Write bidirectional connection stats in single line.

There's no need to have a separate line conn-stats-end for the end date
and interval length with only a single line conn-bi-direct following.

doc/spec/dir-spec.txt

@@ -848,27 +848,17 @@
         Mean number of circuits that are included in any of the deciles,
         rounded up to the next integer.
 
-    "conn-stats-end" YYYY-MM-DD HH:MM:SS (NSEC s) NL
-        [At most once]
-
-        YYYY-MM-DD HH:MM:SS defines the end of the included connection
-        statistics measurement interval of length NSEC seconds (86400
-        seconds by default).
-
-        A "conn-stats-end" line, as well as any other "conn-*" line,
-        is first added after the relay has been running for at least 24
-        hours.
-
-    "conn-bi-direct" BELOW,READ,WRITE,BOTH NL
+    "conn-bi-direct" YYYY-MM-DD HH:MM:SS (NSEC s) BELOW,READ,WRITE,BOTH NL
         [At most once]
 
         Number of connections, split into 10-second intervals, that are
-        used uni-directionally or bi-directionally.  Every 10 seconds,
-        we determine for every connection whether we read and wrote less
-        than a threshold of 20 KiB (BELOW), read at least 10 times more
-        than we wrote (READ), wrote at least 10 times more than we read
-        (WRITE), or read and wrote more than the threshold, but not 10
-        times more in either direction (BOTH).  After classifying a
+        used uni-directionally or bi-directionally as observed in the NSEC
+        seconds (usually 86400 seconds) before YYYY-MM-DD HH:MM:SS.  Every
+        10 seconds, we determine for every connection whether we read and
+        wrote less than a threshold of 20 KiB (BELOW), read at least 10
+        times more than we wrote (READ), wrote at least 10 times more than
+        we read (WRITE), or read and wrote more than the threshold, but
+        not 10 times more in either direction (BOTH).  After classifying a
         connection, read and write counters are reset for the next
         10-second interval.
 

doc/tor.1.txt

@@ -1027,7 +1027,7 @@ is non-zero):
     When this option is enabled, Tor writes statistics on the number of relayed
     bytes and opened stream per exit port to disk every 24 hours. (Default: 0)
 
-**ConnDirectionStats** **0**|**1**::
+**ConnDirectionStatistics** **0**|**1**::
     When this option is enabled, Tor writes statistics on the bidirectional use
     of connections to disk every 24 hours. (Default: 0)
 

src/or/rephist.c

@@ -2592,8 +2592,7 @@ rep_hist_format_conn_stats(time_t now)
     return NULL; /* Not initialized. */
 
   format_iso_time(written, now);
-  tor_asprintf(&result, "conn-stats-end %s (%d s)\n"
-               "conn-bi-direct %d,%d,%d,%d\n",
+  tor_asprintf(&result, "conn-bi-direct %s (%d s) %d,%d,%d,%d\n",
                written,
                (unsigned) (now - start_of_conn_stats_interval),
                below_threshold,

src/or/router.c

@@ -2053,7 +2053,7 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
     }
     if (options->ConnDirectionStatistics &&
         load_stats_file("stats"PATH_SEPARATOR"conn-stats",
-                        "conn-stats-end", now, &contents) > 0) {
+                        "conn-bi-direct", now, &contents) > 0) {
       size_t pos = strlen(s);
       if (strlcpy(s + pos, contents, maxlen - strlen(s)) !=
           strlen(contents)) {

src/test/test.c

@@ -1175,8 +1175,7 @@ test_stats(void)
   rep_hist_note_or_conn_bytes(2, 400000, 30000, now + 10);
   rep_hist_note_or_conn_bytes(2, 400000, 30000, now + 15);
   s = rep_hist_format_conn_stats(now + 86400);
-  test_streq("conn-stats-end 2010-08-12 13:27:30 (86400 s)\n"
-             "conn-bi-direct 0,0,1,0\n", s);
+  test_streq("conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,1,0\n", s);
   tor_free(s);
 
   /* Stop collecting stats, add some bytes, and ensure we don't generate
@@ -1187,7 +1186,7 @@ test_stats(void)
   test_assert(!s);
 
   /* Re-start stats, add some bytes, reset stats, and see what history we
-   * get when observing no streams or bytes at all. */
+   * get when observing no bytes at all. */
   rep_hist_conn_stats_init(now);
   rep_hist_note_or_conn_bytes(1, 30000, 400000, now);
   rep_hist_note_or_conn_bytes(1, 30000, 400000, now + 5);
@@ -1195,8 +1194,7 @@ test_stats(void)
   rep_hist_note_or_conn_bytes(2, 400000, 30000, now + 15);
   rep_hist_reset_conn_stats(now);
   s = rep_hist_format_conn_stats(now + 86400);
-  test_streq("conn-stats-end 2010-08-12 13:27:30 (86400 s)\n"
-             "conn-bi-direct 0,0,0,0\n", s);
+  test_streq("conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,0,0\n", s);
 
  done:
   tor_free(s);