utils.go

package main

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"strings"
)

// IntToHex converts an int64 to a byte array
func IntToHex(num int64) []byte {
	buff := new(bytes.Buffer)
	err := binary.Write(buff, binary.BigEndian, num)
	if err != nil {
		log.Panic(err)
	}

	return buff.Bytes()
}

// ReverseBytes reverses a byte array
func ReverseBytes(data []byte) {
	for i, j := 0, len(data)-1; i < j; i, j = i+1, j-1 {
		data[i], data[j] = data[j], data[i]
	}
}

func GetExternalIp() string {
	resp, err := http.Get("http://myexternalip.com/raw")
	if err != nil {
		return ""
	}
	defer resp.Body.Close()
	content, _ := ioutil.ReadAll(resp.Body)
	return string(content)
}

func GetInternalIp() string {
	conn, err := net.Dial("udp", "google.com:80")
	if err != nil {
		fmt.Println(err.Error())
		log.Panic(err)
	}
	defer conn.Close()
	return strings.Split(conn.LocalAddr().String(), ":")[0]
}