low-can-binding/binding/low-can-cb.cpp

   1 /*
   2  * Copyright (C) 2015, 2018 "IoT.bzh"
   3  * Author "Romain Forlot" <romain.forlot@iot.bzh>
   4  * Author "Loic Collignon" <loic.collignon@iot.bzh>
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *       http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18
  19 #include "low-can-hat.hpp"
  20 #include "low-can-apidef.h"
  21
  22 #include <map>
  23 #include <queue>
  24 #include <mutex>
  25 #include <vector>
  26 #include <thread>
  27 #include <wrap-json.h>
  28 #include <systemd/sd-event.h>
  29
  30 #include "openxc.pb.h"
  31 #include "application.hpp"
  32 #include "../can/can-encoder.hpp"
  33 #include "../can/can-bus.hpp"
  34 #include "../can/signals.hpp"
  35 #include "../can/message/message.hpp"
  36 #include "../utils/signals.hpp"
  37 #include "../diagnostic/diagnostic-message.hpp"
  38 #include "../utils/openxc-utils.hpp"
  39
  40 ///******************************************************************************
  41 ///
  42 ///             SystemD event loop Callbacks
  43 ///
  44 ///*******************************************************************************/
  45
  46 void on_no_clients(std::shared_ptr<low_can_subscription_t> can_subscription, uint32_t pid, std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
  47 {
  48         bool is_permanent_recurring_request = false;
  49
  50         if( ! can_subscription->get_diagnostic_message().empty() && can_subscription->get_diagnostic_message(pid) != nullptr)
  51         {
  52                 DiagnosticRequest diag_req = can_subscription->get_diagnostic_message(pid)->build_diagnostic_request();
  53                 active_diagnostic_request_t* adr = application_t::instance().get_diagnostic_manager().find_recurring_request(diag_req);
  54                 if( adr != nullptr)
  55                 {
  56                         is_permanent_recurring_request = adr->get_permanent();
  57
  58                         if(! is_permanent_recurring_request)
  59                                 application_t::instance().get_diagnostic_manager().cleanup_request(adr, true);
  60                 }
  61         }
  62
  63         if(! is_permanent_recurring_request)
  64                 on_no_clients(can_subscription, s);
  65 }
  66
  67 void on_no_clients(std::shared_ptr<low_can_subscription_t> can_subscription, std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
  68 {
  69         auto it = s.find(can_subscription->get_index());
  70         s.erase(it);
  71 }
  72
  73 static void push_n_notify(std::shared_ptr<message_t> m)
  74 {
  75         can_bus_t& cbm = application_t::instance().get_can_bus_manager();
  76         {
  77                 std::lock_guard<std::mutex> can_message_lock(cbm.get_can_message_mutex());
  78                 cbm.push_new_can_message(m);
  79         }
  80         cbm.get_new_can_message_cv().notify_one();
  81 }
  82
  83 int read_message(sd_event_source *event_source, int fd, uint32_t revents, void *userdata)
  84 {
  85         low_can_subscription_t* can_subscription = (low_can_subscription_t*)userdata;
  86
  87
  88         if ((revents & EPOLLIN) != 0)
  89         {
  90                 std::shared_ptr<utils::socketcan_t> s = can_subscription->get_socket();
  91                 std::shared_ptr<message_t> message = s->read_message();
  92
  93                 // Sure we got a valid CAN message ?
  94                 if (! message->get_id() == 0 && ! message->get_length() == 0)
  95                 {
  96                         push_n_notify(message);
  97                 }
  98         }
  99
 100         // check if error or hangup
 101         if ((revents & (EPOLLERR|EPOLLRDHUP|EPOLLHUP)) != 0)
 102         {
 103                 sd_event_source_unref(event_source);
 104                 can_subscription->get_socket()->close();
 105         }
 106
 107         return 0;
 108 }
 109
 110 ///******************************************************************************
 111 ///
 112 ///             Subscription and unsubscription
 113 ///
 114 ///*******************************************************************************/
 115
 116 /// @brief This will determine if an event handle needs to be created and checks if
 117 /// we got a valid afb_event to get subscribe or unsubscribe. After that launch the subscription or unsubscription
 118 /// against the application framework using that event handle.
 119 static int subscribe_unsubscribe_signal(afb_req_t request,
 120                                         bool subscribe,
 121                                         std::shared_ptr<low_can_subscription_t>& can_subscription,
 122                                         std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
 123 {
 124         int ret = 0;
 125         int sub_index = can_subscription->get_index();
 126         bool subscription_exists = s.count(sub_index);
 127
 128         // Susbcription part
 129         if(subscribe)
 130         {
 131                 /* There is no valid request to subscribe so this must be an
 132                  * internal permanent diagnostic request. Skip the subscription
 133                  * part and don't register it into the current "low-can"
 134                  * subsciptions.
 135                  */
 136                 if(! request)
 137                 {
 138                         return 0;
 139                 }
 140
 141                 // Event doesn't exist , so let's create it
 142                 if (! subscription_exists &&
 143                     (ret = can_subscription->subscribe(request)) < 0)
 144                         return ret;
 145
 146                 if(! subscription_exists)
 147                                 s[sub_index] = can_subscription;
 148
 149                 return ret;
 150         }
 151
 152         // Unsubscrition part
 153         if(! subscription_exists)
 154         {
 155                 AFB_NOTICE("There isn't any valid subscriptions for that request.");
 156                 return ret;
 157         }
 158         else if (subscription_exists &&
 159                  ! afb_event_is_valid(s[sub_index]->get_event()) )
 160         {
 161                 AFB_NOTICE("Event isn't valid, no need to unsubscribed.");
 162                 return ret;
 163         }
 164
 165         if( (ret = s[sub_index]->unsubscribe(request)) < 0)
 166                 return ret;
 167         s.erase(sub_index);
 168
 169         return ret;
 170 }
 171
 172 static int add_to_event_loop(std::shared_ptr<low_can_subscription_t>& can_subscription)
 173 {
 174                 struct sd_event_source* event_source = nullptr;
 175                 return ( sd_event_add_io(afb_daemon_get_event_loop(),
 176                         &event_source,
 177                         can_subscription->get_socket()->socket(),
 178                         EPOLLIN,
 179                         read_message,
 180                         can_subscription.get()));
 181 }
 182
 183 static int subscribe_unsubscribe_diagnostic_messages(afb_req_t request,
 184                                                      bool subscribe,
 185                                                      std::vector<std::shared_ptr<diagnostic_message_t> > diagnostic_messages,
 186                                                      struct event_filter_t& event_filter,
 187                                                      std::map<int, std::shared_ptr<low_can_subscription_t> >& s,
 188                                                      bool perm_rec_diag_req)
 189 {
 190         int rets = 0;
 191         application_t& app = application_t::instance();
 192         diagnostic_manager_t& diag_m = app.get_diagnostic_manager();
 193
 194         for(const auto& sig : diagnostic_messages)
 195         {
 196                 DiagnosticRequest* diag_req = new DiagnosticRequest(sig->build_diagnostic_request());
 197                 event_filter.frequency = event_filter.frequency == 0 ? sig->get_frequency() : event_filter.frequency;
 198                 std::shared_ptr<low_can_subscription_t> can_subscription;
 199
 200                 auto it =  std::find_if(s.begin(), s.end(), [&sig](std::pair<int, std::shared_ptr<low_can_subscription_t> > sub){ return (! sub.second->get_diagnostic_message().empty());});
 201                 can_subscription = it != s.end() ?
 202                         it->second :
 203                         std::make_shared<low_can_subscription_t>(low_can_subscription_t(event_filter));
 204                 // If the requested diagnostic message is not supported by the car then unsubcribe it
 205                 // no matter what we want, worst case will be a failed unsubscription but at least we won't
 206                 // poll a PID for nothing.
 207                 if(sig->get_supported() && subscribe)
 208                 {
 209                         if (!app.isEngineOn())
 210                                 AFB_WARNING("signal: Engine is off, %s won't received responses until it's on",  sig->get_name().c_str());
 211
 212                         diag_m.add_recurring_request(diag_req, sig->get_name().c_str(), false, sig->get_decoder(), sig->get_callback(), event_filter.frequency, perm_rec_diag_req);
 213                         if(can_subscription->create_rx_filter(sig) < 0)
 214                                 {return -1;}
 215                         AFB_DEBUG("Signal: %s subscribed", sig->get_name().c_str());
 216                         if(it == s.end() && add_to_event_loop(can_subscription) < 0)
 217                         {
 218                                 diag_m.cleanup_request(
 219                                         diag_m.find_recurring_request(*diag_req), true);
 220                                 AFB_WARNING("signal: %s isn't supported. Canceling operation.",  sig->get_name().c_str());
 221                                 return -1;
 222                         }
 223                 }
 224                 else
 225                 {
 226                         if(sig->get_supported())
 227                         {AFB_DEBUG("%s cancelled due to unsubscribe", sig->get_name().c_str());}
 228                         else
 229                         {
 230                                 AFB_WARNING("signal: %s isn't supported. Canceling operation.", sig->get_name().c_str());
 231                                 return -1;
 232                         }
 233                 }
 234                 int ret = subscribe_unsubscribe_signal(request, subscribe, can_subscription, s);
 235                 if(ret < 0)
 236                         return ret;
 237
 238                 rets++;
 239         }
 240
 241         return rets;
 242 }
 243
 244 static int subscribe_unsubscribe_signals(afb_req_t request,
 245                                              bool subscribe,
 246                                              std::vector<std::shared_ptr<signal_t> > signals,
 247                                              struct event_filter_t& event_filter,
 248                                              std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
 249 {
 250         int rets = 0;
 251         for(const auto& sig: signals)
 252         {
 253                 auto it =  std::find_if(s.begin(), s.end(), [&sig, &event_filter](std::pair<int, std::shared_ptr<low_can_subscription_t> > sub){ return sub.second->is_signal_subscription_corresponding(sig, event_filter) ; });
 254                 std::shared_ptr<low_can_subscription_t> can_subscription;
 255                 if(it != s.end())
 256                         {can_subscription = it->second;}
 257                 else
 258                 {
 259                          can_subscription = std::make_shared<low_can_subscription_t>(low_can_subscription_t(event_filter));
 260                         if(can_subscription->create_rx_filter(sig) < 0)
 261                                 {return -1;}
 262                         if(add_to_event_loop(can_subscription) < 0)
 263                                 {return -1;}
 264                 }
 265
 266                 if(subscribe_unsubscribe_signal(request, subscribe, can_subscription, s) < 0)
 267                         {return -1;}
 268
 269                 rets++;
 270                 AFB_DEBUG("%s Signal: %s %ssubscribed", sig->get_message()->is_fd() ? "FD": "", sig->get_name().c_str(), subscribe ? "":"un");
 271         }
 272         return rets;
 273 }
 274
 275 ///
 276 /// @brief subscribe to all signals in the vector signals
 277 ///
 278 /// @param[in] afb_req request : contains original request use to subscribe or unsubscribe
 279 /// @param[in] subscribe boolean value, which chooses between a subscription operation or an unsubscription
 280 /// @param[in] signals -  struct containing vectors with signal_t and diagnostic_messages to subscribe
 281 ///
 282 /// @return Number of correctly subscribed signal
 283 ///
 284 static int subscribe_unsubscribe_signals(afb_req_t request,
 285                                          bool subscribe,
 286                                          const struct utils::signals_found& signals,
 287                                          struct event_filter_t& event_filter)
 288 {
 289         int rets = 0;
 290         utils::signals_manager_t& sm = utils::signals_manager_t::instance();
 291
 292         std::lock_guard<std::mutex> subscribed_signals_lock(sm.get_subscribed_signals_mutex());
 293         std::map<int, std::shared_ptr<low_can_subscription_t> >& s = sm.get_subscribed_signals();
 294
 295         rets += subscribe_unsubscribe_diagnostic_messages(request, subscribe, signals.diagnostic_messages, event_filter, s, false);
 296         rets += subscribe_unsubscribe_signals(request, subscribe, signals.signals, event_filter, s);
 297
 298         return rets;
 299 }
 300
 301 static int one_subscribe_unsubscribe(afb_req_t request,
 302                                      bool subscribe,
 303                                      const std::string& tag,
 304                                      json_object* args)
 305 {
 306         int ret = 0;
 307         struct event_filter_t event_filter;
 308         struct json_object  *filter, *obj;
 309         struct utils::signals_found sf;
 310
 311         // computes the filter
 312         if (json_object_object_get_ex(args, "filter", &filter))
 313         {
 314                 if (json_object_object_get_ex(filter, "frequency", &obj)
 315                 && (json_object_is_type(obj, json_type_double) || json_object_is_type(obj, json_type_int)))
 316                         {event_filter.frequency = (float)json_object_get_double(obj);}
 317                 if (json_object_object_get_ex(filter, "min", &obj)
 318                 && (json_object_is_type(obj, json_type_double) || json_object_is_type(obj, json_type_int)))
 319                         {event_filter.min = (float)json_object_get_double(obj);}
 320                 if (json_object_object_get_ex(filter, "max", &obj)
 321                 && (json_object_is_type(obj, json_type_double) || json_object_is_type(obj, json_type_int)))
 322                         {event_filter.max = (float)json_object_get_double(obj);}
 323         }
 324
 325         // subscribe or unsubscribe
 326         openxc_DynamicField search_key = build_DynamicField(tag);
 327         sf = utils::signals_manager_t::instance().find_signals(search_key);
 328         if (sf.signals.empty() && sf.diagnostic_messages.empty())
 329         {
 330                 AFB_NOTICE("No signal(s) found for %s.", tag.c_str());
 331                 ret = -1;
 332         }
 333         else
 334                 {ret = subscribe_unsubscribe_signals(request, subscribe, sf, event_filter);}
 335
 336         return ret;
 337 }
 338 static int process_one_subscribe_args(afb_req_t request, bool subscribe, json_object *args)
 339 {
 340         int rc = 0, rc2=0;
 341         json_object *x = nullptr, *event = nullptr;
 342         if(args == NULL ||
 343                 !json_object_object_get_ex(args, "event", &event))
 344         {
 345                 rc = one_subscribe_unsubscribe(request, subscribe, "*", args);
 346         }
 347         else if (json_object_get_type(event) != json_type_array)
 348         {
 349                 rc = one_subscribe_unsubscribe(request, subscribe, json_object_get_string(event), args);
 350         }
 351         else
 352         {
 353                 for (int i = 0 ; i < json_object_array_length(event); i++)
 354                 {
 355                         x = json_object_array_get_idx(event, i);
 356                         rc2 = one_subscribe_unsubscribe(request, subscribe, json_object_get_string(x), args);
 357                         if (rc >= 0)
 358                                 rc = rc2 >= 0 ? rc + rc2 : rc2;
 359                 }
 360         }
 361         return rc;
 362 }
 363
 364 static void do_subscribe_unsubscribe(afb_req_t request, bool subscribe)
 365 {
 366         int rc = 0;
 367         struct json_object *args, *x;
 368
 369         args = afb_req_json(request);
 370         if (json_object_get_type(args) == json_type_array)
 371         {
 372                 for(int i = 0; i < json_object_array_length(args); i++)
 373                 {
 374                         x = json_object_array_get_idx(args, i);
 375                         rc += process_one_subscribe_args(request, subscribe, x);
 376                 }
 377         }
 378         else
 379         {
 380                 rc += process_one_subscribe_args(request, subscribe, args);
 381         }
 382
 383         if (rc >= 0)
 384                 afb_req_success(request, NULL, NULL);
 385         else
 386                 afb_req_fail(request, "error", NULL);
 387 }
 388
 389 void auth(afb_req_t request)
 390 {
 391         afb_req_session_set_LOA(request, 1);
 392         afb_req_success(request, NULL, NULL);
 393 }
 394
 395 void subscribe(afb_req_t request)
 396 {
 397         do_subscribe_unsubscribe(request, true);
 398 }
 399
 400 void unsubscribe(afb_req_t request)
 401 {
 402         do_subscribe_unsubscribe(request, false);
 403 }
 404
 405 static int send_frame(struct canfd_frame& cfd, const std::string& bus_name)
 406 {
 407         if(bus_name.empty()) {
 408                 return -1;
 409         }
 410
 411         std::map<std::string, std::shared_ptr<low_can_subscription_t> >& cd = application_t::instance().get_can_devices();
 412
 413         if( cd.count(bus_name) == 0)
 414                 {cd[bus_name] = std::make_shared<low_can_subscription_t>(low_can_subscription_t());}
 415
 416         return cd[bus_name]->tx_send(*cd[bus_name], cfd, bus_name);
 417 }
 418
 419 static void write_raw_frame(afb_req_t request, const std::string& bus_name, json_object *json_value)
 420 {
 421         struct canfd_frame cfd;
 422         struct json_object *can_data = nullptr;
 423
 424         ::memset(&cfd, 0, sizeof(cfd));
 425
 426         if(wrap_json_unpack(json_value, "{si, si, so !}",
 427                               "can_id", &cfd.can_id,
 428                               "can_dlc", &cfd.len,
 429                               "can_data", &can_data))
 430         {
 431                 afb_req_fail(request, "Invalid", "Frame object malformed");
 432                 return;
 433         }
 434
 435         if(cfd.len <= 8 && cfd.len > 0)
 436         {
 437                 for (int i = 0 ; i < cfd.len ; i++)
 438                 {
 439                         struct json_object *one_can_data = json_object_array_get_idx(can_data, i);
 440                         cfd.data[i] = (json_object_is_type(one_can_data, json_type_int)) ?
 441                                         (uint8_t)json_object_get_int(one_can_data) : 0;
 442                 }
 443         }
 444         else
 445         {
 446                 afb_req_fail(request, "Invalid", "Data array must hold 1 to 8 values.");
 447                 return;
 448         }
 449
 450         if(! send_frame(cfd, application_t::instance().get_can_bus_manager().get_can_device_name(bus_name)))
 451                 afb_req_success(request, nullptr, "Message correctly sent");
 452         else
 453                 afb_req_fail(request, "Error", "sending the message. See the log for more details.");
 454 }
 455
 456 static void write_signal(afb_req_t request, const std::string& name, json_object *json_value)
 457 {
 458         struct canfd_frame cfd;
 459         struct utils::signals_found sf;
 460         signal_encoder encoder = nullptr;
 461         bool send = true;
 462
 463         ::memset(&cfd, 0, sizeof(cfd));
 464
 465         openxc_DynamicField search_key = build_DynamicField(name);
 466         sf = utils::signals_manager_t::instance().find_signals(search_key);
 467         openxc_DynamicField dynafield_value = build_DynamicField(json_value);
 468
 469         if (sf.signals.empty())
 470         {
 471                 afb_req_fail_f(request, "No signal(s) found for %s. Message not sent.", name.c_str());
 472                 return;
 473         }
 474
 475         std::shared_ptr<signal_t>& sig = sf.signals[0];
 476         if(! sig->get_writable())
 477         {
 478                 afb_req_fail_f(request, "%s isn't writable. Message not sent.", sig->get_name().c_str());
 479                 return;
 480         }
 481
 482         uint64_t value = (encoder = sig->get_encoder()) ?
 483                         encoder(*sig, dynafield_value, &send) :
 484                         encoder_t::encode_DynamicField(*sig, dynafield_value, &send);
 485
 486         cfd = encoder_t::build_frame(sig, value);
 487         if(! send_frame(cfd, sig->get_message()->get_bus_device_name()) && send)
 488                 afb_req_success(request, nullptr, "Message correctly sent");
 489         else
 490                 afb_req_fail(request, "Error", "Sending the message. See the log for more details.");
 491 }
 492
 493 void write(afb_req_t request)
 494 {
 495         struct json_object* args = nullptr, *json_value = nullptr;
 496         const char *name = nullptr;
 497
 498         args = afb_req_json(request);
 499
 500         // Process about Raw CAN message on CAN bus directly
 501         if (args != NULL && ! wrap_json_unpack(args, "{ss, so !}",
 502                                                "bus_name", &name,
 503                                                "frame", &json_value))
 504                 write_raw_frame(request, name, json_value);
 505
 506         // Search signal then encode value.
 507         else if(args != NULL &&
 508                 ! wrap_json_unpack(args, "{ss, so !}",
 509                                    "signal_name", &name,
 510                                    "signal_value", &json_value))
 511                 write_signal(request, std::string(name), json_value);
 512         else
 513                 afb_req_fail(request, "Error", "Request argument malformed");
 514 }
 515
 516 static struct json_object *get_signals_value(const std::string& name)
 517 {
 518         struct utils::signals_found sf;
 519         struct json_object *ans = nullptr;
 520
 521         openxc_DynamicField search_key = build_DynamicField(name);
 522         sf = utils::signals_manager_t::instance().find_signals(search_key);
 523
 524         if (sf.signals.empty())
 525         {
 526                 AFB_WARNING("No signal(s) found for %s.", name.c_str());
 527                 return NULL;
 528         }
 529         ans = json_object_new_array();
 530         for(const auto& sig: sf.signals)
 531         {
 532                 struct json_object *jobj = json_object_new_object();
 533                 json_object_object_add(jobj, "event", json_object_new_string(sig->get_name().c_str()));
 534                 json_object_object_add(jobj, "value", json_object_new_double(sig->get_last_value()));
 535                 json_object_array_add(ans, jobj);
 536         }
 537
 538         return ans;
 539 }
 540 void get(afb_req_t request)
 541 {
 542         int rc = 0;
 543         struct json_object* args = nullptr,
 544                 *json_name = nullptr;
 545         json_object *ans = nullptr;
 546
 547         args = afb_req_json(request);
 548
 549         // Process about Raw CAN message on CAN bus directly
 550         if (args != nullptr &&
 551                 (json_object_object_get_ex(args, "event", &json_name) && json_object_is_type(json_name, json_type_string) ))
 552         {
 553                 ans = get_signals_value(json_object_get_string(json_name));
 554                 if (!ans)
 555                         rc = -1;
 556         }
 557         else
 558         {
 559                 AFB_ERROR("Request argument malformed. Please use the following syntax:");
 560                 rc = -1;
 561         }
 562
 563         if (rc >= 0)
 564                 afb_req_success(request, ans, NULL);
 565         else
 566                 afb_req_fail(request, "error", NULL);
 567 }
 568
 569
 570 static struct json_object *list_can_message(const std::string& name)
 571 {
 572         struct utils::signals_found sf;
 573         struct json_object *ans = nullptr;
 574
 575         openxc_DynamicField search_key = build_DynamicField(name);
 576         sf = utils::signals_manager_t::instance().find_signals(search_key);
 577
 578         if (sf.signals.empty() && sf.diagnostic_messages.empty())
 579         {
 580                 AFB_WARNING("No signal(s) found for %s.", name.c_str());
 581                 return NULL;
 582         }
 583         ans = json_object_new_array();
 584         for(const auto& sig: sf.signals)
 585         {
 586                 json_object_array_add(ans,
 587                         json_object_new_string(sig->get_name().c_str()));
 588         }
 589         for(const auto& sig: sf.diagnostic_messages)
 590         {
 591                 json_object_array_add(ans,
 592                         json_object_new_string(sig->get_name().c_str()));
 593         }
 594
 595         return ans;
 596 }
 597
 598 void list(afb_req_t request)
 599 {
 600         int rc = 0;
 601         json_object *ans = nullptr;
 602         struct json_object* args = nullptr,
 603                 *json_name = nullptr;
 604         args = afb_req_json(request);
 605         const char *name;
 606         if ((args != nullptr) &&
 607                 (json_object_object_get_ex(args, "event", &json_name) && json_object_is_type(json_name, json_type_string)))
 608         {
 609                 name = json_object_get_string(json_name);
 610         }
 611         else
 612         {
 613                 name = "*";
 614         }
 615
 616         ans = list_can_message(name);
 617         if (!ans)
 618                 rc = -1;
 619
 620         if (rc >= 0)
 621                 afb_req_success(request, ans, NULL);
 622         else
 623                 afb_req_fail(request, "error", NULL);
 624 }
 625
 626 /// @brief Initialize the binding.
 627 ///
 628 /// @param[in] service Structure which represent the Application Framework Binder.
 629 ///
 630 /// @return Exit code, zero if success.
 631 int init_binding(afb_api_t api)
 632 {
 633         uint32_t ret = 1;
 634         can_bus_t& can_bus_manager = application_t::instance().get_can_bus_manager();
 635
 636         can_bus_manager.set_can_devices();
 637         can_bus_manager.start_threads();
 638
 639         /// Initialize Diagnostic manager that will handle obd2 requests.
 640         /// We pass by default the first CAN bus device to its Initialization.
 641         /// TODO: be able to choose the CAN bus device that will be use as Diagnostic bus.
 642         if(application_t::instance().get_diagnostic_manager().initialize())
 643                 ret = 0;
 644
 645         // Add a recurring dignostic message request to get engine speed at all times.
 646         openxc_DynamicField search_key = build_DynamicField("diagnostic_messages.engine.speed");
 647         struct utils::signals_found sf = utils::signals_manager_t::instance().find_signals(search_key);
 648
 649         if(sf.signals.empty() && sf.diagnostic_messages.size() == 1)
 650         {
 651                 afb_req_t request = nullptr;
 652
 653                 struct event_filter_t event_filter;
 654                 event_filter.frequency = sf.diagnostic_messages.front()->get_frequency();
 655
 656                 utils::signals_manager_t& sm = utils::signals_manager_t::instance();
 657                 std::map<int, std::shared_ptr<low_can_subscription_t> >& s = sm.get_subscribed_signals();
 658
 659                 subscribe_unsubscribe_diagnostic_messages(request, true, sf.diagnostic_messages, event_filter, s, true);
 660         }
 661
 662         if(ret)
 663                 AFB_ERROR("There was something wrong with CAN device Initialization.");
 664
 665         return ret;
 666 }