Adding a timeout to the connection

.gitignore

@@ -0,0 +1 @@
+go.mod

main.go

@@ -1,36 +1,49 @@
 package main
 
 import (
+	"time"
+	"flag"
 	"fmt"
 	"net"
 	"sync"
 )
+//IsOpen connect to ports
+func IsOpen(ipstr string,port int,timeout time.Duration) bool{
+	target:= fmt.Sprintf("%s:%d",ipstr,port)
+	conn, err := net.DialTimeout("tcp", target, timeout)
+
+	if err != nil {
+		return false
+	}
+	defer conn.Close()
+	return true
+}
 
 func main() {
 
-	hostname := "localhost"
+	// input user -ip "1.1.1.1"
+	var ipstr string
+    flag.StringVar(&ipstr, "ip", "localhost", "ip target")
+	flag.Parse()
 
 	// worker pool channel
-	conSema := make(chan struct{}, 10)
 
+	timeout:=500*time.Millisecond
 	var wg sync.WaitGroup
+	conSema:= make(chan bool,10)
+
 	for i := 1; i < 65535; i++ {
 		wg.Add(1)
-		conSema <- struct{}{}
+		conSema <- true
 		go func(port int) {
-			addr := fmt.Sprintf("%s:%d", hostname, port)
-			conn, err := net.Dial("tcp", addr)
-			if err != nil {
-				// handle error
-				fmt.Printf("port %d closed: %v\n", port, err)
-			} else {
-				fmt.Printf("port %d open\n", port)
-				conn.Close()
+
+			if IsOpen(ipstr,port,timeout){
+				fmt.Printf("Open port: %d \n",port)
 			}
+
 			<-conSema
 			wg.Done()
 		}(i)
 	}
 	wg.Wait()
-
 }