xref: /openbmc/linux/include/net/route.h (revision 12eb4683)
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 #define RTO_ONLINK	0x01
40 
41 #define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
42 #define RT_CONN_FLAGS_TOS(sk,tos)   (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
43 
44 struct fib_nh;
45 struct fib_info;
46 struct rtable {
47 	struct dst_entry	dst;
48 
49 	int			rt_genid;
50 	unsigned int		rt_flags;
51 	__u16			rt_type;
52 	__u8			rt_is_input;
53 	__u8			rt_uses_gateway;
54 
55 	int			rt_iif;
56 
57 	/* Info on neighbour */
58 	__be32			rt_gateway;
59 
60 	/* Miscellaneous cached information */
61 	u32			rt_pmtu;
62 
63 	struct list_head	rt_uncached;
64 };
65 
66 static inline bool rt_is_input_route(const struct rtable *rt)
67 {
68 	return rt->rt_is_input != 0;
69 }
70 
71 static inline bool rt_is_output_route(const struct rtable *rt)
72 {
73 	return rt->rt_is_input == 0;
74 }
75 
76 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
77 {
78 	if (rt->rt_gateway)
79 		return rt->rt_gateway;
80 	return daddr;
81 }
82 
83 struct ip_rt_acct {
84 	__u32 	o_bytes;
85 	__u32 	o_packets;
86 	__u32 	i_bytes;
87 	__u32 	i_packets;
88 };
89 
90 struct rt_cache_stat {
91         unsigned int in_slow_tot;
92         unsigned int in_slow_mc;
93         unsigned int in_no_route;
94         unsigned int in_brd;
95         unsigned int in_martian_dst;
96         unsigned int in_martian_src;
97         unsigned int out_slow_tot;
98         unsigned int out_slow_mc;
99 };
100 
101 extern struct ip_rt_acct __percpu *ip_rt_acct;
102 
103 struct in_device;
104 
105 int ip_rt_init(void);
106 void rt_cache_flush(struct net *net);
107 void rt_flush_dev(struct net_device *dev);
108 struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
109 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
110 				    struct sock *sk);
111 struct dst_entry *ipv4_blackhole_route(struct net *net,
112 				       struct dst_entry *dst_orig);
113 
114 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
115 {
116 	return ip_route_output_flow(net, flp, NULL);
117 }
118 
119 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
120 					     __be32 saddr, u8 tos, int oif)
121 {
122 	struct flowi4 fl4 = {
123 		.flowi4_oif = oif,
124 		.flowi4_tos = tos,
125 		.daddr = daddr,
126 		.saddr = saddr,
127 	};
128 	return ip_route_output_key(net, &fl4);
129 }
130 
131 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
132 						   struct sock *sk,
133 						   __be32 daddr, __be32 saddr,
134 						   __be16 dport, __be16 sport,
135 						   __u8 proto, __u8 tos, int oif)
136 {
137 	flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
138 			   RT_SCOPE_UNIVERSE, proto,
139 			   sk ? inet_sk_flowi_flags(sk) : 0,
140 			   daddr, saddr, dport, sport);
141 	if (sk)
142 		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
143 	return ip_route_output_flow(net, fl4, sk);
144 }
145 
146 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
147 						 __be32 daddr, __be32 saddr,
148 						 __be32 gre_key, __u8 tos, int oif)
149 {
150 	memset(fl4, 0, sizeof(*fl4));
151 	fl4->flowi4_oif = oif;
152 	fl4->daddr = daddr;
153 	fl4->saddr = saddr;
154 	fl4->flowi4_tos = tos;
155 	fl4->flowi4_proto = IPPROTO_GRE;
156 	fl4->fl4_gre_key = gre_key;
157 	return ip_route_output_key(net, fl4);
158 }
159 
160 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
161 			 u8 tos, struct net_device *devin);
162 
163 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
164 				 u8 tos, struct net_device *devin)
165 {
166 	int err;
167 
168 	rcu_read_lock();
169 	err = ip_route_input_noref(skb, dst, src, tos, devin);
170 	if (!err)
171 		skb_dst_force(skb);
172 	rcu_read_unlock();
173 
174 	return err;
175 }
176 
177 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
178 		      u32 mark, u8 protocol, int flow_flags);
179 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
180 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
181 		   u8 protocol, int flow_flags);
182 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
183 void ip_rt_send_redirect(struct sk_buff *skb);
184 
185 unsigned int inet_addr_type(struct net *net, __be32 addr);
186 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
187 				__be32 addr);
188 void ip_rt_multicast_event(struct in_device *);
189 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
190 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
191 int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb);
192 
193 struct in_ifaddr;
194 void fib_add_ifaddr(struct in_ifaddr *);
195 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
196 
197 static inline void ip_rt_put(struct rtable *rt)
198 {
199 	/* dst_release() accepts a NULL parameter.
200 	 * We rely on dst being first structure in struct rtable
201 	 */
202 	BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
203 	dst_release(&rt->dst);
204 }
205 
206 #define IPTOS_RT_MASK	(IPTOS_TOS_MASK & ~3)
207 
208 extern const __u8 ip_tos2prio[16];
209 
210 static inline char rt_tos2priority(u8 tos)
211 {
212 	return ip_tos2prio[IPTOS_TOS(tos)>>1];
213 }
214 
215 /* ip_route_connect() and ip_route_newports() work in tandem whilst
216  * binding a socket for a new outgoing connection.
217  *
218  * In order to use IPSEC properly, we must, in the end, have a
219  * route that was looked up using all available keys including source
220  * and destination ports.
221  *
222  * However, if a source port needs to be allocated (the user specified
223  * a wildcard source port) we need to obtain addressing information
224  * in order to perform that allocation.
225  *
226  * So ip_route_connect() looks up a route using wildcarded source and
227  * destination ports in the key, simply so that we can get a pair of
228  * addresses to use for port allocation.
229  *
230  * Later, once the ports are allocated, ip_route_newports() will make
231  * another route lookup if needed to make sure we catch any IPSEC
232  * rules keyed on the port information.
233  *
234  * The callers allocate the flow key on their stack, and must pass in
235  * the same flowi4 object to both the ip_route_connect() and the
236  * ip_route_newports() calls.
237  */
238 
239 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
240 					 u32 tos, int oif, u8 protocol,
241 					 __be16 sport, __be16 dport,
242 					 struct sock *sk, bool can_sleep)
243 {
244 	__u8 flow_flags = 0;
245 
246 	if (inet_sk(sk)->transparent)
247 		flow_flags |= FLOWI_FLAG_ANYSRC;
248 	if (can_sleep)
249 		flow_flags |= FLOWI_FLAG_CAN_SLEEP;
250 
251 	flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
252 			   protocol, flow_flags, dst, src, dport, sport);
253 }
254 
255 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
256 					      __be32 dst, __be32 src, u32 tos,
257 					      int oif, u8 protocol,
258 					      __be16 sport, __be16 dport,
259 					      struct sock *sk, bool can_sleep)
260 {
261 	struct net *net = sock_net(sk);
262 	struct rtable *rt;
263 
264 	ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
265 			      sport, dport, sk, can_sleep);
266 
267 	if (!dst || !src) {
268 		rt = __ip_route_output_key(net, fl4);
269 		if (IS_ERR(rt))
270 			return rt;
271 		ip_rt_put(rt);
272 		flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
273 	}
274 	security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
275 	return ip_route_output_flow(net, fl4, sk);
276 }
277 
278 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
279 					       __be16 orig_sport, __be16 orig_dport,
280 					       __be16 sport, __be16 dport,
281 					       struct sock *sk)
282 {
283 	if (sport != orig_sport || dport != orig_dport) {
284 		fl4->fl4_dport = dport;
285 		fl4->fl4_sport = sport;
286 		ip_rt_put(rt);
287 		flowi4_update_output(fl4, sk->sk_bound_dev_if,
288 				     RT_CONN_FLAGS(sk), fl4->daddr,
289 				     fl4->saddr);
290 		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
291 		return ip_route_output_flow(sock_net(sk), fl4, sk);
292 	}
293 	return rt;
294 }
295 
296 static inline int inet_iif(const struct sk_buff *skb)
297 {
298 	int iif = skb_rtable(skb)->rt_iif;
299 
300 	if (iif)
301 		return iif;
302 	return skb->skb_iif;
303 }
304 
305 extern int sysctl_ip_default_ttl;
306 
307 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
308 {
309 	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
310 
311 	if (hoplimit == 0)
312 		hoplimit = sysctl_ip_default_ttl;
313 	return hoplimit;
314 }
315 
316 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
317 {
318 	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE;
319 }
320 
321 static inline bool ip_sk_use_pmtu(const struct sock *sk)
322 {
323 	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
324 }
325 
326 static inline int ip_skb_dst_mtu(const struct sk_buff *skb)
327 {
328 	return (!skb->sk || ip_sk_use_pmtu(skb->sk)) ?
329 	       dst_mtu(skb_dst(skb)) : skb_dst(skb)->dev->mtu;
330 }
331 
332 #endif	/* _ROUTE_H */
333