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 //! The following features are currently required in the LDK:
23 //! - `VariableLengthOnion` - requires/supports variable-length routing onion payloads
24 //! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md) for more information).
25 //! - `StaticRemoteKey` - requires/supports static key for remote output
26 //! (see [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more information).
28 //! The following features are currently supported in the LDK:
29 //! - `DataLossProtect` - requires/supports that a node which has somehow fallen behind, e.g., has been restored from an old backup,
30 //! can detect that it has fallen behind
31 //! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
32 //! - `InitialRoutingSync` - requires/supports that the sending node needs a complete routing information dump
33 //! (see [BOLT-7](https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#initial-sync) for more information).
34 //! - `UpfrontShutdownScript` - commits to a shutdown scriptpubkey when opening a channel
35 //! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
36 //! - `GossipQueries` - requires/supports more sophisticated gossip control
37 //! (see [BOLT-7](https://github.com/lightning/bolts/blob/master/07-routing-gossip.md) for more information).
38 //! - `PaymentSecret` - requires/supports that a node supports payment_secret field
39 //! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md) for more information).
40 //! - `BasicMPP` - requires/supports that a node can receive basic multi-part payments
41 //! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#basic-multi-part-payments) for more information).
42 //! - `Wumbo` - requires/supports that a node create large channels. Called `option_support_large_channel` in the spec.
43 //! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
44 //! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
45 //! and HTLC transactions are pre-signed with zero fee (see
46 //! [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
48 //! - `RouteBlinding` - requires/supports that a node can relay payments over blinded paths
49 //! (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#route-blinding) for more information).
50 //! - `ShutdownAnySegwit` - requires/supports that future segwit versions are allowed in `shutdown`
51 //! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
52 //! - `OnionMessages` - requires/supports forwarding onion messages
53 //! (see [BOLT-7](https://github.com/lightning/bolts/pull/759/files) for more information).
55 //! - `ChannelType` - node supports the channel_type field in open/accept
56 //! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
57 //! - `SCIDPrivacy` - supply channel aliases for routing
58 //! (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
59 //! - `PaymentMetadata` - include additional data in invoices which is passed to recipients in the
61 //! (see [BOLT-11](https://github.com/lightning/bolts/blob/master/11-payment-encoding.md) for
63 //! - `ZeroConf` - supports accepting HTLCs and using channels prior to funding confirmation
65 //! [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-channel_ready-message)
67 //! - `Keysend` - send funds to a node without an invoice
68 //! (see the [`Keysend` feature assignment proposal](https://github.com/lightning/bolts/issues/605#issuecomment-606679798) for more information).
69 //! - `Trampoline` - supports receiving and forwarding Trampoline payments
70 //! (see the [`Trampoline` feature proposal](https://github.com/lightning/bolts/pull/836) for more information).
72 //! LDK knows about the following features, but does not support them:
73 //! - `AnchorsNonzeroFeeHtlcTx` - the initial version of anchor outputs, which was later found to be
74 //! vulnerable (see this
75 //! [mailing list post](https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-September/002796.html)
76 //! for more information).
78 //! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
79 //! [messages]: crate::ln::msgs
81 #[allow(unused_imports)]
82 use crate::prelude::*;
84 use crate::{io, io_extras};
86 use core::borrow::Borrow;
87 use core::hash::{Hash, Hasher};
88 use core::marker::PhantomData;
91 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
92 use crate::ln::msgs::DecodeError;
93 use crate::util::ser::{Readable, WithoutLength, Writeable, Writer};
96 #[allow(unused_imports)]
97 use crate::prelude::*;
98 use crate::ln::features::Features;
100 /// The context in which [`Features`] are applicable. Defines which features are known to the
101 /// implementation, though specification of them as required or optional is up to the code
102 /// constructing a features object.
104 /// Bitmask for selecting features that are known to the implementation.
105 const KNOWN_FEATURE_MASK: &'static [u8];
108 /// Defines a [`Context`] by stating which features it requires and which are optional. Features
109 /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
110 /// feature identifiers.
111 macro_rules! define_context {
112 ($context: ident, [$( $( $known_feature: ident )|*, )*]) => {
113 #[derive(Eq, PartialEq)]
114 pub struct $context {}
116 impl Context for $context {
117 const KNOWN_FEATURE_MASK: &'static [u8] = &[
120 <Self as $known_feature>::REQUIRED_MASK |
121 <Self as $known_feature>::OPTIONAL_MASK)*,
126 impl alloc::fmt::Display for Features<$context> {
127 fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
130 fmt.write_fmt(format_args!("{}: {}, ", stringify!($known_feature),
131 if <$context as $known_feature>::requires_feature(&self.flags) { "required" }
132 else if <$context as $known_feature>::supports_feature(&self.flags) { "supported" }
133 else { "not supported" }))?;
135 {} // Rust gets mad if we only have a $()* block here, so add a dummy {}
137 fmt.write_fmt(format_args!("unknown flags: {}",
138 if self.requires_unknown_bits() { "required" }
139 else if self.supports_unknown_bits() { "supported" } else { "none" }))
145 define_context!(InitContext, [
147 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
149 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
151 BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
153 RouteBlinding | ShutdownAnySegwit | Taproot,
157 ChannelType | SCIDPrivacy,
163 define_context!(NodeContext, [
165 DataLossProtect | UpfrontShutdownScript | GossipQueries,
167 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
169 BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
171 RouteBlinding | ShutdownAnySegwit | Taproot,
175 ChannelType | SCIDPrivacy,
181 define_context!(ChannelContext, []);
182 define_context!(Bolt11InvoiceContext, [
186 VariableLengthOnion | PaymentSecret,
200 define_context!(OfferContext, []);
201 define_context!(InvoiceRequestContext, []);
202 define_context!(Bolt12InvoiceContext, [
210 define_context!(BlindedHopContext, []);
211 // This isn't a "real" feature context, and is only used in the channel_type field in an
212 // `OpenChannel` message.
213 define_context!(ChannelTypeContext, [
219 AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
230 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
231 /// useful for manipulating feature flags.
232 macro_rules! define_feature {
233 ($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/lightning/bolts/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 /// Assertion that the bits are set in the context's [`KNOWN_FEATURE_MASK`].
259 /// [`KNOWN_FEATURE_MASK`]: Context::KNOWN_FEATURE_MASK
260 #[cfg(not(test))] // We violate this constraint with `UnknownFeature`
261 const ASSERT_BITS_IN_MASK: u8;
263 /// The byte where the feature is set.
264 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
266 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
268 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
269 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
271 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
273 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
274 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
276 /// Returns whether the feature is required by the given flags.
278 fn requires_feature(flags: &Vec<u8>) -> bool {
279 flags.len() > Self::BYTE_OFFSET &&
280 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
283 /// Returns whether the feature is supported by the given flags.
285 fn supports_feature(flags: &Vec<u8>) -> bool {
286 flags.len() > Self::BYTE_OFFSET &&
287 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
290 /// Sets the feature's required (even) bit in the given flags.
292 fn set_required_bit(flags: &mut Vec<u8>) {
293 if flags.len() <= Self::BYTE_OFFSET {
294 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
297 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
298 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
301 /// Sets the feature's optional (odd) bit in the given flags.
303 fn set_optional_bit(flags: &mut Vec<u8>) {
304 if flags.len() <= Self::BYTE_OFFSET {
305 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
308 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
311 /// Clears the feature's required (even) and optional (odd) bits from the given
314 fn clear_bits(flags: &mut Vec<u8>) {
315 if flags.len() > Self::BYTE_OFFSET {
316 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
317 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
320 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
321 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
322 flags.resize(size, 0u8);
326 impl <T: $feature> Features<T> {
327 /// Set this feature as optional.
328 pub fn $optional_setter(&mut self) {
329 <T as $feature>::set_optional_bit(&mut self.flags);
332 /// Set this feature as required.
333 pub fn $required_setter(&mut self) {
334 <T as $feature>::set_required_bit(&mut self.flags);
337 /// Checks if this feature is supported.
338 pub fn $supported_getter(&self) -> bool {
339 <T as $feature>::supports_feature(&self.flags)
344 impl $feature for $context {
346 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
349 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
351 // (byte & (REQUIRED_MASK | OPTIONAL_MASK)) >> (EVEN_BIT % 8) == 3
352 #[cfg(not(test))] // We violate this constraint with `UnknownFeature`
353 const ASSERT_BITS_IN_MASK: u8 =
354 ((<$context>::KNOWN_FEATURE_MASK[<Self as $feature>::BYTE_OFFSET] & (<Self as $feature>::REQUIRED_MASK | <Self as $feature>::OPTIONAL_MASK))
355 >> (<Self as $feature>::EVEN_BIT % 8)) - 3;
359 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
360 $required_setter: ident, $supported_getter: ident, $required_getter: ident) => {
361 define_feature!($odd_bit, $feature, [$($context),+], $doc, $optional_setter, $required_setter, $supported_getter);
362 impl <T: $feature> Features<T> {
363 /// Checks if this feature is required.
364 pub fn $required_getter(&self) -> bool {
365 <T as $feature>::requires_feature(&self.flags)
371 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
372 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
373 set_data_loss_protect_required, supports_data_loss_protect, requires_data_loss_protect);
374 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
375 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
376 set_initial_routing_sync_optional, set_initial_routing_sync_required,
377 initial_routing_sync);
378 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
379 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
380 set_upfront_shutdown_script_required, supports_upfront_shutdown_script,
381 requires_upfront_shutdown_script);
382 define_feature!(7, GossipQueries, [InitContext, NodeContext],
383 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required,
384 supports_gossip_queries, requires_gossip_queries);
385 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, Bolt11InvoiceContext],
386 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
387 set_variable_length_onion_required, supports_variable_length_onion,
388 requires_variable_length_onion);
389 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext, ChannelTypeContext],
390 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
391 set_static_remote_key_required, supports_static_remote_key, requires_static_remote_key);
392 define_feature!(15, PaymentSecret, [InitContext, NodeContext, Bolt11InvoiceContext],
393 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required,
394 supports_payment_secret, requires_payment_secret);
395 define_feature!(17, BasicMPP, [InitContext, NodeContext, Bolt11InvoiceContext, Bolt12InvoiceContext],
396 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
397 supports_basic_mpp, requires_basic_mpp);
398 define_feature!(19, Wumbo, [InitContext, NodeContext],
399 "Feature flags for `option_support_large_channel` (aka wumbo channels).", set_wumbo_optional, set_wumbo_required,
400 supports_wumbo, requires_wumbo);
401 define_feature!(21, AnchorsNonzeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
402 "Feature flags for `option_anchors_nonzero_fee_htlc_tx`.", set_anchors_nonzero_fee_htlc_tx_optional,
403 set_anchors_nonzero_fee_htlc_tx_required, supports_anchors_nonzero_fee_htlc_tx, requires_anchors_nonzero_fee_htlc_tx);
404 define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
405 "Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
406 set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
407 define_feature!(25, RouteBlinding, [InitContext, NodeContext],
408 "Feature flags for `option_route_blinding`.", set_route_blinding_optional,
409 set_route_blinding_required, supports_route_blinding, requires_route_blinding);
410 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
411 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
412 set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
413 define_feature!(31, Taproot, [InitContext, NodeContext, ChannelTypeContext],
414 "Feature flags for `option_taproot`.", set_taproot_optional,
415 set_taproot_required, supports_taproot, requires_taproot);
416 define_feature!(39, OnionMessages, [InitContext, NodeContext],
417 "Feature flags for `option_onion_messages`.", set_onion_messages_optional,
418 set_onion_messages_required, supports_onion_messages, requires_onion_messages);
419 define_feature!(45, ChannelType, [InitContext, NodeContext],
420 "Feature flags for `option_channel_type`.", set_channel_type_optional,
421 set_channel_type_required, supports_channel_type, requires_channel_type);
422 define_feature!(47, SCIDPrivacy, [InitContext, NodeContext, ChannelTypeContext],
423 "Feature flags for only forwarding with SCID aliasing. Called `option_scid_alias` in the BOLTs",
424 set_scid_privacy_optional, set_scid_privacy_required, supports_scid_privacy, requires_scid_privacy);
425 define_feature!(49, PaymentMetadata, [Bolt11InvoiceContext],
426 "Feature flags for payment metadata in invoices.", set_payment_metadata_optional,
427 set_payment_metadata_required, supports_payment_metadata, requires_payment_metadata);
428 define_feature!(51, ZeroConf, [InitContext, NodeContext, ChannelTypeContext],
429 "Feature flags for accepting channels with zero confirmations. Called `option_zeroconf` in the BOLTs",
430 set_zero_conf_optional, set_zero_conf_required, supports_zero_conf, requires_zero_conf);
431 define_feature!(55, Keysend, [NodeContext],
432 "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
433 supports_keysend, requires_keysend);
434 define_feature!(57, Trampoline, [InitContext, NodeContext, Bolt11InvoiceContext],
435 "Feature flags for Trampoline routing.", set_trampoline_routing_optional, set_trampoline_routing_required,
436 supports_trampoline_routing, requires_trampoline_routing);
437 // Note: update the module-level docs when a new feature bit is added!
440 define_feature!(123456789, UnknownFeature,
441 [NodeContext, ChannelContext, Bolt11InvoiceContext, OfferContext, InvoiceRequestContext, Bolt12InvoiceContext, BlindedHopContext],
442 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
443 set_unknown_feature_required, supports_unknown_test_feature, requires_unknown_test_feature);
446 /// Tracks the set of features which a node implements, templated by the context in which it
449 /// This is not exported to bindings users as we map the concrete feature types below directly instead
451 pub struct Features<T: sealed::Context> {
452 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
454 mark: PhantomData<T>,
457 impl<T: sealed::Context, Rhs: Borrow<Self>> core::ops::BitOrAssign<Rhs> for Features<T> {
458 fn bitor_assign(&mut self, rhs: Rhs) {
459 let total_feature_len = cmp::max(self.flags.len(), rhs.borrow().flags.len());
460 self.flags.resize(total_feature_len, 0u8);
461 for (byte, rhs_byte) in self.flags.iter_mut().zip(rhs.borrow().flags.iter()) {
467 impl<T: sealed::Context> core::ops::BitOr for Features<T> {
470 fn bitor(mut self, o: Self) -> Self {
476 impl<T: sealed::Context> Clone for Features<T> {
477 fn clone(&self) -> Self {
479 flags: self.flags.clone(),
484 impl<T: sealed::Context> Hash for Features<T> {
485 fn hash<H: Hasher>(&self, hasher: &mut H) {
486 let mut nonzero_flags = &self.flags[..];
487 while nonzero_flags.last() == Some(&0) {
488 nonzero_flags = &nonzero_flags[..nonzero_flags.len() - 1];
490 nonzero_flags.hash(hasher);
493 impl<T: sealed::Context> PartialEq for Features<T> {
494 fn eq(&self, o: &Self) -> bool {
495 let mut o_iter = o.flags.iter();
496 let mut self_iter = self.flags.iter();
498 match (o_iter.next(), self_iter.next()) {
499 (Some(o), Some(us)) => if o != us { return false },
500 (Some(b), None) | (None, Some(b)) => if *b != 0 { return false },
501 (None, None) => return true,
506 impl<T: sealed::Context> PartialOrd for Features<T> {
507 fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
508 self.flags.partial_cmp(&other.flags)
511 impl<T: sealed::Context + Eq> Ord for Features<T> {
512 fn cmp(&self, other: &Self) -> cmp::Ordering {
513 self.flags.cmp(&other.flags)
516 impl<T: sealed::Context> fmt::Debug for Features<T> {
517 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
522 /// Features used within an `init` message.
523 pub type InitFeatures = Features<sealed::InitContext>;
524 /// Features used within a `node_announcement` message.
525 pub type NodeFeatures = Features<sealed::NodeContext>;
526 /// Features used within a `channel_announcement` message.
527 pub type ChannelFeatures = Features<sealed::ChannelContext>;
528 /// Features used within an invoice.
529 pub type Bolt11InvoiceFeatures = Features<sealed::Bolt11InvoiceContext>;
530 /// Features used within an `offer`.
531 pub type OfferFeatures = Features<sealed::OfferContext>;
532 /// Features used within an `invoice_request`.
533 pub type InvoiceRequestFeatures = Features<sealed::InvoiceRequestContext>;
534 /// Features used within an `invoice`.
535 pub type Bolt12InvoiceFeatures = Features<sealed::Bolt12InvoiceContext>;
536 /// Features used within BOLT 4 encrypted_data_tlv and BOLT 12 blinded_payinfo
537 pub type BlindedHopFeatures = Features<sealed::BlindedHopContext>;
539 /// Features used within the channel_type field in an OpenChannel message.
541 /// A channel is always of some known "type", describing the transaction formats used and the exact
542 /// semantics of our interaction with our peer.
544 /// Note that because a channel is a specific type which is proposed by the opener and accepted by
545 /// the counterparty, only required features are allowed here.
547 /// This is serialized differently from other feature types - it is not prefixed by a length, and
548 /// thus must only appear inside a TLV where its length is known in advance.
549 pub type ChannelTypeFeatures = Features<sealed::ChannelTypeContext>;
552 /// Writes all features present up to, and including, 13.
553 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
554 let len = cmp::min(2, self.flags.len());
555 (len as u16).write(w)?;
556 for i in (0..len).rev() {
558 self.flags[i].write(w)?;
560 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
561 // up-to-and-including-bit-5, 0-indexed, on this byte:
562 (self.flags[i] & 0b00_11_11_11).write(w)?;
568 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
569 /// are included in the result.
570 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
571 self.to_context_internal()
575 impl Bolt11InvoiceFeatures {
576 /// Converts `Bolt11InvoiceFeatures` to `Features<C>`. Only known `Bolt11InvoiceFeatures` relevant to
577 /// context `C` are included in the result.
578 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
579 self.to_context_internal()
582 /// Getting a route for a keysend payment to a private node requires providing the payee's
583 /// features (since they were not announced in a node announcement). However, keysend payments
584 /// don't have an invoice to pull the payee's features from, so this method is provided for use in
585 /// [`PaymentParameters::for_keysend`], thus omitting the need for payers to manually construct an
586 /// `Bolt11InvoiceFeatures` for [`find_route`].
588 /// MPP keysend is not widely supported yet, so we parameterize support to allow the user to
589 /// choose whether their router should find multi-part routes.
591 /// [`PaymentParameters::for_keysend`]: crate::routing::router::PaymentParameters::for_keysend
592 /// [`find_route`]: crate::routing::router::find_route
593 pub(crate) fn for_keysend(allow_mpp: bool) -> Bolt11InvoiceFeatures {
594 let mut res = Bolt11InvoiceFeatures::empty();
595 res.set_variable_length_onion_optional();
597 res.set_basic_mpp_optional();
603 impl Bolt12InvoiceFeatures {
604 /// Converts [`Bolt12InvoiceFeatures`] to [`Features<C>`]. Only known [`Bolt12InvoiceFeatures`]
605 /// relevant to context `C` are included in the result.
606 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
607 self.to_context_internal()
611 impl ChannelTypeFeatures {
612 // Maps the relevant `InitFeatures` to `ChannelTypeFeatures`. Any unknown features to
613 // `ChannelTypeFeatures` are not included in the result.
614 pub(crate) fn from_init(init: &InitFeatures) -> Self {
615 let mut ret = init.to_context_internal();
616 // ChannelTypeFeatures must only contain required bits, so we OR the required forms of all
617 // optional bits and then AND out the optional ones.
618 for byte in ret.flags.iter_mut() {
619 *byte |= (*byte & 0b10_10_10_10) >> 1;
620 *byte &= 0b01_01_01_01;
625 /// Constructs a ChannelTypeFeatures with only static_remotekey set
626 pub(crate) fn only_static_remote_key() -> Self {
627 let mut ret = Self::empty();
628 <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
632 /// Constructs a ChannelTypeFeatures with anchors support
633 pub(crate) fn anchors_zero_htlc_fee_and_dependencies() -> Self {
634 let mut ret = Self::empty();
635 <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
636 <sealed::ChannelTypeContext as sealed::AnchorsZeroFeeHtlcTx>::set_required_bit(&mut ret.flags);
641 impl ToBase32 for Bolt11InvoiceFeatures {
642 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
643 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
644 // minus one before dividing
645 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
646 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
647 for (byte_idx, byte) in self.flags.iter().enumerate() {
648 let bit_pos_from_left_0_indexed = byte_idx * 8;
649 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
650 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
651 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
652 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
653 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
655 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
656 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
659 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
660 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
663 // Trim the highest feature bits.
664 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
667 writer.write(&res_u5s)
671 impl Base32Len for Bolt11InvoiceFeatures {
672 fn base32_len(&self) -> usize {
673 self.to_base32().len()
677 impl FromBase32 for Bolt11InvoiceFeatures {
678 type Err = bech32::Error;
680 fn from_base32(field_data: &[u5]) -> Result<Bolt11InvoiceFeatures, bech32::Error> {
681 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
682 // minus one before dividing
683 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
684 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
685 for (u5_idx, chunk) in field_data.iter().enumerate() {
686 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
687 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
688 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
689 let chunk_u16 = chunk.to_u8() as u16;
690 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
691 if new_byte_idx != length_bytes - 1 {
692 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
695 // Trim the highest feature bits.
696 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
699 Ok(Bolt11InvoiceFeatures::from_le_bytes(res_bytes))
703 impl<T: sealed::Context> Features<T> {
704 /// Create a blank Features with no features set
705 pub fn empty() -> Self {
712 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
713 /// included in the result.
714 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
715 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
716 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
717 let mut flags = Vec::new();
718 for (i, byte) in self.flags.iter().enumerate() {
719 if i < from_byte_count && i < to_byte_count {
720 let from_known_features = T::KNOWN_FEATURE_MASK[i];
721 let to_known_features = C::KNOWN_FEATURE_MASK[i];
722 flags.push(byte & from_known_features & to_known_features);
725 Features::<C> { flags, mark: PhantomData, }
728 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
729 /// most on-the-wire encodings.
731 /// This is not exported to bindings users as we don't support export across multiple T
732 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
740 /// Gets the underlying flags set, in LE.
741 pub fn le_flags(&self) -> &Vec<u8> {
745 fn write_be<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
746 for f in self.flags.iter().rev() { // Swap back to big-endian
752 /// Create a [`Features`] given a set of flags, in big-endian. This is in byte order from
753 /// most on-the-wire encodings.
755 /// This is not exported to bindings users as we don't support export across multiple T
756 pub fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
757 flags.reverse(); // Swap to little-endian
764 pub(crate) fn supports_any_optional_bits(&self) -> bool {
765 self.flags.iter().any(|&byte| (byte & 0b10_10_10_10) != 0)
768 /// Returns true if this `Features` object contains required features unknown by `other`.
769 pub fn requires_unknown_bits_from(&self, other: &Self) -> bool {
770 // Bitwise AND-ing with all even bits set except for known features will select required
772 self.flags.iter().enumerate().any(|(i, &byte)| {
773 const REQUIRED_FEATURES: u8 = 0b01_01_01_01;
774 const OPTIONAL_FEATURES: u8 = 0b10_10_10_10;
775 let unknown_features = if i < other.flags.len() {
776 // Form a mask similar to !T::KNOWN_FEATURE_MASK only for `other`
778 | ((other.flags[i] >> 1) & REQUIRED_FEATURES)
779 | ((other.flags[i] << 1) & OPTIONAL_FEATURES))
783 (byte & (REQUIRED_FEATURES & unknown_features)) != 0
787 /// Returns true if this `Features` object contains unknown feature flags which are set as
789 pub fn requires_unknown_bits(&self) -> bool {
790 // Bitwise AND-ing with all even bits set except for known features will select required
792 let byte_count = T::KNOWN_FEATURE_MASK.len();
793 self.flags.iter().enumerate().any(|(i, &byte)| {
794 let required_features = 0b01_01_01_01;
795 let unknown_features = if i < byte_count {
796 !T::KNOWN_FEATURE_MASK[i]
800 (byte & (required_features & unknown_features)) != 0
804 pub(crate) fn supports_unknown_bits(&self) -> bool {
805 // Bitwise AND-ing with all even and odd bits set except for known features will select
806 // both required and optional unknown features.
807 let byte_count = T::KNOWN_FEATURE_MASK.len();
808 self.flags.iter().enumerate().any(|(i, &byte)| {
809 let unknown_features = if i < byte_count {
810 !T::KNOWN_FEATURE_MASK[i]
814 (byte & unknown_features) != 0
818 // Returns true if the features within `self` are a subset of the features within `other`.
819 pub(crate) fn is_subset(&self, other: &Self) -> bool {
820 for (idx, byte) in self.flags.iter().enumerate() {
821 if let Some(other_byte) = other.flags.get(idx) {
822 if byte & other_byte != *byte {
823 // `self` has bits set that `other` doesn't.
828 // `self` has a non-zero byte that `other` doesn't.
836 /// Sets a required feature bit. Errors if `bit` is outside the feature range as defined
839 /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
840 /// be set instead (i.e., `bit - 1`).
842 /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
843 pub fn set_required_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
844 self.set_feature_bit(bit - (bit % 2))
847 /// Sets an optional feature bit. Errors if `bit` is outside the feature range as defined
850 /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
851 /// set instead (i.e., `bit + 1`).
853 /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
854 pub fn set_optional_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
855 self.set_feature_bit(bit + (1 - (bit % 2)))
858 fn set_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
862 self.set_bit(bit, false)
865 /// Sets a required custom feature bit. Errors if `bit` is outside the custom range as defined
866 /// by [bLIP 2] or if it is a known `T` feature.
868 /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
869 /// be set instead (i.e., `bit - 1`).
871 /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
872 pub fn set_required_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
873 self.set_custom_bit(bit - (bit % 2))
876 /// Sets an optional custom feature bit. Errors if `bit` is outside the custom range as defined
877 /// by [bLIP 2] or if it is a known `T` feature.
879 /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
880 /// set instead (i.e., `bit + 1`).
882 /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
883 pub fn set_optional_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
884 self.set_custom_bit(bit + (1 - (bit % 2)))
887 fn set_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
891 self.set_bit(bit, true)
894 fn set_bit(&mut self, bit: usize, custom: bool) -> Result<(), ()> {
895 let byte_offset = bit / 8;
896 let mask = 1 << (bit - 8 * byte_offset);
897 if byte_offset < T::KNOWN_FEATURE_MASK.len() && custom {
898 if (T::KNOWN_FEATURE_MASK[byte_offset] & mask) != 0 {
903 if self.flags.len() <= byte_offset {
904 self.flags.resize(byte_offset + 1, 0u8);
907 self.flags[byte_offset] |= mask;
913 impl<T: sealed::UpfrontShutdownScript> Features<T> {
915 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
916 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
921 impl<T: sealed::ShutdownAnySegwit> Features<T> {
923 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
924 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
929 impl<T: sealed::Wumbo> Features<T> {
931 pub(crate) fn clear_wumbo(mut self) -> Self {
932 <T as sealed::Wumbo>::clear_bits(&mut self.flags);
937 impl<T: sealed::SCIDPrivacy> Features<T> {
938 pub(crate) fn clear_scid_privacy(&mut self) {
939 <T as sealed::SCIDPrivacy>::clear_bits(&mut self.flags);
943 impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
944 pub(crate) fn clear_anchors_zero_fee_htlc_tx(&mut self) {
945 <T as sealed::AnchorsZeroFeeHtlcTx>::clear_bits(&mut self.flags);
949 impl<T: sealed::RouteBlinding> Features<T> {
951 pub(crate) fn clear_route_blinding(&mut self) {
952 <T as sealed::RouteBlinding>::clear_bits(&mut self.flags);
957 impl<T: sealed::UnknownFeature> Features<T> {
958 pub(crate) fn unknown() -> Self {
959 let mut features = Self::empty();
960 features.set_unknown_feature_required();
965 macro_rules! impl_feature_len_prefixed_write {
966 ($features: ident) => {
967 impl Writeable for $features {
968 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
969 (self.flags.len() as u16).write(w)?;
973 impl Readable for $features {
974 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
975 Ok(Self::from_be_bytes(Vec::<u8>::read(r)?))
980 impl_feature_len_prefixed_write!(InitFeatures);
981 impl_feature_len_prefixed_write!(ChannelFeatures);
982 impl_feature_len_prefixed_write!(NodeFeatures);
983 impl_feature_len_prefixed_write!(Bolt11InvoiceFeatures);
984 impl_feature_len_prefixed_write!(Bolt12InvoiceFeatures);
985 impl_feature_len_prefixed_write!(BlindedHopFeatures);
987 // Some features only appear inside of TLVs, so they don't have a length prefix when serialized.
988 macro_rules! impl_feature_tlv_write {
989 ($features: ident) => {
990 impl Writeable for $features {
991 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
992 WithoutLength(self).write(w)
995 impl Readable for $features {
996 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
997 Ok(WithoutLength::<Self>::read(r)?.0)
1003 impl_feature_tlv_write!(ChannelTypeFeatures);
1005 // Some features may appear both in a TLV record and as part of a TLV subtype sequence. The latter
1006 // requires a length but the former does not.
1008 impl<T: sealed::Context> Writeable for WithoutLength<&Features<T>> {
1009 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1014 impl<T: sealed::Context> Readable for WithoutLength<Features<T>> {
1015 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
1016 let v = io_extras::read_to_end(r)?;
1017 Ok(WithoutLength(Features::<T>::from_be_bytes(v)))
1023 use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, Bolt11InvoiceFeatures, NodeFeatures, OfferFeatures, sealed};
1024 use bitcoin::bech32::{Base32Len, FromBase32, ToBase32, u5};
1025 use crate::util::ser::{Readable, WithoutLength, Writeable};
1028 fn sanity_test_unknown_bits() {
1029 let features = ChannelFeatures::empty();
1030 assert!(!features.requires_unknown_bits());
1031 assert!(!features.supports_unknown_bits());
1033 let mut features = ChannelFeatures::empty();
1034 features.set_unknown_feature_required();
1035 assert!(features.requires_unknown_bits());
1036 assert!(features.supports_unknown_bits());
1038 let mut features = ChannelFeatures::empty();
1039 features.set_unknown_feature_optional();
1040 assert!(!features.requires_unknown_bits());
1041 assert!(features.supports_unknown_bits());
1045 fn requires_unknown_bits_from() {
1046 let mut features1 = InitFeatures::empty();
1047 let mut features2 = InitFeatures::empty();
1048 assert!(!features1.requires_unknown_bits_from(&features2));
1049 assert!(!features2.requires_unknown_bits_from(&features1));
1051 features1.set_data_loss_protect_required();
1052 assert!(features1.requires_unknown_bits_from(&features2));
1053 assert!(!features2.requires_unknown_bits_from(&features1));
1055 features2.set_data_loss_protect_optional();
1056 assert!(!features1.requires_unknown_bits_from(&features2));
1057 assert!(!features2.requires_unknown_bits_from(&features1));
1059 features2.set_gossip_queries_required();
1060 assert!(!features1.requires_unknown_bits_from(&features2));
1061 assert!(features2.requires_unknown_bits_from(&features1));
1063 features1.set_gossip_queries_optional();
1064 assert!(!features1.requires_unknown_bits_from(&features2));
1065 assert!(!features2.requires_unknown_bits_from(&features1));
1067 features1.set_variable_length_onion_required();
1068 assert!(features1.requires_unknown_bits_from(&features2));
1069 assert!(!features2.requires_unknown_bits_from(&features1));
1071 features2.set_variable_length_onion_optional();
1072 assert!(!features1.requires_unknown_bits_from(&features2));
1073 assert!(!features2.requires_unknown_bits_from(&features1));
1075 features1.set_basic_mpp_required();
1076 features2.set_wumbo_required();
1077 assert!(features1.requires_unknown_bits_from(&features2));
1078 assert!(features2.requires_unknown_bits_from(&features1));
1082 fn convert_to_context_with_relevant_flags() {
1083 let mut init_features = InitFeatures::empty();
1084 // Set a bunch of features we use, plus initial_routing_sync_required (which shouldn't get
1085 // converted as it's only relevant in an init context).
1086 init_features.set_initial_routing_sync_required();
1087 init_features.set_data_loss_protect_required();
1088 init_features.set_variable_length_onion_required();
1089 init_features.set_static_remote_key_required();
1090 init_features.set_payment_secret_required();
1091 init_features.set_basic_mpp_optional();
1092 init_features.set_wumbo_optional();
1093 init_features.set_anchors_zero_fee_htlc_tx_optional();
1094 init_features.set_route_blinding_optional();
1095 init_features.set_shutdown_any_segwit_optional();
1096 init_features.set_onion_messages_optional();
1097 init_features.set_channel_type_optional();
1098 init_features.set_scid_privacy_optional();
1099 init_features.set_zero_conf_optional();
1101 assert!(init_features.initial_routing_sync());
1102 assert!(!init_features.supports_upfront_shutdown_script());
1103 assert!(!init_features.supports_gossip_queries());
1105 let node_features: NodeFeatures = init_features.to_context();
1107 // Check that the flags are as expected:
1108 // - option_data_loss_protect (req)
1109 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
1110 // - basic_mpp | wumbo | option_anchors_zero_fee_htlc_tx
1111 // - option_route_blinding | opt_shutdown_anysegwit
1113 // - option_channel_type | option_scid_alias
1114 // - option_zeroconf
1115 assert_eq!(node_features.flags.len(), 7);
1116 assert_eq!(node_features.flags[0], 0b00000001);
1117 assert_eq!(node_features.flags[1], 0b01010001);
1118 assert_eq!(node_features.flags[2], 0b10001010);
1119 assert_eq!(node_features.flags[3], 0b00001010);
1120 assert_eq!(node_features.flags[4], 0b10000000);
1121 assert_eq!(node_features.flags[5], 0b10100000);
1122 assert_eq!(node_features.flags[6], 0b00001000);
1125 // Check that cleared flags are kept blank when converting back:
1126 // - initial_routing_sync was not applicable to NodeContext
1127 // - upfront_shutdown_script was cleared before converting
1128 // - gossip_queries was cleared before converting
1129 let features: InitFeatures = node_features.to_context_internal();
1130 assert!(!features.initial_routing_sync());
1131 assert!(!features.supports_upfront_shutdown_script());
1132 assert!(!init_features.supports_gossip_queries());
1136 fn convert_to_context_with_unknown_flags() {
1137 // Ensure the `from` context has fewer known feature bytes than the `to` context.
1138 assert!(<sealed::ChannelContext as sealed::Context>::KNOWN_FEATURE_MASK.len() <
1139 <sealed::Bolt11InvoiceContext as sealed::Context>::KNOWN_FEATURE_MASK.len());
1140 let mut channel_features = ChannelFeatures::empty();
1141 channel_features.set_unknown_feature_optional();
1142 assert!(channel_features.supports_unknown_bits());
1143 let invoice_features: Bolt11InvoiceFeatures = channel_features.to_context_internal();
1144 assert!(!invoice_features.supports_unknown_bits());
1148 fn set_feature_bits() {
1149 let mut features = Bolt11InvoiceFeatures::empty();
1150 features.set_basic_mpp_optional();
1151 features.set_payment_secret_required();
1152 assert!(features.supports_basic_mpp());
1153 assert!(!features.requires_basic_mpp());
1154 assert!(features.requires_payment_secret());
1155 assert!(features.supports_payment_secret());
1157 // Set flags manually
1158 let mut features = NodeFeatures::empty();
1159 assert!(features.set_optional_feature_bit(55).is_ok());
1160 assert!(features.supports_keysend());
1161 assert!(features.set_optional_feature_bit(255).is_ok());
1162 assert!(features.set_required_feature_bit(256).is_err());
1166 fn set_custom_bits() {
1167 let mut features = Bolt11InvoiceFeatures::empty();
1168 features.set_variable_length_onion_optional();
1169 assert_eq!(features.flags[1], 0b00000010);
1171 assert!(features.set_optional_custom_bit(255).is_err());
1172 assert!(features.set_required_custom_bit(256).is_ok());
1173 assert!(features.set_required_custom_bit(258).is_ok());
1174 assert_eq!(features.flags[31], 0b00000000);
1175 assert_eq!(features.flags[32], 0b00000101);
1177 let known_bit = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::EVEN_BIT;
1178 let byte_offset = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::BYTE_OFFSET;
1179 assert_eq!(byte_offset, 1);
1180 assert_eq!(features.flags[byte_offset], 0b00000010);
1181 assert!(features.set_required_custom_bit(known_bit).is_err());
1182 assert_eq!(features.flags[byte_offset], 0b00000010);
1184 let mut features = Bolt11InvoiceFeatures::empty();
1185 assert!(features.set_optional_custom_bit(256).is_ok());
1186 assert!(features.set_optional_custom_bit(259).is_ok());
1187 assert_eq!(features.flags[32], 0b00001010);
1189 let mut features = Bolt11InvoiceFeatures::empty();
1190 assert!(features.set_required_custom_bit(257).is_ok());
1191 assert!(features.set_required_custom_bit(258).is_ok());
1192 assert_eq!(features.flags[32], 0b00000101);
1196 fn encodes_features_without_length() {
1197 let features = OfferFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
1198 assert_eq!(features.flags.len(), 8);
1200 let mut serialized_features = Vec::new();
1201 WithoutLength(&features).write(&mut serialized_features).unwrap();
1202 assert_eq!(serialized_features.len(), 8);
1204 let deserialized_features =
1205 WithoutLength::<OfferFeatures>::read(&mut &serialized_features[..]).unwrap().0;
1206 assert_eq!(features, deserialized_features);
1210 fn invoice_features_encoding() {
1211 let features_as_u5s = vec![
1212 u5::try_from_u8(6).unwrap(),
1213 u5::try_from_u8(10).unwrap(),
1214 u5::try_from_u8(25).unwrap(),
1215 u5::try_from_u8(1).unwrap(),
1216 u5::try_from_u8(10).unwrap(),
1217 u5::try_from_u8(0).unwrap(),
1218 u5::try_from_u8(20).unwrap(),
1219 u5::try_from_u8(2).unwrap(),
1220 u5::try_from_u8(0).unwrap(),
1221 u5::try_from_u8(6).unwrap(),
1222 u5::try_from_u8(0).unwrap(),
1223 u5::try_from_u8(16).unwrap(),
1224 u5::try_from_u8(1).unwrap(),
1226 let features = Bolt11InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
1228 // Test length calculation.
1229 assert_eq!(features.base32_len(), 13);
1231 // Test serialization.
1232 let features_serialized = features.to_base32();
1233 assert_eq!(features_as_u5s, features_serialized);
1235 // Test deserialization.
1236 let features_deserialized = Bolt11InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
1237 assert_eq!(features, features_deserialized);
1241 fn test_channel_type_mapping() {
1242 // If we map an Bolt11InvoiceFeatures with StaticRemoteKey optional, it should map into a
1243 // required-StaticRemoteKey ChannelTypeFeatures.
1244 let mut init_features = InitFeatures::empty();
1245 init_features.set_static_remote_key_optional();
1246 let converted_features = ChannelTypeFeatures::from_init(&init_features);
1247 assert_eq!(converted_features, ChannelTypeFeatures::only_static_remote_key());
1248 assert!(!converted_features.supports_any_optional_bits());
1249 assert!(converted_features.requires_static_remote_key());
1253 #[cfg(feature = "std")]
1254 fn test_excess_zero_bytes_ignored() {
1255 // Checks that `Hash` and `PartialEq` ignore excess zero bytes, which may appear due to
1256 // feature conversion or because a peer serialized their feature poorly.
1257 use std::collections::hash_map::DefaultHasher;
1258 use std::hash::{Hash, Hasher};
1260 let mut zerod_features = InitFeatures::empty();
1261 zerod_features.flags = vec![0];
1262 let empty_features = InitFeatures::empty();
1263 assert!(empty_features.flags.is_empty());
1265 assert_eq!(zerod_features, empty_features);
1267 let mut zerod_hash = DefaultHasher::new();
1268 zerod_features.hash(&mut zerod_hash);
1269 let mut empty_hash = DefaultHasher::new();
1270 empty_features.hash(&mut empty_hash);
1271 assert_eq!(zerod_hash.finish(), empty_hash.finish());