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
  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         u16                     redirport;      /* Redirect port                */
  45         unsigned char           flags;
  46
  47 #define IPSKB_MASQUERADED       1
  48 #define IPSKB_TRANSLATED        2
  49 #define IPSKB_FORWARDED         4
  50 };
  51
  52 struct ipcm_cookie
  53 {
  54         u32                     addr;
  55         int                     oif;
  56         struct ip_options       *opt;
  57 };
  58
  59 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  60
  61 struct ip_ra_chain
  62 {
  63         struct ip_ra_chain      *next;
  64         struct sock             *sk;
  65         void                    (*destructor)(struct sock *);
  66 };
  67
  68 extern struct ip_ra_chain *ip_ra_chain;
  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 device *dev);
  80 extern int              ip_mc_procinfo(char *, char **, off_t, int, int);
  81
  82 /*
  83  *      Functions provided by ip.c
  84  */
  85
  86 extern int              ip_ioctl(struct sock *sk, int cmd, unsigned long arg);
  87 extern void             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 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 void             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_id_count;
 100 extern void             ip_queue_xmit(struct sk_buff *skb);
 101 extern void             ip_init(void);
 102 extern int              ip_build_xmit(struct sock *sk,
 103                                       int getfrag (const void *,
 104                                                    char *,
 105                                                    unsigned int,
 106                                                    unsigned int),
 107                                       const void *frag,
 108                                       unsigned length,
 109                                       struct ipcm_cookie *ipc,
 110                                       struct rtable *rt,
 111                                       int flags);
 112
 113
 114 struct ip_reply_arg {
 115         struct iovec iov[2];
 116         int          n_iov;    /* redundant */
 117         u32          csum;
 118         int          csumoffset; /* u16 offset of csum in iov[0].iov_base */
 119                                  /* -1 if not needed */
 120 };
 121
 122 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 123                    unsigned int len);
 124
 125 extern int __ip_finish_output(struct sk_buff *skb);
 126
 127 struct ipv4_config
 128 {
 129         int     log_martians;
 130         int     autoconfig;
 131         int     no_pmtu_disc;
 132 };
 133
 134 extern struct ipv4_config ipv4_config;
 135 extern struct ip_mib    ip_statistics;
 136 extern struct linux_mib net_statistics;
 137
 138 extern int sysctl_local_port_range[2];
 139
 140 extern __inline__ int ip_finish_output(struct sk_buff *skb)
 141 {
 142         struct dst_entry *dst = skb->dst;
 143         struct device *dev = dst->dev;
 144         struct hh_cache *hh = dst->hh;
 145
 146         skb->dev = dev;
 147         skb->protocol = __constant_htons(ETH_P_IP);
 148
 149         if (hh) {
 150                 read_lock_irq(&hh->hh_lock);
 151                 memcpy(skb->data - 16, hh->hh_data, 16);
 152                 read_unlock_irq(&hh->hh_lock);
 153                 skb_push(skb, dev->hard_header_len);
 154                 return hh->hh_output(skb);
 155         } else if (dst->neighbour)
 156                 return dst->neighbour->output(skb);
 157
 158         kfree_skb(skb);
 159         return -EINVAL;
 160 }
 161
 162 extern __inline__ void ip_send(struct sk_buff *skb)
 163 {
 164         if (skb->len > skb->dst->pmtu)
 165                 ip_fragment(skb, __ip_finish_output);
 166         else
 167                 ip_finish_output(skb);
 168 }
 169
 170 extern __inline__
 171 int ip_decrease_ttl(struct iphdr *iph)
 172 {
 173         u16 check = iph->check;
 174         check = ntohs(check) + 0x0100;
 175         if ((check & 0xFF00) == 0)
 176                 check++;                /* carry overflow */
 177         iph->check = htons(check);
 178         return --iph->ttl;
 179 }
 180
 181 extern __inline__
 182 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 183 {
 184         return (sk->ip_pmtudisc == IP_PMTUDISC_DO ||
 185                 (sk->ip_pmtudisc == IP_PMTUDISC_WANT &&
 186                  !(dst->mxlock&(1<<RTAX_MTU))));
 187 }
 188
 189 /*
 190  *      Map a multicast IP onto multicast MAC for type ethernet.
 191  */
 192
 193 extern __inline__ void ip_eth_mc_map(u32 addr, char *buf)
 194 {
 195         addr=ntohl(addr);
 196         buf[0]=0x01;
 197         buf[1]=0x00;
 198         buf[2]=0x5e;
 199         buf[5]=addr&0xFF;
 200         addr>>=8;
 201         buf[4]=addr&0xFF;
 202         addr>>=8;
 203         buf[3]=addr&0x7F;
 204 }
 205
 206
 207 extern int      ip_call_ra_chain(struct sk_buff *skb);
 208
 209 /*
 210  *      Functions provided by ip_fragment.o
 211  */
 212
 213 struct sk_buff *ip_defrag(struct sk_buff *skb);
 214
 215 /*
 216  *      Functions provided by ip_forward.c
 217  */
 218
 219 extern int ip_forward(struct sk_buff *skb);
 220 extern int ip_net_unreachable(struct sk_buff *skb);
 221
 222 /*
 223  *      Functions provided by ip_options.c
 224  */
 225
 226 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
 227 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 228 extern void ip_options_fragment(struct sk_buff *skb);
 229 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 230 extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
 231 extern void ip_options_undo(struct ip_options * opt);
 232 extern void ip_forward_options(struct sk_buff *skb);
 233 extern int ip_options_rcv_srr(struct sk_buff *skb);
 234
 235 /*
 236  *      Functions provided by ip_sockglue.c
 237  */
 238
 239 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 240 extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 241 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen);
 242 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char *optval, int *optlen);
 243 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 244
 245 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 246 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 247                               u16 port, u32 info, u8 *payload);
 248 extern void     ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
 249                                u32 info);
 250
 251 #endif  /* _IP_H */