basic_tcp_port_scanner.go

package main

import (
	"fmt"
	"net"
	"time"
)

type TargetHost struct {
	ip string
}

func checkPortOpen(ip string, port int, timeout time.Duration) bool {
	conn, _ := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", ip, port), timeout)

	if conn == nil {
		return false
	}

	conn.Close()

	return true
}

func (t *TargetHost) FindOpenPorts(start, stop int) (ports []int) {
	seconds := 1
	timeout := (time.Duration(seconds) * time.Second)
	for port := start; port <= stop; port++ {
		if checkPortOpen(t.ip, port, timeout) {
			ports = append(ports, port)
		}
	}
	return
}

func main() {
	t := TargetHost{"127.0.0.1"}
	p := t.FindOpenPorts(1, 1024)
	fmt.Println(p)
}