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ip: use ip_hdr() in __ip_make_skb() to retrieve IP header
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CommitLineData
1da177e4
LT
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 *
02c30a84 10 * Authors: Ross Biro
1da177e4
LT
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
1da177e4 25#include <linux/types.h>
1da177e4
LT
26#include <linux/ip.h>
27#include <linux/in.h>
c9bdd4b5 28#include <linux/skbuff.h>
14c85021
ACM
29
30#include <net/inet_sock.h>
1da177e4 31#include <net/snmp.h>
86b08d86 32#include <net/flow.h>
1da177e4
LT
33
34struct sock;
35
fd2c3ef7 36struct inet_skb_parm {
1da177e4
LT
37 struct ip_options opt; /* Compiled IP options */
38 unsigned char flags;
39
8cdfab8a
PM
40#define IPSKB_FORWARDED 1
41#define IPSKB_XFRM_TUNNEL_SIZE 2
3e3850e9
PM
42#define IPSKB_XFRM_TRANSFORMED 4
43#define IPSKB_FRAG_COMPLETE 8
48d5cad8 44#define IPSKB_REROUTED 16
5f2d04f1
PM
45
46 u16 frag_max_size;
1da177e4
LT
47};
48
c9bdd4b5
ACM
49static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
50{
eddc9ec5 51 return ip_hdr(skb)->ihl * 4;
c9bdd4b5
ACM
52}
53
fd2c3ef7 54struct ipcm_cookie {
c1d18f9f 55 __be32 addr;
1da177e4 56 int oif;
f6d8bd05 57 struct ip_options_rcu *opt;
2244d07b 58 __u8 tx_flags;
1da177e4
LT
59};
60
61#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
62
fd2c3ef7 63struct ip_ra_chain {
43a951e9 64 struct ip_ra_chain __rcu *next;
1da177e4 65 struct sock *sk;
592fcb9d
ED
66 union {
67 void (*destructor)(struct sock *);
68 struct sock *saved_sk;
69 };
66018506 70 struct rcu_head rcu;
1da177e4
LT
71};
72
43a951e9 73extern struct ip_ra_chain __rcu *ip_ra_chain;
1da177e4
LT
74
75/* IP flags. */
76#define IP_CE 0x8000 /* Flag: "Congestion" */
77#define IP_DF 0x4000 /* Flag: "Don't Fragment" */
78#define IP_MF 0x2000 /* Flag: "More Fragments" */
79#define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
80
81#define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
82
14c85021
ACM
83struct msghdr;
84struct net_device;
85struct packet_type;
86struct rtable;
14c85021
ACM
87struct sockaddr;
88
1da177e4
LT
89extern int igmp_mc_proc_init(void);
90
91/*
92 * Functions provided by ip.c
93 */
94
95extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
13d8eaa0 96 __be32 saddr, __be32 daddr,
f6d8bd05 97 struct ip_options_rcu *opt);
1da177e4 98extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
f2ccd8fa 99 struct packet_type *pt, struct net_device *orig_dev);
1da177e4
LT
100extern int ip_local_deliver(struct sk_buff *skb);
101extern int ip_mr_input(struct sk_buff *skb);
102extern int ip_output(struct sk_buff *skb);
103extern int ip_mc_output(struct sk_buff *skb);
2e2f7aef 104extern int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
1da177e4
LT
105extern int ip_do_nat(struct sk_buff *skb);
106extern void ip_send_check(struct iphdr *ip);
c439cb2e
HX
107extern int __ip_local_out(struct sk_buff *skb);
108extern int ip_local_out(struct sk_buff *skb);
d9d8da80 109extern int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
1da177e4 110extern void ip_init(void);
f5fca608 111extern int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1da177e4
LT
112 int getfrag(void *from, char *to, int offset, int len,
113 int odd, struct sk_buff *skb),
114 void *from, int len, int protolen,
115 struct ipcm_cookie *ipc,
2e77d89b 116 struct rtable **rt,
1da177e4
LT
117 unsigned int flags);
118extern int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
f5fca608 119extern ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1da177e4 120 int offset, size_t size, int flags);
1c32c5ad 121extern struct sk_buff *__ip_make_skb(struct sock *sk,
77968b78 122 struct flowi4 *fl4,
1c32c5ad
HX
123 struct sk_buff_head *queue,
124 struct inet_cork *cork);
b5ec8eea 125extern int ip_send_skb(struct net *net, struct sk_buff *skb);
77968b78 126extern int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
1da177e4 127extern void ip_flush_pending_frames(struct sock *sk);
1c32c5ad 128extern struct sk_buff *ip_make_skb(struct sock *sk,
77968b78 129 struct flowi4 *fl4,
1c32c5ad
HX
130 int getfrag(void *from, char *to, int offset, int len,
131 int odd, struct sk_buff *skb),
132 void *from, int length, int transhdrlen,
133 struct ipcm_cookie *ipc,
134 struct rtable **rtp,
135 unsigned int flags);
136
77968b78 137static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
1c32c5ad 138{
77968b78 139 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
1c32c5ad 140}
1da177e4
LT
141
142/* datagram.c */
143extern int ip4_datagram_connect(struct sock *sk,
144 struct sockaddr *uaddr, int addr_len);
145
8141ed9f
SK
146extern void ip4_datagram_release_cb(struct sock *sk);
147
1da177e4
LT
148struct ip_reply_arg {
149 struct kvec iov[1];
88ef4a5a 150 int flags;
d6f5493c 151 __wsum csum;
1da177e4
LT
152 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
153 /* -1 if not needed */
f0e48dbf 154 int bound_dev_if;
66b13d99 155 u8 tos;
1da177e4
LT
156};
157
88ef4a5a
KK
158#define IP_REPLY_ARG_NOSRCCHECK 1
159
86b08d86
KK
160static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
161{
162 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
163}
164
be9f4a44 165void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
70e73416
DM
166 __be32 saddr, const struct ip_reply_arg *arg,
167 unsigned int len);
1da177e4 168
fd2c3ef7 169struct ipv4_config {
1da177e4 170 int log_martians;
1da177e4
LT
171 int no_pmtu_disc;
172};
173
174extern struct ipv4_config ipv4_config;
4ce3c183
ED
175#define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
176#define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
177#define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
178#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
179#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
180#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
61a7e260
PE
181#define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
182#define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
183#define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
184#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
185#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
1da177e4 186
7d720c3e 187extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
4ce3c183
ED
188#if BITS_PER_LONG==32
189extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
190#else
191static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
192{
193 return snmp_fold_field(mib, offt);
194}
195#endif
1823e4c8 196extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
5a17a390
CW
197
198static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
199{
200 int i;
201
202 BUG_ON(ptr == NULL);
203 for (i = 0; i < SNMP_ARRAY_SZ; i++) {
204 free_percpu(ptr[i]);
205 ptr[i] = NULL;
206 }
207}
33490170 208
3c689b73
ED
209extern struct local_ports {
210 seqlock_t lock;
211 int range[2];
212} sysctl_local_ports;
227b60f5
SH
213extern void inet_get_local_port_range(int *low, int *high);
214
e3826f1e
AW
215extern unsigned long *sysctl_local_reserved_ports;
216static inline int inet_is_reserved_local_port(int port)
217{
218 return test_bit(port, sysctl_local_reserved_ports);
219}
220
cdac4e07 221extern int sysctl_ip_nonlocal_bind;
1da177e4 222
20380731
ACM
223/* From inetpeer.c */
224extern int inet_peer_threshold;
225extern int inet_peer_minttl;
226extern int inet_peer_maxttl;
20380731 227
6648bd7e
AD
228/* From ip_input.c */
229extern int sysctl_ip_early_demux;
230
20380731
ACM
231/* From ip_output.c */
232extern int sysctl_ip_dynaddr;
233
234extern void ipfrag_init(void);
235
bd7b1533
AV
236extern void ip_static_sysctl_init(void);
237
d18cd551
DM
238static inline bool ip_is_fragment(const struct iphdr *iph)
239{
240 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
241}
242
1da177e4 243#ifdef CONFIG_INET
14c85021
ACM
244#include <net/dst.h>
245
1da177e4
LT
246/* The function in 2.2 was invalid, producing wrong result for
247 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
248static inline
249int ip_decrease_ttl(struct iphdr *iph)
250{
5c78f275
AV
251 u32 check = (__force u32)iph->check;
252 check += (__force u32)htons(0x0100);
253 iph->check = (__force __sum16)(check + (check>=0xFFFF));
1da177e4
LT
254 return --iph->ttl;
255}
256
257static inline
258int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
259{
a02cec21 260 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
1da177e4 261 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
a02cec21 262 !(dst_metric_locked(dst, RTAX_MTU)));
1da177e4
LT
263}
264
265extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
266
267static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
268{
269 if (iph->frag_off & htons(IP_DF)) {
270 /* This is only to work around buggy Windows95/2000
271 * VJ compression implementations. If the ID field
272 * does not change, they drop every other packet in
273 * a TCP stream using header compression.
274 */
c720c7e8
ED
275 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
276 htons(inet_sk(sk)->inet_id++) : 0;
1da177e4
LT
277 } else
278 __ip_select_ident(iph, dst, 0);
279}
280
281static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
282{
283 if (iph->frag_off & htons(IP_DF)) {
c720c7e8
ED
284 if (sk && inet_sk(sk)->inet_daddr) {
285 iph->id = htons(inet_sk(sk)->inet_id);
286 inet_sk(sk)->inet_id += 1 + more;
1da177e4
LT
287 } else
288 iph->id = 0;
289 } else
290 __ip_select_ident(iph, dst, more);
291}
292
293/*
294 * Map a multicast IP onto multicast MAC for type ethernet.
295 */
296
714e85be 297static inline void ip_eth_mc_map(__be32 naddr, char *buf)
1da177e4 298{
714e85be 299 __u32 addr=ntohl(naddr);
1da177e4
LT
300 buf[0]=0x01;
301 buf[1]=0x00;
302 buf[2]=0x5e;
303 buf[5]=addr&0xFF;
304 addr>>=8;
305 buf[4]=addr&0xFF;
306 addr>>=8;
307 buf[3]=addr&0x7F;
308}
309
310/*
311 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
312 * Leave P_Key as 0 to be filled in by driver.
313 */
314
a9e527e3 315static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
1da177e4 316{
714e85be 317 __u32 addr;
a9e527e3
RM
318 unsigned char scope = broadcast[5] & 0xF;
319
1da177e4
LT
320 buf[0] = 0; /* Reserved */
321 buf[1] = 0xff; /* Multicast QPN */
322 buf[2] = 0xff;
323 buf[3] = 0xff;
714e85be 324 addr = ntohl(naddr);
1da177e4 325 buf[4] = 0xff;
a9e527e3 326 buf[5] = 0x10 | scope; /* scope from broadcast address */
1da177e4
LT
327 buf[6] = 0x40; /* IPv4 signature */
328 buf[7] = 0x1b;
a9e527e3
RM
329 buf[8] = broadcast[8]; /* P_Key */
330 buf[9] = broadcast[9];
1da177e4
LT
331 buf[10] = 0;
332 buf[11] = 0;
333 buf[12] = 0;
334 buf[13] = 0;
335 buf[14] = 0;
336 buf[15] = 0;
337 buf[19] = addr & 0xff;
338 addr >>= 8;
339 buf[18] = addr & 0xff;
340 addr >>= 8;
341 buf[17] = addr & 0xff;
342 addr >>= 8;
343 buf[16] = addr & 0x0f;
344}
345
93ca3bb5
TT
346static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
347{
348 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
349 memcpy(buf, broadcast, 4);
350 else
351 memcpy(buf, &naddr, sizeof(naddr));
352}
353
dfd56b8b 354#if IS_ENABLED(CONFIG_IPV6)
1da177e4
LT
355#include <linux/ipv6.h>
356#endif
357
358static __inline__ void inet_reset_saddr(struct sock *sk)
359{
c720c7e8 360 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
dfd56b8b 361#if IS_ENABLED(CONFIG_IPV6)
1da177e4
LT
362 if (sk->sk_family == PF_INET6) {
363 struct ipv6_pinfo *np = inet6_sk(sk);
364
365 memset(&np->saddr, 0, sizeof(np->saddr));
366 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
367 }
368#endif
369}
370
371#endif
372
7ad6848c
OP
373static inline int sk_mc_loop(struct sock *sk)
374{
375 if (!sk)
376 return 1;
377 switch (sk->sk_family) {
378 case AF_INET:
379 return inet_sk(sk)->mc_loop;
dfd56b8b 380#if IS_ENABLED(CONFIG_IPV6)
7ad6848c
OP
381 case AF_INET6:
382 return inet6_sk(sk)->mc_loop;
383#endif
384 }
cd65c3c7 385 WARN_ON(1);
7ad6848c
OP
386 return 1;
387}
388
ba57b4db 389extern bool ip_call_ra_chain(struct sk_buff *skb);
1da177e4
LT
390
391/*
b798232f 392 * Functions provided by ip_fragment.c
1da177e4
LT
393 */
394
fd2c3ef7 395enum ip_defrag_users {
1da177e4
LT
396 IP_DEFRAG_LOCAL_DELIVER,
397 IP_DEFRAG_CALL_RA_CHAIN,
398 IP_DEFRAG_CONNTRACK_IN,
4be929be 399 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
1da177e4 400 IP_DEFRAG_CONNTRACK_OUT,
4be929be 401 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
8fa9ff68 402 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
4be929be 403 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
1da177e4
LT
404 IP_DEFRAG_VS_IN,
405 IP_DEFRAG_VS_OUT,
595fc71b
DM
406 IP_DEFRAG_VS_FWD,
407 IP_DEFRAG_AF_PACKET,
bc416d97 408 IP_DEFRAG_MACVLAN,
1da177e4
LT
409};
410
776c729e 411int ip_defrag(struct sk_buff *skb, u32 user);
bc416d97
ED
412#ifdef CONFIG_INET
413struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
414#else
415static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
416{
417 return skb;
418}
419#endif
6ddc0822 420int ip_frag_mem(struct net *net);
e5a2bb84 421int ip_frag_nqueues(struct net *net);
1da177e4
LT
422
423/*
424 * Functions provided by ip_forward.c
425 */
426
427extern int ip_forward(struct sk_buff *skb);
1da177e4
LT
428
429/*
430 * Functions provided by ip_options.c
431 */
432
f6d8bd05
ED
433extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
434 __be32 daddr, struct rtable *rt, int is_frag);
1da177e4
LT
435extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
436extern void ip_options_fragment(struct sk_buff *skb);
0e6bd4a1
DL
437extern int ip_options_compile(struct net *net,
438 struct ip_options *opt, struct sk_buff *skb);
f6d8bd05 439extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
4c6ea29d 440 unsigned char *data, int optlen);
f6d8bd05 441extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
4c6ea29d 442 unsigned char __user *data, int optlen);
1da177e4
LT
443extern void ip_options_undo(struct ip_options * opt);
444extern void ip_forward_options(struct sk_buff *skb);
445extern int ip_options_rcv_srr(struct sk_buff *skb);
446
447/*
448 * Functions provided by ip_sockglue.c
449 */
450
d826eb14 451extern void ipv4_pktinfo_prepare(struct sk_buff *skb);
1da177e4 452extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
7a6adb92
DL
453extern int ip_cmsg_send(struct net *net,
454 struct msghdr *msg, struct ipcm_cookie *ipc);
b7058842 455extern int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
1da177e4 456extern int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
3fdadf7d 457extern int compat_ip_setsockopt(struct sock *sk, int level,
b7058842 458 int optname, char __user *optval, unsigned int optlen);
3fdadf7d
DM
459extern int compat_ip_getsockopt(struct sock *sk, int level,
460 int optname, char __user *optval, int __user *optlen);
1da177e4
LT
461extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
462
463extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
464extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
35986b32 465 __be16 port, u32 info, u8 *payload);
0579016e 466extern void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
1da177e4
LT
467 u32 info);
468
20380731
ACM
469#ifdef CONFIG_PROC_FS
470extern int ip_misc_proc_init(void);
471#endif
472
1da177e4 473#endif /* _IP_H */