X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=eb0100db675de8842e1d317d4a2b9c5c6e7b9ab1;hb=0328be32f7331d447eefae062ea94dec99f47cad;hp=c97e18100fc769fd906a201f4868f3e662d21852;hpb=de58bcf27125a0269c62606ded161d57c016fe6e;p=rust-lightning diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs index c97e1810..eb0100db 100644 --- a/lightning/src/ln/features.rs +++ b/lightning/src/ln/features.rs @@ -12,8 +12,7 @@ //! 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 @@ -21,21 +20,23 @@ //! 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::marker::PhantomData; +use prelude::*; +use core::{cmp, fmt}; +use core::marker::PhantomData; +use bitcoin::bech32; +use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32}; use ln::msgs::DecodeError; use util::ser::{Readable, Writeable, Writer}; mod sealed { + use prelude::*; + 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. @@ -49,13 +50,12 @@ 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 { ($context: ident { required_features: [$( $( $required_feature: ident )|*, )*], optional_features: [$( $( $optional_feature: ident )|*, )*], }) => { + #[derive(Eq, PartialEq)] pub struct $context {} impl Context for $context { @@ -97,17 +97,21 @@ mod sealed { // Byte 0 , // Byte 1 - StaticRemoteKey, + VariableLengthOnion | StaticRemoteKey | PaymentSecret, // Byte 2 , + // Byte 3 + , ], optional_features: [ // Byte 0 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries, // Byte 1 - VariableLengthOnion | PaymentSecret, + , // Byte 2 BasicMPP, + // Byte 3 + ShutdownAnySegwit, ], }); define_context!(NodeContext { @@ -115,30 +119,63 @@ mod sealed { // Byte 0 , // Byte 1 - StaticRemoteKey, + VariableLengthOnion | StaticRemoteKey | PaymentSecret, // Byte 2 , + // Byte 3 + , + // Byte 4 + , + // Byte 5 + , + // Byte 6 + , ], optional_features: [ // Byte 0 DataLossProtect | UpfrontShutdownScript | GossipQueries, // Byte 1 - VariableLengthOnion | PaymentSecret, + , // Byte 2 BasicMPP, + // Byte 3 + ShutdownAnySegwit, + // Byte 4 + , + // Byte 5 + , + // Byte 6 + Keysend, ], }); define_context!(ChannelContext { required_features: [], optional_features: [], }); + define_context!(InvoiceContext { + required_features: [ + // Byte 0 + , + // Byte 1 + VariableLengthOnion | PaymentSecret, + // Byte 2 + , + ], + optional_features: [ + // Byte 0 + , + // Byte 1 + , + // Byte 2 + BasicMPP, + ], + }); /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is /// useful for manipulating feature flags. - /// - /// [`Context`]: trait.Context.html macro_rules! define_feature { - ($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. @@ -223,6 +260,20 @@ mod sealed { } } + 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 + } + } + $( impl $feature for $context { // EVEN_BIT % 2 == 0 @@ -232,56 +283,48 @@ 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`."); + "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`."); - define_feature!(9, VariableLengthOnion, [InitContext, NodeContext], - "Feature flags for `var_onion_optin`."); + "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`."); - define_feature!(15, PaymentSecret, [InitContext, NodeContext], - "Feature flags for `payment_secret`."); - define_feature!(17, BasicMPP, [InitContext, NodeContext], - "Feature flags for `basic_mpp`."); - - #[cfg(test)] - define_context!(TestingContext { - required_features: [ - // Byte 0 - , - // Byte 1 - , - // Byte 2 - UnknownFeature, - ], - optional_features: [ - // Byte 0 - , - // Byte 1 - , - // Byte 2 - , - ], - }); + "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); + define_feature!(55, Keysend, [NodeContext], + "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required); #[cfg(test)] - define_feature!(23, UnknownFeature, [TestingContext], - "Feature flags for an unknown feature used in testing."); + define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext], + "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 +#[derive(Eq)] pub struct Features { /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire) flags: Vec, @@ -313,6 +356,8 @@ 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. @@ -349,6 +394,88 @@ impl InitFeatures { } } +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() + } + + /// Getting a route for a keysend payment to a private node requires providing the payee's + /// features (since they were not announced in a node announcement). However, keysend payments + /// don't have an invoice to pull the payee's features from, so this method is provided for use in + /// [`get_keysend_route`], thus omitting the need for payers to manually construct an + /// `InvoiceFeatures` for [`get_route`]. + /// + /// [`get_keysend_route`]: crate::routing::router::get_keysend_route + /// [`get_route`]: crate::routing::router::get_route + pub(crate) fn for_keysend() -> InvoiceFeatures { + InvoiceFeatures::empty().set_variable_length_onion_optional() + } +} + +impl ToBase32 for InvoiceFeatures { + fn write_base32(&self, writer: &mut W) -> Result<(), ::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 = 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 InvoiceFeatures { + fn base32_len(&self) -> usize { + self.to_base32().len() + } +} + +impl FromBase32 for InvoiceFeatures { + type Err = bech32::Error; + + fn from_base32(field_data: &[u5]) -> Result { + // 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 = 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(InvoiceFeatures::from_le_bytes(res_bytes)) + } +} + impl Features { /// Create a blank Features with no features set pub fn empty() -> Self { @@ -358,9 +485,7 @@ impl Features { } } - /// 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 + /// 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(), @@ -371,20 +496,22 @@ impl Features { /// 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 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 < byte_count { - 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); + 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:: { flags, mark: PhantomData, } } - #[cfg(test)] - /// Create a Features given a set of flags, in LE. + /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from + /// most on-the-wire encodings. + /// (C-not exported) as we don't support export across multiple T pub fn from_le_bytes(flags: Vec) -> Features { Features { flags, @@ -432,21 +559,6 @@ impl Features { pub(crate) fn byte_count(&self) -> usize { self.flags.len() } - - #[cfg(test)] - pub(crate) fn set_required_unknown_bits(&mut self) { - ::set_required_bit(&mut self.flags); - } - - #[cfg(test)] - 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 { @@ -528,11 +640,8 @@ impl Features { 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 { + /// Returns whether the `payment_secret` feature is supported. + pub fn supports_payment_secret(&self) -> bool { ::supports_feature(&self.flags) } } @@ -543,12 +652,22 @@ impl Features { ::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); @@ -573,7 +692,8 @@ impl Readable for Features { #[cfg(test)] mod tests { - use super::{ChannelFeatures, InitFeatures, NodeFeatures}; + use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures}; + use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5}; #[test] fn sanity_test_known_features() { @@ -601,8 +721,10 @@ mod tests { 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!(InvoiceFeatures::known().supports_variable_length_onion()); + assert!(InitFeatures::known().requires_variable_length_onion()); + assert!(NodeFeatures::known().requires_variable_length_onion()); + assert!(InvoiceFeatures::known().requires_variable_length_onion()); assert!(InitFeatures::known().supports_static_remote_key()); assert!(NodeFeatures::known().supports_static_remote_key()); @@ -611,13 +733,20 @@ mod tests { 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!(InvoiceFeatures::known().supports_payment_secret()); + assert!(InitFeatures::known().requires_payment_secret()); + assert!(NodeFeatures::known().requires_payment_secret()); + assert!(InvoiceFeatures::known().requires_payment_secret()); assert!(InitFeatures::known().supports_basic_mpp()); assert!(NodeFeatures::known().supports_basic_mpp()); + assert!(InvoiceFeatures::known().supports_basic_mpp()); assert!(!InitFeatures::known().requires_basic_mpp()); assert!(!NodeFeatures::known().requires_basic_mpp()); + assert!(!InvoiceFeatures::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()); @@ -627,19 +756,15 @@ mod tests { #[test] fn sanity_test_unknown_bits() { - let mut features = ChannelFeatures::empty(); + let features = ChannelFeatures::empty(); assert!(!features.requires_unknown_bits()); assert!(!features.supports_unknown_bits()); - features.set_required_unknown_bits(); + let features = ChannelFeatures::empty().set_unknown_feature_required(); assert!(features.requires_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(); + let features = ChannelFeatures::empty().set_unknown_feature_optional(); assert!(!features.requires_unknown_bits()); assert!(features.supports_unknown_bits()); } @@ -655,12 +780,14 @@ mod tests { { // Check that the flags are as expected: // - option_data_loss_protect - // - var_onion_optin | static_remote_key (req) | payment_secret + // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req) // - basic_mpp - assert_eq!(node_features.flags.len(), 3); + // - 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[1], 0b01010001); assert_eq!(node_features.flags[2], 0b00000010); + assert_eq!(node_features.flags[3], 0b00001000); } // Check that cleared flags are kept blank when converting back: @@ -672,4 +799,56 @@ mod tests { 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!(InvoiceFeatures::known().byte_count() < NodeFeatures::known().byte_count()); + let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional(); + assert!(invoice_features.supports_unknown_bits()); + let node_features: NodeFeatures = invoice_features.to_context(); + assert!(!node_features.supports_unknown_bits()); + } + + #[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()); + } + + #[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 = InvoiceFeatures::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 = InvoiceFeatures::from_base32(&features_as_u5s).unwrap(); + assert_eq!(features, features_deserialized); + } }