Allow listening for wireless capture on serial interfaces

node/scan.py

@@ -15,125 +15,194 @@
 import logging
 import statistics
 import atexit
+import serial
+
 logger = logging.getLogger('scan.py')
 
 import requests
 
-def restart_wifi():
-    os.system("/sbin/ifdown --force wlan0")
-    os.system("/sbin/ifup --force wlan0")
-    os.system("iwconfig wlan0 mode managed")
-    while True:
-        ping_response = subprocess.Popen(
-            ["/bin/ping", "-c1", "-w100", "lf.internalpositioning.com"], stdout=subprocess.PIPE).stdout.read()
-        if '64 bytes' in ping_response.decode('utf-8'):
-            break
-        time.sleep(1)
-
-
-def num_wifi_cards():
-    cmd = 'iwconfig'
-    p = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
-                         stdout=subprocess.PIPE, stderr=subprocess.STDOUT, close_fds=True)
-    output = p.stdout.read().decode('utf-8')
-    return output.count("wlan")
-
+class BaseScan:
+    def __init__(self, timeout):
+        self.timeout = timeout
 
-def process_scan(time_window):
-    logger.debug("Reading files...")
-    output = ""
-    maxFileNumber = -1
-    fileNameToRead = ""
-    for filename in glob.glob("/tmp/tshark-temp*"):
-        fileNumber = int(filename.split("_")[1])
-        if fileNumber > maxFileNumber:
-            maxFileNumber = fileNumber
-            fileNameToRead = filename
-
-    logger.debug("Reading from %s" % fileNameToRead)
-    cmd = subprocess.Popen(("tshark -r "+fileNameToRead+" -T fields -e frame.time_epoch -e wlan.sa -e wlan.bssid -e radiotap.dbm_antsignal").split(
-    ), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-    output += cmd.stdout.read().decode('utf-8')
-
-    timestamp_threshold = float(time.time()) - float(time_window)
-    fingerprints = {}
-    relevant_lines = 0
-    for line in output.splitlines():
-        try:
-            timestamp, mac, mac2, power_levels = line.split("\t")
-
-            if mac == mac2 or float(timestamp) < timestamp_threshold or len(mac) == 0:
+    def get_payload(self, fingerprints):
+        # Compute medians
+        fingerprints2 = []
+        for mac in fingerprints:
+            if len(fingerprints[mac]) == 0:
                 continue
-
-            relevant_lines+=1
-            rssi = power_levels.split(',')[0]
-            if len(rssi) == 0:
+            print(mac)
+            print(fingerprints[mac])
+            fingerprints2.append(
+                {"mac": mac, "rssi": int(statistics.median(fingerprints[mac]))})
+
+        logger.debug("Found %d fingerprints" % len(fingerprints2))
+
+        payload = {
+            "node": socket.gethostname(),
+            "signals": fingerprints2,
+            "timestamp": int(
+                time.time())}
+        logger.debug(payload)
+        return payload
+
+
+class SerialScan(BaseScan):
+    """
+    Class to implement mac/rssi finding via a serial device that outputs
+    periodic list of mac/rssi.
+
+    Protocol is to pass lines in the format of "mac_address rssi packet_count"
+    at 115200bps.
+    """
+    def __init__(self, interface, timeout):
+        BaseScan.__init__(self, timeout)
+
+        self.interface = interface
+
+    def do_scan(self):
+        # Sleep then read all the data non-blocking until nothing left.
+        # Hopefully the internal buffers are big enough to hold it all.
+        ser = serial.Serial("/dev/%s" % self.interface, baudrate = 115200, timeout = 0);
+        time.sleep(self.timeout)
+        inp = ''
+        while True:
+            read = ser.read(10000)
+            if len(read) == 0:
+                break;
+            inp += str(read, encoding='ascii')
+        ser.close();
+
+        fingerprints = {}
+        for line in inp.splitlines():
+            if line.startswith("-"):
                 continue
 
+            mac, rssi, packets = line.split(" ")
             if mac not in fingerprints:
                 fingerprints[mac] = []
-            fingerprints[mac].append(float(rssi))
-        except:
-            pass
-    logger.debug("..done")
-
-    # Compute medians
-    fingerprints2 = []
-    for mac in fingerprints:
-        if len(fingerprints[mac]) == 0:
-            continue
-        print(mac)
-        print(fingerprints[mac])
-        fingerprints2.append(
-            {"mac": mac, "rssi": int(statistics.median(fingerprints[mac]))})
-
-    logger.debug("Processed %d lines, found %d fingerprints in %d relevant lines" %
-                 (len(output.splitlines()), len(fingerprints2),relevant_lines))
-
-    payload = {
-        "node": socket.gethostname(),
-        "signals": fingerprints2,
-        "timestamp": int(
-            time.time())}
-    logger.debug(payload)
-    return payload
-
-
-def run_command(command):
-    p = subprocess.Popen(
-        command.split(),
-        stdout=subprocess.PIPE,
-        stderr=subprocess.STDOUT)
-    return iter(p.stdout.readline, b'')
-
-
-def tshark_is_running():
-    ps_output = subprocess.Popen(
-        "ps aux".split(), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-    ps_stdout = ps_output.stdout.read().decode('utf-8')
-    isRunning = 'tshark' in ps_stdout and '[tshark]' not in ps_stdout
-    logger.debug("tshark is running: " + str(isRunning))
-    return isRunning
-
-
-def start_scan(wlan):
-    if not tshark_is_running():
+
+            for i in range(0, int(packets)):
+                fingerprints[mac].append(float(rssi))
+
+        return self.get_payload(fingerprints)
+
+
+class WifiScan(BaseScan):
+    """
+    Class to implement mac/rssi finding via a tshark scan of a device in
+    monitor mode
+    """
+    def __init__(self, interface, timeout, single_wifi):
+        BaseScan.__init__(self, timeout)
+
+        atexit.register(self.exit_handler)
+        self.single_wifi = single_wifi
+        self.interface = interface
+
+    def do_scan(self):
+        if self.single_wifi:
+            logger.debug("Stopping scan...")
+            if self.tshark_is_running():
+                self.stop_scan()
+            logger.debug("Stopping monitor mode...")
+            self.restart_wifi()
+            logger.debug("Restarting WiFi in managed mode...")
+
+        if not self.tshark_is_running():
+            self.start_scan()
+
+        time.sleep( self.timeout )
+        return self.process_scan()
+
+    def exit_handler(self):
+        print("Exiting...stopping scan..")
+        os.system("pkill -9 tshark")
+
+    def restart_wifi(self):
+        os.system("/sbin/ifdown --force wlan0")
+        os.system("/sbin/ifup --force wlan0")
+        os.system("iwconfig wlan0 mode managed")
+        while True:
+            ping_response = subprocess.Popen(
+                ["/bin/ping", "-c1", "-w100", "lf.internalpositioning.com"], stdout=subprocess.PIPE).stdout.read()
+            if '64 bytes' in ping_response.decode('utf-8'):
+                break
+            time.sleep(1)
+
+
+    def process_scan(self):
+        logger.debug("Reading files...")
+        output = ""
+        maxFileNumber = -1
+        fileNameToRead = ""
+        for filename in glob.glob("/tmp/tshark-temp*"):
+            fileNumber = int(filename.split("_")[1])
+            if fileNumber > maxFileNumber:
+                maxFileNumber = fileNumber
+                fileNameToRead = filename
+
+        logger.debug("Reading from %s" % fileNameToRead)
+        cmd = subprocess.Popen(("tshark -r "+fileNameToRead+" -T fields -e frame.time_epoch -e wlan.sa -e wlan.bssid -e radiotap.dbm_antsignal").split(
+        ), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        output += cmd.stdout.read().decode('utf-8')
+
+        timestamp_threshold = float(time.time()) - float(self.timeout)
+        fingerprints = {}
+        relevant_lines = 0
+        for line in output.splitlines():
+            try:
+                timestamp, mac, mac2, power_levels = line.split("\t")
+
+                if mac == mac2 or float(timestamp) < timestamp_threshold or len(mac) == 0:
+                    continue
+
+                relevant_lines+=1
+                rssi = power_levels.split(',')[0]
+                if len(rssi) == 0:
+                    continue
+
+                if mac not in fingerprints:
+                    fingerprints[mac] = []
+                fingerprints[mac].append(float(rssi))
+            except:
+                pass
+        logger.debug("..done (%d lines of which %d were relevant)" % (len(output.splitlines)(), relevant_lines))
+
+        return self.get_payload(fingerprints)
+
+    def tshark_is_running(self):
+        ps_output = subprocess.Popen(
+            "ps aux".split(), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        ps_stdout = ps_output.stdout.read().decode('utf-8')
+        isRunning = 'tshark' in ps_stdout and '[tshark]' not in ps_stdout
+        logger.debug("tshark is running: " + str(isRunning))
+        return isRunning
+
+
+    def start_scan(self):
         # Remove previous files
         for filename in glob.glob("/tmp/tshark-temp*"):
             os.remove(filename)
-        subprocess.Popen(("/usr/bin/tshark -I -i " + wlan + " -b files:4 -b filesize:1000 -w /tmp/tshark-temp").split(),
+        subprocess.Popen(("/usr/bin/tshark -I -i " + self.interface + " -b files:4 -b filesize:1000 -w /tmp/tshark-temp").split(),
                          stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        if tshark_is_running():
+        if self.tshark_is_running():
             logger.info("Starting scan")
 
 
-def stop_scan():
-    if tshark_is_running():
+    def stop_scan(self):
         os.system("pkill -9 tshark")
-        if not tshark_is_running():
+        if not self.tshark_is_running():
             logger.info("Stopped scan")
 
 
+def num_wifi_cards():
+    cmd = 'iwconfig'
+    p = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
+                         stdout=subprocess.PIPE, stderr=subprocess.STDOUT, close_fds=True)
+    output = p.stdout.read().decode('utf-8')
+    return output.count("wlan")
+
 def main():
     # Check if SUDO
     # http://serverfault.com/questions/16767/check-admin-rights-inside-python-script
@@ -156,7 +225,7 @@ def main():
         "-i",
         "--interface",
         default=default_wlan,
-        help="Interface to listen on - default %s" % default_wlan)
+        help="Interface or tty to listen on - default %s" % default_wlan)
     parser.add_argument(
         "-t",
         "--time",
@@ -202,16 +271,14 @@ def main():
     print("Using group " + args.group)
     logger.debug("Using group " + args.group)
 
+    if args.interface.startswith("ttyS"):
+        scanner = SerialScan(args.interface, float(args.time))
+    else:
+        scanner = WifiScan(args.interface, float(args.time), args.single_wifi)
+
     while True:
         try:
-            if args.single_wifi:
-                logger.debug("Stopping scan...")
-                stop_scan()
-                logger.debug("Stopping monitor mode...")
-                restart_wifi()
-                logger.debug("Restarting WiFi in managed mode...")
-            start_scan(args.interface)
-            payload = process_scan(args.time)
+            payload = scanner.do_scan()
             payload['group'] = args.group
             if len(payload['signals']) > 0:
                 r = requests.post(
@@ -220,16 +287,8 @@ def main():
                     json=payload)
                 logger.debug(
                     "Sent to server with status code: " + str(r.status_code))
-            time.sleep(float(args.time))  # Wait before getting next window
         except Exception:
             logger.error("Fatal error in main loop", exc_info=True)
-            time.sleep(float(args.time))
-
-
-def exit_handler():
-    print("Exiting...stopping scan..")
-    os.system("pkill -9 tshark")
 
 if __name__ == "__main__":
-    atexit.register(exit_handler)
     main()