/dev/fanout

Kernel-based publish-subscribe system

WHAT:

• simple, efficient, broadcast IPC, or alternatively
• simple, efficient, publish-subscribe IPC
• kernel module implementing a character device

WHY:

• Efficient: Only N writes for N subscribers compared to 2*N writes for a sockets based system
• Simple: Kernel based, no need for a new process or daemon
• Simple: Use mknod to create a channel or topic as a device node
• Simple: API is just open()/read()/write()/close()
• Simple: Works with select() for event driven programming
• Simple: Works with ALL programming languages, even Bash
• Simple: No dependencies and no libraries to install
• Simple: Builds on all Linux systems
• Secure: Access rights tied to filesystem permissions on device node

INSTALLATION:

// comment out #define DEV_MKNOD if on Ubuntu 20.04.
sudo apt-get install linux-headers-`uname -r`
git clone --depth=1 https://github.com/bob-linuxtoys/fanout
cd fanout
make
sudo make install

TEST:

sudo modprobe fanout   # load the kernel module, create 8 nodes
# rename one of the nodes for our use of it
# (or create /dev nodes manually if Ubuntu 20.04)
sudo mv /dev/fanout7 /dev/fanouttest
# Add three subscribers to the topic on /dev/fanouttest
cat /dev/fanouttest &
cat /dev/fanouttest &
cat /dev/fanouttest &
# Publish a messagte to fanouttest topic
echo Hello, World > /dev/fanouttest

NOTES:

See http://linustoys.org for an article on fanout. See Linux Journal of August, 2010 for another article See also http://github.org/bob-linuxtoys/proxy

COPYRIGHT

Copyright 2010-2021, Bob Smith, Frederic Roussel

LICENSE:

At your discretion, you may consider this software covered by either the GNU Public License, Version 2, or the BSD 3-Clause license. http://opensource.org/licenses/GPL-2.0 http://opensource.org/licenses/BSD-3-Clause