pyCraft/minecraft/networking/connection.py

620 lines
24 KiB
Python

from __future__ import print_function
from collections import deque
from threading import Lock
from zlib import decompress
import threading
import socket
import time
import timeit
import select
import sys
import json
from future.utils import raise_
from .types import VarInt
from . import packets
from . import encryption
from .. import SUPPORTED_PROTOCOL_VERSIONS
from .. import SUPPORTED_MINECRAFT_VERSIONS
from ..exceptions import VersionMismatch
STATE_STATUS = 1
STATE_PLAYING = 2
class ConnectionContext(object):
"""A ConnectionContext encapsulates the static configuration parameters
shared by the Connection class with other classes, such as Packet.
Importantly, it can be used without knowing the interface of Connection.
"""
def __init__(self, **kwds):
self.protocol_version = kwds.get('protocol_version')
class _ConnectionOptions(object):
def __init__(self, address=None, port=None, compression_threshold=-1,
compression_enabled=False):
self.address = address
self.port = port
self.compression_threshold = compression_threshold
self.compression_enabled = compression_enabled
class Connection(object):
"""This class represents a connection to a minecraft
server, it handles everything from connecting, sending packets to
handling default network behaviour
"""
def __init__(
self,
address,
port=25565,
auth_token=None,
username=None,
initial_version=None,
allowed_versions=None,
handle_exception=None,
):
"""Sets up an instance of this object to be able to connect to a
minecraft server.
The connect method needs to be called in order to actually begin
the connection
:param address: address of the server to connect to
:param port(int): port of the server to connect to
:param auth_token: :class:`minecraft.authentication.AuthenticationToken`
object. If None, no authentication is attempted and
the server is assumed to be running in offline mode.
:param username: Username string; only applicable in offline mode.
:param initial_version: A Minecraft version string or protocol version
number to use if the server's protocol version
cannot be determined. (Although it is now
somewhat inaccurate, this name is retained for
backward compatibility.)
:param allowed_versions: A set of versions, each being a Minecraft
version string or protocol version number,
restricting the versions that the client may
use in connecting to the server.
:param handle_exception: A function to be called when an exception
occurs in the client's networking thread,
taking 2 arguments: the exception object 'e'
as in 'except Exception as e', and a 3-tuple
given by sys.exc_info(); or None for the
default behaviour of raising the exception
from its original context; or False for no
action. In any case, the networking thread
will terminate, the exception will be
available via the 'exception' and 'exc_info'
attributes of the 'Connection' instance.
""" # NOQA
self._write_lock = Lock()
self.networking_thread = None
self.packet_listeners = []
def proto_version(version):
if isinstance(version, str):
proto_version = SUPPORTED_MINECRAFT_VERSIONS.get(version)
elif isinstance(version, int):
proto_version = version
else:
proto_version = None
if proto_version not in SUPPORTED_PROTOCOL_VERSIONS:
raise ValueError('Unsupported version number: %r.' % version)
return proto_version
if allowed_versions is None:
self.allowed_proto_versions = set(SUPPORTED_PROTOCOL_VERSIONS)
else:
allowed_versions = set(map(proto_version, allowed_versions))
self.allowed_proto_versions = allowed_versions
if initial_version is None:
self.default_proto_version = max(self.allowed_proto_versions)
else:
self.default_proto_version = proto_version(initial_version)
self.context = ConnectionContext(
protocol_version=max(self.allowed_proto_versions))
self.options = _ConnectionOptions()
self.options.address = address
self.options.port = port
self.auth_token = auth_token
self.username = username
self.handle_exception = handle_exception
self.exception, self.exc_info = None, None
# The reactor handles all the default responses to packets,
# it should be changed per networking state
self.reactor = PacketReactor(self)
def _start_network_thread(self):
"""May safely be called multiple times."""
if self.networking_thread is None:
self.networking_thread = NetworkingThread(self)
self.networking_thread.start()
elif self.networking_thread.interrupt:
# This thread will wait until the previous thread exits, and then
# set `networking_thread' to itself.
NetworkingThread(self, previous=self.networking_thread).start()
def write_packet(self, packet, force=False):
"""Writes a packet to the server.
If force is set to true, the method attempts to acquire the write lock
and write the packet out immediately, and as such may block.
If force is false then the packet will be added to the end of the
packet writing queue to be sent 'as soon as possible'
:param packet: The :class:`network.packets.Packet` to write
:param force(bool): Specifies if the packet write should be immediate
"""
packet.context = self.context
if force:
self._write_lock.acquire()
if self.options.compression_enabled:
packet.write(self.socket, self.options.compression_threshold)
else:
packet.write(self.socket)
self._write_lock.release()
else:
self._outgoing_packet_queue.append(packet)
def register_packet_listener(self, method, *args):
"""
Registers a listener method which will be notified when a packet of
a selected type is received
:param method: The method which will be called back with the packet
:param args: The packets to listen for
"""
self.packet_listeners.append(packets.PacketListener(method, *args))
def _pop_packet(self):
# Pops the topmost packet off the outgoing queue and writes it out
# through the socket
#
# Mostly an internal convenience function, caller should make sure
# they have the write lock acquired to avoid issues caused by
# asynchronous access to the socket.
# This should be the only method that removes elements from the
# outbound queue
if len(self._outgoing_packet_queue) == 0:
return False
else:
packet = self._outgoing_packet_queue.popleft()
if self.options.compression_enabled:
packet.write(self.socket, self.options.compression_threshold)
else:
packet.write(self.socket)
return True
def status(self, handle_status=None, handle_ping=False):
"""Issue a status request to the server and then disconnect.
:param handle_status: a function to be called with the status
dictionary None for the default behaviour of
printing the dictionary to standard output, or
False to ignore the result.
:param handle_ping: a function to be called with the measured latency
in milliseconds, None for the default handler,
which prints the latency to standard outout, or
False, to prevent measurement of the latency.
"""
self._connect()
self._handshake(next_state=STATE_STATUS)
self._start_network_thread()
self.reactor = StatusReactor(self, do_ping=handle_ping is not False)
if handle_status is False:
self.reactor.handle_status = lambda *args, **kwds: None
elif handle_status is not None:
self.reactor.handle_status = handle_status
if handle_ping is False:
self.reactor.handle_ping = lambda *args, **kwds: None
elif handle_ping is not None:
self.reactor.handle_ping = handle_ping
request_packet = packets.RequestPacket()
self.write_packet(request_packet)
def connect(self):
"""
Attempt to begin connecting to the server.
May safely be called multiple times after the first, i.e. to reconnect.
"""
# Hold the lock throughout, in case connect() is called from the
# networking thread while another connection is in progress.
with self._write_lock: # pylint: disable=not-context-manager
# It is important that this is set correctly even when connecting
# in status mode, as some servers, e.g. SpigotMC with the
# ProtocolSupport plugin, use it to determine the correct response.
self.context.protocol_version = max(self.allowed_proto_versions)
self.spawned = False
self._connect()
if len(self.allowed_proto_versions) == 1:
# There is exactly one allowed protocol version, so skip the
# process of determining the server's version, and immediately
# connect.
self._handshake(next_state=STATE_PLAYING)
login_start_packet = packets.LoginStartPacket()
if self.auth_token:
login_start_packet.name = self.auth_token.profile.name
else:
login_start_packet.name = self.username
self.write_packet(login_start_packet)
self.reactor = LoginReactor(self)
else:
# Determine the server's protocol version by first performing a
# status query.
self._handshake(next_state=STATE_STATUS)
self.write_packet(packets.RequestPacket())
self.reactor = PlayingStatusReactor(self)
self._start_network_thread()
def _connect(self):
# Connect a socket to the server and create a file object from the
# socket.
# The file object is used to read any and all data from the socket
# since it's "guaranteed" to read the number of bytes specified,
# the socket itself will mostly be used to write data upstream to
# the server.
self._outgoing_packet_queue = deque()
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.connect((self.options.address, self.options.port))
self.file_object = self.socket.makefile("rb", 0)
def disconnect(self):
""" Terminate the existing server connection, if there is one. """
if self.networking_thread is not None:
with self._write_lock: # pylint: disable=not-context-manager
self.networking_thread.interrupt = True
if self.socket is not None:
if hasattr(self.socket, 'actual_socket'):
# pylint: disable=no-member
actual_socket = self.socket.actual_socket
else:
actual_socket = self.socket
try:
actual_socket.shutdown(socket.SHUT_RDWR)
except socket.error:
pass
finally:
actual_socket.close()
self.socket = None
def _handshake(self, next_state=STATE_PLAYING):
handshake = packets.HandShakePacket()
handshake.protocol_version = self.context.protocol_version
handshake.server_address = self.options.address
handshake.server_port = self.options.port
handshake.next_state = next_state
self.write_packet(handshake)
def _handle_exception(self, exc, exc_info):
try:
exc.exc_info = exc_info # For backward compatibility.
except (TypeError, AttributeError):
pass
if self.reactor.handle_exception(exc, exc_info):
return
self.exception, self.exc_info = exc, exc_info
if self.handle_exception is None:
raise_(*exc_info)
elif self.handle_exception is not False:
self.handle_exception(exc, exc_info)
def _react(self, packet):
self.reactor.react(packet)
class NetworkingThread(threading.Thread):
def __init__(self, connection, previous=None):
threading.Thread.__init__(self)
self.interrupt = False
self.connection = connection
self.name = "Networking Thread"
self.daemon = True
self.previous_thread = previous
def run(self):
try:
self._run()
except BaseException as e:
self.connection._handle_exception(e, sys.exc_info())
finally:
self.connection.networking_thread = None
def _run(self):
if self.previous_thread is not None:
if self.previous_thread.is_alive():
self.previous_thread.join()
self.previous_thread = None
self.connection.networking_thread = self
while not self.interrupt:
# Attempt to write out as many as 300 packets as possible every
# 0.05 seconds (20 ticks per second)
num_packets = 0
self.connection._write_lock.acquire()
try:
while self.connection._pop_packet():
num_packets += 1
if num_packets >= 300:
break
exc_info = None
except:
exc_info = sys.exc_info()
self.connection._write_lock.release()
# Read and react to as many as 50 packets
num_packets = 0
while num_packets < 50 and not self.interrupt:
packet = self.connection.reactor.read_packet(
self.connection.file_object)
if not packet:
break
num_packets += 1
# Do not raise an IOError if it occurred while a disconnect
# packet was received, as this may be part of an orderly
# disconnection.
if packet.packet_name == 'disconnect' and \
exc_info is not None and isinstance(exc_info[1], IOError):
exc_info = None
try:
self.connection._react(packet)
for listener in self.connection.packet_listeners:
listener.call_packet(packet)
except IgnorePacket:
pass
if exc_info is not None:
raise_(*exc_info)
time.sleep(0.05)
class IgnorePacket(Exception):
"""
This exception may be raised from within a packet handler, such as
`PacketReactor.react' or a packet listener added with
`Connection.register_packet_listener', to stop any subsequent handlers from
being called on that particular packet.
"""
pass
class PacketReactor(object):
"""
Reads and reacts to packets
"""
state_name = None
TIME_OUT = 0
get_clientbound_packets = staticmethod(lambda context: set())
def __init__(self, connection):
self.connection = connection
context = self.connection.context
self.clientbound_packets = {
packet.get_id(context): packet
for packet in self.__class__.get_clientbound_packets(context)}
def read_packet(self, stream):
ready_to_read = select.select([stream], [], [], self.TIME_OUT)[0]
if ready_to_read:
length = VarInt.read(stream)
packet_data = packets.PacketBuffer()
packet_data.send(stream.read(length))
# Ensure we read all the packet
while len(packet_data.get_writable()) < length:
packet_data.send(
stream.read(length - len(packet_data.get_writable())))
packet_data.reset_cursor()
if self.connection.options.compression_enabled:
decompressed_size = VarInt.read(packet_data)
if decompressed_size > 0:
decompressed_packet = decompress(packet_data.read())
assert len(decompressed_packet) == decompressed_size, \
'decompressed length %d, but expected %d' % \
(len(decompressed_packet), decompressed_size)
packet_data.reset()
packet_data.send(decompressed_packet)
packet_data.reset_cursor()
packet_id = VarInt.read(packet_data)
# If we know the structure of the packet, attempt to parse it
# otherwise just skip it
if packet_id in self.clientbound_packets:
packet = self.clientbound_packets[packet_id]()
packet.context = self.connection.context
packet.read(packet_data)
return packet
else:
return packets.Packet(context=self.connection.context)
else:
return None
def react(self, packet):
raise NotImplementedError("Call to base reactor")
""" Called when an exception is raised in the networking thread. If this
method returns True, the default action will be prevented and the
exception ignored (but the networking thread will still terminate).
"""
def handle_exception(self, exc, exc_info):
return False
class LoginReactor(PacketReactor):
get_clientbound_packets = staticmethod(packets.state_login_clientbound)
def react(self, packet):
if packet.packet_name == "encryption request":
secret = encryption.generate_shared_secret()
token, encrypted_secret = encryption.encrypt_token_and_secret(
packet.public_key, packet.verify_token, secret)
# A server id of '-' means the server is in offline mode
if packet.server_id != '-':
server_id = encryption.generate_verification_hash(
packet.server_id, secret, packet.public_key)
if self.connection.auth_token is not None:
self.connection.auth_token.join(server_id)
encryption_response = packets.EncryptionResponsePacket()
encryption_response.shared_secret = encrypted_secret
encryption_response.verify_token = token
# Forced because we'll have encrypted the connection by the time
# it reaches the outgoing queue
self.connection.write_packet(encryption_response, force=True)
# Enable the encryption
cipher = encryption.create_AES_cipher(secret)
encryptor = cipher.encryptor()
decryptor = cipher.decryptor()
self.connection.socket = encryption.EncryptedSocketWrapper(
self.connection.socket, encryptor, decryptor)
self.connection.file_object = \
encryption.EncryptedFileObjectWrapper(
self.connection.file_object, decryptor)
if packet.packet_name == "disconnect":
self.connection.disconnect()
if packet.packet_name == "login success":
self.connection.reactor = PlayingReactor(self.connection)
if packet.packet_name == "set compression":
self.connection.options.compression_threshold = packet.threshold
self.connection.options.compression_enabled = True
class PlayingReactor(PacketReactor):
get_clientbound_packets = staticmethod(packets.state_playing_clientbound)
def react(self, packet):
if packet.packet_name == "set compression":
self.connection.options.compression_threshold = packet.threshold
self.connection.options.compression_enabled = True
if packet.packet_name == "keep alive":
keep_alive_packet = packets.KeepAlivePacketServerbound()
keep_alive_packet.keep_alive_id = packet.keep_alive_id
self.connection.write_packet(keep_alive_packet)
if packet.packet_name == "player position and look":
if self.connection.context.protocol_version >= 107:
teleport_confirm = packets.TeleportConfirmPacket()
teleport_confirm.teleport_id = packet.teleport_id
self.connection.write_packet(teleport_confirm)
else:
position_response = packets.PositionAndLookPacket()
position_response.x = packet.x
position_response.feet_y = packet.y
position_response.z = packet.z
position_response.yaw = packet.yaw
position_response.pitch = packet.pitch
position_response.on_ground = True
self.connection.write_packet(position_response)
self.connection.spawned = True
if packet.packet_name == "disconnect":
self.connection.disconnect()
class StatusReactor(PacketReactor):
get_clientbound_packets = staticmethod(packets.state_status_clientbound)
def __init__(self, connection, do_ping=False):
super(StatusReactor, self).__init__(connection)
self.do_ping = do_ping
def react(self, packet):
if packet.packet_name == "response":
status_dict = json.loads(packet.json_response)
if self.do_ping:
ping_packet = packets.PingPacket()
# NOTE: it may be better to depend on the `monotonic' package
# or something similar for more accurate time measurement.
ping_packet.time = int(1000 * timeit.default_timer())
self.connection.write_packet(ping_packet)
else:
self.connection.disconnect()
self.handle_status(status_dict)
elif packet.packet_name == "ping" and self.do_ping:
now = int(1000 * timeit.default_timer())
self.connection.disconnect()
self.handle_ping(now - packet.time)
def handle_status(self, status_dict):
print(status_dict)
def handle_ping(self, latency_ms):
print('Ping: %d ms' % latency_ms)
class PlayingStatusReactor(StatusReactor):
def __init__(self, connection):
super(PlayingStatusReactor, self).__init__(connection, do_ping=False)
def handle_status(self, status):
if status == {}:
# This can occur when we connect to a Mojang server while it is
# still initialising, so it must not cause the client to connect
# with the default version.
raise IOError('Invalid server status.')
elif 'version' not in status or 'protocol' not in status['version']:
return self.handle_failure()
proto = status['version']['protocol']
if proto not in self.connection.allowed_proto_versions:
vstr = ('%d (%s)' % (proto, status['version']['name'])) \
if 'name' in status['version'] else str(proto)
sstr = 'supported, but not allowed for this connection' \
if proto in SUPPORTED_PROTOCOL_VERSIONS else 'not supported'
raise VersionMismatch("Server's protocol version of %s is %s."
% (vstr, sstr))
self.handle_proto_version(proto)
def handle_proto_version(self, proto_version):
self.connection.allowed_proto_versions = {proto_version}
self.connection.connect()
def handle_failure(self):
self.handle_proto_version(self.connection.default_proto_version)
def handle_exception(self, exc, exc_info):
if isinstance(exc, EOFError):
# An exception of this type may indicate that the server does not
# properly support status queries, so we treat it as non-fatal.
self.handle_failure()
return True