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        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
  47static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  48{
  49        return ip_hdr(skb)->ihl * 4;
  50}
  51
  52struct ipcm_cookie {
  53        __be32                  addr;
  54        int                     oif;
  55        struct ip_options_rcu   *opt;
  56        __u8                    tx_flags;
  57};
  58
  59#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  60
  61struct ip_ra_chain {
  62        struct ip_ra_chain __rcu *next;
  63        struct sock             *sk;
  64        union {
  65                void                    (*destructor)(struct sock *);
  66                struct sock             *saved_sk;
  67        };
  68        struct rcu_head         rcu;
  69};
  70
  71extern struct ip_ra_chain __rcu *ip_ra_chain;
  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_rcu *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, struct flowi *fl);
 108extern void             ip_init(void);
 109extern int              ip_append_data(struct sock *sk, struct flowi4 *fl4,
 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 flowi4 *fl4, struct page *page,
 118                                int offset, size_t size, int flags);
 119extern struct sk_buff  *__ip_make_skb(struct sock *sk,
 120                                      struct flowi4 *fl4,
 121                                      struct sk_buff_head *queue,
 122                                      struct inet_cork *cork);
 123extern int              ip_send_skb(struct sk_buff *skb);
 124extern int              ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 125extern void             ip_flush_pending_frames(struct sock *sk);
 126extern struct sk_buff  *ip_make_skb(struct sock *sk,
 127                                    struct flowi4 *fl4,
 128                                    int getfrag(void *from, char *to, int offset, int len,
 129                                                int odd, struct sk_buff *skb),
 130                                    void *from, int length, int transhdrlen,
 131                                    struct ipcm_cookie *ipc,
 132                                    struct rtable **rtp,
 133                                    unsigned int flags);
 134
 135static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 136{
 137        return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 138}
 139
 140/* datagram.c */
 141extern int              ip4_datagram_connect(struct sock *sk, 
 142                                             struct sockaddr *uaddr, int addr_len);
 143
 144/*
 145 *      Map a multicast IP onto multicast MAC for type Token Ring.
 146 *      This conforms to RFC1469 Option 2 Multicasting i.e.
 147 *      using a functional address to transmit / receive 
 148 *      multicast packets.
 149 */
 150
 151static inline void ip_tr_mc_map(__be32 addr, char *buf)
 152{
 153        buf[0]=0xC0;
 154        buf[1]=0x00;
 155        buf[2]=0x00;
 156        buf[3]=0x04;
 157        buf[4]=0x00;
 158        buf[5]=0x00;
 159}
 160
 161struct ip_reply_arg {
 162        struct kvec iov[1];   
 163        int         flags;
 164        __wsum      csum;
 165        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 166                                /* -1 if not needed */ 
 167        int         bound_dev_if;
 168}; 
 169
 170#define IP_REPLY_ARG_NOSRCCHECK 1
 171
 172static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 173{
 174        return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 175}
 176
 177void ip_send_reply(struct sock *sk, struct sk_buff *skb, __be32 daddr,
 178                   struct ip_reply_arg *arg, unsigned int len);
 179
 180struct ipv4_config {
 181        int     log_martians;
 182        int     no_pmtu_disc;
 183};
 184
 185extern struct ipv4_config ipv4_config;
 186#define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 187#define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
 188#define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 189#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
 190#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 191#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
 192#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 193#define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 194#define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 195#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 196#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 197
 198extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
 199#if BITS_PER_LONG==32
 200extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
 201#else
 202static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
 203{
 204        return snmp_fold_field(mib, offt);
 205}
 206#endif
 207extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
 208extern void snmp_mib_free(void __percpu *ptr[2]);
 209
 210extern struct local_ports {
 211        seqlock_t       lock;
 212        int             range[2];
 213} sysctl_local_ports;
 214extern void inet_get_local_port_range(int *low, int *high);
 215
 216extern unsigned long *sysctl_local_reserved_ports;
 217static inline int inet_is_reserved_local_port(int port)
 218{
 219        return test_bit(port, sysctl_local_reserved_ports);
 220}
 221
 222extern int sysctl_ip_nonlocal_bind;
 223
 224extern struct ctl_path net_core_path[];
 225extern struct ctl_path net_ipv4_ctl_path[];
 226
 227/* From inetpeer.c */
 228extern int inet_peer_threshold;
 229extern int inet_peer_minttl;
 230extern int inet_peer_maxttl;
 231extern int inet_peer_gc_mintime;
 232extern int inet_peer_gc_maxtime;
 233
 234/* From ip_output.c */
 235extern int sysctl_ip_dynaddr;
 236
 237extern void ipfrag_init(void);
 238
 239extern void ip_static_sysctl_init(void);
 240
 241#ifdef CONFIG_INET
 242#include <net/dst.h>
 243
 244/* The function in 2.2 was invalid, producing wrong result for
 245 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 246static inline
 247int ip_decrease_ttl(struct iphdr *iph)
 248{
 249        u32 check = (__force u32)iph->check;
 250        check += (__force u32)htons(0x0100);
 251        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 252        return --iph->ttl;
 253}
 254
 255static inline
 256int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 257{
 258        return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 259                (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 260                 !(dst_metric_locked(dst, RTAX_MTU)));
 261}
 262
 263extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 264
 265static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 266{
 267        if (iph->frag_off & htons(IP_DF)) {
 268                /* This is only to work around buggy Windows95/2000
 269                 * VJ compression implementations.  If the ID field
 270                 * does not change, they drop every other packet in
 271                 * a TCP stream using header compression.
 272                 */
 273                iph->id = (sk && inet_sk(sk)->inet_daddr) ?
 274                                        htons(inet_sk(sk)->inet_id++) : 0;
 275        } else
 276                __ip_select_ident(iph, dst, 0);
 277}
 278
 279static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 280{
 281        if (iph->frag_off & htons(IP_DF)) {
 282                if (sk && inet_sk(sk)->inet_daddr) {
 283                        iph->id = htons(inet_sk(sk)->inet_id);
 284                        inet_sk(sk)->inet_id += 1 + more;
 285                } else
 286                        iph->id = 0;
 287        } else
 288                __ip_select_ident(iph, dst, more);
 289}
 290
 291/*
 292 *      Map a multicast IP onto multicast MAC for type ethernet.
 293 */
 294
 295static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 296{
 297        __u32 addr=ntohl(naddr);
 298        buf[0]=0x01;
 299        buf[1]=0x00;
 300        buf[2]=0x5e;
 301        buf[5]=addr&0xFF;
 302        addr>>=8;
 303        buf[4]=addr&0xFF;
 304        addr>>=8;
 305        buf[3]=addr&0x7F;
 306}
 307
 308/*
 309 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 310 *      Leave P_Key as 0 to be filled in by driver.
 311 */
 312
 313static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 314{
 315        __u32 addr;
 316        unsigned char scope = broadcast[5] & 0xF;
 317
 318        buf[0]  = 0;            /* Reserved */
 319        buf[1]  = 0xff;         /* Multicast QPN */
 320        buf[2]  = 0xff;
 321        buf[3]  = 0xff;
 322        addr    = ntohl(naddr);
 323        buf[4]  = 0xff;
 324        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 325        buf[6]  = 0x40;         /* IPv4 signature */
 326        buf[7]  = 0x1b;
 327        buf[8]  = broadcast[8];         /* P_Key */
 328        buf[9]  = broadcast[9];
 329        buf[10] = 0;
 330        buf[11] = 0;
 331        buf[12] = 0;
 332        buf[13] = 0;
 333        buf[14] = 0;
 334        buf[15] = 0;
 335        buf[19] = addr & 0xff;
 336        addr  >>= 8;
 337        buf[18] = addr & 0xff;
 338        addr  >>= 8;
 339        buf[17] = addr & 0xff;
 340        addr  >>= 8;
 341        buf[16] = addr & 0x0f;
 342}
 343
 344static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 345{
 346        if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 347                memcpy(buf, broadcast, 4);
 348        else
 349                memcpy(buf, &naddr, sizeof(naddr));
 350}
 351
 352#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 353#include <linux/ipv6.h>
 354#endif
 355
 356static __inline__ void inet_reset_saddr(struct sock *sk)
 357{
 358        inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 359#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 360        if (sk->sk_family == PF_INET6) {
 361                struct ipv6_pinfo *np = inet6_sk(sk);
 362
 363                memset(&np->saddr, 0, sizeof(np->saddr));
 364                memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 365        }
 366#endif
 367}
 368
 369#endif
 370
 371static inline int sk_mc_loop(struct sock *sk)
 372{
 373        if (!sk)
 374                return 1;
 375        switch (sk->sk_family) {
 376        case AF_INET:
 377                return inet_sk(sk)->mc_loop;
 378#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 379        case AF_INET6:
 380                return inet6_sk(sk)->mc_loop;
 381#endif
 382        }
 383        WARN_ON(1);
 384        return 1;
 385}
 386
 387extern int      ip_call_ra_chain(struct sk_buff *skb);
 388
 389/*
 390 *      Functions provided by ip_fragment.c
 391 */
 392
 393enum ip_defrag_users {
 394        IP_DEFRAG_LOCAL_DELIVER,
 395        IP_DEFRAG_CALL_RA_CHAIN,
 396        IP_DEFRAG_CONNTRACK_IN,
 397        __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 398        IP_DEFRAG_CONNTRACK_OUT,
 399        __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 400        IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 401        __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 402        IP_DEFRAG_VS_IN,
 403        IP_DEFRAG_VS_OUT,
 404        IP_DEFRAG_VS_FWD
 405};
 406
 407int ip_defrag(struct sk_buff *skb, u32 user);
 408int ip_frag_mem(struct net *net);
 409int ip_frag_nqueues(struct net *net);
 410
 411/*
 412 *      Functions provided by ip_forward.c
 413 */
 414 
 415extern int ip_forward(struct sk_buff *skb);
 416 
 417/*
 418 *      Functions provided by ip_options.c
 419 */
 420 
 421extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 422                             __be32 daddr, struct rtable *rt, int is_frag);
 423extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 424extern void ip_options_fragment(struct sk_buff *skb);
 425extern int ip_options_compile(struct net *net,
 426                              struct ip_options *opt, struct sk_buff *skb);
 427extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 428                          unsigned char *data, int optlen);
 429extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 430                                    unsigned char __user *data, int optlen);
 431extern void ip_options_undo(struct ip_options * opt);
 432extern void ip_forward_options(struct sk_buff *skb);
 433extern int ip_options_rcv_srr(struct sk_buff *skb);
 434
 435/*
 436 *      Functions provided by ip_sockglue.c
 437 */
 438
 439extern int      ip_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
 440extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 441extern int      ip_cmsg_send(struct net *net,
 442                             struct msghdr *msg, struct ipcm_cookie *ipc);
 443extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
 444extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 445extern int      compat_ip_setsockopt(struct sock *sk, int level,
 446                        int optname, char __user *optval, unsigned int optlen);
 447extern int      compat_ip_getsockopt(struct sock *sk, int level,
 448                        int optname, char __user *optval, int __user *optlen);
 449extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 450
 451extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 452extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 
 453                              __be16 port, u32 info, u8 *payload);
 454extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 455                               u32 info);
 456
 457#ifdef CONFIG_PROC_FS
 458extern int ip_misc_proc_init(void);
 459#endif
 460
 461#endif  /* _IP_H */
 462