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/l3mdev.h> 33 #include <linux/in_route.h> 34 #include <linux/rtnetlink.h> 35 #include <linux/rcupdate.h> 36 #include <linux/route.h> 37 #include <linux/ip.h> 38 #include <linux/cache.h> 39 #include <linux/security.h> 40 41 /* IPv4 datagram length is stored into 16bit field (tot_len) */ 42 #define IP_MAX_MTU 0xFFFFU 43 44 #define RTO_ONLINK 0x01 45 46 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE)) 47 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE)) 48 49 struct fib_nh; 50 struct fib_info; 51 struct uncached_list; 52 struct rtable { 53 struct dst_entry dst; 54 55 int rt_genid; 56 unsigned int rt_flags; 57 __u16 rt_type; 58 __u8 rt_is_input; 59 __u8 rt_uses_gateway; 60 61 int rt_iif; 62 63 /* Info on neighbour */ 64 __be32 rt_gateway; 65 66 /* Miscellaneous cached information */ 67 u32 rt_pmtu; 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 *, struct flowi4 *flp, 118 int mp_hash); 119 120 static inline struct rtable *__ip_route_output_key(struct net *net, 121 struct flowi4 *flp) 122 { 123 return __ip_route_output_key_hash(net, flp, -1); 124 } 125 126 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 127 const struct sock *sk); 128 struct dst_entry *ipv4_blackhole_route(struct net *net, 129 struct dst_entry *dst_orig); 130 131 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 132 { 133 return ip_route_output_flow(net, flp, NULL); 134 } 135 136 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 137 __be32 saddr, u8 tos, int oif) 138 { 139 struct flowi4 fl4 = { 140 .flowi4_oif = oif, 141 .flowi4_tos = tos, 142 .daddr = daddr, 143 .saddr = saddr, 144 }; 145 return ip_route_output_key(net, &fl4); 146 } 147 148 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 149 struct sock *sk, 150 __be32 daddr, __be32 saddr, 151 __be16 dport, __be16 sport, 152 __u8 proto, __u8 tos, int oif) 153 { 154 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 155 RT_SCOPE_UNIVERSE, proto, 156 sk ? inet_sk_flowi_flags(sk) : 0, 157 daddr, saddr, dport, sport); 158 if (sk) 159 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 160 return ip_route_output_flow(net, fl4, sk); 161 } 162 163 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 164 __be32 daddr, __be32 saddr, 165 __be32 gre_key, __u8 tos, int oif) 166 { 167 memset(fl4, 0, sizeof(*fl4)); 168 fl4->flowi4_oif = oif; 169 fl4->daddr = daddr; 170 fl4->saddr = saddr; 171 fl4->flowi4_tos = tos; 172 fl4->flowi4_proto = IPPROTO_GRE; 173 fl4->fl4_gre_key = gre_key; 174 return ip_route_output_key(net, fl4); 175 } 176 177 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 178 u8 tos, struct net_device *devin); 179 180 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 181 u8 tos, struct net_device *devin) 182 { 183 int err; 184 185 rcu_read_lock(); 186 err = ip_route_input_noref(skb, dst, src, tos, devin); 187 if (!err) 188 skb_dst_force(skb); 189 rcu_read_unlock(); 190 191 return err; 192 } 193 194 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 195 u32 mark, u8 protocol, int flow_flags); 196 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 197 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 198 u8 protocol, int flow_flags); 199 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 200 void ip_rt_send_redirect(struct sk_buff *skb); 201 202 unsigned int inet_addr_type(struct net *net, __be32 addr); 203 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 204 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 205 __be32 addr); 206 unsigned int inet_addr_type_dev_table(struct net *net, 207 const struct net_device *dev, 208 __be32 addr); 209 void ip_rt_multicast_event(struct in_device *); 210 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg); 211 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 212 struct rtable *rt_dst_alloc(struct net_device *dev, 213 unsigned int flags, u16 type, 214 bool nopolicy, bool noxfrm, bool will_cache); 215 216 struct in_ifaddr; 217 void fib_add_ifaddr(struct in_ifaddr *); 218 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 219 220 static inline void ip_rt_put(struct rtable *rt) 221 { 222 /* dst_release() accepts a NULL parameter. 223 * We rely on dst being first structure in struct rtable 224 */ 225 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 226 dst_release(&rt->dst); 227 } 228 229 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 230 231 extern const __u8 ip_tos2prio[16]; 232 233 static inline char rt_tos2priority(u8 tos) 234 { 235 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 236 } 237 238 /* ip_route_connect() and ip_route_newports() work in tandem whilst 239 * binding a socket for a new outgoing connection. 240 * 241 * In order to use IPSEC properly, we must, in the end, have a 242 * route that was looked up using all available keys including source 243 * and destination ports. 244 * 245 * However, if a source port needs to be allocated (the user specified 246 * a wildcard source port) we need to obtain addressing information 247 * in order to perform that allocation. 248 * 249 * So ip_route_connect() looks up a route using wildcarded source and 250 * destination ports in the key, simply so that we can get a pair of 251 * addresses to use for port allocation. 252 * 253 * Later, once the ports are allocated, ip_route_newports() will make 254 * another route lookup if needed to make sure we catch any IPSEC 255 * rules keyed on the port information. 256 * 257 * The callers allocate the flow key on their stack, and must pass in 258 * the same flowi4 object to both the ip_route_connect() and the 259 * ip_route_newports() calls. 260 */ 261 262 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 263 u32 tos, int oif, u8 protocol, 264 __be16 sport, __be16 dport, 265 struct sock *sk) 266 { 267 __u8 flow_flags = 0; 268 269 if (inet_sk(sk)->transparent) 270 flow_flags |= FLOWI_FLAG_ANYSRC; 271 272 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 273 protocol, flow_flags, dst, src, dport, sport); 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 (!src && oif) { 289 int rc; 290 291 rc = l3mdev_get_saddr(net, oif, fl4); 292 if (rc < 0) 293 return ERR_PTR(rc); 294 295 src = fl4->saddr; 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