commit 9ed8a6fd9f80b008909548cb139420ed8dc34de0
Author: Nicolas Stalder <n@stalder.io>
Date:   Sat May 2 04:14:46 2020 +0200

    Basics for CCID from Zissou (ATR)

diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..7d4e774
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,18 @@
+[package]
+name = "usbd-ccid"
+version = "0.0.0-unreleased"
+authors = ["Nicolas Stalder <n@stalder.io>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+cortex-m-semihosting = { version = "0.3.5", optional = true}
+usb-device = { version = "0.2.3", features = ["control-buffer-256"] }
+
+[features]
+default = [
+  "cortex-m-semihosting",
+]
+highspeed-usb = []
+
diff --git a/src/class.rs b/src/class.rs
new file mode 100644
index 0000000..da04270
--- /dev/null
+++ b/src/class.rs
@@ -0,0 +1,130 @@
+use core::convert::TryFrom;
+
+use cortex_m_semihosting::hprintln;
+
+use crate::{
+    constants::*,
+    pipe::Pipe,
+};
+
+use usb_device::class_prelude::*;
+
+type Result<T> = core::result::Result<T, UsbError>;
+
+pub struct Ccid<Bus>
+where
+    Bus: 'static + UsbBus,
+{
+    interface_number: InterfaceNumber,
+    pipe: Pipe<Bus>,
+    must_send_zlp: bool,
+}
+
+impl<Bus> Ccid<Bus>
+where
+    Bus: 'static + UsbBus,
+{
+    pub fn new(allocator: &'static UsbBusAllocator<Bus>) -> Self {
+        let read_endpoint = allocator.bulk(PACKET_SIZE as _);
+        let write_endpoint = allocator.bulk(PACKET_SIZE as _);
+        let pipe = Pipe::new(read_endpoint, write_endpoint);
+        let interface_number = allocator.interface();
+        Self { interface_number, pipe, must_send_zlp: false }
+    }
+}
+
+pub enum ClassRequests {
+}
+
+impl<Bus> UsbClass<Bus> for Ccid<Bus>
+where
+    Bus: 'static + UsbBus,
+{
+    fn get_configuration_descriptors(&self, writer: &mut DescriptorWriter)
+        -> Result<()>
+    {
+        writer.interface(
+            self.interface_number,
+            CLASS_CCID,
+            SUBCLASS_NONE,
+            TransferMode::Bulk as u8,
+        )?;
+        writer.write(
+            FUNCTIONAL_INTERFACE,
+            &FUNCTIONAL_INTERFACE_DESCRIPTOR,
+        )?;
+        writer.endpoint(&self.pipe.write);
+        writer.endpoint(&self.pipe.read);
+        Ok(())
+    }
+
+    fn poll(&mut self) {
+        self.pipe.maybe_write_packet();
+    }
+
+    fn endpoint_in_complete(&mut self, addr: EndpointAddress) {
+        if addr != self.pipe.write.address() { return; }
+
+        if self.must_send_zlp {
+            self.pipe.write.write(&[]).ok();
+            self.must_send_zlp = false;
+        } else {
+            self.pipe.maybe_write_packet();
+        }
+    }
+
+    fn endpoint_out(&mut self, addr: EndpointAddress) {
+        if addr != self.pipe.read.address() { return; }
+
+        self.pipe.read_and_handle_packet();
+    }
+
+    fn control_in(&mut self, transfer: ControlIn<Bus>) {
+        use usb_device::control::*;
+
+        let Request { request_type, recipient, index, request, .. } = *transfer.request();
+
+        if index as u8 != u8::from(self.interface_number) {
+            return;
+        }
+
+        if (request_type, recipient) == (RequestType::Class, Recipient::Interface) {
+            match ClassRequest::try_from(request) {
+                Ok(request) => {
+                    match request {
+                        ClassRequest::Abort => {
+                            // oh yeah?
+                            transfer.reject().ok();
+                            todo!();
+                        }
+
+                        // not strictly needed, as our bNumClockSupported = 0
+                        ClassRequest::GetClockFrequencies => {
+                            transfer.accept(|data| {
+                                data.copy_from_slice(&CLOCK_FREQUENCY_KHZ);
+                                Ok(4)
+                            }).ok();
+                        },
+
+                        // not strictly needed, as our bNumDataRatesSupported = 0
+                        ClassRequest::GetDataRates => {
+                            transfer.accept(|data| {
+                                data.copy_from_slice(&DATA_RATE_BPS);
+                                Ok(4)
+                            }).ok();
+                        },
+                    }
+                }
+
+                Err(()) => {
+                    hprintln!("unexpected request: {}", request).ok();
+                }
+            }
+        }
+    }
+
+    fn control_out(&mut self, transfer: ControlOut<Bus>) {
+        // todo!();
+    }
+
+}
diff --git a/src/constants.rs b/src/constants.rs
new file mode 100644
index 0000000..be1c1b0
--- /dev/null
+++ b/src/constants.rs
@@ -0,0 +1,137 @@
+// can be 8, 16, 32, 64 or 512
+#[cfg(feature = "highspeed-usb")]
+pub const PACKET_SIZE: usize = 512;
+#[cfg(not(feature = "highspeed-usb"))]
+pub const PACKET_SIZE: usize = 64;
+
+pub const CLASS_CCID: u8 = 0x0B;
+pub const SUBCLASS_NONE: u8 = 0x0;
+
+#[repr(u8)]
+pub enum TransferMode {
+    // bulk transfers, optional interrupt IN
+    Bulk = 0,
+    // control transfers, no interrupt IN
+    ControlA = 1,
+    // control transfers, optional interrupt IN
+    ControlB = 2,
+}
+
+pub const FUNCTIONAL_INTERFACE: u8 = 0x21;
+
+pub enum ClassRequest {
+    Abort = 1,
+    GetClockFrequencies = 2,
+    GetDataRates = 3,
+}
+
+impl core::convert::TryFrom<u8> for ClassRequest {
+    type Error = ();
+    fn try_from(request: u8) -> core::result::Result<Self, ()> {
+        Ok(match request {
+            1 => Self::Abort,
+            2 => Self::GetClockFrequencies,
+            3 => Self::GetDataRates,
+            _ => return Err(()),
+        })
+    }
+}
+
+// NB: all numbers are little-endian
+
+// 4000 KHz = 4MHz
+// pub const CLOCK_FREQUENCY: [u8; 4] = 4000u32.to_le_bytes();
+// instead, use Python: `import struct; struct.pack("<I", 4000)`
+pub const CLOCK_FREQUENCY_KHZ: [u8; 4] = [0xa0, 0x0f, 0x00, 0x00];
+// 307200 bps (gnuk: 9600)
+pub const DATA_RATE_BPS: [u8; 4] = [0x00, 0xb0, 0x04, 0x00];
+// 2038 (gnuk: 254)
+pub const MAX_IFSD: [u8; 4] = [0xf6, 0x07, 0x00, 0x00];
+
+//
+// dwMaxCCIDMsgLen 3072 (gnuk: 271)
+pub const MAX_MSG_LENGTH: usize = 3072;
+pub const MAX_MSG_LENGTH_LE: [u8; 4] = [0x00, 0x0C, 0x00, 0x00];
+pub const NUM_SLOTS: u8 = 1;
+pub const MAX_BUSY_SLOTS: u8 = 1;
+// bPinSupport (0x0 = none, 0x01 = verification, 0x02 = modification)
+pub const PIN_SUPPORT: u8 = 0;
+
+// cf. Sec. 5.1 in: https://www.usb.org/sites/default/files/DWG_Smart-Card_CCID_Rev110.pdf
+pub const FUNCTIONAL_INTERFACE_DESCRIPTOR: [u8; 52] = [
+    // bcdCCID rev1.10 <-- Linux doesn't know about this
+    // 0x10, 0x01,
+
+    // bcdCCID rev1.00
+    0x00, 0x01,
+    // bMaxSlotIndex
+    NUM_SLOTS - 1,
+    // bVoltageSupport (5.0V + 3.0V + 1.8V)
+    0x07,
+    // dwProtocols: T=1 only (0 = T=0, 3 = T0+T1)
+    0x02, 0x00, 0x00, 0x00,
+
+    // dwDefaultClock (4 MHz)
+    CLOCK_FREQUENCY_KHZ[0],
+    CLOCK_FREQUENCY_KHZ[1],
+    CLOCK_FREQUENCY_KHZ[2],
+    CLOCK_FREQUENCY_KHZ[3],
+    // dwMaximumClock (same)
+    CLOCK_FREQUENCY_KHZ[0],
+    CLOCK_FREQUENCY_KHZ[1],
+    CLOCK_FREQUENCY_KHZ[2],
+    CLOCK_FREQUENCY_KHZ[3],
+    // bNumClockSupported
+    0x00,
+
+    // dwDataRate (307200 bps)
+    DATA_RATE_BPS[0],
+    DATA_RATE_BPS[1],
+    DATA_RATE_BPS[2],
+    DATA_RATE_BPS[3],
+    // dwMaxDataRate (same)
+    DATA_RATE_BPS[0],
+    DATA_RATE_BPS[1],
+    DATA_RATE_BPS[2],
+    DATA_RATE_BPS[3],
+    // bNumDataRatesSupported
+    0x00,
+
+    // dwMaxIFSD (2038)
+    MAX_IFSD[0],
+    MAX_IFSD[1],
+    MAX_IFSD[2],
+    MAX_IFSD[3],
+    // dwSyncProtocols: none
+    0x00, 0x00, 0x00, 0x00,
+    // dwMechanical: no special characteristics
+    0x00, 0x00, 0x00, 0x00,
+
+    // dwFeatures, see following comments
+    // Auto configuration based on ATR
+    // Auto activation on insert
+    // Auto voltage selection
+    // Auto clock change
+    // Auto baud rate change
+    // Auto parameter negotiation made by CCID
+    // Short and extended APDU level exchange
+    0xFE, 0x00, 0x04, 0x00,
+
+    // dwMaxCCIDMsgLen (3072)
+    // gnuk: 271
+    MAX_MSG_LENGTH_LE[0],
+    MAX_MSG_LENGTH_LE[1],
+    MAX_MSG_LENGTH_LE[2],
+    MAX_MSG_LENGTH_LE[3],
+
+    // bClassGetResponse ("echo")
+    0xFF,
+    // bClassEnvelope ("echo"), gnuk: 0
+    0xFF,
+    // wlcdLayout (none)
+    0x00, 0x00,
+    // bPinSupport
+    PIN_SUPPORT,
+    // bMaxCCIDBusySlots
+    MAX_BUSY_SLOTS,
+];
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..7a0a5af
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,10 @@
+#![no_std]
+
+//! https://www.usb.org/sites/default/files/DWG_Smart-Card_CCID_Rev110.pdf
+//! https://www.usb.org/sites/default/files/DWG_Smart-Card_USB-ICC_ICCD_rev10.pdf
+
+pub mod constants;
+pub mod class;
+pub mod pipe;
+
+pub use class::Ccid;
diff --git a/src/pipe.rs b/src/pipe.rs
new file mode 100644
index 0000000..ee2484f
--- /dev/null
+++ b/src/pipe.rs
@@ -0,0 +1,284 @@
+use core::{
+    borrow::{Borrow, BorrowMut},
+    convert::{TryFrom, TryInto},
+};
+
+use cortex_m_semihosting::hprintln;
+
+use crate::constants::*;
+
+use usb_device::class_prelude::*;
+
+
+pub struct Pipe<Bus>
+where
+    Bus: UsbBus + 'static,
+{
+    pub(crate) read: EndpointOut<'static, Bus>,
+    pub(crate) write: EndpointIn<'static, Bus>,
+    // pub(crate) rpc: TransportEndpoint<'rpc>,
+    packet: Packet,
+    buffer: [u8; MAX_MSG_LENGTH],
+}
+
+impl<Bus> Pipe<Bus>
+where
+    Bus: 'static + UsbBus,
+{
+    pub(crate) fn new(
+        read: EndpointOut<'static, Bus>,
+        write: EndpointIn<'static, Bus>,
+    )
+        -> Self { Self {
+            read,
+            write,
+            packet: Packet { buffer: [0u8; PACKET_SIZE] },
+            buffer: [0u8; MAX_MSG_LENGTH],
+        } }
+}
+
+#[derive(Copy, Clone)]
+pub struct Packet {
+    buffer: [u8; PACKET_SIZE as _],
+}
+
+impl core::fmt::Debug for Packet {
+
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        let mut debug_struct = f.debug_struct("Packet");
+        let mut debug_struct = match self.msg_type() {
+            Ok(message_type) => debug_struct.field("type", &message_type),
+            Err(()) => debug_struct.field("type", &self[0]),
+        };
+        debug_struct
+            .field("slot", &self.slot())
+            .field("seq", &self.slot())
+            // other fields?
+            // .field("data[..16]", &self.data()[..16])
+            // .field("data", self.data())
+            .finish()
+    }
+}
+
+#[repr(u8)]
+#[derive(Copy, Clone, Debug)]
+pub enum MessageType {
+    PowerOn = 0x62,
+    PowerOff = 0x63,
+    GetSlotStatus = 0x65,
+    TransferBlock = 0x6f,
+}
+
+pub struct SlotStatus {
+    seq: u8
+}
+
+impl SlotStatus {
+    pub fn new(seq: u8) -> Self {
+        Self { seq }
+    }
+}
+
+impl From<SlotStatus> for Packet {
+    fn from(slot_status: SlotStatus) -> Self {
+        let mut buffer = [0u8; PACKET_SIZE];
+        buffer[0] = 0x81;
+        // buffer[1..5] = 0, no extra data
+        // buffer[5] = 0, only one slot
+        buffer[6] = slot_status.seq;
+        // buffer[7] = 0, status
+        // buffer[8] = 0, error
+        // buffer[9] = 0, chain parameter, this is complete
+        Packet { buffer }
+    }
+}
+
+pub struct DataBlock<'a> {
+    seq: u8,
+    data: &'a [u8],
+
+}
+
+impl<'a> DataBlock<'a> {
+    pub fn new(seq: u8, data: &'a [u8]) -> Self {
+        assert!(data.len() + 10 <= PACKET_SIZE);
+        Self { seq, data }
+    }
+}
+
+impl<'a> From<DataBlock<'a>> for Packet {
+    fn from(data_block: DataBlock) -> Self {
+        let mut buffer = [0u8; PACKET_SIZE];
+        let len = data_block.data.len();
+        buffer[0] = 0x80;
+        buffer[1..5].copy_from_slice(&len.to_le_bytes());
+        // buffer[5] = 0, only one slot
+        buffer[6] = data_block.seq;
+        // buffer[7] = 0, status
+        // buffer[8] = 0, error
+        // buffer[9] = 0, chain parameter, this is complete
+        buffer[10..][..len].copy_from_slice(data_block.data);
+        Packet { buffer }
+    }
+}
+
+impl core::convert::TryFrom<u8> for MessageType {
+    type Error = ();
+
+    fn try_from(message_type_byte: u8) -> core::result::Result<Self, ()> {
+        Ok(match message_type_byte {
+            0x62 => Self::PowerOn,
+            0x63 => Self::PowerOff,
+            0x65 => Self::GetSlotStatus,
+            0x6f => Self::TransferBlock,
+            _ => return Err(()),
+        })
+    }
+}
+
+impl Packet {
+    #[inline(always)]
+    pub fn msg_type(&self) -> core::result::Result<MessageType, ()> {
+        self[0].try_into()
+    }
+
+    #[inline(always)]
+    pub fn len(&self) -> usize {
+        u32::from_le_bytes(self[1..5].try_into().unwrap()) as usize
+    }
+
+    #[inline(always)]
+    pub fn slot(&self) -> u8 {
+        // we have only one slot
+        assert!(self[5] == 0);
+        *&self[5]
+    }
+
+    #[inline(always)]
+    pub fn seq(&self) -> u8 { *&self[6] }
+
+    //  either three message specific bytes, or
+    //  a status field (1 byte), an error field and one message specific byte
+
+    #[inline(always)]
+    pub fn data(&self) -> &[u8] { &self[10..] }
+}
+
+// impl core::borrow::Borrow<[u8; PACKET_SIZE]> for Packet {
+//     fn borrow(&self) -> &[u8; PACKET_SIZE] {
+//         &self.buffer
+//     }
+// }
+
+// impl core::borrow::BorrowMut<[u8; PACKET_SIZE]> for Packet {
+//     fn borrow_mut(&mut self) -> &mut [u8; PACKET_SIZE] {
+//         &mut self.buffer
+//     }
+// }
+
+impl core::ops::Deref for Packet {
+    type Target = [u8];
+    fn deref(&self) -> &Self::Target {
+        // let len = self.len();
+        // &self.buffer[..10 + len]
+        &self.buffer
+    }
+}
+
+impl core::ops::DerefMut for Packet {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        // let len = self.len();
+        // &mut self.buffer[..10 + len]
+        &mut self.buffer
+    }
+}
+
+
+impl<Bus> Pipe<Bus>
+where
+    Bus: 'static + UsbBus
+{
+    pub fn read_and_handle_packet(&mut self) {
+        // let data: &mut [u8; PACKET_SIZE] = self.packet.borrow_mut();
+        // let read = match self.read.read(&mut data[..]) {
+        let read = match self.read.read(&mut self.packet) {
+        // let read = match self.read.read(&mut self.packet.borrow_mut()[..]) {
+            Ok(read) => {
+                // all packets have 10 byte header before eventual data
+                if read < 10 { panic!("unexpected small packet"); }
+                read
+            }
+            Err(_) => {
+                // usb-device lists WouldBlock + BufferOverflow as possible errors.
+                // both should not occur here, and we can't do anything anyway.
+                panic!("unexpected read error");
+            }
+        };
+
+        hprintln!("got a packet of len {}: {:?}", read, &self.packet).ok();
+
+        if let Ok(msg_type) = self.packet.msg_type() {
+            match msg_type {
+                MessageType::PowerOff |
+                MessageType::GetSlotStatus => {
+                    self.send_slot_status();
+                }
+
+                MessageType::PowerOn => {
+                    self.send_atr();
+                }
+
+                MessageType::TransferBlock => {
+                    //
+                }
+            }
+        }
+    }
+
+    fn send_slot_status(&self) {
+        let packet = Packet::from(SlotStatus::new(self.packet.seq()));
+        hprintln!("answering with: {:?}", &packet).ok();
+        match self.write.write(&packet[..10 + packet.len()]) {
+            Ok(10) => {}
+
+            Ok(n) => panic!("expected to send exactly 10 bytes, sent {}", n),
+            Err(UsbError::WouldBlock) => panic!("would block not handled yet"),
+            Err(e) => panic!("unexpected error {:?}", e),
+        }
+    }
+
+    fn send_atr(&self) {
+        let packet = Packet::from(DataBlock::new(
+            self.packet.seq(),
+            &[0x3b, 0x8c,0x80,0x01],
+        ));
+        hprintln!("answering with: {:?}", &packet).ok();
+
+        match self.write.write(&packet[..10 + packet.len()]) {
+            Ok(14) => {}
+
+            Ok(n) => panic!("expected to send exactly 14 bytes, sent {}", n),
+            Err(UsbError::WouldBlock) => panic!("would block not handled yet"),
+            Err(e) => panic!("unexpected error {:?}", e),
+        }
+    }
+
+    pub fn maybe_write_packet(&mut self) {
+        // let result = self.write.write(&packet);
+
+        // match result {
+        //     Err(UsbError::WouldBlock) => {
+        //         // fine, can't write try later
+        //         // this shouldn't happen probably
+        //     },
+    }
+
+    // pub fn read_address(&self) -> EndpointAddress {
+    //     self.read.address()
+    // }
+
+    // pub fn write_address(&self) -> EndpointAddress {
+    //     self.write.address()
+    // }
+
+}