secure-hid/src/demo.c

/*
 * This file is part of the libusbhost library
 * hosted at http://github.com/libusbhost/libusbhost
 *
 * Copyright (C) 2015 Amir Hammad <amir.hammad@hotmail.com>
 *
 *
 * libusbhost is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "usart_helpers.h"
#include "usbh_core.h"
#include "usbh_lld_stm32f4.h"
#include "usbh_driver_hid.h"
#include "usbh_driver_hub.h"
#include "rand_stm32.h"
#include "packet_interface.h"
#include "noise.h"

#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/usart.h>
#include <libopencm3/stm32/timer.h>
#include <libopencm3/stm32/otg_hs.h>
#include <libopencm3/stm32/otg_fs.h>
#include <libopencm3/stm32/dma.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencmsis/core_cm3.h>

#include <stdint.h>
#include <string.h>
#include <stdlib.h>

#ifndef USE_STM32F4_USBH_DRIVER_FS
#error The full-speed USB driver must be enabled with USE_STM32F4_USBH_DRIVER_FS in usbh_config.h!
#endif


void _fini(void);

static inline void delay_ms_busy_loop(uint32_t ms) {
	for (volatile uint32_t i = 0; i < 14903*ms; i++);
}


/* Set STM32 to 168 MHz. */
static void clock_setup(void) {
	rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_168MHZ]);

	rcc_periph_clock_enable(RCC_GPIOA);
	rcc_periph_clock_enable(RCC_GPIOE);

	rcc_periph_clock_enable(RCC_USART1);
	rcc_periph_clock_enable(RCC_USART2);
	rcc_periph_clock_enable(RCC_OTGFS);
	rcc_periph_clock_enable(RCC_TIM6);
	rcc_periph_clock_enable(RCC_DMA2);
	rcc_periph_clock_enable(RCC_DMA1);

	rcc_periph_clock_enable(RCC_RNG);
}


/* setup 10kHz timer */
static void tim6_setup(void) {
	timer_reset(TIM6);
	timer_set_prescaler(TIM6, 8400 - 1);	// 84Mhz/10kHz - 1
	timer_set_period(TIM6, 65535);			// Overflow in ~6.5 seconds
	timer_enable_counter(TIM6);
}

static uint32_t tim6_get_time_us(void)
{
	uint32_t cnt = timer_get_counter(TIM6);

	// convert to 1MHz less precise timer value -> units: microseconds
	uint32_t time_us = cnt * 100;

	return time_us;
}

static void gpio_setup(void)
{
    /* D2, D3 LEDs */
	gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO6 | GPIO7);
	gpio_set(GPIOA, GPIO6 | GPIO7);

    /* USB OTG FS phy outputs */
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO11 | GPIO12);
	gpio_set_af(GPIOA, GPIO_AF10, GPIO11 | GPIO12);

	/* USART1 (debug) */
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9 | GPIO10);
	gpio_set_af(GPIOA, GPIO_AF7, GPIO9 | GPIO10);

    /* USART2 (host link) */
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO2 | GPIO3);
	gpio_set_af(GPIOA, GPIO_AF7, GPIO2 | GPIO3);

    /* K0 (PE4)/K1 (PE3) buttons */
	gpio_mode_setup(GPIOE, GPIO_MODE_INPUT, GPIO_PUPD_PULLUP, GPIO3 | GPIO4);
}

enum packet_types {
    _RESERVED = 0,
    HID_KEYBOARD_REPORT = 1,
    HID_MOUSE_REPORT = 2
};

struct hid_report_packet {
    uint8_t type;
    uint8_t len;
    uint8_t report[8];
};

static void hid_in_message_handler(uint8_t device_id, const uint8_t *data, uint32_t length)
{
	if (length < 4) {
		LOG_PRINTF("HID report too short\n");
		return;
	}
	if (length > 8) {
		LOG_PRINTF("HID report too long\n");
		return;
	}

	int type = hid_get_type(device_id);
    if (type != HID_TYPE_KEYBOARD && type != HID_TYPE_MOUSE) {
        LOG_PRINTF("Unsupported HID report type %x\n", type);
        return;
    }

	LOG_PRINTF("Sending event %02X %02X %02X %02X\n", data[0], data[1], data[2], data[3]);
    struct hid_report_packet pkt = {
        .type = type == HID_TYPE_KEYBOARD ? HID_KEYBOARD_REPORT : HID_MOUSE_REPORT,
        .len = length,
        .report = {0}
    };
    memcpy(pkt.report, data, length);

    if (send_encrypted_message((uint8_t *)&pkt, sizeof(pkt))) {
        LOG_PRINTF("Error sending HID report packet\n");
        return;
    }
}

volatile struct {
    struct dma_buf dma;
    uint8_t data[256];
} debug_buf = { .dma = { .len = sizeof(debug_buf.data) } };

struct dma_usart_file debug_out_s = {
    .usart = DEBUG_USART,
    .baudrate = DEBUG_USART_BAUDRATE,
    .dma = DMA(DEBUG_USART_DMA_NUM),
    .stream = DEBUG_USART_DMA_STREAM_NUM,
    .channel = DEBUG_USART_DMA_CHANNEL_NUM,
    .irqn = NVIC_DMA_IRQ(DEBUG_USART_DMA_NUM, DEBUG_USART_DMA_STREAM_NUM),
    .buf = &debug_buf.dma
};
struct dma_usart_file *debug_out = &debug_out_s;

void DMA_ISR(DEBUG_USART_DMA_NUM, DEBUG_USART_DMA_STREAM_NUM)(void) {
	dma_clear_interrupt_flags(debug_out->dma, debug_out->stream, DMA_TCIF);

    if (debug_out->buf->wr_pos != debug_out->buf->xfr_end) /* buffer not empty */
        schedule_dma(debug_out);
}


int main(void)
{
	clock_setup();
	gpio_setup();

	/* provides time_curr_us to usbh_poll function */
	tim6_setup();

#ifdef USART_DEBUG
    usart_dma_init(debug_out);
#endif

    usart_dma_init(usart2_out);
    usart_enable_rx_interrupt(USART2);
    nvic_enable_irq(NVIC_USART2_IRQ);
    nvic_set_priority(NVIC_USART2_IRQ, 3<<4);
    nvic_set_priority(debug_out_s.irqn, 1<<4);

	LOG_PRINTF("\n==================================\n");
	LOG_PRINTF("SecureHID device side initializing\n");
	LOG_PRINTF("==================================\n");

    LOG_PRINTF("Initializing USB...\n");
    const hid_config_t hid_config = { .hid_in_message_handler = &hid_in_message_handler };
	hid_driver_init(&hid_config);
	hub_driver_init();
    const usbh_dev_driver_t *device_drivers[] = { &usbh_hub_driver, &usbh_hid_driver, NULL };
    const usbh_low_level_driver_t * const lld_drivers[] = { &usbh_lld_stm32f4_driver_fs, NULL };
	usbh_init(lld_drivers, device_drivers);

	LOG_PRINTF("Initializing RNG...\n");
    rand_init();

    /* FIXME only run this on first boot and persist key in backup sram. Allow reset via jumper-triggered factory reset function. */
    LOG_PRINTF("Generating identity key...\n");
    if (generate_identity_key())
        LOG_PRINTF("Error generating identiy key\n");

    LOG_PRINTF("Starting noise protocol handshake...\n");
    NoiseHandshakeState *handshake = start_protocol_handshake();
    if (!handshake)
        LOG_PRINTF("Error starting protocol handshake.\n");

	while (23) {
		usbh_poll(tim6_get_time_us());

        if (handshake)
            handshake = try_continue_noise_handshake(handshake);

		delay_ms_busy_loop(1); /* approx 1ms interval between usbh_poll() */
	}
}

void _fini() {
    while (1);
}