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