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 <linux/in_route.h> 32 #include <linux/rtnetlink.h> 33 #include <linux/rcupdate.h> 34 #include <linux/route.h> 35 #include <linux/ip.h> 36 #include <linux/cache.h> 37 #include <linux/security.h> 38 39 /* IPv4 datagram length is stored into 16bit field (tot_len) */ 40 #define IP_MAX_MTU 0xFFFFU 41 42 #define RTO_ONLINK 0x01 43 44 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE)) 45 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE)) 46 47 struct fib_nh; 48 struct fib_info; 49 struct uncached_list; 50 struct rtable { 51 struct dst_entry dst; 52 53 int rt_genid; 54 unsigned int rt_flags; 55 __u16 rt_type; 56 __u8 rt_is_input; 57 __u8 rt_uses_gateway; 58 59 int rt_iif; 60 61 /* Info on neighbour */ 62 __be32 rt_gateway; 63 64 /* Miscellaneous cached information */ 65 u32 rt_pmtu; 66 67 struct list_head rt_uncached; 68 struct uncached_list *rt_uncached_list; 69 }; 70 71 static inline bool rt_is_input_route(const struct rtable *rt) 72 { 73 return rt->rt_is_input != 0; 74 } 75 76 static inline bool rt_is_output_route(const struct rtable *rt) 77 { 78 return rt->rt_is_input == 0; 79 } 80 81 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr) 82 { 83 if (rt->rt_gateway) 84 return rt->rt_gateway; 85 return daddr; 86 } 87 88 struct ip_rt_acct { 89 __u32 o_bytes; 90 __u32 o_packets; 91 __u32 i_bytes; 92 __u32 i_packets; 93 }; 94 95 struct rt_cache_stat { 96 unsigned int in_slow_tot; 97 unsigned int in_slow_mc; 98 unsigned int in_no_route; 99 unsigned int in_brd; 100 unsigned int in_martian_dst; 101 unsigned int in_martian_src; 102 unsigned int out_slow_tot; 103 unsigned int out_slow_mc; 104 }; 105 106 extern struct ip_rt_acct __percpu *ip_rt_acct; 107 108 struct in_device; 109 110 int ip_rt_init(void); 111 void rt_cache_flush(struct net *net); 112 void rt_flush_dev(struct net_device *dev); 113 struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp); 114 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 115 struct sock *sk); 116 struct dst_entry *ipv4_blackhole_route(struct net *net, 117 struct dst_entry *dst_orig); 118 119 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp) 120 { 121 return ip_route_output_flow(net, flp, NULL); 122 } 123 124 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr, 125 __be32 saddr, u8 tos, int oif) 126 { 127 struct flowi4 fl4 = { 128 .flowi4_oif = oif, 129 .flowi4_tos = tos, 130 .daddr = daddr, 131 .saddr = saddr, 132 }; 133 return ip_route_output_key(net, &fl4); 134 } 135 136 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4, 137 struct sock *sk, 138 __be32 daddr, __be32 saddr, 139 __be16 dport, __be16 sport, 140 __u8 proto, __u8 tos, int oif) 141 { 142 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos, 143 RT_SCOPE_UNIVERSE, proto, 144 sk ? inet_sk_flowi_flags(sk) : 0, 145 daddr, saddr, dport, sport); 146 if (sk) 147 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 148 return ip_route_output_flow(net, fl4, sk); 149 } 150 151 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4, 152 __be32 daddr, __be32 saddr, 153 __be32 gre_key, __u8 tos, int oif) 154 { 155 memset(fl4, 0, sizeof(*fl4)); 156 fl4->flowi4_oif = oif; 157 fl4->daddr = daddr; 158 fl4->saddr = saddr; 159 fl4->flowi4_tos = tos; 160 fl4->flowi4_proto = IPPROTO_GRE; 161 fl4->fl4_gre_key = gre_key; 162 return ip_route_output_key(net, fl4); 163 } 164 165 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 166 u8 tos, struct net_device *devin); 167 168 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, 169 u8 tos, struct net_device *devin) 170 { 171 int err; 172 173 rcu_read_lock(); 174 err = ip_route_input_noref(skb, dst, src, tos, devin); 175 if (!err) 176 skb_dst_force(skb); 177 rcu_read_unlock(); 178 179 return err; 180 } 181 182 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 183 u32 mark, u8 protocol, int flow_flags); 184 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 185 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 186 u8 protocol, int flow_flags); 187 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 188 void ip_rt_send_redirect(struct sk_buff *skb); 189 190 unsigned int inet_addr_type(struct net *net, __be32 addr); 191 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id); 192 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 193 __be32 addr); 194 unsigned int inet_addr_type_dev_table(struct net *net, 195 const struct net_device *dev, 196 __be32 addr); 197 void ip_rt_multicast_event(struct in_device *); 198 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg); 199 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 200 201 struct in_ifaddr; 202 void fib_add_ifaddr(struct in_ifaddr *); 203 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 204 205 static inline void ip_rt_put(struct rtable *rt) 206 { 207 /* dst_release() accepts a NULL parameter. 208 * We rely on dst being first structure in struct rtable 209 */ 210 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 211 dst_release(&rt->dst); 212 } 213 214 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 215 216 extern const __u8 ip_tos2prio[16]; 217 218 static inline char rt_tos2priority(u8 tos) 219 { 220 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 221 } 222 223 /* ip_route_connect() and ip_route_newports() work in tandem whilst 224 * binding a socket for a new outgoing connection. 225 * 226 * In order to use IPSEC properly, we must, in the end, have a 227 * route that was looked up using all available keys including source 228 * and destination ports. 229 * 230 * However, if a source port needs to be allocated (the user specified 231 * a wildcard source port) we need to obtain addressing information 232 * in order to perform that allocation. 233 * 234 * So ip_route_connect() looks up a route using wildcarded source and 235 * destination ports in the key, simply so that we can get a pair of 236 * addresses to use for port allocation. 237 * 238 * Later, once the ports are allocated, ip_route_newports() will make 239 * another route lookup if needed to make sure we catch any IPSEC 240 * rules keyed on the port information. 241 * 242 * The callers allocate the flow key on their stack, and must pass in 243 * the same flowi4 object to both the ip_route_connect() and the 244 * ip_route_newports() calls. 245 */ 246 247 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 248 u32 tos, int oif, u8 protocol, 249 __be16 sport, __be16 dport, 250 struct sock *sk) 251 { 252 __u8 flow_flags = 0; 253 254 if (inet_sk(sk)->transparent) 255 flow_flags |= FLOWI_FLAG_ANYSRC; 256 257 if (netif_index_is_vrf(sock_net(sk), oif)) 258 flow_flags |= FLOWI_FLAG_VRFSRC; 259 260 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 261 protocol, flow_flags, dst, src, dport, sport); 262 } 263 264 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 265 __be32 dst, __be32 src, u32 tos, 266 int oif, u8 protocol, 267 __be16 sport, __be16 dport, 268 struct sock *sk) 269 { 270 struct net *net = sock_net(sk); 271 struct rtable *rt; 272 273 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 274 sport, dport, sk); 275 276 if (!dst || !src) { 277 rt = __ip_route_output_key(net, fl4); 278 if (IS_ERR(rt)) 279 return rt; 280 ip_rt_put(rt); 281 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 282 } 283 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 284 return ip_route_output_flow(net, fl4, sk); 285 } 286 287 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 288 __be16 orig_sport, __be16 orig_dport, 289 __be16 sport, __be16 dport, 290 struct sock *sk) 291 { 292 if (sport != orig_sport || dport != orig_dport) { 293 fl4->fl4_dport = dport; 294 fl4->fl4_sport = sport; 295 ip_rt_put(rt); 296 flowi4_update_output(fl4, sk->sk_bound_dev_if, 297 RT_CONN_FLAGS(sk), fl4->daddr, 298 fl4->saddr); 299 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 300 return ip_route_output_flow(sock_net(sk), fl4, sk); 301 } 302 return rt; 303 } 304 305 static inline int inet_iif(const struct sk_buff *skb) 306 { 307 int iif = skb_rtable(skb)->rt_iif; 308 309 if (iif) 310 return iif; 311 return skb->skb_iif; 312 } 313 314 extern int sysctl_ip_default_ttl; 315 316 static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 317 { 318 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 319 320 if (hoplimit == 0) 321 hoplimit = sysctl_ip_default_ttl; 322 return hoplimit; 323 } 324 325 #endif /* _ROUTE_H */ 326