The sdpd daemon keeps track of the Bluetooth services registered on the host and responds to Service Discovery inquiries from the remote Bluetooth devices.
In order to use any service remote Bluetooth device need to send Service Search and Service Attribute or Service Search Attribute request over Bluetooth L2CAP connection on SDP PSM (0x0001). The sdpd daemon will try to find matching Service Record in its Service Database and will send appropriate response back. The remote device then will process the response, extract all required information and will make a separate connection in order to use the service.
Bluetooth applications, running on the host, register services with the local sdpd daemon. Operation like service registration, service removal and service change are performed over the control socket. It is possible to query entire content of the sdpd Service Database with sdpcontrol(8) by issuing browse command on the control socket.
The command line options are as follows: