淺析內網資訊收集
阿新 • • 發佈:2020-09-22
實驗 4 :Open vSwitch 實驗 —— Mininet 中使用 OVS 命令
一、實驗目的
Mininet 安裝之後,會連帶安裝 Open vSwitch,可以直接通過 Python 指令碼呼叫 Open vSwitch 命令,從而直接控制 Open vSwitch,通過實驗瞭解呼叫控制的方法。
二 、實驗任務
在本實驗中,使用 Mininet 基於 Python 的指令碼,呼叫“ovs-vsctl”命令直接控制Open vSwitch。使用預設的交換機泛洪規則,設定更高的優先順序規則進行預先定義 IP 報文的轉發。在多個交換機中通過設定不同 TOS 值的資料包將通過不同的方式到達目的地址,驗證主機間的連通性及到達目的地址的時間。
三 、 實驗步驟
1. 實驗環境
安裝了 Ubuntu 18.04.5 Desktop amd64 的虛擬機器
2. 實驗過程
SDNLAB 實驗參考資料:https://www.sdnlab.com/15083.html
( 1 )建立 ovsSingleBr.py 指令碼並新增內容,程式碼參考SDNLAB指令碼對應的拓撲如上圖所示,執行 ovsSingleBr.py,在沒有控制器的情況下,在 Mininet 指令碼中通過呼叫 ovs 命令直接向 switch0 交換機下發流表,將入埠號為 1/2/3 的資料包泛洪廣播,並對目的地址為 192.168.123.1/2/3 的資料包分別從1/2/3 埠轉發出去。之後測試 h0 ping h1,h0 ping h2,網路連通。
# ovsSingleBr.py #!/usr/bin/python from mininet.net import Mininet from mininet.node import Node from mininet.link import Link from mininet.log import setLogLevel, info def myNet(): "Create network from scratch using Open vSwitch." info( "*** Creating nodes\n" ) switch0 = Node( 's0', inNamespace=False ) h0 = Node( 'h0' ) h1 = Node( 'h1' ) h2 = Node( 'h2' ) info( "*** Creating links\n" ) Link( h0, switch0) Link( h1, switch0) Link( h2, switch0) info( "*** Configuring hosts\n" ) h0.setIP( '192.168.123.1/24' ) h1.setIP( '192.168.123.2/24' ) h2.setIP( '192.168.123.3/24' ) info( "*** Starting network using Open vSwitch\n" ) switch0.cmd( 'ovs-vsctl del-br dp0' ) switch0.cmd( 'ovs-vsctl add-br dp0' ) for intf in switch0.intfs.values(): print intf print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf ) # Note: controller and switch are in root namespace, and we # can connect via loopback interface #switch0.cmd( 'ovs-vsctl set-controller dp0 tcp:127.0.0.1:6633' ) print switch0.cmd(r'ovs-vsctl show') print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=1,in_port=1,actions=flood' ) print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=1,in_port=2,actions=flood' ) print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=1,in_port=3,actions=flood' ) print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.1,actions=output:1' ) print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,actions=output:2' ) print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.3,actions=output:3') #switch0.cmd('tcpdump -i s0-eth0 -U -w aaa &') #h0.cmd('tcpdump -i h0-eth0 -U -w aaa &') info( "*** Running test\n" ) h0.cmdPrint( 'ping -c 3 ' + h1.IP() ) h0.cmdPrint( 'ping -c 3 ' + h2.IP() ) #print switch0.cmd( 'ovs-ofctl show dp0' ) #print switch0.cmd( 'ovs-ofctl dump-tables dp0' ) #print switch0.cmd( 'ovs-ofctl dump-ports dp0' ) #print switch0.cmd( 'ovs-ofctl dump-flows dp0' ) #print switch0.cmd( 'ovs-ofctl dump-aggregate dp0' ) #print switch0.cmd( 'ovs-ofctl queue-stats dp0' ) info( "*** Stopping network\n" ) switch0.cmd( 'ovs-vsctl del-br dp0' ) switch0.deleteIntfs() info( '\n' ) if __name__ == '__main__': setLogLevel( 'info' ) info( '*** Scratch network demo (kernel datapath)\n' ) Mininet.init() myNet()
( 2 ) 建立 ovsMultiBr.py 指令碼並新增內容,程式碼參考 SDNLAB 指令碼對應的拓撲如上圖所示,執行 ovsMultiBr.py,在沒有控制器的情況下,在Mininet 指令碼中通過呼叫 ovs 命令給多個交換機下發流表,通過 h0 ping h1 操作測試驗證主機間的連通性,並通過 -Q 引數設定不通的 tos 值檢視主機間的連通性。通過驗證發現,tos 值設定越大,時間使用越少。
# ovsMultiBr.py #!/usr/bin/python from mininet.net import Mininet from mininet.node import Node from mininet.link import TCLink from mininet.log import setLogLevel, info def myNet(): "Create network from scratch using Open vSwitch." info( "*** Creating nodes\n" ) switch0 = Node( 's0', inNamespace=False ) switch1 = Node( 's1', inNamespace=False ) switch2 = Node( 's2', inNamespace=False ) switch3 = Node( 's3', inNamespace=False ) switch4 = Node( 's4', inNamespace=False ) h0 = Node( 'h0' ) h1 = Node( 'h1' ) info( "*** Creating links\n" ) linkopts0=dict(bw=100, delay='1ms', loss=0) linkopts1=dict(bw=1, delay='100ms', loss=0) linkopts2=dict(bw=10, delay='50ms', loss=0) linkopts3=dict(bw=100, delay='1ms', loss=0) TCLink( h0, switch0, **linkopts0) TCLink( switch0, switch1, **linkopts0) TCLink( switch0, switch2, **linkopts0) TCLink( switch0, switch3, **linkopts0) TCLink( switch1, switch4,**linkopts1) TCLink( switch2, switch4,**linkopts2) TCLink( switch3, switch4,**linkopts3) TCLink( h1, switch4, **linkopts0) info( "*** Configuring hosts\n" ) h0.setIP( '192.168.123.1/24' ) h1.setIP( '192.168.123.2/24' ) info( str( h0 ) + '\n' ) info( str( h1 ) + '\n' ) info( "*** Starting network using Open vSwitch\n" ) switch0.cmd( 'ovs-vsctl del-br dp0' ) switch0.cmd( 'ovs-vsctl add-br dp0' ) switch1.cmd( 'ovs-vsctl del-br dp1' ) switch1.cmd( 'ovs-vsctl add-br dp1' ) switch2.cmd( 'ovs-vsctl del-br dp2' ) switch2.cmd( 'ovs-vsctl add-br dp2' ) switch3.cmd( 'ovs-vsctl del-br dp3' ) switch3.cmd( 'ovs-vsctl add-br dp3' ) switch4.cmd( 'ovs-vsctl del-br dp4' ) switch4.cmd( 'ovs-vsctl add-br dp4' ) for intf in switch0.intfs.values(): print intf print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf ) for intf in switch1.intfs.values(): print intf print switch1.cmd( 'ovs-vsctl add-port dp1 %s' % intf ) for intf in switch2.intfs.values(): print intf print switch2.cmd( 'ovs-vsctl add-port dp2 %s' % intf ) for intf in switch3.intfs.values(): print intf print switch3.cmd( 'ovs-vsctl add-port dp3 %s' % intf ) for intf in switch4.intfs.values(): print intf print switch4.cmd( 'ovs-vsctl add-port dp4 %s' % intf ) print switch1.cmd(r'ovs-ofctl add-flow dp1 idle_timeout=0,priority=1,in_port=1,actions=flood' ) print switch1.cmd(r'ovs-ofctl add-flow dp1 idle_timeout=0,priority=1,in_port=1,actions=output:2' ) print switch1.cmd(r'ovs-ofctl add-flow dp1 idle_timeout=0,priority=1,in_port=2,actions=output:1' ) print switch2.cmd(r'ovs-ofctl add-flow dp2 idle_timeout=0,priority=1,in_port=1,actions=output:2' ) print switch2.cmd(r'ovs-ofctl add-flow dp2 idle_timeout=0,priority=1,in_port=2,actions=output:1' ) print switch3.cmd(r'ovs-ofctl add-flow dp3 idle_timeout=0,priority=1,in_port=1,actions=output:2' ) print switch3.cmd(r'ovs-ofctl add-flow dp3 idle_timeout=0,priority=1,in_port=2,actions=output:1' ) print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=1,actions=output:4' ) print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=2,actions=output:4' ) print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=3,actions=output:4' ) print switch4.cmd(r'ovs-ofctl add-flow dp4 idle_timeout=0,priority=1,in_port=4,actions=output:3' ) #print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,actions=output:4') print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,nw_tos=0x10,actions=output:2') print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,nw_tos=0x20,actions=output:3') print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.2,nw_tos=0x30,actions=output:4') #print switch0.cmd(r'ovs-ofctl add-flow dp0 idle_timeout=0,priority=10,ip,nw_dst=192.168.123.1,actions=output:1') #switch0.cmd('tcpdump -i s0-eth0 -U -w aaa &') #h0.cmd('tcpdump -i h0-eth0 -U -w aaa &') info( "*** Running test\n" ) h0.cmdPrint( 'ping -Q 0x10 -c 3 ' + h1.IP() ) h0.cmdPrint( 'ping -Q 0x20 -c 3 ' + h1.IP() ) h0.cmdPrint( 'ping -Q 0x30 -c 3 ' + h1.IP() ) #h1.cmdPrint('iperf -s -p 12345 -u &') #h0.cmdPrint('iperf -c ' + h1.IP() +' -u -b 10m -p 12345 -t 10 -i 1') #print switch0.cmd( 'ovs-ofctl show dp0' ) #print switch1.cmd( 'ovs-ofctl show dp1' ) #print switch2.cmd( 'ovs-ofctl show dp2' ) #print switch3.cmd( 'ovs-ofctl show dp3' ) #print switch4.cmd( 'ovs-ofctl show dp4' ) #print switch0.cmd( 'ovs-ofctl dump-tables dp0' ) #print switch0.cmd( 'ovs-ofctl dump-ports dp0' ) #print switch0.cmd( 'ovs-ofctl dump-flows dp0' ) #print switch0.cmd( 'ovs-ofctl dump-aggregate dp0' ) #print switch0.cmd( 'ovs-ofctl queue-stats dp0' ) #print "Testing video transmission between h1 and h2" #h1.cmd('./myrtg_svc -u > myrd &') #h0.cmd('./mystg_svc -trace st 192.168.123.2') info( "*** Stopping network\n" ) switch0.cmd( 'ovs-vsctl del-br dp0' ) switch0.deleteIntfs() switch1.cmd( 'ovs-vsctl del-br dp1' ) switch1.deleteIntfs() switch2.cmd( 'ovs-vsctl del-br dp2' ) switch2.deleteIntfs() switch3.cmd( 'ovs-vsctl del-br dp3' ) switch3.deleteIntfs() switch4.cmd( 'ovs-vsctl del-br dp4' ) switch4.deleteIntfs() info( '\n' ) if __name__ == '__main__': setLogLevel( 'info' ) info( '*** Scratch network demo (kernel datapath)\n' ) Mininet.init() myNet()
四 、實驗 要求
1. 學習 ovsSingleBr.py 和 ovsMultiBr.py,在下圖拓撲中實現一個 VLAN。
上述程式碼將 h0 和 h2 劃分在 VLAN0 中,h1 和 h3 劃分在 VLAN1 中,由於拓撲沒有控制器,並且初始化時刪除了交換機中的所有流表,因此除非下發流表,否則主機之間網路無法連通。請嘗試修改程式碼,利用 ovs 命令直接下發 VLAN 設定的流表項,最終測試 h0 和 h2 互通,h1 和 h3 互通,其餘主機均不通,結果如下圖。
(這裡用h1和h3互通,h2和h4互通)
# test4.py # coding=UTF-8 #!/usr/bin/python from mininet.net import Mininet from mininet.link import TCLink from mininet.node import Node from mininet.log import setLogLevel, info from mininet.cli import CLI def test4(): "Create network from scratch using Open vSwitch." net = Mininet() info( "*** Creating nodes\n" ) switch0 = net.addSwitch( 's0' ) switch1 = net.addSwitch( 's1' ) h1 = net.addHost( 'h1' ) h2 = net.addHost( 'h2' ) h3 = net.addHost( 'h3' ) h4 = net.addHost( 'h4' ) info( "*** Creating links\n" ) net.addLink( h1, switch0 ) net.addLink( h2, switch0 ) net.addLink( h3, switch0 ) net.addLink( h4, switch0 ) net.addLink( switch1, switch0 ) info( "*** Configuring hosts\n" ) h1.setIP( '192.168.123.1/24' ) h2.setIP( '192.168.123.2/24' ) h3.setIP( '192.168.123.3/24' ) h4.setIP( '192.168.123.4/24' ) info( str( h1 ) + '\n' ) info( str( h2 ) + '\n' ) info( str( h3 ) + '\n' ) info( str( h4 ) + '\n' ) net.start() CLI(net) net.stop() if __name__=='__main__': setLogLevel( 'info' ) info( '*** Scratch network demo (kernel datapath)\n' ) Mininet.init() test4()
sudo ovs-ofctl -O OpenFlow13 add-flow s0 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:3 sudo ovs-ofctl -O OpenFlow13 add-flow s0 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:3 sudo ovs-ofctl -O OpenFlow13 add-flow s0 priority=1,dl_vlan=0,actions=pop_vlan,output:1 sudo ovs-ofctl -O OpenFlow13 add-flow s0 priority=1,dl_vlan=1,actions=pop_vlan,output:2 sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=1,actions=push_vlan:0x8100,set_field:4096-\>vlan_vid,output:3 sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,in_port=2,actions=push_vlan:0x8100,set_field:4097-\>vlan_vid,output:3 sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=0,actions=pop_vlan,output:1 sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=1,dl_vlan=1,actions=pop_vlan,output:2