def snmp_server(self):
"""
SNMP server coroutine
:return:
"""
self.logger.info("Stating BEEF SNMP server")
yield self.server_iostream.connect()
decoder = BERDecoder()
encoder = BEREncoder()
while True:
# Wait for SNMP request
request = yield self.server_iostream.read_bytes(self.MAX_REQUEST_SIZE, partial=True)
pdu = decoder.parse_sequence(request)[0]
self.logger.info("SNMP REQUEST: %r", pdu)
version = pdu[0]
community = pdu[1]
pdu_type = pdu[2][0]
request_id = pdu[2][1]
if pdu_type == PDU_GET_REQUEST:
err_status, err_index, data = self.snmp_get_response(pdu)
elif pdu_type == PDU_GETNEXT_REQUEST:
err_status, err_index, data = self.snmp_getnext_response(pdu)
elif pdu_type == PDU_GETBULK_REQUEST:
err_status, err_index, data = self.snmp_getbulk_response(pdu)
else:
# @todo: Unsupported PDU type
pass
# Build response
resp = encoder.encode_sequence(
[
encoder.encode_int(version),
encoder.encode_octet_string(community),
encoder.encode_choice(
PDU_RESPONSE,
[
encoder.encode_int(request_id),
encoder.encode_int(err_status),
encoder.encode_int(err_index),
encoder.encode_sequence(
[
encoder.encode_sequence([encoder.encode_oid(str(oid)), value])
for oid, value in data
]
),
],
),
]
)
self.logger.info("RESPONSE = %r", data)
yield self.server_iostream.write(resp)
async def send_and_receive(
self, data: bytes,
address: Tuple[str, int]) -> Tuple[bytes, Tuple[str, int]]:
pdu = BERDecoder().parse_sequence(data)[0]
self.logger.info("SNMP REQUEST: %r", pdu)
version = pdu[0]
community = pdu[1]
pdu_type = pdu[2][0]
request_id = pdu[2][1]
if pdu_type == PDU_GET_REQUEST:
err_status, err_index, data = self.snmp_get_response(pdu)
elif pdu_type == PDU_GETNEXT_REQUEST:
err_status, err_index, data = self.snmp_getnext_response(pdu)
elif pdu_type == PDU_GETBULK_REQUEST:
err_status, err_index, data = self.snmp_getbulk_response(pdu)
else:
raise ScriptError("Unknown PDU type")
# Build response
encoder = BEREncoder()
response = encoder.encode_sequence([
encoder.encode_int(version),
encoder.encode_octet_string(community),
encoder.encode_choice(
PDU_RESPONSE,
[
encoder.encode_int(request_id),
encoder.encode_int(err_status),
encoder.encode_int(err_index),
encoder.encode_sequence([
encoder.encode_sequence(
[encoder.encode_oid(str(oid)),
smart_bytes(value)]) for oid, value in data
]),
],
),
])
self.logger.info("RESPONSE = %r", data)
return response, address
def test_encode_octet_string(raw, value):
encoder = BEREncoder()
assert encoder.encode_octet_string(raw) == value