246 lines
6.6 KiB
C
246 lines
6.6 KiB
C
/*
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* Copyright (c) 1994, 1995, 1996, 1997, 1998
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* The Regents of the University of California. All rights reserved.
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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 Computer Systems
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* Engineering Group at Lawrence Berkeley Laboratory.
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* 4. Neither the name of the University nor of the Laboratory may be used
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* to endorse or promote products derived from this software without
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* 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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#ifndef lint
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static const char rcsid[] =
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"@(#) $Header: /tcpdump/master/libpcap/inet.c,v 1.24.2.1 2000/01/14 18:00:50 mcr Exp $ (LBL)";
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#endif
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#ifdef HAVE_SYS_SOCKIO_H
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#include <sys/sockio.h>
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#endif
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#include <sys/time.h> /* concession to AIX */
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#if __STDC__
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struct mbuf;
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struct rtentry;
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#endif
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#include <net/if.h>
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#include <netinet/in.h>
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#include <ctype.h>
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#include <errno.h>
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#include <memory.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "pcap-int.h"
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#include "gnuc.h"
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#ifdef HAVE_OS_PROTO_H
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#include "os-proto.h"
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#endif
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/* Not all systems have IFF_LOOPBACK */
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#ifdef IFF_LOOPBACK
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#define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK)
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#else
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#define ISLOOPBACK(p) ((p)->ifr_name[0] == 'l' && (p)->ifr_name[1] == 'o' && \
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(isdigit((p)->ifr_name[2]) || (p)->ifr_name[2] == '\0'))
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#endif
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/*
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* Return the name of a network interface attached to the system, or NULL
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* if none can be found. The interface must be configured up; the
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* lowest unit number is preferred; loopback is ignored.
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*/
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char *
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pcap_lookupdev(errbuf)
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register char *errbuf;
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{
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register int fd, minunit, n;
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register char *cp;
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register struct ifreq *ifrp, *ifend, *ifnext, *mp;
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struct ifconf ifc;
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char *buf;
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struct ifreq ifr;
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static char device[sizeof(ifrp->ifr_name) + 1];
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unsigned buf_size;
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (fd < 0) {
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(void)sprintf(errbuf, "socket: %s", pcap_strerror(errno));
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return (NULL);
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}
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buf_size = 8192;
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for (;;) {
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buf = malloc (buf_size);
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if (buf == NULL) {
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close (fd);
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(void)sprintf(errbuf, "out of memory");
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return (NULL);
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}
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ifc.ifc_len = buf_size;
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ifc.ifc_buf = buf;
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memset (buf, 0, buf_size);
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if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0) {
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free (buf);
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(void)sprintf(errbuf, "SIOCGIFCONF: %s",
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pcap_strerror(errno));
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(void)close(fd);
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return (NULL);
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}
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if (ifc.ifc_len < buf_size)
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break;
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free (buf);
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buf_size *= 2;
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}
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ifrp = (struct ifreq *)buf;
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ifend = (struct ifreq *)(buf + ifc.ifc_len);
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mp = NULL;
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minunit = 666;
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for (; ifrp < ifend; ifrp = ifnext) {
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#ifdef HAVE_SOCKADDR_SA_LEN
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n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
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if (n < sizeof(*ifrp))
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ifnext = ifrp + 1;
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else
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ifnext = (struct ifreq *)((char *)ifrp + n);
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if (ifrp->ifr_addr.sa_family != AF_INET)
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continue;
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#else
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ifnext = ifrp + 1;
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#endif
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/*
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* Need a template to preserve address info that is
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* used below to locate the next entry. (Otherwise,
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* SIOCGIFFLAGS stomps over it because the requests
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* are returned in a union.)
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*/
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strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));
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if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
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if (errno == ENXIO)
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continue;
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(void)sprintf(errbuf, "SIOCGIFFLAGS: %.*s: %s",
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(int)sizeof(ifr.ifr_name), ifr.ifr_name,
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pcap_strerror(errno));
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(void)close(fd);
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free (buf);
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return (NULL);
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}
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/* Must be up and not the loopback */
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if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr))
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continue;
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for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
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continue;
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n = atoi(cp);
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if (n < minunit) {
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minunit = n;
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mp = ifrp;
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}
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}
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free(buf);
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(void)close(fd);
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if (mp == NULL) {
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(void)strcpy(errbuf, "no suitable device found");
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return (NULL);
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}
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(void)strncpy(device, mp->ifr_name, sizeof(device) - 1);
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device[sizeof(device) - 1] = '\0';
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return (device);
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}
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int
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pcap_lookupnet(device, netp, maskp, errbuf)
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register char *device;
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register bpf_u_int32 *netp, *maskp;
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register char *errbuf;
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{
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register int fd;
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register struct sockaddr_in *sin;
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struct ifreq ifr;
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (fd < 0) {
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(void)sprintf(errbuf, "socket: %s", pcap_strerror(errno));
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return (-1);
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}
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memset(&ifr, 0, sizeof(ifr));
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#ifdef linux
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/* XXX Work around Linux kernel bug */
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ifr.ifr_addr.sa_family = AF_INET;
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#endif
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(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
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if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
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if (errno == EADDRNOTAVAIL) {
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(void)sprintf(errbuf, "%s: no IPv4 address assigned",
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device);
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} else {
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(void)sprintf(errbuf, "SIOCGIFADDR: %s: %s",
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device, pcap_strerror(errno));
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}
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(void)close(fd);
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return (-1);
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}
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sin = (struct sockaddr_in *)&ifr.ifr_addr;
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*netp = sin->sin_addr.s_addr;
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if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
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(void)sprintf(errbuf, "SIOCGIFNETMASK: %s: %s",
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device, pcap_strerror(errno));
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(void)close(fd);
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return (-1);
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}
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(void)close(fd);
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*maskp = sin->sin_addr.s_addr;
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if (*maskp == 0) {
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if (IN_CLASSA(*netp))
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*maskp = IN_CLASSA_NET;
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else if (IN_CLASSB(*netp))
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*maskp = IN_CLASSB_NET;
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else if (IN_CLASSC(*netp))
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*maskp = IN_CLASSC_NET;
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else {
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(void)sprintf(errbuf, "inet class for 0x%x unknown",
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*netp);
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return (-1);
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}
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}
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*netp &= *maskp;
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return (0);
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}
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