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
  35 struct sock;
  36
  37 struct inet_skb_parm {
  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         u16                     frag_max_size;
  48 };
  49
  50 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  51 {
  52         return ip_hdr(skb)->ihl * 4;
  53 }
  54
  55 struct ipcm_cookie {
  56         __be32                  addr;
  57         int                     oif;
  58         struct ip_options_rcu   *opt;
  59         __u8                    tx_flags;
  60         __u8                    ttl;
  61         __s16                   tos;
  62         char                    priority;
  63 };
  64
  65 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  66 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  67
  68 struct ip_ra_chain {
  69         struct ip_ra_chain __rcu *next;
  70         struct sock             *sk;
  71         union {
  72                 void                    (*destructor)(struct sock *);
  73                 struct sock             *saved_sk;
  74         };
  75         struct rcu_head         rcu;
  76 };
  77
  78 extern struct ip_ra_chain __rcu *ip_ra_chain;
  79
  80 /* IP flags. */
  81 #define IP_CE           0x8000          /* Flag: "Congestion"           */
  82 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  83 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
  84 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  85
  86 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  87
  88 struct msghdr;
  89 struct net_device;
  90 struct packet_type;
  91 struct rtable;
  92 struct sockaddr;
  93
  94 int igmp_mc_init(void);
  95
  96 /*
  97  *      Functions provided by ip.c
  98  */
  99
 100 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
 101                           __be32 saddr, __be32 daddr,
 102                           struct ip_options_rcu *opt);
 103 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 104            struct net_device *orig_dev);
 105 int ip_local_deliver(struct sk_buff *skb);
 106 int ip_mr_input(struct sk_buff *skb);
 107 int ip_output(struct sock *sk, struct sk_buff *skb);
 108 int ip_mc_output(struct sock *sk, struct sk_buff *skb);
 109 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 110 int ip_do_nat(struct sk_buff *skb);
 111 void ip_send_check(struct iphdr *ip);
 112 int __ip_local_out(struct sk_buff *skb);
 113 int ip_local_out_sk(struct sock *sk, struct sk_buff *skb);
 114 static inline int ip_local_out(struct sk_buff *skb)
 115 {
 116         return ip_local_out_sk(skb->sk, skb);
 117 }
 118
 119 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 120 void ip_init(void);
 121 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 122                    int getfrag(void *from, char *to, int offset, int len,
 123                                int odd, struct sk_buff *skb),
 124                    void *from, int len, int protolen,
 125                    struct ipcm_cookie *ipc,
 126                    struct rtable **rt,
 127                    unsigned int flags);
 128 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 129                        struct sk_buff *skb);
 130 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 131                        int offset, size_t size, int flags);
 132 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 133                               struct sk_buff_head *queue,
 134                               struct inet_cork *cork);
 135 int ip_send_skb(struct net *net, struct sk_buff *skb);
 136 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 137 void ip_flush_pending_frames(struct sock *sk);
 138 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 139                             int getfrag(void *from, char *to, int offset,
 140                                         int len, int odd, struct sk_buff *skb),
 141                             void *from, int length, int transhdrlen,
 142                             struct ipcm_cookie *ipc, struct rtable **rtp,
 143                             unsigned int flags);
 144
 145 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 146 {
 147         return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 148 }
 149
 150 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 151 {
 152         return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 153 }
 154
 155 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 156 {
 157         return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 158 }
 159
 160 /* datagram.c */
 161 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 162
 163 void ip4_datagram_release_cb(struct sock *sk);
 164
 165 struct ip_reply_arg {
 166         struct kvec iov[1];
 167         int         flags;
 168         __wsum      csum;
 169         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 170                                 /* -1 if not needed */
 171         int         bound_dev_if;
 172         u8          tos;
 173 };
 174
 175 #define IP_REPLY_ARG_NOSRCCHECK 1
 176
 177 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 178 {
 179         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 180 }
 181
 182 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
 183                            __be32 saddr, const struct ip_reply_arg *arg,
 184                            unsigned int len);
 185
 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(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 196 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 197 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 198
 199 unsigned long snmp_fold_field(void __percpu *mib[], int offt);
 200 #if BITS_PER_LONG==32
 201 u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
 202 #else
 203 static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
 204 {
 205         return snmp_fold_field(mib, offt);
 206 }
 207 #endif
 208 int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
 209
 210 static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
 211 {
 212         int i;
 213
 214         BUG_ON(ptr == NULL);
 215         for (i = 0; i < SNMP_ARRAY_SZ; i++) {
 216                 free_percpu(ptr[i]);
 217                 ptr[i] = NULL;
 218         }
 219 }
 220
 221 void inet_get_local_port_range(struct net *net, int *low, int *high);
 222
 223 extern unsigned long *sysctl_local_reserved_ports;
 224 static inline int inet_is_reserved_local_port(int port)
 225 {
 226         return test_bit(port, sysctl_local_reserved_ports);
 227 }
 228
 229 extern int sysctl_ip_nonlocal_bind;
 230
 231 /* From inetpeer.c */
 232 extern int inet_peer_threshold;
 233 extern int inet_peer_minttl;
 234 extern int inet_peer_maxttl;
 235
 236 /* From ip_input.c */
 237 extern int sysctl_ip_early_demux;
 238
 239 /* From ip_output.c */
 240 extern int sysctl_ip_dynaddr;
 241
 242 void ipfrag_init(void);
 243
 244 void ip_static_sysctl_init(void);
 245
 246 static inline bool ip_is_fragment(const struct iphdr *iph)
 247 {
 248         return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 249 }
 250
 251 #ifdef CONFIG_INET
 252 #include <net/dst.h>
 253
 254 /* The function in 2.2 was invalid, producing wrong result for
 255  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 256 static inline
 257 int ip_decrease_ttl(struct iphdr *iph)
 258 {
 259         u32 check = (__force u32)iph->check;
 260         check += (__force u32)htons(0x0100);
 261         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 262         return --iph->ttl;
 263 }
 264
 265 static inline
 266 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 267 {
 268         return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 269                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 270                  !(dst_metric_locked(dst, RTAX_MTU)));
 271 }
 272
 273 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 274 {
 275         return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 276                inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 277 }
 278
 279 static inline bool ip_sk_use_pmtu(const struct sock *sk)
 280 {
 281         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 282 }
 283
 284 static inline bool ip_sk_local_df(const struct sock *sk)
 285 {
 286         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 287                inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 288 }
 289
 290 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 291                                                     bool forwarding)
 292 {
 293         struct net *net = dev_net(dst->dev);
 294
 295         if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 296             dst_metric_locked(dst, RTAX_MTU) ||
 297             !forwarding)
 298                 return dst_mtu(dst);
 299
 300         return min(dst->dev->mtu, IP_MAX_MTU);
 301 }
 302
 303 static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb)
 304 {
 305         if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
 306                 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 307                 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 308         } else {
 309                 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
 310         }
 311 }
 312
 313 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 314
 315 static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
 316 {
 317         struct iphdr *iph = ip_hdr(skb);
 318
 319         if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
 320                 /* This is only to work around buggy Windows95/2000
 321                  * VJ compression implementations.  If the ID field
 322                  * does not change, they drop every other packet in
 323                  * a TCP stream using header compression.
 324                  */
 325                 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
 326                                         htons(inet_sk(sk)->inet_id++) : 0;
 327         } else
 328                 __ip_select_ident(iph, dst, 0);
 329 }
 330
 331 static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
 332 {
 333         struct iphdr *iph = ip_hdr(skb);
 334
 335         if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
 336                 if (sk && inet_sk(sk)->inet_daddr) {
 337                         iph->id = htons(inet_sk(sk)->inet_id);
 338                         inet_sk(sk)->inet_id += 1 + more;
 339                 } else
 340                         iph->id = 0;
 341         } else
 342                 __ip_select_ident(iph, dst, more);
 343 }
 344
 345 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 346 {
 347         return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 348                                   skb->len, proto, 0);
 349 }
 350
 351 /*
 352  *      Map a multicast IP onto multicast MAC for type ethernet.
 353  */
 354
 355 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 356 {
 357         __u32 addr=ntohl(naddr);
 358         buf[0]=0x01;
 359         buf[1]=0x00;
 360         buf[2]=0x5e;
 361         buf[5]=addr&0xFF;
 362         addr>>=8;
 363         buf[4]=addr&0xFF;
 364         addr>>=8;
 365         buf[3]=addr&0x7F;
 366 }
 367
 368 /*
 369  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 370  *      Leave P_Key as 0 to be filled in by driver.
 371  */
 372
 373 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 374 {
 375         __u32 addr;
 376         unsigned char scope = broadcast[5] & 0xF;
 377
 378         buf[0]  = 0;            /* Reserved */
 379         buf[1]  = 0xff;         /* Multicast QPN */
 380         buf[2]  = 0xff;
 381         buf[3]  = 0xff;
 382         addr    = ntohl(naddr);
 383         buf[4]  = 0xff;
 384         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 385         buf[6]  = 0x40;         /* IPv4 signature */
 386         buf[7]  = 0x1b;
 387         buf[8]  = broadcast[8];         /* P_Key */
 388         buf[9]  = broadcast[9];
 389         buf[10] = 0;
 390         buf[11] = 0;
 391         buf[12] = 0;
 392         buf[13] = 0;
 393         buf[14] = 0;
 394         buf[15] = 0;
 395         buf[19] = addr & 0xff;
 396         addr  >>= 8;
 397         buf[18] = addr & 0xff;
 398         addr  >>= 8;
 399         buf[17] = addr & 0xff;
 400         addr  >>= 8;
 401         buf[16] = addr & 0x0f;
 402 }
 403
 404 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 405 {
 406         if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 407                 memcpy(buf, broadcast, 4);
 408         else
 409                 memcpy(buf, &naddr, sizeof(naddr));
 410 }
 411
 412 #if IS_ENABLED(CONFIG_IPV6)
 413 #include <linux/ipv6.h>
 414 #endif
 415
 416 static __inline__ void inet_reset_saddr(struct sock *sk)
 417 {
 418         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 419 #if IS_ENABLED(CONFIG_IPV6)
 420         if (sk->sk_family == PF_INET6) {
 421                 struct ipv6_pinfo *np = inet6_sk(sk);
 422
 423                 memset(&np->saddr, 0, sizeof(np->saddr));
 424                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 425         }
 426 #endif
 427 }
 428
 429 #endif
 430
 431 static inline int sk_mc_loop(struct sock *sk)
 432 {
 433         if (!sk)
 434                 return 1;
 435         switch (sk->sk_family) {
 436         case AF_INET:
 437                 return inet_sk(sk)->mc_loop;
 438 #if IS_ENABLED(CONFIG_IPV6)
 439         case AF_INET6:
 440                 return inet6_sk(sk)->mc_loop;
 441 #endif
 442         }
 443         WARN_ON(1);
 444         return 1;
 445 }
 446
 447 bool ip_call_ra_chain(struct sk_buff *skb);
 448
 449 /*
 450  *      Functions provided by ip_fragment.c
 451  */
 452
 453 enum ip_defrag_users {
 454         IP_DEFRAG_LOCAL_DELIVER,
 455         IP_DEFRAG_CALL_RA_CHAIN,
 456         IP_DEFRAG_CONNTRACK_IN,
 457         __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 458         IP_DEFRAG_CONNTRACK_OUT,
 459         __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 460         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 461         __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 462         IP_DEFRAG_VS_IN,
 463         IP_DEFRAG_VS_OUT,
 464         IP_DEFRAG_VS_FWD,
 465         IP_DEFRAG_AF_PACKET,
 466         IP_DEFRAG_MACVLAN,
 467 };
 468
 469 int ip_defrag(struct sk_buff *skb, u32 user);
 470 #ifdef CONFIG_INET
 471 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
 472 #else
 473 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
 474 {
 475         return skb;
 476 }
 477 #endif
 478 int ip_frag_mem(struct net *net);
 479 int ip_frag_nqueues(struct net *net);
 480
 481 /*
 482  *      Functions provided by ip_forward.c
 483  */
 484
 485 int ip_forward(struct sk_buff *skb);
 486
 487 /*
 488  *      Functions provided by ip_options.c
 489  */
 490
 491 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 492                       __be32 daddr, struct rtable *rt, int is_frag);
 493 int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 494 void ip_options_fragment(struct sk_buff *skb);
 495 int ip_options_compile(struct net *net, struct ip_options *opt,
 496                        struct sk_buff *skb);
 497 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 498                    unsigned char *data, int optlen);
 499 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 500                              unsigned char __user *data, int optlen);
 501 void ip_options_undo(struct ip_options *opt);
 502 void ip_forward_options(struct sk_buff *skb);
 503 int ip_options_rcv_srr(struct sk_buff *skb);
 504
 505 /*
 506  *      Functions provided by ip_sockglue.c
 507  */
 508
 509 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 510 void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 511 int ip_cmsg_send(struct net *net, struct msghdr *msg,
 512                  struct ipcm_cookie *ipc, bool allow_ipv6);
 513 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 514                   unsigned int optlen);
 515 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 516                   int __user *optlen);
 517 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 518                          char __user *optval, unsigned int optlen);
 519 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 520                          char __user *optval, int __user *optlen);
 521 int ip_ra_control(struct sock *sk, unsigned char on,
 522                   void (*destructor)(struct sock *));
 523
 524 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 525 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 526                    u32 info, u8 *payload);
 527 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 528                     u32 info);
 529
 530 #ifdef CONFIG_PROC_FS
 531 int ip_misc_proc_init(void);
 532 #endif
 533
 534 #endif  /* _IP_H */