Golang简单实现端口扫描器(TCP)

效果如下:

思路:

直接net.Dial，这里我所以的是net.DialTimeout可以设置超时，否则默认好像是20S，然后就是结合sync.waitgroup及goroutine即可实现批量扫描端口

Code:

package main

import (
	"flag"
	"fmt"
	"net"
	"strconv"
	"strings"
	"sync"
	"time"
)
var wg sync.WaitGroup

func scan(ip string,port int) {
	addr:=ip+":"+strconv.Itoa(port)
	conn,_:=net.DialTimeout("tcp",addr,5*time.Second)
	if conn != nil {
		conn.Close()
		fmt.Println(addr+"=====>Opened")
		wg.Done()
	}else {
		fmt.Println(addr+"=====>Closeed")
		wg.Done()
	}
}

func main()  {
	before:=time.Now()
	var ip string
	var port int
	var ports string
	flag.StringVar(&ip,"ip","127.0.0.1","input ip")
	flag.IntVar(&port,"port",80,"input port")
	flag.StringVar(&ports,"ports","","input ports")
	flag.Parse()
	if ports=="" {
		scan(ip,port)
	}else{
		ps:=strings.Split(ports,"-")
		top,_:=strconv.Atoi(ps[0])
		bot,_:=strconv.Atoi(ps[1])
		for i:=top;i<=bot;i++{
			wg.Add(1)
			go scan(ip,i)
		}
	}
	wg.Wait()
	after:=time.Now()
	fmt.Printf("扫描完毕!耗时:%v\n",after.Sub(before))
}