switch controller for lab

sample_code_modified.py

from ryu.base import app_manager
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_3
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import ether_types
from ryu.lib.packet import arp
from ryu.lib.packet import ipv4
from ryu.lib.packet import tcp
from ryu.lib.packet import udp
from ryu.lib.packet import icmp

class SimpleSwitch13(app_manager.RyuApp):
    OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
    
    def __init__(self, *args, **kwargs):
        
        super(SimpleSwitch13, self).__init__(*args, **kwargs)
    
    @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
    def switch_features_handler(self, ev):
        datapath = ev.msg.datapath
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser
        match = parser.OFPMatch()
        actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
        ofproto.OFPCML_NO_BUFFER)]
        self.add_flow(datapath, 0, match, actions)

    def add_flow(self, datapath, priority, match, actions):
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser
        inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
        actions)]
        mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
        match=match, instructions=inst)
        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
        in_port = msg.match['in_port']
        pkt = packet.Packet(msg.data)
        eth = pkt.get_protocol(ethernet.ethernet)
        dst = eth.dst # MAC
        
        src = eth.src # MAC
        pkt_arp = pkt.get_protocol(arp.arp)
        pkt_ipv4 = pkt.get_protocol(ipv4.ipv4)
        pkt_icmp = pkt.get_protocol(icmp.icmp)
        pkt_tcp = pkt.get_protocol(tcp.tcp)
        pkt_udp = pkt.get_protocol(udp.udp)
        
        # ARP
        if pkt_arp:
            # dst_ip, dst_mac=ffffff
            mypkt = packet.Packet()
            mypkt.add_protocol(ethernet.ethernet(
            src=根据 dst_ip 得到的 mac,
            dst=src))
            mypkt.add_protocol(arp.arp(src_mac=根据 dst_ip 得到的 mac, dst_mac=, src_ip=, dst_ip=, opcode=arp.ARP_REPLY))
            self._send_msg(mypkt)
        
        # IPV4
        elif pkt_ipv4:
            # ICMP
            if pkt_icmp:
                # calc out port
                out_port =
                # add flow
                match = parser.OFPMatch()
                actions = [parser.OFPActionOutput(port=out_port)]
                self.add_flow(datapath, 1, match, actions)
                # send packet
                self._send_msg(datapath, pkt, out_port)
        
        # TCP
            elif pkt_tcp:
            # HTTP RST
                if pkt_tcp.dst_port == 80 and (HOST2 or HOST4):
                # generate an HTTP RST packet
                # send packet
        # NON-TCP HTTP
        else:
            # calc out port
            # add flow
            # send packet
            # add http flow
        
        # UDP
        elif pkt_udp:
            if HOST1 or HOST4:
            # add drop flow
            else:
            # calc out port
            # add flow
            # send packet
 
    def _send_msg(self, switch, pkt, out_port):
    return