checkpt

overlay/vhostnet/ioctl.go

@@ -0,0 +1,31 @@
+package vhostnet
+
+import (
+	"fmt"
+	"unsafe"
+
+	"github.com/hetznercloud/virtio-go/vhost"
+)
+
+const (
+	// vhostNetIoctlSetBackend can be used to attach a virtqueue to a RAW socket
+	// or TAP device.
+	//
+	// Request payload: [vhost.QueueFile]
+	// Kernel name: VHOST_NET_SET_BACKEND
+	vhostNetIoctlSetBackend = 0x4008af30
+)
+
+// SetQueueBackend attaches a virtqueue of the vhost networking device
+// described by controlFD to the given backend file descriptor.
+// The backend file descriptor can either be a RAW socket or a TAP device. When
+// it is -1, the queue will be detached.
+func SetQueueBackend(controlFD int, queueIndex uint32, backendFD int) error {
+	if err := vhost.IoctlPtr(controlFD, vhostNetIoctlSetBackend, unsafe.Pointer(&vhost.QueueFile{
+		QueueIndex: queueIndex,
+		FD:         int32(backendFD),
+	})); err != nil {
+		return fmt.Errorf("set queue backend file descriptor: %w", err)
+	}
+	return nil
+}