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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 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_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
191#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
192
193unsigned long snmp_fold_field(void __percpu *mib[], int offt);
194#if BITS_PER_LONG==32
195u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
196#else
197static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
198{
199 return snmp_fold_field(mib, offt);
200}
201#endif
202int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
203
204static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
205{
206 int i;
207
208 BUG_ON(ptr == NULL);
209 for (i = 0; i < SNMP_ARRAY_SZ; i++) {
210 free_percpu(ptr[i]);
211 ptr[i] = NULL;
212 }
213}
214
215void inet_get_local_port_range(struct net *net, int *low, int *high);
216
217extern unsigned long *sysctl_local_reserved_ports;
218static inline int inet_is_reserved_local_port(int port)
219{
220 return test_bit(port, sysctl_local_reserved_ports);
221}
222
223extern int sysctl_ip_nonlocal_bind;
224
225/* From inetpeer.c */
226extern int inet_peer_threshold;
227extern int inet_peer_minttl;
228extern int inet_peer_maxttl;
229
230/* From ip_input.c */
231extern int sysctl_ip_early_demux;
232
233/* From ip_output.c */
234extern int sysctl_ip_dynaddr;
235
236void ipfrag_init(void);
237
238void ip_static_sysctl_init(void);
239
240static inline bool ip_is_fragment(const struct iphdr *iph)
241{
242 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
243}
244
245#ifdef CONFIG_INET
246#include <net/dst.h>
247
248/* The function in 2.2 was invalid, producing wrong result for
249 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
250static inline
251int ip_decrease_ttl(struct iphdr *iph)
252{
253 u32 check = (__force u32)iph->check;
254 check += (__force u32)htons(0x0100);
255 iph->check = (__force __sum16)(check + (check>=0xFFFF));
256 return --iph->ttl;
257}
258
259static inline
260int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
261{
262 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
263 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
264 !(dst_metric_locked(dst, RTAX_MTU)));
265}
266
267static inline bool ip_sk_accept_pmtu(const struct sock *sk)
268{
269 return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE;
270}
271
272static inline bool ip_sk_use_pmtu(const struct sock *sk)
273{
274 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
275}
276
277static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
278 bool forwarding)
279{
280 struct net *net = dev_net(dst->dev);
281
282 if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
283 dst_metric_locked(dst, RTAX_MTU) ||
284 !forwarding)
285 return dst_mtu(dst);
286
287 return min(dst->dev->mtu, IP_MAX_MTU);
288}
289
290static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb)
291{
292 if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
293 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
294 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
295 } else {
296 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
297 }
298}
299
300void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
301
302static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
303{
304 struct iphdr *iph = ip_hdr(skb);
305
306 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
307 /* This is only to work around buggy Windows95/2000
308 * VJ compression implementations. If the ID field
309 * does not change, they drop every other packet in
310 * a TCP stream using header compression.
311 */
312 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
313 htons(inet_sk(sk)->inet_id++) : 0;
314 } else
315 __ip_select_ident(iph, dst, 0);
316}
317
318static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
319{
320 struct iphdr *iph = ip_hdr(skb);
321
322 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
323 if (sk && inet_sk(sk)->inet_daddr) {
324 iph->id = htons(inet_sk(sk)->inet_id);
325 inet_sk(sk)->inet_id += 1 + more;
326 } else
327 iph->id = 0;
328 } else
329 __ip_select_ident(iph, dst, more);
330}
331
332/*
333 * Map a multicast IP onto multicast MAC for type ethernet.
334 */
335
336static inline void ip_eth_mc_map(__be32 naddr, char *buf)
337{
338 __u32 addr=ntohl(naddr);
339 buf[0]=0x01;
340 buf[1]=0x00;
341 buf[2]=0x5e;
342 buf[5]=addr&0xFF;
343 addr>>=8;
344 buf[4]=addr&0xFF;
345 addr>>=8;
346 buf[3]=addr&0x7F;
347}
348
349/*
350 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
351 * Leave P_Key as 0 to be filled in by driver.
352 */
353
354static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
355{
356 __u32 addr;
357 unsigned char scope = broadcast[5] & 0xF;
358
359 buf[0] = 0; /* Reserved */
360 buf[1] = 0xff; /* Multicast QPN */
361 buf[2] = 0xff;
362 buf[3] = 0xff;
363 addr = ntohl(naddr);
364 buf[4] = 0xff;
365 buf[5] = 0x10 | scope; /* scope from broadcast address */
366 buf[6] = 0x40; /* IPv4 signature */
367 buf[7] = 0x1b;
368 buf[8] = broadcast[8]; /* P_Key */
369 buf[9] = broadcast[9];
370 buf[10] = 0;
371 buf[11] = 0;
372 buf[12] = 0;
373 buf[13] = 0;
374 buf[14] = 0;
375 buf[15] = 0;
376 buf[19] = addr & 0xff;
377 addr >>= 8;
378 buf[18] = addr & 0xff;
379 addr >>= 8;
380 buf[17] = addr & 0xff;
381 addr >>= 8;
382 buf[16] = addr & 0x0f;
383}
384
385static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
386{
387 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
388 memcpy(buf, broadcast, 4);
389 else
390 memcpy(buf, &naddr, sizeof(naddr));
391}
392
393#if IS_ENABLED(CONFIG_IPV6)
394#include <linux/ipv6.h>
395#endif
396
397static __inline__ void inet_reset_saddr(struct sock *sk)
398{
399 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
400#if IS_ENABLED(CONFIG_IPV6)
401 if (sk->sk_family == PF_INET6) {
402 struct ipv6_pinfo *np = inet6_sk(sk);
403
404 memset(&np->saddr, 0, sizeof(np->saddr));
405 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
406 }
407#endif
408}
409
410#endif
411
412static inline int sk_mc_loop(struct sock *sk)
413{
414 if (!sk)
415 return 1;
416 switch (sk->sk_family) {
417 case AF_INET:
418 return inet_sk(sk)->mc_loop;
419#if IS_ENABLED(CONFIG_IPV6)
420 case AF_INET6:
421 return inet6_sk(sk)->mc_loop;
422#endif
423 }
424 WARN_ON(1);
425 return 1;
426}
427
428bool ip_call_ra_chain(struct sk_buff *skb);
429
430/*
431 * Functions provided by ip_fragment.c
432 */
433
434enum ip_defrag_users {
435 IP_DEFRAG_LOCAL_DELIVER,
436 IP_DEFRAG_CALL_RA_CHAIN,
437 IP_DEFRAG_CONNTRACK_IN,
438 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
439 IP_DEFRAG_CONNTRACK_OUT,
440 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
441 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
442 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
443 IP_DEFRAG_VS_IN,
444 IP_DEFRAG_VS_OUT,
445 IP_DEFRAG_VS_FWD,
446 IP_DEFRAG_AF_PACKET,
447 IP_DEFRAG_MACVLAN,
448};
449
450int ip_defrag(struct sk_buff *skb, u32 user);
451#ifdef CONFIG_INET
452struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
453#else
454static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
455{
456 return skb;
457}
458#endif
459int ip_frag_mem(struct net *net);
460int ip_frag_nqueues(struct net *net);
461
462/*
463 * Functions provided by ip_forward.c
464 */
465
466int ip_forward(struct sk_buff *skb);
467
468/*
469 * Functions provided by ip_options.c
470 */
471
472void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
473 __be32 daddr, struct rtable *rt, int is_frag);
474int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
475void ip_options_fragment(struct sk_buff *skb);
476int ip_options_compile(struct net *net, struct ip_options *opt,
477 struct sk_buff *skb);
478int ip_options_get(struct net *net, struct ip_options_rcu **optp,
479 unsigned char *data, int optlen);
480int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
481 unsigned char __user *data, int optlen);
482void ip_options_undo(struct ip_options *opt);
483void ip_forward_options(struct sk_buff *skb);
484int ip_options_rcv_srr(struct sk_buff *skb);
485
486/*
487 * Functions provided by ip_sockglue.c
488 */
489
490void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
491void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
492int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc);
493int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
494 unsigned int optlen);
495int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
496 int __user *optlen);
497int compat_ip_setsockopt(struct sock *sk, int level, int optname,
498 char __user *optval, unsigned int optlen);
499int compat_ip_getsockopt(struct sock *sk, int level, int optname,
500 char __user *optval, int __user *optlen);
501int ip_ra_control(struct sock *sk, unsigned char on,
502 void (*destructor)(struct sock *));
503
504int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
505void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
506 u32 info, u8 *payload);
507void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
508 u32 info);
509
510#ifdef CONFIG_PROC_FS
511int ip_misc_proc_init(void);
512#endif
513
514#endif /* _IP_H */