-/// The context in which a Feature object appears determines which bits of features the node
-/// supports will be set. We use this when creating our own Feature objects to select which bits to
-/// set and when passing around Feature objects to ensure the bits we're checking for are
-/// available.
-///
-/// This Context represents when the Feature appears in the init message, sent between peers and not
-/// rumored around the P2P network.
-pub struct FeatureContextInit {}
-/// The context in which a Feature object appears determines which bits of features the node
-/// supports will be set. We use this when creating our own Feature objects to select which bits to
-/// set and when passing around Feature objects to ensure the bits we're checking for are
-/// available.
-///
-/// This Context represents when the Feature appears in the node_announcement message, as it is
-/// rumored around the P2P network.
-pub struct FeatureContextNode {}
-/// The context in which a Feature object appears determines which bits of features the node
-/// supports will be set. We use this when creating our own Feature objects to select which bits to
-/// set and when passing around Feature objects to ensure the bits we're checking for are
-/// available.
-///
-/// This Context represents when the Feature appears in the ChannelAnnouncement message, as it is
-/// rumored around the P2P network.
-pub struct FeatureContextChannel {}
-/// The context in which a Feature object appears determines which bits of features the node
-/// supports will be set. We use this when creating our own Feature objects to select which bits to
-/// set and when passing around Feature objects to ensure the bits we're checking for are
-/// available.
-///
-/// This Context represents when the Feature appears in an invoice, used to determine the different
-/// options available for routing a payment.
-///
-/// Note that this is currently unused as invoices come to us via a different crate and are not
-/// native to rust-lightning directly.
-pub struct FeatureContextInvoice {}
-
-/// An internal trait capturing the various future context types
-pub trait FeatureContext {}
-impl FeatureContext for FeatureContextInit {}
-impl FeatureContext for FeatureContextNode {}
-impl FeatureContext for FeatureContextChannel {}
-impl FeatureContext for FeatureContextInvoice {}
-
-/// An internal trait capturing FeatureContextInit and FeatureContextNode
-pub trait FeatureContextInitNode : FeatureContext {}
-impl FeatureContextInitNode for FeatureContextInit {}
-impl FeatureContextInitNode for FeatureContextNode {}
-
-/// Tracks the set of features which a node implements, templated by the context in which it
-/// appears.
-pub struct Features<T: FeatureContext> {
- #[cfg(not(test))]
- /// Note that, for convinience, flags is LITTLE endian (despite being big-endian on the wire)
- flags: Vec<u8>,
- // Used to test encoding of diverse msgs
- #[cfg(test)]
- pub flags: Vec<u8>,
- mark: PhantomData<T>,
-}
-
-impl<T: FeatureContext> Clone for Features<T> {
- fn clone(&self) -> Self {
- Self {
- flags: self.flags.clone(),
- mark: PhantomData,
- }
- }
-}
-impl<T: FeatureContext> PartialEq for Features<T> {
- fn eq(&self, o: &Self) -> bool {
- self.flags.eq(&o.flags)
- }
-}
-impl<T: FeatureContext> fmt::Debug for Features<T> {
- fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
- self.flags.fmt(fmt)
- }
-}
-
-/// A feature message as it appears in an init message
-pub type InitFeatures = Features<FeatureContextInit>;
-/// A feature message as it appears in a node_announcement message
-pub type NodeFeatures = Features<FeatureContextNode>;
-/// A feature message as it appears in a channel_announcement message
-pub type ChannelFeatures = Features<FeatureContextChannel>;
-
-impl<T: FeatureContextInitNode> Features<T> {
- /// Create a Features with the features we support
- #[cfg(not(feature = "fuzztarget"))]
- pub(crate) fn supported() -> Features<T> {
- Features {
- flags: vec![2 | 1 << 5],
- mark: PhantomData,
- }
- }
- #[cfg(feature = "fuzztarget")]
- pub fn supported() -> Features<T> {
- Features {
- flags: vec![2 | 1 << 5],
- mark: PhantomData,
- }
- }
-}
-
-impl Features<FeatureContextChannel> {
- /// Create a Features with the features we support
- #[cfg(not(feature = "fuzztarget"))]
- pub(crate) fn supported() -> Features<FeatureContextChannel> {
- Features {
- flags: Vec::new(),
- mark: PhantomData,
- }
- }
- #[cfg(feature = "fuzztarget")]
- pub fn supported() -> Features<FeatureContextChannel> {
- Features {
- flags: Vec::new(),
- mark: PhantomData,
- }
- }
-}
-
-impl<T: FeatureContext> Features<T> {
- /// Create a blank Features with no fetures set
- pub fn empty() -> Features<T> {
- Features {
- flags: Vec::new(),
- mark: PhantomData,
- }
- }
-
- pub(crate) fn requires_unknown_bits(&self) -> bool {
- self.flags.iter().enumerate().any(|(idx, &byte)| {
- ( idx != 0 && (byte & 0x55) != 0 ) || ( idx == 0 && (byte & 0x14) != 0 )
- })
- }
-
- pub(crate) fn supports_unknown_bits(&self) -> bool {
- self.flags.iter().enumerate().any(|(idx, &byte)| {
- ( idx != 0 && byte != 0 ) || ( idx == 0 && (byte & 0xc4) != 0 )
- })
- }
-
- /// The number of bytes required to represent the feaature flags present. This does not include
- /// the length bytes which are included in the serialized form.
- pub(crate) fn byte_count(&self) -> usize {
- self.flags.len()
- }
-
- #[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;
- }
-
- #[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<T: FeatureContextInitNode> Features<T> {
- pub(crate) fn supports_data_loss_protect(&self) -> bool {
- self.flags.len() > 0 && (self.flags[0] & 3) != 0
- }
-
- pub(crate) fn supports_upfront_shutdown_script(&self) -> bool {
- self.flags.len() > 0 && (self.flags[0] & (3 << 4)) != 0
- }
- #[cfg(test)]
- pub(crate) fn unset_upfront_shutdown_script(&mut self) {
- self.flags[0] ^= 1 << 5;
- }
-}
-
-impl Features<FeatureContextInit> {
- pub(crate) fn initial_routing_sync(&self) -> bool {
- self.flags.len() > 0 && (self.flags[0] & (1 << 3)) != 0
- }
- 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;
- }
- }
-
- /// Writes all features present up to, and including, 13.
- pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
- let len = cmp::min(2, self.flags.len());
- w.size_hint(len + 2);
- (len as u16).write(w)?;
- for i in (0..len).rev() {
- if i == 0 {
- self.flags[i].write(w)?;
- } else {
- (self.flags[i] & ((1 << (14 - 8)) - 1)).write(w)?;
- }
- }
- Ok(())
- }
-
- /// or's another InitFeatures into this one.
- pub(crate) fn or(&mut self, o: &InitFeatures) {
- let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
- self.flags.resize(total_feature_len, 0u8);
- for (feature, o_feature) in self.flags.iter_mut().zip(o.flags.iter()) {
- *feature |= *o_feature;
- }
- }
-}
-
-impl<T: FeatureContext> Writeable for Features<T> {
- fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
- w.size_hint(self.flags.len() + 2);
- (self.flags.len() as u16).write(w)?;
- for f in self.flags.iter().rev() { // We have to swap the endianness back to BE for writing
- f.write(w)?;
- }
- Ok(())
- }
-}
-
-impl<R: ::std::io::Read, T: FeatureContext> Readable<R> for Features<T> {
- fn read(r: &mut R) -> Result<Self, DecodeError> {
- let mut flags: Vec<u8> = Readable::read(r)?;
- flags.reverse(); // Swap to big-endian
- Ok(Self {
- flags,
- mark: PhantomData,
- })
- }
-}
-