directory.c

关于tor匿名通信的源代码

      log_warn(LD_PROTOCOL,
               "'fetch' response too large (server '%s:%d'). Closing.",
               conn->_base.address, conn->_base.port);
      return -1;
    case 0:
      log_info(LD_HTTP,
               "'fetch' response not all here, but we're at eof. Closing.");
      return -1;
    /* case 1, fall through */
  }
  orig_len = body_len;

  if (parse_http_response(headers, &status_code, &date_header,
                          &compression, &reason) < 0) {
    log_warn(LD_HTTP,"Unparseable headers (server '%s:%d'). Closing.",
             conn->_base.address, conn->_base.port);
    tor_free(body); tor_free(headers);
    return -1;
  }
  if (!reason) reason = tor_strdup("[no reason given]");

  log_debug(LD_DIR,
            "Received response from directory server '%s:%d': %d %s",
            conn->_base.address, conn->_base.port, status_code,
            escaped(reason));

  /* now check if it's got any hints for us about our IP address. */
  if (conn->dirconn_direct) {
    char *guess = http_get_header(headers, X_ADDRESS_HEADER);
    if (guess) {
      router_new_address_suggestion(guess, conn);
      tor_free(guess);
    }
  }

  if (date_header > 0) {
    /* The date header was written very soon after we sent our request,
     * so compute the skew as the difference between sending the request
     * and the date header.  (We used to check now-date_header, but that's
     * inaccurate if we spend a lot of time downloading.)
     */
    delta = conn->_base.timestamp_lastwritten - date_header;
    if (labs(delta)>ALLOW_DIRECTORY_TIME_SKEW) {
      char dbuf[64];
      int trusted = router_digest_is_trusted_dir(conn->identity_digest);
      format_time_interval(dbuf, sizeof(dbuf), delta);
      log_fn(trusted ? LOG_WARN : LOG_INFO,
             LD_HTTP,
             "Received directory with skewed time (server '%s:%d'): "
             "It seems that our clock is %s by %s, or that theirs is %s. "
             "Tor requires an accurate clock to work: please check your time "
             "and date settings.",
             conn->_base.address, conn->_base.port,
             delta>0 ? "ahead" : "behind", dbuf,
             delta>0 ? "behind" : "ahead");
      skewed = 1; /* don't check the recommended-versions line */
      control_event_general_status(trusted ? LOG_WARN : LOG_NOTICE,
                               "CLOCK_SKEW SKEW=%ld SOURCE=DIRSERV:%s:%d",
                               delta, conn->_base.address, conn->_base.port);
    } else {
      log_debug(LD_HTTP, "Time on received directory is within tolerance; "
                "we are %ld seconds skewed.  (That's okay.)", delta);
    }
  }
  (void) skewed; /* skewed isn't used yet. */

  if (status_code == 503 && body_len < 16) {
    routerstatus_t *rs;
    trusted_dir_server_t *ds;
    log_info(LD_DIR,"Received http status code %d (%s) from server "
             "'%s:%d'. I'll try again soon.",
             status_code, escaped(reason), conn->_base.address,
             conn->_base.port);
    if ((rs = router_get_consensus_status_by_id(conn->identity_digest)))
      rs->last_dir_503_at = now;
    if ((ds = router_get_trusteddirserver_by_digest(conn->identity_digest)))
      ds->fake_status.last_dir_503_at = now;

    tor_free(body); tor_free(headers); tor_free(reason);
    return -1;
  } else if (status_code == 503) {
    /* XXXX022 Remove this once every server with bug 539 is obsolete. */
    log_info(LD_DIR, "Server at '%s:%d' sent us a 503 response, but included "
             "a body anyway.  We'll pretend it gave us a 200.",
             conn->_base.address, conn->_base.port);
    status_code = 200;
  }

  plausible = body_is_plausible(body, body_len, conn->_base.purpose);
  if (compression != NO_METHOD || !plausible) {
    char *new_body = NULL;
    size_t new_len = 0;
    compress_method_t guessed = detect_compression_method(body, body_len);
    if (compression == UNKNOWN_METHOD || guessed != compression) {
      /* Tell the user if we don't believe what we're told about compression.*/
      const char *description1, *description2;
      if (compression == ZLIB_METHOD)
        description1 = "as deflated";
      else if (compression == GZIP_METHOD)
        description1 = "as gzipped";
      else if (compression == NO_METHOD)
        description1 = "as uncompressed";
      else
        description1 = "with an unknown Content-Encoding";
      if (guessed == ZLIB_METHOD)
        description2 = "deflated";
      else if (guessed == GZIP_METHOD)
        description2 = "gzipped";
      else if (!plausible)
        description2 = "confusing binary junk";
      else
        description2 = "uncompressed";

      log_info(LD_HTTP, "HTTP body from server '%s:%d' was labeled %s, "
               "but it seems to be %s.%s",
               conn->_base.address, conn->_base.port, description1,
               description2,
               (compression>0 && guessed>0)?"  Trying both.":"");
    }
    /* Try declared compression first if we can. */
    if (compression == GZIP_METHOD  || compression == ZLIB_METHOD)
      tor_gzip_uncompress(&new_body, &new_len, body, body_len, compression,
                          !allow_partial, LOG_PROTOCOL_WARN);
    /* Okay, if that didn't work, and we think that it was compressed
     * differently, try that. */
    if (!new_body &&
        (guessed == GZIP_METHOD || guessed == ZLIB_METHOD) &&
        compression != guessed)
      tor_gzip_uncompress(&new_body, &new_len, body, body_len, guessed,
                          !allow_partial, LOG_PROTOCOL_WARN);
    /* If we're pretty sure that we have a compressed directory, and
     * we didn't manage to uncompress it, then warn and bail. */
    if (!plausible && !new_body) {
      log_fn(LOG_PROTOCOL_WARN, LD_HTTP,
             "Unable to decompress HTTP body (server '%s:%d').",
             conn->_base.address, conn->_base.port);
      tor_free(body); tor_free(headers); tor_free(reason);
      return -1;
    }
    if (new_body) {
      tor_free(body);
      body = new_body;
      body_len = new_len;
      was_compressed = 1;
    }
  }

  if (conn->_base.purpose == DIR_PURPOSE_FETCH_DIR) {
    /* fetch/process the directory to cache it. */
    log_info(LD_DIR,"Received directory (size %d) from server '%s:%d'",
             (int)body_len, conn->_base.address, conn->_base.port);
    if (status_code != 200) {
      log_warn(LD_DIR,"Received http status code %d (%s) from server "
               "'%s:%d' while fetching directory. I'll try again soon.",
               status_code, escaped(reason), conn->_base.address,
               conn->_base.port);
      tor_free(body); tor_free(headers); tor_free(reason);
      return -1;
    }
    if (router_parse_directory(body) < 0) {
      log_notice(LD_DIR,"I failed to parse the directory I fetched from "
                 "'%s:%d'. Ignoring.", conn->_base.address, conn->_base.port);
    }
    note_request(was_compressed?"dl/dir.z":"dl/dir", orig_len);
  }

  if (conn->_base.purpose == DIR_PURPOSE_FETCH_RUNNING_LIST) {
    /* just update our list of running routers, if this list is new info */
    log_info(LD_DIR,"Received running-routers list (size %d)", (int)body_len);
    if (status_code != 200) {
      log_warn(LD_DIR,"Received http status code %d (%s) from server "
               "'%s:%d' while fetching running-routers. I'll try again soon.",
               status_code, escaped(reason), conn->_base.address,
               conn->_base.port);
      tor_free(body); tor_free(headers); tor_free(reason);
      return -1;
    }
    if (router_parse_runningrouters(body)<0) {
      log_warn(LD_DIR,
               "Bad running-routers from server '%s:%d'. I'll try again soon.",
               conn->_base.address, conn->_base.port);
      tor_free(body); tor_free(headers); tor_free(reason);
      return -1;
    }
    note_request(was_compressed?"dl/running-routers.z":
                 "dl/running-routers", orig_len);
  }

  if (conn->_base.purpose == DIR_PURPOSE_FETCH_NETWORKSTATUS) {
    smartlist_t *which = NULL;
    networkstatus_source_t source;
    char *cp;
    log_info(LD_DIR,"Received networkstatus objects (size %d) from server "
             "'%s:%d'",(int) body_len, conn->_base.address, conn->_base.port);
    if (status_code != 200) {
      log_warn(LD_DIR,
           "Received http status code %d (%s) from server "
           "'%s:%d' while fetching \"/tor/status/%s\". I'll try again soon.",
           status_code, escaped(reason), conn->_base.address,
           conn->_base.port, conn->requested_resource);
      tor_free(body); tor_free(headers); tor_free(reason);
      connection_dir_download_networkstatus_failed(conn, status_code);
      return -1;
    }
    note_request(was_compressed?"dl/status.z":"dl/status", orig_len);
    if (conn->requested_resource &&
        !strcmpstart(conn->requested_resource,"fp/")) {
      source = NS_FROM_DIR_BY_FP;
      which = smartlist_create();
      dir_split_resource_into_fingerprints(conn->requested_resource+3,
                                           which, NULL, 0, 0);
    } else if (conn->requested_resource &&
               !strcmpstart(conn->requested_resource, "all")) {
      source = NS_FROM_DIR_ALL;
      which = smartlist_create();
      SMARTLIST_FOREACH(router_get_trusted_dir_servers(),
                        trusted_dir_server_t *, ds,
        {
          char *hex = tor_malloc(HEX_DIGEST_LEN+1);
          base16_encode(hex, HEX_DIGEST_LEN+1, ds->digest, DIGEST_LEN);
          smartlist_add(which, hex);
        });
    } else {
      /* XXXX Can we even end up here? -- weasel*/
      source = NS_FROM_DIR_BY_FP;
      log_warn(LD_BUG, "We received a networkstatus but we didn't ask "
                       "for it by fp, nor did we ask for all.");
    }
    cp = body;
    while (*cp) {
      char *next = strstr(cp, "\nnetwork-status-version");
      if (next)
        next[1] = '\0';
      /* learn from it, and then remove it from 'which' */
      if (router_set_networkstatus_v2(cp, now, source, which)<0)
        break;
      if (next) {
        next[1] = 'n';
        cp = next+1;
      } else
        break;
    }
    /* launches router downloads as needed */
    routers_update_all_from_networkstatus(now, 2);
    directory_info_has_arrived(now, 0);
    if (which) {
      if (smartlist_len(which)) {
        dir_networkstatus_download_failed(which, status_code);
      }
      SMARTLIST_FOREACH(which, char *, s, tor_free(s));
      smartlist_free(which);
    }
  }

  if (conn->_base.purpose == DIR_PURPOSE_FETCH_CONSENSUS) {
    int r;
    if (status_code != 200) {
      int severity = (status_code == 304) ? LOG_INFO : LOG_WARN;
      log(severity, LD_DIR,
          "Received http status code %d (%s) from server "
          "'%s:%d' while fetching consensus directory.",
           status_code, escaped(reason), conn->_base.address,
           conn->_base.port);
      tor_free(body); tor_free(headers); tor_free(reason);
      networkstatus_consensus_download_failed(status_code);
      return -1;
    }
    log_info(LD_DIR,"Received consensus directory (size %d) from server "
             "'%s:%d'",(int) body_len, conn->_base.address, conn->_base.port);
    if ((r=networkstatus_set_current_consensus(body, 0))<0) {
      log_fn(r<-1?LOG_WARN:LOG_INFO, LD_DIR,
             "Unable to load consensus directory downloaded from "
             "server '%s:%d'. I'll try again soon.",
             conn->_base.address, conn->_base.port);
      tor_free(body); tor_free(headers); tor_free(reason);
      networkstatus_consensus_download_failed(0);
      return -1;
    }
    /* launches router downloads as needed */
    routers_update_all_from_networkstatus(now, 3);
    directory_info_has_arrived(now, 0);
    log_info(LD_DIR, "Successfully loaded consensus.");
  }

  if (conn->_base.purpose == DIR_PURPOSE_FETCH_CERTIFICATE) {
    if (status_code != 200) {
      log_warn(LD_DIR,
          "Received http status code %d (%s) from server "
          "'%s:%d' while fetching \"/tor/keys/%s\".",
           status_code, escaped(reason), conn->_base.address,
           conn->_base.port, conn->requested_resource);
      connection_dir_download_cert_failed(conn, status_code);
      tor_free(body); tor_free(headers); tor_free(reason);
      return -1;
    }
    log_info(LD_DIR,"Received authority certificates (size %d) from server "
             "'%s:%d'",(int) body_len, conn->_base.address, conn->_base.port);
    if (trusted_dirs_load_certs_from_string(body, 0, 1)<0) {
      log_warn(LD_DIR, "Unable to parse fetched certificates");
      connection_dir_download_cert_failed(conn, status_code);
    } else {
      directory_info_has_arrived(now, 0);
      log_info(LD_DIR, "Successfully loaded certificates from fetch.");
    }
  }
  if (conn->_base.purpose == DIR_PURPOSE_FETCH_STATUS_VOTE) {
    const char *msg;
    int st;
    log_info(LD_DIR,"Got votes (size %d) from server %s:%d",
             (int) body_len, conn->_base.address, conn->_base.port);
    if (status_code != 200) {
      log_warn(LD_DIR,
             "Received http status code %d (%s) from server "
             "'%s:%d' while fetching \"/tor/status-vote/next/%s.z\".",
             status_code, escaped(reason), conn->_base.address,
             conn->_base.port, conn->requested_resource);
      tor_free(body); tor_free(headers); tor_free(reason);
      return -1;
    }
    dirvote_add_vote(body, &msg, &st);
    if (st > 299) {
      log_warn(LD_DIR, "Error adding retrieved vote: %s", msg);
    } else {
      log_info(LD_DIR, "Added vote(s) successfully [msg: %s]", msg);
    }
  }
  if (conn->_base.purpose == DIR_PURPOSE_FETCH_DETACHED_SIGNATURES) {
    const char *msg = NULL;
    log_info(LD_DIR,"Got detached signatures (size %d) from server %s:%d",
             (int) body_len, conn->_base.address, conn->_base.port);
    if (status_code != 200) {
      log_warn(LD_DIR,
        "