""" Simple Ryu Application to demonstrate OpenFlow switch blocking host until it send a "magic" packet (UDP containing "xyzzy", eg, DNS) (OpenFlow 1.3 only, simple single table example with only flooding) For details see: http://www.naos.co.nz/talks/seize-control-with-ryu/ Written by Ewen McNeill , 2014-09-09 Copyright (c) 2014 Naos Ltd All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """ from ryu.base import app_manager from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER from ryu.controller.handler import set_ev_cls from ryu.ofproto import ofproto_v1_3, ether, inet from ryu.lib.packet import packet, ethernet class KiwiPycon(app_manager.RyuApp): # Tell Ryu to only accept OpenFlow 1.3 OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] # Internal constants for ports, priority, etc MAGIC_COOKIE = bytearray(b"xyzzy") (PORT_H1, PORT_H2) = (1,2) (PRI_LOW, PRI_MID, PRI_HIGH) = (20, 30, 40) # Minimal __init__ def __init__(self, *args, **kwargs): super(KiwiPycon, self).__init__(*args, **kwargs) # Helper to prepare format flow add messages def add_flow(self, dp, priority, match, actions): ofp = dp.ofproto parser = dp.ofproto_parser inst = [] if actions: inst = [parser.OFPInstructionActions( ofp.OFPIT_APPLY_ACTIONS, actions)] mod = parser.OFPFlowMod(datapath=dp, table_id=0, priority=priority, match=match, instructions=inst) dp.set_xid(mod) # Preallocate transaction ID dp.send_msg(mod) # Helper to delete all flows (ie, reset to default) # (No filtering on delete, so deletes everything in table 0) def del_flows(self, dp): ofp = dp.ofproto parser = dp.ofproto_parser wildcard_match = parser.OFPMatch() instructions = [] mod = parser.OFPFlowMod(datapath=dp, table_id=0, command=ofp.OFPFC_DELETE, out_port=ofp.OFPP_ANY, out_group=ofp.OFPP_ANY, match=wildcard_match, instructions=instructions) dp.send_msg(mod) # Add flow to flood all arp packets, so ARP works def flood_all_arp(self, dp): ofp = dp.ofproto parser = dp.ofproto_parser self.logger.info("Permitting ARP, by flooding") match = parser.OFPMatch(eth_type = ether.ETH_TYPE_ARP) actions = [parser.OFPActionOutput(ofp.OFPP_FLOOD, ofp.OFPCML_NO_BUFFER)] self.add_flow(dp, KiwiPycon.PRI_MID, match, actions) # Add override (high priority) to flood traffic from MAC def permit_traffic_from_mac(self, dp, src_mac): ofp = dp.ofproto parser = dp.ofproto_parser self.logger.info("Permitting traffic from %s" % src_mac) match = parser.OFPMatch(eth_src = src_mac) actions = [parser.OFPActionOutput(ofp.OFPP_FLOOD, ofp.OFPCML_NO_BUFFER)] self.add_flow(dp, KiwiPycon.PRI_HIGH, match, actions) # Add (low priority) defaults that block traffic) def block_traffic_by_default(self, dp): ofp = dp.ofproto parser = dp.ofproto_parser self.logger.info("Clearing existing flows") self.del_flows(dp) self.logger.info("Blocking traffic from h1's port by default") match = parser.OFPMatch(in_port = KiwiPycon.PORT_H1) actions = None self.add_flow(dp, KiwiPycon.PRI_LOW, match, actions) self.logger.info("Allowing traffic from h2's port by default") match = parser.OFPMatch(in_port = KiwiPycon.PORT_H2) actions = [parser.OFPActionOutput(ofp.OFPP_FLOOD, ofp.OFPCML_NO_BUFFER)] self.add_flow(dp, KiwiPycon.PRI_LOW, match, actions) # Ask switch to send us UDP packets from host 1 def add_notify_on_udp_from_host_1(self, dp): ofp = dp.ofproto parser = dp.ofproto_parser self.logger.info("Request notify on UDP from h1") match = parser.OFPMatch(in_port = KiwiPycon.PORT_H1, eth_type = ether.ETH_TYPE_IP, ip_proto = inet.IPPROTO_UDP) actions = [parser.OFPActionOutput(ofp.OFPP_CONTROLLER, ofp.OFPCML_NO_BUFFER)] self.add_flow(dp, KiwiPycon.PRI_MID, match, actions) @set_ev_cls(ofp_event.EventOFPStateChange, MAIN_DISPATCHER) def new_connection(self, ev): dp = ev.datapath self.logger.info("Switch connected (id=%s)" % dp.id) self.block_traffic_by_default(dp) self.flood_all_arp(dp) self.add_notify_on_udp_from_host_1(dp) @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def handle_packet(self, ev): pkt = packet.Packet(ev.msg.data) eth = pkt.get_protocol(ethernet.ethernet) self.logger.info("UDP received from %s" % eth.src) if ev.msg.data.find(KiwiPycon.MAGIC_COOKIE) >= 0: self.logger.info("Magic cookie found from %s" % eth.src) self.permit_traffic_from_mac(ev.msg.datapath, eth.src)