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 1
41 #define IPSKB_XFRM_TUNNEL_SIZE 2
42 #define IPSKB_XFRM_TRANSFORMED 4
43 #define IPSKB_FRAG_COMPLETE 8
44 #define IPSKB_REROUTED 16
45 };
46
ip_hdrlen(const struct sk_buff * skb)47 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
48 {
49 return ip_hdr(skb)->ihl * 4;
50 }
51
52 struct ipcm_cookie {
53 __be32 addr;
54 int oif;
55 struct ip_options_rcu *opt;
56 __u8 tx_flags;
57 };
58
59 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
60
61 struct ip_ra_chain {
62 struct ip_ra_chain __rcu *next;
63 struct sock *sk;
64 union {
65 void (*destructor)(struct sock *);
66 struct sock *saved_sk;
67 };
68 struct rcu_head rcu;
69 };
70
71 extern struct ip_ra_chain __rcu *ip_ra_chain;
72
73 /* IP flags. */
74 #define IP_CE 0x8000 /* Flag: "Congestion" */
75 #define IP_DF 0x4000 /* Flag: "Don't Fragment" */
76 #define IP_MF 0x2000 /* Flag: "More Fragments" */
77 #define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
78
79 #define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
80
81 struct msghdr;
82 struct net_device;
83 struct packet_type;
84 struct rtable;
85 struct sockaddr;
86
87 extern int igmp_mc_proc_init(void);
88
89 /*
90 * Functions provided by ip.c
91 */
92
93 extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
94 __be32 saddr, __be32 daddr,
95 struct ip_options_rcu *opt);
96 extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
97 struct packet_type *pt, struct net_device *orig_dev);
98 extern int ip_local_deliver(struct sk_buff *skb);
99 extern int ip_mr_input(struct sk_buff *skb);
100 extern int ip_output(struct sk_buff *skb);
101 extern int ip_mc_output(struct sk_buff *skb);
102 extern int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
103 extern int ip_do_nat(struct sk_buff *skb);
104 extern void ip_send_check(struct iphdr *ip);
105 extern int __ip_local_out(struct sk_buff *skb);
106 extern int ip_local_out(struct sk_buff *skb);
107 extern int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
108 extern void ip_init(void);
109 extern int ip_append_data(struct sock *sk, struct flowi4 *fl4,
110 int getfrag(void *from, char *to, int offset, int len,
111 int odd, struct sk_buff *skb),
112 void *from, int len, int protolen,
113 struct ipcm_cookie *ipc,
114 struct rtable **rt,
115 unsigned int flags);
116 extern int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
117 extern ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
118 int offset, size_t size, int flags);
119 extern struct sk_buff *__ip_make_skb(struct sock *sk,
120 struct flowi4 *fl4,
121 struct sk_buff_head *queue,
122 struct inet_cork *cork);
123 extern int ip_send_skb(struct sk_buff *skb);
124 extern int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
125 extern void ip_flush_pending_frames(struct sock *sk);
126 extern struct sk_buff *ip_make_skb(struct sock *sk,
127 struct flowi4 *fl4,
128 int getfrag(void *from, char *to, int offset, int len,
129 int odd, struct sk_buff *skb),
130 void *from, int length, int transhdrlen,
131 struct ipcm_cookie *ipc,
132 struct rtable **rtp,
133 unsigned int flags);
134
ip_finish_skb(struct sock * sk,struct flowi4 * fl4)135 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
136 {
137 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
138 }
139
140 /* datagram.c */
141 extern int ip4_datagram_connect(struct sock *sk,
142 struct sockaddr *uaddr, int addr_len);
143
144 /*
145 * Map a multicast IP onto multicast MAC for type Token Ring.
146 * This conforms to RFC1469 Option 2 Multicasting i.e.
147 * using a functional address to transmit / receive
148 * multicast packets.
149 */
150
ip_tr_mc_map(__be32 addr,char * buf)151 static inline void ip_tr_mc_map(__be32 addr, char *buf)
152 {
153 buf[0]=0xC0;
154 buf[1]=0x00;
155 buf[2]=0x00;
156 buf[3]=0x04;
157 buf[4]=0x00;
158 buf[5]=0x00;
159 }
160
161 struct ip_reply_arg {
162 struct kvec iov[1];
163 int flags;
164 __wsum csum;
165 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
166 /* -1 if not needed */
167 int bound_dev_if;
168 u8 tos;
169 };
170
171 #define IP_REPLY_ARG_NOSRCCHECK 1
172
ip_reply_arg_flowi_flags(const struct ip_reply_arg * arg)173 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
174 {
175 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
176 }
177
178 void ip_send_reply(struct sock *sk, struct sk_buff *skb, __be32 daddr,
179 const struct ip_reply_arg *arg, unsigned int len);
180
181 struct ipv4_config {
182 int log_martians;
183 int no_pmtu_disc;
184 };
185
186 extern struct ipv4_config ipv4_config;
187 #define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
188 #define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
189 #define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
190 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
191 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
192 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
193 #define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
194 #define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
195 #define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
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
199 extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
200 #if BITS_PER_LONG==32
201 extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
202 #else
snmp_fold_field64(void __percpu * mib[],int offt,size_t syncp_off)203 static 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 extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
209 extern void snmp_mib_free(void __percpu *ptr[2]);
210
211 extern struct local_ports {
212 seqlock_t lock;
213 int range[2];
214 } sysctl_local_ports;
215 extern void inet_get_local_port_range(int *low, int *high);
216
217 extern unsigned long *sysctl_local_reserved_ports;
inet_is_reserved_local_port(int port)218 static inline int inet_is_reserved_local_port(int port)
219 {
220 return test_bit(port, sysctl_local_reserved_ports);
221 }
222
223 extern int sysctl_ip_nonlocal_bind;
224
225 extern struct ctl_path net_core_path[];
226 extern struct ctl_path net_ipv4_ctl_path[];
227
228 /* From inetpeer.c */
229 extern int inet_peer_threshold;
230 extern int inet_peer_minttl;
231 extern int inet_peer_maxttl;
232
233 /* From ip_output.c */
234 extern int sysctl_ip_dynaddr;
235
236 extern void ipfrag_init(void);
237
238 extern void ip_static_sysctl_init(void);
239
ip_is_fragment(const struct iphdr * iph)240 static 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) */
250 static inline
ip_decrease_ttl(struct iphdr * iph)251 int 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
259 static inline
ip_dont_fragment(struct sock * sk,struct dst_entry * dst)260 int 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
267 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
268
ip_select_ident(struct sk_buff * skb,struct dst_entry * dst,struct sock * sk)269 static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
270 {
271 struct iphdr *iph = ip_hdr(skb);
272
273 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
274 /* This is only to work around buggy Windows95/2000
275 * VJ compression implementations. If the ID field
276 * does not change, they drop every other packet in
277 * a TCP stream using header compression.
278 */
279 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
280 htons(inet_sk(sk)->inet_id++) : 0;
281 } else
282 __ip_select_ident(iph, dst, 0);
283 }
284
ip_select_ident_more(struct sk_buff * skb,struct dst_entry * dst,struct sock * sk,int more)285 static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
286 {
287 struct iphdr *iph = ip_hdr(skb);
288
289 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
290 if (sk && inet_sk(sk)->inet_daddr) {
291 iph->id = htons(inet_sk(sk)->inet_id);
292 inet_sk(sk)->inet_id += 1 + more;
293 } else
294 iph->id = 0;
295 } else
296 __ip_select_ident(iph, dst, more);
297 }
298
299 /*
300 * Map a multicast IP onto multicast MAC for type ethernet.
301 */
302
ip_eth_mc_map(__be32 naddr,char * buf)303 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
304 {
305 __u32 addr=ntohl(naddr);
306 buf[0]=0x01;
307 buf[1]=0x00;
308 buf[2]=0x5e;
309 buf[5]=addr&0xFF;
310 addr>>=8;
311 buf[4]=addr&0xFF;
312 addr>>=8;
313 buf[3]=addr&0x7F;
314 }
315
316 /*
317 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
318 * Leave P_Key as 0 to be filled in by driver.
319 */
320
ip_ib_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)321 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
322 {
323 __u32 addr;
324 unsigned char scope = broadcast[5] & 0xF;
325
326 buf[0] = 0; /* Reserved */
327 buf[1] = 0xff; /* Multicast QPN */
328 buf[2] = 0xff;
329 buf[3] = 0xff;
330 addr = ntohl(naddr);
331 buf[4] = 0xff;
332 buf[5] = 0x10 | scope; /* scope from broadcast address */
333 buf[6] = 0x40; /* IPv4 signature */
334 buf[7] = 0x1b;
335 buf[8] = broadcast[8]; /* P_Key */
336 buf[9] = broadcast[9];
337 buf[10] = 0;
338 buf[11] = 0;
339 buf[12] = 0;
340 buf[13] = 0;
341 buf[14] = 0;
342 buf[15] = 0;
343 buf[19] = addr & 0xff;
344 addr >>= 8;
345 buf[18] = addr & 0xff;
346 addr >>= 8;
347 buf[17] = addr & 0xff;
348 addr >>= 8;
349 buf[16] = addr & 0x0f;
350 }
351
ip_ipgre_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)352 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
353 {
354 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
355 memcpy(buf, broadcast, 4);
356 else
357 memcpy(buf, &naddr, sizeof(naddr));
358 }
359
360 #if IS_ENABLED(CONFIG_IPV6)
361 #include <linux/ipv6.h>
362 #endif
363
inet_reset_saddr(struct sock * sk)364 static __inline__ void inet_reset_saddr(struct sock *sk)
365 {
366 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
367 #if IS_ENABLED(CONFIG_IPV6)
368 if (sk->sk_family == PF_INET6) {
369 struct ipv6_pinfo *np = inet6_sk(sk);
370
371 memset(&np->saddr, 0, sizeof(np->saddr));
372 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
373 }
374 #endif
375 }
376
377 #endif
378
sk_mc_loop(struct sock * sk)379 static inline int sk_mc_loop(struct sock *sk)
380 {
381 if (!sk)
382 return 1;
383 switch (sk->sk_family) {
384 case AF_INET:
385 return inet_sk(sk)->mc_loop;
386 #if IS_ENABLED(CONFIG_IPV6)
387 case AF_INET6:
388 return inet6_sk(sk)->mc_loop;
389 #endif
390 }
391 WARN_ON(1);
392 return 1;
393 }
394
395 extern bool ip_call_ra_chain(struct sk_buff *skb);
396
397 /*
398 * Functions provided by ip_fragment.c
399 */
400
401 enum ip_defrag_users {
402 IP_DEFRAG_LOCAL_DELIVER,
403 IP_DEFRAG_CALL_RA_CHAIN,
404 IP_DEFRAG_CONNTRACK_IN,
405 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
406 IP_DEFRAG_CONNTRACK_OUT,
407 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
408 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
409 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
410 IP_DEFRAG_VS_IN,
411 IP_DEFRAG_VS_OUT,
412 IP_DEFRAG_VS_FWD,
413 IP_DEFRAG_AF_PACKET,
414 IP_DEFRAG_MACVLAN,
415 };
416
417 int ip_defrag(struct sk_buff *skb, u32 user);
418 #ifdef CONFIG_INET
419 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
420 #else
ip_check_defrag(struct sk_buff * skb,u32 user)421 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
422 {
423 return skb;
424 }
425 #endif
426 int ip_frag_mem(struct net *net);
427 int ip_frag_nqueues(struct net *net);
428
429 /*
430 * Functions provided by ip_forward.c
431 */
432
433 extern int ip_forward(struct sk_buff *skb);
434
435 /*
436 * Functions provided by ip_options.c
437 */
438
439 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
440 __be32 daddr, struct rtable *rt, int is_frag);
441 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
442 extern void ip_options_fragment(struct sk_buff *skb);
443 extern int ip_options_compile(struct net *net,
444 struct ip_options *opt, struct sk_buff *skb);
445 extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
446 unsigned char *data, int optlen);
447 extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
448 unsigned char __user *data, int optlen);
449 extern void ip_options_undo(struct ip_options * opt);
450 extern void ip_forward_options(struct sk_buff *skb);
451 extern int ip_options_rcv_srr(struct sk_buff *skb);
452
453 /*
454 * Functions provided by ip_sockglue.c
455 */
456
457 extern void ipv4_pktinfo_prepare(struct sk_buff *skb);
458 extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
459 extern int ip_cmsg_send(struct net *net,
460 struct msghdr *msg, struct ipcm_cookie *ipc);
461 extern int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
462 extern int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
463 extern int compat_ip_setsockopt(struct sock *sk, int level,
464 int optname, char __user *optval, unsigned int optlen);
465 extern int compat_ip_getsockopt(struct sock *sk, int level,
466 int optname, char __user *optval, int __user *optlen);
467 extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
468
469 extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
470 extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
471 __be16 port, u32 info, u8 *payload);
472 extern void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
473 u32 info);
474
475 #ifdef CONFIG_PROC_FS
476 extern int ip_misc_proc_init(void);
477 #endif
478
479 #endif /* _IP_H */
480