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
46static inline __u8 ip_sock_rt_scope(const struct sock *sk)
47{
48 if (sock_flag(sk, SOCK_LOCALROUTE))
49 return RT_SCOPE_LINK;
50
51 return RT_SCOPE_UNIVERSE;
52}
53
54static inline __u8 ip_sock_rt_tos(const struct sock *sk)
55{
56 return RT_TOS(inet_sk(sk)->tos);
57}
58
59struct ip_tunnel_info;
60struct fib_nh;
61struct fib_info;
62struct uncached_list;
63struct rtable {
64 struct dst_entry dst;
65
66 int rt_genid;
67 unsigned int rt_flags;
68 __u16 rt_type;
69 __u8 rt_is_input;
70 __u8 rt_uses_gateway;
71
72 int rt_iif;
73
74 u8 rt_gw_family;
75 /* Info on neighbour */
76 union {
77 __be32 rt_gw4;
78 struct in6_addr rt_gw6;
79 };
80
81 /* Miscellaneous cached information */
82 u32 rt_mtu_locked:1,
83 rt_pmtu:31;
84
85 struct list_head rt_uncached;
86 struct uncached_list *rt_uncached_list;
87};
88
89static inline bool rt_is_input_route(const struct rtable *rt)
90{
91 return rt->rt_is_input != 0;
92}
93
94static inline bool rt_is_output_route(const struct rtable *rt)
95{
96 return rt->rt_is_input == 0;
97}
98
99static 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
106struct ip_rt_acct {
107 __u32 o_bytes;
108 __u32 o_packets;
109 __u32 i_bytes;
110 __u32 i_packets;
111};
112
113struct 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
124extern struct ip_rt_acct __percpu *ip_rt_acct;
125
126struct in_device;
127
128int ip_rt_init(void);
129void rt_cache_flush(struct net *net);
130void rt_flush_dev(struct net_device *dev);
131struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
132 const struct sk_buff *skb);
133struct 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
137static 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
143struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
144 const struct sock *sk);
145struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
146 struct net_device *dev,
147 struct net *net, __be32 *saddr,
148 const struct ip_tunnel_info *info,
149 u8 protocol, bool use_cache);
150
151struct dst_entry *ipv4_blackhole_route(struct net *net,
152 struct dst_entry *dst_orig);
153
154static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
155{
156 return ip_route_output_flow(net, flp, NULL);
157}
158
159static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
160 __be32 saddr, u8 tos, int oif)
161{
162 struct flowi4 fl4 = {
163 .flowi4_oif = oif,
164 .flowi4_tos = tos,
165 .daddr = daddr,
166 .saddr = saddr,
167 };
168 return ip_route_output_key(net, &fl4);
169}
170
171static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
172 struct sock *sk,
173 __be32 daddr, __be32 saddr,
174 __be16 dport, __be16 sport,
175 __u8 proto, __u8 tos, int oif)
176{
177 flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
178 RT_SCOPE_UNIVERSE, proto,
179 sk ? inet_sk_flowi_flags(sk) : 0,
180 daddr, saddr, dport, sport, sock_net_uid(net, sk));
181 if (sk)
182 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
183 return ip_route_output_flow(net, fl4, sk);
184}
185
186static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
187 __be32 daddr, __be32 saddr,
188 __be32 gre_key, __u8 tos, int oif)
189{
190 memset(fl4, 0, sizeof(*fl4));
191 fl4->flowi4_oif = oif;
192 fl4->daddr = daddr;
193 fl4->saddr = saddr;
194 fl4->flowi4_tos = tos;
195 fl4->flowi4_proto = IPPROTO_GRE;
196 fl4->fl4_gre_key = gre_key;
197 return ip_route_output_key(net, fl4);
198}
199int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
200 u8 tos, struct net_device *dev,
201 struct in_device *in_dev, u32 *itag);
202int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
203 u8 tos, struct net_device *devin);
204int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
205 u8 tos, struct net_device *devin,
206 const struct sk_buff *hint);
207
208static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
209 u8 tos, struct net_device *devin)
210{
211 int err;
212
213 rcu_read_lock();
214 err = ip_route_input_noref(skb, dst, src, tos, devin);
215 if (!err) {
216 skb_dst_force(skb);
217 if (!skb_dst(skb))
218 err = -EINVAL;
219 }
220 rcu_read_unlock();
221
222 return err;
223}
224
225void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
226 u8 protocol);
227void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
228void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
229void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
230void ip_rt_send_redirect(struct sk_buff *skb);
231
232unsigned int inet_addr_type(struct net *net, __be32 addr);
233unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
234unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
235 __be32 addr);
236unsigned int inet_addr_type_dev_table(struct net *net,
237 const struct net_device *dev,
238 __be32 addr);
239void ip_rt_multicast_event(struct in_device *);
240int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
241void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
242struct rtable *rt_dst_alloc(struct net_device *dev,
243 unsigned int flags, u16 type, bool noxfrm);
244struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
245
246struct in_ifaddr;
247void fib_add_ifaddr(struct in_ifaddr *);
248void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
249void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
250
251void rt_add_uncached_list(struct rtable *rt);
252void rt_del_uncached_list(struct rtable *rt);
253
254int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
255 u32 table_id, struct fib_info *fi,
256 int *fa_index, int fa_start, unsigned int flags);
257
258static inline void ip_rt_put(struct rtable *rt)
259{
260 /* dst_release() accepts a NULL parameter.
261 * We rely on dst being first structure in struct rtable
262 */
263 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
264 dst_release(&rt->dst);
265}
266
267#define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
268
269extern const __u8 ip_tos2prio[16];
270
271static inline char rt_tos2priority(u8 tos)
272{
273 return ip_tos2prio[IPTOS_TOS(tos)>>1];
274}
275
276/* ip_route_connect() and ip_route_newports() work in tandem whilst
277 * binding a socket for a new outgoing connection.
278 *
279 * In order to use IPSEC properly, we must, in the end, have a
280 * route that was looked up using all available keys including source
281 * and destination ports.
282 *
283 * However, if a source port needs to be allocated (the user specified
284 * a wildcard source port) we need to obtain addressing information
285 * in order to perform that allocation.
286 *
287 * So ip_route_connect() looks up a route using wildcarded source and
288 * destination ports in the key, simply so that we can get a pair of
289 * addresses to use for port allocation.
290 *
291 * Later, once the ports are allocated, ip_route_newports() will make
292 * another route lookup if needed to make sure we catch any IPSEC
293 * rules keyed on the port information.
294 *
295 * The callers allocate the flow key on their stack, and must pass in
296 * the same flowi4 object to both the ip_route_connect() and the
297 * ip_route_newports() calls.
298 */
299
300static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
301 __be32 src, int oif, u8 protocol,
302 __be16 sport, __be16 dport,
303 const struct sock *sk)
304{
305 __u8 flow_flags = 0;
306
307 if (inet_sk(sk)->transparent)
308 flow_flags |= FLOWI_FLAG_ANYSRC;
309
310 flowi4_init_output(fl4, oif, sk->sk_mark, ip_sock_rt_tos(sk),
311 ip_sock_rt_scope(sk), protocol, flow_flags, dst,
312 src, dport, sport, sk->sk_uid);
313}
314
315static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
316 __be32 src, int oif, u8 protocol,
317 __be16 sport, __be16 dport,
318 struct sock *sk)
319{
320 struct net *net = sock_net(sk);
321 struct rtable *rt;
322
323 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
324
325 if (!dst || !src) {
326 rt = __ip_route_output_key(net, fl4);
327 if (IS_ERR(rt))
328 return rt;
329 ip_rt_put(rt);
330 flowi4_update_output(fl4, oif, fl4->flowi4_tos, fl4->daddr,
331 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
337static 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 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,
347 RT_CONN_FLAGS(sk), fl4->daddr,
348 fl4->saddr);
349 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
350 return ip_route_output_flow(sock_net(sk), fl4, sk);
351 }
352 return rt;
353}
354
355static inline int inet_iif(const struct sk_buff *skb)
356{
357 struct rtable *rt = skb_rtable(skb);
358
359 if (rt && rt->rt_iif)
360 return rt->rt_iif;
361
362 return skb->skb_iif;
363}
364
365static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
366{
367 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
368 struct net *net = dev_net(dst->dev);
369
370 if (hoplimit == 0)
371 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
372 return hoplimit;
373}
374
375static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
376 __be32 daddr)
377{
378 struct neighbour *neigh;
379
380 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
381 if (unlikely(!neigh))
382 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
383
384 return neigh;
385}
386
387static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
388 struct sk_buff *skb,
389 bool *is_v6gw)
390{
391 struct net_device *dev = rt->dst.dev;
392 struct neighbour *neigh;
393
394 if (likely(rt->rt_gw_family == AF_INET)) {
395 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
396 } else if (rt->rt_gw_family == AF_INET6) {
397 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
398 *is_v6gw = true;
399 } else {
400 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
401 }
402 return neigh;
403}
404
405#endif /* _ROUTE_H */
406

source code of linux/include/net/route.h