packet.bgp: parse/serialize ROUTE REFRESH capability

also, provide the fallback "unknown" capablity class.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/lib/packet/bgp.py

@@ -192,7 +192,7 @@ class _OptParam(StringifyMixin, _TypeDisp, _Value):
         value = bytes(rest[:length])
         rest = rest[length:]
         subcls = cls._lookup_type(type_)
-        kwargs = subcls.parse_value(value)
+        kwargs, subcls = subcls.parse_value(value)
         return subcls(type_=type_, length=length, **kwargs), rest
 
     def serialize(self):
@@ -211,22 +211,27 @@ class BGPOptParamUnknown(_OptParam):
     def parse_value(cls, buf):
         return {
             'value': buf
-        }
+        }, cls
 
     def serialize_value(self):
         return self.value
 
 
 @_OptParam.register_type(BGP_OPT_CAPABILITY)
-class BGPOptParamCapability(_OptParam):
+class _OptParamCapability(_OptParam, _TypeDisp):
     _CAP_HDR_PACK_STR = '!BB'
 
-    def __init__(self, cap_code, cap_value, cap_length=None,
+    def __init__(self, cap_code=None, cap_value=None, cap_length=None,
                  type_=None, length=None):
-        super(BGPOptParamCapability, self).__init__(type_=type_, length=length)
+        super(_OptParamCapability, self).__init__(type_=BGP_OPT_CAPABILITY,
+                                                  length=length)
+        if cap_code is None:
+            cap_code = self._rev_lookup_type(self.__class__)
         self.cap_code = cap_code
-        self.cap_length = cap_length
-        self.cap_value = cap_value
+        if not cap_value is None:
+            self.cap_value = cap_value
+        if not cap_length is None:
+            self.cap_length = cap_length
 
     @classmethod
     def parse_value(cls, buf):
@@ -236,13 +241,14 @@ class BGPOptParamCapability(_OptParam):
         kwargs = {
             'cap_code': code,
             'cap_length': length,
-            'cap_value': value,
         }
-        return kwargs
+        subcls = cls._lookup_type(code)
+        kwargs.update(subcls.parse_cap_value(value))
+        return kwargs, subcls
 
     def serialize_value(self):
         # fixup
-        cap_value = self.cap_value
+        cap_value = self.serialize_cap_value()
         self.cap_length = len(cap_value)
 
         buf = bytearray()
@@ -251,6 +257,26 @@ class BGPOptParamCapability(_OptParam):
         return buf + cap_value
 
 
+@_OptParamCapability.register_unknown_type()
+class BGPOptParamCapabilityUnknown(_OptParamCapability):
+    @classmethod
+    def parse_cap_value(cls, buf):
+        return {'cap_value': buf}
+
+    def serialize_cap_value(self):
+        return self.cap_value
+
+
+@_OptParamCapability.register_type(BGP_CAP_ROUTE_REFRESH)
+class BGPOptParamCapabilityRouteRefresh(_OptParamCapability):
+    @classmethod
+    def parse_cap_value(cls, buf):
+        return {}
+
+    def serialize_cap_value(self):
+        return bytearray()
+
+
 class BGPWithdrawnRoute(_IPAddrPrefix):
     pass
 

ryu/tests/unit/packet/test_bgp.py

@@ -42,7 +42,9 @@ class Test_bgp(unittest.TestCase):
         eq_(rest, '')
 
     def test_open2(self):
-        opt_param = [bgp.BGPOptParamCapability(cap_code=200, cap_value='hoge'),
+        opt_param = [bgp.BGPOptParamCapabilityUnknown(cap_code=200,
+                                                      cap_value='hoge'),
+                     bgp.BGPOptParamCapabilityRouteRefresh(),
                      bgp.BGPOptParamUnknown(type_=99, value='fuga')]
         msg = bgp.BGPOpen(my_as=30000, bgp_identifier='192.0.2.2',
                           opt_param=opt_param)