douge3830
2019-05-28 06:27
浏览 785
已采纳

Golang检查TCP端口打开

I need to check if remote address has specific TCP ports open or not. I have chosen to use golang for this purpose. Here is my attempt so far:

func raw_connect(host string, ports []string) {
  for _, port := range ports {
     timeout := time.Second
     conn, err := net.DialTimeout("tcp", host + ":" + port, timeout)
     if err != nil {
        _, err_msg := err.Error()[0], err.Error()[5:]
        fmt.Println(err_msg)
     } else {
        msg, _, err := bufio.NewReader(conn).ReadLine()
        if err != nil {
           if err == io.EOF {
              fmt.Print(host + " " + port + " - Open!
")
           }
        } else {
           fmt.Print(host + " " + port + " - " + string(msg))
        }
        conn.Close()
     }
   }
 }

This is working just fine for TCP port when application (such as SSH) returns first a string, I read it and print it with no time.

However, when the application above TCP is waiting for command from the client first (such as HTTP), there is a timeout (if err == io.EOF clause).

This timeout is quite long. I would need to know immediately if the port is open or not.

Is there a more suitable technique for this purpose ?

Many thanks!

图片转代码服务由CSDN问答提供 功能建议

我需要检查远程地址是否打开了特定的TCP端口。 我已选择为此目的使用golang。 到目前为止,这是我的尝试:

  func raw_connect(host string,ports [] string){
表示_,  port:=范围端口{
超时:= time.Second 
 conn,err:= net.DialTimeout(“ tcp”,host +“:” + port,timeout)
 if err!= nil {
 _  ,err_msg:= err.Error()[0],err.Error()[5:] 
 fmt.Println(err_msg)
}其他{
 msg,_,err:= bufio.NewReader(conn)  .ReadLine()
 if err!= nil {
 if err == io.EOF {
 fmt.Print(host +“” + port +“-Open!
”)
} 
} else  {
 fmt.Print(host +“” +端口+“-” +字符串(msg))
} 
 conn.Close()
} 
} 
} 
    pre> 
 
 

当应用程序(例如SSH)首先返回一个字符串时,这对于TCP端口来说就很好,我立即读取并打印了它。

但是,当TCP之上的应用程序首先等待来自客户端的命令(例如HTTP)时,会出现超时( if err == io.EOF 子句)。

此超时时间很长。 我需要立即知道端口是否打开。

是否有更合适的技术用于此目的?

非常感谢! / p>

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1条回答 默认 最新

  • duan19805 2019-05-28 07:11
    已采纳

    To check the port, you can check if the connection was successful. For example:

    func raw_connect(host string, ports []string) {
        for _, port := range ports {
            timeout := time.Second
            conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, port), timeout)
            if err != nil {
                fmt.Println("Connecting error:", err)
            }
            if conn != nil {
                defer conn.Close()
                fmt.Println("Opened", net.JoinHostPort(host, port))
            }
        }
    }
    
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