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