#ifndef _NET_DST_OPS_H
  #define _NET_DST_OPS_H
  #include <linux/types.h>

  #include <linux/percpu_counter.h>

  #include <linux/cache.h>

  
  struct dst_entry;
  struct kmem_cachep;
  struct net_device;
  struct sk_buff;
  
  struct dst_ops {
  	unsigned short		family;
  	__be16			protocol;
  	unsigned		gc_thresh;
  
  	int			(*gc)(struct dst_ops *ops);
  	struct dst_entry *	(*check)(struct dst_entry *, __u32 cookie);

  	unsigned int		(*default_advmss)(const struct dst_entry *);

  	unsigned int		(*mtu)(const struct dst_entry *);

  	u32 *			(*cow_metrics)(struct dst_entry *, unsigned long);

  	void			(*destroy)(struct dst_entry *);
  	void			(*ifdown)(struct dst_entry *,
  					  struct net_device *dev, int how);
  	struct dst_entry *	(*negative_advice)(struct dst_entry *);
  	void			(*link_failure)(struct sk_buff *);
  	void			(*update_pmtu)(struct dst_entry *dst, u32 mtu);
  	int			(*local_out)(struct sk_buff *skb);

  	struct neighbour *	(*neigh_lookup)(const struct dst_entry *dst, const void *daddr);

  	struct kmem_cache	*kmem_cachep;

  
  	struct percpu_counter	pcpuc_entries ____cacheline_aligned_in_smp;

  };

  
  static inline int dst_entries_get_fast(struct dst_ops *dst)
  {
  	return percpu_counter_read_positive(&dst->pcpuc_entries);
  }
  
  static inline int dst_entries_get_slow(struct dst_ops *dst)
  {
  	int res;
  
  	local_bh_disable();
  	res = percpu_counter_sum_positive(&dst->pcpuc_entries);
  	local_bh_enable();
  	return res;
  }
  
  static inline void dst_entries_add(struct dst_ops *dst, int val)
  {
  	local_bh_disable();
  	percpu_counter_add(&dst->pcpuc_entries, val);
  	local_bh_enable();
  }
  
  static inline int dst_entries_init(struct dst_ops *dst)
  {
  	return percpu_counter_init(&dst->pcpuc_entries, 0);
  }
  
  static inline void dst_entries_destroy(struct dst_ops *dst)
  {
  	percpu_counter_destroy(&dst->pcpuc_entries);
  }

  #endif