Basic Encapsulation Example (#64)

* Adding initial implementation of basic_encap example

* Updated basic_encap example to count the number of valid packets

* Updated basic_encap example to put encapsulation layer after Ethernet
header.

* Added solution file for basic_encap example

* Changed the name of the basic_encap example to basic_tunnel and called
the new header myTunnel. Also changed the myTunnel field names slightly.

P4D2_2017_Fall/exercises/basic_tunnel/myTunnel_header.py

@@ -0,0 +1,20 @@
+
+from scapy.all import *
+import sys, os
+
+TYPE_MYTUNNEL = 0x1212
+TYPE_IPV4 = 0x0800
+
+class MyTunnel(Packet):
+    name = "MyTunnel"
+    fields_desc = [
+        ShortField("pid", 0),
+        ShortField("dst_id", 0)
+    ]
+    def mysummary(self):
+        return self.sprintf("pid=%pid%, dst_id=%dst_id%")
+
+
+bind_layers(Ether, MyTunnel, type=TYPE_MYTUNNEL)
+bind_layers(MyTunnel, IP, pid=TYPE_IPV4)
+