_ Git - rust-lightning/blob - lightning-invoice/src/utils.rs

   1 //! Convenient utilities to create an invoice.
   2
   3 use crate::{Bolt11Invoice, CreationError, Currency, InvoiceBuilder, SignOrCreationError};
   4
   5 use crate::{prelude::*, Description, Bolt11InvoiceDescription, Sha256};
   6 use bech32::ToBase32;
   7 use bitcoin::hashes::Hash;
   8 use lightning::chain;
   9 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
  10 use lightning::sign::{Recipient, NodeSigner, SignerProvider, EntropySource};
  11 use lightning::ln::types::{PaymentHash, PaymentSecret};
  12 use lightning::ln::channel_state::ChannelDetails;
  13 use lightning::ln::channelmanager::{ChannelManager, MIN_FINAL_CLTV_EXPIRY_DELTA};
  14 use lightning::ln::channelmanager::{PhantomRouteHints, MIN_CLTV_EXPIRY_DELTA};
  15 use lightning::ln::inbound_payment::{create, create_from_hash, ExpandedKey};
  16 use lightning::routing::gossip::RoutingFees;
  17 use lightning::routing::router::{RouteHint, RouteHintHop, Router};
  18 use lightning::util::logger::{Logger, Record};
  19 use secp256k1::PublicKey;
  20 use alloc::collections::{btree_map, BTreeMap};
  21 use core::ops::Deref;
  22 use core::time::Duration;
  23 #[cfg(not(feature = "std"))]
  24 use core::iter::Iterator;
  25
  26 /// Utility to create an invoice that can be paid to one of multiple nodes, or a "phantom invoice."
  27 /// See [`PhantomKeysManager`] for more information on phantom node payments.
  28 ///
  29 /// `phantom_route_hints` parameter:
  30 /// * Contains channel info for all nodes participating in the phantom invoice
  31 /// * Entries are retrieved from a call to [`ChannelManager::get_phantom_route_hints`] on each
  32 ///   participating node
  33 /// * It is fine to cache `phantom_route_hints` and reuse it across invoices, as long as the data is
  34 ///   updated when a channel becomes disabled or closes
  35 /// * Note that if too many channels are included in [`PhantomRouteHints::channels`], the invoice
  36 ///   may be too long for QR code scanning. To fix this, `PhantomRouteHints::channels` may be pared
  37 ///   down
  38 ///
  39 /// `payment_hash` can be specified if you have a specific need for a custom payment hash (see the difference
  40 /// between [`ChannelManager::create_inbound_payment`] and [`ChannelManager::create_inbound_payment_for_hash`]).
  41 /// If `None` is provided for `payment_hash`, then one will be created.
  42 ///
  43 /// `invoice_expiry_delta_secs` describes the number of seconds that the invoice is valid for
  44 /// in excess of the current time.
  45 ///
  46 /// `duration_since_epoch` is the current time since epoch in seconds.
  47 ///
  48 /// You can specify a custom `min_final_cltv_expiry_delta`, or let LDK default it to
  49 /// [`MIN_FINAL_CLTV_EXPIRY_DELTA`]. The provided expiry must be at least [`MIN_FINAL_CLTV_EXPIRY_DELTA`] - 3.
  50 /// Note that LDK will add a buffer of 3 blocks to the delta to allow for up to a few new block
  51 /// confirmations during routing.
  52 ///
  53 /// Note that the provided `keys_manager`'s `NodeSigner` implementation must support phantom
  54 /// invoices in its `sign_invoice` implementation ([`PhantomKeysManager`] satisfies this
  55 /// requirement).
  56 ///
  57 /// [`PhantomKeysManager`]: lightning::sign::PhantomKeysManager
  58 /// [`ChannelManager::get_phantom_route_hints`]: lightning::ln::channelmanager::ChannelManager::get_phantom_route_hints
  59 /// [`ChannelManager::create_inbound_payment`]: lightning::ln::channelmanager::ChannelManager::create_inbound_payment
  60 /// [`ChannelManager::create_inbound_payment_for_hash`]: lightning::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
  61 /// [`PhantomRouteHints::channels`]: lightning::ln::channelmanager::PhantomRouteHints::channels
  62 /// [`MIN_FINAL_CLTV_EXPIRY_DETLA`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA
  63 ///
  64 /// This can be used in a `no_std` environment, where [`std::time::SystemTime`] is not
  65 /// available and the current time is supplied by the caller.
  66 pub fn create_phantom_invoice<ES: Deref, NS: Deref, L: Deref>(
  67         amt_msat: Option<u64>, payment_hash: Option<PaymentHash>, description: String,
  68         invoice_expiry_delta_secs: u32, phantom_route_hints: Vec<PhantomRouteHints>, entropy_source: ES,
  69         node_signer: NS, logger: L, network: Currency, min_final_cltv_expiry_delta: Option<u16>, duration_since_epoch: Duration,
  70 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
  71 where
  72         ES::Target: EntropySource,
  73         NS::Target: NodeSigner,
  74         L::Target: Logger,
  75 {
  76         let description = Description::new(description).map_err(SignOrCreationError::CreationError)?;
  77         let description = Bolt11InvoiceDescription::Direct(&description,);
  78         _create_phantom_invoice::<ES, NS, L>(
  79                 amt_msat, payment_hash, description, invoice_expiry_delta_secs, phantom_route_hints,
  80                 entropy_source, node_signer, logger, network, min_final_cltv_expiry_delta, duration_since_epoch,
  81         )
  82 }
  83
  84 /// Utility to create an invoice that can be paid to one of multiple nodes, or a "phantom invoice."
  85 /// See [`PhantomKeysManager`] for more information on phantom node payments.
  86 ///
  87 /// `phantom_route_hints` parameter:
  88 /// * Contains channel info for all nodes participating in the phantom invoice
  89 /// * Entries are retrieved from a call to [`ChannelManager::get_phantom_route_hints`] on each
  90 ///   participating node
  91 /// * It is fine to cache `phantom_route_hints` and reuse it across invoices, as long as the data is
  92 ///   updated when a channel becomes disabled or closes
  93 /// * Note that the route hints generated from `phantom_route_hints` will be limited to a maximum
  94 ///   of 3 hints to ensure that the invoice can be scanned in a QR code. These hints are selected
  95 ///   in the order that the nodes in `PhantomRouteHints` are specified, selecting one hint per node
  96 ///   until the maximum is hit. Callers may provide as many `PhantomRouteHints::channels` as
  97 ///   desired, but note that some nodes will be trimmed if more than 3 nodes are provided.
  98 ///
  99 /// `description_hash` is a SHA-256 hash of the description text
 100 ///
 101 /// `payment_hash` can be specified if you have a specific need for a custom payment hash (see the difference
 102 /// between [`ChannelManager::create_inbound_payment`] and [`ChannelManager::create_inbound_payment_for_hash`]).
 103 /// If `None` is provided for `payment_hash`, then one will be created.
 104 ///
 105 /// `invoice_expiry_delta_secs` describes the number of seconds that the invoice is valid for
 106 /// in excess of the current time.
 107 ///
 108 /// `duration_since_epoch` is the current time since epoch in seconds.
 109 ///
 110 /// Note that the provided `keys_manager`'s `NodeSigner` implementation must support phantom
 111 /// invoices in its `sign_invoice` implementation ([`PhantomKeysManager`] satisfies this
 112 /// requirement).
 113 ///
 114 /// [`PhantomKeysManager`]: lightning::sign::PhantomKeysManager
 115 /// [`ChannelManager::get_phantom_route_hints`]: lightning::ln::channelmanager::ChannelManager::get_phantom_route_hints
 116 /// [`ChannelManager::create_inbound_payment`]: lightning::ln::channelmanager::ChannelManager::create_inbound_payment
 117 /// [`ChannelManager::create_inbound_payment_for_hash`]: lightning::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
 118 /// [`PhantomRouteHints::channels`]: lightning::ln::channelmanager::PhantomRouteHints::channels
 119 ///
 120 /// This can be used in a `no_std` environment, where [`std::time::SystemTime`] is not
 121 /// available and the current time is supplied by the caller.
 122 pub fn create_phantom_invoice_with_description_hash<ES: Deref, NS: Deref, L: Deref>(
 123         amt_msat: Option<u64>, payment_hash: Option<PaymentHash>, invoice_expiry_delta_secs: u32,
 124         description_hash: Sha256, phantom_route_hints: Vec<PhantomRouteHints>, entropy_source: ES,
 125         node_signer: NS, logger: L, network: Currency, min_final_cltv_expiry_delta: Option<u16>, duration_since_epoch: Duration,
 126 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 127 where
 128         ES::Target: EntropySource,
 129         NS::Target: NodeSigner,
 130         L::Target: Logger,
 131 {
 132         _create_phantom_invoice::<ES, NS, L>(
 133                 amt_msat, payment_hash, Bolt11InvoiceDescription::Hash(&description_hash),
 134                 invoice_expiry_delta_secs, phantom_route_hints, entropy_source, node_signer, logger, network,
 135                 min_final_cltv_expiry_delta, duration_since_epoch,
 136         )
 137 }
 138
 139 const MAX_CHANNEL_HINTS: usize = 3;
 140
 141 fn _create_phantom_invoice<ES: Deref, NS: Deref, L: Deref>(
 142         amt_msat: Option<u64>, payment_hash: Option<PaymentHash>, description: Bolt11InvoiceDescription,
 143         invoice_expiry_delta_secs: u32, phantom_route_hints: Vec<PhantomRouteHints>, entropy_source: ES,
 144         node_signer: NS, logger: L, network: Currency, min_final_cltv_expiry_delta: Option<u16>, duration_since_epoch: Duration,
 145 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 146 where
 147         ES::Target: EntropySource,
 148         NS::Target: NodeSigner,
 149         L::Target: Logger,
 150 {
 151
 152         if phantom_route_hints.is_empty() {
 153                 return Err(SignOrCreationError::CreationError(
 154                         CreationError::MissingRouteHints,
 155                 ));
 156         }
 157
 158         if min_final_cltv_expiry_delta.is_some() && min_final_cltv_expiry_delta.unwrap().saturating_add(3) < MIN_FINAL_CLTV_EXPIRY_DELTA {
 159                 return Err(SignOrCreationError::CreationError(CreationError::MinFinalCltvExpiryDeltaTooShort));
 160         }
 161
 162         let invoice = match description {
 163                 Bolt11InvoiceDescription::Direct(description) => {
 164                         InvoiceBuilder::new(network).description(description.0.0.clone())
 165                 }
 166                 Bolt11InvoiceDescription::Hash(hash) => InvoiceBuilder::new(network).description_hash(hash.0),
 167         };
 168
 169         // If we ever see performance here being too slow then we should probably take this ExpandedKey as a parameter instead.
 170         let keys = ExpandedKey::new(&node_signer.get_inbound_payment_key_material());
 171         let (payment_hash, payment_secret) = if let Some(payment_hash) = payment_hash {
 172                 let payment_secret = create_from_hash(
 173                         &keys,
 174                         amt_msat,
 175                         payment_hash,
 176                         invoice_expiry_delta_secs,
 177                         duration_since_epoch
 178                                 .as_secs(),
 179                         min_final_cltv_expiry_delta,
 180                 )
 181                 .map_err(|_| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 182                 (payment_hash, payment_secret)
 183         } else {
 184                 create(
 185                         &keys,
 186                         amt_msat,
 187                         invoice_expiry_delta_secs,
 188                         &entropy_source,
 189                         duration_since_epoch
 190                                 .as_secs(),
 191                         min_final_cltv_expiry_delta,
 192                 )
 193                 .map_err(|_| SignOrCreationError::CreationError(CreationError::InvalidAmount))?
 194         };
 195
 196         log_trace!(logger, "Creating phantom invoice from {} participating nodes with payment hash {}",
 197                 phantom_route_hints.len(), &payment_hash);
 198
 199         let mut invoice = invoice
 200                 .duration_since_epoch(duration_since_epoch)
 201                 .payment_hash(Hash::from_slice(&payment_hash.0).unwrap())
 202                 .payment_secret(payment_secret)
 203                 .min_final_cltv_expiry_delta(
 204                         // Add a buffer of 3 to the delta if present, otherwise use LDK's minimum.
 205                         min_final_cltv_expiry_delta.map(|x| x.saturating_add(3)).unwrap_or(MIN_FINAL_CLTV_EXPIRY_DELTA).into())
 206                 .expiry_time(Duration::from_secs(invoice_expiry_delta_secs.into()));
 207         if let Some(amt) = amt_msat {
 208                 invoice = invoice.amount_milli_satoshis(amt);
 209         }
 210
 211
 212         for route_hint in select_phantom_hints(amt_msat, phantom_route_hints, logger).take(MAX_CHANNEL_HINTS) {
 213                 invoice = invoice.private_route(route_hint);
 214         }
 215
 216         let raw_invoice = match invoice.build_raw() {
 217                 Ok(inv) => inv,
 218                 Err(e) => return Err(SignOrCreationError::CreationError(e))
 219         };
 220         let hrp_str = raw_invoice.hrp.to_string();
 221         let hrp_bytes = hrp_str.as_bytes();
 222         let data_without_signature = raw_invoice.data.to_base32();
 223         let signed_raw_invoice = raw_invoice.sign(|_| node_signer.sign_invoice(hrp_bytes, &data_without_signature, Recipient::PhantomNode));
 224         match signed_raw_invoice {
 225                 Ok(inv) => Ok(Bolt11Invoice::from_signed(inv).unwrap()),
 226                 Err(e) => Err(SignOrCreationError::SignError(e))
 227         }
 228 }
 229
 230 /// Utility to select route hints for phantom invoices.
 231 /// See [`PhantomKeysManager`] for more information on phantom node payments.
 232 ///
 233 /// To ensure that the phantom invoice is still readable by QR code, we limit to 3 hints per invoice:
 234 /// * Select up to three channels per node.
 235 /// * Select one hint from each node, up to three hints or until we run out of hints.
 236 ///
 237 /// [`PhantomKeysManager`]: lightning::sign::PhantomKeysManager
 238 fn select_phantom_hints<L: Deref>(amt_msat: Option<u64>, phantom_route_hints: Vec<PhantomRouteHints>,
 239         logger: L) -> impl Iterator<Item = RouteHint>
 240 where
 241         L::Target: Logger,
 242 {
 243         let mut phantom_hints: Vec<_> = Vec::new();
 244
 245         for PhantomRouteHints { channels, phantom_scid, real_node_pubkey } in phantom_route_hints {
 246                 log_trace!(logger, "Generating phantom route hints for node {}",
 247                         log_pubkey!(real_node_pubkey));
 248                 let route_hints = sort_and_filter_channels(channels, amt_msat, &logger);
 249
 250                 // If we have any public channel, the route hints from `sort_and_filter_channels` will be
 251                 // empty. In that case we create a RouteHint on which we will push a single hop with the
 252                 // phantom route into the invoice, and let the sender find the path to the `real_node_pubkey`
 253                 // node by looking at our public channels.
 254                 let empty_route_hints = route_hints.len() == 0;
 255                 let mut have_pushed_empty = false;
 256                 let route_hints = route_hints
 257                         .chain(core::iter::from_fn(move || {
 258                                 if empty_route_hints && !have_pushed_empty {
 259                                         // set flag of having handled the empty route_hints and ensure empty vector
 260                                         // returned only once
 261                                         have_pushed_empty = true;
 262                                         Some(RouteHint(Vec::new()))
 263                                 } else {
 264                                         None
 265                                 }
 266                         }))
 267                         .map(move |mut hint| {
 268                                 hint.0.push(RouteHintHop {
 269                                         src_node_id: real_node_pubkey,
 270                                         short_channel_id: phantom_scid,
 271                                         fees: RoutingFees {
 272                                                 base_msat: 0,
 273                                                 proportional_millionths: 0,
 274                                         },
 275                                         cltv_expiry_delta: MIN_CLTV_EXPIRY_DELTA,
 276                                         htlc_minimum_msat: None,
 277                                         htlc_maximum_msat: None,
 278                                 });
 279                                 hint
 280                         });
 281
 282                 phantom_hints.push(route_hints);
 283         }
 284
 285         // We have one vector per real node involved in creating the phantom invoice. To distribute
 286         // the hints across our real nodes we add one hint from each in turn until no node has any hints
 287         // left (if one node has more hints than any other, these will accumulate at the end of the
 288         // vector).
 289         rotate_through_iterators(phantom_hints)
 290 }
 291
 292 /// Draw items iteratively from multiple iterators.  The items are retrieved by index and
 293 /// rotates through the iterators - first the zero index then the first index then second index, etc.
 294 fn rotate_through_iterators<T, I: Iterator<Item = T>>(mut vecs: Vec<I>) -> impl Iterator<Item = T> {
 295         let mut iterations = 0;
 296
 297         core::iter::from_fn(move || {
 298                 let mut exhausted_iterators = 0;
 299                 loop {
 300                         if vecs.is_empty() {
 301                                 return None;
 302                         }
 303                         let next_idx = iterations % vecs.len();
 304                         iterations += 1;
 305                         if let Some(item) = vecs[next_idx].next() {
 306                                 return Some(item);
 307                         }
 308                         // exhausted_vectors increase when the "next_idx" vector is exhausted
 309                         exhausted_iterators += 1;
 310                         // The check for exhausted iterators gets reset to 0 after each yield of `Some()`
 311                         // The loop will return None when all of the nested iterators are exhausted
 312                         if exhausted_iterators == vecs.len() {
 313                                 return None;
 314                         }
 315                 }
 316         })
 317 }
 318
 319 #[cfg(feature = "std")]
 320 /// Utility to construct an invoice. Generally, unless you want to do something like a custom
 321 /// cltv_expiry, this is what you should be using to create an invoice. The reason being, this
 322 /// method stores the invoice's payment secret and preimage in `ChannelManager`, so (a) the user
 323 /// doesn't have to store preimage/payment secret information and (b) `ChannelManager` can verify
 324 /// that the payment secret is valid when the invoice is paid.
 325 ///
 326 /// `invoice_expiry_delta_secs` describes the number of seconds that the invoice is valid for
 327 /// in excess of the current time.
 328 ///
 329 /// You can specify a custom `min_final_cltv_expiry_delta`, or let LDK default it to
 330 /// [`MIN_FINAL_CLTV_EXPIRY_DELTA`]. The provided expiry must be at least [`MIN_FINAL_CLTV_EXPIRY_DELTA`].
 331 /// Note that LDK will add a buffer of 3 blocks to the delta to allow for up to a few new block
 332 /// confirmations during routing.
 333 ///
 334 /// [`MIN_FINAL_CLTV_EXPIRY_DETLA`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA
 335 pub fn create_invoice_from_channelmanager<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 336         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 337         network: Currency, amt_msat: Option<u64>, description: String, invoice_expiry_delta_secs: u32,
 338         min_final_cltv_expiry_delta: Option<u16>,
 339 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 340 where
 341         M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 342         T::Target: BroadcasterInterface,
 343         ES::Target: EntropySource,
 344         NS::Target: NodeSigner,
 345         SP::Target: SignerProvider,
 346         F::Target: FeeEstimator,
 347         R::Target: Router,
 348         L::Target: Logger,
 349 {
 350         use std::time::SystemTime;
 351         let duration = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)
 352                 .expect("for the foreseeable future this shouldn't happen");
 353         create_invoice_from_channelmanager_and_duration_since_epoch(
 354                 channelmanager, node_signer, logger, network, amt_msat,
 355                 description, duration, invoice_expiry_delta_secs, min_final_cltv_expiry_delta,
 356         )
 357 }
 358
 359 #[cfg(feature = "std")]
 360 /// Utility to construct an invoice. Generally, unless you want to do something like a custom
 361 /// cltv_expiry, this is what you should be using to create an invoice. The reason being, this
 362 /// method stores the invoice's payment secret and preimage in `ChannelManager`, so (a) the user
 363 /// doesn't have to store preimage/payment secret information and (b) `ChannelManager` can verify
 364 /// that the payment secret is valid when the invoice is paid.
 365 /// Use this variant if you want to pass the `description_hash` to the invoice.
 366 ///
 367 /// `invoice_expiry_delta_secs` describes the number of seconds that the invoice is valid for
 368 /// in excess of the current time.
 369 ///
 370 /// You can specify a custom `min_final_cltv_expiry_delta`, or let LDK default it to
 371 /// [`MIN_FINAL_CLTV_EXPIRY_DELTA`]. The provided expiry must be at least [`MIN_FINAL_CLTV_EXPIRY_DELTA`].
 372 /// Note that LDK will add a buffer of 3 blocks to the delta to allow for up to a few new block
 373 /// confirmations during routing.
 374 ///
 375 /// [`MIN_FINAL_CLTV_EXPIRY_DETLA`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA
 376 pub fn create_invoice_from_channelmanager_with_description_hash<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 377         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 378         network: Currency, amt_msat: Option<u64>, description_hash: Sha256,
 379         invoice_expiry_delta_secs: u32, min_final_cltv_expiry_delta: Option<u16>,
 380 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 381 where
 382         M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 383         T::Target: BroadcasterInterface,
 384         ES::Target: EntropySource,
 385         NS::Target: NodeSigner,
 386         SP::Target: SignerProvider,
 387         F::Target: FeeEstimator,
 388         R::Target: Router,
 389         L::Target: Logger,
 390 {
 391         use std::time::SystemTime;
 392
 393         let duration = SystemTime::now()
 394                 .duration_since(SystemTime::UNIX_EPOCH)
 395                 .expect("for the foreseeable future this shouldn't happen");
 396
 397         create_invoice_from_channelmanager_with_description_hash_and_duration_since_epoch(
 398                 channelmanager, node_signer, logger, network, amt_msat,
 399                 description_hash, duration, invoice_expiry_delta_secs, min_final_cltv_expiry_delta,
 400         )
 401 }
 402
 403 /// See [`create_invoice_from_channelmanager_with_description_hash`]
 404 /// This version can be used in a `no_std` environment, where [`std::time::SystemTime`] is not
 405 /// available and the current time is supplied by the caller.
 406 pub fn create_invoice_from_channelmanager_with_description_hash_and_duration_since_epoch<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 407         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 408         network: Currency, amt_msat: Option<u64>, description_hash: Sha256,
 409         duration_since_epoch: Duration, invoice_expiry_delta_secs: u32, min_final_cltv_expiry_delta: Option<u16>,
 410 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 411                 where
 412                         M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 413                         T::Target: BroadcasterInterface,
 414                         ES::Target: EntropySource,
 415                         NS::Target: NodeSigner,
 416                         SP::Target: SignerProvider,
 417                         F::Target: FeeEstimator,
 418                         R::Target: Router,
 419                         L::Target: Logger,
 420 {
 421         _create_invoice_from_channelmanager_and_duration_since_epoch(
 422                 channelmanager, node_signer, logger, network, amt_msat,
 423                 Bolt11InvoiceDescription::Hash(&description_hash),
 424                 duration_since_epoch, invoice_expiry_delta_secs, min_final_cltv_expiry_delta,
 425         )
 426 }
 427
 428 /// See [`create_invoice_from_channelmanager`]
 429 /// This version can be used in a `no_std` environment, where [`std::time::SystemTime`] is not
 430 /// available and the current time is supplied by the caller.
 431 pub fn create_invoice_from_channelmanager_and_duration_since_epoch<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 432         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 433         network: Currency, amt_msat: Option<u64>, description: String, duration_since_epoch: Duration,
 434         invoice_expiry_delta_secs: u32, min_final_cltv_expiry_delta: Option<u16>,
 435 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 436                 where
 437                         M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 438                         T::Target: BroadcasterInterface,
 439                         ES::Target: EntropySource,
 440                         NS::Target: NodeSigner,
 441                         SP::Target: SignerProvider,
 442                         F::Target: FeeEstimator,
 443                         R::Target: Router,
 444                         L::Target: Logger,
 445 {
 446         _create_invoice_from_channelmanager_and_duration_since_epoch(
 447                 channelmanager, node_signer, logger, network, amt_msat,
 448                 Bolt11InvoiceDescription::Direct(
 449                         &Description::new(description).map_err(SignOrCreationError::CreationError)?,
 450                 ),
 451                 duration_since_epoch, invoice_expiry_delta_secs, min_final_cltv_expiry_delta,
 452         )
 453 }
 454
 455 fn _create_invoice_from_channelmanager_and_duration_since_epoch<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 456         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 457         network: Currency, amt_msat: Option<u64>, description: Bolt11InvoiceDescription,
 458         duration_since_epoch: Duration, invoice_expiry_delta_secs: u32, min_final_cltv_expiry_delta: Option<u16>,
 459 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 460                 where
 461                         M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 462                         T::Target: BroadcasterInterface,
 463                         ES::Target: EntropySource,
 464                         NS::Target: NodeSigner,
 465                         SP::Target: SignerProvider,
 466                         F::Target: FeeEstimator,
 467                         R::Target: Router,
 468                         L::Target: Logger,
 469 {
 470         if min_final_cltv_expiry_delta.is_some() && min_final_cltv_expiry_delta.unwrap().saturating_add(3) < MIN_FINAL_CLTV_EXPIRY_DELTA {
 471                 return Err(SignOrCreationError::CreationError(CreationError::MinFinalCltvExpiryDeltaTooShort));
 472         }
 473
 474         // `create_inbound_payment` only returns an error if the amount is greater than the total bitcoin
 475         // supply.
 476         let (payment_hash, payment_secret) = channelmanager
 477                 .create_inbound_payment(amt_msat, invoice_expiry_delta_secs, min_final_cltv_expiry_delta)
 478                 .map_err(|()| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 479         _create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash(
 480                 channelmanager, node_signer, logger, network, amt_msat, description, duration_since_epoch,
 481                 invoice_expiry_delta_secs, payment_hash, payment_secret, min_final_cltv_expiry_delta)
 482 }
 483
 484 /// See [`create_invoice_from_channelmanager_and_duration_since_epoch`]
 485 /// This version allows for providing a custom [`PaymentHash`] for the invoice.
 486 /// This may be useful if you're building an on-chain swap or involving another protocol where
 487 /// the payment hash is also involved outside the scope of lightning.
 488 pub fn create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 489         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 490         network: Currency, amt_msat: Option<u64>, description: String, duration_since_epoch: Duration,
 491         invoice_expiry_delta_secs: u32, payment_hash: PaymentHash, min_final_cltv_expiry_delta: Option<u16>,
 492 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 493         where
 494                 M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 495                 T::Target: BroadcasterInterface,
 496                 ES::Target: EntropySource,
 497                 NS::Target: NodeSigner,
 498                 SP::Target: SignerProvider,
 499                 F::Target: FeeEstimator,
 500                 R::Target: Router,
 501                 L::Target: Logger,
 502 {
 503         let payment_secret = channelmanager
 504                 .create_inbound_payment_for_hash(payment_hash, amt_msat, invoice_expiry_delta_secs,
 505                         min_final_cltv_expiry_delta)
 506                 .map_err(|()| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 507         _create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash(
 508                 channelmanager, node_signer, logger, network, amt_msat,
 509                 Bolt11InvoiceDescription::Direct(
 510                         &Description::new(description).map_err(SignOrCreationError::CreationError)?,
 511                 ),
 512                 duration_since_epoch, invoice_expiry_delta_secs, payment_hash, payment_secret,
 513                 min_final_cltv_expiry_delta,
 514         )
 515 }
 516
 517 fn _create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>(
 518         channelmanager: &ChannelManager<M, T, ES, NS, SP, F, R, L>, node_signer: NS, logger: L,
 519         network: Currency, amt_msat: Option<u64>, description: Bolt11InvoiceDescription,
 520         duration_since_epoch: Duration, invoice_expiry_delta_secs: u32, payment_hash: PaymentHash,
 521         payment_secret: PaymentSecret, min_final_cltv_expiry_delta: Option<u16>,
 522 ) -> Result<Bolt11Invoice, SignOrCreationError<()>>
 523         where
 524                 M::Target: chain::Watch<<SP::Target as SignerProvider>::EcdsaSigner>,
 525                 T::Target: BroadcasterInterface,
 526                 ES::Target: EntropySource,
 527                 NS::Target: NodeSigner,
 528                 SP::Target: SignerProvider,
 529                 F::Target: FeeEstimator,
 530                 R::Target: Router,
 531                 L::Target: Logger,
 532 {
 533         let our_node_pubkey = channelmanager.get_our_node_id();
 534         let channels = channelmanager.list_channels();
 535
 536         if min_final_cltv_expiry_delta.is_some() && min_final_cltv_expiry_delta.unwrap().saturating_add(3) < MIN_FINAL_CLTV_EXPIRY_DELTA {
 537                 return Err(SignOrCreationError::CreationError(CreationError::MinFinalCltvExpiryDeltaTooShort));
 538         }
 539
 540         log_trace!(logger, "Creating invoice with payment hash {}", &payment_hash);
 541
 542         let invoice = match description {
 543                 Bolt11InvoiceDescription::Direct(description) => {
 544                         InvoiceBuilder::new(network).description(description.0.0.clone())
 545                 }
 546                 Bolt11InvoiceDescription::Hash(hash) => InvoiceBuilder::new(network).description_hash(hash.0),
 547         };
 548
 549         let mut invoice = invoice
 550                 .duration_since_epoch(duration_since_epoch)
 551                 .payee_pub_key(our_node_pubkey)
 552                 .payment_hash(Hash::from_slice(&payment_hash.0).unwrap())
 553                 .payment_secret(payment_secret)
 554                 .basic_mpp()
 555                 .min_final_cltv_expiry_delta(
 556                         // Add a buffer of 3 to the delta if present, otherwise use LDK's minimum.
 557                         min_final_cltv_expiry_delta.map(|x| x.saturating_add(3)).unwrap_or(MIN_FINAL_CLTV_EXPIRY_DELTA).into())
 558                 .expiry_time(Duration::from_secs(invoice_expiry_delta_secs.into()));
 559         if let Some(amt) = amt_msat {
 560                 invoice = invoice.amount_milli_satoshis(amt);
 561         }
 562
 563         let route_hints = sort_and_filter_channels(channels, amt_msat, &logger);
 564         for hint in route_hints {
 565                 invoice = invoice.private_route(hint);
 566         }
 567
 568         let raw_invoice = match invoice.build_raw() {
 569                 Ok(inv) => inv,
 570                 Err(e) => return Err(SignOrCreationError::CreationError(e))
 571         };
 572         let hrp_str = raw_invoice.hrp.to_string();
 573         let hrp_bytes = hrp_str.as_bytes();
 574         let data_without_signature = raw_invoice.data.to_base32();
 575         let signed_raw_invoice = raw_invoice.sign(|_| node_signer.sign_invoice(hrp_bytes, &data_without_signature, Recipient::Node));
 576         match signed_raw_invoice {
 577                 Ok(inv) => Ok(Bolt11Invoice::from_signed(inv).unwrap()),
 578                 Err(e) => Err(SignOrCreationError::SignError(e))
 579         }
 580 }
 581
 582 /// Sorts and filters the `channels` for an invoice, and returns the corresponding `RouteHint`s to include
 583 /// in the invoice.
 584 ///
 585 /// The filtering is based on the following criteria:
 586 /// * Only one channel per counterparty node
 587 /// * If the counterparty has a channel that is above the `min_inbound_capacity_msat` + 10% scaling
 588 ///   factor (to allow some margin for change in inbound), select the channel with the lowest
 589 ///   inbound capacity that is above this threshold.
 590 /// * If no `min_inbound_capacity_msat` is specified, or the counterparty has no channels above the
 591 ///   minimum + 10% scaling factor, select the channel with the highest inbound capacity per counterparty.
 592 /// * Prefer channels with capacity at least `min_inbound_capacity_msat` and where the channel
 593 ///   `is_usable` (i.e. the peer is connected).
 594 /// * If any public channel exists, only public [`RouteHint`]s will be returned.
 595 /// * If any public, announced, channel exists (i.e. a channel with 7+ confs, to ensure the
 596 ///   announcement has had a chance to propagate), no [`RouteHint`]s will be returned, as the
 597 ///   sender is expected to find the path by looking at the public channels instead.
 598 /// * Limited to a total of 3 channels.
 599 /// * Sorted by lowest inbound capacity if an online channel with the minimum amount requested exists,
 600 ///   otherwise sort by highest inbound capacity to give the payment the best chance of succeeding.
 601 fn sort_and_filter_channels<L: Deref>(
 602         channels: Vec<ChannelDetails>,
 603         min_inbound_capacity_msat: Option<u64>,
 604         logger: &L,
 605 ) -> impl ExactSizeIterator<Item = RouteHint>
 606 where
 607         L::Target: Logger,
 608 {
 609         let mut filtered_channels: BTreeMap<PublicKey, ChannelDetails> = BTreeMap::new();
 610         let min_inbound_capacity = min_inbound_capacity_msat.unwrap_or(0);
 611         let mut min_capacity_channel_exists = false;
 612         let mut online_channel_exists = false;
 613         let mut online_min_capacity_channel_exists = false;
 614         let mut has_pub_unconf_chan = false;
 615
 616         let route_hint_from_channel = |channel: ChannelDetails| {
 617                 let forwarding_info = channel.counterparty.forwarding_info.as_ref().unwrap();
 618                 RouteHint(vec![RouteHintHop {
 619                         src_node_id: channel.counterparty.node_id,
 620                         short_channel_id: channel.get_inbound_payment_scid().unwrap(),
 621                         fees: RoutingFees {
 622                                 base_msat: forwarding_info.fee_base_msat,
 623                                 proportional_millionths: forwarding_info.fee_proportional_millionths,
 624                         },
 625                         cltv_expiry_delta: forwarding_info.cltv_expiry_delta,
 626                         htlc_minimum_msat: channel.inbound_htlc_minimum_msat,
 627                         htlc_maximum_msat: channel.inbound_htlc_maximum_msat,}])
 628         };
 629
 630         log_trace!(logger, "Considering {} channels for invoice route hints", channels.len());
 631         for channel in channels.into_iter().filter(|chan| chan.is_channel_ready) {
 632                 let logger = WithChannelDetails::from(logger, &channel);
 633                 if channel.get_inbound_payment_scid().is_none() || channel.counterparty.forwarding_info.is_none() {
 634                         log_trace!(logger, "Ignoring channel {} for invoice route hints", &channel.channel_id);
 635                         continue;
 636                 }
 637
 638                 if channel.is_public {
 639                         if channel.confirmations.is_some() && channel.confirmations < Some(7) {
 640                                 // If we have a public channel, but it doesn't have enough confirmations to (yet)
 641                                 // be in the public network graph (and have gotten a chance to propagate), include
 642                                 // route hints but only for public channels to protect private channel privacy.
 643                                 has_pub_unconf_chan = true;
 644                         } else {
 645                                 // If any public channel exists, return no hints and let the sender
 646                                 // look at the public channels instead.
 647                                 log_trace!(logger, "Not including channels in invoice route hints on account of public channel {}",
 648                                         &channel.channel_id);
 649                                 return vec![].into_iter().take(MAX_CHANNEL_HINTS).map(route_hint_from_channel);
 650                         }
 651                 }
 652
 653                 if channel.inbound_capacity_msat >= min_inbound_capacity {
 654                         if !min_capacity_channel_exists {
 655                                 log_trace!(logger, "Channel with enough inbound capacity exists for invoice route hints");
 656                                 min_capacity_channel_exists = true;
 657                         }
 658
 659                         if channel.is_usable {
 660                                 online_min_capacity_channel_exists = true;
 661                         }
 662                 }
 663
 664                 if channel.is_usable && !online_channel_exists {
 665                         log_trace!(logger, "Channel with connected peer exists for invoice route hints");
 666                         online_channel_exists = true;
 667                 }
 668
 669                 match filtered_channels.entry(channel.counterparty.node_id) {
 670                         btree_map::Entry::Occupied(mut entry) => {
 671                                 let current_max_capacity = entry.get().inbound_capacity_msat;
 672                                 // If this channel is public and the previous channel is not, ensure we replace the
 673                                 // previous channel to avoid announcing non-public channels.
 674                                 let new_now_public = channel.is_public && !entry.get().is_public;
 675                                 // Decide whether we prefer the currently selected channel with the node to the new one,
 676                                 // based on their inbound capacity.
 677                                 let prefer_current = prefer_current_channel(min_inbound_capacity_msat, current_max_capacity,
 678                                         channel.inbound_capacity_msat);
 679                                 // If the public-ness of the channel has not changed (in which case simply defer to
 680                                 // `new_now_public), and this channel has more desirable inbound than the incumbent,
 681                                 // prefer to include this channel.
 682                                 let new_channel_preferable = channel.is_public == entry.get().is_public && !prefer_current;
 683
 684                                 if new_now_public || new_channel_preferable {
 685                                         log_trace!(logger,
 686                                                 "Preferring counterparty {} channel {} (SCID {:?}, {} msats) over {} (SCID {:?}, {} msats) for invoice route hints",
 687                                                 log_pubkey!(channel.counterparty.node_id),
 688                                                 &channel.channel_id, channel.short_channel_id,
 689                                                 channel.inbound_capacity_msat,
 690                                                 &entry.get().channel_id, entry.get().short_channel_id,
 691                                                 current_max_capacity);
 692                                         entry.insert(channel);
 693                                 } else {
 694                                         log_trace!(logger,
 695                                                 "Preferring counterparty {} channel {} (SCID {:?}, {} msats) over {} (SCID {:?}, {} msats) for invoice route hints",
 696                                                 log_pubkey!(channel.counterparty.node_id),
 697                                                 &entry.get().channel_id, entry.get().short_channel_id,
 698                                                 current_max_capacity,
 699                                                 &channel.channel_id, channel.short_channel_id,
 700                                                 channel.inbound_capacity_msat);
 701                                 }
 702                         }
 703                         btree_map::Entry::Vacant(entry) => {
 704                                 entry.insert(channel);
 705                         }
 706                 }
 707         }
 708
 709         // If all channels are private, prefer to return route hints which have a higher capacity than
 710         // the payment value and where we're currently connected to the channel counterparty.
 711         // Even if we cannot satisfy both goals, always ensure we include *some* hints, preferring
 712         // those which meet at least one criteria.
 713         let mut eligible_channels = filtered_channels
 714                 .into_iter()
 715                 .map(|(_, channel)| channel)
 716                 .filter(|channel| {
 717                         let logger = WithChannelDetails::from(logger, &channel);
 718                         let has_enough_capacity = channel.inbound_capacity_msat >= min_inbound_capacity;
 719                         let include_channel = if has_pub_unconf_chan {
 720                                 // If we have a public channel, but it doesn't have enough confirmations to (yet)
 721                                 // be in the public network graph (and have gotten a chance to propagate), include
 722                                 // route hints but only for public channels to protect private channel privacy.
 723                                 channel.is_public
 724                         } else if online_min_capacity_channel_exists {
 725                                 has_enough_capacity && channel.is_usable
 726                         } else if min_capacity_channel_exists && online_channel_exists {
 727                                 // If there are some online channels and some min_capacity channels, but no
 728                                 // online-and-min_capacity channels, just include the min capacity ones and ignore
 729                                 // online-ness.
 730                                 has_enough_capacity
 731                         } else if min_capacity_channel_exists {
 732                                 has_enough_capacity
 733                         } else if online_channel_exists {
 734                                 channel.is_usable
 735                         } else { true };
 736
 737                         if include_channel {
 738                                 log_trace!(logger, "Including channel {} in invoice route hints",
 739                                         &channel.channel_id);
 740                         } else if !has_enough_capacity {
 741                                 log_trace!(logger, "Ignoring channel {} without enough capacity for invoice route hints",
 742                                         &channel.channel_id);
 743                         } else {
 744                                 debug_assert!(!channel.is_usable || (has_pub_unconf_chan && !channel.is_public));
 745                                 log_trace!(logger, "Ignoring channel {} with disconnected peer",
 746                                         &channel.channel_id);
 747                         }
 748
 749                         include_channel
 750                 })
 751                 .collect::<Vec<ChannelDetails>>();
 752
 753                 eligible_channels.sort_unstable_by(|a, b| {
 754                         if online_min_capacity_channel_exists {
 755                                 a.inbound_capacity_msat.cmp(&b.inbound_capacity_msat)
 756                         } else {
 757                                 b.inbound_capacity_msat.cmp(&a.inbound_capacity_msat)
 758                         }});
 759
 760                 eligible_channels.into_iter().take(MAX_CHANNEL_HINTS).map(route_hint_from_channel)
 761 }
 762
 763 /// prefer_current_channel chooses a channel to use for route hints between a currently selected and candidate
 764 /// channel based on the inbound capacity of each channel and the minimum inbound capacity requested for the hints,
 765 /// returning true if the current channel should be preferred over the candidate channel.
 766 /// * If no minimum amount is requested, the channel with the most inbound is chosen to maximize the chances that a
 767 ///   payment of any size will succeed.
 768 /// * If we have channels with inbound above our minimum requested inbound (plus a 10% scaling factor, expressed as a
 769 ///   percentage) then we choose the lowest inbound channel with above this amount. If we have sufficient inbound
 770 ///   channels, we don't want to deplete our larger channels with small payments (the off-chain version of "grinding
 771 ///   our change").
 772 /// * If no channel above our minimum amount exists, then we just prefer the channel with the most inbound to give
 773 ///   payments the best chance of succeeding in multiple parts.
 774 fn prefer_current_channel(min_inbound_capacity_msat: Option<u64>, current_channel: u64,
 775         candidate_channel: u64) -> bool {
 776
 777         // If no min amount is given for the hints, err of the side of caution and choose the largest channel inbound to
 778         // maximize chances of any payment succeeding.
 779         if min_inbound_capacity_msat.is_none() {
 780                 return current_channel > candidate_channel
 781         }
 782
 783         let scaled_min_inbound = min_inbound_capacity_msat.unwrap() * 110;
 784         let current_sufficient = current_channel * 100 >= scaled_min_inbound;
 785         let candidate_sufficient = candidate_channel * 100 >= scaled_min_inbound;
 786
 787         if current_sufficient && candidate_sufficient {
 788                 return current_channel < candidate_channel
 789         } else if current_sufficient {
 790                 return true
 791         } else if candidate_sufficient {
 792                 return false
 793         }
 794
 795         current_channel > candidate_channel
 796 }
 797
 798 /// Adds relevant context to a [`Record`] before passing it to the wrapped [`Logger`].
 799 struct WithChannelDetails<'a, 'b, L: Deref> where L::Target: Logger {
 800         /// The logger to delegate to after adding context to the record.
 801         logger: &'a L,
 802         /// The [`ChannelDetails`] for adding relevant context to the logged record.
 803         details: &'b ChannelDetails
 804 }
 805
 806 impl<'a, 'b, L: Deref> Logger for WithChannelDetails<'a, 'b, L> where L::Target: Logger {
 807         fn log(&self, mut record: Record) {
 808                 record.peer_id = Some(self.details.counterparty.node_id);
 809                 record.channel_id = Some(self.details.channel_id);
 810                 self.logger.log(record)
 811         }
 812 }
 813
 814 impl<'a, 'b, L: Deref> WithChannelDetails<'a, 'b, L> where L::Target: Logger {
 815         fn from(logger: &'a L, details: &'b ChannelDetails) -> Self {
 816                 Self { logger, details }
 817         }
 818 }
 819
 820 #[cfg(test)]
 821 mod test {
 822         use core::time::Duration;
 823         use crate::{Currency, Description, Bolt11InvoiceDescription, SignOrCreationError, CreationError};
 824         use bitcoin::hashes::{Hash, sha256};
 825         use bitcoin::hashes::sha256::Hash as Sha256;
 826         use lightning::sign::PhantomKeysManager;
 827         use lightning::events::{MessageSendEvent, MessageSendEventsProvider};
 828         use lightning::ln::types::PaymentHash;
 829         #[cfg(feature = "std")]
 830         use lightning::ln::types::PaymentPreimage;
 831         use lightning::ln::channelmanager::{PhantomRouteHints, MIN_FINAL_CLTV_EXPIRY_DELTA, PaymentId, RecipientOnionFields, Retry};
 832         use lightning::ln::functional_test_utils::*;
 833         use lightning::ln::msgs::ChannelMessageHandler;
 834         use lightning::routing::router::{PaymentParameters, RouteParameters};
 835         use lightning::util::test_utils;
 836         use lightning::util::config::UserConfig;
 837         use crate::utils::{create_invoice_from_channelmanager_and_duration_since_epoch, rotate_through_iterators};
 838         use std::collections::HashSet;
 839         use lightning::util::string::UntrustedString;
 840
 841         #[test]
 842         fn test_prefer_current_channel() {
 843                 // No minimum, prefer larger candidate channel.
 844                 assert_eq!(crate::utils::prefer_current_channel(None, 100, 200), false);
 845
 846                 // No minimum, prefer larger current channel.
 847                 assert_eq!(crate::utils::prefer_current_channel(None, 200, 100), true);
 848
 849                 // Minimum set, prefer current channel over minimum + buffer.
 850                 assert_eq!(crate::utils::prefer_current_channel(Some(100), 115, 100), true);
 851
 852                 // Minimum set, prefer candidate channel over minimum + buffer.
 853                 assert_eq!(crate::utils::prefer_current_channel(Some(100), 105, 125), false);
 854
 855                 // Minimum set, both channels sufficient, prefer smaller current channel.
 856                 assert_eq!(crate::utils::prefer_current_channel(Some(100), 115, 125), true);
 857
 858                 // Minimum set, both channels sufficient, prefer smaller candidate channel.
 859                 assert_eq!(crate::utils::prefer_current_channel(Some(100), 200, 160), false);
 860
 861                 // Minimum set, neither sufficient, prefer larger current channel.
 862                 assert_eq!(crate::utils::prefer_current_channel(Some(200), 100, 50), true);
 863
 864                 // Minimum set, neither sufficient, prefer larger candidate channel.
 865                 assert_eq!(crate::utils::prefer_current_channel(Some(200), 100, 150), false);
 866         }
 867
 868
 869         #[test]
 870         fn test_from_channelmanager() {
 871                 let chanmon_cfgs = create_chanmon_cfgs(2);
 872                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 873                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 874                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 875                 create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001);
 876                 let non_default_invoice_expiry_secs = 4200;
 877                 let invoice = create_invoice_from_channelmanager_and_duration_since_epoch(
 878                         nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::BitcoinTestnet,
 879                         Some(10_000), "test".to_string(), Duration::from_secs(1234567),
 880                         non_default_invoice_expiry_secs, None).unwrap();
 881                 assert_eq!(invoice.amount_pico_btc(), Some(100_000));
 882                 // If no `min_final_cltv_expiry_delta` is specified, then it should be `MIN_FINAL_CLTV_EXPIRY_DELTA`.
 883                 assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
 884                 assert_eq!(invoice.description(), Bolt11InvoiceDescription::Direct(&Description(UntrustedString("test".to_string()))));
 885                 assert_eq!(invoice.expiry_time(), Duration::from_secs(non_default_invoice_expiry_secs.into()));
 886
 887                 // Invoice SCIDs should always use inbound SCID aliases over the real channel ID, if one is
 888                 // available.
 889                 let chan = &nodes[1].node.list_usable_channels()[0];
 890                 assert_eq!(invoice.route_hints().len(), 1);
 891                 assert_eq!(invoice.route_hints()[0].0.len(), 1);
 892                 assert_eq!(invoice.route_hints()[0].0[0].short_channel_id, chan.inbound_scid_alias.unwrap());
 893
 894                 assert_eq!(invoice.route_hints()[0].0[0].htlc_minimum_msat, chan.inbound_htlc_minimum_msat);
 895                 assert_eq!(invoice.route_hints()[0].0[0].htlc_maximum_msat, chan.inbound_htlc_maximum_msat);
 896
 897                 let payment_params = PaymentParameters::from_node_id(invoice.recover_payee_pub_key(),
 898                                 invoice.min_final_cltv_expiry_delta() as u32)
 899                         .with_bolt11_features(invoice.features().unwrap().clone()).unwrap()
 900                         .with_route_hints(invoice.route_hints()).unwrap();
 901                 let route_params = RouteParameters::from_payment_params_and_value(
 902                         payment_params, invoice.amount_milli_satoshis().unwrap());
 903                 let payment_event = {
 904                         let payment_hash = PaymentHash(invoice.payment_hash().to_byte_array());
 905                         nodes[0].node.send_payment(payment_hash,
 906                                 RecipientOnionFields::secret_only(*invoice.payment_secret()),
 907                                 PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
 908                         let mut added_monitors = nodes[0].chain_monitor.added_monitors.lock().unwrap();
 909                         assert_eq!(added_monitors.len(), 1);
 910                         added_monitors.clear();
 911
 912                         let mut events = nodes[0].node.get_and_clear_pending_msg_events();
 913                         assert_eq!(events.len(), 1);
 914                         SendEvent::from_event(events.remove(0))
 915
 916                 };
 917                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
 918                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &payment_event.commitment_msg);
 919                 let mut added_monitors = nodes[1].chain_monitor.added_monitors.lock().unwrap();
 920                 assert_eq!(added_monitors.len(), 1);
 921                 added_monitors.clear();
 922                 let events = nodes[1].node.get_and_clear_pending_msg_events();
 923                 assert_eq!(events.len(), 2);
 924         }
 925
 926         fn do_create_invoice_min_final_cltv_delta(with_custom_delta: bool) {
 927                 let chanmon_cfgs = create_chanmon_cfgs(2);
 928                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 929                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 930                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 931                 let custom_min_final_cltv_expiry_delta = Some(50);
 932
 933                 let invoice = crate::utils::create_invoice_from_channelmanager_and_duration_since_epoch(
 934                         nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::BitcoinTestnet,
 935                         Some(10_000), "".into(), Duration::from_secs(1234567), 3600,
 936                         if with_custom_delta { custom_min_final_cltv_expiry_delta } else { None },
 937                 ).unwrap();
 938                 assert_eq!(invoice.min_final_cltv_expiry_delta(), if with_custom_delta {
 939                         custom_min_final_cltv_expiry_delta.unwrap() + 3 /* Buffer */} else { MIN_FINAL_CLTV_EXPIRY_DELTA } as u64);
 940         }
 941
 942         #[test]
 943         fn test_create_invoice_custom_min_final_cltv_delta() {
 944                 do_create_invoice_min_final_cltv_delta(true);
 945                 do_create_invoice_min_final_cltv_delta(false);
 946         }
 947
 948         #[test]
 949         fn create_invoice_min_final_cltv_delta_equals_htlc_fail_buffer() {
 950                 let chanmon_cfgs = create_chanmon_cfgs(2);
 951                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 952                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 953                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 954                 let custom_min_final_cltv_expiry_delta = Some(21);
 955
 956                 let invoice = crate::utils::create_invoice_from_channelmanager_and_duration_since_epoch(
 957                         nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::BitcoinTestnet,
 958                         Some(10_000), "".into(), Duration::from_secs(1234567), 3600,
 959                         custom_min_final_cltv_expiry_delta,
 960                 ).unwrap();
 961                 assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
 962         }
 963
 964         #[test]
 965         fn test_create_invoice_with_description_hash() {
 966                 let chanmon_cfgs = create_chanmon_cfgs(2);
 967                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 968                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 969                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 970                 let description_hash = crate::Sha256(Hash::hash("Testing description_hash".as_bytes()));
 971                 let invoice = crate::utils::create_invoice_from_channelmanager_with_description_hash_and_duration_since_epoch(
 972                         nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::BitcoinTestnet,
 973                         Some(10_000), description_hash, Duration::from_secs(1234567), 3600, None,
 974                 ).unwrap();
 975                 assert_eq!(invoice.amount_pico_btc(), Some(100_000));
 976                 assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
 977                 assert_eq!(invoice.description(), Bolt11InvoiceDescription::Hash(&crate::Sha256(Sha256::hash("Testing description_hash".as_bytes()))));
 978         }
 979
 980         #[test]
 981         fn test_create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash() {
 982                 let chanmon_cfgs = create_chanmon_cfgs(2);
 983                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 984                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 985                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 986                 let payment_hash = PaymentHash([0; 32]);
 987                 let invoice = crate::utils::create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash(
 988                         nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::BitcoinTestnet,
 989                         Some(10_000), "test".to_string(), Duration::from_secs(1234567), 3600,
 990                         payment_hash, None,
 991                 ).unwrap();
 992                 assert_eq!(invoice.amount_pico_btc(), Some(100_000));
 993                 assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
 994                 assert_eq!(invoice.description(), Bolt11InvoiceDescription::Direct(&Description(UntrustedString("test".to_string()))));
 995                 assert_eq!(invoice.payment_hash(), &sha256::Hash::from_slice(&payment_hash.0[..]).unwrap());
 996         }
 997
 998         #[test]
 999         fn test_hints_has_only_public_confd_channels() {
1000                 let chanmon_cfgs = create_chanmon_cfgs(2);
1001                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1002                 let mut config = test_default_channel_config();
1003                 config.channel_handshake_config.minimum_depth = 1;
1004                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[Some(config), Some(config)]);
1005                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1006
1007                 // Create a private channel with lots of capacity and a lower value public channel (without
1008                 // confirming the funding tx yet).
1009                 let unannounced_scid = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0);
1010                 let conf_tx = create_chan_between_nodes_with_value_init(&nodes[0], &nodes[1], 10_000, 0);
1011
1012                 // Before the channel is available, we should include the unannounced_scid.
1013                 let mut scid_aliases = HashSet::new();
1014                 scid_aliases.insert(unannounced_scid.0.short_channel_id_alias.unwrap());
1015                 match_invoice_routes(Some(5000), &nodes[1], scid_aliases.clone());
1016
1017                 // However after we mine the funding tx and exchange channel_ready messages for the public
1018                 // channel we'll immediately switch to including it as a route hint, even though it isn't
1019                 // yet announced.
1020                 let pub_channel_scid = mine_transaction(&nodes[0], &conf_tx);
1021                 let node_a_pub_channel_ready = get_event_msg!(nodes[0], MessageSendEvent::SendChannelReady, nodes[1].node.get_our_node_id());
1022                 nodes[1].node.handle_channel_ready(&nodes[0].node.get_our_node_id(), &node_a_pub_channel_ready);
1023
1024                 assert_eq!(mine_transaction(&nodes[1], &conf_tx), pub_channel_scid);
1025                 let events = nodes[1].node.get_and_clear_pending_msg_events();
1026                 assert_eq!(events.len(), 2);
1027                 if let MessageSendEvent::SendChannelReady { msg, .. } = &events[0] {
1028                         nodes[0].node.handle_channel_ready(&nodes[1].node.get_our_node_id(), msg);
1029                 } else { panic!(); }
1030                 if let MessageSendEvent::SendChannelUpdate { msg, .. } = &events[1] {
1031                         nodes[0].node.handle_channel_update(&nodes[1].node.get_our_node_id(), msg);
1032                 } else { panic!(); }
1033
1034                 nodes[1].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &get_event_msg!(nodes[0], MessageSendEvent::SendChannelUpdate, nodes[1].node.get_our_node_id()));
1035
1036                 expect_channel_ready_event(&nodes[0], &nodes[1].node.get_our_node_id());
1037                 expect_channel_ready_event(&nodes[1], &nodes[0].node.get_our_node_id());
1038
1039                 scid_aliases.clear();
1040                 scid_aliases.insert(node_a_pub_channel_ready.short_channel_id_alias.unwrap());
1041                 match_invoice_routes(Some(5000), &nodes[1], scid_aliases.clone());
1042                 // This also applies even if the amount is more than the payment amount, to ensure users
1043                 // dont screw up their privacy.
1044                 match_invoice_routes(Some(50_000_000), &nodes[1], scid_aliases.clone());
1045
1046                 // The same remains true until the channel has 7 confirmations, at which point we include
1047                 // no hints.
1048                 connect_blocks(&nodes[1], 5);
1049                 match_invoice_routes(Some(5000), &nodes[1], scid_aliases.clone());
1050                 connect_blocks(&nodes[1], 1);
1051                 get_event_msg!(nodes[1], MessageSendEvent::SendAnnouncementSignatures, nodes[0].node.get_our_node_id());
1052                 match_invoice_routes(Some(5000), &nodes[1], HashSet::new());
1053         }
1054
1055         #[test]
1056         fn test_hints_includes_single_channels_to_nodes() {
1057                 let chanmon_cfgs = create_chanmon_cfgs(3);
1058                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1059                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1060                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1061
1062                 let chan_1_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100000, 10001);
1063                 let chan_2_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 0, 100000, 10001);
1064
1065                 let mut scid_aliases = HashSet::new();
1066                 scid_aliases.insert(chan_1_0.0.short_channel_id_alias.unwrap());
1067                 scid_aliases.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1068
1069                 match_invoice_routes(Some(5000), &nodes[0], scid_aliases);
1070         }
1071
1072         #[test]
1073         fn test_hints_has_only_lowest_inbound_capacity_channel_above_minimum() {
1074                 let chanmon_cfgs = create_chanmon_cfgs(2);
1075                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1076                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
1077                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1078
1079                 let _chan_1_0_inbound_below_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 10_000, 0);
1080                 let _chan_1_0_large_inbound_above_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 500_000, 0);
1081                 let chan_1_0_low_inbound_above_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 200_000, 0);
1082
1083                 let mut scid_aliases = HashSet::new();
1084                 scid_aliases.insert(chan_1_0_low_inbound_above_amt.0.short_channel_id_alias.unwrap());
1085                 match_invoice_routes(Some(100_000_000), &nodes[0], scid_aliases);
1086         }
1087
1088         #[test]
1089         fn test_hints_has_only_online_channels() {
1090                 let chanmon_cfgs = create_chanmon_cfgs(4);
1091                 let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
1092                 let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
1093                 let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
1094                 let chan_a = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 10_000_000, 0);
1095                 let chan_b = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 0, 10_000_000, 0);
1096                 let _chan_c = create_unannounced_chan_between_nodes_with_value(&nodes, 3, 0, 1_000_000, 0);
1097
1098                 // With all peers connected we should get all hints that have sufficient value
1099                 let mut scid_aliases = HashSet::new();
1100                 scid_aliases.insert(chan_a.0.short_channel_id_alias.unwrap());
1101                 scid_aliases.insert(chan_b.0.short_channel_id_alias.unwrap());
1102
1103                 match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases.clone());
1104
1105                 // With only one sufficient-value peer connected we should only get its hint
1106                 scid_aliases.remove(&chan_b.0.short_channel_id_alias.unwrap());
1107                 nodes[0].node.peer_disconnected(&nodes[2].node.get_our_node_id());
1108                 match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases.clone());
1109
1110                 // If we don't have any sufficient-value peers connected we should get all hints with
1111                 // sufficient value, even though there is a connected insufficient-value peer.
1112                 scid_aliases.insert(chan_b.0.short_channel_id_alias.unwrap());
1113                 nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
1114                 match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases);
1115         }
1116
1117         #[test]
1118         fn test_insufficient_inbound_sort_by_highest_capacity() {
1119                 let chanmon_cfgs = create_chanmon_cfgs(5);
1120                 let node_cfgs = create_node_cfgs(5, &chanmon_cfgs);
1121                 let node_chanmgrs = create_node_chanmgrs(5, &node_cfgs, &[None, None, None, None, None]);
1122                 let nodes = create_network(5, &node_cfgs, &node_chanmgrs);
1123                 let _chan_1_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100_000, 0);
1124                 let chan_2_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 0, 200_000, 0);
1125                 let chan_3_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 3, 0, 300_000, 0);
1126                 let chan_4_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 4, 0, 400_000, 0);
1127
1128                 // When no single channel has enough inbound capacity for the payment, we expect the three
1129                 // highest inbound channels to be chosen.
1130                 let mut scid_aliases = HashSet::new();
1131                 scid_aliases.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1132                 scid_aliases.insert(chan_3_0.0.short_channel_id_alias.unwrap());
1133                 scid_aliases.insert(chan_4_0.0.short_channel_id_alias.unwrap());
1134
1135                 match_invoice_routes(Some(1_000_000_000), &nodes[0], scid_aliases.clone());
1136         }
1137
1138         #[test]
1139         fn test_sufficient_inbound_sort_by_lowest_capacity() {
1140                 let chanmon_cfgs = create_chanmon_cfgs(5);
1141                 let node_cfgs = create_node_cfgs(5, &chanmon_cfgs);
1142                 let node_chanmgrs = create_node_chanmgrs(5, &node_cfgs, &[None, None, None, None, None]);
1143                 let nodes = create_network(5, &node_cfgs, &node_chanmgrs);
1144                 let chan_1_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100_000, 0);
1145                 let chan_2_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 0, 200_000, 0);
1146                 let chan_3_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 3, 0, 300_000, 0);
1147                 let _chan_4_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 4, 0, 400_000, 0);
1148
1149                 // When we have channels that have sufficient inbound for the payment, test that we sort
1150                 // by lowest inbound capacity.
1151                 let mut scid_aliases = HashSet::new();
1152                 scid_aliases.insert(chan_1_0.0.short_channel_id_alias.unwrap());
1153                 scid_aliases.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1154                 scid_aliases.insert(chan_3_0.0.short_channel_id_alias.unwrap());
1155
1156                 match_invoice_routes(Some(50_000_000), &nodes[0], scid_aliases.clone());
1157         }
1158
1159         #[test]
1160         fn test_forwarding_info_not_assigned_channel_excluded_from_hints() {
1161                 let chanmon_cfgs = create_chanmon_cfgs(3);
1162                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1163                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1164                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1165                 let chan_1_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100000, 10001);
1166
1167                 // Create an unannonced channel between `nodes[2]` and `nodes[0]`, for which the
1168                 // `msgs::ChannelUpdate` is never handled for the node(s). As the `msgs::ChannelUpdate`
1169                 // is never handled, the `channel.counterparty.forwarding_info` is never assigned.
1170                 let mut private_chan_cfg = UserConfig::default();
1171                 private_chan_cfg.channel_handshake_config.announced_channel = false;
1172                 let temporary_channel_id = nodes[2].node.create_channel(nodes[0].node.get_our_node_id(), 1_000_000, 500_000_000, 42, None, Some(private_chan_cfg)).unwrap();
1173                 let open_channel = get_event_msg!(nodes[2], MessageSendEvent::SendOpenChannel, nodes[0].node.get_our_node_id());
1174                 nodes[0].node.handle_open_channel(&nodes[2].node.get_our_node_id(), &open_channel);
1175                 let accept_channel = get_event_msg!(nodes[0], MessageSendEvent::SendAcceptChannel, nodes[2].node.get_our_node_id());
1176                 nodes[2].node.handle_accept_channel(&nodes[0].node.get_our_node_id(), &accept_channel);
1177
1178                 let tx = sign_funding_transaction(&nodes[2], &nodes[0], 1_000_000, temporary_channel_id);
1179
1180                 let conf_height = core::cmp::max(nodes[2].best_block_info().1 + 1, nodes[0].best_block_info().1 + 1);
1181                 confirm_transaction_at(&nodes[2], &tx, conf_height);
1182                 connect_blocks(&nodes[2], CHAN_CONFIRM_DEPTH - 1);
1183                 confirm_transaction_at(&nodes[0], &tx, conf_height);
1184                 connect_blocks(&nodes[0], CHAN_CONFIRM_DEPTH - 1);
1185                 let as_channel_ready = get_event_msg!(nodes[2], MessageSendEvent::SendChannelReady, nodes[0].node.get_our_node_id());
1186                 nodes[2].node.handle_channel_ready(&nodes[0].node.get_our_node_id(), &get_event_msg!(nodes[0], MessageSendEvent::SendChannelReady, nodes[2].node.get_our_node_id()));
1187                 get_event_msg!(nodes[2], MessageSendEvent::SendChannelUpdate, nodes[0].node.get_our_node_id());
1188                 nodes[0].node.handle_channel_ready(&nodes[2].node.get_our_node_id(), &as_channel_ready);
1189                 get_event_msg!(nodes[0], MessageSendEvent::SendChannelUpdate, nodes[2].node.get_our_node_id());
1190                 expect_channel_ready_event(&nodes[0], &nodes[2].node.get_our_node_id());
1191                 expect_channel_ready_event(&nodes[2], &nodes[0].node.get_our_node_id());
1192
1193                 // As `msgs::ChannelUpdate` was never handled for the participating node(s) of the second
1194                 // channel, the channel will never be assigned any `counterparty.forwarding_info`.
1195                 // Therefore only `chan_1_0` should be included in the hints.
1196                 let mut scid_aliases = HashSet::new();
1197                 scid_aliases.insert(chan_1_0.0.short_channel_id_alias.unwrap());
1198                 match_invoice_routes(Some(5000), &nodes[0], scid_aliases);
1199         }
1200
1201         #[test]
1202         fn test_no_hints_if_a_mix_between_public_and_private_channel_exists() {
1203                 let chanmon_cfgs = create_chanmon_cfgs(3);
1204                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1205                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1206                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1207                 let _chan_1_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100000, 10001);
1208
1209                 let chan_2_0 = create_announced_chan_between_nodes_with_value(&nodes, 2, 0, 100000, 10001);
1210                 nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_2_0.1);
1211                 nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_2_0.0);
1212
1213                 // Ensure that the invoice doesn't include any route hints for any of `nodes[0]` channels,
1214                 // even though all channels between `nodes[1]` and `nodes[0]` are private, as there is a
1215                 // public channel between `nodes[2]` and `nodes[0]`
1216                 match_invoice_routes(Some(5000), &nodes[0], HashSet::new());
1217         }
1218
1219         #[test]
1220         fn test_only_public_channels_includes_no_channels_in_hints() {
1221                 let chanmon_cfgs = create_chanmon_cfgs(3);
1222                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1223                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1224                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1225                 let chan_1_0 = create_announced_chan_between_nodes_with_value(&nodes, 1, 0, 100000, 10001);
1226                 nodes[0].node.handle_channel_update(&nodes[1].node.get_our_node_id(), &chan_1_0.0);
1227                 nodes[1].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_1_0.1);
1228
1229                 let chan_2_0 = create_announced_chan_between_nodes_with_value(&nodes, 2, 0, 100000, 10001);
1230                 nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_2_0.1);
1231                 nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_2_0.0);
1232
1233                 // As all of `nodes[0]` channels are public, no channels should be included in the hints
1234                 match_invoice_routes(Some(5000), &nodes[0], HashSet::new());
1235         }
1236
1237         #[test]
1238         fn test_channels_with_lower_inbound_capacity_than_invoice_amt_hints_filtering() {
1239                 let chanmon_cfgs = create_chanmon_cfgs(3);
1240                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1241                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1242                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1243                 let chan_1_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100_000, 0);
1244                 let chan_2_0 = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 0, 1_000_000, 0);
1245
1246                 // As the invoice amt is 1 msat above chan_1_0's inbound capacity, it shouldn't be included
1247                 let mut scid_aliases_99_000_001_msat = HashSet::new();
1248                 scid_aliases_99_000_001_msat.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1249
1250                 match_invoice_routes(Some(99_000_001), &nodes[0], scid_aliases_99_000_001_msat);
1251
1252                 // As the invoice amt is exactly at chan_1_0's inbound capacity, it should be included
1253                 let mut scid_aliases_99_000_000_msat = HashSet::new();
1254                 scid_aliases_99_000_000_msat.insert(chan_1_0.0.short_channel_id_alias.unwrap());
1255                 scid_aliases_99_000_000_msat.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1256
1257                 match_invoice_routes(Some(99_000_000), &nodes[0], scid_aliases_99_000_000_msat);
1258
1259                 // As the invoice amt is above all channels' inbound capacity, they will still be included
1260                 let mut scid_aliases_2_000_000_000_msat = HashSet::new();
1261                 scid_aliases_2_000_000_000_msat.insert(chan_1_0.0.short_channel_id_alias.unwrap());
1262                 scid_aliases_2_000_000_000_msat.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1263
1264                 match_invoice_routes(Some(2_000_000_000), &nodes[0], scid_aliases_2_000_000_000_msat);
1265
1266                 // An invoice with no specified amount should include all channels in the route hints.
1267                 let mut scid_aliases_no_specified_amount = HashSet::new();
1268                 scid_aliases_no_specified_amount.insert(chan_1_0.0.short_channel_id_alias.unwrap());
1269                 scid_aliases_no_specified_amount.insert(chan_2_0.0.short_channel_id_alias.unwrap());
1270
1271                 match_invoice_routes(None, &nodes[0], scid_aliases_no_specified_amount);
1272         }
1273
1274         fn match_invoice_routes<'a, 'b: 'a, 'c: 'b>(
1275                 invoice_amt: Option<u64>,
1276                 invoice_node: &Node<'a, 'b, 'c>,
1277                 mut chan_ids_to_match: HashSet<u64>
1278         ) {
1279                 let invoice = create_invoice_from_channelmanager_and_duration_since_epoch(
1280                         invoice_node.node, invoice_node.keys_manager, invoice_node.logger,
1281                         Currency::BitcoinTestnet, invoice_amt, "test".to_string(), Duration::from_secs(1234567),
1282                         3600, None).unwrap();
1283                 let hints = invoice.private_routes();
1284
1285                 for hint in hints {
1286                         let hint_short_chan_id = (hint.0).0[0].short_channel_id;
1287                         assert!(chan_ids_to_match.remove(&hint_short_chan_id));
1288                 }
1289                 assert!(chan_ids_to_match.is_empty(), "Unmatched short channel ids: {:?}", chan_ids_to_match);
1290         }
1291
1292         #[test]
1293         #[cfg(feature = "std")]
1294         fn test_multi_node_receive() {
1295                 do_test_multi_node_receive(true);
1296                 do_test_multi_node_receive(false);
1297         }
1298
1299         #[cfg(feature = "std")]
1300         fn do_test_multi_node_receive(user_generated_pmt_hash: bool) {
1301                 use lightning::events::{Event, EventsProvider};
1302                 use core::cell::RefCell;
1303
1304                 let mut chanmon_cfgs = create_chanmon_cfgs(3);
1305                 let seed_1 = [42u8; 32];
1306                 let seed_2 = [43u8; 32];
1307                 let cross_node_seed = [44u8; 32];
1308                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1309                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1310                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1311                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1312                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1313                 let chan_0_1 = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001);
1314                 nodes[0].node.handle_channel_update(&nodes[1].node.get_our_node_id(), &chan_0_1.1);
1315                 nodes[1].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_1.0);
1316                 let chan_0_2 = create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1317                 nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_0_2.1);
1318                 nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_2.0);
1319
1320                 let payment_amt = 10_000;
1321                 let route_hints = vec![
1322                         nodes[1].node.get_phantom_route_hints(),
1323                         nodes[2].node.get_phantom_route_hints(),
1324                 ];
1325
1326                 let user_payment_preimage = PaymentPreimage([1; 32]);
1327                 let payment_hash = if user_generated_pmt_hash {
1328                         Some(PaymentHash(Sha256::hash(&user_payment_preimage.0[..]).to_byte_array()))
1329                 } else {
1330                         None
1331                 };
1332                 let genesis_timestamp = bitcoin::blockdata::constants::genesis_block(bitcoin::Network::Testnet).header.time as u64;
1333                 let non_default_invoice_expiry_secs = 4200;
1334
1335                 let invoice =
1336                         crate::utils::create_phantom_invoice::<&test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestLogger>(
1337                                 Some(payment_amt), payment_hash, "test".to_string(), non_default_invoice_expiry_secs,
1338                                 route_hints, nodes[1].keys_manager, nodes[1].keys_manager, nodes[1].logger,
1339                                 Currency::BitcoinTestnet, None, Duration::from_secs(genesis_timestamp)
1340                         ).unwrap();
1341                 let (payment_hash, payment_secret) = (PaymentHash(invoice.payment_hash().to_byte_array()), *invoice.payment_secret());
1342                 let payment_preimage = if user_generated_pmt_hash {
1343                         user_payment_preimage
1344                 } else {
1345                         nodes[1].node.get_payment_preimage(payment_hash, payment_secret).unwrap()
1346                 };
1347
1348                 assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
1349                 assert_eq!(invoice.description(), Bolt11InvoiceDescription::Direct(&Description(UntrustedString("test".to_string()))));
1350                 assert_eq!(invoice.route_hints().len(), 2);
1351                 assert_eq!(invoice.expiry_time(), Duration::from_secs(non_default_invoice_expiry_secs.into()));
1352                 assert!(!invoice.features().unwrap().supports_basic_mpp());
1353
1354                 let payment_params = PaymentParameters::from_node_id(invoice.recover_payee_pub_key(),
1355                                 invoice.min_final_cltv_expiry_delta() as u32)
1356                         .with_bolt11_features(invoice.features().unwrap().clone()).unwrap()
1357                         .with_route_hints(invoice.route_hints()).unwrap();
1358                 let params = RouteParameters::from_payment_params_and_value(
1359                         payment_params, invoice.amount_milli_satoshis().unwrap());
1360                 let (payment_event, fwd_idx) = {
1361                         let payment_hash = PaymentHash(invoice.payment_hash().to_byte_array());
1362                         nodes[0].node.send_payment(payment_hash,
1363                                 RecipientOnionFields::secret_only(*invoice.payment_secret()),
1364                                 PaymentId(payment_hash.0), params, Retry::Attempts(0)).unwrap();
1365                         let mut added_monitors = nodes[0].chain_monitor.added_monitors.lock().unwrap();
1366                         assert_eq!(added_monitors.len(), 1);
1367                         added_monitors.clear();
1368
1369                         let mut events = nodes[0].node.get_and_clear_pending_msg_events();
1370                         assert_eq!(events.len(), 1);
1371                         let fwd_idx = match events[0] {
1372                                 MessageSendEvent::UpdateHTLCs { node_id, .. } => {
1373                                         if node_id == nodes[1].node.get_our_node_id() {
1374                                                 1
1375                                         } else { 2 }
1376                                 },
1377                                 _ => panic!("Unexpected event")
1378                         };
1379                         (SendEvent::from_event(events.remove(0)), fwd_idx)
1380                 };
1381                 nodes[fwd_idx].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
1382                 commitment_signed_dance!(nodes[fwd_idx], nodes[0], &payment_event.commitment_msg, false, true);
1383
1384                 // Note that we have to "forward pending HTLCs" twice before we see the PaymentClaimable as
1385                 // this "emulates" the payment taking two hops, providing some privacy to make phantom node
1386                 // payments "look real" by taking more time.
1387                 let other_events = RefCell::new(Vec::new());
1388                 let forward_event_handler = |event: Event| {
1389                         if let Event::PendingHTLCsForwardable { .. } = event {
1390                                 nodes[fwd_idx].node.process_pending_htlc_forwards();
1391                         } else {
1392                                 other_events.borrow_mut().push(event);
1393                         }
1394                 };
1395                 nodes[fwd_idx].node.process_pending_events(&forward_event_handler);
1396                 nodes[fwd_idx].node.process_pending_events(&forward_event_handler);
1397
1398                 let payment_preimage_opt = if user_generated_pmt_hash { None } else { Some(payment_preimage) };
1399                 assert_eq!(other_events.borrow().len(), 1);
1400                 check_payment_claimable(&other_events.borrow()[0], payment_hash, payment_secret, payment_amt, payment_preimage_opt, invoice.recover_payee_pub_key());
1401                 do_claim_payment_along_route(
1402                         ClaimAlongRouteArgs::new(&nodes[0], &[&[&nodes[fwd_idx]]], payment_preimage)
1403                 );
1404                 expect_payment_sent(&nodes[0], payment_preimage, None, true, true);
1405         }
1406
1407         #[test]
1408         #[cfg(feature = "std")]
1409         fn test_multi_node_hints_has_htlc_min_max_values() {
1410                 let mut chanmon_cfgs = create_chanmon_cfgs(3);
1411                 let seed_1 = [42u8; 32];
1412                 let seed_2 = [43u8; 32];
1413                 let cross_node_seed = [44u8; 32];
1414                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1415                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1416                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1417                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1418                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1419
1420                 create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001);
1421                 create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1422
1423                 let payment_amt = 20_000;
1424                 let (payment_hash, _payment_secret) = nodes[1].node.create_inbound_payment(Some(payment_amt), 3600, None).unwrap();
1425                 let route_hints = vec![
1426                         nodes[1].node.get_phantom_route_hints(),
1427                         nodes[2].node.get_phantom_route_hints(),
1428                 ];
1429
1430                 let invoice = crate::utils::create_phantom_invoice::<&test_utils::TestKeysInterface,
1431                         &test_utils::TestKeysInterface, &test_utils::TestLogger>(Some(payment_amt), Some(payment_hash),
1432                                 "test".to_string(), 3600, route_hints, nodes[1].keys_manager, nodes[1].keys_manager,
1433                                 nodes[1].logger, Currency::BitcoinTestnet, None, Duration::from_secs(1234567)).unwrap();
1434
1435                 let chan_0_1 = &nodes[1].node.list_usable_channels()[0];
1436                 assert_eq!(invoice.route_hints()[0].0[0].htlc_minimum_msat, chan_0_1.inbound_htlc_minimum_msat);
1437                 assert_eq!(invoice.route_hints()[0].0[0].htlc_maximum_msat, chan_0_1.inbound_htlc_maximum_msat);
1438
1439                 let chan_0_2 = &nodes[2].node.list_usable_channels()[0];
1440                 assert_eq!(invoice.route_hints()[1].0[0].htlc_minimum_msat, chan_0_2.inbound_htlc_minimum_msat);
1441                 assert_eq!(invoice.route_hints()[1].0[0].htlc_maximum_msat, chan_0_2.inbound_htlc_maximum_msat);
1442         }
1443
1444         #[test]
1445         #[cfg(feature = "std")]
1446         fn create_phantom_invoice_with_description_hash() {
1447                 let chanmon_cfgs = create_chanmon_cfgs(3);
1448                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1449                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1450                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1451
1452                 let payment_amt = 20_000;
1453                 let route_hints = vec![
1454                         nodes[1].node.get_phantom_route_hints(),
1455                         nodes[2].node.get_phantom_route_hints(),
1456                 ];
1457
1458                 let description_hash = crate::Sha256(Hash::hash("Description hash phantom invoice".as_bytes()));
1459                 let non_default_invoice_expiry_secs = 4200;
1460                 let invoice = crate::utils::create_phantom_invoice_with_description_hash::<
1461                         &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestLogger,
1462                 >(
1463                         Some(payment_amt), None, non_default_invoice_expiry_secs, description_hash,
1464                         route_hints, nodes[1].keys_manager, nodes[1].keys_manager, nodes[1].logger,
1465                         Currency::BitcoinTestnet, None, Duration::from_secs(1234567),
1466                 )
1467                 .unwrap();
1468                 assert_eq!(invoice.amount_pico_btc(), Some(200_000));
1469                 assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
1470                 assert_eq!(invoice.expiry_time(), Duration::from_secs(non_default_invoice_expiry_secs.into()));
1471                 assert_eq!(invoice.description(), Bolt11InvoiceDescription::Hash(&crate::Sha256(Sha256::hash("Description hash phantom invoice".as_bytes()))));
1472         }
1473
1474         #[test]
1475         #[cfg(feature = "std")]
1476         fn create_phantom_invoice_with_custom_payment_hash_and_custom_min_final_cltv_delta() {
1477                 let chanmon_cfgs = create_chanmon_cfgs(3);
1478                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1479                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1480                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1481
1482                 let payment_amt = 20_000;
1483                 let route_hints = vec![
1484                         nodes[1].node.get_phantom_route_hints(),
1485                         nodes[2].node.get_phantom_route_hints(),
1486                 ];
1487                 let user_payment_preimage = PaymentPreimage([1; 32]);
1488                 let payment_hash = Some(PaymentHash(Sha256::hash(&user_payment_preimage.0[..]).to_byte_array()));
1489                 let non_default_invoice_expiry_secs = 4200;
1490                 let min_final_cltv_expiry_delta = Some(100);
1491                 let duration_since_epoch = Duration::from_secs(1234567);
1492                 let invoice = crate::utils::create_phantom_invoice::<&test_utils::TestKeysInterface,
1493                         &test_utils::TestKeysInterface, &test_utils::TestLogger>(Some(payment_amt), payment_hash,
1494                                 "".to_string(), non_default_invoice_expiry_secs, route_hints, nodes[1].keys_manager, nodes[1].keys_manager,
1495                                 nodes[1].logger, Currency::BitcoinTestnet, min_final_cltv_expiry_delta, duration_since_epoch).unwrap();
1496                 assert_eq!(invoice.amount_pico_btc(), Some(200_000));
1497                 assert_eq!(invoice.min_final_cltv_expiry_delta(), (min_final_cltv_expiry_delta.unwrap() + 3) as u64);
1498                 assert_eq!(invoice.expiry_time(), Duration::from_secs(non_default_invoice_expiry_secs.into()));
1499         }
1500
1501         #[test]
1502         #[cfg(feature = "std")]
1503         fn test_multi_node_hints_includes_single_channels_to_participating_nodes() {
1504                 let mut chanmon_cfgs = create_chanmon_cfgs(3);
1505                 let seed_1 = [42u8; 32];
1506                 let seed_2 = [43u8; 32];
1507                 let cross_node_seed = [44u8; 32];
1508                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1509                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1510                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1511                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1512                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1513
1514                 let chan_0_1 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001);
1515                 let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1516
1517                 let mut scid_aliases = HashSet::new();
1518                 scid_aliases.insert(chan_0_1.0.short_channel_id_alias.unwrap());
1519                 scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1520
1521                 match_multi_node_invoice_routes(
1522                         Some(10_000),
1523                         &nodes[1],
1524                         vec![&nodes[1], &nodes[2],],
1525                         scid_aliases,
1526                         false
1527                 );
1528         }
1529
1530         #[test]
1531         #[cfg(feature = "std")]
1532         fn test_multi_node_hints_includes_one_channel_of_each_counterparty_nodes_per_participating_node() {
1533                 let mut chanmon_cfgs = create_chanmon_cfgs(4);
1534                 let seed_1 = [42u8; 32];
1535                 let seed_2 = [43u8; 32];
1536                 let cross_node_seed = [44u8; 32];
1537                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1538                 chanmon_cfgs[3].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1539                 let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
1540                 let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
1541                 let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
1542
1543                 let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1544                 let chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 1000000, 10001);
1545                 let chan_1_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 3, 3_000_000, 10005);
1546
1547                 let mut scid_aliases = HashSet::new();
1548                 scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1549                 scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1550                 scid_aliases.insert(chan_1_3.0.short_channel_id_alias.unwrap());
1551
1552                 match_multi_node_invoice_routes(
1553                         Some(10_000),
1554                         &nodes[2],
1555                         vec![&nodes[2], &nodes[3],],
1556                         scid_aliases,
1557                         false
1558                 );
1559         }
1560
1561         #[test]
1562         #[cfg(feature = "std")]
1563         fn test_multi_node_forwarding_info_not_assigned_channel_excluded_from_hints() {
1564                 let mut chanmon_cfgs = create_chanmon_cfgs(4);
1565                 let seed_1 = [42u8; 32];
1566                 let seed_2 = [43u8; 32];
1567                 let cross_node_seed = [44u8; 32];
1568                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1569                 chanmon_cfgs[3].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1570                 let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
1571                 let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
1572                 let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
1573
1574                 let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1575                 let chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 1000000, 10001);
1576
1577                 // Create an unannonced channel between `nodes[1]` and `nodes[3]`, for which the
1578                 // `msgs::ChannelUpdate` is never handled for the node(s). As the `msgs::ChannelUpdate`
1579                 // is never handled, the `channel.counterparty.forwarding_info` is never assigned.
1580                 let mut private_chan_cfg = UserConfig::default();
1581                 private_chan_cfg.channel_handshake_config.announced_channel = false;
1582                 let temporary_channel_id = nodes[1].node.create_channel(nodes[3].node.get_our_node_id(), 1_000_000, 500_000_000, 42, None, Some(private_chan_cfg)).unwrap();
1583                 let open_channel = get_event_msg!(nodes[1], MessageSendEvent::SendOpenChannel, nodes[3].node.get_our_node_id());
1584                 nodes[3].node.handle_open_channel(&nodes[1].node.get_our_node_id(), &open_channel);
1585                 let accept_channel = get_event_msg!(nodes[3], MessageSendEvent::SendAcceptChannel, nodes[1].node.get_our_node_id());
1586                 nodes[1].node.handle_accept_channel(&nodes[3].node.get_our_node_id(), &accept_channel);
1587
1588                 let tx = sign_funding_transaction(&nodes[1], &nodes[3], 1_000_000, temporary_channel_id);
1589
1590                 let conf_height = core::cmp::max(nodes[1].best_block_info().1 + 1, nodes[3].best_block_info().1 + 1);
1591                 confirm_transaction_at(&nodes[1], &tx, conf_height);
1592                 connect_blocks(&nodes[1], CHAN_CONFIRM_DEPTH - 1);
1593                 confirm_transaction_at(&nodes[3], &tx, conf_height);
1594                 connect_blocks(&nodes[3], CHAN_CONFIRM_DEPTH - 1);
1595                 let as_channel_ready = get_event_msg!(nodes[1], MessageSendEvent::SendChannelReady, nodes[3].node.get_our_node_id());
1596                 nodes[1].node.handle_channel_ready(&nodes[3].node.get_our_node_id(), &get_event_msg!(nodes[3], MessageSendEvent::SendChannelReady, nodes[1].node.get_our_node_id()));
1597                 get_event_msg!(nodes[1], MessageSendEvent::SendChannelUpdate, nodes[3].node.get_our_node_id());
1598                 nodes[3].node.handle_channel_ready(&nodes[1].node.get_our_node_id(), &as_channel_ready);
1599                 get_event_msg!(nodes[3], MessageSendEvent::SendChannelUpdate, nodes[1].node.get_our_node_id());
1600                 expect_channel_ready_event(&nodes[1], &nodes[3].node.get_our_node_id());
1601                 expect_channel_ready_event(&nodes[3], &nodes[1].node.get_our_node_id());
1602
1603                 // As `msgs::ChannelUpdate` was never handled for the participating node(s) of the third
1604                 // channel, the channel will never be assigned any `counterparty.forwarding_info`.
1605                 // Therefore only `chan_0_3` should be included in the hints for `nodes[3]`.
1606                 let mut scid_aliases = HashSet::new();
1607                 scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1608                 scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1609
1610                 match_multi_node_invoice_routes(
1611                         Some(10_000),
1612                         &nodes[2],
1613                         vec![&nodes[2], &nodes[3],],
1614                         scid_aliases,
1615                         false
1616                 );
1617         }
1618
1619         #[test]
1620         #[cfg(feature = "std")]
1621         fn test_multi_node_with_only_public_channels_hints_includes_only_phantom_route() {
1622                 let mut chanmon_cfgs = create_chanmon_cfgs(3);
1623                 let seed_1 = [42u8; 32];
1624                 let seed_2 = [43u8; 32];
1625                 let cross_node_seed = [44u8; 32];
1626                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1627                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1628                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1629                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1630                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1631
1632                 let chan_0_1 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001);
1633
1634                 let chan_2_0 = create_announced_chan_between_nodes_with_value(&nodes, 2, 0, 100000, 10001);
1635                 nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_2_0.1);
1636                 nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_2_0.0);
1637
1638                 // Hints should include `chan_0_1` from as `nodes[1]` only have private channels, but not
1639                 // `chan_0_2` as `nodes[2]` only has public channels.
1640                 let mut scid_aliases = HashSet::new();
1641                 scid_aliases.insert(chan_0_1.0.short_channel_id_alias.unwrap());
1642
1643                 match_multi_node_invoice_routes(
1644                         Some(10_000),
1645                         &nodes[1],
1646                         vec![&nodes[1], &nodes[2],],
1647                         scid_aliases,
1648                         true
1649                 );
1650         }
1651
1652         #[test]
1653         #[cfg(feature = "std")]
1654         fn test_multi_node_with_mixed_public_and_private_channel_hints_includes_only_phantom_route() {
1655                 let mut chanmon_cfgs = create_chanmon_cfgs(4);
1656                 let seed_1 = [42u8; 32];
1657                 let seed_2 = [43u8; 32];
1658                 let cross_node_seed = [44u8; 32];
1659                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1660                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1661                 let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
1662                 let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
1663                 let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
1664
1665                 let chan_0_2 = create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1666                 nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_0_2.1);
1667                 nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_2.0);
1668                 let _chan_1_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 2, 100000, 10001);
1669
1670                 let chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 100000, 10001);
1671
1672                 // Hints should include `chan_0_3` from as `nodes[3]` only have private channels, and no
1673                 // channels for `nodes[2]` as it contains a mix of public and private channels.
1674                 let mut scid_aliases = HashSet::new();
1675                 scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1676
1677                 match_multi_node_invoice_routes(
1678                         Some(10_000),
1679                         &nodes[2],
1680                         vec![&nodes[2], &nodes[3],],
1681                         scid_aliases,
1682                         true
1683                 );
1684         }
1685
1686         #[test]
1687         #[cfg(feature = "std")]
1688         fn test_multi_node_hints_has_only_lowest_inbound_channel_above_minimum() {
1689                 let mut chanmon_cfgs = create_chanmon_cfgs(3);
1690                 let seed_1 = [42u8; 32];
1691                 let seed_2 = [43u8; 32];
1692                 let cross_node_seed = [44u8; 32];
1693                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1694                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1695                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1696                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1697                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1698
1699                 let _chan_0_1_below_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100_000, 0);
1700                 let _chan_0_1_above_amt_high_inbound = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 500_000, 0);
1701                 let chan_0_1_above_amt_low_inbound = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 180_000, 0);
1702                 let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
1703
1704                 let mut scid_aliases = HashSet::new();
1705                 scid_aliases.insert(chan_0_1_above_amt_low_inbound.0.short_channel_id_alias.unwrap());
1706                 scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1707
1708                 match_multi_node_invoice_routes(
1709                         Some(100_000_000),
1710                         &nodes[1],
1711                         vec![&nodes[1], &nodes[2],],
1712                         scid_aliases,
1713                         false
1714                 );
1715         }
1716
1717         #[test]
1718         #[cfg(feature = "std")]
1719         fn test_multi_node_channels_inbound_capacity_lower_than_invoice_amt_filtering() {
1720                 let mut chanmon_cfgs = create_chanmon_cfgs(4);
1721                 let seed_1 = [42u8; 32];
1722                 let seed_2 = [43u8; 32];
1723                 let cross_node_seed = [44u8; 32];
1724                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1725                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1726                 let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
1727                 let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
1728                 let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
1729
1730                 let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 1_000_000, 0);
1731                 let chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 100_000, 0);
1732                 let chan_1_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 3, 200_000, 0);
1733
1734                 // Since the invoice 1 msat above chan_0_3's inbound capacity, it should be filtered out.
1735                 let mut scid_aliases_99_000_001_msat = HashSet::new();
1736                 scid_aliases_99_000_001_msat.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1737                 scid_aliases_99_000_001_msat.insert(chan_1_3.0.short_channel_id_alias.unwrap());
1738
1739                 match_multi_node_invoice_routes(
1740                         Some(99_000_001),
1741                         &nodes[2],
1742                         vec![&nodes[2], &nodes[3],],
1743                         scid_aliases_99_000_001_msat,
1744                         false
1745                 );
1746
1747                 // Since the invoice is exactly at chan_0_3's inbound capacity, it should be included.
1748                 let mut scid_aliases_99_000_000_msat = HashSet::new();
1749                 scid_aliases_99_000_000_msat.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1750                 scid_aliases_99_000_000_msat.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1751                 scid_aliases_99_000_000_msat.insert(chan_1_3.0.short_channel_id_alias.unwrap());
1752
1753                 match_multi_node_invoice_routes(
1754                         Some(99_000_000),
1755                         &nodes[2],
1756                         vec![&nodes[2], &nodes[3],],
1757                         scid_aliases_99_000_000_msat,
1758                         false
1759                 );
1760
1761                 // Since the invoice is above all of `nodes[2]` channels' inbound capacity, all of
1762                 // `nodes[2]` them should be included.
1763                 let mut scid_aliases_300_000_000_msat = HashSet::new();
1764                 scid_aliases_300_000_000_msat.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1765                 scid_aliases_300_000_000_msat.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1766                 scid_aliases_300_000_000_msat.insert(chan_1_3.0.short_channel_id_alias.unwrap());
1767
1768                 match_multi_node_invoice_routes(
1769                         Some(300_000_000),
1770                         &nodes[2],
1771                         vec![&nodes[2], &nodes[3],],
1772                         scid_aliases_300_000_000_msat,
1773                         false
1774                 );
1775
1776                 // Since the no specified amount, all channels should included.
1777                 let mut scid_aliases_no_specified_amount = HashSet::new();
1778                 scid_aliases_no_specified_amount.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1779                 scid_aliases_no_specified_amount.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1780                 scid_aliases_no_specified_amount.insert(chan_1_3.0.short_channel_id_alias.unwrap());
1781
1782                 match_multi_node_invoice_routes(
1783                         None,
1784                         &nodes[2],
1785                         vec![&nodes[2], &nodes[3],],
1786                         scid_aliases_no_specified_amount,
1787                         false
1788                 );
1789         }
1790
1791         #[test]
1792         fn test_multi_node_hints_limited_to_3() {
1793                 let mut chanmon_cfgs = create_chanmon_cfgs(6);
1794                 let seed_1 = [42 as u8; 32];
1795                 let seed_2 = [43 as u8; 32];
1796                 let seed_3 = [44 as u8; 32];
1797                 let seed_4 = [45 as u8; 32];
1798                 let cross_node_seed = [44 as u8; 32];
1799                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1800                 chanmon_cfgs[3].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1801                 chanmon_cfgs[4].keys_manager.backing = PhantomKeysManager::new(&seed_3, 43, 44, &cross_node_seed);
1802                 chanmon_cfgs[5].keys_manager.backing = PhantomKeysManager::new(&seed_4, 43, 44, &cross_node_seed);
1803                 let node_cfgs = create_node_cfgs(6, &chanmon_cfgs);
1804                 let node_chanmgrs = create_node_chanmgrs(6, &node_cfgs, &[None, None, None, None, None, None]);
1805                 let nodes = create_network(6, &node_cfgs, &node_chanmgrs);
1806
1807                 // Setup each phantom node with two channels from distinct peers.
1808                 let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 10_000, 0);
1809                 let chan_1_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 2, 20_000, 0);
1810                 let chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 20_000, 0);
1811                 let _chan_1_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 3, 10_000, 0);
1812                 let chan_0_4 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 4, 20_000, 0);
1813                 let _chan_1_4 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000, 0);
1814                 let _chan_0_5 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 5, 20_000, 0);
1815                 let _chan_1_5 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000, 0);
1816
1817                 // Set invoice amount > all channels inbound so that every one is eligible for inclusion
1818                 // and hints will be sorted by largest inbound capacity.
1819                 let invoice_amt = Some(100_000_000);
1820
1821                 // With 4 phantom nodes, assert that we include 1 hint per node, up to 3 nodes.
1822                 let mut scid_aliases = HashSet::new();
1823                 scid_aliases.insert(chan_1_2.0.short_channel_id_alias.unwrap());
1824                 scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1825                 scid_aliases.insert(chan_0_4.0.short_channel_id_alias.unwrap());
1826
1827                 match_multi_node_invoice_routes(
1828                         invoice_amt,
1829                         &nodes[3],
1830                         vec![&nodes[2], &nodes[3], &nodes[4], &nodes[5]],
1831                         scid_aliases,
1832                         false,
1833                 );
1834
1835                 // With 2 phantom nodes, assert that we include no more than 3 hints.
1836                 let mut scid_aliases = HashSet::new();
1837                 scid_aliases.insert(chan_1_2.0.short_channel_id_alias.unwrap());
1838                 scid_aliases.insert(chan_0_3.0.short_channel_id_alias.unwrap());
1839                 scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap());
1840
1841                 match_multi_node_invoice_routes(
1842                         invoice_amt,
1843                         &nodes[3],
1844                         vec![&nodes[2], &nodes[3]],
1845                         scid_aliases,
1846                         false,
1847                 );
1848         }
1849
1850         #[test]
1851         fn test_multi_node_hints_at_least_3() {
1852                 let mut chanmon_cfgs = create_chanmon_cfgs(5);
1853                 let seed_1 = [42 as u8; 32];
1854                 let seed_2 = [43 as u8; 32];
1855                 let cross_node_seed = [44 as u8; 32];
1856                 chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
1857                 chanmon_cfgs[2].keys_manager.backing = PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
1858                 let node_cfgs = create_node_cfgs(5, &chanmon_cfgs);
1859                 let node_chanmgrs = create_node_chanmgrs(5, &node_cfgs, &[None, None, None, None, None]);
1860                 let nodes = create_network(5, &node_cfgs, &node_chanmgrs);
1861
1862                 let _chan_0_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 3, 10_000, 0);
1863                 let chan_1_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 3, 20_000, 0);
1864                 let chan_2_3 = create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 30_000, 0);
1865                 let chan_0_4 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000, 0);
1866
1867                 // Since the invoice amount is above all channels inbound, all four are eligible. Test that
1868                 // we still include 3 hints from 2 distinct nodes sorted by inbound.
1869                 let mut scid_aliases = HashSet::new();
1870                 scid_aliases.insert(chan_1_3.0.short_channel_id_alias.unwrap());
1871                 scid_aliases.insert(chan_2_3.0.short_channel_id_alias.unwrap());
1872                 scid_aliases.insert(chan_0_4.0.short_channel_id_alias.unwrap());
1873
1874                 match_multi_node_invoice_routes(
1875                         Some(100_000_000),
1876                         &nodes[3],
1877                         vec![&nodes[3], &nodes[4],],
1878                         scid_aliases,
1879                         false,
1880                 );
1881         }
1882
1883         fn match_multi_node_invoice_routes<'a, 'b: 'a, 'c: 'b>(
1884                 invoice_amt: Option<u64>,
1885                 invoice_node: &Node<'a, 'b, 'c>,
1886                 network_multi_nodes: Vec<&Node<'a, 'b, 'c>>,
1887                 mut chan_ids_to_match: HashSet<u64>,
1888                 nodes_contains_public_channels: bool
1889         ){
1890                 let phantom_route_hints = network_multi_nodes.iter()
1891                         .map(|node| node.node.get_phantom_route_hints())
1892                         .collect::<Vec<PhantomRouteHints>>();
1893                 let phantom_scids = phantom_route_hints.iter()
1894                         .map(|route_hint| route_hint.phantom_scid)
1895                         .collect::<HashSet<u64>>();
1896
1897                 let invoice = crate::utils::create_phantom_invoice::<&test_utils::TestKeysInterface,
1898                         &test_utils::TestKeysInterface, &test_utils::TestLogger>(invoice_amt, None, "test".to_string(),
1899                                 3600, phantom_route_hints, invoice_node.keys_manager, invoice_node.keys_manager,
1900                                 invoice_node.logger, Currency::BitcoinTestnet, None, Duration::from_secs(1234567)).unwrap();
1901
1902                 let invoice_hints = invoice.private_routes();
1903
1904                 for hint in invoice_hints {
1905                         let hints = &(hint.0).0;
1906                         match hints.len() {
1907                                 1 => {
1908                                         assert!(nodes_contains_public_channels);
1909                                         let phantom_scid = hints[0].short_channel_id;
1910                                         assert!(phantom_scids.contains(&phantom_scid));
1911                                 },
1912                                 2 => {
1913                                         let hint_short_chan_id = hints[0].short_channel_id;
1914                                         assert!(chan_ids_to_match.remove(&hint_short_chan_id));
1915                                         let phantom_scid = hints[1].short_channel_id;
1916                                         assert!(phantom_scids.contains(&phantom_scid));
1917                                 },
1918                                 _ => panic!("Incorrect hint length generated")
1919                         }
1920                 }
1921                 assert!(chan_ids_to_match.is_empty(), "Unmatched short channel ids: {:?}", chan_ids_to_match);
1922         }
1923
1924         #[test]
1925         fn test_create_invoice_fails_with_invalid_custom_min_final_cltv_expiry_delta() {
1926                 let chanmon_cfgs = create_chanmon_cfgs(2);
1927                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1928                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
1929                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1930                 let result = crate::utils::create_invoice_from_channelmanager_and_duration_since_epoch(
1931                         nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::BitcoinTestnet,
1932                         Some(10_000), "Some description".into(), Duration::from_secs(1234567), 3600, Some(MIN_FINAL_CLTV_EXPIRY_DELTA - 4),
1933                 );
1934                 match result {
1935                         Err(SignOrCreationError::CreationError(CreationError::MinFinalCltvExpiryDeltaTooShort)) => {},
1936                         _ => panic!(),
1937                 }
1938         }
1939
1940         #[test]
1941         fn test_rotate_through_iterators() {
1942                 // two nested vectors
1943                 let a = vec![vec!["a0", "b0", "c0"].into_iter(), vec!["a1", "b1"].into_iter()];
1944                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
1945
1946                 let expected = vec!["a0", "a1", "b0", "b1", "c0"];
1947                 assert_eq!(expected, result);
1948
1949                 // test single nested vector
1950                 let a = vec![vec!["a0", "b0", "c0"].into_iter()];
1951                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
1952
1953                 let expected = vec!["a0", "b0", "c0"];
1954                 assert_eq!(expected, result);
1955
1956                 // test second vector with only one element
1957                 let a = vec![vec!["a0", "b0", "c0"].into_iter(), vec!["a1"].into_iter()];
1958                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
1959
1960                 let expected = vec!["a0", "a1", "b0", "c0"];
1961                 assert_eq!(expected, result);
1962
1963                 // test three nestend vectors
1964                 let a = vec![vec!["a0"].into_iter(), vec!["a1", "b1", "c1"].into_iter(), vec!["a2"].into_iter()];
1965                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
1966
1967                 let expected = vec!["a0", "a1", "a2", "b1", "c1"];
1968                 assert_eq!(expected, result);
1969
1970                 // test single nested vector with a single value
1971                 let a = vec![vec!["a0"].into_iter()];
1972                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
1973
1974                 let expected = vec!["a0"];
1975                 assert_eq!(expected, result);
1976
1977                 // test single empty nested vector
1978                 let a:Vec<std::vec::IntoIter<&str>> = vec![vec![].into_iter()];
1979                 let result = rotate_through_iterators(a).collect::<Vec<&str>>();
1980                 let expected:Vec<&str> = vec![];
1981
1982                 assert_eq!(expected, result);
1983
1984                 // test first nested vector is empty
1985                 let a:Vec<std::vec::IntoIter<&str>>= vec![vec![].into_iter(), vec!["a1", "b1", "c1"].into_iter()];
1986                 let result = rotate_through_iterators(a).collect::<Vec<&str>>();
1987
1988                 let expected = vec!["a1", "b1", "c1"];
1989                 assert_eq!(expected, result);
1990
1991                 // test two empty vectors
1992                 let a:Vec<std::vec::IntoIter<&str>> = vec![vec![].into_iter(), vec![].into_iter()];
1993                 let result = rotate_through_iterators(a).collect::<Vec<&str>>();
1994
1995                 let expected:Vec<&str> = vec![];
1996                 assert_eq!(expected, result);
1997
1998                 // test an empty vector amongst other filled vectors
1999                 let a = vec![
2000                         vec!["a0", "b0", "c0"].into_iter(),
2001                         vec![].into_iter(),
2002                         vec!["a1", "b1", "c1"].into_iter(),
2003                         vec!["a2", "b2", "c2"].into_iter(),
2004                 ];
2005                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
2006
2007                 let expected = vec!["a0", "a1", "a2", "b0", "b1", "b2", "c0", "c1", "c2"];
2008                 assert_eq!(expected, result);
2009
2010                 // test a filled vector between two empty vectors
2011                 let a = vec![vec![].into_iter(), vec!["a1", "b1", "c1"].into_iter(), vec![].into_iter()];
2012                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
2013
2014                 let expected = vec!["a1", "b1", "c1"];
2015                 assert_eq!(expected, result);
2016
2017                 // test an empty vector at the end of the vectors
2018                 let a = vec![vec!["a0", "b0", "c0"].into_iter(), vec![].into_iter()];
2019                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
2020
2021                 let expected = vec!["a0", "b0", "c0"];
2022                 assert_eq!(expected, result);
2023
2024                 // test multiple empty vectors amongst multiple filled vectors
2025                 let a = vec![
2026                         vec![].into_iter(),
2027                         vec!["a1", "b1", "c1"].into_iter(),
2028                         vec![].into_iter(),
2029                         vec!["a3", "b3"].into_iter(),
2030                         vec![].into_iter(),
2031                 ];
2032
2033                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
2034
2035                 let expected = vec!["a1", "a3", "b1", "b3", "c1"];
2036                 assert_eq!(expected, result);
2037
2038                 // test one element in the first nested vectore and two elements in the second nested
2039                 // vector
2040                 let a = vec![vec!["a0"].into_iter(), vec!["a1", "b1"].into_iter()];
2041                 let result = rotate_through_iterators(a).collect::<Vec<_>>();
2042
2043                 let expected = vec!["a0", "a1", "b1"];
2044                 assert_eq!(expected, result);
2045         }
2046 }