1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Feature flag definitions for the Lightning protocol according to [BOLT #9].
12 //! Lightning nodes advertise a supported set of operation through feature flags. Features are
13 //! applicable for a specific context as indicated in some [messages]. [`Features`] encapsulates
14 //! behavior for specifying and checking feature flags for a particular context. Each feature is
15 //! defined internally by a trait specifying the corresponding flags (i.e., even and odd bits).
17 //! Whether a feature is considered "known" or "unknown" is relative to the implementation, whereas
18 //! the term "supports" is used in reference to a particular set of [`Features`]. That is, a node
19 //! supports a feature if it advertises the feature (as either required or optional) to its peers.
20 //! And the implementation can interpret a feature if the feature is known to it.
22 //! [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
23 //! [messages]: crate::ln::msgs
27 use core::marker::PhantomData;
30 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
31 use ln::msgs::DecodeError;
32 use util::ser::{Readable, Writeable, Writer};
36 use ln::features::Features;
38 /// The context in which [`Features`] are applicable. Defines which features are required and
39 /// which are optional for the context.
41 /// Features that are known to the implementation, where a required feature is indicated by
42 /// its even bit and an optional feature is indicated by its odd bit.
43 const KNOWN_FEATURE_FLAGS: &'static [u8];
45 /// Bitmask for selecting features that are known to the implementation, regardless of
46 /// whether each feature is required or optional.
47 const KNOWN_FEATURE_MASK: &'static [u8];
50 /// Defines a [`Context`] by stating which features it requires and which are optional. Features
51 /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
52 /// feature identifiers.
53 macro_rules! define_context {
55 required_features: [$( $( $required_feature: ident )|*, )*],
56 optional_features: [$( $( $optional_feature: ident )|*, )*],
58 #[derive(Eq, PartialEq)]
59 pub struct $context {}
61 impl Context for $context {
62 const KNOWN_FEATURE_FLAGS: &'static [u8] = &[
63 // For each byte, use bitwise-OR to compute the applicable flags for known
64 // required features `r_i` and optional features `o_j` for all `i` and `j` such
65 // that the following slice is formed:
68 // `r_0` | `r_1` | ... | `o_0` | `o_1` | ...,
73 <Self as $required_feature>::REQUIRED_MASK)*
75 <Self as $optional_feature>::OPTIONAL_MASK)*,
79 const KNOWN_FEATURE_MASK: &'static [u8] = &[
80 // Similar as above, but set both flags for each feature regardless of whether
81 // the feature is required or optional.
84 <Self as $required_feature>::REQUIRED_MASK |
85 <Self as $required_feature>::OPTIONAL_MASK)*
87 <Self as $optional_feature>::REQUIRED_MASK |
88 <Self as $optional_feature>::OPTIONAL_MASK)*,
95 define_context!(InitContext {
100 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
108 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
117 define_context!(NodeContext {
122 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
136 DataLossProtect | UpfrontShutdownScript | GossipQueries,
151 define_context!(ChannelContext {
152 required_features: [],
153 optional_features: [],
155 define_context!(InvoiceContext {
160 VariableLengthOnion | PaymentSecret,
174 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
175 /// useful for manipulating feature flags.
176 macro_rules! define_feature {
177 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
178 $required_setter: ident) => {
181 /// See [BOLT #9] for details.
183 /// [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
184 pub trait $feature: Context {
185 /// The bit used to signify that the feature is required.
186 const EVEN_BIT: usize = $odd_bit - 1;
188 /// The bit used to signify that the feature is optional.
189 const ODD_BIT: usize = $odd_bit;
191 /// Assertion that [`EVEN_BIT`] is actually even.
193 /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
194 const ASSERT_EVEN_BIT_PARITY: usize;
196 /// Assertion that [`ODD_BIT`] is actually odd.
198 /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
199 const ASSERT_ODD_BIT_PARITY: usize;
201 /// The byte where the feature is set.
202 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
204 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
206 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
207 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
209 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
211 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
212 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
214 /// Returns whether the feature is required by the given flags.
216 fn requires_feature(flags: &Vec<u8>) -> bool {
217 flags.len() > Self::BYTE_OFFSET &&
218 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
221 /// Returns whether the feature is supported by the given flags.
223 fn supports_feature(flags: &Vec<u8>) -> bool {
224 flags.len() > Self::BYTE_OFFSET &&
225 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
228 /// Sets the feature's required (even) bit in the given flags.
230 fn set_required_bit(flags: &mut Vec<u8>) {
231 if flags.len() <= Self::BYTE_OFFSET {
232 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
235 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
238 /// Sets the feature's optional (odd) bit in the given flags.
240 fn set_optional_bit(flags: &mut Vec<u8>) {
241 if flags.len() <= Self::BYTE_OFFSET {
242 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
245 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
248 /// Clears the feature's required (even) and optional (odd) bits from the given
251 fn clear_bits(flags: &mut Vec<u8>) {
252 if flags.len() > Self::BYTE_OFFSET {
253 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
254 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
257 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
258 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
259 flags.resize(size, 0u8);
263 impl <T: $feature> Features<T> {
264 /// Set this feature as optional.
265 pub fn $optional_setter(mut self) -> Self {
266 <T as $feature>::set_optional_bit(&mut self.flags);
270 /// Set this feature as required.
271 pub fn $required_setter(mut self) -> Self {
272 <T as $feature>::set_required_bit(&mut self.flags);
278 impl $feature for $context {
280 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
283 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
290 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
291 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
292 set_data_loss_protect_required);
293 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
294 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
295 set_initial_routing_sync_optional, set_initial_routing_sync_required);
296 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
297 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
298 set_upfront_shutdown_script_required);
299 define_feature!(7, GossipQueries, [InitContext, NodeContext],
300 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required);
301 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext],
302 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
303 set_variable_length_onion_required);
304 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext],
305 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
306 set_static_remote_key_required);
307 define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
308 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required);
309 define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
310 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required);
311 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
312 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
313 set_shutdown_any_segwit_required);
314 define_feature!(55, Keysend, [NodeContext],
315 "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required);
318 define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
319 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
320 set_unknown_feature_required);
323 /// Tracks the set of features which a node implements, templated by the context in which it
326 /// (C-not exported) as we map the concrete feature types below directly instead
328 pub struct Features<T: sealed::Context> {
329 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
331 mark: PhantomData<T>,
334 impl<T: sealed::Context> Clone for Features<T> {
335 fn clone(&self) -> Self {
337 flags: self.flags.clone(),
342 impl<T: sealed::Context> PartialEq for Features<T> {
343 fn eq(&self, o: &Self) -> bool {
344 self.flags.eq(&o.flags)
347 impl<T: sealed::Context> fmt::Debug for Features<T> {
348 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
353 /// Features used within an `init` message.
354 pub type InitFeatures = Features<sealed::InitContext>;
355 /// Features used within a `node_announcement` message.
356 pub type NodeFeatures = Features<sealed::NodeContext>;
357 /// Features used within a `channel_announcement` message.
358 pub type ChannelFeatures = Features<sealed::ChannelContext>;
359 /// Features used within an invoice.
360 pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
363 /// Writes all features present up to, and including, 13.
364 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
365 let len = cmp::min(2, self.flags.len());
366 w.size_hint(len + 2);
367 (len as u16).write(w)?;
368 for i in (0..len).rev() {
370 self.flags[i].write(w)?;
372 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
373 // up-to-and-including-bit-5, 0-indexed, on this byte:
374 (self.flags[i] & 0b00_11_11_11).write(w)?;
380 /// or's another InitFeatures into this one.
381 pub(crate) fn or(mut self, o: InitFeatures) -> InitFeatures {
382 let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
383 self.flags.resize(total_feature_len, 0u8);
384 for (byte, o_byte) in self.flags.iter_mut().zip(o.flags.iter()) {
390 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
391 /// are included in the result.
392 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
393 self.to_context_internal()
397 impl InvoiceFeatures {
398 /// Converts `InvoiceFeatures` to `Features<C>`. Only known `InvoiceFeatures` relevant to
399 /// context `C` are included in the result.
400 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
401 self.to_context_internal()
405 impl ToBase32 for InvoiceFeatures {
406 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
407 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
408 // minus one before dividing
409 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
410 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
411 for (byte_idx, byte) in self.flags.iter().enumerate() {
412 let bit_pos_from_left_0_indexed = byte_idx * 8;
413 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
414 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
415 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
416 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
417 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
419 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
420 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
423 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
424 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
427 // Trim the highest feature bits.
428 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
431 writer.write(&res_u5s)
435 impl Base32Len for InvoiceFeatures {
436 fn base32_len(&self) -> usize {
437 self.to_base32().len()
441 impl FromBase32 for InvoiceFeatures {
442 type Err = bech32::Error;
444 fn from_base32(field_data: &[u5]) -> Result<InvoiceFeatures, bech32::Error> {
445 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
446 // minus one before dividing
447 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
448 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
449 for (u5_idx, chunk) in field_data.iter().enumerate() {
450 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
451 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
452 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
453 let chunk_u16 = chunk.to_u8() as u16;
454 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
455 if new_byte_idx != length_bytes - 1 {
456 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
459 // Trim the highest feature bits.
460 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
463 Ok(InvoiceFeatures::from_le_bytes(res_bytes))
467 impl<T: sealed::Context> Features<T> {
468 /// Create a blank Features with no features set
469 pub fn empty() -> Self {
476 /// Creates a Features with the bits set which are known by the implementation
477 pub fn known() -> Self {
479 flags: T::KNOWN_FEATURE_FLAGS.to_vec(),
484 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
485 /// included in the result.
486 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
487 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
488 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
489 let mut flags = Vec::new();
490 for (i, byte) in self.flags.iter().enumerate() {
491 if i < from_byte_count && i < to_byte_count {
492 let from_known_features = T::KNOWN_FEATURE_MASK[i];
493 let to_known_features = C::KNOWN_FEATURE_MASK[i];
494 flags.push(byte & from_known_features & to_known_features);
497 Features::<C> { flags, mark: PhantomData, }
500 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
501 /// most on-the-wire encodings.
502 /// (C-not exported) as we don't support export across multiple T
503 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
511 /// Gets the underlying flags set, in LE.
512 pub fn le_flags(&self) -> &Vec<u8> {
516 pub(crate) fn requires_unknown_bits(&self) -> bool {
517 // Bitwise AND-ing with all even bits set except for known features will select required
519 let byte_count = T::KNOWN_FEATURE_MASK.len();
520 self.flags.iter().enumerate().any(|(i, &byte)| {
521 let required_features = 0b01_01_01_01;
522 let unknown_features = if i < byte_count {
523 !T::KNOWN_FEATURE_MASK[i]
527 (byte & (required_features & unknown_features)) != 0
531 pub(crate) fn supports_unknown_bits(&self) -> bool {
532 // Bitwise AND-ing with all even and odd bits set except for known features will select
533 // both required and optional unknown features.
534 let byte_count = T::KNOWN_FEATURE_MASK.len();
535 self.flags.iter().enumerate().any(|(i, &byte)| {
536 let unknown_features = if i < byte_count {
537 !T::KNOWN_FEATURE_MASK[i]
541 (byte & unknown_features) != 0
545 /// The number of bytes required to represent the feature flags present. This does not include
546 /// the length bytes which are included in the serialized form.
547 pub(crate) fn byte_count(&self) -> usize {
552 impl<T: sealed::DataLossProtect> Features<T> {
554 pub(crate) fn requires_data_loss_protect(&self) -> bool {
555 <T as sealed::DataLossProtect>::requires_feature(&self.flags)
557 pub(crate) fn supports_data_loss_protect(&self) -> bool {
558 <T as sealed::DataLossProtect>::supports_feature(&self.flags)
562 impl<T: sealed::UpfrontShutdownScript> Features<T> {
564 pub(crate) fn requires_upfront_shutdown_script(&self) -> bool {
565 <T as sealed::UpfrontShutdownScript>::requires_feature(&self.flags)
567 pub(crate) fn supports_upfront_shutdown_script(&self) -> bool {
568 <T as sealed::UpfrontShutdownScript>::supports_feature(&self.flags)
571 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
572 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
578 impl<T: sealed::GossipQueries> Features<T> {
580 pub(crate) fn requires_gossip_queries(&self) -> bool {
581 <T as sealed::GossipQueries>::requires_feature(&self.flags)
583 pub(crate) fn supports_gossip_queries(&self) -> bool {
584 <T as sealed::GossipQueries>::supports_feature(&self.flags)
587 pub(crate) fn clear_gossip_queries(mut self) -> Self {
588 <T as sealed::GossipQueries>::clear_bits(&mut self.flags);
593 impl<T: sealed::VariableLengthOnion> Features<T> {
595 pub(crate) fn requires_variable_length_onion(&self) -> bool {
596 <T as sealed::VariableLengthOnion>::requires_feature(&self.flags)
598 pub(crate) fn supports_variable_length_onion(&self) -> bool {
599 <T as sealed::VariableLengthOnion>::supports_feature(&self.flags)
603 impl<T: sealed::StaticRemoteKey> Features<T> {
604 pub(crate) fn supports_static_remote_key(&self) -> bool {
605 <T as sealed::StaticRemoteKey>::supports_feature(&self.flags)
608 pub(crate) fn requires_static_remote_key(&self) -> bool {
609 <T as sealed::StaticRemoteKey>::requires_feature(&self.flags)
613 impl<T: sealed::InitialRoutingSync> Features<T> {
614 pub(crate) fn initial_routing_sync(&self) -> bool {
615 <T as sealed::InitialRoutingSync>::supports_feature(&self.flags)
617 // We are no longer setting initial_routing_sync now that gossip_queries
618 // is enabled. This feature is ignored by a peer when gossip_queries has
621 pub(crate) fn clear_initial_routing_sync(&mut self) {
622 <T as sealed::InitialRoutingSync>::clear_bits(&mut self.flags)
626 impl<T: sealed::PaymentSecret> Features<T> {
628 pub(crate) fn requires_payment_secret(&self) -> bool {
629 <T as sealed::PaymentSecret>::requires_feature(&self.flags)
631 /// Returns whether the `payment_secret` feature is supported.
632 pub fn supports_payment_secret(&self) -> bool {
633 <T as sealed::PaymentSecret>::supports_feature(&self.flags)
637 impl<T: sealed::BasicMPP> Features<T> {
639 pub(crate) fn requires_basic_mpp(&self) -> bool {
640 <T as sealed::BasicMPP>::requires_feature(&self.flags)
642 // We currently never test for this since we don't actually *generate* multipath routes.
643 pub(crate) fn supports_basic_mpp(&self) -> bool {
644 <T as sealed::BasicMPP>::supports_feature(&self.flags)
648 impl<T: sealed::ShutdownAnySegwit> Features<T> {
649 pub(crate) fn supports_shutdown_anysegwit(&self) -> bool {
650 <T as sealed::ShutdownAnySegwit>::supports_feature(&self.flags)
653 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
654 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
659 impl<T: sealed::Context> Writeable for Features<T> {
660 fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
661 w.size_hint(self.flags.len() + 2);
662 (self.flags.len() as u16).write(w)?;
663 for f in self.flags.iter().rev() { // Swap back to big-endian
670 impl<T: sealed::Context> Readable for Features<T> {
671 fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
672 let mut flags: Vec<u8> = Readable::read(r)?;
673 flags.reverse(); // Swap to little-endian
683 use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
684 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
687 fn sanity_test_known_features() {
688 assert!(!ChannelFeatures::known().requires_unknown_bits());
689 assert!(!ChannelFeatures::known().supports_unknown_bits());
690 assert!(!InitFeatures::known().requires_unknown_bits());
691 assert!(!InitFeatures::known().supports_unknown_bits());
692 assert!(!NodeFeatures::known().requires_unknown_bits());
693 assert!(!NodeFeatures::known().supports_unknown_bits());
695 assert!(InitFeatures::known().supports_upfront_shutdown_script());
696 assert!(NodeFeatures::known().supports_upfront_shutdown_script());
697 assert!(!InitFeatures::known().requires_upfront_shutdown_script());
698 assert!(!NodeFeatures::known().requires_upfront_shutdown_script());
700 assert!(InitFeatures::known().supports_gossip_queries());
701 assert!(NodeFeatures::known().supports_gossip_queries());
702 assert!(!InitFeatures::known().requires_gossip_queries());
703 assert!(!NodeFeatures::known().requires_gossip_queries());
705 assert!(InitFeatures::known().supports_data_loss_protect());
706 assert!(NodeFeatures::known().supports_data_loss_protect());
707 assert!(!InitFeatures::known().requires_data_loss_protect());
708 assert!(!NodeFeatures::known().requires_data_loss_protect());
710 assert!(InitFeatures::known().supports_variable_length_onion());
711 assert!(NodeFeatures::known().supports_variable_length_onion());
712 assert!(InvoiceFeatures::known().supports_variable_length_onion());
713 assert!(InitFeatures::known().requires_variable_length_onion());
714 assert!(NodeFeatures::known().requires_variable_length_onion());
715 assert!(InvoiceFeatures::known().requires_variable_length_onion());
717 assert!(InitFeatures::known().supports_static_remote_key());
718 assert!(NodeFeatures::known().supports_static_remote_key());
719 assert!(InitFeatures::known().requires_static_remote_key());
720 assert!(NodeFeatures::known().requires_static_remote_key());
722 assert!(InitFeatures::known().supports_payment_secret());
723 assert!(NodeFeatures::known().supports_payment_secret());
724 assert!(InvoiceFeatures::known().supports_payment_secret());
725 assert!(InitFeatures::known().requires_payment_secret());
726 assert!(NodeFeatures::known().requires_payment_secret());
727 assert!(InvoiceFeatures::known().requires_payment_secret());
729 assert!(InitFeatures::known().supports_basic_mpp());
730 assert!(NodeFeatures::known().supports_basic_mpp());
731 assert!(InvoiceFeatures::known().supports_basic_mpp());
732 assert!(!InitFeatures::known().requires_basic_mpp());
733 assert!(!NodeFeatures::known().requires_basic_mpp());
734 assert!(!InvoiceFeatures::known().requires_basic_mpp());
736 assert!(InitFeatures::known().supports_shutdown_anysegwit());
737 assert!(NodeFeatures::known().supports_shutdown_anysegwit());
739 let mut init_features = InitFeatures::known();
740 assert!(init_features.initial_routing_sync());
741 init_features.clear_initial_routing_sync();
742 assert!(!init_features.initial_routing_sync());
746 fn sanity_test_unknown_bits() {
747 let features = ChannelFeatures::empty();
748 assert!(!features.requires_unknown_bits());
749 assert!(!features.supports_unknown_bits());
751 let features = ChannelFeatures::empty().set_unknown_feature_required();
752 assert!(features.requires_unknown_bits());
753 assert!(features.supports_unknown_bits());
755 let features = ChannelFeatures::empty().set_unknown_feature_optional();
756 assert!(!features.requires_unknown_bits());
757 assert!(features.supports_unknown_bits());
761 fn convert_to_context_with_relevant_flags() {
762 let init_features = InitFeatures::known().clear_upfront_shutdown_script().clear_gossip_queries();
763 assert!(init_features.initial_routing_sync());
764 assert!(!init_features.supports_upfront_shutdown_script());
765 assert!(!init_features.supports_gossip_queries());
767 let node_features: NodeFeatures = init_features.to_context();
769 // Check that the flags are as expected:
770 // - option_data_loss_protect
771 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
773 // - opt_shutdown_anysegwit
774 assert_eq!(node_features.flags.len(), 4);
775 assert_eq!(node_features.flags[0], 0b00000010);
776 assert_eq!(node_features.flags[1], 0b01010001);
777 assert_eq!(node_features.flags[2], 0b00000010);
778 assert_eq!(node_features.flags[3], 0b00001000);
781 // Check that cleared flags are kept blank when converting back:
782 // - initial_routing_sync was not applicable to NodeContext
783 // - upfront_shutdown_script was cleared before converting
784 // - gossip_queries was cleared before converting
785 let features: InitFeatures = node_features.to_context_internal();
786 assert!(!features.initial_routing_sync());
787 assert!(!features.supports_upfront_shutdown_script());
788 assert!(!init_features.supports_gossip_queries());
792 fn convert_to_context_with_unknown_flags() {
793 // Ensure the `from` context has fewer known feature bytes than the `to` context.
794 assert!(InvoiceFeatures::known().byte_count() < NodeFeatures::known().byte_count());
795 let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional();
796 assert!(invoice_features.supports_unknown_bits());
797 let node_features: NodeFeatures = invoice_features.to_context();
798 assert!(!node_features.supports_unknown_bits());
802 fn set_feature_bits() {
803 let features = InvoiceFeatures::empty()
804 .set_basic_mpp_optional()
805 .set_payment_secret_required();
806 assert!(features.supports_basic_mpp());
807 assert!(!features.requires_basic_mpp());
808 assert!(features.requires_payment_secret());
809 assert!(features.supports_payment_secret());
813 fn invoice_features_encoding() {
814 let features_as_u5s = vec![
815 u5::try_from_u8(6).unwrap(),
816 u5::try_from_u8(10).unwrap(),
817 u5::try_from_u8(25).unwrap(),
818 u5::try_from_u8(1).unwrap(),
819 u5::try_from_u8(10).unwrap(),
820 u5::try_from_u8(0).unwrap(),
821 u5::try_from_u8(20).unwrap(),
822 u5::try_from_u8(2).unwrap(),
823 u5::try_from_u8(0).unwrap(),
824 u5::try_from_u8(6).unwrap(),
825 u5::try_from_u8(0).unwrap(),
826 u5::try_from_u8(16).unwrap(),
827 u5::try_from_u8(1).unwrap(),
829 let features = InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
831 // Test length calculation.
832 assert_eq!(features.base32_len(), 13);
834 // Test serialization.
835 let features_serialized = features.to_base32();
836 assert_eq!(features_as_u5s, features_serialized);
838 // Test deserialization.
839 let features_deserialized = InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
840 assert_eq!(features, features_deserialized);