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;
90 use bech32::{Base32Len, FromBase32, ToBase32, u5, WriteBase32};
91 use crate::ln::msgs::DecodeError;
92 use crate::util::ser::{Readable, WithoutLength, Writeable, Writer};
95 #[allow(unused_imports)]
96 use crate::prelude::*;
97 use crate::ln::features::Features;
99 /// The context in which [`Features`] are applicable. Defines which features are known to the
100 /// implementation, though specification of them as required or optional is up to the code
101 /// constructing a features object.
103 /// Bitmask for selecting features that are known to the implementation.
104 const KNOWN_FEATURE_MASK: &'static [u8];
107 /// Defines a [`Context`] by stating which features it requires and which are optional. Features
108 /// are specified as a comma-separated list of bytes where each byte is a pipe-delimited list of
109 /// feature identifiers.
110 macro_rules! define_context {
111 ($context: ident, [$( $( $known_feature: ident )|*, )*]) => {
112 #[derive(Eq, PartialEq)]
113 pub struct $context {}
115 impl Context for $context {
116 const KNOWN_FEATURE_MASK: &'static [u8] = &[
119 <Self as $known_feature>::REQUIRED_MASK |
120 <Self as $known_feature>::OPTIONAL_MASK)*,
125 impl alloc::fmt::Display for Features<$context> {
126 fn fmt(&self, fmt: &mut alloc::fmt::Formatter) -> Result<(), alloc::fmt::Error> {
129 fmt.write_fmt(format_args!("{}: {}, ", stringify!($known_feature),
130 if <$context as $known_feature>::requires_feature(&self.flags) { "required" }
131 else if <$context as $known_feature>::supports_feature(&self.flags) { "supported" }
132 else { "not supported" }))?;
134 {} // Rust gets mad if we only have a $()* block here, so add a dummy {}
136 fmt.write_fmt(format_args!("unknown flags: {}",
137 if self.requires_unknown_bits() { "required" }
138 else if self.supports_unknown_bits() { "supported" } else { "none" }))
144 define_context!(InitContext, [
146 DataLossProtect | InitialRoutingSync | UpfrontShutdownScript | GossipQueries,
148 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
150 BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
152 RouteBlinding | ShutdownAnySegwit | Taproot,
156 ChannelType | SCIDPrivacy,
162 define_context!(NodeContext, [
164 DataLossProtect | UpfrontShutdownScript | GossipQueries,
166 VariableLengthOnion | StaticRemoteKey | PaymentSecret,
168 BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
170 RouteBlinding | ShutdownAnySegwit | Taproot,
174 ChannelType | SCIDPrivacy,
180 define_context!(ChannelContext, []);
181 define_context!(Bolt11InvoiceContext, [
185 VariableLengthOnion | PaymentSecret,
199 define_context!(OfferContext, []);
200 define_context!(InvoiceRequestContext, []);
201 define_context!(Bolt12InvoiceContext, [
209 define_context!(BlindedHopContext, []);
210 // This isn't a "real" feature context, and is only used in the channel_type field in an
211 // `OpenChannel` message.
212 define_context!(ChannelTypeContext, [
218 AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
229 /// Defines a feature with the given bits for the specified [`Context`]s. The generated trait is
230 /// useful for manipulating feature flags.
231 macro_rules! define_feature {
232 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
233 $required_setter: ident, $supported_getter: ident) => {
236 /// See [BOLT #9] for details.
238 /// [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
239 pub trait $feature: Context {
240 /// The bit used to signify that the feature is required.
241 const EVEN_BIT: usize = $odd_bit - 1;
243 /// The bit used to signify that the feature is optional.
244 const ODD_BIT: usize = $odd_bit;
246 /// Assertion that [`EVEN_BIT`] is actually even.
248 /// [`EVEN_BIT`]: #associatedconstant.EVEN_BIT
249 const ASSERT_EVEN_BIT_PARITY: usize;
251 /// Assertion that [`ODD_BIT`] is actually odd.
253 /// [`ODD_BIT`]: #associatedconstant.ODD_BIT
254 const ASSERT_ODD_BIT_PARITY: usize;
256 /// Assertion that the bits are set in the context's [`KNOWN_FEATURE_MASK`].
258 /// [`KNOWN_FEATURE_MASK`]: Context::KNOWN_FEATURE_MASK
259 #[cfg(not(test))] // We violate this constraint with `UnknownFeature`
260 const ASSERT_BITS_IN_MASK: u8;
262 /// The byte where the feature is set.
263 const BYTE_OFFSET: usize = Self::EVEN_BIT / 8;
265 /// The bitmask for the feature's required flag relative to the [`BYTE_OFFSET`].
267 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
268 const REQUIRED_MASK: u8 = 1 << (Self::EVEN_BIT - 8 * Self::BYTE_OFFSET);
270 /// The bitmask for the feature's optional flag relative to the [`BYTE_OFFSET`].
272 /// [`BYTE_OFFSET`]: #associatedconstant.BYTE_OFFSET
273 const OPTIONAL_MASK: u8 = 1 << (Self::ODD_BIT - 8 * Self::BYTE_OFFSET);
275 /// Returns whether the feature is required by the given flags.
277 fn requires_feature(flags: &Vec<u8>) -> bool {
278 flags.len() > Self::BYTE_OFFSET &&
279 (flags[Self::BYTE_OFFSET] & Self::REQUIRED_MASK) != 0
282 /// Returns whether the feature is supported by the given flags.
284 fn supports_feature(flags: &Vec<u8>) -> bool {
285 flags.len() > Self::BYTE_OFFSET &&
286 (flags[Self::BYTE_OFFSET] & (Self::REQUIRED_MASK | Self::OPTIONAL_MASK)) != 0
289 /// Sets the feature's required (even) bit in the given flags.
291 fn set_required_bit(flags: &mut Vec<u8>) {
292 if flags.len() <= Self::BYTE_OFFSET {
293 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
296 flags[Self::BYTE_OFFSET] |= Self::REQUIRED_MASK;
297 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
300 /// Sets the feature's optional (odd) bit in the given flags.
302 fn set_optional_bit(flags: &mut Vec<u8>) {
303 if flags.len() <= Self::BYTE_OFFSET {
304 flags.resize(Self::BYTE_OFFSET + 1, 0u8);
307 flags[Self::BYTE_OFFSET] |= Self::OPTIONAL_MASK;
310 /// Clears the feature's required (even) and optional (odd) bits from the given
313 fn clear_bits(flags: &mut Vec<u8>) {
314 if flags.len() > Self::BYTE_OFFSET {
315 flags[Self::BYTE_OFFSET] &= !Self::REQUIRED_MASK;
316 flags[Self::BYTE_OFFSET] &= !Self::OPTIONAL_MASK;
319 let last_non_zero_byte = flags.iter().rposition(|&byte| byte != 0);
320 let size = if let Some(offset) = last_non_zero_byte { offset + 1 } else { 0 };
321 flags.resize(size, 0u8);
325 impl <T: $feature> Features<T> {
326 /// Set this feature as optional.
327 pub fn $optional_setter(&mut self) {
328 <T as $feature>::set_optional_bit(&mut self.flags);
331 /// Set this feature as required.
332 pub fn $required_setter(&mut self) {
333 <T as $feature>::set_required_bit(&mut self.flags);
336 /// Checks if this feature is supported.
337 pub fn $supported_getter(&self) -> bool {
338 <T as $feature>::supports_feature(&self.flags)
343 impl $feature for $context {
345 const ASSERT_EVEN_BIT_PARITY: usize = 0 - (<Self as $feature>::EVEN_BIT % 2);
348 const ASSERT_ODD_BIT_PARITY: usize = (<Self as $feature>::ODD_BIT % 2) - 1;
350 // (byte & (REQUIRED_MASK | OPTIONAL_MASK)) >> (EVEN_BIT % 8) == 3
351 #[cfg(not(test))] // We violate this constraint with `UnknownFeature`
352 const ASSERT_BITS_IN_MASK: u8 =
353 ((<$context>::KNOWN_FEATURE_MASK[<Self as $feature>::BYTE_OFFSET] & (<Self as $feature>::REQUIRED_MASK | <Self as $feature>::OPTIONAL_MASK))
354 >> (<Self as $feature>::EVEN_BIT % 8)) - 3;
358 ($odd_bit: expr, $feature: ident, [$($context: ty),+], $doc: expr, $optional_setter: ident,
359 $required_setter: ident, $supported_getter: ident, $required_getter: ident) => {
360 define_feature!($odd_bit, $feature, [$($context),+], $doc, $optional_setter, $required_setter, $supported_getter);
361 impl <T: $feature> Features<T> {
362 /// Checks if this feature is required.
363 pub fn $required_getter(&self) -> bool {
364 <T as $feature>::requires_feature(&self.flags)
370 define_feature!(1, DataLossProtect, [InitContext, NodeContext],
371 "Feature flags for `option_data_loss_protect`.", set_data_loss_protect_optional,
372 set_data_loss_protect_required, supports_data_loss_protect, requires_data_loss_protect);
373 // NOTE: Per Bolt #9, initial_routing_sync has no even bit.
374 define_feature!(3, InitialRoutingSync, [InitContext], "Feature flags for `initial_routing_sync`.",
375 set_initial_routing_sync_optional, set_initial_routing_sync_required,
376 initial_routing_sync);
377 define_feature!(5, UpfrontShutdownScript, [InitContext, NodeContext],
378 "Feature flags for `option_upfront_shutdown_script`.", set_upfront_shutdown_script_optional,
379 set_upfront_shutdown_script_required, supports_upfront_shutdown_script,
380 requires_upfront_shutdown_script);
381 define_feature!(7, GossipQueries, [InitContext, NodeContext],
382 "Feature flags for `gossip_queries`.", set_gossip_queries_optional, set_gossip_queries_required,
383 supports_gossip_queries, requires_gossip_queries);
384 define_feature!(9, VariableLengthOnion, [InitContext, NodeContext, Bolt11InvoiceContext],
385 "Feature flags for `var_onion_optin`.", set_variable_length_onion_optional,
386 set_variable_length_onion_required, supports_variable_length_onion,
387 requires_variable_length_onion);
388 define_feature!(13, StaticRemoteKey, [InitContext, NodeContext, ChannelTypeContext],
389 "Feature flags for `option_static_remotekey`.", set_static_remote_key_optional,
390 set_static_remote_key_required, supports_static_remote_key, requires_static_remote_key);
391 define_feature!(15, PaymentSecret, [InitContext, NodeContext, Bolt11InvoiceContext],
392 "Feature flags for `payment_secret`.", set_payment_secret_optional, set_payment_secret_required,
393 supports_payment_secret, requires_payment_secret);
394 define_feature!(17, BasicMPP, [InitContext, NodeContext, Bolt11InvoiceContext, Bolt12InvoiceContext],
395 "Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
396 supports_basic_mpp, requires_basic_mpp);
397 define_feature!(19, Wumbo, [InitContext, NodeContext],
398 "Feature flags for `option_support_large_channel` (aka wumbo channels).", set_wumbo_optional, set_wumbo_required,
399 supports_wumbo, requires_wumbo);
400 define_feature!(21, AnchorsNonzeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
401 "Feature flags for `option_anchors_nonzero_fee_htlc_tx`.", set_anchors_nonzero_fee_htlc_tx_optional,
402 set_anchors_nonzero_fee_htlc_tx_required, supports_anchors_nonzero_fee_htlc_tx, requires_anchors_nonzero_fee_htlc_tx);
403 define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
404 "Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
405 set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
406 define_feature!(25, RouteBlinding, [InitContext, NodeContext],
407 "Feature flags for `option_route_blinding`.", set_route_blinding_optional,
408 set_route_blinding_required, supports_route_blinding, requires_route_blinding);
409 define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
410 "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
411 set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
412 define_feature!(31, Taproot, [InitContext, NodeContext, ChannelTypeContext],
413 "Feature flags for `option_taproot`.", set_taproot_optional,
414 set_taproot_required, supports_taproot, requires_taproot);
415 define_feature!(39, OnionMessages, [InitContext, NodeContext],
416 "Feature flags for `option_onion_messages`.", set_onion_messages_optional,
417 set_onion_messages_required, supports_onion_messages, requires_onion_messages);
418 define_feature!(45, ChannelType, [InitContext, NodeContext],
419 "Feature flags for `option_channel_type`.", set_channel_type_optional,
420 set_channel_type_required, supports_channel_type, requires_channel_type);
421 define_feature!(47, SCIDPrivacy, [InitContext, NodeContext, ChannelTypeContext],
422 "Feature flags for only forwarding with SCID aliasing. Called `option_scid_alias` in the BOLTs",
423 set_scid_privacy_optional, set_scid_privacy_required, supports_scid_privacy, requires_scid_privacy);
424 define_feature!(49, PaymentMetadata, [Bolt11InvoiceContext],
425 "Feature flags for payment metadata in invoices.", set_payment_metadata_optional,
426 set_payment_metadata_required, supports_payment_metadata, requires_payment_metadata);
427 define_feature!(51, ZeroConf, [InitContext, NodeContext, ChannelTypeContext],
428 "Feature flags for accepting channels with zero confirmations. Called `option_zeroconf` in the BOLTs",
429 set_zero_conf_optional, set_zero_conf_required, supports_zero_conf, requires_zero_conf);
430 define_feature!(55, Keysend, [NodeContext],
431 "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
432 supports_keysend, requires_keysend);
433 define_feature!(57, Trampoline, [InitContext, NodeContext, Bolt11InvoiceContext],
434 "Feature flags for Trampoline routing.", set_trampoline_routing_optional, set_trampoline_routing_required,
435 supports_trampoline_routing, requires_trampoline_routing);
436 // Note: update the module-level docs when a new feature bit is added!
439 define_feature!(123456789, UnknownFeature,
440 [NodeContext, ChannelContext, Bolt11InvoiceContext, OfferContext, InvoiceRequestContext, Bolt12InvoiceContext, BlindedHopContext],
441 "Feature flags for an unknown feature used in testing.", set_unknown_feature_optional,
442 set_unknown_feature_required, supports_unknown_test_feature, requires_unknown_test_feature);
445 const ANY_REQUIRED_FEATURES_MASK: u8 = 0b01_01_01_01;
446 const ANY_OPTIONAL_FEATURES_MASK: u8 = 0b10_10_10_10;
448 /// Tracks the set of features which a node implements, templated by the context in which it
451 /// This is not exported to bindings users as we map the concrete feature types below directly instead
453 pub struct Features<T: sealed::Context> {
454 /// Note that, for convenience, flags is LITTLE endian (despite being big-endian on the wire)
456 mark: PhantomData<T>,
459 impl<T: sealed::Context, Rhs: Borrow<Self>> core::ops::BitOrAssign<Rhs> for Features<T> {
460 fn bitor_assign(&mut self, rhs: Rhs) {
461 let total_feature_len = cmp::max(self.flags.len(), rhs.borrow().flags.len());
462 self.flags.resize(total_feature_len, 0u8);
463 for (byte, rhs_byte) in self.flags.iter_mut().zip(rhs.borrow().flags.iter()) {
469 impl<T: sealed::Context> core::ops::BitOr for Features<T> {
472 fn bitor(mut self, o: Self) -> Self {
478 impl<T: sealed::Context> Clone for Features<T> {
479 fn clone(&self) -> Self {
481 flags: self.flags.clone(),
486 impl<T: sealed::Context> Hash for Features<T> {
487 fn hash<H: Hasher>(&self, hasher: &mut H) {
488 let mut nonzero_flags = &self.flags[..];
489 while nonzero_flags.last() == Some(&0) {
490 nonzero_flags = &nonzero_flags[..nonzero_flags.len() - 1];
492 nonzero_flags.hash(hasher);
495 impl<T: sealed::Context> PartialEq for Features<T> {
496 fn eq(&self, o: &Self) -> bool {
497 let mut o_iter = o.flags.iter();
498 let mut self_iter = self.flags.iter();
500 match (o_iter.next(), self_iter.next()) {
501 (Some(o), Some(us)) => if o != us { return false },
502 (Some(b), None) | (None, Some(b)) => if *b != 0 { return false },
503 (None, None) => return true,
508 impl<T: sealed::Context> PartialOrd for Features<T> {
509 fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
510 self.flags.partial_cmp(&other.flags)
513 impl<T: sealed::Context + Eq> Ord for Features<T> {
514 fn cmp(&self, other: &Self) -> cmp::Ordering {
515 self.flags.cmp(&other.flags)
518 impl<T: sealed::Context> fmt::Debug for Features<T> {
519 fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
524 /// Features used within an `init` message.
525 pub type InitFeatures = Features<sealed::InitContext>;
526 /// Features used within a `node_announcement` message.
527 pub type NodeFeatures = Features<sealed::NodeContext>;
528 /// Features used within a `channel_announcement` message.
529 pub type ChannelFeatures = Features<sealed::ChannelContext>;
530 /// Features used within an invoice.
531 pub type Bolt11InvoiceFeatures = Features<sealed::Bolt11InvoiceContext>;
532 /// Features used within an `offer`.
533 pub type OfferFeatures = Features<sealed::OfferContext>;
534 /// Features used within an `invoice_request`.
535 pub type InvoiceRequestFeatures = Features<sealed::InvoiceRequestContext>;
536 /// Features used within an `invoice`.
537 pub type Bolt12InvoiceFeatures = Features<sealed::Bolt12InvoiceContext>;
538 /// Features used within BOLT 4 encrypted_data_tlv and BOLT 12 blinded_payinfo
539 pub type BlindedHopFeatures = Features<sealed::BlindedHopContext>;
541 /// Features used within the channel_type field in an OpenChannel message.
543 /// A channel is always of some known "type", describing the transaction formats used and the exact
544 /// semantics of our interaction with our peer.
546 /// Note that because a channel is a specific type which is proposed by the opener and accepted by
547 /// the counterparty, only required features are allowed here.
549 /// This is serialized differently from other feature types - it is not prefixed by a length, and
550 /// thus must only appear inside a TLV where its length is known in advance.
551 pub type ChannelTypeFeatures = Features<sealed::ChannelTypeContext>;
554 /// Writes all features present up to, and including, 13.
555 pub(crate) fn write_up_to_13<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
556 let len = cmp::min(2, self.flags.len());
557 (len as u16).write(w)?;
558 for i in (0..len).rev() {
560 self.flags[i].write(w)?;
562 // On byte 1, we want up-to-and-including-bit-13, 0-indexed, which is
563 // up-to-and-including-bit-5, 0-indexed, on this byte:
564 (self.flags[i] & 0b00_11_11_11).write(w)?;
570 /// Converts `InitFeatures` to `Features<C>`. Only known `InitFeatures` relevant to context `C`
571 /// are included in the result.
572 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
573 self.to_context_internal()
577 impl Bolt11InvoiceFeatures {
578 /// Converts `Bolt11InvoiceFeatures` to `Features<C>`. Only known `Bolt11InvoiceFeatures` relevant to
579 /// context `C` are included in the result.
580 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
581 self.to_context_internal()
584 /// Getting a route for a keysend payment to a private node requires providing the payee's
585 /// features (since they were not announced in a node announcement). However, keysend payments
586 /// don't have an invoice to pull the payee's features from, so this method is provided for use in
587 /// [`PaymentParameters::for_keysend`], thus omitting the need for payers to manually construct an
588 /// `Bolt11InvoiceFeatures` for [`find_route`].
590 /// MPP keysend is not widely supported yet, so we parameterize support to allow the user to
591 /// choose whether their router should find multi-part routes.
593 /// [`PaymentParameters::for_keysend`]: crate::routing::router::PaymentParameters::for_keysend
594 /// [`find_route`]: crate::routing::router::find_route
595 pub(crate) fn for_keysend(allow_mpp: bool) -> Bolt11InvoiceFeatures {
596 let mut res = Bolt11InvoiceFeatures::empty();
597 res.set_variable_length_onion_optional();
599 res.set_basic_mpp_optional();
605 impl Bolt12InvoiceFeatures {
606 /// Converts [`Bolt12InvoiceFeatures`] to [`Features<C>`]. Only known [`Bolt12InvoiceFeatures`]
607 /// relevant to context `C` are included in the result.
608 pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
609 self.to_context_internal()
613 impl ChannelTypeFeatures {
614 // Maps the relevant `InitFeatures` to `ChannelTypeFeatures`. Any unknown features to
615 // `ChannelTypeFeatures` are not included in the result.
616 pub(crate) fn from_init(init: &InitFeatures) -> Self {
617 let mut ret = init.to_context_internal();
618 // ChannelTypeFeatures must only contain required bits, so we OR the required forms of all
619 // optional bits and then AND out the optional ones.
620 for byte in ret.flags.iter_mut() {
621 *byte |= (*byte & ANY_OPTIONAL_FEATURES_MASK) >> 1;
622 *byte &= ANY_REQUIRED_FEATURES_MASK;
627 /// Constructs a ChannelTypeFeatures with only static_remotekey set
628 pub(crate) fn only_static_remote_key() -> Self {
629 let mut ret = Self::empty();
630 <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
634 /// Constructs a ChannelTypeFeatures with anchors support
635 pub(crate) fn anchors_zero_htlc_fee_and_dependencies() -> Self {
636 let mut ret = Self::empty();
637 <sealed::ChannelTypeContext as sealed::StaticRemoteKey>::set_required_bit(&mut ret.flags);
638 <sealed::ChannelTypeContext as sealed::AnchorsZeroFeeHtlcTx>::set_required_bit(&mut ret.flags);
643 impl ToBase32 for Bolt11InvoiceFeatures {
644 fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
645 // Explanation for the "4": the normal way to round up when dividing is to add the divisor
646 // minus one before dividing
647 let length_u5s = (self.flags.len() * 8 + 4) / 5 as usize;
648 let mut res_u5s: Vec<u5> = vec![u5::try_from_u8(0).unwrap(); length_u5s];
649 for (byte_idx, byte) in self.flags.iter().enumerate() {
650 let bit_pos_from_left_0_indexed = byte_idx * 8;
651 let new_u5_idx = length_u5s - (bit_pos_from_left_0_indexed / 5) as usize - 1;
652 let new_bit_pos = bit_pos_from_left_0_indexed % 5;
653 let shifted_chunk_u16 = (*byte as u16) << new_bit_pos;
654 let curr_u5_as_u8 = res_u5s[new_u5_idx].to_u8();
655 res_u5s[new_u5_idx] = u5::try_from_u8(curr_u5_as_u8 | ((shifted_chunk_u16 & 0x001f) as u8)).unwrap();
657 let curr_u5_as_u8 = res_u5s[new_u5_idx - 1].to_u8();
658 res_u5s[new_u5_idx - 1] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 5) & 0x001f) as u8)).unwrap();
661 let curr_u5_as_u8 = res_u5s[new_u5_idx - 2].to_u8();
662 res_u5s[new_u5_idx - 2] = u5::try_from_u8(curr_u5_as_u8 | (((shifted_chunk_u16 >> 10) & 0x001f) as u8)).unwrap();
665 // Trim the highest feature bits.
666 while !res_u5s.is_empty() && res_u5s[0] == u5::try_from_u8(0).unwrap() {
669 writer.write(&res_u5s)
673 impl Base32Len for Bolt11InvoiceFeatures {
674 fn base32_len(&self) -> usize {
675 self.to_base32().len()
679 impl FromBase32 for Bolt11InvoiceFeatures {
680 type Err = bech32::Error;
682 fn from_base32(field_data: &[u5]) -> Result<Bolt11InvoiceFeatures, bech32::Error> {
683 // Explanation for the "7": the normal way to round up when dividing is to add the divisor
684 // minus one before dividing
685 let length_bytes = (field_data.len() * 5 + 7) / 8 as usize;
686 let mut res_bytes: Vec<u8> = vec![0; length_bytes];
687 for (u5_idx, chunk) in field_data.iter().enumerate() {
688 let bit_pos_from_right_0_indexed = (field_data.len() - u5_idx - 1) * 5;
689 let new_byte_idx = (bit_pos_from_right_0_indexed / 8) as usize;
690 let new_bit_pos = bit_pos_from_right_0_indexed % 8;
691 let chunk_u16 = chunk.to_u8() as u16;
692 res_bytes[new_byte_idx] |= ((chunk_u16 << new_bit_pos) & 0xff) as u8;
693 if new_byte_idx != length_bytes - 1 {
694 res_bytes[new_byte_idx + 1] |= ((chunk_u16 >> (8-new_bit_pos)) & 0xff) as u8;
697 // Trim the highest feature bits.
698 while !res_bytes.is_empty() && res_bytes[res_bytes.len() - 1] == 0 {
701 Ok(Bolt11InvoiceFeatures::from_le_bytes(res_bytes))
705 impl<T: sealed::Context> Features<T> {
706 /// Create a blank Features with no features set
707 pub fn empty() -> Self {
714 /// Converts `Features<T>` to `Features<C>`. Only known `T` features relevant to context `C` are
715 /// included in the result.
716 fn to_context_internal<C: sealed::Context>(&self) -> Features<C> {
717 let from_byte_count = T::KNOWN_FEATURE_MASK.len();
718 let to_byte_count = C::KNOWN_FEATURE_MASK.len();
719 let mut flags = Vec::new();
720 for (i, byte) in self.flags.iter().enumerate() {
721 if i < from_byte_count && i < to_byte_count {
722 let from_known_features = T::KNOWN_FEATURE_MASK[i];
723 let to_known_features = C::KNOWN_FEATURE_MASK[i];
724 flags.push(byte & from_known_features & to_known_features);
727 Features::<C> { flags, mark: PhantomData, }
730 /// Create a Features given a set of flags, in little-endian. This is in reverse byte order from
731 /// most on-the-wire encodings.
733 /// This is not exported to bindings users as we don't support export across multiple T
734 pub fn from_le_bytes(flags: Vec<u8>) -> Features<T> {
742 /// Gets the underlying flags set, in LE.
743 pub fn le_flags(&self) -> &Vec<u8> {
747 fn write_be<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
748 for f in self.flags.iter().rev() { // Swap back to big-endian
754 /// Create a [`Features`] given a set of flags, in big-endian. This is in byte order from
755 /// most on-the-wire encodings.
757 /// This is not exported to bindings users as we don't support export across multiple T
758 pub fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
759 flags.reverse(); // Swap to little-endian
766 pub(crate) fn supports_any_optional_bits(&self) -> bool {
767 self.flags.iter().any(|&byte| (byte & ANY_OPTIONAL_FEATURES_MASK) != 0)
770 /// Returns true if this `Features` object contains required features unknown by `other`.
771 pub fn requires_unknown_bits_from(&self, other: &Self) -> bool {
772 // Bitwise AND-ing with all even bits set except for known features will select required
774 self.flags.iter().enumerate().any(|(i, &byte)| {
775 let unknown_features = unset_features_mask_at_position(other, i);
776 (byte & (ANY_REQUIRED_FEATURES_MASK & unknown_features)) != 0
780 pub(crate) fn required_unknown_bits_from(&self, other: &Self) -> Vec<usize> {
781 let mut unknown_bits = Vec::new();
783 // Bitwise AND-ing with all even bits set except for known features will select required
785 self.flags.iter().enumerate().for_each(|(i, &byte)| {
786 let unknown_features = unset_features_mask_at_position(other, i);
787 if byte & unknown_features != 0 {
788 for bit in (0..8).step_by(2) {
789 if ((byte & unknown_features) >> bit) & 1 == 1 {
790 unknown_bits.push(i * 8 + bit);
799 /// Returns true if this `Features` object contains unknown feature flags which are set as
801 pub fn requires_unknown_bits(&self) -> bool {
802 // Bitwise AND-ing with all even bits set except for known features will select required
804 let byte_count = T::KNOWN_FEATURE_MASK.len();
805 self.flags.iter().enumerate().any(|(i, &byte)| {
806 let unknown_features = if i < byte_count {
807 !T::KNOWN_FEATURE_MASK[i]
811 (byte & (ANY_REQUIRED_FEATURES_MASK & unknown_features)) != 0
815 pub(crate) fn supports_unknown_bits(&self) -> bool {
816 // Bitwise AND-ing with all even and odd bits set except for known features will select
817 // both required and optional unknown features.
818 let byte_count = T::KNOWN_FEATURE_MASK.len();
819 self.flags.iter().enumerate().any(|(i, &byte)| {
820 let unknown_features = if i < byte_count {
821 !T::KNOWN_FEATURE_MASK[i]
825 (byte & unknown_features) != 0
829 // Returns true if the features within `self` are a subset of the features within `other`.
830 pub(crate) fn is_subset(&self, other: &Self) -> bool {
831 for (idx, byte) in self.flags.iter().enumerate() {
832 if let Some(other_byte) = other.flags.get(idx) {
833 if byte & other_byte != *byte {
834 // `self` has bits set that `other` doesn't.
839 // `self` has a non-zero byte that `other` doesn't.
847 /// Sets a required feature bit. Errors if `bit` is outside the feature range as defined
850 /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
851 /// be set instead (i.e., `bit - 1`).
853 /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
854 pub fn set_required_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
855 self.set_feature_bit(bit - (bit % 2))
858 /// Sets an optional feature bit. Errors if `bit` is outside the feature range as defined
861 /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
862 /// set instead (i.e., `bit + 1`).
864 /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
865 pub fn set_optional_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
866 self.set_feature_bit(bit + (1 - (bit % 2)))
869 fn set_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
873 self.set_bit(bit, false)
876 /// Sets a required 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: Required bits are even. If an odd bit is given, then the corresponding even bit will
880 /// be 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_required_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
884 self.set_custom_bit(bit - (bit % 2))
887 /// Sets an optional custom feature bit. Errors if `bit` is outside the custom range as defined
888 /// by [bLIP 2] or if it is a known `T` feature.
890 /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
891 /// set instead (i.e., `bit + 1`).
893 /// [bLIP 2]: https://github.com/lightning/blips/blob/master/blip-0002.md#feature-bits
894 pub fn set_optional_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
895 self.set_custom_bit(bit + (1 - (bit % 2)))
898 fn set_custom_bit(&mut self, bit: usize) -> Result<(), ()> {
902 self.set_bit(bit, true)
905 fn set_bit(&mut self, bit: usize, custom: bool) -> Result<(), ()> {
906 let byte_offset = bit / 8;
907 let mask = 1 << (bit - 8 * byte_offset);
908 if byte_offset < T::KNOWN_FEATURE_MASK.len() && custom {
909 if (T::KNOWN_FEATURE_MASK[byte_offset] & mask) != 0 {
914 if self.flags.len() <= byte_offset {
915 self.flags.resize(byte_offset + 1, 0u8);
918 self.flags[byte_offset] |= mask;
924 impl<T: sealed::UpfrontShutdownScript> Features<T> {
926 pub(crate) fn clear_upfront_shutdown_script(mut self) -> Self {
927 <T as sealed::UpfrontShutdownScript>::clear_bits(&mut self.flags);
932 impl<T: sealed::ShutdownAnySegwit> Features<T> {
934 pub(crate) fn clear_shutdown_anysegwit(mut self) -> Self {
935 <T as sealed::ShutdownAnySegwit>::clear_bits(&mut self.flags);
940 impl<T: sealed::Wumbo> Features<T> {
942 pub(crate) fn clear_wumbo(mut self) -> Self {
943 <T as sealed::Wumbo>::clear_bits(&mut self.flags);
948 impl<T: sealed::SCIDPrivacy> Features<T> {
949 pub(crate) fn clear_scid_privacy(&mut self) {
950 <T as sealed::SCIDPrivacy>::clear_bits(&mut self.flags);
954 impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
955 pub(crate) fn clear_anchors_zero_fee_htlc_tx(&mut self) {
956 <T as sealed::AnchorsZeroFeeHtlcTx>::clear_bits(&mut self.flags);
960 impl<T: sealed::RouteBlinding> Features<T> {
962 pub(crate) fn clear_route_blinding(&mut self) {
963 <T as sealed::RouteBlinding>::clear_bits(&mut self.flags);
968 impl<T: sealed::UnknownFeature> Features<T> {
969 pub(crate) fn unknown() -> Self {
970 let mut features = Self::empty();
971 features.set_unknown_feature_required();
976 macro_rules! impl_feature_len_prefixed_write {
977 ($features: ident) => {
978 impl Writeable for $features {
979 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
980 (self.flags.len() as u16).write(w)?;
984 impl Readable for $features {
985 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
986 Ok(Self::from_be_bytes(Vec::<u8>::read(r)?))
991 impl_feature_len_prefixed_write!(InitFeatures);
992 impl_feature_len_prefixed_write!(ChannelFeatures);
993 impl_feature_len_prefixed_write!(NodeFeatures);
994 impl_feature_len_prefixed_write!(Bolt11InvoiceFeatures);
995 impl_feature_len_prefixed_write!(Bolt12InvoiceFeatures);
996 impl_feature_len_prefixed_write!(BlindedHopFeatures);
998 // Some features only appear inside of TLVs, so they don't have a length prefix when serialized.
999 macro_rules! impl_feature_tlv_write {
1000 ($features: ident) => {
1001 impl Writeable for $features {
1002 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1003 WithoutLength(self).write(w)
1006 impl Readable for $features {
1007 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
1008 Ok(WithoutLength::<Self>::read(r)?.0)
1014 impl_feature_tlv_write!(ChannelTypeFeatures);
1016 // Some features may appear both in a TLV record and as part of a TLV subtype sequence. The latter
1017 // requires a length but the former does not.
1019 impl<T: sealed::Context> Writeable for WithoutLength<&Features<T>> {
1020 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1025 impl<T: sealed::Context> Readable for WithoutLength<Features<T>> {
1026 fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
1027 let v = io_extras::read_to_end(r)?;
1028 Ok(WithoutLength(Features::<T>::from_be_bytes(v)))
1032 pub(crate) fn unset_features_mask_at_position<T: sealed::Context>(other: &Features<T>, index: usize) -> u8 {
1033 if index < other.flags.len() {
1034 // Form a mask similar to !T::KNOWN_FEATURE_MASK only for `other`
1035 !(other.flags[index]
1036 | ((other.flags[index] >> 1) & ANY_REQUIRED_FEATURES_MASK)
1037 | ((other.flags[index] << 1) & ANY_OPTIONAL_FEATURES_MASK))
1045 use super::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, Bolt11InvoiceFeatures, NodeFeatures, OfferFeatures, sealed};
1046 use bech32::{Base32Len, FromBase32, ToBase32, u5};
1047 use crate::util::ser::{Readable, WithoutLength, Writeable};
1050 fn sanity_test_unknown_bits() {
1051 let features = ChannelFeatures::empty();
1052 assert!(!features.requires_unknown_bits());
1053 assert!(!features.supports_unknown_bits());
1055 let mut features = ChannelFeatures::empty();
1056 features.set_unknown_feature_required();
1057 assert!(features.requires_unknown_bits());
1058 assert!(features.supports_unknown_bits());
1059 assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456788]);
1061 let mut features = ChannelFeatures::empty();
1062 features.set_unknown_feature_optional();
1063 assert!(!features.requires_unknown_bits());
1064 assert!(features.supports_unknown_bits());
1065 assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![]);
1067 let mut features = ChannelFeatures::empty();
1068 features.set_unknown_feature_required();
1069 features.set_custom_bit(123456786).unwrap();
1070 assert!(features.requires_unknown_bits());
1071 assert!(features.supports_unknown_bits());
1072 assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456786, 123456788]);
1074 let mut limiter = ChannelFeatures::empty();
1075 limiter.set_unknown_feature_optional();
1076 assert_eq!(features.required_unknown_bits_from(&limiter), vec![123456786]);
1080 fn requires_unknown_bits_from() {
1081 let mut features1 = InitFeatures::empty();
1082 let mut features2 = InitFeatures::empty();
1083 assert!(!features1.requires_unknown_bits_from(&features2));
1084 assert!(!features2.requires_unknown_bits_from(&features1));
1086 features1.set_data_loss_protect_required();
1087 assert!(features1.requires_unknown_bits_from(&features2));
1088 assert!(!features2.requires_unknown_bits_from(&features1));
1090 features2.set_data_loss_protect_optional();
1091 assert!(!features1.requires_unknown_bits_from(&features2));
1092 assert!(!features2.requires_unknown_bits_from(&features1));
1094 features2.set_gossip_queries_required();
1095 assert!(!features1.requires_unknown_bits_from(&features2));
1096 assert!(features2.requires_unknown_bits_from(&features1));
1098 features1.set_gossip_queries_optional();
1099 assert!(!features1.requires_unknown_bits_from(&features2));
1100 assert!(!features2.requires_unknown_bits_from(&features1));
1102 features1.set_variable_length_onion_required();
1103 assert!(features1.requires_unknown_bits_from(&features2));
1104 assert!(!features2.requires_unknown_bits_from(&features1));
1106 features2.set_variable_length_onion_optional();
1107 assert!(!features1.requires_unknown_bits_from(&features2));
1108 assert!(!features2.requires_unknown_bits_from(&features1));
1110 features1.set_basic_mpp_required();
1111 features2.set_wumbo_required();
1112 assert!(features1.requires_unknown_bits_from(&features2));
1113 assert!(features2.requires_unknown_bits_from(&features1));
1117 fn convert_to_context_with_relevant_flags() {
1118 let mut init_features = InitFeatures::empty();
1119 // Set a bunch of features we use, plus initial_routing_sync_required (which shouldn't get
1120 // converted as it's only relevant in an init context).
1121 init_features.set_initial_routing_sync_required();
1122 init_features.set_data_loss_protect_required();
1123 init_features.set_variable_length_onion_required();
1124 init_features.set_static_remote_key_required();
1125 init_features.set_payment_secret_required();
1126 init_features.set_basic_mpp_optional();
1127 init_features.set_wumbo_optional();
1128 init_features.set_anchors_zero_fee_htlc_tx_optional();
1129 init_features.set_route_blinding_optional();
1130 init_features.set_shutdown_any_segwit_optional();
1131 init_features.set_onion_messages_optional();
1132 init_features.set_channel_type_optional();
1133 init_features.set_scid_privacy_optional();
1134 init_features.set_zero_conf_optional();
1136 assert!(init_features.initial_routing_sync());
1137 assert!(!init_features.supports_upfront_shutdown_script());
1138 assert!(!init_features.supports_gossip_queries());
1140 let node_features: NodeFeatures = init_features.to_context();
1142 // Check that the flags are as expected:
1143 // - option_data_loss_protect (req)
1144 // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
1145 // - basic_mpp | wumbo | option_anchors_zero_fee_htlc_tx
1146 // - option_route_blinding | opt_shutdown_anysegwit
1148 // - option_channel_type | option_scid_alias
1149 // - option_zeroconf
1150 assert_eq!(node_features.flags.len(), 7);
1151 assert_eq!(node_features.flags[0], 0b00000001);
1152 assert_eq!(node_features.flags[1], 0b01010001);
1153 assert_eq!(node_features.flags[2], 0b10001010);
1154 assert_eq!(node_features.flags[3], 0b00001010);
1155 assert_eq!(node_features.flags[4], 0b10000000);
1156 assert_eq!(node_features.flags[5], 0b10100000);
1157 assert_eq!(node_features.flags[6], 0b00001000);
1160 // Check that cleared flags are kept blank when converting back:
1161 // - initial_routing_sync was not applicable to NodeContext
1162 // - upfront_shutdown_script was cleared before converting
1163 // - gossip_queries was cleared before converting
1164 let features: InitFeatures = node_features.to_context_internal();
1165 assert!(!features.initial_routing_sync());
1166 assert!(!features.supports_upfront_shutdown_script());
1167 assert!(!init_features.supports_gossip_queries());
1171 fn convert_to_context_with_unknown_flags() {
1172 // Ensure the `from` context has fewer known feature bytes than the `to` context.
1173 assert!(<sealed::ChannelContext as sealed::Context>::KNOWN_FEATURE_MASK.len() <
1174 <sealed::Bolt11InvoiceContext as sealed::Context>::KNOWN_FEATURE_MASK.len());
1175 let mut channel_features = ChannelFeatures::empty();
1176 channel_features.set_unknown_feature_optional();
1177 assert!(channel_features.supports_unknown_bits());
1178 let invoice_features: Bolt11InvoiceFeatures = channel_features.to_context_internal();
1179 assert!(!invoice_features.supports_unknown_bits());
1183 fn set_feature_bits() {
1184 let mut features = Bolt11InvoiceFeatures::empty();
1185 features.set_basic_mpp_optional();
1186 features.set_payment_secret_required();
1187 assert!(features.supports_basic_mpp());
1188 assert!(!features.requires_basic_mpp());
1189 assert!(features.requires_payment_secret());
1190 assert!(features.supports_payment_secret());
1192 // Set flags manually
1193 let mut features = NodeFeatures::empty();
1194 assert!(features.set_optional_feature_bit(55).is_ok());
1195 assert!(features.supports_keysend());
1196 assert!(features.set_optional_feature_bit(255).is_ok());
1197 assert!(features.set_required_feature_bit(256).is_err());
1201 fn set_custom_bits() {
1202 let mut features = Bolt11InvoiceFeatures::empty();
1203 features.set_variable_length_onion_optional();
1204 assert_eq!(features.flags[1], 0b00000010);
1206 assert!(features.set_optional_custom_bit(255).is_err());
1207 assert!(features.set_required_custom_bit(256).is_ok());
1208 assert!(features.set_required_custom_bit(258).is_ok());
1209 assert_eq!(features.flags[31], 0b00000000);
1210 assert_eq!(features.flags[32], 0b00000101);
1212 let known_bit = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::EVEN_BIT;
1213 let byte_offset = <sealed::Bolt11InvoiceContext as sealed::PaymentSecret>::BYTE_OFFSET;
1214 assert_eq!(byte_offset, 1);
1215 assert_eq!(features.flags[byte_offset], 0b00000010);
1216 assert!(features.set_required_custom_bit(known_bit).is_err());
1217 assert_eq!(features.flags[byte_offset], 0b00000010);
1219 let mut features = Bolt11InvoiceFeatures::empty();
1220 assert!(features.set_optional_custom_bit(256).is_ok());
1221 assert!(features.set_optional_custom_bit(259).is_ok());
1222 assert_eq!(features.flags[32], 0b00001010);
1224 let mut features = Bolt11InvoiceFeatures::empty();
1225 assert!(features.set_required_custom_bit(257).is_ok());
1226 assert!(features.set_required_custom_bit(258).is_ok());
1227 assert_eq!(features.flags[32], 0b00000101);
1231 fn encodes_features_without_length() {
1232 let features = OfferFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
1233 assert_eq!(features.flags.len(), 8);
1235 let mut serialized_features = Vec::new();
1236 WithoutLength(&features).write(&mut serialized_features).unwrap();
1237 assert_eq!(serialized_features.len(), 8);
1239 let deserialized_features =
1240 WithoutLength::<OfferFeatures>::read(&mut &serialized_features[..]).unwrap().0;
1241 assert_eq!(features, deserialized_features);
1245 fn invoice_features_encoding() {
1246 let features_as_u5s = vec![
1247 u5::try_from_u8(6).unwrap(),
1248 u5::try_from_u8(10).unwrap(),
1249 u5::try_from_u8(25).unwrap(),
1250 u5::try_from_u8(1).unwrap(),
1251 u5::try_from_u8(10).unwrap(),
1252 u5::try_from_u8(0).unwrap(),
1253 u5::try_from_u8(20).unwrap(),
1254 u5::try_from_u8(2).unwrap(),
1255 u5::try_from_u8(0).unwrap(),
1256 u5::try_from_u8(6).unwrap(),
1257 u5::try_from_u8(0).unwrap(),
1258 u5::try_from_u8(16).unwrap(),
1259 u5::try_from_u8(1).unwrap(),
1261 let features = Bolt11InvoiceFeatures::from_le_bytes(vec![1, 2, 3, 4, 5, 42, 100, 101]);
1263 // Test length calculation.
1264 assert_eq!(features.base32_len(), 13);
1266 // Test serialization.
1267 let features_serialized = features.to_base32();
1268 assert_eq!(features_as_u5s, features_serialized);
1270 // Test deserialization.
1271 let features_deserialized = Bolt11InvoiceFeatures::from_base32(&features_as_u5s).unwrap();
1272 assert_eq!(features, features_deserialized);
1276 fn test_channel_type_mapping() {
1277 // If we map an Bolt11InvoiceFeatures with StaticRemoteKey optional, it should map into a
1278 // required-StaticRemoteKey ChannelTypeFeatures.
1279 let mut init_features = InitFeatures::empty();
1280 init_features.set_static_remote_key_optional();
1281 let converted_features = ChannelTypeFeatures::from_init(&init_features);
1282 assert_eq!(converted_features, ChannelTypeFeatures::only_static_remote_key());
1283 assert!(!converted_features.supports_any_optional_bits());
1284 assert!(converted_features.requires_static_remote_key());
1288 #[cfg(feature = "std")]
1289 fn test_excess_zero_bytes_ignored() {
1290 // Checks that `Hash` and `PartialEq` ignore excess zero bytes, which may appear due to
1291 // feature conversion or because a peer serialized their feature poorly.
1292 use std::collections::hash_map::DefaultHasher;
1293 use std::hash::{Hash, Hasher};
1295 let mut zerod_features = InitFeatures::empty();
1296 zerod_features.flags = vec![0];
1297 let empty_features = InitFeatures::empty();
1298 assert!(empty_features.flags.is_empty());
1300 assert_eq!(zerod_features, empty_features);
1302 let mut zerod_hash = DefaultHasher::new();
1303 zerod_features.hash(&mut zerod_hash);
1304 let mut empty_hash = DefaultHasher::new();
1305 empty_features.hash(&mut empty_hash);
1306 assert_eq!(zerod_hash.finish(), empty_hash.finish());