From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754467AbdBEUQE (ORCPT + 2 others); Sun, 5 Feb 2017 15:16:04 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:27744 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753327AbdBETYA (ORCPT ); Sun, 5 Feb 2017 14:24:00 -0500 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Eric Dumazet , Yuchung Cheng , Neal Cardwell , "David S . Miller" , Willy Tarreau Subject: [PATCH 3.10 232/319] tcp: properly scale window in tcp_v[46]_reqsk_send_ack() Date: Sun, 5 Feb 2017 20:20:54 +0100 Message-Id: <1486322541-8206-133-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1486322541-8206-1-git-send-email-w@1wt.eu> References: <1486322541-8206-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Eric Dumazet commit 20a2b49fc538540819a0c552877086548cff8d8d upstream. When sending an ack in SYN_RECV state, we must scale the offered window if wscale option was negotiated and accepted. Tested: Following packetdrill test demonstrates the issue : 0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 // Establish a connection. +0 < S 0:0(0) win 20000 +0 > S. 0:0(0) ack 1 win 28960 +0 < . 1:11(10) ack 1 win 156 // check that window is properly scaled ! +0 > . 1:1(0) ack 1 win 226 Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Cc: Neal Cardwell Acked-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau --- net/ipv4/tcp_ipv4.c | 3 ++- net/ipv6/tcp_ipv6.c | 8 +++++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 11f27a4..5401fbf 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -824,7 +824,8 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, */ tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, - tcp_rsk(req)->rcv_nxt, req->rcv_wnd, + tcp_rsk(req)->rcv_nxt, + req->rcv_wnd >> inet_rsk(req)->rcv_wscale, tcp_time_stamp, req->ts_recent, 0, diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 41c026f..d823738 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -902,8 +902,14 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, struct request_sock *req) { + /* RFC 7323 2.3 + * The window field (SEG.WND) of every outgoing segment, with the + * exception of segments, MUST be right-shifted by + * Rcv.Wind.Shift bits: + */ tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, - req->rcv_wnd, tcp_time_stamp, req->ts_recent, + req->rcv_wnd >> inet_rsk(req)->rcv_wscale, + tcp_time_stamp, req->ts_recent, tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0); } -- 2.8.0.rc2.1.gbe9624a