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#include <linux/skbuff.h>
  29
  30#include <net/inet_sock.h>
  31#include <net/snmp.h>
  32#include <net/flow.h>
  33
  34struct sock;
  35
  36struct inet_skb_parm
  37{
  38        struct ip_options       opt;            /* Compiled IP options          */
  39        unsigned char           flags;
  40
  41#define IPSKB_FORWARDED         1
  42#define IPSKB_XFRM_TUNNEL_SIZE  2
  43#define IPSKB_XFRM_TRANSFORMED  4
  44#define IPSKB_FRAG_COMPLETE     8
  45#define IPSKB_REROUTED          16
  46};
  47
  48static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  49{
  50        return ip_hdr(skb)->ihl * 4;
  51}
  52
  53struct ipcm_cookie
  54{
  55        __be32                  addr;
  56        int                     oif;
  57        struct ip_options       *opt;
  58        union skb_shared_tx     shtx;
  59};
  60
  61#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  62
  63struct ip_ra_chain
  64{
  65        struct ip_ra_chain      *next;
  66        struct sock             *sk;
  67        void                    (*destructor)(struct sock *);
  68};
  69
  70extern struct ip_ra_chain *ip_ra_chain;
  71extern rwlock_t ip_ra_lock;
  72
  73/* IP flags. */
  74#define IP_CE           0x8000          /* Flag: "Congestion"           */
  75#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  76#define IP_MF           0x2000          /* Flag: "More Fragments"       */
  77#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  78
  79#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  80
  81struct msghdr;
  82struct net_device;
  83struct packet_type;
  84struct rtable;
  85struct sockaddr;
  86
  87extern int              igmp_mc_proc_init(void);
  88
  89/*
  90 *      Functions provided by ip.c
  91 */
  92
  93extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  94                                              __be32 saddr, __be32 daddr,
  95                                              struct ip_options *opt);
  96extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  97                               struct packet_type *pt, struct net_device *orig_dev);
  98extern int              ip_local_deliver(struct sk_buff *skb);
  99extern int              ip_mr_input(struct sk_buff *skb);
 100extern int              ip_output(struct sk_buff *skb);
 101extern int              ip_mc_output(struct sk_buff *skb);
 102extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 103extern int              ip_do_nat(struct sk_buff *skb);
 104extern void             ip_send_check(struct iphdr *ip);
 105extern int              __ip_local_out(struct sk_buff *skb);
 106extern int              ip_local_out(struct sk_buff *skb);
 107extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 108extern void             ip_init(void);
 109extern int              ip_append_data(struct sock *sk,
 110                                       int getfrag(void *from, char *to, int offset, int len,
 111                                                   int odd, struct sk_buff *skb),
 112                                void *from, int len, int protolen,
 113                                struct ipcm_cookie *ipc,
 114                                struct rtable **rt,
 115                                unsigned int flags);
 116extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 117extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 118                                int offset, size_t size, int flags);
 119extern int              ip_push_pending_frames(struct sock *sk);
 120extern void             ip_flush_pending_frames(struct sock *sk);
 121
 122/* datagram.c */
 123extern int              ip4_datagram_connect(struct sock *sk, 
 124                                             struct sockaddr *uaddr, int addr_len);
 125
 126/*
 127 *      Map a multicast IP onto multicast MAC for type Token Ring.
 128 *      This conforms to RFC1469 Option 2 Multicasting i.e.
 129 *      using a functional address to transmit / receive 
 130 *      multicast packets.
 131 */
 132
 133static inline void ip_tr_mc_map(__be32 addr, char *buf)
 134{
 135        buf[0]=0xC0;
 136        buf[1]=0x00;
 137        buf[2]=0x00;
 138        buf[3]=0x04;
 139        buf[4]=0x00;
 140        buf[5]=0x00;
 141}
 142
 143struct ip_reply_arg {
 144        struct kvec iov[1];   
 145        int         flags;
 146        __wsum      csum;
 147        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 148                                /* -1 if not needed */ 
 149        int         bound_dev_if;
 150}; 
 151
 152#define IP_REPLY_ARG_NOSRCCHECK 1
 153
 154static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 155{
 156        return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 157}
 158
 159void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 160                   unsigned int len); 
 161
 162struct ipv4_config
 163{
 164        int     log_martians;
 165        int     no_pmtu_disc;
 166};
 167
 168extern struct ipv4_config ipv4_config;
 169#define IP_INC_STATS(net, field)        SNMP_INC_STATS((net)->mib.ip_statistics, field)
 170#define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS_BH((net)->mib.ip_statistics, field)
 171#define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS((net)->mib.ip_statistics, field, val)
 172#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS_BH((net)->mib.ip_statistics, field, val)
 173#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS((net)->mib.ip_statistics, field, val)
 174#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS_BH((net)->mib.ip_statistics, field, val)
 175#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 176#define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 177#define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 178#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 179#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 180
 181extern unsigned long snmp_fold_field(void *mib[], int offt);
 182extern int snmp_mib_init(void *ptr[2], size_t mibsize);
 183extern void snmp_mib_free(void *ptr[2]);
 184
 185extern struct local_ports {
 186        seqlock_t       lock;
 187        int             range[2];
 188} sysctl_local_ports;
 189extern void inet_get_local_port_range(int *low, int *high);
 190
 191extern int sysctl_ip_default_ttl;
 192extern int sysctl_ip_nonlocal_bind;
 193
 194extern struct ctl_path net_core_path[];
 195extern struct ctl_path net_ipv4_ctl_path[];
 196
 197/* From inetpeer.c */
 198extern int inet_peer_threshold;
 199extern int inet_peer_minttl;
 200extern int inet_peer_maxttl;
 201extern int inet_peer_gc_mintime;
 202extern int inet_peer_gc_maxtime;
 203
 204/* From ip_output.c */
 205extern int sysctl_ip_dynaddr;
 206
 207extern void ipfrag_init(void);
 208
 209extern void ip_static_sysctl_init(void);
 210
 211#ifdef CONFIG_INET
 212#include <net/dst.h>
 213
 214/* The function in 2.2 was invalid, producing wrong result for
 215 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 216static inline
 217int ip_decrease_ttl(struct iphdr *iph)
 218{
 219        u32 check = (__force u32)iph->check;
 220        check += (__force u32)htons(0x0100);
 221        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 222        return --iph->ttl;
 223}
 224
 225static inline
 226int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 227{
 228        return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 229                (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 230                 !(dst_metric_locked(dst, RTAX_MTU))));
 231}
 232
 233extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 234
 235static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 236{
 237        if (iph->frag_off & htons(IP_DF)) {
 238                /* This is only to work around buggy Windows95/2000
 239                 * VJ compression implementations.  If the ID field
 240                 * does not change, they drop every other packet in
 241                 * a TCP stream using header compression.
 242                 */
 243                iph->id = (sk && inet_sk(sk)->daddr) ?
 244                                        htons(inet_sk(sk)->id++) : 0;
 245        } else
 246                __ip_select_ident(iph, dst, 0);
 247}
 248
 249static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 250{
 251        if (iph->frag_off & htons(IP_DF)) {
 252                if (sk && inet_sk(sk)->daddr) {
 253                        iph->id = htons(inet_sk(sk)->id);
 254                        inet_sk(sk)->id += 1 + more;
 255                } else
 256                        iph->id = 0;
 257        } else
 258                __ip_select_ident(iph, dst, more);
 259}
 260
 261/*
 262 *      Map a multicast IP onto multicast MAC for type ethernet.
 263 */
 264
 265static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 266{
 267        __u32 addr=ntohl(naddr);
 268        buf[0]=0x01;
 269        buf[1]=0x00;
 270        buf[2]=0x5e;
 271        buf[5]=addr&0xFF;
 272        addr>>=8;
 273        buf[4]=addr&0xFF;
 274        addr>>=8;
 275        buf[3]=addr&0x7F;
 276}
 277
 278/*
 279 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 280 *      Leave P_Key as 0 to be filled in by driver.
 281 */
 282
 283static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 284{
 285        __u32 addr;
 286        unsigned char scope = broadcast[5] & 0xF;
 287
 288        buf[0]  = 0;            /* Reserved */
 289        buf[1]  = 0xff;         /* Multicast QPN */
 290        buf[2]  = 0xff;
 291        buf[3]  = 0xff;
 292        addr    = ntohl(naddr);
 293        buf[4]  = 0xff;
 294        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 295        buf[6]  = 0x40;         /* IPv4 signature */
 296        buf[7]  = 0x1b;
 297        buf[8]  = broadcast[8];         /* P_Key */
 298        buf[9]  = broadcast[9];
 299        buf[10] = 0;
 300        buf[11] = 0;
 301        buf[12] = 0;
 302        buf[13] = 0;
 303        buf[14] = 0;
 304        buf[15] = 0;
 305        buf[19] = addr & 0xff;
 306        addr  >>= 8;
 307        buf[18] = addr & 0xff;
 308        addr  >>= 8;
 309        buf[17] = addr & 0xff;
 310        addr  >>= 8;
 311        buf[16] = addr & 0x0f;
 312}
 313
 314#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 315#include <linux/ipv6.h>
 316#endif
 317
 318static __inline__ void inet_reset_saddr(struct sock *sk)
 319{
 320        inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 321#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 322        if (sk->sk_family == PF_INET6) {
 323                struct ipv6_pinfo *np = inet6_sk(sk);
 324
 325                memset(&np->saddr, 0, sizeof(np->saddr));
 326                memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 327        }
 328#endif
 329}
 330
 331#endif
 332
 333extern int      ip_call_ra_chain(struct sk_buff *skb);
 334
 335/*
 336 *      Functions provided by ip_fragment.c
 337 */
 338
 339enum ip_defrag_users
 340{
 341        IP_DEFRAG_LOCAL_DELIVER,
 342        IP_DEFRAG_CALL_RA_CHAIN,
 343        IP_DEFRAG_CONNTRACK_IN,
 344        IP_DEFRAG_CONNTRACK_OUT,
 345        IP_DEFRAG_VS_IN,
 346        IP_DEFRAG_VS_OUT,
 347        IP_DEFRAG_VS_FWD
 348};
 349
 350int ip_defrag(struct sk_buff *skb, u32 user);
 351int ip_frag_mem(struct net *net);
 352int ip_frag_nqueues(struct net *net);
 353
 354/*
 355 *      Functions provided by ip_forward.c
 356 */
 357 
 358extern int ip_forward(struct sk_buff *skb);
 359 
 360/*
 361 *      Functions provided by ip_options.c
 362 */
 363 
 364extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag);
 365extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 366extern void ip_options_fragment(struct sk_buff *skb);
 367extern int ip_options_compile(struct net *net,
 368                              struct ip_options *opt, struct sk_buff *skb);
 369extern int ip_options_get(struct net *net, struct ip_options **optp,
 370                          unsigned char *data, int optlen);
 371extern int ip_options_get_from_user(struct net *net, struct ip_options **optp,
 372                                    unsigned char __user *data, int optlen);
 373extern void ip_options_undo(struct ip_options * opt);
 374extern void ip_forward_options(struct sk_buff *skb);
 375extern int ip_options_rcv_srr(struct sk_buff *skb);
 376
 377/*
 378 *      Functions provided by ip_sockglue.c
 379 */
 380
 381extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 382extern int      ip_cmsg_send(struct net *net,
 383                             struct msghdr *msg, struct ipcm_cookie *ipc);
 384extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
 385extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 386extern int      compat_ip_setsockopt(struct sock *sk, int level,
 387                        int optname, char __user *optval, unsigned int optlen);
 388extern int      compat_ip_getsockopt(struct sock *sk, int level,
 389                        int optname, char __user *optval, int __user *optlen);
 390extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 391
 392extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 393extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 
 394                              __be16 port, u32 info, u8 *payload);
 395extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 396                               u32 info);
 397
 398/* sysctl helpers - any sysctl which holds a value that ends up being
 399 * fed into the routing cache should use these handlers.
 400 */
 401int ipv4_doint_and_flush(ctl_table *ctl, int write,
 402                         void __user *buffer,
 403                         size_t *lenp, loff_t *ppos);
 404int ipv4_doint_and_flush_strategy(ctl_table *table,
 405                                  void __user *oldval, size_t __user *oldlenp,
 406                                  void __user *newval, size_t newlen);
 407#ifdef CONFIG_PROC_FS
 408extern int ip_misc_proc_init(void);
 409#endif
 410
 411#endif  /* _IP_H */
 412