The following commit has been merged in the master branch: commit 4ca23e2c2074465bff55ea14221175fecdf63c5f Author: Sven Eckelmann sven@narfation.org Date: Thu Nov 26 18:15:06 2020 +0100

batman-adv: Consider fragmentation for needed_headroom

If a batman-adv packets has to be fragmented, then the original batman-adv packet header is not stripped away. Instead, only a new header is added in front of the packet after it was split.

This size must be considered to avoid cost intensive reallocations during the transmission through the various device layers.

Fixes: 7bca68c7844b ("batman-adv: Add lower layer needed_(head|tail)room to own ones") Reported-by: Linus L��ssing linus.luessing@c0d3.blue Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index dad99641df2a..33904595fc56 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -554,6 +554,9 @@ static void batadv_hardif_recalc_extra_skbroom(struct net_device *soft_iface) needed_headroom = lower_headroom + (lower_header_len - ETH_HLEN); needed_headroom += batadv_max_header_len();

+ /* fragmentation headers don't strip the unicast/... header */ + needed_headroom += sizeof(struct batadv_frag_packet); + soft_iface->needed_headroom = needed_headroom; soft_iface->needed_tailroom = lower_tailroom; }