From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52C122D77E4; Wed, 2 Jul 2025 16:10:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751472657; cv=none; b=K4zMqc0w9UedoLS32rM9U6HIHxucMd9DR6X0f5Q9ZuPhWQUS2MUN6l60IxWvJRDPJeE5iYo6QwuyUYlQwdKKCvvltmibL6C1SJaX5Jr3UIlNcAVfKvD5cNB7NQrIdssuiDpRUVyvQRZ0QSAMsfPgu8+jR/G6fe7mARJdqvLFEGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751472657; c=relaxed/simple; bh=YdCT133p82j/BMPf6XPBFAhX9tGEdrgh/9PMIHJn8ng=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BMbfyvIWrhn8iNXf93N3oG5rKlbk/szivmXZnCxy/A9tqOa3bwfDzhdsVx1aOtyXxkG5v5MBdkBMQKM6+I8+fnRbcQxKho7QqsMGHiK/26Tk9vYWKckwyedWxNJlkCskFVE4f+dR8mZiGyngnNXOrltzh0UuUhn2hnvSfbOtRME= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L5xHOkLS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="L5xHOkLS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52CF3C4CEE7; Wed, 2 Jul 2025 16:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751472656; bh=YdCT133p82j/BMPf6XPBFAhX9tGEdrgh/9PMIHJn8ng=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=L5xHOkLSmVeNk2d9iOrtcD1bQ7piTvl8rrMPPnbXwbxYKPYxqrs0lDRYam3VHOIAd 6F6yxcsIgyRbzg50gzQk262bUjAcE/zPlrEFLDCSYE1Zx7icTC7y1vjIQ1vEoUCEkz Of/TgwJoFOr0N3984xFJDDFU34uPkGDzzuNUnbeEiz2crveRXtCLw24Ejl5cOpvCL4 Evb8HE14ncX4Scd5qeavGIWrkrc6Pg2DC2Zbn2IoIzVjwTIiUQrJFtruCsyJ3/Tytd 41CNdloAawF0jHMhdnZr2kA+JW6FS2QMkTiRzsQhmEUnSxL4tW2wUI9SOZa2dJWQml EamIJPunholxA== Date: Wed, 2 Jul 2025 09:10:55 -0700 From: Jakub Kicinski To: Nicolas Dichtel Cc: Gabriel Goller , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Jonathan Corbet , David Ahern , netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] ipv6: add `force_forwarding` sysctl to enable per-interface forwarding Message-ID: <20250702091055.3d70a5ee@kernel.org> In-Reply-To: <7c47cfb6-c1f1-42a1-8137-37f8f03fa970@6wind.com> References: <20250702074619.139031-1-g.goller@proxmox.com> <20250702073458.3294b431@kernel.org> <7c47cfb6-c1f1-42a1-8137-37f8f03fa970@6wind.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 2 Jul 2025 17:14:42 +0200 Nicolas Dichtel wrote: > > Should we invert the polarity? It appears that the condition below only > > let's this setting _disable_ forwarding. IMO calling it "force" suggests > > to the user that it will force it to be enabled. > Not sure to follow you. When force_forwarding is set to 1 the forwarding is > always enabled. > > sysctl | all.forwarding | iface.force_forwarding | packet processing from iface > | 0 | 0 | no forward > | 0 | 1 | forward > | 1 | 0 | forward > | 1 | 1 | forward Ugh, I can't read comparisons to zero. Let's switch to more sane logic: if (idev && !READ_ONCE(idev->cnf.force_forwarding) && !READ_ONCE(net->ipv6.devconf_all->forwarding))