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 #define IPV4_MIN_MTU            68                      /* RFC 791 */
  38
  39 struct sock;
  40
  41 struct inet_skb_parm {
  42         int                     iif;
  43         struct ip_options       opt;            /* Compiled IP options          */
  44         u16                     flags;
  45
  46 #define IPSKB_FORWARDED         BIT(0)
  47 #define IPSKB_XFRM_TUNNEL_SIZE  BIT(1)
  48 #define IPSKB_XFRM_TRANSFORMED  BIT(2)
  49 #define IPSKB_FRAG_COMPLETE     BIT(3)
  50 #define IPSKB_REROUTED          BIT(4)
  51 #define IPSKB_DOREDIRECT        BIT(5)
  52 #define IPSKB_FRAG_PMTU         BIT(6)
  53 #define IPSKB_L3SLAVE           BIT(7)
  54
  55         u16                     frag_max_size;
  56 };
  57
  58 static inline bool ipv4_l3mdev_skb(u16 flags)
  59 {
  60         return !!(flags & IPSKB_L3SLAVE);
  61 }
  62
  63 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  64 {
  65         return ip_hdr(skb)->ihl * 4;
  66 }
  67
  68 struct ipcm_cookie {
  69         struct sockcm_cookie    sockc;
  70         __be32                  addr;
  71         int                     oif;
  72         struct ip_options_rcu   *opt;
  73         __u8                    tx_flags;
  74         __u8                    ttl;
  75         __s16                   tos;
  76         char                    priority;
  77 };
  78
  79 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  80 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  81
  82 /* return enslaved device index if relevant */
  83 static inline int inet_sdif(struct sk_buff *skb)
  84 {
  85 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
  86         if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
  87                 return IPCB(skb)->iif;
  88 #endif
  89         return 0;
  90 }
  91
  92 struct ip_ra_chain {
  93         struct ip_ra_chain __rcu *next;
  94         struct sock             *sk;
  95         union {
  96                 void                    (*destructor)(struct sock *);
  97                 struct sock             *saved_sk;
  98         };
  99         struct rcu_head         rcu;
 100 };
 101
 102 extern struct ip_ra_chain __rcu *ip_ra_chain;
 103
 104 /* IP flags. */
 105 #define IP_CE           0x8000          /* Flag: "Congestion"           */
 106 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 107 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
 108 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
 109
 110 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
 111
 112 struct msghdr;
 113 struct net_device;
 114 struct packet_type;
 115 struct rtable;
 116 struct sockaddr;
 117
 118 int igmp_mc_init(void);
 119
 120 /*
 121  *      Functions provided by ip.c
 122  */
 123
 124 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
 125                           __be32 saddr, __be32 daddr,
 126                           struct ip_options_rcu *opt);
 127 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 128            struct net_device *orig_dev);
 129 int ip_local_deliver(struct sk_buff *skb);
 130 int ip_mr_input(struct sk_buff *skb);
 131 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 132 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 133 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 134                    int (*output)(struct net *, struct sock *, struct sk_buff *));
 135 void ip_send_check(struct iphdr *ip);
 136 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 137 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 138
 139 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 140 void ip_init(void);
 141 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 142                    int getfrag(void *from, char *to, int offset, int len,
 143                                int odd, struct sk_buff *skb),
 144                    void *from, int len, int protolen,
 145                    struct ipcm_cookie *ipc,
 146                    struct rtable **rt,
 147                    unsigned int flags);
 148 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 149                        struct sk_buff *skb);
 150 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 151                        int offset, size_t size, int flags);
 152 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 153                               struct sk_buff_head *queue,
 154                               struct inet_cork *cork);
 155 int ip_send_skb(struct net *net, struct sk_buff *skb);
 156 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 157 void ip_flush_pending_frames(struct sock *sk);
 158 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 159                             int getfrag(void *from, char *to, int offset,
 160                                         int len, int odd, struct sk_buff *skb),
 161                             void *from, int length, int transhdrlen,
 162                             struct ipcm_cookie *ipc, struct rtable **rtp,
 163                             unsigned int flags);
 164
 165 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 166 {
 167         return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 168 }
 169
 170 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 171 {
 172         return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 173 }
 174
 175 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 176 {
 177         return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 178 }
 179
 180 /* datagram.c */
 181 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 182 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 183
 184 void ip4_datagram_release_cb(struct sock *sk);
 185
 186 struct ip_reply_arg {
 187         struct kvec iov[1];
 188         int         flags;
 189         __wsum      csum;
 190         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 191                                 /* -1 if not needed */
 192         int         bound_dev_if;
 193         u8          tos;
 194         kuid_t      uid;
 195 };
 196
 197 #define IP_REPLY_ARG_NOSRCCHECK 1
 198
 199 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 200 {
 201         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 202 }
 203
 204 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 205                            const struct ip_options *sopt,
 206                            __be32 daddr, __be32 saddr,
 207                            const struct ip_reply_arg *arg,
 208                            unsigned int len);
 209
 210 #define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 211 #define __IP_INC_STATS(net, field)      __SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 212 #define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 213 #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_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 __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 216 #define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 217 #define __NET_INC_STATS(net, field)     __SNMP_INC_STATS((net)->mib.net_statistics, field)
 218 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 219 #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 220
 221 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 222 unsigned long snmp_fold_field(void __percpu *mib, int offt);
 223 #if BITS_PER_LONG==32
 224 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 225                          size_t syncp_offset);
 226 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 227 #else
 228 static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 229                                         size_t syncp_offset)
 230 {
 231         return snmp_get_cpu_field(mib, cpu, offct);
 232
 233 }
 234
 235 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 236 {
 237         return snmp_fold_field(mib, offt);
 238 }
 239 #endif
 240
 241 #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
 242 { \
 243         int i, c; \
 244         for_each_possible_cpu(c) { \
 245                 for (i = 0; stats_list[i].name; i++) \
 246                         buff64[i] += snmp_get_cpu_field64( \
 247                                         mib_statistic, \
 248                                         c, stats_list[i].entry, \
 249                                         offset); \
 250         } \
 251 }
 252
 253 #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
 254 { \
 255         int i, c; \
 256         for_each_possible_cpu(c) { \
 257                 for (i = 0; stats_list[i].name; i++) \
 258                         buff[i] += snmp_get_cpu_field( \
 259                                                 mib_statistic, \
 260                                                 c, stats_list[i].entry); \
 261         } \
 262 }
 263
 264 void inet_get_local_port_range(struct net *net, int *low, int *high);
 265
 266 #ifdef CONFIG_SYSCTL
 267 static inline int inet_is_local_reserved_port(struct net *net, int port)
 268 {
 269         if (!net->ipv4.sysctl_local_reserved_ports)
 270                 return 0;
 271         return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
 272 }
 273
 274 static inline bool sysctl_dev_name_is_allowed(const char *name)
 275 {
 276         return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 277 }
 278
 279 static inline int inet_prot_sock(struct net *net)
 280 {
 281         return net->ipv4.sysctl_ip_prot_sock;
 282 }
 283
 284 #else
 285 static inline int inet_is_local_reserved_port(struct net *net, int port)
 286 {
 287         return 0;
 288 }
 289
 290 static inline int inet_prot_sock(struct net *net)
 291 {
 292         return PROT_SOCK;
 293 }
 294 #endif
 295
 296 __be32 inet_current_timestamp(void);
 297
 298 /* From inetpeer.c */
 299 extern int inet_peer_threshold;
 300 extern int inet_peer_minttl;
 301 extern int inet_peer_maxttl;
 302
 303 void ipfrag_init(void);
 304
 305 void ip_static_sysctl_init(void);
 306
 307 #define IP4_REPLY_MARK(net, mark) \
 308         ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 309
 310 static inline bool ip_is_fragment(const struct iphdr *iph)
 311 {
 312         return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 313 }
 314
 315 #ifdef CONFIG_INET
 316 #include <net/dst.h>
 317
 318 /* The function in 2.2 was invalid, producing wrong result for
 319  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 320 static inline
 321 int ip_decrease_ttl(struct iphdr *iph)
 322 {
 323         u32 check = (__force u32)iph->check;
 324         check += (__force u32)htons(0x0100);
 325         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 326         return --iph->ttl;
 327 }
 328
 329 static inline
 330 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 331 {
 332         u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
 333
 334         return  pmtudisc == IP_PMTUDISC_DO ||
 335                 (pmtudisc == IP_PMTUDISC_WANT &&
 336                  !(dst_metric_locked(dst, RTAX_MTU)));
 337 }
 338
 339 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 340 {
 341         return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 342                inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 343 }
 344
 345 static inline bool ip_sk_use_pmtu(const struct sock *sk)
 346 {
 347         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 348 }
 349
 350 static inline bool ip_sk_ignore_df(const struct sock *sk)
 351 {
 352         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 353                inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 354 }
 355
 356 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 357                                                     bool forwarding)
 358 {
 359         struct net *net = dev_net(dst->dev);
 360
 361         if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 362             dst_metric_locked(dst, RTAX_MTU) ||
 363             !forwarding)
 364                 return dst_mtu(dst);
 365
 366         return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
 367 }
 368
 369 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 370                                           const struct sk_buff *skb)
 371 {
 372         if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
 373                 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 374
 375                 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 376         }
 377
 378         return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
 379 }
 380
 381 u32 ip_idents_reserve(u32 hash, int segs);
 382 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 383
 384 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
 385                                         struct sock *sk, int segs)
 386 {
 387         struct iphdr *iph = ip_hdr(skb);
 388
 389         if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
 390                 /* This is only to work around buggy Windows95/2000
 391                  * VJ compression implementations.  If the ID field
 392                  * does not change, they drop every other packet in
 393                  * a TCP stream using header compression.
 394                  */
 395                 if (sk && inet_sk(sk)->inet_daddr) {
 396                         iph->id = htons(inet_sk(sk)->inet_id);
 397                         inet_sk(sk)->inet_id += segs;
 398                 } else {
 399                         iph->id = 0;
 400                 }
 401         } else {
 402                 __ip_select_ident(net, iph, segs);
 403         }
 404 }
 405
 406 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
 407                                    struct sock *sk)
 408 {
 409         ip_select_ident_segs(net, skb, sk, 1);
 410 }
 411
 412 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 413 {
 414         return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 415                                   skb->len, proto, 0);
 416 }
 417
 418 /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 419  * Equivalent to :      flow->v4addrs.src = iph->saddr;
 420  *                      flow->v4addrs.dst = iph->daddr;
 421  */
 422 static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
 423                                             const struct iphdr *iph)
 424 {
 425         BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
 426                      offsetof(typeof(flow->addrs), v4addrs.src) +
 427                               sizeof(flow->addrs.v4addrs.src));
 428         memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
 429         flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 430 }
 431
 432 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
 433 {
 434         const struct iphdr *iph = skb_gro_network_header(skb);
 435
 436         return csum_tcpudp_nofold(iph->saddr, iph->daddr,
 437                                   skb_gro_len(skb), proto, 0);
 438 }
 439
 440 /*
 441  *      Map a multicast IP onto multicast MAC for type ethernet.
 442  */
 443
 444 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 445 {
 446         __u32 addr=ntohl(naddr);
 447         buf[0]=0x01;
 448         buf[1]=0x00;
 449         buf[2]=0x5e;
 450         buf[5]=addr&0xFF;
 451         addr>>=8;
 452         buf[4]=addr&0xFF;
 453         addr>>=8;
 454         buf[3]=addr&0x7F;
 455 }
 456
 457 /*
 458  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 459  *      Leave P_Key as 0 to be filled in by driver.
 460  */
 461
 462 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 463 {
 464         __u32 addr;
 465         unsigned char scope = broadcast[5] & 0xF;
 466
 467         buf[0]  = 0;            /* Reserved */
 468         buf[1]  = 0xff;         /* Multicast QPN */
 469         buf[2]  = 0xff;
 470         buf[3]  = 0xff;
 471         addr    = ntohl(naddr);
 472         buf[4]  = 0xff;
 473         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 474         buf[6]  = 0x40;         /* IPv4 signature */
 475         buf[7]  = 0x1b;
 476         buf[8]  = broadcast[8];         /* P_Key */
 477         buf[9]  = broadcast[9];
 478         buf[10] = 0;
 479         buf[11] = 0;
 480         buf[12] = 0;
 481         buf[13] = 0;
 482         buf[14] = 0;
 483         buf[15] = 0;
 484         buf[19] = addr & 0xff;
 485         addr  >>= 8;
 486         buf[18] = addr & 0xff;
 487         addr  >>= 8;
 488         buf[17] = addr & 0xff;
 489         addr  >>= 8;
 490         buf[16] = addr & 0x0f;
 491 }
 492
 493 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 494 {
 495         if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 496                 memcpy(buf, broadcast, 4);
 497         else
 498                 memcpy(buf, &naddr, sizeof(naddr));
 499 }
 500
 501 #if IS_ENABLED(CONFIG_IPV6)
 502 #include <linux/ipv6.h>
 503 #endif
 504
 505 static __inline__ void inet_reset_saddr(struct sock *sk)
 506 {
 507         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 508 #if IS_ENABLED(CONFIG_IPV6)
 509         if (sk->sk_family == PF_INET6) {
 510                 struct ipv6_pinfo *np = inet6_sk(sk);
 511
 512                 memset(&np->saddr, 0, sizeof(np->saddr));
 513                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 514         }
 515 #endif
 516 }
 517
 518 #endif
 519
 520 static inline unsigned int ipv4_addr_hash(__be32 ip)
 521 {
 522         return (__force unsigned int) ip;
 523 }
 524
 525 bool ip_call_ra_chain(struct sk_buff *skb);
 526
 527 /*
 528  *      Functions provided by ip_fragment.c
 529  */
 530
 531 enum ip_defrag_users {
 532         IP_DEFRAG_LOCAL_DELIVER,
 533         IP_DEFRAG_CALL_RA_CHAIN,
 534         IP_DEFRAG_CONNTRACK_IN,
 535         __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 536         IP_DEFRAG_CONNTRACK_OUT,
 537         __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 538         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 539         __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 540         IP_DEFRAG_VS_IN,
 541         IP_DEFRAG_VS_OUT,
 542         IP_DEFRAG_VS_FWD,
 543         IP_DEFRAG_AF_PACKET,
 544         IP_DEFRAG_MACVLAN,
 545 };
 546
 547 /* Return true if the value of 'user' is between 'lower_bond'
 548  * and 'upper_bond' inclusively.
 549  */
 550 static inline bool ip_defrag_user_in_between(u32 user,
 551                                              enum ip_defrag_users lower_bond,
 552                                              enum ip_defrag_users upper_bond)
 553 {
 554         return user >= lower_bond && user <= upper_bond;
 555 }
 556
 557 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
 558 #ifdef CONFIG_INET
 559 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
 560 #else
 561 static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 562 {
 563         return skb;
 564 }
 565 #endif
 566 int ip_frag_mem(struct net *net);
 567
 568 /*
 569  *      Functions provided by ip_forward.c
 570  */
 571
 572 int ip_forward(struct sk_buff *skb);
 573
 574 /*
 575  *      Functions provided by ip_options.c
 576  */
 577
 578 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 579                       __be32 daddr, struct rtable *rt, int is_frag);
 580
 581 int __ip_options_echo(struct net *net, struct ip_options *dopt,
 582                       struct sk_buff *skb, const struct ip_options *sopt);
 583 static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
 584                                   struct sk_buff *skb)
 585 {
 586         return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
 587 }
 588
 589 void ip_options_fragment(struct sk_buff *skb);
 590 int ip_options_compile(struct net *net, struct ip_options *opt,
 591                        struct sk_buff *skb);
 592 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 593                    unsigned char *data, int optlen);
 594 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 595                              unsigned char __user *data, int optlen);
 596 void ip_options_undo(struct ip_options *opt);
 597 void ip_forward_options(struct sk_buff *skb);
 598 int ip_options_rcv_srr(struct sk_buff *skb);
 599
 600 /*
 601  *      Functions provided by ip_sockglue.c
 602  */
 603
 604 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 605 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
 606                          struct sk_buff *skb, int tlen, int offset);
 607 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 608                  struct ipcm_cookie *ipc, bool allow_ipv6);
 609 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 610                   unsigned int optlen);
 611 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 612                   int __user *optlen);
 613 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 614                          char __user *optval, unsigned int optlen);
 615 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 616                          char __user *optval, int __user *optlen);
 617 int ip_ra_control(struct sock *sk, unsigned char on,
 618                   void (*destructor)(struct sock *));
 619
 620 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 621 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 622                    u32 info, u8 *payload);
 623 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 624                     u32 info);
 625
 626 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 627 {
 628         ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
 629 }
 630
 631 bool icmp_global_allow(void);
 632 extern int sysctl_icmp_msgs_per_sec;
 633 extern int sysctl_icmp_msgs_burst;
 634
 635 #ifdef CONFIG_PROC_FS
 636 int ip_misc_proc_init(void);
 637 #endif
 638
 639 #endif  /* _IP_H */