Initial release

The initial release contains the most basic implementation of TLSharp core.
This is also fully untested, since no test can be done until more work is done.

network/tcp_transport.py

@@ -0,0 +1,52 @@
+from zlib import crc32
+
+from network.tcp_message import TcpMessage
+from network.tcp_client import TcpClient
+
+
+class TcpTransport:
+
+    def __init__(self, ip_address, port):
+        self._tcp_client = TcpClient()
+        self._send_counter = 0
+
+        self._tcp_client.connect(ip_address, port)
+
+    def send(self, packet):
+        """
+        :param packet: Bytes array representing the packet to be sent
+        """
+        if not self._tcp_client.connected:
+            raise ConnectionError('Client not connected to server.')
+
+        tcp_message = TcpMessage(self._send_counter, packet)
+
+        # TODO async? and receive too, of course
+        self._tcp_client.write(tcp_message.encode())
+
+        self._send_counter += 1
+
+    def receive(self):
+        # First read everything
+        packet_length_bytes = self._tcp_client.read(4)
+        packet_length = int.from_bytes(packet_length_bytes, byteorder='big')
+
+        seq_bytes = self._tcp_client.read(4)
+        seq = int.from_bytes(seq_bytes, byteorder='big')
+
+        body = self._tcp_client.read(packet_length - 12)
+
+        checksum = int.from_bytes(self._tcp_client.read(4), byteorder='big')
+
+        # Then perform the checks
+        rv = packet_length_bytes + seq_bytes + body
+        valid_checksum = crc32(rv) & 0xFFFFFFFF  # Ensure it's unsigned (http://stackoverflow.com/a/30092291/4759433)
+
+        if checksum != valid_checksum:
+            raise ValueError('Invalid checksum, skip')
+
+        return TcpMessage(seq, body)
+
+    def dispose(self):
+        if self._tcp_client.connected:
+            self._tcp_client.close()