--- /dev/null
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! Feature flag definitions for the Lightning protocol according to [BOLT #9].
+//!
+//! Lightning nodes advertise a supported set of operation through feature flags. Features are
+//! applicable for a specific context. [`Features`] encapsulates behavior for specifying and
+//! checking feature flags for a particular context. Each feature is defined internally by a trait
+//! specifying the corresponding flags (i.e., even and odd bits).
+//!
+//! Whether a feature is considered "known" or "unknown" is relative to the implementation, whereas
+//! the term "supports" is used in reference to a particular set of [`Features`]. That is, a node
+//! supports a feature if it advertises the feature (as either required or optional) to its peers.
+//! And the implementation can interpret a feature if the feature is known to it.
+//!
+//! The following features are currently required in the LDK:
+//! - `VariableLengthOnion` - requires/supports variable-length routing onion payloads
+//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md) for more information).
+//! - `StaticRemoteKey` - requires/supports static key for remote output
+//! (see [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more information).
+//!
+//! The following features are currently supported in the LDK:
+//! - `DataLossProtect` - requires/supports that a node which has somehow fallen behind, e.g., has been restored from an old backup,
+//! can detect that it has fallen behind
+//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
+//! - `InitialRoutingSync` - requires/supports that the sending node needs a complete routing information dump
+//! (see [BOLT-7](https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#initial-sync) for more information).
+//! - `UpfrontShutdownScript` - commits to a shutdown scriptpubkey when opening a channel
+//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
+//! - `GossipQueries` - requires/supports more sophisticated gossip control
+//! (see [BOLT-7](https://github.com/lightning/bolts/blob/master/07-routing-gossip.md) for more information).
+//! - `PaymentSecret` - requires/supports that a node supports payment_secret field
+//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md) for more information).
+//! - `BasicMPP` - requires/supports that a node can receive basic multi-part payments
+//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#basic-multi-part-payments) for more information).
+//! - `Wumbo` - requires/supports that a node create large channels. Called `option_support_large_channel` in the spec.
+//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
+//! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
+//! and HTLC transactions are pre-signed with zero fee (see
+//! [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
+//! information).
+//! - `RouteBlinding` - requires/supports that a node can relay payments over blinded paths
+//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#route-blinding) for more information).
+//! - `ShutdownAnySegwit` - requires/supports that future segwit versions are allowed in `shutdown`
+//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
+//! - `OnionMessages` - requires/supports forwarding onion messages
+//! (see [BOLT-7](https://github.com/lightning/bolts/pull/759/files) for more information).
+// TODO: update link
+//! - `ChannelType` - node supports the channel_type field in open/accept
+//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
+//! - `SCIDPrivacy` - supply channel aliases for routing
+//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
+//! - `PaymentMetadata` - include additional data in invoices which is passed to recipients in the
+//! onion.
+//! (see [BOLT-11](https://github.com/lightning/bolts/blob/master/11-payment-encoding.md) for
+//! more).
+//! - `ZeroConf` - supports accepting HTLCs and using channels prior to funding confirmation
+//! (see
+//! [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-channel_ready-message)
+//! for more info).
+//! - `Keysend` - send funds to a node without an invoice
+//! (see the [`Keysend` feature assignment proposal](https://github.com/lightning/bolts/issues/605#issuecomment-606679798) for more information).
+//! - `Trampoline` - supports receiving and forwarding Trampoline payments
+//! (see the [`Trampoline` feature proposal](https://github.com/lightning/bolts/pull/836) 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
+
+use core::{cmp, fmt};
+use core::borrow::Borrow;
+use core::hash::{Hash, Hasher};
+use core::marker::PhantomData;
+
+use alloc::vec::Vec;
+use alloc::vec;
+
+use bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
+
+mod sealed {
+ use super::*;
+
+ /// The context in which [`Features`] are applicable. Defines which features are known to the
+ /// implementation, though specification of them as required or optional is up to the code
+ /// constructing a features object.
+ pub trait Context {
+ /// Bitmask for selecting features that are known to the implementation.
+ const KNOWN_FEATURE_MASK: &'static [u8];
+ }
+
+ /// Defines a [`Context`] by stating which features it requires and which are optional. Features
+ /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
+ /// feature identifiers.
+ macro_rules! define_context {
+ ($context: ident, [$( $( $known_feature: ident )|*, )*]) => {
+ #[derive(Eq, PartialEq)]
+ pub struct $context {}
+
+ impl Context for $context {
+ const KNOWN_FEATURE_MASK: &'static [u8] = &[
+ $(
+ 0b00_00_00_00 $(|
+ <Self as $known_feature>::REQUIRED_MASK |
+ <Self as $known_feature>::OPTIONAL_MASK)*,
+ )*
+ ];
+ }
+
+ impl alloc::fmt::Display for Features<$context> {
+ fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
+ $(
+ $(
+ fmt.write_fmt(format_args!("{}: {}, ", stringify!($known_feature),
+ if <$context as $known_feature>::requires_feature(&self.flags) { "required" }
+ else if <$context as $known_feature>::supports_feature(&self.flags) { "supported" }
+ else { "not supported" }))?;
+ )*
+ {} // Rust gets mad if we only have a $()* block here, so add a dummy {}
+ )*
+ fmt.write_fmt(format_args!("unknown flags: {}",
+ if self.requires_unknown_bits() { "required" }
+ else if self.supports_unknown_bits() { "supported" } else { "none" }))
+ }
+ }
+ };
+ }
+
+ define_context!(InitContext, [
+ // Byte 0
+ DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
+ // Byte 1
+ VariableLengthOnion | StaticRemoteKey | PaymentSecret,
+ // Byte 2
+ BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
+ // Byte 3
+ RouteBlinding | ShutdownAnySegwit | Taproot,
+ // Byte 4
+ OnionMessages,
+ // Byte 5
+ ChannelType | SCIDPrivacy,
+ // Byte 6
+ ZeroConf,
+ // Byte 7
+ Trampoline,
+ ]);
+ define_context!(NodeContext, [
+ // Byte 0
+ DataLossProtect | UpfrontShutdownScript | GossipQueries,
+ // Byte 1
+ VariableLengthOnion | StaticRemoteKey | PaymentSecret,
+ // Byte 2
+ BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
+ // Byte 3
+ RouteBlinding | ShutdownAnySegwit | Taproot,
+ // Byte 4
+ OnionMessages,
+ // Byte 5
+ ChannelType | SCIDPrivacy,
+ // Byte 6
+ ZeroConf | Keysend,
+ // Byte 7
+ Trampoline,
+ ]);
+ define_context!(ChannelContext, []);
+ define_context!(Bolt11InvoiceContext, [
+ // Byte 0
+ ,
+ // Byte 1
+ VariableLengthOnion | PaymentSecret,
+ // Byte 2
+ BasicMPP,
+ // Byte 3
+ ,
+ // Byte 4
+ ,
+ // Byte 5
+ ,
+ // Byte 6
+ PaymentMetadata,
+ // Byte 7
+ Trampoline,
+ ]);
+ define_context!(OfferContext, []);
+ define_context!(InvoiceRequestContext, []);
+ define_context!(Bolt12InvoiceContext, [
+ // Byte 0
+ ,
+ // Byte 1
+ ,
+ // Byte 2
+ BasicMPP,
+ ]);
+ define_context!(BlindedHopContext, []);
+ // This isn't a "real" feature context, and is only used in the channel_type field in an
+ // `OpenChannel` message.
+ define_context!(ChannelTypeContext, [
+ // Byte 0
+ ,
+ // Byte 1
+ StaticRemoteKey,
+ // Byte 2
+ AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
+ // Byte 3
+ Taproot,
+ // Byte 4
+ ,
+ // Byte 5
+ SCIDPrivacy,
+ // Byte 6
+ ZeroConf,
+ ]);
+
+ /// 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, $supported_getter: ident) => {
+ #[doc = $doc]
+ ///
+ /// See [BOLT #9] for details.
+ ///
+ /// [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
+ pub trait $feature: Context {
+ /// The bit used to signify that the feature is required.
+ const EVEN_BIT: usize = $odd_bit - 1;
+
+ /// The bit used to signify that the feature is optional.
+ const ODD_BIT: usize = $odd_bit;
+
+ /// Assertion that [`EVEN_BIT`] is actually even.
+ ///
+ /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
+ const ASSERT_EVEN_BIT_PARITY: usize;
+
+ /// Assertion that [`ODD_BIT`] is actually odd.
+ ///
+ /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
+ const ASSERT_ODD_BIT_PARITY: usize;
+
+ /// Assertion that the bits are set in the context's [`KNOWN_FEATURE_MASK`].
+ ///
+ /// [`KNOWN_FEATURE_MASK`]: Context::KNOWN_FEATURE_MASK
+ #[cfg(not(any(test, feature = "_test_utils")))] // We violate this constraint with `UnknownFeature`
+ const ASSERT_BITS_IN_MASK: u8;
+
+ /// The byte where the feature is set.
+ const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
+
+ /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
+ ///
+ /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
+ const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
+
+ /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
+ ///
+ /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
+ const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
+
+ /// Returns whether the feature is required by the given flags.
+ #[inline]
+ fn requires_feature(flags: &Vec<u8>) -> bool {
+ flags.len() > Self::BYTE_OFFSET &&
+ (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
+ }
+
+ /// Returns whether the feature is supported by the given flags.
+ #[inline]
+ fn supports_feature(flags: &Vec<u8>) -> bool {
+ flags.len() > Self::BYTE_OFFSET &&
+ (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
+ }
+
+ /// Sets the feature's required (even) bit in the given flags.
+ #[inline]
+ fn set_required_bit(flags: &mut Vec<u8>) {
+ if flags.len() <= Self::BYTE_OFFSET {
+ flags.resize(Self::BYTE_OFFSET + 1, 0u8);
+ }
+
+ flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
+ flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
+ }
+
+ /// Sets the feature's optional (odd) bit in the given flags.
+ #[inline]
+ fn set_optional_bit(flags: &mut Vec<u8>) {
+ if flags.len() <= Self::BYTE_OFFSET {
+ flags.resize(Self::BYTE_OFFSET + 1, 0u8);
+ }
+
+ flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
+ }
+
+ /// Clears the feature's required (even) and optional (odd) bits from the given
+ /// flags.
+ #[inline]
+ fn clear_bits(flags: &mut Vec<u8>) {
+ if flags.len() > Self::BYTE_OFFSET {
+ flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
+ flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
+ }
+
+ let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
+ let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
+ flags.resize(size, 0u8);
+ }
+ }
+
+ impl <T: $feature> Features<T> {
+ /// Set this feature as optional.
+ pub fn $optional_setter(&mut self) {
+ <T as $feature>::set_optional_bit(&mut self.flags);
+ }
+
+ /// Set this feature as required.
+ pub fn $required_setter(&mut self) {
+ <T as $feature>::set_required_bit(&mut self.flags);
+ }
+
+ /// Checks if this feature is supported.
+ pub fn $supported_getter(&self) -> bool {
+ <T as $feature>::supports_feature(&self.flags)
+ }
+ }
+
+ $(
+ impl $feature for $context {
+ // EVEN_BIT % 2 == 0
+ const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
+
+ // ODD_BIT % 2 == 1
+ const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
+
+ // (byte & (REQUIRED_MASK | OPTIONAL_MASK)) >> (EVEN_BIT % 8) == 3
+ #[cfg(not(any(test, feature = "_test_utils")))] // We violate this constraint with `UnknownFeature`
+ const ASSERT_BITS_IN_MASK: u8 =
+ ((<$context>::KNOWN_FEATURE_MASK[<Self as $feature>::BYTE_OFFSET] & (<Self as $feature>::REQUIRED_MASK | <Self as $feature>::OPTIONAL_MASK))
+ >> (<Self as $feature>::EVEN_BIT % 8)) - 3;
+ }
+ )*
+ };
+ ($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, 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,
+ 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, 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,
+ supports_gossip_queries, requires_gossip_queries);
+ define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, Bolt11InvoiceContext],
+ "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
+ 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, supports_static_remote_key, requires_static_remote_key);
+ define_feature!(15, PaymentSecret, [InitContext, NodeContext, Bolt11InvoiceContext],
+ "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, Bolt11InvoiceContext, Bolt12InvoiceContext],
+ "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
+ supports_basic_mpp, requires_basic_mpp);
+ define_feature!(19, Wumbo, [InitContext, NodeContext],
+ "Feature flags for `option_support_large_channel` (aka wumbo channels).", set_wumbo_optional, set_wumbo_required,
+ supports_wumbo, requires_wumbo);
+ define_feature!(21, AnchorsNonzeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
+ "Feature flags for `option_anchors_nonzero_fee_htlc_tx`.", set_anchors_nonzero_fee_htlc_tx_optional,
+ set_anchors_nonzero_fee_htlc_tx_required, supports_anchors_nonzero_fee_htlc_tx, requires_anchors_nonzero_fee_htlc_tx);
+ define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
+ "Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
+ set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
+ define_feature!(25, RouteBlinding, [InitContext, NodeContext],
+ "Feature flags for `option_route_blinding`.", set_route_blinding_optional,
+ set_route_blinding_required, supports_route_blinding, requires_route_blinding);
+ define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
+ "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
+ set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
+ define_feature!(31, Taproot, [InitContext, NodeContext, ChannelTypeContext],
+ "Feature flags for `option_taproot`.", set_taproot_optional,
+ set_taproot_required, supports_taproot, requires_taproot);
+ define_feature!(39, OnionMessages, [InitContext, NodeContext],
+ "Feature flags for `option_onion_messages`.", set_onion_messages_optional,
+ set_onion_messages_required, supports_onion_messages, requires_onion_messages);
+ 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!(47, SCIDPrivacy, [InitContext, NodeContext, ChannelTypeContext],
+ "Feature flags for only forwarding with SCID aliasing. Called `option_scid_alias` in the BOLTs",
+ set_scid_privacy_optional, set_scid_privacy_required, supports_scid_privacy, requires_scid_privacy);
+ define_feature!(49, PaymentMetadata, [Bolt11InvoiceContext],
+ "Feature flags for payment metadata in invoices.", set_payment_metadata_optional,
+ set_payment_metadata_required, supports_payment_metadata, requires_payment_metadata);
+ define_feature!(51, ZeroConf, [InitContext, NodeContext, ChannelTypeContext],
+ "Feature flags for accepting channels with zero confirmations. Called `option_zeroconf` in the BOLTs",
+ set_zero_conf_optional, set_zero_conf_required, supports_zero_conf, requires_zero_conf);
+ define_feature!(55, Keysend, [NodeContext],
+ "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
+ supports_keysend, requires_keysend);
+ define_feature!(57, Trampoline, [InitContext, NodeContext, Bolt11InvoiceContext],
+ "Feature flags for Trampoline routing.", set_trampoline_routing_optional, set_trampoline_routing_required,
+ supports_trampoline_routing, requires_trampoline_routing);
+ // Note: update the module-level docs when a new feature bit is added!
+
+ #[cfg(any(test, feature = "_test_utils"))]
+ define_feature!(123456789, UnknownFeature,
+ [NodeContext, ChannelContext, Bolt11InvoiceContext, OfferContext, InvoiceRequestContext, Bolt12InvoiceContext, BlindedHopContext],
+ "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
+ 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.
+///
+/// This is not exported to bindings users as we map the concrete feature types below directly instead
+#[derive(Eq)]
+pub struct Features<T: sealed::Context> {
+ /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
+ flags: Vec<u8>,
+ 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 {
+ self |= o;
+ self
+ }
+}
+
+impl<T: sealed::Context> Clone for Features<T> {
+ fn clone(&self) -> Self {
+ Self {
+ flags: self.flags.clone(),
+ mark: PhantomData,
+ }
+ }
+}
+impl<T: sealed::Context> Hash for Features<T> {
+ fn hash<H: Hasher>(&self, hasher: &mut H) {
+ let mut nonzero_flags = &self.flags[..];
+ while nonzero_flags.last() == Some(&0) {
+ nonzero_flags = &nonzero_flags[..nonzero_flags.len() - 1];
+ }
+ nonzero_flags.hash(hasher);
+ }
+}
+impl<T: sealed::Context> PartialEq for Features<T> {
+ fn eq(&self, o: &Self) -> bool {
+ let mut o_iter = o.flags.iter();
+ let mut self_iter = self.flags.iter();
+ loop {
+ match (o_iter.next(), self_iter.next()) {
+ (Some(o), Some(us)) => if o != us { return false },
+ (Some(b), None) | (None, Some(b)) => if *b != 0 { return false },
+ (None, None) => return true,
+ }
+ }
+ }
+}
+impl<T: sealed::Context> PartialOrd for Features<T> {
+ fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
+ self.flags.partial_cmp(&other.flags)
+ }
+}
+impl<T: sealed::Context + Eq> Ord for Features<T> {
+ fn cmp(&self, other: &Self) -> cmp::Ordering {
+ self.flags.cmp(&other.flags)
+ }
+}
+impl<T: sealed::Context> fmt::Debug for Features<T> {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+ self.flags.fmt(fmt)
+ }
+}
+
+/// Features used within an `init` message.
+pub type InitFeatures = Features<sealed::InitContext>;
+/// Features used within a `node_announcement` message.
+pub type NodeFeatures = Features<sealed::NodeContext>;
+/// Features used within a `channel_announcement` message.
+pub type ChannelFeatures = Features<sealed::ChannelContext>;
+/// Features used within an invoice.
+pub type Bolt11InvoiceFeatures = Features<sealed::Bolt11InvoiceContext>;
+/// Features used within an `offer`.
+pub type OfferFeatures = Features<sealed::OfferContext>;
+/// Features used within an `invoice_request`.
+pub type InvoiceRequestFeatures = Features<sealed::InvoiceRequestContext>;
+/// Features used within an `invoice`.
+pub type Bolt12InvoiceFeatures = Features<sealed::Bolt12InvoiceContext>;
+/// Features used within BOLT 4 encrypted_data_tlv and BOLT 12 blinded_payinfo
+pub type BlindedHopFeatures = Features<sealed::BlindedHopContext>;
+
+/// 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 {
+ #[doc(hidden)]
+ /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
+ /// are included in the result.
+ pub fn to_context<C: sealed::Context>(&self) -> Features<C> {
+ self.to_context_internal()
+ }
+}
+
+impl Bolt11InvoiceFeatures {
+ #[doc(hidden)]
+ /// Converts `Bolt11InvoiceFeatures` to `Features<C>`. Only known `Bolt11InvoiceFeatures` relevant to
+ /// context `C` are included in the result.
+ pub 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
+ /// when a [`Bolt11InvoiceFeatures`] is required in a route.
+ ///
+ /// MPP keysend is not widely supported yet, so we parameterize support to allow the user to
+ /// choose whether their router should find multi-part routes.
+ pub fn for_keysend(allow_mpp: bool) -> Bolt11InvoiceFeatures {
+ let mut res = Bolt11InvoiceFeatures::empty();
+ res.set_variable_length_onion_optional();
+ if allow_mpp {
+ res.set_basic_mpp_optional();
+ }
+ res
+ }
+}
+
+impl Bolt12InvoiceFeatures {
+ #[doc(hidden)]
+ /// Converts [`Bolt12InvoiceFeatures`] to [`Features<C>`]. Only known [`Bolt12InvoiceFeatures`]
+ /// relevant to context `C` are included in the result.
+ pub fn to_context<C: sealed::Context>(&self) -> Features<C> {
+ self.to_context_internal()
+ }
+}
+
+impl ChannelTypeFeatures {
+ #[doc(hidden)]
+ // Maps the relevant `InitFeatures` to `ChannelTypeFeatures`. Any unknown features to
+ // `ChannelTypeFeatures` are not included in the result.
+ pub fn from_init(init: &InitFeatures) -> Self {
+ let mut ret = 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 & ANY_OPTIONAL_FEATURES_MASK) >> 1;
+ *byte &= ANY_REQUIRED_FEATURES_MASK;
+ }
+ ret
+ }
+
+ /// Constructs a ChannelTypeFeatures with only static_remotekey set
+ pub fn only_static_remote_key() -> Self {
+ let mut ret = Self::empty();
+ <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
+ ret
+ }
+
+ /// Constructs a ChannelTypeFeatures with anchors support
+ pub 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 Bolt11InvoiceFeatures {
+ 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
+ // minus one before dividing
+ let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
+ let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
+ for (byte_idx, byte) in self.flags.iter().enumerate() {
+ let bit_pos_from_left_0_indexed = byte_idx * 8;
+ let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
+ let new_bit_pos = bit_pos_from_left_0_indexed % 5;
+ let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
+ let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
+ res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
+ if new_u5_idx > 0 {
+ let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
+ res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
+ }
+ if new_u5_idx > 1 {
+ let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
+ res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
+ }
+ }
+ // Trim the highest feature bits.
+ while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
+ res_u5s.remove(0);
+ }
+ writer.write(&res_u5s)
+ }
+}
+
+impl Base32Len for Bolt11InvoiceFeatures {
+ fn base32_len(&self) -> usize {
+ self.to_base32().len()
+ }
+}
+
+impl FromBase32 for Bolt11InvoiceFeatures {
+ type Err = bech32::Error;
+
+ fn from_base32(field_data: &[u5]) -> Result<Bolt11InvoiceFeatures, bech32::Error> {
+ // Explanation for the "7": the normal way to round up when dividing is to add the divisor
+ // minus one before dividing
+ let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
+ let mut res_bytes: Vec<u8> = vec![0; length_bytes];
+ for (u5_idx, chunk) in field_data.iter().enumerate() {
+ let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
+ let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
+ let new_bit_pos = bit_pos_from_right_0_indexed % 8;
+ let chunk_u16 = chunk.to_u8() as u16;
+ res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
+ if new_byte_idx != length_bytes - 1 {
+ res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
+ }
+ }
+ // Trim the highest feature bits.
+ while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
+ res_bytes.pop();
+ }
+ Ok(Bolt11InvoiceFeatures::from_le_bytes(res_bytes))
+ }
+}
+
+impl<T: sealed::Context> Features<T> {
+ /// Create a blank Features with no features set
+ pub fn empty() -> Self {
+ Features {
+ flags: Vec::new(),
+ mark: PhantomData,
+ }
+ }
+
+ /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
+ /// included in the result.
+ fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
+ let from_byte_count = T::KNOWN_FEATURE_MASK.len();
+ let to_byte_count = C::KNOWN_FEATURE_MASK.len();
+ let mut flags = Vec::new();
+ for (i, byte) in self.flags.iter().enumerate() {
+ if i < from_byte_count && i < to_byte_count {
+ let from_known_features = T::KNOWN_FEATURE_MASK[i];
+ let to_known_features = C::KNOWN_FEATURE_MASK[i];
+ flags.push(byte & from_known_features & to_known_features);
+ }
+ }
+ Features::<C> { flags, mark: PhantomData, }
+ }
+
+ /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
+ /// most on-the-wire encodings.
+ ///
+ /// This is not exported to bindings users as we don't support export across multiple T
+ pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
+ Features {
+ flags,
+ mark: PhantomData,
+ }
+ }
+
+ /// Returns the feature set as a list of bytes, in little-endian. This is in reverse byte order
+ /// from most on-the-wire encodings.
+ pub fn le_flags(&self) -> &[u8] {
+ &self.flags
+ }
+
+ /// Create a [`Features`] given a set of flags, in big-endian. This is in byte order from
+ /// most on-the-wire encodings.
+ ///
+ /// This is not exported to bindings users as we don't support export across multiple T
+ pub fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
+ flags.reverse(); // Swap to little-endian
+ Self {
+ flags,
+ mark: PhantomData,
+ }
+ }
+
+ /// Returns true if this `Features` has any optional flags set
+ pub fn supports_any_optional_bits(&self) -> bool {
+ self.flags.iter().any(|&byte| (byte & ANY_OPTIONAL_FEATURES_MASK) != 0)
+ }
+
+ /// Returns true if this `Features` object contains required features unknown by `other`.
+ pub fn requires_unknown_bits_from(&self, other: &Self) -> bool {
+ // Bitwise AND-ing with all even bits set except for known features will select required
+ // unknown features.
+ self.flags.iter().enumerate().any(|(i, &byte)| {
+ let unknown_features = unset_features_mask_at_position(other, i);
+ (byte & (ANY_REQUIRED_FEATURES_MASK & unknown_features)) != 0
+ })
+ }
+
+ /// Returns the set of required features unknown by `other`, as their bit position.
+ pub fn required_unknown_bits_from(&self, other: &Self) -> Vec<usize> {
+ let mut unknown_bits = Vec::new();
+
+ // 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)| {
+ 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 {
+ unknown_bits.push(i * 8 + bit);
+ }
+ }
+ }
+ });
+
+ unknown_bits
+ }
+
+ /// 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 mut known_chunks = T::KNOWN_FEATURE_MASK.chunks(8);
+ for chunk in self.flags.chunks(8) {
+ let mut flag_bytes = [0; 8];
+ flag_bytes[..chunk.len()].copy_from_slice(&chunk);
+ let flag_int = u64::from_le_bytes(flag_bytes);
+
+ let known_chunk = known_chunks.next().unwrap_or(&[0; 0]);
+ let mut known_bytes = [0; 8];
+ known_bytes[..known_chunk.len()].copy_from_slice(&known_chunk);
+ let known_int = u64::from_le_bytes(known_bytes);
+
+ const REQ_MASK: u64 = u64::from_le_bytes([ANY_REQUIRED_FEATURES_MASK; 8]);
+ if flag_int & (REQ_MASK & !known_int) != 0 {
+ return true;
+ }
+ }
+ false
+ }
+
+ /// Returns true if this `Features` supports any bits which we do not know of
+ pub fn supports_unknown_bits(&self) -> bool {
+ // Bitwise AND-ing with all even and odd bits set except for known features will select
+ // both required and optional unknown features.
+ let byte_count = T::KNOWN_FEATURE_MASK.len();
+ self.flags.iter().enumerate().any(|(i, &byte)| {
+ let unknown_features = if i < byte_count {
+ !T::KNOWN_FEATURE_MASK[i]
+ } else {
+ 0b11_11_11_11
+ };
+ (byte & unknown_features) != 0
+ })
+ }
+
+ /// Sets a required feature bit. Errors if `bit` is outside the feature range as defined
+ /// by [BOLT 9].
+ ///
+ /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
+ /// be set instead (i.e., `bit - 1`).
+ ///
+ /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
+ pub fn set_required_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+ self.set_feature_bit(bit - (bit % 2))
+ }
+
+ /// Sets an optional feature bit. Errors if `bit` is outside the feature range as defined
+ /// by [BOLT 9].
+ ///
+ /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
+ /// set instead (i.e., `bit + 1`).
+ ///
+ /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
+ pub fn set_optional_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+ self.set_feature_bit(bit + (1 - (bit % 2)))
+ }
+
+ fn set_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+ if bit > 255 {
+ return Err(());
+ }
+ self.set_bit(bit, false)
+ }
+
+ /// Sets a required custom feature bit. Errors if `bit` is outside the custom range as defined
+ /// by [bLIP 2] or if it is a known `T` feature.
+ ///
+ /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
+ /// be set instead (i.e., `bit - 1`).
+ ///
+ /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
+ pub fn set_required_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
+ self.set_custom_bit(bit - (bit % 2))
+ }
+
+ /// Sets an optional custom feature bit. Errors if `bit` is outside the custom range as defined
+ /// by [bLIP 2] or if it is a known `T` feature.
+ ///
+ /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
+ /// set instead (i.e., `bit + 1`).
+ ///
+ /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
+ pub fn set_optional_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
+ self.set_custom_bit(bit + (1 - (bit % 2)))
+ }
+
+ fn set_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
+ if bit < 256 {
+ return Err(());
+ }
+ self.set_bit(bit, true)
+ }
+
+ fn set_bit(&mut self, bit: usize, custom: bool) -> Result<(), ()> {
+ let byte_offset = bit / 8;
+ let mask = 1 << (bit - 8 * byte_offset);
+ if byte_offset < T::KNOWN_FEATURE_MASK.len() && custom {
+ if (T::KNOWN_FEATURE_MASK[byte_offset] & mask) != 0 {
+ return Err(());
+ }
+ }
+
+ if self.flags.len() <= byte_offset {
+ self.flags.resize(byte_offset + 1, 0u8);
+ }
+
+ self.flags[byte_offset] |= mask;
+
+ Ok(())
+ }
+}
+
+impl<T: sealed::UpfrontShutdownScript> Features<T> {
+ /// Unsets the `upfront_shutdown_script` feature
+ pub fn clear_upfront_shutdown_script(mut self) -> Self {
+ <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
+ self
+ }
+}
+
+impl<T: sealed::ShutdownAnySegwit> Features<T> {
+ /// Unsets the `shutdown_anysegwit` feature
+ pub fn clear_shutdown_anysegwit(mut self) -> Self {
+ <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
+ self
+ }
+}
+
+impl<T: sealed::Wumbo> Features<T> {
+ /// Unsets the `wumbo` feature
+ pub fn clear_wumbo(mut self) -> Self {
+ <T as sealed::Wumbo>::clear_bits(&mut self.flags);
+ self
+ }
+}
+
+impl<T: sealed::SCIDPrivacy> Features<T> {
+ /// Unsets the `scid_privacy` feature
+ pub fn clear_scid_privacy(&mut self) {
+ <T as sealed::SCIDPrivacy>::clear_bits(&mut self.flags);
+ }
+}
+
+impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
+ /// Unsets the `anchors_zero_fee_htlc_tx` feature
+ pub fn clear_anchors_zero_fee_htlc_tx(&mut self) {
+ <T as sealed::AnchorsZeroFeeHtlcTx>::clear_bits(&mut self.flags);
+ }
+}
+
+impl<T: sealed::RouteBlinding> Features<T> {
+ /// Unsets the `route_blinding` feature
+ pub fn clear_route_blinding(&mut self) {
+ <T as sealed::RouteBlinding>::clear_bits(&mut self.flags);
+ }
+}
+
+#[cfg(any(test, feature = "_test_utils"))]
+impl<T: sealed::UnknownFeature> Features<T> {
+ /// Sets an unknown feature for testing
+ pub fn unknown() -> Self {
+ let mut features = Self::empty();
+ features.set_unknown_feature_required();
+ features
+ }
+}
+
+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::*;
+
+ #[test]
+ fn sanity_test_unknown_bits() {
+ let features = ChannelFeatures::empty();
+ assert!(!features.requires_unknown_bits());
+ assert!(!features.supports_unknown_bits());
+
+ let mut features = ChannelFeatures::empty();
+ features.set_unknown_feature_required();
+ assert!(features.requires_unknown_bits());
+ assert!(features.supports_unknown_bits());
+ assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456788]);
+
+ let mut features = ChannelFeatures::empty();
+ features.set_unknown_feature_optional();
+ assert!(!features.requires_unknown_bits());
+ assert!(features.supports_unknown_bits());
+ assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![]);
+
+ let mut features = ChannelFeatures::empty();
+ features.set_unknown_feature_required();
+ features.set_custom_bit(123456786).unwrap();
+ assert!(features.requires_unknown_bits());
+ assert!(features.supports_unknown_bits());
+ assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456786, 123456788]);
+
+ let mut limiter = ChannelFeatures::empty();
+ limiter.set_unknown_feature_optional();
+ assert_eq!(features.required_unknown_bits_from(&limiter), vec![123456786]);
+ }
+
+ #[test]
+ fn requires_unknown_bits_from() {
+ let mut features1 = InitFeatures::empty();
+ let mut features2 = InitFeatures::empty();
+ assert!(!features1.requires_unknown_bits_from(&features2));
+ assert!(!features2.requires_unknown_bits_from(&features1));
+
+ features1.set_data_loss_protect_required();
+ assert!(features1.requires_unknown_bits_from(&features2));
+ assert!(!features2.requires_unknown_bits_from(&features1));
+
+ features2.set_data_loss_protect_optional();
+ assert!(!features1.requires_unknown_bits_from(&features2));
+ assert!(!features2.requires_unknown_bits_from(&features1));
+
+ features2.set_gossip_queries_required();
+ assert!(!features1.requires_unknown_bits_from(&features2));
+ assert!(features2.requires_unknown_bits_from(&features1));
+
+ features1.set_gossip_queries_optional();
+ assert!(!features1.requires_unknown_bits_from(&features2));
+ assert!(!features2.requires_unknown_bits_from(&features1));
+
+ features1.set_variable_length_onion_required();
+ assert!(features1.requires_unknown_bits_from(&features2));
+ assert!(!features2.requires_unknown_bits_from(&features1));
+
+ features2.set_variable_length_onion_optional();
+ assert!(!features1.requires_unknown_bits_from(&features2));
+ assert!(!features2.requires_unknown_bits_from(&features1));
+
+ features1.set_basic_mpp_required();
+ features2.set_wumbo_required();
+ assert!(features1.requires_unknown_bits_from(&features2));
+ assert!(features2.requires_unknown_bits_from(&features1));
+ }
+
+ #[test]
+ fn convert_to_context_with_relevant_flags() {
+ let mut init_features = InitFeatures::empty();
+ // Set a bunch of features we use, plus initial_routing_sync_required (which shouldn't get
+ // converted as it's only relevant in an init context).
+ init_features.set_initial_routing_sync_required();
+ init_features.set_data_loss_protect_required();
+ init_features.set_variable_length_onion_required();
+ init_features.set_static_remote_key_required();
+ init_features.set_payment_secret_required();
+ init_features.set_basic_mpp_optional();
+ init_features.set_wumbo_optional();
+ init_features.set_anchors_zero_fee_htlc_tx_optional();
+ init_features.set_route_blinding_optional();
+ init_features.set_shutdown_any_segwit_optional();
+ init_features.set_onion_messages_optional();
+ init_features.set_channel_type_optional();
+ init_features.set_scid_privacy_optional();
+ init_features.set_zero_conf_optional();
+
+ assert!(init_features.initial_routing_sync());
+ assert!(!init_features.supports_upfront_shutdown_script());
+ assert!(!init_features.supports_gossip_queries());
+
+ let node_features: NodeFeatures = init_features.to_context();
+ {
+ // Check that the flags are as expected:
+ // - option_data_loss_protect (req)
+ // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
+ // - basic_mpp | wumbo | option_anchors_zero_fee_htlc_tx
+ // - option_route_blinding | opt_shutdown_anysegwit
+ // - onion_messages
+ // - option_channel_type | option_scid_alias
+ // - option_zeroconf
+ assert_eq!(node_features.flags.len(), 7);
+ assert_eq!(node_features.flags[0], 0b00000001);
+ assert_eq!(node_features.flags[1], 0b01010001);
+ assert_eq!(node_features.flags[2], 0b10001010);
+ assert_eq!(node_features.flags[3], 0b00001010);
+ assert_eq!(node_features.flags[4], 0b10000000);
+ assert_eq!(node_features.flags[5], 0b10100000);
+ assert_eq!(node_features.flags[6], 0b00001000);
+ }
+
+ // Check that cleared flags are kept blank when converting back:
+ // - initial_routing_sync was not applicable to NodeContext
+ // - upfront_shutdown_script was cleared before converting
+ // - gossip_queries was cleared before converting
+ let features: InitFeatures = node_features.to_context_internal();
+ assert!(!features.initial_routing_sync());
+ assert!(!features.supports_upfront_shutdown_script());
+ assert!(!init_features.supports_gossip_queries());
+ }
+
+ #[test]
+ fn convert_to_context_with_unknown_flags() {
+ // Ensure the `from` context has fewer known feature bytes than the `to` context.
+ assert!(<sealed::ChannelContext as sealed::Context>::KNOWN_FEATURE_MASK.len() <
+ <sealed::Bolt11InvoiceContext as sealed::Context>::KNOWN_FEATURE_MASK.len());
+ let mut channel_features = ChannelFeatures::empty();
+ channel_features.set_unknown_feature_optional();
+ assert!(channel_features.supports_unknown_bits());
+ let invoice_features: Bolt11InvoiceFeatures = channel_features.to_context_internal();
+ assert!(!invoice_features.supports_unknown_bits());
+ }
+
+ #[test]
+ fn set_feature_bits() {
+ let mut features = Bolt11InvoiceFeatures::empty();
+ features.set_basic_mpp_optional();
+ features.set_payment_secret_required();
+ assert!(features.supports_basic_mpp());
+ assert!(!features.requires_basic_mpp());
+ assert!(features.requires_payment_secret());
+ assert!(features.supports_payment_secret());
+
+ // Set flags manually
+ let mut features = NodeFeatures::empty();
+ assert!(features.set_optional_feature_bit(55).is_ok());
+ assert!(features.supports_keysend());
+ assert!(features.set_optional_feature_bit(255).is_ok());
+ assert!(features.set_required_feature_bit(256).is_err());
+ }
+
+ #[test]
+ fn set_custom_bits() {
+ let mut features = Bolt11InvoiceFeatures::empty();
+ features.set_variable_length_onion_optional();
+ assert_eq!(features.flags[1], 0b00000010);
+
+ assert!(features.set_optional_custom_bit(255).is_err());
+ assert!(features.set_required_custom_bit(256).is_ok());
+ assert!(features.set_required_custom_bit(258).is_ok());
+ assert_eq!(features.flags[31], 0b00000000);
+ assert_eq!(features.flags[32], 0b00000101);
+
+ let known_bit = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::EVEN_BIT;
+ let byte_offset = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::BYTE_OFFSET;
+ assert_eq!(byte_offset, 1);
+ assert_eq!(features.flags[byte_offset], 0b00000010);
+ assert!(features.set_required_custom_bit(known_bit).is_err());
+ assert_eq!(features.flags[byte_offset], 0b00000010);
+
+ let mut features = Bolt11InvoiceFeatures::empty();
+ assert!(features.set_optional_custom_bit(256).is_ok());
+ assert!(features.set_optional_custom_bit(259).is_ok());
+ assert_eq!(features.flags[32], 0b00001010);
+
+ let mut features = Bolt11InvoiceFeatures::empty();
+ assert!(features.set_required_custom_bit(257).is_ok());
+ assert!(features.set_required_custom_bit(258).is_ok());
+ assert_eq!(features.flags[32], 0b00000101);
+ }
+
+ #[test]
+ fn invoice_features_encoding() {
+ let features_as_u5s = vec![
+ u5::try_from_u8(6).unwrap(),
+ u5::try_from_u8(10).unwrap(),
+ u5::try_from_u8(25).unwrap(),
+ u5::try_from_u8(1).unwrap(),
+ u5::try_from_u8(10).unwrap(),
+ u5::try_from_u8(0).unwrap(),
+ u5::try_from_u8(20).unwrap(),
+ u5::try_from_u8(2).unwrap(),
+ u5::try_from_u8(0).unwrap(),
+ u5::try_from_u8(6).unwrap(),
+ u5::try_from_u8(0).unwrap(),
+ u5::try_from_u8(16).unwrap(),
+ u5::try_from_u8(1).unwrap(),
+ ];
+ let features = Bolt11InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
+
+ // Test length calculation.
+ assert_eq!(features.base32_len(), 13);
+
+ // Test serialization.
+ let features_serialized = features.to_base32();
+ assert_eq!(features_as_u5s, features_serialized);
+
+ // Test deserialization.
+ let features_deserialized = Bolt11InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
+ assert_eq!(features, features_deserialized);
+ }
+
+ #[test]
+ fn test_channel_type_mapping() {
+ // If we map an Bolt11InvoiceFeatures with StaticRemoteKey optional, it should map into a
+ // required-StaticRemoteKey ChannelTypeFeatures.
+ let mut init_features = InitFeatures::empty();
+ init_features.set_static_remote_key_optional();
+ let converted_features = ChannelTypeFeatures::from_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());
+ }
+
+ #[test]
+ fn test_excess_zero_bytes_ignored() {
+ // Checks that `Hash` and `PartialEq` ignore excess zero bytes, which may appear due to
+ // feature conversion or because a peer serialized their feature poorly.
+ use std::collections::hash_map::DefaultHasher;
+ use std::hash::{Hash, Hasher};
+
+ let mut zerod_features = InitFeatures::empty();
+ zerod_features.flags = vec![0];
+ let empty_features = InitFeatures::empty();
+ assert!(empty_features.flags.is_empty());
+
+ assert_eq!(zerod_features, empty_features);
+
+ let mut zerod_hash = DefaultHasher::new();
+ zerod_features.hash(&mut zerod_hash);
+ let mut empty_hash = DefaultHasher::new();
+ empty_features.hash(&mut empty_hash);
+ assert_eq!(zerod_hash.finish(), empty_hash.finish());
+ }
+}
//! Feature flag definitions for the Lightning protocol according to [BOLT #9].
//!
-//! Lightning nodes advertise a supported set of operation through feature flags. Features are
-//! applicable for a specific context as indicated in some [messages]. [`Features`] encapsulates
-//! behavior for specifying and checking feature flags for a particular context. Each feature is
-//! defined internally by a trait specifying the corresponding flags (i.e., even and odd bits).
-//!
-//! Whether a feature is considered "known" or "unknown" is relative to the implementation, whereas
-//! the term "supports" is used in reference to a particular set of [`Features`]. That is, a node
-//! supports a feature if it advertises the feature (as either required or optional) to its peers.
-//! And the implementation can interpret a feature if the feature is known to it.
-//!
-//! The following features are currently required in the LDK:
-//! - `VariableLengthOnion` - requires/supports variable-length routing onion payloads
-//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md) for more information).
-//! - `StaticRemoteKey` - requires/supports static key for remote output
-//! (see [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more information).
-//!
-//! The following features are currently supported in the LDK:
-//! - `DataLossProtect` - requires/supports that a node which has somehow fallen behind, e.g., has been restored from an old backup,
-//! can detect that it has fallen behind
-//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
-//! - `InitialRoutingSync` - requires/supports that the sending node needs a complete routing information dump
-//! (see [BOLT-7](https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#initial-sync) for more information).
-//! - `UpfrontShutdownScript` - commits to a shutdown scriptpubkey when opening a channel
-//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
-//! - `GossipQueries` - requires/supports more sophisticated gossip control
-//! (see [BOLT-7](https://github.com/lightning/bolts/blob/master/07-routing-gossip.md) for more information).
-//! - `PaymentSecret` - requires/supports that a node supports payment_secret field
-//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md) for more information).
-//! - `BasicMPP` - requires/supports that a node can receive basic multi-part payments
-//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#basic-multi-part-payments) for more information).
-//! - `Wumbo` - requires/supports that a node create large channels. Called `option_support_large_channel` in the spec.
-//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
-//! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
-//! and HTLC transactions are pre-signed with zero fee (see
-//! [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
-//! information).
-//! - `RouteBlinding` - requires/supports that a node can relay payments over blinded paths
-//! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#route-blinding) for more information).
-//! - `ShutdownAnySegwit` - requires/supports that future segwit versions are allowed in `shutdown`
-//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
-//! - `OnionMessages` - requires/supports forwarding onion messages
-//! (see [BOLT-7](https://github.com/lightning/bolts/pull/759/files) for more information).
-// TODO: update link
-//! - `ChannelType` - node supports the channel_type field in open/accept
-//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
-//! - `SCIDPrivacy` - supply channel aliases for routing
-//! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
-//! - `PaymentMetadata` - include additional data in invoices which is passed to recipients in the
-//! onion.
-//! (see [BOLT-11](https://github.com/lightning/bolts/blob/master/11-payment-encoding.md) for
-//! more).
-//! - `ZeroConf` - supports accepting HTLCs and using channels prior to funding confirmation
-//! (see
-//! [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-channel_ready-message)
-//! for more info).
-//! - `Keysend` - send funds to a node without an invoice
-//! (see the [`Keysend` feature assignment proposal](https://github.com/lightning/bolts/issues/605#issuecomment-606679798) for more information).
-//! - `Trampoline` - supports receiving and forwarding Trampoline payments
-//! (see the [`Trampoline` feature proposal](https://github.com/lightning/bolts/pull/836) 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).
+//! See [`lightning_types::features`] for the list of features currently supported.
//!
//! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
-//! [messages]: crate::ln::msgs
+
+pub use lightning_types::features::Features;
+pub use lightning_types::features::{InitFeatures, NodeFeatures, ChannelFeatures};
+pub use lightning_types::features::{Bolt11InvoiceFeatures, OfferFeatures, InvoiceRequestFeatures};
+pub use lightning_types::features::{Bolt12InvoiceFeatures, BlindedHopFeatures};
+pub use lightning_types::features::ChannelTypeFeatures;
#[allow(unused_imports)]
use crate::prelude::*;
use crate::{io, io_extras};
-use core::{cmp, fmt};
-use core::borrow::Borrow;
-use core::hash::{Hash, Hasher};
-use core::marker::PhantomData;
-
-use bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
use crate::ln::msgs::DecodeError;
-use crate::util::ser::{Readable, WithoutLength, Writeable, Writer};
-
-mod sealed {
- #[allow(unused_imports)]
- use crate::prelude::*;
- use crate::ln::features::Features;
-
- /// The context in which [`Features`] are applicable. Defines which features are known to the
- /// implementation, though specification of them as required or optional is up to the code
- /// constructing a features object.
- pub trait Context {
- /// Bitmask for selecting features that are known to the implementation.
- const KNOWN_FEATURE_MASK: &'static [u8];
- }
-
- /// Defines a [`Context`] by stating which features it requires and which are optional. Features
- /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
- /// feature identifiers.
- macro_rules! define_context {
- ($context: ident, [$( $( $known_feature: ident )|*, )*]) => {
- #[derive(Eq, PartialEq)]
- pub struct $context {}
-
- impl Context for $context {
- const KNOWN_FEATURE_MASK: &'static [u8] = &[
- $(
- 0b00_00_00_00 $(|
- <Self as $known_feature>::REQUIRED_MASK |
- <Self as $known_feature>::OPTIONAL_MASK)*,
- )*
- ];
- }
-
- impl alloc::fmt::Display for Features<$context> {
- fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
- $(
- $(
- fmt.write_fmt(format_args!("{}: {}, ", stringify!($known_feature),
- if <$context as $known_feature>::requires_feature(&self.flags) { "required" }
- else if <$context as $known_feature>::supports_feature(&self.flags) { "supported" }
- else { "not supported" }))?;
- )*
- {} // Rust gets mad if we only have a $()* block here, so add a dummy {}
- )*
- fmt.write_fmt(format_args!("unknown flags: {}",
- if self.requires_unknown_bits() { "required" }
- else if self.supports_unknown_bits() { "supported" } else { "none" }))
- }
- }
- };
- }
-
- define_context!(InitContext, [
- // Byte 0
- DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
- // Byte 1
- VariableLengthOnion | StaticRemoteKey | PaymentSecret,
- // Byte 2
- BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
- // Byte 3
- RouteBlinding | ShutdownAnySegwit | Taproot,
- // Byte 4
- OnionMessages,
- // Byte 5
- ChannelType | SCIDPrivacy,
- // Byte 6
- ZeroConf,
- // Byte 7
- Trampoline,
- ]);
- define_context!(NodeContext, [
- // Byte 0
- DataLossProtect | UpfrontShutdownScript | GossipQueries,
- // Byte 1
- VariableLengthOnion | StaticRemoteKey | PaymentSecret,
- // Byte 2
- BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
- // Byte 3
- RouteBlinding | ShutdownAnySegwit | Taproot,
- // Byte 4
- OnionMessages,
- // Byte 5
- ChannelType | SCIDPrivacy,
- // Byte 6
- ZeroConf | Keysend,
- // Byte 7
- Trampoline,
- ]);
- define_context!(ChannelContext, []);
- define_context!(Bolt11InvoiceContext, [
- // Byte 0
- ,
- // Byte 1
- VariableLengthOnion | PaymentSecret,
- // Byte 2
- BasicMPP,
- // Byte 3
- ,
- // Byte 4
- ,
- // Byte 5
- ,
- // Byte 6
- PaymentMetadata,
- // Byte 7
- Trampoline,
- ]);
- define_context!(OfferContext, []);
- define_context!(InvoiceRequestContext, []);
- define_context!(Bolt12InvoiceContext, [
- // Byte 0
- ,
- // Byte 1
- ,
- // Byte 2
- BasicMPP,
- ]);
- define_context!(BlindedHopContext, []);
- // This isn't a "real" feature context, and is only used in the channel_type field in an
- // `OpenChannel` message.
- define_context!(ChannelTypeContext, [
- // Byte 0
- ,
- // Byte 1
- StaticRemoteKey,
- // Byte 2
- AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
- // Byte 3
- Taproot,
- // Byte 4
- ,
- // Byte 5
- SCIDPrivacy,
- // Byte 6
- ZeroConf,
- ]);
-
- /// 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, $supported_getter: ident) => {
- #[doc = $doc]
- ///
- /// See [BOLT #9] for details.
- ///
- /// [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
- pub trait $feature: Context {
- /// The bit used to signify that the feature is required.
- const EVEN_BIT: usize = $odd_bit - 1;
-
- /// The bit used to signify that the feature is optional.
- const ODD_BIT: usize = $odd_bit;
-
- /// Assertion that [`EVEN_BIT`] is actually even.
- ///
- /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
- const ASSERT_EVEN_BIT_PARITY: usize;
-
- /// Assertion that [`ODD_BIT`] is actually odd.
- ///
- /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
- const ASSERT_ODD_BIT_PARITY: usize;
-
- /// Assertion that the bits are set in the context's [`KNOWN_FEATURE_MASK`].
- ///
- /// [`KNOWN_FEATURE_MASK`]: Context::KNOWN_FEATURE_MASK
- #[cfg(not(test))] // We violate this constraint with `UnknownFeature`
- const ASSERT_BITS_IN_MASK: u8;
-
- /// The byte where the feature is set.
- const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
-
- /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
- ///
- /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
- const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
-
- /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
- ///
- /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
- const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
-
- /// Returns whether the feature is required by the given flags.
- #[inline]
- fn requires_feature(flags: &Vec<u8>) -> bool {
- flags.len() > Self::BYTE_OFFSET &&
- (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
- }
-
- /// Returns whether the feature is supported by the given flags.
- #[inline]
- fn supports_feature(flags: &Vec<u8>) -> bool {
- flags.len() > Self::BYTE_OFFSET &&
- (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
- }
-
- /// Sets the feature's required (even) bit in the given flags.
- #[inline]
- fn set_required_bit(flags: &mut Vec<u8>) {
- if flags.len() <= Self::BYTE_OFFSET {
- flags.resize(Self::BYTE_OFFSET + 1, 0u8);
- }
-
- flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
- flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
- }
-
- /// Sets the feature's optional (odd) bit in the given flags.
- #[inline]
- fn set_optional_bit(flags: &mut Vec<u8>) {
- if flags.len() <= Self::BYTE_OFFSET {
- flags.resize(Self::BYTE_OFFSET + 1, 0u8);
- }
-
- flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
- }
-
- /// Clears the feature's required (even) and optional (odd) bits from the given
- /// flags.
- #[inline]
- fn clear_bits(flags: &mut Vec<u8>) {
- if flags.len() > Self::BYTE_OFFSET {
- flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
- flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
- }
-
- let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
- let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
- flags.resize(size, 0u8);
- }
- }
-
- impl <T: $feature> Features<T> {
- /// Set this feature as optional.
- pub fn $optional_setter(&mut self) {
- <T as $feature>::set_optional_bit(&mut self.flags);
- }
-
- /// Set this feature as required.
- pub fn $required_setter(&mut self) {
- <T as $feature>::set_required_bit(&mut self.flags);
- }
-
- /// Checks if this feature is supported.
- pub fn $supported_getter(&self) -> bool {
- <T as $feature>::supports_feature(&self.flags)
- }
- }
-
- $(
- impl $feature for $context {
- // EVEN_BIT % 2 == 0
- const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
-
- // ODD_BIT % 2 == 1
- const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
-
- // (byte & (REQUIRED_MASK | OPTIONAL_MASK)) >> (EVEN_BIT % 8) == 3
- #[cfg(not(test))] // We violate this constraint with `UnknownFeature`
- const ASSERT_BITS_IN_MASK: u8 =
- ((<$context>::KNOWN_FEATURE_MASK[<Self as $feature>::BYTE_OFFSET] & (<Self as $feature>::REQUIRED_MASK | <Self as $feature>::OPTIONAL_MASK))
- >> (<Self as $feature>::EVEN_BIT % 8)) - 3;
- }
- )*
- };
- ($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, 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,
- 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, 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,
- supports_gossip_queries, requires_gossip_queries);
- define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, Bolt11InvoiceContext],
- "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
- 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, supports_static_remote_key, requires_static_remote_key);
- define_feature!(15, PaymentSecret, [InitContext, NodeContext, Bolt11InvoiceContext],
- "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, Bolt11InvoiceContext, Bolt12InvoiceContext],
- "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
- supports_basic_mpp, requires_basic_mpp);
- define_feature!(19, Wumbo, [InitContext, NodeContext],
- "Feature flags for `option_support_large_channel` (aka wumbo channels).", set_wumbo_optional, set_wumbo_required,
- supports_wumbo, requires_wumbo);
- define_feature!(21, AnchorsNonzeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
- "Feature flags for `option_anchors_nonzero_fee_htlc_tx`.", set_anchors_nonzero_fee_htlc_tx_optional,
- set_anchors_nonzero_fee_htlc_tx_required, supports_anchors_nonzero_fee_htlc_tx, requires_anchors_nonzero_fee_htlc_tx);
- define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
- "Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
- set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
- define_feature!(25, RouteBlinding, [InitContext, NodeContext],
- "Feature flags for `option_route_blinding`.", set_route_blinding_optional,
- set_route_blinding_required, supports_route_blinding, requires_route_blinding);
- define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
- "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
- set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
- define_feature!(31, Taproot, [InitContext, NodeContext, ChannelTypeContext],
- "Feature flags for `option_taproot`.", set_taproot_optional,
- set_taproot_required, supports_taproot, requires_taproot);
- define_feature!(39, OnionMessages, [InitContext, NodeContext],
- "Feature flags for `option_onion_messages`.", set_onion_messages_optional,
- set_onion_messages_required, supports_onion_messages, requires_onion_messages);
- 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!(47, SCIDPrivacy, [InitContext, NodeContext, ChannelTypeContext],
- "Feature flags for only forwarding with SCID aliasing. Called `option_scid_alias` in the BOLTs",
- set_scid_privacy_optional, set_scid_privacy_required, supports_scid_privacy, requires_scid_privacy);
- define_feature!(49, PaymentMetadata, [Bolt11InvoiceContext],
- "Feature flags for payment metadata in invoices.", set_payment_metadata_optional,
- set_payment_metadata_required, supports_payment_metadata, requires_payment_metadata);
- define_feature!(51, ZeroConf, [InitContext, NodeContext, ChannelTypeContext],
- "Feature flags for accepting channels with zero confirmations. Called `option_zeroconf` in the BOLTs",
- set_zero_conf_optional, set_zero_conf_required, supports_zero_conf, requires_zero_conf);
- define_feature!(55, Keysend, [NodeContext],
- "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
- supports_keysend, requires_keysend);
- define_feature!(57, Trampoline, [InitContext, NodeContext, Bolt11InvoiceContext],
- "Feature flags for Trampoline routing.", set_trampoline_routing_optional, set_trampoline_routing_required,
- supports_trampoline_routing, requires_trampoline_routing);
- // Note: update the module-level docs when a new feature bit is added!
-
- #[cfg(test)]
- define_feature!(123456789, UnknownFeature,
- [NodeContext, ChannelContext, Bolt11InvoiceContext, OfferContext, InvoiceRequestContext, Bolt12InvoiceContext, BlindedHopContext],
- "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
- 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.
-///
-/// This is not exported to bindings users as we map the concrete feature types below directly instead
-#[derive(Eq)]
-pub struct Features<T: sealed::Context> {
- /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
- flags: Vec<u8>,
- 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 {
- self |= o;
- self
- }
-}
-
-impl<T: sealed::Context> Clone for Features<T> {
- fn clone(&self) -> Self {
- Self {
- flags: self.flags.clone(),
- mark: PhantomData,
- }
- }
-}
-impl<T: sealed::Context> Hash for Features<T> {
- fn hash<H: Hasher>(&self, hasher: &mut H) {
- let mut nonzero_flags = &self.flags[..];
- while nonzero_flags.last() == Some(&0) {
- nonzero_flags = &nonzero_flags[..nonzero_flags.len() - 1];
- }
- nonzero_flags.hash(hasher);
- }
-}
-impl<T: sealed::Context> PartialEq for Features<T> {
- fn eq(&self, o: &Self) -> bool {
- let mut o_iter = o.flags.iter();
- let mut self_iter = self.flags.iter();
- loop {
- match (o_iter.next(), self_iter.next()) {
- (Some(o), Some(us)) => if o != us { return false },
- (Some(b), None) | (None, Some(b)) => if *b != 0 { return false },
- (None, None) => return true,
- }
- }
- }
-}
-impl<T: sealed::Context> PartialOrd for Features<T> {
- fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
- self.flags.partial_cmp(&other.flags)
- }
-}
-impl<T: sealed::Context + Eq> Ord for Features<T> {
- fn cmp(&self, other: &Self) -> cmp::Ordering {
- self.flags.cmp(&other.flags)
- }
-}
-impl<T: sealed::Context> fmt::Debug for Features<T> {
- fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
- self.flags.fmt(fmt)
- }
-}
-
-/// Features used within an `init` message.
-pub type InitFeatures = Features<sealed::InitContext>;
-/// Features used within a `node_announcement` message.
-pub type NodeFeatures = Features<sealed::NodeContext>;
-/// Features used within a `channel_announcement` message.
-pub type ChannelFeatures = Features<sealed::ChannelContext>;
-/// Features used within an invoice.
-pub type Bolt11InvoiceFeatures = Features<sealed::Bolt11InvoiceContext>;
-/// Features used within an `offer`.
-pub type OfferFeatures = Features<sealed::OfferContext>;
-/// Features used within an `invoice_request`.
-pub type InvoiceRequestFeatures = Features<sealed::InvoiceRequestContext>;
-/// Features used within an `invoice`.
-pub type Bolt12InvoiceFeatures = Features<sealed::Bolt12InvoiceContext>;
-/// Features used within BOLT 4 encrypted_data_tlv and BOLT 12 blinded_payinfo
-pub type BlindedHopFeatures = Features<sealed::BlindedHopContext>;
-
-/// 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> {
- let len = cmp::min(2, self.flags.len());
- (len as u16).write(w)?;
- for i in (0..len).rev() {
- if i == 0 {
- self.flags[i].write(w)?;
- } else {
- // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
- // up-to-and-including-bit-5, 0-indexed, on this byte:
- (self.flags[i] & 0b00_11_11_11).write(w)?;
- }
- }
- Ok(())
- }
-
- /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
- /// are included in the result.
- pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
- self.to_context_internal()
- }
-}
-
-impl Bolt11InvoiceFeatures {
- /// Converts `Bolt11InvoiceFeatures` to `Features<C>`. Only known `Bolt11InvoiceFeatures` relevant to
- /// context `C` are included in the result.
- 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
- /// [`PaymentParameters::for_keysend`], thus omitting the need for payers to manually construct an
- /// `Bolt11InvoiceFeatures` for [`find_route`].
- ///
- /// MPP keysend is not widely supported yet, so we parameterize support to allow the user to
- /// choose whether their router should find multi-part routes.
- ///
- /// [`PaymentParameters::for_keysend`]: crate::routing::router::PaymentParameters::for_keysend
- /// [`find_route`]: crate::routing::router::find_route
- pub(crate) fn for_keysend(allow_mpp: bool) -> Bolt11InvoiceFeatures {
- let mut res = Bolt11InvoiceFeatures::empty();
- res.set_variable_length_onion_optional();
- if allow_mpp {
- res.set_basic_mpp_optional();
- }
- res
- }
-}
-
-impl Bolt12InvoiceFeatures {
- /// Converts [`Bolt12InvoiceFeatures`] to [`Features<C>`]. Only known [`Bolt12InvoiceFeatures`]
- /// relevant to context `C` are included in the result.
- pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
- self.to_context_internal()
- }
-}
-
-impl ChannelTypeFeatures {
- // Maps the relevant `InitFeatures` to `ChannelTypeFeatures`. Any unknown features to
- // `ChannelTypeFeatures` are not included in the result.
- pub(crate) fn from_init(init: &InitFeatures) -> Self {
- let mut ret = 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 & ANY_OPTIONAL_FEATURES_MASK) >> 1;
- *byte &= ANY_REQUIRED_FEATURES_MASK;
- }
- 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
- }
-
- /// 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 Bolt11InvoiceFeatures {
- 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
- // minus one before dividing
- let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
- let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
- for (byte_idx, byte) in self.flags.iter().enumerate() {
- let bit_pos_from_left_0_indexed = byte_idx * 8;
- let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
- let new_bit_pos = bit_pos_from_left_0_indexed % 5;
- let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
- let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
- res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
- if new_u5_idx > 0 {
- let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
- res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
- }
- if new_u5_idx > 1 {
- let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
- res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
- }
- }
- // Trim the highest feature bits.
- while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
- res_u5s.remove(0);
- }
- writer.write(&res_u5s)
- }
-}
-
-impl Base32Len for Bolt11InvoiceFeatures {
- fn base32_len(&self) -> usize {
- self.to_base32().len()
- }
-}
-
-impl FromBase32 for Bolt11InvoiceFeatures {
- type Err = bech32::Error;
-
- fn from_base32(field_data: &[u5]) -> Result<Bolt11InvoiceFeatures, bech32::Error> {
- // Explanation for the "7": the normal way to round up when dividing is to add the divisor
- // minus one before dividing
- let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
- let mut res_bytes: Vec<u8> = vec![0; length_bytes];
- for (u5_idx, chunk) in field_data.iter().enumerate() {
- let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
- let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
- let new_bit_pos = bit_pos_from_right_0_indexed % 8;
- let chunk_u16 = chunk.to_u8() as u16;
- res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
- if new_byte_idx != length_bytes - 1 {
- res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
- }
- }
- // Trim the highest feature bits.
- while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
- res_bytes.pop();
- }
- Ok(Bolt11InvoiceFeatures::from_le_bytes(res_bytes))
- }
-}
-
-impl<T: sealed::Context> Features<T> {
- /// Create a blank Features with no features set
- pub fn empty() -> Self {
- Features {
- flags: Vec::new(),
- mark: PhantomData,
- }
- }
-
- /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
- /// included in the result.
- fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
- let from_byte_count = T::KNOWN_FEATURE_MASK.len();
- let to_byte_count = C::KNOWN_FEATURE_MASK.len();
- let mut flags = Vec::new();
- for (i, byte) in self.flags.iter().enumerate() {
- if i < from_byte_count && i < to_byte_count {
- let from_known_features = T::KNOWN_FEATURE_MASK[i];
- let to_known_features = C::KNOWN_FEATURE_MASK[i];
- flags.push(byte & from_known_features & to_known_features);
- }
- }
- Features::<C> { flags, mark: PhantomData, }
- }
-
- /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
- /// most on-the-wire encodings.
- ///
- /// This is not exported to bindings users as we don't support export across multiple T
- pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
- Features {
- flags,
- mark: PhantomData,
- }
- }
-
- #[cfg(test)]
- /// Gets the underlying flags set, in LE.
- pub fn le_flags(&self) -> &Vec<u8> {
- &self.flags
- }
+use crate::util::ser::{Writer, Readable, Writeable, WithoutLength};
- 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(())
- }
-
- /// Create a [`Features`] given a set of flags, in big-endian. This is in byte order from
- /// most on-the-wire encodings.
- ///
- /// This is not exported to bindings users as we don't support export across multiple T
- pub 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 & ANY_OPTIONAL_FEATURES_MASK) != 0)
- }
-
- /// Returns true if this `Features` object contains required features unknown by `other`.
- pub fn requires_unknown_bits_from(&self, other: &Self) -> bool {
- // Bitwise AND-ing with all even bits set except for known features will select required
- // unknown features.
- self.flags.iter().enumerate().any(|(i, &byte)| {
- let unknown_features = unset_features_mask_at_position(other, i);
- (byte & (ANY_REQUIRED_FEATURES_MASK & unknown_features)) != 0
- })
- }
-
- pub(crate) fn required_unknown_bits_from(&self, other: &Self) -> Vec<usize> {
- let mut unknown_bits = Vec::new();
-
- // 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)| {
- 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 {
- unknown_bits.push(i * 8 + bit);
- }
- }
- }
- });
-
- unknown_bits
- }
-
- /// 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 mut known_chunks = T::KNOWN_FEATURE_MASK.chunks(8);
- for chunk in self.flags.chunks(8) {
- let mut flag_bytes = [0; 8];
- flag_bytes[..chunk.len()].copy_from_slice(&chunk);
- let flag_int = u64::from_le_bytes(flag_bytes);
-
- let known_chunk = known_chunks.next().unwrap_or(&[0; 0]);
- let mut known_bytes = [0; 8];
- known_bytes[..known_chunk.len()].copy_from_slice(&known_chunk);
- let known_int = u64::from_le_bytes(known_bytes);
-
- const REQ_MASK: u64 = u64::from_le_bytes([ANY_REQUIRED_FEATURES_MASK; 8]);
- if flag_int & (REQ_MASK & !known_int) != 0 {
- return true;
- }
- }
- false
- }
-
- pub(crate) fn supports_unknown_bits(&self) -> bool {
- // Bitwise AND-ing with all even and odd bits set except for known features will select
- // both required and optional unknown features.
- let byte_count = T::KNOWN_FEATURE_MASK.len();
- self.flags.iter().enumerate().any(|(i, &byte)| {
- let unknown_features = if i < byte_count {
- !T::KNOWN_FEATURE_MASK[i]
- } else {
- 0b11_11_11_11
- };
- (byte & unknown_features) != 0
- })
- }
-
- /// Sets a required feature bit. Errors if `bit` is outside the feature range as defined
- /// by [BOLT 9].
- ///
- /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
- /// be set instead (i.e., `bit - 1`).
- ///
- /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
- pub fn set_required_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
- self.set_feature_bit(bit - (bit % 2))
- }
-
- /// Sets an optional feature bit. Errors if `bit` is outside the feature range as defined
- /// by [BOLT 9].
- ///
- /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
- /// set instead (i.e., `bit + 1`).
- ///
- /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
- pub fn set_optional_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
- self.set_feature_bit(bit + (1 - (bit % 2)))
- }
-
- fn set_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
- if bit > 255 {
- return Err(());
- }
- self.set_bit(bit, false)
- }
-
- /// Sets a required custom feature bit. Errors if `bit` is outside the custom range as defined
- /// by [bLIP 2] or if it is a known `T` feature.
- ///
- /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
- /// be set instead (i.e., `bit - 1`).
- ///
- /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
- pub fn set_required_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
- self.set_custom_bit(bit - (bit % 2))
- }
-
- /// Sets an optional custom feature bit. Errors if `bit` is outside the custom range as defined
- /// by [bLIP 2] or if it is a known `T` feature.
- ///
- /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
- /// set instead (i.e., `bit + 1`).
- ///
- /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
- pub fn set_optional_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
- self.set_custom_bit(bit + (1 - (bit % 2)))
- }
-
- fn set_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
- if bit < 256 {
- return Err(());
- }
- self.set_bit(bit, true)
- }
-
- fn set_bit(&mut self, bit: usize, custom: bool) -> Result<(), ()> {
- let byte_offset = bit / 8;
- let mask = 1 << (bit - 8 * byte_offset);
- if byte_offset < T::KNOWN_FEATURE_MASK.len() && custom {
- if (T::KNOWN_FEATURE_MASK[byte_offset] & mask) != 0 {
- return Err(());
- }
- }
-
- if self.flags.len() <= byte_offset {
- self.flags.resize(byte_offset + 1, 0u8);
- }
-
- self.flags[byte_offset] |= mask;
-
- Ok(())
- }
-}
-
-impl<T: sealed::UpfrontShutdownScript> Features<T> {
- #[cfg(test)]
- pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
- <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
- self
- }
-}
-
-impl<T: sealed::ShutdownAnySegwit> Features<T> {
- #[cfg(test)]
- pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
- <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
- self
- }
-}
-
-impl<T: sealed::Wumbo> Features<T> {
- #[cfg(test)]
- pub(crate) fn clear_wumbo(mut self) -> Self {
- <T as sealed::Wumbo>::clear_bits(&mut self.flags);
- self
- }
-}
-
-impl<T: sealed::SCIDPrivacy> Features<T> {
- pub(crate) fn clear_scid_privacy(&mut self) {
- <T as sealed::SCIDPrivacy>::clear_bits(&mut self.flags);
- }
-}
-
-impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
- pub(crate) fn clear_anchors_zero_fee_htlc_tx(&mut self) {
- <T as sealed::AnchorsZeroFeeHtlcTx>::clear_bits(&mut self.flags);
- }
-}
-
-impl<T: sealed::RouteBlinding> Features<T> {
- #[cfg(test)]
- pub(crate) fn clear_route_blinding(&mut self) {
- <T as sealed::RouteBlinding>::clear_bits(&mut self.flags);
- }
-}
-
-#[cfg(test)]
-impl<T: sealed::UnknownFeature> Features<T> {
- pub(crate) fn unknown() -> Self {
- let mut features = Self::empty();
- features.set_unknown_feature_required();
- features
+fn write_be<W: Writer>(w: &mut W, le_flags: &[u8]) -> Result<(), io::Error> {
+ for f in le_flags.iter().rev() { // Swap back to big-endian
+ f.write(w)?;
}
+ Ok(())
}
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)
+ let bytes = self.le_flags();
+ (bytes.len() as u16).write(w)?;
+ write_be(w, bytes)
}
}
impl Readable for $features {
// Some features may appear both in a TLV record and as part of a TLV subtype sequence. The latter
// requires a length but the former does not.
-impl<T: sealed::Context> Writeable for WithoutLength<&Features<T>> {
- fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
- self.0.write_be(w)
- }
-}
+macro_rules! impl_feature_write_without_length {
+ ($features: ident) => {
+ impl Writeable for WithoutLength<&$features> {
+ fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ write_be(w, self.0.le_flags())
+ }
+ }
-impl<T: sealed::Context> Readable for WithoutLength<Features<T>> {
- fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
- let v = io_extras::read_to_end(r)?;
- Ok(WithoutLength(Features::<T>::from_be_bytes(v)))
+ impl Readable for WithoutLength<$features> {
+ fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ let v = io_extras::read_to_end(r)?;
+ Ok(WithoutLength($features::from_be_bytes(v)))
+ }
+ }
}
}
-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
- }
-}
+impl_feature_write_without_length!(Bolt12InvoiceFeatures);
+impl_feature_write_without_length!(ChannelTypeFeatures);
+impl_feature_write_without_length!(InvoiceRequestFeatures);
+impl_feature_write_without_length!(OfferFeatures);
#[cfg(test)]
mod tests {
- use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, Bolt11InvoiceFeatures, NodeFeatures, OfferFeatures, sealed};
- use bech32::{Base32Len, FromBase32, ToBase32, u5};
+ use super::*;
use crate::util::ser::{Readable, WithoutLength, Writeable};
- #[test]
- fn sanity_test_unknown_bits() {
- let features = ChannelFeatures::empty();
- assert!(!features.requires_unknown_bits());
- assert!(!features.supports_unknown_bits());
-
- let mut features = ChannelFeatures::empty();
- features.set_unknown_feature_required();
- assert!(features.requires_unknown_bits());
- assert!(features.supports_unknown_bits());
- assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456788]);
-
- let mut features = ChannelFeatures::empty();
- features.set_unknown_feature_optional();
- assert!(!features.requires_unknown_bits());
- assert!(features.supports_unknown_bits());
- assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![]);
-
- let mut features = ChannelFeatures::empty();
- features.set_unknown_feature_required();
- features.set_custom_bit(123456786).unwrap();
- assert!(features.requires_unknown_bits());
- assert!(features.supports_unknown_bits());
- assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456786, 123456788]);
-
- let mut limiter = ChannelFeatures::empty();
- limiter.set_unknown_feature_optional();
- assert_eq!(features.required_unknown_bits_from(&limiter), vec![123456786]);
- }
-
- #[test]
- fn requires_unknown_bits_from() {
- let mut features1 = InitFeatures::empty();
- let mut features2 = InitFeatures::empty();
- assert!(!features1.requires_unknown_bits_from(&features2));
- assert!(!features2.requires_unknown_bits_from(&features1));
-
- features1.set_data_loss_protect_required();
- assert!(features1.requires_unknown_bits_from(&features2));
- assert!(!features2.requires_unknown_bits_from(&features1));
-
- features2.set_data_loss_protect_optional();
- assert!(!features1.requires_unknown_bits_from(&features2));
- assert!(!features2.requires_unknown_bits_from(&features1));
-
- features2.set_gossip_queries_required();
- assert!(!features1.requires_unknown_bits_from(&features2));
- assert!(features2.requires_unknown_bits_from(&features1));
-
- features1.set_gossip_queries_optional();
- assert!(!features1.requires_unknown_bits_from(&features2));
- assert!(!features2.requires_unknown_bits_from(&features1));
-
- features1.set_variable_length_onion_required();
- assert!(features1.requires_unknown_bits_from(&features2));
- assert!(!features2.requires_unknown_bits_from(&features1));
-
- features2.set_variable_length_onion_optional();
- assert!(!features1.requires_unknown_bits_from(&features2));
- assert!(!features2.requires_unknown_bits_from(&features1));
-
- features1.set_basic_mpp_required();
- features2.set_wumbo_required();
- assert!(features1.requires_unknown_bits_from(&features2));
- assert!(features2.requires_unknown_bits_from(&features1));
- }
-
- #[test]
- fn convert_to_context_with_relevant_flags() {
- let mut init_features = InitFeatures::empty();
- // Set a bunch of features we use, plus initial_routing_sync_required (which shouldn't get
- // converted as it's only relevant in an init context).
- init_features.set_initial_routing_sync_required();
- init_features.set_data_loss_protect_required();
- init_features.set_variable_length_onion_required();
- init_features.set_static_remote_key_required();
- init_features.set_payment_secret_required();
- init_features.set_basic_mpp_optional();
- init_features.set_wumbo_optional();
- init_features.set_anchors_zero_fee_htlc_tx_optional();
- init_features.set_route_blinding_optional();
- init_features.set_shutdown_any_segwit_optional();
- init_features.set_onion_messages_optional();
- init_features.set_channel_type_optional();
- init_features.set_scid_privacy_optional();
- init_features.set_zero_conf_optional();
-
- assert!(init_features.initial_routing_sync());
- assert!(!init_features.supports_upfront_shutdown_script());
- assert!(!init_features.supports_gossip_queries());
-
- let node_features: NodeFeatures = init_features.to_context();
- {
- // Check that the flags are as expected:
- // - option_data_loss_protect (req)
- // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
- // - basic_mpp | wumbo | option_anchors_zero_fee_htlc_tx
- // - option_route_blinding | opt_shutdown_anysegwit
- // - onion_messages
- // - option_channel_type | option_scid_alias
- // - option_zeroconf
- assert_eq!(node_features.flags.len(), 7);
- assert_eq!(node_features.flags[0], 0b00000001);
- assert_eq!(node_features.flags[1], 0b01010001);
- assert_eq!(node_features.flags[2], 0b10001010);
- assert_eq!(node_features.flags[3], 0b00001010);
- assert_eq!(node_features.flags[4], 0b10000000);
- assert_eq!(node_features.flags[5], 0b10100000);
- assert_eq!(node_features.flags[6], 0b00001000);
- }
-
- // Check that cleared flags are kept blank when converting back:
- // - initial_routing_sync was not applicable to NodeContext
- // - upfront_shutdown_script was cleared before converting
- // - gossip_queries was cleared before converting
- let features: InitFeatures = node_features.to_context_internal();
- assert!(!features.initial_routing_sync());
- assert!(!features.supports_upfront_shutdown_script());
- assert!(!init_features.supports_gossip_queries());
- }
-
- #[test]
- fn convert_to_context_with_unknown_flags() {
- // Ensure the `from` context has fewer known feature bytes than the `to` context.
- assert!(<sealed::ChannelContext as sealed::Context>::KNOWN_FEATURE_MASK.len() <
- <sealed::Bolt11InvoiceContext as sealed::Context>::KNOWN_FEATURE_MASK.len());
- let mut channel_features = ChannelFeatures::empty();
- channel_features.set_unknown_feature_optional();
- assert!(channel_features.supports_unknown_bits());
- let invoice_features: Bolt11InvoiceFeatures = channel_features.to_context_internal();
- assert!(!invoice_features.supports_unknown_bits());
- }
-
- #[test]
- fn set_feature_bits() {
- let mut features = Bolt11InvoiceFeatures::empty();
- features.set_basic_mpp_optional();
- features.set_payment_secret_required();
- assert!(features.supports_basic_mpp());
- assert!(!features.requires_basic_mpp());
- assert!(features.requires_payment_secret());
- assert!(features.supports_payment_secret());
-
- // Set flags manually
- let mut features = NodeFeatures::empty();
- assert!(features.set_optional_feature_bit(55).is_ok());
- assert!(features.supports_keysend());
- assert!(features.set_optional_feature_bit(255).is_ok());
- assert!(features.set_required_feature_bit(256).is_err());
- }
-
- #[test]
- fn set_custom_bits() {
- let mut features = Bolt11InvoiceFeatures::empty();
- features.set_variable_length_onion_optional();
- assert_eq!(features.flags[1], 0b00000010);
-
- assert!(features.set_optional_custom_bit(255).is_err());
- assert!(features.set_required_custom_bit(256).is_ok());
- assert!(features.set_required_custom_bit(258).is_ok());
- assert_eq!(features.flags[31], 0b00000000);
- assert_eq!(features.flags[32], 0b00000101);
-
- let known_bit = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::EVEN_BIT;
- let byte_offset = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::BYTE_OFFSET;
- assert_eq!(byte_offset, 1);
- assert_eq!(features.flags[byte_offset], 0b00000010);
- assert!(features.set_required_custom_bit(known_bit).is_err());
- assert_eq!(features.flags[byte_offset], 0b00000010);
-
- let mut features = Bolt11InvoiceFeatures::empty();
- assert!(features.set_optional_custom_bit(256).is_ok());
- assert!(features.set_optional_custom_bit(259).is_ok());
- assert_eq!(features.flags[32], 0b00001010);
-
- let mut features = Bolt11InvoiceFeatures::empty();
- assert!(features.set_required_custom_bit(257).is_ok());
- assert!(features.set_required_custom_bit(258).is_ok());
- assert_eq!(features.flags[32], 0b00000101);
- }
-
#[test]
fn encodes_features_without_length() {
let features = OfferFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
- assert_eq!(features.flags.len(), 8);
+ assert_eq!(features.le_flags().len(), 8);
let mut serialized_features = Vec::new();
WithoutLength(&features).write(&mut serialized_features).unwrap();
WithoutLength::<OfferFeatures>::read(&mut &serialized_features[..]).unwrap().0;
assert_eq!(features, deserialized_features);
}
-
- #[test]
- fn invoice_features_encoding() {
- let features_as_u5s = vec![
- u5::try_from_u8(6).unwrap(),
- u5::try_from_u8(10).unwrap(),
- u5::try_from_u8(25).unwrap(),
- u5::try_from_u8(1).unwrap(),
- u5::try_from_u8(10).unwrap(),
- u5::try_from_u8(0).unwrap(),
- u5::try_from_u8(20).unwrap(),
- u5::try_from_u8(2).unwrap(),
- u5::try_from_u8(0).unwrap(),
- u5::try_from_u8(6).unwrap(),
- u5::try_from_u8(0).unwrap(),
- u5::try_from_u8(16).unwrap(),
- u5::try_from_u8(1).unwrap(),
- ];
- let features = Bolt11InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
-
- // Test length calculation.
- assert_eq!(features.base32_len(), 13);
-
- // Test serialization.
- let features_serialized = features.to_base32();
- assert_eq!(features_as_u5s, features_serialized);
-
- // Test deserialization.
- let features_deserialized = Bolt11InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
- assert_eq!(features, features_deserialized);
- }
-
- #[test]
- fn test_channel_type_mapping() {
- // If we map an Bolt11InvoiceFeatures with StaticRemoteKey optional, it should map into a
- // required-StaticRemoteKey ChannelTypeFeatures.
- let mut init_features = InitFeatures::empty();
- init_features.set_static_remote_key_optional();
- let converted_features = ChannelTypeFeatures::from_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());
- }
-
- #[test]
- #[cfg(feature = "std")]
- fn test_excess_zero_bytes_ignored() {
- // Checks that `Hash` and `PartialEq` ignore excess zero bytes, which may appear due to
- // feature conversion or because a peer serialized their feature poorly.
- use std::collections::hash_map::DefaultHasher;
- use std::hash::{Hash, Hasher};
-
- let mut zerod_features = InitFeatures::empty();
- zerod_features.flags = vec![0];
- let empty_features = InitFeatures::empty();
- assert!(empty_features.flags.is_empty());
-
- assert_eq!(zerod_features, empty_features);
-
- let mut zerod_hash = DefaultHasher::new();
- zerod_features.hash(&mut zerod_hash);
- let mut empty_hash = DefaultHasher::new();
- empty_features.hash(&mut empty_hash);
- assert_eq!(zerod_hash.finish(), empty_hash.finish());
- }
}
projects / rust-lightning / commitdiff