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
28 use core::marker::PhantomData;
31 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
32 use ln::msgs::DecodeError;
33 use util::ser::{Readable, Writeable, Writer};
37 use ln::features::Features;
39 /// The context in which [`Features`] are applicable. Defines which features are required and
40 /// which are optional for the context.
42 /// Features that are known to the implementation, where a required feature is indicated by
43 /// its even bit and an optional feature is indicated by its odd bit.
44 const KNOWN_FEATURE_FLAGS: &'static [u8];
46 /// Bitmask for selecting features that are known to the implementation, regardless of
47 /// whether each feature is required or optional.
48 const KNOWN_FEATURE_MASK: &'static [u8];
51 /// Defines a [`Context`] by stating which features it requires and which are optional. Features
52 /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
53 /// feature identifiers.
54 macro_rules! define_context {
56 required_features: [$( $( $required_feature: ident )|*, )*],
57 optional_features: [$( $( $optional_feature: ident )|*, )*],
59 #[derive(Eq, PartialEq)]
60 pub struct $context {}
62 impl Context for $context {
63 const KNOWN_FEATURE_FLAGS: &'static [u8] = &[
64 // For each byte, use bitwise-OR to compute the applicable flags for known
65 // required features `r_i` and optional features `o_j` for all `i` and `j` such
66 // that the following slice is formed:
69 // `r_0` | `r_1` | ... | `o_0` | `o_1` | ...,
74 <Self as $required_feature>::REQUIRED_MASK)*
76 <Self as $optional_feature>::OPTIONAL_MASK)*,
80 const KNOWN_FEATURE_MASK: &'static [u8] = &[
81 // Similar as above, but set both flags for each feature regardless of whether
82 // the feature is required or optional.
85 <Self as $required_feature>::REQUIRED_MASK |
86 <Self as $required_feature>::OPTIONAL_MASK)*
88 <Self as $optional_feature>::REQUIRED_MASK |
89 <Self as $optional_feature>::OPTIONAL_MASK)*,
94 impl alloc::fmt::Display for Features<$context> {
95 fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
98 fmt.write_fmt(format_args!("{}: {}, ", stringify!($required_feature),
99 if <$context as $required_feature>::requires_feature(&self.flags) { "required" }
100 else if <$context as $required_feature>::supports_feature(&self.flags) { "supported" }
101 else { "not supported" }))?;
104 fmt.write_fmt(format_args!("{}: {}, ", stringify!($optional_feature),
105 if <$context as $optional_feature>::requires_feature(&self.flags) { "required" }
106 else if <$context as $optional_feature>::supports_feature(&self.flags) { "supported" }
107 else { "not supported" }))?;
110 fmt.write_fmt(format_args!("unknown flags: {}",
111 if self.requires_unknown_bits() { "required" }
112 else if self.supports_unknown_bits() { "supported" } else { "none" }))
118 define_context!(InitContext {
123 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
131 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
140 define_context!(NodeContext {
145 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
159 DataLossProtect | UpfrontShutdownScript | GossipQueries,
174 define_context!(ChannelContext {
175 required_features: [],
176 optional_features: [],
178 define_context!(InvoiceContext {
183 VariableLengthOnion | PaymentSecret,
197 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
198 /// useful for manipulating feature flags.
199 macro_rules! define_feature {
200 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
201 $required_setter: ident) => {
204 /// See [BOLT #9] for details.
206 /// [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
207 pub trait $feature: Context {
208 /// The bit used to signify that the feature is required.
209 const EVEN_BIT: usize = $odd_bit - 1;
211 /// The bit used to signify that the feature is optional.
212 const ODD_BIT: usize = $odd_bit;
214 /// Assertion that [`EVEN_BIT`] is actually even.
216 /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
217 const ASSERT_EVEN_BIT_PARITY: usize;
219 /// Assertion that [`ODD_BIT`] is actually odd.
221 /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
222 const ASSERT_ODD_BIT_PARITY: usize;
224 /// The byte where the feature is set.
225 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
227 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
229 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
230 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
232 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
234 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
235 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
237 /// Returns whether the feature is required by the given flags.
239 fn requires_feature(flags: &Vec<u8>) -> bool {
240 flags.len() > Self::BYTE_OFFSET &&
241 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
244 /// Returns whether the feature is supported by the given flags.
246 fn supports_feature(flags: &Vec<u8>) -> bool {
247 flags.len() > Self::BYTE_OFFSET &&
248 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
251 /// Sets the feature's required (even) bit in the given flags.
253 fn set_required_bit(flags: &mut Vec<u8>) {
254 if flags.len() <= Self::BYTE_OFFSET {
255 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
258 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
261 /// Sets the feature's optional (odd) bit in the given flags.
263 fn set_optional_bit(flags: &mut Vec<u8>) {
264 if flags.len() <= Self::BYTE_OFFSET {
265 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
268 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
271 /// Clears the feature's required (even) and optional (odd) bits from the given
274 fn clear_bits(flags: &mut Vec<u8>) {
275 if flags.len() > Self::BYTE_OFFSET {
276 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
277 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
280 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
281 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
282 flags.resize(size, 0u8);
286 impl <T: $feature> Features<T> {
287 /// Set this feature as optional.
288 pub fn $optional_setter(mut self) -> Self {
289 <T as $feature>::set_optional_bit(&mut self.flags);
293 /// Set this feature as required.
294 pub fn $required_setter(mut self) -> Self {
295 <T as $feature>::set_required_bit(&mut self.flags);
301 impl $feature for $context {
303 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
306 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
313 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
314 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
315 set_data_loss_protect_required);
316 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
317 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
318 set_initial_routing_sync_optional, set_initial_routing_sync_required);
319 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
320 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
321 set_upfront_shutdown_script_required);
322 define_feature!(7, GossipQueries, [InitContext, NodeContext],
323 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required);
324 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext],
325 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
326 set_variable_length_onion_required);
327 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext],
328 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
329 set_static_remote_key_required);
330 define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
331 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required);
332 define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
333 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required);
334 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
335 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
336 set_shutdown_any_segwit_required);
337 define_feature!(55, Keysend, [NodeContext],
338 "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required);
341 define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
342 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
343 set_unknown_feature_required);
346 /// Tracks the set of features which a node implements, templated by the context in which it
349 /// (C-not exported) as we map the concrete feature types below directly instead
351 pub struct Features<T: sealed::Context> {
352 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
354 mark: PhantomData<T>,
357 impl<T: sealed::Context> Clone for Features<T> {
358 fn clone(&self) -> Self {
360 flags: self.flags.clone(),
365 impl<T: sealed::Context> PartialEq for Features<T> {
366 fn eq(&self, o: &Self) -> bool {
367 self.flags.eq(&o.flags)
370 impl<T: sealed::Context> fmt::Debug for Features<T> {
371 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
376 /// Features used within an `init` message.
377 pub type InitFeatures = Features<sealed::InitContext>;
378 /// Features used within a `node_announcement` message.
379 pub type NodeFeatures = Features<sealed::NodeContext>;
380 /// Features used within a `channel_announcement` message.
381 pub type ChannelFeatures = Features<sealed::ChannelContext>;
382 /// Features used within an invoice.
383 pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
386 /// Writes all features present up to, and including, 13.
387 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
388 let len = cmp::min(2, self.flags.len());
389 w.size_hint(len + 2);
390 (len as u16).write(w)?;
391 for i in (0..len).rev() {
393 self.flags[i].write(w)?;
395 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
396 // up-to-and-including-bit-5, 0-indexed, on this byte:
397 (self.flags[i] & 0b00_11_11_11).write(w)?;
403 /// or's another InitFeatures into this one.
404 pub(crate) fn or(mut self, o: InitFeatures) -> InitFeatures {
405 let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
406 self.flags.resize(total_feature_len, 0u8);
407 for (byte, o_byte) in self.flags.iter_mut().zip(o.flags.iter()) {
413 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
414 /// are included in the result.
415 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
416 self.to_context_internal()
420 impl InvoiceFeatures {
421 /// Converts `InvoiceFeatures` to `Features<C>`. Only known `InvoiceFeatures` relevant to
422 /// context `C` are included in the result.
423 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
424 self.to_context_internal()
427 /// Getting a route for a keysend payment to a private node requires providing the payee's
428 /// features (since they were not announced in a node announcement). However, keysend payments
429 /// don't have an invoice to pull the payee's features from, so this method is provided for use in
430 /// [`get_keysend_route`], thus omitting the need for payers to manually construct an
431 /// `InvoiceFeatures` for [`get_route`].
433 /// [`get_keysend_route`]: crate::routing::router::get_keysend_route
434 /// [`get_route`]: crate::routing::router::get_route
435 pub(crate) fn for_keysend() -> InvoiceFeatures {
436 InvoiceFeatures::empty().set_variable_length_onion_optional()
440 impl ToBase32 for InvoiceFeatures {
441 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
442 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
443 // minus one before dividing
444 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
445 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
446 for (byte_idx, byte) in self.flags.iter().enumerate() {
447 let bit_pos_from_left_0_indexed = byte_idx * 8;
448 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
449 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
450 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
451 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
452 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
454 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
455 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
458 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
459 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
462 // Trim the highest feature bits.
463 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
466 writer.write(&res_u5s)
470 impl Base32Len for InvoiceFeatures {
471 fn base32_len(&self) -> usize {
472 self.to_base32().len()
476 impl FromBase32 for InvoiceFeatures {
477 type Err = bech32::Error;
479 fn from_base32(field_data: &[u5]) -> Result<InvoiceFeatures, bech32::Error> {
480 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
481 // minus one before dividing
482 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
483 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
484 for (u5_idx, chunk) in field_data.iter().enumerate() {
485 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
486 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
487 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
488 let chunk_u16 = chunk.to_u8() as u16;
489 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
490 if new_byte_idx != length_bytes - 1 {
491 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
494 // Trim the highest feature bits.
495 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
498 Ok(InvoiceFeatures::from_le_bytes(res_bytes))
502 impl<T: sealed::Context> Features<T> {
503 /// Create a blank Features with no features set
504 pub fn empty() -> Self {
511 /// Creates a Features with the bits set which are known by the implementation
512 pub fn known() -> Self {
514 flags: T::KNOWN_FEATURE_FLAGS.to_vec(),
519 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
520 /// included in the result.
521 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
522 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
523 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
524 let mut flags = Vec::new();
525 for (i, byte) in self.flags.iter().enumerate() {
526 if i < from_byte_count && i < to_byte_count {
527 let from_known_features = T::KNOWN_FEATURE_MASK[i];
528 let to_known_features = C::KNOWN_FEATURE_MASK[i];
529 flags.push(byte & from_known_features & to_known_features);
532 Features::<C> { flags, mark: PhantomData, }
535 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
536 /// most on-the-wire encodings.
537 /// (C-not exported) as we don't support export across multiple T
538 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
546 /// Gets the underlying flags set, in LE.
547 pub fn le_flags(&self) -> &Vec<u8> {
551 pub(crate) fn requires_unknown_bits(&self) -> bool {
552 // Bitwise AND-ing with all even bits set except for known features will select required
554 let byte_count = T::KNOWN_FEATURE_MASK.len();
555 self.flags.iter().enumerate().any(|(i, &byte)| {
556 let required_features = 0b01_01_01_01;
557 let unknown_features = if i < byte_count {
558 !T::KNOWN_FEATURE_MASK[i]
562 (byte & (required_features & unknown_features)) != 0
566 pub(crate) fn supports_unknown_bits(&self) -> bool {
567 // Bitwise AND-ing with all even and odd bits set except for known features will select
568 // both required and optional unknown features.
569 let byte_count = T::KNOWN_FEATURE_MASK.len();
570 self.flags.iter().enumerate().any(|(i, &byte)| {
571 let unknown_features = if i < byte_count {
572 !T::KNOWN_FEATURE_MASK[i]
576 (byte & unknown_features) != 0
580 /// The number of bytes required to represent the feature flags present. This does not include
581 /// the length bytes which are included in the serialized form.
582 pub(crate) fn byte_count(&self) -> usize {
587 impl<T: sealed::DataLossProtect> Features<T> {
589 pub(crate) fn requires_data_loss_protect(&self) -> bool {
590 <T as sealed::DataLossProtect>::requires_feature(&self.flags)
593 pub(crate) fn supports_data_loss_protect(&self) -> bool {
594 <T as sealed::DataLossProtect>::supports_feature(&self.flags)
598 impl<T: sealed::UpfrontShutdownScript> Features<T> {
600 pub(crate) fn requires_upfront_shutdown_script(&self) -> bool {
601 <T as sealed::UpfrontShutdownScript>::requires_feature(&self.flags)
603 pub(crate) fn supports_upfront_shutdown_script(&self) -> bool {
604 <T as sealed::UpfrontShutdownScript>::supports_feature(&self.flags)
607 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
608 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
614 impl<T: sealed::GossipQueries> Features<T> {
616 pub(crate) fn requires_gossip_queries(&self) -> bool {
617 <T as sealed::GossipQueries>::requires_feature(&self.flags)
619 pub(crate) fn supports_gossip_queries(&self) -> bool {
620 <T as sealed::GossipQueries>::supports_feature(&self.flags)
623 pub(crate) fn clear_gossip_queries(mut self) -> Self {
624 <T as sealed::GossipQueries>::clear_bits(&mut self.flags);
629 impl<T: sealed::VariableLengthOnion> Features<T> {
631 pub(crate) fn requires_variable_length_onion(&self) -> bool {
632 <T as sealed::VariableLengthOnion>::requires_feature(&self.flags)
634 pub(crate) fn supports_variable_length_onion(&self) -> bool {
635 <T as sealed::VariableLengthOnion>::supports_feature(&self.flags)
639 impl<T: sealed::StaticRemoteKey> Features<T> {
640 pub(crate) fn supports_static_remote_key(&self) -> bool {
641 <T as sealed::StaticRemoteKey>::supports_feature(&self.flags)
644 pub(crate) fn requires_static_remote_key(&self) -> bool {
645 <T as sealed::StaticRemoteKey>::requires_feature(&self.flags)
649 impl<T: sealed::InitialRoutingSync> Features<T> {
650 pub(crate) fn initial_routing_sync(&self) -> bool {
651 <T as sealed::InitialRoutingSync>::supports_feature(&self.flags)
653 // We are no longer setting initial_routing_sync now that gossip_queries
654 // is enabled. This feature is ignored by a peer when gossip_queries has
657 pub(crate) fn clear_initial_routing_sync(&mut self) {
658 <T as sealed::InitialRoutingSync>::clear_bits(&mut self.flags)
662 impl<T: sealed::PaymentSecret> Features<T> {
664 pub(crate) fn requires_payment_secret(&self) -> bool {
665 <T as sealed::PaymentSecret>::requires_feature(&self.flags)
667 /// Returns whether the `payment_secret` feature is supported.
668 pub fn supports_payment_secret(&self) -> bool {
669 <T as sealed::PaymentSecret>::supports_feature(&self.flags)
673 impl<T: sealed::BasicMPP> Features<T> {
675 pub(crate) fn requires_basic_mpp(&self) -> bool {
676 <T as sealed::BasicMPP>::requires_feature(&self.flags)
678 // We currently never test for this since we don't actually *generate* multipath routes.
679 pub(crate) fn supports_basic_mpp(&self) -> bool {
680 <T as sealed::BasicMPP>::supports_feature(&self.flags)
684 impl<T: sealed::ShutdownAnySegwit> Features<T> {
685 pub(crate) fn supports_shutdown_anysegwit(&self) -> bool {
686 <T as sealed::ShutdownAnySegwit>::supports_feature(&self.flags)
689 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
690 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
695 impl<T: sealed::Context> Writeable for Features<T> {
696 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
697 w.size_hint(self.flags.len() + 2);
698 (self.flags.len() as u16).write(w)?;
699 for f in self.flags.iter().rev() { // Swap back to big-endian
706 impl<T: sealed::Context> Readable for Features<T> {
707 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
708 let mut flags: Vec<u8> = Readable::read(r)?;
709 flags.reverse(); // Swap to little-endian
719 use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
720 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
723 fn sanity_test_known_features() {
724 assert!(!ChannelFeatures::known().requires_unknown_bits());
725 assert!(!ChannelFeatures::known().supports_unknown_bits());
726 assert!(!InitFeatures::known().requires_unknown_bits());
727 assert!(!InitFeatures::known().supports_unknown_bits());
728 assert!(!NodeFeatures::known().requires_unknown_bits());
729 assert!(!NodeFeatures::known().supports_unknown_bits());
731 assert!(InitFeatures::known().supports_upfront_shutdown_script());
732 assert!(NodeFeatures::known().supports_upfront_shutdown_script());
733 assert!(!InitFeatures::known().requires_upfront_shutdown_script());
734 assert!(!NodeFeatures::known().requires_upfront_shutdown_script());
736 assert!(InitFeatures::known().supports_gossip_queries());
737 assert!(NodeFeatures::known().supports_gossip_queries());
738 assert!(!InitFeatures::known().requires_gossip_queries());
739 assert!(!NodeFeatures::known().requires_gossip_queries());
741 assert!(InitFeatures::known().supports_data_loss_protect());
742 assert!(NodeFeatures::known().supports_data_loss_protect());
743 assert!(!InitFeatures::known().requires_data_loss_protect());
744 assert!(!NodeFeatures::known().requires_data_loss_protect());
746 assert!(InitFeatures::known().supports_variable_length_onion());
747 assert!(NodeFeatures::known().supports_variable_length_onion());
748 assert!(InvoiceFeatures::known().supports_variable_length_onion());
749 assert!(InitFeatures::known().requires_variable_length_onion());
750 assert!(NodeFeatures::known().requires_variable_length_onion());
751 assert!(InvoiceFeatures::known().requires_variable_length_onion());
753 assert!(InitFeatures::known().supports_static_remote_key());
754 assert!(NodeFeatures::known().supports_static_remote_key());
755 assert!(InitFeatures::known().requires_static_remote_key());
756 assert!(NodeFeatures::known().requires_static_remote_key());
758 assert!(InitFeatures::known().supports_payment_secret());
759 assert!(NodeFeatures::known().supports_payment_secret());
760 assert!(InvoiceFeatures::known().supports_payment_secret());
761 assert!(InitFeatures::known().requires_payment_secret());
762 assert!(NodeFeatures::known().requires_payment_secret());
763 assert!(InvoiceFeatures::known().requires_payment_secret());
765 assert!(InitFeatures::known().supports_basic_mpp());
766 assert!(NodeFeatures::known().supports_basic_mpp());
767 assert!(InvoiceFeatures::known().supports_basic_mpp());
768 assert!(!InitFeatures::known().requires_basic_mpp());
769 assert!(!NodeFeatures::known().requires_basic_mpp());
770 assert!(!InvoiceFeatures::known().requires_basic_mpp());
772 assert!(InitFeatures::known().supports_shutdown_anysegwit());
773 assert!(NodeFeatures::known().supports_shutdown_anysegwit());
775 let mut init_features = InitFeatures::known();
776 assert!(init_features.initial_routing_sync());
777 init_features.clear_initial_routing_sync();
778 assert!(!init_features.initial_routing_sync());
782 fn sanity_test_unknown_bits() {
783 let features = ChannelFeatures::empty();
784 assert!(!features.requires_unknown_bits());
785 assert!(!features.supports_unknown_bits());
787 let features = ChannelFeatures::empty().set_unknown_feature_required();
788 assert!(features.requires_unknown_bits());
789 assert!(features.supports_unknown_bits());
791 let features = ChannelFeatures::empty().set_unknown_feature_optional();
792 assert!(!features.requires_unknown_bits());
793 assert!(features.supports_unknown_bits());
797 fn convert_to_context_with_relevant_flags() {
798 let init_features = InitFeatures::known().clear_upfront_shutdown_script().clear_gossip_queries();
799 assert!(init_features.initial_routing_sync());
800 assert!(!init_features.supports_upfront_shutdown_script());
801 assert!(!init_features.supports_gossip_queries());
803 let node_features: NodeFeatures = init_features.to_context();
805 // Check that the flags are as expected:
806 // - option_data_loss_protect
807 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
809 // - opt_shutdown_anysegwit
810 assert_eq!(node_features.flags.len(), 4);
811 assert_eq!(node_features.flags[0], 0b00000010);
812 assert_eq!(node_features.flags[1], 0b01010001);
813 assert_eq!(node_features.flags[2], 0b00000010);
814 assert_eq!(node_features.flags[3], 0b00001000);
817 // Check that cleared flags are kept blank when converting back:
818 // - initial_routing_sync was not applicable to NodeContext
819 // - upfront_shutdown_script was cleared before converting
820 // - gossip_queries was cleared before converting
821 let features: InitFeatures = node_features.to_context_internal();
822 assert!(!features.initial_routing_sync());
823 assert!(!features.supports_upfront_shutdown_script());
824 assert!(!init_features.supports_gossip_queries());
828 fn convert_to_context_with_unknown_flags() {
829 // Ensure the `from` context has fewer known feature bytes than the `to` context.
830 assert!(InvoiceFeatures::known().byte_count() < NodeFeatures::known().byte_count());
831 let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional();
832 assert!(invoice_features.supports_unknown_bits());
833 let node_features: NodeFeatures = invoice_features.to_context();
834 assert!(!node_features.supports_unknown_bits());
838 fn set_feature_bits() {
839 let features = InvoiceFeatures::empty()
840 .set_basic_mpp_optional()
841 .set_payment_secret_required();
842 assert!(features.supports_basic_mpp());
843 assert!(!features.requires_basic_mpp());
844 assert!(features.requires_payment_secret());
845 assert!(features.supports_payment_secret());
849 fn invoice_features_encoding() {
850 let features_as_u5s = vec![
851 u5::try_from_u8(6).unwrap(),
852 u5::try_from_u8(10).unwrap(),
853 u5::try_from_u8(25).unwrap(),
854 u5::try_from_u8(1).unwrap(),
855 u5::try_from_u8(10).unwrap(),
856 u5::try_from_u8(0).unwrap(),
857 u5::try_from_u8(20).unwrap(),
858 u5::try_from_u8(2).unwrap(),
859 u5::try_from_u8(0).unwrap(),
860 u5::try_from_u8(6).unwrap(),
861 u5::try_from_u8(0).unwrap(),
862 u5::try_from_u8(16).unwrap(),
863 u5::try_from_u8(1).unwrap(),
865 let features = InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
867 // Test length calculation.
868 assert_eq!(features.base32_len(), 13);
870 // Test serialization.
871 let features_serialized = features.to_base32();
872 assert_eq!(features_as_u5s, features_serialized);
874 // Test deserialization.
875 let features_deserialized = InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
876 assert_eq!(features, features_deserialized);