mirror of
https://github.com/yv1ing/rdp_channel.git
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69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
package fastpath
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import (
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"encoding/binary"
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"errors"
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"rdp_channel/protocol/core/transport"
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)
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// 协议常量
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const (
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FASTPATH_PDU_HEADER_LENGTH = 0x4 // updateHeader(1 bytes) + compressionFlags(1 bytes) + size(2 bytes)
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FASTPATH__MAX_PACKET_LENGTH = 0xffff
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FASTPATH_UPDATETYPE_ORDERS uint32 = 0x0
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FASTPATH_UPDATETYPE_BITMAP uint32 = 0x1
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)
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const (
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// update header: https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/a1c4caa8-00ed-45bb-a06e-5177473766d3
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FASTPATH_UPDATE_HEADER uint8 = 0x8
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FASTPATH_COMPRESSION_FLAGS uint8 = 0x0
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)
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var (
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FASTPATH_INVALID_PACKET_LENGTH = errors.New("[FASTPATH] invalid packet length")
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)
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type FastPath struct {
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transport transport.Transport
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}
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func New(transport transport.Transport) *FastPath {
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return &FastPath{
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transport: transport,
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}
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}
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func (fp *FastPath) Write(data []byte) (int, error) {
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/*
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构造PDU
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格式参考：https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/0ae3c114-1439-4465-8d3f-6585227eff7d
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*/
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dataLen := len(data)
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if dataLen > FASTPATH__MAX_PACKET_LENGTH {
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return dataLen, FASTPATH_INVALID_PACKET_LENGTH
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}
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size := uint16(FASTPATH_PDU_HEADER_LENGTH + dataLen)
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pdu := make([]byte, size)
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pdu[0] = FASTPATH_UPDATE_HEADER
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pdu[1] = FASTPATH_COMPRESSION_FLAGS
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binary.LittleEndian.PutUint16(pdu[2:4], size)
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copy(pdu[4:], data)
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return fp.transport.Write(pdu)
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}
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func (fp *FastPath) Read() (int, []byte, error) {
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_, packet, err := fp.transport.Read()
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if err != nil {
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return 0, nil, err
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}
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data := packet[FASTPATH_PDU_HEADER_LENGTH:]
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return len(data), data, nil
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}
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