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 <linux/in_route.h> 33 #include <linux/rtnetlink.h> 34 #include <linux/rcupdate.h> 35 #include <linux/route.h> 36 #include <linux/ip.h> 37 #include <linux/cache.h> 38 #include <linux/security.h> 39 40 /* IPv4 datagram length is stored into 16bit field (tot_len) */ 41 #define IP_MAX_MTU 0xFFFFU 42 43 #define RTO_ONLINK 0x01 44 45 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE)) 46 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE)) 47 48 struct fib_nh; 49 struct fib_info; 50 struct uncached_list; 51 struct rtable { 52 struct dst_entry dst; 53 54 int rt_genid; 55 unsigned int rt_flags; 56 __u16 rt_type; 57 __u8 rt_is_input; 58 __u8 rt_uses_gateway; 59 60 int rt_iif; 61 62 /* Info on neighbour */ 63 __be32 rt_gateway; 64 65 /* Miscellaneous cached information */ 66 u32 rt_mtu_locked:1, 67 rt_pmtu:31; 68 69 u32 rt_table_id; 70 71 struct list_head rt_uncached; 72 struct uncached_list *rt_uncached_list; 73 }; 74 75 static inline bool rt_is_input_route(const struct rtable *rt) 76 { 77 return rt->rt_is_input != 0; 78 } 79 80 static inline bool rt_is_output_route(const struct rtable *rt) 81 { 82 return rt->rt_is_input == 0; 83 } 84 85 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 86 { 87 if (rt->rt_gateway) 88 return rt->rt_gateway; 89 return daddr; 90 } 91 92 struct ip_rt_acct { 93 __u32 o_bytes; 94 __u32 o_packets; 95 __u32 i_bytes; 96 __u32 i_packets; 97 }; 98 99 struct rt_cache_stat { 100 unsigned int in_slow_tot; 101 unsigned int in_slow_mc; 102 unsigned int in_no_route; 103 unsigned int in_brd; 104 unsigned int in_martian_dst; 105 unsigned int in_martian_src; 106 unsigned int out_slow_tot; 107 unsigned int out_slow_mc; 108 }; 109 110 extern struct ip_rt_acct __percpu *ip_rt_acct; 111 112 struct in_device; 113 114 int ip_rt_init(void); 115 void rt_cache_flush(struct net *net); 116 void rt_flush_dev(struct net_device *dev); 117 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 118 const struct sk_buff *skb); 119 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 120 struct fib_result *res, 121 const struct sk_buff *skb); 122 123 static inline struct rtable *__ip_route_output_key(struct net *net, 124 struct flowi4 *flp) 125 { 126 return ip_route_output_key_hash(net, flp, NULL); 127 } 128 129 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 130 const struct sock *sk); 131 struct dst_entry *ipv4_blackhole_route(struct net *net, 132 struct dst_entry *dst_orig); 133 134 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 135 { 136 return ip_route_output_flow(net, flp, NULL); 137 } 138 139 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 140 __be32 saddr, u8 tos, int oif) 141 { 142 struct flowi4 fl4 = { 143 .flowi4_oif = oif, 144 .flowi4_tos = tos, 145 .daddr = daddr, 146 .saddr = saddr, 147 }; 148 return ip_route_output_key(net, &fl4); 149 } 150 151 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 152 struct sock *sk, 153 __be32 daddr, __be32 saddr, 154 __be16 dport, __be16 sport, 155 __u8 proto, __u8 tos, int oif) 156 { 157 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 158 RT_SCOPE_UNIVERSE, proto, 159 sk ? inet_sk_flowi_flags(sk) : 0, 160 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 161 if (sk) 162 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 163 return ip_route_output_flow(net, fl4, sk); 164 } 165 166 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 167 __be32 daddr, __be32 saddr, 168 __be32 gre_key, __u8 tos, int oif) 169 { 170 memset(fl4, 0, sizeof(*fl4)); 171 fl4->flowi4_oif = oif; 172 fl4->daddr = daddr; 173 fl4->saddr = saddr; 174 fl4->flowi4_tos = tos; 175 fl4->flowi4_proto = IPPROTO_GRE; 176 fl4->fl4_gre_key = gre_key; 177 return ip_route_output_key(net, fl4); 178 } 179 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 180 u8 tos, struct net_device *dev, 181 struct in_device *in_dev, u32 *itag); 182 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 183 u8 tos, struct net_device *devin); 184 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src, 185 u8 tos, struct net_device *devin, 186 struct fib_result *res); 187 188 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 189 u8 tos, struct net_device *devin) 190 { 191 int err; 192 193 rcu_read_lock(); 194 err = ip_route_input_noref(skb, dst, src, tos, devin); 195 if (!err) { 196 skb_dst_force(skb); 197 if (!skb_dst(skb)) 198 err = -EINVAL; 199 } 200 rcu_read_unlock(); 201 202 return err; 203 } 204 205 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 206 u32 mark, u8 protocol, int flow_flags); 207 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 208 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 209 u8 protocol, int flow_flags); 210 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 211 void ip_rt_send_redirect(struct sk_buff *skb); 212 213 unsigned int inet_addr_type(struct net *net, __be32 addr); 214 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 215 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 216 __be32 addr); 217 unsigned int inet_addr_type_dev_table(struct net *net, 218 const struct net_device *dev, 219 __be32 addr); 220 void ip_rt_multicast_event(struct in_device *); 221 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt); 222 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 223 struct rtable *rt_dst_alloc(struct net_device *dev, 224 unsigned int flags, u16 type, 225 bool nopolicy, bool noxfrm, bool will_cache); 226 227 struct in_ifaddr; 228 void fib_add_ifaddr(struct in_ifaddr *); 229 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 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 #endif /* _ROUTE_H */ 353