[PATCH net-next] tcp: diag: add support for TIME_WAIT sockets to tcp_abort()

From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com,
	Eric Dumazet <edumazet@google.com>,
	Muhammad Usama Anjum <usama.anjum@collabora.com>
Subject: [PATCH net-next] tcp: diag: add support for TIME_WAIT sockets to tcp_abort()
Date: Mon, 27 Jun 2022 12:10:38 +0000	[thread overview]
Message-ID: <20220627121038.226500-1-edumazet@google.com> (raw)

Currently, "ss -K -ta ..." does not support TIME_WAIT sockets.

Issue has been raised at least two times in the past [1] [2]
it is time to fix it.

[1] https://lore.kernel.org/netdev/ba65f579-4e69-ae0d-4770-bc6234beb428@gmail.com/
[2] https://lore.kernel.org/netdev/CANn89i+R9RgmD=AQ4vX1Vb_SQAj4c3fi7-ZtQz-inYY4Sq4CMQ@mail.gmail.com/T/

While we are at it, use inet_sk_state_load() while tcp_abort()
does not hold a lock on the socket.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
---
 net/ipv4/tcp.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f7309452bdcec095fd7d923089881f0b99c97df7..d2ca56aa18eb35b314ff02bbece8c3e713fe57bd 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4531,16 +4531,24 @@ EXPORT_SYMBOL_GPL(tcp_done);
 
 int tcp_abort(struct sock *sk, int err)
 {
-	if (!sk_fullsock(sk)) {
-		if (sk->sk_state == TCP_NEW_SYN_RECV) {
-			struct request_sock *req = inet_reqsk(sk);
+	int state = inet_sk_state_load(sk);
 
-			local_bh_disable();
-			inet_csk_reqsk_queue_drop(req->rsk_listener, req);
-			local_bh_enable();
-			return 0;
-		}
-		return -EOPNOTSUPP;
+	if (state == TCP_NEW_SYN_RECV) {
+		struct request_sock *req = inet_reqsk(sk);
+
+		local_bh_disable();
+		inet_csk_reqsk_queue_drop(req->rsk_listener, req);
+		local_bh_enable();
+		return 0;
+	}
+	if (state == TCP_TIME_WAIT) {
+		struct inet_timewait_sock *tw = inet_twsk(sk);
+
+		refcount_inc(&tw->tw_refcnt);
+		local_bh_disable();
+		inet_twsk_deschedule_put(tw);
+		local_bh_enable();
+		return 0;
 	}
 
 	/* Don't race with userspace socket closes such as tcp_close. */
-- 
2.37.0.rc0.161.g10f37bed90-goog

