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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, dscp_t dscp,
160 int oif, __u8 scope)
161{
162 struct flowi4 fl4 = {
163 .flowi4_oif = oif,
164 .flowi4_tos = inet_dscp_to_dsfield(dscp),
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}
201
202enum skb_drop_reason
203ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
204 dscp_t dscp, struct net_device *dev,
205 struct in_device *in_dev, u32 *itag);
206enum skb_drop_reason
207ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
208 dscp_t dscp, struct net_device *dev);
209enum skb_drop_reason
210ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
211 dscp_t dscp, struct net_device *dev,
212 const struct sk_buff *hint);
213
214static inline enum skb_drop_reason
215ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src, dscp_t dscp,
216 struct net_device *devin)
217{
218 enum skb_drop_reason reason;
219
220 rcu_read_lock();
221 reason = ip_route_input_noref(skb, dst, src, dscp, devin);
222 if (!reason) {
223 skb_dst_force(skb);
224 if (!skb_dst(skb))
225 reason = SKB_DROP_REASON_NOT_SPECIFIED;
226 }
227 rcu_read_unlock();
228
229 return reason;
230}
231
232void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
233 u8 protocol);
234void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
235void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
236void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
237void ip_rt_send_redirect(struct sk_buff *skb);
238
239unsigned int inet_addr_type(struct net *net, __be32 addr);
240unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
241unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
242 __be32 addr);
243unsigned int inet_addr_type_dev_table(struct net *net,
244 const struct net_device *dev,
245 __be32 addr);
246void ip_rt_multicast_event(struct in_device *);
247int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
248void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
249struct rtable *rt_dst_alloc(struct net_device *dev,
250 unsigned int flags, u16 type, bool noxfrm);
251struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
252
253struct in_ifaddr;
254void fib_add_ifaddr(struct in_ifaddr *);
255void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
256void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
257
258void rt_add_uncached_list(struct rtable *rt);
259void rt_del_uncached_list(struct rtable *rt);
260
261int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
262 u32 table_id, struct fib_info *fi,
263 int *fa_index, int fa_start, unsigned int flags);
264
265static inline void ip_rt_put(struct rtable *rt)
266{
267 /* dst_release() accepts a NULL parameter.
268 * We rely on dst being first structure in struct rtable
269 */
270 BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
271 dst_release(&rt->dst);
272}
273
274extern const __u8 ip_tos2prio[16];
275
276static inline char rt_tos2priority(u8 tos)
277{
278 return ip_tos2prio[IPTOS_TOS(tos)>>1];
279}
280
281/* ip_route_connect() and ip_route_newports() work in tandem whilst
282 * binding a socket for a new outgoing connection.
283 *
284 * In order to use IPSEC properly, we must, in the end, have a
285 * route that was looked up using all available keys including source
286 * and destination ports.
287 *
288 * However, if a source port needs to be allocated (the user specified
289 * a wildcard source port) we need to obtain addressing information
290 * in order to perform that allocation.
291 *
292 * So ip_route_connect() looks up a route using wildcarded source and
293 * destination ports in the key, simply so that we can get a pair of
294 * addresses to use for port allocation.
295 *
296 * Later, once the ports are allocated, ip_route_newports() will make
297 * another route lookup if needed to make sure we catch any IPSEC
298 * rules keyed on the port information.
299 *
300 * The callers allocate the flow key on their stack, and must pass in
301 * the same flowi4 object to both the ip_route_connect() and the
302 * ip_route_newports() calls.
303 */
304
305static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
306 __be32 src, int oif, u8 protocol,
307 __be16 sport, __be16 dport,
308 const struct sock *sk)
309{
310 __u8 flow_flags = 0;
311
312 if (inet_test_bit(TRANSPARENT, sk))
313 flow_flags |= FLOWI_FLAG_ANYSRC;
314
315 flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk),
316 ip_sock_rt_scope(sk), protocol, flow_flags, dst,
317 src, dport, sport, sk->sk_uid);
318}
319
320static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
321 __be32 src, int oif, u8 protocol,
322 __be16 sport, __be16 dport,
323 const struct sock *sk)
324{
325 struct net *net = sock_net(sk);
326 struct rtable *rt;
327
328 ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
329
330 if (!dst || !src) {
331 rt = __ip_route_output_key(net, fl4);
332 if (IS_ERR(rt))
333 return rt;
334 ip_rt_put(rt);
335 flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr);
336 }
337 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
338 return ip_route_output_flow(net, fl4, sk);
339}
340
341static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
342 __be16 orig_sport, __be16 orig_dport,
343 __be16 sport, __be16 dport,
344 const struct sock *sk)
345{
346 if (sport != orig_sport || dport != orig_dport) {
347 fl4->fl4_dport = dport;
348 fl4->fl4_sport = sport;
349 ip_rt_put(rt);
350 flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr,
351 fl4->saddr);
352 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
353 return ip_route_output_flow(sock_net(sk), fl4, sk);
354 }
355 return rt;
356}
357
358static inline int inet_iif(const struct sk_buff *skb)
359{
360 struct rtable *rt = skb_rtable(skb);
361
362 if (rt && rt->rt_iif)
363 return rt->rt_iif;
364
365 return skb->skb_iif;
366}
367
368static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
369{
370 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
371 struct net *net = dev_net(dst->dev);
372
373 if (hoplimit == 0)
374 hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
375 return hoplimit;
376}
377
378static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
379 __be32 daddr)
380{
381 struct neighbour *neigh;
382
383 neigh = __ipv4_neigh_lookup_noref(dev, (__force u32)daddr);
384 if (unlikely(!neigh))
385 neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
386
387 return neigh;
388}
389
390static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
391 struct sk_buff *skb,
392 bool *is_v6gw)
393{
394 struct net_device *dev = rt->dst.dev;
395 struct neighbour *neigh;
396
397 if (likely(rt->rt_gw_family == AF_INET)) {
398 neigh = ip_neigh_gw4(dev, rt->rt_gw4);
399 } else if (rt->rt_gw_family == AF_INET6) {
400 neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
401 *is_v6gw = true;
402 } else {
403 neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
404 }
405 return neigh;
406}
407
408#endif /* _ROUTE_H */