1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Definitions for the IP router. 8 * 9 * Version: @(#)route.h 1.0.4 05/27/93 10 * 11 * Authors: Ross Biro 12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 13 * Fixes: 14 * Alan Cox : Reformatted. Added ip_rt_local() 15 * Alan Cox : Support for TCP parameters. 16 * Alexey Kuznetsov: Major changes for new routing code. 17 * Mike McLagan : Routing by source 18 * Robert Olsson : Added rt_cache statistics 19 */ 20 #ifndef _ROUTE_H 21 #define _ROUTE_H 22 23 #include <net/dst.h> 24 #include <net/inetpeer.h> 25 #include <net/flow.h> 26 #include <net/inet_sock.h> 27 #include <net/ip_fib.h> 28 #include <net/arp.h> 29 #include <net/ndisc.h> 30 #include <net/inet_dscp.h> 31 #include <net/sock.h> 32 #include <linux/in_route.h> 33 #include <linux/rtnetlink.h> 34 #include <linux/rcupdate.h> 35 #include <linux/route.h> 36 #include <linux/ip.h> 37 #include <linux/cache.h> 38 #include <linux/security.h> 39 40 static inline __u8 ip_sock_rt_scope(const struct sock *sk) 41 { 42 if (sock_flag(sk, SOCK_LOCALROUTE)) 43 return RT_SCOPE_LINK; 44 45 return RT_SCOPE_UNIVERSE; 46 } 47 48 static inline __u8 ip_sock_rt_tos(const struct sock *sk) 49 { 50 return READ_ONCE(inet_sk(sk)->tos) & INET_DSCP_MASK; 51 } 52 53 struct ip_tunnel_info; 54 struct fib_nh; 55 struct fib_info; 56 struct uncached_list; 57 struct rtable { 58 struct dst_entry dst; 59 60 int rt_genid; 61 unsigned int rt_flags; 62 __u16 rt_type; 63 __u8 rt_is_input; 64 __u8 rt_uses_gateway; 65 66 int rt_iif; 67 68 u8 rt_gw_family; 69 /* Info on neighbour */ 70 union { 71 __be32 rt_gw4; 72 struct in6_addr rt_gw6; 73 }; 74 75 /* Miscellaneous cached information */ 76 u32 rt_mtu_locked:1, 77 rt_pmtu:31; 78 }; 79 80 #define dst_rtable(_ptr) container_of_const(_ptr, struct rtable, dst) 81 82 /** 83 * skb_rtable - Returns the skb &rtable 84 * @skb: buffer 85 */ 86 static inline struct rtable *skb_rtable(const struct sk_buff *skb) 87 { 88 return dst_rtable(skb_dst(skb)); 89 } 90 91 static inline bool rt_is_input_route(const struct rtable *rt) 92 { 93 return rt->rt_is_input != 0; 94 } 95 96 static inline bool rt_is_output_route(const struct rtable *rt) 97 { 98 return rt->rt_is_input == 0; 99 } 100 101 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 102 { 103 if (rt->rt_gw_family == AF_INET) 104 return rt->rt_gw4; 105 return daddr; 106 } 107 108 struct ip_rt_acct { 109 __u32 o_bytes; 110 __u32 o_packets; 111 __u32 i_bytes; 112 __u32 i_packets; 113 }; 114 115 struct rt_cache_stat { 116 unsigned int in_slow_tot; 117 unsigned int in_slow_mc; 118 unsigned int in_no_route; 119 unsigned int in_brd; 120 unsigned int in_martian_dst; 121 unsigned int in_martian_src; 122 unsigned int out_slow_tot; 123 unsigned int out_slow_mc; 124 }; 125 126 extern struct ip_rt_acct __percpu *ip_rt_acct; 127 128 struct in_device; 129 130 int ip_rt_init(void); 131 void rt_cache_flush(struct net *net); 132 void rt_flush_dev(struct net_device *dev); 133 134 static inline void inet_sk_init_flowi4(const struct inet_sock *inet, 135 struct flowi4 *fl4) 136 { 137 const struct ip_options_rcu *ip4_opt; 138 const struct sock *sk; 139 __be32 daddr; 140 141 rcu_read_lock(); 142 ip4_opt = rcu_dereference(inet->inet_opt); 143 144 /* Source routing option overrides the socket destination address */ 145 if (ip4_opt && ip4_opt->opt.srr) 146 daddr = ip4_opt->opt.faddr; 147 else 148 daddr = inet->inet_daddr; 149 rcu_read_unlock(); 150 151 sk = &inet->sk; 152 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark), 153 ip_sock_rt_tos(sk), ip_sock_rt_scope(sk), 154 sk->sk_protocol, inet_sk_flowi_flags(sk), daddr, 155 inet->inet_saddr, inet->inet_dport, 156 inet->inet_sport, sk_uid(sk)); 157 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 158 } 159 160 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 161 const struct sk_buff *skb); 162 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 163 struct fib_result *res, 164 const struct sk_buff *skb); 165 166 static inline struct rtable *__ip_route_output_key(struct net *net, 167 struct flowi4 *flp) 168 { 169 return ip_route_output_key_hash(net, flp, NULL); 170 } 171 172 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 173 const struct sock *sk); 174 struct dst_entry *ipv4_blackhole_route(struct net *net, 175 struct dst_entry *dst_orig); 176 177 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 178 { 179 return ip_route_output_flow(net, flp, NULL); 180 } 181 182 /* Simplistic IPv4 route lookup function. 183 * This is only suitable for some particular use cases: since the flowi4 184 * structure is only partially set, it may bypass some fib-rules. 185 */ 186 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 187 __be32 saddr, dscp_t dscp, 188 int oif, __u8 scope) 189 { 190 struct flowi4 fl4 = { 191 .flowi4_oif = oif, 192 .flowi4_dscp = dscp, 193 .flowi4_scope = scope, 194 .daddr = daddr, 195 .saddr = saddr, 196 }; 197 198 return ip_route_output_key(net, &fl4); 199 } 200 201 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 202 const struct sock *sk, 203 __be32 daddr, __be32 saddr, 204 __be16 dport, __be16 sport, 205 __u8 proto, __u8 tos, int oif) 206 { 207 flowi4_init_output(fl4, oif, sk ? READ_ONCE(sk->sk_mark) : 0, tos, 208 sk ? ip_sock_rt_scope(sk) : RT_SCOPE_UNIVERSE, 209 proto, sk ? inet_sk_flowi_flags(sk) : 0, 210 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 211 if (sk) 212 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 213 return ip_route_output_flow(net, fl4, sk); 214 } 215 216 enum skb_drop_reason 217 ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 218 dscp_t dscp, struct net_device *dev, 219 struct in_device *in_dev, u32 *itag); 220 enum skb_drop_reason 221 ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 222 dscp_t dscp, struct net_device *dev); 223 enum skb_drop_reason 224 ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 225 dscp_t dscp, struct net_device *dev, 226 const struct sk_buff *hint); 227 228 static inline enum skb_drop_reason 229 ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, dscp_t dscp, 230 struct net_device *devin) 231 { 232 enum skb_drop_reason reason; 233 234 rcu_read_lock(); 235 reason = ip_route_input_noref(skb, dst, src, dscp, devin); 236 if (!reason) { 237 skb_dst_force(skb); 238 if (!skb_dst(skb)) 239 reason = SKB_DROP_REASON_NOT_SPECIFIED; 240 } 241 rcu_read_unlock(); 242 243 return reason; 244 } 245 246 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 247 u8 protocol); 248 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 249 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 250 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 251 void ip_rt_send_redirect(struct sk_buff *skb); 252 253 unsigned int inet_addr_type(struct net *net, __be32 addr); 254 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 255 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 256 __be32 addr); 257 unsigned int inet_addr_type_dev_table(struct net *net, 258 const struct net_device *dev, 259 __be32 addr); 260 void ip_rt_multicast_event(struct in_device *); 261 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 262 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 263 struct rtable *rt_dst_alloc(struct net_device *dev, 264 unsigned int flags, u16 type, bool noxfrm); 265 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt); 266 267 struct in_ifaddr; 268 void fib_add_ifaddr(struct in_ifaddr *); 269 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 270 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 271 272 void rt_add_uncached_list(struct rtable *rt); 273 void rt_del_uncached_list(struct rtable *rt); 274 275 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 276 u32 table_id, struct fib_info *fi, 277 int *fa_index, int fa_start, unsigned int flags); 278 279 void fnhe_update_pmtu(struct fib_nh_exception *fnhe, u32 new, u32 orig); 280 281 static inline void ip_rt_put(struct rtable *rt) 282 { 283 /* dst_release() accepts a NULL parameter. 284 * We rely on dst being first structure in struct rtable 285 */ 286 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 287 dst_release(&rt->dst); 288 } 289 290 extern const __u8 ip_tos2prio[16]; 291 292 static inline char rt_tos2priority(u8 tos) 293 { 294 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 295 } 296 297 /* ip_route_connect() and ip_route_newports() work in tandem whilst 298 * binding a socket for a new outgoing connection. 299 * 300 * In order to use IPSEC properly, we must, in the end, have a 301 * route that was looked up using all available keys including source 302 * and destination ports. 303 * 304 * However, if a source port needs to be allocated (the user specified 305 * a wildcard source port) we need to obtain addressing information 306 * in order to perform that allocation. 307 * 308 * So ip_route_connect() looks up a route using wildcarded source and 309 * destination ports in the key, simply so that we can get a pair of 310 * addresses to use for port allocation. 311 * 312 * Later, once the ports are allocated, ip_route_newports() will make 313 * another route lookup if needed to make sure we catch any IPSEC 314 * rules keyed on the port information. 315 * 316 * The callers allocate the flow key on their stack, and must pass in 317 * the same flowi4 object to both the ip_route_connect() and the 318 * ip_route_newports() calls. 319 */ 320 321 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, 322 __be32 src, int oif, u8 protocol, 323 __be16 sport, __be16 dport, 324 const struct sock *sk) 325 { 326 __u8 flow_flags = 0; 327 328 if (inet_test_bit(TRANSPARENT, sk)) 329 flow_flags |= FLOWI_FLAG_ANYSRC; 330 331 if (IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) && !sport) 332 flow_flags |= FLOWI_FLAG_ANY_SPORT; 333 334 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk), 335 ip_sock_rt_scope(sk), protocol, flow_flags, dst, 336 src, dport, sport, sk_uid(sk)); 337 } 338 339 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst, 340 __be32 src, int oif, u8 protocol, 341 __be16 sport, __be16 dport, 342 const struct sock *sk) 343 { 344 struct net *net = sock_net(sk); 345 struct rtable *rt; 346 347 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk); 348 349 if (!dst || !src) { 350 rt = __ip_route_output_key(net, fl4); 351 if (IS_ERR(rt)) 352 return rt; 353 ip_rt_put(rt); 354 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr); 355 } 356 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 357 return ip_route_output_flow(net, fl4, sk); 358 } 359 360 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 361 __be16 orig_sport, __be16 orig_dport, 362 __be16 sport, __be16 dport, 363 const struct sock *sk) 364 { 365 if (sport != orig_sport || dport != orig_dport) { 366 fl4->fl4_dport = dport; 367 fl4->fl4_sport = sport; 368 ip_rt_put(rt); 369 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr, 370 fl4->saddr); 371 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 372 return ip_route_output_flow(sock_net(sk), fl4, sk); 373 } 374 return rt; 375 } 376 377 static inline int inet_iif(const struct sk_buff *skb) 378 { 379 struct rtable *rt = skb_rtable(skb); 380 381 if (rt && rt->rt_iif) 382 return rt->rt_iif; 383 384 return skb->skb_iif; 385 } 386 387 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 388 { 389 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 390 391 if (hoplimit == 0) { 392 const struct net *net; 393 394 rcu_read_lock(); 395 net = dst_dev_net_rcu(dst); 396 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); 397 rcu_read_unlock(); 398 } 399 return hoplimit; 400 } 401 402 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 403 __be32 daddr) 404 { 405 struct neighbour *neigh; 406 407 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr); 408 if (unlikely(!neigh)) 409 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 410 411 return neigh; 412 } 413 414 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 415 struct sk_buff *skb, 416 bool *is_v6gw) 417 { 418 struct net_device *dev = rt->dst.dev; 419 struct neighbour *neigh; 420 421 if (likely(rt->rt_gw_family == AF_INET)) { 422 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 423 } else if (rt->rt_gw_family == AF_INET6) { 424 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 425 *is_v6gw = true; 426 } else { 427 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 428 } 429 return neigh; 430 } 431 432 #endif /* _ROUTE_H */ 433