X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=ca6ea70b61da7312de22b1e28749a51cb3f28941;hb=cfc7ec66f03a0eb9489af2c433597d9123d07ca3;hp=b769fda07f9bbd8d812b8dbd49b87fd28bd31e66;hpb=7d406d95b4318103b199ff244923e2bc39f70c55;p=rust-lightning

diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs
index b769fda0..ca6ea70b 100644
--- a/lightning/src/ln/features.rs
+++ b/lightning/src/ln/features.rs
@@ -65,12 +65,19 @@
 //!     [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
 //!     information).
 //!
+//! LDK knows about the following features, but does not support them:
+//! - `AnchorsNonzeroFeeHtlcTx` - the initial version of anchor outputs, which was later found to be
+//!     vulnerable (see this
+//!     [mailing list post](https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-September/002796.html)
+//!     for more information).
+//!
 //! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
 //! [messages]: crate::ln::msgs
 
 use crate::{io, io_extras};
 use crate::prelude::*;
 use core::{cmp, fmt};
+use core::borrow::Borrow;
 use core::hash::{Hash, Hasher};
 use core::marker::PhantomData;
 
@@ -425,15 +432,21 @@ pub struct Features<T: sealed::Context> {
 	mark: PhantomData<T>,
 }
 
+impl<T: sealed::Context, Rhs: Borrow<Self>> core::ops::BitOrAssign<Rhs> for Features<T> {
+	fn bitor_assign(&mut self, rhs: Rhs) {
+		let total_feature_len = cmp::max(self.flags.len(), rhs.borrow().flags.len());
+		self.flags.resize(total_feature_len, 0u8);
+		for (byte, rhs_byte) in self.flags.iter_mut().zip(rhs.borrow().flags.iter()) {
+			*byte |= *rhs_byte;
+		}
+	}
+}
+
 impl<T: sealed::Context> core::ops::BitOr for Features<T> {
 	type Output = Self;
 
 	fn bitor(mut self, o: Self) -> Self {
-		let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
-		self.flags.resize(total_feature_len, 0u8);
-		for (byte, o_byte) in self.flags.iter_mut().zip(o.flags.iter()) {
-			*byte |= *o_byte;
-		}
+		self |= o;
 		self
 	}
 }
@@ -581,6 +594,14 @@ impl ChannelTypeFeatures {
 		<sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
 		ret
 	}
+
+	/// Constructs a ChannelTypeFeatures with anchors support
+	pub(crate) fn anchors_zero_htlc_fee_and_dependencies() -> Self {
+		let mut ret = Self::empty();
+		<sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
+		<sealed::ChannelTypeContext as sealed::AnchorsZeroFeeHtlcTx>::set_required_bit(&mut ret.flags);
+		ret
+	}
 }
 
 impl ToBase32 for InvoiceFeatures {