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Add automatic channel scanning #51

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Add automatic channel scanning #51

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46 changes: 37 additions & 9 deletions nrf802154_sniffer/nrf802154_sniffer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,10 @@ class Nrf802154Sniffer(object):
CTRL_ARG_CHANNEL = 0
CTRL_ARG_LOGGER = 6

# Channel Ranges
CHANNEL_MIN = 11
CHANNEL_MAX = 26

# Pattern for packets being printed over serial.
RCV_REGEX = 'received:\s+([0-9a-fA-F]+)\s+power:\s+(-?\d+)\s+lqi:\s+(\d+)\s+time:\s+(-?\d+)'

Expand All @@ -91,6 +95,7 @@ def __init__(self, connection_open_timeout=None):
self.logger = logging.getLogger(__name__)
self.dev = None
self.channel = None
self.discard = threading.Event()
self.dlt = None
self.threads = []
self.connection_open_timeout = connection_open_timeout
Expand Down Expand Up @@ -218,16 +223,21 @@ def extcap_config(option):
values = []
res =[]

args.append ( (0, '--channel', 'Channel', 'IEEE 802.15.4 channel', 'selector', '{required=true}{default=11}') )
args.append ( (0, '--channel', 'Channel', 'IEEE 802.15.4 channel', 'selector',
'{required=true}{default='+str(Nrf802154Sniffer.CHANNEL_MIN)+'}') )
args.append ( (1, '--metadata', 'Out-Of-Band meta-data',
'Packet header containing out-of-band meta-data for channel, RSSI and LQI',
'selector', '{default=none}') )
args.append ( (2, '--channel-scan-interval', 'Channel scan interval',
'Automatic channel scan interval in seconds, 0: disable scanning',
'integer', '{default=0}') )

if len(option) <= 0:
for arg in args:
res.append("arg {number=%d}{call=%s}{display=%s}{tooltip=%s}{type=%s}%s" % arg)

values = values + [ (0, "%d" % i, "%d" % i, "true" if i == 11 else "false" ) for i in range(11,27) ]
values = values + [ (0, "%d" % i, "%d" % i, "true" if i == Nrf802154Sniffer.CHANNEL_MIN else "false" )
for i in range(Nrf802154Sniffer.CHANNEL_MIN,Nrf802154Sniffer.CHANNEL_MAX+1) ]

values.append ( (1, "none", "None", "true") )
values.append ( (1, "ieee802154-tap", "IEEE 802.15.4 TAP", "false") )
Expand Down Expand Up @@ -399,21 +409,33 @@ def serial_reader(self, dev, channel, queue):
buf += ch
else:
m = re.search(self.RCV_REGEX, str(buf))
buf = b''
if self.discard.is_set():
continue
if m:
packet = a2b_hex(m.group(1)[:-4])
rssi = int(m.group(2))
lqi = int(m.group(3))
timestamp = int(m.group(4)) & 0xffffffff
channel = int(channel)
channel = int(self.channel)
queue.put(self.pcap_packet(packet, self.dlt, channel, rssi, lqi, self.correct_time(timestamp)))
buf = b''

except (serialutil.SerialException, serialutil.SerialTimeoutException) as e:
self.logger.error("Cannot communicate with serial device: {} reason: {}".format(dev, e))
finally:
self.setup_done.set() # In case it wasn't set before.
if self.running.is_set(): # Another precaution.
self.stop_sig_handler()

def channel_scanner(self, channel_scan_interval):
while self.running.is_set():
time.sleep(channel_scan_interval)
self.discard.set()
self.channel = Nrf802154Sniffer.CHANNEL_MIN if self.channel == Nrf802154Sniffer.CHANNEL_MAX else self.channel + 1
self.serial_queue.put(b'channel ' + bytes(str(self.channel).encode()))
# Discard packets in the buffers so they don't get mislabelled with the wrong channels
time.sleep(0.5)
self.discard.clear()

def fifo_writer(self, fifo, queue):
"""
Expand All @@ -435,7 +457,7 @@ def fifo_writer(self, fifo, queue):
except Queue.Empty:
pass

def extcap_capture(self, fifo, dev, channel, metadata=None, control_in=None, control_out=None):
def extcap_capture(self, fifo, dev, channel, metadata=None, control_in=None, control_out=None, channel_scan_interval=None):
"""
Main method responsible for starting all other threads. In case of standalone execution this method will block
until SIGTERM/SIGINT and/or stop_sig_handler disables the loop via self.running event.
Expand All @@ -445,7 +467,7 @@ def extcap_capture(self, fifo, dev, channel, metadata=None, control_in=None, con
raise RuntimeError("Old threads were not joined properly")

packet_queue = Queue.Queue()
self.channel = channel
self.channel = int(channel)
self.dev = dev
self.running.set()

Expand All @@ -461,6 +483,8 @@ def extcap_capture(self, fifo, dev, channel, metadata=None, control_in=None, con
# TODO: Add toolbar with channel selector (channel per interface?)
if control_in:
self.threads.append(threading.Thread(target=self.control_reader, args=(control_in,)))
if channel_scan_interval:
self.threads.append(threading.Thread(target=self.channel_scanner, args=(channel_scan_interval,), name="channel_scanner"))

self.threads.append(threading.Thread(target=self.serial_reader, args=(self.dev, self.channel, packet_queue), name="serial_reader"))
self.threads.append(threading.Thread(target=self.serial_writer, name="serial_writer"))
Expand Down Expand Up @@ -490,13 +514,17 @@ def parse_args():
parser.add_argument("--extcap-control-in", help="Used to get control messages from toolbar")
parser.add_argument("--extcap-control-out", help="Used to send control messages to toolbar")

parser.add_argument("--channel", help="IEEE 802.15.4 capture channel [11-26]")
parser.add_argument("--channel", help="IEEE 802.15.4 capture channel [{}-{}]".format(Nrf802154Sniffer.CHANNEL_MIN, Nrf802154Sniffer.CHANNEL_MAX))
parser.add_argument("--channel-scan-interval", help="Automatic channel scan interval in seconds, 0: disable scanning", type=int)
parser.add_argument("--metadata", help="Meta-Data type to use for captured packets")

result, unknown = parser.parse_known_args()

if result.capture and not result.extcap_interface:
parser.error("--extcap-interface is required if --capture is present")

if result.channel_scan_interval and result.channel_scan_interval < 0:
parser.error("--channel-scan-interval must be a positive integer")

return result

Expand Down Expand Up @@ -528,10 +556,10 @@ def __repr__(self):
print(sniffer_comm.extcap_config(option))

if args.capture and args.fifo:
channel = args.channel if args.channel else 11
channel = args.channel if args.channel else Nrf802154Sniffer.CHANNEL_MIN
signal.signal(signal.SIGINT, sniffer_comm.stop_sig_handler)
signal.signal(signal.SIGTERM, sniffer_comm.stop_sig_handler)
try:
sniffer_comm.extcap_capture(args.fifo, args.extcap_interface, channel, args.metadata, args.extcap_control_in, args.extcap_control_out)
sniffer_comm.extcap_capture(args.fifo, args.extcap_interface, channel, args.metadata, args.extcap_control_in, args.extcap_control_out, args.channel_scan_interval)
except KeyboardInterrupt as e:
sniffer_comm.stop_sig_handler()