net: dcb: add new common function for set/del of app/rewr entries

In preparation for DCB rewrite. Add a new function for setting and
deleting both app and rewrite entries. Moving this into a separate
function reduces duplicate code, as both type of entries requires the
same set of checks. The function will now iterate through a configurable
nested attribute (app or rewrite attr), validate each attribute and call
the appropriate set- or delete function.

Note that this function always checks for nla_len(attr_itr) <
sizeof(struct dcb_app), which was only done in dcbnl_ieee_set and not in
dcbnl_ieee_del prior to this patch. This means, that any userspace tool
that used to shove in data < sizeof(struct dcb_app) would now receive
-ERANGE.

Signed-off-by: Daniel Machon <[e-mail]>
Reviewed-by: Petr Machata <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/dcb/dcbnl.c

···
 	return err;
 }
 
+/* Set or delete APP table or rewrite table entries. The APP struct is validated
+ * and the appropriate callback function is called.
+ */
+static int dcbnl_app_table_setdel(struct nlattr *attr,
+				  struct net_device *netdev,
+				  int (*setdel)(struct net_device *dev,
+						struct dcb_app *app))
+{
+	struct dcb_app *app_data;
+	enum ieee_attrs_app type;
+	struct nlattr *attr_itr;
+	int rem, err;
+
+	nla_for_each_nested(attr_itr, attr, rem) {
+		type = nla_type(attr_itr);
+
+		if (!dcbnl_app_attr_type_validate(type))
+			continue;
+
+		if (nla_len(attr_itr) < sizeof(struct dcb_app))
+			return -ERANGE;
+
+		app_data = nla_data(attr_itr);
+
+		if (!dcbnl_app_selector_validate(type, app_data->selector))
+			return -EINVAL;
+
+		err = setdel(netdev, app_data);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 /* Handle IEEE 802.1Qaz/802.1Qau/802.1Qbb GET commands. */
 static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 {
···
 	}
 
 	if (ieee[DCB_ATTR_IEEE_APP_TABLE]) {
-		struct nlattr *attr;
-		int rem;
-
-		nla_for_each_nested(attr, ieee[DCB_ATTR_IEEE_APP_TABLE], rem) {
-			enum ieee_attrs_app type = nla_type(attr);
-			struct dcb_app *app_data;
-
-			if (!dcbnl_app_attr_type_validate(type))
-				continue;
-
-			if (nla_len(attr) < sizeof(struct dcb_app)) {
-				err = -ERANGE;
-				goto err;
-			}
-
-			app_data = nla_data(attr);
-
-			if (!dcbnl_app_selector_validate(type,
-							 app_data->selector)) {
-				err = -EINVAL;
-				goto err;
-			}
-
-			if (ops->ieee_setapp)
-				err = ops->ieee_setapp(netdev, app_data);
-			else
-				err = dcb_ieee_setapp(netdev, app_data);
-			if (err)
-				goto err;
-		}
+		err = dcbnl_app_table_setdel(ieee[DCB_ATTR_IEEE_APP_TABLE],
+					     netdev, ops->ieee_setapp ?:
+					     dcb_ieee_setapp);
+		if (err)
+			goto err;
 	}
 
 	if (ieee[DCB_ATTR_DCB_APP_TRUST_TABLE]) {
···
 		return err;
 
 	if (ieee[DCB_ATTR_IEEE_APP_TABLE]) {
-		struct nlattr *attr;
-		int rem;
-
-		nla_for_each_nested(attr, ieee[DCB_ATTR_IEEE_APP_TABLE], rem) {
-			enum ieee_attrs_app type = nla_type(attr);
-			struct dcb_app *app_data;
-
-			if (!dcbnl_app_attr_type_validate(type))
-				continue;
-
-			app_data = nla_data(attr);
-
-			if (!dcbnl_app_selector_validate(type,
-							 app_data->selector)) {
-				err = -EINVAL;
-				goto err;
-			}
-
-			if (ops->ieee_delapp)
-				err = ops->ieee_delapp(netdev, app_data);
-			else
-				err = dcb_ieee_delapp(netdev, app_data);
-			if (err)
-				goto err;
-		}
+		err = dcbnl_app_table_setdel(ieee[DCB_ATTR_IEEE_APP_TABLE],
+					     netdev, ops->ieee_delapp ?:
+					     dcb_ieee_delapp);
+		if (err)
+			goto err;
 	}
 
 err: