Update dependencies

vendor/github.com/mdlayher/genetlink/family_linux.go

@@ -0,0 +1,150 @@
+//go:build linux
+// +build linux
+
+package genetlink
+
+import (
+	"errors"
+	"fmt"
+	"math"
+
+	"github.com/mdlayher/netlink"
+	"github.com/mdlayher/netlink/nlenc"
+	"golang.org/x/sys/unix"
+)
+
+// errInvalidFamilyVersion is returned when a family's version is greater
+// than an 8-bit integer.
+var errInvalidFamilyVersion = errors.New("invalid family version attribute")
+
+// getFamily retrieves a generic netlink family with the specified name.
+func (c *Conn) getFamily(name string) (Family, error) {
+	b, err := netlink.MarshalAttributes([]netlink.Attribute{{
+		Type: unix.CTRL_ATTR_FAMILY_NAME,
+		Data: nlenc.Bytes(name),
+	}})
+	if err != nil {
+		return Family{}, err
+	}
+
+	req := Message{
+		Header: Header{
+			Command: unix.CTRL_CMD_GETFAMILY,
+			// TODO(mdlayher): grab nlctrl version?
+			Version: 1,
+		},
+		Data: b,
+	}
+
+	msgs, err := c.Execute(req, unix.GENL_ID_CTRL, netlink.Request)
+	if err != nil {
+		return Family{}, err
+	}
+
+	// TODO(mdlayher): consider interpreting generic netlink header values
+
+	families, err := buildFamilies(msgs)
+	if err != nil {
+		return Family{}, err
+	}
+	if len(families) != 1 {
+		// If this were to ever happen, netlink must be in a state where
+		// its answers cannot be trusted
+		panic(fmt.Sprintf("netlink returned multiple families for name: %q", name))
+	}
+
+	return families[0], nil
+}
+
+// listFamilies retrieves all registered generic netlink families.
+func (c *Conn) listFamilies() ([]Family, error) {
+	req := Message{
+		Header: Header{
+			Command: unix.CTRL_CMD_GETFAMILY,
+			// TODO(mdlayher): grab nlctrl version?
+			Version: 1,
+		},
+	}
+
+	msgs, err := c.Execute(req, unix.GENL_ID_CTRL, netlink.Request|netlink.Dump)
+	if err != nil {
+		return nil, err
+	}
+
+	return buildFamilies(msgs)
+}
+
+// buildFamilies builds a slice of Families by parsing attributes from the
+// input Messages.
+func buildFamilies(msgs []Message) ([]Family, error) {
+	families := make([]Family, 0, len(msgs))
+	for _, m := range msgs {
+		f, err := parseFamily(m.Data)
+		if err != nil {
+			return nil, err
+		}
+
+		families = append(families, f)
+	}
+
+	return families, nil
+}
+
+// parseFamily decodes netlink attributes into a Family.
+func parseFamily(b []byte) (Family, error) {
+	ad, err := netlink.NewAttributeDecoder(b)
+	if err != nil {
+		return Family{}, err
+	}
+
+	var f Family
+	for ad.Next() {
+		switch ad.Type() {
+		case unix.CTRL_ATTR_FAMILY_ID:
+			f.ID = ad.Uint16()
+		case unix.CTRL_ATTR_FAMILY_NAME:
+			f.Name = ad.String()
+		case unix.CTRL_ATTR_VERSION:
+			v := ad.Uint32()
+			if v > math.MaxUint8 {
+				return Family{}, errInvalidFamilyVersion
+			}
+
+			f.Version = uint8(v)
+		case unix.CTRL_ATTR_MCAST_GROUPS:
+			ad.Nested(parseMulticastGroups(&f.Groups))
+		}
+	}
+
+	if err := ad.Err(); err != nil {
+		return Family{}, err
+	}
+
+	return f, nil
+}
+
+// parseMulticastGroups parses an array of multicast group nested attributes
+// into a slice of MulticastGroups.
+func parseMulticastGroups(groups *[]MulticastGroup) func(*netlink.AttributeDecoder) error {
+	return func(ad *netlink.AttributeDecoder) error {
+		*groups = make([]MulticastGroup, 0, ad.Len())
+		for ad.Next() {
+			ad.Nested(func(nad *netlink.AttributeDecoder) error {
+				var g MulticastGroup
+				for nad.Next() {
+					switch nad.Type() {
+					case unix.CTRL_ATTR_MCAST_GRP_NAME:
+						g.Name = nad.String()
+					case unix.CTRL_ATTR_MCAST_GRP_ID:
+						g.ID = nad.Uint32()
+					}
+				}
+
+				*groups = append(*groups, g)
+				return nil
+			})
+		}
+
+		return nil
+	}
+}