From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (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 04C2B39D3EB for ; Tue, 18 Aug 2026 09:14:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787044472; cv=none; b=ETd8J0cofRDTHtkQ2hw0USU+p6VL3PDbFYIW5vKxuS0BW76luh352wu/2ZOPHCht4n1ukUt4V17Ww1iub2sJj2NqHa2ZQ7rcwehAwWtlvRttqfvVHETexCi9Q3GYxe5zyIltZ7f+fsIso76UQX60Qo9vExfzDEI7jcnPq2dTYRw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787044472; c=relaxed/simple; bh=MPmouoFMWLVmbLhDNE3+RuQC16P2tCoqBytFnr2sTxQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=E6lKzwplI/il3EGLmvtHu+rCXHegIq4Cd2KlA6AiUE+2dT3B4i7OVvhbYI4lPVoWkjJjuT3Yrp/z6a+EWZgnEpBmu7LXwPJQuf+OHzz0EE0FssUrsZ+mMglhW0LuO2B8C4CTxQc6lfURWQX/g8XWKJUsAFNagG0vip1/hXd1ffo= 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=N8Slf/0x; arc=none smtp.client-ip=91.218.175.170 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="N8Slf/0x" X-Envelope-To: mptcp@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=MPmouoFMWLVmbLhDNE3+RuQC16P2tCoqBytFnr2sTxQ=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787044468; v=1; x=1787649268; b=N8Slf/0xG2EpQW9xO48YMhsxpJf/FTQGqiARUnZ8KFAQ8wM2Znv3sP+AAA3u6YooRRYeLUtJ btjXoiP6R3ouBMWSV9elR0UbgUudw4jMx7CW8BASbVeTWCgonM5gKpi6Qun5NGLJF5CeoIRzIEW oUeY58vDMa/wmge94H4u8qqo= 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 3a08fa730a291e0e; Tue, 18 Aug 2026 09:14:28 +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 2/2] mptcp: send MP_FAIL and infinite mapping on the same ACK Date: Tue, 18 Aug 2026 17:14:17 +0800 Message-Id: <20260818091417.2200986-3-chenguang.zhao@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260818091417.2200986-1-chenguang.zhao@linux.dev> References: <20260818091417.2200986-1-chenguang.zhao@linux.dev> 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 On a single subflow, accepting MP_FAIL must leave MPTCP mode at once (RFC8684 ยง3.7). Emit the infinite mapping on the MP_FAIL reply ACK, then call mptcp_try_fallback() immediately after. Fixes: 1e39e5a32ad7 ("mptcp: infinite mapping sending") Signed-off-by: Chenguang Zhao --- net/mptcp/options.c | 33 ++++++++++++++++++++++++++++++++- net/mptcp/pm.c | 5 +++++ net/mptcp/protocol.c | 8 +------- 3 files changed, 38 insertions(+), 8 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 97da22668dbe..ecf77e77d2de 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -638,7 +638,29 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, opts->csum_reqd = READ_ONCE(msk->csum_enabled); mpext = skb ? mptcp_get_ext(skb) : NULL; - if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { + if (unlikely(subflow->send_infinite_map)) { + unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; + + if (opts->csum_reqd) + map_size += TCPOLEN_MPTCP_DSS_CHECKSUM; + + if (mpext) { + opts->ext_copy = *mpext; + opts->ext_copy.infinite_map = 1; + opts->ext_copy.data_len = 0; + } else { + opts->ext_copy.use_map = 1; + opts->ext_copy.dsn64 = 1; + opts->ext_copy.infinite_map = 1; + opts->ext_copy.data_len = 0; + opts->ext_copy.data_seq = READ_ONCE(msk->snd_nxt); + opts->ext_copy.subflow_seq = subflow->rel_write_seq; + } + + dss_size = map_size; + opts->suboptions = OPTION_MPTCP_DSS; + ret = true; + } else if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; if (mpext) { @@ -1566,6 +1588,15 @@ void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp, TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); } ptr += 1; + + if (unlikely(mpext->infinite_map)) { + subflow = mptcp_subflow_ctx(ssk); + if (subflow->send_infinite_map) { + subflow->send_infinite_map = 0; + MPTCP_INC_STATS(sock_net(ssk), + MPTCP_MIB_INFINITEMAPTX); + } + } } /* We might need to add MP_FAIL options in rare cases */ diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index ba7c6f80a183..69701ac7e436 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -895,6 +895,11 @@ void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq) pr_debug("MP_FAIL response received\n"); WRITE_ONCE(subflow->fail_tout, 0); } + + if (!mptcp_try_fallback(sk, MPTCP_MIB_MPFAILFALLBACK)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_FALLBACKFAILED); + mptcp_subflow_reset(sk); + } } static int mptcp_add_addr_len(int family, bool echo, bool port) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f879b1061f2d..abe45a31ca5f 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1417,13 +1417,7 @@ static void mptcp_update_infinite_map(struct mptcp_sock *msk, mpext->infinite_map = 1; mpext->data_len = 0; - - if (!mptcp_try_fallback(ssk, MPTCP_MIB_INFINITEMAPTX)) { - MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_FALLBACKFAILED); - mptcp_subflow_reset(ssk); - return; - } - + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); mptcp_subflow_ctx(ssk)->send_infinite_map = 0; } -- 2.25.1