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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
35struct sock;
36
37struct inet_skb_parm {
38 struct ip_options opt; /* Compiled IP options */
39 unsigned char flags;
40
41#define IPSKB_FORWARDED 1
42#define IPSKB_XFRM_TUNNEL_SIZE 2
43#define IPSKB_XFRM_TRANSFORMED 4
44#define IPSKB_FRAG_COMPLETE 8
45#define IPSKB_REROUTED 16
46
47 u16 frag_max_size;
48};
49
50static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
51{
52 return ip_hdr(skb)->ihl * 4;
53}
54
55struct ipcm_cookie {
56 __be32 addr;
57 int oif;
58 struct ip_options_rcu *opt;
59 __u8 tx_flags;
60 __u8 ttl;
61 __s16 tos;
62 char priority;
63};
64
65#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
66#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
67
68struct ip_ra_chain {
69 struct ip_ra_chain __rcu *next;
70 struct sock *sk;
71 union {
72 void (*destructor)(struct sock *);
73 struct sock *saved_sk;
74 };
75 struct rcu_head rcu;
76};
77
78extern struct ip_ra_chain __rcu *ip_ra_chain;
79
80/* IP flags. */
81#define IP_CE 0x8000 /* Flag: "Congestion" */
82#define IP_DF 0x4000 /* Flag: "Don't Fragment" */
83#define IP_MF 0x2000 /* Flag: "More Fragments" */
84#define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
85
86#define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
87
88struct msghdr;
89struct net_device;
90struct packet_type;
91struct rtable;
92struct sockaddr;
93
94int igmp_mc_init(void);
95
96/*
97 * Functions provided by ip.c
98 */
99
100int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
101 __be32 saddr, __be32 daddr,
102 struct ip_options_rcu *opt);
103int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
104 struct net_device *orig_dev);
105int ip_local_deliver(struct sk_buff *skb);
106int ip_mr_input(struct sk_buff *skb);
107int ip_output(struct sock *sk, struct sk_buff *skb);
108int ip_mc_output(struct sock *sk, struct sk_buff *skb);
109int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
110int ip_do_nat(struct sk_buff *skb);
111void ip_send_check(struct iphdr *ip);
112int __ip_local_out(struct sk_buff *skb);
113int ip_local_out_sk(struct sock *sk, struct sk_buff *skb);
114static inline int ip_local_out(struct sk_buff *skb)
115{
116 return ip_local_out_sk(skb->sk, skb);
117}
118
119int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
120void ip_init(void);
121int ip_append_data(struct sock *sk, struct flowi4 *fl4,
122 int getfrag(void *from, char *to, int offset, int len,
123 int odd, struct sk_buff *skb),
124 void *from, int len, int protolen,
125 struct ipcm_cookie *ipc,
126 struct rtable **rt,
127 unsigned int flags);
128int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
129 struct sk_buff *skb);
130ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
131 int offset, size_t size, int flags);
132struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
133 struct sk_buff_head *queue,
134 struct inet_cork *cork);
135int ip_send_skb(struct net *net, struct sk_buff *skb);
136int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
137void ip_flush_pending_frames(struct sock *sk);
138struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
139 int getfrag(void *from, char *to, int offset,
140 int len, int odd, struct sk_buff *skb),
141 void *from, int length, int transhdrlen,
142 struct ipcm_cookie *ipc, struct rtable **rtp,
143 unsigned int flags);
144
145static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
146{
147 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
148}
149
150static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
151{
152 return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
153}
154
155static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
156{
157 return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
158}
159
160/* datagram.c */
161int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
162
163void ip4_datagram_release_cb(struct sock *sk);
164
165struct ip_reply_arg {
166 struct kvec iov[1];
167 int flags;
168 __wsum csum;
169 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
170 /* -1 if not needed */
171 int bound_dev_if;
172 u8 tos;
173};
174
175#define IP_REPLY_ARG_NOSRCCHECK 1
176
177static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
178{
179 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
180}
181
182void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
183 __be32 saddr, const struct ip_reply_arg *arg,
184 unsigned int len);
185
186#define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
187#define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
188#define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
189#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
190#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
191#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
192#define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
193#define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
194#define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
195#define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
196#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
197#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
198
199unsigned long snmp_fold_field(void __percpu *mib, int offt);
200#if BITS_PER_LONG==32
201u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
202#else
203static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
204{
205 return snmp_fold_field(mib, offt);
206}
207#endif
208
209void inet_get_local_port_range(struct net *net, int *low, int *high);
210
211#ifdef CONFIG_SYSCTL
212static inline int inet_is_local_reserved_port(struct net *net, int port)
213{
214 if (!net->ipv4.sysctl_local_reserved_ports)
215 return 0;
216 return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
217}
218#else
219static inline int inet_is_local_reserved_port(struct net *net, int port)
220{
221 return 0;
222}
223#endif
224
225extern int sysctl_ip_nonlocal_bind;
226
227/* From inetpeer.c */
228extern int inet_peer_threshold;
229extern int inet_peer_minttl;
230extern int inet_peer_maxttl;
231
232/* From ip_input.c */
233extern int sysctl_ip_early_demux;
234
235/* From ip_output.c */
236extern int sysctl_ip_dynaddr;
237
238void ipfrag_init(void);
239
240void ip_static_sysctl_init(void);
241
242#define IP4_REPLY_MARK(net, mark) \
243 ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
244
245static inline bool ip_is_fragment(const struct iphdr *iph)
246{
247 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
248}
249
250#ifdef CONFIG_INET
251#include <net/dst.h>
252
253/* The function in 2.2 was invalid, producing wrong result for
254 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
255static inline
256int ip_decrease_ttl(struct iphdr *iph)
257{
258 u32 check = (__force u32)iph->check;
259 check += (__force u32)htons(0x0100);
260 iph->check = (__force __sum16)(check + (check>=0xFFFF));
261 return --iph->ttl;
262}
263
264static inline
265int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
266{
267 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
268 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
269 !(dst_metric_locked(dst, RTAX_MTU)));
270}
271
272static inline bool ip_sk_accept_pmtu(const struct sock *sk)
273{
274 return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
275 inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
276}
277
278static inline bool ip_sk_use_pmtu(const struct sock *sk)
279{
280 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
281}
282
283static inline bool ip_sk_ignore_df(const struct sock *sk)
284{
285 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
286 inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
287}
288
289static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
290 bool forwarding)
291{
292 struct net *net = dev_net(dst->dev);
293
294 if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
295 dst_metric_locked(dst, RTAX_MTU) ||
296 !forwarding)
297 return dst_mtu(dst);
298
299 return min(dst->dev->mtu, IP_MAX_MTU);
300}
301
302static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb)
303{
304 if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
305 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
306 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
307 } else {
308 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
309 }
310}
311
312u32 ip_idents_reserve(u32 hash, int segs);
313void __ip_select_ident(struct iphdr *iph, int segs);
314
315static inline void ip_select_ident_segs(struct sk_buff *skb, struct sock *sk, int segs)
316{
317 struct iphdr *iph = ip_hdr(skb);
318
319 if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
320 /* This is only to work around buggy Windows95/2000
321 * VJ compression implementations. If the ID field
322 * does not change, they drop every other packet in
323 * a TCP stream using header compression.
324 */
325 if (sk && inet_sk(sk)->inet_daddr) {
326 iph->id = htons(inet_sk(sk)->inet_id);
327 inet_sk(sk)->inet_id += segs;
328 } else {
329 iph->id = 0;
330 }
331 } else {
332 __ip_select_ident(iph, segs);
333 }
334}
335
336static inline void ip_select_ident(struct sk_buff *skb, struct sock *sk)
337{
338 ip_select_ident_segs(skb, sk, 1);
339}
340
341static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
342{
343 return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
344 skb->len, proto, 0);
345}
346
347/*
348 * Map a multicast IP onto multicast MAC for type ethernet.
349 */
350
351static inline void ip_eth_mc_map(__be32 naddr, char *buf)
352{
353 __u32 addr=ntohl(naddr);
354 buf[0]=0x01;
355 buf[1]=0x00;
356 buf[2]=0x5e;
357 buf[5]=addr&0xFF;
358 addr>>=8;
359 buf[4]=addr&0xFF;
360 addr>>=8;
361 buf[3]=addr&0x7F;
362}
363
364/*
365 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
366 * Leave P_Key as 0 to be filled in by driver.
367 */
368
369static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
370{
371 __u32 addr;
372 unsigned char scope = broadcast[5] & 0xF;
373
374 buf[0] = 0; /* Reserved */
375 buf[1] = 0xff; /* Multicast QPN */
376 buf[2] = 0xff;
377 buf[3] = 0xff;
378 addr = ntohl(naddr);
379 buf[4] = 0xff;
380 buf[5] = 0x10 | scope; /* scope from broadcast address */
381 buf[6] = 0x40; /* IPv4 signature */
382 buf[7] = 0x1b;
383 buf[8] = broadcast[8]; /* P_Key */
384 buf[9] = broadcast[9];
385 buf[10] = 0;
386 buf[11] = 0;
387 buf[12] = 0;
388 buf[13] = 0;
389 buf[14] = 0;
390 buf[15] = 0;
391 buf[19] = addr & 0xff;
392 addr >>= 8;
393 buf[18] = addr & 0xff;
394 addr >>= 8;
395 buf[17] = addr & 0xff;
396 addr >>= 8;
397 buf[16] = addr & 0x0f;
398}
399
400static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
401{
402 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
403 memcpy(buf, broadcast, 4);
404 else
405 memcpy(buf, &naddr, sizeof(naddr));
406}
407
408#if IS_ENABLED(CONFIG_IPV6)
409#include <linux/ipv6.h>
410#endif
411
412static __inline__ void inet_reset_saddr(struct sock *sk)
413{
414 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
415#if IS_ENABLED(CONFIG_IPV6)
416 if (sk->sk_family == PF_INET6) {
417 struct ipv6_pinfo *np = inet6_sk(sk);
418
419 memset(&np->saddr, 0, sizeof(np->saddr));
420 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
421 }
422#endif
423}
424
425#endif
426
427static inline int sk_mc_loop(struct sock *sk)
428{
429 if (!sk)
430 return 1;
431 switch (sk->sk_family) {
432 case AF_INET:
433 return inet_sk(sk)->mc_loop;
434#if IS_ENABLED(CONFIG_IPV6)
435 case AF_INET6:
436 return inet6_sk(sk)->mc_loop;
437#endif
438 }
439 WARN_ON(1);
440 return 1;
441}
442
443bool ip_call_ra_chain(struct sk_buff *skb);
444
445/*
446 * Functions provided by ip_fragment.c
447 */
448
449enum ip_defrag_users {
450 IP_DEFRAG_LOCAL_DELIVER,
451 IP_DEFRAG_CALL_RA_CHAIN,
452 IP_DEFRAG_CONNTRACK_IN,
453 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
454 IP_DEFRAG_CONNTRACK_OUT,
455 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
456 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
457 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
458 IP_DEFRAG_VS_IN,
459 IP_DEFRAG_VS_OUT,
460 IP_DEFRAG_VS_FWD,
461 IP_DEFRAG_AF_PACKET,
462 IP_DEFRAG_MACVLAN,
463};
464
465int ip_defrag(struct sk_buff *skb, u32 user);
466#ifdef CONFIG_INET
467struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
468#else
469static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
470{
471 return skb;
472}
473#endif
474int ip_frag_mem(struct net *net);
475int ip_frag_nqueues(struct net *net);
476
477/*
478 * Functions provided by ip_forward.c
479 */
480
481int ip_forward(struct sk_buff *skb);
482
483/*
484 * Functions provided by ip_options.c
485 */
486
487void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
488 __be32 daddr, struct rtable *rt, int is_frag);
489int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
490void ip_options_fragment(struct sk_buff *skb);
491int ip_options_compile(struct net *net, struct ip_options *opt,
492 struct sk_buff *skb);
493int ip_options_get(struct net *net, struct ip_options_rcu **optp,
494 unsigned char *data, int optlen);
495int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
496 unsigned char __user *data, int optlen);
497void ip_options_undo(struct ip_options *opt);
498void ip_forward_options(struct sk_buff *skb);
499int ip_options_rcv_srr(struct sk_buff *skb);
500
501/*
502 * Functions provided by ip_sockglue.c
503 */
504
505void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
506void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
507int ip_cmsg_send(struct net *net, struct msghdr *msg,
508 struct ipcm_cookie *ipc, bool allow_ipv6);
509int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
510 unsigned int optlen);
511int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
512 int __user *optlen);
513int compat_ip_setsockopt(struct sock *sk, int level, int optname,
514 char __user *optval, unsigned int optlen);
515int compat_ip_getsockopt(struct sock *sk, int level, int optname,
516 char __user *optval, int __user *optlen);
517int ip_ra_control(struct sock *sk, unsigned char on,
518 void (*destructor)(struct sock *));
519
520int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
521void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
522 u32 info, u8 *payload);
523void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
524 u32 info);
525
526#ifdef CONFIG_PROC_FS
527int ip_misc_proc_init(void);
528#endif
529
530#endif /* _IP_H */