[Windows] Fixed ppi_geotag (#479)

* Fixed ppi_geotag on windows

and added tests

* More tests + static EPOCH

scapy/contrib/ppi_geotag.py

@@ -10,11 +10,14 @@
 """
 PPI-GEOLOCATION tags
 """
-import struct
+import struct, time
 from scapy.packet import *
 from scapy.fields import *
 from scapy.contrib.ppi import PPIGenericFldHdr,addPPIType
 
+# On windows, epoch is 01/02/1970 at 00:00
+EPOCH = time.mktime((1970, 1, 2, 0, 0, 0, 0, 0, 0))-86400
+
 CURR_GEOTAG_VER = 2 #Major revision of specification
 
 PPI_GPS     = 30002
@@ -154,10 +157,15 @@ class NSCounter_Field(LEIntField):
         return "%1.9f"%(y)
 
 class UTCTimeField(IntField):
-    def __init__(self, name, default, epoch=time.gmtime(0), strf="%a, %d %b %Y %H:%M:%S +0000"):
+    __slots__ = ["epoch", "delta", "strf"]
+    def __init__(self, name, default, epoch=None, strf="%a, %d %b %Y %H:%M:%S +0000"):
         IntField.__init__(self, name, default)
-        self.epoch = epoch
-        self.delta = time.mktime(epoch) - time.mktime(time.gmtime(0))
+        if epoch is None:
+            mk_epoch = EPOCH
+        else:
+            mk_epoch = time.mktime(epoch)
+        self.epoch = mk_epoch
+        self.delta = mk_epoch - EPOCH
         self.strf = strf
     def i2repr(self, pkt, x):
         if x is None:
@@ -168,11 +176,9 @@ class UTCTimeField(IntField):
 
 class LETimeField(UTCTimeField,LEIntField):
     __slots__ = ["epoch", "delta", "strf"]
-    def __init__(self, name, default, epoch=time.gmtime(0), strf="%a, %d %b %Y %H:%M:%S +0000"):
+    def __init__(self, name, default, epoch=None, strf="%a, %d %b %Y %H:%M:%S +0000"):
         LEIntField.__init__(self, name, default)
-        self.epoch = epoch
-        self.delta = time.mktime(epoch) - time.mktime(time.gmtime(0))
-        self.strf = strf
+        UTCTimeField.__init__(self, name, default, epoch=epoch, strf=strf)
 
 class SignedByteField(Field):
     def __init__(self, name, default):

scapy/contrib/ppi_geotag.uts

+# PPI_Geotag tests
+
+############
+############
++ PPI Geotags tests
+
+= Import PPI Geotag
+
+from scapy.contrib.ppi_geotag import *
+
+= Test GPS dissection
+
+assert str(GPS()) == '2u\x08\x00\x02\x00\x08\x00\x00\x00\x00\x00'
+
+= Test Vector dissection
+
+assert str(Vector()) == '3u\x08\x00\x02\x00\x08\x00\x00\x00\x00\x00'
+
+= Test Sensor dissection
+
+assert str(Sensor()) == '4u\x08\x00\x02\x00\x08\x00\x00\x00\x00\x00'
+
+= Test Antenna dissection
+
+assert str(Antenna()) == '5u\x08\x00\x02\x00\x08\x00\x00\x00\x00\x00'
+
+= Test GPSTime_Field time handling
+
+assert GPSTime_Field("GPSTime", None).delta == 0.0
+
+= Test UTCTimeField with time values
+
+local_time = time.localtime()
+utc_time = UTCTimeField("Test", None, epoch=local_time)
+assert time.localtime(utc_time.epoch) == time.localtime()
+assert time.gmtime(utc_time.delta) == time.localtime()
+assert utc_time.i2repr(None, None) == (time.strftime("%a, %d %b %Y %H:%M:%S +0000", local_time) + " (" + str(int(utc_time.delta)) + ")")
+
+= Test LETimeField with time values
+
+local_time = time.localtime()
+lme_time = LETimeField("Test", None, epoch=local_time)
+assert time.localtime(lme_time.epoch) == local_time
+assert time.gmtime(lme_time.delta) == local_time
+assert lme_time.i2repr(None, None) == (time.strftime("%a, %d %b %Y %H:%M:%S +0000", local_time) + " (" + str(int(lme_time.delta)) + ")")