startTLS: avoid retrying TLS connection if hostname is an IP address

syncplay/client.py

@@ -706,10 +706,14 @@ class SyncplayClient(object):
         if '[' in host:
             host = host.strip('[]')
         port = int(port)
-        with open('cert/server.crt') as cert_file:
-            trust_root = Certificate.loadPEM(cert_file.read())
         self._endpoint = HostnameEndpoint(reactor, host, port)
-        self.protocolFactory.options = optionsForClientTLS(hostname=host, trustRoot = trust_root)
+        try:
+            with open('cert/server.crt') as cert_file:
+                trust_root = Certificate.loadPEM(cert_file.read())
+            self.protocolFactory.options = optionsForClientTLS(hostname=host, trustRoot = trust_root)
+        except Exception as e:
+            self.protocolFactory.options = None
+            self._serverSupportsTLS = False
 
         def retry(retries):
             self._lastGlobalUpdate = None

syncplay/protocols.py

@@ -78,9 +78,15 @@ class SyncClientProtocol(JSONCommandProtocol):
             self.sendTLS({"startTLS": "send"})
             self._client.ui.showMessage("Attempting secure connection")
         else:
+            self._client.ui.showErrorMessage("This server does not support TLS")
             self.sendHello()
 
     def connectionLost(self, reason):
+        try:
+            if "Invalid DNS-ID" in str(reason.value):
+                self._client._serverSupportsTLS = False
+        except:
+            pass
         self._client.destroyProtocol()
 
     def dropWithError(self, error):
@@ -303,7 +309,6 @@ class SyncClientProtocol(JSONCommandProtocol):
 
     def handleError(self, error):
         if "startTLS" in error["message"] and not self.logged:
-            self._client.ui.showErrorMessage("This server does not support TLS")
             self._client._serverSupportsTLS = False
         else:
             self.dropWithError(error["message"])

syncplayServer.py

@@ -13,7 +13,6 @@ except AttributeError:
     import warnings
     warnings.warn("You must run Syncplay with Python 3.4 or newer!")
 
-from OpenSSL import crypto
 from twisted.internet import reactor
 from twisted.internet.endpoints import TCP4ServerEndpoint, TCP6ServerEndpoint