/* linux/net/inet/arp.h */#ifndef _ARP_H#define _ARP_H #include <linux/if_arp.h>#include <linux/hash.h>#include <net/neighbour.h>  extern struct neigh_table arp_tbl; static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd){	u32 key = *(const u32 *)pkey;	u32 val = key ^ hash32_ptr(dev); 	return val * hash_rnd[0];} static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key){	return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev);} static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key){	struct neighbour *n; 	rcu_read_lock_bh();	n = __ipv4_neigh_lookup_noref(dev, key);	if (n && !refcount_inc_not_zero(&n->refcnt))		n = NULL;	rcu_read_unlock_bh(); 	return n;} static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key){	struct neighbour *n; 	rcu_read_lock_bh();	n = __ipv4_neigh_lookup_noref(dev, key);	if (n) {		unsigned long now = jiffies; 		/* avoid dirtying neighbour */		if (n->confirmed != now)			n->confirmed = now;	}	rcu_read_unlock_bh();} void arp_init(void);int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);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);int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);void arp_ifdown(struct net_device *dev); 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);void arp_xmit(struct sk_buff *skb); #endif	/* _ARP_H */