/* -*- 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.

 */

#include <config.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <net/if.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.

 */

#ifdef __linux__

#include <netpacket/packet.h>

#endif

/*

 * 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".

 *

 * OSes that use this file are:

 * - FreeBSD (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)

 * - Haiku (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)

 * - Hurd (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)

 * - illumos (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)

 * - Linux (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)

 * - macOS (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)

 * - NetBSD (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)

 * - OpenBSD (SA_LEN() is defined)

 * - Solaris 11 (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)

 */

#ifndef SA_LEN

#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN

#define SA_LEN(addr)  ((addr)->sa_len)

#else /* HAVE_STRUCT_SOCKADDR_SA_LEN */

static size_t

get_sa_len(struct sockaddr *addr)

{

  switch (addr->sa_family) {

  case AF_INET:

    return (sizeof (struct sockaddr_in));

  case AF_INET6:

    return (sizeof (struct sockaddr_in6));

#if defined(__linux__)

  case AF_PACKET:

    return (sizeof (struct sockaddr_ll));

#endif

#ifdef AF_LINK

  case AF_LINK:

    return (sizeof (struct sockaddr_dl));

#endif

  default:

    return (sizeof (struct sockaddr));

  }

}

#define SA_LEN(addr)  (get_sa_len(addr))

#endif /* HAVE_STRUCT_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

pcapint_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,

    int (*check_usable)(const char *), get_if_flags_func get_flags_func)

{

  struct ifaddrs *ifap, *ifa;

  struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;

  size_t addr_size, netmask_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) {

    pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

        errno, "getifaddrs");

    return (-1);

  }

  for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {

    /*

     * 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 (PCAP_ISDIGIT(*q))

        q++;

      if (*q == '\0') {

        /*

         * All digits after the ":" until the end.

         * Strip off the ":" and everything after

         * it.

         */

             *p = '\0';

      }

    }

    /*

     * Can we capture on this device?

     */

    if (!(*check_usable)(ifa->ifa_name)) {

      /*

       * No.

       */

      continue;

    }

    /*

     * "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);

      if (ifa->ifa_netmask != NULL) {

        netmask = ifa->ifa_netmask;

        netmask_size = SA_LEN(ifa->ifa_netmask);

      } else {

        netmask = NULL;

        netmask_size = 0;

      }

    } else {

      addr = NULL;

      addr_size = 0;

      netmask = NULL;

      netmask_size = 0;

    }

    /*

     * Note that, on some platforms, ifa_broadaddr and

     * ifa_dstaddr could be the same field (true on at

     * least some versions of *BSD and macOS), 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;

    }

    /*

     * Add information for this address to the list.

     */

    if (pcapint_add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags,

        get_flags_func,

        addr, addr_size, netmask, netmask_size,

        broadaddr, broadaddr_size, dstaddr, dstaddr_size,

        errbuf) < 0) {

      ret = -1;

      break;

    }

  }

  freeifaddrs(ifap);

  return (ret);

}