tree d2b955f9415be686637950c7e787125dadc8ae82
parent 24443bf39b9bd553bbe3bc0063809421c1052f44
author Marek Lindner <mareklindner@neomailbox.ch> 1584397856 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1584691674 +0100

batman-adv: prevent TT request storms by not sending inconsistent TT TLVLs

commit 16116dac23396e73c01eeee97b102e4833a4b205 upstream.

A translation table TVLV changset sent with an OGM consists
of a number of headers (one per VLAN) plus the changeset
itself (addition and/or deletion of entries).

The per-VLAN headers are used by OGM recipients for consistency
checks. Said consistency check might determine that a full
translation table request is needed to restore consistency. If
the TT sender adds per-VLAN headers of empty VLANs into the OGM,
recipients are led to believe to have reached an inconsistent
state and thus request a full table update. The full table does
not contain empty VLANs (due to missing entries) the cycle
restarts when the next OGM is issued.

Consequently, when the translation table TVLV headers are
composed, empty VLANs are to be excluded.

Fixes: 21a57f6e7a3b ("batman-adv: make the TT CRC logic VLAN specific")
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>