black-mamba/mods/utcp.py

# based on https://github.com/ethay012/TCP-over-UDP
import random
import socket
import pickle
import threading
import io
import hashlib
import simplecrypto
from struct import Struct
import uuid

DATA_DIVIDE_LENGTH = 8000
PACKET_HEADER_SIZE = 512                            # Pickle service info
DATA_LENGTH = DATA_DIVIDE_LENGTH
SENT_SIZE = PACKET_HEADER_SIZE + DATA_LENGTH + 272  # Encrypted data always 272 bytes bigger
LAST_CONNECTION = -1
FIRST = 0
PACKET_END = b'___+++^^^END^^^+++___'

# need for emulate
AF_INET = None
SOCK_STREAM = None

class Connection:
    SMALLEST_STARTING_SEQ = 0
    HIGHEST_STARTING_SEQ = 4294967295
    def __init__(self, remote, encrypted=False):
        self.peer_addr = remote
        self.ack = 0
        self.seq = Connection.gen_starting_seq_num()
        self.my_key = None
        if encrypted:
            self.my_key = simplecrypto.RsaKeypair()
            self.pubkey = self.my_key.publickey.serialize()
        self.peer_pub = None
        self.recv_lock = threading.Lock()
        self.send_lock = threading.Lock()
        self.packet_buffer = {
            'SYN': [],
            'ACK': [],
            'SYN-ACK': [],
            'DATA': [],
            'FIN-ACK': []
            }
    @staticmethod
    def gen_starting_seq_num():
        return random.randint(Connection.SMALLEST_STARTING_SEQ, Connection.HIGHEST_STARTING_SEQ)
    def seq_inc(self, inc=1):
        self.seq += inc
        return self.seq
    def set_ack(self, ack):
        self.ack = ack
        return ack

class Ack:
    type = 'ACK'
    def __init__(self, id_):
        self.id = id_
class Fin:
    type = 'FIN'
    def __init__(self):
        self.id = uuid.uuid4().bytes
class FinAck:
    type = 'FIN-ACK'
    def __init__(self, id_):
        self.id = id_
class Syn:
    type = 'SYN'
    checksum = None
    def __init__(self):
        self.id = uuid.uuid4().bytes
    def set_pub(self, pubkey):
        self.checksum = TCP.checksum(pubkey)
        self.pubkey = pubkey
class SynAck:
    type = 'SYN-ACK'
    checksum = None
    def __init__(self, id_):
        self.id = id_
    def set_pub(self, pubkey):
        self.checksum = TCP.checksum(pubkey)
        self.pubkey = pubkey

class Packet:
    def __init__(self):
        self.id = uuid.uuid4().bytes
        self.flag_ack = 0
        self.flag_syn = 0
        self.flag_fin = 0
        self.checksum = 0
        self.data = b''
    def __repr__(self):
        return f'TCPpacket(type={self.packet_type()})'

    def __str__(self):
        return 'UUID: %d, DATA:%s' % (uuid.UUID(bytes=self.id), self.data)

    def set_data(self, data):
        self.checksum = TCP.checksum(data)
        self.data = data



class RestrictedUnpickler(pickle.Unpickler):
    def find_class(self, module, name):
        if module != 'builtins':
            if name == 'Packet': return Packet
            if name == 'Ack': return Ack
            if name == 'Fin': return Fin
            if name == 'FinAck': return FinAck
            if name == 'Syn': return Syn
            if name == 'SynAck': return SynAck
        raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
                                     (module, name))
def restricted_pickle_loads(s):
    return RestrictedUnpickler(io.BytesIO(s)).load()

class UTCPChannel:
    HEADER = Struct('!I')
    TERMINATOR = b'\n'
    POLL_TIMEOUT = 0.1
    def __init__(self, sock):
        self.sock = sock
    def poll(self):
        return self.sock.poll(self.POLL_TIMEOUT)
    def recv(self):
        header = self.sock.recv(self.HEADER.size)
        data_len = self.HEADER.unpack(header)[0]
        terminated_data = self.sock.recv(data_len + len(self.TERMINATOR))
        return terminated_data[:-len(self.TERMINATOR)]
    def send(self, data):
        header = self.HEADER.pack(len(data))
        self.sock.send(header + data + self.TERMINATOR)

class ConnectedSOCK(object):
    def __init__(self, low_sock, client_addr):
        self.client_addr = client_addr
        self.low_sock = low_sock
        self.channel = UTCPChannel(self)
    def __getattribute__(self, att):
        try:
            return object.__getattribute__(self, att)
        except AttributeError:
            return getattr(self.low_sock, att)
    def getpeername(self):
        return self.client_addr
    def send(self, data):
        if self.closed:
            raise EOFError
        return self.low_sock.send(data, self.client_addr)
    def recv(self, size):
        if self.closed:
            raise EOFError
        return self.low_sock.recv(size, self.client_addr)
    @property
    def closed(self):
        return self.low_sock.own_socket._closed or self.client_addr not in self.low_sock.connections
    def close(self):
        if self.client_addr in self.low_sock.connections:
            self.low_sock.close(self.client_addr)
    def shutdown(self, *a, **kw):
        self.close()
    def poll(self, timeout):
        if not self.closed:
            conn = self.low_sock.connections[self.client_addr]
            with conn.recv_lock:
                has_data = self.client_addr in self.packets_received['DATA or FIN']
            if has_data:
                return True
            else:
                self.incoming_packet_event.wait(timeout)
                with conn.recv_lock:
                    return self.client_addr in self.packets_received['DATA or FIN']
        return False

class TCP(object):
    host = None
    port = None
    client = False
    def __init__(self, af_type=None, sock_type=None, encrypted=False):
        self.encrypted = encrypted
        self.incoming_packet_event = threading.Event()
        self.new_conn_event = threading.Event()
        self.own_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.settimeout()
        self.connection_lock = threading.Lock()
        self.queue_lock = threading.Lock()
        self.channel = None
        self.connections = {}
        self.connection_queue = []
        self.packets_received = {'SYN': {}, 'ACK': {}, 'SYN-ACK': {}, 'DATA or FIN': {}, 'FIN-ACK': {}}
    def poll(self, timeout):
        if len(self.connections):
            connection = list(self.connections.keys())[0]
            conn = self.connections[connection]
            with conn.recv_lock:
                has_data = connection in self.packets_received['DATA or FIN']
            if has_data:
                return True
            else:
                self.incoming_packet_event.wait(timeout)
                with conn.recv_lock:
                    return connection in self.packets_received['DATA or FIN']
        return False
    def get_free_port(self):
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.bind(('', 0))
        port = s.getsockname()[1]
        s.close()
        return port
    def setsockopt(self, *a, **kw):
        pass
    def settimeout(self, timeout=5):
        self.own_socket.settimeout(timeout)
    def setblocking(self, mode):
        self.own_socket.setblocking(mode)
    def __repr__(self):
        return 'TCP()'

    def __str__(self):
        return 'Connections: %s' \
               % str(self.connections)
    def getsockname(self):
        return self.own_socket.getsockname()
    def getpeername(self):
        if len(self.connections):
            return list(self.connections.keys())[0]
        else:
            raise EOFError('Not connected')
    def bind(self, addr):
        self.host = addr[0]
        self.port = addr[1]
        self.own_socket.bind(addr)
    def send(self, data, connection=None):
        try:
            if connection not in list(self.connections.keys()):
                if connection is None:
                    connection = list(self.connections.keys())[0]
                else:
                    raise EOFError('Connection not in connected devices')
            conn = self.connections[connection]
            data_parts = TCP.data_divider(data)
            for data_part in data_parts:
                data_chunk = data_part if not self.encrypted else conn.peer_pub.encrypt_raw(data_part)
                packet = Packet()
                packet.set_data(data_chunk)
                packet_to_send = pickle.dumps(packet)
                answer = self.retransmit(connection, packet_to_send, want_id=packet.id)
            return len(data)
        except socket.error as error:
            raise EOFError('Socket was closed before executing command. Error is: %s.' % error)
    def retransmit(self, peer_addr, pickled_packet, condition='ACK', want_id=None):
        data_not_received = True
        retransmit_count = 0
        while data_not_received and retransmit_count < 3:
            data_not_received = False
            try:
                self.own_socket.sendto(pickled_packet, peer_addr)
                answer = self.find_correct_packet(condition, peer_addr, want_id=want_id)
                if not answer:
                    data_not_received = True
                    retransmit_count += 1
            except socket.timeout:
                data_not_received = True
        if not answer:
            self.drop_connection(peer_addr)
            raise EOFError('Connection lost')
        return answer
    def recv(self, size, connection=None):
        try:
            if connection not in list(self.connections.keys()):
                if connection is None:
                    connection = list(self.connections.keys())[0]
                else:
                    raise EOFError('Connection not in connected devices')

            data = self.find_correct_packet('DATA or FIN', connection, size)
            if not self.status:
                raise EOFError('Disconnecting')
            return data
        except socket.error as error:
            raise EOFError('Socket was closed before executing command. Error is: %s.' % error)
    def send_ack(self, connection, ack):
        packet_to_send = pickle.dumps(ack)
        self.own_socket.sendto(packet_to_send, connection)
    def listen_handler(self, max_connections):
        try:
            while True and self.status:
                try:
                    answer, address = self.find_correct_packet('SYN')
                    with self.queue_lock:
                        if len(self.connection_queue) < max_connections:
                            conn = Connection(address, self.encrypted)
                            if self.encrypted:
                                try:
                                    conn.peer_pub = simplecrypto.RsaPublicKey(answer.pubkey)
                                except:
                                    raise socket.error('Init peer public key error')
                            self.connection_queue.append((answer, conn))
                            self.blink_new_conn_event()
                        else:
                            self.own_socket.sendto('Connections full', address)
                except KeyError:
                    continue
        except socket.error as error:
            raise EOFError('Something went wrong in listen_handler func! Error is: %s.' + str(error))

    def listen(self, max_connections=1):
        self.status = 1
        self.central_receive()
        try:
            t = threading.Thread(target=self.listen_handler, args=(max_connections,))
            t.daemon = True
            t.start()
        except Exception as error:
            raise EOFError('Something went wrong in listen func! Error is: %s.' % str(error))

    def accept(self):
        try:
            while True:
                self.new_conn_event.wait(0.1)
                if self.connection_queue:
                    with self.queue_lock:
                        answer, conn = self.connection_queue.pop()
                    self.connections[conn.peer_addr] = conn
                    syn_ack = SynAck(answer.id)
                    if self.encrypted:
                        syn_ack.set_pub(conn.peer_pub.encrypt_raw(conn.pubkey))
                    packet_to_send = pickle.dumps(syn_ack)
                    self.retransmit(conn.peer_addr, packet_to_send, 'ACK', want_id=syn_ack.id)
                    return ConnectedSOCK(self, conn.peer_addr), conn.peer_addr
        except Exception as error:
            self.close(conn.peer_addr)
            raise EOFError('Something went wrong in accept func: ' + str(error))

    def connect(self, server_address=('127.0.0.1', 10000)):
        try:
            self.bind(('', self.get_free_port()))
            self.status = 1
            self.client = True
            self.central_receive()
            conn = Connection(server_address, self.encrypted)
            self.connections[server_address] = conn
            syn = Syn()
            if self.encrypted:
                syn.set_pub(conn.pubkey)
            first_packet_to_send = pickle.dumps(syn)
            try:
                answer = self.retransmit(server_address, first_packet_to_send, 'SYN-ACK', want_id=syn.id)
            except EOFError:
                raise EOFError('Remote peer unreachable')
            if type(answer) == str:  # == 'Connections full':
                raise socket.error('Server cant receive any connections right now.')
            if self.encrypted:
                try:
                    peer_pub = conn.my_key.decrypt_raw(answer.pubkey)
                    conn.peer_pub = simplecrypto.RsaPublicKey(peer_pub)
                except:
                    raise socket.error('Decrypt peer public key error')
            ack = Ack(answer.id)
            second_packet_to_send = pickle.dumps(ack)
            self.own_socket.sendto(second_packet_to_send, server_address)
            self.channel = UTCPChannel(self)
        except socket.error as error:
            self.own_socket.close()
            self.connections = {}
            self.status = 0
            raise EOFError('The socket was closed. Error:' + str(error))
    def fileno(self):
        return self.own_socket.fileno()
    @property
    def closed(self):
        return self.own_socket._closed
    def drop_connection(self, connection):
        with self.connection_lock:
            if len(self.connections):
                self.connections.pop(connection)
            for k in list(self.packets_received.keys()):
                self.packets_received[k].pop(connection)
    def close(self, connection=None):
        try:
            if connection not in list(self.connections.keys()):
                if connection is None:
                    connection = list(self.connections.keys())[0]
                else:
                    raise EOFError('Connection not in connected devices')
            fin = Fin()
            packet_to_send = pickle.dumps(fin)
            self.own_socket.sendto(packet_to_send, connection)
            answer = self.retransmit(connection, packet_to_send, want_id=fin.id)
            answer = self.find_correct_packet('FIN-ACK', connection, want_id=fin.id)
            if not answer:
                raise Exception('The receiver didn\'t send the fin packet')
            else:
                ack = Ack(fin.id)
                self.send_ack(connection, ack)
                self.drop_connection(connection)
                if len(self.connections) == 0 and self.client:
                    self.own_socket.close()
                    self.status = 0
        except Exception as error:
            raise EOFError('Something went wrong in the close func! Error is: %s.' % error)
            
    def disconnect(self, connection, fin_id):
        try:
            ack = Ack(fin_id)
            self.send_ack(connection, ack)
            fin_ack = FinAck(fin_id)
            packet_to_send = pickle.dumps(fin_ack)
            try:
                answer = self.retransmit(connection, packet_to_send, want_id=fin_id)
            except:
                pass
            with self.connection_lock:
                self.connections.pop(connection)
        except Exception as error:
            raise EOFError('Something went wrong in disconnect func:%s ' % error)

    @staticmethod
    def data_divider(data):
        '''Divides the data into a list where each element's length is 1024'''
        data = [data[i:i + DATA_DIVIDE_LENGTH] for i in range(0, len(data), DATA_DIVIDE_LENGTH)]
        data.append(PACKET_END)
        return data

    @staticmethod
    def checksum(source_bytes):
        return hashlib.sha1(source_bytes).digest()

    def find_correct_packet(self, condition, address=('Any',), size=DATA_LENGTH, want_id=None):
        not_found = True
        tries = 0
        while not_found and tries < 2 and self.status:
            try:
                not_found = False
                if address[0] == 'Any':
                    order = self.packets_received[condition].popitem()  # to reverse the tuple received
                    return order[1], order[0]
                conn = self.connections[address]
                if condition in ['ACK', 'SYN-ACK', 'FIN-ACK']:
                    tries += 1
                if condition == 'DATA or FIN':
                    with conn.recv_lock:
                        packet = self.packets_received[condition][address][:size]
                        self.packets_received[condition][address] = self.packets_received[condition][address][size:]
                        if not len(self.packets_received[condition][address]):
                            del self.packets_received[condition][address]
                else:
                    with conn.recv_lock:
                        packet = self.packets_received[condition].pop(address)
                    if want_id and packet.id != want_id:
                        raise KeyError
                return packet
            except KeyError:
                not_found = True
                self.incoming_packet_event.wait(0.1)
    def blink_incoming_packet_event(self):
        self.incoming_packet_event.set()
        self.incoming_packet_event.clear()
    def blink_new_conn_event(self):
        self.new_conn_event.set()
        self.new_conn_event.clear()
    def sort_answers(self, packet, address):
        if address not in self.connections and not isinstance(packet, Syn):
            return
        if isinstance(packet, Syn):
            with self.queue_lock:
                pass
        if isinstance(packet, Fin):
            self.disconnect(address, packet.id)
        elif isinstance(packet, Packet):
            if packet.checksum == TCP.checksum(packet.data):
                conn = self.connections[address]
                data_chunk = packet.data if not self.encrypted else conn.my_key.decrypt_raw(packet.data)
                if data_chunk != PACKET_END:
                    with conn.recv_lock:
                        if address not in self.packets_received['DATA or FIN']:
                            self.packets_received['DATA or FIN'][address] = b''
                        self.packets_received['DATA or FIN'][address] += data_chunk
                ack = Ack(packet.id)
                self.send_ack(address, ack)
            self.blink_incoming_packet_event()
        else:
            if address in self.packets_received[packet.type]:
                conn = self.connections[address]
                with conn.recv_lock:
                    if packet.id == self.packets_received[packet.type][address].id:
                        return
            self.packets_received[packet.type][address] = packet
            self.blink_incoming_packet_event()

    def central_receive_handler(self):
        while True and self.status:
            try:
                packet, address = self.own_socket.recvfrom(SENT_SIZE)
                packet = restricted_pickle_loads(packet)
                self.sort_answers(packet, address)
            except pickle.UnpicklingError:
                continue
            except socket.timeout:
                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()