Rename from simply obd2 to more general UDS (unified diagnostics).

Fixed #1.

5 files changed, 645 insertions, 0 deletions

diff --git a/src/uds/extras.c b/src/uds/extras.c
new file mode 100644
index 00000000..2be6bdd8
--- /dev/null
+++ b/src/uds/extras.c
@@ -0,0 +1,39 @@
+#include <uds/extras.h>
+#include <uds/uds.h>
+
+// TODO everything below here is for future work...not critical for now.
+
+DiagnosticRequestHandle diagnostic_request_malfunction_indicator_status(
+        DiagnosticShims* shims,
+        DiagnosticMilStatusReceived callback) {
+    // TODO request malfunction indicator light (MIL) status - request mode 1
+    // pid 1, parse first bit
+    DiagnosticRequestHandle handle;
+    return handle;
+}
+
+DiagnosticRequestHandle diagnostic_request_vin(DiagnosticShims* shims,
+        DiagnosticVinReceived callback) {
+    DiagnosticRequestHandle handle;
+    return handle;
+}
+
+DiagnosticRequestHandle diagnostic_request_dtc(DiagnosticShims* shims,
+        DiagnosticTroubleCodeType dtc_type,
+        DiagnosticTroubleCodesReceived callback) {
+    DiagnosticRequestHandle handle;
+    return handle;
+}
+
+bool diagnostic_clear_dtc(DiagnosticShims* shims) {
+    return false;
+}
+
+DiagnosticRequestHandle diagnostic_enumerate_pids(DiagnosticShims* shims,
+        DiagnosticRequest* request, DiagnosticPidEnumerationReceived callback) {
+    // before calling the callback, split up the received bytes into 1 or 2 byte
+    // chunks depending on the mode so the final pid list is actual 1 or 2 byte PIDs
+    // TODO request supported PIDs  - request PID 0 and parse 4 bytes in response
+    DiagnosticRequestHandle handle;
+    return handle;
+}
diff --git a/src/uds/extras.h b/src/uds/extras.h
new file mode 100644
index 00000000..c59c7bad
--- /dev/null
+++ b/src/uds/extras.h
@@ -0,0 +1,73 @@
+#ifndef __EXTRAS_H__
+#define __EXTRAS_H__
+
+#include <uds/uds_types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// TODO everything in here is unused for the moment!
+
+typedef enum {
+    POWERTRAIN = 0x0,
+    CHASSIS = 0x1,
+    BODY = 0x2,
+    NETWORK = 0x3
+} DiagnosticTroubleCodeGroup;
+
+typedef struct {
+    DiagnosticTroubleCodeGroup group;
+    uint8_t group_num;
+    uint8_t code;
+} DiagnosticTroubleCode;
+
+
+/* Private: TODO unused for now
+ */
+typedef enum {
+    DTC_EMISSIONS,
+    DTC_DRIVE_CYCLE,
+    DTC_PERMANENT
+} DiagnosticTroubleCodeType;
+
+
+// TODO should we enumerate every OBD-II PID? need conversion formulas, too
+typedef struct {
+    uint16_t pid;
+    uint8_t bytes_returned;
+    float min_value;
+    float max_value;
+} DiagnosticParameter;
+
+typedef void (*DiagnosticMilStatusReceived)(bool malfunction_indicator_status);
+typedef void (*DiagnosticVinReceived)(uint8_t vin[]);
+typedef void (*DiagnosticTroubleCodesReceived)(
+        DiagnosticMode mode, DiagnosticTroubleCode* codes);
+typedef void (*DiagnosticPidEnumerationReceived)(
+        const DiagnosticResponse* response, uint16_t* pids);
+
+DiagnosticRequestHandle diagnostic_request_malfunction_indicator_status(
+        DiagnosticShims* shims,
+        DiagnosticMilStatusReceived callback);
+
+DiagnosticRequestHandle diagnostic_request_vin(DiagnosticShims* shims,
+        DiagnosticVinReceived callback);
+
+DiagnosticRequestHandle diagnostic_request_dtc(DiagnosticShims* shims,
+        DiagnosticTroubleCodeType dtc_type,
+        DiagnosticTroubleCodesReceived callback);
+
+bool diagnostic_clear_dtc(DiagnosticShims* shims);
+
+DiagnosticRequestHandle diagnostic_enumerate_pids(DiagnosticShims* shims,
+        DiagnosticRequest* request, DiagnosticPidEnumerationReceived callback);
+
+// TODO
+float diagnostic_decode_OBD2_pid(DiagnosticResponse* response);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __EXTRAS_H__
diff --git a/src/uds/uds.c b/src/uds/uds.c
new file mode 100644
index 00000000..443b05a0
--- /dev/null
+++ b/src/uds/uds.c
@@ -0,0 +1,243 @@
+#include <uds/uds.h>
+#include <bitfield/bitfield.h>
+#include <string.h>
+#include <limits.h>
+#include <stddef.h>
+#include <sys/param.h>
+
+#define ARBITRATION_ID_OFFSET 0x8
+#define MODE_RESPONSE_OFFSET 0x40
+#define NEGATIVE_RESPONSE_MODE 0x7f
+#define MAX_DIAGNOSTIC_PAYLOAD_SIZE 6
+#define MODE_BYTE_INDEX 0
+#define PID_BYTE_INDEX 1
+#define NEGATIVE_RESPONSE_MODE_INDEX 1
+#define NEGATIVE_RESPONSE_NRC_INDEX 2
+
+#ifndef MAX
+#define MAX(x, y) (((x) > (y)) ? (x) : (y))
+#endif
+
+DiagnosticShims diagnostic_init_shims(LogShim log,
+        SendCanMessageShim send_can_message,
+        SetTimerShim set_timer) {
+    DiagnosticShims shims = {
+        log: log,
+        send_can_message: send_can_message,
+        set_timer: set_timer
+    };
+    return shims;
+}
+
+static void setup_receive_handle(DiagnosticRequestHandle* handle) {
+    if(handle->request.arbitration_id == OBD2_FUNCTIONAL_BROADCAST_ID) {
+        uint16_t response_id;
+        for(response_id = 0;
+                response_id < OBD2_FUNCTIONAL_RESPONSE_COUNT; ++response_id) {
+            handle->isotp_receive_handles[response_id] = isotp_receive(
+                    &handle->isotp_shims, OBD2_FUNCTIONAL_RESPONSE_START + response_id,
+                    NULL);
+        }
+        handle->isotp_receive_handle_count = OBD2_FUNCTIONAL_RESPONSE_COUNT;
+    } else {
+        handle->isotp_receive_handle_count = 1;
+        handle->isotp_receive_handles[0] = isotp_receive(&handle->isotp_shims,
+                handle->request.arbitration_id + ARBITRATION_ID_OFFSET,
+                NULL);
+    }
+}
+
+
+DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
+        DiagnosticRequest* request, DiagnosticResponseReceived callback) {
+    DiagnosticRequestHandle handle = {
+        request: *request,
+        callback: callback,
+        success: false,
+        completed: false
+    };
+
+    uint8_t payload[MAX_DIAGNOSTIC_PAYLOAD_SIZE] = {0};
+    payload[MODE_BYTE_INDEX] = request->mode;
+    if(request->pid_length > 0) {
+        set_bitfield(request->pid, PID_BYTE_INDEX * CHAR_BIT,
+                request->pid_length * CHAR_BIT, payload, sizeof(payload));
+    }
+    if(request->payload_length > 0) {
+        memcpy(&payload[PID_BYTE_INDEX + request->pid_length],
+                request->payload, request->payload_length);
+    }
+
+    handle.isotp_shims = isotp_init_shims(shims->log,
+            shims->send_can_message,
+            shims->set_timer);
+
+    handle.isotp_send_handle = isotp_send(&handle.isotp_shims,
+            request->arbitration_id, payload,
+            1 + request->payload_length + request->pid_length,
+            NULL);
+    if(shims->log != NULL) {
+        shims->log("Sending diagnostic request: arb_id: 0x%02x, mode: 0x%x, pid: 0x%x, payload: 0x%02x%02x%02x%02x%02x%02x%02x, size: %d\r\n",
+                request->arbitration_id,
+                request->mode,
+                request->pid,
+                request->payload[0],
+                request->payload[1],
+                request->payload[2],
+                request->payload[3],
+                request->payload[4],
+                request->payload[5],
+                request->payload[6],
+                request->payload_length);
+    }
+
+    setup_receive_handle(&handle);
+
+    // TODO notes on multi frame:
+    // TODO what are the timers for exactly?
+    //
+    // when sending multi frame, send 1 frame, wait for a response
+    // if it says send all, send all right away
+    // if it says flow control, set the time for the next send
+    // instead of creating a timer with an async callback, add a process_handle
+    // function that's called repeatedly in the main loop - if it's time to
+    // send, we do it. so there's a process_handle_send and receive_can_frame
+    // that are just called continuously from the main loop. it's a waste of a
+    // few cpu cycles but it may be more  natural than callbacks.
+    //
+    // what woudl a timer callback look like...it would need to pass the handle
+    // and that's all. seems like a context void* would be able to capture all
+    // of the information but arg, memory allocation. look at how it's done in
+    // the other library again
+    //
+    return handle;
+}
+
+DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
+        DiagnosticPidRequestType pid_request_type, uint16_t arbitration_id,
+        uint16_t pid, DiagnosticResponseReceived callback) {
+    DiagnosticRequest request = {
+        arbitration_id: arbitration_id,
+        mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
+        pid: pid,
+        pid_length: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 1 : 2
+    };
+
+    return diagnostic_request(shims, &request, callback);
+}
+
+static bool handle_negative_response(IsoTpMessage* message,
+        DiagnosticResponse* response, DiagnosticShims* shims) {
+    bool response_was_negative = false;
+    if(response->mode == NEGATIVE_RESPONSE_MODE) {
+        response_was_negative = true;
+        if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
+            response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
+        }
+
+        if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
+            response->negative_response_code = message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
+        }
+
+        response->success = false;
+        response->completed = true;
+    }
+    return response_was_negative;
+}
+
+static bool handle_positive_response(DiagnosticRequestHandle* handle,
+        IsoTpMessage* message, DiagnosticResponse* response,
+        DiagnosticShims* shims) {
+    bool response_was_positive = false;
+    if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
+        response_was_positive = true;
+        // hide the "response" version of the mode from the user
+        // if it matched
+        response->mode = handle->request.mode;
+        response->has_pid = false;
+        if(handle->request.pid_length > 0 && message->size > 1) {
+            response->has_pid = true;
+            if(handle->request.pid_length == 2) {
+                response->pid = get_bitfield(message->payload, message->size,
+                        PID_BYTE_INDEX * CHAR_BIT, sizeof(uint16_t) * CHAR_BIT);
+            } else {
+                response->pid = message->payload[PID_BYTE_INDEX];
+            }
+
+        }
+
+        uint8_t payload_index = 1 + handle->request.pid_length;
+        response->payload_length = MAX(0, message->size - payload_index);
+        if(response->payload_length > 0) {
+            memcpy(response->payload, &message->payload[payload_index],
+                    response->payload_length);
+        }
+
+        if((handle->request.pid_length == 0 && !response->has_pid)
+                || response->pid == handle->request.pid) {
+            response->success = true;
+            response->completed = true;
+        } else {
+            response_was_positive = false;
+        }
+    }
+    return response_was_positive;
+}
+
+DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
+        DiagnosticRequestHandle* handle, const uint16_t arbitration_id,
+        const uint8_t data[], const uint8_t size) {
+
+    DiagnosticResponse response = {
+        arbitration_id: arbitration_id,
+        success: false,
+        completed: false
+    };
+
+    if(!handle->isotp_send_handle.completed) {
+        isotp_continue_send(&handle->isotp_shims,
+                &handle->isotp_send_handle, arbitration_id, data, size);
+    } else {
+        uint8_t i;
+        for(i = 0; i < handle->isotp_receive_handle_count; ++i) {
+            IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
+                    &handle->isotp_receive_handles[i], arbitration_id, data, size);
+
+            // TODO as of now we're completing the handle as soon as one
+            // broadcast response is received....need to hang on for 100ms
+            if(message.completed) {
+                if(message.size > 0) {
+                    response.mode = message.payload[0];
+                    if(handle_negative_response(&message, &response, shims)) {
+                        shims->log("Received a negative response to mode %d on arb ID 0x%x",
+                                response.mode, response.arbitration_id);
+                        handle->success = true;
+                        handle->completed = true;
+                    } else if(handle_positive_response(handle, &message, &response,
+                                shims)) {
+                        shims->log("Received a positive mode %d response on arb ID 0x%x",
+                                response.mode, response.arbitration_id);
+                        handle->success = true;
+                        handle->completed = true;
+                    } else {
+                        shims->log("Response was for a mode 0x%x request (pid 0x%x), not our mode 0x%x request (pid 0x%x)",
+                                MAX(0, response.mode - MODE_RESPONSE_OFFSET),
+                                response.pid, handle->request.mode,
+                                handle->request.pid);
+                        // TODO just leave handles open until the user decides
+                        // to be done with it - keep a count of valid responses
+                        // received.
+                    }
+                } else {
+                    shims->log("Received an empty response on arb ID 0x%x",
+                            response.arbitration_id);
+                }
+
+                if(handle->completed && handle->callback != NULL) {
+                    handle->callback(&response);
+                }
+            }
+        }
+    }
+    return response;
+}
diff --git a/src/uds/uds.h b/src/uds/uds.h
new file mode 100644
index 00000000..091d3c9f
--- /dev/null
+++ b/src/uds/uds.h
@@ -0,0 +1,102 @@
+#ifndef __UDS_H__
+#define __UDS_H__
+
+#include <uds/uds_types.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#define OBD2_FUNCTIONAL_BROADCAST_ID 0x7df
+#define OBD2_FUNCTIONAL_RESPONSE_START 0x7e8
+#define OBD2_FUNCTIONAL_RESPONSE_COUNT 8
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Public: Initialize an DiagnosticShims with the given callback functions.
+ *
+ * If any callbacks are not to be used, set them to NULL. For documentation of
+ * the function type signatures, see higher up in this header file. This struct
+ * is a handy encapsulation used to pass the shims around to the various
+ * diagnostic_* functions.
+ *
+ * Returns a struct with the fields initailized to the callbacks.
+ */
+DiagnosticShims diagnostic_init_shims(LogShim log,
+        SendCanMessageShim send_can_message,
+        SetTimerShim set_timer);
+
+/* Public: Initiate a diagnostic request and return a handle, ready to completly
+ * send the request and process the response via
+ * diagnostic_receive_can_frame(...).
+ *
+ * shims -  Low-level shims required to send CAN messages, etc.
+ * request -
+ * callback - an optional function to be called when the response is receved
+ *      (use NULL if no callback is required).
+ *
+ * Returns a handle to be used with diagnostic_receive_can_frame to complete
+ * sending the request and receive the response. The 'completed' field in the
+ * returned DiagnosticRequestHandle will be true when the message is completely
+ * sent.
+ */
+DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
+        DiagnosticRequest* request, DiagnosticResponseReceived callback);
+
+/* Public: Request a PID from the given arbitration ID, determining the mode
+ * automatically based on the PID type.
+ *
+ * shims -  Low-level shims required to send CAN messages, etc.
+ * pid_request_type - either DIAGNOSTIC_STANDARD_PID (will use mode 0x1 and 1
+ *      byte PIDs) or DIAGNOSTIC_ENHANCED_PID (will use mode 0x22 and 2 byte
+ *      PIDs)
+ * arbitration_id - The arbitration ID to send the request to.
+ * pid - The PID to request from the other node.
+ * callback - an optional function to be called when the response is receved
+ *      (use NULL if no callback is required).
+ *
+ * Returns a handle to be used with diagnostic_receive_can_frame to complete
+ * sending the request and receive the response. The 'completed' field in the
+ * returned DiagnosticRequestHandle will be true when the message is completely
+ * sent.
+ */
+DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
+        DiagnosticPidRequestType pid_request_type, uint16_t arbitration_id,
+        uint16_t pid, DiagnosticResponseReceived callback);
+
+/* Public: Continue to send and receive a single diagnostic request, based on a
+ * freshly received CAN message.
+ *
+ * shims -  Low-level shims required to send CAN messages, etc.
+ * handle - A DiagnosticRequestHandle previously returned by one of the
+ *      diagnostic_request*(..) functions.
+ * arbitration_id - The arbitration_id of the received CAN message.
+ * data - The data of the received CAN message.
+ * size - The size of the data in the received CAN message.
+ *
+ * Returns true if the request was completed and response received, or the
+ * request was otherwise cancelled. Check the 'success' field of the handle to
+ * see if it was successful.
+ */
+DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
+        DiagnosticRequestHandle* handle,
+        const uint16_t arbitration_id, const uint8_t data[],
+        const uint8_t size);
+
+/* Public: Render a DiagnosticResponse as a string into the given buffer.
+ *
+ * TODO implement this
+ *
+ * message - the response to convert to a string, for debug logging.
+ * destination - the target string buffer.
+ * destination_length - the size of the destination buffer, i.e. the max size
+ *      for the rendered string.
+ */
+// void diagnostic_response_to_string(const DiagnosticResponse* response,
+        // char* destination, size_t destination_length);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __UDS_H__
diff --git a/src/uds/uds_types.h b/src/uds/uds_types.h
new file mode 100644
index 00000000..f8c7ef08
--- /dev/null
+++ b/src/uds/uds_types.h
@@ -0,0 +1,188 @@
+#ifndef __UDS_TYPES_H__
+#define __UDS_TYPES_H__
+
+#include <isotp/isotp.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// TODO This isn't true for multi frame messages - we may need to dynamically
+// allocate this in the future
+#define MAX_UDS_PAYLOAD_LENGTH 7
+#define MAX_RESPONDING_ECU_COUNT 8
+#define VIN_LENGTH 17
+
+/* Private: The four main types of diagnositc requests that determine how the
+ * request should be parsed and what type of callback should be used.
+ *
+ * TODO this may not be used...yet?
+ */
+typedef enum {
+    DIAGNOSTIC_REQUEST_TYPE_PID,
+    DIAGNOSTIC_REQUEST_TYPE_DTC,
+    DIAGNOSTIC_REQUEST_TYPE_MIL_STATUS,
+    DIAGNOSTIC_REQUEST_TYPE_VIN
+} DiagnosticRequestType;
+
+/* Public: A container for a single diagnostic request.
+ *
+ * The only required fields are the arbitration_id and mode.
+ *
+ * arbitration_id - The arbitration ID to send the request.
+ * mode - The OBD-II mode for the request.
+ * pid - (optional) The PID to request, if the mode requires one.
+ * pid_length - The length of the PID field, either 1 (standard) or 2 bytes
+ *      (extended).
+ * payload - (optional) The payload for the request, if the request requires
+ *      one. If payload_length is 0 this field is ignored.
+ * payload_length - The length of the payload, or 0 if no payload is used.
+ * type - the type of the request (TODO unused)
+ */
+typedef struct {
+    uint16_t arbitration_id;
+    uint8_t mode;
+    uint16_t pid;
+    uint8_t pid_length;
+    uint8_t payload[MAX_UDS_PAYLOAD_LENGTH];
+    uint8_t payload_length;
+    DiagnosticRequestType type;
+} DiagnosticRequest;
+
+/* Public: All possible negative response codes that could be received from a
+ * requested node.
+ *
+ * When a DiagnosticResponse is received and the 'completed' field is true, but
+ * the 'success' field is false, the 'negative_response_code' field will contain
+ * one of these values as reported by the requested node.
+ *
+ * Thanks to canbushack.com for the list of NRCs.
+ */
+typedef enum {
+    NRC_SUCCESS = 0x0,
+    NRC_SERVICE_NOT_SUPPORTED = 0x11,
+    NRC_SUB_FUNCTION_NOT_SUPPORTED = 0x12,
+    NRC_CONDITIONS_NOT_CORRECT = 0x22,
+    NRC_REQUEST_OUT_OF_RANGE = 0x31,
+    NRC_SECURITY_ACCESS_DENIED = 0x33,
+    NRC_INVALID_KEY = 0x35,
+    NRC_TOO_MANY_ATTEMPS = 0x36,
+    NRC_TIME_DELAY_NOT_EXPIRED = 0x37,
+    NRC_RESPONSE_PENDING = 0x78
+} DiagnosticNegativeResponseCode;
+
+/* Public: A partially or fully completed response to a diagnostic request.
+ *
+ * completed - True if the request is complete - some functions return a
+ *      DiagnosticResponse even when it's only partially completed, so be sure
+ *      to check this field.
+ * success - True if the request was successful. The value if this
+ *      field isn't valid if 'completed' isn't true. If this is 'false', check
+ *      the negative_response_code field for the reason.
+ * arbitration_id - The arbitration ID the response was received on.
+ * mode - The OBD-II mode for the original request.
+ * has_pid - If this is a response to a PID request, this will be true and the
+ *      'pid' field will be valid.
+ * pid - If the request was for a PID, this is the PID echo. Only valid if
+ *      'has_pid' is true.
+ * negative_response_code - If the request was not successful, 'success' will be
+ *      false and this will be set to a DiagnosticNegativeResponseCode returned
+ *      by the other node.
+ * payload - An optional payload for the response - NULL if no payload.
+ * payload_length - The length of the payload or 0 if none.
+ */
+typedef struct {
+    bool completed;
+    bool success;
+    uint16_t arbitration_id;
+    uint8_t mode;
+    bool has_pid;
+    uint16_t pid;
+    DiagnosticNegativeResponseCode negative_response_code;
+    uint8_t payload[MAX_UDS_PAYLOAD_LENGTH];
+    uint8_t payload_length;
+} DiagnosticResponse;
+
+/* Public: Friendly names for all OBD-II modes.
+ */
+typedef enum {
+    OBD2_MODE_POWERTRAIN_DIAGNOSTIC_REQUEST = 0x1,
+    OBD2_MODE_POWERTRAIN_FREEZE_FRAME_REQUEST = 0x2,
+    OBD2_MODE_EMISSIONS_DTC_REQUEST = 0x3,
+    OBD2_MODE_EMISSIONS_DTC_CLEAR = 0x4,
+    // 0x5 is for non-CAN only
+    // OBD2_MODE_OXYGEN_SENSOR_TEST = 0x5,
+    OBD2_MODE_TEST_RESULTS = 0x6,
+    OBD2_MODE_DRIVE_CYCLE_DTC_REQUEST = 0x7,
+    OBD2_MODE_CONTROL = 0x8,
+    OBD2_MODE_VEHICLE_INFORMATION = 0x9,
+    OBD2_MODE_PERMANENT_DTC_REQUEST = 0xa,
+    // this one isn't technically in uds, but both of the enhanced standards
+    // have their PID requests at 0x22
+    OBD2_MODE_ENHANCED_DIAGNOSTIC_REQUEST = 0x22
+} DiagnosticMode;
+
+/* Public the signature for an optional function to be called when a diagnostic
+ * request is complete, and a response is received or there is a fatal error.
+ *
+ * response - the completed DiagnosticResponse.
+ */
+typedef void (*DiagnosticResponseReceived)(const DiagnosticResponse* response);
+
+typedef float (*DiagnosticResponseDecoder)(const DiagnosticResponse* response);
+
+/* Public: A handle for initiating and continuing a single diagnostic request.
+ *
+ * A diagnostic request requires one or more CAN messages to be sent, and one
+ * or more CAN messages to be received before it is completed. This struct
+ * encapsulates the local state required to track the request while it is in
+ * progress.
+ *
+ * request - The original DiagnosticRequest that this handle was created for.
+ * completed - True if the request was completed successfully, or was otherwise
+ *      cancelled.
+ * success - True if the request send and receive process was successful. The
+ *      value if this field isn't valid if 'completed' isn't true.
+ */
+typedef struct {
+    DiagnosticRequest request;
+    bool success;
+    bool completed;
+
+    // Private
+    IsoTpShims isotp_shims;
+    IsoTpSendHandle isotp_send_handle;
+    IsoTpReceiveHandle isotp_receive_handles[MAX_RESPONDING_ECU_COUNT];
+    uint8_t isotp_receive_handle_count;
+    DiagnosticResponseReceived callback;
+    // DiagnosticMilStatusReceived mil_status_callback;
+    // DiagnosticVinReceived vin_callback;
+} DiagnosticRequestHandle;
+
+/* Public: The two major types of PIDs that determine the OBD-II mode and PID
+ * field length.
+ */
+typedef enum {
+    DIAGNOSTIC_STANDARD_PID,
+    DIAGNOSTIC_ENHANCED_PID
+} DiagnosticPidRequestType;
+
+/* Public: A container for the 3 shim functions used by the library to interact
+ * with the wider system.
+ *
+ * Use the diagnostic_init_shims(...) function to create an instance of this
+ * struct.
+ */
+typedef struct {
+    LogShim log;
+    SendCanMessageShim send_can_message;
+    SetTimerShim set_timer;
+} DiagnosticShims;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __UDS_TYPES_H__