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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 <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 extern int sysctl_ip_default_ttl;
333 
334 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
335 {
336         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
337 
338         if (hoplimit == 0)
339                 hoplimit = sysctl_ip_default_ttl;
340         return hoplimit;
341 }
342 
343 #endif  /* _ROUTE_H */
344 

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