Define an Electrum-friendly interface for ChannelMonitor where txids of
relevant transactions can be obtained. For any of these transactions
that are re-orged out of the chain, users must call
transaction_unconfirmed.
There is a possible race condition when both the latest block hash and
height are needed. Combine these in one struct and place them behind a
single lock.
Jeffrey Czyz [Wed, 31 Mar 2021 17:54:01 +0000 (13:54 -0400)]
Add txid to on-chain event tracking
When using Electrum, transactions are individually unconfirmed during a
reorg rather than by block. Store the txid of the transaction creating
the on-chain event so that it can be used to determine which events need
to be removed when a transaction is unconfirmed.
Jeffrey Czyz [Wed, 31 Mar 2021 17:23:57 +0000 (13:23 -0400)]
Flatten onchain_events_waiting_threshold_conf
Rather than mapping height to a vector of events, use a single vector
for all events. This allows for easily processing events by either
height or transaction. The latter will be used for an interface suitable
for Electrum.
Matt Corallo [Mon, 12 Apr 2021 17:48:29 +0000 (13:48 -0400)]
Return ChannelMonitors in a Vec, not HashMap when loading from disk
There's little reason for the HashMap - the ChannelMonitors are
already unique (enforced by file names), and the eventual HashMap
that users need when deserializing the `ChannelManager` is a
slightly different form (it requires no BlockHash entry).
Matt Corallo [Fri, 26 Mar 2021 22:07:24 +0000 (18:07 -0400)]
Take the full funding transaction from the user on generation
Instead of relying on the user to ensure the funding transaction is
correct (and panicing when it is confirmed), we should check it is
correct when it is generated. By taking the full funding transaciton
from the user on generation, we can also handle broadcasting for
them instead of doing so via an event.
Matt Corallo [Fri, 5 Mar 2021 02:42:42 +0000 (21:42 -0500)]
Don't clone Features during Dijkstras graph walk
We currently copy the features objects in each channel as we walk
the graph during route calculation. This implies a significant
amount of malloc traffic as the features flags object are stored
on the heap.
Instead, because they features being referenced are in the network
graph which we hold a reference to, we can simply store references
to them.
This nontrivially improves our get_route benchmark by around 5%.
Matt Corallo [Sat, 27 Mar 2021 16:49:42 +0000 (12:49 -0400)]
[router] Avoid re-processing peers when a score component decreases
While walking the graph doing Dijkstra's, we may decrease the
amount being sent along one path, and not others, based on the
htlc_minimum_msat value. This may result in a lower relative fees
on that path in comparison to others. In the extreme, this may
result in finding a second path to a node with a lower fee than the
first path found (normally impossible in a Dijkstra's
implementation, as we walk next hops in fee-order).
In such a case, we end up with parts of our state invalid as
further hops beyond that node have been filled in using the
original total fee information.
Instead, we simply track which nodes have been processed and ignore
and further updates to them (as it implies we've reduced the amount
we're sending to find a lower absolute fee, but a higher relative
fee, which isn't a better route).
We check that we are in exactly this case in test builds with new
in-line assertions. Note that these assertions successfully detect
the bug in the previous commit.
Sadly this requires an extra HashMap lookup every time we pop an
element off of our heap, though we can skip a number of heap pushes
during the channel walking.
Matt Corallo [Sat, 27 Mar 2021 01:50:54 +0000 (21:50 -0400)]
Add a random real-world-network-graph test for the router
This is the same code as was recently failing in our benchmarks,
adapted to use a random starting seed instead of a fixed one and
a smaller iteration to reduce runtime.
Matt Corallo [Sat, 27 Mar 2021 16:27:44 +0000 (12:27 -0400)]
[router] Calc min-to-node fees based on min value, not est value
When walking the network graph to calculate a route, we always
calculate the minimum fee which is required to make one further
hop. This avoids some extra hop processing at the end of each path
selection loop (saving around 10% runtime in our benchmarks).
However, if we use the real value which we expect
to send over a channel in that calculation, we may find an
alternate path to the same node which is more expensive but
capacity-constrained, resulting in us considering it cheaper as the
relative fee paid will be lower.
Instead, we can use the `minimal_value_contribution_msat`, which is
a constant through an entire path finding iteration, as the amount,
preventing any basis change in the relative fee paid.
Matt Corallo [Sat, 27 Mar 2021 02:56:37 +0000 (22:56 -0400)]
[router] Make Dijkstra's path scoring non-decreasing + consistent
Currently, the "best source" for a given node tracked during
Dijkstra's is updated with a different critera from the heap
sorting, resulting in loops in calculated paths.
This adds a test for the specific failure currently seen, utilizing
the new path-htlc-minimum tracking in the heap entries in place of
the per-hop htlc-minimum values which the MPP changeset partially
used.
Matt Corallo [Sat, 27 Mar 2021 02:31:57 +0000 (22:31 -0400)]
[router] Avoid re-selecting the same path over and over again
If we walk the network graph and find a route that meets are
payment amount and has a liquidiy limit far in excess of our
payment amount, we may select the same path several times in the
main path-gathering loop.
Instead, if the path we selected was not limited by the available
liquidity, we set the middle hop in the path's liquidity available
to zero, disabling that channel in future path finding steps.
Matt Corallo [Sat, 27 Mar 2021 02:53:35 +0000 (22:53 -0400)]
[router] Track full-path htlc-minimum-msat while graph-walking
Previously, we'd happily send funds through a path where, while
generating the path, in some middle hope we reduce the value being
sent to meet an htlc_maximum, making a later hop invalid due to it
no longer meeting its htlc_minimum. Instead, we need to track the
path's htlc-minimum while we're transiting the graph.
Matt Corallo [Sat, 27 Mar 2021 02:51:41 +0000 (22:51 -0400)]
[router] Do not fail if we are exactly (or 3x) limited by a maximum
The new MPP routing algorithm attempts to build paths with a higher
value than our payment to find paths which may allow us to pay a
fee to meet an htlc_minimum limit. This is great if we're
min-bounded, however it results in us rejecting paths where we are
bounded by a maximum near the end of the path, with fees, and then
bounded by a minimum earlier in the path. Further, it means we will
not find the cheapest path where paths have a lower relative fee
but a higher absolute fee.
Instead, we calculate routes using the actual amount we wish to
send. To maintain the previous behavior of searching for cheaper
paths where we can "pay the difference" to meet an htlc_minimum, we
detect if we were minimum-bounded during graph walking and, if we
are, we walk the graph again with a higher value.
Matt Corallo [Fri, 19 Mar 2021 00:32:20 +0000 (20:32 -0400)]
More regularly send an Error message when we force-close a channel
When we force-close a channel, for whatever reason, it is nice to
send an error message to our peer. This allows them to closes the
channel on their end instead of trying to send through it and
failing. Further, it may induce them to broadcast their commitment
transaction, possibly getting that confirmed and saving us on fees.
This commit adds a few more cases where we should have been sending
error messages but weren't. It also includes an almost-global
replace in tests of the second argument in
`check_closed_broadcast!()` from false to true (indicating an error
message is expected). There are only a few exceptions, notably
those where the closure is the result of our counterparty having
sent *us* an error message.
Matt Corallo [Tue, 16 Mar 2021 00:28:22 +0000 (20:28 -0400)]
Make `Channel`'s block connection API more electrum-friendly
Electrum clients primarily operate in a world where they query (and
subscribe to notifications for) transactions by script_pubkeys.
They may never learn very much about the actual blockchain and
orient their events around individual transactions, not the
blockchain.
This makes our ChannelManager interface somewhat more amenable to
such a client by splitting `block_connected` into
`transactions_confirmed` and `update_best_block`. The first handles
checking the funding transaction and storing its height/confirmation
block, whereas the second handles funding_locked and reorg logic.
Sadly, this interface is somewhat easy to misuse - notifying the
channel of the funding transaction being reorganized out of the
chain is complicated when the only notification received is that
a new block is connected at a given height. This will be addressed
in a future commit.
Matt Corallo [Tue, 16 Mar 2021 00:13:57 +0000 (20:13 -0400)]
Switch to height-based funding-tx tracking from conf-based tracking
Previously, we expected every block to be connected in-order,
allowing us to track confirmations by simply incrementing a counter
for each new block connected. In anticipation of moving to a
update-height model in the next commit, this moves to tracking
confirmations by simply storing the height at which the funding
transaction was confirmed.
This commit also corrects our "funding was reorganized out of the
best chain" heuristic, instead of a flat 6 blocks, it uses half the
confirmation count required as the point at which we force-close.
Even still, for low confirmation counts (eg 1 block), an ill-timed
reorg may still cause spurious force-closes, though that behavior
is not new in this commit.
Matt Corallo [Wed, 31 Mar 2021 23:54:32 +0000 (19:54 -0400)]
Cache our node ID in ChannelManager
While its not necessarily a common operation on a running node,
`get_our_node_id()` is used incredibly heavily in tests, and there
is no reason to not eat the extra ~64 bytes to just cache it.
Jeffrey Czyz [Sun, 21 Mar 2021 04:42:58 +0000 (00:42 -0400)]
Test register_output is called on dependent txn
chain::Filter::register_output may return an in-block dependent
transaction that spends the output. Test the scenario where the txdata
given to ChainMonitor::block_connected includes a commitment transaction
whose HTLC output is spent in the same block but not included in txdata.
Instead, it is returned by chain::Filter::register_output when given the
commitment transaction's HTLC output. This is a common scenario for
Electrum clients, which provided filtered txdata.
Jeffrey Czyz [Sun, 21 Mar 2021 03:54:21 +0000 (23:54 -0400)]
Mock-like expectations for TestChainSource
Add a method to TestChainSource to test chain::Filter expectations. This
is limited to register_output, allowing tests to assert that the method
was called with a specific output and dictate what the return value is.
Multiple expectations are checked in the order in which they were added.
Failure occurs if a call doesn't match the next expectation or if there
are unsatisfied expectations. If not expectations are added, then no
calls are checked.
Jeffrey Czyz [Wed, 10 Mar 2021 22:39:34 +0000 (14:39 -0800)]
Add rescan logic to ChainMonitor::block_connected
Electrum clients will only provide transaction data for outputs that
have been explicitly registered. Hence, upon registering new outputs,
recursively register any outputs to watch contained within dependent
transactions from the same block.
Jeffrey Czyz [Tue, 16 Mar 2021 00:32:28 +0000 (17:32 -0700)]
Include block hash for watched transaction output
When registering a watched transaction output, any in-block descendant
transactions spending the output must be supplied. Give the block hash
when registering such outputs such that this is possible. Otherwise,
spends from other blocks may be returned inadvertently.
Jeffrey Czyz [Wed, 10 Mar 2021 17:13:21 +0000 (09:13 -0800)]
Return optional Transaction from register_output
Electrum clients primarily operate by subscribing to notifications of
transactions by script pubkeys. Therefore, they will send filtered
transaction data without including dependent transactions. Outputs for
such transactions must be explicitly registered with these clients.
Therefore, upon block_connected, provide a mechanism for an Electrum-
backed chain::Filter to return new transaction data to scan.
Matt Corallo [Mon, 15 Mar 2021 23:49:51 +0000 (19:49 -0400)]
Enforce block connection ordering in unit and functional tests
This expands the assertions on block ordering to apply to
`#[cfg(test)]` builds in addition to normal builds, requiring that
unit and functional tests have syntactically-valid (ie the previous
block hash pointer and the heights match the blocks) blockchains.
This requires a reasonably nontrivial diff in the functional tests
however it is mostly straightforward changes.
Matt Corallo [Wed, 17 Mar 2021 17:11:48 +0000 (13:11 -0400)]
Fix block connection ordering in a number of functional tests
Many functional tests rely on being able to call block_connected
arbitrarily, jumping back in time to confirm a transaction at a
specific height. Instead, this takes us one step towards having a
well-formed blockchain in the functional tests.
We also take this opportunity to reduce the number of blocks
connected during tests, requiring a number of constant tweaks in
various functional tests.
Co-authored-by: Valentine Wallace <vwallace@protonmail.com> Co-authored-by: Matt Corallo <git@bluematt.me>
Matt Corallo [Fri, 5 Mar 2021 16:02:42 +0000 (11:02 -0500)]
Add assertions for in-order block [dis]connection in ChannelManager
Sadly the connected-in-order tests have to be skipped in our normal
test suite as many tests violate it. Luckily we can still enforce
it in the tests which run in other crates.
Co-authored-by: Matt Corallo <git@bluematt.me> Co-authored-by: Jeffrey Czyz <jkczyz@gmail.com>
Matt Corallo [Thu, 18 Mar 2021 03:12:47 +0000 (23:12 -0400)]
Ignore patch codecov as long as total coverage is within 1% of base
In some PRs, codecov gets mad that the coverage of the patch itself
is lower than the base. In most cases, we largely don't want a Big
Red X, at least as long as the total coverage has not gone down
substantially.