCLONE_CLONE,
322 };
323 
324 enum {
325         SKB_GSO_TCPV4 = 1 << 0,
326         SKB_GSO_UDP = 1 << 1,
327 
328         /* This indicates the skb is from an untrusted source. */
329         SKB_GSO_DODGY = 1 << 2,
330 
331         /* This indicates the tcp segment has CWR set. */
332         SKB_GSO_TCP_ECN = 1 << 3,
333 
334         SKB_GSO_TCPV6 = 1 << 4,
335 
336         SKB_GSO_FCOE = 1 << 5,
337 
338         SKB_GSO_GRE = 1 << 6,
339 
340         SKB_GSO_IPIP = 1 << 7,
341 
342         SKB_GSO_SIT = 1 << 8,
343 
344         SKB_GSO_UDP_TUNNEL = 1 << 9,
345 
346         SKB_GSO_MPLS = 1 << 10,
347 };
348 
349 #if BITS_PER_LONG > 32
350 #define NET_SKBUFF_DATA_USES_OFFSET 1
351 #endif
352 
353 #ifdef NET_SKBUFF_DATA_USES_OFFSET
354 typedef unsigned int sk_buff_data_t;
355 #else
356 typedef unsigned char *sk_buff_data_t;
357 #endif
358 
359 /** 
360  *      struct sk_buff - socket buffer
361  *      @next: Next buffer in list
362  *      @prev: Previous buffer in list
363  *      @tstamp: Time we arrived
364  *      @sk: Socket we are owned by
365  *      @dev: Device we arrived on/are leaving by
366  *      @cb: Control buffer. Free for use by every layer. Put private vars here
367  *      @_skb_refdst: destination entry (with norefcount bit)
368  *      @sp: the security path, used for xfrm
369  *      @len: Length of actual data
370  *      @data_len: Data length
371  *      @mac_len: Length of link layer header
372  *      @hdr_len: writable header length of cloned skb
373  *      @csum: Checksum (must include start/offset pair)
374  *      @csum_start: Offset from skb->head where checksumming should start
375  *      @csum_offset: Offset from csum_start where checksum should be stored
376  *      @priority: Packet queueing priority
377  *      @local_df: allow local fragmentation
378  *      @cloned: Head may be cloned (check refcnt to be sure)
379  *      @ip_summed: Driver fed us an IP checksum
380  *      @nohdr: Payload reference only, must not modify header
381  *      @nfctinfo: Relationship of this skb to the connection
382  *      @pkt_type: Packet class
383  *      @fclone: skbuff clone status
384  *      @ipvs_property: skbuff is owned by ipvs
385  *      @peeked: this packet has been seen already, so stats have been
386  *              done for it, don't do them again
387  *      @nf_trace: netfilter packet trace flag
388  *      @protocol: Packet protocol from driver
389  *      @destructor: Destruct function
390  *      @nfct: Associated connection, if any
391  *      @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
392  *      @skb_iif: ifindex of device we arrived on
393  *      @tc_index: Traffic control index
394  *      @tc_verd: traffic control verdict
395  *      @rxhash: the packet hash computed on receive
396  *      @queue_mapping: Queue mapping for multiqueue devices
397  *      @ndisc_nodetype: router type (from link layer)
398  *      @ooo_okay: allow the mapping of a socket to a queue to be changed
399  *      @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
400  *              ports.
401  *      @wifi_acked_valid: wifi_acked was set
402  *      @wifi_acked: whether frame was acked on wifi or not
403  *      @no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
404  *      @dma_cookie: a cookie to one of several possible DMA operations
405  *              done by skb DMA functions
406   *     @napi_id: id of the NAPI struct this skb came from
407  *      @secmark: security marking
408  *      @mark: Generic packet mark
409  *      @dropcount: total number of sk_receive_queue overflows
410  *      @vlan_proto: vlan encapsulation protocol
411  *      @vlan_tci: vlan tag control information
412  *      @inner_protocol: Protocol (encapsulation)
413  *      @inner_transport_header: Inner transport layer header (encapsulation)
414  *      @inner_network_header: Network layer header (encapsulation)
415  *      @inner_mac_header: Link layer header (encapsulation)
416  *      @transport_header: Transport layer header
417  *      @network_header: Network layer header
418  *      @mac_header: Link layer header
419  *      @tail: Tail pointer
420  *      @end: End pointer
421  *      @head: Head of buffer
422  *      @data: Data head pointer
423  *      @truesize: Buffer size
424  *      @users: User count - see {datagram,tcp}.c
425  */
426 
427 struct sk_buff {
428         /* These two members must be first. */
429         struct sk_buff          *next;
430         struct sk_buff          *prev;
431 
432         ktime_t                 tstamp;
433 
434         struct sock             *sk;
435         struct net_device       *dev;
436 
437         /*
438          * This is the control buffer. It is free to use for every
439          * layer. Please put your private variables there. If you
440          * want to keep them across layers you have to do a skb_clone()
441          * first. This is owned by whoever has the skb queued ATM.
442          */
443         char                    cb[48] __aligned(8);
444 
445         unsigned long           _skb_refdst;
446 #ifdef CONFIG_XFRM
447         struct  sec_path        *sp;
448 #endif
449         unsigned int            len,
450                                 data_len;
451         __u16                   mac_len,
452                                 hdr_len;
453         union {
454                 __wsum          csum;
455                 struct {
456                         __u16   csum_start;
457                         __u16   csum_offset;
458                 };
459         };
460         __u32                   priority;
461         kmemcheck_bitfield_begin(flags1);
462         __u8                    local_df:1,
463                                 cloned:1,
464                                 ip_summed:2,
465                                 nohdr:1,
466                                 nfctinfo:3;
467         __u8                    pkt_type:3,
468                                 fclone:2,
469                                 ipvs_property:1,
470                                 peeked:1,
471                                 nf_trace:1;
472         kmemcheck_bitfield_end(flags1);
473         __be16                  protocol;
474 
475         void                    (*destructor)(struct sk_buff *skb);
476 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
477         struct nf_conntrack     *nfct;
478 #endif
479 #ifdef CONFIG_BRIDGE_NETFILTER
480         struct nf_bridge_info   *nf_bridge;
481 #endif
482 
483         int                     skb_iif;
484 
485         __u32                   rxhash;
486 
487         __be16                  vlan_proto;
488         __u16                   vlan_tci;
489 
490 #ifdef CONFIG_NET_SCHED
491         __u16                   tc_index;       /* traffic control index */
492 #ifdef CONFIG_NET_CLS_ACT
493         __u16                   tc_verd;        /* traffic control verdict */
494 #endif
495 #endif
496 
497         __u16                   queue_mapping;
498         kmemcheck_bitfield_begin(flags2);
499 #ifdef CONFIG_IPV6_NDISC_NODETYPE
500         __u8                    ndisc_nodetype:2;
501 #endif
502         __u8                    pfmemalloc:1;
503         __u8                    ooo_okay:1;
504         __u8                    l4_rxhash:1;
505         __u8                    wifi_acked_valid:1;
506         __u8                    wifi_acked:1;
507         __u8                    no_fcs:1;
508         __u8                    head_frag:1;
509         /* Encapsulation protocol and NIC drivers should use
510          * this flag to indicate to each other if the skb contains
511          * encapsulated packet or not and maybe use the inner packet
512          * headers if needed
513          */
514         __u8                    encapsulation:1;
515         /* 6/8 bit hole (depending on ndisc_nodetype presence) */
516         kmemcheck_bitfield_end(flags2);
517 
518 #if defined CONFIG_NET_DMA || defined CONFIG_NET_RX_BUSY_POLL
519         union {
520                 unsigned int    napi_id;
521                 dma_cookie_t    dma_cookie;
522         };
523 #endif
524 #ifdef CONFIG_NETWORK_SECMARK
525         __u32                   secmark;
526 #endif
527         union {
528                 __u32           mark;
529                 __u32           dropcount;
530                 __u32           reserved_tailroom;
531         };
532 
533         __be16                  inner_protocol;
534         __u16                   inner_transport_header;
535         __u16                   inner_network_header;
536         __u16                   inner_mac_header;
537         __u16                   transport_header;
538         __u16                   network_header;
539         __u16                   mac_header;
540         /* These elements must be at the end, see alloc_skb() for details.  */
541         sk_buff_data_t          tail;
542         sk_buff_data_t          end;
543         unsigned char           *head,
544                                 *data;
545         unsigned int            truesize;
546         atomic_t                users;
547 };
548 
549 #ifdef __KERNEL__
550 /*
551  *      Handling routines are only of interest to the kernel
552  */
553 #include <linux/slab.h>
554 
555 
556 #define SKB_ALLOC_FCLONE        0x01
557 #define SKB_ALLOC_RX            0x02
558 
559 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
560 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
561 {
562         return unlikely(skb->pfmemalloc);
563 }
564 
565 /*
566  * skb might have a dst pointer attached, refcounted or not.
567  * _skb_refdst low order bit is set if refcount was _not_ taken
568  */
569 #define SKB_DST_NOREF   1UL
570 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
571 
572 /**
573  * skb_dst - returns skb dst_entry
574  * @skb: buffer
575  *
576  * Returns skb dst_entry, regardless of reference taken or not.
577  */
578 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
579 {
580         /* If refdst was not refcounted, check we still are in a 
581          * rcu_read_lock section
582          */
583         WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
584                 !rcu_read_lock_held() &&
585                 !rcu_read_lock_bh_held());
586         return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
587 }
588 
589 /**
590  * skb_dst_set - sets skb dst
591  * @skb: buffer
592  * @dst: dst entry
593  *
594  * Sets skb dst, assuming a reference was taken on dst and should
595  * be released by skb_dst_drop()
596  */
597 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
598 {
599         skb->_skb_refdst = (unsigned long)dst;
600 }
601 
602 void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst,
603                          bool force);
604 
605 /**
606  * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
607  * @skb: buffer
608  * @dst: dst entry
609  *
610  * Sets skb dst, assuming a reference was not taken on dst.
611  * If dst entry is cached, we do not take reference and dst_release
612  * will be avoided by refdst_drop. If dst entry is not cached, we take
613  * reference, so that last dst_release can destroy the dst immediately.
614  */
615 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
616 {
617         __skb_dst_set_noref(skb, dst, false);
618 }
619 
620 /**
621  * skb_dst_set_noref_force - sets skb dst, without taking reference
622  * @skb: buffer
623  * @dst: dst entry
624  *
625  * Sets skb dst, assuming a reference was not taken on dst.
626  * No reference is taken and no dst_release will be called. While for
627  * cached dsts deferred reclaim is a basic feature, for entries that are
628  * not cached it is caller's job to guarantee that last dst_release for
629  * provided dst happens when nobody uses it, eg. after a RCU grace period.
630  */
631 static inline void skb_dst_set_noref_force(struct sk_buff *skb,
632                                            struct dst_entry *dst)
633 {
634         __skb_dst_set_noref(skb, dst, true);
635 }
636 
637 /**
638  * skb_dst_is_noref - Test if skb dst isn't refcounted
639  * @skb: buffer
640  */
641 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
642 {
643         return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
644 }
645 
646 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
647 {
648         return (struct rtable *)skb_dst(skb);
649 }
650 
651 void kfree_skb(struct sk_buff *skb);
652 void kfree_skb_list(struct sk_buff *segs);
653 void skb_tx_error(struct sk_buff *skb);
654 void consume_skb(struct sk_buff *skb);
655 void  __kfree_skb(struct sk_buff *skb);
656 extern struct kmem_cache *skbuff_head_cache;
657 
658 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
659 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
660                       bool *fragstolen, int *delta_truesize);
661 
662 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
663                             int node);
664 struct sk_buff *build_skb(void *data, unsigned int frag_size);
665 static inline struct sk_buff *alloc_skb(unsigned int size,
666                                         gfp_t priority)
667 {
668         return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
669 }
670 
671 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
672                                                gfp_t priority)
673 {
674         return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
675 }
676 
677 struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
678 static inline struct sk_buff *alloc_skb_head(gfp_t priority)
679 {
680         return __alloc_skb_head(priority, -1);
681 }
682 
683 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
684 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
685 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
686 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
687 struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask);
688 
689 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
690 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
691                                      unsigned int headroom);
692 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
693                                 int newtailroom, gfp_t priority);
694 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
695                  int len);
696 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
697 int skb_pad(struct sk_buff *skb, int pad);
698 #define dev_kfree_skb(a)        consume_skb(a)
699 
700 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
701                             int getfrag(void *from, char *to, int offset,
702                                         int len, int odd, struct sk_buff *skb),
703                             void *from, int length);
704 
705 struct skb_seq_state {
706         __u32           lower_offset;
707         __u32           upper_offset;
708         __u32           frag_idx;
709         __u32           stepped_offset;
710         struct sk_buff  *root_skb;
711         struct sk_buff  *cur_skb;
712         __u8            *frag_data;
713 };
714 
715 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
716                           unsigned int to, struct skb_seq_state *st);
717 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
718                           struct skb_seq_state *st);
719 void skb_abort_seq_read(struct skb_seq_state *st);
720 
721 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
722                            unsigned int to, struct ts_config *config,
723                            struct ts_state *state);
724 
725 /*
726  * Packet hash types specify the type of hash in skb_set_hash.
727  *
728  * Hash types refer to the protocol layer addresses which are used to
729  * construct a packet's hash. The hashes are used to differentiate or identify
730  * flows of the protocol layer for the hash type. Hash types are either
731  * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
732  *
733  * Properties of hashes:
734  *
735  * 1) Two packets in different flows have different hash values
736  * 2) Two packets in the same flow should have the same hash value
737  *
738  * A hash at a higher layer is considered to be more specific. A driver should
739  * set the most specific hash possible.
740  *
741  * A driver cannot indicate a more specific hash than the layer at which a hash
742  * was computed. For instance an L3 hash cannot be set as an L4 hash.
743  *
744  * A driver may indicate a hash level which is less specific than the
745  * actual layer the hash was computed on. For instance, a hash computed
746  * at L4 may be considered an L3 hash. This should only be done if the
747  * driver can't unambiguously determine that the HW computed the hash at
748  * the higher layer. Note that the "should" in the second property above
749  * permits this.
750  */
751 enum pkt_hash_types {
752         PKT_HASH_TYPE_NONE,     /* Undefined type */
753         PKT_HASH_TYPE_L2,       /* Input: src_MAC, dest_MAC */
754         PKT_HASH_TYPE_L3,       /* Input: src_IP, dst_IP */
755         PKT_HASH_TYPE_L4,       /* Input: src_IP, dst_IP, src_port, dst_port */
756 };
757 
758 static inline void
759 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
760 {
761         skb->l4_rxhash = (type == PKT_HASH_TYPE_L4);
762         skb->rxhash = hash;
763 }
764 
765 void __skb_get_hash(struct sk_buff *skb);
766 static inline __u32 skb_get_hash(struct sk_buff *skb)
767 {
768         if (!skb->l4_rxhash)
769                 __skb_get_hash(skb);
770 
771         return skb->rxhash;
772 }
773 
774 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
775 {
776         return skb->rxhash;
777 }
778 
779 static inline void skb_clear_hash(struct sk_buff *skb)
780 {
781         skb->rxhash = 0;
782         skb->l4_rxhash = 0;
783 }
784 
785 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
786 {
787         if (!skb->l4_rxhash)
788                 skb_clear_hash(skb);
789 }
790 
791 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
792 {
793         to->rxhash = from->rxhash;
794         to->l4_rxhash = from->l4_rxhash;
795 };
796 
797 #ifdef NET_SKBUFF_DATA_USES_OFFSET
798 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
799 {
800         return skb->head + skb->end;
801 }
802 
803 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
804 {
805         return skb->end;
806 }
807 #else
808 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
809 {
810         return skb->end;
811 }
812 
813 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
814 {
815         return skb->end - skb->head;
816 }
817 #endif
818 
819 /* Internal */
820 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
821 
822 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
823 {
824         return &skb_shinfo(skb)->hwtstamps;
825 }
826 
827 /**
828  *      skb_queue_empty - check if a queue is empty
829  *      @list: queue head
830  *
831  *      Returns true if the queue is empty, false otherwise.
832  */
833 static inline int skb_queue_empty(const struct sk_buff_head *list)
834 {
835         return list->next == (const struct sk_buff *) list;
836 }
837 
838 /**
839  *      skb_queue_is_last - check if skb is the last entry in the queue
840  *      @list: queue head
841  *      @skb: buffer
842  *
843  *      Returns true if @skb is the last buffer on the list.
844  */
845 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
846                                      const struct sk_buff *skb)
847 {
848         return skb->next == (const struct sk_buff *) list;
849 }
850 
851 /**
852  *      skb_queue_is_first - check if skb is the first entry in the queue
853  *      @list: queue head
854  *      @skb: buffer
855  *
856  *      Returns true if @skb is the first buffer on the list.
857  */
858 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
859                                       const struct sk_buff *skb)
860 {
861         return skb->prev == (const struct sk_buff *) list;
862 }
863 
864 /**
865  *      skb_queue_next - return the next packet in the queue
866  *      @list: queue head
867  *      @skb: current buffer
868  *
869  *      Return the next packet in @list after @skb.  It is only valid to
870  *      call this if skb_queue_is_last() evaluates to false.
871  */
872 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
873                                              const struct sk_buff *skb)
874 {
875         /* This BUG_ON may seem severe, but if we just return then we
876          * are going to dereference garbage.
877          */
878         BUG_ON(skb_queue_is_last(list, skb));
879         return skb->next;
880 }
881 
882 /**
883  *      skb_queue_prev - return the prev packet in the queue
884  *      @list: queue head
885  *      @skb: current buffer
886  *
887  *      Return the prev packet in @list before @skb.  It is only valid to
888  *      call this if skb_queue_is_first() evaluates to false.
889  */
890 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
891                                              const struct sk_buff *skb)
892 {
893         /* This BUG_ON may seem severe, but if we just return then we
894          * are going to dereference garbage.
895          */
896         BUG_ON(skb_queue_is_first(list, skb));
897         return skb->prev;
898 }
899 
900 /**
901  *      skb_get - reference buffer
902  *      @skb: buffer to reference
903  *
904  *      Makes another reference to a socket buffer and returns a pointer
905  *      to the buffer.
906  */
907 static inline struct sk_buff *skb_get(struct sk_buff *skb)
908 {
909         atomic_inc(&skb->users);
910         return skb;
911 }
912 
913 /*
914  * If users == 1, we are the only owner and are can avoid redundant
915  * atomic change.
916  */
917 
918 /**
919  *      skb_cloned - is the buffer a clone
920  *      @skb: buffer to check
921  *
922  *      Returns true if the buffer was generated with skb_clone() and is
923  *      one of multiple shared copies of the buffer. Cloned buffers are
924  *      shared data so must not be written to under normal circumstances.
925  */
926 static inline int skb_cloned(const struct sk_buff *skb)
927 {
928         return skb->cloned &&
929                (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
930 }
931 
932 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
933 {
934         might_sleep_if(pri & __GFP_WAIT);
935 
936         if (skb_cloned(skb))
937                 return pskb_expand_head(skb, 0, 0, pri);
938 
939         return 0;
940 }
941 
942 /**
943  *      skb_header_cloned - is the header a clone
944  *      @skb: buffer to check
945  *
946  *      Returns true if modifying the header part of the buffer requires
947  *      the data to be copied.
948  */
949 static inline int skb_header_cloned(const struct sk_buff *skb)
950 {
951         int dataref;
952 
953         if (!skb->cloned)
954                 return 0;
955 
956         dataref = atomic_read(&skb_shinfo(skb)->dataref);
957         dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
958         return dataref != 1;
959 }
960 
961 /**
962  *      skb_header_release - release reference to header
963  *      @skb: buffer to operate on
964  *
965  *      Drop a reference to the header part of the buffer.  This is done
966  *      by acquiring a payload reference.  You must not read from the header
967  *      part of skb->data after this.
968  */
969 static inline void skb_header_release(struct sk_buff *skb)
970 {
971         BUG_ON(skb->nohdr);
972         skb->nohdr = 1;
973         atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
974 }
975 
976 /**
977  *      skb_shared - is the buffer shared
978  *      @skb: buffer to check
979  *
980  *      Returns true if more than one person has a reference to this
981  *      buffer.
982  */
983 static inline int skb_shared(const struct sk_buff *skb)
984 {
985         return atomic_read(&skb->users) != 1;
986 }
987 
988 /**
989  *      skb_share_check - check if buffer is shared and if so clone it
990  *      @skb: buffer to check
991  *      @pri: priority for memory allocation
992  *
993  *      If the buffer is shared the buffer is cloned and the old copy
994  *      drops a reference. A new clone with a single reference is returned.
995  *      If the buffer is not shared the original buffer is returned. When
996  *      being called from interrupt status or with spinlocks held pri must
997  *      be GFP_ATOMIC.
998  *
999  *      NULL is returned on a memory allocation failure.
1000  */
1001 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1002 {
1003         might_sleep_if(pri & __GFP_WAIT);
1004         if (skb_shared(skb)) {
1005                 struct sk_buff *nskb = skb_clone(skb, pri);
1006 
1007                 if (likely(nskb))
1008                         consume_skb(skb);
1009                 else
1010                         kfree_skb(skb);
1011                 skb = nskb;
1012         }
1013         return skb;
1014 }
1015 
1016 /*
1017  *      Copy shared buffers into a new sk_buff. We effectively do COW on
1018  *      packets to handle cases where we have a local reader and forward
1019  *      and a couple of other messy ones. The normal one is tcpdumping
1020  *      a packet thats being forwarded.
1021  */
1022 
1023 /**
1024  *      skb_unshare - make a copy of a shared buffer
1025  *      @skb: buffer to check
1026  *      @pri: priority for memory allocation
1027  *
1028  *      If the socket buffer is a clone then this function creates a new
1029  *      copy of the data, drops a reference count on the old copy and returns
1030  *      the new copy with the reference count at 1. If the buffer is not a clone
1031  *      the original buffer is returned. When called with a spinlock held or
1032  *      from interrupt state @pri must be %GFP_ATOMIC
1033  *
1034  *      %NULL is returned on a memory allocation failure.
1035  */
1036 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1037                                           gfp_t pri)
1038 {
1039         might_sleep_if(pri & __GFP_WAIT);
1040         if (skb_cloned(skb)) {
1041                 struct sk_buff *nskb = skb_copy(skb, pri);
1042                 kfree_skb(skb); /* Free our shared copy */
1043                 skb = nskb;
1044         }
1045         return skb;
1046 }
1047 
1048 /**
1049  *      skb_peek - peek at the head of an &sk_buff_head
1050  *      @list_: list to peek at
1051  *
1052  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1053  *      be careful with this one. A peek leaves the buffer on the
1054  *      list and someone else may run off with it. You must hold
1055  *      the appropriate locks or have a private queue to do this.
1056  *
1057  *      Returns %NULL for an empty list or a pointer to the head element.
1058  *      The reference count is not incremented and the reference is therefore
1059  *      volatile. Use with caution.
1060  */
1061 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1062 {
1063         struct sk_buff *skb = list_->next;
1064 
1065         if (skb == (struct sk_buff *)list_)
1066                 skb = NULL;
1067         return skb;
1068 }
1069 
1070 /**
1071  *      skb_peek_next - peek skb following the given one from a queue
1072  *      @skb: skb to start from
1073  *      @list_: list to peek at
1074  *
1075  *      Returns %NULL when the end of the list is met or a pointer to the
1076  *      next element. The reference count is not incremented and the
1077  *      reference is therefore volatile. Use with caution.
1078  */
1079 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1080                 const struct sk_buff_head *list_)
1081 {
1082         struct sk_buff *next = skb->next;
1083 
1084         if (next == (struct sk_buff *)list_)
1085                 next = NULL;
1086         return next;
1087 }
1088 
1089 /**
1090  *      skb_peek_tail - peek at the tail of an &sk_buff_head
1091  *      @list_: list to peek at
1092  *
1093  *      Peek an &sk_buff. Unlike most other operations you _MUST_
1094  *      be careful with this one. A peek leaves the buffer on the
1095  *      list and someone else may run off with it. You must hold
1096  *      the appropriate locks or have a private queue to do this.
1097  *
1098  *      Returns %NULL for an empty list or a pointer to the tail element.
1099  *      The reference count is not incremented and the reference is therefore
1100  *      volatile. Use with caution.
1101  */
1102 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1103 {
1104         struct sk_buff *skb = list_->prev;
1105 
1106         if (skb == (struct sk_buff *)list_)
1107                 skb = NULL;
1108         return skb;
1109 
1110 }
1111 
1112 /**
1113  *      skb_queue_len   - get queue length
1114  *      @list_: list to measure
1115  *
1116  *      Return the length of an &sk_buff queue.
1117  */
1118 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1119 {
1120         return list_->qlen;
1121 }
1122 
1123 /**
1124  *      __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1125  *      @list: queue to initialize
1126  *
1127  *      This initializes only the list and queue length aspects of
1128  *      an sk_buff_head object.  This allows to initialize the list
1129  *      aspects of an sk_buff_head without reinitializing things like
1130  *      the spinlock.  It can also be used for on-stack sk_buff_head
1131  *      objects where the spinlock is known to not be used.
1132  */
1133 static inline void __skb_queue_head_init(struct sk_buff_head *list)
1134 {
1135         list->prev = list->next = (struct sk_buff *)list;
1136         list->qlen = 0;
1137 }
1138 
1139 /*
1140  * This function creates a split out lock class for each invocation;
1141  * this is needed for now since a whole lot of users of the skb-queue
1142  * infrastructure in drivers have different locking usage (in hardirq)
1143  * than the networking core (in softirq only). In the long run either the
1144  * network layer or drivers should need annotation to consolidate the
1145  * main types of usage into 3 classes.
1146  */
1147 static inline void skb_queue_head_init(struct sk_buff_head *list)
1148 {
1149         spin_lock_init(&list->lock);
1150         __skb_queue_head_init(list);
1151 }
1152 
1153 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1154                 struct lock_class_key *class)
1155 {
1156         skb_queue_head_init(list);
1157         lockdep_set_class(&list->lock, class);
1158 }
1159 
1160 /*
1161  *      Insert an sk_buff on a list.
1162  *
1163  *      The "__skb_xxxx()" functions are the non-atomic ones that
1164  *      can only be called with interrupts disabled.
1165  */
1166 void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
1167                 struct sk_buff_head *list);
1168 static inline void __skb_insert(struct sk_buff *newsk,
1169                                 struct sk_buff *prev, struct sk_buff *next,
1170                                 struct sk_buff_head *list)
1171 {
1172         newsk->next = next;
1173         newsk->prev = prev;
1174         next->prev  = prev->next = newsk;
1175         list->qlen++;
1176 }
1177 
1178 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1179                                       struct sk_buff *prev,
1180                                       struct sk_buff *next)
1181 {
1182         struct sk_buff *first = list->next;
1183         struct sk_buff *last = list->prev;
1184 
1185         first->prev = prev;
1186         prev->next = first;
1187 
1188         last->next = next;
1189         next->prev = last;
1190 }
1191 
1192 /**
1193  *      skb_queue_splice - join two skb lists, this is designed for stacks
1194  *      @list: the new list to add
1195  *      @head: the place to add it in the first list
1196  */
1197 static inline void skb_queue_splice(const struct sk_buff_head *list,
1198                                     struct sk_buff_head *head)
1199 {
1200         if (!skb_queue_empty(list)) {
1201                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1202                 head->qlen += list->qlen;
1203         }
1204 }
1205 
1206 /**
1207  *      skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1208  *      @list: the new list to add
1209  *      @head: the place to add it in the first list
1210  *
1211  *      The list at @list is reinitialised
1212  */
1213 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1214                                          struct sk_buff_head *head)
1215 {
1216         if (!skb_queue_empty(list)) {
1217                 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1218                 head->qlen += list->qlen;
1219                 __skb_queue_head_init(list);
1220         }
1221 }
1222 
1223 /**
1224  *      skb_queue_splice_tail - join two skb lists, each list being a queue
1225  *      @list: the new list to add
1226  *      @head: the place to add it in the first list
1227  */
1228 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1229                                          struct sk_buff_head *head)
1230 {
1231         if (!skb_queue_empty(list)) {
1232                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1233                 head->qlen += list->qlen;
1234         }
1235 }
1236 
1237 /**
1238  *      skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1239  *      @list: the new list to add
1240  *      @head: the place to add it in the first list
1241  *
1242  *      Each of the lists is a queue.
1243  *      The list at @list is reinitialised
1244  */
1245 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1246                                               struct sk_buff_head *head)
1247 {
1248         if (!skb_queue_empty(list)) {
1249                 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1250                 head->qlen += list->qlen;
1251                 __skb_queue_head_init(list);
1252         }
1253 }
1254 
1255 /**
1256  *      __skb_queue_after - queue a buffer at the list head
1257  *      @list: list to use
1258  *      @prev: place after this buffer
1259  *      @newsk: buffer to queue
1260  *
1261  *      Queue a buffer int the middle of a list. This function takes no locks
1262  *      and you must therefore hold required locks before calling it.
1263  *
1264  *      A buffer cannot be placed on two lists at the same time.
1265  */
1266 static inline void __skb_queue_after(struct sk_buff_head *list,
1267                                      struct sk_buff *prev,
1268                                      struct sk_buff *newsk)
1269 {
1270         __skb_insert(newsk, prev, prev->next, list);
1271 }
1272 
1273 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1274                 struct sk_buff_head *list);
1275 
1276 static inline void __skb_queue_before(struct sk_buff_head *list,
1277                                       struct sk_buff *next,
1278                                       struct sk_buff *newsk)
1279 {
1280         __skb_insert(newsk, next->prev, next, list);
1281 }
1282 
1283 /**
1284  *      __skb_queue_head - queue a buffer at the list head
1285  *      @list: list to use
1286  *      @newsk: buffer to queue
1287  *
1288  *      Queue a buffer at the start of a list. This function takes no locks
1289  *      and you must therefore hold required locks before calling it.
1290  *
1291  *      A buffer cannot be placed on two lists at the same time.
1292  */
1293 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1294 static inline void __skb_queue_head(struct sk_buff_head *list,
1295                                     struct sk_buff *newsk)
1296 {
1297         __skb_queue_after(list, (struct sk_buff *)list, newsk);
1298 }
1299 
1300 /**
1301  *      __skb_queue_tail - queue a buffer at the list tail
1302  *      @list: list to use
1303  *      @newsk: buffer to queue
1304  *
1305  *      Queue a buffer at the end of a list. This function takes no locks
1306  *      and you must therefore hold required locks before calling it.
1307  *
1308  *      A buffer cannot be placed on two lists at the same time.
1309  */
1310 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1311 static inline void __skb_queue_tail(struct sk_buff_head *list,
1312                                    struct sk_buff *newsk)
1313 {
1314         __skb_queue_before(list, (struct sk_buff *)list, newsk);
1315 }
1316 
1317 /*
1318  * remove sk_buff from list. _Must_ be called atomically, and with
1319  * the list known..
1320  */
1321 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1322 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1323 {
1324         struct sk_buff *next, *prev;
1325 
1326         list->qlen--;
1327         next       = skb->next;
1328         prev       = skb->prev;
1329         skb->next  = skb->prev = NULL;
1330         next->prev = prev;
1331         prev->next = next;
1332 }
1333 
1334 /**
1335  *      __skb_dequeue - remove from the head of the queue
1336  *      @list: list to dequeue from
1337  *
1338  *      Remove the head of the list. This function does not take any locks
1339  *      so must be used with appropriate locks held only. The head item is
1340  *      returned or %NULL if the list is empty.
1341  */
1342 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1343 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1344 {
1345         struct sk_buff *skb = skb_peek(list);
1346         if (skb)
1347                 __skb_unlink(skb, list);
1348         return skb;
1349 }
1350 
1351 /**
1352  *      __skb_dequeue_tail - remove from the tail of the queue
1353  *      @list: list to dequeue from
1354  *
1355  *      Remove the tail of the list. This function does not take any locks
1356  *      so must be used with appropriate locks held only. The tail item is
1357  *      returned or %NULL if the list is empty.
1358  */
1359 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1360 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1361 {
1362         struct sk_buff *skb = skb_peek_tail(list);
1363         if (skb)
1364                 __skb_unlink(skb, list);
1365         return skb;
1366 }
1367 
1368 
1369 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1370 {
1371         return skb->data_len;
1372 }
1373 
1374 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1375 {
1376         return skb->len - skb->data_len;
1377 }
1378 
1379 static inline int skb_pagelen(const struct sk_buff *skb)
1380 {
1381         int i, len = 0;
1382 
1383         for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1384                 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1385         return len + skb_headlen(skb);
1386 }
1387 
1388 /**
1389  * __skb_fill_page_desc - initialise a paged fragment in an skb
1390  * @skb: buffer containing fragment to be initialised
1391  * @i: paged fragment index to initialise
1392  * @page: the page to use for this fragment
1393  * @off: the offset to the data with @page
1394  * @size: the length of the data
1395  *
1396  * Initialises the @i'th fragment of @skb to point to &size bytes at
1397  * offset @off within @page.
1398  *
1399  * Does not take any additional reference on the fragment.
1400  */
1401 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1402                                         struct page *page, int off, int size)
1403 {
1404         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1405 
1406         /*
1407          * Propagate page->pfmemalloc to the skb if we can. The problem is
1408          * that not all callers have unique ownership of the page. If
1409          * pfmemalloc is set, we check the mapping as a mapping implies
1410          * page->index is set (index and pfmemalloc share space).
1411          * If it's a valid mapping, we cannot use page->pfmemalloc but we
1412          * do not lose pfmemalloc information as the pages would not be
1413          * allocated using __GFP_MEMALLOC.
1414          */
1415         frag->page.p              = page;
1416         frag->page_offset         = off;
1417         skb_frag_size_set(frag, size);
1418 
1419         page = compound_head(page);
1420         if (page->pfmemalloc && !page->mapping)
1421                 skb->pfmemalloc = true;
1422 }
1423 
1424 /**
1425  * skb_fill_page_desc - initialise a paged fragment in an skb
1426  * @skb: buffer containing fragment to be initialised
1427  * @i: paged fragment index to initialise
1428  * @page: the page to use for this fragment
1429  * @off: the offset to the data with @page
1430  * @size: the length of the data
1431  *
1432  * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1433  * @skb to point to @size bytes at offset @off within @page. In
1434  * addition updates @skb such that @i is the last fragment.
1435  *
1436  * Does not take any additional reference on the fragment.
1437  */
1438 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1439                                       struct page *page, int off, int size)
1440 {
1441         __skb_fill_page_desc(skb, i, page, off, size);
1442         skb_shinfo(skb)->nr_frags = i + 1;
1443 }
1444 
1445 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
1446                      int size, unsigned int truesize);
1447 
1448 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
1449                           unsigned int truesize);
1450 
1451 #define SKB_PAGE_ASSERT(skb)    BUG_ON(skb_shinfo(skb)->nr_frags)
1452 #define SKB_FRAG_ASSERT(skb)    BUG_ON(skb_has_frag_list(skb))
1453 #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
1454 
1455 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1456 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1457 {
1458         return skb->head + skb->tail;
1459 }
1460 
1461 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1462 {
1463         skb->tail = skb->data - skb->head;
1464 }
1465 
1466 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1467 {
1468         skb_reset_tail_pointer(skb);
1469         skb->tail += offset;
1470 }
1471 
1472 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1473 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1474 {
1475         return skb->tail;
1476 }
1477 
1478 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1479 {
1480         skb->tail = skb->data;
1481 }
1482 
1483 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1484 {
1485         skb->tail = skb->data + offset;
1486 }
1487 
1488 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1489 
1490 /*
1491  *      Add data to an sk_buff
1492  */
1493 unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
1494 unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1495 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1496 {
1497         unsigned char *tmp = skb_tail_pointer(skb);
1498         SKB_LINEAR_ASSERT(skb);
1499         skb->tail += len;
1500         skb->len  += len;
1501         return tmp;
1502 }
1503 
1504 unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1505 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1506 {
1507         skb->data -= len;
1508         skb->len  += len;
1509         return skb->data;
1510 }
1511 
1512 unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1513 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1514 {
1515         skb->len -= len;
1516         BUG_ON(skb->len < skb->data_len);
1517         return skb->data += len;
1518 }
1519 
1520 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1521 {
1522         return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1523 }
1524 
1525 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1526 
1527 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1528 {
1529         if (len > skb_headlen(skb) &&
1530             !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1531                 return NULL;
1532         skb->len -= len;
1533         return skb->data += len;
1534 }
1535 
1536 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1537 {
1538         return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1539 }
1540 
1541 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1542 {
1543         if (likely(len <= skb_headlen(skb)))
1544                 return 1;
1545         if (unlikely(len > skb->len))
1546                 return 0;
1547         return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1548 }
1549 
1550 /**
1551  *      skb_headroom - bytes at buffer head
1552  *      @skb: buffer to check
1553  *
1554  *      Return the number of bytes of free space at the head of an &sk_buff.
1555  */
1556 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1557 {
1558         return skb->data - skb->head;
1559 }
1560 
1561 /**
1562  *      skb_tailroom - bytes at buffer end
1563  *      @skb: buffer to check
1564  *
1565  *      Return the number of bytes of free space at the tail of an sk_buff
1566  */
1567 static inline int skb_tailroom(const struct sk_buff *skb)
1568 {
1569         return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1570 }
1571 
1572 /**
1573  *      skb_availroom - bytes at buffer end
1574  *      @skb: buffer to check
1575  *
1576  *      Return the number of bytes of free space at the tail of an sk_buff
1577  *      allocated by sk_stream_alloc()
1578  */
1579 static inline int skb_availroom(const struct sk_buff *skb)
1580 {
1581         if (skb_is_nonlinear(skb))
1582                 return 0;
1583 
1584         return skb->end - skb->tail - skb->reserved_tailroom;
1585 }
1586 
1587 /**
1588  *      skb_reserve - adjust headroom
1589  *      @skb: buffer to alter
1590  *      @len: bytes to move
1591  *
1592  *      Increase the headroom of an empty &sk_buff by reducing the tail
1593  *      room. This is only allowed for an empty buffer.
1594  */
1595 static inline void skb_reserve(struct sk_buff *skb, int len)
1596 {
1597         skb->data += len;
1598         skb->tail += len;
1599 }
1600 
1601 static inline void skb_reset_inner_headers(struct sk_buff *skb)
1602 {
1603         skb->inner_mac_header = skb->mac_header;
1604         skb->inner_network_header = skb->network_header;
1605         skb->inner_transport_header = skb->transport_header;
1606 }
1607 
1608 static inline void skb_reset_mac_len(struct sk_buff *skb)
1609 {
1610         skb->mac_len = skb->network_header - skb->mac_header;
1611 }
1612 
1613 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
1614                                                         *skb)
1615 {
1616         return skb->head + skb->inner_transport_header;
1617 }
1618 
1619 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
1620 {
1621         skb->inner_transport_header = skb->data - skb->head;
1622 }
1623 
1624 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
1625                                                    const int offset)
1626 {
1627         skb_reset_inner_transport_header(skb);
1628         skb->inner_transport_header += offset;
1629 }
1630 
1631 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
1632 {
1633         return skb->head + skb->inner_network_header;
1634 }
1635 
1636 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
1637 {
1638         skb->inner_network_header = skb->data - skb->head;
1639 }
1640 
1641 static inline void skb_set_inner_network_header(struct sk_buff *skb,
1642                                                 const int offset)
1643 {
1644         skb_reset_inner_network_header(skb);
1645         skb->inner_network_header += offset;
1646 }
1647 
1648 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
1649 {
1650         return skb->head + skb->inner_mac_header;
1651 }
1652 
1653 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
1654 {
1655         skb->inner_mac_header = skb->data - skb->head;
1656 }
1657 
1658 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
1659                                             const int offset)
1660 {
1661         skb_reset_inner_mac_header(skb);
1662         skb->inner_mac_header += offset;
1663 }
1664 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
1665 {
1666         return skb->transport_header != (typeof(skb->transport_header))~0U;
1667 }
1668 
1669 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1670 {
1671         return skb->head + skb->transport_header;
1672 }
1673 
1674 static inline void skb_reset_transport_header(struct sk_buff *skb)
1675 {
1676         skb->transport_header = skb->data - skb->head;
1677 }
1678 
1679 static inline void skb_set_transport_header(struct sk_buff *skb,
1680                                             const int offset)
1681 {
1682         skb_reset_transport_header(skb);
1683         skb->transport_header += offset;
1684 }
1685 
1686 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1687 {
1688         return skb->head + skb->network_header;
1689 }
1690 
1691 static inline void skb_reset_network_header(struct sk_buff *skb)
1692 {
1693         skb->network_header = skb->data - skb->head;
1694 }
1695 
1696 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1697 {
1698         skb_reset_network_header(skb);
1699         skb->network_header += offset;
1700 }
1701 
1702 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1703 {
1704         return skb->head + skb->mac_header;
1705 }
1706 
1707 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1708 {
1709         return skb->mac_header != (typeof(skb->mac_header))~0U;
1710 }
1711 
1712 static inline void skb_reset_mac_header(struct sk_buff *skb)
1713 {
1714         skb->mac_header = skb->data - skb->head;
1715 }
1716 
1717 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1718 {
1719         skb_reset_mac_header(skb);
1720         skb->mac_header += offset;
1721 }
1722 
1723 static inline void skb_pop_mac_header(struct sk_buff *skb)
1724 {
1725         skb->mac_header = skb->network_header;
1726 }
1727 
1728 static inline void skb_probe_transport_header(struct sk_buff *skb,
1729                                               const int offset_hint)
1730 {
1731         struct flow_keys keys;
1732 
1733         if (skb_transport_header_was_set(skb))
1734                 return;
1735         else if (skb_flow_dissect(skb, &keys))
1736                 skb_set_transport_header(skb, keys.thoff);
1737         else
1738                 skb_set_transport_header(skb, offset_hint);
1739 }
1740 
1741 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
1742 {
1743         if (skb_mac_header_was_set(skb)) {
1744                 const unsigned char *old_mac = skb_mac_header(skb);
1745 
1746                 skb_set_mac_header(skb, -skb->mac_len);
1747                 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
1748         }
1749 }
1750 
1751 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1752 {
1753         return skb->csum_start - skb_headroom(skb);
1754 }
1755 
1756 static inline int skb_transport_offset(const struct sk_buff *skb)
1757 {
1758         return skb_transport_header(skb) - skb->data;
1759 }
1760 
1761 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1762 {
1763         return skb->transport_header - skb->network_header;
1764 }
1765 
1766 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
1767 {
1768         return skb->inner_transport_header - skb->inner_network_header;
1769 }
1770 
1771 static inline int skb_network_offset(const struct sk_buff *skb)
1772 {
1773         return skb_network_header(skb) - skb->data;
1774 }
1775 
1776 static inline int skb_inner_network_offset(const struct sk_buff *skb)
1777 {
1778         return skb_inner_network_header(skb) - skb->data;
1779 }
1780 
1781 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1782 {
1783         return pskb_may_pull(skb, skb_network_offset(skb) + len);
1784 }
1785 
1786 /*
1787  * CPUs often take a performance hit when accessing unaligned memory
1788  * locations. The actual performance hit varies, it can be small if the
1789  * hardware handles it or large if we have to take an exception and fix it
1790  * in software.
1791  *
1792  * Since an ethernet header is 14 bytes network drivers often end up with
1793  * the IP header at an unaligned offset. The IP header can be aligned by
1794  * shifting the start of the packet by 2 bytes. Drivers should do this
1795  * with:
1796  *
1797  * skb_reserve(skb, NET_IP_ALIGN);
1798  *
1799  * The downside to this alignment of the IP header is that the DMA is now
1800  * unaligned. On some architectures the cost of an unaligned DMA is high
1801  * and this cost outweighs the gains made by aligning the IP header.
1802  *
1803  * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1804  * to be overridden.
1805  */
1806 #ifndef NET_IP_ALIGN
1807 #define NET_IP_ALIGN    2
1808 #endif
1809 
1810 /*
1811  * The networking layer reserves some headroom in skb data (via
1812  * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1813  * the header has to grow. In the default case, if the header has to grow
1814  * 32 bytes or less we avoid the reallocation.
1815  *
1816  * Unfortunately this headroom changes the DMA alignment of the resulting
1817  * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1818  * on some architectures. An architecture can override this value,
1819  * perhaps setting it to a cacheline in size (since that will maintain
1820  * cacheline alignment of the DMA). It must be a power of 2.
1821  *
1822  * Various parts of the networking layer expect at least 32 bytes of
1823  * headroom, you should not reduce this.
1824  *
1825  * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1826  * to reduce average number of cache lines per packet.
1827  * get_rps_cpus() for example only access one 64 bytes aligned block :
1828  * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1829  */
1830 #ifndef NET_SKB_PAD
1831 #define NET_SKB_PAD     max(32, L1_CACHE_BYTES)
1832 #endif
1833 
1834 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1835 
1836 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1837 {
1838         if (unlikely(skb_is_nonlinear(skb))) {
1839                 WARN_ON(1);
1840                 return;
1841         }
1842         skb->len = len;
1843         skb_set_tail_pointer(skb, len);
1844 }
1845 
1846 void skb_trim(struct sk_buff *skb, unsigned int len);
1847 
1848 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1849 {
1850         if (skb->data_len)
1851                 return ___pskb_trim(skb, len);
1852         __skb_trim(skb, len);
1853         return 0;
1854 }
1855 
1856 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1857 {
1858         return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1859 }
1860 
1861 /**
1862  *      pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1863  *      @skb: buffer to alter
1864  *      @len: new length
1865  *
1866  *      This is identical to pskb_trim except that the caller knows that
1867  *      the skb is not cloned so we should never get an error due to out-
1868  *      of-memory.
1869  */
1870 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1871 {
1872         int err = pskb_trim(skb, len);
1873         BUG_ON(err);
1874 }
1875 
1876 /**
1877  *      skb_orphan - orphan a buffer
1878  *      @skb: buffer to orphan
1879  *
1880  *      If a buffer currently has an owner then we call the owner's
1881  *      destructor function and make the @skb unowned. The buffer continues
1882  *      to exist but is no longer charged to its former owner.
1883  */
1884 static inline void skb_orphan(struct sk_buff *skb)
1885 {
1886         if (skb->destructor) {
1887                 skb->destructor(skb);
1888                 skb->destructor = NULL;
1889                 skb->sk         = NULL;
1890         } else {
1891                 BUG_ON(skb->sk);
1892         }
1893 }
1894 
1895 /**
1896  *      skb_orphan_frags - orphan the frags contained in a buffer
1897  *      @skb: buffer to orphan frags from
1898  *      @gfp_mask: allocation mask for replacement pages
1899  *
1900  *      For each frag in the SKB which needs a destructor (i.e. has an
1901  *      owner) create a copy of that frag and release the original
1902  *      page by calling the destructor.
1903  */
1904 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
1905 {
1906         if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
1907                 return 0;
1908         return skb_copy_ubufs(skb, gfp_mask);
1909 }
1910 
1911 /**
1912  *      __skb_queue_purge - empty a list
1913  *      @list: list to empty
1914  *
1915  *      Delete all buffers on an &sk_buff list. Each buffer is removed from
1916  *      the list and one reference dropped. This function does not take the
1917  *      list lock and the caller must hold the relevant locks to use it.
1918  */
1919 void skb_queue_purge(struct sk_buff_head *list);
1920 static inline void __skb_queue_purge(struct sk_buff_head *list)
1921 {
1922         struct sk_buff *skb;
1923         while ((skb = __skb_dequeue(list)) != NULL)
1924                 kfree_skb(skb);
1925 }
1926 
1927 #define NETDEV_FRAG_PAGE_MAX_ORDER get_order(32768)
1928 #define NETDEV_FRAG_PAGE_MAX_SIZE  (PAGE_SIZE << NETDEV_FRAG_PAGE_MAX_ORDER)
1929 #define NETDEV_PAGECNT_MAX_BIAS    NETDEV_FRAG_PAGE_MAX_SIZE
1930 
1931 void *netdev_alloc_frag(unsigned int fragsz);
1932 
1933 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
1934                                    gfp_t gfp_mask);
1935 
1936 /**
1937  *      netdev_alloc_skb - allocate an skbuff for rx on a specific device
1938  *      @dev: network device to receive on
1939  *      @length: length to allocate
1940  *
1941  *      Allocate a new &sk_buff and assign it a usage count of one. The
1942  *      buffer has unspecified headroom built in. Users should allocate
1943  *      the headroom they think they need without accounting for the
1944  *      built in space. The built in space is used for optimisations.
1945  *
1946  *      %NULL is returned if there is no free memory. Although this function
1947  *      allocates memory it can be called from an interrupt.
1948  */
1949 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1950                                                unsigned int length)
1951 {
1952         return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1953 }
1954 
1955 /* legacy helper around __netdev_alloc_skb() */
1956 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1957                                               gfp_t gfp_mask)
1958 {
1959         return __netdev_alloc_skb(NULL, length, gfp_mask);
1960 }
1961 
1962 /* legacy helper around netdev_alloc_skb() */
1963 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1964 {
1965         return netdev_alloc_skb(NULL, length);
1966 }
1967 
1968 
1969 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1970                 unsigned int length, gfp_t gfp)
1971 {
1972         struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1973 
1974         if (NET_IP_ALIGN && skb)
1975                 skb_reserve(skb, NET_IP_ALIGN);
1976         return skb;
1977 }
1978 
1979 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1980                 unsigned int length)
1981 {
1982         return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1983 }
1984 
1985 /**
1986  *      __skb_alloc_pages - allocate pages for ps-rx on a skb and preserve pfmemalloc data
1987  *      @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1988  *      @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1989  *      @order: size of the allocation
1990  *
1991  *      Allocate a new page.
1992  *
1993  *      %NULL is returned if there is no free memory.
1994 */
1995 static inline struct page *__skb_alloc_pages(gfp_t gfp_mask,
1996                                               struct sk_buff *skb,
1997                                               unsigned int order)
1998 {
1999         struct page *page;
2000 
2001         gfp_mask |= __GFP_COLD;
2002 
2003         if (!(gfp_mask & __GFP_NOMEMALLOC))
2004                 gfp_mask |= __GFP_MEMALLOC;
2005 
2006         page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2007         if (skb && page && page->pfmemalloc)
2008                 skb->pfmemalloc = true;
2009 
2010         return page;
2011 }
2012 
2013 /**
2014  *      __skb_alloc_page - allocate a page for ps-rx for a given skb and preserve pfmemalloc data
2015  *      @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
2016  *      @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
2017  *
2018  *      Allocate a new page.
2019  *
2020  *      %NULL is returned if there is no free memory.
2021  */
2022 static inline struct page *__skb_alloc_page(gfp_t gfp_mask,
2023                                              struct sk_buff *skb)
2024 {
2025         return __skb_alloc_pages(gfp_mask, skb, 0);
2026 }
2027 
2028 /**
2029  *      skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2030  *      @page: The page that was allocated from skb_alloc_page
2031  *      @skb: The skb that may need pfmemalloc set
2032  */
2033 static inline void skb_propagate_pfmemalloc(struct page *page,
2034                                              struct sk_buff *skb)
2035 {
2036         if (page && page->pfmemalloc)
2037                 skb->pfmemalloc = true;
2038 }
2039 
2040 /**
2041  * skb_frag_page - retrieve the page refered to by a paged fragment
2042  * @frag: the paged fragment
2043  *
2044  * Returns the &struct page associated with @frag.
2045  */
2046 static inline struct page *skb_frag_page(const skb_frag_t *frag)
2047 {
2048         return frag->page.p;
2049 }
2050 
2051 /**
2052  * __skb_frag_ref - take an addition reference on a paged fragment.
2053  * @frag: the paged fragment
2054  *
2055  * Takes an additional reference on the paged fragment @frag.
2056  */
2057 static inline void __skb_frag_ref(skb_frag_t *frag)
2058 {
2059         get_page(skb_frag_page(frag));
2060 }
2061 
2062 /**
2063  * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2064  * @skb: the buffer
2065  * @f: the fragment offset.
2066  *
2067  * Takes an additional reference on the @f'th paged fragment of @skb.
2068  */
2069 static inline void skb_frag_ref(struct sk_buff *skb, int f)
2070 {
2071         __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2072 }
2073 
2074 /**
2075  * __skb_frag_unref - release a reference on a paged fragment.
2076  * @frag: the paged fragment
2077  *
2078  * Releases a reference on the paged fragment @frag.
2079  */
2080 static inline void __skb_frag_unref(skb_frag_t *frag)
2081 {
2082         put_page(skb_frag_page(frag));
2083 }
2084 
2085 /**
2086  * skb_frag_unref - release a reference on a paged fragment of an skb.
2087  * @skb: the buffer
2088  * @f: the fragment offset
2089  *
2090  * Releases a reference on the @f'th paged fragment of @skb.
2091  */
2092 static inline void skb_frag_unref(struct sk_buff *skb, int f)
2093 {
2094         __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2095 }
2096 
2097 /**
2098  * skb_frag_address - gets the address of the data contained in a paged fragment
2099  * @frag: the paged fragment buffer
2100  *
2101  * Returns the address of the data within @frag. The page must already
2102  * be mapped.
2103  */
2104 static inline void *skb_frag_address(const skb_frag_t *frag)
2105 {
2106         return page_address(skb_frag_page(frag)) + frag->page_offset;
2107 }
2108 
2109 /**
2110  * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2111  * @frag: the paged fragment buffer
2112  *
2113  * Returns the address of the data within @frag. Checks that the page
2114  * is mapped and returns %NULL otherwise.
2115  */
2116 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2117 {
2118         void *ptr = page_address(skb_frag_page(frag));
2119         if (unlikely(!ptr))
2120                 return NULL;
2121 
2122         return ptr + frag->page_offset;
2123 }
2124 
2125 /**
2126  * __skb_frag_set_page - sets the page contained in a paged fragment
2127  * @frag: the paged fragment
2128  * @page: the page to set
2129  *
2130  * Sets the fragment @frag to contain @page.
2131  */
2132 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2133 {
2134         frag->page.p = page;
2135 }
2136 
2137 /**
2138  * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2139  * @skb: the buffer
2140  * @f: the fragment offset
2141  * @page: the page to set
2142  *
2143  * Sets the @f'th fragment of @skb to contain @page.
2144  */
2145 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2146                                      struct page *page)
2147 {
2148         __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2149 }
2150 
2151 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2152 
2153 /**
2154  * skb_frag_dma_map - maps a paged fragment via the DMA API
2155  * @dev: the device to map the fragment to
2156  * @frag: the paged fragment to map
2157  * @offset: the offset within the fragment (starting at the
2158  *          fragment's own offset)
2159  * @size: the number of bytes to map
2160  * @dir: the direction of the mapping (%PCI_DMA_*)
2161  *
2162  * Maps the page associated with @frag to @device.
2163  */
2164 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2165                                           const skb_frag_t *frag,
2166                                           size_t offset, size_t size,
2167                                           enum dma_data_direction dir)
2168 {
2169         return dma_map_page(dev, skb_frag_page(frag),
2170                             frag->page_offset + offset, size, dir);
2171 }
2172 
2173 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2174                                         gfp_t gfp_mask)
2175 {
2176         return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2177 }
2178 
2179 /**
2180  *      skb_clone_writable - is the header of a clone writable
2181  *      @skb: buffer to check
2182  *      @len: length up to which to write
2183  *
2184  *      Returns true if modifying the header part of the cloned buffer
2185  *      does not requires the data to be copied.
2186  */
2187 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2188 {
2189         return !skb_header_cloned(skb) &&
2190                skb_headroom(skb) + len <= skb->hdr_len;
2191 }
2192 
2193 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2194                             int cloned)
2195 {
2196         int delta = 0;
2197 
2198         if (headroom > skb_headroom(skb))
2199                 delta = headroom - skb_headroom(skb);
2200 
2201         if (delta || cloned)
2202                 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2203                                         GFP_ATOMIC);
2204         return 0;
2205 }
2206 
2207 /**
2208  *      skb_cow - copy header of skb when it is required
2209  *      @skb: buffer to cow
2210  *      @headroom: needed headroom
2211  *
2212  *      If the skb passed lacks sufficient headroom or its data part
2213  *      is shared, data is reallocated. If reallocation fails, an error
2214  *      is returned and original skb is not changed.
2215  *
2216  *      The result is skb with writable area skb->head...skb->tail
2217  *      and at least @headroom of space at head.
2218  */
2219 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2220 {
2221         return __skb_cow(skb, headroom, skb_cloned(skb));
2222 }
2223 
2224 /**
2225  *      skb_cow_head - skb_cow but only making the head writable
2226  *      @skb: buffer to cow
2227  *      @headroom: needed headroom
2228  *
2229  *      This function is identical to skb_cow except that we replace the
2230  *      skb_cloned check by skb_header_cloned.  It should be used when
2231  *      you only need to push on some header and do not need to modify
2232  *      the data.
2233  */
2234 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2235 {
2236         return __skb_cow(skb, headroom, skb_header_cloned(skb));
2237 }
2238 
2239 /**
2240  *      skb_padto       - pad an skbuff up to a minimal size
2241  *      @skb: buffer to pad
2242  *      @len: minimal length
2243  *
2244  *      Pads up a buffer to ensure the trailing bytes exist and are
2245  *      blanked. If the buffer already contains sufficient data it
2246  *      is untouched. Otherwise it is extended. Returns zero on
2247  *      success. The skb is freed on error.
2248  */
2249  
2250 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2251 {
2252         unsigned int size = skb->len;
2253         if (likely(size >= len))
2254                 return 0;
2255         return skb_pad(skb, len - size);
2256 }
2257 
2258 static inline int skb_add_data(struct sk_buff *skb,
2259                                char __user *from, int copy)
2260 {
2261         const int off = skb->len;
2262 
2263         if (skb->ip_summed == CHECKSUM_NONE) {
2264                 int err = 0;
2265                 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
2266                                                             copy, 0, &err);
2267                 if (!err) {
2268                         skb->csum = csum_block_add(skb->csum, csum, off);
2269                         return 0;
2270                 }
2271         } else if (!copy_from_user(skb_put(skb, copy), from, copy))
2272                 return 0;
2273 
2274         __skb_trim(skb, off);
2275         return -EFAULT;
2276 }
2277 
2278 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2279                                     const struct page *page, int off)
2280 {
2281         if (i) {
2282                 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2283 
2284                 return page == skb_frag_page(frag) &&
2285                        off == frag->page_offset + skb_frag_size(frag);
2286         }
2287         return false;
2288 }
2289 
2290 static inline int __skb_linearize(struct sk_buff *skb)
2291 {
2292         return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2293 }
2294 
2295 /**
2296  *      skb_linearize - convert paged skb to linear one
2297  *      @skb: buffer to linarize
2298  *
2299  *      If there is no free memory -ENOMEM is returned, otherwise zero
2300  *      is returned and the old skb data released.
2301  */
2302 static inline int skb_linearize(struct sk_buff *skb)
2303 {
2304         return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2305 }
2306 
2307 /**
2308  * skb_has_shared_frag - can any frag be overwritten
2309  * @skb: buffer to test
2310  *
2311  * Return true if the skb has at least one frag that might be modified
2312  * by an external entity (as in vmsplice()/sendfile())
2313  */
2314 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2315 {
2316         return skb_is_nonlinear(skb) &&
2317                skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2318 }
2319 
2320 /**
2321  *      skb_linearize_cow - make sure skb is linear and writable
2322  *      @skb: buffer to process
2323  *
2324  *      If there is no free memory -ENOMEM is returned, otherwise zero
2325  *      is returned and the old skb data released.
2326  */
2327 static inline int skb_linearize_cow(struct sk_buff *skb)
2328 {
2329         return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2330                __skb_linearize(skb) : 0;
2331 }
2332 
2333 /**
2334  *      skb_postpull_rcsum - update checksum for received skb after pull
2335  *      @skb: buffer to update
2336  *      @start: start of data before pull
2337  *      @len: length of data pulled
2338  *
2339  *      After doing a pull on a received packet, you need to call this to
2340  *      update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2341  *      CHECKSUM_NONE so that it can be recomputed from scratch.
2342  */
2343 
2344 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2345                                       const void *start, unsigned int len)
2346 {
2347         if (skb->ip_summed == CHECKSUM_COMPLETE)
2348                 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
2349 }
2350 
2351 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2352 
2353 /**
2354  *      pskb_trim_rcsum - trim received skb and update checksum
2355  *      @skb: buffer to trim
2356  *      @len: new length
2357  *
2358  *      This is exactly the same as pskb_trim except that it ensures the
2359  *      checksum of received packets are still valid after the operation.
2360  */
2361 
2362 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2363 {
2364         if (likely(len >= skb->len))
2365                 return 0;
2366         if (skb->ip_summed == CHECKSUM_COMPLETE)
2367                 skb->ip_summed = CHECKSUM_NONE;
2368         return __pskb_trim(skb, len);
2369 }
2370 
2371 #define skb_queue_walk(queue, skb) \
2372                 for (skb = (queue)->next;                                       \
2373                      skb != (struct sk_buff *)(queue);                          \
2374                      skb = skb->next)
2375 
2376 #define skb_queue_walk_safe(queue, skb, tmp)                                    \
2377                 for (skb = (queue)->next, tmp = skb->next;                      \
2378                      skb != (struct sk_buff *)(queue);                          \
2379                      skb = tmp, tmp = skb->next)
2380 
2381 #define skb_queue_walk_from(queue, skb)                                         \
2382                 for (; skb != (struct sk_buff *)(queue);                        \
2383                      skb = skb->next)
2384 
2385 #define skb_queue_walk_from_safe(queue, skb, tmp)                               \
2386                 for (tmp = skb->next;                                           \
2387                      skb != (struct sk_buff *)(queue);                          \
2388                      skb = tmp, tmp = skb->next)
2389 
2390 #define skb_queue_reverse_walk(queue, skb) \
2391                 for (skb = (queue)->prev;                                       \
2392                      skb != (struct sk_buff *)(queue);                          \
2393                      skb = skb->prev)
2394 
2395 #define skb_queue_reverse_walk_safe(queue, skb, tmp)                            \
2396                 for (skb = (queue)->prev, tmp = skb->prev;                      \
2397                      skb != (struct sk_buff *)(queue);                          \
2398                      skb = tmp, tmp = skb->prev)
2399 
2400 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp)                       \
2401                 for (tmp = skb->prev;                                           \
2402                      skb != (struct sk_buff *)(queue);                          \
2403                      skb = tmp, tmp = skb->prev)
2404 
2405 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2406 {
2407         return skb_shinfo(skb)->frag_list != NULL;
2408 }
2409 
2410 static inline void skb_frag_list_init(struct sk_buff *skb)
2411 {
2412         skb_shinfo(skb)->frag_list = NULL;
2413 }
2414 
2415 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2416 {
2417         frag->next = skb_shinfo(skb)->frag_list;
2418         skb_shinfo(skb)->frag_list = frag;
2419 }
2420 
2421 #define skb_walk_frags(skb, iter)       \
2422         for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2423 
2424 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2425                                     int *peeked, int *off, int *err);
2426 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
2427                                   int *err);
2428 unsigned int datagram_poll(struct file *file, struct socket *sock,
2429                            struct poll_table_struct *wait);
2430 int skb_copy_datagram_iovec(const struct sk_buff *from, int offset,
2431                             struct iovec *to, int size);
2432 int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen,
2433                                      struct iovec *iov);
2434 int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,
2435                                  const struct iovec *from, int from_offset,
2436                                  int len);
2437 int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *frm,
2438                            int offset, size_t count);
2439 int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset,
2440                                   const struct iovec *to, int to_offset,
2441                                   int size);
2442 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2443 void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);
2444 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
2445 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
2446 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
2447 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
2448                               int len, __wsum csum);
2449 int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
2450                     struct pipe_inode_info *pipe, unsigned int len,
2451                     unsigned int flags);
2452 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2453 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
2454 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
2455                  int len, int hlen);
2456 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
2457 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
2458 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
2459 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
2460 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
2461 
2462 struct skb_checksum_ops {
2463         __wsum (*update)(const void *mem, int len, __wsum wsum);
2464         __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
2465 };
2466 
2467 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2468                       __wsum csum, const struct skb_checksum_ops *ops);
2469 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
2470                     __wsum csum);
2471 
2472 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2473                                        int len, void *buffer)
2474 {
2475         int hlen = skb_headlen(skb);
2476 
2477         if (hlen - offset >= len)
2478                 return skb->data + offset;
2479 
2480         if (skb_copy_bits(skb, offset, buffer, len) < 0)
2481                 return NULL;
2482 
2483         return buffer;
2484 }
2485 
2486 /**
2487  *      skb_needs_linearize - check if we need to linearize a given skb
2488  *                            depending on the given device features.
2489  *      @skb: socket buffer to check
2490  *      @features: net device features
2491  *
2492  *      Returns true if either:
2493  *      1. skb has frag_list and the device doesn't support FRAGLIST, or
2494  *      2. skb is fragmented and the device does not support SG.
2495  */
2496 static inline bool skb_needs_linearize(struct sk_buff *skb,
2497                                        netdev_features_t features)
2498 {
2499         return skb_is_nonlinear(skb) &&
2500                ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
2501                 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
2502 }
2503 
2504 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2505                                              void *to,
2506                                              const unsigned int len)
2507 {
2508         memcpy(to, skb->data, len);
2509 }
2510 
2511 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2512                                                     const int offset, void *to,
2513                                                     const unsigned int len)
2514 {
2515         memcpy(to, skb->data + offset, len);
2516 }
2517 
2518 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2519                                            const void *from,
2520                                            const unsigned int len)
2521 {
2522         memcpy(skb->data, from, len);
2523 }
2524 
2525 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2526                                                   const int offset,
2527                                                   const void *from,
2528                                                   const unsigned int len)
2529 {
2530         memcpy(skb->data + offset, from, len);
2531 }
2532 
2533 void skb_init(void);
2534 
2535 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2536 {
2537         return skb->tstamp;
2538 }
2539 
2540 /**
2541  *      skb_get_timestamp - get timestamp from a skb
2542  *      @skb: skb to get stamp from
2543  *      @stamp: pointer to struct timeval to store stamp in
2544  *
2545  *      Timestamps are stored in the skb as offsets to a base timestamp.
2546  *      This function converts the offset back to a struct timeval and stores
2547  *      it in stamp.
2548  */
2549 static inline void skb_get_timestamp(const struct sk_buff *skb,
2550                                      struct timeval *stamp)
2551 {
2552         *stamp = ktime_to_timeval(skb->tstamp);
2553 }
2554 
2555 static inline void skb_get_timestampns(const struct sk_buff *skb,
2556                                        struct timespec *stamp)
2557 {
2558         *stamp = ktime_to_timespec(skb->tstamp);
2559 }
2560 
2561 static inline void __net_timestamp(struct sk_buff *skb)
2562 {
2563         skb->tstamp = ktime_get_real();
2564 }
2565 
2566 static inline ktime_t net_timedelta(ktime_t t)
2567 {
2568         return ktime_sub(ktime_get_real(), t);
2569 }
2570 
2571 static inline ktime_t net_invalid_timestamp(void)
2572 {
2573         return ktime_set(0, 0);
2574 }
2575 
2576 void skb_timestamping_init(void);
2577 
2578 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2579 
2580 void skb_clone_tx_timestamp(struct sk_buff *skb);
2581 bool skb_defer_rx_timestamp(struct sk_buff *skb);
2582 
2583 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2584 
2585 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2586 {
2587 }
2588 
2589 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2590 {
2591         return false;
2592 }
2593 
2594 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2595 
2596 /**
2597  * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2598  *
2599  * PHY drivers may accept clones of transmitted packets for
2600  * timestamping via their phy_driver.txtstamp method. These drivers
2601  * must call this function to return the skb back to the stack, with
2602  * or without a timestamp.
2603  *
2604  * @skb: clone of the the original outgoing packet
2605  * @hwtstamps: hardware time stamps, may be NULL if not available
2606  *
2607  */
2608 void skb_complete_tx_timestamp(struct sk_buff *skb,
2609                                struct skb_shared_hwtstamps *hwtstamps);
2610 
2611 /**
2612  * skb_tstamp_tx - queue clone of skb with send time stamps
2613  * @orig_skb:   the original outgoing packet
2614  * @hwtstamps:  hardware time stamps, may be NULL if not available
2615  *
2616  * If the skb has a socket associated, then this function clones the
2617  * skb (thus sharing the actual data and optional structures), stores
2618  * the optional hardware time stamping information (if non NULL) or
2619  * generates a software time stamp (otherwise), then queues the clone
2620  * to the error queue of the socket.  Errors are silently ignored.
2621  */
2622 void skb_tstamp_tx(struct sk_buff *orig_skb,
2623                    struct skb_shared_hwtstamps *hwtstamps);
2624 
2625 static inline void sw_tx_timestamp(struct sk_buff *skb)
2626 {
2627         if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2628             !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2629                 skb_tstamp_tx(skb, NULL);
2630 }
2631 
2632 /**
2633  * skb_tx_timestamp() - Driver hook for transmit timestamping
2634  *
2635  * Ethernet MAC Drivers should call this function in their hard_xmit()
2636  * function immediately before giving the sk_buff to the MAC hardware.
2637  *
2638  * Specifically, one should make absolutely sure that this function is
2639  * called before TX completion of this packet can trigger.  Otherwise
2640  * the packet could potentially already be freed.
2641  *
2642  * @skb: A socket buffer.
2643  */
2644 static inline void skb_tx_timestamp(struct sk_buff *skb)
2645 {
2646         skb_clone_tx_timestamp(skb);
2647         sw_tx_timestamp(skb);
2648 }
2649 
2650 /**
2651  * skb_complete_wifi_ack - deliver skb with wifi status
2652  *
2653  * @skb: the original outgoing packet
2654  * @acked: ack status
2655  *
2656  */
2657 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
2658 
2659 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2660 __sum16 __skb_checksum_complete(struct sk_buff *skb);
2661 
2662 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2663 {
2664         return skb->ip_summed & CHECKSUM_UNNECESSARY;
2665 }
2666 
2667 /**
2668  *      skb_checksum_complete - Calculate checksum of an entire packet
2669  *      @skb: packet to process
2670  *
2671  *      This function calculates the checksum over the entire packet plus
2672  *      the value of skb->csum.  The latter can be used to supply the
2673  *      checksum of a pseudo header as used by TCP/UDP.  It returns the
2674  *      checksum.
2675  *
2676  *      For protocols that contain complete checksums such as ICMP/TCP/UDP,
2677  *      this function can be used to verify that checksum on received
2678  *      packets.  In that case the function should return zero if the
2679  *      checksum is correct.  In particular, this function will return zero
2680  *      if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2681  *      hardware has already verified the correctness of the checksum.
2682  */
2683 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2684 {
2685         return skb_csum_unnecessary(skb) ?
2686                0 : __skb_checksum_complete(skb);
2687 }
2688 
2689 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2690 void nf_conntrack_destroy(struct nf_conntrack *nfct);
2691 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2692 {
2693         if (nfct && atomic_dec_and_test(&nfct->use))
2694                 nf_conntrack_destroy(nfct);
2695 }
2696 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2697 {
2698         if (nfct)
2699                 atomic_inc(&nfct->use);
2700 }
2701 #endif
2702 #ifdef CONFIG_BRIDGE_NETFILTER
2703 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2704 {
2705         if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2706                 kfree(nf_bridge);
2707 }
2708 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2709 {
2710         if (nf_bridge)
2711                 atomic_inc(&nf_bridge->use);
2712 }
2713 #endif /* CONFIG_BRIDGE_NETFILTER */
2714 static inline void nf_reset(struct sk_buff *skb)
2715 {
2716 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2717         nf_conntrack_put(skb->nfct);
2718         skb->nfct = NULL;
2719 #endif
2720 #ifdef CONFIG_BRIDGE_NETFILTER
2721         nf_bridge_put(skb->nf_bridge);
2722         skb->nf_bridge = NULL;
2723 #endif
2724 }
2725 
2726 static inline void nf_reset_trace(struct sk_buff *skb)
2727 {
2728 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
2729         skb->nf_trace = 0;
2730 #endif
2731 }
2732 
2733 /* Note: This doesn't put any conntrack and bridge info in dst. */
2734 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2735 {
2736 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2737         dst->nfct = src->nfct;
2738         nf_conntrack_get(src->nfct);
2739         dst->nfctinfo = src->nfctinfo;
2740 #endif
2741 #ifdef CONFIG_BRIDGE_NETFILTER
2742         dst->nf_bridge  = src->nf_bridge;
2743         nf_bridge_get(src->nf_bridge);
2744 #endif
2745 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
2746         dst->nf_trace = src->nf_trace;
2747 #endif
2748 }
2749 
2750 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2751 {
2752 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2753         nf_conntrack_put(dst->nfct);
2754 #endif
2755 #ifdef CONFIG_BRIDGE_NETFILTER
2756         nf_bridge_put(dst->nf_bridge);
2757 #endif
2758         __nf_copy(dst, src);
2759 }
2760 
2761 #ifdef CONFIG_NETWORK_SECMARK
2762 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2763 {
2764         to->secmark = from->secmark;
2765 }
2766 
2767 static inline void skb_init_secmark(struct sk_buff *skb)
2768 {
2769         skb->secmark = 0;
2770 }
2771 #else
2772 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2773 { }
2774 
2775 static inline void skb_init_secmark(struct sk_buff *skb)
2776 { }
2777 #endif
2778 
2779 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2780 {
2781         skb->queue_mapping = queue_mapping;
2782 }
2783 
2784 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2785 {
2786         return skb->queue_mapping;
2787 }
2788 
2789 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2790 {
2791         to->queue_mapping = from->queue_mapping;
2792 }
2793 
2794 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2795 {
2796         skb->queue_mapping = rx_queue + 1;
2797 }
2798 
2799 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2800 {
2801         return skb->queue_mapping - 1;
2802 }
2803 
2804 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2805 {
2806         return skb->queue_mapping != 0;
2807 }
2808 
2809 u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
2810                   unsigned int num_tx_queues);
2811 
2812 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2813 {
2814 #ifdef CONFIG_XFRM
2815         return skb->sp;
2816 #else
2817         return NULL;
2818 #endif
2819 }
2820 
2821 /* Keeps track of mac header offset relative to skb->head.
2822  * It is useful for TSO of Tunneling protocol. e.g. GRE.
2823  * For non-tunnel skb it points to skb_mac_header() and for
2824  * tunnel skb it points to outer mac header.
2825  * Keeps track of level of encapsulation of network headers.
2826  */
2827 struct skb_gso_cb {
2828         int     mac_offset;
2829         int     encap_level;
2830 };
2831 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
2832 
2833 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
2834 {
2835         return (skb_mac_header(inner_skb) - inner_skb->head) -
2836                 SKB_GSO_CB(inner_skb)->mac_offset;
2837 }
2838 
2839 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
2840 {
2841         int new_headroom, headroom;
2842         int ret;
2843 
2844         headroom = skb_headroom(skb);
2845         ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
2846         if (ret)
2847                 return ret;
2848 
2849         new_headroom = skb_headroom(skb);
2850         SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
2851         return 0;
2852 }
2853 
2854 static inline bool skb_is_gso(const struct sk_buff *skb)
2855 {
2856         return skb_shinfo(skb)->gso_size;
2857 }
2858 
2859 /* Note: Should be called only if skb_is_gso(skb) is true */
2860 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
2861 {
2862         return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2863 }
2864 
2865 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2866 
2867 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2868 {
2869         /* LRO sets gso_size but not gso_type, whereas if GSO is really
2870          * wanted then gso_type will be set. */
2871         const struct skb_shared_info *shinfo = skb_shinfo(skb);
2872 
2873         if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2874             unlikely(shinfo->gso_type == 0)) {
2875                 __skb_warn_lro_forwarding(skb);
2876                 return true;
2877         }
2878         return false;
2879 }
2880 
2881 static inline void skb_forward_csum(struct sk_buff *skb)
2882 {
2883         /* Unfortunately we don't support this one.  Any brave souls? */
2884         if (skb->ip_summed == CHECKSUM_COMPLETE)
2885                 skb->ip_summed = CHECKSUM_NONE;
2886 }
2887 
2888 /**
2889  * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2890  * @skb: skb to check
2891  *
2892  * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2893  * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2894  * use this helper, to document places where we make this assertion.
2895  */
2896 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2897 {
2898 #ifdef DEBUG
2899         BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2900 #endif
2901 }
2902 
2903 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2904 
2905 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
2906 
2907 u32 __skb_get_poff(const struct sk_buff *skb);
2908 
2909 /**
2910  * skb_head_is_locked - Determine if the skb->head is locked down
2911  * @skb: skb to check
2912  *
2913  * The head on skbs build around a head frag can be removed if they are
2914  * not cloned.  This function returns true if the skb head is locked down
2915  * due to either being allocated via kmalloc, or by being a clone with
2916  * multiple references to the head.
2917  */
2918 static inline bool skb_head_is_locked(const struct sk_buff *skb)
2919 {
2920         return !skb->head_frag || skb_cloned(skb);
2921 }
2922 
2923 /**
2924  * skb_gso_network_seglen - Return length of individual segments of a gso packet
2925  *
2926  * @skb: GSO skb
2927  *
2928  * skb_gso_network_seglen is used to determine the real size of the
2929  * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
2930  *
2931  * The MAC/L2 header is not accounted for.
2932  */
2933 static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
2934 {
2935         unsigned int hdr_len = skb_transport_header(skb) -
2936                                skb_network_header(skb);
2937         return hdr_len + skb_gso_transport_seglen(skb);
2938 }
2939 #endif  /* __KERNEL__ */
2940 #endif  /* _LINUX_SKBUFF_H */
2941 

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