Subject: bug#52520: closed (Re: bug#52520: Multicast is off by default)

From: [email-masked] (GNU bug Tracking System)
Date: Tue, 21 Dec 2021 19:41:02 +0000

Your bug report

#52520: Multicast is off by default

which was filed against the guix package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to [email-masked].

-- 
52520: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=52520
GNU Bug Tracking System
Contact [email-masked] with problems

Subject: Re: bug#52520: Multicast is off by default
From: Mathieu Othacehe <[email-masked]>
To: Ludovic Courtès <[email-masked]>
Cc: Julien Lepiller <[email-masked]>, [email-masked]
Date: Tue, 21 Dec 2021 20:40:29 +0100
List-Id: <debbugs-submit.debbugs.gnu.org>

Hey,

> BTW, for the purposes of fixing the bug you initially reported, I
> suggest simply adding #:multicast-on #t as you initially proposed.
> We discuss the proper API separately.

Done with: d2f9578a9f1249dfecb0a6b4cd06fd9641fcd1a9.

Thanks,

Mathieu

Subject: Multicast is off by default
From: Mathieu Othacehe <[email-masked]>
To: [email-masked]
Date: Wed, 15 Dec 2021 20:36:06 +0100
List-Id: <debbugs-submit.debbugs.gnu.org>

Hello,

Since the guile-netlink switch the static IP interfaces no longer have
multicast support. This can be confirmed this way:

--8<---------------cut here---------------start------------->8---
4: eno4: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether b0:26:28:b7:9d:09 brd ff:ff:ff:ff:ff:ff
5: eno2: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether b0:26:28:b7:9d:0b brd ff:ff:ff:ff:ff:ff
    inet 141.80.181.40/24 brd 141.80.181.255 scope global eno2
       valid_lft forever preferred_lft forever
    inet6 fe80::b226:28ff:feb7:9d0b/64 scope link 
       valid_lft forever preferred_lft forever
--8<---------------cut here---------------end--------------->8---

eno2 that is managed by the static-networking service is lacking
multicast support, while eno4 that is not managed by this service has
multicast support.

This can be adjusted by running:

--8<---------------cut here---------------start------------->8---
ip link set multicast on eno1
--8<---------------cut here---------------end--------------->8---

which immediately fixes Avahi discovery that depends on it.

I think that we could maybe apply the following patch, even though I
didn't test it.

--8<---------------cut here---------------start------------->8---
diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 5f93483dda..af3fe015b9 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -2546,6 +2546,7 @@ (define network-set-up/linux
                                                 #$(network-address-ipv6? address))
                                       ;; FIXME: loopback?
                                       (link-set #$(network-address-device address)
+                                                #:multicast-on #t
                                                 #:up #t)))
                                 addresses)
--8<---------------cut here---------------end--------------->8---

Thanks,

Mathieu