From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f41.google.com (mail-ej1-f41.google.com [209.85.218.41]) (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 B30863DDB1C for ; Thu, 10 Sep 2026 09:00:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789030866; cv=none; b=WZ4ydlzA/Nt56NGacsWbc2ZaPMTvzubWBKbKb5o9/wPtvvVEmoXZ9ootOOCj3CBvgPpS32RPjQXGsj/KRrQjd/UYMn7zWrnnEE5olUaBPpmcIfq/7DVFWg20hsn/t4fRCvQDuYlJxb/xvv1z1TkdU+67ONREpIG2DEfBGwGRuKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789030866; c=relaxed/simple; bh=tYhCwCWxuhguq6pfAupubVPjCxdBVlF4RC/Qb+PCngw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mg1qjHzW2frvlh/JS9vNv20OcxX6arj0kgaHL+rtJ5Y23sDc8j2EdTacS1uaUk+nU/xQB3mHxhHkh9pdG9RWynC/iU0lbCbsBenJVynlMePYxWJhVv3cEE9G07TIL1DOPRiwbNgtgdoeBWUckrY5pL+UPeJjYAwFR5Fi9mJqPpA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bairaktaris.de; spf=pass smtp.mailfrom=bairaktaris.de; dkim=pass (2048-bit key) header.d=bairaktaris.de header.i=@bairaktaris.de header.b=N1xfBMQp; arc=none smtp.client-ip=209.85.218.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bairaktaris.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bairaktaris.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bairaktaris.de header.i=@bairaktaris.de header.b="N1xfBMQp" Received: by mail-ej1-f41.google.com with SMTP id a640c23a62f3a-c250a2bc3b3so854032466b.2 for ; Thu, 10 Sep 2026 02:00:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bairaktaris.de; s=google; t=1789030854; x=1789635654; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=znPVXyZXPnFTO1sJfrnUQLvHd7wsibn1+GKNiaFiRTA=; b=N1xfBMQpU9V0Gdm/PhYI6O8emI+YJt5rZG+nYrxO0tu+E7et4PV9qBZJ0AvB3aNNAk PPLqDG5oUyBUugTFoxEFA0Fb/uxu0QEJMNx01IOmNh9aDozViYtt5S4/SYwmWDVPDRiG qwuF6ff2NZfLuPWnrwfE3cExCxFqxVSerNwiatG0sar9Cxa39FSUWGGYYD8yPI59MBDw HS/kXPB/Cjb4AK62Acaa6PwiU9Pq+ojDJq7jKdaKD9bEkJfuH9idzfV+U0Jo1jo+dBmV MKY+ti5wUyF2TmIbmTeXSCbds3c18RWrHbb1wN4B7ZpTZ7ybSmWifXoZ8zlKBi9Ci7wg lqVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789030854; x=1789635654; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=znPVXyZXPnFTO1sJfrnUQLvHd7wsibn1+GKNiaFiRTA=; b=rB5hLB/d0fa+FN9/7xv4jI+bv044kByDGAHbiFHx1JP6Tf2AwmOvO5ik7SlOc7rNHr JQ+xNI88YbfJIQl72SyAmMUPqxc9AO8F4uOAzSeNmiDWxpE68OS0GomhV3SlbwLCLGJ+ BEO3UD1Ie/jNfTmq5F0zo9oGfRr3PZWdvs4A8YP2hJHWDKlMw+CjfKGMpUCw5a8XfbkH kWKDEflJsCcij5sMwgHU4IBft3seqmDBLQuVzORCtynRm1Qheue2CPf0D2/n3rC/sBN+ BqVDKsgKbxfemuRQcEZEsehzm9kKf7Do4wyNLyc3wIc9sksUg6c9TBhR+c9NJWkP3R5w PfDw== X-Forwarded-Encrypted: i=1; AKwUvBwA6ijtQu3rVgUDGR9wjvjYYSvU0d5/EabI7sdOayEtyIrGH5xF0AnLL2uBW86YPI7nEqVlcRs=@vger.kernel.org X-Gm-Message-State: AFuF++l5VrqXUjHr4fxxHCkQOg98X+eIcMs7ubs+K2BGEEnZNVrXVSd3 GJBEJt4UjDM1dR9q+IKUBzpl49yaYVeqylxkA+e5k9Vi8jWVmlfrOh8r0CWMhZOeYKPpr4p4aqZ ttZAcXaZmolRsUg== X-Gm-Gg: AYBFou2ZqX5Qb+ShOE4mTHRyxtlxrVHboEDk6oz88MjjbggFqEiBVD2X8cURCjYfM+v JxvEfQ8LR3NTCh47GnyJxBX2KNNYWOCjbUvgkTWHc0i1pFjZbaFstVNb1qjg2KnmREMgL86JxVm KdgSXF6DY5vgZiZV3bbjhm69/LISMqfY1h8QjI1xSHeZ1DlTklL9Q0cUvlM0uR2ZQdMzABUULXB Z9T5KKY54YX4x7y/sjPNuTJwklzIiXpDLry4JX61b3ANb5Sutzofv9wZxZ5ER/yFnINF0Ai5duu jSCor78wB1HESaP4SRF9WtXCqwSbDF1kOFh+xi17fWSStpRJkPzJV+w7sEEeZLHxUd0Lm3iSN2i zmG3AwJoXlhTwIo1RklQjIMsOI1J3OsXYt4V+v3cJ3aTX3pdCdCsl/KksUxQggvcqxrWQ05DrGJ yhh/KFChCpYFZ5oY7xVOVrIQO4g9alrJJEEGzskZVsJsx+Vk1R5Aii+4iAVB1oyCMXmidTr3YQj B/u25vPTcdUtZBW+T4/OcUWL9jb5wehRcpa1Vxz6tfQt7i4HW4sPrEfRLjorWEtYNEWgxAMEX1t jIm/amBXhAzsZzQA5sYHGheelRU5IkRLtXZS/6xz6jRTlID5QwHtMwIQFPmcR4QW4Soun4z0NAu 0qXRGm8XS3NN5cl1oxEYk2WHceOeVJjmyXHAi16+b7BvqXeI9rvDrpdj7RoFwikK0+4ejOgVQ/5 KmSYlgkQ== X-Received: by 2002:a17:906:8d89:b0:c24:c250:a6b5 with SMTP id a640c23a62f3a-c260c993a9amr1596510266b.12.1789030854121; Thu, 10 Sep 2026 02:00:54 -0700 (PDT) Received: from Desktop.fritz.box ([217.26.235.87]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c293eaf1ae8sm156106766b.40.2026.09.10.02.00.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2026 02:00:53 -0700 (PDT) From: Julius Bairaktaris To: pablo@netfilter.org, netfilter-devel@vger.kernel.org Cc: kadlec@netfilter.org, fw@strlen.de, coreteam@netfilter.org, netdev@vger.kernel.org, geldot@protonmail.com Subject: [PATCH nf-next 2/4] netfilter: flowtable: promote a flow offloaded in one direction only Date: Thu, 10 Sep 2026 11:00:50 +0200 Message-ID: <20260910090052.2034970-3-julius@bairaktaris.de> In-Reply-To: <20260910090052.2034970-1-julius@bairaktaris.de> References: <20260910090052.2034970-1-julius@bairaktaris.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A flow offloaded in the original direction alone carries a reply tuple that conntrack has never seen a packet for. Leave that direction on the classic path, so conntrack tracks it, and offload it as well once the connection is assured. act_ct promotes its unidirectional UDP flows on the same condition. Signed-off-by: Julius Bairaktaris Assisted-by: Claude:claude-opus-5 --- net/netfilter/nf_flow_table_ip.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index c8c29a9a1684..f2cd5c2c5365 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -465,6 +465,26 @@ nf_flow_offload_lookup(struct nf_flowtable_ctx *ctx, return flow_offload_lookup(flow_table, &tuple); } +/* The reply direction of a flow offloaded in one direction only stays on the + * classic path so that conntrack sees it. Once conntrack has, the flow is + * offloaded in both directions. + */ +static bool nf_flow_reply_unoffloaded(struct nf_flowtable *flow_table, + struct flow_offload *flow, + enum flow_offload_tuple_dir dir) +{ + if (dir != FLOW_OFFLOAD_DIR_REPLY || + test_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags)) + return false; + + if (test_bit(IPS_ASSURED_BIT, &flow->ct->status)) { + set_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags); + flow_offload_refresh(flow_table, flow, true); + } + + return true; +} + static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx, struct nf_flowtable *flow_table, struct flow_offload_tuple_rhash *tuplehash, @@ -478,6 +498,9 @@ static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx, dir = tuplehash->tuple.dir; flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]); + if (nf_flow_reply_unoffloaded(flow_table, flow, dir)) + return 0; + mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset; if (flow->tuplehash[!dir].tuple.tun_num) mtu -= sizeof(*iph); @@ -1074,6 +1097,9 @@ static int nf_flow_offload_ipv6_forward(struct nf_flowtable_ctx *ctx, dir = tuplehash->tuple.dir; flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]); + if (nf_flow_reply_unoffloaded(flow_table, flow, dir)) + return 0; + mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset; if (flow->tuplehash[!dir].tuple.tun_num) mtu -= sizeof(*ip6h); -- 2.53.0