1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
7 * Definitions for the IP router.
9 * Version: @(#)route.h 1.0.4 05/27/93
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
14 * Alan Cox : Reformatted. Added ip_rt_local()
15 * Alan Cox : Support for TCP parameters.
16 * Alexey Kuznetsov: Major changes for new routing code.
17 * Mike McLagan : Routing by source
18 * Robert Olsson : Added rt_cache statistics
24 #include <net/inetpeer.h>
26 #include <net/inet_sock.h>
27 #include <net/ip_fib.h>
29 #include <net/ndisc.h>
30 #include <linux/in_route.h>
31 #include <linux/rtnetlink.h>
32 #include <linux/rcupdate.h>
33 #include <linux/route.h>
35 #include <linux/cache.h>
36 #include <linux/security.h>
38 /* IPv4 datagram length is stored into 16bit field (tot_len) */
39 #define IP_MAX_MTU 0xFFFFU
41 #define RTO_ONLINK 0x01
43 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
44 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
46 static inline __u8 ip_sock_rt_scope(const struct sock *sk)
48 if (sock_flag(sk, SOCK_LOCALROUTE))
51 return RT_SCOPE_UNIVERSE;
54 static inline __u8 ip_sock_rt_tos(const struct sock *sk)
56 return RT_TOS(inet_sk(sk)->tos);
59 struct ip_tunnel_info;
67 unsigned int rt_flags;
75 /* Info on neighbour */
78 struct in6_addr rt_gw6;
81 /* Miscellaneous cached information */
85 struct list_head rt_uncached;
86 struct uncached_list *rt_uncached_list;
89 static inline bool rt_is_input_route(const struct rtable *rt)
91 return rt->rt_is_input != 0;
94 static inline bool rt_is_output_route(const struct rtable *rt)
96 return rt->rt_is_input == 0;
99 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
101 if (rt->rt_gw_family == AF_INET)
113 struct rt_cache_stat {
114 unsigned int in_slow_tot;
115 unsigned int in_slow_mc;
116 unsigned int in_no_route;
118 unsigned int in_martian_dst;
119 unsigned int in_martian_src;
120 unsigned int out_slow_tot;
121 unsigned int out_slow_mc;
124 extern struct ip_rt_acct __percpu *ip_rt_acct;
128 int ip_rt_init(void);
129 void rt_cache_flush(struct net *net);
130 void rt_flush_dev(struct net_device *dev);
131 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
132 const struct sk_buff *skb);
133 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
134 struct fib_result *res,
135 const struct sk_buff *skb);
137 static inline struct rtable *__ip_route_output_key(struct net *net,
140 return ip_route_output_key_hash(net, flp, NULL);
143 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
144 const struct sock *sk);
145 struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
146 struct net_device *dev,
147 struct net *net, __be32 *saddr,
148 const struct ip_tunnel_info *info,
149 u8 protocol, bool use_cache);
151 struct dst_entry *ipv4_blackhole_route(struct net *net,
152 struct dst_entry *dst_orig);
154 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
156 return ip_route_output_flow(net, flp, NULL);
159 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
160 __be32 saddr, u8 tos, int oif)
162 struct flowi4 fl4 = {
168 return ip_route_output_key(net, &fl4);
171 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
173 __be32 daddr, __be32 saddr,
174 __be16 dport, __be16 sport,
175 __u8 proto, __u8 tos, int oif)
177 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
178 RT_SCOPE_UNIVERSE, proto,
179 sk ? inet_sk_flowi_flags(sk) : 0,
180 daddr, saddr, dport, sport, sock_net_uid(net, sk));
182 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
183 return ip_route_output_flow(net, fl4, sk);
186 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
187 __be32 daddr, __be32 saddr,
188 __be32 gre_key, __u8 tos, int oif)
190 memset(fl4, 0, sizeof(*fl4));
191 fl4->flowi4_oif = oif;
194 fl4->flowi4_tos = tos;
195 fl4->flowi4_proto = IPPROTO_GRE;
196 fl4->fl4_gre_key = gre_key;
197 return ip_route_output_key(net, fl4);
199 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
200 u8 tos, struct net_device *dev,
201 struct in_device *in_dev, u32 *itag);
202 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
203 u8 tos, struct net_device *devin);
204 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
205 u8 tos, struct net_device *devin,
206 const struct sk_buff *hint);
208 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
209 u8 tos, struct net_device *devin)
214 err = ip_route_input_noref(skb, dst, src, tos, devin);
225 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
227 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
228 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
229 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
230 void ip_rt_send_redirect(struct sk_buff *skb);
232 unsigned int inet_addr_type(struct net *net, __be32 addr);
233 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
234 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
236 unsigned int inet_addr_type_dev_table(struct net *net,
237 const struct net_device *dev,
239 void ip_rt_multicast_event(struct in_device *);
240 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
241 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
242 struct rtable *rt_dst_alloc(struct net_device *dev,
243 unsigned int flags, u16 type, bool noxfrm);
244 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
247 void fib_add_ifaddr(struct in_ifaddr *);
248 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
249 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
251 void rt_add_uncached_list(struct rtable *rt);
252 void rt_del_uncached_list(struct rtable *rt);
254 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
255 u32 table_id, struct fib_info *fi,
256 int *fa_index, int fa_start, unsigned int flags);
258 static inline void ip_rt_put(struct rtable *rt)
260 /* dst_release() accepts a NULL parameter.
261 * We rely on dst being first structure in struct rtable
263 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
264 dst_release(&rt->dst);
267 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
269 extern const __u8 ip_tos2prio[16];
271 static inline char rt_tos2priority(u8 tos)
273 return ip_tos2prio[IPTOS_TOS(tos)>>1];
276 /* ip_route_connect() and ip_route_newports() work in tandem whilst
277 * binding a socket for a new outgoing connection.
279 * In order to use IPSEC properly, we must, in the end, have a
280 * route that was looked up using all available keys including source
281 * and destination ports.
283 * However, if a source port needs to be allocated (the user specified
284 * a wildcard source port) we need to obtain addressing information
285 * in order to perform that allocation.
287 * So ip_route_connect() looks up a route using wildcarded source and
288 * destination ports in the key, simply so that we can get a pair of
289 * addresses to use for port allocation.
291 * Later, once the ports are allocated, ip_route_newports() will make
292 * another route lookup if needed to make sure we catch any IPSEC
293 * rules keyed on the port information.
295 * The callers allocate the flow key on their stack, and must pass in
296 * the same flowi4 object to both the ip_route_connect() and the
297 * ip_route_newports() calls.
300 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
301 __be32 src, int oif, u8 protocol,
302 __be16 sport, __be16 dport,
303 const struct sock *sk)
307 if (inet_sk(sk)->transparent)
308 flow_flags |= FLOWI_FLAG_ANYSRC;
310 flowi4_init_output(fl4, oif, sk->sk_mark, ip_sock_rt_tos(sk),
311 ip_sock_rt_scope(sk), protocol, flow_flags, dst,
312 src, dport, sport, sk->sk_uid);
315 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
316 __be32 src, int oif, u8 protocol,
317 __be16 sport, __be16 dport,
320 struct net *net = sock_net(sk);
323 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
326 rt = __ip_route_output_key(net, fl4);
330 flowi4_update_output(fl4, oif, fl4->flowi4_tos, fl4->daddr,
333 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
334 return ip_route_output_flow(net, fl4, sk);
337 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
338 __be16 orig_sport, __be16 orig_dport,
339 __be16 sport, __be16 dport,
342 if (sport != orig_sport || dport != orig_dport) {
343 fl4->fl4_dport = dport;
344 fl4->fl4_sport = sport;
346 flowi4_update_output(fl4, sk->sk_bound_dev_if,
347 RT_CONN_FLAGS(sk), fl4->daddr,
349 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
350 return ip_route_output_flow(sock_net(sk), fl4, sk);
355 static inline int inet_iif(const struct sk_buff *skb)
357 struct rtable *rt = skb_rtable(skb);
359 if (rt && rt->rt_iif)
365 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
367 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
368 struct net *net = dev_net(dst->dev);
371 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
375 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
378 struct neighbour *neigh;
380 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
381 if (unlikely(!neigh))
382 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
387 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
391 struct net_device *dev = rt->dst.dev;
392 struct neighbour *neigh;
394 if (likely(rt->rt_gw_family == AF_INET)) {
395 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
396 } else if (rt->rt_gw_family == AF_INET6) {
397 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
400 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
405 #endif /* _ROUTE_H */