X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=51c608c1a6b47231762bbb35627032dcf33d19bc;hb=refs%2Fheads%2Fupstream%2Fmain;hp=9dcac57888a4dc6416660cb41eef35669dcae8e3;hpb=158ef6ffe3d347c1ea736d7ee1e1f8034b20725b;p=rust-lightning

diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs
index 9dcac578..51c608c1 100644
--- a/lightning/src/ln/features.rs
+++ b/lightning/src/ln/features.rs
@@ -87,8 +87,7 @@ use core::borrow::Borrow;
 use core::hash::{Hash, Hasher};
 use core::marker::PhantomData;
 
-use bitcoin::bech32;
-use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
+use bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
 use crate::ln::msgs::DecodeError;
 use crate::util::ser::{Readable, WithoutLength, Writeable, Writer};
 
@@ -443,6 +442,9 @@ mod sealed {
 		set_unknown_feature_required, supports_unknown_test_feature, requires_unknown_test_feature);
 }
 
+const ANY_REQUIRED_FEATURES_MASK: u8 = 0b01_01_01_01;
+const ANY_OPTIONAL_FEATURES_MASK: u8 = 0b10_10_10_10;
+
 /// Tracks the set of features which a node implements, templated by the context in which it
 /// appears.
 ///
@@ -616,8 +618,8 @@ impl ChannelTypeFeatures {
 		// ChannelTypeFeatures must only contain required bits, so we OR the required forms of all
 		// optional bits and then AND out the optional ones.
 		for byte in ret.flags.iter_mut() {
-			*byte |= (*byte & 0b10_10_10_10) >> 1;
-			*byte &= 0b01_01_01_01;
+			*byte |= (*byte & ANY_OPTIONAL_FEATURES_MASK) >> 1;
+			*byte &= ANY_REQUIRED_FEATURES_MASK;
 		}
 		ret
 	}
@@ -762,7 +764,7 @@ impl<T: sealed::Context> Features<T> {
 	}
 
 	pub(crate) fn supports_any_optional_bits(&self) -> bool {
-		self.flags.iter().any(|&byte| (byte & 0b10_10_10_10) != 0)
+		self.flags.iter().any(|&byte| (byte & ANY_OPTIONAL_FEATURES_MASK) != 0)
 	}
 
 	/// Returns true if this `Features` object contains required features unknown by `other`.
@@ -770,17 +772,8 @@ impl<T: sealed::Context> Features<T> {
 		// Bitwise AND-ing with all even bits set except for known features will select required
 		// unknown features.
 		self.flags.iter().enumerate().any(|(i, &byte)| {
-			const REQUIRED_FEATURES: u8 = 0b01_01_01_01;
-			const OPTIONAL_FEATURES: u8 = 0b10_10_10_10;
-			let unknown_features = if i < other.flags.len() {
-				// Form a mask similar to !T::KNOWN_FEATURE_MASK only for `other`
-				!(other.flags[i]
-					| ((other.flags[i] >> 1) & REQUIRED_FEATURES)
-					| ((other.flags[i] << 1) & OPTIONAL_FEATURES))
-			} else {
-				0b11_11_11_11
-			};
-			(byte & (REQUIRED_FEATURES & unknown_features)) != 0
+			let unknown_features = unset_features_mask_at_position(other, i);
+			(byte & (ANY_REQUIRED_FEATURES_MASK & unknown_features)) != 0
 		})
 	}
 
@@ -790,17 +783,7 @@ impl<T: sealed::Context> Features<T> {
 		// Bitwise AND-ing with all even bits set except for known features will select required
 		// unknown features.
 		self.flags.iter().enumerate().for_each(|(i, &byte)| {
-			const REQUIRED_FEATURES: u8 = 0b01_01_01_01;
-			const OPTIONAL_FEATURES: u8 = 0b10_10_10_10;
-			let unknown_features = if i < other.flags.len() {
-				// Form a mask similar to !T::KNOWN_FEATURE_MASK only for `other`
-				!(other.flags[i]
-					| ((other.flags[i] >> 1) & REQUIRED_FEATURES)
-					| ((other.flags[i] << 1) & OPTIONAL_FEATURES))
-			} else {
-				0b11_11_11_11
-			};
-
+			let unknown_features = unset_features_mask_at_position(other, i);
 			if byte & unknown_features != 0 {
 				for bit in (0..8).step_by(2) {
 					if ((byte & unknown_features) >> bit) & 1 == 1 {
@@ -820,13 +803,12 @@ impl<T: sealed::Context> Features<T> {
 		// unknown features.
 		let byte_count = T::KNOWN_FEATURE_MASK.len();
 		self.flags.iter().enumerate().any(|(i, &byte)| {
-			let required_features = 0b01_01_01_01;
 			let unknown_features = if i < byte_count {
 				!T::KNOWN_FEATURE_MASK[i]
 			} else {
 				0b11_11_11_11
 			};
-			(byte & (required_features & unknown_features)) != 0
+			(byte & (ANY_REQUIRED_FEATURES_MASK & unknown_features)) != 0
 		})
 	}
 
@@ -1047,10 +1029,21 @@ impl<T: sealed::Context> Readable for WithoutLength<Features<T>> {
 	}
 }
 
+pub(crate) fn unset_features_mask_at_position<T: sealed::Context>(other: &Features<T>, index: usize) -> u8 {
+	if index < other.flags.len() {
+		// Form a mask similar to !T::KNOWN_FEATURE_MASK only for `other`
+		!(other.flags[index]
+			| ((other.flags[index] >> 1) & ANY_REQUIRED_FEATURES_MASK)
+			| ((other.flags[index] << 1) & ANY_OPTIONAL_FEATURES_MASK))
+	} else {
+		0b11_11_11_11
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, Bolt11InvoiceFeatures, NodeFeatures, OfferFeatures, sealed};
-	use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
+	use bech32::{Base32Len, FromBase32, ToBase32, u5};
 	use crate::util::ser::{Readable, WithoutLength, Writeable};
 
 	#[test]