mirror of
https://github.com/yv1ing/rdp_channel.git
synced 2025-09-16 14:59:08 +08:00
92 lines
1.7 KiB
Go
92 lines
1.7 KiB
Go
package protocol
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import (
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"encoding/binary"
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"errors"
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"io"
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)
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/*
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定义协议相关的常量值
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*/
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const (
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TPKT_VERSION = 0x03
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TPKT_RESERVED = 0x00
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TPKT_HEADER_LENGTH = 0x04
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TPKT_MAX_PACKET_LENGTH = 0xffff
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)
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/*
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TPKT结构体封装
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*/
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type TPKT struct {
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conn io.ReadWriter
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}
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func NewTPKT(conn io.ReadWriter) *TPKT {
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return &TPKT{
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conn: conn,
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}
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}
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/*
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TPKT封包
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*/
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func (t *TPKT) Write(payload []byte) error {
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pduLength := TPKT_HEADER_LENGTH + len(payload)
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if pduLength > TPKT_MAX_PACKET_LENGTH {
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return errors.New("[TPKT] packet length too long")
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}
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// 构造TPKT头（4 bytes）：
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pdu := make([]byte, pduLength)
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pdu[0] = TPKT_VERSION
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pdu[1] = TPKT_RESERVED
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binary.BigEndian.PutUint16(pdu[2:4], uint16(pduLength))
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// 装入TPKT载荷
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copy(pdu[4:], payload)
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_, err := t.conn.Write(pdu)
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if err != nil {
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return errors.New("[TPKT] write error: " + err.Error())
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}
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return nil
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}
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/*
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TPKT解包
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*/
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func (t *TPKT) Read() ([]byte, error) {
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// 验证TPKT头
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pduHeader := make([]byte, TPKT_HEADER_LENGTH)
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_, err := io.ReadFull(t.conn, pduHeader)
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if err != nil {
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return nil, errors.New("[TPKT] read pdu header error: " + err.Error())
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}
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if pduHeader[0] != TPKT_VERSION {
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return nil, errors.New("[TPKT] version mismatch")
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}
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pduLength := binary.BigEndian.Uint16(pduHeader[2:4])
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if pduLength > TPKT_MAX_PACKET_LENGTH {
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return nil, errors.New("[TPKT] packet length too long")
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}
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// 读取TPKT载荷
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payloadLength := pduLength - TPKT_HEADER_LENGTH
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payload := make([]byte, payloadLength)
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_, err = io.ReadFull(t.conn, payload)
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if err != nil {
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return nil, errors.New("[TPKT] read pdu payload error: " + err.Error())
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}
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return payload, nil
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}
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