We have two sources which can call `handlePacketSettle`, either through
the link's `<-s.htlcPlex`, or the `<-s.resolutionMsgs`, which means the
`closeCircuit` could be call twice. Previously we already caught this
case inside `closeCircuit`, in that we would return a nil circuit upon
seeing `ErrUnknownCircuit`, indicating the circuit was removed. However,
we still need to account the case when the circuit is the process of
being closed, which is now fixed as we will ignore when seeing
`ErrCircuitClosing`.
For calculating the available auxiliary bandwidth of a channel, we need
access to the inbound custom wire records of the HTLC packet, which
might contain auxiliary information about the worth of the HTLC packet
apart from the BTC value being transported.
All the structs defined in the `channeldb/models` package are graph
related. So once we move all the graph CRUD code to the graph package,
it makes sense to have the schema structs there too. So this just moves
the `models` package over to `graph/db/models`.
This is a requirement for replacing the quit channel with a Context.
The Done() channel of a Context is always recv-only, so all users of
that channel must not expect a bidirectional channel.
This commit expands the definition of the dust limit to take into
account commitment fees as well as dust HTLCs. The dust limit is now
known as a fee exposure threshold. Dust HTLCs are fees anyways so it
makes sense to account for commitment fees as well. The link has
been modified slightly to calculate dust. In the future, the switch
dust calculations can be removed.
Here we notice that the only use of the Peer call on the link is
to find out what the peer's pubkey is. To avoid leaking handles to
IO actions outside the interface we reduce the surface area to
just return the peer's public key.
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 commit renames the method `GetPaymentResult` to be
`GetAttemptResult` to avoid potential confusion and to address the
one-to-many relationship between a payment and its attempts.
Previously, the Switch would not check waiting-close channels' fwdpkgs
for settles or fails to reforward. This could result in a force close
in a rare edge case if a restart occurred at the wrong time. Now,
waiting-close fwdpkgs are checked and the issue is avoided.
In this commit, we parse the new max fee field, and pass it through the
switch, all the way to the peer where it's ultimately passed into the
chan closer state machine.
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.
With this, extra calls to RemoveLink will wait for the link to
fully stop. This is accomplished by a map that stores a single stop
channel that callers to RemoveLink will listen on. This map is not
consulted when the Switch is shutting down and calls Stop on each
individual link. Though that could be added in the future, it is
not necessary.
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.
