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 > 10) {
  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(shims->log != NULL) {
  88         char request_string[128] = {0};
  89         diagnostic_request_to_string(&handle->request, request_string,
  90                 sizeof(request_string));
  91         shims->log("Sending diagnostic request: %s", request_string);
  92     }
  93 }
  94
  95 void start_diagnostic_request(DiagnosticShims* shims,
  96         DiagnosticRequestHandle* handle) {
  97     handle->success = false;
  98     handle->completed = false;
  99     send_diagnostic_request(shims, handle);
 100     setup_receive_handle(handle);
 101 }
 102
 103 DiagnosticRequestHandle generate_diagnostic_request(DiagnosticShims* shims,
 104         DiagnosticRequest* request, DiagnosticResponseReceived callback) {
 105     DiagnosticRequestHandle handle = {
 106         request: *request,
 107         callback: callback,
 108         success: false,
 109         completed: false
 110     };
 111
 112     handle.isotp_shims = isotp_init_shims(shims->log,
 113             shims->send_can_message,
 114             shims->set_timer);
 115     handle.isotp_shims.frame_padding = !request->no_frame_padding;
 116
 117     return handle;
 118     // TODO notes on multi frame:
 119     // TODO what are the timers for exactly?
 120     //
 121     // when sending multi frame, send 1 frame, wait for a response
 122     // if it says send all, send all right away
 123     // if it says flow control, set the time for the next send
 124     // instead of creating a timer with an async callback, add a process_handle
 125     // function that's called repeatedly in the main loop - if it's time to
 126     // send, we do it. so there's a process_handle_send and receive_can_frame
 127     // that are just called continuously from the main loop. it's a waste of a
 128     // few cpu cycles but it may be more  natural than callbacks.
 129     //
 130     // what would a timer callback look like...it would need to pass the handle
 131     // and that's all. seems like a context void* would be able to capture all
 132     // of the information but arg, memory allocation. look at how it's done in
 133     // the other library again
 134     //
 135 }
 136
 137 DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
 138         DiagnosticRequest* request, DiagnosticResponseReceived callback) {
 139     DiagnosticRequestHandle handle = generate_diagnostic_request(
 140             shims, request, callback);
 141     start_diagnostic_request(shims, &handle);
 142     return handle;
 143 }
 144
 145 DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
 146         DiagnosticPidRequestType pid_request_type, uint32_t arbitration_id,
 147         uint16_t pid, DiagnosticResponseReceived callback) {
 148     DiagnosticRequest request = {
 149         arbitration_id: arbitration_id,
 150         mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
 151         has_pid: true,
 152         pid: pid
 153     };
 154
 155     return diagnostic_request(shims, &request, callback);
 156 }
 157
 158 static bool handle_negative_response(IsoTpMessage* message,
 159         DiagnosticResponse* response, DiagnosticShims* shims) {
 160     bool response_was_negative = false;
 161     if(response->mode == NEGATIVE_RESPONSE_MODE) {
 162         response_was_negative = true;
 163         if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
 164             response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
 165         }
 166
 167         if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
 168             response->negative_response_code =
 169                     message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
 170         }
 171
 172         response->success = false;
 173         response->completed = true;
 174     }
 175     return response_was_negative;
 176 }
 177
 178 static bool handle_positive_response(DiagnosticRequestHandle* handle,
 179         IsoTpMessage* message, DiagnosticResponse* response,
 180         DiagnosticShims* shims) {
 181     bool response_was_positive = false;
 182     if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
 183         response_was_positive = true;
 184         // hide the "response" version of the mode from the user
 185         // if it matched
 186         response->mode = handle->request.mode;
 187         response->has_pid = false;
 188         if(handle->request.has_pid && message->size > 1) {
 189             response->has_pid = true;
 190             if(handle->request.pid_length == 2) {
 191                 response->pid = get_bitfield(message->payload, message->size,
 192                         PID_BYTE_INDEX * CHAR_BIT, sizeof(uint16_t) * CHAR_BIT);
 193             } else {
 194                 response->pid = message->payload[PID_BYTE_INDEX];
 195             }
 196
 197         }
 198
 199         if((!handle->request.has_pid && !response->has_pid)
 200                 || response->pid == handle->request.pid) {
 201             response->success = true;
 202             response->completed = true;
 203
 204             uint8_t payload_index = 1 + handle->request.pid_length;
 205             response->payload_length = MAX(0, message->size - payload_index);
 206             if(response->payload_length > 0) {
 207                 memcpy(response->payload, &message->payload[payload_index],
 208                         response->payload_length);
 209             }
 210         } else {
 211             response_was_positive = false;
 212         }
 213     }
 214     return response_was_positive;
 215 }
 216
 217 DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
 218         DiagnosticRequestHandle* handle, const uint32_t arbitration_id,
 219         const uint8_t data[], const uint8_t size) {
 220
 221     DiagnosticResponse response = {
 222         arbitration_id: arbitration_id,
 223         success: false,
 224         completed: false
 225     };
 226
 227     if(!handle->isotp_send_handle.completed) {
 228         isotp_continue_send(&handle->isotp_shims,
 229                 &handle->isotp_send_handle, arbitration_id, data, size);
 230     } else {
 231         uint8_t i;
 232         for(i = 0; i < handle->isotp_receive_handle_count; ++i) {
 233             IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
 234                     &handle->isotp_receive_handles[i], arbitration_id, data,
 235                     size);
 236
 237             if(message.completed) {
 238                 if(message.size > 0) {
 239                     response.mode = message.payload[0];
 240                     if(handle_negative_response(&message, &response, shims) ||
 241                             handle_positive_response(handle, &message,
 242                                 &response, shims)) {
 243                         if(shims->log != NULL) {
 244                             char response_string[128] = {0};
 245                             diagnostic_response_to_string(&response,
 246                                     response_string, sizeof(response_string));
 247                             shims->log("Diagnostic response received: %s",
 248                                     response_string);
 249                         }
 250
 251                         handle->success = true;
 252                         handle->completed = true;
 253                     }
 254                 } else {
 255                     if(shims->log != NULL) {
 256                         shims->log("Received an empty response on arb ID 0x%x",
 257                                 response.arbitration_id);
 258                     }
 259                 }
 260
 261                 if(handle->completed && handle->callback != NULL) {
 262                     handle->callback(&response);
 263                 }
 264
 265                 break;
 266             }
 267         }
 268     }
 269     return response;
 270 }
 271
 272 int diagnostic_payload_to_integer(const DiagnosticResponse* response) {
 273     return get_bitfield(response->payload, response->payload_length, 0,
 274             response->payload_length * CHAR_BIT);
 275 }
 276
 277 float diagnostic_decode_obd2_pid(const DiagnosticResponse* response) {
 278     // handles on the single number values, not the bit encoded ones
 279     switch(response->pid) {
 280         case 0xa:
 281             return response->payload[0] * 3;
 282         case 0xc:
 283             return (response->payload[0] * 256 + response->payload[1]) / 4.0;
 284         case 0xd:
 285         case 0x33:
 286         case 0xb:
 287             return response->payload[0];
 288         case 0x10:
 289             return (response->payload[0] * 256 + response->payload[1]) / 100.0;
 290         case 0x11:
 291         case 0x2f:
 292         case 0x45:
 293         case 0x4c:
 294         case 0x52:
 295         case 0x5a:
 296         case 0x4:
 297             return response->payload[0] * 100.0 / 255.0;
 298         case 0x46:
 299         case 0x5c:
 300         case 0xf:
 301         case 0x5:
 302             return response->payload[0] - 40;
 303         case 0x62:
 304             return response->payload[0] - 125;
 305         default:
 306             return 0;
 307     }
 308 }
 309
 310 void diagnostic_response_to_string(const DiagnosticResponse* response,
 311         char* destination, size_t destination_length) {
 312     int bytes_used = snprintf(destination, destination_length,
 313             "arb_id: 0x%" SCNd32 ", mode: 0x%x, ",
 314             response->arbitration_id,
 315             response->mode);
 316
 317     if(response->has_pid) {
 318         bytes_used += snprintf(destination + bytes_used,
 319                 destination_length - bytes_used,
 320                 "pid: 0x%x, ",
 321                 response->pid);
 322     }
 323
 324     if(!response->success) {
 325         bytes_used += snprintf(destination + bytes_used,
 326                 destination_length - bytes_used,
 327                 "nrc: 0x%x, ",
 328                 response->negative_response_code);
 329     }
 330
 331     if(response->payload_length > 0) {
 332         snprintf(destination + bytes_used, destination_length - bytes_used,
 333                 "payload: 0x%02x%02x%02x%02x%02x%02x%02x",
 334                 response->payload[0],
 335                 response->payload[1],
 336                 response->payload[2],
 337                 response->payload[3],
 338                 response->payload[4],
 339                 response->payload[5],
 340                 response->payload[6]);
 341     } else {
 342         snprintf(destination + bytes_used, destination_length - bytes_used,
 343                 "no payload");
 344     }
 345 }
 346
 347 void diagnostic_request_to_string(const DiagnosticRequest* request,
 348         char* destination, size_t destination_length) {
 349     int bytes_used = snprintf(destination, destination_length,
 350             "arb_id: 0x%" SCNd32 ", mode: 0x%x, ",
 351             request->arbitration_id,
 352             request->mode);
 353
 354     if(request->has_pid) {
 355         bytes_used += snprintf(destination + bytes_used,
 356                 destination_length - bytes_used,
 357                 "pid: 0x%x, ",
 358                 request->pid);
 359     }
 360
 361     int remaining_space = destination_length - bytes_used;
 362     if(request->payload_length > 0) {
 363         snprintf(destination + bytes_used, remaining_space,
 364                 "payload: 0x%02x%02x%02x%02x%02x%02x%02x",
 365                 request->payload[0],
 366                 request->payload[1],
 367                 request->payload[2],
 368                 request->payload[3],
 369                 request->payload[4],
 370                 request->payload[5],
 371                 request->payload[6]);
 372     } else {
 373         snprintf(destination + bytes_used, remaining_space, "no payload");
 374     }
 375 }
 376
 377 bool diagnostic_request_equals(const DiagnosticRequest* ours,
 378         const DiagnosticRequest* theirs) {
 379     bool equals = ours->arbitration_id == theirs->arbitration_id &&
 380         ours->mode == theirs->mode;
 381     equals &= ours->has_pid == theirs->has_pid;
 382     equals &= ours->pid == theirs->pid;
 383     return equals;
 384 }