mininet實驗 動態改變轉發規則實驗

寫在前面

---

本實驗參考

• POX腳本設置好控制器的轉發策略，所以只要理解腳本。
• mininet腳本設置好拓撲和相關信息，所以也只要理解腳本。
• POX腳本目前基本看不懂。
• 本實驗我學會了：POX控制器Web界面，第一次真正的看到了流表項。

實驗拓撲

---

• 在該環境下，假設H1 ping H4，初始的路由規則是S1-S2-S5，一秒后，路由轉發規則變為S1-S3-S5，再過一秒，規則變為S1-S4-S5，然后再回到最初的轉發規則S1-S2-S5。通過這個循環調度的例子動態地改變交換機的轉發規則。

實驗步驟

---

1.搭建環境

• 安裝了mininet的虛擬機。
• 安裝了pox的虛擬機。

2.創建腳本

• /pox目錄下新建文件lab_controller.py，編輯其內容：

from pox.core import core

import pox.openflow.libopenflow_01 as of

from pox.lib.util import dpidToStr

from pox.lib.addresses import IPAddr, EthAddr

from pox.lib.packet.arp import arp

from pox.lib.packet.ethernet import ethernet, ETHER_BROADCAST

from pox.lib.packet.packet_base import packet_base

from pox.lib.packet.packet_utils import *

import pox.lib.packet as pkt

from pox.lib.recoco import Timer

import time



log = core.getLogger()



s1_dpid=0

s2_dpid=0

s3_dpid=0

s4_dpid=0

s5_dpid=0



s1_p1=0

s1_p4=0

s1_p5=0

s1_p6=0

s2_p1=0

s3_p1=0

s4_p1=0



pre_s1_p1=0

pre_s1_p4=0

pre_s1_p5=0

pre_s1_p6=0

pre_s2_p1=0

pre_s3_p1=0

pre_s4_p1=0



turn=0



def getTheTime():  #fuction to create a timestamp

  flock = time.localtime()

  then = "[%s-%s-%s" %(str(flock.tm_year),str(flock.tm_mon),str(flock.tm_mday))



  if int(flock.tm_hour)<10:

    hrs = "0%s" % (str(flock.tm_hour))

  else:

    hrs = str(flock.tm_hour)

  if int(flock.tm_min)<10:

    mins = str(flock.tm_min)

    secs = "0%s" % (str(flock.tm_sec))

  else:

    secs = str(flock.tm_sec)



  then +="]%s.%s.%s" % (hrs,mins,secs)

  return then





def _timer_func ():

  global s1_dpid, s2_dpid, s3_dpid, s4_dpid, s5_dpid,turn





  #print getTheTime(), "sent the port stats request to s1_dpid"



  if turn==0:

      msg = of.ofp_flow_mod()

      msg.command=of.OFPFC_MODIFY_STRICT

      msg.priority =100

      msg.idle_timeout = 0

      msg.hard_timeout = 0

      msg.match.dl_type = 0x0800

      msg.match.nw_dst = "10.0.0.4"

      msg.actions.append(of.ofp_action_output(port = 5))

      core.openflow.getConnection(s1_dpid).send(msg)

      turn=1

      return



  if turn==1:

      msg = of.ofp_flow_mod()

      msg.command=of.OFPFC_MODIFY_STRICT

      msg.priority =100

      msg.idle_timeout = 0

      msg.hard_timeout = 0

      msg.match.dl_type = 0x0800

      msg.match.nw_dst = "10.0.0.4"

      msg.actions.append(of.ofp_action_output(port = 6))

      core.openflow.getConnection(s1_dpid).send(msg)

      turn=2

      return



  if turn==2:

      msg = of.ofp_flow_mod()

      msg.command=of.OFPFC_MODIFY_STRICT

      msg.priority =100

      msg.idle_timeout = 0

      msg.hard_timeout = 0

      msg.match.dl_type = 0x0800

      msg.match.nw_dst = "10.0.0.4"

      msg.actions.append(of.ofp_action_output(port = 4))

      turn=0

      return



def _handle_portstats_received (event):

  global s1_p1,s1_p4, s1_p5, s1_p6, s2_p1, s3_p1, s4_p1

  global pre_s1_p1,pre_s1_p4, pre_s1_p5, pre_s1_p6, pre_s2_p1, pre_s3_p1, pre_s4_p1



  if event.connection.dpid==s1_dpid:

    for f in event.stats:

      if int(f.port_no)<65534:

        if f.port_no==1:

          pre_s1_p1=s1_p1

          s1_p1=f.rx_packets


        if f.port_no==4:

          pre_s1_p4=s1_p4

          s1_p4=f.tx_packets

          #s1_p4=f.tx_bytes


        if f.port_no==5:

          pre_s1_p5=s1_p5

          s1_p5=f.tx_packets

        if f.port_no==6:

          pre_s1_p6=s1_p6

          s1_p6=f.tx_packets



     for f in event.stats:

       if int(f.port_no)<65534:

         if f.port_no==1:

           pre_s2_p1=s2_p1

           s2_p1=f.rx_packets

           #s2_p1=f.rx_bytes


  if event.connection.dpid==s3_dpid:

     for f in event.stats:

       if int(f.port_no)<65534:

         if f.port_no==1:

           pre_s3_p1=s3_p1

           s3_p1=f.rx_packets




  if event.connection.dpid==s4_dpid:

     for f in event.stats:

       if int(f.port_no)<65534:

         if f.port_no==1:

           pre_s4_p1=s4_p1

           s4_p1=f.rx_packets




def _handle_ConnectionUp (event):

  global s1_dpid, s2_dpid, s3_dpid, s4_dpid, s5_dpid

  print "ConnectionUp: ",dpidToStr(event.connection.dpid)



  #remember the connection dpid for switch

  for m in event.connection.features.ports:

    if m.name == "s1-eth1":

      s1_dpid = event.connection.dpid

      print "s1_dpid=", s1_dpid

    elif m.name == "s2-eth1":

      s2_dpid = event.connection.dpid

      print "s2_dpid=", s2_dpid

    elif m.name == "s3-eth1":

      s3_dpid = event.connection.dpid

    elif m.name == "s4-eth1":

      s4_dpid = event.connection.dpid

      print "s4_dpid=", s4_dpid

    elif m.name == "s5-eth1":

      s5_dpid = event.connection.dpid

      print "s5_dpid=", s5_dpid



  if s1_dpid<>0 and s2_dpid<>0 and s3_dpid<>0 and s4_dpid<>0:

    Timer(1, _timer_func, recurring=True)



def _handle_PacketIn(event):

  global s1_dpid, s2_dpid, s3_dpid, s4_dpid, s5_dpid



  packet=event.parsed




  if event.connection.dpid==s1_dpid:

     a=packet.find('arp')

     if a and a.protodst=="10.0.0.4":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=4))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.5":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=5))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.6":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=6))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.1":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=1))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.2":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=2))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.3":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=3))

       event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.1"

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.2"

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.3"

     msg.actions.append(of.ofp_action_output(port = 3))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 1

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.4"

     msg.actions.append(of.ofp_action_output(port = 4))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.5"

     msg.actions.append(of.ofp_action_output(port = 5))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.6"

     msg.actions.append(of.ofp_action_output(port = 6))

     event.connection.send(msg)



  elif event.connection.dpid==s2_dpid:

     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 1

     msg.match.dl_type=0x0806

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 1

     msg.match.dl_type=0x0800

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 2

     msg.match.dl_type=0x0806

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 2

     msg.match.dl_type=0x0800

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



  elif event.connection.dpid==s3_dpid:

     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 1

     msg.match.dl_type=0x0806

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 1

     msg.match.dl_type=0x0800

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 2

     msg.match.dl_type=0x0806

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 2

     msg.match.dl_type=0x0800

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



  elif event.connection.dpid==s4_dpid:

     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 1

     msg.match.dl_type=0x0806

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 1

     msg.match.dl_type=0x0800

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 2

     msg.match.dl_type=0x0806

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =10

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.in_port = 2

     msg.match.dl_type=0x0800

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



  elif event.connection.dpid==s5_dpid:

     a=packet.find('arp')

     if a and a.protodst=="10.0.0.4":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=4))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.5":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=5))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.6":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=6))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.1":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=1))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.2":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=2))

       event.connection.send(msg)



     if a and a.protodst=="10.0.0.3":

       msg = of.ofp_packet_out(data=event.ofp)

       msg.actions.append(of.ofp_action_output(port=3))

       event.connection.send(msg)






     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.1"

     msg.actions.append(of.ofp_action_output(port = 1))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.2"

     msg.actions.append(of.ofp_action_output(port = 2))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.3"

     msg.actions.append(of.ofp_action_output(port = 3))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.4"

     msg.actions.append(of.ofp_action_output(port = 4))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.5"

     msg.actions.append(of.ofp_action_output(port = 5))

     event.connection.send(msg)



     msg = of.ofp_flow_mod()

     msg.priority =100

     msg.idle_timeout = 0

     msg.hard_timeout = 0

     msg.match.dl_type = 0x0800

     msg.match.nw_dst = "10.0.0.6"

     msg.actions.append(of.ofp_action_output(port = 6))

     event.connection.send(msg)



def launch ():

  global start_time

  core.openflow.addListenerByName("PortStatsReceived",_handle_portstats_received)

  core.openflow.addListenerByName("ConnectionUp", _handle_ConnectionUp)

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

• 該腳本實現了動態轉發策略。
• 我猜測基本思想應該是，基於時間來給交換機s1下發流表項。
• 在Mininet中創建文件mymininet.py。編輯其內容為：

#!/usr/bin/python

 

from mininet.topo import Topo

from mininet.net import Mininet

from mininet.node import CPULimitedHost

from mininet.link import TCLink

from mininet.util import dumpNodeConnections

from mininet.log import setLogLevel

from mininet.node import Controller 

from mininet.cli import CLI

from functools import partial

from mininet.node import RemoteController

import os

 

 

class MyTopo(Topo):

    "Single switch connected to n hosts."

    def __init__(self):

        Topo.__init__(self)

        s1=self.addSwitch('s1')

        s2=self.addSwitch('s2')

        s3=self.addSwitch('s3')

        s4=self.addSwitch('s4')

        s5=self.addSwitch('s5') 

        h1=self.addHost('h1')

        h2=self.addHost('h2')

        h3=self.addHost('h3')

        h4=self.addHost('h4')

        h5=self.addHost('h5')

        h6=self.addHost('h6')

         

        self.addLink(h1, s1, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True)

        self.addLink(h2, s1, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(h3, s1, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True)

        self.addLink(s1, s2, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s1, s3, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s1, s4, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s2, s5, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s3, s5, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True)  

        self.addLink(s4, s5, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s5, h4, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s5, h5, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

        self.addLink(s5, h6, bw=1, delay='10ms', loss=0, max_queue_size=1000, use_htb=True) 

 

def perfTest():

    "Create network and run simple performance test"

    topo = MyTopo()


    net = Mininet(topo=topo, host=CPULimitedHost, link=TCLink, controller=partial(RemoteController, ip='10.0.0.13', port=6633))

    net.start()

    print "Dumping host connections"

    dumpNodeConnections(net.hosts)

    h1,h2,h3=net.get('h1','h2','h3')

    h4,h5,h6=net.get('h4','h5','h6')

    h1.setMAC("0:0:0:0:0:1")

    h2.setMAC("0:0:0:0:0:2")

    h3.setMAC("0:0:0:0:0:3")

    h4.setMAC("0:0:0:0:0:4")

    h5.setMAC("0:0:0:0:0:5")

    h6.setMAC("0:0:0:0:0:6")

    CLI(net)

    net.stop()

 

if __name__ == '__main__':

    setLogLevel('info')

    perfTest()

• 該腳本設置了拓撲。基本可以理解。

3.運行腳本

• /pox目錄下運行腳本lab_controller.py

./pox.py lab_controller

• 在Mininet下運行腳本mymininet.py

chmod +x mymininet.py
./mymininet.py

• mininet終端信息

• POX控制器終端信息

• 現在我們通過h1向h4發包，來檢測動態轉發功能。
• 在mininet終端輸入：

h1 ping -i 0.1 h4 #h1每秒向h4發10個包

• 這時在POX界面並沒有出現有用的信息，反而是一些warning信息。

4.解決方案

• 既然在終端中沒法看到發送的細節，我想到了Web界面。別的控制器都有UI界面POX也應該有吧？
• 我在一篇博客中找到了POX UI界面的實現方式：Poxdesk。

參考博客

• 運行POX腳本時要想使用poxdesk必須多加一些參數，對於本實驗運行lab_controller.py時，命令如下：

./pox.py lab_controller web messenger messenger.log_service messenger.ajax_transport openflow.of_service poxdesk

• 通用命令：

./pox.py 要運行的腳本 web messenger messenger.log_service messenger.ajax_transport openflow.of_service poxdesk

• 瀏覽器中輸入：http://pox-ip:8000/poxdesk 來訪問界面，其中pox-ip是本機IP地址。
• 進入Web界面后，我們打開s1的flowtable窗口。可以發現：對於目的是10.0.0.4（主機h4）的流表項在周期性變化，action中output端口在5，6之間切換。但是沒有4（交換機s2），這個問題沒有解決，可能是腳本本身的問題。

5.具體的連接圖

• 通過mininet中的net命令可以得拓撲的詳細信息，我簡單的畫了個示意圖便於理解：

存在問題

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• 端口切換時，為什么不能切換到s2？