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 struct list_head rt_uncached; 70 struct uncached_list *rt_uncached_list; 71 }; 72 73 static inline bool rt_is_input_route(const struct rtable *rt) 74 { 75 return rt->rt_is_input != 0; 76 } 77 78 static inline bool rt_is_output_route(const struct rtable *rt) 79 { 80 return rt->rt_is_input == 0; 81 } 82 83 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 84 { 85 if (rt->rt_gateway) 86 return rt->rt_gateway; 87 return daddr; 88 } 89 90 struct ip_rt_acct { 91 __u32 o_bytes; 92 __u32 o_packets; 93 __u32 i_bytes; 94 __u32 i_packets; 95 }; 96 97 struct rt_cache_stat { 98 unsigned int in_slow_tot; 99 unsigned int in_slow_mc; 100 unsigned int in_no_route; 101 unsigned int in_brd; 102 unsigned int in_martian_dst; 103 unsigned int in_martian_src; 104 unsigned int out_slow_tot; 105 unsigned int out_slow_mc; 106 }; 107 108 extern struct ip_rt_acct __percpu *ip_rt_acct; 109 110 struct in_device; 111 112 int ip_rt_init(void); 113 void rt_cache_flush(struct net *net); 114 void rt_flush_dev(struct net_device *dev); 115 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp, 116 const struct sk_buff *skb); 117 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp, 118 struct fib_result *res, 119 const struct sk_buff *skb); 120 121 static inline struct rtable *__ip_route_output_key(struct net *net, 122 struct flowi4 *flp) 123 { 124 return ip_route_output_key_hash(net, flp, NULL); 125 } 126 127 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 128 const struct sock *sk); 129 struct dst_entry *ipv4_blackhole_route(struct net *net, 130 struct dst_entry *dst_orig); 131 132 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 133 { 134 return ip_route_output_flow(net, flp, NULL); 135 } 136 137 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 138 __be32 saddr, u8 tos, int oif) 139 { 140 struct flowi4 fl4 = { 141 .flowi4_oif = oif, 142 .flowi4_tos = tos, 143 .daddr = daddr, 144 .saddr = saddr, 145 }; 146 return ip_route_output_key(net, &fl4); 147 } 148 149 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 150 struct sock *sk, 151 __be32 daddr, __be32 saddr, 152 __be16 dport, __be16 sport, 153 __u8 proto, __u8 tos, int oif) 154 { 155 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 156 RT_SCOPE_UNIVERSE, proto, 157 sk ? inet_sk_flowi_flags(sk) : 0, 158 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 159 if (sk) 160 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 161 return ip_route_output_flow(net, fl4, sk); 162 } 163 164 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 165 __be32 daddr, __be32 saddr, 166 __be32 gre_key, __u8 tos, int oif) 167 { 168 memset(fl4, 0, sizeof(*fl4)); 169 fl4->flowi4_oif = oif; 170 fl4->daddr = daddr; 171 fl4->saddr = saddr; 172 fl4->flowi4_tos = tos; 173 fl4->flowi4_proto = IPPROTO_GRE; 174 fl4->fl4_gre_key = gre_key; 175 return ip_route_output_key(net, fl4); 176 } 177 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr, 178 u8 tos, struct net_device *dev, 179 struct in_device *in_dev, u32 *itag); 180 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 181 u8 tos, struct net_device *devin); 182 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src, 183 u8 tos, struct net_device *devin, 184 struct fib_result *res); 185 186 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 187 u8 tos, struct net_device *devin) 188 { 189 int err; 190 191 rcu_read_lock(); 192 err = ip_route_input_noref(skb, dst, src, tos, devin); 193 if (!err) { 194 skb_dst_force(skb); 195 if (!skb_dst(skb)) 196 err = -EINVAL; 197 } 198 rcu_read_unlock(); 199 200 return err; 201 } 202 203 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 204 u32 mark, u8 protocol, int flow_flags); 205 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 206 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 207 u8 protocol, int flow_flags); 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 #endif /* _ROUTE_H */ 352