linux-kernel - [RFC PATCH] lro: ip fragment checking

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Date:	Mon, 24 Nov 2008 16:56:52 +0100
From:	Jan-Bernd Themann <ossthema@...ibm.com>
To:	netdev@...r.kernel.org
CC:	linux-kernel@...r.kernel.org, tklein@...ibm.com,
	Christoph Raisch <raisch@...ibm.com>, jb.billaud@...il.com,
	hering2@...ibm.com
Subject: [RFC PATCH] lro: ip fragment checking

Currently there is no checking in the LRO receive path whether
TCP packets are ip fragmented. We should not consider
those packets for aggregation.
I'm not sure if this checking is actually required. Does anyone
know if it is possible to get fragmented TCP packets without
the tcp stack changing the MSS size?
This patch introduces explicit checking. Any objections?

Regards,

Jan-Bernd

---



 net/ipv4/inet_lro.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/inet_lro.c b/net/ipv4/inet_lro.c
index cfd034a..1f9159d 100644
--- a/net/ipv4/inet_lro.c
+++ b/net/ipv4/inet_lro.c
@@ -64,6 +64,9 @@ static int lro_tcp_ip_check(struct iphdr *iph, struct tcphdr *tcph,
 	if (iph->ihl != IPH_LEN_WO_OPTIONS)
 		return -1;
 
+	if (iph->frag_off & IP_MF)
+		return -1;
+
 	if (tcph->cwr || tcph->ece || tcph->urg || !tcph->ack
 	    || tcph->rst || tcph->syn || tcph->fin)
 		return -1;
-- 
1.5.5




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