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