Go语言实现的简单网络端口扫描代码

Go语言实现的简单网络端口扫描代码

package main
import (
	"net"
	"fmt"
	"os"
	"runtime"
	"time"
	"strconv"
)
func loop(startport, endport int, inport chan int) {
		for i := startport; i <= endport; i++{
			inport <- i
		}
}
func scanner(inport, outport, out chan int, ip net.IP, endport int){
	for{
		in := <- inport
		//fmt.Println(in)
		tcpaddr := &net.TCPAddr{ip,in}
		conn, err := net.DialTCP("tcp", nil, tcpaddr)
		if err != nil {
			outport <- 0
		}else{
			outport <- in 
		}
		conn.Close()
		if in == endport{
			out <- in
		}
	}
}
func main() {
	starttime := time.Now().Unix()
	runtime.GOMAXPROCS(4)
	inport := make(chan int)
	outport := make(chan int)
	out := make(chan int)
	collect := []int{}
	if len(os.Args) != 4 {
		fmt.Println("Usage: scanner.exe IP startport endport")
		fmt.Println("Endport must be larger than startport")
		os.Exit(0)
	}
	ip := net.ParseIP(os.Args[1])
	if(os.Args[3] < os.Args[2]) {
		fmt.Println("Usage: scanner IP startport endport")
		fmt.Println("Endport must be larger than startport")
		os.Exit(0)
	}
	startport, _:= strconv.Atoi(os.Args[2])
	endport, _ := strconv.Atoi(os.Args[3])
	go loop(startport, endport, inport)
	for{
		select {
			case <-out:
				fmt.Println(collect)
				endtime := time.Now().Unix()
				fmt.Println("The scan process has spent ",endtime-starttime,"second")
				os.Exit(0)
			default:
				go scanner(inport, outport, out, ip, endport)
				
				port := <- outport
				
				if port != 0{
					collect = append(collect, port)
				}
		}		
	}
}