From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail1.fiberby.net (mail1.fiberby.net [193.104.135.124]) (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 B91A23D093A; Mon, 31 Aug 2026 09:36:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.104.135.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788168981; cv=none; b=ucIExAdP0rXm9jOmrzYXWvcoBuMKRXCsUOnkEKQGD/0DZjqC0jtLv7E+EdRoQlrLHmC1eA0be2A9/c2KLfzMXOv7izlEcvQynZ+3Apxu6bSWjOpe2aLf2POsy/QFHjFmd/gC4Lo1lw4wUmlHE6oeIydT/IOAof1VD8crtVfplII= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788168981; c=relaxed/simple; bh=KO58p0Ae6Jri7xZx0xr2iF8axurkxY4+ZoZQSU/NPzo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hnajf3Pe2W8m782kTRDEsym1NUqvfdCG/ffhKF0TqHE0m4nFAznLgbnS5xWIJ9k9jcKtyJolSDGKFYmEI7NxRD+vl7r40M5m+kgWG+drLCWcg0VMuN2Tf7ySJ2n+r8f5RMs2ZgZWymo25VBixqF9lt9jjiB7bc3JvS6vlh7/KPQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fiberby.net; spf=pass smtp.mailfrom=fiberby.net; dkim=pass (2048-bit key) header.d=fiberby.net header.i=@fiberby.net header.b=dsghy3/R; arc=none smtp.client-ip=193.104.135.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fiberby.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fiberby.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fiberby.net header.i=@fiberby.net header.b="dsghy3/R" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=fiberby.net; s=202008; t=1788168970; bh=KO58p0Ae6Jri7xZx0xr2iF8axurkxY4+ZoZQSU/NPzo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dsghy3/RJiF7vSHxBwPW6bLKHnE5OzaCD1TQJ35xZmngyZdy8P93QxrPAP7+jBBvd tdTWHUUSZ0A2mYnn39hZt/UTt0n0b1mBsFgHguWfUoEENlRNAuY+h4r/o7UytQItkU Nzo6m7tMmoAhgWLnRnoABHr0ZhqDUr2306iA07csPP/J9gJMUWGIXKm8yRVIQ1nHEW v1H4YbbB32ePo5GImS/cuB5ZAnu1NdmA8YkRscY0Sk6XfozKmCef6LwVL8uCyfIek1 iAnFNEFfXod6lOE6r+uiNffyVeqjTlwWEcK682hz2ZEwOSkPkYBfKhn+tqrFao8U6d R3swD5i1zTzqQ== Received: from x201s (193-104-135-243.ip4.fiberby.net [193.104.135.243]) by mail1.fiberby.net (Postfix) with ESMTPSA id 0BFA9600FC; Mon, 31 Aug 2026 09:35:56 +0000 (UTC) Received: by x201s (Postfix, from userid 1000) id 32804201D69; Mon, 31 Aug 2026 09:35:24 +0000 (UTC) From: =?UTF-8?q?Asbj=C3=B8rn=20Sloth=20T=C3=B8nnesen?= To: Donald Hunter , Jakub Kicinski Cc: =?UTF-8?q?Asbj=C3=B8rn=20Sloth=20T=C3=B8nnesen?= , "David S . Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Felix Maurer , Danielle Ratson , Fernando Fernandez Mancera , Gabriel Goller , Patrick Rohr , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v2 1/3] netlink: specs: rt-link: update ipv6 devconf doc Date: Mon, 31 Aug 2026 09:34:53 +0000 Message-ID: <20260831093458.472180-2-ast@fiberby.net> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831093458.472180-1-ast@fiberby.net> References: <20260831093458.472180-1-ast@fiberby.net> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit devconf is even odder than described in commit 720447bd0b24 ("netlink: specs: rt-link: remove implicit structs from devconf"), where both IPv4 and IPv6 are described in an identical way: "u32 indexed by ipv?-devconf - 1 on output, on input it's a nest". There are two issues with that line for IPv6: 1) The subtraction is an IPv4 specific quirk, to avoid having an unused u32 at index 0, thus saving 4 bytes per net device being dumped: - In include/uapi/linux/ip.h the IPV4_DEVCONF_* enum begins with IPV4_DEVCONF_FORWARDING = 1, so the enum starts at 1, which is the reason for the subtraction in the IPv4 variant. - In include/uapi/linux/ipv6.h the DEVCONF_* enum begins with DEVCONF_FORWARDING = 0, so subtraction would underflow. - ipv6_store_devconf() in net/ipv6/addrconf.c also doesn't do the subtraction in the output path. 2) Setting IPv6 devconf through Netlink is not yet supported, as IFLA_INET6_CONF is not handled in inet6_set_link_af(). Reviewed-by: Fernando Fernandez Mancera Signed-off-by: Asbjørn Sloth Tønnesen --- Documentation/netlink/specs/rt-link.yaml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/netlink/specs/rt-link.yaml b/Documentation/netlink/specs/rt-link.yaml index b80c2ac3ac31..00c915031efd 100644 --- a/Documentation/netlink/specs/rt-link.yaml +++ b/Documentation/netlink/specs/rt-link.yaml @@ -2218,7 +2218,7 @@ attribute-sets: name: conf type: binary sub-type: u32 - doc: u32 indexed by ipv6-devconf - 1 on output, on input it's a nest + doc: u32 indexed by ipv6-devconf on output, input is not yet implemented - name: stats type: binary -- 2.55.0