src/isotp/isotp.c

   1 #include <isotp/isotp.h>
   2 #include <isotp/receive.h>
   3 #include <bitfield/bitfield.h>
   4
   5 const uint16_t MAX_ISO_TP_MESSAGE_SIZE = 4096;
   6 const uint16_t MAX_CAN_FRAME_SIZE = 8;
   7 const uint8_t ISO_TP_DEFAULT_RESPONSE_TIMEOUT = 100;
   8 const bool ISO_TP_DEFAULT_FRAME_PADDING_STATUS = true;
   9
  10 /* void isotp_set_timeout(IsoTpHandler* handler, uint16_t timeout_ms) { */
  11     /* handler->timeout_ms = timeout_ms; */
  12 /* } */
  13
  14 IsoTpShims isotp_init_shims(LogShim log, SendCanMessageShim send_can_message,
  15         SetTimerShim set_timer) {
  16     IsoTpShims shims = {
  17         log: log,
  18         send_can_message: send_can_message,
  19         set_timer: set_timer
  20     };
  21     return shims;
  22 }
  23
  24 void isotp_message_to_string(const IsoTpMessage* message, char* destination,
  25         size_t destination_length) {
  26     char payload_string[message->size * 2 + 1];
  27     for(int i = 0; i < message->size; i++) {
  28         // TODO, bah this isn't working because snprintf hits the NULL char that
  29         // it wrote the last time and stops cold
  30         snprintf(&payload_string[i * 2], 2, "%02x", message->payload[i]);
  31     }
  32     snprintf(destination, destination_length, "ID: 0x%02x, Payload: 0x%s",
  33             message->arbitration_id, payload_string);
  34 }
  35
  36 bool isotp_receive_can_frame(IsoTpShims* shims, IsoTpHandle* handle,
  37         const uint16_t arbitration_id, const uint8_t data[],
  38         const uint8_t data_length) {
  39     bool message_completed = false;
  40
  41     if(data_length < 1) {
  42         return message_completed;
  43     }
  44
  45     if(handle->type == ISOTP_HANDLE_RECEIVING) {
  46         if(handle->receive_handle.arbitration_id != arbitration_id) {
  47             return message_completed;
  48         }
  49     } else if(handle->type == ISOTP_HANDLE_SENDING) {
  50         if(handle->send_handle.receiving_arbitration_id != arbitration_id) {
  51             return message_completed;
  52         }
  53     } else {
  54         shims->log("The ISO-TP handle is corrupt");
  55         return message_completed;
  56     }
  57
  58     IsoTpProtocolControlInformation pci = (IsoTpProtocolControlInformation)
  59             get_nibble(data, data_length, 0);
  60
  61     uint8_t payload_length = get_nibble(data, data_length, 1);
  62     uint8_t payload[payload_length];
  63     if(payload_length > 0 && data_length > 0) {
  64         memcpy(payload, &data[1], payload_length);
  65     }
  66
  67     // TODO this is set up to handle rx a response with a payload, but not to
  68     // handle flow control responses for multi frame messages that we're in the
  69     // process of sending
  70
  71     switch(pci) {
  72         case PCI_SINGLE: {
  73             IsoTpMessage message = {
  74                 arbitration_id: arbitration_id,
  75                 payload: payload,
  76                 size: payload_length
  77             };
  78
  79             message_completed = isotp_handle_single_frame(handle, &message);
  80             break;
  81          }
  82         default:
  83             shims->log("Only single frame messages are supported");
  84             break;
  85     }
  86     return message_completed;
  87 }