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 sk_buff *skb, int (*output)(struct sk_buff *)); 112 int ip_do_nat(struct sk_buff *skb); 113 void ip_send_check(struct iphdr *ip); 114 int __ip_local_out(struct sk_buff *skb); 115 int ip_local_out_sk(struct sock *sk, struct sk_buff *skb); 116 static inline int ip_local_out(struct sk_buff *skb) 117 { 118 return ip_local_out_sk(skb->sk, skb); 119 } 120 121 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl); 122 void ip_init(void); 123 int ip_append_data(struct sock *sk, struct flowi4 *fl4, 124 int getfrag(void *from, char *to, int offset, int len, 125 int odd, struct sk_buff *skb), 126 void *from, int len, int protolen, 127 struct ipcm_cookie *ipc, 128 struct rtable **rt, 129 unsigned int flags); 130 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, 131 struct sk_buff *skb); 132 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, 133 int offset, size_t size, int flags); 134 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4, 135 struct sk_buff_head *queue, 136 struct inet_cork *cork); 137 int ip_send_skb(struct net *net, struct sk_buff *skb); 138 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4); 139 void ip_flush_pending_frames(struct sock *sk); 140 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4, 141 int getfrag(void *from, char *to, int offset, 142 int len, int odd, struct sk_buff *skb), 143 void *from, int length, int transhdrlen, 144 struct ipcm_cookie *ipc, struct rtable **rtp, 145 unsigned int flags); 146 147 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4) 148 { 149 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base); 150 } 151 152 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet) 153 { 154 return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos); 155 } 156 157 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk) 158 { 159 return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk); 160 } 161 162 /* datagram.c */ 163 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 164 165 void ip4_datagram_release_cb(struct sock *sk); 166 167 struct ip_reply_arg { 168 struct kvec iov[1]; 169 int flags; 170 __wsum csum; 171 int csumoffset; /* u16 offset of csum in iov[0].iov_base */ 172 /* -1 if not needed */ 173 int bound_dev_if; 174 u8 tos; 175 }; 176 177 #define IP_REPLY_ARG_NOSRCCHECK 1 178 179 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg) 180 { 181 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0; 182 } 183 184 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, 185 const struct ip_options *sopt, 186 __be32 daddr, __be32 saddr, 187 const struct ip_reply_arg *arg, 188 unsigned int len); 189 190 #define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field) 191 #define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field) 192 #define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val) 193 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val) 194 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val) 195 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val) 196 #define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field) 197 #define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field) 198 #define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field) 199 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd) 200 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd) 201 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd) 202 203 unsigned long snmp_fold_field(void __percpu *mib, int offt); 204 #if BITS_PER_LONG==32 205 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off); 206 #else 207 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off) 208 { 209 return snmp_fold_field(mib, offt); 210 } 211 #endif 212 213 void inet_get_local_port_range(struct net *net, int *low, int *high); 214 215 #ifdef CONFIG_SYSCTL 216 static inline int inet_is_local_reserved_port(struct net *net, int port) 217 { 218 if (!net->ipv4.sysctl_local_reserved_ports) 219 return 0; 220 return test_bit(port, net->ipv4.sysctl_local_reserved_ports); 221 } 222 223 static inline bool sysctl_dev_name_is_allowed(const char *name) 224 { 225 return strcmp(name, "default") != 0 && strcmp(name, "all") != 0; 226 } 227 228 #else 229 static inline int inet_is_local_reserved_port(struct net *net, int port) 230 { 231 return 0; 232 } 233 #endif 234 235 /* From inetpeer.c */ 236 extern int inet_peer_threshold; 237 extern int inet_peer_minttl; 238 extern int inet_peer_maxttl; 239 240 /* From ip_input.c */ 241 extern int sysctl_ip_early_demux; 242 243 /* From ip_output.c */ 244 extern int sysctl_ip_dynaddr; 245 246 void ipfrag_init(void); 247 248 void ip_static_sysctl_init(void); 249 250 #define IP4_REPLY_MARK(net, mark) \ 251 ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0) 252 253 static inline bool ip_is_fragment(const struct iphdr *iph) 254 { 255 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0; 256 } 257 258 #ifdef CONFIG_INET 259 #include <net/dst.h> 260 261 /* The function in 2.2 was invalid, producing wrong result for 262 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */ 263 static inline 264 int ip_decrease_ttl(struct iphdr *iph) 265 { 266 u32 check = (__force u32)iph->check; 267 check += (__force u32)htons(0x0100); 268 iph->check = (__force __sum16)(check + (check>=0xFFFF)); 269 return --iph->ttl; 270 } 271 272 static inline 273 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst) 274 { 275 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO || 276 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT && 277 !(dst_metric_locked(dst, RTAX_MTU))); 278 } 279 280 static inline bool ip_sk_accept_pmtu(const struct sock *sk) 281 { 282 return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE && 283 inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT; 284 } 285 286 static inline bool ip_sk_use_pmtu(const struct sock *sk) 287 { 288 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE; 289 } 290 291 static inline bool ip_sk_ignore_df(const struct sock *sk) 292 { 293 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO || 294 inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT; 295 } 296 297 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, 298 bool forwarding) 299 { 300 struct net *net = dev_net(dst->dev); 301 302 if (net->ipv4.sysctl_ip_fwd_use_pmtu || 303 dst_metric_locked(dst, RTAX_MTU) || 304 !forwarding) 305 return dst_mtu(dst); 306 307 return min(dst->dev->mtu, IP_MAX_MTU); 308 } 309 310 static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb) 311 { 312 if (!skb->sk || ip_sk_use_pmtu(skb->sk)) { 313 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED; 314 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding); 315 } else { 316 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU); 317 } 318 } 319 320 u32 ip_idents_reserve(u32 hash, int segs); 321 void __ip_select_ident(struct iphdr *iph, int segs); 322 323 static inline void ip_select_ident_segs(struct sk_buff *skb, struct sock *sk, int segs) 324 { 325 struct iphdr *iph = ip_hdr(skb); 326 327 if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) { 328 /* This is only to work around buggy Windows95/2000 329 * VJ compression implementations. If the ID field 330 * does not change, they drop every other packet in 331 * a TCP stream using header compression. 332 */ 333 if (sk && inet_sk(sk)->inet_daddr) { 334 iph->id = htons(inet_sk(sk)->inet_id); 335 inet_sk(sk)->inet_id += segs; 336 } else { 337 iph->id = 0; 338 } 339 } else { 340 __ip_select_ident(iph, segs); 341 } 342 } 343 344 static inline void ip_select_ident(struct sk_buff *skb, struct sock *sk) 345 { 346 ip_select_ident_segs(skb, sk, 1); 347 } 348 349 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto) 350 { 351 return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 352 skb->len, proto, 0); 353 } 354 355 static inline void inet_set_txhash(struct sock *sk) 356 { 357 struct inet_sock *inet = inet_sk(sk); 358 struct flow_keys keys; 359 360 keys.src = inet->inet_saddr; 361 keys.dst = inet->inet_daddr; 362 keys.port16[0] = inet->inet_sport; 363 keys.port16[1] = inet->inet_dport; 364 365 sk->sk_txhash = flow_hash_from_keys(&keys); 366 } 367 368 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto) 369 { 370 const struct iphdr *iph = skb_gro_network_header(skb); 371 372 return csum_tcpudp_nofold(iph->saddr, iph->daddr, 373 skb_gro_len(skb), proto, 0); 374 } 375 376 /* 377 * Map a multicast IP onto multicast MAC for type ethernet. 378 */ 379 380 static inline void ip_eth_mc_map(__be32 naddr, char *buf) 381 { 382 __u32 addr=ntohl(naddr); 383 buf[0]=0x01; 384 buf[1]=0x00; 385 buf[2]=0x5e; 386 buf[5]=addr&0xFF; 387 addr>>=8; 388 buf[4]=addr&0xFF; 389 addr>>=8; 390 buf[3]=addr&0x7F; 391 } 392 393 /* 394 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand. 395 * Leave P_Key as 0 to be filled in by driver. 396 */ 397 398 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 399 { 400 __u32 addr; 401 unsigned char scope = broadcast[5] & 0xF; 402 403 buf[0] = 0; /* Reserved */ 404 buf[1] = 0xff; /* Multicast QPN */ 405 buf[2] = 0xff; 406 buf[3] = 0xff; 407 addr = ntohl(naddr); 408 buf[4] = 0xff; 409 buf[5] = 0x10 | scope; /* scope from broadcast address */ 410 buf[6] = 0x40; /* IPv4 signature */ 411 buf[7] = 0x1b; 412 buf[8] = broadcast[8]; /* P_Key */ 413 buf[9] = broadcast[9]; 414 buf[10] = 0; 415 buf[11] = 0; 416 buf[12] = 0; 417 buf[13] = 0; 418 buf[14] = 0; 419 buf[15] = 0; 420 buf[19] = addr & 0xff; 421 addr >>= 8; 422 buf[18] = addr & 0xff; 423 addr >>= 8; 424 buf[17] = addr & 0xff; 425 addr >>= 8; 426 buf[16] = addr & 0x0f; 427 } 428 429 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 430 { 431 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0) 432 memcpy(buf, broadcast, 4); 433 else 434 memcpy(buf, &naddr, sizeof(naddr)); 435 } 436 437 #if IS_ENABLED(CONFIG_IPV6) 438 #include <linux/ipv6.h> 439 #endif 440 441 static __inline__ void inet_reset_saddr(struct sock *sk) 442 { 443 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0; 444 #if IS_ENABLED(CONFIG_IPV6) 445 if (sk->sk_family == PF_INET6) { 446 struct ipv6_pinfo *np = inet6_sk(sk); 447 448 memset(&np->saddr, 0, sizeof(np->saddr)); 449 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr)); 450 } 451 #endif 452 } 453 454 #endif 455 456 static inline int sk_mc_loop(struct sock *sk) 457 { 458 if (!sk) 459 return 1; 460 switch (sk->sk_family) { 461 case AF_INET: 462 return inet_sk(sk)->mc_loop; 463 #if IS_ENABLED(CONFIG_IPV6) 464 case AF_INET6: 465 return inet6_sk(sk)->mc_loop; 466 #endif 467 } 468 WARN_ON(1); 469 return 1; 470 } 471 472 bool ip_call_ra_chain(struct sk_buff *skb); 473 474 /* 475 * Functions provided by ip_fragment.c 476 */ 477 478 enum ip_defrag_users { 479 IP_DEFRAG_LOCAL_DELIVER, 480 IP_DEFRAG_CALL_RA_CHAIN, 481 IP_DEFRAG_CONNTRACK_IN, 482 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX, 483 IP_DEFRAG_CONNTRACK_OUT, 484 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX, 485 IP_DEFRAG_CONNTRACK_BRIDGE_IN, 486 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX, 487 IP_DEFRAG_VS_IN, 488 IP_DEFRAG_VS_OUT, 489 IP_DEFRAG_VS_FWD, 490 IP_DEFRAG_AF_PACKET, 491 IP_DEFRAG_MACVLAN, 492 }; 493 494 int ip_defrag(struct sk_buff *skb, u32 user); 495 #ifdef CONFIG_INET 496 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user); 497 #else 498 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 499 { 500 return skb; 501 } 502 #endif 503 int ip_frag_mem(struct net *net); 504 505 /* 506 * Functions provided by ip_forward.c 507 */ 508 509 int ip_forward(struct sk_buff *skb); 510 511 /* 512 * Functions provided by ip_options.c 513 */ 514 515 void ip_options_build(struct sk_buff *skb, struct ip_options *opt, 516 __be32 daddr, struct rtable *rt, int is_frag); 517 518 int __ip_options_echo(struct ip_options *dopt, struct sk_buff *skb, 519 const struct ip_options *sopt); 520 static inline int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb) 521 { 522 return __ip_options_echo(dopt, skb, &IPCB(skb)->opt); 523 } 524 525 void ip_options_fragment(struct sk_buff *skb); 526 int ip_options_compile(struct net *net, struct ip_options *opt, 527 struct sk_buff *skb); 528 int ip_options_get(struct net *net, struct ip_options_rcu **optp, 529 unsigned char *data, int optlen); 530 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, 531 unsigned char __user *data, int optlen); 532 void ip_options_undo(struct ip_options *opt); 533 void ip_forward_options(struct sk_buff *skb); 534 int ip_options_rcv_srr(struct sk_buff *skb); 535 536 /* 537 * Functions provided by ip_sockglue.c 538 */ 539 540 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb); 541 void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb, int offset); 542 int ip_cmsg_send(struct net *net, struct msghdr *msg, 543 struct ipcm_cookie *ipc, bool allow_ipv6); 544 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 545 unsigned int optlen); 546 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 547 int __user *optlen); 548 int compat_ip_setsockopt(struct sock *sk, int level, int optname, 549 char __user *optval, unsigned int optlen); 550 int compat_ip_getsockopt(struct sock *sk, int level, int optname, 551 char __user *optval, int __user *optlen); 552 int ip_ra_control(struct sock *sk, unsigned char on, 553 void (*destructor)(struct sock *)); 554 555 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len); 556 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port, 557 u32 info, u8 *payload); 558 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport, 559 u32 info); 560 561 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb) 562 { 563 ip_cmsg_recv_offset(msg, skb, 0); 564 } 565 566 bool icmp_global_allow(void); 567 extern int sysctl_icmp_msgs_per_sec; 568 extern int sysctl_icmp_msgs_burst; 569 570 #ifdef CONFIG_PROC_FS 571 int ip_misc_proc_init(void); 572 #endif 573 574 #endif /* _IP_H */ 575