基本完成TPKT协议

go.mod

@@ -0,0 +1,3 @@
+module rdp_channel
+
+go 1.24

protocol/tpkt/tpkt.go

@@ -0,0 +1,86 @@
+package tpkt
+
+import (
+	"bufio"
+	"encoding/binary"
+	"errors"
+	"io"
+	"net"
+)
+
+// 协议常量
+const (
+	TPKT_VERSION           = 0x03
+	TPKT_RESERVED          = 0x00
+	TPKT_HEADER_LENGTH     = 0x04
+	TPKT_MAX_PACKET_LENGTH = 0xffff
+)
+
+var (
+	TPKT_INVALID_VERSION       = errors.New("[TPKT] invalid version")
+	TPKT_INVALID_PACKET_LENGTH = errors.New("[TPKT] invalid packet length")
+)
+
+// TPKT 协议封装
+type TPKT struct {
+	connection net.Conn
+	readBuff   *bufio.Reader
+}
+
+func New(conn net.Conn) *TPKT {
+	tpkt := &TPKT{
+		connection: conn,
+		readBuff:   bufio.NewReader(conn),
+	}
+
+	return tpkt
+}
+
+// Write 发送TPKT包
+func (tpkt *TPKT) Write(data []byte) (int, error) {
+	dataLen := len(data)
+	if dataLen > (TPKT_MAX_PACKET_LENGTH - TPKT_HEADER_LENGTH) {
+		return 0, TPKT_INVALID_PACKET_LENGTH
+	}
+
+	// TPKT封包
+	packet := make([]byte, TPKT_HEADER_LENGTH+dataLen)
+	packet[0] = TPKT_VERSION
+	packet[1] = TPKT_RESERVED
+	binary.BigEndian.PutUint16(packet[2:4], uint16(TPKT_HEADER_LENGTH+dataLen)) // 第2、3字节为tpkt包的长度
+
+	// 装填载荷
+	copy(packet[TPKT_HEADER_LENGTH:], data)
+
+	// 发送TPKT包
+	return tpkt.connection.Write(packet)
+}
+
+func (tpkt *TPKT) Read() (int, []byte, error) {
+	// 验证TPKT头
+	header := make([]byte, TPKT_HEADER_LENGTH)
+	_, err := io.ReadFull(tpkt.readBuff, header)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	// 验证TPKT版本
+	if header[0] != TPKT_VERSION {
+		return 0, nil, TPKT_INVALID_VERSION
+	}
+
+	// 验证载荷长度
+	length := binary.BigEndian.Uint16(header[2:4])
+	if length > TPKT_MAX_PACKET_LENGTH {
+		return 0, nil, TPKT_INVALID_PACKET_LENGTH
+	}
+
+	// 读取载荷数据
+	dataLen := length - TPKT_HEADER_LENGTH
+	data := make([]byte, dataLen)
+	if _, err := io.ReadFull(tpkt.readBuff, data); err != nil {
+		return 0, nil, err
+	}
+
+	return int(dataLen), data, nil
+}

protocol/tpkt/tpkt_test.go

@@ -0,0 +1,68 @@
+package tpkt
+
+import (
+	"net"
+	"testing"
+)
+
+func TestTpkt(t *testing.T) {
+	go runServer(t)
+	runClient(t)
+}
+
+func runServer(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:3388")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+	t.Logf("tpkt server listening at %s\n", listener.Addr())
+
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			t.Logf("tpkt server accept error: %s\n", err)
+			continue
+		}
+
+		t.Logf("tpkt server accepted connection from %s\n", conn.RemoteAddr())
+		go func(conn net.Conn) {
+			defer conn.Close()
+
+			tpkt := New(conn)
+			dataLen, data, err := tpkt.Read()
+			if err != nil {
+				t.Logf("tpkt server read error: %s\n", err)
+				return
+			}
+
+			t.Logf("tpkt server read data(%d): %q\n", dataLen, data)
+
+			_, err = tpkt.Write([]byte("tpkt server hello"))
+			if err != nil {
+				t.Logf("tpkt server write error: %s\n", err)
+			}
+		}(conn)
+	}
+}
+
+func runClient(t *testing.T) {
+	conn, err := net.Dial("tcp", "127.0.0.1:3388")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+
+	tpkt := New(conn)
+
+	_, err = tpkt.Write([]byte("tpkt client hello"))
+	if err != nil {
+		t.Logf("tpkt client write error: %s\n", err)
+	}
+
+	dataLen, data, err := tpkt.Read()
+	if err != nil {
+		t.Logf("tpkt client read error: %s\n", err)
+	}
+	t.Logf("tpkt client read data(%d): %q\n", dataLen, data)
+}