218 lines
6.0 KiB
C
218 lines
6.0 KiB
C
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/*
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* Copyright (c) 1992 Regents of the University of California.
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* All rights reserved.
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*
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* This software was developed by the Computer Systems Engineering group
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* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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* contributed to Berkeley.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Lawrence Berkeley Laboratory and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL)
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* $Id: arp.c,v 1.1 1994/05/08 16:11:16 brezak Exp $
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <netinet/in_systm.h>
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#include <errno.h>
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#include <string.h>
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#include "stand.h"
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#include "net.h"
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/* Cache stuff */
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#define ARP_NUM 8 /* need at most 3 arp entries */
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static struct arp_list {
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n_long addr;
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u_char ea[6];
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} arp_list[ARP_NUM] = {
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{ INADDR_BROADCAST, BA }
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};
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static int arp_num = 1;
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/* Local forwards */
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static int arpsend __P((struct iodesc *, void *, int));
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static int arprecv __P((struct iodesc *, void *, int));
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/* Broadcast an ARP packet, asking who has addr on interface d */
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u_char *
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arpwhohas(d, addr)
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register struct iodesc *d;
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n_long addr;
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{
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register int i;
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register struct ether_arp *ah;
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register struct arp_list *al;
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struct {
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u_char header[ETHER_SIZE];
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struct ether_arp warp;
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} wbuf;
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union {
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u_char buffer[RECV_SIZE];
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struct {
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u_char header[ETHER_SIZE];
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struct ether_arp rarp;
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} ru;
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} rbuf;
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#ifdef ARP_DEBUG
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if (debug)
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printf("arpwhohas: called for %s\n", intoa(addr));
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#endif
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/* Try for cached answer first */
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for (i = 0, al = arp_list; i < arp_num; ++i, ++al)
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if (addr == al->addr)
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return (al->ea);
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/* Don't overflow cache */
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if (arp_num > ARP_NUM - 1)
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panic("arpwhohas: overflowed arp_list!");
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#ifdef ARP_DEBUG
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if (debug)
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printf("arpwhohas: not cached\n");
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#endif
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ah = &wbuf.warp;
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bzero(ah, sizeof(*ah));
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ah->arp_hrd = htons(ARPHRD_ETHER);
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ah->arp_pro = htons(ETHERTYPE_IP);
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ah->arp_hln = sizeof(ah->arp_sha); /* hardware address length */
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ah->arp_pln = sizeof(ah->arp_spa); /* protocol address length */
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ah->arp_op = htons(ARPOP_REQUEST);
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MACPY(d->myea, ah->arp_sha);
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bcopy(&d->myip, ah->arp_spa, sizeof(ah->arp_spa));
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bcopy(&addr, ah->arp_tpa, sizeof(ah->arp_tpa));
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/* Store ip address in cache */
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al->addr = addr;
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(void)sendrecv(d, arpsend, ah, sizeof(*ah), arprecv,
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((u_char *)&rbuf.ru.rarp) - ETHER_SIZE,
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ETHER_SIZE + sizeof(rbuf.ru.rarp));
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/* Store ethernet address in cache */
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MACPY(rbuf.ru.rarp.arp_sha, al->ea);
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++arp_num;
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#ifdef ARP_DEBUG
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if (debug)
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printf("arpwhohas: cacheing %s --> %s\n", intoa(addr), ether_sprintf(al->ea));
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#endif
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return (al->ea);
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}
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static int
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arpsend(d, pkt, len)
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register struct iodesc *d;
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register void *pkt;
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register int len;
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{
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#ifdef ARP_DEBUG
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if (debug)
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printf("arpsend: called\n");
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#endif
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return (sendether(d, pkt, len, bcea, ETHERTYPE_ARP));
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}
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/* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */
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static int
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arprecv(d, pkt, len)
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register struct iodesc *d;
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register void *pkt;
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register int len;
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{
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register struct ether_header *eh;
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register struct ether_arp *ah;
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#ifdef ARP_DEBUG
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if (debug)
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printf("arprecv: called\n");
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#endif
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if (len < sizeof(*eh) + sizeof(*ah)) {
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errno = 0;
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return (-1);
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}
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eh = (struct ether_header *)pkt;
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/* Must be to us */
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if (bcmp(d->myea, eh->ether_dhost, 6) != 0 &&
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bcmp(bcea, eh->ether_dhost, 6) != 0) {
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#ifdef ARP_DEBUG
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if (debug)
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printf("arprecv: not ours %s\n", ether_sprintf(eh->ether_dhost));
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#endif
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errno = 0;
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return (-1);
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}
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if (ntohs(eh->ether_type) != ETHERTYPE_ARP) {
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#ifdef ARP_DEBUG
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if (debug)
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printf("arprecv: not arp %d\n", ntohs(eh->ether_type));
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#endif
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errno = 0;
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return (-1);
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}
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ah = (struct ether_arp *)(eh + 1);
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HTONS(ah->arp_hrd);
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HTONS(ah->arp_pro);
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HTONS(ah->arp_op);
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if (ah->arp_hrd != ARPHRD_ETHER || ah->arp_pro != ETHERTYPE_IP ||
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ah->arp_hln != sizeof(ah->arp_sha) ||
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ah->arp_pln != sizeof(ah->arp_spa) || ah->arp_op != ARPOP_REPLY) {
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#ifdef ARP_DEBUG
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if (debug)
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printf("arprecv: not valid reply\n");
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#endif
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errno = 0;
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return (-1);
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}
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if (bcmp(&arp_list[arp_num].addr, ah->arp_spa, sizeof(long)) != 0 ||
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bcmp(&d->myip, ah->arp_tpa, sizeof(d->myip)) != 0) {
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#ifdef ARP_DEBUG
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if (debug)
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printf("arprecv: already cached??\n");
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#endif
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errno = 0;
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return (-1);
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}
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return (0);
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}
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