pybatmesh

pybatmesh is a program to create a wireless mesh network for communicating with each other. It can be useful during an internet shutdown, or to join online classes with a group of laptops. It uses B.A.T.M.A.N. Advanced, an implementation of the B.A.T.M.A.N. routing protocol to communicate with peers.

WARNING: This program uses an unencrypted network. This means you do not get any more privacy or security than with an open WiFi network.

Features

• Select best network when multiple nodes have internet access (gateway mode)
• Detect insertion and removal of wifi adapters and reconfigure them
• Readable logs
• Supports rfkill

Requirements

• systemd-networkd v248 or greater
• Linux kernel with batman-adv v2021.0 or greater
• iwd for controlling the WiFi adapter
• python (tested on 3.9 and 3.10)
• python setuptools, for building and installing pybatmesh
• python-systemd, for logging to systemd journal
• dasbus, for communicating with iwd
• two or more machines with a WiFi adapter having ibss support, called nodes or peers
• batctl (optional, for debugging)
• python3-pip (for installing dasbus on Debian-based distributions)

Installing

This program is available in the AUR for Arch users. Users of other distributions will have to build manually.

Arch Linux

Install pybatmesh (or pybatmesh-git for the development version) from the AUR with your favourite helper:

yay -S pybatmesh

Optionally, setup systemd-resolved for DNS. Start pybatmesh when you need it.

Debian or Ubuntu

pybatmesh is not packaged for Debian or Ubuntu, so you will have to build and install it manually. Currently, only Debian bookworm (testing) and Ubuntu 21.10 comes with the required version of systemd. Therefore, pybatmesh requires Debian testing or Ubuntu 21.10 or greater to work.

Install the requirements from the repositories:

# batctl is optional
sudo apt install python3-pip python3-systemd python3-dasbus iwd batctl

Now follow the instructions in the manual installation section

Fedora

pybatmesh is not packaged for Fedora, so it should be installed manually. pybatmesh requires at least systemd v248, which is only available on Fedora 34 and above. python-setuptools support building rpms, which are the preferred way of installing software in Fedora. Follow the steps to install pybatmesh on Fedora:

# Install the build requirements
sudo dnf install python3-setuptools make git

# Clone the repo
git clone https://git.disroot.org/pranav/pybatmesh.git
cd pybatmesh

# Create an installable rpm from the source code
make rpm

# Now install it. This will also install the requirements
sudo dnf install dist/pybatmesh-$(python3 -m setup --version)-1.noarch.rpm

Manually

Verify that the requirements are of required versions.

# Should be greater than or equal to 2021.0
batctl -v

# 248 or greater
systemctl --version

# Atleast 4.4
uname -r

# >= 3.6
python3 --version

# Check for IBSS (ad-hoc) support in your WiFi firmware or driver
iw phy | grep -q join_ibss && echo "IBSS is supported" || echo "IBSS not supported"

Clone the pybatmesh repo and cd into it.

git clone https://git.disroot.org/pranav/pybatmesh.git
cd pybatmesh

Now, build and install pybatmesh:

make
sudo make install

After installing, reload systemd so that it detects the new service files:

sudo systemctl daemon-reload

To upgrade, clean the build files, update the repo and reinstall:

make clean
git pull
make
sudo make uninstall
sudo make install

This will keep the configuration files.

How to use

You need more than one machine running pybatmesh for the connection to work.

Start pybatmesh

Though pybatmesh can run from the command line, it was designed to be run as a systemd service. To start pybatmesh, do the command on all the nodes:

sudo systemctl start pybatmesh.service

This will start a mesh network and connect to all nodes. To test if it works, run sudo batctl n -w and check for nodes. If there are any nodes, your network is up. Press Ctrl+C to stop batctl.

Getting internet access

Connect an ethernet cable from a router to any of the nodes. Now restart pybatmesh on the node to set gateway_mode to server. Other nodes will take a minute or more to renew DHCP. You can optionally do this manually if you don't want the delay. To do this, type sudo networkctl renew bridge0 on all nodes.

Tethering via WiFi AP

If there are two adapters in a peer, pybatmesh will start a WiFi ap (also called WiFi hotspot) on one of them.

Connect two WiFi adapters on a node. Now an AP will be started on one of the adapters. Type pybatmesh --print-wifi to get the WiFi SSID and password.

If you had set up internet access on one of the nodes, internet can be accessed from the AP.

Running at boot

To run pybatmesh at boot, enable the service on all the nodes:

sudo systemctl enable pybatmesh.service

Now pybatmesh will start a mesh on every boot.

If you have NetworkManager enabled, which is the default in Ubuntu and Fedora, it should be disabled:

sudo systemctl disable NetworkManager.service

To stop running at boot, you should disable pybatmesh.service:

sudo systemctl disable pybatmesh.service

If you had disabled NetworkManager before, enable it:

sudo systemctl enable NetworkManager.service

Stopping the service

sudo systemctl stop pybatmesh iwd systemd-networkd systemd-resolved

If your distribution uses NetworkManager, starting pybatmesh.service will have stopped it. Start NetworkManager again:

sudo systemctl start NetworkManager.service

Configuration

pybatmesh comes with a sample configuration file /etc/pybatmesh/pybatmesh.conf.example. To change how the program behaves, copy it to /etc/pybatmesh/pybatmesh.conf and edit it:

sudo cp /etc/pybatmesh/pybatmesh.conf{.example,}
# Now edit the file with your favourite editor as root
gedit admin:/etc/pybatmesh/pybatmesh.conf

Also, you can change its behaviour every time you run it using arguments:

pybatmesh --help

Contributing or reporting bugs

See HACKING.md

How it works

There are three modes commonly supported by WiFi adapters - ap (WiFi hotspot), station (for joining WiFi networks) and ad-hoc (or ibss, for decentralised networks). There are other modes supported by some WiFi adapters too, like p2p (WiFi direct), but this program doesn't use them.

pybatmesh uses two modes - ad-hoc and ap, for connecting to the mesh. pybatmesh uses iwd to start an ad-hoc network and configures systemd-networkd to setup a BATMAN Advanced network. If there are two WiFi adapters connected to the machine, pybatmesh starts an ad-hoc on one of them and an ap on the other. You can use the ap for connecting mobile phones and other devices to the mesh network.

Read the code and the documentation in the code to learn the details. See the directory network to see how systemd-networkd configures the network.

Use cases

Online class

pybatmesh can be used to share connections to join online classes. You need at least one device with internet access if you are not using a program like Jami (see below).

Internet shutdown

You can communicate with neighbouring devices running pybatmesh, using services like IPFS, Jami, Briar Secure Scuttlebutt or similar software which can work on an intranet. They should be installed on your machine before your friendly democratic government announces an internet shutdown, since you cannot download and install them during a shutdown. When a shutdown occurs, enable pybatmesh and use the installed software to communicate with anyone within range.

Uninstalling

If you installed pybatmesh manually, use make uninstall to remove pybatmesh and its data files. This requires python pip to be installed.

# Uninstall the program, keeping the config files
sudo make uninstall
# Or, to uninstall and remove config files
sudo make purge

Similar projects

Many projects make setting up B.A.T.M.A.N. Advanced mesh networks with WiFi routers easier. They are easier to setup and are more configurable. But pybatmesh is different from them. It simplifies setting up mesh networks with laptops or computers, and was not made to work with routers.

The following projects does something similar to pybatmesh, but requires special devices or routers to work. If you live in an area where the materials are easily available, consider using them instead of pybatmesh.

• LibreMesh: framework for OpenWrt-based firmwares
• disaster.radio: solar-powered communications network

License

pybatmesh is free/libre/swatantra and open source software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

See LICENSE for the complete version of the license.