CODEWITHSUNDEEP
pythonbluetoothhidbluez
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Reputation: 457

Writing HID service with PyBluez

Need to emulate HID device on Linux using PyBluez. I have a HID devices (which I'm going to emulate). sdptool browse command shows me that it provides the following service

Service Name: HID service
Service RecHandle: 0x10001
Service Class ID List:
  "Human Interface Device" (0x1124)
Protocol Descriptor List:
  "L2CAP" (0x0100)
    PSM: 17
  "HIDP" (0x0011)
Language Base Attr List:
  code_ISO639: 0x656e
  encoding:    0x6a
  base_offset: 0x100
Profile Descriptor List:
  "Human Interface Device" (0x1124)
    Version: 0x0101

So I need to create a service with python equivalent to this. The problem is that it absolutely ignores Service class ID list that I provide.

Here is the code:

from bluetooth import *

server_sock=BluetoothSocket(L2CAP)
server_sock.bind(("", 17))
server_sock.listen(1)

uuid = "1f16e7c0-b59b-11e3-95d2-0002a5d5c51b"

advertise_service( server_sock, "PyBluez TEST",
                   service_id = uuid,
                   service_classes = [ HID_CLASS ],
                   profiles = [ HID_PROFILE ])

print("Waiting for connection on L2CAP")

try:
    client_sock, client_info = server_sock.accept()
    print("Accepted connection from ", client_info)

    while True:
        data = client_sock.recv(1024)
        if len(data) == 0:
                break
        print("received [%s]" % data)
except IOError:
    pass
except KeyboardInterrupt:
    print "Stopping..."
    stop_advertising(server_sock)
    sys.exit()  

print("disconnected")

client_sock.close()
server_sock.close()
print("all done")

and now I run sdptool using another bluetooth adapter and here is what I see

Service Name: PyBluez TEST
Service RecHandle: 0x10011
Protocol Descriptor List:
  "L2CAP" (0x0100)
    PSM: 17
Profile Descriptor List:
  "Human Interface Device" (0x1124)
    Version: 0x0100

Where is Service Class ID List?

According to this book (page 65) it should be there, but it's not.

Here is also HCI configuration

hci0:   Type: BR/EDR  Bus: USB
    BD Address: 00:17:9A:3F:54:6F  ACL MTU: 1017:8  SCO MTU: 64:0
    UP RUNNING PSCAN 
    RX bytes:37882 acl:320 sco:0 events:949 errors:0
    TX bytes:41443 acl:352 sco:0 commands:629 errors:0
    Features: 0xff 0xff 0x8d 0xfe 0x9b 0xf9 0x00 0x80
    Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
    Link policy: RSWITCH HOLD SNIFF PARK 
    Link mode: SLAVE ACCEPT 
    Name: 'My HID Device'
    Class: 0x6e0100
    Service Classes: Networking, Rendering, Capturing, Audio, Telephony
    Device Class: Computer, Uncategorized
    HCI Version: 2.0 (0x3)  Revision: 0x403d
    LMP Version: 2.0 (0x3)  Subversion: 0x430e
    Manufacturer: Broadcom Corporation (15)

I would be happy to get any help on this. Books, documentation, examples... anything, that might help with emulation of HID device.

** UPDATE **

Looks like I also have a problems on connection level. My HID host automatically disconnects after pairing.

Is it generally possible to make my Bluetooth adapter behave like a HID device and how?

Upvotes: 4

Views: 5989

Answers (1)

xuhcc
xuhcc

Reputation: 2470

You can set service class uuid with the sdptool:

sdptool setseq 0x10011 0x0001 u0x1124

but it has limited capabilities.

I have found another way to advertise service using dbus-python library:

import dbus

def advertise_service(sdp_record_xml):
    bus = dbus.SystemBus()
    manager = dbus.Interface(bus.get_object("org.bluez", "/"),
                             "org.bluez.Manager")
    adapter_path = manager.FindAdapter(self.device_id)
    service = dbus.Interface(bus.get_object("org.bluez", adapter_path),
                             "org.bluez.Service")
    service.AddRecord(sdp_record_xml)

And here is an example of the XML SDP record:

<?xml version="1.0" encoding="utf-8" ?>
<record>
    <attribute id="0x0001">
        <!-- ServiceClassIDList -->
        <sequence>
            <uuid value="00000000-0000-1000-8000-00805F9B34FB" />
        </sequence>
    </attribute>
    <attribute id="0x0003">
        <!-- ServiceID -->
        <uuid value="00000000-0000-1000-8000-00805F9B34FB" />
    </attribute>
    <attribute id="0x0004">
        <!-- ProtocolDescriptorList -->
        <sequence>
            <sequence>
                <uuid value="0x0100" />
            </sequence>
            <sequence>
                <uuid value="0x0003" />
                <uint8 value="0x3" />  <!-- RFCOMM channel -->
            </sequence>
        </sequence>
    </attribute>
    <attribute id="0x0005">
        <!-- BrowseGroupList -->
        <sequence>
            <uuid value="0x1002" />
        </sequence>
    </attribute>
    <attribute id="0x0100">
        <!-- Service name -->
        <text value="My Service" />
    </attribute>
</record>

Upvotes: 3

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