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 47struct fib_nh; 48struct fib_info; 49struct uncached_list; 50struct 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 71static inline bool rt_is_input_route(const struct rtable *rt) 72{ 73 return rt->rt_is_input != 0; 74} 75 76static inline bool rt_is_output_route(const struct rtable *rt) 77{ 78 return rt->rt_is_input == 0; 79} 80 81static 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 88struct ip_rt_acct { 89 __u32 o_bytes; 90 __u32 o_packets; 91 __u32 i_bytes; 92 __u32 i_packets; 93}; 94 95struct 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 106extern struct ip_rt_acct __percpu *ip_rt_acct; 107 108struct in_device; 109 110int ip_rt_init(void); 111void rt_cache_flush(struct net *net); 112void rt_flush_dev(struct net_device *dev); 113struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp); 114struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp, 115 struct sock *sk); 116struct dst_entry *ipv4_blackhole_route(struct net *net, 117 struct dst_entry *dst_orig); 118 119static 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 124static 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 136static 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 151static 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 165int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src, 166 u8 tos, struct net_device *devin); 167 168static 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 182void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif, 183 u32 mark, u8 protocol, int flow_flags); 184void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu); 185void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark, 186 u8 protocol, int flow_flags); 187void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk); 188void ip_rt_send_redirect(struct sk_buff *skb); 189 190unsigned int inet_addr_type(struct net *net, __be32 addr); 191unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev, 192 __be32 addr); 193void ip_rt_multicast_event(struct in_device *); 194int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg); 195void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt); 196 197struct in_ifaddr; 198void fib_add_ifaddr(struct in_ifaddr *); 199void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *); 200 201static inline void ip_rt_put(struct rtable *rt) 202{ 203 /* dst_release() accepts a NULL parameter. 204 * We rely on dst being first structure in struct rtable 205 */ 206 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0); 207 dst_release(&rt->dst); 208} 209 210#define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3) 211 212extern const __u8 ip_tos2prio[16]; 213 214static inline char rt_tos2priority(u8 tos) 215{ 216 return ip_tos2prio[IPTOS_TOS(tos)>>1]; 217} 218 219/* ip_route_connect() and ip_route_newports() work in tandem whilst 220 * binding a socket for a new outgoing connection. 221 * 222 * In order to use IPSEC properly, we must, in the end, have a 223 * route that was looked up using all available keys including source 224 * and destination ports. 225 * 226 * However, if a source port needs to be allocated (the user specified 227 * a wildcard source port) we need to obtain addressing information 228 * in order to perform that allocation. 229 * 230 * So ip_route_connect() looks up a route using wildcarded source and 231 * destination ports in the key, simply so that we can get a pair of 232 * addresses to use for port allocation. 233 * 234 * Later, once the ports are allocated, ip_route_newports() will make 235 * another route lookup if needed to make sure we catch any IPSEC 236 * rules keyed on the port information. 237 * 238 * The callers allocate the flow key on their stack, and must pass in 239 * the same flowi4 object to both the ip_route_connect() and the 240 * ip_route_newports() calls. 241 */ 242 243static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src, 244 u32 tos, int oif, u8 protocol, 245 __be16 sport, __be16 dport, 246 struct sock *sk) 247{ 248 __u8 flow_flags = 0; 249 250 if (inet_sk(sk)->transparent) 251 flow_flags |= FLOWI_FLAG_ANYSRC; 252 253 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE, 254 protocol, flow_flags, dst, src, dport, sport); 255} 256 257static inline struct rtable *ip_route_connect(struct flowi4 *fl4, 258 __be32 dst, __be32 src, u32 tos, 259 int oif, u8 protocol, 260 __be16 sport, __be16 dport, 261 struct sock *sk) 262{ 263 struct net *net = sock_net(sk); 264 struct rtable *rt; 265 266 ip_route_connect_init(fl4, dst, src, tos, oif, protocol, 267 sport, dport, sk); 268 269 if (!dst || !src) { 270 rt = __ip_route_output_key(net, fl4); 271 if (IS_ERR(rt)) 272 return rt; 273 ip_rt_put(rt); 274 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); 275 } 276 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 277 return ip_route_output_flow(net, fl4, sk); 278} 279 280static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt, 281 __be16 orig_sport, __be16 orig_dport, 282 __be16 sport, __be16 dport, 283 struct sock *sk) 284{ 285 if (sport != orig_sport || dport != orig_dport) { 286 fl4->fl4_dport = dport; 287 fl4->fl4_sport = sport; 288 ip_rt_put(rt); 289 flowi4_update_output(fl4, sk->sk_bound_dev_if, 290 RT_CONN_FLAGS(sk), fl4->daddr, 291 fl4->saddr); 292 security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); 293 return ip_route_output_flow(sock_net(sk), fl4, sk); 294 } 295 return rt; 296} 297 298static inline int inet_iif(const struct sk_buff *skb) 299{ 300 int iif = skb_rtable(skb)->rt_iif; 301 302 if (iif) 303 return iif; 304 return skb->skb_iif; 305} 306 307extern int sysctl_ip_default_ttl; 308 309static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 310{ 311 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); 312 313 if (hoplimit == 0) 314 hoplimit = sysctl_ip_default_ttl; 315 return hoplimit; 316} 317 318#endif /* _ROUTE_H */ 319