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
82 /*
83 * Functions provided by ip.c
84 */
85
86 extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
87 u32 saddr, u32 daddr,
88 struct ip_options *opt);
89 extern int ip_rcv(struct sk_buff *skb, struct net_device *dev,
90 struct packet_type *pt);
91 extern int ip_local_deliver(struct sk_buff *skb);
92 extern int ip_mr_input(struct sk_buff *skb);
93 extern int ip_output(struct sk_buff *skb);
94 extern int ip_mc_output(struct sk_buff *skb);
95 extern int ip_fragment(struct sk_buff *skb, int (*out)(struct sk_buff*));
96 extern int ip_do_nat(struct sk_buff *skb);
97 extern void ip_send_check(struct iphdr *ip);
98 extern int ip_queue_xmit(struct sk_buff *skb);
99 extern void ip_init(void);
100 extern int ip_build_xmit(struct sock *sk,
101 int getfrag (const void *,
102 char *,
103 unsigned int,
104 unsigned int),
105 const void *frag,
106 unsigned length,
107 struct ipcm_cookie *ipc,
108 struct rtable *rt,
109 int flags);
110
111 /*
112 * Map a multicast IP onto multicast MAC for type Token Ring.
113 * This conforms to RFC1469 Option 2 Multicasting i.e.
114 * using a functional address to transmit / receive
115 * multicast packets.
116 */
117
118 static inline void ip_tr_mc_map(u32 addr, char *buf)
119 {
120 buf[0]=0xC0;
121 buf[1]=0x00;
122 buf[2]=0x00;
123 buf[3]=0x04;
124 buf[4]=0x00;
125 buf[5]=0x00;
126 }
127
128 struct ip_reply_arg {
129 struct iovec iov[2];
130 int n_iov; /* redundant */
131 u32 csum;
132 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
133 /* -1 if not needed */
134 };
135
136 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
137 unsigned int len);
138
139 extern __inline__ int ip_finish_output(struct sk_buff *skb);
140
141 struct ipv4_config
142 {
143 int log_martians;
144 int autoconfig;
145 int no_pmtu_disc;
146 };
147
148 extern struct ipv4_config ipv4_config;
149 extern struct ip_mib ip_statistics[NR_CPUS*2];
150 #define IP_INC_STATS(field) SNMP_INC_STATS(ip_statistics, field)
151 #define IP_INC_STATS_BH(field) SNMP_INC_STATS_BH(ip_statistics, field)
152 #define IP_INC_STATS_USER(field) SNMP_INC_STATS_USER(ip_statistics, field)
153 extern struct linux_mib net_statistics[NR_CPUS*2];
154 #define NET_INC_STATS(field) SNMP_INC_STATS(net_statistics, field)
155 #define NET_INC_STATS_BH(field) SNMP_INC_STATS_BH(net_statistics, field)
156 #define NET_INC_STATS_USER(field) SNMP_INC_STATS_USER(net_statistics, field)
157
158 extern int sysctl_local_port_range[2];
159 extern int sysctl_ip_default_ttl;
160
161 #ifdef CONFIG_INET
162 static inline int ip_send(struct sk_buff *skb)
163 {
164 if (skb->len > skb->dst->pmtu)
165 return ip_fragment(skb, ip_finish_output);
166 else
167 return ip_finish_output(skb);
168 }
169
170 /* The function in 2.2 was invalid, producing wrong result for
171 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
172 static inline
173 int ip_decrease_ttl(struct iphdr *iph)
174 {
175 u32 check = iph->check;
176 check += __constant_htons(0x0100);
177 iph->check = check + (check>=0xFFFF);
178 return --iph->ttl;
179 }
180
181 static inline
182 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
183 {
184 return (sk->protinfo.af_inet.pmtudisc == IP_PMTUDISC_DO ||
185 (sk->protinfo.af_inet.pmtudisc == IP_PMTUDISC_WANT &&
186 !(dst->mxlock&(1<<RTAX_MTU))));
187 }
188
189 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst);
190
191 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst)
192 {
193 if (iph->frag_off&__constant_htons(IP_DF))
194 iph->id = 0;
195 else
196 __ip_select_ident(iph, dst);
197 }
198
199 /*
200 * Map a multicast IP onto multicast MAC for type ethernet.
201 */
202
203 static inline void ip_eth_mc_map(u32 addr, char *buf)
204 {
205 addr=ntohl(addr);
206 buf[0]=0x01;
207 buf[1]=0x00;
208 buf[2]=0x5e;
209 buf[5]=addr&0xFF;
210 addr>>=8;
211 buf[4]=addr&0xFF;
212 addr>>=8;
213 buf[3]=addr&0x7F;
214 }
215
216 #endif
217
218 extern int ip_call_ra_chain(struct sk_buff *skb);
219
220 /*
221 * Functions provided by ip_fragment.o
222 */
223
224 struct sk_buff *ip_defrag(struct sk_buff *skb);
225 extern int ip_frag_nqueues;
226 extern atomic_t ip_frag_mem;
227
228 /*
229 * Functions provided by ip_forward.c
230 */
231
232 extern int ip_forward(struct sk_buff *skb);
233 extern int ip_net_unreachable(struct sk_buff *skb);
234
235 /*
236 * Functions provided by ip_options.c
237 */
238
239 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
240 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
241 extern void ip_options_fragment(struct sk_buff *skb);
242 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
243 extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
244 extern void ip_options_undo(struct ip_options * opt);
245 extern void ip_forward_options(struct sk_buff *skb);
246 extern int ip_options_rcv_srr(struct sk_buff *skb);
247
248 /*
249 * Functions provided by ip_sockglue.c
250 */
251
252 extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
253 extern int ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
254 extern int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen);
255 extern int ip_getsockopt(struct sock *sk, int level, int optname, char *optval, int *optlen);
256 extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
257
258 extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
259 extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
260 u16 port, u32 info, u8 *payload);
261 extern void ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
262 u32 info);
263
264 #endif /* _IP_H */
265
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