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/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/route.h>
  32 #include <net/snmp.h>
  33 #include <net/flow.h>
  34 #include <net/flow_keys.h>
  35
  36 struct sock;
  37
  38 struct inet_skb_parm {
  39         struct ip_options       opt;            /* Compiled IP options          */
  40         unsigned char           flags;
  41
  42 #define IPSKB_FORWARDED         BIT(0)
  43 #define IPSKB_XFRM_TUNNEL_SIZE  BIT(1)
  44 #define IPSKB_XFRM_TRANSFORMED  BIT(2)
  45 #define IPSKB_FRAG_COMPLETE     BIT(3)
  46 #define IPSKB_REROUTED          BIT(4)
  47 #define IPSKB_DOREDIRECT        BIT(5)
  48
  49         u16                     frag_max_size;
  50 };
  51
  52 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  53 {
  54         return ip_hdr(skb)->ihl * 4;
  55 }
  56
  57 struct ipcm_cookie {
  58         __be32                  addr;
  59         int                     oif;
  60         struct ip_options_rcu   *opt;
  61         __u8                    tx_flags;
  62         __u8                    ttl;
  63         __s16                   tos;
  64         char                    priority;
  65 };
  66
  67 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  68 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  69
  70 struct ip_ra_chain {
  71         struct ip_ra_chain __rcu *next;
  72         struct sock             *sk;
  73         union {
  74                 void                    (*destructor)(struct sock *);
  75                 struct sock             *saved_sk;
  76         };
  77         struct rcu_head         rcu;
  78 };
  79
  80 extern struct ip_ra_chain __rcu *ip_ra_chain;
  81
  82 /* IP flags. */
  83 #define IP_CE           0x8000          /* Flag: "Congestion"           */
  84 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  85 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
  86 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  87
  88 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  89
  90 struct msghdr;
  91 struct net_device;
  92 struct packet_type;
  93 struct rtable;
  94 struct sockaddr;
  95
  96 int igmp_mc_init(void);
  97
  98 /*
  99  *      Functions provided by ip.c
 100  */
 101
 102 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
 103                           __be32 saddr, __be32 daddr,
 104                           struct ip_options_rcu *opt);
 105 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 106            struct net_device *orig_dev);
 107 int ip_local_deliver(struct sk_buff *skb);
 108 int ip_mr_input(struct sk_buff *skb);
 109 int ip_output(struct sock *sk, struct sk_buff *skb);
 110 int ip_mc_output(struct sock *sk, struct sk_buff *skb);
 111 int ip_fragment(struct sock *sk, struct sk_buff *skb,
 112                 int (*output)(struct sock *, struct sk_buff *));
 113 int ip_do_nat(struct sk_buff *skb);
 114 void ip_send_check(struct iphdr *ip);
 115 int __ip_local_out(struct sk_buff *skb);
 116 int ip_local_out_sk(struct sock *sk, struct sk_buff *skb);
 117 static inline int ip_local_out(struct sk_buff *skb)
 118 {
 119         return ip_local_out_sk(skb->sk, skb);
 120 }
 121
 122 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 123 void ip_init(void);
 124 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 125                    int getfrag(void *from, char *to, int offset, int len,
 126                                int odd, struct sk_buff *skb),
 127                    void *from, int len, int protolen,
 128                    struct ipcm_cookie *ipc,
 129                    struct rtable **rt,
 130                    unsigned int flags);
 131 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 132                        struct sk_buff *skb);
 133 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 134                        int offset, size_t size, int flags);
 135 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 136                               struct sk_buff_head *queue,
 137                               struct inet_cork *cork);
 138 int ip_send_skb(struct net *net, struct sk_buff *skb);
 139 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 140 void ip_flush_pending_frames(struct sock *sk);
 141 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 142                             int getfrag(void *from, char *to, int offset,
 143                                         int len, int odd, struct sk_buff *skb),
 144                             void *from, int length, int transhdrlen,
 145                             struct ipcm_cookie *ipc, struct rtable **rtp,
 146                             unsigned int flags);
 147
 148 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 149 {
 150         return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 151 }
 152
 153 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 154 {
 155         return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 156 }
 157
 158 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 159 {
 160         return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 161 }
 162
 163 /* datagram.c */
 164 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 165
 166 void ip4_datagram_release_cb(struct sock *sk);
 167
 168 struct ip_reply_arg {
 169         struct kvec iov[1];
 170         int         flags;
 171         __wsum      csum;
 172         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 173                                 /* -1 if not needed */
 174         int         bound_dev_if;
 175         u8          tos;
 176 };
 177
 178 #define IP_REPLY_ARG_NOSRCCHECK 1
 179
 180 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 181 {
 182         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 183 }
 184
 185 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 186                            const struct ip_options *sopt,
 187                            __be32 daddr, __be32 saddr,
 188                            const struct ip_reply_arg *arg,
 189                            unsigned int len);
 190
 191 #define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 192 #define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
 193 #define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 194 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
 195 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 196 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
 197 #define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 198 #define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 199 #define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 200 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 201 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 202 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 203
 204 unsigned long snmp_fold_field(void __percpu *mib, int offt);
 205 #if BITS_PER_LONG==32
 206 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 207 #else
 208 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 209 {
 210         return snmp_fold_field(mib, offt);
 211 }
 212 #endif
 213
 214 void inet_get_local_port_range(struct net *net, int *low, int *high);
 215
 216 #ifdef CONFIG_SYSCTL
 217 static inline int inet_is_local_reserved_port(struct net *net, int port)
 218 {
 219         if (!net->ipv4.sysctl_local_reserved_ports)
 220                 return 0;
 221         return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
 222 }
 223
 224 static inline bool sysctl_dev_name_is_allowed(const char *name)
 225 {
 226         return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 227 }
 228
 229 #else
 230 static inline int inet_is_local_reserved_port(struct net *net, int port)
 231 {
 232         return 0;
 233 }
 234 #endif
 235
 236 /* From inetpeer.c */
 237 extern int inet_peer_threshold;
 238 extern int inet_peer_minttl;
 239 extern int inet_peer_maxttl;
 240
 241 /* From ip_input.c */
 242 extern int sysctl_ip_early_demux;
 243
 244 /* From ip_output.c */
 245 extern int sysctl_ip_dynaddr;
 246
 247 void ipfrag_init(void);
 248
 249 void ip_static_sysctl_init(void);
 250
 251 #define IP4_REPLY_MARK(net, mark) \
 252         ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 253
 254 static inline bool ip_is_fragment(const struct iphdr *iph)
 255 {
 256         return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 257 }
 258
 259 #ifdef CONFIG_INET
 260 #include <net/dst.h>
 261
 262 /* The function in 2.2 was invalid, producing wrong result for
 263  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 264 static inline
 265 int ip_decrease_ttl(struct iphdr *iph)
 266 {
 267         u32 check = (__force u32)iph->check;
 268         check += (__force u32)htons(0x0100);
 269         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 270         return --iph->ttl;
 271 }
 272
 273 static inline
 274 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 275 {
 276         return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 277                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 278                  !(dst_metric_locked(dst, RTAX_MTU)));
 279 }
 280
 281 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 282 {
 283         return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 284                inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 285 }
 286
 287 static inline bool ip_sk_use_pmtu(const struct sock *sk)
 288 {
 289         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 290 }
 291
 292 static inline bool ip_sk_ignore_df(const struct sock *sk)
 293 {
 294         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 295                inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 296 }
 297
 298 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 299                                                     bool forwarding)
 300 {
 301         struct net *net = dev_net(dst->dev);
 302
 303         if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 304             dst_metric_locked(dst, RTAX_MTU) ||
 305             !forwarding)
 306                 return dst_mtu(dst);
 307
 308         return min(dst->dev->mtu, IP_MAX_MTU);
 309 }
 310
 311 static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb)
 312 {
 313         if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
 314                 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 315                 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 316         } else {
 317                 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
 318         }
 319 }
 320
 321 u32 ip_idents_reserve(u32 hash, int segs);
 322 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 323
 324 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
 325                                         struct sock *sk, int segs)
 326 {
 327         struct iphdr *iph = ip_hdr(skb);
 328
 329         if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
 330                 /* This is only to work around buggy Windows95/2000
 331                  * VJ compression implementations.  If the ID field
 332                  * does not change, they drop every other packet in
 333                  * a TCP stream using header compression.
 334                  */
 335                 if (sk && inet_sk(sk)->inet_daddr) {
 336                         iph->id = htons(inet_sk(sk)->inet_id);
 337                         inet_sk(sk)->inet_id += segs;
 338                 } else {
 339                         iph->id = 0;
 340                 }
 341         } else {
 342                 __ip_select_ident(net, iph, segs);
 343         }
 344 }
 345
 346 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
 347                                    struct sock *sk)
 348 {
 349         ip_select_ident_segs(net, skb, sk, 1);
 350 }
 351
 352 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 353 {
 354         return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 355                                   skb->len, proto, 0);
 356 }
 357
 358 static inline void inet_set_txhash(struct sock *sk)
 359 {
 360         struct inet_sock *inet = inet_sk(sk);
 361         struct flow_keys keys;
 362
 363         keys.src = inet->inet_saddr;
 364         keys.dst = inet->inet_daddr;
 365         keys.port16[0] = inet->inet_sport;
 366         keys.port16[1] = inet->inet_dport;
 367
 368         sk->sk_txhash = flow_hash_from_keys(&keys);
 369 }
 370
 371 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
 372 {
 373         const struct iphdr *iph = skb_gro_network_header(skb);
 374
 375         return csum_tcpudp_nofold(iph->saddr, iph->daddr,
 376                                   skb_gro_len(skb), proto, 0);
 377 }
 378
 379 /*
 380  *      Map a multicast IP onto multicast MAC for type ethernet.
 381  */
 382
 383 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 384 {
 385         __u32 addr=ntohl(naddr);
 386         buf[0]=0x01;
 387         buf[1]=0x00;
 388         buf[2]=0x5e;
 389         buf[5]=addr&0xFF;
 390         addr>>=8;
 391         buf[4]=addr&0xFF;
 392         addr>>=8;
 393         buf[3]=addr&0x7F;
 394 }
 395
 396 /*
 397  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 398  *      Leave P_Key as 0 to be filled in by driver.
 399  */
 400
 401 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 402 {
 403         __u32 addr;
 404         unsigned char scope = broadcast[5] & 0xF;
 405
 406         buf[0]  = 0;            /* Reserved */
 407         buf[1]  = 0xff;         /* Multicast QPN */
 408         buf[2]  = 0xff;
 409         buf[3]  = 0xff;
 410         addr    = ntohl(naddr);
 411         buf[4]  = 0xff;
 412         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 413         buf[6]  = 0x40;         /* IPv4 signature */
 414         buf[7]  = 0x1b;
 415         buf[8]  = broadcast[8];         /* P_Key */
 416         buf[9]  = broadcast[9];
 417         buf[10] = 0;
 418         buf[11] = 0;
 419         buf[12] = 0;
 420         buf[13] = 0;
 421         buf[14] = 0;
 422         buf[15] = 0;
 423         buf[19] = addr & 0xff;
 424         addr  >>= 8;
 425         buf[18] = addr & 0xff;
 426         addr  >>= 8;
 427         buf[17] = addr & 0xff;
 428         addr  >>= 8;
 429         buf[16] = addr & 0x0f;
 430 }
 431
 432 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 433 {
 434         if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 435                 memcpy(buf, broadcast, 4);
 436         else
 437                 memcpy(buf, &naddr, sizeof(naddr));
 438 }
 439
 440 #if IS_ENABLED(CONFIG_IPV6)
 441 #include <linux/ipv6.h>
 442 #endif
 443
 444 static __inline__ void inet_reset_saddr(struct sock *sk)
 445 {
 446         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 447 #if IS_ENABLED(CONFIG_IPV6)
 448         if (sk->sk_family == PF_INET6) {
 449                 struct ipv6_pinfo *np = inet6_sk(sk);
 450
 451                 memset(&np->saddr, 0, sizeof(np->saddr));
 452                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 453         }
 454 #endif
 455 }
 456
 457 #endif
 458
 459 bool ip_call_ra_chain(struct sk_buff *skb);
 460
 461 /*
 462  *      Functions provided by ip_fragment.c
 463  */
 464
 465 enum ip_defrag_users {
 466         IP_DEFRAG_LOCAL_DELIVER,
 467         IP_DEFRAG_CALL_RA_CHAIN,
 468         IP_DEFRAG_CONNTRACK_IN,
 469         __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 470         IP_DEFRAG_CONNTRACK_OUT,
 471         __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 472         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 473         __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 474         IP_DEFRAG_VS_IN,
 475         IP_DEFRAG_VS_OUT,
 476         IP_DEFRAG_VS_FWD,
 477         IP_DEFRAG_AF_PACKET,
 478         IP_DEFRAG_MACVLAN,
 479 };
 480
 481 int ip_defrag(struct sk_buff *skb, u32 user);
 482 #ifdef CONFIG_INET
 483 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
 484 #else
 485 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
 486 {
 487         return skb;
 488 }
 489 #endif
 490 int ip_frag_mem(struct net *net);
 491
 492 /*
 493  *      Functions provided by ip_forward.c
 494  */
 495
 496 int ip_forward(struct sk_buff *skb);
 497
 498 /*
 499  *      Functions provided by ip_options.c
 500  */
 501
 502 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 503                       __be32 daddr, struct rtable *rt, int is_frag);
 504
 505 int __ip_options_echo(struct ip_options *dopt, struct sk_buff *skb,
 506                       const struct ip_options *sopt);
 507 static inline int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
 508 {
 509         return __ip_options_echo(dopt, skb, &IPCB(skb)->opt);
 510 }
 511
 512 void ip_options_fragment(struct sk_buff *skb);
 513 int ip_options_compile(struct net *net, struct ip_options *opt,
 514                        struct sk_buff *skb);
 515 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 516                    unsigned char *data, int optlen);
 517 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 518                              unsigned char __user *data, int optlen);
 519 void ip_options_undo(struct ip_options *opt);
 520 void ip_forward_options(struct sk_buff *skb);
 521 int ip_options_rcv_srr(struct sk_buff *skb);
 522
 523 /*
 524  *      Functions provided by ip_sockglue.c
 525  */
 526
 527 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 528 void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb, int offset);
 529 int ip_cmsg_send(struct net *net, struct msghdr *msg,
 530                  struct ipcm_cookie *ipc, bool allow_ipv6);
 531 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 532                   unsigned int optlen);
 533 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 534                   int __user *optlen);
 535 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 536                          char __user *optval, unsigned int optlen);
 537 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 538                          char __user *optval, int __user *optlen);
 539 int ip_ra_control(struct sock *sk, unsigned char on,
 540                   void (*destructor)(struct sock *));
 541
 542 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 543 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 544                    u32 info, u8 *payload);
 545 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 546                     u32 info);
 547
 548 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 549 {
 550         ip_cmsg_recv_offset(msg, skb, 0);
 551 }
 552
 553 bool icmp_global_allow(void);
 554 extern int sysctl_icmp_msgs_per_sec;
 555 extern int sysctl_icmp_msgs_burst;
 556
 557 #ifdef CONFIG_PROC_FS
 558 int ip_misc_proc_init(void);
 559 #endif
 560
 561 #endif  /* _IP_H */