From patchwork Tue Jan 30 12:17:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 10191751 X-Patchwork-Delegate: johannes@sipsolutions.net Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C3E1960383 for ; Tue, 30 Jan 2018 12:17:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B2D9C2434C for ; Tue, 30 Jan 2018 12:17:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A69CE28949; Tue, 30 Jan 2018 12:17:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0A09C2434C for ; Tue, 30 Jan 2018 12:17:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751474AbeA3MRn (ORCPT ); Tue, 30 Jan 2018 07:17:43 -0500 Received: from s3.sipsolutions.net ([144.76.63.242]:34270 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751411AbeA3MRm (ORCPT ); Tue, 30 Jan 2018 07:17:42 -0500 Received: by sipsolutions.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_RC4) (envelope-from ) id 1egUr5-0008Os-IF; Tue, 30 Jan 2018 13:17:39 +0100 From: Johannes Berg To: linux-wireless@vger.kernel.org Cc: Matthias Schiffer , Johannes Berg Subject: [PATCH] cfg80211: use only 1Mbps for basic rates in mesh Date: Tue, 30 Jan 2018 13:17:38 +0100 Message-Id: <20180130121738.6299-1-johannes@sipsolutions.net> X-Mailer: git-send-email 2.15.1 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Johannes Berg Mesh used to use the mandatory rates as basic rates, but we got the calculation of mandatory rates wrong until some time ago. Fix this this broke interoperability with older versions since now more basic rates are required, and thus the MBSS isn't the same and the network stops working. Fix this by simply using only 1Mbps as the basic rate in 2.4GHz. Since the changed mandatory rates only affected 2.4GHz, this is all we need to make it work again. Reported-and-tested-by: Matthias Schiffer Fixes: 1bd773c077de ("wireless: set correct mandatory rate flags") Signed-off-by: Johannes Berg --- net/wireless/mesh.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c index 51aa55618ef7..b12da6ef3c12 100644 --- a/net/wireless/mesh.c +++ b/net/wireless/mesh.c @@ -170,9 +170,28 @@ int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev, enum nl80211_bss_scan_width scan_width; struct ieee80211_supported_band *sband = rdev->wiphy.bands[setup->chandef.chan->band]; - scan_width = cfg80211_chandef_to_scan_width(&setup->chandef); - setup->basic_rates = ieee80211_mandatory_rates(sband, - scan_width); + + if (setup->chandef.chan->band == NL80211_BAND_2GHZ) { + int i; + + /* + * Older versions selected the mandatory rates for + * 2.4 GHz as well, but were broken in that only + * 1 Mbps was regarded as a mandatory rate. Keep + * using just 1 Mbps as the default basic rate for + * mesh to be interoperable with older versions. + */ + for (i = 0; i < sband->n_bitrates; i++) { + if (sband->bitrates[i].bitrate == 10) { + setup->basic_rates = BIT(i); + break; + } + } + } else { + scan_width = cfg80211_chandef_to_scan_width(&setup->chandef); + setup->basic_rates = ieee80211_mandatory_rates(sband, + scan_width); + } } err = cfg80211_chandef_dfs_required(&rdev->wiphy,