lwIP python bindings

Summary

The project provides python bindings for lwIP portable network stack along with the environment to deploy the stack in the user space.

The project status is 'Proof of concept/Work in progress'.

It was originally intended to be a study case for ctypes workshop but the outcome can be potentially used for several side purposes:

• to be os-independent test-bed for lwIP stack;
• deploy the stack in user space and use it on top of Api for unconventional link-layers/hardware;
• experiment with and learn about lwIP stack and stack integration.

Currently the following features are available:

• loading of several instances of lwIP stack emulating separate network hosts;
• emulated user space ethernet bus providing communication between lwIP ethernet network interfaces;
• async Udp socket implementation on top of lwIP core api;
• ping (ICMP echo) functionality.

lwIP

lwIP is a portable network stack developed to be used in embedded systems. The stack itself is added into the source tree as a submodule and can be found in the folder lwip. To be used via ctypes it is built as a shared library. The build environment for the library is located in the folder lwip-lib.

Repository

The repository has submodules so it should be cloned accordingly:

git clone https://github.com/vvish/py-lwip.git
git submodule update --init --recursive

or shorter

git clone --recurse-submodules https://github.com/vvish/py-lwip.git

lwIP shared library

The Makefile in the root of the source tree has target to build the library:

make lwip-lib

Makefile

The Makefile also contains other targets that simplify installation of project dependencies and tooling.

To install prerequisites, recommended tools and the package itself in the editable mode the following command can be used:

make init

Example code

The file lwip_py/examples/examples.py contains some reference code for the framework. For example:

python3 lwip_py/examples/examples.py -tw -l lwip_lib/build/liblwip.so udp-ping-pong

will run script implementing UDP-datagram exchange and forward recorded traffic to wireshark via scapy (wireshark should be available in the system).

Contribution

As the project was originally intended as a reference everyone who is interested to learn more about ctypes and python in general or experiment with lwIP and network protocols is welcomed to use it and contribute.

Feedback in the form of change requests, defect tickets and PR-s is appreciated.

Please consider that the code is under development, provided 'as is' and no warranty is given.