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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 1E838C433E0 for ; Tue, 11 Aug 2020 16:43:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE9FF206DC for ; Tue, 11 Aug 2020 16:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597164184; bh=GI6OEs1EfIlNFpfrrNWl3O0cjrdYTbDR04UTKujfyXE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=cRgbIgZYzKWWDEOPR05jhAXIqfX9xRu9P3Eo56wRH3ksR9dQwZ8uAVyOtgRyEUkX4 wu6y2nuCKNJz9FtyavN/agOrlIFAqFbLggixD6Q22bbjQWEl18/3zR8HVndF/u0L3A zryUhFc4c9jnVtUnD6BYS6glQ1lB4l0Rh57Hzd2Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729219AbgHKQm5 (ORCPT ); Tue, 11 Aug 2020 12:42:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:47230 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729205AbgHKQm5 (ORCPT ); Tue, 11 Aug 2020 12:42:57 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 19747206DC; Tue, 11 Aug 2020 16:42:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597164176; bh=GI6OEs1EfIlNFpfrrNWl3O0cjrdYTbDR04UTKujfyXE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RZBca4EWElRWJlHtTDeWGhKFRJVENyEt/Hllb0Llzwu6v+APOx2fBW3d1tiHbm/sH BVyaYaGxrgceaNfydKWpeqKem4u07/v7bTtL3EbQ0BzHtt8z1lA66dUArDrY8id0lC SiiaPJhBFhy31BOx4BCTpIuzKAHJyEnBNu8vdbJs= Date: Tue, 11 Aug 2020 12:42:55 -0400 From: Sasha Levin To: Vladimir Oltean Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Vladimir Oltean , "David S . Miller" , netdev@vger.kernel.org Subject: Re: [PATCH AUTOSEL 5.7 03/60] net: mscc: ocelot: fix encoding destination ports into multicast IPv4 address Message-ID: <20200811164255.GJ2975990@sasha-vm> References: <20200810191028.3793884-1-sashal@kernel.org> <20200810191028.3793884-3-sashal@kernel.org> <20200810210108.ystlnglj4atyfrfh@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200810210108.ystlnglj4atyfrfh@skbuf> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Aug 11, 2020 at 12:01:08AM +0300, Vladimir Oltean wrote: >Hi Sasha, > >On Mon, Aug 10, 2020 at 03:09:31PM -0400, Sasha Levin wrote: >> From: Vladimir Oltean >> >> [ Upstream commit 0897ecf7532577bda3dbcb043ce046a96948889d ] >> >> The ocelot hardware designers have made some hacks to support multicast >> IPv4 and IPv6 addresses. Normally, the MAC table matches on MAC >> addresses and the destination ports are selected through the DEST_IDX >> field of the respective MAC table entry. The DEST_IDX points to a Port >> Group ID (PGID) which contains the bit mask of ports that frames should >> be forwarded to. But there aren't a lot of PGIDs (only 80 or so) and >> there are clearly many more IP multicast addresses than that, so it >> doesn't scale to use this PGID mechanism, so something else was done. >> Since the first portion of the MAC address is known, the hack they did >> was to use a single PGID for _flooding_ unknown IPv4 multicast >> (PGID_MCIPV4 == 62), but for known IP multicast, embed the destination >> ports into the first 3 bytes of the MAC address recorded in the MAC >> table. >> >> The VSC7514 datasheet explains it like this: >> >> 3.9.1.5 IPv4 Multicast Entries >> >> MAC table entries with the ENTRY_TYPE = 2 settings are interpreted >> as IPv4 multicast entries. >> IPv4 multicasts entries match IPv4 frames, which are classified to >> the specified VID, and which have DMAC = 0x01005Exxxxxx, where >> xxxxxx is the lower 24 bits of the MAC address in the entry. >> Instead of a lookup in the destination mask table (PGID), the >> destination set is programmed as part of the entry MAC address. This >> is shown in the following table. >> >> Table 78: IPv4 Multicast Destination Mask >> >> Destination Ports Record Bit Field >> --------------------------------------------- >> Ports 10-0 MAC[34-24] >> >> Example: All IPv4 multicast frames in VLAN 12 with MAC 01005E112233 are >> to be forwarded to ports 3, 8, and 9. This is done by inserting the >> following entry in the MAC table entry: >> VALID = 1 >> VID = 12 >> MAC = 0x000308112233 >> ENTRY_TYPE = 2 >> DEST_IDX = 0 >> >> But this procedure is not at all what's going on in the driver. In fact, >> the code that embeds the ports into the MAC address looks like it hasn't >> actually been tested. This patch applies the procedure described in the >> datasheet. >> >> Since there are many other fixes to be made around multicast forwarding >> until it works properly, there is no real reason for this patch to be >> backported to stable trees, or considered a real fix of something that >> should have worked. >> >> Signed-off-by: Vladimir Oltean >> Signed-off-by: David S. Miller >> Signed-off-by: Sasha Levin >> --- > >Could you please drop this patch from the 'stable' queues for 5.7 and >5.8? I haven't tested it on older kernels and without the other patches >sent in that series. I would like to avoid unexpected regressions if >possible. Will do, thanks! -- Thanks, Sasha