As the variable name implies holder_selected_chan_reserve_msat is
intended to be in millisatoshis, but is instead calculated in
satoshis.
We fix that error here and update the relevant tests to more
accurately calculate the expected reserve value and test both
success and failure cases.
Bug discovered by chanmon_consistency fuzz target.
Private nodes should never wish to forward HTLCs at all, which we
support here by disabling forwards out over private channels by
default. As private nodes should not have any public channels, this
suffices, without allowing users to disable forwarding over
channels announced in the routing graph already.
Closes#969
Currently the base fee we apply is always the expected cost to
claim an HTLC on-chain in case of closure. This results in
significantly higher than market rate fees [1], and doesn't really
match the actual forwarding trust model anyway - as long as
channel counterparties are honest, our HTLCs shouldn't end up
on-chain no matter what the HTLC sender/recipient do.
While some users may wish to use a feerate that implies they will
not lose funds even if they go to chain (assuming no flood-and-loot
style attacks), they should do so by calculating fees themselves;
since they're already charging well above market-rate,
over-estimating some won't have a large impact.
Worse, we current re-calculate fees at forward-time, not based on
the fee we set in the channel_update. This means that the fees
others expect to pay us (and which they calculate their route based
on), is not what we actually want to charge, and that any attempt
to forward through us is inherently race-y.
This commit adds a configuration knob to set the base fee
explicitly, defaulting to 1 sat, which appears to be market-rate
today.
[1] Note that due to an msat-vs-sat bug we currently actually
charge 1000x *less* than the calculated cost.
If we are a public node and have a private channel, our
counterparty needs to know the fees which we will charge to forward
payments to them. Without sending them a channel_update, they have
no way to learn that information, resulting in the channel being
effectively useless for outbound-from-us payments.
This commit fixes our lack of channel_update messages to private
channel counterparties, ensuring we always send them a
channel_update after the channel funding is confirmed.
This adds four new fields in `ChannelDetails`:
1. holder_selected_ and counterparty_selected_channel_reserve_delay
are useful to determine what amount of the channel is
unavailable for payments.
2. confirmations_required is useful when awaiting funding
confirmation to determine how long you will need to wait.
3. to_self_delay is useful to determine how long it will take to
receive funds after a force-close.
Fixes#983.
We had a user who pointed out that we weren't creating
`SpendableOutputs` events when we should have been after they
called `ChannelMonitor::best_block_updated` with a block well
after a CSV locktime and then called
`ChannelMonitor::transactions_confirmed` with the transaction which
we should have been spending (with a block height/hash a ways in
the past).
This was due to `ChannelMonitor::transactions_confirmed` only
calling `ChannelMonitor::block_confirmed` with the height at which
the transactions were confirmed, resulting in all checks being done
against that, not the current height.
Further, in the same scenario, we also would not fail-back and HTLC
where the HTLC-Timeout transaction was confirmed more than
ANTI_REORG_DELAY blocks ago.
To address this, we use the best block height for confirmation
threshold checks in `ChannelMonitor::block_confirmed` and pass both
the confirmation and current heights through to
`OnchainTx::update_claims_view`, using each as appropriate.
Fixes#962.
No matter the context, if we're told about a block which is
guaranteed by our API semantics to be on the best chain, and it has
a higher height than our current understanding of the best chain,
we should update our understanding. This avoids complexity
in `block_confirmed` by never having a height set which is *higher*
than our current best chain, potentially avoiding some bugs in the
rather-complicated code.
It also requires a minor test tweak as we in some cases now no
longer broadcast a conflicting transaction after the original has
reached the ANTI_REORG_DELAY.
This updates a number of log sites in channel and channelmanager to
* Be a bit more verbose at the TRACE level,
* Move some error/useful messages to the ERROR/WARN/INFO level,
* Add new logs to always log once at the DEBUG level when we
send/receive a commitment_signed (with some extra data),
* Include the channel id being operated on in more log messages.
lnd has a long-standing bug where, upon reconnection, if the
channel is not yet confirmed they will not send a
channel_reestablish until the channel locks in. Then, they will
send a funding_locked *before* sending the channel_reestablish
(which is clearly a violation of the BOLT specs). We copy
c-lightning's workaround here and simply store the funding_locked
message until we receive a channel_reestablish.
See-also https://github.com/lightningnetwork/lnd/issues/4006Fixes#963
This stores transaction templates temporarily until their locktime
is reached, avoiding broadcasting (or RBF bumping) transactions
prior to their locktime. For those broadcasting transactions
(potentially indirectly) via Bitcoin Core RPC, this ensures no
automated rebroadcast of transactions on the client side is
required to get transactions confirmed.
Currently, we only send an update_channel message after
disconnecting a peer and waiting some time. We do not send a
followup when the peer has been reconnected for some time.
This changes that behavior to make the disconnect and reconnect
channel updates symmetric, and also simplifies the state machine
somewhat to make it more clear.
Finally, it serializes the current announcement state so that we
usually know when we need to send a new update_channel.
This increases the CLTV_CLAIM_BUFFER constant to 18, much better
capturing how long it takes to go on chain to claim payments.
This is also more in line with other clients, and the spec, which
sets the default CLTV delay in invoices to 18.
As a side effect, we have to increase MIN_CLTV_EXPIRY_DELTA as
otherwise as are subject to an attack where someone can hold an
HTLC being forwarded long enough that we *also* close the channel
on which we received the HTLC.
Current Bitcoin Core's policy will reject a p2wsh as a dust if it's
under 330 satoshis. A typical p2wsh output is 43 bytes big to which
Core's `GetDustThreshold()` sums up a minimal spend of 67 bytes (even
if a p2wsh witnessScript might be smaller). `dustRelayFee` is set
to 3000 sat/kb, thus 110 * 3000 / 1000 = 330. As all time-sensitive
outputs are p2wsh, a value of 330 sat is the lower bound desired
to ensure good propagation of transactions. We give a bit margin to
our counterparty and pick up 660 satoshis as an accepted
`dust_limit_satoshis` upper bound.
As this reasoning is tricky and error-prone we hardcode it instead of
letting the user picking up a non-sense value.
Further, this lower bound of 330 sats is also hardcoded as another constant
(MIN_DUST_LIMIT_SATOSHIS) instead of being dynamically computed on
feerate (derive_holder_dust_limit_satoshis`). Reducing risks of
non-propagating transactions in casee of failing fee festimation.
For users who get PaymentPreimages via
`get_payment_secret_preimage`, they need to provide the
PaymentPreimage back in `claim_funds` but they aren't actually
given the preimage anywhere.
This commit gives users the PaymentPreimage in the
`PaymentReceived` event.
Like the payment_secret parameter, this paramter has been the source
of much confusion, so we just drop it.
Users should prefer to do this check when registering the payment
secret instead of at claim-time.
This allows users to store metadata about an invoice at
invoice-generation time and then index into that storage with a
general-purpose id when they call `get_payment_secret`. They will
then be provided the same index when the payment has been received.
Our current PaymentReceived API is incredibly easy to mis-use -
the "obvious" way to implement a client is to always call
`ChannelManager::claim_funds` in response to a `PaymentReceived`
event. However, users are *required* to check the payment secret
and value against the expected values before claiming in order to
avoid a number of potentially funds-losing attacks.
Instead, if we rely on payment secrets being pre-registered with
the ChannelManager before we receive HTLCs for a payment we can
simply check the payment secrets and never generate
`PaymentReceived` events if they do not match. Further, when the
user knows the value to expect in advance, we can have them
register it as well, allowing us to check it for them.
Other implementations already require payment secrets for inbound
payments, so this shouldn't materially lose compatibility.
This prepares us for requiring payment_secrets for all received
payments, by demonstrating test changes work even prior to the new
requirement.
In order to avoid needing to pipe payment secrets through to
additional places in the claim logic and then removing that
infrastructure once payment secrets are required, we use the new
payment secret storage in ChannelManager to look up the payment
secret for any given pament hash in claim and fail-back functions.
This part of the diff is reverted in the next commit.
In order to reduce code movement in the next commit, this commit
simply tweaks get_payment_preimage_hash!() and related functions in
functional tests to return a payment secret. Further, we ensure
that we always call get_payment_preimage_hash!() with the node
which will ultimately receive the payment.
