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

Change-Id: I588bf4b3d9891766dd688a6818057ca20fb26e3f

pySim/transport/__init__.py

@@ -328,11 +328,13 @@ def argparse_add_reader_args(arg_parser: argparse.ArgumentParser):
     from pySim.transport.pcsc import PcscSimLink
     from pySim.transport.modem_atcmd import ModemATCommandLink
     from pySim.transport.calypso import CalypsoSimLink
+    from pySim.transport.wsrc import WsrcSimLink
 
     SerialSimLink.argparse_add_reader_args(arg_parser)
     PcscSimLink.argparse_add_reader_args(arg_parser)
     ModemATCommandLink.argparse_add_reader_args(arg_parser)
     CalypsoSimLink.argparse_add_reader_args(arg_parser)
+    WsrcSimLink.argparse_add_reader_args(arg_parser)
     arg_parser.add_argument('--apdu-trace', action='store_true',
                             help='Trace the command/response APDUs exchanged with the card')
 
@@ -355,6 +357,9 @@ def init_reader(opts, **kwargs) -> LinkBase:
     elif opts.modem_dev is not None:
         from pySim.transport.modem_atcmd import ModemATCommandLink
         sl = ModemATCommandLink(opts, **kwargs)
+    elif opts.wsrc_server_url is not None:
+        from pySim.transport.wsrc import WsrcSimLink
+        sl = WsrcSimLink(opts, **kwargs)
     else:  # Serial reader is default
         print("No reader/driver specified; falling back to default (Serial reader)")
         from pySim.transport.serial import SerialSimLink

pySim/transport/wsrc.py

@@ -0,0 +1,99 @@
+# Copyright (C) 2024  Harald Welte <laforge@gnumonks.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import argparse
+from typing import Optional
+
+from osmocom.utils import h2i, i2h, Hexstr, is_hexstr
+
+from pySim.exceptions import NoCardError, ProtocolError, ReaderError
+from pySim.transport import LinkBase
+from pySim.utils import ResTuple
+from pySim.wsrc import WSRC_DEFAULT_PORT_USER
+from pySim.wsrc.client_blocking import WsClientBlocking
+
+class UserWsClientBlocking(WsClientBlocking):
+    def __init__(self, ws_uri: str, **kwargs):
+        super().__init__('user', ws_uri, **kwargs)
+
+    def select_card(self, id_type:str, id_str:str):
+        rx = self.transceive_json('select_card', {'id_type': id_type, 'id_str': id_str},
+                                  'select_card_ack')
+        return rx
+
+    def reset_card(self):
+        self.transceive_json('reset_req', {}, 'reset_resp')
+
+    def xceive_apdu_raw(self, cmd: Hexstr) -> ResTuple:
+        rx = self.transceive_json('c_apdu', {'command': cmd}, 'r_apdu')
+        return rx['response'], rx['sw']
+
+
+class WsrcSimLink(LinkBase):
+    """ pySim: WSRC (WebSocket Remote Card) reader transport link."""
+    name = 'WSRC'
+
+    def __init__(self, opts: argparse.Namespace, **kwargs):
+        super().__init__(**kwargs)
+        self.identities = {}
+        self.server_url = opts.wsrc_server_url
+        if opts.wsrc_eid:
+            self.id_type = 'eid'
+            self.id_str = opts.wsrc_eid
+        elif opts.wsrc_iccid:
+            self.id_type = 'iccid'
+            self.id_str = opts.wsrc_iccid
+        self.client = UserWsClientBlocking(self.server_url)
+        self.client.connect()
+
+    def __del__(self):
+       # FIXME: disconnect from server
+       pass
+
+    def wait_for_card(self, timeout: Optional[int] = None, newcardonly: bool = False):
+        self.connect()
+
+    def connect(self):
+        rx = self.client.select_card(self.id_type, self.id_str)
+        self.identities = rx['identities']
+
+    def get_atr(self) -> Hexstr:
+        return h2i(self.identities['ATR'])
+
+    def disconnect(self):
+        self.__delete__()
+
+    def _reset_card(self):
+        self.client.reset_card()
+        return 1
+
+    def _send_apdu_raw(self, pdu: Hexstr) -> ResTuple:
+        return self.client.xceive_apdu_raw(pdu)
+
+    def __str__(self) -> str:
+        return "WSRC[%s=%s]" % (self.id_type, self.id_str)
+
+    @staticmethod
+    def argparse_add_reader_args(arg_parser: argparse.ArgumentParser):
+        wsrc_group = arg_parser.add_argument_group('WebSocket Remote Card',
+            """WebSocket Remote Card (WSRC) is a protoocl by which remot cards / card readers
+            can be accessed via a network.""")
+        wsrc_group.add_argument('--wsrc-server-url', default='ws://localhost:%u' % WSRC_DEFAULT_PORT_USER,
+                                help='URI of the WSRC server to connect to')
+        wsrc_group.add_argument('--wsrc-iccid', type=is_hexstr,
+                                help='ICCID of the card to open via WSRC')
+        wsrc_group.add_argument('--wsrc-eid', type=is_hexstr,
+                                help='EID of the card to open via WSRC')

pySim/wsrc/__init__.py

@@ -0,0 +1,3 @@
+
+WSRC_DEFAULT_PORT_USER = 4220
+WSRC_DEFAULT_PORT_CARD = 4221

pySim/wsrc/client_blocking.py

@@ -0,0 +1,68 @@
+"""Connect smartcard to a remote server, so the remote server can take control and
+perform commands on it."""
+
+import abc
+import json
+import logging
+from typing import Optional
+from websockets.sync.client import connect
+from osmocom.utils import b2h
+
+logger = logging.getLogger(__name__)
+
+class WsClientBlocking(abc.ABC):
+    """Generalized synchronous/blocking client for the WSRC (Web Socket Remote Card) protocol"""
+
+    def __init__(self, cltype: str, ws_uri: str):
+        self.client_type = cltype
+        self.ws_uri = ws_uri
+        self.ws = None
+
+    def connect(self):
+        self.ws = connect(uri=self.ws_uri)
+        self.perform_outbound_hello()
+
+    def tx_json(self, msg_type: str, d: dict = {}):
+        """JSON-Encode and transmit a message to the given websocket."""
+        d['msg_type'] = msg_type
+        d_js = json.dumps(d)
+        logger.debug("Tx: %s", d_js)
+        self.ws.send(d_js)
+
+    def tx_error(self, message: str):
+        event = {
+            'message': message,
+        }
+        self.tx_json('error', event)
+
+    def rx_json(self):
+        """Receive a single message from the given websocket and JSON-decode it."""
+        rx = self.ws.recv()
+        rx_js = json.loads(rx)
+        logger.debug("Rx: %s", rx_js)
+        assert 'msg_type' in rx
+        return rx_js
+
+    def transceive_json(self, tx_msg_type: str, tx_d: Optional[dict], rx_msg_type: str) -> dict:
+        self.tx_json(tx_msg_type, tx_d)
+        rx = self.rx_json()
+        assert rx['msg_type'] == rx_msg_type
+        return rx
+
+    def perform_outbound_hello(self, tx: dict = {}):
+        if not 'client_type' in tx:
+            tx['client_type'] = self.client_type
+        self.tx_json('hello', tx)
+        rx = self.rx_json()
+        assert rx['msg_type'] == 'hello_ack'
+        return rx
+
+    def rx_and_execute_cmd(self):
+        """Receve and dispatch/execute a single command from the server."""
+        rx = self.rx_json()
+        handler = getattr(self, 'handle_rx_%s' % rx['msg_type'], None)
+        if handler:
+            handler(rx)
+        else:
+            logger.error('Received unknown/unsupported msg_type %s' % rx['msg_type'])
+            self.tx_error('Message type "%s" is not supported' % rx['msg_type'])