route.h

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