prop224: Refactor hs_get_time_period_num() to not use absolute time.

Instead use the SRV protocol duration to calculate the rotation offset
that was previously hardcoded to 12 hours.
This commit is contained in:
George Kadianakis 2017-07-24 13:31:17 +03:00 committed by Nick Mathewson
parent 2cd5f9a2fc
commit cf58451a8b
2 changed files with 9 additions and 6 deletions

View File

@ -196,13 +196,18 @@ uint64_t
hs_get_time_period_num(time_t now)
{
uint64_t time_period_num;
/* Start by calculating minutes since the epoch */
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;
/* Apply the rotation offset as specified by prop224 (section
* [TIME-PERIODS]), so that new time periods synchronize nicely with SRV
* publication */
unsigned int time_period_rotation_offset = sr_state_get_phase_duration();
time_period_rotation_offset /= 60; /* go from seconds to minutes */
tor_assert(minutes_since_epoch > time_period_rotation_offset);
minutes_since_epoch -= time_period_rotation_offset;
/* Calculate the time period */
time_period_num = minutes_since_epoch / time_period_length;

View File

@ -52,8 +52,6 @@
#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 */
/* Prefix of the onion address checksum. */
#define HS_SERVICE_ADDR_CHECKSUM_PREFIX ".onion checksum"