multi: add p2tr keyspend wallet support

cmd/lncli/commands.go

@@ -139,7 +139,8 @@ var newAddressCommand = cli.Command{
 	Description: `
 	Generate a wallet new address. Address-types has to be one of:
 	    - p2wkh:  Pay to witness key hash
-	    - np2wkh: Pay to nested witness key hash`,
+	    - np2wkh: Pay to nested witness key hash
+	    - p2tr:   Pay to taproot pubkey`,
 	Action: actionDecorator(newAddress),
 }
 
@@ -161,6 +162,8 @@ func newAddress(ctx *cli.Context) error {
 		addrType = lnrpc.AddressType_WITNESS_PUBKEY_HASH
 	case "np2wkh":
 		addrType = lnrpc.AddressType_NESTED_PUBKEY_HASH
+	case "p2tr":
+		addrType = lnrpc.AddressType_TAPROOT_PUBKEY
 	default:
 		return fmt.Errorf("invalid address type %v, support address type "+
 			"are: p2wkh and np2wkh", stringAddrType)

config_builder.go

@@ -1112,7 +1112,14 @@ func importWatchOnlyAccounts(wallet *wallet.Wallet,
 
 	for _, scope := range scopes {
 		addrSchema := waddrmgr.ScopeAddrMap[waddrmgr.KeyScopeBIP0084]
-		if scope.Scope.Purpose == waddrmgr.KeyScopeBIP0049Plus.Purpose {
+
+		// We want witness pubkey hash by default, except for BIP49
+		// where we want mixed and BIP86 where we want taproot address
+		// formats.
+		switch scope.Scope.Purpose {
+		case waddrmgr.KeyScopeBIP0049Plus.Purpose,
+			waddrmgr.KeyScopeBIP0086.Purpose:
+
 			addrSchema = waddrmgr.ScopeAddrMap[scope.Scope]
 		}
 

input/size.go

@@ -77,6 +77,18 @@ const (
 	//      - pkscript (p2sh): 23 bytes
 	P2SHOutputSize = 8 + 1 + P2SHSize
 
+	// P2TRSize 34 bytes
+	//	- OP_0: 1 byte
+	//	- OP_DATA: 1 byte (x-only public key length)
+	//	- x-only public key length: 32 bytes
+	P2TRSize = 34
+
+	// P2TROutputSize 43 bytes
+	//      - value: 8 bytes
+	//      - var_int: 1 byte (pkscript_length)
+	//      - pkscript (p2tr): 34 bytes
+	P2TROutputSize = 8 + 1 + P2TRSize
+
 	// P2PKHScriptSigSize 108 bytes
 	//      - OP_DATA: 1 byte (signature length)
 	//      - signature
@@ -519,6 +531,19 @@ const (
 	//      - witness_script_length: 1 byte
 	//      - witness_script (anchor_script)
 	AnchorWitnessSize = 1 + 1 + 73 + 1 + AnchorScriptSize
+
+	// TaprootKeyPathWitnessSize 66 bytes
+	//	- NumberOfWitnessElements: 1 byte
+	//	- sigLength: 1 byte
+	//	- sig: 64 bytes
+	TaprootKeyPathWitnessSize = 1 + 1 + 64
+
+	// TaprootKeyPathCustomSighashWitnessSize 67 bytes
+	//	- NumberOfWitnessElements: 1 byte
+	//	- sigLength: 1 byte
+	//	- sig: 64 bytes
+	//      - sighashFlag: 1 byte
+	TaprootKeyPathCustomSighashWitnessSize = TaprootKeyPathWitnessSize + 1
 )
 
 // EstimateCommitTxWeight estimate commitment transaction weight depending on
@@ -639,6 +664,15 @@ func (twe *TxWeightEstimator) AddP2WSHOutput() *TxWeightEstimator {
 	return twe
 }
 
+// AddP2TROutput updates the weight estimate to account for an additional native
+// SegWit v1 P2TR output.
+func (twe *TxWeightEstimator) AddP2TROutput() *TxWeightEstimator {
+	twe.outputSize += P2TROutputSize
+	twe.outputCount++
+
+	return twe
+}
+
 // AddP2SHOutput updates the weight estimate to account for an additional P2SH
 // output.
 func (twe *TxWeightEstimator) AddP2SHOutput() *TxWeightEstimator {

input/witnessgen.go

@@ -175,6 +175,11 @@ const (
 	// and CLTV locktime as part of the script enforced lease commitment
 	// type.
 	LeaseHtlcAcceptedSuccessSecondLevel StandardWitnessType = 20
+
+	// TaprootPubKeySpend is a witness type that allows us to spend a
+	// regular p2tr output that's sent to an output which is under complete
+	// control of the backing wallet.
+	TaprootPubKeySpend StandardWitnessType = 21
 )
 
 // String returns a human readable version of the target WitnessType.
@@ -245,6 +250,9 @@ func (wt StandardWitnessType) String() string {
 	case LeaseHtlcAcceptedSuccessSecondLevel:
 		return "LeaseHtlcAcceptedSuccessSecondLevel"
 
+	case TaprootPubKeySpend:
+		return "TaprootPubKeySpend"
+
 	default:
 		return fmt.Sprintf("Unknown WitnessType: %v", uint32(wt))
 	}
@@ -388,6 +396,8 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 
 		case WitnessKeyHash:
 			fallthrough
+		case TaprootPubKeySpend:
+			fallthrough
 		case NestedWitnessKeyHash:
 			return signer.ComputeInputScript(tx, desc)
 
@@ -494,6 +504,9 @@ func (wt StandardWitnessType) SizeUpperBound() (int, bool, error) {
 	// The revocation output of a second level output of an HTLC.
 	case HtlcSecondLevelRevoke:
 		return ToLocalPenaltyWitnessSize, false, nil
+
+	case TaprootPubKeySpend:
+		return TaprootKeyPathCustomSighashWitnessSize, false, nil
 	}
 
 	return 0, false, fmt.Errorf("unexpected witness type: %v", wt)

lnrpc/lightning.proto

@@ -1138,12 +1138,15 @@ message ListUnspentResponse {
 
 - `p2wkh`: Pay to witness key hash (`WITNESS_PUBKEY_HASH` = 0)
 - `np2wkh`: Pay to nested witness key hash (`NESTED_PUBKEY_HASH` = 1)
+- `p2tr`: Pay to taproot pubkey (`TAPROOT_PUBKEY` = 4)
 */
 enum AddressType {
     WITNESS_PUBKEY_HASH = 0;
     NESTED_PUBKEY_HASH = 1;
     UNUSED_WITNESS_PUBKEY_HASH = 2;
     UNUSED_NESTED_PUBKEY_HASH = 3;
+    TAPROOT_PUBKEY = 4;
+    UNUSED_TAPROOT_PUBKEY = 5;
 }
 
 message NewAddressRequest {

lnrpc/lightning.swagger.json

@@ -1801,7 +1801,9 @@
               "WITNESS_PUBKEY_HASH",
               "NESTED_PUBKEY_HASH",
               "UNUSED_WITNESS_PUBKEY_HASH",
-              "UNUSED_NESTED_PUBKEY_HASH"
+              "UNUSED_NESTED_PUBKEY_HASH",
+              "TAPROOT_PUBKEY",
+              "UNUSED_TAPROOT_PUBKEY"
             ],
             "default": "WITNESS_PUBKEY_HASH"
           },
@@ -2923,10 +2925,12 @@
         "WITNESS_PUBKEY_HASH",
         "NESTED_PUBKEY_HASH",
         "UNUSED_WITNESS_PUBKEY_HASH",
-        "UNUSED_NESTED_PUBKEY_HASH"
+        "UNUSED_NESTED_PUBKEY_HASH",
+        "TAPROOT_PUBKEY",
+        "UNUSED_TAPROOT_PUBKEY"
       ],
       "default": "WITNESS_PUBKEY_HASH",
-      "description": "- `p2wkh`: Pay to witness key hash (`WITNESS_PUBKEY_HASH` = 0)\n- `np2wkh`: Pay to nested witness key hash (`NESTED_PUBKEY_HASH` = 1)",
+      "description": "- `p2wkh`: Pay to witness key hash (`WITNESS_PUBKEY_HASH` = 0)\n- `np2wkh`: Pay to nested witness key hash (`NESTED_PUBKEY_HASH` = 1)\n- `p2tr`: Pay to taproot pubkey (`TAPROOT_PUBKEY` = 4)",
       "title": "`AddressType` has to be one of:"
     },
     "lnrpcAmount": {

lnrpc/marshall_utils.go

@@ -94,6 +94,9 @@ func MarshalUtxos(utxos []*lnwallet.Utxo, activeNetParams *chaincfg.Params) (
 		case lnwallet.NestedWitnessPubKey:
 			addrType = AddressType_NESTED_PUBKEY_HASH
 
+		case lnwallet.TaprootPubkey:
+			addrType = AddressType_TAPROOT_PUBKEY
+
 		case lnwallet.UnknownAddressType:
 			continue