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 41struct 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 51struct 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 60struct ip_ra_chain 61{ 62 struct ip_ra_chain *next; 63 struct sock *sk; 64 void (*destructor)(struct sock *); 65}; 66 67extern struct ip_ra_chain *ip_ra_chain; 68extern 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 78extern void ip_mc_dropsocket(struct sock *); 79extern void ip_mc_dropdevice(struct net_device *dev); 80extern int ip_mc_procinfo(char *, char **, off_t, int); 81 82/* 83 * Functions provided by ip.c 84 */ 85 86extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 87 u32 saddr, u32 daddr, 88 struct ip_options *opt); 89extern int ip_rcv(struct sk_buff *skb, struct net_device *dev, 90 struct packet_type *pt); 91extern int ip_local_deliver(struct sk_buff *skb); 92extern int ip_mr_input(struct sk_buff *skb); 93extern int ip_output(struct sk_buff *skb); 94extern int ip_mc_output(struct sk_buff *skb); 95extern int ip_fragment(struct sk_buff *skb, int (*out)(struct sk_buff*)); 96extern int ip_do_nat(struct sk_buff *skb); 97extern void ip_send_check(struct iphdr *ip); 98extern int ip_queue_xmit(struct sk_buff *skb); 99extern void ip_init(void); 100extern 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 118static 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 128struct 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 136void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, 137 unsigned int len); 138 139extern __inline__ int ip_finish_output(struct sk_buff *skb); 140 141struct ipv4_config 142{ 143 int log_martians; 144 int autoconfig; 145 int no_pmtu_disc; 146}; 147 148extern struct ipv4_config ipv4_config; 149extern 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) 153extern 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 158extern int sysctl_local_port_range[2]; 159extern int sysctl_ip_default_ttl; 160 161#ifdef CONFIG_INET 162static 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) */ 172static inline 173int 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 181static inline 182int 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 189extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst); 190 191static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk) 192{ 193 if (iph->frag_off&__constant_htons(IP_DF)) { 194 /* This is only to work around buggy Windows95/2000 195 * VJ compression implementations. If the ID field 196 * does not change, they drop every other packet in 197 * a TCP stream using header compression. 198 */ 199 iph->id = ((sk && sk->daddr) ? htons(sk->protinfo.af_inet.id++) : 0); 200 } else 201 __ip_select_ident(iph, dst); 202} 203 204/* 205 * Map a multicast IP onto multicast MAC for type ethernet. 206 */ 207 208static inline void ip_eth_mc_map(u32 addr, char *buf) 209{ 210 addr=ntohl(addr); 211 buf[0]=0x01; 212 buf[1]=0x00; 213 buf[2]=0x5e; 214 buf[5]=addr&0xFF; 215 addr>>=8; 216 buf[4]=addr&0xFF; 217 addr>>=8; 218 buf[3]=addr&0x7F; 219} 220 221#endif 222 223extern int ip_call_ra_chain(struct sk_buff *skb); 224 225/* 226 * Functions provided by ip_fragment.o 227 */ 228 229struct sk_buff *ip_defrag(struct sk_buff *skb); 230extern int ip_frag_nqueues; 231extern atomic_t ip_frag_mem; 232 233/* 234 * Functions provided by ip_forward.c 235 */ 236 237extern int ip_forward(struct sk_buff *skb); 238extern int ip_net_unreachable(struct sk_buff *skb); 239 240/* 241 * Functions provided by ip_options.c 242 */ 243 244extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag); 245extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb); 246extern void ip_options_fragment(struct sk_buff *skb); 247extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb); 248extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user); 249extern void ip_options_undo(struct ip_options * opt); 250extern void ip_forward_options(struct sk_buff *skb); 251extern int ip_options_rcv_srr(struct sk_buff *skb); 252 253/* 254 * Functions provided by ip_sockglue.c 255 */ 256 257extern void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb); 258extern int ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc); 259extern int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen); 260extern int ip_getsockopt(struct sock *sk, int level, int optname, char *optval, int *optlen); 261extern int ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *)); 262 263extern int ip_recv_error(struct sock *sk, struct msghdr *msg, int len); 264extern void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 265 u16 port, u32 info, u8 *payload); 266extern void ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport, 267 u32 info); 268 269#endif /* _IP_H */ 270