From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793709846; b=yUGtKr/e5cx2gazOpXsWFHn/AqL8IJqvcTSXMxmR6EduNcFmrGkQg2Oxw5XSWNa0JxSR kGwDGAOo62PcNXzxyxqMaFTRbX2YJuJzJAggIONcXVHLIGvLZdcWmtq6rJmskzhZ+7GAs f0LUWNEsR9fNnLEMYRQKWeeU8PhYTqZNRMqHSnCpcBG/kkzUAsuQ4gxGOJCcX6wEgh6OB MOUNlbONUTmRkQMDVswXpW2wKvUCBHGWQFgDhCvOP/JNHMWrkV2+qPk5h6KiHIrXWactt RKuUSlLIQXmqHTae5MAc09dJ4kOuVN3wce/VdTgVjQBNLjtFEgwHSo7G2tsSnSBWuZQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793709846; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=lpn/R1aA8HbvXNstFgjD6czhaiXvrQxTqDM1qfiPs2A=; b=MdTYpIxsonTcQ5UCsKSZDyZP7o41D0uzsOGKn9iQEUGyq7F72Qxcjiok8Ruq2oa5gByf YVuJ/aDUArvSQEbbCn7I5HF/e5xQBkeNuJFMwJL6nM66yafADLyXpH4EQyNKBM38j2qsj XMCA31SG2X+WCUf63Y1IWTqRtp0Kdm8YcpWZXUdd93DpZl6/JDAN4rJo5eh+7sJdsQffe Cufm+oDi7zYtlZoZd/Aw6fDZkZEOUjJFmUJsmSxD6OzK4UTJyhE4kBnM9HOmkGkpEsk6j xCvEqXuMoNTTwmjxiOk3lFfimMNM7GyFF0PZxD9OwEwPpbTHuTJkYdrfPM43D1+bQog== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Vs1HNlQv; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B6893606D827; Tue, 3 Nov 2026 12:44:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Vs1HNlQv Received: by smtp.kernel.org (Postfix) with ESMTPSA id 833C01F00A1F; Tue, 3 Nov 2026 12:44:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793709845; bh=lpn/R1aA8HbvXNstFgjD6czhaiXvrQxTqDM1qfiPs2A=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Vs1HNlQv6Lvx4JAage7a7MTsuDjgmPpu/IRARR9pWT086+jouhGDlqWB+rUFjtCBf 0QxnO1rn6Z5DLQvQv7wUJ+xc6xpJ2JguJMGSvixdayN5NFT6vNtZ5CgMkPr1+k/ti3 nXpswpwt5WBYPGkUOuQXS/Dkmp3/DsVP3/plpA1A96BuKCkHecy100rAIJyJyhzAgD IJLQ4UjqdZowQpzf+1xAztAbAB+Hl+H+PFsaWx2XhYRkzWIHc+CGEMYabs3HQ2AOSG ZHKWC2XhaRAb9ol1FLy2GX8oPXXNt8GaEGiE5ExkO+FdU8PLMCFlMxU7T+fitDEb7W tWTvcXKPKVvIw== Date: Tue, 3 Nov 2026 12:44:00 +0000 From: Simon Horman To: Julius Bairaktaris Cc: netdev@vger.kernel.org, dsahern@kernel.org, idosch@nvidia.com, davem@davemloft.net, edumazet@kernel.org, kuba@kernel.org, pabeni@redhat.com, steffen.klassert@secunet.com, willemb@google.com, jiayuan.chen@linux.dev, mfleming@cloudflare.com, almasrymina@google.com, bigeasy@linutronix.de, richardbgobert@gmail.com, ecree.xilinx@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH net v4 2/4] net: gso: count the inner UDP header of encapsulated UDP GSO packets Message-ID: <20261103124400.GK865646@horms.kernel.org> References: <7b6a12fbe0853f7faf2987610e25957d2017bd54.1792838740.git.julius@bairaktaris.de> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7b6a12fbe0853f7faf2987610e25957d2017bd54.1792838740.git.julius@bairaktaris.de> On Sun, Nov 01, 2026 at 05:42:30PM +0100, Julius Bairaktaris wrote: > skb_gso_transport_seglen() adds the inner TCP header length for an > encapsulated GSO packet, but not the inner UDP header for > SKB_GSO_UDP_L4, whose gso_size covers the payload only. Every segment > of a UDP GSO packet in a UDP tunnel, built by UDP GRO behind a tunnel > socket or sent with UDP_SEGMENT over VXLAN, is counted 8 bytes short. > ip_forward() and ip_finish_output_gso() then let DF segments that > exceed the MTU by up to 8 bytes leave unfragmented. > > Add the inner UDP header as the unencapsulated branch does. > > Fixes: ee80d1ebe5ba ("udp: add udp gso") > Signed-off-by: Julius Bairaktaris Reviewed-by: Simon Horman