fix: Fix disconnect handler not working in production

backend/sshbackend/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -18,6 +19,32 @@ import (
 	"golang.org/x/crypto/ssh"
 )
 
+type ConnWithTimeout struct {
+	net.Conn
+	ReadTimeout  time.Duration
+	WriteTimeout time.Duration
+}
+
+func (c *ConnWithTimeout) Read(b []byte) (int, error) {
+	err := c.Conn.SetReadDeadline(time.Now().Add(c.ReadTimeout))
+
+	if err != nil {
+		return 0, err
+	}
+
+	return c.Conn.Read(b)
+}
+
+func (c *ConnWithTimeout) Write(b []byte) (int, error) {
+	err := c.Conn.SetWriteDeadline(time.Now().Add(c.WriteTimeout))
+
+	if err != nil {
+		return 0, err
+	}
+
+	return c.Conn.Write(b)
+}
+
 type SSHListener struct {
 	SourceIP   string
 	SourcePort uint16
@@ -76,16 +103,34 @@ func (backend *SSHBackend) StartBackend(bytes []byte) (bool, error) {
 		},
 	}
 
-	conn, err := ssh.Dial("tcp", fmt.Sprintf("%s:%d", backendData.IP, backendData.Port), config)
+	addr := fmt.Sprintf("%s:%d", backendData.IP, backendData.Port)
+	timeout := time.Duration(10 * time.Second)
+
+	rawTCPConn, err := net.DialTimeout("tcp", addr, timeout)
 
 	if err != nil {
 		return false, err
 	}
 
-	backend.conn = conn
+	connWithTimeout := &ConnWithTimeout{
+		Conn:         rawTCPConn,
+		ReadTimeout:  timeout,
+		WriteTimeout: timeout,
+	}
+
+	c, chans, reqs, err := ssh.NewClientConn(connWithTimeout, addr, config)
+
+	if err != nil {
+		return false, err
+	}
+
+	client := ssh.NewClient(c, chans, reqs)
+	backend.conn = client
+
+	go backend.backendDisconnectHandler()
+	go backend.backendKeepaliveHandler()
 
 	log.Info("SSHBackend has initialized successfully.")
-	go backend.backendDisconnectHandler()
 
 	return true, nil
 }
@@ -203,8 +248,7 @@ func (backend *SSHBackend) StartProxy(command *commonbackend.AddProxy) (bool, er
 							// Splice out the clientInstance by clientIndex
 
 							// TODO: change approach. It works but it's a bit wonky imho
-							// I asked AI to do this as it's a relatively simple task and I forgot how to do this effectively
+							backend.clients = slices.Delete(backend.clients, clientIndex, clientIndex+1)
-							backend.clients = append(backend.clients[:clientIndex], backend.clients[clientIndex+1:]...)
 							return
 						}
 					}
@@ -288,10 +332,8 @@ func (backend *SSHBackend) StopProxy(command *commonbackend.RemoveProxy) (bool,
 			}
 
 			// Splice out the proxy instance by proxyIndex
-
 			// TODO: change approach. It works but it's a bit wonky imho
-			// I asked AI to do this as it's a relatively simple task and I forgot how to do this effectively
+			backend.proxies = slices.Delete(backend.proxies, proxyIndex, proxyIndex+1)
-			backend.proxies = append(backend.proxies[:proxyIndex], backend.proxies[proxyIndex+1:]...)
 			return true, nil
 		}
 	}
@@ -341,17 +383,31 @@ func (backend *SSHBackend) CheckParametersForBackend(arguments []byte) *commonba
 	}
 }
 
-func (backend *SSHBackend) backendDisconnectHandler() {
+func (backend *SSHBackend) backendKeepaliveHandler() {
 	for {
 		if backend.conn != nil {
-			err := backend.conn.Wait()
+			_, _, err := backend.conn.SendRequest("keepalive@openssh.com", true, nil)
 
-			if err == nil || err.Error() != "EOF" {
+			if err != nil {
-				continue
+				log.Warn("Keepalive message failed!")
+				return
 			}
 		}
 
-		log.Info("Disconnected from the remote SSH server. Attempting to reconnect in 5 seconds...")
+		time.Sleep(5 * time.Second)
+	}
+}
+
+func (backend *SSHBackend) backendDisconnectHandler() {
+	for {
+		if backend.conn != nil {
+			backend.conn.Wait()
+			backend.conn.Close()
+
+			log.Info("Disconnected from the remote SSH server. Attempting to reconnect in 5 seconds...")
+		} else {
+			log.Info("Retrying reconnection in 5 seconds...")
+		}
 
 		time.Sleep(5 * time.Second)
 
@@ -376,14 +432,34 @@ func (backend *SSHBackend) backendDisconnectHandler() {
 			},
 		}
 
-		conn, err := ssh.Dial("tcp", fmt.Sprintf("%s:%d", backend.config.IP, backend.config.Port), config)
+		addr := fmt.Sprintf("%s:%d", backend.config.IP, backend.config.Port)
+		timeout := time.Duration(10 * time.Second)
+
+		rawTCPConn, err := net.DialTimeout("tcp", addr, timeout)
 
 		if err != nil {
-			log.Errorf("Failed to connect to the server: %s", err.Error())
+			log.Errorf("Failed to establish connection to the server: %s", err.Error())
-			return
+			continue
 		}
 
-		backend.conn = conn
+		connWithTimeout := &ConnWithTimeout{
+			Conn:         rawTCPConn,
+			ReadTimeout:  timeout,
+			WriteTimeout: timeout,
+		}
+
+		c, chans, reqs, err := ssh.NewClientConn(connWithTimeout, addr, config)
+
+		if err != nil {
+			log.Errorf("Failed to create SSH client connection: %s", err.Error())
+			rawTCPConn.Close()
+			continue
+		}
+
+		client := ssh.NewClient(c, chans, reqs)
+		backend.conn = client
+
+		go backend.backendKeepaliveHandler()
 
 		log.Info("SSHBackend has reconnected successfully. Attempting to set up proxies again...")