Revert vendor directory to support old golang (GOPATH mode)

gomodule is still in progress to migrate for now, hence multus
team decide to keep vendor directory to support build without
gomodule.

vendor/github.com/vishvananda/netlink/nl/genetlink_linux.go

@@ -0,0 +1,89 @@
+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
+)
+
+const (
+	GENL_GTP_VERSION = 0
+	GENL_GTP_NAME    = "gtp"
+)
+
+const (
+	GENL_GTP_CMD_NEWPDP = iota
+	GENL_GTP_CMD_DELPDP
+	GENL_GTP_CMD_GETPDP
+)
+
+const (
+	GENL_GTP_ATTR_UNSPEC = iota
+	GENL_GTP_ATTR_LINK
+	GENL_GTP_ATTR_VERSION
+	GENL_GTP_ATTR_TID
+	GENL_GTP_ATTR_PEER_ADDRESS
+	GENL_GTP_ATTR_MS_ADDRESS
+	GENL_GTP_ATTR_FLOW
+	GENL_GTP_ATTR_NET_NS_FD
+	GENL_GTP_ATTR_I_TEI
+	GENL_GTP_ATTR_O_TEI
+	GENL_GTP_ATTR_PAD
+)
+
+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)))[:]
+}