Merge branch 'flower-control-flags'

Asbjørn Sloth Tønnesen says:

====================
flower: validate control flags

I have reviewed the flower control flags code.
In all, but one (sfc), the flags field wasn't
checked properly for unsupported flags.

In this series I have only included a single example
user for each helper function. Once the helpers are in,
I will submit patches for all other drivers implementing
flower.

After which there will be:
- 6 drivers using flow_rule_is_supp_control_flags()
- 8 drivers using flow_rule_has_control_flags()
- 11 drivers using flow_rule_match_has_control_flags()

---
Changelog:

v3:
- Added Reviewed-by from Louis Peens (first two patches)
- Properly fixed kernel-doc format

v2: https://lore.kernel.org/netdev/20240410093235.5334-1-ast@fiberby.net/
- Squashed the 3 helper functions to one commmit (requested by Baowen Zheng)
- Renamed helper functions to avoid double negatives (suggested by Louis Peens)
- Reverse booleans in some functions and callsites to align with new names
- Fix autodoc format

v1: https://lore.kernel.org/netdev/20240408130927.78594-1-ast@fiberby.net/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/ksz9477_tc_flower.c

@@ -124,6 +124,9 @@ static int ksz9477_flower_parse_key(struct ksz_device *dev, int port,
 		return -EOPNOTSUPP;
 	}
 
+	if (flow_rule_match_has_control_flags(rule, extack))
+		return -EOPNOTSUPP;
+
 	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_BASIC) ||
 	    flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 		ret = ksz9477_flower_parse_key_l2(dev, port, extack, rule,

drivers/net/ethernet/marvell/prestera/prestera_flower.c

@@ -229,6 +229,10 @@ static int prestera_flower_parse(struct prestera_flow_block *block,
 
 		flow_rule_match_control(f_rule, &match);
 		addr_type = match.key->addr_type;
+
+		if (flow_rule_has_control_flags(match.mask->flags,
+						f->common.extack))
+			return -EOPNOTSUPP;
 	}
 
 	if (flow_rule_match_key(f_rule, FLOW_DISSECTOR_KEY_BASIC)) {

drivers/net/ethernet/netronome/nfp/flower/offload.c

@@ -527,10 +527,10 @@ nfp_flower_calculate_key_layers(struct nfp_app *app,
 		struct flow_match_control ctl;
 
 		flow_rule_match_control(rule, &ctl);
-		if (ctl.key->flags & ~NFP_FLOWER_SUPPORTED_CTLFLAGS) {
-			NL_SET_ERR_MSG_MOD(extack, "unsupported offload: match on unknown control flag");
+
+		if (!flow_rule_is_supp_control_flags(NFP_FLOWER_SUPPORTED_CTLFLAGS,
+						     ctl.mask->flags, extack))
 			return -EOPNOTSUPP;
-		}
 	}
 
 	ret_key_ls->key_layer = key_layer;

include/net/flow_offload.h

@@ -449,6 +449,61 @@ static inline bool flow_rule_match_key(const struct flow_rule *rule,
 	return dissector_uses_key(rule->match.dissector, key);
 }
 
+/**
+ * flow_rule_is_supp_control_flags() - check for supported control flags
+ * @supp_flags: control flags supported by driver
+ * @ctrl_flags: control flags present in rule
+ * @extack: The netlink extended ACK for reporting errors.
+ *
+ * Return: true if only supported control flags are set, false otherwise.
+ */
+static inline bool flow_rule_is_supp_control_flags(const u32 supp_flags,
+						   const u32 ctrl_flags,
+						   struct netlink_ext_ack *extack)
+{
+	if (likely((ctrl_flags & ~supp_flags) == 0))
+		return true;
+
+	NL_SET_ERR_MSG_FMT_MOD(extack,
+			       "Unsupported match on control.flags %#x",
+			       ctrl_flags);
+
+	return false;
+}
+
+/**
+ * flow_rule_has_control_flags() - check for presence of any control flags
+ * @ctrl_flags: control flags present in rule
+ * @extack: The netlink extended ACK for reporting errors.
+ *
+ * Return: true if control flags are set, false otherwise.
+ */
+static inline bool flow_rule_has_control_flags(const u32 ctrl_flags,
+					       struct netlink_ext_ack *extack)
+{
+	return !flow_rule_is_supp_control_flags(0, ctrl_flags, extack);
+}
+
+/**
+ * flow_rule_match_has_control_flags() - match and check for any control flags
+ * @rule: The flow_rule under evaluation.
+ * @extack: The netlink extended ACK for reporting errors.
+ *
+ * Return: true if control flags are set, false otherwise.
+ */
+static inline bool flow_rule_match_has_control_flags(struct flow_rule *rule,
+						     struct netlink_ext_ack *extack)
+{
+	struct flow_match_control match;
+
+	if (!flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_CONTROL))
+		return false;
+
+	flow_rule_match_control(rule, &match);
+
+	return flow_rule_has_control_flags(match.mask->flags, extack);
+}
+
 struct flow_stats {
 	u64	pkts;
 	u64	bytes;