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usb-firewall-fork/Downstream/Src/downstream_statemachine.c

303 lines
8.5 KiB

/*
* downstream_statemachine.c
*
* Created on: 2/08/2015
* Author: Robert Fisk
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/
#include "downstream_statemachine.h"
#include "downstream_interface_def.h"
#include "downstream_spi.h"
#include "downstream_msc.h"
#include "downstream_hid.h"
#include "usbh_core.h"
#include "usbh_msc.h"
#include "usbh_hid.h"
#include "led.h"
DownstreamStateTypeDef DownstreamState = STATE_DEVICE_NOT_READY;
InterfaceCommandClassTypeDef ConfiguredDeviceClass = COMMAND_CLASS_INTERFACE;
uint8_t NotifyDisconnectReply = 0;
static void Downstream_PacketProcessor_Interface(DownstreamPacketTypeDef* receivedPacket);
static void Downstream_PacketProcessor_Interface_ReplyNotifyDevice(DownstreamPacketTypeDef* replyPacket);
static void Downstream_PacketProcessor_NotifyDisconnectReply(DownstreamPacketTypeDef* packetToSend);
void Downstream_InitStateMachine(void)
{
if ((DownstreamState != STATE_DEVICE_NOT_READY) ||
(ConfiguredDeviceClass != COMMAND_CLASS_INTERFACE))
{
DOWNSTREAM_STATEMACHINE_FREAKOUT;
return;
}
Downstream_InitSPI();
//Prepare to receive our first packet from Upstream!
Downstream_ReceivePacket(Downstream_PacketProcessor);
}
void Downstream_PacketProcessor(DownstreamPacketTypeDef* receivedPacket)
{
if (DownstreamState >= STATE_ERROR)
{
Downstream_ReleasePacket(receivedPacket);
return;
}
if (receivedPacket->CommandClass == COMMAND_CLASS_INTERFACE)
{
if (DownstreamState > STATE_DEVICE_READY)
{
DOWNSTREAM_STATEMACHINE_FREAKOUT;
return;
}
Downstream_PacketProcessor_Interface(receivedPacket);
return;
}
//If we get a class-specific message when our device is disconnected,
//we need to tell Upstream of the fact (and not freak out).
if (DownstreamState == STATE_DEVICE_NOT_READY)
{
Downstream_PacketProcessor_NotifyDisconnectReply(receivedPacket);
return;
}
//We should only receive class-specific messages when we are in the Active state,
//and only to our currently active device class.
if ((DownstreamState != STATE_ACTIVE) ||
(receivedPacket->CommandClass != ConfiguredDeviceClass))
{
DOWNSTREAM_STATEMACHINE_FREAKOUT;
return;
}
switch (ConfiguredDeviceClass)
{
case COMMAND_CLASS_MASS_STORAGE:
Downstream_MSC_PacketProcessor(receivedPacket);
break;
case COMMAND_CLASS_HID_MOUSE:
case COMMAND_CLASS_HID_KEYBOARD:
Downstream_HID_PacketProcessor(receivedPacket);
break;
//Add other classes here...
default:
DOWNSTREAM_STATEMACHINE_FREAKOUT;
}
}
//Used by downstream class interfaces, and SPI interface
void Downstream_PacketProcessor_FreakOut(void)
{
DOWNSTREAM_STATEMACHINE_FREAKOUT;
}
void Downstream_PacketProcessor_Interface(DownstreamPacketTypeDef* receivedPacket)
{
switch (receivedPacket->Command)
{
case COMMAND_INTERFACE_ECHO:
Downstream_TransmitPacket(receivedPacket);
Downstream_ReceivePacket(Downstream_PacketProcessor);
break;
case COMMAND_INTERFACE_NOTIFY_DEVICE:
if (DownstreamState == STATE_DEVICE_READY)
{
Downstream_PacketProcessor_Interface_ReplyNotifyDevice(receivedPacket);
return;
}
if (DownstreamState == STATE_DEVICE_NOT_READY)
{
DownstreamState = STATE_WAIT_DEVICE_READY;
Downstream_ReleasePacket(receivedPacket);
return;
}
DOWNSTREAM_STATEMACHINE_FREAKOUT;
break;
default:
DOWNSTREAM_STATEMACHINE_FREAKOUT;
}
}
void Downstream_PacketProcessor_Interface_ReplyNotifyDevice(DownstreamPacketTypeDef* replyPacket)
{
replyPacket->Length16 = DOWNSTREAM_PACKET_HEADER_LEN_16 + 1;
replyPacket->CommandClass = COMMAND_CLASS_INTERFACE;
replyPacket->Command = COMMAND_INTERFACE_NOTIFY_DEVICE;
replyPacket->Data[0] = ConfiguredDeviceClass;
if (Downstream_TransmitPacket(replyPacket) == HAL_OK)
{
DownstreamState = STATE_ACTIVE;
Downstream_ReceivePacket(Downstream_PacketProcessor);
}
}
void Downstream_PacketProcessor_GenericErrorReply(DownstreamPacketTypeDef* replyPacket)
{
replyPacket->Length16 = DOWNSTREAM_PACKET_HEADER_LEN_16;
replyPacket->CommandClass = COMMAND_CLASS_ERROR;
replyPacket->Command = COMMAND_ERROR_GENERIC;
Downstream_TransmitPacket(replyPacket);
Downstream_ReceivePacket(Downstream_PacketProcessor);
NotifyDisconnectReply = 0;
}
void Downstream_PacketProcessor_ClassReply(DownstreamPacketTypeDef* replyPacket)
{
Downstream_TransmitPacket(replyPacket);
Downstream_ReceivePacket(Downstream_PacketProcessor);
NotifyDisconnectReply = 0;
}
void Downstream_PacketProcessor_NotifyDisconnectReplyRequired(void)
{
NotifyDisconnectReply = 1;
}
void Downstream_PacketProcessor_CheckNotifyDisconnectReply(void)
{
if (NotifyDisconnectReply == 2)
{
Downstream_GetFreePacket(Downstream_PacketProcessor_NotifyDisconnectReply);
}
}
void Downstream_PacketProcessor_NotifyDisconnectReply(DownstreamPacketTypeDef* packetToSend)
{
packetToSend->Length16 = DOWNSTREAM_PACKET_HEADER_LEN_16;
packetToSend->CommandClass = COMMAND_CLASS_ERROR;
packetToSend->Command = COMMAND_ERROR_DEVICE_DISCONNECTED;
Downstream_PacketProcessor_ClassReply(packetToSend);
}
//This callback receives various event ids from the host stack,
//either at INT_PRIORITY_OTG_FS or from main().
void Downstream_HostUserCallback(USBH_HandleTypeDef *phost, uint8_t id)
{
InterfaceCommandClassTypeDef newActiveClass = COMMAND_CLASS_INTERFACE;
if (DownstreamState >= STATE_ERROR)
{
return;
}
//Called from USB interrupt.
//Simple function shouldn't need to worry about preempting anything important.
if (id == HOST_USER_DISCONNECTION)
{
DownstreamState = STATE_DEVICE_NOT_READY;
if (NotifyDisconnectReply == 1)
{
NotifyDisconnectReply = 2; //Request a 'device disconnected' reply when we get back to main()
}
return;
}
//Called from main()
if (id == HOST_USER_CLASS_ACTIVE)
{
switch (phost->pActiveClass->ClassCode)
{
case USB_MSC_CLASS:
newActiveClass = Downstream_MSC_ApproveConnectedDevice();
break;
case USB_HID_CLASS:
newActiveClass = Downstream_HID_ApproveConnectedDevice();
break;
//Add other classes here...
}
//Unsupported device classes will cause a slow fault flash.
//This is distinct from the fast freakout flash caused by internal errors or attacks.
//We consider supported classes that fail their approval checks to also be unsupported devices.
if (newActiveClass == COMMAND_CLASS_INTERFACE)
{
USB_Host_Disconnect();
LED_Fault_SetBlinkRate(LED_SLOW_BLINK_RATE);
DownstreamState = STATE_ERROR;
return;
}
//If we already configured a device class, we cannot change to a different one without rebooting.
//This blocks 'hidden device' BadUSB attacks.
if ((ConfiguredDeviceClass != COMMAND_CLASS_INTERFACE) &&
(ConfiguredDeviceClass != newActiveClass))
{
DOWNSTREAM_STATEMACHINE_FREAKOUT;
return;
}
ConfiguredDeviceClass = newActiveClass;
if (DownstreamState == STATE_WAIT_DEVICE_READY)
{
Downstream_GetFreePacket(Downstream_PacketProcessor_Interface_ReplyNotifyDevice);
return;
}
if (DownstreamState == STATE_DEVICE_NOT_READY)
{
DownstreamState = STATE_DEVICE_READY;
return;
}
DOWNSTREAM_STATEMACHINE_FREAKOUT;
return;
}
//Called from main():
if ((id == HOST_USER_CLASS_FAILED) ||
(id == HOST_USER_UNRECOVERED_ERROR)) //Probably due to a crappy device that won't enumerate!
{
//Unsupported device classes will cause a slow fault flash.
//This is distinct from the fast freakout flash caused by internal errors or attacks.
USB_Host_Disconnect();
LED_Fault_SetBlinkRate(LED_SLOW_BLINK_RATE);
DownstreamState = STATE_ERROR;
return;
}
}