[Sugar-devel] Telepathy Salut on Sugar 0.102 on Fedora 20 almost works

[Gonzalo Odiard]

Thanks James for research and reporting!

On Tue, Sep 16, 2014 at 4:53 AM, James Cameron <quozl at laptop.org> wrote:

> Summary: partially solved with new kernel.
>
> The Chat activity was run with debug logging in Terminal:
>
>         % SUGAR_LOGGER_LEVEL=debug sugar-launch org.laptop.Chat
>
> At the time the activity was shared, the log showed:
>
> 1410842095.436535 DEBUG sugar3.presence.activity: <_ShareCommand object at
> 0x527dc8 (sugar3+presence+activity+_ShareCommand at 0x4f7c20)>: Join
> finished DBusException(dbus.String(u'Failed to connect to multicast
> group'),)
>
> Telepathy Salut was failing to setup the multicast group, because it
> was calling setsockopt with SO_REUSEPORT, because Fedora 20 header
> files define SO_REUSEPORT, but the OLPC kernel did not.
>
> (It is bad that the failure was not reported to the user or to the
> logs unless debug logging was turned on.  If someone cares, they can
> raise a bug.)
>
> Adding SO_REUSEPORT support to the kernel [2] solved for Salut over
> networks where DHCP is available; such as wired or wireless access
> points.  The new kernel is in the dropbox [3].  The previous change to
> avahi-daemon configuration is removed [4].
>
> A different problem occurs with Salut over link local addresses; IBSS
> ad-hoc wireless.  The buddy icons are missing.
>
>         # avahi-browse -t _presence._tcp # shows no output
>
> References:
>
> 1.
>
> http://code.metager.de/source/xref/freedesktop/telepathy/salut/lib/gibber/gibber-multicast-transport.c
>
> 2.
> http://dev.laptop.org/git/olpc-kernel/log/?h=arm-3.5
>
> 3.
> http://rpmdropbox.laptop.org/f20-xo4/
> kernel-3.5.7_xo4-20140916.0607.olpc.5196e01.armv7hl.rpm
>
> 4.
>
> http://dev.laptop.org/git/projects/olpc-os-builder/commit/?id=f34ddb8b83ca6b9cb657e115df117ffa3704eea5
>
>
> On Thu, Sep 11, 2014 at 06:24:20PM +1000, James Cameron wrote:
> > G'day,
> >
> > Activities shared by Fedora 20 systems do not appear in Network
> > Neighbourhood on Fedora 18 or Fedora 20 systems.  Buddies appear.
> > Activities shared by Fedora 18 Sugar 0.98 systems appear.
> >
> > So this is a failure to announce sharing of activities on Sugar 0.102
> > on Fedora 20.
> >
> > tcpdump shows mDNS packets for every operation except when an activity
> > is shared on Fedora 20.
> >
> > avahi-browse output is consistent with Network Neighbourhood.
> >
> >       avahi-browse -t _presence._tcp # for buddies
> >       avahi-browse -t _clique._udp # for activities
> >
> > (avahi-daemon needed tweaking to compensate for lack of SO_REUSEPORT
> > support in 3.5 kernel; change /etc/avahi/avahi-daemon.conf to set
> > disallow-other-stacks=yes)
> >
> > I have tried http://wiki.sugarlabs.org/go/BugSquad/Telepathy_Debugging
> > but there is no interesting output corresponding to the event.
> >
> > I have used strace and seen possible D-Bus activity relating to the
> > event.  sendmsg(11, {msg_name(0)=NULL,
> msg_iov(2)=[{"l\1\0\1<\0\0\0/\0\0\0\252\0\0\0\1\1o\0?\0\0\0/org/fre"...,
> 192}, {"+\0\0\0org.freedesktop.Telepathy.Ch"..., 60}], msg_controllen=0,
> msg_flags=0}, MSG_NOSIGNAL) = 252
> >
> > I welcome any suggestions for further diagnosing this problem.
> >
> > --
> > James Cameron
> > http://quozl.linux.org.au/
>
> --
> James Cameron
> http://quozl.linux.org.au/
> _______________________________________________
> Devel mailing list
> Devel at lists.laptop.org
> http://lists.laptop.org/listinfo/devel
>



-- 
Gonzalo Odiard

SugarLabs - Software for children learning
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