netdev - [PATCH] tcp: allow user to create repair socket without window probes

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Message-Id: <1531258270-1046-1-git-send-email-sbaranoff@gmail.com>
Date:   Tue, 10 Jul 2018 17:31:10 -0400
From:   Stefan Baranoff <sbaranoff@...il.com>
To:     netdev@...r.kernel.org
Cc:     Andrey Vagin <avagin@...tuozzo.com>,
        Pavel Emelyanov <xemul@...tuozzo.com>,
        Stefan Baranoff <sbaranoff@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        "David S. Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>
Subject: [PATCH] tcp: allow user to create repair socket without window probes

Under rare conditions where repair code may be used it is possible that
window probes are either unnecessary or undesired. If the user knows that
window probes are not wanted or needed this change allows them to skip
sending them when a socket comes out of repair.

Signed-off-by: Stefan Baranoff <sbaranoff@...il.com>
---
 net/ipv4/tcp.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index e7b53d2a..728ae7a 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2821,14 +2821,16 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
 	case TCP_REPAIR:
 		if (!tcp_can_repair_sock(sk))
 			err = -EPERM;
-		else if (val == 1) {
-			tp->repair = 1;
+		/* 1 for normal repair, 2 for no window probes */
+		else if (val == 1 || val == 2) {
+			tp->repair = val;
 			sk->sk_reuse = SK_FORCE_REUSE;
 			tp->repair_queue = TCP_NO_QUEUE;
 		} else if (val == 0) {
 			tp->repair = 0;
 			sk->sk_reuse = SK_NO_REUSE;
-			tcp_send_window_probe(sk);
+			if (tp->repair == 1)
+				tcp_send_window_probe(sk);
 		} else
 			err = -EINVAL;
 
-- 
1.8.3.1