Re: [PATCH net-next v4 3/4] net: selftests: add checksum mode support and SW checksum handling

[Jakub Kicinski <kuba@kernel.org>]

On Thu, 15 May 2025 10:30:59 +0200 Oleksij Rempel wrote:
> +enum net_test_checksum_mode {
> +	NET_TEST_CHECKSUM_COMPLETE,

Why COMPLETE? that means skb has checksum of the complete data.
If packet requires no checksumming you should probably use CHECKSUM_NONE

> +	switch (iph->protocol) {
> +	case IPPROTO_TCP:
> +		if (!pskb_may_pull(skb,
> +				   transport_offset + sizeof(struct tcphdr)))

Why are you so diligently checking if you can pull for the SW sum but
not for the HW sum? Both of them update the same header fields :)

> +static int net_test_setup_hw_csum(struct sk_buff *skb, struct iphdr *iph)
> +{
> +	u16 csum_offset;
> +
> +	skb->ip_summed = CHECKSUM_PARTIAL;
> +	skb->csum = 0;
> +
> +	switch (iph->protocol) {
> +	case IPPROTO_TCP:
> +		if (!tcp_hdr(skb))
> +			return -EINVAL;
> +		tcp_hdr(skb)->check = 0;

this filed should be filled with pseudo header checksum for HW offload,
not with 0, like the existing code did
-- 
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