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batman-adv: Consider fragmentation for needed_headroom

Message ID 20201126171832.1064799-1-sven@narfation.org
State Accepted, archived
Delegated to: Simon Wunderlich
Headers show
Series batman-adv: Consider fragmentation for needed_headroom | expand

Commit Message

Sven Eckelmann Nov. 26, 2020, 5:18 p.m. UTC
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 splitted.

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

Reported-by: Linus L├╝ssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
 net/batman-adv/hard-interface.c | 3 +++
 1 file changed, 3 insertions(+)


Sven Eckelmann Nov. 26, 2020, 6:11 p.m. UTC | #1
Fixes: e2b4301f4e2d ("batman-adv: Add lower layer needed_(head|tail)room to own ones")
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diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index f122e448..bbedb9a4 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -553,6 +553,9 @@  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;