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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 <net/l3mdev.h>
33 #include <linux/in_route.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/rcupdate.h>
36 #include <linux/route.h>
37 #include <linux/ip.h>
38 #include <linux/cache.h>
39 #include <linux/security.h>
40
41 /* IPv4 datagram length is stored into 16bit field (tot_len) */
42 #define IP_MAX_MTU 0xFFFFU
43
44 #define RTO_ONLINK 0x01
45
46 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
47 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
48
49 struct fib_nh;
50 struct fib_info;
51 struct uncached_list;
52 struct rtable {
53 struct dst_entry dst;
54
55 int rt_genid;
56 unsigned int rt_flags;
57 __u16 rt_type;
58 __u8 rt_is_input;
59 __u8 rt_uses_gateway;
60
61 int rt_iif;
62
63 /* Info on neighbour */
64 __be32 rt_gateway;
65
66 /* Miscellaneous cached information */
67 u32 rt_pmtu;
68
69 u32 rt_table_id;
70
71 struct list_head rt_uncached;
72 struct uncached_list *rt_uncached_list;
73 };
74
75 static inline bool rt_is_input_route(const struct rtable *rt)
76 {
77 return rt->rt_is_input != 0;
78 }
79
80 static inline bool rt_is_output_route(const struct rtable *rt)
81 {
82 return rt->rt_is_input == 0;
83 }
84
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 *, struct flowi4 *flp,
118 int mp_hash);
119
120 static inline struct rtable *__ip_route_output_key(struct net *net,
121 struct flowi4 *flp)
122 {
123 return __ip_route_output_key_hash(net, flp, -1);
124 }
125
126 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
127 const struct sock *sk);
128 struct dst_entry *ipv4_blackhole_route(struct net *net,
129 struct dst_entry *dst_orig);
130
131 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
132 {
133 return ip_route_output_flow(net, flp, NULL);
134 }
135
136 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
137 __be32 saddr, u8 tos, int oif)
138 {
139 struct flowi4 fl4 = {
140 .flowi4_oif = oif,
141 .flowi4_tos = tos,
142 .daddr = daddr,
143 .saddr = saddr,
144 };
145 return ip_route_output_key(net, &fl4);
146 }
147
148 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
149 struct sock *sk,
150 __be32 daddr, __be32 saddr,
151 __be16 dport, __be16 sport,
152 __u8 proto, __u8 tos, int oif)
153 {
154 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
155 RT_SCOPE_UNIVERSE, proto,
156 sk ? inet_sk_flowi_flags(sk) : 0,
157 daddr, saddr, dport, sport);
158 if (sk)
159 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
160 return ip_route_output_flow(net, fl4, sk);
161 }
162
163 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
164 __be32 daddr, __be32 saddr,
165 __be32 gre_key, __u8 tos, int oif)
166 {
167 memset(fl4, 0, sizeof(*fl4));
168 fl4->flowi4_oif = oif;
169 fl4->daddr = daddr;
170 fl4->saddr = saddr;
171 fl4->flowi4_tos = tos;
172 fl4->flowi4_proto = IPPROTO_GRE;
173 fl4->fl4_gre_key = gre_key;
174 return ip_route_output_key(net, fl4);
175 }
176
177 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
178 u8 tos, struct net_device *devin);
179
180 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
181 u8 tos, struct net_device *devin)
182 {
183 int err;
184
185 rcu_read_lock();
186 err = ip_route_input_noref(skb, dst, src, tos, devin);
187 if (!err)
188 skb_dst_force(skb);
189 rcu_read_unlock();
190
191 return err;
192 }
193
194 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
195 u32 mark, u8 protocol, int flow_flags);
196 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
197 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
198 u8 protocol, int flow_flags);
199 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
200 void ip_rt_send_redirect(struct sk_buff *skb);
201
202 unsigned int inet_addr_type(struct net *net, __be32 addr);
203 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
204 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
205 __be32 addr);
206 unsigned int inet_addr_type_dev_table(struct net *net,
207 const struct net_device *dev,
208 __be32 addr);
209 void ip_rt_multicast_event(struct in_device *);
210 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
211 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
212
213 struct in_ifaddr;
214 void fib_add_ifaddr(struct in_ifaddr *);
215 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
216
217 static inline void ip_rt_put(struct rtable *rt)
218 {
219 /* dst_release() accepts a NULL parameter.
220 * We rely on dst being first structure in struct rtable
221 */
222 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
223 dst_release(&rt->dst);
224 }
225
226 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
227
228 extern const __u8 ip_tos2prio[16];
229
230 static inline char rt_tos2priority(u8 tos)
231 {
232 return ip_tos2prio[IPTOS_TOS(tos)>>1];
233 }
234
235 /* ip_route_connect() and ip_route_newports() work in tandem whilst
236 * binding a socket for a new outgoing connection.
237 *
238 * In order to use IPSEC properly, we must, in the end, have a
239 * route that was looked up using all available keys including source
240 * and destination ports.
241 *
242 * However, if a source port needs to be allocated (the user specified
243 * a wildcard source port) we need to obtain addressing information
244 * in order to perform that allocation.
245 *
246 * So ip_route_connect() looks up a route using wildcarded source and
247 * destination ports in the key, simply so that we can get a pair of
248 * addresses to use for port allocation.
249 *
250 * Later, once the ports are allocated, ip_route_newports() will make
251 * another route lookup if needed to make sure we catch any IPSEC
252 * rules keyed on the port information.
253 *
254 * The callers allocate the flow key on their stack, and must pass in
255 * the same flowi4 object to both the ip_route_connect() and the
256 * ip_route_newports() calls.
257 */
258
259 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
260 u32 tos, int oif, u8 protocol,
261 __be16 sport, __be16 dport,
262 struct sock *sk)
263 {
264 __u8 flow_flags = 0;
265
266 if (inet_sk(sk)->transparent)
267 flow_flags |= FLOWI_FLAG_ANYSRC;
268
269 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
270 protocol, flow_flags, dst, src, dport, sport);
271 }
272
273 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
274 __be32 dst, __be32 src, u32 tos,
275 int oif, u8 protocol,
276 __be16 sport, __be16 dport,
277 struct sock *sk)
278 {
279 struct net *net = sock_net(sk);
280 struct rtable *rt;
281
282 ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
283 sport, dport, sk);
284
285 if (!src && oif) {
286 int rc;
287
288 rc = l3mdev_get_saddr(net, oif, fl4);
289 if (rc < 0)
290 return ERR_PTR(rc);
291
292 src = fl4->saddr;
293 }
294 if (!dst || !src) {
295 rt = __ip_route_output_key(net, fl4);
296 if (IS_ERR(rt))
297 return rt;
298 ip_rt_put(rt);
299 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
300 }
301 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
302 return ip_route_output_flow(net, fl4, sk);
303 }
304
305 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
306 __be16 orig_sport, __be16 orig_dport,
307 __be16 sport, __be16 dport,
308 struct sock *sk)
309 {
310 if (sport != orig_sport || dport != orig_dport) {
311 fl4->fl4_dport = dport;
312 fl4->fl4_sport = sport;
313 ip_rt_put(rt);
314 flowi4_update_output(fl4, sk->sk_bound_dev_if,
315 RT_CONN_FLAGS(sk), fl4->daddr,
316 fl4->saddr);
317 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
318 return ip_route_output_flow(sock_net(sk), fl4, sk);
319 }
320 return rt;
321 }
322
323 static inline int inet_iif(const struct sk_buff *skb)
324 {
325 int iif = skb_rtable(skb)->rt_iif;
326
327 if (iif)
328 return iif;
329 return skb->skb_iif;
330 }
331
332 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
333 {
334 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
335 struct net *net = dev_net(dst->dev);
336
337 if (hoplimit == 0)
338 hoplimit = net->ipv4.sysctl_ip_default_ttl;
339 return hoplimit;
340 }
341
342 #endif /* _ROUTE_H */