Linux Bluetooth não encontrando serviço Android com Uuid

Question

Estou tentando escrever um programa em um sistema incorporado executando o GumStix (Linux) para conectar e conversar com um dispositivo Android 2.x sobre o Bluetooth. O Gumstix é o cliente e o Android é o servidor. Estou tentando encontrar o número do canal que meu serviço Android usa para que o Gumstix possa se conectar a ele, mas por algum motivo minha rotina não está retornando um número de canal porque parece não encontrar um serviço com um UUID correspondente.

Suspeito que o UUID fornecido à rotina Gumstix e o UUID no dispositivo Android não sejam realmente o mesmo número. O Android requer um Uuid de 128 bits:

De Documentação do Android:

O UUID é uma representação imutável de um identificador universalmente único de 128 bits (UUID).

Existem vários layouts variantes de UUIDs, mas essa classe é baseada na variante 2 do RFC 4122, a variante Leach-Salz. Essa classe pode ser usada para modelar variantes alternativas, mas a maioria dos métodos não será suportada nesses casos; Veja cada método para

Uuid usado no Android:

public static final String UUID_STRING = "00000000-0000-0000-0000-00000000ABCD";
private static final UUID MY_UUID = UUID.fromString(UUID_STRING);

Código C em Gumstix Procure comentários indicando onde falha

int main(int argc , char **argv)
{
//Android wants a 128 bit UUID why are we only giving a 32 bit UUID
uint32_t svc_uuid_int[] = { 0 , 0 , 0 , 0xABCD } ;

int status ;
bdaddr_t target ;
uuid_t svc_uuid ;
sdp_list_t *response_list , *search_list , *attrid_list ;
sdp_session_t *session = 0;
uint32_t range = 0x0000ffff ;
uint8_t port = 0;

if(argc < 2)
{
    fprintf(stderr , "usage: %s <bt_addr>\n" , argv [ 0 ] ) ;
    exit ( 2 ) ;
}

str2ba ( argv[1] , &target ) ;
// connect to the SDP server running on the remote machine
session = sdp_connect ( BDADDR_ANY, &target, SDP_RETRY_IF_BUSY  );
//  printf("session %u\n",session);

sdp_uuid128_create( &svc_uuid, &svc_uuid_int ) ;
search_list = sdp_list_append( 0, &svc_uuid ) ;
attrid_list = sdp_list_append( 0, &range ) ;

// get a list of service records that have UUID 0xabcd
response_list = NULL ;   //ERROR: response_list SHOULD GET INITIALIZED BUT IT STAYS NULL CAUSING THE PROGRAM TO NEVER ENTER THE FOR LOOP BELOW.
status = sdp_service_search_attr_req(session , search_list , SDP_ATTR_REQ_RANGE , attrid_list, &response_list ) ;
printf("status %d\n",status);

if( status == 0 )
{
    sdp_list_t *proto_list = NULL ;
    sdp_list_t *r = response_list ;
    // go through each of the service records
    for ( ; r ; r = r->next )
    {
        sdp_record_t *rec = (sdp_record_t * ) r->data ;
        // get a list of the protocol sequences
        if( sdp_get_access_protos( rec, &proto_list ) == 0 ) 
        {
            // get the RFCOMM port number
            port = sdp_get_proto_port( proto_list , RFCOMM_UUID ) ;
            sdp_list_free( proto_list, 0 );
        }
        sdp_record_free( rec ) ;
    }
}

sdp_list_free( response_list, 0 );
sdp_list_free( search_list, 0 );
sdp_list_free( attrid_list, 0 );
sdp_close( session ) ;
if( port != 0 )
{
    printf( "found service running on RFCOMM port %d\n" , port ) ;
}
return 0;

}

EDITAR:

Código Android para o AcceptThread (aceita conexões), ConnectThread (completa a conexão) e o ConnectETThread (mantém a conexão, estabelece manipulador)

/**
 * This thread runs while listening for incoming connections. It behaves
 * like a server-side client. It runs until a connection is accepted
 * (or until canceled).
 */
private class AcceptThread extends Thread {
    // The local server socket
    private final BluetoothServerSocket mmServerSocket;

    public AcceptThread() {
        BluetoothServerSocket tmp = null;

        // Create a new listening server socket
        try {
            tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
        } catch (IOException e) {
            Log.e(TAG, "listen() failed", e);
        }
        mmServerSocket = tmp;
    }

    public void run() {
        if (D) Log.d(TAG, "BEGIN mAcceptThread" + this);
        setName("AcceptThread");
        BluetoothSocket socket = null;

        // Listen to the server socket if we're not connected
        while (mState != STATE_CONNECTED) {
            try {
                // This is a blocking call and will only return on a
                // successful connection or an exception
                if(D) Log.i("prism", "Waiting to connect************");
                socket = mmServerSocket.accept();
                if(D) Log.i("prism", "We have accepted connection and are connected***************");
            } catch (IOException e) {
                Log.e(TAG, "accept() failed", e);
                break;
            }

            // If a connection was accepted
            if (socket != null) {
                synchronized (BluetoothServer.this) {
                    switch (mState) {
                    case STATE_LISTEN:
                    case STATE_CONNECTING:
                        // Situation normal. Start the connected thread.
                        connected(socket, socket.getRemoteDevice());
                        break;
                    case STATE_NONE:
                    case STATE_CONNECTED:
                        // Either not ready or already connected. Terminate new socket.
                        try {
                            if (D) Log.i("prism", "Bluetooth already connected, abandoning request from " + socket.getRemoteDevice().getName());
                            socket.close();
                        } catch (IOException e) {
                            Log.e(TAG, "Could not close unwanted socket", e);
                        }
                        break;
                    }
                }
            }
        }
        if (D) Log.i(TAG, "END mAcceptThread");
    }

    public void cancel() {
        if (D) Log.d(TAG, "cancel " + this);
        try {
            mmServerSocket.close();
        } catch (IOException e) {
            Log.e(TAG, "close() of server failed", e);
        }
    }
}

/**
 * This thread runs while attempting to make an outgoing connection
 * with a device. It runs straight through; the connection either
 * succeeds or fails.
 */
private class ConnectThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final BluetoothDevice mmDevice;

    public ConnectThread(BluetoothDevice device) {
        mmDevice = device;
        BluetoothSocket tmp = null;

        // Get a BluetoothSocket for a connection with the
        // given BluetoothDevice
        try {
            tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
        } catch (IOException e) {
            Log.e(TAG, "create() failed", e);
        }
        mmSocket = tmp;
    }

    public void run() {
        Log.i(TAG, "BEGIN mConnectThread");
        setName("ConnectThread");

        // Always cancel discovery because it will slow down a connection
        mAdapter.cancelDiscovery();

        // Make a connection to the BluetoothSocket
        try {
            // This is a blocking call and will only return on a
            // successful connection or an exception
            Log.i(TAG, "mmSocket.connect() is initiaiting in the ConnectThread");
            mmSocket.connect();
            Log.i(TAG, "mmSocket.connect() complete...");
        } catch (IOException e) {
            Log.e(TAG, "Connection attempt failed, closing the socket");
            connectionFailed();
            // Close the socket
            try {
                mmSocket.close();
            } catch (IOException e2) {
                Log.e(TAG, "unable to close() socket during connection failure", e2);
            }
            // Start the service over to restart listening mode
            BluetoothServer.this.start();
            return;
        }

        // Reset the ConnectThread because we're done
        synchronized (BluetoothServer.this) {
            mConnectThread = null;
        }

        // Start the connected thread
        connected(mmSocket, mmDevice);
    }

    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) {
            Log.e(TAG, "close() of connect socket failed", e);
        }
    }
}

/**
 * This thread runs during a connection with a remote device.
 * It handles all incoming and outgoing transmissions.
 */
private class ConnectedThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final InputStream mmInStream;
    private final OutputStream mmOutStream;

    public ConnectedThread(BluetoothSocket socket) {
        Log.d(TAG, "create ConnectedThread");
        mmSocket = socket;
        InputStream tmpIn = null;
        OutputStream tmpOut = null;

        // Get the BluetoothSocket input and output streams
        try {
            tmpIn = socket.getInputStream();
            tmpOut = socket.getOutputStream();
        } catch (IOException e) {
            Log.e(TAG, "temp sockets not created", e);
        }

        mmInStream = tmpIn;
        mmOutStream = tmpOut;
    }

    public void run() {
        Log.i(TAG, "BEGIN mConnectedThread");
        byte[] buffer = new byte[1024];
        int bytes;

        // Keep listening to the InputStream while connected
        while (true) {
            try {
                // Read from the InputStream
                bytes = mmInStream.read(buffer);

                // Send the obtained bytes to the UI Activity
                mHandler.obtainMessage(Bluetooth.MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "disconnected", e);
                connectionLost();
                break;
            }
        }
    }

O código Android foi adotado no exemplo de bate -papo Bluetooth aqui

Answer 1

Você tem algum serviço (normalmente acima do RFCOMM/SPP) com UUID {0, 0, 0, 0xabcd} em execução no dispositivo Android?

Provavelmente você (criará programaticamente o serviço com o UUID especificado e o executará no dispositivo para poder se conectar a ele.

Citando da documentação do Android:

**

public BluetoothServerSocket listenUsingRfcommWithServiceRecord (String name, UUID uuid)
Create a listening, secure RFCOMM Bluetooth socket with Service Record.
A remote device connecting to this socket will be authenticated and communication on this socket will be encrypted.
Use accept() to retrieve incoming connections from a listening BluetoothServerSocket.
The system will assign an unused RFCOMM channel to listen on.
The system will also register a Service Discovery Protocol (SDP) record with the local SDP server containing the specified UUID, service name, and auto-assigned channel. Remote Bluetooth devices can use the same UUID to query our SDP server and discover which channel to connect to. This SDP record will be removed when this socket is closed, or if this application closes unexpectedly.
Use createRfcommSocketToServiceRecord(UUID) to connect to this socket from another device using the same UUID.

**