[PATCH 5.10 19/23] batman-adv: tt: don't merge change entries with different VIDs

[Sven Eckelmann <sven@narfation.org>]

commit f08e06c2d5c3e2434e7c773f2213f4a7dce6bc1e upstream.

batadv_tt_local_event() merges/cancels events for the same client which
would conflict or be duplicates. The matching of the queued events only
compares the MAC address - the VLAN ID stored in each event is ignored.

If a MAC would now appear on multiple VID, the two ADD change events (for
VID 1 and VID 2) would be merged to a single vid event. The remote can
therefore not calculate the correct TT table and desync. A full translation
table exchange is required to recover from this state.

A check of VID is therefore necessary to avoid such wrong merges/cancels.

Cc: stable@kernel.org
Fixes: c018ad3de61a ("batman-adv: add the VLAN ID attribute to the TT entry")
[ Context ]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/translation-table.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 79da90b9cf065..c323660897d43 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -486,6 +486,9 @@ static void batadv_tt_local_event(struct batadv_priv *bat_priv,
 		if (!batadv_compare_eth(entry->change.addr, common->addr))
 			continue;
 
+		if (entry->change.vid != tt_change_node->change.vid)
+			continue;
+
 		/* DEL+ADD in the same orig interval have no effect and can be
 		 * removed to avoid silly behaviour on the receiver side. The
 		 * other way around (ADD+DEL) can happen in case of roaming of
-- 
2.47.3