xref: /openbmc/linux/include/net/ip.h (revision 68198dca)
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 
30 #include <net/inet_sock.h>
31 #include <net/route.h>
32 #include <net/snmp.h>
33 #include <net/flow.h>
34 #include <net/flow_dissector.h>
35 
36 #define IPV4_MAX_PMTU		65535U		/* RFC 2675, Section 5.1 */
37 #define IPV4_MIN_MTU		68			/* RFC 791 */
38 
39 struct sock;
40 
41 struct inet_skb_parm {
42 	int			iif;
43 	struct ip_options	opt;		/* Compiled IP options		*/
44 	u16			flags;
45 
46 #define IPSKB_FORWARDED		BIT(0)
47 #define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)
48 #define IPSKB_XFRM_TRANSFORMED	BIT(2)
49 #define IPSKB_FRAG_COMPLETE	BIT(3)
50 #define IPSKB_REROUTED		BIT(4)
51 #define IPSKB_DOREDIRECT	BIT(5)
52 #define IPSKB_FRAG_PMTU		BIT(6)
53 #define IPSKB_L3SLAVE		BIT(7)
54 
55 	u16			frag_max_size;
56 };
57 
58 static inline bool ipv4_l3mdev_skb(u16 flags)
59 {
60 	return !!(flags & IPSKB_L3SLAVE);
61 }
62 
63 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
64 {
65 	return ip_hdr(skb)->ihl * 4;
66 }
67 
68 struct ipcm_cookie {
69 	struct sockcm_cookie	sockc;
70 	__be32			addr;
71 	int			oif;
72 	struct ip_options_rcu	*opt;
73 	__u8			tx_flags;
74 	__u8			ttl;
75 	__s16			tos;
76 	char			priority;
77 };
78 
79 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
80 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
81 
82 /* return enslaved device index if relevant */
83 static inline int inet_sdif(struct sk_buff *skb)
84 {
85 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
86 	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
87 		return IPCB(skb)->iif;
88 #endif
89 	return 0;
90 }
91 
92 struct ip_ra_chain {
93 	struct ip_ra_chain __rcu *next;
94 	struct sock		*sk;
95 	union {
96 		void			(*destructor)(struct sock *);
97 		struct sock		*saved_sk;
98 	};
99 	struct rcu_head		rcu;
100 };
101 
102 extern struct ip_ra_chain __rcu *ip_ra_chain;
103 
104 /* IP flags. */
105 #define IP_CE		0x8000		/* Flag: "Congestion"		*/
106 #define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
107 #define IP_MF		0x2000		/* Flag: "More Fragments"	*/
108 #define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/
109 
110 #define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/
111 
112 struct msghdr;
113 struct net_device;
114 struct packet_type;
115 struct rtable;
116 struct sockaddr;
117 
118 int igmp_mc_init(void);
119 
120 /*
121  *	Functions provided by ip.c
122  */
123 
124 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
125 			  __be32 saddr, __be32 daddr,
126 			  struct ip_options_rcu *opt);
127 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
128 	   struct net_device *orig_dev);
129 int ip_local_deliver(struct sk_buff *skb);
130 int ip_mr_input(struct sk_buff *skb);
131 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
132 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
133 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
134 		   int (*output)(struct net *, struct sock *, struct sk_buff *));
135 void ip_send_check(struct iphdr *ip);
136 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
137 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
138 
139 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
140 void ip_init(void);
141 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
142 		   int getfrag(void *from, char *to, int offset, int len,
143 			       int odd, struct sk_buff *skb),
144 		   void *from, int len, int protolen,
145 		   struct ipcm_cookie *ipc,
146 		   struct rtable **rt,
147 		   unsigned int flags);
148 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
149 		       struct sk_buff *skb);
150 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
151 		       int offset, size_t size, int flags);
152 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
153 			      struct sk_buff_head *queue,
154 			      struct inet_cork *cork);
155 int ip_send_skb(struct net *net, struct sk_buff *skb);
156 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
157 void ip_flush_pending_frames(struct sock *sk);
158 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
159 			    int getfrag(void *from, char *to, int offset,
160 					int len, int odd, struct sk_buff *skb),
161 			    void *from, int length, int transhdrlen,
162 			    struct ipcm_cookie *ipc, struct rtable **rtp,
163 			    unsigned int flags);
164 
165 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
166 {
167 	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
168 }
169 
170 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
171 {
172 	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
173 }
174 
175 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
176 {
177 	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
178 }
179 
180 /* datagram.c */
181 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
182 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
183 
184 void ip4_datagram_release_cb(struct sock *sk);
185 
186 struct ip_reply_arg {
187 	struct kvec iov[1];
188 	int	    flags;
189 	__wsum 	    csum;
190 	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
191 				/* -1 if not needed */
192 	int	    bound_dev_if;
193 	u8  	    tos;
194 	kuid_t	    uid;
195 };
196 
197 #define IP_REPLY_ARG_NOSRCCHECK 1
198 
199 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
200 {
201 	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
202 }
203 
204 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
205 			   const struct ip_options *sopt,
206 			   __be32 daddr, __be32 saddr,
207 			   const struct ip_reply_arg *arg,
208 			   unsigned int len);
209 
210 #define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
211 #define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)
212 #define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
213 #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
214 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
215 #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
216 #define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
217 #define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)
218 #define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
219 #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
220 
221 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
222 unsigned long snmp_fold_field(void __percpu *mib, int offt);
223 #if BITS_PER_LONG==32
224 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
225 			 size_t syncp_offset);
226 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
227 #else
228 static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
229 					size_t syncp_offset)
230 {
231 	return snmp_get_cpu_field(mib, cpu, offct);
232 
233 }
234 
235 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
236 {
237 	return snmp_fold_field(mib, offt);
238 }
239 #endif
240 
241 #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
242 { \
243 	int i, c; \
244 	for_each_possible_cpu(c) { \
245 		for (i = 0; stats_list[i].name; i++) \
246 			buff64[i] += snmp_get_cpu_field64( \
247 					mib_statistic, \
248 					c, stats_list[i].entry, \
249 					offset); \
250 	} \
251 }
252 
253 #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
254 { \
255 	int i, c; \
256 	for_each_possible_cpu(c) { \
257 		for (i = 0; stats_list[i].name; i++) \
258 			buff[i] += snmp_get_cpu_field( \
259 						mib_statistic, \
260 						c, stats_list[i].entry); \
261 	} \
262 }
263 
264 void inet_get_local_port_range(struct net *net, int *low, int *high);
265 
266 #ifdef CONFIG_SYSCTL
267 static inline int inet_is_local_reserved_port(struct net *net, int port)
268 {
269 	if (!net->ipv4.sysctl_local_reserved_ports)
270 		return 0;
271 	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
272 }
273 
274 static inline bool sysctl_dev_name_is_allowed(const char *name)
275 {
276 	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
277 }
278 
279 static inline int inet_prot_sock(struct net *net)
280 {
281 	return net->ipv4.sysctl_ip_prot_sock;
282 }
283 
284 #else
285 static inline int inet_is_local_reserved_port(struct net *net, int port)
286 {
287 	return 0;
288 }
289 
290 static inline int inet_prot_sock(struct net *net)
291 {
292 	return PROT_SOCK;
293 }
294 #endif
295 
296 __be32 inet_current_timestamp(void);
297 
298 /* From inetpeer.c */
299 extern int inet_peer_threshold;
300 extern int inet_peer_minttl;
301 extern int inet_peer_maxttl;
302 
303 void ipfrag_init(void);
304 
305 void ip_static_sysctl_init(void);
306 
307 #define IP4_REPLY_MARK(net, mark) \
308 	((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
309 
310 static inline bool ip_is_fragment(const struct iphdr *iph)
311 {
312 	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
313 }
314 
315 #ifdef CONFIG_INET
316 #include <net/dst.h>
317 
318 /* The function in 2.2 was invalid, producing wrong result for
319  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
320 static inline
321 int ip_decrease_ttl(struct iphdr *iph)
322 {
323 	u32 check = (__force u32)iph->check;
324 	check += (__force u32)htons(0x0100);
325 	iph->check = (__force __sum16)(check + (check>=0xFFFF));
326 	return --iph->ttl;
327 }
328 
329 static inline
330 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
331 {
332 	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
333 
334 	return  pmtudisc == IP_PMTUDISC_DO ||
335 		(pmtudisc == IP_PMTUDISC_WANT &&
336 		 !(dst_metric_locked(dst, RTAX_MTU)));
337 }
338 
339 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
340 {
341 	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
342 	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
343 }
344 
345 static inline bool ip_sk_use_pmtu(const struct sock *sk)
346 {
347 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
348 }
349 
350 static inline bool ip_sk_ignore_df(const struct sock *sk)
351 {
352 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
353 	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
354 }
355 
356 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
357 						    bool forwarding)
358 {
359 	struct net *net = dev_net(dst->dev);
360 
361 	if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
362 	    dst_metric_locked(dst, RTAX_MTU) ||
363 	    !forwarding)
364 		return dst_mtu(dst);
365 
366 	return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
367 }
368 
369 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
370 					  const struct sk_buff *skb)
371 {
372 	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
373 		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
374 
375 		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
376 	}
377 
378 	return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
379 }
380 
381 u32 ip_idents_reserve(u32 hash, int segs);
382 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
383 
384 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
385 					struct sock *sk, int segs)
386 {
387 	struct iphdr *iph = ip_hdr(skb);
388 
389 	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
390 		/* This is only to work around buggy Windows95/2000
391 		 * VJ compression implementations.  If the ID field
392 		 * does not change, they drop every other packet in
393 		 * a TCP stream using header compression.
394 		 */
395 		if (sk && inet_sk(sk)->inet_daddr) {
396 			iph->id = htons(inet_sk(sk)->inet_id);
397 			inet_sk(sk)->inet_id += segs;
398 		} else {
399 			iph->id = 0;
400 		}
401 	} else {
402 		__ip_select_ident(net, iph, segs);
403 	}
404 }
405 
406 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
407 				   struct sock *sk)
408 {
409 	ip_select_ident_segs(net, skb, sk, 1);
410 }
411 
412 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
413 {
414 	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
415 				  skb->len, proto, 0);
416 }
417 
418 /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
419  * Equivalent to :	flow->v4addrs.src = iph->saddr;
420  *			flow->v4addrs.dst = iph->daddr;
421  */
422 static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
423 					    const struct iphdr *iph)
424 {
425 	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
426 		     offsetof(typeof(flow->addrs), v4addrs.src) +
427 			      sizeof(flow->addrs.v4addrs.src));
428 	memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
429 	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
430 }
431 
432 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
433 {
434 	const struct iphdr *iph = skb_gro_network_header(skb);
435 
436 	return csum_tcpudp_nofold(iph->saddr, iph->daddr,
437 				  skb_gro_len(skb), proto, 0);
438 }
439 
440 /*
441  *	Map a multicast IP onto multicast MAC for type ethernet.
442  */
443 
444 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
445 {
446 	__u32 addr=ntohl(naddr);
447 	buf[0]=0x01;
448 	buf[1]=0x00;
449 	buf[2]=0x5e;
450 	buf[5]=addr&0xFF;
451 	addr>>=8;
452 	buf[4]=addr&0xFF;
453 	addr>>=8;
454 	buf[3]=addr&0x7F;
455 }
456 
457 /*
458  *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
459  *	Leave P_Key as 0 to be filled in by driver.
460  */
461 
462 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
463 {
464 	__u32 addr;
465 	unsigned char scope = broadcast[5] & 0xF;
466 
467 	buf[0]  = 0;		/* Reserved */
468 	buf[1]  = 0xff;		/* Multicast QPN */
469 	buf[2]  = 0xff;
470 	buf[3]  = 0xff;
471 	addr    = ntohl(naddr);
472 	buf[4]  = 0xff;
473 	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
474 	buf[6]  = 0x40;		/* IPv4 signature */
475 	buf[7]  = 0x1b;
476 	buf[8]  = broadcast[8];		/* P_Key */
477 	buf[9]  = broadcast[9];
478 	buf[10] = 0;
479 	buf[11] = 0;
480 	buf[12] = 0;
481 	buf[13] = 0;
482 	buf[14] = 0;
483 	buf[15] = 0;
484 	buf[19] = addr & 0xff;
485 	addr  >>= 8;
486 	buf[18] = addr & 0xff;
487 	addr  >>= 8;
488 	buf[17] = addr & 0xff;
489 	addr  >>= 8;
490 	buf[16] = addr & 0x0f;
491 }
492 
493 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
494 {
495 	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
496 		memcpy(buf, broadcast, 4);
497 	else
498 		memcpy(buf, &naddr, sizeof(naddr));
499 }
500 
501 #if IS_ENABLED(CONFIG_IPV6)
502 #include <linux/ipv6.h>
503 #endif
504 
505 static __inline__ void inet_reset_saddr(struct sock *sk)
506 {
507 	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
508 #if IS_ENABLED(CONFIG_IPV6)
509 	if (sk->sk_family == PF_INET6) {
510 		struct ipv6_pinfo *np = inet6_sk(sk);
511 
512 		memset(&np->saddr, 0, sizeof(np->saddr));
513 		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
514 	}
515 #endif
516 }
517 
518 #endif
519 
520 static inline unsigned int ipv4_addr_hash(__be32 ip)
521 {
522 	return (__force unsigned int) ip;
523 }
524 
525 bool ip_call_ra_chain(struct sk_buff *skb);
526 
527 /*
528  *	Functions provided by ip_fragment.c
529  */
530 
531 enum ip_defrag_users {
532 	IP_DEFRAG_LOCAL_DELIVER,
533 	IP_DEFRAG_CALL_RA_CHAIN,
534 	IP_DEFRAG_CONNTRACK_IN,
535 	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
536 	IP_DEFRAG_CONNTRACK_OUT,
537 	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
538 	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
539 	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
540 	IP_DEFRAG_VS_IN,
541 	IP_DEFRAG_VS_OUT,
542 	IP_DEFRAG_VS_FWD,
543 	IP_DEFRAG_AF_PACKET,
544 	IP_DEFRAG_MACVLAN,
545 };
546 
547 /* Return true if the value of 'user' is between 'lower_bond'
548  * and 'upper_bond' inclusively.
549  */
550 static inline bool ip_defrag_user_in_between(u32 user,
551 					     enum ip_defrag_users lower_bond,
552 					     enum ip_defrag_users upper_bond)
553 {
554 	return user >= lower_bond && user <= upper_bond;
555 }
556 
557 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
558 #ifdef CONFIG_INET
559 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
560 #else
561 static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
562 {
563 	return skb;
564 }
565 #endif
566 int ip_frag_mem(struct net *net);
567 
568 /*
569  *	Functions provided by ip_forward.c
570  */
571 
572 int ip_forward(struct sk_buff *skb);
573 
574 /*
575  *	Functions provided by ip_options.c
576  */
577 
578 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
579 		      __be32 daddr, struct rtable *rt, int is_frag);
580 
581 int __ip_options_echo(struct net *net, struct ip_options *dopt,
582 		      struct sk_buff *skb, const struct ip_options *sopt);
583 static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
584 				  struct sk_buff *skb)
585 {
586 	return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
587 }
588 
589 void ip_options_fragment(struct sk_buff *skb);
590 int ip_options_compile(struct net *net, struct ip_options *opt,
591 		       struct sk_buff *skb);
592 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
593 		   unsigned char *data, int optlen);
594 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
595 			     unsigned char __user *data, int optlen);
596 void ip_options_undo(struct ip_options *opt);
597 void ip_forward_options(struct sk_buff *skb);
598 int ip_options_rcv_srr(struct sk_buff *skb);
599 
600 /*
601  *	Functions provided by ip_sockglue.c
602  */
603 
604 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
605 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
606 			 struct sk_buff *skb, int tlen, int offset);
607 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
608 		 struct ipcm_cookie *ipc, bool allow_ipv6);
609 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
610 		  unsigned int optlen);
611 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
612 		  int __user *optlen);
613 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
614 			 char __user *optval, unsigned int optlen);
615 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
616 			 char __user *optval, int __user *optlen);
617 int ip_ra_control(struct sock *sk, unsigned char on,
618 		  void (*destructor)(struct sock *));
619 
620 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
621 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
622 		   u32 info, u8 *payload);
623 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
624 		    u32 info);
625 
626 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
627 {
628 	ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
629 }
630 
631 bool icmp_global_allow(void);
632 extern int sysctl_icmp_msgs_per_sec;
633 extern int sysctl_icmp_msgs_burst;
634 
635 #ifdef CONFIG_PROC_FS
636 int ip_misc_proc_init(void);
637 #endif
638 
639 #endif	/* _IP_H */
640