106 lines
3.0 KiB
Go
106 lines
3.0 KiB
Go
package lnwallet
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import (
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"bytes"
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"fmt"
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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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)
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// scriptHashPkScript generates a pay-to-script-hash public key script paying
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// to the hash160 of the passed redeem script.
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func scriptHashPkScript(redeemScript []byte) ([]byte, error) {
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bldr := txscript.NewScriptBuilder()
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bldr.AddOp(txscript.OP_HASH160)
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bldr.AddData(btcutil.Hash160(redeemScript))
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bldr.AddOp(txscript.OP_EQUAL)
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return bldr.Script()
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}
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// getFundingPkScript generates the non-p2sh'd multisig script for 2 of 2
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// pubkeys.
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func genFundingPkScript(aPub, bPub []byte) ([]byte, error) {
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if len(aPub) != 33 || len(bPub) != 33 {
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return nil, fmt.Errorf("Pubkey size error. Compressed pubkeys only")
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}
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// Swap to sort pubkeys if needed. Keys are sorted in lexicographical
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// order. The signatures within the scriptSig must also adhere to the
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// order, ensuring that the signatures for each public key appears
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// in the proper order on the stack.
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if bytes.Compare(aPub, bPub) == -1 {
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aPub, bPub = bPub, aPub
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}
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bldr := txscript.NewScriptBuilder()
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bldr.AddOp(txscript.OP_2)
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bldr.AddData(aPub) // Add both pubkeys (sorted).
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bldr.AddData(bPub)
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bldr.AddOp(txscript.OP_2)
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bldr.AddOp(txscript.OP_CHECKMULTISIG)
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return bldr.Script()
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}
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// fundMultiSigOut create the redeemScript for the funding transaction, and
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// also a TxOut paying to the p2sh of the multi-sig redeemScript. Give it the
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// two pubkeys and it'll give you the p2sh'd txout. You don't have to remember
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// the p2sh preimage, as long as you remember the pubkeys involved.
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func fundMultiSigOut(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error) {
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if amt < 0 {
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return nil, nil, fmt.Errorf("can't create FundTx script with " +
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"negative coins")
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}
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// p2shify
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redeemScript, err := genFundingPkScript(aPub, bPub)
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if err != nil {
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return nil, nil, err
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}
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pkScript, err := scriptHashPkScript(redeemScript)
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if err != nil {
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return nil, nil, err
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}
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return redeemScript, wire.NewTxOut(amt, pkScript), nil
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}
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// spendMultiSig generates the scriptSig required to redeem the 2-of-2 p2sh
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// multi-sig output.
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func spendMultiSig(redeemScript, sigA, sigB []byte) ([]byte, error) {
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bldr := txscript.NewScriptBuilder()
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// add a 0 for some multisig fun
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bldr.AddOp(txscript.OP_0)
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// add sigA
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bldr.AddData(sigA)
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// add sigB
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bldr.AddData(sigB)
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// preimage goes on AT THE ENDDDD
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bldr.AddData(redeemScript)
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// that's all, get bytes
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return bldr.Script()
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}
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// findScriptOutputIndex finds the index of the public key script output
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// matching 'script'. Additionally, a boolean is returned indicating if
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// a matching output was found at all.
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// NOTE: The search stops after the first matching script is found.
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func findScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) {
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found := false
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index := uint32(0)
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for i, txOut := range tx.TxOut {
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if bytes.Equal(txOut.PkScript, script) {
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found = true
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index = uint32(i)
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break
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}
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}
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return found, index
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}
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