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         uint16_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 DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
  65         DiagnosticRequest* request, DiagnosticResponseReceived callback) {
  66     DiagnosticRequestHandle handle = {
  67         request: *request,
  68         callback: callback,
  69         success: false,
  70         completed: false
  71     };
  72
  73     uint8_t payload[MAX_DIAGNOSTIC_PAYLOAD_SIZE] = {0};
  74     payload[MODE_BYTE_INDEX] = request->mode;
  75     if(request->has_pid) {
  76         request->pid_length = autoset_pid_length(request->mode,
  77                 request->pid, request->pid_length);
  78         handle.request.pid_length = request->pid_length;
  79         set_bitfield(request->pid, PID_BYTE_INDEX * CHAR_BIT,
  80                 request->pid_length * CHAR_BIT, payload, sizeof(payload));
  81     }
  82     if(request->payload_length > 0) {
  83         memcpy(&payload[PID_BYTE_INDEX + request->pid_length],
  84                 request->payload, request->payload_length);
  85     }
  86
  87     handle.isotp_shims = isotp_init_shims(shims->log,
  88             shims->send_can_message,
  89             shims->set_timer);
  90     handle.isotp_shims.frame_padding = !request->no_frame_padding;
  91
  92     handle.isotp_send_handle = isotp_send(&handle.isotp_shims,
  93             request->arbitration_id, payload,
  94             1 + request->payload_length + request->pid_length,
  95             NULL);
  96     if(shims->log != NULL) {
  97         char request_string[128] = {0};
  98         diagnostic_request_to_string(request, request_string, sizeof(request_string));
  99         shims->log("Sending diagnostic request: %s", request_string);
 100     }
 101
 102     setup_receive_handle(&handle);
 103
 104     // TODO notes on multi frame:
 105     // TODO what are the timers for exactly?
 106     //
 107     // when sending multi frame, send 1 frame, wait for a response
 108     // if it says send all, send all right away
 109     // if it says flow control, set the time for the next send
 110     // instead of creating a timer with an async callback, add a process_handle
 111     // function that's called repeatedly in the main loop - if it's time to
 112     // send, we do it. so there's a process_handle_send and receive_can_frame
 113     // that are just called continuously from the main loop. it's a waste of a
 114     // few cpu cycles but it may be more  natural than callbacks.
 115     //
 116     // what would a timer callback look like...it would need to pass the handle
 117     // and that's all. seems like a context void* would be able to capture all
 118     // of the information but arg, memory allocation. look at how it's done in
 119     // the other library again
 120     //
 121     return handle;
 122 }
 123
 124 DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
 125         DiagnosticPidRequestType pid_request_type, uint16_t arbitration_id,
 126         uint16_t pid, DiagnosticResponseReceived callback) {
 127     DiagnosticRequest request = {
 128         arbitration_id: arbitration_id,
 129         mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
 130         has_pid: true,
 131         pid: pid
 132     };
 133
 134     return diagnostic_request(shims, &request, callback);
 135 }
 136
 137 static bool handle_negative_response(IsoTpMessage* message,
 138         DiagnosticResponse* response, DiagnosticShims* shims) {
 139     bool response_was_negative = false;
 140     if(response->mode == NEGATIVE_RESPONSE_MODE) {
 141         response_was_negative = true;
 142         if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
 143             response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
 144         }
 145
 146         if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
 147             response->negative_response_code =
 148                     message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
 149         }
 150
 151         response->success = false;
 152         response->completed = true;
 153     }
 154     return response_was_negative;
 155 }
 156
 157 static bool handle_positive_response(DiagnosticRequestHandle* handle,
 158         IsoTpMessage* message, DiagnosticResponse* response,
 159         DiagnosticShims* shims) {
 160     bool response_was_positive = false;
 161     if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
 162         response_was_positive = true;
 163         // hide the "response" version of the mode from the user
 164         // if it matched
 165         response->mode = handle->request.mode;
 166         response->has_pid = false;
 167         if(handle->request.has_pid && message->size > 1) {
 168             response->has_pid = true;
 169             if(handle->request.pid_length == 2) {
 170                 response->pid = get_bitfield(message->payload, message->size,
 171                         PID_BYTE_INDEX * CHAR_BIT, sizeof(uint16_t) * CHAR_BIT);
 172             } else {
 173                 response->pid = message->payload[PID_BYTE_INDEX];
 174             }
 175
 176         }
 177
 178         uint8_t payload_index = 1 + handle->request.pid_length;
 179         response->payload_length = MAX(0, message->size - payload_index);
 180         if(response->payload_length > 0) {
 181             memcpy(response->payload, &message->payload[payload_index],
 182                     response->payload_length);
 183         }
 184
 185         if((!handle->request.has_pid && !response->has_pid)
 186                 || response->pid == handle->request.pid) {
 187             response->success = true;
 188             response->completed = true;
 189         } else {
 190             response_was_positive = false;
 191         }
 192     }
 193     return response_was_positive;
 194 }
 195
 196 DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
 197         DiagnosticRequestHandle* handle, const uint16_t arbitration_id,
 198         const uint8_t data[], const uint8_t size) {
 199
 200     DiagnosticResponse response = {
 201         arbitration_id: arbitration_id,
 202         success: false,
 203         completed: false
 204     };
 205
 206     if(!handle->isotp_send_handle.completed) {
 207         isotp_continue_send(&handle->isotp_shims,
 208                 &handle->isotp_send_handle, arbitration_id, data, size);
 209     } else {
 210         uint8_t i;
 211         for(i = 0; i < handle->isotp_receive_handle_count; ++i) {
 212             IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
 213                     &handle->isotp_receive_handles[i], arbitration_id, data,
 214                     size);
 215
 216             if(message.completed) {
 217                 if(message.size > 0) {
 218                     response.mode = message.payload[0];
 219                     if(handle_negative_response(&message, &response, shims)) {
 220                         if(shims->log != NULL) {
 221                             char response_string[128] = {0};
 222                             diagnostic_response_to_string(&response, response_string, sizeof(response_string));
 223                             shims->log("Received a negative response: %s", response_string);
 224                         }
 225
 226                         handle->success = true;
 227                         handle->completed = true;
 228                     } else if(handle_positive_response(handle, &message,
 229                                 &response, shims)) {
 230                         if(shims->log != NULL) {
 231                             char response_string[128] = {0};
 232                             diagnostic_response_to_string(&response, response_string, sizeof(response_string));
 233                             shims->log("Received a positive response: %s", response_string);
 234                         }
 235
 236                         handle->success = true;
 237                         handle->completed = true;
 238                     } else {
 239                         if(shims->log != NULL) {
 240                             char response_string[128] = {0};
 241                             diagnostic_response_to_string(&response, response_string, sizeof(response_string));
 242                             shims->log("Expected a mode 0x%x response to pid 0x%x but received: %s",
 243                                     MAX(0, response.mode - MODE_RESPONSE_OFFSET),
 244                                     response.pid,
 245                                     response_string);
 246                         }
 247                     }
 248                 } else {
 249                     if(shims->log != NULL) {
 250                         shims->log("Received an empty response on arb ID 0x%x",
 251                                 response.arbitration_id);
 252                     }
 253                 }
 254
 255                 if(handle->completed && handle->callback != NULL) {
 256                     handle->callback(&response);
 257                 }
 258
 259                 break;
 260             }
 261         }
 262     }
 263     return response;
 264 }
 265
 266 int diagnostic_payload_to_integer(const DiagnosticResponse* response) {
 267     return get_bitfield(response->payload, response->payload_length, 0,
 268             response->payload_length * CHAR_BIT);
 269 }
 270
 271 float diagnostic_decode_obd2_pid(const DiagnosticResponse* response) {
 272     // handles on the single number values, not the bit encoded ones
 273     switch(response->pid) {
 274         case 0xa:
 275             return response->payload[0] * 3;
 276         case 0xc:
 277             return (response->payload[0] * 256 + response->payload[1]) / 4.0;
 278         case 0xd:
 279         case 0x33:
 280         case 0xb:
 281             return response->payload[0];
 282         case 0x10:
 283             return (response->payload[0] * 256 + response->payload[1]) / 100.0;
 284         case 0x11:
 285         case 0x2f:
 286         case 0x45:
 287         case 0x4c:
 288         case 0x52:
 289         case 0x5a:
 290         case 0x4:
 291             return response->payload[0] * 100.0 / 255.0;
 292         case 0x46:
 293         case 0x5c:
 294         case 0xf:
 295         case 0x5:
 296             return response->payload[0] - 40;
 297         case 0x62:
 298             return response->payload[0] - 125;
 299         default:
 300             return 0;
 301     }
 302 }
 303
 304 void diagnostic_response_to_string(const DiagnosticResponse* response,
 305         char* destination, size_t destination_length) {
 306     int bytes_used = snprintf(destination, destination_length,
 307             "arb_id: 0x%02x, mode: 0x%x, ",
 308             response->arbitration_id,
 309             response->mode);
 310
 311     if(response->has_pid) {
 312         bytes_used += snprintf(destination + bytes_used,
 313                 destination_length - bytes_used,
 314                 "pid: 0x%x, ",
 315                 response->pid);
 316     }
 317
 318     if(!response->success) {
 319         bytes_used += snprintf(destination + bytes_used,
 320                 destination_length - bytes_used,
 321                 "nrc: 0x%x, ",
 322                 response->negative_response_code);
 323     }
 324
 325     if(response->payload_length > 0) {
 326         snprintf(destination + bytes_used, destination_length - bytes_used,
 327                 "payload: 0x%02x%02x%02x%02x%02x%02x%02x",
 328                 response->payload[0],
 329                 response->payload[1],
 330                 response->payload[2],
 331                 response->payload[3],
 332                 response->payload[4],
 333                 response->payload[5],
 334                 response->payload[6]);
 335     } else {
 336         snprintf(destination + bytes_used, destination_length - bytes_used,
 337                 "no payload");
 338     }
 339 }
 340
 341 void diagnostic_request_to_string(const DiagnosticRequest* request,
 342         char* destination, size_t destination_length) {
 343     int bytes_used = snprintf(destination, destination_length,
 344             "arb_id: 0x%02x, mode: 0x%x, ",
 345             request->arbitration_id,
 346             request->mode);
 347
 348     if(request->has_pid) {
 349         bytes_used += snprintf(destination + bytes_used,
 350                 destination_length - bytes_used,
 351                 "pid: 0x%x, ",
 352                 request->pid);
 353     }
 354
 355     int remaining_space = destination_length - bytes_used;
 356     if(request->payload_length > 0) {
 357         snprintf(destination + bytes_used, remaining_space,
 358                 "payload: 0x%02x%02x%02x%02x%02x%02x%02x",
 359                 request->payload[0],
 360                 request->payload[1],
 361                 request->payload[2],
 362                 request->payload[3],
 363                 request->payload[4],
 364                 request->payload[5],
 365                 request->payload[6]);
 366     } else {
 367         snprintf(destination + bytes_used, remaining_space, "no payload");
 368     }
 369 }
 370