def handle_recv(self, pair):
station, packet = pair
message = PIAMessage()
stream = StreamIn(packet.payload, self.settings)
while not stream.eof():
peek = stream.peek(stream.available())
if all(x == 0xFF for x in peek):
break
message = message.copy()
if not self.encoder.decode(stream, message):
return
if message.flags & 0x10:
message.payload = zlib.decompress(message.payload)
if station.id is None:
station.id = message.station_id
elif station.id != message.station_id:
logger.error("Received message with wrong station id")
return
self.messages.append((station, message))
def parse_browse_reply(self, data, key, challenge):
stream = StreamIn(data, self.settings)
if stream.u8() != 1:
return None
size = stream.u32()
data = stream.read(size)
if not self.verify_challenge_reply(stream, key, challenge):
return None
if not stream.eof():
logger.warning("Browse reply is bigger than expected")
return None
stream = StreamIn(data, self.settings)
try:
session_info = stream.extract(LanSessionInfo)
except Exception as e:
logger.warning("Failed to parse LanSessionInfo: %s", e)
return None
if not stream.eof():
logger.warning("LanSessionInfo has unexpected size")
return None
return session_info
def handle_ack(self, station, data):
logger.debug("Received ack")
stream = StreamIn(data, self.settings)
stream.skip(4)
ack_id = stream.u32()
self.resender.acknowledge(station, ack_id)
def decode(self, stream):
if stream.settings.get("pia.version") < 51000:
self.connection_info = stream.extract(StationConnectionInfo)
else:
substream = StreamIn(stream.read(0x3E), stream.settings)
location = substream.extract(StationLocation)
self.connection_info = StationConnectionInfo(location)
self.index = stream.u8()
stream.align(4)
def handle_session_reply(self, station, data):
logger.debug("Received session reply")
stream = StreamIn(data, self.settings)
stream.skip(12)
session_id = stream.u32()
if session_id not in self.host_requests:
logger.warning("Received unexpected session reply")
return
self.session_requests[session_id].update(stream)
def parse_browse_reply(self, data, key, challenge):
stream = StreamIn(data, self.settings)
if stream.u8() != 1:
return None
if stream.size() != 0x551:
logger.warning(
"Browse reply has unexpected size (expected 1361 bytes, got %i)"
% stream.size())
return None
size = stream.u32()
if size != 0x512:
logger.warning(
"LanSessionInfo has unexpected size (expected 1298 bytes, got %i)"
% size)
return None
try:
session_info = stream.extract(LanSessionInfo)
except Exception as e:
import traceback
traceback.print_exc()
logger.warning("Failed to parse LanSessionInfo: %s", e)
return None
if not self.verify_challenge_reply(stream, key, challenge):
return None
return session_info
def handle_join_response(self, station, data):
logger.debug("Received join response")
if self.join_response_parser is None:
logger.error("Received unexpected join response")
return
if data[1] == 0:
reason = data[4]
logger.error("Join request was denied: %i", reason)
self.join_response_parser.error = True
return
stream = StreamIn(data, self.settings)
stream.skip(1)
if self.join_response_parser.update(stream):
ack_id = stream.u32()
self.station_protocol.send_ack(station, ack_id)
def handle_connection_response(self, station, data):
logger.debug("Received connection response")
if station.connection_state not in [ConnectionState.WAIT_RESPONSE, ConnectionState.WAIT_INVERSE_RESPONSE]:
logger.error("Received unexpected connection response")
return
stream = StreamIn(data, self.settings)
stream.skip(1)
identification = self.process_connection_response(stream)
if identification is not None:
ack_id = stream.u32()
self.send_ack(station, ack_id)
station.identification_info = identification
if station.connection_state == ConnectionState.WAIT_INVERSE_RESPONSE:
self.send_connection_response(station)
station.connection_state = ConnectionState.CONNECTED
else:
station.connection_state = ConnectionState.ERROR
def handle_session_request(self, station, data):
logger.debug("Received session request")
if len(data) != 0x10:
logger.error("Session request has unexpected size")
return
stream = StreamIn(data, self.settings)
stream.skip(12)
session_id = stream.u32()
session_info = self.session.get_session_info()
if session_info.session_id != session_id:
logger.warning("Received session request with different session id")
return
if not self.session.is_host():
logger.info("Ignoring session request because we aren't host")
return
self.send_session_reply(station, session_info)
def handle_host_reply(self, station, data):
logger.debug("Received host reply")
stream = StreamIn(data, self.settings)
stream.skip(12)
session_id = stream.u32()
if self.settings.get("pia.version") < 51000:
host = stream.extract(StationConnectionInfo).public
else:
host = stream.extract(StationLocation)
if session_id not in self.host_requests:
logger.warning("Received unexpected host reply")
return
self.host_requests[session_id] = host
def parse_browse_request(self, data):
stream = StreamIn(data, self.settings)
if stream.u8() != 0:
logger.debug("Message is not a browse request")
return None
size = stream.u32()
end = stream.tell() + size
criteria = stream.extract(LanSessionSearchCriteria)
if stream.tell() != end:
logger.warning("LanSessionSearchCriteria has unexpected size")
return None
reply = self.parse_challenge(stream)
if reply is None:
return None
if not stream.eof():
logger.warning("Browse request is bigger than expected")
return None
logger.info("Received browse request")
return criteria, reply
def decode(self, data):
data = self.check_signature(data)
if data is None:
logger.error("Invalid packet signature")
return False
stream = StreamIn(data, self.settings)
if stream.u32() != 0x32AB9864:
logger.error("Invalid packet identifier")
return False
if self.settings.get("pia.header_version") > 0:
byte = stream.u8()
encrypted = byte >> 7
version = byte & 0x7F
if version != self.settings.get("pia.header_version"):
logger.error("Unexpected packet version: %i", version)
return False
else:
encryption = stream.u8()
if encryption not in [1, 2]:
logger.error("Invalid encryption mode")
return False
encrypted = encryption == 2
self.connection_id = stream.u8()
self.sequence_id = stream.u16()
if self.settings.get("pia.header_version") == 0:
self.session_timer = stream.u16()
self.rtt_timer = stream.u16()
if self.settings.get(
"pia.encryption_method") == EncryptionMethod.AES_GCM:
self.nonce = stream.u64()
self.signature = stream.read(16)
payload = stream.read(stream.available())
if encrypted:
payload = self.decrypt(payload)
if payload is None:
return False
self.payload = payload
return True
def handle_connection_request(self, station, data):
logger.debug("Received connection request")
stream = StreamIn(data, self.settings)
stream.skip(1)
connection_id = stream.u8()
version = stream.u8()
inverse = stream.bool()
if version != self.version:
logger.error(
"Received connection request with wrong version number")
self.send_denying_connection_response(station, 2)
return
local_station = self.session.local_station()
local_info = local_station.connection_info.local
if self.version >= 7:
if stream.pid() != local_info.pid:
logger.error("Received connection request with wrong pid")
return
if self.version >= 8:
if stream.u32() != local_info.cid:
logger.error("Received connection request with wrong cid")
return
inverse_id = stream.u8()
if inverse_id != station.connection_id_out_temp:
logger.error(
"Received connection request with wrong inverse connection id: %i",
inverse_id)
return
if self.version == 8:
conn_info = stream.extract(StationConnectionInfo)
else:
location = stream.extract(StationLocation)
conn_info = StationConnectionInfo(location)
ack_id = stream.u32()
if inverse:
if station.connection_state != ConnectionState.WAIT_INVERSE_REQUEST:
logger.error("Received unexpected inverse connection request")
self.send_denying_connection_response(station, 1)
return
station.connection_id_in_temp = connection_id
station.connection_info = conn_info
self.send_ack(station, ack_id)
self.send_connection_response(station)
station.connection_state = ConnectionState.WAIT_RESPONSE
else:
if station.connection_state != ConnectionState.DISCONNECTED:
logger.error("Received unexpected connection request")
self.send_denying_connection_response(station, 1)
return
station.connection_id_out_temp = random.randint(2, 0xFF)
station.connection_id_in_temp = connection_id
station.connection_info = conn_info
self.send_ack(station, ack_id)
self.send_connection_request(station, connection_id)
station.connection_state = ConnectionState.WAIT_INVERSE_RESPONSE
