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
ip_hdrlen(const struct sk_buff * skb)48 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
49 {
50 return ip_hdr(skb)->ihl * 4;
51 }
52
53 struct ipcm_cookie {
54 __be32 addr;
55 int oif;
56 struct ip_options_rcu *opt;
57 __u8 tx_flags;
58 };
59
60 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
61
62 struct ip_ra_chain {
63 struct ip_ra_chain __rcu *next;
64 struct sock *sk;
65 union {
66 void (*destructor)(struct sock *);
67 struct sock *saved_sk;
68 };
69 struct rcu_head rcu;
70 };
71
72 extern struct ip_ra_chain __rcu *ip_ra_chain;
73
74 /* IP flags. */
75 #define IP_CE 0x8000 /* Flag: "Congestion" */
76 #define IP_DF 0x4000 /* Flag: "Don't Fragment" */
77 #define IP_MF 0x2000 /* Flag: "More Fragments" */
78 #define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
79
80 #define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
81
82 struct msghdr;
83 struct net_device;
84 struct packet_type;
85 struct rtable;
86 struct sockaddr;
87
88 extern int igmp_mc_proc_init(void);
89
90 /*
91 * Functions provided by ip.c
92 */
93
94 extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
95 __be32 saddr, __be32 daddr,
96 struct ip_options_rcu *opt);
97 extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
98 struct packet_type *pt, struct net_device *orig_dev);
99 extern int ip_local_deliver(struct sk_buff *skb);
100 extern int ip_mr_input(struct sk_buff *skb);
101 extern int ip_output(struct sk_buff *skb);
102 extern int ip_mc_output(struct sk_buff *skb);
103 extern int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
104 extern int ip_do_nat(struct sk_buff *skb);
105 extern void ip_send_check(struct iphdr *ip);
106 extern int __ip_local_out(struct sk_buff *skb);
107 extern int ip_local_out(struct sk_buff *skb);
108 extern int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
109 extern void ip_init(void);
110 extern int ip_append_data(struct sock *sk, struct flowi4 *fl4,
111 int getfrag(void *from, char *to, int offset, int len,
112 int odd, struct sk_buff *skb),
113 void *from, int len, int protolen,
114 struct ipcm_cookie *ipc,
115 struct rtable **rt,
116 unsigned int flags);
117 extern int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
118 extern ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
119 int offset, size_t size, int flags);
120 extern struct sk_buff *__ip_make_skb(struct sock *sk,
121 struct flowi4 *fl4,
122 struct sk_buff_head *queue,
123 struct inet_cork *cork);
124 extern int ip_send_skb(struct sk_buff *skb);
125 extern int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
126 extern void ip_flush_pending_frames(struct sock *sk);
127 extern struct sk_buff *ip_make_skb(struct sock *sk,
128 struct flowi4 *fl4,
129 int getfrag(void *from, char *to, int offset, int len,
130 int odd, struct sk_buff *skb),
131 void *from, int length, int transhdrlen,
132 struct ipcm_cookie *ipc,
133 struct rtable **rtp,
134 unsigned int flags);
135
ip_finish_skb(struct sock * sk,struct flowi4 * fl4)136 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
137 {
138 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
139 }
140
141 /* datagram.c */
142 extern int ip4_datagram_connect(struct sock *sk,
143 struct sockaddr *uaddr, int addr_len);
144
145 /*
146 * Map a multicast IP onto multicast MAC for type Token Ring.
147 * This conforms to RFC1469 Option 2 Multicasting i.e.
148 * using a functional address to transmit / receive
149 * multicast packets.
150 */
151
ip_tr_mc_map(__be32 addr,char * buf)152 static inline void ip_tr_mc_map(__be32 addr, char *buf)
153 {
154 buf[0]=0xC0;
155 buf[1]=0x00;
156 buf[2]=0x00;
157 buf[3]=0x04;
158 buf[4]=0x00;
159 buf[5]=0x00;
160 }
161
162 struct ip_reply_arg {
163 struct kvec iov[1];
164 int flags;
165 __wsum csum;
166 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
167 /* -1 if not needed */
168 int bound_dev_if;
169 u8 tos;
170 uid_t uid;
171 };
172
173 #define IP_REPLY_ARG_NOSRCCHECK 1
174
ip_reply_arg_flowi_flags(const struct ip_reply_arg * arg)175 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
176 {
177 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
178 }
179
180 void ip_send_reply(struct sock *sk, struct sk_buff *skb, __be32 daddr,
181 const struct ip_reply_arg *arg, unsigned int len);
182
183 struct ipv4_config {
184 int log_martians;
185 int no_pmtu_disc;
186 };
187
188 extern struct ipv4_config ipv4_config;
189 #define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
190 #define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
191 #define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
192 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
193 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
194 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
195 #define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
196 #define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
197 #define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
198 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
199 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
200
201 extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
202 #if BITS_PER_LONG==32
203 extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
204 #else
snmp_fold_field64(void __percpu * mib[],int offt,size_t syncp_off)205 static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
206 {
207 return snmp_fold_field(mib, offt);
208 }
209 #endif
210 extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
211 extern void snmp_mib_free(void __percpu *ptr[2]);
212
213 extern struct local_ports {
214 seqlock_t lock;
215 int range[2];
216 } sysctl_local_ports;
217 extern void inet_get_local_port_range(int *low, int *high);
218
219 extern unsigned long *sysctl_local_reserved_ports;
inet_is_reserved_local_port(int port)220 static inline int inet_is_reserved_local_port(int port)
221 {
222 return test_bit(port, sysctl_local_reserved_ports);
223 }
224
225 extern int sysctl_ip_nonlocal_bind;
226
227 extern struct ctl_path net_core_path[];
228 extern struct ctl_path net_ipv4_ctl_path[];
229
230 /* From inetpeer.c */
231 extern int inet_peer_threshold;
232 extern int inet_peer_minttl;
233 extern int inet_peer_maxttl;
234
235 /* From ip_output.c */
236 extern int sysctl_ip_dynaddr;
237
238 extern void ipfrag_init(void);
239
240 extern void ip_static_sysctl_init(void);
241
242 #define IP4_REPLY_MARK(net, mark) \
243 ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
244
ip_is_fragment(const struct iphdr * iph)245 static 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) */
255 static inline
ip_decrease_ttl(struct iphdr * iph)256 int 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
264 static inline
ip_dont_fragment(struct sock * sk,struct dst_entry * dst)265 int 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
272 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
273
ip_select_ident(struct sk_buff * skb,struct dst_entry * dst,struct sock * sk)274 static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
275 {
276 struct iphdr *iph = ip_hdr(skb);
277
278 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
279 /* This is only to work around buggy Windows95/2000
280 * VJ compression implementations. If the ID field
281 * does not change, they drop every other packet in
282 * a TCP stream using header compression.
283 */
284 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
285 htons(inet_sk(sk)->inet_id++) : 0;
286 } else
287 __ip_select_ident(iph, dst, 0);
288 }
289
ip_select_ident_more(struct sk_buff * skb,struct dst_entry * dst,struct sock * sk,int more)290 static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
291 {
292 struct iphdr *iph = ip_hdr(skb);
293
294 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
295 if (sk && inet_sk(sk)->inet_daddr) {
296 iph->id = htons(inet_sk(sk)->inet_id);
297 inet_sk(sk)->inet_id += 1 + more;
298 } else
299 iph->id = 0;
300 } else
301 __ip_select_ident(iph, dst, more);
302 }
303
304 /*
305 * Map a multicast IP onto multicast MAC for type ethernet.
306 */
307
ip_eth_mc_map(__be32 naddr,char * buf)308 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
309 {
310 __u32 addr=ntohl(naddr);
311 buf[0]=0x01;
312 buf[1]=0x00;
313 buf[2]=0x5e;
314 buf[5]=addr&0xFF;
315 addr>>=8;
316 buf[4]=addr&0xFF;
317 addr>>=8;
318 buf[3]=addr&0x7F;
319 }
320
321 /*
322 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
323 * Leave P_Key as 0 to be filled in by driver.
324 */
325
ip_ib_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)326 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
327 {
328 __u32 addr;
329 unsigned char scope = broadcast[5] & 0xF;
330
331 buf[0] = 0; /* Reserved */
332 buf[1] = 0xff; /* Multicast QPN */
333 buf[2] = 0xff;
334 buf[3] = 0xff;
335 addr = ntohl(naddr);
336 buf[4] = 0xff;
337 buf[5] = 0x10 | scope; /* scope from broadcast address */
338 buf[6] = 0x40; /* IPv4 signature */
339 buf[7] = 0x1b;
340 buf[8] = broadcast[8]; /* P_Key */
341 buf[9] = broadcast[9];
342 buf[10] = 0;
343 buf[11] = 0;
344 buf[12] = 0;
345 buf[13] = 0;
346 buf[14] = 0;
347 buf[15] = 0;
348 buf[19] = addr & 0xff;
349 addr >>= 8;
350 buf[18] = addr & 0xff;
351 addr >>= 8;
352 buf[17] = addr & 0xff;
353 addr >>= 8;
354 buf[16] = addr & 0x0f;
355 }
356
ip_ipgre_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)357 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
358 {
359 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
360 memcpy(buf, broadcast, 4);
361 else
362 memcpy(buf, &naddr, sizeof(naddr));
363 }
364
365 #if IS_ENABLED(CONFIG_IPV6)
366 #include <linux/ipv6.h>
367 #endif
368
inet_reset_saddr(struct sock * sk)369 static __inline__ void inet_reset_saddr(struct sock *sk)
370 {
371 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
372 #if IS_ENABLED(CONFIG_IPV6)
373 if (sk->sk_family == PF_INET6) {
374 struct ipv6_pinfo *np = inet6_sk(sk);
375
376 memset(&np->saddr, 0, sizeof(np->saddr));
377 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
378 }
379 #endif
380 }
381
382 #endif
383
sk_mc_loop(struct sock * sk)384 static inline int sk_mc_loop(struct sock *sk)
385 {
386 if (!sk)
387 return 1;
388 switch (sk->sk_family) {
389 case AF_INET:
390 return inet_sk(sk)->mc_loop;
391 #if IS_ENABLED(CONFIG_IPV6)
392 case AF_INET6:
393 return inet6_sk(sk)->mc_loop;
394 #endif
395 }
396 WARN_ON(1);
397 return 1;
398 }
399
400 extern bool ip_call_ra_chain(struct sk_buff *skb);
401
402 /*
403 * Functions provided by ip_fragment.c
404 */
405
406 enum ip_defrag_users {
407 IP_DEFRAG_LOCAL_DELIVER,
408 IP_DEFRAG_CALL_RA_CHAIN,
409 IP_DEFRAG_CONNTRACK_IN,
410 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
411 IP_DEFRAG_CONNTRACK_OUT,
412 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
413 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
414 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
415 IP_DEFRAG_VS_IN,
416 IP_DEFRAG_VS_OUT,
417 IP_DEFRAG_VS_FWD,
418 IP_DEFRAG_AF_PACKET,
419 IP_DEFRAG_MACVLAN,
420 };
421
422 int ip_defrag(struct sk_buff *skb, u32 user);
423 #ifdef CONFIG_INET
424 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
425 #else
ip_check_defrag(struct sk_buff * skb,u32 user)426 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
427 {
428 return skb;
429 }
430 #endif
431 int ip_frag_mem(struct net *net);
432 int ip_frag_nqueues(struct net *net);
433
434 /*
435 * Functions provided by ip_forward.c
436 */
437
438 extern int ip_forward(struct sk_buff *skb);
439
440 /*
441 * Functions provided by ip_options.c
442 */
443
444 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
445 __be32 daddr, struct rtable *rt, int is_frag);
446 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
447 extern void ip_options_fragment(struct sk_buff *skb);
448 extern int ip_options_compile(struct net *net,
449 struct ip_options *opt, struct sk_buff *skb);
450 extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
451 unsigned char *data, int optlen);
452 extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
453 unsigned char __user *data, int optlen);
454 extern void ip_options_undo(struct ip_options * opt);
455 extern void ip_forward_options(struct sk_buff *skb);
456 extern int ip_options_rcv_srr(struct sk_buff *skb);
457
458 /*
459 * Functions provided by ip_sockglue.c
460 */
461
462 extern void ipv4_pktinfo_prepare(struct sk_buff *skb);
463 extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
464 extern int ip_cmsg_send(struct net *net,
465 struct msghdr *msg, struct ipcm_cookie *ipc);
466 extern int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
467 extern int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
468 extern int compat_ip_setsockopt(struct sock *sk, int level,
469 int optname, char __user *optval, unsigned int optlen);
470 extern int compat_ip_getsockopt(struct sock *sk, int level,
471 int optname, char __user *optval, int __user *optlen);
472 extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
473
474 extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
475 extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
476 __be16 port, u32 info, u8 *payload);
477 extern void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
478 u32 info);
479
480 #ifdef CONFIG_PROC_FS
481 extern int ip_misc_proc_init(void);
482 #endif
483
484 #endif /* _IP_H */
485