mirror of
https://github.com/yv1ing/rdp_channel.git
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140 lines
3.0 KiB
Go
140 lines
3.0 KiB
Go
package protocol
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"io"
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)
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/* 协议常量 */
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// X224消息头部长度
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const (
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X224_HEADER_LENGTH = 0x07
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)
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// X224消息类型字段标识
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const (
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X224_CONNECTION_REQUEST byte = 0xE0
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X224_CONNECTION_CONFIRM byte = 0xD0
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X224_DISCONNECT_REQUEST byte = 0x80
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X224_DATA byte = 0xF0
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X224_ERROR byte = 0x70
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)
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// X224 协议封装
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type X224 struct {
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transport *TPKT
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reqProtocol uint32
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selProtocol uint32
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}
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type X224PDU struct {
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Len uint8
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Type byte
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DstRef uint16 // 大端序
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SrcRef uint16 // 大端序
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ClsOpt uint8
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Payload []byte
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}
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func NewX224(conn io.ReadWriter) *X224 {
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return &X224{
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transport: NewTPKT(conn),
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}
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}
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// 从字节流中解析PDU头部
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func (x *X224) parsePDUHeader(reader *bytes.Reader, pdu *X224PDU) error {
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var err error
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// 读取Len字段
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err = binary.Read(reader, binary.BigEndian, &pdu.Len)
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if err != nil {
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return errors.New("[X224] failed to read pdu length: " + err.Error())
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}
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// 读取Type字段
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err = binary.Read(reader, binary.BigEndian, &pdu.Type)
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if err != nil {
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return errors.New("[X224] failed to read pdu type: " + err.Error())
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}
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// 读取DstRef（大端序）
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err = binary.Read(reader, binary.BigEndian, &pdu.DstRef)
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if err != nil {
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return errors.New("[X224] failed to read pdu dstref: " + err.Error())
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}
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// 读取SrcRef（大端序）
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err = binary.Read(reader, binary.BigEndian, &pdu.SrcRef)
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if err != nil {
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return errors.New("[X224] failed to read pdu srcref: " + err.Error())
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}
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// 读取ClsOpt
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err = binary.Read(reader, binary.BigEndian, &pdu.ClsOpt)
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if err != nil {
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return errors.New("[X224] failed to read pdu clsopt: " + err.Error())
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}
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return nil
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}
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// 序列化X224PDU
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func (x *X224) serializeX224PDU(pdu *X224PDU) []byte {
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buff := bytes.NewBuffer(nil)
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_ = binary.Write(buff, binary.BigEndian, pdu.Len)
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_ = binary.Write(buff, binary.BigEndian, pdu.Type)
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_ = binary.Write(buff, binary.BigEndian, pdu.DstRef)
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_ = binary.Write(buff, binary.BigEndian, pdu.SrcRef)
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_ = binary.Write(buff, binary.BigEndian, pdu.ClsOpt)
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buff.Write(pdu.Payload)
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return buff.Bytes()
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}
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// 封包
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func (x *X224) Write(payload []byte) error {
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pdu := &X224PDU{
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Len: uint8(X224_HEADER_LENGTH + len(payload)), // 头部长度 + 载荷字段
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Type: X224_DATA,
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DstRef: 0xf0,
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SrcRef: 0xf1,
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ClsOpt: 0x0,
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Payload: payload,
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}
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payloadBytes := x.serializeX224PDU(pdu)
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err := x.transport.Write(payloadBytes)
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if err != nil {
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return errors.New("[X224] failed to write: " + err.Error())
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}
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return nil
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}
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// 解包
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func (x *X224) Read() ([]byte, error) {
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packet, err := x.transport.Read()
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if err != nil {
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return nil, errors.New("[X224] failed to read: " + err.Error())
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}
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pdu := &X224PDU{}
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reader := bytes.NewReader(packet)
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err = x.parsePDUHeader(reader, pdu)
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if err != nil {
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return nil, errors.New("[X224] failed to parse pdu header: " + err.Error())
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}
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payload, err := io.ReadAll(reader)
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if err != nil {
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return nil, errors.New("[X224] failed to read payload: " + err.Error())
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}
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return payload, nil
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}
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