From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Steffen Klassert , "David S. Miller" Subject: [ 69/85] ipv4: Dont create nh exeption when the device mtu is smaller than the reported pmtu Date: Thu, 25 Oct 2012 17:06:27 -0700 Message-Id: <20121026000038.054146021@linuxfoundation.org> In-Reply-To: <20121026000031.107227138@linuxfoundation.org> References: <20121026000031.107227138@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steffen Klassert [ Upstream commit 7f92d334ba19a0d8e96f8f8f092219553367d921 ] When a local tool like tracepath tries to send packets bigger than the device mtu, we create a nh exeption and set the pmtu to device mtu. The device mtu does not expire, so check if the device mtu is smaller than the reported pmtu and don't crerate a nh exeption in that case. Signed-off-by: Steffen Klassert Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/route.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -909,6 +909,9 @@ static void __ip_rt_update_pmtu(struct r struct dst_entry *dst = &rt->dst; struct fib_result res; + if (dst->dev->mtu < mtu) + return; + if (mtu < ip_rt_min_pmtu) mtu = ip_rt_min_pmtu;