Prior to AMP, there could only be one HTLC set. Now that there can be
multiple, we introduce the inherent risk that we might be persisting a
settle/accept of the wrong HTLC set. To migitigate this risk, we add a
check to assert that an invoice can only be transitioned into an
Accepted or Settled state if the specified HTLC set is non-empty, i.e.
has accepted HTLCs.
To do this check, we unroll the loops in UpdateInvoice to first process
any added or canceled HTLCs. This ensures that the set of accepted HTLCs
is up-to-date when we got to transition the invoice into a new state, at
which point we can accurately check that the HTLC set is non-empty.
Previously this sort of check wasn't possible because a newly added HTLC
wouldn't be populated on the invoice when going to call
updateInvoiceState.
Once the invoice-level transition checks have completed, we complete a
final pass to move the HTLCs into their final states and recompute the
amount paid.
With this refactor, it is now possible to make stronger assertions
about the invoice and the state transitions being made by the
invoiceregistry before those changes are ultimately persisted.
Similarly as with kvdb.View this commits adds a reset closure to the
kvdb.Update call in order to be able to reset external state if the
underlying db backend needs to retry the transaction.
This commit adds a reset() closure to the kvdb.View function which will
be called before each retry (including the first) of the view
transaction. The reset() closure can be used to reset external state
(eg slices or maps) where the view closure puts intermediate results.
This commit extends channeldb with the DeleteInvoices call which is when
passed a slice of delete references will attempt to delete the invoices
pointed to by the references and also clean up all our invoice indexes.
This commit adds channeldb.ScanInvoices to scan through all invoices in
the database. The new call will also replace the already existing
channeldb.FetchAllInvoicesWithPaymentHash call in preparation to collect
invoices we'd like to delete and watch for expiry in one scan in later
commits.
Avoids indexing the all-zeros pay addr, since it is still in use by
legacy keysend. Without this, the pay addr index will reject all but the
first keysend since they will be detected as duplicates within the set
id index.
We now use the same method of pagination for invoices and payments.
Rather than duplicate logic across calls, we add a pagnator struct
which can have query specific logic plugged into it. This commit also
addresses an existing issue where a reverse query for invoices with an
offset larger than our last offset would not return any invoices. We
update this behaviour to act more like c.Seek and just start from the
last entry. This behaviour change is covered by a unit test that
previously checked for the lack of invoices.
Previously it wasn't possible to store a preimage in the invoice
database and signal that a payment should not be settled right away. The
only way to hold a payment was to insert the magic UnknownPreimage value
in the invoice database. This commit introduces a distinct flag to
signal that an invoice is a hold invoice and thereby allows the preimage
to be present in the database already.
Preparation for (key send) hodl invoices for which we already know the
preimage.
In this commit, we migrate all the code in `channeldb` to only reference
the new `kvdb` package rather than `bbolt` directly.
In many instances, we need to add two version to fetch a bucket as both
read and write when needed. As an example, we add a new
`fetchChanBucketRw` function. This function is identical to
`fetchChanBucket`, but it will be used to fetch the main channel bucket
for all _write_ transactions. We need a new method as you can pass a
write transaction where a read is accepted, but not the other way around
due to the stronger typing of the new `kvdb` package.
This commit removes channeldb.FetchAllInvoices and changes tests such
that expectation sets are prepared in the test case instead of selected
from the DB.
This commit adds handling code for the key send custom record. If this
record is present and its hash matches the payment hash, invoice
registry will insert a new invoice into the database "just in time". The
subsequent settle flow is unchanged. The newly inserted invoice is
picked up and settled. Notifications will be broadcast as usual.
This field isn't optional. It was introduced in
5ed31b1030 which was part of release
0.4.0. This release contained breaking database changes, so it is safe
to assume that from there on the field is always populated.
If there would still be empty payment request fields in the wild, users
would also experience issues with ListInvoices. ListInvoices decodes the
payment request.
This commits builds on top of PR #3694 to further clarify invoice
state by defining pending invoices as the ones which are not
settled or canceled. Automatic cancellation of expired invoices
makes this possbile. While this change only directly affects
ChannelDB, users of the listinvoices RPC will receive actual
pending invoices when pending_only flag is set.
This commit adds InvoiceExpryWatcher which is a separate class that
receives new invoices (and existing ones upon restart) from InvoiceRegistry
and actively watches their expiry. When an invoice is expired
InvoiceExpiryWatcher will call into InvoiceRegistry to cancel the
invoice and by that notify all subscribers about the state change.
Previously the cancel and add actions were combined in a single map.
Nil values implictly signaled cancel actions. This wasn't very obvious.
Furthermore this split prepares for processing the adds and cancels
separately, which is more efficient if there are already two maps.
This commit moves the update code into its own function as a preparation
for extending the logic further for mpp.
In order to make this change cleanly, structured result codes are
introduced. This also prepares for a future htlc notifier rpc hook that
reports htlc settle decisions to external applications.
Furthermore the awkward use of errNoUpdate as a way to signal no update
is removed.
This commit restructures an invoice's ContractTerms to better encompass
the restrictions placed on settling. For instance, the final ctlv delta
and invoice expiry are moved from the main invoice body (where
additional metadata is stored). Additionally, it moves the State field
outside of the terms since it is rather metadata about the invoice
instead of any terms offered to the sender in the payment request.
Previously the invoice registry wasn't aware of replayed htlcs. This was
dealt with by keeping the invoice accept/settle logic idempotent, so
that a replay wouldn't have an effect.
This mechanism has two limitations:
1. No accurate tracking of the total amount paid to an invoice. The total
amount couldn't just be increased with every htlc received, because it
could be a replay which would lead to counting the htlc amount multiple
times. Therefore the total amount was set to the amount of the first
htlc that was received, even though there may have been multiple htlcs
paying to the invoice.
2. Impossible to check htlc expiry consistently for hodl invoices. When
an htlc is new, its expiry needs to be checked against the invoice cltv
delta. But for a replay, that check must be skipped. The htlc was
accepted in time, the invoice was moved to the accepted state and a
replay some blocks later shouldn't lead to that htlc being cancelled.
Because the invoice registry couldn't recognize replays, it stopped
checking htlc expiry heights when the invoice reached the accepted
state. This prevents hold htlcs from being cancelled after a restart.
But unfortunately this also caused additional htlcs to be accepted on an
already accepted invoice without their expiry being checked.
In this commit, the invoice registry starts to persistently track htlcs
so that replays can be recognized. For replays, an htlc resolution
action is returned early. This fixes both limitations mentioned above.
