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 <linux/in_route.h> 31 #include <linux/rtnetlink.h> 32 #include <linux/rcupdate.h> 33 #include <linux/route.h> 34 #include <linux/ip.h> 35 #include <linux/cache.h> 36 #include <linux/security.h> 37 38 static inline __u8 ip_sock_rt_scope(const struct sock *sk) 39 { 40 if (sock_flag(sk, SOCK_LOCALROUTE)) 41 return RT_SCOPE_LINK; 42 43 return RT_SCOPE_UNIVERSE; 44 } 45 46 static inline __u8 ip_sock_rt_tos(const struct sock *sk) 47 { 48 return RT_TOS(READ_ONCE(inet_sk(sk)->tos)); 49 } 50 51 struct ip_tunnel_info; 52 struct fib_nh; 53 struct fib_info; 54 struct uncached_list; 55 struct rtable { 56 struct dst_entry dst; 57 58 int rt_genid; 59 unsigned int rt_flags; 60 __u16 rt_type; 61 __u8 rt_is_input; 62 __u8 rt_uses_gateway; 63 64 int rt_iif; 65 66 u8 rt_gw_family; 67 /* Info on neighbour */ 68 union { 69 __be32 rt_gw4; 70 struct in6_addr rt_gw6; 71 }; 72 73 /* Miscellaneous cached information */ 74 u32 rt_mtu_locked:1, 75 rt_pmtu:31; 76 }; 77 78 #define dst_rtable(_ptr) container_of_const(_ptr, struct rtable, dst) 79 80 /** 81 * skb_rtable - Returns the skb &rtable 82 * @skb: buffer 83 */ 84 static inline struct rtable *skb_rtable(const struct sk_buff *skb) 85 { 86 return dst_rtable(skb_dst(skb)); 87 } 88 89 static inline bool rt_is_input_route(const struct rtable *rt) 90 { 91 return rt->rt_is_input != 0; 92 } 93 94 static inline bool rt_is_output_route(const struct rtable *rt) 95 { 96 return rt->rt_is_input == 0; 97 } 98 99 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 100 { 101 if (rt->rt_gw_family == AF_INET) 102 return rt->rt_gw4; 103 return daddr; 104 } 105 106 struct ip_rt_acct { 107 __u32 o_bytes; 108 __u32 o_packets; 109 __u32 i_bytes; 110 __u32 i_packets; 111 }; 112 113 struct rt_cache_stat { 114 unsigned int in_slow_tot; 115 unsigned int in_slow_mc; 116 unsigned int in_no_route; 117 unsigned int in_brd; 118 unsigned int in_martian_dst; 119 unsigned int in_martian_src; 120 unsigned int out_slow_tot; 121 unsigned int out_slow_mc; 122 }; 123 124 extern struct ip_rt_acct __percpu *ip_rt_acct; 125 126 struct in_device; 127 128 int ip_rt_init(void); 129 void rt_cache_flush(struct net *net); 130 void rt_flush_dev(struct net_device *dev); 131 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 132 const struct sk_buff *skb); 133 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 134 struct fib_result *res, 135 const struct sk_buff *skb); 136 137 static inline struct rtable *__ip_route_output_key(struct net *net, 138 struct flowi4 *flp) 139 { 140 return ip_route_output_key_hash(net, flp, NULL); 141 } 142 143 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 144 const struct sock *sk); 145 struct dst_entry *ipv4_blackhole_route(struct net *net, 146 struct dst_entry *dst_orig); 147 148 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 149 { 150 return ip_route_output_flow(net, flp, NULL); 151 } 152 153 /* Simplistic IPv4 route lookup function. 154 * This is only suitable for some particular use cases: since the flowi4 155 * structure is only partially set, it may bypass some fib-rules. 156 */ 157 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 158 __be32 saddr, u8 tos, int oif, 159 __u8 scope) 160 { 161 struct flowi4 fl4 = { 162 .flowi4_oif = oif, 163 .flowi4_tos = tos, 164 .flowi4_scope = scope, 165 .daddr = daddr, 166 .saddr = saddr, 167 }; 168 169 return ip_route_output_key(net, &fl4); 170 } 171 172 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 173 const struct sock *sk, 174 __be32 daddr, __be32 saddr, 175 __be16 dport, __be16 sport, 176 __u8 proto, __u8 tos, int oif) 177 { 178 flowi4_init_output(fl4, oif, sk ? READ_ONCE(sk->sk_mark) : 0, tos, 179 sk ? ip_sock_rt_scope(sk) : RT_SCOPE_UNIVERSE, 180 proto, sk ? inet_sk_flowi_flags(sk) : 0, 181 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 182 if (sk) 183 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 184 return ip_route_output_flow(net, fl4, sk); 185 } 186 187 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 188 __be32 daddr, __be32 saddr, 189 __be32 gre_key, __u8 tos, int oif) 190 { 191 memset(fl4, 0, sizeof(*fl4)); 192 fl4->flowi4_oif = oif; 193 fl4->daddr = daddr; 194 fl4->saddr = saddr; 195 fl4->flowi4_tos = tos; 196 fl4->flowi4_proto = IPPROTO_GRE; 197 fl4->fl4_gre_key = gre_key; 198 return ip_route_output_key(net, fl4); 199 } 200 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 201 u8 tos, struct net_device *dev, 202 struct in_device *in_dev, u32 *itag); 203 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 204 u8 tos, struct net_device *devin); 205 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src, 206 u8 tos, struct net_device *devin, 207 const struct sk_buff *hint); 208 209 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 210 u8 tos, struct net_device *devin) 211 { 212 int err; 213 214 rcu_read_lock(); 215 err = ip_route_input_noref(skb, dst, src, tos, devin); 216 if (!err) { 217 skb_dst_force(skb); 218 if (!skb_dst(skb)) 219 err = -EINVAL; 220 } 221 rcu_read_unlock(); 222 223 return err; 224 } 225 226 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 227 u8 protocol); 228 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 229 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 230 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 231 void ip_rt_send_redirect(struct sk_buff *skb); 232 233 unsigned int inet_addr_type(struct net *net, __be32 addr); 234 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 235 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 236 __be32 addr); 237 unsigned int inet_addr_type_dev_table(struct net *net, 238 const struct net_device *dev, 239 __be32 addr); 240 void ip_rt_multicast_event(struct in_device *); 241 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 242 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 243 struct rtable *rt_dst_alloc(struct net_device *dev, 244 unsigned int flags, u16 type, bool noxfrm); 245 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt); 246 247 struct in_ifaddr; 248 void fib_add_ifaddr(struct in_ifaddr *); 249 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 250 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 251 252 void rt_add_uncached_list(struct rtable *rt); 253 void rt_del_uncached_list(struct rtable *rt); 254 255 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 256 u32 table_id, struct fib_info *fi, 257 int *fa_index, int fa_start, unsigned int flags); 258 259 static inline void ip_rt_put(struct rtable *rt) 260 { 261 /* dst_release() accepts a NULL parameter. 262 * We rely on dst being first structure in struct rtable 263 */ 264 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 265 dst_release(&rt->dst); 266 } 267 268 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 269 270 extern const __u8 ip_tos2prio[16]; 271 272 static inline char rt_tos2priority(u8 tos) 273 { 274 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 275 } 276 277 /* ip_route_connect() and ip_route_newports() work in tandem whilst 278 * binding a socket for a new outgoing connection. 279 * 280 * In order to use IPSEC properly, we must, in the end, have a 281 * route that was looked up using all available keys including source 282 * and destination ports. 283 * 284 * However, if a source port needs to be allocated (the user specified 285 * a wildcard source port) we need to obtain addressing information 286 * in order to perform that allocation. 287 * 288 * So ip_route_connect() looks up a route using wildcarded source and 289 * destination ports in the key, simply so that we can get a pair of 290 * addresses to use for port allocation. 291 * 292 * Later, once the ports are allocated, ip_route_newports() will make 293 * another route lookup if needed to make sure we catch any IPSEC 294 * rules keyed on the port information. 295 * 296 * The callers allocate the flow key on their stack, and must pass in 297 * the same flowi4 object to both the ip_route_connect() and the 298 * ip_route_newports() calls. 299 */ 300 301 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, 302 __be32 src, int oif, u8 protocol, 303 __be16 sport, __be16 dport, 304 const struct sock *sk) 305 { 306 __u8 flow_flags = 0; 307 308 if (inet_test_bit(TRANSPARENT, sk)) 309 flow_flags |= FLOWI_FLAG_ANYSRC; 310 311 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk), 312 ip_sock_rt_scope(sk), protocol, flow_flags, dst, 313 src, dport, sport, sk->sk_uid); 314 } 315 316 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst, 317 __be32 src, int oif, u8 protocol, 318 __be16 sport, __be16 dport, 319 const struct sock *sk) 320 { 321 struct net *net = sock_net(sk); 322 struct rtable *rt; 323 324 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk); 325 326 if (!dst || !src) { 327 rt = __ip_route_output_key(net, fl4); 328 if (IS_ERR(rt)) 329 return rt; 330 ip_rt_put(rt); 331 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr); 332 } 333 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 334 return ip_route_output_flow(net, fl4, sk); 335 } 336 337 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 338 __be16 orig_sport, __be16 orig_dport, 339 __be16 sport, __be16 dport, 340 const struct sock *sk) 341 { 342 if (sport != orig_sport || dport != orig_dport) { 343 fl4->fl4_dport = dport; 344 fl4->fl4_sport = sport; 345 ip_rt_put(rt); 346 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr, 347 fl4->saddr); 348 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 349 return ip_route_output_flow(sock_net(sk), fl4, sk); 350 } 351 return rt; 352 } 353 354 static inline int inet_iif(const struct sk_buff *skb) 355 { 356 struct rtable *rt = skb_rtable(skb); 357 358 if (rt && rt->rt_iif) 359 return rt->rt_iif; 360 361 return skb->skb_iif; 362 } 363 364 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 365 { 366 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 367 struct net *net = dev_net(dst->dev); 368 369 if (hoplimit == 0) 370 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); 371 return hoplimit; 372 } 373 374 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 375 __be32 daddr) 376 { 377 struct neighbour *neigh; 378 379 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr); 380 if (unlikely(!neigh)) 381 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 382 383 return neigh; 384 } 385 386 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 387 struct sk_buff *skb, 388 bool *is_v6gw) 389 { 390 struct net_device *dev = rt->dst.dev; 391 struct neighbour *neigh; 392 393 if (likely(rt->rt_gw_family == AF_INET)) { 394 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 395 } else if (rt->rt_gw_family == AF_INET6) { 396 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 397 *is_v6gw = true; 398 } else { 399 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 400 } 401 return neigh; 402 } 403 404 #endif /* _ROUTE_H */ 405