如何在POX控制器中增加arp_应答器arp应答超时？

Question

我试图在SDN上显示DOS攻击。我正在使用带有POX控制器的Mininet。我已使用python修改控制器，以不在交换机中注册PING流量的流规则。然而，即使我ping了一个不属于网络的未知主机，尽管ARP泛滥，控制器似乎仍然运行良好。我想这是因为ARP回复超时。如何增加ARP回复超时，以便控制器在声明找不到主机之前至少等待30秒。这是迄今为止我的控制器的代码

"""
A super simple OpenFlow learning switch that installs rules for
each pair of L2 addresses.
"""

# These next two imports are common POX convention
from pox.core import core
import pox.openflow.libopenflow_01 as of


# Even a simple usage of the logger is much nicer than print!
log = core.getLogger()


# This table maps (switch,MAC-addr) pairs to the port on 'switch' at
# which we last saw a packet *from* 'MAC-addr'.
# (In this case, we use a Connection object for the switch.)
table = {}


# To send out all ports, we can use either of the special ports
# OFPP_FLOOD or OFPP_ALL.  We'd like to just use OFPP_FLOOD,
# but it's not clear if all switches support this, so we make
# it selectable.
all_ports = of.OFPP_FLOOD


# Handle messages the switch has sent us because it has no
# matching rule.
def _handle_PacketIn (event):
  packet = event.parsed

  # Learn the source
  table[(event.connection,packet.src)] = event.port

  dst_port = table.get((event.connection,packet.dst))

  if dst_port is None:
    # We don't know where the destination is yet.  So, we'll just
    # send the packet out all ports (except the one it came in on!)
    # and hope the destination is out there somewhere. :)
    msg = of.ofp_packet_out(data = event.ofp)
    msg.actions.append(of.ofp_action_output(port = all_ports))
    event.connection.send(msg)
    log.debug("Flooding packets to all ports")
  else:
    # Since we know the switch ports for both the source and dest
    # MACs, we can install rules for both directions.
    icmp_found = packet.find('icmp')
    msg = of.ofp_packet_out()
    msg.data = event.ofp
    msg.actions.append(of.ofp_action_output(port = dst_port))
    event.connection.send(msg)
    log.debug("Installing %s <-> %s" % (packet.src, packet.dst))
    del table[(event.connection, packet.src)]
    del table[(event.connection, packet.dst)]
    # log.debug(table)

def launch (disable_flood = False):
  global all_ports
  if disable_flood:
    all_ports = of.OFPP_ALL

  core.openflow.addListenerByName("PacketIn", _handle_PacketIn)

  log.info("Pair-Learning switch running.")