def receive_msg(sock):
"""
Method by which a byte message is decoded
:param sock: tcp socket to read from
:return: a dict of the decoded values
"""
msg_hdr = sock.recv(4)
if len(msg_hdr) is 0:
raise GossipClientDisconnectedException('Client disconnected')
elif len(msg_hdr) < 4:
raise GossipMessageException('Invalid header (< 4)')
# the first and the second byte encode the message length
size_fst, size_snd = struct.unpack('{}B'.format(2), msg_hdr[:2])
size = bytes_to_short(size_fst, size_snd)
if size < 4:
raise GossipMessageException('Invalid size (< 4)')
# third and forth byte encode the message code
msg_code_fst, msg_code_snd = struct.unpack('{}B'.format(2), msg_hdr[2:4])
code = bytes_to_short(msg_code_fst, msg_code_snd)
if not MESSAGE_CODE_GOSSIP_MIN <= code < MESSAGE_CODE_GOSSIP_MAX:
raise GossipMessageException('Invalid message code')
data = sock.recv(size - 4)
logging.info('Received message: %d | %d | %s' % (size, code, data))
msg = {'size': size, 'code': code, 'message': data}
return msg
def test_bytes_to_short():
short_first = byte_formatting.bytes_to_short(0xff, 0xff)
short_second = byte_formatting.bytes_to_short(0x00, 0x00)
short_third = byte_formatting.bytes_to_short(0x0f, 0x9f)
short_fourth = byte_formatting.bytes_to_short(0x00, 0xff)
assert short_first == 65535
assert short_second == 0
assert short_third == 3999
assert short_fourth == 255
def __init__(self, data):
"""
C'Tor
:param bytes data: the data from this message
"""
super().__init__(MESSAGE_CODE_NOTIFICATION, data)
msg_id_fst, msg_id_snd = struct.unpack('{}B'.format(2), data[:2])
self.msg_id = bytes_to_short(msg_id_fst, msg_id_snd)
data_type_fst, data_type_snd = struct.unpack('{}B'.format(2),
data[2:4])
self.data_type = bytes_to_short(data_type_fst, data_type_snd)
self.msg = struct.unpack('{}B'.format(len(data) - 4),
data[4:len(data)])
def __init__(self, data):
"""
C'Tor
:param bytes data: the data of the message
"""
super().__init__(MESSAGE_CODE_NOTIFY, data)
data_type_fst, data_type_snd = struct.unpack('{}B'.format(2),
data[2:4])
self.data_type = bytes_to_short(data_type_fst, data_type_snd)
def __init__(self, data):
"""
C'Tor
:param bytes data: the data of the message
"""
super().__init__(MESSAGE_CODE_ANNOUNCE, data)
self.ttl = struct.unpack('{}B'.format(1), data[:1])[0]
data_type_fst, data_type_snd = struct.unpack('{}B'.format(2),
data[2:4])
self.data_type = bytes_to_short(data_type_fst, data_type_snd)
self.msg = struct.unpack('{}B'.format(len(data) - 4),
data[4:len(data)])
def __init__(self, data):
"""
C'Tor
:param data: the data from this message
"""
super().__init__(MESSAGE_CODE_VALIDATION, data)
msg_id_fst, msg_id_snd = struct.unpack('{}B'.format(2), data[:2])
self.msg_id = bytes_to_short(msg_id_fst, msg_id_snd)
_, valid = struct.unpack('{}B'.format(2), data[2:4])
if valid == 0:
self.valid = False
else:
self.valid = True
def __init__(self, data):
"""
C'Tor
:param data: the data from this message
"""
super().__init__(MESSAGE_CODE_PEER_INIT, data)
self.data = data
ipv4_part_1 = int(self.data[0])
ipv4_part_2 = int(self.data[1])
ipv4_part_3 = int(self.data[2])
ipv4_part_4 = int(self.data[3])
port = bytes_to_short(self.data[4], self.data[5])
self.address = '%s.%s.%s.%s:%s' % (ipv4_part_1, ipv4_part_2,
ipv4_part_3, ipv4_part_4, port)
def __init__(self, data):
"""
C'Tor
:param data: the data from this message
"""
super().__init__(MESSAGE_CODE_PEER_RESPONSE, data)
self.data = data
self.connections = []
if len(self.data) > 0:
data = struct.unpack('{}B'.format(len(self.data)), self.data)
for i in range(0, len(self.data), 6):
ipv4_part_1 = int(data[i])
ipv4_part_2 = int(data[i + 1])
ipv4_part_3 = int(data[i + 2])
ipv4_part_4 = int(data[i + 3])
port = bytes_to_short(self.data[i + 4], self.data[i + 5])
address = '%s.%s.%s.%s:%s' % (ipv4_part_1, ipv4_part_2,
ipv4_part_3, ipv4_part_4, port)
self.connections.append(address)
