418 lines
12 KiB
C
418 lines
12 KiB
C
/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
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/*
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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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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <sys/param.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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struct mbuf; /* Squelch compiler warnings on some platforms for */
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struct rtentry; /* declarations in <net/if.h> */
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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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#ifdef HAVE_OS_PROTO_H
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#include "os-proto.h"
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#endif
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/*
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* This is fun.
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*
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* In older BSD systems, socket addresses were fixed-length, and
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* "sizeof (struct sockaddr)" gave the size of the structure.
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* All addresses fit within a "struct sockaddr".
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*
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* In newer BSD systems, the socket address is variable-length, and
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* there's an "sa_len" field giving the length of the structure;
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* this allows socket addresses to be longer than 2 bytes of family
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* and 14 bytes of data.
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*
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* Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
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* variant of the old BSD scheme (with "struct sockaddr_storage" rather
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* than "struct sockaddr"), and some use the new BSD scheme.
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*
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* Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
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* macro that determines the size based on the address family. Other
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* versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
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* but not in the final version).
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*
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* We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
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* SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
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* address in an entry returned by SIOCGIFCONF.
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*/
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#ifndef SA_LEN
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#ifdef HAVE_SOCKADDR_SA_LEN
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#define SA_LEN(addr) ((addr)->sa_len)
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#else /* HAVE_SOCKADDR_SA_LEN */
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#define SA_LEN(addr) (sizeof (struct sockaddr))
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#endif /* HAVE_SOCKADDR_SA_LEN */
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#endif /* SA_LEN */
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/*
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* This is also fun.
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*
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* There is no ioctl that returns the amount of space required for all
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* the data that SIOCGIFCONF could return, and if a buffer is supplied
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* that's not large enough for all the data SIOCGIFCONF could return,
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* on at least some platforms it just returns the data that'd fit with
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* no indication that there wasn't enough room for all the data, much
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* less an indication of how much more room is required.
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*
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* The only way to ensure that we got all the data is to pass a buffer
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* large enough that the amount of space in the buffer *not* filled in
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* is greater than the largest possible entry.
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*
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* We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
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* that no address is more than 255 bytes (on systems where the "sa_len"
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* field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
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* case, and addresses are unlikely to be bigger than that in any case).
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*/
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#define MAX_SA_LEN 255
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/*
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* Get a list of all interfaces that are up and that we can open.
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* Returns -1 on error, 0 otherwise.
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* The list, as returned through "alldevsp", may be null if no interfaces
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* were up and could be opened.
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*
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* This is the implementation used on platforms that have SIOCGIFCONF but
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* don't have any other mechanism for getting a list of interfaces.
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*
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* XXX - or platforms that have other, better mechanisms but for which
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* we don't yet have code to use that mechanism; I think there's a better
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* way on Linux, for example, but if that better way is "getifaddrs()",
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* we already have that.
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*/
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int
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pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
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{
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pcap_if_t *devlist = NULL;
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register int fd;
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register struct ifreq *ifrp, *ifend, *ifnext;
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int n;
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struct ifconf ifc;
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char *buf = NULL;
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unsigned buf_size;
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#if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
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char *p, *q;
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#endif
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struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
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struct sockaddr *netmask, *broadaddr, *dstaddr;
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size_t netmask_size, broadaddr_size, dstaddr_size;
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int ret = 0;
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/*
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* Create a socket from which to fetch the list of interfaces.
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*/
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (fd < 0) {
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"socket: %s", pcap_strerror(errno));
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return (-1);
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}
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/*
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* Start with an 8K buffer, and keep growing the buffer until
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* we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
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* bytes left over in the buffer or we fail to get the
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* interface list for some reason other than EINVAL (which is
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* presumed here to mean "buffer is too small").
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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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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"malloc: %s", pcap_strerror(errno));
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(void)close(fd);
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return (-1);
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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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&& errno != EINVAL) {
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"SIOCGIFCONF: %s", pcap_strerror(errno));
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(void)close(fd);
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free(buf);
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return (-1);
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}
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if (ifc.ifc_len < buf_size &&
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(buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
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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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for (; ifrp < ifend; ifrp = ifnext) {
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/*
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* XXX - what if this isn't an IPv4 address? Can
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* we still get the netmask, etc. with ioctls on
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* an IPv4 socket?
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*
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* The answer is probably platform-dependent, and
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* if the answer is "no" on more than one platform,
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* the way you work around it is probably platform-
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* dependent as well.
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*/
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n = SA_LEN(&ifrp->ifr_addr) + 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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/*
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* XXX - The 32-bit compatibility layer for Linux on IA-64
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* is slightly broken. It correctly converts the structures
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* to and from kernel land from 64 bit to 32 bit but
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* doesn't update ifc.ifc_len, leaving it larger than the
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* amount really used. This means we read off the end
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* of the buffer and encounter an interface with an
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* "empty" name. Since this is highly unlikely to ever
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* occur in a valid case we can just finish looking for
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* interfaces if we see an empty name.
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*/
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if (!(*ifrp->ifr_name))
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break;
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/*
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* Skip entries that begin with "dummy".
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* XXX - what are these? Is this Linux-specific?
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* Are there platforms on which we shouldn't do this?
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*/
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if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
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continue;
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/*
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* Get the flags for this interface.
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*/
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strncpy(ifrflags.ifr_name, ifrp->ifr_name,
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sizeof(ifrflags.ifr_name));
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if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
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if (errno == ENXIO)
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continue;
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"SIOCGIFFLAGS: %.*s: %s",
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(int)sizeof(ifrflags.ifr_name),
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ifrflags.ifr_name,
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pcap_strerror(errno));
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ret = -1;
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break;
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}
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/*
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* Get the netmask for this address on this interface.
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*/
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strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
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sizeof(ifrnetmask.ifr_name));
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memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
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sizeof(ifrnetmask.ifr_addr));
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if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
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if (errno == EADDRNOTAVAIL) {
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/*
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* Not available.
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*/
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netmask = NULL;
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netmask_size = 0;
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} else {
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"SIOCGIFNETMASK: %.*s: %s",
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(int)sizeof(ifrnetmask.ifr_name),
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ifrnetmask.ifr_name,
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pcap_strerror(errno));
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ret = -1;
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break;
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}
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} else {
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netmask = &ifrnetmask.ifr_addr;
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netmask_size = SA_LEN(netmask);
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}
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/*
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* Get the broadcast address for this address on this
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* interface (if any).
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*/
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if (ifrflags.ifr_flags & IFF_BROADCAST) {
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strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
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sizeof(ifrbroadaddr.ifr_name));
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memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
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sizeof(ifrbroadaddr.ifr_addr));
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if (ioctl(fd, SIOCGIFBRDADDR,
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(char *)&ifrbroadaddr) < 0) {
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if (errno == EADDRNOTAVAIL) {
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/*
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* Not available.
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*/
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broadaddr = NULL;
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broadaddr_size = 0;
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} else {
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"SIOCGIFBRDADDR: %.*s: %s",
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(int)sizeof(ifrbroadaddr.ifr_name),
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ifrbroadaddr.ifr_name,
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pcap_strerror(errno));
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ret = -1;
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break;
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}
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} else {
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broadaddr = &ifrbroadaddr.ifr_broadaddr;
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broadaddr_size = SA_LEN(broadaddr);
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}
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} else {
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/*
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* Not a broadcast interface, so no broadcast
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* address.
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*/
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broadaddr = NULL;
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broadaddr_size = 0;
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}
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/*
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* Get the destination address for this address on this
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* interface (if any).
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*/
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if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
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strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
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sizeof(ifrdstaddr.ifr_name));
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memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
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sizeof(ifrdstaddr.ifr_addr));
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if (ioctl(fd, SIOCGIFDSTADDR,
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(char *)&ifrdstaddr) < 0) {
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if (errno == EADDRNOTAVAIL) {
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/*
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* Not available.
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*/
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dstaddr = NULL;
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dstaddr_size = 0;
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} else {
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"SIOCGIFDSTADDR: %.*s: %s",
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(int)sizeof(ifrdstaddr.ifr_name),
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ifrdstaddr.ifr_name,
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pcap_strerror(errno));
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ret = -1;
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break;
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}
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} else {
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dstaddr = &ifrdstaddr.ifr_dstaddr;
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dstaddr_size = SA_LEN(dstaddr);
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}
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} else {
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/*
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* Not a point-to-point interface, so no destination
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* address.
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*/
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dstaddr = NULL;
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dstaddr_size = 0;
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}
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#if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
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/*
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* If this entry has a colon followed by a number at
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* the end, it's a logical interface. Those are just
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* the way you assign multiple IP addresses to a real
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* interface, so an entry for a logical interface should
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* be treated like the entry for the real interface;
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* we do that by stripping off the ":" and the number.
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*/
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p = strchr(ifrp->ifr_name, ':');
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if (p != NULL) {
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/*
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* We have a ":"; is it followed by a number?
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*/
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q = p + 1;
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while (isdigit((unsigned char)*q))
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q++;
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if (*q == '\0') {
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/*
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* All digits after the ":" until the end.
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* Strip off the ":" and everything after
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* it.
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*/
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*p = '\0';
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}
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}
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#endif
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/*
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* Add information for this address to the list.
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*/
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if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
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ifrflags.ifr_flags, &ifrp->ifr_addr,
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SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
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broadaddr, broadaddr_size, dstaddr, dstaddr_size,
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errbuf) < 0) {
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ret = -1;
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break;
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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 (ret == -1) {
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/*
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* We had an error; free the list we've been constructing.
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*/
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if (devlist != NULL) {
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pcap_freealldevs(devlist);
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devlist = NULL;
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}
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}
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*alldevsp = devlist;
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return (ret);
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}
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