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::hash::{Hash, Hasher};
29 use core::marker::PhantomData;
32 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
33 use ln::msgs::DecodeError;
34 use util::ser::{Readable, Writeable, Writer};
38 use ln::features::Features;
40 /// The context in which [`Features`] are applicable. Defines which features are required and
41 /// which are optional for the context.
43 /// Features that are known to the implementation, where a required feature is indicated by
44 /// its even bit and an optional feature is indicated by its odd bit.
45 const KNOWN_FEATURE_FLAGS: &'static [u8];
47 /// Bitmask for selecting features that are known to the implementation, regardless of
48 /// whether each feature is required or optional.
49 const KNOWN_FEATURE_MASK: &'static [u8];
52 /// Defines a [`Context`] by stating which features it requires and which are optional. Features
53 /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
54 /// feature identifiers.
55 macro_rules! define_context {
57 required_features: [$( $( $required_feature: ident )|*, )*],
58 optional_features: [$( $( $optional_feature: ident )|*, )*],
60 #[derive(Eq, PartialEq)]
61 pub struct $context {}
63 impl Context for $context {
64 const KNOWN_FEATURE_FLAGS: &'static [u8] = &[
65 // For each byte, use bitwise-OR to compute the applicable flags for known
66 // required features `r_i` and optional features `o_j` for all `i` and `j` such
67 // that the following slice is formed:
70 // `r_0` | `r_1` | ... | `o_0` | `o_1` | ...,
75 <Self as $required_feature>::REQUIRED_MASK)*
77 <Self as $optional_feature>::OPTIONAL_MASK)*,
81 const KNOWN_FEATURE_MASK: &'static [u8] = &[
82 // Similar as above, but set both flags for each feature regardless of whether
83 // the feature is required or optional.
86 <Self as $required_feature>::REQUIRED_MASK |
87 <Self as $required_feature>::OPTIONAL_MASK)*
89 <Self as $optional_feature>::REQUIRED_MASK |
90 <Self as $optional_feature>::OPTIONAL_MASK)*,
95 impl alloc::fmt::Display for Features<$context> {
96 fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
99 fmt.write_fmt(format_args!("{}: {}, ", stringify!($required_feature),
100 if <$context as $required_feature>::requires_feature(&self.flags) { "required" }
101 else if <$context as $required_feature>::supports_feature(&self.flags) { "supported" }
102 else { "not supported" }))?;
105 fmt.write_fmt(format_args!("{}: {}, ", stringify!($optional_feature),
106 if <$context as $optional_feature>::requires_feature(&self.flags) { "required" }
107 else if <$context as $optional_feature>::supports_feature(&self.flags) { "supported" }
108 else { "not supported" }))?;
111 fmt.write_fmt(format_args!("unknown flags: {}",
112 if self.requires_unknown_bits() { "required" }
113 else if self.supports_unknown_bits() { "supported" } else { "none" }))
119 define_context!(InitContext {
124 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
136 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
149 define_context!(NodeContext {
154 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
168 DataLossProtect | UpfrontShutdownScript | GossipQueries,
183 define_context!(ChannelContext {
184 required_features: [],
185 optional_features: [],
187 define_context!(InvoiceContext {
192 VariableLengthOnion | PaymentSecret,
205 // This isn't a "real" feature context, and is only used in the channel_type field in an
206 // `OpenChannel` message.
207 define_context!(ChannelTypeContext {
230 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
231 /// useful for manipulating feature flags.
232 macro_rules! define_feature {
233 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
234 $required_setter: ident, $supported_getter: ident) => {
237 /// See [BOLT #9] for details.
239 /// [BOLT #9]: https://github.com/lightningnetwork/lightning-rfc/blob/master/09-features.md
240 pub trait $feature: Context {
241 /// The bit used to signify that the feature is required.
242 const EVEN_BIT: usize = $odd_bit - 1;
244 /// The bit used to signify that the feature is optional.
245 const ODD_BIT: usize = $odd_bit;
247 /// Assertion that [`EVEN_BIT`] is actually even.
249 /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
250 const ASSERT_EVEN_BIT_PARITY: usize;
252 /// Assertion that [`ODD_BIT`] is actually odd.
254 /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
255 const ASSERT_ODD_BIT_PARITY: usize;
257 /// The byte where the feature is set.
258 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
260 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
262 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
263 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
265 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
267 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
268 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
270 /// Returns whether the feature is required by the given flags.
272 fn requires_feature(flags: &Vec<u8>) -> bool {
273 flags.len() > Self::BYTE_OFFSET &&
274 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
277 /// Returns whether the feature is supported by the given flags.
279 fn supports_feature(flags: &Vec<u8>) -> bool {
280 flags.len() > Self::BYTE_OFFSET &&
281 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
284 /// Sets the feature's required (even) bit in the given flags.
286 fn set_required_bit(flags: &mut Vec<u8>) {
287 if flags.len() <= Self::BYTE_OFFSET {
288 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
291 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
294 /// Sets the feature's optional (odd) bit in the given flags.
296 fn set_optional_bit(flags: &mut Vec<u8>) {
297 if flags.len() <= Self::BYTE_OFFSET {
298 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
301 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
304 /// Clears the feature's required (even) and optional (odd) bits from the given
307 fn clear_bits(flags: &mut Vec<u8>) {
308 if flags.len() > Self::BYTE_OFFSET {
309 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
310 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
313 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
314 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
315 flags.resize(size, 0u8);
319 impl <T: $feature> Features<T> {
320 /// Set this feature as optional.
321 pub fn $optional_setter(mut self) -> Self {
322 <T as $feature>::set_optional_bit(&mut self.flags);
326 /// Set this feature as required.
327 pub fn $required_setter(mut self) -> Self {
328 <T as $feature>::set_required_bit(&mut self.flags);
332 /// Checks if this feature is supported.
333 pub fn $supported_getter(&self) -> bool {
334 <T as $feature>::supports_feature(&self.flags)
339 impl $feature for $context {
341 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
344 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
348 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
349 $required_setter: ident, $supported_getter: ident, $required_getter: ident) => {
350 define_feature!($odd_bit, $feature, [$($context),+], $doc, $optional_setter, $required_setter, $supported_getter);
351 impl <T: $feature> Features<T> {
352 /// Checks if this feature is required.
353 pub fn $required_getter(&self) -> bool {
354 <T as $feature>::requires_feature(&self.flags)
360 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
361 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
362 set_data_loss_protect_required, supports_data_loss_protect, requires_data_loss_protect);
363 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
364 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
365 set_initial_routing_sync_optional, set_initial_routing_sync_required,
366 initial_routing_sync);
367 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
368 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
369 set_upfront_shutdown_script_required, supports_upfront_shutdown_script,
370 requires_upfront_shutdown_script);
371 define_feature!(7, GossipQueries, [InitContext, NodeContext],
372 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required,
373 supports_gossip_queries, requires_gossip_queries);
374 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, InvoiceContext],
375 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
376 set_variable_length_onion_required, supports_variable_length_onion,
377 requires_variable_length_onion);
378 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext, ChannelTypeContext],
379 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
380 set_static_remote_key_required, supports_static_remote_key, requires_static_remote_key);
381 define_feature!(15, PaymentSecret, [InitContext, NodeContext, InvoiceContext],
382 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required,
383 supports_payment_secret, requires_payment_secret);
384 define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
385 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
386 supports_basic_mpp, requires_basic_mpp);
387 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
388 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
389 set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
390 define_feature!(45, ChannelType, [InitContext, NodeContext],
391 "Feature flags for `option_channel_type`.", set_channel_type_optional,
392 set_channel_type_required, supports_channel_type, requires_channel_type);
393 define_feature!(55, Keysend, [NodeContext],
394 "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
395 supports_keysend, requires_keysend);
398 define_feature!(123456789, UnknownFeature, [NodeContext, ChannelContext, InvoiceContext],
399 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
400 set_unknown_feature_required, supports_unknown_test_feature, requires_unknown_test_feature);
403 /// Tracks the set of features which a node implements, templated by the context in which it
406 /// (C-not exported) as we map the concrete feature types below directly instead
408 pub struct Features<T: sealed::Context> {
409 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
411 mark: PhantomData<T>,
414 impl<T: sealed::Context> Clone for Features<T> {
415 fn clone(&self) -> Self {
417 flags: self.flags.clone(),
422 impl<T: sealed::Context> Hash for Features<T> {
423 fn hash<H: Hasher>(&self, hasher: &mut H) {
424 self.flags.hash(hasher);
427 impl<T: sealed::Context> PartialEq for Features<T> {
428 fn eq(&self, o: &Self) -> bool {
429 self.flags.eq(&o.flags)
432 impl<T: sealed::Context> fmt::Debug for Features<T> {
433 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
438 /// Features used within an `init` message.
439 pub type InitFeatures = Features<sealed::InitContext>;
440 /// Features used within a `node_announcement` message.
441 pub type NodeFeatures = Features<sealed::NodeContext>;
442 /// Features used within a `channel_announcement` message.
443 pub type ChannelFeatures = Features<sealed::ChannelContext>;
444 /// Features used within an invoice.
445 pub type InvoiceFeatures = Features<sealed::InvoiceContext>;
447 /// Features used within the channel_type field in an OpenChannel message.
449 /// A channel is always of some known "type", describing the transaction formats used and the exact
450 /// semantics of our interaction with our peer.
452 /// Note that because a channel is a specific type which is proposed by the opener and accepted by
453 /// the counterparty, only required features are allowed here.
455 /// This is serialized differently from other feature types - it is not prefixed by a length, and
456 /// thus must only appear inside a TLV where its length is known in advance.
457 pub type ChannelTypeFeatures = Features<sealed::ChannelTypeContext>;
460 /// Writes all features present up to, and including, 13.
461 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
462 let len = cmp::min(2, self.flags.len());
463 (len as u16).write(w)?;
464 for i in (0..len).rev() {
466 self.flags[i].write(w)?;
468 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
469 // up-to-and-including-bit-5, 0-indexed, on this byte:
470 (self.flags[i] & 0b00_11_11_11).write(w)?;
476 /// or's another InitFeatures into this one.
477 pub(crate) fn or(mut self, o: InitFeatures) -> InitFeatures {
478 let total_feature_len = cmp::max(self.flags.len(), o.flags.len());
479 self.flags.resize(total_feature_len, 0u8);
480 for (byte, o_byte) in self.flags.iter_mut().zip(o.flags.iter()) {
486 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
487 /// are included in the result.
488 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
489 self.to_context_internal()
493 impl InvoiceFeatures {
494 /// Converts `InvoiceFeatures` to `Features<C>`. Only known `InvoiceFeatures` relevant to
495 /// context `C` are included in the result.
496 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
497 self.to_context_internal()
500 /// Getting a route for a keysend payment to a private node requires providing the payee's
501 /// features (since they were not announced in a node announcement). However, keysend payments
502 /// don't have an invoice to pull the payee's features from, so this method is provided for use in
503 /// [`PaymentParameters::for_keysend`], thus omitting the need for payers to manually construct an
504 /// `InvoiceFeatures` for [`find_route`].
506 /// [`PaymentParameters::for_keysend`]: crate::routing::router::PaymentParameters::for_keysend
507 /// [`find_route`]: crate::routing::router::find_route
508 pub(crate) fn for_keysend() -> InvoiceFeatures {
509 InvoiceFeatures::empty().set_variable_length_onion_optional()
513 impl ChannelTypeFeatures {
514 /// Constructs the implicit channel type based on the common supported types between us and our
516 pub(crate) fn from_counterparty_init(counterparty_init: &InitFeatures) -> Self {
517 let mut ret = counterparty_init.to_context_internal();
518 // ChannelTypeFeatures must only contain required bits, so we OR the required forms of all
519 // optional bits and then AND out the optional ones.
520 for byte in ret.flags.iter_mut() {
521 *byte |= (*byte & 0b10_10_10_10) >> 1;
522 *byte &= 0b01_01_01_01;
527 /// Constructs a ChannelTypeFeatures with only static_remotekey set
528 pub(crate) fn only_static_remote_key() -> Self {
529 let mut ret = Self::empty();
530 <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
535 impl ToBase32 for InvoiceFeatures {
536 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
537 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
538 // minus one before dividing
539 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
540 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
541 for (byte_idx, byte) in self.flags.iter().enumerate() {
542 let bit_pos_from_left_0_indexed = byte_idx * 8;
543 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
544 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
545 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
546 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
547 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
549 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
550 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
553 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
554 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
557 // Trim the highest feature bits.
558 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
561 writer.write(&res_u5s)
565 impl Base32Len for InvoiceFeatures {
566 fn base32_len(&self) -> usize {
567 self.to_base32().len()
571 impl FromBase32 for InvoiceFeatures {
572 type Err = bech32::Error;
574 fn from_base32(field_data: &[u5]) -> Result<InvoiceFeatures, bech32::Error> {
575 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
576 // minus one before dividing
577 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
578 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
579 for (u5_idx, chunk) in field_data.iter().enumerate() {
580 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
581 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
582 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
583 let chunk_u16 = chunk.to_u8() as u16;
584 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
585 if new_byte_idx != length_bytes - 1 {
586 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
589 // Trim the highest feature bits.
590 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
593 Ok(InvoiceFeatures::from_le_bytes(res_bytes))
597 impl<T: sealed::Context> Features<T> {
598 /// Create a blank Features with no features set
599 pub fn empty() -> Self {
606 /// Creates a Features with the bits set which are known by the implementation
607 pub fn known() -> Self {
609 flags: T::KNOWN_FEATURE_FLAGS.to_vec(),
614 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
615 /// included in the result.
616 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
617 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
618 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
619 let mut flags = Vec::new();
620 for (i, byte) in self.flags.iter().enumerate() {
621 if i < from_byte_count && i < to_byte_count {
622 let from_known_features = T::KNOWN_FEATURE_MASK[i];
623 let to_known_features = C::KNOWN_FEATURE_MASK[i];
624 flags.push(byte & from_known_features & to_known_features);
627 Features::<C> { flags, mark: PhantomData, }
630 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
631 /// most on-the-wire encodings.
632 /// (C-not exported) as we don't support export across multiple T
633 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
641 /// Gets the underlying flags set, in LE.
642 pub fn le_flags(&self) -> &Vec<u8> {
646 fn write_be<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
647 for f in self.flags.iter().rev() { // Swap back to big-endian
653 fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
654 flags.reverse(); // Swap to little-endian
661 pub(crate) fn supports_any_optional_bits(&self) -> bool {
662 self.flags.iter().any(|&byte| (byte & 0b10_10_10_10) != 0)
665 /// Returns true if this `Features` object contains unknown feature flags which are set as
667 pub fn requires_unknown_bits(&self) -> bool {
668 // Bitwise AND-ing with all even bits set except for known features will select required
670 let byte_count = T::KNOWN_FEATURE_MASK.len();
671 self.flags.iter().enumerate().any(|(i, &byte)| {
672 let required_features = 0b01_01_01_01;
673 let unknown_features = if i < byte_count {
674 !T::KNOWN_FEATURE_MASK[i]
678 (byte & (required_features & unknown_features)) != 0
682 pub(crate) fn supports_unknown_bits(&self) -> bool {
683 // Bitwise AND-ing with all even and odd bits set except for known features will select
684 // both required and optional unknown features.
685 let byte_count = T::KNOWN_FEATURE_MASK.len();
686 self.flags.iter().enumerate().any(|(i, &byte)| {
687 let unknown_features = if i < byte_count {
688 !T::KNOWN_FEATURE_MASK[i]
692 (byte & unknown_features) != 0
697 impl<T: sealed::UpfrontShutdownScript> Features<T> {
699 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
700 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
706 impl<T: sealed::GossipQueries> Features<T> {
708 pub(crate) fn clear_gossip_queries(mut self) -> Self {
709 <T as sealed::GossipQueries>::clear_bits(&mut self.flags);
714 impl<T: sealed::InitialRoutingSync> Features<T> {
715 // We are no longer setting initial_routing_sync now that gossip_queries
716 // is enabled. This feature is ignored by a peer when gossip_queries has
719 pub(crate) fn clear_initial_routing_sync(&mut self) {
720 <T as sealed::InitialRoutingSync>::clear_bits(&mut self.flags)
724 impl<T: sealed::ShutdownAnySegwit> Features<T> {
726 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
727 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
731 macro_rules! impl_feature_len_prefixed_write {
732 ($features: ident) => {
733 impl Writeable for $features {
734 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
735 (self.flags.len() as u16).write(w)?;
739 impl Readable for $features {
740 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
741 Ok(Self::from_be_bytes(Vec::<u8>::read(r)?))
746 impl_feature_len_prefixed_write!(InitFeatures);
747 impl_feature_len_prefixed_write!(ChannelFeatures);
748 impl_feature_len_prefixed_write!(NodeFeatures);
749 impl_feature_len_prefixed_write!(InvoiceFeatures);
751 // Because ChannelTypeFeatures only appears inside of TLVs, it doesn't have a length prefix when
752 // serialized. Thus, we can't use `impl_feature_len_prefixed_write`, above, and have to write our
753 // own serialization.
754 impl Writeable for ChannelTypeFeatures {
755 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
759 impl Readable for ChannelTypeFeatures {
760 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
761 let v = io_extras::read_to_end(r)?;
762 Ok(Self::from_be_bytes(v))
768 use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
769 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
772 fn sanity_test_known_features() {
773 assert!(!ChannelFeatures::known().requires_unknown_bits());
774 assert!(!ChannelFeatures::known().supports_unknown_bits());
775 assert!(!InitFeatures::known().requires_unknown_bits());
776 assert!(!InitFeatures::known().supports_unknown_bits());
777 assert!(!NodeFeatures::known().requires_unknown_bits());
778 assert!(!NodeFeatures::known().supports_unknown_bits());
780 assert!(InitFeatures::known().supports_upfront_shutdown_script());
781 assert!(NodeFeatures::known().supports_upfront_shutdown_script());
782 assert!(!InitFeatures::known().requires_upfront_shutdown_script());
783 assert!(!NodeFeatures::known().requires_upfront_shutdown_script());
785 assert!(InitFeatures::known().supports_gossip_queries());
786 assert!(NodeFeatures::known().supports_gossip_queries());
787 assert!(!InitFeatures::known().requires_gossip_queries());
788 assert!(!NodeFeatures::known().requires_gossip_queries());
790 assert!(InitFeatures::known().supports_data_loss_protect());
791 assert!(NodeFeatures::known().supports_data_loss_protect());
792 assert!(!InitFeatures::known().requires_data_loss_protect());
793 assert!(!NodeFeatures::known().requires_data_loss_protect());
795 assert!(InitFeatures::known().supports_variable_length_onion());
796 assert!(NodeFeatures::known().supports_variable_length_onion());
797 assert!(InvoiceFeatures::known().supports_variable_length_onion());
798 assert!(InitFeatures::known().requires_variable_length_onion());
799 assert!(NodeFeatures::known().requires_variable_length_onion());
800 assert!(InvoiceFeatures::known().requires_variable_length_onion());
802 assert!(InitFeatures::known().supports_static_remote_key());
803 assert!(NodeFeatures::known().supports_static_remote_key());
804 assert!(InitFeatures::known().requires_static_remote_key());
805 assert!(NodeFeatures::known().requires_static_remote_key());
807 assert!(InitFeatures::known().supports_payment_secret());
808 assert!(NodeFeatures::known().supports_payment_secret());
809 assert!(InvoiceFeatures::known().supports_payment_secret());
810 assert!(InitFeatures::known().requires_payment_secret());
811 assert!(NodeFeatures::known().requires_payment_secret());
812 assert!(InvoiceFeatures::known().requires_payment_secret());
814 assert!(InitFeatures::known().supports_basic_mpp());
815 assert!(NodeFeatures::known().supports_basic_mpp());
816 assert!(InvoiceFeatures::known().supports_basic_mpp());
817 assert!(!InitFeatures::known().requires_basic_mpp());
818 assert!(!NodeFeatures::known().requires_basic_mpp());
819 assert!(!InvoiceFeatures::known().requires_basic_mpp());
821 assert!(InitFeatures::known().supports_channel_type());
822 assert!(NodeFeatures::known().supports_channel_type());
823 assert!(!InitFeatures::known().requires_channel_type());
824 assert!(!NodeFeatures::known().requires_channel_type());
826 assert!(InitFeatures::known().supports_shutdown_anysegwit());
827 assert!(NodeFeatures::known().supports_shutdown_anysegwit());
829 let mut init_features = InitFeatures::known();
830 assert!(init_features.initial_routing_sync());
831 init_features.clear_initial_routing_sync();
832 assert!(!init_features.initial_routing_sync());
836 fn sanity_test_unknown_bits() {
837 let features = ChannelFeatures::empty();
838 assert!(!features.requires_unknown_bits());
839 assert!(!features.supports_unknown_bits());
841 let features = ChannelFeatures::empty().set_unknown_feature_required();
842 assert!(features.requires_unknown_bits());
843 assert!(features.supports_unknown_bits());
845 let features = ChannelFeatures::empty().set_unknown_feature_optional();
846 assert!(!features.requires_unknown_bits());
847 assert!(features.supports_unknown_bits());
851 fn convert_to_context_with_relevant_flags() {
852 let init_features = InitFeatures::known().clear_upfront_shutdown_script().clear_gossip_queries();
853 assert!(init_features.initial_routing_sync());
854 assert!(!init_features.supports_upfront_shutdown_script());
855 assert!(!init_features.supports_gossip_queries());
857 let node_features: NodeFeatures = init_features.to_context();
859 // Check that the flags are as expected:
860 // - option_data_loss_protect
861 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
863 // - opt_shutdown_anysegwit
865 // - option_channel_type
866 assert_eq!(node_features.flags.len(), 6);
867 assert_eq!(node_features.flags[0], 0b00000010);
868 assert_eq!(node_features.flags[1], 0b01010001);
869 assert_eq!(node_features.flags[2], 0b00000010);
870 assert_eq!(node_features.flags[3], 0b00001000);
871 assert_eq!(node_features.flags[4], 0b00000000);
872 assert_eq!(node_features.flags[5], 0b00100000);
875 // Check that cleared flags are kept blank when converting back:
876 // - initial_routing_sync was not applicable to NodeContext
877 // - upfront_shutdown_script was cleared before converting
878 // - gossip_queries was cleared before converting
879 let features: InitFeatures = node_features.to_context_internal();
880 assert!(!features.initial_routing_sync());
881 assert!(!features.supports_upfront_shutdown_script());
882 assert!(!init_features.supports_gossip_queries());
886 fn convert_to_context_with_unknown_flags() {
887 // Ensure the `from` context has fewer known feature bytes than the `to` context.
888 assert!(InvoiceFeatures::known().flags.len() < NodeFeatures::known().flags.len());
889 let invoice_features = InvoiceFeatures::known().set_unknown_feature_optional();
890 assert!(invoice_features.supports_unknown_bits());
891 let node_features: NodeFeatures = invoice_features.to_context();
892 assert!(!node_features.supports_unknown_bits());
896 fn set_feature_bits() {
897 let features = InvoiceFeatures::empty()
898 .set_basic_mpp_optional()
899 .set_payment_secret_required();
900 assert!(features.supports_basic_mpp());
901 assert!(!features.requires_basic_mpp());
902 assert!(features.requires_payment_secret());
903 assert!(features.supports_payment_secret());
907 fn invoice_features_encoding() {
908 let features_as_u5s = vec![
909 u5::try_from_u8(6).unwrap(),
910 u5::try_from_u8(10).unwrap(),
911 u5::try_from_u8(25).unwrap(),
912 u5::try_from_u8(1).unwrap(),
913 u5::try_from_u8(10).unwrap(),
914 u5::try_from_u8(0).unwrap(),
915 u5::try_from_u8(20).unwrap(),
916 u5::try_from_u8(2).unwrap(),
917 u5::try_from_u8(0).unwrap(),
918 u5::try_from_u8(6).unwrap(),
919 u5::try_from_u8(0).unwrap(),
920 u5::try_from_u8(16).unwrap(),
921 u5::try_from_u8(1).unwrap(),
923 let features = InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
925 // Test length calculation.
926 assert_eq!(features.base32_len(), 13);
928 // Test serialization.
929 let features_serialized = features.to_base32();
930 assert_eq!(features_as_u5s, features_serialized);
932 // Test deserialization.
933 let features_deserialized = InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
934 assert_eq!(features, features_deserialized);
938 fn test_channel_type_mapping() {
939 // If we map an InvoiceFeatures with StaticRemoteKey optional, it should map into a
940 // required-StaticRemoteKey ChannelTypeFeatures.
941 let init_features = InitFeatures::empty().set_static_remote_key_optional();
942 let converted_features = ChannelTypeFeatures::from_counterparty_init(&init_features);
943 assert_eq!(converted_features, ChannelTypeFeatures::only_static_remote_key());
944 assert!(!converted_features.supports_any_optional_bits());
945 assert!(converted_features.requires_static_remote_key());