With the introduction of the WatchtowerClient RPC subserver, the lnd
configuration flag to specify private watchtowers for the client is no
longer needed and can lead to confusion upon users. Therefore, we remove
the flag completely, and only rely on the watchtower client being active
through a new --wtclient.active flag.
We do this as a convenience for WatchtowerClient users so that they do
not need to re-add towers upon restarts. We ensure not to re-add towers
that have been previously removed by determining whether it has any
lingering active sessions.
In this commit, we extend the wtclient.Client interface with the
following methods:
* AddTower
* RemoveTower
* RegisteredTowers
* LookupTower
* Stats
Care has been taken to ensure that any in-memory state updates are
_only_ performed after a successful database update.
These methods are currently unused, but they serve as a dependency for
the upcoming WatchtowerClient RPC subserver.
These operations are currently unused, but will be integrated into the
TowerClient at a later point as future preparation for the
WatchtowerClient RPC subserver, which will allow users to add, remove,
and list the watchtowers currntly in use.
This currently takes O(N) time as there does not exist an index of
active client sessions for each watchtower within the client's database.
This index is likely to be added in the future.
This commit specifies two bbolt options when opening the underlying
channel and watchtower databases so that there is reduced heap
pressure in case the bbolt database has a lot of free pages in the
B+ tree.
Modifies the bbolt and mock tower databases to only accept blobs that
are the expected size of the session's blob type. This prevents resource
exhaustion attacks where a client may provide disproportionately large
encrypted blob, even though all supported blob types are of fixed-size.
This commit modifies the client's filtering when selecting from existing
sessions. The new logic compares the configured TxPolicy with the
TxPolicy of the candidate sessions, which has the effect of ignoring
operational parameters such as MaxUpdates. Prior, changing MaxUpdates
would cause the client to request a new session even if it had perfectly
good slots available in a policy with an equal TxPolicy.
This commit splits out the parameters that shape the justice transaction
into their own struct, which then embedded within the overarching
wtpolicy.Policy which may have additional parameters describing
operation of the session.
This is done as a preliminary step to support comparison of sessions
based on matching TxPolicy configurations. This prevents otherwise
identical Policies from being counted as different if operational
parameters like MaxUpdates differ, even if it has no material difference
to the justice transaction.
This commit fixes a bug that would cause us to request more sessions
that needed from the session negotiator. With the current stat ticker,
we'd ask the negotiator for a new session every 30s if session
session negotiation did not return before printing the stats. Now we'll
avoid requesting to sessions by jumping back into the select loop.
This commit adds persisted status bit-field to ClientSessions, that can
be used to modify behavior of their handling in the client. Currently,
only a default CSessionActive status is defined. However, the intention
is that this could later be used to signal that a session is abandoned
without needing to perform a db migration to add the field. As we move
forward with testing, this will likely be useful if a session gets
borked and we need a simple method of the client to temporarily ignore
certain sessions.
The field may be useful in signaling other types of status changes,
though this was the primary motivation that warranted the addition.
Now that the committed and acked updates are persisted across restarts,
we will use them to filter out duplicate commit heights presented by the
client.
