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: 7bca68c784 ("batman-adv: Add lower layer needed_(head|tail)room to own ones")
Reported-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
This commit is contained in:
Sven Eckelmann 2020-11-26 18:15:06 +01:00 committed by Simon Wunderlich
parent 14a2e551fa
commit 4ca23e2c20

View File

@ -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;
}