//! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
//! [messages]: crate::ln::msgs
-use {io, io_extras};
-use prelude::*;
+use crate::{io, io_extras};
+use crate::prelude::*;
use core::{cmp, fmt};
use core::hash::{Hash, Hasher};
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};
+use crate::ln::msgs::DecodeError;
+use crate::util::ser::{Readable, Writeable, Writer};
mod sealed {
- use prelude::*;
- use ln::features::Features;
+ use crate::prelude::*;
+ use crate::ln::features::Features;
- /// The context in which [`Features`] are applicable. Defines which features are required and
- /// which are optional for the context.
+ /// 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 {
- /// 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.
+ /// Bitmask for selecting features that are known to the implementation.
const KNOWN_FEATURE_MASK: &'static [u8];
}
/// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
/// feature identifiers.
macro_rules! define_context {
- ($context: ident {
- required_features: [$( $( $required_feature: ident )|*, )*],
- optional_features: [$( $( $optional_feature: ident )|*, )*],
- }) => {
+ ($context: ident, [$( $( $known_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 $(|
- <Self as $required_feature>::REQUIRED_MASK)*
- $(|
- <Self as $optional_feature>::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 $(|
- <Self as $required_feature>::REQUIRED_MASK |
- <Self as $required_feature>::OPTIONAL_MASK)*
- $(|
- <Self as $optional_feature>::REQUIRED_MASK |
- <Self as $optional_feature>::OPTIONAL_MASK)*,
+ <Self as $known_feature>::REQUIRED_MASK |
+ <Self as $known_feature>::OPTIONAL_MASK)*,
)*
];
}
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 $optional_feature>::supports_feature(&self.flags) { "supported" }
+ fmt.write_fmt(format_args!("{}: {}, ", stringify!($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" }
};
}
- define_context!(InitContext {
- required_features: [
- // Byte 0
- ,
- // Byte 1
- VariableLengthOnion | StaticRemoteKey | PaymentSecret,
- // Byte 2
- ,
- // Byte 3
- ,
- // Byte 4
- ,
- // Byte 5
- ,
- // Byte 6
- ,
- ],
- optional_features: [
- // Byte 0
- DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
- // Byte 1
- ,
- // Byte 2
- BasicMPP | Wumbo,
- // Byte 3
- ShutdownAnySegwit,
- // Byte 4
- OnionMessages,
- // Byte 5
- ChannelType | SCIDPrivacy,
- // Byte 6
- ZeroConf,
- ],
- });
- 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 | Wumbo,
- // Byte 3
- ShutdownAnySegwit,
- // Byte 4
- OnionMessages,
- // Byte 5
- ChannelType | SCIDPrivacy,
- // Byte 6
- ZeroConf | 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,
- ],
- });
+ define_context!(InitContext, [
+ // Byte 0
+ DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
+ // Byte 1
+ VariableLengthOnion | StaticRemoteKey | PaymentSecret,
+ // Byte 2
+ BasicMPP | Wumbo,
+ // Byte 3
+ ShutdownAnySegwit,
+ // Byte 4
+ OnionMessages,
+ // Byte 5
+ ChannelType | SCIDPrivacy,
+ // Byte 6
+ ZeroConf,
+ ]);
+ define_context!(NodeContext, [
+ // Byte 0
+ DataLossProtect | UpfrontShutdownScript | GossipQueries,
+ // Byte 1
+ VariableLengthOnion | StaticRemoteKey | PaymentSecret,
+ // Byte 2
+ BasicMPP | Wumbo,
+ // Byte 3
+ ShutdownAnySegwit,
+ // Byte 4
+ OnionMessages,
+ // Byte 5
+ ChannelType | SCIDPrivacy,
+ // Byte 6
+ ZeroConf | Keysend,
+ ]);
+ define_context!(ChannelContext, []);
+ define_context!(InvoiceContext, [
+ // Byte 0
+ ,
+ // Byte 1
+ VariableLengthOnion | PaymentSecret,
+ // Byte 2
+ BasicMPP,
+ ]);
+ define_context!(OfferContext, []);
// This isn't a "real" feature context, and is only used in the channel_type field in an
// `OpenChannel` message.
- define_context!(ChannelTypeContext {
- required_features: [
- // Byte 0
- ,
- // Byte 1
- StaticRemoteKey,
- // Byte 2
- ,
- // Byte 3
- ,
- // Byte 4
- ,
- // Byte 5
- SCIDPrivacy,
- // Byte 6
- ZeroConf,
- ],
- optional_features: [
- // Byte 0
- ,
- // Byte 1
- ,
- // Byte 2
- ,
- // Byte 3
- ,
- // Byte 4
- ,
- // Byte 5
- ,
- // Byte 6
- ,
- ],
- });
+ define_context!(ChannelTypeContext, [
+ // Byte 0
+ ,
+ // Byte 1
+ StaticRemoteKey,
+ // Byte 2
+ ,
+ // Byte 3
+ ,
+ // 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.
/// [`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;
// 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 $feature>::EVEN_BIT % 8)) - 3;
}
)*
};
supports_keysend, requires_keysend);
#[cfg(test)]
- define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
+ define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext, OfferContext],
"Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
set_unknown_feature_required, supports_unknown_test_feature, requires_unknown_test_feature);
}
pub type ChannelFeatures = Features<sealed::ChannelContext>;
/// Features used within an invoice.
pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
+/// Features used within an offer.
+pub type OfferFeatures = Features<sealed::OfferContext>;
/// Features used within the channel_type field in an OpenChannel message.
///
}
}
+#[cfg(test)]
+impl<T: sealed::UnknownFeature> Features<T> {
+ pub(crate) fn unknown() -> Self {
+ let mut features = Self::empty();
+ features.set_unknown_feature_required();
+ features
+ }
+}
+
macro_rules! impl_feature_len_prefixed_write {
($features: ident) => {
impl Writeable for $features {
impl_feature_len_prefixed_write!(NodeFeatures);
impl_feature_len_prefixed_write!(InvoiceFeatures);
-// Because ChannelTypeFeatures only appears inside of TLVs, it doesn't have a length prefix when
-// serialized. Thus, we can't use `impl_feature_len_prefixed_write`, above, and have to write our
-// own serialization.
-impl Writeable for ChannelTypeFeatures {
- fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
- self.write_be(w)
- }
-}
-impl Readable for ChannelTypeFeatures {
- fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
- let v = io_extras::read_to_end(r)?;
- Ok(Self::from_be_bytes(v))
+// Some features only appear inside of TLVs, so they don't have a length prefix when serialized.
+macro_rules! impl_feature_tlv_write {
+ ($features: ident) => {
+ impl Writeable for $features {
+ fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+ self.write_be(w)
+ }
+ }
+ impl Readable for $features {
+ fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+ let v = io_extras::read_to_end(r)?;
+ Ok(Self::from_be_bytes(v))
+ }
+ }
}
}
+impl_feature_tlv_write!(ChannelTypeFeatures);
+impl_feature_tlv_write!(OfferFeatures);
+
#[cfg(test)]
mod tests {
use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, InvoiceFeatures, NodeFeatures, sealed};
projects / rust-lightning / blobdiff