xref: /openbmc/linux/include/net/route.h (revision f7018c21)
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 rtable {
50 	struct dst_entry	dst;
51 
52 	int			rt_genid;
53 	unsigned int		rt_flags;
54 	__u16			rt_type;
55 	__u8			rt_is_input;
56 	__u8			rt_uses_gateway;
57 
58 	int			rt_iif;
59 
60 	/* Info on neighbour */
61 	__be32			rt_gateway;
62 
63 	/* Miscellaneous cached information */
64 	u32			rt_pmtu;
65 
66 	struct list_head	rt_uncached;
67 };
68 
69 static inline bool rt_is_input_route(const struct rtable *rt)
70 {
71 	return rt->rt_is_input != 0;
72 }
73 
74 static inline bool rt_is_output_route(const struct rtable *rt)
75 {
76 	return rt->rt_is_input == 0;
77 }
78 
79 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
80 {
81 	if (rt->rt_gateway)
82 		return rt->rt_gateway;
83 	return daddr;
84 }
85 
86 struct ip_rt_acct {
87 	__u32 	o_bytes;
88 	__u32 	o_packets;
89 	__u32 	i_bytes;
90 	__u32 	i_packets;
91 };
92 
93 struct rt_cache_stat {
94         unsigned int in_slow_tot;
95         unsigned int in_slow_mc;
96         unsigned int in_no_route;
97         unsigned int in_brd;
98         unsigned int in_martian_dst;
99         unsigned int in_martian_src;
100         unsigned int out_slow_tot;
101         unsigned int out_slow_mc;
102 };
103 
104 extern struct ip_rt_acct __percpu *ip_rt_acct;
105 
106 struct in_device;
107 
108 int ip_rt_init(void);
109 void rt_cache_flush(struct net *net);
110 void rt_flush_dev(struct net_device *dev);
111 struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
112 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
113 				    struct sock *sk);
114 struct dst_entry *ipv4_blackhole_route(struct net *net,
115 				       struct dst_entry *dst_orig);
116 
117 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
118 {
119 	return ip_route_output_flow(net, flp, NULL);
120 }
121 
122 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
123 					     __be32 saddr, u8 tos, int oif)
124 {
125 	struct flowi4 fl4 = {
126 		.flowi4_oif = oif,
127 		.flowi4_tos = tos,
128 		.daddr = daddr,
129 		.saddr = saddr,
130 	};
131 	return ip_route_output_key(net, &fl4);
132 }
133 
134 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
135 						   struct sock *sk,
136 						   __be32 daddr, __be32 saddr,
137 						   __be16 dport, __be16 sport,
138 						   __u8 proto, __u8 tos, int oif)
139 {
140 	flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
141 			   RT_SCOPE_UNIVERSE, proto,
142 			   sk ? inet_sk_flowi_flags(sk) : 0,
143 			   daddr, saddr, dport, sport);
144 	if (sk)
145 		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
146 	return ip_route_output_flow(net, fl4, sk);
147 }
148 
149 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
150 						 __be32 daddr, __be32 saddr,
151 						 __be32 gre_key, __u8 tos, int oif)
152 {
153 	memset(fl4, 0, sizeof(*fl4));
154 	fl4->flowi4_oif = oif;
155 	fl4->daddr = daddr;
156 	fl4->saddr = saddr;
157 	fl4->flowi4_tos = tos;
158 	fl4->flowi4_proto = IPPROTO_GRE;
159 	fl4->fl4_gre_key = gre_key;
160 	return ip_route_output_key(net, fl4);
161 }
162 
163 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
164 			 u8 tos, struct net_device *devin);
165 
166 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
167 				 u8 tos, struct net_device *devin)
168 {
169 	int err;
170 
171 	rcu_read_lock();
172 	err = ip_route_input_noref(skb, dst, src, tos, devin);
173 	if (!err)
174 		skb_dst_force(skb);
175 	rcu_read_unlock();
176 
177 	return err;
178 }
179 
180 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
181 		      u32 mark, u8 protocol, int flow_flags);
182 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
183 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
184 		   u8 protocol, int flow_flags);
185 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
186 void ip_rt_send_redirect(struct sk_buff *skb);
187 
188 unsigned int inet_addr_type(struct net *net, __be32 addr);
189 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
190 				__be32 addr);
191 void ip_rt_multicast_event(struct in_device *);
192 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
193 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
194 
195 struct in_ifaddr;
196 void fib_add_ifaddr(struct in_ifaddr *);
197 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
198 
199 static inline void ip_rt_put(struct rtable *rt)
200 {
201 	/* dst_release() accepts a NULL parameter.
202 	 * We rely on dst being first structure in struct rtable
203 	 */
204 	BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
205 	dst_release(&rt->dst);
206 }
207 
208 #define IPTOS_RT_MASK	(IPTOS_TOS_MASK & ~3)
209 
210 extern const __u8 ip_tos2prio[16];
211 
212 static inline char rt_tos2priority(u8 tos)
213 {
214 	return ip_tos2prio[IPTOS_TOS(tos)>>1];
215 }
216 
217 /* ip_route_connect() and ip_route_newports() work in tandem whilst
218  * binding a socket for a new outgoing connection.
219  *
220  * In order to use IPSEC properly, we must, in the end, have a
221  * route that was looked up using all available keys including source
222  * and destination ports.
223  *
224  * However, if a source port needs to be allocated (the user specified
225  * a wildcard source port) we need to obtain addressing information
226  * in order to perform that allocation.
227  *
228  * So ip_route_connect() looks up a route using wildcarded source and
229  * destination ports in the key, simply so that we can get a pair of
230  * addresses to use for port allocation.
231  *
232  * Later, once the ports are allocated, ip_route_newports() will make
233  * another route lookup if needed to make sure we catch any IPSEC
234  * rules keyed on the port information.
235  *
236  * The callers allocate the flow key on their stack, and must pass in
237  * the same flowi4 object to both the ip_route_connect() and the
238  * ip_route_newports() calls.
239  */
240 
241 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
242 					 u32 tos, int oif, u8 protocol,
243 					 __be16 sport, __be16 dport,
244 					 struct sock *sk)
245 {
246 	__u8 flow_flags = 0;
247 
248 	if (inet_sk(sk)->transparent)
249 		flow_flags |= FLOWI_FLAG_ANYSRC;
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)
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);
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 #endif	/* _ROUTE_H */
317