/*      $NetBSD: pcap.c,v 1.12 2024/09/02 15:33:37 christos Exp $       */

/*
* 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.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: pcap.c,v 1.12 2024/09/02 15:33:37 christos Exp $");

#include <config.h>

/* Get the same variety of strerror_r() as Autoconf/CMake has detected. */
#include "ftmacros.h"

#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"

#include "thread-local.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_RPCAP
#include "pcap-rpcap-unix.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.)
*/

/*
* Shut down Winsock.
*
* Ignores the return value of WSACleanup(); given that this is
* an atexit() routine, there's nothing much we can do about
* a failure.
*/
static void
internal_wsockfini(void)
{
       WSACleanup();
}

/*
* 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) {
                       pcapint_fmt_errmsg_for_win32_err(errbuf, PCAP_ERRBUF_SIZE,
                           status, "WSAStartup() failed");
               }
               return (err);
       }
       atexit(internal_wsockfini);
       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 pcapint_new_api;            /* pcap_lookupdev() always fails */
int pcapint_utf_8_mode;         /* Strings should be in UTF-8. */

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 (pcapint_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 (!pcapint_utf_8_mode) {
                               snprintf(errbuf, PCAP_ERRBUF_SIZE,
                                   "Multiple pcap_init calls with different character encodings");
                               return (PCAP_ERROR);
                       }
               }
               pcapint_utf_8_mode = 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.
        */
       pcapint_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;
       pcapint_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_, size_t 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) {
                       pcapint_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(p->tstamp_type_count,
                                             sizeof(**tstamp_typesp));
               if (*tstamp_typesp == NULL) {
                       pcapint_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
pcapint_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 = pcapint_offline_read(p, 1, p->oneshot_callback,
                   (u_char *)&s);

               /*
                * Return codes for pcapint_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
        * pcapint_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 (pcapint_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 malloced 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);
       pcapint_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 (pcapint_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 *
pcapint_find_or_add_if(pcap_if_list_t *devlistp, const char *name,
   uint64_t 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 (pcapint_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
pcapint_add_addr_to_if(pcap_if_list_t *devlistp, const char *name,
   uint64_t 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 = pcapint_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 (pcapint_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
pcapint_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) {
               pcapint_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) {
                       pcapint_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) {
                       pcapint_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) {
                       pcapint_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) {
                       pcapint_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 *
pcapint_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 = pcapint_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 (pcapint_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 *
pcapint_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 *
pcapint_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) {
               pcapint_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) {
               pcapint_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) {
                       pcapint_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);
}

/*
* Add an entry for the "any" device.
*/
pcap_if_t *
pcap_add_any_dev(pcap_if_list_t *devlistp, char *errbuf)
{
       static const char any_descr[] = "Pseudo-device that captures on all interfaces";

       /*
        * As it refers to all network devices, not to any particular
        * network device, the notion of "connected" vs. "disconnected"
        * doesn't apply to the "any" device.
        */
       return pcapint_add_dev(devlistp, "any",
           PCAP_IF_UP|PCAP_IF_RUNNING|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
           any_descr, errbuf);
}

/*
* 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 (pcapint_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)pcapint_strlcpy(errbuf, "no suitable device found",
                   PCAP_ERRBUF_SIZE);
               ret = NULL;
       } else {
               /*
                * Return the name of the first device on the list.
                */
               (void)pcapint_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) {
               pcapint_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)pcapint_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
#if defined(__HAIKU__) && defined(__clang__)
       /*
        * In Haiku R1/beta4 <unistd.h> ioctl() is a macro that needs to take 4
        * arguments to initialize its intermediate 2-member structure fully so
        * that Clang does not generate a -Wmissing-field-initializers warning
        * (which manifests only when it runs with -Werror).  This workaround
        * can be removed as soon as there is a Haiku release that fixes the
        * problem.  See also https://review.haiku-os.org/c/haiku/+/6369
        */
       if (ioctl(fd, SIOCGIFADDR, (char *)&ifr, sizeof(ifr)) < 0) {
#else
       if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
#endif /* __HAIKU__ && __clang__ */
               if (errno == EADDRNOTAVAIL) {
                       (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                           "%s: no IPv4 address assigned", device);
               } else {
                       pcapint_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)pcapint_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
#if defined(__HAIKU__) && defined(__clang__)
       /* Same as above. */
       if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr, sizeof(ifr)) < 0) {
#else
       if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
#endif /* __HAIKU__ && __clang__ */
               pcapint_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) {
               pcapint_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) {
                       pcapint_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) {
                       pcapint_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) {
               pcapint_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 (pcapint_strcasecmp(scheme, "file") == 0) {
               *pathp = strdup(colonp + 3);
               if (*pathp == NULL) {
                       pcapint_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 ((pcapint_strcasecmp(scheme, "rpcap") == 0 ||
           pcapint_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) {
                       pcapint_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 everything 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 bracket.
                                */
                               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) {
               pcapint_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
pcapint_createsrcstr_ex(char *source, int type, const char *host, const char *port,
   const char *name, unsigned char uses_ssl, char *errbuf)
{
       switch (type) {

       case PCAP_SRC_FILE:
               pcapint_strlcpy(source, PCAP_SRC_FILE_STRING, PCAP_BUF_SIZE);
               if (name != NULL && *name != '\0') {
                       pcapint_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:
               pcapint_strlcpy(source,
                   (uses_ssl ? "rpcaps://" : PCAP_SRC_IF_STRING),
                   PCAP_BUF_SIZE);
               if (host != NULL && *host != '\0') {
                       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.
                                */
                               pcapint_strlcat(source, "[", PCAP_BUF_SIZE);
                               pcapint_strlcat(source, host, PCAP_BUF_SIZE);
                               pcapint_strlcat(source, "]", PCAP_BUF_SIZE);
                       } else
                               pcapint_strlcat(source, host, PCAP_BUF_SIZE);

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

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

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

               return (0);

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

               if (name != NULL && *name != '\0')
                       pcapint_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 (pcapint_createsrcstr_ex(source, type, host, port, name, 0, errbuf));
}

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

       /* Initialization stuff */
       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)
                       pcapint_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 (host && tmphost) {
                       if (tmpuserinfo)
                               snprintf(host, PCAP_BUF_SIZE, "%s@%s",
                                   tmpuserinfo, tmphost);
                       else
                               pcapint_strlcpy(host, tmphost, PCAP_BUF_SIZE);
               }
               if (port && tmpport)
                       pcapint_strlcpy(port, tmpport, PCAP_BUF_SIZE);
               if (name && tmppath)
                       pcapint_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)
                       pcapint_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)
               pcapint_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 (pcapint_parsesrcstr_ex(source, type, 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 (!pcapint_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) {
                               pcapint_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) {
               pcapint_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 = pcapint_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 pcapint_cleanup_live_common() after
        * doing their own additional cleanup.
        */
       p->cleanup_op = pcapint_cleanup_live_common;

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

       /*
        * Default breakloop operation - implementations can override
        * this, but should call pcapint_breakloop_common() before doing
        * their own logic.
        */
       p->breakloop_op = pcapint_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) {
               pcapint_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 *
pcapint_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
pcapint_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 (pcapint_check_activated(p))
               return (PCAP_ERROR_ACTIVATED);
       p->snapshot = snaplen;
       return (0);
}

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

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

int
pcap_set_timeout(pcap_t *p, int timeout_ms)
{
       if (pcapint_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 (pcapint_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 (pcapint_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 (pcapint_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 (pcapint_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 (pcapint_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 */

               pcapint_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 */

                       pcapint_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 *
pcapint_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 = pcapint_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) {
                       pcapint_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(p->dlt_count, sizeof(**dlt_buffer));
               if (*dlt_buffer == NULL) {
                       pcapint_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
pcapint_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_SENTINEL
};

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

       for (i = 0; dlt_choices[i].name != NULL; i++) {
               if (pcapint_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 thread_local 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 (pcapint_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 programmers
                * 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.
                */
               pcapint_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
pcapint_getnonblock_fd(pcap_t *p)
{
       int fdflags;

       fdflags = fcntl(p->fd, F_GETFL, 0);
       if (fdflags == -1) {
               pcapint_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.
                */
               pcapint_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
pcapint_setnonblock_fd(pcap_t *p, int nonblock)
{
       int fdflags;

       fdflags = fcntl(p->fd, F_GETFL, 0);
       if (fdflags == -1) {
               pcapint_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) {
               pcapint_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 thread_local 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");

       case PCAP_ERROR_CAPTURE_NOTSUP:
               return ("Packet capture is not supported on that device");
       }
       (void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum);
       return(ebuf);
}

/*
* A long time ago the purpose of this function was to hide the difference
* between those Unix-like OSes that implemented strerror() and those that
* didn't.  All the currently supported OSes implement strerror(), which is in
* POSIX.1-2001, uniformly and that particular problem no longer exists.  But
* now they implement a few incompatible thread-safe variants of strerror(),
* and hiding that difference is the current purpose of this function.
*/
const char *
pcap_strerror(int errnum)
{
#ifdef _WIN32
       static thread_local char errbuf[PCAP_ERRBUF_SIZE];
       errno_t err = strerror_s(errbuf, PCAP_ERRBUF_SIZE, errnum);

       if (err != 0) /* err = 0 if successful */
               pcapint_strlcpy(errbuf, "strerror_s() error", PCAP_ERRBUF_SIZE);
       return (errbuf);
#elif defined(HAVE_GNU_STRERROR_R)
       /*
        * We have a GNU-style strerror_r(), which is *not* guaranteed to
        * do anything to the buffer handed to it, and which returns a
        * pointer to the error string, which may or may not be in
        * the buffer.
        *
        * It is, however, guaranteed to succeed.
        *
        * At the time of this writing this applies to the following cases,
        * each of which allows to use either the GNU implementation or the
        * POSIX implementation, and this source tree defines _GNU_SOURCE to
        * use the GNU implementation:
        * - Hurd
        * - Linux with GNU libc
        * - Linux with uClibc-ng
        */
       static thread_local char errbuf[PCAP_ERRBUF_SIZE];
       return strerror_r(errnum, errbuf, PCAP_ERRBUF_SIZE);
#elif defined(HAVE_POSIX_STRERROR_R)
       /*
        * We have a POSIX-style strerror_r(), which is guaranteed to fill
        * in the buffer, but is not guaranteed to succeed.
        *
        * At the time of this writing this applies to the following cases:
        * - AIX 7
        * - FreeBSD
        * - Haiku
        * - HP-UX 11
        * - illumos
        * - Linux with musl libc
        * - macOS
        * - NetBSD
        * - OpenBSD
        * - Solaris 10 & 11
        */
       static thread_local char errbuf[PCAP_ERRBUF_SIZE];
       int err = strerror_r(errnum, errbuf, PCAP_ERRBUF_SIZE);
       switch (err) {
       case 0:
               /* That worked. */
               break;

       case EINVAL:
               /*
                * UNIX 03 says this isn't guaranteed to produce a
                * fallback error message.
                */
               snprintf(errbuf, PCAP_ERRBUF_SIZE,
                        "Unknown error: %d", errnum);
               break;
       case ERANGE:
               /*
                * UNIX 03 says this isn't guaranteed to produce a
                * fallback error message.
                */
               snprintf(errbuf, PCAP_ERRBUF_SIZE,
                        "Message for error %d is too long", errnum);
               break;
       default:
               snprintf(errbuf, PCAP_ERRBUF_SIZE,
                        "strerror_r(%d, ...) unexpectedly returned %d",
                        errnum, err);
       }
       return errbuf;
#else
       /*
        * At the time of this writing every supported OS implements strerror()
        * and at least one thread-safe variant thereof, so this is a very
        * unlikely last-resort branch.  Particular implementations of strerror()
        * may be thread-safe, but this is neither required nor guaranteed.
        */
       return (strerror(errnum));
#endif /* _WIN32 */
}

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 explicitly 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 pcapint_add_to_pcaps_to_close(), it
                * must have a cleanup routine that removes it from the
                * list, by calling pcapint_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
pcapint_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.
                        */
                       pcapint_strlcpy(p->errbuf, "atexit failed", PCAP_ERRBUF_SIZE);
                       return (0);
               }
               did_atexit = 1;
       }
       return (1);
}

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

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


void
pcapint_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) {
               pcapint_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) {
               pcapint_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) {
               pcapint_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, 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
pcapint_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
pcapint_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 (pcapint_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_, size_t 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