def send_msg(datapath, msg, retries=3):
"""
Send a message to the given datapath, with retries on failure.
Prefer the higher-level functions in flows.py before dropping down to
send_msg.
Args:
datapath (ryu.controller.controller.Datapath): The datapath to send the
message to
msg: Openflow message to send
retries: Number of retries on failure
Raises:
MagmaOFError: if the message fails to send in the specified number of
attempts
"""
for i in range(0, retries):
try:
datapath.send_msg(msg)
return
except Exception as e: # pylint: disable=broad-except
logger.warning(
'Error sending message, retrying again '
'(attempt %s/%s)', i, retries,
)
if i == retries - 1: # Only propagate if all retries are up
logging.error('Send msg error! Type: %s, Reason: %s',
type(e).__name__, e)
DP_SEND_MSG_ERROR.labels(cause=type(e).__name__).inc()
raise MagmaOFError(e)
else:
continue
def _get_encoded_imsi_from_packetin(msg):
"""
Retrieve encoded imsi from the Packet-In message, or raise an exception if
it doesn't exist.
"""
imsi = msg.match.get(IMSI_REG)
if imsi is None:
raise MagmaOFError('IMSI not found in OFPMatch')
return imsi
def handle_error(self, ev):
"""
Error means that a message sent to OVS is unsuccessful. This function
should be attached to the EventOFPErrorMsg event
"""
msg = ev.msg
datapath = msg.datapath
switch = self._switches.get(datapath.id, None)
if switch is None:
self.logger.error('unknown dpid %s', datapath.id)
return
if msg.xid not in switch.results_by_msg:
return
# for now, result is unused. Just return if there's an exception
switch.results_by_msg[msg.xid] = MagmaOFError(ev.msg)
