/* SPDX-License-Identifier: GPL-2.0 */

  /*
   *		INETPEER - A storage for permanent information about peers
   *

   *  Authors:	Andrey V. Savochkin <saw@msu.ru>
   */
  
  #ifndef _NET_INETPEER_H
  #define _NET_INETPEER_H
  
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/jiffies.h>
  #include <linux/spinlock.h>

  #include <linux/rtnetlink.h>

  #include <net/ipv6.h>

  #include <linux/atomic.h>

  /* IPv4 address key for cache lookups */
  struct ipv4_addr_key {
  	__be32	addr;
  	int	vif;
  };

  #define INETPEER_MAXKEYSZ   (sizeof(struct in6_addr) / sizeof(u32))
  
  struct inetpeer_addr {

  	union {

  		struct ipv4_addr_key	a4;

  		struct in6_addr		a6;
  		u32			key[INETPEER_MAXKEYSZ];

  	};

  	__u16				family;

  };

  struct inet_peer {

  	struct rb_node		rb_node;

  	struct inetpeer_addr	daddr;

  
  	u32			metrics[RTAX_MAX];
  	u32			rate_tokens;	/* rate limiting for ICMP */
  	unsigned long		rate_last;

  	/*

  	 * Once inet_peer is queued for deletion (refcnt == 0), following field

  	 * is not available: rid

  	 * We can share memory with rcu_head to help keep inet_peer small.

  	 */
  	union {
  		struct {

  			atomic_t			rid;		/* Frag reception counter */

  		};
  		struct rcu_head         rcu;
  	};

  
  	/* following fields might be frequently dirtied */
  	__u32			dtime;	/* the time of last use of not referenced entries */

  	refcount_t		refcnt;

  };

  struct inet_peer_base {

  	struct rb_root		rb_root;

  	seqlock_t		lock;
  	int			total;
  };

  void inet_peer_base_init(struct inet_peer_base *);

  void inet_initpeers(void) __init;

  #define INETPEER_METRICS_NEW	(~(u32) 0)

  static inline void inetpeer_set_addr_v4(struct inetpeer_addr *iaddr, __be32 ip)
  {

  	iaddr->a4.addr = ip;

  	iaddr->a4.vif = 0;

  	iaddr->family = AF_INET;
  }
  
  static inline __be32 inetpeer_get_addr_v4(struct inetpeer_addr *iaddr)
  {

  	return iaddr->a4.addr;

  }
  
  static inline void inetpeer_set_addr_v6(struct inetpeer_addr *iaddr,
  					struct in6_addr *in6)
  {

  	iaddr->a6 = *in6;

  	iaddr->family = AF_INET6;
  }
  
  static inline struct in6_addr *inetpeer_get_addr_v6(struct inetpeer_addr *iaddr)
  {

  	return &iaddr->a6;

  }

  /* can be called with or without local BH being disabled */

  struct inet_peer *inet_getpeer(struct inet_peer_base *base,

  			       const struct inetpeer_addr *daddr,
  			       int create);

  static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,

  						__be32 v4daddr,

  						int vif, int create)

  {

  	struct inetpeer_addr daddr;

  	daddr.a4.addr = v4daddr;
  	daddr.a4.vif = vif;

  	daddr.family = AF_INET;

  	return inet_getpeer(base, &daddr, create);

  }

  static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,

  						const struct in6_addr *v6daddr,
  						int create)

  {

  	struct inetpeer_addr daddr;

  	daddr.a6 = *v6daddr;

  	daddr.family = AF_INET6;

  	return inet_getpeer(base, &daddr, create);

  }

  static inline int inetpeer_addr_cmp(const struct inetpeer_addr *a,
  				    const struct inetpeer_addr *b)
  {

  	int i, n;
  
  	if (a->family == AF_INET)
  		n = sizeof(a->a4) / sizeof(u32);
  	else
  		n = sizeof(a->a6) / sizeof(u32);

  
  	for (i = 0; i < n; i++) {

  		if (a->key[i] == b->key[i])

  			continue;

  		if (a->key[i] < b->key[i])

  			return -1;
  		return 1;
  	}
  
  	return 0;
  }

  /* can be called from BH context or outside */

  void inet_putpeer(struct inet_peer *p);
  bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);

  void inetpeer_invalidate_tree(struct inet_peer_base *);

  #endif /* _NET_INETPEER_H */