include/net/ip_fib.h - third_party/kernel - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * 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>
  */

 #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_notifier.h>
 #include <net/fib_rules.h>
 #include <net/inet_dscp.h>
 #include <net/inetpeer.h>
 #include <linux/percpu.h>
 #include <linux/notifier.h>
 #include <linux/refcount.h>
 #include <linux/ip.h>
 #include <linux/in_route.h>

 struct fib_config {
 	u8			fc_dst_len;
 	dscp_t			fc_dscp;
 	u8			fc_protocol;
 	u8			fc_scope;
 	u8			fc_type;
 	u8			fc_gw_family;
 	/* 2 bytes unused */
 	u32			fc_table;
 	__be32			fc_dst;
 	union {
 		__be32		fc_gw4;
 		struct in6_addr	fc_gw6;
 	};
 	int			fc_oif;
 	u32			fc_flags;
 	u32			fc_priority;
 	__be32			fc_prefsrc;
 	u32			fc_nh_id;
 	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;
 	bool				fnhe_mtu_locked;
 	__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_common {
 	struct net_device	*nhc_dev;
 	netdevice_tracker	nhc_dev_tracker;
 	int			nhc_oif;
 	unsigned char		nhc_scope;
 	u8			nhc_family;
 	u8			nhc_gw_family;
 	unsigned char		nhc_flags;
 	struct lwtunnel_state	*nhc_lwtstate;

 	union {
 		__be32          ipv4;
 		struct in6_addr ipv6;
 	} nhc_gw;

 	int			nhc_weight;
 	atomic_t		nhc_upper_bound;

 	/* v4 specific, but allows fib6_nh with v4 routes */
 	struct rtable __rcu * __percpu *nhc_pcpu_rth_output;
 	struct rtable __rcu     *nhc_rth_input;
 	struct fnhe_hash_bucket	__rcu *nhc_exceptions;
 };

 struct fib_nh {
 	struct fib_nh_common	nh_common;
 	struct hlist_node	nh_hash;
 	struct fib_info		*nh_parent;
 #ifdef CONFIG_IP_ROUTE_CLASSID
 	__u32			nh_tclassid;
 #endif
 	__be32			nh_saddr;
 	int			nh_saddr_genid;
 #define fib_nh_family		nh_common.nhc_family
 #define fib_nh_dev		nh_common.nhc_dev
 #define fib_nh_dev_tracker	nh_common.nhc_dev_tracker
 #define fib_nh_oif		nh_common.nhc_oif
 #define fib_nh_flags		nh_common.nhc_flags
 #define fib_nh_lws		nh_common.nhc_lwtstate
 #define fib_nh_scope		nh_common.nhc_scope
 #define fib_nh_gw_family	nh_common.nhc_gw_family
 #define fib_nh_gw4		nh_common.nhc_gw.ipv4
 #define fib_nh_gw6		nh_common.nhc_gw.ipv6
 #define fib_nh_weight		nh_common.nhc_weight
 #define fib_nh_upper_bound	nh_common.nhc_upper_bound
 };

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

 struct nexthop;

 struct fib_info {
 	struct hlist_node	fib_hash;
 	struct hlist_node	fib_lhash;
 	struct list_head	nh_list;
 	struct net		*fib_net;
 	refcount_t		fib_treeref;
 	refcount_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_tb_id;
 	u32			fib_priority;
 	struct dst_metrics	*fib_metrics;
 #define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
 #define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
 #define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
 #define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
 	int			fib_nhs;
 	bool			fib_nh_is_v6;
 	bool			nh_updated;
 	bool			pfsrc_removed;
 	struct nexthop		*nh;
 	struct rcu_head		rcu;
 	struct fib_nh		fib_nh[] __counted_by(fib_nhs);
 };


 #ifdef CONFIG_IP_MULTIPLE_TABLES
 struct fib_rule;
 #endif

 struct fib_table;
 struct fib_result {
 	__be32			prefix;
 	unsigned char		prefixlen;
 	unsigned char		nh_sel;
 	unsigned char		type;
 	unsigned char		scope;
 	u32			tclassid;
 	dscp_t			dscp;
 	struct fib_nh_common	*nhc;
 	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_MULTIPLE_TABLES
 #define FIB_TABLE_HASHSZ 256
 #else
 #define FIB_TABLE_HASHSZ 2
 #endif

 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
 				 unsigned char scope);
 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res);

 #define FIB_RES_NHC(res)		((res).nhc)
 #define FIB_RES_DEV(res)	(FIB_RES_NHC(res)->nhc_dev)
 #define FIB_RES_OIF(res)	(FIB_RES_NHC(res)->nhc_oif)

 struct fib_rt_info {
 	struct fib_info		*fi;
 	u32			tb_id;
 	__be32			dst;
 	int			dst_len;
 	dscp_t			dscp;
 	u8			type;
 	u8			offload:1,
 				trap:1,
 				offload_failed:1,
 				unused:5;
 };

 struct fib_entry_notifier_info {
 	struct fib_notifier_info info; /* must be first */
 	u32 dst;
 	int dst_len;
 	struct fib_info *fi;
 	dscp_t dscp;
 	u8 type;
 	u32 tb_id;
 };

 struct fib_nh_notifier_info {
 	struct fib_notifier_info info; /* must be first */
 	struct fib_nh *fib_nh;
 };

 int call_fib4_notifier(struct notifier_block *nb,
 		       enum fib_event_type event_type,
 		       struct fib_notifier_info *info);
 int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
 			struct fib_notifier_info *info);

 int __net_init fib4_notifier_init(struct net *net);
 void __net_exit fib4_notifier_exit(struct net *net);

 void fib_info_notify_update(struct net *net, struct nl_info *info);
 int fib_notify(struct net *net, struct notifier_block *nb,
 	       struct netlink_ext_ack *extack);

 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[];
 };

 struct fib_dump_filter {
 	u32			table_id;
 	/* filter_set is an optimization that an entry is set */
 	bool			filter_set;
 	bool			dump_routes;
 	bool			dump_exceptions;
 	bool			rtnl_held;
 	unsigned char		protocol;
 	unsigned char		rt_type;
 	unsigned int		flags;
 	struct net_device	*dev;
 };

 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 		     struct fib_result *res, int fib_flags);
 int fib_table_insert(struct net *, struct fib_table *, struct fib_config *,
 		     struct netlink_ext_ack *extack);
 int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
 		     struct netlink_ext_ack *extack);
 int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
 		   struct netlink_callback *cb, struct fib_dump_filter *filter);
 int fib_table_flush(struct net *net, struct fib_table *table, bool flush_all);
 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;
 }

 static inline bool fib4_has_custom_rules(const struct net *net)
 {
 	return false;
 }

 static inline bool fib4_rule_default(const struct fib_rule *rule)
 {
 	return true;
 }

 static inline int fib4_rules_dump(struct net *net, struct notifier_block *nb,
 				  struct netlink_ext_ack *extack)
 {
 	return 0;
 }

 static inline unsigned int fib4_rules_seq_read(struct net *net)
 {
 	return 0;
 }

 static inline bool fib4_rules_early_flow_dissect(struct net *net,
 						 struct sk_buff *skb,
 						 struct flowi4 *fl4,
 						 struct flow_keys *flkeys)
 {
 	return false;
 }
 #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;
 }

 static inline bool fib4_has_custom_rules(const struct net *net)
 {
 	return net->ipv4.fib_has_custom_rules;
 }

 bool fib4_rule_default(const struct fib_rule *rule);
 int fib4_rules_dump(struct net *net, struct notifier_block *nb,
 		    struct netlink_ext_ack *extack);
 unsigned int fib4_rules_seq_read(struct net *net);

 static inline bool fib4_rules_early_flow_dissect(struct net *net,
 						 struct sk_buff *skb,
 						 struct flowi4 *fl4,
 						 struct flow_keys *flkeys)
 {
 	unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;

 	if (!net->ipv4.fib_rules_require_fldissect)
 		return false;

 	memset(flkeys, 0, sizeof(*flkeys));
 	__skb_flow_dissect(net, skb, &flow_keys_dissector,
 			   flkeys, NULL, 0, 0, 0, flag);

 	fl4->fl4_sport = flkeys->ports.src;
 	fl4->fl4_dport = flkeys->ports.dst;
 	fl4->flowi4_proto = flkeys->basic.ip_proto;

 	return true;
 }

 #endif /* CONFIG_IP_MULTIPLE_TABLES */

 static inline bool fib_dscp_masked_match(dscp_t dscp, const struct flowi4 *fl4)
 {
 	return dscp == inet_dsfield_to_dscp(RT_TOS(fl4->flowi4_tos));
 }

 /* Exported by fib_frontend.c */
 extern const struct nla_policy rtm_ipv4_policy[];
 void ip_fib_init(void);
 int fib_gw_from_via(struct fib_config *cfg, struct nlattr *nla,
 		    struct netlink_ext_ack *extack);
 __be32 fib_compute_spec_dst(struct sk_buff *skb);
 bool fib_info_nh_uses_dev(struct fib_info *fi, const struct net_device *dev);
 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);
 #ifdef CONFIG_IP_ROUTE_CLASSID
 static inline int fib_num_tclassid_users(struct net *net)
 {
 	return atomic_read(&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);

 static inline bool nhc_l3mdev_matches_dev(const struct fib_nh_common *nhc,
 const struct net_device *dev)
 {
 	if (nhc->nhc_dev == dev ||
 	    l3mdev_master_ifindex_rcu(nhc->nhc_dev) == dev->ifindex)
 		return true;

 	return false;
 }

 /* 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_device *dev, __be32 local);
 int fib_sync_up(struct net_device *dev, unsigned char nh_flags);
 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu);
 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig);

 /* Fields used for sysctl_fib_multipath_hash_fields.
  * Common to IPv4 and IPv6.
  *
  * Add new fields at the end. This is user API.
  */
 #define FIB_MULTIPATH_HASH_FIELD_SRC_IP			BIT(0)
 #define FIB_MULTIPATH_HASH_FIELD_DST_IP			BIT(1)
 #define FIB_MULTIPATH_HASH_FIELD_IP_PROTO		BIT(2)
 #define FIB_MULTIPATH_HASH_FIELD_FLOWLABEL		BIT(3)
 #define FIB_MULTIPATH_HASH_FIELD_SRC_PORT		BIT(4)
 #define FIB_MULTIPATH_HASH_FIELD_DST_PORT		BIT(5)
 #define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP		BIT(6)
 #define FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP		BIT(7)
 #define FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO		BIT(8)
 #define FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL	BIT(9)
 #define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT		BIT(10)
 #define FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT		BIT(11)

 #define FIB_MULTIPATH_HASH_FIELD_OUTER_MASK		\
 	(FIB_MULTIPATH_HASH_FIELD_SRC_IP |		\
 	 FIB_MULTIPATH_HASH_FIELD_DST_IP |		\
 	 FIB_MULTIPATH_HASH_FIELD_IP_PROTO |		\
 	 FIB_MULTIPATH_HASH_FIELD_FLOWLABEL |		\
 	 FIB_MULTIPATH_HASH_FIELD_SRC_PORT |		\
 	 FIB_MULTIPATH_HASH_FIELD_DST_PORT)

 #define FIB_MULTIPATH_HASH_FIELD_INNER_MASK		\
 	(FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP |	\
 	 FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP |	\
 	 FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO |	\
 	 FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL |	\
 	 FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT |	\
 	 FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)

 #define FIB_MULTIPATH_HASH_FIELD_ALL_MASK		\
 	(FIB_MULTIPATH_HASH_FIELD_OUTER_MASK |		\
 	 FIB_MULTIPATH_HASH_FIELD_INNER_MASK)

 #define FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK		\
 	(FIB_MULTIPATH_HASH_FIELD_SRC_IP |		\
 	 FIB_MULTIPATH_HASH_FIELD_DST_IP |		\
 	 FIB_MULTIPATH_HASH_FIELD_IP_PROTO)

 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
 		       const struct sk_buff *skb, struct flow_keys *flkeys);

 static void
 fib_multipath_hash_construct_key(siphash_key_t *key, u32 mp_seed)
 {
 	u64 mp_seed_64 = mp_seed;

 	key->key[0] = (mp_seed_64 << 32) | mp_seed_64;
 	key->key[1] = key->key[0];
 }

 static inline u32 fib_multipath_hash_from_keys(const struct net *net,
 					       struct flow_keys *keys)
 {
 	siphash_aligned_key_t hash_key;
 	u32 mp_seed;

 	mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
 	fib_multipath_hash_construct_key(&hash_key, mp_seed);

 	return flow_hash_from_keys_seed(keys, &hash_key);
 }
 #else
 static inline u32 fib_multipath_hash_from_keys(const struct net *net,
 					       struct flow_keys *keys)
 {
 	return flow_hash_from_keys(keys);
 }
 #endif

 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
 		 struct netlink_ext_ack *extack);
 void fib_select_multipath(struct fib_result *res, int hash);
 void fib_select_path(struct net *net, struct fib_result *res,
 		     struct flowi4 *fl4, const struct sk_buff *skb);

 int fib_nh_init(struct net *net, struct fib_nh *fib_nh,
 		struct fib_config *cfg, int nh_weight,
 		struct netlink_ext_ack *extack);
 void fib_nh_release(struct net *net, struct fib_nh *fib_nh);
 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 		       struct nlattr *fc_encap, u16 fc_encap_type,
 		       void *cfg, gfp_t gfp_flags,
 		       struct netlink_ext_ack *extack);
 void fib_nh_common_release(struct fib_nh_common *nhc);

 /* Exported by fib_trie.c */
 void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri);
 void fib_trie_init(void);
 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias);
 bool fib_lookup_good_nhc(const struct fib_nh_common *nhc, int fib_flags,
 			 const struct flowi4 *flp);

 static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
 {
 #ifdef CONFIG_IP_ROUTE_CLASSID
 	struct fib_nh_common *nhc = res->nhc;
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	u32 rtag;
 #endif
 	if (nhc->nhc_family == AF_INET) {
 		struct fib_nh *nh;

 		nh = container_of(nhc, struct fib_nh, nh_common);
 		*itag = nh->nh_tclassid << 16;
 	} else {
 		*itag = 0;
 	}

 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	rtag = res->tclassid;
 	if (*itag == 0)
 		*itag = (rtag<<16);
 	*itag |= (rtag>>16);
 #endif
 #endif
 }

 void fib_flush(struct net *net);
 void free_fib_info(struct fib_info *fi);

 static inline void fib_info_hold(struct fib_info *fi)
 {
 	refcount_inc(&fi->fib_clntref);
 }

 static inline void fib_info_put(struct fib_info *fi)
 {
 	if (refcount_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

 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr);

 int ip_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
 			  struct fib_dump_filter *filter,
 			  struct netlink_callback *cb);

 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nh,
 		     u8 rt_family, unsigned char *flags, bool skip_oif);
 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nh,
 		    int nh_weight, u8 rt_family, u32 nh_tclassid);
 #endif  /* _NET_FIB_H */
	/* SPDX-License-Identifier: GPL-2.0-or-later */
	/*
	* 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>
	*/

	#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_notifier.h>
	#include <net/fib_rules.h>
	#include <net/inet_dscp.h>
	#include <net/inetpeer.h>
	#include <linux/percpu.h>
	#include <linux/notifier.h>
	#include <linux/refcount.h>
	#include <linux/ip.h>
	#include <linux/in_route.h>

	struct fib_config {
	u8 fc_dst_len;
	dscp_t fc_dscp;
	u8 fc_protocol;
	u8 fc_scope;
	u8 fc_type;
	u8 fc_gw_family;
	/* 2 bytes unused */
	u32 fc_table;
	__be32 fc_dst;
	union {
	__be32 fc_gw4;
	struct in6_addr fc_gw6;
	};
	int fc_oif;
	u32 fc_flags;
	u32 fc_priority;
	__be32 fc_prefsrc;
	u32 fc_nh_id;
	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;
	bool fnhe_mtu_locked;
	__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_common {
	struct net_device *nhc_dev;
	netdevice_tracker nhc_dev_tracker;
	int nhc_oif;
	unsigned char nhc_scope;
	u8 nhc_family;
	u8 nhc_gw_family;
	unsigned char nhc_flags;
	struct lwtunnel_state *nhc_lwtstate;

	union {
	__be32 ipv4;
	struct in6_addr ipv6;
	} nhc_gw;

	int nhc_weight;
	atomic_t nhc_upper_bound;

	/* v4 specific, but allows fib6_nh with v4 routes */
	struct rtable __rcu * __percpu *nhc_pcpu_rth_output;
	struct rtable __rcu *nhc_rth_input;
	struct fnhe_hash_bucket __rcu *nhc_exceptions;
	};

	struct fib_nh {
	struct fib_nh_common nh_common;
	struct hlist_node nh_hash;
	struct fib_info *nh_parent;
	#ifdef CONFIG_IP_ROUTE_CLASSID
	__u32 nh_tclassid;
	#endif
	__be32 nh_saddr;
	int nh_saddr_genid;
	#define fib_nh_family nh_common.nhc_family
	#define fib_nh_dev nh_common.nhc_dev
	#define fib_nh_dev_tracker nh_common.nhc_dev_tracker
	#define fib_nh_oif nh_common.nhc_oif
	#define fib_nh_flags nh_common.nhc_flags
	#define fib_nh_lws nh_common.nhc_lwtstate
	#define fib_nh_scope nh_common.nhc_scope
	#define fib_nh_gw_family nh_common.nhc_gw_family
	#define fib_nh_gw4 nh_common.nhc_gw.ipv4
	#define fib_nh_gw6 nh_common.nhc_gw.ipv6
	#define fib_nh_weight nh_common.nhc_weight
	#define fib_nh_upper_bound nh_common.nhc_upper_bound
	};

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

	struct nexthop;

	struct fib_info {
	struct hlist_node fib_hash;
	struct hlist_node fib_lhash;
	struct list_head nh_list;
	struct net *fib_net;
	refcount_t fib_treeref;
	refcount_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_tb_id;
	u32 fib_priority;
	struct dst_metrics *fib_metrics;
	#define fib_mtu fib_metrics->metrics[RTAX_MTU-1]
	#define fib_window fib_metrics->metrics[RTAX_WINDOW-1]
	#define fib_rtt fib_metrics->metrics[RTAX_RTT-1]
	#define fib_advmss fib_metrics->metrics[RTAX_ADVMSS-1]
	int fib_nhs;
	bool fib_nh_is_v6;
	bool nh_updated;
	bool pfsrc_removed;
	struct nexthop *nh;
	struct rcu_head rcu;
	struct fib_nh fib_nh[] __counted_by(fib_nhs);
	};


	#ifdef CONFIG_IP_MULTIPLE_TABLES
	struct fib_rule;
	#endif

	struct fib_table;
	struct fib_result {
	__be32 prefix;
	unsigned char prefixlen;
	unsigned char nh_sel;
	unsigned char type;
	unsigned char scope;
	u32 tclassid;
	dscp_t dscp;
	struct fib_nh_common *nhc;
	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_MULTIPLE_TABLES
	#define FIB_TABLE_HASHSZ 256
	#else
	#define FIB_TABLE_HASHSZ 2
	#endif

	__be32 fib_info_update_nhc_saddr(struct net net, struct fib_nh_common nhc,
	unsigned char scope);
	__be32 fib_result_prefsrc(struct net net, struct fib_result res);

	#define FIB_RES_NHC(res) ((res).nhc)
	#define FIB_RES_DEV(res) (FIB_RES_NHC(res)->nhc_dev)
	#define FIB_RES_OIF(res) (FIB_RES_NHC(res)->nhc_oif)

	struct fib_rt_info {
	struct fib_info *fi;
	u32 tb_id;
	__be32 dst;
	int dst_len;
	dscp_t dscp;
	u8 type;
	u8 offload:1,
	trap:1,
	offload_failed:1,
	unused:5;
	};

	struct fib_entry_notifier_info {
	struct fib_notifier_info info; /* must be first */
	u32 dst;
	int dst_len;
	struct fib_info *fi;
	dscp_t dscp;
	u8 type;
	u32 tb_id;
	};

	struct fib_nh_notifier_info {
	struct fib_notifier_info info; /* must be first */
	struct fib_nh *fib_nh;
	};

	int call_fib4_notifier(struct notifier_block *nb,
	enum fib_event_type event_type,
	struct fib_notifier_info *info);
	int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
	struct fib_notifier_info *info);

	int __net_init fib4_notifier_init(struct net *net);
	void __net_exit fib4_notifier_exit(struct net *net);

	void fib_info_notify_update(struct net net, struct nl_info info);
	int fib_notify(struct net net, struct notifier_block nb,
	struct netlink_ext_ack *extack);

	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[];
	};

	struct fib_dump_filter {
	u32 table_id;
	/* filter_set is an optimization that an entry is set */
	bool filter_set;
	bool dump_routes;
	bool dump_exceptions;
	bool rtnl_held;
	unsigned char protocol;
	unsigned char rt_type;
	unsigned int flags;
	struct net_device *dev;
	};

	int fib_table_lookup(struct fib_table tb, const struct flowi4 flp,
	struct fib_result *res, int fib_flags);
	int fib_table_insert(struct net , struct fib_table , struct fib_config *,
	struct netlink_ext_ack *extack);
	int fib_table_delete(struct net , struct fib_table , struct fib_config *,
	struct netlink_ext_ack *extack);
	int fib_table_dump(struct fib_table table, struct sk_buff skb,
	struct netlink_callback cb, struct fib_dump_filter filter);
	int fib_table_flush(struct net net, struct fib_table table, bool flush_all);
	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;
	}

	static inline bool fib4_has_custom_rules(const struct net *net)
	{
	return false;
	}

	static inline bool fib4_rule_default(const struct fib_rule *rule)
	{
	return true;
	}

	static inline int fib4_rules_dump(struct net net, struct notifier_block nb,
	struct netlink_ext_ack *extack)
	{
	return 0;
	}

	static inline unsigned int fib4_rules_seq_read(struct net *net)
	{
	return 0;
	}

	static inline bool fib4_rules_early_flow_dissect(struct net *net,
	struct sk_buff *skb,
	struct flowi4 *fl4,
	struct flow_keys *flkeys)
	{
	return false;
	}
	#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;
	}

	static inline bool fib4_has_custom_rules(const struct net *net)
	{
	return net->ipv4.fib_has_custom_rules;
	}

	bool fib4_rule_default(const struct fib_rule *rule);
	int fib4_rules_dump(struct net net, struct notifier_block nb,
	struct netlink_ext_ack *extack);
	unsigned int fib4_rules_seq_read(struct net *net);

	static inline bool fib4_rules_early_flow_dissect(struct net *net,
	struct sk_buff *skb,
	struct flowi4 *fl4,
	struct flow_keys *flkeys)
	{
	unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;

	if (!net->ipv4.fib_rules_require_fldissect)
	return false;

	memset(flkeys, 0, sizeof(*flkeys));
	__skb_flow_dissect(net, skb, &flow_keys_dissector,
	flkeys, NULL, 0, 0, 0, flag);

	fl4->fl4_sport = flkeys->ports.src;
	fl4->fl4_dport = flkeys->ports.dst;
	fl4->flowi4_proto = flkeys->basic.ip_proto;

	return true;
	}

	#endif /* CONFIG_IP_MULTIPLE_TABLES */

	static inline bool fib_dscp_masked_match(dscp_t dscp, const struct flowi4 *fl4)
	{
	return dscp == inet_dsfield_to_dscp(RT_TOS(fl4->flowi4_tos));
	}

	/* Exported by fib_frontend.c */
	extern const struct nla_policy rtm_ipv4_policy[];
	void ip_fib_init(void);
	int fib_gw_from_via(struct fib_config cfg, struct nlattr nla,
	struct netlink_ext_ack *extack);
	__be32 fib_compute_spec_dst(struct sk_buff *skb);
	bool fib_info_nh_uses_dev(struct fib_info fi, const struct net_device dev);
	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);
	#ifdef CONFIG_IP_ROUTE_CLASSID
	static inline int fib_num_tclassid_users(struct net *net)
	{
	return atomic_read(&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);

	static inline bool nhc_l3mdev_matches_dev(const struct fib_nh_common *nhc,
	const struct net_device *dev)
	{
	if (nhc->nhc_dev == dev \|\|
	l3mdev_master_ifindex_rcu(nhc->nhc_dev) == dev->ifindex)
	return true;

	return false;
	}

	/* 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_device *dev, __be32 local);
	int fib_sync_up(struct net_device *dev, unsigned char nh_flags);
	void fib_sync_mtu(struct net_device *dev, u32 orig_mtu);
	void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig);

	/* Fields used for sysctl_fib_multipath_hash_fields.
	* Common to IPv4 and IPv6.
	*
	* Add new fields at the end. This is user API.
	*/
	#define FIB_MULTIPATH_HASH_FIELD_SRC_IP BIT(0)
	#define FIB_MULTIPATH_HASH_FIELD_DST_IP BIT(1)
	#define FIB_MULTIPATH_HASH_FIELD_IP_PROTO BIT(2)
	#define FIB_MULTIPATH_HASH_FIELD_FLOWLABEL BIT(3)
	#define FIB_MULTIPATH_HASH_FIELD_SRC_PORT BIT(4)
	#define FIB_MULTIPATH_HASH_FIELD_DST_PORT BIT(5)
	#define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP BIT(6)
	#define FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP BIT(7)
	#define FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO BIT(8)
	#define FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL BIT(9)
	#define FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT BIT(10)
	#define FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT BIT(11)

	#define FIB_MULTIPATH_HASH_FIELD_OUTER_MASK \
	(FIB_MULTIPATH_HASH_FIELD_SRC_IP \| \
	FIB_MULTIPATH_HASH_FIELD_DST_IP \| \
	FIB_MULTIPATH_HASH_FIELD_IP_PROTO \| \
	FIB_MULTIPATH_HASH_FIELD_FLOWLABEL \| \
	FIB_MULTIPATH_HASH_FIELD_SRC_PORT \| \
	FIB_MULTIPATH_HASH_FIELD_DST_PORT)

	#define FIB_MULTIPATH_HASH_FIELD_INNER_MASK \
	(FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP \| \
	FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP \| \
	FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO \| \
	FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL \| \
	FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT \| \
	FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)

	#define FIB_MULTIPATH_HASH_FIELD_ALL_MASK \
	(FIB_MULTIPATH_HASH_FIELD_OUTER_MASK \| \
	FIB_MULTIPATH_HASH_FIELD_INNER_MASK)

	#define FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK \
	(FIB_MULTIPATH_HASH_FIELD_SRC_IP \| \
	FIB_MULTIPATH_HASH_FIELD_DST_IP \| \
	FIB_MULTIPATH_HASH_FIELD_IP_PROTO)

	#ifdef CONFIG_IP_ROUTE_MULTIPATH
	int fib_multipath_hash(const struct net net, const struct flowi4 fl4,
	const struct sk_buff skb, struct flow_keys flkeys);

	static void
	fib_multipath_hash_construct_key(siphash_key_t *key, u32 mp_seed)
	{
	u64 mp_seed_64 = mp_seed;

	key->key[0] = (mp_seed_64 << 32) \| mp_seed_64;
	key->key[1] = key->key[0];
	}

	static inline u32 fib_multipath_hash_from_keys(const struct net *net,
	struct flow_keys *keys)
	{
	siphash_aligned_key_t hash_key;
	u32 mp_seed;

	mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
	fib_multipath_hash_construct_key(&hash_key, mp_seed);

	return flow_hash_from_keys_seed(keys, &hash_key);
	}
	#else
	static inline u32 fib_multipath_hash_from_keys(const struct net *net,
	struct flow_keys *keys)
	{
	return flow_hash_from_keys(keys);
	}
	#endif

	int fib_check_nh(struct net net, struct fib_nh nh, u32 table, u8 scope,
	struct netlink_ext_ack *extack);
	void fib_select_multipath(struct fib_result *res, int hash);
	void fib_select_path(struct net net, struct fib_result res,
	struct flowi4 fl4, const struct sk_buff skb);

	int fib_nh_init(struct net net, struct fib_nh fib_nh,
	struct fib_config *cfg, int nh_weight,
	struct netlink_ext_ack *extack);
	void fib_nh_release(struct net net, struct fib_nh fib_nh);
	int fib_nh_common_init(struct net net, struct fib_nh_common nhc,
	struct nlattr *fc_encap, u16 fc_encap_type,
	void *cfg, gfp_t gfp_flags,
	struct netlink_ext_ack *extack);
	void fib_nh_common_release(struct fib_nh_common *nhc);

	/* Exported by fib_trie.c */
	void fib_alias_hw_flags_set(struct net net, const struct fib_rt_info fri);
	void fib_trie_init(void);
	struct fib_table fib_trie_table(u32 id, struct fib_table alias);
	bool fib_lookup_good_nhc(const struct fib_nh_common *nhc, int fib_flags,
	const struct flowi4 *flp);

	static inline void fib_combine_itag(u32 itag, const struct fib_result res)
	{
	#ifdef CONFIG_IP_ROUTE_CLASSID
	struct fib_nh_common *nhc = res->nhc;
	#ifdef CONFIG_IP_MULTIPLE_TABLES
	u32 rtag;
	#endif
	if (nhc->nhc_family == AF_INET) {
	struct fib_nh *nh;

	nh = container_of(nhc, struct fib_nh, nh_common);
	*itag = nh->nh_tclassid << 16;
	} else {
	*itag = 0;
	}

	#ifdef CONFIG_IP_MULTIPLE_TABLES
	rtag = res->tclassid;
	if (*itag == 0)
	*itag = (rtag<<16);
	*itag \|= (rtag>>16);
	#endif
	#endif
	}

	void fib_flush(struct net *net);
	void free_fib_info(struct fib_info *fi);

	static inline void fib_info_hold(struct fib_info *fi)
	{
	refcount_inc(&fi->fib_clntref);
	}

	static inline void fib_info_put(struct fib_info *fi)
	{
	if (refcount_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

	u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr);

	int ip_valid_fib_dump_req(struct net net, const struct nlmsghdr nlh,
	struct fib_dump_filter *filter,
	struct netlink_callback *cb);

	int fib_nexthop_info(struct sk_buff skb, const struct fib_nh_common nh,
	u8 rt_family, unsigned char *flags, bool skip_oif);
	int fib_add_nexthop(struct sk_buff skb, const struct fib_nh_common nh,
	int nh_weight, u8 rt_family, u32 nh_tclassid);
	#endif /* _NET_FIB_H */