ixxat: Raise exception on busoff in recv() (hardbyte#856)

Author: henzef

can/interfaces/ixxat/canlib.py

@@ -29,6 +29,7 @@
 __all__ = [
     "VCITimeout",
     "VCIError",
+    "VCIBusOffError",
     "VCIDeviceNotFoundError",
     "IXXATBus",
     "vciFormatError",
@@ -354,6 +355,15 @@ def __check_status(result, function, arguments):
     constants.CAN_ERROR_CRC: "CAN CRC error",
     constants.CAN_ERROR_OTHER: "Other (unknown) CAN error",
 }
+
+CAN_STATUS_FLAGS = {
+    constants.CAN_STATUS_TXPEND: "transmission pending",
+    constants.CAN_STATUS_OVRRUN: "data overrun occurred",
+    constants.CAN_STATUS_ERRLIM: "error warning limit exceeded",
+    constants.CAN_STATUS_BUSOFF: "bus off",
+    constants.CAN_STATUS_ININIT: "init mode active",
+    constants.CAN_STATUS_BUSCERR: "bus coupling error",
+}
 # ----------------------------------------------------------------------------
 
 
@@ -644,6 +654,13 @@ def _recv_internal(self, timeout):
                             )
                         )
 
+                    elif (
+                        self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_STATUS
+                    ):
+                        log.info(_format_can_status(self._message.abData[0]))
+                        if self._message.abData[0] & constants.CAN_STATUS_BUSOFF:
+                            raise VCIBusOffError()
+
                     elif (
                         self._message.uMsgInfo.Bits.type
                         == constants.CAN_MSGTYPE_TIMEOVR
@@ -761,3 +778,25 @@ def stop(self):
         # the list with permanently stopped messages
         _canlib.canSchedulerRemMessage(self._scheduler, self._index)
         self._index = None
+
+
+def _format_can_status(status_flags: int):
+    """
+    Format a status bitfield found in CAN_MSGTYPE_STATUS messages or in dwStatus
+    field in CANLINESTATUS.
+
+    Valid states are defined in the CAN_STATUS_* constants in cantype.h
+    """
+    states = []
+    for flag, description in CAN_STATUS_FLAGS.items():
+        if status_flags & flag:
+            states.append(description)
+            status_flags &= ~flag
+
+    if status_flags:
+        states.append("unknown state 0x{:02x}".format(status_flags))
+
+    if states:
+        return "CAN status message: {}".format(", ".join(states))
+    else:
+        return "Empty CAN status message"

can/interfaces/ixxat/exceptions.py

@@ -6,7 +6,13 @@
 
 from can import CanError
 
-__all__ = ["VCITimeout", "VCIError", "VCIRxQueueEmptyError", "VCIDeviceNotFoundError"]
+__all__ = [
+    "VCITimeout",
+    "VCIError",
+    "VCIRxQueueEmptyError",
+    "VCIBusOffError",
+    "VCIDeviceNotFoundError",
+]
 
 
 class VCITimeout(CanError):
@@ -24,5 +30,10 @@ def __init__(self):
         super().__init__("Receive queue is empty")
 
 
+class VCIBusOffError(VCIError):
+    def __init__(self):
+        super().__init__("Controller is in BUSOFF state")
+
+
 class VCIDeviceNotFoundError(CanError):
     pass