From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753404Ab2IMV2G (ORCPT ); Thu, 13 Sep 2012 17:28:06 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:22705 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752821Ab2IMV2B (ORCPT ); Thu, 13 Sep 2012 17:28:01 -0400 From: Andrew Vagin To: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Pavel Emelyanov , Andrew Vagin , "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy Subject: [PATCH] tcp: restore rcv_wscale in a repair mode Date: Fri, 14 Sep 2012 01:28:07 +0400 Message-Id: <1347571687-3539973-1-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org rcv_wscale is a symetric parameter with snd_wscale. Both this parameters are set on a connection handshake. Without this value a remote window size can not be interpreted correctly, because a value from a packet should be shifted on rcv_wscale. And one more thing is that wscale_ok should be set too. This patch doesn't break a backward compatibility. If someone uses it in a old scheme, a rcv window will be restored with the same bug (rcv_wscale = 0). Cc: David S. Miller Cc: Alexey Kuznetsov Cc: James Morris Cc: Hideaki YOSHIFUJI Cc: Patrick McHardy Acked-by: Pavel Emelyanov Signed-off-by: Andrew Vagin --- net/ipv4/tcp.c | 20 ++++++++++++++++---- 1 files changed, 16 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index df83d74..ed22cd7 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2348,10 +2348,22 @@ static int tcp_repair_options_est(struct tcp_sock *tp, tp->rx_opt.mss_clamp = opt.opt_val; break; case TCPOPT_WINDOW: - if (opt.opt_val > 14) - return -EFBIG; - - tp->rx_opt.snd_wscale = opt.opt_val; + { + union { + struct { + u16 snd_wscale; + u16 rcv_wscale; + }; + u32 raw; + } val = { .raw = opt.opt_val }; + + if (val.snd_wscale > 14 || val.rcv_wscale > 14) + return -EFBIG; + + tp->rx_opt.snd_wscale = val.snd_wscale; + tp->rx_opt.rcv_wscale = val.rcv_wscale; + tp->rx_opt.wscale_ok = 1; + } break; case TCPOPT_SACK_PERM: if (opt.opt_val != 0) -- 1.7.1