Add message structs required for dual-funded channels
[rust-lightning] / lightning / src / ln / features.rs
index 1f455471a9f4fa2bf3b30b9a1ade5ac54638bb72..8ccbf4166bbe71294a64309ed4832b9364845fa9 100644 (file)
 //!     (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
 //! - `OnionMessages` - requires/supports forwarding onion messages
 //!     (see [BOLT-7](https://github.com/lightning/bolts/pull/759/files) for more information).
-//!     TODO: update link
+//     TODO: update link
 //! - `ChannelType` - node supports the channel_type field in open/accept
 //!     (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
 //! - `SCIDPrivacy` - supply channel aliases for routing
 //!     (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
+//! - `PaymentMetadata` - include additional data in invoices which is passed to recipients in the
+//!      onion.
+//!      (see [BOLT-11](https://github.com/lightning/bolts/blob/master/11-payment-encoding.md) for
+//!      more).
+//! - `ZeroConf` - supports accepting HTLCs and using channels prior to funding confirmation
+//!      (see
+//!      [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-channel_ready-message)
+//!      for more info).
 //! - `Keysend` - send funds to a node without an invoice
 //!     (see the [`Keysend` feature assignment proposal](https://github.com/lightning/bolts/issues/605#issuecomment-606679798) for more information).
+//! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
+//!     and HTLC transactions are pre-signed with zero fee (see
+//!     [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
+//!     information).
 //!
 //! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
 //! [messages]: crate::ln::msgs
@@ -65,7 +77,7 @@ use core::marker::PhantomData;
 use bitcoin::bech32;
 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
 use crate::ln::msgs::DecodeError;
-use crate::util::ser::{Readable, Writeable, Writer};
+use crate::util::ser::{Readable, WithoutLength, Writeable, Writer};
 
 mod sealed {
        use crate::prelude::*;
@@ -122,7 +134,7 @@ mod sealed {
                // Byte 1
                VariableLengthOnion | StaticRemoteKey | PaymentSecret,
                // Byte 2
-               BasicMPP | Wumbo,
+               BasicMPP | Wumbo | AnchorsZeroFeeHtlcTx,
                // Byte 3
                ShutdownAnySegwit,
                // Byte 4
@@ -138,7 +150,7 @@ mod sealed {
                // Byte 1
                VariableLengthOnion | StaticRemoteKey | PaymentSecret,
                // Byte 2
-               BasicMPP | Wumbo,
+               BasicMPP | Wumbo | AnchorsZeroFeeHtlcTx,
                // Byte 3
                ShutdownAnySegwit,
                // Byte 4
@@ -156,9 +168,26 @@ mod sealed {
                VariableLengthOnion | PaymentSecret,
                // Byte 2
                BasicMPP,
+               // Byte 3
+               ,
+               // Byte 4
+               ,
+               // Byte 5
+               ,
+               // Byte 6
+               PaymentMetadata,
        ]);
        define_context!(OfferContext, []);
        define_context!(InvoiceRequestContext, []);
+       define_context!(Bolt12InvoiceContext, [
+               // Byte 0
+               ,
+               // Byte 1
+               ,
+               // Byte 2
+               BasicMPP,
+       ]);
+       define_context!(BlindedHopContext, []);
        // This isn't a "real" feature context, and is only used in the channel_type field in an
        // `OpenChannel` message.
        define_context!(ChannelTypeContext, [
@@ -167,7 +196,7 @@ mod sealed {
                // Byte 1
                StaticRemoteKey,
                // Byte 2
-               ,
+               AnchorsZeroFeeHtlcTx,
                // Byte 3
                ,
                // Byte 4
@@ -246,6 +275,7 @@ mod sealed {
                                        }
 
                                        flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
+                                       flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
                                }
 
                                /// Sets the feature's optional (odd) bit in the given flags.
@@ -342,12 +372,15 @@ mod sealed {
        define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
                "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required,
                supports_payment_secret, requires_payment_secret);
-       define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
+       define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext, Bolt12InvoiceContext],
                "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
                supports_basic_mpp, requires_basic_mpp);
        define_feature!(19, Wumbo, [InitContext, NodeContext],
                "Feature flags for `option_support_large_channel` (aka wumbo channels).", set_wumbo_optional, set_wumbo_required,
                supports_wumbo, requires_wumbo);
+       define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
+               "Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
+               set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
        define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
                "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
                set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
@@ -360,16 +393,20 @@ mod sealed {
        define_feature!(47, SCIDPrivacy, [InitContext, NodeContext, ChannelTypeContext],
                "Feature flags for only forwarding with SCID aliasing. Called `option_scid_alias` in the BOLTs",
                set_scid_privacy_optional, set_scid_privacy_required, supports_scid_privacy, requires_scid_privacy);
+       define_feature!(49, PaymentMetadata, [InvoiceContext],
+               "Feature flags for payment metadata in invoices.", set_payment_metadata_optional,
+               set_payment_metadata_required, supports_payment_metadata, requires_payment_metadata);
        define_feature!(51, ZeroConf, [InitContext, NodeContext, ChannelTypeContext],
                "Feature flags for accepting channels with zero confirmations. Called `option_zeroconf` in the BOLTs",
                set_zero_conf_optional, set_zero_conf_required, supports_zero_conf, requires_zero_conf);
        define_feature!(55, Keysend, [NodeContext],
                "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
                supports_keysend, requires_keysend);
+       // Note: update the module-level docs when a new feature bit is added!
 
        #[cfg(test)]
        define_feature!(123456789, UnknownFeature,
-               [NodeContext, ChannelContext, InvoiceContext, OfferContext, InvoiceRequestContext],
+               [NodeContext, ChannelContext, InvoiceContext, OfferContext, InvoiceRequestContext, Bolt12InvoiceContext, BlindedHopContext],
                "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);
 }
@@ -377,7 +414,7 @@ mod sealed {
 /// 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
+/// This is not exported to bindings users as we map the concrete feature types below directly instead
 #[derive(Eq)]
 pub struct Features<T: sealed::Context> {
        /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
@@ -432,6 +469,10 @@ pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
 pub type OfferFeatures = Features<sealed::OfferContext>;
 /// Features used within an `invoice_request`.
 pub type InvoiceRequestFeatures = Features<sealed::InvoiceRequestContext>;
+/// Features used within an `invoice`.
+pub type Bolt12InvoiceFeatures = Features<sealed::Bolt12InvoiceContext>;
+/// Features used within BOLT 4 encrypted_data_tlv and BOLT 12 blinded_payinfo
+pub type BlindedHopFeatures = Features<sealed::BlindedHopContext>;
 
 /// Features used within the channel_type field in an OpenChannel message.
 ///
@@ -492,10 +533,10 @@ impl InvoiceFeatures {
 }
 
 impl ChannelTypeFeatures {
-       /// Constructs the implicit channel type based on the common supported types between us and our
-       /// counterparty
-       pub(crate) fn from_counterparty_init(counterparty_init: &InitFeatures) -> Self {
-               let mut ret = counterparty_init.to_context_internal();
+       // Maps the relevant `InitFeatures` to `ChannelTypeFeatures`. Any unknown features to
+       // `ChannelTypeFeatures` are not included in the result.
+       pub(crate) fn from_init(init: &InitFeatures) -> Self {
+               let mut ret = init.to_context_internal();
                // ChannelTypeFeatures must only contain required bits, so we OR the required forms of all
                // optional bits and then AND out the optional ones.
                for byte in ret.flags.iter_mut() {
@@ -602,7 +643,8 @@ impl<T: sealed::Context> Features<T> {
 
        /// 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
+       ///
+       /// This is not exported to bindings users as we don't support export across multiple T
        pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
                Features {
                        flags,
@@ -665,6 +707,24 @@ impl<T: sealed::Context> Features<T> {
                        (byte & unknown_features) != 0
                })
        }
+
+       // Returns true if the features within `self` are a subset of the features within `other`.
+       pub(crate) fn is_subset(&self, other: &Self) -> bool {
+               for (idx, byte) in self.flags.iter().enumerate() {
+                       if let Some(other_byte) = other.flags.get(idx) {
+                               if byte & other_byte != *byte {
+                                       // `self` has bits set that `other` doesn't.
+                                       return false;
+                               }
+                       } else {
+                               if *byte > 0 {
+                                       // `self` has a non-zero byte that `other` doesn't.
+                                       return false;
+                               }
+                       }
+               }
+               true
+       }
 }
 
 impl<T: sealed::UpfrontShutdownScript> Features<T> {
@@ -691,6 +751,18 @@ impl<T: sealed::Wumbo> Features<T> {
        }
 }
 
+impl<T: sealed::SCIDPrivacy> Features<T> {
+       pub(crate) fn clear_scid_privacy(&mut self) {
+               <T as sealed::SCIDPrivacy>::clear_bits(&mut self.flags);
+       }
+}
+
+impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
+       pub(crate) fn clear_anchors_zero_fee_htlc_tx(&mut self) {
+               <T as sealed::AnchorsZeroFeeHtlcTx>::clear_bits(&mut self.flags);
+       }
+}
+
 #[cfg(test)]
 impl<T: sealed::UnknownFeature> Features<T> {
        pub(crate) fn unknown() -> Self {
@@ -719,32 +791,47 @@ impl_feature_len_prefixed_write!(InitFeatures);
 impl_feature_len_prefixed_write!(ChannelFeatures);
 impl_feature_len_prefixed_write!(NodeFeatures);
 impl_feature_len_prefixed_write!(InvoiceFeatures);
+impl_feature_len_prefixed_write!(BlindedHopFeatures);
 
 // 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)
+                               WithoutLength(self).write(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))
+                               Ok(WithoutLength::<Self>::read(r)?.0)
                        }
                }
        }
 }
 
 impl_feature_tlv_write!(ChannelTypeFeatures);
-impl_feature_tlv_write!(OfferFeatures);
-impl_feature_tlv_write!(InvoiceRequestFeatures);
+
+// Some features may appear both in a TLV record and as part of a TLV subtype sequence. The latter
+// requires a length but the former does not.
+
+impl<T: sealed::Context> Writeable for WithoutLength<&Features<T>> {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               self.0.write_be(w)
+       }
+}
+
+impl<T: sealed::Context> Readable for WithoutLength<Features<T>> {
+       fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let v = io_extras::read_to_end(r)?;
+               Ok(WithoutLength(Features::<T>::from_be_bytes(v)))
+       }
+}
 
 #[cfg(test)]
 mod tests {
-       use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, InvoiceFeatures, NodeFeatures, sealed};
+       use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, InvoiceFeatures, NodeFeatures, OfferFeatures, sealed};
        use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
+       use crate::util::ser::{Readable, WithoutLength, Writeable};
 
        #[test]
        fn sanity_test_unknown_bits() {
@@ -769,7 +856,7 @@ mod tests {
                // Set a bunch of features we use, plus initial_routing_sync_required (which shouldn't get
                // converted as it's only relevant in an init context).
                init_features.set_initial_routing_sync_required();
-               init_features.set_data_loss_protect_optional();
+               init_features.set_data_loss_protect_required();
                init_features.set_variable_length_onion_required();
                init_features.set_static_remote_key_required();
                init_features.set_payment_secret_required();
@@ -780,6 +867,7 @@ mod tests {
                init_features.set_channel_type_optional();
                init_features.set_scid_privacy_optional();
                init_features.set_zero_conf_optional();
+               init_features.set_anchors_zero_fee_htlc_tx_optional();
 
                assert!(init_features.initial_routing_sync());
                assert!(!init_features.supports_upfront_shutdown_script());
@@ -788,7 +876,7 @@ mod tests {
                let node_features: NodeFeatures = init_features.to_context();
                {
                        // Check that the flags are as expected:
-                       // - option_data_loss_protect
+                       // - option_data_loss_protect (req)
                        // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
                        // - basic_mpp | wumbo
                        // - opt_shutdown_anysegwit
@@ -796,9 +884,9 @@ mod tests {
                        // - option_channel_type | option_scid_alias
                        // - option_zeroconf
                        assert_eq!(node_features.flags.len(), 7);
-                       assert_eq!(node_features.flags[0], 0b00000010);
+                       assert_eq!(node_features.flags[0], 0b00000001);
                        assert_eq!(node_features.flags[1], 0b01010001);
-                       assert_eq!(node_features.flags[2], 0b00001010);
+                       assert_eq!(node_features.flags[2], 0b10001010);
                        assert_eq!(node_features.flags[3], 0b00001000);
                        assert_eq!(node_features.flags[4], 0b10000000);
                        assert_eq!(node_features.flags[5], 0b10100000);
@@ -818,13 +906,13 @@ mod tests {
        #[test]
        fn convert_to_context_with_unknown_flags() {
                // Ensure the `from` context has fewer known feature bytes than the `to` context.
-               assert!(<sealed::InvoiceContext as sealed::Context>::KNOWN_FEATURE_MASK.len() <
-                       <sealed::NodeContext as sealed::Context>::KNOWN_FEATURE_MASK.len());
-               let mut invoice_features = InvoiceFeatures::empty();
-               invoice_features.set_unknown_feature_optional();
-               assert!(invoice_features.supports_unknown_bits());
-               let node_features: NodeFeatures = invoice_features.to_context();
-               assert!(!node_features.supports_unknown_bits());
+               assert!(<sealed::ChannelContext as sealed::Context>::KNOWN_FEATURE_MASK.len() <
+                       <sealed::InvoiceContext as sealed::Context>::KNOWN_FEATURE_MASK.len());
+               let mut channel_features = ChannelFeatures::empty();
+               channel_features.set_unknown_feature_optional();
+               assert!(channel_features.supports_unknown_bits());
+               let invoice_features: InvoiceFeatures = channel_features.to_context_internal();
+               assert!(!invoice_features.supports_unknown_bits());
        }
 
        #[test]
@@ -838,6 +926,20 @@ mod tests {
                assert!(features.supports_payment_secret());
        }
 
+       #[test]
+       fn encodes_features_without_length() {
+               let features = OfferFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
+               assert_eq!(features.flags.len(), 8);
+
+               let mut serialized_features = Vec::new();
+               WithoutLength(&features).write(&mut serialized_features).unwrap();
+               assert_eq!(serialized_features.len(), 8);
+
+               let deserialized_features =
+                       WithoutLength::<OfferFeatures>::read(&mut &serialized_features[..]).unwrap().0;
+               assert_eq!(features, deserialized_features);
+       }
+
        #[test]
        fn invoice_features_encoding() {
                let features_as_u5s = vec![
@@ -875,7 +977,7 @@ mod tests {
                // required-StaticRemoteKey ChannelTypeFeatures.
                let mut init_features = InitFeatures::empty();
                init_features.set_static_remote_key_optional();
-               let converted_features = ChannelTypeFeatures::from_counterparty_init(&init_features);
+               let converted_features = ChannelTypeFeatures::from_init(&init_features);
                assert_eq!(converted_features, ChannelTypeFeatures::only_static_remote_key());
                assert!(!converted_features.supports_any_optional_bits());
                assert!(converted_features.requires_static_remote_key());