windivert.h

/*
 * windivert.h
 * (C) 2018, all rights reserved,
 *
 * This file is part of WinDivert.
 *
 * WinDivert is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * WinDivert is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#ifndef __WINDIVERT_H
#define __WINDIVERT_H

#ifndef WINDIVERT_KERNEL
#include <windows.h>
#endif      /* WINDIVERT_KERNEL */

#ifndef WINDIVERTEXPORT
#define WINDIVERTEXPORT     __declspec(dllimport)
#endif      /* WINDIVERTEXPORT */

#ifdef __MINGW32__
#define __in
#define __in_opt
#define __out
#define __out_opt
#define __inout
#define __inout_opt
#include <stdint.h>
#define INT8    int8_t
#define UINT8   uint8_t
#define INT16   int16_t
#define UINT16  uint16_t
#define INT32   int32_t
#define UINT32  uint32_t
#define INT64   int64_t
#define UINT64  uint64_t
#endif      /* __MINGW32__ */

#ifdef __cplusplus
extern "C" {
#endif

    /****************************************************************************/
    /* WINDIVERT API                                                            */
    /****************************************************************************/

    /*
     * Divert address.
     */
    typedef struct
    {
        INT64  Timestamp;                   /* Packet's timestamp. */
        UINT32 IfIdx;                       /* Packet's interface index. */
        UINT32 SubIfIdx;                    /* Packet's sub-interface index. */
        UINT8  Direction : 1;                 /* Packet's direction. */
        UINT8  Loopback : 1;                  /* Packet is loopback? */
        UINT8  Impostor : 1;                  /* Packet is impostor? */
        UINT8  PseudoIPChecksum : 1;          /* Packet has pseudo IPv4 checksum? */
        UINT8  PseudoTCPChecksum : 1;         /* Packet has pseudo TCP checksum? */
        UINT8  PseudoUDPChecksum : 1;         /* Packet has pseudo UDP checksum? */
        UINT8  Reserved : 2;
    } WINDIVERT_ADDRESS, * PWINDIVERT_ADDRESS;

#define WINDIVERT_DIRECTION_OUTBOUND    0
#define WINDIVERT_DIRECTION_INBOUND     1

    /*
     * Divert layers.
     */
    typedef enum
    {
        WINDIVERT_LAYER_NETWORK = 0,        /* Network layer. */
        WINDIVERT_LAYER_NETWORK_FORWARD = 1 /* Network layer (forwarded packets) */
    } WINDIVERT_LAYER, * PWINDIVERT_LAYER;

    /*
     * Divert flags.
     */
#define WINDIVERT_FLAG_SNIFF            1
#define WINDIVERT_FLAG_DROP             2
#define WINDIVERT_FLAG_DEBUG            4

     /*
      * Divert parameters.
      */
    typedef enum
    {
        WINDIVERT_PARAM_QUEUE_LEN = 0,     /* Packet queue length. */
        WINDIVERT_PARAM_QUEUE_TIME = 1,     /* Packet queue time. */
        WINDIVERT_PARAM_QUEUE_SIZE = 2      /* Packet queue size. */
    } WINDIVERT_PARAM, * PWINDIVERT_PARAM;
#define WINDIVERT_PARAM_MAX             WINDIVERT_PARAM_QUEUE_SIZE

#ifndef WINDIVERT_KERNEL

    /*
     * Open a WinDivert handle.
     */
    extern WINDIVERTEXPORT HANDLE WinDivertOpen(
        __in        const char* filter,
        __in        WINDIVERT_LAYER layer,
        __in        INT16 priority,
        __in        UINT64 flags);

    /*
     * Receive (read) a packet from a WinDivert handle.
     */
    extern WINDIVERTEXPORT BOOL WinDivertRecv(
        __in        HANDLE handle,
        __out       PVOID pPacket,
        __in        UINT packetLen,
        __out_opt   PWINDIVERT_ADDRESS pAddr,
        __out_opt   UINT* readLen);

    /*
     * Receive (read) a packet from a WinDivert handle.
     */
    extern WINDIVERTEXPORT BOOL WinDivertRecvEx(
        __in        HANDLE handle,
        __out       PVOID pPacket,
        __in        UINT packetLen,
        __in        UINT64 flags,
        __out_opt   PWINDIVERT_ADDRESS pAddr,
        __out_opt   UINT* readLen,
        __inout_opt LPOVERLAPPED lpOverlapped);

    /*
     * Send (write/inject) a packet to a WinDivert handle.
     */
    extern WINDIVERTEXPORT BOOL WinDivertSend(
        __in        HANDLE handle,
        __in        PVOID pPacket,
        __in        UINT packetLen,
        __in        PWINDIVERT_ADDRESS pAddr,
        __out_opt   UINT* writeLen);

    /*
     * Send (write/inject) a packet to a WinDivert handle.
     */
    extern WINDIVERTEXPORT BOOL WinDivertSendEx(
        __in        HANDLE handle,
        __in        PVOID pPacket,
        __in        UINT packetLen,
        __in        UINT64 flags,
        __in        PWINDIVERT_ADDRESS pAddr,
        __out_opt   UINT* writeLen,
        __inout_opt LPOVERLAPPED lpOverlapped);

    /*
     * Close a WinDivert handle.
     */
    extern WINDIVERTEXPORT BOOL WinDivertClose(
        __in        HANDLE handle);

    /*
     * Set a WinDivert handle parameter.
     */
    extern WINDIVERTEXPORT BOOL WinDivertSetParam(
        __in        HANDLE handle,
        __in        WINDIVERT_PARAM param,
        __in        UINT64 value);

    /*
     * Get a WinDivert handle parameter.
     */
    extern WINDIVERTEXPORT BOOL WinDivertGetParam(
        __in        HANDLE handle,
        __in        WINDIVERT_PARAM param,
        __out       UINT64* pValue);

#endif      /* WINDIVERT_KERNEL */

    /****************************************************************************/
    /* WINDIVERT HELPER API                                                     */
    /****************************************************************************/

    /*
     * IPv4/IPv6/ICMP/ICMPv6/TCP/UDP header definitions.
     */
    typedef struct
    {
        UINT8  HdrLength : 4;
        UINT8  Version : 4;
        UINT8  TOS;
        UINT16 Length;
        UINT16 Id;
        UINT16 FragOff0;
        UINT8  TTL;
        UINT8  Protocol;
        UINT16 Checksum;
        UINT32 SrcAddr;
        UINT32 DstAddr;
    } WINDIVERT_IPHDR, * PWINDIVERT_IPHDR;

#define WINDIVERT_IPHDR_GET_FRAGOFF(hdr)                    \
    (((hdr)->FragOff0) & 0xFF1F)
#define WINDIVERT_IPHDR_GET_MF(hdr)                         \
    ((((hdr)->FragOff0) & 0x0020) != 0)
#define WINDIVERT_IPHDR_GET_DF(hdr)                         \
    ((((hdr)->FragOff0) & 0x0040) != 0)
#define WINDIVERT_IPHDR_GET_RESERVED(hdr)                   \
    ((((hdr)->FragOff0) & 0x0080) != 0)

#define WINDIVERT_IPHDR_SET_FRAGOFF(hdr, val)               \
    do                                                      \
    {                                                       \
        (hdr)->FragOff0 = (((hdr)->FragOff0) & 0x00E0) |    \
            ((val) & 0xFF1F);                               \
    }                                                       \
    while (FALSE)
#define WINDIVERT_IPHDR_SET_MF(hdr, val)                    \
    do                                                      \
    {                                                       \
        (hdr)->FragOff0 = (((hdr)->FragOff0) & 0xFFDF) |    \
            (((val) & 0x0001) << 5);                        \
    }                                                       \
    while (FALSE)
#define WINDIVERT_IPHDR_SET_DF(hdr, val)                    \
    do                                                      \
    {                                                       \
        (hdr)->FragOff0 = (((hdr)->FragOff0) & 0xFFBF) |    \
            (((val) & 0x0001) << 6);                        \
    }                                                       \
    while (FALSE)
#define WINDIVERT_IPHDR_SET_RESERVED(hdr, val)              \
    do                                                      \
    {                                                       \
        (hdr)->FragOff0 = (((hdr)->FragOff0) & 0xFF7F) |    \
            (((val) & 0x0001) << 7);                        \
    }                                                       \
    while (FALSE)

    typedef struct
    {
        UINT8  TrafficClass0 : 4;
        UINT8  Version : 4;
        UINT8  FlowLabel0 : 4;
        UINT8  TrafficClass1 : 4;
        UINT16 FlowLabel1;
        UINT16 Length;
        UINT8  NextHdr;
        UINT8  HopLimit;
        UINT32 SrcAddr[4];
        UINT32 DstAddr[4];
    } WINDIVERT_IPV6HDR, * PWINDIVERT_IPV6HDR;

#define WINDIVERT_IPV6HDR_GET_TRAFFICCLASS(hdr)             \
    ((((hdr)->TrafficClass0) << 4) | ((hdr)->TrafficClass1))
#define WINDIVERT_IPV6HDR_GET_FLOWLABEL(hdr)                \
    ((((UINT32)(hdr)->FlowLabel0) << 16) | ((UINT32)(hdr)->FlowLabel1))

#define WINDIVERT_IPV6HDR_SET_TRAFFICCLASS(hdr, val)        \
    do                                                      \
    {                                                       \
        (hdr)->TrafficClass0 = ((UINT8)(val) >> 4);         \
        (hdr)->TrafficClass1 = (UINT8)(val);                \
    }                                                       \
    while (FALSE)
#define WINDIVERT_IPV6HDR_SET_FLOWLABEL(hdr, val)           \
    do                                                      \
    {                                                       \
        (hdr)->FlowLabel0 = (UINT8)((val) >> 16);           \
        (hdr)->FlowLabel1 = (UINT16)(val);                  \
    }                                                       \
    while (FALSE)

    typedef struct
    {
        UINT8  Type;
        UINT8  Code;
        UINT16 Checksum;
        UINT32 Body;
    } WINDIVERT_ICMPHDR, * PWINDIVERT_ICMPHDR;

    typedef struct
    {
        UINT8  Type;
        UINT8  Code;
        UINT16 Checksum;
        UINT32 Body;
    } WINDIVERT_ICMPV6HDR, * PWINDIVERT_ICMPV6HDR;

    typedef struct
    {
        UINT16 SrcPort;
        UINT16 DstPort;
        UINT32 SeqNum;
        UINT32 AckNum;
        UINT16 Reserved1 : 4;
        UINT16 HdrLength : 4;
        UINT16 Fin : 1;
        UINT16 Syn : 1;
        UINT16 Rst : 1;
        UINT16 Psh : 1;
        UINT16 Ack : 1;
        UINT16 Urg : 1;
        UINT16 Reserved2 : 2;
        UINT16 Window;
        UINT16 Checksum;
        UINT16 UrgPtr;
    } WINDIVERT_TCPHDR, * PWINDIVERT_TCPHDR;

    typedef struct
    {
        UINT16 SrcPort;
        UINT16 DstPort;
        UINT16 Length;
        UINT16 Checksum;
    } WINDIVERT_UDPHDR, * PWINDIVERT_UDPHDR;

#ifndef WINDIVERT_KERNEL

    /*
     * Flags for WinDivertHelperCalcChecksums()
     */
#define WINDIVERT_HELPER_NO_IP_CHECKSUM                     1
#define WINDIVERT_HELPER_NO_ICMP_CHECKSUM                   2
#define WINDIVERT_HELPER_NO_ICMPV6_CHECKSUM                 4
#define WINDIVERT_HELPER_NO_TCP_CHECKSUM                    8
#define WINDIVERT_HELPER_NO_UDP_CHECKSUM                    16

     /*
      * Parse IPv4/IPv6/ICMP/ICMPv6/TCP/UDP headers from a raw packet.
      */
    extern WINDIVERTEXPORT BOOL WinDivertHelperParsePacket(
        __in        PVOID pPacket,
        __in        UINT packetLen,
        __out_opt   PWINDIVERT_IPHDR* ppIpHdr,
        __out_opt   PWINDIVERT_IPV6HDR* ppIpv6Hdr,
        __out_opt   PWINDIVERT_ICMPHDR* ppIcmpHdr,
        __out_opt   PWINDIVERT_ICMPV6HDR* ppIcmpv6Hdr,
        __out_opt   PWINDIVERT_TCPHDR* ppTcpHdr,
        __out_opt   PWINDIVERT_UDPHDR* ppUdpHdr,
        __out_opt   PVOID* ppData,
        __out_opt   UINT* pDataLen);

    /*
     * Parse an IPv4 address.
     */
    extern WINDIVERTEXPORT BOOL WinDivertHelperParseIPv4Address(
        __in        const char* addrStr,
        __out_opt   UINT32* pAddr);

    /*
     * Parse an IPv6 address.
     */
    extern WINDIVERTEXPORT BOOL WinDivertHelperParseIPv6Address(
        __in        const char* addrStr,
        __out_opt   UINT32* pAddr);

    /*
     * Calculate IPv4/IPv6/ICMP/ICMPv6/TCP/UDP checksums.
     */
    extern WINDIVERTEXPORT UINT WinDivertHelperCalcChecksums(
        __inout     PVOID pPacket,
        __in        UINT packetLen,
        __in_opt    PWINDIVERT_ADDRESS pAddr,
        __in        UINT64 flags);

    /*
     * Check the given filter string.
     */
    extern WINDIVERTEXPORT BOOL WinDivertHelperCheckFilter(
        __in        const char* filter,
        __in        WINDIVERT_LAYER layer,
        __out_opt   const char** errorStr,
        __out_opt   UINT* errorPos);

    /*
     * Evaluate the given filter string.
     */
    extern WINDIVERTEXPORT BOOL WinDivertHelperEvalFilter(
        __in        const char* filter,
        __in        WINDIVERT_LAYER layer,
        __in        PVOID pPacket,
        __in        UINT packetLen,
        __in        PWINDIVERT_ADDRESS pAddr);

#endif      /* WINDIVERT_KERNEL */

#ifdef __cplusplus
}
#endif

#endif      /* __WINDIVERT_H */