inquiry-with-rssi.py

# performs a simple device inquiry, followed by a remote name request of each
# discovered device

import os
import sys
import struct
import bluetooth._bluetooth as bluez
import bluetooth

def printpacket(pkt):
    for c in pkt:
        sys.stdout.write("%02x " % struct.unpack("B",c)[0])
    print() 


def read_inquiry_mode(sock):
    """returns the current mode, or -1 on failure"""
    # save current filter
    old_filter = sock.getsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, 14)

    # Setup socket filter to receive only events related to the
    # read_inquiry_mode command
    flt = bluez.hci_filter_new()
    opcode = bluez.cmd_opcode_pack(bluez.OGF_HOST_CTL, 
            bluez.OCF_READ_INQUIRY_MODE)
    bluez.hci_filter_set_ptype(flt, bluez.HCI_EVENT_PKT)
    bluez.hci_filter_set_event(flt, bluez.EVT_CMD_COMPLETE);
    bluez.hci_filter_set_opcode(flt, opcode)
    sock.setsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, flt )

    # first read the current inquiry mode.
    bluez.hci_send_cmd(sock, bluez.OGF_HOST_CTL, 
            bluez.OCF_READ_INQUIRY_MODE )

    pkt = sock.recv(255)

    status,mode = struct.unpack("xxxxxxBB", pkt)
    if status != 0: mode = -1

    # restore old filter
    sock.setsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, old_filter )
    return mode

def write_inquiry_mode(sock, mode):
    """returns 0 on success, -1 on failure"""
    # save current filter
    old_filter = sock.getsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, 14)

    # Setup socket filter to receive only events related to the
    # write_inquiry_mode command
    flt = bluez.hci_filter_new()
    opcode = bluez.cmd_opcode_pack(bluez.OGF_HOST_CTL, 
            bluez.OCF_WRITE_INQUIRY_MODE)
    bluez.hci_filter_set_ptype(flt, bluez.HCI_EVENT_PKT)
    bluez.hci_filter_set_event(flt, bluez.EVT_CMD_COMPLETE);
    bluez.hci_filter_set_opcode(flt, opcode)
    sock.setsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, flt )

    # send the command!
    bluez.hci_send_cmd(sock, bluez.OGF_HOST_CTL, 
            bluez.OCF_WRITE_INQUIRY_MODE, struct.pack("B", mode) )

    pkt = sock.recv(255)

    status = struct.unpack("xxxxxxB", pkt)[0]

    # restore old filter
    sock.setsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, old_filter )
    if status != 0: return -1
    return 0

def device_inquiry_with_with_rssi(sock):
    # save current filter
    old_filter = sock.getsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, 14)

    # perform a device inquiry on bluetooth device #0
    # The inquiry should last 8 * 1.28 = 10.24 seconds
    # before the inquiry is performed, bluez should flush its cache of
    # previously discovered devices
    flt = bluez.hci_filter_new()
    bluez.hci_filter_all_events(flt)
    bluez.hci_filter_set_ptype(flt, bluez.HCI_EVENT_PKT)
    sock.setsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, flt )

    duration = 4
    max_responses = 255
    cmd_pkt = struct.pack("BBBBB", 0x33, 0x8b, 0x9e, duration, max_responses)
    bluez.hci_send_cmd(sock, bluez.OGF_LINK_CTL, bluez.OCF_INQUIRY, cmd_pkt)

    results = []

    done = False
    while not done:
        pkt = sock.recv(255)
        ptype, event, plen = struct.unpack("BBB", pkt[:3])
        if event == bluez.EVT_INQUIRY_RESULT_WITH_RSSI:
            pkt = pkt[3:]
            nrsp = bluetooth.get_byte(pkt[0])
            for i in range(nrsp):
                addr = bluez.ba2str( pkt[1+6*i:1+6*i+6] )
                rssi = bluetooth.byte_to_signed_int(
                        bluetooth.get_byte(pkt[1+13*nrsp+i]))
                results.append( ( addr, rssi ) )
                print("[%s] RSSI: [%d]" % (addr, rssi))
        elif event == bluez.EVT_INQUIRY_COMPLETE:
            done = True
        elif event == bluez.EVT_CMD_STATUS:
            status, ncmd, opcode = struct.unpack("BBH", pkt[3:7])
            if status != 0:
                print("uh oh...")
                printpacket(pkt[3:7])
                done = True
        elif event == bluez.EVT_INQUIRY_RESULT:
            pkt = pkt[3:]
            nrsp = bluetooth.get_byte(pkt[0])
            for i in range(nrsp):
                addr = bluez.ba2str( pkt[1+6*i:1+6*i+6] )
                results.append( ( addr, -1 ) )
                print("[%s] (no RRSI)" % addr)
        else:
            print("unrecognized packet type 0x%02x" % ptype)
        print("event ", event)


    # restore old filter
    sock.setsockopt( bluez.SOL_HCI, bluez.HCI_FILTER, old_filter )

    return results

dev_id = 0
try:
    sock = bluez.hci_open_dev(dev_id)
except:
    print("error accessing bluetooth device...")
    sys.exit(1)

try:
    mode = read_inquiry_mode(sock)
except Exception as e:
    print("error reading inquiry mode.  ")
    print("Are you sure this a bluetooth 1.2 device?")
    print(e)
    sys.exit(1)
print("current inquiry mode is %d" % mode)

if mode != 1:
    print("writing inquiry mode...")
    try:
        result = write_inquiry_mode(sock, 1)
    except Exception as e:
        print("error writing inquiry mode.  Are you sure you're root?")
        print(e)
        sys.exit(1)
    if result != 0:
        print("error while setting inquiry mode")
    print("result: %d" % result)

device_inquiry_with_with_rssi(sock)