kappanhang/main.go

package main

import (
	"bytes"
	"crypto/rand"
	"encoding/binary"
	"fmt"
	"net"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/nonoo/kappanhang/log"
)

var conn *net.UDPConn
var localSID uint32
var remoteSID uint32
var sendSeq uint16
var authSendSeq uint16
var authInnerSendSeq uint16
var authID [6]byte
var randIDByteForPktSeven [1]byte
var expectedPkt7ReplySeq uint16
var lastReauthAt time.Time

func send(d []byte) {
	_, err := conn.Write(d)
	if err != nil {
		log.Fatal(err)
	}
}

func read() ([]byte, error) {
	err := conn.SetReadDeadline(time.Now().Add(time.Second))
	if err != nil {
		log.Fatal(err)
	}

	b := make([]byte, 1500)
	n, _, err := conn.ReadFromUDP(b)
	if err != nil {
		if err, ok := err.(net.Error); ok && !err.Timeout() {
			log.Fatal(err)
		}
	}
	return b[:n], err
}

func setupCloseHandler() {
	c := make(chan os.Signal)
	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
	go func() {
		<-c
		log.Print("disconnecting")
		sendDisconnect()
		os.Exit(0)
	}()
}

func sendPkt7(replyID []byte, seq uint16) {
	// Example request from PC:  0x15, 0x00, 0x00, 0x00, 0x07, 0x00, 0x09, 0x00, 0xbe, 0xd9, 0xf2, 0x63, 0xe4, 0x35, 0xdd, 0x72, 0x00, 0x78, 0x40, 0xf6, 0x02
	// Example reply from radio: 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x09, 0x00, 0xe4, 0x35, 0xdd, 0x72, 0xbe, 0xd9, 0xf2, 0x63, 0x01, 0x78, 0x40, 0xf6, 0x02
	var replyFlag byte
	if replyID == nil {
		replyID = make([]byte, 4)
		var randID [2]byte
		_, err := rand.Read(randID[:])
		if err != nil {
			log.Fatal(err)
		}
		replyID[0] = randID[0]
		replyID[1] = randID[1]
		replyID[2] = randIDByteForPktSeven[0]
		replyID[3] = 0x03
	} else {
		replyFlag = 0x01
	}

	expectedPkt7ReplySeq = sendSeq

	send([]byte{0x15, 0x00, 0x00, 0x00, 0x07, 0x00, byte(seq), byte(seq >> 8),
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID),
		replyFlag, replyID[0], replyID[1], replyID[2], replyID[3]})
}

func sendPkt3() {
	send([]byte{0x10, 0x00, 0x00, 0x00, 0x03, 0x00, byte(sendSeq), byte(sendSeq >> 8),
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID)})
}

func sendPkt6() {
	send([]byte{0x10, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0x00,
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID)})
}

func sendPktLogin() {
	// The reply to the login packet will contain a 6 bytes long auth ID with the first 2 bytes set to our randID.
	var randID [2]byte
	_, err := rand.Read(randID[:])
	if err != nil {
		log.Fatal(err)
	}
	send([]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00,
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID),
		0x00, 0x00, 0x00, 0x70, 0x01, 0x00, 0x00, byte(authInnerSendSeq),
		byte(authInnerSendSeq >> 8), 0x00, randID[0], randID[1], 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x2b, 0x3f, 0x55, 0x5c, 0x00, 0x00, 0x00, 0x00, // username: beer
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x2b, 0x3f, 0x55, 0x5c, 0x3f, 0x25, 0x77, 0x58, // pass: beerbeer
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x69, 0x63, 0x6f, 0x6d, 0x2d, 0x70, 0x63, 0x00, // icom-pc in plain text
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
	authSendSeq++
	authInnerSendSeq++
}

func sendPktReauth(firstReauthSend bool) {
	var magic byte

	if firstReauthSend {
		magic = 0x02
	} else {
		magic = 0x05
	}

	// Example request from PC:  0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0d, 0x00,
	//                           0xbb, 0x41, 0x3f, 0x2b, 0xe6, 0xb2, 0x7b, 0x7b,
	//                           0x00, 0x00, 0x00, 0x30, 0x01, 0x05, 0x00, 0x02,
	//                           0x00, 0x00, 0x5d, 0x37, 0x12, 0x82, 0x3b, 0xde,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	// Example reply from radio: 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0x00,
	//                           0xe6, 0xb2, 0x7b, 0x7b, 0xbb, 0x41, 0x3f, 0x2b,
	//                           0x00, 0x00, 0x00, 0x30, 0x02, 0x05, 0x00, 0x02,
	//                           0x00, 0x00, 0x5d, 0x37, 0x12, 0x82, 0x3b, 0xde,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	send([]byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00, byte(authSendSeq), byte(authSendSeq >> 8),
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID),
		0x00, 0x00, 0x00, 0x30, 0x01, magic, 0x00, byte(authInnerSendSeq),
		byte(authInnerSendSeq >> 8), 0x00, authID[0], authID[1], authID[2], authID[3], authID[4], authID[5],
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
	authSendSeq++
	authInnerSendSeq++
	lastReauthAt = time.Now()
}

func sendDisconnect() {
	send([]byte{0x40, 0x00, 0x00, 0x00, 0x00, 0x00, byte(sendSeq), byte(sendSeq >> 8),
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID),
		0x00, 0x00, 0x00, 0x30, 0x01, 0x01, 0x00, byte(authInnerSendSeq),
		byte(authInnerSendSeq >> 8), 0x00, authID[0], authID[1], authID[2], authID[3], authID[4], authID[5],
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
	send([]byte{0x10, 0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x00,
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID),
		byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID)})
}

func sendRequestSerialAndAudio() {
	log.Print("requesting serial and audio stream")
	send([]byte{0x90, 0x00, 0x00, 0x00, 0x00, 0x00, byte(authSendSeq), byte(authSendSeq >> 8),
		byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID), byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID),
		0x00, 0x00, 0x00, 0x80, 0x01, 0x03, 0x00, byte(authInnerSendSeq),
		byte(authInnerSendSeq >> 8), 0x00, authID[0], authID[1], authID[2], authID[3], authID[4], authID[5],
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
		0x80, 0x00, 0x00, 0x90, 0xc7, 0x0e, 0x86, 0x01, // The last 5 bytes from this row can be acquired from a reply starting with 0xa8 or 0x90
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x49, 0x43, 0x2d, 0x37, 0x30, 0x35, 0x00, 0x00, // IC-705 in plain text
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x2b, 0x3f, 0x55, 0x5c, 0x00, 0x00, 0x00, 0x00, // username: beer
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x01, 0x01, 0x04, 0x04, 0x00, 0x00, 0xbb, 0x80,
		0x00, 0x00, 0xbb, 0x80, 0x00, 0x00, 0xc3, 0x52,
		0x00, 0x00, 0xc3, 0x53, 0x00, 0x00, 0x00, 0x64,
		0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
	authSendSeq++
	authInnerSendSeq++
}

func main() {
	log.Init()
	parseArgs()
	setupCloseHandler()

	hostPort := fmt.Sprint(connectAddress, ":50001")
	log.Print("connecting to ", hostPort)
	raddr, err := net.ResolveUDPAddr("udp", hostPort)
	if err != nil {
		log.Fatal(err)
	}
	laddr := net.UDPAddr{
		Port: 50001,
	}
	conn, err = net.DialUDP("udp", &laddr, raddr)
	if err != nil {
		log.Fatal(err)
	}

	localSID = uint32(time.Now().Unix())
	log.Debugf("using session id %.8x", localSID)

	sendPkt3()
	sendSeq = 1
	sendPkt7(nil, sendSeq)
	sendSeq = 0
	sendPkt3()

	for {
		// Expecting a Pkt4 answer.
		// Example answer from radio: 0x10, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x8c, 0x7d, 0x45, 0x7a, 0x1d, 0xf6, 0xe9, 0x0b
		r, _ := read()
		if len(r) == 16 && bytes.Equal(r[:8], []byte{0x10, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00}) {
			remoteSID = binary.BigEndian.Uint32(r[8:12])
			break
		}
	}

	log.Debugf("got remote session id %.8x", remoteSID)

	authSendSeq = 1
	authInnerSendSeq = 0x50
	sendPkt6()

	for {
		// Expecting a Pkt6 answer.
		r, _ := read()
		if len(r) == 16 && bytes.Equal(r[:8], []byte{0x10, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0x00}) {
			remoteSID = binary.BigEndian.Uint32(r[8:12])
			break
		}
	}

	sendPktLogin()
	sendSeq = 5

	// Example success auth packet: 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00,
	//                              0xe6, 0xb2, 0x7b, 0x7b, 0xbb, 0x41, 0x3f, 0x2b,
	//                              0x00, 0x00, 0x00, 0x50, 0x02, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x5d, 0x37, 0x12, 0x82, 0x3b, 0xde,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x46, 0x54, 0x54, 0x48, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	//                              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	for {
		r, _ := read()
		if len(r) == 96 && bytes.Equal(r[:8], []byte{0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00}) {
			if bytes.Equal(r[48:52], []byte{0xff, 0xff, 0xff, 0xfe}) {
				log.Fatal("invalid user/password")
			}

			copy(authID[:], r[26:32])
			log.Print("auth ok")
			sendPktReauth(true)
			time.AfterFunc(time.Second*2, sendRequestSerialAndAudio)
			break
		}
	}

	var lastPingAt time.Time
	var lastStatusLog time.Time
	var errCount int

	_, err = rand.Read(randIDByteForPktSeven[:])
	if err != nil {
		log.Fatal(err)
	}

	for {
		r, err := read()
		if err != nil {
			errCount++
			if errCount > 5 {
				log.Fatal("timeout")
			}
			log.Error("stream break detected")
		}
		errCount = 0

		if len(r) == 21 && bytes.Equal(r[1:6], []byte{0x00, 0x00, 0x00, 0x07, 0x00}) {
			gotSeq := binary.LittleEndian.Uint16(r[6:8])
			if r[16] == 0x00 { // This is a pkt7 request from the radio.
				// Replying to the radio.
				// Example request from radio: 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x1c, 0x0e, 0xe4, 0x35, 0xdd, 0x72, 0xbe, 0xd9, 0xf2, 0x63, 0x00, 0x57, 0x2b, 0x12, 0x00
				// Example answer from PC:     0x15, 0x00, 0x00, 0x00, 0x07, 0x00, 0x1c, 0x0e, 0xbe, 0xd9, 0xf2, 0x63, 0xe4, 0x35, 0xdd, 0x72, 0x01, 0x57, 0x2b, 0x12, 0x00
				sendPkt7(r[17:21], gotSeq)
			} else {
				if expectedPkt7ReplySeq != gotSeq { // TODO
					var missingPkts int
					if gotSeq > expectedPkt7ReplySeq {
						missingPkts = int(gotSeq) - int(expectedPkt7ReplySeq)
					} else {
						missingPkts = int(gotSeq) + 65536 - int(expectedPkt7ReplySeq)
					}
					if missingPkts < 1000 {
						log.Error("lost ", missingPkts, " packets ", gotSeq, " ", expectedPkt7ReplySeq)
					}
				}
			}
		}
		if len(r) == 16 && bytes.Equal(r[:6], []byte{0x10, 0x00, 0x00, 0x00, 0x00, 0x00}) {
			// Replying to the radio.
			// Example request from radio: 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x13, 0x00, 0xe4, 0x35, 0xdd, 0x72, 0xbe, 0xd9, 0xf2, 0x63
			// Example answer from PC:     0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x13, 0x00, 0xbe, 0xd9, 0xf2, 0x63, 0xe4, 0x35, 0xdd, 0x72
			gotSeq := binary.LittleEndian.Uint16(r[6:8])
			send([]byte{0x10, 0x00, 0x00, 0x00, 0x00, 0x00, byte(gotSeq), byte(gotSeq >> 8), byte(localSID >> 24), byte(localSID >> 16), byte(localSID >> 8), byte(localSID), byte(remoteSID >> 24), byte(remoteSID >> 16), byte(remoteSID >> 8), byte(remoteSID)})
		}
		if len(r) == 80 && bytes.Equal(r[:6], []byte{0x50, 0x00, 0x00, 0x00, 0x00, 0x00}) && bytes.Equal(r[48:51], []byte{0xff, 0xff, 0xff}) {
			// Example answer from radio: 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00,
			//							  0x86, 0x1f, 0x2f, 0xcc, 0x03, 0x03, 0x89, 0x29,
			//							  0x00, 0x00, 0x00, 0x40, 0x02, 0x03, 0x00, 0x52,
			//							  0x00, 0x00, 0xf8, 0xad, 0x06, 0x8d, 0xda, 0x7b,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
			//							  0x80, 0x00, 0x00, 0x90, 0xc7, 0x0e, 0x86, 0x01,
			//							  0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			//							  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

			log.Error("reauth failed")
			sendDisconnect()
			os.Exit(1)
		}
		if len(r) == 144 && bytes.Equal(r[:6], []byte{0x90, 0x00, 0x00, 0x00, 0x00, 0x00}) && r[96] == 1 {
			// Example answer:
			// 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x00,
			// 0xc6, 0x5f, 0x6f, 0x0c, 0x5f, 0x8b, 0x1e, 0x89,
			// 0x00, 0x00, 0x00, 0x80, 0x03, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x31, 0x30, 0x31, 0x47, 0x39, 0x07,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
			// 0x80, 0x00, 0x00, 0x90, 0xc7, 0x0e, 0x86, 0x01,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x49, 0x43, 0x2d, 0x37, 0x30, 0x35, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x01, 0x00, 0x00, 0x00, 0x69, 0x63, 0x6f, 0x6d,
			// 0x2d, 0x70, 0x63, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			// 0x00, 0x00, 0x00, 0x00, 0xc0, 0xa8, 0x03, 0x03,
			// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
			log.Print("serial and audio request success")
			go openAudioStream()
		}

		if time.Since(lastPingAt) >= 100*time.Millisecond {
			sendPkt7(nil, sendSeq)
			sendPkt3()
			sendSeq++
			lastPingAt = time.Now()

			if time.Since(lastReauthAt) >= 60*time.Second {
				sendPktReauth(false)
			}

			if time.Since(lastStatusLog) >= 10*time.Second {
				log.Print("still connected")
				lastStatusLog = time.Now()
			}
		}
	}
}