在Go中设置idletimeout

huangapple
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英文:

Setting idletimeout in Go

问题

我在Go语言中有一个处理通过TCP传入并通过SSH处理的连接的函数。我正在尝试通过在连接函数中创建结构体来设置空闲超时时间。

用例 - 客户应该能够建立连接并上传/下载多个文件

参考 - https://stackoverflow.com/questions/47912263/idletimeout-in-tcp-server

函数代码：

  1. type Conn struct {
  2.     net.Conn
  3.     idleTimeout time.Duration
  4. }
  6. func HandleConn(conn net.Conn) {
  7.     var err error
  8.     rAddr := conn.RemoteAddr()
  9.     session := shortuuid.New()
  10.     config := LoadSSHServerConfig(session)
  12.     blocklistItem := blocklist.GetBlockListItem(rAddr)
  13.     if blocklistItem.IsBlocked() {
  14.         conn.Close()
  15.         atomic.AddInt64(&stats.Stats.BlockedConnections, 1)
  16.         return
  17.     }
  19.     func (c *Conn) Read(b []byte) (int, error) {
  20.         err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout))
  21.         if err != nil {
  22.             return 0, err
  23.         }
  24.         return c.Conn.Read(b)
  25.     }
  27.     sConn, chans, reqs, err := ssh.NewServerConn(conn, config)
  28.     if err != nil {
  29.         if err == io.EOF {
  30.             log.Errorw("SSH: Handshaking was terminated", log.Fields{
  31.                 "address": rAddr,
  32.                 "error":   err,
  33.                 "session": session})
  34.         } else {
  35.             log.Errorw("SSH: Error on handshaking", log.Fields{
  36.                 "address": rAddr,
  37.                 "error":   err,
  38.                 "session": session})
  39.         }
  41.         atomic.AddInt64(&stats.Stats.AuthorizationFailed, 1)
  42.         return
  43.     }
  45.     log.Infow("connection accepted", log.Fields{
  46.         "user": sConn.User(),
  47.     })
  49.     if user, ok := users[session]; ok {
  50.         log.Infow("SSH: Connection accepted", log.Fields{
  51.             "user":          user.LogFields(),
  52.             "clientVersion": string(sConn.ClientVersion())})
  54.         atomic.AddInt64(&stats.Stats.AuthorizationSucceeded, 1)
  56.         // The incoming Request channel must be serviced.
  57.         go ssh.DiscardRequests(reqs)
  59.         // Key ID: sConn.Permissions.Extensions["key-id"]
  60.         handleServerConn(user, chans)
  62.         log.Infow("connection finished", log.Fields{"user": user.LogFields()})
  64.         log.Infow("checking connections", log.Fields{
  65.             // "cc":          Stats.AcceptedConnections,
  66.             "cc2": &stats.Stats.AcceptedConnections})
  68.         // Remove connection from local cache
  69.         delete(users, session)
  71.     } else {
  72.         log.Infow("user not found from memory", log.Fields{"username": sConn.User()})
  73.     }
  75. }

这段代码来自Listen函数：

  1. func Listen() {
  4.     listener, err := net.Listen("tcp", sshListen)
  5.     if err != nil {
  6.         panic(err)
  7.     }
  10.     if useProxyProtocol {
  11.         listener = &proxyproto.Listener{
  12.             Listener:           listener,
  13.             ProxyHeaderTimeout: time.Second * 10,
  14.         }
  15.     }
  18.     for {
  19.         // Once a ServerConfig has been configured, connections can be accepted.
  20.         conn, err := listener.Accept()
  21.         if err != nil {
  22.             log.Errorw("SSH: Error accepting incoming connection", log.Fields{"error": err})
  23.             atomic.AddInt64(&stats.Stats.FailedConnections, 1)
  24.             continue
  25.         }
  28.         // Before use, a handshake must be performed on the incoming net.Conn.
  29.         // It must be handled in a separate goroutine,
  30.         // otherwise one user could easily block entire loop.
  31.         // For example, user could be asked to trust server key fingerprint and hangs.
  32.         go HandleConn(conn)
  33.     }
  34. }

是否可能仅为空闲超过20秒（无上传/下载）的连接设置截止时间？

编辑1：根据@LiamKelly的建议，我已经对代码进行了更改。现在代码如下：

  1. type SshProxyConn struct {
  2.     net.Conn
  3.     idleTimeout time.Duration
  4. }
  6. func (c *SshProxyConn) Read(b []byte) (int, error) {
  7.     err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout))
  8.     if err != nil {
  9.         return 0, err
  10.     }
  11.     return c.Conn.Read(b)
  12. }
  13. func HandleConn(conn net.Conn) {
  14.     //与上述代码相同的行
  15.     sshproxyconn := &SshProxyConn{nil, time.Second * 20}
  16.     Conn, chans, reqs, err := ssh.NewServerConn(sshproxyconn, config)
  17.     //与上述代码相同的行
  18. }
  20. 但现在的问题是SSH无法进行。当我尝试进行SSH时，我收到错误消息"Connection closed"。它是否仍在等待函数调用中的"conn"变量？
  22. <details>
  23. <summary>英文:</summary>
  25. I have a function in go which is handling connections which are coming through tcp and handled via ssh. I am trying to set an idle timeout by creating struct in the connection function. 
  27. **Use case** - a customer should be able to make a connection and upload/download multiple files
  29. **Reference** - https://stackoverflow.com/questions/47912263/idletimeout-in-tcp-server
  31. Function code:
  36.     type Conn struct {
  37.         		net.Conn
  38.         		idleTimeout time.Duration
  39.         	}
  41.     func HandleConn(conn net.Conn) {
  42.     	var err error
  43.     	rAddr := conn.RemoteAddr()
  44.     	session := shortuuid.New()
  45.     	config := LoadSSHServerConfig(session)
  46.        
  47.     	blocklistItem := blocklist.GetBlockListItem(rAddr)
  48.     	if blocklistItem.IsBlocked() {
  49.     		conn.Close()
  50.     		atomic.AddInt64(&amp;stats.Stats.BlockedConnections, 1)
  51.     		return
  52.     	}
  53.     
  54.     	
  55.     	func (c *Conn) Read(b []byte) (int, error) {
  56.     		err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout))
  57.     		if err != nil {
  58.     			return 0, err
  59.     		}
  60.     		return c.Conn.Read(b)
  61.     	}
  62.     
  63.     	sConn, chans, reqs, err := ssh.NewServerConn(conn, config)
  64.     	if err != nil {
  65.     		if err == io.EOF {
  66.     			log.Errorw(&quot;SSH: Handshaking was terminated&quot;, log.Fields{
  67.     				&quot;address&quot;: rAddr,
  68.     				&quot;error&quot;:   err,
  69.     				&quot;session&quot;: session})
  70.     		} else {
  71.     			log.Errorw(&quot;SSH: Error on handshaking&quot;, log.Fields{
  72.     				&quot;address&quot;: rAddr,
  73.     				&quot;error&quot;:   err,
  74.     				&quot;session&quot;: session})
  75.     		}
  76.     
  77.     		atomic.AddInt64(&amp;stats.Stats.AuthorizationFailed, 1)
  78.     		return
  79.     	}
  80.     
  81.     	log.Infow(&quot;connection accepted&quot;, log.Fields{
  82.     		&quot;user&quot;: sConn.User(),
  83.     	})
  84.     
  85.     	if user, ok := users[session]; ok {
  86.     		log.Infow(&quot;SSH: Connection accepted&quot;, log.Fields{
  87.     			&quot;user&quot;:          user.LogFields(),
  88.     			&quot;clientVersion&quot;: string(sConn.ClientVersion())})
  89.     
  90.     		atomic.AddInt64(&amp;stats.Stats.AuthorizationSucceeded, 1)
  91.             
  92.     		// The incoming Request channel must be serviced.
  93.     		go ssh.DiscardRequests(reqs)
  94.     
  95.     		// Key ID: sConn.Permissions.Extensions[&quot;key-id&quot;]
  96.     		handleServerConn(user, chans)
  97.     
  98.     		log.Infow(&quot;connection finished&quot;, log.Fields{&quot;user&quot;: user.LogFields()})
  99.             
  100.     		log.Infow(&quot;checking connections&quot;, log.Fields{
  101.     			//&quot;cc&quot;:          Stats.AcceptedConnections,
  102.     			&quot;cc2&quot;: &amp;stats.Stats.AcceptedConnections})
  103.     
  104.     		// Remove connection from local cache
  105.     		delete(users, session)
  106.     
  107.     	} else {
  108.     		log.Infow(&quot;user not found from memory&quot;, log.Fields{&quot;username&quot;: sConn.User()})
  109.     	}
  110.     
  111.     }
  114. This code is coming from the Listen function:
  116.     func Listen() {
  117.        
  118.     
  119.     	listener, err := net.Listen(&quot;tcp&quot;, sshListen)
  120.     	if err != nil {
  121.     		panic(err)
  122.     	}
  123.         
  124.     
  125.     	if useProxyProtocol {
  126.     		listener = &amp;proxyproto.Listener{
  127.     			Listener:           listener,
  128.     			ProxyHeaderTimeout: time.Second * 10,
  129.     		}
  130.     	}
  131.     
  132.     	
  133.     	for {
  134.     		// Once a ServerConfig has been configured, connections can be accepted.
  135.     		conn, err := listener.Accept()
  136.     		if err != nil {
  137.     			log.Errorw(&quot;SSH: Error accepting incoming connection&quot;, log.Fields{&quot;error&quot;: err})
  138.     			atomic.AddInt64(&amp;stats.Stats.FailedConnections, 1)
  139.     			continue
  140.     		}
  141.     	
  142.     
  143.     		// Before use, a handshake must be performed on the incoming net.Conn.
  144.     		// It must be handled in a separate goroutine,
  145.     		// otherwise one user could easily block entire loop.
  146.     		// For example, user could be asked to trust server key fingerprint and hangs.
  147.     		go HandleConn(conn)
  148.     	}
  149.     }
  152. Is that even possible to set a deadline for only the connections which have been idle for 20 secinds (no upload/downloads).
  154. **EDIT 1** : Following @LiamKelly&#39;s suggestions, I have made the changes in the code. Now the code is like 
  156.     type SshProxyConn struct {
  157.         net.Conn
  158.         idleTimeout time.Duration
  159.     }
  160.     
  161.     func (c *SshProxyConn) Read(b []byte) (int, error) {
  162.         err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout))
  163.         if err != nil {
  164.             return 0, err
  165.         }
  166.         return c.Conn.Read(b)
  167.     }
  168.     func HandleConn(conn net.Conn) {
  169.         //lines of code as above
  170.         sshproxyconn := &amp;SshProxyConn{nil, time.Second * 20}
  171.         Conn, chans, reqs, err := ssh.NewServerConn(sshproxyconn, config)
  172.         //lines of code
  173.     }
  175. But now the issue is that SSH is not happening. I am getting the error &quot;Connection closed&quot; when I try to do ssh. Is it still waiting for &quot;conn&quot; variable in the function call?
  178. </details>
  181. # 答案1
  182. **得分**: 1
  184. &gt; 是否可能仅为空闲超过20秒的连接设置截止日期？
  186. 首先，我要声明一下，我会假设`go-protoproxy`实现了我们期望的`Conn`接口。另外，正如你之前暗示的，我认为你不能将一个结构体方法放在另一个函数内（我还建议将其重命名为一个独特的名称，以避免`Conn`与`net.Conn`混淆）。
  188. ```go
  189. type SshProxyConn struct {
  190. 	net.Conn
  191. 	idleTimeout time.Duration
  192. }
  194. func (c *SshProxyConn) Read(b []byte) (int, error) {
  195. 	err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout))
  196. 	if err != nil {
  197. 		return 0, err
  198. 	}
  199. 	return c.Conn.Read(b)
  200. }
  202. func HandleConn(conn net.Conn) {

这样更清楚地显示了你的主要问题，你将普通的net.Conn传递给了SSH服务器，而不是你的包装类。所以

  1. sConn, chans, reqs, err := ssh.NewServerConn(conn, config)

应该更改为 编辑

  1. sshproxyconn := &SshProxyConn{conn, time.Second * 20}
  2. Conn, chans, reqs, err := ssh.NewServerConn(sshproxyconn, config)
英文:

> Is that even possible to set a deadline for only the connections which have been idle for 20 [seconds]

Ok so first a general disclaimer, I am going to assume go-protoproxy implements the Conn interface as we would expected. Also as you hinted at before, I don't think you can put a a struct method inside another function (I also recommend renaming it something unique to prevent Conn vs net.Conn confusion).

  1. type SshProxyConn struct {
  2. 	net.Conn
  3. 	idleTimeout time.Duration
  4. }
  6. func (c *SshProxyConn) Read(b []byte) (int, error) {
  7. 	err := c.Conn.SetReadDeadline(time.Now().Add(c.idleTimeout))
  8. 	if err != nil {
  9. 		return 0, err
  10. 	}
  11. 	return c.Conn.Read(b)
  12. }
  15. func HandleConn(conn net.Conn) {

This makes is more clear what your primary issue is, which you passed the normal net.Conn to your SSH server, not your wrapper class. So

  1. sConn, chans, reqs, err := ssh.NewServerConn(conn, config)

should be EDIT

  1. sshproxyconn := &amp;SshProxyConn{conn, time.Second * 20}
  2. Conn, chans, reqs, err := ssh.NewServerConn(sshproxyconn , config)

huangapple
  • 本文由 发表于 2022年9月22日 19:56:40
  • 转载请务必保留本文链接：https://go.coder-hub.com/73814237.html
  • connection
  • go
  • idle-timer
  • session-timeout
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