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

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