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 DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
  53         DiagnosticRequest* request, DiagnosticResponseReceived callback) {
  54     DiagnosticRequestHandle handle = {
  55         request: *request,
  56         callback: callback,
  57         success: false,
  58         completed: false
  59     };
  60
  61     uint8_t payload[MAX_DIAGNOSTIC_PAYLOAD_SIZE] = {0};
  62     payload[MODE_BYTE_INDEX] = request->mode;
  63     if(request->pid_length > 0) {
  64         set_bitfield(request->pid, PID_BYTE_INDEX * CHAR_BIT,
  65                 request->pid_length * CHAR_BIT, payload, sizeof(payload));
  66     }
  67     if(request->payload_length > 0) {
  68         memcpy(&payload[PID_BYTE_INDEX + request->pid_length],
  69                 request->payload, request->payload_length);
  70     }
  71
  72     handle.isotp_shims = isotp_init_shims(shims->log,
  73             shims->send_can_message,
  74             shims->set_timer);
  75
  76     handle.isotp_send_handle = isotp_send(&handle.isotp_shims,
  77             request->arbitration_id, payload,
  78             1 + request->payload_length + request->pid_length,
  79             NULL);
  80     if(shims->log != NULL) {
  81         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",
  82                 request->arbitration_id,
  83                 request->mode,
  84                 request->pid,
  85                 request->payload[0],
  86                 request->payload[1],
  87                 request->payload[2],
  88                 request->payload[3],
  89                 request->payload[4],
  90                 request->payload[5],
  91                 request->payload[6],
  92                 request->payload_length);
  93     }
  94
  95     setup_receive_handle(&handle);
  96
  97     // TODO notes on multi frame:
  98     // TODO what are the timers for exactly?
  99     //
 100     // when sending multi frame, send 1 frame, wait for a response
 101     // if it says send all, send all right away
 102     // if it says flow control, set the time for the next send
 103     // instead of creating a timer with an async callback, add a process_handle
 104     // function that's called repeatedly in the main loop - if it's time to
 105     // send, we do it. so there's a process_handle_send and receive_can_frame
 106     // that are just called continuously from the main loop. it's a waste of a
 107     // few cpu cycles but it may be more  natural than callbacks.
 108     //
 109     // what woudl a timer callback look like...it would need to pass the handle
 110     // and that's all. seems like a context void* would be able to capture all
 111     // of the information but arg, memory allocation. look at how it's done in
 112     // the other library again
 113     //
 114     return handle;
 115 }
 116
 117 DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
 118         DiagnosticPidRequestType pid_request_type, uint16_t arbitration_id,
 119         uint16_t pid, DiagnosticResponseReceived callback) {
 120     DiagnosticRequest request = {
 121         arbitration_id: arbitration_id,
 122         mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
 123         pid: pid,
 124         pid_length: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 1 : 2
 125     };
 126
 127     return diagnostic_request(shims, &request, callback);
 128 }
 129
 130 static bool handle_negative_response(IsoTpMessage* message,
 131         DiagnosticResponse* response, DiagnosticShims* shims) {
 132     bool response_was_negative = false;
 133     if(response->mode == NEGATIVE_RESPONSE_MODE) {
 134         response_was_negative = true;
 135         if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
 136             response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
 137         }
 138
 139         if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
 140             response->negative_response_code =
 141                     message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
 142         }
 143
 144         response->success = false;
 145         response->completed = true;
 146     }
 147     return response_was_negative;
 148 }
 149
 150 static bool handle_positive_response(DiagnosticRequestHandle* handle,
 151         IsoTpMessage* message, DiagnosticResponse* response,
 152         DiagnosticShims* shims) {
 153     bool response_was_positive = false;
 154     if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
 155         response_was_positive = true;
 156         // hide the "response" version of the mode from the user
 157         // if it matched
 158         response->mode = handle->request.mode;
 159         response->has_pid = false;
 160         if(handle->request.pid_length > 0 && message->size > 1) {
 161             response->has_pid = true;
 162             if(handle->request.pid_length == 2) {
 163                 response->pid = get_bitfield(message->payload, message->size,
 164                         PID_BYTE_INDEX * CHAR_BIT, sizeof(uint16_t) * CHAR_BIT);
 165             } else {
 166                 response->pid = message->payload[PID_BYTE_INDEX];
 167             }
 168
 169         }
 170
 171         uint8_t payload_index = 1 + handle->request.pid_length;
 172         response->payload_length = MAX(0, message->size - payload_index);
 173         if(response->payload_length > 0) {
 174             memcpy(response->payload, &message->payload[payload_index],
 175                     response->payload_length);
 176         }
 177
 178         if((handle->request.pid_length == 0 && !response->has_pid)
 179                 || response->pid == handle->request.pid) {
 180             response->success = true;
 181             response->completed = true;
 182         } else {
 183             response_was_positive = false;
 184         }
 185     }
 186     return response_was_positive;
 187 }
 188
 189 DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
 190         DiagnosticRequestHandle* handle, const uint16_t arbitration_id,
 191         const uint8_t data[], const uint8_t size) {
 192
 193     DiagnosticResponse response = {
 194         arbitration_id: arbitration_id,
 195         success: false,
 196         completed: false
 197     };
 198
 199     if(!handle->isotp_send_handle.completed) {
 200         isotp_continue_send(&handle->isotp_shims,
 201                 &handle->isotp_send_handle, arbitration_id, data, size);
 202     } else {
 203         uint8_t i;
 204         for(i = 0; i < handle->isotp_receive_handle_count; ++i) {
 205             IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
 206                     &handle->isotp_receive_handles[i], arbitration_id, data,
 207                     size);
 208
 209             if(message.completed) {
 210                 if(message.size > 0) {
 211                     response.mode = message.payload[0];
 212                     if(handle_negative_response(&message, &response, shims)) {
 213                         shims->log("Received a negative response to mode %d on arb ID 0x%x",
 214                                 response.mode, response.arbitration_id);
 215                         handle->success = true;
 216                         handle->completed = true;
 217                     } else if(handle_positive_response(handle, &message,
 218                                 &response, shims)) {
 219                         shims->log("Received a positive mode %d response on arb ID 0x%x",
 220                                 response.mode, response.arbitration_id);
 221                         handle->success = true;
 222                         handle->completed = true;
 223                     } else {
 224                         shims->log("Response was for a mode 0x%x request (pid 0x%x), not our mode 0x%x request (pid 0x%x)",
 225                                 MAX(0, response.mode - MODE_RESPONSE_OFFSET),
 226                                 response.pid, handle->request.mode,
 227                                 handle->request.pid);
 228                         // TODO just leave handles open until the user decides
 229                         // to be done with it - keep a count of valid responses
 230                         // received.
 231                     }
 232                 } else {
 233                     shims->log("Received an empty response on arb ID 0x%x",
 234                             response.arbitration_id);
 235                 }
 236
 237                 if(handle->completed && handle->callback != NULL) {
 238                     handle->callback(&response);
 239                 }
 240
 241                 // TODO as of now we're completing the handle as soon as one
 242                 // broadcast response is received....need to hang on for 100ms
 243                 break;
 244             }
 245         }
 246     }
 247     return response;
 248 }
 249
 250 float diagnostic_payload_to_float(const DiagnosticResponse* response) {
 251     return bitfield_parse_float(response->payload,
 252             response->payload_length, 0,
 253             response->payload_length * CHAR_BIT, 1.0, 0);
 254 }