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, <bir7@leland.Stanford.Edu>
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/config.h>
26 #include <linux/types.h>
27 #include <linux/socket.h>
28 #include <linux/ip.h>
29 #include <linux/netdevice.h>
30 #include <linux/inetdevice.h>
31 #include <linux/in_route.h>
32 #include <net/route.h>
33 #include <net/arp.h>
34
35 #ifndef _SNMP_H
36 #include <net/snmp.h>
37 #endif
38
39 #include <net/sock.h> /* struct sock */
40
41 struct inet_skb_parm
42 {
43 struct ip_options opt; /* Compiled IP options */
44 unsigned char flags;
45
46 #define IPSKB_MASQUERADED 1
47 #define IPSKB_TRANSLATED 2
48 #define IPSKB_FORWARDED 4
49 };
50
51 struct ipcm_cookie
52 {
53 u32 addr;
54 int oif;
55 struct ip_options *opt;
56 };
57
58 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
59
60 struct ip_ra_chain
61 {
62 struct ip_ra_chain *next;
63 struct sock *sk;
64 void (*destructor)(struct sock *);
65 };
66
67 extern struct ip_ra_chain *ip_ra_chain;
68 extern rwlock_t ip_ra_lock;
69
70 /* IP flags. */
71 #define IP_CE 0x8000 /* Flag: "Congestion" */
72 #define IP_DF 0x4000 /* Flag: "Don't Fragment" */
73 #define IP_MF 0x2000 /* Flag: "More Fragments" */
74 #define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
75
76 #define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
77
78 extern void ip_mc_dropsocket(struct sock *);
79 extern void ip_mc_dropdevice(struct net_device *dev);
80 extern int ip_mc_procinfo(char *, char **, off_t, int);
81 extern int ip_mcf_procinfo(char *, char **, off_t, int);
82
83 /*
84 * Functions provided by ip.c
85 */
86
87 extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
88 u32 saddr, u32 daddr,
89 struct ip_options *opt);
90 extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
91 struct packet_type *pt);
92 extern int ip_local_deliver(struct sk_buff *skb);
93 extern int ip_mr_input(struct sk_buff *skb);
94 extern int ip_output(struct sk_buff *skb);
95 extern int ip_mc_output(struct sk_buff *skb);
96 extern int ip_fragment(struct sk_buff *skb, int (*out)(struct sk_buff*));
97 extern int ip_do_nat(struct sk_buff *skb);
98 extern void ip_send_check(struct iphdr *ip);
99 extern int ip_queue_xmit(struct sk_buff *skb, int ipfragok);
100 extern void ip_init(void);
101 extern int ip_build_xmit(struct sock *sk,
102 int getfrag (const void *,
103 char *,
104 unsigned int,
105 unsigned int,
106 struct sk_buff *),
107 const void *frag,
108 unsigned length,
109 struct ipcm_cookie *ipc,
110 struct rtable *rt,
111 int flags);
112
113 /*
114 * Map a multicast IP onto multicast MAC for type Token Ring.
115 * This conforms to RFC1469 Option 2 Multicasting i.e.
116 * using a functional address to transmit / receive
117 * multicast packets.
118 */
119
ip_tr_mc_map(u32 addr,char * buf)120 static inline void ip_tr_mc_map(u32 addr, char *buf)
121 {
122 buf[0]=0xC0;
123 buf[1]=0x00;
124 buf[2]=0x00;
125 buf[3]=0x04;
126 buf[4]=0x00;
127 buf[5]=0x00;
128 }
129
130 struct ip_reply_arg {
131 struct iovec iov[2];
132 int n_iov; /* redundant */
133 u32 csum;
134 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
135 /* -1 if not needed */
136 };
137
138 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
139 unsigned int len);
140
141 extern int ip_finish_output(struct sk_buff *skb);
142
143 struct ipv4_config
144 {
145 int log_martians;
146 int autoconfig;
147 int no_pmtu_disc;
148 };
149
150 extern struct ipv4_config ipv4_config;
151 extern struct ip_mib ip_statistics[NR_CPUS*2];
152 #define IP_INC_STATS(field) SNMP_INC_STATS(ip_statistics, field)
153 #define IP_INC_STATS_BH(field) SNMP_INC_STATS_BH(ip_statistics, field)
154 #define IP_INC_STATS_USER(field) SNMP_INC_STATS_USER(ip_statistics, field)
155 extern struct linux_mib net_statistics[NR_CPUS*2];
156 #define NET_INC_STATS(field) SNMP_INC_STATS(net_statistics, field)
157 #define NET_INC_STATS_BH(field) SNMP_INC_STATS_BH(net_statistics, field)
158 #define NET_INC_STATS_USER(field) SNMP_INC_STATS_USER(net_statistics, field)
159
160 extern int sysctl_local_port_range[2];
161 extern int sysctl_ip_default_ttl;
162
163 #ifdef CONFIG_INET
ip_send(struct sk_buff * skb)164 static inline int ip_send(struct sk_buff *skb)
165 {
166 if (skb->len > skb->dst->pmtu)
167 return ip_fragment(skb, ip_finish_output);
168 else
169 return ip_finish_output(skb);
170 }
171
172 /* The function in 2.2 was invalid, producing wrong result for
173 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
174 static inline
ip_decrease_ttl(struct iphdr * iph)175 int ip_decrease_ttl(struct iphdr *iph)
176 {
177 u32 check = iph->check;
178 check += __constant_htons(0x0100);
179 iph->check = check + (check>=0xFFFF);
180 return --iph->ttl;
181 }
182
183 static inline
ip_dont_fragment(struct sock * sk,struct dst_entry * dst)184 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
185 {
186 return (sk->protinfo.af_inet.pmtudisc == IP_PMTUDISC_DO ||
187 (sk->protinfo.af_inet.pmtudisc == IP_PMTUDISC_WANT &&
188 !(dst->mxlock&(1<<RTAX_MTU))));
189 }
190
191 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst);
192
ip_select_ident(struct iphdr * iph,struct dst_entry * dst,struct sock * sk)193 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
194 {
195 if (iph->frag_off&__constant_htons(IP_DF)) {
196 /* This is only to work around buggy Windows95/2000
197 * VJ compression implementations. If the ID field
198 * does not change, they drop every other packet in
199 * a TCP stream using header compression.
200 */
201 iph->id = ((sk && sk->daddr) ? htons(sk->protinfo.af_inet.id++) : 0);
202 } else
203 __ip_select_ident(iph, dst);
204 }
205
206 /*
207 * Map a multicast IP onto multicast MAC for type ethernet.
208 */
209
ip_eth_mc_map(u32 addr,char * buf)210 static inline void ip_eth_mc_map(u32 addr, char *buf)
211 {
212 addr=ntohl(addr);
213 buf[0]=0x01;
214 buf[1]=0x00;
215 buf[2]=0x5e;
216 buf[5]=addr&0xFF;
217 addr>>=8;
218 buf[4]=addr&0xFF;
219 addr>>=8;
220 buf[3]=addr&0x7F;
221 }
222
223 #endif
224
225 extern int ip_call_ra_chain(struct sk_buff *skb);
226
227 /*
228 * Functions provided by ip_fragment.o
229 */
230
231 enum ip_defrag_users
232 {
233 IP_DEFRAG_LOCAL_DELIVER,
234 IP_DEFRAG_CALL_RA_CHAIN,
235 IP_DEFRAG_CONNTRACK_IN,
236 IP_DEFRAG_CONNTRACK_OUT,
237 IP_DEFRAG_NAT_OUT,
238 IP_DEFRAG_VS_OUT,
239 IP_DEFRAG_VS_FWD
240 };
241
242 struct sk_buff *ip_defrag(struct sk_buff *skb, u32 user);
243 extern int ip_frag_nqueues;
244 extern atomic_t ip_frag_mem;
245
246 /*
247 * Functions provided by ip_forward.c
248 */
249
250 extern int ip_forward(struct sk_buff *skb);
251 extern int ip_net_unreachable(struct sk_buff *skb);
252
253 /*
254 * Functions provided by ip_options.c
255 */
256
257 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
258 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
259 extern void ip_options_fragment(struct sk_buff *skb);
260 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
261 extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
262 extern void ip_options_undo(struct ip_options * opt);
263 extern void ip_forward_options(struct sk_buff *skb);
264 extern int ip_options_rcv_srr(struct sk_buff *skb);
265
266 /*
267 * Functions provided by ip_sockglue.c
268 */
269
270 extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
271 extern int ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
272 extern int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen);
273 extern int ip_getsockopt(struct sock *sk, int level, int optname, char *optval, int *optlen);
274 extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
275
276 extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
277 extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
278 u16 port, u32 info, u8 *payload);
279 extern void ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
280 u32 info);
281
282 #endif /* _IP_H */
283