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Linux/include/net/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 /* 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 

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