6 files changed, 553 insertions, 0 deletions
diff --git a/src/crc32.rs b/src/crc32.rs
new file mode 100644
index 0000000..6b3f9d7
--- /dev/null
+++ b/src/crc32.rs
@@ -0,0 +1,84 @@
+// https://github.com/d-e-s-o/nitrocli/blob/ac29709a644682c61a5a28d2a23f8887174fcc31/nitrocli/src/crc32.rs
+//
+// *************************************************************************
+// * Copyright (C) 2017 Daniel Mueller (deso@posteo.net)                   *
+// *                                                                       *
+// * This program is free software: you can redistribute it and/or modify  *
+// * it under the terms of the GNU General Public License as published by  *
+// * the Free Software Foundation, either version 3 of the License, or     *
+// * (at your option) any later version.                                   *
+// *                                                                       *
+// * This program is distributed in the hope that it will be useful,       *
+// * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+// * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+// * GNU General Public License for more details.                          *
+// *                                                                       *
+// * You should have received a copy of the GNU General Public License     *
+// * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+// *************************************************************************
+
+/// Polynomial used in STM32.
+const CRC32_POLYNOMIAL: u32 = 0x04c11db7;
+
+fn crc32(mut crc: u32, data: u32) -> u32 {
+    crc = crc ^ data;
+
+    for _ in 0..32 {
+        if crc & 0x80000000 != 0 {
+            crc = (crc << 1) ^ CRC32_POLYNOMIAL;
+        } else {
+            crc = crc << 1;
+        }
+    }
+    return crc;
+}
+
+/// Retrieve a u32 slice of the 'data' part.
+///
+/// Note that the size of the supplied data has to be a multiple of 4
+/// bytes.
+fn as_slice_u32(data: &[u8]) -> &[u32] {
+    assert!(data.len() % ::std::mem::size_of::<u32>() == 0);
+
+    unsafe {
+        let ptr = data.as_ptr() as *const u32;
+        let len = data.len() / ::std::mem::size_of::<u32>();
+        return ::std::slice::from_raw_parts(ptr, len);
+    }
+}
+
+/// Calculate the CRC of a byte slice.
+pub fn crc(data: &[u8]) -> u32 {
+    let mut crc = 0xffffffff;
+
+    for value in as_slice_u32(data) {
+        crc = crc32(crc, *value);
+    }
+
+    return crc;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_crc32() {
+        let mut crc = 0;
+
+        // The expected values were computed with the original function.
+        crc = crc32(crc, 0xdeadbeef);
+        assert_eq!(crc, 0x46dec763);
+
+        crc = crc32(crc, 42);
+        assert_eq!(crc, 0x7e579b45);
+    }
+
+    #[test]
+    fn test_crc() {
+        let data = &"thisisatextthatistobecrced..".to_string().into_bytes();
+        let crc = crc(data);
+
+        assert_eq!(crc, 0x469db4ee);
+    }
+}
diff --git a/src/devices.rs b/src/devices.rs
new file mode 100644
index 0000000..a40207b
--- /dev/null
+++ b/src/devices.rs
@@ -0,0 +1,62 @@
+use crate::features;
+use crate::{Error, Model};
+
+mod pro;
+
+pub use pro::Pro;
+
+#[derive(Debug)]
+pub enum Device {
+    Pro(Pro),
+}
+
+impl Device {
+    fn as_basic(&self) -> &dyn features::Basic {
+        match self {
+            Device::Pro(pro) => pro,
+        }
+    }
+}
+
+impl RawDevice for Device {
+    fn execute<T, U>(&self, command_id: impl Into<u8>, data: T) -> Result<U, Error>
+    where
+        T: serde::Serialize,
+        U: serde::de::DeserializeOwned
+    {
+        match self {
+            Device::Pro(pro) => pro.execute(command_id, data),
+        }
+    }
+}
+
+impl features::Basic for Device {
+    fn get_model(&self) -> Model {
+        self.as_basic().get_model()
+    }
+
+    fn get_status(&self) -> Result<features::Status, Error> {
+        self.as_basic().get_status()
+    }
+
+    fn get_user_retry_count(&self) -> Result<u8, Error> {
+        self.as_basic().get_user_retry_count()
+    }
+
+    fn get_admin_retry_count(&self) -> Result<u8, Error> {
+        self.as_basic().get_admin_retry_count()
+    }
+}
+
+impl From<Pro> for Device {
+    fn from(pro: Pro) -> Device {
+        Device::Pro(pro)
+    }
+}
+
+pub(crate) trait RawDevice {
+    fn execute<T, U>(&self, command_id: impl Into<u8>, data: T) -> Result<U, Error>
+    where
+        T: serde::Serialize,
+        U: serde::de::DeserializeOwned;
+}
diff --git a/src/devices/pro.rs b/src/devices/pro.rs
new file mode 100644
index 0000000..f986f6b
--- /dev/null
+++ b/src/devices/pro.rs
@@ -0,0 +1,99 @@
+use std::fmt;
+
+use crate::{devices, hid, features, DeviceInfo, Error, Model};
+use crate::devices::RawDevice as _;
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[repr(u8)]
+enum Command {
+    GetStatus = 0x00,
+    GetPasswordRetryCount = 0x09,
+    GetUserPasswordRetryCount = 0x0F,
+}
+
+impl From<Command> for u8 {
+    fn from(command: Command) -> u8 {
+        command as u8
+    }
+}
+
+pub struct Pro {
+    hid_device: hidapi::HidDevice,
+    path: std::ffi::CString,
+}
+
+impl Pro {
+    pub(crate) fn new(hid_device: hidapi::HidDevice, device_info: &DeviceInfo<'_>) -> Self {
+        Self {
+            hid_device,
+            path: device_info.device_info.path().to_owned(),
+        }
+    }
+}
+
+impl features::Basic for Pro {
+    fn get_model(&self) -> Model {
+        Model::Pro
+    }
+
+    fn get_status(&self) -> Result<features::Status, Error> {
+        self.execute(Command::GetStatus, ())
+    }
+
+    fn get_user_retry_count(&self) -> Result<u8, Error> {
+        self.execute(Command::GetPasswordRetryCount, ())
+    }
+
+    fn get_admin_retry_count(&self) -> Result<u8, Error> {
+        self.execute(Command::GetUserPasswordRetryCount, ())
+    }
+}
+
+impl devices::RawDevice for Pro {
+    fn execute<T, U>(&self, command_id: impl Into<u8>, data: T) -> Result<U, Error>
+    where
+        T: serde::Serialize,
+        U: serde::de::DeserializeOwned,
+    {
+        use hid::HidDeviceExt as _;
+
+        let command_id = command_id.into();
+        let crc = self.hid_device.send(&hid::Request::new(command_id, data))?;
+
+        let mut response = self.hid_device.receive()?;
+        let mut retry_count = 0;
+        while response.device_status == hid::DeviceStatus::Busy && retry_count < 3 {
+            std::thread::sleep(std::time::Duration::from_millis(100));
+            response = self.hid_device.receive()?;
+            retry_count += 1;
+        }
+
+        if response.device_status != hid::DeviceStatus::Ok {
+            return Err(format!("Got device status {:?}", response.device_status).into());
+        }
+        if response.command_id != command_id {
+            return Err(format!(
+                "Expected command ID {}, got {}",
+                command_id, response.command_id
+            )
+            .into());
+        }
+        if response.command_status != hid::CommandStatus::Ok {
+            return Err(format!("Got command status {:?}", response.command_status).into());
+        }
+        if response.last_crc() != crc {
+            return Err(format!("Expected last_crc {}, got {}", crc, response.last_crc()).into());
+        }
+
+        Ok(response.data)
+    }
+}
+
+impl fmt::Debug for Pro {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Pro")
+            .field("path", &self.path)
+            .finish()
+    }
+}
+
diff --git a/src/features.rs b/src/features.rs
new file mode 100644
index 0000000..1ec5dff
--- /dev/null
+++ b/src/features.rs
@@ -0,0 +1,20 @@
+use crate::{Error, Model};
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Deserialize)]
+pub struct Status {
+    pub firmware_version_minor: u8,
+    pub firmware_version_major: u8,
+    pub serial_number: u32,
+    pub config_num_lock: u8,
+    pub config_caps_lock: u8,
+    pub config_scroll_lock: u8,
+    pub config_enable_user_password: u8,
+    _unused: u8,
+}
+
+pub trait Basic {
+    fn get_model(&self) -> Model;
+    fn get_status(&self) -> Result<Status, Error>;
+    fn get_user_retry_count(&self) -> Result<u8, Error>;
+    fn get_admin_retry_count(&self) -> Result<u8, Error>;
+}
diff --git a/src/hid.rs b/src/hid.rs
new file mode 100644
index 0000000..291216c
--- /dev/null
+++ b/src/hid.rs
@@ -0,0 +1,187 @@
+use std::convert;
+use std::convert::TryFrom as _;
+
+use crate::crc32;
+use crate::Error;
+
+pub const REPORT_LEN: usize = 65;
+pub const REPORT_PAYLOAD_LEN: usize = REPORT_LEN - 5;
+pub const MAX_REQUEST_DATA_LEN: usize = REPORT_PAYLOAD_LEN - 1;
+pub const MAX_RESPONSE_DATA_LEN: usize = REPORT_PAYLOAD_LEN - 7;
+
+serde_big_array::big_array! { BigArray; REPORT_PAYLOAD_LEN }
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
+struct Report {
+    report_id: u8,
+    #[serde(with = "BigArray")]
+    payload: [u8; REPORT_PAYLOAD_LEN],
+    crc: [u8; 4],
+}
+
+static_assertions::assert_eq_size!([u8; REPORT_LEN], Report);
+
+impl Report {
+    fn new(report_id: u8, payload: [u8; REPORT_PAYLOAD_LEN]) -> Report {
+        let crc = crc32::crc(&payload);
+        Report {
+            report_id,
+            payload,
+            crc: crc.to_le_bytes(),
+        }
+    }
+
+    fn from_bytes(data: [u8; REPORT_LEN]) -> Result<Report, Error> {
+        let (report, num_bytes): (Report, _) = ssmarshal::deserialize(&data)?;
+        if num_bytes != REPORT_LEN {
+            return Err(format!("Only {} of {} report bytes read", num_bytes, REPORT_LEN).into());
+        }
+        Ok(report)
+    }
+
+    fn to_bytes(&self) -> Result<[u8; REPORT_LEN], Error> {
+        let mut buf = [0; REPORT_LEN];
+        let num_bytes = ssmarshal::serialize(&mut buf, self)?;
+        if num_bytes != REPORT_LEN {
+            return Err(format!("Invalid report length: {}", num_bytes).into());
+        }
+        Ok(buf)
+    }
+
+    fn crc(&self) -> u32 {
+        u32::from_le_bytes(self.crc)
+    }
+
+    pub fn check_crc(&self) -> Result<(), Error> {
+        let crc = crc32::crc(&self.payload);
+        if self.crc() != crc {
+            Err(format!(
+                "Warning: Report has wrong CRC: got {:x}, expected {:x}",
+                self.crc(),
+                crc
+            )
+            .into())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+impl Default for Report {
+    fn default() -> Report {
+        Report::new(0, [0; REPORT_PAYLOAD_LEN])
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize)]
+pub struct Request<T> {
+    pub command_id: u8,
+    pub data: T,
+}
+
+static_assertions::assert_eq_size!([u8; REPORT_PAYLOAD_LEN - MAX_REQUEST_DATA_LEN], Request<()>,);
+
+impl<T: serde::Serialize> Request<T> {
+    pub fn new(command_id: u8, data: T) -> Request<T> {
+        Request { command_id, data }
+    }
+}
+
+impl<'a, T: serde::Serialize> convert::TryFrom<&'a Request<T>> for Report {
+    type Error = Error;
+
+    fn try_from(request: &'a Request<T>) -> Result<Report, Error> {
+        let mut payload = [0; REPORT_PAYLOAD_LEN];
+        let num_bytes = ssmarshal::serialize(&mut payload, &request)?;
+        if num_bytes > REPORT_PAYLOAD_LEN {
+            return Err(format!("Invalid request length: {}", num_bytes).into());
+        }
+        Ok(Report::new(0, payload))
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Deserialize)]
+#[repr(u8)]
+pub enum DeviceStatus {
+    Ok,
+    Busy,
+    Error,
+    ReceivedReport,
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Deserialize)]
+#[repr(u8)]
+pub enum CommandStatus {
+    Ok,
+    WrongCrc,
+    WrongSlot,
+    SlotNotProgrammed,
+    WrongPassword,
+    NotAuthorized,
+    TimestampWarning,
+    NoNameError,
+    NotSupported,
+    UnknownCommand,
+    AesDecFailed,
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, serde::Deserialize)]
+pub struct Response<T> {
+    pub device_status: DeviceStatus,
+    pub command_id: u8,
+    pub last_crc: [u8; 4],
+    pub command_status: CommandStatus,
+    pub data: T,
+}
+
+static_assertions::assert_eq_size!(
+    [u8; REPORT_PAYLOAD_LEN - MAX_RESPONSE_DATA_LEN],
+    Response<()>,
+);
+
+impl<T: serde::de::DeserializeOwned> Response<T> {
+    pub fn last_crc(&self) -> u32 {
+        u32::from_le_bytes(self.last_crc)
+    }
+}
+
+impl<'a, T: serde::de::DeserializeOwned> convert::TryFrom<&'a Report> for Response<T> {
+    type Error = Error;
+
+    fn try_from(report: &'a Report) -> Result<Response<T>, Error> {
+        let (response, _) = ssmarshal::deserialize(&report.payload)?;
+        Ok(response)
+    }
+}
+
+pub trait HidDeviceExt {
+    fn send<T: serde::Serialize>(&self, request: &Request<T>) -> Result<u32, Error>;
+    fn receive<T: serde::de::DeserializeOwned>(&self) -> Result<Response<T>, Error>;
+}
+
+impl HidDeviceExt for hidapi::HidDevice {
+    fn send<T: serde::Serialize>(&self, request: &Request<T>) -> Result<u32, Error> {
+        let report = Report::try_from(request)?;
+        let data = report.to_bytes()?;
+        self.send_feature_report(&data)?;
+        Ok(report.crc())
+    }
+
+    fn receive<T: serde::de::DeserializeOwned>(&self) -> Result<Response<T>, Error> {
+        let mut buf = [0; REPORT_LEN];
+        let n = self.get_feature_report(&mut buf)?;
+        if n != REPORT_LEN {
+            return Err(format!("Invalid report length: {}", n).into());
+        }
+        let report = Report::from_bytes(buf)?;
+        if report.report_id != 0 {
+            return Err(format!("Invalid report ID: {}", report.report_id).into());
+        }
+        let response = Response::try_from(&report)?;
+        // TODO: is the CRC set for all other status variants?
+        if response.device_status != DeviceStatus::Busy {
+            report.check_crc()?;
+        }
+        Ok(response)
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..a26f02f
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,101 @@
+mod crc32;
+mod hid;
+
+pub mod devices;
+pub mod features;
+
+use std::fmt;
+
+pub type Error = Box<dyn std::error::Error>;
+
+const VID_NITROKEY: u16 = 0x20a0;
+const PID_NITROKEY_PRO: u16 = 0x4108;
+const PID_NITROKEY_STORAGE: u16 = 0x4109;
+
+pub fn connect() -> Result<devices::Device, Error> {
+    let manager = Manager::new()?;
+    if let Some(device) = manager.devices().first() {
+        device.connect()
+    } else {
+        Err("No device connected".into())
+    }
+}
+
+pub fn connect_model(model: Model) -> Result<devices::Device, Error> {
+    let manager = Manager::new()?;
+    if let Some(device) = manager.devices().iter().filter(|i| i.model == model).next() {
+        device.connect()
+    } else {
+        Err(format!("No {:?} device connected", model).into())
+    }
+}
+
+pub struct Manager {
+    hidapi: hidapi::HidApi,
+}
+
+impl Manager {
+    pub fn new() -> Result<Self, Error> {
+        let hidapi = hidapi::HidApi::new()?;
+        Ok(Manager { hidapi })
+    }
+
+    pub fn devices(&self) -> Vec<DeviceInfo<'_>> {
+        self.hidapi
+            .device_list()
+            .flat_map(|device_info| {
+                Model::from_vid_pid(device_info.vendor_id(), device_info.product_id()).map(
+                    |model| DeviceInfo {
+                        hidapi: &self.hidapi,
+                        device_info,
+                        model,
+                    },
+                )
+            })
+            .collect()
+    }
+}
+
+#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub enum Model {
+    Pro,
+    Storage,
+}
+
+impl Model {
+    fn from_vid_pid(vid: u16, pid: u16) -> Option<Model> {
+        match vid {
+            VID_NITROKEY => match pid {
+                PID_NITROKEY_PRO => Some(Model::Pro),
+                PID_NITROKEY_STORAGE => Some(Model::Storage),
+                _ => None,
+            },
+            _ => None,
+        }
+    }
+}
+
+pub struct DeviceInfo<'a> {
+    hidapi: &'a hidapi::HidApi,
+    device_info: &'a hidapi::DeviceInfo,
+    model: Model,
+}
+
+impl<'a> DeviceInfo<'a> {
+    pub fn connect(&self) -> Result<devices::Device, Error> {
+        let hid_device = self.device_info.open_device(self.hidapi)?;
+        match self.model {
+            Model::Pro => Ok(devices::Pro::new(hid_device, self).into()),
+            Model::Storage => unimplemented!(),
+        }
+    }
+}
+
+impl<'a> fmt::Debug for DeviceInfo<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("DeviceInfo")
+            .field("model", &self.model)
+            .field("path", &self.device_info.path())
+            .finish()
+    }
+}