control.c

关于tor匿名通信的源代码

    *outp++ = '\n';
  }

  *outp = '\0';
  return outp - *out;
}

/** If the first <b>in_len_max</b> characters in <b>start<b> contain a
 * double-quoted string with escaped characters, return the length of that
 * string (as encoded, including quotes).  Otherwise return -1. */
static INLINE int
get_escaped_string_length(const char *start, size_t in_len_max,
                          int *chars_out)
{
  const char *cp, *end;
  int chars = 0;

  if (*start != '\"')
    return -1;

  cp = start+1;
  end = start+in_len_max;

  /* Calculate length. */
  while (1) {
    if (cp >= end) {
      return -1; /* Too long. */
    } else if (*cp == '\\') {
      if (++cp == end)
        return -1; /* Can't escape EOS. */
      ++cp;
      ++chars;
    } else if (*cp == '\"') {
      break;
    } else {
      ++cp;
      ++chars;
    }
  }
  if (chars_out)
    *chars_out = chars;
  return (int)(cp - start+1);
}

/** As decode_escaped_string, but does not decode the string: copies the
 * entire thing, including quotation marks. */
static const char *
extract_escaped_string(const char *start, size_t in_len_max,
                       char **out, size_t *out_len)
{
  int length = get_escaped_string_length(start, in_len_max, NULL);
  if (length<0)
    return NULL;
  *out_len = length;
  *out = tor_strndup(start, *out_len);
  return start+length;
}

/** Given a pointer to a string starting at <b>start</b> containing
 * <b>in_len_max</b> characters, decode a string beginning with one double
 * quote, containing any number of non-quote characters or characters escaped
 * with a backslash, and ending with a final double quote.  Place the resulting
 * string (unquoted, unescaped) into a newly allocated string in *<b>out</b>;
 * store its length in <b>out_len</b>.  On success, return a pointer to the
 * character immediately following the escaped string.  On failure, return
 * NULL. */
static const char *
decode_escaped_string(const char *start, size_t in_len_max,
                   char **out, size_t *out_len)
{
  const char *cp, *end;
  char *outp;
  int len, n_chars = 0;

  len = get_escaped_string_length(start, in_len_max, &n_chars);
  if (len<0)
    return NULL;

  end = start+len-1; /* Index of last quote. */
  tor_assert(*end == '\"');
  outp = *out = tor_malloc(len+1);
  *out_len = n_chars;

  cp = start+1;
  while (cp < end) {
    if (*cp == '\\')
      ++cp;
    *outp++ = *cp++;
  }
  *outp = '\0';
  tor_assert((outp - *out) == (int)*out_len);

  return end+1;
}

/** Acts like sprintf, but writes its formatted string to the end of
 * <b>conn</b>-\>outbuf.  The message may be truncated if it is too long,
 * but it will always end with a CRLF sequence.
 *
 * Currently the length of the message is limited to 1024 (including the
 * ending \r\n\0. */
static void
connection_printf_to_buf(control_connection_t *conn, const char *format, ...)
{
#define CONNECTION_PRINTF_TO_BUF_BUFFERSIZE 1024
  va_list ap;
  char buf[CONNECTION_PRINTF_TO_BUF_BUFFERSIZE];
  int r;
  size_t len;
  va_start(ap,format);
  r = tor_vsnprintf(buf, sizeof(buf), format, ap);
  va_end(ap);
  if (r<0) {
    log_warn(LD_BUG, "Unable to format string for controller.");
    return;
  }
  len = strlen(buf);
  if (memcmp("\r\n\0", buf+len-2, 3)) {
    buf[CONNECTION_PRINTF_TO_BUF_BUFFERSIZE-1] = '\0';
    buf[CONNECTION_PRINTF_TO_BUF_BUFFERSIZE-2] = '\n';
    buf[CONNECTION_PRINTF_TO_BUF_BUFFERSIZE-3] = '\r';
  }
  connection_write_to_buf(buf, len, TO_CONN(conn));
}

/** Send a "DONE" message down the control connection <b>conn</b>. */
static void
send_control_done(control_connection_t *conn)
{
  connection_write_str_to_buf("250 OK\r\n", conn);
}

/* Send an event to all v1 controllers that are listening for code
 * <b>event</b>.  The event's body is given by <b>msg</b>.
 *
 * If <b>which</b> & SHORT_NAMES, the event contains short-format names: send
 * it to controllers that haven't enabled the VERBOSE_NAMES feature.  If
 * <b>which</b> & LONG_NAMES, the event contains long-format names: send it
 * to contollers that <em>have</em> enabled VERBOSE_NAMES.
 *
 * The EXTENDED_FORMAT and NONEXTENDED_FORMAT flags behave similarly with
 * respect to the EXTENDED_EVENTS feature. */
static void
send_control_event_string(uint16_t event, event_format_t which,
                          const char *msg)
{
  smartlist_t *conns = get_connection_array();
  tor_assert(event >= _EVENT_MIN && event <= _EVENT_MAX);

  SMARTLIST_FOREACH(conns, connection_t *, conn,
  {
    if (conn->type == CONN_TYPE_CONTROL &&
        !conn->marked_for_close &&
        conn->state == CONTROL_CONN_STATE_OPEN) {
      control_connection_t *control_conn = TO_CONTROL_CONN(conn);
      if (control_conn->use_long_names) {
        if (!(which & LONG_NAMES))
          continue;
      } else {
        if (!(which & SHORT_NAMES))
          continue;
      }
      if (control_conn->use_extended_events) {
        if (!(which & EXTENDED_FORMAT))
          continue;
      } else {
        if (!(which & NONEXTENDED_FORMAT))
          continue;
      }
      if (control_conn->event_mask & (1<<event)) {
        int is_err = 0;
        connection_write_to_buf(msg, strlen(msg), TO_CONN(control_conn));
        if (event == EVENT_ERR_MSG)
          is_err = 1;
        else if (event == EVENT_STATUS_GENERAL)
          is_err = !strcmpstart(msg, "STATUS_GENERAL ERR ");
        else if (event == EVENT_STATUS_CLIENT)
          is_err = !strcmpstart(msg, "STATUS_CLIENT ERR ");
        else if (event == EVENT_STATUS_SERVER)
          is_err = !strcmpstart(msg, "STATUS_SERVER ERR ");
        if (is_err)
          connection_handle_write(TO_CONN(control_conn), 1);
      }
    }
  });
}

/** Helper for send_control1_event and send_control1_event_extended:
 * Send an event to all v1 controllers that are listening for code
 * <b>event</b>.  The event's body is created by the printf-style format in
 * <b>format</b>, and other arguments as provided.
 *
 * If <b>extended</b> is true, and the format contains a single '@' character,
 * it will be replaced with a space and all text after that character will be
 * sent only to controllers that have enabled extended events.
 *
 * Currently the length of the message is limited to 1024 (including the
 * ending \n\r\0). */
static void
send_control_event_impl(uint16_t event, event_format_t which, int extended,
                         const char *format, va_list ap)
{
  /* This is just a little longer than the longest allowed log message */
#define SEND_CONTROL1_EVENT_BUFFERSIZE 10064
  int r;
  char buf[SEND_CONTROL1_EVENT_BUFFERSIZE];
  size_t len;
  char *cp;

  r = tor_vsnprintf(buf, sizeof(buf), format, ap);
  if (r<0) {
    log_warn(LD_BUG, "Unable to format event for controller.");
    return;
  }

  len = strlen(buf);
  if (memcmp("\r\n\0", buf+len-2, 3)) {
    /* if it is not properly terminated, do it now */
    buf[SEND_CONTROL1_EVENT_BUFFERSIZE-1] = '\0';
    buf[SEND_CONTROL1_EVENT_BUFFERSIZE-2] = '\n';
    buf[SEND_CONTROL1_EVENT_BUFFERSIZE-3] = '\r';
  }

  if (extended && (cp = strchr(buf, '@'))) {
    which &= ~ALL_FORMATS;
    *cp = ' ';
    send_control_event_string(event, which|EXTENDED_FORMAT, buf);
    memcpy(cp, "\r\n\0", 3);
    send_control_event_string(event, which|NONEXTENDED_FORMAT, buf);
  } else {
    send_control_event_string(event, which|ALL_FORMATS, buf);
  }
}

/* Send an event to all v1 controllers that are listening for code
 * <b>event</b>.  The event's body is created by the printf-style format in
 * <b>format</b>, and other arguments as provided.
 *
 * Currently the length of the message is limited to 1024 (including the
 * ending \n\r\0. */
static void
send_control_event(uint16_t event, event_format_t which,
                    const char *format, ...)
{
  va_list ap;
  va_start(ap, format);
  send_control_event_impl(event, which, 0, format, ap);
  va_end(ap);
}

/* Send an event to all v1 controllers that are listening for code
 * <b>event</b>.  The event's body is created by the printf-style format in
 * <b>format</b>, and other arguments as provided.
 *
 * If the format contains a single '@' character, it will be replaced with a
 * space and all text after that character will be sent only to controllers
 * that have enabled extended events.
 *
 * Currently the length of the message is limited to 1024 (including the
 * ending \n\r\0. */
static void
send_control_event_extended(uint16_t event, event_format_t which,
                             const char *format, ...)
{
  va_list ap;
  va_start(ap, format);
  send_control_event_impl(event, which, 1, format, ap);
  va_end(ap);
}

/** Given a text circuit <b>id</b>, return the corresponding circuit. */
static origin_circuit_t *
get_circ(const char *id)
{
  uint32_t n_id;
  int ok;
  n_id = (uint32_t) tor_parse_ulong(id, 10, 0, UINT32_MAX, &ok, NULL);
  if (!ok)
    return NULL;
  return circuit_get_by_global_id(n_id);
}

/** Given a text stream <b>id</b>, return the corresponding AP connection. */
static edge_connection_t *
get_stream(const char *id)
{
  uint32_t n_id;
  int ok;
  edge_connection_t *conn;
  n_id = (uint32_t) tor_parse_ulong(id, 10, 0, UINT32_MAX, &ok, NULL);
  if (!ok)
    return NULL;
  conn = connection_get_by_global_id(n_id);
  if (!conn || conn->_base.type != CONN_TYPE_AP)
    return NULL;
  return conn;
}

/** Helper for setconf and resetconf. Acts like setconf, except
 * it passes <b>use_defaults</b> on to options_trial_assign().  Modifies the
 * contents of body.
 */
static int
control_setconf_helper(control_connection_t *conn, uint32_t len, char *body,
                       int use_defaults)
{
  setopt_err_t opt_err;
  config_line_t *lines=NULL;
  char *start = body;
  char *errstring = NULL;
  const int clear_first = 1;

  char *config;
  smartlist_t *entries = smartlist_create();

  /* We have a string, "body", of the format '(key(=val|="val")?)' entries
   * separated by space.  break it into a list of configuration entries. */
  while (*body) {
    char *eq = body;
    char *key;
    char *entry;
    while (!TOR_ISSPACE(*eq) && *eq != '=')
      ++eq;
    key = tor_strndup(body, eq-body);
    body = eq+1;
    if (*eq == '=') {
      char *val=NULL;
      size_t val_len=0;
      size_t ent_len;
      if (*body != '\"') {
        char *val_start = body;
        while (!TOR_ISSPACE(*body))
          body++;
        val = tor_strndup(val_start, body-val_start);
        val_len = strlen(val);
      } else {
        body = (char*)extract_escaped_string(body, (len - (body-start)),
                                             &val, &val_len);
        if (!body) {
          connection_write_str_to_buf("551 Couldn't parse string\r\n", conn);
          SMARTLIST_FOREACH(entries, char *, cp, tor_free(cp));
          smartlist_free(entries);
          tor_free(key);
          return 0;
        }
      }
      ent_len = strlen(key)+val_len+3;
      entry = tor_malloc(ent_len+1);
      tor_snprintf(entry, ent_len, "%s %s", key, val);
      tor_free(key);
      tor_free(val);
    } else {
      entry = key;
    }
    smartlist_add(entries, entry);
    while (TOR_ISSPACE(*body))
      ++body;
  }

  smartlist_add(entries, tor_strdup(""));
  config = smartlist_join_strings(entries, "\n", 0, NULL);
  SMARTLIST_FOREACH(entries, char *, cp, tor_free(cp));
  smartlist_free(entries);

  if (config_get_lines(config, &lines) < 0) {