[dtls] eliminate more exceptions, just set state to failed

Author: jlaine

aiortc/rtcdtlstransport.py

@@ -324,8 +324,9 @@ async def start(self, remoteParameters):
                 if error == lib.SSL_ERROR_WANT_READ:
                     await self._recv_next()
                 else:
+                    self.__log_debug('x DTLS handshake failed (error %d)', error)
                     self._set_state(State.FAILED)
-                    raise DtlsError('DTLS handshake failed (error %d)' % error)
+                    return
         except ConnectionError:
             self.__log_debug('x DTLS handshake failed (connection error)')
             self._set_state(State.FAILED)
@@ -340,8 +341,9 @@ async def start(self, remoteParameters):
                 fingerprint_is_valid = True
                 break
         if not fingerprint_is_valid:
+            self.__log_debug('x DTLS handshake failed (fingerprint mismatch)')
             self._set_state(State.FAILED)
-            raise DtlsError('DTLS fingerprint does not match')
+            return
 
         # generate keying material
         buf = ffi.new('unsigned char[]', 2 * (SRTP_KEY_LEN + SRTP_SALT_LEN))

tests/test_dtls.py

@@ -233,13 +233,11 @@ def test_bad_client_fingerprint(self):
 
         bogus_parameters = RTCDtlsParameters(
             fingerprints=[RTCDtlsFingerprint(algorithm='sha-256', value='bogus_fingerprint')])
-        with self.assertRaises(DtlsError) as cm:
-            run(asyncio.gather(
-                session1.start(bogus_parameters),
-                session2.start(session1.getLocalParameters())))
-        self.assertEqual(str(cm.exception), 'DTLS fingerprint does not match')
+        run(asyncio.gather(
+            session1.start(bogus_parameters),
+            session2.start(session1.getLocalParameters())))
         self.assertEqual(session1.state, 'failed')
-        self.assertEqual(session2.state, 'connecting')
+        self.assertEqual(session2.state, 'connected')
 
         run(session1.stop())
         run(session2.stop())
@@ -258,11 +256,9 @@ def test_handshake_error(self, mock_get_error, mock_do_handshake):
         certificate2 = RTCCertificate.generateCertificate()
         session2 = RTCDtlsTransport(transport2, [certificate2])
 
-        with self.assertRaises(DtlsError) as cm:
-            run(asyncio.gather(
-                session1.start(session2.getLocalParameters()),
-                session2.start(session1.getLocalParameters())))
-        self.assertEqual(str(cm.exception), 'DTLS handshake failed (error 1)')
+        run(asyncio.gather(
+            session1.start(session2.getLocalParameters()),
+            session2.start(session1.getLocalParameters())))
         self.assertEqual(session1.state, 'failed')
         self.assertEqual(session2.state, 'failed')