From nobody Wed Sep 17 18:19:13 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 76ACF374279 for ; Tue, 16 Sep 2025 16:27:42 +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=1758040064; cv=none; b=PJCzD705rd9jHImzdqSJuhh45Q4A3DIOgSEH3iWCK06tJ0FCdDy+dbr34yHlE0xJNqYpeYfKi1sNxPa0H2TrcL2VNtL1RkHJOPPYiux+4rz5iiLZu6/xqZLjIvBzR54Zj9wn8fokooEMmpKvxtuDZnoFWLPDHGekppJtr8EEXN4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758040064; c=relaxed/simple; bh=BIJ8IVHYsAVzv8+xsF+ojFBqIaY5kmu6LjJkLZMWlvw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=NWYJDrew70KEkB4psNgKZGlT+VhizjB9ZIzJ2ksilsN0WqKNwFBgqzgcjFubGM0r8TKNGEiLwcRJ5yybPt5d1Si/8Qh/PkAFNkM8fRFJ1IYJA8urNFJ855EcPH+mggCOjbPIwdS4n6gwJ8h0aAj8dM6sNVDSvLca6z0HiTfKOdg= 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=DZ7G5r4U; 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="DZ7G5r4U" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758040061; 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=wDUcih6KYkyyo6nbKLPecOvpIZ7zrypSdMPS6+Z6AbU=; b=DZ7G5r4UVaYSIPlnVqdNOnyrs2+TvBkqEGh/n37AG47QDX525Ad9Uta2eu5io4x/ojIWu7 NkZzs8rh5GHuG1hF35hE7ptbYJRuoQI3Nd+kn41DJC2uv7+Rkwl8JevHLXgXqexXgpud5A h8tvKWxWVDLZWoJxG8LKw42yRUvelsg= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-414-xr8e80JUOjyIHYc4pGf_7g-1; Tue, 16 Sep 2025 12:27:40 -0400 X-MC-Unique: xr8e80JUOjyIHYc4pGf_7g-1 X-Mimecast-MFC-AGG-ID: xr8e80JUOjyIHYc4pGf_7g_1758040059 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 41D60180034D for ; Tue, 16 Sep 2025 16:27:39 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.44.32.160]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6BE2E19560B8 for ; Tue, 16 Sep 2025 16:27:38 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [MPTCP next 08/12] mptcp: cleanup fallback data fin reception Date: Tue, 16 Sep 2025 18:27:18 +0200 Message-ID: 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 3.0 on 10.30.177.12 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: b8UEdpYEDbHChGYHFiGeEEjZgeXwA-jX8_X6LwLxXcI_1758040059 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 catched 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 c8a7e4b59db11..5339a00528a7a 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1293,14 +1293,6 @@ 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) @@ -1433,6 +1425,14 @@ 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