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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 <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
40static 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
48static inline __u8 ip_sock_rt_tos(const struct sock *sk)
49{
50 return READ_ONCE(inet_sk(sk)->tos) & INET_DSCP_MASK;
51}
52
53struct ip_tunnel_info;
54struct fib_nh;
55struct fib_info;
56struct uncached_list;
57struct 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 */
86static inline struct rtable *skb_rtable(const struct sk_buff *skb)
87{
88 return dst_rtable(skb_dst(skb));
89}
90
91static inline bool rt_is_input_route(const struct rtable *rt)
92{
93 return rt->rt_is_input != 0;
94}
95
96static inline bool rt_is_output_route(const struct rtable *rt)
97{
98 return rt->rt_is_input == 0;
99}
100
101static 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
108struct ip_rt_acct {
109 __u32 o_bytes;
110 __u32 o_packets;
111 __u32 i_bytes;
112 __u32 i_packets;
113};
114
115struct 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
126extern struct ip_rt_acct __percpu *ip_rt_acct;
127
128struct in_device;
129
130int ip_rt_init(void);
131void rt_cache_flush(struct net *net);
132void rt_flush_dev(struct net_device *dev);
133
134static 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_uid(sk));
157 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
158}
159
160struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
161 const struct sk_buff *skb);
162struct 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
166static 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
172struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
173 const struct sock *sk);
174struct dst_entry *ipv4_blackhole_route(struct net *net,
175 struct dst_entry *dst_orig);
176
177static 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 */
186static 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_dscp = dscp,
193 .flowi4_scope = scope,
194 .daddr = daddr,
195 .saddr = saddr,
196 };
197
198 return ip_route_output_key(net, &fl4);
199}
200
201static 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
216enum skb_drop_reason
217ip_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);
220enum skb_drop_reason
221ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
222 dscp_t dscp, struct net_device *dev);
223enum skb_drop_reason
224ip_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
228static inline enum skb_drop_reason
229ip_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
246void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
247 u8 protocol);
248void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
249void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
250void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
251void ip_rt_send_redirect(struct sk_buff *skb);
252
253unsigned int inet_addr_type(struct net *net, __be32 addr);
254unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
255unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
256 __be32 addr);
257unsigned int inet_addr_type_dev_table(struct net *net,
258 const struct net_device *dev,
259 __be32 addr);
260void ip_rt_multicast_event(struct in_device *);
261int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
262void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
263struct rtable *rt_dst_alloc(struct net_device *dev,
264 unsigned int flags, u16 type, bool noxfrm);
265struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
266
267struct in_ifaddr;
268void fib_add_ifaddr(struct in_ifaddr *);
269void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
270void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
271
272void rt_add_uncached_list(struct rtable *rt);
273void rt_del_uncached_list(struct rtable *rt);
274
275int 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
279static 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
288extern const __u8 ip_tos2prio[16];
289
290static 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
319static 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 if (IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) && !sport)
330 flow_flags |= FLOWI_FLAG_ANY_SPORT;
331
332 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk),
333 ip_sock_rt_scope(sk), protocol, flow_flags, dst,
334 src, dport, sport, sk_uid(sk));
335}
336
337static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
338 __be32 src, int oif, u8 protocol,
339 __be16 sport, __be16 dport,
340 const struct sock *sk)
341{
342 struct net *net = sock_net(sk);
343 struct rtable *rt;
344
345 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
346
347 if (!dst || !src) {
348 rt = __ip_route_output_key(net, fl4);
349 if (IS_ERR(rt))
350 return rt;
351 ip_rt_put(rt);
352 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr);
353 }
354 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
355 return ip_route_output_flow(net, fl4, sk);
356}
357
358static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
359 __be16 orig_sport, __be16 orig_dport,
360 __be16 sport, __be16 dport,
361 const struct sock *sk)
362{
363 if (sport != orig_sport || dport != orig_dport) {
364 fl4->fl4_dport = dport;
365 fl4->fl4_sport = sport;
366 ip_rt_put(rt);
367 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr,
368 fl4->saddr);
369 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
370 return ip_route_output_flow(sock_net(sk), fl4, sk);
371 }
372 return rt;
373}
374
375static inline int inet_iif(const struct sk_buff *skb)
376{
377 struct rtable *rt = skb_rtable(skb);
378
379 if (rt && rt->rt_iif)
380 return rt->rt_iif;
381
382 return skb->skb_iif;
383}
384
385static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
386{
387 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
388
389 if (hoplimit == 0) {
390 const struct net *net;
391
392 rcu_read_lock();
393 net = dst_dev_net_rcu(dst);
394 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
395 rcu_read_unlock();
396 }
397 return hoplimit;
398}
399
400static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
401 __be32 daddr)
402{
403 struct neighbour *neigh;
404
405 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
406 if (unlikely(!neigh))
407 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
408
409 return neigh;
410}
411
412static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
413 struct sk_buff *skb,
414 bool *is_v6gw)
415{
416 struct net_device *dev = rt->dst.dev;
417 struct neighbour *neigh;
418
419 if (likely(rt->rt_gw_family == AF_INET)) {
420 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
421 } else if (rt->rt_gw_family == AF_INET6) {
422 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
423 *is_v6gw = true;
424 } else {
425 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
426 }
427 return neigh;
428}
429
430#endif /* _ROUTE_H */