[PATCH net-next] net: qede: flower: validate control flags

["Asbjørn Sloth Tønnesen" <ast@fiberby.net>]

This driver currently doesn't support any flower control flags.

Implement check for control flags, such as can be set through
`tc flower ... ip_flags frag`.

Since qede_parse_flow_attr() are called by both qede_add_tc_flower_fltr()
and qede_flow_spec_to_rule(), as the latter doesn't having access to
extack, then flow_rule_*_control_flags() can't be used in this driver.

This patch therefore re-implements flow_rule_match_has_control_flags(),
but with error messaging via DP_NOTICE, instead of NL_SET_ERR_MSG_FMT_MOD.

So in case any control flags are masked, we call DP_NOTICE() and
return -EOPNOTSUPP.

Only compile-tested.

Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
---

This is AFAICT the last driver which didn't validate these flags.

$ git grep FLOW_DISSECTOR_KEY_CONTROL drivers/
$ git grep 'flow_rule_.*_control_flags' drivers/

 drivers/net/ethernet/qlogic/qede/qede_filter.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qede/qede_filter.c b/drivers/net/ethernet/qlogic/qede/qede_filter.c
index a5ac21a0ee33..40f72e700d8e 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_filter.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_filter.c
@@ -1843,6 +1843,19 @@ qede_parse_flow_attr(struct qede_dev *edev, __be16 proto,
 		return -EPROTONOSUPPORT;
 	}
 
+	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_CONTROL)) {
+		struct flow_match_control match;
+
+		flow_rule_match_control(rule, &match);
+
+		if (match.mask->flags) {
+			DP_NOTICE(edev,
+				  "Unsupported match on control.flags %#x",
+				  match.mask->flags);
+			return -EOPNOTSUPP;
+		}
+	}
+
 	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_BASIC)) {
 		struct flow_match_basic match;
 
-- 
2.43.0