Know who is viewing your miCam

miCam.go

package main

import (
	"bufio"
	"crypto/tls"
	"fmt"
	log "github.com/sirupsen/logrus"
	"golang.org/x/time/rate"
	"net/http"
	"os/exec"
	"regexp"
	"runtime"
	"strings"
	"time"
)

const (
	bucketSize = 70
	bucketRate = 35
)

var limiter = rate.NewLimiter(bucketRate, bucketSize)

func runner() {

	http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{InsecureSkipVerify: true}

	var c string
	//c = "ping localhost"
	c = "/usr/bin/tcpdump -i br-lan udp and host 192.168.7.35"
	args := strings.Fields(c)
	cmd := exec.Command(args[0], args[1:]...)

	stderr, _ := cmd.StdoutPipe()
	err := cmd.Start()
	if err != nil {
		log.Fatalln("Running tcpdump error", err)
	}

	scanner := bufio.NewScanner(stderr)
	// 21:10:08.443881 IP 110.43.47.109.23647 > chuangmi_camera_029a02.lan.22732: UDP, length 24
	// 16:49:18.905980 IP chuangmi.lan.13701 > 120.92.158.164.32100: UDP, length 48
	re1 := regexp.MustCompile(`IP chuangmi.*\.lan\.\d+ > \d+\.\d+\.\d+\.\d+\.\d+: UDP`)
	re2 := regexp.MustCompile(`IP \d+\.\d+\.\d+\.\d+\.\d+ > chuangmi.*\.lan\.\d+: UDP`)
	//re2 := regexp.MustCompile(`icmp`)

	for scanner.Scan() {
		m := scanner.Text()
		result1 := re1.FindString(m)
		result2 := re2.FindString(m)
		if len(result1) != 0 || len(result2) != 0 {
			if limiter.Allow() {
				log.Infof("Potential request: %s", m)
			} else {
				log.Warnln("Potential request, sending now...")
				sendAlert(m)
			}
		}
	}
}

func sendAlert(viewInfo string) {
	var cstZone = time.FixedZone("GMT", 8*3600)
	var nowTime = time.Now().In(cstZone).Format("2006-01-02 15:04:05")
	message := fmt.Sprintf("%s == %s\n", nowTime, viewInfo)
	log.Infoln(message)
}

func setupLogger() {
	log.SetReportCaller(true)
	Formatter := &log.TextFormatter{
		EnvironmentOverrideColors: true,
		FullTimestamp:             true,
		TimestampFormat:           "2006-01-02 15:04:05",
		CallerPrettyfier: func(f *runtime.Frame) (string, string) {
			return fmt.Sprintf("[%s()]", f.Function), ""
		},
	}
	log.SetFormatter(Formatter)
}

func main() {
	setupLogger()
	fmt.Println("Watcher is running.")
	runner()
}