linux-kernel - [PATCH net] tcp: Fix broken repair socket window probe patch

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Date:   Sat, 14 Jul 2018 21:54:09 -0400
From:   Stefan Baranoff <sbaranoff@...il.com>
To:     unlisted-recipients:; (no To-header on input)
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>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net] tcp: Fix broken repair socket window probe patch

Correct previous bad attempt at allowing sockets to come out of TCP
repair without sending window probes. To avoid changing size of
the repair variable in struct tcp_sock, this lets the decision for
sending probes or not to be made when coming out of repair by
introducing two ways to turn it off.

Fixes: 70b7ff130224 ("tcp: allow user to create repair socket without window probes")
Signed-off-by: Stefan Baranoff <sbaranoff@...il.com>
---
 include/uapi/linux/tcp.h |  4 ++++
 net/ipv4/tcp.c           | 12 +++++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 29eb659..e3f6ed8 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -127,6 +127,10 @@ enum {
 
 #define TCP_CM_INQ		TCP_INQ
 
+#define TCP_REPAIR_ON		1
+#define TCP_REPAIR_OFF		0
+#define TCP_REPAIR_OFF_NO_WP	-1	/* Turn off without window probes */
+
 struct tcp_repair_opt {
 	__u32	opt_code;
 	__u32	opt_val;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8e5e2ca..9163fb1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2824,15 +2824,17 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
 		if (!tcp_can_repair_sock(sk))
 			err = -EPERM;
 		/* 1 for normal repair, 2 for no window probes */
-		else if (val == 1 || val == 2) {
-			tp->repair = val;
+		else if (val == TCP_REPAIR_ON) {
+			tp->repair = 1;
 			sk->sk_reuse = SK_FORCE_REUSE;
 			tp->repair_queue = TCP_NO_QUEUE;
-		} else if (val == 0) {
+		} else if (val == TCP_REPAIR_OFF) {
+			tp->repair = 0;
+			sk->sk_reuse = SK_NO_REUSE;
+			tcp_send_window_probe(sk);
+		} else if (val == TCP_REPAIR_OFF_NO_WP) {
 			tp->repair = 0;
 			sk->sk_reuse = SK_NO_REUSE;
-			if (tp->repair == 1)
-				tcp_send_window_probe(sk);
 		} else
 			err = -EINVAL;
 
-- 
1.8.3.1