Commit e0204f21 authored by Nick Mathewson's avatar Nick Mathewson 🐘
Browse files

r16112@catbus: nickm | 2007-10-24 15:52:03 -0400 

 Fix logic for downloading consensuses: make getting an duplicate or not-currently-valid consensus count as a failure.  Make running out of time to get certificates count as a failure.  Delay while fetching certificates.


svn:r12159
parent 9767415d

ChangeLog

+5 −0
Changes for ChangeLog: 5 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -37,6 +37,11 @@ Changes in version 0.2.0.9-alpha - 2007-10-24 
      and download operations.

    - Reattempt certificate downloads immediately on failure, as long as

      we haven't failed a threshold number of times yet.

    - Delay retrying consensus downloads while we're downloading

      certificates to verify the one we just got.  Also, count getting a

      consensus that we already have (or one that isn't valid) as a failure,

      and count failing to get the certificates after 20 minutes as a

      failure.



  o Minor features (router descriptor cache):

    - If we find a cached-routers file that's been sitting around for more

doc/TODO

+7 −7
Changes for doc/TODO: 7 added lines, 7 removed lines.
Original line number Diff line number Diff line
@@ -48,11 +48,11 @@ Things we'd like to do in 0.2.0.x: 
        do more than that. I think some servers are forgetting the results

        of their first test, and then never seeing use.



  - Before 0.2.0.9-alpha (for nickm)

  o Before 0.2.0.9-alpha (for nickm)

    o Retry cert downloads as appropriate

    - Delay consensus download retry when there's a unverified consensus we're

    o Delay consensus download retry when there's a unverified consensus we're

      downloading the certs to check

      - But don't delay forever.

      o But don't delay forever.

    o Make new download types comply with should_delay_dir_fetches()

    o When DownloadExtraInfo is turned on for the first time, don't flip

      out and download the ancient history of the universe.
@@ -63,14 +63,14 @@ Things we'd like to do in 0.2.0.x: 
  - Proposals:

    . 101: Voting on the Tor Directory System (plus 103)

      . Validate information properly.

        - Dump certificates with the wrong time.  Or just warn?

        - When checking a consensus, make sure that its times are plausible.

        . Dump certificates with the wrong time.  Or just warn?

        . When checking a consensus, make sure that its times are plausible.

      . Start caching consensus documents once authorities make them;

        start downloading consensus documents once caches serve

        them

        - Code to delay next download while fetching certificates to verify

        o Code to delay next download while fetching certificates to verify

          a consensus we already got.

        - Code to retry consensus download if we got one we already have.

        o Code to retry consensus download if we got one we already have.

        - Use if-modified-since on consensus download

        - Use if-modified-since on certificate download

      - Controller support

src/or/directory.c

+1 −0
Changes for src/or/directory.c: 1 added line, 0 removed lines.
Original line number Diff line number Diff line
@@ -1449,6 +1449,7 @@ connection_dir_client_reached_eof(dir_connection_t *conn) 
             "'%s:%d'",(int) body_len, conn->_base.address, conn->_base.port);

    if (trusted_dirs_load_certs_from_string(body, 0)<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.");

src/or/networkstatus.c

+52 −9
Changes for src/or/networkstatus.c: 52 added lines, 9 removed lines.
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ static networkstatus_vote_t *current_consensus = NULL; 
 * have enough certificates to be happy about. */

static networkstatus_vote_t *consensus_waiting_for_certs = NULL;

static char *consensus_waiting_for_certs_body = NULL;

static time_t consensus_waiting_for_certs_set_at = 0;

static int consensus_waiting_for_certs_dl_failed = 0;



/** The last time we tried to download a networkstatus, or 0 for "never".  We

 * use this to rate-limit download attempts for directory caches (including
@@ -951,6 +953,8 @@ update_v2_networkstatus_cache_downloads(time_t now) 


/**DOCDOC*/

#define CONSENSUS_NETWORKSTATUS_MAX_DL_TRIES 8

/**DOCDOC*/

#define DELAY_WHILE_FETCHING_CERTS (20*60)



/** If we want to download a fresh consensus, launch a new download as

 * appropriate.  */
@@ -971,6 +975,17 @@ update_consensus_networkstatus_downloads(time_t now) 
                                     DIR_PURPOSE_FETCH_CONSENSUS))

    return; /* There's an in-progress download.*/



  if (consensus_waiting_for_certs) {

    if (consensus_waiting_for_certs_set_at + DELAY_WHILE_FETCHING_CERTS > now)

      return; /* We're still getting certs for this one. */

    else {

      if (!consensus_waiting_for_certs_dl_failed) {

        download_status_failed(&consensus_dl_status, 0);

        consensus_waiting_for_certs_dl_failed=1;

      }

    }

  }



  directory_get_from_dirserver(DIR_PURPOSE_FETCH_CONSENSUS,

                               ROUTER_PURPOSE_GENERAL, NULL, 1);

}
@@ -1153,7 +1168,9 @@ networkstatus_copy_old_consensus_info(networkstatus_vote_t *new_c, 
 * <b>consensus</b>.  If we don't have enough certificates to validate it,

 * store it in consensus_waiting_for_certs and launch a certificate fetch.

 *

 * Return 0 on success, -1 on failure. */

 * Return 0 on success, -1 on failure.  On -1, caller should increment

 * the failure count as appropriate.

 */

int

networkstatus_set_current_consensus(const char *consensus, int from_cache,

                                    int was_waiting_for_certs)
@@ -1170,6 +1187,20 @@ networkstatus_set_current_consensus(const char *consensus, int from_cache, 
    goto done;

  }



  if (current_consensus &&

      !memcmp(c->networkstatus_digest, current_consensus->networkstatus_digest,

              DIGEST_LEN)) {

    /* We already have this one. That's a failure. */

    log_info(LD_DIR, "Got a consensus we already have");

    goto done;

  }



  if (current_consensus && c->valid_after <= current_consensus->valid_after) {

    /* We have a newer one. */

    log_info(LD_DIR, "Got a consensus at least as old as the one we have");

    goto done;

  }



  consensus_fname = get_datadir_fname("cached-consensus");

  unverified_fname = get_datadir_fname("unverified-consensus");
@@ -1187,34 +1218,33 @@ networkstatus_set_current_consensus(const char *consensus, int from_cache, 
        tor_free(consensus_waiting_for_certs_body);

        consensus_waiting_for_certs = c;

        consensus_waiting_for_certs_body = tor_strdup(consensus);

        /*XXXX020 delay next update. NMNM */

        consensus_waiting_for_certs_set_at = now;

        consensus_waiting_for_certs_dl_failed = 0;

        if (!from_cache) {

          write_str_to_file(unverified_fname, consensus, 0);

        }

        authority_certs_fetch_missing(c, now);

        /* This case is not a success or a failure until we get the certs

         * or fail to get the certs. */

        result = 0;

      } else {

        /* Even if we had enough signatures, we'd never use this as the

         * latest consensus. */

        if (was_waiting_for_certs && from_cache)

          unlink(unverified_fname);

      }

      download_status_reset(&consensus_dl_status); /*XXXX020 not quite right.*/

      result = 0;

      goto done;

    } else  {

      /* This can never be signed enough Kill it. */

      /* This can never be signed enough:  Kill it. */

      if (!was_waiting_for_certs)

        log_warn(LD_DIR, "Not enough good signatures on networkstatus "

                 "consensus");

      if (was_waiting_for_certs && from_cache)

      if (was_waiting_for_certs && (r < -1) && from_cache)

        unlink(unverified_fname);

      networkstatus_vote_free(c);

      goto done;

    }

  }



  download_status_reset(&consensus_dl_status); /*XXXX020 not quite right.*/



  /* XXXX020 check dates for plausibility.  Don't trust a consensus whose

   * valid-after date is very far in the future. */
@@ -1233,10 +1263,21 @@ networkstatus_set_current_consensus(const char *consensus, int from_cache, 
    consensus_waiting_for_certs = NULL;

    if (consensus != consensus_waiting_for_certs_body)

      tor_free(consensus_waiting_for_certs_body);

    consensus_waiting_for_certs_set_at = 0;

    consensus_waiting_for_certs_dl_failed = 0;

    unlink(unverified_fname);

  }



  /* Reset the failure count only if this consensus is actually valid. */

  if (c->valid_after <= now && now <= c->valid_until) {

    download_status_reset(&consensus_dl_status);

  } else {

    if (!from_cache)

      download_status_failed(&consensus_dl_status, 0);

  }



  current_consensus = c;

  c = NULL; /* Prevent free. */



  update_consensus_networkstatus_fetch_time(now);

  dirvote_recalculate_timing(get_options(), now);
@@ -1253,6 +1294,8 @@ networkstatus_set_current_consensus(const char *consensus, int from_cache, 


  result = 0;

 done:

  if (c)

    networkstatus_vote_free(c);

  tor_free(consensus_fname);

  tor_free(unverified_fname);

  return result;