/src/libpcap/pcap.c

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/*
 * Copyright (c) 1993, 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 <pcap-types.h>
#ifndef _WIN32
#include <sys/param.h>
#ifndef MSDOS
#include <sys/file.h>
#endif
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif

struct mbuf;    /* Squelch compiler warnings on some platforms for */
struct rtentry;   /* declarations in <net/if.h> */
#include <net/if.h>
#include <netinet/in.h>
#endif /* _WIN32 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if !defined(_MSC_VER) && !defined(__BORLANDC__) && !defined(__MINGW32__)
#include <unistd.h>
#endif
#include <fcntl.h>
#include <errno.h>
#include <limits.h>

#include "diag-control.h"

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

#ifdef MSDOS
#include "pcap-dos.h"
#endif

#include "pcap-int.h"

#include "optimize.h"

#ifdef HAVE_DAG_API
#include "pcap-dag.h"
#endif /* HAVE_DAG_API */

#ifdef HAVE_SEPTEL_API
#include "pcap-septel.h"
#endif /* HAVE_SEPTEL_API */

#ifdef HAVE_SNF_API
#include "pcap-snf.h"
#endif /* HAVE_SNF_API */

#ifdef HAVE_TC_API
#include "pcap-tc.h"
#endif /* HAVE_TC_API */

#ifdef PCAP_SUPPORT_LINUX_USBMON
#include "pcap-usb-linux.h"
#endif

#ifdef PCAP_SUPPORT_BT
#include "pcap-bt-linux.h"
#endif

#ifdef PCAP_SUPPORT_BT_MONITOR
#include "pcap-bt-monitor-linux.h"
#endif

#ifdef PCAP_SUPPORT_NETFILTER
#include "pcap-netfilter-linux.h"
#endif

#ifdef PCAP_SUPPORT_NETMAP
#include "pcap-netmap.h"
#endif

#ifdef PCAP_SUPPORT_DBUS
#include "pcap-dbus.h"
#endif

#ifdef PCAP_SUPPORT_RDMASNIFF
#include "pcap-rdmasniff.h"
#endif

#ifdef PCAP_SUPPORT_DPDK
#include "pcap-dpdk.h"
#endif

#ifdef HAVE_AIRPCAP_API
#include "pcap-airpcap.h"
#endif

#ifdef _WIN32
/*
 * To quote the WSAStartup() documentation:
 *
 *   The WSAStartup function typically leads to protocol-specific helper
 *   DLLs being loaded. As a result, the WSAStartup function should not
 *   be called from the DllMain function in a application DLL. This can
 *   potentially cause deadlocks.
 *
 * and the WSACleanup() documentation:
 *
 *   The WSACleanup function typically leads to protocol-specific helper
 *   DLLs being unloaded. As a result, the WSACleanup function should not
 *   be called from the DllMain function in a application DLL. This can
 *   potentially cause deadlocks.
 *
 * So we don't initialize Winsock in a DllMain() routine.
 *
 * pcap_init() should be called to initialize pcap on both UN*X and
 * Windows; it will initialize Winsock on Windows.  (It will also be
 * initialized as needed if pcap_init() hasn't been called.)
 */

/*
 * Start Winsock.
 * Internal routine.
 */
static int
internal_wsockinit(char *errbuf)
{
  WORD wVersionRequested;
  WSADATA wsaData;
  static int err = -1;
  static int done = 0;
  int status;

  if (done)
    return (err);

  /*
   * Versions of Windows that don't support Winsock 2.2 are
   * too old for us.
   */
  wVersionRequested = MAKEWORD(2, 2);
  status = WSAStartup(wVersionRequested, &wsaData);
  done = 1;
  if (status != 0) {
    if (errbuf != NULL) {
      pcap_fmt_errmsg_for_win32_err(errbuf, PCAP_ERRBUF_SIZE,
          status, "WSAStartup() failed");
    }
    return (err);
  }
  atexit ((void(*)(void))WSACleanup);
  err = 0;
  return (err);
}

/*
 * Exported in case some applications using WinPcap/Npcap called it,
 * even though it wasn't exported.
 */
int
wsockinit(void)
{
  return (internal_wsockinit(NULL));
}

/*
 * This is the exported function; new programs should call this.
 * *Newer* programs should call pcap_init().
 */
int
pcap_wsockinit(void)
{
  return (internal_wsockinit(NULL));
}
#endif /* _WIN32 */

/*
 * Do whatever initialization is needed for libpcap.
 *
 * The argument specifies whether we use the local code page or UTF-8
 * for strings; on UN*X, we just assume UTF-8 in places where the encoding
 * would matter, whereas, on Windows, we use the local code page for
 * PCAP_CHAR_ENC_LOCAL and UTF-8 for PCAP_CHAR_ENC_UTF_8.
 *
 * On Windows, we also disable the hack in pcap_create() to deal with
 * being handed UTF-16 strings, because if the user calls this they're
 * explicitly declaring that they will either be passing local code
 * page strings or UTF-8 strings, so we don't need to allow UTF-16LE
 * strings to be passed.  For good measure, on Windows *and* UN*X,
 * we disable pcap_lookupdev(), to prevent anybody from even
 * *trying* to pass the result of pcap_lookupdev() - which might be
 * UTF-16LE on Windows, for ugly compatibility reasons - to pcap_create()
 * or pcap_open_live() or pcap_open().
 *
 * Returns 0 on success, -1 on error.
 */
int pcap_new_api;   /* pcap_lookupdev() always fails */
int pcap_utf_8_mode;    /* Strings should be in UTF-8. */
int pcap_mmap_32bit;    /* Map packet buffers with 32-bit addresses. */

int
pcap_init(unsigned int opts, char *errbuf)
{
  static int initialized;

  /*
   * Don't allow multiple calls that set different modes; that
   * may mean a library is initializing pcap in one mode and
   * a program using that library, or another library used by
   * that program, is initializing it in another mode.
   */
  switch (opts) {

  case PCAP_CHAR_ENC_LOCAL:
    /* Leave "UTF-8 mode" off. */
    if (initialized) {
      if (pcap_utf_8_mode) {
        snprintf(errbuf, PCAP_ERRBUF_SIZE,
            "Multiple pcap_init calls with different character encodings");
        return (PCAP_ERROR);
      }
    }
    break;

  case PCAP_CHAR_ENC_UTF_8:
    /* Turn on "UTF-8 mode". */
    if (initialized) {
      if (!pcap_utf_8_mode) {
        snprintf(errbuf, PCAP_ERRBUF_SIZE,
            "Multiple pcap_init calls with different character encodings");
        return (PCAP_ERROR);
      }
    }
    pcap_utf_8_mode = 1;
    break;

  case PCAP_MMAP_32BIT:
    pcap_mmap_32bit = 1;
    break;

  default:
    snprintf(errbuf, PCAP_ERRBUF_SIZE, "Unknown options specified");
    return (PCAP_ERROR);
  }

  /*
   * Turn the appropriate mode on for error messages; those routines
   * are also used in rpcapd, which has no access to pcap's internal
   * UTF-8 mode flag, so we have to call a routine to set its
   * UTF-8 mode flag.
   */
  pcap_fmt_set_encoding(opts);

  if (initialized) {
    /*
     * Nothing more to do; for example, on Windows, we've
     * already initialized Winsock.
     */
    return (0);
  }

#ifdef _WIN32
  /*
   * Now set up Winsock.
   */
  if (internal_wsockinit(errbuf) == -1) {
    /* Failed. */
    return (PCAP_ERROR);
  }
#endif

  /*
   * We're done.
   */
  initialized = 1;
  pcap_new_api = 1;
  return (0);
}

/*
 * String containing the library version.
 * Not explicitly exported via a header file - the right API to use
 * is pcap_lib_version() - but some programs included it, so we
 * provide it.
 *
 * We declare it here, right before defining it, to squelch any
 * warnings we might get from compilers about the lack of a
 * declaration.
 */
PCAP_API char pcap_version[];
PCAP_API_DEF char pcap_version[] = PACKAGE_VERSION;

static void
pcap_set_not_initialized_message(pcap_t *pcap)
{
  if (pcap->activated) {
    /* A module probably forgot to set the function pointer */
    (void)snprintf(pcap->errbuf, sizeof(pcap->errbuf),
        "This operation isn't properly handled by that device");
    return;
  }
  /* in case the caller doesn't check for PCAP_ERROR_NOT_ACTIVATED */
  (void)snprintf(pcap->errbuf, sizeof(pcap->errbuf),
      "This handle hasn't been activated yet");
}

static int
pcap_read_not_initialized(pcap_t *pcap, int cnt _U_, pcap_handler callback _U_,
    u_char *user _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_inject_not_initialized(pcap_t *pcap, const void * buf _U_, int size _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_setfilter_not_initialized(pcap_t *pcap, struct bpf_program *fp _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_setdirection_not_initialized(pcap_t *pcap, pcap_direction_t d _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_set_datalink_not_initialized(pcap_t *pcap, int dlt _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_getnonblock_not_initialized(pcap_t *pcap)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_stats_not_initialized(pcap_t *pcap, struct pcap_stat *ps _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

#ifdef _WIN32
static struct pcap_stat *
pcap_stats_ex_not_initialized(pcap_t *pcap, int *pcap_stat_size _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (NULL);
}

static int
pcap_setbuff_not_initialized(pcap_t *pcap, int dim _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_setmode_not_initialized(pcap_t *pcap, int mode _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_setmintocopy_not_initialized(pcap_t *pcap, int size _U_)
{
  pcap_set_not_initialized_message(pcap);
  /* this means 'not initialized' */
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static HANDLE
pcap_getevent_not_initialized(pcap_t *pcap)
{
  pcap_set_not_initialized_message(pcap);
  return (INVALID_HANDLE_VALUE);
}

static int
pcap_oid_get_request_not_initialized(pcap_t *pcap, bpf_u_int32 oid _U_,
    void *data _U_, size_t *lenp _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_oid_set_request_not_initialized(pcap_t *pcap, bpf_u_int32 oid _U_,
    const void *data _U_, size_t *lenp _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static u_int
pcap_sendqueue_transmit_not_initialized(pcap_t *pcap, pcap_send_queue* queue _U_,
    int sync _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (0);
}

static int
pcap_setuserbuffer_not_initialized(pcap_t *pcap, int size _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_live_dump_not_initialized(pcap_t *pcap, char *filename _U_, int maxsize _U_,
    int maxpacks _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static int
pcap_live_dump_ended_not_initialized(pcap_t *pcap, int sync _U_)
{
  pcap_set_not_initialized_message(pcap);
  return (PCAP_ERROR_NOT_ACTIVATED);
}

static PAirpcapHandle
pcap_get_airpcap_handle_not_initialized(pcap_t *pcap)
{
  pcap_set_not_initialized_message(pcap);
  return (NULL);
}
#endif

/*
 * Returns 1 if rfmon mode can be set on the pcap_t, 0 if it can't,
 * a PCAP_ERROR value on an error.
 */
int
pcap_can_set_rfmon(pcap_t *p)
{
  return (p->can_set_rfmon_op(p));
}

/*
 * For systems where rfmon mode is never supported.
 */
static int
pcap_cant_set_rfmon(pcap_t *p _U_)
{
  return (0);
}

/*
 * Sets *tstamp_typesp to point to an array 1 or more supported time stamp
 * types; the return value is the number of supported time stamp types.
 * The list should be freed by a call to pcap_free_tstamp_types() when
 * you're done with it.
 *
 * A return value of 0 means "you don't get a choice of time stamp type",
 * in which case *tstamp_typesp is set to null.
 *
 * PCAP_ERROR is returned on error.
 */
int
pcap_list_tstamp_types(pcap_t *p, int **tstamp_typesp)
{
  if (p->tstamp_type_count == 0) {
    /*
     * We don't support multiple time stamp types.
     * That means the only type we support is PCAP_TSTAMP_HOST;
     * set up a list containing only that type.
     */
    *tstamp_typesp = (int*)malloc(sizeof(**tstamp_typesp));
    if (*tstamp_typesp == NULL) {
      pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
          errno, "malloc");
      return (PCAP_ERROR);
    }
    **tstamp_typesp = PCAP_TSTAMP_HOST;
    return (1);
  } else {
    *tstamp_typesp = (int*)calloc(sizeof(**tstamp_typesp),
        p->tstamp_type_count);
    if (*tstamp_typesp == NULL) {
      pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
          errno, "malloc");
      return (PCAP_ERROR);
    }
    (void)memcpy(*tstamp_typesp, p->tstamp_type_list,
        sizeof(**tstamp_typesp) * p->tstamp_type_count);
    return (p->tstamp_type_count);
  }
}

/*
 * In Windows, you might have a library built with one version of the
 * C runtime library and an application built with another version of
 * the C runtime library, which means that the library might use one
 * version of malloc() and free() and the application might use another
 * version of malloc() and free().  If so, that means something
 * allocated by the library cannot be freed by the application, so we
 * need to have a pcap_free_tstamp_types() routine to free up the list
 * allocated by pcap_list_tstamp_types(), even though it's just a wrapper
 * around free().
 */
void
pcap_free_tstamp_types(int *tstamp_type_list)
{
  free(tstamp_type_list);
}

/*
 * Default one-shot callback; overridden for capture types where the
 * packet data cannot be guaranteed to be available after the callback
 * returns, so that a copy must be made.
 */
void
pcap_oneshot(u_char *user, const struct pcap_pkthdr *h, const u_char *pkt)
{
  struct oneshot_userdata *sp = (struct oneshot_userdata *)user;

  *sp->hdr = *h;
  *sp->pkt = pkt;
}

const u_char *
pcap_next(pcap_t *p, struct pcap_pkthdr *h)
{
  struct oneshot_userdata s;
  const u_char *pkt;

  s.hdr = h;
  s.pkt = &pkt;
  s.pd = p;
  if (pcap_dispatch(p, 1, p->oneshot_callback, (u_char *)&s) <= 0)
    return (0);
  return (pkt);
}

int
pcap_next_ex(pcap_t *p, struct pcap_pkthdr **pkt_header,
    const u_char **pkt_data)
{
  struct oneshot_userdata s;

  s.hdr = &p->pcap_header;
  s.pkt = pkt_data;
  s.pd = p;

  /* Saves a pointer to the packet headers */
  *pkt_header= &p->pcap_header;

  if (p->rfile != NULL) {
    int status;

    /* We are on an offline capture */
    status = pcap_offline_read(p, 1, p->oneshot_callback,
        (u_char *)&s);

    /*
     * Return codes for pcap_offline_read() are:
     *   -  0: EOF
     *   - -1: error
     *   - >0: OK - result is number of packets read, so
     *         it will be 1 in this case, as we've passed
     *         a maximum packet count of 1
     * The first one ('0') conflicts with the return code of
     * 0 from pcap_read() meaning "no packets arrived before
     * the timeout expired", so we map it to -2 so you can
     * distinguish between an EOF from a savefile and a
     * "no packets arrived before the timeout expired, try
     * again" from a live capture.
     */
    if (status == 0)
      return (-2);
    else
      return (status);
  }

  /*
   * Return codes for pcap_read() are:
   *   -  0: timeout
   *   - -1: error
   *   - -2: loop was broken out of with pcap_breakloop()
   *   - >0: OK, result is number of packets captured, so
   *         it will be 1 in this case, as we've passed
   *         a maximum packet count of 1
   * The first one ('0') conflicts with the return code of 0 from
   * pcap_offline_read() meaning "end of file".
  */
  return (p->read_op(p, 1, p->oneshot_callback, (u_char *)&s));
}

/*
 * Implementation of a pcap_if_list_t.
 */
struct pcap_if_list {
  pcap_if_t *beginning;
};

static struct capture_source_type {
  int (*findalldevs_op)(pcap_if_list_t *, char *);
  pcap_t *(*create_op)(const char *, char *, int *);
} capture_source_types[] = {
#ifdef HAVE_DAG_API
  { dag_findalldevs, dag_create },
#endif
#ifdef HAVE_SEPTEL_API
  { septel_findalldevs, septel_create },
#endif
#ifdef HAVE_SNF_API
  { snf_findalldevs, snf_create },
#endif
#ifdef HAVE_TC_API
  { TcFindAllDevs, TcCreate },
#endif
#ifdef PCAP_SUPPORT_BT
  { bt_findalldevs, bt_create },
#endif
#ifdef PCAP_SUPPORT_BT_MONITOR
  { bt_monitor_findalldevs, bt_monitor_create },
#endif
#ifdef PCAP_SUPPORT_LINUX_USBMON
  { usb_findalldevs, usb_create },
#endif
#ifdef PCAP_SUPPORT_NETFILTER
  { netfilter_findalldevs, netfilter_create },
#endif
#ifdef PCAP_SUPPORT_NETMAP
  { pcap_netmap_findalldevs, pcap_netmap_create },
#endif
#ifdef PCAP_SUPPORT_DBUS
  { dbus_findalldevs, dbus_create },
#endif
#ifdef PCAP_SUPPORT_RDMASNIFF
  { rdmasniff_findalldevs, rdmasniff_create },
#endif
#ifdef PCAP_SUPPORT_DPDK
  { pcap_dpdk_findalldevs, pcap_dpdk_create },
#endif
#ifdef HAVE_AIRPCAP_API
  { airpcap_findalldevs, airpcap_create },
#endif
  { NULL, NULL }
};

/*
 * Get a list of all capture sources 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
 * were up and could be opened.
 */
int
pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
{
  size_t i;
  pcap_if_list_t devlist;

  /*
   * Find all the local network interfaces on which we
   * can capture.
   */
  devlist.beginning = NULL;
  if (pcap_platform_finddevs(&devlist, errbuf) == -1) {
    /*
     * Failed - free all of the entries we were given
     * before we failed.
     */
    if (devlist.beginning != NULL)
      pcap_freealldevs(devlist.beginning);
    *alldevsp = NULL;
    return (-1);
  }

  /*
   * Ask each of the non-local-network-interface capture
   * source types what interfaces they have.
   */
  for (i = 0; capture_source_types[i].findalldevs_op != NULL; i++) {
    if (capture_source_types[i].findalldevs_op(&devlist, errbuf) == -1) {
      /*
       * We had an error; free the list we've been
       * constructing.
       */
      if (devlist.beginning != NULL)
        pcap_freealldevs(devlist.beginning);
      *alldevsp = NULL;
      return (-1);
    }
  }

  /*
   * Return the first entry of the list of all devices.
   */
  *alldevsp = devlist.beginning;
  return (0);
}

static struct sockaddr *
dup_sockaddr(struct sockaddr *sa, size_t sa_length)
{
  struct sockaddr *newsa;

  if ((newsa = malloc(sa_length)) == NULL)
    return (NULL);
  return (memcpy(newsa, sa, sa_length));
}

/*
 * Construct a "figure of merit" for an interface, for use when sorting
 * the list of interfaces, in which interfaces that are up are superior
 * to interfaces that aren't up, interfaces that are up and running are
 * superior to interfaces that are up but not running, and non-loopback
 * interfaces that are up and running are superior to loopback interfaces,
 * and interfaces with the same flags have a figure of merit that's higher
 * the lower the instance number.
 *
 * The goal is to try to put the interfaces most likely to be useful for
 * capture at the beginning of the list.
 *
 * The figure of merit, which is lower the "better" the interface is,
 * has the uppermost bit set if the interface isn't running, the bit
 * below that set if the interface isn't up, the bit below that
 * set if the interface is a loopback interface, and the bit below
 * that set if it's the "any" interface.
 *
 * Note: we don't sort by unit number because 1) not all interfaces have
 * a unit number (systemd, for example, might assign interface names
 * based on the interface's MAC address or on the physical location of
 * the adapter's connector), and 2) if the name does end with a simple
 * unit number, it's not a global property of the interface, it's only
 * useful as a sort key for device names with the same prefix, so xyz0
 * shouldn't necessarily sort before abc2.  This means that interfaces
 * with the same figure of merit will be sorted by the order in which
 * the mechanism from which we're getting the interfaces supplies them.
 */
static u_int
get_figure_of_merit(pcap_if_t *dev)
{
  u_int n;

  n = 0;
  if (!(dev->flags & PCAP_IF_RUNNING))
    n |= 0x80000000;
  if (!(dev->flags & PCAP_IF_UP))
    n |= 0x40000000;

  /*
   * Give non-wireless interfaces that aren't disconnected a better
   * figure of merit than interfaces that are disconnected, as
   * "disconnected" should indicate that the interface isn't
   * plugged into a network and thus won't give you any traffic.
   *
   * For wireless interfaces, it means "associated with a network",
   * which we presume not to necessarily prevent capture, as you
   * might run the adapter in some flavor of monitor mode.
   */
  if (!(dev->flags & PCAP_IF_WIRELESS) &&
      (dev->flags & PCAP_IF_CONNECTION_STATUS) == PCAP_IF_CONNECTION_STATUS_DISCONNECTED)
    n |= 0x20000000;

  /*
   * Sort loopback devices after non-loopback devices, *except* for
   * disconnected devices.
   */
  if (dev->flags & PCAP_IF_LOOPBACK)
    n |= 0x10000000;

  /*
   * Sort the "any" device before loopback and disconnected devices,
   * but after all other devices.
   */
  if (strcmp(dev->name, "any") == 0)
    n |= 0x08000000;

  return (n);
}

#ifndef _WIN32
/*
 * Try to get a description for a given device.
 * Returns a mallocated description if it could and NULL if it couldn't.
 *
 * XXX - on FreeBSDs that support it, should it get the sysctl named
 * "dev.{adapter family name}.{adapter unit}.%desc" to get a description
 * of the adapter?  Note that "dev.an.0.%desc" is "Aironet PC4500/PC4800"
 * with my Cisco 350 card, so the name isn't entirely descriptive.  The
 * "dev.an.0.%pnpinfo" has a better description, although one might argue
 * that the problem is really a driver bug - if it can find out that it's
 * a Cisco 340 or 350, rather than an old Aironet card, it should use
 * that in the description.
 *
 * Do NetBSD, DragonflyBSD, or OpenBSD support this as well?  FreeBSD
 * and OpenBSD let you get a description, but it's not generated by the OS,
 * it's set with another ioctl that ifconfig supports; we use that to get
 * a description in FreeBSD and OpenBSD, but if there is no such
 * description available, it still might be nice to get some description
 * string based on the device type or something such as that.
 *
 * In macOS, the System Configuration framework can apparently return
 * names in 10.4 and later.
 *
 * It also appears that freedesktop.org's HAL offers an "info.product"
 * string, but the HAL specification says it "should not be used in any
 * UI" and "subsystem/capability specific properties" should be used
 * instead and, in any case, I think HAL is being deprecated in
 * favor of other stuff such as DeviceKit.  DeviceKit doesn't appear
 * to have any obvious product information for devices, but maybe
 * I haven't looked hard enough.
 *
 * Using the System Configuration framework, or HAL, or DeviceKit, or
 * whatever, would require that libpcap applications be linked with
 * the frameworks/libraries in question.  That shouldn't be a problem
 * for programs linking with the shared version of libpcap (unless
 * you're running on AIX - which I think is the only UN*X that doesn't
 * support linking a shared library with other libraries on which it
 * depends, and having an executable linked only with the first shared
 * library automatically pick up the other libraries when started -
 * and using HAL or whatever).  Programs linked with the static
 * version of libpcap would have to use pcap-config with the --static
 * flag in order to get the right linker flags in order to pick up
 * the additional libraries/frameworks; those programs need that anyway
 * for libpcap 1.1 and beyond on Linux, as, by default, it requires
 * -lnl.
 *
 * Do any other UN*Xes, or desktop environments support getting a
 * description?
 */
static char *
#ifdef SIOCGIFDESCR
get_if_description(const char *name)
{
  char *description = NULL;
  int s;
  struct ifreq ifrdesc;
#ifndef IFDESCRSIZE
  size_t descrlen = 64;
#else
  size_t descrlen = IFDESCRSIZE;
#endif /* IFDESCRSIZE */

  /*
   * Get the description for the interface.
   */
  memset(&ifrdesc, 0, sizeof ifrdesc);
  pcap_strlcpy(ifrdesc.ifr_name, name, sizeof ifrdesc.ifr_name);
  s = socket(AF_INET, SOCK_DGRAM, 0);
  if (s >= 0) {
#ifdef __FreeBSD__
    /*
     * On FreeBSD, if the buffer isn't big enough for the
     * description, the ioctl succeeds, but the description
     * isn't copied, ifr_buffer.length is set to the description
     * length, and ifr_buffer.buffer is set to NULL.
     */
    for (;;) {
      free(description);
      if ((description = malloc(descrlen)) != NULL) {
        ifrdesc.ifr_buffer.buffer = description;
        ifrdesc.ifr_buffer.length = descrlen;
        if (ioctl(s, SIOCGIFDESCR, &ifrdesc) == 0) {
          if (ifrdesc.ifr_buffer.buffer ==
              description)
            break;
          else
            descrlen = ifrdesc.ifr_buffer.length;
        } else {
          /*
           * Failed to get interface description.
           */
          free(description);
          description = NULL;
          break;
        }
      } else
        break;
    }
#else /* __FreeBSD__ */
    /*
     * The only other OS that currently supports
     * SIOCGIFDESCR is OpenBSD, and it has no way
     * to get the description length - it's clamped
     * to a maximum of IFDESCRSIZE.
     */
    if ((description = malloc(descrlen)) != NULL) {
      ifrdesc.ifr_data = (caddr_t)description;
      if (ioctl(s, SIOCGIFDESCR, &ifrdesc) != 0) {
        /*
         * Failed to get interface description.
         */
        free(description);
        description = NULL;
      }
    }
#endif /* __FreeBSD__ */
    close(s);
    if (description != NULL && description[0] == '\0') {
      /*
       * Description is empty, so discard it.
       */
      free(description);
      description = NULL;
    }
  }

#ifdef __FreeBSD__
  /*
   * For FreeBSD, if we didn't get a description, and this is
   * a device with a name of the form usbusN, label it as a USB
   * bus.
   */
  if (description == NULL) {
    if (strncmp(name, "usbus", 5) == 0) {
      /*
       * OK, it begins with "usbus".
       */
      long busnum;
      char *p;

      errno = 0;
      busnum = strtol(name + 5, &p, 10);
      if (errno == 0 && p != name + 5 && *p == '\0' &&
          busnum >= 0 && busnum <= INT_MAX) {
        /*
         * OK, it's a valid number that's not
         * bigger than INT_MAX.  Construct
         * a description from it.
         * (If that fails, we don't worry about
         * it, we just return NULL.)
         */
        if (pcap_asprintf(&description,
            "USB bus number %ld", busnum) == -1) {
          /* Failed. */
          description = NULL;
        }
      }
    }
  }
#endif
  return (description);
#else /* SIOCGIFDESCR */
get_if_description(const char *name _U_)
{
  return (NULL);
#endif /* SIOCGIFDESCR */
}

/*
 * Look for a given device in the specified list of devices.
 *
 * If we find it, return a pointer to its entry.
 *
 * If we don't find it, attempt to add an entry for it, with the specified
 * IFF_ flags and description, and, if that succeeds, return a pointer to
 * the new entry, otherwise return NULL and set errbuf to an error message.
 */
pcap_if_t *
find_or_add_if(pcap_if_list_t *devlistp, const char *name,
    bpf_u_int32 if_flags, get_if_flags_func get_flags_func, char *errbuf)
{
  bpf_u_int32 pcap_flags;

  /*
   * Convert IFF_ flags to pcap flags.
   */
  pcap_flags = 0;
#ifdef IFF_LOOPBACK
  if (if_flags & IFF_LOOPBACK)
    pcap_flags |= PCAP_IF_LOOPBACK;
#else
  /*
   * We don't have IFF_LOOPBACK, so look at the device name to
   * see if it looks like a loopback device.
   */
  if (name[0] == 'l' && name[1] == 'o' &&
      (PCAP_ISDIGIT(name[2]) || name[2] == '\0'))
    pcap_flags |= PCAP_IF_LOOPBACK;
#endif
#ifdef IFF_UP
  if (if_flags & IFF_UP)
    pcap_flags |= PCAP_IF_UP;
#endif
#ifdef IFF_RUNNING
  if (if_flags & IFF_RUNNING)
    pcap_flags |= PCAP_IF_RUNNING;
#endif

  /*
   * Attempt to find an entry for this device; if we don't find one,
   * attempt to add one.
   */
  return (find_or_add_dev(devlistp, name, pcap_flags,
      get_flags_func, get_if_description(name), errbuf));
}

/*
 * Look for a given device in the specified list of devices.
 *
 * If we find it, then, if the specified address isn't null, add it to
 * the list of addresses for the device and return 0.
 *
 * If we don't find it, attempt to add an entry for it, with the specified
 * IFF_ flags and description, and, if that succeeds, add the specified
 * address to its list of addresses if that address is non-null, and
 * return 0, otherwise return -1 and set errbuf to an error message.
 *
 * (We can get called with a null address because we might get a list
 * of interface name/address combinations from the underlying OS, with
 * the address being absent in some cases, rather than a list of
 * interfaces with each interface having a list of addresses, so this
 * call may be the only call made to add to the list, and we want to
 * add interfaces even if they have no addresses.)
 */
int
add_addr_to_if(pcap_if_list_t *devlistp, const char *name,
    bpf_u_int32 if_flags, get_if_flags_func get_flags_func,
    struct sockaddr *addr, size_t addr_size,
    struct sockaddr *netmask, size_t netmask_size,
    struct sockaddr *broadaddr, size_t broadaddr_size,
    struct sockaddr *dstaddr, size_t dstaddr_size,
    char *errbuf)
{
  pcap_if_t *curdev;

  /*
   * Check whether the device exists and, if not, add it.
   */
  curdev = find_or_add_if(devlistp, name, if_flags, get_flags_func,
      errbuf);
  if (curdev == NULL) {
    /*
     * Error - give up.
     */
    return (-1);
  }

  if (addr == NULL) {
    /*
     * There's no address to add; this entry just meant
     * "here's a new interface".
     */
    return (0);
  }

  /*
   * "curdev" is an entry for this interface, and we have an
   * address for it; add an entry for that address to the
   * interface's list of addresses.
   */
  return (add_addr_to_dev(curdev, addr, addr_size, netmask,
      netmask_size, broadaddr, broadaddr_size, dstaddr,
      dstaddr_size, errbuf));
}
#endif /* _WIN32 */

/*
 * Add an entry to the list of addresses for an interface.
 * "curdev" is the entry for that interface.
 */
int
add_addr_to_dev(pcap_if_t *curdev,
    struct sockaddr *addr, size_t addr_size,
    struct sockaddr *netmask, size_t netmask_size,
    struct sockaddr *broadaddr, size_t broadaddr_size,
    struct sockaddr *dstaddr, size_t dstaddr_size,
    char *errbuf)
{
  pcap_addr_t *curaddr, *prevaddr, *nextaddr;

  /*
   * Allocate the new entry and fill it in.
   */
  curaddr = (pcap_addr_t *)malloc(sizeof(pcap_addr_t));
  if (curaddr == NULL) {
    pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    return (-1);
  }

  curaddr->next = NULL;
  if (addr != NULL && addr_size != 0) {
    curaddr->addr = (struct sockaddr *)dup_sockaddr(addr, addr_size);
    if (curaddr->addr == NULL) {
      pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      free(curaddr);
      return (-1);
    }
  } else
    curaddr->addr = NULL;

  if (netmask != NULL && netmask_size != 0) {
    curaddr->netmask = (struct sockaddr *)dup_sockaddr(netmask, netmask_size);
    if (curaddr->netmask == NULL) {
      pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      if (curaddr->addr != NULL)
        free(curaddr->addr);
      free(curaddr);
      return (-1);
    }
  } else
    curaddr->netmask = NULL;

  if (broadaddr != NULL && broadaddr_size != 0) {
    curaddr->broadaddr = (struct sockaddr *)dup_sockaddr(broadaddr, broadaddr_size);
    if (curaddr->broadaddr == NULL) {
      pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      if (curaddr->netmask != NULL)
        free(curaddr->netmask);
      if (curaddr->addr != NULL)
        free(curaddr->addr);
      free(curaddr);
      return (-1);
    }
  } else
    curaddr->broadaddr = NULL;

  if (dstaddr != NULL && dstaddr_size != 0) {
    curaddr->dstaddr = (struct sockaddr *)dup_sockaddr(dstaddr, dstaddr_size);
    if (curaddr->dstaddr == NULL) {
      pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      if (curaddr->broadaddr != NULL)
        free(curaddr->broadaddr);
      if (curaddr->netmask != NULL)
        free(curaddr->netmask);
      if (curaddr->addr != NULL)
        free(curaddr->addr);
      free(curaddr);
      return (-1);
    }
  } else
    curaddr->dstaddr = NULL;

  /*
   * Find the end of the list of addresses.
   */
  for (prevaddr = curdev->addresses; prevaddr != NULL; prevaddr = nextaddr) {
    nextaddr = prevaddr->next;
    if (nextaddr == NULL) {
      /*
       * This is the end of the list.
       */
      break;
    }
  }

  if (prevaddr == NULL) {
    /*
     * The list was empty; this is the first member.
     */
    curdev->addresses = curaddr;
  } else {
    /*
     * "prevaddr" is the last member of the list; append
     * this member to it.
     */
    prevaddr->next = curaddr;
  }

  return (0);
}

/*
 * Look for a given device in the specified list of devices.
 *
 * If we find it, return 0 and set *curdev_ret to point to it.
 *
 * If we don't find it, attempt to add an entry for it, with the specified
 * flags and description, and, if that succeeds, return 0, otherwise
 * return -1 and set errbuf to an error message.
 */
pcap_if_t *
find_or_add_dev(pcap_if_list_t *devlistp, const char *name, bpf_u_int32 flags,
    get_if_flags_func get_flags_func, const char *description, char *errbuf)
{
  pcap_if_t *curdev;

  /*
   * Is there already an entry in the list for this device?
   */
  curdev = find_dev(devlistp, name);
  if (curdev != NULL) {
    /*
     * Yes, return it.
     */
    return (curdev);
  }

  /*
   * No, we didn't find it.
   */

  /*
   * Try to get additional flags for the device.
   */
  if ((*get_flags_func)(name, &flags, errbuf) == -1) {
    /*
     * Failed.
     */
    return (NULL);
  }

  /*
   * Now, try to add it to the list of devices.
   */
  return (add_dev(devlistp, name, flags, description, errbuf));
}

/*
 * Look for a given device in the specified list of devices, and return
 * the entry for it if we find it or NULL if we don't.
 */
pcap_if_t *
find_dev(pcap_if_list_t *devlistp, const char *name)
{
  pcap_if_t *curdev;

  /*
   * Is there an entry in the list for this device?
   */
  for (curdev = devlistp->beginning; curdev != NULL;
      curdev = curdev->next) {
    if (strcmp(name, curdev->name) == 0) {
      /*
       * We found it, so, yes, there is.  No need to
       * add it.  Provide the entry we found to our
       * caller.
       */
      return (curdev);
    }
  }

  /*
   * No.
   */
  return (NULL);
}

/*
 * Attempt to add an entry for a device, with the specified flags
 * and description, and, if that succeeds, return 0 and return a pointer
 * to the new entry, otherwise return NULL and set errbuf to an error
 * message.
 *
 * If we weren't given a description, try to get one.
 */
pcap_if_t *
add_dev(pcap_if_list_t *devlistp, const char *name, bpf_u_int32 flags,
    const char *description, char *errbuf)
{
  pcap_if_t *curdev, *prevdev, *nextdev;
  u_int this_figure_of_merit, nextdev_figure_of_merit;

  curdev = malloc(sizeof(pcap_if_t));
  if (curdev == NULL) {
    pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    return (NULL);
  }

  /*
   * Fill in the entry.
   */
  curdev->next = NULL;
  curdev->name = strdup(name);
  if (curdev->name == NULL) {
    pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    free(curdev);
    return (NULL);
  }
  if (description == NULL) {
    /*
     * We weren't handed a description for the interface.
     */
    curdev->description = NULL;
  } else {
    /*
     * We were handed a description; make a copy.
     */
    curdev->description = strdup(description);
    if (curdev->description == NULL) {
      pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      free(curdev->name);
      free(curdev);
      return (NULL);
    }
  }
  curdev->addresses = NULL; /* list starts out as empty */
  curdev->flags = flags;

  /*
   * Add it to the list, in the appropriate location.
   * First, get the "figure of merit" for this interface.
   */
  this_figure_of_merit = get_figure_of_merit(curdev);

  /*
   * Now look for the last interface with an figure of merit
   * less than or equal to the new interface's figure of merit.
   *
   * We start with "prevdev" being NULL, meaning we're before
   * the first element in the list.
   */
  prevdev = NULL;
  for (;;) {
    /*
     * Get the interface after this one.
     */
    if (prevdev == NULL) {
      /*
       * The next element is the first element.
       */
      nextdev = devlistp->beginning;
    } else
      nextdev = prevdev->next;

    /*
     * Are we at the end of the list?
     */
    if (nextdev == NULL) {
      /*
       * Yes - we have to put the new entry after "prevdev".
       */
      break;
    }

    /*
     * Is the new interface's figure of merit less
     * than the next interface's figure of merit,
     * meaning that the new interface is better
     * than the next interface?
     */
    nextdev_figure_of_merit = get_figure_of_merit(nextdev);
    if (this_figure_of_merit < nextdev_figure_of_merit) {
      /*
       * Yes - we should put the new entry
       * before "nextdev", i.e. after "prevdev".
       */
      break;
    }

    prevdev = nextdev;
  }

  /*
   * Insert before "nextdev".
   */
  curdev->next = nextdev;

  /*
   * Insert after "prevdev" - unless "prevdev" is null,
   * in which case this is the first interface.
   */
  if (prevdev == NULL) {
    /*
     * This is the first interface.  Make it
     * the first element in the list of devices.
     */
    devlistp->beginning = curdev;
  } else
    prevdev->next = curdev;
  return (curdev);
}

/*
 * Free a list of interfaces.
 */
void
pcap_freealldevs(pcap_if_t *alldevs)
{
  pcap_if_t *curdev, *nextdev;
  pcap_addr_t *curaddr, *nextaddr;

  for (curdev = alldevs; curdev != NULL; curdev = nextdev) {
    nextdev = curdev->next;

    /*
     * Free all addresses.
     */
    for (curaddr = curdev->addresses; curaddr != NULL; curaddr = nextaddr) {
      nextaddr = curaddr->next;
      if (curaddr->addr)
        free(curaddr->addr);
      if (curaddr->netmask)
        free(curaddr->netmask);
      if (curaddr->broadaddr)
        free(curaddr->broadaddr);
      if (curaddr->dstaddr)
        free(curaddr->dstaddr);
      free(curaddr);
    }

    /*
     * Free the name string.
     */
    free(curdev->name);

    /*
     * Free the description string, if any.
     */
    if (curdev->description != NULL)
      free(curdev->description);

    /*
     * Free the interface.
     */
    free(curdev);
  }
}

/*
 * pcap-npf.c has its own pcap_lookupdev(), for compatibility reasons, as
 * it actually returns the names of all interfaces, with a NUL separator
 * between them; some callers may depend on that.
 *
 * MS-DOS has its own pcap_lookupdev(), but that might be useful only
 * as an optimization.
 *
 * In all other cases, we just use pcap_findalldevs() to get a list of
 * devices, and pick from that list.
 */
#if !defined(HAVE_PACKET32) && !defined(MSDOS)
/*
 * 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(char *errbuf)
{
  pcap_if_t *alldevs;
#ifdef _WIN32
  /*
   * Windows - use the same size as the old WinPcap 3.1 code.
   * XXX - this is probably bigger than it needs to be.
   */
  #define IF_NAMESIZE 8192
#else
  /*
   * UN*X - use the system's interface name size.
   * XXX - that might not be large enough for capture devices
   * that aren't regular network interfaces.
   */
  /* for old BSD systems, including bsdi3 */
  #ifndef IF_NAMESIZE
  #define IF_NAMESIZE IFNAMSIZ
  #endif
#endif
  static char device[IF_NAMESIZE + 1];
  char *ret;

  /*
   * We disable this in "new API" mode, because 1) in WinPcap/Npcap,
   * it may return UTF-16 strings, for backwards-compatibility
   * reasons, and we're also disabling the hack to make that work,
   * for not-going-past-the-end-of-a-string reasons, and 2) we
   * want its behavior to be consistent.
   *
   * In addition, it's not thread-safe, so we've marked it as
   * deprecated.
   */
  if (pcap_new_api) {
    snprintf(errbuf, PCAP_ERRBUF_SIZE,
        "pcap_lookupdev() is deprecated and is not supported in programs calling pcap_init()");
    return (NULL);
  }

  if (pcap_findalldevs(&alldevs, errbuf) == -1)
    return (NULL);

  if (alldevs == NULL || (alldevs->flags & PCAP_IF_LOOPBACK)) {
    /*
     * There are no devices on the list, or the first device
     * on the list is a loopback device, which means there
     * are no non-loopback devices on the list.  This means
     * we can't return any device.
     *
     * XXX - why not return a loopback device?  If we can't
     * capture on it, it won't be on the list, and if it's
     * on the list, there aren't any non-loopback devices,
     * so why not just supply it as the default device?
     */
    (void)pcap_strlcpy(errbuf, "no suitable device found",
        PCAP_ERRBUF_SIZE);
    ret = NULL;
  } else {
    /*
     * Return the name of the first device on the list.
     */
    (void)pcap_strlcpy(device, alldevs->name, sizeof(device));
    ret = device;
  }

  pcap_freealldevs(alldevs);
  return (ret);
}
#endif /* !defined(HAVE_PACKET32) && !defined(MSDOS) */

#if !defined(_WIN32) && !defined(MSDOS)
/*
 * We don't just fetch the entire list of devices, search for the
 * particular device, and use its first IPv4 address, as that's too
 * much work to get just one device's netmask.
 *
 * If we had an API to get attributes for a given device, we could
 * use that.
 */
int
pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp,
    char *errbuf)
{
  register int fd;
  register struct sockaddr_in *sin4;
  struct ifreq ifr;

  /*
   * The pseudo-device "any" listens on all interfaces and therefore
   * has the network address and -mask "0.0.0.0" therefore catching
   * all traffic. Using NULL for the interface is the same as "any".
   */
  if (!device || strcmp(device, "any") == 0
#ifdef HAVE_DAG_API
      || strstr(device, "dag") != NULL
#endif
#ifdef HAVE_SEPTEL_API
      || strstr(device, "septel") != NULL
#endif
#ifdef PCAP_SUPPORT_BT
      || strstr(device, "bluetooth") != NULL
#endif
#ifdef PCAP_SUPPORT_LINUX_USBMON
      || strstr(device, "usbmon") != NULL
#endif
#ifdef HAVE_SNF_API
      || strstr(device, "snf") != NULL
#endif
#ifdef PCAP_SUPPORT_NETMAP
      || strncmp(device, "netmap:", 7) == 0
      || strncmp(device, "vale", 4) == 0
#endif
#ifdef PCAP_SUPPORT_DPDK
      || strncmp(device, "dpdk:", 5) == 0
#endif
      ) {
    *netp = *maskp = 0;
    return 0;
  }

  fd = socket(AF_INET, SOCK_DGRAM, 0);
  if (fd < 0) {
    pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
        errno, "socket");
    return (-1);
  }
  memset(&ifr, 0, sizeof(ifr));
#ifdef linux
  /* XXX Work around Linux kernel bug */
  ifr.ifr_addr.sa_family = AF_INET;
#endif
  (void)pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
  if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
    if (errno == EADDRNOTAVAIL) {
      (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
          "%s: no IPv4 address assigned", device);
    } else {
      pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
          errno, "SIOCGIFADDR: %s", device);
    }
    (void)close(fd);
    return (-1);
  }
  sin4 = (struct sockaddr_in *)&ifr.ifr_addr;
  *netp = sin4->sin_addr.s_addr;
  memset(&ifr, 0, sizeof(ifr));
#ifdef linux
  /* XXX Work around Linux kernel bug */
  ifr.ifr_addr.sa_family = AF_INET;
#endif
  (void)pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
  if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
    pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
        errno, "SIOCGIFNETMASK: %s", device);
    (void)close(fd);
    return (-1);
  }
  (void)close(fd);
  *maskp = sin4->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)snprintf(errbuf, PCAP_ERRBUF_SIZE,
          "inet class for 0x%x unknown", *netp);
      return (-1);
    }
  }
  *netp &= *maskp;
  return (0);
}
#endif /* !defined(_WIN32) && !defined(MSDOS) */

#ifdef ENABLE_REMOTE
#include "pcap-rpcap.h"

/*
 * Extract a substring from a string.
 */
static char *
get_substring(const char *p, size_t len, char *ebuf)
{
  char *token;

  token = malloc(len + 1);
  if (token == NULL) {
    pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    return (NULL);
  }
  memcpy(token, p, len);
  token[len] = '\0';
  return (token);
}

/*
 * Parse a capture source that might be a URL.
 *
 * If the source is not a URL, *schemep, *userinfop, *hostp, and *portp
 * are set to NULL, *pathp is set to point to the source, and 0 is
 * returned.
 *
 * If source is a URL, and the URL refers to a local device (a special
 * case of rpcap:), *schemep, *userinfop, *hostp, and *portp are set
 * to NULL, *pathp is set to point to the device name, and 0 is returned.
 *
 * If source is a URL, and it's not a special case that refers to a local
 * device, and the parse succeeds:
 *
 *    *schemep is set to point to an allocated string containing the scheme;
 *
 *    if user information is present in the URL, *userinfop is set to point
 *    to an allocated string containing the user information, otherwise
 *    it's set to NULL;
 *
 *    if host information is present in the URL, *hostp is set to point
 *    to an allocated string containing the host information, otherwise
 *    it's set to NULL;
 *
 *    if a port number is present in the URL, *portp is set to point
 *    to an allocated string containing the port number, otherwise
 *    it's set to NULL;
 *
 *    *pathp is set to point to an allocated string containing the
 *    path;
 *
 * and 0 is returned.
 *
 * If the parse fails, ebuf is set to an error string, and -1 is returned.
 */
static int
pcap_parse_source(const char *source, char **schemep, char **userinfop,
    char **hostp, char **portp, char **pathp, char *ebuf)
{
  char *colonp;
  size_t scheme_len;
  char *scheme;
  const char *endp;
  size_t authority_len;
  char *authority;
  char *parsep, *atsignp, *bracketp;
  char *userinfo, *host, *port, *path;

  /*
   * Start out returning nothing.
   */
  *schemep = NULL;
  *userinfop = NULL;
  *hostp = NULL;
  *portp = NULL;
  *pathp = NULL;

  /*
   * RFC 3986 says:
   *
   *   URI         = scheme ":" hier-part [ "?" query ] [ "#" fragment ]
   *
   *   hier-part   = "//" authority path-abempty
   *               / path-absolute
   *               / path-rootless
   *               / path-empty
   *
   *   authority   = [ userinfo "@" ] host [ ":" port ]
   *
   *   userinfo    = *( unreserved / pct-encoded / sub-delims / ":" )
         *
         * Step 1: look for the ":" at the end of the scheme.
   * A colon in the source is *NOT* sufficient to indicate that
   * this is a URL, as interface names on some platforms might
   * include colons (e.g., I think some Solaris interfaces
   * might).
   */
  colonp = strchr(source, ':');
  if (colonp == NULL) {
    /*
     * The source is the device to open.
     * Return a NULL pointer for the scheme, user information,
     * host, and port, and return the device as the path.
     */
    *pathp = strdup(source);
    if (*pathp == NULL) {
      pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      return (-1);
    }
    return (0);
  }

  /*
   * All schemes must have "//" after them, i.e. we only support
   * hier-part   = "//" authority path-abempty, not
   * hier-part   = path-absolute
   * hier-part   = path-rootless
   * hier-part   = path-empty
   *
   * We need that in order to distinguish between a local device
   * name that happens to contain a colon and a URI.
   */
  if (strncmp(colonp + 1, "//", 2) != 0) {
    /*
     * The source is the device to open.
     * Return a NULL pointer for the scheme, user information,
     * host, and port, and return the device as the path.
     */
    *pathp = strdup(source);
    if (*pathp == NULL) {
      pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      return (-1);
    }
    return (0);
  }

  /*
   * XXX - check whether the purported scheme could be a scheme?
   */

  /*
   * OK, this looks like a URL.
   * Get the scheme.
   */
  scheme_len = colonp - source;
  scheme = malloc(scheme_len + 1);
  if (scheme == NULL) {
    pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    return (-1);
  }
  memcpy(scheme, source, scheme_len);
  scheme[scheme_len] = '\0';

  /*
   * Treat file: specially - take everything after file:// as
   * the pathname.
   */
  if (pcap_strcasecmp(scheme, "file") == 0) {
    *pathp = strdup(colonp + 3);
    if (*pathp == NULL) {
      pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      free(scheme);
      return (-1);
    }
    *schemep = scheme;
    return (0);
  }

  /*
   * The WinPcap documentation says you can specify a local
   * interface with "rpcap://{device}"; we special-case
   * that here.  If the scheme is "rpcap", and there are
   * no slashes past the "//", we just return the device.
   *
   * XXX - %-escaping?
   */
  if ((pcap_strcasecmp(scheme, "rpcap") == 0 ||
      pcap_strcasecmp(scheme, "rpcaps") == 0) &&
      strchr(colonp + 3, '/') == NULL) {
    /*
     * Local device.
     *
     * Return a NULL pointer for the scheme, user information,
     * host, and port, and return the device as the path.
     */
    free(scheme);
    *pathp = strdup(colonp + 3);
    if (*pathp == NULL) {
      pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
          errno, "malloc");
      return (-1);
    }
    return (0);
  }

  /*
   * OK, now start parsing the authority.
   * Get token, terminated with / or terminated at the end of
   * the string.
   */
  authority_len = strcspn(colonp + 3, "/");
  authority = get_substring(colonp + 3, authority_len, ebuf);
  if (authority == NULL) {
    /*
     * Error.
     */
    free(scheme);
    return (-1);
  }
  endp = colonp + 3 + authority_len;

  /*
   * Now carve the authority field into its components.
   */
  parsep = authority;

  /*
   * Is there a userinfo field?
   */
  atsignp = strchr(parsep, '@');
  if (atsignp != NULL) {
    /*
     * Yes.
     */
    size_t userinfo_len;

    userinfo_len = atsignp - parsep;
    userinfo = get_substring(parsep, userinfo_len, ebuf);
    if (userinfo == NULL) {
      /*
       * Error.
       */
      free(authority);
      free(scheme);
      return (-1);
    }
    parsep = atsignp + 1;
  } else {
    /*
     * No.
     */
    userinfo = NULL;
  }

  /*
   * Is there a host field?
   */
  if (*parsep == '\0') {
    /*
     * No; there's no host field or port field.
     */
    host = NULL;
    port = NULL;
  } else {
    /*
     * Yes.
     */
    size_t host_len;

    /*
     * Is it an IP-literal?
     */
    if (*parsep == '[') {
      /*
       * Yes.
       * Treat verything up to the closing square
       * bracket as the IP-Literal; we don't worry
       * about whether it's a valid IPv6address or
       * IPvFuture (or an IPv4address, for that
       * matter, just in case we get handed a
       * URL with an IPv4 IP-Literal, of the sort
       * that pcap_createsrcstr() used to generate,
       * and that pcap_parsesrcstr(), in the original
       * WinPcap code, accepted).
       */
      bracketp = strchr(parsep, ']');
      if (bracketp == NULL) {
        /*
         * There's no closing square bracket.
         */
        snprintf(ebuf, PCAP_ERRBUF_SIZE,
            "IP-literal in URL doesn't end with ]");
        free(userinfo);
        free(authority);
        free(scheme);
        return (-1);
      }
      if (*(bracketp + 1) != '\0' &&
          *(bracketp + 1) != ':') {
        /*
         * There's extra crud after the
         * closing square bracketn.
         */
        snprintf(ebuf, PCAP_ERRBUF_SIZE,
            "Extra text after IP-literal in URL");
        free(userinfo);
        free(authority);
        free(scheme);
        return (-1);
      }
      host_len = (bracketp - 1) - parsep;
      host = get_substring(parsep + 1, host_len, ebuf);
      if (host == NULL) {
        /*
         * Error.
         */
        free(userinfo);
        free(authority);
        free(scheme);
        return (-1);
      }
      parsep = bracketp + 1;
    } else {
      /*
       * No.
       * Treat everything up to a : or the end of
       * the string as the host.
       */
      host_len = strcspn(parsep, ":");
      host = get_substring(parsep, host_len, ebuf);
      if (host == NULL) {
        /*
         * Error.
         */
        free(userinfo);
        free(authority);
        free(scheme);
        return (-1);
      }
      parsep = parsep + host_len;
    }

    /*
     * Is there a port field?
     */
    if (*parsep == ':') {
      /*
       * Yes.  It's the rest of the authority field.
       */
      size_t port_len;

      parsep++;
      port_len = strlen(parsep);
      port = get_substring(parsep, port_len, ebuf);
      if (port == NULL) {
        /*
         * Error.
         */
        free(host);
        free(userinfo);
        free(authority);
        free(scheme);
        return (-1);
      }
    } else {
      /*
       * No.
       */
      port = NULL;
    }
  }
  free(authority);

  /*
   * Everything else is the path.  Strip off the leading /.
   */
  if (*endp == '\0')
    path = strdup("");
  else
    path = strdup(endp + 1);
  if (path == NULL) {
    pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    free(port);
    free(host);
    free(userinfo);
    free(scheme);
    return (-1);
  }
  *schemep = scheme;
  *userinfop = userinfo;
  *hostp = host;
  *portp = port;
  *pathp = path;
  return (0);
}

int
pcap_createsrcstr_ex(char *source, int type, const char *userinfo, const char *host,
    const char *port, const char *name, unsigned char uses_ssl, char *errbuf)
{
  switch (type) {

  case PCAP_SRC_FILE:
    pcap_strlcpy(source, PCAP_SRC_FILE_STRING, PCAP_BUF_SIZE);
    if (name != NULL && *name != '\0') {
      pcap_strlcat(source, name, PCAP_BUF_SIZE);
      return (0);
    } else {
      snprintf(errbuf, PCAP_ERRBUF_SIZE,
          "The file name cannot be NULL.");
      return (-1);
    }

  case PCAP_SRC_IFREMOTE:
    pcap_strlcpy(source,
        (uses_ssl ? "rpcaps://" : PCAP_SRC_IF_STRING),
        PCAP_BUF_SIZE);
    if (host != NULL && *host != '\0') {
      if (userinfo != NULL && *userinfo != '\0') {
        pcap_strlcat(source, userinfo, PCAP_BUF_SIZE);
        pcap_strlcat(source, "@", PCAP_BUF_SIZE);
      }

      if (strchr(host, ':') != NULL) {
        /*
         * The host name contains a colon, so it's
         * probably an IPv6 address, and needs to
         * be included in square brackets.
         */
        pcap_strlcat(source, "[", PCAP_BUF_SIZE);
        pcap_strlcat(source, host, PCAP_BUF_SIZE);
        pcap_strlcat(source, "]", PCAP_BUF_SIZE);
      } else
        pcap_strlcat(source, host, PCAP_BUF_SIZE);

      if (port != NULL && *port != '\0') {
        pcap_strlcat(source, ":", PCAP_BUF_SIZE);
        pcap_strlcat(source, port, PCAP_BUF_SIZE);
      }

      pcap_strlcat(source, "/", PCAP_BUF_SIZE);
    } else {
      snprintf(errbuf, PCAP_ERRBUF_SIZE,
          "The host name cannot be NULL.");
      return (-1);
    }

    if (name != NULL && *name != '\0')
      pcap_strlcat(source, name, PCAP_BUF_SIZE);

    return (0);

  case PCAP_SRC_IFLOCAL:
    pcap_strlcpy(source, PCAP_SRC_IF_STRING, PCAP_BUF_SIZE);

    if (name != NULL && *name != '\0')
      pcap_strlcat(source, name, PCAP_BUF_SIZE);

    return (0);

  default:
    snprintf(errbuf, PCAP_ERRBUF_SIZE,
        "The interface type is not valid.");
    return (-1);
  }
}


int
pcap_createsrcstr(char *source, int type, const char *host, const char *port,
    const char *name, char *errbuf)
{
  return (pcap_createsrcstr_ex(source, type, NULL, host, port, name, 0, errbuf));
}

int
pcap_parsesrcstr_ex(const char *source, int *type, char *userinfo, char *host,
    char *port, char *name, unsigned char *uses_ssl, char *errbuf)
{
  char *scheme, *tmpuserinfo, *tmphost, *tmpport, *tmppath;

  /* Initialization stuff */
  if (userinfo)
    *userinfo = '\0';
  if (host)
    *host = '\0';
  if (port)
    *port = '\0';
  if (name)
    *name = '\0';
  if (uses_ssl)
    *uses_ssl = 0;

  /* Parse the source string */
  if (pcap_parse_source(source, &scheme, &tmpuserinfo, &tmphost,
      &tmpport, &tmppath, errbuf) == -1) {
    /*
     * Fail.
     */
    return (-1);
  }

  if (scheme == NULL) {
    /*
     * Local device.
     */
    if (name && tmppath)
      pcap_strlcpy(name, tmppath, PCAP_BUF_SIZE);
    if (type)
      *type = PCAP_SRC_IFLOCAL;
    free(tmppath);
    free(tmpport);
    free(tmphost);
    free(tmpuserinfo);
    return (0);
  }

  int is_rpcap = 0;
  if (strcmp(scheme, "rpcaps") == 0) {
    is_rpcap = 1;
    if (uses_ssl) *uses_ssl = 1;
  } else if (strcmp(scheme, "rpcap") == 0) {
    is_rpcap = 1;
  }

  if (is_rpcap) {
    /*
     * rpcap[s]://
     *
     * pcap_parse_source() has already handled the case of
     * rpcap[s]://device
     */
    if (userinfo && tmpuserinfo)
      pcap_strlcpy(userinfo, tmpuserinfo, PCAP_BUF_SIZE);
    if (host && tmphost)
      pcap_strlcpy(host, tmphost, PCAP_BUF_SIZE);
    if (port && tmpport)
      pcap_strlcpy(port, tmpport, PCAP_BUF_SIZE);
    if (name && tmppath)
      pcap_strlcpy(name, tmppath, PCAP_BUF_SIZE);
    if (type)
      *type = PCAP_SRC_IFREMOTE;
    free(tmppath);
    free(tmpport);
    free(tmphost);
    free(tmpuserinfo);
    free(scheme);
    return (0);
  }

  if (strcmp(scheme, "file") == 0) {
    /*
     * file://
     */
    if (name && tmppath)
      pcap_strlcpy(name, tmppath, PCAP_BUF_SIZE);
    if (type)
      *type = PCAP_SRC_FILE;
    free(tmppath);
    free(tmpport);
    free(tmphost);
    free(tmpuserinfo);
    free(scheme);
    return (0);
  }

  /*
   * Neither rpcap: nor file:; just treat the entire string
   * as a local device.
   */
  if (name)
    pcap_strlcpy(name, source, PCAP_BUF_SIZE);
  if (type)
    *type = PCAP_SRC_IFLOCAL;
  free(tmppath);
  free(tmpport);
  free(tmphost);
  free(tmpuserinfo);
  free(scheme);
  return (0);
}

int
pcap_parsesrcstr(const char *source, int *type, char *host, char *port,
    char *name, char *errbuf)
{
  return (pcap_parsesrcstr_ex(source, type, NULL, host, port, name, NULL, errbuf));
}
#endif

pcap_t *
pcap_create(const char *device, char *errbuf)
{
  size_t i;
  int is_theirs;
  pcap_t *p;
  char *device_str;

  /*
   * A null device name is equivalent to the "any" device -
   * which might not be supported on this platform, but
   * this means that you'll get a "not supported" error
   * rather than, say, a crash when we try to dereference
   * the null pointer.
   */
  if (device == NULL)
    device_str = strdup("any");
  else {
#ifdef _WIN32
    /*
     * On Windows, for backwards compatibility reasons,
     * pcap_lookupdev() returns a pointer to a sequence of
     * pairs of UTF-16LE device names and local code page
     * description strings.
     *
     * This means that if a program uses pcap_lookupdev()
     * to get a default device, and hands that to an API
     * that opens devices, we'll get handed a UTF-16LE
     * string, not a string in the local code page.
     *
     * To work around that, we check whether the string
     * looks as if it might be a UTF-16LE string and, if
     * so, convert it back to the local code page's
     * extended ASCII.
     *
     * We disable that check in "new API" mode, because:
     *
     *   1) You *cannot* reliably detect whether a
     *   string is UTF-16LE or not; "a" could either
     *   be a one-character ASCII string or the first
     *   character of a UTF-16LE string.
     *
     *   2) Doing that test can run past the end of
     *   the string, if it's a 1-character ASCII
     *   string
     *
     * This particular version of this heuristic dates
     * back to WinPcap 4.1.1; PacketOpenAdapter() does
     * uses the same heuristic, with the exact same
     * vulnerability.
     *
     * That's why we disable this in "new API" mode.
     * We keep it around in legacy mode for backwards
     * compatibility.
     */
    if (!pcap_new_api && device[0] != '\0' && device[1] == '\0') {
      size_t length;

      length = wcslen((wchar_t *)device);
      device_str = (char *)malloc(length + 1);
      if (device_str == NULL) {
        pcap_fmt_errmsg_for_errno(errbuf,
            PCAP_ERRBUF_SIZE, errno,
            "malloc");
        return (NULL);
      }

      snprintf(device_str, length + 1, "%ws",
          (const wchar_t *)device);
    } else
#endif
      device_str = strdup(device);
  }
  if (device_str == NULL) {
    pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    return (NULL);
  }

  /*
   * Try each of the non-local-network-interface capture
   * source types until we find one that works for this
   * device or run out of types.
   */
  for (i = 0; capture_source_types[i].create_op != NULL; i++) {
    is_theirs = 0;
    p = capture_source_types[i].create_op(device_str, errbuf,
        &is_theirs);
    if (is_theirs) {
      /*
       * The device name refers to a device of the
       * type in question; either it succeeded,
       * in which case p refers to a pcap_t to
       * later activate for the device, or it
       * failed, in which case p is null and we
       * should return that to report the failure
       * to create.
       */
      if (p == NULL) {
        /*
         * We assume the caller filled in errbuf.
         */
        free(device_str);
        return (NULL);
      }
      p->opt.device = device_str;
      return (p);
    }
  }

  /*
   * OK, try it as a regular network interface.
   */
  p = pcap_create_interface(device_str, errbuf);
  if (p == NULL) {
    /*
     * We assume the caller filled in errbuf.
     */
    free(device_str);
    return (NULL);
  }
  p->opt.device = device_str;
  return (p);
}

/*
 * Set nonblocking mode on an unactivated pcap_t; this sets a flag
 * checked by pcap_activate(), which sets the mode after calling
 * the activate routine.
 */
static int
pcap_setnonblock_unactivated(pcap_t *p, int nonblock)
{
  p->opt.nonblock = nonblock;
  return (0);
}

static void
initialize_ops(pcap_t *p)
{
  /*
   * Set operation pointers for operations that only work on
   * an activated pcap_t to point to a routine that returns
   * a "this isn't activated" error.
   */
  p->read_op = pcap_read_not_initialized;
  p->inject_op = pcap_inject_not_initialized;
  p->setfilter_op = pcap_setfilter_not_initialized;
  p->setdirection_op = pcap_setdirection_not_initialized;
  p->set_datalink_op = pcap_set_datalink_not_initialized;
  p->getnonblock_op = pcap_getnonblock_not_initialized;
  p->stats_op = pcap_stats_not_initialized;
#ifdef _WIN32
  p->stats_ex_op = pcap_stats_ex_not_initialized;
  p->setbuff_op = pcap_setbuff_not_initialized;
  p->setmode_op = pcap_setmode_not_initialized;
  p->setmintocopy_op = pcap_setmintocopy_not_initialized;
  p->getevent_op = pcap_getevent_not_initialized;
  p->oid_get_request_op = pcap_oid_get_request_not_initialized;
  p->oid_set_request_op = pcap_oid_set_request_not_initialized;
  p->sendqueue_transmit_op = pcap_sendqueue_transmit_not_initialized;
  p->setuserbuffer_op = pcap_setuserbuffer_not_initialized;
  p->live_dump_op = pcap_live_dump_not_initialized;
  p->live_dump_ended_op = pcap_live_dump_ended_not_initialized;
  p->get_airpcap_handle_op = pcap_get_airpcap_handle_not_initialized;
#endif

  /*
   * Default cleanup operation - implementations can override
   * this, but should call pcap_cleanup_live_common() after
   * doing their own additional cleanup.
   */
  p->cleanup_op = pcap_cleanup_live_common;

  /*
   * In most cases, the standard one-shot callback can
   * be used for pcap_next()/pcap_next_ex().
   */
  p->oneshot_callback = pcap_oneshot;

  /*
   * Default breakloop operation - implementations can override
   * this, but should call pcap_breakloop_common() before doing
   * their own logic.
   */
  p->breakloop_op = pcap_breakloop_common;
}

static pcap_t *
pcap_alloc_pcap_t(char *ebuf, size_t total_size, size_t private_offset)
{
  char *chunk;
  pcap_t *p;

  /*
   * total_size is the size of a structure containing a pcap_t
   * followed by a private structure.
   */
  chunk = calloc(total_size, 1);
  if (chunk == NULL) {
    pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
        errno, "malloc");
    return (NULL);
  }

  /*
   * Get a pointer to the pcap_t at the beginning.
   */
  p = (pcap_t *)chunk;

#ifdef _WIN32
  p->handle = INVALID_HANDLE_VALUE; /* not opened yet */
#else /* _WIN32 */
  p->fd = -1; /* not opened yet */
#ifndef MSDOS
  p->selectable_fd = -1;
  p->required_select_timeout = NULL;
#endif /* MSDOS */
#endif /* _WIN32 */

  /*
   * private_offset is the offset, in bytes, of the private
   * data from the beginning of the structure.
   *
   * Set the pointer to the private data; that's private_offset
   * bytes past the pcap_t.
   */
  p->priv = (void *)(chunk + private_offset);

  return (p);
}

pcap_t *
pcap_create_common(char *ebuf, size_t total_size, size_t private_offset)
{
  pcap_t *p;

  p = pcap_alloc_pcap_t(ebuf, total_size, private_offset);
  if (p == NULL)
    return (NULL);

  /*
   * Default to "can't set rfmon mode"; if it's supported by
   * a platform, the create routine that called us can set
   * the op to its routine to check whether a particular
   * device supports it.
   */
  p->can_set_rfmon_op = pcap_cant_set_rfmon;

  /*
   * If pcap_setnonblock() is called on a not-yet-activated
   * pcap_t, default to setting a flag and turning
   * on non-blocking mode when activated.
   */
  p->setnonblock_op = pcap_setnonblock_unactivated;

  initialize_ops(p);

  /* put in some defaults*/
  p->snapshot = 0;    /* max packet size unspecified */
  p->opt.timeout = 0;   /* no timeout specified */
  p->opt.buffer_size = 0;   /* use the platform's default */
  p->opt.promisc = 0;
  p->opt.rfmon = 0;
  p->opt.immediate = 0;
  p->opt.tstamp_type = -1;  /* default to not setting time stamp type */
  p->opt.tstamp_precision = PCAP_TSTAMP_PRECISION_MICRO;
  /*
   * Platform-dependent options.
   */
#ifdef __linux__
  p->opt.protocol = 0;
#endif
#ifdef _WIN32
  p->opt.nocapture_local = 0;
#endif

  /*
   * Start out with no BPF code generation flags set.
   */
  p->bpf_codegen_flags = 0;

  return (p);
}

int
pcap_check_activated(pcap_t *p)
{
  if (p->activated) {
    snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "can't perform "
      " operation on activated capture");
    return (-1);
  }
  return (0);
}

int
pcap_set_snaplen(pcap_t *p, int snaplen)
{
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  p->snapshot = snaplen;
  return (0);
}

int
pcap_set_promisc(pcap_t *p, int promisc)
{
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  p->opt.promisc = promisc;
  return (0);
}

int
pcap_set_rfmon(pcap_t *p, int rfmon)
{
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  p->opt.rfmon = rfmon;
  return (0);
}

int
pcap_set_timeout(pcap_t *p, int timeout_ms)
{
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  p->opt.timeout = timeout_ms;
  return (0);
}

int
pcap_set_tstamp_type(pcap_t *p, int tstamp_type)
{
  int i;

  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);

  /*
   * The argument should have been u_int, but that's too late
   * to change now - it's an API.
   */
  if (tstamp_type < 0)
    return (PCAP_WARNING_TSTAMP_TYPE_NOTSUP);

  /*
   * If p->tstamp_type_count is 0, we only support PCAP_TSTAMP_HOST;
   * the default time stamp type is PCAP_TSTAMP_HOST.
   */
  if (p->tstamp_type_count == 0) {
    if (tstamp_type == PCAP_TSTAMP_HOST) {
      p->opt.tstamp_type = tstamp_type;
      return (0);
    }
  } else {
    /*
     * Check whether we claim to support this type of time stamp.
     */
    for (i = 0; i < p->tstamp_type_count; i++) {
      if (p->tstamp_type_list[i] == (u_int)tstamp_type) {
        /*
         * Yes.
         */
        p->opt.tstamp_type = tstamp_type;
        return (0);
      }
    }
  }

  /*
   * We don't support this type of time stamp.
   */
  return (PCAP_WARNING_TSTAMP_TYPE_NOTSUP);
}

int
pcap_set_immediate_mode(pcap_t *p, int immediate)
{
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  p->opt.immediate = immediate;
  return (0);
}

int
pcap_set_buffer_size(pcap_t *p, int buffer_size)
{
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  if (buffer_size <= 0) {
    /*
     * Silently ignore invalid values.
     */
    return (0);
  }
  p->opt.buffer_size = buffer_size;
  return (0);
}

int
pcap_set_tstamp_precision(pcap_t *p, int tstamp_precision)
{
  int i;

  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);

  /*
   * The argument should have been u_int, but that's too late
   * to change now - it's an API.
   */
  if (tstamp_precision < 0)
    return (PCAP_ERROR_TSTAMP_PRECISION_NOTSUP);

  /*
   * If p->tstamp_precision_count is 0, we only support setting
   * the time stamp precision to microsecond precision; every
   * pcap module *MUST* support microsecond precision, even if
   * it does so by converting the native precision to
   * microseconds.
   */
  if (p->tstamp_precision_count == 0) {
    if (tstamp_precision == PCAP_TSTAMP_PRECISION_MICRO) {
      p->opt.tstamp_precision = tstamp_precision;
      return (0);
    }
  } else {
    /*
     * Check whether we claim to support this precision of
     * time stamp.
     */
    for (i = 0; i < p->tstamp_precision_count; i++) {
      if (p->tstamp_precision_list[i] == (u_int)tstamp_precision) {
        /*
         * Yes.
         */
        p->opt.tstamp_precision = tstamp_precision;
        return (0);
      }
    }
  }

  /*
   * We don't support this time stamp precision.
   */
  return (PCAP_ERROR_TSTAMP_PRECISION_NOTSUP);
}

int
pcap_get_tstamp_precision(pcap_t *p)
{
        return (p->opt.tstamp_precision);
}

int
pcap_activate(pcap_t *p)
{
  int status;

  /*
   * Catch attempts to re-activate an already-activated
   * pcap_t; this should, for example, catch code that
   * calls pcap_open_live() followed by pcap_activate(),
   * as some code that showed up in a Stack Exchange
   * question did.
   */
  if (pcap_check_activated(p))
    return (PCAP_ERROR_ACTIVATED);
  status = p->activate_op(p);
  if (status >= 0) {
    /*
     * If somebody requested non-blocking mode before
     * calling pcap_activate(), turn it on now.
     */
    if (p->opt.nonblock) {
      status = p->setnonblock_op(p, 1);
      if (status < 0) {
        /*
         * Failed.  Undo everything done by
         * the activate operation.
         */
        p->cleanup_op(p);
        initialize_ops(p);
        return (status);
      }
    }
    p->activated = 1;
  } else {
    if (p->errbuf[0] == '\0') {
      /*
       * No error message supplied by the activate routine;
       * for the benefit of programs that don't specially
       * handle errors other than PCAP_ERROR, return the
       * error message corresponding to the status.
       */
      snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s",
          pcap_statustostr(status));
    }

    /*
     * Undo any operation pointer setting, etc. done by
     * the activate operation.
     */
    initialize_ops(p);
  }
  return (status);
}

pcap_t *
pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, char *errbuf)
{
  pcap_t *p;
  int status;
#ifdef ENABLE_REMOTE
  char host[PCAP_BUF_SIZE + 1];
  char port[PCAP_BUF_SIZE + 1];
  char name[PCAP_BUF_SIZE + 1];
  int srctype;

  /*
   * A null device name is equivalent to the "any" device -
   * which might not be supported on this platform, but
   * this means that you'll get a "not supported" error
   * rather than, say, a crash when we try to dereference
   * the null pointer.
   */
  if (device == NULL)
    device = "any";

  /*
   * Retrofit - we have to make older applications compatible with
   * remote capture.
   * So we're calling pcap_open_remote() from here; this is a very
   * dirty hack.
   * Obviously, we cannot exploit all the new features; for instance,
   * we cannot send authentication, we cannot use a UDP data connection,
   * and so on.
   */
  if (pcap_parsesrcstr(device, &srctype, host, port, name, errbuf))
    return (NULL);

  if (srctype == PCAP_SRC_IFREMOTE) {
    /*
     * Although we already have host, port and iface, we prefer
     * to pass only 'device' to pcap_open_rpcap(), so that it has
     * to call pcap_parsesrcstr() again.
     * This is less optimized, but much clearer.
     */
    return (pcap_open_rpcap(device, snaplen,
        promisc ? PCAP_OPENFLAG_PROMISCUOUS : 0, to_ms,
        NULL, errbuf));
  }
  if (srctype == PCAP_SRC_FILE) {
    snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown URL scheme \"file\"");
    return (NULL);
  }
  if (srctype == PCAP_SRC_IFLOCAL) {
    /*
     * If it starts with rpcap://, that refers to a local device
     * (no host part in the URL). Remove the rpcap://, and
     * fall through to the regular open path.
     */
    if (strncmp(device, PCAP_SRC_IF_STRING, strlen(PCAP_SRC_IF_STRING)) == 0) {
      size_t len = strlen(device) - strlen(PCAP_SRC_IF_STRING) + 1;

      if (len > 0)
        device += strlen(PCAP_SRC_IF_STRING);
    }
  }
#endif  /* ENABLE_REMOTE */

  p = pcap_create(device, errbuf);
  if (p == NULL)
    return (NULL);
  status = pcap_set_snaplen(p, snaplen);
  if (status < 0)
    goto fail;
  status = pcap_set_promisc(p, promisc);
  if (status < 0)
    goto fail;
  status = pcap_set_timeout(p, to_ms);
  if (status < 0)
    goto fail;
  /*
   * Mark this as opened with pcap_open_live(), so that, for
   * example, we show the full list of DLT_ values, rather
   * than just the ones that are compatible with capturing
   * when not in monitor mode.  That allows existing applications
   * to work the way they used to work, but allows new applications
   * that know about the new open API to, for example, find out the
   * DLT_ values that they can select without changing whether
   * the adapter is in monitor mode or not.
   */
  p->oldstyle = 1;
  status = pcap_activate(p);
  if (status < 0)
    goto fail;
  return (p);
fail:
  if (status == PCAP_ERROR) {
    /*
     * Another buffer is a bit cumbersome, but it avoids
     * -Wformat-truncation.
     */
    char trimbuf[PCAP_ERRBUF_SIZE - 5]; /* 2 bytes shorter */

    pcap_strlcpy(trimbuf, p->errbuf, sizeof(trimbuf));
    snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %.*s", device,
        PCAP_ERRBUF_SIZE - 3, trimbuf);
  } else if (status == PCAP_ERROR_NO_SUCH_DEVICE ||
      status == PCAP_ERROR_PERM_DENIED ||
      status == PCAP_ERROR_PROMISC_PERM_DENIED) {
    /*
     * Only show the additional message if it's not
     * empty.
     */
    if (p->errbuf[0] != '\0') {
      /*
       * Idem.
       */
      char trimbuf[PCAP_ERRBUF_SIZE - 8]; /* 2 bytes shorter */

      pcap_strlcpy(trimbuf, p->errbuf, sizeof(trimbuf));
      snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s (%.*s)",
          device, pcap_statustostr(status),
          PCAP_ERRBUF_SIZE - 6, trimbuf);
    } else {
      snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
          device, pcap_statustostr(status));
    }
  } else {
    snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", device,
        pcap_statustostr(status));
  }
  pcap_close(p);
  return (NULL);
}

pcap_t *
pcap_open_offline_common(char *ebuf, size_t total_size, size_t private_offset)
{
  pcap_t *p;

  p = pcap_alloc_pcap_t(ebuf, total_size, private_offset);
  if (p == NULL)
    return (NULL);

  p->opt.tstamp_precision = PCAP_TSTAMP_PRECISION_MICRO;

  return (p);
}

int
pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
  return (p->read_op(p, cnt, callback, user));
}

int
pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
  register int n;

  for (;;) {
    if (p->rfile != NULL) {
      /*
       * 0 means EOF, so don't loop if we get 0.
       */
      n = pcap_offline_read(p, cnt, callback, user);
    } else {
      /*
       * XXX keep reading until we get something
       * (or an error occurs)
       */
      do {
        n = p->read_op(p, cnt, callback, user);
      } while (n == 0);
    }
    if (n <= 0)
      return (n);
    if (!PACKET_COUNT_IS_UNLIMITED(cnt)) {
      cnt -= n;
      if (cnt <= 0)
        return (0);
    }
  }
}

/*
 * Force the loop in "pcap_read()" or "pcap_read_offline()" to terminate.
 */
void
pcap_breakloop(pcap_t *p)
{
  p->breakloop_op(p);
}

int
pcap_datalink(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->linktype);
}

int
pcap_datalink_ext(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->linktype_ext);
}

int
pcap_list_datalinks(pcap_t *p, int **dlt_buffer)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  if (p->dlt_count == 0) {
    /*
     * We couldn't fetch the list of DLTs, which means
     * this platform doesn't support changing the
     * DLT for an interface.  Return a list of DLTs
     * containing only the DLT this device supports.
     */
    *dlt_buffer = (int*)malloc(sizeof(**dlt_buffer));
    if (*dlt_buffer == NULL) {
      pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
          errno, "malloc");
      return (PCAP_ERROR);
    }
    **dlt_buffer = p->linktype;
    return (1);
  } else {
    *dlt_buffer = (int*)calloc(sizeof(**dlt_buffer), p->dlt_count);
    if (*dlt_buffer == NULL) {
      pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
          errno, "malloc");
      return (PCAP_ERROR);
    }
    (void)memcpy(*dlt_buffer, p->dlt_list,
        sizeof(**dlt_buffer) * p->dlt_count);
    return (p->dlt_count);
  }
}

/*
 * In Windows, you might have a library built with one version of the
 * C runtime library and an application built with another version of
 * the C runtime library, which means that the library might use one
 * version of malloc() and free() and the application might use another
 * version of malloc() and free().  If so, that means something
 * allocated by the library cannot be freed by the application, so we
 * need to have a pcap_free_datalinks() routine to free up the list
 * allocated by pcap_list_datalinks(), even though it's just a wrapper
 * around free().
 */
void
pcap_free_datalinks(int *dlt_list)
{
  free(dlt_list);
}

int
pcap_set_datalink(pcap_t *p, int dlt)
{
  int i;
  const char *dlt_name;

  if (dlt < 0)
    goto unsupported;

  if (p->dlt_count == 0 || p->set_datalink_op == NULL) {
    /*
     * We couldn't fetch the list of DLTs, or we don't
     * have a "set datalink" operation, which means
     * this platform doesn't support changing the
     * DLT for an interface.  Check whether the new
     * DLT is the one this interface supports.
     */
    if (p->linktype != dlt)
      goto unsupported;

    /*
     * It is, so there's nothing we need to do here.
     */
    return (0);
  }
  for (i = 0; i < p->dlt_count; i++)
    if (p->dlt_list[i] == (u_int)dlt)
      break;
  if (i >= p->dlt_count)
    goto unsupported;
  if (p->dlt_count == 2 && p->dlt_list[0] == DLT_EN10MB &&
      dlt == DLT_DOCSIS) {
    /*
     * This is presumably an Ethernet device, as the first
     * link-layer type it offers is DLT_EN10MB, and the only
     * other type it offers is DLT_DOCSIS.  That means that
     * we can't tell the driver to supply DOCSIS link-layer
     * headers - we're just pretending that's what we're
     * getting, as, presumably, we're capturing on a dedicated
     * link to a Cisco Cable Modem Termination System, and
     * it's putting raw DOCSIS frames on the wire inside low-level
     * Ethernet framing.
     */
    p->linktype = dlt;
    return (0);
  }
  if (p->set_datalink_op(p, dlt) == -1)
    return (-1);
  p->linktype = dlt;
  return (0);

unsupported:
  dlt_name = pcap_datalink_val_to_name(dlt);
  if (dlt_name != NULL) {
    (void) snprintf(p->errbuf, sizeof(p->errbuf),
        "%s is not one of the DLTs supported by this device",
        dlt_name);
  } else {
    (void) snprintf(p->errbuf, sizeof(p->errbuf),
        "DLT %d is not one of the DLTs supported by this device",
        dlt);
  }
  return (-1);
}

/*
 * This array is designed for mapping upper and lower case letter
 * together for a case independent comparison.  The mappings are
 * based upon ascii character sequences.
 */
static const u_char charmap[] = {
  (u_char)'\000', (u_char)'\001', (u_char)'\002', (u_char)'\003',
  (u_char)'\004', (u_char)'\005', (u_char)'\006', (u_char)'\007',
  (u_char)'\010', (u_char)'\011', (u_char)'\012', (u_char)'\013',
  (u_char)'\014', (u_char)'\015', (u_char)'\016', (u_char)'\017',
  (u_char)'\020', (u_char)'\021', (u_char)'\022', (u_char)'\023',
  (u_char)'\024', (u_char)'\025', (u_char)'\026', (u_char)'\027',
  (u_char)'\030', (u_char)'\031', (u_char)'\032', (u_char)'\033',
  (u_char)'\034', (u_char)'\035', (u_char)'\036', (u_char)'\037',
  (u_char)'\040', (u_char)'\041', (u_char)'\042', (u_char)'\043',
  (u_char)'\044', (u_char)'\045', (u_char)'\046', (u_char)'\047',
  (u_char)'\050', (u_char)'\051', (u_char)'\052', (u_char)'\053',
  (u_char)'\054', (u_char)'\055', (u_char)'\056', (u_char)'\057',
  (u_char)'\060', (u_char)'\061', (u_char)'\062', (u_char)'\063',
  (u_char)'\064', (u_char)'\065', (u_char)'\066', (u_char)'\067',
  (u_char)'\070', (u_char)'\071', (u_char)'\072', (u_char)'\073',
  (u_char)'\074', (u_char)'\075', (u_char)'\076', (u_char)'\077',
  (u_char)'\100', (u_char)'\141', (u_char)'\142', (u_char)'\143',
  (u_char)'\144', (u_char)'\145', (u_char)'\146', (u_char)'\147',
  (u_char)'\150', (u_char)'\151', (u_char)'\152', (u_char)'\153',
  (u_char)'\154', (u_char)'\155', (u_char)'\156', (u_char)'\157',
  (u_char)'\160', (u_char)'\161', (u_char)'\162', (u_char)'\163',
  (u_char)'\164', (u_char)'\165', (u_char)'\166', (u_char)'\167',
  (u_char)'\170', (u_char)'\171', (u_char)'\172', (u_char)'\133',
  (u_char)'\134', (u_char)'\135', (u_char)'\136', (u_char)'\137',
  (u_char)'\140', (u_char)'\141', (u_char)'\142', (u_char)'\143',
  (u_char)'\144', (u_char)'\145', (u_char)'\146', (u_char)'\147',
  (u_char)'\150', (u_char)'\151', (u_char)'\152', (u_char)'\153',
  (u_char)'\154', (u_char)'\155', (u_char)'\156', (u_char)'\157',
  (u_char)'\160', (u_char)'\161', (u_char)'\162', (u_char)'\163',
  (u_char)'\164', (u_char)'\165', (u_char)'\166', (u_char)'\167',
  (u_char)'\170', (u_char)'\171', (u_char)'\172', (u_char)'\173',
  (u_char)'\174', (u_char)'\175', (u_char)'\176', (u_char)'\177',
  (u_char)'\200', (u_char)'\201', (u_char)'\202', (u_char)'\203',
  (u_char)'\204', (u_char)'\205', (u_char)'\206', (u_char)'\207',
  (u_char)'\210', (u_char)'\211', (u_char)'\212', (u_char)'\213',
  (u_char)'\214', (u_char)'\215', (u_char)'\216', (u_char)'\217',
  (u_char)'\220', (u_char)'\221', (u_char)'\222', (u_char)'\223',
  (u_char)'\224', (u_char)'\225', (u_char)'\226', (u_char)'\227',
  (u_char)'\230', (u_char)'\231', (u_char)'\232', (u_char)'\233',
  (u_char)'\234', (u_char)'\235', (u_char)'\236', (u_char)'\237',
  (u_char)'\240', (u_char)'\241', (u_char)'\242', (u_char)'\243',
  (u_char)'\244', (u_char)'\245', (u_char)'\246', (u_char)'\247',
  (u_char)'\250', (u_char)'\251', (u_char)'\252', (u_char)'\253',
  (u_char)'\254', (u_char)'\255', (u_char)'\256', (u_char)'\257',
  (u_char)'\260', (u_char)'\261', (u_char)'\262', (u_char)'\263',
  (u_char)'\264', (u_char)'\265', (u_char)'\266', (u_char)'\267',
  (u_char)'\270', (u_char)'\271', (u_char)'\272', (u_char)'\273',
  (u_char)'\274', (u_char)'\275', (u_char)'\276', (u_char)'\277',
  (u_char)'\300', (u_char)'\341', (u_char)'\342', (u_char)'\343',
  (u_char)'\344', (u_char)'\345', (u_char)'\346', (u_char)'\347',
  (u_char)'\350', (u_char)'\351', (u_char)'\352', (u_char)'\353',
  (u_char)'\354', (u_char)'\355', (u_char)'\356', (u_char)'\357',
  (u_char)'\360', (u_char)'\361', (u_char)'\362', (u_char)'\363',
  (u_char)'\364', (u_char)'\365', (u_char)'\366', (u_char)'\367',
  (u_char)'\370', (u_char)'\371', (u_char)'\372', (u_char)'\333',
  (u_char)'\334', (u_char)'\335', (u_char)'\336', (u_char)'\337',
  (u_char)'\340', (u_char)'\341', (u_char)'\342', (u_char)'\343',
  (u_char)'\344', (u_char)'\345', (u_char)'\346', (u_char)'\347',
  (u_char)'\350', (u_char)'\351', (u_char)'\352', (u_char)'\353',
  (u_char)'\354', (u_char)'\355', (u_char)'\356', (u_char)'\357',
  (u_char)'\360', (u_char)'\361', (u_char)'\362', (u_char)'\363',
  (u_char)'\364', (u_char)'\365', (u_char)'\366', (u_char)'\367',
  (u_char)'\370', (u_char)'\371', (u_char)'\372', (u_char)'\373',
  (u_char)'\374', (u_char)'\375', (u_char)'\376', (u_char)'\377',
};

int
pcap_strcasecmp(const char *s1, const char *s2)
{
  register const u_char *cm = charmap,
        *us1 = (const u_char *)s1,
        *us2 = (const u_char *)s2;

  while (cm[*us1] == cm[*us2++])
    if (*us1++ == '\0')
      return(0);
  return (cm[*us1] - cm[*--us2]);
}

struct dlt_choice {
  const char *name;
  const char *description;
  int dlt;
};

#define DLT_CHOICE(code, description) { #code, description, DLT_ ## code }
#define DLT_CHOICE_SENTINEL { NULL, NULL, 0 }

static struct dlt_choice dlt_choices[] = {
  DLT_CHOICE(NULL, "BSD loopback"),
  DLT_CHOICE(EN10MB, "Ethernet"),
  DLT_CHOICE(IEEE802, "Token ring"),
  DLT_CHOICE(ARCNET, "BSD ARCNET"),
  DLT_CHOICE(SLIP, "SLIP"),
  DLT_CHOICE(PPP, "PPP"),
  DLT_CHOICE(FDDI, "FDDI"),
  DLT_CHOICE(ATM_RFC1483, "RFC 1483 LLC-encapsulated ATM"),
  DLT_CHOICE(RAW, "Raw IP"),
  DLT_CHOICE(SLIP_BSDOS, "BSD/OS SLIP"),
  DLT_CHOICE(PPP_BSDOS, "BSD/OS PPP"),
  DLT_CHOICE(ATM_CLIP, "Linux Classical IP over ATM"),
  DLT_CHOICE(PPP_SERIAL, "PPP over serial"),
  DLT_CHOICE(PPP_ETHER, "PPPoE"),
  DLT_CHOICE(SYMANTEC_FIREWALL, "Symantec Firewall"),
  DLT_CHOICE(C_HDLC, "Cisco HDLC"),
  DLT_CHOICE(IEEE802_11, "802.11"),
  DLT_CHOICE(FRELAY, "Frame Relay"),
  DLT_CHOICE(LOOP, "OpenBSD loopback"),
  DLT_CHOICE(ENC, "OpenBSD encapsulated IP"),
  DLT_CHOICE(LINUX_SLL, "Linux cooked v1"),
  DLT_CHOICE(LTALK, "Localtalk"),
  DLT_CHOICE(PFLOG, "OpenBSD pflog file"),
  DLT_CHOICE(PFSYNC, "Packet filter state syncing"),
  DLT_CHOICE(PRISM_HEADER, "802.11 plus Prism header"),
  DLT_CHOICE(IP_OVER_FC, "RFC 2625 IP-over-Fibre Channel"),
  DLT_CHOICE(SUNATM, "Sun raw ATM"),
  DLT_CHOICE(IEEE802_11_RADIO, "802.11 plus radiotap header"),
  DLT_CHOICE(ARCNET_LINUX, "Linux ARCNET"),
  DLT_CHOICE(JUNIPER_MLPPP, "Juniper Multi-Link PPP"),
  DLT_CHOICE(JUNIPER_MLFR, "Juniper Multi-Link Frame Relay"),
  DLT_CHOICE(JUNIPER_ES, "Juniper Encryption Services PIC"),
  DLT_CHOICE(JUNIPER_GGSN, "Juniper GGSN PIC"),
  DLT_CHOICE(JUNIPER_MFR, "Juniper FRF.16 Frame Relay"),
  DLT_CHOICE(JUNIPER_ATM2, "Juniper ATM2 PIC"),
  DLT_CHOICE(JUNIPER_SERVICES, "Juniper Advanced Services PIC"),
  DLT_CHOICE(JUNIPER_ATM1, "Juniper ATM1 PIC"),
  DLT_CHOICE(APPLE_IP_OVER_IEEE1394, "Apple IP-over-IEEE 1394"),
  DLT_CHOICE(MTP2_WITH_PHDR, "SS7 MTP2 with Pseudo-header"),
  DLT_CHOICE(MTP2, "SS7 MTP2"),
  DLT_CHOICE(MTP3, "SS7 MTP3"),
  DLT_CHOICE(SCCP, "SS7 SCCP"),
  DLT_CHOICE(DOCSIS, "DOCSIS"),
  DLT_CHOICE(LINUX_IRDA, "Linux IrDA"),
  DLT_CHOICE(IEEE802_11_RADIO_AVS, "802.11 plus AVS radio information header"),
  DLT_CHOICE(JUNIPER_MONITOR, "Juniper Passive Monitor PIC"),
  DLT_CHOICE(BACNET_MS_TP, "BACnet MS/TP"),
  DLT_CHOICE(PPP_PPPD, "PPP for pppd, with direction flag"),
  DLT_CHOICE(JUNIPER_PPPOE, "Juniper PPPoE"),
  DLT_CHOICE(JUNIPER_PPPOE_ATM, "Juniper PPPoE/ATM"),
  DLT_CHOICE(GPRS_LLC, "GPRS LLC"),
  DLT_CHOICE(GPF_T, "GPF-T"),
  DLT_CHOICE(GPF_F, "GPF-F"),
  DLT_CHOICE(JUNIPER_PIC_PEER, "Juniper PIC Peer"),
  DLT_CHOICE(ERF_ETH, "Ethernet with Endace ERF header"),
  DLT_CHOICE(ERF_POS, "Packet-over-SONET with Endace ERF header"),
  DLT_CHOICE(LINUX_LAPD, "Linux vISDN LAPD"),
  DLT_CHOICE(JUNIPER_ETHER, "Juniper Ethernet"),
  DLT_CHOICE(JUNIPER_PPP, "Juniper PPP"),
  DLT_CHOICE(JUNIPER_FRELAY, "Juniper Frame Relay"),
  DLT_CHOICE(JUNIPER_CHDLC, "Juniper C-HDLC"),
  DLT_CHOICE(MFR, "FRF.16 Frame Relay"),
  DLT_CHOICE(JUNIPER_VP, "Juniper Voice PIC"),
  DLT_CHOICE(A429, "Arinc 429"),
  DLT_CHOICE(A653_ICM, "Arinc 653 Interpartition Communication"),
  DLT_CHOICE(USB_FREEBSD, "USB with FreeBSD header"),
  DLT_CHOICE(BLUETOOTH_HCI_H4, "Bluetooth HCI UART transport layer"),
  DLT_CHOICE(IEEE802_16_MAC_CPS, "IEEE 802.16 MAC Common Part Sublayer"),
  DLT_CHOICE(USB_LINUX, "USB with Linux header"),
  DLT_CHOICE(CAN20B, "Controller Area Network (CAN) v. 2.0B"),
  DLT_CHOICE(IEEE802_15_4_LINUX, "IEEE 802.15.4 with Linux padding"),
  DLT_CHOICE(PPI, "Per-Packet Information"),
  DLT_CHOICE(IEEE802_16_MAC_CPS_RADIO, "IEEE 802.16 MAC Common Part Sublayer plus radiotap header"),
  DLT_CHOICE(JUNIPER_ISM, "Juniper Integrated Service Module"),
  DLT_CHOICE(IEEE802_15_4, "IEEE 802.15.4 with FCS"),
  DLT_CHOICE(SITA, "SITA pseudo-header"),
  DLT_CHOICE(ERF, "Endace ERF header"),
  DLT_CHOICE(RAIF1, "Ethernet with u10 Networks pseudo-header"),
  DLT_CHOICE(IPMB_KONTRON, "IPMB with Kontron pseudo-header"),
  DLT_CHOICE(JUNIPER_ST, "Juniper Secure Tunnel"),
  DLT_CHOICE(BLUETOOTH_HCI_H4_WITH_PHDR, "Bluetooth HCI UART transport layer plus pseudo-header"),
  DLT_CHOICE(AX25_KISS, "AX.25 with KISS header"),
  DLT_CHOICE(IPMB_LINUX, "IPMB with Linux/Pigeon Point pseudo-header"),
  DLT_CHOICE(IEEE802_15_4_NONASK_PHY, "IEEE 802.15.4 with non-ASK PHY data"),
  DLT_CHOICE(MPLS, "MPLS with label as link-layer header"),
  DLT_CHOICE(LINUX_EVDEV, "Linux evdev events"),
  DLT_CHOICE(USB_LINUX_MMAPPED, "USB with padded Linux header"),
  DLT_CHOICE(DECT, "DECT"),
  DLT_CHOICE(AOS, "AOS Space Data Link protocol"),
  DLT_CHOICE(WIHART, "WirelessHART"),
  DLT_CHOICE(FC_2, "Fibre Channel FC-2"),
  DLT_CHOICE(FC_2_WITH_FRAME_DELIMS, "Fibre Channel FC-2 with frame delimiters"),
  DLT_CHOICE(IPNET, "Solaris ipnet"),
  DLT_CHOICE(CAN_SOCKETCAN, "CAN-bus with SocketCAN headers"),
  DLT_CHOICE(IPV4, "Raw IPv4"),
  DLT_CHOICE(IPV6, "Raw IPv6"),
  DLT_CHOICE(IEEE802_15_4_NOFCS, "IEEE 802.15.4 without FCS"),
  DLT_CHOICE(DBUS, "D-Bus"),
  DLT_CHOICE(JUNIPER_VS, "Juniper Virtual Server"),
  DLT_CHOICE(JUNIPER_SRX_E2E, "Juniper SRX E2E"),
  DLT_CHOICE(JUNIPER_FIBRECHANNEL, "Juniper Fibre Channel"),
  DLT_CHOICE(DVB_CI, "DVB-CI"),
  DLT_CHOICE(MUX27010, "MUX27010"),
  DLT_CHOICE(STANAG_5066_D_PDU, "STANAG 5066 D_PDUs"),
  DLT_CHOICE(JUNIPER_ATM_CEMIC, "Juniper ATM CEMIC"),
  DLT_CHOICE(NFLOG, "Linux netfilter log messages"),
  DLT_CHOICE(NETANALYZER, "Ethernet with Hilscher netANALYZER pseudo-header"),
  DLT_CHOICE(NETANALYZER_TRANSPARENT, "Ethernet with Hilscher netANALYZER pseudo-header and with preamble and SFD"),
  DLT_CHOICE(IPOIB, "RFC 4391 IP-over-Infiniband"),
  DLT_CHOICE(MPEG_2_TS, "MPEG-2 transport stream"),
  DLT_CHOICE(NG40, "ng40 protocol tester Iub/Iur"),
  DLT_CHOICE(NFC_LLCP, "NFC LLCP PDUs with pseudo-header"),
  DLT_CHOICE(INFINIBAND, "InfiniBand"),
  DLT_CHOICE(SCTP, "SCTP"),
  DLT_CHOICE(USBPCAP, "USB with USBPcap header"),
  DLT_CHOICE(RTAC_SERIAL, "Schweitzer Engineering Laboratories RTAC packets"),
  DLT_CHOICE(BLUETOOTH_LE_LL, "Bluetooth Low Energy air interface"),
  DLT_CHOICE(NETLINK, "Linux netlink"),
  DLT_CHOICE(BLUETOOTH_LINUX_MONITOR, "Bluetooth Linux Monitor"),
  DLT_CHOICE(BLUETOOTH_BREDR_BB, "Bluetooth Basic Rate/Enhanced Data Rate baseband packets"),
  DLT_CHOICE(BLUETOOTH_LE_LL_WITH_PHDR, "Bluetooth Low Energy air interface with pseudo-header"),
  DLT_CHOICE(PROFIBUS_DL, "PROFIBUS data link layer"),
  DLT_CHOICE(PKTAP, "Apple DLT_PKTAP"),
  DLT_CHOICE(EPON, "Ethernet with 802.3 Clause 65 EPON preamble"),
  DLT_CHOICE(IPMI_HPM_2, "IPMI trace packets"),
  DLT_CHOICE(ZWAVE_R1_R2, "Z-Wave RF profile R1 and R2 packets"),
  DLT_CHOICE(ZWAVE_R3, "Z-Wave RF profile R3 packets"),
  DLT_CHOICE(WATTSTOPPER_DLM, "WattStopper Digital Lighting Management (DLM) and Legrand Nitoo Open protocol"),
  DLT_CHOICE(ISO_14443, "ISO 14443 messages"),
  DLT_CHOICE(RDS, "IEC 62106 Radio Data System groups"),
  DLT_CHOICE(USB_DARWIN, "USB with Darwin header"),
  DLT_CHOICE(OPENFLOW, "OpenBSD DLT_OPENFLOW"),
  DLT_CHOICE(SDLC, "IBM SDLC frames"),
  DLT_CHOICE(TI_LLN_SNIFFER, "TI LLN sniffer frames"),
  DLT_CHOICE(VSOCK, "Linux vsock"),
  DLT_CHOICE(NORDIC_BLE, "Nordic Semiconductor Bluetooth LE sniffer frames"),
  DLT_CHOICE(DOCSIS31_XRA31, "Excentis XRA-31 DOCSIS 3.1 RF sniffer frames"),
  DLT_CHOICE(ETHERNET_MPACKET, "802.3br mPackets"),
  DLT_CHOICE(DISPLAYPORT_AUX, "DisplayPort AUX channel monitoring data"),
  DLT_CHOICE(LINUX_SLL2, "Linux cooked v2"),
  DLT_CHOICE(OPENVIZSLA, "OpenVizsla USB"),
  DLT_CHOICE(EBHSCR, "Elektrobit High Speed Capture and Replay (EBHSCR)"),
  DLT_CHOICE(VPP_DISPATCH, "VPP graph dispatch tracer"),
  DLT_CHOICE(DSA_TAG_BRCM, "Broadcom tag"),
  DLT_CHOICE(DSA_TAG_BRCM_PREPEND, "Broadcom tag (prepended)"),
  DLT_CHOICE(IEEE802_15_4_TAP, "IEEE 802.15.4 with pseudo-header"),
  DLT_CHOICE(DSA_TAG_DSA, "Marvell DSA"),
  DLT_CHOICE(DSA_TAG_EDSA, "Marvell EDSA"),
  DLT_CHOICE(ELEE, "ELEE lawful intercept packets"),
  DLT_CHOICE(Z_WAVE_SERIAL, "Z-Wave serial frames between host and chip"),
  DLT_CHOICE(USB_2_0, "USB 2.0/1.1/1.0 as transmitted over the cable"),
  DLT_CHOICE(ATSC_ALP, "ATSC Link-Layer Protocol packets"),
  DLT_CHOICE(ETW, "Event Tracing for Windows messages"),
  DLT_CHOICE(NETANALYZER_NG, "Hilscher netANALYZER NG pseudo-footer"),
  DLT_CHOICE(ZBOSS_NCP, "ZBOSS NCP protocol with pseudo-header"),
  DLT_CHOICE(USB_2_0_LOW_SPEED, "Low-Speed USB 2.0/1.1/1.0 as transmitted over the cable"),
  DLT_CHOICE(USB_2_0_FULL_SPEED, "Full-Speed USB 2.0/1.1/1.0 as transmitted over the cable"),
  DLT_CHOICE(USB_2_0_HIGH_SPEED, "High-Speed USB 2.0 as transmitted over the cable"),
  DLT_CHOICE_SENTINEL
};

int
pcap_datalink_name_to_val(const char *name)
{
  int i;

  for (i = 0; dlt_choices[i].name != NULL; i++) {
    if (pcap_strcasecmp(dlt_choices[i].name, name) == 0)
      return (dlt_choices[i].dlt);
  }
  return (-1);
}

const char *
pcap_datalink_val_to_name(int dlt)
{
  int i;

  for (i = 0; dlt_choices[i].name != NULL; i++) {
    if (dlt_choices[i].dlt == dlt)
      return (dlt_choices[i].name);
  }
  return (NULL);
}

const char *
pcap_datalink_val_to_description(int dlt)
{
  int i;

  for (i = 0; dlt_choices[i].name != NULL; i++) {
    if (dlt_choices[i].dlt == dlt)
      return (dlt_choices[i].description);
  }
  return (NULL);
}

const char *
pcap_datalink_val_to_description_or_dlt(int dlt)
{
        static char unkbuf[40];
        const char *description;

        description = pcap_datalink_val_to_description(dlt);
        if (description != NULL) {
                return description;
        } else {
                (void)snprintf(unkbuf, sizeof(unkbuf), "DLT %d", dlt);
                return unkbuf;
        }
}

struct tstamp_type_choice {
  const char *name;
  const char *description;
  int type;
};

static struct tstamp_type_choice tstamp_type_choices[] = {
  { "host", "Host", PCAP_TSTAMP_HOST },
  { "host_lowprec", "Host, low precision", PCAP_TSTAMP_HOST_LOWPREC },
  { "host_hiprec", "Host, high precision", PCAP_TSTAMP_HOST_HIPREC },
  { "adapter", "Adapter", PCAP_TSTAMP_ADAPTER },
  { "adapter_unsynced", "Adapter, not synced with system time", PCAP_TSTAMP_ADAPTER_UNSYNCED },
  { "host_hiprec_unsynced", "Host, high precision, not synced with system time", PCAP_TSTAMP_HOST_HIPREC_UNSYNCED },
  { NULL, NULL, 0 }
};

int
pcap_tstamp_type_name_to_val(const char *name)
{
  int i;

  for (i = 0; tstamp_type_choices[i].name != NULL; i++) {
    if (pcap_strcasecmp(tstamp_type_choices[i].name, name) == 0)
      return (tstamp_type_choices[i].type);
  }
  return (PCAP_ERROR);
}

const char *
pcap_tstamp_type_val_to_name(int tstamp_type)
{
  int i;

  for (i = 0; tstamp_type_choices[i].name != NULL; i++) {
    if (tstamp_type_choices[i].type == tstamp_type)
      return (tstamp_type_choices[i].name);
  }
  return (NULL);
}

const char *
pcap_tstamp_type_val_to_description(int tstamp_type)
{
  int i;

  for (i = 0; tstamp_type_choices[i].name != NULL; i++) {
    if (tstamp_type_choices[i].type == tstamp_type)
      return (tstamp_type_choices[i].description);
  }
  return (NULL);
}

int
pcap_snapshot(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->snapshot);
}

int
pcap_is_swapped(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->swapped);
}

int
pcap_major_version(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->version_major);
}

int
pcap_minor_version(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->version_minor);
}

int
pcap_bufsize(pcap_t *p)
{
  if (!p->activated)
    return (PCAP_ERROR_NOT_ACTIVATED);
  return (p->bufsize);
}

FILE *
pcap_file(pcap_t *p)
{
  return (p->rfile);
}

#ifdef _WIN32
int
pcap_fileno(pcap_t *p)
{
  if (p->handle != INVALID_HANDLE_VALUE) {
    /*
     * This is a bogus and now-deprecated API; we
     * squelch the narrowing warning for the cast
     * from HANDLE to intptr_t.  If Windows programmmers
     * need to get at the HANDLE for a pcap_t, *if*
     * there is one, they should request such a
     * routine (and be prepared for it to return
     * INVALID_HANDLE_VALUE).
     */
DIAG_OFF_NARROWING
    return ((int)(intptr_t)p->handle);
DIAG_ON_NARROWING
  } else
    return (PCAP_ERROR);
}
#else /* _WIN32 */
int
pcap_fileno(pcap_t *p)
{
  return (p->fd);
}
#endif /* _WIN32 */

#if !defined(_WIN32) && !defined(MSDOS)
int
pcap_get_selectable_fd(pcap_t *p)
{
  return (p->selectable_fd);
}

const struct timeval *
pcap_get_required_select_timeout(pcap_t *p)
{
  return (p->required_select_timeout);
}
#endif

void
pcap_perror(pcap_t *p, const char *prefix)
{
  fprintf(stderr, "%s: %s\n", prefix, p->errbuf);
}

char *
pcap_geterr(pcap_t *p)
{
  return (p->errbuf);
}

int
pcap_getnonblock(pcap_t *p, char *errbuf)
{
  int ret;

  ret = p->getnonblock_op(p);
  if (ret == -1) {
    /*
     * The get nonblock operation sets p->errbuf; this
     * function *shouldn't* have had a separate errbuf
     * argument, as it didn't need one, but I goofed
     * when adding it.
     *
     * We copy the error message to errbuf, so callers
     * can find it in either place.
     */
    pcap_strlcpy(errbuf, p->errbuf, PCAP_ERRBUF_SIZE);
  }
  return (ret);
}

/*
 * Get the current non-blocking mode setting, under the assumption that
 * it's just the standard POSIX non-blocking flag.
 */
#if !defined(_WIN32) && !defined(MSDOS)
int
pcap_getnonblock_fd(pcap_t *p)
{
  int fdflags;

  fdflags = fcntl(p->fd, F_GETFL, 0);
  if (fdflags == -1) {
    pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
        errno, "F_GETFL");
    return (-1);
  }
  if (fdflags & O_NONBLOCK)
    return (1);
  else
    return (0);
}
#endif

int
pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf)
{
  int ret;

  ret = p->setnonblock_op(p, nonblock);
  if (ret == -1) {
    /*
     * The set nonblock operation sets p->errbuf; this
     * function *shouldn't* have had a separate errbuf
     * argument, as it didn't need one, but I goofed
     * when adding it.
     *
     * We copy the error message to errbuf, so callers
     * can find it in either place.
     */
    pcap_strlcpy(errbuf, p->errbuf, PCAP_ERRBUF_SIZE);
  }
  return (ret);
}

#if !defined(_WIN32) && !defined(MSDOS)
/*
 * Set non-blocking mode, under the assumption that it's just the
 * standard POSIX non-blocking flag.  (This can be called by the
 * per-platform non-blocking-mode routine if that routine also
 * needs to do some additional work.)
 */
int
pcap_setnonblock_fd(pcap_t *p, int nonblock)
{
  int fdflags;

  fdflags = fcntl(p->fd, F_GETFL, 0);
  if (fdflags == -1) {
    pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
        errno, "F_GETFL");
    return (-1);
  }
  if (nonblock)
    fdflags |= O_NONBLOCK;
  else
    fdflags &= ~O_NONBLOCK;
  if (fcntl(p->fd, F_SETFL, fdflags) == -1) {
    pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
        errno, "F_SETFL");
    return (-1);
  }
  return (0);
}
#endif

/*
 * Generate error strings for PCAP_ERROR_ and PCAP_WARNING_ values.
 */
const char *
pcap_statustostr(int errnum)
{
  static char ebuf[15+10+1];

  switch (errnum) {

  case PCAP_WARNING:
    return("Generic warning");

  case PCAP_WARNING_TSTAMP_TYPE_NOTSUP:
    return ("That type of time stamp is not supported by that device");

  case PCAP_WARNING_PROMISC_NOTSUP:
    return ("That device doesn't support promiscuous mode");

  case PCAP_ERROR:
    return("Generic error");

  case PCAP_ERROR_BREAK:
    return("Loop terminated by pcap_breakloop");

  case PCAP_ERROR_NOT_ACTIVATED:
    return("The pcap_t has not been activated");

  case PCAP_ERROR_ACTIVATED:
    return ("The setting can't be changed after the pcap_t is activated");

  case PCAP_ERROR_NO_SUCH_DEVICE:
    return ("No such device exists");

  case PCAP_ERROR_RFMON_NOTSUP:
    return ("That device doesn't support monitor mode");

  case PCAP_ERROR_NOT_RFMON:
    return ("That operation is supported only in monitor mode");

  case PCAP_ERROR_PERM_DENIED:
    return ("You don't have permission to perform this capture on that device");

  case PCAP_ERROR_IFACE_NOT_UP:
    return ("That device is not up");

  case PCAP_ERROR_CANTSET_TSTAMP_TYPE:
    return ("That device doesn't support setting the time stamp type");

  case PCAP_ERROR_PROMISC_PERM_DENIED:
    return ("You don't have permission to capture in promiscuous mode on that device");

  case PCAP_ERROR_TSTAMP_PRECISION_NOTSUP:
    return ("That device doesn't support that time stamp precision");
  }
  (void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum);
  return(ebuf);
}

/*
 * Not all systems have strerror().
 */
const char *
pcap_strerror(int errnum)
{
#ifdef HAVE_STRERROR
#ifdef _WIN32
  static char errbuf[PCAP_ERRBUF_SIZE];
  errno_t err = strerror_s(errbuf, PCAP_ERRBUF_SIZE, errnum);

  if (err != 0) /* err = 0 if successful */
    pcap_strlcpy(errbuf, "strerror_s() error", PCAP_ERRBUF_SIZE);
  return (errbuf);
#else
  return (strerror(errnum));
#endif /* _WIN32 */
#else
  extern int sys_nerr;
  extern const char *const sys_errlist[];
  static char errbuf[PCAP_ERRBUF_SIZE];

  if ((unsigned int)errnum < sys_nerr)
    return ((char *)sys_errlist[errnum]);
  (void)snprintf(errbuf, sizeof errbuf, "Unknown error: %d", errnum);
  return (errbuf);
#endif
}

int
pcap_setfilter(pcap_t *p, struct bpf_program *fp)
{
  return (p->setfilter_op(p, fp));
}

/*
 * Set direction flag, which controls whether we accept only incoming
 * packets, only outgoing packets, or both.
 * Note that, depending on the platform, some or all direction arguments
 * might not be supported.
 */
int
pcap_setdirection(pcap_t *p, pcap_direction_t d)
{
  if (p->setdirection_op == NULL) {
    snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
        "Setting direction is not supported on this device");
    return (-1);
  } else {
    switch (d) {

    case PCAP_D_IN:
    case PCAP_D_OUT:
    case PCAP_D_INOUT:
      /*
       * Valid direction.
       */
      return (p->setdirection_op(p, d));

    default:
      /*
       * Invalid direction.
       */
      snprintf(p->errbuf, sizeof(p->errbuf),
          "Invalid direction");
      return (-1);
    }
  }
}

int
pcap_stats(pcap_t *p, struct pcap_stat *ps)
{
  return (p->stats_op(p, ps));
}

#ifdef _WIN32
struct pcap_stat *
pcap_stats_ex(pcap_t *p, int *pcap_stat_size)
{
  return (p->stats_ex_op(p, pcap_stat_size));
}

int
pcap_setbuff(pcap_t *p, int dim)
{
  return (p->setbuff_op(p, dim));
}

int
pcap_setmode(pcap_t *p, int mode)
{
  return (p->setmode_op(p, mode));
}

int
pcap_setmintocopy(pcap_t *p, int size)
{
  return (p->setmintocopy_op(p, size));
}

HANDLE
pcap_getevent(pcap_t *p)
{
  return (p->getevent_op(p));
}

int
pcap_oid_get_request(pcap_t *p, bpf_u_int32 oid, void *data, size_t *lenp)
{
  return (p->oid_get_request_op(p, oid, data, lenp));
}

int
pcap_oid_set_request(pcap_t *p, bpf_u_int32 oid, const void *data, size_t *lenp)
{
  return (p->oid_set_request_op(p, oid, data, lenp));
}

pcap_send_queue *
pcap_sendqueue_alloc(u_int memsize)
{
  pcap_send_queue *tqueue;

  /* Allocate the queue */
  tqueue = (pcap_send_queue *)malloc(sizeof(pcap_send_queue));
  if (tqueue == NULL){
    return (NULL);
  }

  /* Allocate the buffer */
  tqueue->buffer = (char *)malloc(memsize);
  if (tqueue->buffer == NULL) {
    free(tqueue);
    return (NULL);
  }

  tqueue->maxlen = memsize;
  tqueue->len = 0;

  return (tqueue);
}

void
pcap_sendqueue_destroy(pcap_send_queue *queue)
{
  free(queue->buffer);
  free(queue);
}

int
pcap_sendqueue_queue(pcap_send_queue *queue, const struct pcap_pkthdr *pkt_header, const u_char *pkt_data)
{
  if (queue->len + sizeof(struct pcap_pkthdr) + pkt_header->caplen > queue->maxlen){
    return (-1);
  }

  /* Copy the pcap_pkthdr header*/
  memcpy(queue->buffer + queue->len, pkt_header, sizeof(struct pcap_pkthdr));
  queue->len += sizeof(struct pcap_pkthdr);

  /* copy the packet */
  memcpy(queue->buffer + queue->len, pkt_data, pkt_header->caplen);
  queue->len += pkt_header->caplen;

  return (0);
}

u_int
pcap_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue, int sync)
{
  return (p->sendqueue_transmit_op(p, queue, sync));
}

int
pcap_setuserbuffer(pcap_t *p, int size)
{
  return (p->setuserbuffer_op(p, size));
}

int
pcap_live_dump(pcap_t *p, char *filename, int maxsize, int maxpacks)
{
  return (p->live_dump_op(p, filename, maxsize, maxpacks));
}

int
pcap_live_dump_ended(pcap_t *p, int sync)
{
  return (p->live_dump_ended_op(p, sync));
}

PAirpcapHandle
pcap_get_airpcap_handle(pcap_t *p)
{
  PAirpcapHandle handle;

  handle = p->get_airpcap_handle_op(p);
  if (handle == NULL) {
    (void)snprintf(p->errbuf, sizeof(p->errbuf),
        "This isn't an AirPcap device");
  }
  return (handle);
}
#endif

/*
 * On some platforms, we need to clean up promiscuous or monitor mode
 * when we close a device - and we want that to happen even if the
 * application just exits without explicitl closing devices.
 * On those platforms, we need to register a "close all the pcaps"
 * routine to be called when we exit, and need to maintain a list of
 * pcaps that need to be closed to clean up modes.
 *
 * XXX - not thread-safe.
 */

/*
 * List of pcaps on which we've done something that needs to be
 * cleaned up.
 * If there are any such pcaps, we arrange to call "pcap_close_all()"
 * when we exit, and have it close all of them.
 */
static struct pcap *pcaps_to_close;

/*
 * TRUE if we've already called "atexit()" to cause "pcap_close_all()" to
 * be called on exit.
 */
static int did_atexit;

static void
pcap_close_all(void)
{
  struct pcap *handle;

  while ((handle = pcaps_to_close) != NULL) {
    pcap_close(handle);

    /*
     * If a pcap module adds a pcap_t to the "close all"
     * list by calling pcap_add_to_pcaps_to_close(), it
     * must have a cleanup routine that removes it from the
     * list, by calling pcap_remove_from_pcaps_to_close(),
     * and must make that cleanup routine the cleanup_op
     * for the pcap_t.
     *
     * That means that, after pcap_close() - which calls
     * the cleanup_op for the pcap_t - the pcap_t must
     * have been removed from the list, so pcaps_to_close
     * must not be equal to handle.
     *
     * We check for that, and abort if handle is still
     * at the head of the list, to prevent infinite loops.
     */
    if (pcaps_to_close == handle)
      abort();
  }
}

int
pcap_do_addexit(pcap_t *p)
{
  /*
   * If we haven't already done so, arrange to have
   * "pcap_close_all()" called when we exit.
   */
  if (!did_atexit) {
    if (atexit(pcap_close_all) != 0) {
      /*
       * "atexit()" failed; let our caller know.
       */
      pcap_strlcpy(p->errbuf, "atexit failed", PCAP_ERRBUF_SIZE);
      return (0);
    }
    did_atexit = 1;
  }
  return (1);
}

void
pcap_add_to_pcaps_to_close(pcap_t *p)
{
  p->next = pcaps_to_close;
  pcaps_to_close = p;
}

void
pcap_remove_from_pcaps_to_close(pcap_t *p)
{
  pcap_t *pc, *prevpc;

  for (pc = pcaps_to_close, prevpc = NULL; pc != NULL;
      prevpc = pc, pc = pc->next) {
    if (pc == p) {
      /*
       * Found it.  Remove it from the list.
       */
      if (prevpc == NULL) {
        /*
         * It was at the head of the list.
         */
        pcaps_to_close = pc->next;
      } else {
        /*
         * It was in the middle of the list.
         */
        prevpc->next = pc->next;
      }
      break;
    }
  }
}

void
pcap_breakloop_common(pcap_t *p)
{
  p->break_loop = 1;
}


void
pcap_cleanup_live_common(pcap_t *p)
{
  if (p->opt.device != NULL) {
    free(p->opt.device);
    p->opt.device = NULL;
  }
  if (p->buffer != NULL) {
    free(p->buffer);
    p->buffer = NULL;
  }
  if (p->dlt_list != NULL) {
    free(p->dlt_list);
    p->dlt_list = NULL;
    p->dlt_count = 0;
  }
  if (p->tstamp_type_list != NULL) {
    free(p->tstamp_type_list);
    p->tstamp_type_list = NULL;
    p->tstamp_type_count = 0;
  }
  if (p->tstamp_precision_list != NULL) {
    free(p->tstamp_precision_list);
    p->tstamp_precision_list = NULL;
    p->tstamp_precision_count = 0;
  }
  pcap_freecode(&p->fcode);
#if !defined(_WIN32) && !defined(MSDOS)
  if (p->fd >= 0) {
    close(p->fd);
    p->fd = -1;
  }
  p->selectable_fd = -1;
#endif
}

/*
 * API compatible with WinPcap's "send a packet" routine - returns -1
 * on error, 0 otherwise.
 *
 * XXX - what if we get a short write?
 */
int
pcap_sendpacket(pcap_t *p, const u_char *buf, int size)
{
  if (size <= 0) {
    pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
        errno, "The number of bytes to be sent must be positive");
    return (PCAP_ERROR);
  }

  if (p->inject_op(p, buf, size) == -1)
    return (-1);
  return (0);
}

/*
 * API compatible with OpenBSD's "send a packet" routine - returns -1 on
 * error, number of bytes written otherwise.
 */
int
pcap_inject(pcap_t *p, const void *buf, size_t size)
{
  /*
   * We return the number of bytes written, so the number of
   * bytes to write must fit in an int.
   */
  if (size > INT_MAX) {
    pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
        errno, "More than %d bytes cannot be injected", INT_MAX);
    return (PCAP_ERROR);
  }

  if (size == 0) {
    pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
        errno, "The number of bytes to be injected must not be zero");
    return (PCAP_ERROR);
  }

  return (p->inject_op(p, buf, (int)size));
}

void
pcap_close(pcap_t *p)
{
  p->cleanup_op(p);
  free(p);
}

/*
 * Helpers for safely loading code at run time.
 * Currently Windows-only.
 */
#ifdef _WIN32
//
// This wrapper around loadlibrary appends the system folder (usually
// C:\Windows\System32) to the relative path of the DLL, so that the DLL
// is always loaded from an absolute path (it's no longer possible to
// load modules from the application folder).
// This solves the DLL Hijacking issue discovered in August 2010:
//
// https://blog.rapid7.com/2010/08/23/exploiting-dll-hijacking-flaws/
// https://blog.rapid7.com/2010/08/23/application-dll-load-hijacking/
// (the purported Rapid7 blog post link in the first of those two links
// is broken; the second of those links works.)
//
// If any links there are broken from all the content shuffling Rapid&
// did, see archived versions of the posts at their original homes, at
//
// https://web.archive.org/web/20110122175058/http://blog.metasploit.com/2010/08/exploiting-dll-hijacking-flaws.html
// https://web.archive.org/web/20100828112111/http://blog.rapid7.com/?p=5325
//
pcap_code_handle_t
pcap_load_code(const char *name)
{
  /*
   * XXX - should this work in UTF-16LE rather than in the local
   * ANSI code page?
   */
  CHAR path[MAX_PATH];
  CHAR fullFileName[MAX_PATH];
  UINT res;
  HMODULE hModule = NULL;

  do
  {
    res = GetSystemDirectoryA(path, MAX_PATH);

    if (res == 0) {
      //
      // some bad failure occurred;
      //
      break;
    }

    if (res > MAX_PATH) {
      //
      // the buffer was not big enough
      //
      SetLastError(ERROR_INSUFFICIENT_BUFFER);
      break;
    }

    if (res + 1 + strlen(name) + 1 < MAX_PATH) {
      memcpy(fullFileName, path, res * sizeof(TCHAR));
      fullFileName[res] = '\\';
      memcpy(&fullFileName[res + 1], name, (strlen(name) + 1) * sizeof(TCHAR));

      hModule = LoadLibraryA(fullFileName);
    } else
      SetLastError(ERROR_INSUFFICIENT_BUFFER);

  } while(FALSE);

  return hModule;
}

pcap_funcptr_t
pcap_find_function(pcap_code_handle_t code, const char *func)
{
  return (GetProcAddress(code, func));
}
#endif

/*
 * Given a BPF program, a pcap_pkthdr structure for a packet, and the raw
 * data for the packet, check whether the packet passes the filter.
 * Returns the return value of the filter program, which will be zero if
 * the packet doesn't pass and non-zero if the packet does pass.
 */
int
pcap_offline_filter(const struct bpf_program *fp, const struct pcap_pkthdr *h,
    const u_char *pkt)
{
  const struct bpf_insn *fcode = fp->bf_insns;

  if (fcode != NULL)
    return (pcap_filter(fcode, pkt, h->len, h->caplen));
  else
    return (0);
}

static int
pcap_can_set_rfmon_dead(pcap_t *p)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Rfmon mode doesn't apply on a pcap_open_dead pcap_t");
  return (PCAP_ERROR);
}

static int
pcap_read_dead(pcap_t *p, int cnt _U_, pcap_handler callback _U_,
    u_char *user _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Packets aren't available from a pcap_open_dead pcap_t");
  return (-1);
}

static void
pcap_breakloop_dead(pcap_t *p _U_)
{
  /*
   * A "dead" pcap_t is just a placeholder to use in order to
   * compile a filter to BPF code or to open a savefile for
   * writing.  It doesn't support any operations, including
   * capturing or reading packets, so there will never be a
   * get-packets loop in progress to break out *of*.
   *
   * As such, this routine doesn't need to do anything.
   */
}

static int
pcap_inject_dead(pcap_t *p, const void *buf _U_, int size _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Packets can't be sent on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_setfilter_dead(pcap_t *p, struct bpf_program *fp _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "A filter cannot be set on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_setdirection_dead(pcap_t *p, pcap_direction_t d _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "The packet direction cannot be set on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_set_datalink_dead(pcap_t *p, int dlt _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "The link-layer header type cannot be set on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_getnonblock_dead(pcap_t *p)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "A pcap_open_dead pcap_t does not have a non-blocking mode setting");
  return (-1);
}

static int
pcap_setnonblock_dead(pcap_t *p, int nonblock _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "A pcap_open_dead pcap_t does not have a non-blocking mode setting");
  return (-1);
}

static int
pcap_stats_dead(pcap_t *p, struct pcap_stat *ps _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Statistics aren't available from a pcap_open_dead pcap_t");
  return (-1);
}

#ifdef _WIN32
static struct pcap_stat *
pcap_stats_ex_dead(pcap_t *p, int *pcap_stat_size _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Statistics aren't available from a pcap_open_dead pcap_t");
  return (NULL);
}

static int
pcap_setbuff_dead(pcap_t *p, int dim _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "The kernel buffer size cannot be set on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_setmode_dead(pcap_t *p, int mode _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "impossible to set mode on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_setmintocopy_dead(pcap_t *p, int size _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "The mintocopy parameter cannot be set on a pcap_open_dead pcap_t");
  return (-1);
}

static HANDLE
pcap_getevent_dead(pcap_t *p)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "A pcap_open_dead pcap_t has no event handle");
  return (INVALID_HANDLE_VALUE);
}

static int
pcap_oid_get_request_dead(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_,
    size_t *lenp _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "An OID get request cannot be performed on a pcap_open_dead pcap_t");
  return (PCAP_ERROR);
}

static int
pcap_oid_set_request_dead(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_,
    size_t *lenp _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "An OID set request cannot be performed on a pcap_open_dead pcap_t");
  return (PCAP_ERROR);
}

static u_int
pcap_sendqueue_transmit_dead(pcap_t *p, pcap_send_queue *queue _U_,
    int sync _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Packets cannot be transmitted on a pcap_open_dead pcap_t");
  return (0);
}

static int
pcap_setuserbuffer_dead(pcap_t *p, int size _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "The user buffer cannot be set on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_live_dump_dead(pcap_t *p, char *filename _U_, int maxsize _U_,
    int maxpacks _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");
  return (-1);
}

static int
pcap_live_dump_ended_dead(pcap_t *p, int sync _U_)
{
  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
      "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");
  return (-1);
}

static PAirpcapHandle
pcap_get_airpcap_handle_dead(pcap_t *p _U_)
{
  return (NULL);
}
#endif /* _WIN32 */

static void
pcap_cleanup_dead(pcap_t *p _U_)
{
  /* Nothing to do. */
}

pcap_t *
pcap_open_dead_with_tstamp_precision(int linktype, int snaplen, u_int precision)
{
  pcap_t *p;

  switch (precision) {

  case PCAP_TSTAMP_PRECISION_MICRO:
  case PCAP_TSTAMP_PRECISION_NANO:
    break;

  default:
    /*
     * This doesn't really matter, but we don't have any way
     * to report particular errors, so the only failure we
     * should have is a memory allocation failure.  Just
     * pick microsecond precision.
     */
    precision = PCAP_TSTAMP_PRECISION_MICRO;
    break;
  }
  p = malloc(sizeof(*p));
  if (p == NULL)
    return NULL;
  memset (p, 0, sizeof(*p));
  p->snapshot = snaplen;
  p->linktype = linktype;
  p->opt.tstamp_precision = precision;
  p->can_set_rfmon_op = pcap_can_set_rfmon_dead;
  p->read_op = pcap_read_dead;
  p->inject_op = pcap_inject_dead;
  p->setfilter_op = pcap_setfilter_dead;
  p->setdirection_op = pcap_setdirection_dead;
  p->set_datalink_op = pcap_set_datalink_dead;
  p->getnonblock_op = pcap_getnonblock_dead;
  p->setnonblock_op = pcap_setnonblock_dead;
  p->stats_op = pcap_stats_dead;
#ifdef _WIN32
  p->stats_ex_op = pcap_stats_ex_dead;
  p->setbuff_op = pcap_setbuff_dead;
  p->setmode_op = pcap_setmode_dead;
  p->setmintocopy_op = pcap_setmintocopy_dead;
  p->getevent_op = pcap_getevent_dead;
  p->oid_get_request_op = pcap_oid_get_request_dead;
  p->oid_set_request_op = pcap_oid_set_request_dead;
  p->sendqueue_transmit_op = pcap_sendqueue_transmit_dead;
  p->setuserbuffer_op = pcap_setuserbuffer_dead;
  p->live_dump_op = pcap_live_dump_dead;
  p->live_dump_ended_op = pcap_live_dump_ended_dead;
  p->get_airpcap_handle_op = pcap_get_airpcap_handle_dead;
#endif
  p->breakloop_op = pcap_breakloop_dead;
  p->cleanup_op = pcap_cleanup_dead;

  /*
   * A "dead" pcap_t never requires special BPF code generation.
   */
  p->bpf_codegen_flags = 0;

  p->activated = 1;
  return (p);
}

pcap_t *
pcap_open_dead(int linktype, int snaplen)
{
  return (pcap_open_dead_with_tstamp_precision(linktype, snaplen,
      PCAP_TSTAMP_PRECISION_MICRO));
}

#ifdef YYDEBUG
/*
 * Set the internal "debug printout" flag for the filter expression parser.
 * The code to print that stuff is present only if YYDEBUG is defined, so
 * the flag, and the routine to set it, are defined only if YYDEBUG is
 * defined.
 *
 * This is intended for libpcap developers, not for general use.
 * If you want to set these in a program, you'll have to declare this
 * routine yourself, with the appropriate DLL import attribute on Windows;
 * it's not declared in any header file, and won't be declared in any
 * header file provided by libpcap.
 */
PCAP_API void pcap_set_parser_debug(int value);

PCAP_API_DEF void
pcap_set_parser_debug(int value)
{
  pcap_debug = value;
}
#endif

Coverage Report

Created: 2023-01-25 06:41