I’m working on a Javacard applet, and currently I’m looking into creating a connection from my phone to my sim card. I want to send some data to a specific app on my phone, on demand.

On the smartcard, I open the BIP/TCP server channel on port 12345 as follows:

import static uicc.toolkit.ToolkitConstants.*;
import uicc.toolkit.*;
import javacard.framework.*;

public class NetworkApplet extends Applet implements ToolkitInterface {
    static final short TCP_TX_BUFFER = Byte.MAX_VALUE * 2;
    static final short PORT_SERVER = 12345;
    static final byte IDX_ID_SERVER_CHANNEL = 0;
    byte[] ids;

    @SuppressWarnings("unused")
    public static void install(byte[] bArray, short bOffset, byte bLength) throws SystemException {
        NetworkApplet applet = new NetworkApplet(bArray, bOffset, bLength);
        applet.register();
        applet.setupToolkitRegistry();
    }

    NetworkApplet(byte[] bArray, short bOffset, byte bLength) {
        ids = JCSystem.makeTransientByteArray((short) 2, JCSystem.CLEAR_ON_RESET);
    }

    void setupToolkitRegistry() {
        ToolkitRegistry registry = ToolkitRegistrySystem.getEntry();

        // snip
        registry.setEvent(EVENT_PROFILE_DOWNLOAD);
    }

    @Override
    public void process(APDU apdu) throws ISOException {
        // Unused
    }

    @Override
    public void processToolkit(short event) throws ToolkitException {
        switch (event) {
            case EVENT_PROFILE_DOWNLOAD:
               ids[IDX_ID_SERVER_CHANNEL] = openServerChannel(PORT_SERVER, TCP_TX_BUFFER);
               break;
            // snip
        }
     }

    private static byte openServerChannel(short port, short txCapacity) {
        ProactiveHandler handler = ProactiveHandlerSystem.getTheHandler();
        ProactiveResponseHandler responseHandler = ProactiveResponseHandlerSystem.getTheHandler();

        handler.init(PRO_CMD_OPEN_CHANNEL, (byte) 0, DEV_ID_TERMINAL);
        handler.appendTLV(TAG_BUFFER_SIZE, txCapacity);
        handler.appendTLV(TAG_UICC_TERMINAL_TRANSPORT_LEVEL, QUAL_TCP_SERVER, port);

        if (handler.send() == RES_CMD_PERF) {
            return responseHandler.getChannelIdentifier();
        } else {
            return 0;
        }
    }
}

Now I have a tcp client running on my Android (it also has to work on iPhone). I’ve tried connecting it to port 12345 on: 127.0.0.1, 192.169.0.1, 192.169.0.2 and localuicc, but nothing seems to work. I get that my card is on a different subnet, but how do I reach it?