connection.c

关于tor匿名通信的源代码

  }

  if (conn->type == CONN_TYPE_OR &&
      !tor_digest_is_zero(TO_OR_CONN(conn)->identity_digest)) {
    log_warn(LD_BUG, "called on OR conn with non-zeroed identity_digest");
    connection_or_remove_from_identity_map(TO_OR_CONN(conn));
  }

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

/** Make sure <b>conn</b> isn't in any of the global conn lists; then free it.
 */
void
connection_free(connection_t *conn)
{
  tor_assert(conn);
  tor_assert(!connection_is_on_closeable_list(conn));
  tor_assert(!connection_in_array(conn));
  if (conn->linked_conn) {
    log_err(LD_BUG, "Called with conn->linked_conn still set.");
    tor_fragile_assert();
    conn->linked_conn->linked_conn = NULL;
    if (! conn->linked_conn->marked_for_close &&
        conn->linked_conn->reading_from_linked_conn)
      connection_start_reading(conn->linked_conn);
    conn->linked_conn = NULL;
  }
  if (connection_speaks_cells(conn)) {
    if (!tor_digest_is_zero(TO_OR_CONN(conn)->identity_digest)) {
      connection_or_remove_from_identity_map(TO_OR_CONN(conn));
    }
  }
  if (conn->type == CONN_TYPE_CONTROL) {
    TO_CONTROL_CONN(conn)->event_mask = 0;
    control_update_global_event_mask();
  }
  connection_unregister_events(conn);
  _connection_free(conn);
}

/** Call _connection_free() on every connection in our array, and release all
 * storage helpd by connection.c. This is used by cpuworkers and dnsworkers
 * when they fork, so they don't keep resources held open (especially
 * sockets).
 *
 * Don't do the checks in connection_free(), because they will
 * fail.
 */
void
connection_free_all(void)
{
  smartlist_t *conns = get_connection_array();

  /* We don't want to log any messages to controllers. */
  SMARTLIST_FOREACH(conns, connection_t *, conn,
    if (conn->type == CONN_TYPE_CONTROL)
      TO_CONTROL_CONN(conn)->event_mask = 0);

  control_update_global_event_mask();

  /* Unlink everything from the identity map. */
  connection_or_clear_identity_map();

  SMARTLIST_FOREACH(conns, connection_t *, conn, _connection_free(conn));

  if (outgoing_addrs) {
    SMARTLIST_FOREACH(outgoing_addrs, void*, addr, tor_free(addr));
    smartlist_free(outgoing_addrs);
    outgoing_addrs = NULL;
  }
}

/** Do any cleanup needed:
 *   - Directory conns that failed to fetch a rendezvous descriptor
 *     need to inform pending rendezvous streams.
 *   - OR conns need to call rep_hist_note_*() to record status.
 *   - AP conns need to send a socks reject if necessary.
 *   - Exit conns need to call connection_dns_remove() if necessary.
 *   - AP and Exit conns need to send an end cell if they can.
 *   - DNS conns need to fail any resolves that are pending on them.
 *   - OR and edge connections need to be unlinked from circuits.
 */
void
connection_about_to_close_connection(connection_t *conn)
{
  circuit_t *circ;
  dir_connection_t *dir_conn;
  or_connection_t *or_conn;
  edge_connection_t *edge_conn;
  time_t now = time(NULL);

  tor_assert(conn->marked_for_close);

  if (CONN_IS_EDGE(conn)) {
    if (!conn->edge_has_sent_end) {
      log_warn(LD_BUG, "(Harmless.) Edge connection (marked at %s:%d) "
               "hasn't sent end yet?",
               conn->marked_for_close_file, conn->marked_for_close);
      tor_fragile_assert();
    }
  }

  switch (conn->type) {
    case CONN_TYPE_DIR:
      dir_conn = TO_DIR_CONN(conn);
      if (conn->state < DIR_CONN_STATE_CLIENT_FINISHED) {
        /* It's a directory connection and connecting or fetching
         * failed: forget about this router, and maybe try again. */
        connection_dir_request_failed(dir_conn);
      }
      if (conn->purpose == DIR_PURPOSE_FETCH_RENDDESC)
        rend_client_desc_here(dir_conn->rend_query); /* give it a try */
      /* If we were trying to fetch a v2 rend desc and did not succeed,
       * retry as needed. (If a fetch is successful, the connection state
       * is changed to DIR_PURPOSE_HAS_FETCHED_RENDDESC to mark that
       * refetching is unnecessary.) */
       if (conn->purpose == DIR_PURPOSE_FETCH_RENDDESC_V2 &&
           dir_conn->rend_query &&
           strlen(dir_conn->rend_query) == REND_SERVICE_ID_LEN_BASE32)
        rend_client_refetch_v2_renddesc(dir_conn->rend_query);
      break;
    case CONN_TYPE_OR:
      or_conn = TO_OR_CONN(conn);
      /* Remember why we're closing this connection. */
      if (conn->state != OR_CONN_STATE_OPEN) {
        if (connection_or_nonopen_was_started_here(or_conn)) {
          rep_hist_note_connect_failed(or_conn->identity_digest, now);
          entry_guard_register_connect_status(or_conn->identity_digest,0,now);
          router_set_status(or_conn->identity_digest, 0);
          control_event_or_conn_status(or_conn, OR_CONN_EVENT_FAILED,
                  control_tls_error_to_reason(or_conn->tls_error));
        }
        /* Inform any pending (not attached) circs that they should
         * give up. */
        circuit_n_conn_done(TO_OR_CONN(conn), 0);
      } else if (conn->hold_open_until_flushed) {
        /* We only set hold_open_until_flushed when we're intentionally
         * closing a connection. */
        rep_hist_note_disconnect(or_conn->identity_digest, now);
        control_event_or_conn_status(or_conn, OR_CONN_EVENT_CLOSED,
                control_tls_error_to_reason(or_conn->tls_error));
      } else if (or_conn->identity_digest) {
        rep_hist_note_connection_died(or_conn->identity_digest, now);
        control_event_or_conn_status(or_conn, OR_CONN_EVENT_CLOSED,
                control_tls_error_to_reason(or_conn->tls_error));
      }
      /* Now close all the attached circuits on it. */
      circuit_unlink_all_from_or_conn(TO_OR_CONN(conn),
                                      END_CIRC_REASON_OR_CONN_CLOSED);
      break;
    case CONN_TYPE_AP:
      edge_conn = TO_EDGE_CONN(conn);
      if (edge_conn->socks_request->has_finished == 0) {
        /* since conn gets removed right after this function finishes,
         * there's no point trying to send back a reply at this point. */
        log_warn(LD_BUG,"Closing stream (marked at %s:%d) without sending"
                 " back a socks reply.",
                 conn->marked_for_close_file, conn->marked_for_close);
      }
      if (!edge_conn->end_reason) {
        log_warn(LD_BUG,"Closing stream (marked at %s:%d) without having"
                 " set end_reason.",
                 conn->marked_for_close_file, conn->marked_for_close);
      }
      if (edge_conn->dns_server_request) {
        log_warn(LD_BUG,"Closing stream (marked at %s:%d) without having"
                 " replied to DNS request.",
                 conn->marked_for_close_file, conn->marked_for_close);
        dnsserv_reject_request(edge_conn);
      }
      control_event_stream_status(edge_conn, STREAM_EVENT_CLOSED,
                                  edge_conn->end_reason);
      circ = circuit_get_by_edge_conn(edge_conn);
      if (circ)
        circuit_detach_stream(circ, edge_conn);
      break;
    case CONN_TYPE_EXIT:
      edge_conn = TO_EDGE_CONN(conn);
      circ = circuit_get_by_edge_conn(edge_conn);
      if (circ)
        circuit_detach_stream(circ, edge_conn);
      if (conn->state == EXIT_CONN_STATE_RESOLVING) {
        connection_dns_remove(edge_conn);
      }
      break;
  }
}

/** Return true iff connection_close_immediate() has been called on this
 * connection. */
#define CONN_IS_CLOSED(c) \
  ((c)->linked ? ((c)->linked_conn_is_closed) : ((c)->s < 0))

/** Close the underlying socket for <b>conn</b>, so we don't try to
 * flush it. Must be used in conjunction with (right before)
 * connection_mark_for_close().
 */
void
connection_close_immediate(connection_t *conn)
{
  assert_connection_ok(conn,0);
  if (CONN_IS_CLOSED(conn)) {
    log_err(LD_BUG,"Attempt to close already-closed connection.");
    tor_fragile_assert();
    return;
  }
  if (conn->outbuf_flushlen) {
    log_info(LD_NET,"fd %d, type %s, state %s, %d bytes on outbuf.",
             conn->s, conn_type_to_string(conn->type),
             conn_state_to_string(conn->type, conn->state),
             (int)conn->outbuf_flushlen);
  }

  connection_unregister_events(conn);

  if (conn->s >= 0)
    tor_close_socket(conn->s);
  conn->s = -1;
  if (conn->linked)
    conn->linked_conn_is_closed = 1;
  if (!connection_is_listener(conn)) {
    buf_clear(conn->outbuf);
    conn->outbuf_flushlen = 0;
  }
}

/** Mark <b>conn</b> to be closed next time we loop through
 * conn_close_if_marked() in main.c. */
void
_connection_mark_for_close(connection_t *conn, int line, const char *file)
{
  assert_connection_ok(conn,0);
  tor_assert(line);
  tor_assert(line < 1<<16); /* marked_for_close can only fit a uint16_t. */
  tor_assert(file);

  if (conn->marked_for_close) {
    log(LOG_WARN,LD_BUG,"Duplicate call to connection_mark_for_close at %s:%d"
        " (first at %s:%d)", file, line, conn->marked_for_close_file,
        conn->marked_for_close);
    tor_fragile_assert();
    return;
  }

  conn->marked_for_close = line;
  conn->marked_for_close_file = file;
  add_connection_to_closeable_list(conn);

  /* in case we're going to be held-open-til-flushed, reset
   * the number of seconds since last successful write, so
   * we get our whole 15 seconds */
  conn->timestamp_lastwritten = time(NULL);
}

/** Find each connection that has hold_open_until_flushed set to
 * 1 but hasn't written in the past 15 seconds, and set
 * hold_open_until_flushed to 0. This means it will get cleaned
 * up in the next loop through close_if_marked() in main.c.
 */
void
connection_expire_held_open(void)
{
  time_t now;
  smartlist_t *conns = get_connection_array();

  now = time(NULL);

  SMARTLIST_FOREACH(conns, connection_t *, conn,
  {
    /* If we've been holding the connection open, but we haven't written
     * for 15 seconds...
     */
    if (conn->hold_open_until_flushed) {
      tor_assert(conn->marked_for_close);
      if (now - conn->timestamp_lastwritten >= 15) {
        int severity;
        if (conn->type == CONN_TYPE_EXIT ||
            (conn->type == CONN_TYPE_DIR &&
             conn->purpose == DIR_PURPOSE_SERVER))
          severity = LOG_INFO;
        else
          severity = LOG_NOTICE;
        log_fn(severity, LD_NET,
               "Giving up on marked_for_close conn that's been flushing "
               "for 15s (fd %d, type %s, state %s).",
               conn->s, conn_type_to_string(conn->type),
               conn_state_to_string(conn->type, conn->state));
        conn->hold_open_until_flushed = 0;
      }
    }
  });
}

/** Create an AF_INET listenaddr struct.
 * <b>listenaddress</b> provides the host and optionally the port information
 * for the new structure.  If no port is provided in <b>listenaddress</b> then
 * <b>listenport</b> is used.
 *
 * If not NULL <b>readable_addrress</b> will contain a copy of the host part of
 * <b>listenaddress</b>.
 *
 * The listenaddr struct has to be freed by the caller.
 */
static struct sockaddr_in *
create_inet_sockaddr(const char *listenaddress, uint16_t listenport,
                     char **readable_address) {
  struct sockaddr_in *listenaddr = NULL;
  uint32_t addr;
  uint16_t usePort = 0;

  if (parse_addr_port(LOG_WARN,
                      listenaddress, readable_address, &addr, &usePort)<0) {
    log_warn(LD_CONFIG,
             "Error parsing/resolving ListenAddress %s", listenaddress);
    goto err;
  }
  if (usePort==0)
    usePort = listenport;

  listenaddr = tor_malloc_zero(sizeof(struct sockaddr_in));
  listenaddr->sin_addr.s_addr = htonl(addr);
  listenaddr->sin_family = AF_INET;
  listenaddr->sin_port = htons((uint16_t) usePort);

  return listenaddr;

 err:
  tor_free(listenaddr);
  return NULL;
}

#ifdef HAVE_SYS_UN_H
/** Create an AF_UNIX listenaddr struct.
 * <b>listenaddress</b> provides the path to the unix socket.
 *
 * Eventually <b>listenaddress</b> will also optionally contain user, group,
 * and file permissions for the new socket.  But not yet. XXX
 * Also, since we do not create the socket here the information doesn't help
 * here.
 *
 * If not NULL <b>readable_addrress</b> will contain a copy of the path part of
 * <b>listenaddress</b>.
 *
 * The listenaddr struct has to be freed by the caller.
 */
static struct sockaddr_un *
create_unix_sockaddr(const char *listenaddress, char **readable_address)
{
  struct sockaddr_un *sockaddr = NULL;

  sockaddr = tor_malloc_zero(sizeof(struct sockaddr_un));
  sockaddr->sun_family = AF_UNIX;
  strncpy(sockaddr->sun_path, listenaddress, sizeof(sockaddr->sun_path));

  if (readable_address)
    *readable_address = tor_strdup(listenaddress);

  return sockaddr;
}
#else
static struct sockaddr *
create_unix_sockaddr(const char *listenaddress, char **readable_address)
{
  (void)listenaddress;
  (void)readable_address;
  log_fn(LOG_ERR, LD_BUG,
         "Unix domain sockets not supported, yet we tried to create one.");