feature-bit channels
This allows opening zero-conf chan-type, scid-alias chan-type, and
scid-alias feature-bit channels. scid-alias chan-type channels are
required to be private. Two paths are available for opening a zero-conf
channel:
* explicit chan-type negotiation
* LDK carve-out where chan-types are not used, LND is on the
receiving end, and a ChannelAcceptor is used to enable zero-conf
When a zero-conf channel is negotiated, the funding manager:
* sends a FundingLocked with an alias
* waits for a FundingLocked from the remote peer
* calls addToRouterGraph to persist the channel using our alias in
the graph. The peer's alias is used to send them a ChannelUpdate.
* wait for six confirmations. If public, the alias edge in the
graph is deleted and replaced (not atomically) with the confirmed
edge. Our policy is also read-and-replaced, but the counterparty's
policy won't exist until they send it to us.
When a scid-alias-feature channel is negotiated, the funding manager:
* sends a FundingLocked with an alias:
* calls addToRouterGraph, sends ChannelUpdate with the confirmed SCID
since it exists.
* when six confirmations occurs, the edge is deleted and re-inserted
since the peer may have sent us an alias ChannelUpdate that we are
storing in the graph.
Since it is possible for a user to toggle the scid-alias-feature-bit
to on while channels exist in the funding manager, care has been taken
to ensure that an alias is ALWAYS sent in the funding_locked message
if this happens.
An OptionalMsgField has been added that allows outside subsystems
to provide a short channel id we should insert into a ChannelUpdate
that we then sign and send to our peer.
When the gossiper receives a ChannelUpdate, it will query the
alias manager by the passed-in FindBaseByAlias function to determine
if the short channel id in the ChannelUpdate points to a known
channel. If this lookup returns an error, we'll fallback to using
the original id in the ChannelUpdate when querying the router.
The lookup and potential fallback must occur in order to properly
lock the multimutex, query the correct router channels, and rate
limit the correct short channel id. An unfortunate side effect of
receiving ChannelUpdates from our peer that reference on of our
aliases rather than the real SCID is that we must store this policy.
Yet it is not broadcast-able. Care has been taken to ensure the
gossiper does not broadcast *any* ChannelUpdate with an alias SCID.
The cachedNetworkMsg uses the new processedNetworkMsg struct. This
is necessary so that delete-and-reinsert in the funding manager
doesn't process a ChannelUpdate twice and end up in a deadlock since
the err chan is no longer being used.
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.
When testing serializing revocation log, we need to also copy its
`HTLCEntries` as the serialization of the HTLC involves a writing to the
`htlc.amtTlv` field.
Previously, in `migration25.OpenChannel`, there was a private field
`chanStatus` used to keep track of the channel status. The following
migrations, `migration26` and `migration27` also have their own
`OpenChannel` defined, with `migration26` inherited from `migration25`,
and `migration27` inherited from `migration26`. The private field
`chanStatus`, however, is NOT inherited and each of the migrations uses
its own. This is fine for reading and writing as, under the hood, the
`chanStatus` is just a `uint8` value. Because each migration has its own
fetcher and putter, it can safely access its private field to read and
write it correctly.
The issue pops up when we use the method
`migration25.FundingTxPresent()`. Because it's evaluating its channel
status using its own private field `chanStatus`, this field would always
be the default value(`ChanStatusDefault`), leading the statement
`!c.hasChanStatus(ChanStatusRestored)` to always be true. Thus a
restored channel will be mistakenly considered to have funding tx
present, causing failures in reading the channel info in the following
migrations.
We fix this by exporting the `ChanStatus` field so its value can be set
by following migrations.
This commit adds a new migration to patch the two balance fields,
`InitialLocalBalance` and `InitialRemoteBalance` for the historical
channels. Because they are not saved previously, for historical channels
prior to the revocation log PR, these fields will be empty.
This can cause an intermittent panic otherwise if bbolt remaps itself
via munmap and mmap. From bbolt's documentation:
* Byte slices returned from Bolt are only valid during a transaction.
Once the transaction has been committed or rolled back then the memory
they point to can be reused by a new page or can be unmapped from
virtual memory and you'll see an unexpected fault address panic when
accessing it.
This commit uses bigsize record to encode the htlc amount, which could
save us 3 more bytes if the encoded value is no greater than roughly
0.043 bitcoin. The uint test has been updated with a more realistic
values to reflect the actual gain.
This commit adds `revocationLogBucket` using the new sub-bucket key
"revocation-log" to store the minimal info needed. Two structs,
`RevocationLog` and `HTLCEntry` are created to represent the disk
records.
This commit deletes the function `BalancesAtHeight` since its only
usague is to find the push amount, which can be achieved by saving the
initial balances.
Another reason to remove it is to pave the way to incooperate our new
revocation log. If we ever need this function again, we can add it back
by visiting all the revocation logs to calculate the balances at a given
height.
This commit replaces the method RevocationLogTail which in used in our
unit test with a private method revocationLogTailCommitHeight. The new
method returns the commit height only since that's what's needed in the
test.
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
For older nodes, this bucket was never created, so we'll get an error if
we try and query it. In this commit, we catch this error like we do when
a given channel doesn't have the information (but the bucket actually
exists).
Fixes#6155
In this commit, we modify the implementation of ForEachChannel to
utilize the new kvdb method ForAll. This greatly reduces the number of
round-trips to the database needed to iterate over all channels
in the graph.
