491 lines
19 KiB
Python
491 lines
19 KiB
Python
# based on https://github.com/ethay012/TCP-over-UDP
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import random
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import socket
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import pickle
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import threading
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import io
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import hashlib
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import simplecrypto
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from struct import Struct
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import uuid
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DATA_DIVIDE_LENGTH = 8000
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PACKET_HEADER_SIZE = 512 # Pickle service info
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DATA_LENGTH = DATA_DIVIDE_LENGTH
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SENT_SIZE = PACKET_HEADER_SIZE + DATA_LENGTH + 272 # Encrypted data always 272 bytes bigger
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LAST_CONNECTION = -1
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FIRST = 0
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PACKET_END = b'___+++^^^END^^^+++___'
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# need for emulate
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AF_INET = None
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SOCK_STREAM = None
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class Connection:
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SMALLEST_STARTING_SEQ = 0
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HIGHEST_STARTING_SEQ = 4294967295
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def __init__(self, remote, encrypted=False):
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self.peer_addr = remote
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self.ack = 0
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self.seq = Connection.gen_starting_seq_num()
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self.my_key = None
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if encrypted:
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self.my_key = simplecrypto.RsaKeypair()
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self.pubkey = self.my_key.publickey.serialize()
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self.peer_pub = None
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self.recv_lock = threading.Lock()
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self.send_lock = threading.Lock()
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@staticmethod
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def gen_starting_seq_num():
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return random.randint(Connection.SMALLEST_STARTING_SEQ, Connection.HIGHEST_STARTING_SEQ)
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def seq_inc(self, inc=1):
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self.seq += inc
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return self.seq
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def set_ack(self, ack):
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self.ack = ack
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return ack
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class Ack:
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def __init__(self, id_):
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self.id = id_
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class Fin:
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def __init__(self):
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self.id = uuid.uuid4().bytes
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class FinAck:
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def __init__(self, id_):
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self.id = id_
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class Syn:
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checksum = None
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def __init__(self):
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self.id = uuid.uuid4().bytes
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def set_pub(self, pubkey):
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self.checksum = TCP.checksum(pubkey)
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self.pubkey = pubkey
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class SynAck:
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checksum = None
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def __init__(self, id_):
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self.id = id_
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def set_pub(self, pubkey):
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self.checksum = TCP.checksum(pubkey)
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self.pubkey = pubkey
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class Packet:
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def __init__(self):
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self.id = uuid.uuid4().bytes
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self.flag_ack = 0
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self.flag_syn = 0
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self.flag_fin = 0
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self.checksum = 0
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self.data = b''
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def __repr__(self):
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return f'TCPpacket(type={self.packet_type()})'
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def __str__(self):
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return 'UUID: %d, DATA:%s' % (uuid.UUID(bytes=self.id), self.data)
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def set_data(self, data):
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self.checksum = TCP.checksum(data)
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self.data = data
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class RestrictedUnpickler(pickle.Unpickler):
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def find_class(self, module, name):
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if module != 'builtins':
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if name == 'Packet': return Packet
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if name == 'Ack': return Ack
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if name == 'Fin': return Fin
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if name == 'FinAck': return FinAck
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if name == 'Syn': return Syn
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if name == 'SynAck': return SynAck
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raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
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(module, name))
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def restricted_pickle_loads(s):
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return RestrictedUnpickler(io.BytesIO(s)).load()
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class UTCPChannel:
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HEADER = Struct('!I')
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TERMINATOR = b'\n'
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POLL_TIMEOUT = 0.1
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def __init__(self, sock):
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self.sock = sock
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def poll(self):
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return self.sock.poll(self.POLL_TIMEOUT)
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def recv(self):
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header = self.sock.recv(self.HEADER.size)
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data_len = self.HEADER.unpack(header)[0]
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terminated_data = self.sock.recv(data_len + len(self.TERMINATOR))
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return terminated_data[:-len(self.TERMINATOR)]
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def send(self, data):
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header = self.HEADER.pack(len(data))
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self.sock.send(header + data + self.TERMINATOR)
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class ConnectedSOCK(object):
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def __init__(self, low_sock, client_addr):
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self.client_addr = client_addr
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self.low_sock = low_sock
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self.channel = UTCPChannel(self)
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def __getattribute__(self, att):
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try:
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return object.__getattribute__(self, att)
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except AttributeError:
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return getattr(self.low_sock, att)
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def getpeername(self):
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return self.client_addr
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def send(self, data):
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if self.closed:
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raise EOFError
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return self.low_sock.send(data, self.client_addr)
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def recv(self, size):
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if self.closed:
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raise EOFError
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return self.low_sock.recv(size, self.client_addr)
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@property
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def closed(self):
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return self.low_sock.own_socket._closed or self.client_addr not in self.low_sock.connections
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def close(self):
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if self.client_addr in self.low_sock.connections:
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self.low_sock.close(self.client_addr)
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def shutdown(self, *a, **kw):
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self.close()
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def poll(self, timeout):
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if not self.closed:
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conn = self.low_sock.connections[self.client_addr]
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with conn.recv_lock:
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has_data = self.client_addr in self.packets_received['DATA or FIN']
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if has_data:
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return True
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else:
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self.incoming_packet_event.wait(timeout)
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with conn.recv_lock:
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return self.client_addr in self.packets_received['DATA or FIN']
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return False
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class TCP(object):
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host = None
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port = None
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client = False
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def __init__(self, af_type=None, sock_type=None, encrypted=False):
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self.encrypted = encrypted
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self.incoming_packet_event = threading.Event()
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self.new_conn_event = threading.Event()
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self.own_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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self.settimeout()
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self.connection_lock = threading.Lock()
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self.queue_lock = threading.Lock()
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self.channel = None
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self.connections = {}
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self.connection_queue = []
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self.packets_received = {'SYN': {}, 'ACK': {}, 'SYN-ACK': {}, 'DATA or FIN': {}, 'FIN-ACK': {}}
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def poll(self, timeout):
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if len(self.connections):
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connection = list(self.connections.keys())[0]
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conn = self.connections[connection]
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with conn.recv_lock:
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has_data = connection in self.packets_received['DATA or FIN']
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if has_data:
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return True
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else:
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self.incoming_packet_event.wait(timeout)
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with conn.recv_lock:
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return connection in self.packets_received['DATA or FIN']
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return False
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def get_free_port(self):
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s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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s.bind(('', 0))
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port = s.getsockname()[1]
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s.close()
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return port
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def setsockopt(self, *a, **kw):
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pass
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def settimeout(self, timeout=5):
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self.own_socket.settimeout(timeout)
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def setblocking(self, mode):
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self.own_socket.setblocking(mode)
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def __repr__(self):
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return 'TCP()'
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def __str__(self):
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return 'Connections: %s' \
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% str(self.connections)
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def getsockname(self):
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return self.own_socket.getsockname()
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def getpeername(self):
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if len(self.connections):
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return list(self.connections.keys())[0]
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else:
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raise EOFError('Not connected')
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def bind(self, addr):
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self.host = addr[0]
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self.port = addr[1]
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self.own_socket.bind(addr)
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def send(self, data, connection=None):
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try:
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if connection not in list(self.connections.keys()):
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if connection is None:
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connection = list(self.connections.keys())[0]
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else:
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raise EOFError('Connection not in connected devices')
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conn = self.connections[connection]
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data_parts = TCP.data_divider(data)
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for data_part in data_parts:
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data_chunk = data_part if not self.encrypted else conn.peer_pub.encrypt_raw(data_part)
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packet = Packet()
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packet.set_data(data_chunk)
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packet_to_send = pickle.dumps(packet)
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answer = self.retransmit(connection, packet_to_send, wnat_id=packet.id)
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return len(data)
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except socket.error as error:
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raise EOFError('Socket was closed before executing command. Error is: %s.' % error)
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def retransmit(self, peer_addr, pickled_packet, condition='ACK', want_id=None):
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data_not_received = True
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retransmit_count = 0
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while data_not_received and retransmit_count < 3:
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data_not_received = False
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try:
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self.own_socket.sendto(pickled_packet, peer_addr)
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answer = self.find_correct_packet(condition, peer_addr, want_id=want_id)
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if not answer:
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data_not_received = True
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retransmit_count += 1
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except socket.timeout:
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data_not_received = True
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if not answer:
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self.drop_connection(peer_addr)
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raise EOFError('Connection lost')
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return answer
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def recv(self, size, connection=None):
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try:
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if connection not in list(self.connections.keys()):
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if connection is None:
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connection = list(self.connections.keys())[0]
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else:
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raise EOFError('Connection not in connected devices')
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data = self.find_correct_packet('DATA or FIN', connection, size)
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if not self.status:
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raise EOFError('Disconnecting')
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return data
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except socket.error as error:
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raise EOFError('Socket was closed before executing command. Error is: %s.' % error)
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def send_ack(self, connection, ack):
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packet_to_send = pickle.dumps(ack)
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self.own_socket.sendto(packet_to_send, connection)
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def listen_handler(self, max_connections):
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try:
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while True and self.status:
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try:
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answer, address = self.find_correct_packet('SYN')
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with self.queue_lock:
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if len(self.connection_queue) < max_connections:
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conn = Connection(address, self.encrypted)
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if self.encrypted:
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try:
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conn.peer_pub = simplecrypto.RsaPublicKey(answer.data)
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except:
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raise socket.error('Init peer public key error')
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self.connection_queue.append((answer, conn))
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self.blink_new_conn_event()
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else:
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self.own_socket.sendto('Connections full', address)
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except KeyError:
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continue
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except socket.error as error:
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raise EOFError('Something went wrong in listen_handler func! Error is: %s.' + str(error))
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def listen(self, max_connections=1):
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self.status = 1
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self.central_receive()
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try:
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t = threading.Thread(target=self.listen_handler, args=(max_connections,))
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t.daemon = True
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t.start()
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except Exception as error:
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raise EOFError('Something went wrong in listen func! Error is: %s.' % str(error))
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def accept(self):
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try:
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while True:
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self.new_conn_event.wait(0.1)
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if self.connection_queue:
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with self.queue_lock:
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answer, conn = self.connection_queue.pop()
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self.connections[conn.peer_addr] = conn
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syn_ack = SynAck(answer.id)
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if self.encrypted:
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syn_ack.set_pub(conn.peer_pub.encrypt_raw(conn.pubkey))
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packet_to_send = pickle.dumps(syn_ack)
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self.retransmit(conn.peer_addr, packet_to_send, 'ACK', want_id=syn_ack.id)
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return ConnectedSOCK(self, conn.peer_addr), conn.peer_addr
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except Exception as error:
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self.close(conn.peer_addr)
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raise EOFError('Something went wrong in accept func: ' + str(error))
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def connect(self, server_address=('127.0.0.1', 10000)):
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try:
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self.bind(('', self.get_free_port()))
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self.status = 1
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self.client = True
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self.central_receive()
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conn = Connection(server_address, self.encrypted)
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self.connections[server_address] = conn
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syn = Syn()
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if self.encrypted:
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syn.set_pub(conn.pubkey)
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first_packet_to_send = pickle.dumps(syn)
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try:
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answer = self.retransmit(server_address, first_packet_to_send, 'SYN-ACK', want_id=syn.id)
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except EOFError:
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raise EOFError('Remote peer unreachable')
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if type(answer) == str: # == 'Connections full':
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raise socket.error('Server cant receive any connections right now.')
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if self.encrypted:
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try:
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peer_pub = conn.my_key.decrypt_raw(answer.data)
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conn.peer_pub = simplecrypto.RsaPublicKey(peer_pub)
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except:
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raise socket.error('Decrypt peer public key error')
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ack = Ack(answer.id)
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second_packet_to_send = pickle.dumps(ack)
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self.own_socket.sendto(second_packet_to_send, server_address)
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self.channel = UTCPChannel(self)
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except socket.error as error:
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self.own_socket.close()
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self.connections = {}
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self.status = 0
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raise EOFError('The socket was closed. Error:' + str(error))
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def fileno(self):
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return self.own_socket.fileno()
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@property
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def closed(self):
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return self.own_socket._closed
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def drop_connection(self, connection):
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with self.connection_lock:
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if len(self.connections):
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self.connections.pop(connection)
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def close(self, connection=None):
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try:
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if connection not in list(self.connections.keys()):
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if connection is None:
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connection = list(self.connections.keys())[0]
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else:
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raise EOFError('Connection not in connected devices')
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fin = Fin()
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packet_to_send = pickle.dumps(fin)
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self.own_socket.sendto(packet_to_send, connection)
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answer = self.retransmit(connection, packet_to_send, want_id=fin.id)
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answer = self.find_correct_packet('FIN-ACK', connection, want_id=fin.id)
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if not answer:
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raise Exception('The receiver didn\'t send the fin packet')
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else:
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ack = Ack(fin.id)
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self.send_ack(connection, ack)
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self.drop_connection(connection)
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if len(self.connections) == 0 and self.client:
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self.own_socket.close()
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self.status = 0
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except Exception as error:
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raise EOFError('Something went wrong in the close func! Error is: %s.' % error)
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def disconnect(self, connection, fin_id):
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try:
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ack = Ack(fin_id)
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self.send_ack(connection, ack)
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fin_ack = FinAck(fin_id)
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packet_to_send = pickle.dumps(fin_ack)
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try:
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answer = self.retransmit(connection, packet_to_send, want_id=fin_id)
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except:
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pass
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with self.connection_lock:
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self.connections.pop(connection)
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except Exception as error:
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raise EOFError('Something went wrong in disconnect func:%s ' % error)
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@staticmethod
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def data_divider(data):
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'''Divides the data into a list where each element's length is 1024'''
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data = [data[i:i + DATA_DIVIDE_LENGTH] for i in range(0, len(data), DATA_DIVIDE_LENGTH)]
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data.append(PACKET_END)
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return data
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@staticmethod
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def checksum(source_bytes):
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return hashlib.sha1(source_bytes).digest()
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def find_correct_packet(self, condition, address=('Any',), size=DATA_LENGTH, want_id=None):
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not_found = True
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tries = 0
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while not_found and tries < 2 and self.status:
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try:
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not_found = False
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if address[0] == 'Any':
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order = self.packets_received[condition].popitem() # to reverse the tuple received
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return order[1], order[0]
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conn = self.connections[address]
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if condition in ['ACK', 'SYN-ACK', 'FIN-ACK']:
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tries += 1
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if condition == 'DATA or FIN':
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with conn.recv_lock:
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packet = self.packets_received[condition][address][:size]
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self.packets_received[condition][address] = self.packets_received[condition][address][size:]
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if not len(self.packets_received[condition][address]):
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del self.packets_received[condition][address]
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else:
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packet = self.packets_received[condition].pop(address)
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if want_id and packet.id != want_id:
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raise KeyError
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return packet
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except KeyError:
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not_found = True
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self.incoming_packet_event.wait(0.1)
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def blink_incoming_packet_event(self):
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self.incoming_packet_event.set()
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self.incoming_packet_event.clear()
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def blink_new_conn_event(self):
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self.new_conn_event.set()
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self.new_conn_event.clear()
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def sort_answers(self, packet, address):
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if address not in self.connections and not isinstance(packet, Syn):
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return
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if isinstance(packet, Fin):
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self.disconnect(address, packet.id)
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elif isinstance(packet, Packet):
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if packet.checksum == TCP.checksum(packet.data):
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conn = self.connections[address]
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data_chunk = packet.data if not self.encrypted else conn.my_key.decrypt_raw(packet.data)
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if data_chunk != PACKET_END:
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with conn.recv_lock:
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if address not in self.packets_received['DATA or FIN']:
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self.packets_received['DATA or FIN'][address] = b''
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self.packets_received['DATA or FIN'][address] += data_chunk
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ack = Ack(packet.id)
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self.send_ack(address, ack)
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self.blink_incoming_packet_event()
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elif packet.packet_type() == '':
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#print('redundant packet found', packet)
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pass
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else:
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self.packets_received[packet.packet_type()][address] = packet
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self.blink_incoming_packet_event()
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def central_receive_handler(self):
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while True and self.status:
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try:
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packet, address = self.own_socket.recvfrom(SENT_SIZE)
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packet = restricted_pickle_loads(packet)
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self.sort_answers(packet, address)
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except pickle.UnpicklingError:
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continue
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except socket.timeout:
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continue
|
|
except socket.error as error:
|
|
self.own_socket.close()
|
|
self.status = 0
|
|
# print('An error has occured: Socket error %s' % error)
|
|
|
|
def central_receive(self):
|
|
t = threading.Thread(target=self.central_receive_handler)
|
|
t.daemon = True
|
|
t.start()
|