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