mptcp: parse and act on incoming FASTCLOSE option

parse the MPTCP FASTCLOSE subtype.

If provided key matches the local one, schedule the work queue to close
(with tcp reset) all subflows.

The MPTCP socket moves to closed state immediately.

Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 2540d82742ac..cb8b7adf218a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2217,6 +2217,36 @@ static bool mptcp_check_close_timeout(const struct sock *sk)
 	return true;
 }
 
+static void mptcp_check_fastclose(struct mptcp_sock *msk)
+{
+	struct mptcp_subflow_context *subflow, *tmp;
+	struct sock *sk = &msk->sk.icsk_inet.sk;
+
+	if (likely(!READ_ONCE(msk->rcv_fastclose)))
+		return;
+
+	mptcp_token_destroy(msk);
+
+	list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
+		struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+		lock_sock(tcp_sk);
+		if (tcp_sk->sk_state != TCP_CLOSE) {
+			tcp_send_active_reset(tcp_sk, GFP_ATOMIC);
+			tcp_set_state(tcp_sk, TCP_CLOSE);
+		}
+		release_sock(tcp_sk);
+	}
+
+	inet_sk_state_store(sk, TCP_CLOSE);
+	sk->sk_shutdown = SHUTDOWN_MASK;
+	smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+	set_bit(MPTCP_DATA_READY, &msk->flags);
+	set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags);
+
+	mptcp_close_wake_up(sk);
+}
+
 static void mptcp_worker(struct work_struct *work)
 {
 	struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
@@ -2233,6 +2263,9 @@ static void mptcp_worker(struct work_struct *work)
 
 	mptcp_check_data_fin_ack(sk);
 	__mptcp_flush_join_list(msk);
+
+	mptcp_check_fastclose(msk);
+
 	if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
 		__mptcp_close_subflow(msk);