/*
* Convert an ARP request into a reply and send it.
* Notes: Re-uses buffer. Pad to length = 46.
*/
void
arp_reply(struct nbuf *nbuf)
{
struct ether_arp *arp = nbuf->nh.arph;
struct nic *d = nbuf->nic;
/* If we are not the target, ignore the request. */
if (bcmp(arp->arp_tpa, &d->ip_addr, sizeof(arp->arp_tpa))) {
return;
}
arp->arp_op = htons(ARPOP_REPLY);
/* source becomes target */
bcopy(arp->arp_sha, arp->arp_tha, sizeof(arp->arp_tha));
bcopy(arp->arp_spa, arp->arp_tpa, sizeof(arp->arp_tpa));
/* here becomes source */
bcopy(d->node_addr, arp->arp_sha, sizeof(arp->arp_sha));
bcopy(&d->ip_addr, arp->arp_spa, sizeof(arp->arp_spa));
/*
* No need to get fancy here. If the send fails, the
* requestor will just ask again.
*/
(void) arpsend(nbuf,arp->arp_tha, ETHERTYPE_ARP);
}
/*------------------------------------------------------------------------
* arptimer - Iterate through ARP cache, aging (possibly removing) entries
*------------------------------------------------------------------------
* gran - time since last iteration
*/
void
arptimer(int gran)
{
struct arpentry *pae;
STATWORD ps;
int i;
disable(ps); /* mutex */
for (i=0; i<ARP_TSIZE; ++i) {
if ((pae = &arptable[i])->ae_state == AS_FREE)
continue;
if (pae->ae_ttl == ARP_INF)
continue; /* don't time out permanent entry */
if ((pae->ae_ttl -= gran) <= 0)
if (pae->ae_state == AS_RESOLVED)
pae->ae_state = AS_FREE;
else if (++pae->ae_attempts > ARP_MAXRETRY) {
pae->ae_state = AS_FREE;
arpdq(pae);
} else {
pae->ae_ttl = ARP_RESEND;
arpsend(pae);
}
}
restore(ps);
}
