Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754004AbcLLB4W (ORCPT ); Sun, 11 Dec 2016 20:56:22 -0500 Received: from mail-pg0-f68.google.com ([74.125.83.68]:36414 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752452AbcLLB4V (ORCPT ); Sun, 11 Dec 2016 20:56:21 -0500 From: Zheng Li To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net Cc: james.z.li@ericsson.com Subject: [PATCH v2] ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output Date: Mon, 12 Dec 2016 09:56:05 +0800 Message-Id: <1481507765-3684-1-git-send-email-lizheng043@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1431 Lines: 36 From: zheng li There is an inconsistent conditional judgement in __ip_append_data and ip_finish_output functions, the variable length in __ip_append_data just include the length of application's payload and udp header, don't include the length of ip header, but in ip_finish_output use (skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the length of ip header. That causes some particular application's udp payload whose length is between (MTU - IP Header) and MTU were fragmented by ip_fragment even though the rst->dev support UFO feature. Add the length of ip header to length in __ip_append_data to keep consistent conditional judgement as ip_finish_output for ip fragment. Signed-off-by: Zheng Li --- net/ipv4/ip_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 877bdb0..12a0149 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -936,7 +936,7 @@ static int __ip_append_data(struct sock *sk, csummode = CHECKSUM_PARTIAL; cork->length += length; - if (((length > mtu) || (skb && skb_is_gso(skb))) && + if ((((length + fragheaderlen) > mtu) || (skb && skb_is_gso(skb))) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len && (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx) { -- 2.7.4