X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=d10c3a71927b254854fd11869f1d9cbaedf7cb35;hb=fba99b73bf5d23cb0ca554997dcb92dbaddd9cfc;hp=5de383b1f4469273207441892a90d1d2c063494d;hpb=d7e3320c030654ca3ff2b6ffd83ae65dfbe5e3c8;p=rust-lightning

diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs
index 5de383b1..d10c3a71 100644
--- a/lightning/src/ln/features.rs
+++ b/lightning/src/ln/features.rs
@@ -143,7 +143,7 @@ mod sealed {
 		// Byte 2
 		BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
 		// Byte 3
-		ShutdownAnySegwit,
+		ShutdownAnySegwit | Taproot,
 		// Byte 4
 		OnionMessages,
 		// Byte 5
@@ -159,7 +159,7 @@ mod sealed {
 		// Byte 2
 		BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
 		// Byte 3
-		ShutdownAnySegwit,
+		ShutdownAnySegwit | Taproot,
 		// Byte 4
 		OnionMessages,
 		// Byte 5
@@ -205,7 +205,7 @@ mod sealed {
 		// Byte 2
 		AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
 		// Byte 3
-		,
+		Taproot,
 		// Byte 4
 		,
 		// Byte 5
@@ -394,6 +394,9 @@ mod sealed {
 	define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
 		"Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
 		set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
+	define_feature!(31, Taproot, [InitContext, NodeContext, ChannelTypeContext],
+		"Feature flags for `option_taproot`.", set_taproot_optional,
+		set_taproot_required, supports_taproot, requires_taproot);
 	define_feature!(39, OnionMessages, [InitContext, NodeContext],
 		"Feature flags for `option_onion_messages`.", set_onion_messages_optional,
 		set_onion_messages_required, supports_onion_messages, requires_onion_messages);
@@ -715,7 +718,11 @@ impl<T: sealed::Context> Features<T> {
 		Ok(())
 	}
 
-	fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
+	/// Create a [`Features`] given a set of flags, in big-endian. This is in byte order from
+	/// most on-the-wire encodings.
+	///
+	/// This is not exported to bindings users as we don't support export across multiple T
+	pub fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
 		flags.reverse(); // Swap to little-endian
 		Self {
 			flags,
@@ -795,6 +802,35 @@ impl<T: sealed::Context> Features<T> {
 		true
 	}
 
+	/// Sets a required feature bit. Errors if `bit` is outside the feature range as defined
+	/// by [BOLT 9].
+	///
+	/// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
+	/// be set instead (i.e., `bit - 1`).
+	///
+	/// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
+	pub fn set_required_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+		self.set_feature_bit(bit - (bit % 2))
+	}
+
+	/// Sets an optional feature bit. Errors if `bit` is outside the feature range as defined
+	/// by [BOLT 9].
+	///
+	/// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
+	/// set instead (i.e., `bit + 1`).
+	///
+	/// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
+	pub fn set_optional_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+		self.set_feature_bit(bit + (1 - (bit % 2)))
+	}
+
+	fn set_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+		if bit > 255 {
+			return Err(());
+		}
+		self.set_bit(bit, false)
+	}
+
 	/// Sets a required custom feature bit. Errors if `bit` is outside the custom range as defined
 	/// by [bLIP 2] or if it is a known `T` feature.
 	///
@@ -821,10 +857,13 @@ impl<T: sealed::Context> Features<T> {
 		if bit < 256 {
 			return Err(());
 		}
+		self.set_bit(bit, true)
+	}
 
+	fn set_bit(&mut self, bit: usize, custom: bool) -> Result<(), ()> {
 		let byte_offset = bit / 8;
 		let mask = 1 << (bit - 8 * byte_offset);
-		if byte_offset < T::KNOWN_FEATURE_MASK.len() {
+		if byte_offset < T::KNOWN_FEATURE_MASK.len() && custom {
 			if (T::KNOWN_FEATURE_MASK[byte_offset] & mask) != 0 {
 				return Err(());
 			}
@@ -1075,6 +1114,13 @@ mod tests {
 		assert!(!features.requires_basic_mpp());
 		assert!(features.requires_payment_secret());
 		assert!(features.supports_payment_secret());
+
+		// Set flags manually
+		let mut features = NodeFeatures::empty();
+		assert!(features.set_optional_feature_bit(55).is_ok());
+		assert!(features.supports_keysend());
+		assert!(features.set_optional_feature_bit(255).is_ok());
+		assert!(features.set_required_feature_bit(256).is_err());
 	}
 
 	#[test]