The spec allows the final HTLC value and CLTV expiry to exceed
the value and expiry specified in the payload of the last hop
of the onion packet. We were over-restricting it to require
that it matches exactly.
In this commit, we add a new LinkFailureDisconnect action that'll be
used if we detect that the remote party hasn't sent a revoke and ack
when it actually should.
Before this commit, we would log our action, tear down the link, but
then not actually force a connection recycle, as we assumed that if the
TCP connection was actually stale, then the read/write timeout would
expire.
In practice this doesn't always seem to be the case, so we make a strong
action here to actually force a disconnection in hopes that either side
will reconnect and keep the good times rollin' 🕺.
In this commit, we add a new LinkFailureAction enum to take over the old
force close bool. Force closing isn't the only thing we might want to do
when we decide to fail the link, so this is a prep refactoring for an
upcoming change.
Since the TowerClient now has a callback that it can use to retrieve the
retribution for a certain channel and commit height, let it use this
call back instead of requiring the info to be passed to it through
BackupState.
This commit replaces `FundingLocked` found in docs using the following
command,
```shell
find . -name "*.go" -exec sed -i '' 's/FundingLocked/ChannelReady/g' {} \;
find . -name "*.go" -exec sed -i '' 's/FundingLock/ChannelReady/g' {} \;
```
Add a new subpackage to `lnd/channeldb` to hold some of the types that
are used in the package itself and in other packages that should not
depend on `channeldb`.
This intent of this change is to prevent privacy leaks when routing
with aliases and also to allow routing when using an alias. The
aliases are our aliases.
Introduces are two maps:
* aliasToReal:
This is an N->1 mapping for a channel. The keys are the set of
aliases and the value is the confirmed, on-chain SCID.
* baseIndex:
This is also an N->1 mapping for a channel. The keys are the set
of aliases and the value is the "base" SCID (whatever is in the
OpenChannel.ShortChannelID field). There is also a base->base
mapping, so not all keys are aliases.
The above maps are populated when a link is added to the switch and
when the channel has confirmed on-chain. The maps are not removed
from if the link is removed, but this is fine since forwarding won't
occur.
* getLinkByMapping
This function is introduced to adhere to the spec requirements that
using the confirmed SCID of a private, scid-alias-feature-bit
channel does not work. Lnd implements a stricter version of the spec
and disallows this behavior if the feature-bit was negotiated, rather
than just the channel type. The old, privacy-leak behavior is
preserved.
The spec also requires that if we must fail back an HTLC, the
ChannelUpdate must use the SCID of whatever was in the onion, to avoid
a privacy leak. This is also done by passing in the relevant SCID to
the mailbox and link. Lnd will also cancel back on the "incoming" side
if the InterceptableSwitch was used or if the link failed to decrypt
the onion. In this case, we are cautious and replace the SCID if an
alias exists.
This introduces a BigSize migration that is used to expand the width
of the ChannelStatus and ChannelType fields. Three channel "types"
are added - ZeroConfBit, ScidAliasChanBit, and ScidAliasFeatureBit.
ScidAliasChanBit denotes that the scid-alias channel type was
negotiated for the channel. ScidAliasFeatureBit denotes that the
scid-alias feature bit was negotiated during the *lifetime* of the
channel. Several helper functions on the OpenChannel struct are
exposed to aid callers from different packages.
The RefreshShortChanID has been renamed to Refresh.
A new function BroadcastHeight is used to guard access to the
mutable FundingBroadcastHeight member. This prevents data races.
Warning messages are intended to add "softer" failure modes for peers,
so to start with we simply log the warnings sent to us. While we "may"
disconnect from the peer according to the spec, we start with the least
extreme option (which is also not a change in behavior because
previously we'd just log that we received an unknown odd message).
This allows Switch-initiated payments to be failed back if they don't
make it into a commitment. Prior to this commit, a Switch-initiated
HTLC could get "lost" meaning the circuit wouldn't get deleted except
if conditions were "right" and the network result store would never
be made aware of the HTLC's fate. Switch-initiated HTLC's are now
passed to the link's mailbox to ensure they can be failed back.
This change also special-cases the ErrDuplicateKeystone error from
OpenCircuits(...) so that callers of updateCommitTx() in the link
don't send an Error to the peer if they encounter the keystone error.
With the first async change, the keystone error should now always
be recoverable.
This commit changes the `NewBreachRetribution` to use the new revocation
log format, while maintaining the compatibilty to use an older
revocation log format. Unit tests have been added to make sure a breach
retribution can be created in both log formats.
This also means the watch tower needs to pass the relevant commit tx at
its backup height when creating the breach retribution during backing
up. This is achieved by recording the current remote commitment state
before advancing the remote commitment chain.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
The counter-party shouldn't be doing this anyways as they would be
giving away a preimage for free. Them doing this would bork their
own channel due to open circuits not getting trimmed on startup.
Removing this faulty behavior also makes it easier to reason about
the circuit logic.
Pass htlc amount down to the channel so that we don't need to rely
on minHtlc (and pad it when the channel sets a 0 min htlc). Update
test to just check some sane values since we're no longer relying
on minHtlc amount at all.
This commit extends the Mailbox interface with the SetDustClosure,
SetFeeRate, and DustPackets methods. This enables the mailbox to
report the dust exposure to the Switch when the Switch decides whether
to forward a dust packet. The dust is counted from the time an Add is
introduced via AddPacket until it is removed via AckPacket. This can
lead to some packets being counted twice before they are signed for,
but this is a trade-off between accuracy and simplicity.
This allows a caller to ensure to optimistically shut down the link
if the channel is clean. If the channel is not clean, an error is
returned and the link continues functioning as normal. The caller
should also call RemoveLink to ensure that the link isn't seen as
usable within the switch.
In lnd, log messages about channels are generally logged with a
reference to their channel point rather than the short channel id.
Channel point is reorg-resistant and also easier to look up in for
example a block explorer.
In the link however, all log messages are accompanied by short channel
id. This makes it difficult to grep a log for all channel activity. The
PEER message for example which are often crucial to analyse, are logged
with channel points.
This commit modifies the link logging to also use channel points.
Until now, clients of SubscribeHTLCEvents didn't have access to the settled preimage. The API allows to intercept forward event and to be updated on forward events however the forward+settle event does not include the payment preimage. This pr changes allows it.
