xref: /linux/include/net/ip.h (revision 02000b55850deeadffe433e4b4930a8831f477de)
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			tx_flags;
76 	__u8			ttl;
77 	__s16			tos;
78 	char			priority;
79 	__u16			gso_size;
80 };
81 
82 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
83 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
84 
85 /* return enslaved device index if relevant */
86 static inline int inet_sdif(struct sk_buff *skb)
87 {
88 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
89 	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
90 		return IPCB(skb)->iif;
91 #endif
92 	return 0;
93 }
94 
95 /* Special input handler for packets caught by router alert option.
96    They are selected only by protocol field, and then processed likely
97    local ones; but only if someone wants them! Otherwise, router
98    not running rsvpd will kill RSVP.
99 
100    It is user level problem, what it will make with them.
101    I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
102    but receiver should be enough clever f.e. to forward mtrace requests,
103    sent to multicast group to reach destination designated router.
104  */
105 
106 struct ip_ra_chain {
107 	struct ip_ra_chain __rcu *next;
108 	struct sock		*sk;
109 	union {
110 		void			(*destructor)(struct sock *);
111 		struct sock		*saved_sk;
112 	};
113 	struct rcu_head		rcu;
114 };
115 
116 /* IP flags. */
117 #define IP_CE		0x8000		/* Flag: "Congestion"		*/
118 #define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
119 #define IP_MF		0x2000		/* Flag: "More Fragments"	*/
120 #define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/
121 
122 #define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/
123 
124 struct msghdr;
125 struct net_device;
126 struct packet_type;
127 struct rtable;
128 struct sockaddr;
129 
130 int igmp_mc_init(void);
131 
132 /*
133  *	Functions provided by ip.c
134  */
135 
136 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
137 			  __be32 saddr, __be32 daddr,
138 			  struct ip_options_rcu *opt);
139 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
140 	   struct net_device *orig_dev);
141 void ip_list_rcv(struct list_head *head, struct packet_type *pt,
142 		 struct net_device *orig_dev);
143 int ip_local_deliver(struct sk_buff *skb);
144 int ip_mr_input(struct sk_buff *skb);
145 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
146 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
147 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
148 		   int (*output)(struct net *, struct sock *, struct sk_buff *));
149 void ip_send_check(struct iphdr *ip);
150 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
151 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
152 
153 int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
154 		    __u8 tos);
155 void ip_init(void);
156 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
157 		   int getfrag(void *from, char *to, int offset, int len,
158 			       int odd, struct sk_buff *skb),
159 		   void *from, int len, int protolen,
160 		   struct ipcm_cookie *ipc,
161 		   struct rtable **rt,
162 		   unsigned int flags);
163 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
164 		       struct sk_buff *skb);
165 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
166 		       int offset, size_t size, int flags);
167 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
168 			      struct sk_buff_head *queue,
169 			      struct inet_cork *cork);
170 int ip_send_skb(struct net *net, struct sk_buff *skb);
171 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
172 void ip_flush_pending_frames(struct sock *sk);
173 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
174 			    int getfrag(void *from, char *to, int offset,
175 					int len, int odd, struct sk_buff *skb),
176 			    void *from, int length, int transhdrlen,
177 			    struct ipcm_cookie *ipc, struct rtable **rtp,
178 			    struct inet_cork *cork, unsigned int flags);
179 
180 static inline int ip_queue_xmit(struct sock *sk, struct sk_buff *skb,
181 				struct flowi *fl)
182 {
183 	return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
184 }
185 
186 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
187 {
188 	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
189 }
190 
191 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
192 {
193 	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
194 }
195 
196 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
197 {
198 	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
199 }
200 
201 /* datagram.c */
202 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
203 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
204 
205 void ip4_datagram_release_cb(struct sock *sk);
206 
207 struct ip_reply_arg {
208 	struct kvec iov[1];
209 	int	    flags;
210 	__wsum 	    csum;
211 	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
212 				/* -1 if not needed */
213 	int	    bound_dev_if;
214 	u8  	    tos;
215 	kuid_t	    uid;
216 };
217 
218 #define IP_REPLY_ARG_NOSRCCHECK 1
219 
220 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
221 {
222 	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
223 }
224 
225 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
226 			   const struct ip_options *sopt,
227 			   __be32 daddr, __be32 saddr,
228 			   const struct ip_reply_arg *arg,
229 			   unsigned int len);
230 
231 #define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
232 #define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)
233 #define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
234 #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
235 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
236 #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
237 #define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
238 #define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)
239 #define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
240 #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
241 
242 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
243 unsigned long snmp_fold_field(void __percpu *mib, int offt);
244 #if BITS_PER_LONG==32
245 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
246 			 size_t syncp_offset);
247 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
248 #else
249 static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
250 					size_t syncp_offset)
251 {
252 	return snmp_get_cpu_field(mib, cpu, offct);
253 
254 }
255 
256 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
257 {
258 	return snmp_fold_field(mib, offt);
259 }
260 #endif
261 
262 #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
263 { \
264 	int i, c; \
265 	for_each_possible_cpu(c) { \
266 		for (i = 0; stats_list[i].name; i++) \
267 			buff64[i] += snmp_get_cpu_field64( \
268 					mib_statistic, \
269 					c, stats_list[i].entry, \
270 					offset); \
271 	} \
272 }
273 
274 #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
275 { \
276 	int i, c; \
277 	for_each_possible_cpu(c) { \
278 		for (i = 0; stats_list[i].name; i++) \
279 			buff[i] += snmp_get_cpu_field( \
280 						mib_statistic, \
281 						c, stats_list[i].entry); \
282 	} \
283 }
284 
285 void inet_get_local_port_range(struct net *net, int *low, int *high);
286 
287 #ifdef CONFIG_SYSCTL
288 static inline int inet_is_local_reserved_port(struct net *net, int port)
289 {
290 	if (!net->ipv4.sysctl_local_reserved_ports)
291 		return 0;
292 	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
293 }
294 
295 static inline bool sysctl_dev_name_is_allowed(const char *name)
296 {
297 	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
298 }
299 
300 static inline int inet_prot_sock(struct net *net)
301 {
302 	return net->ipv4.sysctl_ip_prot_sock;
303 }
304 
305 #else
306 static inline int inet_is_local_reserved_port(struct net *net, int port)
307 {
308 	return 0;
309 }
310 
311 static inline int inet_prot_sock(struct net *net)
312 {
313 	return PROT_SOCK;
314 }
315 #endif
316 
317 __be32 inet_current_timestamp(void);
318 
319 /* From inetpeer.c */
320 extern int inet_peer_threshold;
321 extern int inet_peer_minttl;
322 extern int inet_peer_maxttl;
323 
324 void ipfrag_init(void);
325 
326 void ip_static_sysctl_init(void);
327 
328 #define IP4_REPLY_MARK(net, mark) \
329 	((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
330 
331 static inline bool ip_is_fragment(const struct iphdr *iph)
332 {
333 	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
334 }
335 
336 #ifdef CONFIG_INET
337 #include <net/dst.h>
338 
339 /* The function in 2.2 was invalid, producing wrong result for
340  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
341 static inline
342 int ip_decrease_ttl(struct iphdr *iph)
343 {
344 	u32 check = (__force u32)iph->check;
345 	check += (__force u32)htons(0x0100);
346 	iph->check = (__force __sum16)(check + (check>=0xFFFF));
347 	return --iph->ttl;
348 }
349 
350 static inline int ip_mtu_locked(const struct dst_entry *dst)
351 {
352 	const struct rtable *rt = (const struct rtable *)dst;
353 
354 	return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
355 }
356 
357 static inline
358 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
359 {
360 	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
361 
362 	return  pmtudisc == IP_PMTUDISC_DO ||
363 		(pmtudisc == IP_PMTUDISC_WANT &&
364 		 !ip_mtu_locked(dst));
365 }
366 
367 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
368 {
369 	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
370 	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
371 }
372 
373 static inline bool ip_sk_use_pmtu(const struct sock *sk)
374 {
375 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
376 }
377 
378 static inline bool ip_sk_ignore_df(const struct sock *sk)
379 {
380 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
381 	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
382 }
383 
384 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
385 						    bool forwarding)
386 {
387 	struct net *net = dev_net(dst->dev);
388 
389 	if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
390 	    ip_mtu_locked(dst) ||
391 	    !forwarding)
392 		return dst_mtu(dst);
393 
394 	return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
395 }
396 
397 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
398 					  const struct sk_buff *skb)
399 {
400 	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
401 		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
402 
403 		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
404 	}
405 
406 	return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
407 }
408 
409 int ip_metrics_convert(struct net *net, struct nlattr *fc_mx, int fc_mx_len,
410 		       u32 *metrics);
411 
412 u32 ip_idents_reserve(u32 hash, int segs);
413 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
414 
415 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
416 					struct sock *sk, int segs)
417 {
418 	struct iphdr *iph = ip_hdr(skb);
419 
420 	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
421 		/* This is only to work around buggy Windows95/2000
422 		 * VJ compression implementations.  If the ID field
423 		 * does not change, they drop every other packet in
424 		 * a TCP stream using header compression.
425 		 */
426 		if (sk && inet_sk(sk)->inet_daddr) {
427 			iph->id = htons(inet_sk(sk)->inet_id);
428 			inet_sk(sk)->inet_id += segs;
429 		} else {
430 			iph->id = 0;
431 		}
432 	} else {
433 		__ip_select_ident(net, iph, segs);
434 	}
435 }
436 
437 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
438 				   struct sock *sk)
439 {
440 	ip_select_ident_segs(net, skb, sk, 1);
441 }
442 
443 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
444 {
445 	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
446 				  skb->len, proto, 0);
447 }
448 
449 /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
450  * Equivalent to :	flow->v4addrs.src = iph->saddr;
451  *			flow->v4addrs.dst = iph->daddr;
452  */
453 static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
454 					    const struct iphdr *iph)
455 {
456 	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
457 		     offsetof(typeof(flow->addrs), v4addrs.src) +
458 			      sizeof(flow->addrs.v4addrs.src));
459 	memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
460 	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
461 }
462 
463 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
464 {
465 	const struct iphdr *iph = skb_gro_network_header(skb);
466 
467 	return csum_tcpudp_nofold(iph->saddr, iph->daddr,
468 				  skb_gro_len(skb), proto, 0);
469 }
470 
471 /*
472  *	Map a multicast IP onto multicast MAC for type ethernet.
473  */
474 
475 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
476 {
477 	__u32 addr=ntohl(naddr);
478 	buf[0]=0x01;
479 	buf[1]=0x00;
480 	buf[2]=0x5e;
481 	buf[5]=addr&0xFF;
482 	addr>>=8;
483 	buf[4]=addr&0xFF;
484 	addr>>=8;
485 	buf[3]=addr&0x7F;
486 }
487 
488 /*
489  *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
490  *	Leave P_Key as 0 to be filled in by driver.
491  */
492 
493 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
494 {
495 	__u32 addr;
496 	unsigned char scope = broadcast[5] & 0xF;
497 
498 	buf[0]  = 0;		/* Reserved */
499 	buf[1]  = 0xff;		/* Multicast QPN */
500 	buf[2]  = 0xff;
501 	buf[3]  = 0xff;
502 	addr    = ntohl(naddr);
503 	buf[4]  = 0xff;
504 	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
505 	buf[6]  = 0x40;		/* IPv4 signature */
506 	buf[7]  = 0x1b;
507 	buf[8]  = broadcast[8];		/* P_Key */
508 	buf[9]  = broadcast[9];
509 	buf[10] = 0;
510 	buf[11] = 0;
511 	buf[12] = 0;
512 	buf[13] = 0;
513 	buf[14] = 0;
514 	buf[15] = 0;
515 	buf[19] = addr & 0xff;
516 	addr  >>= 8;
517 	buf[18] = addr & 0xff;
518 	addr  >>= 8;
519 	buf[17] = addr & 0xff;
520 	addr  >>= 8;
521 	buf[16] = addr & 0x0f;
522 }
523 
524 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
525 {
526 	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
527 		memcpy(buf, broadcast, 4);
528 	else
529 		memcpy(buf, &naddr, sizeof(naddr));
530 }
531 
532 #if IS_ENABLED(CONFIG_IPV6)
533 #include <linux/ipv6.h>
534 #endif
535 
536 static __inline__ void inet_reset_saddr(struct sock *sk)
537 {
538 	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
539 #if IS_ENABLED(CONFIG_IPV6)
540 	if (sk->sk_family == PF_INET6) {
541 		struct ipv6_pinfo *np = inet6_sk(sk);
542 
543 		memset(&np->saddr, 0, sizeof(np->saddr));
544 		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
545 	}
546 #endif
547 }
548 
549 #endif
550 
551 static inline unsigned int ipv4_addr_hash(__be32 ip)
552 {
553 	return (__force unsigned int) ip;
554 }
555 
556 static inline u32 ipv4_portaddr_hash(const struct net *net,
557 				     __be32 saddr,
558 				     unsigned int port)
559 {
560 	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
561 }
562 
563 bool ip_call_ra_chain(struct sk_buff *skb);
564 
565 /*
566  *	Functions provided by ip_fragment.c
567  */
568 
569 enum ip_defrag_users {
570 	IP_DEFRAG_LOCAL_DELIVER,
571 	IP_DEFRAG_CALL_RA_CHAIN,
572 	IP_DEFRAG_CONNTRACK_IN,
573 	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
574 	IP_DEFRAG_CONNTRACK_OUT,
575 	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
576 	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
577 	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
578 	IP_DEFRAG_VS_IN,
579 	IP_DEFRAG_VS_OUT,
580 	IP_DEFRAG_VS_FWD,
581 	IP_DEFRAG_AF_PACKET,
582 	IP_DEFRAG_MACVLAN,
583 };
584 
585 /* Return true if the value of 'user' is between 'lower_bond'
586  * and 'upper_bond' inclusively.
587  */
588 static inline bool ip_defrag_user_in_between(u32 user,
589 					     enum ip_defrag_users lower_bond,
590 					     enum ip_defrag_users upper_bond)
591 {
592 	return user >= lower_bond && user <= upper_bond;
593 }
594 
595 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
596 #ifdef CONFIG_INET
597 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
598 #else
599 static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
600 {
601 	return skb;
602 }
603 #endif
604 
605 /*
606  *	Functions provided by ip_forward.c
607  */
608 
609 int ip_forward(struct sk_buff *skb);
610 
611 /*
612  *	Functions provided by ip_options.c
613  */
614 
615 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
616 		      __be32 daddr, struct rtable *rt, int is_frag);
617 
618 int __ip_options_echo(struct net *net, struct ip_options *dopt,
619 		      struct sk_buff *skb, const struct ip_options *sopt);
620 static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
621 				  struct sk_buff *skb)
622 {
623 	return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
624 }
625 
626 void ip_options_fragment(struct sk_buff *skb);
627 int ip_options_compile(struct net *net, struct ip_options *opt,
628 		       struct sk_buff *skb);
629 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
630 		   unsigned char *data, int optlen);
631 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
632 			     unsigned char __user *data, int optlen);
633 void ip_options_undo(struct ip_options *opt);
634 void ip_forward_options(struct sk_buff *skb);
635 int ip_options_rcv_srr(struct sk_buff *skb);
636 
637 /*
638  *	Functions provided by ip_sockglue.c
639  */
640 
641 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
642 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
643 			 struct sk_buff *skb, int tlen, int offset);
644 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
645 		 struct ipcm_cookie *ipc, bool allow_ipv6);
646 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
647 		  unsigned int optlen);
648 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
649 		  int __user *optlen);
650 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
651 			 char __user *optval, unsigned int optlen);
652 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
653 			 char __user *optval, int __user *optlen);
654 int ip_ra_control(struct sock *sk, unsigned char on,
655 		  void (*destructor)(struct sock *));
656 
657 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
658 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
659 		   u32 info, u8 *payload);
660 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
661 		    u32 info);
662 
663 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
664 {
665 	ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
666 }
667 
668 bool icmp_global_allow(void);
669 extern int sysctl_icmp_msgs_per_sec;
670 extern int sysctl_icmp_msgs_burst;
671 
672 #ifdef CONFIG_PROC_FS
673 int ip_misc_proc_init(void);
674 #endif
675 
676 int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto,
677 				struct netlink_ext_ack *extack);
678 
679 #endif	/* _IP_H */
680