summaryrefslogtreecommitdiff
path: root/include/net/ip.h
blob: b71e88507c4a0907011c41e1ed0148eb873b5186 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Definitions for the IP module.
 *
 * Version:	@(#)ip.h	1.0.2	05/07/93
 *
 * Authors:	Ross Biro
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *
 * Changes:
 *		Mike McLagan    :       Routing by source
 */
#ifndef _IP_H
#define _IP_H

#include <linux/types.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/jhash.h>
#include <linux/sockptr.h>
#include <linux/static_key.h>

#include <net/inet_sock.h>
#include <net/route.h>
#include <net/snmp.h>
#include <net/flow.h>
#include <net/flow_dissector.h>
#include <net/netns/hash.h>
#include <net/lwtunnel.h>

#define IPV4_MAX_PMTU		65535U		/* RFC 2675, Section 5.1 */
#define IPV4_MIN_MTU		68			/* RFC 791 */

extern unsigned int sysctl_fib_sync_mem;
extern unsigned int sysctl_fib_sync_mem_min;
extern unsigned int sysctl_fib_sync_mem_max;

struct sock;

struct inet_skb_parm {
	int			iif;
	struct ip_options	opt;		/* Compiled IP options		*/
	u16			flags;

#define IPSKB_FORWARDED		BIT(0)
#define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)
#define IPSKB_XFRM_TRANSFORMED	BIT(2)
#define IPSKB_FRAG_COMPLETE	BIT(3)
#define IPSKB_REROUTED		BIT(4)
#define IPSKB_DOREDIRECT	BIT(5)
#define IPSKB_FRAG_PMTU		BIT(6)
#define IPSKB_L3SLAVE		BIT(7)

	u16			frag_max_size;
};

static inline bool ipv4_l3mdev_skb(u16 flags)
{
	return !!(flags & IPSKB_L3SLAVE);
}

static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
{
	return ip_hdr(skb)->ihl * 4;
}

struct ipcm_cookie {
	struct sockcm_cookie	sockc;
	__be32			addr;
	int			oif;
	struct ip_options_rcu	*opt;
	__u8			ttl;
	__s16			tos;
	char			priority;
	__u16			gso_size;
};

static inline void ipcm_init(struct ipcm_cookie *ipcm)
{
	*ipcm = (struct ipcm_cookie) { .tos = -1 };
}

static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
				const struct inet_sock *inet)
{
	ipcm_init(ipcm);

	ipcm->sockc.mark = inet->sk.sk_mark;
	ipcm->sockc.tsflags = inet->sk.sk_tsflags;
	ipcm->oif = inet->sk.sk_bound_dev_if;
	ipcm->addr = inet->inet_saddr;
}

#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))

/* return enslaved device index if relevant */
static inline int inet_sdif(const struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
		return IPCB(skb)->iif;
#endif
	return 0;
}

/* Special input handler for packets caught by router alert option.
   They are selected only by protocol field, and then processed likely
   local ones; but only if someone wants them! Otherwise, router
   not running rsvpd will kill RSVP.

   It is user level problem, what it will make with them.
   I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
   but receiver should be enough clever f.e. to forward mtrace requests,
   sent to multicast group to reach destination designated router.
 */

struct ip_ra_chain {
	struct ip_ra_chain __rcu *next;
	struct sock		*sk;
	union {
		void			(*destructor)(struct sock *);
		struct sock		*saved_sk;
	};
	struct rcu_head		rcu;
};

/* IP flags. */
#define IP_CE		0x8000		/* Flag: "Congestion"		*/
#define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
#define IP_MF		0x2000		/* Flag: "More Fragments"	*/
#define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/

#define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/

struct msghdr;
struct net_device;
struct packet_type;
struct rtable;
struct sockaddr;

int igmp_mc_init(void);

/*
 *	Functions provided by ip.c
 */

int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
			  __be32 saddr, __be32 daddr,
			  struct ip_options_rcu *opt, u8 tos);
int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
	   struct net_device *orig_dev);
void ip_list_rcv(struct list_head *head, struct packet_type *pt,
		 struct net_device *orig_dev);
int ip_local_deliver(struct sk_buff *skb);
void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
int ip_mr_input(struct sk_buff *skb);
int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
		   int (*output)(struct net *, struct sock *, struct sk_buff *));

struct ip_fraglist_iter {
	struct sk_buff	*frag;
	struct iphdr	*iph;
	int		offset;
	unsigned int	hlen;
};

void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
		      unsigned int hlen, struct ip_fraglist_iter *iter);
void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);

static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
{
	struct sk_buff *skb = iter->frag;

	iter->frag = skb->next;
	skb_mark_not_on_list(skb);

	return skb;
}

struct ip_frag_state {
	bool		DF;
	unsigned int	hlen;
	unsigned int	ll_rs;
	unsigned int	mtu;
	unsigned int	left;
	int		offset;
	int		ptr;
	__be16		not_last_frag;
};

void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
		  unsigned int mtu, bool DF, struct ip_frag_state *state);
struct sk_buff *ip_frag_next(struct sk_buff *skb,
			     struct ip_frag_state *state);

void ip_send_check(struct iphdr *ip);
int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);

int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
		    __u8 tos);
void ip_init(void);
int ip_append_data(struct sock *sk, struct flowi4 *fl4,
		   int getfrag(void *from, char *to, int offset, int len,
			       int odd, struct sk_buff *skb),
		   void *from, int len, int protolen,
		   struct ipcm_cookie *ipc,
		   struct rtable **rt,
		   unsigned int flags);
int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
		       struct sk_buff *skb);
ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
		       int offset, size_t size, int flags);
struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
			      struct sk_buff_head *queue,
			      struct inet_cork *cork);
int ip_send_skb(struct net *net, struct sk_buff *skb);
int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
void ip_flush_pending_frames(struct sock *sk);
struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
			    int getfrag(void *from, char *to, int offset,
					int len, int odd, struct sk_buff *skb),
			    void *from, int length, int transhdrlen,
			    struct ipcm_cookie *ipc, struct rtable **rtp,
			    struct inet_cork *cork, unsigned int flags);

int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);

static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
{
	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
}

static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
{
	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
}

static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
{
	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
}

/* datagram.c */
int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);

void ip4_datagram_release_cb(struct sock *sk);

struct ip_reply_arg {
	struct kvec iov[1];
	int	    flags;
	__wsum 	    csum;
	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
				/* -1 if not needed */
	int	    bound_dev_if;
	u8  	    tos;
	kuid_t	    uid;
};

#define IP_REPLY_ARG_NOSRCCHECK 1

static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
{
	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
}

void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
			   const struct ip_options *sopt,
			   __be32 daddr, __be32 saddr,
			   const struct ip_reply_arg *arg,
			   unsigned int len, u64 transmit_time);

#define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
#define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
#define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)
#define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)

static inline u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
{
	return  *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
}

unsigned long snmp_fold_field(void __percpu *mib, int offt);
#if BITS_PER_LONG==32
u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
			 size_t syncp_offset);
u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
#else
static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
					size_t syncp_offset)
{
	return snmp_get_cpu_field(mib, cpu, offct);

}

static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
{
	return snmp_fold_field(mib, offt);
}
#endif

#define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
{ \
	int i, c; \
	for_each_possible_cpu(c) { \
		for (i = 0; stats_list[i].name; i++) \
			buff64[i] += snmp_get_cpu_field64( \
					mib_statistic, \
					c, stats_list[i].entry, \
					offset); \
	} \
}

#define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
{ \
	int i, c; \
	for_each_possible_cpu(c) { \
		for (i = 0; stats_list[i].name; i++) \
			buff[i] += snmp_get_cpu_field( \
						mib_statistic, \
						c, stats_list[i].entry); \
	} \
}

void inet_get_local_port_range(struct net *net, int *low, int *high);

#ifdef CONFIG_SYSCTL
static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
{
	if (!net->ipv4.sysctl_local_reserved_ports)
		return false;
	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
}

static inline bool sysctl_dev_name_is_allowed(const char *name)
{
	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
}

static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
{
	return port < net->ipv4.sysctl_ip_prot_sock;
}

#else
static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
{
	return false;
}

static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
{
	return port < PROT_SOCK;
}
#endif

__be32 inet_current_timestamp(void);

/* From inetpeer.c */
extern int inet_peer_threshold;
extern int inet_peer_minttl;
extern int inet_peer_maxttl;

void ipfrag_init(void);

void ip_static_sysctl_init(void);

#define IP4_REPLY_MARK(net, mark) \
	((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)

static inline bool ip_is_fragment(const struct iphdr *iph)
{
	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
}

#ifdef CONFIG_INET
#include <net/dst.h>

/* The function in 2.2 was invalid, producing wrong result for
 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
static inline
int ip_decrease_ttl(struct iphdr *iph)
{
	u32 check = (__force u32)iph->check;
	check += (__force u32)htons(0x0100);
	iph->check = (__force __sum16)(check + (check>=0xFFFF));
	return --iph->ttl;
}

static inline int ip_mtu_locked(const struct dst_entry *dst)
{
	const struct rtable *rt = (const struct rtable *)dst;

	return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
}

static inline
int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
{
	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);

	return  pmtudisc == IP_PMTUDISC_DO ||
		(pmtudisc == IP_PMTUDISC_WANT &&
		 !ip_mtu_locked(dst));
}

static inline bool ip_sk_accept_pmtu(const struct sock *sk)
{
	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
}

static inline bool ip_sk_use_pmtu(const struct sock *sk)
{
	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
}

static inline bool ip_sk_ignore_df(const struct sock *sk)
{
	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
}

static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
						    bool forwarding)
{
	const struct rtable *rt = container_of(dst, struct rtable, dst);
	struct net *net = dev_net(dst->dev);
	unsigned int mtu;

	if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
	    ip_mtu_locked(dst) ||
	    !forwarding) {
		mtu = rt->rt_pmtu;
		if (mtu && time_before(jiffies, rt->dst.expires))
			goto out;
	}

	/* 'forwarding = true' case should always honour route mtu */
	mtu = dst_metric_raw(dst, RTAX_MTU);
	if (mtu)
		goto out;

	mtu = READ_ONCE(dst->dev->mtu);

	if (unlikely(ip_mtu_locked(dst))) {
		if (rt->rt_uses_gateway && mtu > 576)
			mtu = 576;
	}

out:
	mtu = min_t(unsigned int, mtu, IP_MAX_MTU);

	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
}

static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
					  const struct sk_buff *skb)
{
	unsigned int mtu;

	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;

		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
	}

	mtu = min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
	return mtu - lwtunnel_headroom(skb_dst(skb)->lwtstate, mtu);
}

struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
					int fc_mx_len,
					struct netlink_ext_ack *extack);
static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
{
	if (fib_metrics != &dst_default_metrics &&
	    refcount_dec_and_test(&fib_metrics->refcnt))
		kfree(fib_metrics);
}

/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
static inline
void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
{
	dst_init_metrics(dst, fib_metrics->metrics, true);

	if (fib_metrics != &dst_default_metrics) {
		dst->_metrics |= DST_METRICS_REFCOUNTED;
		refcount_inc(&fib_metrics->refcnt);
	}
}

static inline
void ip_dst_metrics_put(struct dst_entry *dst)
{
	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);

	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
		kfree(p);
}

u32 ip_idents_reserve(u32 hash, int segs);
void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);

static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
					struct sock *sk, int segs)
{
	struct iphdr *iph = ip_hdr(skb);

	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
		/* This is only to work around buggy Windows95/2000
		 * VJ compression implementations.  If the ID field
		 * does not change, they drop every other packet in
		 * a TCP stream using header compression.
		 */
		if (sk && inet_sk(sk)->inet_daddr) {
			iph->id = htons(inet_sk(sk)->inet_id);
			inet_sk(sk)->inet_id += segs;
		} else {
			iph->id = 0;
		}
	} else {
		__ip_select_ident(net, iph, segs);
	}
}

static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
				   struct sock *sk)
{
	ip_select_ident_segs(net, skb, sk, 1);
}

static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
{
	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
				  skb->len, proto, 0);
}

/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 * Equivalent to :	flow->v4addrs.src = iph->saddr;
 *			flow->v4addrs.dst = iph->daddr;
 */
static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
					    const struct iphdr *iph)
{
	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
		     offsetof(typeof(flow->addrs), v4addrs.src) +
			      sizeof(flow->addrs.v4addrs.src));
	memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
}

static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
{
	const struct iphdr *iph = skb_gro_network_header(skb);

	return csum_tcpudp_nofold(iph->saddr, iph->daddr,
				  skb_gro_len(skb), proto, 0);
}

/*
 *	Map a multicast IP onto multicast MAC for type ethernet.
 */

static inline void ip_eth_mc_map(__be32 naddr, char *buf)
{
	__u32 addr=ntohl(naddr);
	buf[0]=0x01;
	buf[1]=0x00;
	buf[2]=0x5e;
	buf[5]=addr&0xFF;
	addr>>=8;
	buf[4]=addr&0xFF;
	addr>>=8;
	buf[3]=addr&0x7F;
}

/*
 *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 *	Leave P_Key as 0 to be filled in by driver.
 */

static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
{
	__u32 addr;
	unsigned char scope = broadcast[5] & 0xF;

	buf[0]  = 0;		/* Reserved */
	buf[1]  = 0xff;		/* Multicast QPN */
	buf[2]  = 0xff;
	buf[3]  = 0xff;
	addr    = ntohl(naddr);
	buf[4]  = 0xff;
	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
	buf[6]  = 0x40;		/* IPv4 signature */
	buf[7]  = 0x1b;
	buf[8]  = broadcast[8];		/* P_Key */
	buf[9]  = broadcast[9];
	buf[10] = 0;
	buf[11] = 0;
	buf[12] = 0;
	buf[13] = 0;
	buf[14] = 0;
	buf[15] = 0;
	buf[19] = addr & 0xff;
	addr  >>= 8;
	buf[18] = addr & 0xff;
	addr  >>= 8;
	buf[17] = addr & 0xff;
	addr  >>= 8;
	buf[16] = addr & 0x0f;
}

static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
{
	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
		memcpy(buf, broadcast, 4);
	else
		memcpy(buf, &naddr, sizeof(naddr));
}

#if IS_ENABLED(CONFIG_IPV6)
#include <linux/ipv6.h>
#endif

static __inline__ void inet_reset_saddr(struct sock *sk)
{
	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
#if IS_ENABLED(CONFIG_IPV6)
	if (sk->sk_family == PF_INET6) {
		struct ipv6_pinfo *np = inet6_sk(sk);

		memset(&np->saddr, 0, sizeof(np->saddr));
		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
	}
#endif
}

#endif

static inline unsigned int ipv4_addr_hash(__be32 ip)
{
	return (__force unsigned int) ip;
}

static inline u32 ipv4_portaddr_hash(const struct net *net,
				     __be32 saddr,
				     unsigned int port)
{
	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
}

bool ip_call_ra_chain(struct sk_buff *skb);

/*
 *	Functions provided by ip_fragment.c
 */

enum ip_defrag_users {
	IP_DEFRAG_LOCAL_DELIVER,
	IP_DEFRAG_CALL_RA_CHAIN,
	IP_DEFRAG_CONNTRACK_IN,
	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
	IP_DEFRAG_CONNTRACK_OUT,
	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
	IP_DEFRAG_VS_IN,
	IP_DEFRAG_VS_OUT,
	IP_DEFRAG_VS_FWD,
	IP_DEFRAG_AF_PACKET,
	IP_DEFRAG_MACVLAN,
};

/* Return true if the value of 'user' is between 'lower_bond'
 * and 'upper_bond' inclusively.
 */
static inline bool ip_defrag_user_in_between(u32 user,
					     enum ip_defrag_users lower_bond,
					     enum ip_defrag_users upper_bond)
{
	return user >= lower_bond && user <= upper_bond;
}

int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
#ifdef CONFIG_INET
struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
#else
static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
{
	return skb;
}
#endif

/*
 *	Functions provided by ip_forward.c
 */

int ip_forward(struct sk_buff *skb);

/*
 *	Functions provided by ip_options.c
 */

void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
		      __be32 daddr, struct rtable *rt, int is_frag);

int __ip_options_echo(struct net *net, struct ip_options *dopt,
		      struct sk_buff *skb, const struct ip_options *sopt);
static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
				  struct sk_buff *skb)
{
	return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
}

void ip_options_fragment(struct sk_buff *skb);
int __ip_options_compile(struct net *net, struct ip_options *opt,
			 struct sk_buff *skb, __be32 *info);
int ip_options_compile(struct net *net, struct ip_options *opt,
		       struct sk_buff *skb);
int ip_options_get(struct net *net, struct ip_options_rcu **optp,
		   sockptr_t data, int optlen);
void ip_options_undo(struct ip_options *opt);
void ip_forward_options(struct sk_buff *skb);
int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);

/*
 *	Functions provided by ip_sockglue.c
 */

void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
			 struct sk_buff *skb, int tlen, int offset);
int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
		 struct ipcm_cookie *ipc, bool allow_ipv6);
DECLARE_STATIC_KEY_FALSE(ip4_min_ttl);
int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
		  unsigned int optlen);
int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
		  int __user *optlen);
int ip_ra_control(struct sock *sk, unsigned char on,
		  void (*destructor)(struct sock *));

int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
		   u32 info, u8 *payload);
void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
		    u32 info);

static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
{
	ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
}

bool icmp_global_allow(void);
extern int sysctl_icmp_msgs_per_sec;
extern int sysctl_icmp_msgs_burst;

#ifdef CONFIG_PROC_FS
int ip_misc_proc_init(void);
#endif

int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
				struct netlink_ext_ack *extack);

static inline bool inetdev_valid_mtu(unsigned int mtu)
{
	return likely(mtu >= IPV4_MIN_MTU);
}

void ip_sock_set_freebind(struct sock *sk);
int ip_sock_set_mtu_discover(struct sock *sk, int val);
void ip_sock_set_pktinfo(struct sock *sk);
void ip_sock_set_recverr(struct sock *sk);
void ip_sock_set_tos(struct sock *sk, int val);

#endif	/* _IP_H */