blescan.py

# based on https://github.com/switchdoclabs/iBeacon-Scanner-

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

LE_META_EVENT = 0x3e
LE_PUBLIC_ADDRESS = 0x00
LE_RANDOM_ADDRESS = 0x01
LE_SET_SCAN_PARAMETERS_CP_SIZE = 7
OGF_LE_CTL = 0x08
OCF_LE_SET_SCAN_PARAMETERS = 0x000B
OCF_LE_SET_SCAN_ENABLE = 0x000C
OCF_LE_CREATE_CONN = 0x000D

LE_ROLE_MASTER = 0x00
LE_ROLE_SLAVE = 0x01

# these are actually subevents of LE_META_EVENT
EVT_LE_CONN_COMPLETE = 0x01
EVT_LE_ADVERTISING_REPORT = 0x02
EVT_LE_CONN_UPDATE_COMPLETE = 0x03
EVT_LE_READ_REMOTE_USED_FEATURES_COMPLETE = 0x04

# Advertisment event types
ADV_IND = 0x00
ADV_DIRECT_IND = 0x01
ADV_SCAN_IND = 0x02
ADV_NONCONN_IND = 0x03
ADV_SCAN_RSP = 0x04


def returnnumberpacket(pkt):
    integer = 0
    multiple = 256
    for c in pkt:
        integer += struct.unpack('B', bytes([c]))[0] * multiple
        multiple = 1
    return integer


def returnstringpacket(pkt):
    string = ''
    for c in pkt:
        string += '%02x' % struct.unpack('B', bytes([c]))[0]
    return string


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


def get_packed_bdaddr(bdaddr_string):
    packable_addr = []
    addr = bdaddr_string.split(':')
    addr.reverse()
    for b in addr:
        packable_addr.append(int(b, 16))
    return struct.pack('<BBBBBB', *packable_addr)


def packed_bdaddr_to_string(bdaddr_packed):
    return ':'.join('%02x' % i for i in struct.unpack("<BBBBBB", bdaddr_packed[::-1]))


def hci_enable_le_scan(sock):
    hci_toggle_le_scan(sock, 0x01)


def hci_disable_le_scan(sock):
    hci_toggle_le_scan(sock, 0x00)


def hci_toggle_le_scan(sock, enable):
    cmd_pkt = struct.pack("<BB", enable, 0x00)
    bluez.hci_send_cmd(sock, OGF_LE_CTL, OCF_LE_SET_SCAN_ENABLE, cmd_pkt)


def hci_le_set_scan_parameters(sock):
    old_filter = sock.getsockopt(bluez.SOL_HCI, bluez.HCI_FILTER, 14)

    SCAN_RANDOM = 0x01
    OWN_TYPE = SCAN_RANDOM
    SCAN_TYPE = 0x01


def parse_events(sock, loop_count=100):
    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)
    beacons = []
    for i in range(0, loop_count):
        pkt = sock.recv(255)
        ptype, event, plen = struct.unpack('BBB', pkt[:3])

        if event == LE_META_EVENT:
            subevent, = struct.unpack('B', pkt[3:4])
            pkt = pkt[4:]
            if subevent == EVT_LE_CONN_COMPLETE:
                le_handle_connection_complete(pkt)
            elif subevent == EVT_LE_ADVERTISING_REPORT:
                num_reports = struct.unpack('B', pkt[0:1])[0]
                report_pkt_offset = 0
                for i in range(0, num_reports):
                    beacons.append({
                        'uuid': returnstringpacket(pkt[report_pkt_offset - 22: report_pkt_offset - 6]),
                        'minor': returnnumberpacket(pkt[report_pkt_offset - 4: report_pkt_offset - 2]),
                        'major': returnnumberpacket(pkt[report_pkt_offset - 6: report_pkt_offset - 4])
                    })
                done = True
    sock.setsockopt(bluez.SOL_HCI, bluez.HCI_FILTER, old_filter)
    return beacons