Merge pull request 'Set gateway mode automatically' (#18) from gateway into master

Reviewed-on: pranav/naxalnet#18

CHANGELOG.md

@@ -1,23 +1,28 @@
 # Changelog
 
-## [Unreleased][] - 2021-09-21
+## [Unreleased][] - 2021-10-08
 
 - Better error messages
+- Sets gateway mode automatically (to choose the best available
+  connection). **This might cause problems with nodes running previous
+  version of naxalnet** (#15)
+- Cleanup before exit
+- Closed #19
 
 ## [v0.4.0][] - 2021-09-20
 
 - naxalnet is now a daemon! naxalnet will reconfigure the WiFi network
-  every time a WiFi adapter is plugged in or removed
+  every time a WiFi adapter is plugged in or removed (#14)
 - **Logging**: logs to systemd journal when run from systemd, stderr
-  otherwise
+  otherwise (#13)
 - New dependency `python-systemd`
 - Fixed dependency order in systemd service
 - Added `--verbose` argument
 
 ## [v0.3.0][] - 2021-08-19
 
-- Support for arguments
+- Support for arguments (#11)
-- Configuration file support with fallback values
+- Configuration file support with fallback values (#11)
 - Made messages more readable
 - Improved documentation in docstrings
 - Changed default name of mesh network. **This will make naxalnet
@@ -26,15 +31,17 @@
 
 ## [v0.2.0][] - 2021-07-26
 
-- rfkill support
+- rfkill support (#9)
-- rewrite into python module
+- rewrite into python module (#5)
 
 ## [v0.1.0][] - 2021-06-19
 
-Initial python version. At first, this was a shell script. Than it was
+Rewrite to python. At first, this was a shell script. Then it was
 converted into a single python file that did just what the shell script
 used to do. The shell script was not given a version.
 
+- Closed #1 and #3
+
 [unreleased]: https://git.disroot.org/pranav/naxalnet/compare/v0.4.0...HEAD
 [v0.4.0]: https://git.disroot.org/pranav/naxalnet/compare/v0.3.0...v0.4.0
 [v0.3.0]: https://git.disroot.org/pranav/naxalnet/compare/v0.2.0...v0.3.0

HACKING.md

@@ -5,13 +5,12 @@ Everyone can [hack][] naxalnet. See below for how to hack.
 ## Reporting issues and suggesting ideas
 
 To report a bug or suggest an idea, create a new issue at
-<https://git.disroot.org/pranav/naxalnet/issues> with a
+<https://git.disroot.org/pranav/naxalnet/issues>
-relevant label.
 
 ## Improving documentation
 
 The README and HACKING.md needs to be more beginner friendly.
-See section below.
+See #20.
 
 ## Contribute code
 
@@ -26,6 +25,6 @@ Currently this program is only packaged for Arch Linux.
 naxalnet needs packages in GNU+Linux+systemd
 distributions such as Debian, Fedora, openSUSE,
 and nixos. If you know/like to package it in your distro,
-post to issue #6.
+post a message to issue #6.
 
 [hack]: https://catb.org/jargon/html/H/hack.html

MANIFEST.in

@@ -1,5 +0,0 @@
-include LICENSE
-include README.md
-include naxalnet.service
-include naxalnet.conf.example
-recursive-include systemd-networkd *

Makefile

@@ -1,27 +1,37 @@
-# This makefile uses setup.py under the hood.
+# This makefile uses setup.py under the hood. In debian, and therefore
-# In ubuntu, python and pip are symlinks to python2 and pip2, not
+# ubuntu, and in fedora, python and pip are symlinks to python2 and pip2,
-# python3. So we have to specify python as python3 by default.
+# not python3. So we have to specify python as python3 by default.
+
 PYTHON := python3
 PIP := pip3
+
+# This can be changed when creating a package for your POSIX distribution
 DESTDIR:= /
 
 all: build
 
+# Build only when naxalnet/__init__.py changes. We assume here that anyone
+# creating a new commit will first update the __version__ in
+# naxalnet/__init__.py
 build: naxalnet/__init__.py
 	$(PYTHON) setup.py build
 
-install: build
+install:
 	$(PYTHON) setup.py install --root="$(DESTDIR)" --optimize=1 --skip-build
 
 uninstall:
 	$(PIP) uninstall -y naxalnet
 	rm -rf /usr/share/naxalnet /usr/lib/systemd/system/naxalnet.service
-	@echo "The directory /etc/naxalnet was not removed." && \
+	@echo "make uninstall will not remove anything in /etc/naxalnet" && \
 	echo "Do 'sudo make purge' to remove it."
 
-# remove config files, like apt purge
+rpm:
+	$(PYTHON) setup.py bdist_rpm --requires python3-dasbus,python3-systemd,iwd,systemd-networkd
+
+# Remove config files, like apt purge. Purge should first do what
+# uninstall does, so we add uninstall as a dependency to this rule.
 purge: uninstall
 	rm -rf /etc/naxalnet
 
 clean:
-	rm -rf build naxalnet.egg-info **/__pycache__
+	rm -rf build *.egg-info **/__pycache__ dist

README.md

@@ -1,18 +1,15 @@
 # naxalnet
 
 **naxalnet** is a program to create a wireless mesh network for
-communicating with each other. It can be useful during an
+communicating with each other. It can be useful during an [internet
-[internet shutdown](#internet-shutdown), or to join
+shutdown](#internet-shutdown), or to join [online classes](#online-class)
-[online classes](#online-class) with a group of laptops.
+with a group of laptops. It uses [B.A.T.M.A.N. Advanced][batman-adv], an
-It uses [B.A.T.M.A.N. Advanced][batman-adv], an implementation
+implementation of the B.A.T.M.A.N. routing protocol to communicate with
-of the B.A.T.M.A.N. routing protocol to communicate with peers.
+peers. The name naxal comes from Naxalbari, a village in Darjeeling, West
-The name naxal comes from Naxalbari, a village in Darjeeling,
+Bengal.
-West Bengal.
 
-WARNING:
+**WARNING**: This program uses an **unencrypted** network. This means you do
-This program uses an **unencrypted** network. This means
+not get any more privacy or security than with an open WiFi network.
-you do not get any more privacy or security than with an open WiFi
-network.
 
 <!-- NOTE TO ACTIVISTS
 
@@ -27,23 +24,24 @@ well-being if you get arrested under a draconian national security law.
 -->
 <!-- UNCOMMENT WHEN NECESSARY
 
-**Disclaimer**:
+**Disclaimer**: In case you are either 1: a complete idiot; or 2: a member
-In case you are either 1) a complete idiot; or 2) a member of the saffron
+of the saffron brigade; or 3: both, please be aware that this project is
-brigade; or 3) both, please be aware that this project is not affiliated
+not affiliated with any human rights defenders or with anyone currently at
-with any human rights groups designated as "terrorist" groups in India.
+risk of death in overcrowded prisons.
 
-Using the name naxal does not imply any form of connection
+Using the name naxal in a program will not shake the foundations of
-with anyone currently at risk of death in overcrowded prisons.
+democracy nor affect the soverignty, unity or integrity of any
+nation-state. .
 
 -->
 
 ## Requirements
 
-- [systemd-networkd v248 or more][batman-systemd]
+- [systemd-networkd v248 or greater][batman-systemd]
-- Linux kernel with batman-adv module
+- Linux kernel with [batman-adv v2021.0][batman-systemd] or greater
 - [iwd][] for controlling the WiFi adapter
-- python3
+- python (tested only on 3.9)
-- python3-setuptools, for building and installing naxalnet
+- python setuptools, for building and installing naxalnet
 - [python-systemd][], for logging to systemd journal
 - [dasbus][], for communicating with iwd
 - two or more machines with a WiFi adapter having ibss support, called
@@ -53,8 +51,8 @@ with anyone currently at risk of death in overcrowded prisons.
 
 ## Installing
 
-This program is available in the AUR for Arch users. Building
+This program is available in the AUR for Arch users. Users of other
-manually for other distributions may not always work.
+distributions will have to build manually.
 
 ### Arch Linux
 
@@ -65,21 +63,17 @@ development version) from the AUR with your favourite helper:
 yay -S naxalnet
 ```
 
-Optionally, [setup systemd-resolved][arch-resolved] for DNS if any
+Optionally, [setup systemd-resolved][arch-resolved] for DNS. [Start
-of the nodes have internet access. [Start naxalnet][startnx] when
+naxalnet][startnx] when you need it.
-you need it.
 
-### Ubuntu
+### Debian or Ubuntu
 
-naxalnet is not packaged for Ubuntu, so you will have to build
+naxalnet is not packaged for Debian or Ubuntu, so you will have to build
-and install it manually.
+and install it manually. Currently, only Debian experimental and Ubuntu
-Currently, only the **unreleased 21.10** comes with the
+21.10 comes with the required version of systemd. Therefore, naxalnet
-required version of systemd. Therefore, naxalnet **won't work on Ubuntu
+requires **Debian experimental** or **Ubuntu 21.10 or greater** to work.
-21.04 or older**.
 
-<!-- TODO: remove this message if systemd 248 arrives in 21.04 -->
+Install the requirements from the repositories:
-
-Install the requirements from the Ubuntu repositories:
 
 ```sh
 # batctl is optional
@@ -93,20 +87,47 @@ Now follow the instructions in the
 
 ### Fedora
 
-naxalnet is not packaged for Fedora, so it should be installed
+naxalnet is not packaged for Fedora, so it should be installed manually.
-manually. naxalnet requires atleast systemd v248 which is only
+naxalnet requires atleast systemd v248, which is only available on **Fedora
-available on **Fedora 34 and above**. Install the dependencies:
+34 and above**. python-setuptools support building rpms, which are the
+preferred way of installing software in Fedora. Follow the steps to
+install naxalnet on Fedora:
 
 ```sh
-# systemd-resolved may be required for rawhide
+# Install the build requirements
-sudo dnf install systemd-networkd iwd python3-dasbus python3-setuptools python3-systemd
+sudo dnf install python3-setuptools make git
-```
 
-Now head over to the [next section][install-manual] to install naxalnet.
+# Clone the repo
+git clone https://git.disroot.org/pranav/naxalnet.git
+cd naxalnet
+
+# Create an installable rpm from the source code
+make rpm
+
+# Now install it. This will also install the requirements
+sudo dnf install dist/naxalnet-$(python3 -m setup --version)-1.noarch.rpm
+```
 
 ### Manually
 
-Install the [requirements][requirements].
+Verify that the [requirements][] are of required versions.
+
+```sh
+# 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 -iq ibss && echo "IBSS is supported" || echo "IBSS not supported"
+```
 
 Clone the naxalnet repo and cd into it.
 
@@ -135,7 +156,8 @@ To upgrade, clean the build files, update the repo and reinstall:
 make clean
 git pull
 make
-sudo make uninstall install
+sudo make uninstall
+sudo make install
 ```
 
 This will keep the configuration files.
@@ -154,15 +176,16 @@ To start naxalnet, do the command on all the nodes:
 sudo systemctl start naxalnet.service
 ```
 
-This will start a mesh network and connect to all nodes.
+This will start a mesh network and connect to all nodes. To test if it
-To test if it works, run `sudo batctl n -w` and check for
+works, run `sudo batctl n -w` and check for nodes. If there are any nodes,
-nodes. If there are any nodes, your network is up. Press
+your network is up. Press Ctrl+C to stop `batctl`.
-Ctrl+C to stop `batctl`.
 
 ### Getting internet access
 
-Connect an ethernet cable from a router to any of the nodes and
+Connect an ethernet cable from a router to any of the nodes. Now restart
-renew the DHCP connection of all peers. To do this, type
+naxalnet 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
@@ -186,12 +209,26 @@ sudo systemctl enable naxalnet.service
 ```
 
 Now naxalnet will start a mesh on every boot.
-Disable the service to stop running at boot:
+
+If you have NetworkManager enabled, which is the default in Ubuntu and
+Fedora, it should be disabled:
+
+```sh
+sudo systemctl disable NetworkManager.service
+```
+
+To stop running at boot, you should disable `naxalnet.service`:
 
 ```sh
 sudo systemctl disable naxalnet.service
 ```
 
+If you had disabled `NetworkManager` before, enable it:
+
+```sh
+sudo systemctl enable NetworkManager.service
+```
+
 ### Stopping the service
 
 ```sh
@@ -224,6 +261,10 @@ arguments:
 naxalnet --help
 ```
 
+## Contributing or reporting bugs
+
+See [HACKING.md](HACKING.md)
+
 ## How it works
 
 There are three modes commonly supported by WiFi adapters - `ap` (WiFi
@@ -262,10 +303,11 @@ Withheld due to national security reasons.
 
 You can communicate with neighbouring devices running naxalnet, using
 services like [IPFS][], [Jami][], [Secure Scuttlebutt][ssb] and others
-which can work on an intranet. They should be installed on your
+which can work on an intranet. They should be installed on your machine
-machine _before_ your friendly democratic government announces an
+_before_ your friendly democratic government announces an [internet
-[internet shutdown][], since you cannot download and install them
+shutdown][], since you cannot download and install them during a shutdown.
-during a shutdown. When a shutdown occurs, [enable naxalnet][enablenx].
+When a shutdown occurs, [enable naxalnet][enablenx] and use the installed
+software to communicate with anyone within range.
 
 ## Uninstalling
 
@@ -279,10 +321,6 @@ sudo make uninstall
 sudo make purge
 ```
 
-## Contributing or reporting bugs
-
-See [HACKING.md](HACKING.md)
-
 ## Similar projects
 
 Many projects make setting up B.A.T.M.A.N. Advanced mesh networks with

naxalnet.conf.example

@@ -11,6 +11,19 @@ confdir = /usr/share/naxalnet/networkd
 # See man:systemd.network(5)
 runtimedir = /run/systemd/network
 
+[device]
+# These are better left this way
+# Changing this won't do you any good, unless you have
+# other network configs that would mess things up.
+batman=bat0
+bridge=bridge0
+
+[gateway]
+# This helps users choose the best network when multiple machines
+# offer an internet connection, or to be more precise, a DHCP server
+# Allowed values: auto, server, client or off
+mode=auto
+
 [adhoc]
 # All your nodes should have the same name
 name = NxMesh
@@ -20,4 +33,3 @@ name = NxMesh
 ssid = MeshWiFi
 # Note the spelling. It's passwd, not password.
 passwd = naxalnet256
-

naxalnet.service

@@ -21,16 +21,8 @@ Type=notify
 NotifyAccess=all
 Restart=on-failure
 RestartSec=2sec
-ExecStart=/usr/bin/naxalnet --systemd
+ExecStart=naxalnet --systemd
-# Reload systemd-networkd after naxalnet signals it is ready
+KillSignal=SIGINT
-ExecStartPost=/usr/bin/networkctl reload
-# When naxalnet exits, delete all files starting
-# with mesh.* in /run/systemd/network
-ExecStopPost=/usr/bin/find /run/systemd/network -type f -delete -name "mesh.*"
-# Then delete the two interfaces created...
-ExecStopPost=/usr/bin/networkctl delete bridge0 bat0
-# ... and reload the configuration files.
-ExecStopPost=/usr/bin/networkctl reload
 # naxalnet already logs to systemd journal so we don't need
 # stdout and stderr.
 StandardOutput=null

naxalnet/__init__.py

@@ -1,25 +1,32 @@
 # This file is part of naxalnet.
 # Copyright (C) 2021 The naxalnet Authors
 
-# This program is free software: you can redistribute it and/or modify
+# This program is free software: you can redistribute it and/or modify it
-# it under the terms of the GNU General Public License as published by
+# under the terms of the GNU General Public License as published by the
-# the Free Software Foundation, either version 3 of the License, or
+# Free Software Foundation, either version 3 of the License, or (at your
-# (at your option) any later version.
+# option) any later version.
 
-# This program is distributed in the hope that it will be useful,
+# This program is distributed in the hope that it will be useful, but
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-# GNU General Public License for more details.
+# Public License for more details.
 
-# You should have received a copy of the GNU General Public License
+# You should have received a copy of the GNU General Public License along
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
 naxalnet
 ========
 
 Create mesh networks with batman-adv, systemd-networkd and iwd.
-See README.md for documentation.
+
+See README.md and the docstrings for documentation. You can read
+documentaion in the python interpretor using something like the example
+given below.
+
+>>> help("naxalnet")
+>>> help("naxalnet.config")
+
 """
 
 # GUIDE FOR CHANGING __version__
@@ -35,4 +42,4 @@ See README.md for documentation.
 #
 # In case you forgot to change the version, skip the number
 # and put the next number in the next commit.
-__version__ = "0.4.0a1"
+__version__ = "0.4.0a6"

naxalnet/__main__.py

@@ -16,9 +16,16 @@
 
 
 """
+__main__.py
+-----------
+
 If called as python -m naxalnet, this file makes naxalnet run like
 it was called from the commandline. Try:
     python -m naxalnet --help
+
+WARNING: Using naxalnet might threaten the soverignity and integrity of
+your nation-state. The authors are not responsible for any damage caused
+while using this software.
 """
 
 from naxalnet.scripts import main

naxalnet/config.py

@@ -1,59 +1,56 @@
 # This file is part of naxalnet.
 # Copyright (C) 2021 The naxalnet Authors
 
-# This program is free software: you can redistribute it and/or modify
+# This program is free software: you can redistribute it and/or modify it
-# it under the terms of the GNU General Public License as published by
+# under the terms of the GNU General Public License as published by the
-# the Free Software Foundation, either version 3 of the License, or
+# Free Software Foundation, either version 3 of the License, or (at your
-# (at your option) any later version.
+# option) any later version.
 
-# This program is distributed in the hope that it will be useful,
+# This program is distributed in the hope that it will be useful, but
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-# GNU General Public License for more details.
+# Public License for more details.
 
-# You should have received a copy of the GNU General Public License
+# You should have received a copy of the GNU General Public License along
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
 config.py
 ---------
 
-This file contains functions to parse configuration files
+This file contains functions to parse configuration files and arguments.
-and arguments. Most of these functions are meant to be used
+Most of these functions are meant to be used by parse_args() internally,
-by parse_args() internally, so only parse_args() should
+so only parse_args() should be imported outside this file.
-be imported outside this file.
 
-Some parts of naxalnet can be configured by configuration
+Some parts of naxalnet can be configured by configuration files and
-files and arguments. First, the default values from
+arguments in a specific order. First, the default values from default.py
-default.py is taken. Then, key-value pairs from the
+is taken. Then, key-value pairs from the configuration files are read, if
-configuration files are read, if they exist, in the
+they exist, in the following order:
-following order:
+
+- First it reads /usr/share/naxalnet/naxalnet.conf and then from
+  /usr/share/naxalnet/naxalnet.conf.d/*.conf where *.conf means any file
+  with the name ending with ".conf". The files in this directory are
+  intended to be used by distribution and package maintainers.
 
-- First it reads /usr/share/naxalnet/naxalnet.conf
-  and then from /usr/share/naxalnet/naxalnet.conf.d/*.conf
-  where *.conf means any file with the name ending with
-  ".conf". The files in this directory are intended
-  to be used by distribution and package maintainers.
 - Next, it does the same with /usr/local/share/naxalnet
-- Then, it looks for the files naxalnet.conf and
-  naxalnet.conf.d/*.conf from the directory
-  /etc/naxalnet, like it did up above. This directory is where
-  the user creates and stores the config file.
-- Then it parses the arguments from the commandline,
-  storing the values in the files parsed until now
-  as fallback. Finally you get an argpase.Namespace object
-  from parse_args().
-  Because of the way this is implemented, all key-value
-  pairs in the configuration should have an argument
-  too, or they won't be parsed.
 
-All the key-value pairs are replaced successively if they exist
+- Then, it looks for the files naxalnet.conf and naxalnet.conf.d/*.conf
-by each new configuration file parsed, similar
+  from the directory /etc/naxalnet, like it did up above. This directory
-to how systemd parses configuration and service files.
+  is where the user creates and stores the config file.
-If any of the files checked does not exist, then they are
+
-ignored and the next combination is checked. If none of
+- Then it parses the arguments from the commandline, storing the values in
-the config files exist and no arguments are given, the
+  the files parsed until now as fallback. Finally you get an
-fallback data from default.py is used.
+  argpase.Namespace object from parse_args(). Because of the way this is
+  implemented, all key-value pairs in the configuration should have an
+  argument too, or they won't be parsed.
+
+All the key-value pairs are replaced successively if they exist by each
+new configuration file parsed, similar to how systemd parses configuration
+and service files. If any of the files checked does not exist, then they
+are ignored and the next combination is checked. If none of the config
+files exist and no arguments are given, the fallback data from default.py
+is used.
+
 """
 
 from pathlib import Path
@@ -158,6 +155,24 @@ def parse_args() -> Namespace:
         help="send log messages to systemd journal",
     )
 
+    parser.add_argument(
+        "--batman-device",
+        default=config["device"]["batman"],
+        help="name of interface used by batman-adv",
+    )
+
+    parser.add_argument(
+        "--bridge-device",
+        default=config["device"]["bridge"],
+        help="name of bridge interface",
+    )
+
+    parser.add_argument(
+        "--gateway-mode",
+        default=config["gateway"]["mode"],
+        help="auto, server, client, or off",
+    )
+
     parser.add_argument(
         "--version",
         "-V",
@@ -170,8 +185,10 @@ def parse_args() -> Namespace:
         "-v", "--verbose", action="count", default=0, help="increase output verbosity"
     )
 
-    # logger.debug("Parsing arguments")
     return parser.parse_args()
 
 
+# This is defined here because log.py needs some arguments to determine
+# the loglevel and where to send the log message to. If you know a better
+# way of implementing it, create an issue
 args = parse_args()

naxalnet/daemon.py

@@ -1,24 +1,25 @@
 # This file is part of naxalnet.
 # Copyright (C) 2021 The naxalnet Authors
 
-# This program is free software: you can redistribute it and/or modify
+# This program is free software: you can redistribute it and/or modify it
-# it under the terms of the GNU General Public License as published by
+# under the terms of the GNU General Public License as published by the
-# the Free Software Foundation, either version 3 of the License, or
+# Free Software Foundation, either version 3 of the License, or (at your
-# (at your option) any later version.
+# option) any later version.
 
-# This program is distributed in the hope that it will be useful,
+# This program is distributed in the hope that it will be useful, but
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-# GNU General Public License for more details.
+# Public License for more details.
 
-# You should have received a copy of the GNU General Public License
+# You should have received a copy of the GNU General Public License along
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
 daemon.py
 ---------
 
-The daemon part. This is currently under construction.
+The daemon part. This is used to perform some work when a new wifi adapter
+is plugged in, or it is removed.
 """
 
 from dasbus.loop import EventLoop
@@ -32,13 +33,14 @@ class Daemon:
     def __init__(self):
         self.loop = EventLoop()
         self.iwd = IWD()
+        self.callback = None
 
     def on_device_add(self, path, data):
         """
         this function will be run every time a device is added
         """
         if IWD_DEVICE_INTERFACE in data:
-            logger.debug("New device %s found", str(data[IWD_DEVICE_INTERFACE]["Name"]))
+            logger.debug("New device %s found", data[IWD_DEVICE_INTERFACE]["Name"])
             logger.info("Reloading")
             self.callback()
 

naxalnet/default.py

@@ -1,29 +1,28 @@
 # This file is part of naxalnet.
 # Copyright (C) 2021 The naxalnet Authors
 
-# This program is free software: you can redistribute it and/or modify
+# This program is free software: you can redistribute it and/or modify it
-# it under the terms of the GNU General Public License as published by
+# under the terms of the GNU General Public License as published by the
-# the Free Software Foundation, either version 3 of the License, or
+# Free Software Foundation, either version 3 of the License, or (at your
-# (at your option) any later version.
+# option) any later version.
 
-# This program is distributed in the hope that it will be useful,
+# This program is distributed in the hope that it will be useful, but
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-# GNU General Public License for more details.
+# Public License for more details.
 
-# You should have received a copy of the GNU General Public License
+# You should have received a copy of the GNU General Public License along
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
 default.py
 ----------
 
-This file contains default values for configuration.
+This file contains default values for configuration. This is taken as
-This is taken as fallback data by config.py if no
+fallback data by config.py if no configuration files were found, or if a
-configuration files were found, or if a key-value pair
+key-value pair was not present in the config file. The data will be
-was not present in the config file. The data will be
+further changed by arguments if naxalnet is called from the commandline.
-further changed by arguments if naxalnet is called
+See config.py for more info.
-from the commandline. See config.py for more info.
 """
 
 CONFIG = {
@@ -31,13 +30,17 @@ CONFIG = {
         "confdir": "/usr/share/naxalnet/networkd",
         "runtimedir": "/run/systemd/network",
     },
+    "device": {"batman": "bat0", "bridge": "bridge0"},
     "adhoc": {"name": "NxMesh"},
     "ap": {"ssid": "MeshWiFi", "passwd": "naxalnet256"},
+    "gateway": {"mode": "auto"},
 }
 
 # glob
 CONFIG_FILES = ["naxalnet.conf", "naxalnet.conf.d/*.conf"]
 CONFIG_DIRS = ["/usr/share/naxalnet", "/usr/local/share/naxalnet", "/etc/naxalnet"]
+MESH_GLOB = "mesh.*"
+TMP_NET_GLOB = "tmp.*"
 
 ISSUE_URL = "https://git.disroot.org/pranav/naxalnet/issues"
 REPORT_BUG_INFO = "If you think this is a bug, report it to " + ISSUE_URL

naxalnet/iwd.py

@@ -1,60 +1,54 @@
 # This file is part of naxalnet.
 # Copyright (C) 2021 The naxalnet Authors
 
-# This program is free software: you can redistribute it and/or modify
+# This program is free software: you can redistribute it and/or modify it
-# it under the terms of the GNU General Public License as published by
+# under the terms of the GNU General Public License as published by the
-# the Free Software Foundation, either version 3 of the License, or
+# Free Software Foundation, either version 3 of the License, or (at your
-# (at your option) any later version.
+# option) any later version.
 
-# This program is distributed in the hope that it will be useful,
+# This program is distributed in the hope that it will be useful, but
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-# GNU General Public License for more details.
+# Public License for more details.
 
-# You should have received a copy of the GNU General Public License
+# You should have received a copy of the GNU General Public License along
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
 iwd.py
 ------
 
-This file contains methods to communicate with iwd via
+This file contains methods to communicate with iwd via its D-Bus API and
-its D-Bus API and control WiFi adapters.
+control WiFi adapters.
 
-Some terms used here, such as device and adapter might
+Some terms used here, such as device and adapter might confuse you if you
-confuse you if you haven't used iwctl before.
+haven't used iwctl before. Just as a quick reference, here is a list of
-Just as a quick reference, here is a list of terms
+terms and what they mean:
-and what they mean:
 
-- ad-hoc: a mode supported by some WiFi adapters to
+- ad-hoc: a mode supported by some WiFi adapters to start a decentralised
-          start a decentralised network, where there
+          network, where there is no central point of failure.
-          is no central point of failure.
 
-- ap: a mode used to start a central access point
+- ap: a mode used to start a central access point so that other machines
-      so that other machines without naxalnet can
+      without naxalnet can connect to the mesh. AP is also known as WiFi
-      connect to the mesh. AP is also known as
+      hotspot.
-      WiFi hotspot.
 
-- station: this is the mode most WiFi adapters use
+- station: this is the mode most WiFi adapters use by default. This mode
-           by default. This mode is used to connect to
+           is used to connect to an ap. naxalnet DOES NOT use this mode.
-           an ap. naxalnet DOES NOT use this mode.
 
-- adapter: a physical WiFi chip or something similar
+- adapter: a physical WiFi chip or something similar that is present
-           that is present inside most laptops and phones
+           inside most laptops and phones or can be connected via USB to a
-           or can be connected via USB to a machine.
+           machine.
 
-- device: an interface provided by the kernel to control
+- device: an interface provided by the kernel to control an adapter. Some
-          an adapter. Some adapters can have multiple
+          adapters can have multiple devices so that you can start an ap
-          devices so that you can start an ap on one device
+          on one device and an ad-hoc on the other. By default, iwd starts
-          and an ad-hoc on the other. By default, iwd starts
           only one device each for one adapter.
 
-- machine: Since iwd uses the term device for a
+- machine: Since iwd uses the term device for a WiFi interface, we use the
-           WiFi interface, we use the word machine to
+           word machine to refer to a computer, or a laptop, or a phone.
-           refer to a computer, or a laptop, or a phone.
 
-- node: a machine that runs naxalnet and is therefore
+- node: a machine that runs naxalnet and is therefore connected to the
-        connected to the mesh.
+        mesh.
 """
 
 from dasbus.connection import SystemMessageBus
@@ -74,7 +68,7 @@ class IWD:
     """Manage iwd via dbus"""
 
     def __init__(self, bus=SystemMessageBus()):
-        # self._bus and self._proxy are meant for use only in this file
+        # self._bus and self._proxy are meant for use only in this submodule
         self._bus = bus
         self.reload()
 
@@ -95,9 +89,9 @@ class IWD:
         for i in device_paths:
             proxy = self._bus.get_proxy(IWD_BUS, i)
             if proxy.Name == name:
-                return i
+                # See comment in the function below
-            # If no devices were found, return None
+                path = i
-        return None
+        return path
 
     def get_adapter_path_from_name(self, name: str) -> str:
         """returns path of adapter as str"""
@@ -105,9 +99,10 @@ class IWD:
         for i in adapter_paths:
             proxy = self._bus.get_proxy(IWD_BUS, i)
             if proxy.Name == name:
-                return i
+                # We could have just used return here, but shutting up
-            # If no adapters were found
+                # pylint has a greter priority at the moment
-        return None
+                path = i
+        return path
 
     def get_all_device_paths(self) -> list:
         """returns list of paths of all devices"""
@@ -132,7 +127,8 @@ class IWD:
 
     def get_devices(self) -> list:
         """
-        returns list of device names as str
+        returns list of all device names as str
+
         example: ["wlan0", "wlan1"]
         """
         devices = []
@@ -146,6 +142,7 @@ class IWD:
     def get_adapters(self) -> list:
         """
         returns list of adapters
+
         example: ["phy0","phy1"]
         """
         adapters = []
@@ -160,6 +157,7 @@ class IWD:
 class Device:
     """
     control devices with iwd
+
     name: name of device (str)
     adapter: name of adapter (str)
     """
@@ -190,7 +188,10 @@ class Device:
         self.reload()
 
     def reload(self):
-        """reload the proxy after changing mode"""
+        """
+        Reload the proxy. Used liberally by other
+        members to work around errors
+        """
         self._proxy = self._bus.get_proxy(IWD_BUS, self._path)
         self.name = self._proxy.Name
         adapter_path = self._proxy.Adapter
@@ -235,16 +236,15 @@ class Device:
         if it isn't already on ad-hoc and power onn the device
         if it is off
         """
-        print("Starting adhoc", name)
+        # Stop adhoc if already started
+        self.stop_adhoc()
+
         if self.get_mode() != "ad-hoc":
             self.set_mode("ad-hoc")
 
         if not self.is_powered_on():
             self.power_on()
 
-        # Stop adhoc if already started
-        self.stop_adhoc()
-
         logger.debug("Starting ad-hoc on %s", self.name)
         self._proxy.StartOpen(name)
 
@@ -261,15 +261,16 @@ class Device:
         if it isn't already on ap and turning
         on the device if it is off
         """
+
+        # Stop ap if already started
+        self.stop_ap()
+
         if self.get_mode() != "ap":
             self.set_mode("ap")
 
         if not self.is_powered_on():
             self.power_on()
 
-        # Stop ap if already started
-        self.stop_ap()
-
         logger.debug("Starting ap on %s with ssid %s", self.name, ssid)
         self._proxy.Start(ssid, passwd)
 

naxalnet/log.py

@@ -18,8 +18,9 @@
 log.py
 ------
 
-Initialise the logger for other submodules to import. Do not
+Initialise the logger for other submodules to import. Do not import any
-import any submodules here except for naxallnet.config
+submodules here other than naxallnet.config, which is needed to set the
+loglevel and to add the systemd journal handler
 """
 import logging
 from systemd.journal import JournalHandler

naxalnet/network.py

@@ -0,0 +1,120 @@
+# This file is part of naxalnet.
+# Copyright (C) 2021 The naxalnet Authors
+
+# This program is free 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.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+network.py
+----------
+
+This submodule manages the systemd-networkd configuration. This is used to
+add configuration files to the systemd-networkd runtime directory.
+
+Some configuration files have variables which should be substituted by
+str.format() in python. The values for these variables can be set using
+NetworkD.set_vars(). See files in the systemd-networkd directory for
+examples.
+"""
+
+import subprocess
+from pathlib import Path
+from dasbus.connection import SystemMessageBus
+
+
+NETWORKD_BUS = "org.freedesktop.network1"
+NETWORKD_PATH = "/org/freedesktop/network1"
+
+
+class NetworkD:
+    """
+    Control systemd-networkd using configuration files. Since these
+    were made for use by naxalnet only, the class is not suitable for
+    importing outside naxalnet.
+    """
+
+    def __init__(self, runtime_dir="/run/systemd/network", bus=SystemMessageBus()):
+        self._bus = bus
+        self.proxy_reload()
+
+        self.variables = {}
+        self.runtime_path = Path(runtime_dir)
+        # Create the runtime directory if it doesn't exist
+        self.runtime_path.mkdir(parents=True, exist_ok=True)
+
+    def set_vars(self, **variables):
+        """set the variables to replace with str.format"""
+        self.variables = variables
+
+    def proxy_reload(self) -> None:
+        """reload the proxy"""
+        self.proxy = self._bus.get_proxy(NETWORKD_BUS, NETWORKD_PATH)
+
+    def reload(self) -> None:
+        """
+        Reload the systemd-networkd configuration. This is used by many
+        class methods after doing their job.
+        """
+        self.proxy.Reload()
+
+    def add_config(self, name: str) -> None:
+        """add config file to runtime directory and reload networkd"""
+        source = Path(name)
+        destination = self.runtime_path / source.name
+
+        # Substitute variables in the config
+        text = source.read_text(encoding="utf-8").format(**self.variables)
+        # now write it to a runtime config of the same name
+        destination.write_text(text, encoding="utf-8")
+        self.reload()
+
+    def is_routable(self) -> bool:
+        """returns true if any interface is routable"""
+        return self.proxy.AddressState == "routable"
+
+    def delete_interface(self, name: str) -> None:
+        """delete the given interface"""
+        # If anyone knows a better way of doing this, create
+        # an issue and get things done
+        subprocess.run(["networkctl", "delete", name], check=True)
+        # This is probably not required. This is mainly to shut up
+        # pylint's messages
+        self.reload()
+
+    def disable_config(self, name: str) -> None:
+        """
+        Disable or mask the config of the same name. This can only be
+        used for configs in /usr/lib/systemd/network and
+        /usr/local/lib/systemd/network. It works on the same principle
+        used by systemctl mask, that is, it created a symlink of the same
+        name in the runtime directory and links it to /dev/null.
+        """
+        path = self.runtime_path / name
+        path.symlink_to("/dev/null")
+        self.reload()
+
+    def remove_config(self, name: str) -> None:
+        """
+        remove the file called 'name' from the runtime dir and reload
+        """
+        path = self.runtime_path / name
+        path.unlink()
+        self.reload()
+
+    def remove_all_configs(self) -> None:
+        """
+        Remove all configs in runtime_path. This will remove all files
+        in runtime_path without checking who put them there.
+        """
+        for i in self.runtime_path.iterdir():
+            self.remove_config(i.name)

naxalnet/scripts.py

@@ -27,39 +27,80 @@ When run from the commandline, the function main() is called.
 """
 
 import sys
+import time
 from pathlib import Path
-from shutil import copy
 from dasbus.error import DBusError
 from systemd.daemon import notify
 from naxalnet import __version__
-from naxalnet.default import REPORT_BUG_INFO
+from naxalnet.default import REPORT_BUG_INFO, MESH_GLOB, TMP_NET_GLOB
 from naxalnet.log import logger
 from naxalnet.iwd import Adapter, Device, IWD
 from naxalnet.config import args
 from naxalnet.daemon import Daemon
+from naxalnet.network import NetworkD
 
 
-def copy_files():
+def get_sorted_glob(directory: str, glob: str) -> list:
+    """return sorted list of filenames matching glob"""
+    path = Path(directory)
+    glob_list = path.glob(glob)
+    sorted_list = []
+    for i in glob_list:
+        # g is a list of PosixPath objects.
+        # So we add their absolute path as str.
+        sorted_list.append(str(i))
+    # sorted_list is not sorted, so we sort them here
+    sorted_list.sort()
+    return sorted_list
+
+
+def any_interface_is_routable():
+    """returns true if any of the interfaces is routable"""
+    networkd = NetworkD(runtime_dir=args.networkd_runtime_dir)
+
+    # First, add the temporary configs to networkd.
+    for i in get_sorted_glob(args.networkd_config_dir, TMP_NET_GLOB):
+        logger.debug("Adding temporary config %s", i)
+        networkd.add_config(i)
+    # Then, wait for some time to setup the network.
+    # This can probably be replaced by a d-bus wait-for-signal
+    # function that timeouts after 10 seconds.
+    time.sleep(10)
+    routable = networkd.is_routable()
+    networkd.remove_all_configs()
+
+    return routable
+
+
+def setup_mesh(gateway_mode: str = "off"):
     """
-    Copy networkd configs to volatile dir.
+    configure networkd to setup the mesh
-    The D-Bus API does not support creating new interfaces
+
-    or linking to bridges. So we use config files.
+    gateway_mode can be client, server, or off
-    See man:systemd.network(5)
     """
     try:
         notify("STATUS=Configuring the network...")
         logger.info("Copying network config files")
-        dest = Path(args.networkd_runtime_dir)
-        src = Path(args.networkd_config_dir)
 
-        # Create the volatile directory if it doesn't exist
+        networkd = NetworkD(runtime_dir=args.networkd_runtime_dir)
-        dest.mkdir(parents=True, exist_ok=True)
+        networkd.set_vars(
+            batdev=args.batman_device,
+            bridgedev=args.bridge_device,
+            gateway_mode=gateway_mode,
+        )
 
-        # Copy all files in src to dest
+        # Fix for issue #19. There should be a switch to disable this
-        for i in src.iterdir():
+        # humanitarian intervention. We don't want to adopt the U.S.
-            copy(i, dest)
+        # foreign policy here.
+        networkd.disable_config("80-wifi-adhoc.network")
+
+        for i in get_sorted_glob(args.networkd_config_dir, MESH_GLOB):
+            logger.debug("Adding network config %s", i)
+            networkd.add_config(i)
     except PermissionError:
-        logger.exception("A PermissionError occured while copying files")
+        logger.exception(
+            "A PermissionError occured while copying files. Make sure you are root."
+        )
         logger.error(REPORT_BUG_INFO)
         sys.exit(3)
     except:
@@ -111,8 +152,10 @@ def setup_devices():
             if not adhoc_adapter.is_powered_on():
                 logger.debug("Adapter %s is off. Turning on", adhoc_adapter.name)
                 adhoc_adapter.power_on()
+
             logger.info("Starting mesh on %s", adhoc_device.name)
             adhoc_device.start_adhoc_open(args.adhoc_name)
+
             # Start Access point if ap_device is not empty,
             # ie, we have more devices
             if len(ap_devices) != 0:
@@ -138,11 +181,30 @@ def setup_devices():
         logger.error(REPORT_BUG_INFO)
         sys.exit(4)
     except:
-        logger.exception("An unknow error occured while setting up the mesh")
+        logger.exception("An unknown error occured while setting up the mesh")
         logger.error(REPORT_BUG_INFO)
         sys.exit(4)
 
 
+def cleanup():
+    """
+    Remove all network config, poweroff used wireless devices and
+    exit with 0.
+    """
+    networkd = NetworkD(runtime_dir=args.networkd_runtime_dir)
+    logger.info("Exiting gracefully")
+    networkd.remove_all_configs()
+    for i in IWD().get_devices():
+        logger.debug("Turning off %s", i)
+        device = Device(i)
+        # device.set_mode("station")
+        device.power_off()
+    logger.debug("Deleting interface %s", args.batman_device)
+    networkd.delete_interface(args.batman_device)
+    logger.debug("Deleting interface %s", args.bridge_device)
+    networkd.delete_interface(args.bridge_device)
+
+
 def print_wifi():
     """
     Prints the name and password of the adhoc, and ap
@@ -171,20 +233,40 @@ def main():
     elif args.version:
         print_version()
         sys.exit(0)
-    copy_files()
 
-    setup_devices()
     # Notify systemd that naxalnet is ready.
     # see man:sd_notify(3)
     notify("READY=1")
 
-    # Start the daemon so that setup_devices() is called every
+    # Gateway mode comes in handy when many nodes have a DHCP server and
-    # time a device is connected or removed.
+    # you want to prevent conflicts. It defaults to "auto" in naxalnet.
-    daemon = Daemon()
+    # https://www.open-mesh.org/projects/batman-adv/wiki/Gateways
-    daemon.add_callback(setup_devices)
+    if args.gateway_mode == "auto":
+        logger.info("Checking for internet connection")
+        notify("STATUS=Checking for internet")
+        # If any interface is routable, set gateway mode to server
+        if any_interface_is_routable():
+            gateway_mode = "server"
+        else:
+            gateway_mode = "client"
+        logger.info("gateway_mode set to %s", gateway_mode)
+    elif args.gateway_mode in ["server", "client", "off"]:
+        gateway_mode = args.gateway_mode
+    else:
+        logger.error("gateway-mode has an illegal value")
+        sys.exit(5)
 
-    notify("STATUS=Waiting for changes")
+    try:
-    daemon.start()
+        setup_devices()
+        setup_mesh(gateway_mode=gateway_mode)
 
-    # naxalnet prints Bye while exiting.
+        # Start the daemon so that setup_devices() is called every
-    logger.info("Bye")
+        # time a device is connected or removed.
+        daemon = Daemon()
+        daemon.add_callback(setup_devices)
+
+        notify("STATUS=Waiting for changes")
+        daemon.start()
+    # systemd uses SIGINT to kill this program
+    except KeyboardInterrupt:
+        cleanup()

setup.cfg

@@ -1,3 +1,4 @@
+# This program is not meant to be distributed through PyPi
 [metadata]
 name = naxalnet
 version = attr: naxalnet.__version__
@@ -34,7 +35,7 @@ console_scripts =
 lib/systemd/system =
     naxalnet.service
 # If installing with pip, this file will be copied to some other place.
-# This is the reason we use setup.py instead of pip.
+# This is the reason we use setup.py instead of pip in the Makefile.
 /etc/naxalnet =
     naxalnet.conf.example
 share/naxalnet/networkd =
@@ -45,3 +46,4 @@ share/naxalnet/networkd =
     systemd-networkd/mesh.05-wireless-ap.network
     systemd-networkd/mesh.06-eth.network
     systemd-networkd/mesh.07-bridge.network
+    systemd-networkd/tmp.01-eth.network

systemd-networkd/mesh.01-batman.netdev

@@ -1,10 +1,13 @@
 # Create the BATMAN interface
-# See 04-batman.network for configuration details
+# See mesh.04-batman.network for configuration details
 [NetDev]
-Name=bat0
+Name={batdev}
 Description=BATMAN interface
 Kind=batadv
 
-# Use default settings. Uncomment to change
+# See man:systemd.netdev(5) § [BATMANADVANCED] SECTION OPTIONS
-# see man:systemd.netdev(5) § [BATMANADVANCED] SECTION OPTIONS
+[BatmanAdvanced]
-#[BatmanAdvanced]
+# This helps choose the best network when many nodes have a DHCP
+# server. See the B.A.T.M.A.N. documentation at
+# https://www.open-mesh.org/projects/batman-adv/wiki/Gateways
+GatewayMode={gateway_mode}

systemd-networkd/mesh.02-bridge.netdev

@@ -1,8 +1,8 @@
 # Create a bridge interface
 # The batman interface be will later linked to this bridge.
-# See 07-bridge.network to see how this bridge is configured
+# See mesh.07-bridge.network to see how this bridge is configured
 [NetDev]
-Name=bridge0
+Name={bridgedev}
 Description=Bridge
 Kind=bridge
 

systemd-networkd/mesh.03-wireless-ad-hoc.network

@@ -10,7 +10,7 @@ MTUBytes=1560
 
 [Network]
 Description=ad-hoc network connecting to other nodes
-BatmanAdvanced=bat0
+BatmanAdvanced={batdev}
 # This interface should not have any IP addresses assigned.
 # IP will be given later to the bridge
 DHCP=no

systemd-networkd/mesh.04-batman.network

@@ -1,11 +1,11 @@
 [Match]
-Name=bat0
+Name={batdev}
 
 [Network]
-Description=The BATMAN interface
+Description=Configuration for the BATMAN interface
-Bridge=bridge0
+Bridge={bridgedev}
 
-# like in 03-wireless-ad-hoc.network, this interface
+# like in mesh.03-wireless-ad-hoc.network, this interface
 # also shouldn't have IP address the address will
 # be assigned to the bridge
 DHCP=no

systemd-networkd/mesh.05-wireless-ap.network

@@ -8,10 +8,10 @@
 WLANInterfaceType=ap
 
 [Network]
-Description=Wireless AP
+Description=Configuration for Wireless AP
 
 # link the interface to the bridge
-Bridge=bridge0
+Bridge={bridgedev}
 
 # Like in the ad-hoc network and bat0, this interface
 # should not have any ip address assigned to it.

systemd-networkd/mesh.06-eth.network

@@ -1,8 +1,9 @@
 # This file bridges any ethernet device found
-# to the bridge made in 02-bridge.netdev
+# to the bridge made in mesh.02-bridge.netdev
 [Match]
 Name=en*
 Name=eth*
 
 [Network]
-Bridge=bridge0
+Description=Connect ethernet to the bridge
+Bridge={bridgedev}

systemd-networkd/mesh.07-bridge.network

@@ -3,13 +3,15 @@
 # communicate with others devices
 
 [Match]
-Name=bridge0
+Name={bridgedev}
 
 [Network]
-# use DHCP to assign an IP
+Description=bridge to link non-batman machines
+# Use DHCP to assign an IP
 DHCP=yes
 
-# if DHCP fails, assign a random address
+# If DHCP fails, assign a random address. This is probably the default,
+# but we are specifying it anyway.
 LinkLocalAddressing=yes
 
 # LLMNR and MulticastDNS are used for hostname discovery

systemd-networkd/tmp.01-eth.network

@@ -0,0 +1,10 @@
+# This is used to check if any ethernet or USB ethernet ports
+# is connected to a router or some other device with a DHCP server.
+# After checking, this file is no longer needed.
+[Match]
+Name=eth*
+Name=en*
+
+[Network]
+Description=Check for ethernet connection
+DHCP=yes