old_contents: # Copyright (C) 2013 Nippon Telegraph and Telephone Corporation.
  # Copyright (C) 2013 Isaku Yamahata <yamahata at private email ne jp>
  #
  # 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.
  
  from ryu.lib.packet import ethernet
  from ryu.lib.packet import vlan
  from ryu.ofproto import ether
  from ryu.topology import api as topo_api
  
  
  def may_add_vlan(packet, vlan_id):
      """
      :type packet: ryu.lib.packet.packet.Packet
      :param packet:
      :type vlan_id: int (0 <= vlan_id <= 4095) or None (= No VLAN)
      :param vlan_id:
      """
      if vlan_id is None:
          return
  
      e = packet.protocols[0]
      assert isinstance(e, ethernet.ethernet)
      v = vlan.vlan(0, 0, vlan_id, e.ethertype)
      e.ethertype = ether.ETH_TYPE_8021Q
      packet.add_protocol(v)
  
  
  def get_dp(app, dpid):
      """
      :type dpid: datapath id
      :param dpid:
      :rtype: ryu.controller.controller.Datapatyh
      :returns: datapath corresponding to dpid
      """
      switches = topo_api.get_switch(app, dpid)
      if not switches:
          return None
      assert len(switches) == 1
      return switches[0].dp
  
  
  def dp_packet_out(dp, port_no, data):
      # OF 1.2
      ofproto = dp.ofproto
      ofproto_parser = dp.ofproto_parser
      actions = [ofproto_parser.OFPActionOutput(port_no,
                                                ofproto.OFPCML_NO_BUFFER)]
      packet_out = ofproto_parser.OFPPacketOut(
          dp, 0xffffffff, ofproto.OFPP_CONTROLLER, actions, data)
      dp.send_msg(packet_out)
  
  
  def dp_flow_mod(dp, table, command, priority, match, instructions,
                  out_port=None):
      # OF 1.2
      ofproto = dp.ofproto
      ofproto_parser = dp.ofproto_parser
      if out_port is None:
          out_port = ofproto.OFPP_ANY
      flow_mod = ofproto_parser.OFPFlowMod(
          dp, 0, 0, table, command, 0, 0,
          priority, 0xffffffff, out_port, ofproto.OFPG_ANY,
          ofproto.OFPFF_CHECK_OVERLAP, match, instructions)
      dp.send_msg(flow_mod)
  
new_contents: # Copyright (C) 2013 Nippon Telegraph and Telephone Corporation.
  # Copyright (C) 2013 Isaku Yamahata <yamahata at private email ne jp>
  #
  # 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.
  
  from ryu.lib.packet import ethernet
  from ryu.lib.packet import vlan
  from ryu.ofproto import ether
  from ryu.topology import switches as topo_api
  
  
  def may_add_vlan(packet, vlan_id):
      """
      :type packet: ryu.lib.packet.packet.Packet
      :param packet:
      :type vlan_id: int (0 <= vlan_id <= 4095) or None (= No VLAN)
      :param vlan_id:
      """
      if vlan_id is None:
          return
  
      e = packet.protocols[0]
      assert isinstance(e, ethernet.ethernet)
      v = vlan.vlan(0, 0, vlan_id, e.ethertype)
      e.ethertype = ether.ETH_TYPE_8021Q
      packet.add_protocol(v)
  
  
  def get_dp(app, dpid):
      """
      :type dpid: datapath id
      :param dpid:
      :rtype: ryu.controller.controller.Datapatyh
      :returns: datapath corresponding to dpid
      """
      switches = topo_api.get_switch(app, dpid)
      if not switches:
          return None
      assert len(switches) == 1
      return switches[0].dp
  
  
  def dp_packet_out(dp, port_no, data):
      # OF 1.2
      ofproto = dp.ofproto
      ofproto_parser = dp.ofproto_parser
      actions = [ofproto_parser.OFPActionOutput(port_no,
                                                ofproto.OFPCML_NO_BUFFER)]
      packet_out = ofproto_parser.OFPPacketOut(
          dp, 0xffffffff, ofproto.OFPP_CONTROLLER, actions, data)
      dp.send_msg(packet_out)
  
  
  def dp_flow_mod(dp, table, command, priority, match, instructions,
                  out_port=None):
      # OF 1.2
      ofproto = dp.ofproto
      ofproto_parser = dp.ofproto_parser
      if out_port is None:
          out_port = ofproto.OFPP_ANY
      flow_mod = ofproto_parser.OFPFlowMod(
          dp, 0, 0, table, command, 0, 0,
          priority, 0xffffffff, out_port, ofproto.OFPG_ANY,
          ofproto.OFPFF_CHECK_OVERLAP, match, instructions)
      dp.send_msg(flow_mod)
  
subject: fix vrrp utils