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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Simon Wunderlich" <sw@simonwunderlich.de>,
        "Sven Eckelmann" <sven@narfation.org>,
        "=?UTF-8?q?Linus=20L=C3=BCssing?=" <linus.luessing@c0d3.blue>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.228512641@decadent.org.uk>
Subject: [PATCH 3.16 394/410] batman-adv: fix multicast-via-unicast
 transmission with AP isolation
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Linus Lüssing <linus.luessing@c0d3.blue>

commit f8fb3419ead44f9a3136995acd24e35da4525177 upstream.

For multicast frames AP isolation is only supposed to be checked on
the receiving nodes and never on the originating one.

Furthermore, the isolation or wifi flag bits should only be intepreted
as such for unicast and never multicast TT entries.

By injecting flags to the multicast TT entry claimed by a single
target node it was verified in tests that this multicast address
becomes unreachable, leading to packet loss.

Omitting the "src" parameter to the batadv_transtable_search() call
successfully skipped the AP isolation check and made the target
reachable again.

Fixes: 1d8ab8d3c176 ("batman-adv: Modified forwarding behaviour for multicast packets")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 net/batman-adv/multicast.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -398,8 +398,8 @@ static struct batadv_orig_node *
 batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
 			      struct ethhdr *ethhdr)
 {
-	return batadv_transtable_search(bat_priv, ethhdr->h_source,
-					ethhdr->h_dest, BATADV_NO_FLAGS);
+	return batadv_transtable_search(bat_priv, NULL, ethhdr->h_dest,
+					BATADV_NO_FLAGS);
 }
 
 /**