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 $optional_feature>::OPTIONAL_MASK)*,
95 define_context!(InitContext {
100 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
108 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
117 define_context!(NodeContext {
122 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
130 DataLossProtect | UpfrontShutdownScript | GossipQueries,
139 define_context!(ChannelContext {
140 required_features: [],
141 optional_features: [],
143 define_context!(InvoiceContext {
148 VariableLengthOnion | PaymentSecret,
162 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
163 /// useful for manipulating feature flags.
164 macro_rules! define_feature {
165 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
166 $required_setter: ident) => {
169 /// See [BOLT #9] for details.
171 /// [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
172 pub trait $feature: Context {
173 /// The bit used to signify that the feature is required.
174 const EVEN_BIT: usize = $odd_bit - 1;
176 /// The bit used to signify that the feature is optional.
177 const ODD_BIT: usize = $odd_bit;
179 /// Assertion that [`EVEN_BIT`] is actually even.
181 /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
182 const ASSERT_EVEN_BIT_PARITY: usize;
184 /// Assertion that [`ODD_BIT`] is actually odd.
186 /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
187 const ASSERT_ODD_BIT_PARITY: usize;
189 /// The byte where the feature is set.
190 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
192 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
194 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
195 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
197 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
199 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
200 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
202 /// Returns whether the feature is required by the given flags.
204 fn requires_feature(flags: &Vec<u8>) -> bool {
205 flags.len() > Self::BYTE_OFFSET &&
206 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
209 /// Returns whether the feature is supported by the given flags.
211 fn supports_feature(flags: &Vec<u8>) -> bool {
212 flags.len() > Self::BYTE_OFFSET &&
213 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
216 /// Sets the feature's required (even) bit in the given flags.
218 fn set_required_bit(flags: &mut Vec<u8>) {
219 if flags.len() <= Self::BYTE_OFFSET {
220 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
223 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
226 /// Sets the feature's optional (odd) bit in the given flags.
228 fn set_optional_bit(flags: &mut Vec<u8>) {
229 if flags.len() <= Self::BYTE_OFFSET {
230 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
233 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
236 /// Clears the feature's required (even) and optional (odd) bits from the given
239 fn clear_bits(flags: &mut Vec<u8>) {
240 if flags.len() > Self::BYTE_OFFSET {
241 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
242 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
245 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
246 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
247 flags.resize(size, 0u8);
251 impl <T: $feature> Features<T> {
252 /// Set this feature as optional.
253 pub fn $optional_setter(mut self) -> Self {
254 <T as $feature>::set_optional_bit(&mut self.flags);
258 /// Set this feature as required.
259 pub fn $required_setter(mut self) -> Self {
260 <T as $feature>::set_required_bit(&mut self.flags);
266 impl $feature for $context {
268 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
271 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
278 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
279 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
280 set_data_loss_protect_required);
281 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
282 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
283 set_initial_routing_sync_optional, set_initial_routing_sync_required);
284 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
285 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
286 set_upfront_shutdown_script_required);
287 define_feature!(7, GossipQueries, [InitContext, NodeContext],
288 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required);
289 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext],
290 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
291 set_variable_length_onion_required);
292 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext],
293 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
294 set_static_remote_key_required);
295 define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
296 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required);
297 define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
298 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required);
299 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
300 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
301 set_shutdown_any_segwit_required);
304 define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
305 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
306 set_unknown_feature_required);
309 /// Tracks the set of features which a node implements, templated by the context in which it
312 /// (C-not exported) as we map the concrete feature types below directly instead
314 pub struct Features<T: sealed::Context> {
315 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
317 mark: PhantomData<T>,
320 impl<T: sealed::Context> Clone for Features<T> {
321 fn clone(&self) -> Self {
323 flags: self.flags.clone(),
328 impl<T: sealed::Context> PartialEq for Features<T> {
329 fn eq(&self, o: &Self) -> bool {
330 self.flags.eq(&o.flags)
333 impl<T: sealed::Context> fmt::Debug for Features<T> {
334 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
339 /// Features used within an `init` message.
340 pub type InitFeatures = Features<sealed::InitContext>;
341 /// Features used within a `node_announcement` message.
342 pub type NodeFeatures = Features<sealed::NodeContext>;
343 /// Features used within a `channel_announcement` message.
344 pub type ChannelFeatures = Features<sealed::ChannelContext>;
345 /// Features used within an invoice.
346 pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
349 /// Writes all features present up to, and including, 13.
350 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
351 let len = cmp::min(2, self.flags.len());
352 w.size_hint(len + 2);
353 (len as u16).write(w)?;
354 for i in (0..len).rev() {
356 self.flags[i].write(w)?;
358 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
359 // up-to-and-including-bit-5, 0-indexed, on this byte:
360 (self.flags[i] & 0b00_11_11_11).write(w)?;
366 /// or's another InitFeatures into this one.
367 pub(crate) fn or(mut self, o: InitFeatures) -> InitFeatures {
368 let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
369 self.flags.resize(total_feature_len, 0u8);
370 for (byte, o_byte) in self.flags.iter_mut().zip(o.flags.iter()) {
376 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
377 /// are included in the result.
378 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
379 self.to_context_internal()
383 impl InvoiceFeatures {
384 /// Converts `InvoiceFeatures` to `Features<C>`. Only known `InvoiceFeatures` relevant to
385 /// context `C` are included in the result.
386 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
387 self.to_context_internal()
391 impl ToBase32 for InvoiceFeatures {
392 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
393 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
394 // minus one before dividing
395 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
396 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
397 for (byte_idx, byte) in self.flags.iter().enumerate() {
398 let bit_pos_from_left_0_indexed = byte_idx * 8;
399 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
400 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
401 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
402 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
403 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
405 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
406 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
409 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
410 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
413 // Trim the highest feature bits.
414 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
417 writer.write(&res_u5s)
421 impl Base32Len for InvoiceFeatures {
422 fn base32_len(&self) -> usize {
423 self.to_base32().len()
427 impl FromBase32 for InvoiceFeatures {
428 type Err = bech32::Error;
430 fn from_base32(field_data: &[u5]) -> Result<InvoiceFeatures, bech32::Error> {
431 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
432 // minus one before dividing
433 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
434 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
435 for (u5_idx, chunk) in field_data.iter().enumerate() {
436 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
437 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
438 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
439 let chunk_u16 = chunk.to_u8() as u16;
440 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
441 if new_byte_idx != length_bytes - 1 {
442 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
445 // Trim the highest feature bits.
446 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
449 Ok(InvoiceFeatures::from_le_bytes(res_bytes))
453 impl<T: sealed::Context> Features<T> {
454 /// Create a blank Features with no features set
455 pub fn empty() -> Self {
462 /// Creates a Features with the bits set which are known by the implementation
463 pub fn known() -> Self {
465 flags: T::KNOWN_FEATURE_FLAGS.to_vec(),
470 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
471 /// included in the result.
472 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
473 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
474 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
475 let mut flags = Vec::new();
476 for (i, byte) in self.flags.iter().enumerate() {
477 if i < from_byte_count && i < to_byte_count {
478 let from_known_features = T::KNOWN_FEATURE_MASK[i];
479 let to_known_features = C::KNOWN_FEATURE_MASK[i];
480 flags.push(byte & from_known_features & to_known_features);
483 Features::<C> { flags, mark: PhantomData, }
486 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
487 /// most on-the-wire encodings.
488 /// (C-not exported) as we don't support export across multiple T
489 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
497 /// Gets the underlying flags set, in LE.
498 pub fn le_flags(&self) -> &Vec<u8> {
502 pub(crate) fn requires_unknown_bits(&self) -> bool {
503 // Bitwise AND-ing with all even bits set except for known features will select required
505 let byte_count = T::KNOWN_FEATURE_MASK.len();
506 self.flags.iter().enumerate().any(|(i, &byte)| {
507 let required_features = 0b01_01_01_01;
508 let unknown_features = if i < byte_count {
509 !T::KNOWN_FEATURE_MASK[i]
513 (byte & (required_features & unknown_features)) != 0
517 pub(crate) fn supports_unknown_bits(&self) -> bool {
518 // Bitwise AND-ing with all even and odd bits set except for known features will select
519 // both required and optional unknown features.
520 let byte_count = T::KNOWN_FEATURE_MASK.len();
521 self.flags.iter().enumerate().any(|(i, &byte)| {
522 let unknown_features = if i < byte_count {
523 !T::KNOWN_FEATURE_MASK[i]
527 (byte & unknown_features) != 0
531 /// The number of bytes required to represent the feature flags present. This does not include
532 /// the length bytes which are included in the serialized form.
533 pub(crate) fn byte_count(&self) -> usize {
538 impl<T: sealed::DataLossProtect> Features<T> {
540 pub(crate) fn requires_data_loss_protect(&self) -> bool {
541 <T as sealed::DataLossProtect>::requires_feature(&self.flags)
543 pub(crate) fn supports_data_loss_protect(&self) -> bool {
544 <T as sealed::DataLossProtect>::supports_feature(&self.flags)
548 impl<T: sealed::UpfrontShutdownScript> Features<T> {
550 pub(crate) fn requires_upfront_shutdown_script(&self) -> bool {
551 <T as sealed::UpfrontShutdownScript>::requires_feature(&self.flags)
553 pub(crate) fn supports_upfront_shutdown_script(&self) -> bool {
554 <T as sealed::UpfrontShutdownScript>::supports_feature(&self.flags)
557 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
558 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
564 impl<T: sealed::GossipQueries> Features<T> {
566 pub(crate) fn requires_gossip_queries(&self) -> bool {
567 <T as sealed::GossipQueries>::requires_feature(&self.flags)
569 pub(crate) fn supports_gossip_queries(&self) -> bool {
570 <T as sealed::GossipQueries>::supports_feature(&self.flags)
573 pub(crate) fn clear_gossip_queries(mut self) -> Self {
574 <T as sealed::GossipQueries>::clear_bits(&mut self.flags);
579 impl<T: sealed::VariableLengthOnion> Features<T> {
581 pub(crate) fn requires_variable_length_onion(&self) -> bool {
582 <T as sealed::VariableLengthOnion>::requires_feature(&self.flags)
584 pub(crate) fn supports_variable_length_onion(&self) -> bool {
585 <T as sealed::VariableLengthOnion>::supports_feature(&self.flags)
589 impl<T: sealed::StaticRemoteKey> Features<T> {
590 pub(crate) fn supports_static_remote_key(&self) -> bool {
591 <T as sealed::StaticRemoteKey>::supports_feature(&self.flags)
594 pub(crate) fn requires_static_remote_key(&self) -> bool {
595 <T as sealed::StaticRemoteKey>::requires_feature(&self.flags)
599 impl<T: sealed::InitialRoutingSync> Features<T> {
600 pub(crate) fn initial_routing_sync(&self) -> bool {
601 <T as sealed::InitialRoutingSync>::supports_feature(&self.flags)
603 // We are no longer setting initial_routing_sync now that gossip_queries
604 // is enabled. This feature is ignored by a peer when gossip_queries has
607 pub(crate) fn clear_initial_routing_sync(&mut self) {
608 <T as sealed::InitialRoutingSync>::clear_bits(&mut self.flags)
612 impl<T: sealed::PaymentSecret> Features<T> {
614 pub(crate) fn requires_payment_secret(&self) -> bool {
615 <T as sealed::PaymentSecret>::requires_feature(&self.flags)
617 /// Returns whether the `payment_secret` feature is supported.
618 pub fn supports_payment_secret(&self) -> bool {
619 <T as sealed::PaymentSecret>::supports_feature(&self.flags)
623 impl<T: sealed::BasicMPP> Features<T> {
625 pub(crate) fn requires_basic_mpp(&self) -> bool {
626 <T as sealed::BasicMPP>::requires_feature(&self.flags)
628 // We currently never test for this since we don't actually *generate* multipath routes.
629 pub(crate) fn supports_basic_mpp(&self) -> bool {
630 <T as sealed::BasicMPP>::supports_feature(&self.flags)
634 impl<T: sealed::ShutdownAnySegwit> Features<T> {
635 pub(crate) fn supports_shutdown_anysegwit(&self) -> bool {
636 <T as sealed::ShutdownAnySegwit>::supports_feature(&self.flags)
639 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
640 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
645 impl<T: sealed::Context> Writeable for Features<T> {
646 fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
647 w.size_hint(self.flags.len() + 2);
648 (self.flags.len() as u16).write(w)?;
649 for f in self.flags.iter().rev() { // Swap back to big-endian
656 impl<T: sealed::Context> Readable for Features<T> {
657 fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
658 let mut flags: Vec<u8> = Readable::read(r)?;
659 flags.reverse(); // Swap to little-endian
669 use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
670 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
673 fn sanity_test_known_features() {
674 assert!(!ChannelFeatures::known().requires_unknown_bits());
675 assert!(!ChannelFeatures::known().supports_unknown_bits());
676 assert!(!InitFeatures::known().requires_unknown_bits());
677 assert!(!InitFeatures::known().supports_unknown_bits());
678 assert!(!NodeFeatures::known().requires_unknown_bits());
679 assert!(!NodeFeatures::known().supports_unknown_bits());
681 assert!(InitFeatures::known().supports_upfront_shutdown_script());
682 assert!(NodeFeatures::known().supports_upfront_shutdown_script());
683 assert!(!InitFeatures::known().requires_upfront_shutdown_script());
684 assert!(!NodeFeatures::known().requires_upfront_shutdown_script());
686 assert!(InitFeatures::known().supports_gossip_queries());
687 assert!(NodeFeatures::known().supports_gossip_queries());
688 assert!(!InitFeatures::known().requires_gossip_queries());
689 assert!(!NodeFeatures::known().requires_gossip_queries());
691 assert!(InitFeatures::known().supports_data_loss_protect());
692 assert!(NodeFeatures::known().supports_data_loss_protect());
693 assert!(!InitFeatures::known().requires_data_loss_protect());
694 assert!(!NodeFeatures::known().requires_data_loss_protect());
696 assert!(InitFeatures::known().supports_variable_length_onion());
697 assert!(NodeFeatures::known().supports_variable_length_onion());
698 assert!(InvoiceFeatures::known().supports_variable_length_onion());
699 assert!(InitFeatures::known().requires_variable_length_onion());
700 assert!(NodeFeatures::known().requires_variable_length_onion());
701 assert!(InvoiceFeatures::known().requires_variable_length_onion());
703 assert!(InitFeatures::known().supports_static_remote_key());
704 assert!(NodeFeatures::known().supports_static_remote_key());
705 assert!(InitFeatures::known().requires_static_remote_key());
706 assert!(NodeFeatures::known().requires_static_remote_key());
708 assert!(InitFeatures::known().supports_payment_secret());
709 assert!(NodeFeatures::known().supports_payment_secret());
710 assert!(InvoiceFeatures::known().supports_payment_secret());
711 assert!(InitFeatures::known().requires_payment_secret());
712 assert!(NodeFeatures::known().requires_payment_secret());
713 assert!(InvoiceFeatures::known().requires_payment_secret());
715 assert!(InitFeatures::known().supports_basic_mpp());
716 assert!(NodeFeatures::known().supports_basic_mpp());
717 assert!(InvoiceFeatures::known().supports_basic_mpp());
718 assert!(!InitFeatures::known().requires_basic_mpp());
719 assert!(!NodeFeatures::known().requires_basic_mpp());
720 assert!(!InvoiceFeatures::known().requires_basic_mpp());
722 assert!(InitFeatures::known().supports_shutdown_anysegwit());
723 assert!(NodeFeatures::known().supports_shutdown_anysegwit());
725 let mut init_features = InitFeatures::known();
726 assert!(init_features.initial_routing_sync());
727 init_features.clear_initial_routing_sync();
728 assert!(!init_features.initial_routing_sync());
732 fn sanity_test_unknown_bits() {
733 let features = ChannelFeatures::empty();
734 assert!(!features.requires_unknown_bits());
735 assert!(!features.supports_unknown_bits());
737 let features = ChannelFeatures::empty().set_unknown_feature_required();
738 assert!(features.requires_unknown_bits());
739 assert!(features.supports_unknown_bits());
741 let features = ChannelFeatures::empty().set_unknown_feature_optional();
742 assert!(!features.requires_unknown_bits());
743 assert!(features.supports_unknown_bits());
747 fn convert_to_context_with_relevant_flags() {
748 let init_features = InitFeatures::known().clear_upfront_shutdown_script().clear_gossip_queries();
749 assert!(init_features.initial_routing_sync());
750 assert!(!init_features.supports_upfront_shutdown_script());
751 assert!(!init_features.supports_gossip_queries());
753 let node_features: NodeFeatures = init_features.to_context();
755 // Check that the flags are as expected:
756 // - option_data_loss_protect
757 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
759 // - opt_shutdown_anysegwit
760 assert_eq!(node_features.flags.len(), 4);
761 assert_eq!(node_features.flags[0], 0b00000010);
762 assert_eq!(node_features.flags[1], 0b01010001);
763 assert_eq!(node_features.flags[2], 0b00000010);
764 assert_eq!(node_features.flags[3], 0b00001000);
767 // Check that cleared flags are kept blank when converting back:
768 // - initial_routing_sync was not applicable to NodeContext
769 // - upfront_shutdown_script was cleared before converting
770 // - gossip_queries was cleared before converting
771 let features: InitFeatures = node_features.to_context_internal();
772 assert!(!features.initial_routing_sync());
773 assert!(!features.supports_upfront_shutdown_script());
774 assert!(!init_features.supports_gossip_queries());
778 fn convert_to_context_with_unknown_flags() {
779 // Ensure the `from` context has fewer known feature bytes than the `to` context.
780 assert!(InvoiceFeatures::known().byte_count() < NodeFeatures::known().byte_count());
781 let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional();
782 assert!(invoice_features.supports_unknown_bits());
783 let node_features: NodeFeatures = invoice_features.to_context();
784 assert!(!node_features.supports_unknown_bits());
788 fn set_feature_bits() {
789 let features = InvoiceFeatures::empty()
790 .set_basic_mpp_optional()
791 .set_payment_secret_required();
792 assert!(features.supports_basic_mpp());
793 assert!(!features.requires_basic_mpp());
794 assert!(features.requires_payment_secret());
795 assert!(features.supports_payment_secret());
799 fn invoice_features_encoding() {
800 let features_as_u5s = vec![
801 u5::try_from_u8(6).unwrap(),
802 u5::try_from_u8(10).unwrap(),
803 u5::try_from_u8(25).unwrap(),
804 u5::try_from_u8(1).unwrap(),
805 u5::try_from_u8(10).unwrap(),
806 u5::try_from_u8(0).unwrap(),
807 u5::try_from_u8(20).unwrap(),
808 u5::try_from_u8(2).unwrap(),
809 u5::try_from_u8(0).unwrap(),
810 u5::try_from_u8(6).unwrap(),
811 u5::try_from_u8(0).unwrap(),
812 u5::try_from_u8(16).unwrap(),
813 u5::try_from_u8(1).unwrap(),
815 let features = InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
817 // Test length calculation.
818 assert_eq!(features.base32_len(), 13);
820 // Test serialization.
821 let features_serialized = features.to_base32();
822 assert_eq!(features_as_u5s, features_serialized);
824 // Test deserialization.
825 let features_deserialized = InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
826 assert_eq!(features, features_deserialized);