[deliverable/linux.git] / include / net / ip_fib.h

/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET  is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Definitions for the Forwarding Information Base.
 *
 * Authors:	A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */

#ifndef _NET_IP_FIB_H
#define _NET_IP_FIB_H

#include <net/flow.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <net/fib_rules.h>
#include <net/inetpeer.h>
#include <linux/percpu.h>

struct fib_config {
	u8			fc_dst_len;
	u8			fc_tos;
	u8			fc_protocol;
	u8			fc_scope;
	u8			fc_type;
	/* 3 bytes unused */
	u32			fc_table;
	__be32			fc_dst;
	__be32			fc_gw;
	int			fc_oif;
	u32			fc_flags;
	u32			fc_priority;
	__be32			fc_prefsrc;
	struct nlattr		*fc_mx;
	struct rtnexthop	*fc_mp;
	int			fc_mx_len;
	int			fc_mp_len;
	u32			fc_flow;
	u32			fc_nlflags;
	struct nl_info		fc_nlinfo;
	struct nlattr		*fc_encap;
	u16			fc_encap_type;
};

struct fib_info;
struct rtable;

struct fib_nh_exception {
	struct fib_nh_exception __rcu	*fnhe_next;
	int				fnhe_genid;
	__be32				fnhe_daddr;
	u32				fnhe_pmtu;
	__be32				fnhe_gw;
	unsigned long			fnhe_expires;
	struct rtable __rcu		*fnhe_rth_input;
	struct rtable __rcu		*fnhe_rth_output;
	unsigned long			fnhe_stamp;
	struct rcu_head			rcu;
};

struct fnhe_hash_bucket {
	struct fib_nh_exception __rcu	*chain;
};

#define FNHE_HASH_SHIFT		11
#define FNHE_HASH_SIZE		(1 << FNHE_HASH_SHIFT)
#define FNHE_RECLAIM_DEPTH	5

struct fib_nh {
	struct net_device	*nh_dev;
	struct hlist_node	nh_hash;
	struct fib_info		*nh_parent;
	unsigned int		nh_flags;
	unsigned char		nh_scope;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
	int			nh_weight;
	atomic_t		nh_upper_bound;
#endif
#ifdef CONFIG_IP_ROUTE_CLASSID
	__u32			nh_tclassid;
#endif
	int			nh_oif;
	__be32			nh_gw;
	__be32			nh_saddr;
	int			nh_saddr_genid;
	struct rtable __rcu * __percpu *nh_pcpu_rth_output;
	struct rtable __rcu	*nh_rth_input;
	struct fnhe_hash_bucket	__rcu *nh_exceptions;
	struct lwtunnel_state	*nh_lwtstate;
};

/*
 * This structure contains data shared by many of routes.
 */

struct fib_info {
	struct hlist_node	fib_hash;
	struct hlist_node	fib_lhash;
	struct net		*fib_net;
	int			fib_treeref;
	atomic_t		fib_clntref;
	unsigned int		fib_flags;
	unsigned char		fib_dead;
	unsigned char		fib_protocol;
	unsigned char		fib_scope;
	unsigned char		fib_type;
	__be32			fib_prefsrc;
	u32			fib_priority;
	u32			*fib_metrics;
#define fib_mtu fib_metrics[RTAX_MTU-1]
#define fib_window fib_metrics[RTAX_WINDOW-1]
#define fib_rtt fib_metrics[RTAX_RTT-1]
#define fib_advmss fib_metrics[RTAX_ADVMSS-1]
	int			fib_nhs;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
	int			fib_weight;
#endif
	struct rcu_head		rcu;
	struct fib_nh		fib_nh[0];
#define fib_dev		fib_nh[0].nh_dev
};


#ifdef CONFIG_IP_MULTIPLE_TABLES
struct fib_rule;
#endif

struct fib_table;
struct fib_result {
	unsigned char	prefixlen;
	unsigned char	nh_sel;
	unsigned char	type;
	unsigned char	scope;
	u32		tclassid;
	struct fib_info *fi;
	struct fib_table *table;
	struct hlist_head *fa_head;
};

struct fib_result_nl {
	__be32		fl_addr;   /* To be looked up*/
	u32		fl_mark;
	unsigned char	fl_tos;
	unsigned char   fl_scope;
	unsigned char   tb_id_in;

	unsigned char   tb_id;      /* Results */
	unsigned char	prefixlen;
	unsigned char	nh_sel;
	unsigned char	type;
	unsigned char	scope;
	int             err;      
};

#ifdef CONFIG_IP_ROUTE_MULTIPATH
#define FIB_RES_NH(res)		((res).fi->fib_nh[(res).nh_sel])
#else /* CONFIG_IP_ROUTE_MULTIPATH */
#define FIB_RES_NH(res)		((res).fi->fib_nh[0])
#endif /* CONFIG_IP_ROUTE_MULTIPATH */

#ifdef CONFIG_IP_MULTIPLE_TABLES
#define FIB_TABLE_HASHSZ 256
#else
#define FIB_TABLE_HASHSZ 2
#endif

__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh);

#define FIB_RES_SADDR(net, res)				\
	((FIB_RES_NH(res).nh_saddr_genid ==		\
	  atomic_read(&(net)->ipv4.dev_addr_genid)) ?	\
	 FIB_RES_NH(res).nh_saddr :			\
	 fib_info_update_nh_saddr((net), &FIB_RES_NH(res)))
#define FIB_RES_GW(res)			(FIB_RES_NH(res).nh_gw)
#define FIB_RES_DEV(res)		(FIB_RES_NH(res).nh_dev)
#define FIB_RES_OIF(res)		(FIB_RES_NH(res).nh_oif)

#define FIB_RES_PREFSRC(net, res)	((res).fi->fib_prefsrc ? : \
					 FIB_RES_SADDR(net, res))

struct fib_table {
	struct hlist_node	tb_hlist;
	u32			tb_id;
	int			tb_num_default;
	struct rcu_head		rcu;
	unsigned long 		*tb_data;
	unsigned long		__data[0];
};

int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
		     struct fib_result *res, int fib_flags);
int fib_table_insert(struct fib_table *, struct fib_config *);
int fib_table_delete(struct fib_table *, struct fib_config *);
int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
		   struct netlink_callback *cb);
int fib_table_flush(struct fib_table *table);
struct fib_table *fib_trie_unmerge(struct fib_table *main_tb);
void fib_table_flush_external(struct fib_table *table);
void fib_free_table(struct fib_table *tb);

#ifndef CONFIG_IP_MULTIPLE_TABLES

#define TABLE_LOCAL_INDEX	(RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
#define TABLE_MAIN_INDEX	(RT_TABLE_MAIN  & (FIB_TABLE_HASHSZ - 1))

static inline struct fib_table *fib_get_table(struct net *net, u32 id)
{
	struct hlist_node *tb_hlist;
	struct hlist_head *ptr;

	ptr = id == RT_TABLE_LOCAL ?
		&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
		&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];

	tb_hlist = rcu_dereference_rtnl(hlist_first_rcu(ptr));

	return hlist_entry(tb_hlist, struct fib_table, tb_hlist);
}

static inline struct fib_table *fib_new_table(struct net *net, u32 id)
{
	return fib_get_table(net, id);
}

static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
			     struct fib_result *res, unsigned int flags)
{
	struct fib_table *tb;
	int err = -ENETUNREACH;

	rcu_read_lock();

	tb = fib_get_table(net, RT_TABLE_MAIN);
	if (tb)
		err = fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF);

	if (err == -EAGAIN)
		err = -ENETUNREACH;

	rcu_read_unlock();

	return err;
}

#else /* CONFIG_IP_MULTIPLE_TABLES */
int __net_init fib4_rules_init(struct net *net);
void __net_exit fib4_rules_exit(struct net *net);

struct fib_table *fib_new_table(struct net *net, u32 id);
struct fib_table *fib_get_table(struct net *net, u32 id);

int __fib_lookup(struct net *net, struct flowi4 *flp,
		 struct fib_result *res, unsigned int flags);

static inline int fib_lookup(struct net *net, struct flowi4 *flp,
			     struct fib_result *res, unsigned int flags)
{
	struct fib_table *tb;
	int err = -ENETUNREACH;

	flags |= FIB_LOOKUP_NOREF;
	if (net->ipv4.fib_has_custom_rules)
		return __fib_lookup(net, flp, res, flags);

	rcu_read_lock();

	res->tclassid = 0;

	tb = rcu_dereference_rtnl(net->ipv4.fib_main);
	if (tb)
		err = fib_table_lookup(tb, flp, res, flags);

	if (!err)
		goto out;

	tb = rcu_dereference_rtnl(net->ipv4.fib_default);
	if (tb)
		err = fib_table_lookup(tb, flp, res, flags);

out:
	if (err == -EAGAIN)
		err = -ENETUNREACH;

	rcu_read_unlock();

	return err;
}

#endif /* CONFIG_IP_MULTIPLE_TABLES */

/* Exported by fib_frontend.c */
extern const struct nla_policy rtm_ipv4_policy[];
void ip_fib_init(void);
__be32 fib_compute_spec_dst(struct sk_buff *skb);
int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
			u8 tos, int oif, struct net_device *dev,
			struct in_device *idev, u32 *itag);
void fib_select_default(const struct flowi4 *flp, struct fib_result *res);
#ifdef CONFIG_IP_ROUTE_CLASSID
static inline int fib_num_tclassid_users(struct net *net)
{
	return net->ipv4.fib_num_tclassid_users;
}
#else
static inline int fib_num_tclassid_users(struct net *net)
{
	return 0;
}
#endif
int fib_unmerge(struct net *net);
void fib_flush_external(struct net *net);

/* Exported by fib_semantics.c */
int ip_fib_check_default(__be32 gw, struct net_device *dev);
int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force);
int fib_sync_down_addr(struct net *net, __be32 local);
int fib_sync_up(struct net_device *dev, unsigned int nh_flags);

extern u32 fib_multipath_secret __read_mostly;

static inline int fib_multipath_hash(__be32 saddr, __be32 daddr)
{
	return jhash_2words((__force u32)saddr, (__force u32)daddr,
			    fib_multipath_secret) >> 1;
}

void fib_select_multipath(struct fib_result *res, int hash);
void fib_select_path(struct net *net, struct fib_result *res,
		     struct flowi4 *fl4, int mp_hash);

/* Exported by fib_trie.c */
void fib_trie_init(void);
struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);

static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
#ifdef CONFIG_IP_MULTIPLE_TABLES
	u32 rtag;
#endif
	*itag = FIB_RES_NH(*res).nh_tclassid<<16;
#ifdef CONFIG_IP_MULTIPLE_TABLES
	rtag = res->tclassid;
	if (*itag == 0)
		*itag = (rtag<<16);
	*itag |= (rtag>>16);
#endif
#endif
}

void free_fib_info(struct fib_info *fi);

static inline void fib_info_put(struct fib_info *fi)
{
	if (atomic_dec_and_test(&fi->fib_clntref))
		free_fib_info(fi);
}

#ifdef CONFIG_PROC_FS
int __net_init fib_proc_init(struct net *net);
void __net_exit fib_proc_exit(struct net *net);
#else
static inline int fib_proc_init(struct net *net)
{
	return 0;
}
static inline void fib_proc_exit(struct net *net)
{
}
#endif

#endif  /* _NET_FIB_H */
Commit	Line	Data
	1	/*
	2	* INET An implementation of the TCP/IP protocol suite for the LINUX
	3	* operating system. INET is implemented using the BSD Socket
	4	* interface as the means of communication with the user level.
	5	*
	6	* Definitions for the Forwarding Information Base.
	7	*
	8	* Authors: A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
	9	*
	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License
	12	* as published by the Free Software Foundation; either version
	13	* 2 of the License, or (at your option) any later version.
	14	*/
	15
	16	#ifndef _NET_IP_FIB_H
	17	#define _NET_IP_FIB_H
	18
	19	#include <net/flow.h>
	20	#include <linux/seq_file.h>
	21	#include <linux/rcupdate.h>
	22	#include <net/fib_rules.h>
	23	#include <net/inetpeer.h>
	24	#include <linux/percpu.h>
	25
	26	struct fib_config {
	27	u8 fc_dst_len;
	28	u8 fc_tos;
	29	u8 fc_protocol;
	30	u8 fc_scope;
	31	u8 fc_type;
	32	/* 3 bytes unused */
	33	u32 fc_table;
	34	__be32 fc_dst;
	35	__be32 fc_gw;
	36	int fc_oif;
	37	u32 fc_flags;
	38	u32 fc_priority;
	39	__be32 fc_prefsrc;
	40	struct nlattr *fc_mx;
	41	struct rtnexthop *fc_mp;
	42	int fc_mx_len;
	43	int fc_mp_len;
	44	u32 fc_flow;
	45	u32 fc_nlflags;
	46	struct nl_info fc_nlinfo;
	47	struct nlattr *fc_encap;
	48	u16 fc_encap_type;
	49	};
	50
	51	struct fib_info;
	52	struct rtable;
	53
	54	struct fib_nh_exception {
	55	struct fib_nh_exception __rcu *fnhe_next;
	56	int fnhe_genid;
	57	__be32 fnhe_daddr;
	58	u32 fnhe_pmtu;
	59	__be32 fnhe_gw;
	60	unsigned long fnhe_expires;
	61	struct rtable __rcu *fnhe_rth_input;
	62	struct rtable __rcu *fnhe_rth_output;
	63	unsigned long fnhe_stamp;
	64	struct rcu_head rcu;
	65	};
	66
	67	struct fnhe_hash_bucket {
	68	struct fib_nh_exception __rcu *chain;
	69	};
	70
	71	#define FNHE_HASH_SHIFT 11
	72	#define FNHE_HASH_SIZE (1 << FNHE_HASH_SHIFT)
	73	#define FNHE_RECLAIM_DEPTH 5
	74
	75	struct fib_nh {
	76	struct net_device *nh_dev;
	77	struct hlist_node nh_hash;
	78	struct fib_info *nh_parent;
	79	unsigned int nh_flags;
	80	unsigned char nh_scope;
	81	#ifdef CONFIG_IP_ROUTE_MULTIPATH
	82	int nh_weight;
	83	atomic_t nh_upper_bound;
	84	#endif
	85	#ifdef CONFIG_IP_ROUTE_CLASSID
	86	__u32 nh_tclassid;
	87	#endif
	88	int nh_oif;
	89	__be32 nh_gw;
	90	__be32 nh_saddr;
	91	int nh_saddr_genid;
	92	struct rtable __rcu * __percpu *nh_pcpu_rth_output;
	93	struct rtable __rcu *nh_rth_input;
	94	struct fnhe_hash_bucket __rcu *nh_exceptions;
	95	struct lwtunnel_state *nh_lwtstate;
	96	};
	97
	98	/*
	99	* This structure contains data shared by many of routes.
	100	*/
	101
	102	struct fib_info {
	103	struct hlist_node fib_hash;
	104	struct hlist_node fib_lhash;
	105	struct net *fib_net;
	106	int fib_treeref;
	107	atomic_t fib_clntref;
	108	unsigned int fib_flags;
	109	unsigned char fib_dead;
	110	unsigned char fib_protocol;
	111	unsigned char fib_scope;
	112	unsigned char fib_type;
	113	__be32 fib_prefsrc;
	114	u32 fib_priority;
	115	u32 *fib_metrics;
	116	#define fib_mtu fib_metrics[RTAX_MTU-1]
	117	#define fib_window fib_metrics[RTAX_WINDOW-1]
	118	#define fib_rtt fib_metrics[RTAX_RTT-1]
	119	#define fib_advmss fib_metrics[RTAX_ADVMSS-1]
	120	int fib_nhs;
	121	#ifdef CONFIG_IP_ROUTE_MULTIPATH
	122	int fib_weight;
	123	#endif
	124	struct rcu_head rcu;
	125	struct fib_nh fib_nh[0];
	126	#define fib_dev fib_nh[0].nh_dev
	127	};
	128
	129
	130	#ifdef CONFIG_IP_MULTIPLE_TABLES
	131	struct fib_rule;
	132	#endif
	133
	134	struct fib_table;
	135	struct fib_result {
	136	unsigned char prefixlen;
	137	unsigned char nh_sel;
	138	unsigned char type;
	139	unsigned char scope;
	140	u32 tclassid;
	141	struct fib_info *fi;
	142	struct fib_table *table;
	143	struct hlist_head *fa_head;
	144	};
	145
	146	struct fib_result_nl {
	147	__be32 fl_addr; /* To be looked up*/
	148	u32 fl_mark;
	149	unsigned char fl_tos;
	150	unsigned char fl_scope;
	151	unsigned char tb_id_in;
	152
	153	unsigned char tb_id; /* Results */
	154	unsigned char prefixlen;
	155	unsigned char nh_sel;
	156	unsigned char type;
	157	unsigned char scope;
	158	int err;
	159	};
	160
	161	#ifdef CONFIG_IP_ROUTE_MULTIPATH
	162	#define FIB_RES_NH(res) ((res).fi->fib_nh[(res).nh_sel])
	163	#else /* CONFIG_IP_ROUTE_MULTIPATH */
	164	#define FIB_RES_NH(res) ((res).fi->fib_nh[0])
	165	#endif /* CONFIG_IP_ROUTE_MULTIPATH */
	166
	167	#ifdef CONFIG_IP_MULTIPLE_TABLES
	168	#define FIB_TABLE_HASHSZ 256
	169	#else
	170	#define FIB_TABLE_HASHSZ 2
	171	#endif
	172
	173	__be32 fib_info_update_nh_saddr(struct net net, struct fib_nh nh);
	174
	175	#define FIB_RES_SADDR(net, res) \
	176	((FIB_RES_NH(res).nh_saddr_genid == \
	177	atomic_read(&(net)->ipv4.dev_addr_genid)) ? \
	178	FIB_RES_NH(res).nh_saddr : \
	179	fib_info_update_nh_saddr((net), &FIB_RES_NH(res)))
	180	#define FIB_RES_GW(res) (FIB_RES_NH(res).nh_gw)
	181	#define FIB_RES_DEV(res) (FIB_RES_NH(res).nh_dev)
	182	#define FIB_RES_OIF(res) (FIB_RES_NH(res).nh_oif)
	183
	184	#define FIB_RES_PREFSRC(net, res) ((res).fi->fib_prefsrc ? : \
	185	FIB_RES_SADDR(net, res))
	186
	187	struct fib_table {
	188	struct hlist_node tb_hlist;
	189	u32 tb_id;
	190	int tb_num_default;
	191	struct rcu_head rcu;
	192	unsigned long *tb_data;
	193	unsigned long __data[0];
	194	};
	195
	196	int fib_table_lookup(struct fib_table tb, const struct flowi4 flp,
	197	struct fib_result *res, int fib_flags);
	198	int fib_table_insert(struct fib_table , struct fib_config );
	199	int fib_table_delete(struct fib_table , struct fib_config );
	200	int fib_table_dump(struct fib_table table, struct sk_buff skb,
	201	struct netlink_callback *cb);
	202	int fib_table_flush(struct fib_table *table);
	203	struct fib_table fib_trie_unmerge(struct fib_table main_tb);
	204	void fib_table_flush_external(struct fib_table *table);
	205	void fib_free_table(struct fib_table *tb);
	206
	207	#ifndef CONFIG_IP_MULTIPLE_TABLES
	208
	209	#define TABLE_LOCAL_INDEX (RT_TABLE_LOCAL & (FIB_TABLE_HASHSZ - 1))
	210	#define TABLE_MAIN_INDEX (RT_TABLE_MAIN & (FIB_TABLE_HASHSZ - 1))
	211
	212	static inline struct fib_table fib_get_table(struct net net, u32 id)
	213	{
	214	struct hlist_node *tb_hlist;
	215	struct hlist_head *ptr;
	216
	217	ptr = id == RT_TABLE_LOCAL ?
	218	&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
	219	&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];
	220
	221	tb_hlist = rcu_dereference_rtnl(hlist_first_rcu(ptr));
	222
	223	return hlist_entry(tb_hlist, struct fib_table, tb_hlist);
	224	}
	225
	226	static inline struct fib_table fib_new_table(struct net net, u32 id)
	227	{
	228	return fib_get_table(net, id);
	229	}
	230
	231	static inline int fib_lookup(struct net net, const struct flowi4 flp,
	232	struct fib_result *res, unsigned int flags)
	233	{
	234	struct fib_table *tb;
	235	int err = -ENETUNREACH;
	236
	237	rcu_read_lock();
	238
	239	tb = fib_get_table(net, RT_TABLE_MAIN);
	240	if (tb)
	241	err = fib_table_lookup(tb, flp, res, flags \| FIB_LOOKUP_NOREF);
	242
	243	if (err == -EAGAIN)
	244	err = -ENETUNREACH;
	245
	246	rcu_read_unlock();
	247
	248	return err;
	249	}
	250
	251	#else /* CONFIG_IP_MULTIPLE_TABLES */
	252	int __net_init fib4_rules_init(struct net *net);
	253	void __net_exit fib4_rules_exit(struct net *net);
	254
	255	struct fib_table fib_new_table(struct net net, u32 id);
	256	struct fib_table fib_get_table(struct net net, u32 id);
	257
	258	int __fib_lookup(struct net net, struct flowi4 flp,
	259	struct fib_result *res, unsigned int flags);
	260
	261	static inline int fib_lookup(struct net net, struct flowi4 flp,
	262	struct fib_result *res, unsigned int flags)
	263	{
	264	struct fib_table *tb;
	265	int err = -ENETUNREACH;
	266
	267	flags \|= FIB_LOOKUP_NOREF;
	268	if (net->ipv4.fib_has_custom_rules)
	269	return __fib_lookup(net, flp, res, flags);
	270
	271	rcu_read_lock();
	272
	273	res->tclassid = 0;
	274
	275	tb = rcu_dereference_rtnl(net->ipv4.fib_main);
	276	if (tb)
	277	err = fib_table_lookup(tb, flp, res, flags);
	278
	279	if (!err)
	280	goto out;
	281
	282	tb = rcu_dereference_rtnl(net->ipv4.fib_default);
	283	if (tb)
	284	err = fib_table_lookup(tb, flp, res, flags);
	285
	286	out:
	287	if (err == -EAGAIN)
	288	err = -ENETUNREACH;
	289
	290	rcu_read_unlock();
	291
	292	return err;
	293	}
	294
	295	#endif /* CONFIG_IP_MULTIPLE_TABLES */
	296
	297	/* Exported by fib_frontend.c */
	298	extern const struct nla_policy rtm_ipv4_policy[];
	299	void ip_fib_init(void);
	300	__be32 fib_compute_spec_dst(struct sk_buff *skb);
	301	int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
	302	u8 tos, int oif, struct net_device *dev,
	303	struct in_device idev, u32 itag);
	304	void fib_select_default(const struct flowi4 flp, struct fib_result res);
	305	#ifdef CONFIG_IP_ROUTE_CLASSID
	306	static inline int fib_num_tclassid_users(struct net *net)
	307	{
	308	return net->ipv4.fib_num_tclassid_users;
	309	}
	310	#else
	311	static inline int fib_num_tclassid_users(struct net *net)
	312	{
	313	return 0;
	314	}
	315	#endif
	316	int fib_unmerge(struct net *net);
	317	void fib_flush_external(struct net *net);
	318
	319	/* Exported by fib_semantics.c */
	320	int ip_fib_check_default(__be32 gw, struct net_device *dev);
	321	int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force);
	322	int fib_sync_down_addr(struct net *net, __be32 local);
	323	int fib_sync_up(struct net_device *dev, unsigned int nh_flags);
	324
	325	extern u32 fib_multipath_secret __read_mostly;
	326
	327	static inline int fib_multipath_hash(__be32 saddr, __be32 daddr)
	328	{
	329	return jhash_2words((__force u32)saddr, (__force u32)daddr,
	330	fib_multipath_secret) >> 1;
	331	}
	332
	333	void fib_select_multipath(struct fib_result *res, int hash);
	334	void fib_select_path(struct net net, struct fib_result res,
	335	struct flowi4 *fl4, int mp_hash);
	336
	337	/* Exported by fib_trie.c */
	338	void fib_trie_init(void);
	339	struct fib_table fib_trie_table(u32 id, struct fib_table alias);
	340
	341	static inline void fib_combine_itag(u32 itag, const struct fib_result res)
	342	{
	343	#ifdef CONFIG_IP_ROUTE_CLASSID
	344	#ifdef CONFIG_IP_MULTIPLE_TABLES
	345	u32 rtag;
	346	#endif
	347	itag = FIB_RES_NH(res).nh_tclassid<<16;
	348	#ifdef CONFIG_IP_MULTIPLE_TABLES
	349	rtag = res->tclassid;
	350	if (*itag == 0)
	351	*itag = (rtag<<16);
	352	*itag \|= (rtag>>16);
	353	#endif
	354	#endif
	355	}
	356
	357	void free_fib_info(struct fib_info *fi);
	358
	359	static inline void fib_info_put(struct fib_info *fi)
	360	{
	361	if (atomic_dec_and_test(&fi->fib_clntref))
	362	free_fib_info(fi);
	363	}
	364
	365	#ifdef CONFIG_PROC_FS
	366	int __net_init fib_proc_init(struct net *net);
	367	void __net_exit fib_proc_exit(struct net *net);
	368	#else
	369	static inline int fib_proc_init(struct net *net)
	370	{
	371	return 0;
	372	}
	373	static inline void fib_proc_exit(struct net *net)
	374	{
	375	}
	376	#endif
	377
	378	#endif /* _NET_FIB_H */