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
  91     handle.isotp_send_handle = isotp_send(&handle.isotp_shims,
  92             request->arbitration_id, payload,
  93             1 + request->payload_length + request->pid_length,
  94             NULL);
  95     if(shims->log != NULL) {
  96         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",
  97                 request->arbitration_id,
  98                 request->mode,
  99                 request->pid,
 100                 request->payload[0],
 101                 request->payload[1],
 102                 request->payload[2],
 103                 request->payload[3],
 104                 request->payload[4],
 105                 request->payload[5],
 106                 request->payload[6],
 107                 request->payload_length);
 108     }
 109
 110     setup_receive_handle(&handle);
 111
 112     // TODO notes on multi frame:
 113     // TODO what are the timers for exactly?
 114     //
 115     // when sending multi frame, send 1 frame, wait for a response
 116     // if it says send all, send all right away
 117     // if it says flow control, set the time for the next send
 118     // instead of creating a timer with an async callback, add a process_handle
 119     // function that's called repeatedly in the main loop - if it's time to
 120     // send, we do it. so there's a process_handle_send and receive_can_frame
 121     // that are just called continuously from the main loop. it's a waste of a
 122     // few cpu cycles but it may be more  natural than callbacks.
 123     //
 124     // what woudl a timer callback look like...it would need to pass the handle
 125     // and that's all. seems like a context void* would be able to capture all
 126     // of the information but arg, memory allocation. look at how it's done in
 127     // the other library again
 128     //
 129     return handle;
 130 }
 131
 132 DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
 133         DiagnosticPidRequestType pid_request_type, uint16_t arbitration_id,
 134         uint16_t pid, DiagnosticResponseReceived callback) {
 135     DiagnosticRequest request = {
 136         arbitration_id: arbitration_id,
 137         mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
 138         has_pid: true,
 139         pid: pid
 140     };
 141
 142     return diagnostic_request(shims, &request, callback);
 143 }
 144
 145 static bool handle_negative_response(IsoTpMessage* message,
 146         DiagnosticResponse* response, DiagnosticShims* shims) {
 147     bool response_was_negative = false;
 148     if(response->mode == NEGATIVE_RESPONSE_MODE) {
 149         response_was_negative = true;
 150         if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
 151             response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
 152         }
 153
 154         if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
 155             response->negative_response_code =
 156                     message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
 157         }
 158
 159         response->success = false;
 160         response->completed = true;
 161     }
 162     return response_was_negative;
 163 }
 164
 165 static bool handle_positive_response(DiagnosticRequestHandle* handle,
 166         IsoTpMessage* message, DiagnosticResponse* response,
 167         DiagnosticShims* shims) {
 168     bool response_was_positive = false;
 169     if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
 170         response_was_positive = true;
 171         // hide the "response" version of the mode from the user
 172         // if it matched
 173         response->mode = handle->request.mode;
 174         response->has_pid = false;
 175         if(handle->request.has_pid && message->size > 1) {
 176             response->has_pid = true;
 177             if(handle->request.pid_length == 2) {
 178                 response->pid = get_bitfield(message->payload, message->size,
 179                         PID_BYTE_INDEX * CHAR_BIT, sizeof(uint16_t) * CHAR_BIT);
 180             } else {
 181                 response->pid = message->payload[PID_BYTE_INDEX];
 182             }
 183
 184         }
 185
 186         uint8_t payload_index = 1 + handle->request.pid_length;
 187         response->payload_length = MAX(0, message->size - payload_index);
 188         if(response->payload_length > 0) {
 189             memcpy(response->payload, &message->payload[payload_index],
 190                     response->payload_length);
 191         }
 192
 193         if((!handle->request.has_pid && !response->has_pid)
 194                 || response->pid == handle->request.pid) {
 195             response->success = true;
 196             response->completed = true;
 197         } else {
 198             response_was_positive = false;
 199         }
 200     }
 201     return response_was_positive;
 202 }
 203
 204 DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
 205         DiagnosticRequestHandle* handle, const uint16_t arbitration_id,
 206         const uint8_t data[], const uint8_t size) {
 207
 208     DiagnosticResponse response = {
 209         arbitration_id: arbitration_id,
 210         success: false,
 211         completed: false
 212     };
 213
 214     if(!handle->isotp_send_handle.completed) {
 215         isotp_continue_send(&handle->isotp_shims,
 216                 &handle->isotp_send_handle, arbitration_id, data, size);
 217     } else {
 218         uint8_t i;
 219         for(i = 0; i < handle->isotp_receive_handle_count; ++i) {
 220             IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
 221                     &handle->isotp_receive_handles[i], arbitration_id, data,
 222                     size);
 223
 224             if(message.completed) {
 225                 if(message.size > 0) {
 226                     response.mode = message.payload[0];
 227                     if(handle_negative_response(&message, &response, shims)) {
 228                         shims->log("Received a negative response to mode 0x%x on arb ID 0x%x",
 229                                 response.mode, response.arbitration_id);
 230                         handle->success = true;
 231                         handle->completed = true;
 232                     } else if(handle_positive_response(handle, &message,
 233                                 &response, shims)) {
 234                         shims->log("Received a positive mode 0x%x response on arb ID 0x%x",
 235                                 response.mode, response.arbitration_id);
 236                         handle->success = true;
 237                         handle->completed = true;
 238                     } else {
 239                         shims->log("Response was for a mode 0x%x request (pid 0x%x), not our mode 0x%x request (pid 0x%x)",
 240                                 MAX(0, response.mode - MODE_RESPONSE_OFFSET),
 241                                 response.pid, handle->request.mode,
 242                                 handle->request.pid);
 243                     }
 244                 } else {
 245                     shims->log("Received an empty response on arb ID 0x%x",
 246                             response.arbitration_id);
 247                 }
 248
 249                 if(handle->completed && handle->callback != NULL) {
 250                     handle->callback(&response);
 251                 }
 252
 253                 break;
 254             }
 255         }
 256     }
 257     return response;
 258 }
 259
 260 float diagnostic_payload_to_float(const DiagnosticResponse* response) {
 261     return bitfield_parse_float(response->payload,
 262             response->payload_length, 0,
 263             response->payload_length * CHAR_BIT, 1.0, 0);
 264 }
 265
 266 /* Public:
 267  *
 268  * Functions pulled from http://en.wikipedia.org/wiki/OBD-II_PIDs#Mode_01
 269  */
 270 float diagnostic_decode_obd2_pid(const DiagnosticResponse* response) {
 271     // handles on the single number values, not the bit encoded ones
 272     switch(response->pid) {
 273         case 0xa:
 274             return response->payload[0] * 3;
 275         case 0xc:
 276             return (response->payload[0] * 256 + response->payload[1]) / 4.0;
 277         case 0xd:
 278         case 0x33:
 279         case 0xb:
 280             return response->payload[0];
 281         case 0x10:
 282             return (response->payload[0] * 256 + response->payload[1]) / 100.0;
 283         case 0x11:
 284         case 0x2f:
 285         case 0x45:
 286         case 0x4c:
 287         case 0x52:
 288         case 0x5a:
 289         case 0x4:
 290             return response->payload[0] * 100.0 / 255.0;
 291         case 0x46:
 292         case 0x5c:
 293         case 0xf:
 294         case 0x5:
 295             return response->payload[0] - 40;
 296         case 0x62:
 297             return response->payload[0] - 125;
 298         default:
 299             return 0;
 300     }
 301 }