Re: [PATCH ipsec-next v8 08/16] xfrm: iptfs: add user packet (tunnel ingress) handling

[Simon Horman <horms@kernel.org>]

On Sun, Aug 04, 2024 at 04:33:37PM -0400, Christian Hopps wrote:
> From: Christian Hopps <chopps@labn.net>
> 
> Add tunnel packet output functionality. This is code handles
> the ingress to the tunnel.
> 
> Signed-off-by: Christian Hopps <chopps@labn.net>

...

> +/**
> + * iptfs_prepare_output() -  prepare the skb for output
> + * @x: xfrm state
> + * @skb: the packet
> + *
> + * Return: Error value, if 0 then skb values should be as follows:
> + *    - transport_header should point at ESP header
> + *    - network_header should point at Outer IP header
> + *    - mac_header should point at protocol/nexthdr of the outer IP
> + */
> +static int iptfs_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
> +{
> +	if (x->outer_mode.family == AF_INET)
> +		return iptfs_encap_add_ipv4(x, skb);
> +	if (x->outer_mode.family == AF_INET6) {
> +#if IS_ENABLED(CONFIG_IPV6)
> +		return iptfs_encap_add_ipv6(x, skb);

iptfs_encap_add_ipv6 is flagged as unused when IPV6 is not enabled.
Perhaps it should also be wrapped in a CONFIG_IPV6 check.

> +#else
> +		WARN_ON_ONCE(1);
> +		return -EAFNOSUPPORT;
> +#endif
> +	}
> +	WARN_ON_ONCE(1);
> +	return -EOPNOTSUPP;
> +}
> +

...