Add support to get devlink resources

- Update nl package with new netlink attribute types and consts
- Define structs to model devlink device resources
- Add DevlinkGetDeviceResources method to return device resources
- Add basic test

Signed-off-by: adrianc <adrianc@nvidia.com>

devlink_linux.go

@@ -84,6 +84,169 @@ type DevlinkDeviceInfo struct {
 	FwUndi         string
 }
 
+// DevlinkResource represents a device resource
+type DevlinkResource struct {
+	Name            string
+	ID              uint64
+	Size            uint64
+	SizeNew         uint64
+	SizeMin         uint64
+	SizeMax         uint64
+	SizeGranularity uint64
+	PendingChange   bool
+	Unit            uint8
+	SizeValid       bool
+	OCCValid        bool
+	OCCSize         uint64
+	Parent          *DevlinkResource
+	Children        []DevlinkResource
+}
+
+// parseAttributes parses provided Netlink Attributes and populates DevlinkResource, returns error if occured
+func (dlr *DevlinkResource) parseAttributes(attrs map[uint16]syscall.NetlinkRouteAttr) error {
+	var attr syscall.NetlinkRouteAttr
+	var ok bool
+
+	// mandatory attributes
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_ID]
+	if !ok {
+		return fmt.Errorf("missing resource id")
+	}
+	dlr.ID = native.Uint64(attr.Value)
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_NAME]
+	if !ok {
+		return fmt.Errorf("missing resource name")
+	}
+	dlr.Name = nl.BytesToString(attr.Value)
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_SIZE]
+	if !ok {
+		return fmt.Errorf("missing resource size")
+	}
+	dlr.Size = native.Uint64(attr.Value)
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_SIZE_GRAN]
+	if !ok {
+		return fmt.Errorf("missing resource size granularity")
+	}
+	dlr.SizeGranularity = native.Uint64(attr.Value)
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_UNIT]
+	if !ok {
+		return fmt.Errorf("missing resource unit")
+	}
+	dlr.Unit = uint8(attr.Value[0])
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_SIZE_MIN]
+	if !ok {
+		return fmt.Errorf("missing resource size min")
+	}
+	dlr.SizeMin = native.Uint64(attr.Value)
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_SIZE_MAX]
+	if !ok {
+		return fmt.Errorf("missing resource size max")
+	}
+	dlr.SizeMax = native.Uint64(attr.Value)
+
+	// optional attributes
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_OCC]
+	if ok {
+		dlr.OCCSize = native.Uint64(attr.Value)
+		dlr.OCCValid = true
+	}
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_SIZE_VALID]
+	if ok {
+		dlr.SizeValid = uint8(attr.Value[0]) != 0
+	}
+
+	dlr.SizeNew = dlr.Size
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_SIZE_NEW]
+	if ok {
+		dlr.SizeNew = native.Uint64(attr.Value)
+	}
+
+	dlr.PendingChange = dlr.Size != dlr.SizeNew
+
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_LIST]
+	if ok {
+		// handle nested resoruces recursively
+		subResources, err := nl.ParseRouteAttr(attr.Value)
+		if err != nil {
+			return err
+		}
+
+		for _, subresource := range subResources {
+			resource := DevlinkResource{Parent: dlr}
+			attrs, err := nl.ParseRouteAttrAsMap(subresource.Value)
+			if err != nil {
+				return err
+			}
+			err = resource.parseAttributes(attrs)
+			if err != nil {
+				return fmt.Errorf("failed to parse child resource, parent:%s. %w", dlr.Name, err)
+			}
+			dlr.Children = append(dlr.Children, resource)
+		}
+	}
+	return nil
+}
+
+// DevlinkResources represents all devlink resources of a devlink device
+type DevlinkResources struct {
+	Bus       string
+	Device    string
+	Resources []DevlinkResource
+}
+
+// parseAttributes parses provided Netlink Attributes and populates DevlinkResources, returns error if occured
+func (dlrs *DevlinkResources) parseAttributes(attrs map[uint16]syscall.NetlinkRouteAttr) error {
+	var attr syscall.NetlinkRouteAttr
+	var ok bool
+
+	// Bus
+	attr, ok = attrs[nl.DEVLINK_ATTR_BUS_NAME]
+	if !ok {
+		return fmt.Errorf("missing bus name")
+	}
+	dlrs.Bus = nl.BytesToString(attr.Value)
+
+	// Device
+	attr, ok = attrs[nl.DEVLINK_ATTR_DEV_NAME]
+	if !ok {
+		return fmt.Errorf("missing device name")
+	}
+	dlrs.Device = nl.BytesToString(attr.Value)
+
+	// Resource List
+	attr, ok = attrs[nl.DEVLINK_ATTR_RESOURCE_LIST]
+	if !ok {
+		return fmt.Errorf("missing resource list")
+	}
+
+	resourceAttrs, err := nl.ParseRouteAttr(attr.Value)
+	if err != nil {
+		return err
+	}
+
+	for _, resourceAttr := range resourceAttrs {
+		resource := DevlinkResource{}
+		attrs, err := nl.ParseRouteAttrAsMap(resourceAttr.Value)
+		if err != nil {
+			return err
+		}
+		err = resource.parseAttributes(attrs)
+		if err != nil {
+			return fmt.Errorf("failed to parse root resoruces, %w", err)
+		}
+		dlrs.Resources = append(dlrs.Resources, resource)
+	}
+
+	return nil
+}
+
 func parseDevLinkDeviceList(msgs [][]byte) ([]*DevlinkDevice, error) {
 	devices := make([]*DevlinkDevice, 0, len(msgs))
 	for _, m := range msgs {
@@ -443,6 +606,35 @@ func (h *Handle) DevLinkGetPortByIndex(Bus string, Device string, PortIndex uint
 	return port, err
 }
 
+// DevlinkGetDeviceResources returns devlink device resources
+func DevlinkGetDeviceResources(bus string, device string) (*DevlinkResources, error) {
+	return pkgHandle.DevlinkGetDeviceResources(bus, device)
+}
+
+// DevlinkGetDeviceResources returns devlink device resources
+func (h *Handle) DevlinkGetDeviceResources(bus string, device string) (*DevlinkResources, error) {
+	_, req, err := h.createCmdReq(nl.DEVLINK_CMD_RESOURCE_DUMP, bus, device)
+	if err != nil {
+		return nil, err
+	}
+
+	respmsg, err := req.Execute(unix.NETLINK_GENERIC, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	var resources DevlinkResources
+	for _, m := range respmsg {
+		attrs, err := nl.ParseRouteAttrAsMap(m[nl.SizeofGenlmsg:])
+		if err != nil {
+			return nil, err
+		}
+		resources.parseAttributes(attrs)
+	}
+
+	return &resources, nil
+}
+
 // DevLinkGetPortByIndex provides a pointer to devlink portand nil error,
 // otherwise returns an error code.
 func DevLinkGetPortByIndex(Bus string, Device string, PortIndex uint32) (*DevlinkPort, error) {