Merge remote-tracking branch 'dgoulet/ticket21980_031_01'

src/or/hs_common.c

@@ -9,6 +9,8 @@
  *        protocol.
  **/
 
+#define HS_COMMON_PRIVATE
+
 #include "or.h"
 
 #include "config.h"
@@ -50,6 +52,46 @@ hs_check_service_private_dir(const char *username, const char *path,
   return 0;
 }
 
+/** Get the default HS time period length in minutes from the consensus. */
+STATIC uint64_t
+get_time_period_length(void)
+{
+  int32_t time_period_length = networkstatus_get_param(NULL, "hsdir-interval",
+                                             HS_TIME_PERIOD_LENGTH_DEFAULT,
+                                             HS_TIME_PERIOD_LENGTH_MIN,
+                                             HS_TIME_PERIOD_LENGTH_MAX);
+  /* Make sure it's a positive value. */
+  tor_assert(time_period_length >= 0);
+  /* uint64_t will always be able to contain a int32_t */
+  return (uint64_t) time_period_length;
+}
+
+/** Get the HS time period number at time <b>now</b> */
+STATIC uint64_t
+get_time_period_num(time_t now)
+{
+  uint64_t time_period_num;
+  uint64_t time_period_length = get_time_period_length();
+  uint64_t minutes_since_epoch = now / 60;
+
+  /* Now subtract half a day to fit the prop224 time period schedule (see
+   * section [TIME-PERIODS]). */
+  tor_assert(minutes_since_epoch > HS_TIME_PERIOD_ROTATION_OFFSET);
+  minutes_since_epoch -= HS_TIME_PERIOD_ROTATION_OFFSET;
+
+  /* Calculate the time period */
+  time_period_num = minutes_since_epoch / time_period_length;
+  return time_period_num;
+}
+
+/** Get the number of the _upcoming_ HS time period, given that the current
+ *  time is <b>now</b>. */
+uint64_t
+hs_get_next_time_period_num(time_t now)
+{
+  return get_time_period_num(now) + 1;
+}
+
 /* Create a new rend_data_t for a specific given <b>version</b>.
  * Return a pointer to the newly allocated data structure. */
 static rend_data_t *

src/or/hs_common.h

@@ -40,6 +40,15 @@
 /* String prefix for the signature of ESTABLISH_INTRO */
 #define ESTABLISH_INTRO_SIG_PREFIX "Tor establish-intro cell v1"
 
+/* The default HS time period length */
+#define HS_TIME_PERIOD_LENGTH_DEFAULT 1440 /* 1440 minutes == one day */
+/* The minimum time period length as seen in prop224 section [TIME-PERIODS] */
+#define HS_TIME_PERIOD_LENGTH_MIN 30 /* minutes */
+/* The minimum time period length as seen in prop224 section [TIME-PERIODS] */
+#define HS_TIME_PERIOD_LENGTH_MAX (60 * 24 * 10) /* 10 days or 14400 minutes */
+/* The time period rotation offset as seen in prop224 section [TIME-PERIODS] */
+#define HS_TIME_PERIOD_ROTATION_OFFSET (12 * 60) /* minutes */
+
 int hs_check_service_private_dir(const char *username, const char *path,
                                  unsigned int dir_group_readable,
                                  unsigned int create);
@@ -60,5 +69,18 @@ const char *rend_data_get_desc_id(const rend_data_t *rend_data,
 const uint8_t *rend_data_get_pk_digest(const rend_data_t *rend_data,
                                        size_t *len_out);
 
+uint64_t hs_get_next_time_period_num(time_t now);
+
+#ifdef HS_COMMON_PRIVATE
+
+#ifdef TOR_UNIT_TESTS
+
+STATIC uint64_t get_time_period_length(void);
+STATIC uint64_t get_time_period_num(time_t now);
+
+#endif /* TOR_UNIT_TESTS */
+
+#endif /* HS_COMMON_PRIVATE */
+
 #endif /* TOR_HS_COMMON_H */