gst-plugins-bad: avtp: error on gst_avtp_src_start:<avtpsrc0> Failed to open socket: Operation not permitted

Thu Jul 16 20:19:02 UTC 2020

On Thu, 2020-07-16 at 15:33 -0400, John Rama wrote:
> Hello Desounza,
> 
> Thanks for your input.
> 
> > > ------------------------------------------------------------------------------------------------------------
> > > $gst-launch-1.0  avtpsrc ifname=enp8s0  ! avtpcvfdepay ! avdec_h264 ! fakevideosink
> > > 
> > > (gst-launch-1.0:8639): GStreamer-WARNING **: Failed to load plugin '/home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-plugins-bad/ext/avtp/libgstavtp.so': /home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-plugins-bad/ext/avtp/../../../gstreamer/libs/gst/base/libgstbase-1.0.so.0: undefined symbol: gst_message_new_instant_rate_request
> > > 
> > > (gst-launch-1.0:8639): GStreamer-WARNING **: Failed to load plugin '/home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-plugins-bad/ext/avtp/libgstavtp.so': /home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-plugins-bad/ext/avtp/../../../gstreamer/libs/gst/base/libgstbase-1.0.so.0: undefined symbol: gst_message_new_instant_rate_request
> > > 
> > > (gst-launch-1.0:8639): GStreamer-WARNING **: Failed to load plugin '/home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-libav/ext/libav/libgstlibav.so':/home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-libav/ext/libav/../../../gstreamer/libs/gst/base/libgstbase-1.0.so.0: undefined symbol: gst_message_new_instant_rate_request
> > > 
> > > (gst-launch-1.0:8639): GStreamer-WARNING **: Failed to load plugin '/home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-plugins-bad/gst/debugutils/libgstdebugutilsbad.so': /home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gst-plugins-bad/gst/debugutils/../../../gstreamer/libs/gst/base/libgstbase-1.0.so.0: undefined symbol: gst_message_new_instant_rate_request
> > 
> > This looks like something is messed up on your environment - please
> > ensure that all subprojects are updated, try building from a clean
> > environment, etc.
> > 
> 
> I confirmed before setcap, following pipleline works.
> $gst-launch-1.0 videotestsrc num-buffers=1 ! fakevideosink
> 
> Then if I do setcap, the same pipeline does not work.
> $sudo setcap cap_net_raw+ep /home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gstreamer/tools/gst-launch-1.0
> $gst-launch-1.0 videotestsrc num-buffers=1 ! fakevideosink
> ...
> gst-launch-1.0: symbol lookup error: gst-launch-1.0: undefined symbol: gst_printerr
> 
> $gst-launch-1.0 videotestsrc num-buffers=1 ! fakevideosink
> 
> Then if I do remove the capability, it work again.
> $sudo setcap -r /home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gstreamer/tools/gst-launch-1.0
> $gst-launch-1.0 videotestsrc num-buffers=1 ! fakevideosink
> 
> So, setcap definitely affect this problem.
> 
> 
> After investigating more, it turned out this is because of linker behavior.
> 
> https://bugs.java.com/bugdatabase/view_bug.do?bug_id=7157699
> 
> > When one is raising the privileges of an executable, the runtime loader (rtld),
> > better know as ld.so will not link with libraries in untrusted paths.
> > This is the way the ld.so(1) has been designed. If one needs to run such an
> > executable, then you have to add that path to the trusted paths of ld.so
> 
> After adding the path of libgstreamer-1.0.so.0 to linker, it works.
> $cat /etc/ld.so.conf.d/gst-test.conf 
> /home/makoto/Work/src/gstreamer/gst-build-master/build/subprojects/gstreamer/gst/
> $sudo ldconfig 

Yeah, ld is picky with capabilities and non-default paths, sorry not
having noticed that...

> 
> (In my environment, I need to do this, even LD_LIBRARY_PATH is already set to the
> correct path to use gstreamer plugins by "ninja -C build devenv".)
> 
> ======================================================================
> 
> So, after fixing this problem, the pipeline has no error. 
> But I have another problem....
> But, fakesink does not receive no data...
> 
> $gst-launch-1.0 avtpsrc ifname=enp8s0 '!' avtpcvfdepay '!' avdec_h264 '!' videoconvert '!' fakesink dump=true
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> Pipeline is PREROLLED ...
> Setting pipeline to PLAYING ...
> New clock: GstSystemClock
> ...
> 
> Followings returns some data..
> $gst-launch-1.0 avtpsrc ifname=enp8s0 '! fakesink dump=true
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> Pipeline is PREROLLED ...
> Setting pipeline to PLAYING ...
> New clock: GstSystemClock
> 00000000 (0x7f3338003c90): 03 88 83 00 01 23 45 67 89 ab cd ef 00 00 00 00  .....#Eg........
> 00000010 (0x7f3338003ca0): 02 01 00 00 01 7b 20 00 16 17 89 67 5c 81 9a 6e  .....{ ....g\..n
> 00000020 (0x7f3338003cb0): 93 c2 1e 4c a6 04 ff 01 89 c8 c3 dd 80 10 11 8d  ...L............
> 
> But Followings does not return no data...
> $gst-launch-1.0 avtpsrc ifname=enp8s0 '!' avtpcvfdepay '!' fakesink dump=true
> Setting pipeline to PAUSED ...
> Pipeline is live and does not need PREROLL ...
> Pipeline is PREROLLED ...
> Setting pipeline to PLAYING ...
> New clock: GstSystemClock
> 
> Can you think of any reason why ?

AVTP streams have a streamid - have you tried using:

... ! avtpcvfdepay streamid=<stream-id> ! ...

Also note that you can get debug information from the avtp plugin with:

GST_DEBUG=avtp*:<debug-level> gst-launch-1.0

So you can check what the plugin is doing.

> 
> (I have already confirmed that my PC enp8s0 is receiving the CVF stream with VLAN ID 2 (PCP=3).
>  Do we need to do something to receive the stream with VLAN ?)
> 
> ======================================================================
> 
> Another question is 
> 
> This document describes I need to put -k ptp option to gst-launch-1.0.
> https://gstreamer.freedesktop.org/documentation/avtp/index.html?gi-language=c

Ouch, that's "hypothetical" =D
In the end, a way to set the pipeline clock when testing with
gst-launch is to use debugutilsbad "clockselect" element:

gst-launch-1.0 clockselect. \( clock-id=<clockid> <your pipieline here> \)

You can use "gst-inspect-1.0 clockselect" for more information on that element.

I'll try to update that documentation. Thank you for the heads up.

> 
> But gst-launch-1.0 does not recognize "-k" option.
> $ gst-launch-1.0 -k ptp avtpsrc ifname=enp8s0 '!' avtpcvfdepay '!' fakesink dump=true
> Error initializing: Unknown option -k
> 
> $gst-launch-1.0 --version
> gst-launch-1.0 version 1.17.2
> GStreamer 1.17.2 (GIT)
> 
> Thanks for your help !!
> 
> John
> 
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