X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Ffeatures.rs;h=e78fa3d50d2d05c5bfcafe1fd58eb1b654c167f7;hb=0dfcacd22c23f69b6526c9c6507d21427a2b7ccb;hp=4f45b9338c62c4e84c03e5223abcb248717e195e;hpb=a3ddb9fb19f68584c1724328931afbef37e9f172;p=rust-lightning diff --git a/lightning/src/ln/features.rs b/lightning/src/ln/features.rs index 4f45b933..e78fa3d5 100644 --- a/lightning/src/ln/features.rs +++ b/lightning/src/ln/features.rs @@ -1,44 +1,355 @@ -//! Lightning exposes sets of supported operations through "feature flags". This module includes -//! types to store those feature flags and query for specific flags. - -use std::{cmp, fmt}; -use std::result::Result; -use std::marker::PhantomData; - +// 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). +//! +//! 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. +//! +//! [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md +//! [messages]: crate::ln::msgs + +use io; +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 { // You should just use the type aliases instead. - pub struct InitContext {} - pub struct NodeContext {} - pub struct ChannelContext {} +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. + 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. + const KNOWN_FEATURE_FLAGS: &'static [u8]; + + /// Bitmask for selecting features that are known to the implementation, regardless of + /// whether each feature is required or optional. + const KNOWN_FEATURE_MASK: &'static [u8]; + } - /// An internal trait capturing the various feature context types - pub trait Context {} - impl Context for InitContext {} - impl Context for NodeContext {} - impl Context for ChannelContext {} + /// 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 { + ($context: ident { + required_features: [$( $( $required_feature: ident )|*, )*], + optional_features: [$( $( $optional_feature: ident )|*, )*], + }) => { + #[derive(Eq, PartialEq)] + pub struct $context {} + + impl Context for $context { + const KNOWN_FEATURE_FLAGS: &'static [u8] = &[ + // For each byte, use bitwise-OR to compute the applicable flags for known + // required features `r_i` and optional features `o_j` for all `i` and `j` such + // that the following slice is formed: + // + // [ + // `r_0` | `r_1` | ... | `o_0` | `o_1` | ..., + // ..., + // ] + $( + 0b00_00_00_00 $(| + ::REQUIRED_MASK)* + $(| + ::OPTIONAL_MASK)*, + )* + ]; + + const KNOWN_FEATURE_MASK: &'static [u8] = &[ + // Similar as above, but set both flags for each feature regardless of whether + // the feature is required or optional. + $( + 0b00_00_00_00 $(| + ::REQUIRED_MASK | + ::OPTIONAL_MASK)* + $(| + ::REQUIRED_MASK | + ::OPTIONAL_MASK)*, + )* + ]; + } - pub trait DataLossProtect: Context {} - impl DataLossProtect for InitContext {} - impl DataLossProtect for NodeContext {} + impl alloc::fmt::Display for Features<$context> { + fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> { + $( + $( + fmt.write_fmt(format_args!("{}: {}, ", stringify!($required_feature), + if <$context as $required_feature>::requires_feature(&self.flags) { "required" } + else if <$context as $required_feature>::supports_feature(&self.flags) { "supported" } + else { "not supported" }))?; + )* + $( + fmt.write_fmt(format_args!("{}: {}, ", stringify!($optional_feature), + if <$context as $optional_feature>::requires_feature(&self.flags) { "required" } + else if <$context as $optional_feature>::supports_feature(&self.flags) { "supported" } + else { "not supported" }))?; + )* + )* + fmt.write_fmt(format_args!("unknown flags: {}", + if self.requires_unknown_bits() { "required" } + else if self.supports_unknown_bits() { "supported" } else { "none" })) + } + } + }; + } - pub trait InitialRoutingSync: Context {} - impl InitialRoutingSync for InitContext {} + define_context!(InitContext { + required_features: [ + // Byte 0 + , + // Byte 1 + VariableLengthOnion | StaticRemoteKey | PaymentSecret, + // Byte 2 + , + // Byte 3 + , + ], + optional_features: [ + // Byte 0 + DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries, + // Byte 1 + , + // Byte 2 + BasicMPP, + // Byte 3 + ShutdownAnySegwit, + ], + }); + define_context!(NodeContext { + required_features: [ + // Byte 0 + , + // Byte 1 + VariableLengthOnion | StaticRemoteKey | PaymentSecret, + // Byte 2 + , + // Byte 3 + , + // Byte 4 + , + // Byte 5 + , + // Byte 6 + , + ], + optional_features: [ + // Byte 0 + DataLossProtect | UpfrontShutdownScript | GossipQueries, + // Byte 1 + , + // Byte 2 + BasicMPP, + // Byte 3 + ShutdownAnySegwit, + // Byte 4 + , + // Byte 5 + , + // Byte 6 + Keysend, + ], + }); + define_context!(ChannelContext { + required_features: [], + optional_features: [], + }); + define_context!(InvoiceContext { + required_features: [ + // Byte 0 + , + // Byte 1 + VariableLengthOnion | PaymentSecret, + // Byte 2 + , + ], + optional_features: [ + // Byte 0 + , + // Byte 1 + , + // Byte 2 + BasicMPP, + ], + }); + + /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is + /// useful for manipulating feature flags. + macro_rules! define_feature { + ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident, + $required_setter: ident) => { + #[doc = $doc] + /// + /// See [BOLT #9] for details. + /// + /// [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/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; + + /// 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) -> 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 { + 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) { + 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) { + 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) { + 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 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 + const ASSERT_EVEN_BIT_PARITY: usize = 0 - (::EVEN_BIT % 2); + + // ODD_BIT % 2 == 1 + const ASSERT_ODD_BIT_PARITY: usize = (::ODD_BIT % 2) - 1; + } + )* + + } + } - pub trait UpfrontShutdownScript: Context {} - impl UpfrontShutdownScript for InitContext {} - impl UpfrontShutdownScript for NodeContext {} + define_feature!(1, DataLossProtect, [InitContext, NodeContext], + "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`.", + set_initial_routing_sync_optional, set_initial_routing_sync_required); + define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext], + "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); + define_feature!(55, Keysend, [NodeContext], + "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required); - pub trait VariableLengthOnion: Context {} - impl VariableLengthOnion for InitContext {} - impl VariableLengthOnion for NodeContext {} + #[cfg(test)] + define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext], + "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional, + set_unknown_feature_required); } /// 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 convinience, flags is LITTLE endian (despite being big-endian on the wire) + /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire) flags: Vec, mark: PhantomData, } @@ -62,24 +373,18 @@ impl fmt::Debug for Features { } } -/// A feature message as it appears in an init message +/// Features used within an `init` message. pub type InitFeatures = Features; -/// A feature message as it appears in a node_announcement message +/// Features used within a `node_announcement` message. pub type NodeFeatures = Features; -/// A feature message as it appears in a channel_announcement message +/// Features used within a `channel_announcement` message. pub type ChannelFeatures = Features; +/// Features used within an invoice. +pub type InvoiceFeatures = Features; impl InitFeatures { - /// Create a Features with the features we support - pub fn supported() -> InitFeatures { - InitFeatures { - flags: vec![2 | 1 << 5, 1 << (9-8)], - mark: PhantomData, - } - } - /// Writes all features present up to, and including, 13. - pub(crate) fn write_up_to_13(&self, w: &mut W) -> Result<(), ::std::io::Error> { + pub(crate) fn write_up_to_13(&self, w: &mut W) -> Result<(), io::Error> { let len = cmp::min(2, self.flags.len()); w.size_hint(len + 2); (len as u16).write(w)?; @@ -104,73 +409,132 @@ impl InitFeatures { } self } -} -impl ChannelFeatures { - /// Create a Features with the features we support - #[cfg(not(feature = "fuzztarget"))] - pub(crate) fn supported() -> ChannelFeatures { - ChannelFeatures { - flags: Vec::new(), - mark: PhantomData, - } + /// 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() } - #[cfg(feature = "fuzztarget")] - pub fn supported() -> ChannelFeatures { - ChannelFeatures { - flags: Vec::new(), - mark: PhantomData, - } +} + +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() } - /// Takes the flags that we know how to interpret in an init-context features that are also - /// relevant in a channel-context features and creates a channel-context features from them. - pub(crate) fn with_known_relevant_init_flags(_init_ctx: &InitFeatures) -> Self { - // There are currently no channel flags defined that we understand. - Self { flags: Vec::new(), mark: PhantomData, } + /// 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 NodeFeatures { - /// Create a Features with the features we support - #[cfg(not(feature = "fuzztarget"))] - pub(crate) fn supported() -> NodeFeatures { - NodeFeatures { - flags: vec![2 | 1 << 5, 1 << (9-8)], - mark: PhantomData, +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(); + } } - } - #[cfg(feature = "fuzztarget")] - pub fn supported() -> NodeFeatures { - NodeFeatures { - flags: vec![2 | 1 << 5, 1 << (9-8)], - mark: PhantomData, + // 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) } +} - /// 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. - pub(crate) fn with_known_relevant_init_flags(init_ctx: &InitFeatures) -> Self { - let mut flags = Vec::new(); - if init_ctx.flags.len() > 0 { - // Pull out data_loss_protect and upfront_shutdown_script (bits 0, 1, 4, and 5) - flags.push(init_ctx.flags.last().unwrap() & 0b00110011); +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(); } - Self { flags, mark: PhantomData, } + Ok(InvoiceFeatures::from_le_bytes(res_bytes)) } } impl Features { /// Create a blank Features with no features set - pub fn empty() -> Features { + pub fn empty() -> Self { Features { flags: Vec::new(), mark: PhantomData, } } - #[cfg(test)] - /// Create a Features given a set of flags, in LE. + /// 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, + } + } + + /// Converts `Features` to `Features`. Only known `T` features relevant to context `C` are + /// included in the result. + fn to_context_internal(&self) -> Features { + 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:: { 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. + /// (C-not exported) as we don't support export across multiple T pub fn from_le_bytes(flags: Vec) -> Features { Features { flags, @@ -185,31 +549,31 @@ impl Features { } pub(crate) fn requires_unknown_bits(&self) -> bool { - self.flags.iter().enumerate().any(|(idx, &byte)| { - (match idx { - // Unknown bits are even bits which we don't understand, we list ones which we do - // here: - // unknown, upfront_shutdown_script, unknown (actually initial_routing_sync, but it - // is only valid as an optional feature), and data_loss_protect: - 0 => (byte & 0b01000100), - // unknown, unknown, unknown, var_onion_optin: - 1 => (byte & 0b01010100), - // fallback, all even bits set: - _ => (byte & 0b01010101), - }) != 0 + // Bitwise AND-ing with all even bits set except for known features will select required + // unknown features. + let byte_count = T::KNOWN_FEATURE_MASK.len(); + self.flags.iter().enumerate().any(|(i, &byte)| { + let required_features = 0b01_01_01_01; + let unknown_features = if i < byte_count { + !T::KNOWN_FEATURE_MASK[i] + } else { + 0b11_11_11_11 + }; + (byte & (required_features & unknown_features)) != 0 }) } pub(crate) fn supports_unknown_bits(&self) -> bool { - self.flags.iter().enumerate().any(|(idx, &byte)| { - (match idx { - // unknown, upfront_shutdown_script, initial_routing_sync (is only valid as an - // optional feature), and data_loss_protect: - 0 => (byte & 0b11000100), - // unknown, unknown, unknown, var_onion_optin: - 1 => (byte & 0b11111100), - _ => byte, - }) != 0 + // 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 }) } @@ -218,62 +582,118 @@ impl Features { pub(crate) fn byte_count(&self) -> usize { self.flags.len() } +} +impl Features { #[cfg(test)] - pub(crate) fn set_require_unknown_bits(&mut self) { - let newlen = cmp::max(2, self.flags.len()); - self.flags.resize(newlen, 0u8); - self.flags[1] |= 0x40; + pub(crate) fn requires_data_loss_protect(&self) -> bool { + ::requires_feature(&self.flags) } - #[cfg(test)] - pub(crate) fn clear_require_unknown_bits(&mut self) { - let newlen = cmp::max(2, self.flags.len()); - self.flags.resize(newlen, 0u8); - self.flags[1] &= !0x40; - if self.flags.len() == 2 && self.flags[1] == 0 { - self.flags.resize(1, 0u8); - } - } -} - -impl Features { pub(crate) fn supports_data_loss_protect(&self) -> bool { - self.flags.len() > 0 && (self.flags[0] & 3) != 0 + ::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 { - self.flags.len() > 0 && (self.flags[0] & (3 << 4)) != 0 + ::supports_feature(&self.flags) } #[cfg(test)] - pub(crate) fn unset_upfront_shutdown_script(&mut self) { - self.flags[0] ^= 1 << 5; + 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 { - self.flags.len() > 1 && (self.flags[1] & 3) != 0 + ::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 { - self.flags.len() > 0 && (self.flags[0] & (1 << 3)) != 0 + ::supports_feature(&self.flags) } - pub(crate) fn set_initial_routing_sync(&mut self) { - if self.flags.len() == 0 { - self.flags.resize(1, 1 << 3); - } else { - self.flags[0] |= 1 << 3; - } + // 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 { + #[cfg(test)] + pub(crate) fn requires_payment_secret(&self) -> bool { + ::requires_feature(&self.flags) + } + /// Returns whether the `payment_secret` feature is supported. + pub 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. + 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> { + fn write(&self, w: &mut W) -> Result<(), io::Error> { w.size_hint(self.flags.len() + 2); (self.flags.len() as u16).write(w)?; for f in self.flags.iter().rev() { // Swap back to big-endian @@ -283,8 +703,8 @@ impl Writeable for Features { } } -impl Readable for Features { - fn read(r: &mut R) -> Result { +impl Readable for Features { + fn read(r: &mut R) -> Result { let mut flags: Vec = Readable::read(r)?; flags.reverse(); // Swap to little-endian Ok(Self { @@ -293,3 +713,166 @@ impl Readable for Features { }) } } + +#[cfg(test)] +mod tests { + use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures}; + use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5}; + + #[test] + fn sanity_test_known_features() { + assert!(!ChannelFeatures::known().requires_unknown_bits()); + assert!(!ChannelFeatures::known().supports_unknown_bits()); + assert!(!InitFeatures::known().requires_unknown_bits()); + assert!(!InitFeatures::known().supports_unknown_bits()); + assert!(!NodeFeatures::known().requires_unknown_bits()); + assert!(!NodeFeatures::known().supports_unknown_bits()); + + 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!(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()); + 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!(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()); + init_features.clear_initial_routing_sync(); + assert!(!init_features.initial_routing_sync()); + } + + #[test] + fn sanity_test_unknown_bits() { + let features = ChannelFeatures::empty(); + assert!(!features.requires_unknown_bits()); + assert!(!features.supports_unknown_bits()); + + let features = ChannelFeatures::empty().set_unknown_feature_required(); + assert!(features.requires_unknown_bits()); + assert!(features.supports_unknown_bits()); + + let features = ChannelFeatures::empty().set_unknown_feature_optional(); + assert!(!features.requires_unknown_bits()); + assert!(features.supports_unknown_bits()); + } + + #[test] + 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()); + + let node_features: NodeFeatures = init_features.to_context(); + { + // Check that the flags are as expected: + // - option_data_loss_protect + // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req) + // - 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], 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: + // - 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!(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); + } +}