include/net/arp.h

   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
  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
  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
  31 struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
  32 {
  33         return NULL;
  34 }
  35 #endif
  36
  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
  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 */