circuitlist.c

关于tor匿名通信的源代码

    memlen = sizeof(or_circuit_t);
    tor_assert(circ->magic == OR_CIRCUIT_MAGIC);

    if (ocirc->p_crypto)
      crypto_free_cipher_env(ocirc->p_crypto);
    if (ocirc->p_digest)
      crypto_free_digest_env(ocirc->p_digest);
    if (ocirc->n_crypto)
      crypto_free_cipher_env(ocirc->n_crypto);
    if (ocirc->n_digest)
      crypto_free_digest_env(ocirc->n_digest);

    if (ocirc->rend_splice) {
      or_circuit_t *other = ocirc->rend_splice;
      tor_assert(other->_base.magic == OR_CIRCUIT_MAGIC);
      other->rend_splice = NULL;
    }

    /* remove from map. */
    circuit_set_p_circid_orconn(ocirc, 0, NULL);

    /* Clear cell queue _after_ removing it from the map.  Otherwise our
     * "active" checks will be violated. */
    cell_queue_clear(&ocirc->p_conn_cells);
  }

  tor_free(circ->n_conn_onionskin);

  /* Remove from map. */
  circuit_set_n_circid_orconn(circ, 0, NULL);

  /* Clear cell queue _after_ removing it from the map.  Otherwise our
   * "active" checks will be violated. */
  cell_queue_clear(&circ->n_conn_cells);

  memset(circ, 0xAA, memlen); /* poison memory */
  tor_free(mem);
}

/** Deallocate space associated with the linked list <b>cpath</b>. */
static void
circuit_free_cpath(crypt_path_t *cpath)
{
  crypt_path_t *victim, *head=cpath;

  if (!cpath)
    return;

  /* it's a doubly linked list, so we have to notice when we've
   * gone through it once. */
  while (cpath->next && cpath->next != head) {
    victim = cpath;
    cpath = victim->next;
    circuit_free_cpath_node(victim);
  }

  circuit_free_cpath_node(cpath);
}

/** Release all storage held by circuits. */
void
circuit_free_all(void)
{
  circuit_t *next;
  while (global_circuitlist) {
    next = global_circuitlist->next;
    if (! CIRCUIT_IS_ORIGIN(global_circuitlist)) {
      or_circuit_t *or_circ = TO_OR_CIRCUIT(global_circuitlist);
      while (or_circ->resolving_streams) {
        edge_connection_t *next_conn;
        next_conn = or_circ->resolving_streams->next_stream;
        connection_free(TO_CONN(or_circ->resolving_streams));
        or_circ->resolving_streams = next_conn;
      }
    }
    circuit_free(global_circuitlist);
    global_circuitlist = next;
  }
  if (circuits_pending_or_conns) {
    smartlist_free(circuits_pending_or_conns);
    circuits_pending_or_conns = NULL;
  }
  HT_CLEAR(orconn_circid_map, &orconn_circid_circuit_map);
}

/** Deallocate space associated with the cpath node <b>victim</b>. */
static void
circuit_free_cpath_node(crypt_path_t *victim)
{
  if (victim->f_crypto)
    crypto_free_cipher_env(victim->f_crypto);
  if (victim->b_crypto)
    crypto_free_cipher_env(victim->b_crypto);
  if (victim->f_digest)
    crypto_free_digest_env(victim->f_digest);
  if (victim->b_digest)
    crypto_free_digest_env(victim->b_digest);
  if (victim->dh_handshake_state)
    crypto_dh_free(victim->dh_handshake_state);
  if (victim->extend_info)
    extend_info_free(victim->extend_info);

  memset(victim, 0xBB, sizeof(crypt_path_t)); /* poison memory */
  tor_free(victim);
}

/** A helper function for circuit_dump_by_conn() below. Log a bunch
 * of information about circuit <b>circ</b>.
 */
static void
circuit_dump_details(int severity, circuit_t *circ, int conn_array_index,
                     const char *type, int this_circid, int other_circid)
{
  log(severity, LD_CIRC, "Conn %d has %s circuit: circID %d (other side %d), "
      "state %d (%s), born %d:",
      conn_array_index, type, this_circid, other_circid, circ->state,
      circuit_state_to_string(circ->state), (int)circ->timestamp_created);
  if (CIRCUIT_IS_ORIGIN(circ)) { /* circ starts at this node */
    circuit_log_path(severity, LD_CIRC, TO_ORIGIN_CIRCUIT(circ));
  }
}

/** Log, at severity <b>severity</b>, information about each circuit
 * that is connected to <b>conn</b>.
 */
void
circuit_dump_by_conn(connection_t *conn, int severity)
{
  circuit_t *circ;
  edge_connection_t *tmpconn;

  for (circ=global_circuitlist;circ;circ = circ->next) {
    circid_t n_circ_id = circ->n_circ_id, p_circ_id = 0;
    if (circ->marked_for_close)
      continue;

    if (! CIRCUIT_IS_ORIGIN(circ))
      p_circ_id = TO_OR_CIRCUIT(circ)->p_circ_id;

    if (! CIRCUIT_IS_ORIGIN(circ) && TO_OR_CIRCUIT(circ)->p_conn &&
        TO_CONN(TO_OR_CIRCUIT(circ)->p_conn) == conn)
      circuit_dump_details(severity, circ, conn->conn_array_index, "App-ward",
                           p_circ_id, n_circ_id);
    if (CIRCUIT_IS_ORIGIN(circ)) {
      for (tmpconn=TO_ORIGIN_CIRCUIT(circ)->p_streams; tmpconn;
           tmpconn=tmpconn->next_stream) {
        if (TO_CONN(tmpconn) == conn) {
          circuit_dump_details(severity, circ, conn->conn_array_index,
                               "App-ward", p_circ_id, n_circ_id);
        }
      }
    }
    if (circ->n_conn && TO_CONN(circ->n_conn) == conn)
      circuit_dump_details(severity, circ, conn->conn_array_index, "Exit-ward",
                           n_circ_id, p_circ_id);
    if (! CIRCUIT_IS_ORIGIN(circ)) {
      for (tmpconn=TO_OR_CIRCUIT(circ)->n_streams; tmpconn;
           tmpconn=tmpconn->next_stream) {
        if (TO_CONN(tmpconn) == conn) {
          circuit_dump_details(severity, circ, conn->conn_array_index,
                               "Exit-ward", n_circ_id, p_circ_id);
        }
      }
    }
    if (!circ->n_conn && circ->n_addr && circ->n_port &&
        circ->n_addr == conn->addr &&
        circ->n_port == conn->port &&
        conn->type == CONN_TYPE_OR &&
        !memcmp(TO_OR_CONN(conn)->identity_digest, circ->n_conn_id_digest,
                DIGEST_LEN)) {
      circuit_dump_details(severity, circ, conn->conn_array_index,
                           (circ->state == CIRCUIT_STATE_OPEN &&
                            !CIRCUIT_IS_ORIGIN(circ)) ?
                             "Endpoint" : "Pending",
                           n_circ_id, p_circ_id);
    }
  }
}

/** Return the circuit whose global ID is <b>id</b>, or NULL if no
 * such circuit exists. */
origin_circuit_t *
circuit_get_by_global_id(uint32_t id)
{
  circuit_t *circ;
  for (circ=global_circuitlist;circ;circ = circ->next) {
    if (CIRCUIT_IS_ORIGIN(circ) &&
        TO_ORIGIN_CIRCUIT(circ)->global_identifier == id) {
      if (circ->marked_for_close)
        return NULL;
      else
        return TO_ORIGIN_CIRCUIT(circ);
    }
  }
  return NULL;
}

/** Return a circ such that:
 *  - circ-\>n_circ_id or circ-\>p_circ_id is equal to <b>circ_id</b>, and
 *  - circ is attached to <b>conn</b>, either as p_conn or n_conn.
 * Return NULL if no such circuit exists.
 */
static INLINE circuit_t *
circuit_get_by_circid_orconn_impl(uint16_t circ_id, or_connection_t *conn)
{
  orconn_circid_circuit_map_t search;
  orconn_circid_circuit_map_t *found;

  if (_last_circid_orconn_ent &&
      circ_id == _last_circid_orconn_ent->circ_id &&
      conn == _last_circid_orconn_ent->or_conn) {
    found = _last_circid_orconn_ent;
  } else {
    search.circ_id = circ_id;
    search.or_conn = conn;
    found = HT_FIND(orconn_circid_map, &orconn_circid_circuit_map, &search);
    _last_circid_orconn_ent = found;
  }
  if (found && found->circuit)
    return found->circuit;

  return NULL;

  /* The rest of this checks for bugs. Disabled by default. */
  {
    circuit_t *circ;
    for (circ=global_circuitlist;circ;circ = circ->next) {
      if (! CIRCUIT_IS_ORIGIN(circ)) {
        or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
        if (or_circ->p_conn == conn && or_circ->p_circ_id == circ_id) {
          log_warn(LD_BUG,
                   "circuit matches p_conn, but not in hash table (Bug!)");
          return circ;
        }
      }
      if (circ->n_conn == conn && circ->n_circ_id == circ_id) {
        log_warn(LD_BUG,
                 "circuit matches n_conn, but not in hash table (Bug!)");
        return circ;
      }
    }
    return NULL;
  }
}

/** Return a circ such that:
 *  - circ-\>n_circ_id or circ-\>p_circ_id is equal to <b>circ_id</b>, and
 *  - circ is attached to <b>conn</b>, either as p_conn or n_conn.
 *  - circ is not marked for close.
 * Return NULL if no such circuit exists.
 */
circuit_t *
circuit_get_by_circid_orconn(uint16_t circ_id, or_connection_t *conn)
{
  circuit_t *circ = circuit_get_by_circid_orconn_impl(circ_id, conn);
  if (!circ || circ->marked_for_close)
    return NULL;
  else
    return circ;
}

/** Return the circuit that a given edge connection is using. */
circuit_t *
circuit_get_by_edge_conn(edge_connection_t *conn)
{
  circuit_t *circ;

  circ = conn->on_circuit;
  tor_assert(!circ ||
             (CIRCUIT_IS_ORIGIN(circ) ? circ->magic == ORIGIN_CIRCUIT_MAGIC
                                      : circ->magic == OR_CIRCUIT_MAGIC));

  return circ;
}

/** For each circuit that has <b>conn</b> as n_conn or p_conn, unlink the
 * circuit from the orconn,circid map, and mark it for close if it hasn't
 * been marked already.
 */
void
circuit_unlink_all_from_or_conn(or_connection_t *conn, int reason)
{
  circuit_t *circ;

  connection_or_unlink_all_active_circs(conn);

  for (circ = global_circuitlist; circ; circ = circ->next) {
    int mark = 0;
    if (circ->n_conn == conn) {
        circuit_set_n_circid_orconn(circ, 0, NULL);
        mark = 1;
    }
    if (! CIRCUIT_IS_ORIGIN(circ)) {
      or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
      if (or_circ->p_conn == conn) {
        circuit_set_p_circid_orconn(or_circ, 0, NULL);
        mark = 1;
      }
    }
    if (mark && !circ->marked_for_close)
      circuit_mark_for_close(circ, reason);
  }
}

/** Return a circ such that:
 *  - circ-\>rend_query is equal to <b>rend_query</b>, and
 *  - circ-\>purpose is equal to <b>purpose</b>.
 *
 * Return NULL if no such circuit exists.
 */
origin_circuit_t *
circuit_get_by_rend_query_and_purpose(const char *rend_query, uint8_t purpose)
{
  circuit_t *circ;

  tor_assert(CIRCUIT_PURPOSE_IS_ORIGIN(purpose));

  for (circ = global_circuitlist; circ; circ = circ->next) {
    if (!circ->marked_for_close &&
        circ->purpose == purpose &&
        !rend_cmp_service_ids(rend_query, TO_ORIGIN_CIRCUIT(circ)->rend_query))
      return TO_ORIGIN_CIRCUIT(circ);
  }
  return NULL;
}

/** Return the first circuit originating here in global_circuitlist after
 * <b>start</b> whose purpose is <b>purpose</b>, and where
 * <b>digest</b> (if set) matches the rend_pk_digest field. Return NULL if no
 * circuit is found.  If <b>start</b> is NULL, begin at the start of the list.
 */
origin_circuit_t *
circuit_get_next_by_pk_and_purpose(origin_circuit_t *start,
                                   const char *digest, uint8_t purpose)
{
  circuit_t *circ;
  tor_assert(CIRCUIT_PURPOSE_IS_ORIGIN(purpose));
  if (start == NULL)
    circ = global_circuitlist;
  else
    circ = TO_CIRCUIT(start)->next;

  for ( ; circ; circ = circ->next) {
    if (circ->marked_for_close)
      continue;
    if (circ->purpose != purpose)
      continue;
    if (!digest)
      return TO_ORIGIN_CIRCUIT(circ);
    else if (!memcmp(TO_ORIGIN_CIRCUIT(circ)->rend_pk_digest,
                     digest, DIGEST_LEN))
      return TO_ORIGIN_CIRCUIT(circ);
  }
  return NULL;
}

/** Return the first OR circuit in the global list whose purpose is
 * <b>purpose</b>, and whose rend_token is the <b>len</b>-byte
 * <b>token</b>. */
static or_circuit_t *
circuit_get_by_rend_token_and_purpose(uint8_t purpose, const char *token,
                                      size_t len)
{
  circuit_t *circ;
  for (circ = global_circuitlist; circ; circ = circ->next) {
    if (! circ->marked_for_close &&
        circ->purpose == purpose &&
        ! memcmp(TO_OR_CIRCUIT(circ)->rend_token, token, len))
      return TO_OR_CIRCUIT(circ);
  }
  return NULL;
}

/** Return the circuit waiting for a rendezvous with the provided cookie.
 * Return NULL if no such circuit is found.
 */
or_circuit_t *
circuit_get_rendezvous(const char *cookie)
{
  return circuit_get_by_rend_token_and_purpose(
                                     CIRCUIT_PURPOSE_REND_POINT_WAITING,
                                     cookie, REND_COOKIE_LEN);
}

/** Return the circuit waiting for intro cells of the given digest.
 * Return NULL if no such circuit is found.
 */
or_circuit_t *
circuit_get_intro_point(const char *digest)
{
  return circuit_get_by_rend_token_and_purpose(
                                     CIRCUIT_PURPOSE_INTRO_POINT, digest,
                                     DIGEST_LEN);
}

/** Return a circuit that is open, is CIRCUIT_PURPOSE_C_GENERAL,
 * has a timestamp_dirty value of 0, has flags matching the CIRCLAUNCH_*
 * flags in <b>flags</b>, and if info is defined, does not already use info
 * as any of its hops; or NULL if no circuit fits this description.
 *
 * If !CIRCLAUNCH_NEED_UPTIME, prefer returning non-uptime circuits.
 */