From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: mail.toke.dk; spf=pass smtp.mailfrom=; dkim=pass header.d=mattcorallo.com; arc=none (Message is not ARC signed); dmarc=pass (Used From Domain Record) header.from=mattcorallo.com policy.dmarc=reject Received: from mail.as397444.net (mail.as397444.net [IPv6:2620:6e:a000:1::99]) by mail.toke.dk (Postfix) with ESMTPS id D035162C2C6 for ; Sun, 07 Sep 2025 14:40:07 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mattcorallo.com; s=1757247662; h=Subject:From:To:From:Subject:To:Cc:Cc: Reply-To:In-Reply-To:References; bh=5hT8GjcENoaE84O5rDL9BxhtSzuk0NRjDrARedx3brg=; b=ZI8OzX9sgTyh/Wa+BxtnYpBRnP SJDmv91BcCYxTbxSbioq8Vj0X3sIJ3xaKfWYYYtzcuA3/DxBvTBe6OBXAqhZsvHreSl3z1psuZFfN 5TDINLPXUfVQRVYN8XyajT5CFszqiCmL747zT1msg6Fk0ojWXHad2SbCbWe2fklNsqMh6eDo3Yjtw q5REhJyYU3wAQAZ3ZhfvguFz+Q5vQqZqggfZivhrPXwEA4e2qOwD/BZY2/y4kgc7J5KEQz2ZYKxDI 7AN1BCvXFByeIrh4Q2kizFj55gqAYtMhP69vqry8qL2FpAz29CSk/y1rKuG7QmQ0ceewGCyGIzI5/ 0OTHlUDA==; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=clients.mail.as397444.net; s=1757247664; h=Subject:From:To:From:Subject:To: Cc:Cc:Reply-To:In-Reply-To:References; bh=5hT8GjcENoaE84O5rDL9BxhtSzuk0NRjDrARedx3brg=; b=AuhYx7am7zDrYq6FxU7q9CCQts XhVdg0mD7TVSuzvgEElQ/oeH6iElL0gbhGj5IaDcC+jwF6rWce0epzWad5NmLkN+s7enDJRJXlnPB y3yHH6OoEr50R5sh6hUaFSJZBB9GFyG9dam4ImeyouQ1J5lMIy2nNrrY4Jarjdp1jL2n5WRNuarve qk45bsn8HWWarn0AImXd0fCWWeEZ0/WVeS7+GuZ7SK3ublAKuApuYzbEhb5ey2JDe98cKO76Z/H0v QmPDuPN45Rzj2iTpGLWAMMiSAHdpduqZfdCGC3aCQbfSnKzTbHorM8AHoPyFgl3NcoSqLrPWBjLu+ zgxwIA9w==; X-DKIM-Note: Keys used to sign are likely public at X-DKIM-Note: https://as397444.net/dkim/mattcorallo.com and X-DKIM-Note: https://as397444.net/dkim/clients.mail.as397444.net X-DKIM-Note: For more info, see https://as397444.net/dkim/ Received: by mail.as397444.net with esmtpsa (TLS1.3) (Exim) (envelope-from ) id 1uvEgg-00000001hhd-0Va4 for cake@lists.bufferbloat.net; Sun, 07 Sep 2025 12:40:06 +0000 Message-ID: <78318be7-30d0-4f6a-80f3-063f4558b142@mattcorallo.com> Date: Sun, 7 Sep 2025 08:40:05 -0400 MIME-Version: 1.0 To: cake@lists.bufferbloat.net Content-Language: en-US From: Matt Corallo Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Message-ID-Hash: DEURWBG6ZJJROGNDWMSBH2KUHADV7CL7 X-Message-ID-Hash: DEURWBG6ZJJROGNDWMSBH2KUHADV7CL7 X-MailFrom: cltaapptfwbs@mattcorallo.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list Subject: [Cake] Parsing DSCP out of skb->priority List-Id: Cake - FQ_codel the next generation Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Its (presumably) not uncommon to have multiple encapsulation tunnels running on a host which then wants to do (cake) shaping on the actual outbound interface. In this case, the skb->hash is (hopefully) preserved from the original packet to select the right flow queue, but the DSCP isn't. This is ideally what the priority field of the skb is for - `skbedit` can set the priority flag of the packet before "exiting" the tunnel interface, and cake can ultimately read that priority flag to select a tin. However, doing so requires manual tin mapping in skbedit, reading the DSCP field and mapping them to the right tin entirely be hand. skbedit also supports `inheritdsfield` which just sets skb->priority to the DSCP field as-is. It would be nice if cake could read such priority fields, treating skb->priority as a DSCP when TC_H_MAJ(skb->priority) is zero (which it always will be in this case). Is there any interest in a patch to do so? Would such a patch need a new userspace option to disable it, or would wash suffice?