Tshark is optional, falls-back to Wash for WPS-detection.

Should resolve #77

wifite/tools/tshark.py

@@ -10,6 +10,10 @@ class Tshark(object):
     def __init__(self):
         pass
 
+    @staticmethod
+    def exists():
+        return Process.exists('tshark')
+
     @staticmethod
     def check_for_wps_and_update_targets(capfile, targets):
         '''
@@ -21,9 +25,9 @@ class Tshark(object):
                 capfile - .cap file from airodump containing packets
                 targets - list of Targets from scan, to be updated
         '''
-        # Tshark is required to detect WPS networks
-        if not Process.exists('tshark'):
-            return
+
+        if not Tshark.exists():
+            raise Exception('Cannot detect WPS networks: Tshark does not exist')
 
         command = [
             'tshark',
@@ -38,7 +42,6 @@ class Tshark(object):
         ]
         p = Process(command)
 
-
         try:
             p.wait()
             lines = p.stdout()