Call WSAStartup/WSACleanup for each use. Fixes #1333

[libpcap] / pcap-npf.c

/*
 * Copyright (c) 1999 - 2005 NetGroup, Politecnico di Torino (Italy)
 * Copyright (c) 2005 - 2010 CACE Technologies, Davis (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. Neither the name of the Politecnico di Torino, CACE Technologies
 * nor the names of its contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <config.h>

#include <errno.h>
#include <limits.h> /* for INT_MAX */
#define PCAP_DONT_INCLUDE_PCAP_BPF_H
#include <Packet32.h>
#include <pcap-int.h>
#include <pcap/dlt.h>

/*
 * XXX - Packet32.h defines bpf_program, so we can't include
 * <pcap/bpf.h>, which also defines it; that's why we define
 * PCAP_DONT_INCLUDE_PCAP_BPF_H,
 *
 * However, no header in the WinPcap or Npcap SDKs defines the
 * macros for BPF code, so we have to define them ourselves.
 */
#define         BPF_RET         0x06
#define         BPF_K           0x00

/* Old-school MinGW have these headers in a different place.
 */
#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
  #include <ddk/ntddndis.h>
  #include <ddk/ndis.h>
#else
  #include <ntddndis.h>  /* MSVC/TDM-MinGW/MinGW64 */
#endif

#ifdef HAVE_DAG_API
  #include <dagnew.h>
  #include <dagapi.h>
#endif /* HAVE_DAG_API */

#include "diag-control.h"

#include "pcap-airpcap.h"

static int pcap_setfilter_npf(pcap_t *, struct bpf_program *);
static int pcap_setfilter_win32_dag(pcap_t *, struct bpf_program *);
static int pcap_getnonblock_npf(pcap_t *);
static int pcap_setnonblock_npf(pcap_t *, int);

/*dimension of the buffer in the pcap_t structure*/
#define WIN32_DEFAULT_USER_BUFFER_SIZE 256000

/*dimension of the buffer in the kernel driver NPF */
#define WIN32_DEFAULT_KERNEL_BUFFER_SIZE 1000000

/* Equivalent to ntohs(), but a lot faster under Windows */
#define SWAPS(_X) ((_X & 0xff) << 8) | (_X >> 8)

/*
 * Private data for capturing on WinPcap/Npcap devices.
 */
struct pcap_win {
        ADAPTER *adapter;               /* the packet32 ADAPTER for the device */
        int nonblock;
        int rfmon_selfstart;            /* a flag tells whether the monitor mode is set by itself */
        int filtering_in_kernel;        /* using kernel filter */

#ifdef HAVE_DAG_API
        int     dag_fcs_bits;           /* Number of checksum bits from link layer */
#endif

#ifdef ENABLE_REMOTE
        int samp_npkt;                  /* parameter needed for sampling, with '1 out of N' method has been requested */
        struct timeval samp_time;       /* parameter needed for sampling, with '1 every N ms' method has been requested */
#endif
};

/*
 * Define stub versions of the monitor-mode support routines if this
 * isn't Npcap. HAVE_NPCAP_PACKET_API is defined by Npcap but not
 * WinPcap.
 */
#ifndef HAVE_NPCAP_PACKET_API
static int
PacketIsMonitorModeSupported(PCHAR AdapterName _U_)
{
        /*
         * We don't support monitor mode.
         */
        return (0);
}

static int
PacketSetMonitorMode(PCHAR AdapterName _U_, int mode _U_)
{
        /*
         * This should never be called, as PacketIsMonitorModeSupported()
         * will return 0, meaning "we don't support monitor mode, so
         * don't try to turn it on or off".
         */
        return (0);
}

static int
PacketGetMonitorMode(PCHAR AdapterName _U_)
{
        /*
         * This should fail, so that pcap_activate_npf() returns
         * PCAP_ERROR_RFMON_NOTSUP if our caller requested monitor
         * mode.
         */
        return (-1);
}
#endif

/*
 * If a driver returns an NTSTATUS value:
 *
 *    https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-erref/87fba13e-bf06-450e-83b1-9241dc81e781
 *
 * with the "Customer" bit set, it will not be mapped to a Windows error
 * value in userland, so it will be returned by GetLastError().
 *
 * Note that "driver" here includes the Npcap NPF driver, as various
 * versions would take NT status values and set the "Customer" bit
 * before returning the status code.  The commit message for the
 * change that started doing that is
 *
 *    Returned a customer-defined NTSTATUS in OID requests to avoid
 *    NTSTATUS-to-Win32 Error code translation.
 *
 * but I don't know why the goal was to avoid that translation.  For
 * a while, I suspected that the NT status STATUS_NOT_SUPPORTED was
 * getting mapped to ERROR_GEN_FAILURE, but, in the cases where
 * attempts to set promiscuous mode on regular Ethernet devices were
 * failing with ERROR_GEN_FAILURE, it turns out that the drivers for
 * those devices were NetAdapterCx drivers, and Microsoft's NetAdapterCx
 * mechanism wasn't providing the correct "bytes processed" value on
 * attempts to set OIDs, and the Npcap NPF driver was checking for
 * that and returning STATUS_UNSUCCESSFUL, which gets mapped to
 * ERROR_GEN_FAILURE, so perhaps there's no need to avoid that
 * translation.
 *
 * Attempting to set the hardware filter on a Microsoft Surface Pro's
 * Mobile Broadband Adapter returns an error that appears to be
 * NDIS_STATUS_NOT_SUPPORTED ORed with the "Customer" bit, so it's
 * probably indicating that it doesn't support that.  It was probably
 * the NPF driver setting that bit.
 */
#define NT_STATUS_CUSTOMER_DEFINED      0x20000000

/*
 * PacketRequest() makes a DeviceIoControl() call to the NPF driver to
 * perform the OID request, with a BIOCQUERYOID ioctl.  The kernel code
 * should get back one of NDIS_STATUS_INVALID_OID, NDIS_STATUS_NOT_SUPPORTED,
 * or NDIS_STATUS_NOT_RECOGNIZED if the OID request isn't supported by
 * the OS or the driver.
 *
 * Currently, that code may be returned by the Npcap NPF driver with the
 * NT_STATUS_CUSTOMER_DEFINED bit.  That prevents the return status from
 * being mapped to a Windows error code; if the NPF driver were to stop
 * ORing in the NT_STATUS_CUSTOMER_DEFINED bit, it's not obvious how those
 * the NDIS_STATUS_ values that don't correspond to NTSTATUS values would
 * be translated to Windows error values (NDIS_STATUS_NOT_SUPPORTED is
 * the same as STATUS_NOT_SUPPORTED, which is an NTSTATUS value that is
 * mapped to ERROR_NOT_SUPPORTED).
 */
#define NDIS_STATUS_INVALID_OID         0xc0010017
#define NDIS_STATUS_NOT_SUPPORTED       0xc00000bb      /* STATUS_NOT_SUPPORTED */
#define NDIS_STATUS_NOT_RECOGNIZED      0x00010001

static int
oid_get_request(ADAPTER *adapter, bpf_u_int32 oid, void *data, size_t *lenp,
    char *errbuf)
{
        PACKET_OID_DATA *oid_data_arg;

        /*
         * Allocate a PACKET_OID_DATA structure to hand to PacketRequest().
         * It should be big enough to hold "*lenp" bytes of data; it
         * will actually be slightly larger, as PACKET_OID_DATA has a
         * 1-byte data array at the end, standing in for the variable-length
         * data that's actually there.
         */
        oid_data_arg = malloc(sizeof (PACKET_OID_DATA) + *lenp);
        if (oid_data_arg == NULL) {
                snprintf(errbuf, PCAP_ERRBUF_SIZE,
                    "Couldn't allocate argument buffer for PacketRequest");
                return (PCAP_ERROR);
        }

        /*
         * No need to copy the data - we're doing a fetch.
         */
        oid_data_arg->Oid = oid;
        oid_data_arg->Length = (ULONG)(*lenp);  /* XXX - check for ridiculously large value? */
        if (!PacketRequest(adapter, FALSE, oid_data_arg)) {
                pcapint_fmt_errmsg_for_win32_err(errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "Error calling PacketRequest");
                free(oid_data_arg);
                return (-1);
        }

        /*
         * Get the length actually supplied.
         */
        *lenp = oid_data_arg->Length;

        /*
         * Copy back the data we fetched.
         */
        memcpy(data, oid_data_arg->Data, *lenp);
        free(oid_data_arg);
        return (0);
}

static int
pcap_stats_npf(pcap_t *p, struct pcap_stat *ps)
{
        struct pcap_win *pw = p->priv;
        struct bpf_stat bstats;

        /*
         * Try to get statistics.
         *
         * (Please note - "struct pcap_stat" is *not* the same as
         * WinPcap's "struct bpf_stat". It might currently have the
         * same layout, but let's not cheat.
         *
         * Note also that we don't fill in ps_capt, as we might have
         * been called by code compiled against an earlier version of
         * WinPcap that didn't have ps_capt, in which case filling it
         * in would stomp on whatever comes after the structure passed
         * to us.
         */
        if (!PacketGetStats(pw->adapter, &bstats)) {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "PacketGetStats error");
                return (-1);
        }
        ps->ps_recv = bstats.bs_recv;
        ps->ps_drop = bstats.bs_drop;

        /*
         * XXX - PacketGetStats() doesn't fill this in, so we just
         * return 0.
         */
#if 0
        ps->ps_ifdrop = bstats.ps_ifdrop;
#else
        ps->ps_ifdrop = 0;
#endif

        return (0);
}

/*
 * Win32-only routine for getting statistics.
 *
 * This way is definitely safer than passing the pcap_stat * from the userland.
 * In fact, there could happen than the user allocates a variable which is not
 * big enough for the new structure, and the library will write in a zone
 * which is not allocated to this variable.
 *
 * In this way, we're pretty sure we are writing on memory allocated to this
 * variable.
 *
 * XXX - but this is the wrong way to handle statistics.  Instead, we should
 * have an API that returns data in a form like the Options section of a
 * pcapng Interface Statistics Block:
 *
 *    https://xml2rfc.tools.ietf.org/cgi-bin/xml2rfc.cgi?url=https://raw.githubusercontent.com/pcapng/pcapng/master/draft-tuexen-opsawg-pcapng.xml&modeAsFormat=html/ascii&type=ascii#rfc.section.4.6
 *
 * which would let us add new statistics straightforwardly and indicate which
 * statistics we are and are *not* providing, rather than having to provide
 * possibly-bogus values for statistics we can't provide.
 */
static struct pcap_stat *
pcap_stats_ex_npf(pcap_t *p, int *pcap_stat_size)
{
        struct pcap_win *pw = p->priv;
        struct bpf_stat bstats;

        *pcap_stat_size = sizeof (p->stat);

        /*
         * Try to get statistics.
         *
         * (Please note - "struct pcap_stat" is *not* the same as
         * WinPcap's "struct bpf_stat". It might currently have the
         * same layout, but let's not cheat.)
         */
        if (!PacketGetStatsEx(pw->adapter, &bstats)) {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "PacketGetStatsEx error");
                return (NULL);
        }
        p->stat.ps_recv = bstats.bs_recv;
        p->stat.ps_drop = bstats.bs_drop;
        p->stat.ps_ifdrop = bstats.ps_ifdrop;
        /*
         * Just in case this is ever compiled for a target other than
         * Windows, which is somewhere between extremely unlikely and
         * impossible.
         */
#ifdef _WIN32
        p->stat.ps_capt = bstats.bs_capt;
#endif
        return (&p->stat);
}

/* Set the dimension of the kernel-level capture buffer */
static int
pcap_setbuff_npf(pcap_t *p, int dim)
{
        struct pcap_win *pw = p->priv;

        if(PacketSetBuff(pw->adapter,dim)==FALSE)
        {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: not enough memory to allocate the kernel buffer");
                return (-1);
        }
        return (0);
}

/* Set the driver working mode */
static int
pcap_setmode_npf(pcap_t *p, int mode)
{
        struct pcap_win *pw = p->priv;

        if(PacketSetMode(pw->adapter,mode)==FALSE)
        {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: working mode not recognized");
                return (-1);
        }

        return (0);
}

/*set the minimum amount of data that will release a read call*/
static int
pcap_setmintocopy_npf(pcap_t *p, int size)
{
        struct pcap_win *pw = p->priv;

        if(PacketSetMinToCopy(pw->adapter, size)==FALSE)
        {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: unable to set the requested mintocopy size");
                return (-1);
        }
        return (0);
}

static HANDLE
pcap_getevent_npf(pcap_t *p)
{
        struct pcap_win *pw = p->priv;

        return (PacketGetReadEvent(pw->adapter));
}

static int
pcap_oid_get_request_npf(pcap_t *p, bpf_u_int32 oid, void *data, size_t *lenp)
{
        struct pcap_win *pw = p->priv;

        return (oid_get_request(pw->adapter, oid, data, lenp, p->errbuf));
}

static int
pcap_oid_set_request_npf(pcap_t *p, bpf_u_int32 oid, const void *data,
    size_t *lenp)
{
        struct pcap_win *pw = p->priv;
        PACKET_OID_DATA *oid_data_arg;

        /*
         * Allocate a PACKET_OID_DATA structure to hand to PacketRequest().
         * It should be big enough to hold "*lenp" bytes of data; it
         * will actually be slightly larger, as PACKET_OID_DATA has a
         * 1-byte data array at the end, standing in for the variable-length
         * data that's actually there.
         */
        oid_data_arg = malloc(sizeof (PACKET_OID_DATA) + *lenp);
        if (oid_data_arg == NULL) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Couldn't allocate argument buffer for PacketRequest");
                return (PCAP_ERROR);
        }

        oid_data_arg->Oid = oid;
        oid_data_arg->Length = (ULONG)(*lenp);  /* XXX - check for ridiculously large value? */
        memcpy(oid_data_arg->Data, data, *lenp);
        if (!PacketRequest(pw->adapter, TRUE, oid_data_arg)) {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "Error calling PacketRequest");
                free(oid_data_arg);
                return (PCAP_ERROR);
        }

        /*
         * Get the length actually copied.
         */
        *lenp = oid_data_arg->Length;

        /*
         * No need to copy the data - we're doing a set.
         */
        free(oid_data_arg);
        return (0);
}

static u_int
pcap_sendqueue_transmit_npf(pcap_t *p, pcap_send_queue *queue, int sync)
{
        struct pcap_win *pw = p->priv;
        u_int res;

        res = PacketSendPackets(pw->adapter,
                queue->buffer,
                queue->len,
                (BOOLEAN)sync);

        if(res != queue->len){
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "Error queueing packets");
        }

        return (res);
}

static int
pcap_setuserbuffer_npf(pcap_t *p, int size)
{
        unsigned char *new_buff;

        if (size<=0) {
                /* Bogus parameter */
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Error: invalid size %d",size);
                return (-1);
        }

        /* Allocate the buffer */
        new_buff=(unsigned char*)malloc(sizeof(char)*size);

        if (!new_buff) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Error: not enough memory");
                return (-1);
        }

        free(p->buffer);

        p->buffer=new_buff;
        p->bufsize=size;

        return (0);
}

#ifdef HAVE_NPCAP_PACKET_API
/*
 * Kernel dump mode isn't supported in Npcap; calls to PacketSetDumpName(),
 * PacketSetDumpLimits(), and PacketIsDumpEnded() will get compile-time
 * deprecation warnings.
 *
 * Avoid calling them; just return errors indicating that kernel dump
 * mode isn't supported in Npcap.
 */
static int
pcap_live_dump_npf(pcap_t *p, char *filename _U_, int maxsize _U_,
    int maxpacks _U_)
{
        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
            "Npcap doesn't support kernel dump mode");
        return (-1);
}
static int
pcap_live_dump_ended_npf(pcap_t *p, int sync)
{
        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
            "Npcap doesn't support kernel dump mode");
        return (-1);
}
#else /* HAVE_NPCAP_PACKET_API */
static int
pcap_live_dump_npf(pcap_t *p, char *filename, int maxsize, int maxpacks)
{
        struct pcap_win *pw = p->priv;
        BOOLEAN res;

        /* Set the packet driver in dump mode */
        res = PacketSetMode(pw->adapter, PACKET_MODE_DUMP);
        if(res == FALSE){
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Error setting dump mode");
                return (-1);
        }

        /* Set the name of the dump file */
        res = PacketSetDumpName(pw->adapter, filename, (int)strlen(filename));
        if(res == FALSE){
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Error setting kernel dump file name");
                return (-1);
        }

        /* Set the limits of the dump file */
        res = PacketSetDumpLimits(pw->adapter, maxsize, maxpacks);
        if(res == FALSE) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                                "Error setting dump limit");
                return (-1);
        }

        return (0);
}

static int
pcap_live_dump_ended_npf(pcap_t *p, int sync)
{
        struct pcap_win *pw = p->priv;

        return (PacketIsDumpEnded(pw->adapter, (BOOLEAN)sync));
}
#endif /* HAVE_NPCAP_PACKET_API */

#ifdef HAVE_AIRPCAP_API
static PAirpcapHandle
pcap_get_airpcap_handle_npf(pcap_t *p)
{
        struct pcap_win *pw = p->priv;

        return (PacketGetAirPcapHandle(pw->adapter));
}
#else /* HAVE_AIRPCAP_API */
static PAirpcapHandle
pcap_get_airpcap_handle_npf(pcap_t *p _U_)
{
        return (NULL);
}
#endif /* HAVE_AIRPCAP_API */

static int
pcap_read_npf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
        PACKET Packet;
        u_int cc;
        int n;
        register u_char *bp, *ep;
        u_char *datap;
        struct pcap_win *pw = p->priv;

        cc = p->cc;
        if (cc == 0) {
                /*
                 * Has "pcap_breakloop()" been called?
                 */
                if (p->break_loop) {
                        /*
                         * Yes - clear the flag that indicates that it
                         * has, and return PCAP_ERROR_BREAK to indicate
                         * that we were told to break out of the loop.
                         */
                        p->break_loop = 0;
                        return (PCAP_ERROR_BREAK);
                }

                /*
                 * Capture the packets.
                 *
                 * The PACKET structure had a bunch of extra stuff for
                 * Windows 9x/Me, but the only interesting data in it
                 * in the versions of Windows that we support is just
                 * a copy of p->buffer, a copy of p->buflen, and the
                 * actual number of bytes read returned from
                 * PacketReceivePacket(), none of which has to be
                 * retained from call to call, so we just keep one on
                 * the stack.
                 */
                PacketInitPacket(&Packet, (BYTE *)p->buffer, p->bufsize);
                if (!PacketReceivePacket(pw->adapter, &Packet, TRUE)) {
                        /*
                         * Did the device go away?
                         * If so, the error we get can either be
                         * ERROR_GEN_FAILURE or ERROR_DEVICE_REMOVED.
                         */
                        DWORD errcode = GetLastError();

                        if (errcode == ERROR_GEN_FAILURE ||
                            errcode == ERROR_DEVICE_REMOVED) {
                                /*
                                 * The device on which we're capturing
                                 * went away, or it became unusable
                                 * by NPF due to a suspend/resume.
                                 *
                                 * ERROR_GEN_FAILURE comes from
                                 * STATUS_UNSUCCESSFUL, as well as some
                                 * other NT status codes that the Npcap
                                 * driver is unlikely to return.
                                 * XXX - hopefully no other error
                                 * conditions are indicated by this.
                                 *
                                 * ERROR_DEVICE_REMOVED comes from
                                 * STATUS_DEVICE_REMOVED.
                                 *
                                 * We report the Windows status code
                                 * name and the corresponding NT status
                                 * code name, for the benefit of attempts
                                 * to debug cases where this error is
                                 * reported when the device *wasn't*
                                 * removed, either because it's not
                                 * removable, it's removable but wasn't
                                 * removed, or it's a device that doesn't
                                 * correspond to a physical device.
                                 *
                                 * XXX - we really should return an
                                 * appropriate error for that, but
                                 * pcap_dispatch() etc. aren't
                                 * documented as having error returns
                                 * other than PCAP_ERROR or PCAP_ERROR_BREAK.
                                 */
                                const char *errcode_msg;

                                if (errcode == ERROR_GEN_FAILURE)
                                        errcode_msg = "ERROR_GEN_FAILURE/STATUS_UNSUCCESSFUL";
                                else
                                        errcode_msg = "ERROR_DEVICE_REMOVED/STATUS_DEVICE_REMOVED";
                                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                                    "The interface disappeared (error code %s)",
                                    errcode_msg);
                        } else {
                                pcapint_fmt_errmsg_for_win32_err(p->errbuf,
                                    PCAP_ERRBUF_SIZE, errcode,
                                    "PacketReceivePacket error");
                        }
                        return (PCAP_ERROR);
                }

                cc = Packet.ulBytesReceived;

                bp = p->buffer;
        }
        else
                bp = p->bp;

        /*
         * Loop through each packet.
         *
         * This assumes that a single buffer of packets will have
         * <= INT_MAX packets, so the packet count doesn't overflow.
         */
#define bhp ((struct bpf_hdr *)bp)
        n = 0;
        ep = bp + cc;
        for (;;) {
                register u_int caplen, hdrlen;
                size_t packet_bytes;

                /*
                 * Has "pcap_breakloop()" been called?
                 * If so, return immediately - if we haven't read any
                 * packets, clear the flag and return PCAP_ERROR_BREAK
                 * to indicate that we were told to break out of the loop,
                 * otherwise leave the flag set, so that the *next* call
                 * will break out of the loop without having read any
                 * packets, and return the number of packets we've
                 * processed so far.
                 */
                if (p->break_loop) {
                        if (n == 0) {
                                p->break_loop = 0;
                                return (PCAP_ERROR_BREAK);
                        } else {
                                p->bp = bp;
                                p->cc = (u_int) (ep - bp);
                                return (n);
                        }
                }
                if (bp >= ep)
                        break;

                caplen = bhp->bh_caplen;
                hdrlen = bhp->bh_hdrlen;
                datap = bp + hdrlen;

                /*
                 * Compute the number of bytes for this packet in
                 * the buffer.
                 *
                 * That's the sum of the header length and the packet
                 * data length plus, if this is not the last packet,
                 * the padding required to align the next packet on
                 * the appropriate boundary.
                 *
                 * That means that it should be the minimum of the
                 * number of bytes left in the buffer and the
                 * rounded-up sum of the header and packet data lengths.
                 */
                packet_bytes = min((u_int)(ep - bp), Packet_WORDALIGN(caplen + hdrlen));

                /*
                 * Short-circuit evaluation: if using BPF filter
                 * in kernel, no need to do it now - we already know
                 * the packet passed the filter.
                 *
                 * XXX - pcapint_filter() should always return TRUE if
                 * handed a null pointer for the program, but it might
                 * just try to "run" the filter, so we check here.
                 */
                if (pw->filtering_in_kernel ||
                    p->fcode.bf_insns == NULL ||
                    pcapint_filter(p->fcode.bf_insns, datap, bhp->bh_datalen, caplen)) {
#ifdef ENABLE_REMOTE
                        switch (p->rmt_samp.method) {

                        case PCAP_SAMP_1_EVERY_N:
                                pw->samp_npkt = (pw->samp_npkt + 1) % p->rmt_samp.value;

                                /* Discard all packets that are not '1 out of N' */
                                if (pw->samp_npkt != 0) {
                                        bp += packet_bytes;
                                        continue;
                                }
                                break;

                        case PCAP_SAMP_FIRST_AFTER_N_MS:
                            {
                                struct pcap_pkthdr *pkt_header = (struct pcap_pkthdr*) bp;

                                /*
                                 * Check if the timestamp of the arrived
                                 * packet is smaller than our target time.
                                 */
                                if (pkt_header->ts.tv_sec < pw->samp_time.tv_sec ||
                                   (pkt_header->ts.tv_sec == pw->samp_time.tv_sec && pkt_header->ts.tv_usec < pw->samp_time.tv_usec)) {
                                        bp += packet_bytes;
                                        continue;
                                }

                                /*
                                 * The arrived packet is suitable for being
                                 * delivered to our caller, so let's update
                                 * the target time.
                                 */
                                pw->samp_time.tv_usec = pkt_header->ts.tv_usec + p->rmt_samp.value * 1000;
                                if (pw->samp_time.tv_usec > 1000000) {
                                        pw->samp_time.tv_sec = pkt_header->ts.tv_sec + pw->samp_time.tv_usec / 1000000;
                                        pw->samp_time.tv_usec = pw->samp_time.tv_usec % 1000000;
                                }
                            }
                        }
#endif  /* ENABLE_REMOTE */

                        /*
                         * XXX A bpf_hdr matches a pcap_pkthdr.
                         */
                        (*callback)(user, (struct pcap_pkthdr*)bp, datap);
                        bp += packet_bytes;
                        if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
                                p->bp = bp;
                                p->cc = (u_int) (ep - bp);
                                return (n);
                        }
                } else {
                        /*
                         * Skip this packet.
                         */
                        bp += packet_bytes;
                }
        }
#undef bhp
        p->cc = 0;
        return (n);
}

#ifdef HAVE_DAG_API
static int
pcap_read_win32_dag(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
        struct pcap_win *pw = p->priv;
        PACKET Packet;
        u_char *dp = NULL;
        int     packet_len = 0, caplen = 0;
        struct pcap_pkthdr      pcap_header;
        u_char *endofbuf;
        int n = 0;
        dag_record_t *header;
        unsigned erf_record_len;
        ULONGLONG ts;
        int cc;
        unsigned swt;
        unsigned dfp = pw->adapter->DagFastProcess;

        cc = p->cc;
        if (cc == 0) /* Get new packets only if we have processed all the ones of the previous read */
        {
                /*
                 * Get new packets from the network.
                 *
                 * The PACKET structure had a bunch of extra stuff for
                 * Windows 9x/Me, but the only interesting data in it
                 * in the versions of Windows that we support is just
                 * a copy of p->buffer, a copy of p->buflen, and the
                 * actual number of bytes read returned from
                 * PacketReceivePacket(), none of which has to be
                 * retained from call to call, so we just keep one on
                 * the stack.
                 */
                PacketInitPacket(&Packet, (BYTE *)p->buffer, p->bufsize);
                if (!PacketReceivePacket(pw->adapter, &Packet, TRUE)) {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read error: PacketReceivePacket failed");
                        return (-1);
                }

                cc = Packet.ulBytesReceived;
                if(cc == 0)
                        /* The timeout has expired but we no packets arrived */
                        return (0);
                header = (dag_record_t*)pw->adapter->DagBuffer;
        }
        else
                header = (dag_record_t*)p->bp;

        endofbuf = (char*)header + cc;

        /*
         * This can conceivably process more than INT_MAX packets,
         * which would overflow the packet count, causing it either
         * to look like a negative number, and thus cause us to
         * return a value that looks like an error, or overflow
         * back into positive territory, and thus cause us to
         * return a too-low count.
         *
         * Therefore, if the packet count is unlimited, we clip
         * it at INT_MAX; this routine is not expected to
         * process packets indefinitely, so that's not an issue.
         */
        if (PACKET_COUNT_IS_UNLIMITED(cnt))
                cnt = INT_MAX;

        /*
         * Cycle through the packets
         */
        do
        {
                erf_record_len = SWAPS(header->rlen);
                if((char*)header + erf_record_len > endofbuf)
                        break;

                /* Increase the number of captured packets */
                p->stat.ps_recv++;

                /* Find the beginning of the packet */
                dp = ((u_char *)header) + dag_record_size;

                /* Determine actual packet len */
                switch(header->type)
                {
                case TYPE_ATM:
                        packet_len = ATM_SNAPLEN;
                        caplen = ATM_SNAPLEN;
                        dp += 4;

                        break;

                case TYPE_ETH:
                        swt = SWAPS(header->wlen);
                        packet_len = swt - (pw->dag_fcs_bits);
                        caplen = erf_record_len - dag_record_size - 2;
                        if (caplen > packet_len)
                        {
                                caplen = packet_len;
                        }
                        dp += 2;

                        break;

                case TYPE_HDLC_POS:
                        swt = SWAPS(header->wlen);
                        packet_len = swt - (pw->dag_fcs_bits);
                        caplen = erf_record_len - dag_record_size;
                        if (caplen > packet_len)
                        {
                                caplen = packet_len;
                        }

                        break;
                }

                if(caplen > p->snapshot)
                        caplen = p->snapshot;

                /*
                 * Has "pcap_breakloop()" been called?
                 * If so, return immediately - if we haven't read any
                 * packets, clear the flag and return -2 to indicate
                 * that we were told to break out of the loop, otherwise
                 * leave the flag set, so that the *next* call will break
                 * out of the loop without having read any packets, and
                 * return the number of packets we've processed so far.
                 */
                if (p->break_loop)
                {
                        if (n == 0)
                        {
                                p->break_loop = 0;
                                return (-2);
                        }
                        else
                        {
                                p->bp = (char*)header;
                                p->cc = endofbuf - (char*)header;
                                return (n);
                        }
                }

                if(!dfp)
                {
                        /* convert between timestamp formats */
                        ts = header->ts;
                        pcap_header.ts.tv_sec = (int)(ts >> 32);
                        ts = (ts & 0xffffffffi64) * 1000000;
                        ts += 0x80000000; /* rounding */
                        pcap_header.ts.tv_usec = (int)(ts >> 32);
                        if (pcap_header.ts.tv_usec >= 1000000) {
                                pcap_header.ts.tv_usec -= 1000000;
                                pcap_header.ts.tv_sec++;
                        }
                }

                /* No underlying filtering system. We need to filter on our own */
                if (p->fcode.bf_insns)
                {
                        if (pcapint_filter(p->fcode.bf_insns, dp, packet_len, caplen) == 0)
                        {
                                /* Move to next packet */
                                header = (dag_record_t*)((char*)header + erf_record_len);
                                continue;
                        }
                }

                /* Fill the header for the user supplied callback function */
                pcap_header.caplen = caplen;
                pcap_header.len = packet_len;

                /* Call the callback function */
                (*callback)(user, &pcap_header, dp);

                /* Move to next packet */
                header = (dag_record_t*)((char*)header + erf_record_len);

                /* Stop if the number of packets requested by user has been reached*/
                if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt))
                {
                        p->bp = (char*)header;
                        p->cc = endofbuf - (char*)header;
                        return (n);
                }
        }
        while((u_char*)header < endofbuf);

        return (1);
}
#endif /* HAVE_DAG_API */

/* Send a packet to the network */
static int
pcap_inject_npf(pcap_t *p, const void *buf, int size)
{
        struct pcap_win *pw = p->priv;
        PACKET pkt;

        PacketInitPacket(&pkt, (PVOID)buf, size);
        if(PacketSendPacket(pw->adapter,&pkt,TRUE) == FALSE) {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "send error: PacketSendPacket failed");
                return (-1);
        }

        /*
         * We assume it all got sent if "PacketSendPacket()" succeeded.
         * "pcap_inject()" is expected to return the number of bytes
         * sent.
         */
        return (size);
}

static void
pcap_cleanup_npf(pcap_t *p)
{
        struct pcap_win *pw = p->priv;

        if (pw->adapter != NULL) {
                PacketCloseAdapter(pw->adapter);
                pw->adapter = NULL;
        }
        if (pw->rfmon_selfstart)
        {
                PacketSetMonitorMode(p->opt.device, 0);
        }
        pcapint_cleanup_live_common(p);
}

static void
pcap_breakloop_npf(pcap_t *p)
{
        pcapint_breakloop_common(p);
        struct pcap_win *pw = p->priv;

        /* XXX - what if this fails? */
        SetEvent(PacketGetReadEvent(pw->adapter));
}

static int
pcap_activate_npf(pcap_t *p)
{
        struct pcap_win *pw = p->priv;
        NetType type;
        int res;
        int status = 0;
        struct bpf_insn total_insn;
        struct bpf_program total_prog;

        if (p->opt.rfmon) {
                /*
                 * Monitor mode is supported on Windows Vista and later.
                 */
                if (PacketGetMonitorMode(p->opt.device) == 1)
                {
                        pw->rfmon_selfstart = 0;
                }
                else
                {
                        if ((res = PacketSetMonitorMode(p->opt.device, 1)) != 1)
                        {
                                pw->rfmon_selfstart = 0;
                                // Monitor mode is not supported.
                                if (res == 0)
                                {
                                        return PCAP_ERROR_RFMON_NOTSUP;
                                }
                                else
                                {
                                        return PCAP_ERROR;
                                }
                        }
                        else
                        {
                                pw->rfmon_selfstart = 1;
                        }
                }
        }

        pw->adapter = PacketOpenAdapter(p->opt.device);

        if (pw->adapter == NULL)
        {
                DWORD errcode = GetLastError();

                /*
                 * What error did we get when trying to open the adapter?
                 */
                switch (errcode) {

                case ERROR_BAD_UNIT:
                        /*
                         * There's no such device.
                         * There's nothing to add, so clear the error
                         * message.
                         */
                        p->errbuf[0] = '\0';
                        return (PCAP_ERROR_NO_SUCH_DEVICE);

                case ERROR_ACCESS_DENIED:
                        /*
                         * There is, but we don't have permission to
                         * use it.
                         *
                         * XXX - we currently get ERROR_BAD_UNIT if the
                         * user says "no" to the UAC prompt.
                         */
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "The helper program for \"Admin-only Mode\" must be allowed to make changes to your device");
                        return (PCAP_ERROR_PERM_DENIED);

                default:
                        /*
                         * Unknown - report details.
                         */
                        pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                            errcode, "Error opening adapter");
                        if (pw->rfmon_selfstart)
                        {
                                PacketSetMonitorMode(p->opt.device, 0);
                        }
                        return (PCAP_ERROR);
                }
        }

        /*get network type*/
        if(PacketGetNetType (pw->adapter,&type) == FALSE)
        {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "Cannot determine the network type");
                goto bad;
        }

        /*Set the linktype*/
        switch (type.LinkType)
        {
        /*
         * NDIS-defined medium types.
         */
        case NdisMedium802_3:
                p->linktype = DLT_EN10MB;
                /*
                 * This is (presumably) a real Ethernet capture; give it a
                 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
                 * that an application can let you choose it, in case you're
                 * capturing DOCSIS traffic that a Cisco Cable Modem
                 * Termination System is putting out onto an Ethernet (it
                 * doesn't put an Ethernet header onto the wire, it puts raw
                 * DOCSIS frames out on the wire inside the low-level
                 * Ethernet framing).
                 */
                p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
                if (p->dlt_list == NULL)
                {
                        pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                            errno, "malloc");
                        goto bad;
                }
                p->dlt_list[0] = DLT_EN10MB;
                p->dlt_list[1] = DLT_DOCSIS;
                p->dlt_count = 2;
                break;

        case NdisMedium802_5:
                /*
                 * Token Ring.
                 */
                p->linktype = DLT_IEEE802;
                break;

        case NdisMediumFddi:
                p->linktype = DLT_FDDI;
                break;

        case NdisMediumWan:
                p->linktype = DLT_EN10MB;
                break;

        case NdisMediumArcnetRaw:
                p->linktype = DLT_ARCNET;
                break;

        case NdisMediumArcnet878_2:
                p->linktype = DLT_ARCNET;
                break;

        case NdisMediumAtm:
                p->linktype = DLT_ATM_RFC1483;
                break;

        case NdisMediumWirelessWan:
                p->linktype = DLT_RAW;
                break;

        case NdisMediumIP:
                p->linktype = DLT_RAW;
                break;

        /*
         * Npcap-defined medium types.
         */
        case NdisMediumNull:
                p->linktype = DLT_NULL;
                break;

        case NdisMediumCHDLC:
                p->linktype = DLT_CHDLC;
                break;

        case NdisMediumPPPSerial:
                p->linktype = DLT_PPP_SERIAL;
                break;

        case NdisMediumBare80211:
                p->linktype = DLT_IEEE802_11;
                break;

        case NdisMediumRadio80211:
                p->linktype = DLT_IEEE802_11_RADIO;
                break;

        case NdisMediumPpi:
                p->linktype = DLT_PPI;
                break;

        default:
                /*
                 * An unknown medium type is assumed to supply Ethernet
                 * headers; if not, the user will have to report it,
                 * so that the medium type and link-layer header type
                 * can be determined.  If we were to fail here, we
                 * might get the link-layer type in the error, but
                 * the user wouldn't get a capture, so we wouldn't
                 * be able to determine the link-layer type; we report
                 * a warning with the link-layer type, so at least
                 * some programs will report the warning.
                 */
                p->linktype = DLT_EN10MB;
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "Unknown NdisMedium value %d, defaulting to DLT_EN10MB",
                    type.LinkType);
                status = PCAP_WARNING;
                break;
        }

#ifdef HAVE_PACKET_GET_TIMESTAMP_MODES
        /*
         * Set the timestamp type.
         * (Yes, we require PacketGetTimestampModes(), not just
         * PacketSetTimestampMode().  If we have the former, we
         * have the latter, unless somebody's using a version
         * of Npcap that they've hacked to provide the former
         * but not the latter; if they've done that, either
         * they're confused or they're trolling us.)
         */
        switch (p->opt.tstamp_type) {

        case PCAP_TSTAMP_HOST_HIPREC_UNSYNCED:
                /*
                 * Better than low-res, but *not* synchronized with
                 * the OS clock.
                 */
                if (!PacketSetTimestampMode(pw->adapter, TIMESTAMPMODE_SINGLE_SYNCHRONIZATION))
                {
                        pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                            GetLastError(), "Cannot set the time stamp mode to TIMESTAMPMODE_SINGLE_SYNCHRONIZATION");
                        goto bad;
                }
                break;

        case PCAP_TSTAMP_HOST_LOWPREC:
                /*
                 * Low-res, but synchronized with the OS clock.
                 */
                if (!PacketSetTimestampMode(pw->adapter, TIMESTAMPMODE_QUERYSYSTEMTIME))
                {
                        pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                            GetLastError(), "Cannot set the time stamp mode to TIMESTAMPMODE_QUERYSYSTEMTIME");
                        goto bad;
                }
                break;

        case PCAP_TSTAMP_HOST_HIPREC:
                /*
                 * High-res, and synchronized with the OS clock.
                 */
                if (!PacketSetTimestampMode(pw->adapter, TIMESTAMPMODE_QUERYSYSTEMTIME_PRECISE))
                {
                        pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                            GetLastError(), "Cannot set the time stamp mode to TIMESTAMPMODE_QUERYSYSTEMTIME_PRECISE");
                        goto bad;
                }
                break;

        case PCAP_TSTAMP_HOST:
                /*
                 * XXX - do whatever the default is, for now.
                 * Set to the highest resolution that's synchronized
                 * with the system clock?
                 */
                break;
        }
#endif /* HAVE_PACKET_GET_TIMESTAMP_MODES */

        /*
         * Turn a negative snapshot value (invalid), a snapshot value of
         * 0 (unspecified), or a value bigger than the normal maximum
         * value, into the maximum allowed value.
         *
         * If some application really *needs* a bigger snapshot
         * length, we should just increase MAXIMUM_SNAPLEN.
         */
        if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
                p->snapshot = MAXIMUM_SNAPLEN;

        /* Set promiscuous mode */
        if (p->opt.promisc)
        {
                /*
                 * For future reference, in case we ever want to query
                 * whether an adapter supports promiscuous mode, that
                 * would be done on Windows by querying the value
                 * of the OID_GEN_SUPPORTED_PACKET_FILTERS OID.
                 */
                if (PacketSetHwFilter(pw->adapter,NDIS_PACKET_TYPE_PROMISCUOUS) == FALSE)
                {
                        DWORD errcode = GetLastError();

                        /*
                         * Suppress spurious error generated by non-compliant
                         * MS Surface mobile adapters that appear to
                         * return NDIS_STATUS_NOT_SUPPORTED for attempts
                         * to set the hardware filter.
                         *
                         * It appears to be reporting NDIS_STATUS_NOT_SUPPORTED,
                         * but with the NT status value "Customer" bit set;
                         * the Npcap NPF driver sets that bit in some cases.
                         *
                         * If we knew that this meant "promiscuous mode
                         * isn't supported", we could add a "promiscuous
                         * mode isn't supported" error code and return
                         * that, but:
                         *
                         *    1) we don't know that it means that
                         *    rather than meaning "we reject attempts
                         *    to set the filter, even though the NDIS
                         *    specifications say you shouldn't do that"
                         *
                         * and
                         *
                         *    2) other interface types that don't
                         *    support promiscuous mode, at least
                         *    on UN*Xes, just silently ignore
                         *    attempts to set promiscuous mode
                         *
                         * and rejecting it with an error could disrupt
                         * attempts to capture, as many programs (tcpdump,
                         * *shark) default to promiscuous mode.
                         *
                         * Alternatively, we could return the "promiscuous
                         * mode not supported" *warning* value, so that
                         * correct code will either ignore it or report
                         * it and continue capturing.  (This may require
                         * a pcap_init() flag to request that return
                         * value, so that old incorrect programs that
                         * assume a non-zero return from pcap_activate()
                         * is an error don't break.)
                         *
                         * We check here for ERROR_NOT_SUPPORTED, which
                         * is what NDIS_STATUS_NOT_SUPPORTED (which is
                         * the same value as the NTSTATUS value
                         * STATUS_NOT_SUPPORTED) gets mapped to, as
                         * well as NDIS_STATUS_NOT_SUPPORTED with the
                         * "Customer" bit set.
                         */
                        if (errcode != ERROR_NOT_SUPPORTED &&
                            errcode != (NDIS_STATUS_NOT_SUPPORTED|NT_STATUS_CUSTOMER_DEFINED))
                        {
                                pcapint_fmt_errmsg_for_win32_err(p->errbuf,
                                    PCAP_ERRBUF_SIZE, errcode,
                                    "failed to set hardware filter to promiscuous mode");
                                goto bad;
                        }
                }
        }
        else
        {
                /*
                 * NDIS_PACKET_TYPE_ALL_LOCAL selects "All packets sent by
                 * installed protocols and all packets indicated by the NIC",
                 * but if no protocol drivers (like TCP/IP) are installed,
                 * NDIS_PACKET_TYPE_DIRECTED, NDIS_PACKET_TYPE_BROADCAST,
                 * and NDIS_PACKET_TYPE_MULTICAST are needed to capture
                 * incoming frames.
                 */
                if (PacketSetHwFilter(pw->adapter,
                        NDIS_PACKET_TYPE_ALL_LOCAL |
                        NDIS_PACKET_TYPE_DIRECTED |
                        NDIS_PACKET_TYPE_BROADCAST |
                        NDIS_PACKET_TYPE_MULTICAST) == FALSE)
                {
                        DWORD errcode = GetLastError();

                        /*
                         * Suppress spurious error generated by non-compliant
                         * MS Surface mobile adapters.
                         */
                        if (errcode != (NDIS_STATUS_NOT_SUPPORTED|NT_STATUS_CUSTOMER_DEFINED))
                        {
                                pcapint_fmt_errmsg_for_win32_err(p->errbuf,
                                    PCAP_ERRBUF_SIZE, errcode,
                                    "failed to set hardware filter to non-promiscuous mode");
                                goto bad;
                        }
                }
        }

        /* Set the buffer size */
        p->bufsize = WIN32_DEFAULT_USER_BUFFER_SIZE;

        if(!(pw->adapter->Flags & INFO_FLAG_DAG_CARD))
        {
        /*
         * Traditional Adapter
         */
                /*
                 * If the buffer size wasn't explicitly set, default to
                 * WIN32_DEFAULT_KERNEL_BUFFER_SIZE.
                 */
                if (p->opt.buffer_size == 0)
                        p->opt.buffer_size = WIN32_DEFAULT_KERNEL_BUFFER_SIZE;

                if(PacketSetBuff(pw->adapter,p->opt.buffer_size)==FALSE)
                {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: not enough memory to allocate the kernel buffer");
                        goto bad;
                }

                p->buffer = malloc(p->bufsize);
                if (p->buffer == NULL)
                {
                        pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                            errno, "malloc");
                        goto bad;
                }

                if (p->opt.immediate)
                {
                        /* tell the driver to copy the buffer as soon as data arrives */
                        if(PacketSetMinToCopy(pw->adapter,0)==FALSE)
                        {
                                pcapint_fmt_errmsg_for_win32_err(p->errbuf,
                                    PCAP_ERRBUF_SIZE, GetLastError(),
                                    "Error calling PacketSetMinToCopy");
                                goto bad;
                        }
                }
                else
                {
                        /* tell the driver to copy the buffer only if it contains at least 16K */
                        if(PacketSetMinToCopy(pw->adapter,16000)==FALSE)
                        {
                                pcapint_fmt_errmsg_for_win32_err(p->errbuf,
                                    PCAP_ERRBUF_SIZE, GetLastError(),
                                    "Error calling PacketSetMinToCopy");
                                goto bad;
                        }
                }
        } else {
                /*
                 * Dag Card
                 */
#ifdef HAVE_DAG_API
                /*
                 * We have DAG support.
                 */
                LONG    status;
                HKEY    dagkey;
                DWORD   lptype;
                DWORD   lpcbdata;
                int             postype = 0;
                char    keyname[512];

                snprintf(keyname, sizeof(keyname), "%s\\CardParams\\%s",
                        "SYSTEM\\CurrentControlSet\\Services\\DAG",
                        strstr(_strlwr(p->opt.device), "dag"));
                do
                {
                        status = RegOpenKeyEx(HKEY_LOCAL_MACHINE, keyname, 0, KEY_READ, &dagkey);
                        if(status != ERROR_SUCCESS)
                                break;

                        status = RegQueryValueEx(dagkey,
                                "PosType",
                                NULL,
                                &lptype,
                                (char*)&postype,
                                &lpcbdata);

                        if(status != ERROR_SUCCESS)
                        {
                                postype = 0;
                        }

                        RegCloseKey(dagkey);
                }
                while(FALSE);


                p->snapshot = PacketSetSnapLen(pw->adapter, p->snapshot);

                /* Set the length of the FCS associated to any packet. This value
                 * will be subtracted to the packet length */
                pw->dag_fcs_bits = pw->adapter->DagFcsLen;
#else /* HAVE_DAG_API */
                /*
                 * No DAG support.
                 */
                goto bad;
#endif /* HAVE_DAG_API */
        }

        /*
         * If there's no filter program installed, there's
         * no indication to the kernel of what the snapshot
         * length should be, so no snapshotting is done.
         *
         * Therefore, when we open the device, we install
         * an "accept everything" filter with the specified
         * snapshot length.
         */
        total_insn.code = (u_short)(BPF_RET | BPF_K);
        total_insn.jt = 0;
        total_insn.jf = 0;
        total_insn.k = p->snapshot;

        total_prog.bf_len = 1;
        total_prog.bf_insns = &total_insn;
        if (!PacketSetBpf(pw->adapter, &total_prog)) {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "PacketSetBpf");
                status = PCAP_ERROR;
                goto bad;
        }

        PacketSetReadTimeout(pw->adapter, p->opt.timeout);

        /* disable loopback capture if requested */
        if (p->opt.nocapture_local)
        {
                if (!PacketSetLoopbackBehavior(pw->adapter, NPF_DISABLE_LOOPBACK))
                {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "Unable to disable the capture of loopback packets.");
                        goto bad;
                }
        }

#ifdef HAVE_DAG_API
        if(pw->adapter->Flags & INFO_FLAG_DAG_CARD)
        {
                /* install dag specific handlers for read and setfilter */
                p->read_op = pcap_read_win32_dag;
                p->setfilter_op = pcap_setfilter_win32_dag;
        }
        else
        {
#endif /* HAVE_DAG_API */
                /* install traditional npf handlers for read and setfilter */
                p->read_op = pcap_read_npf;
                p->setfilter_op = pcap_setfilter_npf;
#ifdef HAVE_DAG_API
        }
#endif /* HAVE_DAG_API */
        p->setdirection_op = NULL;      /* Not implemented. */
            /* XXX - can this be implemented on some versions of Windows? */
        p->inject_op = pcap_inject_npf;
        p->set_datalink_op = NULL;      /* can't change data link type */
        p->getnonblock_op = pcap_getnonblock_npf;
        p->setnonblock_op = pcap_setnonblock_npf;
        p->stats_op = pcap_stats_npf;
        p->breakloop_op = pcap_breakloop_npf;
        p->stats_ex_op = pcap_stats_ex_npf;
        p->setbuff_op = pcap_setbuff_npf;
        p->setmode_op = pcap_setmode_npf;
        p->setmintocopy_op = pcap_setmintocopy_npf;
        p->getevent_op = pcap_getevent_npf;
        p->oid_get_request_op = pcap_oid_get_request_npf;
        p->oid_set_request_op = pcap_oid_set_request_npf;
        p->sendqueue_transmit_op = pcap_sendqueue_transmit_npf;
        p->setuserbuffer_op = pcap_setuserbuffer_npf;
        p->live_dump_op = pcap_live_dump_npf;
        p->live_dump_ended_op = pcap_live_dump_ended_npf;
        p->get_airpcap_handle_op = pcap_get_airpcap_handle_npf;
        p->cleanup_op = pcap_cleanup_npf;

        /*
         * XXX - this is only done because WinPcap supported
         * pcap_fileno() returning the hFile HANDLE from the
         * ADAPTER structure.  We make no general guarantees
         * that the caller can do anything useful with it.
         *
         * (Not that we make any general guarantee of that
         * sort on UN*X, either, anymore, given that not
         * all capture devices are regular OS network
         * interfaces.)
         */
        p->handle = pw->adapter->hFile;

        return (status);
bad:
        pcap_cleanup_npf(p);
        return (PCAP_ERROR);
}

/*
* Check if rfmon mode is supported on the pcap_t for Windows systems.
*/
static int
pcap_can_set_rfmon_npf(pcap_t *p)
{
        return (PacketIsMonitorModeSupported(p->opt.device) == 1);
}

/*
 * Get a list of time stamp types.
 */
#ifdef HAVE_PACKET_GET_TIMESTAMP_MODES
static int
get_ts_types(const char *device, pcap_t *p, char *ebuf)
{
        char *device_copy = NULL;
        ADAPTER *adapter = NULL;
        ULONG num_ts_modes;
        /* Npcap 1.00 driver is buggy and will write 16 bytes regardless of
         * buffer size. Using a sufficient stack buffer avoids overflow and
         * avoids a heap allocation in most (currently all) cases.
         */
        ULONG ts_modes[4];
        BOOL ret;
        DWORD error = ERROR_SUCCESS;
        ULONG *modes = NULL;
        int status = 0;

        do {
                /*
                 * First, find out how many time stamp modes we have.
                 * To do that, we have to open the adapter.
                 *
                 * XXX - PacketOpenAdapter() takes a non-const pointer
                 * as an argument, so we make a copy of the argument and
                 * pass that to it.
                 */
                device_copy = strdup(device);
                if (device_copy == NULL) {
                        pcapint_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE, errno, "malloc");
                        status = -1;
                        break;
                }

                adapter = PacketOpenAdapter(device_copy);
                if (adapter == NULL)
                {
                        error = GetLastError();
                        /*
                         * If we can't open the device now, we won't be
                         * able to later, either.
                         *
                         * If the error is something that indicates
                         * that the device doesn't exist, or that they
                         * don't have permission to open the device - or
                         * perhaps that they don't have permission to get
                         * a list of devices, if PacketOpenAdapter() does
                         * that - the user will find that out when they try
                         * to activate the device; just return an empty
                         * list of time stamp types.
                         *
                         * Treating either of those as errors will, for
                         * example, cause "tcpdump -i <number>" to fail,
                         * because it first tries to pass the interface
                         * name to pcap_create() and pcap_activate(),
                         * in order to handle OSes where interfaces can
                         * have names that are just numbers (stand up
                         * and say hello, Linux!), and, if pcap_activate()
                         * fails with a "no such device" error, checks
                         * whether the interface name is a valid number
                         * and, if so, tries to use it as an index in
                         * the list of interfaces.
                         *
                         * That means pcap_create() must succeed even
                         * for interfaces that don't exist, with the
                         * failure occurring at pcap_activate() time.
                         */
                        if (error == ERROR_BAD_UNIT ||
                            error == ERROR_ACCESS_DENIED) {
                                p->tstamp_type_count = 0;
                                p->tstamp_type_list = NULL;
                                status = 0;
                        } else {
                                pcapint_fmt_errmsg_for_win32_err(ebuf,
                                    PCAP_ERRBUF_SIZE, error,
                                    "Error opening adapter");
                                status = -1;
                        }
                        break;
                }

                /*
                 * Get the total number of time stamp modes.
                 *
                 * The buffer for PacketGetTimestampModes() is
                 * a sequence of 1 or more ULONGs.  What's
                 * passed to PacketGetTimestampModes() should have
                 * the total number of ULONGs in the first ULONG;
                 * what's returned *from* PacketGetTimestampModes()
                 * has the total number of time stamp modes in
                 * the first ULONG.
                 *
                 * Yes, that means if there are N time stamp
                 * modes, the first ULONG should be set to N+1
                 * on input, and will be set to N on output.
                 *
                 * We first make a call to PacketGetTimestampModes()
                 * with a pointer to a single ULONG set to 1; the
                 * call should fail with ERROR_MORE_DATA (unless
                 * there are *no* modes, but that should never
                 * happen), and that ULONG should be set to the
                 * number of modes.
                 */
                ts_modes[0] = sizeof(ts_modes) / sizeof(ULONG);
                ret = PacketGetTimestampModes(adapter, ts_modes);
                if (!ret) {
                        /*
                         * OK, it failed.  Did it fail with
                         * ERROR_MORE_DATA?
                         */
                        error = GetLastError();
                        if (error != ERROR_MORE_DATA) {
                                /*
                                 * No, did it fail with ERROR_INVALID_FUNCTION?
                                 */
                                if (error == ERROR_INVALID_FUNCTION) {
                                        /*
                                         * This is probably due to
                                         * the driver with which Packet.dll
                                         * communicates being older, or
                                         * being a WinPcap driver, so
                                         * that it doesn't support
                                         * BIOCGTIMESTAMPMODES.
                                         *
                                         * Tell the user to try uninstalling
                                         * Npcap - and WinPcap if installed -
                                         * and re-installing it, to flush
                                         * out all older drivers.
                                         */
                                        snprintf(ebuf, PCAP_ERRBUF_SIZE,
                                            "PacketGetTimestampModes() failed with ERROR_INVALID_FUNCTION; try uninstalling Npcap, and WinPcap if installed, and re-installing it from npcap.com");
                                        status = -1;
                                        break;
                                }

                                /*
                                 * No, some other error.  Fail.
                                 */
                                pcapint_fmt_errmsg_for_win32_err(ebuf,
                                    PCAP_ERRBUF_SIZE, error,
                                    "Error calling PacketGetTimestampModes");
                                status = -1;
                                break;
                        }

                        /*
                         * Yes, so we now know how many types to fetch.
                         *
                         * The buffer needs to have one ULONG for the
                         * count and num_ts_modes ULONGs for the
                         * num_ts_modes time stamp types.
                         */
                        num_ts_modes = ts_modes[0];
                        modes = (ULONG *)malloc((1 + num_ts_modes) * sizeof(ULONG));
                        if (modes == NULL) {
                                /* Out of memory. */
                                pcapint_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE, errno, "malloc");
                                status = -1;
                                break;
                        }
                        modes[0] = 1 + num_ts_modes;
                        if (!PacketGetTimestampModes(adapter, modes)) {
                                pcapint_fmt_errmsg_for_win32_err(ebuf,
                                                PCAP_ERRBUF_SIZE, GetLastError(),
                                                "Error calling PacketGetTimestampModes");
                                status = -1;
                                break;
                        }
                        if (modes[0] != num_ts_modes) {
                                snprintf(ebuf, PCAP_ERRBUF_SIZE,
                                                "First PacketGetTimestampModes() call gives %lu modes, second call gives %lu modes",
                                                num_ts_modes, modes[0]);
                                status = -1;
                                break;
                        }
                }
                else {
                        modes = ts_modes;
                        num_ts_modes = ts_modes[0];
                }

                /* If the driver reports no modes supported *and*
                 * ERROR_MORE_DATA, something is seriously wrong.
                 * We *could* ignore the error and continue without supporting
                 * settable timestamp modes, but that would hide a bug.
                 */
                if (modes[0] == 0) {
                        snprintf(ebuf, PCAP_ERRBUF_SIZE,
                            "PacketGetTimestampModes() reports 0 modes supported.");
                        status = -1;
                        break;
                }

                /*
                 * Allocate a buffer big enough for
                 * PCAP_TSTAMP_HOST (default) plus
                 * the explicitly specified modes.
                 */
                p->tstamp_type_list = malloc((1 + num_ts_modes) * sizeof(u_int));
                if (p->tstamp_type_list == NULL) {
                        pcapint_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE, errno, "malloc");
                        status = -1;
                        break;
                }
                u_int num_ts_types = 0;
                p->tstamp_type_list[num_ts_types] =
                    PCAP_TSTAMP_HOST;
                num_ts_types++;
                for (ULONG i = 0; i < num_ts_modes; i++) {
                        switch (modes[i + 1]) {

                        case TIMESTAMPMODE_SINGLE_SYNCHRONIZATION:
                                /*
                                 * Better than low-res,
                                 * but *not* synchronized
                                 * with the OS clock.
                                 */
                                p->tstamp_type_list[num_ts_types] =
                                    PCAP_TSTAMP_HOST_HIPREC_UNSYNCED;
                                num_ts_types++;
                                break;

                        case TIMESTAMPMODE_QUERYSYSTEMTIME:
                                /*
                                 * Low-res, but synchronized
                                 * with the OS clock.
                                 */
                                p->tstamp_type_list[num_ts_types] =
                                    PCAP_TSTAMP_HOST_LOWPREC;
                                num_ts_types++;
                                break;

                        case TIMESTAMPMODE_QUERYSYSTEMTIME_PRECISE:
                                /*
                                 * High-res, and synchronized
                                 * with the OS clock.
                                 */
                                p->tstamp_type_list[num_ts_types] =
                                    PCAP_TSTAMP_HOST_HIPREC;
                                num_ts_types++;
                                break;

                        default:
                                /*
                                 * Unknown, so we can't
                                 * report it.
                                 */
                                break;
                        }
                }
                p->tstamp_type_count = num_ts_types;
        } while (0);

        /* Clean up temporary allocations */
        if (device_copy != NULL) {
                free(device_copy);
        }
        if (modes != NULL && modes != ts_modes) {
                free(modes);
        }
        if (adapter != NULL) {
                PacketCloseAdapter(adapter);
        }

        return status;
}
#else /* HAVE_PACKET_GET_TIMESTAMP_MODES */
static int
get_ts_types(const char *device _U_, pcap_t *p _U_, char *ebuf _U_)
{
        /*
         * Nothing to fetch, so it always "succeeds".
         */
        return 0;
}
#endif /* HAVE_PACKET_GET_TIMESTAMP_MODES */

pcap_t *
pcapint_create_interface(const char *device _U_, char *ebuf)
{
        pcap_t *p;

        p = PCAP_CREATE_COMMON(ebuf, struct pcap_win);
        if (p == NULL)
                return (NULL);

        p->activate_op = pcap_activate_npf;
        p->can_set_rfmon_op = pcap_can_set_rfmon_npf;

        if (get_ts_types(device, p, ebuf) == -1) {
                pcap_close(p);
                return (NULL);
        }
        return (p);
}

static int
pcap_setfilter_npf(pcap_t *p, struct bpf_program *fp)
{
        struct pcap_win *pw = p->priv;

        if(PacketSetBpf(pw->adapter,fp)==FALSE){
                /*
                 * Kernel filter not installed.
                 *
                 * XXX - we don't know whether this failed because:
                 *
                 *  the kernel rejected the filter program as invalid,
                 *  in which case we should fall back on userland
                 *  filtering;
                 *
                 *  the kernel rejected the filter program as too big,
                 *  in which case we should again fall back on
                 *  userland filtering;
                 *
                 *  there was some other problem, in which case we
                 *  should probably report an error.
                 *
                 * For NPF devices, the Win32 status will be
                 * STATUS_INVALID_DEVICE_REQUEST for invalid
                 * filters, but I don't know what it'd be for
                 * other problems, and for some other devices
                 * it might not be set at all.
                 *
                 * So we just fall back on userland filtering in
                 * all cases.
                 */

                /*
                 * pcapint_install_bpf_program() validates the program.
                 *
                 * XXX - what if we already have a filter in the kernel?
                 */
                if (pcapint_install_bpf_program(p, fp) < 0)
                        return (-1);
                pw->filtering_in_kernel = 0;    /* filtering in userland */
                return (0);
        }

        /*
         * It worked.
         */
        pw->filtering_in_kernel = 1;    /* filtering in the kernel */

        /*
         * Discard any previously-received packets, as they might have
         * passed whatever filter was formerly in effect, but might
         * not pass this filter (BIOCSETF discards packets buffered
         * in the kernel, so you can lose packets in any case).
         */
        p->cc = 0;
        return (0);
}

/*
 * We filter at user level, since the kernel driver doesn't process the packets
 */
static int
pcap_setfilter_win32_dag(pcap_t *p, struct bpf_program *fp) {

        if(!fp)
        {
                pcapint_strlcpy(p->errbuf, "setfilter: No filter specified", sizeof(p->errbuf));
                return (-1);
        }

        /* Install a user level filter */
        if (pcapint_install_bpf_program(p, fp) < 0)
                return (-1);

        return (0);
}

static int
pcap_getnonblock_npf(pcap_t *p)
{
        struct pcap_win *pw = p->priv;

        /*
         * XXX - if there were a PacketGetReadTimeout() call, we
         * would use it, and return 1 if the timeout is -1
         * and 0 otherwise.
         */
        return (pw->nonblock);
}

static int
pcap_setnonblock_npf(pcap_t *p, int nonblock)
{
        struct pcap_win *pw = p->priv;
        int newtimeout;

        if (nonblock) {
                /*
                 * Set the packet buffer timeout to -1 for non-blocking
                 * mode.
                 */
                newtimeout = -1;
        } else {
                /*
                 * Restore the timeout set when the device was opened.
                 * (Note that this may be -1, in which case we're not
                 * really leaving non-blocking mode.  However, although
                 * the timeout argument to pcap_set_timeout() and
                 * pcap_open_live() is an int, you're not supposed to
                 * supply a negative value, so that "shouldn't happen".)
                 */
                newtimeout = p->opt.timeout;
        }
        if (!PacketSetReadTimeout(pw->adapter, newtimeout)) {
                pcapint_fmt_errmsg_for_win32_err(p->errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "PacketSetReadTimeout");
                return (-1);
        }
        pw->nonblock = (newtimeout == -1);
        return (0);
}

static int
pcap_add_if_npf(pcap_if_list_t *devlistp, char *name, bpf_u_int32 flags,
    const char *description, char *errbuf)
{
        pcap_if_t *curdev;
        npf_if_addr if_addrs[MAX_NETWORK_ADDRESSES];
        LONG if_addr_size;
        int res = 0;

        if_addr_size = MAX_NETWORK_ADDRESSES;

        /*
         * Add an entry for this interface, with no addresses.
         */
        curdev = pcapint_add_dev(devlistp, name, flags, description, errbuf);
        if (curdev == NULL) {
                /*
                 * Failure.
                 */
                return (-1);
        }

        /*
         * Get the list of addresses for the interface.
         */
        if (!PacketGetNetInfoEx((void *)name, if_addrs, &if_addr_size)) {
                /*
                 * Failure.
                 *
                 * We don't return an error, because this can happen with
                 * NdisWan interfaces, and we want to supply them even
                 * if we can't supply their addresses.
                 *
                 * We return an entry with an empty address list.
                 */
                return (0);
        }

        /*
         * Now add the addresses.
         */
        while (if_addr_size-- > 0) {
                /*
                 * "curdev" is an entry for this interface; add an entry for
                 * this address to its list of addresses.
                 */
                res = pcapint_add_addr_to_dev(curdev,
                    (struct sockaddr *)&if_addrs[if_addr_size].IPAddress,
                    sizeof (struct sockaddr_storage),
                    (struct sockaddr *)&if_addrs[if_addr_size].SubnetMask,
                    sizeof (struct sockaddr_storage),
                    (struct sockaddr *)&if_addrs[if_addr_size].Broadcast,
                    sizeof (struct sockaddr_storage),
                    NULL,
                    0,
                    errbuf);
                if (res == -1) {
                        /*
                         * Failure.
                         */
                        break;
                }
        }

        return (res);
}

static int
get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
{
        char *name_copy;
        ADAPTER *adapter;
        int status;
        size_t len;
        NDIS_HARDWARE_STATUS hardware_status;
#ifdef OID_GEN_PHYSICAL_MEDIUM
        NDIS_PHYSICAL_MEDIUM phys_medium;
        bpf_u_int32 gen_physical_medium_oids[] = {
  #ifdef OID_GEN_PHYSICAL_MEDIUM_EX
                OID_GEN_PHYSICAL_MEDIUM_EX,
  #endif
                OID_GEN_PHYSICAL_MEDIUM
        };
#define N_GEN_PHYSICAL_MEDIUM_OIDS      (sizeof gen_physical_medium_oids / sizeof gen_physical_medium_oids[0])
        size_t i;
#endif /* OID_GEN_PHYSICAL_MEDIUM */
#ifdef OID_GEN_LINK_STATE
        NDIS_LINK_STATE link_state;
#endif
        int connect_status;

        if (*flags & PCAP_IF_LOOPBACK) {
                /*
                 * Loopback interface, so the connection status doesn't
                 * apply. and it's not wireless (or wired, for that
                 * matter...).  We presume it's up and running.
                 */
                *flags |= PCAP_IF_UP | PCAP_IF_RUNNING | PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
                return (0);
        }

        /*
         * We need to open the adapter to get this information.
         *
         * XXX - PacketOpenAdapter() takes a non-const pointer
         * as an argument, so we make a copy of the argument and
         * pass that to it.
         */
        name_copy = strdup(name);
        adapter = PacketOpenAdapter(name_copy);
        free(name_copy);
        if (adapter == NULL) {
                /*
                 * Give up; if they try to open this device, it'll fail.
                 */
                return (0);
        }

#ifdef HAVE_AIRPCAP_API
        /*
         * Airpcap.sys do not support the below 'OID_GEN_x' values.
         * Just set these flags (and none of the '*flags' entered with).
         */
        if (PacketGetAirPcapHandle(adapter)) {
                /*
                 * Must be "up" and "running" if the above if succeeded.
                 */
                *flags = PCAP_IF_UP | PCAP_IF_RUNNING;

                /*
                 * An airpcap device is a wireless device (duh!)
                 */
                *flags |= PCAP_IF_WIRELESS;

                /*
                 * A "network association state" makes no sense for airpcap.
                 */
                *flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
                PacketCloseAdapter(adapter);
                return (0);
        }
#endif

        /*
         * Get the hardware status, and derive "up" and "running" from
         * that.
         */
        len = sizeof (hardware_status);
        status = oid_get_request(adapter, OID_GEN_HARDWARE_STATUS,
            &hardware_status, &len, errbuf);
        if (status == 0) {
                switch (hardware_status) {

                case NdisHardwareStatusReady:
                        /*
                         * "Available and capable of sending and receiving
                         * data over the wire", so up and running.
                         */
                        *flags |= PCAP_IF_UP | PCAP_IF_RUNNING;
                        break;

                case NdisHardwareStatusInitializing:
                case NdisHardwareStatusReset:
                        /*
                         * "Initializing" or "Resetting", so up, but
                         * not running.
                         */
                        *flags |= PCAP_IF_UP;
                        break;

                case NdisHardwareStatusClosing:
                case NdisHardwareStatusNotReady:
                        /*
                         * "Closing" or "Not ready", so neither up nor
                         * running.
                         */
                        break;

                default:
                        /*
                         * Unknown.
                         */
                        break;
                }
        } else {
                /*
                 * Can't get the hardware status, so assume both up and
                 * running.
                 */
                *flags |= PCAP_IF_UP | PCAP_IF_RUNNING;
        }

        /*
         * Get the network type.
         */
#ifdef OID_GEN_PHYSICAL_MEDIUM
        /*
         * Try the OIDs we have for this, in order.
         */
        for (i = 0; i < N_GEN_PHYSICAL_MEDIUM_OIDS; i++) {
                len = sizeof (phys_medium);
                status = oid_get_request(adapter, gen_physical_medium_oids[i],
                    &phys_medium, &len, errbuf);
                if (status == 0) {
                        /*
                         * Success.
                         */
                        break;
                }
                /*
                 * Failed.  We can't determine whether it failed
                 * because that particular OID isn't supported
                 * or because some other problem occurred, so we
                 * just drive on and try the next OID.
                 */
        }
        if (status == 0) {
                /*
                 * We got the physical medium.
                 *
                 * XXX - we might want to check for NdisPhysicalMediumWiMax
                 * and NdisPhysicalMediumNative802_15_4 being
                 * part of the enum, and check for those in the "wireless"
                 * case.
                 */
DIAG_OFF_ENUM_SWITCH
                switch (phys_medium) {

                case NdisPhysicalMediumWirelessLan:
                case NdisPhysicalMediumWirelessWan:
                case NdisPhysicalMediumNative802_11:
                case NdisPhysicalMediumBluetooth:
                case NdisPhysicalMediumUWB:
                case NdisPhysicalMediumIrda:
                        /*
                         * Wireless.
                         */
                        *flags |= PCAP_IF_WIRELESS;
                        break;

                default:
                        /*
                         * Not wireless or unknown
                         */
                        break;
                }
DIAG_ON_ENUM_SWITCH
        }
#endif

        /*
         * Get the connection status.
         */
#ifdef OID_GEN_LINK_STATE
        len = sizeof(link_state);
        status = oid_get_request(adapter, OID_GEN_LINK_STATE, &link_state,
            &len, errbuf);
        if (status == 0) {
                /*
                 * NOTE: this also gives us the receive and transmit
                 * link state.
                 */
                switch (link_state.MediaConnectState) {

                case MediaConnectStateConnected:
                        /*
                         * It's connected.
                         */
                        *flags |= PCAP_IF_CONNECTION_STATUS_CONNECTED;
                        break;

                case MediaConnectStateDisconnected:
                        /*
                         * It's disconnected.
                         */
                        *flags |= PCAP_IF_CONNECTION_STATUS_DISCONNECTED;
                        break;

                case MediaConnectStateUnknown:
                default:
                        /*
                         * It's unknown whether it's connected or not.
                         */
                        break;
                }
        }
#else
        /*
         * OID_GEN_LINK_STATE isn't supported because it's not in our SDK.
         */
        status = -1;
#endif
        if (status == -1) {
                /*
                 * OK, OID_GEN_LINK_STATE didn't work, try
                 * OID_GEN_MEDIA_CONNECT_STATUS.
                 */
                status = oid_get_request(adapter, OID_GEN_MEDIA_CONNECT_STATUS,
                    &connect_status, &len, errbuf);
                if (status == 0) {
                        switch (connect_status) {

                        case NdisMediaStateConnected:
                                /*
                                 * It's connected.
                                 */
                                *flags |= PCAP_IF_CONNECTION_STATUS_CONNECTED;
                                break;

                        case NdisMediaStateDisconnected:
                                /*
                                 * It's disconnected.
                                 */
                                *flags |= PCAP_IF_CONNECTION_STATUS_DISCONNECTED;
                                break;
                        }
                }
        }
        PacketCloseAdapter(adapter);
        return (0);
}

int
pcapint_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
{
        int ret = 0;
        const char *desc;
        char *AdaptersName;
        ULONG NameLength;
        char *name;

        /*
         * Find out how big a buffer we need.
         *
         * This call should always return FALSE; if the error is
         * ERROR_INSUFFICIENT_BUFFER, NameLength will be set to
         * the size of the buffer we need, otherwise there's a
         * problem, and NameLength should be set to 0.
         *
         * It shouldn't require NameLength to be set, but,
         * at least as of WinPcap 4.1.3, it checks whether
         * NameLength is big enough before it checks for a
         * NULL buffer argument, so, while it'll still do
         * the right thing if NameLength is uninitialized and
         * whatever junk happens to be there is big enough
         * (because the pointer argument will be null), it's
         * still reading an uninitialized variable.
         */
        NameLength = 0;
        if (!PacketGetAdapterNames(NULL, &NameLength))
        {
                DWORD last_error = GetLastError();

                if (last_error != ERROR_INSUFFICIENT_BUFFER)
                {
                        pcapint_fmt_errmsg_for_win32_err(errbuf, PCAP_ERRBUF_SIZE,
                            last_error, "PacketGetAdapterNames");
                        return (-1);
                }
        }

        if (NameLength <= 0)
                return 0;
        AdaptersName = (char*) malloc(NameLength);
        if (AdaptersName == NULL)
        {
                snprintf(errbuf, PCAP_ERRBUF_SIZE, "Cannot allocate enough memory to list the adapters.");
                return (-1);
        }

        if (!PacketGetAdapterNames(AdaptersName, &NameLength)) {
                pcapint_fmt_errmsg_for_win32_err(errbuf, PCAP_ERRBUF_SIZE,
                    GetLastError(), "PacketGetAdapterNames");
                free(AdaptersName);
                return (-1);
        }

        /*
         * "PacketGetAdapterNames()" returned a list of
         * null-terminated ASCII interface name strings,
         * terminated by a null string, followed by a list
         * of null-terminated ASCII interface description
         * strings, terminated by a null string.
         * This means there are two ASCII nulls at the end
         * of the first list.
         *
         * Find the end of the first list; that's the
         * beginning of the second list.
         */
        desc = &AdaptersName[0];
        while (*desc != '\0' || *(desc + 1) != '\0')
                desc++;

        /*
         * Found it - "desc" points to the first of the two
         * nulls at the end of the list of names, so the
         * first byte of the list of descriptions is two bytes
         * after it.
         */
        desc += 2;

        /*
         * Loop over the elements in the first list.
         */
        name = &AdaptersName[0];
        while (*name != '\0') {
                bpf_u_int32 flags = 0;

#ifdef HAVE_AIRPCAP_API
                /*
                 * Is this an AirPcap device?
                 * If so, ignore it; it'll get added later, by the
                 * AirPcap code.
                 */
                if (device_is_airpcap(name, errbuf) == 1) {
                        name += strlen(name) + 1;
                        desc += strlen(desc) + 1;
                        continue;
                }
#endif

#ifdef HAVE_PACKET_IS_LOOPBACK_ADAPTER
                /*
                 * Is this a loopback interface?
                 */
                if (PacketIsLoopbackAdapter(name)) {
                        /* Yes */
                        flags |= PCAP_IF_LOOPBACK;
                }
#endif
                /*
                 * Get additional flags.
                 */
                if (get_if_flags(name, &flags, errbuf) == -1) {
                        /*
                         * Failure.
                         */
                        ret = -1;
                        break;
                }

                /*
                 * Add an entry for this interface.
                 */
                if (pcap_add_if_npf(devlistp, name, flags, desc,
                    errbuf) == -1) {
                        /*
                         * Failure.
                         */
                        ret = -1;
                        break;
                }
                name += strlen(name) + 1;
                desc += strlen(desc) + 1;
        }

        free(AdaptersName);
        return (ret);
}

/*
 * 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.
 *
 * In the best of all possible worlds, this would be the same as on
 * UN*X, but there may be software that expects this to return a
 * full list of devices after the first device.
 */
#define ADAPTERSNAME_LEN        8192
char *
pcap_lookupdev(char *errbuf)
{
        DWORD dwVersion;
        DWORD dwWindowsMajorVersion;

        /*
         * 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);
        }

/* disable MSVC's GetVersion() deprecated warning here */
DIAG_OFF_DEPRECATION
        dwVersion = GetVersion();       /* get the OS version */
DIAG_ON_DEPRECATION
        dwWindowsMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));

        if (dwVersion >= 0x80000000 && dwWindowsMajorVersion >= 4) {
                /*
                 * Windows 95, 98, ME.
                 */
                ULONG NameLength = ADAPTERSNAME_LEN;
                static char AdaptersName[ADAPTERSNAME_LEN];

                if (PacketGetAdapterNames(AdaptersName,&NameLength) )
                        return (AdaptersName);
                else
                        return NULL;
        } else {
                /*
                 * Windows NT (NT 4.0 and later).
                 * Convert the names to Unicode for backward compatibility.
                 */
                ULONG NameLength = ADAPTERSNAME_LEN;
                static WCHAR AdaptersName[ADAPTERSNAME_LEN];
                size_t BufferSpaceLeft;
                char *tAstr;
                WCHAR *Unameptr;
                char *Adescptr;
                size_t namelen, i;
                WCHAR *TAdaptersName = (WCHAR*)malloc(ADAPTERSNAME_LEN * sizeof(WCHAR));
                int NAdapts = 0;

                if(TAdaptersName == NULL)
                {
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "memory allocation failure");
                        return NULL;
                }

                if ( !PacketGetAdapterNames((PTSTR)TAdaptersName,&NameLength) )
                {
                        pcapint_fmt_errmsg_for_win32_err(errbuf, PCAP_ERRBUF_SIZE,
                            GetLastError(), "PacketGetAdapterNames");
                        free(TAdaptersName);
                        return NULL;
                }


                BufferSpaceLeft = ADAPTERSNAME_LEN * sizeof(WCHAR);
                tAstr = (char*)TAdaptersName;
                Unameptr = AdaptersName;

                /*
                 * Convert the device names to Unicode into AdapterName.
                 */
                do {
                        /*
                         * Length of the name, including the terminating
                         * NUL.
                         */
                        namelen = strlen(tAstr) + 1;

                        /*
                         * Do we have room for the name in the Unicode
                         * buffer?
                         */
                        if (BufferSpaceLeft < namelen * sizeof(WCHAR)) {
                                /*
                                 * No.
                                 */
                                goto quit;
                        }
                        BufferSpaceLeft -= namelen * sizeof(WCHAR);

                        /*
                         * Copy the name, converting ASCII to Unicode.
                         * namelen includes the NUL, so we copy it as
                         * well.
                         */
                        for (i = 0; i < namelen; i++)
                                *Unameptr++ = *tAstr++;

                        /*
                         * Count this adapter.
                         */
                        NAdapts++;
                } while (namelen != 1);

                /*
                 * Copy the descriptions, but don't convert them from
                 * ASCII to Unicode.
                 */
                Adescptr = (char *)Unameptr;
                while(NAdapts--)
                {
                        size_t desclen;

                        desclen = strlen(tAstr) + 1;

                        /*
                         * Do we have room for the name in the Unicode
                         * buffer?
                         */
                        if (BufferSpaceLeft < desclen) {
                                /*
                                 * No.
                                 */
                                goto quit;
                        }

                        /*
                         * Just copy the ASCII string.
                         * namelen includes the NUL, so we copy it as
                         * well.
                         */
                        memcpy(Adescptr, tAstr, desclen);
                        Adescptr += desclen;
                        tAstr += desclen;
                        BufferSpaceLeft -= desclen;
                }

        quit:
                free(TAdaptersName);
                return (char *)(AdaptersName);
        }
}

/*
 * We can't use the same code that we use on UN*X, as that's doing
 * UN*X-specific calls.
 *
 * 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.
 */
int
pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp,
    char *errbuf)
{
        /*
         * We need only the first IPv4 address, so we must scan the array returned by PacketGetNetInfo()
         * in order to skip non IPv4 (i.e. IPv6 addresses)
         */
        npf_if_addr if_addrs[MAX_NETWORK_ADDRESSES];
        LONG if_addr_size = MAX_NETWORK_ADDRESSES;
        struct sockaddr_in *t_addr;
        LONG i;

        if (!PacketGetNetInfoEx((void *)device, if_addrs, &if_addr_size)) {
                *netp = *maskp = 0;
                return (0);
        }

        for(i = 0; i < if_addr_size; i++)
        {
                if(if_addrs[i].IPAddress.ss_family == AF_INET)
                {
                        t_addr = (struct sockaddr_in *) &(if_addrs[i].IPAddress);
                        *netp = t_addr->sin_addr.S_un.S_addr;
                        t_addr = (struct sockaddr_in *) &(if_addrs[i].SubnetMask);
                        *maskp = t_addr->sin_addr.S_un.S_addr;

                        *netp &= *maskp;
                        return (0);
                }

        }

        *netp = *maskp = 0;
        return (0);
}

static const char *pcap_lib_version_string;

#ifdef HAVE_VERSION_H
/*
 * libpcap being built for Windows, as part of a WinPcap/Npcap source
 * tree.  Include version.h from that source tree to get the WinPcap/Npcap
 * version.
 *
 * XXX - it'd be nice if we could somehow generate the WinPcap/Npcap version
 * number when building as part of WinPcap/Npcap.  (It'd be nice to do so
 * for the packet.dll version number as well.)
 */
#include "../../version.h"

static const char pcap_version_string[] =
        WINPCAP_PRODUCT_NAME " version " WINPCAP_VER_STRING ", based on " PCAP_VERSION_STRING;

const char *
pcap_lib_version(void)
{
        if (pcap_lib_version_string == NULL) {
                /*
                 * Generate the version string.
                 */
                const char *packet_version_string = PacketGetVersion();

                if (strcmp(WINPCAP_VER_STRING, packet_version_string) == 0) {
                        /*
                         * WinPcap/Npcap version string and packet.dll version
                         * string are the same; just report the WinPcap/Npcap
                         * version.
                         */
                        pcap_lib_version_string = pcap_version_string;
                } else {
                        /*
                         * WinPcap/Npcap version string and packet.dll version
                         * string are different; that shouldn't be the
                         * case (the two libraries should come from the
                         * same version of WinPcap/Npcap), so we report both
                         * versions.
                         */
                        char *full_pcap_version_string;

                        if (pcapint_asprintf(&full_pcap_version_string,
                            WINPCAP_PRODUCT_NAME " version " WINPCAP_VER_STRING " (packet.dll version %s), based on " PCAP_VERSION_STRING,
                            packet_version_string) != -1) {
                                /* Success */
                                pcap_lib_version_string = full_pcap_version_string;
                        }
                }
        }
        return (pcap_lib_version_string);
}

#else /* HAVE_VERSION_H */

/*
 * libpcap being built for Windows, not as part of a WinPcap/Npcap source
 * tree.
 */
const char *
pcap_lib_version(void)
{
        if (pcap_lib_version_string == NULL) {
                /*
                 * Generate the version string.  Report the packet.dll
                 * version.
                 */
                char *full_pcap_version_string;

                if (pcapint_asprintf(&full_pcap_version_string,
                    PCAP_VERSION_STRING " (packet.dll version %s)",
                    PacketGetVersion()) != -1) {
                        /* Success */
                        pcap_lib_version_string = full_pcap_version_string;
                }
        }
        return (pcap_lib_version_string);
}
#endif /* HAVE_VERSION_H */