Method ClassList

class_linux.go:218–305

ClassList gets a list of classes in the system. Equivalent to: `tc class show`. Generally returns nothing if link and parent are not specified. If the returned error is [ErrDumpInterrupted], results may be inconsistent or incomplete.

(link Link, parent uint32)

// If the returned error is [ErrDumpInterrupted], results may be inconsistent
// or incomplete.
func (h *Handle) ClassList(link Link, parent uint32) ([]Class, error) {
	req := h.newNetlinkRequest(unix.RTM_GETTCLASS, unix.NLM_F_DUMP)
	msg := &nl.TcMsg{
		Family: nl.FAMILY_ALL,
		Parent: parent,
	}
	if link != nil {
		base := link.Attrs()
		h.ensureIndex(base)
		msg.Ifindex = int32(base.Index)
	}
	req.AddData(msg)

	msgs, executeErr := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWTCLASS)
	if executeErr != nil && !errors.Is(executeErr, ErrDumpInterrupted) {
		return nil, executeErr
	}

	var res []Class
	for _, m := range msgs {
		msg := nl.DeserializeTcMsg(m)

		attrs, err := nl.ParseRouteAttr(m[msg.Len():])
		if err != nil {
			return nil, err
		}

		base := ClassAttrs{
			LinkIndex:  int(msg.Ifindex),
			Handle:     msg.Handle,
			Parent:     msg.Parent,
			Statistics: nil,
		}

		var class Class
		classType := ""
		for _, attr := range attrs {
			switch attr.Attr.Type {
			case nl.TCA_KIND:
				classType = string(attr.Value[:len(attr.Value)-1])
				switch classType {
				case "htb":
					class = &HtbClass{}
				case "hfsc":
					class = &HfscClass{}
				default:
					class = &GenericClass{ClassType: classType}
				}
			case nl.TCA_OPTIONS:
				switch classType {
				case "htb":
					data, err := nl.ParseRouteAttr(attr.Value)
					if err != nil {
						return nil, err
					}
					_, err = parseHtbClassData(class, data)
					if err != nil {
						return nil, err