From owner-freebsd-stable@FreeBSD.ORG  Wed Aug 11 11:53:12 2010
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 70FAC106564A;
	Wed, 11 Aug 2010 11:53:12 +0000 (UTC)
	(envelope-from luigi@onelab2.iet.unipi.it)
Received: from onelab2.iet.unipi.it (onelab2.iet.unipi.it [131.114.59.238])
	by mx1.freebsd.org (Postfix) with ESMTP id 3A5F38FC0A;
	Wed, 11 Aug 2010 11:53:12 +0000 (UTC)
Received: by onelab2.iet.unipi.it (Postfix, from userid 275)
	id F0FDA73098; Wed, 11 Aug 2010 13:47:29 +0200 (CEST)
Date: Wed, 11 Aug 2010 13:47:29 +0200
From: Luigi Rizzo <rizzo@iet.unipi.it>
To: stable@freebsd.org
Message-ID: <20100811114729.GA83355@onelab2.iet.unipi.it>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.4.2.3i
Cc: net@freebsd.org
Subject: 8.1R: ppp default route uses wrong Netif (with pppoe)
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>, 
	<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
	<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 11 Aug 2010 11:53:12 -0000

Hi,
I found the following problem with ppp after upgrading to 8.1

I am using ppp -ddial -nat ... over pppoe.  The entry in ppp.conf has
these lines (plus others not relevant here):

    my-provider:
        set line PPPoE:nfe0
        ...
        add default HISADDR

Up to 7.2 this sufficed to establish a route using 'tun0' as the device

    Destination        Gateway            Flags    Refs      Use  Netif Expire
    default            81.174.0.1         UGS         0     1885   tun0

With the upgrade to 8.1R the default route points to 'nfe0', i.e. the
device used to talk pppoe, instead of tun0.
This causes a number of failures which prevent operation.

I am not sure though whether the bug is in PPP or in the kernel,
and why ppp now uses the wrong device to install the route entry.

A functional workaround is the following (note you need all three lines!):

        add default HISADDR
        shell route delete default
        shell route add default -interface INTERFACE

where the first line installs the bogus entry but supplies a default
address for outgoing packets, and the other two entries fix
the interface.

I tried to remove the 'add default HISADDR' but it does not seem
to work -- tcpdump shows outgoing packets carrying 0.0.0.0 as src-ip,
which prevents replies from coming back.

I'll submit a PR later, but would be curious to know if someone
has ideas on what could be a proper fix.

cheers
luigi