* Stop checking the entire AddressBook for each connection attempt
* Stop redundant peer time checks within the address book
* Stop calling `Instant::now` 3 times for each address book update
* Only get the time once each time an address book method is called
* Update outdated comment
* Use an OrderedMap to efficiently store address book peers
* Add address book order tests
* Add a `Duration32::from_days` constructor
Make it simpler to construct a `Duration32` representing a certain
number of days.
* Add `MetaAddr::was_not_recently_seen` method
A helper method to check if a peer was never seen before or if it was
last seen a long time ago. This will be one of the conditions to
consider a peer as unreachable.
* Add `MetaAddr::is_probably_unreachable` method
A helper method to check if a peer should be considered unreachable. It
is considered unreachable if recent connection attempts have failed and
it was not recently seen.
If a peer is considered unreachable, Zebra shouldn't attempt to connect
to it again.
* Do not keep trying to connect to unreachable peer
A peer is probably unreachable if it was last seen a long time ago and
if it's last connection attempt failed.
* Test `was_not_recently_seen`
Redo the calculation on arbitrary `MetaAddr`s.
* Test `is_probably_unreachable`
Redo the calculation on arbitrary `MetaAddr`s.
* Test if probably unreachable peers are ignored
Given an `AddressBook` with a list of arbitrary `MetaAddr`s, check that
none of the peers listed for a reconnection is probably unreachable.
* Rename unit test to improve clarity
Remove the double negative from the name.
Co-authored-by: teor <teor@riseup.net>
* Rename constant to `MAX_RECENT_PEER_AGE`
Make the purpose of the constant clearer.
Co-authored-by: teor <teor@riseup.net>
* Rename method to `last_seen_is_recent`
Remove the double negative from the name.
* Rename method to `is_probably_reachable`
Avoid having to negate the result of the method in security critical
filter.
* Move check into `is_ready_for_connection_attempt`
Make sure the check is used in any place that requires a peer that's
ready for a connection attempt.
* Improve test documention
Describe the goal of the test better.
Co-authored-by: teor <teor@riseup.net>
* Improve `is_probably_reachable` documentation
List the conditions as bullet points.
Co-authored-by: teor <teor@riseup.net>
* Document what happens when peers have no last seen time
Co-authored-by: teor <teor@riseup.net>
* Rename some methods and constants for clarity
Using the following commands:
```
fastmod '\bis_ready_for_attempt\b' is_ready_for_connection_attempt
# One instance required a tweak, because of the ASCII diagram.
fastmod '\bwas_recently_live\b' has_connection_recently_responded
fastmod '\bwas_recently_attempted\b' was_connection_recently_attempted
fastmod '\bwas_recently_failed\b' has_connection_recently_failed
fastmod '\bLIVE_PEER_DURATION\b' MIN_PEER_RECONNECTION_DELAY
```
* Use `Instant::elapsed` for conciseness
Instead of `Instant::now().saturating_duration_since`. They're both
equivalent, and `elapsed` only panics if the `Instant` is somehow
synthetically generated.
* Allow `Duration32` to be created in other crates
Export the `Duration32` from the `zebra_chain::serialization` module.
* Add some new `Duration32` constructors
Create some helper `const` constructors to make it easy to create
constant durations. Add methods to create a `Duration32` from seconds,
minutes and hours.
* Avoid gossiping unreachable peers
When sanitizing the list of peers to gossip, remove those that we
haven't seen in more than three hours.
* Test if unreachable addresses aren't gossiped
Create a property test with random addreses inserted into an
`AddressBook`, and verify that the sanitized list of addresses does not
contain any addresses considered unreachable.
* Test if new alternate address isn't gossipable
Create a new alternate peer, because that type of `MetaAddr` does not
have `last_response` or `untrusted_last_seen` times. Verify that the
peer is not considered gossipable.
* Test if local listener is gossipable
The `MetaAddr` representing the local peer's listening address should
always be considered gossipable.
* Test if gossiped peer recently seen is gossipable
Create a `MetaAddr` representing a gossiped peer that was reported to be
seen recently. Check that the peer is considered gossipable.
* Test peer reportedly last seen in the future
Create a `MetaAddr` representing a peer gossiped and reported to have
been last seen in a time that's in the future. Check that the peer is
considered gossipable, to check that the fallback calculation is working
as intended.
* Test gossiped peer reportedly seen long ago
Create a `MetaAddr` representing a gossiped peer that was reported to
last have been seen a long time ago. Check that the peer is not
considered gossipable.
* Test if just responded peer is gossipable
Create a `MetaAddr` representing a peer that has just responded and
check that it is considered gossipable.
* Test if recently responded peer is gossipable
Create a `MetaAddr` representing a peer that last responded within the
duration a peer is considered reachable. Verify that the peer is
considered gossipable.
* Test peer that responded long ago isn't gossipable
Create a `MetaAddr` representing a peer that last responded outside the
duration a peer is considered reachable. Verify that the peer is not
considered gossipable.