When we handle an inbound `channel_reestablish` from our peers it
generally doesn't change any state and thus doesn't need a
`ChannelManager` persistence. Here we avoid said persistence where
possible.
If we receive a `ChannelUpdate` message which was invalid, it can
cause us to force-close the channel, which should result in a
`ChannelManager` persistence, though its not critical to do so.
When a peer connects and we send some `channel_reestablish`
messages or create a `per_peer_state` entry there's really no
reason to need to persist the `ChannelManager`. None of the
possible actions we take immediately result in a change to the
persisted contents of a `ChannelManager`, only the peer's later
`channel_reestablish` message does.
Many channel related messages don't actually change the channel
state in a way that changes the persisted channel. For example,
an `update_add_htlc` or `update_fail_htlc` message simply adds the
change to a queue, changing the channel state when we receive a
`commitment_signed` message.
In these cases there's really no reason to wake the background
processor at all - there's no response message and there's no state
update. However, note that if we close the channel we should
persist the `ChannelManager`. If we send an error message without
closing the channel, we should wake the background processor
without persisting.
Here we move to the appropriate `NotifyOption` on some of the
simpler channel message handlers.
As we now signal events-available from persistence-needed
separately, the `NotifyOption` enum should include a separate
variant for events-but-no-persistence, which we add here.
Currently, when a ChannelManager generates a notification for the
background processor, any pending events are handled and the
ChannelManager is always re-persisted.
Many channel related messages don't actually change the channel
state in a way that changes the persisted channel. For example,
an `update_add_htlc` or `update_fail_htlc` message simply adds the
change to a queue, changing the channel state when we receive a
`commitment_signed` message.
In these cases we shouldn't be re-persisting the ChannelManager as
it hasn't changed (persisted) state at all. In anticipation of
doing so in the next few commits, here we make the public API
handle the two concepts (somewhat) separately. The notification
still goes out via a single waker, however whether or not to
persist is now handled via a separate atomic bool.
Prior to any actions which may generate a `ChannelMonitorUpdate`,
and in general after startup,
`ChannelManager::process_background_events` must be called. This is
mostly accomplished by doing so on taking the
`total_consistency_lock` via the `PersistenceNotifierGuard`. In
order to skip this call in block connection logic, the
`PersistenceNotifierGuard::optionally_notify` constructor did not
call the `process_background_events` method.
However, this is very easy to misuse - `optionally_notify` does not
convey to the reader that they need to call
`process_background_events` at all.
Here we fix this by adding a separate
`optionally_notify_skipping_background_events` method, making the
requirements much clearer to callers.
Long ago, for reasons lost to the ages, the
`PersistenceNotifierGuard::optionally_notify` constructor didn't
take a `ChannelManager` reference, but rather explicit references
to the fields of it that it needs.
This is cumbersome and useless, so we fix it here.
In the next commit, we separate `ChannelManager`'s concept of
waking a listener to both be persisted and to allow the user to
handle events. Here we rename the future-fetching method in
anticipation of this split.
We introduce the `ChannelPhase` enum which will contain the different
channel structs wrapped by each of its variants so that we can place
these within a single `channel_by_id` map in `peer_state` in the
following commits. This will reduce the number of map lookup operations
we need to do in `ChannelManager`'s various methods. It will also make
certain channel counting logic easier to reason about with less risk of
forgetting to modify logic when new channels structs are introduced for
V2 channel establishment.
Replace a constant three retry attempts for BOLT 12 invoice payments
with a retry strategy specified when creating a pending outbound
payment. This is configured by users in a later commit when constructing
an InvoiceRequest or a Refund.
An upcoming commit requires serializing Retry, so use a type with a
fixed byte length. Otherwise, using eight bytes to serialize a usize
would fail to read on 32-bit machines.
Add a send_payment_for_bolt12_invoice method to OutboundPayments for
initiating payment of a BOLT 12 invoice. This will be called from an
OffersMessageHandler, after which any retries are handled using the
Retryable logic.
Consolidate the creation and insertion of onion_session_privs to the
PendingOutboundPayment::Retryable arm. In an upcoming commit, this
method will be reused for an initial BOLT 12 invoice payment. However,
onion_session_privs are created using a different helper.
When a BOLT 12 invoice has been received, a payment attempt is made and
any errors result in abandoning the PendingOutboundPayment. This results
in generating at PaymentFailed event, which has a PaymentHash. Thus,
when receiving an invoice, transition from AwaitingInvoice to a new
InvoiceReceived state, the latter of which contains a PaymentHash such
the abandon_payment helper can still be used.
When a BOLT 12 invoice has been requested, in order to guarantee
invoice payment idempotency the future payment needs to be tracked. Add
an AwaitingInvoice variant to PendingOutboundPayment such that only
requested invoices are paid only once. Timeout after a few timer ticks
if a request has not been received.
Firstly, we switch our BP over to use `FilesystemStore`, which also gives us test
coverage and ensures the compatibility.
Then, we remove the superseded `KVStorePersister` trait and
the `FilesystemPersister` code.
We upstream the `KVStore` interface trait from LDK Node, which will
replace `KVStorePersister` in the coming commits.
Besides persistence, `KVStore` implementations will also offer to `list`
keys present in a given `namespace` and `read` the stored values.
When an invoice is requested but either receives an error or never
receives a response, surface an event to indicate to the user that the
corresponding future payment has failed.
