Module hsdir_params

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Available on crate feature hs-common only.

Expand description

Compute which time period and shared random value from a consensus to use at any given time.

This is, unfortunately, a bit complex. It works as follows:

The current time period is the one that contains the valid-after time for the consensus…
- but to compute the time period interval, you need to look at the consensus parameters,
- and to compute the time period offset, you need to know the consensus voting interval.
The SRV for any given time period is the one that that was the most recent at the start of the time period…
- but to know when an SRV was most recent, you need to read a timestamp from it that won’t be there until proposal 342 is implemented…
- and until then, you have to compute the start of the UTC day when the consensus became valid.

This module could conceivably be part of tor-netdoc, but it seems better to make it part of tor-netdir: this is where we put our complexity.

Structs§

ONE_DAY 🔒: One day.
VOTING_PERIODS_IN_OFFSET 🔒: By how many voting periods do we offset the beginning of our first time period from the epoch?
VOTING_PERIODS_IN_SRV_ROUND 🔒: How many voting periods make up an entire round of the shared random value commit-and-reveal protocol?

disaster_params 🔒: Compute ring parameters using a Disaster SRV for this period.
disaster_srv 🔒: Compute the “Disaster SRV” for a given time period.
extract_srvs 🔒: Return every SRV from a consensus, along with a duration over which it is most recent SRV.
find_params_for_time 🔒: Given a list of SrvInfo, return an HsRingParams instance for a given time period, if possible.
find_srv_for_time 🔒: Given a list of SrvInfo, return the SrvInfo (if any) that is the most recent SRV at when.
srv_interval 🔒: Return the length of time for which a single SRV value is valid.
start_of_day_containing 🔒: Return the length of the voting period in the consensus.

SrvInfo 🔒: Helper type: A SharedRandVal, and the time range over which it is the most recent.