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/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
/*
 * Copyright (c) 1994, 1995, 1996, 1997, 1998
 *      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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <net/if.h>

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ifaddrs.h>

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

/*
 * We don't do this on Solaris 11 and later, as it appears there aren't
 * any AF_PACKET addresses on interfaces, so we don't need this, and
 * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
 * and their definitions of some data structures collide.
 */
#if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
# ifdef HAVE_NETPACKET_PACKET_H
/* Linux distributions with newer glibc */
#  include <netpacket/packet.h>
# else /* HAVE_NETPACKET_PACKET_H */
/* LynxOS, Linux distributions with older glibc */
# ifdef __Lynx__
/* LynxOS */
#  include <netpacket/if_packet.h>
# else /* __Lynx__ */
/* Linux */
#  include <linux/types.h>
#  include <linux/if_packet.h>
# endif /* __Lynx__ */
# endif /* HAVE_NETPACKET_PACKET_H */
#endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */

/*
 * This is fun.
 *
 * In older BSD systems, socket addresses were fixed-length, and
 * "sizeof (struct sockaddr)" gave the size of the structure.
 * All addresses fit within a "struct sockaddr".
 *
 * In newer BSD systems, the socket address is variable-length, and
 * there's an "sa_len" field giving the length of the structure;
 * this allows socket addresses to be longer than 2 bytes of family
 * and 14 bytes of data.
 *
 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
 * than "struct sockaddr"), and some use the new BSD scheme.
 *
 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
 * macro that determines the size based on the address family.  Other
 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
 * but not in the final version).  On the latter systems, we explicitly
 * check the AF_ type to determine the length; we assume that on
 * all those systems we have "struct sockaddr_storage".
 */
#ifndef SA_LEN
#ifdef HAVE_SOCKADDR_SA_LEN
#define SA_LEN(addr)    ((addr)->sa_len)
#else /* HAVE_SOCKADDR_SA_LEN */
#ifdef HAVE_SOCKADDR_STORAGE
static size_t
get_sa_len(struct sockaddr *addr)
{
        switch (addr->sa_family) {

#ifdef AF_INET
        case AF_INET:
                return (sizeof (struct sockaddr_in));
#endif

#ifdef AF_INET6
        case AF_INET6:
                return (sizeof (struct sockaddr_in6));
#endif

#if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
        case AF_PACKET:
                return (sizeof (struct sockaddr_ll));
#endif

        default:
                return (sizeof (struct sockaddr));
        }
}
#define SA_LEN(addr)    (get_sa_len(addr))
#else /* HAVE_SOCKADDR_STORAGE */
#define SA_LEN(addr)    (sizeof (struct sockaddr))
#endif /* HAVE_SOCKADDR_STORAGE */
#endif /* HAVE_SOCKADDR_SA_LEN */
#endif /* SA_LEN */

/*
 * Get a list of all interfaces that are up and that we can open.
 * Returns -1 on error, 0 otherwise.
 * The list, as returned through "alldevsp", may be null if no interfaces
 * could be opened.
 */
int
pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
{
        pcap_if_t *devlist = NULL;
        struct ifaddrs *ifap, *ifa;
        struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
        size_t addr_size, broadaddr_size, dstaddr_size;
        int ret = 0;
        char *p, *q;

        /*
         * Get the list of interface addresses.
         *
         * Note: this won't return information about interfaces
         * with no addresses, so, if a platform has interfaces
         * with no interfaces on which traffic can be captured,
         * we must check for those interfaces as well (see, for
         * example, what's done on Linux).
         *
         * LAN interfaces will probably have link-layer
         * addresses; I don't know whether all implementations
         * of "getifaddrs()" now, or in the future, will return
         * those.
         */
        if (getifaddrs(&ifap) != 0) {
                (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                    "getifaddrs: %s", pcap_strerror(errno));
                return (-1);
        }
        for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
                /*
                 * "ifa_addr" was apparently null on at least one
                 * interface on some system.  Therefore, we supply
                 * the address and netmask only if "ifa_addr" is
                 * non-null (if there's no address, there's obviously
                 * no netmask).
                 */
                if (ifa->ifa_addr != NULL) {
                        addr = ifa->ifa_addr;
                        addr_size = SA_LEN(addr);
                        netmask = ifa->ifa_netmask;
                } else {
                        addr = NULL;
                        addr_size = 0;
                        netmask = NULL;
                }

                /*
                 * Note that, on some platforms, ifa_broadaddr and
                 * ifa_dstaddr could be the same field (true on at
                 * least some versions of *BSD and OS X), so we
                 * can't just check whether the broadcast address
                 * is null and add it if so and check whether the
                 * destination address is null and add it if so.
                 *
                 * Therefore, we must also check the IFF_BROADCAST
                 * flag, and only add a broadcast address if it's
                 * set, and check the IFF_POINTTOPOINT flag, and
                 * only add a destination address if it's set (as
                 * per man page recommendations on some of those
                 * platforms).
                 */
                if (ifa->ifa_flags & IFF_BROADCAST &&
                    ifa->ifa_broadaddr != NULL) {
                        broadaddr = ifa->ifa_broadaddr;
                        broadaddr_size = SA_LEN(broadaddr);
                } else {
                        broadaddr = NULL;
                        broadaddr_size = 0;
                }
                if (ifa->ifa_flags & IFF_POINTOPOINT &&
                    ifa->ifa_dstaddr != NULL) {
                        dstaddr = ifa->ifa_dstaddr;
                        dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
                } else {
                        dstaddr = NULL;
                        dstaddr_size = 0;
                }

                /*
                 * If this entry has a colon followed by a number at
                 * the end, we assume it's a logical interface.  Those
                 * are just the way you assign multiple IP addresses to
                 * a real interface on Linux, so an entry for a logical
                 * interface should be treated like the entry for the
                 * real interface; we do that by stripping off the ":"
                 * and the number.
                 *
                 * XXX - should we do this only on Linux?
                 */
                p = strchr(ifa->ifa_name, ':');
                if (p != NULL) {
                        /*
                         * We have a ":"; is it followed by a number?
                         */
                        q = p + 1;
                        while (isdigit((unsigned char)*q))
                                q++;
                        if (*q == '\0') {
                                /*
                                 * All digits after the ":" until the end.
                                 * Strip off the ":" and everything after
                                 * it.
                                 */
                               *p = '\0';
                        }
                }

                /*
                 * Add information for this address to the list.
                 */
                if (add_addr_to_iflist(&devlist, ifa->ifa_name,
                    ifa->ifa_flags, addr, addr_size, netmask, addr_size,
                    broadaddr, broadaddr_size, dstaddr, dstaddr_size,
                    errbuf) < 0) {
                        ret = -1;
                        break;
                }
        }

        freeifaddrs(ifap);

        if (ret == -1) {
                /*
                 * We had an error; free the list we've been constructing.
                 */
                if (devlist != NULL) {
                        pcap_freealldevs(devlist);
                        devlist = NULL;
                }
        }

        *alldevsp = devlist;
        return (ret);
}