From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA06ACA9EAE for ; Tue, 29 Oct 2019 10:51:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BAF39205C9 for ; Tue, 29 Oct 2019 10:51:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=piap.pl header.i=@piap.pl header.b="KZ14oEaC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731008AbfJ2Kvn (ORCPT ); Tue, 29 Oct 2019 06:51:43 -0400 Received: from ni.piap.pl ([195.187.100.5]:47280 "EHLO ni.piap.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbfJ2Kvn (ORCPT ); Tue, 29 Oct 2019 06:51:43 -0400 Received: from t19.piap.pl (OSB1819.piap.pl [10.0.9.19]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ni.piap.pl (Postfix) with ESMTPSA id CA06E4435C4; Tue, 29 Oct 2019 11:51:40 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 ni.piap.pl CA06E4435C4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=piap.pl; s=mail; t=1572346301; bh=k5T289OuUG6VXWcIiryuoMqmX23h/XJduJPMuCqgoOg=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=KZ14oEaCQzQoroOWAQHrUaDc1v7cetvPs+6k+L+Z5bv3NE0kS334kY5zO01YjYgvf L+nOcLqWocanrPNwzJp2x8D4mHfWLJ/8AdV/n0P3U1Y7XPk0x+kUucW2E0jIgN4A8C llNJLqB9f4pJF1nEgII9vfQMtQo4a4Yl98Op4rP8= From: khalasa@piap.pl (Krzysztof =?utf-8?Q?Ha=C5=82asa?=) To: Johannes Berg Cc: "David S. Miller" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] 802.11n IBSS: wlan0 stops receiving packets due to aggregation after sender reboot References: <4725dcbd6297c74bf949671e7ad48eeeb0ceb0d0.camel@sipsolutions.net> Date: Tue, 29 Oct 2019 11:51:40 +0100 In-Reply-To: <4725dcbd6297c74bf949671e7ad48eeeb0ceb0d0.camel@sipsolutions.net> (Johannes Berg's message of "Tue, 29 Oct 2019 10:07:30 +0100") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-KLMS-Rule-ID: 4 X-KLMS-Message-Action: skipped X-KLMS-AntiSpam-Status: not scanned, whitelist X-KLMS-AntiPhishing: not scanned, whitelist X-KLMS-AntiVirus: Kaspersky Security 8.0 for Linux Mail Server, version 8.0.1.721, not scanned, whitelist Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Johannes Berg writes: >> The problem I can see is that the dialog_tokens are 8-bit, way too small >> to eliminate conflicts. > > Well, they're also per station, we could just randomize the start and > then we'd delete the old session and start a new one, on the receiver. > > So that would improve robustness somewhat (down to a 1/256 chance to hit > this problem). That was what I meant. Still, 1/256 seems hardly acceptable to me - unless there is some work around (a short timeout or something similar). Remember that when it doesn't work, it doesn't work - it won't recover until the sequence catches up, which may mean basically forever. Or, maybe the remote station can request de-aggregation first, so the subsequent aggregation request is always treated as new? Alternatively, perhaps the remote can signal that it's a new request and not merely an existing session? > That's the situation though - the local station needs to know that it > has in fact *not* seen the same instance of the station, but that the > station has reset and needs to be removed & re-added. Precisely. And it seems to me that the first time the local station learns of this is when a new, regular, non-aggregated packet arrives. Or, when a new aggregation request arrives. --=20 Krzysztof Halasa =C5=81UKASIEWICZ Research Network Industrial Research Institute for Automation and Measurements PIAP Al. Jerozolimskie 202, 02-486 Warsaw, Poland