From a1bfc093a00c6e5f111483013f8d2519c7d66615 Mon Sep 17 00:00:00 2001 From: Kurt Kanzenbach Date: Fri, 15 Apr 2022 12:33:20 +0200 Subject: [PATCH] net: dsa: hellcreek: Calculate checksums in tagger In case the checksum calculation is offloaded to the DSA master network interface, it will include the switch trailing tag. As soon as the switch strips that tag on egress, the calculated checksum is wrong. Therefore, add the checksum calculation to the tagger (if required) before adding the switch tag. This way, the hellcreek code works with all DSA master interfaces regardless of their declared feature set. Fixes: f042e73d9af9 ("net: dsa: Add tag handling for Hirschmann Hellcreek switches") Signed-off-by: Kurt Kanzenbach Reviewed-by: Florian Fainelli Link: https://lore.kernel.org/r/20220415103320.90657-1-kurt@linutronix.de Signed-off-by: Paolo Abeni --- net/dsa/tag_hellcreek.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/dsa/tag_hellcreek.c b/net/dsa/tag_hellcreek.c index f64b805303cd7..eb204ad36eeec 100644 --- a/net/dsa/tag_hellcreek.c +++ b/net/dsa/tag_hellcreek.c @@ -21,6 +21,14 @@ static struct sk_buff *hellcreek_xmit(struct sk_buff *skb, struct dsa_port *dp = dsa_slave_to_port(dev); u8 *tag; + /* Calculate checksums (if required) before adding the trailer tag to + * avoid including it in calculations. That would lead to wrong + * checksums after the switch strips the tag. + */ + if (skb->ip_summed == CHECKSUM_PARTIAL && + skb_checksum_help(skb)) + return NULL; + /* Tag encoding */ tag = skb_put(skb, HELLCREEK_TAG_LEN); *tag = BIT(dp->index); -- 2.39.5