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/* -*- c++ -*- */
/*
* Copyright 2009-2011,2014 Ettus Research LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "arp_cache.h"
#include <stddef.h>
typedef struct {
struct ip_addr ip;
eth_mac_addr_t mac;
} arp_cache_t;
#define NENTRIES 8 // power-of-2
static size_t nentries;
static size_t victim;
static arp_cache_t cache[NENTRIES];
void
arp_cache_init(void)
{
nentries = 0;
victim = 0;
}
// returns non-negative index if found, else -1
static int
arp_cache_lookup(const struct ip_addr *ip)
{
int i;
for (i = 0; i < nentries; i++)
if (cache[i].ip.addr == ip->addr)
return i;
return -1;
}
static int
arp_cache_alloc(void)
{
if (nentries < NENTRIES)
return nentries++;
int i = victim;
victim = (victim + 1) % NENTRIES;
return i;
}
void
arp_cache_update(const struct ip_addr *ip,
const eth_mac_addr_t *mac)
{
int i = arp_cache_lookup(ip);
if (i < 0){
i = arp_cache_alloc();
cache[i].ip = *ip;
cache[i].mac = *mac;
}
else {
cache[i].mac = *mac;
}
}
bool
arp_cache_lookup_mac(const struct ip_addr *ip,
eth_mac_addr_t *mac)
{
int i = arp_cache_lookup(ip);
if (i < 0)
return false;
*mac = cache[i].mac;
return true;
}
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