/*------------------------------------------------------------------------
* 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);
}
/*------------------------------------------------------------------------
* arpalloc - allocate an entry in the ARP table
* N.B. Assumes interrupts DISABLED
*------------------------------------------------------------------------
*/
struct arpentry *arpalloc()
{
static int aenext = 0;
struct arpentry *pae;
int i;
for (i=0; i<ARP_TSIZE; ++i) {
if (arptable[aenext].ae_state == AS_FREE)
break;
aenext = (aenext + 1) % ARP_TSIZE;
}
pae = & arptable[aenext];
aenext = (aenext + 1) % ARP_TSIZE;
if (pae->ae_state == AS_PENDING && pae->ae_queue >= 0)
arpdq(pae);
pae->ae_state = AS_PENDING;
return pae;
}
