simple_switch.py

# Copyright (C) 2011 Nippon Telegraph and Telephone Corporation.
#
# 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.

"""
An OpenFlow 1.0 L2 learning switch implementation.
"""

import logging
import struct

from ryu.base import app_manager
from ryu.controller import mac_to_port
from ryu.controller import ofp_event
from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_0, ether
from ryu.lib.mac import haddr_to_bin
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet, ipv4, ipv6, tcp, udp


class SimpleSwitch(app_manager.RyuApp):
    OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION]

    def __init__(self, *args, **kwargs):
        super(SimpleSwitch, self).__init__(*args, **kwargs)
        self.mac_to_port = {}


    def add_flow(self, datapath, in_port, dst, action):
        self.logger.info('New host {} at port {}'.format(dst, in_port))
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser
        # Prioritise UDP port 1337 traffic
        actions = [parser.OFPActionVlanPcp(7),
                   action]
        match = parser.OFPMatch(in_port=in_port,
                                dl_type = 0x800,
                                nw_proto = 0x11,
                                tp_dst = 1337)

        mod = parser.OFPFlowMod(datapath=datapath,
                                match=match,
                                cookie=0,
                                command=ofproto.OFPFC_ADD,
                                idle_timeout=20,
                                hard_timeout=0,
                                priority=100,
                                flags=ofproto.OFPFF_SEND_FLOW_REM,
                                actions=actions)
        datapath.send_msg(mod)
        # Normal traffic
        actions = [parser.OFPActionVlanPcp(1),
                   action]
        match = parser.OFPMatch(in_port=in_port,
                                dl_type = 0x800,
                                nw_proto = 0x11,
                                tp_dst = 4242)
                                #dl_type = 0x01)
                                #dl_dst=haddr_to_bin(dst))
        mod = parser.OFPFlowMod(datapath=datapath,
                                match=match,
                                cookie=0,
                                command=ofproto.OFPFC_ADD,
                                idle_timeout=20,
                                hard_timeout=0,
                                priority=50,
                                flags=ofproto.OFPFF_SEND_FLOW_REM,
                                actions=actions)
        datapath.send_msg(mod)
        
    @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
    def _packet_in_handler(self, ev):
        msg = ev.msg
        datapath = msg.datapath
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser

        pkt = packet.Packet(msg.data)
        eth = pkt.get_protocol(ethernet.ethernet)

        dst = eth.dst
        src = eth.src

        dpid = datapath.id
        self.mac_to_port.setdefault(dpid, {})
            

        # learn a mac address to avoid FLOOD next time.
        self.mac_to_port[dpid][src] = msg.in_port

        if dst in self.mac_to_port[dpid]:
            out_port = self.mac_to_port[dpid][dst]
        else:
            out_port = ofproto.OFPP_FLOOD

        action = parser.OFPActionOutput(out_port)

        # install a flow to avoid packet_in next time
        if out_port != ofproto.OFPP_FLOOD:
            self.add_flow(datapath, msg.in_port, dst, action)

        data = None
        if msg.buffer_id == ofproto.OFP_NO_BUFFER:
            data = msg.data

        out = datapath.ofproto_parser.OFPPacketOut(
            datapath=datapath, buffer_id=msg.buffer_id, in_port=msg.in_port,
            actions=[action], data=data)
        datapath.send_msg(out)

    @set_ev_cls(ofp_event.EventOFPPortStatus, MAIN_DISPATCHER)
    def _port_status_handler(self, ev):
        msg = ev.msg
        reason = msg.reason
        port_no = msg.desc.port_no

        ofproto = msg.datapath.ofproto
        if reason == ofproto.OFPPR_ADD:
            self.logger.info("port added %s", port_no)
        elif reason == ofproto.OFPPR_DELETE:
            self.logger.info("port deleted %s", port_no)
        elif reason == ofproto.OFPPR_MODIFY:
            self.logger.info("port modified %s", port_no)
        else:
            self.logger.info("Illeagal port state %s %s", port_no, reason)