of14: Add OFPPropCommonExperimenter4ByteData

There are several different experimenter properties in OF1.4 which
are identical in structure. They have experimenter, exp_type
and data fields. The data field is an array of 4-byte words.

This patch adds OFPPropCommonExperimenter4ByteData which provides
a parser and serializer for such properties and can be inherited
by a subclass which implements one of the properties.

This patch also uses OFPPropCommonExperimenter4ByteData to implement
queue desc properties and table mod properties.

It is planned to use OFPPropCommonExperimenter4ByteData to implement
role properties.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/ofproto/ofproto_v1_4_parser.py

@@ -788,6 +788,60 @@ class OFPPropBase(StringifyMixin):
         return prop, rest
 
 
+class OFPPropCommonExperimenter4ByteData(StringifyMixin):
+    _DATA_ELEMENT_PACK_STR = '!I'
+    _PACK_STR = '!HHII'
+
+    def __init__(self, type_=None, length=None, experimenter=None,
+                 exp_type=None, data=None):
+        self.type = type_
+        self.length = length
+        self.experimenter = experimenter
+        self.exp_type = exp_type
+        self.data = data
+
+    @classmethod
+    def parser(cls, buf):
+        exp = cls()
+        (exp.type, exp.length, exp.experimenter,
+         exp.exp_type) = struct.unpack_from(
+            ofproto.OFP_TABLE_MOD_PROP_EXPERIMENTER_PACK_STR, buf, 0)
+
+        # Parse trailing data, a list of 4-byte words
+        exp.data = []
+        pack_size = struct.calcsize(cls._DATA_ELEMENT_PACK_STR)
+        offset = ofproto.OFP_TABLE_MOD_PROP_EXPERIMENTER_SIZE
+        while offset < exp.length:
+            (word,) = struct.unpack_from(cls._DATA_ELEMENT_PACK_STR,
+                                         buf, offset)
+            exp.data.append(word)
+            offset += pack_size
+
+        return exp
+
+    def serialize(self):
+        data_buf = bytearray()
+        if len(self.data):
+            ofproto_parser.msg_pack_into('!%dI' % len(self.data),
+                                         data_buf, 0, *self.data)
+
+        #fixup
+        self.length = struct.calcsize(self._PACK_STR)
+        self.length += len(data_buf)
+
+        buf = bytearray()
+        msg_pack_into(self._PACK_STR, buf,
+                      0, self.type, self.length, self.experimenter,
+                      self.exp_type)
+        buf += data_buf
+
+        # Pad
+        pad_len = utils.round_up(self.length, 8) - self.length
+        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, len(buf))
+
+        return buf
+
+
 class OFPPortProp(OFPPropBase):
     _TYPES = {}
 
@@ -873,57 +927,8 @@ class OFPTableModPropVacancy(StringifyMixin):
 
 
 @OFPTableModProp.register_type(ofproto.OFPTMPT_EXPERIMENTER)
-class OFPTableModPropExperimenter(StringifyMixin):
-    _DATA_ELEMENT_PACK_STR = '!I'
-
-    def __init__(self, type_=None, length=None, experimenter=None,
-                 exp_type=None, data=None):
-        self.type = type_
-        self.length = length
-        self.experimenter = experimenter
-        self.exp_type = exp_type
-        self.data = data
-
-    @classmethod
-    def parser(cls, buf):
-        exp = cls()
-        (exp.type, exp.length, exp.experimenter,
-         exp.exp_type) = struct.unpack_from(
-            ofproto.OFP_TABLE_MOD_PROP_EXPERIMENTER_PACK_STR, buf, 0)
-
-        # Parse trailing data, a list of 4-byte words
-        exp.data = []
-        pack_size = struct.calcsize(cls._DATA_ELEMENT_PACK_STR)
-        offset = ofproto.OFP_TABLE_MOD_PROP_EXPERIMENTER_SIZE
-        while offset < exp.length:
-            (word,) = struct.unpack_from(cls._DATA_ELEMENT_PACK_STR,
-                                         buf, offset)
-            exp.data.append(word)
-            offset += pack_size
-
-        return exp
-
-    def serialize(self):
-        data_buf = bytearray()
-        if len(self.data):
-            ofproto_parser.msg_pack_into('!%dI' % len(self.data),
-                                         data_buf, 0, *self.data)
-
-        #fixup
-        self.length = ofproto.OFP_TABLE_MOD_PROP_EXPERIMENTER_SIZE
-        self.length += len(data_buf)
-
-        buf = bytearray()
-        msg_pack_into(ofproto.OFP_TABLE_MOD_PROP_EXPERIMENTER_PACK_STR, buf,
-                      0, self.type, self.length, self.experimenter,
-                      self.exp_type)
-        buf += data_buf
-
-        # Pad
-        pad_len = utils.round_up(self.length, 8) - self.length
-        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, len(buf))
-
-        return buf
+class OFPTableModPropExperimenter(OFPPropCommonExperimenter4ByteData):
+    pass
 
 
 class OFPQueueDescProp(OFPPropBase):
@@ -961,35 +966,8 @@ class OFPQueueDescPropMaxRate(StringifyMixin):
 
 
 @OFPQueueDescProp.register_type(ofproto.OFPQDPT_EXPERIMENTER)
-class OFPQueueDescPropExperimenter(StringifyMixin):
-    _DATA_ELEMENT_PACK_STR = '!I'
-
-    def __init__(self, type_=None, length=None, experimenter=None,
-                 exp_type=None, data=None):
-        self.type = type_
-        self.length = length
-        self.experimenter = experimenter
-        self.exp_type = exp_type
-        self.data = data
-
-    @classmethod
-    def parser(cls, buf):
-        exp = cls()
-        (exp.type, exp.length, exp.experimenter,
-         exp.exp_type) = struct.unpack_from(
-            ofproto.OFP_QUEUE_DESC_PROP_EXPERIMENTER_PACK_STR, buf, 0)
-
-        # Parse trailing data, a list of 4-byte words
-        exp.data = []
-        pack_size = struct.calcsize(cls._DATA_ELEMENT_PACK_STR)
-        offset = ofproto.OFP_QUEUE_DESC_PROP_EXPERIMENTER_SIZE
-        while offset < exp.length:
-            (word,) = struct.unpack_from(cls._DATA_ELEMENT_PACK_STR,
-                                         buf, offset)
-            exp.data.append(word)
-            offset += pack_size
-
-        return exp
+class OFPQueueDescPropExperimenter(OFPPropCommonExperimenter4ByteData):
+    pass
 
 
 class OFPMatchField(StringifyMixin):