/* linux/net/inet/arp.h */#ifndef _ARP_H#define _ARP_H #include <linux/if_arp.h>#include <net/neighbour.h>  extern struct neigh_table arp_tbl; static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd){	u32 val = key ^ dev->ifindex; 	return val * hash_rnd;} static inline struct neighbour *__ipv4_neigh_lookup(struct neigh_table *tbl, struct net_device *dev, u32 key){	struct neigh_hash_table *nht;	struct neighbour *n;	u32 hash_val; 	rcu_read_lock_bh();	nht = rcu_dereference_bh(tbl->nht);	hash_val = arp_hashfn(key, dev, nht->hash_rnd) >> (32 - nht->hash_shift);	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);	     n != NULL;	     n = rcu_dereference_bh(n->next)) {		if (n->dev == dev && *(u32 *)n->primary_key == key) {			if (!atomic_inc_not_zero(&n->refcnt))				n = NULL;			break;		}	}	rcu_read_unlock_bh(); 	return n;} extern void	arp_init(void);extern int	arp_find(unsigned char *haddr, struct sk_buff *skb);extern int	arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);extern void     arp_send(int type, int ptype, __be32 dest_ip,			 struct net_device *dev, __be32 src_ip,			 const unsigned char *dest_hw,			 const unsigned char *src_hw, const unsigned char *th);extern int	arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);extern void	arp_ifdown(struct net_device *dev); extern struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,				  struct net_device *dev, __be32 src_ip,				  const unsigned char *dest_hw,				  const unsigned char *src_hw,				  const unsigned char *target_hw);extern void arp_xmit(struct sk_buff *skb);int arp_invalidate(struct net_device *dev, __be32 ip); #endif	/* _ARP_H */