+
+impl_writeable_tlv_based!(CommitmentTransaction, {
+ (0, commitment_number, required),
+ (2, to_broadcaster_value_sat, required),
+ (4, to_countersignatory_value_sat, required),
+ (6, feerate_per_kw, required),
+ (8, keys, required),
+ (10, built, required),
+ (12, htlcs, vec_type),
+ (14, opt_anchors, option),
+});
+
+impl CommitmentTransaction {
+ /// Construct an object of the class while assigning transaction output indices to HTLCs.
+ ///
+ /// Populates HTLCOutputInCommitment.transaction_output_index in htlcs_with_aux.
+ ///
+ /// The generic T allows the caller to match the HTLC output index with auxiliary data.
+ /// This auxiliary data is not stored in this object.
+ ///
+ /// Only include HTLCs that are above the dust limit for the channel.
+ ///
+ /// (C-not exported) due to the generic though we likely should expose a version without
+ pub fn new_with_auxiliary_htlc_data<T>(commitment_number: u64, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, opt_anchors: bool, broadcaster_funding_key: PublicKey, countersignatory_funding_key: PublicKey, keys: TxCreationKeys, feerate_per_kw: u32, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters) -> CommitmentTransaction {
+ // Sort outputs and populate output indices while keeping track of the auxiliary data
+ let (outputs, htlcs) = Self::internal_build_outputs(&keys, to_broadcaster_value_sat, to_countersignatory_value_sat, htlcs_with_aux, channel_parameters, opt_anchors, &broadcaster_funding_key, &countersignatory_funding_key).unwrap();
+
+ let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(commitment_number, channel_parameters);
+ let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
+ let txid = transaction.txid();
+ CommitmentTransaction {
+ commitment_number,
+ to_broadcaster_value_sat,
+ to_countersignatory_value_sat,
+ feerate_per_kw,
+ htlcs,
+ opt_anchors: if opt_anchors { Some(()) } else { None },
+ keys,
+ built: BuiltCommitmentTransaction {
+ transaction,
+ txid
+ },
+ }
+ }
+
+ fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_funding_key: &PublicKey, countersignatory_funding_key: &PublicKey) -> Result<BuiltCommitmentTransaction, ()> {
+ let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(self.commitment_number, channel_parameters);
+
+ let mut htlcs_with_aux = self.htlcs.iter().map(|h| (h.clone(), ())).collect();
+ let (outputs, _) = Self::internal_build_outputs(keys, self.to_broadcaster_value_sat, self.to_countersignatory_value_sat, &mut htlcs_with_aux, channel_parameters, self.opt_anchors.is_some(), broadcaster_funding_key, countersignatory_funding_key)?;
+
+ let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
+ let txid = transaction.txid();
+ let built_transaction = BuiltCommitmentTransaction {
+ transaction,
+ txid
+ };
+ Ok(built_transaction)
+ }
+
+ fn make_transaction(obscured_commitment_transaction_number: u64, txins: Vec<TxIn>, outputs: Vec<TxOut>) -> Transaction {
+ Transaction {
+ version: 2,
+ lock_time: ((0x20 as u32) << 8 * 3) | ((obscured_commitment_transaction_number & 0xffffffu64) as u32),
+ input: txins,
+ output: outputs,
+ }
+ }
+
+ // This is used in two cases:
+ // - initial sorting of outputs / HTLCs in the constructor, in which case T is auxiliary data the
+ // caller needs to have sorted together with the HTLCs so it can keep track of the output index
+ // - building of a bitcoin transaction during a verify() call, in which case T is just ()
+ fn internal_build_outputs<T>(keys: &TxCreationKeys, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters, opt_anchors: bool, broadcaster_funding_key: &PublicKey, countersignatory_funding_key: &PublicKey) -> Result<(Vec<TxOut>, Vec<HTLCOutputInCommitment>), ()> {
+ let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
+ let contest_delay = channel_parameters.contest_delay();
+
+ let mut txouts: Vec<(TxOut, Option<&mut HTLCOutputInCommitment>)> = Vec::new();
+
+ if to_countersignatory_value_sat > 0 {
+ let script = script_for_p2wpkh(&countersignatory_pubkeys.payment_point);
+ txouts.push((
+ TxOut {
+ script_pubkey: script.clone(),
+ value: to_countersignatory_value_sat,
+ },
+ None,
+ ))
+ }
+
+ if to_broadcaster_value_sat > 0 {
+ let redeem_script = get_revokeable_redeemscript(
+ &keys.revocation_key,
+ contest_delay,
+ &keys.broadcaster_delayed_payment_key,
+ );
+ txouts.push((
+ TxOut {
+ script_pubkey: redeem_script.to_v0_p2wsh(),
+ value: to_broadcaster_value_sat,
+ },
+ None,
+ ));
+ }
+
+ if opt_anchors {
+ if to_broadcaster_value_sat > 0 || !htlcs_with_aux.is_empty() {
+ let anchor_script = get_anchor_redeemscript(broadcaster_funding_key);
+ txouts.push((
+ TxOut {
+ script_pubkey: anchor_script.to_v0_p2wsh(),
+ value: ANCHOR_OUTPUT_VALUE_SATOSHI,
+ },
+ None,
+ ));
+ }
+
+ if to_countersignatory_value_sat > 0 || !htlcs_with_aux.is_empty() {
+ let anchor_script = get_anchor_redeemscript(countersignatory_funding_key);
+ txouts.push((
+ TxOut {
+ script_pubkey: anchor_script.to_v0_p2wsh(),
+ value: ANCHOR_OUTPUT_VALUE_SATOSHI,
+ },
+ None,
+ ));