first pass

cmd/main.go

@@ -0,0 +1,928 @@
+package main
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"os"
+)
+
+func main() {
+
+	go listenBOS()
+
+	// Listen on TCP port 5190
+	listener, err := net.Listen("tcp", ":5190")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer listener.Close()
+
+	fmt.Println("Server is listening on port 5190")
+
+	for {
+		// Accept incoming connections
+		conn, err := listener.Accept()
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+
+		// Handle connection in a separate goroutine
+		go handleAuthConnection(conn)
+	}
+}
+
+func listenBOS() {
+	// Listen on TCP port 5190
+	listener, err := net.Listen("tcp", ":5191")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer listener.Close()
+
+	fmt.Println("Server is listening on port 5191")
+
+	for {
+		// Accept incoming connections
+		conn, err := listener.Accept()
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+
+		go handleBOSConnection(conn)
+	}
+}
+
+func handleAuthConnection(conn net.Conn) {
+	defer conn.Close()
+
+	if err := writeFlapSignonFrame(conn); err != nil {
+		log.Println(err)
+		return
+	}
+
+	_, err := ReadFlapSignonFrame(conn)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	sequenceNumber, err := ReadAuthChallengeRequest(conn)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	err = WriteAuthChallengeResponse(conn, sequenceNumber+1)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	_, err = ReadBUCPLoginRequest(conn)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	err = WriteBUCPLoginResponse(conn, sequenceNumber+1)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+}
+
+func handleBOSConnection(conn net.Conn) {
+	//defer conn.Close()
+
+	if err := writeFlapSignonFrame(conn); err != nil {
+		log.Println(err)
+		return
+	}
+
+	bufLen, err := ReadFlapSignonFrame(conn)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	fmt.Println("Reading BOS login request...")
+
+	buf := make([]byte, bufLen)
+
+	_, err = conn.Read(buf)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	if err := printTLV(bytes.NewBuffer(buf)); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	if err := WriteOServiceHostOnline(conn, 0); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+}
+
+func writeFlapSignonFrame(conn net.Conn) error {
+
+	startMarker := uint8(42)
+	if err := binary.Write(conn, binary.BigEndian, startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	frameType := uint8(1)
+	if err := binary.Write(conn, binary.BigEndian, frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	sequenceNumber := uint16(100)
+	if err := binary.Write(conn, binary.BigEndian, sequenceNumber); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	payloadLength := uint16(4)
+	if err := binary.Write(conn, binary.BigEndian, payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	flapVersion := uint32(1)
+	if err := binary.Write(conn, binary.BigEndian, flapVersion); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	return nil
+}
+
+func ReadFlapSignonFrame(conn net.Conn) (uint16, error) {
+
+	var startMarker uint8
+	if err := binary.Read(conn, binary.BigEndian, &startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Printf("start marker: %d\n", startMarker)
+
+	var frameType uint8
+	if err := binary.Read(conn, binary.BigEndian, &frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Printf("frame type: %d\n", frameType)
+
+	var sequenceNumber uint16
+	if err := binary.Read(conn, binary.BigEndian, &sequenceNumber); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("sequence number: %d\n", sequenceNumber)
+
+	var payloadLength uint16
+	if err := binary.Read(conn, binary.BigEndian, &payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("payload length: %d\n", payloadLength)
+
+	var flapVersion uint32
+	if err := binary.Read(conn, binary.BigEndian, &flapVersion); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("flap version: %d\n", flapVersion)
+
+	return payloadLength, nil
+}
+
+func ReadAuthChallengeRequest(conn net.Conn) (uint16, error) {
+
+	fmt.Println("Reading snac...")
+
+	var startMarker uint8
+	if err := binary.Read(conn, binary.BigEndian, &startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Printf("start marker: %d\n", startMarker)
+
+	var frameType uint8
+	if err := binary.Read(conn, binary.BigEndian, &frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Printf("frame type: %d\n", frameType)
+
+	var sequenceNumber uint16
+	if err := binary.Read(conn, binary.BigEndian, &sequenceNumber); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("sequence number: %d\n", sequenceNumber)
+
+	var payloadLength uint16
+	if err := binary.Read(conn, binary.BigEndian, &payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("payload length: %d\n", payloadLength)
+
+	remainder := make([]byte, payloadLength)
+	if _, err := conn.Read(remainder); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	snacBuf := bytes.NewBuffer(remainder)
+
+	fmt.Println("Reading Snac header...")
+
+	var foodGroup uint16
+	if err := binary.Read(snacBuf, binary.BigEndian, &foodGroup); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("food group: %d\n", foodGroup)
+	// 23 = 0x17 = https://wiki.nina.chat/wiki/Protocols/OSCAR#Foodgroups BUCP (0x0017)
+	var foodGroupType uint16
+	if err := binary.Read(snacBuf, binary.BigEndian, &foodGroupType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("foodGroupType: %d\n", foodGroupType)
+	// 6 = 0x0006 = BUCP__CHALLENGE_REQUEST
+	var flags uint16
+	if err := binary.Read(snacBuf, binary.BigEndian, &flags); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("flags: %d\n", flags)
+
+	var requestID uint32
+	if err := binary.Read(snacBuf, binary.BigEndian, &requestID); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("requestID: %d\n", requestID)
+
+	var tag uint16
+	if err := binary.Read(snacBuf, binary.BigEndian, &tag); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("tag: %d\n", tag)
+
+	var screenNameLen uint16
+	if err := binary.Read(snacBuf, binary.BigEndian, &screenNameLen); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("screenNameLen: %d\n", screenNameLen)
+
+	screenNameBuf := make([]byte, screenNameLen)
+	if _, err := snacBuf.Read(screenNameBuf); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("screen name: %s\n", screenNameBuf)
+
+	return sequenceNumber, nil
+}
+
+func WriteAuthChallengeResponse(conn net.Conn, sequenceNumber uint16) error {
+	fmt.Println("Writing auth challenge response...")
+
+	startMarker := uint8(42)
+	if err := binary.Write(conn, binary.BigEndian, startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	frameType := uint8(2)
+	if err := binary.Write(conn, binary.BigEndian, frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	seq := uint16(101)
+	if err := binary.Write(conn, binary.BigEndian, seq); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	b := make([]byte, 0)
+	snacBuf := bytes.NewBuffer(b)
+
+	{
+		foodGroup := uint16(0x17)
+		if err := binary.Write(snacBuf, binary.BigEndian, foodGroup); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		foodGroupType := uint16(7)
+		if err := binary.Write(snacBuf, binary.BigEndian, foodGroupType); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		flags := uint16(0x00)
+		if err := binary.Write(snacBuf, binary.BigEndian, flags); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		requestID := uint32(0x00)
+		if err := binary.Write(snacBuf, binary.BigEndian, requestID); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		authKey := []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5}
+		authKeyLen := uint32(len(authKey))
+		if err := binary.Write(snacBuf, binary.BigEndian, authKeyLen); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		if _, err := snacBuf.Write(authKey); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+	}
+
+	payloadLength := uint16(snacBuf.Len())
+	if err := binary.Write(conn, binary.BigEndian, payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	if _, err := conn.Write(snacBuf.Bytes()); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	return nil
+}
+
+func ReadBUCPLoginRequest(conn net.Conn) (uint16, error) {
+
+	fmt.Println("Reading BUCP login request...")
+
+	var startMarker uint8
+	if err := binary.Read(conn, binary.BigEndian, &startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Printf("start marker: %d\n", startMarker)
+
+	var frameType uint8
+	if err := binary.Read(conn, binary.BigEndian, &frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Printf("frame type: %d\n", frameType)
+
+	var sequenceNumber uint16
+	if err := binary.Read(conn, binary.BigEndian, &sequenceNumber); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("sequence number: %d\n", sequenceNumber)
+
+	var payloadLength uint16
+	if err := binary.Read(conn, binary.BigEndian, &payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("payload length: %d\n", payloadLength)
+
+	fmt.Println("Reading Snac header...")
+
+	var foodGroup uint16
+	if err := binary.Read(conn, binary.BigEndian, &foodGroup); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("food group: %d\n", foodGroup)
+	// 23 = 0x17 = https://wiki.nina.chat/wiki/Protocols/OSCAR#Foodgroups BUCP (0x0017)
+	var foodGroupType uint16
+	if err := binary.Read(conn, binary.BigEndian, &foodGroupType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("foodGroupType: %d\n", foodGroupType)
+	// 6 = 0x0006 = BUCP__CHALLENGE_REQUEST
+	var flags uint16
+	if err := binary.Read(conn, binary.BigEndian, &flags); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("flags: %d\n", flags)
+
+	var requestID uint32
+	if err := binary.Read(conn, binary.BigEndian, &requestID); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	fmt.Printf("requestID: %d\n", requestID)
+
+	err := printBUCPTLV(conn)
+	if err != nil && err != io.EOF {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+	fmt.Println("HEREW!")
+	return sequenceNumber, nil
+}
+
+func WriteBUCPLoginResponse(conn net.Conn, sequenceNumber uint16) error {
+	fmt.Println("Writing bucp login response...")
+
+	startMarker := uint8(42)
+	if err := binary.Write(conn, binary.BigEndian, startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	frameType := uint8(2)
+	if err := binary.Write(conn, binary.BigEndian, frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	seq := uint16(102)
+	if err := binary.Write(conn, binary.BigEndian, seq); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	b := make([]byte, 0)
+	snacBuf := bytes.NewBuffer(b)
+
+	{
+		foodGroup := uint16(0x17)
+		if err := binary.Write(snacBuf, binary.BigEndian, foodGroup); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		foodGroupType := uint16(0x03)
+		if err := binary.Write(snacBuf, binary.BigEndian, foodGroupType); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		flags := uint16(0x00)
+		if err := binary.Write(snacBuf, binary.BigEndian, flags); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		requestID := uint32(0x00)
+		if err := binary.Write(snacBuf, binary.BigEndian, requestID); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		if err := writeTLV(snacBuf, 0x01, "myscreenname"); err != nil {
+			return err
+		}
+
+		if err := writeTLV(snacBuf, 0x08, uint16(0x00)); err != nil {
+			return err
+		}
+
+		if err := writeTLV(snacBuf, 0x04, ""); err != nil {
+			return err
+		}
+
+		if err := writeTLV(snacBuf, 0x05, "192.168.64.1:5191"); err != nil {
+			return err
+		}
+
+		if err := writeTLV(snacBuf, 0x06, []byte("thecookie")); err != nil {
+			return err
+		}
+
+		if err := writeTLV(snacBuf, 0x11, "mike@localhost"); err != nil {
+			return err
+		}
+
+		if err := writeTLV(snacBuf, 0x54, "http://localhost"); err != nil {
+			return err
+		}
+	}
+
+	payloadLength := uint16(snacBuf.Len())
+	if err := binary.Write(conn, binary.BigEndian, payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	if _, err := conn.Write(snacBuf.Bytes()); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	return nil
+}
+
+func writeTLV(w io.Writer, tlvID uint16, val any) error {
+	if err := binary.Write(w, binary.BigEndian, tlvID); err != nil {
+		return err
+	}
+	switch val := val.(type) {
+	case uint16:
+		tlvValLen := uint16(2)
+		if err := binary.Write(w, binary.BigEndian, tlvValLen); err != nil {
+			return err
+		}
+		if err := binary.Write(w, binary.BigEndian, val); err != nil {
+			return err
+		}
+	case uint32:
+		tlvValLen := uint16(4)
+		if err := binary.Write(w, binary.BigEndian, tlvValLen); err != nil {
+			return err
+		}
+		if err := binary.Write(w, binary.BigEndian, val); err != nil {
+			return err
+		}
+	case string:
+		tlvValLen := uint16(len(val))
+		if err := binary.Write(w, binary.BigEndian, tlvValLen); err != nil {
+			return err
+		}
+		_, err := w.Write([]byte(val))
+		if err != nil {
+			return err
+		}
+	case []byte:
+		tlvValLen := uint16(len(val))
+		if err := binary.Write(w, binary.BigEndian, tlvValLen); err != nil {
+			return err
+		}
+		_, err := w.Write(val)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func printBUCPTLV(r io.Reader) error {
+
+	for {
+		var tlvID uint16
+		if err := binary.Read(r, binary.BigEndian, &tlvID); err != nil {
+			return err
+		}
+
+		var tlvValLen uint16
+		if err := binary.Read(r, binary.BigEndian, &tlvValLen); err != nil {
+			return err
+		}
+
+		fmt.Printf("(%d) ", tlvID)
+		switch tlvID {
+		case 0x01: // screen name
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("screen name: %s", val)
+		case 0x03: // client id string
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client id string: %s", val)
+		case 0x25: // password md5 hash
+			val, err := readBytes(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("password md5 hash: %b\n", val)
+		case 0x16: // client id
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client id (len=%d): %d", tlvValLen, val)
+		case 0x17: // client major version
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client major version (len=%d): %d", tlvValLen, val)
+		case 0x18: // client minor version
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client minor version (len=%d): %d", tlvValLen, val)
+		case 0x19: // client lesser version
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client lesser version (len=%d): %d", tlvValLen, val)
+		case 0x1A: // client build number
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client build number (len=%d): %d", tlvValLen, val)
+		case 0x14: // distribution number
+			val, err := readUint32(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("distribution number (len=%d): %d", tlvValLen, val)
+		case 0x0F: // client language (2 symbols)
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client language (2 symbols) (len=%d): %s", tlvValLen, val)
+		case 0x0E: // client country (2 symbols)
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client country (2 symbols) (len=%d): %s", tlvValLen, val)
+		case 0x4A: // SSI use flag
+			val, err := readBytes(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			// buddy list thing?
+			fmt.Printf("SSI use flag (len=%d): %d", tlvValLen, val[0])
+			return nil
+		case 0x004c:
+			fmt.Printf("Use old MD5?\n")
+		case 0x06:
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("login cookie (len=%d): %s", tlvValLen, val)
+		default:
+			fmt.Printf("unknown TLV: %d (len=%d)", tlvID, tlvValLen)
+			_, err := r.Read(make([]byte, tlvValLen))
+			if err != nil {
+				return err
+			}
+		}
+
+		fmt.Println()
+	}
+}
+
+func printTLV(r io.Reader) error {
+
+	for {
+		var tlvID uint16
+		if err := binary.Read(r, binary.BigEndian, &tlvID); err != nil {
+			return err
+		}
+
+		var tlvValLen uint16
+		if err := binary.Read(r, binary.BigEndian, &tlvValLen); err != nil {
+			return err
+		}
+
+		fmt.Printf("(%d) ", tlvID)
+		switch tlvID {
+		case 0x01: // screen name
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("screen name: %s", val)
+		case 0x03: // client id string
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client id string: %s", val)
+		case 0x25: // password md5 hash
+			val, err := readBytes(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("password md5 hash: %b\n", val)
+		case 0x16: // client id
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client id (len=%d): %d", tlvValLen, val)
+		case 0x17: // client major version
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client major version (len=%d): %d", tlvValLen, val)
+		case 0x18: // client minor version
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client minor version (len=%d): %d", tlvValLen, val)
+		case 0x19: // client lesser version
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client lesser version (len=%d): %d", tlvValLen, val)
+		case 0x1A: // client build number
+			val, err := readUint16(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client build number (len=%d): %d", tlvValLen, val)
+		case 0x14: // distribution number
+			val, err := readUint32(r)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("distribution number (len=%d): %d", tlvValLen, val)
+		case 0x0F: // client language (2 symbols)
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client language (2 symbols) (len=%d): %s", tlvValLen, val)
+		case 0x0E: // client country (2 symbols)
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("client country (2 symbols) (len=%d): %s", tlvValLen, val)
+		case 0x4A: // SSI use flag
+			val, err := readBytes(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			// buddy list thing?
+			fmt.Printf("SSI use flag (len=%d): %d", tlvValLen, val[0])
+			return nil
+		case 0x004c:
+			fmt.Printf("Use old MD5?\n")
+		case 0x06:
+			val, err := readString(r, tlvValLen)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("login cookie (len=%d): %s\n", tlvValLen, val)
+			for {
+				buf := make([]byte, 1)
+				_, err := r.Read(buf)
+				if err != nil {
+					return nil
+				}
+				fmt.Println(buf)
+			}
+		default:
+			fmt.Printf("unknown TLV: %d (len=%d)", tlvID, tlvValLen)
+			_, err := r.Read(make([]byte, tlvValLen))
+			if err != nil {
+				return err
+			}
+		}
+
+		fmt.Println()
+	}
+}
+
+func WriteOServiceHostOnline(conn net.Conn, sequenceNumber uint16) error {
+	fmt.Println("Writing service host online...")
+
+	startMarker := uint8(42)
+	if err := binary.Write(conn, binary.BigEndian, startMarker); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	frameType := uint8(2)
+	if err := binary.Write(conn, binary.BigEndian, frameType); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	seq := uint16(101)
+	if err := binary.Write(conn, binary.BigEndian, seq); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	b := make([]byte, 0)
+	snacBuf := bytes.NewBuffer(b)
+
+	{
+		foodGroup := uint16(0x01)
+		if err := binary.Write(snacBuf, binary.BigEndian, foodGroup); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		foodGroupType := uint16(0x03)
+		if err := binary.Write(snacBuf, binary.BigEndian, foodGroupType); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		flags := uint16(0x00)
+		if err := binary.Write(snacBuf, binary.BigEndian, flags); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		requestID := uint32(0x00)
+		if err := binary.Write(snacBuf, binary.BigEndian, requestID); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		authKey := []uint16{0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F, 0x0010, 0x0013, 0x0015, 0x0017, 0x0018, 0x0022, 0x0024, 0x0025, 0x044A}
+		if err := binary.Write(snacBuf, binary.BigEndian, &authKey); err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+	}
+
+	payloadLength := uint16(snacBuf.Len())
+	if err := binary.Write(conn, binary.BigEndian, payloadLength); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	if _, err := conn.Write(snacBuf.Bytes()); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	return nil
+}
+
+func readString(r io.Reader, len uint16) (string, error) {
+	buf := make([]byte, len)
+	if _, err := r.Read(buf); err != nil {
+		return "", err
+	}
+	return string(buf), nil
+}
+
+func readBytes(r io.Reader, len uint16) ([]byte, error) {
+	buf := make([]byte, len)
+	if _, err := r.Read(buf); err != nil {
+		return buf, err
+	}
+	return buf, nil
+}
+
+func readUint16(r io.Reader) (uint16, error) {
+	var val uint16
+	binary.Read(r, binary.BigEndian, &val)
+	return val, nil
+}
+
+func readUint32(r io.Reader) (uint32, error) {
+	var val uint32
+	binary.Read(r, binary.BigEndian, &val)
+	return val, nil
+}

go.mod

@@ -0,0 +1,3 @@
+module goaim
+
+go 1.20