a0e54a9650
This commit fixes the to-local-witness estimate to use the correct witness size estimate for anchor channels. We retain the off-by-one bug from the original constant otherwise.
372 lines
11 KiB
Go
372 lines
11 KiB
Go
package lookout_test
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import (
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"testing"
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"time"
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"github.com/btcsuite/btcd/blockchain"
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"github.com/btcsuite/btcd/btcec"
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"github.com/btcsuite/btcd/txscript"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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"github.com/btcsuite/btcutil/txsort"
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"github.com/lightningnetwork/lnd/input"
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"github.com/lightningnetwork/lnd/keychain"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/watchtower/blob"
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"github.com/lightningnetwork/lnd/watchtower/lookout"
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"github.com/lightningnetwork/lnd/watchtower/wtdb"
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"github.com/lightningnetwork/lnd/watchtower/wtmock"
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"github.com/lightningnetwork/lnd/watchtower/wtpolicy"
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"github.com/stretchr/testify/require"
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)
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const csvDelay uint32 = 144
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var (
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revPrivBytes = []byte{
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0x8f, 0x4b, 0x51, 0x83, 0xa9, 0x34, 0xbd, 0x5f,
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0x74, 0x6c, 0x9d, 0x5c, 0xae, 0x88, 0x2d, 0x31,
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0x06, 0x90, 0xdd, 0x8c, 0x9b, 0x31, 0xbc, 0xd1,
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0x78, 0x91, 0x88, 0x2a, 0xf9, 0x74, 0xa0, 0xef,
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}
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toLocalPrivBytes = []byte{
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0xde, 0x17, 0xc1, 0x2f, 0xdc, 0x1b, 0xc0, 0xc6,
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0x59, 0x5d, 0xf9, 0xc1, 0x3e, 0x89, 0xbc, 0x6f,
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0x01, 0x85, 0x45, 0x76, 0x26, 0xce, 0x9c, 0x55,
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0x3b, 0xc9, 0xec, 0x3d, 0xd8, 0x8b, 0xac, 0xa8,
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}
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toRemotePrivBytes = []byte{
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0x28, 0x59, 0x6f, 0x36, 0xb8, 0x9f, 0x19, 0x5d,
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0xcb, 0x07, 0x48, 0x8a, 0xe5, 0x89, 0x71, 0x74,
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0x70, 0x4c, 0xff, 0x1e, 0x9c, 0x00, 0x93, 0xbe,
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0xe2, 0x2e, 0x68, 0x08, 0x4c, 0xb4, 0x0f, 0x4f,
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}
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rewardCommitType = blob.TypeFromFlags(
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blob.FlagReward, blob.FlagCommitOutputs,
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)
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altruistCommitType = blob.FlagCommitOutputs.Type()
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altruistAnchorCommitType = blob.TypeAltruistAnchorCommit
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)
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// TestJusticeDescriptor asserts that a JusticeDescriptor is able to produce the
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// correct justice transaction for different blob types.
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func TestJusticeDescriptor(t *testing.T) {
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tests := []struct {
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name string
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blobType blob.Type
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}{
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{
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name: "reward and commit type",
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blobType: rewardCommitType,
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},
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{
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name: "altruist and commit type",
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blobType: altruistCommitType,
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},
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{
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name: "altruist anchor commit type",
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blobType: altruistAnchorCommitType,
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},
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}
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for _, test := range tests {
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t.Run(test.name, func(t *testing.T) {
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testJusticeDescriptor(t, test.blobType)
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})
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}
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}
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func testJusticeDescriptor(t *testing.T, blobType blob.Type) {
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isAnchorChannel := blobType.IsAnchorChannel()
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const (
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localAmount = btcutil.Amount(100000)
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remoteAmount = btcutil.Amount(200000)
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totalAmount = localAmount + remoteAmount
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)
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// Parse the key pairs for all keys used in the test.
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revSK, revPK := btcec.PrivKeyFromBytes(
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btcec.S256(), revPrivBytes,
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)
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_, toLocalPK := btcec.PrivKeyFromBytes(
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btcec.S256(), toLocalPrivBytes,
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)
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toRemoteSK, toRemotePK := btcec.PrivKeyFromBytes(
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btcec.S256(), toRemotePrivBytes,
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)
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// Create the signer, and add the revocation and to-remote privkeys.
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signer := wtmock.NewMockSigner()
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var (
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revKeyLoc = signer.AddPrivKey(revSK)
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toRemoteKeyLoc = signer.AddPrivKey(toRemoteSK)
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)
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// Construct the to-local witness script.
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toLocalScript, err := input.CommitScriptToSelf(
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csvDelay, toLocalPK, revPK,
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)
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require.Nil(t, err)
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// Compute the to-local witness script hash.
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toLocalScriptHash, err := input.WitnessScriptHash(toLocalScript)
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require.Nil(t, err)
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// Compute the to-remote redeem script, witness script hash, and
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// sequence numbers.
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//
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// NOTE: This is pretty subtle.
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//
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// The actual redeem script for a p2wkh output is just the pubkey, but
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// the witness sighash calculation injects the classic p2kh script:
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// OP_DUP OP_HASH160 <pubkey-hash160> OP_EQUALVERIFY OP_CHECKSIG. When
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// signing for p2wkh we don't pass the raw pubkey as the witness script
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// to the sign descriptor (since that's also not a valid script).
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// Instead we give it the _pkscript_ of the form OP_0 <pubkey-hash160>
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// from which pubkey-hash160 is extracted during sighash calculation.
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//
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// On the other hand, signing for the anchor p2wsh to-remote outputs
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// requires the sign descriptor to contain the redeem script ver batim.
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// This difference in behavior forces us to use a distinct
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// toRemoteSigningScript to handle both cases.
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var (
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toRemoteSequence uint32
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toRemoteRedeemScript []byte
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toRemoteScriptHash []byte
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toRemoteSigningScript []byte
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)
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if isAnchorChannel {
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toRemoteSequence = 1
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toRemoteRedeemScript, err = input.CommitScriptToRemoteConfirmed(
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toRemotePK,
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)
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require.Nil(t, err)
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toRemoteScriptHash, err = input.WitnessScriptHash(
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toRemoteRedeemScript,
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)
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require.Nil(t, err)
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// As it should be.
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toRemoteSigningScript = toRemoteRedeemScript
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} else {
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toRemoteRedeemScript = toRemotePK.SerializeCompressed()
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toRemoteScriptHash, err = input.CommitScriptUnencumbered(
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toRemotePK,
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)
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require.Nil(t, err)
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// NOTE: This is the _pkscript_.
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toRemoteSigningScript = toRemoteScriptHash
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}
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// Construct the breaching commitment txn, containing the to-local and
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// to-remote outputs. We don't need any inputs for this test.
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breachTxn := &wire.MsgTx{
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Version: 2,
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TxIn: []*wire.TxIn{},
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TxOut: []*wire.TxOut{
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{
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Value: int64(localAmount),
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PkScript: toLocalScriptHash,
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},
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{
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Value: int64(remoteAmount),
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PkScript: toRemoteScriptHash,
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},
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},
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}
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breachTxID := breachTxn.TxHash()
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// Compute the weight estimate for our justice transaction.
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var weightEstimate input.TxWeightEstimator
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// An older ToLocalPenaltyWitnessSize constant used to underestimate the
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// size by one byte. The diferrence in weight can cause different output
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// values on the sweep transaction, so we mimic the original bug and
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// create signatures using the original weight estimate. For anchor
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// channels we fix this and use the correct witness size.
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if isAnchorChannel {
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weightEstimate.AddWitnessInput(input.ToLocalPenaltyWitnessSize)
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} else {
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weightEstimate.AddWitnessInput(input.ToLocalPenaltyWitnessSize - 1)
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}
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if isAnchorChannel {
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weightEstimate.AddWitnessInput(input.ToRemoteConfirmedWitnessSize)
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} else {
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weightEstimate.AddWitnessInput(input.P2WKHWitnessSize)
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}
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weightEstimate.AddP2WKHOutput()
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if blobType.Has(blob.FlagReward) {
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weightEstimate.AddP2WKHOutput()
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}
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txWeight := weightEstimate.Weight()
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// Create a session info so that simulate agreement of the sweep
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// parameters that should be used in constructing the justice
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// transaction.
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policy := wtpolicy.Policy{
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TxPolicy: wtpolicy.TxPolicy{
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BlobType: blobType,
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SweepFeeRate: 2000,
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RewardRate: 900000,
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},
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}
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sessionInfo := &wtdb.SessionInfo{
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Policy: policy,
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RewardAddress: makeAddrSlice(22),
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}
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// Begin to assemble the justice kit, starting with the sweep address,
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// pubkeys, and csv delay.
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justiceKit := &blob.JusticeKit{
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BlobType: blobType,
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SweepAddress: makeAddrSlice(22),
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CSVDelay: csvDelay,
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}
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copy(justiceKit.RevocationPubKey[:], revPK.SerializeCompressed())
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copy(justiceKit.LocalDelayPubKey[:], toLocalPK.SerializeCompressed())
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copy(justiceKit.CommitToRemotePubKey[:], toRemotePK.SerializeCompressed())
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// Create a transaction spending from the outputs of the breach
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// transaction created earlier. The inputs are always ordered w/
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// to-local and then to-remote. The outputs are always added as the
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// sweep address then reward address.
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justiceTxn := &wire.MsgTx{
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Version: 2,
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TxIn: []*wire.TxIn{
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{
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PreviousOutPoint: wire.OutPoint{
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Hash: breachTxID,
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Index: 0,
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},
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},
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{
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PreviousOutPoint: wire.OutPoint{
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Hash: breachTxID,
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Index: 1,
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},
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Sequence: toRemoteSequence,
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},
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},
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}
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outputs, err := policy.ComputeJusticeTxOuts(
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totalAmount, int64(txWeight), justiceKit.SweepAddress,
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sessionInfo.RewardAddress,
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)
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require.Nil(t, err)
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// Attach the txouts and BIP69 sort the resulting transaction.
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justiceTxn.TxOut = outputs
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txsort.InPlaceSort(justiceTxn)
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hashCache := txscript.NewTxSigHashes(justiceTxn)
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// Create the sign descriptor used to sign for the to-local input.
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toLocalSignDesc := &input.SignDescriptor{
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KeyDesc: keychain.KeyDescriptor{
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KeyLocator: revKeyLoc,
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},
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WitnessScript: toLocalScript,
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Output: breachTxn.TxOut[0],
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SigHashes: hashCache,
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InputIndex: 0,
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HashType: txscript.SigHashAll,
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}
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// Create the sign descriptor used to sign for the to-remote input.
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toRemoteSignDesc := &input.SignDescriptor{
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KeyDesc: keychain.KeyDescriptor{
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KeyLocator: toRemoteKeyLoc,
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PubKey: toRemotePK,
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},
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WitnessScript: toRemoteSigningScript,
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Output: breachTxn.TxOut[1],
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SigHashes: hashCache,
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InputIndex: 1,
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HashType: txscript.SigHashAll,
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}
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// Verify that our test justice transaction is sane.
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btx := btcutil.NewTx(justiceTxn)
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err = blockchain.CheckTransactionSanity(btx)
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require.Nil(t, err)
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// Compute a DER-encoded signature for the to-local input.
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toLocalSigRaw, err := signer.SignOutputRaw(justiceTxn, toLocalSignDesc)
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require.Nil(t, err)
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// Compute the witness for the to-remote input. The first element is a
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// DER-encoded signature under the to-remote pubkey. The sighash flag is
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// also present, so we trim it.
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toRemoteSigRaw, err := signer.SignOutputRaw(justiceTxn, toRemoteSignDesc)
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require.Nil(t, err)
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// Convert the DER to-local sig into a fixed-size signature.
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toLocalSig, err := lnwire.NewSigFromSignature(toLocalSigRaw)
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require.Nil(t, err)
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// Convert the DER to-remote sig into a fixed-size signature.
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toRemoteSig, err := lnwire.NewSigFromSignature(toRemoteSigRaw)
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require.Nil(t, err)
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// Complete our justice kit by copying the signatures into the payload.
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copy(justiceKit.CommitToLocalSig[:], toLocalSig[:])
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copy(justiceKit.CommitToRemoteSig[:], toRemoteSig[:])
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justiceDesc := &lookout.JusticeDescriptor{
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BreachedCommitTx: breachTxn,
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SessionInfo: sessionInfo,
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JusticeKit: justiceKit,
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}
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// Construct a breach punisher that will feed published transactions
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// over the buffered channel.
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publications := make(chan *wire.MsgTx, 1)
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punisher := lookout.NewBreachPunisher(&lookout.PunisherConfig{
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PublishTx: func(tx *wire.MsgTx, _ string) error {
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publications <- tx
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return nil
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},
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})
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// Exact retribution on the offender. If no error is returned, we expect
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// the justice transaction to be published via the channel.
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err = punisher.Punish(justiceDesc, nil)
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require.Nil(t, err)
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// Retrieve the published justice transaction.
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var wtJusticeTxn *wire.MsgTx
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select {
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case wtJusticeTxn = <-publications:
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case <-time.After(50 * time.Millisecond):
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t.Fatalf("punisher did not publish justice txn")
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}
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// Construct the test's to-local witness.
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justiceTxn.TxIn[0].Witness = make([][]byte, 3)
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justiceTxn.TxIn[0].Witness[0] = append(toLocalSigRaw.Serialize(),
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byte(txscript.SigHashAll))
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justiceTxn.TxIn[0].Witness[1] = []byte{1}
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justiceTxn.TxIn[0].Witness[2] = toLocalScript
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// Construct the test's to-remote witness.
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justiceTxn.TxIn[1].Witness = make([][]byte, 2)
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justiceTxn.TxIn[1].Witness[0] = append(toRemoteSigRaw.Serialize(),
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byte(txscript.SigHashAll))
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justiceTxn.TxIn[1].Witness[1] = toRemoteRedeemScript
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// Assert that the watchtower derives the same justice txn.
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require.Equal(t, justiceTxn, wtJusticeTxn)
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}
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