一、基本要求
h1 ping h2、h2和h3的tcpdump抓包结果
使用 tcpdump 验证Hub模块
使用 tcpdump 验证Switch模块
L2_learning模块代码流程图
(二)进阶要求
1. 重新搭建(一)的拓扑,此时交换机内无流表规则,拓扑内主机互不相通;编写Python程序自定义一个POX模块SendFlowInSingle3,并且将拓扑连接至SendFlowInSingle3(默认端口6633),实现向s1发送流表规则使得所有主机两两互通。
生成拓扑
sudo mn --topo=single,3 --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow10
SendFlowInSingle3代码
from pox.core import core
import pox.openflow.libopenflow_01 as of
class SendFlowInSingle3(object):
def __init__ (self):
core.openflow.addListeners(self)
def _handle_ConnectionUp(self,event):
#设置数据包从端口1进,从端口2和端口3出
msg = of.ofp_flow_mod()# 使用ofp_flow_mod()的方法向交换机来下发流表
msg.priority = 1#设置msg的优先级
msg.match.in_port = 1#设置在端口1接收数据包
msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL))#增加转发向所有端口的动作
event.connection.send(msg)#通过send函数向交换机发送所设定的消息
#设置数据包从端口2进,从端口1和端口3出
msg = of.ofp_flow_mod()
msg.priority = 1
msg.match.in_port = 2
msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL))
event.connection.send(msg)
#设置数据包从端口3进,从端口1和端口2出
msg = of.ofp_flow_mod()
msg.priority = 1
msg.match.in_port = 3
msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL))
event.connection.send(msg)
def launch ():
core.registerNew(SendFlowInSingle3)
2. 基于进阶1的代码,完成ODL实验的硬超时功能
SendPoxHardTimeOut代码
from pox.core import core
import pox.openflow.libopenflow_01 as of
class SendPoxHardTimeOut(object):
def __init__(self):
core.openflow.addListeners(self)
def _handle_ConnectionUp(self, event):
msg = of.ofp_flow_mod()
msg.priority = 3
msg.match.in_port = 1
msg.hard_timeout = 10 #硬超时10秒
event.connection.send(msg)
msg = of.ofp_flow_mod()
msg.priority = 1
msg.match.in_port = 1
msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL))
event.connection.send(msg)
msg = of.ofp_flow_mod()
msg.priority = 3
msg.match.in_port = 3
msg.hard_timeout = 10
event.connection.send(msg)
msg = of.ofp_flow_mod()
msg.priority = 1
msg.match.in_port = 3
msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL))
event.connection.send(msg)
def launch():
core.registerNew(SendPoxHardTimeOut)
运行SendPoxHardTimeOut
./pox.py log.level --DEBUG forwarding.SendPoxHardTimeOut
3.总结
1.在pox目录下创建 SendFlowInSingle3.py 和 SendPoxHardTimeOut.py 文件时需要加 sudo ,否则无法创建成功.
2.
msg = of.ofp_flow_mod()
msg.priority = 3
msg.match.in_port = 3
msg.hard_timeout = 10
event.connection.send(msg)
msg = of.ofp_flow_mod()
msg.priority = 1
msg.match.in_port = 3
msg.actions.append(of.ofp_action_output(port = of.OFPP_ALL))
event.connection.send(msg)
对于同一个端口的操作,通过msg.priority
判断先后顺序。