Decoration Based PacketIn Filter

It is noisy when packets goes into a handler of EventOFPPacketIn indiscriminately. Then, we introduce API which filters a packet. API is decorator and a filtering algorithem is pluggable.

Signed-off-by: Satoshi Kobayashi <satoshi-k@stratosphere.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/lib/ofp_pktinfilter.py

@@ -0,0 +1,57 @@
+# Copyright (C) 2013 Stratosphere 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.
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+import logging
+from abc import ABCMeta, abstractmethod
+
+from ryu.lib.packet import packet
+
+LOG = logging.getLogger(__name__)
+
+
+def packet_in_filter(cls, args=None):
+    def _packet_in_filter(packet_in_handler):
+        def __packet_in_filter(self, ev):
+            pkt = packet.Packet(ev.msg.data)
+            if not packet_in_handler.pkt_in_filter.filter(pkt):
+                LOG.debug('The packet is discarded by %s: %s' % (cls, pkt))
+                return
+            return packet_in_handler(self, ev)
+        pkt_in_filter = cls(args)
+        packet_in_handler.pkt_in_filter = pkt_in_filter
+        return __packet_in_filter
+    return _packet_in_filter
+
+
+class PacketInFilterBase(object):
+    __metaclass__ = ABCMeta
+
+    def __init__(self, args):
+        self.args = args
+
+    @abstractmethod
+    def filter(self, pkt):
+        pass
+
+
+class RequiredTypeFilter(PacketInFilterBase):
+
+    def filter(self, pkt):
+        required_types = self.args.get('types') or []
+        for required_type in required_types:
+            if not pkt.get_protocol(required_type):
+                return False
+        return True

ryu/tests/unit/lib/test_ofp_pktinfilter.py

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+# Copyright (C) 2013 Stratosphere 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.
+
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+import unittest
+import logging
+
+from nose.tools import *
+
+from ryu.base import app_manager
+from ryu.controller import ofp_event
+from ryu.controller.handler import (
+    set_ev_cls,
+    MAIN_DISPATCHER,
+)
+from ryu.lib.packet import vlan, ethernet, ipv4
+from ryu.lib.ofp_pktinfilter import packet_in_filter, RequiredTypeFilter
+from ryu.lib import mac
+from ryu.ofproto import ether, ofproto_v1_3, ofproto_v1_3_parser
+
+
+LOG = logging.getLogger('test_pktinfilter')
+
+
+class _Datapath(object):
+    ofproto = ofproto_v1_3
+    ofproto_parser = ofproto_v1_3_parser
+
+
+class _PacketInFilterApp(app_manager.RyuApp):
+
+    def __init__(self, *args, **kwargs):
+        super(_PacketInFilterApp, self).__init__(*args, **kwargs)
+
+    @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
+    @packet_in_filter(RequiredTypeFilter, {'types': [
+        vlan.vlan,
+    ]})
+    def packet_in_handler(self, ev):
+        return True
+
+
+class Test_packet_in_filter(unittest.TestCase):
+
+    """ Test case for pktinfilter
+    """
+
+    def setUp(self):
+        self.app = _PacketInFilterApp()
+
+    def tearDown(self):
+        pass
+
+    def test_pkt_in_filter_pass(self):
+        datapath = _Datapath()
+        e = ethernet.ethernet(mac.BROADCAST_STR,
+                              mac.BROADCAST_STR,
+                              ether.ETH_TYPE_8021Q)
+        v = vlan.vlan()
+        i = ipv4.ipv4()
+        pkt = (e / v / i)
+        pkt.serialize()
+        pkt_in = ofproto_v1_3_parser.OFPPacketIn(datapath,
+                                                 data=buffer(pkt.data))
+        ev = ofp_event.EventOFPPacketIn(pkt_in)
+        ok_(self.app.packet_in_handler(ev))
+
+    def test_pkt_in_filter_discard(self):
+        datapath = _Datapath()
+        e = ethernet.ethernet(mac.BROADCAST_STR,
+                              mac.BROADCAST_STR,
+                              ether.ETH_TYPE_IP)
+        i = ipv4.ipv4()
+        pkt = (e / i)
+        pkt.serialize()
+        pkt_in = ofproto_v1_3_parser.OFPPacketIn(datapath,
+                                                 data=buffer(pkt.data))
+        ev = ofp_event.EventOFPPacketIn(pkt_in)
+        ok_(not self.app.packet_in_handler(ev))
+
+    def test_pkt_in_filter_truncated(self):
+        datapath = _Datapath()
+        truncated_data = buffer('')
+        pkt_in = ofproto_v1_3_parser.OFPPacketIn(datapath,
+                                                 data=truncated_data)
+        ev = ofp_event.EventOFPPacketIn(pkt_in)
+        ok_(not self.app.packet_in_handler(ev))