Line data Source code
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 :
75 8 : static inline bool rt_is_input_route(const struct rtable *rt)
76 : {
77 8 : return rt->rt_is_input != 0;
78 : }
79 :
80 0 : static inline bool rt_is_output_route(const struct rtable *rt)
81 : {
82 0 : return rt->rt_is_input == 0;
83 : }
84 :
85 0 : static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
86 : {
87 0 : if (rt->rt_gw_family == AF_INET)
88 0 : 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 :
123 58 : static inline struct rtable *__ip_route_output_key(struct net *net,
124 : struct flowi4 *flp)
125 : {
126 58 : 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 rtable *ip_route_output_tunnel(struct sk_buff *skb,
132 : struct net_device *dev,
133 : struct net *net, __be32 *saddr,
134 : const struct ip_tunnel_info *info,
135 : u8 protocol, bool use_cache);
136 :
137 : struct dst_entry *ipv4_blackhole_route(struct net *net,
138 : struct dst_entry *dst_orig);
139 :
140 0 : static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
141 : {
142 0 : return ip_route_output_flow(net, flp, NULL);
143 : }
144 :
145 0 : static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
146 : __be32 saddr, u8 tos, int oif)
147 : {
148 0 : struct flowi4 fl4 = {
149 : .flowi4_oif = oif,
150 : .flowi4_tos = tos,
151 : .daddr = daddr,
152 : .saddr = saddr,
153 : };
154 0 : return ip_route_output_key(net, &fl4);
155 : }
156 :
157 4 : static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
158 : struct sock *sk,
159 : __be32 daddr, __be32 saddr,
160 : __be16 dport, __be16 sport,
161 : __u8 proto, __u8 tos, int oif)
162 : {
163 12 : flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
164 : RT_SCOPE_UNIVERSE, proto,
165 4 : sk ? inet_sk_flowi_flags(sk) : 0,
166 : daddr, saddr, dport, sport, sock_net_uid(net, sk));
167 4 : if (sk)
168 4 : security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
169 4 : return ip_route_output_flow(net, fl4, sk);
170 : }
171 :
172 : static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
173 : __be32 daddr, __be32 saddr,
174 : __be32 gre_key, __u8 tos, int oif)
175 : {
176 : memset(fl4, 0, sizeof(*fl4));
177 : fl4->flowi4_oif = oif;
178 : fl4->daddr = daddr;
179 : fl4->saddr = saddr;
180 : fl4->flowi4_tos = tos;
181 : fl4->flowi4_proto = IPPROTO_GRE;
182 : fl4->fl4_gre_key = gre_key;
183 : return ip_route_output_key(net, fl4);
184 : }
185 : int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
186 : u8 tos, struct net_device *dev,
187 : struct in_device *in_dev, u32 *itag);
188 : int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
189 : u8 tos, struct net_device *devin);
190 : int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
191 : u8 tos, struct net_device *devin,
192 : struct fib_result *res);
193 :
194 : int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
195 : u8 tos, struct net_device *devin,
196 : const struct sk_buff *hint);
197 :
198 0 : static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
199 : u8 tos, struct net_device *devin)
200 : {
201 0 : int err;
202 :
203 0 : rcu_read_lock();
204 0 : err = ip_route_input_noref(skb, dst, src, tos, devin);
205 0 : if (!err) {
206 0 : skb_dst_force(skb);
207 0 : if (!skb_dst(skb))
208 0 : err = -EINVAL;
209 : }
210 0 : rcu_read_unlock();
211 :
212 0 : return err;
213 : }
214 :
215 : void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
216 : u8 protocol);
217 : void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
218 : void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
219 : void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
220 : void ip_rt_send_redirect(struct sk_buff *skb);
221 :
222 : unsigned int inet_addr_type(struct net *net, __be32 addr);
223 : unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
224 : unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
225 : __be32 addr);
226 : unsigned int inet_addr_type_dev_table(struct net *net,
227 : const struct net_device *dev,
228 : __be32 addr);
229 : void ip_rt_multicast_event(struct in_device *);
230 : int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
231 : void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
232 : struct rtable *rt_dst_alloc(struct net_device *dev,
233 : unsigned int flags, u16 type,
234 : bool nopolicy, bool noxfrm);
235 : struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
236 :
237 : struct in_ifaddr;
238 : void fib_add_ifaddr(struct in_ifaddr *);
239 : void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
240 : void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
241 :
242 : void rt_add_uncached_list(struct rtable *rt);
243 : void rt_del_uncached_list(struct rtable *rt);
244 :
245 : int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
246 : u32 table_id, struct fib_info *fi,
247 : int *fa_index, int fa_start, unsigned int flags);
248 :
249 27 : static inline void ip_rt_put(struct rtable *rt)
250 : {
251 : /* dst_release() accepts a NULL parameter.
252 : * We rely on dst being first structure in struct rtable
253 : */
254 27 : BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
255 14 : dst_release(&rt->dst);
256 14 : }
257 :
258 : #define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
259 :
260 : extern const __u8 ip_tos2prio[16];
261 :
262 4 : static inline char rt_tos2priority(u8 tos)
263 : {
264 4 : return ip_tos2prio[IPTOS_TOS(tos)>>1];
265 : }
266 :
267 : /* ip_route_connect() and ip_route_newports() work in tandem whilst
268 : * binding a socket for a new outgoing connection.
269 : *
270 : * In order to use IPSEC properly, we must, in the end, have a
271 : * route that was looked up using all available keys including source
272 : * and destination ports.
273 : *
274 : * However, if a source port needs to be allocated (the user specified
275 : * a wildcard source port) we need to obtain addressing information
276 : * in order to perform that allocation.
277 : *
278 : * So ip_route_connect() looks up a route using wildcarded source and
279 : * destination ports in the key, simply so that we can get a pair of
280 : * addresses to use for port allocation.
281 : *
282 : * Later, once the ports are allocated, ip_route_newports() will make
283 : * another route lookup if needed to make sure we catch any IPSEC
284 : * rules keyed on the port information.
285 : *
286 : * The callers allocate the flow key on their stack, and must pass in
287 : * the same flowi4 object to both the ip_route_connect() and the
288 : * ip_route_newports() calls.
289 : */
290 :
291 33 : static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
292 : u32 tos, int oif, u8 protocol,
293 : __be16 sport, __be16 dport,
294 : struct sock *sk)
295 : {
296 33 : __u8 flow_flags = 0;
297 :
298 33 : if (inet_sk(sk)->transparent)
299 0 : flow_flags |= FLOWI_FLAG_ANYSRC;
300 :
301 33 : flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
302 : protocol, flow_flags, dst, src, dport, sport,
303 : sk->sk_uid);
304 : }
305 :
306 33 : static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
307 : __be32 dst, __be32 src, u32 tos,
308 : int oif, u8 protocol,
309 : __be16 sport, __be16 dport,
310 : struct sock *sk)
311 : {
312 33 : struct net *net = sock_net(sk);
313 33 : struct rtable *rt;
314 :
315 33 : ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
316 : sport, dport, sk);
317 :
318 33 : if (!dst || !src) {
319 33 : rt = __ip_route_output_key(net, fl4);
320 33 : if (IS_ERR(rt))
321 : return rt;
322 13 : ip_rt_put(rt);
323 13 : flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
324 : }
325 13 : security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
326 13 : return ip_route_output_flow(net, fl4, sk);
327 : }
328 :
329 0 : static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
330 : __be16 orig_sport, __be16 orig_dport,
331 : __be16 sport, __be16 dport,
332 : struct sock *sk)
333 : {
334 0 : if (sport != orig_sport || dport != orig_dport) {
335 0 : fl4->fl4_dport = dport;
336 0 : fl4->fl4_sport = sport;
337 0 : ip_rt_put(rt);
338 0 : flowi4_update_output(fl4, sk->sk_bound_dev_if,
339 0 : RT_CONN_FLAGS(sk), fl4->daddr,
340 : fl4->saddr);
341 0 : security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
342 0 : return ip_route_output_flow(sock_net(sk), fl4, sk);
343 : }
344 : return rt;
345 : }
346 :
347 495 : static inline int inet_iif(const struct sk_buff *skb)
348 : {
349 495 : struct rtable *rt = skb_rtable(skb);
350 :
351 495 : if (rt && rt->rt_iif)
352 : return rt->rt_iif;
353 :
354 495 : return skb->skb_iif;
355 : }
356 :
357 444 : static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
358 : {
359 444 : int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
360 444 : struct net *net = dev_net(dst->dev);
361 :
362 444 : if (hoplimit == 0)
363 444 : hoplimit = net->ipv4.sysctl_ip_default_ttl;
364 : return hoplimit;
365 : }
366 :
367 446 : static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
368 : __be32 daddr)
369 : {
370 446 : struct neighbour *neigh;
371 :
372 446 : neigh = __ipv4_neigh_lookup_noref(dev, daddr);
373 446 : if (unlikely(!neigh))
374 2 : neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
375 :
376 446 : return neigh;
377 : }
378 :
379 444 : static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
380 : struct sk_buff *skb,
381 : bool *is_v6gw)
382 : {
383 444 : struct net_device *dev = rt->dst.dev;
384 444 : struct neighbour *neigh;
385 :
386 444 : if (likely(rt->rt_gw_family == AF_INET)) {
387 0 : neigh = ip_neigh_gw4(dev, rt->rt_gw4);
388 444 : } else if (rt->rt_gw_family == AF_INET6) {
389 0 : neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
390 0 : *is_v6gw = true;
391 : } else {
392 444 : neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
393 : }
394 444 : return neigh;
395 : }
396 :
397 : #endif /* _ROUTE_H */
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