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53 lines
1.8 KiB
Python
Executable File
53 lines
1.8 KiB
Python
Executable File
# This file is based on TLSharp
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# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Network/TcpTransport.cs
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from network import TcpMessage, TcpClient
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from binascii import crc32
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class TcpTransport:
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def __init__(self, ip_address, port):
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self._tcp_client = TcpClient()
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self._send_counter = 0
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self._tcp_client.connect(ip_address, port)
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def send(self, packet):
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"""Sends the given packet (bytes array) to the connected peer"""
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if not self._tcp_client.connected:
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raise ConnectionError('Client not connected to server.')
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# Get a TcpMessage which contains the given packet
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tcp_message = TcpMessage(self._send_counter, packet)
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# TODO In TLSharp, this is async; Should both send and receive be here too?
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self._tcp_client.write(tcp_message.encode())
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self._send_counter += 1
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def receive(self):
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"""Receives a TcpMessage from the connected peer"""
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# First read everything
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packet_length_bytes = self._tcp_client.read(4)
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packet_length = int.from_bytes(packet_length_bytes, byteorder='little')
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seq_bytes = self._tcp_client.read(4)
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seq = int.from_bytes(seq_bytes, byteorder='little')
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body = self._tcp_client.read(packet_length - 12)
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checksum = int.from_bytes(self._tcp_client.read(4), byteorder='little', signed=False)
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# Then perform the checks
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rv = packet_length_bytes + seq_bytes + body
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valid_checksum = crc32(rv)
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if checksum != valid_checksum:
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raise ValueError('Invalid checksum, skip')
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# If we passed the tests, we can then return a valid TcpMessage
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return TcpMessage(seq, body)
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def dispose(self):
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if self._tcp_client.connected:
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self._tcp_client.close()
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