Test framework: StringIO fixes for Python3

Add 2/3 support to binarytomac and mactobinary and move to vpp_mac.py

Change-Id: I3dc7e4a24486aee22140c781aae7e44e58935877
Signed-off-by: Ole Troan <ot@cisco.com>
diff --git a/test/util.py b/test/util.py
index 1ab5c1f..a3ec6e3 100644
--- a/test/util.py
+++ b/test/util.py
@@ -4,7 +4,6 @@
 import sys
 import os.path
 from abc import abstractmethod, ABCMeta
-from cStringIO import StringIO
 from scapy.utils6 import in6_mactoifaceid
 
 from scapy.layers.l2 import Ether
@@ -14,11 +13,13 @@
     IPv6ExtHdrHopByHop
 from scapy.utils import hexdump
 from socket import AF_INET6
+from io import BytesIO
+from vpp_mac import mactobinary
 
 
 def ppp(headline, packet):
     """ Return string containing the output of scapy packet.show() call. """
-    o = StringIO()
+    o = BytesIO()
     old_stdout = sys.stdout
     sys.stdout = o
     print(headline)
@@ -58,11 +59,6 @@
             for ip in ip4_range(ip4, s, e))
 
 
-def mactobinary(mac):
-    """ Convert the : separated format into binary packet data for the API """
-    return mac.replace(':', '').decode('hex')
-
-
 def mk_ll_addr(mac):
     euid = in6_mactoifaceid(mac)
     addr = "fe80::" + euid
@@ -441,3 +437,29 @@
     pkts[-1][IPv6ExtHdrFragment].m = 0  # reset more-flags in last fragment
 
     return pkts
+
+
+def reassemble4_core(listoffragments, return_ip):
+    buffer = BytesIO()
+    first = listoffragments[0]
+    buffer.seek(20)
+    for pkt in listoffragments:
+        buffer.seek(pkt[IP].frag*8)
+        buffer.write(bytes(pkt[IP].payload))
+    first.len = len(buffer.getvalue()) + 20
+    first.flags = 0
+    del(first.chksum)
+    if return_ip:
+        header = bytes(first[IP])[:20]
+        return first[IP].__class__(header + buffer.getvalue())
+    else:
+        header = bytes(first[Ether])[:34]
+        return first[Ether].__class__(header + buffer.getvalue())
+
+
+def reassemble4_ether(listoffragments):
+    return reassemble4_core(listoffragments, False)
+
+
+def reassemble4(listoffragments):
+    return reassemble4_core(listoffragments, True)