text:
/* 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/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 identity_pk
 * because of status. Find all pending SOCKS connections for this
 * service that are waiting on the descriptor and close them with
 * reason. */
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 hs_conn_ident 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 onion_identity_pk, fetch its
 * descriptor by launching a dir connection to hsdir. 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 onion_identity_pk. */
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 onion_identity_pk.
 *
 * 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 onion_identity_pk, fetch its descriptor. If
 * hsdirs 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. */
static void
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. */
    circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
    goto end;
  }

  /* 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) {
    /* 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);
    goto end;
  }

  /* Reaching this point means we didn't find any intro point for this circuit
   * which is not supposed to happen. */
  tor_assert_nonfatal_unreached();

 end:
  return;
}

/** 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. */
  setup_intro_circ_auth_key(circ);

  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) {
      if (BUG(!node_supports_v3_rendezvous_point(rp_node))) {
        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;
}

/** 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 (BUG(desc == NULL)) {
    /* We can't continue without a descriptor. */
    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.");
      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:%d'. Retrying at another directory.",
           status_code, escaped(reason), TO_CONN(dir_conn)->address,
           TO_CONN(dir_conn)->port);
  /* 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 onion_address. The base directory is dir.
 *  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 creds 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 creds as part of the client auth subsystem.
 *
 * Takes ownership of creds.
 **/
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 filename 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 filename 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 cred 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 hs_address. */
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 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
 *  conn 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;
  uint8_t subcredential[DIGEST256_LEN];
  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 identity_pk 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 client_key_str
 *  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 options, setup every client authorization detail
 * found. Return 0 on success or -1 on failure. If validate_only
 * 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) */


text:
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GPU_COMMAND_BUFFER_SERVICE_COMMAND_EXECUTOR_H_
#define GPU_COMMAND_BUFFER_SERVICE_COMMAND_EXECUTOR_H_

#include <stdint.h>

#include <queue>

#include "base/atomic_ref_count.h"
#include "base/atomicops.h"
#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/linked_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/shared_memory.h"
#include "base/memory/weak_ptr.h"
#include "gpu/command_buffer/service/cmd_buffer_engine.h"
#include "gpu/command_buffer/service/cmd_parser.h"
#include "gpu/command_buffer/service/command_buffer_service.h"
#include "gpu/command_buffer/service/gles2_cmd_decoder.h"
#include "gpu/gpu_export.h"

namespace gpu {

class PreemptionFlag : public base::RefCountedThreadSafe<PreemptionFlag> {
 public:
  PreemptionFlag() : flag_(0) {}

  bool IsSet() { return !base::AtomicRefCountIsZero(&flag_); }
  void Set() { base::AtomicRefCountInc(&flag_); }
  void Reset() { base::subtle::NoBarrier_Store(&flag_, 0); }

 private:
  base::AtomicRefCount flag_;

  ~PreemptionFlag() {}

  friend class base::RefCountedThreadSafe<PreemptionFlag>;
};

// This class schedules commands that have been flushed. They are received via
// a command buffer and forwarded to a command parser. TODO(apatrick): This
// class should not know about the decoder. Do not add additional dependencies
// on it.
class GPU_EXPORT CommandExecutor
    : NON_EXPORTED_BASE(public CommandBufferEngine),
      public base::SupportsWeakPtr<CommandExecutor> {
 public:
  CommandExecutor(CommandBufferServiceBase* command_buffer,
                  AsyncAPIInterface* handler,
                  gles2::GLES2Decoder* decoder);

  ~CommandExecutor() override;

  void PutChanged();

  void SetPreemptByFlag(scoped_refptr<PreemptionFlag> flag) {
    preemption_flag_ = flag;
  }

  // Sets whether commands should be processed by this scheduler. Setting to
  // false unschedules. Setting to true reschedules.
  void SetScheduled(bool scheduled);

  bool scheduled() const { return scheduled_; }

  // Returns whether the scheduler needs to be polled again in the future to
  // process pending queries.
  bool HasPendingQueries() const;

  // Process pending queries and return. HasPendingQueries() can be used to
  // determine if there's more pending queries after this has been called.
  void ProcessPendingQueries();

  typedef base::Callback<void(bool /* scheduled */)> SchedulingChangedCallback;

  // Sets a callback that is invoked just before scheduler is rescheduled
  // or descheduled. Takes ownership of callback object.
  void SetSchedulingChangedCallback(const SchedulingChangedCallback& callback);

  // Implementation of CommandBufferEngine.
  scoped_refptr<Buffer> GetSharedMemoryBuffer(int32_t shm_id) override;
  void set_token(int32_t token) override;
  bool SetGetBuffer(int32_t transfer_buffer_id) override;
  bool SetGetOffset(int32_t offset) override;
  int32_t GetGetOffset() override;

  void SetCommandProcessedCallback(const base::Closure& callback);

  // Returns whether the scheduler needs to be polled again in the future to
  // process idle work.
  bool HasMoreIdleWork() const;

  // Perform some idle work and return. HasMoreIdleWork() can be used to
  // determine if there's more idle work do be done after this has been called.
  void PerformIdleWork();

  CommandParser* parser() const { return parser_.get(); }

 private:
  bool IsPreempted();

  // The CommandExecutor holds a weak reference to the CommandBuffer. The
  // CommandBuffer owns the CommandExecutor and holds a strong reference to it
  // through the ProcessCommands callback.
  CommandBufferServiceBase* command_buffer_;

  // The parser uses this to execute commands.
  AsyncAPIInterface* handler_;

  // Does not own decoder. TODO(apatrick): The CommandExecutor shouldn't need a
  // pointer to the decoder, it is only used to initialize the CommandParser,
  // which could be an argument to the constructor, and to determine the
  // reason for context lost.
  gles2::GLES2Decoder* decoder_;

  // TODO(apatrick): The CommandExecutor currently creates and owns the parser.
  // This should be an argument to the constructor.
  scoped_ptr<CommandParser> parser_;

  // Whether the scheduler is currently able to process more commands.
  bool scheduled_;

  SchedulingChangedCallback scheduling_changed_callback_;
  base::Closure descheduled_callback_;
  base::Closure command_processed_callback_;

  // If non-NULL and |preemption_flag_->IsSet()|, exit PutChanged early.
  scoped_refptr<PreemptionFlag> preemption_flag_;
  bool was_preempted_;

  DISALLOW_COPY_AND_ASSIGN(CommandExecutor);
};

}  // namespace gpu

#endif  // GPU_COMMAND_BUFFER_SERVICE_COMMAND_EXECUTOR_H_

redpajama_set_name: RedPajamaGithub


text:
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Run-time GCD & LCM Determination

      Header:  <boost/math/common_factor_rt.hpp>

template < typename IntegerType >
IntegerType  boost::math::gcd( IntegerType const &a, IntegerType const &b );

template < typename IntegerType >
IntegerType  boost::math::lcm( IntegerType const &a, IntegerType const &b );

      The boost::math::gcd function template returns the greatest common (nonnegative)
      divisor of the two integers passed to it. The boost::math::lcm function template
      returns the least common (nonnegative) multiple of the two integers passed
      to it. The function templates are parameterized on the function arguments'
      IntegerType, which is also the return type. Internally, these function templates
      use an object of the corresponding version of the gcd_evaluator and lcm_evaluator
      class templates, respectively.

Copyright © 2006-2010, 2012-2014 Nikhar Agrawal,
      Anton Bikineev, Paul A. Bristow, Marco Guazzone, Christopher Kormanyos, Hubert
      Holin, Bruno Lalande, John Maddock, Johan Råde, Gautam Sewani, Benjamin Sobotta,
      Thijs van den Berg, Daryle Walker and Xiaogang Zhang

        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)


text:
package com.ververica.flinktraining.exercises.datastream_scala.process

import com.ververica.flinktraining.exercises.datastream_java.datatypes.TaxiRide
import com.ververica.flinktraining.exercises.datastream_java.sources.TaxiRideSource
import com.ververica.flinktraining.exercises.datastream_java.utils.ExerciseBase._
import com.ververica.flinktraining.exercises.datastream_java.utils.{ExerciseBase, MissingSolutionException}
import org.apache.flink.api.java.utils.ParameterTool
import org.apache.flink.configuration.Configuration
import org.apache.flink.streaming.api.TimeCharacteristic
import org.apache.flink.streaming.api.functions.KeyedProcessFunction
import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment
import org.apache.flink.streaming.api.scala._
import org.apache.flink.util.Collector

/**
  * The "Long Ride Alerts" exercise of the Flink training
  * (http://training.ververica.com).
  *
  * The goal for this exercise is to emit START events for taxi rides that have not been matched
  * by an END event during the first 2 hours of the ride.
  *
  * Parameters:
  * -input path-to-input-file
  *
  */
object LongRidesExercise {
  def main(args: Array[String]) {

    // parse parameters
    val params = ParameterTool.fromArgs(args)
    val input = params.get("input", ExerciseBase.pathToRideData)

    val maxDelay = 60     // events are out of order by max 60 seconds
    val speed = 1800      // events of 30 minutes are served every second

    // set up the execution environment
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)
    env.setParallelism(ExerciseBase.parallelism)

    val rides = env.addSource(rideSourceOrTest(new TaxiRideSource(input, maxDelay, speed)))

    val longRides = rides
      .keyBy(_.rideId)
      .process(new ImplementMeFunction())

    printOrTest(longRides)

    env.execute("Long Taxi Rides")
  }

  class ImplementMeFunction extends KeyedProcessFunction[Long, TaxiRide, TaxiRide] {

    override def open(parameters: Configuration): Unit = {
      throw new MissingSolutionException()
    }

    override def processElement(ride: TaxiRide,
                                context: KeyedProcessFunction[Long, TaxiRide, TaxiRide]#Context,
                                out: Collector[TaxiRide]): Unit = {
    }

    override def onTimer(timestamp: Long,
                         ctx: KeyedProcessFunction[Long, TaxiRide, TaxiRide]#OnTimerContext,
                         out: Collector[TaxiRide]): Unit = {
    }

  }

}


text:
import { isNaN } from "lodash";
export = isNaN;


text:
<?php
    require_once __DIR__ . "/../class/autoload.php";

    use \html\Page as Page;
    use \html\AdministratorMenu as AdministratorMenu;
    use \html\Forms as Forms;
    use \configuration\Globals as Globals;
    use \utilities\Session as Session;

    $session = new Session();
    $session->verifyIfSessionIsStarted();

    Page::startHeader("Editar Página");
    Page::styleSheet("user");
    Page::styleSheet("form");
    echo "";
    Page::closeHeader();

    $menu = new AdministratorMenu();
    $menu->construct();
?>

Edição de Página

      <form action="<?php echo PROJECT_ROOT;?>controller/updatePage.php" method="POST" enctype="multipart/form-data">
        <fieldset>
            <?php Forms::updatePageForm($_GET['pages']); ?>
        </fieldset>
        <input type="hidden" value="<?php echo $_GET['pages']?>" id="page_code">
        <input type="submit" value="Atualizar">
      </form>

<?php
    Page::footer();
    Page::closeBody();
?>