[pulseaudio-tickets] [Bug 40869] New: module-tunnel sinks disappear on multihomed machine when one of the interfaces is disconnected

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=40869

           Summary: module-tunnel sinks disappear on multihomed machine
                    when one of the interfaces is disconnected
           Product: PulseAudio
           Version: unspecified
          Platform: Other
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: modules
        AssignedTo: pulseaudio-bugs at lists.freedesktop.org
        ReportedBy: rudd-o at rudd-o.com
         QAContact: pulseaudio-bugs at lists.freedesktop.org
                CC: lennart at poettering.net


At home, I have a multihomed machine (same IP on both interfaces) that has two
network interfaces: LAN, WLAN.  These two network interfaces are configured to
have the same IP address, but different routing priorities (higher for the
LAN), and NetworkManager enables/disables them based on the presence or absence
of network connection.

(I am oversimplifying a bit here -- there is a VPN network interface that is
only used if I am on the go, and that's also multihomed, and it works
flawlessly too -- it is exactly as if I was home, barring latency -- but this
bug is present regardless of that).

This is highly advantageous because it lets me unplug my network cable when I
need mobility, then re-plug it again when I need high throughput, and programs
using the network connection continue to work normally without the need to
"reconnect" (NFS mounts, Skype, Web sites, et cetera).

Even PulseAudio works well in that scenario -- plug the network cable and the
traffic begins to be automatically transmitted by the LAN interface.

There's one problem, though:

~@karen.dragonfear α:
avahi-browse -a | grep pulse
+  wlan0 IPv4 pulse at paola.dragonfear: Internal Audio        PulseAudio Sound
Sink local
+  wlan0 IPv4 pulse at paola.dragonfear                        PulseAudio Sound
Server local
+  eth0 IPv4 pulse at paola.dragonfear: Internal Audio        PulseAudio Sound
Sink local
+  eth0 IPv4 pulse at paola.dragonfear                        PulseAudio Sound
Server local

When the multihomed machine is running fine, my network PulseAudio server
connected to my stereo appears twice in Avahi, and once in paman/pavucontrol. 
This would not be much of a problem, since PulseAudio works fine.

Except, when I unplug one of the cables, of course, the server and sink
attached to the specific network interface disappears.  Which leaves the other
one (WLAN) STILL available, but for some reason PulseAudio on my multihomed
machine thinks it's "gone" and, of course, the sinks just disappear even though
avahi-browse clearly shows them.

IOW:

    connect WLAN: sink becomes available in local server
    connect LAN: everything continues as normal
    disconnect LAN: sink disappears from local paman/pavucontrol
    connect LAN: sink no longer appears anymore, have to restart server to
force another MDNS announcement

To "fix this", I must restart the server either locally or in my stereo
computer.

I would think the proper fix is to double-check with Avahi to see whether the
server and sink with the same name are still available before deciding "oops,
it's gone" and making it unavailable.  Another fix would be to verify that the
TCP connection to the server is still vaild before deciding "oops, it's gone". 
Or, to keep a counter per server keyed to the server name, so that the sequence
would be 0 1 2 1 0, and only when it reaches 0, it is made unavailable.

Version: pulseaudio-0.9.22-5.fc15.x86_64

-- 
Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
You are the assignee for the bug.