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 sk_buff *skb); 108 int ip_mc_output(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(struct sk_buff *skb); 114 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl); 115 void ip_init(void); 116 int ip_append_data(struct sock *sk, struct flowi4 *fl4, 117 int getfrag(void *from, char *to, int offset, int len, 118 int odd, struct sk_buff *skb), 119 void *from, int len, int protolen, 120 struct ipcm_cookie *ipc, 121 struct rtable **rt, 122 unsigned int flags); 123 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, 124 struct sk_buff *skb); 125 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, 126 int offset, size_t size, int flags); 127 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4, 128 struct sk_buff_head *queue, 129 struct inet_cork *cork); 130 int ip_send_skb(struct net *net, struct sk_buff *skb); 131 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4); 132 void ip_flush_pending_frames(struct sock *sk); 133 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4, 134 int getfrag(void *from, char *to, int offset, 135 int len, int odd, struct sk_buff *skb), 136 void *from, int length, int transhdrlen, 137 struct ipcm_cookie *ipc, struct rtable **rtp, 138 unsigned int flags); 139 140 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4) 141 { 142 return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base); 143 } 144 145 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet) 146 { 147 return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos); 148 } 149 150 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk) 151 { 152 return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk); 153 } 154 155 /* datagram.c */ 156 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 157 158 void ip4_datagram_release_cb(struct sock *sk); 159 160 struct ip_reply_arg { 161 struct kvec iov[1]; 162 int flags; 163 __wsum csum; 164 int csumoffset; /* u16 offset of csum in iov[0].iov_base */ 165 /* -1 if not needed */ 166 int bound_dev_if; 167 u8 tos; 168 }; 169 170 #define IP_REPLY_ARG_NOSRCCHECK 1 171 172 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg) 173 { 174 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0; 175 } 176 177 void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, 178 __be32 saddr, const struct ip_reply_arg *arg, 179 unsigned int len); 180 181 #define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field) 182 #define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field) 183 #define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val) 184 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val) 185 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val) 186 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val) 187 #define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field) 188 #define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field) 189 #define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field) 190 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd) 191 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd) 192 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd) 193 194 unsigned long snmp_fold_field(void __percpu *mib[], int offt); 195 #if BITS_PER_LONG==32 196 u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off); 197 #else 198 static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off) 199 { 200 return snmp_fold_field(mib, offt); 201 } 202 #endif 203 int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align); 204 205 static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ]) 206 { 207 int i; 208 209 BUG_ON(ptr == NULL); 210 for (i = 0; i < SNMP_ARRAY_SZ; i++) { 211 free_percpu(ptr[i]); 212 ptr[i] = NULL; 213 } 214 } 215 216 void inet_get_local_port_range(struct net *net, int *low, int *high); 217 218 extern unsigned long *sysctl_local_reserved_ports; 219 static inline int inet_is_reserved_local_port(int port) 220 { 221 return test_bit(port, sysctl_local_reserved_ports); 222 } 223 224 extern int sysctl_ip_nonlocal_bind; 225 226 /* From inetpeer.c */ 227 extern int inet_peer_threshold; 228 extern int inet_peer_minttl; 229 extern int inet_peer_maxttl; 230 231 /* From ip_input.c */ 232 extern int sysctl_ip_early_demux; 233 234 /* From ip_output.c */ 235 extern int sysctl_ip_dynaddr; 236 237 void ipfrag_init(void); 238 239 void ip_static_sysctl_init(void); 240 241 static inline bool ip_is_fragment(const struct iphdr *iph) 242 { 243 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0; 244 } 245 246 #ifdef CONFIG_INET 247 #include <net/dst.h> 248 249 /* The function in 2.2 was invalid, producing wrong result for 250 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */ 251 static inline 252 int ip_decrease_ttl(struct iphdr *iph) 253 { 254 u32 check = (__force u32)iph->check; 255 check += (__force u32)htons(0x0100); 256 iph->check = (__force __sum16)(check + (check>=0xFFFF)); 257 return --iph->ttl; 258 } 259 260 static inline 261 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst) 262 { 263 return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO || 264 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT && 265 !(dst_metric_locked(dst, RTAX_MTU))); 266 } 267 268 static inline bool ip_sk_accept_pmtu(const struct sock *sk) 269 { 270 return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE && 271 inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT; 272 } 273 274 static inline bool ip_sk_use_pmtu(const struct sock *sk) 275 { 276 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE; 277 } 278 279 static inline bool ip_sk_local_df(const struct sock *sk) 280 { 281 return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO || 282 inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT; 283 } 284 285 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, 286 bool forwarding) 287 { 288 struct net *net = dev_net(dst->dev); 289 290 if (net->ipv4.sysctl_ip_fwd_use_pmtu || 291 dst_metric_locked(dst, RTAX_MTU) || 292 !forwarding) 293 return dst_mtu(dst); 294 295 return min(dst->dev->mtu, IP_MAX_MTU); 296 } 297 298 static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb) 299 { 300 if (!skb->sk || ip_sk_use_pmtu(skb->sk)) { 301 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED; 302 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding); 303 } else { 304 return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU); 305 } 306 } 307 308 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more); 309 310 static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk) 311 { 312 struct iphdr *iph = ip_hdr(skb); 313 314 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) { 315 /* This is only to work around buggy Windows95/2000 316 * VJ compression implementations. If the ID field 317 * does not change, they drop every other packet in 318 * a TCP stream using header compression. 319 */ 320 iph->id = (sk && inet_sk(sk)->inet_daddr) ? 321 htons(inet_sk(sk)->inet_id++) : 0; 322 } else 323 __ip_select_ident(iph, dst, 0); 324 } 325 326 static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more) 327 { 328 struct iphdr *iph = ip_hdr(skb); 329 330 if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) { 331 if (sk && inet_sk(sk)->inet_daddr) { 332 iph->id = htons(inet_sk(sk)->inet_id); 333 inet_sk(sk)->inet_id += 1 + more; 334 } else 335 iph->id = 0; 336 } else 337 __ip_select_ident(iph, dst, more); 338 } 339 340 /* 341 * Map a multicast IP onto multicast MAC for type ethernet. 342 */ 343 344 static inline void ip_eth_mc_map(__be32 naddr, char *buf) 345 { 346 __u32 addr=ntohl(naddr); 347 buf[0]=0x01; 348 buf[1]=0x00; 349 buf[2]=0x5e; 350 buf[5]=addr&0xFF; 351 addr>>=8; 352 buf[4]=addr&0xFF; 353 addr>>=8; 354 buf[3]=addr&0x7F; 355 } 356 357 /* 358 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand. 359 * Leave P_Key as 0 to be filled in by driver. 360 */ 361 362 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 363 { 364 __u32 addr; 365 unsigned char scope = broadcast[5] & 0xF; 366 367 buf[0] = 0; /* Reserved */ 368 buf[1] = 0xff; /* Multicast QPN */ 369 buf[2] = 0xff; 370 buf[3] = 0xff; 371 addr = ntohl(naddr); 372 buf[4] = 0xff; 373 buf[5] = 0x10 | scope; /* scope from broadcast address */ 374 buf[6] = 0x40; /* IPv4 signature */ 375 buf[7] = 0x1b; 376 buf[8] = broadcast[8]; /* P_Key */ 377 buf[9] = broadcast[9]; 378 buf[10] = 0; 379 buf[11] = 0; 380 buf[12] = 0; 381 buf[13] = 0; 382 buf[14] = 0; 383 buf[15] = 0; 384 buf[19] = addr & 0xff; 385 addr >>= 8; 386 buf[18] = addr & 0xff; 387 addr >>= 8; 388 buf[17] = addr & 0xff; 389 addr >>= 8; 390 buf[16] = addr & 0x0f; 391 } 392 393 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf) 394 { 395 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0) 396 memcpy(buf, broadcast, 4); 397 else 398 memcpy(buf, &naddr, sizeof(naddr)); 399 } 400 401 #if IS_ENABLED(CONFIG_IPV6) 402 #include <linux/ipv6.h> 403 #endif 404 405 static __inline__ void inet_reset_saddr(struct sock *sk) 406 { 407 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0; 408 #if IS_ENABLED(CONFIG_IPV6) 409 if (sk->sk_family == PF_INET6) { 410 struct ipv6_pinfo *np = inet6_sk(sk); 411 412 memset(&np->saddr, 0, sizeof(np->saddr)); 413 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr)); 414 } 415 #endif 416 } 417 418 #endif 419 420 static inline int sk_mc_loop(struct sock *sk) 421 { 422 if (!sk) 423 return 1; 424 switch (sk->sk_family) { 425 case AF_INET: 426 return inet_sk(sk)->mc_loop; 427 #if IS_ENABLED(CONFIG_IPV6) 428 case AF_INET6: 429 return inet6_sk(sk)->mc_loop; 430 #endif 431 } 432 WARN_ON(1); 433 return 1; 434 } 435 436 bool ip_call_ra_chain(struct sk_buff *skb); 437 438 /* 439 * Functions provided by ip_fragment.c 440 */ 441 442 enum ip_defrag_users { 443 IP_DEFRAG_LOCAL_DELIVER, 444 IP_DEFRAG_CALL_RA_CHAIN, 445 IP_DEFRAG_CONNTRACK_IN, 446 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX, 447 IP_DEFRAG_CONNTRACK_OUT, 448 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX, 449 IP_DEFRAG_CONNTRACK_BRIDGE_IN, 450 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX, 451 IP_DEFRAG_VS_IN, 452 IP_DEFRAG_VS_OUT, 453 IP_DEFRAG_VS_FWD, 454 IP_DEFRAG_AF_PACKET, 455 IP_DEFRAG_MACVLAN, 456 }; 457 458 int ip_defrag(struct sk_buff *skb, u32 user); 459 #ifdef CONFIG_INET 460 struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user); 461 #else 462 static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) 463 { 464 return skb; 465 } 466 #endif 467 int ip_frag_mem(struct net *net); 468 int ip_frag_nqueues(struct net *net); 469 470 /* 471 * Functions provided by ip_forward.c 472 */ 473 474 int ip_forward(struct sk_buff *skb); 475 476 /* 477 * Functions provided by ip_options.c 478 */ 479 480 void ip_options_build(struct sk_buff *skb, struct ip_options *opt, 481 __be32 daddr, struct rtable *rt, int is_frag); 482 int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb); 483 void ip_options_fragment(struct sk_buff *skb); 484 int ip_options_compile(struct net *net, struct ip_options *opt, 485 struct sk_buff *skb); 486 int ip_options_get(struct net *net, struct ip_options_rcu **optp, 487 unsigned char *data, int optlen); 488 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, 489 unsigned char __user *data, int optlen); 490 void ip_options_undo(struct ip_options *opt); 491 void ip_forward_options(struct sk_buff *skb); 492 int ip_options_rcv_srr(struct sk_buff *skb); 493 494 /* 495 * Functions provided by ip_sockglue.c 496 */ 497 498 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb); 499 void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb); 500 int ip_cmsg_send(struct net *net, struct msghdr *msg, 501 struct ipcm_cookie *ipc, bool allow_ipv6); 502 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, 503 unsigned int optlen); 504 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, 505 int __user *optlen); 506 int compat_ip_setsockopt(struct sock *sk, int level, int optname, 507 char __user *optval, unsigned int optlen); 508 int compat_ip_getsockopt(struct sock *sk, int level, int optname, 509 char __user *optval, int __user *optlen); 510 int ip_ra_control(struct sock *sk, unsigned char on, 511 void (*destructor)(struct sock *)); 512 513 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len); 514 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port, 515 u32 info, u8 *payload); 516 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport, 517 u32 info); 518 519 #ifdef CONFIG_PROC_FS 520 int ip_misc_proc_init(void); 521 #endif 522 523 #endif /* _IP_H */ 524