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 $optional_feature>::OPTIONAL_MASK)*,
93 impl alloc::fmt::Display for Features<$context> {
94 fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
97 fmt.write_fmt(format_args!("{}: {}, ", stringify!($required_feature),
98 if <$context as $required_feature>::requires_feature(&self.flags) { "required" }
99 else if <$context as $required_feature>::supports_feature(&self.flags) { "supported" }
100 else { "not supported" }))?;
103 fmt.write_fmt(format_args!("{}: {}, ", stringify!($optional_feature),
104 if <$context as $optional_feature>::requires_feature(&self.flags) { "required" }
105 else if <$context as $optional_feature>::supports_feature(&self.flags) { "supported" }
106 else { "not supported" }))?;
109 fmt.write_fmt(format_args!("unknown flags: {}",
110 if self.requires_unknown_bits() { "required" }
111 else if self.supports_unknown_bits() { "supported" } else { "none" }))
117 define_context!(InitContext {
122 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
130 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
139 define_context!(NodeContext {
144 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
158 DataLossProtect | UpfrontShutdownScript | GossipQueries,
173 define_context!(ChannelContext {
174 required_features: [],
175 optional_features: [],
177 define_context!(InvoiceContext {
182 VariableLengthOnion | PaymentSecret,
196 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
197 /// useful for manipulating feature flags.
198 macro_rules! define_feature {
199 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
200 $required_setter: ident) => {
203 /// See [BOLT #9] for details.
205 /// [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
206 pub trait $feature: Context {
207 /// The bit used to signify that the feature is required.
208 const EVEN_BIT: usize = $odd_bit - 1;
210 /// The bit used to signify that the feature is optional.
211 const ODD_BIT: usize = $odd_bit;
213 /// Assertion that [`EVEN_BIT`] is actually even.
215 /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
216 const ASSERT_EVEN_BIT_PARITY: usize;
218 /// Assertion that [`ODD_BIT`] is actually odd.
220 /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
221 const ASSERT_ODD_BIT_PARITY: usize;
223 /// The byte where the feature is set.
224 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
226 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
228 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
229 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
231 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
233 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
234 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
236 /// Returns whether the feature is required by the given flags.
238 fn requires_feature(flags: &Vec<u8>) -> bool {
239 flags.len() > Self::BYTE_OFFSET &&
240 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
243 /// Returns whether the feature is supported by the given flags.
245 fn supports_feature(flags: &Vec<u8>) -> bool {
246 flags.len() > Self::BYTE_OFFSET &&
247 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
250 /// Sets the feature's required (even) bit in the given flags.
252 fn set_required_bit(flags: &mut Vec<u8>) {
253 if flags.len() <= Self::BYTE_OFFSET {
254 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
257 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
260 /// Sets the feature's optional (odd) bit in the given flags.
262 fn set_optional_bit(flags: &mut Vec<u8>) {
263 if flags.len() <= Self::BYTE_OFFSET {
264 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
267 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
270 /// Clears the feature's required (even) and optional (odd) bits from the given
273 fn clear_bits(flags: &mut Vec<u8>) {
274 if flags.len() > Self::BYTE_OFFSET {
275 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
276 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
279 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
280 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
281 flags.resize(size, 0u8);
285 impl <T: $feature> Features<T> {
286 /// Set this feature as optional.
287 pub fn $optional_setter(mut self) -> Self {
288 <T as $feature>::set_optional_bit(&mut self.flags);
292 /// Set this feature as required.
293 pub fn $required_setter(mut self) -> Self {
294 <T as $feature>::set_required_bit(&mut self.flags);
300 impl $feature for $context {
302 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
305 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
312 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
313 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
314 set_data_loss_protect_required);
315 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
316 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
317 set_initial_routing_sync_optional, set_initial_routing_sync_required);
318 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
319 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
320 set_upfront_shutdown_script_required);
321 define_feature!(7, GossipQueries, [InitContext, NodeContext],
322 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required);
323 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext],
324 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
325 set_variable_length_onion_required);
326 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext],
327 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
328 set_static_remote_key_required);
329 define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
330 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required);
331 define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
332 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required);
333 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
334 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
335 set_shutdown_any_segwit_required);
336 define_feature!(55, Keysend, [NodeContext],
337 "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required);
340 define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
341 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
342 set_unknown_feature_required);
345 /// Tracks the set of features which a node implements, templated by the context in which it
348 /// (C-not exported) as we map the concrete feature types below directly instead
350 pub struct Features<T: sealed::Context> {
351 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
353 mark: PhantomData<T>,
356 impl<T: sealed::Context> Clone for Features<T> {
357 fn clone(&self) -> Self {
359 flags: self.flags.clone(),
364 impl<T: sealed::Context> PartialEq for Features<T> {
365 fn eq(&self, o: &Self) -> bool {
366 self.flags.eq(&o.flags)
369 impl<T: sealed::Context> fmt::Debug for Features<T> {
370 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
375 /// Features used within an `init` message.
376 pub type InitFeatures = Features<sealed::InitContext>;
377 /// Features used within a `node_announcement` message.
378 pub type NodeFeatures = Features<sealed::NodeContext>;
379 /// Features used within a `channel_announcement` message.
380 pub type ChannelFeatures = Features<sealed::ChannelContext>;
381 /// Features used within an invoice.
382 pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
385 /// Writes all features present up to, and including, 13.
386 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
387 let len = cmp::min(2, self.flags.len());
388 w.size_hint(len + 2);
389 (len as u16).write(w)?;
390 for i in (0..len).rev() {
392 self.flags[i].write(w)?;
394 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
395 // up-to-and-including-bit-5, 0-indexed, on this byte:
396 (self.flags[i] & 0b00_11_11_11).write(w)?;
402 /// or's another InitFeatures into this one.
403 pub(crate) fn or(mut self, o: InitFeatures) -> InitFeatures {
404 let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
405 self.flags.resize(total_feature_len, 0u8);
406 for (byte, o_byte) in self.flags.iter_mut().zip(o.flags.iter()) {
412 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
413 /// are included in the result.
414 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
415 self.to_context_internal()
419 impl InvoiceFeatures {
420 /// Converts `InvoiceFeatures` to `Features<C>`. Only known `InvoiceFeatures` relevant to
421 /// context `C` are included in the result.
422 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
423 self.to_context_internal()
426 /// Getting a route for a keysend payment to a private node requires providing the payee's
427 /// features (since they were not announced in a node announcement). However, keysend payments
428 /// don't have an invoice to pull the payee's features from, so this method is provided for use in
429 /// [`get_keysend_route`], thus omitting the need for payers to manually construct an
430 /// `InvoiceFeatures` for [`get_route`].
432 /// [`get_keysend_route`]: crate::routing::router::get_keysend_route
433 /// [`get_route`]: crate::routing::router::get_route
434 pub(crate) fn for_keysend() -> InvoiceFeatures {
435 InvoiceFeatures::empty().set_variable_length_onion_optional()
439 impl ToBase32 for InvoiceFeatures {
440 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
441 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
442 // minus one before dividing
443 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
444 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
445 for (byte_idx, byte) in self.flags.iter().enumerate() {
446 let bit_pos_from_left_0_indexed = byte_idx * 8;
447 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
448 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
449 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
450 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
451 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
453 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
454 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
457 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
458 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
461 // Trim the highest feature bits.
462 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
465 writer.write(&res_u5s)
469 impl Base32Len for InvoiceFeatures {
470 fn base32_len(&self) -> usize {
471 self.to_base32().len()
475 impl FromBase32 for InvoiceFeatures {
476 type Err = bech32::Error;
478 fn from_base32(field_data: &[u5]) -> Result<InvoiceFeatures, bech32::Error> {
479 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
480 // minus one before dividing
481 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
482 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
483 for (u5_idx, chunk) in field_data.iter().enumerate() {
484 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
485 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
486 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
487 let chunk_u16 = chunk.to_u8() as u16;
488 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
489 if new_byte_idx != length_bytes - 1 {
490 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
493 // Trim the highest feature bits.
494 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
497 Ok(InvoiceFeatures::from_le_bytes(res_bytes))
501 impl<T: sealed::Context> Features<T> {
502 /// Create a blank Features with no features set
503 pub fn empty() -> Self {
510 /// Creates a Features with the bits set which are known by the implementation
511 pub fn known() -> Self {
513 flags: T::KNOWN_FEATURE_FLAGS.to_vec(),
518 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
519 /// included in the result.
520 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
521 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
522 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
523 let mut flags = Vec::new();
524 for (i, byte) in self.flags.iter().enumerate() {
525 if i < from_byte_count && i < to_byte_count {
526 let from_known_features = T::KNOWN_FEATURE_MASK[i];
527 let to_known_features = C::KNOWN_FEATURE_MASK[i];
528 flags.push(byte & from_known_features & to_known_features);
531 Features::<C> { flags, mark: PhantomData, }
534 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
535 /// most on-the-wire encodings.
536 /// (C-not exported) as we don't support export across multiple T
537 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
545 /// Gets the underlying flags set, in LE.
546 pub fn le_flags(&self) -> &Vec<u8> {
550 pub(crate) fn requires_unknown_bits(&self) -> bool {
551 // Bitwise AND-ing with all even bits set except for known features will select required
553 let byte_count = T::KNOWN_FEATURE_MASK.len();
554 self.flags.iter().enumerate().any(|(i, &byte)| {
555 let required_features = 0b01_01_01_01;
556 let unknown_features = if i < byte_count {
557 !T::KNOWN_FEATURE_MASK[i]
561 (byte & (required_features & unknown_features)) != 0
565 pub(crate) fn supports_unknown_bits(&self) -> bool {
566 // Bitwise AND-ing with all even and odd bits set except for known features will select
567 // both required and optional unknown features.
568 let byte_count = T::KNOWN_FEATURE_MASK.len();
569 self.flags.iter().enumerate().any(|(i, &byte)| {
570 let unknown_features = if i < byte_count {
571 !T::KNOWN_FEATURE_MASK[i]
575 (byte & unknown_features) != 0
579 /// The number of bytes required to represent the feature flags present. This does not include
580 /// the length bytes which are included in the serialized form.
581 pub(crate) fn byte_count(&self) -> usize {
586 impl<T: sealed::DataLossProtect> Features<T> {
588 pub(crate) fn requires_data_loss_protect(&self) -> bool {
589 <T as sealed::DataLossProtect>::requires_feature(&self.flags)
592 pub(crate) fn supports_data_loss_protect(&self) -> bool {
593 <T as sealed::DataLossProtect>::supports_feature(&self.flags)
597 impl<T: sealed::UpfrontShutdownScript> Features<T> {
599 pub(crate) fn requires_upfront_shutdown_script(&self) -> bool {
600 <T as sealed::UpfrontShutdownScript>::requires_feature(&self.flags)
602 pub(crate) fn supports_upfront_shutdown_script(&self) -> bool {
603 <T as sealed::UpfrontShutdownScript>::supports_feature(&self.flags)
606 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
607 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
613 impl<T: sealed::GossipQueries> Features<T> {
615 pub(crate) fn requires_gossip_queries(&self) -> bool {
616 <T as sealed::GossipQueries>::requires_feature(&self.flags)
618 pub(crate) fn supports_gossip_queries(&self) -> bool {
619 <T as sealed::GossipQueries>::supports_feature(&self.flags)
622 pub(crate) fn clear_gossip_queries(mut self) -> Self {
623 <T as sealed::GossipQueries>::clear_bits(&mut self.flags);
628 impl<T: sealed::VariableLengthOnion> Features<T> {
630 pub(crate) fn requires_variable_length_onion(&self) -> bool {
631 <T as sealed::VariableLengthOnion>::requires_feature(&self.flags)
633 pub(crate) fn supports_variable_length_onion(&self) -> bool {
634 <T as sealed::VariableLengthOnion>::supports_feature(&self.flags)
638 impl<T: sealed::StaticRemoteKey> Features<T> {
639 pub(crate) fn supports_static_remote_key(&self) -> bool {
640 <T as sealed::StaticRemoteKey>::supports_feature(&self.flags)
643 pub(crate) fn requires_static_remote_key(&self) -> bool {
644 <T as sealed::StaticRemoteKey>::requires_feature(&self.flags)
648 impl<T: sealed::InitialRoutingSync> Features<T> {
649 pub(crate) fn initial_routing_sync(&self) -> bool {
650 <T as sealed::InitialRoutingSync>::supports_feature(&self.flags)
652 // We are no longer setting initial_routing_sync now that gossip_queries
653 // is enabled. This feature is ignored by a peer when gossip_queries has
656 pub(crate) fn clear_initial_routing_sync(&mut self) {
657 <T as sealed::InitialRoutingSync>::clear_bits(&mut self.flags)
661 impl<T: sealed::PaymentSecret> Features<T> {
663 pub(crate) fn requires_payment_secret(&self) -> bool {
664 <T as sealed::PaymentSecret>::requires_feature(&self.flags)
666 /// Returns whether the `payment_secret` feature is supported.
667 pub fn supports_payment_secret(&self) -> bool {
668 <T as sealed::PaymentSecret>::supports_feature(&self.flags)
672 impl<T: sealed::BasicMPP> Features<T> {
674 pub(crate) fn requires_basic_mpp(&self) -> bool {
675 <T as sealed::BasicMPP>::requires_feature(&self.flags)
677 // We currently never test for this since we don't actually *generate* multipath routes.
678 pub(crate) fn supports_basic_mpp(&self) -> bool {
679 <T as sealed::BasicMPP>::supports_feature(&self.flags)
683 impl<T: sealed::ShutdownAnySegwit> Features<T> {
684 pub(crate) fn supports_shutdown_anysegwit(&self) -> bool {
685 <T as sealed::ShutdownAnySegwit>::supports_feature(&self.flags)
688 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
689 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
694 impl<T: sealed::Context> Writeable for Features<T> {
695 fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
696 w.size_hint(self.flags.len() + 2);
697 (self.flags.len() as u16).write(w)?;
698 for f in self.flags.iter().rev() { // Swap back to big-endian
705 impl<T: sealed::Context> Readable for Features<T> {
706 fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
707 let mut flags: Vec<u8> = Readable::read(r)?;
708 flags.reverse(); // Swap to little-endian
718 use super::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
719 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
722 fn sanity_test_known_features() {
723 assert!(!ChannelFeatures::known().requires_unknown_bits());
724 assert!(!ChannelFeatures::known().supports_unknown_bits());
725 assert!(!InitFeatures::known().requires_unknown_bits());
726 assert!(!InitFeatures::known().supports_unknown_bits());
727 assert!(!NodeFeatures::known().requires_unknown_bits());
728 assert!(!NodeFeatures::known().supports_unknown_bits());
730 assert!(InitFeatures::known().supports_upfront_shutdown_script());
731 assert!(NodeFeatures::known().supports_upfront_shutdown_script());
732 assert!(!InitFeatures::known().requires_upfront_shutdown_script());
733 assert!(!NodeFeatures::known().requires_upfront_shutdown_script());
735 assert!(InitFeatures::known().supports_gossip_queries());
736 assert!(NodeFeatures::known().supports_gossip_queries());
737 assert!(!InitFeatures::known().requires_gossip_queries());
738 assert!(!NodeFeatures::known().requires_gossip_queries());
740 assert!(InitFeatures::known().supports_data_loss_protect());
741 assert!(NodeFeatures::known().supports_data_loss_protect());
742 assert!(!InitFeatures::known().requires_data_loss_protect());
743 assert!(!NodeFeatures::known().requires_data_loss_protect());
745 assert!(InitFeatures::known().supports_variable_length_onion());
746 assert!(NodeFeatures::known().supports_variable_length_onion());
747 assert!(InvoiceFeatures::known().supports_variable_length_onion());
748 assert!(InitFeatures::known().requires_variable_length_onion());
749 assert!(NodeFeatures::known().requires_variable_length_onion());
750 assert!(InvoiceFeatures::known().requires_variable_length_onion());
752 assert!(InitFeatures::known().supports_static_remote_key());
753 assert!(NodeFeatures::known().supports_static_remote_key());
754 assert!(InitFeatures::known().requires_static_remote_key());
755 assert!(NodeFeatures::known().requires_static_remote_key());
757 assert!(InitFeatures::known().supports_payment_secret());
758 assert!(NodeFeatures::known().supports_payment_secret());
759 assert!(InvoiceFeatures::known().supports_payment_secret());
760 assert!(InitFeatures::known().requires_payment_secret());
761 assert!(NodeFeatures::known().requires_payment_secret());
762 assert!(InvoiceFeatures::known().requires_payment_secret());
764 assert!(InitFeatures::known().supports_basic_mpp());
765 assert!(NodeFeatures::known().supports_basic_mpp());
766 assert!(InvoiceFeatures::known().supports_basic_mpp());
767 assert!(!InitFeatures::known().requires_basic_mpp());
768 assert!(!NodeFeatures::known().requires_basic_mpp());
769 assert!(!InvoiceFeatures::known().requires_basic_mpp());
771 assert!(InitFeatures::known().supports_shutdown_anysegwit());
772 assert!(NodeFeatures::known().supports_shutdown_anysegwit());
774 let mut init_features = InitFeatures::known();
775 assert!(init_features.initial_routing_sync());
776 init_features.clear_initial_routing_sync();
777 assert!(!init_features.initial_routing_sync());
781 fn sanity_test_unknown_bits() {
782 let features = ChannelFeatures::empty();
783 assert!(!features.requires_unknown_bits());
784 assert!(!features.supports_unknown_bits());
786 let features = ChannelFeatures::empty().set_unknown_feature_required();
787 assert!(features.requires_unknown_bits());
788 assert!(features.supports_unknown_bits());
790 let features = ChannelFeatures::empty().set_unknown_feature_optional();
791 assert!(!features.requires_unknown_bits());
792 assert!(features.supports_unknown_bits());
796 fn convert_to_context_with_relevant_flags() {
797 let init_features = InitFeatures::known().clear_upfront_shutdown_script().clear_gossip_queries();
798 assert!(init_features.initial_routing_sync());
799 assert!(!init_features.supports_upfront_shutdown_script());
800 assert!(!init_features.supports_gossip_queries());
802 let node_features: NodeFeatures = init_features.to_context();
804 // Check that the flags are as expected:
805 // - option_data_loss_protect
806 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
808 // - opt_shutdown_anysegwit
809 assert_eq!(node_features.flags.len(), 4);
810 assert_eq!(node_features.flags[0], 0b00000010);
811 assert_eq!(node_features.flags[1], 0b01010001);
812 assert_eq!(node_features.flags[2], 0b00000010);
813 assert_eq!(node_features.flags[3], 0b00001000);
816 // Check that cleared flags are kept blank when converting back:
817 // - initial_routing_sync was not applicable to NodeContext
818 // - upfront_shutdown_script was cleared before converting
819 // - gossip_queries was cleared before converting
820 let features: InitFeatures = node_features.to_context_internal();
821 assert!(!features.initial_routing_sync());
822 assert!(!features.supports_upfront_shutdown_script());
823 assert!(!init_features.supports_gossip_queries());
827 fn convert_to_context_with_unknown_flags() {
828 // Ensure the `from` context has fewer known feature bytes than the `to` context.
829 assert!(InvoiceFeatures::known().byte_count() < NodeFeatures::known().byte_count());
830 let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional();
831 assert!(invoice_features.supports_unknown_bits());
832 let node_features: NodeFeatures = invoice_features.to_context();
833 assert!(!node_features.supports_unknown_bits());
837 fn set_feature_bits() {
838 let features = InvoiceFeatures::empty()
839 .set_basic_mpp_optional()
840 .set_payment_secret_required();
841 assert!(features.supports_basic_mpp());
842 assert!(!features.requires_basic_mpp());
843 assert!(features.requires_payment_secret());
844 assert!(features.supports_payment_secret());
848 fn invoice_features_encoding() {
849 let features_as_u5s = vec![
850 u5::try_from_u8(6).unwrap(),
851 u5::try_from_u8(10).unwrap(),
852 u5::try_from_u8(25).unwrap(),
853 u5::try_from_u8(1).unwrap(),
854 u5::try_from_u8(10).unwrap(),
855 u5::try_from_u8(0).unwrap(),
856 u5::try_from_u8(20).unwrap(),
857 u5::try_from_u8(2).unwrap(),
858 u5::try_from_u8(0).unwrap(),
859 u5::try_from_u8(6).unwrap(),
860 u5::try_from_u8(0).unwrap(),
861 u5::try_from_u8(16).unwrap(),
862 u5::try_from_u8(1).unwrap(),
864 let features = InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
866 // Test length calculation.
867 assert_eq!(features.base32_len(), 13);
869 // Test serialization.
870 let features_serialized = features.to_base32();
871 assert_eq!(features_as_u5s, features_serialized);
873 // Test deserialization.
874 let features_deserialized = InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
875 assert_eq!(features, features_deserialized);