Remove the `ChannelMonitor` secp context

`ChannelMonitor` indirectly already has a context - the
`OnchainTxHandler` has one. This makes it trivial to remove the
existing one, so we do so for a free memory usage reduction.

diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index a26866497fcc1df9d405aac495414c02cdfd969d..509ebed6fbad3a6bc597838ec01b7dcb367c33f4 100644 (file)
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -848,8 +848,6 @@ pub(crate) struct ChannelMonitorImpl<Signer: WriteableEcdsaChannelSigner> {
 
        /// The node_id of our counterparty
        counterparty_node_id: Option<PublicKey>,
-
-       secp_ctx: Secp256k1<secp256k1::All>, //TODO: dedup this a bit...
 }
 
 /// Transaction outputs to watch for on-chain spends.
@@ -1091,7 +1089,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 
                let onchain_tx_handler =
                        OnchainTxHandler::new(destination_script.clone(), keys,
-                       channel_parameters.clone(), initial_holder_commitment_tx, secp_ctx.clone());
+                       channel_parameters.clone(), initial_holder_commitment_tx, secp_ctx);
 
                let mut outputs_to_watch = HashMap::new();
                outputs_to_watch.insert(funding_info.0.txid, vec![(funding_info.0.index as u32, funding_info.1.clone())]);
@@ -1147,8 +1145,6 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 
                        best_block,
                        counterparty_node_id: Some(counterparty_node_id),
-
-                       secp_ctx,
                })
        }
 
@@ -2463,9 +2459,9 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                if commitment_number >= self.get_min_seen_secret() {
                        let secret = self.get_secret(commitment_number).unwrap();
                        let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
-                       let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
-                       let revocation_pubkey = chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint);
-                       let delayed_key = chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.counterparty_commitment_params.counterparty_delayed_payment_base_key);
+                       let per_commitment_point = PublicKey::from_secret_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_key);
+                       let revocation_pubkey = chan_utils::derive_public_revocation_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint);
+                       let delayed_key = chan_utils::derive_public_key(&self.onchain_tx_handler.secp_ctx, &PublicKey::from_secret_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_key), &self.counterparty_commitment_params.counterparty_delayed_payment_base_key);
 
                        let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.counterparty_commitment_params.on_counterparty_tx_csv, &delayed_key);
                        let revokeable_p2wsh = revokeable_redeemscript.to_v0_p2wsh();
@@ -2578,8 +2574,8 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 
                if let Some(transaction) = tx {
                        let revocation_pubkey = chan_utils::derive_public_revocation_key(
-                               &self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint);
-                       let delayed_key = chan_utils::derive_public_key(&self.secp_ctx,
+                               &self.onchain_tx_handler.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint);
+                       let delayed_key = chan_utils::derive_public_key(&self.onchain_tx_handler.secp_ctx,
                                &per_commitment_point,
                                &self.counterparty_commitment_params.counterparty_delayed_payment_base_key);
                        let revokeable_p2wsh = chan_utils::get_revokeable_redeemscript(&revocation_pubkey,
@@ -2636,7 +2632,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                        Ok(key) => key,
                        Err(_) => return (Vec::new(), None)
                };
-               let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
+               let per_commitment_point = PublicKey::from_secret_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_key);
 
                let htlc_txid = tx.txid();
                let mut claimable_outpoints = vec![];
@@ -3882,9 +3878,6 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                        (13, spendable_txids_confirmed, vec_type),
                });
 
-               let mut secp_ctx = Secp256k1::new();
-               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
-
                Ok((best_block.block_hash(), ChannelMonitor::from_impl(ChannelMonitorImpl {
                        latest_update_id,
                        commitment_transaction_number_obscure_factor,
@@ -3936,8 +3929,6 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
 
                        best_block,
                        counterparty_node_id,
-
-                       secp_ctx,
                })))
        }
 }