241 lines
6.3 KiB
C
241 lines
6.3 KiB
C
/* $NetBSD: rarp.c,v 1.31 2011/05/11 16:23:40 zoltan Exp $ */
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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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* @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL)
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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_ether.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#ifdef _STANDALONE
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#include <lib/libkern/libkern.h>
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#else
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#include <string.h>
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#endif
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#include "stand.h"
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#include "net.h"
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/*
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* Ethernet Address Resolution Protocol.
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*
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* See RFC 826 for protocol description. Structure below is adapted
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* to resolving internet addresses. Field names used correspond to
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* RFC 826.
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*/
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struct ether_arp {
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struct arphdr ea_hdr; /* fixed-size header */
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u_int8_t arp_sha[ETHER_ADDR_LEN]; /* sender hardware address */
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u_int8_t arp_spa[4]; /* sender protocol address */
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u_int8_t arp_tha[ETHER_ADDR_LEN]; /* target hardware address */
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u_int8_t arp_tpa[4]; /* target protocol address */
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};
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#define arp_hrd ea_hdr.ar_hrd
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#define arp_pro ea_hdr.ar_pro
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#define arp_hln ea_hdr.ar_hln
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#define arp_pln ea_hdr.ar_pln
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#define arp_op ea_hdr.ar_op
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static ssize_t rarpsend(struct iodesc *, void *, size_t);
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static ssize_t rarprecv(struct iodesc *, void *, size_t, saseconds_t);
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/*
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* Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
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*/
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int
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rarp_getipaddress(int sock)
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{
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struct iodesc *d;
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struct ether_arp *ap;
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struct {
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u_char header[ETHERNET_HEADER_SIZE];
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struct {
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struct ether_arp arp;
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u_char pad[18]; /* 60 - sizeof(arp) */
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} data;
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} wbuf;
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struct {
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u_char header[ETHERNET_HEADER_SIZE];
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struct {
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struct ether_arp arp;
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u_char pad[24]; /* extra space */
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} data;
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} rbuf;
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarp: socket=%d\n", sock);
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#endif
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if (!(d = socktodesc(sock))) {
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printf("rarp: bad socket. %d\n", sock);
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return -1;
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}
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarp: d=%lx\n", (u_long)d);
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#endif
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(void)memset(&wbuf.data, 0, sizeof(wbuf.data));
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ap = &wbuf.data.arp;
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ap->arp_hrd = htons(ARPHRD_ETHER);
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ap->arp_pro = htons(ETHERTYPE_IP);
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ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
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ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
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ap->arp_op = htons(ARPOP_REVREQUEST);
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(void)memcpy(ap->arp_sha, d->myea, 6);
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(void)memcpy(ap->arp_tha, d->myea, 6);
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if (sendrecv(d,
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rarpsend, &wbuf.data, sizeof(wbuf.data),
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rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0)
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{
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printf("No response for RARP request\n");
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return -1;
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}
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ap = &rbuf.data.arp;
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(void)memcpy(&myip, ap->arp_tpa, sizeof(myip));
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#if 0
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/* XXX - Can NOT assume this is our root server! */
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(void)memcpy(&rootip, ap->arp_spa, sizeof(rootip));
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#endif
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/* Compute our "natural" netmask. */
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if (IN_CLASSA(myip.s_addr))
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netmask = IN_CLASSA_NET;
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else if (IN_CLASSB(myip.s_addr))
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netmask = IN_CLASSB_NET;
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else
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netmask = IN_CLASSC_NET;
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d->myip = myip;
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return 0;
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}
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/*
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* Broadcast a RARP request (i.e. who knows who I am)
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*/
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static ssize_t
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rarpsend(struct iodesc *d, void *pkt, size_t len)
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{
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarpsend: called\n");
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#endif
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return sendether(d, pkt, len, bcea, ETHERTYPE_REVARP);
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}
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/*
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* Returns 0 if this is the packet we're waiting for
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* else -1 (and errno == 0)
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*/
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static ssize_t
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rarprecv(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
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{
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ssize_t n;
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struct ether_arp *ap;
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u_int16_t etype; /* host order */
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#ifdef RARP_DEBUG
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if (debug)
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printf("rarprecv: ");
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#endif
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n = readether(d, pkt, len, tleft, &etype);
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errno = 0; /* XXX */
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if (n == -1 || (size_t)n < sizeof(struct ether_arp)) {
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#ifdef RARP_DEBUG
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if (debug)
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printf("bad len=%d\n", (int)n);
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#endif
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return -1;
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}
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if (etype != ETHERTYPE_REVARP) {
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#ifdef RARP_DEBUG
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if (debug)
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printf("bad type=0x%x\n", etype);
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#endif
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return -1;
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}
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ap = (struct ether_arp *)pkt;
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if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
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ap->arp_pro != htons(ETHERTYPE_IP) ||
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ap->arp_hln != sizeof(ap->arp_sha) ||
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ap->arp_pln != sizeof(ap->arp_spa) )
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{
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#ifdef RARP_DEBUG
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if (debug)
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printf("bad hrd/pro/hln/pln\n");
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#endif
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return -1;
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}
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if (ap->arp_op != htons(ARPOP_REVREPLY)) {
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#ifdef RARP_DEBUG
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if (debug)
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printf("bad op=0x%x\n", ntohs(ap->arp_op));
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#endif
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return -1;
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}
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/* Is the reply for our Ethernet address? */
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if (memcmp(ap->arp_tha, d->myea, 6)) {
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#ifdef RARP_DEBUG
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if (debug)
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printf("unwanted address\n");
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#endif
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return -1;
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}
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/* We have our answer. */
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#ifdef RARP_DEBUG
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if (debug)
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printf("got it\n");
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#endif
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return n;
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}
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