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