Make ChannelMonitor always clonable

Rather than `ChannelMonitor` only being clonable when the signer is
clonable, we require all signers to be clonable and then make all
`ChannelMonitor`s clonable.

Author: TheBlueMatt

lightning/src/chain/channelmonitor.rs

@@ -1078,10 +1078,7 @@ pub struct ChannelMonitor<Signer: EcdsaChannelSigner> {
 	pub(crate) inner: Mutex<ChannelMonitorImpl<Signer>>,
 }
 
-impl<Signer: EcdsaChannelSigner> Clone for ChannelMonitor<Signer>
-where
-	Signer: Clone,
-{
+impl<Signer: EcdsaChannelSigner> Clone for ChannelMonitor<Signer> {
 	fn clone(&self) -> Self {
 		let inner = self.inner.lock().unwrap().clone();
 		ChannelMonitor::from_impl(inner)

lightning/src/events/bump_transaction/mod.rs

@@ -31,7 +31,7 @@ use crate::ln::chan_utils::{
 };
 use crate::ln::types::ChannelId;
 use crate::prelude::*;
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::BaseEcdsaChannelSigner;
 use crate::sign::{
 	ChannelDerivationParameters, HTLCDescriptor, SignerProvider, P2WPKH_WITNESS_WEIGHT,
 };

lightning/src/ln/async_signer_tests.rs

@@ -22,7 +22,7 @@ use crate::ln::channel_state::{ChannelDetails, ChannelShutdownState};
 use crate::ln::channelmanager::{PaymentId, RAACommitmentOrder, RecipientOnionFields};
 use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, MessageSendEvent};
 use crate::ln::{functional_test_utils::*, msgs};
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::BaseEcdsaChannelSigner;
 use crate::sign::SignerProvider;
 use crate::util::logger::Logger;
 use crate::util::test_channel_signer::SignerOp;

lightning/src/ln/channel.rs

@@ -72,7 +72,7 @@ use crate::ln::types::ChannelId;
 use crate::ln::LN_MAX_MSG_LEN;
 use crate::offers::static_invoice::StaticInvoice;
 use crate::routing::gossip::NodeId;
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::{BaseEcdsaChannelSigner, EcdsaChannelSigner};
 use crate::sign::tx_builder::{HTLCAmountDirection, NextCommitmentStats, SpecTxBuilder, TxBuilder};
 use crate::sign::{ChannelSigner, EntropySource, NodeSigner, Recipient, SignerProvider};
 use crate::types::features::{ChannelTypeFeatures, InitFeatures};

lightning/src/ln/htlc_reserve_unit_tests.rs

@@ -15,7 +15,7 @@ use crate::ln::msgs::{self, BaseMessageHandler, ChannelMessageHandler, MessageSe
 use crate::ln::onion_utils::{self, AttributionData};
 use crate::ln::outbound_payment::RecipientOnionFields;
 use crate::routing::router::PaymentParameters;
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::BaseEcdsaChannelSigner;
 use crate::sign::tx_builder::{SpecTxBuilder, TxBuilder};
 use crate::types::features::ChannelTypeFeatures;
 use crate::types::payment::PaymentPreimage;

lightning/src/ln/monitor_tests.rs

@@ -11,7 +11,7 @@
 
 //! Further functional tests which test blockchain reorganizations.
 
-use crate::sign::{ecdsa::EcdsaChannelSigner, OutputSpender, SignerProvider, SpendableOutputDescriptor};
+use crate::sign::{ecdsa::BaseEcdsaChannelSigner, OutputSpender, SignerProvider, SpendableOutputDescriptor};
 use crate::chain::Watch;
 use crate::chain::channelmonitor::{Balance, BalanceSource, ChannelMonitorUpdateStep, HolderCommitmentTransactionBalance, ANTI_REORG_DELAY, ARCHIVAL_DELAY_BLOCKS, COUNTERPARTY_CLAIMABLE_WITHIN_BLOCKS_PINNABLE, LATENCY_GRACE_PERIOD_BLOCKS};
 use crate::chain::transaction::OutPoint;

lightning/src/ln/update_fee_tests.rs

@@ -15,7 +15,7 @@ use crate::ln::msgs::{
 	self, BaseMessageHandler, ChannelMessageHandler, ErrorAction, MessageSendEvent,
 };
 use crate::ln::outbound_payment::RecipientOnionFields;
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::BaseEcdsaChannelSigner;
 use crate::types::features::ChannelTypeFeatures;
 use crate::util::config::UserConfig;
 use crate::util::errors::APIError;

lightning/src/sign/ecdsa.rs

@@ -34,7 +34,25 @@ use crate::sign::{ChannelSigner, HTLCDescriptor};
 ///
 /// [`ChannelManager::signer_unblocked`]: crate::ln::channelmanager::ChannelManager::signer_unblocked
 /// [`ChainMonitor::signer_unblocked`]: crate::chain::chainmonitor::ChainMonitor::signer_unblocked
-pub trait EcdsaChannelSigner: ChannelSigner {
+pub trait EcdsaChannelSigner: BaseEcdsaChannelSigner + Clone {}
+
+/// A trait to sign Lightning channel transactions as described in
+/// [BOLT 3](https://github.com/lightning/bolts/blob/master/03-transactions.md).
+///
+/// Signing services could be implemented on a hardware wallet and should implement signing
+/// policies in order to be secure. Please refer to the [VLS Policy
+/// Controls](https://gitlab.com/lightning-signer/validating-lightning-signer/-/blob/main/docs/policy-controls.md)
+/// for an example of such policies.
+///
+/// Like [`ChannelSigner`], many of the methods allow errors to be returned to support async
+/// signing. In such cases, the signing operation can be replayed by calling
+/// [`ChannelManager::signer_unblocked`] or [`ChainMonitor::signer_unblocked`] (see individual
+/// method documentation for which method should be called) once the result is ready, at which
+/// point the channel operation will resume.
+///
+/// [`ChannelManager::signer_unblocked`]: crate::ln::channelmanager::ChannelManager::signer_unblocked
+/// [`ChainMonitor::signer_unblocked`]: crate::chain::chainmonitor::ChainMonitor::signer_unblocked
+pub trait BaseEcdsaChannelSigner: ChannelSigner {
 	/// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
 	///
 	/// Policy checks should be implemented in this function, including checking the amount

lightning/src/sign/mod.rs

@@ -64,7 +64,7 @@ use crate::util::transaction_utils;
 
 use crate::crypto::chacha20::ChaCha20;
 use crate::prelude::*;
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::{BaseEcdsaChannelSigner, EcdsaChannelSigner};
 #[cfg(taproot)]
 use crate::sign::taproot::TaprootChannelSigner;
 use crate::util::atomic_counter::AtomicCounter;
@@ -1516,7 +1516,9 @@ impl ChannelSigner for InMemorySigner {
 const MISSING_PARAMS_ERR: &'static str =
 	"ChannelTransactionParameters must be populated before signing operations";
 
-impl EcdsaChannelSigner for InMemorySigner {
+impl EcdsaChannelSigner for InMemorySigner {}
+
+impl BaseEcdsaChannelSigner for InMemorySigner {
 	fn sign_counterparty_commitment(
 		&self, channel_parameters: &ChannelTransactionParameters,
 		commitment_tx: &CommitmentTransaction, _inbound_htlc_preimages: Vec<PaymentPreimage>,
@@ -2691,11 +2693,11 @@ impl EntropySource for RandomBytes {
 	}
 }
 
-// Ensure that EcdsaChannelSigner can have a vtable
-#[test]
+// Ensure that EcdsaChannelSigner can have a vtable - not required in bindings
+/*#[test]
 pub fn dyn_sign() {
 	let _signer: Box<dyn EcdsaChannelSigner>;
-}
+}*/
 
 #[cfg(ldk_bench)]
 pub mod benches {

lightning/src/util/dyn_signer.rs

@@ -11,7 +11,7 @@ use crate::ln::chan_utils::{
 use crate::ln::inbound_payment::ExpandedKey;
 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
 use crate::ln::script::ShutdownScript;
-use crate::sign::ecdsa::EcdsaChannelSigner;
+use crate::sign::ecdsa::{BaseEcdsaChannelSigner, EcdsaChannelSigner};
 #[cfg(taproot)]
 use crate::sign::taproot::TaprootChannelSigner;
 use crate::sign::InMemorySigner;
@@ -33,11 +33,11 @@ use types::payment::PaymentPreimage;
 
 #[cfg(not(taproot))]
 /// A super-trait for all the traits that a dyn signer backing implements
-pub trait DynSignerTrait: EcdsaChannelSigner + Send + Sync {}
+pub trait DynSignerTrait: BaseEcdsaChannelSigner + Send + Sync {}
 
 #[cfg(taproot)]
 /// A super-trait for all the traits that a dyn signer backing implements
-pub trait DynSignerTrait: EcdsaChannelSigner + TaprootChannelSigner + Send + Sync {}
+pub trait DynSignerTrait: BaseEcdsaChannelSigner + TaprootChannelSigner + Send + Sync {}
 
 /// Helper to allow DynSigner to clone itself
 pub trait InnerSign: DynSignerTrait {
@@ -127,7 +127,9 @@ impl Clone for DynSigner {
 	}
 }
 
-delegate!(DynSigner, EcdsaChannelSigner, inner,
+impl EcdsaChannelSigner for DynSigner {}
+
+delegate!(DynSigner, BaseEcdsaChannelSigner, inner,
 	fn sign_holder_commitment(, channel_parameters: &ChannelTransactionParameters,
 		commitment_tx: &HolderCommitmentTransaction,
 		secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>,