text: /* Copyright (c) 2016-2020, The Tor Project, Inc. */
  /* See LICENSE for licensing information */
  
  /**
   * \file hs_client.c
   * \brief Implement next generation hidden service client functionality
   **/
  
  #define HS_CLIENT_PRIVATE
  
  #include "core/or/or.h"
  #include "app/config/config.h"
  #include "core/crypto/hs_ntor.h"
  #include "core/mainloop/connection.h"
  #include "core/or/circuitbuild.h"
  #include "core/or/circuitlist.h"
  #include "core/or/circuituse.h"
  #include "core/or/connection_edge.h"
  #include "core/or/extendinfo.h"
  #include "core/or/reasons.h"
  #include "feature/client/circpathbias.h"
  #include "feature/dirclient/dirclient.h"
  #include "feature/dircommon/directory.h"
  #include "feature/hs/hs_cache.h"
  #include "feature/hs/hs_cell.h"
  #include "feature/hs/hs_circuit.h"
  #include "feature/hs/hs_circuitmap.h"
  #include "feature/hs/hs_client.h"
  #include "feature/hs/hs_control.h"
  #include "feature/hs/hs_descriptor.h"
  #include "feature/hs/hs_ident.h"
  #include "feature/nodelist/describe.h"
  #include "feature/nodelist/networkstatus.h"
  #include "feature/nodelist/nodelist.h"
  #include "feature/nodelist/routerset.h"
  #include "feature/rend/rendclient.h"
  #include "lib/crypt_ops/crypto_format.h"
  #include "lib/crypt_ops/crypto_rand.h"
  #include "lib/crypt_ops/crypto_util.h"
  
  #include "core/or/cpath_build_state_st.h"
  #include "feature/dircommon/dir_connection_st.h"
  #include "core/or/entry_connection_st.h"
  #include "core/or/extend_info_st.h"
  #include "core/or/origin_circuit_st.h"
  #include "core/or/socks_request_st.h"
  
  /** Client-side authorizations for hidden services; map of service identity
   * public key to hs_client_service_authorization_t *. */
  static digest256map_t *client_auths = NULL;
  
  #include "trunnel/hs/cell_introduce1.h"
  
  /** Return a human-readable string for the client fetch status code. */
  static const char *
  fetch_status_to_string(hs_client_fetch_status_t status)
  {
    switch (status) {
    case HS_CLIENT_FETCH_ERROR:
      return "Internal error";
    case HS_CLIENT_FETCH_LAUNCHED:
      return "Descriptor fetch launched";
    case HS_CLIENT_FETCH_HAVE_DESC:
      return "Already have descriptor";
    case HS_CLIENT_FETCH_NO_HSDIRS:
      return "No more HSDir available to query";
    case HS_CLIENT_FETCH_NOT_ALLOWED:
      return "Fetching descriptors is not allowed";
    case HS_CLIENT_FETCH_MISSING_INFO:
      return "Missing directory information";
    case HS_CLIENT_FETCH_PENDING:
      return "Pending descriptor fetch";
    default:
      return "(Unknown client fetch status code)";
    }
  }
  
  /** Return true iff tor should close the SOCKS request(s) for the descriptor
   * fetch that ended up with this given status code. */
  static int
  fetch_status_should_close_socks(hs_client_fetch_status_t status)
  {
    switch (status) {
    case HS_CLIENT_FETCH_NO_HSDIRS:
      /* No more HSDir to query, we can't complete the SOCKS request(s). */
    case HS_CLIENT_FETCH_ERROR:
      /* The fetch triggered an internal error. */
    case HS_CLIENT_FETCH_NOT_ALLOWED:
      /* Client is not allowed to fetch (FetchHidServDescriptors 0). */
      goto close;
    case HS_CLIENT_FETCH_MISSING_INFO:
    case HS_CLIENT_FETCH_HAVE_DESC:
    case HS_CLIENT_FETCH_PENDING:
    case HS_CLIENT_FETCH_LAUNCHED:
      /* The rest doesn't require tor to close the SOCKS request(s). */
      goto no_close;
    }
  
   no_close:
    return 0;
   close:
    return 1;
  }
  
  /* Return a newly allocated list of all the entry connections that matches the
   * given service identity pk. If service_identity_pk is NULL, all entry
   * connections with an hs_ident are returned.
   *
   * Caller must free the returned list but does NOT have ownership of the
   * object inside thus they have to remain untouched. */
  static smartlist_t *
  find_entry_conns(const ed25519_public_key_t *service_identity_pk)
  {
    time_t now = time(NULL);
    smartlist_t *conns = NULL, *entry_conns = NULL;
  
    entry_conns = smartlist_new();
  
    conns = connection_list_by_type_state(CONN_TYPE_AP,
                                          AP_CONN_STATE_RENDDESC_WAIT);
    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
      entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn);
      const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
  
      /* Only consider the entry connections that matches the service for which
       * we just fetched its descriptor. */
      if (!edge_conn->hs_ident ||
          (service_identity_pk &&
           !ed25519_pubkey_eq(service_identity_pk,
                              &edge_conn->hs_ident->identity_pk))) {
        continue;
      }
      assert_connection_ok(base_conn, now);
  
      /* Validated! Add the entry connection to the list. */
      smartlist_add(entry_conns, entry_conn);
    } SMARTLIST_FOREACH_END(base_conn);
  
    /* We don't have ownership of the objects in this list. */
    smartlist_free(conns);
    return entry_conns;
  }
  
  /* Cancel all descriptor fetches currently in progress. */
  static void
  cancel_descriptor_fetches(void)
  {
    smartlist_t *conns =
      connection_list_by_type_purpose(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC);
    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
      const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident;
      if (BUG(ident == NULL)) {
        /* A directory connection fetching a service descriptor can't have an
         * empty hidden service identifier. */
        continue;
      }
      log_debug(LD_REND, "Marking for close a directory connection fetching "
                         "a hidden service descriptor for service %s.",
                safe_str_client(ed25519_fmt(&ident->identity_pk)));
      connection_mark_for_close(conn);
    } SMARTLIST_FOREACH_END(conn);
  
    /* No ownership of the objects in this list. */
    smartlist_free(conns);
    log_info(LD_REND, "Hidden service client descriptor fetches cancelled.");
  }
  
  /** Get all connections that are waiting on a circuit and flag them back to
   * waiting for a hidden service descriptor for the given service key
   * service_identity_pk. */
  static void
  flag_all_conn_wait_desc(const ed25519_public_key_t *service_identity_pk)
  {
    tor_assert(service_identity_pk);
  
    smartlist_t *conns =
      connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_CIRCUIT_WAIT);
  
    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
      edge_connection_t *edge_conn;
      if (BUG(!CONN_IS_EDGE(conn))) {
        continue;
      }
      edge_conn = TO_EDGE_CONN(conn);
      if (edge_conn->hs_ident &&
          ed25519_pubkey_eq(&edge_conn->hs_ident->identity_pk,
                            service_identity_pk)) {
        connection_ap_mark_as_waiting_for_renddesc(TO_ENTRY_CONN(conn));
      }
    } SMARTLIST_FOREACH_END(conn);
  
    smartlist_free(conns);
  }
  
  /** Remove tracked HSDir requests from our history for this hidden service
   * identity public key. */
  static void
  purge_hid_serv_request(const ed25519_public_key_t *identity_pk)
  {
    char base64_blinded_pk[ED25519_BASE64_LEN + 1];
    ed25519_public_key_t blinded_pk;
  
    tor_assert(identity_pk);
  
    /* Get blinded pubkey of hidden service. It is possible that we just moved
     * to a new time period meaning that we won't be able to purge the request
     * from the previous time period. That is fine because they will expire at
     * some point and we don't care about those anymore. */
    hs_build_blinded_pubkey(identity_pk, NULL, 0,
                            hs_get_time_period_num(0), &blinded_pk);
    ed25519_public_to_base64(base64_blinded_pk, &blinded_pk);
    /* Purge last hidden service request from cache for this blinded key. */
    hs_purge_hid_serv_from_last_hid_serv_requests(base64_blinded_pk);
  }
  
  /** Return true iff there is at least one pending directory descriptor request
   * for the service identity_pk. */
  static int
  directory_request_is_pending(const ed25519_public_key_t *identity_pk)
  {
    int ret = 0;
    smartlist_t *conns =
      connection_list_by_type_purpose(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC);
  
    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
      const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident;
      if (BUG(ident == NULL)) {
        /* A directory connection fetching a service descriptor can't have an
         * empty hidden service identifier. */
        continue;
      }
      if (!ed25519_pubkey_eq(identity_pk, &ident->identity_pk)) {
        continue;
      }
      ret = 1;
      break;
    } SMARTLIST_FOREACH_END(conn);
  
    /* No ownership of the objects in this list. */
    smartlist_free(conns);
    return ret;
  }
  
  /** Helper function that changes the state of an entry connection to waiting
   * for a circuit. For this to work properly, the connection timestamps are set
   * to now and the connection is then marked as pending for a circuit. */
  static void
  mark_conn_as_waiting_for_circuit(connection_t *conn, time_t now)
  {
    tor_assert(conn);
  
    /* Because the connection can now proceed to opening circuit and ultimately
     * connect to the service, reset those timestamp so the connection is
     * considered "fresh" and can continue without being closed too early. */
    conn->timestamp_created = now;
    conn->timestamp_last_read_allowed = now;
    conn->timestamp_last_write_allowed = now;
    /* Change connection's state into waiting for a circuit. */
    conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
  
    connection_ap_mark_as_pending_circuit(TO_ENTRY_CONN(conn));
  }
  
  /** We failed to fetch a descriptor for the service with <b>identity_pk</b>
   * because of <b>status</b>. Find all pending SOCKS connections for this
   * service that are waiting on the descriptor and close them with
   * <b>reason</b>. */
  static void
  close_all_socks_conns_waiting_for_desc(const ed25519_public_key_t *identity_pk,
                                         hs_client_fetch_status_t status,
                                         int reason)
  {
    unsigned int count = 0;
    smartlist_t *entry_conns = find_entry_conns(identity_pk);
  
    SMARTLIST_FOREACH_BEGIN(entry_conns, entry_connection_t *, entry_conn) {
      /* Unattach the entry connection which will close for the reason. */
      connection_mark_unattached_ap(entry_conn, reason);
      count++;
    } SMARTLIST_FOREACH_END(entry_conn);
  
    if (count > 0) {
      char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
      hs_build_address(identity_pk, HS_VERSION_THREE, onion_address);
      log_notice(LD_REND, "Closed %u streams for service %s.onion "
                          "for reason %s. Fetch status: %s.",
                 count, safe_str_client(onion_address),
                 stream_end_reason_to_string(reason),
                 fetch_status_to_string(status));
    }
  
    /* No ownership of the object(s) in this list. */
    smartlist_free(entry_conns);
  }
  
  /** Find all pending SOCKS connection waiting for a descriptor and retry them
   * all. This is called when the directory information changed. */
  STATIC void
  retry_all_socks_conn_waiting_for_desc(void)
  {
    smartlist_t *entry_conns = find_entry_conns(NULL);
  
    SMARTLIST_FOREACH_BEGIN(entry_conns, entry_connection_t *, entry_conn) {
      hs_client_fetch_status_t status;
      edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
      connection_t *base_conn = &edge_conn->base_;
  
      /* Ignore non HS or non v3 connection. */
      if (edge_conn->hs_ident == NULL) {
        continue;
      }
  
      /* In this loop, we will possibly try to fetch a descriptor for the
       * pending connections because we just got more directory information.
       * However, the refetch process can cleanup all SOCKS request to the same
       * service if an internal error happens. Thus, we can end up with closed
       * connections in our list. */
      if (base_conn->marked_for_close) {
        continue;
      }
  
      /* XXX: There is an optimization we could do which is that for a service
       * key, we could check if we can fetch and remember that decision. */
  
      /* Order a refetch in case it works this time. */
      status = hs_client_refetch_hsdesc(&edge_conn->hs_ident->identity_pk);
      if (status == HS_CLIENT_FETCH_HAVE_DESC) {
        /* This is a rare case where a SOCKS connection is in state waiting for
         * a descriptor but we do have it in the cache.
         *
         * This can happen is tor comes back from suspend where it previously
         * had the descriptor but the intro points were not usuable. Once it
         * came back to life, the intro point failure cache was cleaned up and
         * thus the descriptor became usable again leaving us in this code path.
         *
         * We'll mark the connection as waiting for a circuit so the descriptor
         * can be retried. This is safe because a connection in state waiting
         * for a descriptor can not be in the entry connection pending list. */
        mark_conn_as_waiting_for_circuit(base_conn, approx_time());
        continue;
      }
      /* In the case of an error, either all SOCKS connections have been
       * closed or we are still missing directory information. Leave the
       * connection in renddesc wait state so when we get more info, we'll be
       * able to try it again. */
    } SMARTLIST_FOREACH_END(entry_conn);
  
    /* We don't have ownership of those objects. */
    smartlist_free(entry_conns);
  }
  
  /** A v3 HS circuit successfully connected to the hidden service. Update the
   * stream state at <b>hs_conn_ident</b> appropriately. */
  static void
  note_connection_attempt_succeeded(const hs_ident_edge_conn_t *hs_conn_ident)
  {
    tor_assert(hs_conn_ident);
  
    /* Remove from the hid serv cache all requests for that service so we can
     * query the HSDir again later on for various reasons. */
    purge_hid_serv_request(&hs_conn_ident->identity_pk);
  
    /* The v2 subsystem cleans up the intro point time out flag at this stage.
     * We don't try to do it here because we still need to keep intact the intro
     * point state for future connections. Even though we are able to connect to
     * the service, doesn't mean we should reset the timed out intro points.
     *
     * It is not possible to have successfully connected to an intro point
     * present in our cache that was on error or timed out. Every entry in that
     * cache have a 2 minutes lifetime so ultimately the intro point(s) state
     * will be reset and thus possible to be retried. */
  }
  
  /** Given the pubkey of a hidden service in <b>onion_identity_pk</b>, fetch its
   * descriptor by launching a dir connection to <b>hsdir</b>. Return a
   * hs_client_fetch_status_t status code depending on how it went. */
  static hs_client_fetch_status_t
  directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
                                 const routerstatus_t *hsdir)
  {
    uint64_t current_time_period = hs_get_time_period_num(0);
    ed25519_public_key_t blinded_pubkey;
    char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
    hs_ident_dir_conn_t hs_conn_dir_ident;
  
    tor_assert(hsdir);
    tor_assert(onion_identity_pk);
  
    /* Get blinded pubkey */
    hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
                            current_time_period, &blinded_pubkey);
    /* ...and base64 it. */
    ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
  
    /* Copy onion pk to a dir_ident so that we attach it to the dir conn */
    hs_ident_dir_conn_init(onion_identity_pk, &blinded_pubkey,
                           &hs_conn_dir_ident);
  
    /* Setup directory request */
    directory_request_t *req =
      directory_request_new(DIR_PURPOSE_FETCH_HSDESC);
    directory_request_set_routerstatus(req, hsdir);
    directory_request_set_indirection(req, DIRIND_ANONYMOUS);
    directory_request_set_resource(req, base64_blinded_pubkey);
    directory_request_fetch_set_hs_ident(req, &hs_conn_dir_ident);
    directory_initiate_request(req);
    directory_request_free(req);
  
    log_info(LD_REND, "Descriptor fetch request for service %s with blinded "
                      "key %s to directory %s",
             safe_str_client(ed25519_fmt(onion_identity_pk)),
             safe_str_client(base64_blinded_pubkey),
             safe_str_client(routerstatus_describe(hsdir)));
  
    /* Fire a REQUESTED event on the control port. */
    hs_control_desc_event_requested(onion_identity_pk, base64_blinded_pubkey,
                                    hsdir);
  
    /* Cleanup memory. */
    memwipe(&blinded_pubkey, 0, sizeof(blinded_pubkey));
    memwipe(base64_blinded_pubkey, 0, sizeof(base64_blinded_pubkey));
    memwipe(&hs_conn_dir_ident, 0, sizeof(hs_conn_dir_ident));
  
    return HS_CLIENT_FETCH_LAUNCHED;
  }
  
  /** Return the HSDir we should use to fetch the descriptor of the hidden
   *  service with identity key <b>onion_identity_pk</b>. */
  STATIC routerstatus_t *
  pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk)
  {
    char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
    uint64_t current_time_period = hs_get_time_period_num(0);
    smartlist_t *responsible_hsdirs = NULL;
    ed25519_public_key_t blinded_pubkey;
    routerstatus_t *hsdir_rs = NULL;
  
    tor_assert(onion_identity_pk);
  
    /* Get blinded pubkey of hidden service */
    hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
                            current_time_period, &blinded_pubkey);
    /* ...and base64 it. */
    ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
  
    /* Get responsible hsdirs of service for this time period */
    responsible_hsdirs = smartlist_new();
  
    hs_get_responsible_hsdirs(&blinded_pubkey, current_time_period,
                              0, 1, responsible_hsdirs);
  
    log_debug(LD_REND, "Found %d responsible HSDirs and about to pick one.",
             smartlist_len(responsible_hsdirs));
  
    /* Pick an HSDir from the responsible ones. The ownership of
     * responsible_hsdirs is given to this function so no need to free it. */
    hsdir_rs = hs_pick_hsdir(responsible_hsdirs, base64_blinded_pubkey, NULL);
  
    return hsdir_rs;
  }
  
  /** Fetch a v3 descriptor using the given <b>onion_identity_pk</b>.
   *
   * On success, HS_CLIENT_FETCH_LAUNCHED is returned. Otherwise, an error from
   * hs_client_fetch_status_t is returned. */
  MOCK_IMPL(STATIC hs_client_fetch_status_t,
  fetch_v3_desc, (const ed25519_public_key_t *onion_identity_pk))
  {
    routerstatus_t *hsdir_rs =NULL;
  
    tor_assert(onion_identity_pk);
  
    hsdir_rs = pick_hsdir_v3(onion_identity_pk);
    if (!hsdir_rs) {
      log_info(LD_REND, "Couldn't pick a v3 hsdir.");
      return HS_CLIENT_FETCH_NO_HSDIRS;
    }
  
    return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs);
  }
  
  /** With a given <b>onion_identity_pk</b>, fetch its descriptor. If
   * <b>hsdirs</b> is specified, use the directory servers specified in the list.
   * Else, use a random server. */
  void
  hs_client_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
                                 const smartlist_t *hsdirs)
  {
    tor_assert(onion_identity_pk);
  
    if (hsdirs != NULL) {
      SMARTLIST_FOREACH_BEGIN(hsdirs, const routerstatus_t *, hsdir) {
        directory_launch_v3_desc_fetch(onion_identity_pk, hsdir);
      } SMARTLIST_FOREACH_END(hsdir);
    } else {
      fetch_v3_desc(onion_identity_pk);
    }
  }
  
  /** Make sure that the given v3 origin circuit circ is a valid correct
   * introduction circuit. This will BUG() on any problems and hard assert if
   * the anonymity of the circuit is not ok. Return 0 on success else -1 where
   * the circuit should be mark for closed immediately. */
  static int
  intro_circ_is_ok(const origin_circuit_t *circ)
  {
    int ret = 0;
  
    tor_assert(circ);
  
    if (BUG(TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCING &&
            TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT &&
            TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACKED)) {
      ret = -1;
    }
    if (BUG(circ->hs_ident == NULL)) {
      ret = -1;
    }
    if (BUG(!hs_ident_intro_circ_is_valid(circ->hs_ident))) {
      ret = -1;
    }
  
    /* This can stop the tor daemon but we want that since if we don't have
     * anonymity on this circuit, something went really wrong. */
    assert_circ_anonymity_ok(circ, get_options());
    return ret;
  }
  
  /** Find a descriptor intro point object that matches the given ident in the
   * given descriptor desc. Return NULL if not found. */
  static const hs_desc_intro_point_t *
  find_desc_intro_point_by_ident(const hs_ident_circuit_t *ident,
                                 const hs_descriptor_t *desc)
  {
    const hs_desc_intro_point_t *intro_point = NULL;
  
    tor_assert(ident);
    tor_assert(desc);
  
    SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
                            const hs_desc_intro_point_t *, ip) {
      if (ed25519_pubkey_eq(&ident->intro_auth_pk,
                            &ip->auth_key_cert->signed_key)) {
        intro_point = ip;
        break;
      }
    } SMARTLIST_FOREACH_END(ip);
  
    return intro_point;
  }
  
  /** Find a descriptor intro point object from the descriptor object desc that
   * matches the given legacy identity digest in legacy_id. Return NULL if not
   * found. */
  static hs_desc_intro_point_t *
  find_desc_intro_point_by_legacy_id(const char *legacy_id,
                                     const hs_descriptor_t *desc)
  {
    hs_desc_intro_point_t *ret_ip = NULL;
  
    tor_assert(legacy_id);
    tor_assert(desc);
  
    /* We will go over every intro point and try to find which one is linked to
     * that circuit. Those lists are small so it's not that expensive. */
    SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
                            hs_desc_intro_point_t *, ip) {
      SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
                              const link_specifier_t *, lspec) {
        /* Not all tor node have an ed25519 identity key so we still rely on the
         * legacy identity digest. */
        if (link_specifier_get_ls_type(lspec) != LS_LEGACY_ID) {
          continue;
        }
        if (fast_memneq(legacy_id,
                        link_specifier_getconstarray_un_legacy_id(lspec),
                        DIGEST_LEN)) {
          break;
        }
        /* Found it. */
        ret_ip = ip;
        goto end;
      } SMARTLIST_FOREACH_END(lspec);
    } SMARTLIST_FOREACH_END(ip);
  
   end:
    return ret_ip;
  }
  
  /** Send an INTRODUCE1 cell along the intro circuit and populate the rend
   * circuit identifier with the needed key material for the e2e encryption.
   * Return 0 on success, -1 if there is a transient error such that an action
   * has been taken to recover and -2 if there is a permanent error indicating
   * that both circuits were closed. */
  static int
  send_introduce1(origin_circuit_t *intro_circ,
                  origin_circuit_t *rend_circ)
  {
    int status;
    char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
    const ed25519_public_key_t *service_identity_pk = NULL;
    const hs_desc_intro_point_t *ip;
  
    tor_assert(rend_circ);
    if (intro_circ_is_ok(intro_circ) < 0) {
      goto perm_err;
    }
  
    service_identity_pk = &intro_circ->hs_ident->identity_pk;
    /* For logging purposes. There will be a time where the hs_ident will have a
     * version number but for now there is none because it's all v3. */
    hs_build_address(service_identity_pk, HS_VERSION_THREE, onion_address);
  
    log_info(LD_REND, "Sending INTRODUCE1 cell to service %s on circuit %u",
             safe_str_client(onion_address), TO_CIRCUIT(intro_circ)->n_circ_id);
  
    /* 1) Get descriptor from our cache. */
    const hs_descriptor_t *desc =
      hs_cache_lookup_as_client(service_identity_pk);
    if (desc == NULL || !hs_client_any_intro_points_usable(service_identity_pk,
                                                           desc)) {
      log_info(LD_REND, "Request to %s %s. Trying to fetch a new descriptor.",
               safe_str_client(onion_address),
               (desc) ? "didn't have usable intro points" :
               "didn't have a descriptor");
      hs_client_refetch_hsdesc(service_identity_pk);
      /* We just triggered a refetch, make sure every connections are back
       * waiting for that descriptor. */
      flag_all_conn_wait_desc(service_identity_pk);
      /* We just asked for a refetch so this is a transient error. */
      goto tran_err;
    }
  
    /* We need to find which intro point in the descriptor we are connected to
     * on intro_circ. */
    ip = find_desc_intro_point_by_ident(intro_circ->hs_ident, desc);
    if (ip == NULL) {
      /* The following is possible if the descriptor was changed while we had
       * this introduction circuit open and waiting for the rendezvous circuit to
       * be ready. Which results in this situation where we can't find the
       * corresponding intro point within the descriptor of the service. */
      log_info(LD_REND, "Unable to find introduction point for service %s "
                        "while trying to send an INTRODUCE1 cell.",
               safe_str_client(onion_address));
      goto perm_err;
    }
  
    /* Send the INTRODUCE1 cell. */
    if (hs_circ_send_introduce1(intro_circ, rend_circ, ip,
                                &desc->subcredential) < 0) {
      if (TO_CIRCUIT(intro_circ)->marked_for_close) {
        /* If the introduction circuit was closed, we were unable to send the
         * cell for some reasons. In any case, the intro circuit has to be
         * closed by the above function. We'll return a transient error so tor
         * can recover and pick a new intro point. To avoid picking that same
         * intro point, we'll note down the intro point failure so it doesn't
         * get reused. */
        hs_cache_client_intro_state_note(service_identity_pk,
                                         &intro_circ->hs_ident->intro_auth_pk,
                                         INTRO_POINT_FAILURE_GENERIC);
      }
      /* It is also possible that the rendezvous circuit was closed due to being
       * unable to use the rendezvous point node_t so in that case, we also want
       * to recover and let tor pick a new one. */
      goto tran_err;
    }
  
    /* Cell has been sent successfully. Copy the introduction point
     * authentication and encryption key in the rendezvous circuit identifier so
     * we can compute the ntor keys when we receive the RENDEZVOUS2 cell. */
    memcpy(&rend_circ->hs_ident->intro_enc_pk, &ip->enc_key,
           sizeof(rend_circ->hs_ident->intro_enc_pk));
    ed25519_pubkey_copy(&rend_circ->hs_ident->intro_auth_pk,
                        &intro_circ->hs_ident->intro_auth_pk);
  
    /* Now, we wait for an ACK or NAK on this circuit. */
    circuit_change_purpose(TO_CIRCUIT(intro_circ),
                           CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT);
    /* Set timestamp_dirty, because circuit_expire_building expects it to
     * specify when a circuit entered the _C_INTRODUCE_ACK_WAIT state. */
    TO_CIRCUIT(intro_circ)->timestamp_dirty = time(NULL);
    pathbias_count_use_attempt(intro_circ);
  
    /* Success. */
    status = 0;
    goto end;
  
   perm_err:
    /* Permanent error: it is possible that the intro circuit was closed prior
     * because we weren't able to send the cell. Make sure we don't double close
     * it which would result in a warning. */
    if (!TO_CIRCUIT(intro_circ)->marked_for_close) {
      circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_INTERNAL);
    }
    circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_INTERNAL);
    status = -2;
    goto end;
  
   tran_err:
    status = -1;
  
   end:
    memwipe(onion_address, 0, sizeof(onion_address));
    return status;
  }
  
  /** Using the introduction circuit circ, setup the authentication key of the
   * intro point this circuit has extended to.
   *
   * Return 0 if everything went well, otherwise return -1 in the case of errors.
   */
  static int
  setup_intro_circ_auth_key(origin_circuit_t *circ)
  {
    const hs_descriptor_t *desc;
    const hs_desc_intro_point_t *ip;
  
    tor_assert(circ);
  
    desc = hs_cache_lookup_as_client(&circ->hs_ident->identity_pk);
    if (desc == NULL) {
      /* There is a very small race window between the opening of this circuit
       * and the client descriptor cache that gets purged (NEWNYM) or the
       * cleaned up because it expired. Mark the circuit for close so a new
       * descriptor fetch can occur. */
      goto err;
    }
  
    /* We will go over every intro point and try to find which one is linked to
     * that circuit. Those lists are small so it's not that expensive. */
    ip = find_desc_intro_point_by_legacy_id(
                         circ->build_state->chosen_exit->identity_digest, desc);
    if (!ip) {
      /* Reaching this point means we didn't find any intro point for this
       * circuit which is not supposed to happen. */
      log_info(LD_REND,"Could not match opened intro circuit with intro point.");
      goto err;
    }
  
    /* We got it, copy its authentication key to the identifier. */
    ed25519_pubkey_copy(&circ->hs_ident->intro_auth_pk,
                        &ip->auth_key_cert->signed_key);
    return 0;
  
   err:
    circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
    return -1;
  }
  
  /** Called when an introduction circuit has opened. */
  static void
  client_intro_circ_has_opened(origin_circuit_t *circ)
  {
    tor_assert(circ);
    tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
    log_info(LD_REND, "Introduction circuit %u has opened. Attaching streams.",
             (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
  
    /* This is an introduction circuit so we'll attach the correct
     * authentication key to the circuit identifier so it can be identified
     * properly later on. */
    if (setup_intro_circ_auth_key(circ) < 0) {
      return;
    }
  
    connection_ap_attach_pending(1);
  }
  
  /** Called when a rendezvous circuit has opened. */
  static void
  client_rendezvous_circ_has_opened(origin_circuit_t *circ)
  {
    tor_assert(circ);
    tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND);
  
    const extend_info_t *rp_ei = circ->build_state->chosen_exit;
  
    /* Check that we didn't accidentally choose a node that does not understand
     * the v3 rendezvous protocol */
    if (rp_ei) {
      const node_t *rp_node = node_get_by_id(rp_ei->identity_digest);
      if (rp_node && !node_supports_v3_rendezvous_point(rp_node)) {
        /* Even tho we checked that this node supported v3 when we created the
           rendezvous circuit, there is a chance that we might think it does
           not support v3 anymore. This might happen if we got a new consensus
           in the meanwhile, where the relay is still listed but its listed
           descriptor digest has changed and hence we can't access its 'ri' or
           'md'. */
        log_info(LD_REND, "Rendezvous node %s did not support v3 after circuit "
                 "has opened.", safe_str_client(extend_info_describe(rp_ei)));
        return;
      }
    }
  
    log_info(LD_REND, "Rendezvous circuit has opened to %s.",
             safe_str_client(extend_info_describe(rp_ei)));
  
    /* Ignore returned value, nothing we can really do. On failure, the circuit
     * will be marked for close. */
    hs_circ_send_establish_rendezvous(circ);
  
    /* Register rend circuit in circuitmap if it's still alive. */
    if (!TO_CIRCUIT(circ)->marked_for_close) {
      hs_circuitmap_register_rend_circ_client_side(circ,
                                       circ->hs_ident->rendezvous_cookie);
    }
  }
  
  /** This is an helper function that convert a descriptor intro point object ip
   * to a newly allocated extend_info_t object fully initialized. Return NULL if
   * we can't convert it for which chances are that we are missing or malformed
   * link specifiers. */
  STATIC extend_info_t *
  desc_intro_point_to_extend_info(const hs_desc_intro_point_t *ip)
  {
    extend_info_t *ei;
  
    tor_assert(ip);
  
    /* Explicitly put the direct connection option to 0 because this is client
     * side and there is no such thing as a non anonymous client. */
    ei = hs_get_extend_info_from_lspecs(ip->link_specifiers, &ip->onion_key, 0);
  
    return ei;
  }
  
  /** Return true iff the intro point ip for the service service_pk is usable.
   * This function checks if the intro point is in the client intro state cache
   * and checks at the failures. It is considered usable if:
   *   - No error happened (INTRO_POINT_FAILURE_GENERIC)
   *   - It is not flagged as timed out (INTRO_POINT_FAILURE_TIMEOUT)
   *   - The unreachable count is lower than
   *     MAX_INTRO_POINT_REACHABILITY_FAILURES (INTRO_POINT_FAILURE_UNREACHABLE)
   */
  static int
  intro_point_is_usable(const ed25519_public_key_t *service_pk,
                        const hs_desc_intro_point_t *ip)
  {
    const hs_cache_intro_state_t *state;
  
    tor_assert(service_pk);
    tor_assert(ip);
  
    state = hs_cache_client_intro_state_find(service_pk,
                                             &ip->auth_key_cert->signed_key);
    if (state == NULL) {
      /* This means we've never encountered any problem thus usable. */
      goto usable;
    }
    if (state->error) {
      log_info(LD_REND, "Intro point with auth key %s had an error. Not usable",
               safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
      goto not_usable;
    }
    if (state->timed_out) {
      log_info(LD_REND, "Intro point with auth key %s timed out. Not usable",
               safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
      goto not_usable;
    }
    if (state->unreachable_count >= MAX_INTRO_POINT_REACHABILITY_FAILURES) {
      log_info(LD_REND, "Intro point with auth key %s unreachable. Not usable",
               safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
      goto not_usable;
    }
  
   usable:
    return 1;
   not_usable:
    return 0;
  }
  
  /** Using a descriptor desc, return a newly allocated extend_info_t object of a
   * randomly picked introduction point from its list. Return NULL if none are
   * usable. */
  STATIC extend_info_t *
  client_get_random_intro(const ed25519_public_key_t *service_pk)
  {
    extend_info_t *ei = NULL, *ei_excluded = NULL;
    smartlist_t *usable_ips = NULL;
    const hs_descriptor_t *desc;
    const hs_desc_encrypted_data_t *enc_data;
    const or_options_t *options = get_options();
    /* Calculate the onion address for logging purposes */
    char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
  
    tor_assert(service_pk);
  
    desc = hs_cache_lookup_as_client(service_pk);
    /* Assume the service is v3 if the descriptor is missing. This is ok,
     * because we only use the address in log messages */
    hs_build_address(service_pk,
                     desc ? desc->plaintext_data.version : HS_VERSION_THREE,
                     onion_address);
    if (desc == NULL || !hs_client_any_intro_points_usable(service_pk,
                                                           desc)) {
      log_info(LD_REND, "Unable to randomly select an introduction point "
               "for service %s because descriptor %s. We can't connect.",
               safe_str_client(onion_address),
               (desc) ? "doesn't have any usable intro points"
                      : "is missing (assuming v3 onion address)");
      goto end;
    }
  
    enc_data = &desc->encrypted_data;
    usable_ips = smartlist_new();
    smartlist_add_all(usable_ips, enc_data->intro_points);
    while (smartlist_len(usable_ips) != 0) {
      int idx;
      const hs_desc_intro_point_t *ip;
  
      /* Pick a random intro point and immediately remove it from the usable
       * list so we don't pick it again if we have to iterate more. */
      idx = crypto_rand_int(smartlist_len(usable_ips));
      ip = smartlist_get(usable_ips, idx);
      smartlist_del(usable_ips, idx);
  
      /* We need to make sure we have a usable intro points which is in a good
       * state in our cache. */
      if (!intro_point_is_usable(service_pk, ip)) {
        continue;
      }
  
      /* Generate an extend info object from the intro point object. */
      ei = desc_intro_point_to_extend_info(ip);
      if (ei == NULL) {
        /* We can get here for instance if the intro point is a private address
         * and we aren't allowed to extend to those. */
        log_info(LD_REND, "Unable to select introduction point with auth key %s "
                 "for service %s, because we could not extend to it.",
                 safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)),
                 safe_str_client(onion_address));
        continue;
      }
  
      /* Test the pick against ExcludeNodes. */
      if (routerset_contains_extendinfo(options->ExcludeNodes, ei)) {
        /* If this pick is in the ExcludeNodes list, we keep its reference so if
         * we ever end up not being able to pick anything else and StrictNodes is
         * unset, we'll use it. */
        if (ei_excluded) {
          /* If something was already here free it. After the loop is gone we
           * will examine the last excluded intro point, and that's fine since
           * that's random anyway */
          extend_info_free(ei_excluded);
        }
        ei_excluded = ei;
        continue;
      }
  
      /* Good pick! Let's go with this. */
      goto end;
    }
  
    /* Reaching this point means a couple of things. Either we can't use any of
     * the intro point listed because the IP address can't be extended to or it
     * is listed in the ExcludeNodes list. In the later case, if StrictNodes is
     * set, we are forced to not use anything. */
    ei = ei_excluded;
    if (options->StrictNodes) {
      log_warn(LD_REND, "Every introduction point for service %s is in the "
               "ExcludeNodes set and StrictNodes is set. We can't connect.",
               safe_str_client(onion_address));
      extend_info_free(ei);
      ei = NULL;
    } else {
      log_fn(LOG_PROTOCOL_WARN, LD_REND, "Every introduction point for service "
             "%s is unusable or we can't extend to it. We can't connect.",
             safe_str_client(onion_address));
    }
  
   end:
    smartlist_free(usable_ips);
    memwipe(onion_address, 0, sizeof(onion_address));
    return ei;
  }
  
  /** Return true iff all intro points for the given service have timed out. */
  static bool
  intro_points_all_timed_out(const ed25519_public_key_t *service_pk)
  {
    bool ret = false;
  
    tor_assert(service_pk);
  
    const hs_descriptor_t *desc = hs_cache_lookup_as_client(service_pk);
    if (BUG(!desc)) {
      /* We can't introduce without a descriptor so ending up here means somehow
       * between the introduction failure and this, the cache entry was removed
       * which shouldn't be possible in theory. */
      goto end;
    }
  
    SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
                            const hs_desc_intro_point_t *, ip) {
      const hs_cache_intro_state_t *state =
        hs_cache_client_intro_state_find(service_pk,
                                         &ip->auth_key_cert->signed_key);
      if (!state || !state->timed_out) {
        /* No state or if this intro point has not timed out, we are done since
         * clearly not all of them have timed out. */
        goto end;
      }
    } SMARTLIST_FOREACH_END(ip);
  
    /* Exiting the loop here means that all intro points we've looked at have
     * timed out. Note that we can _not_ have a descriptor without intro points
     * in the client cache. */
    ret = true;
  
   end:
    return ret;
  }
  
  /** Called when a rendezvous circuit has timed out. Every stream attached to
   * the circuit will get set with the SOCKS5_HS_REND_FAILED (0xF3) extended
   * error code so if the connection to the rendezvous point ends up not
   * working, this code could be sent back as a reason. */
  static void
  socks_mark_rend_circuit_timed_out(const origin_circuit_t *rend_circ)
  {
    tor_assert(rend_circ);
  
    /* For each entry connection attached to this rendezvous circuit, report
     * the error. */
    for (edge_connection_t *edge = rend_circ->p_streams; edge;
         edge = edge->next_stream) {
       entry_connection_t *entry = EDGE_TO_ENTRY_CONN(edge);
       if (entry->socks_request) {
         entry->socks_request->socks_extended_error_code =
           SOCKS5_HS_REND_FAILED;
       }
    }
  }
  
  /** Called when introduction has failed meaning there is no more usable
   * introduction points to be used (either NACKed or failed) for the given
   * entry connection.
   *
   * This function only reports back the SOCKS5_HS_INTRO_FAILED (0xF2) code or
   * SOCKS5_HS_INTRO_TIMEDOUT (0xF7) if all intros have timed out. The caller
   * has to make sure to close the entry connections. */
  static void
  socks_mark_introduction_failed(entry_connection_t *conn,
                                   const ed25519_public_key_t *identity_pk)
  {
    socks5_reply_status_t code = SOCKS5_HS_INTRO_FAILED;
  
    tor_assert(conn);
    tor_assert(conn->socks_request);
    tor_assert(identity_pk);
  
    if (intro_points_all_timed_out(identity_pk)) {
      code = SOCKS5_HS_INTRO_TIMEDOUT;
    }
    conn->socks_request->socks_extended_error_code = code;
  }
  
  /** For this introduction circuit, we'll look at if we have any usable
   * introduction point left for this service. If so, we'll use the circuit to
   * re-extend to a new intro point. Else, we'll close the circuit and its
   * corresponding rendezvous circuit. Return 0 if we are re-extending else -1
   * if we are closing the circuits.
   *
   * This is called when getting an INTRODUCE_ACK cell with a NACK. */
  static int
  close_or_reextend_intro_circ(origin_circuit_t *intro_circ)
  {
    int ret = -1;
    const hs_descriptor_t *desc;
    origin_circuit_t *rend_circ;
  
    tor_assert(intro_circ);
  
    desc = hs_cache_lookup_as_client(&intro_circ->hs_ident->identity_pk);
    if (desc == NULL) {
      /* We can't continue without a descriptor. This is possible if the cache
       * was cleaned up between the intro point established and the reception of
       * the introduce ack. */
      goto close;
    }
    /* We still have the descriptor, great! Let's try to see if we can
     * re-extend by looking up if there are any usable intro points. */
    if (!hs_client_any_intro_points_usable(&intro_circ->hs_ident->identity_pk,
                                           desc)) {
      goto close;
    }
    /* Try to re-extend now. */
    if (hs_client_reextend_intro_circuit(intro_circ) < 0) {
      goto close;
    }
    /* Success on re-extending. Don't return an error. */
    ret = 0;
    goto end;
  
   close:
    /* Change the intro circuit purpose before so we don't report an intro point
     * failure again triggering an extra descriptor fetch. The circuit can
     * already be closed on failure to re-extend. */
    if (!TO_CIRCUIT(intro_circ)->marked_for_close) {
      circuit_change_purpose(TO_CIRCUIT(intro_circ),
                             CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
      circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED);
    }
    /* Close the related rendezvous circuit. */
    rend_circ = hs_circuitmap_get_rend_circ_client_side(
                                       intro_circ->hs_ident->rendezvous_cookie);
    /* The rendezvous circuit might have collapsed while the INTRODUCE_ACK was
     * inflight so we can't expect one every time. */
    if (rend_circ) {
      circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_FINISHED);
    }
  
   end:
    return ret;
  }
  
  /** Called when we get an INTRODUCE_ACK success status code. Do the appropriate
   * actions for the rendezvous point and finally close intro_circ. */
  static void
  handle_introduce_ack_success(origin_circuit_t *intro_circ)
  {
    origin_circuit_t *rend_circ = NULL;
  
    tor_assert(intro_circ);
  
    log_info(LD_REND, "Received INTRODUCE_ACK ack! Informing rendezvous");
  
    /* Get the rendezvous circuit for this rendezvous cookie. */
    uint8_t *rendezvous_cookie = intro_circ->hs_ident->rendezvous_cookie;
    rend_circ =
    hs_circuitmap_get_established_rend_circ_client_side(rendezvous_cookie);
    if (rend_circ == NULL) {
      log_warn(LD_REND, "Can't find any rendezvous circuit. Stopping");
      goto end;
    }
  
    assert_circ_anonymity_ok(rend_circ, get_options());
  
    /* It is possible to get a RENDEZVOUS2 cell before the INTRODUCE_ACK which
     * means that the circuit will be joined and already transmitting data. In
     * that case, simply skip the purpose change and close the intro circuit
     * like it should be. */
    if (TO_CIRCUIT(rend_circ)->purpose == CIRCUIT_PURPOSE_C_REND_JOINED) {
      goto end;
    }
    circuit_change_purpose(TO_CIRCUIT(rend_circ),
                           CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED);
    /* Set timestamp_dirty, because circuit_expire_building expects it to
     * specify when a circuit entered the
     * CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED state. */
    TO_CIRCUIT(rend_circ)->timestamp_dirty = time(NULL);
  
   end:
    /* We don't need the intro circuit anymore. It did what it had to do! */
    circuit_change_purpose(TO_CIRCUIT(intro_circ),
                           CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
    circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED);
  
    /* XXX: Close pending intro circuits we might have in parallel. */
    return;
  }
  
  /** Called when we get an INTRODUCE_ACK failure status code. Depending on our
   * failure cache status, either close the circuit or re-extend to a new
   * introduction point. */
  static void
  handle_introduce_ack_bad(origin_circuit_t *circ, int status)
  {
    tor_assert(circ);
  
    log_info(LD_REND, "Received INTRODUCE_ACK nack by %s. Reason: %u",
        safe_str_client(extend_info_describe(circ->build_state->chosen_exit)),
        status);
  
    /* It's a NAK. The introduction point didn't relay our request. */
    circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_INTRODUCING);
  
    /* Note down this failure in the intro point failure cache. Depending on how
     * many times we've tried this intro point, close it or reextend. */
    hs_cache_client_intro_state_note(&circ->hs_ident->identity_pk,
                                     &circ->hs_ident->intro_auth_pk,
                                     INTRO_POINT_FAILURE_GENERIC);
  }
  
  /** Called when we get an INTRODUCE_ACK on the intro circuit circ. The encoded
   * cell is in payload of length payload_len. Return 0 on success else a
   * negative value. The circuit is either close or reuse to re-extend to a new
   * introduction point. */
  static int
  handle_introduce_ack(origin_circuit_t *circ, const uint8_t *payload,
                       size_t payload_len)
  {
    int status, ret = -1;
  
    tor_assert(circ);
    tor_assert(circ->build_state);
    tor_assert(circ->build_state->chosen_exit);
    assert_circ_anonymity_ok(circ, get_options());
    tor_assert(payload);
  
    status = hs_cell_parse_introduce_ack(payload, payload_len);
    switch (status) {
    case TRUNNEL_HS_INTRO_ACK_STATUS_SUCCESS:
      ret = 0;
      handle_introduce_ack_success(circ);
      goto end;
    case TRUNNEL_HS_INTRO_ACK_STATUS_UNKNOWN_ID:
    case TRUNNEL_HS_INTRO_ACK_STATUS_BAD_FORMAT:
    /* It is possible that the intro point can send us an unknown status code
     * for the NACK that we do not know about like a new code for instance.
     * Just fallthrough so we can note down the NACK and re-extend. */
    default:
      handle_introduce_ack_bad(circ, status);
      /* We are going to see if we have to close the circuits (IP and RP) or we
       * can re-extend to a new intro point. */
      ret = close_or_reextend_intro_circ(circ);
      break;
    }
  
   end:
    return ret;
  }
  
  /** Called when we get a RENDEZVOUS2 cell on the rendezvous circuit circ. The
   * encoded cell is in payload of length payload_len. Return 0 on success or a
   * negative value on error. On error, the circuit is marked for close. */
  STATIC int
  handle_rendezvous2(origin_circuit_t *circ, const uint8_t *payload,
                     size_t payload_len)
  {
    int ret = -1;
    curve25519_public_key_t server_pk;
    uint8_t auth_mac[DIGEST256_LEN] = {0};
    uint8_t handshake_info[CURVE25519_PUBKEY_LEN + sizeof(auth_mac)] = {0};
    hs_ntor_rend_cell_keys_t keys;
    const hs_ident_circuit_t *ident;
  
    tor_assert(circ);
    tor_assert(payload);
  
    /* Make things easier. */
    ident = circ->hs_ident;
    tor_assert(ident);
  
    if (hs_cell_parse_rendezvous2(payload, payload_len, handshake_info,
                                  sizeof(handshake_info)) < 0) {
      goto err;
    }
    /* Get from the handshake info the SERVER_PK and AUTH_MAC. */
    memcpy(&server_pk, handshake_info, CURVE25519_PUBKEY_LEN);
    memcpy(auth_mac, handshake_info + CURVE25519_PUBKEY_LEN, sizeof(auth_mac));
  
    /* Generate the handshake info. */
    if (hs_ntor_client_get_rendezvous1_keys(&ident->intro_auth_pk,
                                            &ident->rendezvous_client_kp,
                                            &ident->intro_enc_pk, &server_pk,
                                            &keys) < 0) {
      log_info(LD_REND, "Unable to compute the rendezvous keys.");
      goto err;
    }
  
    /* Critical check, make sure that the MAC matches what we got with what we
     * computed just above. */
    if (!hs_ntor_client_rendezvous2_mac_is_good(&keys, auth_mac)) {
      log_info(LD_REND, "Invalid MAC in RENDEZVOUS2. Rejecting cell.");
      goto err;
    }
  
    /* Setup the e2e encryption on the circuit and finalize its state. */
    if (hs_circuit_setup_e2e_rend_circ(circ, keys.ntor_key_seed,
                                       sizeof(keys.ntor_key_seed), 0) < 0) {
      log_info(LD_REND, "Unable to setup the e2e encryption.");
      goto err;
    }
    /* Success. Hidden service connection finalized! */
    ret = 0;
    goto end;
  
   err:
    circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
   end:
    memwipe(&keys, 0, sizeof(keys));
    return ret;
  }
  
  /** Return true iff the client can fetch a descriptor for this service public
   * identity key and status_out if not NULL is untouched. If the client can
   * _not_ fetch the descriptor and if status_out is not NULL, it is set with
   * the fetch status code. */
  static unsigned int
  can_client_refetch_desc(const ed25519_public_key_t *identity_pk,
                          hs_client_fetch_status_t *status_out)
  {
    hs_client_fetch_status_t status;
  
    tor_assert(identity_pk);
  
    /* Are we configured to fetch descriptors? */
    if (!get_options()->FetchHidServDescriptors) {
      log_warn(LD_REND, "We received an onion address for a hidden service "
                        "descriptor but we are configured to not fetch.");
      status = HS_CLIENT_FETCH_NOT_ALLOWED;
      goto cannot;
    }
  
    /* Without a live consensus we can't do any client actions. It is needed to
     * compute the hashring for a service. */
    if (!networkstatus_get_live_consensus(approx_time())) {
      log_info(LD_REND, "Can't fetch descriptor for service %s because we "
                        "are missing a live consensus. Stalling connection.",
               safe_str_client(ed25519_fmt(identity_pk)));
      status = HS_CLIENT_FETCH_MISSING_INFO;
      goto cannot;
    }
  
    if (!router_have_minimum_dir_info()) {
      log_info(LD_REND, "Can't fetch descriptor for service %s because we "
                        "dont have enough descriptors. Stalling connection.",
               safe_str_client(ed25519_fmt(identity_pk)));
      status = HS_CLIENT_FETCH_MISSING_INFO;
      goto cannot;
    }
  
    /* Check if fetching a desc for this HS is useful to us right now */
    {
      const hs_descriptor_t *cached_desc = NULL;
      cached_desc = hs_cache_lookup_as_client(identity_pk);
      if (cached_desc && hs_client_any_intro_points_usable(identity_pk,
                                                           cached_desc)) {
        log_info(LD_GENERAL, "We would fetch a v3 hidden service descriptor "
                             "but we already have a usable descriptor.");
        status = HS_CLIENT_FETCH_HAVE_DESC;
        goto cannot;
      }
    }
  
    /* Don't try to refetch while we have a pending request for it. */
    if (directory_request_is_pending(identity_pk)) {
      log_info(LD_REND, "Already a pending directory request. Waiting on it.");
      status = HS_CLIENT_FETCH_PENDING;
      goto cannot;
    }
  
    /* Yes, client can fetch! */
    return 1;
   cannot:
    if (status_out) {
      *status_out = status;
    }
    return 0;
  }
  
  /** Purge the client authorization cache of all ephemeral entries that is the
   * entries that are not flagged with CLIENT_AUTH_FLAG_IS_PERMANENT.
   *
   * This is called from the hs_client_purge_state() used by a SIGNEWNYM. */
  STATIC void
  purge_ephemeral_client_auth(void)
  {
    DIGEST256MAP_FOREACH_MODIFY(client_auths, key,
                                hs_client_service_authorization_t *, auth) {
      /* Cleanup every entry that are _NOT_ permanent that is ephemeral. */
      if (!(auth->flags & CLIENT_AUTH_FLAG_IS_PERMANENT)) {
        MAP_DEL_CURRENT(key);
        client_service_authorization_free(auth);
      }
    } DIGESTMAP_FOREACH_END;
  
    log_info(LD_REND, "Client onion service ephemeral authorization "
                      "cache has been purged.");
  }
  
  /** Return the client auth in the map using the service identity public key.
   * Return NULL if it does not exist in the map. */
  static hs_client_service_authorization_t *
  find_client_auth(const ed25519_public_key_t *service_identity_pk)
  {
    /* If the map is not allocated, we can assume that we do not have any client
     * auth information. */
    if (!client_auths) {
      return NULL;
    }
    return digest256map_get(client_auths, service_identity_pk->pubkey);
  }
  
  /** This is called when a descriptor has arrived following a fetch request and
   * has been stored in the client cache. The given entry connections, matching
   * the service identity key, will get attached to the service circuit. */
  static void
  client_desc_has_arrived(const smartlist_t *entry_conns)
  {
    time_t now = time(NULL);
  
    tor_assert(entry_conns);
  
    SMARTLIST_FOREACH_BEGIN(entry_conns, entry_connection_t *, entry_conn) {
      const hs_descriptor_t *desc;
      edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
      const ed25519_public_key_t *identity_pk =
        &edge_conn->hs_ident->identity_pk;
  
      /* We were just called because we stored the descriptor for this service
       * so not finding a descriptor means we have a bigger problem. */
      desc = hs_cache_lookup_as_client(identity_pk);
      if (BUG(desc == NULL)) {
        goto end;
      }
  
      if (!hs_client_any_intro_points_usable(identity_pk, desc)) {
        log_info(LD_REND, "Hidden service descriptor is unusable. "
                          "Closing streams.");
        /* Report the extended socks error code that we were unable to introduce
         * to the service. */
        socks_mark_introduction_failed(entry_conn, identity_pk);
  
        connection_mark_unattached_ap(entry_conn,
                                      END_STREAM_REASON_RESOLVEFAILED);
        /* We are unable to use the descriptor so remove the directory request
         * from the cache so the next connection can try again. */
        note_connection_attempt_succeeded(edge_conn->hs_ident);
        continue;
      }
  
      log_info(LD_REND, "Descriptor has arrived. Launching circuits.");
  
      /* Mark connection as waiting for a circuit since we do have a usable
       * descriptor now. */
      mark_conn_as_waiting_for_circuit(&edge_conn->base_, now);
    } SMARTLIST_FOREACH_END(entry_conn);
  
   end:
    return;
  }
  
  /** This is called when a descriptor fetch was successful but the descriptor
   * couldn't be decrypted due to missing or bad client authorization. */
  static void
  client_desc_missing_bad_client_auth(const smartlist_t *entry_conns,
                                      hs_desc_decode_status_t status)
  {
    tor_assert(entry_conns);
  
    SMARTLIST_FOREACH_BEGIN(entry_conns, entry_connection_t *, entry_conn) {
      socks5_reply_status_t code;
      if (status == HS_DESC_DECODE_BAD_CLIENT_AUTH) {
        code = SOCKS5_HS_BAD_CLIENT_AUTH;
      } else if (status == HS_DESC_DECODE_NEED_CLIENT_AUTH) {
        code = SOCKS5_HS_MISSING_CLIENT_AUTH;
      } else {
        /* We should not be called with another type of status. Recover by
         * sending a generic error. */
        tor_assert_nonfatal_unreached();
        code = SOCKS5_GENERAL_ERROR;
      }
      entry_conn->socks_request->socks_extended_error_code = code;
      connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_MISC);
    } SMARTLIST_FOREACH_END(entry_conn);
  }
  
  /** Called when we get a 200 directory fetch status code. */
  static void
  client_dir_fetch_200(dir_connection_t *dir_conn,
                       const smartlist_t *entry_conns, const char *body)
  {
    hs_desc_decode_status_t decode_status;
  
    tor_assert(dir_conn);
    tor_assert(entry_conns);
    tor_assert(body);
  
    /* We got something: Try storing it in the cache. */
    decode_status = hs_cache_store_as_client(body,
                                             &dir_conn->hs_ident->identity_pk);
    switch (decode_status) {
    case HS_DESC_DECODE_OK:
    case HS_DESC_DECODE_NEED_CLIENT_AUTH:
    case HS_DESC_DECODE_BAD_CLIENT_AUTH:
      log_info(LD_REND, "Stored hidden service descriptor successfully.");
      TO_CONN(dir_conn)->purpose = DIR_PURPOSE_HAS_FETCHED_HSDESC;
      if (decode_status == HS_DESC_DECODE_OK) {
        client_desc_has_arrived(entry_conns);
      } else {
        /* This handles both client auth decode status. */
        client_desc_missing_bad_client_auth(entry_conns, decode_status);
        log_info(LD_REND, "Stored hidden service descriptor requires "
                           "%s client authorization.",
                 decode_status == HS_DESC_DECODE_NEED_CLIENT_AUTH ? "missing"
                                                                  : "new");
      }
      /* Fire control port RECEIVED event. */
      hs_control_desc_event_received(dir_conn->hs_ident,
                                     dir_conn->identity_digest);
      hs_control_desc_event_content(dir_conn->hs_ident,
                                    dir_conn->identity_digest, body);
      break;
    case HS_DESC_DECODE_ENCRYPTED_ERROR:
    case HS_DESC_DECODE_SUPERENC_ERROR:
    case HS_DESC_DECODE_PLAINTEXT_ERROR:
    case HS_DESC_DECODE_GENERIC_ERROR:
    default:
      log_info(LD_REND, "Failed to store hidden service descriptor. "
                        "Descriptor decoding status: %d", decode_status);
      /* Fire control port FAILED event. */
      hs_control_desc_event_failed(dir_conn->hs_ident,
                                   dir_conn->identity_digest, "BAD_DESC");
      hs_control_desc_event_content(dir_conn->hs_ident,
                                    dir_conn->identity_digest, NULL);
      break;
    }
  }
  
  /** Called when we get a 404 directory fetch status code. */
  static void
  client_dir_fetch_404(dir_connection_t *dir_conn,
                       const smartlist_t *entry_conns)
  {
    tor_assert(entry_conns);
  
    /* Not there. We'll retry when connection_about_to_close_connection() tries
     * to clean this conn up. */
    log_info(LD_REND, "Fetching hidden service v3 descriptor not found: "
                      "Retrying at another directory.");
    /* Fire control port FAILED event. */
    hs_control_desc_event_failed(dir_conn->hs_ident, dir_conn->identity_digest,
                                 "NOT_FOUND");
    hs_control_desc_event_content(dir_conn->hs_ident, dir_conn->identity_digest,
                                  NULL);
  
    /* Flag every entry connections that the descriptor was not found. */
    SMARTLIST_FOREACH_BEGIN(entry_conns, entry_connection_t *, entry_conn) {
      entry_conn->socks_request->socks_extended_error_code =
        SOCKS5_HS_NOT_FOUND;
    } SMARTLIST_FOREACH_END(entry_conn);
  }
  
  /** Called when we get a 400 directory fetch status code. */
  static void
  client_dir_fetch_400(dir_connection_t *dir_conn, const char *reason)
  {
    tor_assert(dir_conn);
  
    log_warn(LD_REND, "Fetching v3 hidden service descriptor failed: "
                      "http status 400 (%s). Dirserver didn't like our "
                      "query? Retrying at another directory.",
             escaped(reason));
  
    /* Fire control port FAILED event. */
    hs_control_desc_event_failed(dir_conn->hs_ident, dir_conn->identity_digest,
                                 "QUERY_REJECTED");
    hs_control_desc_event_content(dir_conn->hs_ident, dir_conn->identity_digest,
                                  NULL);
  }
  
  /** Called when we get an unexpected directory fetch status code. */
  static void
  client_dir_fetch_unexpected(dir_connection_t *dir_conn, const char *reason,
                              const int status_code)
  {
    tor_assert(dir_conn);
  
    log_warn(LD_REND, "Fetching v3 hidden service descriptor failed: "
                      "http status %d (%s) response unexpected from HSDir "
                      "server %s'. Retrying at another directory.",
             status_code, escaped(reason),
             connection_describe_peer(TO_CONN(dir_conn)));
    /* Fire control port FAILED event. */
    hs_control_desc_event_failed(dir_conn->hs_ident, dir_conn->identity_digest,
                                 "UNEXPECTED");
    hs_control_desc_event_content(dir_conn->hs_ident, dir_conn->identity_digest,
                                  NULL);
  }
  
  /** Get the full filename for storing the client auth credentials for the
   *  service in <b>onion_address</b>. The base directory is <b>dir</b>.
   *  This function never returns NULL. */
  static char *
  get_client_auth_creds_filename(const char *onion_address,
                                 const char *dir)
  {
    char *full_fname = NULL;
    char *fname;
  
    tor_asprintf(&fname, "%s.auth_private", onion_address);
    full_fname = hs_path_from_filename(dir, fname);
    tor_free(fname);
  
    return full_fname;
  }
  
  /** Permanently store the credentials in <b>creds</b> to disk.
   *
   *  Return -1 if there was an error while storing the credentials, otherwise
   *  return 0.
   */
  static int
  store_permanent_client_auth_credentials(
                                const hs_client_service_authorization_t *creds)
  {
    const or_options_t *options = get_options();
    char *full_fname = NULL;
    char *file_contents = NULL;
    char priv_key_b32[BASE32_NOPAD_LEN(CURVE25519_PUBKEY_LEN)+1];
    int retval = -1;
  
    tor_assert(creds->flags & CLIENT_AUTH_FLAG_IS_PERMANENT);
  
    /* We need ClientOnionAuthDir to be set, otherwise we can't proceed */
    if (!options->ClientOnionAuthDir) {
      log_warn(LD_GENERAL, "Can't register permanent client auth credentials "
               "for %s without ClientOnionAuthDir option. Discarding.",
               creds->onion_address);
      goto err;
    }
  
    /* Make sure the directory exists and is private enough. */
    if (check_private_dir(options->ClientOnionAuthDir, 0, options->User) < 0) {
      goto err;
    }
  
    /* Get filename that we should store the credentials */
    full_fname = get_client_auth_creds_filename(creds->onion_address,
                                                options->ClientOnionAuthDir);
  
    /* Encode client private key */
    base32_encode(priv_key_b32, sizeof(priv_key_b32),
                  (char*)creds->enc_seckey.secret_key,
                  sizeof(creds->enc_seckey.secret_key));
  
    /* Get the full file contents and write it to disk! */
    tor_asprintf(&file_contents, "%s:descriptor:x25519:%s",
                 creds->onion_address, priv_key_b32);
    if (write_str_to_file(full_fname, file_contents, 0) < 0) {
      log_warn(LD_GENERAL, "Failed to write client auth creds file for %s!",
               creds->onion_address);
      goto err;
    }
  
    retval = 0;
  
   err:
    tor_free(file_contents);
    tor_free(full_fname);
  
    return retval;
  }
  
  /** Register the credential <b>creds</b> as part of the client auth subsystem.
   *
   * Takes ownership of <b>creds</b>.
   **/
  hs_client_register_auth_status_t
  hs_client_register_auth_credentials(hs_client_service_authorization_t *creds)
  {
    ed25519_public_key_t service_identity_pk;
    hs_client_service_authorization_t *old_creds = NULL;
    hs_client_register_auth_status_t retval = REGISTER_SUCCESS;
  
    tor_assert(creds);
  
    if (!client_auths) {
      client_auths = digest256map_new();
    }
  
    if (hs_parse_address(creds->onion_address, &service_identity_pk,
                         NULL, NULL) < 0) {
      client_service_authorization_free(creds);
      return REGISTER_FAIL_BAD_ADDRESS;
    }
  
    /* If we reach this point, the credentials will be stored one way or another:
     * Make them permanent if the user asked us to. */
    if (creds->flags & CLIENT_AUTH_FLAG_IS_PERMANENT) {
      if (store_permanent_client_auth_credentials(creds) < 0) {
        client_service_authorization_free(creds);
        return REGISTER_FAIL_PERMANENT_STORAGE;
      }
    }
  
    old_creds = digest256map_get(client_auths, service_identity_pk.pubkey);
    if (old_creds) {
      digest256map_remove(client_auths, service_identity_pk.pubkey);
      client_service_authorization_free(old_creds);
      retval = REGISTER_SUCCESS_ALREADY_EXISTS;
    }
  
    digest256map_set(client_auths, service_identity_pk.pubkey, creds);
  
    /** Now that we set the new credentials, also try to decrypt any cached
     *  descriptors. */
    if (hs_cache_client_new_auth_parse(&service_identity_pk)) {
      retval = REGISTER_SUCCESS_AND_DECRYPTED;
    }
  
    return retval;
  }
  
  /** Load a client authorization file with <b>filename</b> that is stored under
   *  the global client auth directory, and return a newly-allocated credentials
   *  object if it parsed well. Otherwise, return NULL.
   */
  static hs_client_service_authorization_t *
  get_creds_from_client_auth_filename(const char *filename,
                                      const or_options_t *options)
  {
    hs_client_service_authorization_t *auth = NULL;
    char *client_key_file_path = NULL;
    char *client_key_str = NULL;
  
    log_info(LD_REND, "Loading a client authorization key file %s...",
             filename);
  
    if (!auth_key_filename_is_valid(filename)) {
      log_notice(LD_REND, "Client authorization unrecognized filename %s. "
                 "File must end in .auth_private. Ignoring.",
                 filename);
      goto err;
    }
  
    /* Create a full path for a file. */
    client_key_file_path = hs_path_from_filename(options->ClientOnionAuthDir,
                                                 filename);
  
    client_key_str = read_file_to_str(client_key_file_path, 0, NULL);
    if (!client_key_str) {
      log_warn(LD_REND, "The file %s cannot be read.", filename);
      goto err;
    }
  
    auth = parse_auth_file_content(client_key_str);
    if (!auth) {
      goto err;
    }
  
   err:
    tor_free(client_key_str);
    tor_free(client_key_file_path);
  
    return auth;
  }
  
  /*
   * Remove the file in <b>filename</b> under the global client auth credential
   * storage.
   */
  static void
  remove_client_auth_creds_file(const char *filename)
  {
    char *creds_file_path = NULL;
    const or_options_t *options = get_options();
  
    creds_file_path = hs_path_from_filename(options->ClientOnionAuthDir,
                                            filename);
    if (tor_unlink(creds_file_path) != 0) {
      log_warn(LD_REND, "Failed to remove client auth file (%s).",
               creds_file_path);
      goto end;
    }
  
    log_warn(LD_REND, "Successfuly removed client auth file (%s).",
             creds_file_path);
  
   end:
    tor_free(creds_file_path);
  }
  
  /**
   * Find the filesystem file corresponding to the permanent client auth
   * credentials in <b>cred</b> and remove it.
   */
  static void
  find_and_remove_client_auth_creds_file(
                                   const hs_client_service_authorization_t *cred)
  {
    smartlist_t *file_list = NULL;
    const or_options_t *options = get_options();
  
    tor_assert(cred->flags & CLIENT_AUTH_FLAG_IS_PERMANENT);
  
    if (!options->ClientOnionAuthDir) {
      log_warn(LD_REND, "Found permanent credential but no ClientOnionAuthDir "
               "configured. There is no file to be removed.");
      goto end;
    }
  
    file_list = tor_listdir(options->ClientOnionAuthDir);
    if (file_list == NULL) {
      log_warn(LD_REND, "Client authorization key directory %s can't be listed.",
               options->ClientOnionAuthDir);
      goto end;
    }
  
    SMARTLIST_FOREACH_BEGIN(file_list, const char *, filename) {
      hs_client_service_authorization_t *tmp_cred = NULL;
  
      tmp_cred = get_creds_from_client_auth_filename(filename, options);
      if (!tmp_cred) {
        continue;
      }
  
      /* Find the right file for this credential */
      if (!strcmp(tmp_cred->onion_address, cred->onion_address)) {
        /* Found it! Remove the file! */
        remove_client_auth_creds_file(filename);
        /* cleanup and get out of here */
        client_service_authorization_free(tmp_cred);
        break;
      }
  
      client_service_authorization_free(tmp_cred);
    } SMARTLIST_FOREACH_END(filename);
  
   end:
    if (file_list) {
      SMARTLIST_FOREACH(file_list, char *, s, tor_free(s));
      smartlist_free(file_list);
    }
  }
  
  /** Remove client auth credentials for the service <b>hs_address</b>. */
  hs_client_removal_auth_status_t
  hs_client_remove_auth_credentials(const char *hsaddress)
  {
    ed25519_public_key_t service_identity_pk;
  
    if (!client_auths) {
      return REMOVAL_SUCCESS_NOT_FOUND;
    }
  
    if (hs_parse_address(hsaddress, &service_identity_pk, NULL, NULL) < 0) {
      return REMOVAL_BAD_ADDRESS;
    }
  
    hs_client_service_authorization_t *cred = NULL;
    cred = digest256map_remove(client_auths, service_identity_pk.pubkey);
  
    /* digestmap_remove() returns the previously stored data if there were any */
    if (cred) {
      if (cred->flags & CLIENT_AUTH_FLAG_IS_PERMANENT) {
        /* These creds are stored on disk: remove the corresponding file. */
        find_and_remove_client_auth_creds_file(cred);
      }
  
      /* Remove associated descriptor if any. */
      hs_cache_remove_as_client(&service_identity_pk);
  
      client_service_authorization_free(cred);
      return REMOVAL_SUCCESS;
    }
  
    return REMOVAL_SUCCESS_NOT_FOUND;
  }
  
  /** Get the HS client auth map. */
  digest256map_t *
  get_hs_client_auths_map(void)
  {
    return client_auths;
  }
  
  /* ========== */
  /* Public API */
  /* ========== */
  
  /** Called when a circuit was just cleaned up. This is done right before the
   * circuit is marked for close. */
  void
  hs_client_circuit_cleanup_on_close(const circuit_t *circ)
  {
    bool has_timed_out;
  
    tor_assert(circ);
    tor_assert(CIRCUIT_IS_ORIGIN(circ));
  
    has_timed_out =
      (circ->marked_for_close_orig_reason == END_CIRC_REASON_TIMEOUT);
  
    switch (circ->purpose) {
    case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
    case CIRCUIT_PURPOSE_C_REND_READY:
    case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED:
    case CIRCUIT_PURPOSE_C_REND_JOINED:
      /* Report extended SOCKS error code when a rendezvous circuit times out.
       * This MUST be done on_close() because it is possible the entry
       * connection would get closed before the circuit is freed and thus
       * would fail to report the error code. */
      if (has_timed_out) {
        socks_mark_rend_circuit_timed_out(CONST_TO_ORIGIN_CIRCUIT(circ));
      }
      break;
    default:
      break;
    }
  }
  
  /** Called when a circuit was just cleaned up. This is done right before the
   * circuit is freed. */
  void
  hs_client_circuit_cleanup_on_free(const circuit_t *circ)
  {
    bool has_timed_out;
    rend_intro_point_failure_t failure = INTRO_POINT_FAILURE_GENERIC;
    const origin_circuit_t *orig_circ = NULL;
  
    tor_assert(circ);
    tor_assert(CIRCUIT_IS_ORIGIN(circ));
  
    orig_circ = CONST_TO_ORIGIN_CIRCUIT(circ);
    tor_assert(orig_circ->hs_ident);
  
    has_timed_out =
      (circ->marked_for_close_orig_reason == END_CIRC_REASON_TIMEOUT);
    if (has_timed_out) {
      failure = INTRO_POINT_FAILURE_TIMEOUT;
    }
  
    switch (circ->purpose) {
    case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT:
      log_info(LD_REND, "Failed v3 intro circ for service %s to intro point %s "
                        "(awaiting ACK). Failure code: %d",
          safe_str_client(ed25519_fmt(&orig_circ->hs_ident->identity_pk)),
          safe_str_client(build_state_get_exit_nickname(orig_circ->build_state)),
          failure);
      hs_cache_client_intro_state_note(&orig_circ->hs_ident->identity_pk,
                                       &orig_circ->hs_ident->intro_auth_pk,
                                       failure);
      break;
    case CIRCUIT_PURPOSE_C_INTRODUCING:
      if (has_timed_out || !orig_circ->build_state) {
        break;
      }
      failure = INTRO_POINT_FAILURE_UNREACHABLE;
      log_info(LD_REND, "Failed v3 intro circ for service %s to intro point %s "
                        "(while building circuit). Marking as unreachable.",
         safe_str_client(ed25519_fmt(&orig_circ->hs_ident->identity_pk)),
         safe_str_client(build_state_get_exit_nickname(orig_circ->build_state)));
      hs_cache_client_intro_state_note(&orig_circ->hs_ident->identity_pk,
                                       &orig_circ->hs_ident->intro_auth_pk,
                                       failure);
      break;
    default:
      break;
    }
  }
  
  /** A circuit just finished connecting to a hidden service that the stream
   *  <b>conn</b> has been waiting for. Let the HS subsystem know about this. */
  void
  hs_client_note_connection_attempt_succeeded(const edge_connection_t *conn)
  {
    tor_assert(connection_edge_is_rendezvous_stream(conn));
  
    if (BUG(conn->rend_data && conn->hs_ident)) {
      log_warn(LD_BUG, "Stream had both rend_data and hs_ident..."
               "Prioritizing hs_ident");
    }
  
    if (conn->hs_ident) { /* It's v3: pass it to the prop224 handler */
      note_connection_attempt_succeeded(conn->hs_ident);
      return;
    } else if (conn->rend_data) { /* It's v2: pass it to the legacy handler */
      rend_client_note_connection_attempt_ended(conn->rend_data);
      return;
    }
  }
  
  /** With the given encoded descriptor in desc_str and the service key in
   * service_identity_pk, decode the descriptor and set the desc pointer with a
   * newly allocated descriptor object.
   *
   * On success, HS_DESC_DECODE_OK is returned and desc is set to the decoded
   * descriptor. On error, desc is set to NULL and a decoding error status is
   * returned depending on what was the issue. */
  hs_desc_decode_status_t
  hs_client_decode_descriptor(const char *desc_str,
                              const ed25519_public_key_t *service_identity_pk,
                              hs_descriptor_t **desc)
  {
    hs_desc_decode_status_t ret;
    hs_subcredential_t subcredential;
    ed25519_public_key_t blinded_pubkey;
    hs_client_service_authorization_t *client_auth = NULL;
    curve25519_secret_key_t *client_auth_sk = NULL;
  
    tor_assert(desc_str);
    tor_assert(service_identity_pk);
    tor_assert(desc);
  
    /* Check if we have a client authorization for this service in the map. */
    client_auth = find_client_auth(service_identity_pk);
    if (client_auth) {
      client_auth_sk = &client_auth->enc_seckey;
    }
  
    /* Create subcredential for this HS so that we can decrypt */
    {
      uint64_t current_time_period = hs_get_time_period_num(0);
      hs_build_blinded_pubkey(service_identity_pk, NULL, 0, current_time_period,
                              &blinded_pubkey);
      hs_get_subcredential(service_identity_pk, &blinded_pubkey, &subcredential);
    }
  
    /* Parse descriptor */
    ret = hs_desc_decode_descriptor(desc_str, &subcredential,
                                    client_auth_sk, desc);
    memwipe(&subcredential, 0, sizeof(subcredential));
    if (ret != HS_DESC_DECODE_OK) {
      goto err;
    }
  
    /* Make sure the descriptor signing key cross certifies with the computed
     * blinded key. Without this validation, anyone knowing the subcredential
     * and onion address can forge a descriptor. */
    tor_cert_t *cert = (*desc)->plaintext_data.signing_key_cert;
    if (tor_cert_checksig(cert,
                          &blinded_pubkey, approx_time()) < 0) {
      log_warn(LD_GENERAL, "Descriptor signing key certificate signature "
               "doesn't validate with computed blinded key: %s",
               tor_cert_describe_signature_status(cert));
      ret = HS_DESC_DECODE_GENERIC_ERROR;
      goto err;
    }
  
    return HS_DESC_DECODE_OK;
   err:
    return ret;
  }
  
  /** Return true iff there are at least one usable intro point in the service
   * descriptor desc. */
  int
  hs_client_any_intro_points_usable(const ed25519_public_key_t *service_pk,
                                    const hs_descriptor_t *desc)
  {
    tor_assert(service_pk);
    tor_assert(desc);
  
    SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
                            const hs_desc_intro_point_t *, ip) {
      if (intro_point_is_usable(service_pk, ip)) {
        goto usable;
      }
    } SMARTLIST_FOREACH_END(ip);
  
    return 0;
   usable:
    return 1;
  }
  
  /** Launch a connection to a hidden service directory to fetch a hidden
   * service descriptor using <b>identity_pk</b> to get the necessary keys.
   *
   * A hs_client_fetch_status_t code is returned. */
  int
  hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
  {
    hs_client_fetch_status_t status;
  
    tor_assert(identity_pk);
  
    if (!can_client_refetch_desc(identity_pk, &status)) {
      return status;
    }
  
    /* Try to fetch the desc and if we encounter an unrecoverable error, mark
     * the desc as unavailable for now. */
    status = fetch_v3_desc(identity_pk);
    if (fetch_status_should_close_socks(status)) {
      close_all_socks_conns_waiting_for_desc(identity_pk, status,
                                             END_STREAM_REASON_RESOLVEFAILED);
      /* Remove HSDir fetch attempts so that we can retry later if the user
       * wants us to regardless of if we closed any connections. */
      purge_hid_serv_request(identity_pk);
    }
    return status;
  }
  
  /** This is called when we are trying to attach an AP connection to these
   * hidden service circuits from connection_ap_handshake_attach_circuit().
   * Return 0 on success, -1 for a transient error that is actions were
   * triggered to recover or -2 for a permenent error where both circuits will
   * marked for close.
   *
   * The following supports every hidden service version. */
  int
  hs_client_send_introduce1(origin_circuit_t *intro_circ,
                            origin_circuit_t *rend_circ)
  {
    return (intro_circ->hs_ident) ? send_introduce1(intro_circ, rend_circ) :
                                    rend_client_send_introduction(intro_circ,
                                                                  rend_circ);
  }
  
  /** Called when the client circuit circ has been established. It can be either
   * an introduction or rendezvous circuit. This function handles all hidden
   * service versions. */
  void
  hs_client_circuit_has_opened(origin_circuit_t *circ)
  {
    tor_assert(circ);
  
    /* Handle both version. v2 uses rend_data and v3 uses the hs circuit
     * identifier hs_ident. Can't be both. */
    switch (TO_CIRCUIT(circ)->purpose) {
    case CIRCUIT_PURPOSE_C_INTRODUCING:
      if (circ->hs_ident) {
        client_intro_circ_has_opened(circ);
      } else {
        rend_client_introcirc_has_opened(circ);
      }
      break;
    case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
      if (circ->hs_ident) {
        client_rendezvous_circ_has_opened(circ);
      } else {
        rend_client_rendcirc_has_opened(circ);
      }
      break;
    default:
      tor_assert_nonfatal_unreached();
    }
  }
  
  /** Called when we receive a RENDEZVOUS_ESTABLISHED cell. Change the state of
   * the circuit to CIRCUIT_PURPOSE_C_REND_READY. Return 0 on success else a
   * negative value and the circuit marked for close. */
  int
  hs_client_receive_rendezvous_acked(origin_circuit_t *circ,
                                     const uint8_t *payload, size_t payload_len)
  {
    tor_assert(circ);
    tor_assert(payload);
  
    (void) payload_len;
  
    if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND) {
      log_warn(LD_PROTOCOL, "Got a RENDEZVOUS_ESTABLISHED but we were not "
                            "expecting one. Closing circuit.");
      goto err;
    }
  
    log_info(LD_REND, "Received an RENDEZVOUS_ESTABLISHED. This circuit is "
                      "now ready for rendezvous.");
    circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_REND_READY);
  
    /* Set timestamp_dirty, because circuit_expire_building expects it to
     * specify when a circuit entered the _C_REND_READY state. */
    TO_CIRCUIT(circ)->timestamp_dirty = time(NULL);
  
    /* From a path bias point of view, this circuit is now successfully used.
     * Waiting any longer opens us up to attacks from malicious hidden services.
     * They could induce the client to attempt to connect to their hidden
     * service and never reply to the client's rend requests */
    pathbias_mark_use_success(circ);
  
    /* If we already have the introduction circuit built, make sure we send
     * the INTRODUCE cell _now_ */
    connection_ap_attach_pending(1);
  
    return 0;
   err:
    circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
    return -1;
  }
  
  void
  client_service_authorization_free_(hs_client_service_authorization_t *auth)
  {
    if (!auth) {
      return;
    }
  
    memwipe(auth, 0, sizeof(*auth));
    tor_free(auth);
  }
  
  /** Helper for digest256map_free. */
  static void
  client_service_authorization_free_void(void *auth)
  {
    client_service_authorization_free_(auth);
  }
  
  static void
  client_service_authorization_free_all(void)
  {
    if (!client_auths) {
      return;
    }
    digest256map_free(client_auths, client_service_authorization_free_void);
  }
  
  /** Check if the auth key file name is valid or not. Return 1 if valid,
   * otherwise return 0. */
  STATIC int
  auth_key_filename_is_valid(const char *filename)
  {
    int ret = 1;
    const char *valid_extension = ".auth_private";
  
    tor_assert(filename);
  
    /* The length of the filename must be greater than the length of the
     * extension and the valid extension must be at the end of filename. */
    if (!strcmpend(filename, valid_extension) &&
        strlen(filename) != strlen(valid_extension)) {
      ret = 1;
    } else {
      ret = 0;
    }
  
    return ret;
  }
  
  /** Parse the client auth credentials off a string in <b>client_key_str</b>
   *  based on the file format documented in the "Client side configuration"
   *  section of rend-spec-v3.txt.
   *
   *  Return NULL if there was an error, otherwise return a newly allocated
   *  hs_client_service_authorization_t structure.
   */
  STATIC hs_client_service_authorization_t *
  parse_auth_file_content(const char *client_key_str)
  {
    char *onion_address = NULL;
    char *auth_type = NULL;
    char *key_type = NULL;
    char *seckey_b32 = NULL;
    hs_client_service_authorization_t *auth = NULL;
    smartlist_t *fields = smartlist_new();
  
    tor_assert(client_key_str);
  
    smartlist_split_string(fields, client_key_str, ":",
                           SPLIT_SKIP_SPACE, 0);
    /* Wrong number of fields. */
    if (smartlist_len(fields) != 4) {
      goto err;
    }
  
    onion_address = smartlist_get(fields, 0);
    auth_type = smartlist_get(fields, 1);
    key_type = smartlist_get(fields, 2);
    seckey_b32 = smartlist_get(fields, 3);
  
    /* Currently, the only supported auth type is "descriptor" and the only
     * supported key type is "x25519". */
    if (strcmp(auth_type, "descriptor") || strcmp(key_type, "x25519")) {
      goto err;
    }
  
    if (strlen(seckey_b32) != BASE32_NOPAD_LEN(CURVE25519_SECKEY_LEN)) {
      log_warn(LD_REND, "Client authorization encoded base32 private key "
                        "length is invalid: %s", seckey_b32);
      goto err;
    }
  
    auth = tor_malloc_zero(sizeof(hs_client_service_authorization_t));
    if (base32_decode((char *) auth->enc_seckey.secret_key,
                      sizeof(auth->enc_seckey.secret_key),
                      seckey_b32, strlen(seckey_b32)) !=
        sizeof(auth->enc_seckey.secret_key)) {
      log_warn(LD_REND, "Client authorization encoded base32 private key "
                        "can't be decoded: %s", seckey_b32);
      goto err;
    }
  
    if (fast_mem_is_zero((const char*)auth->enc_seckey.secret_key,
                         sizeof(auth->enc_seckey.secret_key))) {
      log_warn(LD_REND, "Client authorization private key can't be all-zeroes");
      goto err;
    }
  
    strncpy(auth->onion_address, onion_address, HS_SERVICE_ADDR_LEN_BASE32);
  
    /* We are reading this from the disk, so set the permanent flag anyway. */
    auth->flags |= CLIENT_AUTH_FLAG_IS_PERMANENT;
  
    /* Success. */
    goto done;
  
   err:
    client_service_authorization_free(auth);
   done:
    /* It is also a good idea to wipe the private key. */
    if (seckey_b32) {
      memwipe(seckey_b32, 0, strlen(seckey_b32));
    }
    tor_assert(fields);
    SMARTLIST_FOREACH(fields, char *, s, tor_free(s));
    smartlist_free(fields);
    return auth;
  }
  
  /** From a set of <b>options</b>, setup every client authorization detail
   * found. Return 0 on success or -1 on failure. If <b>validate_only</b>
   * is set, parse, warn and return as normal, but don't actually change
   * the configuration. */
  int
  hs_config_client_authorization(const or_options_t *options,
                                 int validate_only)
  {
    int ret = -1;
    digest256map_t *auths = digest256map_new();
    smartlist_t *file_list = NULL;
  
    tor_assert(options);
  
    /* There is no client auth configured. We can just silently ignore this
     * function. */
    if (!options->ClientOnionAuthDir) {
      ret = 0;
      goto end;
    }
  
    /* Make sure the directory exists and is private enough. */
    if (check_private_dir(options->ClientOnionAuthDir, 0, options->User) < 0) {
      goto end;
    }
  
    file_list = tor_listdir(options->ClientOnionAuthDir);
    if (file_list == NULL) {
      log_warn(LD_REND, "Client authorization key directory %s can't be listed.",
               options->ClientOnionAuthDir);
      goto end;
    }
  
    SMARTLIST_FOREACH_BEGIN(file_list, const char *, filename) {
      hs_client_service_authorization_t *auth = NULL;
      ed25519_public_key_t identity_pk;
  
      auth = get_creds_from_client_auth_filename(filename, options);
      if (!auth) {
        continue;
      }
  
      /* Parse the onion address to get an identity public key and use it
       * as a key of global map in the future. */
      if (hs_parse_address(auth->onion_address, &identity_pk,
                           NULL, NULL) < 0) {
        log_warn(LD_REND, "The onion address \"%s\" is invalid in "
                 "file %s", filename, auth->onion_address);
        client_service_authorization_free(auth);
        continue;
      }
  
      if (digest256map_get(auths, identity_pk.pubkey)) {
          log_warn(LD_REND, "Duplicate authorization for the same hidden "
                   "service address %s.",
                   safe_str_client_opts(options, auth->onion_address));
          client_service_authorization_free(auth);
          goto end;
      }
  
      digest256map_set(auths, identity_pk.pubkey, auth);
      log_info(LD_REND, "Loaded a client authorization key file %s.",
               filename);
    } SMARTLIST_FOREACH_END(filename);
  
    /* Success. */
    ret = 0;
  
   end:
    if (file_list) {
      SMARTLIST_FOREACH(file_list, char *, s, tor_free(s));
      smartlist_free(file_list);
    }
  
    if (!validate_only && ret == 0) {
      client_service_authorization_free_all();
      client_auths = auths;
    } else {
      digest256map_free(auths, client_service_authorization_free_void);
    }
  
    return ret;
  }
  
  /** Called when a descriptor directory fetch is done.
   *
   * Act accordingly on all entry connections depending on the HTTP status code
   * we got. In case of an error, the SOCKS error is set (if ExtendedErrors is
   * set).
   *
   * The reason is a human readable string returned by the directory server
   * which can describe the status of the request. The body is the response
   * content, on 200 code it is the descriptor itself. Finally, the status_code
   * is the HTTP code returned by the directory server. */
  void
  hs_client_dir_fetch_done(dir_connection_t *dir_conn, const char *reason,
                           const char *body, const int status_code)
  {
    smartlist_t *entry_conns;
  
    tor_assert(dir_conn);
    tor_assert(body);
  
    /* Get all related entry connections. */
    entry_conns = find_entry_conns(&dir_conn->hs_ident->identity_pk);
  
    switch (status_code) {
    case 200:
      client_dir_fetch_200(dir_conn, entry_conns, body);
      break;
    case 404:
      client_dir_fetch_404(dir_conn, entry_conns);
      break;
    case 400:
      client_dir_fetch_400(dir_conn, reason);
      break;
    default:
      client_dir_fetch_unexpected(dir_conn, reason, status_code);
      break;
    }
  
    /* We don't have ownership of the objects in this list. */
    smartlist_free(entry_conns);
  }
  
  /** Return a newly allocated extend_info_t for a randomly chosen introduction
   * point for the given edge connection identifier ident. Return NULL if we
   * can't pick any usable introduction points. */
  extend_info_t *
  hs_client_get_random_intro_from_edge(const edge_connection_t *edge_conn)
  {
    tor_assert(edge_conn);
  
    return (edge_conn->hs_ident) ?
      client_get_random_intro(&edge_conn->hs_ident->identity_pk) :
      rend_client_get_random_intro(edge_conn->rend_data);
  }
  
  /** Called when get an INTRODUCE_ACK cell on the introduction circuit circ.
   * Return 0 on success else a negative value is returned. The circuit will be
   * closed or reuse to extend again to another intro point. */
  int
  hs_client_receive_introduce_ack(origin_circuit_t *circ,
                                  const uint8_t *payload, size_t payload_len)
  {
    int ret = -1;
  
    tor_assert(circ);
    tor_assert(payload);
  
    if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) {
      log_warn(LD_PROTOCOL, "Unexpected INTRODUCE_ACK on circuit %u.",
               (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
      circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
      goto end;
    }
  
    ret = (circ->hs_ident) ? handle_introduce_ack(circ, payload, payload_len) :
                             rend_client_introduction_acked(circ, payload,
                                                            payload_len);
    /* For path bias: This circuit was used successfully. NACK or ACK counts. */
    pathbias_mark_use_success(circ);
  
   end:
    return ret;
  }
  
  /** Called when get a RENDEZVOUS2 cell on the rendezvous circuit circ.  Return
   * 0 on success else a negative value is returned. The circuit will be closed
   * on error. */
  int
  hs_client_receive_rendezvous2(origin_circuit_t *circ,
                                const uint8_t *payload, size_t payload_len)
  {
    int ret = -1;
  
    tor_assert(circ);
    tor_assert(payload);
  
    /* Circuit can possibly be in both state because we could receive a
     * RENDEZVOUS2 cell before the INTRODUCE_ACK has been received. */
    if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY &&
        TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) {
      log_warn(LD_PROTOCOL, "Unexpected RENDEZVOUS2 cell on circuit %u. "
                            "Closing circuit.",
               (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
      circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
      goto end;
    }
  
    log_info(LD_REND, "Got RENDEZVOUS2 cell from hidden service on circuit %u.",
             TO_CIRCUIT(circ)->n_circ_id);
  
    ret = (circ->hs_ident) ? handle_rendezvous2(circ, payload, payload_len) :
                             rend_client_receive_rendezvous(circ, payload,
                                                            payload_len);
   end:
    return ret;
  }
  
  /** Extend the introduction circuit circ to another valid introduction point
   * for the hidden service it is trying to connect to, or mark it and launch a
   * new circuit if we can't extend it.  Return 0 on success or possible
   * success. Return -1 and mark the introduction circuit for close on permanent
   * failure.
   *
   * On failure, the caller is responsible for marking the associated rendezvous
   * circuit for close. */
  int
  hs_client_reextend_intro_circuit(origin_circuit_t *circ)
  {
    int ret = -1;
    extend_info_t *ei;
  
    tor_assert(circ);
  
    ei = (circ->hs_ident) ?
      client_get_random_intro(&circ->hs_ident->identity_pk) :
      rend_client_get_random_intro(circ->rend_data);
    if (ei == NULL) {
      log_warn(LD_REND, "No usable introduction points left. Closing.");
      circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
      goto end;
    }
  
    if (circ->remaining_relay_early_cells) {
      log_info(LD_REND, "Re-extending circ %u, this time to %s.",
               (unsigned int) TO_CIRCUIT(circ)->n_circ_id,
               safe_str_client(extend_info_describe(ei)));
      ret = circuit_extend_to_new_exit(circ, ei);
      if (ret == 0) {
        /* We were able to extend so update the timestamp so we avoid expiring
         * this circuit too early. The intro circuit is short live so the
         * linkability issue is minimized, we just need the circuit to hold a
         * bit longer so we can introduce. */
        TO_CIRCUIT(circ)->timestamp_dirty = time(NULL);
      }
    } else {
      log_info(LD_REND, "Closing intro circ %u (out of RELAY_EARLY cells).",
               (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
      circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
      /* connection_ap_handshake_attach_circuit will launch a new intro circ. */
      ret = 0;
    }
  
   end:
    extend_info_free(ei);
    return ret;
  }
  
  /** Close all client introduction circuits related to the given descriptor.
   * This is called with a descriptor that is about to get replaced in the
   * client cache.
   *
   * Even though the introduction point might be exactly the same, we'll rebuild
   * them if needed but the odds are very low that an existing matching
   * introduction circuit exists at that stage. */
  void
  hs_client_close_intro_circuits_from_desc(const hs_descriptor_t *desc)
  {
    origin_circuit_t *ocirc = NULL;
  
    tor_assert(desc);
  
    /* We iterate over all client intro circuits because they aren't kept in the
     * HS circuitmap. That is probably something we want to do one day. */
    while ((ocirc = circuit_get_next_intro_circ(ocirc, true))) {
      if (ocirc->hs_ident == NULL) {
        /* Not a v3 circuit, ignore it. */
        continue;
      }
  
      /* Does it match any IP in the given descriptor? If not, ignore. */
      if (find_desc_intro_point_by_ident(ocirc->hs_ident, desc) == NULL) {
        continue;
      }
  
      /* We have a match. Close the circuit as consider it expired. */
      circuit_mark_for_close(TO_CIRCUIT(ocirc), END_CIRC_REASON_FINISHED);
    }
  }
  
  /** Release all the storage held by the client subsystem. */
  void
  hs_client_free_all(void)
  {
    /* Purge the hidden service request cache. */
    hs_purge_last_hid_serv_requests();
    client_service_authorization_free_all();
  }
  
  /** Purge all potentially remotely-detectable state held in the hidden
   * service client code. Called on SIGNAL NEWNYM. */
  void
  hs_client_purge_state(void)
  {
    /* v2 subsystem. */
    rend_client_purge_state();
  
    /* Cancel all descriptor fetches. Do this first so once done we are sure
     * that our descriptor cache won't modified. */
    cancel_descriptor_fetches();
    /* Purge the introduction point state cache. */
    hs_cache_client_intro_state_purge();
    /* Purge the descriptor cache. */
    hs_cache_purge_as_client();
    /* Purge the last hidden service request cache. */
    hs_purge_last_hid_serv_requests();
    /* Purge ephemeral client authorization. */
    purge_ephemeral_client_auth();
  
    log_info(LD_REND, "Hidden service client state has been purged.");
  }
  
  /** Called when our directory information has changed. */
  void
  hs_client_dir_info_changed(void)
  {
    /* We have possibly reached the minimum directory information or new
     * consensus so retry all pending SOCKS connection in
     * AP_CONN_STATE_RENDDESC_WAIT state in order to fetch the descriptor. */
    retry_all_socks_conn_waiting_for_desc();
  }
  
  #ifdef TOR_UNIT_TESTS
  
  STATIC void
  set_hs_client_auths_map(digest256map_t *map)
  {
    client_auths = map;
  }
  
  #endif /* defined(TOR_UNIT_TESTS) */
  