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Wireshark-dev: Re: [Wireshark-dev] Patch to epan/dissectors/packet-lapd.c, some-one please appl

From: Rolf Fiedler <rolf.fiedler@xxxxxxxxxxxxx>
Date: Thu, 21 Sep 2006 20:49:30 +0200
Hi Jaap,

thank you for your reply. I understand your concern, so I would like to present my view of things. It would be best if SVN user etxrab could also comment on this, after all her/his patch broke network/user display on ISDN captures.

The traditional ethereal convention is that the device capturing the data sits on the user side of an ISDN link, so SENT means sent by TE (user) and RECV means sent by NT (network). This conventions is quite reasonable, since most wireshark users capture on the user side.

The patch by etxrab added the possibility to be either on the network or on the user side, but only for a specific capture type. For all other cases, the old behaviour should stay.

The code is like
if(pinfo->fd->lnk_t == WTAP_ENCAP_LINUX_LAPD) {
check if capturing on net or user side and setting src and dst accordingly. this was added for vISDN capturing by adding a new capture type to libpcap
} else {
the other case is for all old isdn captures and should have stayed the same.
  however, it was swapped, I assume accidentially
  here is should always be
  if SENT: src=User, dst=Network
  if RECV: src=Network, dst=User
}

extrab, please confirm this description.
I hope this helps to clear up the situation.
By the way, I know the person who posted bug 965 personally (but we haven't spoken about this issue). My patch from bug 1106 would also close bug 965, both bugs are essentially the same.

Greetings,
Rolf

PS: another way of looking at this issue: the patch by extrab swapped net/user for all existing users of packet-lapd and so now shows false information. It was ok before, since March this year Network and User are swapped.
Hi Rolf,

It would be nice if we could figure out why these swaps have taken place.
There's also a bug on Q.931 about this (bug 965), which is also not yet
explained by the parties involved.

The patch isn't the problem, it's avoiding a ping pong game what is user
and what is network side.

Thanx,
Jaap


On Mon, 18 Sep 2006, Rolf Fiedler wrote:

> Hi,
>
> I opened bug 1106 in bugzilla, and I attached a patch to fix the bug in
> the same bug-report. I thought that might be the easiest way to get a
> patch applied. But maybe that was the wrong way to do that. So my
> questions are:
> a) what is the correct way to contribute patches?
> b) could someone please have a look at bug 1106 and apply the patch and
> close the bug?
> c) what is needed to get svn commit permissions?
>
> At the moment I build and test on Linux and don't have the proper setup
> to build Win32 installers. So I hope the change will be included in the
> next release.
>
> We have plans to add ASN.1 decoding of some commonly found FACILITY
> messages to the lapd dissector. For that it would be good to have a way
> to commit the changes.
>