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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 9B9ABC4167B for ; Thu, 16 Sep 2021 17:41:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8467F6023D for ; Thu, 16 Sep 2021 17:41:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355181AbhIPRlL (ORCPT ); Thu, 16 Sep 2021 13:41:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:50294 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348538AbhIPRc3 (ORCPT ); Thu, 16 Sep 2021 13:32:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D5AA761504; Thu, 16 Sep 2021 16:47:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631810871; bh=xHfzP72TZyDPRk8pGAwmlKS+B0g1x+9BYa0SUdCdils=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=um3/AnRm6J1EtDpVf4e7hSg8o2/7oqq/V3Zq+PJs0UkLUKgUTJh9koJkdqUxE7dnK HJFIYj8TefTGzBHUaR8/wjLHz7FTOQFkUWys7aYVXjcyMbY4Lbfkk8PGcH/Iuxez+J NXy3JCFXRDk50W21l1juEd607qlr064r311Ahcps= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Almbladh , Johannes Berg , Sasha Levin Subject: [PATCH 5.14 297/432] mac80211: Fix monitor MTU limit so that A-MSDUs get through Date: Thu, 16 Sep 2021 18:00:46 +0200 Message-Id: <20210916155820.896912477@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155810.813340753@linuxfoundation.org> References: <20210916155810.813340753@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Almbladh [ Upstream commit 79f5962baea74ce1cd4e5949598944bff854b166 ] The maximum MTU was set to 2304, which is the maximum MSDU size. While this is valid for normal WLAN interfaces, it is too low for monitor interfaces. A monitor interface may receive and inject MPDU frames, and the maximum MPDU frame size is larger than 2304. The MPDU may also contain an A-MSDU frame, in which case the size may be much larger than the MTU limit. Since the maximum size of an A-MSDU depends on the PHY mode of the transmitting STA, it is not possible to set an exact MTU limit for a monitor interface. Now the maximum MTU for a monitor interface is unrestricted. Signed-off-by: Johan Almbladh Link: https://lore.kernel.org/r/20210628123246.2070558-1-johan.almbladh@anyfinetworks.com Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/iface.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 1e5e9fc45523..cd96cd337aa8 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -2001,9 +2001,16 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name, netdev_set_default_ethtool_ops(ndev, &ieee80211_ethtool_ops); - /* MTU range: 256 - 2304 */ + /* MTU range is normally 256 - 2304, where the upper limit is + * the maximum MSDU size. Monitor interfaces send and receive + * MPDU and A-MSDU frames which may be much larger so we do + * not impose an upper limit in that case. + */ ndev->min_mtu = 256; - ndev->max_mtu = local->hw.max_mtu; + if (type == NL80211_IFTYPE_MONITOR) + ndev->max_mtu = 0; + else + ndev->max_mtu = local->hw.max_mtu; ret = cfg80211_register_netdevice(ndev); if (ret) { -- 2.30.2