From 6b1afcc313b2f031e568b695cd83fc53c18abd4c Mon Sep 17 00:00:00 2001
From: Antoine Riard <ariard@student.42.fr>
Date: Mon, 23 Mar 2020 21:22:14 -0400
Subject: [PATCH] Cache remote basepoint and remote_csv in new
 OnchainTxHandler::RemoteTxCache

Used in next commits to avoid passing script between ChannelMonitor
and OnchainTxHandler. ChannelMonitor duplicata will be removed
in future commits.
---
 lightning/src/ln/channelmonitor.rs |  6 ++---
 lightning/src/ln/onchaintx.rs      | 35 +++++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/lightning/src/ln/channelmonitor.rs b/lightning/src/ln/channelmonitor.rs
index ff0b6e9e..6f00392c 100644
--- a/lightning/src/ln/channelmonitor.rs
+++ b/lightning/src/ln/channelmonitor.rs
@@ -1053,7 +1053,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 		let payment_key_hash = WPubkeyHash::hash(&keys.pubkeys().payment_point.serialize());
 		let remote_payment_script = Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&payment_key_hash[..]).into_script();
 
-		let mut onchain_tx_handler = OnchainTxHandler::new(destination_script.clone(), keys.clone(), their_to_self_delay);
+		let mut onchain_tx_handler = OnchainTxHandler::new(destination_script.clone(), keys.clone(), their_to_self_delay, their_delayed_payment_base_key.clone(), their_htlc_base_key.clone(), our_to_self_delay);
 
 		let local_tx_sequence = initial_local_commitment_tx.unsigned_tx.input[0].sequence as u64;
 		let local_tx_locktime = initial_local_commitment_tx.unsigned_tx.lock_time as u64;
@@ -1088,8 +1088,8 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 			current_remote_commitment_txid: None,
 			prev_remote_commitment_txid: None,
 
-			their_htlc_base_key: their_htlc_base_key.clone(),
-			their_delayed_payment_base_key: their_delayed_payment_base_key.clone(),
+			their_htlc_base_key: *their_htlc_base_key,
+			their_delayed_payment_base_key: *their_delayed_payment_base_key,
 			funding_redeemscript,
 			channel_value_satoshis: channel_value_satoshis,
 			their_cur_revocation_points: None,
diff --git a/lightning/src/ln/onchaintx.rs b/lightning/src/ln/onchaintx.rs
index f263ddf4..eb30f155 100644
--- a/lightning/src/ln/onchaintx.rs
+++ b/lightning/src/ln/onchaintx.rs
@@ -12,6 +12,7 @@ use bitcoin::hash_types::Txid;
 
 use bitcoin::secp256k1::{Secp256k1, Signature};
 use bitcoin::secp256k1;
+use bitcoin::secp256k1::key::PublicKey;
 
 use ln::msgs::DecodeError;
 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
@@ -47,6 +48,13 @@ enum OnchainEvent {
 	}
 }
 
+/// Cache remote basepoint to compute any transaction on
+/// remote outputs, either justice or preimage/timeout transactions.
+struct RemoteTxCache {
+	remote_delayed_payment_base_key: PublicKey,
+	remote_htlc_base_key: PublicKey
+}
+
 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
 #[derive(Clone, PartialEq)]
 pub struct ClaimTxBumpMaterial {
@@ -194,6 +202,8 @@ pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 	prev_local_commitment: Option<LocalCommitmentTransaction>,
 	prev_local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 	local_csv: u16,
+	remote_tx_cache: RemoteTxCache,
+	remote_csv: u16,
 
 	key_storage: ChanSigner,
 
@@ -239,6 +249,10 @@ impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 
 		self.local_csv.write(writer)?;
 
+		self.remote_tx_cache.remote_delayed_payment_base_key.write(writer)?;
+		self.remote_tx_cache.remote_htlc_base_key.write(writer)?;
+		self.remote_csv.write(writer)?;
+
 		self.key_storage.write(writer)?;
 
 		writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
@@ -287,6 +301,16 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigne
 
 		let local_csv = Readable::read(reader)?;
 
+		let remote_tx_cache = {
+			let remote_delayed_payment_base_key = Readable::read(reader)?;
+			let remote_htlc_base_key = Readable::read(reader)?;
+			RemoteTxCache {
+				remote_delayed_payment_base_key,
+				remote_htlc_base_key,
+			}
+		};
+		let remote_csv = Readable::read(reader)?;
+
 		let key_storage = Readable::read(reader)?;
 
 		let pending_claim_requests_len: u64 = Readable::read(reader)?;
@@ -339,6 +363,8 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigne
 			prev_local_commitment,
 			prev_local_htlc_sigs,
 			local_csv,
+			remote_tx_cache,
+			remote_csv,
 			key_storage,
 			claimable_outpoints,
 			pending_claim_requests,
@@ -349,10 +375,15 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigne
 }
 
 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
-	pub(super) fn new(destination_script: Script, keys: ChanSigner, local_csv: u16) -> Self {
+	pub(super) fn new(destination_script: Script, keys: ChanSigner, local_csv: u16, remote_delayed_payment_base_key: PublicKey, remote_htlc_base_key: PublicKey, remote_csv: u16) -> Self {
 
 		let key_storage = keys;
 
+		let remote_tx_cache = RemoteTxCache {
+			remote_delayed_payment_base_key,
+			remote_htlc_base_key,
+		};
+
 		OnchainTxHandler {
 			destination_script,
 			local_commitment: None,
@@ -360,6 +391,8 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 			prev_local_commitment: None,
 			prev_local_htlc_sigs: None,
 			local_csv,
+			remote_tx_cache,
+			remote_csv,
 			key_storage,
 			pending_claim_requests: HashMap::new(),
 			claimable_outpoints: HashMap::new(),
-- 
2.30.2