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); 224 225 struct in_ifaddr; 226 void fib_add_ifaddr(struct in_ifaddr *); 227 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 228 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 229 230 void rt_add_uncached_list(struct rtable *rt); 231 void rt_del_uncached_list(struct rtable *rt); 232 233 static inline void ip_rt_put(struct rtable *rt) 234 { 235 /* dst_release() accepts a NULL parameter. 236 * We rely on dst being first structure in struct rtable 237 */ 238 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 239 dst_release(&rt->dst); 240 } 241 242 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 243 244 extern const __u8 ip_tos2prio[16]; 245 246 static inline char rt_tos2priority(u8 tos) 247 { 248 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 249 } 250 251 /* ip_route_connect() and ip_route_newports() work in tandem whilst 252 * binding a socket for a new outgoing connection. 253 * 254 * In order to use IPSEC properly, we must, in the end, have a 255 * route that was looked up using all available keys including source 256 * and destination ports. 257 * 258 * However, if a source port needs to be allocated (the user specified 259 * a wildcard source port) we need to obtain addressing information 260 * in order to perform that allocation. 261 * 262 * So ip_route_connect() looks up a route using wildcarded source and 263 * destination ports in the key, simply so that we can get a pair of 264 * addresses to use for port allocation. 265 * 266 * Later, once the ports are allocated, ip_route_newports() will make 267 * another route lookup if needed to make sure we catch any IPSEC 268 * rules keyed on the port information. 269 * 270 * The callers allocate the flow key on their stack, and must pass in 271 * the same flowi4 object to both the ip_route_connect() and the 272 * ip_route_newports() calls. 273 */ 274 275 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 276 u32 tos, int oif, u8 protocol, 277 __be16 sport, __be16 dport, 278 struct sock *sk) 279 { 280 __u8 flow_flags = 0; 281 282 if (inet_sk(sk)->transparent) 283 flow_flags |= FLOWI_FLAG_ANYSRC; 284 285 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 286 protocol, flow_flags, dst, src, dport, sport, 287 sk->sk_uid); 288 } 289 290 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 291 __be32 dst, __be32 src, u32 tos, 292 int oif, u8 protocol, 293 __be16 sport, __be16 dport, 294 struct sock *sk) 295 { 296 struct net *net = sock_net(sk); 297 struct rtable *rt; 298 299 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 300 sport, dport, sk); 301 302 if (!dst || !src) { 303 rt = __ip_route_output_key(net, fl4); 304 if (IS_ERR(rt)) 305 return rt; 306 ip_rt_put(rt); 307 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 308 } 309 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 310 return ip_route_output_flow(net, fl4, sk); 311 } 312 313 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 314 __be16 orig_sport, __be16 orig_dport, 315 __be16 sport, __be16 dport, 316 struct sock *sk) 317 { 318 if (sport != orig_sport || dport != orig_dport) { 319 fl4->fl4_dport = dport; 320 fl4->fl4_sport = sport; 321 ip_rt_put(rt); 322 flowi4_update_output(fl4, sk->sk_bound_dev_if, 323 RT_CONN_FLAGS(sk), fl4->daddr, 324 fl4->saddr); 325 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 326 return ip_route_output_flow(sock_net(sk), fl4, sk); 327 } 328 return rt; 329 } 330 331 static inline int inet_iif(const struct sk_buff *skb) 332 { 333 struct rtable *rt = skb_rtable(skb); 334 335 if (rt && rt->rt_iif) 336 return rt->rt_iif; 337 338 return skb->skb_iif; 339 } 340 341 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 342 { 343 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 344 struct net *net = dev_net(dst->dev); 345 346 if (hoplimit == 0) 347 hoplimit = net->ipv4.sysctl_ip_default_ttl; 348 return hoplimit; 349 } 350 351 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 352 __be32 daddr) 353 { 354 struct neighbour *neigh; 355 356 neigh = __ipv4_neigh_lookup_noref(dev, daddr); 357 if (unlikely(!neigh)) 358 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 359 360 return neigh; 361 } 362 363 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 364 struct sk_buff *skb, 365 bool *is_v6gw) 366 { 367 struct net_device *dev = rt->dst.dev; 368 struct neighbour *neigh; 369 370 if (likely(rt->rt_gw_family == AF_INET)) { 371 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 372 } else if (rt->rt_gw_family == AF_INET6) { 373 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 374 *is_v6gw = true; 375 } else { 376 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 377 } 378 return neigh; 379 } 380 381 #endif /* _ROUTE_H */ 382