From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Klassert Subject: [PATCH 5/5] ipv4: Don't use the cached pmtu informations for input routes Date: Wed, 23 Nov 2011 13:14:50 +0100 Message-ID: <20111123121450.GE6348@secunet.com> References: <20111123121213.GA6348@secunet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from a.mx.secunet.com ([195.81.216.161]:53469 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754918Ab1KWMOy (ORCPT ); Wed, 23 Nov 2011 07:14:54 -0500 Content-Disposition: inline In-Reply-To: <20111123121213.GA6348@secunet.com> Sender: netdev-owner@vger.kernel.org List-ID: The pmtu informations on the inetpeer are visible for output and input routes. On packet forwarding, we might propagate a learned pmtu to the sender. As we update the pmtu informations of the inetpeer on demand, the original sender of the forwarded packets might never notice when the pmtu to that inetpeer increases. So use the mtu of the outgoing device on packet forwarding instead of the pmtu to the final destination. Signed-off-by: Steffen Klassert --- net/ipv4/route.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 11d1b20..fb47c8f 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1816,15 +1816,15 @@ static unsigned int ipv4_default_advmss(const struct dst_entry *dst) static unsigned int ipv4_mtu(const struct dst_entry *dst) { + const struct rtable *rt = (const struct rtable *) dst; unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); - if (mtu) + if (mtu && rt_is_output_route(rt)) return mtu; mtu = dst->dev->mtu; if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { - const struct rtable *rt = (const struct rtable *) dst; if (rt->rt_gateway != rt->rt_dst && mtu > 576) mtu = 576; -- 1.7.0.4