OpenBSC

openbsc@lists.osmocom.org

13 participants
4246 discussions

Abis 12.21 OML plugin for wireshark
by Harald Welte 03 Jul '09

03 Jul '09

Hi all! As some of you might have seen from the various git commit messages, I spent quite a bit of time to implement a GSM 12.21 (A-bis OML) plugin for wireshark from scratch. It's available in our git repository at /wireshark/abis_oml.patch My main focus has been the parsing of the ip.access vendor-specific extensions to 12.21, as that part is much harder than just implementing what's written in TS 12.21 itself. One of the things that it can now decode is decoding of the 'network listen' functionality implemented as 12.21 'perform test'. Using this, you can scan over all ARFCN and report the rx level (good for determining an unused channel at your current location), or you can actually decode the BCCH information of all cells in your vicinity. This is just the wireshark plugin. I did not write any FOSS code for actually starting those tests, you still need some non-free software for that. However, looking at the pcap file I sent some time ago and at this wireshark plugin, anyone interested should be able to implement this very quickly, maybe as an addition to ipaccess-config. Due to my current lack of access to BS-11 hardware, the plugin was not yet tested against it. If anyone can do some testing in this regard, it would be much appreciated. Alternatively, if somebody can send me some BS11 pcap files (maybe just of OpenBSC starting up), I can make sure to fix it. I'm planning to do some more work regarding cleanup and feature-completeness of the plugin before submitting it mainline to wireshark. However, the Abis-IP plugin should be quite complete and I'll plan to submit it really soon now. Regards, -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

1 0

AW: Patch 39: WAS: Re: patches again
by Andreas.Eversberg 29 Jun '09

29 Jun '09

> I think we can just move the schedule_reject from two lines below the if to the top. What do you think? > 2.) The patch changes the policy from delayed reject (to not make the MS come > back immediately) to a direct one. What is the reasoning? hi holger, 1. just move it to the top. 2. you are right. only we need to restart the timer and exit, on location update with TMSI. also i was concerned about loosing link to mobile. in this case we get a timeout, so only the first 3 lines make sense. anyway i will test it and see if i missed to explain an importaint reason. regards, andreas

1 0

AW: MSC split out progress
by Andreas.Eversberg 29 Jun '09

29 Jun '09

> One thing that keeps me from pushing (after having tested) is the following observation. For going from layer3 to layer4 we currently have a queue, for my patches when going from layer2 to layer3 I have a direct callback. Should I change that to use the same queuing approach? hi holger, for me it is very hard to explain, but i will try... - bsc = lower layer (signalling) - msc = upper layer (application) actually we need a queue in only one direction, if we link two finite state machines. (or in our case link two instances of transactions using mncc.c). during an bsc-event, when a message from bsc is sent to msc, the bsc might do some processing right after sending the message. without a queue, the msc could reply directly to that message (with a function call to msc) which may change the state machine of bsc, while bsc is still processing the first event... (race condition) an up-queue from bsc to msc will fix that problem. msc will only process messages, if bsc has finished it's processing of events. in case of a message from msc to bsc, we also don't have that problem, even without a queue. if msc sends a message directly down to bsc (using a function call), an eventually direct reply is queued in the up-queue, so msc can finish processing the first event before processing the message in the up-queue. it does not matter if the queue is for messages from bsc to msc, or from msc to bsc, but at least we need one queue. it may happen that a message is dequeued, but the call instance is already gone. in this case the other layer (bsc or msc) should ignore it. this is why the call reference is used instead of a memory pointer. also it must be unique all the (run-)time. regards, andreas

1 0

AW: abnormal channel release WAS: Re: patches again
by Andreas.Eversberg 29 Jun '09

29 Jun '09

hi holger, i can do that soon. part 3 just removes the if-condition. i missed to remove it after testing. i will fix it in the forthcomming splitted patches. regards, andreas > Okay. As stupid as it might sound please split that into three patches. > 1.) Fixing my stupidity in gsm0408_handle_lchan_signal!!! sorry for making you suffer from it and thanks for fixing it. > 2.) static int rsl_rx_rll_err_ind(struct msgb *msg) > 3.) Explain why > +// if (msg->lchan->use_count > 0) { > +// } > is a good change and should be applied?

1 0

WG: patches again
by Andreas.Eversberg 29 Jun '09

29 Jun '09

> I don't use mISDN on Linux (I use Cygwin on Windows with my custom driver). However I had to adjust my custom driver to see the measurement reports in bsc_hack. The reason is that the measurement reports are sent as LAPD UI-Frames and not as LAPD I-Frames and I did not yet take care of UI-Frames. Maybe there is a similar problem with mISDN and UI-Frames. hi dieter, this is indeed a good thing to check. i can enable frame debugging on hfc-e1, so i can see every frame in hex. also i can sniff frames using an mISDN userland tool. with that i can see if there are any frames. if so i will check why the driver does not report UI frames in this case, and fix it.. regards, andreas

1 0

Re: patches again
by Holger Freyther 29 Jun '09

29 Jun '09

On Sunday 28 June 2009 18:47:31 Andreas.Eversberg wrote: > patch 38: still i use this little hacked install patch to install > library and include files, so other applications like LCR can use > openbsc without refering to the openbsc source directory. i use that > install-hook, because i don't know much about autoconf. maybe there is a > better way to do that. There is. Currently all the libraries are noinst libraries.. I did sent a patch to the mailinglist you could attempt to extent and make ready? z.

1 0

MSC split out progress
by Holger Freyther 29 Jun '09

29 Jun '09

Hey, just a small head up. I rebased the holger/msc branch and also moved the mncc bits into the libmsc. I'm currently in Essen and should be able to test these patches tomorrow. One thing that keeps me from pushing (after having tested) is the following observation. For going from layer3 to layer4 we currently have a queue, for my patches when going from layer2 to layer3 I have a direct callback. Should I change that to use the same queuing approach? holger

1 0

move tall_bsc_ctx WAS: Re: patches again
by Holger Freyther 29 Jun '09

29 Jun '09

On Sunday 28 June 2009 18:47:31 Andreas.Eversberg wrote: > patch 41: the pointer "tall_bsc_ctx" belongs to the gsm_data.c file, not > to include file. seems sensible.

1 0

abnormal channel release WAS: Re: patches again
by Holger Freyther 29 Jun '09

29 Jun '09

On Sunday 28 June 2009 18:47:31 Andreas.Eversberg wrote: > patch 40: in case of a channel breakdown, the signal handler for > releasing lchan is called. the wrong pointer was used as lchan. (see > last hunk) also we don't need to check use counter of lchan, if we > receive an "cause 22 error". the lchan gets released anyway, if use > counter becomes 0. (see first hunk). also i think we can force channel > release when we receive an error indication. this can easily be tested: > remove the battery during active call, then send a message to the mobile > station (hang up on the remote). the message cannot be delivered, so the > BTS send us an error indication, the channels and the call process gets > released. Okay. As stupid as it might sound please split that into three patches. 1.) Fixing my stupidity in gsm0408_handle_lchan_signal!!! sorry for making you suffer from it and thanks for fixing it. 2.) static int rsl_rx_rll_err_ind(struct msgb *msg) 3.) Explain why +// if (msg->lchan->use_count > 0) { +// } is a good change and should be applied? thanks

1 0

Re: patches again
by Dieter Spaar 29 Jun '09

29 Jun '09

Hello Harald, On Sun, 28 Jun 2009 23:23:01 +0200, "Harald Welte" <laforge(a)gnumonks.org> wrote: > > However, since Dieter has been seeing the measurement reports, I would hope he > is able to verify wether it works for him with the current git version of > OpenBSC, or what kind of changes he needs to make it work. Sorry :( I tested it with the git version from yesterday. The TRX0 is configured properly, I can see that the attributes are set as they should. I can also see the measurement reports in my custom traces (I set NM_ATT_BS11_RADIO_MEAS_GRAN to 0x05). I don't use mISDN on Linux (I use Cygwin on Windows with my custom driver). However I had to adjust my custom driver to see the measurement reports in bsc_hack. The reason is that the measurement reports are sent as LAPD UI-Frames and not as LAPD I-Frames and I did not yet take care of UI-Frames. Maybe there is a similar problem with mISDN and UI-Frames. One other thing is that decoding the measurement report might not yet work properly, bsc_hack says that the reports are invalid but for the MA10 Analyzer they are fine. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

2 1

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

OpenBSC