244 lines
7.3 KiB
C
244 lines
7.3 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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#ifndef lint
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static const char rcsid[] _U_ =
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"@(#) $Header: /tcpdump/master/libpcap/fad-getad.c,v 1.7.2.2 2004/03/11 23:04:52 guy Exp $ (LBL)";
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#endif
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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/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <net/if.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <ifaddrs.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). On the latter systems, we explicitly
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* check the AF_ type to determine the length; we assume that on
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* all those systems we have "struct sockaddr_storage".
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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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#ifdef HAVE_SOCKADDR_STORAGE
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static size_t
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get_sa_len(struct sockaddr *addr)
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{
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switch (addr->sa_family) {
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#ifdef AF_INET
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case AF_INET:
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return (sizeof (struct sockaddr_in));
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#endif
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#ifdef AF_INET6
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case AF_INET6:
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return (sizeof (struct sockaddr_in6));
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#endif
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default:
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return (sizeof (struct sockaddr));
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}
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}
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#define SA_LEN(addr) (get_sa_len(addr))
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#else /* HAVE_SOCKADDR_STORAGE */
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#define SA_LEN(addr) (sizeof (struct sockaddr))
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#endif /* HAVE_SOCKADDR_STORAGE */
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#endif /* HAVE_SOCKADDR_SA_LEN */
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#endif /* SA_LEN */
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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 "getifaddrs()".
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*/
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int
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pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
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{
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pcap_if_t *devlist = NULL;
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struct ifaddrs *ifap, *ifa;
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struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
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size_t addr_size, broadaddr_size, dstaddr_size;
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int ret = 0;
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/*
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* Get the list of interface addresses.
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*
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* Note: this won't return information about interfaces
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* with no addresses; are there any such interfaces
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* that would be capable of receiving packets?
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* (Interfaces incapable of receiving packets aren't
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* very interesting from libpcap's point of view.)
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*
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* LAN interfaces will probably have link-layer
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* addresses; I don't know whether all implementations
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* of "getifaddrs()" now, or in the future, will return
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* those.
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*/
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if (getifaddrs(&ifap) != 0) {
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(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
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"getifaddrs: %s", pcap_strerror(errno));
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return (-1);
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}
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for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
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/*
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* Is this interface up?
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*/
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if (!(ifa->ifa_flags & IFF_UP)) {
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/*
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* No, so don't add it to the list.
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*/
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continue;
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}
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/*
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* "ifa_addr" was apparently null on at least one
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* interface on some system.
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*
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* "ifa_broadaddr" may be non-null even on
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* non-broadcast interfaces, and was null on
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* at least one OpenBSD 3.4 system on at least
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* one interface with IFF_BROADCAST set.
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*
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* "ifa_dstaddr" was, on at least one FreeBSD 4.1
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* system, non-null on a non-point-to-point
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* interface.
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*
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* Therefore, we supply the address and netmask only
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* if "ifa_addr" is non-null (if there's no address,
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* there's obviously no netmask), and supply the
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* broadcast and destination addresses if the appropriate
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* flag is set *and* the appropriate "ifa_" entry doesn't
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* evaluate to a null pointer.
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*/
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if (ifa->ifa_addr != NULL) {
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addr = ifa->ifa_addr;
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addr_size = SA_LEN(addr);
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netmask = ifa->ifa_netmask;
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} else {
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addr = NULL;
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addr_size = 0;
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netmask = NULL;
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}
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if (ifa->ifa_flags & IFF_BROADCAST &&
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ifa->ifa_broadaddr != NULL) {
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broadaddr = ifa->ifa_broadaddr;
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broadaddr_size = SA_LEN(broadaddr);
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} else {
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broadaddr = NULL;
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broadaddr_size = 0;
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}
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if (ifa->ifa_flags & IFF_POINTOPOINT &&
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ifa->ifa_dstaddr != NULL) {
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dstaddr = ifa->ifa_dstaddr;
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dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
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} else {
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dstaddr = NULL;
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dstaddr_size = 0;
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}
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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, ifa->ifa_name,
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ifa->ifa_flags, addr, addr_size, netmask, addr_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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freeifaddrs(ifap);
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if (ret != -1) {
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/*
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* We haven't had any errors yet; do any platform-specific
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* operations to add devices.
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*/
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if (pcap_platform_finddevs(&devlist, errbuf) < 0)
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ret = -1;
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}
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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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