1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* linux/net/inet/arp.h */
3 #ifndef _ARP_H
4 #define _ARP_H
5 
6 #include <linux/if_arp.h>
7 #include <linux/hash.h>
8 #include <net/neighbour.h>
9 
10 
11 extern struct neigh_table arp_tbl;
12 
arp_hashfn(const void * pkey,const struct net_device * dev,u32 * hash_rnd)13 static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd)
14 {
15 	u32 key = *(const u32 *)pkey;
16 	u32 val = key ^ hash32_ptr(dev);
17 
18 	return val * hash_rnd[0];
19 }
20 
21 #ifdef CONFIG_INET
__ipv4_neigh_lookup_noref(struct net_device * dev,u32 key)22 static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
23 {
24 	if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
25 		key = INADDR_ANY;
26 
27 	return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev);
28 }
29 #else
30 static inline
__ipv4_neigh_lookup_noref(struct net_device * dev,u32 key)31 struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
32 {
33 	return NULL;
34 }
35 #endif
36 
__ipv4_neigh_lookup(struct net_device * dev,u32 key)37 static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
38 {
39 	struct neighbour *n;
40 
41 	rcu_read_lock_bh();
42 	n = __ipv4_neigh_lookup_noref(dev, key);
43 	if (n && !refcount_inc_not_zero(&n->refcnt))
44 		n = NULL;
45 	rcu_read_unlock_bh();
46 
47 	return n;
48 }
49 
__ipv4_confirm_neigh(struct net_device * dev,u32 key)50 static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key)
51 {
52 	struct neighbour *n;
53 
54 	rcu_read_lock_bh();
55 	n = __ipv4_neigh_lookup_noref(dev, key);
56 	if (n) {
57 		unsigned long now = jiffies;
58 
59 		/* avoid dirtying neighbour */
60 		if (READ_ONCE(n->confirmed) != now)
61 			WRITE_ONCE(n->confirmed, now);
62 	}
63 	rcu_read_unlock_bh();
64 }
65 
66 void arp_init(void);
67 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
68 void arp_send(int type, int ptype, __be32 dest_ip,
69 	      struct net_device *dev, __be32 src_ip,
70 	      const unsigned char *dest_hw,
71 	      const unsigned char *src_hw, const unsigned char *th);
72 int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);
73 void arp_ifdown(struct net_device *dev);
74 
75 struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
76 			   struct net_device *dev, __be32 src_ip,
77 			   const unsigned char *dest_hw,
78 			   const unsigned char *src_hw,
79 			   const unsigned char *target_hw);
80 void arp_xmit(struct sk_buff *skb);
81 
82 #endif	/* _ARP_H */
83