From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-160.mta0.migadu.com [91.218.175.160]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E515F385D6E for ; Tue, 18 Aug 2026 09:14:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.160 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787044454; cv=none; b=tmYscqUBMsBWuEAe94HFbwrVUOdhZhbsxPJ8yBWZMXKsfZBmVsQdOg61YfKdX933ht1cDayvJnO8VX7op1QT4KrJwjX8Ke0ZyWzTZ8/X6h35wPnqNF+rQ0gJzuQeWbcEI1kCBe9wUs6nH/1smuvesHKpHhBthZS+/2cYopz7zvg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787044454; c=relaxed/simple; bh=cdIel/41jBffA38CiumFQd2Z1Q0V+nJxNt1aKYZNL40=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=J3QyG3kCvPR4XdTznGRwhpQdNLn+jpOBX55LIzitc31RbXPbpYO/AcIj5ep7KkUS7bUSljKDOw+oFL7tzMbzpJFuKEMtFA3Y1h7m8HsinlPpX5Pfkhlu0bhD0g0w/1PIVMWf+COr+5hicsS38VvwZ4EojQgB3vW/eH26wCGMGGo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=bS6hXj6P; arc=none smtp.client-ip=91.218.175.160 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="bS6hXj6P" X-Envelope-To: mptcp@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=cdIel/41jBffA38CiumFQd2Z1Q0V+nJxNt1aKYZNL40=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787044449; v=1; x=1787649249; b=bS6hXj6PVB4snPB9wFRpObBB5vtxBlG+pqHkDDcGGbSv4rNwplfXyUiIxiIIT4RhT1icviPe mOr5+MYO4d9TvHUaM7GN+q3w0baRFC2O2xnN3X89THfwT0ndcfBOi8H3okh7DEAc5W1t0EKgy8P aMhv8lesLfY1BmdnW0UqgoFE= X-Envelope-To: mptcp@lists.linux.dev Received: from localhost.localdomain (240a:4281:fe00:1ace:7fcd:c486:d361:c952) by smtp.migadu.com with ESMTPS id affab7ccf8cd6aa6; Tue, 18 Aug 2026 09:14:09 +0000 X-Migadu-Flow: FLOW_OUT From: Chenguang Zhao To: mptcp@lists.linux.dev Cc: chenguang.zhao@linux.dev, Chenguang Zhao Subject: [PATCH mptcp-next RFC v4 0/2] mptcp: fallback to TCP on MP_FAIL with a single subflow Date: Tue, 18 Aug 2026 17:14:15 +0800 Message-Id: <20260818091417.2200986-1-chenguang.zhao@linux.dev> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Chenguang Zhao As suggested by Paolo, on MP_FAIL reception bound the MP_FAIL reply and the infinite mapping in the same ACK. Patch1: Add MPFailFallback MIB. Patch2: Makes a pure ACK able to carry an infinite mapping: when send_infinite_map is set, mptcp_established_options_dss() fills a DSS map with data_len=0 even without a data skb. After the ACK that carries both the MP_FAIL reply and that mapping is sent, mptcp_try_fallback() is called immediately so the connection leaves MPTCP mode without waiting for a later data transmit. Chenguang Zhao (2): mptcp: add MPFailFallback MIB mptcp: send MP_FAIL and infinite mapping on the same ACK net/mptcp/mib.c | 1 + net/mptcp/mib.h | 1 + net/mptcp/options.c | 33 ++++++++++++++++++++++++++++++++- net/mptcp/pm.c | 5 +++++ net/mptcp/protocol.c | 8 +------- 5 files changed, 40 insertions(+), 8 deletions(-) -- v3: https://lore.kernel.org/all/20260812054653.43799-1-chenguang.zhao@linux.dev/ v2: https://lore.kernel.org/all/20260715061830.1057851-1-chenguang.zhao@linux.dev/ v1: https://lore.kernel.org/all/20260713064134.914507-1-chenguang.zhao@linux.dev/ -- 2.25.1