From 6052a446dcc6727819021d3df1c644397b7e7b4b Mon Sep 17 00:00:00 2001
From: Wilmer Paulino <wilmer.paulino@gmail.com>
Date: Tue, 13 Jul 2021 15:20:46 -0700
Subject: [PATCH] lnwire+feature: add feature bit for script enforced lease
 support

---
 feature/default_sets.go |  4 ++++
 feature/deps.go         |  4 ++++
 feature/manager.go      |  8 ++++++++
 lnwire/features.go      | 20 ++++++++++++++++++++
 server.go               |  9 +++++----
 5 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/feature/default_sets.go b/feature/default_sets.go
index 5ee98792a..d345c90df 100644
--- a/feature/default_sets.go
+++ b/feature/default_sets.go
@@ -64,4 +64,8 @@ var defaultSetDesc = setDesc{
 		SetInit:    {}, // I
 		SetNodeAnn: {}, // N
 	},
+	lnwire.ScriptEnforcedLeaseOptional: {
+		SetInit:    {}, // I
+		SetNodeAnn: {}, // N
+	},
 }
diff --git a/feature/deps.go b/feature/deps.go
index d6f57cb90..92b0c03d5 100644
--- a/feature/deps.go
+++ b/feature/deps.go
@@ -65,6 +65,10 @@ var deps = depDesc{
 		lnwire.PaymentAddrOptional: {},
 	},
 	lnwire.ExplicitChannelTypeOptional: {},
+	lnwire.ScriptEnforcedLeaseOptional: {
+		lnwire.ExplicitChannelTypeOptional:  {},
+		lnwire.AnchorsZeroFeeHtlcTxOptional: {},
+	},
 }
 
 // ValidateDeps asserts that a feature vector sets all features and their
diff --git a/feature/manager.go b/feature/manager.go
index 989180715..50a54d625 100644
--- a/feature/manager.go
+++ b/feature/manager.go
@@ -23,6 +23,10 @@ type Config struct {
 
 	// NoWumbo unsets any bits signalling support for wumbo channels.
 	NoWumbo bool
+
+	// NoScriptEnforcementLease unsets any bits signaling support for script
+	// enforced leases.
+	NoScriptEnforcementLease bool
 }
 
 // Manager is responsible for generating feature vectors for different requested
@@ -92,6 +96,10 @@ func newManager(cfg Config, desc setDesc) (*Manager, error) {
 			raw.Unset(lnwire.WumboChannelsOptional)
 			raw.Unset(lnwire.WumboChannelsRequired)
 		}
+		if cfg.NoScriptEnforcementLease {
+			raw.Unset(lnwire.ScriptEnforcedLeaseOptional)
+			raw.Unset(lnwire.ScriptEnforcedLeaseRequired)
+		}
 
 		// Ensure that all of our feature sets properly set any
 		// dependent features.
diff --git a/lnwire/features.go b/lnwire/features.go
index 98202841f..16dc83949 100644
--- a/lnwire/features.go
+++ b/lnwire/features.go
@@ -159,6 +159,24 @@ const (
 	// TODO: Decide on actual feature bit value.
 	ExplicitChannelTypeOptional = 2021
 
+	// ScriptEnforcedLeaseOptional is an optional feature bit that signals
+	// that the node requires channels having zero-fee second-level HTLC
+	// transactions, which also imply anchor commitments, along with an
+	// additional CLTV constraint of a channel lease's expiration height
+	// applied to all outputs that pay directly to the channel initiator.
+	//
+	// TODO: Decide on actual feature bit value.
+	ScriptEnforcedLeaseRequired FeatureBit = 2022
+
+	// ScriptEnforcedLeaseOptional is a required feature bit that signals
+	// that the node requires channels having zero-fee second-level HTLC
+	// transactions, which also imply anchor commitments, along with an
+	// additional CLTV constraint of a channel lease's expiration height
+	// applied to all outputs that pay directly to the channel initiator.
+	//
+	// TODO: Decide on actual feature bit value.
+	ScriptEnforcedLeaseOptional FeatureBit = 2023
+
 	// maxAllowedSize is a maximum allowed size of feature vector.
 	//
 	// NOTE: Within the protocol, the maximum allowed message size is 65535
@@ -206,6 +224,8 @@ var Features = map[FeatureBit]string{
 	AMPOptional:                   "amp",
 	ExplicitChannelTypeOptional:   "explicit-commitment-type",
 	ExplicitChannelTypeRequired:   "explicit-commitment-type",
+	ScriptEnforcedLeaseRequired:   "script-enforced-lease",
+	ScriptEnforcedLeaseOptional:   "script-enforced-lease",
 }
 
 // RawFeatureVector represents a set of feature bits as defined in BOLT-09.  A
diff --git a/server.go b/server.go
index 356e056da..e2eb3039f 100644
--- a/server.go
+++ b/server.go
@@ -516,10 +516,11 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 	)
 
 	featureMgr, err := feature.NewManager(feature.Config{
-		NoTLVOnion:        cfg.ProtocolOptions.LegacyOnion(),
-		NoStaticRemoteKey: cfg.ProtocolOptions.NoStaticRemoteKey(),
-		NoAnchors:         cfg.ProtocolOptions.NoAnchorCommitments(),
-		NoWumbo:           !cfg.ProtocolOptions.Wumbo(),
+		NoTLVOnion:               cfg.ProtocolOptions.LegacyOnion(),
+		NoStaticRemoteKey:        cfg.ProtocolOptions.NoStaticRemoteKey(),
+		NoAnchors:                cfg.ProtocolOptions.NoAnchorCommitments(),
+		NoWumbo:                  !cfg.ProtocolOptions.Wumbo(),
+		NoScriptEnforcementLease: cfg.ProtocolOptions.NoScriptEnforcementLease(),
 	})
 	if err != nil {
 		return nil, err