WIP: initial step towards websocket-based remote card [reader] access

Change-Id: I588bf4b3d9891766dd688a6818057ca20fb26e3f

contrib/card2server.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+
+"""Connect smartcard to a remote server, so the remote server can take control and
+perform commands on it."""
+
+import sys
+import json
+import logging
+import argparse
+from osmocom.utils import b2h
+import websockets
+
+from pySim.transport import init_reader, argparse_add_reader_args, LinkBase
+from pySim.commands import SimCardCommands
+from pySim.wsrc.client_blocking import WsClientBlocking
+
+logging.basicConfig(format="[%(levelname)s] %(asctime)s %(message)s", level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+class CardWsClientBlocking(WsClientBlocking):
+    """Implementation of the card (reader) client of the WSRC (WebSocket Remote Card) protocol"""
+
+    def __init__(self, ws_uri, tp: LinkBase):
+        super().__init__(ws_uri)
+        self.tp = tp
+
+    def perform_outbound_hello(self):
+        hello_data = {
+            'client_type': 'card',
+            'atr': b2h(self.tp.get_atr()),
+            # TODO: include various card information in the HELLO message
+        }
+        super().perform_outbound_hello(hello_data)
+
+    def handle_rx_c_apdu(self, rx: dict):
+        """handle an inbound APDU transceive command"""
+        data, sw = self.tp.send_apdu(rx['command'])
+        tx = {
+            'response': data,
+            'sw': sw,
+        }
+        self.tx_json('r_apdu', tx)
+
+    def handle_rx_disconnect(self, rx: dict):
+        """server tells us to disconnect"""
+        self.tx_json('disconnect_ack')
+        # FIXME: tear down connection and/or terminate entire program
+
+    def handle_rx_print(self, rx: dict):
+        """print a message (text) given by server to the local console/log"""
+        print(rx['message'])
+        # no response
+
+    def handle_rx_reset_req(self, rx: dict):
+        """server tells us to reset the card"""
+        self.tp.reset()
+        self.tx_json('reset_resp', {'atr': b2h(self.tp.get_atr())})
+
+
+parser = argparse.ArgumentParser()
+argparse_add_reader_args(parser)
+parser.add_argument("--uri", default="ws://localhost:8765/",
+                    help="URI of the sever to which to connect")
+
+opts = parser.parse_args()
+
+# open the card reader / slot
+logger.info("Initializing Card Reader...")
+tp = init_reader(opts)
+logger.info("Connecting to Card...")
+tp.connect()
+scc = SimCardCommands(transport=tp)
+logger.info("Detected Card with ATR: %s" % b2h(tp.get_atr()))
+
+# TODO: gather various information about the card; print it
+
+# create + connect the client to the server
+cl = CardWsClientBlocking(opts.uri, tp)
+logger.info("Connecting to remote server...")
+try:
+    cl.connect()
+    print("Successfully connected to Server")
+except ConnectionRefusedError as e:
+    print(e)
+    sys.exit(1)
+
+try:
+    while True:
+        # endless loop: wait for inbound command from server + execute it
+        cl.rx_and_execute_cmd()
+        # TODO: clean handling of websocket disconnect
+except websockets.exceptions.ConnectionClosedOK as e:
+    print(e)
+    sys.exit(1)
+except KeyboardInterrupt as e:
+    print(e.__class__.__name__)
+    sys.exit(2)