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