This provides a simple virtual network device to transmit and receive ethernet packets, encoded as QR codes, using carrier pigeons. With some additional hardware and network configuration, it can be used to implement RFC 1149 on a Linux system. We used a BeagleBone Green along with a thermal receipt printer from Adafruit and a Linux-compatible webcam. It is also possible to use ordinary USB flash drives, so the project can run happily on an ordinary Linux system.
It was created for CMPT 433 at Simon Fraser University. If you can find your way around my sleep-deprived code and coax this project into working, you are amazing.
The pigeond program opens a "pigeon0" network device using the tun/tap interface. It sends and receives data over this device using the IP Over Avian Carrier Protocol. Bridging to a physical network device happens externally.
To build on Ubuntu, you will need to install some dependencies:
sudo apt install libasound2-dev libqrencode-dev libv4l-dev libzbar-dev
Note that equivalent armhf libraries and header files (to cross-compile for BeagleBone) are included for your convenience.
To build for all architectures:
make
The output will be located in ./our/default/ and ./out/armhf/. Use "build.default" or "build.armhf" for all to build for a specific architecture.
To build for armhf and copy the resulting binary to ${HOME}/Public:
make export
To remove build output:
make clean
To create a Debian package for the current architecture, which can be installed using dpkg -i:
dpkg-buildpackage -b -uc -us
This is the recommended way to install pigeond, along with its system configuration, so it can be used as a system service.
Currently we work with a hard-coded persistent network device. For testing, you can create and configure this device using the ip command:
sudo ip tuntap add pigeon0 mode tap
sudo ip link set pigeon0 up
sudo ip addr add 10.0.0.1/24 dev pigeon0
Finally, run pigeond and it will connect to the pigeon0 device.
Please install the Debian package, which includes a systemd service file for pigeond. Enable the pigeond service to run automatically:
sudo systemctl enable pigeond
Unfortunately, the rest of the configuration is manual...
First, we need to enable the BB-BONE-AUDI-02 and BB-I2CI capes at startup. Edit /etc/default/capemgr and add this line:
CAPE=BB-BONE-AUDI-02,BB-I2C1,BB-UARTS
If you need to use the file transfer mode, we should set an environment variable for pigeond with a location where a device will reliably appear. Edit /etc/default/pigeond with something like this:
PIGEOND_FILES_TX=/media/PGN_Ada
PIGEOND_FILES_RX=/media/PGN_Grace
Note: TX and RX must point to the base directory of two separate USB storage devices.
To enable the printer module, include PIGEOND_PRINTER_TX=yes. To enable the camera module, include PIGEOND_CAMERA_RX=yes.
For our bridge interface to work, we need to stop eth0 from being assigned an IP address. To do this, disable connman's ownership of the eth0 interface. In /etc/connman/main.conf, change this line:
NetworkInterfaceBlacklist=usb0,SoftAp0
... to include eth0, pigeon0 and br0:
NetworkInterfaceBlacklist=usb0,SoftAp0,eth0,pigeon0,br0
Now we need to configure a persistent pigeon0 device and a network bridge between eth0 and pigeon0. In /etc/network/interfaces, add these lines:
iface eth0 inet manual
auto pigeon0
iface pigeon0 inet manual
pre-up ip tuntap add pigeon0 mode tap
pre-up ip link set pigeon0 multicast off
post-down ip link del dev pigeon0
auto br0
iface br0 inet manual
bridge_ports eth0 pigeon0
post-up ip link set dev pigeon0 up
post-up ip link set dev eth0 up
post-down ip link set dev pigeon0 down
post-down ip link set dev eth0 down
Reboot the device and it should behave like a layer 2 hub (with some quirks). You can connect a device to the ethernet port, and any messages going over that port will be sent to our carrier pigeon interface. Any device we connect will need to configure its own network settings appropriately so it can communicate with whatever device is on the other end. For example, each device should have a static IP address like 192.168.10.2, and a netmask like 255.255.255.0. You should set an MTU of 170.
Note that our device will drop IPv6 frames as well as IP broadcast frames. These were too noisy for our carrier pigeons to manage. Some applications may behave unexpectedly as a result.
You can view a log for pigeond using journalctl:
sudo journalctl -u pigeond -f
It is also useful to use tshark to watch the pigeon0 device:
sudo tshark -i pigeon0
By default, BeagleBone's operating system doesn't have a way of mounting storage devices when they are inserted. If you are already running a system that automatically mounts disks in a reliable way, you don't need to do this.
Let's install udevil for its devmon tool. (This sucks, but trust me, the other options here are worse).
sudo apt install udevil
Now, create a service file for devmon at /etc/systemd/system/devmon.service:
[Unit]
Description=Device monitoring daemon
[Service]
ExecStart=/usr/bin/devmon
Restart=on-failure
[Install]
WantedBy=multi-user.target
Now start and enable it...
sudo systemctl start devmon
sudo systemctl enable devmon
- Adam Shambrook ([email protected])
- Dylan McCall ([email protected])
- Sunny Singh ([email protected])