From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [52.28.52.200]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 0B7053BA8E for ; Wed, 25 Apr 2018 12:17:36 -0400 (EDT) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1524673055; bh=5gscIjPja9T9/NVjXMvWXQ9Ui0v/wlbnT5fnXpFpUe0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=tX8llkPkvqeac6zZtGev+GF0zF/we5Uos576O09op4SBzrQlFy1UQRMInufdWtQe2 +gctOwt8qwrN+JwRGT6UMW60hjrPqhhCu96vhBbb3sIuFcXZ2VtI+e9avSkiYoZEgP 6xTaHx88mlG9ZODzg35uepH2KQfPW4IsHymK+YF9Iyq0O4iHi58poN5gLeVqXbnLtR GaEv8AL5Y39i3E+ww0EZx+0tYMWXcvsVDSvIj+eVv800EwRKd1tpLXxa5htpTNxDNO F2B6T17LTlWY67Qh0b+k540SRliiMIEw7UXFQYFPFsAl1HSgH3pqckfoJYXDFHuRnB zrvcNis2CVYrg== To: Eric Dumazet , netdev@vger.kernel.org Cc: cake@lists.bufferbloat.net, Dave Taht In-Reply-To: References: <20180425134249.21300-1-toke@toke.dk> <878t9b5n0q.fsf@toke.dk> Date: Wed, 25 Apr 2018 18:17:34 +0200 X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87zi1r5kgx.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] [PATCH net-next v3] Add Common Applications Kept Enhanced (cake) qdisc X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 Apr 2018 16:17:37 -0000 Eric Dumazet writes: > On 04/25/2018 08:22 AM, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> Eric Dumazet writes: > >>> Lack of any pskb_may_pull() is really concerning. >>=20 >> By this you mean "check that the packet is long enough to contain the >> header we are looking for before trying to do ACK filtering", right? > > > skb->len is not enough, you also have skb->data_len that matters. > > A qdisc can be fed with skbs that are not linear, or pretend to be > TCP, but they be truncated by malicious sender. > > skb might have headers or payload in the page fragments, thus we > generally have to call pskb_may_pull() to bring headers in skb->head Right, gotcha; was just making sure I understood you correctly. > Quite frankly , an ack-filter does not belong to a packet scheduler. > > It might be added to tcp conntrack module _if_ someone really cares. Well, integrating it with the queue does have the advantage of only filtering ACKs if the flow is actually bottlenecked... That being said, I'm not personally hugely attached to the ACK filter; let's see if someone one the cake list speaks up in favour of keeping it. Or am I to interpret that as a hard NAK on having this feature in CAKE (even if we fix the issues you pointed out)? -Toke