In this commit, we extend the existing HtlcSatifiesPolicy method to also
accept timelock and height information. This is required as an upcoming
commit will fix an existing bug in the forwarding logic wherein we use
the time lock policies of the incoming node rather than that of the
outgoing node.
In this commit, we fix a bug in the generateHops helper function. Before
this commit, it erroneously used the CLTV delta of the current hop,
rather than that of the prior hop when computing the payload. This was
incorrect, as when computing the timelock for the incoming hop, we need
to factor in the CTLV delta of the outgoing lock, not the incoming lock.
In this commit, we add a new test to the switch:
TestForwardingAsymmetricTimeLockPolicies. This test ensures that a link
has two channels, one of which has a greater CLTV delta than the latter,
that a payment will successfully be routed across the channels. Atm, the
test fails (including the fix to hop payload generation included in the
next commit).
Atm, due to the way that we check forwarding policies, we'll reject this
payment as we're attempting to enforce the policy of the incoming link
(cltv delta of 7), instead of that of the outgoing link (cltv delta of
6). As a result, atm, the incoming link checks if (incoming_timeout -
delta < outgoing_timeout). For the values in the test case: 112 - 7 <
106 -> 105 < 106, this check fails. The payload is proper, but the check
itself should be applied at the outgoing hop.
In this commit, we add a timeout within the writeMessage method when we go to write to the socket. We do this as otherwise, if the other peer is blocked for some reason, we'll never actually unblock ourselves, which may cause issues in other sub-systems waiting on this write call. For now, we use a value of 10 seconds, and will adjust in the future if we deem this time period too short.
In this commit, we add a new package level mutex. Each time we decode a
new set of chan IDs w/ zlib, we also grab this mutex. The purpose here
is to ensure that we only EVER allocate the maxZlibBufSize globally
across all peers. Otherwise, it may be possible for us to allocate up to
64 MB for _each_ peer, exposing an easy OOM attack vector.
In this commit, we implement zlib encoding and decoding for the channel
range queries. Notably, we utilize an io.LimitedReader to ensure that we
can enforce a hard cap on the total number of bytes we'll ever allocate
in a decoding attempt.
In this commit, we modify the removeLink method to be more asynchronous.
Before this commit, we would attempt to block until the peer exits.
However, it may be the case that at times time, then target link is
attempting to forward a batch of packets to the switch (forwardBatch).
Atm, this method doesn't pass in an external context/quit, so we can't
cancel this message/request. As a result, we'll now ensure that
`removeLink` doesn't block, so we can resume the switch's main loop as
soon as possible.
This commit handles a racy condition within the breacharbiter's justice
tx procedure. For backends that have no mempool we would check if an
HTLC output was spent and then try broadcasting the justice tx, but this
would fail since we wouldn't detect the spend before it was in a block.
The result was that we would continuously attempt to broadcast the
transaction, effectively ending up in an endless (until the second-level
tx actually comfirmed) loop.
Instead we now register for spend notifications in case broadcasting the
transaction fails, and then wait for any of the notifications to be
sent before trying again.
This is a necessary step to be able to make lnd work well only with
confimed transactions, and was a better solution than introducing
timeouts within the broadcast loop (which complicates integration
tests).
In this commit, we move the block height dependency from the links in
the switch to the switch itself. This is possible due to a recent change
on the links no longer depending on the block height to update their
commitment fees.
We'll now only have the switch be alerted of new blocks coming in and
links will retrieve the height from it atomically.
