Add holder commitment point to unfunded channel context

Author: alecchendev

lightning/src/ln/channel.rs

@@ -954,18 +954,17 @@ enum HolderCommitmentPoint {
 }
 
 impl HolderCommitmentPoint {
-	pub fn new<SP: Deref>(signer: &ChannelSignerType<SP>, secp_ctx: &Secp256k1<secp256k1::All>) -> Self
+	pub fn new<SP: Deref>(signer: &ChannelSignerType<SP>, secp_ctx: &Secp256k1<secp256k1::All>) -> Option<Self>
 		where SP::Target: SignerProvider
 	{
-		HolderCommitmentPoint::Available {
-			transaction_number: INITIAL_COMMITMENT_NUMBER,
-			// TODO(async_signing): remove this expect with the Uninitialized variant
-			current: signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER, secp_ctx)
-				.expect("Signer must be able to provide initial commitment point"),
-			// TODO(async_signing): remove this expect with the Uninitialized variant
-			next: signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - 1, secp_ctx)
-				.expect("Signer must be able to provide second commitment point"),
-		}
+		let current = signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER, secp_ctx).ok()?;
+		let next = signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - 1, secp_ctx).ok();
+		let point = if let Some(next) = next {
+			HolderCommitmentPoint::Available { transaction_number: INITIAL_COMMITMENT_NUMBER, current, next }
+		} else {
+			HolderCommitmentPoint::PendingNext { transaction_number: INITIAL_COMMITMENT_NUMBER, current }
+		};
+		Some(point)
 	}
 
 	pub fn is_available(&self) -> bool {
@@ -1163,6 +1162,8 @@ pub(super) struct UnfundedChannelContext {
 	/// This is so that we don't keep channels around that haven't progressed to a funded state
 	/// in a timely manner.
 	unfunded_channel_age_ticks: usize,
+	/// Tracks the commitment number and commitment point before the channel is funded.
+	holder_commitment_point: Option<HolderCommitmentPoint>,
 }
 
 impl UnfundedChannelContext {
@@ -1174,6 +1175,11 @@ impl UnfundedChannelContext {
 		self.unfunded_channel_age_ticks += 1;
 		self.unfunded_channel_age_ticks >= UNFUNDED_CHANNEL_AGE_LIMIT_TICKS
 	}
+
+	fn transaction_number(&self) -> u64 {
+		self.holder_commitment_point.as_ref().map(|point| point.transaction_number())
+			.unwrap_or(INITIAL_COMMITMENT_NUMBER)
+	}
 }
 
 /// Contains everything about the channel including state, and various flags.
@@ -1685,7 +1691,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 		let value_to_self_msat = our_funding_satoshis * 1000 + msg_push_msat;
 
 		let holder_signer = ChannelSignerType::Ecdsa(holder_signer);
-		let holder_commitment_point = HolderCommitmentPoint::new(&holder_signer, &secp_ctx);
+		// Unwrap here since it gets removed in the next commit
+		let holder_commitment_point = HolderCommitmentPoint::new(&holder_signer, &secp_ctx).unwrap();
 
 		// TODO(dual_funding): Checks for `funding_feerate_sat_per_1000_weight`?
 
@@ -1921,7 +1928,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 		let temporary_channel_id = temporary_channel_id.unwrap_or_else(|| ChannelId::temporary_from_entropy_source(entropy_source));
 
 		let holder_signer = ChannelSignerType::Ecdsa(holder_signer);
-		let holder_commitment_point = HolderCommitmentPoint::new(&holder_signer, &secp_ctx);
+		// Unwrap here since it gets removed in the next commit
+		let holder_commitment_point = HolderCommitmentPoint::new(&holder_signer, &secp_ctx).unwrap();
 
 		Ok(Self {
 			user_id,
@@ -7643,28 +7651,31 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 		let holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
 		let pubkeys = holder_signer.pubkeys().clone();
 
-		let chan = Self {
-			context: ChannelContext::new_for_outbound_channel(
-				fee_estimator,
-				entropy_source,
-				signer_provider,
-				counterparty_node_id,
-				their_features,
-				channel_value_satoshis,
-				push_msat,
-				user_id,
-				config,
-				current_chain_height,
-				outbound_scid_alias,
-				temporary_channel_id,
-				holder_selected_channel_reserve_satoshis,
-				channel_keys_id,
-				holder_signer,
-				pubkeys,
-				logger,
-			)?,
-			unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 }
+		let context = ChannelContext::new_for_outbound_channel(
+			fee_estimator,
+			entropy_source,
+			signer_provider,
+			counterparty_node_id,
+			their_features,
+			channel_value_satoshis,
+			push_msat,
+			user_id,
+			config,
+			current_chain_height,
+			outbound_scid_alias,
+			temporary_channel_id,
+			holder_selected_channel_reserve_satoshis,
+			channel_keys_id,
+			holder_signer,
+			pubkeys,
+			logger,
+		)?;
+		let unfunded_context = UnfundedChannelContext {
+			unfunded_channel_age_ticks: 0,
+			holder_commitment_point: HolderCommitmentPoint::new(&context.holder_signer, &context.secp_ctx),
 		};
+
+		let chan = Self { context, unfunded_context };
 		Ok(chan)
 	}
 
@@ -8020,29 +8031,31 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 			htlc_basepoint: HtlcBasepoint::from(msg.common_fields.htlc_basepoint)
 		};
 
-		let chan = Self {
-			context: ChannelContext::new_for_inbound_channel(
-				fee_estimator,
-				entropy_source,
-				signer_provider,
-				counterparty_node_id,
-				their_features,
-				user_id,
-				config,
-				current_chain_height,
-				&&logger,
-				is_0conf,
-				0,
-
-				counterparty_pubkeys,
-				channel_type,
-				holder_selected_channel_reserve_satoshis,
-				msg.channel_reserve_satoshis,
-				msg.push_msat,
-				msg.common_fields.clone(),
-			)?,
-			unfunded_context: UnfundedChannelContext { unfunded_channel_age_ticks: 0 }
+		let context = ChannelContext::new_for_inbound_channel(
+			fee_estimator,
+			entropy_source,
+			signer_provider,
+			counterparty_node_id,
+			their_features,
+			user_id,
+			config,
+			current_chain_height,
+			&&logger,
+			is_0conf,
+			0,
+			counterparty_pubkeys,
+			channel_type,
+			holder_selected_channel_reserve_satoshis,
+			msg.channel_reserve_satoshis,
+			msg.push_msat,
+			msg.common_fields.clone(),
+		)?;
+		let unfunded_context = UnfundedChannelContext {
+			unfunded_channel_age_ticks: 0,
+			holder_commitment_point: HolderCommitmentPoint::new(&context.holder_signer, &context.secp_ctx),
 		};
+
+		let chan = Self { context, unfunded_context };
 		Ok(chan)
 	}