mininet-wifi examples 官方例子详解(一）

布满荆棘的人生 2022-03-18 04:22 605阅读 0赞

本博客总结了examples文件下面的例子的用法，需要注意的事项以及今后编码需要用到的技巧。有些例子经过了自己的改动。

## 例1 4address ##

IEEE 802.11 (WLAN)帧的报头有四个地址字段。为了在无线分配系统(WDS)链路上透明地传输以太网数据包，IEEE 802.3(以太网)帧被封装在IEEE 802.11 (WLAN)帧中。在这种情况下，所有四个地址字段都被使用  
•以太网帧的发送方  
•以太网帧的接收器  
•WLAN帧的发送器  
•WLAN帧的接收器  
以太网帧的发送方和接收方仅从传输的以太网帧复制。其余的字段允许接收方识别帧是为他准备的，并允许它向(WLAN)发送方确认帧的接收。然而，通常只需要这四个字段中的三个，因此大多数驱动程序不知道如何处理使用所有四个地址字段的帧。换句话说:WDS最重要的组成部分是支持4个地址头。

#!/usr/bin/python
    
    """This example shows how to enable 4-address Warning: It works only when network manager is stopped"""
    
    from mininet.node import Controller
    from mininet.log import setLogLevel, info
    from mn_wifi.link import wmediumd, _4address
    from mn_wifi.cli import CLI_wifi
    from mn_wifi.net import Mininet_wifi
    from mn_wifi.wmediumdConnector import interference
    
    
    def topology():
        "Create a network."
        net = Mininet_wifi(controller=Controller, link=wmediumd,
                           wmediumd_mode=interference, configure4addr=True)
    
        info("*** Creating nodes\n")
        ap1 = net.addAccessPoint('ap1', ssid="ap1-ssid", mod"g",
                                 channel="1", position='30,30,0')
        ap2 = net.addAccessPoint('ap2', ssid="ap2-ssid", mode="g",
                                 channel="1", position='40,60,0')
        ap3 = net.addAccessPoint('ap3', ssid="ap3-ssid", mode="g",
                                 channel="1", position='50,30,0')
        sta1 = net.addStation('sta1', ip="192.168.0.1/24", position='31,32,0')
        sta2 = net.addStation('sta2', ip="192.168.0.2/24", position='32,34,0')
        sta3 = net.addStation('sta3', ip="192.168.0.3/24", position='41,62,0')
        sta4 = net.addStation('sta4', ip="192.168.0.4/24", position='42,64,0')
        sta5 = net.addStation('sta5', ip="192.168.0.5/24", position='51,32,0')
        sta6 = net.addStation('sta6', ip="192.168.0.6/24", position='52,34,0')
        c0 = net.addController('c0')
    
        info("*** Configuring Propagation Model\n")
        net.setPropagationModel(model="logDistance", exp=4.5)
    
        info("*** Configuring wifi nodes\n")
        net.configureWifiNodes()
    
        info("*** Adding Link\n")
        net.addLink(ap1, ap2, cls=_4address) # ap1=ap, ap2=client
        net.addLink(ap1, ap3, cls=_4address) # ap1=ap, ap3=client
        net.addLink(sta1, ap1)
        net.addLink(sta2, ap1)
        net.addLink(sta3, ap2)
        net.addLink(sta4, ap2)
        net.addLink(sta5, ap3)
        net.addLink(sta6, ap3)
    
        net.plotGraph(max_x=100, max_y=100)
    
        info("*** Starting network\n")
        net.build()
        c0.start()
        ap1.start([c0])
        ap2.start([c0])
        ap3.start([c0])
    
        info("*** Running CLI\n")
        CLI_wifi(net)
    
        info("*** Stopping network\n")
        net.stop()
    
    
    if __name__ == '__main__':
        setLogLevel('info')
        topology()

运行结果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70]  
注意事项：

1.  net参数：net = Mininet\_wifi(controller=Controller, link=wmediumd,  
    wmediumd\_mode=interference, configure4addr=True)
2.  addLink参数：net.addLink(ap1, ap2, cls=\_4address) 这时候两个ap就有主从关系：ap2是客户机。
3.  意思是不是ap之间使用以太网连接，sta与ap之间使用wlan连接。  
    ![在这里插入图片描述][20190219103837762.png]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 1]

--------------------

## 例2 active\_scan ##

当sta需要连接特定频率（MHz），可以使用active\_scan功能。  
果网络使用的通道子集已知，则可以使用此选项优化扫描，使其不发生在网络不使用的通道上。示例:scan\_freq=“2412 2437 2462”， freq\_list=“2412 2437 2462”  
![在这里插入图片描述][20190219110556894.png]

#!/usr/bin/python
    
    'This example shows how to work with active scan'
    
    from mininet.node import Controller
    from mininet.log import setLogLevel, info
    from mn_wifi.node import UserAP
    from mn_wifi.cli import CLI_wifi
    from mn_wifi.net import Mininet_wifi
    
    
    def topology():
        "Create a network."
        net = Mininet_wifi(controller=Controller, accessPoint=UserAP)
    
        info("*** Creating nodes\n")
        net.addStation('sta1', passwd='123456789a,123456789a', encrypt='wpa2,wpa2',
                       wlans=2, active_scan=1, scan_freq='2412,2437',
                       freq_list='2412,2437', position='5,10,0')
        net.addStation('sta2', passwd='123456789a', encrypt='wpa2',
                       active_scan=1, scan_freq='2437', freq_list='2437',
                       position='45,10,0')
        ap1 = net.addAccessPoint('ap1', ssid="ssid-1", mode="g", channel="1",
                                 passwd='123456789a', encrypt='wpa2',
                                 position='10,10,0')
        ap2 = net.addAccessPoint('ap2', ssid="ssid-1", mode="g", channel="6",
                                 passwd='123456789a', encrypt='wpa2',
                                 position='40,10,0')
        c0 = net.addController('c0')
    
        info("*** Configuring wifi nodes\n")
        net.configureWifiNodes()
    
        net.plotGraph(max_x=120, max_y=120)
    
        info("*** Starting network\n")
        net.build()
        c0.start()
        ap1.start([c0])
        ap2.start([c0])
    
        info("*** Running CLI\n")
        CLI_wifi(net)
    
        info("*** Stopping network\n")
        net.stop()
    
    
    if __name__ == '__main__':
        setLogLevel('info')
        topology()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 2]  
需要注意的是：

1.  模拟添加了wap2加密的协议
2.  active\_scan标志位设置为1

--------------------

## 例3 adhoc ##

adhoc显示了如何使用adhoc模式设置实验，在这种模式下，工作站无需通过访问点而彼此连接。

#!/usr/bin/python
    
    """This example shows how to work in adhoc mode sta1 <---> sta2 <---> sta3"""
    
    import sys
    
    from mininet.log import setLogLevel, info
    from mn_wifi.link import wmediumd, adhoc
    from mn_wifi.cli import CLI_wifi
    from mn_wifi.net import Mininet_wifi
    from mn_wifi.wmediumdConnector import interference
    
    #adhoc shows how to set up experiments with adhoc mode,
    # where stations connect to each other without passing through an access point.
    
    
    def topology(autoTxPower):
        "Create a network."
        net = Mininet_wifi(link=wmediumd, wmediumd_mode=interference)
    
        info("*** Creating nodes\n")
        if autoTxPower:
            sta1 = net.addStation('sta1', position='10,10,0', range=100)
            sta2 = net.addStation('sta2', position='50,10,0', range=100)
            sta3 = net.addStation('sta3', position='90,10,0', range=100)
        else:
            sta1 = net.addStation('sta1', position='10,10,0')
            sta2 = net.addStation('sta2', position='50,10,0')
            sta3 = net.addStation('sta3', position='90,10,0')
    
        net.setPropagationModel(model="logDistance", exp=4)
    
        info("*** Configuring wifi nodes\n")
        net.configureWifiNodes()
    
        net.plotGraph(max_x=100, max_y=100)
    
        info("*** Creating links\n")
        net.addLink(sta1, cls=adhoc, ssid='adhocNet',
                    mode='g', channel=5, ht_cap='HT40+')
        net.addLink(sta2, cls=adhoc, ssid='adhocNet',
                    mode='g', channel=5)
        net.addLink(sta3, cls=adhoc, ssid='adhocNet',
                    mode='g', channel=5, ht_cap='HT40+')
    
        info("*** Starting network\n")
        net.build()
    
        info("*** Running CLI\n")
        CLI_wifi(net)
    
        info("*** Stopping network\n")
        net.stop()
    
    
    if __name__ == '__main__':
        setLogLevel('info')
        #三元表达式来确定命令行参数
        autoTxPower = True if '-a' in sys.argv else False
        topology(autoTxPower)

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 3]  
可以看到三个站点通过wifi同时连接。

1.  将addLink参数cls编程adhoc
2.  autoTxPower = True if ‘-a’ in sys.argv else False 这里使用python三元表达式来根据输入是否有-a来确定传入topo的参数到底是什么，例如下面：

> sudo python [adhoc.py][] \-a  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 4]

加上这个参数之后，每一个sta就有一个默认的range了。因此这个例子可以学到如果给我们的网络传入外部参数，这个在协议设计优化是有很大帮助的。对于不同的协议，可以在终端使用不同的参数来更改。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70]: /images/20220318/756bc53c39844d059aa712129c658791.png
[20190219103837762.png]: /images/20220318/0258012d396e46cdb70330cf38b33f65.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 1]: /images/20220318/7338e74909c84d81938dc1805dddb0be.png
[20190219110556894.png]: /images/20220318/f0e75342dc3448ac8d867e6f91bf065b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 2]: /images/20220318/d9ce9e5eba5e4441891c657e79ce8d18.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 3]: /images/20220318/65c49143acfe415d8ec9cb213bdeb7cd.png
[adhoc.py]: http://adhoc.py
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjM3Mjg3OQ_size_16_color_FFFFFF_t_70 4]: /images/20220318/4059923eed264ab5a2c1ff8dbe1b9dae.png