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); 118 119 static inline struct rtable *__ip_route_output_key(struct net *net, 120 struct flowi4 *flp) 121 { 122 return __ip_route_output_key_hash(net, flp, NULL); 123 } 124 125 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 126 const struct sock *sk); 127 struct dst_entry *ipv4_blackhole_route(struct net *net, 128 struct dst_entry *dst_orig); 129 130 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 131 { 132 return ip_route_output_flow(net, flp, NULL); 133 } 134 135 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 136 __be32 saddr, u8 tos, int oif) 137 { 138 struct flowi4 fl4 = { 139 .flowi4_oif = oif, 140 .flowi4_tos = tos, 141 .daddr = daddr, 142 .saddr = saddr, 143 }; 144 return ip_route_output_key(net, &fl4); 145 } 146 147 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 148 struct sock *sk, 149 __be32 daddr, __be32 saddr, 150 __be16 dport, __be16 sport, 151 __u8 proto, __u8 tos, int oif) 152 { 153 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 154 RT_SCOPE_UNIVERSE, proto, 155 sk ? inet_sk_flowi_flags(sk) : 0, 156 daddr, saddr, dport, sport, sock_net_uid(net, sk)); 157 if (sk) 158 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 159 return ip_route_output_flow(net, fl4, sk); 160 } 161 162 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 163 __be32 daddr, __be32 saddr, 164 __be32 gre_key, __u8 tos, int oif) 165 { 166 memset(fl4, 0, sizeof(*fl4)); 167 fl4->flowi4_oif = oif; 168 fl4->daddr = daddr; 169 fl4->saddr = saddr; 170 fl4->flowi4_tos = tos; 171 fl4->flowi4_proto = IPPROTO_GRE; 172 fl4->fl4_gre_key = gre_key; 173 return ip_route_output_key(net, fl4); 174 } 175 176 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 177 u8 tos, struct net_device *devin); 178 179 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 180 u8 tos, struct net_device *devin) 181 { 182 int err; 183 184 rcu_read_lock(); 185 err = ip_route_input_noref(skb, dst, src, tos, devin); 186 if (!err) 187 skb_dst_force(skb); 188 rcu_read_unlock(); 189 190 return err; 191 } 192 193 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 194 u32 mark, u8 protocol, int flow_flags); 195 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 196 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 197 u8 protocol, int flow_flags); 198 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 199 void ip_rt_send_redirect(struct sk_buff *skb); 200 201 unsigned int inet_addr_type(struct net *net, __be32 addr); 202 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 203 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 204 __be32 addr); 205 unsigned int inet_addr_type_dev_table(struct net *net, 206 const struct net_device *dev, 207 __be32 addr); 208 void ip_rt_multicast_event(struct in_device *); 209 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg); 210 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 211 struct rtable *rt_dst_alloc(struct net_device *dev, 212 unsigned int flags, u16 type, 213 bool nopolicy, bool noxfrm, bool will_cache); 214 215 struct in_ifaddr; 216 void fib_add_ifaddr(struct in_ifaddr *); 217 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 218 219 static inline void ip_rt_put(struct rtable *rt) 220 { 221 /* dst_release() accepts a NULL parameter. 222 * We rely on dst being first structure in struct rtable 223 */ 224 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 225 dst_release(&rt->dst); 226 } 227 228 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 229 230 extern const __u8 ip_tos2prio[16]; 231 232 static inline char rt_tos2priority(u8 tos) 233 { 234 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 235 } 236 237 /* ip_route_connect() and ip_route_newports() work in tandem whilst 238 * binding a socket for a new outgoing connection. 239 * 240 * In order to use IPSEC properly, we must, in the end, have a 241 * route that was looked up using all available keys including source 242 * and destination ports. 243 * 244 * However, if a source port needs to be allocated (the user specified 245 * a wildcard source port) we need to obtain addressing information 246 * in order to perform that allocation. 247 * 248 * So ip_route_connect() looks up a route using wildcarded source and 249 * destination ports in the key, simply so that we can get a pair of 250 * addresses to use for port allocation. 251 * 252 * Later, once the ports are allocated, ip_route_newports() will make 253 * another route lookup if needed to make sure we catch any IPSEC 254 * rules keyed on the port information. 255 * 256 * The callers allocate the flow key on their stack, and must pass in 257 * the same flowi4 object to both the ip_route_connect() and the 258 * ip_route_newports() calls. 259 */ 260 261 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 262 u32 tos, int oif, u8 protocol, 263 __be16 sport, __be16 dport, 264 struct sock *sk) 265 { 266 __u8 flow_flags = 0; 267 268 if (inet_sk(sk)->transparent) 269 flow_flags |= FLOWI_FLAG_ANYSRC; 270 271 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 272 protocol, flow_flags, dst, src, dport, sport, 273 sk->sk_uid); 274 } 275 276 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 277 __be32 dst, __be32 src, u32 tos, 278 int oif, u8 protocol, 279 __be16 sport, __be16 dport, 280 struct sock *sk) 281 { 282 struct net *net = sock_net(sk); 283 struct rtable *rt; 284 285 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 286 sport, dport, sk); 287 288 if (!dst || !src) { 289 rt = __ip_route_output_key(net, fl4); 290 if (IS_ERR(rt)) 291 return rt; 292 ip_rt_put(rt); 293 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 294 } 295 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 296 return ip_route_output_flow(net, fl4, sk); 297 } 298 299 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 300 __be16 orig_sport, __be16 orig_dport, 301 __be16 sport, __be16 dport, 302 struct sock *sk) 303 { 304 if (sport != orig_sport || dport != orig_dport) { 305 fl4->fl4_dport = dport; 306 fl4->fl4_sport = sport; 307 ip_rt_put(rt); 308 flowi4_update_output(fl4, sk->sk_bound_dev_if, 309 RT_CONN_FLAGS(sk), fl4->daddr, 310 fl4->saddr); 311 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 312 return ip_route_output_flow(sock_net(sk), fl4, sk); 313 } 314 return rt; 315 } 316 317 static inline int inet_iif(const struct sk_buff *skb) 318 { 319 struct rtable *rt = skb_rtable(skb); 320 321 if (rt && rt->rt_iif) 322 return rt->rt_iif; 323 324 return skb->skb_iif; 325 } 326 327 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 328 { 329 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 330 struct net *net = dev_net(dst->dev); 331 332 if (hoplimit == 0) 333 hoplimit = net->ipv4.sysctl_ip_default_ttl; 334 return hoplimit; 335 } 336 337 #endif /* _ROUTE_H */ 338