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 fib_nh; 47 struct fib_info; 48 struct uncached_list; 49 struct rtable { 50 struct dst_entry dst; 51 52 int rt_genid; 53 unsigned int rt_flags; 54 __u16 rt_type; 55 __u8 rt_is_input; 56 u8 rt_gw_family; 57 58 int rt_iif; 59 60 /* Info on neighbour */ 61 union { 62 __be32 rt_gw4; 63 struct in6_addr rt_gw6; 64 }; 65 66 /* Miscellaneous cached information */ 67 u32 rt_mtu_locked:1, 68 rt_pmtu:31; 69 70 struct list_head rt_uncached; 71 struct uncached_list *rt_uncached_list; 72 }; 73 74 static inline bool rt_is_input_route(const struct rtable *rt) 75 { 76 return rt->rt_is_input != 0; 77 } 78 79 static inline bool rt_is_output_route(const struct rtable *rt) 80 { 81 return rt->rt_is_input == 0; 82 } 83 84 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 85 { 86 if (rt->rt_gw_family == AF_INET) 87 return rt->rt_gw4; 88 return daddr; 89 } 90 91 struct ip_rt_acct { 92 __u32 o_bytes; 93 __u32 o_packets; 94 __u32 i_bytes; 95 __u32 i_packets; 96 }; 97 98 struct rt_cache_stat { 99 unsigned int in_slow_tot; 100 unsigned int in_slow_mc; 101 unsigned int in_no_route; 102 unsigned int in_brd; 103 unsigned int in_martian_dst; 104 unsigned int in_martian_src; 105 unsigned int out_slow_tot; 106 unsigned int out_slow_mc; 107 }; 108 109 extern struct ip_rt_acct __percpu *ip_rt_acct; 110 111 struct in_device; 112 113 int ip_rt_init(void); 114 void rt_cache_flush(struct net *net); 115 void rt_flush_dev(struct net_device *dev); 116 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 117 const struct sk_buff *skb); 118 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 119 struct fib_result *res, 120 const struct sk_buff *skb); 121 122 static inline struct rtable *__ip_route_output_key(struct net *net, 123 struct flowi4 *flp) 124 { 125 return ip_route_output_key_hash(net, flp, NULL); 126 } 127 128 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 129 const struct sock *sk); 130 struct dst_entry *ipv4_blackhole_route(struct net *net, 131 struct dst_entry *dst_orig); 132 133 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 134 { 135 return ip_route_output_flow(net, flp, NULL); 136 } 137 138 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 139 __be32 saddr, u8 tos, int oif) 140 { 141 struct flowi4 fl4 = { 142 .flowi4_oif = oif, 143 .flowi4_tos = tos, 144 .daddr = daddr, 145 .saddr = saddr, 146 }; 147 return ip_route_output_key(net, &fl4); 148 } 149 150 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 151 struct sock *sk, 152 __be32 daddr, __be32 saddr, 153 __be16 dport, __be16 sport, 154 __u8 proto, __u8 tos, int oif) 155 { 156 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 157 RT_SCOPE_UNIVERSE, proto, 158 sk ? inet_sk_flowi_flags(sk) : 0, 159 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 160 if (sk) 161 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 162 return ip_route_output_flow(net, fl4, sk); 163 } 164 165 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 166 __be32 daddr, __be32 saddr, 167 __be32 gre_key, __u8 tos, int oif) 168 { 169 memset(fl4, 0, sizeof(*fl4)); 170 fl4->flowi4_oif = oif; 171 fl4->daddr = daddr; 172 fl4->saddr = saddr; 173 fl4->flowi4_tos = tos; 174 fl4->flowi4_proto = IPPROTO_GRE; 175 fl4->fl4_gre_key = gre_key; 176 return ip_route_output_key(net, fl4); 177 } 178 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 179 u8 tos, struct net_device *dev, 180 struct in_device *in_dev, u32 *itag); 181 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 182 u8 tos, struct net_device *devin); 183 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src, 184 u8 tos, struct net_device *devin, 185 struct fib_result *res); 186 187 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 188 u8 tos, struct net_device *devin) 189 { 190 int err; 191 192 rcu_read_lock(); 193 err = ip_route_input_noref(skb, dst, src, tos, devin); 194 if (!err) { 195 skb_dst_force(skb); 196 if (!skb_dst(skb)) 197 err = -EINVAL; 198 } 199 rcu_read_unlock(); 200 201 return err; 202 } 203 204 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 205 u8 protocol); 206 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 207 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 208 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 209 void ip_rt_send_redirect(struct sk_buff *skb); 210 211 unsigned int inet_addr_type(struct net *net, __be32 addr); 212 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 213 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 214 __be32 addr); 215 unsigned int inet_addr_type_dev_table(struct net *net, 216 const struct net_device *dev, 217 __be32 addr); 218 void ip_rt_multicast_event(struct in_device *); 219 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 220 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 221 struct rtable *rt_dst_alloc(struct net_device *dev, 222 unsigned int flags, u16 type, 223 bool nopolicy, bool noxfrm, bool will_cache); 224 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt); 225 226 struct in_ifaddr; 227 void fib_add_ifaddr(struct in_ifaddr *); 228 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 229 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 230 231 void rt_add_uncached_list(struct rtable *rt); 232 void rt_del_uncached_list(struct rtable *rt); 233 234 static inline void ip_rt_put(struct rtable *rt) 235 { 236 /* dst_release() accepts a NULL parameter. 237 * We rely on dst being first structure in struct rtable 238 */ 239 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 240 dst_release(&rt->dst); 241 } 242 243 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 244 245 extern const __u8 ip_tos2prio[16]; 246 247 static inline char rt_tos2priority(u8 tos) 248 { 249 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 250 } 251 252 /* ip_route_connect() and ip_route_newports() work in tandem whilst 253 * binding a socket for a new outgoing connection. 254 * 255 * In order to use IPSEC properly, we must, in the end, have a 256 * route that was looked up using all available keys including source 257 * and destination ports. 258 * 259 * However, if a source port needs to be allocated (the user specified 260 * a wildcard source port) we need to obtain addressing information 261 * in order to perform that allocation. 262 * 263 * So ip_route_connect() looks up a route using wildcarded source and 264 * destination ports in the key, simply so that we can get a pair of 265 * addresses to use for port allocation. 266 * 267 * Later, once the ports are allocated, ip_route_newports() will make 268 * another route lookup if needed to make sure we catch any IPSEC 269 * rules keyed on the port information. 270 * 271 * The callers allocate the flow key on their stack, and must pass in 272 * the same flowi4 object to both the ip_route_connect() and the 273 * ip_route_newports() calls. 274 */ 275 276 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 277 u32 tos, int oif, u8 protocol, 278 __be16 sport, __be16 dport, 279 struct sock *sk) 280 { 281 __u8 flow_flags = 0; 282 283 if (inet_sk(sk)->transparent) 284 flow_flags |= FLOWI_FLAG_ANYSRC; 285 286 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 287 protocol, flow_flags, dst, src, dport, sport, 288 sk->sk_uid); 289 } 290 291 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 292 __be32 dst, __be32 src, u32 tos, 293 int oif, u8 protocol, 294 __be16 sport, __be16 dport, 295 struct sock *sk) 296 { 297 struct net *net = sock_net(sk); 298 struct rtable *rt; 299 300 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 301 sport, dport, sk); 302 303 if (!dst || !src) { 304 rt = __ip_route_output_key(net, fl4); 305 if (IS_ERR(rt)) 306 return rt; 307 ip_rt_put(rt); 308 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 309 } 310 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 311 return ip_route_output_flow(net, fl4, sk); 312 } 313 314 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 315 __be16 orig_sport, __be16 orig_dport, 316 __be16 sport, __be16 dport, 317 struct sock *sk) 318 { 319 if (sport != orig_sport || dport != orig_dport) { 320 fl4->fl4_dport = dport; 321 fl4->fl4_sport = sport; 322 ip_rt_put(rt); 323 flowi4_update_output(fl4, sk->sk_bound_dev_if, 324 RT_CONN_FLAGS(sk), fl4->daddr, 325 fl4->saddr); 326 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 327 return ip_route_output_flow(sock_net(sk), fl4, sk); 328 } 329 return rt; 330 } 331 332 static inline int inet_iif(const struct sk_buff *skb) 333 { 334 struct rtable *rt = skb_rtable(skb); 335 336 if (rt && rt->rt_iif) 337 return rt->rt_iif; 338 339 return skb->skb_iif; 340 } 341 342 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 343 { 344 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 345 struct net *net = dev_net(dst->dev); 346 347 if (hoplimit == 0) 348 hoplimit = net->ipv4.sysctl_ip_default_ttl; 349 return hoplimit; 350 } 351 352 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 353 __be32 daddr) 354 { 355 struct neighbour *neigh; 356 357 neigh = __ipv4_neigh_lookup_noref(dev, daddr); 358 if (unlikely(!neigh)) 359 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 360 361 return neigh; 362 } 363 364 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 365 struct sk_buff *skb, 366 bool *is_v6gw) 367 { 368 struct net_device *dev = rt->dst.dev; 369 struct neighbour *neigh; 370 371 if (likely(rt->rt_gw_family == AF_INET)) { 372 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 373 } else if (rt->rt_gw_family == AF_INET6) { 374 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 375 *is_v6gw = true; 376 } else { 377 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 378 } 379 return neigh; 380 } 381 382 #endif /* _ROUTE_H */ 383