“Elegance is not a dispensable luxury” — Edsger Wybe Dijkstra

Inetd Support in Finit v1.12

A steady flow of features, and releases, is key to keeping any project alive. Recently I ticked off another item in the Finit TODO list …

Finit v1.12 now comes with a built-in inetd! You no longer need an external inetd daemon to launch services on demand.

The good news doesn’t stop there, this little inetd actually supports a poor man’s tcpwrappers!

inetd ssh/tcp          nowait [2345] /sbin/dropbear -i -R -F
inetd ssh@eth0:222/tcp nowait [2345] /sbin/dropbear -i -R -F

With these two lines in your /etc/finit.conf you tell finit to launch the Dropbear SSH server on demand on port 22 (default ssh/tcp port in /etc/services) on all interfaces except on eth0, which in your case is the Internet (WAN) interface, here you want SSH to run on port 222. Actually, you don’t want port 22 open at all on eth0 … so finit takes care of this for you! Seriously, it just works, no need for messing about with that nasty old iptables anymore!

The original UNIX inetd super server supported many protocols internally, some of which may seem a bit odd today, and some have been superseded by more modern protocols.

Finit currently only supports one internal/built-in standard service, time. It is built as a plugin to serve as an example of how you can extend Finit yourself. The time service can be called either as UDP or TCP. To prevent security issues, the time protocol is disabled by default. To enable it you need two things:

  1. The plugin (built by default)
  2. An inetd time ... line in /etc/finit.conf

Assuming you’ve installed the default set of plugins, the following two lines can be added:

inetd time/udp   wait [2345] internal
inetd time/tcp nowait [2345] internal

This can be very useful for testing the inetd capabilities, your network connection, or simply to get the time to a client where NTP for some reason does not work, or is blocked. For instance, you could have a GPS setup on your server and distribute time to clients with the time protocol.

To use it you need an rdate client. Users of rdate in BusyBox may need to be reminded that it only supports TCP.

$ rdate -pu
Sat Mar  7 08:48:58 CET 2015

For more info on Finit and its features, see the README.

Enjoy! ツ

Finit v1.11 Released!

Update 2015-03-09: This release has unfortunately been yanked due to serious regressions in launching background processes. It has been replaced by v1.12

Rant: All the C Compiler Warnings …

“Enable all the warnings!”

This is one of the truths you learn when you start working with C. Most of the time adding CPPFLAGS="-W -Wall -Werror" is all you need to find all the nasty bugs. And if that’s not enough, there are tons of tools for static code analysis, like scan-build in Clang, and Coverity Scan, to help you find all the bugs!

However, these pesky warnings (some of which cannot even be disabled!) are sometimes more of a nuisance than help. Sometimes you know that some parameters to a function will remain unused – it’s a callback, and you don’t need all the data given to you. So you start adding all kinds of voodoo, like __attribite__ ((unused)) … seriously?

Recent Open Source Work

I’m a coder, not a writer. Here’s what I’ve been working on during the winter holidays:

  • A new feature release of Finit is coming shortly, which will use libuEv and feature inetd support built-in!
  • Another minor release of my own take on event loops, libuEv v1.0.3. This time with a heavy focus on documentation and Q&A, extensive validation testing have been done on this release.
  • Released another minor release of mrouted, v3.9.7, which despite its age, and all other obvious limitations of DVMRP, is still one of the best options for dynamic multicast routing available today.
  • Major new release of pimd, v2.2.0, which is likely the last release ever of the old pimd, unless someone starts paying me to work on it.

    … or more people step up to help. Both the Xorp PIM-SM and the upcoming Quagga PIM-SSM implementations are in better shape. The only thing old pimd has got going for it is the license. It’s 3-clause BSD, so very liberal.

If you’re interested in pitching in, on any of my projects, just send me an email or connect with me on GitHub!

Blog Restoration Project

I’ve had this long-standing issue with backups. It’s deadly boring to set up and maintain, so I don’t do any. Until today!

Today I moved the sources for my Octopress blag to GitHub, which also prompted me to set up a mirror on GitHub Pages. As usual, reading up on the subject and muster enough motivation took me about three months, whereas the actual work took about 4h.

Pimd v2.2.0 – the Last Release of Pimd?

On one of the last days of 2014 I release pimd v2.2.0, which is an awesome release with a lot of new features and bug fixes!

However, it could very well be the last release I do. Even though its one of my most popular projects on GitHub I have not had enough time to dedicate to it over the years. I will continue to do fixes and merge pull requests until someone else steps up to take over. There is also the distinct possibility that the Xorp PIM-SM or the new Quagga PIM-SSM implementations will (finally) make good old pimd completely redundant.

At work we will likely start using the Quagga PIM rather than pimd in WeOS.

For now though, enjoy pimd v2.2.0. It’s been tested in both my Qemu based virtual testbed and a few setups using Linux’ netns feature in CORE – awesome little proggy! :-)

HowTo Add Multicast Routing Support to the FreeBSD Kernel

This is a very short blog post, mostly intended as a reminder to myself. Assumes the src.txz was installed previously. Here goes:

cd /usr/src
cd sys/amd64/conf
echo 'options   MROUTING         # Multicast routing' >> MULTICAST
cd -

That’s it. Remember to make sure your Qemu VM has enough RAM or it will probably page fault on you. I use 1,0 GB RAM.

GnuTLS Support in Inadyn and Fixes to Uftpd

Quite a few changes lately. I finally got around to adding support for GnuTLS to Inadyn, hopefully this will get into Debian … unless the Jessie freeze prevents that.

Also, thanks to a friend of mine trying out uftpd recently I discovered that libuev has been missing from the tarball since the release of the TFTP support. Fixed.

Another great piece of news is that Coverity accepted uftpd as an Open Source project, I’ve been hard at work fixing nasty bugs uncovered by the Coverity Scan. Great stuff! :)