linux/include/net/ip.h
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   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/types.h>
  26#include <linux/ip.h>
  27#include <linux/in.h>
  28
  29#include <net/inet_sock.h>
  30#include <net/snmp.h>
  31
  32struct sock;
  33
  34struct inet_skb_parm
  35{
  36        struct ip_options       opt;            /* Compiled IP options          */
  37        unsigned char           flags;
  38
  39#define IPSKB_FORWARDED         1
  40#define IPSKB_XFRM_TUNNEL_SIZE  2
  41#define IPSKB_XFRM_TRANSFORMED  4
  42#define IPSKB_FRAG_COMPLETE     8
  43#define IPSKB_REROUTED          16
  44};
  45
  46struct ipcm_cookie
  47{
  48        u32                     addr;
  49        int                     oif;
  50        struct ip_options       *opt;
  51};
  52
  53#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  54
  55struct ip_ra_chain
  56{
  57        struct ip_ra_chain      *next;
  58        struct sock             *sk;
  59        void                    (*destructor)(struct sock *);
  60};
  61
  62extern struct ip_ra_chain *ip_ra_chain;
  63extern rwlock_t ip_ra_lock;
  64
  65/* IP flags. */
  66#define IP_CE           0x8000          /* Flag: "Congestion"           */
  67#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  68#define IP_MF           0x2000          /* Flag: "More Fragments"       */
  69#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  70
  71#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  72
  73struct msghdr;
  74struct net_device;
  75struct packet_type;
  76struct rtable;
  77struct sk_buff;
  78struct sockaddr;
  79
  80extern void             ip_mc_dropsocket(struct sock *);
  81extern void             ip_mc_dropdevice(struct net_device *dev);
  82extern int              igmp_mc_proc_init(void);
  83
  84/*
  85 *      Functions provided by ip.c
  86 */
  87
  88extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  89                                              u32 saddr, u32 daddr,
  90                                              struct ip_options *opt);
  91extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  92                               struct packet_type *pt, struct net_device *orig_dev);
  93extern int              ip_local_deliver(struct sk_buff *skb);
  94extern int              ip_mr_input(struct sk_buff *skb);
  95extern int              ip_output(struct sk_buff *skb);
  96extern int              ip_mc_output(struct sk_buff *skb);
  97extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
  98extern int              ip_do_nat(struct sk_buff *skb);
  99extern void             ip_send_check(struct iphdr *ip);
 100extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 101extern void             ip_init(void);
 102extern int              ip_append_data(struct sock *sk,
 103                                       int getfrag(void *from, char *to, int offset, int len,
 104                                                   int odd, struct sk_buff *skb),
 105                                void *from, int len, int protolen,
 106                                struct ipcm_cookie *ipc,
 107                                struct rtable *rt,
 108                                unsigned int flags);
 109extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 110extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 111                                int offset, size_t size, int flags);
 112extern int              ip_push_pending_frames(struct sock *sk);
 113extern void             ip_flush_pending_frames(struct sock *sk);
 114
 115/* datagram.c */
 116extern int              ip4_datagram_connect(struct sock *sk, 
 117                                             struct sockaddr *uaddr, int addr_len);
 118
 119/*
 120 *      Map a multicast IP onto multicast MAC for type Token Ring.
 121 *      This conforms to RFC1469 Option 2 Multicasting i.e.
 122 *      using a functional address to transmit / receive 
 123 *      multicast packets.
 124 */
 125
 126static inline void ip_tr_mc_map(u32 addr, char *buf)
 127{
 128        buf[0]=0xC0;
 129        buf[1]=0x00;
 130        buf[2]=0x00;
 131        buf[3]=0x04;
 132        buf[4]=0x00;
 133        buf[5]=0x00;
 134}
 135
 136struct ip_reply_arg {
 137        struct kvec iov[1];   
 138        u32         csum; 
 139        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 140                                /* -1 if not needed */ 
 141}; 
 142
 143void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 144                   unsigned int len); 
 145
 146struct ipv4_config
 147{
 148        int     log_martians;
 149        int     no_pmtu_disc;
 150};
 151
 152extern struct ipv4_config ipv4_config;
 153DECLARE_SNMP_STAT(struct ipstats_mib, ip_statistics);
 154#define IP_INC_STATS(field)             SNMP_INC_STATS(ip_statistics, field)
 155#define IP_INC_STATS_BH(field)          SNMP_INC_STATS_BH(ip_statistics, field)
 156#define IP_INC_STATS_USER(field)        SNMP_INC_STATS_USER(ip_statistics, field)
 157DECLARE_SNMP_STAT(struct linux_mib, net_statistics);
 158#define NET_INC_STATS(field)            SNMP_INC_STATS(net_statistics, field)
 159#define NET_INC_STATS_BH(field)         SNMP_INC_STATS_BH(net_statistics, field)
 160#define NET_INC_STATS_USER(field)       SNMP_INC_STATS_USER(net_statistics, field)
 161#define NET_ADD_STATS_BH(field, adnd)   SNMP_ADD_STATS_BH(net_statistics, field, adnd)
 162#define NET_ADD_STATS_USER(field, adnd) SNMP_ADD_STATS_USER(net_statistics, field, adnd)
 163
 164extern int sysctl_local_port_range[2];
 165extern int sysctl_ip_default_ttl;
 166extern int sysctl_ip_nonlocal_bind;
 167
 168/* From ip_fragment.c */
 169extern int sysctl_ipfrag_high_thresh; 
 170extern int sysctl_ipfrag_low_thresh;
 171extern int sysctl_ipfrag_time;
 172extern int sysctl_ipfrag_secret_interval;
 173extern int sysctl_ipfrag_max_dist;
 174
 175/* From inetpeer.c */
 176extern int inet_peer_threshold;
 177extern int inet_peer_minttl;
 178extern int inet_peer_maxttl;
 179extern int inet_peer_gc_mintime;
 180extern int inet_peer_gc_maxtime;
 181
 182/* From ip_output.c */
 183extern int sysctl_ip_dynaddr;
 184
 185extern void ipfrag_init(void);
 186
 187#ifdef CONFIG_INET
 188#include <net/dst.h>
 189
 190/* The function in 2.2 was invalid, producing wrong result for
 191 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 192static inline
 193int ip_decrease_ttl(struct iphdr *iph)
 194{
 195        u32 check = iph->check;
 196        check += htons(0x0100);
 197        iph->check = check + (check>=0xFFFF);
 198        return --iph->ttl;
 199}
 200
 201static inline
 202int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 203{
 204        return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 205                (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 206                 !(dst_metric(dst, RTAX_LOCK)&(1<<RTAX_MTU))));
 207}
 208
 209extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 210
 211static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 212{
 213        if (iph->frag_off & htons(IP_DF)) {
 214                /* This is only to work around buggy Windows95/2000
 215                 * VJ compression implementations.  If the ID field
 216                 * does not change, they drop every other packet in
 217                 * a TCP stream using header compression.
 218                 */
 219                iph->id = (sk && inet_sk(sk)->daddr) ?
 220                                        htons(inet_sk(sk)->id++) : 0;
 221        } else
 222                __ip_select_ident(iph, dst, 0);
 223}
 224
 225static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 226{
 227        if (iph->frag_off & htons(IP_DF)) {
 228                if (sk && inet_sk(sk)->daddr) {
 229                        iph->id = htons(inet_sk(sk)->id);
 230                        inet_sk(sk)->id += 1 + more;
 231                } else
 232                        iph->id = 0;
 233        } else
 234                __ip_select_ident(iph, dst, more);
 235}
 236
 237/*
 238 *      Map a multicast IP onto multicast MAC for type ethernet.
 239 */
 240
 241static inline void ip_eth_mc_map(u32 addr, char *buf)
 242{
 243        addr=ntohl(addr);
 244        buf[0]=0x01;
 245        buf[1]=0x00;
 246        buf[2]=0x5e;
 247        buf[5]=addr&0xFF;
 248        addr>>=8;
 249        buf[4]=addr&0xFF;
 250        addr>>=8;
 251        buf[3]=addr&0x7F;
 252}
 253
 254/*
 255 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 256 *      Leave P_Key as 0 to be filled in by driver.
 257 */
 258
 259static inline void ip_ib_mc_map(u32 addr, char *buf)
 260{
 261        buf[0]  = 0;            /* Reserved */
 262        buf[1]  = 0xff;         /* Multicast QPN */
 263        buf[2]  = 0xff;
 264        buf[3]  = 0xff;
 265        addr    = ntohl(addr);
 266        buf[4]  = 0xff;
 267        buf[5]  = 0x12;         /* link local scope */
 268        buf[6]  = 0x40;         /* IPv4 signature */
 269        buf[7]  = 0x1b;
 270        buf[8]  = 0;            /* P_Key */
 271        buf[9]  = 0;
 272        buf[10] = 0;
 273        buf[11] = 0;
 274        buf[12] = 0;
 275        buf[13] = 0;
 276        buf[14] = 0;
 277        buf[15] = 0;
 278        buf[19] = addr & 0xff;
 279        addr  >>= 8;
 280        buf[18] = addr & 0xff;
 281        addr  >>= 8;
 282        buf[17] = addr & 0xff;
 283        addr  >>= 8;
 284        buf[16] = addr & 0x0f;
 285}
 286
 287#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 288#include <linux/ipv6.h>
 289#endif
 290
 291static __inline__ void inet_reset_saddr(struct sock *sk)
 292{
 293        inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 294#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 295        if (sk->sk_family == PF_INET6) {
 296                struct ipv6_pinfo *np = inet6_sk(sk);
 297
 298                memset(&np->saddr, 0, sizeof(np->saddr));
 299                memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 300        }
 301#endif
 302}
 303
 304#endif
 305
 306extern int      ip_call_ra_chain(struct sk_buff *skb);
 307
 308/*
 309 *      Functions provided by ip_fragment.o
 310 */
 311
 312enum ip_defrag_users
 313{
 314        IP_DEFRAG_LOCAL_DELIVER,
 315        IP_DEFRAG_CALL_RA_CHAIN,
 316        IP_DEFRAG_CONNTRACK_IN,
 317        IP_DEFRAG_CONNTRACK_OUT,
 318        IP_DEFRAG_VS_IN,
 319        IP_DEFRAG_VS_OUT,
 320        IP_DEFRAG_VS_FWD
 321};
 322
 323struct sk_buff *ip_defrag(struct sk_buff *skb, u32 user);
 324extern int ip_frag_nqueues;
 325extern atomic_t ip_frag_mem;
 326
 327/*
 328 *      Functions provided by ip_forward.c
 329 */
 330 
 331extern int ip_forward(struct sk_buff *skb);
 332extern int ip_net_unreachable(struct sk_buff *skb);
 333 
 334/*
 335 *      Functions provided by ip_options.c
 336 */
 337 
 338extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
 339extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 340extern void ip_options_fragment(struct sk_buff *skb);
 341extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 342extern int ip_options_get(struct ip_options **optp,
 343                          unsigned char *data, int optlen);
 344extern int ip_options_get_from_user(struct ip_options **optp,
 345                                    unsigned char __user *data, int optlen);
 346extern void ip_options_undo(struct ip_options * opt);
 347extern void ip_forward_options(struct sk_buff *skb);
 348extern int ip_options_rcv_srr(struct sk_buff *skb);
 349
 350/*
 351 *      Functions provided by ip_sockglue.c
 352 */
 353
 354extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 355extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 356extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 357extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 358extern int      compat_ip_setsockopt(struct sock *sk, int level,
 359                        int optname, char __user *optval, int optlen);
 360extern int      compat_ip_getsockopt(struct sock *sk, int level,
 361                        int optname, char __user *optval, int __user *optlen);
 362extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 363
 364extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 365extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 
 366                              u16 port, u32 info, u8 *payload);
 367extern void     ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
 368                               u32 info);
 369
 370/* sysctl helpers - any sysctl which holds a value that ends up being
 371 * fed into the routing cache should use these handlers.
 372 */
 373int ipv4_doint_and_flush(ctl_table *ctl, int write,
 374                         struct file* filp, void __user *buffer,
 375                         size_t *lenp, loff_t *ppos);
 376int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 377                                  void __user *oldval, size_t __user *oldlenp,
 378                                  void __user *newval, size_t newlen, 
 379                                  void **context);
 380#ifdef CONFIG_PROC_FS
 381extern int ip_misc_proc_init(void);
 382#endif
 383
 384extern struct ctl_table ipv4_table[];
 385
 386#endif  /* _IP_H */
 387
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