From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-139.mta1.migadu.com [95.215.58.139]) (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 87F3D381AE4 for ; Wed, 19 Aug 2026 11:21:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.139 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787138467; cv=none; b=VyhCU0FEkrQ6mn/vKvwvl7mUHqveMiYFavYINmvxK48X/ZWqk4iwS+K4dmvkAz5nz8A7C8IC+QUcA1msq/bhBEcicYfyS4s3BMi04KrX0ECGlahjbOlQ+7midB1fYxHCO6vdVt5N7apcc0oV34puyEfjyuamjbL42l4n+1nlbM4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787138467; c=relaxed/simple; bh=K9SYtSYrcUUzhStkIn9dcSaf8Rrq6ewmhBK2ChNSrnM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=pZcXynK7wLz92oq742a7oNnOsJ08B8zcr8c4A0ExAIxp7rJ46EOJm8G2lA0cTAV399wHadbEMqHctuGWmjKOEcmGYb/tBLEPWKFNdl3bDGCHaNmV+K8CE5QN2eJTrVuE2DfI5uf5fXlqrorfRZeLU/WNMZPc9FBVYPs8dH29oMc= 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=Qyk9a658; arc=none smtp.client-ip=95.215.58.139 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="Qyk9a658" X-Envelope-To: mptcp@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=K9SYtSYrcUUzhStkIn9dcSaf8Rrq6ewmhBK2ChNSrnM=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787138461; v=1; x=1787743261; b=Qyk9a658o8nmdUb1Xn7ezym8LTW5Pi4QlIdV8B16bEwKLLl89MZb22sQin6Pyinmi9m6n3GA Logma+0RODO8X2MW0hoiz8xikVyMi4uTdzSPxu6i1CbSuppvC2oBS0TuniaBPAvms+4lNufzdWS XbMvDtPrYiZmiqZ3afXoccrA= X-Envelope-To: mptcp@lists.linux.dev Received: from localhost.localdomain (223.70.159.239) by smtp.migadu.com with ESMTPS id ff202aea241f8031; Wed, 19 Aug 2026 11:21:01 +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 v5 0/3] mptcp: fallback to TCP on MP_FAIL with a single subflow Date: Wed, 19 Aug 2026 19:21:09 +0800 Message-Id: <20260819112112.1985121-1-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-Transfer-Encoding: 8bit From: Chenguang Zhao Patch1: Add MPFailFallback MIB counter Patch2: Move the FALLBACK_DONE flag setting to right after MP_FAIL is received. Patch3: Add a __mptcp_check_fallback() check inside mptcp_can_accept_new_subflow() to reject MP_JOIN requests earlier. I have tested with the script from the linked URL, and the kernel is now able to reject MP_JOIN requests early. https://github.com/chrisocean716-star/packetdrill/blob/fed57fab92c407eb433acdb8c8ce72bd8e3e2f37/gtests/net/mptcp/mp_join/mp_join_server_after_fallback.pkt Chenguang Zhao (3): mptcp: add MPFailFallback MIB counter mptcp: fallback immediately on MP_FAIL reception mptcp: reject new subflows after fallback net/mptcp/mib.c | 1 + net/mptcp/mib.h | 1 + net/mptcp/pm.c | 5 +++++ net/mptcp/protocol.c | 8 +------- net/mptcp/subflow.c | 1 + 5 files changed, 9 insertions(+), 7 deletions(-) v4: https://lore.kernel.org/all/20260818091417.2200986-1-chenguang.zhao@linux.dev/ 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