static int vvalue_tvb_blob(tvbuff_t *tvb, int offset, void *val)
{
	struct data_blob *blob = (struct data_blob*)val;
	guint32 len = tvb_get_letohl(tvb, offset);

	blob->size = len;
	blob->data = (guint8*)tvb_memdup(wmem_packet_scope(), tvb, offset + 4, len);

	return 4 + len;
}
static int vvalue_tvb_blob(tvbuff_t *tvb, int offset, void *val)
{
	struct data_blob *blob = (struct data_blob*)val;
	guint32 len = tvb_get_letohl(tvb, offset);

	blob->size = len;
	blob->data = (guint8*)tvb_memdup(wmem_packet_scope(), tvb, offset + 4, len);

	return 4 + len;
}