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