Add support for generic netlink

Signed-off-by: Wataru Ishida <ishida.wataru@lab.ntt.co.jp>

genetlink_linux.go

@@ -0,0 +1,167 @@
+package netlink
+
+import (
+	"fmt"
+	"syscall"
+
+	"github.com/vishvananda/netlink/nl"
+)
+
+type GenlOp struct {
+	ID    uint32
+	Flags uint32
+}
+
+type GenlMulticastGroup struct {
+	ID   uint32
+	Name string
+}
+
+type GenlFamily struct {
+	ID      uint16
+	HdrSize uint32
+	Name    string
+	Version uint32
+	MaxAttr uint32
+	Ops     []GenlOp
+	Groups  []GenlMulticastGroup
+}
+
+func parseOps(b []byte) ([]GenlOp, error) {
+	attrs, err := nl.ParseRouteAttr(b)
+	if err != nil {
+		return nil, err
+	}
+	ops := make([]GenlOp, 0, len(attrs))
+	for _, a := range attrs {
+		nattrs, err := nl.ParseRouteAttr(a.Value)
+		if err != nil {
+			return nil, err
+		}
+		var op GenlOp
+		for _, na := range nattrs {
+			switch na.Attr.Type {
+			case nl.GENL_CTRL_ATTR_OP_ID:
+				op.ID = native.Uint32(na.Value)
+			case nl.GENL_CTRL_ATTR_OP_FLAGS:
+				op.Flags = native.Uint32(na.Value)
+			}
+		}
+		ops = append(ops, op)
+	}
+	return ops, nil
+}
+
+func parseMulticastGroups(b []byte) ([]GenlMulticastGroup, error) {
+	attrs, err := nl.ParseRouteAttr(b)
+	if err != nil {
+		return nil, err
+	}
+	groups := make([]GenlMulticastGroup, 0, len(attrs))
+	for _, a := range attrs {
+		nattrs, err := nl.ParseRouteAttr(a.Value)
+		if err != nil {
+			return nil, err
+		}
+		var g GenlMulticastGroup
+		for _, na := range nattrs {
+			switch na.Attr.Type {
+			case nl.GENL_CTRL_ATTR_MCAST_GRP_NAME:
+				g.Name = nl.BytesToString(na.Value)
+			case nl.GENL_CTRL_ATTR_MCAST_GRP_ID:
+				g.ID = native.Uint32(na.Value)
+			}
+		}
+		groups = append(groups, g)
+	}
+	return groups, nil
+}
+
+func (f *GenlFamily) parseAttributes(attrs []syscall.NetlinkRouteAttr) error {
+	for _, a := range attrs {
+		switch a.Attr.Type {
+		case nl.GENL_CTRL_ATTR_FAMILY_NAME:
+			f.Name = nl.BytesToString(a.Value)
+		case nl.GENL_CTRL_ATTR_FAMILY_ID:
+			f.ID = native.Uint16(a.Value)
+		case nl.GENL_CTRL_ATTR_VERSION:
+			f.Version = native.Uint32(a.Value)
+		case nl.GENL_CTRL_ATTR_HDRSIZE:
+			f.HdrSize = native.Uint32(a.Value)
+		case nl.GENL_CTRL_ATTR_MAXATTR:
+			f.MaxAttr = native.Uint32(a.Value)
+		case nl.GENL_CTRL_ATTR_OPS:
+			ops, err := parseOps(a.Value)
+			if err != nil {
+				return err
+			}
+			f.Ops = ops
+		case nl.GENL_CTRL_ATTR_MCAST_GROUPS:
+			groups, err := parseMulticastGroups(a.Value)
+			if err != nil {
+				return err
+			}
+			f.Groups = groups
+		}
+	}
+
+	return nil
+}
+
+func parseFamilies(msgs [][]byte) ([]*GenlFamily, error) {
+	families := make([]*GenlFamily, 0, len(msgs))
+	for _, m := range msgs {
+		attrs, err := nl.ParseRouteAttr(m[nl.SizeofGenlmsg:])
+		if err != nil {
+			return nil, err
+		}
+		family := &GenlFamily{}
+		if err := family.parseAttributes(attrs); err != nil {
+			return nil, err
+		}
+
+		families = append(families, family)
+	}
+	return families, nil
+}
+
+func (h *Handle) GenlFamilyList() ([]*GenlFamily, error) {
+	msg := &nl.Genlmsg{
+		Command: nl.GENL_CTRL_CMD_GETFAMILY,
+		Version: nl.GENL_CTRL_VERSION,
+	}
+	req := h.newNetlinkRequest(nl.GENL_ID_CTRL, syscall.NLM_F_DUMP)
+	req.AddData(msg)
+	msgs, err := req.Execute(syscall.NETLINK_GENERIC, 0)
+	if err != nil {
+		return nil, err
+	}
+	return parseFamilies(msgs)
+}
+
+func GenlFamilyList() ([]*GenlFamily, error) {
+	return pkgHandle.GenlFamilyList()
+}
+
+func (h *Handle) GenlFamilyGet(name string) (*GenlFamily, error) {
+	msg := &nl.Genlmsg{
+		Command: nl.GENL_CTRL_CMD_GETFAMILY,
+		Version: nl.GENL_CTRL_VERSION,
+	}
+	req := h.newNetlinkRequest(nl.GENL_ID_CTRL, 0)
+	req.AddData(msg)
+	req.AddData(nl.NewRtAttr(nl.GENL_CTRL_ATTR_FAMILY_NAME, nl.ZeroTerminated(name)))
+	msgs, err := req.Execute(syscall.NETLINK_GENERIC, 0)
+	if err != nil {
+		return nil, err
+	}
+	families, err := parseFamilies(msgs)
+	if len(families) != 1 {
+		return nil, fmt.Errorf("invalid response for GENL_CTRL_CMD_GETFAMILY")
+	}
+	return families[0], nil
+}
+
+func GenlFamilyGet(name string) (*GenlFamily, error) {
+	return pkgHandle.GenlFamilyGet(name)
+}

genetlink_unspecified.go

@@ -0,0 +1,25 @@
+// +build !linux
+
+package netlink
+
+type GenlOp struct{}
+
+type GenlMulticastGroup struct{}
+
+type GenlFamily struct{}
+
+func (h *Handle) GenlFamilyList() ([]*GenlFamily, error) {
+	return nil, ErrNotImplemented
+}
+
+func GenlFamilyList() ([]*GenlFamily, error) {
+	return nil, ErrNotImplemented
+}
+
+func (h *Handle) GenlFamilyGet(name string) (*GenlFamily, error) {
+	return nil, ErrNotImplemented
+}
+
+func GenlFamilyGet(name string) (*GenlFamily, error) {
+	return nil, ErrNotImplemented
+}

nl/genetlink_linux.go

@@ -0,0 +1,64 @@
+package nl
+
+import (
+	"unsafe"
+)
+
+const SizeofGenlmsg = 4
+
+const (
+	GENL_ID_CTRL      = 0x10
+	GENL_CTRL_VERSION = 2
+	GENL_CTRL_NAME    = "nlctrl"
+)
+
+const (
+	GENL_CTRL_CMD_GETFAMILY = 3
+)
+
+const (
+	GENL_CTRL_ATTR_UNSPEC = iota
+	GENL_CTRL_ATTR_FAMILY_ID
+	GENL_CTRL_ATTR_FAMILY_NAME
+	GENL_CTRL_ATTR_VERSION
+	GENL_CTRL_ATTR_HDRSIZE
+	GENL_CTRL_ATTR_MAXATTR
+	GENL_CTRL_ATTR_OPS
+	GENL_CTRL_ATTR_MCAST_GROUPS
+)
+
+const (
+	GENL_CTRL_ATTR_OP_UNSPEC = iota
+	GENL_CTRL_ATTR_OP_ID
+	GENL_CTRL_ATTR_OP_FLAGS
+)
+
+const (
+	GENL_ADMIN_PERM = 1 << iota
+	GENL_CMD_CAP_DO
+	GENL_CMD_CAP_DUMP
+	GENL_CMD_CAP_HASPOL
+)
+
+const (
+	GENL_CTRL_ATTR_MCAST_GRP_UNSPEC = iota
+	GENL_CTRL_ATTR_MCAST_GRP_NAME
+	GENL_CTRL_ATTR_MCAST_GRP_ID
+)
+
+type Genlmsg struct {
+	Command uint8
+	Version uint8
+}
+
+func (msg *Genlmsg) Len() int {
+	return SizeofGenlmsg
+}
+
+func DeserializeGenlmsg(b []byte) *Genlmsg {
+	return (*Genlmsg)(unsafe.Pointer(&b[0:SizeofGenlmsg][0]))
+}
+
+func (msg *Genlmsg) Serialize() []byte {
+	return (*(*[SizeofGenlmsg]byte)(unsafe.Pointer(msg)))[:]
+}