//! [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
//! [messages]: crate::ln::msgs
+use {io, io_extras};
use prelude::*;
use core::{cmp, fmt};
+use core::hash::{Hash, Hasher};
use core::marker::PhantomData;
use bitcoin::bech32;
)*
];
}
+
+ impl alloc::fmt::Display for Features<$context> {
+ fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
+ $(
+ $(
+ fmt.write_fmt(format_args!("{}: {}, ", stringify!($required_feature),
+ if <$context as $required_feature>::requires_feature(&self.flags) { "required" }
+ else if <$context as $required_feature>::supports_feature(&self.flags) { "supported" }
+ else { "not supported" }))?;
+ )*
+ $(
+ fmt.write_fmt(format_args!("{}: {}, ", stringify!($optional_feature),
+ if <$context as $optional_feature>::requires_feature(&self.flags) { "required" }
+ else if <$context as $optional_feature>::supports_feature(&self.flags) { "supported" }
+ else { "not supported" }))?;
+ )*
+ )*
+ fmt.write_fmt(format_args!("unknown flags: {}",
+ if self.requires_unknown_bits() { "required" }
+ else if self.supports_unknown_bits() { "supported" } else { "none" }))
+ }
+ }
};
}
,
// Byte 3
,
+ // Byte 4
+ ,
+ // Byte 5
+ ,
+ // Byte 6
+ ,
],
optional_features: [
// Byte 0
BasicMPP,
// Byte 3
ShutdownAnySegwit,
+ // Byte 4
+ ,
+ // Byte 5
+ ,
+ // Byte 6
+ Keysend,
],
});
define_context!(ChannelContext {
BasicMPP,
],
});
+ // This isn't a "real" feature context, and is only used in the channel_type field in an
+ // `OpenChannel` message.
+ define_context!(ChannelTypeContext {
+ required_features: [
+ // Byte 0
+ ,
+ // Byte 1
+ StaticRemoteKey,
+ // Byte 2
+ ,
+ // Byte 3
+ ,
+ ],
+ optional_features: [
+ // Byte 0
+ ,
+ // Byte 1
+ ,
+ // Byte 2
+ ,
+ // Byte 3
+ ,
+ ],
+ });
/// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
/// useful for manipulating feature flags.
define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext],
"Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
set_variable_length_onion_required);
- define_feature!(13, StaticRemoteKey, [InitContext, NodeContext],
+ define_feature!(13, StaticRemoteKey, [InitContext, NodeContext, ChannelTypeContext],
"Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
set_static_remote_key_required);
define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
"Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
set_shutdown_any_segwit_required);
+ define_feature!(55, Keysend, [NodeContext],
+ "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required);
#[cfg(test)]
define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
}
}
}
+impl<T: sealed::Context> Hash for Features<T> {
+ fn hash<H: Hasher>(&self, hasher: &mut H) {
+ self.flags.hash(hasher);
+ }
+}
impl<T: sealed::Context> PartialEq for Features<T> {
fn eq(&self, o: &Self) -> bool {
self.flags.eq(&o.flags)
/// Features used within an invoice.
pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
+/// Features used within the channel_type field in an OpenChannel message.
+///
+/// A channel is always of some known "type", describing the transaction formats used and the exact
+/// semantics of our interaction with our peer.
+///
+/// Note that because a channel is a specific type which is proposed by the opener and accepted by
+/// the counterparty, only required features are allowed here.
+///
+/// This is serialized differently from other feature types - it is not prefixed by a length, and
+/// thus must only appear inside a TLV where its length is known in advance.
+pub type ChannelTypeFeatures = Features<sealed::ChannelTypeContext>;
+
impl InitFeatures {
/// Writes all features present up to, and including, 13.
- pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
+ pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
let len = cmp::min(2, self.flags.len());
- w.size_hint(len + 2);
(len as u16).write(w)?;
for i in (0..len).rev() {
if i == 0 {
pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
self.to_context_internal()
}
+
+ /// Getting a route for a keysend payment to a private node requires providing the payee's
+ /// features (since they were not announced in a node announcement). However, keysend payments
+ /// don't have an invoice to pull the payee's features from, so this method is provided for use in
+ /// [`Payee::for_keysend`], thus omitting the need for payers to manually construct an
+ /// `InvoiceFeatures` for [`find_route`].
+ ///
+ /// [`Payee::for_keysend`]: crate::routing::router::Payee::for_keysend
+ /// [`find_route`]: crate::routing::router::find_route
+ pub(crate) fn for_keysend() -> InvoiceFeatures {
+ InvoiceFeatures::empty().set_variable_length_onion_optional()
+ }
+}
+
+impl ChannelTypeFeatures {
+ /// Constructs the implicit channel type based on the common supported types between us and our
+ /// counterparty
+ pub(crate) fn from_counterparty_init(counterparty_init: &InitFeatures) -> Self {
+ let mut ret = counterparty_init.to_context_internal();
+ // 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;
+ }
+ ret
+ }
+
+ /// Constructs a ChannelTypeFeatures with only static_remotekey set
+ pub(crate) fn only_static_remote_key() -> Self {
+ let mut ret = Self::empty();
+ <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
+ ret
+ }
}
impl ToBase32 for InvoiceFeatures {
&self.flags
}
- pub(crate) fn requires_unknown_bits(&self) -> bool {
+ fn write_be<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ for f in self.flags.iter().rev() { // Swap back to big-endian
+ f.write(w)?;
+ }
+ Ok(())
+ }
+
+ fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
+ flags.reverse(); // Swap to little-endian
+ Self {
+ flags,
+ mark: PhantomData,
+ }
+ }
+
+ pub(crate) fn supports_any_optional_bits(&self) -> bool {
+ self.flags.iter().any(|&byte| (byte & 0b10_10_10_10) != 0)
+ }
+
+ /// Returns true if this `Features` object contains unknown feature flags which are set as
+ /// "required".
+ pub fn requires_unknown_bits(&self) -> bool {
// Bitwise AND-ing with all even bits set except for known features will select required
// unknown features.
let byte_count = T::KNOWN_FEATURE_MASK.len();
(byte & unknown_features) != 0
})
}
-
- /// The number of bytes required to represent the feature flags present. This does not include
- /// the length bytes which are included in the serialized form.
- pub(crate) fn byte_count(&self) -> usize {
- self.flags.len()
- }
}
impl<T: sealed::DataLossProtect> Features<T> {
pub(crate) fn requires_data_loss_protect(&self) -> bool {
<T as sealed::DataLossProtect>::requires_feature(&self.flags)
}
+ #[cfg(test)]
pub(crate) fn supports_data_loss_protect(&self) -> bool {
<T as sealed::DataLossProtect>::supports_feature(&self.flags)
}
self
}
}
-
-impl<T: sealed::Context> Writeable for Features<T> {
- fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
- w.size_hint(self.flags.len() + 2);
- (self.flags.len() as u16).write(w)?;
- for f in self.flags.iter().rev() { // Swap back to big-endian
- f.write(w)?;
+macro_rules! impl_feature_len_prefixed_write {
+ ($features: ident) => {
+ impl Writeable for $features {
+ fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ (self.flags.len() as u16).write(w)?;
+ self.write_be(w)
+ }
+ }
+ impl Readable for $features {
+ fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ Ok(Self::from_be_bytes(Vec::<u8>::read(r)?))
+ }
}
- Ok(())
}
}
-
-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 {
- flags,
- mark: PhantomData,
- })
+impl_feature_len_prefixed_write!(InitFeatures);
+impl_feature_len_prefixed_write!(ChannelFeatures);
+impl_feature_len_prefixed_write!(NodeFeatures);
+impl_feature_len_prefixed_write!(InvoiceFeatures);
+
+// Because ChannelTypeFeatures only appears inside of TLVs, it doesn't have a length prefix when
+// serialized. Thus, we can't use `impl_feature_len_prefixed_write`, above, and have to write our
+// own serialization.
+impl Writeable for ChannelTypeFeatures {
+ fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ self.write_be(w)
+ }
+}
+impl Readable for ChannelTypeFeatures {
+ fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ let v = io_extras::read_to_end(r)?;
+ Ok(Self::from_be_bytes(v))
}
}
#[cfg(test)]
mod tests {
- use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
+ use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
#[test]
#[test]
fn convert_to_context_with_unknown_flags() {
// Ensure the `from` context has fewer known feature bytes than the `to` context.
- assert!(InvoiceFeatures::known().byte_count() < NodeFeatures::known().byte_count());
+ assert!(InvoiceFeatures::known().flags.len() < NodeFeatures::known().flags.len());
let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional();
assert!(invoice_features.supports_unknown_bits());
let node_features: NodeFeatures = invoice_features.to_context();
let features_deserialized = InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
assert_eq!(features, features_deserialized);
}
+
+ #[test]
+ fn test_channel_type_mapping() {
+ // If we map an InvoiceFeatures with StaticRemoteKey optional, it should map into a
+ // required-StaticRemoteKey ChannelTypeFeatures.
+ let init_features = InitFeatures::empty().set_static_remote_key_optional();
+ let converted_features = ChannelTypeFeatures::from_counterparty_init(&init_features);
+ assert_eq!(converted_features, ChannelTypeFeatures::only_static_remote_key());
+ assert!(!converted_features.supports_any_optional_bits());
+ assert!(converted_features.requires_static_remote_key());
+ }
}
projects / rust-lightning / blobdiff