X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=47db8797b921bea535b2cad58bd819d9bc5f9bc1;hb=658b681772cbffdfbf8331caa1517ed20d1f5343;hp=c334074871eb486a924da2eabdde30865dc55e22;hpb=09d2a71352f738de1f4f36248a735e6383ee0d8d;p=rust-lightning

diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs
index c3340748..47db8797 100644
--- a/lightning/src/ln/features.rs
+++ b/lightning/src/ln/features.rs
@@ -29,6 +29,10 @@ mod sealed { // You should just use the type aliases instead.
 	pub trait UpfrontShutdownScript: Context {}
 	impl UpfrontShutdownScript for InitContext {}
 	impl UpfrontShutdownScript for NodeContext {}
+
+	pub trait VariableLengthOnion: Context {}
+	impl VariableLengthOnion for InitContext {}
+	impl VariableLengthOnion for NodeContext {}
 }
 
 /// Tracks the set of features which a node implements, templated by the context in which it
@@ -69,7 +73,7 @@ impl InitFeatures {
 	/// Create a Features with the features we support
 	pub fn supported() -> InitFeatures {
 		InitFeatures {
-			flags: vec![2 | 1 << 5],
+			flags: vec![2 | 1 << 5, 1 << (9-8)],
 			mark: PhantomData,
 		}
 	}
@@ -118,6 +122,13 @@ impl ChannelFeatures {
 			mark: PhantomData,
 		}
 	}
+
+	/// Takes the flags that we know how to interpret in an init-context features that are also
+	/// relevant in a channel-context features and creates a channel-context features from them.
+	pub(crate) fn with_known_relevant_init_flags(_init_ctx: &InitFeatures) -> Self {
+		// There are currently no channel flags defined that we understand.
+		Self { flags: Vec::new(), mark: PhantomData, }
+	}
 }
 
 impl NodeFeatures {
@@ -125,17 +136,34 @@ impl NodeFeatures {
 	#[cfg(not(feature = "fuzztarget"))]
 	pub(crate) fn supported() -> NodeFeatures {
 		NodeFeatures {
-			flags: vec![2 | 1 << 5],
+			flags: vec![2 | 1 << 5, 1 << (9-8)],
 			mark: PhantomData,
 		}
 	}
 	#[cfg(feature = "fuzztarget")]
 	pub fn supported() -> NodeFeatures {
 		NodeFeatures {
-			flags: vec![2 | 1 << 5],
+			flags: vec![2 | 1 << 5, 1 << (9-8)],
 			mark: PhantomData,
 		}
 	}
+
+	/// Takes the flags that we know how to interpret in an init-context features that are also
+	/// relevant in a node-context features and creates a node-context features from them.
+	pub(crate) fn with_known_relevant_init_flags(init_ctx: &InitFeatures) -> Self {
+		let mut flags = Vec::new();
+		for (i, feature_byte)in init_ctx.flags.iter().enumerate() {
+			match i {
+				// Blank out initial_routing_sync (feature bits 2/3), gossip_queries (6/7),
+				// gossip_queries_ex (10/11), option_static_remotekey (12/13), and
+				// payment_secret (14/15)
+				0 => flags.push(feature_byte & 0b00110011),
+				1 => flags.push(feature_byte & 0b00000011),
+				_ => (),
+			}
+		}
+		Self { flags, mark: PhantomData, }
+	}
 }
 
 impl<T: sealed::Context> Features<T> {
@@ -164,13 +192,30 @@ impl<T: sealed::Context> Features<T> {
 
 	pub(crate) fn requires_unknown_bits(&self) -> bool {
 		self.flags.iter().enumerate().any(|(idx, &byte)| {
-			( idx != 0 && (byte & 0x55) != 0 ) || ( idx == 0 && (byte & 0x14) != 0 )
+			(match idx {
+				// Unknown bits are even bits which we don't understand, we list ones which we do
+				// here:
+				// unknown, upfront_shutdown_script, unknown (actually initial_routing_sync, but it
+				// is only valid as an optional feature), and data_loss_protect:
+				0 => (byte & 0b01000100),
+				// unknown, unknown, unknown, var_onion_optin:
+				1 => (byte & 0b01010100),
+				// fallback, all even bits set:
+				_ => (byte & 0b01010101),
+			}) != 0
 		})
 	}
 
 	pub(crate) fn supports_unknown_bits(&self) -> bool {
 		self.flags.iter().enumerate().any(|(idx, &byte)| {
-			( idx != 0 && byte != 0 ) || ( idx == 0 && (byte & 0xc4) != 0 )
+			(match idx {
+				// unknown, upfront_shutdown_script, initial_routing_sync (is only valid as an
+				// optional feature), and data_loss_protect:
+				0 => (byte & 0b11000100),
+				// unknown, unknown, unknown, var_onion_optin:
+				1 => (byte & 0b11111100),
+				_ => byte,
+			}) != 0
 		})
 	}
 
@@ -214,6 +259,12 @@ impl<T: sealed::UpfrontShutdownScript> Features<T> {
 	}
 }
 
+impl<T: sealed::VariableLengthOnion> Features<T> {
+	pub(crate) fn supports_variable_length_onion(&self) -> bool {
+		self.flags.len() > 1 && (self.flags[1] & 3) != 0
+	}
+}
+
 impl<T: sealed::InitialRoutingSync> Features<T> {
 	pub(crate) fn initial_routing_sync(&self) -> bool {
 		self.flags.len() > 0 && (self.flags[0] & (1 << 3)) != 0
@@ -238,8 +289,8 @@ impl<T: sealed::Context> Writeable for Features<T> {
 	}
 }
 
-impl<R: ::std::io::Read, T: sealed::Context> Readable<R> for Features<T> {
-	fn read(r: &mut R) -> Result<Self, DecodeError> {
+impl<T: sealed::Context> Readable for Features<T> {
+	fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
 		let mut flags: Vec<u8> = Readable::read(r)?;
 		flags.reverse(); // Swap to little-endian
 		Ok(Self {
@@ -248,3 +299,62 @@ impl<R: ::std::io::Read, T: sealed::Context> Readable<R> for Features<T> {
 		})
 	}
 }
+
+#[cfg(test)]
+mod tests {
+	use super::{ChannelFeatures, InitFeatures, NodeFeatures, Features};
+
+	#[test]
+	fn sanity_test_our_features() {
+		assert!(!ChannelFeatures::supported().requires_unknown_bits());
+		assert!(!ChannelFeatures::supported().supports_unknown_bits());
+		assert!(!InitFeatures::supported().requires_unknown_bits());
+		assert!(!InitFeatures::supported().supports_unknown_bits());
+		assert!(!NodeFeatures::supported().requires_unknown_bits());
+		assert!(!NodeFeatures::supported().supports_unknown_bits());
+
+		assert!(InitFeatures::supported().supports_upfront_shutdown_script());
+		assert!(NodeFeatures::supported().supports_upfront_shutdown_script());
+
+		assert!(InitFeatures::supported().supports_data_loss_protect());
+		assert!(NodeFeatures::supported().supports_data_loss_protect());
+
+		assert!(InitFeatures::supported().supports_variable_length_onion());
+		assert!(NodeFeatures::supported().supports_variable_length_onion());
+
+		let mut init_features = InitFeatures::supported();
+		init_features.set_initial_routing_sync();
+		assert!(!init_features.requires_unknown_bits());
+		assert!(!init_features.supports_unknown_bits());
+	}
+
+	#[test]
+	fn sanity_test_unkown_bits_testing() {
+		let mut features = ChannelFeatures::supported();
+		features.set_require_unknown_bits();
+		assert!(features.requires_unknown_bits());
+		features.clear_require_unknown_bits();
+		assert!(!features.requires_unknown_bits());
+	}
+
+	#[test]
+	fn test_node_with_known_relevant_init_flags() {
+		// Create an InitFeatures with initial_routing_sync supported.
+		let mut init_features = InitFeatures::supported();
+		init_features.set_initial_routing_sync();
+
+		// Attempt to pull out non-node-context feature flags from these InitFeatures.
+		let res = NodeFeatures::with_known_relevant_init_flags(&init_features);
+
+		{
+			// Check that the flags are as expected.
+			assert_eq!(res.flags[0], 0b00100010);
+			assert_eq!(res.flags[1], 0b00000010);
+			assert_eq!(res.flags.len(), 2);
+		}
+
+		// Check that the initial_routing_sync feature was correctly blanked out.
+		let new_features: InitFeatures = Features::from_le_bytes(res.flags);
+		assert!(!new_features.initial_routing_sync());
+	}
+}