From patchwork Thu Feb 26 03:49:25 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fan Du X-Patchwork-Id: 443787 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 39830140111 for ; Thu, 26 Feb 2015 14:54:23 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753145AbbBZDyU (ORCPT ); Wed, 25 Feb 2015 22:54:20 -0500 Received: from mga02.intel.com ([134.134.136.20]:41794 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752835AbbBZDyM (ORCPT ); Wed, 25 Feb 2015 22:54:12 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP; 25 Feb 2015 19:54:11 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,650,1418112000"; d="scan'208";a="683587285" Received: from dufan-optiplex-9010.bj.intel.com ([10.238.155.116]) by fmsmga002.fm.intel.com with ESMTP; 25 Feb 2015 19:54:08 -0800 From: Fan Du To: johnwheffner@gmail.com Cc: edumazet@google.com, davem@davemloft.net, netdev@vger.kernel.org, fengyuleidian0615@gmail.com Subject: [PATCHv2 net-next 3/4] ipv4: shrink current mss for tcp PMTU blackhole detection Date: Thu, 26 Feb 2015 11:49:25 +0800 Message-Id: <1424922566-6787-4-git-send-email-fan.du@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1424922566-6787-1-git-send-email-fan.du@intel.com> References: <1423815405-32644-1-git-send-email-fan.du@intel.com> <1424922566-6787-1-git-send-email-fan.du@intel.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Reducing current tcp mss instead of search_low will make more sense, as current tcp mss still got lost. In addition, rename tcp_mtu_probing to tcp_blackhole_probe to clearify confusion between tcp_mtu_probing and tcp_mtu_probe. Signed-off-by: Fan Du --- net/ipv4/tcp_timer.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 0732b78..3465175 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -99,7 +99,8 @@ static int tcp_orphan_retries(struct sock *sk, int alive) return retries; } -static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) +static void tcp_blackhole_probe(struct inet_connection_sock *icsk, + struct sock *sk) { struct net *net = sock_net(sk); @@ -113,7 +114,8 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); int mss; - mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1; + /* try mss smaller than current mss */ + mss = tcp_current_mss(sk) >> 1; mss = min(net->ipv4.sysctl_tcp_base_mss, mss); mss = max(mss, 68 - tp->tcp_header_len); icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); @@ -176,7 +178,7 @@ static int tcp_write_timeout(struct sock *sk) } else { if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) { /* Black hole detection */ - tcp_mtu_probing(icsk, sk); + tcp_blackhole_probe(icsk, sk); dst_negative_advice(sk); }