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isotp error handler not propagated to uds connection #233
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In general i might be that the protocol._stop_receiving() or _stop_sending() call is not propagated to the listener. not all error_handler calls abort the reception.
Did the following hack to work around it:
class Connection(PythonIsoTpConnection): def transport_error(self, exception: Exception): self.fromIsoTPQueue.put(exception) def specific_wait_frame(self, timeout=2): if not self.opened: raise RuntimeError("Connection is not open") frame = None try: frame = self.fromIsoTPQueue.get(block=True, timeout=timeout) except queue.Empty as exception: raise TimeoutException("Did not receive frame IsoTP Transport layer in time (timeout=%s sec)" % timeout) from exception if isinstance(frame, Exception): raise frame if self.mtu is not None: if frame is not None and len(frame) > self.mtu: self.logger.warning("Truncating received payload to a length of %d" % (self.mtu)) frame = frame[0:self.mtu] return bytes(frame) # isotp.protocol.TransportLayer uses bytearray. udsoncan is strict on bytes formatThen hook that transport error into the isotp.CanStack.
connection: Connection def transport_error(exception: Exception): connection.transport_error(exception) transport = isotp.CanStack( self.bus, address=isotp_addr, params=isotp_params, error_handler=transport_error, ) connection = Connection(transport)But it gets ugly due to when and how the transport_error is registered. Maybe the recv() function of isotp should be changed to propagate these exceptions? In my case it's usually been "FlowControlTimeoutError: Reception of FlowControl timed out. Stopping transmission" that causes issues.
Thanks, I see what you mean. The error should be reported to the upper layer.
I will check this, but maybe not short term.
When a isotp error occurs, it triggers a call to a callback, that one can supply to the constructor of the isotp stack called
error_handler. The default of this callback is to just log an message to log.The uds stack should be informed of this error and abort on-going requests in PythonIsoTpConnection.specific_wait_frame. With log request timeouts, it can take a long time for the request to abort. It also aborts with a TimeoutException instead of the actual low level fault.