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 <net/ip_fib.h>
32 #include <linux/in_route.h>
33 #include <linux/rtnetlink.h>
34 #include <linux/rcupdate.h>
35 #include <linux/route.h>
36 #include <linux/ip.h>
37 #include <linux/cache.h>
38 #include <linux/security.h>
39
40 /* IPv4 datagram length is stored into 16bit field (tot_len) */
41 #define IP_MAX_MTU 0xFFFFU
42
43 #define RTO_ONLINK 0x01
44
45 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
46 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
47
48 struct fib_nh;
49 struct fib_info;
50 struct uncached_list;
51 struct rtable {
52 struct dst_entry dst;
53
54 int rt_genid;
55 unsigned int rt_flags;
56 __u16 rt_type;
57 __u8 rt_is_input;
58 __u8 rt_uses_gateway;
59
60 int rt_iif;
61
62 /* Info on neighbour */
63 __be32 rt_gateway;
64
65 /* Miscellaneous cached information */
66 u32 rt_mtu_locked:1,
67 rt_pmtu:31;
68
69 u32 rt_table_id;
70
71 struct list_head rt_uncached;
72 struct uncached_list *rt_uncached_list;
73 };
74
rt_is_input_route(const struct rtable * rt)75 static inline bool rt_is_input_route(const struct rtable *rt)
76 {
77 return rt->rt_is_input != 0;
78 }
79
rt_is_output_route(const struct rtable * rt)80 static inline bool rt_is_output_route(const struct rtable *rt)
81 {
82 return rt->rt_is_input == 0;
83 }
84
rt_nexthop(const struct rtable * rt,__be32 daddr)85 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
86 {
87 if (rt->rt_gateway)
88 return rt->rt_gateway;
89 return daddr;
90 }
91
92 struct ip_rt_acct {
93 __u32 o_bytes;
94 __u32 o_packets;
95 __u32 i_bytes;
96 __u32 i_packets;
97 };
98
99 struct rt_cache_stat {
100 unsigned int in_slow_tot;
101 unsigned int in_slow_mc;
102 unsigned int in_no_route;
103 unsigned int in_brd;
104 unsigned int in_martian_dst;
105 unsigned int in_martian_src;
106 unsigned int out_slow_tot;
107 unsigned int out_slow_mc;
108 };
109
110 extern struct ip_rt_acct __percpu *ip_rt_acct;
111
112 struct in_device;
113
114 int ip_rt_init(void);
115 void rt_cache_flush(struct net *net);
116 void rt_flush_dev(struct net_device *dev);
117 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
118 const struct sk_buff *skb);
119 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
120 struct fib_result *res,
121 const struct sk_buff *skb);
122
__ip_route_output_key(struct net * net,struct flowi4 * flp)123 static inline struct rtable *__ip_route_output_key(struct net *net,
124 struct flowi4 *flp)
125 {
126 return ip_route_output_key_hash(net, flp, NULL);
127 }
128
129 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
130 const struct sock *sk);
131 struct dst_entry *ipv4_blackhole_route(struct net *net,
132 struct dst_entry *dst_orig);
133
ip_route_output_key(struct net * net,struct flowi4 * flp)134 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
135 {
136 return ip_route_output_flow(net, flp, NULL);
137 }
138
ip_route_output(struct net * net,__be32 daddr,__be32 saddr,u8 tos,int oif)139 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
140 __be32 saddr, u8 tos, int oif)
141 {
142 struct flowi4 fl4 = {
143 .flowi4_oif = oif,
144 .flowi4_tos = tos,
145 .daddr = daddr,
146 .saddr = saddr,
147 };
148 return ip_route_output_key(net, &fl4);
149 }
150
ip_route_output_ports(struct net * net,struct flowi4 * fl4,struct sock * sk,__be32 daddr,__be32 saddr,__be16 dport,__be16 sport,__u8 proto,__u8 tos,int oif)151 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
152 struct sock *sk,
153 __be32 daddr, __be32 saddr,
154 __be16 dport, __be16 sport,
155 __u8 proto, __u8 tos, int oif)
156 {
157 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
158 RT_SCOPE_UNIVERSE, proto,
159 sk ? inet_sk_flowi_flags(sk) : 0,
160 daddr, saddr, dport, sport, sock_net_uid(net, sk));
161 if (sk)
162 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
163 return ip_route_output_flow(net, fl4, sk);
164 }
165
ip_route_output_gre(struct net * net,struct flowi4 * fl4,__be32 daddr,__be32 saddr,__be32 gre_key,__u8 tos,int oif)166 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
167 __be32 daddr, __be32 saddr,
168 __be32 gre_key, __u8 tos, int oif)
169 {
170 memset(fl4, 0, sizeof(*fl4));
171 fl4->flowi4_oif = oif;
172 fl4->daddr = daddr;
173 fl4->saddr = saddr;
174 fl4->flowi4_tos = tos;
175 fl4->flowi4_proto = IPPROTO_GRE;
176 fl4->fl4_gre_key = gre_key;
177 return ip_route_output_key(net, fl4);
178 }
179 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
180 u8 tos, struct net_device *dev,
181 struct in_device *in_dev, u32 *itag);
182 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
183 u8 tos, struct net_device *devin);
184 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
185 u8 tos, struct net_device *devin,
186 struct fib_result *res);
187
ip_route_input(struct sk_buff * skb,__be32 dst,__be32 src,u8 tos,struct net_device * devin)188 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
189 u8 tos, struct net_device *devin)
190 {
191 int err;
192
193 rcu_read_lock();
194 err = ip_route_input_noref(skb, dst, src, tos, devin);
195 if (!err) {
196 skb_dst_force(skb);
197 if (!skb_dst(skb))
198 err = -EINVAL;
199 }
200 rcu_read_unlock();
201
202 return err;
203 }
204
205 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
206 u32 mark, u8 protocol, int flow_flags);
207 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
208 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
209 u8 protocol, int flow_flags);
210 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
211 void ip_rt_send_redirect(struct sk_buff *skb);
212
213 unsigned int inet_addr_type(struct net *net, __be32 addr);
214 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
215 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
216 __be32 addr);
217 unsigned int inet_addr_type_dev_table(struct net *net,
218 const struct net_device *dev,
219 __be32 addr);
220 void ip_rt_multicast_event(struct in_device *);
221 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
222 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
223 struct rtable *rt_dst_alloc(struct net_device *dev,
224 unsigned int flags, u16 type,
225 bool nopolicy, bool noxfrm, bool will_cache);
226
227 struct in_ifaddr;
228 void fib_add_ifaddr(struct in_ifaddr *);
229 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
230
ip_rt_put(struct rtable * rt)231 static inline void ip_rt_put(struct rtable *rt)
232 {
233 /* dst_release() accepts a NULL parameter.
234 * We rely on dst being first structure in struct rtable
235 */
236 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
237 dst_release(&rt->dst);
238 }
239
240 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
241
242 extern const __u8 ip_tos2prio[16];
243
rt_tos2priority(u8 tos)244 static inline char rt_tos2priority(u8 tos)
245 {
246 return ip_tos2prio[IPTOS_TOS(tos)>>1];
247 }
248
249 /* ip_route_connect() and ip_route_newports() work in tandem whilst
250 * binding a socket for a new outgoing connection.
251 *
252 * In order to use IPSEC properly, we must, in the end, have a
253 * route that was looked up using all available keys including source
254 * and destination ports.
255 *
256 * However, if a source port needs to be allocated (the user specified
257 * a wildcard source port) we need to obtain addressing information
258 * in order to perform that allocation.
259 *
260 * So ip_route_connect() looks up a route using wildcarded source and
261 * destination ports in the key, simply so that we can get a pair of
262 * addresses to use for port allocation.
263 *
264 * Later, once the ports are allocated, ip_route_newports() will make
265 * another route lookup if needed to make sure we catch any IPSEC
266 * rules keyed on the port information.
267 *
268 * The callers allocate the flow key on their stack, and must pass in
269 * the same flowi4 object to both the ip_route_connect() and the
270 * ip_route_newports() calls.
271 */
272
ip_route_connect_init(struct flowi4 * fl4,__be32 dst,__be32 src,u32 tos,int oif,u8 protocol,__be16 sport,__be16 dport,struct sock * sk)273 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
274 u32 tos, int oif, u8 protocol,
275 __be16 sport, __be16 dport,
276 struct sock *sk)
277 {
278 __u8 flow_flags = 0;
279
280 if (inet_sk(sk)->transparent)
281 flow_flags |= FLOWI_FLAG_ANYSRC;
282
283 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
284 protocol, flow_flags, dst, src, dport, sport,
285 sk->sk_uid);
286 }
287
ip_route_connect(struct flowi4 * fl4,__be32 dst,__be32 src,u32 tos,int oif,u8 protocol,__be16 sport,__be16 dport,struct sock * sk)288 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
289 __be32 dst, __be32 src, u32 tos,
290 int oif, u8 protocol,
291 __be16 sport, __be16 dport,
292 struct sock *sk)
293 {
294 struct net *net = sock_net(sk);
295 struct rtable *rt;
296
297 ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
298 sport, dport, sk);
299
300 if (!dst || !src) {
301 rt = __ip_route_output_key(net, fl4);
302 if (IS_ERR(rt))
303 return rt;
304 ip_rt_put(rt);
305 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
306 }
307 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
308 return ip_route_output_flow(net, fl4, sk);
309 }
310
ip_route_newports(struct flowi4 * fl4,struct rtable * rt,__be16 orig_sport,__be16 orig_dport,__be16 sport,__be16 dport,struct sock * sk)311 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
312 __be16 orig_sport, __be16 orig_dport,
313 __be16 sport, __be16 dport,
314 struct sock *sk)
315 {
316 if (sport != orig_sport || dport != orig_dport) {
317 fl4->fl4_dport = dport;
318 fl4->fl4_sport = sport;
319 ip_rt_put(rt);
320 flowi4_update_output(fl4, sk->sk_bound_dev_if,
321 RT_CONN_FLAGS(sk), fl4->daddr,
322 fl4->saddr);
323 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
324 return ip_route_output_flow(sock_net(sk), fl4, sk);
325 }
326 return rt;
327 }
328
inet_iif(const struct sk_buff * skb)329 static inline int inet_iif(const struct sk_buff *skb)
330 {
331 struct rtable *rt = skb_rtable(skb);
332
333 if (rt && rt->rt_iif)
334 return rt->rt_iif;
335
336 return skb->skb_iif;
337 }
338
ip4_dst_hoplimit(const struct dst_entry * dst)339 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
340 {
341 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
342 struct net *net = dev_net(dst->dev);
343
344 if (hoplimit == 0)
345 hoplimit = net->ipv4.sysctl_ip_default_ttl;
346 return hoplimit;
347 }
348
349 #endif /* _ROUTE_H */
350