From nobody Thu Nov 27 12:35:53 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 1904325BEE8 for ; Tue, 11 Nov 2025 07:24:15 +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=1762845858; cv=none; b=SxwDt+tEiulQ/87GoIhC2tL0rgs2HXurD2ljOgPq0Ovx0BAsvbLPgSDvljERLbl6yhlAqeB8izzJyTJZ6cZAKIvpiWFxFR37E+KELd3gVyf1dYa/O6TS9fGv4dAG9eWWx6wH48gFINtLW/6TQ171bAMebK2IVW7a7E1qtr6orRQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762845858; c=relaxed/simple; bh=5Xku2oeaDH2r+WnDYAKJU6Jx7K5XH81gDAEILr19Vzw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=QQjwkBjAesKCzznXxfnDXsxb+brSFWbwkeGG4triXBu3mZYRujUEJWVMwAj4fTWJJb+OprQyfd/mtVvKpNSvrDugZ28ZXnFySZpTDeMRy+Wh9RBgM3hCHTaEnvEiP2vnl2saCeoZ90CYfan3r8aekKMYkz2xTNKS4N+Slf7LFVg= 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=TH5SxfLo; 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="TH5SxfLo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762845854; 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=OlvhELsyR66yeRsiYUY3unVLrNM2XeS+HM1sD154JTU=; b=TH5SxfLod1ags0JiGZXFolnc76x9fzby2Ft0fuITT7mn6nkA0j2bR0Bu0gP+JsZnIWP0la cP7sbIkyNKEVhcKawBDMVaaXxNDKKsEF6hMjLnKMWSb9WHrD7YTfVnTyF1k8+OUDPm4IyH bQKya117F1oOB8a+8D3TeVjckVRdmwo= 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-376-KZDitfS_OrCJdDScgX1ovQ-1; Tue, 11 Nov 2025 02:24:13 -0500 X-MC-Unique: KZDitfS_OrCJdDScgX1ovQ-1 X-Mimecast-MFC-AGG-ID: KZDitfS_OrCJdDScgX1ovQ_1762845852 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 A5E241956063 for ; Tue, 11 Nov 2025 07:24:12 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.45.226.92]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B2719195608E for ; Tue, 11 Nov 2025 07:24:11 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH v2 mptcp-net 1/2] mptcp: do not fallback when OoO is present Date: Tue, 11 Nov 2025 08:24:05 +0100 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 10.30.177.17 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: hQ4Ve4wBMJYzYWGNyp6DktSdX19HZDfSFnCJGNwo-co_1762845852 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" In case of DSS corruption, the MPTCP protocol tries to avoid the subflow reset if fallback is possible. Such corruptions happen in the receive path; to ensure fallback is possible the stack additionally need to check for OoO data, otherwise the fallback will break the data stream. Fixes: e32d262c89e2 ("mptcp: handle consistently DSS corruption") Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/598 Signed-off-by: Paolo Abeni --- Note: this does not avoid the WARN(), but fixes the inconsistend read() behavior; the ingress data is OoO, we should not ack it --- net/mptcp/protocol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index d6b08e1de358..7b966f105f89 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -646,7 +646,8 @@ static void mptcp_check_data_fin(struct sock *sk) =20 static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk) { - if (!mptcp_try_fallback(ssk, MPTCP_MIB_DSSCORRUPTIONFALLBACK)) { + if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || + !mptcp_try_fallback(ssk, MPTCP_MIB_DSSCORRUPTIONFALLBACK)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSCORRUPTIONRESET); mptcp_subflow_reset(ssk); } --=20 2.51.1 From nobody Thu Nov 27 12:35:53 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 9BD0A2459EA for ; Tue, 11 Nov 2025 07:24:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762845859; cv=none; b=UFzwpdpDGyGw6Fzd5mKv4B5Bk27xFDpEIVu+ZTQDeYpn/9jqBIhoixwOOvHiUobJ4G/1niRRueDy7XOnJ7+5DvBeYtdUqQF9q9yBc8DuT7HC5ZA8mo8KTiAx1ANfDOd3S/C5/Fua8Je+iNpinbwYWyKxzahZpXGwJfPHpv6tm6I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762845859; c=relaxed/simple; bh=sEdmj8Lj1mgXrPKA+9Yu54ma4hFS2QbS65spjcksIPk=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=Kiytr58+TIV6nM8vNS/Yk+36IsqcS1SJeujiK+VgNkk+Yofwr14C3KEisHT1a7HoYJ8LoBxp/bjIMHNnR9OeXz+f2qwr0+E9MYvITbZjBm0Je2++4+5ccPR2U8qBrUB9DfDyXImhw273TUA8jSe6GnaFY5lAqwWrOel4qQ4kk+c= 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=PAK+sJVY; arc=none smtp.client-ip=170.10.129.124 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="PAK+sJVY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762845856; 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=V/BGcv991J+xA3PFXi+73VQusjZjSrBjXTe19NuSE8w=; b=PAK+sJVYKTzXU4Wqr+0kyJo0JszQVuWP4grhLfChEkzvIPTax5wLe74b0mvsmJMbwIrqVR arb+ND2Y2/dMhOGl3I6s34tKpX2z9BDcbGcCyAUYXD8ZTFRbd8rzBt0i05mLyqO2VXsEZq Q+YmD+RLHu72jVMoTAm40gqWpmp5aek= 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-527-3yR_-TI7Pam5mtqoAADyzA-1; Tue, 11 Nov 2025 02:24:14 -0500 X-MC-Unique: 3yR_-TI7Pam5mtqoAADyzA-1 X-Mimecast-MFC-AGG-ID: 3yR_-TI7Pam5mtqoAADyzA_1762845854 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 07F17195605C for ; Tue, 11 Nov 2025 07:24:14 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.45.226.92]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 137B6195608E for ; Tue, 11 Nov 2025 07:24:12 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH v2 mptcp-net 2/2] mptcp: do not drop partial packets. Date: Tue, 11 Nov 2025 08:24:06 +0100 Message-ID: <5fe0aeae7501fc5837847a9e13ad883a8f039e64.1762845791.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 3.0 on 10.30.177.17 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: aGR3LjVE9vMQ2rngWduET-WEfPKs50DeSU54_U1r7yc_1762845854 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" Currently MPTCP drops partial packets for no good reason at all. Instead we should just skip the already acked bytes. Also add a missing check for zero window, which in turn requires properly initializing the rcv_wnd_sent at connection creation time. Fixes: ab174ad8ef76 ("mptcp: move ooo skbs into msk out of order queue.") Signed-off-by: Paolo Abeni --- Notes: - We should also add a MIB for zerowin drop, but that should be a follow-up patch, I think. - based on top of 'mptcp: autotune related improvement', but targeting net, will have a conflict in __mptcp_move_skb(). --- net/mptcp/protocol.c | 27 ++++++++++++++++++++------- net/mptcp/subflow.c | 3 ++- 2 files changed, 22 insertions(+), 8 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 7b966f105f89..e3330141a6da 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -378,6 +378,10 @@ static bool __mptcp_move_skb(struct sock *sk, struct s= k_buff *skb) =20 mptcp_borrow_fwdmem(sk, skb); =20 + /* Check for zero window.*/ + if (atomic64_read(&msk->rcv_wnd_sent) =3D=3D msk->ack_seq) + goto drop; + if (MPTCP_SKB_CB(skb)->map_seq =3D=3D msk->ack_seq) { /* in sequence */ msk->bytes_received +=3D copy_len; @@ -386,18 +390,27 @@ static bool __mptcp_move_skb(struct sock *sk, struct = sk_buff *skb) if (tail && mptcp_try_coalesce(sk, tail, skb)) return true; =20 - skb_set_owner_r(skb, sk); - __skb_queue_tail(&sk->sk_receive_queue, skb); - return true; + goto enqueue; } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { mptcp_data_queue_ofo(msk, skb); return false; } =20 - /* old data, keep it simple and drop the whole pkt, sender - * will retransmit as needed, if needed. - */ - MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + /* Check for old data. */ + if (!after64(MPTCP_SKB_CB(skb)->end_seq, msk->ack_seq)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + goto drop; + } + + /* Partial packet, seq < rcv_next < end_seq. */ + MPTCP_SKB_CB(skb)->offset +=3D msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; + +enqueue: + skb_set_owner_r(skb, sk); + __skb_queue_tail(&sk->sk_receive_queue, skb); + return true; + +drop: mptcp_drop(sk, skb); return false; } diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 39bf69e73975..0db832b5ddca 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -496,7 +496,8 @@ static void subflow_set_remote_key(struct mptcp_sock *m= sk, WRITE_ONCE(msk->remote_key, subflow->remote_key); WRITE_ONCE(msk->ack_seq, subflow->iasn); WRITE_ONCE(msk->can_ack, true); - atomic64_set(&msk->rcv_wnd_sent, subflow->iasn); + atomic64_set(&msk->rcv_wnd_sent, subflow->iasn + + tcp_receive_window(tcp_sk(subflow->tcp_sock))); } =20 static void mptcp_propagate_state(struct sock *sk, struct sock *ssk, --=20 2.51.1