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 <net/inet_dscp.h>
31 #include <net/sock.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
ip_sock_rt_scope(const struct sock * sk)40 static inline __u8 ip_sock_rt_scope(const struct sock *sk)
41 {
42 if (sock_flag(sk, SOCK_LOCALROUTE))
43 return RT_SCOPE_LINK;
44
45 return RT_SCOPE_UNIVERSE;
46 }
47
ip_sock_rt_tos(const struct sock * sk)48 static inline __u8 ip_sock_rt_tos(const struct sock *sk)
49 {
50 return READ_ONCE(inet_sk(sk)->tos) & INET_DSCP_MASK;
51 }
52
53 struct ip_tunnel_info;
54 struct fib_nh;
55 struct fib_info;
56 struct uncached_list;
57 struct rtable {
58 struct dst_entry dst;
59
60 int rt_genid;
61 unsigned int rt_flags;
62 __u16 rt_type;
63 __u8 rt_is_input;
64 __u8 rt_uses_gateway;
65
66 int rt_iif;
67
68 u8 rt_gw_family;
69 /* Info on neighbour */
70 union {
71 __be32 rt_gw4;
72 struct in6_addr rt_gw6;
73 };
74
75 /* Miscellaneous cached information */
76 u32 rt_mtu_locked:1,
77 rt_pmtu:31;
78 };
79
80 #define dst_rtable(_ptr) container_of_const(_ptr, struct rtable, dst)
81
82 /**
83 * skb_rtable - Returns the skb &rtable
84 * @skb: buffer
85 */
skb_rtable(const struct sk_buff * skb)86 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
87 {
88 return dst_rtable(skb_dst(skb));
89 }
90
rt_is_input_route(const struct rtable * rt)91 static inline bool rt_is_input_route(const struct rtable *rt)
92 {
93 return rt->rt_is_input != 0;
94 }
95
rt_is_output_route(const struct rtable * rt)96 static inline bool rt_is_output_route(const struct rtable *rt)
97 {
98 return rt->rt_is_input == 0;
99 }
100
rt_nexthop(const struct rtable * rt,__be32 daddr)101 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
102 {
103 if (rt->rt_gw_family == AF_INET)
104 return rt->rt_gw4;
105 return daddr;
106 }
107
108 struct ip_rt_acct {
109 __u32 o_bytes;
110 __u32 o_packets;
111 __u32 i_bytes;
112 __u32 i_packets;
113 };
114
115 struct rt_cache_stat {
116 unsigned int in_slow_tot;
117 unsigned int in_slow_mc;
118 unsigned int in_no_route;
119 unsigned int in_brd;
120 unsigned int in_martian_dst;
121 unsigned int in_martian_src;
122 unsigned int out_slow_tot;
123 unsigned int out_slow_mc;
124 };
125
126 extern struct ip_rt_acct __percpu *ip_rt_acct;
127
128 struct in_device;
129
130 int ip_rt_init(void);
131 void rt_cache_flush(struct net *net);
132 void rt_flush_dev(struct net_device *dev);
133
inet_sk_init_flowi4(const struct inet_sock * inet,struct flowi4 * fl4)134 static inline void inet_sk_init_flowi4(const struct inet_sock *inet,
135 struct flowi4 *fl4)
136 {
137 const struct ip_options_rcu *ip4_opt;
138 const struct sock *sk;
139 __be32 daddr;
140
141 rcu_read_lock();
142 ip4_opt = rcu_dereference(inet->inet_opt);
143
144 /* Source routing option overrides the socket destination address */
145 if (ip4_opt && ip4_opt->opt.srr)
146 daddr = ip4_opt->opt.faddr;
147 else
148 daddr = inet->inet_daddr;
149 rcu_read_unlock();
150
151 sk = &inet->sk;
152 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
153 ip_sock_rt_tos(sk), ip_sock_rt_scope(sk),
154 sk->sk_protocol, inet_sk_flowi_flags(sk), daddr,
155 inet->inet_saddr, inet->inet_dport,
156 inet->inet_sport, sk->sk_uid);
157 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
158 }
159
160 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
161 const struct sk_buff *skb);
162 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
163 struct fib_result *res,
164 const struct sk_buff *skb);
165
__ip_route_output_key(struct net * net,struct flowi4 * flp)166 static inline struct rtable *__ip_route_output_key(struct net *net,
167 struct flowi4 *flp)
168 {
169 return ip_route_output_key_hash(net, flp, NULL);
170 }
171
172 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
173 const struct sock *sk);
174 struct dst_entry *ipv4_blackhole_route(struct net *net,
175 struct dst_entry *dst_orig);
176
ip_route_output_key(struct net * net,struct flowi4 * flp)177 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
178 {
179 return ip_route_output_flow(net, flp, NULL);
180 }
181
182 /* Simplistic IPv4 route lookup function.
183 * This is only suitable for some particular use cases: since the flowi4
184 * structure is only partially set, it may bypass some fib-rules.
185 */
ip_route_output(struct net * net,__be32 daddr,__be32 saddr,dscp_t dscp,int oif,__u8 scope)186 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
187 __be32 saddr, dscp_t dscp,
188 int oif, __u8 scope)
189 {
190 struct flowi4 fl4 = {
191 .flowi4_oif = oif,
192 .flowi4_tos = inet_dscp_to_dsfield(dscp),
193 .flowi4_scope = scope,
194 .daddr = daddr,
195 .saddr = saddr,
196 };
197
198 return ip_route_output_key(net, &fl4);
199 }
200
ip_route_output_ports(struct net * net,struct flowi4 * fl4,const struct sock * sk,__be32 daddr,__be32 saddr,__be16 dport,__be16 sport,__u8 proto,__u8 tos,int oif)201 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
202 const struct sock *sk,
203 __be32 daddr, __be32 saddr,
204 __be16 dport, __be16 sport,
205 __u8 proto, __u8 tos, int oif)
206 {
207 flowi4_init_output(fl4, oif, sk ? READ_ONCE(sk->sk_mark) : 0, tos,
208 sk ? ip_sock_rt_scope(sk) : RT_SCOPE_UNIVERSE,
209 proto, sk ? inet_sk_flowi_flags(sk) : 0,
210 daddr, saddr, dport, sport, sock_net_uid(net, sk));
211 if (sk)
212 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
213 return ip_route_output_flow(net, fl4, sk);
214 }
215
216 enum skb_drop_reason
217 ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
218 dscp_t dscp, struct net_device *dev,
219 struct in_device *in_dev, u32 *itag);
220 enum skb_drop_reason
221 ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
222 dscp_t dscp, struct net_device *dev);
223 enum skb_drop_reason
224 ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
225 dscp_t dscp, struct net_device *dev,
226 const struct sk_buff *hint);
227
228 static inline enum skb_drop_reason
ip_route_input(struct sk_buff * skb,__be32 dst,__be32 src,dscp_t dscp,struct net_device * devin)229 ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, dscp_t dscp,
230 struct net_device *devin)
231 {
232 enum skb_drop_reason reason;
233
234 rcu_read_lock();
235 reason = ip_route_input_noref(skb, dst, src, dscp, devin);
236 if (!reason) {
237 skb_dst_force(skb);
238 if (!skb_dst(skb))
239 reason = SKB_DROP_REASON_NOT_SPECIFIED;
240 }
241 rcu_read_unlock();
242
243 return reason;
244 }
245
246 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
247 u8 protocol);
248 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
249 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
250 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
251 void ip_rt_send_redirect(struct sk_buff *skb);
252
253 unsigned int inet_addr_type(struct net *net, __be32 addr);
254 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
255 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
256 __be32 addr);
257 unsigned int inet_addr_type_dev_table(struct net *net,
258 const struct net_device *dev,
259 __be32 addr);
260 void ip_rt_multicast_event(struct in_device *);
261 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
262 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
263 struct rtable *rt_dst_alloc(struct net_device *dev,
264 unsigned int flags, u16 type, bool noxfrm);
265 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
266
267 struct in_ifaddr;
268 void fib_add_ifaddr(struct in_ifaddr *);
269 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
270 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
271
272 void rt_add_uncached_list(struct rtable *rt);
273 void rt_del_uncached_list(struct rtable *rt);
274
275 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
276 u32 table_id, struct fib_info *fi,
277 int *fa_index, int fa_start, unsigned int flags);
278
ip_rt_put(struct rtable * rt)279 static inline void ip_rt_put(struct rtable *rt)
280 {
281 /* dst_release() accepts a NULL parameter.
282 * We rely on dst being first structure in struct rtable
283 */
284 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
285 dst_release(&rt->dst);
286 }
287
288 extern const __u8 ip_tos2prio[16];
289
rt_tos2priority(u8 tos)290 static inline char rt_tos2priority(u8 tos)
291 {
292 return ip_tos2prio[IPTOS_TOS(tos)>>1];
293 }
294
295 /* ip_route_connect() and ip_route_newports() work in tandem whilst
296 * binding a socket for a new outgoing connection.
297 *
298 * In order to use IPSEC properly, we must, in the end, have a
299 * route that was looked up using all available keys including source
300 * and destination ports.
301 *
302 * However, if a source port needs to be allocated (the user specified
303 * a wildcard source port) we need to obtain addressing information
304 * in order to perform that allocation.
305 *
306 * So ip_route_connect() looks up a route using wildcarded source and
307 * destination ports in the key, simply so that we can get a pair of
308 * addresses to use for port allocation.
309 *
310 * Later, once the ports are allocated, ip_route_newports() will make
311 * another route lookup if needed to make sure we catch any IPSEC
312 * rules keyed on the port information.
313 *
314 * The callers allocate the flow key on their stack, and must pass in
315 * the same flowi4 object to both the ip_route_connect() and the
316 * ip_route_newports() calls.
317 */
318
ip_route_connect_init(struct flowi4 * fl4,__be32 dst,__be32 src,int oif,u8 protocol,__be16 sport,__be16 dport,const struct sock * sk)319 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
320 __be32 src, int oif, u8 protocol,
321 __be16 sport, __be16 dport,
322 const struct sock *sk)
323 {
324 __u8 flow_flags = 0;
325
326 if (inet_test_bit(TRANSPARENT, sk))
327 flow_flags |= FLOWI_FLAG_ANYSRC;
328
329 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk),
330 ip_sock_rt_scope(sk), protocol, flow_flags, dst,
331 src, dport, sport, sk->sk_uid);
332 }
333
ip_route_connect(struct flowi4 * fl4,__be32 dst,__be32 src,int oif,u8 protocol,__be16 sport,__be16 dport,const struct sock * sk)334 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
335 __be32 src, int oif, u8 protocol,
336 __be16 sport, __be16 dport,
337 const struct sock *sk)
338 {
339 struct net *net = sock_net(sk);
340 struct rtable *rt;
341
342 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
343
344 if (!dst || !src) {
345 rt = __ip_route_output_key(net, fl4);
346 if (IS_ERR(rt))
347 return rt;
348 ip_rt_put(rt);
349 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr);
350 }
351 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
352 return ip_route_output_flow(net, fl4, sk);
353 }
354
ip_route_newports(struct flowi4 * fl4,struct rtable * rt,__be16 orig_sport,__be16 orig_dport,__be16 sport,__be16 dport,const struct sock * sk)355 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
356 __be16 orig_sport, __be16 orig_dport,
357 __be16 sport, __be16 dport,
358 const struct sock *sk)
359 {
360 if (sport != orig_sport || dport != orig_dport) {
361 fl4->fl4_dport = dport;
362 fl4->fl4_sport = sport;
363 ip_rt_put(rt);
364 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr,
365 fl4->saddr);
366 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
367 return ip_route_output_flow(sock_net(sk), fl4, sk);
368 }
369 return rt;
370 }
371
inet_iif(const struct sk_buff * skb)372 static inline int inet_iif(const struct sk_buff *skb)
373 {
374 struct rtable *rt = skb_rtable(skb);
375
376 if (rt && rt->rt_iif)
377 return rt->rt_iif;
378
379 return skb->skb_iif;
380 }
381
ip4_dst_hoplimit(const struct dst_entry * dst)382 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
383 {
384 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
385
386 if (hoplimit == 0) {
387 const struct net *net;
388
389 rcu_read_lock();
390 net = dev_net_rcu(dst->dev);
391 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
392 rcu_read_unlock();
393 }
394 return hoplimit;
395 }
396
ip_neigh_gw4(struct net_device * dev,__be32 daddr)397 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
398 __be32 daddr)
399 {
400 struct neighbour *neigh;
401
402 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
403 if (unlikely(!neigh))
404 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
405
406 return neigh;
407 }
408
ip_neigh_for_gw(struct rtable * rt,struct sk_buff * skb,bool * is_v6gw)409 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
410 struct sk_buff *skb,
411 bool *is_v6gw)
412 {
413 struct net_device *dev = rt->dst.dev;
414 struct neighbour *neigh;
415
416 if (likely(rt->rt_gw_family == AF_INET)) {
417 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
418 } else if (rt->rt_gw_family == AF_INET6) {
419 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
420 *is_v6gw = true;
421 } else {
422 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
423 }
424 return neigh;
425 }
426
427 #endif /* _ROUTE_H */
428