kern/63317: make ng_ether(4) support "lower" and "orphans"simultaneously

[Archie Cobbs]

The following reply was made to PR kern/63317; it has been noted by GNATS.

From: Archie Cobbs <archie at dellroad.org>
To: Gleb Smirnoff <glebius at cell.sick.ru>
Cc: Archie Cobbs <archie at dellroad.org>,
	Maxim Konovalov <maxim at macomnet.ru>, bzeeb-lists at lists.zabbadoz.net,
	FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: kern/63317: make ng_ether(4) support "lower" and "orphans"simultaneously
Date: Mon, 26 Apr 2004 08:53:23 -0500 (CDT)

 Gleb Smirnoff wrote:
 > A> So just to make sure I understand: the new semantics of having both
 > A> hooks connected is that lower gets all packets and orphans would not 
 > A> see any packets unless packets are also written into the upper hook
 > A> (e.g., if the node connected to lower "passes through" to upper).
 > 
 > No. Lower gets all packets which in normal way would travel into upper
 > protocol stack. Orphans gets all packets which in normal way would be
 > discarded. Nothing depends on behavior of the node connected to lower.
 > 
 > The functionality of hooks does not change at all. The new behavior is
 > the same as in current manpage:
 > 
 >      The lower hook is a connection to the raw Ethernet device.  When con-
 >      nected, all incoming packets are diverted out this hook. 
 > 
 >      The orphans hook is equivalent to lower, except that only unrecognized
 >      packets (that would otherwise be discarded) are written to the hook, and
 >      normal incoming traffic is unaffected.
 > 
 > The only difference is that the sentence
 > 
 >      At most one of orphans and lower may be connected at any time.
 > 
 > is not the truth anymore.
 
 Let me be more specific. Suppose both lower and orphans are connected.
 A packet is received from the Ethernet hardware with ethertype
 0x1234 (i.e., unrecognized). Which hook(s) (lower and/or orphans)
 does that packet get written to?  Then: same question applied to a
 packet received from the upper hook.
 
 -Archie
 
 __________________________________________________________________________
 Archie Cobbs      *        CTO, Awarix        *      http://www.awarix.com