From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from youngberry.canonical.com ([91.189.89.112]:46652 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932922AbbI3JyL (ORCPT ); Wed, 30 Sep 2015 05:54:11 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: =?UTF-8?q?Linus=20L=C3=BCssing?= , Marek Lindner , Antonio Quartulli , Luis Henriques Subject: [PATCH 3.16.y-ckt 099/133] batman-adv: fix counter for multicast supporting nodes Date: Wed, 30 Sep 2015 10:50:47 +0100 Message-Id: <1443606681-7124-100-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1443606681-7124-1-git-send-email-luis.henriques@canonical.com> References: <1443606681-7124-1-git-send-email-luis.henriques@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 3.16.7-ckt18 -stable review patch. If anyone has any objections, please let me know. ------------------ From: =?UTF-8?q?Linus=20L=C3=BCssing?= commit e8829f007e982a9a8fb4023109233d5f344d4657 upstream. A miscounting of nodes having multicast optimizations enabled can lead to multicast packet loss in the following scenario: If the first OGM a node receives from another one has no multicast optimizations support (no multicast tvlv) then we are missing to increase the counter. This potentially leads to the wrong assumption that we could safely use multicast optimizations. Fixings this by increasing the counter if the initial OGM has the multicast TVLV unset, too. Introduced by 60432d756cf06e597ef9da511402dd059b112447 ("batman-adv: Announce new capability via multicast TVLV") Reported-by: Tobias Hachmer Signed-off-by: Linus Lüssing Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli Signed-off-by: Luis Henriques --- net/batman-adv/multicast.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index a5e457ec4916..fe57bde57a2c 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -686,11 +686,13 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, if (orig_initialized) atomic_dec(&bat_priv->mcast.num_disabled); orig->capabilities |= BATADV_ORIG_CAPA_HAS_MCAST; - /* If mcast support is being switched off increase the disabled - * mcast node counter. + /* If mcast support is being switched off or if this is an initial + * OGM without mcast support then increase the disabled mcast + * node counter. */ } else if (!orig_mcast_enabled && - orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST) { + (orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST || + !orig_initialized)) { atomic_inc(&bat_priv->mcast.num_disabled); orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_MCAST; }