Return-path: Received: from mail-lf0-f48.google.com ([209.85.215.48]:33630 "EHLO mail-lf0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956AbeB0KOa (ORCPT ); Tue, 27 Feb 2018 05:14:30 -0500 Subject: Re: Problem with bridge (mcast-to-ucast + hairpin) and Broadcom's 802.11f in their FullMAC fw To: =?UTF-8?Q?Linus_L=c3=bcssing?= , Felix Fietkau , Arend van Spriel , Franky Lin , Hante Meuleman , Chi-Hsien Lin , Wright Feng , Pieter-Paul Giesberts References: Cc: Network Development , bridge@lists.linux-foundation.org, "linux-wireless@vger.kernel.org" , "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" , brcm80211-dev-list@cypress.com From: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= Message-ID: <88d080df-4cce-98d1-6482-0408a3dcb015@gmail.com> (sfid-20180227_111438_676335_0C24F3A8) Date: Tue, 27 Feb 2018 11:14:26 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Sending with a fixed linux-wireless ML address. Please kindly send your replies using linux-wireless@ On 02/27/2018 11:08 AM, Rafał Miłecki wrote: > I've problem when using OpenWrt/LEDE on a home router with Broadcom's > FullMAC WiFi chipset. > > > First of all OpenWrt/LEDE uses bridge interface for LAN network with: > 1) IFLA_BRPORT_MCAST_TO_UCAST > 2) Clients isolation in hostapd > 3) Hairpin mode enabled > > For more details please see Linus's patch description: > https://patchwork.kernel.org/patch/9530669/ > and maybe hairpin mode patch: > https://lwn.net/Articles/347344/ > > Short version: in that setup packets received from a bridged wireless > interface can be handled back to it for transmission. > > > Now, Broadcom's firmware for their FullMAC chipsets in AP mode > supports an obsoleted 802.11f AKA IAPP standard. It's a roaming > standard that was replaced by 802.11r. > > Whenever a new station associates, firmware generates a packet like: > ff ff ff ff ff ff ec 10 7b 5f ?? ?? 00 06 00 01 af 81 01 00 > (just masked 2 bytes of my MAC) > > For mode details you can see discussion in my brcmfmac patch thread: > https://patchwork.kernel.org/patch/10191451/ > > > The problem is that bridge (in setup as above) handles such a packet > back to the device. > > That makes Broadcom's FullMAC firmware believe that a given station > just connected to another AP in a network (which doesn't even exist). > As a result firmware immediately disassociates that station. It's > simply impossible to connect to the router. Every association is > followed by immediate disassociation. > > > Can you see any solution for this problem? Is that an option to stop > multicast-to-unicast from touching 802.11f packets? Some other ideas? > Obviously I can't modify Broadcom's firmware and drop that obsoleted > standard.