Bluetooth: how to create a socket for connecting to a service with specific UUID with Bluez?

1
votes

I am working with the BlueZ libraries for managing the bluetooth stack under linux. I am trying to open a socket that should connect with a specific service whose UUID is known. I have successfully tried to open sockets between a server and a client following the examples here:

http://people.csail.mit.edu/albert/bluez-intro/c404.html

where it is also described how to explore services in a remote host; however, what I cannot figure out is how to specify the UUID while connecting the socket. This is something quite straightforward on other contexts, as it happens when using Android libraries; however, with BlueZ I haven't found examples on the web.

Thanks for the help!

Stefano

-- added some details in a reply... don't know if it's right or not; if not, sorry

thanks for your help!

In my post I said I wanted to connect a socket with a specified UUID since I had in mind a function like createRfcommSocketToServiceRecord as can be found in:

http://developer.android.com/reference/android/bluetooth/BluetoothDevice.html#createRfcommSocketToServiceRecord%28java.util.UUID%29

which returns a socket given a certain UUID. I am developing two softwares, one being the client and the other the server, therefore it's a service I am creating, not a standard one. I publish such service on the server with a specified UUID, and I would like to connect to it from the client. The server is running fine, since with an android platform, exploiting the mentioned createRfcommSocketToServiceRecord method, I am able to connect to the server with the right service.

The example you posted is very clear as well, but unfortunately it is in Python, while (I forgot to point out) I am using Bluez as a C library. I am able to exploit the SDP and inspect services on a remote server; however, when it is the time of setting up the socket, I don't see how to specify the port. I thought about the rc_channel, but as far as I understood it is the bluetooth channel (ranging from 1 to 11 or something similar). Could you please point out Where I should be able to specify the port while creating the socket in the client? And where am I able to find the right port in the complex structure the sdp is dealing with? -- referred to:

http://people.csail.mit.edu/albert/bluez-intro/x604.html

Thanks again for the help!

1
socketsbluetoothsdp
What service are you attempting to connect to? To ask this another way, what kind of socket are you using? – ajpyles

1 Answers

1
votes

You don't connect sockets by UUID. You use a socket to connect to remote device and browse its SDP to discover the UUIDs it offers, and map that to a socket port. Here's an example of this process using PyBluez, python wrappers above BlueZ http://people.csail.mit.edu/albert/bluez-intro/x290.html