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Merge pull request #5428 from wpaulino/enforce-anchor-reserve

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lnwallet: prevent anchor reserve enforcement on legacy inbound channel
This commit is contained in:
Olaoluwa Osuntokun 2021-06-28 16:08:43 -07:00 committed by GitHub
commit 44e461b233
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 88 additions and 69 deletions
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48
lntest/itest/lnd_onchain_test.go
View File

@ -179,7 +179,8 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
net.ConnectNodes(ctxt, t.t, alice, bob)
// Send just enough coins for Alice to open a channel without a change output.
// Send just enough coins for Alice to open a channel without a change
// output.
const (
chanAmt = 1000000
feeEst = 8000
@ -205,20 +206,45 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
// Alice opens a smaller channel. This works since it will have a
// change output.
ctxt, _ = context.WithTimeout(context.Background(), defaultTimeout)
aliceChanPoint := openChannelAndAssert(
aliceChanPoint1 := openChannelAndAssert(
ctxt, t, net, alice, bob,
lntest.OpenChannelParams{
Amt: chanAmt / 2,
Amt: chanAmt / 4,
},
)
// If Alice tries to open another anchor channel to Bob, Bob should not
// reject it as he is not contributing any funds.
aliceChanPoint2 := openChannelAndAssert(
ctxt, t, net, alice, bob, lntest.OpenChannelParams{
Amt: chanAmt / 4,
},
)
// Similarly, if Alice tries to open a legacy channel to Bob, Bob should
// not reject it as he is not contributing any funds. We'll restart Bob
// to remove his support for anchors.
err = net.RestartNode(bob, nil)
require.NoError(t.t, err)
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = alice.WaitForNetworkChannelOpen(ctxt, aliceChanPoint)
aliceChanPoint3 := openChannelAndAssert(
ctxt, t, net, alice, bob, lntest.OpenChannelParams{
Amt: chanAmt / 4,
},
)
chanPoints := []*lnrpc.ChannelPoint{
aliceChanPoint1, aliceChanPoint2, aliceChanPoint3,
}
for _, chanPoint := range chanPoints {
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = alice.WaitForNetworkChannelOpen(ctxt, chanPoint)
require.NoError(t.t, err)
ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
err = bob.WaitForNetworkChannelOpen(ctxt, aliceChanPoint)
err = bob.WaitForNetworkChannelOpen(ctxt, chanPoint)
require.NoError(t.t, err)
}
// Alice tries to send all coins to an internal address. This is
// allowed, since the final wallet balance will still be above the
@ -316,7 +342,9 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
// Alice closes channel, should now be allowed to send everything to an
// external address.
closeChannelAndAssert(ctxt, t, net, alice, aliceChanPoint, false)
for _, chanPoint := range chanPoints {
closeChannelAndAssert(ctxt, t, net, alice, chanPoint, false)
}
newBalance := waitForConfirmedBalance()
if newBalance <= aliceBalance {
@ -338,11 +366,11 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
// generated above.
block = mineBlocks(t, net, 1, 1)[0]
// The sweep transaction should have two inputs, the change output from
// the previous sweep, and the output from the coop closed channel.
// The sweep transaction should have four inputs, the change output from
// the previous sweep, and the outputs from the coop closed channels.
sweepTx = block.Transactions[1]
if len(sweepTx.TxIn) != 2 {
t.Fatalf("expected 2 inputs instead have %v", len(sweepTx.TxIn))
if len(sweepTx.TxIn) != 4 {
t.Fatalf("expected 4 inputs instead have %v", len(sweepTx.TxIn))
}
// It should have a single output.

101
lnwallet/wallet.go
View File

@ -595,33 +595,11 @@ func (l *LightningWallet) PsbtFundingVerify(pendingChanID [32]byte,
"reservation ID %v", pid)
}
// Now the the PSBT has been verified, we can again check whether the
// value reserved for anchor fee bumping is respected.
numAnchors, err := l.currentNumAnchorChans()
if err != nil {
return err
}
// If this commit type is an anchor channel we add that to our counter,
// but only if we are contributing funds to the channel. This is done
// to still allow incoming channels even though we have no UTXOs
// available, as in bootstrapping phases. We only count public
// channels.
// Now the the PSBT has been populated and verified, we can again check
// whether the value reserved for anchor fee bumping is respected.
isPublic := pendingReservation.partialState.ChannelFlags&lnwire.FFAnnounceChannel != 0
if pendingReservation.partialState.ChanType.HasAnchors() &&
intent.LocalFundingAmt() > 0 && isPublic {
numAnchors++
}
// We check the reserve value again, this should already have been
// checked for regular FullIntents, but now the PSBT intent is also
// populated.
return l.WithCoinSelectLock(func() error {
_, err := l.CheckReservedValue(
intent.Inputs(), intent.Outputs(), numAnchors,
)
return err
})
hasAnchors := pendingReservation.partialState.ChanType.HasAnchors()
return l.enforceNewReservedValue(intent, isPublic, hasAnchors)
}
// PsbtFundingFinalize looks up a previously registered funding intent by its
@ -809,38 +787,15 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
// Now that we have a funding intent, we'll check whether funding a
// channel using it would violate our reserved value for anchor channel
// fee bumping. We first get our current number of anchor channels.
numAnchors, err := l.currentNumAnchorChans()
if err != nil {
fundingIntent.Cancel()
req.err <- err
req.resp <- nil
return
}
// If this commit type is an anchor channel we add that to our counter,
// but only if we are contributing funds to the channel. This is done
// to still allow incoming channels even though we have no UTXOs
// available, as in bootstrapping phases. We only count public
// channels.
isPublic := req.Flags&lnwire.FFAnnounceChannel != 0
if req.CommitType == CommitmentTypeAnchorsZeroFeeHtlcTx &&
fundingIntent.LocalFundingAmt() > 0 && isPublic {
numAnchors++
}
// fee bumping.
//
// Check the reserved value using the inputs and outputs given by the
// intent. Not that for the PSBT intent type we don't yet have the
// intent. Note that for the PSBT intent type we don't yet have the
// funding tx ready, so this will always pass. We'll do another check
// when the PSBT has been verified.
err = l.WithCoinSelectLock(func() error {
_, err := l.CheckReservedValue(
fundingIntent.Inputs(), fundingIntent.Outputs(),
numAnchors,
)
return err
})
isPublic := req.Flags&lnwire.FFAnnounceChannel != 0
hasAnchors := req.CommitType == CommitmentTypeAnchorsZeroFeeHtlcTx
err = l.enforceNewReservedValue(fundingIntent, isPublic, hasAnchors)
if err != nil {
fundingIntent.Cancel()
@ -893,6 +848,42 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
req.err <- nil
}
// enforceReservedValue enforces that the wallet, upon a new channel being
// opened, meets the minimum amount of funds required for each advertised anchor
// channel.
//
// We only enforce the reserve if we are contributing funds to the channel. This
// is done to still allow incoming channels even though we have no UTXOs
// available, as in bootstrapping phases.
func (l *LightningWallet) enforceNewReservedValue(fundingIntent chanfunding.Intent,
isPublic, hasAnchors bool) error {
// Only enforce the reserve when an advertised channel is being opened
// in which we are contributing funds to. This ensures we never dip
// below the reserve.
if !isPublic || fundingIntent.LocalFundingAmt() == 0 {
return nil
}
numAnchors, err := l.currentNumAnchorChans()
if err != nil {
return err
}
// Add the to-be-opened channel.
if hasAnchors {
numAnchors++
}
return l.WithCoinSelectLock(func() error {
_, err := l.CheckReservedValue(
fundingIntent.Inputs(), fundingIntent.Outputs(),
numAnchors,
)
return err
})
}
// currentNumAnchorChans returns the current number of non-private anchor
// channels the wallet should be ready to fee bump if needed.
func (l *LightningWallet) currentNumAnchorChans() (int, error) {