From 97e448c1d9921cd084e1da70f3943bead03474ed Mon Sep 17 00:00:00 2001
From: Robin Krahl <robin.krahl@ireas.org>
Date: Mon, 18 Feb 2019 14:20:14 +0000
Subject: hid: Add support for {Get,Set}_Report requests

This patch adds support for Get_Report and Set_Report requests to
HidClass.  We parse the request metadata and the delegate the request
handling to the HidDevice.

Our HidDevice implementation, Nitrokey, stores the data sent with
Set_Report requests.  The Get_Report handling is not implemented yet.
---
 src/hid.rs | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 93 insertions(+), 13 deletions(-)

(limited to 'src/hid.rs')

diff --git a/src/hid.rs b/src/hid.rs
index a2adeb3..79ba7f0 100644
--- a/src/hid.rs
+++ b/src/hid.rs
@@ -3,10 +3,13 @@
 
 use usb_device::bus::{InterfaceNumber, StringIndex, UsbBus, UsbBusAllocator};
 use usb_device::class::{ControlIn, ControlOut, UsbClass};
-use usb_device::control::{Recipient, Request, RequestType};
+use usb_device::control;
+use usb_device::control::{Recipient, RequestType};
 use usb_device::descriptor::DescriptorWriter;
 use usb_device::endpoint::{EndpointAddress, EndpointIn};
-use usb_device::{Result, UsbError};
+use usb_device::UsbError;
+
+use crate::util::TryFrom;
 
 const SPECIFICATION_RELEASE: u16 = 0x111;
 const INTERFACE_CLASS_HID: u8 = 0x03;
@@ -37,12 +40,48 @@ enum_u8! {
     }
 }
 
+enum_u8! {
+    #[derive(Debug, Clone, Copy, PartialEq)]
+    pub enum Request {
+        GetReport = 0x01,
+        GetIdle = 0x02,
+        GetProtocol = 0x03,
+        SetReport = 0x09,
+        SetIdle = 0x0a,
+        SetProtocol = 0x0b,
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum ReportType {
+    Input,
+    Output,
+    Feature,
+    Reserved(u8),
+}
+
+impl From<u8> for ReportType {
+    fn from(val: u8) -> Self {
+        match val {
+            1 => ReportType::Input,
+            2 => ReportType::Output,
+            3 => ReportType::Feature,
+            _ => ReportType::Reserved(val),
+        }
+    }
+}
+
 pub trait HidDevice {
     fn subclass(&self) -> Subclass;
 
     fn protocol(&self) -> Protocol;
 
     fn report_descriptor(&self) -> &[u8];
+
+    fn set_report(&mut self, report_type: ReportType, report_id: u8, data: &[u8])
+        -> Result<(), ()>;
+
+    fn get_report(&mut self, report_type: ReportType, report_id: u8) -> Result<&[u8], ()>;
 }
 
 pub struct HidClass<'a, B: UsbBus, D: HidDevice> {
@@ -62,7 +101,7 @@ impl<B: UsbBus, D: HidDevice> HidClass<'_, B, D> {
         }
     }
 
-    fn get_report_descriptor(&self, index: u8, buf: &mut [u8]) -> Result<usize> {
+    fn get_report_descriptor(&self, index: u8, buf: &mut [u8]) -> usb_device::Result<usize> {
         if index == 0 {
             let report_descriptor = self.device.report_descriptor();
             let len = report_descriptor.len();
@@ -76,6 +115,26 @@ impl<B: UsbBus, D: HidDevice> HidClass<'_, B, D> {
             Err(UsbError::InvalidState)
         }
     }
+
+    fn get_report(&mut self, xfer: ControlIn<B>) {
+        let req = xfer.request();
+        let [report_type, report_id] = req.value.to_be_bytes();
+        let report_type = ReportType::from(report_type);
+        match self.device.get_report(report_type, report_id) {
+            Ok(data) => xfer.accept_with(data).ok(),
+            Err(()) => xfer.reject().ok(),
+        };
+    }
+
+    fn set_report(&mut self, xfer: ControlOut<B>) {
+        let req = xfer.request();
+        let [report_type, report_id] = req.value.to_be_bytes();
+        let report_type = ReportType::from(report_type);
+        match self.device.set_report(report_type, report_id, xfer.data()) {
+            Ok(()) => xfer.accept().ok(),
+            Err(()) => xfer.reject().ok(),
+        };
+    }
 }
 
 impl<B: UsbBus, D: HidDevice> UsbClass<B> for HidClass<'_, B, D> {
@@ -85,7 +144,10 @@ impl<B: UsbBus, D: HidDevice> UsbClass<B> for HidClass<'_, B, D> {
         self.expect_interrupt_in_complete = false;
     }
 
-    fn get_configuration_descriptors(&self, writer: &mut DescriptorWriter) -> Result<()> {
+    fn get_configuration_descriptors(
+        &self,
+        writer: &mut DescriptorWriter,
+    ) -> usb_device::Result<()> {
         writer.interface(
             self.interface,
             INTERFACE_CLASS_HID,
@@ -136,17 +198,35 @@ impl<B: UsbBus, D: HidDevice> UsbClass<B> for HidClass<'_, B, D> {
 
     fn control_in(&mut self, xfer: ControlIn<B>) {
         let req = xfer.request();
-        if req.request_type == RequestType::Standard
-            && req.recipient == Recipient::Interface
-            && req.request == Request::GET_DESCRIPTOR
-        {
-            let (dtype, index) = req.descriptor_type_index();
-            if dtype == DescriptorType::Report.into() {
-                xfer.accept(|mut buf| self.get_report_descriptor(index, &mut buf))
-                    .ok();
+        match (req.request_type, req.recipient) {
+            (RequestType::Standard, Recipient::Interface) => {
+                if req.request == control::Request::GET_DESCRIPTOR {
+                    let (dtype, index) = req.descriptor_type_index();
+                    if dtype == DescriptorType::Report.into() {
+                        xfer.accept(|mut buf| self.get_report_descriptor(index, &mut buf))
+                            .ok();
+                    }
+                }
+            }
+            (RequestType::Class, Recipient::Interface) => {
+                if let Ok(request) = Request::try_from(req.request) {
+                    if request == Request::GetReport {
+                        self.get_report(xfer);
+                    }
+                }
             }
+            _ => {}
         }
     }
 
-    fn control_out(&mut self, _xfer: ControlOut<B>) {}
+    fn control_out(&mut self, xfer: ControlOut<B>) {
+        let req = xfer.request();
+        if req.request_type == RequestType::Class && req.recipient == Recipient::Interface {
+            if let Ok(request) = Request::try_from(req.request) {
+                if request == Request::SetReport {
+                    self.set_report(xfer);
+                }
+            }
+        }
+    }
 }
-- 
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