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