4.9-stable review patch. If anyone has any objections, please let me know.
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From: Matthias Schiffer mschiffer@universe-factory.net
[ Upstream commit 3bf2a09da956b43ecfaa630a2ef9a477f991a46a ]
A more sophisticated implementation could try to combine fragment checksums when all fragments have CHECKSUM_COMPLETE and are split at even offsets. For now, we just set ip_summed to CHECKSUM_NONE to avoid "hw csum failure" warnings in the kernel log when fragmented frames are received. In consequence, skb_pull_rcsum() can be replaced with skb_pull().
Note that in usual setups, packets don't reach batman-adv with CHECKSUM_COMPLETE (I assume NICs bail out of checksumming when they see batadv's ethtype?), which is why the log messages do not occur on every system using batman-adv. I could reproduce this issue by stacking batman-adv on top of a VXLAN interface.
Fixes: 610bfc6bc99b ("batman-adv: Receive fragmented packets and merge") Tested-by: Maximilian Wilhelm max@sdn.clinic Signed-off-by: Matthias Schiffer mschiffer@universe-factory.net Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/batman-adv/fragmentation.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -276,7 +276,8 @@ batadv_frag_merge_packets(struct hlist_h /* Move the existing MAC header to just before the payload. (Override * the fragment header.) */ - skb_pull_rcsum(skb_out, hdr_size); + skb_pull(skb_out, hdr_size); + skb_out->ip_summed = CHECKSUM_NONE; memmove(skb_out->data - ETH_HLEN, skb_mac_header(skb_out), ETH_HLEN); skb_set_mac_header(skb_out, -ETH_HLEN); skb_reset_network_header(skb_out);