Multicast / igmpproxy broken in 20.7 (FreeBSD 12)

[uglymotha]

I discovered a pretty serious issue with multicast in version 20.7 / FreeBSD 12. Multicast groups are joined, but never left. This causes streams to keep running indefinitely and can quickly saturate upstream links.

I am currently in the process of rewriting / overhauling the igmpproxy source code and discovered this issue after upgrading my opnsense installation from 20.1 to 20.7. After testing using stock installatins, I established the issue is present since FreeBSD 12, up to the most recent stable p8 release.

I have opened up a bug report with FreeBSD:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=248512

For now I would advice anybody using multicast routing / igmpproxy to stay away from 20.7.

[uglymotha]

Issue was fixed a few weeks ago, and no longer exists in FreeBSD latest snapshot kernel.
https://svnweb.freebsd.org/base?view=revision&revision=362472

The hardened BSD kernel in use by opnsense however still suffers from this rather nasty bug, rendering multicast pretty much unusable. I took the liberty of opening a PR for their stable branch, but don't know whether they'll accept it.

Is there any documentation for compiling a custom kernel to use with opnsense? I would rather go that route than downgrading to 20.1. Hardned BSD dev branch is up to date with FreeBSD, last merge there was a few days ago.

[franco]

FreeBSD 12.1 suffers still and may never receive a fix. Honestly, I doubt their release engineering approach with regards to a reliable release as it seems to mean reliable in "features as well as bugs".

I followed the discussion, added:

https://github.com/opnsense/src/commit/d6dc01f471b4

You can try the kernel to help get this into 20.7.1:

# opnsense-update -kr 20.7-mcast
# opnsense-shell reboot


Cheers,
Franco

[staticznld]

Thanks Franco!

It looks like the same problem i have.

https://forum.opnsense.org/index.php?topic=18347.0

Going to try the new kernel tonight or tomorrow.

[franco]

Thanks for the link. I was looking for the topic briefly to post a reference but happy you found this directly.


Cheers,
Franco

[uglymotha]

Unfortunately the issue persists  with the supplied test kernel. It must have been a different bug and commit that fixes this. Most likely:
https://github.com/freebsd/freebsd/commit/63bc20993b4f570ff1a7c45b5dead0109768d494#diff-c9065ed6e74837c7cb1ded9eb39e7fb9

[staticznld]

Installed kernel but no succes.

Multicast streams keeps stacking up.
Also after 4 minutes the tvstream looses connectivity. All multicast stream are gone.

Also a lot of error in the log of igmpproxy

igmpproxy[77319]: MRT_DEL_MFC; Errno(49): Can't assign requested address

[franco]

Patchfest... yay, new kernel coming soon. Hold tight.


Cheers,
Franco

[franco]

# opnsense-update -kr 20.7-re-mcast
# opnsense-shell reboot


Cheers,
Franco

[staticznld]

Thanks for the new test kernel!

Tried the the new kernel but still no succes.
Errors are gone in the system log, when stopping igmp proxy multicast streams stop comming in.
But when zapping through TV channels multicast traffic is still stacking up.

Edit:

Still seeing error mesages in the log
igmpproxy[6669]: MRT_DEL_MFC; Errno(49): Can't assign requested addres

[franco]

I'm open for suggestions. But just for documentation purposes... I did not expect this particular adventure down the rabbit hole.


Cheers,
Franco

[franco]

Last try for the day:

https://github.com/opnsense/src/commit/6a106324130

Kernel to install:

# opnsense-update -kr 20.7-re-mcast2
# opnsense-shell reboot

(Will be available in a few minutes)


Cheers,
Franco

[staticznld]

Woohoo!!

It looks like the leave requests are leaving with this kernel!
Still some testing to do, but the first results are fine!
Everything looks like 20.1 now!

Thanks for the awsome support gonna make a donation today!

[heresjody]

Franco I can confirm the mcast2 kernel solves the leaving multicast problems. Thanks! Do I understand correctly this fix will be tweaked into the kernel for the upcoming 20.7.1 release?

[franco]

Thanks all! Yes, we will include this in 20.7.1. ETA is Thursday this week.


Cheers,
Franco