NetBSD/lib/libpcap/inet.c

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/* $NetBSD: inet.c,v 1.2 1995/03/06 11:38:29 mycroft Exp $ */
/*
* Copyright (c) 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Systems
* Engineering Group at Lawrence Berkeley Laboratory.
* 4. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char rcsid[] =
"@(#) Header: inet.c,v 1.4 94/06/07 01:16:50 leres Exp (LBL)";
#endif
#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef SOLARIS
#include <sys/sockio.h>
#endif
#include <net/if.h>
#include <netinet/in.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pcap.h>
/* Not all systems have IFF_LOOPBACK */
#ifdef IFF_LOOPBACK
#define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK)
#else
#define ISLOOPBACK(p) (strcmp((p)->ifr_name, "lo0") == 0)
#endif
/*
* Return the name of a network interface attached to the system, or NULL
* if none can be found. The interface must be configured up; the
* lowest unit number is preferred; loopback is ignored.
*/
char *
pcap_lookupdev(errbuf)
register char *errbuf;
{
register int fd, minunit, n;
register char *cp;
register struct ifreq *ifrp, *ifend, *ifnext, *mp;
struct ifconf ifc;
struct ifreq ibuf[16], ifr;
static char device[sizeof(ifrp->ifr_name) + 1];
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
(void)sprintf(errbuf, "socket: %s", pcap_strerror(errno));
return (NULL);
}
ifc.ifc_len = sizeof ibuf;
ifc.ifc_buf = (caddr_t)ibuf;
if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 ||
ifc.ifc_len < sizeof(struct ifreq)) {
(void)sprintf(errbuf, "SIOCGIFCONF: %s", pcap_strerror(errno));
(void)close(fd);
return (NULL);
}
ifrp = ibuf;
ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
mp = NULL;
minunit = 666;
for (; ifrp < ifend; ifrp = ifnext) {
#if BSD - 0 >= 199006
n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
if (n < sizeof(*ifrp))
ifnext = ifrp + 1;
else
ifnext = (struct ifreq *)((char *)ifrp + n);
if (ifrp->ifr_addr.sa_family != AF_INET)
continue;
#else
ifnext = ifrp + 1;
#endif
/*
* Need a template to preserve address info that is
* used below to locate the next entry. (Otherwise,
* SIOCGIFFLAGS stomps over it because the requests
* are returned in a union.)
*/
strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
(void)sprintf(errbuf, "SIOCGIFFLAGS: %s",
pcap_strerror(errno));
(void)close(fd);
return (NULL);
}
/* Must be up and not the loopback */
if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr))
continue;
for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
continue;
n = atoi(cp);
if (n < minunit) {
minunit = n;
mp = ifrp;
}
}
(void)close(fd);
if (mp == NULL) {
(void)strcpy(errbuf, "no suitable device found");
return (NULL);
}
(void)strncpy(device, mp->ifr_name, sizeof(device) - 1);
device[sizeof(device) - 1] = '\0';
return (device);
}
int
pcap_lookupnet(device, netp, maskp, errbuf)
register char *device;
register u_long *netp, *maskp;
register char *errbuf;
{
register int fd;
register struct sockaddr_in *sin;
struct ifreq ifr;
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
(void)sprintf(errbuf, "socket: %s", pcap_strerror(errno));
return (-1);
}
(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
(void)sprintf(errbuf, "SIOCGIFADDR: %s: %s",
device, pcap_strerror(errno));
(void)close(fd);
return (-1);
}
sin = (struct sockaddr_in *)&ifr.ifr_addr;
*netp = sin->sin_addr.s_addr;
if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
(void)sprintf(errbuf, "SIOCGIFNETMASK: %s: %s",
device, pcap_strerror(errno));
(void)close(fd);
return (-1);
}
(void)close(fd);
*maskp = sin->sin_addr.s_addr;
if (*maskp == 0) {
if (IN_CLASSA(*netp))
*maskp = IN_CLASSA_NET;
else if (IN_CLASSB(*netp))
*maskp = IN_CLASSB_NET;
else if (IN_CLASSC(*netp))
*maskp = IN_CLASSC_NET;
else {
(void)sprintf(errbuf, "inet class for 0x%x unknown",
*netp);
return (-1);
}
}
*netp &= *maskp;
return (0);
}