mininet | node openflow network | Networking library

I think I see what is going on in the source, but i have not run the framework to confirm it.

It looks like mininet inatalls a NAT rule for every node:

I make a test with pycharm and if you install the library with the command : pip install mininet

your import may not have any error

maybe you installed your library with : sudo pip install mininet and your library is only available for root user

try sudo pip uninstall mininet and pip install mininet

A FlowStatsReply contains statistics for each flow installed on the switch. Since flows do not have dedicated unique identifiers, they are instead identified by their match fields. If a flow rule does not match on a certain header field, its corresponding flow entry in the FlowStatsReply won't contain that field either.

If you look at SimpleSwitch13, which SimpleMonitor13 inherits from, you will find that the controller installs flows in its _packet_in_handler with the following match:

Replace print(net.hosts[0].cmd('python3 xmlrpc_server.py')) with print(net.hosts[0].sendCmd('python3 xmlrpc_server.py')). Connection is sometimes refused, but that issue can be resolved with exception handling on the client script.

You should go through some of POX APIs in the POX documentation. It has a detailed explanation with some examples, which I find to be enough for getting started with building your own POX Component (i.e. what you referred to as a python file).

As quoted from this teaching material:

In general a POX controller consists of three parts:

1.Listener

2.Control logic

3.Messenger

First you need to figure out the type of the event you want the controller to listen to (e.g., ConnectionUp, PacketIn, etc).

Then using some logic you can distinguish between different flows and attach a proper action for a specific flow.

Finally you send the message to the switch to add the new rule in the Openflow table.

Installing new flow rules falls under the control logic part mentioned above, and is explained, with examples, under the OpenFlow Messages section: Flow table modification.

tldr;

Unfortunately, I could not find any way to get TCP tracepoints to work in Mininet, which is what ftrace would uses. The reason for this is that the mininet's /sys/kern/debug directory is empty, i.e., tracing cannot be enabled.

Options:

1. Using mininet-tracing (not recommended)

There probably is a way to get the kernel to include this, or you could use https://github.com/mininet/mininet-tracing which might get you what you need, but I have seen reports that it is slow, and has been updated 9 years ago...

2. Writing a new kernel module (I have tested this and it works)

What I found as a solution instead, was to force printing for the TCP I had in mind and then take a look at the results that way. In order to enable this, you would essentially need to extend some of TCP's behaviour and (quite possibly) reuse the TCP module you have in mind. And create a new kernel module.

Here I have provided an example that you can use. It logs socket information on each ACK. I also included a Makefile and a script to load/unload the kernel module. After you enable the module and let some traffic flow (assuming you are on a debian-based linux) you should be able to find the logs of your TCP in /var/log/kern.log.

Note: This is a hacky way around the issue, but was good enough for my needs, and hopefully can help someone else too.

From the mn code in mn git: ovsk and ovs point to the same class of object OVSSwitch, "ovsk" is still existing for compatibility reason, but actually they are the same.

The missing piece of the puzzle is we need to add dcmd="/init" to our containernet topology as opposed to our base class.

For above problem, the following code will work- d2 = net.addDocker('d2', ip='10.0.2.15', dimage="lukaszlach/kali-desktop:xfce-top10",ports=[5900,6080],dcmd="/init , port_bindings={5900:5900,6080:6080},publish_all_ports= True, environment={"USER": "kali", "PASSWORD": "kali" , "ROOT_PASSWORD": "root"})

If you want to call the method as addLink(s7, h6, bw=10, delay=5ms), then you could create the links by using: