1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the IP router.
8 *
9 * Version: @(#)route.h 1.0.4 05/27/93
10 *
11 * Authors: Ross Biro
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 * Fixes:
14 * Alan Cox : Reformatted. Added ip_rt_local()
15 * Alan Cox : Support for TCP parameters.
16 * Alexey Kuznetsov: Major changes for new routing code.
17 * Mike McLagan : Routing by source
18 * Robert Olsson : Added rt_cache statistics
19 */
20 #ifndef _ROUTE_H
21 #define _ROUTE_H
22
23 #include <net/dst.h>
24 #include <net/inetpeer.h>
25 #include <net/flow.h>
26 #include <net/inet_sock.h>
27 #include <net/ip_fib.h>
28 #include <net/arp.h>
29 #include <net/ndisc.h>
30 #include <linux/in_route.h>
31 #include <linux/rtnetlink.h>
32 #include <linux/rcupdate.h>
33 #include <linux/route.h>
34 #include <linux/ip.h>
35 #include <linux/cache.h>
36 #include <linux/security.h>
37
38 /* IPv4 datagram length is stored into 16bit field (tot_len) */
39 #define IP_MAX_MTU 0xFFFFU
40
41 #define RTO_ONLINK 0x01
42
43 #define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
44 #define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
45
46 struct fib_nh;
47 struct fib_info;
48 struct uncached_list;
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 u8 rt_gw_family;
61 /* Info on neighbour */
62 union {
63 __be32 rt_gw4;
64 struct in6_addr rt_gw6;
65 };
66
67 /* Miscellaneous cached information */
68 u32 rt_mtu_locked:1,
69 rt_pmtu:31;
70
71 struct list_head rt_uncached;
72 struct uncached_list *rt_uncached_list;
73 };
74
rt_is_input_route(const struct rtable * rt)75 static inline bool rt_is_input_route(const struct rtable *rt)
76 {
77 return rt->rt_is_input != 0;
78 }
79
rt_is_output_route(const struct rtable * rt)80 static inline bool rt_is_output_route(const struct rtable *rt)
81 {
82 return rt->rt_is_input == 0;
83 }
84
rt_nexthop(const struct rtable * rt,__be32 daddr)85 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
86 {
87 if (rt->rt_gw_family == AF_INET)
88 return rt->rt_gw4;
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 *net, struct flowi4 *flp,
118 const struct sk_buff *skb);
119 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
120 struct fib_result *res,
121 const struct sk_buff *skb);
122
__ip_route_output_key(struct net * net,struct flowi4 * flp)123 static inline struct rtable *__ip_route_output_key(struct net *net,
124 struct flowi4 *flp)
125 {
126 return ip_route_output_key_hash(net, flp, NULL);
127 }
128
129 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
130 const struct sock *sk);
131 struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
132 struct net_device *dev,
133 struct net *net, __be32 *saddr,
134 const struct ip_tunnel_info *info,
135 u8 protocol, bool use_cache);
136
137 struct dst_entry *ipv4_blackhole_route(struct net *net,
138 struct dst_entry *dst_orig);
139
ip_route_output_key(struct net * net,struct flowi4 * flp)140 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
141 {
142 return ip_route_output_flow(net, flp, NULL);
143 }
144
ip_route_output(struct net * net,__be32 daddr,__be32 saddr,u8 tos,int oif)145 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
146 __be32 saddr, u8 tos, int oif)
147 {
148 struct flowi4 fl4 = {
149 .flowi4_oif = oif,
150 .flowi4_tos = tos,
151 .daddr = daddr,
152 .saddr = saddr,
153 };
154 return ip_route_output_key(net, &fl4);
155 }
156
ip_route_output_ports(struct net * net,struct flowi4 * fl4,struct sock * sk,__be32 daddr,__be32 saddr,__be16 dport,__be16 sport,__u8 proto,__u8 tos,int oif)157 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
158 struct sock *sk,
159 __be32 daddr, __be32 saddr,
160 __be16 dport, __be16 sport,
161 __u8 proto, __u8 tos, int oif)
162 {
163 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
164 RT_SCOPE_UNIVERSE, proto,
165 sk ? inet_sk_flowi_flags(sk) : 0,
166 daddr, saddr, dport, sport, sock_net_uid(net, sk));
167 if (sk)
168 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
169 return ip_route_output_flow(net, fl4, sk);
170 }
171
ip_route_output_gre(struct net * net,struct flowi4 * fl4,__be32 daddr,__be32 saddr,__be32 gre_key,__u8 tos,int oif)172 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
173 __be32 daddr, __be32 saddr,
174 __be32 gre_key, __u8 tos, int oif)
175 {
176 memset(fl4, 0, sizeof(*fl4));
177 fl4->flowi4_oif = oif;
178 fl4->daddr = daddr;
179 fl4->saddr = saddr;
180 fl4->flowi4_tos = tos;
181 fl4->flowi4_proto = IPPROTO_GRE;
182 fl4->fl4_gre_key = gre_key;
183 return ip_route_output_key(net, fl4);
184 }
185 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
186 u8 tos, struct net_device *dev,
187 struct in_device *in_dev, u32 *itag);
188 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
189 u8 tos, struct net_device *devin);
190 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
191 u8 tos, struct net_device *devin,
192 struct fib_result *res);
193
194 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
195 u8 tos, struct net_device *devin,
196 const struct sk_buff *hint);
197
ip_route_input(struct sk_buff * skb,__be32 dst,__be32 src,u8 tos,struct net_device * devin)198 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
199 u8 tos, struct net_device *devin)
200 {
201 int err;
202
203 rcu_read_lock();
204 err = ip_route_input_noref(skb, dst, src, tos, devin);
205 if (!err) {
206 skb_dst_force(skb);
207 if (!skb_dst(skb))
208 err = -EINVAL;
209 }
210 rcu_read_unlock();
211
212 return err;
213 }
214
215 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
216 u8 protocol);
217 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
218 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
219 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
220 void ip_rt_send_redirect(struct sk_buff *skb);
221
222 unsigned int inet_addr_type(struct net *net, __be32 addr);
223 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
224 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
225 __be32 addr);
226 unsigned int inet_addr_type_dev_table(struct net *net,
227 const struct net_device *dev,
228 __be32 addr);
229 void ip_rt_multicast_event(struct in_device *);
230 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
231 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
232 struct rtable *rt_dst_alloc(struct net_device *dev,
233 unsigned int flags, u16 type,
234 bool nopolicy, bool noxfrm);
235 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
236
237 struct in_ifaddr;
238 void fib_add_ifaddr(struct in_ifaddr *);
239 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
240 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
241
242 void rt_add_uncached_list(struct rtable *rt);
243 void rt_del_uncached_list(struct rtable *rt);
244
245 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
246 u32 table_id, struct fib_info *fi,
247 int *fa_index, int fa_start, unsigned int flags);
248
ip_rt_put(struct rtable * rt)249 static inline void ip_rt_put(struct rtable *rt)
250 {
251 /* dst_release() accepts a NULL parameter.
252 * We rely on dst being first structure in struct rtable
253 */
254 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
255 dst_release(&rt->dst);
256 }
257
258 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
259
260 extern const __u8 ip_tos2prio[16];
261
rt_tos2priority(u8 tos)262 static inline char rt_tos2priority(u8 tos)
263 {
264 return ip_tos2prio[IPTOS_TOS(tos)>>1];
265 }
266
267 /* ip_route_connect() and ip_route_newports() work in tandem whilst
268 * binding a socket for a new outgoing connection.
269 *
270 * In order to use IPSEC properly, we must, in the end, have a
271 * route that was looked up using all available keys including source
272 * and destination ports.
273 *
274 * However, if a source port needs to be allocated (the user specified
275 * a wildcard source port) we need to obtain addressing information
276 * in order to perform that allocation.
277 *
278 * So ip_route_connect() looks up a route using wildcarded source and
279 * destination ports in the key, simply so that we can get a pair of
280 * addresses to use for port allocation.
281 *
282 * Later, once the ports are allocated, ip_route_newports() will make
283 * another route lookup if needed to make sure we catch any IPSEC
284 * rules keyed on the port information.
285 *
286 * The callers allocate the flow key on their stack, and must pass in
287 * the same flowi4 object to both the ip_route_connect() and the
288 * ip_route_newports() calls.
289 */
290
ip_route_connect_init(struct flowi4 * fl4,__be32 dst,__be32 src,u32 tos,int oif,u8 protocol,__be16 sport,__be16 dport,struct sock * sk)291 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
292 u32 tos, int oif, u8 protocol,
293 __be16 sport, __be16 dport,
294 struct sock *sk)
295 {
296 __u8 flow_flags = 0;
297
298 if (inet_sk(sk)->transparent)
299 flow_flags |= FLOWI_FLAG_ANYSRC;
300
301 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
302 protocol, flow_flags, dst, src, dport, sport,
303 sk->sk_uid);
304 }
305
ip_route_connect(struct flowi4 * fl4,__be32 dst,__be32 src,u32 tos,int oif,u8 protocol,__be16 sport,__be16 dport,struct sock * sk)306 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
307 __be32 dst, __be32 src, u32 tos,
308 int oif, u8 protocol,
309 __be16 sport, __be16 dport,
310 struct sock *sk)
311 {
312 struct net *net = sock_net(sk);
313 struct rtable *rt;
314
315 ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
316 sport, dport, sk);
317
318 if (!dst || !src) {
319 rt = __ip_route_output_key(net, fl4);
320 if (IS_ERR(rt))
321 return rt;
322 ip_rt_put(rt);
323 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
324 }
325 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
326 return ip_route_output_flow(net, fl4, sk);
327 }
328
ip_route_newports(struct flowi4 * fl4,struct rtable * rt,__be16 orig_sport,__be16 orig_dport,__be16 sport,__be16 dport,struct sock * sk)329 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
330 __be16 orig_sport, __be16 orig_dport,
331 __be16 sport, __be16 dport,
332 struct sock *sk)
333 {
334 if (sport != orig_sport || dport != orig_dport) {
335 fl4->fl4_dport = dport;
336 fl4->fl4_sport = sport;
337 ip_rt_put(rt);
338 flowi4_update_output(fl4, sk->sk_bound_dev_if,
339 RT_CONN_FLAGS(sk), fl4->daddr,
340 fl4->saddr);
341 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
342 return ip_route_output_flow(sock_net(sk), fl4, sk);
343 }
344 return rt;
345 }
346
inet_iif(const struct sk_buff * skb)347 static inline int inet_iif(const struct sk_buff *skb)
348 {
349 struct rtable *rt = skb_rtable(skb);
350
351 if (rt && rt->rt_iif)
352 return rt->rt_iif;
353
354 return skb->skb_iif;
355 }
356
ip4_dst_hoplimit(const struct dst_entry * dst)357 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
358 {
359 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
360 struct net *net = dev_net(dst->dev);
361
362 if (hoplimit == 0)
363 hoplimit = net->ipv4.sysctl_ip_default_ttl;
364 return hoplimit;
365 }
366
ip_neigh_gw4(struct net_device * dev,__be32 daddr)367 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
368 __be32 daddr)
369 {
370 struct neighbour *neigh;
371
372 neigh = __ipv4_neigh_lookup_noref(dev, daddr);
373 if (unlikely(!neigh))
374 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
375
376 return neigh;
377 }
378
ip_neigh_for_gw(struct rtable * rt,struct sk_buff * skb,bool * is_v6gw)379 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
380 struct sk_buff *skb,
381 bool *is_v6gw)
382 {
383 struct net_device *dev = rt->dst.dev;
384 struct neighbour *neigh;
385
386 if (likely(rt->rt_gw_family == AF_INET)) {
387 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
388 } else if (rt->rt_gw_family == AF_INET6) {
389 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
390 *is_v6gw = true;
391 } else {
392 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
393 }
394 return neigh;
395 }
396
397 #endif /* _ROUTE_H */
398
