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/snmp.h>
32 #include <net/flow.h>
33
34 struct sock;
35
36 struct inet_skb_parm {
37 struct ip_options opt; /* Compiled IP options */
38 unsigned char flags;
39
40 #define IPSKB_FORWARDED BIT(0)
41 #define IPSKB_XFRM_TUNNEL_SIZE BIT(1)
42 #define IPSKB_XFRM_TRANSFORMED BIT(2)
43 #define IPSKB_FRAG_COMPLETE BIT(3)
44 #define IPSKB_REROUTED BIT(4)
45 #define IPSKB_DOREDIRECT BIT(5)
46
47 u16 frag_max_size;
48 };
49
ip_hdrlen(const struct sk_buff * skb)50 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
51 {
52 return ip_hdr(skb)->ihl * 4;
53 }
54
55 struct ipcm_cookie {
56 __be32 addr;
57 int oif;
58 struct ip_options_rcu *opt;
59 __u8 tx_flags;
60 };
61
62 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
63
64 struct ip_ra_chain {
65 struct ip_ra_chain __rcu *next;
66 struct sock *sk;
67 union {
68 void (*destructor)(struct sock *);
69 struct sock *saved_sk;
70 };
71 struct rcu_head rcu;
72 };
73
74 extern struct ip_ra_chain __rcu *ip_ra_chain;
75
76 /* IP flags. */
77 #define IP_CE 0x8000 /* Flag: "Congestion" */
78 #define IP_DF 0x4000 /* Flag: "Don't Fragment" */
79 #define IP_MF 0x2000 /* Flag: "More Fragments" */
80 #define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
81
82 #define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
83
84 struct msghdr;
85 struct net_device;
86 struct packet_type;
87 struct rtable;
88 struct sockaddr;
89
90 extern int igmp_mc_proc_init(void);
91
92 /*
93 * Functions provided by ip.c
94 */
95
96 extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
97 __be32 saddr, __be32 daddr,
98 struct ip_options_rcu *opt);
99 extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
100 struct packet_type *pt, struct net_device *orig_dev);
101 extern int ip_local_deliver(struct sk_buff *skb);
102 extern int ip_mr_input(struct sk_buff *skb);
103 extern int ip_output(struct sk_buff *skb);
104 extern int ip_mc_output(struct sk_buff *skb);
105 extern int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
106 extern int ip_do_nat(struct sk_buff *skb);
107 extern void ip_send_check(struct iphdr *ip);
108 extern int __ip_local_out(struct sk_buff *skb);
109 extern int ip_local_out(struct sk_buff *skb);
110 extern int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
111 extern void ip_init(void);
112 extern int ip_append_data(struct sock *sk, struct flowi4 *fl4,
113 int getfrag(void *from, char *to, int offset, int len,
114 int odd, struct sk_buff *skb),
115 void *from, int len, int protolen,
116 struct ipcm_cookie *ipc,
117 struct rtable **rt,
118 unsigned int flags);
119 extern int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
120 extern ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
121 int offset, size_t size, int flags);
122 extern struct sk_buff *__ip_make_skb(struct sock *sk,
123 struct flowi4 *fl4,
124 struct sk_buff_head *queue,
125 struct inet_cork *cork);
126 extern int ip_send_skb(struct net *net, struct sk_buff *skb);
127 extern int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
128 extern void ip_flush_pending_frames(struct sock *sk);
129 extern struct sk_buff *ip_make_skb(struct sock *sk,
130 struct flowi4 *fl4,
131 int getfrag(void *from, char *to, int offset, int len,
132 int odd, struct sk_buff *skb),
133 void *from, int length, int transhdrlen,
134 struct ipcm_cookie *ipc,
135 struct rtable **rtp,
136 unsigned int flags);
137
ip_finish_skb(struct sock * sk,struct flowi4 * fl4)138 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
139 {
140 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
141 }
142
143 /* datagram.c */
144 extern int ip4_datagram_connect(struct sock *sk,
145 struct sockaddr *uaddr, int addr_len);
146
147 extern void ip4_datagram_release_cb(struct sock *sk);
148
149 struct ip_reply_arg {
150 struct kvec iov[1];
151 int flags;
152 __wsum csum;
153 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
154 /* -1 if not needed */
155 int bound_dev_if;
156 u8 tos;
157 kuid_t uid;
158 };
159
160 #define IP_REPLY_ARG_NOSRCCHECK 1
161
ip_reply_arg_flowi_flags(const struct ip_reply_arg * arg)162 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
163 {
164 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
165 }
166
167 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, __be32 daddr,
168 __be32 saddr, const struct ip_reply_arg *arg,
169 unsigned int len);
170
171 struct ipv4_config {
172 int log_martians;
173 int no_pmtu_disc;
174 };
175
176 extern struct ipv4_config ipv4_config;
177 #define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
178 #define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
179 #define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
180 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
181 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
182 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
183 #define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
184 #define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
185 #define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
186 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
187 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
188
189 extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
190 #if BITS_PER_LONG==32
191 extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
192 #else
snmp_fold_field64(void __percpu * mib[],int offt,size_t syncp_off)193 static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
194 {
195 return snmp_fold_field(mib, offt);
196 }
197 #endif
198 extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
199 extern void snmp_mib_free(void __percpu *ptr[2]);
200
201 extern struct local_ports {
202 seqlock_t lock;
203 int range[2];
204 } sysctl_local_ports;
205 extern void inet_get_local_port_range(int *low, int *high);
206
207 extern unsigned long *sysctl_local_reserved_ports;
inet_is_reserved_local_port(int port)208 static inline int inet_is_reserved_local_port(int port)
209 {
210 return test_bit(port, sysctl_local_reserved_ports);
211 }
212
213 extern int sysctl_ip_nonlocal_bind;
214
215 /* From inetpeer.c */
216 extern int inet_peer_threshold;
217 extern int inet_peer_minttl;
218 extern int inet_peer_maxttl;
219
220 /* From ip_input.c */
221 extern int sysctl_ip_early_demux;
222
223 /* From ip_output.c */
224 extern int sysctl_ip_dynaddr;
225
226 extern void ipfrag_init(void);
227
228 extern void ip_static_sysctl_init(void);
229
230 #define IP4_REPLY_MARK(net, mark) \
231 ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
232
ip_is_fragment(const struct iphdr * iph)233 static inline bool ip_is_fragment(const struct iphdr *iph)
234 {
235 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
236 }
237
238 #ifdef CONFIG_INET
239 #include <net/dst.h>
240
241 /* The function in 2.2 was invalid, producing wrong result for
242 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
243 static inline
ip_decrease_ttl(struct iphdr * iph)244 int ip_decrease_ttl(struct iphdr *iph)
245 {
246 u32 check = (__force u32)iph->check;
247 check += (__force u32)htons(0x0100);
248 iph->check = (__force __sum16)(check + (check>=0xFFFF));
249 return --iph->ttl;
250 }
251
252 static inline
ip_dont_fragment(struct sock * sk,struct dst_entry * dst)253 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
254 {
255 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
256 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
257 !(dst_metric_locked(dst, RTAX_MTU)));
258 }
259
260 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
261
ip_select_ident(struct iphdr * iph,struct dst_entry * dst,struct sock * sk)262 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
263 {
264 if (iph->frag_off & htons(IP_DF)) {
265 /* This is only to work around buggy Windows95/2000
266 * VJ compression implementations. If the ID field
267 * does not change, they drop every other packet in
268 * a TCP stream using header compression.
269 */
270 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
271 htons(inet_sk(sk)->inet_id++) : 0;
272 } else
273 __ip_select_ident(iph, dst, 0);
274 }
275
ip_select_ident_more(struct iphdr * iph,struct dst_entry * dst,struct sock * sk,int more)276 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
277 {
278 if (iph->frag_off & htons(IP_DF)) {
279 if (sk && inet_sk(sk)->inet_daddr) {
280 iph->id = htons(inet_sk(sk)->inet_id);
281 inet_sk(sk)->inet_id += 1 + more;
282 } else
283 iph->id = 0;
284 } else
285 __ip_select_ident(iph, dst, more);
286 }
287
288 /*
289 * Map a multicast IP onto multicast MAC for type ethernet.
290 */
291
ip_eth_mc_map(__be32 naddr,char * buf)292 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
293 {
294 __u32 addr=ntohl(naddr);
295 buf[0]=0x01;
296 buf[1]=0x00;
297 buf[2]=0x5e;
298 buf[5]=addr&0xFF;
299 addr>>=8;
300 buf[4]=addr&0xFF;
301 addr>>=8;
302 buf[3]=addr&0x7F;
303 }
304
305 /*
306 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
307 * Leave P_Key as 0 to be filled in by driver.
308 */
309
ip_ib_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)310 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
311 {
312 __u32 addr;
313 unsigned char scope = broadcast[5] & 0xF;
314
315 buf[0] = 0; /* Reserved */
316 buf[1] = 0xff; /* Multicast QPN */
317 buf[2] = 0xff;
318 buf[3] = 0xff;
319 addr = ntohl(naddr);
320 buf[4] = 0xff;
321 buf[5] = 0x10 | scope; /* scope from broadcast address */
322 buf[6] = 0x40; /* IPv4 signature */
323 buf[7] = 0x1b;
324 buf[8] = broadcast[8]; /* P_Key */
325 buf[9] = broadcast[9];
326 buf[10] = 0;
327 buf[11] = 0;
328 buf[12] = 0;
329 buf[13] = 0;
330 buf[14] = 0;
331 buf[15] = 0;
332 buf[19] = addr & 0xff;
333 addr >>= 8;
334 buf[18] = addr & 0xff;
335 addr >>= 8;
336 buf[17] = addr & 0xff;
337 addr >>= 8;
338 buf[16] = addr & 0x0f;
339 }
340
ip_ipgre_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)341 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
342 {
343 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
344 memcpy(buf, broadcast, 4);
345 else
346 memcpy(buf, &naddr, sizeof(naddr));
347 }
348
349 #if IS_ENABLED(CONFIG_IPV6)
350 #include <linux/ipv6.h>
351 #endif
352
inet_reset_saddr(struct sock * sk)353 static __inline__ void inet_reset_saddr(struct sock *sk)
354 {
355 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
356 #if IS_ENABLED(CONFIG_IPV6)
357 if (sk->sk_family == PF_INET6) {
358 struct ipv6_pinfo *np = inet6_sk(sk);
359
360 memset(&np->saddr, 0, sizeof(np->saddr));
361 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
362 }
363 #endif
364 }
365
366 #endif
367
sk_mc_loop(struct sock * sk)368 static inline int sk_mc_loop(struct sock *sk)
369 {
370 if (!sk)
371 return 1;
372 switch (sk->sk_family) {
373 case AF_INET:
374 return inet_sk(sk)->mc_loop;
375 #if IS_ENABLED(CONFIG_IPV6)
376 case AF_INET6:
377 return inet6_sk(sk)->mc_loop;
378 #endif
379 }
380 WARN_ON(1);
381 return 1;
382 }
383
384 extern bool ip_call_ra_chain(struct sk_buff *skb);
385
386 /*
387 * Functions provided by ip_fragment.c
388 */
389
390 enum ip_defrag_users {
391 IP_DEFRAG_LOCAL_DELIVER,
392 IP_DEFRAG_CALL_RA_CHAIN,
393 IP_DEFRAG_CONNTRACK_IN,
394 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
395 IP_DEFRAG_CONNTRACK_OUT,
396 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
397 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
398 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
399 IP_DEFRAG_VS_IN,
400 IP_DEFRAG_VS_OUT,
401 IP_DEFRAG_VS_FWD,
402 IP_DEFRAG_AF_PACKET,
403 IP_DEFRAG_MACVLAN,
404 };
405
406 int ip_defrag(struct sk_buff *skb, u32 user);
407 #ifdef CONFIG_INET
408 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
409 #else
ip_check_defrag(struct sk_buff * skb,u32 user)410 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
411 {
412 return skb;
413 }
414 #endif
415 int ip_frag_mem(struct net *net);
416 int ip_frag_nqueues(struct net *net);
417
418 /*
419 * Functions provided by ip_forward.c
420 */
421
422 extern int ip_forward(struct sk_buff *skb);
423
424 /*
425 * Functions provided by ip_options.c
426 */
427
428 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
429 __be32 daddr, struct rtable *rt, int is_frag);
430 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
431 extern void ip_options_fragment(struct sk_buff *skb);
432 extern int ip_options_compile(struct net *net,
433 struct ip_options *opt, struct sk_buff *skb);
434 extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
435 unsigned char *data, int optlen);
436 extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
437 unsigned char __user *data, int optlen);
438 extern void ip_options_undo(struct ip_options * opt);
439 extern void ip_forward_options(struct sk_buff *skb);
440 extern int ip_options_rcv_srr(struct sk_buff *skb);
441
442 /*
443 * Functions provided by ip_sockglue.c
444 */
445
446 extern void ipv4_pktinfo_prepare(struct sk_buff *skb);
447 extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
448 extern int ip_cmsg_send(struct net *net,
449 struct msghdr *msg, struct ipcm_cookie *ipc);
450 extern int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
451 extern int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
452 extern int compat_ip_setsockopt(struct sock *sk, int level,
453 int optname, char __user *optval, unsigned int optlen);
454 extern int compat_ip_getsockopt(struct sock *sk, int level,
455 int optname, char __user *optval, int __user *optlen);
456 extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
457
458 extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
459 extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
460 __be16 port, u32 info, u8 *payload);
461 extern void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
462 u32 info);
463
464 #ifdef CONFIG_PROC_FS
465 extern int ip_misc_proc_init(void);
466 #endif
467
468 #endif /* _IP_H */
469