When we landed the initial in-`ChannelManager` payment retries, we
stored the `RouteParameters` in the payment info, and then re-use
it as-is for new payments. `RouteParameters` is intended to store
the information specific to the *route*, `PaymentParameters` exists
to store information specific to a payment.
Worse, because we don't recalculate the amount stored in the
`RouteParameters` before fetching a new route with it, we end up
attempting to retry the full payment amount, rather than only the
failed part.
This issue brought to you by having redundant data in
datastructures, part 5,001.
The documentation for `Retry` is very clear that it counts the
number of failed paths, not discrete retries. When we added
retries internally in `ChannelManager`, we switched to counting
the number if discrete retries, even if multiple paths failed and
were replace with multiple MPP HTLCs.
Because we are now rewriting retries, we take this opportunity to
reduce the places where retries are analyzed, specifically a good
chunk of code is removed from `pay_internal`.
Because we now retry multiple failed paths with one single retry,
we keep the new behavior, updating the docs on `Retry` to describe
the new behavior.
`TestRouter` allows us to simply select the `Route` that will be
returned in the next `find_route` call, but it does so without any
checking of what was *requested* for the call. This makes it a
somewhat dubious test utility as it very helpfully ensures we
ignore errors in the routes we're looking for.
Instead, we require users of `TestRouter` pass a `RouteParameters`
to `expect_find_route`, which we compare against the requested
parameters passed to `find_route`.
`PaymentParams` is all about the parameters for a payment, i.e. the
parameters which are static across all the paths of a paymet.
`RouteParameters` is about the information specific to a given
`Route` (i.e. a set of paths, among multiple potential sets of
paths for a payment). The CLTV delta thus doesn't belong in
`RouterParameters` but instead in `PaymentParameters`.
Worse, because `RouteParameters` is built from the information in
the last hops of a `Route`, when we deliberately inflate the CLTV
delta in path-finding, retries of the payment will have the final
CLTV delta double-inflated as it inflates starting from the final
CLTV delta used in the last attempt.
When we calculate the `final_cltv_expiry_delta` to put in the
`RouteParameters` returned via events after a payment failure, we
should re-use the new one in the `PaymentParameters`, rather than
the one that was in the route itself.
`PaymentParams` is all about the parameters for a payment, i.e. the
parameters which are static across all the paths of a paymet.
`RouteParameters` is about the information specific to a given
`Route` (i.e. a set of paths, among multiple potential sets of
paths for a payment). The CLTV delta thus doesn't belong in
`RouterParameters` but instead in `PaymentParameters`.
Worse, because `RouteParameters` is built from the information in
the last hops of a `Route`, when we deliberately inflate the CLTV
delta in path-finding, retries of the payment will have the final
CLTV delta double-inflated as it inflates starting from the final
CLTV delta used in the last attempt.
By moving the CLTV delta to `PaymentParameters` we avoid this
issue, leaving only the sought amount in the `RouteParameters`.
As of now the `Confirm::get_relevant_txids()` docs state that it won't
return any transactions for which we hadn't previously seen a
confirmation. To align its functionality a bit more with the docs, at
least for `ChannelManager`, we only return values for which we had
registered a confirmation block hash before.
`test_duplicate_payment_hash_one_failure_one_success` currently
fails if the "wrong" HTLC is picked to be claimed. Given the HTLCs
are identical, there's no way to figure out which we should claim.
The test instead relies on a magic value - the first one is the
right one....unless we change our CSPRNG implementation. When we
try to do so, the test randomly fails.
Here we change one HTLC to a lower amount so we can figure out
which transaction to broadcast to make the test robust against
CSPRNG changes.
FailureCode is used to specify which error code and data to send
to peers when failing back an HTLC.
ChannelManager::fail_htlc_backwards_with_reason
allows a user to specify the error code and
corresponding data to send to peers when failing back an HTLC.
This function is mentioned in Event::PaymentClaimable docs.
ChannelManager::get_htlc_fail_reason_from_failure_code was also
added to assist with this function.
It's not ideal to do all this computation while the lock is held. We also want
to decode the failure *before* taking the lock, so we can store the failed scid
in the relevant outbound for retry in the next commit(s).
Adds two new payment `Method`s for identifying payments with custom
`min_final_cltv_expiry_delta` as payments with LDK or user payment
hashes.
The `min_final_cltv_expiry_delta` value is packed into the first 2
bytes of the expiry timestamp in the payment secret metadata.
All utility functions for invoice construction will now also accept an
Option<>al `min_final_cltv_expiry_delta` which is useful for things like
swaps etc. The `min_final_cltv_expiry_delta` will default back to
`MIN_FINAL_CLTV_EXPIRY_DELTA` if `None` is provided.
This matches the spec and helps avoid any confusion around
naming. We're also then consistent with `cltv_expiry` in an HTLC being
the actual block height value for the CLTV and not a delta.
Secrets should not be exposed in-memory at the interface level as it
would be impossible the implement it against a hardware security
module/secure element.
