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[1/3] batman-adv: Consider fragmentation for needed_headroom

Message ID 20201127173849.19208-2-sw@simonwunderlich.de (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series [1/3] batman-adv: Consider fragmentation for needed_headroom | expand

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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 9 lines checked
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netdev/stable success Stable not CCed

Commit Message

Simon Wunderlich Nov. 27, 2020, 5:38 p.m. UTC 
From: Sven Eckelmann <sven@narfation.org>

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 Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/hard-interface.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

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;
 }