From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] tcp: don't include Fast Open option in SYN-ACK on pure SYN-data Date: Mon, 09 Feb 2015 14:27:32 -0800 (PST) Message-ID: <20150209.142732.243638519161010259.davem@redhat.com> References: <1423514123-6825-1-git-send-email-ycheng@google.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: edumazet@google.com, ncardwell@google.com, netdev@vger.kernel.org To: ycheng@google.com Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44145 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761222AbbBIW1f (ORCPT ); Mon, 9 Feb 2015 17:27:35 -0500 In-Reply-To: <1423514123-6825-1-git-send-email-ycheng@google.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Yuchung Cheng Date: Mon, 9 Feb 2015 12:35:23 -0800 > If a server has enabled Fast Open and it receives a pure SYN-data > packet (without a Fast Open option), it won't accept the data but it > incorrectly returns a SYN-ACK with a Fast Open cookie and also > increments the SNMP stat LINUX_MIB_TCPFASTOPENPASSIVEFAIL. > > This patch makes the server include a Fast Open cookie in SYN-ACK > only if the SYN has some Fast Open option (i.e., when client > requests or presents a cookie). > > Signed-off-by: Yuchung Cheng > Acked-by: Neal Cardwell > Acked-by: Eric Dumazet Applied.