include/net/ip.h

   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 extern __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 extern __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 extern __inline__
 171 int ip_decrease_ttl(struct iphdr *iph)
 172 {
 173         u32 check = iph->check;
 174         check += __constant_htons(0x0100);
 175         iph->check = check + (check>>16);
 176         return --iph->ttl;
 177 }
 178
 179 extern __inline__
 180 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 181 {
 182         return (sk->protinfo.af_inet.pmtudisc == IP_PMTUDISC_DO ||
 183                 (sk->protinfo.af_inet.pmtudisc == IP_PMTUDISC_WANT &&
 184                  !(dst->mxlock&(1<<RTAX_MTU))));
 185 }
 186
 187 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst);
 188
 189 extern __inline__ void ip_select_ident(struct iphdr *iph, struct dst_entry *dst)
 190 {
 191         if (iph->frag_off&__constant_htons(IP_DF))
 192                 iph->id = 0;
 193         else
 194                 __ip_select_ident(iph, dst);
 195 }
 196
 197 /*
 198  *      Map a multicast IP onto multicast MAC for type ethernet.
 199  */
 200
 201 extern __inline__ void ip_eth_mc_map(u32 addr, char *buf)
 202 {
 203         addr=ntohl(addr);
 204         buf[0]=0x01;
 205         buf[1]=0x00;
 206         buf[2]=0x5e;
 207         buf[5]=addr&0xFF;
 208         addr>>=8;
 209         buf[4]=addr&0xFF;
 210         addr>>=8;
 211         buf[3]=addr&0x7F;
 212 }
 213
 214 #endif
 215
 216 extern int      ip_call_ra_chain(struct sk_buff *skb);
 217
 218 /*
 219  *      Functions provided by ip_fragment.o
 220  */
 221
 222 struct sk_buff *ip_defrag(struct sk_buff *skb);
 223
 224 /*
 225  *      Functions provided by ip_forward.c
 226  */
 227
 228 extern int ip_forward(struct sk_buff *skb);
 229 extern int ip_net_unreachable(struct sk_buff *skb);
 230
 231 /*
 232  *      Functions provided by ip_options.c
 233  */
 234
 235 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
 236 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 237 extern void ip_options_fragment(struct sk_buff *skb);
 238 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 239 extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
 240 extern void ip_options_undo(struct ip_options * opt);
 241 extern void ip_forward_options(struct sk_buff *skb);
 242 extern int ip_options_rcv_srr(struct sk_buff *skb);
 243
 244 /*
 245  *      Functions provided by ip_sockglue.c
 246  */
 247
 248 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 249 extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 250 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen);
 251 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char *optval, int *optlen);
 252 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 253
 254 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 255 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 256                               u16 port, u32 info, u8 *payload);
 257 extern void     ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
 258                                u32 info);
 259
 260 #endif  /* _IP_H */