linux-user missing cmsg IP_PKTINFO support ("Unsupported ancillary data: 0/8")

[Tobias Quintern]

Hello,

I have the following issue when launching the Teamspeak Server x86 binary on an arm host.

Host:
 Linux 4.6.2 (vanilla)
 Ubuntu 14.04.5 LTS
 HW: Cubietruck board, armv7l

Used SW: Release archive qemu-2.7.0.tar.bz2 and git commit 1dc33ed90bf1fe1c2014dffa0d9e863c520d953a
Configure options:
  ../configure --target-list=i386-linux-user
I attached the output of the configure script as configure.log

Testcase:

1. Download and extract TeamSpeak 3 Server 3.0.13.3 (x86)
  Souce: http://dl.4players.de/ts/releases/3.0.13.3/teamspeak3-server_linux_x86-3.0.13.3.tar.bz2

2. Modifiy ts3server_minimal_runscript.sh for ease of use
  - ./ts3server $@
  + /usr/local/bin/qemu-i386 ./ts3server $@

3. Execute ./ts3server_minimal_runscript.sh

Wait for 6 Minutes until teamspeak server started. QEMU saturates the cpu while Teamspeak is precomputing a puzzle. (Whatever that means)

After that Teamspeak settles with the following output:
  2016-09-03 10:50:59.555582|INFO |Query | |listening on 0.0.0.0:10011, :::10011

The Qemu process is now idling with ~2% cpu load. This is actually the first time for me that QEMU is able to successfully launch the Teamspeak server. Kudos!

4. Connect client 1

TS Clients can connect, but the following line is printed pretty often:
  Unsupported ancillary data: 0/8

The line seems to come from qemu (linux-user/syscall.c)

5. Connect client 2
When a second client is connected the audio transmission is successful for a few seconds, but the server drops the connection after that and refuses to take new connections.

Please let me know, if you need more information. I'll gladly provide strace or valgrind logs.

Best regards,
Tobias

[Tobias Quintern (tobias-quintern)]

Kindly note that the issue does not occur with TeamSpeak 3 Server 3.0.12.4 (x86)

[Peter Maydell (pmaydell)]

cmsg level/type 0/8 is SOL_IP / IP_PKTINFO. QEMU's handling of sendmsg/recvmsg control messages needs specific support for each type of message, and we currently do not have any support for most of them.

NB: given the description of the way client 1 at least is successful, the guest program may be successfully coping with the missing support, in which case the other failures would be somewhere else. It would be worth retrying with a recent version of QEMU if you still care about this guest program.

[Gabriele (gabboxl)]

Hi, I'm facing the same issue when someone connects to the server. I tried with the 4.2 version of qemu today.

[Gabriele (gabboxl)]

Oh, I forgot to mention that with multiple clients the TS server works well, it only keeps printing "Unsupported ancillary data: 0/8" in the console.

[Thomas Huth (th-huth)]

This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/127