batman-adv: Fix transmission of final, 16th fragment

commit 51c6b429c0 upstream.

Trying to split and transmit a unicast packet in 16 parts will fail for
the final fragment: After having sent the 15th one with a frag_packet.no
index of 14, we will increase the the index to 15 - and return with an
error code immediately, even though one more fragment is due for
transmission and allowed.

Fixing this issue by moving the check before incrementing the index.

While at it, adding an unlikely(), because the check is actually more of
an assertion.

Fixes: ee75ed8887 ("batman-adv: Fragment and send skbs larger than mtu")
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>
[bwh: Backported to 3.16: don't return an error code]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Linus Lüssing 2017-02-13 20:44:31 +01:00 • committed by Ben Hutchings
commit 9bbd855ae3