From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fan Du Subject: [PATCHv3 net-next 3/4] ipv4: shrink current mss for tcp PMTU blackhole detection Date: Sat, 28 Feb 2015 11:23:04 +0800 Message-ID: <1425093785-27380-4-git-send-email-fan.du@intel.com> References: <1425093785-27380-1-git-send-email-fan.du@intel.com> Cc: edumazet@google.com, davem@davemloft.net, netdev@vger.kernel.org, fengyuleidian0615@gmail.com To: johnwheffner@gmail.com Return-path: Received: from mga03.intel.com ([134.134.136.65]:46020 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752449AbbB1D1y (ORCPT ); Fri, 27 Feb 2015 22:27:54 -0500 In-Reply-To: <1425093785-27380-1-git-send-email-fan.du@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: 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); } -- 1.7.1