Merge branch 'tor-gitlab/mr/39'

9 files changed, 346 insertions, 255 deletions

diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
index 2f3c70365a..1d53e077d1 100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@ -105,6 +105,7 @@
 #include "feature/relay/routermode.h"
 #include "feature/rend/rendclient.h"
 #include "feature/rend/rendcommon.h"
+#include "feature/stats/connstats.h"
 #include "feature/stats/rephist.h"
 #include "feature/stats/bwhist.h"
 #include "lib/crypt_ops/crypto_util.h"
@@ -3362,11 +3363,11 @@ record_num_bytes_transferred_impl(connection_t *conn,
   if (!connection_is_rate_limited(conn))
     return;
 
+  const bool is_ipv6 = (conn->socket_family == AF_INET6);
   if (conn->type == CONN_TYPE_OR)
-    rep_hist_note_or_conn_bytes(conn->global_identifier, num_read,
-                                num_written, now);
+    conn_stats_note_or_conn_bytes(conn->global_identifier, num_read,
+                                  num_written, now, is_ipv6);
 
-  const bool is_ipv6 = (conn->socket_family == AF_INET6);
   if (num_read > 0) {
     bwhist_note_bytes_read(num_read, now, is_ipv6);
   }
diff --git a/src/core/mainloop/mainloop.c b/src/core/mainloop/mainloop.c
index e4e17f6b76..3bf9be566b 100644
--- a/src/core/mainloop/mainloop.c
+++ b/src/core/mainloop/mainloop.c
@@ -95,6 +95,7 @@
 #include "feature/rend/rendservice.h"
 #include "feature/stats/geoip_stats.h"
 #include "feature/stats/predict_ports.h"
+#include "feature/stats/connstats.h"
 #include "feature/stats/rephist.h"
 #include "lib/buf/buffers.h"
 #include "lib/crypt_ops/crypto_rand.h"
@@ -1950,7 +1951,7 @@ write_stats_file_callback(time_t now, const or_options_t *options)
       next_time_to_write_stats_files = next_write;
   }
   if (options->ConnDirectionStatistics) {
-    time_t next_write = rep_hist_conn_stats_write(now);
+    time_t next_write = conn_stats_save(now);
     if (next_write && next_write < next_time_to_write_stats_files)
       next_time_to_write_stats_files = next_write;
   }
diff --git a/src/feature/relay/relay_config.c b/src/feature/relay/relay_config.c
index bd1c1e8fe8..7cb7f2ccfd 100644
--- a/src/feature/relay/relay_config.c
+++ b/src/feature/relay/relay_config.c
@@ -36,6 +36,7 @@
 #include "feature/nodelist/nickname.h"
 #include "feature/stats/geoip_stats.h"
 #include "feature/stats/predict_ports.h"
+#include "feature/stats/connstats.h"
 #include "feature/stats/rephist.h"
 
 #include "feature/dirauth/authmode.h"
@@ -1307,7 +1308,7 @@ options_act_relay_stats(const or_options_t *old_options,
     }
     if ((!old_options || !old_options->ConnDirectionStatistics) &&
         options->ConnDirectionStatistics) {
-      rep_hist_conn_stats_init(now);
+      conn_stats_init(now);
     }
     if ((!old_options || !old_options->HiddenServiceStatistics) &&
         options->HiddenServiceStatistics) {
@@ -1337,7 +1338,7 @@ options_act_relay_stats(const or_options_t *old_options,
     rep_hist_exit_stats_term();
   if (old_options && old_options->ConnDirectionStatistics &&
       !options->ConnDirectionStatistics)
-    rep_hist_conn_stats_term();
+    conn_stats_terminate();
 
   return 0;
 }
diff --git a/src/feature/stats/connstats.c b/src/feature/stats/connstats.c
new file mode 100644
index 0000000000..f0c786efb3
--- /dev/null
+++ b/src/feature/stats/connstats.c
@@ -0,0 +1,283 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file connstats.c
+ * @brief Count bidirectional vs one-way connections.
+ *
+ * Connection statistics, use to track one-way and bidirectional connections.
+ *
+ * Note that this code counts concurrent connections in each
+ * BIDI_INTERVAL-second interval, not total connections.  It can tell you what
+ * fraction of connections are bidirectional at each time, not necessarily
+ * what number are bidirectional.
+ **/
+
+#include "orconfig.h"
+#include "core/or/or.h"
+#include "feature/stats/connstats.h"
+#include "app/config/config.h"
+
+/** Start of the current connection stats interval or 0 if we're not
+ * collecting connection statistics. */
+static time_t start_of_conn_stats_interval;
+
+/** Initialize connection stats. */
+void
+conn_stats_init(time_t now)
+{
+  start_of_conn_stats_interval = now;
+}
+
+/** Count connections on which we read and wrote less than this many bytes
+ * as "below threshold." */
+#define BIDI_THRESHOLD 20480
+
+/** Count connections that we read or wrote at least this factor as many
+ * bytes from/to than we wrote or read to/from as mostly reading or
+ * writing. */
+#define BIDI_FACTOR 10
+
+/** Interval length in seconds for considering read and written bytes for
+ * connection stats. */
+#define BIDI_INTERVAL 10
+
+/** Start of next BIDI_INTERVAL second interval. */
+static time_t bidi_next_interval = 0;
+
+/** A single grouped set of connection type counts. */
+typedef struct conn_counts_t {
+  /** Number of connections that we read and wrote less than BIDI_THRESHOLD
+   * bytes from/to in BIDI_INTERVAL seconds. */
+  uint32_t below_threshold;
+
+  /** Number of connections that we read at least BIDI_FACTOR times more
+   * bytes from than we wrote to in BIDI_INTERVAL seconds. */
+  uint32_t mostly_read;
+
+  /** Number of connections that we wrote at least BIDI_FACTOR times more
+   * bytes to than we read from in BIDI_INTERVAL seconds. */
+  uint32_t mostly_written;
+
+  /** Number of connections that we read and wrote at least BIDI_THRESHOLD
+   * bytes from/to, but not BIDI_FACTOR times more in either direction in
+   * BIDI_INTERVAL seconds. */
+  uint32_t both_read_and_written;
+} conn_counts_t ;
+
+/** A collection of connection counts, over all OR connections. */
+static conn_counts_t counts;
+/** A collection of connection counts, over IPv6 OR connections only. */
+static conn_counts_t counts_ipv6;
+
+/** Entry in a map from connection ID to the number of read and written
+ * bytes on this connection in a BIDI_INTERVAL second interval. */
+typedef struct bidi_map_entry_t {
+  HT_ENTRY(bidi_map_entry_t) node;
+  uint64_t conn_id; /**< Connection ID */
+  size_t read; /**< Number of read bytes */
+  size_t written; /**< Number of written bytes */
+  bool is_ipv6; /**< True if this is an IPv6 connection */
+} bidi_map_entry_t;
+
+/** Map of OR connections together with the number of read and written
+ * bytes in the current BIDI_INTERVAL second interval. */
+static HT_HEAD(bidimap, bidi_map_entry_t) bidi_map =
+     HT_INITIALIZER();
+
+/** Hashtable helper: return true if @a a and @a b have the same key. */
+static int
+bidi_map_ent_eq(const bidi_map_entry_t *a, const bidi_map_entry_t *b)
+{
+  return a->conn_id == b->conn_id;
+}
+
+/** Hashtable helper: compute a digest for the key of @a entry. */
+static unsigned
+bidi_map_ent_hash(const bidi_map_entry_t *entry)
+{
+  return (unsigned) entry->conn_id;
+}
+
+HT_PROTOTYPE(bidimap, bidi_map_entry_t, node, bidi_map_ent_hash,
+             bidi_map_ent_eq);
+HT_GENERATE2(bidimap, bidi_map_entry_t, node, bidi_map_ent_hash,
+             bidi_map_ent_eq, 0.6, tor_reallocarray_, tor_free_);
+
+/** Release all storage held in connstats.c */
+void
+conn_stats_free_all(void)
+{
+  bidi_map_entry_t **ptr, **next, *ent;
+  for (ptr = HT_START(bidimap, &bidi_map); ptr; ptr = next) {
+    ent = *ptr;
+    next = HT_NEXT_RMV(bidimap, &bidi_map, ptr);
+    tor_free(ent);
+  }
+  HT_CLEAR(bidimap, &bidi_map);
+}
+
+/** Reset counters for conn statistics. */
+void
+conn_stats_reset(time_t now)
+{
+  start_of_conn_stats_interval = now;
+  memset(&counts, 0, sizeof(counts));
+  memset(&counts_ipv6, 0, sizeof(counts_ipv6));
+  conn_stats_free_all();
+}
+
+/** Stop collecting connection stats in a way that we can re-start doing
+ * so in conn_stats_init(). */
+void
+conn_stats_terminate(void)
+{
+  conn_stats_reset(0);
+}
+
+/**
+ * Record a single entry @a ent in the counts structure @cnt.
+ */
+static void
+add_entry_to_count(conn_counts_t *cnt, const bidi_map_entry_t *ent)
+{
+  if (ent->read + ent->written < BIDI_THRESHOLD)
+    cnt->below_threshold++;
+  else if (ent->read >= ent->written * BIDI_FACTOR)
+    cnt->mostly_read++;
+  else if (ent->written >= ent->read * BIDI_FACTOR)
+    cnt->mostly_written++;
+  else
+    cnt->both_read_and_written++;
+}
+
+/**
+ * Count all the connection information we've received during the current
+ * period in 'bidimap', and store that information in the appropriate count
+ * structures.
+ **/
+static void
+collect_period_statistics(void)
+{
+  bidi_map_entry_t **ptr, **next, *ent;
+  for (ptr = HT_START(bidimap, &bidi_map); ptr; ptr = next) {
+    ent = *ptr;
+    add_entry_to_count(&counts, ent);
+    if (ent->is_ipv6)
+      add_entry_to_count(&counts_ipv6, ent);
+    next = HT_NEXT_RMV(bidimap, &bidi_map, ptr);
+    tor_free(ent);
+  }
+  log_info(LD_GENERAL, "%d below threshold, %d mostly read, "
+           "%d mostly written, %d both read and written.",
+           counts.below_threshold, counts.mostly_read, counts.mostly_written,
+           counts.both_read_and_written);
+}
+
+/** We read <b>num_read</b> bytes and wrote <b>num_written</b> from/to OR
+ * connection <b>conn_id</b> in second <b>when</b>. If this is the first
+ * observation in a new interval, sum up the last observations. Add bytes
+ * for this connection. */
+void
+conn_stats_note_or_conn_bytes(uint64_t conn_id, size_t num_read,
+                              size_t num_written, time_t when,
+                              bool is_ipv6)
+{
+  if (!start_of_conn_stats_interval)
+    return;
+  /* Initialize */
+  if (bidi_next_interval == 0)
+    bidi_next_interval = when + BIDI_INTERVAL;
+  /* Sum up last period's statistics */
+  if (when >= bidi_next_interval) {
+    collect_period_statistics();
+    while (when >= bidi_next_interval)
+      bidi_next_interval += BIDI_INTERVAL;
+  }
+  /* Add this connection's bytes. */
+  if (num_read > 0 || num_written > 0) {
+    bidi_map_entry_t *entry, lookup;
+    lookup.conn_id = conn_id;
+    entry = HT_FIND(bidimap, &bidi_map, &lookup);
+    if (entry) {
+      entry->written += num_written;
+      entry->read += num_read;
+      entry->is_ipv6 |= is_ipv6;
+    } else {
+      entry = tor_malloc_zero(sizeof(bidi_map_entry_t));
+      entry->conn_id = conn_id;
+      entry->written = num_written;
+      entry->read = num_read;
+      entry->is_ipv6 = is_ipv6;
+      HT_INSERT(bidimap, &bidi_map, entry);
+    }
+  }
+}
+
+/** Return a newly allocated string containing the connection statistics
+ * until <b>now</b>, or NULL if we're not collecting conn stats. Caller must
+ * ensure start_of_conn_stats_interval is in the past. */
+char *
+conn_stats_format(time_t now)
+{
+  char *result, written_at[ISO_TIME_LEN+1];
+
+  if (!start_of_conn_stats_interval)
+    return NULL; /* Not initialized. */
+
+  tor_assert(now >= start_of_conn_stats_interval);
+
+  format_iso_time(written_at, now);
+  tor_asprintf(&result,
+               "conn-bi-direct %s (%d s) "
+                    "%"PRIu32",%"PRIu32",%"PRIu32",%"PRIu32"\n"
+               "ipv6-conn-bi-direct %s (%d s) "
+                    "%"PRIu32",%"PRIu32",%"PRIu32",%"PRIu32"\n",
+               written_at,
+               (unsigned) (now - start_of_conn_stats_interval),
+               counts.below_threshold,
+               counts.mostly_read,
+               counts.mostly_written,
+               counts.both_read_and_written,
+               written_at,
+               (unsigned) (now - start_of_conn_stats_interval),
+               counts_ipv6.below_threshold,
+               counts_ipv6.mostly_read,
+               counts_ipv6.mostly_written,
+               counts_ipv6.both_read_and_written);
+
+  return result;
+}
+
+/** If 24 hours have passed since the beginning of the current conn stats
+ * period, write conn stats to $DATADIR/stats/conn-stats (possibly
+ * overwriting an existing file) and reset counters.  Return when we would
+ * next want to write conn stats or 0 if we never want to write. */
+time_t
+conn_stats_save(time_t now)
+{
+  char *str = NULL;
+
+  if (!start_of_conn_stats_interval)
+    return 0; /* Not initialized. */
+  if (start_of_conn_stats_interval + WRITE_STATS_INTERVAL > now)
+    goto done; /* Not ready to write */
+
+  /* Generate history string. */
+  str = conn_stats_format(now);
+
+  /* Reset counters. */
+  conn_stats_reset(now);
+
+  /* Try to write to disk. */
+  if (!check_or_create_data_subdir("stats")) {
+    write_to_data_subdir("stats", "conn-stats", str, "connection statistics");
+  }
+
+ done:
+  tor_free(str);
+  return start_of_conn_stats_interval + WRITE_STATS_INTERVAL;
+}
diff --git a/src/feature/stats/connstats.h b/src/feature/stats/connstats.h
new file mode 100644
index 0000000000..1a03d0748b
--- /dev/null
+++ b/src/feature/stats/connstats.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file connstats.h
+ * @brief Header for feature/stats/connstats.c
+ **/
+
+#ifndef TOR_FEATURE_STATS_CONNSTATS_H
+#define TOR_FEATURE_STATS_CONNSTATS_H
+
+void conn_stats_init(time_t now);
+void conn_stats_note_or_conn_bytes(uint64_t conn_id, size_t num_read,
+                                   size_t num_written, time_t when,
+                                   bool is_ipv6);
+void conn_stats_reset(time_t now);
+char *conn_stats_format(time_t now);
+time_t conn_stats_save(time_t now);
+void conn_stats_terminate(void);
+void conn_stats_free_all(void);
+
+#endif /* !defined(TOR_FEATURE_STATS_CONNSTATS_H) */
diff --git a/src/feature/stats/include.am b/src/feature/stats/include.am
index 32e760a08b..bc13882f4b 100644
--- a/src/feature/stats/include.am
+++ b/src/feature/stats/include.am
@@ -2,6 +2,7 @@
 # ADD_C_FILE: INSERT SOURCES HERE.
 LIBTOR_APP_A_SOURCES += 			\
 	src/feature/stats/bwhist.c		\
+	src/feature/stats/connstats.c		\
 	src/feature/stats/geoip_stats.c		\
 	src/feature/stats/rephist.c		\
 	src/feature/stats/predict_ports.c
@@ -9,6 +10,7 @@ LIBTOR_APP_A_SOURCES += 			\
 # ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/feature/stats/bwhist.h			\
+	src/feature/stats/connstats.h			\
 	src/feature/stats/geoip_stats.h			\
 	src/feature/stats/rephist.h			\
 	src/feature/stats/predict_ports.h
diff --git a/src/feature/stats/rephist.c b/src/feature/stats/rephist.c
index 6f409a46fc..b6730e1226 100644
--- a/src/feature/stats/rephist.c
+++ b/src/feature/stats/rephist.c
@@ -43,9 +43,6 @@
  * <li>Descriptor serving statistics, used by directory caches to track
  * how many descriptors they've served.
  *
- * <li>Connection statistics, used by relays to track one-way and
- * bidirectional connections.
- *
  * <li>Onion handshake statistics, used by relays to count how many
  * TAP and ntor handshakes they've handled.
  *
@@ -78,6 +75,7 @@
 #include "feature/nodelist/networkstatus.h"
 #include "feature/nodelist/nodelist.h"
 #include "feature/stats/predict_ports.h"
+#include "feature/stats/connstats.h"
 #include "feature/stats/rephist.h"
 #include "lib/container/order.h"
 #include "lib/crypt_ops/crypto_rand.h"
@@ -1648,223 +1646,6 @@ rep_hist_note_desc_served(const char * desc)
 
 /*** Connection statistics ***/
 
-/** Start of the current connection stats interval or 0 if we're not
- * collecting connection statistics. */
-static time_t start_of_conn_stats_interval;
-
-/** Initialize connection stats. */
-void
-rep_hist_conn_stats_init(time_t now)
-{
-  start_of_conn_stats_interval = now;
-}
-
-/* Count connections that we read and wrote less than these many bytes
- * from/to as below threshold. */
-#define BIDI_THRESHOLD 20480
-
-/* Count connections that we read or wrote at least this factor as many
- * bytes from/to than we wrote or read to/from as mostly reading or
- * writing. */
-#define BIDI_FACTOR 10
-
-/* Interval length in seconds for considering read and written bytes for
- * connection stats. */
-#define BIDI_INTERVAL 10
-
-/** Start of next BIDI_INTERVAL second interval. */
-static time_t bidi_next_interval = 0;
-
-/** Number of connections that we read and wrote less than BIDI_THRESHOLD
- * bytes from/to in BIDI_INTERVAL seconds. */
-static uint32_t below_threshold = 0;
-
-/** Number of connections that we read at least BIDI_FACTOR times more
- * bytes from than we wrote to in BIDI_INTERVAL seconds. */
-static uint32_t mostly_read = 0;
-
-/** Number of connections that we wrote at least BIDI_FACTOR times more
- * bytes to than we read from in BIDI_INTERVAL seconds. */
-static uint32_t mostly_written = 0;
-
-/** Number of connections that we read and wrote at least BIDI_THRESHOLD
- * bytes from/to, but not BIDI_FACTOR times more in either direction in
- * BIDI_INTERVAL seconds. */
-static uint32_t both_read_and_written = 0;
-
-/** Entry in a map from connection ID to the number of read and written
- * bytes on this connection in a BIDI_INTERVAL second interval. */
-typedef struct bidi_map_entry_t {
-  HT_ENTRY(bidi_map_entry_t) node;
-  uint64_t conn_id; /**< Connection ID */
-  size_t read; /**< Number of read bytes */
-  size_t written; /**< Number of written bytes */
-} bidi_map_entry_t;
-
-/** Map of OR connections together with the number of read and written
- * bytes in the current BIDI_INTERVAL second interval. */
-static HT_HEAD(bidimap, bidi_map_entry_t) bidi_map =
-     HT_INITIALIZER();
-
-static int
-bidi_map_ent_eq(const bidi_map_entry_t *a, const bidi_map_entry_t *b)
-{
-  return a->conn_id == b->conn_id;
-}
-
-/* DOCDOC bidi_map_ent_hash */
-static unsigned
-bidi_map_ent_hash(const bidi_map_entry_t *entry)
-{
-  return (unsigned) entry->conn_id;
-}
-
-HT_PROTOTYPE(bidimap, bidi_map_entry_t, node, bidi_map_ent_hash,
-             bidi_map_ent_eq);
-HT_GENERATE2(bidimap, bidi_map_entry_t, node, bidi_map_ent_hash,
-             bidi_map_ent_eq, 0.6, tor_reallocarray_, tor_free_);
-
-/* DOCDOC bidi_map_free */
-static void
-bidi_map_free_all(void)
-{
-  bidi_map_entry_t **ptr, **next, *ent;
-  for (ptr = HT_START(bidimap, &bidi_map); ptr; ptr = next) {
-    ent = *ptr;
-    next = HT_NEXT_RMV(bidimap, &bidi_map, ptr);
-    tor_free(ent);
-  }
-  HT_CLEAR(bidimap, &bidi_map);
-}
-
-/** Reset counters for conn statistics. */
-void
-rep_hist_reset_conn_stats(time_t now)
-{
-  start_of_conn_stats_interval = now;
-  below_threshold = 0;
-  mostly_read = 0;
-  mostly_written = 0;
-  both_read_and_written = 0;
-  bidi_map_free_all();
-}
-
-/** Stop collecting connection stats in a way that we can re-start doing
- * so in rep_hist_conn_stats_init(). */
-void
-rep_hist_conn_stats_term(void)
-{
-  rep_hist_reset_conn_stats(0);
-}
-
-/** We read <b>num_read</b> bytes and wrote <b>num_written</b> from/to OR
- * connection <b>conn_id</b> in second <b>when</b>. If this is the first
- * observation in a new interval, sum up the last observations. Add bytes
- * for this connection. */
-void
-rep_hist_note_or_conn_bytes(uint64_t conn_id, size_t num_read,
-                            size_t num_written, time_t when)
-{
-  if (!start_of_conn_stats_interval)
-    return;
-  /* Initialize */
-  if (bidi_next_interval == 0)
-    bidi_next_interval = when + BIDI_INTERVAL;
-  /* Sum up last period's statistics */
-  if (when >= bidi_next_interval) {
-    bidi_map_entry_t **ptr, **next, *ent;
-    for (ptr = HT_START(bidimap, &bidi_map); ptr; ptr = next) {
-      ent = *ptr;
-      if (ent->read + ent->written < BIDI_THRESHOLD)
-        below_threshold++;
-      else if (ent->read >= ent->written * BIDI_FACTOR)
-        mostly_read++;
-      else if (ent->written >= ent->read * BIDI_FACTOR)
-        mostly_written++;
-      else
-        both_read_and_written++;
-      next = HT_NEXT_RMV(bidimap, &bidi_map, ptr);
-      tor_free(ent);
-    }
-    while (when >= bidi_next_interval)
-      bidi_next_interval += BIDI_INTERVAL;
-    log_info(LD_GENERAL, "%d below threshold, %d mostly read, "
-             "%d mostly written, %d both read and written.",
-             below_threshold, mostly_read, mostly_written,
-             both_read_and_written);
-  }
-  /* Add this connection's bytes. */
-  if (num_read > 0 || num_written > 0) {
-    bidi_map_entry_t *entry, lookup;
-    lookup.conn_id = conn_id;
-    entry = HT_FIND(bidimap, &bidi_map, &lookup);
-    if (entry) {
-      entry->written += num_written;
-      entry->read += num_read;
-    } else {
-      entry = tor_malloc_zero(sizeof(bidi_map_entry_t));
-      entry->conn_id = conn_id;
-      entry->written = num_written;
-      entry->read = num_read;
-      HT_INSERT(bidimap, &bidi_map, entry);
-    }
-  }
-}
-
-/** Return a newly allocated string containing the connection statistics
- * until <b>now</b>, or NULL if we're not collecting conn stats. Caller must
- * ensure start_of_conn_stats_interval is in the past. */
-char *
-rep_hist_format_conn_stats(time_t now)
-{
-  char *result, written[ISO_TIME_LEN+1];
-
-  if (!start_of_conn_stats_interval)
-    return NULL; /* Not initialized. */
-
-  tor_assert(now >= start_of_conn_stats_interval);
-
-  format_iso_time(written, now);
-  tor_asprintf(&result, "conn-bi-direct %s (%d s) %d,%d,%d,%d\n",
-               written,
-               (unsigned) (now - start_of_conn_stats_interval),
-               below_threshold,
-               mostly_read,
-               mostly_written,
-               both_read_and_written);
-  return result;
-}
-
-/** If 24 hours have passed since the beginning of the current conn stats
- * period, write conn stats to $DATADIR/stats/conn-stats (possibly
- * overwriting an existing file) and reset counters.  Return when we would
- * next want to write conn stats or 0 if we never want to write. */
-time_t
-rep_hist_conn_stats_write(time_t now)
-{
-  char *str = NULL;
-
-  if (!start_of_conn_stats_interval)
-    return 0; /* Not initialized. */
-  if (start_of_conn_stats_interval + WRITE_STATS_INTERVAL > now)
-    goto done; /* Not ready to write */
-
-  /* Generate history string. */
-  str = rep_hist_format_conn_stats(now);
-
-  /* Reset counters. */
-  rep_hist_reset_conn_stats(now);
-
-  /* Try to write to disk. */
-  if (!check_or_create_data_subdir("stats")) {
-    write_to_data_subdir("stats", "conn-stats", str, "connection statistics");
-  }
-
- done:
-  tor_free(str);
-  return start_of_conn_stats_interval + WRITE_STATS_INTERVAL;
-}
-
 /** Internal statistics to track how many requests of each type of
  * handshake we've received, and how many we've assigned to cpuworkers.
  * Useful for seeing trends in cpu load.
@@ -2360,7 +2141,7 @@ rep_hist_free_all(void)
   tor_free(exit_bytes_written);
   tor_free(exit_streams);
   predicted_ports_free_all();
-  bidi_map_free_all();
+  conn_stats_free_all();
 
   if (circuits_for_buffer_stats) {
     SMARTLIST_FOREACH(circuits_for_buffer_stats, circ_buffer_stats_t *, s,
diff --git a/src/feature/stats/rephist.h b/src/feature/stats/rephist.h
index cdedfdca63..c9ebc5c328 100644
--- a/src/feature/stats/rephist.h
+++ b/src/feature/stats/rephist.h
@@ -56,14 +56,6 @@ void rep_hist_note_desc_served(const char * desc);
 void rep_hist_desc_stats_term(void);
 time_t rep_hist_desc_stats_write(time_t now);
 
-void rep_hist_conn_stats_init(time_t now);
-void rep_hist_note_or_conn_bytes(uint64_t conn_id, size_t num_read,
-                                 size_t num_written, time_t when);
-void rep_hist_reset_conn_stats(time_t now);
-char *rep_hist_format_conn_stats(time_t now);
-time_t rep_hist_conn_stats_write(time_t now);
-void rep_hist_conn_stats_term(void);
-
 void rep_hist_note_circuit_handshake_requested(uint16_t type);
 void rep_hist_note_circuit_handshake_assigned(uint16_t type);
 void rep_hist_log_circuit_handshake_stats(time_t now);
diff --git a/src/test/test_stats.c b/src/test/test_stats.c
index 291473ebc9..f0715c2e45 100644
--- a/src/test/test_stats.c
+++ b/src/test/test_stats.c
@@ -39,6 +39,7 @@
 #include "test/test.h"
 #include "core/mainloop/mainloop.h"
 #include "lib/memarea/memarea.h"
+#include "feature/stats/connstats.h"
 #include "feature/stats/rephist.h"
 #include "app/config/statefile.h"
 
@@ -111,37 +112,41 @@ test_stats(void *arg)
 
   /* Continue with testing connection statistics; we shouldn't collect
    * conn stats without initializing them. */
-  rep_hist_note_or_conn_bytes(1, 20, 400, now);
-  s = rep_hist_format_conn_stats(now + 86400);
+  conn_stats_note_or_conn_bytes(1, 20, 400, now, false);
+  s = conn_stats_format(now + 86400);
   tt_ptr_op(s, OP_EQ, NULL);
 
   /* Initialize stats, note bytes, and generate history string. */
-  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);
-  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);
-  tt_str_op("conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,1,0\n",OP_EQ, s);
+  conn_stats_init(now);
+  conn_stats_note_or_conn_bytes(1, 30000, 400000, now, false);
+  conn_stats_note_or_conn_bytes(1, 30000, 400000, now + 5, false);
+  conn_stats_note_or_conn_bytes(2, 400000, 30000, now + 10, true);
+  conn_stats_note_or_conn_bytes(2, 400000, 30000, now + 15, true);
+  s = conn_stats_format(now + 86400);
+  tt_str_op("conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,1,0\n"
+            "ipv6-conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,0,0\n",
+            OP_EQ, s);
   tor_free(s);
 
   /* Stop collecting stats, add some bytes, and ensure we don't generate
    * a history string. */
-  rep_hist_conn_stats_term();
-  rep_hist_note_or_conn_bytes(2, 400000, 30000, now + 15);
-  s = rep_hist_format_conn_stats(now + 86400);
+  conn_stats_terminate();
+  conn_stats_note_or_conn_bytes(2, 400000, 30000, now + 15, true);
+  s = conn_stats_format(now + 86400);
   tt_ptr_op(s, OP_EQ, NULL);
 
   /* Re-start stats, add some bytes, reset stats, and see what history we
    * 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);
-  rep_hist_note_or_conn_bytes(2, 400000, 30000, now + 10);
-  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);
-  tt_str_op("conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,0,0\n",OP_EQ, s);
+  conn_stats_init(now);
+  conn_stats_note_or_conn_bytes(1, 30000, 400000, now, false);
+  conn_stats_note_or_conn_bytes(1, 30000, 400000, now + 5, false);
+  conn_stats_note_or_conn_bytes(2, 400000, 30000, now + 10, true);
+  conn_stats_note_or_conn_bytes(2, 400000, 30000, now + 15, true);
+  conn_stats_reset(now);
+  s = conn_stats_format(now + 86400);
+  tt_str_op("conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,0,0\n"
+            "ipv6-conn-bi-direct 2010-08-12 13:27:30 (86400 s) 0,0,0,0\n",
+            OP_EQ, s);
   tor_free(s);
 
   /* Continue with testing buffer statistics; we shouldn't collect buffer