/* capture_wpcap_packet.c
 * WinPcap-specific interfaces for low-level information (packet.dll).
 * We load WinPcap at run
 * time, so that we only need one Wireshark binary and one TShark binary
 * for Windows, regardless of whether WinPcap is installed or not.
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 2001 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#if defined HAVE_LIBPCAP && defined _WIN32

#include <glib.h>
#include <gmodule.h>

#include "wspcap.h"

/* XXX - yes, I know, I should move cppmagic.h to a generic location. */
#include "tools/lemon/cppmagic.h"

#include <epan/value_string.h>

#include <windowsx.h>
#include <Ntddndis.h>

#include "caputils/capture_wpcap_packet.h"
#include <wsutil/file_util.h>

#include <Packet32.h>

gboolean has_wpacket = FALSE;

/* This module will use the PacketRequest function in packet.dll (coming with WinPcap) to "directly" access
 * the Win32 NDIS network driver(s) and ask for various values (status, statistics, ...).
 *
 * Unfortunately, the definitions required for this are not available through the usual windows header files,
 * but require the Windows "Device Driver Kit" which is not available for free :-(
 *
 *
 *
 * Fortunately, the definitions needed to access the various NDIS values are available from various OSS projects:
 * - WinPcap in Ntddndis.h
 * - Ndiswrapper in driver/ndis.h and driver/iw_ndis.h
 * - cygwin (MingW?) in usr/include/w32api/ddk/ndis.h and ntddndis.h
 * - FreeBSD (netperf)
 */

/* The description of the NDIS driver API is available at:
 * https://docs.microsoft.com/en-us/windows-hardware/drivers/network/ndis-core-functionality2
 */

/* Some more interesting links:
 * https://sourceforge.net/projects/ndiswrapper/
 * http://www.osronline.com/lists_archive/windbg/thread521.html
 * http://cvs.sourceforge.net/viewcvs.py/mingw/w32api/include/ddk/ndis.h?view=markup
 * http://cvs.sourceforge.net/viewcvs.py/mingw/w32api/include/ddk/ntddndis.h?view=markup
 */



/******************************************************************************************************************************/
/* stuff to load WinPcap's packet.dll and the functions required from it */

static PCHAR     (*p_PacketGetVersion) (void);
static LPADAPTER (*p_PacketOpenAdapter) (char *adaptername);
static void      (*p_PacketCloseAdapter) (LPADAPTER);
static int       (*p_PacketRequest) (LPADAPTER, int, void *);

typedef struct {
    const char  *name;
    gpointer    *ptr;
    gboolean    optional;
} symbol_table_t;

#define SYM(x, y)   { G_STRINGIFY(x) , (gpointer) &CONCAT(p_,x), y }

void
wpcap_packet_load(void)
{

    /* These are the symbols I need or want from packet.dll */
    static const symbol_table_t symbols[] = {
        SYM(PacketGetVersion, FALSE),
        SYM(PacketOpenAdapter, FALSE),
        SYM(PacketCloseAdapter, FALSE),
        SYM(PacketRequest, FALSE),
        { NULL, NULL, FALSE }
    };

    GModule     *wh; /* wpcap handle */
    const symbol_table_t    *sym;

    wh = ws_module_open("packet.dll", 0);

    if (!wh) {
        return;
    }

    sym = symbols;
    while (sym->name) {
        if (!g_module_symbol(wh, sym->name, sym->ptr)) {
            if (sym->optional) {
                /*
                 * We don't care if it's missing; we just
                 * don't use it.
                 */
                *sym->ptr = NULL;
            } else {
                /*
                 * We require this symbol.
                 */
                return;
            }
        }
        sym++;
    }

    has_wpacket = TRUE;
}



/******************************************************************************************************************************/
/* functions to access the NDIS driver values */


/* get dll version */
char *
wpcap_packet_get_version(void)
{
    if(!has_wpacket) {
        return NULL;
    }
    return p_PacketGetVersion();
}


/* open the interface */
void *
wpcap_packet_open(char *if_name)
{
    LPADAPTER   adapter;

    g_assert(has_wpacket);
    adapter = p_PacketOpenAdapter(if_name);

    return adapter;
}


/* close the interface */
void
wpcap_packet_close(void *adapter)
{

    g_assert(has_wpacket);
    p_PacketCloseAdapter(adapter);
}


/* do a packet request call */
int
wpcap_packet_request(void *adapter, ULONG Oid, int set, char *value, unsigned int *length)
{
    BOOLEAN    Status;
    ULONG      IoCtlBufferLength=(sizeof(PACKET_OID_DATA) + (*length) - 1);
    PPACKET_OID_DATA  OidData;


    g_assert(has_wpacket);

    if(p_PacketRequest == NULL) {
        g_warning("packet_request not available\n");
        return 0;
    }

    /* get a buffer suitable for PacketRequest() */
    OidData=GlobalAllocPtr(GMEM_MOVEABLE | GMEM_ZEROINIT,IoCtlBufferLength);
    if (OidData == NULL) {
        g_warning("GlobalAllocPtr failed for %u\n", IoCtlBufferLength);
        return 0;
    }

    OidData->Oid = Oid;
    OidData->Length = *length;
    memcpy(OidData->Data, value, *length);

    Status = p_PacketRequest(adapter, set, OidData);

    if(Status) {
        if(OidData->Length <= *length) {
            /* copy value from driver */
            memcpy(value, OidData->Data, OidData->Length);
            *length = OidData->Length;
        } else {
            /* the driver returned a value that is longer than expected (and longer than the given buffer) */
            g_warning("returned oid too long, Oid: 0x%x OidLen:%u MaxLen:%u", Oid, OidData->Length, *length);
            Status = FALSE;
        }
    }

    GlobalFreePtr (OidData);

    if(Status) {
        return 1;
    } else {
        return 0;
    }
}


/* get an UINT value using the packet request call */
int
wpcap_packet_request_uint(void *adapter, ULONG Oid, UINT *value)
{
    BOOLEAN     Status;
    int         length = sizeof(UINT);


    Status = wpcap_packet_request(adapter, Oid, FALSE /* !set */, (char *) value, &length);
    if(Status && length == sizeof(UINT)) {
        return 1;
    } else {
        return 0;
    }
}


/* get an ULONG value using the NDIS packet request call */
int
wpcap_packet_request_ulong(void *adapter, ULONG Oid, ULONG *value)
{
    BOOLEAN     Status;
    int         length = sizeof(ULONG);


    Status = wpcap_packet_request(adapter, Oid, FALSE /* !set */, (char *) value, &length);
    if(Status && length == sizeof(ULONG)) {
        return 1;
    } else {
        return 0;
    }
}


#else /* HAVE_LIBPCAP && _WIN32 */

void
wpcap_packet_load(void)
{
    return;
}

#endif /* HAVE_LIBPCAP */

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * ex: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */