xref: /openbmc/linux/include/net/ip.h (revision f9a82c48)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Definitions for the IP module.
7  *
8  * Version:	@(#)ip.h	1.0.2	05/07/93
9  *
10  * Authors:	Ross Biro
11  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *		Alan Cox, <gw4pts@gw4pts.ampr.org>
13  *
14  * Changes:
15  *		Mike McLagan    :       Routing by source
16  *
17  *		This program is free software; you can redistribute it and/or
18  *		modify it under the terms of the GNU General Public License
19  *		as published by the Free Software Foundation; either version
20  *		2 of the License, or (at your option) any later version.
21  */
22 #ifndef _IP_H
23 #define _IP_H
24 
25 #include <linux/types.h>
26 #include <linux/ip.h>
27 #include <linux/in.h>
28 #include <linux/skbuff.h>
29 #include <linux/jhash.h>
30 
31 #include <net/inet_sock.h>
32 #include <net/route.h>
33 #include <net/snmp.h>
34 #include <net/flow.h>
35 #include <net/flow_dissector.h>
36 #include <net/netns/hash.h>
37 
38 #define IPV4_MAX_PMTU		65535U		/* RFC 2675, Section 5.1 */
39 #define IPV4_MIN_MTU		68			/* RFC 791 */
40 
41 struct sock;
42 
43 struct inet_skb_parm {
44 	int			iif;
45 	struct ip_options	opt;		/* Compiled IP options		*/
46 	u16			flags;
47 
48 #define IPSKB_FORWARDED		BIT(0)
49 #define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)
50 #define IPSKB_XFRM_TRANSFORMED	BIT(2)
51 #define IPSKB_FRAG_COMPLETE	BIT(3)
52 #define IPSKB_REROUTED		BIT(4)
53 #define IPSKB_DOREDIRECT	BIT(5)
54 #define IPSKB_FRAG_PMTU		BIT(6)
55 #define IPSKB_L3SLAVE		BIT(7)
56 
57 	u16			frag_max_size;
58 };
59 
60 static inline bool ipv4_l3mdev_skb(u16 flags)
61 {
62 	return !!(flags & IPSKB_L3SLAVE);
63 }
64 
65 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
66 {
67 	return ip_hdr(skb)->ihl * 4;
68 }
69 
70 struct ipcm_cookie {
71 	struct sockcm_cookie	sockc;
72 	__be32			addr;
73 	int			oif;
74 	struct ip_options_rcu	*opt;
75 	__u8			ttl;
76 	__s16			tos;
77 	char			priority;
78 	__u16			gso_size;
79 };
80 
81 static inline void ipcm_init(struct ipcm_cookie *ipcm)
82 {
83 	*ipcm = (struct ipcm_cookie) { .tos = -1 };
84 }
85 
86 static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
87 				const struct inet_sock *inet)
88 {
89 	ipcm_init(ipcm);
90 
91 	ipcm->sockc.tsflags = inet->sk.sk_tsflags;
92 	ipcm->oif = inet->sk.sk_bound_dev_if;
93 	ipcm->addr = inet->inet_saddr;
94 }
95 
96 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
97 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
98 
99 /* return enslaved device index if relevant */
100 static inline int inet_sdif(struct sk_buff *skb)
101 {
102 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
103 	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
104 		return IPCB(skb)->iif;
105 #endif
106 	return 0;
107 }
108 
109 /* Special input handler for packets caught by router alert option.
110    They are selected only by protocol field, and then processed likely
111    local ones; but only if someone wants them! Otherwise, router
112    not running rsvpd will kill RSVP.
113 
114    It is user level problem, what it will make with them.
115    I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
116    but receiver should be enough clever f.e. to forward mtrace requests,
117    sent to multicast group to reach destination designated router.
118  */
119 
120 struct ip_ra_chain {
121 	struct ip_ra_chain __rcu *next;
122 	struct sock		*sk;
123 	union {
124 		void			(*destructor)(struct sock *);
125 		struct sock		*saved_sk;
126 	};
127 	struct rcu_head		rcu;
128 };
129 
130 /* IP flags. */
131 #define IP_CE		0x8000		/* Flag: "Congestion"		*/
132 #define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
133 #define IP_MF		0x2000		/* Flag: "More Fragments"	*/
134 #define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/
135 
136 #define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/
137 
138 struct msghdr;
139 struct net_device;
140 struct packet_type;
141 struct rtable;
142 struct sockaddr;
143 
144 int igmp_mc_init(void);
145 
146 /*
147  *	Functions provided by ip.c
148  */
149 
150 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
151 			  __be32 saddr, __be32 daddr,
152 			  struct ip_options_rcu *opt);
153 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
154 	   struct net_device *orig_dev);
155 void ip_list_rcv(struct list_head *head, struct packet_type *pt,
156 		 struct net_device *orig_dev);
157 int ip_local_deliver(struct sk_buff *skb);
158 void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
159 int ip_mr_input(struct sk_buff *skb);
160 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
161 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
162 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
163 		   int (*output)(struct net *, struct sock *, struct sk_buff *));
164 void ip_send_check(struct iphdr *ip);
165 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
166 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
167 
168 int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
169 		    __u8 tos);
170 void ip_init(void);
171 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
172 		   int getfrag(void *from, char *to, int offset, int len,
173 			       int odd, struct sk_buff *skb),
174 		   void *from, int len, int protolen,
175 		   struct ipcm_cookie *ipc,
176 		   struct rtable **rt,
177 		   unsigned int flags);
178 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
179 		       struct sk_buff *skb);
180 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
181 		       int offset, size_t size, int flags);
182 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
183 			      struct sk_buff_head *queue,
184 			      struct inet_cork *cork);
185 int ip_send_skb(struct net *net, struct sk_buff *skb);
186 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
187 void ip_flush_pending_frames(struct sock *sk);
188 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
189 			    int getfrag(void *from, char *to, int offset,
190 					int len, int odd, struct sk_buff *skb),
191 			    void *from, int length, int transhdrlen,
192 			    struct ipcm_cookie *ipc, struct rtable **rtp,
193 			    struct inet_cork *cork, unsigned int flags);
194 
195 static inline int ip_queue_xmit(struct sock *sk, struct sk_buff *skb,
196 				struct flowi *fl)
197 {
198 	return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
199 }
200 
201 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
202 {
203 	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
204 }
205 
206 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
207 {
208 	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
209 }
210 
211 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
212 {
213 	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
214 }
215 
216 /* datagram.c */
217 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
218 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
219 
220 void ip4_datagram_release_cb(struct sock *sk);
221 
222 struct ip_reply_arg {
223 	struct kvec iov[1];
224 	int	    flags;
225 	__wsum 	    csum;
226 	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
227 				/* -1 if not needed */
228 	int	    bound_dev_if;
229 	u8  	    tos;
230 	kuid_t	    uid;
231 };
232 
233 #define IP_REPLY_ARG_NOSRCCHECK 1
234 
235 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
236 {
237 	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
238 }
239 
240 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
241 			   const struct ip_options *sopt,
242 			   __be32 daddr, __be32 saddr,
243 			   const struct ip_reply_arg *arg,
244 			   unsigned int len);
245 
246 #define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
247 #define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)
248 #define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
249 #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
250 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
251 #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
252 #define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
253 #define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)
254 #define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
255 #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
256 
257 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
258 unsigned long snmp_fold_field(void __percpu *mib, int offt);
259 #if BITS_PER_LONG==32
260 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
261 			 size_t syncp_offset);
262 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
263 #else
264 static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
265 					size_t syncp_offset)
266 {
267 	return snmp_get_cpu_field(mib, cpu, offct);
268 
269 }
270 
271 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
272 {
273 	return snmp_fold_field(mib, offt);
274 }
275 #endif
276 
277 #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
278 { \
279 	int i, c; \
280 	for_each_possible_cpu(c) { \
281 		for (i = 0; stats_list[i].name; i++) \
282 			buff64[i] += snmp_get_cpu_field64( \
283 					mib_statistic, \
284 					c, stats_list[i].entry, \
285 					offset); \
286 	} \
287 }
288 
289 #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
290 { \
291 	int i, c; \
292 	for_each_possible_cpu(c) { \
293 		for (i = 0; stats_list[i].name; i++) \
294 			buff[i] += snmp_get_cpu_field( \
295 						mib_statistic, \
296 						c, stats_list[i].entry); \
297 	} \
298 }
299 
300 void inet_get_local_port_range(struct net *net, int *low, int *high);
301 
302 #ifdef CONFIG_SYSCTL
303 static inline int inet_is_local_reserved_port(struct net *net, int port)
304 {
305 	if (!net->ipv4.sysctl_local_reserved_ports)
306 		return 0;
307 	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
308 }
309 
310 static inline bool sysctl_dev_name_is_allowed(const char *name)
311 {
312 	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
313 }
314 
315 static inline int inet_prot_sock(struct net *net)
316 {
317 	return net->ipv4.sysctl_ip_prot_sock;
318 }
319 
320 #else
321 static inline int inet_is_local_reserved_port(struct net *net, int port)
322 {
323 	return 0;
324 }
325 
326 static inline int inet_prot_sock(struct net *net)
327 {
328 	return PROT_SOCK;
329 }
330 #endif
331 
332 __be32 inet_current_timestamp(void);
333 
334 /* From inetpeer.c */
335 extern int inet_peer_threshold;
336 extern int inet_peer_minttl;
337 extern int inet_peer_maxttl;
338 
339 void ipfrag_init(void);
340 
341 void ip_static_sysctl_init(void);
342 
343 #define IP4_REPLY_MARK(net, mark) \
344 	((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
345 
346 static inline bool ip_is_fragment(const struct iphdr *iph)
347 {
348 	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
349 }
350 
351 #ifdef CONFIG_INET
352 #include <net/dst.h>
353 
354 /* The function in 2.2 was invalid, producing wrong result for
355  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
356 static inline
357 int ip_decrease_ttl(struct iphdr *iph)
358 {
359 	u32 check = (__force u32)iph->check;
360 	check += (__force u32)htons(0x0100);
361 	iph->check = (__force __sum16)(check + (check>=0xFFFF));
362 	return --iph->ttl;
363 }
364 
365 static inline int ip_mtu_locked(const struct dst_entry *dst)
366 {
367 	const struct rtable *rt = (const struct rtable *)dst;
368 
369 	return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
370 }
371 
372 static inline
373 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
374 {
375 	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
376 
377 	return  pmtudisc == IP_PMTUDISC_DO ||
378 		(pmtudisc == IP_PMTUDISC_WANT &&
379 		 !ip_mtu_locked(dst));
380 }
381 
382 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
383 {
384 	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
385 	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
386 }
387 
388 static inline bool ip_sk_use_pmtu(const struct sock *sk)
389 {
390 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
391 }
392 
393 static inline bool ip_sk_ignore_df(const struct sock *sk)
394 {
395 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
396 	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
397 }
398 
399 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
400 						    bool forwarding)
401 {
402 	struct net *net = dev_net(dst->dev);
403 
404 	if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
405 	    ip_mtu_locked(dst) ||
406 	    !forwarding)
407 		return dst_mtu(dst);
408 
409 	return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
410 }
411 
412 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
413 					  const struct sk_buff *skb)
414 {
415 	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
416 		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
417 
418 		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
419 	}
420 
421 	return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
422 }
423 
424 struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
425 					int fc_mx_len,
426 					struct netlink_ext_ack *extack);
427 static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
428 {
429 	if (fib_metrics != &dst_default_metrics &&
430 	    refcount_dec_and_test(&fib_metrics->refcnt))
431 		kfree(fib_metrics);
432 }
433 
434 /* ipv4 and ipv6 both use refcounted metrics if it is not the default */
435 static inline
436 void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
437 {
438 	dst_init_metrics(dst, fib_metrics->metrics, true);
439 
440 	if (fib_metrics != &dst_default_metrics) {
441 		dst->_metrics |= DST_METRICS_REFCOUNTED;
442 		refcount_inc(&fib_metrics->refcnt);
443 	}
444 }
445 
446 static inline
447 void ip_dst_metrics_put(struct dst_entry *dst)
448 {
449 	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
450 
451 	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
452 		kfree(p);
453 }
454 
455 u32 ip_idents_reserve(u32 hash, int segs);
456 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
457 
458 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
459 					struct sock *sk, int segs)
460 {
461 	struct iphdr *iph = ip_hdr(skb);
462 
463 	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
464 		/* This is only to work around buggy Windows95/2000
465 		 * VJ compression implementations.  If the ID field
466 		 * does not change, they drop every other packet in
467 		 * a TCP stream using header compression.
468 		 */
469 		if (sk && inet_sk(sk)->inet_daddr) {
470 			iph->id = htons(inet_sk(sk)->inet_id);
471 			inet_sk(sk)->inet_id += segs;
472 		} else {
473 			iph->id = 0;
474 		}
475 	} else {
476 		__ip_select_ident(net, iph, segs);
477 	}
478 }
479 
480 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
481 				   struct sock *sk)
482 {
483 	ip_select_ident_segs(net, skb, sk, 1);
484 }
485 
486 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
487 {
488 	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
489 				  skb->len, proto, 0);
490 }
491 
492 /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
493  * Equivalent to :	flow->v4addrs.src = iph->saddr;
494  *			flow->v4addrs.dst = iph->daddr;
495  */
496 static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
497 					    const struct iphdr *iph)
498 {
499 	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
500 		     offsetof(typeof(flow->addrs), v4addrs.src) +
501 			      sizeof(flow->addrs.v4addrs.src));
502 	memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
503 	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
504 }
505 
506 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
507 {
508 	const struct iphdr *iph = skb_gro_network_header(skb);
509 
510 	return csum_tcpudp_nofold(iph->saddr, iph->daddr,
511 				  skb_gro_len(skb), proto, 0);
512 }
513 
514 /*
515  *	Map a multicast IP onto multicast MAC for type ethernet.
516  */
517 
518 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
519 {
520 	__u32 addr=ntohl(naddr);
521 	buf[0]=0x01;
522 	buf[1]=0x00;
523 	buf[2]=0x5e;
524 	buf[5]=addr&0xFF;
525 	addr>>=8;
526 	buf[4]=addr&0xFF;
527 	addr>>=8;
528 	buf[3]=addr&0x7F;
529 }
530 
531 /*
532  *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
533  *	Leave P_Key as 0 to be filled in by driver.
534  */
535 
536 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
537 {
538 	__u32 addr;
539 	unsigned char scope = broadcast[5] & 0xF;
540 
541 	buf[0]  = 0;		/* Reserved */
542 	buf[1]  = 0xff;		/* Multicast QPN */
543 	buf[2]  = 0xff;
544 	buf[3]  = 0xff;
545 	addr    = ntohl(naddr);
546 	buf[4]  = 0xff;
547 	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
548 	buf[6]  = 0x40;		/* IPv4 signature */
549 	buf[7]  = 0x1b;
550 	buf[8]  = broadcast[8];		/* P_Key */
551 	buf[9]  = broadcast[9];
552 	buf[10] = 0;
553 	buf[11] = 0;
554 	buf[12] = 0;
555 	buf[13] = 0;
556 	buf[14] = 0;
557 	buf[15] = 0;
558 	buf[19] = addr & 0xff;
559 	addr  >>= 8;
560 	buf[18] = addr & 0xff;
561 	addr  >>= 8;
562 	buf[17] = addr & 0xff;
563 	addr  >>= 8;
564 	buf[16] = addr & 0x0f;
565 }
566 
567 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
568 {
569 	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
570 		memcpy(buf, broadcast, 4);
571 	else
572 		memcpy(buf, &naddr, sizeof(naddr));
573 }
574 
575 #if IS_ENABLED(CONFIG_IPV6)
576 #include <linux/ipv6.h>
577 #endif
578 
579 static __inline__ void inet_reset_saddr(struct sock *sk)
580 {
581 	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
582 #if IS_ENABLED(CONFIG_IPV6)
583 	if (sk->sk_family == PF_INET6) {
584 		struct ipv6_pinfo *np = inet6_sk(sk);
585 
586 		memset(&np->saddr, 0, sizeof(np->saddr));
587 		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
588 	}
589 #endif
590 }
591 
592 #endif
593 
594 static inline unsigned int ipv4_addr_hash(__be32 ip)
595 {
596 	return (__force unsigned int) ip;
597 }
598 
599 static inline u32 ipv4_portaddr_hash(const struct net *net,
600 				     __be32 saddr,
601 				     unsigned int port)
602 {
603 	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
604 }
605 
606 bool ip_call_ra_chain(struct sk_buff *skb);
607 
608 /*
609  *	Functions provided by ip_fragment.c
610  */
611 
612 enum ip_defrag_users {
613 	IP_DEFRAG_LOCAL_DELIVER,
614 	IP_DEFRAG_CALL_RA_CHAIN,
615 	IP_DEFRAG_CONNTRACK_IN,
616 	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
617 	IP_DEFRAG_CONNTRACK_OUT,
618 	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
619 	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
620 	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
621 	IP_DEFRAG_VS_IN,
622 	IP_DEFRAG_VS_OUT,
623 	IP_DEFRAG_VS_FWD,
624 	IP_DEFRAG_AF_PACKET,
625 	IP_DEFRAG_MACVLAN,
626 };
627 
628 /* Return true if the value of 'user' is between 'lower_bond'
629  * and 'upper_bond' inclusively.
630  */
631 static inline bool ip_defrag_user_in_between(u32 user,
632 					     enum ip_defrag_users lower_bond,
633 					     enum ip_defrag_users upper_bond)
634 {
635 	return user >= lower_bond && user <= upper_bond;
636 }
637 
638 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
639 #ifdef CONFIG_INET
640 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
641 #else
642 static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
643 {
644 	return skb;
645 }
646 #endif
647 
648 /*
649  *	Functions provided by ip_forward.c
650  */
651 
652 int ip_forward(struct sk_buff *skb);
653 
654 /*
655  *	Functions provided by ip_options.c
656  */
657 
658 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
659 		      __be32 daddr, struct rtable *rt, int is_frag);
660 
661 int __ip_options_echo(struct net *net, struct ip_options *dopt,
662 		      struct sk_buff *skb, const struct ip_options *sopt);
663 static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
664 				  struct sk_buff *skb)
665 {
666 	return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
667 }
668 
669 void ip_options_fragment(struct sk_buff *skb);
670 int __ip_options_compile(struct net *net, struct ip_options *opt,
671 			 struct sk_buff *skb, __be32 *info);
672 int ip_options_compile(struct net *net, struct ip_options *opt,
673 		       struct sk_buff *skb);
674 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
675 		   unsigned char *data, int optlen);
676 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
677 			     unsigned char __user *data, int optlen);
678 void ip_options_undo(struct ip_options *opt);
679 void ip_forward_options(struct sk_buff *skb);
680 int ip_options_rcv_srr(struct sk_buff *skb);
681 
682 /*
683  *	Functions provided by ip_sockglue.c
684  */
685 
686 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
687 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
688 			 struct sk_buff *skb, int tlen, int offset);
689 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
690 		 struct ipcm_cookie *ipc, bool allow_ipv6);
691 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
692 		  unsigned int optlen);
693 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
694 		  int __user *optlen);
695 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
696 			 char __user *optval, unsigned int optlen);
697 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
698 			 char __user *optval, int __user *optlen);
699 int ip_ra_control(struct sock *sk, unsigned char on,
700 		  void (*destructor)(struct sock *));
701 
702 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
703 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
704 		   u32 info, u8 *payload);
705 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
706 		    u32 info);
707 
708 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
709 {
710 	ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
711 }
712 
713 bool icmp_global_allow(void);
714 extern int sysctl_icmp_msgs_per_sec;
715 extern int sysctl_icmp_msgs_burst;
716 
717 #ifdef CONFIG_PROC_FS
718 int ip_misc_proc_init(void);
719 #endif
720 
721 int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
722 				struct netlink_ext_ack *extack);
723 
724 #endif	/* _IP_H */
725