func testCoinSelector(tests []coinSelectTest, t *testing.T) {
for testIndex, test := range tests {
cs, err := test.selector.CoinSelect(test.targetValue, test.inputCoins)
if err != test.expectedError {
t.Errorf("[%d] expected a different error: got=%v, expected=%v", testIndex, err, test.expectedError)
continue
}
if test.expectedCoins != nil {
if cs == nil {
t.Errorf("[%d] expected non-nil coinset", testIndex)
continue
}
coins := cs.Coins()
if len(coins) != len(test.expectedCoins) {
t.Errorf("[%d] expected different number of coins: got=%d, expected=%d", testIndex, len(coins), len(test.expectedCoins))
continue
}
for n := 0; n < len(test.expectedCoins); n++ {
if coins[n] != test.expectedCoins[n] {
t.Errorf("[%d] expected different coins at coin index %d: got=%#v, expected=%#v", testIndex, n, coins[n], test.expectedCoins[n])
continue
}
}
coinSet := coinset.NewCoinSet(coins)
if coinSet.TotalValue() < test.targetValue {
t.Errorf("[%d] targetValue not satistifed", testIndex)
continue
}
}
}
}
func TestCoinSet(t *testing.T) {
cs := coinset.NewCoinSet(nil)
if cs.PopCoin() != nil {
t.Error("Expected popCoin of empty to be nil")
}
if cs.ShiftCoin() != nil {
t.Error("Expected shiftCoin of empty to be nil")
}
cs.PushCoin(coins[0])
cs.PushCoin(coins[1])
cs.PushCoin(coins[2])
if cs.PopCoin() != coins[2] {
t.Error("Expected third coin")
}
if cs.ShiftCoin() != coins[0] {
t.Error("Expected first coin")
}
mtx := coinset.NewMsgTxWithInputCoins(cs)
if len(mtx.TxIn) != 1 {
t.Errorf("Expected only 1 TxIn, got %d", len(mtx.TxIn))
}
op := mtx.TxIn[0].PreviousOutPoint
if !op.Hash.IsEqual(coins[1].Hash()) || op.Index != coins[1].Index() {
t.Errorf("Expected the second coin to be added as input to mtx")
}
}
// handleFundingReserveRequest processes a message intending to create, and
// validate a funding reservation request.
func (l *LightningWallet) handleFundingReserveRequest(req *initFundingReserveMsg) {
// Create a limbo and record entry for this newly pending funding request.
l.limboMtx.Lock()
id := l.nextFundingID
reservation := newChannelReservation(req.fundingType, req.fundingAmount, req.minFeeRate, l, id)
l.nextFundingID++
l.fundingLimbo[id] = reservation
l.limboMtx.Unlock()
// Grab the mutex on the ChannelReservation to ensure thead-safety
reservation.Lock()
defer reservation.Unlock()
reservation.partialState.TheirLNID = req.nodeID
ourContribution := reservation.ourContribution
ourContribution.CsvDelay = req.csvDelay
// We hold the coin select mutex while querying for outputs, and
// performing coin selection in order to avoid inadvertent double spends
// accross funding transactions.
// NOTE: we don't use defer her so we can properly release the lock
// when we encounter an error condition.
l.coinSelectMtx.Lock()
// Find all unlocked unspent outputs with greater than 6 confirmations.
maxConfs := int32(math.MaxInt32)
// TODO(roasbeef): make 6 a config paramter?
unspentOutputs, err := l.ListUnspent(6, maxConfs, nil)
if err != nil {
l.coinSelectMtx.Unlock()
req.err <- err
req.resp <- nil
return
}
// Convert the outputs to coins for coin selection below.
coins, err := outputsToCoins(unspentOutputs)
if err != nil {
l.coinSelectMtx.Unlock()
req.err <- err
req.resp <- nil
return
}
// Peform coin selection over our available, unlocked unspent outputs
// in order to find enough coins to meet the funding amount requirements.
//
// TODO(roasbeef): Should extend coinset with optimal coin selection
// heuristics for our use case.
// TODO(roasbeef): factor in fees..
// TODO(roasbeef): possibly integrate the fee prediction project? if
// results hold up...
// NOTE: this current selection assumes "priority" is still a thing.
selector := &coinset.MaxValueAgeCoinSelector{
MaxInputs: 10,
MinChangeAmount: 10000,
}
selectedCoins, err := selector.CoinSelect(req.fundingAmount, coins)
if err != nil {
l.coinSelectMtx.Unlock()
req.err <- err
req.resp <- nil
return
}
// Lock the selected coins. These coins are now "reserved", this
// prevents concurrent funding requests from referring to and this
// double-spending the same set of coins.
ourContribution.Inputs = make([]*wire.TxIn, len(selectedCoins.Coins()))
for i, coin := range selectedCoins.Coins() {
txout := wire.NewOutPoint(coin.Hash(), coin.Index())
l.LockOutpoint(*txout)
// Empty sig script, we'll actually sign if this reservation is
// queued up to be completed (the other side accepts).
outPoint := wire.NewOutPoint(coin.Hash(), coin.Index())
ourContribution.Inputs[i] = wire.NewTxIn(outPoint, nil)
}
l.coinSelectMtx.Unlock()
// Create some possibly neccessary change outputs.
selectedTotalValue := coinset.NewCoinSet(selectedCoins.Coins()).TotalValue()
if selectedTotalValue > req.fundingAmount {
ourContribution.ChangeOutputs = make([]*wire.TxOut, 1)
// Change is necessary. Query for an available change address to
// send the remainder to.
changeAddr, err := l.NewChangeAddress(waddrmgr.DefaultAccountNum)
if err != nil {
req.err <- err
req.resp <- nil
return
}
changeAddrScript, err := txscript.PayToAddrScript(changeAddr)
if err != nil {
req.err <- err
req.resp <- nil
return
}
changeAmount := selectedTotalValue - req.fundingAmount
ourContribution.ChangeOutputs[0] = wire.NewTxOut(int64(changeAmount),
changeAddrScript)
}
// TODO(roasbeef): re-calculate fees here to minFeePerKB, may need more inputs
// Grab two fresh keys from out HD chain, one will be used for the
// multi-sig funding transaction, and the other for the commitment
// transaction.
multiSigKey, err := l.getNextRawKey()
if err != nil {
req.err <- err
req.resp <- nil
return
}
commitKey, err := l.getNextRawKey()
if err != nil {
req.err <- err
req.resp <- nil
return
}
reservation.partialState.MultiSigKey = multiSigKey
ourContribution.MultiSigKey = multiSigKey.PubKey()
reservation.partialState.OurCommitKey = commitKey
ourContribution.CommitKey = commitKey.PubKey()
// Generate a fresh address to be used in the case of a cooperative
// channel close.
deliveryAddress, err := l.NewAddress(waddrmgr.DefaultAccountNum)
if err != nil {
req.err <- err
req.resp <- nil
return
}
reservation.partialState.OurDeliveryAddress = deliveryAddress
ourContribution.DeliveryAddress = deliveryAddress
// Create a new shaChain for verifiable transaction revocations. This
// will be used to generate revocation hashes for our past/current
// commitment transactions once we start to make payments within the
// channel.
shaChain, err := shachain.NewFromSeed(nil, 0)
if err != nil {
req.err <- err
req.resp <- nil
return
}
reservation.partialState.OurShaChain = shaChain
copy(ourContribution.RevocationHash[:], shaChain.CurrentRevocationHash())
// Funding reservation request succesfully handled. The funding inputs
// will be marked as unavailable until the reservation is either
// completed, or cancecled.
req.resp <- reservation
req.err <- nil
}