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
  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/ip.h>
  28 #include <linux/in.h>
  29
  30 #include <net/inet_sock.h>
  31 #include <net/snmp.h>
  32
  33 struct sock;
  34
  35 struct inet_skb_parm
  36 {
  37         struct ip_options       opt;            /* Compiled IP options          */
  38         unsigned char           flags;
  39
  40 #define IPSKB_FORWARDED         1
  41 #define IPSKB_XFRM_TUNNEL_SIZE  2
  42 #define IPSKB_XFRM_TRANSFORMED  4
  43 #define IPSKB_FRAG_COMPLETE     8
  44 #define IPSKB_REROUTED          16
  45 };
  46
  47 struct ipcm_cookie
  48 {
  49         u32                     addr;
  50         int                     oif;
  51         struct ip_options       *opt;
  52 };
  53
  54 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  55
  56 struct ip_ra_chain
  57 {
  58         struct ip_ra_chain      *next;
  59         struct sock             *sk;
  60         void                    (*destructor)(struct sock *);
  61 };
  62
  63 extern struct ip_ra_chain *ip_ra_chain;
  64 extern rwlock_t ip_ra_lock;
  65
  66 /* IP flags. */
  67 #define IP_CE           0x8000          /* Flag: "Congestion"           */
  68 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  69 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
  70 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  71
  72 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  73
  74 struct msghdr;
  75 struct net_device;
  76 struct packet_type;
  77 struct rtable;
  78 struct sk_buff;
  79 struct sockaddr;
  80
  81 extern void             ip_mc_dropsocket(struct sock *);
  82 extern void             ip_mc_dropdevice(struct net_device *dev);
  83 extern int              igmp_mc_proc_init(void);
  84
  85 /*
  86  *      Functions provided by ip.c
  87  */
  88
  89 extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  90                                               u32 saddr, u32 daddr,
  91                                               struct ip_options *opt);
  92 extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  93                                struct packet_type *pt, struct net_device *orig_dev);
  94 extern int              ip_local_deliver(struct sk_buff *skb);
  95 extern int              ip_mr_input(struct sk_buff *skb);
  96 extern int              ip_output(struct sk_buff *skb);
  97 extern int              ip_mc_output(struct sk_buff *skb);
  98 extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
  99 extern int              ip_do_nat(struct sk_buff *skb);
 100 extern void             ip_send_check(struct iphdr *ip);
 101 extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 102 extern void             ip_init(void);
 103 extern int              ip_append_data(struct sock *sk,
 104                                        int getfrag(void *from, char *to, int offset, int len,
 105                                                    int odd, struct sk_buff *skb),
 106                                 void *from, int len, int protolen,
 107                                 struct ipcm_cookie *ipc,
 108                                 struct rtable *rt,
 109                                 unsigned int flags);
 110 extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 111 extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 112                                 int offset, size_t size, int flags);
 113 extern int              ip_push_pending_frames(struct sock *sk);
 114 extern void             ip_flush_pending_frames(struct sock *sk);
 115
 116 /* datagram.c */
 117 extern int              ip4_datagram_connect(struct sock *sk,
 118                                              struct sockaddr *uaddr, int addr_len);
 119
 120 /*
 121  *      Map a multicast IP onto multicast MAC for type Token Ring.
 122  *      This conforms to RFC1469 Option 2 Multicasting i.e.
 123  *      using a functional address to transmit / receive
 124  *      multicast packets.
 125  */
 126
 127 static inline void ip_tr_mc_map(u32 addr, char *buf)
 128 {
 129         buf[0]=0xC0;
 130         buf[1]=0x00;
 131         buf[2]=0x00;
 132         buf[3]=0x04;
 133         buf[4]=0x00;
 134         buf[5]=0x00;
 135 }
 136
 137 struct ip_reply_arg {
 138         struct kvec iov[1];
 139         u32         csum;
 140         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 141                                 /* -1 if not needed */
 142 };
 143
 144 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 145                    unsigned int len);
 146
 147 struct ipv4_config
 148 {
 149         int     log_martians;
 150         int     autoconfig;
 151         int     no_pmtu_disc;
 152 };
 153
 154 extern struct ipv4_config ipv4_config;
 155 DECLARE_SNMP_STAT(struct ipstats_mib, ip_statistics);
 156 #define IP_INC_STATS(field)             SNMP_INC_STATS(ip_statistics, field)
 157 #define IP_INC_STATS_BH(field)          SNMP_INC_STATS_BH(ip_statistics, field)
 158 #define IP_INC_STATS_USER(field)        SNMP_INC_STATS_USER(ip_statistics, field)
 159 DECLARE_SNMP_STAT(struct linux_mib, net_statistics);
 160 #define NET_INC_STATS(field)            SNMP_INC_STATS(net_statistics, field)
 161 #define NET_INC_STATS_BH(field)         SNMP_INC_STATS_BH(net_statistics, field)
 162 #define NET_INC_STATS_USER(field)       SNMP_INC_STATS_USER(net_statistics, field)
 163 #define NET_ADD_STATS_BH(field, adnd)   SNMP_ADD_STATS_BH(net_statistics, field, adnd)
 164 #define NET_ADD_STATS_USER(field, adnd) SNMP_ADD_STATS_USER(net_statistics, field, adnd)
 165
 166 extern int sysctl_local_port_range[2];
 167 extern int sysctl_ip_default_ttl;
 168 extern int sysctl_ip_nonlocal_bind;
 169
 170 /* From ip_fragment.c */
 171 extern int sysctl_ipfrag_high_thresh;
 172 extern int sysctl_ipfrag_low_thresh;
 173 extern int sysctl_ipfrag_time;
 174 extern int sysctl_ipfrag_secret_interval;
 175 extern int sysctl_ipfrag_max_dist;
 176
 177 /* From inetpeer.c */
 178 extern int inet_peer_threshold;
 179 extern int inet_peer_minttl;
 180 extern int inet_peer_maxttl;
 181 extern int inet_peer_gc_mintime;
 182 extern int inet_peer_gc_maxtime;
 183
 184 /* From ip_output.c */
 185 extern int sysctl_ip_dynaddr;
 186
 187 extern void ipfrag_init(void);
 188
 189 #ifdef CONFIG_INET
 190 #include <net/dst.h>
 191
 192 /* The function in 2.2 was invalid, producing wrong result for
 193  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 194 static inline
 195 int ip_decrease_ttl(struct iphdr *iph)
 196 {
 197         u32 check = iph->check;
 198         check += htons(0x0100);
 199         iph->check = check + (check>=0xFFFF);
 200         return --iph->ttl;
 201 }
 202
 203 static inline
 204 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 205 {
 206         return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 207                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 208                  !(dst_metric(dst, RTAX_LOCK)&(1<<RTAX_MTU))));
 209 }
 210
 211 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 212
 213 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 214 {
 215         if (iph->frag_off & htons(IP_DF)) {
 216                 /* This is only to work around buggy Windows95/2000
 217                  * VJ compression implementations.  If the ID field
 218                  * does not change, they drop every other packet in
 219                  * a TCP stream using header compression.
 220                  */
 221                 iph->id = (sk && inet_sk(sk)->daddr) ?
 222                                         htons(inet_sk(sk)->id++) : 0;
 223         } else
 224                 __ip_select_ident(iph, dst, 0);
 225 }
 226
 227 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 228 {
 229         if (iph->frag_off & htons(IP_DF)) {
 230                 if (sk && inet_sk(sk)->daddr) {
 231                         iph->id = htons(inet_sk(sk)->id);
 232                         inet_sk(sk)->id += 1 + more;
 233                 } else
 234                         iph->id = 0;
 235         } else
 236                 __ip_select_ident(iph, dst, more);
 237 }
 238
 239 /*
 240  *      Map a multicast IP onto multicast MAC for type ethernet.
 241  */
 242
 243 static inline void ip_eth_mc_map(u32 addr, char *buf)
 244 {
 245         addr=ntohl(addr);
 246         buf[0]=0x01;
 247         buf[1]=0x00;
 248         buf[2]=0x5e;
 249         buf[5]=addr&0xFF;
 250         addr>>=8;
 251         buf[4]=addr&0xFF;
 252         addr>>=8;
 253         buf[3]=addr&0x7F;
 254 }
 255
 256 /*
 257  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 258  *      Leave P_Key as 0 to be filled in by driver.
 259  */
 260
 261 static inline void ip_ib_mc_map(u32 addr, char *buf)
 262 {
 263         buf[0]  = 0;            /* Reserved */
 264         buf[1]  = 0xff;         /* Multicast QPN */
 265         buf[2]  = 0xff;
 266         buf[3]  = 0xff;
 267         addr    = ntohl(addr);
 268         buf[4]  = 0xff;
 269         buf[5]  = 0x12;         /* link local scope */
 270         buf[6]  = 0x40;         /* IPv4 signature */
 271         buf[7]  = 0x1b;
 272         buf[8]  = 0;            /* P_Key */
 273         buf[9]  = 0;
 274         buf[10] = 0;
 275         buf[11] = 0;
 276         buf[12] = 0;
 277         buf[13] = 0;
 278         buf[14] = 0;
 279         buf[15] = 0;
 280         buf[19] = addr & 0xff;
 281         addr  >>= 8;
 282         buf[18] = addr & 0xff;
 283         addr  >>= 8;
 284         buf[17] = addr & 0xff;
 285         addr  >>= 8;
 286         buf[16] = addr & 0x0f;
 287 }
 288
 289 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 290 #include <linux/ipv6.h>
 291 #endif
 292
 293 static __inline__ void inet_reset_saddr(struct sock *sk)
 294 {
 295         inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 296 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 297         if (sk->sk_family == PF_INET6) {
 298                 struct ipv6_pinfo *np = inet6_sk(sk);
 299
 300                 memset(&np->saddr, 0, sizeof(np->saddr));
 301                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 302         }
 303 #endif
 304 }
 305
 306 #endif
 307
 308 extern int      ip_call_ra_chain(struct sk_buff *skb);
 309
 310 /*
 311  *      Functions provided by ip_fragment.o
 312  */
 313
 314 enum ip_defrag_users
 315 {
 316         IP_DEFRAG_LOCAL_DELIVER,
 317         IP_DEFRAG_CALL_RA_CHAIN,
 318         IP_DEFRAG_CONNTRACK_IN,
 319         IP_DEFRAG_CONNTRACK_OUT,
 320         IP_DEFRAG_VS_IN,
 321         IP_DEFRAG_VS_OUT,
 322         IP_DEFRAG_VS_FWD
 323 };
 324
 325 struct sk_buff *ip_defrag(struct sk_buff *skb, u32 user);
 326 extern int ip_frag_nqueues;
 327 extern atomic_t ip_frag_mem;
 328
 329 /*
 330  *      Functions provided by ip_forward.c
 331  */
 332
 333 extern int ip_forward(struct sk_buff *skb);
 334 extern int ip_net_unreachable(struct sk_buff *skb);
 335
 336 /*
 337  *      Functions provided by ip_options.c
 338  */
 339
 340 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
 341 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 342 extern void ip_options_fragment(struct sk_buff *skb);
 343 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 344 extern int ip_options_get(struct ip_options **optp,
 345                           unsigned char *data, int optlen);
 346 extern int ip_options_get_from_user(struct ip_options **optp,
 347                                     unsigned char __user *data, int optlen);
 348 extern void ip_options_undo(struct ip_options * opt);
 349 extern void ip_forward_options(struct sk_buff *skb);
 350 extern int ip_options_rcv_srr(struct sk_buff *skb);
 351
 352 /*
 353  *      Functions provided by ip_sockglue.c
 354  */
 355
 356 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 357 extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 358 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 359 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 360 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 361
 362 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 363 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 364                               u16 port, u32 info, u8 *payload);
 365 extern void     ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
 366                                u32 info);
 367
 368 /* sysctl helpers - any sysctl which holds a value that ends up being
 369  * fed into the routing cache should use these handlers.
 370  */
 371 int ipv4_doint_and_flush(ctl_table *ctl, int write,
 372                          struct file* filp, void __user *buffer,
 373                          size_t *lenp, loff_t *ppos);
 374 int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 375                                   void __user *oldval, size_t __user *oldlenp,
 376                                   void __user *newval, size_t newlen,
 377                                   void **context);
 378 #ifdef CONFIG_PROC_FS
 379 extern int ip_misc_proc_init(void);
 380 #endif
 381
 382 extern struct ctl_table ipv4_table[];
 383
 384 #endif  /* _IP_H */