text: /* Copyright (c) 2001 Matej Pfajfar.
   * Copyright (c) 2001-2004, Roger Dingledine.
   * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   * Copyright (c) 2007-2019, The Tor Project, Inc. */
  /* See LICENSE for licensing information */
  
  /**
   * @file relay_periodic.c
   * @brief Periodic functions for the relay subsytem
   **/
  
  #include "orconfig.h"
  #include "core/or/or.h"
  
  #include "core/mainloop/periodic.h"
  #include "core/mainloop/cpuworker.h" // XXXX use a pubsub event.
  #include "core/mainloop/mainloop.h"
  #include "core/mainloop/netstatus.h"
  #include "core/or/circuituse.h" // XXXX move have_performed_bandwidth_test
  
  #include "feature/relay/dns.h"
  #include "feature/relay/relay_periodic.h"
  #include "feature/relay/router.h"
  #include "feature/relay/routerkeys.h"
  #include "feature/relay/routermode.h"
  #include "feature/relay/selftest.h"
  #include "feature/stats/predict_ports.h"
  
  #include "lib/crypt_ops/crypto_rand.h"
  
  #include "feature/nodelist/routerinfo_st.h"
  #include "feature/control/control_events.h"
  
  #ifndef COCCI
  #define DECLARE_EVENT(name, roles, flags)         \
    static periodic_event_item_t name ## _event =   \
      PERIODIC_EVENT(name,                          \
                     PERIODIC_EVENT_ROLE_##roles,   \
                     flags)
  #endif /* !defined(COCCI) */
  
  #define FL(name) (PERIODIC_EVENT_FLAG_##name)
  
  /**
   * Periodic callback: If we're a server and initializing dns failed, retry.
   */
  static int
  retry_dns_callback(time_t now, const or_options_t *options)
  {
    (void)now;
  #define RETRY_DNS_INTERVAL (10*60)
    if (server_mode(options) && has_dns_init_failed())
      dns_init();
    return RETRY_DNS_INTERVAL;
  }
  
  DECLARE_EVENT(retry_dns, ROUTER, 0);
  
  static int dns_honesty_first_time = 1;
  
  /**
   * Periodic event: if we're an exit, see if our DNS server is telling us
   * obvious lies.
   */
  static int
  check_dns_honesty_callback(time_t now, const or_options_t *options)
  {
    (void)now;
    /* 9. and if we're an exit node, check whether our DNS is telling stories
     * to us. */
    if (net_is_disabled() ||
        ! public_server_mode(options) ||
        router_my_exit_policy_is_reject_star())
      return PERIODIC_EVENT_NO_UPDATE;
  
    if (dns_honesty_first_time) {
      /* Don't launch right when we start */
      dns_honesty_first_time = 0;
      return crypto_rand_int_range(60, 180);
    }
  
    dns_launch_correctness_checks();
    return 12*3600 + crypto_rand_int(12*3600);
  }
  
  DECLARE_EVENT(check_dns_honesty, RELAY, FL(NEED_NET));
  
  /* Periodic callback: rotate the onion keys after the period defined by the
   * "onion-key-rotation-days" consensus parameter, shut down and restart all
   * cpuworkers, and update our descriptor if necessary.
   */
  static int
  rotate_onion_key_callback(time_t now, const or_options_t *options)
  {
    if (server_mode(options)) {
      int onion_key_lifetime = get_onion_key_lifetime();
      time_t rotation_time = get_onion_key_set_at()+onion_key_lifetime;
      if (rotation_time > now) {
        return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
      }
  
      log_info(LD_GENERAL,"Rotating onion key.");
      rotate_onion_key();
      cpuworkers_rotate_keyinfo();
      if (router_rebuild_descriptor(1)<0) {
        log_info(LD_CONFIG, "Couldn't rebuild router descriptor");
      }
      if (advertised_server_mode() && !net_is_disabled())
        router_upload_dir_desc_to_dirservers(0);
      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
    }
    return PERIODIC_EVENT_NO_UPDATE;
  }
  
  DECLARE_EVENT(rotate_onion_key, ROUTER, 0);
  
  /** Periodic callback: consider rebuilding or and re-uploading our descriptor
   * (if we've passed our internal checks). */
  static int
  check_descriptor_callback(time_t now, const or_options_t *options)
  {
  /** How often do we check whether part of our router info has changed in a
   * way that would require an upload? That includes checking whether our IP
   * address has changed. */
  #define CHECK_DESCRIPTOR_INTERVAL (60)
  
    (void)options;
  
    /* 2b. Once per minute, regenerate and upload the descriptor if the old
     * one is inaccurate. */
    if (!net_is_disabled()) {
      check_descriptor_bandwidth_changed(now);
      check_descriptor_ipaddress_changed(now);
      mark_my_descriptor_dirty_if_too_old(now);
      consider_publishable_server(0);
    }
  
    return CHECK_DESCRIPTOR_INTERVAL;
  }
  
  DECLARE_EVENT(check_descriptor, ROUTER, FL(NEED_NET));
  
  static int dirport_reachability_count = 0;
  
  /**
   * Periodic callback: check whether we're reachable (as a relay), and
   * whether our bandwidth has changed enough that we need to
   * publish a new descriptor.
   */
  static int
  check_for_reachability_bw_callback(time_t now, const or_options_t *options)
  {
    /* XXXX This whole thing was stuck in the middle of what is now
     * XXXX check_descriptor_callback.  I'm not sure it's right. */
  
    /* also, check religiously for reachability, if it's within the first
     * 20 minutes of our uptime. */
    if (server_mode(options) &&
        (have_completed_a_circuit() || !any_predicted_circuits(now)) &&
        !net_is_disabled()) {
      if (get_uptime() < TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT) {
        router_do_reachability_checks(1, dirport_reachability_count==0);
        if (++dirport_reachability_count > 5)
          dirport_reachability_count = 0;
        return 1;
      } else {
        /* If we haven't checked for 12 hours and our bandwidth estimate is
         * low, do another bandwidth test. This is especially important for
         * bridges, since they might go long periods without much use. */
        const routerinfo_t *me = router_get_my_routerinfo();
        static int first_time = 1;
        if (!first_time && me &&
            me->bandwidthcapacity < me->bandwidthrate &&
            me->bandwidthcapacity < 51200) {
          reset_bandwidth_test();
        }
        first_time = 0;
  #define BANDWIDTH_RECHECK_INTERVAL (12*60*60)
        return BANDWIDTH_RECHECK_INTERVAL;
      }
    }
    return CHECK_DESCRIPTOR_INTERVAL;
  }
  
  DECLARE_EVENT(check_for_reachability_bw, ROUTER, FL(NEED_NET));
  
  /**
   * Callback: Send warnings if Tor doesn't find its ports reachable.
   */
  static int
  reachability_warnings_callback(time_t now, const or_options_t *options)
  {
    (void) now;
  
    if (get_uptime() < TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT) {
      return (int)(TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT - get_uptime());
    }
  
    if (server_mode(options) &&
        !net_is_disabled() &&
        have_completed_a_circuit()) {
      /* every 20 minutes, check and complain if necessary */
      const routerinfo_t *me = router_get_my_routerinfo();
      if (me && !check_whether_orport_reachable(options)) {
        char *address = tor_dup_ip(me->addr);
        log_warn(LD_CONFIG,"Your server (%s:%d) has not managed to confirm that "
                 "its ORPort is reachable. Relays do not publish descriptors "
                 "until their ORPort and DirPort are reachable. Please check "
                 "your firewalls, ports, address, /etc/hosts file, etc.",
                 address, me->or_port);
        control_event_server_status(LOG_WARN,
                                    "REACHABILITY_FAILED ORADDRESS=%s:%d",
                                    address, me->or_port);
        tor_free(address);
      }
  
      if (me && !check_whether_dirport_reachable(options)) {
        char *address = tor_dup_ip(me->addr);
        log_warn(LD_CONFIG,
                 "Your server (%s:%d) has not managed to confirm that its "
                 "DirPort is reachable. Relays do not publish descriptors "
                 "until their ORPort and DirPort are reachable. Please check "
                 "your firewalls, ports, address, /etc/hosts file, etc.",
                 address, me->dir_port);
        control_event_server_status(LOG_WARN,
                                    "REACHABILITY_FAILED DIRADDRESS=%s:%d",
                                    address, me->dir_port);
        tor_free(address);
      }
    }
  
    return TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT;
  }
  
  DECLARE_EVENT(reachability_warnings, ROUTER, FL(NEED_NET));
  
  /* Periodic callback: Every 30 seconds, check whether it's time to make new
   * Ed25519 subkeys.
   */
  static int
  check_ed_keys_callback(time_t now, const or_options_t *options)
  {
    if (server_mode(options)) {
      if (should_make_new_ed_keys(options, now)) {
        int new_signing_key = load_ed_keys(options, now);
        if (new_signing_key < 0 ||
            generate_ed_link_cert(options, now, new_signing_key > 0)) {
          log_err(LD_OR, "Unable to update Ed25519 keys!  Exiting.");
          tor_shutdown_event_loop_and_exit(1);
        }
      }
      return 30;
    }
    return PERIODIC_EVENT_NO_UPDATE;
  }
  
  DECLARE_EVENT(check_ed_keys, ROUTER, 0);
  
  /* Period callback: Check if our old onion keys are still valid after the
   * period of time defined by the consensus parameter
   * "onion-key-grace-period-days", otherwise expire them by setting them to
   * NULL.
   */
  static int
  check_onion_keys_expiry_time_callback(time_t now, const or_options_t *options)
  {
    if (server_mode(options)) {
      int onion_key_grace_period = get_onion_key_grace_period();
      time_t expiry_time = get_onion_key_set_at()+onion_key_grace_period;
      if (expiry_time > now) {
        return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
      }
  
      log_info(LD_GENERAL, "Expiring old onion keys.");
      expire_old_onion_keys();
      cpuworkers_rotate_keyinfo();
      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
    }
  
    return PERIODIC_EVENT_NO_UPDATE;
  }
  
  DECLARE_EVENT(check_onion_keys_expiry_time, ROUTER, 0);
  
  void
  relay_register_periodic_events(void)
  {
    periodic_events_register(&retry_dns_event);
    periodic_events_register(&check_dns_honesty_event);
    periodic_events_register(&rotate_onion_key_event);
    periodic_events_register(&check_descriptor_event);
    periodic_events_register(&check_for_reachability_bw_event);
    periodic_events_register(&reachability_warnings_event);
    periodic_events_register(&check_ed_keys_event);
    periodic_events_register(&check_onion_keys_expiry_time_event);
  
    dns_honesty_first_time = 1;
    dirport_reachability_count = 0;
  }
  
  /**
   * Update our schedule so that we'll check whether we need to update our
   * descriptor immediately, rather than after up to CHECK_DESCRIPTOR_INTERVAL
   * seconds.
   */
  void
  reschedule_descriptor_update_check(void)
  {
    periodic_event_reschedule(&check_descriptor_event);
  }
  