net/mlx5e: flower: validate encapsulation control flags

Encapsulation control flags are currently not used anywhere,
so all flags are currently unsupported by all drivers.

This patch adds validation of this assumption, so that
encapsulation flags may be used in the future.

In case any encapsulation control flags are masked,
flow_rule_match_has_enc_control_flags() sets a NL extended
error message, and we return -EOPNOTSUPP.

Only compile tested.
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Reviewed-by: Davide Caratti <dcaratti@redhat.com>
Link: https://lore.kernel.org/r/20240609173358.193178-4-ast@fiberby.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c

@@ -850,6 +850,12 @@ int mlx5e_tc_tun_parse(struct net_device *filter_dev,
 		flow_rule_match_enc_control(rule, &match);
 		addr_type = match.key->addr_type;
 
+		if (flow_rule_has_enc_control_flags(match.mask->flags,
+						    extack)) {
+			err = -EOPNOTSUPP;
+			goto out;
+		}
+
 		/* For tunnel addr_type used same key id`s as for non-tunnel */
 		if (addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
 			struct flow_match_ipv4_addrs match;