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, dscp_t dscp, 160 int oif, __u8 scope) 161 { 162 struct flowi4 fl4 = { 163 .flowi4_oif = oif, 164 .flowi4_tos = inet_dscp_to_dsfield(dscp), 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 } 201 202 enum skb_drop_reason 203 ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 204 dscp_t dscp, struct net_device *dev, 205 struct in_device *in_dev, u32 *itag); 206 enum skb_drop_reason 207 ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 208 dscp_t dscp, struct net_device *dev); 209 enum skb_drop_reason 210 ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 211 dscp_t dscp, struct net_device *dev, 212 const struct sk_buff *hint); 213 214 static inline enum skb_drop_reason 215 ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, dscp_t dscp, 216 struct net_device *devin) 217 { 218 enum skb_drop_reason reason; 219 220 rcu_read_lock(); 221 reason = ip_route_input_noref(skb, dst, src, dscp, devin); 222 if (!reason) { 223 skb_dst_force(skb); 224 if (!skb_dst(skb)) 225 reason = SKB_DROP_REASON_NOT_SPECIFIED; 226 } 227 rcu_read_unlock(); 228 229 return reason; 230 } 231 232 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 233 u8 protocol); 234 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 235 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 236 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 237 void ip_rt_send_redirect(struct sk_buff *skb); 238 239 unsigned int inet_addr_type(struct net *net, __be32 addr); 240 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 241 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 242 __be32 addr); 243 unsigned int inet_addr_type_dev_table(struct net *net, 244 const struct net_device *dev, 245 __be32 addr); 246 void ip_rt_multicast_event(struct in_device *); 247 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 248 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 249 struct rtable *rt_dst_alloc(struct net_device *dev, 250 unsigned int flags, u16 type, bool noxfrm); 251 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt); 252 253 struct in_ifaddr; 254 void fib_add_ifaddr(struct in_ifaddr *); 255 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 256 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 257 258 void rt_add_uncached_list(struct rtable *rt); 259 void rt_del_uncached_list(struct rtable *rt); 260 261 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 262 u32 table_id, struct fib_info *fi, 263 int *fa_index, int fa_start, unsigned int flags); 264 265 static inline void ip_rt_put(struct rtable *rt) 266 { 267 /* dst_release() accepts a NULL parameter. 268 * We rely on dst being first structure in struct rtable 269 */ 270 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 271 dst_release(&rt->dst); 272 } 273 274 extern const __u8 ip_tos2prio[16]; 275 276 static inline char rt_tos2priority(u8 tos) 277 { 278 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 279 } 280 281 /* ip_route_connect() and ip_route_newports() work in tandem whilst 282 * binding a socket for a new outgoing connection. 283 * 284 * In order to use IPSEC properly, we must, in the end, have a 285 * route that was looked up using all available keys including source 286 * and destination ports. 287 * 288 * However, if a source port needs to be allocated (the user specified 289 * a wildcard source port) we need to obtain addressing information 290 * in order to perform that allocation. 291 * 292 * So ip_route_connect() looks up a route using wildcarded source and 293 * destination ports in the key, simply so that we can get a pair of 294 * addresses to use for port allocation. 295 * 296 * Later, once the ports are allocated, ip_route_newports() will make 297 * another route lookup if needed to make sure we catch any IPSEC 298 * rules keyed on the port information. 299 * 300 * The callers allocate the flow key on their stack, and must pass in 301 * the same flowi4 object to both the ip_route_connect() and the 302 * ip_route_newports() calls. 303 */ 304 305 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, 306 __be32 src, int oif, u8 protocol, 307 __be16 sport, __be16 dport, 308 const struct sock *sk) 309 { 310 __u8 flow_flags = 0; 311 312 if (inet_test_bit(TRANSPARENT, sk)) 313 flow_flags |= FLOWI_FLAG_ANYSRC; 314 315 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk), 316 ip_sock_rt_scope(sk), protocol, flow_flags, dst, 317 src, dport, sport, sk->sk_uid); 318 } 319 320 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst, 321 __be32 src, int oif, u8 protocol, 322 __be16 sport, __be16 dport, 323 const struct sock *sk) 324 { 325 struct net *net = sock_net(sk); 326 struct rtable *rt; 327 328 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk); 329 330 if (!dst || !src) { 331 rt = __ip_route_output_key(net, fl4); 332 if (IS_ERR(rt)) 333 return rt; 334 ip_rt_put(rt); 335 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr); 336 } 337 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 338 return ip_route_output_flow(net, fl4, sk); 339 } 340 341 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 342 __be16 orig_sport, __be16 orig_dport, 343 __be16 sport, __be16 dport, 344 const struct sock *sk) 345 { 346 if (sport != orig_sport || dport != orig_dport) { 347 fl4->fl4_dport = dport; 348 fl4->fl4_sport = sport; 349 ip_rt_put(rt); 350 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr, 351 fl4->saddr); 352 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 353 return ip_route_output_flow(sock_net(sk), fl4, sk); 354 } 355 return rt; 356 } 357 358 static inline int inet_iif(const struct sk_buff *skb) 359 { 360 struct rtable *rt = skb_rtable(skb); 361 362 if (rt && rt->rt_iif) 363 return rt->rt_iif; 364 365 return skb->skb_iif; 366 } 367 368 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 369 { 370 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 371 struct net *net = dev_net(dst->dev); 372 373 if (hoplimit == 0) 374 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); 375 return hoplimit; 376 } 377 378 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 379 __be32 daddr) 380 { 381 struct neighbour *neigh; 382 383 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr); 384 if (unlikely(!neigh)) 385 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 386 387 return neigh; 388 } 389 390 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 391 struct sk_buff *skb, 392 bool *is_v6gw) 393 { 394 struct net_device *dev = rt->dst.dev; 395 struct neighbour *neigh; 396 397 if (likely(rt->rt_gw_family == AF_INET)) { 398 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 399 } else if (rt->rt_gw_family == AF_INET6) { 400 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 401 *is_v6gw = true; 402 } else { 403 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 404 } 405 return neigh; 406 } 407 408 #endif /* _ROUTE_H */ 409