diff --git a/src/python/loxi/of10/action.py b/src/python/loxi/of10/action.py
index c6129a5..8fe2997 100644
--- a/src/python/loxi/of10/action.py
+++ b/src/python/loxi/of10/action.py
@@ -1,17 +1,6 @@
-#
-# Copyright 2012, 2013, Big Switch Networks, Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License"); you may
-# not use this file except in compliance with the License. You may obtain
-# a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-# License for the specific language governing permissions and limitations
-# under the License.
+# Copyright (c) 2008 The Board of Trustees of The Leland Stanford Junior University
+# Copyright (c) 2011, 2012 Open Networking Foundation
+# Copyright (c) 2012, 2013 Big Switch Networks, Inc.
 
 # Automatically generated by LOXI from template action.py
 # Do not modify
@@ -19,22 +8,15 @@
 import struct
 import const
 import util
+import loxi.generic_util
 import loxi
 
-def unpack_list(buf):
-    if len(buf) % 8 != 0: raise loxi.ProtocolError("action list length not a multiple of 8")
-    actions = []
-    offset = 0
-    while offset < len(buf):
-        type, length = struct.unpack_from("!HH", buf, offset)
-        if length == 0: raise loxi.ProtocolError("action length is 0")
-        if length % 8 != 0: raise loxi.ProtocolError("action length not a multiple of 8")
-        if offset + length > len(buf): raise loxi.ProtocolError("action length overruns list length")
-        parser = parsers.get(type)
-        if not parser: raise loxi.ProtocolError("unknown action type %d" % type)
-        actions.append(parser(buffer(buf, offset, length)))
-        offset += length
-    return actions
+def unpack_list(reader):
+    def deserializer(reader, typ):
+        parser = parsers.get(typ)
+        if not parser: raise loxi.ProtocolError("unknown action type %d" % typ)
+        return parser(reader)
+    return loxi.generic_util.unpack_list_tlv16(reader, deserializer)
 
 class Action(object):
     type = None # override in subclass
@@ -45,7 +27,7 @@
     experimenter = 0x5c16c7
     subtype = 1
 
-    def __init__(self, dest_port=None, vlan_tag=None, copy_stage=None, pad=None):
+    def __init__(self, dest_port=None, vlan_tag=None, copy_stage=None):
         if dest_port != None:
             self.dest_port = dest_port
         else:
@@ -58,10 +40,7 @@
             self.copy_stage = copy_stage
         else:
             self.copy_stage = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0]
+        return
 
     def pack(self):
         packed = []
@@ -72,7 +51,7 @@
         packed.append(struct.pack("!L", self.dest_port))
         packed.append(struct.pack("!L", self.vlan_tag))
         packed.append(struct.pack("!B", self.copy_stage))
-        packed.append(struct.pack("!3B", *self.pad))
+        packed.append('\x00' * 3)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -80,28 +59,28 @@
     @staticmethod
     def unpack(buf):
         obj = bsn_mirror()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_VENDOR)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 24: raise loxi.ProtocolError("bsn_mirror length is %d, should be 24" % _length)
-        experimenter = struct.unpack_from('!L', buf, 4)[0]
-        assert(experimenter == 0x5c16c7)
-        subtype = struct.unpack_from('!L', buf, 8)[0]
-        assert(subtype == 1)
-        obj.dest_port = struct.unpack_from('!L', buf, 12)[0]
-        obj.vlan_tag = struct.unpack_from('!L', buf, 16)[0]
-        obj.copy_stage = struct.unpack_from('!B', buf, 20)[0]
-        obj.pad = list(struct.unpack_from('!3B', buf, 21))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_VENDOR)
+        _len = reader.read('!H')[0]
+        _experimenter = reader.read('!L')[0]
+        assert(_experimenter == 0x5c16c7)
+        _subtype = reader.read('!L')[0]
+        assert(_subtype == 1)
+        obj.dest_port = reader.read('!L')[0]
+        obj.vlan_tag = reader.read('!L')[0]
+        obj.copy_stage = reader.read('!B')[0]
+        reader.skip(3)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.dest_port != other.dest_port: return False
         if self.vlan_tag != other.vlan_tag: return False
         if self.copy_stage != other.copy_stage: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -124,9 +103,6 @@
                 q.text(","); q.breakable()
                 q.text("copy_stage = ");
                 q.text("%#x" % self.copy_stage)
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
@@ -140,6 +116,7 @@
             self.dst = dst
         else:
             self.dst = 0
+        return
 
     def pack(self):
         packed = []
@@ -155,21 +132,22 @@
     @staticmethod
     def unpack(buf):
         obj = bsn_set_tunnel_dst()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_VENDOR)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 16: raise loxi.ProtocolError("bsn_set_tunnel_dst length is %d, should be 16" % _length)
-        experimenter = struct.unpack_from('!L', buf, 4)[0]
-        assert(experimenter == 0x5c16c7)
-        subtype = struct.unpack_from('!L', buf, 8)[0]
-        assert(subtype == 2)
-        obj.dst = struct.unpack_from('!L', buf, 12)[0]
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_VENDOR)
+        _len = reader.read('!H')[0]
+        _experimenter = reader.read('!L')[0]
+        assert(_experimenter == 0x5c16c7)
+        _subtype = reader.read('!L')[0]
+        assert(_subtype == 2)
+        obj.dst = reader.read('!L')[0]
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.dst != other.dst: return False
         return True
 
@@ -193,26 +171,23 @@
 class enqueue(Action):
     type = const.OFPAT_ENQUEUE
 
-    def __init__(self, port=None, pad=None, queue_id=None):
+    def __init__(self, port=None, queue_id=None):
         if port != None:
             self.port = port
         else:
             self.port = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0,0,0,0]
         if queue_id != None:
             self.queue_id = queue_id
         else:
             self.queue_id = 0
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!H", self.port))
-        packed.append(struct.pack("!6B", *self.pad))
+        packed.append('\x00' * 6)
         packed.append(struct.pack("!L", self.queue_id))
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
@@ -221,21 +196,21 @@
     @staticmethod
     def unpack(buf):
         obj = enqueue()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_ENQUEUE)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 16: raise loxi.ProtocolError("enqueue length is %d, should be 16" % _length)
-        obj.port = struct.unpack_from('!H', buf, 4)[0]
-        obj.pad = list(struct.unpack_from('!6B', buf, 6))
-        obj.queue_id = struct.unpack_from('!L', buf, 12)[0]
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_ENQUEUE)
+        _len = reader.read('!H')[0]
+        obj.port = reader.read('!H')[0]
+        reader.skip(6)
+        obj.queue_id = reader.read('!L')[0]
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.port != other.port: return False
-        if self.pad != other.pad: return False
         if self.queue_id != other.queue_id: return False
         return True
 
@@ -254,9 +229,6 @@
                 q.text("port = ");
                 q.text(util.pretty_port(self.port))
                 q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
-                q.text(","); q.breakable()
                 q.text("queue_id = ");
                 q.text("%#x" % self.queue_id)
             q.breakable()
@@ -267,15 +239,8 @@
     experimenter = 0x2320
     subtype = 18
 
-    def __init__(self, pad=None, pad2=None):
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = 0
-        if pad2 != None:
-            self.pad2 = pad2
-        else:
-            self.pad2 = 0
+    def __init__(self):
+        return
 
     def pack(self):
         packed = []
@@ -283,8 +248,8 @@
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!L", self.experimenter))
         packed.append(struct.pack("!H", self.subtype))
-        packed.append(struct.pack("!H", self.pad))
-        packed.append(struct.pack("!L", self.pad2))
+        packed.append('\x00' * 2)
+        packed.append('\x00' * 4)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -292,24 +257,23 @@
     @staticmethod
     def unpack(buf):
         obj = nicira_dec_ttl()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_VENDOR)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 16: raise loxi.ProtocolError("nicira_dec_ttl length is %d, should be 16" % _length)
-        experimenter = struct.unpack_from('!L', buf, 4)[0]
-        assert(experimenter == 0x2320)
-        subtype = struct.unpack_from('!H', buf, 8)[0]
-        assert(subtype == 18)
-        obj.pad = struct.unpack_from('!H', buf, 10)[0]
-        obj.pad2 = struct.unpack_from('!L', buf, 12)[0]
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_VENDOR)
+        _len = reader.read('!H')[0]
+        _experimenter = reader.read('!L')[0]
+        assert(_experimenter == 0x2320)
+        _subtype = reader.read('!H')[0]
+        assert(_subtype == 18)
+        reader.skip(2)
+        reader.skip(4)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
-        if self.pad != other.pad: return False
-        if self.pad2 != other.pad2: return False
         return True
 
     def __ne__(self, other):
@@ -324,11 +288,6 @@
         with q.group():
             with q.indent(2):
                 q.breakable()
-                q.text("pad = ");
-                q.text("%#x" % self.pad)
-                q.text(","); q.breakable()
-                q.text("pad2 = ");
-                q.text("%#x" % self.pad2)
             q.breakable()
         q.text('}')
 
@@ -344,6 +303,7 @@
             self.max_len = max_len
         else:
             self.max_len = 0
+        return
 
     def pack(self):
         packed = []
@@ -358,18 +318,19 @@
     @staticmethod
     def unpack(buf):
         obj = output()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_OUTPUT)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("output length is %d, should be 8" % _length)
-        obj.port = struct.unpack_from('!H', buf, 4)[0]
-        obj.max_len = struct.unpack_from('!H', buf, 6)[0]
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_OUTPUT)
+        _len = reader.read('!H')[0]
+        obj.port = reader.read('!H')[0]
+        obj.max_len = reader.read('!H')[0]
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.port != other.port: return False
         if self.max_len != other.max_len: return False
         return True
@@ -397,22 +358,19 @@
 class set_dl_dst(Action):
     type = const.OFPAT_SET_DL_DST
 
-    def __init__(self, dl_addr=None, pad=None):
+    def __init__(self, dl_addr=None):
         if dl_addr != None:
             self.dl_addr = dl_addr
         else:
             self.dl_addr = [0,0,0,0,0,0]
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0,0,0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!6B", *self.dl_addr))
-        packed.append(struct.pack("!6B", *self.pad))
+        packed.append('\x00' * 6)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -420,20 +378,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_dl_dst()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_DL_DST)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 16: raise loxi.ProtocolError("set_dl_dst length is %d, should be 16" % _length)
-        obj.dl_addr = list(struct.unpack_from('!6B', buf, 4))
-        obj.pad = list(struct.unpack_from('!6B', buf, 10))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_DL_DST)
+        _len = reader.read('!H')[0]
+        obj.dl_addr = list(reader.read('!6B'))
+        reader.skip(6)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.dl_addr != other.dl_addr: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -450,31 +408,25 @@
                 q.breakable()
                 q.text("dl_addr = ");
                 q.text(util.pretty_mac(self.dl_addr))
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 class set_dl_src(Action):
     type = const.OFPAT_SET_DL_SRC
 
-    def __init__(self, dl_addr=None, pad=None):
+    def __init__(self, dl_addr=None):
         if dl_addr != None:
             self.dl_addr = dl_addr
         else:
             self.dl_addr = [0,0,0,0,0,0]
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0,0,0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!6B", *self.dl_addr))
-        packed.append(struct.pack("!6B", *self.pad))
+        packed.append('\x00' * 6)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -482,20 +434,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_dl_src()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_DL_SRC)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 16: raise loxi.ProtocolError("set_dl_src length is %d, should be 16" % _length)
-        obj.dl_addr = list(struct.unpack_from('!6B', buf, 4))
-        obj.pad = list(struct.unpack_from('!6B', buf, 10))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_DL_SRC)
+        _len = reader.read('!H')[0]
+        obj.dl_addr = list(reader.read('!6B'))
+        reader.skip(6)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.dl_addr != other.dl_addr: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -512,9 +464,6 @@
                 q.breakable()
                 q.text("dl_addr = ");
                 q.text(util.pretty_mac(self.dl_addr))
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
@@ -526,6 +475,7 @@
             self.nw_addr = nw_addr
         else:
             self.nw_addr = 0
+        return
 
     def pack(self):
         packed = []
@@ -539,17 +489,18 @@
     @staticmethod
     def unpack(buf):
         obj = set_nw_dst()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_NW_DST)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_nw_dst length is %d, should be 8" % _length)
-        obj.nw_addr = struct.unpack_from('!L', buf, 4)[0]
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_NW_DST)
+        _len = reader.read('!H')[0]
+        obj.nw_addr = reader.read('!L')[0]
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.nw_addr != other.nw_addr: return False
         return True
 
@@ -578,6 +529,7 @@
             self.nw_addr = nw_addr
         else:
             self.nw_addr = 0
+        return
 
     def pack(self):
         packed = []
@@ -591,17 +543,18 @@
     @staticmethod
     def unpack(buf):
         obj = set_nw_src()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_NW_SRC)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_nw_src length is %d, should be 8" % _length)
-        obj.nw_addr = struct.unpack_from('!L', buf, 4)[0]
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_NW_SRC)
+        _len = reader.read('!H')[0]
+        obj.nw_addr = reader.read('!L')[0]
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.nw_addr != other.nw_addr: return False
         return True
 
@@ -625,22 +578,19 @@
 class set_nw_tos(Action):
     type = const.OFPAT_SET_NW_TOS
 
-    def __init__(self, nw_tos=None, pad=None):
+    def __init__(self, nw_tos=None):
         if nw_tos != None:
             self.nw_tos = nw_tos
         else:
             self.nw_tos = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!B", self.nw_tos))
-        packed.append(struct.pack("!3B", *self.pad))
+        packed.append('\x00' * 3)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -648,20 +598,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_nw_tos()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_NW_TOS)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_nw_tos length is %d, should be 8" % _length)
-        obj.nw_tos = struct.unpack_from('!B', buf, 4)[0]
-        obj.pad = list(struct.unpack_from('!3B', buf, 5))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_NW_TOS)
+        _len = reader.read('!H')[0]
+        obj.nw_tos = reader.read('!B')[0]
+        reader.skip(3)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.nw_tos != other.nw_tos: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -678,31 +628,25 @@
                 q.breakable()
                 q.text("nw_tos = ");
                 q.text("%#x" % self.nw_tos)
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 class set_tp_dst(Action):
     type = const.OFPAT_SET_TP_DST
 
-    def __init__(self, tp_port=None, pad=None):
+    def __init__(self, tp_port=None):
         if tp_port != None:
             self.tp_port = tp_port
         else:
             self.tp_port = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!H", self.tp_port))
-        packed.append(struct.pack("!2B", *self.pad))
+        packed.append('\x00' * 2)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -710,20 +654,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_tp_dst()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_TP_DST)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_tp_dst length is %d, should be 8" % _length)
-        obj.tp_port = struct.unpack_from('!H', buf, 4)[0]
-        obj.pad = list(struct.unpack_from('!2B', buf, 6))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_TP_DST)
+        _len = reader.read('!H')[0]
+        obj.tp_port = reader.read('!H')[0]
+        reader.skip(2)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.tp_port != other.tp_port: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -740,31 +684,25 @@
                 q.breakable()
                 q.text("tp_port = ");
                 q.text("%#x" % self.tp_port)
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 class set_tp_src(Action):
     type = const.OFPAT_SET_TP_SRC
 
-    def __init__(self, tp_port=None, pad=None):
+    def __init__(self, tp_port=None):
         if tp_port != None:
             self.tp_port = tp_port
         else:
             self.tp_port = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!H", self.tp_port))
-        packed.append(struct.pack("!2B", *self.pad))
+        packed.append('\x00' * 2)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -772,20 +710,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_tp_src()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_TP_SRC)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_tp_src length is %d, should be 8" % _length)
-        obj.tp_port = struct.unpack_from('!H', buf, 4)[0]
-        obj.pad = list(struct.unpack_from('!2B', buf, 6))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_TP_SRC)
+        _len = reader.read('!H')[0]
+        obj.tp_port = reader.read('!H')[0]
+        reader.skip(2)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.tp_port != other.tp_port: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -802,31 +740,25 @@
                 q.breakable()
                 q.text("tp_port = ");
                 q.text("%#x" % self.tp_port)
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 class set_vlan_pcp(Action):
     type = const.OFPAT_SET_VLAN_PCP
 
-    def __init__(self, vlan_pcp=None, pad=None):
+    def __init__(self, vlan_pcp=None):
         if vlan_pcp != None:
             self.vlan_pcp = vlan_pcp
         else:
             self.vlan_pcp = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!B", self.vlan_pcp))
-        packed.append(struct.pack("!3B", *self.pad))
+        packed.append('\x00' * 3)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -834,20 +766,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_vlan_pcp()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_VLAN_PCP)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_vlan_pcp length is %d, should be 8" % _length)
-        obj.vlan_pcp = struct.unpack_from('!B', buf, 4)[0]
-        obj.pad = list(struct.unpack_from('!3B', buf, 5))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_VLAN_PCP)
+        _len = reader.read('!H')[0]
+        obj.vlan_pcp = reader.read('!B')[0]
+        reader.skip(3)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.vlan_pcp != other.vlan_pcp: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -864,31 +796,25 @@
                 q.breakable()
                 q.text("vlan_pcp = ");
                 q.text("%#x" % self.vlan_pcp)
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 class set_vlan_vid(Action):
     type = const.OFPAT_SET_VLAN_VID
 
-    def __init__(self, vlan_vid=None, pad=None):
+    def __init__(self, vlan_vid=None):
         if vlan_vid != None:
             self.vlan_vid = vlan_vid
         else:
             self.vlan_vid = 0
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0]
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
         packed.append(struct.pack("!H", self.vlan_vid))
-        packed.append(struct.pack("!2B", *self.pad))
+        packed.append('\x00' * 2)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -896,20 +822,20 @@
     @staticmethod
     def unpack(buf):
         obj = set_vlan_vid()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_SET_VLAN_VID)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("set_vlan_vid length is %d, should be 8" % _length)
-        obj.vlan_vid = struct.unpack_from('!H', buf, 4)[0]
-        obj.pad = list(struct.unpack_from('!2B', buf, 6))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_SET_VLAN_VID)
+        _len = reader.read('!H')[0]
+        obj.vlan_vid = reader.read('!H')[0]
+        reader.skip(2)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
         if self.vlan_vid != other.vlan_vid: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -926,26 +852,20 @@
                 q.breakable()
                 q.text("vlan_vid = ");
                 q.text("%#x" % self.vlan_vid)
-                q.text(","); q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 class strip_vlan(Action):
     type = const.OFPAT_STRIP_VLAN
 
-    def __init__(self, pad=None):
-        if pad != None:
-            self.pad = pad
-        else:
-            self.pad = [0,0,0,0]
+    def __init__(self):
+        return
 
     def pack(self):
         packed = []
         packed.append(struct.pack("!H", self.type))
         packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
-        packed.append(struct.pack("!4B", *self.pad))
+        packed.append('\x00' * 4)
         length = sum([len(x) for x in packed])
         packed[1] = struct.pack("!H", length)
         return ''.join(packed)
@@ -953,18 +873,18 @@
     @staticmethod
     def unpack(buf):
         obj = strip_vlan()
-        type = struct.unpack_from('!H', buf, 0)[0]
-        assert(type == const.OFPAT_STRIP_VLAN)
-        _length = struct.unpack_from('!H', buf, 2)[0]
-        assert(_length == len(buf))
-        if _length != 8: raise loxi.ProtocolError("strip_vlan length is %d, should be 8" % _length)
-        obj.pad = list(struct.unpack_from('!4B', buf, 4))
+        if type(buf) == loxi.generic_util.OFReader:
+            reader = buf
+        else:
+            reader = loxi.generic_util.OFReader(buf)
+        _type = reader.read('!H')[0]
+        assert(_type == const.OFPAT_STRIP_VLAN)
+        _len = reader.read('!H')[0]
+        reader.skip(4)
         return obj
 
     def __eq__(self, other):
         if type(self) != type(other): return False
-        if self.type != other.type: return False
-        if self.pad != other.pad: return False
         return True
 
     def __ne__(self, other):
@@ -979,26 +899,22 @@
         with q.group():
             with q.indent(2):
                 q.breakable()
-                q.text("pad = ");
-                q.pp(self.pad)
             q.breakable()
         q.text('}')
 
 
-def parse_vendor(buf):
-    if len(buf) < 16:
-        raise loxi.ProtocolError("experimenter action too short")
+def parse_vendor(reader):
 
-    experimenter, = struct.unpack_from("!L", buf, 4)
+    experimenter, = reader.peek("!4xL")
     if experimenter == 0x005c16c7: # Big Switch Networks
-        subtype, = struct.unpack_from("!L", buf, 8)
+        subtype, = reader.peek("!8xL")
     elif experimenter == 0x00002320: # Nicira
-        subtype, = struct.unpack_from("!H", buf, 8)
+        subtype, = reader.peek("!8xH")
     else:
         raise loxi.ProtocolError("unexpected experimenter id %#x" % experimenter)
 
     if subtype in experimenter_parsers[experimenter]:
-        return experimenter_parsers[experimenter][subtype](buf)
+        return experimenter_parsers[experimenter][subtype](reader)
     else:
         raise loxi.ProtocolError("unexpected BSN experimenter subtype %#x" % subtype)