RadioTap Archive on lore.kernel.org
 help / color / Atom feed
From: Marcel Holtmann <marcel-kz+m5ild9QBg9hUCZPvPmw@public.gmane.org>
To: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
Cc: "Vadim Yanitskiy"
	<axilirator-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"Harald Welte" <laforge-TgoAw6mPHtdg9hUCZPvPmw@public.gmane.org>,
	"OpenBSC Mailing List"
	<openbsc-qjLDD68F18N4m7O/Vxda39i2O/JbrIOy@public.gmane.org>,
	"Sean Tranchetti"
	<stranche-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	radiotap-S783fYmB3Ccdnm+yROfE0A@public.gmane.org,
	"Dan Williams" <dcbw-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	netdev <netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"open list:NFC SUBSYSTEM"
	<linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"Aleksander Morgado"
	<aleksander-Dvg4H30XQSRVIjRurl1/8g@public.gmane.org>,
	"Subash Abhinov Kasiviswanathan"
	<subashab-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	"Bjørn Mork" <bjorn-yOkvZcmFvRU@public.gmane.org>
Subject: Re: gsmtap design/extensions?
Date: Wed, 10 Apr 2019 09:57:06 +0200
Message-ID: <6F1998DC-EFD2-4145-BD81-A80F9DC7ED2D__286.812269926884$1554887780$gmane$org@holtmann.org> (raw)
In-Reply-To: <46474c61d7748042cc0a1f23773186786020638e.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>

Hi Johannes,

>> FYI, there already was a discussion about GSMTAPv3:
>> 
>> https://www.youtube.com/watch?v=vum9jzavZi0&list=PL07C78AF831FFE8F9&index=10
>> 
>> but unfortunately, nobody has invested time into this (yet?).
> 
> 2012! But, umm, I don't really have time for a whole video right now -
> anyone have the slides? :-)
> 
> But yeah, the first slides look sensible :-)
> 
>>> 1) Why the design with encapsulating it in UDP?
>> 
>> This gives us a possibility to "demux" multiple GSMTAP streams on the
>> receiving side, e.g. if you are running multiple processes.
> 
> Not sure I get this, but I also don't really care all that much. It's
> just a pretty strange design if the kernel were to output this, I'm not
> even sure how I'd do that properly. I don't want to be generating UDP
> packets there...
> 
> Perhaps we can define something (GSMTAPv3) to not really care how it's
> encapsulated, and for 'native' packet captures like what I want on Linux
> when integrated with the driver, actually use an ARPHDR_GSMTAP, and
> encapsulate in UDP when you create it in an application and want to send
> it elsewhere, rather than just writing it to a pcap file?

before you go all out and define this, it would suggest to understand what meta-data for the connection contexts you actually need as well. The data path itself is just a pipe and has not all the information attached with it. That goes via the control path and that is normally in user space and carries the real important information to make useful analysis of how the data path / context is setup.

From what I am seeing right now is that unless you have a method to also feed the control path into your GSMTAPv3, then this is rather useless. The majority of the debugging is really done for the control path. For oFono that is OFONO_DEBUG=1 environment variable and while it works it is not the most elegant solution. I would love to feed that into a generic debugging / tap that you can read out later.

As a side note, for Bluetooth we created a path where the bluetoothd can feed back its control debugging data back into the Bluetooth monitor in the kernel to allow combined userspace, mgmt and HCI tracing. Some really nasty issues could only be triaged by having all the meta data with a common timestamp.

Regards

Marcel

  parent reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-09 13:50 Johannes Berg
     [not found] ` <CAPEnp=bHTVARr7WA9Qkq4=y7kk8_FLWhrkqKOEXubMO4X=BHCw@mail.gmail.com>
     [not found]   ` <CAPEnp=bHTVARr7WA9Qkq4=y7kk8_FLWhrkqKOEXubMO4X=BHCw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-04-10  7:23     ` Johannes Berg
     [not found]       ` <46474c61d7748042cc0a1f23773186786020638e.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-10  7:57         ` Marcel Holtmann [this message]
2019-04-10 23:45         ` Harald Welte
     [not found]       ` <6F1998DC-EFD2-4145-BD81-A80F9DC7ED2D@holtmann.org>
     [not found]         ` <6F1998DC-EFD2-4145-BD81-A80F9DC7ED2D-kz+m5ild9QBg9hUCZPvPmw@public.gmane.org>
2019-04-12 12:12           ` Johannes Berg
     [not found]             ` <1d64c578cd5b254d301cf1cac82f32a062916888.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-12 19:49               ` Marcel Holtmann
     [not found]             ` <D4D12CF9-9CE5-46FB-9738-F89DB6B6F9EA@holtmann.org>
     [not found]               ` <D4D12CF9-9CE5-46FB-9738-F89DB6B6F9EA-kz+m5ild9QBg9hUCZPvPmw@public.gmane.org>
2019-04-15  9:11                 ` Johannes Berg
     [not found]                   ` <92e8e142b6d441c1c995abc57d64ad7b7747a688.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-15 10:29                     ` Bjørn Mork
     [not found]                       ` <87d0ln1s0a.fsf-3F4PFWf5pNjpjLOzFPqGjWGXanvQGlWp@public.gmane.org>
2019-04-15 10:41                         ` Johannes Berg
     [not found]       ` <20190410234555.GO25552@nataraja>
2019-04-12 17:15         ` Johannes Berg
     [not found]           ` <f0a64bb751b8c601f58130a7f3a3158d70f18f63.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-12 19:54             ` Guy Harris
2019-04-13  7:12             ` Harald Welte
2019-04-13  7:49               ` Guy Harris
     [not found]           ` <196E881D-AB4A-4569-9C1F-5BCB41FE832F@alum.mit.edu>
     [not found]             ` <196E881D-AB4A-4569-9C1F-5BCB41FE832F-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2019-04-12 22:47               ` Guy Harris
     [not found]                 ` <1D6FE33B-DC15-47D8-A1AD-E95608300FDC-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2019-04-13  6:41                   ` Harald Welte
     [not found]                 ` <20190413064152.GB24451@nataraja>
2019-04-13  7:36                   ` Guy Harris
     [not found] ` <cf07ae24c436f92769f9289d208f01846ebe8826.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-10  6:35   ` Vadim Yanitskiy
2019-04-10 23:32   ` Harald Welte
2019-04-12 12:24     ` Johannes Berg
     [not found]       ` <1462659018bc40830efbe2348791b8df45b54cff.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-12 19:48         ` Guy Harris
2019-04-13  7:35         ` Harald Welte
     [not found]       ` <20190413073505.GD24451@nataraja>
2019-04-13  7:55         ` Guy Harris
2019-04-15  9:26         ` Johannes Berg
     [not found]       ` <1089142F-2966-4C41-921B-465FBA721E79@alum.mit.edu>
     [not found]         ` <1089142F-2966-4C41-921B-465FBA721E79-FrUbXkNCsVf2fBVCVOL8/A@public.gmane.org>
2019-04-15  9:28           ` Johannes Berg

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='6F1998DC-EFD2-4145-BD81-A80F9DC7ED2D__286.812269926884$1554887780$gmane$org@holtmann.org' \
    --to=marcel-kz+m5ild9qbg9huczpvpmw@public.gmane.org \
    --cc=aleksander-Dvg4H30XQSRVIjRurl1/8g@public.gmane.org \
    --cc=axilirator-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
    --cc=bjorn-yOkvZcmFvRU@public.gmane.org \
    --cc=dcbw-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
    --cc=johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org \
    --cc=laforge-TgoAw6mPHtdg9hUCZPvPmw@public.gmane.org \
    --cc=linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=openbsc-qjLDD68F18N4m7O/Vxda39i2O/JbrIOy@public.gmane.org \
    --cc=radiotap-S783fYmB3Ccdnm+yROfE0A@public.gmane.org \
    --cc=stranche-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org \
    --cc=subashab-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

RadioTap Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/radiotap/0 radiotap/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 radiotap radiotap/ https://lore.kernel.org/radiotap \
		radiotap@radiotap.org
	public-inbox-index radiotap

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.netbsd.radiotap


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git