1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Definitions for the IP router. 7 * 8 * Version: @(#)route.h 1.0.4 05/27/93 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * Fixes: 13 * Alan Cox : Reformatted. Added ip_rt_local() 14 * Alan Cox : Support for TCP parameters. 15 * Alexey Kuznetsov: Major changes for new routing code. 16 * Mike McLagan : Routing by source 17 * Robert Olsson : Added rt_cache statistics 18 * 19 * This program is free software; you can redistribute it and/or 20 * modify it under the terms of the GNU General Public License 21 * as published by the Free Software Foundation; either version 22 * 2 of the License, or (at your option) any later version. 23 */ 24 #ifndef _ROUTE_H 25 #define _ROUTE_H 26 27 #include <net/dst.h> 28 #include <net/inetpeer.h> 29 #include <net/flow.h> 30 #include <net/inet_sock.h> 31 #include <net/ip_fib.h> 32 #include <net/arp.h> 33 #include <net/ndisc.h> 34 #include <linux/in_route.h> 35 #include <linux/rtnetlink.h> 36 #include <linux/rcupdate.h> 37 #include <linux/route.h> 38 #include <linux/ip.h> 39 #include <linux/cache.h> 40 #include <linux/security.h> 41 42 /* IPv4 datagram length is stored into 16bit field (tot_len) */ 43 #define IP_MAX_MTU 0xFFFFU 44 45 #define RTO_ONLINK 0x01 46 47 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE)) 48 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE)) 49 50 struct fib_nh; 51 struct fib_info; 52 struct uncached_list; 53 struct rtable { 54 struct dst_entry dst; 55 56 int rt_genid; 57 unsigned int rt_flags; 58 __u16 rt_type; 59 __u8 rt_is_input; 60 u8 rt_gw_family; 61 62 int rt_iif; 63 64 /* Info on neighbour */ 65 union { 66 __be32 rt_gw4; 67 struct in6_addr rt_gw6; 68 }; 69 70 /* Miscellaneous cached information */ 71 u32 rt_mtu_locked:1, 72 rt_pmtu:31; 73 74 struct list_head rt_uncached; 75 struct uncached_list *rt_uncached_list; 76 }; 77 78 static inline bool rt_is_input_route(const struct rtable *rt) 79 { 80 return rt->rt_is_input != 0; 81 } 82 83 static inline bool rt_is_output_route(const struct rtable *rt) 84 { 85 return rt->rt_is_input == 0; 86 } 87 88 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 89 { 90 if (rt->rt_gw_family == AF_INET) 91 return rt->rt_gw4; 92 return daddr; 93 } 94 95 struct ip_rt_acct { 96 __u32 o_bytes; 97 __u32 o_packets; 98 __u32 i_bytes; 99 __u32 i_packets; 100 }; 101 102 struct rt_cache_stat { 103 unsigned int in_slow_tot; 104 unsigned int in_slow_mc; 105 unsigned int in_no_route; 106 unsigned int in_brd; 107 unsigned int in_martian_dst; 108 unsigned int in_martian_src; 109 unsigned int out_slow_tot; 110 unsigned int out_slow_mc; 111 }; 112 113 extern struct ip_rt_acct __percpu *ip_rt_acct; 114 115 struct in_device; 116 117 int ip_rt_init(void); 118 void rt_cache_flush(struct net *net); 119 void rt_flush_dev(struct net_device *dev); 120 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 121 const struct sk_buff *skb); 122 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 123 struct fib_result *res, 124 const struct sk_buff *skb); 125 126 static inline struct rtable *__ip_route_output_key(struct net *net, 127 struct flowi4 *flp) 128 { 129 return ip_route_output_key_hash(net, flp, NULL); 130 } 131 132 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 133 const struct sock *sk); 134 struct dst_entry *ipv4_blackhole_route(struct net *net, 135 struct dst_entry *dst_orig); 136 137 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 138 { 139 return ip_route_output_flow(net, flp, NULL); 140 } 141 142 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 143 __be32 saddr, u8 tos, int oif) 144 { 145 struct flowi4 fl4 = { 146 .flowi4_oif = oif, 147 .flowi4_tos = tos, 148 .daddr = daddr, 149 .saddr = saddr, 150 }; 151 return ip_route_output_key(net, &fl4); 152 } 153 154 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 155 struct sock *sk, 156 __be32 daddr, __be32 saddr, 157 __be16 dport, __be16 sport, 158 __u8 proto, __u8 tos, int oif) 159 { 160 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 161 RT_SCOPE_UNIVERSE, proto, 162 sk ? inet_sk_flowi_flags(sk) : 0, 163 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 164 if (sk) 165 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 166 return ip_route_output_flow(net, fl4, sk); 167 } 168 169 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 170 __be32 daddr, __be32 saddr, 171 __be32 gre_key, __u8 tos, int oif) 172 { 173 memset(fl4, 0, sizeof(*fl4)); 174 fl4->flowi4_oif = oif; 175 fl4->daddr = daddr; 176 fl4->saddr = saddr; 177 fl4->flowi4_tos = tos; 178 fl4->flowi4_proto = IPPROTO_GRE; 179 fl4->fl4_gre_key = gre_key; 180 return ip_route_output_key(net, fl4); 181 } 182 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 183 u8 tos, struct net_device *dev, 184 struct in_device *in_dev, u32 *itag); 185 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 186 u8 tos, struct net_device *devin); 187 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src, 188 u8 tos, struct net_device *devin, 189 struct fib_result *res); 190 191 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 192 u8 tos, struct net_device *devin) 193 { 194 int err; 195 196 rcu_read_lock(); 197 err = ip_route_input_noref(skb, dst, src, tos, devin); 198 if (!err) { 199 skb_dst_force(skb); 200 if (!skb_dst(skb)) 201 err = -EINVAL; 202 } 203 rcu_read_unlock(); 204 205 return err; 206 } 207 208 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 209 u8 protocol); 210 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 211 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol); 212 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 213 void ip_rt_send_redirect(struct sk_buff *skb); 214 215 unsigned int inet_addr_type(struct net *net, __be32 addr); 216 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 217 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 218 __be32 addr); 219 unsigned int inet_addr_type_dev_table(struct net *net, 220 const struct net_device *dev, 221 __be32 addr); 222 void ip_rt_multicast_event(struct in_device *); 223 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 224 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 225 struct rtable *rt_dst_alloc(struct net_device *dev, 226 unsigned int flags, u16 type, 227 bool nopolicy, bool noxfrm, bool will_cache); 228 229 struct in_ifaddr; 230 void fib_add_ifaddr(struct in_ifaddr *); 231 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 232 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric); 233 234 void rt_add_uncached_list(struct rtable *rt); 235 void rt_del_uncached_list(struct rtable *rt); 236 237 static inline void ip_rt_put(struct rtable *rt) 238 { 239 /* dst_release() accepts a NULL parameter. 240 * We rely on dst being first structure in struct rtable 241 */ 242 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 243 dst_release(&rt->dst); 244 } 245 246 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 247 248 extern const __u8 ip_tos2prio[16]; 249 250 static inline char rt_tos2priority(u8 tos) 251 { 252 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 253 } 254 255 /* ip_route_connect() and ip_route_newports() work in tandem whilst 256 * binding a socket for a new outgoing connection. 257 * 258 * In order to use IPSEC properly, we must, in the end, have a 259 * route that was looked up using all available keys including source 260 * and destination ports. 261 * 262 * However, if a source port needs to be allocated (the user specified 263 * a wildcard source port) we need to obtain addressing information 264 * in order to perform that allocation. 265 * 266 * So ip_route_connect() looks up a route using wildcarded source and 267 * destination ports in the key, simply so that we can get a pair of 268 * addresses to use for port allocation. 269 * 270 * Later, once the ports are allocated, ip_route_newports() will make 271 * another route lookup if needed to make sure we catch any IPSEC 272 * rules keyed on the port information. 273 * 274 * The callers allocate the flow key on their stack, and must pass in 275 * the same flowi4 object to both the ip_route_connect() and the 276 * ip_route_newports() calls. 277 */ 278 279 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 280 u32 tos, int oif, u8 protocol, 281 __be16 sport, __be16 dport, 282 struct sock *sk) 283 { 284 __u8 flow_flags = 0; 285 286 if (inet_sk(sk)->transparent) 287 flow_flags |= FLOWI_FLAG_ANYSRC; 288 289 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 290 protocol, flow_flags, dst, src, dport, sport, 291 sk->sk_uid); 292 } 293 294 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 295 __be32 dst, __be32 src, u32 tos, 296 int oif, u8 protocol, 297 __be16 sport, __be16 dport, 298 struct sock *sk) 299 { 300 struct net *net = sock_net(sk); 301 struct rtable *rt; 302 303 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 304 sport, dport, sk); 305 306 if (!dst || !src) { 307 rt = __ip_route_output_key(net, fl4); 308 if (IS_ERR(rt)) 309 return rt; 310 ip_rt_put(rt); 311 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 312 } 313 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 314 return ip_route_output_flow(net, fl4, sk); 315 } 316 317 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 318 __be16 orig_sport, __be16 orig_dport, 319 __be16 sport, __be16 dport, 320 struct sock *sk) 321 { 322 if (sport != orig_sport || dport != orig_dport) { 323 fl4->fl4_dport = dport; 324 fl4->fl4_sport = sport; 325 ip_rt_put(rt); 326 flowi4_update_output(fl4, sk->sk_bound_dev_if, 327 RT_CONN_FLAGS(sk), fl4->daddr, 328 fl4->saddr); 329 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 330 return ip_route_output_flow(sock_net(sk), fl4, sk); 331 } 332 return rt; 333 } 334 335 static inline int inet_iif(const struct sk_buff *skb) 336 { 337 struct rtable *rt = skb_rtable(skb); 338 339 if (rt && rt->rt_iif) 340 return rt->rt_iif; 341 342 return skb->skb_iif; 343 } 344 345 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 346 { 347 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 348 struct net *net = dev_net(dst->dev); 349 350 if (hoplimit == 0) 351 hoplimit = net->ipv4.sysctl_ip_default_ttl; 352 return hoplimit; 353 } 354 355 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev, 356 __be32 daddr) 357 { 358 struct neighbour *neigh; 359 360 neigh = __ipv4_neigh_lookup_noref(dev, daddr); 361 if (unlikely(!neigh)) 362 neigh = __neigh_create(&arp_tbl, &daddr, dev, false); 363 364 return neigh; 365 } 366 367 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt, 368 struct sk_buff *skb, 369 bool *is_v6gw) 370 { 371 struct net_device *dev = rt->dst.dev; 372 struct neighbour *neigh; 373 374 if (likely(rt->rt_gw_family == AF_INET)) { 375 neigh = ip_neigh_gw4(dev, rt->rt_gw4); 376 } else if (rt->rt_gw_family == AF_INET6) { 377 neigh = ip_neigh_gw6(dev, &rt->rt_gw6); 378 *is_v6gw = true; 379 } else { 380 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr); 381 } 382 return neigh; 383 } 384 385 #endif /* _ROUTE_H */ 386