From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timo Teras Subject: Re: [PATCH net v2] ip_tunnels: Use skb-len to PMTU check. Date: Mon, 1 Jul 2013 09:41:32 +0300 Message-ID: <20130701094132.3019afb4@vostro> References: <1372660232-12174-1-git-send-email-pshelar@nicira.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Pravin B Shelar Return-path: Received: from mail-ea0-f181.google.com ([209.85.215.181]:56042 "EHLO mail-ea0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750987Ab3GAGlY (ORCPT ); Mon, 1 Jul 2013 02:41:24 -0400 Received: by mail-ea0-f181.google.com with SMTP id a15so1847100eae.26 for ; Sun, 30 Jun 2013 23:41:23 -0700 (PDT) In-Reply-To: <1372660232-12174-1-git-send-email-pshelar@nicira.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, 30 Jun 2013 23:30:32 -0700 Pravin B Shelar wrote: > In path mtu check, ip header total length works for gre device > but not for gre-tap device. Use skb len which is consistent > for all tunneling types. This is old bug in gre. > This also fixes mtu calculation bug introduced by > commit c54419321455631079c7d (GRE: Refactor GRE tunneling code). > > Reported-by: Timo Teras > Signed-off-by: Pravin B Shelar > --- > v1-v2: > - Fix pmtu set. > - This patch also restructures code which help couple of > improvements I have. Looks good to me. One additional comment below. > diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c > index 7fa8f08..ae5b78c 100644 > --- a/net/ipv4/ip_tunnel.c > +++ b/net/ipv4/ip_tunnel.c > @@ -486,6 +486,53 @@ drop: > } > EXPORT_SYMBOL_GPL(ip_tunnel_rcv); > > +static int tnl_update_pmtu(struct net_device *dev, struct sk_buff > *skb, > + struct rtable *rt, __be16 df) > +{ > + struct ip_tunnel *tunnel = netdev_priv(dev); > + int pkt_size = skb->len - tunnel->hlen; > + int mtu; > + > + if (df) > + mtu = dst_mtu(&rt->dst) - dev->hard_header_len > + - sizeof(struct iphdr) - > tunnel->hlen; > + else > + mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : > dev->mtu; + > + if (skb_dst(skb)) > + skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, > skb, mtu); + Since mtu can change for skb_dst() only if df is set, would it make sense to move the whole update_pmtu call inside if (df) {} block? - Timo