//! [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
//! [messages]: crate::ln::msgs
-use io;
+use {io, io_extras};
use prelude::*;
use core::{cmp, fmt};
use core::hash::{Hash, Hasher};
,
// Byte 3
,
+ // Byte 4
+ ,
+ // Byte 5
+ ,
],
optional_features: [
// Byte 0
BasicMPP,
// Byte 3
ShutdownAnySegwit,
+ // Byte 4
+ ,
+ // Byte 5
+ ChannelType,
],
});
define_context!(NodeContext {
// Byte 4
,
// Byte 5
- ,
+ ChannelType,
// Byte 6
Keysend,
],
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.
macro_rules! define_feature {
($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
- $required_setter: ident) => {
+ $required_setter: ident, $supported_getter: ident) => {
#[doc = $doc]
///
/// See [BOLT #9] for details.
<T as $feature>::set_required_bit(&mut self.flags);
self
}
+
+ /// Checks if this feature is supported.
+ pub fn $supported_getter(&self) -> bool {
+ <T as $feature>::supports_feature(&self.flags)
+ }
}
$(
const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
}
)*
-
+ };
+ ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
+ $required_setter: ident, $supported_getter: ident, $required_getter: ident) => {
+ define_feature!($odd_bit, $feature, [$($context),+], $doc, $optional_setter, $required_setter, $supported_getter);
+ impl <T: $feature> Features<T> {
+ /// Checks if this feature is required.
+ pub fn $required_getter(&self) -> bool {
+ <T as $feature>::requires_feature(&self.flags)
+ }
+ }
}
}
define_feature!(1, DataLossProtect, [InitContext, NodeContext],
"Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
- set_data_loss_protect_required);
+ set_data_loss_protect_required, supports_data_loss_protect, requires_data_loss_protect);
// NOTE: Per Bolt #9, initial_routing_sync has no even bit.
define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
- set_initial_routing_sync_optional, set_initial_routing_sync_required);
+ set_initial_routing_sync_optional, set_initial_routing_sync_required,
+ initial_routing_sync);
define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
"Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
- set_upfront_shutdown_script_required);
+ set_upfront_shutdown_script_required, supports_upfront_shutdown_script,
+ requires_upfront_shutdown_script);
define_feature!(7, GossipQueries, [InitContext, NodeContext],
- "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required);
+ "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required,
+ supports_gossip_queries, requires_gossip_queries);
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],
+ set_variable_length_onion_required, supports_variable_length_onion,
+ requires_variable_length_onion);
+ define_feature!(13, StaticRemoteKey, [InitContext, NodeContext, ChannelTypeContext],
"Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
- set_static_remote_key_required);
+ set_static_remote_key_required, supports_static_remote_key, requires_static_remote_key);
define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
- "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required);
+ "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required,
+ supports_payment_secret, requires_payment_secret);
define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
- "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required);
+ "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
+ supports_basic_mpp, requires_basic_mpp);
define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
"Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
- set_shutdown_any_segwit_required);
+ set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
+ define_feature!(45, ChannelType, [InitContext, NodeContext],
+ "Feature flags for `option_channel_type`.", set_channel_type_optional,
+ set_channel_type_required, supports_channel_type, requires_channel_type);
define_feature!(55, Keysend, [NodeContext],
- "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required);
+ "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
+ supports_keysend, requires_keysend);
#[cfg(test)]
define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
"Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
- set_unknown_feature_required);
+ set_unknown_feature_required, supports_unknown_test_feature, requires_unknown_test_feature);
}
/// Tracks the set of features which a node implements, templated by the context in which it
/// 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<(), io::Error> {
/// 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
- /// [`get_keysend_route`], thus omitting the need for payers to manually construct an
- /// `InvoiceFeatures` for [`get_route`].
+ /// [`Payee::for_keysend`], thus omitting the need for payers to manually construct an
+ /// `InvoiceFeatures` for [`find_route`].
///
- /// [`get_keysend_route`]: crate::routing::router::get_keysend_route
- /// [`get_route`]: crate::routing::router::get_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 {
fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
// Explanation for the "4": the normal way to round up when dividing is to add the divisor
&self.flags
}
+ 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 {
}
}
-impl<T: sealed::DataLossProtect> Features<T> {
- #[cfg(test)]
- 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)
- }
-}
-
impl<T: sealed::UpfrontShutdownScript> Features<T> {
- #[cfg(test)]
- pub(crate) fn requires_upfront_shutdown_script(&self) -> bool {
- <T as sealed::UpfrontShutdownScript>::requires_feature(&self.flags)
- }
- pub(crate) fn supports_upfront_shutdown_script(&self) -> bool {
- <T as sealed::UpfrontShutdownScript>::supports_feature(&self.flags)
- }
#[cfg(test)]
pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
<T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
impl<T: sealed::GossipQueries> Features<T> {
- #[cfg(test)]
- pub(crate) fn requires_gossip_queries(&self) -> bool {
- <T as sealed::GossipQueries>::requires_feature(&self.flags)
- }
- pub(crate) fn supports_gossip_queries(&self) -> bool {
- <T as sealed::GossipQueries>::supports_feature(&self.flags)
- }
#[cfg(test)]
pub(crate) fn clear_gossip_queries(mut self) -> Self {
<T as sealed::GossipQueries>::clear_bits(&mut self.flags);
}
}
-impl<T: sealed::VariableLengthOnion> Features<T> {
- #[cfg(test)]
- pub(crate) fn requires_variable_length_onion(&self) -> bool {
- <T as sealed::VariableLengthOnion>::requires_feature(&self.flags)
- }
- pub(crate) fn supports_variable_length_onion(&self) -> bool {
- <T as sealed::VariableLengthOnion>::supports_feature(&self.flags)
- }
-}
-
-impl<T: sealed::StaticRemoteKey> Features<T> {
- pub(crate) fn supports_static_remote_key(&self) -> bool {
- <T as sealed::StaticRemoteKey>::supports_feature(&self.flags)
- }
- #[cfg(test)]
- pub(crate) fn requires_static_remote_key(&self) -> bool {
- <T as sealed::StaticRemoteKey>::requires_feature(&self.flags)
- }
-}
-
impl<T: sealed::InitialRoutingSync> Features<T> {
- pub(crate) fn initial_routing_sync(&self) -> bool {
- <T as sealed::InitialRoutingSync>::supports_feature(&self.flags)
- }
// We are no longer setting initial_routing_sync now that gossip_queries
// is enabled. This feature is ignored by a peer when gossip_queries has
// been negotiated.
}
}
-impl<T: sealed::PaymentSecret> Features<T> {
- #[cfg(test)]
- pub(crate) fn requires_payment_secret(&self) -> bool {
- <T as sealed::PaymentSecret>::requires_feature(&self.flags)
- }
- /// Returns whether the `payment_secret` feature is supported.
- pub fn supports_payment_secret(&self) -> bool {
- <T as sealed::PaymentSecret>::supports_feature(&self.flags)
- }
-}
-
-impl<T: sealed::BasicMPP> Features<T> {
- #[cfg(test)]
- pub(crate) fn requires_basic_mpp(&self) -> bool {
- <T as sealed::BasicMPP>::requires_feature(&self.flags)
- }
- // We currently never test for this since we don't actually *generate* multipath routes.
- pub(crate) fn supports_basic_mpp(&self) -> bool {
- <T as sealed::BasicMPP>::supports_feature(&self.flags)
- }
-}
-
impl<T: sealed::ShutdownAnySegwit> Features<T> {
- pub(crate) fn supports_shutdown_anysegwit(&self) -> bool {
- <T as sealed::ShutdownAnySegwit>::supports_feature(&self.flags)
- }
#[cfg(test)]
pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
<T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
self
}
}
-
-impl<T: sealed::Context> Writeable for Features<T> {
- fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
- (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> {
+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 mut flags: Vec<u8> = Readable::read(r)?;
- flags.reverse(); // Swap to little-endian
- Ok(Self {
- flags,
- mark: PhantomData,
- })
+ 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]
assert!(!NodeFeatures::known().requires_basic_mpp());
assert!(!InvoiceFeatures::known().requires_basic_mpp());
+ assert!(InitFeatures::known().supports_channel_type());
+ assert!(NodeFeatures::known().supports_channel_type());
+ assert!(!InitFeatures::known().requires_channel_type());
+ assert!(!NodeFeatures::known().requires_channel_type());
+
assert!(InitFeatures::known().supports_shutdown_anysegwit());
assert!(NodeFeatures::known().supports_shutdown_anysegwit());
// - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
// - basic_mpp
// - opt_shutdown_anysegwit
- assert_eq!(node_features.flags.len(), 4);
+ // -
+ // - option_channel_type
+ assert_eq!(node_features.flags.len(), 6);
assert_eq!(node_features.flags[0], 0b00000010);
assert_eq!(node_features.flags[1], 0b01010001);
assert_eq!(node_features.flags[2], 0b00000010);
assert_eq!(node_features.flags[3], 0b00001000);
+ assert_eq!(node_features.flags[4], 0b00000000);
+ assert_eq!(node_features.flags[5], 0b00100000);
}
// Check that cleared flags are kept blank when converting back:
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());
+ }
}