Added option to use bash to verify the connection instead of netcat.

Netcat verification does not work properly with RHEL/CentOS 7.x

Author: Jim Hofer

README.md

@@ -30,8 +30,14 @@ in your `bootstrap/app.php` for Lumen services or add it to your `providers` arr
 ## Configuration
 All configuration can and should be done in your `.env` file.
 ```ini
+; Process used to verify connection
+; Use bash if your distro uses nmap-ncat (RHEL/CentOS 7.x) 
+TUNNELER_VERIFY_PROCESS=nc
+
 ; Path to the nc executable
 TUNNELER_NC_PATH=/usr/bin/nc
+; Path to the bash executable
+TUNNELER_BASH_PATH=/usr/bin/bash
 ; Path to the ssh executable
 TUNNELER_SSH_PATH=/usr/bin/ssh
 ; Path to the nohup executable

config/tunneler.php

@@ -1,6 +1,10 @@
 <?php
 return [
+
+    'verify_process' => env('TUNNELER_VERIFY_PROCESS', 'nc'),
+
     'nc_path' => env('TUNNELER_NC_PATH', 'nc'),
+    'bash_path' => env('TUNNELER_BASH_PATH', 'bash'),
     'ssh_path' => env('TUNNELER_SSH_PATH', 'ssh'),
     'nohup_path' => env('TUNNELER_NOHUP_PATH', 'nohup'),
 
@@ -20,4 +24,5 @@
     'ssh_verbosity' => env('SSH_VERBOSITY',''),
     'ssh_options' => env('TUNNELER_SSH_OPTIONS', ''),
     'nohup_log' => env('NOHUP_LOG', '/dev/null'),
+
 ];

src/Jobs/CreateTunnel.php

@@ -23,12 +23,19 @@ class CreateTunnel
 
     public function __construct()
     {
+
         $this->ncCommand = sprintf('%s -z %s %d  > /dev/null 2>&1',
             config('tunneler.nc_path'),
             config('tunneler.local_address'),
             config('tunneler.local_port')
         );
 
+        $this->bashCommand = sprintf('timeout 1 %s -c \'cat < /dev/null > /dev/tcp/%s/%d\' > /dev/null 2>&1',
+            config('tunneler.bash_path'),
+            config('tunneler.local_address'),
+            config('tunneler.local_port')
+        );
+
         $this->sshCommand = sprintf('%s %s %s -N -i %s -L %d:%s:%d -p %d %s@%s',
             config('tunneler.ssh_path'),
             config('tunneler.ssh_options'),
@@ -46,13 +53,13 @@ public function __construct()
 
     public function handle(): int
     {
-        if ($this->verifyTunnel()){
+        if ($this->verifyTunnel()) {
             return 1;
         }
 
         $this->createTunnel();
 
-        if ($this->verifyTunnel()){
+        if ($this->verifyTunnel()) {
             return 2;
         }
 
@@ -81,6 +88,10 @@ protected function createTunnel()
      */
     protected function verifyTunnel()
     {
+        if (config('tunneler.verify_process') == 'bash') {
+            return $this->runCommand($this->bashCommand);
+        }
+
         return $this->runCommand($this->ncCommand);
     }