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 208 209 void inet_get_local_port_range(struct net *net, int *low, int *high); 210 211 #ifdef CONFIG_SYSCTL 212 static inline int inet_is_local_reserved_port(struct net *net, int port) 213 { 214 if (!net->ipv4.sysctl_local_reserved_ports) 215 return 0; 216 return test_bit(port, net->ipv4.sysctl_local_reserved_ports); 217 } 218 #else 219 static inline int inet_is_local_reserved_port(struct net *net, int port) 220 { 221 return 0; 222 } 223 #endif 224 225 extern int sysctl_ip_nonlocal_bind; 226 227 /* From inetpeer.c */ 228 extern int inet_peer_threshold; 229 extern int inet_peer_minttl; 230 extern int inet_peer_maxttl; 231 232 /* From ip_input.c */ 233 extern int sysctl_ip_early_demux; 234 235 /* From ip_output.c */ 236 extern int sysctl_ip_dynaddr; 237 238 void ipfrag_init(void); 239 240 void ip_static_sysctl_init(void); 241 242 #define IP4_REPLY_MARK(net, mark) \ 243 ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0) 244 245 static inline bool ip_is_fragment(const struct iphdr *iph) 246 { 247 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0; 248 } 249 250 #ifdef CONFIG_INET 251 #include <net/dst.h> 252 253 /* The function in 2.2 was invalid, producing wrong result for 254 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */ 255 static inline 256 int ip_decrease_ttl(struct iphdr *iph) 257 { 258 u32 check = (__force u32)iph->check; 259 check += (__force u32)htons(0x0100); 260 iph->check = (__force __sum16)(check + (check>=0xFFFF)); 261 return --iph->ttl; 262 } 263 264 static inline 265 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst) 266 { 267 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO || 268 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT && 269 !(dst_metric_locked(dst, RTAX_MTU))); 270 } 271 272 static inline bool ip_sk_accept_pmtu(const struct sock *sk) 273 { 274 return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE && 275 inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT; 276 } 277 278 static inline bool ip_sk_use_pmtu(const struct sock *sk) 279 { 280 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE; 281 } 282 283 static inline bool ip_sk_ignore_df(const struct sock *sk) 284 { 285 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO || 286 inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT; 287 } 288 289 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, 290 bool forwarding) 291 { 292 struct net *net = dev_net(dst->dev); 293 294 if (net->ipv4.sysctl_ip_fwd_use_pmtu || 295 dst_metric_locked(dst, RTAX_MTU) || 296 !forwarding) 297 return dst_mtu(dst); 298 299 return min(dst->dev->mtu, IP_MAX_MTU); 300 } 301 302 static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb) 303 { 304 if (!skb->sk || ip_sk_use_pmtu(skb->sk)) { 305 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED; 306 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding); 307 } else { 308 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU); 309 } 310 } 311 312 #define IP_IDENTS_SZ 2048u 313 extern atomic_t *ip_idents; 314 315 static inline u32 ip_idents_reserve(u32 hash, int segs) 316 { 317 atomic_t *id_ptr = ip_idents + hash % IP_IDENTS_SZ; 318 319 return atomic_add_return(segs, id_ptr) - segs; 320 } 321 322 void __ip_select_ident(struct iphdr *iph, int segs); 323 324 static inline void ip_select_ident_segs(struct sk_buff *skb, struct sock *sk, int segs) 325 { 326 struct iphdr *iph = ip_hdr(skb); 327 328 if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) { 329 /* This is only to work around buggy Windows95/2000 330 * VJ compression implementations. If the ID field 331 * does not change, they drop every other packet in 332 * a TCP stream using header compression. 333 */ 334 if (sk && inet_sk(sk)->inet_daddr) { 335 iph->id = htons(inet_sk(sk)->inet_id); 336 inet_sk(sk)->inet_id += segs; 337 } else { 338 iph->id = 0; 339 } 340 } else { 341 __ip_select_ident(iph, segs); 342 } 343 } 344 345 static inline void ip_select_ident(struct sk_buff *skb, struct sock *sk) 346 { 347 ip_select_ident_segs(skb, sk, 1); 348 } 349 350 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto) 351 { 352 return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 353 skb->len, proto, 0); 354 } 355 356 /* 357 * Map a multicast IP onto multicast MAC for type ethernet. 358 */ 359 360 static inline void ip_eth_mc_map(__be32 naddr, char *buf) 361 { 362 __u32 addr=ntohl(naddr); 363 buf[0]=0x01; 364 buf[1]=0x00; 365 buf[2]=0x5e; 366 buf[5]=addr&0xFF; 367 addr>>=8; 368 buf[4]=addr&0xFF; 369 addr>>=8; 370 buf[3]=addr&0x7F; 371 } 372 373 /* 374 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand. 375 * Leave P_Key as 0 to be filled in by driver. 376 */ 377 378 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 379 { 380 __u32 addr; 381 unsigned char scope = broadcast[5] & 0xF; 382 383 buf[0] = 0; /* Reserved */ 384 buf[1] = 0xff; /* Multicast QPN */ 385 buf[2] = 0xff; 386 buf[3] = 0xff; 387 addr = ntohl(naddr); 388 buf[4] = 0xff; 389 buf[5] = 0x10 | scope; /* scope from broadcast address */ 390 buf[6] = 0x40; /* IPv4 signature */ 391 buf[7] = 0x1b; 392 buf[8] = broadcast[8]; /* P_Key */ 393 buf[9] = broadcast[9]; 394 buf[10] = 0; 395 buf[11] = 0; 396 buf[12] = 0; 397 buf[13] = 0; 398 buf[14] = 0; 399 buf[15] = 0; 400 buf[19] = addr & 0xff; 401 addr >>= 8; 402 buf[18] = addr & 0xff; 403 addr >>= 8; 404 buf[17] = addr & 0xff; 405 addr >>= 8; 406 buf[16] = addr & 0x0f; 407 } 408 409 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 410 { 411 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0) 412 memcpy(buf, broadcast, 4); 413 else 414 memcpy(buf, &naddr, sizeof(naddr)); 415 } 416 417 #if IS_ENABLED(CONFIG_IPV6) 418 #include <linux/ipv6.h> 419 #endif 420 421 static __inline__ void inet_reset_saddr(struct sock *sk) 422 { 423 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0; 424 #if IS_ENABLED(CONFIG_IPV6) 425 if (sk->sk_family == PF_INET6) { 426 struct ipv6_pinfo *np = inet6_sk(sk); 427 428 memset(&np->saddr, 0, sizeof(np->saddr)); 429 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr)); 430 } 431 #endif 432 } 433 434 #endif 435 436 static inline int sk_mc_loop(struct sock *sk) 437 { 438 if (!sk) 439 return 1; 440 switch (sk->sk_family) { 441 case AF_INET: 442 return inet_sk(sk)->mc_loop; 443 #if IS_ENABLED(CONFIG_IPV6) 444 case AF_INET6: 445 return inet6_sk(sk)->mc_loop; 446 #endif 447 } 448 WARN_ON(1); 449 return 1; 450 } 451 452 bool ip_call_ra_chain(struct sk_buff *skb); 453 454 /* 455 * Functions provided by ip_fragment.c 456 */ 457 458 enum ip_defrag_users { 459 IP_DEFRAG_LOCAL_DELIVER, 460 IP_DEFRAG_CALL_RA_CHAIN, 461 IP_DEFRAG_CONNTRACK_IN, 462 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX, 463 IP_DEFRAG_CONNTRACK_OUT, 464 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX, 465 IP_DEFRAG_CONNTRACK_BRIDGE_IN, 466 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX, 467 IP_DEFRAG_VS_IN, 468 IP_DEFRAG_VS_OUT, 469 IP_DEFRAG_VS_FWD, 470 IP_DEFRAG_AF_PACKET, 471 IP_DEFRAG_MACVLAN, 472 }; 473 474 int ip_defrag(struct sk_buff *skb, u32 user); 475 #ifdef CONFIG_INET 476 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user); 477 #else 478 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 479 { 480 return skb; 481 } 482 #endif 483 int ip_frag_mem(struct net *net); 484 int ip_frag_nqueues(struct net *net); 485 486 /* 487 * Functions provided by ip_forward.c 488 */ 489 490 int ip_forward(struct sk_buff *skb); 491 492 /* 493 * Functions provided by ip_options.c 494 */ 495 496 void ip_options_build(struct sk_buff *skb, struct ip_options *opt, 497 __be32 daddr, struct rtable *rt, int is_frag); 498 int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb); 499 void ip_options_fragment(struct sk_buff *skb); 500 int ip_options_compile(struct net *net, struct ip_options *opt, 501 struct sk_buff *skb); 502 int ip_options_get(struct net *net, struct ip_options_rcu **optp, 503 unsigned char *data, int optlen); 504 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, 505 unsigned char __user *data, int optlen); 506 void ip_options_undo(struct ip_options *opt); 507 void ip_forward_options(struct sk_buff *skb); 508 int ip_options_rcv_srr(struct sk_buff *skb); 509 510 /* 511 * Functions provided by ip_sockglue.c 512 */ 513 514 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb); 515 void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb); 516 int ip_cmsg_send(struct net *net, struct msghdr *msg, 517 struct ipcm_cookie *ipc, bool allow_ipv6); 518 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 519 unsigned int optlen); 520 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 521 int __user *optlen); 522 int compat_ip_setsockopt(struct sock *sk, int level, int optname, 523 char __user *optval, unsigned int optlen); 524 int compat_ip_getsockopt(struct sock *sk, int level, int optname, 525 char __user *optval, int __user *optlen); 526 int ip_ra_control(struct sock *sk, unsigned char on, 527 void (*destructor)(struct sock *)); 528 529 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len); 530 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port, 531 u32 info, u8 *payload); 532 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport, 533 u32 info); 534 535 #ifdef CONFIG_PROC_FS 536 int ip_misc_proc_init(void); 537 #endif 538 539 #endif /* _IP_H */ 540