xref: /openbmc/linux/include/net/route.h (revision 0f9b4c3ca5fdf3e177266ef994071b1a03f07318)
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  #define RTO_ONLINK	0x01
39  
40  #define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
41  #define RT_CONN_FLAGS_TOS(sk,tos)   (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
42  
ip_sock_rt_scope(const struct sock * sk)43  static inline __u8 ip_sock_rt_scope(const struct sock *sk)
44  {
45  	if (sock_flag(sk, SOCK_LOCALROUTE))
46  		return RT_SCOPE_LINK;
47  
48  	return RT_SCOPE_UNIVERSE;
49  }
50  
ip_sock_rt_tos(const struct sock * sk)51  static inline __u8 ip_sock_rt_tos(const struct sock *sk)
52  {
53  	return RT_TOS(inet_sk(sk)->tos);
54  }
55  
56  struct ip_tunnel_info;
57  struct fib_nh;
58  struct fib_info;
59  struct uncached_list;
60  struct rtable {
61  	struct dst_entry	dst;
62  
63  	int			rt_genid;
64  	unsigned int		rt_flags;
65  	__u16			rt_type;
66  	__u8			rt_is_input;
67  	__u8			rt_uses_gateway;
68  
69  	int			rt_iif;
70  
71  	u8			rt_gw_family;
72  	/* Info on neighbour */
73  	union {
74  		__be32		rt_gw4;
75  		struct in6_addr	rt_gw6;
76  	};
77  
78  	/* Miscellaneous cached information */
79  	u32			rt_mtu_locked:1,
80  				rt_pmtu:31;
81  };
82  
rt_is_input_route(const struct rtable * rt)83  static inline bool rt_is_input_route(const struct rtable *rt)
84  {
85  	return rt->rt_is_input != 0;
86  }
87  
rt_is_output_route(const struct rtable * rt)88  static inline bool rt_is_output_route(const struct rtable *rt)
89  {
90  	return rt->rt_is_input == 0;
91  }
92  
rt_nexthop(const struct rtable * rt,__be32 daddr)93  static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
94  {
95  	if (rt->rt_gw_family == AF_INET)
96  		return rt->rt_gw4;
97  	return daddr;
98  }
99  
100  struct ip_rt_acct {
101  	__u32 	o_bytes;
102  	__u32 	o_packets;
103  	__u32 	i_bytes;
104  	__u32 	i_packets;
105  };
106  
107  struct rt_cache_stat {
108          unsigned int in_slow_tot;
109          unsigned int in_slow_mc;
110          unsigned int in_no_route;
111          unsigned int in_brd;
112          unsigned int in_martian_dst;
113          unsigned int in_martian_src;
114          unsigned int out_slow_tot;
115          unsigned int out_slow_mc;
116  };
117  
118  extern struct ip_rt_acct __percpu *ip_rt_acct;
119  
120  struct in_device;
121  
122  int ip_rt_init(void);
123  void rt_cache_flush(struct net *net);
124  void rt_flush_dev(struct net_device *dev);
125  struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
126  					const struct sk_buff *skb);
127  struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
128  					    struct fib_result *res,
129  					    const struct sk_buff *skb);
130  
__ip_route_output_key(struct net * net,struct flowi4 * flp)131  static inline struct rtable *__ip_route_output_key(struct net *net,
132  						   struct flowi4 *flp)
133  {
134  	return ip_route_output_key_hash(net, flp, NULL);
135  }
136  
137  struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
138  				    const struct sock *sk);
139  struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
140  				      struct net_device *dev,
141  				      struct net *net, __be32 *saddr,
142  				      const struct ip_tunnel_info *info,
143  				      u8 protocol, bool use_cache);
144  
145  struct dst_entry *ipv4_blackhole_route(struct net *net,
146  				       struct dst_entry *dst_orig);
147  
ip_route_output_key(struct net * net,struct flowi4 * flp)148  static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
149  {
150  	return ip_route_output_flow(net, flp, NULL);
151  }
152  
ip_route_output(struct net * net,__be32 daddr,__be32 saddr,u8 tos,int oif)153  static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
154  					     __be32 saddr, u8 tos, int oif)
155  {
156  	struct flowi4 fl4 = {
157  		.flowi4_oif = oif,
158  		.flowi4_tos = tos,
159  		.daddr = daddr,
160  		.saddr = saddr,
161  	};
162  	return ip_route_output_key(net, &fl4);
163  }
164  
ip_route_output_ports(struct net * net,struct flowi4 * fl4,const struct sock * sk,__be32 daddr,__be32 saddr,__be16 dport,__be16 sport,__u8 proto,__u8 tos,int oif)165  static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
166  						   const struct sock *sk,
167  						   __be32 daddr, __be32 saddr,
168  						   __be16 dport, __be16 sport,
169  						   __u8 proto, __u8 tos, int oif)
170  {
171  	flowi4_init_output(fl4, oif, sk ? READ_ONCE(sk->sk_mark) : 0, tos,
172  			   RT_SCOPE_UNIVERSE, proto,
173  			   sk ? inet_sk_flowi_flags(sk) : 0,
174  			   daddr, saddr, dport, sport, sock_net_uid(net, sk));
175  	if (sk)
176  		security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
177  	return ip_route_output_flow(net, fl4, sk);
178  }
179  
ip_route_output_gre(struct net * net,struct flowi4 * fl4,__be32 daddr,__be32 saddr,__be32 gre_key,__u8 tos,int oif)180  static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
181  						 __be32 daddr, __be32 saddr,
182  						 __be32 gre_key, __u8 tos, int oif)
183  {
184  	memset(fl4, 0, sizeof(*fl4));
185  	fl4->flowi4_oif = oif;
186  	fl4->daddr = daddr;
187  	fl4->saddr = saddr;
188  	fl4->flowi4_tos = tos;
189  	fl4->flowi4_proto = IPPROTO_GRE;
190  	fl4->fl4_gre_key = gre_key;
191  	return ip_route_output_key(net, fl4);
192  }
193  int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
194  			  u8 tos, struct net_device *dev,
195  			  struct in_device *in_dev, u32 *itag);
196  int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
197  			 u8 tos, struct net_device *devin);
198  int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
199  		      u8 tos, struct net_device *devin,
200  		      const struct sk_buff *hint);
201  
ip_route_input(struct sk_buff * skb,__be32 dst,__be32 src,dscp_t dscp,struct net_device * devin)202  static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
203  				 dscp_t dscp, struct net_device *devin)
204  {
205  	int err;
206  
207  	rcu_read_lock();
208  	err = ip_route_input_noref(skb, dst, src, inet_dscp_to_dsfield(dscp),
209  				   devin);
210  	if (!err) {
211  		skb_dst_force(skb);
212  		if (!skb_dst(skb))
213  			err = -EINVAL;
214  	}
215  	rcu_read_unlock();
216  
217  	return err;
218  }
219  
220  void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
221  		      u8 protocol);
222  void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
223  void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
224  void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
225  void ip_rt_send_redirect(struct sk_buff *skb);
226  
227  unsigned int inet_addr_type(struct net *net, __be32 addr);
228  unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
229  unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
230  				__be32 addr);
231  unsigned int inet_addr_type_dev_table(struct net *net,
232  				      const struct net_device *dev,
233  				      __be32 addr);
234  void ip_rt_multicast_event(struct in_device *);
235  int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
236  void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
237  struct rtable *rt_dst_alloc(struct net_device *dev,
238  			    unsigned int flags, u16 type, bool noxfrm);
239  struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt);
240  
241  struct in_ifaddr;
242  void fib_add_ifaddr(struct in_ifaddr *);
243  void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
244  void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
245  
246  void rt_add_uncached_list(struct rtable *rt);
247  void rt_del_uncached_list(struct rtable *rt);
248  
249  int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
250  		       u32 table_id, struct fib_info *fi,
251  		       int *fa_index, int fa_start, unsigned int flags);
252  
ip_rt_put(struct rtable * rt)253  static inline void ip_rt_put(struct rtable *rt)
254  {
255  	/* dst_release() accepts a NULL parameter.
256  	 * We rely on dst being first structure in struct rtable
257  	 */
258  	BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
259  	dst_release(&rt->dst);
260  }
261  
262  #define IPTOS_RT_MASK	(IPTOS_TOS_MASK & ~3)
263  
264  extern const __u8 ip_tos2prio[16];
265  
rt_tos2priority(u8 tos)266  static inline char rt_tos2priority(u8 tos)
267  {
268  	return ip_tos2prio[IPTOS_TOS(tos)>>1];
269  }
270  
271  /* ip_route_connect() and ip_route_newports() work in tandem whilst
272   * binding a socket for a new outgoing connection.
273   *
274   * In order to use IPSEC properly, we must, in the end, have a
275   * route that was looked up using all available keys including source
276   * and destination ports.
277   *
278   * However, if a source port needs to be allocated (the user specified
279   * a wildcard source port) we need to obtain addressing information
280   * in order to perform that allocation.
281   *
282   * So ip_route_connect() looks up a route using wildcarded source and
283   * destination ports in the key, simply so that we can get a pair of
284   * addresses to use for port allocation.
285   *
286   * Later, once the ports are allocated, ip_route_newports() will make
287   * another route lookup if needed to make sure we catch any IPSEC
288   * rules keyed on the port information.
289   *
290   * The callers allocate the flow key on their stack, and must pass in
291   * the same flowi4 object to both the ip_route_connect() and the
292   * ip_route_newports() calls.
293   */
294  
ip_route_connect_init(struct flowi4 * fl4,__be32 dst,__be32 src,int oif,u8 protocol,__be16 sport,__be16 dport,const struct sock * sk)295  static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
296  					 __be32 src, int oif, u8 protocol,
297  					 __be16 sport, __be16 dport,
298  					 const struct sock *sk)
299  {
300  	__u8 flow_flags = 0;
301  
302  	if (inet_test_bit(TRANSPARENT, sk))
303  		flow_flags |= FLOWI_FLAG_ANYSRC;
304  
305  	flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk),
306  			   ip_sock_rt_scope(sk), protocol, flow_flags, dst,
307  			   src, dport, sport, sk->sk_uid);
308  }
309  
ip_route_connect(struct flowi4 * fl4,__be32 dst,__be32 src,int oif,u8 protocol,__be16 sport,__be16 dport,const struct sock * sk)310  static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
311  					      __be32 src, int oif, u8 protocol,
312  					      __be16 sport, __be16 dport,
313  					      const struct sock *sk)
314  {
315  	struct net *net = sock_net(sk);
316  	struct rtable *rt;
317  
318  	ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
319  
320  	if (!dst || !src) {
321  		rt = __ip_route_output_key(net, fl4);
322  		if (IS_ERR(rt))
323  			return rt;
324  		ip_rt_put(rt);
325  		flowi4_update_output(fl4, oif, fl4->daddr, fl4->saddr);
326  	}
327  	security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
328  	return ip_route_output_flow(net, fl4, sk);
329  }
330  
ip_route_newports(struct flowi4 * fl4,struct rtable * rt,__be16 orig_sport,__be16 orig_dport,__be16 sport,__be16 dport,const struct sock * sk)331  static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
332  					       __be16 orig_sport, __be16 orig_dport,
333  					       __be16 sport, __be16 dport,
334  					       const struct sock *sk)
335  {
336  	if (sport != orig_sport || dport != orig_dport) {
337  		fl4->fl4_dport = dport;
338  		fl4->fl4_sport = sport;
339  		ip_rt_put(rt);
340  		flowi4_update_output(fl4, sk->sk_bound_dev_if, fl4->daddr,
341  				     fl4->saddr);
342  		security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
343  		return ip_route_output_flow(sock_net(sk), fl4, sk);
344  	}
345  	return rt;
346  }
347  
inet_iif(const struct sk_buff * skb)348  static inline int inet_iif(const struct sk_buff *skb)
349  {
350  	struct rtable *rt = skb_rtable(skb);
351  
352  	if (rt && rt->rt_iif)
353  		return rt->rt_iif;
354  
355  	return skb->skb_iif;
356  }
357  
ip4_dst_hoplimit(const struct dst_entry * dst)358  static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
359  {
360  	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
361  
362  	if (hoplimit == 0) {
363  		const struct net *net;
364  
365  		rcu_read_lock();
366  		net = dev_net_rcu(dst->dev);
367  		hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
368  		rcu_read_unlock();
369  	}
370  	return hoplimit;
371  }
372  
ip_neigh_gw4(struct net_device * dev,__be32 daddr)373  static 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  
ip_neigh_for_gw(struct rtable * rt,struct sk_buff * skb,bool * is_v6gw)385  static 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 */
404