X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=259bda85eee7925f8f455058803fa850b3f29259;hb=871f4143672b9d8e616dbc2b6df87366590179d0;hp=0dd5fa3049364a853c99ce34fe69d226a8dab689;hpb=65ff1bf0beaeb33397c5024d278a65a780fc8ffd;p=rust-lightning diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs index 0dd5fa30..259bda85 100644 --- a/lightning/src/ln/features.rs +++ b/lightning/src/ln/features.rs @@ -1,10 +1,18 @@ +// This file is Copyright its original authors, visible in version control +// history. +// +// This file is licensed under the Apache License, Version 2.0 or the MIT license +// , 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 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). A -//! [`Context`] is used to parameterize [`Features`] and defines which features it can support. +//! 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 @@ -12,22 +20,19 @@ //! And the implementation can interpret a feature if the feature is known to it. //! //! [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md -//! [messages]: ../msgs/index.html -//! [`Features`]: struct.Features.html -//! [`Context`]: sealed/trait.Context.html +//! [messages]: crate::ln::msgs use std::{cmp, fmt}; -use std::result::Result; use std::marker::PhantomData; use ln::msgs::DecodeError; use util::ser::{Readable, Writeable, Writer}; mod sealed { + use ln::features::Features; + /// The context in which [`Features`] are applicable. Defines which features are required and /// which are optional for the context. - /// - /// [`Features`]: ../struct.Features.html pub trait Context { /// Features that are known to the implementation, where a required feature is indicated by /// its even bit and an optional feature is indicated by its odd bit. @@ -41,8 +46,6 @@ mod sealed { /// 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. - /// - /// [`Context`]: trait.Context.html macro_rules! define_context { ($context: ident { required_features: [$( $( $required_feature: ident )|*, )*], @@ -89,17 +92,21 @@ mod sealed { // Byte 0 , // Byte 1 - , + StaticRemoteKey, // Byte 2 , + // Byte 3 + , ], optional_features: [ // Byte 0 - DataLossProtect | InitialRoutingSync | UpfrontShutdownScript, + DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries, // Byte 1 VariableLengthOnion | PaymentSecret, // Byte 2 BasicMPP, + // Byte 3 + ShutdownAnySegwit, ], }); define_context!(NodeContext { @@ -107,30 +114,44 @@ mod sealed { // Byte 0 , // Byte 1 - , + StaticRemoteKey, // Byte 2 , + // Byte 3 + , ], optional_features: [ // Byte 0 - DataLossProtect | UpfrontShutdownScript, + DataLossProtect | UpfrontShutdownScript | GossipQueries, // Byte 1 VariableLengthOnion | PaymentSecret, // Byte 2 BasicMPP, + // Byte 3 + ShutdownAnySegwit, ], }); define_context!(ChannelContext { required_features: [], optional_features: [], }); + define_context!(InvoiceContext { + required_features: [,,,], + optional_features: [ + // Byte 0 + , + // Byte 1 + VariableLengthOnion | PaymentSecret, + // Byte 2 + BasicMPP, + ], + }); /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is /// useful for manipulating feature flags. - /// - /// [`Context`]: trait.Context.html macro_rules! define_feature { - ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr) => { + ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident, + $required_setter: ident) => { #[doc = $doc] /// /// See [BOLT #9] for details. @@ -166,6 +187,13 @@ mod sealed { /// [`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) -> 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) -> bool { @@ -173,6 +201,16 @@ mod sealed { (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) { + if flags.len() <= Self::BYTE_OFFSET { + flags.resize(Self::BYTE_OFFSET + 1, 0u8); + } + + flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK; + } + /// Sets the feature's optional (odd) bit in the given flags. #[inline] fn set_optional_bit(flags: &mut Vec) { @@ -191,6 +229,24 @@ mod sealed { 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 Features { + /// Set this feature as optional. + pub fn $optional_setter(mut self) -> Self { + ::set_optional_bit(&mut self.flags); + self + } + + /// Set this feature as required. + pub fn $required_setter(mut self) -> Self { + ::set_required_bit(&mut self.flags); + self } } @@ -203,26 +259,65 @@ mod sealed { const ASSERT_ODD_BIT_PARITY: usize = (::ODD_BIT % 2) - 1; } )* + } } define_feature!(1, DataLossProtect, [InitContext, NodeContext], - "Feature flags for `option_data_loss_protect`."); + "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional, + set_data_loss_protect_required); // NOTE: Per Bolt #9, initial_routing_sync has no even bit. - define_feature!(3, InitialRoutingSync, [InitContext], - "Feature flags for `initial_routing_sync`."); + define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.", + set_initial_routing_sync_optional, set_initial_routing_sync_required); define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext], - "Feature flags for `option_upfront_shutdown_script`."); - define_feature!(9, VariableLengthOnion, [InitContext, NodeContext], - "Feature flags for `var_onion_optin`."); - define_feature!(15, PaymentSecret, [InitContext, NodeContext], - "Feature flags for `payment_secret`."); - define_feature!(17, BasicMPP, [InitContext, NodeContext], - "Feature flags for `basic_mpp`."); + "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional, + set_upfront_shutdown_script_required); + define_feature!(7, GossipQueries, [InitContext, NodeContext], + "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required); + define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext], + "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional, + set_variable_length_onion_required); + define_feature!(13, StaticRemoteKey, [InitContext, NodeContext], + "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional, + set_static_remote_key_required); + define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext], + "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required); + define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext], + "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required); + define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext], + "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional, + set_shutdown_any_segwit_required); + + #[cfg(test)] + define_context!(TestingContext { + required_features: [ + // Byte 0 + , + // Byte 1 + , + // Byte 2 + UnknownFeature, + ], + optional_features: [ + // Byte 0 + , + // Byte 1 + , + // Byte 2 + , + ], + }); + + #[cfg(test)] + define_feature!(23, UnknownFeature, [TestingContext], + "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional, + set_unknown_feature_required); } /// Tracks the set of features which a node implements, templated by the context in which it /// appears. +/// +/// (C-not exported) as we map the concrete feature types below directly instead pub struct Features { /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire) flags: Vec, @@ -254,6 +349,8 @@ pub type InitFeatures = Features; pub type NodeFeatures = Features; /// Features used within a `channel_announcement` message. pub type ChannelFeatures = Features; +/// Features used within an invoice. +pub type InvoiceFeatures = Features; impl InitFeatures { /// Writes all features present up to, and including, 13. @@ -282,39 +379,52 @@ impl InitFeatures { } self } + + /// Converts `InitFeatures` to `Features`. Only known `InitFeatures` relevant to context `C` + /// are included in the result. + pub(crate) fn to_context(&self) -> Features { + self.to_context_internal() + } +} + +impl InvoiceFeatures { + /// Converts `InvoiceFeatures` to `Features`. Only known `InvoiceFeatures` relevant to + /// context `C` are included in the result. + pub(crate) fn to_context(&self) -> Features { + self.to_context_internal() + } } impl Features { /// Create a blank Features with no features set - pub fn empty() -> Features { + pub fn empty() -> Self { Features { flags: Vec::new(), mark: PhantomData, } } - /// Creates features known by the implementation as defined by [`T::KNOWN_FEATURE_FLAGS`]. - /// - /// [`T::KNOWN_FEATURE_FLAGS`]: sealed/trait.Context.html#associatedconstant.KNOWN_FEATURE_FLAGS - pub fn known() -> Features { + /// Creates a Features with the bits set which are known by the implementation + pub fn known() -> Self { Self { flags: T::KNOWN_FEATURE_FLAGS.to_vec(), mark: PhantomData, } } - /// Takes the flags that we know how to interpret in an init-context features that are also - /// relevant in a node-context features and creates a node-context features from them. - /// Be sure to blank out features that are unknown to us. - pub(crate) fn with_known_relevant_init_flags(init_ctx: &InitFeatures) -> Self { - let byte_count = T::KNOWN_FEATURE_MASK.len(); + /// Converts `Features` to `Features`. Only known `T` features relevant to context `C` are + /// included in the result. + fn to_context_internal(&self) -> Features { + let byte_count = C::KNOWN_FEATURE_MASK.len(); let mut flags = Vec::new(); - for (i, feature_byte) in init_ctx.flags.iter().enumerate() { + for (i, byte) in self.flags.iter().enumerate() { if i < byte_count { - flags.push(feature_byte & T::KNOWN_FEATURE_MASK[i]); + let known_source_features = T::KNOWN_FEATURE_MASK[i]; + let known_target_features = C::KNOWN_FEATURE_MASK[i]; + flags.push(byte & known_source_features & known_target_features); } } - Self { flags, mark: PhantomData, } + Features:: { flags, mark: PhantomData, } } #[cfg(test)] @@ -368,75 +478,131 @@ impl Features { } #[cfg(test)] - pub(crate) fn set_require_unknown_bits(&mut self) { - let newlen = cmp::max(3, self.flags.len()); - self.flags.resize(newlen, 0u8); - self.flags[2] |= 0x40; + pub(crate) fn set_required_unknown_bits(&mut self) { + ::set_required_bit(&mut self.flags); } #[cfg(test)] - pub(crate) fn clear_require_unknown_bits(&mut self) { - let newlen = cmp::max(3, self.flags.len()); - self.flags.resize(newlen, 0u8); - self.flags[2] &= !0x40; - if self.flags.len() == 3 && self.flags[2] == 0 { - self.flags.resize(2, 0u8); - } - if self.flags.len() == 2 && self.flags[1] == 0 { - self.flags.resize(1, 0u8); - } + pub(crate) fn set_optional_unknown_bits(&mut self) { + ::set_optional_bit(&mut self.flags); + } + + #[cfg(test)] + pub(crate) fn clear_unknown_bits(&mut self) { + ::clear_bits(&mut self.flags); } } impl Features { + #[cfg(test)] + pub(crate) fn requires_data_loss_protect(&self) -> bool { + ::requires_feature(&self.flags) + } pub(crate) fn supports_data_loss_protect(&self) -> bool { ::supports_feature(&self.flags) } } impl Features { + #[cfg(test)] + pub(crate) fn requires_upfront_shutdown_script(&self) -> bool { + ::requires_feature(&self.flags) + } pub(crate) fn supports_upfront_shutdown_script(&self) -> bool { ::supports_feature(&self.flags) } #[cfg(test)] - pub(crate) fn unset_upfront_shutdown_script(&mut self) { - ::clear_bits(&mut self.flags) + pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self { + ::clear_bits(&mut self.flags); + self + } +} + + +impl Features { + #[cfg(test)] + pub(crate) fn requires_gossip_queries(&self) -> bool { + ::requires_feature(&self.flags) + } + pub(crate) fn supports_gossip_queries(&self) -> bool { + ::supports_feature(&self.flags) + } + #[cfg(test)] + pub(crate) fn clear_gossip_queries(mut self) -> Self { + ::clear_bits(&mut self.flags); + self } } impl Features { + #[cfg(test)] + pub(crate) fn requires_variable_length_onion(&self) -> bool { + ::requires_feature(&self.flags) + } pub(crate) fn supports_variable_length_onion(&self) -> bool { ::supports_feature(&self.flags) } } +impl Features { + pub(crate) fn supports_static_remote_key(&self) -> bool { + ::supports_feature(&self.flags) + } + #[cfg(test)] + pub(crate) fn requires_static_remote_key(&self) -> bool { + ::requires_feature(&self.flags) + } +} + impl Features { pub(crate) fn initial_routing_sync(&self) -> bool { ::supports_feature(&self.flags) } + // We are no longer setting initial_routing_sync now that gossip_queries + // is enabled. This feature is ignored by a peer when gossip_queries has + // been negotiated. + #[cfg(test)] pub(crate) fn clear_initial_routing_sync(&mut self) { ::clear_bits(&mut self.flags) } } impl Features { - #[allow(dead_code)] + #[cfg(test)] + pub(crate) fn requires_payment_secret(&self) -> bool { + ::requires_feature(&self.flags) + } // Note that we never need to test this since what really matters is the invoice - iff the // invoice provides a payment_secret, we assume that we can use it (ie that the recipient // supports payment_secret). + #[allow(dead_code)] pub(crate) fn supports_payment_secret(&self) -> bool { ::supports_feature(&self.flags) } } impl Features { + #[cfg(test)] + pub(crate) fn requires_basic_mpp(&self) -> bool { + ::requires_feature(&self.flags) + } // We currently never test for this since we don't actually *generate* multipath routes. - #[allow(dead_code)] pub(crate) fn supports_basic_mpp(&self) -> bool { ::supports_feature(&self.flags) } } +impl Features { + pub(crate) fn supports_shutdown_anysegwit(&self) -> bool { + ::supports_feature(&self.flags) + } + #[cfg(test)] + pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self { + ::clear_bits(&mut self.flags); + self + } +} + impl Writeable for Features { fn write(&self, w: &mut W) -> Result<(), ::std::io::Error> { w.size_hint(self.flags.len() + 2); @@ -461,10 +627,10 @@ impl Readable for Features { #[cfg(test)] mod tests { - use super::{ChannelFeatures, InitFeatures, NodeFeatures, Features}; + use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures}; #[test] - fn sanity_test_our_features() { + fn sanity_test_known_features() { assert!(!ChannelFeatures::known().requires_unknown_bits()); assert!(!ChannelFeatures::known().supports_unknown_bits()); assert!(!InitFeatures::known().requires_unknown_bits()); @@ -474,18 +640,41 @@ mod tests { assert!(InitFeatures::known().supports_upfront_shutdown_script()); assert!(NodeFeatures::known().supports_upfront_shutdown_script()); + assert!(!InitFeatures::known().requires_upfront_shutdown_script()); + assert!(!NodeFeatures::known().requires_upfront_shutdown_script()); + + assert!(InitFeatures::known().supports_gossip_queries()); + assert!(NodeFeatures::known().supports_gossip_queries()); + assert!(!InitFeatures::known().requires_gossip_queries()); + assert!(!NodeFeatures::known().requires_gossip_queries()); assert!(InitFeatures::known().supports_data_loss_protect()); assert!(NodeFeatures::known().supports_data_loss_protect()); + assert!(!InitFeatures::known().requires_data_loss_protect()); + assert!(!NodeFeatures::known().requires_data_loss_protect()); assert!(InitFeatures::known().supports_variable_length_onion()); assert!(NodeFeatures::known().supports_variable_length_onion()); + assert!(!InitFeatures::known().requires_variable_length_onion()); + assert!(!NodeFeatures::known().requires_variable_length_onion()); + + assert!(InitFeatures::known().supports_static_remote_key()); + assert!(NodeFeatures::known().supports_static_remote_key()); + assert!(InitFeatures::known().requires_static_remote_key()); + assert!(NodeFeatures::known().requires_static_remote_key()); assert!(InitFeatures::known().supports_payment_secret()); assert!(NodeFeatures::known().supports_payment_secret()); + assert!(!InitFeatures::known().requires_payment_secret()); + assert!(!NodeFeatures::known().requires_payment_secret()); assert!(InitFeatures::known().supports_basic_mpp()); assert!(NodeFeatures::known().supports_basic_mpp()); + assert!(!InitFeatures::known().requires_basic_mpp()); + assert!(!NodeFeatures::known().requires_basic_mpp()); + + assert!(InitFeatures::known().supports_shutdown_anysegwit()); + assert!(NodeFeatures::known().supports_shutdown_anysegwit()); let mut init_features = InitFeatures::known(); assert!(init_features.initial_routing_sync()); @@ -494,35 +683,63 @@ mod tests { } #[test] - fn sanity_test_unkown_bits_testing() { - let mut features = ChannelFeatures::known(); - features.set_require_unknown_bits(); + fn sanity_test_unknown_bits() { + let mut features = ChannelFeatures::empty(); + assert!(!features.requires_unknown_bits()); + assert!(!features.supports_unknown_bits()); + + features.set_required_unknown_bits(); assert!(features.requires_unknown_bits()); - features.clear_require_unknown_bits(); + assert!(features.supports_unknown_bits()); + + features.clear_unknown_bits(); assert!(!features.requires_unknown_bits()); + assert!(!features.supports_unknown_bits()); + + features.set_optional_unknown_bits(); + assert!(!features.requires_unknown_bits()); + assert!(features.supports_unknown_bits()); } #[test] - fn test_node_with_known_relevant_init_flags() { - // Create an InitFeatures with initial_routing_sync supported. - let init_features = InitFeatures::known(); + fn convert_to_context_with_relevant_flags() { + let init_features = InitFeatures::known().clear_upfront_shutdown_script().clear_gossip_queries(); assert!(init_features.initial_routing_sync()); + assert!(!init_features.supports_upfront_shutdown_script()); + assert!(!init_features.supports_gossip_queries()); - // Attempt to pull out non-node-context feature flags from these InitFeatures. - let res = NodeFeatures::with_known_relevant_init_flags(&init_features); - + let node_features: NodeFeatures = init_features.to_context(); { - // Check that the flags are as expected: optional_data_loss_protect, - // option_upfront_shutdown_script, var_onion_optin, payment_secret, and - // basic_mpp. - assert_eq!(res.flags.len(), 3); - assert_eq!(res.flags[0], 0b00100010); - assert_eq!(res.flags[1], 0b10000010); - assert_eq!(res.flags[2], 0b00000010); + // Check that the flags are as expected: + // - option_data_loss_protect + // - var_onion_optin | static_remote_key (req) | payment_secret + // - basic_mpp + // - opt_shutdown_anysegwit + assert_eq!(node_features.flags.len(), 4); + assert_eq!(node_features.flags[0], 0b00000010); + assert_eq!(node_features.flags[1], 0b10010010); + assert_eq!(node_features.flags[2], 0b00000010); + assert_eq!(node_features.flags[3], 0b00001000); } - // Check that the initial_routing_sync feature was correctly blanked out. - let new_features: InitFeatures = Features::from_le_bytes(res.flags); - assert!(!new_features.initial_routing_sync()); + // 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 set_feature_bits() { + let features = InvoiceFeatures::empty() + .set_basic_mpp_optional() + .set_payment_secret_required(); + assert!(features.supports_basic_mpp()); + assert!(!features.requires_basic_mpp()); + assert!(features.requires_payment_secret()); + assert!(features.supports_payment_secret()); } }