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 replaces the clock used in the unit test
`TestMailBoxAddExpiry`. Previously the `TestClock` is used, resulting in
the unit test being not so "unit" as the maintainer needs to know the
detailed implementation of `clock.Clock`, resulting in debugging a
failed unit test more difficult as the cognitive cost is high.
Re-implement `clock.Clock` also means we need to maintain more. This is
now solved by using mock clock so we can ignore the implementation
details and care only the returned results.
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 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
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.
As part of the preparation to the switch interceptor feature, this
function is changed to return error instead of error channel that
is closed automatically.
Returning an error channel has become complex to maintain and
implement when adding more asynchronous flows to the switch.
The change doesn't affect the current behavior which logs the
errors as before.
Modifies some of the older mailbox tests that were left untouched as of
PR #4174 to use the new mailbox test context. This ensures that the
config members of each mailbox's config are properly initialized. In
certain instances where travis is slow, this would cause test panics.
Now that packet failure is handled by the mailbox, we can now enforce
a delivery deadline and fail the packet if it the deadilne is exceeded.
This gives senders quicker feedback about tried routes, and allows them
to try alternative paths to the destination in the meantime.
This commit splits the packet courier internally into two distinct
queues, one for adds and one for settles+fails. This allows us to
prioritize HTLCs that will clear the commitment transaction and make
space for adds. Previously this responsibility was handled by the
overflow queue.
This commit moves the current logic for sending failures out of the link
and into the mailbox in preparation for our failing delayed htlcs. We do
so because the mailbox may need to fail packets while the link is
offline, and needs to be able to complete the task without member
methods on the link.
The src/dest terminology for routing packets is kind of confusing
because the source HTLC may not be the source of the packet for
settles/fails traversing the circuit in the opposite direction. This
changes the nomenclature to incoming/outgoing and always references
the HTLCs themselves.
In this commit, we add a new abstraction to the package: the mailBox.
The mailBox is a non-blocking, concurrent safe, in-order queue for
delivering messages to a given channelLink instance. With this
abstraction in place, we can now allow the switch to no longer launch a
new goroutine for each forwarded HTLC, or instantiated user payment.
