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