Prop210: Add schedules for simultaneous client consensus downloads

Prop210: Add attempt-based connection schedules

Existing tor schedules increment the schedule position on failure,
then retry the connection after the scheduled time.

To make multiple simultaneous connections, we need to increment the
schedule position when making each attempt, then retry a (potentially
simultaneous) connection after the scheduled time.

(Also change find_dl_schedule_and_len to find_dl_schedule, as it no
longer takes or returns len.)

Prop210: Add multiple simultaneous consensus downloads for clients

Make connections on TestingClientBootstrapConsensus*DownloadSchedule,
incrementing the schedule each time the client attempts to connect.

Check if the number of downloads is less than
TestingClientBootstrapConsensusMaxInProgressTries before trying any
more connections.

1 files changed, 11 insertions, 2 deletions

diff --git a/src/or/directory.h b/src/or/directory.h
index bdcc1a23c6..4255868d3a 100644
--- a/src/or/directory.h
+++ b/src/or/directory.h
@@ -92,6 +92,8 @@ int router_supports_extrainfo(const char *identity_digest, int is_authority);
 time_t download_status_increment_failure(download_status_t *dls,
                                          int status_code, const char *item,
                                          int server, time_t now);
+time_t download_status_increment_attempt(download_status_t *dls,
+                                         const char *item,  time_t now);
 /** Increment the failure count of the download_status_t <b>dls</b>, with
  * the optional status code <b>sc</b>. */
 #define download_status_failed(dls, sc)                                 \
@@ -107,8 +109,9 @@ static INLINE int
 download_status_is_ready(download_status_t *dls, time_t now,
                          int max_failures)
 {
-  return (dls->n_download_failures <= max_failures
-          && dls->next_attempt_at <= now);
+  int under_failure_limit = (dls->n_download_failures <= max_failures
+                             && dls->n_download_attempts <= max_failures);
+  return (under_failure_limit && dls->next_attempt_at <= now);
 }
 
 static void download_status_mark_impossible(download_status_t *dl);
@@ -117,9 +120,12 @@ static INLINE void
 download_status_mark_impossible(download_status_t *dl)
 {
   dl->n_download_failures = IMPOSSIBLE_TO_DOWNLOAD;
+  dl->n_download_attempts = IMPOSSIBLE_TO_DOWNLOAD;
 }
 
 int download_status_get_n_failures(const download_status_t *dls);
+int download_status_get_n_attempts(const download_status_t *dls);
+time_t download_status_get_next_attempt_at(const download_status_t *dls);
 
 #ifdef TOR_UNIT_TESTS
 /* Used only by directory.c and test_dir.c */
@@ -133,6 +139,9 @@ STATIC int directory_handle_command_get(dir_connection_t *conn,
                                         const char *headers,
                                         const char *req_body,
                                         size_t req_body_len);
+STATIC int download_status_schedule_get_delay(download_status_t *dls,
+                                              const smartlist_t *schedule,
+                                              time_t now);
 #endif
 
 #endif