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_dissector.h>
  35
  36 #define IPV4_MAX_PMTU           65535U          /* RFC 2675, Section 5.1 */
  37
  38 struct sock;
  39
  40 struct inet_skb_parm {
  41         int                     iif;
  42         struct ip_options       opt;            /* Compiled IP options          */
  43         u16                     flags;
  44
  45 #define IPSKB_FORWARDED         BIT(0)
  46 #define IPSKB_XFRM_TUNNEL_SIZE  BIT(1)
  47 #define IPSKB_XFRM_TRANSFORMED  BIT(2)
  48 #define IPSKB_FRAG_COMPLETE     BIT(3)
  49 #define IPSKB_REROUTED          BIT(4)
  50 #define IPSKB_DOREDIRECT        BIT(5)
  51 #define IPSKB_FRAG_PMTU         BIT(6)
  52 #define IPSKB_L3SLAVE           BIT(7)
  53
  54         u16                     frag_max_size;
  55 };
  56
  57 static inline bool ipv4_l3mdev_skb(u16 flags)
  58 {
  59         return !!(flags & IPSKB_L3SLAVE);
  60 }
  61
  62 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  63 {
  64         return ip_hdr(skb)->ihl * 4;
  65 }
  66
  67 struct ipcm_cookie {
  68         struct sockcm_cookie    sockc;
  69         __be32                  addr;
  70         int                     oif;
  71         struct ip_options_rcu   *opt;
  72         __u8                    tx_flags;
  73         __u8                    ttl;
  74         __s16                   tos;
  75         char                    priority;
  76 };
  77
  78 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  79 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  80
  81 /* return enslaved device index if relevant */
  82 static inline int inet_sdif(struct sk_buff *skb)
  83 {
  84 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
  85         if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
  86                 return IPCB(skb)->iif;
  87 #endif
  88         return 0;
  89 }
  90
  91 struct ip_ra_chain {
  92         struct ip_ra_chain __rcu *next;
  93         struct sock             *sk;
  94         union {
  95                 void                    (*destructor)(struct sock *);
  96                 struct sock             *saved_sk;
  97         };
  98         struct rcu_head         rcu;
  99 };
 100
 101 extern struct ip_ra_chain __rcu *ip_ra_chain;
 102
 103 /* IP flags. */
 104 #define IP_CE           0x8000          /* Flag: "Congestion"           */
 105 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 106 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
 107 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
 108
 109 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
 110
 111 struct msghdr;
 112 struct net_device;
 113 struct packet_type;
 114 struct rtable;
 115 struct sockaddr;
 116
 117 int igmp_mc_init(void);
 118
 119 /*
 120  *      Functions provided by ip.c
 121  */
 122
 123 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
 124                           __be32 saddr, __be32 daddr,
 125                           struct ip_options_rcu *opt);
 126 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 127            struct net_device *orig_dev);
 128 int ip_local_deliver(struct sk_buff *skb);
 129 int ip_mr_input(struct sk_buff *skb);
 130 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 131 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 132 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 133                    int (*output)(struct net *, struct sock *, struct sk_buff *));
 134 void ip_send_check(struct iphdr *ip);
 135 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 136 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 137
 138 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 139 void ip_init(void);
 140 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 141                    int getfrag(void *from, char *to, int offset, int len,
 142                                int odd, struct sk_buff *skb),
 143                    void *from, int len, int protolen,
 144                    struct ipcm_cookie *ipc,
 145                    struct rtable **rt,
 146                    unsigned int flags);
 147 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 148                        struct sk_buff *skb);
 149 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 150                        int offset, size_t size, int flags);
 151 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 152                               struct sk_buff_head *queue,
 153                               struct inet_cork *cork);
 154 int ip_send_skb(struct net *net, struct sk_buff *skb);
 155 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 156 void ip_flush_pending_frames(struct sock *sk);
 157 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 158                             int getfrag(void *from, char *to, int offset,
 159                                         int len, int odd, struct sk_buff *skb),
 160                             void *from, int length, int transhdrlen,
 161                             struct ipcm_cookie *ipc, struct rtable **rtp,
 162                             unsigned int flags);
 163
 164 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 165 {
 166         return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 167 }
 168
 169 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 170 {
 171         return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 172 }
 173
 174 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 175 {
 176         return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 177 }
 178
 179 /* datagram.c */
 180 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 181 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 182
 183 void ip4_datagram_release_cb(struct sock *sk);
 184
 185 struct ip_reply_arg {
 186         struct kvec iov[1];
 187         int         flags;
 188         __wsum      csum;
 189         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 190                                 /* -1 if not needed */
 191         int         bound_dev_if;
 192         u8          tos;
 193         kuid_t      uid;
 194 };
 195
 196 #define IP_REPLY_ARG_NOSRCCHECK 1
 197
 198 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 199 {
 200         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 201 }
 202
 203 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 204                            const struct ip_options *sopt,
 205                            __be32 daddr, __be32 saddr,
 206                            const struct ip_reply_arg *arg,
 207                            unsigned int len);
 208
 209 #define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 210 #define __IP_INC_STATS(net, field)      __SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 211 #define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 212 #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 213 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 214 #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 215 #define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 216 #define __NET_INC_STATS(net, field)     __SNMP_INC_STATS((net)->mib.net_statistics, field)
 217 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 218 #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 219
 220 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 221 unsigned long snmp_fold_field(void __percpu *mib, int offt);
 222 #if BITS_PER_LONG==32
 223 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 224                          size_t syncp_offset);
 225 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 226 #else
 227 static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 228                                         size_t syncp_offset)
 229 {
 230         return snmp_get_cpu_field(mib, cpu, offct);
 231
 232 }
 233
 234 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 235 {
 236         return snmp_fold_field(mib, offt);
 237 }
 238 #endif
 239
 240 #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
 241 { \
 242         int i, c; \
 243         for_each_possible_cpu(c) { \
 244                 for (i = 0; stats_list[i].name; i++) \
 245                         buff64[i] += snmp_get_cpu_field64( \
 246                                         mib_statistic, \
 247                                         c, stats_list[i].entry, \
 248                                         offset); \
 249         } \
 250 }
 251
 252 #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
 253 { \
 254         int i, c; \
 255         for_each_possible_cpu(c) { \
 256                 for (i = 0; stats_list[i].name; i++) \
 257                         buff[i] += snmp_get_cpu_field( \
 258                                                 mib_statistic, \
 259                                                 c, stats_list[i].entry); \
 260         } \
 261 }
 262
 263 void inet_get_local_port_range(struct net *net, int *low, int *high);
 264
 265 #ifdef CONFIG_SYSCTL
 266 static inline int inet_is_local_reserved_port(struct net *net, int port)
 267 {
 268         if (!net->ipv4.sysctl_local_reserved_ports)
 269                 return 0;
 270         return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
 271 }
 272
 273 static inline bool sysctl_dev_name_is_allowed(const char *name)
 274 {
 275         return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 276 }
 277
 278 static inline int inet_prot_sock(struct net *net)
 279 {
 280         return net->ipv4.sysctl_ip_prot_sock;
 281 }
 282
 283 #else
 284 static inline int inet_is_local_reserved_port(struct net *net, int port)
 285 {
 286         return 0;
 287 }
 288
 289 static inline int inet_prot_sock(struct net *net)
 290 {
 291         return PROT_SOCK;
 292 }
 293 #endif
 294
 295 __be32 inet_current_timestamp(void);
 296
 297 /* From inetpeer.c */
 298 extern int inet_peer_threshold;
 299 extern int inet_peer_minttl;
 300 extern int inet_peer_maxttl;
 301
 302 void ipfrag_init(void);
 303
 304 void ip_static_sysctl_init(void);
 305
 306 #define IP4_REPLY_MARK(net, mark) \
 307         ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 308
 309 static inline bool ip_is_fragment(const struct iphdr *iph)
 310 {
 311         return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 312 }
 313
 314 #ifdef CONFIG_INET
 315 #include <net/dst.h>
 316
 317 /* The function in 2.2 was invalid, producing wrong result for
 318  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 319 static inline
 320 int ip_decrease_ttl(struct iphdr *iph)
 321 {
 322         u32 check = (__force u32)iph->check;
 323         check += (__force u32)htons(0x0100);
 324         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 325         return --iph->ttl;
 326 }
 327
 328 static inline
 329 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 330 {
 331         u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
 332
 333         return  pmtudisc == IP_PMTUDISC_DO ||
 334                 (pmtudisc == IP_PMTUDISC_WANT &&
 335                  !(dst_metric_locked(dst, RTAX_MTU)));
 336 }
 337
 338 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 339 {
 340         return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 341                inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 342 }
 343
 344 static inline bool ip_sk_use_pmtu(const struct sock *sk)
 345 {
 346         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 347 }
 348
 349 static inline bool ip_sk_ignore_df(const struct sock *sk)
 350 {
 351         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 352                inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 353 }
 354
 355 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 356                                                     bool forwarding)
 357 {
 358         struct net *net = dev_net(dst->dev);
 359
 360         if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 361             dst_metric_locked(dst, RTAX_MTU) ||
 362             !forwarding)
 363                 return dst_mtu(dst);
 364
 365         return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
 366 }
 367
 368 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 369                                           const struct sk_buff *skb)
 370 {
 371         if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
 372                 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 373
 374                 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 375         }
 376
 377         return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
 378 }
 379
 380 u32 ip_idents_reserve(u32 hash, int segs);
 381 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 382
 383 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
 384                                         struct sock *sk, int segs)
 385 {
 386         struct iphdr *iph = ip_hdr(skb);
 387
 388         if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
 389                 /* This is only to work around buggy Windows95/2000
 390                  * VJ compression implementations.  If the ID field
 391                  * does not change, they drop every other packet in
 392                  * a TCP stream using header compression.
 393                  */
 394                 if (sk && inet_sk(sk)->inet_daddr) {
 395                         iph->id = htons(inet_sk(sk)->inet_id);
 396                         inet_sk(sk)->inet_id += segs;
 397                 } else {
 398                         iph->id = 0;
 399                 }
 400         } else {
 401                 __ip_select_ident(net, iph, segs);
 402         }
 403 }
 404
 405 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
 406                                    struct sock *sk)
 407 {
 408         ip_select_ident_segs(net, skb, sk, 1);
 409 }
 410
 411 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 412 {
 413         return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 414                                   skb->len, proto, 0);
 415 }
 416
 417 /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 418  * Equivalent to :      flow->v4addrs.src = iph->saddr;
 419  *                      flow->v4addrs.dst = iph->daddr;
 420  */
 421 static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
 422                                             const struct iphdr *iph)
 423 {
 424         BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
 425                      offsetof(typeof(flow->addrs), v4addrs.src) +
 426                               sizeof(flow->addrs.v4addrs.src));
 427         memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
 428         flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 429 }
 430
 431 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
 432 {
 433         const struct iphdr *iph = skb_gro_network_header(skb);
 434
 435         return csum_tcpudp_nofold(iph->saddr, iph->daddr,
 436                                   skb_gro_len(skb), proto, 0);
 437 }
 438
 439 /*
 440  *      Map a multicast IP onto multicast MAC for type ethernet.
 441  */
 442
 443 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 444 {
 445         __u32 addr=ntohl(naddr);
 446         buf[0]=0x01;
 447         buf[1]=0x00;
 448         buf[2]=0x5e;
 449         buf[5]=addr&0xFF;
 450         addr>>=8;
 451         buf[4]=addr&0xFF;
 452         addr>>=8;
 453         buf[3]=addr&0x7F;
 454 }
 455
 456 /*
 457  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 458  *      Leave P_Key as 0 to be filled in by driver.
 459  */
 460
 461 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 462 {
 463         __u32 addr;
 464         unsigned char scope = broadcast[5] & 0xF;
 465
 466         buf[0]  = 0;            /* Reserved */
 467         buf[1]  = 0xff;         /* Multicast QPN */
 468         buf[2]  = 0xff;
 469         buf[3]  = 0xff;
 470         addr    = ntohl(naddr);
 471         buf[4]  = 0xff;
 472         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 473         buf[6]  = 0x40;         /* IPv4 signature */
 474         buf[7]  = 0x1b;
 475         buf[8]  = broadcast[8];         /* P_Key */
 476         buf[9]  = broadcast[9];
 477         buf[10] = 0;
 478         buf[11] = 0;
 479         buf[12] = 0;
 480         buf[13] = 0;
 481         buf[14] = 0;
 482         buf[15] = 0;
 483         buf[19] = addr & 0xff;
 484         addr  >>= 8;
 485         buf[18] = addr & 0xff;
 486         addr  >>= 8;
 487         buf[17] = addr & 0xff;
 488         addr  >>= 8;
 489         buf[16] = addr & 0x0f;
 490 }
 491
 492 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 493 {
 494         if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 495                 memcpy(buf, broadcast, 4);
 496         else
 497                 memcpy(buf, &naddr, sizeof(naddr));
 498 }
 499
 500 #if IS_ENABLED(CONFIG_IPV6)
 501 #include <linux/ipv6.h>
 502 #endif
 503
 504 static __inline__ void inet_reset_saddr(struct sock *sk)
 505 {
 506         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 507 #if IS_ENABLED(CONFIG_IPV6)
 508         if (sk->sk_family == PF_INET6) {
 509                 struct ipv6_pinfo *np = inet6_sk(sk);
 510
 511                 memset(&np->saddr, 0, sizeof(np->saddr));
 512                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 513         }
 514 #endif
 515 }
 516
 517 #endif
 518
 519 static inline unsigned int ipv4_addr_hash(__be32 ip)
 520 {
 521         return (__force unsigned int) ip;
 522 }
 523
 524 bool ip_call_ra_chain(struct sk_buff *skb);
 525
 526 /*
 527  *      Functions provided by ip_fragment.c
 528  */
 529
 530 enum ip_defrag_users {
 531         IP_DEFRAG_LOCAL_DELIVER,
 532         IP_DEFRAG_CALL_RA_CHAIN,
 533         IP_DEFRAG_CONNTRACK_IN,
 534         __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 535         IP_DEFRAG_CONNTRACK_OUT,
 536         __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 537         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 538         __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 539         IP_DEFRAG_VS_IN,
 540         IP_DEFRAG_VS_OUT,
 541         IP_DEFRAG_VS_FWD,
 542         IP_DEFRAG_AF_PACKET,
 543         IP_DEFRAG_MACVLAN,
 544 };
 545
 546 /* Return true if the value of 'user' is between 'lower_bond'
 547  * and 'upper_bond' inclusively.
 548  */
 549 static inline bool ip_defrag_user_in_between(u32 user,
 550                                              enum ip_defrag_users lower_bond,
 551                                              enum ip_defrag_users upper_bond)
 552 {
 553         return user >= lower_bond && user <= upper_bond;
 554 }
 555
 556 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
 557 #ifdef CONFIG_INET
 558 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
 559 #else
 560 static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 561 {
 562         return skb;
 563 }
 564 #endif
 565 int ip_frag_mem(struct net *net);
 566
 567 /*
 568  *      Functions provided by ip_forward.c
 569  */
 570
 571 int ip_forward(struct sk_buff *skb);
 572
 573 /*
 574  *      Functions provided by ip_options.c
 575  */
 576
 577 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 578                       __be32 daddr, struct rtable *rt, int is_frag);
 579
 580 int __ip_options_echo(struct net *net, struct ip_options *dopt,
 581                       struct sk_buff *skb, const struct ip_options *sopt);
 582 static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
 583                                   struct sk_buff *skb)
 584 {
 585         return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
 586 }
 587
 588 void ip_options_fragment(struct sk_buff *skb);
 589 int ip_options_compile(struct net *net, struct ip_options *opt,
 590                        struct sk_buff *skb);
 591 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 592                    unsigned char *data, int optlen);
 593 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 594                              unsigned char __user *data, int optlen);
 595 void ip_options_undo(struct ip_options *opt);
 596 void ip_forward_options(struct sk_buff *skb);
 597 int ip_options_rcv_srr(struct sk_buff *skb);
 598
 599 /*
 600  *      Functions provided by ip_sockglue.c
 601  */
 602
 603 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 604 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
 605                          struct sk_buff *skb, int tlen, int offset);
 606 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 607                  struct ipcm_cookie *ipc, bool allow_ipv6);
 608 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 609                   unsigned int optlen);
 610 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 611                   int __user *optlen);
 612 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 613                          char __user *optval, unsigned int optlen);
 614 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 615                          char __user *optval, int __user *optlen);
 616 int ip_ra_control(struct sock *sk, unsigned char on,
 617                   void (*destructor)(struct sock *));
 618
 619 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 620 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 621                    u32 info, u8 *payload);
 622 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 623                     u32 info);
 624
 625 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 626 {
 627         ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
 628 }
 629
 630 bool icmp_global_allow(void);
 631 extern int sysctl_icmp_msgs_per_sec;
 632 extern int sysctl_icmp_msgs_burst;
 633
 634 #ifdef CONFIG_PROC_FS
 635 int ip_misc_proc_init(void);
 636 #endif
 637
 638 #endif  /* _IP_H */