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