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 #define RTO_ONLINK 0x01 39 40 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE)) 41 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE)) 42 43 static inline __u8 ip_sock_rt_scope(const struct sock *sk) 44 { 45 if (sock_flag(sk, SOCK_LOCALROUTE)) 46 return RT_SCOPE_LINK; 47 48 return RT_SCOPE_UNIVERSE; 49 } 50 51 static inline __u8 ip_sock_rt_tos(const struct sock *sk) 52 { 53 return RT_TOS(inet_sk(sk)->tos); 54 } 55 56 struct ip_tunnel_info; 57 struct fib_nh; 58 struct fib_info; 59 struct uncached_list; 60 struct rtable { 61 struct dst_entry dst; 62 63 int rt_genid; 64 unsigned int rt_flags; 65 __u16 rt_type; 66 __u8 rt_is_input; 67 __u8 rt_uses_gateway; 68 69 int rt_iif; 70 71 u8 rt_gw_family; 72 /* Info on neighbour */ 73 union { 74 __be32 rt_gw4; 75 struct in6_addr rt_gw6; 76 }; 77 78 /* Miscellaneous cached information */ 79 u32 rt_mtu_locked:1, 80 rt_pmtu:31; 81 82 struct list_head rt_uncached; 83 struct uncached_list *rt_uncached_list; 84 }; 85 86 static inline bool rt_is_input_route(const struct rtable *rt) 87 { 88 return rt->rt_is_input != 0; 89 } 90 91 static inline bool rt_is_output_route(const struct rtable *rt) 92 { 93 return rt->rt_is_input == 0; 94 } 95 96 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 97 { 98 if (rt->rt_gw_family == AF_INET) 99 return rt->rt_gw4; 100 return daddr; 101 } 102 103 struct ip_rt_acct { 104 __u32 o_bytes; 105 __u32 o_packets; 106 __u32 i_bytes; 107 __u32 i_packets; 108 }; 109 110 struct rt_cache_stat { 111 unsigned int in_slow_tot; 112 unsigned int in_slow_mc; 113 unsigned int in_no_route; 114 unsigned int in_brd; 115 unsigned int in_martian_dst; 116 unsigned int in_martian_src; 117 unsigned int out_slow_tot; 118 unsigned int out_slow_mc; 119 }; 120 121 extern struct ip_rt_acct __percpu *ip_rt_acct; 122 123 struct in_device; 124 125 int ip_rt_init(void); 126 void rt_cache_flush(struct net *net); 127 void rt_flush_dev(struct net_device *dev); 128 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 129 const struct sk_buff *skb); 130 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 131 struct fib_result *res, 132 const struct sk_buff *skb); 133 134 static inline struct rtable *__ip_route_output_key(struct net *net, 135 struct flowi4 *flp) 136 { 137 return ip_route_output_key_hash(net, flp, NULL); 138 } 139 140 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 141 const struct sock *sk); 142 struct rtable *ip_route_output_tunnel(struct sk_buff *skb, 143 struct net_device *dev, 144 struct net *net, __be32 *saddr, 145 const struct ip_tunnel_info *info, 146 u8 protocol, bool use_cache); 147 148 struct dst_entry *ipv4_blackhole_route(struct net *net, 149 struct dst_entry *dst_orig); 150 151 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 152 { 153 return ip_route_output_flow(net, flp, NULL); 154 } 155 156 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 157 __be32 saddr, u8 tos, int oif) 158 { 159 struct flowi4 fl4 = { 160 .flowi4_oif = oif, 161 .flowi4_tos = tos, 162 .daddr = daddr, 163 .saddr = saddr, 164 }; 165 return ip_route_output_key(net, &fl4); 166 } 167 168 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 169 struct sock *sk, 170 __be32 daddr, __be32 saddr, 171 __be16 dport, __be16 sport, 172 __u8 proto, __u8 tos, int oif) 173 { 174 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 175 RT_SCOPE_UNIVERSE, proto, 176 sk ? inet_sk_flowi_flags(sk) : 0, 177 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 178 if (sk) 179 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 180 return ip_route_output_flow(net, fl4, sk); 181 } 182 183 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 184 __be32 daddr, __be32 saddr, 185 __be32 gre_key, __u8 tos, int oif) 186 { 187 memset(fl4, 0, sizeof(*fl4)); 188 fl4->flowi4_oif = oif; 189 fl4->daddr = daddr; 190 fl4->saddr = saddr; 191 fl4->flowi4_tos = tos; 192 fl4->flowi4_proto = IPPROTO_GRE; 193 fl4->fl4_gre_key = gre_key; 194 return ip_route_output_key(net, fl4); 195 } 196 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 197 u8 tos, struct net_device *dev, 198 struct in_device *in_dev, u32 *itag); 199 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 200 u8 tos, struct net_device *devin); 201 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src, 202 u8 tos, struct net_device *devin, 203 const struct sk_buff *hint); 204 205 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 206 u8 tos, struct net_device *devin) 207 { 208 int err; 209 210 rcu_read_lock(); 211 err = ip_route_input_noref(skb, dst, src, tos, devin); 212 if (!err) { 213 skb_dst_force(skb); 214 if (!skb_dst(skb)) 215 err = -EINVAL; 216 } 217 rcu_read_unlock(); 218 219 return err; 220 } 221 222 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 223 u8 protocol); 224 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 225 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 226 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 227 void ip_rt_send_redirect(struct sk_buff *skb); 228 229 unsigned int inet_addr_type(struct net *net, __be32 addr); 230 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 231 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 232 __be32 addr); 233 unsigned int inet_addr_type_dev_table(struct net *net, 234 const struct net_device *dev, 235 __be32 addr); 236 void ip_rt_multicast_event(struct in_device *); 237 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 238 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 239 struct rtable *rt_dst_alloc(struct net_device *dev, 240 unsigned int flags, u16 type, bool noxfrm); 241 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt); 242 243 struct in_ifaddr; 244 void fib_add_ifaddr(struct in_ifaddr *); 245 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 246 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 247 248 void rt_add_uncached_list(struct rtable *rt); 249 void rt_del_uncached_list(struct rtable *rt); 250 251 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 252 u32 table_id, struct fib_info *fi, 253 int *fa_index, int fa_start, unsigned int flags); 254 255 static inline void ip_rt_put(struct rtable *rt) 256 { 257 /* dst_release() accepts a NULL parameter. 258 * We rely on dst being first structure in struct rtable 259 */ 260 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 261 dst_release(&rt->dst); 262 } 263 264 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 265 266 extern const __u8 ip_tos2prio[16]; 267 268 static inline char rt_tos2priority(u8 tos) 269 { 270 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 271 } 272 273 /* ip_route_connect() and ip_route_newports() work in tandem whilst 274 * binding a socket for a new outgoing connection. 275 * 276 * In order to use IPSEC properly, we must, in the end, have a 277 * route that was looked up using all available keys including source 278 * and destination ports. 279 * 280 * However, if a source port needs to be allocated (the user specified 281 * a wildcard source port) we need to obtain addressing information 282 * in order to perform that allocation. 283 * 284 * So ip_route_connect() looks up a route using wildcarded source and 285 * destination ports in the key, simply so that we can get a pair of 286 * addresses to use for port allocation. 287 * 288 * Later, once the ports are allocated, ip_route_newports() will make 289 * another route lookup if needed to make sure we catch any IPSEC 290 * rules keyed on the port information. 291 * 292 * The callers allocate the flow key on their stack, and must pass in 293 * the same flowi4 object to both the ip_route_connect() and the 294 * ip_route_newports() calls. 295 */ 296 297 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, 298 __be32 src, int oif, u8 protocol, 299 __be16 sport, __be16 dport, 300 const struct sock *sk) 301 { 302 __u8 flow_flags = 0; 303 304 if (inet_sk(sk)->transparent) 305 flow_flags |= FLOWI_FLAG_ANYSRC; 306 307 flowi4_init_output(fl4, oif, sk->sk_mark, ip_sock_rt_tos(sk), 308 ip_sock_rt_scope(sk), protocol, flow_flags, dst, 309 src, dport, sport, sk->sk_uid); 310 } 311 312 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst, 313 __be32 src, int oif, u8 protocol, 314 __be16 sport, __be16 dport, 315 struct sock *sk) 316 { 317 struct net *net = sock_net(sk); 318 struct rtable *rt; 319 320 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk); 321 322 if (!dst || !src) { 323 rt = __ip_route_output_key(net, fl4); 324 if (IS_ERR(rt)) 325 return rt; 326 ip_rt_put(rt); 327 flowi4_update_output(fl4, oif, fl4->flowi4_tos, fl4->daddr, 328 fl4->saddr); 329 } 330 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 331 return ip_route_output_flow(net, fl4, sk); 332 } 333 334 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 335 __be16 orig_sport, __be16 orig_dport, 336 __be16 sport, __be16 dport, 337 struct sock *sk) 338 { 339 if (sport != orig_sport || dport != orig_dport) { 340 fl4->fl4_dport = dport; 341 fl4->fl4_sport = sport; 342 ip_rt_put(rt); 343 flowi4_update_output(fl4, sk->sk_bound_dev_if, 344 RT_CONN_FLAGS(sk), fl4->daddr, 345 fl4->saddr); 346 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 347 return ip_route_output_flow(sock_net(sk), fl4, sk); 348 } 349 return rt; 350 } 351 352 static inline int inet_iif(const struct sk_buff *skb) 353 { 354 struct rtable *rt = skb_rtable(skb); 355 356 if (rt && rt->rt_iif) 357 return rt->rt_iif; 358 359 return skb->skb_iif; 360 } 361 362 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 363 { 364 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 365 struct net *net = dev_net(dst->dev); 366 367 if (hoplimit == 0) 368 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); 369 return hoplimit; 370 } 371 372 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 373 __be32 daddr) 374 { 375 struct neighbour *neigh; 376 377 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr); 378 if (unlikely(!neigh)) 379 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 380 381 return neigh; 382 } 383 384 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 385 struct sk_buff *skb, 386 bool *is_v6gw) 387 { 388 struct net_device *dev = rt->dst.dev; 389 struct neighbour *neigh; 390 391 if (likely(rt->rt_gw_family == AF_INET)) { 392 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 393 } else if (rt->rt_gw_family == AF_INET6) { 394 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 395 *is_v6gw = true; 396 } else { 397 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 398 } 399 return neigh; 400 } 401 402 #endif /* _ROUTE_H */ 403