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 static inline __u8 ip_sock_rt_scope(const struct sock *sk)
39 {
40 if (sock_flag(sk, SOCK_LOCALROUTE))
41 return RT_SCOPE_LINK;
42
43 return RT_SCOPE_UNIVERSE;
44 }
45
46 static inline __u8 ip_sock_rt_tos(const struct sock *sk)
47 {
48 return RT_TOS(READ_ONCE(inet_sk(sk)->tos));
49 }
50
51 struct ip_tunnel_info;
52 struct fib_nh;
53 struct fib_info;
54 struct uncached_list;
55 struct rtable {
56 struct dst_entry dst;
57
58 int rt_genid;
59 unsigned int rt_flags;
60 __u16 rt_type;
61 __u8 rt_is_input;
62 __u8 rt_uses_gateway;
63
64 int rt_iif;
65
66 u8 rt_gw_family;
67 /* Info on neighbour */
68 union {
69 __be32 rt_gw4;
70 struct in6_addr rt_gw6;
71 };
72
73 /* Miscellaneous cached information */
74 u32 rt_mtu_locked:1,
75 rt_pmtu:31;
76 };
77
78 #define dst_rtable(_ptr) container_of_const(_ptr, struct rtable, dst)
79
80 /**
81 * skb_rtable - Returns the skb &rtable
82 * @skb: buffer
83 */
84 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
85 {
86 return dst_rtable(skb_dst(skb));
87 }
88
89 static inline bool rt_is_input_route(const struct rtable *rt)
90 {
91 return rt->rt_is_input != 0;
92 }
93
94 static inline bool rt_is_output_route(const struct rtable *rt)
95 {
96 return rt->rt_is_input == 0;
97 }
98
99 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
100 {
101 if (rt->rt_gw_family == AF_INET)
102 return rt->rt_gw4;
103 return daddr;
104 }
105
106 struct ip_rt_acct {
107 __u32 o_bytes;
108 __u32 o_packets;
109 __u32 i_bytes;
110 __u32 i_packets;
111 };
112
113 struct rt_cache_stat {
114 unsigned int in_slow_tot;
115 unsigned int in_slow_mc;
116 unsigned int in_no_route;
117 unsigned int in_brd;
118 unsigned int in_martian_dst;
119 unsigned int in_martian_src;
120 unsigned int out_slow_tot;
121 unsigned int out_slow_mc;
122 };
123
124 extern struct ip_rt_acct __percpu *ip_rt_acct;
125
126 struct in_device;
127
128 int ip_rt_init(void);
129 void rt_cache_flush(struct net *net);
130 void rt_flush_dev(struct net_device *dev);
131 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
132 const struct sk_buff *skb);
133 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
134 struct fib_result *res,
135 const struct sk_buff *skb);
136
137 static inline struct rtable *__ip_route_output_key(struct net *net,
138 struct flowi4 *flp)
139 {
140 return ip_route_output_key_hash(net, flp, NULL);
141 }
142
143 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
144 const struct sock *sk);
145 struct dst_entry *ipv4_blackhole_route(struct net *net,
146 struct dst_entry *dst_orig);
147
148 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
149 {
150 return ip_route_output_flow(net, flp, NULL);
151 }
152
153 /* Simplistic IPv4 route lookup function.
154 * This is only suitable for some particular use cases: since the flowi4
155 * structure is only partially set, it may bypass some fib-rules.
156 */
157 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
158 __be32 saddr, u8 tos, int oif,
159 __u8 scope)
160 {
161 struct flowi4 fl4 = {
162 .flowi4_oif = oif,
163 .flowi4_tos = tos,
164 .flowi4_scope = scope,
165 .daddr = daddr,
166 .saddr = saddr,
167 };
168
169 return ip_route_output_key(net, &fl4);
170 }
171
172 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
173 const struct sock *sk,
174 __be32 daddr, __be32 saddr,
175 __be16 dport, __be16 sport,
176 __u8 proto, __u8 tos, int oif)
177 {
178 flowi4_init_output(fl4, oif, sk ? READ_ONCE(sk->sk_mark) : 0, tos,
179 sk ? ip_sock_rt_scope(sk) : RT_SCOPE_UNIVERSE,
180 proto, sk ? inet_sk_flowi_flags(sk) : 0,
181 daddr, saddr, dport, sport, sock_net_uid(net, sk));
182 if (sk)
183 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
184 return ip_route_output_flow(net, fl4, sk);
185 }
186
187 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
188 __be32 daddr, __be32 saddr,
189 __be32 gre_key, __u8 tos, int oif)
190 {
191 memset(fl4, 0, sizeof(*fl4));
192 fl4->flowi4_oif = oif;
193 fl4->daddr = daddr;
194 fl4->saddr = saddr;
195 fl4->flowi4_tos = tos;
196 fl4->flowi4_proto = IPPROTO_GRE;
197 fl4->fl4_gre_key = gre_key;
198 return ip_route_output_key(net, fl4);
199 }
200 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
201 u8 tos, struct net_device *dev,
202 struct in_device *in_dev, u32 *itag);
203 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
204 u8 tos, struct net_device *devin);
205 int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
206 u8 tos, struct net_device *devin,
207 const struct sk_buff *hint);
208
209 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
210 u8 tos, struct net_device *devin)
211 {
212 int err;
213
214 rcu_read_lock();
215 err = ip_route_input_noref(skb, dst, src, tos, devin);
216 if (!err) {
217 skb_dst_force(skb);
218 if (!skb_dst(skb))
219 err = -EINVAL;
220 }
221 rcu_read_unlock();
222
223 return err;
224 }
225
226 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
227 u8 protocol);
228 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
229 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
230 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
231 void ip_rt_send_redirect(struct sk_buff *skb);
232
233 unsigned int inet_addr_type(struct net *net, __be32 addr);
234 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
235 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
236 __be32 addr);
237 unsigned int inet_addr_type_dev_table(struct net *net,
238 const struct net_device *dev,
239 __be32 addr);
240 void ip_rt_multicast_event(struct in_device *);
241 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
242 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
243 struct rtable *rt_dst_alloc(struct net_device *dev,
244 unsigned int flags, u16 type, bool noxfrm);
245 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
246
247 struct in_ifaddr;
248 void fib_add_ifaddr(struct in_ifaddr *);
249 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
250 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
251
252 void rt_add_uncached_list(struct rtable *rt);
253 void rt_del_uncached_list(struct rtable *rt);
254
255 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
256 u32 table_id, struct fib_info *fi,
257 int *fa_index, int fa_start, unsigned int flags);
258
259 static inline void ip_rt_put(struct rtable *rt)
260 {
261 /* dst_release() accepts a NULL parameter.
262 * We rely on dst being first structure in struct rtable
263 */
264 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
265 dst_release(&rt->dst);
266 }
267
268 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
269
270 extern const __u8 ip_tos2prio[16];
271
272 static inline char rt_tos2priority(u8 tos)
273 {
274 return ip_tos2prio[IPTOS_TOS(tos)>>1];
275 }
276
277 /* ip_route_connect() and ip_route_newports() work in tandem whilst
278 * binding a socket for a new outgoing connection.
279 *
280 * In order to use IPSEC properly, we must, in the end, have a
281 * route that was looked up using all available keys including source
282 * and destination ports.
283 *
284 * However, if a source port needs to be allocated (the user specified
285 * a wildcard source port) we need to obtain addressing information
286 * in order to perform that allocation.
287 *
288 * So ip_route_connect() looks up a route using wildcarded source and
289 * destination ports in the key, simply so that we can get a pair of
290 * addresses to use for port allocation.
291 *
292 * Later, once the ports are allocated, ip_route_newports() will make
293 * another route lookup if needed to make sure we catch any IPSEC
294 * rules keyed on the port information.
295 *
296 * The callers allocate the flow key on their stack, and must pass in
297 * the same flowi4 object to both the ip_route_connect() and the
298 * ip_route_newports() calls.
299 */
300
301 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
302 __be32 src, int oif, u8 protocol,
303 __be16 sport, __be16 dport,
304 const struct sock *sk)
305 {
306 __u8 flow_flags = 0;
307
308 if (inet_test_bit(TRANSPARENT, sk))
309 flow_flags |= FLOWI_FLAG_ANYSRC;
310
311 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk),
312 ip_sock_rt_scope(sk), protocol, flow_flags, dst,
313 src, dport, sport, sk->sk_uid);
314 }
315
316 static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
317 __be32 src, int oif, u8 protocol,
318 __be16 sport, __be16 dport,
319 const struct sock *sk)
320 {
321 struct net *net = sock_net(sk);
322 struct rtable *rt;
323
324 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
325
326 if (!dst || !src) {
327 rt = __ip_route_output_key(net, fl4);
328 if (IS_ERR(rt))
329 return rt;
330 ip_rt_put(rt);
331 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr);
332 }
333 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
334 return ip_route_output_flow(net, fl4, sk);
335 }
336
337 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
338 __be16 orig_sport, __be16 orig_dport,
339 __be16 sport, __be16 dport,
340 const struct sock *sk)
341 {
342 if (sport != orig_sport || dport != orig_dport) {
343 fl4->fl4_dport = dport;
344 fl4->fl4_sport = sport;
345 ip_rt_put(rt);
346 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr,
347 fl4->saddr);
348 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
349 return ip_route_output_flow(sock_net(sk), fl4, sk);
350 }
351 return rt;
352 }
353
354 static inline int inet_iif(const struct sk_buff *skb)
355 {
356 struct rtable *rt = skb_rtable(skb);
357
358 if (rt && rt->rt_iif)
359 return rt->rt_iif;
360
361 return skb->skb_iif;
362 }
363
364 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
365 {
366 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
367 struct net *net = dev_net(dst->dev);
368
369 if (hoplimit == 0)
370 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
371 return hoplimit;
372 }
373
374 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
375 __be32 daddr)
376 {
377 struct neighbour *neigh;
378
379 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
380 if (unlikely(!neigh))
381 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
382
383 return neigh;
384 }
385
386 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
387 struct sk_buff *skb,
388 bool *is_v6gw)
389 {
390 struct net_device *dev = rt->dst.dev;
391 struct neighbour *neigh;
392
393 if (likely(rt->rt_gw_family == AF_INET)) {
394 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
395 } else if (rt->rt_gw_family == AF_INET6) {
396 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
397 *is_v6gw = true;
398 } else {
399 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
400 }
401 return neigh;
402 }
403
404 #endif /* _ROUTE_H */
405
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.