RYU Controller with ARP Loop (Python API Mininet)

Question

TOpology Loop

I have a problem with the ARP loop. I have attached my python API code and the Simple_Swicth.py code that I used. As you can see the picture, I cannot able to ping h1 to h2. can able to help?

Here is my topology code:

#!/usr/bin/python
from mininet.node import Controller, RemoteController, OVSController
from mininet.net import Mininet
from mininet.node import OVSKernelSwitch, UserSwitch
from mininet.cli import CLI
from mininet.link import TCLink, Intf
from mininet.log import setLogLevel, info

def Topo1():
    net = Mininet(controller=RemoteController, switch=OVSKernelSwitch)

    info('*** Adding controll\n')
    c0 = net.addController(name='c0', controller=RemoteController, ip='127.0.0.1', protocol='tcp', port=6633)

    info('*** Add host\n')
    h1 = net.addHost('h1')
    h2 = net.addHost('h2')

    info('*** Add switches\n')
    s1 = net.addSwitch('s1')
    s2 = net.addSwitch('s2')
    s3 = net.addSwitch('s3')
    s4 = net.addSwitch('s4')
    s5 = net.addSwitch('s5')
    s1.linkTo( h1 )
    s1.linkTo( s2 )
    s2.linkTo( s3 )
    s2.linkTo( s4 )
    s3.linkTo( s4 )
    s4.linkTo( s5 )
    s5.linkTo( h2 )

    net.build()
    c0.start
    info('***Starting switches\n')
    net.get('s1').start([c0])
    net.get('s2').start([c0])
    net.get('s3').start([c0])
    net.get('s4').start([c0])
    net.get('s5').start([c0])

    info('***Post configure switches and hosts\n')
    net.start()
    net.pingAll()
    CLI(net)
    net.stop()

if __name__ == '__main__':
    setLogLevel('info')
    Topo1()

here is the simple_switch code for ryu remote controller. Does anyone know which part of the simple_Switch code that I need add extra code to manage ARP loop. And since I do not really good at it don you mind to let me know what kind of code should I use?

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

class SimpleSwitch13(app_manager.RyuApp):
    OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]

    def __init__(self, *args, **kwargs):
        super(SimpleSwitch13, self).__init__(*args, **kwargs)
        self.mac_to_port = {}

    @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

        # install table-miss flow entry
        #
        # We specify NO BUFFER to max_len of the output action due to
        # OVS bug. At this moment, if we specify a lesser number, e.g.,
        # 128, OVS will send Packet-In with invalid buffer_id and
        # truncated packet data. In that case, we cannot output packets
        # correctly.  The bug has been fixed in OVS v2.1.0.
        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, buffer_id=None):
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser

        inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
                                             actions)]
        if buffer_id:
            mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id,
                                    priority=priority, match=match,
                                    instructions=inst)
        else:
            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):
        # If you hit this you might want to increase
        # the "miss_send_length" of your switch
        if ev.msg.msg_len < ev.msg.total_len:
            self.logger.debug("packet truncated: only %s of %s bytes",
                              ev.msg.msg_len, ev.msg.total_len)
        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_protocols(ethernet.ethernet)[0]

        if eth.ethertype == ether_types.ETH_TYPE_LLDP:
            # ignore lldp packet
            return
        dst = eth.dst
        src = eth.src

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

        self.logger.info("packet in %s %s %s %s", dpid, src, dst, in_port)

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

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

        actions = [parser.OFPActionOutput(out_port)]

        # install a flow to avoid packet_in next time
        if out_port != ofproto.OFPP_FLOOD:
            match = parser.OFPMatch(in_port=in_port, eth_dst=dst)
            # verify if we have a valid buffer_id, if yes avoid to send both
            # flow_mod & packet_out
            if msg.buffer_id != ofproto.OFP_NO_BUFFER:
                self.add_flow(datapath, 1, match, actions, msg.buffer_id)
                return
            else:
                self.add_flow(datapath, 1, match, actions)
        data = None
        if msg.buffer_id == ofproto.OFP_NO_BUFFER:
            data = msg.data

        out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id,
                                  in_port=in_port, actions=actions, data=data)
        datapath.send_msg(out)