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 dst_entry *ipv4_blackhole_route(struct net *net,
132 struct dst_entry *dst_orig);
133
ip_route_output_key(struct net * net,struct flowi4 * flp)134 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
135 {
136 return ip_route_output_flow(net, flp, NULL);
137 }
138
ip_route_output(struct net * net,__be32 daddr,__be32 saddr,u8 tos,int oif)139 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
140 __be32 saddr, u8 tos, int oif)
141 {
142 struct flowi4 fl4 = {
143 .flowi4_oif = oif,
144 .flowi4_tos = tos,
145 .daddr = daddr,
146 .saddr = saddr,
147 };
148 return ip_route_output_key(net, &fl4);
149 }
150
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)151 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
152 struct sock *sk,
153 __be32 daddr, __be32 saddr,
154 __be16 dport, __be16 sport,
155 __u8 proto, __u8 tos, int oif)
156 {
157 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
158 RT_SCOPE_UNIVERSE, proto,
159 sk ? inet_sk_flowi_flags(sk) : 0,
160 daddr, saddr, dport, sport, sock_net_uid(net, sk));
161 if (sk)
162 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
163 return ip_route_output_flow(net, fl4, sk);
164 }
165
ip_route_output_gre(struct net * net,struct flowi4 * fl4,__be32 daddr,__be32 saddr,__be32 gre_key,__u8 tos,int oif)166 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
167 __be32 daddr, __be32 saddr,
168 __be32 gre_key, __u8 tos, int oif)
169 {
170 memset(fl4, 0, sizeof(*fl4));
171 fl4->flowi4_oif = oif;
172 fl4->daddr = daddr;
173 fl4->saddr = saddr;
174 fl4->flowi4_tos = tos;
175 fl4->flowi4_proto = IPPROTO_GRE;
176 fl4->fl4_gre_key = gre_key;
177 return ip_route_output_key(net, fl4);
178 }
179 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
180 u8 tos, struct net_device *dev,
181 struct in_device *in_dev, u32 *itag);
182 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
183 u8 tos, struct net_device *devin);
184 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
185 u8 tos, struct net_device *devin,
186 struct fib_result *res);
187
ip_route_input(struct sk_buff * skb,__be32 dst,__be32 src,u8 tos,struct net_device * devin)188 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
189 u8 tos, struct net_device *devin)
190 {
191 int err;
192
193 rcu_read_lock();
194 err = ip_route_input_noref(skb, dst, src, tos, devin);
195 if (!err) {
196 skb_dst_force(skb);
197 if (!skb_dst(skb))
198 err = -EINVAL;
199 }
200 rcu_read_unlock();
201
202 return err;
203 }
204
205 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
206 u8 protocol);
207 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
208 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
209 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
210 void ip_rt_send_redirect(struct sk_buff *skb);
211
212 unsigned int inet_addr_type(struct net *net, __be32 addr);
213 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
214 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
215 __be32 addr);
216 unsigned int inet_addr_type_dev_table(struct net *net,
217 const struct net_device *dev,
218 __be32 addr);
219 void ip_rt_multicast_event(struct in_device *);
220 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
221 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
222 struct rtable *rt_dst_alloc(struct net_device *dev,
223 unsigned int flags, u16 type,
224 bool nopolicy, bool noxfrm, bool will_cache);
225 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
226
227 struct in_ifaddr;
228 void fib_add_ifaddr(struct in_ifaddr *);
229 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
230 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
231
232 void rt_add_uncached_list(struct rtable *rt);
233 void rt_del_uncached_list(struct rtable *rt);
234
235 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
236 u32 table_id, struct fib_info *fi,
237 int *fa_index, int fa_start, unsigned int flags);
238
ip_rt_put(struct rtable * rt)239 static inline void ip_rt_put(struct rtable *rt)
240 {
241 /* dst_release() accepts a NULL parameter.
242 * We rely on dst being first structure in struct rtable
243 */
244 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
245 dst_release(&rt->dst);
246 }
247
248 #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
249
250 extern const __u8 ip_tos2prio[16];
251
rt_tos2priority(u8 tos)252 static inline char rt_tos2priority(u8 tos)
253 {
254 return ip_tos2prio[IPTOS_TOS(tos)>>1];
255 }
256
257 /* ip_route_connect() and ip_route_newports() work in tandem whilst
258 * binding a socket for a new outgoing connection.
259 *
260 * In order to use IPSEC properly, we must, in the end, have a
261 * route that was looked up using all available keys including source
262 * and destination ports.
263 *
264 * However, if a source port needs to be allocated (the user specified
265 * a wildcard source port) we need to obtain addressing information
266 * in order to perform that allocation.
267 *
268 * So ip_route_connect() looks up a route using wildcarded source and
269 * destination ports in the key, simply so that we can get a pair of
270 * addresses to use for port allocation.
271 *
272 * Later, once the ports are allocated, ip_route_newports() will make
273 * another route lookup if needed to make sure we catch any IPSEC
274 * rules keyed on the port information.
275 *
276 * The callers allocate the flow key on their stack, and must pass in
277 * the same flowi4 object to both the ip_route_connect() and the
278 * ip_route_newports() calls.
279 */
280
ip_route_connect_init(struct flowi4 * fl4,__be32 dst,__be32 src,u32 tos,int oif,u8 protocol,__be16 sport,__be16 dport,struct sock * sk)281 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
282 u32 tos, int oif, u8 protocol,
283 __be16 sport, __be16 dport,
284 struct sock *sk)
285 {
286 __u8 flow_flags = 0;
287
288 if (inet_sk(sk)->transparent)
289 flow_flags |= FLOWI_FLAG_ANYSRC;
290
291 flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
292 protocol, flow_flags, dst, src, dport, sport,
293 sk->sk_uid);
294 }
295
ip_route_connect(struct flowi4 * fl4,__be32 dst,__be32 src,u32 tos,int oif,u8 protocol,__be16 sport,__be16 dport,struct sock * sk)296 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
297 __be32 dst, __be32 src, u32 tos,
298 int oif, u8 protocol,
299 __be16 sport, __be16 dport,
300 struct sock *sk)
301 {
302 struct net *net = sock_net(sk);
303 struct rtable *rt;
304
305 ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
306 sport, dport, sk);
307
308 if (!dst || !src) {
309 rt = __ip_route_output_key(net, fl4);
310 if (IS_ERR(rt))
311 return rt;
312 ip_rt_put(rt);
313 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
314 }
315 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
316 return ip_route_output_flow(net, fl4, sk);
317 }
318
ip_route_newports(struct flowi4 * fl4,struct rtable * rt,__be16 orig_sport,__be16 orig_dport,__be16 sport,__be16 dport,struct sock * sk)319 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
320 __be16 orig_sport, __be16 orig_dport,
321 __be16 sport, __be16 dport,
322 struct sock *sk)
323 {
324 if (sport != orig_sport || dport != orig_dport) {
325 fl4->fl4_dport = dport;
326 fl4->fl4_sport = sport;
327 ip_rt_put(rt);
328 flowi4_update_output(fl4, sk->sk_bound_dev_if,
329 RT_CONN_FLAGS(sk), fl4->daddr,
330 fl4->saddr);
331 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
332 return ip_route_output_flow(sock_net(sk), fl4, sk);
333 }
334 return rt;
335 }
336
inet_iif(const struct sk_buff * skb)337 static inline int inet_iif(const struct sk_buff *skb)
338 {
339 struct rtable *rt = skb_rtable(skb);
340
341 if (rt && rt->rt_iif)
342 return rt->rt_iif;
343
344 return skb->skb_iif;
345 }
346
ip4_dst_hoplimit(const struct dst_entry * dst)347 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
348 {
349 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
350 struct net *net = dev_net(dst->dev);
351
352 if (hoplimit == 0)
353 hoplimit = net->ipv4.sysctl_ip_default_ttl;
354 return hoplimit;
355 }
356
ip_neigh_gw4(struct net_device * dev,__be32 daddr)357 static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
358 __be32 daddr)
359 {
360 struct neighbour *neigh;
361
362 neigh = __ipv4_neigh_lookup_noref(dev, daddr);
363 if (unlikely(!neigh))
364 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
365
366 return neigh;
367 }
368
ip_neigh_for_gw(struct rtable * rt,struct sk_buff * skb,bool * is_v6gw)369 static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
370 struct sk_buff *skb,
371 bool *is_v6gw)
372 {
373 struct net_device *dev = rt->dst.dev;
374 struct neighbour *neigh;
375
376 if (likely(rt->rt_gw_family == AF_INET)) {
377 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
378 } else if (rt->rt_gw_family == AF_INET6) {
379 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
380 *is_v6gw = true;
381 } else {
382 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
383 }
384 return neigh;
385 }
386
387 #endif /* _ROUTE_H */
388
