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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 <linux/in_route.h>
32#include <linux/rtnetlink.h>
33#include <linux/rcupdate.h>
34#include <linux/route.h>
35#include <linux/ip.h>
36#include <linux/cache.h>
37#include <linux/security.h>
38
39static inline __u8 ip_sock_rt_scope(const struct sock *sk)
40{
41 if (sock_flag(sk, SOCK_LOCALROUTE))
42 return RT_SCOPE_LINK;
43
44 return RT_SCOPE_UNIVERSE;
45}
46
47static inline __u8 ip_sock_rt_tos(const struct sock *sk)
48{
49 return READ_ONCE(inet_sk(sk)->tos) & INET_DSCP_MASK;
50}
51
52struct ip_tunnel_info;
53struct fib_nh;
54struct fib_info;
55struct uncached_list;
56struct rtable {
57 struct dst_entry dst;
58
59 int rt_genid;
60 unsigned int rt_flags;
61 __u16 rt_type;
62 __u8 rt_is_input;
63 __u8 rt_uses_gateway;
64
65 int rt_iif;
66
67 u8 rt_gw_family;
68 /* Info on neighbour */
69 union {
70 __be32 rt_gw4;
71 struct in6_addr rt_gw6;
72 };
73
74 /* Miscellaneous cached information */
75 u32 rt_mtu_locked:1,
76 rt_pmtu:31;
77};
78
79#define dst_rtable(_ptr) container_of_const(_ptr, struct rtable, dst)
80
81/**
82 * skb_rtable - Returns the skb &rtable
83 * @skb: buffer
84 */
85static inline struct rtable *skb_rtable(const struct sk_buff *skb)
86{
87 return dst_rtable(skb_dst(skb));
88}
89
90static inline bool rt_is_input_route(const struct rtable *rt)
91{
92 return rt->rt_is_input != 0;
93}
94
95static inline bool rt_is_output_route(const struct rtable *rt)
96{
97 return rt->rt_is_input == 0;
98}
99
100static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
101{
102 if (rt->rt_gw_family == AF_INET)
103 return rt->rt_gw4;
104 return daddr;
105}
106
107struct ip_rt_acct {
108 __u32 o_bytes;
109 __u32 o_packets;
110 __u32 i_bytes;
111 __u32 i_packets;
112};
113
114struct rt_cache_stat {
115 unsigned int in_slow_tot;
116 unsigned int in_slow_mc;
117 unsigned int in_no_route;
118 unsigned int in_brd;
119 unsigned int in_martian_dst;
120 unsigned int in_martian_src;
121 unsigned int out_slow_tot;
122 unsigned int out_slow_mc;
123};
124
125extern struct ip_rt_acct __percpu *ip_rt_acct;
126
127struct in_device;
128
129int ip_rt_init(void);
130void rt_cache_flush(struct net *net);
131void rt_flush_dev(struct net_device *dev);
132struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
133 const struct sk_buff *skb);
134struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
135 struct fib_result *res,
136 const struct sk_buff *skb);
137
138static inline struct rtable *__ip_route_output_key(struct net *net,
139 struct flowi4 *flp)
140{
141 return ip_route_output_key_hash(net, flp, NULL);
142}
143
144struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
145 const struct sock *sk);
146struct dst_entry *ipv4_blackhole_route(struct net *net,
147 struct dst_entry *dst_orig);
148
149static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
150{
151 return ip_route_output_flow(net, flp, NULL);
152}
153
154/* Simplistic IPv4 route lookup function.
155 * This is only suitable for some particular use cases: since the flowi4
156 * structure is only partially set, it may bypass some fib-rules.
157 */
158static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
159 __be32 saddr, u8 tos, int oif,
160 __u8 scope)
161{
162 struct flowi4 fl4 = {
163 .flowi4_oif = oif,
164 .flowi4_tos = tos,
165 .flowi4_scope = scope,
166 .daddr = daddr,
167 .saddr = saddr,
168 };
169
170 return ip_route_output_key(net, &fl4);
171}
172
173static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
174 const struct sock *sk,
175 __be32 daddr, __be32 saddr,
176 __be16 dport, __be16 sport,
177 __u8 proto, __u8 tos, int oif)
178{
179 flowi4_init_output(fl4, oif, sk ? READ_ONCE(sk->sk_mark) : 0, tos,
180 sk ? ip_sock_rt_scope(sk) : RT_SCOPE_UNIVERSE,
181 proto, sk ? inet_sk_flowi_flags(sk) : 0,
182 daddr, saddr, dport, sport, sock_net_uid(net, sk));
183 if (sk)
184 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
185 return ip_route_output_flow(net, fl4, sk);
186}
187
188static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
189 __be32 daddr, __be32 saddr,
190 __be32 gre_key, __u8 tos, int oif)
191{
192 memset(fl4, 0, sizeof(*fl4));
193 fl4->flowi4_oif = oif;
194 fl4->daddr = daddr;
195 fl4->saddr = saddr;
196 fl4->flowi4_tos = tos;
197 fl4->flowi4_proto = IPPROTO_GRE;
198 fl4->fl4_gre_key = gre_key;
199 return ip_route_output_key(net, fl4);
200}
201int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
202 u8 tos, struct net_device *dev,
203 struct in_device *in_dev, u32 *itag);
204int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
205 u8 tos, struct net_device *devin);
206int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
207 u8 tos, struct net_device *devin,
208 const struct sk_buff *hint);
209
210static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
211 u8 tos, struct net_device *devin)
212{
213 int err;
214
215 rcu_read_lock();
216 err = ip_route_input_noref(skb, dst, src, tos, devin);
217 if (!err) {
218 skb_dst_force(skb);
219 if (!skb_dst(skb))
220 err = -EINVAL;
221 }
222 rcu_read_unlock();
223
224 return err;
225}
226
227void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
228 u8 protocol);
229void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
230void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
231void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
232void ip_rt_send_redirect(struct sk_buff *skb);
233
234unsigned int inet_addr_type(struct net *net, __be32 addr);
235unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
236unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
237 __be32 addr);
238unsigned int inet_addr_type_dev_table(struct net *net,
239 const struct net_device *dev,
240 __be32 addr);
241void ip_rt_multicast_event(struct in_device *);
242int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
243void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
244struct rtable *rt_dst_alloc(struct net_device *dev,
245 unsigned int flags, u16 type, bool noxfrm);
246struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
247
248struct in_ifaddr;
249void fib_add_ifaddr(struct in_ifaddr *);
250void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
251void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
252
253void rt_add_uncached_list(struct rtable *rt);
254void rt_del_uncached_list(struct rtable *rt);
255
256int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
257 u32 table_id, struct fib_info *fi,
258 int *fa_index, int fa_start, unsigned int flags);
259
260static inline void ip_rt_put(struct rtable *rt)
261{
262 /* dst_release() accepts a NULL parameter.
263 * We rely on dst being first structure in struct rtable
264 */
265 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
266 dst_release(&rt->dst);
267}
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_test_bit(TRANSPARENT, sk))
308 flow_flags |= FLOWI_FLAG_ANYSRC;
309
310 flowi4_init_output(fl4, oif, READ_ONCE(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 const 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->daddr, fl4->saddr);
331 }
332 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
333 return ip_route_output_flow(net, fl4, sk);
334}
335
336static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
337 __be16 orig_sport, __be16 orig_dport,
338 __be16 sport, __be16 dport,
339 const struct sock *sk)
340{
341 if (sport != orig_sport || dport != orig_dport) {
342 fl4->fl4_dport = dport;
343 fl4->fl4_sport = sport;
344 ip_rt_put(rt);
345 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr,
346 fl4->saddr);
347 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
348 return ip_route_output_flow(sock_net(sk), fl4, sk);
349 }
350 return rt;
351}
352
353static inline int inet_iif(const struct sk_buff *skb)
354{
355 struct rtable *rt = skb_rtable(skb);
356
357 if (rt && rt->rt_iif)
358 return rt->rt_iif;
359
360 return skb->skb_iif;
361}
362
363static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
364{
365 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
366 struct net *net = dev_net(dst->dev);
367
368 if (hoplimit == 0)
369 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
370 return hoplimit;
371}
372
373static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
374 __be32 daddr)
375{
376 struct neighbour *neigh;
377
378 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
379 if (unlikely(!neigh))
380 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
381
382 return neigh;
383}
384
385static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
386 struct sk_buff *skb,
387 bool *is_v6gw)
388{
389 struct net_device *dev = rt->dst.dev;
390 struct neighbour *neigh;
391
392 if (likely(rt->rt_gw_family == AF_INET)) {
393 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
394 } else if (rt->rt_gw_family == AF_INET6) {
395 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
396 *is_v6gw = true;
397 } else {
398 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
399 }
400 return neigh;
401}
402
403#endif /* _ROUTE_H */