261 lines
10 KiB
Python
261 lines
10 KiB
Python
from ryu.base import app_manager
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from ryu.controller import ofp_event
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from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
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from ryu.controller.handler import set_ev_cls
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from ryu.ofproto import ofproto_v1_3
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from ryu.lib.packet import packet
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from ryu.lib.packet import ethernet
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from ryu.lib.packet import ether_types
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from ryu.lib.packet import ipv4
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from ryu.lib.packet import icmp
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from ryu.lib.packet.arp import arp
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from ryu.lib.packet.packet import Packet
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class L3Switch(app_manager.RyuApp):
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OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
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IP_ADDR = "10.0.0.254"
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MAC_ADDR = "52:00:00:00:00:01"
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def __init__(self, *args, **kwargs):
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super(L3Switch, self).__init__(*args, **kwargs)
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self.mac_to_port = {}
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self.ip_to_mac = {}
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@set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
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def switch_features_handler(self, ev):
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datapath = ev.msg.datapath
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ofproto = datapath.ofproto
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parser = datapath.ofproto_parser
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# install table-miss flow entry
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#
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# We specify NO BUFFER to max_len of the output action due to
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# OVS bug. At this moment, if we specify a lesser number, e.g.,
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# 128, OVS will send Packet-In with invalid buffer_id and
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# truncated packet data. In that case, we cannot output packets
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# correctly. The bug has been fixed in OVS v2.1.0.
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match = parser.OFPMatch()
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actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
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ofproto.OFPCML_NO_BUFFER)]
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self.add_flow(datapath, 0, match, actions)
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def add_flow(self, datapath, priority, match, actions, buffer_id=None):
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ofproto = datapath.ofproto
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parser = datapath.ofproto_parser
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inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
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actions)]
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if buffer_id:
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mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id,
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priority=priority, match=match,
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instructions=inst)
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else:
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mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
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match=match, instructions=inst)
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datapath.send_msg(mod)
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def send_packet(self, datapath, port, pkt, buffer_id=None):
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ofproto = datapath.ofproto
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parser = datapath.ofproto_parser
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pkt.serialize()
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self.logger.info("packet-out %s" % (pkt,))
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data = pkt.data
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actions = [parser.OFPActionOutput(port=port)]
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if buffer_id:
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out = parser.OFPPacketOut(datapath=datapath,
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buffer_id=buffer_id,
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in_port=ofproto.OFPP_CONTROLLER,
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actions=actions,
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data=data)
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else:
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out = parser.OFPPacketOut(datapath=datapath,
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buffer_id=ofproto.OFP_NO_BUFFER,
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in_port=ofproto.OFPP_CONTROLLER,
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actions=actions,
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data=data)
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datapath.send_msg(out)
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def do_arp(self, datapath, packet, frame, inPort):
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dpid = datapath.id
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ofproto = datapath.ofproto
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parser = datapath.ofproto_parser
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arpPacket = packet.get_protocol(arp)
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if arpPacket.opcode == 1 :
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# arp request
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arp_dstIp = arpPacket.dst_ip
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self.logger.info('received ARP Request %s => %s (port%d)'%(frame.src, frame.dst, inPort))
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if arp_dstIp == self.IP_ADDR:
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# this switch was requested
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opcode = 2
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srcMAC = self.MAC_ADDR
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srcIP = self.IP_ADDR
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dstMAC = frame.src
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dstIP = arpPacket.src_ip
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outPort = inPort
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# learn mac 2 port mapping
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self.mac_to_port[dpid][dstMAC] = inPort
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# learn ip 2 mac mapping
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self.ip_to_mac[dpid][dstIP] = dstMAC
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self.logger.info("send ARP reply %s => %s (port%d)" %(srcMAC, dstMAC, outPort))
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else:
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if arpPacket.dst_ip in self.ip_to_mac[dpid]:
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# optimization: the switch already knows the mapping and can answer the request
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opcode = 2
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srcMAC = self.ip_to_mac[dpid][arpPacket.dst_ip]
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srcIP = arpPacket.dst_ip
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dstMAC = frame.src
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dstIP = arpPacket.src_ip
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outPort = self.mac_to_port[dpid][dstMAC]
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self.logger.info("optimization: answer ARP request %s => %s (port%d)" %(srcMAC, dstMAC, outPort))
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else:
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# forward arp request
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opcode = 1
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srcMAC = frame.src
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srcIP = arpPacket.src_ip
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dstMAC = frame.dst
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dstIP = arpPacket.dst_ip
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outPort = ofproto.OFPP_FLOOD
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# learn mac 2 port mapping
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self.mac_to_port[dpid][srcMAC] = inPort
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# learn ip 2 mac mapping
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self.ip_to_mac[dpid][srcIP] = srcMAC
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self.logger.info("froward ARP request %s => %s (port%d)" %(srcMAC, dstMAC, outPort))
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elif arpPacket.opcode == 2 :
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opcode = 2
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#arp reply
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# forward arp reply
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srcMAC = frame.src
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srcIP = arpPacket.src_ip
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dstMAC = frame.dst
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dstIP = arpPacket.dst_ip
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outPort = self.mac_to_port[dpid][dstMAC]
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# learn mac 2 port mapping
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self.mac_to_port[dpid][srcMAC] = inPort
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# learn ip 2 mac mapping
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self.ip_to_mac[dpid][srcIP] = srcMAC
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self.logger.debug('forward ARP reply %s => %s (port%d)'%(frame.src ,frame.dst, inPort))
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self.send_arp(datapath, opcode, srcMAC, srcIP, dstMAC, dstIP, outPort)
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def send_arp(self, datapath, opcode, srcMac, srcIp, dstMac, dstIp, outPort):
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if opcode == 1:
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targetMac = "FF:FF:FF:FF:FF:FF"
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targetIp = dstIp
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elif opcode == 2:
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targetMac = dstMac
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targetIp = dstIp
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e = ethernet.ethernet(dstMac, srcMac, ether_types.ETH_TYPE_ARP)
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a = arp(1, 0x0800, 6, 4, opcode, srcMac, srcIp, targetMac, targetIp)
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p = Packet()
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p.add_protocol(e)
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p.add_protocol(a)
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self.send_packet(datapath, outPort, p)
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def do_icmp(self, datapath, port, pkt_ethernet, pkt_ipv4, pkt_icmp):
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if pkt_icmp.type != icmp.ICMP_ECHO_REQUEST:
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return
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pkt = packet.Packet()
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pkt.add_protocol(ethernet.ethernet(ethertype=pkt_ethernet.ethertype,
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dst=pkt_ethernet.src,
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src=self.MAC_ADDR))
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pkt.add_protocol(ipv4.ipv4(dst=pkt_ipv4.src,
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src=self.IP_ADDR,
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proto=pkt_ipv4.proto))
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pkt.add_protocol(icmp.icmp(type_=icmp.ICMP_ECHO_REPLY,
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code=icmp.ICMP_ECHO_REPLY_CODE,
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csum=0,
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data=pkt_icmp.data))
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self.logger.info("do icmp: %s" %(pkt,))
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self.send_packet(datapath, port, pkt)
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def do_l2_switch(self, datapath, dpid, packet, frame, in_port, buffer_id=None):
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ofproto = datapath.ofproto
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parser = datapath.ofproto_parser
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if frame.dst in self.mac_to_port[dpid]:
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out_port = self.mac_to_port[dpid][frame.dst]
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else:
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out_port = ofproto.OFPP_FLOOD
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actions = [parser.OFPActionOutput(out_port)]
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# install a flow to avoid packet_in next time
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if out_port != ofproto.OFPP_FLOOD:
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match = parser.OFPMatch(in_port=in_port, eth_dst=frame.dst)
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# verify if we have a valid buffer_id, if yes avoid to send both
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# flow_mod & packet_out
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if buffer_id != ofproto.OFP_NO_BUFFER:
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self.add_flow(datapath, 1, match, actions, buffer_id)
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return
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else:
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self.add_flow(datapath, 1, match, actions)
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data = None
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if buffer_id == ofproto.OFP_NO_BUFFER:
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data = packet.data
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out = parser.OFPPacketOut(datapath=datapath, buffer_id=buffer_id,
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in_port=in_port, actions=actions, data=data)
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datapath.send_msg(out)
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@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
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def _packet_in_handler(self, ev):
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# If you hit this you might want to increase
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# the "miss_send_length" of your switch
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if ev.msg.msg_len < ev.msg.total_len:
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self.logger.debug("packet truncated: only %s of %s bytes",
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ev.msg.msg_len, ev.msg.total_len)
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msg = ev.msg
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datapath = msg.datapath
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ofproto = datapath.ofproto
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parser = datapath.ofproto_parser
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in_port = msg.match['in_port']
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pkt = packet.Packet(msg.data)
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eth = pkt.get_protocols(ethernet.ethernet)[0]
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if eth.ethertype == ether_types.ETH_TYPE_LLDP:
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# ignore lldp packet
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return
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dst = eth.dst
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src = eth.src
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dpid = datapath.id
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self.mac_to_port.setdefault(dpid, {})
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self.ip_to_mac.setdefault(dpid, {})
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self.logger.info("packet in dpid: %s, src: %s, dest: %s, in_port: %s", dpid, src, dst, in_port)
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#learn mac to port mapping
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if src not in self.mac_to_port[dpid]:
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self.mac_to_port[dpid][src] = in_port
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if eth.ethertype == ether_types.ETH_TYPE_ARP:
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self.do_arp(datapath, pkt, eth, in_port)
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return
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if eth.ethertype == ether_types.ETH_TYPE_IP:
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ipv4_pkt = pkt.get_protocol(ipv4.ipv4)
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#check if packet is for this switch
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if ipv4_pkt.dst == self.IP_ADDR:
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icmp_pkt = pkt.get_protocol(icmp.icmp)
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if icmp_pkt:
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self.do_icmp(datapath, in_port, eth, ipv4_pkt, icmp_pkt)
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else:
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# here we would forward the packet into other subnets
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pass
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# packet is not for this switch, so do l2 switching
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if dst != self.MAC_ADDR:
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self.do_l2_switch(datapath, dpid, pkt, eth, in_port, msg.buffer_id)
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return
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return
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