src/uds/uds.c

   1 #include <uds/uds.h>
   2 #include <bitfield/bitfield.h>
   3 #include <canutil/read.h>
   4 #include <string.h>
   5 #include <limits.h>
   6 #include <stddef.h>
   7 #include <sys/param.h>
   8 #include <inttypes.h>
   9
  10 #define ARBITRATION_ID_OFFSET 0x8
  11 #define MODE_RESPONSE_OFFSET 0x40
  12 #define NEGATIVE_RESPONSE_MODE 0x7f
  13 #define MAX_DIAGNOSTIC_PAYLOAD_SIZE 6
  14 #define MODE_BYTE_INDEX 0
  15 #define PID_BYTE_INDEX 1
  16 #define NEGATIVE_RESPONSE_MODE_INDEX 1
  17 #define NEGATIVE_RESPONSE_NRC_INDEX 2
  18
  19 #ifndef MAX
  20 #define MAX(x, y) (((x) > (y)) ? (x) : (y))
  21 #endif
  22
  23 DiagnosticShims diagnostic_init_shims(LogShim log,
  24         SendCanMessageShim send_can_message,
  25         SetTimerShim set_timer) {
  26     DiagnosticShims shims = {
  27         log: log,
  28         send_can_message: send_can_message,
  29         set_timer: set_timer
  30     };
  31     return shims;
  32 }
  33
  34 static void setup_receive_handle(DiagnosticRequestHandle* handle) {
  35     if(handle->request.arbitration_id == OBD2_FUNCTIONAL_BROADCAST_ID) {
  36         uint32_t response_id;
  37         for(response_id = 0;
  38                 response_id < OBD2_FUNCTIONAL_RESPONSE_COUNT; ++response_id) {
  39             handle->isotp_receive_handles[response_id] = isotp_receive(
  40                     &handle->isotp_shims,
  41                     OBD2_FUNCTIONAL_RESPONSE_START + response_id,
  42                     NULL);
  43         }
  44         handle->isotp_receive_handle_count = OBD2_FUNCTIONAL_RESPONSE_COUNT;
  45     } else {
  46         handle->isotp_receive_handle_count = 1;
  47         handle->isotp_receive_handles[0] = isotp_receive(&handle->isotp_shims,
  48                 handle->request.arbitration_id + ARBITRATION_ID_OFFSET,
  49                 NULL);
  50     }
  51 }
  52
  53 static uint16_t autoset_pid_length(uint8_t mode, uint16_t pid,
  54         uint8_t pid_length) {
  55     if(pid_length == 0) {
  56         if(pid > 0xffff || (mode != 0x3e && mode > 0xa)) {
  57             pid_length = 2;
  58         } else {
  59             pid_length = 1;
  60         }
  61     }
  62     return pid_length;
  63 }
  64
  65 static void send_diagnostic_request(DiagnosticShims* shims,
  66         DiagnosticRequestHandle* handle) {
  67     uint8_t payload[MAX_DIAGNOSTIC_PAYLOAD_SIZE] = {0};
  68     payload[MODE_BYTE_INDEX] = handle->request.mode;
  69     if(handle->request.has_pid) {
  70         handle->request.pid_length = autoset_pid_length(handle->request.mode,
  71                 handle->request.pid, handle->request.pid_length);
  72         handle->request.pid_length = handle->request.pid_length;
  73         set_bitfield(handle->request.pid, PID_BYTE_INDEX * CHAR_BIT,
  74                 handle->request.pid_length * CHAR_BIT, payload,
  75                 sizeof(payload));
  76     }
  77
  78     if(handle->request.payload_length > 0) {
  79         memcpy(&payload[PID_BYTE_INDEX + handle->request.pid_length],
  80                 handle->request.payload, handle->request.payload_length);
  81     }
  82
  83     handle->isotp_send_handle = isotp_send(&handle->isotp_shims,
  84             handle->request.arbitration_id, payload,
  85             1 + handle->request.payload_length + handle->request.pid_length,
  86             NULL);
  87     if(handle->isotp_send_handle.completed &&
  88             !handle->isotp_send_handle.success) {
  89         handle->completed = true;
  90         handle->success = false;
  91         if(shims->log != NULL) {
  92             shims->log("%s", "Diagnostic request not sent");
  93         }
  94     } else if(shims->log != NULL) {
  95         char request_string[128] = {0};
  96         diagnostic_request_to_string(&handle->request, request_string,
  97                 sizeof(request_string));
  98         shims->log("Sending diagnostic request: %s", request_string);
  99     }
 100 }
 101
 102 bool diagnostic_request_sent(DiagnosticRequestHandle* handle) {
 103     return handle->isotp_send_handle.completed;
 104 }
 105
 106 void start_diagnostic_request(DiagnosticShims* shims,
 107         DiagnosticRequestHandle* handle) {
 108     handle->success = false;
 109     handle->completed = false;
 110     send_diagnostic_request(shims, handle);
 111     if(!handle->completed) {
 112         setup_receive_handle(handle);
 113     }
 114 }
 115
 116 DiagnosticRequestHandle generate_diagnostic_request(DiagnosticShims* shims,
 117         DiagnosticRequest* request, DiagnosticResponseReceived callback) {
 118     DiagnosticRequestHandle handle = {
 119         request: *request,
 120         callback: callback,
 121         success: false,
 122         completed: false
 123     };
 124
 125     handle.isotp_shims = isotp_init_shims(shims->log,
 126             shims->send_can_message,
 127             shims->set_timer);
 128     handle.isotp_shims.frame_padding = !request->no_frame_padding;
 129
 130     return handle;
 131     // TODO notes on multi frame:
 132     // TODO what are the timers for exactly?
 133     //
 134     // when sending multi frame, send 1 frame, wait for a response
 135     // if it says send all, send all right away
 136     // if it says flow control, set the time for the next send
 137     // instead of creating a timer with an async callback, add a process_handle
 138     // function that's called repeatedly in the main loop - if it's time to
 139     // send, we do it. so there's a process_handle_send and receive_can_frame
 140     // that are just called continuously from the main loop. it's a waste of a
 141     // few cpu cycles but it may be more  natural than callbacks.
 142     //
 143     // what would a timer callback look like...it would need to pass the handle
 144     // and that's all. seems like a context void* would be able to capture all
 145     // of the information but arg, memory allocation. look at how it's done in
 146     // the other library again
 147     //
 148 }
 149
 150 DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
 151         DiagnosticRequest* request, DiagnosticResponseReceived callback) {
 152     DiagnosticRequestHandle handle = generate_diagnostic_request(
 153             shims, request, callback);
 154     start_diagnostic_request(shims, &handle);
 155     return handle;
 156 }
 157
 158 DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
 159         DiagnosticPidRequestType pid_request_type, uint32_t arbitration_id,
 160         uint16_t pid, DiagnosticResponseReceived callback) {
 161     DiagnosticRequest request = {
 162         arbitration_id: arbitration_id,
 163         mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
 164         has_pid: true,
 165         pid: pid
 166     };
 167
 168     return diagnostic_request(shims, &request, callback);
 169 }
 170
 171 static bool handle_negative_response(IsoTpMessage* message,
 172         DiagnosticResponse* response, DiagnosticShims* shims) {
 173     bool response_was_negative = false;
 174     if(response->mode == NEGATIVE_RESPONSE_MODE) {
 175         response_was_negative = true;
 176         if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
 177             response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
 178         }
 179
 180         if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
 181             response->negative_response_code =
 182                     message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
 183         }
 184
 185         response->success = false;
 186         response->completed = true;
 187     }
 188     return response_was_negative;
 189 }
 190
 191 static bool handle_positive_response(DiagnosticRequestHandle* handle,
 192         IsoTpMessage* message, DiagnosticResponse* response,
 193         DiagnosticShims* shims) {
 194     bool response_was_positive = false;
 195     if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
 196         response_was_positive = true;
 197         // hide the "response" version of the mode from the user
 198         // if it matched
 199         response->mode = handle->request.mode;
 200         response->has_pid = false;
 201         if(handle->request.has_pid && message->size > 1) {
 202             response->has_pid = true;
 203             if(handle->request.pid_length == 2) {
 204                 response->pid = get_bitfield(message->payload, message->size,
 205                         PID_BYTE_INDEX * CHAR_BIT, sizeof(uint16_t) * CHAR_BIT);
 206             } else {
 207                 response->pid = message->payload[PID_BYTE_INDEX];
 208             }
 209
 210         }
 211
 212         if((!handle->request.has_pid && !response->has_pid)
 213                 || response->pid == handle->request.pid) {
 214             response->success = true;
 215             response->completed = true;
 216
 217             uint8_t payload_index = 1 + handle->request.pid_length;
 218             response->payload_length = MAX(0, message->size - payload_index);
 219             if(response->payload_length > 0) {
 220                 memcpy(response->payload, &message->payload[payload_index],
 221                         response->payload_length);
 222             }
 223         } else {
 224             response_was_positive = false;
 225         }
 226     }
 227     return response_was_positive;
 228 }
 229
 230 DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
 231         DiagnosticRequestHandle* handle, const uint32_t arbitration_id,
 232         const uint8_t data[], const uint8_t size) {
 233
 234     DiagnosticResponse response = {
 235         arbitration_id: arbitration_id,
 236         success: false,
 237         completed: false
 238     };
 239
 240     if(!handle->isotp_send_handle.completed) {
 241         isotp_continue_send(&handle->isotp_shims,
 242                 &handle->isotp_send_handle, arbitration_id, data, size);
 243     } else {
 244         uint8_t i;
 245         for(i = 0; i < handle->isotp_receive_handle_count; ++i) {
 246             IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
 247                     &handle->isotp_receive_handles[i], arbitration_id, data,
 248                     size);
 249
 250             if(message.completed) {
 251                 if(message.size > 0) {
 252                     response.mode = message.payload[0];
 253                     if(handle_negative_response(&message, &response, shims) ||
 254                             handle_positive_response(handle, &message,
 255                                 &response, shims)) {
 256                         if(shims->log != NULL) {
 257                             char response_string[128] = {0};
 258                             diagnostic_response_to_string(&response,
 259                                     response_string, sizeof(response_string));
 260                             shims->log("Diagnostic response received: %s",
 261                                     response_string);
 262                         }
 263
 264                         handle->success = true;
 265                         handle->completed = true;
 266                     }
 267                 } else {
 268                     if(shims->log != NULL) {
 269                         shims->log("Received an empty response on arb ID 0x%x",
 270                                 response.arbitration_id);
 271                     }
 272                 }
 273
 274                 if(handle->completed && handle->callback != NULL) {
 275                     handle->callback(&response);
 276                 }
 277
 278                 break;
 279             }
 280         }
 281     }
 282     return response;
 283 }
 284
 285 int diagnostic_payload_to_integer(const DiagnosticResponse* response) {
 286     return get_bitfield(response->payload, response->payload_length, 0,
 287             response->payload_length * CHAR_BIT);
 288 }
 289
 290 float diagnostic_decode_obd2_pid(const DiagnosticResponse* response) {
 291     // handles on the single number values, not the bit encoded ones
 292     switch(response->pid) {
 293         case 0xa:
 294             return response->payload[0] * 3;
 295         case 0xc:
 296             return (response->payload[0] * 256 + response->payload[1]) / 4.0;
 297         case 0xd:
 298         case 0x33:
 299         case 0xb:
 300             return response->payload[0];
 301         case 0x10:
 302             return (response->payload[0] * 256 + response->payload[1]) / 100.0;
 303         case 0x11:
 304         case 0x2f:
 305         case 0x45:
 306         case 0x4c:
 307         case 0x52:
 308         case 0x5a:
 309         case 0x4:
 310             return response->payload[0] * 100.0 / 255.0;
 311         case 0x46:
 312         case 0x5c:
 313         case 0xf:
 314         case 0x5:
 315             return response->payload[0] - 40;
 316         case 0x62:
 317             return response->payload[0] - 125;
 318         default:
 319             return diagnostic_payload_to_integer(response);
 320     }
 321 }
 322
 323 void diagnostic_response_to_string(const DiagnosticResponse* response,
 324         char* destination, size_t destination_length) {
 325     int bytes_used = snprintf(destination, destination_length,
 326             "arb_id: 0x%lx, mode: 0x%x, ",
 327             (unsigned long) response->arbitration_id,
 328             response->mode);
 329
 330     if(response->has_pid) {
 331         bytes_used += snprintf(destination + bytes_used,
 332                 destination_length - bytes_used,
 333                 "pid: 0x%x, ",
 334                 response->pid);
 335     }
 336
 337     if(!response->success) {
 338         bytes_used += snprintf(destination + bytes_used,
 339                 destination_length - bytes_used,
 340                 "nrc: 0x%x, ",
 341                 response->negative_response_code);
 342     }
 343
 344     if(response->payload_length > 0) {
 345         snprintf(destination + bytes_used, destination_length - bytes_used,
 346                 "payload: 0x%02x%02x%02x%02x%02x%02x%02x",
 347                 response->payload[0],
 348                 response->payload[1],
 349                 response->payload[2],
 350                 response->payload[3],
 351                 response->payload[4],
 352                 response->payload[5],
 353                 response->payload[6]);
 354     } else {
 355         snprintf(destination + bytes_used, destination_length - bytes_used,
 356                 "no payload");
 357     }
 358 }
 359
 360 void diagnostic_request_to_string(const DiagnosticRequest* request,
 361         char* destination, size_t destination_length) {
 362     int bytes_used = snprintf(destination, destination_length,
 363             "arb_id: 0x%lx, mode: 0x%x, ",
 364             (unsigned long) request->arbitration_id,
 365             request->mode);
 366
 367     if(request->has_pid) {
 368         bytes_used += snprintf(destination + bytes_used,
 369                 destination_length - bytes_used,
 370                 "pid: 0x%x, ",
 371                 request->pid);
 372     }
 373
 374     int remaining_space = destination_length - bytes_used;
 375     if(request->payload_length > 0) {
 376         snprintf(destination + bytes_used, remaining_space,
 377                 "payload: 0x%02x%02x%02x%02x%02x%02x%02x",
 378                 request->payload[0],
 379                 request->payload[1],
 380                 request->payload[2],
 381                 request->payload[3],
 382                 request->payload[4],
 383                 request->payload[5],
 384                 request->payload[6]);
 385     } else {
 386         snprintf(destination + bytes_used, remaining_space, "no payload");
 387     }
 388 }
 389
 390 bool diagnostic_request_equals(const DiagnosticRequest* ours,
 391         const DiagnosticRequest* theirs) {
 392     bool equals = ours->arbitration_id == theirs->arbitration_id &&
 393         ours->mode == theirs->mode;
 394     equals &= ours->has_pid == theirs->has_pid;
 395     equals &= ours->pid == theirs->pid;
 396     return equals;
 397 }