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lnwallet: add utils to generate HTLC scripts, split up commit output scripts

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This commit is contained in:
Olaoluwa Osuntokun 2015-12-31 00:32:09 -06:00
parent c41f7d1a7d
commit 41f4992218
2 changed files with 130 additions and 5 deletions
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5
lnwallet/channel.go
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@ -16,11 +16,6 @@ import (
const (
// TODO(roasbeef): make not random value
MaxPendingPayments = 10
// TODO(roasbeef): remove these and use the one's defined in txscript
// within testnet-L.
SequenceLockTimeSeconds = uint32(1 << 22)
SequenceLockTimeMask = uint32(0x0000ffff)
)
// LightningChannel...

130
lnwallet/script_utils.go
View File

@ -4,11 +4,20 @@ import (
"bytes"
"fmt"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
)
var (
// TODO(roasbeef): remove these and use the one's defined in txscript
// within testnet-L.
SequenceLockTimeSeconds = uint32(1 << 22)
SequenceLockTimeMask = uint32(0x0000ffff)
OP_CHECKSEQUENCEVERIFY byte = txscript.OP_NOP3
)
// scriptHashPkScript generates a pay-to-script-hash public key script paying
// to the hash160 of the passed redeem script.
func scriptHashPkScript(redeemScript []byte) ([]byte, error) {
@ -103,3 +112,124 @@ func findScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) {
return found, index
}
// senderHTLCScript...
func senderHTLCScript(absoluteTimeout, relativeTimeout uint32, senderKey,
receiverKey *btcec.PublicKey, revokeHash, paymentHash []byte) ([]byte, error) {
builder := txscript.NewScriptBuilder()
// Was the pre-image to the payment hash presented?
builder.AddOp(txscript.OP_HASH160)
builder.AddOp(txscript.OP_DUP)
builder.AddData(paymentHash)
builder.AddOp(txscript.OP_EQUAL)
// How about the pre-image for our commitment revocation hash?
builder.AddOp(txscript.OP_SWAP)
builder.AddData(revokeHash)
builder.AddOp(txscript.OP_EQUAL)
builder.AddOp(txscript.OP_SWAP)
builder.AddOp(txscript.OP_ADD)
// If either is present, then the receiver can claim immediately.
builder.AddOp(txscript.OP_IF)
builder.AddData(receiverKey.SerializeCompressed())
// Otherwise, we (the sender) need to wait for an absolute HTLC
// timeout, then afterwards a relative timeout before we claim re-claim
// the unsettled funds.
builder.AddOp(txscript.OP_ELSE)
builder.AddInt64(int64(absoluteTimeout))
builder.AddOp(txscript.OP_CHECKLOCKTIMEVERIFY)
builder.AddInt64(int64(relativeTimeout))
builder.AddOp(OP_CHECKSEQUENCEVERIFY)
builder.AddOp(txscript.OP_2DROP)
builder.AddData(senderKey.SerializeCompressed())
builder.AddOp(txscript.OP_ENDIF)
builder.AddOp(txscript.OP_CHECKSIG)
return builder.Script()
}
// receiverHTLCScript...
func receiverHTLCScript(absoluteTimeout, relativeTimeout uint32, senderKey,
receiverKey *btcec.PublicKey, revokeHash, paymentHash []byte) ([]byte, error) {
builder := txscript.NewScriptBuilder()
// Was the pre-image to the payment hash presented?
builder.AddOp(txscript.OP_HASH160)
builder.AddOp(txscript.OP_DUP)
builder.AddData(paymentHash)
builder.AddOp(txscript.OP_EQUAL)
builder.AddOp(txscript.OP_IF)
// If so, let the receiver redeem after a relative timeout.
builder.AddInt64(int64(relativeTimeout))
builder.AddOp(OP_CHECKSEQUENCEVERIFY)
builder.AddOp(txscript.OP_2DROP)
builder.AddData(receiverKey.SerializeCompressed())
// Otherwise, if the sender has the revocation pre-image to the
// receiver's commitment transactions, then let them claim the
// funds immediately.
builder.AddOp(txscript.OP_ELSE)
builder.AddData(revokeHash)
builder.AddOp(txscript.OP_EQUAL)
// If not, then the sender needs to wait for the HTLC timeout.
builder.AddOp(txscript.OP_NOTIF)
builder.AddInt64(int64(absoluteTimeout))
builder.AddOp(OP_CHECKSEQUENCEVERIFY)
builder.AddOp(txscript.OP_DROP)
builder.AddOp(txscript.OP_ENDIF)
builder.AddData(senderKey.SerializeCompressed())
builder.AddOp(txscript.OP_ENDIF)
builder.AddOp(txscript.OP_CHECKSIG)
return builder.Script()
}
// commitScriptToSelf...
func commitScriptToSelf(csvTimeout uint32, selfKey, theirKey *btcec.PublicKey, revokeHash []byte) ([]byte, error) {
// This script is spendable under two conditions: either the 'csvTimeout'
// has passed and we can redeem our funds, or they have the pre-image
// to 'revokeHash'.
builder := txscript.NewScriptBuilder()
// If the pre-image for the revocation hash is presented, then allow a
// spend provided the proper signature.
builder.AddOp(txscript.OP_HASH160)
builder.AddData(revokeHash)
builder.AddOp(txscript.OP_EQUAL)
builder.AddOp(txscript.OP_IF)
builder.AddData(theirKey.SerializeCompressed())
builder.AddOp(txscript.OP_ELSE)
// Otherwise, we can re-claim our funds after a CSV delay of
// 'csvTimeout' timeout blocks, and a valid signature.
builder.AddInt64(int64(csvTimeout))
builder.AddOp(OP_CHECKSEQUENCEVERIFY)
builder.AddOp(txscript.OP_DROP)
builder.AddData(selfKey.SerializeCompressed())
builder.AddOp(txscript.OP_ENDIF)
builder.AddOp(txscript.OP_CHECKSIG)
return builder.Script()
}
// commitScriptUnencumbered...
func commitScriptUnencumbered(key *btcec.PublicKey) ([]byte, error) {
// This script goes to the "other" party, and it spendable immediately.
builder := txscript.NewScriptBuilder()
builder.AddOp(txscript.OP_DUP)
builder.AddOp(txscript.OP_HASH160)
builder.AddData(btcutil.Hash160(key.SerializeCompressed()))
builder.AddOp(txscript.OP_EQUALVERIFY)
builder.AddOp(txscript.OP_CHECKSIG)
return builder.Script()
}