From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zheng Li Subject: [PATCH] ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output Date: Thu, 8 Dec 2016 22:48:51 +0800 Message-ID: <1481208531-2889-1-git-send-email-lizheng043@gmail.com> Cc: allen.y.zhao@ericsson.com, hua.lv@ericsson.com, james.z.li@ericsson.com To: netdev@vger.kernel.org, davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net Return-path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:35605 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932171AbcLHOtU (ORCPT ); Thu, 8 Dec 2016 09:49:20 -0500 Received: by mail-pf0-f194.google.com with SMTP id i88so13057914pfk.2 for ; Thu, 08 Dec 2016 06:49:15 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: From: zheng li There is an inconsitent conditional judgement in __ip_append_data and ip_finish_output functions, the variable length in __ip_append_data just include the length of applicatoin'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 cuase some particular applicatoin's udp payload whose length is between (MTU - IP Header) and MTU were framented by ip_fragment even though the rst->dev support UFO features. 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