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 /* IPv4 datagram length is stored into 16bit field (tot_len) */ 39 #define IP_MAX_MTU 0xFFFFU 40 41 #define RTO_ONLINK 0x01 42 43 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE)) 44 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE)) 45 46 static inline __u8 ip_sock_rt_scope(const struct sock *sk) 47 { 48 if (sock_flag(sk, SOCK_LOCALROUTE)) 49 return RT_SCOPE_LINK; 50 51 return RT_SCOPE_UNIVERSE; 52 } 53 54 static inline __u8 ip_sock_rt_tos(const struct sock *sk) 55 { 56 return RT_TOS(inet_sk(sk)->tos); 57 } 58 59 struct ip_tunnel_info; 60 struct fib_nh; 61 struct fib_info; 62 struct uncached_list; 63 struct rtable { 64 struct dst_entry dst; 65 66 int rt_genid; 67 unsigned int rt_flags; 68 __u16 rt_type; 69 __u8 rt_is_input; 70 __u8 rt_uses_gateway; 71 72 int rt_iif; 73 74 u8 rt_gw_family; 75 /* Info on neighbour */ 76 union { 77 __be32 rt_gw4; 78 struct in6_addr rt_gw6; 79 }; 80 81 /* Miscellaneous cached information */ 82 u32 rt_mtu_locked:1, 83 rt_pmtu:31; 84 85 struct list_head rt_uncached; 86 struct uncached_list *rt_uncached_list; 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 rtable *ip_route_output_tunnel(struct sk_buff *skb, 146 struct net_device *dev, 147 struct net *net, __be32 *saddr, 148 const struct ip_tunnel_info *info, 149 u8 protocol, bool use_cache); 150 151 struct dst_entry *ipv4_blackhole_route(struct net *net, 152 struct dst_entry *dst_orig); 153 154 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 155 { 156 return ip_route_output_flow(net, flp, NULL); 157 } 158 159 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 160 __be32 saddr, u8 tos, int oif) 161 { 162 struct flowi4 fl4 = { 163 .flowi4_oif = oif, 164 .flowi4_tos = tos, 165 .daddr = daddr, 166 .saddr = saddr, 167 }; 168 return ip_route_output_key(net, &fl4); 169 } 170 171 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 172 struct sock *sk, 173 __be32 daddr, __be32 saddr, 174 __be16 dport, __be16 sport, 175 __u8 proto, __u8 tos, int oif) 176 { 177 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 178 RT_SCOPE_UNIVERSE, proto, 179 sk ? inet_sk_flowi_flags(sk) : 0, 180 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 181 if (sk) 182 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 183 return ip_route_output_flow(net, fl4, sk); 184 } 185 186 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 187 __be32 daddr, __be32 saddr, 188 __be32 gre_key, __u8 tos, int oif) 189 { 190 memset(fl4, 0, sizeof(*fl4)); 191 fl4->flowi4_oif = oif; 192 fl4->daddr = daddr; 193 fl4->saddr = saddr; 194 fl4->flowi4_tos = tos; 195 fl4->flowi4_proto = IPPROTO_GRE; 196 fl4->fl4_gre_key = gre_key; 197 return ip_route_output_key(net, fl4); 198 } 199 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 200 u8 tos, struct net_device *dev, 201 struct in_device *in_dev, u32 *itag); 202 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 203 u8 tos, struct net_device *devin); 204 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src, 205 u8 tos, struct net_device *devin, 206 const struct sk_buff *hint); 207 208 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 209 u8 tos, struct net_device *devin) 210 { 211 int err; 212 213 rcu_read_lock(); 214 err = ip_route_input_noref(skb, dst, src, tos, devin); 215 if (!err) { 216 skb_dst_force(skb); 217 if (!skb_dst(skb)) 218 err = -EINVAL; 219 } 220 rcu_read_unlock(); 221 222 return err; 223 } 224 225 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 226 u8 protocol); 227 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 228 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 229 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 230 void ip_rt_send_redirect(struct sk_buff *skb); 231 232 unsigned int inet_addr_type(struct net *net, __be32 addr); 233 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 234 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 235 __be32 addr); 236 unsigned int inet_addr_type_dev_table(struct net *net, 237 const struct net_device *dev, 238 __be32 addr); 239 void ip_rt_multicast_event(struct in_device *); 240 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 241 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 242 struct rtable *rt_dst_alloc(struct net_device *dev, 243 unsigned int flags, u16 type, bool noxfrm); 244 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt); 245 246 struct in_ifaddr; 247 void fib_add_ifaddr(struct in_ifaddr *); 248 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 249 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 250 251 void rt_add_uncached_list(struct rtable *rt); 252 void rt_del_uncached_list(struct rtable *rt); 253 254 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb, 255 u32 table_id, struct fib_info *fi, 256 int *fa_index, int fa_start, unsigned int flags); 257 258 static inline void ip_rt_put(struct rtable *rt) 259 { 260 /* dst_release() accepts a NULL parameter. 261 * We rely on dst being first structure in struct rtable 262 */ 263 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 264 dst_release(&rt->dst); 265 } 266 267 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 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_sk(sk)->transparent) 308 flow_flags |= FLOWI_FLAG_ANYSRC; 309 310 flowi4_init_output(fl4, oif, 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 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->flowi4_tos, fl4->daddr, 331 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 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, 347 RT_CONN_FLAGS(sk), fl4->daddr, 348 fl4->saddr); 349 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 350 return ip_route_output_flow(sock_net(sk), fl4, sk); 351 } 352 return rt; 353 } 354 355 static inline int inet_iif(const struct sk_buff *skb) 356 { 357 struct rtable *rt = skb_rtable(skb); 358 359 if (rt && rt->rt_iif) 360 return rt->rt_iif; 361 362 return skb->skb_iif; 363 } 364 365 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 366 { 367 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 368 struct net *net = dev_net(dst->dev); 369 370 if (hoplimit == 0) 371 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); 372 return hoplimit; 373 } 374 375 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 376 __be32 daddr) 377 { 378 struct neighbour *neigh; 379 380 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr); 381 if (unlikely(!neigh)) 382 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 383 384 return neigh; 385 } 386 387 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 388 struct sk_buff *skb, 389 bool *is_v6gw) 390 { 391 struct net_device *dev = rt->dst.dev; 392 struct neighbour *neigh; 393 394 if (likely(rt->rt_gw_family == AF_INET)) { 395 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 396 } else if (rt->rt_gw_family == AF_INET6) { 397 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 398 *is_v6gw = true; 399 } else { 400 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 401 } 402 return neigh; 403 } 404 405 #endif /* _ROUTE_H */ 406