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 1 43 #define IPSKB_XFRM_TUNNEL_SIZE 2 44 #define IPSKB_XFRM_TRANSFORMED 4 45 #define IPSKB_FRAG_COMPLETE 8 46 #define IPSKB_REROUTED 16 47 48 u16 frag_max_size; 49 }; 50 51 static inline unsigned int ip_hdrlen(const struct sk_buff *skb) 52 { 53 return ip_hdr(skb)->ihl * 4; 54 } 55 56 struct ipcm_cookie { 57 __be32 addr; 58 int oif; 59 struct ip_options_rcu *opt; 60 __u8 tx_flags; 61 __u8 ttl; 62 __s16 tos; 63 char priority; 64 }; 65 66 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb)) 67 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb)) 68 69 struct ip_ra_chain { 70 struct ip_ra_chain __rcu *next; 71 struct sock *sk; 72 union { 73 void (*destructor)(struct sock *); 74 struct sock *saved_sk; 75 }; 76 struct rcu_head rcu; 77 }; 78 79 extern struct ip_ra_chain __rcu *ip_ra_chain; 80 81 /* IP flags. */ 82 #define IP_CE 0x8000 /* Flag: "Congestion" */ 83 #define IP_DF 0x4000 /* Flag: "Don't Fragment" */ 84 #define IP_MF 0x2000 /* Flag: "More Fragments" */ 85 #define IP_OFFSET 0x1FFF /* "Fragment Offset" part */ 86 87 #define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */ 88 89 struct msghdr; 90 struct net_device; 91 struct packet_type; 92 struct rtable; 93 struct sockaddr; 94 95 int igmp_mc_init(void); 96 97 /* 98 * Functions provided by ip.c 99 */ 100 101 int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, 102 __be32 saddr, __be32 daddr, 103 struct ip_options_rcu *opt); 104 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, 105 struct net_device *orig_dev); 106 int ip_local_deliver(struct sk_buff *skb); 107 int ip_mr_input(struct sk_buff *skb); 108 int ip_output(struct sock *sk, struct sk_buff *skb); 109 int ip_mc_output(struct sock *sk, struct sk_buff *skb); 110 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)); 111 int ip_do_nat(struct sk_buff *skb); 112 void ip_send_check(struct iphdr *ip); 113 int __ip_local_out(struct sk_buff *skb); 114 int ip_local_out_sk(struct sock *sk, struct sk_buff *skb); 115 static inline int ip_local_out(struct sk_buff *skb) 116 { 117 return ip_local_out_sk(skb->sk, skb); 118 } 119 120 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl); 121 void ip_init(void); 122 int ip_append_data(struct sock *sk, struct flowi4 *fl4, 123 int getfrag(void *from, char *to, int offset, int len, 124 int odd, struct sk_buff *skb), 125 void *from, int len, int protolen, 126 struct ipcm_cookie *ipc, 127 struct rtable **rt, 128 unsigned int flags); 129 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, 130 struct sk_buff *skb); 131 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, 132 int offset, size_t size, int flags); 133 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4, 134 struct sk_buff_head *queue, 135 struct inet_cork *cork); 136 int ip_send_skb(struct net *net, struct sk_buff *skb); 137 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4); 138 void ip_flush_pending_frames(struct sock *sk); 139 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4, 140 int getfrag(void *from, char *to, int offset, 141 int len, int odd, struct sk_buff *skb), 142 void *from, int length, int transhdrlen, 143 struct ipcm_cookie *ipc, struct rtable **rtp, 144 unsigned int flags); 145 146 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4) 147 { 148 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base); 149 } 150 151 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet) 152 { 153 return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos); 154 } 155 156 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk) 157 { 158 return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk); 159 } 160 161 /* datagram.c */ 162 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 163 164 void ip4_datagram_release_cb(struct sock *sk); 165 166 struct ip_reply_arg { 167 struct kvec iov[1]; 168 int flags; 169 __wsum csum; 170 int csumoffset; /* u16 offset of csum in iov[0].iov_base */ 171 /* -1 if not needed */ 172 int bound_dev_if; 173 u8 tos; 174 }; 175 176 #define IP_REPLY_ARG_NOSRCCHECK 1 177 178 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg) 179 { 180 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0; 181 } 182 183 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, 184 const struct ip_options *sopt, 185 __be32 daddr, __be32 saddr, 186 const struct ip_reply_arg *arg, 187 unsigned int len); 188 189 #define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field) 190 #define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field) 191 #define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val) 192 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val) 193 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val) 194 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val) 195 #define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field) 196 #define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field) 197 #define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field) 198 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd) 199 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd) 200 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd) 201 202 unsigned long snmp_fold_field(void __percpu *mib, int offt); 203 #if BITS_PER_LONG==32 204 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off); 205 #else 206 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off) 207 { 208 return snmp_fold_field(mib, offt); 209 } 210 #endif 211 212 void inet_get_local_port_range(struct net *net, int *low, int *high); 213 214 #ifdef CONFIG_SYSCTL 215 static inline int inet_is_local_reserved_port(struct net *net, int port) 216 { 217 if (!net->ipv4.sysctl_local_reserved_ports) 218 return 0; 219 return test_bit(port, net->ipv4.sysctl_local_reserved_ports); 220 } 221 222 static inline bool sysctl_dev_name_is_allowed(const char *name) 223 { 224 return strcmp(name, "default") != 0 && strcmp(name, "all") != 0; 225 } 226 227 #else 228 static inline int inet_is_local_reserved_port(struct net *net, int port) 229 { 230 return 0; 231 } 232 #endif 233 234 /* From inetpeer.c */ 235 extern int inet_peer_threshold; 236 extern int inet_peer_minttl; 237 extern int inet_peer_maxttl; 238 239 /* From ip_input.c */ 240 extern int sysctl_ip_early_demux; 241 242 /* From ip_output.c */ 243 extern int sysctl_ip_dynaddr; 244 245 void ipfrag_init(void); 246 247 void ip_static_sysctl_init(void); 248 249 #define IP4_REPLY_MARK(net, mark) \ 250 ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0) 251 252 static inline bool ip_is_fragment(const struct iphdr *iph) 253 { 254 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0; 255 } 256 257 #ifdef CONFIG_INET 258 #include <net/dst.h> 259 260 /* The function in 2.2 was invalid, producing wrong result for 261 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */ 262 static inline 263 int ip_decrease_ttl(struct iphdr *iph) 264 { 265 u32 check = (__force u32)iph->check; 266 check += (__force u32)htons(0x0100); 267 iph->check = (__force __sum16)(check + (check>=0xFFFF)); 268 return --iph->ttl; 269 } 270 271 static inline 272 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst) 273 { 274 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO || 275 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT && 276 !(dst_metric_locked(dst, RTAX_MTU))); 277 } 278 279 static inline bool ip_sk_accept_pmtu(const struct sock *sk) 280 { 281 return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE && 282 inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT; 283 } 284 285 static inline bool ip_sk_use_pmtu(const struct sock *sk) 286 { 287 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE; 288 } 289 290 static inline bool ip_sk_ignore_df(const struct sock *sk) 291 { 292 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO || 293 inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT; 294 } 295 296 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, 297 bool forwarding) 298 { 299 struct net *net = dev_net(dst->dev); 300 301 if (net->ipv4.sysctl_ip_fwd_use_pmtu || 302 dst_metric_locked(dst, RTAX_MTU) || 303 !forwarding) 304 return dst_mtu(dst); 305 306 return min(dst->dev->mtu, IP_MAX_MTU); 307 } 308 309 static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb) 310 { 311 if (!skb->sk || ip_sk_use_pmtu(skb->sk)) { 312 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED; 313 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding); 314 } else { 315 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU); 316 } 317 } 318 319 u32 ip_idents_reserve(u32 hash, int segs); 320 void __ip_select_ident(struct iphdr *iph, int segs); 321 322 static inline void ip_select_ident_segs(struct sk_buff *skb, struct sock *sk, int segs) 323 { 324 struct iphdr *iph = ip_hdr(skb); 325 326 if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) { 327 /* This is only to work around buggy Windows95/2000 328 * VJ compression implementations. If the ID field 329 * does not change, they drop every other packet in 330 * a TCP stream using header compression. 331 */ 332 if (sk && inet_sk(sk)->inet_daddr) { 333 iph->id = htons(inet_sk(sk)->inet_id); 334 inet_sk(sk)->inet_id += segs; 335 } else { 336 iph->id = 0; 337 } 338 } else { 339 __ip_select_ident(iph, segs); 340 } 341 } 342 343 static inline void ip_select_ident(struct sk_buff *skb, struct sock *sk) 344 { 345 ip_select_ident_segs(skb, sk, 1); 346 } 347 348 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto) 349 { 350 return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 351 skb->len, proto, 0); 352 } 353 354 static inline void inet_set_txhash(struct sock *sk) 355 { 356 struct inet_sock *inet = inet_sk(sk); 357 struct flow_keys keys; 358 359 keys.src = inet->inet_saddr; 360 keys.dst = inet->inet_daddr; 361 keys.port16[0] = inet->inet_sport; 362 keys.port16[1] = inet->inet_dport; 363 364 sk->sk_txhash = flow_hash_from_keys(&keys); 365 } 366 367 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto) 368 { 369 const struct iphdr *iph = skb_gro_network_header(skb); 370 371 return csum_tcpudp_nofold(iph->saddr, iph->daddr, 372 skb_gro_len(skb), proto, 0); 373 } 374 375 /* 376 * Map a multicast IP onto multicast MAC for type ethernet. 377 */ 378 379 static inline void ip_eth_mc_map(__be32 naddr, char *buf) 380 { 381 __u32 addr=ntohl(naddr); 382 buf[0]=0x01; 383 buf[1]=0x00; 384 buf[2]=0x5e; 385 buf[5]=addr&0xFF; 386 addr>>=8; 387 buf[4]=addr&0xFF; 388 addr>>=8; 389 buf[3]=addr&0x7F; 390 } 391 392 /* 393 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand. 394 * Leave P_Key as 0 to be filled in by driver. 395 */ 396 397 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 398 { 399 __u32 addr; 400 unsigned char scope = broadcast[5] & 0xF; 401 402 buf[0] = 0; /* Reserved */ 403 buf[1] = 0xff; /* Multicast QPN */ 404 buf[2] = 0xff; 405 buf[3] = 0xff; 406 addr = ntohl(naddr); 407 buf[4] = 0xff; 408 buf[5] = 0x10 | scope; /* scope from broadcast address */ 409 buf[6] = 0x40; /* IPv4 signature */ 410 buf[7] = 0x1b; 411 buf[8] = broadcast[8]; /* P_Key */ 412 buf[9] = broadcast[9]; 413 buf[10] = 0; 414 buf[11] = 0; 415 buf[12] = 0; 416 buf[13] = 0; 417 buf[14] = 0; 418 buf[15] = 0; 419 buf[19] = addr & 0xff; 420 addr >>= 8; 421 buf[18] = addr & 0xff; 422 addr >>= 8; 423 buf[17] = addr & 0xff; 424 addr >>= 8; 425 buf[16] = addr & 0x0f; 426 } 427 428 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 429 { 430 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0) 431 memcpy(buf, broadcast, 4); 432 else 433 memcpy(buf, &naddr, sizeof(naddr)); 434 } 435 436 #if IS_ENABLED(CONFIG_IPV6) 437 #include <linux/ipv6.h> 438 #endif 439 440 static __inline__ void inet_reset_saddr(struct sock *sk) 441 { 442 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0; 443 #if IS_ENABLED(CONFIG_IPV6) 444 if (sk->sk_family == PF_INET6) { 445 struct ipv6_pinfo *np = inet6_sk(sk); 446 447 memset(&np->saddr, 0, sizeof(np->saddr)); 448 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr)); 449 } 450 #endif 451 } 452 453 #endif 454 455 static inline int sk_mc_loop(struct sock *sk) 456 { 457 if (!sk) 458 return 1; 459 switch (sk->sk_family) { 460 case AF_INET: 461 return inet_sk(sk)->mc_loop; 462 #if IS_ENABLED(CONFIG_IPV6) 463 case AF_INET6: 464 return inet6_sk(sk)->mc_loop; 465 #endif 466 } 467 WARN_ON(1); 468 return 1; 469 } 470 471 bool ip_call_ra_chain(struct sk_buff *skb); 472 473 /* 474 * Functions provided by ip_fragment.c 475 */ 476 477 enum ip_defrag_users { 478 IP_DEFRAG_LOCAL_DELIVER, 479 IP_DEFRAG_CALL_RA_CHAIN, 480 IP_DEFRAG_CONNTRACK_IN, 481 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX, 482 IP_DEFRAG_CONNTRACK_OUT, 483 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX, 484 IP_DEFRAG_CONNTRACK_BRIDGE_IN, 485 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX, 486 IP_DEFRAG_VS_IN, 487 IP_DEFRAG_VS_OUT, 488 IP_DEFRAG_VS_FWD, 489 IP_DEFRAG_AF_PACKET, 490 IP_DEFRAG_MACVLAN, 491 }; 492 493 int ip_defrag(struct sk_buff *skb, u32 user); 494 #ifdef CONFIG_INET 495 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user); 496 #else 497 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 498 { 499 return skb; 500 } 501 #endif 502 int ip_frag_mem(struct net *net); 503 504 /* 505 * Functions provided by ip_forward.c 506 */ 507 508 int ip_forward(struct sk_buff *skb); 509 510 /* 511 * Functions provided by ip_options.c 512 */ 513 514 void ip_options_build(struct sk_buff *skb, struct ip_options *opt, 515 __be32 daddr, struct rtable *rt, int is_frag); 516 517 int __ip_options_echo(struct ip_options *dopt, struct sk_buff *skb, 518 const struct ip_options *sopt); 519 static inline int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb) 520 { 521 return __ip_options_echo(dopt, skb, &IPCB(skb)->opt); 522 } 523 524 void ip_options_fragment(struct sk_buff *skb); 525 int ip_options_compile(struct net *net, struct ip_options *opt, 526 struct sk_buff *skb); 527 int ip_options_get(struct net *net, struct ip_options_rcu **optp, 528 unsigned char *data, int optlen); 529 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, 530 unsigned char __user *data, int optlen); 531 void ip_options_undo(struct ip_options *opt); 532 void ip_forward_options(struct sk_buff *skb); 533 int ip_options_rcv_srr(struct sk_buff *skb); 534 535 /* 536 * Functions provided by ip_sockglue.c 537 */ 538 539 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb); 540 void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb); 541 int ip_cmsg_send(struct net *net, struct msghdr *msg, 542 struct ipcm_cookie *ipc, bool allow_ipv6); 543 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 544 unsigned int optlen); 545 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 546 int __user *optlen); 547 int compat_ip_setsockopt(struct sock *sk, int level, int optname, 548 char __user *optval, unsigned int optlen); 549 int compat_ip_getsockopt(struct sock *sk, int level, int optname, 550 char __user *optval, int __user *optlen); 551 int ip_ra_control(struct sock *sk, unsigned char on, 552 void (*destructor)(struct sock *)); 553 554 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len); 555 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port, 556 u32 info, u8 *payload); 557 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport, 558 u32 info); 559 560 bool icmp_global_allow(void); 561 extern int sysctl_icmp_msgs_per_sec; 562 extern int sysctl_icmp_msgs_burst; 563 564 #ifdef CONFIG_PROC_FS 565 int ip_misc_proc_init(void); 566 #endif 567 568 #endif /* _IP_H */ 569