From nobody Sat Oct 11 08:07:06 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 119583161AC for ; Thu, 18 Sep 2025 17:15:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758215720; cv=none; b=pfM5h9v7dtx+pfQtICblt3tYpKXJawkBg+nlC48Jbmrv4T5+mW98wYOpw9N38Nq03ZMeQCgVjHI0aTcxr7Fr8a4JIvy9sFkdq+t7lURREOpfpHZ94GfAYdXR9L8pXhbPdI5Sj0nSKOh9zf2BiElv1tQS43rw5W+QrjTjEF8Le88= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758215720; c=relaxed/simple; bh=Kcnh3IB3f3aXnG50sE8Mk7fnAzZaLwhRrM5e/XWqAnE=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=LZDV4Wwqsl44FyPnXOGVAcIgKlQAg4CI1Wqo6P7nIyYjV+/G4uIIjscelUo49GUCR5MRBHDoYfEDXrmsflhXKqp4WSeWv3NwD2Cnf8HvuMv2S+rFffnMnLrbu0oP8Y2I9B9q2+ld7QcN2lsS0lxQ7KCb7nLv6EMuOC7hRTu9Eo0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Dlw5qVD6; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Dlw5qVD6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758215718; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JDKbRh5hSHwbALeG12Liz7LnDWI0E7przxPdD0pxMAg=; b=Dlw5qVD6DlsoOShqqSbsTu3VXZOQz5BHsMNiKrWc4Jbm6FeR8dOchUoXDpAn5QaA9Yc9b7 xPZ+P6MREtWtFBvbHiOA0WXtI0KyfSsRnXkII6ufR6iBhpqkngR8PUa3jCLL2Mjc5VEbsX QqQEIv9MX/NUQ2m4CRWd1eOVmlPGNNY= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-588-wb4PAYZiPgKqr7-Dr6aS9g-1; Thu, 18 Sep 2025 13:15:16 -0400 X-MC-Unique: wb4PAYZiPgKqr7-Dr6aS9g-1 X-Mimecast-MFC-AGG-ID: wb4PAYZiPgKqr7-Dr6aS9g_1758215715 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9CF5A195605E for ; Thu, 18 Sep 2025 17:15:15 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.44.32.207]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C9E0030002C6 for ; Thu, 18 Sep 2025 17:15:14 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH mptcp-next v2 08/12] mptcp: cleanup fallback data fin reception Date: Thu, 18 Sep 2025 19:14:50 +0200 Message-ID: <2f7ce035835dfba0f4b03ea23be74a0bca760b8e.1758214564.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: nfP8sZlQs7IdXOQn-7-LE9_40tib43L6DgxvJJqTZdU_1758215715 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" MPTCP currently generate a dummy data_fin for fallback socket when the fallback subflow has completed data reception using the current ack_seq. We are going to introduce backlog usage for the msk soon, even for fallback sockets: the above condition will be not be correct as it will ignore data_seq sitting in the backlog. Instead generate the dummy data_fin when the last data packet is extracted by the fallback subflow. The scenario with fallback socket receiving a reset while the receive queue empty is caught via the generic 'all subflows closed' timeout: ensure such timeout is zero for fallback sockets. Signed-off-by: Paolo Abeni --- net/mptcp/ctrl.c | 2 ++ net/mptcp/subflow.c | 16 ++++++++-------- 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c index fed40dae5583a..4f7795968abe2 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -74,6 +74,8 @@ unsigned int mptcp_stale_loss_cnt(const struct net *net) =20 unsigned int mptcp_close_timeout(const struct sock *sk) { + if (__mptcp_check_fallback(mptcp_sk(sk))) + return 0; if (sock_flag(sk, SOCK_DEAD)) return TCP_TIMEWAIT_LEN; return mptcp_get_pernet(sock_net(sk))->close_timeout; diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index e8325890a3223..9baf3e54e46f2 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1297,14 +1297,6 @@ static void subflow_sched_work_if_closed(struct mptc= p_sock *msk, struct sock *ss =20 if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) mptcp_schedule_work(sk); - - /* when the fallback subflow closes the rx side, trigger a 'dummy' - * ingress data fin, so that the msk state will follow along - */ - if (__mptcp_check_fallback(msk) && subflow_is_done(ssk) && - msk->first =3D=3D ssk && - mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true)) - mptcp_schedule_work(sk); } =20 static bool mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk) @@ -1437,6 +1429,14 @@ static bool subflow_check_data_avail(struct sock *ss= k) subflow->map_data_len =3D skb->len; subflow->map_subflow_seq =3D tcp_sk(ssk)->copied_seq - subflow->ssn_offse= t; WRITE_ONCE(subflow->data_avail, true); + + /* last skb in closed fallback subflow: we are at data fin */ + if (subflow_is_done(ssk) && ssk =3D=3D msk->first && + skb =3D=3D skb_peek_tail(&ssk->sk_receive_queue)) { + mptcp_update_rcv_data_fin(msk, subflow->map_seq + + subflow->map_data_len, true); + subflow->map_data_fin =3D 1; + } return true; } =20 --=20 2.51.0