include/net/ip6_fib.h - kernel/msm-5.4 - Gitiles

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  *	Linux INET6 implementation
  *
  *	Authors:
  *	Pedro Roque		<roque@di.fc.ul.pt>
  */

 #ifndef _IP6_FIB_H
 #define _IP6_FIB_H

 #include <linux/ipv6_route.h>
 #include <linux/rtnetlink.h>
 #include <linux/spinlock.h>
 #include <linux/notifier.h>
 #include <net/dst.h>
 #include <net/flow.h>
 #include <net/ip_fib.h>
 #include <net/netlink.h>
 #include <net/inetpeer.h>
 #include <net/fib_notifier.h>

 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 #define FIB6_TABLE_HASHSZ 256
 #else
 #define FIB6_TABLE_HASHSZ 1
 #endif

 #define RT6_DEBUG 2

 #if RT6_DEBUG >= 3
 #define RT6_TRACE(x...) pr_debug(x)
 #else
 #define RT6_TRACE(x...) do { ; } while (0)
 #endif

 struct rt6_info;
 struct fib6_info;

 struct fib6_config {
 	u32		fc_table;
 	u32		fc_metric;
 	int		fc_dst_len;
 	int		fc_src_len;
 	int		fc_ifindex;
 	u32		fc_flags;
 	u32		fc_protocol;
 	u16		fc_type;        /* only 8 bits are used */
 	u16		fc_delete_all_nh : 1,
 			fc_ignore_dev_down:1,
 			__unused : 14;

 	struct in6_addr	fc_dst;
 	struct in6_addr	fc_src;
 	struct in6_addr	fc_prefsrc;
 	struct in6_addr	fc_gateway;

 	unsigned long	fc_expires;
 	struct nlattr	*fc_mx;
 	int		fc_mx_len;
 	int		fc_mp_len;
 	struct nlattr	*fc_mp;

 	struct nl_info	fc_nlinfo;
 	struct nlattr	*fc_encap;
 	u16		fc_encap_type;
 };

 struct fib6_node {
 	struct fib6_node __rcu	*parent;
 	struct fib6_node __rcu	*left;
 	struct fib6_node __rcu	*right;
 #ifdef CONFIG_IPV6_SUBTREES
 	struct fib6_node __rcu	*subtree;
 #endif
 	struct fib6_info __rcu	*leaf;

 	__u16			fn_bit;		/* bit key */
 	__u16			fn_flags;
 	int			fn_sernum;
 	struct fib6_info __rcu	*rr_ptr;
 	struct rcu_head		rcu;
 };

 struct fib6_gc_args {
 	int			timeout;
 	int			more;
 };

 #ifndef CONFIG_IPV6_SUBTREES
 #define FIB6_SUBTREE(fn)	NULL
 #else
 #define FIB6_SUBTREE(fn)	(rcu_dereference_protected((fn)->subtree, 1))
 #endif

 /*
  *	routing information
  *
  */

 struct rt6key {
 	struct in6_addr	addr;
 	int		plen;
 };

 struct fib6_table;

 struct rt6_exception_bucket {
 	struct hlist_head	chain;
 	int			depth;
 };

 struct rt6_exception {
 	struct hlist_node	hlist;
 	struct rt6_info		*rt6i;
 	unsigned long		stamp;
 	struct rcu_head		rcu;
 };

 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
 #define FIB6_MAX_DEPTH 5

 struct fib6_nh {
 	struct fib_nh_common	nh_common;

 #ifdef CONFIG_IPV6_ROUTER_PREF
 	unsigned long		last_probe;
 #endif
 };

 struct fib6_info {
 	struct fib6_table		*fib6_table;
 	struct fib6_info __rcu		*fib6_next;
 	struct fib6_node __rcu		*fib6_node;

 	/* Multipath routes:
 	 * siblings is a list of fib6_info that have the the same metric/weight,
 	 * destination, but not the same gateway. nsiblings is just a cache
 	 * to speed up lookup.
 	 */
 	struct list_head		fib6_siblings;
 	unsigned int			fib6_nsiblings;

 	refcount_t			fib6_ref;
 	unsigned long			expires;
 	struct dst_metrics		*fib6_metrics;
 #define fib6_pmtu		fib6_metrics->metrics[RTAX_MTU-1]

 	struct rt6key			fib6_dst;
 	u32				fib6_flags;
 	struct rt6key			fib6_src;
 	struct rt6key			fib6_prefsrc;

 	struct rt6_info * __percpu	*rt6i_pcpu;
 	struct rt6_exception_bucket __rcu *rt6i_exception_bucket;

 	u32				fib6_metric;
 	u8				fib6_protocol;
 	u8				fib6_type;
 	u8				exception_bucket_flushed:1,
 					should_flush:1,
 					dst_nocount:1,
 					dst_nopolicy:1,
 					dst_host:1,
 					fib6_destroying:1,
 					unused:2;

 	struct fib6_nh			fib6_nh;
 	struct rcu_head			rcu;
 };

 struct rt6_info {
 	struct dst_entry		dst;
 	struct fib6_info __rcu		*from;

 	struct rt6key			rt6i_dst;
 	struct rt6key			rt6i_src;
 	struct in6_addr			rt6i_gateway;
 	struct inet6_dev		*rt6i_idev;
 	u32				rt6i_flags;

 	struct list_head		rt6i_uncached;
 	struct uncached_list		*rt6i_uncached_list;

 	/* more non-fragment space at head required */
 	unsigned short			rt6i_nfheader_len;
 };

 struct fib6_result {
 	struct fib6_nh		*nh;
 	struct fib6_info	*f6i;
 	u32			fib6_flags;
 	u8			fib6_type;
 	struct rt6_info		*rt6;
 };

 #define for_each_fib6_node_rt_rcu(fn)					\
 	for (rt = rcu_dereference((fn)->leaf); rt;			\
 	     rt = rcu_dereference(rt->fib6_next))

 #define for_each_fib6_walker_rt(w)					\
 	for (rt = (w)->leaf; rt;					\
 	     rt = rcu_dereference_protected(rt->fib6_next, 1))

 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 {
 	return ((struct rt6_info *)dst)->rt6i_idev;
 }

 static inline void fib6_clean_expires(struct fib6_info *f6i)
 {
 	f6i->fib6_flags &= ~RTF_EXPIRES;
 	f6i->expires = 0;
 }

 static inline void fib6_set_expires(struct fib6_info *f6i,
 				    unsigned long expires)
 {
 	f6i->expires = expires;
 	f6i->fib6_flags |= RTF_EXPIRES;
 }

 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 {
 	if (f6i->fib6_flags & RTF_EXPIRES)
 		return time_after(jiffies, f6i->expires);
 	return false;
 }

 /* Function to safely get fn->sernum for passed in rt
  * and store result in passed in cookie.
  * Return true if we can get cookie safely
  * Return false if not
  */
 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
 					u32 *cookie)
 {
 	struct fib6_node *fn;
 	bool status = false;

 	fn = rcu_dereference(f6i->fib6_node);

 	if (fn) {
 		*cookie = fn->fn_sernum;
 		/* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
 		smp_rmb();
 		status = true;
 	}

 	return status;
 }

 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 {
 	struct fib6_info *from;
 	u32 cookie = 0;

 	rcu_read_lock();

 	from = rcu_dereference(rt->from);
 	if (from)
 		fib6_get_cookie_safe(from, &cookie);

 	rcu_read_unlock();

 	return cookie;
 }

 static inline void ip6_rt_put(struct rt6_info *rt)
 {
 	/* dst_release() accepts a NULL parameter.
 	 * We rely on dst being first structure in struct rt6_info
 	 */
 	BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
 	dst_release(&rt->dst);
 }

 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags);
 void fib6_info_destroy_rcu(struct rcu_head *head);

 static inline void fib6_info_hold(struct fib6_info *f6i)
 {
 	refcount_inc(&f6i->fib6_ref);
 }

 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
 {
 	return refcount_inc_not_zero(&f6i->fib6_ref);
 }

 static inline void fib6_info_release(struct fib6_info *f6i)
 {
 	if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
 		call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
 }

 enum fib6_walk_state {
 #ifdef CONFIG_IPV6_SUBTREES
 	FWS_S,
 #endif
 	FWS_L,
 	FWS_R,
 	FWS_C,
 	FWS_U
 };

 struct fib6_walker {
 	struct list_head lh;
 	struct fib6_node *root, *node;
 	struct fib6_info *leaf;
 	enum fib6_walk_state state;
 	unsigned int skip;
 	unsigned int count;
 	int (*func)(struct fib6_walker *);
 	void *args;
 };

 struct rt6_statistics {
 	__u32		fib_nodes;		/* all fib6 nodes */
 	__u32		fib_route_nodes;	/* intermediate nodes */
 	__u32		fib_rt_entries;		/* rt entries in fib table */
 	__u32		fib_rt_cache;		/* cached rt entries in exception table */
 	__u32		fib_discarded_routes;	/* total number of routes delete */

 	/* The following stats are not protected by any lock */
 	atomic_t	fib_rt_alloc;		/* total number of routes alloced */
 	atomic_t	fib_rt_uncache;		/* rt entries in uncached list */
 };

 #define RTN_TL_ROOT	0x0001
 #define RTN_ROOT	0x0002		/* tree root node		*/
 #define RTN_RTINFO	0x0004		/* node with valid routing info	*/

 /*
  *	priority levels (or metrics)
  *
  */


 struct fib6_table {
 	struct hlist_node	tb6_hlist;
 	u32			tb6_id;
 	spinlock_t		tb6_lock;
 	struct fib6_node	tb6_root;
 	struct inet_peer_base	tb6_peers;
 	unsigned int		flags;
 	unsigned int		fib_seq;
 #define RT6_TABLE_HAS_DFLT_ROUTER	BIT(0)
 };

 #define RT6_TABLE_UNSPEC	RT_TABLE_UNSPEC
 #define RT6_TABLE_MAIN		RT_TABLE_MAIN
 #define RT6_TABLE_DFLT		RT6_TABLE_MAIN
 #define RT6_TABLE_INFO		RT6_TABLE_MAIN
 #define RT6_TABLE_PREFIX	RT6_TABLE_MAIN

 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 #define FIB6_TABLE_MIN		1
 #define FIB6_TABLE_MAX		RT_TABLE_MAX
 #define RT6_TABLE_LOCAL		RT_TABLE_LOCAL
 #else
 #define FIB6_TABLE_MIN		RT_TABLE_MAIN
 #define FIB6_TABLE_MAX		FIB6_TABLE_MIN
 #define RT6_TABLE_LOCAL		RT6_TABLE_MAIN
 #endif

 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 					 struct fib6_table *,
 					 struct flowi6 *,
 					 const struct sk_buff *, int);

 struct fib6_entry_notifier_info {
 	struct fib_notifier_info info; /* must be first */
 	struct fib6_info *rt;
 };

 /*
  *	exported functions
  */

 struct fib6_table *fib6_get_table(struct net *net, u32 id);
 struct fib6_table *fib6_new_table(struct net *net, u32 id);
 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 				   const struct sk_buff *skb,
 				   int flags, pol_lookup_t lookup);

 /* called with rcu lock held; can return error pointer
  * caller needs to select path
  */
 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 		struct fib6_result *res, int flags);

 /* called with rcu lock held; caller needs to select path */
 int fib6_table_lookup(struct net *net, struct fib6_table *table,
 		      int oif, struct flowi6 *fl6, struct fib6_result *res,
 		      int strict);

 void fib6_select_path(const struct net *net, struct fib6_result *res,
 		      struct flowi6 *fl6, int oif, bool have_oif_match,
 		      const struct sk_buff *skb, int strict);
 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 				   const struct in6_addr *daddr,
 				   const struct in6_addr *saddr);

 struct fib6_node *fib6_locate(struct fib6_node *root,
 			      const struct in6_addr *daddr, int dst_len,
 			      const struct in6_addr *saddr, int src_len,
 			      bool exact_match);

 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
 		    void *arg);
 void fib6_clean_all_skip_notify(struct net *net,
 				int (*func)(struct fib6_info *, void *arg),
 				void *arg);

 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 	     struct nl_info *info, struct netlink_ext_ack *extack);
 int fib6_del(struct fib6_info *rt, struct nl_info *info);

 static inline
 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 {
 	const struct fib6_info *from;

 	rcu_read_lock();

 	from = rcu_dereference(rt->from);
 	if (from) {
 		*addr = from->fib6_prefsrc.addr;
 	} else {
 		struct in6_addr in6_zero = {};

 		*addr = in6_zero;
 	}

 	rcu_read_unlock();
 }

 static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
 {
 	return f6i->fib6_nh.fib_nh_dev;
 }

 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 		 struct fib6_config *cfg, gfp_t gfp_flags,
 		 struct netlink_ext_ack *extack);
 void fib6_nh_release(struct fib6_nh *fib6_nh);

 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 		     unsigned int flags);

 void fib6_run_gc(unsigned long expires, struct net *net, bool force);

 void fib6_gc_cleanup(void);

 int fib6_init(void);

 struct ipv6_route_iter {
 	struct seq_net_private p;
 	struct fib6_walker w;
 	loff_t skip;
 	struct fib6_table *tbl;
 	int sernum;
 };

 extern const struct seq_operations ipv6_route_seq_ops;

 int call_fib6_notifier(struct notifier_block *nb, struct net *net,
 		       enum fib_event_type event_type,
 		       struct fib_notifier_info *info);
 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
 			struct fib_notifier_info *info);

 int __net_init fib6_notifier_init(struct net *net);
 void __net_exit fib6_notifier_exit(struct net *net);

 unsigned int fib6_tables_seq_read(struct net *net);
 int fib6_tables_dump(struct net *net, struct notifier_block *nb);

 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);

 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 {
 	return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
 }

 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 int fib6_rules_init(void);
 void fib6_rules_cleanup(void);
 bool fib6_rule_default(const struct fib_rule *rule);
 int fib6_rules_dump(struct net *net, struct notifier_block *nb);
 unsigned int fib6_rules_seq_read(struct net *net);

 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 						 struct sk_buff *skb,
 						 struct flowi6 *fl6,
 						 struct flow_keys *flkeys)
 {
 	unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;

 	if (!net->ipv6.fib6_rules_require_fldissect)
 		return false;

 	skb_flow_dissect_flow_keys(skb, flkeys, flag);
 	fl6->fl6_sport = flkeys->ports.src;
 	fl6->fl6_dport = flkeys->ports.dst;
 	fl6->flowi6_proto = flkeys->basic.ip_proto;

 	return true;
 }
 #else
 static inline int               fib6_rules_init(void)
 {
 	return 0;
 }
 static inline void              fib6_rules_cleanup(void)
 {
 	return ;
 }
 static inline bool fib6_rule_default(const struct fib_rule *rule)
 {
 	return true;
 }
 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
 {
 	return 0;
 }
 static inline unsigned int fib6_rules_seq_read(struct net *net)
 {
 	return 0;
 }
 static inline bool fib6_rules_early_flow_dissect(struct net *net,
 						 struct sk_buff *skb,
 						 struct flowi6 *fl6,
 						 struct flow_keys *flkeys)
 {
 	return false;
 }
 #endif
 #endif
	/* SPDX-License-Identifier: GPL-2.0-or-later */
	/*
	* Linux INET6 implementation
	*
	* Authors:
	* Pedro Roque <roque@di.fc.ul.pt>
	*/

	#ifndef _IP6_FIB_H
	#define _IP6_FIB_H

	#include <linux/ipv6_route.h>
	#include <linux/rtnetlink.h>
	#include <linux/spinlock.h>
	#include <linux/notifier.h>
	#include <net/dst.h>
	#include <net/flow.h>
	#include <net/ip_fib.h>
	#include <net/netlink.h>
	#include <net/inetpeer.h>
	#include <net/fib_notifier.h>

	#ifdef CONFIG_IPV6_MULTIPLE_TABLES
	#define FIB6_TABLE_HASHSZ 256
	#else
	#define FIB6_TABLE_HASHSZ 1
	#endif

	#define RT6_DEBUG 2

	#if RT6_DEBUG >= 3
	#define RT6_TRACE(x...) pr_debug(x)
	#else
	#define RT6_TRACE(x...) do { ; } while (0)
	#endif

	struct rt6_info;
	struct fib6_info;

	struct fib6_config {
	u32 fc_table;
	u32 fc_metric;
	int fc_dst_len;
	int fc_src_len;
	int fc_ifindex;
	u32 fc_flags;
	u32 fc_protocol;
	u16 fc_type; /* only 8 bits are used */
	u16 fc_delete_all_nh : 1,
	fc_ignore_dev_down:1,
	__unused : 14;

	struct in6_addr fc_dst;
	struct in6_addr fc_src;
	struct in6_addr fc_prefsrc;
	struct in6_addr fc_gateway;

	unsigned long fc_expires;
	struct nlattr *fc_mx;
	int fc_mx_len;
	int fc_mp_len;
	struct nlattr *fc_mp;

	struct nl_info fc_nlinfo;
	struct nlattr *fc_encap;
	u16 fc_encap_type;
	};

	struct fib6_node {
	struct fib6_node __rcu *parent;
	struct fib6_node __rcu *left;
	struct fib6_node __rcu *right;
	#ifdef CONFIG_IPV6_SUBTREES
	struct fib6_node __rcu *subtree;
	#endif
	struct fib6_info __rcu *leaf;

	__u16 fn_bit; /* bit key */
	__u16 fn_flags;
	int fn_sernum;
	struct fib6_info __rcu *rr_ptr;
	struct rcu_head rcu;
	};

	struct fib6_gc_args {
	int timeout;
	int more;
	};

	#ifndef CONFIG_IPV6_SUBTREES
	#define FIB6_SUBTREE(fn) NULL
	#else
	#define FIB6_SUBTREE(fn) (rcu_dereference_protected((fn)->subtree, 1))
	#endif

	/*
	* routing information
	*
	*/

	struct rt6key {
	struct in6_addr addr;
	int plen;
	};

	struct fib6_table;

	struct rt6_exception_bucket {
	struct hlist_head chain;
	int depth;
	};

	struct rt6_exception {
	struct hlist_node hlist;
	struct rt6_info *rt6i;
	unsigned long stamp;
	struct rcu_head rcu;
	};

	#define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
	#define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
	#define FIB6_MAX_DEPTH 5

	struct fib6_nh {
	struct fib_nh_common nh_common;

	#ifdef CONFIG_IPV6_ROUTER_PREF
	unsigned long last_probe;
	#endif
	};

	struct fib6_info {
	struct fib6_table *fib6_table;
	struct fib6_info __rcu *fib6_next;
	struct fib6_node __rcu *fib6_node;

	/* Multipath routes:
	* siblings is a list of fib6_info that have the the same metric/weight,
	* destination, but not the same gateway. nsiblings is just a cache
	* to speed up lookup.
	*/
	struct list_head fib6_siblings;
	unsigned int fib6_nsiblings;

	refcount_t fib6_ref;
	unsigned long expires;
	struct dst_metrics *fib6_metrics;
	#define fib6_pmtu fib6_metrics->metrics[RTAX_MTU-1]

	struct rt6key fib6_dst;
	u32 fib6_flags;
	struct rt6key fib6_src;
	struct rt6key fib6_prefsrc;

	struct rt6_info * __percpu *rt6i_pcpu;
	struct rt6_exception_bucket __rcu *rt6i_exception_bucket;

	u32 fib6_metric;
	u8 fib6_protocol;
	u8 fib6_type;
	u8 exception_bucket_flushed:1,
	should_flush:1,
	dst_nocount:1,
	dst_nopolicy:1,
	dst_host:1,
	fib6_destroying:1,
	unused:2;

	struct fib6_nh fib6_nh;
	struct rcu_head rcu;
	};

	struct rt6_info {
	struct dst_entry dst;
	struct fib6_info __rcu *from;

	struct rt6key rt6i_dst;
	struct rt6key rt6i_src;
	struct in6_addr rt6i_gateway;
	struct inet6_dev *rt6i_idev;
	u32 rt6i_flags;

	struct list_head rt6i_uncached;
	struct uncached_list *rt6i_uncached_list;

	/* more non-fragment space at head required */
	unsigned short rt6i_nfheader_len;
	};

	struct fib6_result {
	struct fib6_nh *nh;
	struct fib6_info *f6i;
	u32 fib6_flags;
	u8 fib6_type;
	struct rt6_info *rt6;
	};

	#define for_each_fib6_node_rt_rcu(fn) \
	for (rt = rcu_dereference((fn)->leaf); rt; \
	rt = rcu_dereference(rt->fib6_next))

	#define for_each_fib6_walker_rt(w) \
	for (rt = (w)->leaf; rt; \
	rt = rcu_dereference_protected(rt->fib6_next, 1))

	static inline struct inet6_dev ip6_dst_idev(struct dst_entry dst)
	{
	return ((struct rt6_info *)dst)->rt6i_idev;
	}

	static inline void fib6_clean_expires(struct fib6_info *f6i)
	{
	f6i->fib6_flags &= ~RTF_EXPIRES;
	f6i->expires = 0;
	}

	static inline void fib6_set_expires(struct fib6_info *f6i,
	unsigned long expires)
	{
	f6i->expires = expires;
	f6i->fib6_flags \|= RTF_EXPIRES;
	}

	static inline bool fib6_check_expired(const struct fib6_info *f6i)
	{
	if (f6i->fib6_flags & RTF_EXPIRES)
	return time_after(jiffies, f6i->expires);
	return false;
	}

	/* Function to safely get fn->sernum for passed in rt
	* and store result in passed in cookie.
	* Return true if we can get cookie safely
	* Return false if not
	*/
	static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
	u32 *cookie)
	{
	struct fib6_node *fn;
	bool status = false;

	fn = rcu_dereference(f6i->fib6_node);

	if (fn) {
	*cookie = fn->fn_sernum;
	/* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
	smp_rmb();
	status = true;
	}

	return status;
	}

	static inline u32 rt6_get_cookie(const struct rt6_info *rt)
	{
	struct fib6_info *from;
	u32 cookie = 0;

	rcu_read_lock();

	from = rcu_dereference(rt->from);
	if (from)
	fib6_get_cookie_safe(from, &cookie);

	rcu_read_unlock();

	return cookie;
	}

	static inline void ip6_rt_put(struct rt6_info *rt)
	{
	/* dst_release() accepts a NULL parameter.
	* We rely on dst being first structure in struct rt6_info
	*/
	BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
	dst_release(&rt->dst);
	}

	struct fib6_info *fib6_info_alloc(gfp_t gfp_flags);
	void fib6_info_destroy_rcu(struct rcu_head *head);

	static inline void fib6_info_hold(struct fib6_info *f6i)
	{
	refcount_inc(&f6i->fib6_ref);
	}

	static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
	{
	return refcount_inc_not_zero(&f6i->fib6_ref);
	}

	static inline void fib6_info_release(struct fib6_info *f6i)
	{
	if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
	call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
	}

	enum fib6_walk_state {
	#ifdef CONFIG_IPV6_SUBTREES
	FWS_S,
	#endif
	FWS_L,
	FWS_R,
	FWS_C,
	FWS_U
	};

	struct fib6_walker {
	struct list_head lh;
	struct fib6_node root, node;
	struct fib6_info *leaf;
	enum fib6_walk_state state;
	unsigned int skip;
	unsigned int count;
	int (func)(struct fib6_walker );
	void *args;
	};

	struct rt6_statistics {
	__u32 fib_nodes; /* all fib6 nodes */
	__u32 fib_route_nodes; /* intermediate nodes */
	__u32 fib_rt_entries; /* rt entries in fib table */
	__u32 fib_rt_cache; /* cached rt entries in exception table */
	__u32 fib_discarded_routes; /* total number of routes delete */

	/* The following stats are not protected by any lock */
	atomic_t fib_rt_alloc; /* total number of routes alloced */
	atomic_t fib_rt_uncache; /* rt entries in uncached list */
	};

	#define RTN_TL_ROOT 0x0001
	#define RTN_ROOT 0x0002 /* tree root node */
	#define RTN_RTINFO 0x0004 /* node with valid routing info */

	/*
	* priority levels (or metrics)
	*
	*/


	struct fib6_table {
	struct hlist_node tb6_hlist;
	u32 tb6_id;
	spinlock_t tb6_lock;
	struct fib6_node tb6_root;
	struct inet_peer_base tb6_peers;
	unsigned int flags;
	unsigned int fib_seq;
	#define RT6_TABLE_HAS_DFLT_ROUTER BIT(0)
	};

	#define RT6_TABLE_UNSPEC RT_TABLE_UNSPEC
	#define RT6_TABLE_MAIN RT_TABLE_MAIN
	#define RT6_TABLE_DFLT RT6_TABLE_MAIN
	#define RT6_TABLE_INFO RT6_TABLE_MAIN
	#define RT6_TABLE_PREFIX RT6_TABLE_MAIN

	#ifdef CONFIG_IPV6_MULTIPLE_TABLES
	#define FIB6_TABLE_MIN 1
	#define FIB6_TABLE_MAX RT_TABLE_MAX
	#define RT6_TABLE_LOCAL RT_TABLE_LOCAL
	#else
	#define FIB6_TABLE_MIN RT_TABLE_MAIN
	#define FIB6_TABLE_MAX FIB6_TABLE_MIN
	#define RT6_TABLE_LOCAL RT6_TABLE_MAIN
	#endif

	typedef struct rt6_info (pol_lookup_t)(struct net *,
	struct fib6_table *,
	struct flowi6 *,
	const struct sk_buff *, int);

	struct fib6_entry_notifier_info {
	struct fib_notifier_info info; /* must be first */
	struct fib6_info *rt;
	};

	/*
	* exported functions
	*/

	struct fib6_table fib6_get_table(struct net net, u32 id);
	struct fib6_table fib6_new_table(struct net net, u32 id);
	struct dst_entry fib6_rule_lookup(struct net net, struct flowi6 *fl6,
	const struct sk_buff *skb,
	int flags, pol_lookup_t lookup);

	/* called with rcu lock held; can return error pointer
	* caller needs to select path
	*/
	int fib6_lookup(struct net net, int oif, struct flowi6 fl6,
	struct fib6_result *res, int flags);

	/* called with rcu lock held; caller needs to select path */
	int fib6_table_lookup(struct net net, struct fib6_table table,
	int oif, struct flowi6 fl6, struct fib6_result res,
	int strict);

	void fib6_select_path(const struct net net, struct fib6_result res,
	struct flowi6 *fl6, int oif, bool have_oif_match,
	const struct sk_buff *skb, int strict);
	struct fib6_node fib6_node_lookup(struct fib6_node root,
	const struct in6_addr *daddr,
	const struct in6_addr *saddr);

	struct fib6_node fib6_locate(struct fib6_node root,
	const struct in6_addr *daddr, int dst_len,
	const struct in6_addr *saddr, int src_len,
	bool exact_match);

	void fib6_clean_all(struct net net, int (func)(struct fib6_info , void arg),
	void *arg);
	void fib6_clean_all_skip_notify(struct net *net,
	int (func)(struct fib6_info , void *arg),
	void *arg);

	int fib6_add(struct fib6_node root, struct fib6_info rt,
	struct nl_info info, struct netlink_ext_ack extack);
	int fib6_del(struct fib6_info rt, struct nl_info info);

	static inline
	void rt6_get_prefsrc(const struct rt6_info rt, struct in6_addr addr)
	{
	const struct fib6_info *from;

	rcu_read_lock();

	from = rcu_dereference(rt->from);
	if (from) {
	*addr = from->fib6_prefsrc.addr;
	} else {
	struct in6_addr in6_zero = {};

	*addr = in6_zero;
	}

	rcu_read_unlock();
	}

	static inline struct net_device fib6_info_nh_dev(const struct fib6_info f6i)
	{
	return f6i->fib6_nh.fib_nh_dev;
	}

	int fib6_nh_init(struct net net, struct fib6_nh fib6_nh,
	struct fib6_config *cfg, gfp_t gfp_flags,
	struct netlink_ext_ack *extack);
	void fib6_nh_release(struct fib6_nh *fib6_nh);

	void inet6_rt_notify(int event, struct fib6_info rt, struct nl_info info,
	unsigned int flags);

	void fib6_run_gc(unsigned long expires, struct net *net, bool force);

	void fib6_gc_cleanup(void);

	int fib6_init(void);

	struct ipv6_route_iter {
	struct seq_net_private p;
	struct fib6_walker w;
	loff_t skip;
	struct fib6_table *tbl;
	int sernum;
	};

	extern const struct seq_operations ipv6_route_seq_ops;

	int call_fib6_notifier(struct notifier_block nb, struct net net,
	enum fib_event_type event_type,
	struct fib_notifier_info *info);
	int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
	struct fib_notifier_info *info);

	int __net_init fib6_notifier_init(struct net *net);
	void __net_exit fib6_notifier_exit(struct net *net);

	unsigned int fib6_tables_seq_read(struct net *net);
	int fib6_tables_dump(struct net net, struct notifier_block nb);

	void fib6_update_sernum(struct net net, struct fib6_info rt);
	void fib6_update_sernum_upto_root(struct net net, struct fib6_info rt);

	void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
	static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
	{
	return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
	}

	#ifdef CONFIG_IPV6_MULTIPLE_TABLES
	int fib6_rules_init(void);
	void fib6_rules_cleanup(void);
	bool fib6_rule_default(const struct fib_rule *rule);
	int fib6_rules_dump(struct net net, struct notifier_block nb);
	unsigned int fib6_rules_seq_read(struct net *net);

	static inline bool fib6_rules_early_flow_dissect(struct net *net,
	struct sk_buff *skb,
	struct flowi6 *fl6,
	struct flow_keys *flkeys)
	{
	unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;

	if (!net->ipv6.fib6_rules_require_fldissect)
	return false;

	skb_flow_dissect_flow_keys(skb, flkeys, flag);
	fl6->fl6_sport = flkeys->ports.src;
	fl6->fl6_dport = flkeys->ports.dst;
	fl6->flowi6_proto = flkeys->basic.ip_proto;

	return true;
	}
	#else
	static inline int fib6_rules_init(void)
	{
	return 0;
	}
	static inline void fib6_rules_cleanup(void)
	{
	return ;
	}
	static inline bool fib6_rule_default(const struct fib_rule *rule)
	{
	return true;
	}
	static inline int fib6_rules_dump(struct net net, struct notifier_block nb)
	{
	return 0;
	}
	static inline unsigned int fib6_rules_seq_read(struct net *net)
	{
	return 0;
	}
	static inline bool fib6_rules_early_flow_dissect(struct net *net,
	struct sk_buff *skb,
	struct flowi6 *fl6,
	struct flow_keys *flkeys)
	{
	return false;
	}
	#endif
	#endif