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_pmtu; 67 68 u32 rt_table_id; 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_gateway) 87 return rt->rt_gateway; 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 } 178 179 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 180 u8 tos, struct net_device *devin); 181 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src, 182 u8 tos, struct net_device *devin, 183 struct fib_result *res); 184 185 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 186 u8 tos, struct net_device *devin) 187 { 188 int err; 189 190 rcu_read_lock(); 191 err = ip_route_input_noref(skb, dst, src, tos, devin); 192 if (!err) { 193 skb_dst_force_safe(skb); 194 if (!skb_dst(skb)) 195 err = -EINVAL; 196 } 197 rcu_read_unlock(); 198 199 return err; 200 } 201 202 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 203 u32 mark, u8 protocol, int flow_flags); 204 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 205 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 206 u8 protocol, int flow_flags); 207 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 208 void ip_rt_send_redirect(struct sk_buff *skb); 209 210 unsigned int inet_addr_type(struct net *net, __be32 addr); 211 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 212 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 213 __be32 addr); 214 unsigned int inet_addr_type_dev_table(struct net *net, 215 const struct net_device *dev, 216 __be32 addr); 217 void ip_rt_multicast_event(struct in_device *); 218 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg); 219 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 220 struct rtable *rt_dst_alloc(struct net_device *dev, 221 unsigned int flags, u16 type, 222 bool nopolicy, bool noxfrm, bool will_cache); 223 224 struct in_ifaddr; 225 void fib_add_ifaddr(struct in_ifaddr *); 226 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 227 228 static inline void ip_rt_put(struct rtable *rt) 229 { 230 /* dst_release() accepts a NULL parameter. 231 * We rely on dst being first structure in struct rtable 232 */ 233 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 234 dst_release(&rt->dst); 235 } 236 237 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 238 239 extern const __u8 ip_tos2prio[16]; 240 241 static inline char rt_tos2priority(u8 tos) 242 { 243 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 244 } 245 246 /* ip_route_connect() and ip_route_newports() work in tandem whilst 247 * binding a socket for a new outgoing connection. 248 * 249 * In order to use IPSEC properly, we must, in the end, have a 250 * route that was looked up using all available keys including source 251 * and destination ports. 252 * 253 * However, if a source port needs to be allocated (the user specified 254 * a wildcard source port) we need to obtain addressing information 255 * in order to perform that allocation. 256 * 257 * So ip_route_connect() looks up a route using wildcarded source and 258 * destination ports in the key, simply so that we can get a pair of 259 * addresses to use for port allocation. 260 * 261 * Later, once the ports are allocated, ip_route_newports() will make 262 * another route lookup if needed to make sure we catch any IPSEC 263 * rules keyed on the port information. 264 * 265 * The callers allocate the flow key on their stack, and must pass in 266 * the same flowi4 object to both the ip_route_connect() and the 267 * ip_route_newports() calls. 268 */ 269 270 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 271 u32 tos, int oif, u8 protocol, 272 __be16 sport, __be16 dport, 273 struct sock *sk) 274 { 275 __u8 flow_flags = 0; 276 277 if (inet_sk(sk)->transparent) 278 flow_flags |= FLOWI_FLAG_ANYSRC; 279 280 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 281 protocol, flow_flags, dst, src, dport, sport, 282 sk->sk_uid); 283 } 284 285 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 286 __be32 dst, __be32 src, u32 tos, 287 int oif, u8 protocol, 288 __be16 sport, __be16 dport, 289 struct sock *sk) 290 { 291 struct net *net = sock_net(sk); 292 struct rtable *rt; 293 294 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 295 sport, dport, sk); 296 297 if (!dst || !src) { 298 rt = __ip_route_output_key(net, fl4); 299 if (IS_ERR(rt)) 300 return rt; 301 ip_rt_put(rt); 302 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 303 } 304 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 305 return ip_route_output_flow(net, fl4, sk); 306 } 307 308 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 309 __be16 orig_sport, __be16 orig_dport, 310 __be16 sport, __be16 dport, 311 struct sock *sk) 312 { 313 if (sport != orig_sport || dport != orig_dport) { 314 fl4->fl4_dport = dport; 315 fl4->fl4_sport = sport; 316 ip_rt_put(rt); 317 flowi4_update_output(fl4, sk->sk_bound_dev_if, 318 RT_CONN_FLAGS(sk), fl4->daddr, 319 fl4->saddr); 320 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 321 return ip_route_output_flow(sock_net(sk), fl4, sk); 322 } 323 return rt; 324 } 325 326 static inline int inet_iif(const struct sk_buff *skb) 327 { 328 struct rtable *rt = skb_rtable(skb); 329 330 if (rt && rt->rt_iif) 331 return rt->rt_iif; 332 333 return skb->skb_iif; 334 } 335 336 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 337 { 338 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 339 struct net *net = dev_net(dst->dev); 340 341 if (hoplimit == 0) 342 hoplimit = net->ipv4.sysctl_ip_default_ttl; 343 return hoplimit; 344 } 345 346 #endif /* _ROUTE_H */ 347