ping.go

package main

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"time"
)

var (
	UknCode_1   byte
	UknCode_2   byte
	UknCode_3   byte
	globalCheck [4]byte
)

var counter byte

/* 信息包校验码计算 */
func putCode1(buf []byte) {
	v5 := len(buf) >> 2
	var v6 uint32
	var tmp uint32
	var b_tmp *bytes.Buffer
	binary.LittleEndian.PutUint32(buf[24:28], 20000711)
	binary.LittleEndian.PutUint32(buf[28:32], 126)
	for i := 0; i < v5; i++ {
		b_tmp = bytes.NewBuffer(buf[4*i : 4*i+4])
		binary.Read(b_tmp, binary.LittleEndian, &tmp)
		v6 ^= tmp
	}
	binary.LittleEndian.PutUint32(buf[24:28], v6*19680126)
	buf[28] = 0
	fmt.Println(v6 * 19680126)
	binary.LittleEndian.PutUint32(globalCheck[:], v6*19680126)
}

/* 40字节心跳包校验码计算 */
func putCode2(buf []byte) {
	var tmp, v5 uint16
	var b_tmp *bytes.Buffer
	for i := 0; i < 20; i++ {
		b_tmp = bytes.NewBuffer(buf[2*i : 2*i+2])
		binary.Read(b_tmp, binary.LittleEndian, &tmp)
		v5 ^= tmp
	}
	binary.LittleEndian.PutUint32(buf[24:28], uint32(v5)*711)
}

func sendPingStart() {
	udpConn.Write([]byte{0x07, 0x00, 0x08, 0x00, 0x01, 0x00, 0x00, 0x00})
}

/* 两种心跳包循环发送 */
func pingCycle() {
	time.Sleep(1 * time.Second)
	for {
		sendPing40(1)
		time.Sleep(10 * time.Second)
		sendPing38()
		time.Sleep(5 * time.Second)
	}
}

/* 40字节心跳包发送 */
func sendPing40(step byte) {
	var buf [40]byte
	buf[0] = 0x07
	buf[1] = counter
	buf[2] = 0x28
	buf[4] = 0x0b
	buf[5] = step
	copy(buf[6:10], []byte{0xdc, 0x02, 0x6c, 0x6f})
	if step == 3 {
		copy(buf[28:32], clientip[:])
		putCode2(buf[:])
	}
	counter = counter + 1
	udpConn.Write(buf[:])
}

/* 38字节心跳包发送 */
func sendPing38() {
	var buf [38]byte
	buf[0] = 0xff
	copy(buf[1:5], globalCheck[:])
	copy(buf[5:17], challenge[4:16])
	copy(buf[20:24], "Drco")
	copy(buf[24:28], serverip[:])
	buf[28] = UknCode_1
	if UknCode_2 >= 128 {
		buf[29] = UknCode_2<<1 | 1
	} else {
		buf[29] = UknCode_2 << 1
	}
	copy(buf[30:34], clientip[:])
	buf[34] = 0x01
	if UknCode_3%2 == 0 {
		buf[35] = UknCode_3 >> 1
	} else {
		buf[35] = UknCode_3>>1 | 128
	}
	binary.LittleEndian.PutUint16(buf[36:38], uint16(time.Now().Unix()))
	udpConn.Write(buf[:])
}

/* 信息包发送 */
func sendPingInfo(data []byte) {
	var buf [244]byte
	var otherInfo [201]byte
	usrLength := len(username)

	buf[0] = 0x07
	buf[1] = 0x01
	buf[2] = byte(usrLength + 233)
	buf[4] = 0x03
	buf[5] = byte(usrLength)
	copy(buf[6:12], mac)
	copy(buf[12:16], clientip[:])
	copy(buf[16:20], []byte{0x02, 0x22, 0x00, 0x24})
	copy(buf[20:24], data)
	copy(buf[32:], username)
	hostname := "sgu"
	copy(otherInfo[0:32], hostname)
	copy(otherInfo[32:36], []byte{223, 5, 5, 5})
	copy(otherInfo[40:44], []byte{223, 6, 6, 6})
	otherInfo[52] = 0x94
	otherInfo[56] = 0x06
	otherInfo[60] = 0x02
	otherInfo[64] = 0xf0
	otherInfo[65] = 0x23
	otherInfo[68] = 0x02
	copy(otherInfo[72:77], "DrCOM")
	copy(otherInfo[77:82], []byte{0x05, 0xb8, 0x01, 0x04})
	copy(otherInfo[136:176], "391515fd339f62b530cd63a027cd4ef95139069f")
	copy(buf[32+usrLength:233+usrLength], otherInfo[:])

	putCode1(buf[:usrLength+233])
	udpConn.Write(buf[:usrLength+233])
}

/* 接收服务器的UDP回应 */
func recvPing() {
	data := [4096]byte{}
	for {
		n, _, err := udpConn.ReadFromUDP(data[0:])
		if err != nil {
			fmt.Println(err)
		}
		if n > 0 {
			if data[0] == 0x07 { //应答包
				if data[2] == 0x10 && n == 32 { //第一次应答
					sendPingInfo(data[8:12]) //发送用户信息包
				} else if data[2] == 0x30 { //第二次应答
					UknCode_1 = data[24]
					UknCode_2 = data[25]
					UknCode_3 = data[31]
					go pingCycle() //发送Ping-1
				} else if data[2] == 0x28 { //Ping应答
					if data[5] == 0x02 { //收到Ping-2
						sendPing40(3) //发送Ping-3
					}
				}
			}
		}
	}
}