Improve error messages for failed TCP/IP connections with errno/errstr

Author: clue

src/TcpConnector.php

@@ -99,9 +99,20 @@ public function connect($uri)
                 // The following hack looks like the only way to
                 // detect connection refused errors with PHP's stream sockets.
                 if (false === \stream_socket_get_name($stream, true)) {
-                    \fclose($stream);
+                    // actual socket errno and errstr can only be retrieved when ext-sockets is available (see tests)
+                    // @codeCoverageIgnoreStart
+                    if (\function_exists('socket_import_stream')) {
+                        $socket = \socket_import_stream($stream);
+                        $errno = \socket_get_option($socket, \SOL_SOCKET, \SO_ERROR);
+                        $errstr = \socket_strerror($errno);
+                    } else {
+                        $errno = \defined('SOCKET_ECONNREFUSED') ? \SOCKET_ECONNRESET : 111;
+                        $errstr = 'Connection refused?';
+                    }
+                    // @codeCoverageIgnoreEnd
 
-                    $reject(new \RuntimeException('Connection to ' . $uri . ' failed: Connection refused'));
+                    \fclose($stream);
+                    $reject(new \RuntimeException('Connection to ' . $uri . ' failed: ' . $errstr, $errno));
                 } else {
                     $resolve(new Connection($stream, $loop));
                 }

tests/TcpConnectorTest.php

@@ -100,6 +100,39 @@ public function connectionToTcpServerShouldFailIfFileDescriptorsAreExceeded()
         Block\await($connector->connect('127.0.0.1:9999'), $loop, self::TIMEOUT);
     }
 
+    /** @test */
+    public function connectionToInvalidNetworkShouldFailWithUnreachableError()
+    {
+        if (!defined('SOCKET_ENETUNREACH') || !function_exists('socket_import_stream')) {
+            $this->markTestSkipped('Test requires ext-socket on PHP 5.4+');
+        }
+
+        // try to find an unreachable network by trying a couple of private network addresses
+        $errno = 0; $errstr = '';
+        for ($i = 0; $i < 20; ++$i) {
+            $address = 'tcp://192.168.' . mt_rand(0, 255) . '.' . mt_rand(1, 254) . ':8123';
+            $client = @stream_socket_client($address, $errno, $errstr, 0.1 * $i);
+            if ($errno === SOCKET_ENETUNREACH) {
+                break;
+            }
+        }
+        if ($client || $errno !== SOCKET_ENETUNREACH) {
+            $this->markTestSkipped('Expected error ' . SOCKET_ENETUNREACH . ' but got ' . $errno . ' (' . $errstr . ') for ' . $address);
+        }
+
+        $loop = Factory::create();
+        $connector = new TcpConnector($loop);
+
+        $promise = $connector->connect($address);
+
+        $this->setExpectedException(
+            'RuntimeException',
+            'Connection to ' . $address . ' failed: ' . socket_strerror(SOCKET_ENETUNREACH),
+            SOCKET_ENETUNREACH
+        );
+        Block\await($promise, $loop, self::TIMEOUT);
+    }
+
     /** @test */
     public function connectionToTcpServerShouldSucceedWithRemoteAdressSameAsTarget()
     {