From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Heffner Subject: [PATCH] [NET] MTU discovery check in ip6_fragment() Date: Wed, 18 Apr 2007 21:07:43 -0400 Message-ID: <11769448654084-git-send-email-jheffner@psc.edu> References: <11746948063923-git-send-email-jheffner@psc.edu> <11769448643248-git-send-email-jheffner@psc.edu> <11769448642649-git-send-email-jheffner@psc.edu> Cc: Patrick McHardy , netdev@vger.kernel.org, John Heffner To: David Miller Return-path: Received: from mailer2.psc.edu ([128.182.66.106]:51446 "EHLO mailer2.psc.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030974AbXDSBHt (ORCPT ); Wed, 18 Apr 2007 21:07:49 -0400 In-Reply-To: <11769448642649-git-send-email-jheffner@psc.edu> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Adds a check in ip6_fragment() mirroring ip_fragment() for packets that we can't fragment, and sends an ICMP Packet Too Big message in response. Signed-off-by: John Heffner --- net/ipv6/ip6_output.c | 13 +++++++++++++ 1 files changed, 13 insertions(+), 0 deletions(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4cfdad4..5a5b7d4 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -567,6 +567,19 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) nexthdr = *prevhdr; mtu = dst_mtu(&rt->u.dst); + + /* We must not fragment if the socket is set to force MTU discovery + * or if the skb it not generated by a local socket. (This last + * check should be redundant, but it's free.) + */ + if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) { + skb->dev = skb->dst->dev; + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); + IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); + kfree_skb(skb); + return -EMSGSIZE; + } + if (np && np->frag_size < mtu) { if (np->frag_size) mtu = np->frag_size; -- 1.5.1.rc3.30.ga8f4-dirty