完成TPKT、X224、FastPath协议基本封装和测试

protocol/tpkt.go

@@ -0,0 +1,91 @@
+package protocol
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+)
+
+/*
+	定义协议相关的常量值
+*/
+
+const (
+	TPKT_VERSION           = 0x03
+	TPKT_RESERVED          = 0x00
+	TPKT_HEADER_LENGTH     = 0x04
+	TPKT_MAX_PACKET_LENGTH = 0xffff
+)
+
+/*
+	TPKT结构体封装
+*/
+
+type TPKT struct {
+	conn io.ReadWriter
+}
+
+func NewTPKT(conn io.ReadWriter) *TPKT {
+	return &TPKT{
+		conn: conn,
+	}
+}
+
+/*
+	TPKT封包
+*/
+
+func (t *TPKT) Write(payload []byte) error {
+	pduLength := TPKT_HEADER_LENGTH + len(payload)
+	if pduLength > TPKT_MAX_PACKET_LENGTH {
+		return errors.New("[TPKT] packet length too long")
+	}
+
+	// 构造TPKT头（4 bytes）：
+	pdu := make([]byte, pduLength)
+	pdu[0] = TPKT_VERSION
+	pdu[1] = TPKT_RESERVED
+	binary.BigEndian.PutUint16(pdu[2:4], uint16(pduLength))
+
+	// 装入TPKT载荷
+	copy(pdu[4:], payload)
+
+	_, err := t.conn.Write(pdu)
+	if err != nil {
+		return errors.New("[TPKT] write error: " + err.Error())
+	}
+
+	return nil
+}
+
+/*
+	TPKT解包
+*/
+
+func (t *TPKT) Read() ([]byte, error) {
+	// 验证TPKT头
+	pduHeader := make([]byte, TPKT_HEADER_LENGTH)
+	_, err := io.ReadFull(t.conn, pduHeader)
+	if err != nil {
+		return nil, errors.New("[TPKT] read pdu header error: " + err.Error())
+	}
+
+	if pduHeader[0] != TPKT_VERSION {
+		return nil, errors.New("[TPKT] version mismatch")
+	}
+
+	pduLength := binary.BigEndian.Uint16(pduHeader[2:4])
+	if pduLength > TPKT_MAX_PACKET_LENGTH {
+		return nil, errors.New("[TPKT] packet length too long")
+	}
+
+	// 读取TPKT载荷
+	payloadLength := pduLength - TPKT_HEADER_LENGTH
+	payload := make([]byte, payloadLength)
+	_, err = io.ReadFull(t.conn, payload)
+	if err != nil {
+		return nil, errors.New("[TPKT] read pdu payload error: " + err.Error())
+	}
+
+	return payload, nil
+}