Commit 8d89661a authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Paolo Abeni
Browse files

net: selftests: fix TCP packet checksum 



The length in the pseudo header should be the length of the L3 payload
AKA the L4 header+payload. The selftest code builds the packet from
the lower layers up, so all the headers are pushed already when it
constructs L4. We need to subtract the lower layer headers from skb->len.

Fixes: 3e1e58d6 ("net: add generic selftest support")
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarGerhard Engleder <gerhard@engleder-embedded.com>
Reported-by: default avatarOleksij Rempel <o.rempel@pengutronix.de>
Tested-by: default avatarOleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: default avatarOleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20250624183258.3377740-1-kuba@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent a433791a

net/core/selftests.c

+3 −2
Original line number Diff line number Diff line
@@ -160,8 +160,9 @@ static struct sk_buff *net_test_get_skb(struct net_device *ndev, 
	skb->csum = 0;

	skb->ip_summed = CHECKSUM_PARTIAL;

	if (attr->tcp) {

		thdr->check = ~tcp_v4_check(skb->len, ihdr->saddr,

					    ihdr->daddr, 0);

		int l4len = skb->len - skb_transport_offset(skb);



		thdr->check = ~tcp_v4_check(l4len, ihdr->saddr, ihdr->daddr, 0);

		skb->csum_start = skb_transport_header(skb) - skb->head;

		skb->csum_offset = offsetof(struct tcphdr, check);

	} else {