Date: Tue, 27 Apr 2004 08:00:25 -0700 (PDT) From: Archie Cobbs <archie@dellroad.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/63317: make ng_ether(4) support "lower" and "orphans"simultaneously Message-ID: <200404271500.i3RF0PY2012882@freefall.freebsd.org>
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The following reply was made to PR kern/63317; it has been noted by GNATS.
From: Archie Cobbs <archie@dellroad.org>
To: Gleb Smirnoff <glebius@cell.sick.ru>
Cc: Archie Cobbs <archie@dellroad.org>,
Maxim Konovalov <maxim@macomnet.ru>, bzeeb-lists@lists.zabbadoz.net,
FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: kern/63317: make ng_ether(4) support "lower" and "orphans"simultaneously
Date: Tue, 27 Apr 2004 09:18:58 -0500 (CDT)
Gleb Smirnoff wrote:
> A> OK, then this is a change in semantics: whereas before, connecting
> A> to lower meant always getting all packets, now connecting to lower
> A> means always getting all packets UNLESS somebody else is connected
> A> to orphans... could be a completely different and unknown process.
>
> It is said in current manpage, that ng_ether sends all packets to lower,
> however code reveals the truth. Here is a sniplet from ng_ether_input_orphan(),
> which is a hook called by ethernet stack:
>
> /* If "orphan" hook not connected, let packet continue */
> if (priv->lower == NULL || !priv->lowerOrphan) {
> m_freem(m);
> return;
> }
What is your point? This function is only called for orphan packets.
In the current code, if the 'lower' hook is connected, this function will
never be called (all packets will get sent to 'lower') (note: in the current
code, 'priv->lower' is used for both 'lower' and 'orphans' hooks).
> To make sure, I've made an experiment. I have a notebook in a network where many IPX
> broadcasts live. So I typed:
>
> + mkpeer fxp0: etf lower downstream
> + name fxp0:lower etf
> + connect etf: dummy ipx
> + msg etf: setfilter { matchhook="ipx" ethertype=0x8137 }
>
> I've waited for half a minute, and no packets arrived. Then, I've typed:
Is this with your modified node? If so, then it demonstrates how you have
changed the semantics.
You should see ALL packets on the 'lower' hook. This has been working fine
for years in the current code.
Try a simpler experiment: "connect fxp0: dummy lower" and you should
see ALL packets, including IPX packets.
> A> To preserve the existing behavior, the node would need to duplicate
> A> the orphanable packets and send them to BOTH connected hooks.
>
> So behavior didn't change. Even we have found some inexactitude in
> manpage.
The current behavior is: if node X is connected to 'lower', then
ALL packets received from the hardware are delivered to node X.
It appears you have changed this (?)
-Archie
__________________________________________________________________________
Archie Cobbs * CTO, Awarix * http://www.awarix.com
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