xref: /linux/include/linux/skbuff.h (revision 07fdad3a93756b872da7b53647715c48d0f4a2d0)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  *	Definitions for the 'struct sk_buff' memory handlers.
4  *
5  *	Authors:
6  *		Alan Cox, <gw4pts@gw4pts.ampr.org>
7  *		Florian La Roche, <rzsfl@rz.uni-sb.de>
8  */
9 
10 #ifndef _LINUX_SKBUFF_H
11 #define _LINUX_SKBUFF_H
12 
13 #include <linux/kernel.h>
14 #include <linux/compiler.h>
15 #include <linux/time.h>
16 #include <linux/bug.h>
17 #include <linux/bvec.h>
18 #include <linux/cache.h>
19 #include <linux/rbtree.h>
20 #include <linux/socket.h>
21 #include <linux/refcount.h>
22 
23 #include <linux/atomic.h>
24 #include <asm/types.h>
25 #include <linux/spinlock.h>
26 #include <net/checksum.h>
27 #include <linux/rcupdate.h>
28 #include <linux/dma-mapping.h>
29 #include <linux/netdev_features.h>
30 #include <net/flow_dissector.h>
31 #include <linux/in6.h>
32 #include <linux/if_packet.h>
33 #include <linux/llist.h>
34 #include <linux/page_frag_cache.h>
35 #include <net/flow.h>
36 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
37 #include <linux/netfilter/nf_conntrack_common.h>
38 #endif
39 #include <net/net_debug.h>
40 #include <net/dropreason-core.h>
41 #include <net/netmem.h>
42 
43 /**
44  * DOC: skb checksums
45  *
46  * The interface for checksum offload between the stack and networking drivers
47  * is as follows...
48  *
49  * IP checksum related features
50  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
51  *
52  * Drivers advertise checksum offload capabilities in the features of a device.
53  * From the stack's point of view these are capabilities offered by the driver.
54  * A driver typically only advertises features that it is capable of offloading
55  * to its device.
56  *
57  * .. flat-table:: Checksum related device features
58  *   :widths: 1 10
59  *
60  *   * - %NETIF_F_HW_CSUM
61  *     - The driver (or its device) is able to compute one
62  *	 IP (one's complement) checksum for any combination
63  *	 of protocols or protocol layering. The checksum is
64  *	 computed and set in a packet per the CHECKSUM_PARTIAL
65  *	 interface (see below).
66  *
67  *   * - %NETIF_F_IP_CSUM
68  *     - Driver (device) is only able to checksum plain
69  *	 TCP or UDP packets over IPv4. These are specifically
70  *	 unencapsulated packets of the form IPv4|TCP or
71  *	 IPv4|UDP where the Protocol field in the IPv4 header
72  *	 is TCP or UDP. The IPv4 header may contain IP options.
73  *	 This feature cannot be set in features for a device
74  *	 with NETIF_F_HW_CSUM also set. This feature is being
75  *	 DEPRECATED (see below).
76  *
77  *   * - %NETIF_F_IPV6_CSUM
78  *     - Driver (device) is only able to checksum plain
79  *	 TCP or UDP packets over IPv6. These are specifically
80  *	 unencapsulated packets of the form IPv6|TCP or
81  *	 IPv6|UDP where the Next Header field in the IPv6
82  *	 header is either TCP or UDP. IPv6 extension headers
83  *	 are not supported with this feature. This feature
84  *	 cannot be set in features for a device with
85  *	 NETIF_F_HW_CSUM also set. This feature is being
86  *	 DEPRECATED (see below).
87  *
88  *   * - %NETIF_F_RXCSUM
89  *     - Driver (device) performs receive checksum offload.
90  *	 This flag is only used to disable the RX checksum
91  *	 feature for a device. The stack will accept receive
92  *	 checksum indication in packets received on a device
93  *	 regardless of whether NETIF_F_RXCSUM is set.
94  *
95  * Checksumming of received packets by device
96  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
97  *
98  * Indication of checksum verification is set in &sk_buff.ip_summed.
99  * Possible values are:
100  *
101  * - %CHECKSUM_NONE
102  *
103  *   Device did not checksum this packet e.g. due to lack of capabilities.
104  *   The packet contains full (though not verified) checksum in packet but
105  *   not in skb->csum. Thus, skb->csum is undefined in this case.
106  *
107  * - %CHECKSUM_UNNECESSARY
108  *
109  *   The hardware you're dealing with doesn't calculate the full checksum
110  *   (as in %CHECKSUM_COMPLETE), but it does parse headers and verify checksums
111  *   for specific protocols. For such packets it will set %CHECKSUM_UNNECESSARY
112  *   if their checksums are okay. &sk_buff.csum is still undefined in this case
113  *   though. A driver or device must never modify the checksum field in the
114  *   packet even if checksum is verified.
115  *
116  *   %CHECKSUM_UNNECESSARY is applicable to following protocols:
117  *
118  *     - TCP: IPv6 and IPv4.
119  *     - UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
120  *       zero UDP checksum for either IPv4 or IPv6, the networking stack
121  *       may perform further validation in this case.
122  *     - GRE: only if the checksum is present in the header.
123  *     - SCTP: indicates the CRC in SCTP header has been validated.
124  *     - FCOE: indicates the CRC in FC frame has been validated.
125  *
126  *   &sk_buff.csum_level indicates the number of consecutive checksums found in
127  *   the packet minus one that have been verified as %CHECKSUM_UNNECESSARY.
128  *   For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
129  *   and a device is able to verify the checksums for UDP (possibly zero),
130  *   GRE (checksum flag is set) and TCP, &sk_buff.csum_level would be set to
131  *   two. If the device were only able to verify the UDP checksum and not
132  *   GRE, either because it doesn't support GRE checksum or because GRE
133  *   checksum is bad, skb->csum_level would be set to zero (TCP checksum is
134  *   not considered in this case).
135  *
136  * - %CHECKSUM_COMPLETE
137  *
138  *   This is the most generic way. The device supplied checksum of the _whole_
139  *   packet as seen by netif_rx() and fills in &sk_buff.csum. This means the
140  *   hardware doesn't need to parse L3/L4 headers to implement this.
141  *
142  *   Notes:
143  *
144  *   - Even if device supports only some protocols, but is able to produce
145  *     skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
146  *   - CHECKSUM_COMPLETE is not applicable to SCTP and FCoE protocols.
147  *
148  * - %CHECKSUM_PARTIAL
149  *
150  *   A checksum is set up to be offloaded to a device as described in the
151  *   output description for CHECKSUM_PARTIAL. This may occur on a packet
152  *   received directly from another Linux OS, e.g., a virtualized Linux kernel
153  *   on the same host, or it may be set in the input path in GRO or remote
154  *   checksum offload. For the purposes of checksum verification, the checksum
155  *   referred to by skb->csum_start + skb->csum_offset and any preceding
156  *   checksums in the packet are considered verified. Any checksums in the
157  *   packet that are after the checksum being offloaded are not considered to
158  *   be verified.
159  *
160  * Checksumming on transmit for non-GSO
161  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
162  *
163  * The stack requests checksum offload in the &sk_buff.ip_summed for a packet.
164  * Values are:
165  *
166  * - %CHECKSUM_PARTIAL
167  *
168  *   The driver is required to checksum the packet as seen by hard_start_xmit()
169  *   from &sk_buff.csum_start up to the end, and to record/write the checksum at
170  *   offset &sk_buff.csum_start + &sk_buff.csum_offset.
171  *   A driver may verify that the
172  *   csum_start and csum_offset values are valid values given the length and
173  *   offset of the packet, but it should not attempt to validate that the
174  *   checksum refers to a legitimate transport layer checksum -- it is the
175  *   purview of the stack to validate that csum_start and csum_offset are set
176  *   correctly.
177  *
178  *   When the stack requests checksum offload for a packet, the driver MUST
179  *   ensure that the checksum is set correctly. A driver can either offload the
180  *   checksum calculation to the device, or call skb_checksum_help (in the case
181  *   that the device does not support offload for a particular checksum).
182  *
183  *   %NETIF_F_IP_CSUM and %NETIF_F_IPV6_CSUM are being deprecated in favor of
184  *   %NETIF_F_HW_CSUM. New devices should use %NETIF_F_HW_CSUM to indicate
185  *   checksum offload capability.
186  *   skb_csum_hwoffload_help() can be called to resolve %CHECKSUM_PARTIAL based
187  *   on network device checksumming capabilities: if a packet does not match
188  *   them, skb_checksum_help() or skb_crc32c_help() (depending on the value of
189  *   &sk_buff.csum_not_inet, see :ref:`crc`)
190  *   is called to resolve the checksum.
191  *
192  * - %CHECKSUM_NONE
193  *
194  *   The skb was already checksummed by the protocol, or a checksum is not
195  *   required.
196  *
197  * - %CHECKSUM_UNNECESSARY
198  *
199  *   This has the same meaning as CHECKSUM_NONE for checksum offload on
200  *   output.
201  *
202  * - %CHECKSUM_COMPLETE
203  *
204  *   Not used in checksum output. If a driver observes a packet with this value
205  *   set in skbuff, it should treat the packet as if %CHECKSUM_NONE were set.
206  *
207  * .. _crc:
208  *
209  * Non-IP checksum (CRC) offloads
210  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
211  *
212  * .. flat-table::
213  *   :widths: 1 10
214  *
215  *   * - %NETIF_F_SCTP_CRC
216  *     - This feature indicates that a device is capable of
217  *	 offloading the SCTP CRC in a packet. To perform this offload the stack
218  *	 will set csum_start and csum_offset accordingly, set ip_summed to
219  *	 %CHECKSUM_PARTIAL and set csum_not_inet to 1, to provide an indication
220  *	 in the skbuff that the %CHECKSUM_PARTIAL refers to CRC32c.
221  *	 A driver that supports both IP checksum offload and SCTP CRC32c offload
222  *	 must verify which offload is configured for a packet by testing the
223  *	 value of &sk_buff.csum_not_inet; skb_crc32c_csum_help() is provided to
224  *	 resolve %CHECKSUM_PARTIAL on skbs where csum_not_inet is set to 1.
225  *
226  *   * - %NETIF_F_FCOE_CRC
227  *     - This feature indicates that a device is capable of offloading the FCOE
228  *	 CRC in a packet. To perform this offload the stack will set ip_summed
229  *	 to %CHECKSUM_PARTIAL and set csum_start and csum_offset
230  *	 accordingly. Note that there is no indication in the skbuff that the
231  *	 %CHECKSUM_PARTIAL refers to an FCOE checksum, so a driver that supports
232  *	 both IP checksum offload and FCOE CRC offload must verify which offload
233  *	 is configured for a packet, presumably by inspecting packet headers.
234  *
235  * Checksumming on output with GSO
236  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
237  *
238  * In the case of a GSO packet (skb_is_gso() is true), checksum offload
239  * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
240  * gso_type is %SKB_GSO_TCPV4 or %SKB_GSO_TCPV6, TCP checksum offload as
241  * part of the GSO operation is implied. If a checksum is being offloaded
242  * with GSO then ip_summed is %CHECKSUM_PARTIAL, and both csum_start and
243  * csum_offset are set to refer to the outermost checksum being offloaded
244  * (two offloaded checksums are possible with UDP encapsulation).
245  */
246 
247 /* Don't change this without changing skb_csum_unnecessary! */
248 #define CHECKSUM_NONE		0
249 #define CHECKSUM_UNNECESSARY	1
250 #define CHECKSUM_COMPLETE	2
251 #define CHECKSUM_PARTIAL	3
252 
253 /* Maximum value in skb->csum_level */
254 #define SKB_MAX_CSUM_LEVEL	3
255 
256 #define SKB_DATA_ALIGN(X)	ALIGN(X, SMP_CACHE_BYTES)
257 #define SKB_WITH_OVERHEAD(X)	\
258 	((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
259 
260 /* For X bytes available in skb->head, what is the minimal
261  * allocation needed, knowing struct skb_shared_info needs
262  * to be aligned.
263  */
264 #define SKB_HEAD_ALIGN(X) (SKB_DATA_ALIGN(X) + \
265 	SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
266 
267 #define SKB_MAX_ORDER(X, ORDER) \
268 	SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
269 #define SKB_MAX_HEAD(X)		(SKB_MAX_ORDER((X), 0))
270 #define SKB_MAX_ALLOC		(SKB_MAX_ORDER(0, 2))
271 
272 /* return minimum truesize of one skb containing X bytes of data */
273 #define SKB_TRUESIZE(X) ((X) +						\
274 			 SKB_DATA_ALIGN(sizeof(struct sk_buff)) +	\
275 			 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
276 
277 struct net_device;
278 struct scatterlist;
279 struct pipe_inode_info;
280 struct iov_iter;
281 struct napi_struct;
282 struct bpf_prog;
283 union bpf_attr;
284 struct skb_ext;
285 struct ts_config;
286 
287 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
288 struct nf_bridge_info {
289 	enum {
290 		BRNF_PROTO_UNCHANGED,
291 		BRNF_PROTO_8021Q,
292 		BRNF_PROTO_PPPOE
293 	} orig_proto:8;
294 	u8			pkt_otherhost:1;
295 	u8			in_prerouting:1;
296 	u8			bridged_dnat:1;
297 	u8			sabotage_in_done:1;
298 	__u16			frag_max_size;
299 	int			physinif;
300 
301 	/* always valid & non-NULL from FORWARD on, for physdev match */
302 	struct net_device	*physoutdev;
303 	union {
304 		/* prerouting: detect dnat in orig/reply direction */
305 		__be32          ipv4_daddr;
306 		struct in6_addr ipv6_daddr;
307 
308 		/* after prerouting + nat detected: store original source
309 		 * mac since neigh resolution overwrites it, only used while
310 		 * skb is out in neigh layer.
311 		 */
312 		char neigh_header[8];
313 	};
314 };
315 #endif
316 
317 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
318 /* Chain in tc_skb_ext will be used to share the tc chain with
319  * ovs recirc_id. It will be set to the current chain by tc
320  * and read by ovs to recirc_id.
321  */
322 struct tc_skb_ext {
323 	union {
324 		u64 act_miss_cookie;
325 		__u32 chain;
326 	};
327 	__u16 mru;
328 	__u16 zone;
329 	u8 post_ct:1;
330 	u8 post_ct_snat:1;
331 	u8 post_ct_dnat:1;
332 	u8 act_miss:1; /* Set if act_miss_cookie is used */
333 	u8 l2_miss:1; /* Set by bridge upon FDB or MDB miss */
334 };
335 #endif
336 
337 struct sk_buff_head {
338 	/* These two members must be first to match sk_buff. */
339 	struct_group_tagged(sk_buff_list, list,
340 		struct sk_buff	*next;
341 		struct sk_buff	*prev;
342 	);
343 
344 	__u32		qlen;
345 	spinlock_t	lock;
346 };
347 
348 struct sk_buff;
349 
350 #ifndef CONFIG_MAX_SKB_FRAGS
351 # define CONFIG_MAX_SKB_FRAGS 17
352 #endif
353 
354 #define MAX_SKB_FRAGS CONFIG_MAX_SKB_FRAGS
355 
356 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
357  * segment using its current segmentation instead.
358  */
359 #define GSO_BY_FRAGS	0xFFFF
360 
361 typedef struct skb_frag {
362 	netmem_ref netmem;
363 	unsigned int len;
364 	unsigned int offset;
365 } skb_frag_t;
366 
367 /**
368  * skb_frag_size() - Returns the size of a skb fragment
369  * @frag: skb fragment
370  */
371 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
372 {
373 	return frag->len;
374 }
375 
376 /**
377  * skb_frag_size_set() - Sets the size of a skb fragment
378  * @frag: skb fragment
379  * @size: size of fragment
380  */
381 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
382 {
383 	frag->len = size;
384 }
385 
386 /**
387  * skb_frag_size_add() - Increments the size of a skb fragment by @delta
388  * @frag: skb fragment
389  * @delta: value to add
390  */
391 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
392 {
393 	frag->len += delta;
394 }
395 
396 /**
397  * skb_frag_size_sub() - Decrements the size of a skb fragment by @delta
398  * @frag: skb fragment
399  * @delta: value to subtract
400  */
401 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
402 {
403 	frag->len -= delta;
404 }
405 
406 /**
407  * skb_frag_must_loop - Test if %p is a high memory page
408  * @p: fragment's page
409  */
410 static inline bool skb_frag_must_loop(struct page *p)
411 {
412 #if defined(CONFIG_HIGHMEM)
413 	if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) || PageHighMem(p))
414 		return true;
415 #endif
416 	return false;
417 }
418 
419 /**
420  *	skb_frag_foreach_page - loop over pages in a fragment
421  *
422  *	@f:		skb frag to operate on
423  *	@f_off:		offset from start of f->netmem
424  *	@f_len:		length from f_off to loop over
425  *	@p:		(temp var) current page
426  *	@p_off:		(temp var) offset from start of current page,
427  *	                           non-zero only on first page.
428  *	@p_len:		(temp var) length in current page,
429  *				   < PAGE_SIZE only on first and last page.
430  *	@copied:	(temp var) length so far, excluding current p_len.
431  *
432  *	A fragment can hold a compound page, in which case per-page
433  *	operations, notably kmap_atomic, must be called for each
434  *	regular page.
435  */
436 #define skb_frag_foreach_page(f, f_off, f_len, p, p_off, p_len, copied)	\
437 	for (p = skb_frag_page(f) + ((f_off) >> PAGE_SHIFT),		\
438 	     p_off = (f_off) & (PAGE_SIZE - 1),				\
439 	     p_len = skb_frag_must_loop(p) ?				\
440 	     min_t(u32, f_len, PAGE_SIZE - p_off) : f_len,		\
441 	     copied = 0;						\
442 	     copied < f_len;						\
443 	     copied += p_len, p++, p_off = 0,				\
444 	     p_len = min_t(u32, f_len - copied, PAGE_SIZE))		\
445 
446 /**
447  * struct skb_shared_hwtstamps - hardware time stamps
448  * @hwtstamp:		hardware time stamp transformed into duration
449  *			since arbitrary point in time
450  * @netdev_data:	address/cookie of network device driver used as
451  *			reference to actual hardware time stamp
452  *
453  * Software time stamps generated by ktime_get_real() are stored in
454  * skb->tstamp.
455  *
456  * hwtstamps can only be compared against other hwtstamps from
457  * the same device.
458  *
459  * This structure is attached to packets as part of the
460  * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
461  */
462 struct skb_shared_hwtstamps {
463 	union {
464 		ktime_t	hwtstamp;
465 		void *netdev_data;
466 	};
467 };
468 
469 /* Definitions for tx_flags in struct skb_shared_info */
470 enum {
471 	/* generate hardware time stamp */
472 	SKBTX_HW_TSTAMP_NOBPF = 1 << 0,
473 
474 	/* generate software time stamp when queueing packet to NIC */
475 	SKBTX_SW_TSTAMP = 1 << 1,
476 
477 	/* device driver is going to provide hardware time stamp */
478 	SKBTX_IN_PROGRESS = 1 << 2,
479 
480 	/* generate software time stamp on packet tx completion */
481 	SKBTX_COMPLETION_TSTAMP = 1 << 3,
482 
483 	/* determine hardware time stamp based on time or cycles */
484 	SKBTX_HW_TSTAMP_NETDEV = 1 << 5,
485 
486 	/* generate software time stamp when entering packet scheduling */
487 	SKBTX_SCHED_TSTAMP = 1 << 6,
488 
489 	/* used for bpf extension when a bpf program is loaded */
490 	SKBTX_BPF = 1 << 7,
491 };
492 
493 #define SKBTX_HW_TSTAMP		(SKBTX_HW_TSTAMP_NOBPF | SKBTX_BPF)
494 
495 #define SKBTX_ANY_SW_TSTAMP	(SKBTX_SW_TSTAMP    | \
496 				 SKBTX_SCHED_TSTAMP | \
497 				 SKBTX_BPF          | \
498 				 SKBTX_COMPLETION_TSTAMP)
499 #define SKBTX_ANY_TSTAMP	(SKBTX_HW_TSTAMP | \
500 				 SKBTX_ANY_SW_TSTAMP)
501 
502 /* Definitions for flags in struct skb_shared_info */
503 enum {
504 	/* use zcopy routines */
505 	SKBFL_ZEROCOPY_ENABLE = BIT(0),
506 
507 	/* This indicates at least one fragment might be overwritten
508 	 * (as in vmsplice(), sendfile() ...)
509 	 * If we need to compute a TX checksum, we'll need to copy
510 	 * all frags to avoid possible bad checksum
511 	 */
512 	SKBFL_SHARED_FRAG = BIT(1),
513 
514 	/* segment contains only zerocopy data and should not be
515 	 * charged to the kernel memory.
516 	 */
517 	SKBFL_PURE_ZEROCOPY = BIT(2),
518 
519 	SKBFL_DONT_ORPHAN = BIT(3),
520 
521 	/* page references are managed by the ubuf_info, so it's safe to
522 	 * use frags only up until ubuf_info is released
523 	 */
524 	SKBFL_MANAGED_FRAG_REFS = BIT(4),
525 };
526 
527 #define SKBFL_ZEROCOPY_FRAG	(SKBFL_ZEROCOPY_ENABLE | SKBFL_SHARED_FRAG)
528 #define SKBFL_ALL_ZEROCOPY	(SKBFL_ZEROCOPY_FRAG | SKBFL_PURE_ZEROCOPY | \
529 				 SKBFL_DONT_ORPHAN | SKBFL_MANAGED_FRAG_REFS)
530 
531 struct ubuf_info_ops {
532 	void (*complete)(struct sk_buff *, struct ubuf_info *,
533 			 bool zerocopy_success);
534 	/* has to be compatible with skb_zcopy_set() */
535 	int (*link_skb)(struct sk_buff *skb, struct ubuf_info *uarg);
536 };
537 
538 /*
539  * The callback notifies userspace to release buffers when skb DMA is done in
540  * lower device, the skb last reference should be 0 when calling this.
541  * The zerocopy_success argument is true if zero copy transmit occurred,
542  * false on data copy or out of memory error caused by data copy attempt.
543  * The ctx field is used to track device context.
544  * The desc field is used to track userspace buffer index.
545  */
546 struct ubuf_info {
547 	const struct ubuf_info_ops *ops;
548 	refcount_t refcnt;
549 	u8 flags;
550 };
551 
552 struct ubuf_info_msgzc {
553 	struct ubuf_info ubuf;
554 
555 	union {
556 		struct {
557 			unsigned long desc;
558 			void *ctx;
559 		};
560 		struct {
561 			u32 id;
562 			u16 len;
563 			u16 zerocopy:1;
564 			u32 bytelen;
565 		};
566 	};
567 
568 	struct mmpin {
569 		struct user_struct *user;
570 		unsigned int num_pg;
571 	} mmp;
572 };
573 
574 #define skb_uarg(SKB)	((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg))
575 #define uarg_to_msgzc(ubuf_ptr)	container_of((ubuf_ptr), struct ubuf_info_msgzc, \
576 					     ubuf)
577 
578 int mm_account_pinned_pages(struct mmpin *mmp, size_t size);
579 void mm_unaccount_pinned_pages(struct mmpin *mmp);
580 
581 /* Preserve some data across TX submission and completion.
582  *
583  * Note, this state is stored in the driver. Extending the layout
584  * might need some special care.
585  */
586 struct xsk_tx_metadata_compl {
587 	__u64 *tx_timestamp;
588 };
589 
590 /* This data is invariant across clones and lives at
591  * the end of the header data, ie. at skb->end.
592  */
593 struct skb_shared_info {
594 	__u8		flags;
595 	__u8		meta_len;
596 	__u8		nr_frags;
597 	__u8		tx_flags;
598 	unsigned short	gso_size;
599 	/* Warning: this field is not always filled in (UFO)! */
600 	unsigned short	gso_segs;
601 	struct sk_buff	*frag_list;
602 	union {
603 		struct skb_shared_hwtstamps hwtstamps;
604 		struct xsk_tx_metadata_compl xsk_meta;
605 	};
606 	unsigned int	gso_type;
607 	u32		tskey;
608 
609 	/*
610 	 * Warning : all fields before dataref are cleared in __alloc_skb()
611 	 */
612 	atomic_t	dataref;
613 
614 	union {
615 		struct {
616 			u32		xdp_frags_size;
617 			u32		xdp_frags_truesize;
618 		};
619 
620 		/*
621 		 * Intermediate layers must ensure that destructor_arg
622 		 * remains valid until skb destructor.
623 		 */
624 		void		*destructor_arg;
625 	};
626 
627 	/* must be last field, see pskb_expand_head() */
628 	skb_frag_t	frags[MAX_SKB_FRAGS];
629 };
630 
631 /**
632  * DOC: dataref and headerless skbs
633  *
634  * Transport layers send out clones of payload skbs they hold for
635  * retransmissions. To allow lower layers of the stack to prepend their headers
636  * we split &skb_shared_info.dataref into two halves.
637  * The lower 16 bits count the overall number of references.
638  * The higher 16 bits indicate how many of the references are payload-only.
639  * skb_header_cloned() checks if skb is allowed to add / write the headers.
640  *
641  * The creator of the skb (e.g. TCP) marks its skb as &sk_buff.nohdr
642  * (via __skb_header_release()). Any clone created from marked skb will get
643  * &sk_buff.hdr_len populated with the available headroom.
644  * If there's the only clone in existence it's able to modify the headroom
645  * at will. The sequence of calls inside the transport layer is::
646  *
647  *  <alloc skb>
648  *  skb_reserve()
649  *  __skb_header_release()
650  *  skb_clone()
651  *  // send the clone down the stack
652  *
653  * This is not a very generic construct and it depends on the transport layers
654  * doing the right thing. In practice there's usually only one payload-only skb.
655  * Having multiple payload-only skbs with different lengths of hdr_len is not
656  * possible. The payload-only skbs should never leave their owner.
657  */
658 #define SKB_DATAREF_SHIFT 16
659 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
660 
661 
662 enum {
663 	SKB_FCLONE_UNAVAILABLE,	/* skb has no fclone (from head_cache) */
664 	SKB_FCLONE_ORIG,	/* orig skb (from fclone_cache) */
665 	SKB_FCLONE_CLONE,	/* companion fclone skb (from fclone_cache) */
666 };
667 
668 enum {
669 	SKB_GSO_TCPV4 = 1 << 0,
670 
671 	/* This indicates the skb is from an untrusted source. */
672 	SKB_GSO_DODGY = 1 << 1,
673 
674 	/* This indicates the tcp segment has CWR set. */
675 	SKB_GSO_TCP_ECN = 1 << 2,
676 
677 	__SKB_GSO_TCP_FIXEDID = 1 << 3,
678 
679 	SKB_GSO_TCPV6 = 1 << 4,
680 
681 	SKB_GSO_FCOE = 1 << 5,
682 
683 	SKB_GSO_GRE = 1 << 6,
684 
685 	SKB_GSO_GRE_CSUM = 1 << 7,
686 
687 	SKB_GSO_IPXIP4 = 1 << 8,
688 
689 	SKB_GSO_IPXIP6 = 1 << 9,
690 
691 	SKB_GSO_UDP_TUNNEL = 1 << 10,
692 
693 	SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
694 
695 	SKB_GSO_PARTIAL = 1 << 12,
696 
697 	SKB_GSO_TUNNEL_REMCSUM = 1 << 13,
698 
699 	SKB_GSO_SCTP = 1 << 14,
700 
701 	SKB_GSO_ESP = 1 << 15,
702 
703 	SKB_GSO_UDP = 1 << 16,
704 
705 	SKB_GSO_UDP_L4 = 1 << 17,
706 
707 	SKB_GSO_FRAGLIST = 1 << 18,
708 
709 	SKB_GSO_TCP_ACCECN = 1 << 19,
710 
711 	/* These indirectly map onto the same netdev feature.
712 	 * If NETIF_F_TSO_MANGLEID is set it may mangle both inner and outer IDs.
713 	 */
714 	SKB_GSO_TCP_FIXEDID = 1 << 30,
715 	SKB_GSO_TCP_FIXEDID_INNER = 1 << 31,
716 };
717 
718 #if BITS_PER_LONG > 32
719 #define NET_SKBUFF_DATA_USES_OFFSET 1
720 #endif
721 
722 #ifdef NET_SKBUFF_DATA_USES_OFFSET
723 typedef unsigned int sk_buff_data_t;
724 #else
725 typedef unsigned char *sk_buff_data_t;
726 #endif
727 
728 enum skb_tstamp_type {
729 	SKB_CLOCK_REALTIME,
730 	SKB_CLOCK_MONOTONIC,
731 	SKB_CLOCK_TAI,
732 	__SKB_CLOCK_MAX = SKB_CLOCK_TAI,
733 };
734 
735 /**
736  * DOC: Basic sk_buff geometry
737  *
738  * struct sk_buff itself is a metadata structure and does not hold any packet
739  * data. All the data is held in associated buffers.
740  *
741  * &sk_buff.head points to the main "head" buffer. The head buffer is divided
742  * into two parts:
743  *
744  *  - data buffer, containing headers and sometimes payload;
745  *    this is the part of the skb operated on by the common helpers
746  *    such as skb_put() or skb_pull();
747  *  - shared info (struct skb_shared_info) which holds an array of pointers
748  *    to read-only data in the (page, offset, length) format.
749  *
750  * Optionally &skb_shared_info.frag_list may point to another skb.
751  *
752  * Basic diagram may look like this::
753  *
754  *                                  ---------------
755  *                                 | sk_buff       |
756  *                                  ---------------
757  *     ,---------------------------  + head
758  *    /          ,-----------------  + data
759  *   /          /      ,-----------  + tail
760  *  |          |      |            , + end
761  *  |          |      |           |
762  *  v          v      v           v
763  *   -----------------------------------------------
764  *  | headroom | data |  tailroom | skb_shared_info |
765  *   -----------------------------------------------
766  *                                 + [page frag]
767  *                                 + [page frag]
768  *                                 + [page frag]
769  *                                 + [page frag]       ---------
770  *                                 + frag_list    --> | sk_buff |
771  *                                                     ---------
772  *
773  */
774 
775 /**
776  *	struct sk_buff - socket buffer
777  *	@next: Next buffer in list
778  *	@prev: Previous buffer in list
779  *	@tstamp: Time we arrived/left
780  *	@skb_mstamp_ns: (aka @tstamp) earliest departure time; start point
781  *		for retransmit timer
782  *	@rbnode: RB tree node, alternative to next/prev for netem/tcp
783  *	@list: queue head
784  *	@ll_node: anchor in an llist (eg socket defer_list)
785  *	@sk: Socket we are owned by
786  *	@dev: Device we arrived on/are leaving by
787  *	@dev_scratch: (aka @dev) alternate use of @dev when @dev would be %NULL
788  *	@cb: Control buffer. Free for use by every layer. Put private vars here
789  *	@_skb_refdst: destination entry (with norefcount bit)
790  *	@len: Length of actual data
791  *	@data_len: Data length
792  *	@mac_len: Length of link layer header
793  *	@hdr_len: writable header length of cloned skb
794  *	@csum: Checksum (must include start/offset pair)
795  *	@csum_start: Offset from skb->head where checksumming should start
796  *	@csum_offset: Offset from csum_start where checksum should be stored
797  *	@priority: Packet queueing priority
798  *	@ignore_df: allow local fragmentation
799  *	@cloned: Head may be cloned (check refcnt to be sure)
800  *	@ip_summed: Driver fed us an IP checksum
801  *	@nohdr: Payload reference only, must not modify header
802  *	@pkt_type: Packet class
803  *	@fclone: skbuff clone status
804  *	@ipvs_property: skbuff is owned by ipvs
805  *	@inner_protocol_type: whether the inner protocol is
806  *		ENCAP_TYPE_ETHER or ENCAP_TYPE_IPPROTO
807  *	@remcsum_offload: remote checksum offload is enabled
808  *	@offload_fwd_mark: Packet was L2-forwarded in hardware
809  *	@offload_l3_fwd_mark: Packet was L3-forwarded in hardware
810  *	@tc_skip_classify: do not classify packet. set by IFB device
811  *	@tc_at_ingress: used within tc_classify to distinguish in/egress
812  *	@redirected: packet was redirected by packet classifier
813  *	@from_ingress: packet was redirected from the ingress path
814  *	@nf_skip_egress: packet shall skip nf egress - see netfilter_netdev.h
815  *	@peeked: this packet has been seen already, so stats have been
816  *		done for it, don't do them again
817  *	@nf_trace: netfilter packet trace flag
818  *	@protocol: Packet protocol from driver
819  *	@destructor: Destruct function
820  *	@tcp_tsorted_anchor: list structure for TCP (tp->tsorted_sent_queue)
821  *	@_sk_redir: socket redirection information for skmsg
822  *	@_nfct: Associated connection, if any (with nfctinfo bits)
823  *	@skb_iif: ifindex of device we arrived on
824  *	@tc_index: Traffic control index
825  *	@hash: the packet hash
826  *	@queue_mapping: Queue mapping for multiqueue devices
827  *	@head_frag: skb was allocated from page fragments,
828  *		not allocated by kmalloc() or vmalloc().
829  *	@pfmemalloc: skbuff was allocated from PFMEMALLOC reserves
830  *	@pp_recycle: mark the packet for recycling instead of freeing (implies
831  *		page_pool support on driver)
832  *	@active_extensions: active extensions (skb_ext_id types)
833  *	@ndisc_nodetype: router type (from link layer)
834  *	@ooo_okay: allow the mapping of a socket to a queue to be changed
835  *	@l4_hash: indicate hash is a canonical 4-tuple hash over transport
836  *		ports.
837  *	@sw_hash: indicates hash was computed in software stack
838  *	@wifi_acked_valid: wifi_acked was set
839  *	@wifi_acked: whether frame was acked on wifi or not
840  *	@no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
841  *	@encapsulation: indicates the inner headers in the skbuff are valid
842  *	@encap_hdr_csum: software checksum is needed
843  *	@csum_valid: checksum is already valid
844  *	@csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL
845  *	@csum_complete_sw: checksum was completed by software
846  *	@csum_level: indicates the number of consecutive checksums found in
847  *		the packet minus one that have been verified as
848  *		CHECKSUM_UNNECESSARY (max 3)
849  *	@unreadable: indicates that at least 1 of the fragments in this skb is
850  *		unreadable.
851  *	@dst_pending_confirm: need to confirm neighbour
852  *	@decrypted: Decrypted SKB
853  *	@slow_gro: state present at GRO time, slower prepare step required
854  *	@tstamp_type: When set, skb->tstamp has the
855  *		delivery_time clock base of skb->tstamp.
856  *	@napi_id: id of the NAPI struct this skb came from
857  *	@sender_cpu: (aka @napi_id) source CPU in XPS
858  *	@alloc_cpu: CPU which did the skb allocation.
859  *	@secmark: security marking
860  *	@mark: Generic packet mark
861  *	@reserved_tailroom: (aka @mark) number of bytes of free space available
862  *		at the tail of an sk_buff
863  *	@vlan_all: vlan fields (proto & tci)
864  *	@vlan_proto: vlan encapsulation protocol
865  *	@vlan_tci: vlan tag control information
866  *	@inner_protocol: Protocol (encapsulation)
867  *	@inner_ipproto: (aka @inner_protocol) stores ipproto when
868  *		skb->inner_protocol_type == ENCAP_TYPE_IPPROTO;
869  *	@inner_transport_header: Inner transport layer header (encapsulation)
870  *	@inner_network_header: Network layer header (encapsulation)
871  *	@inner_mac_header: Link layer header (encapsulation)
872  *	@transport_header: Transport layer header
873  *	@network_header: Network layer header
874  *	@mac_header: Link layer header
875  *	@kcov_handle: KCOV remote handle for remote coverage collection
876  *	@tail: Tail pointer
877  *	@end: End pointer
878  *	@head: Head of buffer
879  *	@data: Data head pointer
880  *	@truesize: Buffer size
881  *	@users: User count - see {datagram,tcp}.c
882  *	@extensions: allocated extensions, valid if active_extensions is nonzero
883  */
884 
885 struct sk_buff {
886 	union {
887 		struct {
888 			/* These two members must be first to match sk_buff_head. */
889 			struct sk_buff		*next;
890 			struct sk_buff		*prev;
891 
892 			union {
893 				struct net_device	*dev;
894 				/* Some protocols might use this space to store information,
895 				 * while device pointer would be NULL.
896 				 * UDP receive path is one user.
897 				 */
898 				unsigned long		dev_scratch;
899 			};
900 		};
901 		struct rb_node		rbnode; /* used in netem, ip4 defrag, and tcp stack */
902 		struct list_head	list;
903 		struct llist_node	ll_node;
904 	};
905 
906 	struct sock		*sk;
907 
908 	union {
909 		ktime_t		tstamp;
910 		u64		skb_mstamp_ns; /* earliest departure time */
911 	};
912 	/*
913 	 * This is the control buffer. It is free to use for every
914 	 * layer. Please put your private variables there. If you
915 	 * want to keep them across layers you have to do a skb_clone()
916 	 * first. This is owned by whoever has the skb queued ATM.
917 	 */
918 	char			cb[48] __aligned(8);
919 
920 	union {
921 		struct {
922 			unsigned long	_skb_refdst;
923 			void		(*destructor)(struct sk_buff *skb);
924 		};
925 		struct list_head	tcp_tsorted_anchor;
926 #ifdef CONFIG_NET_SOCK_MSG
927 		unsigned long		_sk_redir;
928 #endif
929 	};
930 
931 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
932 	unsigned long		 _nfct;
933 #endif
934 	unsigned int		len,
935 				data_len;
936 	__u16			mac_len,
937 				hdr_len;
938 
939 	/* Following fields are _not_ copied in __copy_skb_header()
940 	 * Note that queue_mapping is here mostly to fill a hole.
941 	 */
942 	__u16			queue_mapping;
943 
944 /* if you move cloned around you also must adapt those constants */
945 #ifdef __BIG_ENDIAN_BITFIELD
946 #define CLONED_MASK	(1 << 7)
947 #else
948 #define CLONED_MASK	1
949 #endif
950 #define CLONED_OFFSET		offsetof(struct sk_buff, __cloned_offset)
951 
952 	/* private: */
953 	__u8			__cloned_offset[0];
954 	/* public: */
955 	__u8			cloned:1,
956 				nohdr:1,
957 				fclone:2,
958 				peeked:1,
959 				head_frag:1,
960 				pfmemalloc:1,
961 				pp_recycle:1; /* page_pool recycle indicator */
962 #ifdef CONFIG_SKB_EXTENSIONS
963 	__u8			active_extensions;
964 #endif
965 
966 	/* Fields enclosed in headers group are copied
967 	 * using a single memcpy() in __copy_skb_header()
968 	 */
969 	struct_group(headers,
970 
971 	/* private: */
972 	__u8			__pkt_type_offset[0];
973 	/* public: */
974 	__u8			pkt_type:3; /* see PKT_TYPE_MAX */
975 	__u8			ignore_df:1;
976 	__u8			dst_pending_confirm:1;
977 	__u8			ip_summed:2;
978 	__u8			ooo_okay:1;
979 
980 	/* private: */
981 	__u8			__mono_tc_offset[0];
982 	/* public: */
983 	__u8			tstamp_type:2;	/* See skb_tstamp_type */
984 #ifdef CONFIG_NET_XGRESS
985 	__u8			tc_at_ingress:1;	/* See TC_AT_INGRESS_MASK */
986 	__u8			tc_skip_classify:1;
987 #endif
988 	__u8			remcsum_offload:1;
989 	__u8			csum_complete_sw:1;
990 	__u8			csum_level:2;
991 	__u8			inner_protocol_type:1;
992 
993 	__u8			l4_hash:1;
994 	__u8			sw_hash:1;
995 #ifdef CONFIG_WIRELESS
996 	__u8			wifi_acked_valid:1;
997 	__u8			wifi_acked:1;
998 #endif
999 	__u8			no_fcs:1;
1000 	/* Indicates the inner headers are valid in the skbuff. */
1001 	__u8			encapsulation:1;
1002 	__u8			encap_hdr_csum:1;
1003 	__u8			csum_valid:1;
1004 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1005 	__u8			ndisc_nodetype:2;
1006 #endif
1007 
1008 #if IS_ENABLED(CONFIG_IP_VS)
1009 	__u8			ipvs_property:1;
1010 #endif
1011 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || IS_ENABLED(CONFIG_NF_TABLES)
1012 	__u8			nf_trace:1;
1013 #endif
1014 #ifdef CONFIG_NET_SWITCHDEV
1015 	__u8			offload_fwd_mark:1;
1016 	__u8			offload_l3_fwd_mark:1;
1017 #endif
1018 	__u8			redirected:1;
1019 #ifdef CONFIG_NET_REDIRECT
1020 	__u8			from_ingress:1;
1021 #endif
1022 #ifdef CONFIG_NETFILTER_SKIP_EGRESS
1023 	__u8			nf_skip_egress:1;
1024 #endif
1025 #ifdef CONFIG_SKB_DECRYPTED
1026 	__u8			decrypted:1;
1027 #endif
1028 	__u8			slow_gro:1;
1029 #if IS_ENABLED(CONFIG_IP_SCTP)
1030 	__u8			csum_not_inet:1;
1031 #endif
1032 	__u8			unreadable:1;
1033 #if defined(CONFIG_NET_SCHED) || defined(CONFIG_NET_XGRESS)
1034 	__u16			tc_index;	/* traffic control index */
1035 #endif
1036 
1037 	u16			alloc_cpu;
1038 
1039 	union {
1040 		__wsum		csum;
1041 		struct {
1042 			__u16	csum_start;
1043 			__u16	csum_offset;
1044 		};
1045 	};
1046 	__u32			priority;
1047 	int			skb_iif;
1048 	__u32			hash;
1049 	union {
1050 		u32		vlan_all;
1051 		struct {
1052 			__be16	vlan_proto;
1053 			__u16	vlan_tci;
1054 		};
1055 	};
1056 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
1057 	union {
1058 		unsigned int	napi_id;
1059 		unsigned int	sender_cpu;
1060 	};
1061 #endif
1062 #ifdef CONFIG_NETWORK_SECMARK
1063 	__u32		secmark;
1064 #endif
1065 
1066 	union {
1067 		__u32		mark;
1068 		__u32		reserved_tailroom;
1069 	};
1070 
1071 	union {
1072 		__be16		inner_protocol;
1073 		__u8		inner_ipproto;
1074 	};
1075 
1076 	__u16			inner_transport_header;
1077 	__u16			inner_network_header;
1078 	__u16			inner_mac_header;
1079 
1080 	__be16			protocol;
1081 	__u16			transport_header;
1082 	__u16			network_header;
1083 	__u16			mac_header;
1084 
1085 #ifdef CONFIG_KCOV
1086 	u64			kcov_handle;
1087 #endif
1088 
1089 	); /* end headers group */
1090 
1091 	/* These elements must be at the end, see alloc_skb() for details.  */
1092 	sk_buff_data_t		tail;
1093 	sk_buff_data_t		end;
1094 	unsigned char		*head,
1095 				*data;
1096 	unsigned int		truesize;
1097 	refcount_t		users;
1098 
1099 #ifdef CONFIG_SKB_EXTENSIONS
1100 	/* only usable after checking ->active_extensions != 0 */
1101 	struct skb_ext		*extensions;
1102 #endif
1103 };
1104 
1105 /* if you move pkt_type around you also must adapt those constants */
1106 #ifdef __BIG_ENDIAN_BITFIELD
1107 #define PKT_TYPE_MAX	(7 << 5)
1108 #else
1109 #define PKT_TYPE_MAX	7
1110 #endif
1111 #define PKT_TYPE_OFFSET		offsetof(struct sk_buff, __pkt_type_offset)
1112 
1113 /* if you move tc_at_ingress or tstamp_type
1114  * around, you also must adapt these constants.
1115  */
1116 #ifdef __BIG_ENDIAN_BITFIELD
1117 #define SKB_TSTAMP_TYPE_MASK		(3 << 6)
1118 #define SKB_TSTAMP_TYPE_RSHIFT		(6)
1119 #define TC_AT_INGRESS_MASK		(1 << 5)
1120 #else
1121 #define SKB_TSTAMP_TYPE_MASK		(3)
1122 #define TC_AT_INGRESS_MASK		(1 << 2)
1123 #endif
1124 #define SKB_BF_MONO_TC_OFFSET		offsetof(struct sk_buff, __mono_tc_offset)
1125 
1126 #ifdef __KERNEL__
1127 /*
1128  *	Handling routines are only of interest to the kernel
1129  */
1130 
1131 #define SKB_ALLOC_FCLONE	0x01
1132 #define SKB_ALLOC_RX		0x02
1133 #define SKB_ALLOC_NAPI		0x04
1134 
1135 /**
1136  * skb_pfmemalloc - Test if the skb was allocated from PFMEMALLOC reserves
1137  * @skb: buffer
1138  */
1139 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
1140 {
1141 	return unlikely(skb->pfmemalloc);
1142 }
1143 
1144 /*
1145  * skb might have a dst pointer attached, refcounted or not.
1146  * _skb_refdst low order bit is set if refcount was _not_ taken
1147  */
1148 #define SKB_DST_NOREF	1UL
1149 #define SKB_DST_PTRMASK	~(SKB_DST_NOREF)
1150 
1151 /**
1152  * skb_dst - returns skb dst_entry
1153  * @skb: buffer
1154  *
1155  * Returns: skb dst_entry, regardless of reference taken or not.
1156  */
1157 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
1158 {
1159 	/* If refdst was not refcounted, check we still are in a
1160 	 * rcu_read_lock section
1161 	 */
1162 	WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
1163 		!rcu_read_lock_held() &&
1164 		!rcu_read_lock_bh_held());
1165 	return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
1166 }
1167 
1168 static inline void skb_dst_check_unset(struct sk_buff *skb)
1169 {
1170 	DEBUG_NET_WARN_ON_ONCE((skb->_skb_refdst & SKB_DST_PTRMASK) &&
1171 			       !(skb->_skb_refdst & SKB_DST_NOREF));
1172 }
1173 
1174 /**
1175  * skb_dstref_steal() - return current dst_entry value and clear it
1176  * @skb: buffer
1177  *
1178  * Resets skb dst_entry without adjusting its reference count. Useful in
1179  * cases where dst_entry needs to be temporarily reset and restored.
1180  * Note that the returned value cannot be used directly because it
1181  * might contain SKB_DST_NOREF bit.
1182  *
1183  * When in doubt, prefer skb_dst_drop() over skb_dstref_steal() to correctly
1184  * handle dst_entry reference counting.
1185  *
1186  * Returns: original skb dst_entry.
1187  */
1188 static inline unsigned long skb_dstref_steal(struct sk_buff *skb)
1189 {
1190 	unsigned long refdst = skb->_skb_refdst;
1191 
1192 	skb->_skb_refdst = 0;
1193 	return refdst;
1194 }
1195 
1196 /**
1197  * skb_dstref_restore() - restore skb dst_entry removed via skb_dstref_steal()
1198  * @skb: buffer
1199  * @refdst: dst entry from a call to skb_dstref_steal()
1200  */
1201 static inline void skb_dstref_restore(struct sk_buff *skb, unsigned long refdst)
1202 {
1203 	skb_dst_check_unset(skb);
1204 	skb->_skb_refdst = refdst;
1205 }
1206 
1207 /**
1208  * skb_dst_set - sets skb dst
1209  * @skb: buffer
1210  * @dst: dst entry
1211  *
1212  * Sets skb dst, assuming a reference was taken on dst and should
1213  * be released by skb_dst_drop()
1214  */
1215 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
1216 {
1217 	skb_dst_check_unset(skb);
1218 	skb->slow_gro |= !!dst;
1219 	skb->_skb_refdst = (unsigned long)dst;
1220 }
1221 
1222 /**
1223  * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
1224  * @skb: buffer
1225  * @dst: dst entry
1226  *
1227  * Sets skb dst, assuming a reference was not taken on dst.
1228  * If dst entry is cached, we do not take reference and dst_release
1229  * will be avoided by refdst_drop. If dst entry is not cached, we take
1230  * reference, so that last dst_release can destroy the dst immediately.
1231  */
1232 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
1233 {
1234 	skb_dst_check_unset(skb);
1235 	WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
1236 	skb->slow_gro |= !!dst;
1237 	skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
1238 }
1239 
1240 /**
1241  * skb_dst_is_noref - Test if skb dst isn't refcounted
1242  * @skb: buffer
1243  */
1244 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
1245 {
1246 	return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
1247 }
1248 
1249 /* For mangling skb->pkt_type from user space side from applications
1250  * such as nft, tc, etc, we only allow a conservative subset of
1251  * possible pkt_types to be set.
1252 */
1253 static inline bool skb_pkt_type_ok(u32 ptype)
1254 {
1255 	return ptype <= PACKET_OTHERHOST;
1256 }
1257 
1258 /**
1259  * skb_napi_id - Returns the skb's NAPI id
1260  * @skb: buffer
1261  */
1262 static inline unsigned int skb_napi_id(const struct sk_buff *skb)
1263 {
1264 #ifdef CONFIG_NET_RX_BUSY_POLL
1265 	return skb->napi_id;
1266 #else
1267 	return 0;
1268 #endif
1269 }
1270 
1271 static inline bool skb_wifi_acked_valid(const struct sk_buff *skb)
1272 {
1273 #ifdef CONFIG_WIRELESS
1274 	return skb->wifi_acked_valid;
1275 #else
1276 	return 0;
1277 #endif
1278 }
1279 
1280 /**
1281  * skb_unref - decrement the skb's reference count
1282  * @skb: buffer
1283  *
1284  * Returns: true if we can free the skb.
1285  */
1286 static inline bool skb_unref(struct sk_buff *skb)
1287 {
1288 	if (unlikely(!skb))
1289 		return false;
1290 	if (!IS_ENABLED(CONFIG_DEBUG_NET) && likely(refcount_read(&skb->users) == 1))
1291 		smp_rmb();
1292 	else if (likely(!refcount_dec_and_test(&skb->users)))
1293 		return false;
1294 
1295 	return true;
1296 }
1297 
1298 static inline bool skb_data_unref(const struct sk_buff *skb,
1299 				  struct skb_shared_info *shinfo)
1300 {
1301 	int bias;
1302 
1303 	if (!skb->cloned)
1304 		return true;
1305 
1306 	bias = skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1;
1307 
1308 	if (atomic_read(&shinfo->dataref) == bias)
1309 		smp_rmb();
1310 	else if (atomic_sub_return(bias, &shinfo->dataref))
1311 		return false;
1312 
1313 	return true;
1314 }
1315 
1316 void __fix_address sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb,
1317 				      enum skb_drop_reason reason);
1318 
1319 static inline void
1320 kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
1321 {
1322 	sk_skb_reason_drop(NULL, skb, reason);
1323 }
1324 
1325 /**
1326  *	kfree_skb - free an sk_buff with 'NOT_SPECIFIED' reason
1327  *	@skb: buffer to free
1328  */
1329 static inline void kfree_skb(struct sk_buff *skb)
1330 {
1331 	kfree_skb_reason(skb, SKB_DROP_REASON_NOT_SPECIFIED);
1332 }
1333 
1334 void skb_release_head_state(struct sk_buff *skb);
1335 void kfree_skb_list_reason(struct sk_buff *segs,
1336 			   enum skb_drop_reason reason);
1337 void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt);
1338 void skb_tx_error(struct sk_buff *skb);
1339 
1340 static inline void kfree_skb_list(struct sk_buff *segs)
1341 {
1342 	kfree_skb_list_reason(segs, SKB_DROP_REASON_NOT_SPECIFIED);
1343 }
1344 
1345 #ifdef CONFIG_TRACEPOINTS
1346 void consume_skb(struct sk_buff *skb);
1347 #else
1348 static inline void consume_skb(struct sk_buff *skb)
1349 {
1350 	return kfree_skb(skb);
1351 }
1352 #endif
1353 
1354 void __consume_stateless_skb(struct sk_buff *skb);
1355 void  __kfree_skb(struct sk_buff *skb);
1356 
1357 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
1358 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
1359 		      bool *fragstolen, int *delta_truesize);
1360 
1361 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
1362 			    int node);
1363 struct sk_buff *__build_skb(void *data, unsigned int frag_size);
1364 struct sk_buff *build_skb(void *data, unsigned int frag_size);
1365 struct sk_buff *build_skb_around(struct sk_buff *skb,
1366 				 void *data, unsigned int frag_size);
1367 void skb_attempt_defer_free(struct sk_buff *skb);
1368 
1369 u32 napi_skb_cache_get_bulk(void **skbs, u32 n);
1370 struct sk_buff *napi_build_skb(void *data, unsigned int frag_size);
1371 struct sk_buff *slab_build_skb(void *data);
1372 
1373 /**
1374  * alloc_skb - allocate a network buffer
1375  * @size: size to allocate
1376  * @priority: allocation mask
1377  *
1378  * This function is a convenient wrapper around __alloc_skb().
1379  */
1380 static inline struct sk_buff *alloc_skb(unsigned int size,
1381 					gfp_t priority)
1382 {
1383 	return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
1384 }
1385 
1386 struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
1387 				     unsigned long data_len,
1388 				     int max_page_order,
1389 				     int *errcode,
1390 				     gfp_t gfp_mask);
1391 struct sk_buff *alloc_skb_for_msg(struct sk_buff *first);
1392 
1393 /* Layout of fast clones : [skb1][skb2][fclone_ref] */
1394 struct sk_buff_fclones {
1395 	struct sk_buff	skb1;
1396 
1397 	struct sk_buff	skb2;
1398 
1399 	refcount_t	fclone_ref;
1400 };
1401 
1402 /**
1403  *	skb_fclone_busy - check if fclone is busy
1404  *	@sk: socket
1405  *	@skb: buffer
1406  *
1407  * Returns: true if skb is a fast clone, and its clone is not freed.
1408  * Some drivers call skb_orphan() in their ndo_start_xmit(),
1409  * so we also check that didn't happen.
1410  */
1411 static inline bool skb_fclone_busy(const struct sock *sk,
1412 				   const struct sk_buff *skb)
1413 {
1414 	const struct sk_buff_fclones *fclones;
1415 
1416 	fclones = container_of(skb, struct sk_buff_fclones, skb1);
1417 
1418 	return skb->fclone == SKB_FCLONE_ORIG &&
1419 	       refcount_read(&fclones->fclone_ref) > 1 &&
1420 	       READ_ONCE(fclones->skb2.sk) == sk;
1421 }
1422 
1423 /**
1424  * alloc_skb_fclone - allocate a network buffer from fclone cache
1425  * @size: size to allocate
1426  * @priority: allocation mask
1427  *
1428  * This function is a convenient wrapper around __alloc_skb().
1429  */
1430 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
1431 					       gfp_t priority)
1432 {
1433 	return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
1434 }
1435 
1436 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
1437 void skb_headers_offset_update(struct sk_buff *skb, int off);
1438 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
1439 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
1440 void skb_copy_header(struct sk_buff *new, const struct sk_buff *old);
1441 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
1442 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1443 				   gfp_t gfp_mask, bool fclone);
1444 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
1445 					  gfp_t gfp_mask)
1446 {
1447 	return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
1448 }
1449 
1450 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
1451 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
1452 				     unsigned int headroom);
1453 struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom);
1454 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
1455 				int newtailroom, gfp_t priority);
1456 int __must_check skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
1457 				     int offset, int len);
1458 int __must_check skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg,
1459 			      int offset, int len);
1460 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
1461 int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error);
1462 
1463 /**
1464  *	skb_pad			-	zero pad the tail of an skb
1465  *	@skb: buffer to pad
1466  *	@pad: space to pad
1467  *
1468  *	Ensure that a buffer is followed by a padding area that is zero
1469  *	filled. Used by network drivers which may DMA or transfer data
1470  *	beyond the buffer end onto the wire.
1471  *
1472  *	May return error in out of memory cases. The skb is freed on error.
1473  */
1474 static inline int skb_pad(struct sk_buff *skb, int pad)
1475 {
1476 	return __skb_pad(skb, pad, true);
1477 }
1478 #define dev_kfree_skb(a)	consume_skb(a)
1479 
1480 int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1481 			 int offset, size_t size, size_t max_frags);
1482 
1483 struct skb_seq_state {
1484 	__u32		lower_offset;
1485 	__u32		upper_offset;
1486 	__u32		frag_idx;
1487 	__u32		stepped_offset;
1488 	struct sk_buff	*root_skb;
1489 	struct sk_buff	*cur_skb;
1490 	__u8		*frag_data;
1491 	__u32		frag_off;
1492 };
1493 
1494 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1495 			  unsigned int to, struct skb_seq_state *st);
1496 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1497 			  struct skb_seq_state *st);
1498 void skb_abort_seq_read(struct skb_seq_state *st);
1499 int skb_copy_seq_read(struct skb_seq_state *st, int offset, void *to, int len);
1500 
1501 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1502 			   unsigned int to, struct ts_config *config);
1503 
1504 /*
1505  * Packet hash types specify the type of hash in skb_set_hash.
1506  *
1507  * Hash types refer to the protocol layer addresses which are used to
1508  * construct a packet's hash. The hashes are used to differentiate or identify
1509  * flows of the protocol layer for the hash type. Hash types are either
1510  * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1511  *
1512  * Properties of hashes:
1513  *
1514  * 1) Two packets in different flows have different hash values
1515  * 2) Two packets in the same flow should have the same hash value
1516  *
1517  * A hash at a higher layer is considered to be more specific. A driver should
1518  * set the most specific hash possible.
1519  *
1520  * A driver cannot indicate a more specific hash than the layer at which a hash
1521  * was computed. For instance an L3 hash cannot be set as an L4 hash.
1522  *
1523  * A driver may indicate a hash level which is less specific than the
1524  * actual layer the hash was computed on. For instance, a hash computed
1525  * at L4 may be considered an L3 hash. This should only be done if the
1526  * driver can't unambiguously determine that the HW computed the hash at
1527  * the higher layer. Note that the "should" in the second property above
1528  * permits this.
1529  */
1530 enum pkt_hash_types {
1531 	PKT_HASH_TYPE_NONE,	/* Undefined type */
1532 	PKT_HASH_TYPE_L2,	/* Input: src_MAC, dest_MAC */
1533 	PKT_HASH_TYPE_L3,	/* Input: src_IP, dst_IP */
1534 	PKT_HASH_TYPE_L4,	/* Input: src_IP, dst_IP, src_port, dst_port */
1535 };
1536 
1537 static inline void skb_clear_hash(struct sk_buff *skb)
1538 {
1539 	skb->hash = 0;
1540 	skb->sw_hash = 0;
1541 	skb->l4_hash = 0;
1542 }
1543 
1544 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1545 {
1546 	if (!skb->l4_hash)
1547 		skb_clear_hash(skb);
1548 }
1549 
1550 static inline void
1551 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1552 {
1553 	skb->l4_hash = is_l4;
1554 	skb->sw_hash = is_sw;
1555 	skb->hash = hash;
1556 }
1557 
1558 static inline void
1559 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1560 {
1561 	/* Used by drivers to set hash from HW */
1562 	__skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1563 }
1564 
1565 static inline void
1566 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1567 {
1568 	__skb_set_hash(skb, hash, true, is_l4);
1569 }
1570 
1571 u32 __skb_get_hash_symmetric_net(const struct net *net, const struct sk_buff *skb);
1572 
1573 static inline u32 __skb_get_hash_symmetric(const struct sk_buff *skb)
1574 {
1575 	return __skb_get_hash_symmetric_net(NULL, skb);
1576 }
1577 
1578 void __skb_get_hash_net(const struct net *net, struct sk_buff *skb);
1579 u32 skb_get_poff(const struct sk_buff *skb);
1580 u32 __skb_get_poff(const struct sk_buff *skb, const void *data,
1581 		   const struct flow_keys_basic *keys, int hlen);
1582 __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1583 			  const void *data, int hlen_proto);
1584 
1585 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1586 			     const struct flow_dissector_key *key,
1587 			     unsigned int key_count);
1588 
1589 struct bpf_flow_dissector;
1590 u32 bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
1591 		     __be16 proto, int nhoff, int hlen, unsigned int flags);
1592 
1593 bool __skb_flow_dissect(const struct net *net,
1594 			const struct sk_buff *skb,
1595 			struct flow_dissector *flow_dissector,
1596 			void *target_container, const void *data,
1597 			__be16 proto, int nhoff, int hlen, unsigned int flags);
1598 
1599 static inline bool skb_flow_dissect(const struct sk_buff *skb,
1600 				    struct flow_dissector *flow_dissector,
1601 				    void *target_container, unsigned int flags)
1602 {
1603 	return __skb_flow_dissect(NULL, skb, flow_dissector,
1604 				  target_container, NULL, 0, 0, 0, flags);
1605 }
1606 
1607 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1608 					      struct flow_keys *flow,
1609 					      unsigned int flags)
1610 {
1611 	memset(flow, 0, sizeof(*flow));
1612 	return __skb_flow_dissect(NULL, skb, &flow_keys_dissector,
1613 				  flow, NULL, 0, 0, 0, flags);
1614 }
1615 
1616 static inline bool
1617 skb_flow_dissect_flow_keys_basic(const struct net *net,
1618 				 const struct sk_buff *skb,
1619 				 struct flow_keys_basic *flow,
1620 				 const void *data, __be16 proto,
1621 				 int nhoff, int hlen, unsigned int flags)
1622 {
1623 	memset(flow, 0, sizeof(*flow));
1624 	return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow,
1625 				  data, proto, nhoff, hlen, flags);
1626 }
1627 
1628 void skb_flow_dissect_meta(const struct sk_buff *skb,
1629 			   struct flow_dissector *flow_dissector,
1630 			   void *target_container);
1631 
1632 /* Gets a skb connection tracking info, ctinfo map should be a
1633  * map of mapsize to translate enum ip_conntrack_info states
1634  * to user states.
1635  */
1636 void
1637 skb_flow_dissect_ct(const struct sk_buff *skb,
1638 		    struct flow_dissector *flow_dissector,
1639 		    void *target_container,
1640 		    u16 *ctinfo_map, size_t mapsize,
1641 		    bool post_ct, u16 zone);
1642 void
1643 skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
1644 			     struct flow_dissector *flow_dissector,
1645 			     void *target_container);
1646 
1647 void skb_flow_dissect_hash(const struct sk_buff *skb,
1648 			   struct flow_dissector *flow_dissector,
1649 			   void *target_container);
1650 
1651 static inline __u32 skb_get_hash_net(const struct net *net, struct sk_buff *skb)
1652 {
1653 	if (!skb->l4_hash && !skb->sw_hash)
1654 		__skb_get_hash_net(net, skb);
1655 
1656 	return skb->hash;
1657 }
1658 
1659 static inline __u32 skb_get_hash(struct sk_buff *skb)
1660 {
1661 	if (!skb->l4_hash && !skb->sw_hash)
1662 		__skb_get_hash_net(NULL, skb);
1663 
1664 	return skb->hash;
1665 }
1666 
1667 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1668 {
1669 	if (!skb->l4_hash && !skb->sw_hash) {
1670 		struct flow_keys keys;
1671 		__u32 hash = __get_hash_from_flowi6(fl6, &keys);
1672 
1673 		__skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1674 	}
1675 
1676 	return skb->hash;
1677 }
1678 
1679 __u32 skb_get_hash_perturb(const struct sk_buff *skb,
1680 			   const siphash_key_t *perturb);
1681 
1682 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1683 {
1684 	return skb->hash;
1685 }
1686 
1687 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1688 {
1689 	to->hash = from->hash;
1690 	to->sw_hash = from->sw_hash;
1691 	to->l4_hash = from->l4_hash;
1692 };
1693 
1694 static inline int skb_cmp_decrypted(const struct sk_buff *skb1,
1695 				    const struct sk_buff *skb2)
1696 {
1697 #ifdef CONFIG_SKB_DECRYPTED
1698 	return skb2->decrypted - skb1->decrypted;
1699 #else
1700 	return 0;
1701 #endif
1702 }
1703 
1704 static inline bool skb_is_decrypted(const struct sk_buff *skb)
1705 {
1706 #ifdef CONFIG_SKB_DECRYPTED
1707 	return skb->decrypted;
1708 #else
1709 	return false;
1710 #endif
1711 }
1712 
1713 static inline void skb_copy_decrypted(struct sk_buff *to,
1714 				      const struct sk_buff *from)
1715 {
1716 #ifdef CONFIG_SKB_DECRYPTED
1717 	to->decrypted = from->decrypted;
1718 #endif
1719 }
1720 
1721 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1722 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1723 {
1724 	return skb->head + skb->end;
1725 }
1726 
1727 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1728 {
1729 	return skb->end;
1730 }
1731 
1732 static inline void skb_set_end_offset(struct sk_buff *skb, unsigned int offset)
1733 {
1734 	skb->end = offset;
1735 }
1736 #else
1737 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1738 {
1739 	return skb->end;
1740 }
1741 
1742 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1743 {
1744 	return skb->end - skb->head;
1745 }
1746 
1747 static inline void skb_set_end_offset(struct sk_buff *skb, unsigned int offset)
1748 {
1749 	skb->end = skb->head + offset;
1750 }
1751 #endif
1752 
1753 extern const struct ubuf_info_ops msg_zerocopy_ubuf_ops;
1754 
1755 struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
1756 				       struct ubuf_info *uarg, bool devmem);
1757 
1758 void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
1759 
1760 struct net_devmem_dmabuf_binding;
1761 
1762 int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
1763 			    struct sk_buff *skb, struct iov_iter *from,
1764 			    size_t length,
1765 			    struct net_devmem_dmabuf_binding *binding);
1766 
1767 int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
1768 				struct iov_iter *from, size_t length);
1769 
1770 static inline int skb_zerocopy_iter_dgram(struct sk_buff *skb,
1771 					  struct msghdr *msg, int len)
1772 {
1773 	return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len,
1774 				       NULL);
1775 }
1776 
1777 int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
1778 			     struct msghdr *msg, int len,
1779 			     struct ubuf_info *uarg,
1780 			     struct net_devmem_dmabuf_binding *binding);
1781 
1782 /* Internal */
1783 #define skb_shinfo(SKB)	((struct skb_shared_info *)(skb_end_pointer(SKB)))
1784 
1785 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1786 {
1787 	return &skb_shinfo(skb)->hwtstamps;
1788 }
1789 
1790 static inline struct ubuf_info *skb_zcopy(struct sk_buff *skb)
1791 {
1792 	bool is_zcopy = skb && skb_shinfo(skb)->flags & SKBFL_ZEROCOPY_ENABLE;
1793 
1794 	return is_zcopy ? skb_uarg(skb) : NULL;
1795 }
1796 
1797 static inline bool skb_zcopy_pure(const struct sk_buff *skb)
1798 {
1799 	return skb_shinfo(skb)->flags & SKBFL_PURE_ZEROCOPY;
1800 }
1801 
1802 static inline bool skb_zcopy_managed(const struct sk_buff *skb)
1803 {
1804 	return skb_shinfo(skb)->flags & SKBFL_MANAGED_FRAG_REFS;
1805 }
1806 
1807 static inline bool skb_pure_zcopy_same(const struct sk_buff *skb1,
1808 				       const struct sk_buff *skb2)
1809 {
1810 	return skb_zcopy_pure(skb1) == skb_zcopy_pure(skb2);
1811 }
1812 
1813 static inline void net_zcopy_get(struct ubuf_info *uarg)
1814 {
1815 	refcount_inc(&uarg->refcnt);
1816 }
1817 
1818 static inline void skb_zcopy_init(struct sk_buff *skb, struct ubuf_info *uarg)
1819 {
1820 	skb_shinfo(skb)->destructor_arg = uarg;
1821 	skb_shinfo(skb)->flags |= uarg->flags;
1822 }
1823 
1824 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg,
1825 				 bool *have_ref)
1826 {
1827 	if (skb && uarg && !skb_zcopy(skb)) {
1828 		if (unlikely(have_ref && *have_ref))
1829 			*have_ref = false;
1830 		else
1831 			net_zcopy_get(uarg);
1832 		skb_zcopy_init(skb, uarg);
1833 	}
1834 }
1835 
1836 static inline void skb_zcopy_set_nouarg(struct sk_buff *skb, void *val)
1837 {
1838 	skb_shinfo(skb)->destructor_arg = (void *)((uintptr_t) val | 0x1UL);
1839 	skb_shinfo(skb)->flags |= SKBFL_ZEROCOPY_FRAG;
1840 }
1841 
1842 static inline bool skb_zcopy_is_nouarg(struct sk_buff *skb)
1843 {
1844 	return (uintptr_t) skb_shinfo(skb)->destructor_arg & 0x1UL;
1845 }
1846 
1847 static inline void *skb_zcopy_get_nouarg(struct sk_buff *skb)
1848 {
1849 	return (void *)((uintptr_t) skb_shinfo(skb)->destructor_arg & ~0x1UL);
1850 }
1851 
1852 static inline void net_zcopy_put(struct ubuf_info *uarg)
1853 {
1854 	if (uarg)
1855 		uarg->ops->complete(NULL, uarg, true);
1856 }
1857 
1858 static inline void net_zcopy_put_abort(struct ubuf_info *uarg, bool have_uref)
1859 {
1860 	if (uarg) {
1861 		if (uarg->ops == &msg_zerocopy_ubuf_ops)
1862 			msg_zerocopy_put_abort(uarg, have_uref);
1863 		else if (have_uref)
1864 			net_zcopy_put(uarg);
1865 	}
1866 }
1867 
1868 /* Release a reference on a zerocopy structure */
1869 static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy_success)
1870 {
1871 	struct ubuf_info *uarg = skb_zcopy(skb);
1872 
1873 	if (uarg) {
1874 		if (!skb_zcopy_is_nouarg(skb))
1875 			uarg->ops->complete(skb, uarg, zerocopy_success);
1876 
1877 		skb_shinfo(skb)->flags &= ~SKBFL_ALL_ZEROCOPY;
1878 	}
1879 }
1880 
1881 void __skb_zcopy_downgrade_managed(struct sk_buff *skb);
1882 
1883 static inline void skb_zcopy_downgrade_managed(struct sk_buff *skb)
1884 {
1885 	if (unlikely(skb_zcopy_managed(skb)))
1886 		__skb_zcopy_downgrade_managed(skb);
1887 }
1888 
1889 /* Return true if frags in this skb are readable by the host. */
1890 static inline bool skb_frags_readable(const struct sk_buff *skb)
1891 {
1892 	return !skb->unreadable;
1893 }
1894 
1895 static inline void skb_mark_not_on_list(struct sk_buff *skb)
1896 {
1897 	skb->next = NULL;
1898 }
1899 
1900 static inline void skb_poison_list(struct sk_buff *skb)
1901 {
1902 #ifdef CONFIG_DEBUG_NET
1903 	skb->next = SKB_LIST_POISON_NEXT;
1904 #endif
1905 }
1906 
1907 /* Iterate through singly-linked GSO fragments of an skb. */
1908 #define skb_list_walk_safe(first, skb, next_skb)                               \
1909 	for ((skb) = (first), (next_skb) = (skb) ? (skb)->next : NULL; (skb);  \
1910 	     (skb) = (next_skb), (next_skb) = (skb) ? (skb)->next : NULL)
1911 
1912 static inline void skb_list_del_init(struct sk_buff *skb)
1913 {
1914 	__list_del_entry(&skb->list);
1915 	skb_mark_not_on_list(skb);
1916 }
1917 
1918 /**
1919  *	skb_queue_empty - check if a queue is empty
1920  *	@list: queue head
1921  *
1922  *	Returns true if the queue is empty, false otherwise.
1923  */
1924 static inline int skb_queue_empty(const struct sk_buff_head *list)
1925 {
1926 	return list->next == (const struct sk_buff *) list;
1927 }
1928 
1929 /**
1930  *	skb_queue_empty_lockless - check if a queue is empty
1931  *	@list: queue head
1932  *
1933  *	Returns true if the queue is empty, false otherwise.
1934  *	This variant can be used in lockless contexts.
1935  */
1936 static inline bool skb_queue_empty_lockless(const struct sk_buff_head *list)
1937 {
1938 	return READ_ONCE(list->next) == (const struct sk_buff *) list;
1939 }
1940 
1941 
1942 /**
1943  *	skb_queue_is_last - check if skb is the last entry in the queue
1944  *	@list: queue head
1945  *	@skb: buffer
1946  *
1947  *	Returns true if @skb is the last buffer on the list.
1948  */
1949 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1950 				     const struct sk_buff *skb)
1951 {
1952 	return skb->next == (const struct sk_buff *) list;
1953 }
1954 
1955 /**
1956  *	skb_queue_is_first - check if skb is the first entry in the queue
1957  *	@list: queue head
1958  *	@skb: buffer
1959  *
1960  *	Returns true if @skb is the first buffer on the list.
1961  */
1962 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1963 				      const struct sk_buff *skb)
1964 {
1965 	return skb->prev == (const struct sk_buff *) list;
1966 }
1967 
1968 /**
1969  *	skb_queue_next - return the next packet in the queue
1970  *	@list: queue head
1971  *	@skb: current buffer
1972  *
1973  *	Return the next packet in @list after @skb.  It is only valid to
1974  *	call this if skb_queue_is_last() evaluates to false.
1975  */
1976 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1977 					     const struct sk_buff *skb)
1978 {
1979 	/* This BUG_ON may seem severe, but if we just return then we
1980 	 * are going to dereference garbage.
1981 	 */
1982 	BUG_ON(skb_queue_is_last(list, skb));
1983 	return skb->next;
1984 }
1985 
1986 /**
1987  *	skb_queue_prev - return the prev packet in the queue
1988  *	@list: queue head
1989  *	@skb: current buffer
1990  *
1991  *	Return the prev packet in @list before @skb.  It is only valid to
1992  *	call this if skb_queue_is_first() evaluates to false.
1993  */
1994 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1995 					     const struct sk_buff *skb)
1996 {
1997 	/* This BUG_ON may seem severe, but if we just return then we
1998 	 * are going to dereference garbage.
1999 	 */
2000 	BUG_ON(skb_queue_is_first(list, skb));
2001 	return skb->prev;
2002 }
2003 
2004 /**
2005  *	skb_get - reference buffer
2006  *	@skb: buffer to reference
2007  *
2008  *	Makes another reference to a socket buffer and returns a pointer
2009  *	to the buffer.
2010  */
2011 static inline struct sk_buff *skb_get(struct sk_buff *skb)
2012 {
2013 	refcount_inc(&skb->users);
2014 	return skb;
2015 }
2016 
2017 /*
2018  * If users == 1, we are the only owner and can avoid redundant atomic changes.
2019  */
2020 
2021 /**
2022  *	skb_cloned - is the buffer a clone
2023  *	@skb: buffer to check
2024  *
2025  *	Returns true if the buffer was generated with skb_clone() and is
2026  *	one of multiple shared copies of the buffer. Cloned buffers are
2027  *	shared data so must not be written to under normal circumstances.
2028  */
2029 static inline int skb_cloned(const struct sk_buff *skb)
2030 {
2031 	return skb->cloned &&
2032 	       (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
2033 }
2034 
2035 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
2036 {
2037 	might_sleep_if(gfpflags_allow_blocking(pri));
2038 
2039 	if (skb_cloned(skb))
2040 		return pskb_expand_head(skb, 0, 0, pri);
2041 
2042 	return 0;
2043 }
2044 
2045 /* This variant of skb_unclone() makes sure skb->truesize
2046  * and skb_end_offset() are not changed, whenever a new skb->head is needed.
2047  *
2048  * Indeed there is no guarantee that ksize(kmalloc(X)) == ksize(kmalloc(X))
2049  * when various debugging features are in place.
2050  */
2051 int __skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri);
2052 static inline int skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri)
2053 {
2054 	might_sleep_if(gfpflags_allow_blocking(pri));
2055 
2056 	if (skb_cloned(skb))
2057 		return __skb_unclone_keeptruesize(skb, pri);
2058 	return 0;
2059 }
2060 
2061 /**
2062  *	skb_header_cloned - is the header a clone
2063  *	@skb: buffer to check
2064  *
2065  *	Returns true if modifying the header part of the buffer requires
2066  *	the data to be copied.
2067  */
2068 static inline int skb_header_cloned(const struct sk_buff *skb)
2069 {
2070 	int dataref;
2071 
2072 	if (!skb->cloned)
2073 		return 0;
2074 
2075 	dataref = atomic_read(&skb_shinfo(skb)->dataref);
2076 	dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
2077 	return dataref != 1;
2078 }
2079 
2080 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
2081 {
2082 	might_sleep_if(gfpflags_allow_blocking(pri));
2083 
2084 	if (skb_header_cloned(skb))
2085 		return pskb_expand_head(skb, 0, 0, pri);
2086 
2087 	return 0;
2088 }
2089 
2090 /**
2091  * __skb_header_release() - allow clones to use the headroom
2092  * @skb: buffer to operate on
2093  *
2094  * See "DOC: dataref and headerless skbs".
2095  */
2096 static inline void __skb_header_release(struct sk_buff *skb)
2097 {
2098 	skb->nohdr = 1;
2099 	atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
2100 }
2101 
2102 
2103 /**
2104  *	skb_shared - is the buffer shared
2105  *	@skb: buffer to check
2106  *
2107  *	Returns true if more than one person has a reference to this
2108  *	buffer.
2109  */
2110 static inline int skb_shared(const struct sk_buff *skb)
2111 {
2112 	return refcount_read(&skb->users) != 1;
2113 }
2114 
2115 /**
2116  *	skb_share_check - check if buffer is shared and if so clone it
2117  *	@skb: buffer to check
2118  *	@pri: priority for memory allocation
2119  *
2120  *	If the buffer is shared the buffer is cloned and the old copy
2121  *	drops a reference. A new clone with a single reference is returned.
2122  *	If the buffer is not shared the original buffer is returned. When
2123  *	being called from interrupt status or with spinlocks held pri must
2124  *	be GFP_ATOMIC.
2125  *
2126  *	NULL is returned on a memory allocation failure.
2127  */
2128 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
2129 {
2130 	might_sleep_if(gfpflags_allow_blocking(pri));
2131 	if (skb_shared(skb)) {
2132 		struct sk_buff *nskb = skb_clone(skb, pri);
2133 
2134 		if (likely(nskb))
2135 			consume_skb(skb);
2136 		else
2137 			kfree_skb(skb);
2138 		skb = nskb;
2139 	}
2140 	return skb;
2141 }
2142 
2143 /*
2144  *	Copy shared buffers into a new sk_buff. We effectively do COW on
2145  *	packets to handle cases where we have a local reader and forward
2146  *	and a couple of other messy ones. The normal one is tcpdumping
2147  *	a packet that's being forwarded.
2148  */
2149 
2150 /**
2151  *	skb_unshare - make a copy of a shared buffer
2152  *	@skb: buffer to check
2153  *	@pri: priority for memory allocation
2154  *
2155  *	If the socket buffer is a clone then this function creates a new
2156  *	copy of the data, drops a reference count on the old copy and returns
2157  *	the new copy with the reference count at 1. If the buffer is not a clone
2158  *	the original buffer is returned. When called with a spinlock held or
2159  *	from interrupt state @pri must be %GFP_ATOMIC
2160  *
2161  *	%NULL is returned on a memory allocation failure.
2162  */
2163 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
2164 					  gfp_t pri)
2165 {
2166 	might_sleep_if(gfpflags_allow_blocking(pri));
2167 	if (skb_cloned(skb)) {
2168 		struct sk_buff *nskb = skb_copy(skb, pri);
2169 
2170 		/* Free our shared copy */
2171 		if (likely(nskb))
2172 			consume_skb(skb);
2173 		else
2174 			kfree_skb(skb);
2175 		skb = nskb;
2176 	}
2177 	return skb;
2178 }
2179 
2180 /**
2181  *	skb_peek - peek at the head of an &sk_buff_head
2182  *	@list_: list to peek at
2183  *
2184  *	Peek an &sk_buff. Unlike most other operations you _MUST_
2185  *	be careful with this one. A peek leaves the buffer on the
2186  *	list and someone else may run off with it. You must hold
2187  *	the appropriate locks or have a private queue to do this.
2188  *
2189  *	Returns %NULL for an empty list or a pointer to the head element.
2190  *	The reference count is not incremented and the reference is therefore
2191  *	volatile. Use with caution.
2192  */
2193 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
2194 {
2195 	struct sk_buff *skb = list_->next;
2196 
2197 	if (skb == (struct sk_buff *)list_)
2198 		skb = NULL;
2199 	return skb;
2200 }
2201 
2202 /**
2203  *	__skb_peek - peek at the head of a non-empty &sk_buff_head
2204  *	@list_: list to peek at
2205  *
2206  *	Like skb_peek(), but the caller knows that the list is not empty.
2207  */
2208 static inline struct sk_buff *__skb_peek(const struct sk_buff_head *list_)
2209 {
2210 	return list_->next;
2211 }
2212 
2213 /**
2214  *	skb_peek_next - peek skb following the given one from a queue
2215  *	@skb: skb to start from
2216  *	@list_: list to peek at
2217  *
2218  *	Returns %NULL when the end of the list is met or a pointer to the
2219  *	next element. The reference count is not incremented and the
2220  *	reference is therefore volatile. Use with caution.
2221  */
2222 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
2223 		const struct sk_buff_head *list_)
2224 {
2225 	struct sk_buff *next = skb->next;
2226 
2227 	if (next == (struct sk_buff *)list_)
2228 		next = NULL;
2229 	return next;
2230 }
2231 
2232 /**
2233  *	skb_peek_tail - peek at the tail of an &sk_buff_head
2234  *	@list_: list to peek at
2235  *
2236  *	Peek an &sk_buff. Unlike most other operations you _MUST_
2237  *	be careful with this one. A peek leaves the buffer on the
2238  *	list and someone else may run off with it. You must hold
2239  *	the appropriate locks or have a private queue to do this.
2240  *
2241  *	Returns %NULL for an empty list or a pointer to the tail element.
2242  *	The reference count is not incremented and the reference is therefore
2243  *	volatile. Use with caution.
2244  */
2245 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
2246 {
2247 	struct sk_buff *skb = READ_ONCE(list_->prev);
2248 
2249 	if (skb == (struct sk_buff *)list_)
2250 		skb = NULL;
2251 	return skb;
2252 
2253 }
2254 
2255 /**
2256  *	skb_queue_len	- get queue length
2257  *	@list_: list to measure
2258  *
2259  *	Return the length of an &sk_buff queue.
2260  */
2261 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
2262 {
2263 	return list_->qlen;
2264 }
2265 
2266 /**
2267  *	skb_queue_len_lockless	- get queue length
2268  *	@list_: list to measure
2269  *
2270  *	Return the length of an &sk_buff queue.
2271  *	This variant can be used in lockless contexts.
2272  */
2273 static inline __u32 skb_queue_len_lockless(const struct sk_buff_head *list_)
2274 {
2275 	return READ_ONCE(list_->qlen);
2276 }
2277 
2278 /**
2279  *	__skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
2280  *	@list: queue to initialize
2281  *
2282  *	This initializes only the list and queue length aspects of
2283  *	an sk_buff_head object.  This allows to initialize the list
2284  *	aspects of an sk_buff_head without reinitializing things like
2285  *	the spinlock.  It can also be used for on-stack sk_buff_head
2286  *	objects where the spinlock is known to not be used.
2287  */
2288 static inline void __skb_queue_head_init(struct sk_buff_head *list)
2289 {
2290 	list->prev = list->next = (struct sk_buff *)list;
2291 	list->qlen = 0;
2292 }
2293 
2294 /*
2295  * This function creates a split out lock class for each invocation;
2296  * this is needed for now since a whole lot of users of the skb-queue
2297  * infrastructure in drivers have different locking usage (in hardirq)
2298  * than the networking core (in softirq only). In the long run either the
2299  * network layer or drivers should need annotation to consolidate the
2300  * main types of usage into 3 classes.
2301  */
2302 static inline void skb_queue_head_init(struct sk_buff_head *list)
2303 {
2304 	spin_lock_init(&list->lock);
2305 	__skb_queue_head_init(list);
2306 }
2307 
2308 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
2309 		struct lock_class_key *class)
2310 {
2311 	skb_queue_head_init(list);
2312 	lockdep_set_class(&list->lock, class);
2313 }
2314 
2315 /*
2316  *	Insert an sk_buff on a list.
2317  *
2318  *	The "__skb_xxxx()" functions are the non-atomic ones that
2319  *	can only be called with interrupts disabled.
2320  */
2321 static inline void __skb_insert(struct sk_buff *newsk,
2322 				struct sk_buff *prev, struct sk_buff *next,
2323 				struct sk_buff_head *list)
2324 {
2325 	/* See skb_queue_empty_lockless() and skb_peek_tail()
2326 	 * for the opposite READ_ONCE()
2327 	 */
2328 	WRITE_ONCE(newsk->next, next);
2329 	WRITE_ONCE(newsk->prev, prev);
2330 	WRITE_ONCE(((struct sk_buff_list *)next)->prev, newsk);
2331 	WRITE_ONCE(((struct sk_buff_list *)prev)->next, newsk);
2332 	WRITE_ONCE(list->qlen, list->qlen + 1);
2333 }
2334 
2335 static inline void __skb_queue_splice(const struct sk_buff_head *list,
2336 				      struct sk_buff *prev,
2337 				      struct sk_buff *next)
2338 {
2339 	struct sk_buff *first = list->next;
2340 	struct sk_buff *last = list->prev;
2341 
2342 	WRITE_ONCE(first->prev, prev);
2343 	WRITE_ONCE(prev->next, first);
2344 
2345 	WRITE_ONCE(last->next, next);
2346 	WRITE_ONCE(next->prev, last);
2347 }
2348 
2349 /**
2350  *	skb_queue_splice - join two skb lists, this is designed for stacks
2351  *	@list: the new list to add
2352  *	@head: the place to add it in the first list
2353  */
2354 static inline void skb_queue_splice(const struct sk_buff_head *list,
2355 				    struct sk_buff_head *head)
2356 {
2357 	if (!skb_queue_empty(list)) {
2358 		__skb_queue_splice(list, (struct sk_buff *) head, head->next);
2359 		head->qlen += list->qlen;
2360 	}
2361 }
2362 
2363 /**
2364  *	skb_queue_splice_init - join two skb lists and reinitialise the emptied list
2365  *	@list: the new list to add
2366  *	@head: the place to add it in the first list
2367  *
2368  *	The list at @list is reinitialised
2369  */
2370 static inline void skb_queue_splice_init(struct sk_buff_head *list,
2371 					 struct sk_buff_head *head)
2372 {
2373 	if (!skb_queue_empty(list)) {
2374 		__skb_queue_splice(list, (struct sk_buff *) head, head->next);
2375 		head->qlen += list->qlen;
2376 		__skb_queue_head_init(list);
2377 	}
2378 }
2379 
2380 /**
2381  *	skb_queue_splice_tail - join two skb lists, each list being a queue
2382  *	@list: the new list to add
2383  *	@head: the place to add it in the first list
2384  */
2385 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
2386 					 struct sk_buff_head *head)
2387 {
2388 	if (!skb_queue_empty(list)) {
2389 		__skb_queue_splice(list, head->prev, (struct sk_buff *) head);
2390 		head->qlen += list->qlen;
2391 	}
2392 }
2393 
2394 /**
2395  *	skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
2396  *	@list: the new list to add
2397  *	@head: the place to add it in the first list
2398  *
2399  *	Each of the lists is a queue.
2400  *	The list at @list is reinitialised
2401  */
2402 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
2403 					      struct sk_buff_head *head)
2404 {
2405 	if (!skb_queue_empty(list)) {
2406 		__skb_queue_splice(list, head->prev, (struct sk_buff *) head);
2407 		head->qlen += list->qlen;
2408 		__skb_queue_head_init(list);
2409 	}
2410 }
2411 
2412 /**
2413  *	__skb_queue_after - queue a buffer at the list head
2414  *	@list: list to use
2415  *	@prev: place after this buffer
2416  *	@newsk: buffer to queue
2417  *
2418  *	Queue a buffer int the middle of a list. This function takes no locks
2419  *	and you must therefore hold required locks before calling it.
2420  *
2421  *	A buffer cannot be placed on two lists at the same time.
2422  */
2423 static inline void __skb_queue_after(struct sk_buff_head *list,
2424 				     struct sk_buff *prev,
2425 				     struct sk_buff *newsk)
2426 {
2427 	__skb_insert(newsk, prev, ((struct sk_buff_list *)prev)->next, list);
2428 }
2429 
2430 void skb_append(struct sk_buff *old, struct sk_buff *newsk,
2431 		struct sk_buff_head *list);
2432 
2433 static inline void __skb_queue_before(struct sk_buff_head *list,
2434 				      struct sk_buff *next,
2435 				      struct sk_buff *newsk)
2436 {
2437 	__skb_insert(newsk, ((struct sk_buff_list *)next)->prev, next, list);
2438 }
2439 
2440 /**
2441  *	__skb_queue_head - queue a buffer at the list head
2442  *	@list: list to use
2443  *	@newsk: buffer to queue
2444  *
2445  *	Queue a buffer at the start of a list. This function takes no locks
2446  *	and you must therefore hold required locks before calling it.
2447  *
2448  *	A buffer cannot be placed on two lists at the same time.
2449  */
2450 static inline void __skb_queue_head(struct sk_buff_head *list,
2451 				    struct sk_buff *newsk)
2452 {
2453 	__skb_queue_after(list, (struct sk_buff *)list, newsk);
2454 }
2455 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
2456 
2457 /**
2458  *	__skb_queue_tail - queue a buffer at the list tail
2459  *	@list: list to use
2460  *	@newsk: buffer to queue
2461  *
2462  *	Queue a buffer at the end of a list. This function takes no locks
2463  *	and you must therefore hold required locks before calling it.
2464  *
2465  *	A buffer cannot be placed on two lists at the same time.
2466  */
2467 static inline void __skb_queue_tail(struct sk_buff_head *list,
2468 				   struct sk_buff *newsk)
2469 {
2470 	__skb_queue_before(list, (struct sk_buff *)list, newsk);
2471 }
2472 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
2473 
2474 /*
2475  * remove sk_buff from list. _Must_ be called atomically, and with
2476  * the list known..
2477  */
2478 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
2479 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
2480 {
2481 	struct sk_buff *next, *prev;
2482 
2483 	WRITE_ONCE(list->qlen, list->qlen - 1);
2484 	next	   = skb->next;
2485 	prev	   = skb->prev;
2486 	skb->next  = skb->prev = NULL;
2487 	WRITE_ONCE(next->prev, prev);
2488 	WRITE_ONCE(prev->next, next);
2489 }
2490 
2491 /**
2492  *	__skb_dequeue - remove from the head of the queue
2493  *	@list: list to dequeue from
2494  *
2495  *	Remove the head of the list. This function does not take any locks
2496  *	so must be used with appropriate locks held only. The head item is
2497  *	returned or %NULL if the list is empty.
2498  */
2499 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
2500 {
2501 	struct sk_buff *skb = skb_peek(list);
2502 	if (skb)
2503 		__skb_unlink(skb, list);
2504 	return skb;
2505 }
2506 struct sk_buff *skb_dequeue(struct sk_buff_head *list);
2507 
2508 /**
2509  *	__skb_dequeue_tail - remove from the tail of the queue
2510  *	@list: list to dequeue from
2511  *
2512  *	Remove the tail of the list. This function does not take any locks
2513  *	so must be used with appropriate locks held only. The tail item is
2514  *	returned or %NULL if the list is empty.
2515  */
2516 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
2517 {
2518 	struct sk_buff *skb = skb_peek_tail(list);
2519 	if (skb)
2520 		__skb_unlink(skb, list);
2521 	return skb;
2522 }
2523 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
2524 
2525 
2526 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
2527 {
2528 	return skb->data_len;
2529 }
2530 
2531 static inline unsigned int skb_headlen(const struct sk_buff *skb)
2532 {
2533 	return skb->len - skb->data_len;
2534 }
2535 
2536 static inline unsigned int __skb_pagelen(const struct sk_buff *skb)
2537 {
2538 	unsigned int i, len = 0;
2539 
2540 	for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--)
2541 		len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
2542 	return len;
2543 }
2544 
2545 static inline unsigned int skb_pagelen(const struct sk_buff *skb)
2546 {
2547 	return skb_headlen(skb) + __skb_pagelen(skb);
2548 }
2549 
2550 static inline void skb_frag_fill_netmem_desc(skb_frag_t *frag,
2551 					     netmem_ref netmem, int off,
2552 					     int size)
2553 {
2554 	frag->netmem = netmem;
2555 	frag->offset = off;
2556 	skb_frag_size_set(frag, size);
2557 }
2558 
2559 static inline void skb_frag_fill_page_desc(skb_frag_t *frag,
2560 					   struct page *page,
2561 					   int off, int size)
2562 {
2563 	skb_frag_fill_netmem_desc(frag, page_to_netmem(page), off, size);
2564 }
2565 
2566 static inline void __skb_fill_netmem_desc_noacc(struct skb_shared_info *shinfo,
2567 						int i, netmem_ref netmem,
2568 						int off, int size)
2569 {
2570 	skb_frag_t *frag = &shinfo->frags[i];
2571 
2572 	skb_frag_fill_netmem_desc(frag, netmem, off, size);
2573 }
2574 
2575 static inline void __skb_fill_page_desc_noacc(struct skb_shared_info *shinfo,
2576 					      int i, struct page *page,
2577 					      int off, int size)
2578 {
2579 	__skb_fill_netmem_desc_noacc(shinfo, i, page_to_netmem(page), off,
2580 				     size);
2581 }
2582 
2583 /**
2584  * skb_len_add - adds a number to len fields of skb
2585  * @skb: buffer to add len to
2586  * @delta: number of bytes to add
2587  */
2588 static inline void skb_len_add(struct sk_buff *skb, int delta)
2589 {
2590 	skb->len += delta;
2591 	skb->data_len += delta;
2592 	skb->truesize += delta;
2593 }
2594 
2595 /**
2596  * __skb_fill_netmem_desc - initialise a fragment in an skb
2597  * @skb: buffer containing fragment to be initialised
2598  * @i: fragment index to initialise
2599  * @netmem: the netmem to use for this fragment
2600  * @off: the offset to the data with @page
2601  * @size: the length of the data
2602  *
2603  * Initialises the @i'th fragment of @skb to point to &size bytes at
2604  * offset @off within @page.
2605  *
2606  * Does not take any additional reference on the fragment.
2607  */
2608 static inline void __skb_fill_netmem_desc(struct sk_buff *skb, int i,
2609 					  netmem_ref netmem, int off, int size)
2610 {
2611 	struct page *page;
2612 
2613 	__skb_fill_netmem_desc_noacc(skb_shinfo(skb), i, netmem, off, size);
2614 
2615 	if (netmem_is_net_iov(netmem)) {
2616 		skb->unreadable = true;
2617 		return;
2618 	}
2619 
2620 	page = netmem_to_page(netmem);
2621 
2622 	/* Propagate page pfmemalloc to the skb if we can. The problem is
2623 	 * that not all callers have unique ownership of the page but rely
2624 	 * on page_is_pfmemalloc doing the right thing(tm).
2625 	 */
2626 	page = compound_head(page);
2627 	if (page_is_pfmemalloc(page))
2628 		skb->pfmemalloc = true;
2629 }
2630 
2631 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
2632 					struct page *page, int off, int size)
2633 {
2634 	__skb_fill_netmem_desc(skb, i, page_to_netmem(page), off, size);
2635 }
2636 
2637 static inline void skb_fill_netmem_desc(struct sk_buff *skb, int i,
2638 					netmem_ref netmem, int off, int size)
2639 {
2640 	__skb_fill_netmem_desc(skb, i, netmem, off, size);
2641 	skb_shinfo(skb)->nr_frags = i + 1;
2642 }
2643 
2644 /**
2645  * skb_fill_page_desc - initialise a paged fragment in an skb
2646  * @skb: buffer containing fragment to be initialised
2647  * @i: paged fragment index to initialise
2648  * @page: the page to use for this fragment
2649  * @off: the offset to the data with @page
2650  * @size: the length of the data
2651  *
2652  * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
2653  * @skb to point to @size bytes at offset @off within @page. In
2654  * addition updates @skb such that @i is the last fragment.
2655  *
2656  * Does not take any additional reference on the fragment.
2657  */
2658 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
2659 				      struct page *page, int off, int size)
2660 {
2661 	skb_fill_netmem_desc(skb, i, page_to_netmem(page), off, size);
2662 }
2663 
2664 /**
2665  * skb_fill_page_desc_noacc - initialise a paged fragment in an skb
2666  * @skb: buffer containing fragment to be initialised
2667  * @i: paged fragment index to initialise
2668  * @page: the page to use for this fragment
2669  * @off: the offset to the data with @page
2670  * @size: the length of the data
2671  *
2672  * Variant of skb_fill_page_desc() which does not deal with
2673  * pfmemalloc, if page is not owned by us.
2674  */
2675 static inline void skb_fill_page_desc_noacc(struct sk_buff *skb, int i,
2676 					    struct page *page, int off,
2677 					    int size)
2678 {
2679 	struct skb_shared_info *shinfo = skb_shinfo(skb);
2680 
2681 	__skb_fill_page_desc_noacc(shinfo, i, page, off, size);
2682 	shinfo->nr_frags = i + 1;
2683 }
2684 
2685 void skb_add_rx_frag_netmem(struct sk_buff *skb, int i, netmem_ref netmem,
2686 			    int off, int size, unsigned int truesize);
2687 
2688 static inline void skb_add_rx_frag(struct sk_buff *skb, int i,
2689 				   struct page *page, int off, int size,
2690 				   unsigned int truesize)
2691 {
2692 	skb_add_rx_frag_netmem(skb, i, page_to_netmem(page), off, size,
2693 			       truesize);
2694 }
2695 
2696 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
2697 			  unsigned int truesize);
2698 
2699 #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
2700 
2701 #ifdef NET_SKBUFF_DATA_USES_OFFSET
2702 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2703 {
2704 	return skb->head + skb->tail;
2705 }
2706 
2707 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2708 {
2709 	skb->tail = skb->data - skb->head;
2710 }
2711 
2712 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2713 {
2714 	skb_reset_tail_pointer(skb);
2715 	skb->tail += offset;
2716 }
2717 
2718 #else /* NET_SKBUFF_DATA_USES_OFFSET */
2719 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
2720 {
2721 	return skb->tail;
2722 }
2723 
2724 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
2725 {
2726 	skb->tail = skb->data;
2727 }
2728 
2729 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
2730 {
2731 	skb->tail = skb->data + offset;
2732 }
2733 
2734 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
2735 
2736 static inline void skb_assert_len(struct sk_buff *skb)
2737 {
2738 #ifdef CONFIG_DEBUG_NET
2739 	if (WARN_ONCE(!skb->len, "%s\n", __func__))
2740 		DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false);
2741 #endif /* CONFIG_DEBUG_NET */
2742 }
2743 
2744 #if defined(CONFIG_FAIL_SKB_REALLOC)
2745 void skb_might_realloc(struct sk_buff *skb);
2746 #else
2747 static inline void skb_might_realloc(struct sk_buff *skb) {}
2748 #endif
2749 
2750 /*
2751  *	Add data to an sk_buff
2752  */
2753 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
2754 void *skb_put(struct sk_buff *skb, unsigned int len);
2755 static inline void *__skb_put(struct sk_buff *skb, unsigned int len)
2756 {
2757 	void *tmp = skb_tail_pointer(skb);
2758 	SKB_LINEAR_ASSERT(skb);
2759 	skb->tail += len;
2760 	skb->len  += len;
2761 	return tmp;
2762 }
2763 
2764 static inline void *__skb_put_zero(struct sk_buff *skb, unsigned int len)
2765 {
2766 	void *tmp = __skb_put(skb, len);
2767 
2768 	memset(tmp, 0, len);
2769 	return tmp;
2770 }
2771 
2772 static inline void *__skb_put_data(struct sk_buff *skb, const void *data,
2773 				   unsigned int len)
2774 {
2775 	void *tmp = __skb_put(skb, len);
2776 
2777 	memcpy(tmp, data, len);
2778 	return tmp;
2779 }
2780 
2781 static inline void __skb_put_u8(struct sk_buff *skb, u8 val)
2782 {
2783 	*(u8 *)__skb_put(skb, 1) = val;
2784 }
2785 
2786 static inline void *skb_put_zero(struct sk_buff *skb, unsigned int len)
2787 {
2788 	void *tmp = skb_put(skb, len);
2789 
2790 	memset(tmp, 0, len);
2791 
2792 	return tmp;
2793 }
2794 
2795 static inline void *skb_put_data(struct sk_buff *skb, const void *data,
2796 				 unsigned int len)
2797 {
2798 	void *tmp = skb_put(skb, len);
2799 
2800 	memcpy(tmp, data, len);
2801 
2802 	return tmp;
2803 }
2804 
2805 static inline void skb_put_u8(struct sk_buff *skb, u8 val)
2806 {
2807 	*(u8 *)skb_put(skb, 1) = val;
2808 }
2809 
2810 void *skb_push(struct sk_buff *skb, unsigned int len);
2811 static inline void *__skb_push(struct sk_buff *skb, unsigned int len)
2812 {
2813 	DEBUG_NET_WARN_ON_ONCE(len > INT_MAX);
2814 
2815 	skb->data -= len;
2816 	skb->len  += len;
2817 	return skb->data;
2818 }
2819 
2820 void *skb_pull(struct sk_buff *skb, unsigned int len);
2821 static inline void *__skb_pull(struct sk_buff *skb, unsigned int len)
2822 {
2823 	DEBUG_NET_WARN_ON_ONCE(len > INT_MAX);
2824 
2825 	skb->len -= len;
2826 	if (unlikely(skb->len < skb->data_len)) {
2827 #if defined(CONFIG_DEBUG_NET)
2828 		skb->len += len;
2829 		pr_err("__skb_pull(len=%u)\n", len);
2830 		skb_dump(KERN_ERR, skb, false);
2831 #endif
2832 		BUG();
2833 	}
2834 	return skb->data += len;
2835 }
2836 
2837 static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len)
2838 {
2839 	return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
2840 }
2841 
2842 void *skb_pull_data(struct sk_buff *skb, size_t len);
2843 
2844 void *__pskb_pull_tail(struct sk_buff *skb, int delta);
2845 
2846 static inline enum skb_drop_reason
2847 pskb_may_pull_reason(struct sk_buff *skb, unsigned int len)
2848 {
2849 	DEBUG_NET_WARN_ON_ONCE(len > INT_MAX);
2850 	skb_might_realloc(skb);
2851 
2852 	if (likely(len <= skb_headlen(skb)))
2853 		return SKB_NOT_DROPPED_YET;
2854 
2855 	if (unlikely(len > skb->len))
2856 		return SKB_DROP_REASON_PKT_TOO_SMALL;
2857 
2858 	if (unlikely(!__pskb_pull_tail(skb, len - skb_headlen(skb))))
2859 		return SKB_DROP_REASON_NOMEM;
2860 
2861 	return SKB_NOT_DROPPED_YET;
2862 }
2863 
2864 static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
2865 {
2866 	return pskb_may_pull_reason(skb, len) == SKB_NOT_DROPPED_YET;
2867 }
2868 
2869 static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
2870 {
2871 	if (!pskb_may_pull(skb, len))
2872 		return NULL;
2873 
2874 	skb->len -= len;
2875 	return skb->data += len;
2876 }
2877 
2878 void skb_condense(struct sk_buff *skb);
2879 
2880 /**
2881  *	skb_headroom - bytes at buffer head
2882  *	@skb: buffer to check
2883  *
2884  *	Return the number of bytes of free space at the head of an &sk_buff.
2885  */
2886 static inline unsigned int skb_headroom(const struct sk_buff *skb)
2887 {
2888 	return skb->data - skb->head;
2889 }
2890 
2891 /**
2892  *	skb_tailroom - bytes at buffer end
2893  *	@skb: buffer to check
2894  *
2895  *	Return the number of bytes of free space at the tail of an sk_buff
2896  */
2897 static inline int skb_tailroom(const struct sk_buff *skb)
2898 {
2899 	return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
2900 }
2901 
2902 /**
2903  *	skb_availroom - bytes at buffer end
2904  *	@skb: buffer to check
2905  *
2906  *	Return the number of bytes of free space at the tail of an sk_buff
2907  *	allocated by sk_stream_alloc()
2908  */
2909 static inline int skb_availroom(const struct sk_buff *skb)
2910 {
2911 	if (skb_is_nonlinear(skb))
2912 		return 0;
2913 
2914 	return skb->end - skb->tail - skb->reserved_tailroom;
2915 }
2916 
2917 /**
2918  *	skb_reserve - adjust headroom
2919  *	@skb: buffer to alter
2920  *	@len: bytes to move
2921  *
2922  *	Increase the headroom of an empty &sk_buff by reducing the tail
2923  *	room. This is only allowed for an empty buffer.
2924  */
2925 static inline void skb_reserve(struct sk_buff *skb, int len)
2926 {
2927 	skb->data += len;
2928 	skb->tail += len;
2929 }
2930 
2931 /**
2932  *	skb_tailroom_reserve - adjust reserved_tailroom
2933  *	@skb: buffer to alter
2934  *	@mtu: maximum amount of headlen permitted
2935  *	@needed_tailroom: minimum amount of reserved_tailroom
2936  *
2937  *	Set reserved_tailroom so that headlen can be as large as possible but
2938  *	not larger than mtu and tailroom cannot be smaller than
2939  *	needed_tailroom.
2940  *	The required headroom should already have been reserved before using
2941  *	this function.
2942  */
2943 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2944 					unsigned int needed_tailroom)
2945 {
2946 	SKB_LINEAR_ASSERT(skb);
2947 	if (mtu < skb_tailroom(skb) - needed_tailroom)
2948 		/* use at most mtu */
2949 		skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2950 	else
2951 		/* use up to all available space */
2952 		skb->reserved_tailroom = needed_tailroom;
2953 }
2954 
2955 #define ENCAP_TYPE_ETHER	0
2956 #define ENCAP_TYPE_IPPROTO	1
2957 
2958 static inline void skb_set_inner_protocol(struct sk_buff *skb,
2959 					  __be16 protocol)
2960 {
2961 	skb->inner_protocol = protocol;
2962 	skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2963 }
2964 
2965 static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2966 					 __u8 ipproto)
2967 {
2968 	skb->inner_ipproto = ipproto;
2969 	skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2970 }
2971 
2972 static inline void skb_reset_inner_headers(struct sk_buff *skb)
2973 {
2974 	skb->inner_mac_header = skb->mac_header;
2975 	skb->inner_network_header = skb->network_header;
2976 	skb->inner_transport_header = skb->transport_header;
2977 }
2978 
2979 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2980 {
2981 	return skb->mac_header != (typeof(skb->mac_header))~0U;
2982 }
2983 
2984 static inline void skb_reset_mac_len(struct sk_buff *skb)
2985 {
2986 	if (!skb_mac_header_was_set(skb)) {
2987 		DEBUG_NET_WARN_ON_ONCE(1);
2988 		skb->mac_len = 0;
2989 	} else {
2990 		skb->mac_len = skb->network_header - skb->mac_header;
2991 	}
2992 }
2993 
2994 static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2995 							*skb)
2996 {
2997 	return skb->head + skb->inner_transport_header;
2998 }
2999 
3000 static inline int skb_inner_transport_offset(const struct sk_buff *skb)
3001 {
3002 	return skb_inner_transport_header(skb) - skb->data;
3003 }
3004 
3005 static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
3006 {
3007 	long offset = skb->data - skb->head;
3008 
3009 	DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->inner_transport_header))offset);
3010 	skb->inner_transport_header = offset;
3011 }
3012 
3013 static inline void skb_set_inner_transport_header(struct sk_buff *skb,
3014 						   const int offset)
3015 {
3016 	skb_reset_inner_transport_header(skb);
3017 	skb->inner_transport_header += offset;
3018 }
3019 
3020 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
3021 {
3022 	return skb->head + skb->inner_network_header;
3023 }
3024 
3025 static inline void skb_reset_inner_network_header(struct sk_buff *skb)
3026 {
3027 	long offset = skb->data - skb->head;
3028 
3029 	DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->inner_network_header))offset);
3030 	skb->inner_network_header = offset;
3031 }
3032 
3033 static inline void skb_set_inner_network_header(struct sk_buff *skb,
3034 						const int offset)
3035 {
3036 	skb_reset_inner_network_header(skb);
3037 	skb->inner_network_header += offset;
3038 }
3039 
3040 static inline bool skb_inner_network_header_was_set(const struct sk_buff *skb)
3041 {
3042 	return skb->inner_network_header > 0;
3043 }
3044 
3045 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
3046 {
3047 	return skb->head + skb->inner_mac_header;
3048 }
3049 
3050 static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
3051 {
3052 	long offset = skb->data - skb->head;
3053 
3054 	DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->inner_mac_header))offset);
3055 	skb->inner_mac_header = offset;
3056 }
3057 
3058 static inline void skb_set_inner_mac_header(struct sk_buff *skb,
3059 					    const int offset)
3060 {
3061 	skb_reset_inner_mac_header(skb);
3062 	skb->inner_mac_header += offset;
3063 }
3064 static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
3065 {
3066 	return skb->transport_header != (typeof(skb->transport_header))~0U;
3067 }
3068 
3069 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
3070 {
3071 	DEBUG_NET_WARN_ON_ONCE(!skb_transport_header_was_set(skb));
3072 	return skb->head + skb->transport_header;
3073 }
3074 
3075 static inline void skb_reset_transport_header(struct sk_buff *skb)
3076 {
3077 	long offset = skb->data - skb->head;
3078 
3079 	DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->transport_header))offset);
3080 	skb->transport_header = offset;
3081 }
3082 
3083 /**
3084  * skb_reset_transport_header_careful - conditionally reset transport header
3085  * @skb: buffer to alter
3086  *
3087  * Hardened version of skb_reset_transport_header().
3088  *
3089  * Returns: true if the operation was a success.
3090  */
3091 static inline bool __must_check
3092 skb_reset_transport_header_careful(struct sk_buff *skb)
3093 {
3094 	long offset = skb->data - skb->head;
3095 
3096 	if (unlikely(offset != (typeof(skb->transport_header))offset))
3097 		return false;
3098 
3099 	if (unlikely(offset == (typeof(skb->transport_header))~0U))
3100 		return false;
3101 
3102 	skb->transport_header = offset;
3103 	return true;
3104 }
3105 
3106 static inline void skb_set_transport_header(struct sk_buff *skb,
3107 					    const int offset)
3108 {
3109 	skb_reset_transport_header(skb);
3110 	skb->transport_header += offset;
3111 }
3112 
3113 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
3114 {
3115 	return skb->head + skb->network_header;
3116 }
3117 
3118 static inline void skb_reset_network_header(struct sk_buff *skb)
3119 {
3120 	long offset = skb->data - skb->head;
3121 
3122 	DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->network_header))offset);
3123 	skb->network_header = offset;
3124 }
3125 
3126 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
3127 {
3128 	skb_reset_network_header(skb);
3129 	skb->network_header += offset;
3130 }
3131 
3132 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
3133 {
3134 	DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
3135 	return skb->head + skb->mac_header;
3136 }
3137 
3138 static inline int skb_mac_offset(const struct sk_buff *skb)
3139 {
3140 	return skb_mac_header(skb) - skb->data;
3141 }
3142 
3143 static inline u32 skb_mac_header_len(const struct sk_buff *skb)
3144 {
3145 	DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
3146 	return skb->network_header - skb->mac_header;
3147 }
3148 
3149 static inline void skb_unset_mac_header(struct sk_buff *skb)
3150 {
3151 	skb->mac_header = (typeof(skb->mac_header))~0U;
3152 }
3153 
3154 static inline void skb_reset_mac_header(struct sk_buff *skb)
3155 {
3156 	long offset = skb->data - skb->head;
3157 
3158 	DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->mac_header))offset);
3159 	skb->mac_header = offset;
3160 }
3161 
3162 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
3163 {
3164 	skb_reset_mac_header(skb);
3165 	skb->mac_header += offset;
3166 }
3167 
3168 static inline void skb_pop_mac_header(struct sk_buff *skb)
3169 {
3170 	skb->mac_header = skb->network_header;
3171 }
3172 
3173 static inline void skb_probe_transport_header(struct sk_buff *skb)
3174 {
3175 	struct flow_keys_basic keys;
3176 
3177 	if (skb_transport_header_was_set(skb))
3178 		return;
3179 
3180 	if (skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
3181 					     NULL, 0, 0, 0, 0))
3182 		skb_set_transport_header(skb, keys.control.thoff);
3183 }
3184 
3185 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
3186 {
3187 	if (skb_mac_header_was_set(skb)) {
3188 		const unsigned char *old_mac = skb_mac_header(skb);
3189 
3190 		skb_set_mac_header(skb, -skb->mac_len);
3191 		memmove(skb_mac_header(skb), old_mac, skb->mac_len);
3192 	}
3193 }
3194 
3195 /* Move the full mac header up to current network_header.
3196  * Leaves skb->data pointing at offset skb->mac_len into the mac_header.
3197  * Must be provided the complete mac header length.
3198  */
3199 static inline void skb_mac_header_rebuild_full(struct sk_buff *skb, u32 full_mac_len)
3200 {
3201 	if (skb_mac_header_was_set(skb)) {
3202 		const unsigned char *old_mac = skb_mac_header(skb);
3203 
3204 		skb_set_mac_header(skb, -full_mac_len);
3205 		memmove(skb_mac_header(skb), old_mac, full_mac_len);
3206 		__skb_push(skb, full_mac_len - skb->mac_len);
3207 	}
3208 }
3209 
3210 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
3211 {
3212 	return skb->csum_start - skb_headroom(skb);
3213 }
3214 
3215 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
3216 {
3217 	return skb->head + skb->csum_start;
3218 }
3219 
3220 static inline int skb_transport_offset(const struct sk_buff *skb)
3221 {
3222 	return skb_transport_header(skb) - skb->data;
3223 }
3224 
3225 static inline u32 skb_network_header_len(const struct sk_buff *skb)
3226 {
3227 	DEBUG_NET_WARN_ON_ONCE(!skb_transport_header_was_set(skb));
3228 	return skb->transport_header - skb->network_header;
3229 }
3230 
3231 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
3232 {
3233 	return skb->inner_transport_header - skb->inner_network_header;
3234 }
3235 
3236 static inline int skb_network_offset(const struct sk_buff *skb)
3237 {
3238 	return skb_network_header(skb) - skb->data;
3239 }
3240 
3241 static inline int skb_inner_network_offset(const struct sk_buff *skb)
3242 {
3243 	return skb_inner_network_header(skb) - skb->data;
3244 }
3245 
3246 static inline enum skb_drop_reason
3247 pskb_network_may_pull_reason(struct sk_buff *skb, unsigned int len)
3248 {
3249 	return pskb_may_pull_reason(skb, skb_network_offset(skb) + len);
3250 }
3251 
3252 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
3253 {
3254 	return pskb_network_may_pull_reason(skb, len) == SKB_NOT_DROPPED_YET;
3255 }
3256 
3257 /*
3258  * CPUs often take a performance hit when accessing unaligned memory
3259  * locations. The actual performance hit varies, it can be small if the
3260  * hardware handles it or large if we have to take an exception and fix it
3261  * in software.
3262  *
3263  * Since an ethernet header is 14 bytes network drivers often end up with
3264  * the IP header at an unaligned offset. The IP header can be aligned by
3265  * shifting the start of the packet by 2 bytes. Drivers should do this
3266  * with:
3267  *
3268  * skb_reserve(skb, NET_IP_ALIGN);
3269  *
3270  * The downside to this alignment of the IP header is that the DMA is now
3271  * unaligned. On some architectures the cost of an unaligned DMA is high
3272  * and this cost outweighs the gains made by aligning the IP header.
3273  *
3274  * Since this trade off varies between architectures, we allow NET_IP_ALIGN
3275  * to be overridden.
3276  */
3277 #ifndef NET_IP_ALIGN
3278 #define NET_IP_ALIGN	2
3279 #endif
3280 
3281 /*
3282  * The networking layer reserves some headroom in skb data (via
3283  * dev_alloc_skb). This is used to avoid having to reallocate skb data when
3284  * the header has to grow. In the default case, if the header has to grow
3285  * 32 bytes or less we avoid the reallocation.
3286  *
3287  * Unfortunately this headroom changes the DMA alignment of the resulting
3288  * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
3289  * on some architectures. An architecture can override this value,
3290  * perhaps setting it to a cacheline in size (since that will maintain
3291  * cacheline alignment of the DMA). It must be a power of 2.
3292  *
3293  * Various parts of the networking layer expect at least 32 bytes of
3294  * headroom, you should not reduce this.
3295  *
3296  * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
3297  * to reduce average number of cache lines per packet.
3298  * get_rps_cpu() for example only access one 64 bytes aligned block :
3299  * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
3300  */
3301 #ifndef NET_SKB_PAD
3302 #define NET_SKB_PAD	max(32, L1_CACHE_BYTES)
3303 #endif
3304 
3305 int ___pskb_trim(struct sk_buff *skb, unsigned int len);
3306 
3307 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
3308 {
3309 	if (WARN_ON(skb_is_nonlinear(skb)))
3310 		return;
3311 	skb->len = len;
3312 	skb_set_tail_pointer(skb, len);
3313 }
3314 
3315 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
3316 {
3317 	__skb_set_length(skb, len);
3318 }
3319 
3320 void skb_trim(struct sk_buff *skb, unsigned int len);
3321 
3322 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
3323 {
3324 	if (skb->data_len)
3325 		return ___pskb_trim(skb, len);
3326 	__skb_trim(skb, len);
3327 	return 0;
3328 }
3329 
3330 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
3331 {
3332 	skb_might_realloc(skb);
3333 	return (len < skb->len) ? __pskb_trim(skb, len) : 0;
3334 }
3335 
3336 /**
3337  *	pskb_trim_unique - remove end from a paged unique (not cloned) buffer
3338  *	@skb: buffer to alter
3339  *	@len: new length
3340  *
3341  *	This is identical to pskb_trim except that the caller knows that
3342  *	the skb is not cloned so we should never get an error due to out-
3343  *	of-memory.
3344  */
3345 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
3346 {
3347 	int err = pskb_trim(skb, len);
3348 	BUG_ON(err);
3349 }
3350 
3351 static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
3352 {
3353 	unsigned int diff = len - skb->len;
3354 
3355 	if (skb_tailroom(skb) < diff) {
3356 		int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
3357 					   GFP_ATOMIC);
3358 		if (ret)
3359 			return ret;
3360 	}
3361 	__skb_set_length(skb, len);
3362 	return 0;
3363 }
3364 
3365 /**
3366  *	skb_orphan - orphan a buffer
3367  *	@skb: buffer to orphan
3368  *
3369  *	If a buffer currently has an owner then we call the owner's
3370  *	destructor function and make the @skb unowned. The buffer continues
3371  *	to exist but is no longer charged to its former owner.
3372  */
3373 static inline void skb_orphan(struct sk_buff *skb)
3374 {
3375 	if (skb->destructor) {
3376 		skb->destructor(skb);
3377 		skb->destructor = NULL;
3378 		skb->sk		= NULL;
3379 	} else {
3380 		BUG_ON(skb->sk);
3381 	}
3382 }
3383 
3384 /**
3385  *	skb_orphan_frags - orphan the frags contained in a buffer
3386  *	@skb: buffer to orphan frags from
3387  *	@gfp_mask: allocation mask for replacement pages
3388  *
3389  *	For each frag in the SKB which needs a destructor (i.e. has an
3390  *	owner) create a copy of that frag and release the original
3391  *	page by calling the destructor.
3392  */
3393 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
3394 {
3395 	if (likely(!skb_zcopy(skb)))
3396 		return 0;
3397 	if (skb_shinfo(skb)->flags & SKBFL_DONT_ORPHAN)
3398 		return 0;
3399 	return skb_copy_ubufs(skb, gfp_mask);
3400 }
3401 
3402 /* Frags must be orphaned, even if refcounted, if skb might loop to rx path */
3403 static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask)
3404 {
3405 	if (likely(!skb_zcopy(skb)))
3406 		return 0;
3407 	return skb_copy_ubufs(skb, gfp_mask);
3408 }
3409 
3410 /**
3411  *	__skb_queue_purge_reason - empty a list
3412  *	@list: list to empty
3413  *	@reason: drop reason
3414  *
3415  *	Delete all buffers on an &sk_buff list. Each buffer is removed from
3416  *	the list and one reference dropped. This function does not take the
3417  *	list lock and the caller must hold the relevant locks to use it.
3418  */
3419 static inline void __skb_queue_purge_reason(struct sk_buff_head *list,
3420 					    enum skb_drop_reason reason)
3421 {
3422 	struct sk_buff *skb;
3423 
3424 	while ((skb = __skb_dequeue(list)) != NULL)
3425 		kfree_skb_reason(skb, reason);
3426 }
3427 
3428 static inline void __skb_queue_purge(struct sk_buff_head *list)
3429 {
3430 	__skb_queue_purge_reason(list, SKB_DROP_REASON_QUEUE_PURGE);
3431 }
3432 
3433 void skb_queue_purge_reason(struct sk_buff_head *list,
3434 			    enum skb_drop_reason reason);
3435 
3436 static inline void skb_queue_purge(struct sk_buff_head *list)
3437 {
3438 	skb_queue_purge_reason(list, SKB_DROP_REASON_QUEUE_PURGE);
3439 }
3440 
3441 unsigned int skb_rbtree_purge(struct rb_root *root);
3442 void skb_errqueue_purge(struct sk_buff_head *list);
3443 
3444 void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask);
3445 
3446 /**
3447  * netdev_alloc_frag - allocate a page fragment
3448  * @fragsz: fragment size
3449  *
3450  * Allocates a frag from a page for receive buffer.
3451  * Uses GFP_ATOMIC allocations.
3452  */
3453 static inline void *netdev_alloc_frag(unsigned int fragsz)
3454 {
3455 	return __netdev_alloc_frag_align(fragsz, ~0u);
3456 }
3457 
3458 static inline void *netdev_alloc_frag_align(unsigned int fragsz,
3459 					    unsigned int align)
3460 {
3461 	WARN_ON_ONCE(!is_power_of_2(align));
3462 	return __netdev_alloc_frag_align(fragsz, -align);
3463 }
3464 
3465 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
3466 				   gfp_t gfp_mask);
3467 
3468 /**
3469  *	netdev_alloc_skb - allocate an skbuff for rx on a specific device
3470  *	@dev: network device to receive on
3471  *	@length: length to allocate
3472  *
3473  *	Allocate a new &sk_buff and assign it a usage count of one. The
3474  *	buffer has unspecified headroom built in. Users should allocate
3475  *	the headroom they think they need without accounting for the
3476  *	built in space. The built in space is used for optimisations.
3477  *
3478  *	%NULL is returned if there is no free memory. Although this function
3479  *	allocates memory it can be called from an interrupt.
3480  */
3481 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
3482 					       unsigned int length)
3483 {
3484 	return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
3485 }
3486 
3487 /* legacy helper around __netdev_alloc_skb() */
3488 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
3489 					      gfp_t gfp_mask)
3490 {
3491 	return __netdev_alloc_skb(NULL, length, gfp_mask);
3492 }
3493 
3494 /* legacy helper around netdev_alloc_skb() */
3495 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
3496 {
3497 	return netdev_alloc_skb(NULL, length);
3498 }
3499 
3500 
3501 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
3502 		unsigned int length, gfp_t gfp)
3503 {
3504 	struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
3505 
3506 	if (NET_IP_ALIGN && skb)
3507 		skb_reserve(skb, NET_IP_ALIGN);
3508 	return skb;
3509 }
3510 
3511 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
3512 		unsigned int length)
3513 {
3514 	return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
3515 }
3516 
3517 static inline void skb_free_frag(void *addr)
3518 {
3519 	page_frag_free(addr);
3520 }
3521 
3522 void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask);
3523 
3524 static inline void *napi_alloc_frag(unsigned int fragsz)
3525 {
3526 	return __napi_alloc_frag_align(fragsz, ~0u);
3527 }
3528 
3529 static inline void *napi_alloc_frag_align(unsigned int fragsz,
3530 					  unsigned int align)
3531 {
3532 	WARN_ON_ONCE(!is_power_of_2(align));
3533 	return __napi_alloc_frag_align(fragsz, -align);
3534 }
3535 
3536 struct sk_buff *napi_alloc_skb(struct napi_struct *napi, unsigned int length);
3537 void napi_consume_skb(struct sk_buff *skb, int budget);
3538 
3539 void napi_skb_free_stolen_head(struct sk_buff *skb);
3540 void __napi_kfree_skb(struct sk_buff *skb, enum skb_drop_reason reason);
3541 
3542 /**
3543  * __dev_alloc_pages - allocate page for network Rx
3544  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
3545  * @order: size of the allocation
3546  *
3547  * Allocate a new page.
3548  *
3549  * %NULL is returned if there is no free memory.
3550 */
3551 static inline struct page *__dev_alloc_pages_noprof(gfp_t gfp_mask,
3552 					     unsigned int order)
3553 {
3554 	/* This piece of code contains several assumptions.
3555 	 * 1.  This is for device Rx, therefore a cold page is preferred.
3556 	 * 2.  The expectation is the user wants a compound page.
3557 	 * 3.  If requesting a order 0 page it will not be compound
3558 	 *     due to the check to see if order has a value in prep_new_page
3559 	 * 4.  __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
3560 	 *     code in gfp_to_alloc_flags that should be enforcing this.
3561 	 */
3562 	gfp_mask |= __GFP_COMP | __GFP_MEMALLOC;
3563 
3564 	return alloc_pages_node_noprof(NUMA_NO_NODE, gfp_mask, order);
3565 }
3566 #define __dev_alloc_pages(...)	alloc_hooks(__dev_alloc_pages_noprof(__VA_ARGS__))
3567 
3568 /*
3569  * This specialized allocator has to be a macro for its allocations to be
3570  * accounted separately (to have a separate alloc_tag).
3571  */
3572 #define dev_alloc_pages(_order) __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, _order)
3573 
3574 /**
3575  * __dev_alloc_page - allocate a page for network Rx
3576  * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
3577  *
3578  * Allocate a new page.
3579  *
3580  * %NULL is returned if there is no free memory.
3581  */
3582 static inline struct page *__dev_alloc_page_noprof(gfp_t gfp_mask)
3583 {
3584 	return __dev_alloc_pages_noprof(gfp_mask, 0);
3585 }
3586 #define __dev_alloc_page(...)	alloc_hooks(__dev_alloc_page_noprof(__VA_ARGS__))
3587 
3588 /*
3589  * This specialized allocator has to be a macro for its allocations to be
3590  * accounted separately (to have a separate alloc_tag).
3591  */
3592 #define dev_alloc_page()	dev_alloc_pages(0)
3593 
3594 /**
3595  * dev_page_is_reusable - check whether a page can be reused for network Rx
3596  * @page: the page to test
3597  *
3598  * A page shouldn't be considered for reusing/recycling if it was allocated
3599  * under memory pressure or at a distant memory node.
3600  *
3601  * Returns: false if this page should be returned to page allocator, true
3602  * otherwise.
3603  */
3604 static inline bool dev_page_is_reusable(const struct page *page)
3605 {
3606 	return likely(page_to_nid(page) == numa_mem_id() &&
3607 		      !page_is_pfmemalloc(page));
3608 }
3609 
3610 /**
3611  *	skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
3612  *	@page: The page that was allocated from skb_alloc_page
3613  *	@skb: The skb that may need pfmemalloc set
3614  */
3615 static inline void skb_propagate_pfmemalloc(const struct page *page,
3616 					    struct sk_buff *skb)
3617 {
3618 	if (page_is_pfmemalloc(page))
3619 		skb->pfmemalloc = true;
3620 }
3621 
3622 /**
3623  * skb_frag_off() - Returns the offset of a skb fragment
3624  * @frag: the paged fragment
3625  */
3626 static inline unsigned int skb_frag_off(const skb_frag_t *frag)
3627 {
3628 	return frag->offset;
3629 }
3630 
3631 /**
3632  * skb_frag_off_add() - Increments the offset of a skb fragment by @delta
3633  * @frag: skb fragment
3634  * @delta: value to add
3635  */
3636 static inline void skb_frag_off_add(skb_frag_t *frag, int delta)
3637 {
3638 	frag->offset += delta;
3639 }
3640 
3641 /**
3642  * skb_frag_off_set() - Sets the offset of a skb fragment
3643  * @frag: skb fragment
3644  * @offset: offset of fragment
3645  */
3646 static inline void skb_frag_off_set(skb_frag_t *frag, unsigned int offset)
3647 {
3648 	frag->offset = offset;
3649 }
3650 
3651 /**
3652  * skb_frag_off_copy() - Sets the offset of a skb fragment from another fragment
3653  * @fragto: skb fragment where offset is set
3654  * @fragfrom: skb fragment offset is copied from
3655  */
3656 static inline void skb_frag_off_copy(skb_frag_t *fragto,
3657 				     const skb_frag_t *fragfrom)
3658 {
3659 	fragto->offset = fragfrom->offset;
3660 }
3661 
3662 /* Return: true if the skb_frag contains a net_iov. */
3663 static inline bool skb_frag_is_net_iov(const skb_frag_t *frag)
3664 {
3665 	return netmem_is_net_iov(frag->netmem);
3666 }
3667 
3668 /**
3669  * skb_frag_net_iov - retrieve the net_iov referred to by fragment
3670  * @frag: the fragment
3671  *
3672  * Return: the &struct net_iov associated with @frag. Returns NULL if this
3673  * frag has no associated net_iov.
3674  */
3675 static inline struct net_iov *skb_frag_net_iov(const skb_frag_t *frag)
3676 {
3677 	if (!skb_frag_is_net_iov(frag))
3678 		return NULL;
3679 
3680 	return netmem_to_net_iov(frag->netmem);
3681 }
3682 
3683 /**
3684  * skb_frag_page - retrieve the page referred to by a paged fragment
3685  * @frag: the paged fragment
3686  *
3687  * Return: the &struct page associated with @frag. Returns NULL if this frag
3688  * has no associated page.
3689  */
3690 static inline struct page *skb_frag_page(const skb_frag_t *frag)
3691 {
3692 	if (skb_frag_is_net_iov(frag))
3693 		return NULL;
3694 
3695 	return netmem_to_page(frag->netmem);
3696 }
3697 
3698 /**
3699  * skb_frag_netmem - retrieve the netmem referred to by a fragment
3700  * @frag: the fragment
3701  *
3702  * Return: the &netmem_ref associated with @frag.
3703  */
3704 static inline netmem_ref skb_frag_netmem(const skb_frag_t *frag)
3705 {
3706 	return frag->netmem;
3707 }
3708 
3709 int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
3710 		    unsigned int headroom);
3711 int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
3712 			 const struct bpf_prog *prog);
3713 
3714 /**
3715  * skb_frag_address - gets the address of the data contained in a paged fragment
3716  * @frag: the paged fragment buffer
3717  *
3718  * Returns: the address of the data within @frag. The page must already
3719  * be mapped.
3720  */
3721 static inline void *skb_frag_address(const skb_frag_t *frag)
3722 {
3723 	if (!skb_frag_page(frag))
3724 		return NULL;
3725 
3726 	return page_address(skb_frag_page(frag)) + skb_frag_off(frag);
3727 }
3728 
3729 /**
3730  * skb_frag_address_safe - gets the address of the data contained in a paged fragment
3731  * @frag: the paged fragment buffer
3732  *
3733  * Returns: the address of the data within @frag. Checks that the page
3734  * is mapped and returns %NULL otherwise.
3735  */
3736 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
3737 {
3738 	struct page *page = skb_frag_page(frag);
3739 	void *ptr;
3740 
3741 	if (!page)
3742 		return NULL;
3743 
3744 	ptr = page_address(page);
3745 	if (unlikely(!ptr))
3746 		return NULL;
3747 
3748 	return ptr + skb_frag_off(frag);
3749 }
3750 
3751 /**
3752  * skb_frag_page_copy() - sets the page in a fragment from another fragment
3753  * @fragto: skb fragment where page is set
3754  * @fragfrom: skb fragment page is copied from
3755  */
3756 static inline void skb_frag_page_copy(skb_frag_t *fragto,
3757 				      const skb_frag_t *fragfrom)
3758 {
3759 	fragto->netmem = fragfrom->netmem;
3760 }
3761 
3762 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
3763 
3764 /**
3765  * __skb_frag_dma_map - maps a paged fragment via the DMA API
3766  * @dev: the device to map the fragment to
3767  * @frag: the paged fragment to map
3768  * @offset: the offset within the fragment (starting at the
3769  *          fragment's own offset)
3770  * @size: the number of bytes to map
3771  * @dir: the direction of the mapping (``PCI_DMA_*``)
3772  *
3773  * Maps the page associated with @frag to @device.
3774  */
3775 static inline dma_addr_t __skb_frag_dma_map(struct device *dev,
3776 					    const skb_frag_t *frag,
3777 					    size_t offset, size_t size,
3778 					    enum dma_data_direction dir)
3779 {
3780 	if (skb_frag_is_net_iov(frag)) {
3781 		return netmem_to_net_iov(frag->netmem)->dma_addr + offset +
3782 		       frag->offset;
3783 	}
3784 	return dma_map_page(dev, skb_frag_page(frag),
3785 			    skb_frag_off(frag) + offset, size, dir);
3786 }
3787 
3788 #define skb_frag_dma_map(dev, frag, ...)				\
3789 	CONCATENATE(_skb_frag_dma_map,					\
3790 		    COUNT_ARGS(__VA_ARGS__))(dev, frag, ##__VA_ARGS__)
3791 
3792 #define __skb_frag_dma_map1(dev, frag, offset, uf, uo) ({		\
3793 	const skb_frag_t *uf = (frag);					\
3794 	size_t uo = (offset);						\
3795 									\
3796 	__skb_frag_dma_map(dev, uf, uo, skb_frag_size(uf) - uo,		\
3797 			   DMA_TO_DEVICE);				\
3798 })
3799 #define _skb_frag_dma_map1(dev, frag, offset)				\
3800 	__skb_frag_dma_map1(dev, frag, offset, __UNIQUE_ID(frag_),	\
3801 			    __UNIQUE_ID(offset_))
3802 #define _skb_frag_dma_map0(dev, frag)					\
3803 	_skb_frag_dma_map1(dev, frag, 0)
3804 #define _skb_frag_dma_map2(dev, frag, offset, size)			\
3805 	__skb_frag_dma_map(dev, frag, offset, size, DMA_TO_DEVICE)
3806 #define _skb_frag_dma_map3(dev, frag, offset, size, dir)		\
3807 	__skb_frag_dma_map(dev, frag, offset, size, dir)
3808 
3809 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
3810 					gfp_t gfp_mask)
3811 {
3812 	return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
3813 }
3814 
3815 
3816 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
3817 						  gfp_t gfp_mask)
3818 {
3819 	return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
3820 }
3821 
3822 
3823 /**
3824  *	skb_clone_writable - is the header of a clone writable
3825  *	@skb: buffer to check
3826  *	@len: length up to which to write
3827  *
3828  *	Returns true if modifying the header part of the cloned buffer
3829  *	does not requires the data to be copied.
3830  */
3831 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
3832 {
3833 	return !skb_header_cloned(skb) &&
3834 	       skb_headroom(skb) + len <= skb->hdr_len;
3835 }
3836 
3837 static inline int skb_try_make_writable(struct sk_buff *skb,
3838 					unsigned int write_len)
3839 {
3840 	return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
3841 	       pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
3842 }
3843 
3844 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
3845 			    int cloned)
3846 {
3847 	int delta = 0;
3848 
3849 	if (headroom > skb_headroom(skb))
3850 		delta = headroom - skb_headroom(skb);
3851 
3852 	if (delta || cloned)
3853 		return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
3854 					GFP_ATOMIC);
3855 	return 0;
3856 }
3857 
3858 /**
3859  *	skb_cow - copy header of skb when it is required
3860  *	@skb: buffer to cow
3861  *	@headroom: needed headroom
3862  *
3863  *	If the skb passed lacks sufficient headroom or its data part
3864  *	is shared, data is reallocated. If reallocation fails, an error
3865  *	is returned and original skb is not changed.
3866  *
3867  *	The result is skb with writable area skb->head...skb->tail
3868  *	and at least @headroom of space at head.
3869  */
3870 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
3871 {
3872 	return __skb_cow(skb, headroom, skb_cloned(skb));
3873 }
3874 
3875 /**
3876  *	skb_cow_head - skb_cow but only making the head writable
3877  *	@skb: buffer to cow
3878  *	@headroom: needed headroom
3879  *
3880  *	This function is identical to skb_cow except that we replace the
3881  *	skb_cloned check by skb_header_cloned.  It should be used when
3882  *	you only need to push on some header and do not need to modify
3883  *	the data.
3884  */
3885 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
3886 {
3887 	return __skb_cow(skb, headroom, skb_header_cloned(skb));
3888 }
3889 
3890 /**
3891  *	skb_padto	- pad an skbuff up to a minimal size
3892  *	@skb: buffer to pad
3893  *	@len: minimal length
3894  *
3895  *	Pads up a buffer to ensure the trailing bytes exist and are
3896  *	blanked. If the buffer already contains sufficient data it
3897  *	is untouched. Otherwise it is extended. Returns zero on
3898  *	success. The skb is freed on error.
3899  */
3900 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
3901 {
3902 	unsigned int size = skb->len;
3903 	if (likely(size >= len))
3904 		return 0;
3905 	return skb_pad(skb, len - size);
3906 }
3907 
3908 /**
3909  *	__skb_put_padto - increase size and pad an skbuff up to a minimal size
3910  *	@skb: buffer to pad
3911  *	@len: minimal length
3912  *	@free_on_error: free buffer on error
3913  *
3914  *	Pads up a buffer to ensure the trailing bytes exist and are
3915  *	blanked. If the buffer already contains sufficient data it
3916  *	is untouched. Otherwise it is extended. Returns zero on
3917  *	success. The skb is freed on error if @free_on_error is true.
3918  */
3919 static inline int __must_check __skb_put_padto(struct sk_buff *skb,
3920 					       unsigned int len,
3921 					       bool free_on_error)
3922 {
3923 	unsigned int size = skb->len;
3924 
3925 	if (unlikely(size < len)) {
3926 		len -= size;
3927 		if (__skb_pad(skb, len, free_on_error))
3928 			return -ENOMEM;
3929 		__skb_put(skb, len);
3930 	}
3931 	return 0;
3932 }
3933 
3934 /**
3935  *	skb_put_padto - increase size and pad an skbuff up to a minimal size
3936  *	@skb: buffer to pad
3937  *	@len: minimal length
3938  *
3939  *	Pads up a buffer to ensure the trailing bytes exist and are
3940  *	blanked. If the buffer already contains sufficient data it
3941  *	is untouched. Otherwise it is extended. Returns zero on
3942  *	success. The skb is freed on error.
3943  */
3944 static inline int __must_check skb_put_padto(struct sk_buff *skb, unsigned int len)
3945 {
3946 	return __skb_put_padto(skb, len, true);
3947 }
3948 
3949 bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i)
3950 	__must_check;
3951 
3952 static inline bool skb_can_coalesce_netmem(struct sk_buff *skb, int i,
3953 					   netmem_ref netmem, int off)
3954 {
3955 	if (skb_zcopy(skb))
3956 		return false;
3957 	if (i) {
3958 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];
3959 
3960 		return netmem == skb_frag_netmem(frag) &&
3961 		       off == skb_frag_off(frag) + skb_frag_size(frag);
3962 	}
3963 	return false;
3964 }
3965 
3966 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
3967 				    const struct page *page, int off)
3968 {
3969 	return skb_can_coalesce_netmem(skb, i, page_to_netmem(page), off);
3970 }
3971 
3972 static inline int __skb_linearize(struct sk_buff *skb)
3973 {
3974 	return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
3975 }
3976 
3977 /**
3978  *	skb_linearize - convert paged skb to linear one
3979  *	@skb: buffer to linarize
3980  *
3981  *	If there is no free memory -ENOMEM is returned, otherwise zero
3982  *	is returned and the old skb data released.
3983  */
3984 static inline int skb_linearize(struct sk_buff *skb)
3985 {
3986 	return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
3987 }
3988 
3989 /**
3990  * skb_has_shared_frag - can any frag be overwritten
3991  * @skb: buffer to test
3992  *
3993  * Return: true if the skb has at least one frag that might be modified
3994  * by an external entity (as in vmsplice()/sendfile())
3995  */
3996 static inline bool skb_has_shared_frag(const struct sk_buff *skb)
3997 {
3998 	return skb_is_nonlinear(skb) &&
3999 	       skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
4000 }
4001 
4002 /**
4003  *	skb_linearize_cow - make sure skb is linear and writable
4004  *	@skb: buffer to process
4005  *
4006  *	If there is no free memory -ENOMEM is returned, otherwise zero
4007  *	is returned and the old skb data released.
4008  */
4009 static inline int skb_linearize_cow(struct sk_buff *skb)
4010 {
4011 	return skb_is_nonlinear(skb) || skb_cloned(skb) ?
4012 	       __skb_linearize(skb) : 0;
4013 }
4014 
4015 static __always_inline void
4016 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
4017 		     unsigned int off)
4018 {
4019 	if (skb->ip_summed == CHECKSUM_COMPLETE)
4020 		skb->csum = csum_block_sub(skb->csum,
4021 					   csum_partial(start, len, 0), off);
4022 	else if (skb->ip_summed == CHECKSUM_PARTIAL &&
4023 		 skb_checksum_start_offset(skb) < 0)
4024 		skb->ip_summed = CHECKSUM_NONE;
4025 }
4026 
4027 /**
4028  *	skb_postpull_rcsum - update checksum for received skb after pull
4029  *	@skb: buffer to update
4030  *	@start: start of data before pull
4031  *	@len: length of data pulled
4032  *
4033  *	After doing a pull on a received packet, you need to call this to
4034  *	update the CHECKSUM_COMPLETE checksum, or set ip_summed to
4035  *	CHECKSUM_NONE so that it can be recomputed from scratch.
4036  */
4037 static inline void skb_postpull_rcsum(struct sk_buff *skb,
4038 				      const void *start, unsigned int len)
4039 {
4040 	if (skb->ip_summed == CHECKSUM_COMPLETE)
4041 		skb->csum = wsum_negate(csum_partial(start, len,
4042 						     wsum_negate(skb->csum)));
4043 	else if (skb->ip_summed == CHECKSUM_PARTIAL &&
4044 		 skb_checksum_start_offset(skb) < 0)
4045 		skb->ip_summed = CHECKSUM_NONE;
4046 }
4047 
4048 static __always_inline void
4049 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
4050 		     unsigned int off)
4051 {
4052 	if (skb->ip_summed == CHECKSUM_COMPLETE)
4053 		skb->csum = csum_block_add(skb->csum,
4054 					   csum_partial(start, len, 0), off);
4055 }
4056 
4057 /**
4058  *	skb_postpush_rcsum - update checksum for received skb after push
4059  *	@skb: buffer to update
4060  *	@start: start of data after push
4061  *	@len: length of data pushed
4062  *
4063  *	After doing a push on a received packet, you need to call this to
4064  *	update the CHECKSUM_COMPLETE checksum.
4065  */
4066 static inline void skb_postpush_rcsum(struct sk_buff *skb,
4067 				      const void *start, unsigned int len)
4068 {
4069 	__skb_postpush_rcsum(skb, start, len, 0);
4070 }
4071 
4072 void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
4073 
4074 /**
4075  *	skb_push_rcsum - push skb and update receive checksum
4076  *	@skb: buffer to update
4077  *	@len: length of data pulled
4078  *
4079  *	This function performs an skb_push on the packet and updates
4080  *	the CHECKSUM_COMPLETE checksum.  It should be used on
4081  *	receive path processing instead of skb_push unless you know
4082  *	that the checksum difference is zero (e.g., a valid IP header)
4083  *	or you are setting ip_summed to CHECKSUM_NONE.
4084  */
4085 static inline void *skb_push_rcsum(struct sk_buff *skb, unsigned int len)
4086 {
4087 	skb_push(skb, len);
4088 	skb_postpush_rcsum(skb, skb->data, len);
4089 	return skb->data;
4090 }
4091 
4092 int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len);
4093 /**
4094  *	pskb_trim_rcsum - trim received skb and update checksum
4095  *	@skb: buffer to trim
4096  *	@len: new length
4097  *
4098  *	This is exactly the same as pskb_trim except that it ensures the
4099  *	checksum of received packets are still valid after the operation.
4100  *	It can change skb pointers.
4101  */
4102 
4103 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
4104 {
4105 	skb_might_realloc(skb);
4106 	if (likely(len >= skb->len))
4107 		return 0;
4108 	return pskb_trim_rcsum_slow(skb, len);
4109 }
4110 
4111 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
4112 {
4113 	if (skb->ip_summed == CHECKSUM_COMPLETE)
4114 		skb->ip_summed = CHECKSUM_NONE;
4115 	__skb_trim(skb, len);
4116 	return 0;
4117 }
4118 
4119 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
4120 {
4121 	if (skb->ip_summed == CHECKSUM_COMPLETE)
4122 		skb->ip_summed = CHECKSUM_NONE;
4123 	return __skb_grow(skb, len);
4124 }
4125 
4126 #define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode)
4127 #define skb_rb_first(root) rb_to_skb(rb_first(root))
4128 #define skb_rb_last(root)  rb_to_skb(rb_last(root))
4129 #define skb_rb_next(skb)   rb_to_skb(rb_next(&(skb)->rbnode))
4130 #define skb_rb_prev(skb)   rb_to_skb(rb_prev(&(skb)->rbnode))
4131 
4132 #define skb_queue_walk(queue, skb) \
4133 		for (skb = (queue)->next;					\
4134 		     skb != (struct sk_buff *)(queue);				\
4135 		     skb = skb->next)
4136 
4137 #define skb_queue_walk_safe(queue, skb, tmp)					\
4138 		for (skb = (queue)->next, tmp = skb->next;			\
4139 		     skb != (struct sk_buff *)(queue);				\
4140 		     skb = tmp, tmp = skb->next)
4141 
4142 #define skb_queue_walk_from(queue, skb)						\
4143 		for (; skb != (struct sk_buff *)(queue);			\
4144 		     skb = skb->next)
4145 
4146 #define skb_rbtree_walk(skb, root)						\
4147 		for (skb = skb_rb_first(root); skb != NULL;			\
4148 		     skb = skb_rb_next(skb))
4149 
4150 #define skb_rbtree_walk_from(skb)						\
4151 		for (; skb != NULL;						\
4152 		     skb = skb_rb_next(skb))
4153 
4154 #define skb_rbtree_walk_from_safe(skb, tmp)					\
4155 		for (; tmp = skb ? skb_rb_next(skb) : NULL, (skb != NULL);	\
4156 		     skb = tmp)
4157 
4158 #define skb_queue_walk_from_safe(queue, skb, tmp)				\
4159 		for (tmp = skb->next;						\
4160 		     skb != (struct sk_buff *)(queue);				\
4161 		     skb = tmp, tmp = skb->next)
4162 
4163 #define skb_queue_reverse_walk(queue, skb) \
4164 		for (skb = (queue)->prev;					\
4165 		     skb != (struct sk_buff *)(queue);				\
4166 		     skb = skb->prev)
4167 
4168 #define skb_queue_reverse_walk_safe(queue, skb, tmp)				\
4169 		for (skb = (queue)->prev, tmp = skb->prev;			\
4170 		     skb != (struct sk_buff *)(queue);				\
4171 		     skb = tmp, tmp = skb->prev)
4172 
4173 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp)			\
4174 		for (tmp = skb->prev;						\
4175 		     skb != (struct sk_buff *)(queue);				\
4176 		     skb = tmp, tmp = skb->prev)
4177 
4178 static inline bool skb_has_frag_list(const struct sk_buff *skb)
4179 {
4180 	return skb_shinfo(skb)->frag_list != NULL;
4181 }
4182 
4183 static inline void skb_frag_list_init(struct sk_buff *skb)
4184 {
4185 	skb_shinfo(skb)->frag_list = NULL;
4186 }
4187 
4188 #define skb_walk_frags(skb, iter)	\
4189 	for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
4190 
4191 
4192 int __skb_wait_for_more_packets(struct sock *sk, struct sk_buff_head *queue,
4193 				int *err, long *timeo_p,
4194 				const struct sk_buff *skb);
4195 struct sk_buff *__skb_try_recv_from_queue(struct sk_buff_head *queue,
4196 					  unsigned int flags,
4197 					  int *off, int *err,
4198 					  struct sk_buff **last);
4199 struct sk_buff *__skb_try_recv_datagram(struct sock *sk,
4200 					struct sk_buff_head *queue,
4201 					unsigned int flags, int *off, int *err,
4202 					struct sk_buff **last);
4203 struct sk_buff *__skb_recv_datagram(struct sock *sk,
4204 				    struct sk_buff_head *sk_queue,
4205 				    unsigned int flags, int *off, int *err);
4206 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags, int *err);
4207 __poll_t datagram_poll(struct file *file, struct socket *sock,
4208 			   struct poll_table_struct *wait);
4209 int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
4210 			   struct iov_iter *to, int size);
4211 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
4212 					struct msghdr *msg, int size)
4213 {
4214 	return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
4215 }
4216 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
4217 				   struct msghdr *msg);
4218 int skb_copy_and_crc32c_datagram_iter(const struct sk_buff *skb, int offset,
4219 				      struct iov_iter *to, int len, u32 *crcp);
4220 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
4221 				 struct iov_iter *from, int len);
4222 int skb_copy_datagram_from_iter_full(struct sk_buff *skb, int offset,
4223 				     struct iov_iter *from, int len);
4224 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
4225 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
4226 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
4227 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
4228 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
4229 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
4230 			      int len);
4231 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
4232 		    struct pipe_inode_info *pipe, unsigned int len,
4233 		    unsigned int flags);
4234 int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
4235 			 int len);
4236 int skb_send_sock_locked_with_flags(struct sock *sk, struct sk_buff *skb,
4237 				    int offset, int len, int flags);
4238 int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len);
4239 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
4240 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
4241 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
4242 		 int len, int hlen);
4243 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
4244 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
4245 void skb_scrub_packet(struct sk_buff *skb, bool xnet);
4246 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
4247 struct sk_buff *skb_segment_list(struct sk_buff *skb, netdev_features_t features,
4248 				 unsigned int offset);
4249 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
4250 int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len);
4251 int skb_ensure_writable_head_tail(struct sk_buff *skb, struct net_device *dev);
4252 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
4253 int skb_vlan_pop(struct sk_buff *skb);
4254 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
4255 int skb_eth_pop(struct sk_buff *skb);
4256 int skb_eth_push(struct sk_buff *skb, const unsigned char *dst,
4257 		 const unsigned char *src);
4258 int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
4259 		  int mac_len, bool ethernet);
4260 int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
4261 		 bool ethernet);
4262 int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse);
4263 int skb_mpls_dec_ttl(struct sk_buff *skb);
4264 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
4265 			     gfp_t gfp);
4266 
4267 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
4268 {
4269 	return copy_from_iter_full(data, len, &msg->msg_iter) ? 0 : -EFAULT;
4270 }
4271 
4272 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
4273 {
4274 	return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
4275 }
4276 
4277 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
4278 		    __wsum csum);
4279 u32 skb_crc32c(const struct sk_buff *skb, int offset, int len, u32 crc);
4280 
4281 static inline void * __must_check
4282 __skb_header_pointer(const struct sk_buff *skb, int offset, int len,
4283 		     const void *data, int hlen, void *buffer)
4284 {
4285 	if (likely(hlen - offset >= len))
4286 		return (void *)data + offset;
4287 
4288 	if (!skb || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0))
4289 		return NULL;
4290 
4291 	return buffer;
4292 }
4293 
4294 static inline void * __must_check
4295 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
4296 {
4297 	return __skb_header_pointer(skb, offset, len, skb->data,
4298 				    skb_headlen(skb), buffer);
4299 }
4300 
4301 static inline void * __must_check
4302 skb_pointer_if_linear(const struct sk_buff *skb, int offset, int len)
4303 {
4304 	if (likely(skb_headlen(skb) - offset >= len))
4305 		return skb->data + offset;
4306 	return NULL;
4307 }
4308 
4309 /**
4310  *	skb_needs_linearize - check if we need to linearize a given skb
4311  *			      depending on the given device features.
4312  *	@skb: socket buffer to check
4313  *	@features: net device features
4314  *
4315  *	Returns true if either:
4316  *	1. skb has frag_list and the device doesn't support FRAGLIST, or
4317  *	2. skb is fragmented and the device does not support SG.
4318  */
4319 static inline bool skb_needs_linearize(struct sk_buff *skb,
4320 				       netdev_features_t features)
4321 {
4322 	return skb_is_nonlinear(skb) &&
4323 	       ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
4324 		(skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
4325 }
4326 
4327 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
4328 					     void *to,
4329 					     const unsigned int len)
4330 {
4331 	memcpy(to, skb->data, len);
4332 }
4333 
4334 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
4335 						    const int offset, void *to,
4336 						    const unsigned int len)
4337 {
4338 	memcpy(to, skb->data + offset, len);
4339 }
4340 
4341 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
4342 					   const void *from,
4343 					   const unsigned int len)
4344 {
4345 	memcpy(skb->data, from, len);
4346 }
4347 
4348 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
4349 						  const int offset,
4350 						  const void *from,
4351 						  const unsigned int len)
4352 {
4353 	memcpy(skb->data + offset, from, len);
4354 }
4355 
4356 void skb_init(void);
4357 
4358 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
4359 {
4360 	return skb->tstamp;
4361 }
4362 
4363 /**
4364  *	skb_get_timestamp - get timestamp from a skb
4365  *	@skb: skb to get stamp from
4366  *	@stamp: pointer to struct __kernel_old_timeval to store stamp in
4367  *
4368  *	Timestamps are stored in the skb as offsets to a base timestamp.
4369  *	This function converts the offset back to a struct timeval and stores
4370  *	it in stamp.
4371  */
4372 static inline void skb_get_timestamp(const struct sk_buff *skb,
4373 				     struct __kernel_old_timeval *stamp)
4374 {
4375 	*stamp = ns_to_kernel_old_timeval(skb->tstamp);
4376 }
4377 
4378 static inline void skb_get_new_timestamp(const struct sk_buff *skb,
4379 					 struct __kernel_sock_timeval *stamp)
4380 {
4381 	struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
4382 
4383 	stamp->tv_sec = ts.tv_sec;
4384 	stamp->tv_usec = ts.tv_nsec / 1000;
4385 }
4386 
4387 static inline void skb_get_timestampns(const struct sk_buff *skb,
4388 				       struct __kernel_old_timespec *stamp)
4389 {
4390 	struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
4391 
4392 	stamp->tv_sec = ts.tv_sec;
4393 	stamp->tv_nsec = ts.tv_nsec;
4394 }
4395 
4396 static inline void skb_get_new_timestampns(const struct sk_buff *skb,
4397 					   struct __kernel_timespec *stamp)
4398 {
4399 	struct timespec64 ts = ktime_to_timespec64(skb->tstamp);
4400 
4401 	stamp->tv_sec = ts.tv_sec;
4402 	stamp->tv_nsec = ts.tv_nsec;
4403 }
4404 
4405 static inline void __net_timestamp(struct sk_buff *skb)
4406 {
4407 	skb->tstamp = ktime_get_real();
4408 	skb->tstamp_type = SKB_CLOCK_REALTIME;
4409 }
4410 
4411 static inline ktime_t net_timedelta(ktime_t t)
4412 {
4413 	return ktime_sub(ktime_get_real(), t);
4414 }
4415 
4416 static inline void skb_set_delivery_time(struct sk_buff *skb, ktime_t kt,
4417 					 u8 tstamp_type)
4418 {
4419 	skb->tstamp = kt;
4420 
4421 	if (kt)
4422 		skb->tstamp_type = tstamp_type;
4423 	else
4424 		skb->tstamp_type = SKB_CLOCK_REALTIME;
4425 }
4426 
4427 static inline void skb_set_delivery_type_by_clockid(struct sk_buff *skb,
4428 						    ktime_t kt, clockid_t clockid)
4429 {
4430 	u8 tstamp_type = SKB_CLOCK_REALTIME;
4431 
4432 	switch (clockid) {
4433 	case CLOCK_REALTIME:
4434 		break;
4435 	case CLOCK_MONOTONIC:
4436 		tstamp_type = SKB_CLOCK_MONOTONIC;
4437 		break;
4438 	case CLOCK_TAI:
4439 		tstamp_type = SKB_CLOCK_TAI;
4440 		break;
4441 	default:
4442 		WARN_ON_ONCE(1);
4443 		kt = 0;
4444 	}
4445 
4446 	skb_set_delivery_time(skb, kt, tstamp_type);
4447 }
4448 
4449 DECLARE_STATIC_KEY_FALSE(netstamp_needed_key);
4450 
4451 /* It is used in the ingress path to clear the delivery_time.
4452  * If needed, set the skb->tstamp to the (rcv) timestamp.
4453  */
4454 static inline void skb_clear_delivery_time(struct sk_buff *skb)
4455 {
4456 	if (skb->tstamp_type) {
4457 		skb->tstamp_type = SKB_CLOCK_REALTIME;
4458 		if (static_branch_unlikely(&netstamp_needed_key))
4459 			skb->tstamp = ktime_get_real();
4460 		else
4461 			skb->tstamp = 0;
4462 	}
4463 }
4464 
4465 static inline void skb_clear_tstamp(struct sk_buff *skb)
4466 {
4467 	if (skb->tstamp_type)
4468 		return;
4469 
4470 	skb->tstamp = 0;
4471 }
4472 
4473 static inline ktime_t skb_tstamp(const struct sk_buff *skb)
4474 {
4475 	if (skb->tstamp_type)
4476 		return 0;
4477 
4478 	return skb->tstamp;
4479 }
4480 
4481 static inline ktime_t skb_tstamp_cond(const struct sk_buff *skb, bool cond)
4482 {
4483 	if (skb->tstamp_type != SKB_CLOCK_MONOTONIC && skb->tstamp)
4484 		return skb->tstamp;
4485 
4486 	if (static_branch_unlikely(&netstamp_needed_key) || cond)
4487 		return ktime_get_real();
4488 
4489 	return 0;
4490 }
4491 
4492 static inline u8 skb_metadata_len(const struct sk_buff *skb)
4493 {
4494 	return skb_shinfo(skb)->meta_len;
4495 }
4496 
4497 static inline void *skb_metadata_end(const struct sk_buff *skb)
4498 {
4499 	return skb_mac_header(skb);
4500 }
4501 
4502 static inline bool __skb_metadata_differs(const struct sk_buff *skb_a,
4503 					  const struct sk_buff *skb_b,
4504 					  u8 meta_len)
4505 {
4506 	const void *a = skb_metadata_end(skb_a);
4507 	const void *b = skb_metadata_end(skb_b);
4508 	u64 diffs = 0;
4509 
4510 	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ||
4511 	    BITS_PER_LONG != 64)
4512 		goto slow;
4513 
4514 	/* Using more efficient variant than plain call to memcmp(). */
4515 	switch (meta_len) {
4516 #define __it(x, op) (x -= sizeof(u##op))
4517 #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op))
4518 	case 32: diffs |= __it_diff(a, b, 64);
4519 		fallthrough;
4520 	case 24: diffs |= __it_diff(a, b, 64);
4521 		fallthrough;
4522 	case 16: diffs |= __it_diff(a, b, 64);
4523 		fallthrough;
4524 	case  8: diffs |= __it_diff(a, b, 64);
4525 		break;
4526 	case 28: diffs |= __it_diff(a, b, 64);
4527 		fallthrough;
4528 	case 20: diffs |= __it_diff(a, b, 64);
4529 		fallthrough;
4530 	case 12: diffs |= __it_diff(a, b, 64);
4531 		fallthrough;
4532 	case  4: diffs |= __it_diff(a, b, 32);
4533 		break;
4534 	default:
4535 slow:
4536 		return memcmp(a - meta_len, b - meta_len, meta_len);
4537 	}
4538 	return diffs;
4539 }
4540 
4541 static inline bool skb_metadata_differs(const struct sk_buff *skb_a,
4542 					const struct sk_buff *skb_b)
4543 {
4544 	u8 len_a = skb_metadata_len(skb_a);
4545 	u8 len_b = skb_metadata_len(skb_b);
4546 
4547 	if (!(len_a | len_b))
4548 		return false;
4549 
4550 	return len_a != len_b ?
4551 	       true : __skb_metadata_differs(skb_a, skb_b, len_a);
4552 }
4553 
4554 static inline void skb_metadata_set(struct sk_buff *skb, u8 meta_len)
4555 {
4556 	skb_shinfo(skb)->meta_len = meta_len;
4557 }
4558 
4559 static inline void skb_metadata_clear(struct sk_buff *skb)
4560 {
4561 	skb_metadata_set(skb, 0);
4562 }
4563 
4564 struct sk_buff *skb_clone_sk(struct sk_buff *skb);
4565 
4566 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
4567 
4568 void skb_clone_tx_timestamp(struct sk_buff *skb);
4569 bool skb_defer_rx_timestamp(struct sk_buff *skb);
4570 
4571 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
4572 
4573 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
4574 {
4575 }
4576 
4577 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
4578 {
4579 	return false;
4580 }
4581 
4582 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
4583 
4584 /**
4585  * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
4586  *
4587  * PHY drivers may accept clones of transmitted packets for
4588  * timestamping via their phy_driver.txtstamp method. These drivers
4589  * must call this function to return the skb back to the stack with a
4590  * timestamp.
4591  *
4592  * @skb: clone of the original outgoing packet
4593  * @hwtstamps: hardware time stamps
4594  *
4595  */
4596 void skb_complete_tx_timestamp(struct sk_buff *skb,
4597 			       struct skb_shared_hwtstamps *hwtstamps);
4598 
4599 void __skb_tstamp_tx(struct sk_buff *orig_skb, const struct sk_buff *ack_skb,
4600 		     struct skb_shared_hwtstamps *hwtstamps,
4601 		     struct sock *sk, int tstype);
4602 
4603 /**
4604  * skb_tstamp_tx - queue clone of skb with send time stamps
4605  * @orig_skb:	the original outgoing packet
4606  * @hwtstamps:	hardware time stamps, may be NULL if not available
4607  *
4608  * If the skb has a socket associated, then this function clones the
4609  * skb (thus sharing the actual data and optional structures), stores
4610  * the optional hardware time stamping information (if non NULL) or
4611  * generates a software time stamp (otherwise), then queues the clone
4612  * to the error queue of the socket.  Errors are silently ignored.
4613  */
4614 void skb_tstamp_tx(struct sk_buff *orig_skb,
4615 		   struct skb_shared_hwtstamps *hwtstamps);
4616 
4617 /**
4618  * skb_tx_timestamp() - Driver hook for transmit timestamping
4619  *
4620  * Ethernet MAC Drivers should call this function in their hard_xmit()
4621  * function immediately before giving the sk_buff to the MAC hardware.
4622  *
4623  * Specifically, one should make absolutely sure that this function is
4624  * called before TX completion of this packet can trigger.  Otherwise
4625  * the packet could potentially already be freed.
4626  *
4627  * @skb: A socket buffer.
4628  */
4629 static inline void skb_tx_timestamp(struct sk_buff *skb)
4630 {
4631 	skb_clone_tx_timestamp(skb);
4632 	if (skb_shinfo(skb)->tx_flags & (SKBTX_SW_TSTAMP | SKBTX_BPF))
4633 		skb_tstamp_tx(skb, NULL);
4634 }
4635 
4636 /**
4637  * skb_complete_wifi_ack - deliver skb with wifi status
4638  *
4639  * @skb: the original outgoing packet
4640  * @acked: ack status
4641  *
4642  */
4643 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
4644 
4645 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
4646 __sum16 __skb_checksum_complete(struct sk_buff *skb);
4647 
4648 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
4649 {
4650 	return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
4651 		skb->csum_valid ||
4652 		(skb->ip_summed == CHECKSUM_PARTIAL &&
4653 		 skb_checksum_start_offset(skb) >= 0));
4654 }
4655 
4656 /**
4657  *	skb_checksum_complete - Calculate checksum of an entire packet
4658  *	@skb: packet to process
4659  *
4660  *	This function calculates the checksum over the entire packet plus
4661  *	the value of skb->csum.  The latter can be used to supply the
4662  *	checksum of a pseudo header as used by TCP/UDP.  It returns the
4663  *	checksum.
4664  *
4665  *	For protocols that contain complete checksums such as ICMP/TCP/UDP,
4666  *	this function can be used to verify that checksum on received
4667  *	packets.  In that case the function should return zero if the
4668  *	checksum is correct.  In particular, this function will return zero
4669  *	if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
4670  *	hardware has already verified the correctness of the checksum.
4671  */
4672 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
4673 {
4674 	return skb_csum_unnecessary(skb) ?
4675 	       0 : __skb_checksum_complete(skb);
4676 }
4677 
4678 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
4679 {
4680 	if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
4681 		if (skb->csum_level == 0)
4682 			skb->ip_summed = CHECKSUM_NONE;
4683 		else
4684 			skb->csum_level--;
4685 	}
4686 }
4687 
4688 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
4689 {
4690 	if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
4691 		if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
4692 			skb->csum_level++;
4693 	} else if (skb->ip_summed == CHECKSUM_NONE) {
4694 		skb->ip_summed = CHECKSUM_UNNECESSARY;
4695 		skb->csum_level = 0;
4696 	}
4697 }
4698 
4699 static inline void __skb_reset_checksum_unnecessary(struct sk_buff *skb)
4700 {
4701 	if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
4702 		skb->ip_summed = CHECKSUM_NONE;
4703 		skb->csum_level = 0;
4704 	}
4705 }
4706 
4707 /* Check if we need to perform checksum complete validation.
4708  *
4709  * Returns: true if checksum complete is needed, false otherwise
4710  * (either checksum is unnecessary or zero checksum is allowed).
4711  */
4712 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
4713 						  bool zero_okay,
4714 						  __sum16 check)
4715 {
4716 	if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
4717 		skb->csum_valid = 1;
4718 		__skb_decr_checksum_unnecessary(skb);
4719 		return false;
4720 	}
4721 
4722 	return true;
4723 }
4724 
4725 /* For small packets <= CHECKSUM_BREAK perform checksum complete directly
4726  * in checksum_init.
4727  */
4728 #define CHECKSUM_BREAK 76
4729 
4730 /* Unset checksum-complete
4731  *
4732  * Unset checksum complete can be done when packet is being modified
4733  * (uncompressed for instance) and checksum-complete value is
4734  * invalidated.
4735  */
4736 static inline void skb_checksum_complete_unset(struct sk_buff *skb)
4737 {
4738 	if (skb->ip_summed == CHECKSUM_COMPLETE)
4739 		skb->ip_summed = CHECKSUM_NONE;
4740 }
4741 
4742 /* Validate (init) checksum based on checksum complete.
4743  *
4744  * Return values:
4745  *   0: checksum is validated or try to in skb_checksum_complete. In the latter
4746  *	case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
4747  *	checksum is stored in skb->csum for use in __skb_checksum_complete
4748  *   non-zero: value of invalid checksum
4749  *
4750  */
4751 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
4752 						       bool complete,
4753 						       __wsum psum)
4754 {
4755 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
4756 		if (!csum_fold(csum_add(psum, skb->csum))) {
4757 			skb->csum_valid = 1;
4758 			return 0;
4759 		}
4760 	}
4761 
4762 	skb->csum = psum;
4763 
4764 	if (complete || skb->len <= CHECKSUM_BREAK) {
4765 		__sum16 csum;
4766 
4767 		csum = __skb_checksum_complete(skb);
4768 		skb->csum_valid = !csum;
4769 		return csum;
4770 	}
4771 
4772 	return 0;
4773 }
4774 
4775 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
4776 {
4777 	return 0;
4778 }
4779 
4780 /* Perform checksum validate (init). Note that this is a macro since we only
4781  * want to calculate the pseudo header which is an input function if necessary.
4782  * First we try to validate without any computation (checksum unnecessary) and
4783  * then calculate based on checksum complete calling the function to compute
4784  * pseudo header.
4785  *
4786  * Return values:
4787  *   0: checksum is validated or try to in skb_checksum_complete
4788  *   non-zero: value of invalid checksum
4789  */
4790 #define __skb_checksum_validate(skb, proto, complete,			\
4791 				zero_okay, check, compute_pseudo)	\
4792 ({									\
4793 	__sum16 __ret = 0;						\
4794 	skb->csum_valid = 0;						\
4795 	if (__skb_checksum_validate_needed(skb, zero_okay, check))	\
4796 		__ret = __skb_checksum_validate_complete(skb,		\
4797 				complete, compute_pseudo(skb, proto));	\
4798 	__ret;								\
4799 })
4800 
4801 #define skb_checksum_init(skb, proto, compute_pseudo)			\
4802 	__skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
4803 
4804 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo)	\
4805 	__skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
4806 
4807 #define skb_checksum_validate(skb, proto, compute_pseudo)		\
4808 	__skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
4809 
4810 #define skb_checksum_validate_zero_check(skb, proto, check,		\
4811 					 compute_pseudo)		\
4812 	__skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
4813 
4814 #define skb_checksum_simple_validate(skb)				\
4815 	__skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
4816 
4817 static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
4818 {
4819 	return (skb->ip_summed == CHECKSUM_NONE && skb->csum_valid);
4820 }
4821 
4822 static inline void __skb_checksum_convert(struct sk_buff *skb, __wsum pseudo)
4823 {
4824 	skb->csum = ~pseudo;
4825 	skb->ip_summed = CHECKSUM_COMPLETE;
4826 }
4827 
4828 #define skb_checksum_try_convert(skb, proto, compute_pseudo)	\
4829 do {									\
4830 	if (__skb_checksum_convert_check(skb))				\
4831 		__skb_checksum_convert(skb, compute_pseudo(skb, proto)); \
4832 } while (0)
4833 
4834 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
4835 					      u16 start, u16 offset)
4836 {
4837 	skb->ip_summed = CHECKSUM_PARTIAL;
4838 	skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
4839 	skb->csum_offset = offset - start;
4840 }
4841 
4842 /* Update skbuf and packet to reflect the remote checksum offload operation.
4843  * When called, ptr indicates the starting point for skb->csum when
4844  * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
4845  * here, skb_postpull_rcsum is done so skb->csum start is ptr.
4846  */
4847 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
4848 				       int start, int offset, bool nopartial)
4849 {
4850 	__wsum delta;
4851 
4852 	if (!nopartial) {
4853 		skb_remcsum_adjust_partial(skb, ptr, start, offset);
4854 		return;
4855 	}
4856 
4857 	if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
4858 		__skb_checksum_complete(skb);
4859 		skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
4860 	}
4861 
4862 	delta = remcsum_adjust(ptr, skb->csum, start, offset);
4863 
4864 	/* Adjust skb->csum since we changed the packet */
4865 	skb->csum = csum_add(skb->csum, delta);
4866 }
4867 
4868 static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb)
4869 {
4870 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
4871 	return (void *)(skb->_nfct & NFCT_PTRMASK);
4872 #else
4873 	return NULL;
4874 #endif
4875 }
4876 
4877 static inline unsigned long skb_get_nfct(const struct sk_buff *skb)
4878 {
4879 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
4880 	return skb->_nfct;
4881 #else
4882 	return 0UL;
4883 #endif
4884 }
4885 
4886 static inline void skb_set_nfct(struct sk_buff *skb, unsigned long nfct)
4887 {
4888 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
4889 	skb->slow_gro |= !!nfct;
4890 	skb->_nfct = nfct;
4891 #endif
4892 }
4893 
4894 #ifdef CONFIG_SKB_EXTENSIONS
4895 enum skb_ext_id {
4896 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4897 	SKB_EXT_BRIDGE_NF,
4898 #endif
4899 #ifdef CONFIG_XFRM
4900 	SKB_EXT_SEC_PATH,
4901 #endif
4902 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
4903 	TC_SKB_EXT,
4904 #endif
4905 #if IS_ENABLED(CONFIG_MPTCP)
4906 	SKB_EXT_MPTCP,
4907 #endif
4908 #if IS_ENABLED(CONFIG_MCTP_FLOWS)
4909 	SKB_EXT_MCTP,
4910 #endif
4911 #if IS_ENABLED(CONFIG_INET_PSP)
4912 	SKB_EXT_PSP,
4913 #endif
4914 	SKB_EXT_NUM, /* must be last */
4915 };
4916 
4917 /**
4918  *	struct skb_ext - sk_buff extensions
4919  *	@refcnt: 1 on allocation, deallocated on 0
4920  *	@offset: offset to add to @data to obtain extension address
4921  *	@chunks: size currently allocated, stored in SKB_EXT_ALIGN_SHIFT units
4922  *	@data: start of extension data, variable sized
4923  *
4924  *	Note: offsets/lengths are stored in chunks of 8 bytes, this allows
4925  *	to use 'u8' types while allowing up to 2kb worth of extension data.
4926  */
4927 struct skb_ext {
4928 	refcount_t refcnt;
4929 	u8 offset[SKB_EXT_NUM]; /* in chunks of 8 bytes */
4930 	u8 chunks;		/* same */
4931 	char data[] __aligned(8);
4932 };
4933 
4934 struct skb_ext *__skb_ext_alloc(gfp_t flags);
4935 void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id,
4936 		    struct skb_ext *ext);
4937 void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id);
4938 void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id);
4939 void __skb_ext_put(struct skb_ext *ext);
4940 
4941 static inline void skb_ext_put(struct sk_buff *skb)
4942 {
4943 	if (skb->active_extensions)
4944 		__skb_ext_put(skb->extensions);
4945 }
4946 
4947 static inline void __skb_ext_copy(struct sk_buff *dst,
4948 				  const struct sk_buff *src)
4949 {
4950 	dst->active_extensions = src->active_extensions;
4951 
4952 	if (src->active_extensions) {
4953 		struct skb_ext *ext = src->extensions;
4954 
4955 		refcount_inc(&ext->refcnt);
4956 		dst->extensions = ext;
4957 	}
4958 }
4959 
4960 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src)
4961 {
4962 	skb_ext_put(dst);
4963 	__skb_ext_copy(dst, src);
4964 }
4965 
4966 static inline bool __skb_ext_exist(const struct skb_ext *ext, enum skb_ext_id i)
4967 {
4968 	return !!ext->offset[i];
4969 }
4970 
4971 static inline bool skb_ext_exist(const struct sk_buff *skb, enum skb_ext_id id)
4972 {
4973 	return skb->active_extensions & (1 << id);
4974 }
4975 
4976 static inline void skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
4977 {
4978 	if (skb_ext_exist(skb, id))
4979 		__skb_ext_del(skb, id);
4980 }
4981 
4982 static inline void *skb_ext_find(const struct sk_buff *skb, enum skb_ext_id id)
4983 {
4984 	if (skb_ext_exist(skb, id)) {
4985 		struct skb_ext *ext = skb->extensions;
4986 
4987 		return (void *)ext + (ext->offset[id] << 3);
4988 	}
4989 
4990 	return NULL;
4991 }
4992 
4993 static inline void skb_ext_reset(struct sk_buff *skb)
4994 {
4995 	if (unlikely(skb->active_extensions)) {
4996 		__skb_ext_put(skb->extensions);
4997 		skb->active_extensions = 0;
4998 	}
4999 }
5000 
5001 static inline bool skb_has_extensions(struct sk_buff *skb)
5002 {
5003 	return unlikely(skb->active_extensions);
5004 }
5005 #else
5006 static inline void skb_ext_put(struct sk_buff *skb) {}
5007 static inline void skb_ext_reset(struct sk_buff *skb) {}
5008 static inline void skb_ext_del(struct sk_buff *skb, int unused) {}
5009 static inline void __skb_ext_copy(struct sk_buff *d, const struct sk_buff *s) {}
5010 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *s) {}
5011 static inline bool skb_has_extensions(struct sk_buff *skb) { return false; }
5012 #endif /* CONFIG_SKB_EXTENSIONS */
5013 
5014 static inline void nf_reset_ct(struct sk_buff *skb)
5015 {
5016 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
5017 	nf_conntrack_put(skb_nfct(skb));
5018 	skb->_nfct = 0;
5019 #endif
5020 }
5021 
5022 static inline void nf_reset_trace(struct sk_buff *skb)
5023 {
5024 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || IS_ENABLED(CONFIG_NF_TABLES)
5025 	skb->nf_trace = 0;
5026 #endif
5027 }
5028 
5029 static inline void ipvs_reset(struct sk_buff *skb)
5030 {
5031 #if IS_ENABLED(CONFIG_IP_VS)
5032 	skb->ipvs_property = 0;
5033 #endif
5034 }
5035 
5036 /* Note: This doesn't put any conntrack info in dst. */
5037 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
5038 			     bool copy)
5039 {
5040 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
5041 	dst->_nfct = src->_nfct;
5042 	nf_conntrack_get(skb_nfct(src));
5043 #endif
5044 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || IS_ENABLED(CONFIG_NF_TABLES)
5045 	if (copy)
5046 		dst->nf_trace = src->nf_trace;
5047 #endif
5048 }
5049 
5050 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
5051 {
5052 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
5053 	nf_conntrack_put(skb_nfct(dst));
5054 #endif
5055 	dst->slow_gro = src->slow_gro;
5056 	__nf_copy(dst, src, true);
5057 }
5058 
5059 #ifdef CONFIG_NETWORK_SECMARK
5060 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
5061 {
5062 	to->secmark = from->secmark;
5063 }
5064 
5065 static inline void skb_init_secmark(struct sk_buff *skb)
5066 {
5067 	skb->secmark = 0;
5068 }
5069 #else
5070 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
5071 { }
5072 
5073 static inline void skb_init_secmark(struct sk_buff *skb)
5074 { }
5075 #endif
5076 
5077 static inline int secpath_exists(const struct sk_buff *skb)
5078 {
5079 #ifdef CONFIG_XFRM
5080 	return skb_ext_exist(skb, SKB_EXT_SEC_PATH);
5081 #else
5082 	return 0;
5083 #endif
5084 }
5085 
5086 static inline bool skb_irq_freeable(const struct sk_buff *skb)
5087 {
5088 	return !skb->destructor &&
5089 		!secpath_exists(skb) &&
5090 		!skb_nfct(skb) &&
5091 		!skb->_skb_refdst &&
5092 		!skb_has_frag_list(skb);
5093 }
5094 
5095 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
5096 {
5097 	skb->queue_mapping = queue_mapping;
5098 }
5099 
5100 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
5101 {
5102 	return skb->queue_mapping;
5103 }
5104 
5105 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
5106 {
5107 	to->queue_mapping = from->queue_mapping;
5108 }
5109 
5110 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
5111 {
5112 	skb->queue_mapping = rx_queue + 1;
5113 }
5114 
5115 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
5116 {
5117 	return skb->queue_mapping - 1;
5118 }
5119 
5120 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
5121 {
5122 	return skb->queue_mapping != 0;
5123 }
5124 
5125 static inline void skb_set_dst_pending_confirm(struct sk_buff *skb, u32 val)
5126 {
5127 	skb->dst_pending_confirm = val;
5128 }
5129 
5130 static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb)
5131 {
5132 	return skb->dst_pending_confirm != 0;
5133 }
5134 
5135 static inline struct sec_path *skb_sec_path(const struct sk_buff *skb)
5136 {
5137 #ifdef CONFIG_XFRM
5138 	return skb_ext_find(skb, SKB_EXT_SEC_PATH);
5139 #else
5140 	return NULL;
5141 #endif
5142 }
5143 
5144 static inline bool skb_is_gso(const struct sk_buff *skb)
5145 {
5146 	return skb_shinfo(skb)->gso_size;
5147 }
5148 
5149 /* Note: Should be called only if skb_is_gso(skb) is true */
5150 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
5151 {
5152 	return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
5153 }
5154 
5155 /* Note: Should be called only if skb_is_gso(skb) is true */
5156 static inline bool skb_is_gso_sctp(const struct sk_buff *skb)
5157 {
5158 	return skb_shinfo(skb)->gso_type & SKB_GSO_SCTP;
5159 }
5160 
5161 /* Note: Should be called only if skb_is_gso(skb) is true */
5162 static inline bool skb_is_gso_tcp(const struct sk_buff *skb)
5163 {
5164 	return skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6);
5165 }
5166 
5167 static inline void skb_gso_reset(struct sk_buff *skb)
5168 {
5169 	skb_shinfo(skb)->gso_size = 0;
5170 	skb_shinfo(skb)->gso_segs = 0;
5171 	skb_shinfo(skb)->gso_type = 0;
5172 }
5173 
5174 static inline void skb_increase_gso_size(struct skb_shared_info *shinfo,
5175 					 u16 increment)
5176 {
5177 	if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
5178 		return;
5179 	shinfo->gso_size += increment;
5180 }
5181 
5182 static inline void skb_decrease_gso_size(struct skb_shared_info *shinfo,
5183 					 u16 decrement)
5184 {
5185 	if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS))
5186 		return;
5187 	shinfo->gso_size -= decrement;
5188 }
5189 
5190 void __skb_warn_lro_forwarding(const struct sk_buff *skb);
5191 
5192 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
5193 {
5194 	/* LRO sets gso_size but not gso_type, whereas if GSO is really
5195 	 * wanted then gso_type will be set. */
5196 	const struct skb_shared_info *shinfo = skb_shinfo(skb);
5197 
5198 	if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
5199 	    unlikely(shinfo->gso_type == 0)) {
5200 		__skb_warn_lro_forwarding(skb);
5201 		return true;
5202 	}
5203 	return false;
5204 }
5205 
5206 static inline void skb_forward_csum(struct sk_buff *skb)
5207 {
5208 	/* Unfortunately we don't support this one.  Any brave souls? */
5209 	if (skb->ip_summed == CHECKSUM_COMPLETE)
5210 		skb->ip_summed = CHECKSUM_NONE;
5211 }
5212 
5213 /**
5214  * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
5215  * @skb: skb to check
5216  *
5217  * fresh skbs have their ip_summed set to CHECKSUM_NONE.
5218  * Instead of forcing ip_summed to CHECKSUM_NONE, we can
5219  * use this helper, to document places where we make this assertion.
5220  */
5221 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
5222 {
5223 	DEBUG_NET_WARN_ON_ONCE(skb->ip_summed != CHECKSUM_NONE);
5224 }
5225 
5226 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
5227 
5228 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
5229 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
5230 				     unsigned int transport_len,
5231 				     __sum16(*skb_chkf)(struct sk_buff *skb));
5232 
5233 /**
5234  * skb_head_is_locked - Determine if the skb->head is locked down
5235  * @skb: skb to check
5236  *
5237  * The head on skbs build around a head frag can be removed if they are
5238  * not cloned.  This function returns true if the skb head is locked down
5239  * due to either being allocated via kmalloc, or by being a clone with
5240  * multiple references to the head.
5241  */
5242 static inline bool skb_head_is_locked(const struct sk_buff *skb)
5243 {
5244 	return !skb->head_frag || skb_cloned(skb);
5245 }
5246 
5247 /* Local Checksum Offload.
5248  * Compute outer checksum based on the assumption that the
5249  * inner checksum will be offloaded later.
5250  * See Documentation/networking/checksum-offloads.rst for
5251  * explanation of how this works.
5252  * Fill in outer checksum adjustment (e.g. with sum of outer
5253  * pseudo-header) before calling.
5254  * Also ensure that inner checksum is in linear data area.
5255  */
5256 static inline __wsum lco_csum(struct sk_buff *skb)
5257 {
5258 	unsigned char *csum_start = skb_checksum_start(skb);
5259 	unsigned char *l4_hdr = skb_transport_header(skb);
5260 	__wsum partial;
5261 
5262 	/* Start with complement of inner checksum adjustment */
5263 	partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
5264 						    skb->csum_offset));
5265 
5266 	/* Add in checksum of our headers (incl. outer checksum
5267 	 * adjustment filled in by caller) and return result.
5268 	 */
5269 	return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
5270 }
5271 
5272 static inline bool skb_is_redirected(const struct sk_buff *skb)
5273 {
5274 	return skb->redirected;
5275 }
5276 
5277 static inline void skb_set_redirected(struct sk_buff *skb, bool from_ingress)
5278 {
5279 	skb->redirected = 1;
5280 #ifdef CONFIG_NET_REDIRECT
5281 	skb->from_ingress = from_ingress;
5282 	if (skb->from_ingress)
5283 		skb_clear_tstamp(skb);
5284 #endif
5285 }
5286 
5287 static inline void skb_reset_redirect(struct sk_buff *skb)
5288 {
5289 	skb->redirected = 0;
5290 }
5291 
5292 static inline void skb_set_redirected_noclear(struct sk_buff *skb,
5293 					      bool from_ingress)
5294 {
5295 	skb->redirected = 1;
5296 #ifdef CONFIG_NET_REDIRECT
5297 	skb->from_ingress = from_ingress;
5298 #endif
5299 }
5300 
5301 static inline bool skb_csum_is_sctp(struct sk_buff *skb)
5302 {
5303 #if IS_ENABLED(CONFIG_IP_SCTP)
5304 	return skb->csum_not_inet;
5305 #else
5306 	return 0;
5307 #endif
5308 }
5309 
5310 static inline void skb_reset_csum_not_inet(struct sk_buff *skb)
5311 {
5312 	skb->ip_summed = CHECKSUM_NONE;
5313 #if IS_ENABLED(CONFIG_IP_SCTP)
5314 	skb->csum_not_inet = 0;
5315 #endif
5316 }
5317 
5318 static inline void skb_set_kcov_handle(struct sk_buff *skb,
5319 				       const u64 kcov_handle)
5320 {
5321 #ifdef CONFIG_KCOV
5322 	skb->kcov_handle = kcov_handle;
5323 #endif
5324 }
5325 
5326 static inline u64 skb_get_kcov_handle(struct sk_buff *skb)
5327 {
5328 #ifdef CONFIG_KCOV
5329 	return skb->kcov_handle;
5330 #else
5331 	return 0;
5332 #endif
5333 }
5334 
5335 static inline void skb_mark_for_recycle(struct sk_buff *skb)
5336 {
5337 #ifdef CONFIG_PAGE_POOL
5338 	skb->pp_recycle = 1;
5339 #endif
5340 }
5341 
5342 ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
5343 			     ssize_t maxsize);
5344 
5345 #endif	/* __KERNEL__ */
5346 #endif	/* _LINUX_SKBUFF_H */
5347