Merge pull request #2277 from valentinewallace/2023-05-fix-big-oms
[rust-lightning] / lightning-invoice / src / lib.rs
index defe958a1c05406cf8eb6cdfe409c9958c26458b..f53c8953b47c66b9344d86a928d9e834790989f7 100644 (file)
 //! invoices and functions to create, encode and decode these. If you just want to use the standard
 //! en-/decoding functionality this should get you started:
 //!
-//!   * For parsing use `str::parse::<Invoice>(&self)` (see the docs of `impl FromStr for Invoice`)
-//!   * For constructing invoices use the `InvoiceBuilder`
-//!   * For serializing invoices use the `Display`/`ToString` traits
+//!   * For parsing use `str::parse::<Invoice>(&self)` (see [`Invoice::from_str`])
+//!   * For constructing invoices use the [`InvoiceBuilder`]
+//!   * For serializing invoices use the [`Display`]/[`ToString`] traits
+//!
+//! [`Invoice::from_str`]: crate::Invoice#impl-FromStr
 
 #[cfg(not(any(feature = "std", feature = "no-std")))]
 compile_error!("at least one of the `std` or `no-std` features must be enabled");
@@ -45,8 +47,9 @@ extern crate serde;
 use std::time::SystemTime;
 
 use bech32::u5;
-use bitcoin_hashes::Hash;
-use bitcoin_hashes::sha256;
+use bitcoin::{Address, Network, PubkeyHash, ScriptHash};
+use bitcoin::util::address::{Payload, WitnessVersion};
+use bitcoin_hashes::{Hash, sha256};
 use lightning::ln::PaymentSecret;
 use lightning::ln::features::InvoiceFeatures;
 #[cfg(any(doc, test))]
@@ -86,7 +89,7 @@ mod prelude {
        pub use alloc::string::ToString;
 }
 
-use prelude::*;
+use crate::prelude::*;
 
 /// Sync compat for std/no_std
 #[cfg(feature = "std")]
@@ -101,7 +104,7 @@ mod sync;
 /// Errors that indicate what is wrong with the invoice. They have some granularity for debug
 /// reasons, but should generally result in an "invalid BOLT11 invoice" message for the user.
 #[allow(missing_docs)]
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum ParseError {
        Bech32Error(bech32::Error),
        ParseAmountError(ParseIntError),
@@ -129,13 +132,13 @@ pub enum ParseError {
 /// Indicates that something went wrong while parsing or validating the invoice. Parsing errors
 /// should be mostly seen as opaque and are only there for debugging reasons. Semantic errors
 /// like wrong signatures, missing fields etc. could mean that someone tampered with the invoice.
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum ParseOrSemanticError {
        /// The invoice couldn't be decoded
        ParseError(ParseError),
 
        /// The invoice could be decoded but violates the BOLT11 standard
-       SemanticError(::SemanticError),
+       SemanticError(crate::SemanticError),
 }
 
 /// The number of bits used to represent timestamps as defined in BOLT 11.
@@ -154,13 +157,13 @@ pub const DEFAULT_EXPIRY_TIME: u64 = 3600;
 /// Default minimum final CLTV expiry as defined by [BOLT 11].
 ///
 /// Note that this is *not* the same value as rust-lightning's minimum CLTV expiry, which is
-/// provided in [`MIN_FINAL_CLTV_EXPIRY`].
+/// provided in [`MIN_FINAL_CLTV_EXPIRY_DELTA`].
 ///
 /// [BOLT 11]: https://github.com/lightning/bolts/blob/master/11-payment-encoding.md
-/// [`MIN_FINAL_CLTV_EXPIRY`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY
-pub const DEFAULT_MIN_FINAL_CLTV_EXPIRY: u64 = 18;
+/// [`MIN_FINAL_CLTV_EXPIRY_DELTA`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA
+pub const DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA: u64 = 18;
 
-/// Builder for `Invoice`s. It's the most convenient and advised way to use this library. It ensures
+/// Builder for [`Invoice`]s. It's the most convenient and advised way to use this library. It ensures
 /// that only a semantically and syntactically correct Invoice can be built using it.
 ///
 /// ```
@@ -199,7 +202,7 @@ pub const DEFAULT_MIN_FINAL_CLTV_EXPIRY: u64 = 18;
 ///    .payment_hash(payment_hash)
 ///    .payment_secret(payment_secret)
 ///    .current_timestamp()
-///    .min_final_cltv_expiry(144)
+///    .min_final_cltv_expiry_delta(144)
 ///    .build_signed(|hash| {
 ///            Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)
 ///    })
@@ -212,13 +215,16 @@ pub const DEFAULT_MIN_FINAL_CLTV_EXPIRY: u64 = 18;
 /// # Type parameters
 /// The two parameters `D` and `H` signal if the builder already contains the correct amount of the
 /// given field:
-///  * `D`: exactly one `Description` or `DescriptionHash`
-///  * `H`: exactly one `PaymentHash`
+///  * `D`: exactly one [`TaggedField::Description`] or [`TaggedField::DescriptionHash`]
+///  * `H`: exactly one [`TaggedField::PaymentHash`]
 ///  * `T`: the timestamp is set
+///  * `C`: the CLTV expiry is set
+///  * `S`: the payment secret is set
+///  * `M`: payment metadata is set
 ///
-/// (C-not exported) as we likely need to manually select one set of boolean type parameters.
+/// This is not exported to bindings users as we likely need to manually select one set of boolean type parameters.
 #[derive(Eq, PartialEq, Debug, Clone)]
-pub struct InvoiceBuilder<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> {
+pub struct InvoiceBuilder<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool, M: tb::Bool> {
        currency: Currency,
        amount: Option<u64>,
        si_prefix: Option<SiPrefix>,
@@ -231,14 +237,17 @@ pub struct InvoiceBuilder<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S:
        phantom_t: core::marker::PhantomData<T>,
        phantom_c: core::marker::PhantomData<C>,
        phantom_s: core::marker::PhantomData<S>,
+       phantom_m: core::marker::PhantomData<M>,
 }
 
 /// Represents a syntactically and semantically correct lightning BOLT11 invoice.
 ///
 /// There are three ways to construct an `Invoice`:
-///  1. using `InvoiceBuilder`
-///  2. using `Invoice::from_signed(SignedRawInvoice)`
-///  3. using `str::parse::<Invoice>(&str)`
+///  1. using [`InvoiceBuilder`]
+///  2. using [`Invoice::from_signed`]
+///  3. using `str::parse::<Invoice>(&str)` (see [`Invoice::from_str`])
+///
+/// [`Invoice::from_str`]: crate::Invoice#impl-FromStr
 #[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct Invoice {
        signed_invoice: SignedRawInvoice,
@@ -247,7 +256,7 @@ pub struct Invoice {
 /// Represents the description of an invoice which has to be either a directly included string or
 /// a hash of a description provided out of band.
 ///
-/// (C-not exported) As we don't have a good way to map the reference lifetimes making this
+/// This is not exported to bindings users as we don't have a good way to map the reference lifetimes making this
 /// practically impossible to use safely in languages like C.
 #[derive(Eq, PartialEq, Debug, Clone)]
 pub enum InvoiceDescription<'f> {
@@ -258,34 +267,34 @@ pub enum InvoiceDescription<'f> {
        Hash(&'f Sha256),
 }
 
-/// Represents a signed `RawInvoice` with cached hash. The signature is not checked and may be
+/// Represents a signed [`RawInvoice`] with cached hash. The signature is not checked and may be
 /// invalid.
 ///
 /// # Invariants
-/// The hash has to be either from the deserialized invoice or from the serialized `raw_invoice`.
+/// The hash has to be either from the deserialized invoice or from the serialized [`RawInvoice`].
 #[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct SignedRawInvoice {
        /// The rawInvoice that the signature belongs to
        raw_invoice: RawInvoice,
 
-       /// Hash of the `RawInvoice` that will be used to check the signature.
+       /// Hash of the [`RawInvoice`] that will be used to check the signature.
        ///
        /// * if the `SignedRawInvoice` was deserialized the hash is of from the original encoded form,
        /// since it's not guaranteed that encoding it again will lead to the same result since integers
        /// could have been encoded with leading zeroes etc.
        /// * if the `SignedRawInvoice` was constructed manually the hash will be the calculated hash
-       /// from the `RawInvoice`
+       /// from the [`RawInvoice`]
        hash: [u8; 32],
 
        /// signature of the payment request
        signature: InvoiceSignature,
 }
 
-/// Represents an syntactically correct Invoice for a payment on the lightning network,
+/// Represents an syntactically correct [`Invoice`] for a payment on the lightning network,
 /// but without the signature information.
-/// De- and encoding should not lead to information loss but may lead to different hashes.
+/// Decoding and encoding should not lead to information loss but may lead to different hashes.
 ///
-/// For methods without docs see the corresponding methods in `Invoice`.
+/// For methods without docs see the corresponding methods in [`Invoice`].
 #[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct RawInvoice {
        /// human readable part
@@ -295,9 +304,9 @@ pub struct RawInvoice {
        pub data: RawDataPart,
 }
 
-/// Data of the `RawInvoice` that is encoded in the human readable part
+/// Data of the [`RawInvoice`] that is encoded in the human readable part.
 ///
-/// (C-not exported) As we don't yet support Option<Enum>
+/// This is not exported to bindings users as we don't yet support `Option<Enum>`
 #[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct RawHrp {
        /// The currency deferred from the 3rd and 4th character of the bech32 transaction
@@ -310,7 +319,7 @@ pub struct RawHrp {
        pub si_prefix: Option<SiPrefix>,
 }
 
-/// Data of the `RawInvoice` that is encoded in the data part
+/// Data of the [`RawInvoice`] that is encoded in the data part
 #[derive(Eq, PartialEq, Debug, Clone, Hash)]
 pub struct RawDataPart {
        /// generation time of the invoice
@@ -357,10 +366,10 @@ impl SiPrefix {
        /// Returns all enum variants of `SiPrefix` sorted in descending order of their associated
        /// multiplier.
        ///
-       /// (C-not exported) As we don't yet support a slice of enums, and also because this function
+       /// This is not exported to bindings users as we don't yet support a slice of enums, and also because this function
        /// isn't the most critical to expose.
        pub fn values_desc() -> &'static [SiPrefix] {
-               use SiPrefix::*;
+               use crate::SiPrefix::*;
                static VALUES: [SiPrefix; 4] = [Milli, Micro, Nano, Pico];
                &VALUES
        }
@@ -385,9 +394,32 @@ pub enum Currency {
        Signet,
 }
 
+impl From<Network> for Currency {
+       fn from(network: Network) -> Self {
+               match network {
+                       Network::Bitcoin => Currency::Bitcoin,
+                       Network::Testnet => Currency::BitcoinTestnet,
+                       Network::Regtest => Currency::Regtest,
+                       Network::Signet => Currency::Signet,
+               }
+       }
+}
+
+impl From<Currency> for Network {
+       fn from(currency: Currency) -> Self {
+               match currency {
+                       Currency::Bitcoin => Network::Bitcoin,
+                       Currency::BitcoinTestnet => Network::Testnet,
+                       Currency::Regtest => Network::Regtest,
+                       Currency::Simnet => Network::Regtest,
+                       Currency::Signet => Network::Signet,
+               }
+       }
+}
+
 /// Tagged field which may have an unknown tag
 ///
-/// (C-not exported) as we don't currently support TaggedField
+/// This is not exported to bindings users as we don't currently support TaggedField
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
 pub enum RawTaggedField {
        /// Parsed tagged field with known tag
@@ -400,7 +432,7 @@ pub enum RawTaggedField {
 ///
 /// For descriptions of the enum values please refer to the enclosed type's docs.
 ///
-/// (C-not exported) As we don't yet support enum variants with the same name the struct contained
+/// This is not exported to bindings users as we don't yet support enum variants with the same name the struct contained
 /// in the variant.
 #[allow(missing_docs)]
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
@@ -410,18 +442,28 @@ pub enum TaggedField {
        PayeePubKey(PayeePubKey),
        DescriptionHash(Sha256),
        ExpiryTime(ExpiryTime),
-       MinFinalCltvExpiry(MinFinalCltvExpiry),
+       MinFinalCltvExpiryDelta(MinFinalCltvExpiryDelta),
        Fallback(Fallback),
        PrivateRoute(PrivateRoute),
        PaymentSecret(PaymentSecret),
+       PaymentMetadata(Vec<u8>),
        Features(InvoiceFeatures),
 }
 
 /// SHA-256 hash
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
-pub struct Sha256(/// (C-not exported) as the native hash types are not currently mapped
+pub struct Sha256(/// This is not exported to bindings users as the native hash types are not currently mapped
        pub sha256::Hash);
 
+impl Sha256 {
+       /// Constructs a new [`Sha256`] from the given bytes, which are assumed to be the output of a
+       /// single sha256 hash.
+       #[cfg(c_bindings)]
+       pub fn from_bytes(bytes: &[u8; 32]) -> Self {
+               Self(sha256::Hash::from_slice(bytes).expect("from_slice only fails if len is not 32"))
+       }
+}
+
 /// Description string
 ///
 /// # Invariants
@@ -438,21 +480,20 @@ pub struct PayeePubKey(pub PublicKey);
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
 pub struct ExpiryTime(Duration);
 
-/// `min_final_cltv_expiry` to use for the last HTLC in the route
+/// `min_final_cltv_expiry_delta` to use for the last HTLC in the route
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
-pub struct MinFinalCltvExpiry(pub u64);
+pub struct MinFinalCltvExpiryDelta(pub u64);
 
-// TODO: better types instead onf byte arrays
 /// Fallback address in case no LN payment is possible
 #[allow(missing_docs)]
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
 pub enum Fallback {
        SegWitProgram {
-               version: u5,
+               version: WitnessVersion,
                program: Vec<u8>,
        },
-       PubKeyHash([u8; 20]),
-       ScriptHash([u8; 20]),
+       PubKeyHash(PubkeyHash),
+       ScriptHash(ScriptHash),
 }
 
 /// Recoverable signature
@@ -475,19 +516,20 @@ pub mod constants {
        pub const TAG_PAYEE_PUB_KEY: u8 = 19;
        pub const TAG_DESCRIPTION_HASH: u8 = 23;
        pub const TAG_EXPIRY_TIME: u8 = 6;
-       pub const TAG_MIN_FINAL_CLTV_EXPIRY: u8 = 24;
+       pub const TAG_MIN_FINAL_CLTV_EXPIRY_DELTA: u8 = 24;
        pub const TAG_FALLBACK: u8 = 9;
        pub const TAG_PRIVATE_ROUTE: u8 = 3;
        pub const TAG_PAYMENT_SECRET: u8 = 16;
+       pub const TAG_PAYMENT_METADATA: u8 = 27;
        pub const TAG_FEATURES: u8 = 5;
 }
 
-impl InvoiceBuilder<tb::False, tb::False, tb::False, tb::False, tb::False> {
+impl InvoiceBuilder<tb::False, tb::False, tb::False, tb::False, tb::False, tb::False> {
        /// Construct new, empty `InvoiceBuilder`. All necessary fields have to be filled first before
        /// `InvoiceBuilder::build(self)` becomes available.
-       pub fn new(currrency: Currency) -> Self {
+       pub fn new(currency: Currency) -> Self {
                InvoiceBuilder {
-                       currency: currrency,
+                       currency,
                        amount: None,
                        si_prefix: None,
                        timestamp: None,
@@ -499,14 +541,15 @@ impl InvoiceBuilder<tb::False, tb::False, tb::False, tb::False, tb::False> {
                        phantom_t: core::marker::PhantomData,
                        phantom_c: core::marker::PhantomData,
                        phantom_s: core::marker::PhantomData,
+                       phantom_m: core::marker::PhantomData,
                }
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, C, S> {
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool, M: tb::Bool> InvoiceBuilder<D, H, T, C, S, M> {
        /// Helper function to set the completeness flags.
-       fn set_flags<DN: tb::Bool, HN: tb::Bool, TN: tb::Bool, CN: tb::Bool, SN: tb::Bool>(self) -> InvoiceBuilder<DN, HN, TN, CN, SN> {
-               InvoiceBuilder::<DN, HN, TN, CN, SN> {
+       fn set_flags<DN: tb::Bool, HN: tb::Bool, TN: tb::Bool, CN: tb::Bool, SN: tb::Bool, MN: tb::Bool>(self) -> InvoiceBuilder<DN, HN, TN, CN, SN, MN> {
+               InvoiceBuilder::<DN, HN, TN, CN, SN, MN> {
                        currency: self.currency,
                        amount: self.amount,
                        si_prefix: self.si_prefix,
@@ -519,6 +562,7 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBui
                        phantom_t: core::marker::PhantomData,
                        phantom_c: core::marker::PhantomData,
                        phantom_s: core::marker::PhantomData,
+                       phantom_m: core::marker::PhantomData,
                }
        }
 
@@ -540,7 +584,8 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBui
                self
        }
 
-       /// Sets the expiry time
+       /// Sets the expiry time, dropping the subsecond part (which is not representable in BOLT 11
+       /// invoices).
        pub fn expiry_time(mut self, expiry_time: Duration) -> Self {
                self.tagged_fields.push(TaggedField::ExpiryTime(ExpiryTime::from_duration(expiry_time)));
                self
@@ -562,8 +607,9 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBui
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb::True, C, S> {
-       /// Builds a `RawInvoice` if no `CreationError` occurred while construction any of the fields.
+impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool, M: tb::Bool> InvoiceBuilder<D, H, tb::True, C, S, M> {
+       /// Builds a [`RawInvoice`] if no [`CreationError`] occurred while construction any of the
+       /// fields.
        pub fn build_raw(self) -> Result<RawInvoice, CreationError> {
 
                // If an error occurred at any time before, return it now
@@ -584,20 +630,20 @@ impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb
                }).collect::<Vec<_>>();
 
                let data = RawDataPart {
-                       timestamp: timestamp,
-                       tagged_fields: tagged_fields,
+                       timestamp,
+                       tagged_fields,
                };
 
                Ok(RawInvoice {
-                       hrp: hrp,
-                       data: data,
+                       hrp,
+                       data,
                })
        }
 }
 
-impl<H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<tb::False, H, T, C, S> {
+impl<H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool, M: tb::Bool> InvoiceBuilder<tb::False, H, T, C, S, M> {
        /// Set the description. This function is only available if no description (hash) was set.
-       pub fn description(mut self, description: String) -> InvoiceBuilder<tb::True, H, T, C, S> {
+       pub fn description(mut self, description: String) -> InvoiceBuilder<tb::True, H, T, C, S, M> {
                match Description::new(description) {
                        Ok(d) => self.tagged_fields.push(TaggedField::Description(d)),
                        Err(e) => self.error = Some(e),
@@ -606,24 +652,36 @@ impl<H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<tb::Fals
        }
 
        /// Set the description hash. This function is only available if no description (hash) was set.
-       pub fn description_hash(mut self, description_hash: sha256::Hash) -> InvoiceBuilder<tb::True, H, T, C, S> {
+       pub fn description_hash(mut self, description_hash: sha256::Hash) -> InvoiceBuilder<tb::True, H, T, C, S, M> {
                self.tagged_fields.push(TaggedField::DescriptionHash(Sha256(description_hash)));
                self.set_flags()
        }
+
+       /// Set the description or description hash. This function is only available if no description (hash) was set.
+       pub fn invoice_description(self, description: InvoiceDescription) -> InvoiceBuilder<tb::True, H, T, C, S, M> {
+               match description {
+                       InvoiceDescription::Direct(desc) => {
+                               self.description(desc.clone().into_inner())
+                       }
+                       InvoiceDescription::Hash(hash) => {
+                               self.description_hash(hash.0)
+                       }
+               }
+       }
 }
 
-impl<D: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, tb::False, T, C, S> {
+impl<D: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool, M: tb::Bool> InvoiceBuilder<D, tb::False, T, C, S, M> {
        /// Set the payment hash. This function is only available if no payment hash was set.
-       pub fn payment_hash(mut self, hash: sha256::Hash) -> InvoiceBuilder<D, tb::True, T, C, S> {
+       pub fn payment_hash(mut self, hash: sha256::Hash) -> InvoiceBuilder<D, tb::True, T, C, S, M> {
                self.tagged_fields.push(TaggedField::PaymentHash(Sha256(hash)));
                self.set_flags()
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb::False, C, S> {
+impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool, M: tb::Bool> InvoiceBuilder<D, H, tb::False, C, S, M> {
        /// Sets the timestamp to a specific [`SystemTime`].
        #[cfg(feature = "std")]
-       pub fn timestamp(mut self, time: SystemTime) -> InvoiceBuilder<D, H, tb::True, C, S> {
+       pub fn timestamp(mut self, time: SystemTime) -> InvoiceBuilder<D, H, tb::True, C, S, M> {
                match PositiveTimestamp::from_system_time(time) {
                        Ok(t) => self.timestamp = Some(t),
                        Err(e) => self.error = Some(e),
@@ -632,8 +690,9 @@ impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb
                self.set_flags()
        }
 
-       /// Sets the timestamp to a duration since the Unix epoch.
-       pub fn duration_since_epoch(mut self, time: Duration) -> InvoiceBuilder<D, H, tb::True, C, S> {
+       /// Sets the timestamp to a duration since the Unix epoch, dropping the subsecond part (which
+       /// is not representable in BOLT 11 invoices).
+       pub fn duration_since_epoch(mut self, time: Duration) -> InvoiceBuilder<D, H, tb::True, C, S, M> {
                match PositiveTimestamp::from_duration_since_epoch(time) {
                        Ok(t) => self.timestamp = Some(t),
                        Err(e) => self.error = Some(e),
@@ -644,34 +703,82 @@ impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb
 
        /// Sets the timestamp to the current system time.
        #[cfg(feature = "std")]
-       pub fn current_timestamp(mut self) -> InvoiceBuilder<D, H, tb::True, C, S> {
+       pub fn current_timestamp(mut self) -> InvoiceBuilder<D, H, tb::True, C, S, M> {
                let now = PositiveTimestamp::from_system_time(SystemTime::now());
                self.timestamp = Some(now.expect("for the foreseeable future this shouldn't happen"));
                self.set_flags()
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, tb::False, S> {
-       /// Sets `min_final_cltv_expiry`.
-       pub fn min_final_cltv_expiry(mut self, min_final_cltv_expiry: u64) -> InvoiceBuilder<D, H, T, tb::True, S> {
-               self.tagged_fields.push(TaggedField::MinFinalCltvExpiry(MinFinalCltvExpiry(min_final_cltv_expiry)));
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, S: tb::Bool, M: tb::Bool> InvoiceBuilder<D, H, T, tb::False, S, M> {
+       /// Sets `min_final_cltv_expiry_delta`.
+       pub fn min_final_cltv_expiry_delta(mut self, min_final_cltv_expiry_delta: u64) -> InvoiceBuilder<D, H, T, tb::True, S, M> {
+               self.tagged_fields.push(TaggedField::MinFinalCltvExpiryDelta(MinFinalCltvExpiryDelta(min_final_cltv_expiry_delta)));
                self.set_flags()
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T, C, tb::False> {
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, M: tb::Bool> InvoiceBuilder<D, H, T, C, tb::False, M> {
        /// Sets the payment secret and relevant features.
-       pub fn payment_secret(mut self, payment_secret: PaymentSecret) -> InvoiceBuilder<D, H, T, C, tb::True> {
-               let mut features = InvoiceFeatures::empty();
-               features.set_variable_length_onion_required();
-               features.set_payment_secret_required();
+       pub fn payment_secret(mut self, payment_secret: PaymentSecret) -> InvoiceBuilder<D, H, T, C, tb::True, M> {
+               let mut found_features = false;
+               for field in self.tagged_fields.iter_mut() {
+                       if let TaggedField::Features(f) = field {
+                               found_features = true;
+                               f.set_variable_length_onion_required();
+                               f.set_payment_secret_required();
+                       }
+               }
                self.tagged_fields.push(TaggedField::PaymentSecret(payment_secret));
-               self.tagged_fields.push(TaggedField::Features(features));
+               if !found_features {
+                       let mut features = InvoiceFeatures::empty();
+                       features.set_variable_length_onion_required();
+                       features.set_payment_secret_required();
+                       self.tagged_fields.push(TaggedField::Features(features));
+               }
+               self.set_flags()
+       }
+}
+
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, C, S, tb::False> {
+       /// Sets the payment metadata.
+       ///
+       /// By default features are set to *optionally* allow the sender to include the payment metadata.
+       /// If you wish to require that the sender include the metadata (and fail to parse the invoice if
+       /// they don't support payment metadata fields), you need to call
+       /// [`InvoiceBuilder::require_payment_metadata`] after this.
+       pub fn payment_metadata(mut self, payment_metadata: Vec<u8>) -> InvoiceBuilder<D, H, T, C, S, tb::True> {
+               self.tagged_fields.push(TaggedField::PaymentMetadata(payment_metadata));
+               let mut found_features = false;
+               for field in self.tagged_fields.iter_mut() {
+                       if let TaggedField::Features(f) = field {
+                               found_features = true;
+                               f.set_payment_metadata_optional();
+                       }
+               }
+               if !found_features {
+                       let mut features = InvoiceFeatures::empty();
+                       features.set_payment_metadata_optional();
+                       self.tagged_fields.push(TaggedField::Features(features));
+               }
                self.set_flags()
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T, C, tb::True> {
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, C, S, tb::True> {
+       /// Sets forwarding of payment metadata as required. A reader of the invoice which does not
+       /// support sending payment metadata will fail to read the invoice.
+       pub fn require_payment_metadata(mut self) -> InvoiceBuilder<D, H, T, C, S, tb::True> {
+               for field in self.tagged_fields.iter_mut() {
+                       if let TaggedField::Features(f) = field {
+                               f.set_payment_metadata_required();
+                       }
+               }
+               self
+       }
+}
+
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, M: tb::Bool> InvoiceBuilder<D, H, T, C, tb::True, M> {
        /// Sets the `basic_mpp` feature as optional.
        pub fn basic_mpp(mut self) -> Self {
                for field in self.tagged_fields.iter_mut() {
@@ -683,7 +790,7 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T,
        }
 }
 
-impl InvoiceBuilder<tb::True, tb::True, tb::True, tb::True, tb::True> {
+impl<M: tb::Bool> InvoiceBuilder<tb::True, tb::True, tb::True, tb::True, tb::True, M> {
        /// Builds and signs an invoice using the supplied `sign_function`. This function MAY NOT fail
        /// and MUST produce a recoverable signature valid for the given hash and if applicable also for
        /// the included payee public key.
@@ -739,17 +846,17 @@ impl SignedRawInvoice {
                (self.raw_invoice, self.hash, self.signature)
        }
 
-       /// The `RawInvoice` which was signed.
+       /// The [`RawInvoice`] which was signed.
        pub fn raw_invoice(&self) -> &RawInvoice {
                &self.raw_invoice
        }
 
-       /// The hash of the `RawInvoice` that was signed.
+       /// The hash of the [`RawInvoice`] that was signed.
        pub fn signable_hash(&self) -> &[u8; 32] {
                &self.hash
        }
 
-       /// InvoiceSignature for the invoice.
+       /// Signature for the invoice.
        pub fn signature(&self) -> &InvoiceSignature {
                &self.signature
        }
@@ -779,7 +886,7 @@ impl SignedRawInvoice {
                        recovered_pub_key = Some(recovered);
                }
 
-               let pub_key = included_pub_key.or_else(|| recovered_pub_key.as_ref())
+               let pub_key = included_pub_key.or(recovered_pub_key.as_ref())
                        .expect("One is always present");
 
                let hash = Message::from_slice(&self.hash[..])
@@ -804,6 +911,7 @@ impl SignedRawInvoice {
 ///
 /// The following example would extract the first B.
 ///
+/// ```ignore
 /// enum Enum {
 ///    A(u8),
 ///    B(u16)
@@ -812,6 +920,7 @@ impl SignedRawInvoice {
 /// let elements = vec![Enum::A(1), Enum::A(2), Enum::B(3), Enum::A(4)];
 ///
 /// assert_eq!(find_extract!(elements.iter(), Enum::B(x), x), Some(3u16));
+/// ```
 macro_rules! find_extract {
        ($iter:expr, $enm:pat, $enm_var:ident) => {
                find_all_extract!($iter, $enm, $enm_var).next()
@@ -823,6 +932,7 @@ macro_rules! find_extract {
 ///
 /// The following example would extract all A.
 ///
+/// ```ignore
 /// enum Enum {
 ///    A(u8),
 ///    B(u16)
@@ -834,6 +944,7 @@ macro_rules! find_extract {
 ///    find_all_extract!(elements.iter(), Enum::A(x), x).collect::<Vec<u8>>(),
 ///    vec![1u8, 2u8, 4u8]
 /// );
+/// ```
 macro_rules! find_all_extract {
        ($iter:expr, $enm:pat, $enm_var:ident) => {
                $iter.filter_map(|tf| match *tf {
@@ -863,11 +974,11 @@ impl RawInvoice {
                )
        }
 
-       /// Signs the invoice using the supplied `sign_function`. This function MAY fail with an error
-       /// of type `E`. Since the signature of a `SignedRawInvoice` is not required to be valid there
+       /// Signs the invoice using the supplied `sign_method`. This function MAY fail with an error of
+       /// type `E`. Since the signature of a [`SignedRawInvoice`] is not required to be valid there
        /// are no constraints regarding the validity of the produced signature.
        ///
-       /// (C-not exported) As we don't currently support passing function pointers into methods
+       /// This is not exported to bindings users as we don't currently support passing function pointers into methods
        /// explicitly.
        pub fn sign<F, E>(self, sign_method: F) -> Result<SignedRawInvoice, E>
                where F: FnOnce(&Message) -> Result<RecoverableSignature, E>
@@ -886,7 +997,7 @@ impl RawInvoice {
 
        /// Returns an iterator over all tagged fields with known semantics.
        ///
-       /// (C-not exported) As there is not yet a manual mapping for a FilterMap
+       /// This is not exported to bindings users as there is not yet a manual mapping for a FilterMap
        pub fn known_tagged_fields(&self)
                -> FilterMap<Iter<RawTaggedField>, fn(&RawTaggedField) -> Option<&TaggedField>>
        {
@@ -923,19 +1034,23 @@ impl RawInvoice {
                find_extract!(self.known_tagged_fields(), TaggedField::ExpiryTime(ref x), x)
        }
 
-       pub fn min_final_cltv_expiry(&self) -> Option<&MinFinalCltvExpiry> {
-               find_extract!(self.known_tagged_fields(), TaggedField::MinFinalCltvExpiry(ref x), x)
+       pub fn min_final_cltv_expiry_delta(&self) -> Option<&MinFinalCltvExpiryDelta> {
+               find_extract!(self.known_tagged_fields(), TaggedField::MinFinalCltvExpiryDelta(ref x), x)
        }
 
        pub fn payment_secret(&self) -> Option<&PaymentSecret> {
                find_extract!(self.known_tagged_fields(), TaggedField::PaymentSecret(ref x), x)
        }
 
+       pub fn payment_metadata(&self) -> Option<&Vec<u8>> {
+               find_extract!(self.known_tagged_fields(), TaggedField::PaymentMetadata(ref x), x)
+       }
+
        pub fn features(&self) -> Option<&InvoiceFeatures> {
                find_extract!(self.known_tagged_fields(), TaggedField::Features(ref x), x)
        }
 
-       /// (C-not exported) as we don't support Vec<&NonOpaqueType>
+       /// This is not exported to bindings users as we don't support Vec<&NonOpaqueType>
        pub fn fallbacks(&self) -> Vec<&Fallback> {
                find_all_extract!(self.known_tagged_fields(), TaggedField::Fallback(ref x), x).collect()
        }
@@ -960,12 +1075,18 @@ impl PositiveTimestamp {
        ///
        /// Otherwise, returns a [`CreationError::TimestampOutOfBounds`].
        pub fn from_unix_timestamp(unix_seconds: u64) -> Result<Self, CreationError> {
-               Self::from_duration_since_epoch(Duration::from_secs(unix_seconds))
+               if unix_seconds <= MAX_TIMESTAMP {
+                       Ok(Self(Duration::from_secs(unix_seconds)))
+               } else {
+                       Err(CreationError::TimestampOutOfBounds)
+               }
        }
 
        /// Creates a `PositiveTimestamp` from a [`SystemTime`] with a corresponding Unix timestamp in
        /// the range `0..=MAX_TIMESTAMP`.
        ///
+       /// Note that the subsecond part is dropped as it is not representable in BOLT 11 invoices.
+       ///
        /// Otherwise, returns a [`CreationError::TimestampOutOfBounds`].
        #[cfg(feature = "std")]
        pub fn from_system_time(time: SystemTime) -> Result<Self, CreationError> {
@@ -977,13 +1098,11 @@ impl PositiveTimestamp {
        /// Creates a `PositiveTimestamp` from a [`Duration`] since the Unix epoch in the range
        /// `0..=MAX_TIMESTAMP`.
        ///
+       /// Note that the subsecond part is dropped as it is not representable in BOLT 11 invoices.
+       ///
        /// Otherwise, returns a [`CreationError::TimestampOutOfBounds`].
        pub fn from_duration_since_epoch(duration: Duration) -> Result<Self, CreationError> {
-               if duration.as_secs() <= MAX_TIMESTAMP {
-                       Ok(PositiveTimestamp(duration))
-               } else {
-                       Err(CreationError::TimestampOutOfBounds)
-               }
+               Self::from_unix_timestamp(duration.as_secs())
        }
 
        /// Returns the Unix timestamp representing the stored time
@@ -1004,13 +1123,18 @@ impl PositiveTimestamp {
 }
 
 #[cfg(feature = "std")]
-impl Into<SystemTime> for PositiveTimestamp {
-       fn into(self) -> SystemTime {
-               SystemTime::UNIX_EPOCH + self.0
+impl From<PositiveTimestamp> for SystemTime {
+       fn from(val: PositiveTimestamp) -> Self {
+               SystemTime::UNIX_EPOCH + val.0
        }
 }
 
 impl Invoice {
+       /// The hash of the [`RawInvoice`] that was signed.
+       pub fn signable_hash(&self) -> [u8; 32] {
+               self.signed_invoice.hash
+       }
+
        /// Transform the `Invoice` into it's unchecked version
        pub fn into_signed_raw(self) -> SignedRawInvoice {
                self.signed_invoice
@@ -1115,7 +1239,7 @@ impl Invoice {
                Ok(())
        }
 
-       /// Constructs an `Invoice` from a `SignedRawInvoice` by checking all its invariants.
+       /// Constructs an `Invoice` from a [`SignedRawInvoice`] by checking all its invariants.
        /// ```
        /// use lightning_invoice::*;
        ///
@@ -1137,7 +1261,7 @@ impl Invoice {
        /// ```
        pub fn from_signed(signed_invoice: SignedRawInvoice) -> Result<Self, SemanticError> {
                let invoice = Invoice {
-                       signed_invoice: signed_invoice,
+                       signed_invoice,
                };
                invoice.check_field_counts()?;
                invoice.check_feature_bits()?;
@@ -1160,7 +1284,7 @@ impl Invoice {
 
        /// Returns an iterator over all tagged fields of this Invoice.
        ///
-       /// (C-not exported) As there is not yet a manual mapping for a FilterMap
+       /// This is not exported to bindings users as there is not yet a manual mapping for a FilterMap
        pub fn tagged_fields(&self)
                -> FilterMap<Iter<RawTaggedField>, fn(&RawTaggedField) -> Option<&TaggedField>> {
                self.signed_invoice.raw_invoice().known_tagged_fields()
@@ -1173,11 +1297,11 @@ impl Invoice {
 
        /// Return the description or a hash of it for longer ones
        ///
-       /// (C-not exported) because we don't yet export InvoiceDescription
+       /// This is not exported to bindings users because we don't yet export InvoiceDescription
        pub fn description(&self) -> InvoiceDescription {
-               if let Some(ref direct) = self.signed_invoice.description() {
+               if let Some(direct) = self.signed_invoice.description() {
                        return InvoiceDescription::Direct(direct);
-               } else if let Some(ref hash) = self.signed_invoice.description_hash() {
+               } else if let Some(hash) = self.signed_invoice.description_hash() {
                        return InvoiceDescription::Hash(hash);
                }
                unreachable!("ensured by constructor");
@@ -1193,6 +1317,11 @@ impl Invoice {
                self.signed_invoice.payment_secret().expect("was checked by constructor")
        }
 
+       /// Get the payment metadata blob if one was included in the invoice
+       pub fn payment_metadata(&self) -> Option<&Vec<u8>> {
+               self.signed_invoice.payment_metadata()
+       }
+
        /// Get the invoice features if they were included in the invoice
        pub fn features(&self) -> Option<&InvoiceFeatures> {
                self.signed_invoice.features()
@@ -1203,6 +1332,12 @@ impl Invoice {
                self.signed_invoice.recover_payee_pub_key().expect("was checked by constructor").0
        }
 
+       /// Returns the Duration since the Unix epoch at which the invoice expires.
+       /// Returning None if overflow occurred.
+       pub fn expires_at(&self) -> Option<Duration> {
+               self.duration_since_epoch().checked_add(self.expiry_time())
+       }
+
        /// Returns the invoice's expiry time, if present, otherwise [`DEFAULT_EXPIRY_TIME`].
        pub fn expiry_time(&self) -> Duration {
                self.signed_invoice.expiry_time()
@@ -1225,6 +1360,20 @@ impl Invoice {
                }
        }
 
+       /// Returns the Duration remaining until the invoice expires.
+       #[cfg(feature = "std")]
+       pub fn duration_until_expiry(&self) -> Duration {
+               SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)
+                       .map(|now| self.expiration_remaining_from_epoch(now))
+                       .unwrap_or(Duration::from_nanos(0))
+       }
+
+       /// Returns the Duration remaining until the invoice expires given the current time.
+       /// `time` is the timestamp as a duration since the Unix epoch.
+       pub fn expiration_remaining_from_epoch(&self, time: Duration) -> Duration {
+               self.expires_at().map(|x| x.checked_sub(time)).flatten().unwrap_or(Duration::from_nanos(0))
+       }
+
        /// Returns whether the expiry time would pass at the given point in time.
        /// `at_time` is the timestamp as a duration since the Unix epoch.
        pub fn would_expire(&self, at_time: Duration) -> bool {
@@ -1233,21 +1382,40 @@ impl Invoice {
                        .unwrap_or_else(|| Duration::new(u64::max_value(), 1_000_000_000 - 1)) < at_time
        }
 
-       /// Returns the invoice's `min_final_cltv_expiry` time, if present, otherwise
-       /// [`DEFAULT_MIN_FINAL_CLTV_EXPIRY`].
-       pub fn min_final_cltv_expiry(&self) -> u64 {
-               self.signed_invoice.min_final_cltv_expiry()
+       /// Returns the invoice's `min_final_cltv_expiry_delta` time, if present, otherwise
+       /// [`DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA`].
+       pub fn min_final_cltv_expiry_delta(&self) -> u64 {
+               self.signed_invoice.min_final_cltv_expiry_delta()
                        .map(|x| x.0)
-                       .unwrap_or(DEFAULT_MIN_FINAL_CLTV_EXPIRY)
+                       .unwrap_or(DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA)
        }
 
        /// Returns a list of all fallback addresses
        ///
-       /// (C-not exported) as we don't support Vec<&NonOpaqueType>
+       /// This is not exported to bindings users as we don't support Vec<&NonOpaqueType>
        pub fn fallbacks(&self) -> Vec<&Fallback> {
                self.signed_invoice.fallbacks()
        }
 
+       /// Returns a list of all fallback addresses as [`Address`]es
+       pub fn fallback_addresses(&self) -> Vec<Address> {
+               self.fallbacks().iter().map(|fallback| {
+                       let payload = match fallback {
+                               Fallback::SegWitProgram { version, program } => {
+                                       Payload::WitnessProgram { version: *version, program: program.to_vec() }
+                               }
+                               Fallback::PubKeyHash(pkh) => {
+                                       Payload::PubkeyHash(*pkh)
+                               }
+                               Fallback::ScriptHash(sh) => {
+                                       Payload::ScriptHash(*sh)
+                               }
+                       };
+
+                       Address { payload, network: self.network() }
+               }).collect()
+       }
+
        /// Returns a list of all routes included in the invoice
        pub fn private_routes(&self) -> Vec<&PrivateRoute> {
                self.signed_invoice.private_routes()
@@ -1265,12 +1433,19 @@ impl Invoice {
                self.signed_invoice.currency()
        }
 
+       /// Returns the network for which the invoice was issued
+       ///
+       /// This is not exported to bindings users, see [`Self::currency`] instead.
+       pub fn network(&self) -> Network {
+               self.signed_invoice.currency().into()
+       }
+
        /// Returns the amount if specified in the invoice as millisatoshis.
        pub fn amount_milli_satoshis(&self) -> Option<u64> {
                self.signed_invoice.amount_pico_btc().map(|v| v / 10)
        }
 
-       /// Returns the amount if specified in the invoice as pico <currency>.
+       /// Returns the amount if specified in the invoice as pico BTC.
        fn amount_pico_btc(&self) -> Option<u64> {
                self.signed_invoice.amount_pico_btc()
        }
@@ -1291,10 +1466,11 @@ impl TaggedField {
                        TaggedField::PayeePubKey(_) => constants::TAG_PAYEE_PUB_KEY,
                        TaggedField::DescriptionHash(_) => constants::TAG_DESCRIPTION_HASH,
                        TaggedField::ExpiryTime(_) => constants::TAG_EXPIRY_TIME,
-                       TaggedField::MinFinalCltvExpiry(_) => constants::TAG_MIN_FINAL_CLTV_EXPIRY,
+                       TaggedField::MinFinalCltvExpiryDelta(_) => constants::TAG_MIN_FINAL_CLTV_EXPIRY_DELTA,
                        TaggedField::Fallback(_) => constants::TAG_FALLBACK,
                        TaggedField::PrivateRoute(_) => constants::TAG_PRIVATE_ROUTE,
                        TaggedField::PaymentSecret(_) => constants::TAG_PAYMENT_SECRET,
+                       TaggedField::PaymentMetadata(_) => constants::TAG_PAYMENT_METADATA,
                        TaggedField::Features(_) => constants::TAG_FEATURES,
                };
 
@@ -1305,7 +1481,7 @@ impl TaggedField {
 impl Description {
 
        /// Creates a new `Description` if `description` is at most 1023 __bytes__ long,
-       /// returns `CreationError::DescriptionTooLong` otherwise
+       /// returns [`CreationError::DescriptionTooLong`] otherwise
        ///
        /// Please note that single characters may use more than one byte due to UTF8 encoding.
        pub fn new(description: String) -> Result<Description, CreationError> {
@@ -1316,15 +1492,15 @@ impl Description {
                }
        }
 
-       /// Returns the underlying description `String`
+       /// Returns the underlying description [`String`]
        pub fn into_inner(self) -> String {
                self.0
        }
 }
 
-impl Into<String> for Description {
-       fn into(self) -> String {
-               self.into_inner()
+impl From<Description> for String {
+       fn from(val: Description) -> Self {
+               val.into_inner()
        }
 }
 
@@ -1356,9 +1532,9 @@ impl ExpiryTime {
                ExpiryTime(Duration::from_secs(seconds))
        }
 
-       /// Construct an `ExpiryTime` from a `Duration`.
+       /// Construct an `ExpiryTime` from a [`Duration`], dropping the sub-second part.
        pub fn from_duration(duration: Duration) -> ExpiryTime {
-               ExpiryTime(duration)
+               Self::from_seconds(duration.as_secs())
        }
 
        /// Returns the expiry time in seconds
@@ -1366,7 +1542,7 @@ impl ExpiryTime {
                self.0.as_secs()
        }
 
-       /// Returns a reference to the underlying `Duration` (=expiry time)
+       /// Returns a reference to the underlying [`Duration`] (=expiry time)
        pub fn as_duration(&self) -> &Duration {
                &self.0
        }
@@ -1388,9 +1564,9 @@ impl PrivateRoute {
        }
 }
 
-impl Into<RouteHint> for PrivateRoute {
-       fn into(self) -> RouteHint {
-               self.into_inner()
+impl From<PrivateRoute> for RouteHint {
+       fn from(val: PrivateRoute) -> Self {
+               val.into_inner()
        }
 }
 
@@ -1418,10 +1594,10 @@ impl Deref for SignedRawInvoice {
        }
 }
 
-/// Errors that may occur when constructing a new `RawInvoice` or `Invoice`
+/// Errors that may occur when constructing a new [`RawInvoice`] or [`Invoice`]
 #[derive(Eq, PartialEq, Debug, Clone)]
 pub enum CreationError {
-       /// The supplied description string was longer than 639 __bytes__ (see [`Description::new(…)`](./struct.Description.html#method.new))
+       /// The supplied description string was longer than 639 __bytes__ (see [`Description::new`])
        DescriptionTooLong,
 
        /// The specified route has too many hops and can't be encoded
@@ -1438,6 +1614,11 @@ pub enum CreationError {
        ///
        /// [phantom invoices]: crate::utils::create_phantom_invoice
        MissingRouteHints,
+
+       /// The provided `min_final_cltv_expiry_delta` was less than [`MIN_FINAL_CLTV_EXPIRY_DELTA`].
+       ///
+       /// [`MIN_FINAL_CLTV_EXPIRY_DELTA`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA
+       MinFinalCltvExpiryDeltaTooShort,
 }
 
 impl Display for CreationError {
@@ -1448,6 +1629,8 @@ impl Display for CreationError {
                        CreationError::TimestampOutOfBounds => f.write_str("The Unix timestamp of the supplied date is less than zero or greater than 35-bits"),
                        CreationError::InvalidAmount => f.write_str("The supplied millisatoshi amount was greater than the total bitcoin supply"),
                        CreationError::MissingRouteHints => f.write_str("The invoice required route hints and they weren't provided"),
+                       CreationError::MinFinalCltvExpiryDeltaTooShort => f.write_str(
+                               "The supplied final CLTV expiry delta was less than LDK's `MIN_FINAL_CLTV_EXPIRY_DELTA`"),
                }
        }
 }
@@ -1455,7 +1638,7 @@ impl Display for CreationError {
 #[cfg(feature = "std")]
 impl std::error::Error for CreationError { }
 
-/// Errors that may occur when converting a `RawInvoice` to an `Invoice`. They relate to the
+/// Errors that may occur when converting a [`RawInvoice`] to an [`Invoice`]. They relate to the
 /// requirements sections in BOLT #11
 #[derive(Eq, PartialEq, Debug, Clone)]
 pub enum SemanticError {
@@ -1511,7 +1694,7 @@ impl Display for SemanticError {
 #[cfg(feature = "std")]
 impl std::error::Error for SemanticError { }
 
-/// When signing using a fallible method either an user-supplied `SignError` or a `CreationError`
+/// When signing using a fallible method either an user-supplied `SignError` or a [`CreationError`]
 /// may occur.
 #[derive(Eq, PartialEq, Debug, Clone)]
 pub enum SignOrCreationError<S = ()> {
@@ -1542,7 +1725,7 @@ impl<'de> Deserialize<'de> for Invoice {
        fn deserialize<D>(deserializer: D) -> Result<Invoice, D::Error> where D: Deserializer<'de> {
                let bolt11 = String::deserialize(deserializer)?
                        .parse::<Invoice>()
-                       .map_err(|e| D::Error::custom(format!("{:?}", e)))?;
+                       .map_err(|e| D::Error::custom(format_args!("{:?}", e)))?;
 
                Ok(bolt11)
        }
@@ -1550,21 +1733,22 @@ impl<'de> Deserialize<'de> for Invoice {
 
 #[cfg(test)]
 mod test {
+       use bitcoin::Script;
        use bitcoin_hashes::hex::FromHex;
        use bitcoin_hashes::sha256;
 
        #[test]
        fn test_system_time_bounds_assumptions() {
                assert_eq!(
-                       ::PositiveTimestamp::from_unix_timestamp(::MAX_TIMESTAMP + 1),
-                       Err(::CreationError::TimestampOutOfBounds)
+                       crate::PositiveTimestamp::from_unix_timestamp(crate::MAX_TIMESTAMP + 1),
+                       Err(crate::CreationError::TimestampOutOfBounds)
                );
        }
 
        #[test]
        fn test_calc_invoice_hash() {
-               use ::{RawInvoice, RawHrp, RawDataPart, Currency, PositiveTimestamp};
-               use ::TaggedField::*;
+               use crate::{RawInvoice, RawHrp, RawDataPart, Currency, PositiveTimestamp};
+               use crate::TaggedField::*;
 
                let invoice = RawInvoice {
                        hrp: RawHrp {
@@ -1575,10 +1759,10 @@ mod test {
                        data: RawDataPart {
                                timestamp: PositiveTimestamp::from_unix_timestamp(1496314658).unwrap(),
                                tagged_fields: vec![
-                                       PaymentHash(::Sha256(sha256::Hash::from_hex(
+                                       PaymentHash(crate::Sha256(sha256::Hash::from_hex(
                                                "0001020304050607080900010203040506070809000102030405060708090102"
                                        ).unwrap())).into(),
-                                       Description(::Description::new(
+                                       Description(crate::Description::new(
                                                "Please consider supporting this project".to_owned()
                                        ).unwrap()).into(),
                                ],
@@ -1596,11 +1780,11 @@ mod test {
 
        #[test]
        fn test_check_signature() {
-               use TaggedField::*;
+               use crate::TaggedField::*;
                use secp256k1::Secp256k1;
                use secp256k1::ecdsa::{RecoveryId, RecoverableSignature};
                use secp256k1::{SecretKey, PublicKey};
-               use {SignedRawInvoice, InvoiceSignature, RawInvoice, RawHrp, RawDataPart, Currency, Sha256,
+               use crate::{SignedRawInvoice, InvoiceSignature, RawInvoice, RawHrp, RawDataPart, Currency, Sha256,
                         PositiveTimestamp};
 
                let invoice = SignedRawInvoice {
@@ -1617,7 +1801,7 @@ mod test {
                                                        "0001020304050607080900010203040506070809000102030405060708090102"
                                                ).unwrap())).into(),
                                                Description(
-                                                       ::Description::new(
+                                                       crate::Description::new(
                                                                "Please consider supporting this project".to_owned()
                                                        ).unwrap()
                                                ).into(),
@@ -1653,7 +1837,7 @@ mod test {
                ).unwrap();
                let public_key = PublicKey::from_secret_key(&Secp256k1::new(), &private_key);
 
-               assert_eq!(invoice.recover_payee_pub_key(), Ok(::PayeePubKey(public_key)));
+               assert_eq!(invoice.recover_payee_pub_key(), Ok(crate::PayeePubKey(public_key)));
 
                let (raw_invoice, _, _) = invoice.into_parts();
                let new_signed = raw_invoice.sign::<_, ()>(|hash| {
@@ -1665,11 +1849,11 @@ mod test {
 
        #[test]
        fn test_check_feature_bits() {
-               use TaggedField::*;
+               use crate::TaggedField::*;
                use lightning::ln::features::InvoiceFeatures;
                use secp256k1::Secp256k1;
                use secp256k1::SecretKey;
-               use {RawInvoice, RawHrp, RawDataPart, Currency, Sha256, PositiveTimestamp, Invoice,
+               use crate::{RawInvoice, RawHrp, RawDataPart, Currency, Sha256, PositiveTimestamp, Invoice,
                         SemanticError};
 
                let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
@@ -1687,7 +1871,7 @@ mod test {
                                                "0001020304050607080900010203040506070809000102030405060708090102"
                                        ).unwrap())).into(),
                                        Description(
-                                               ::Description::new(
+                                               crate::Description::new(
                                                        "Please consider supporting this project".to_owned()
                                                ).unwrap()
                                        ).into(),
@@ -1712,11 +1896,14 @@ mod test {
                }.unwrap();
                assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::InvalidFeatures));
 
+               let mut payment_secret_features = InvoiceFeatures::empty();
+               payment_secret_features.set_payment_secret_required();
+
                // Including payment secret and feature bits
                let invoice = {
                        let mut invoice = invoice_template.clone();
                        invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
-                       invoice.data.tagged_fields.push(Features(InvoiceFeatures::known()).into());
+                       invoice.data.tagged_fields.push(Features(payment_secret_features.clone()).into());
                        invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
                }.unwrap();
                assert!(Invoice::from_signed(invoice).is_ok());
@@ -1739,14 +1926,14 @@ mod test {
                // Missing payment secret
                let invoice = {
                        let mut invoice = invoice_template.clone();
-                       invoice.data.tagged_fields.push(Features(InvoiceFeatures::known()).into());
+                       invoice.data.tagged_fields.push(Features(payment_secret_features).into());
                        invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
                }.unwrap();
                assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::NoPaymentSecret));
 
                // Multiple payment secrets
                let invoice = {
-                       let mut invoice = invoice_template.clone();
+                       let mut invoice = invoice_template;
                        invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
                        invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
                        invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
@@ -1756,7 +1943,7 @@ mod test {
 
        #[test]
        fn test_builder_amount() {
-               use ::*;
+               use crate::*;
 
                let builder = InvoiceBuilder::new(Currency::Bitcoin)
                        .description("Test".into())
@@ -1772,7 +1959,7 @@ mod test {
                assert_eq!(invoice.hrp.raw_amount, Some(15));
 
 
-               let invoice = builder.clone()
+               let invoice = builder
                        .amount_milli_satoshis(150)
                        .build_raw()
                        .unwrap();
@@ -1783,7 +1970,7 @@ mod test {
 
        #[test]
        fn test_builder_fail() {
-               use ::*;
+               use crate::*;
                use lightning::routing::router::RouteHintHop;
                use std::iter::FromIterator;
                use secp256k1::PublicKey;
@@ -1791,7 +1978,7 @@ mod test {
                let builder = InvoiceBuilder::new(Currency::Bitcoin)
                        .payment_hash(sha256::Hash::from_slice(&[0;32][..]).unwrap())
                        .duration_since_epoch(Duration::from_secs(1234567))
-                       .min_final_cltv_expiry(144);
+                       .min_final_cltv_expiry_delta(144);
 
                let too_long_string = String::from_iter(
                        (0..1024).map(|_| '?')
@@ -1826,7 +2013,7 @@ mod test {
                        .build_raw();
                assert_eq!(long_route_res, Err(CreationError::RouteTooLong));
 
-               let sign_error_res = builder.clone()
+               let sign_error_res = builder
                        .description("Test".into())
                        .payment_secret(PaymentSecret([0; 32]))
                        .try_build_signed(|_| {
@@ -1837,7 +2024,7 @@ mod test {
 
        #[test]
        fn test_builder_ok() {
-               use ::*;
+               use crate::*;
                use lightning::routing::router::RouteHintHop;
                use secp256k1::Secp256k1;
                use secp256k1::{SecretKey, PublicKey};
@@ -1856,7 +2043,7 @@ mod test {
 
                let route_1 = RouteHint(vec![
                        RouteHintHop {
-                               src_node_id: public_key.clone(),
+                               src_node_id: public_key,
                                short_channel_id: de::parse_int_be(&[123; 8], 256).expect("short chan ID slice too big?"),
                                fees: RoutingFees {
                                        base_msat: 2,
@@ -1867,7 +2054,7 @@ mod test {
                                htlc_maximum_msat: None,
                        },
                        RouteHintHop {
-                               src_node_id: public_key.clone(),
+                               src_node_id: public_key,
                                short_channel_id: de::parse_int_be(&[42; 8], 256).expect("short chan ID slice too big?"),
                                fees: RoutingFees {
                                        base_msat: 3,
@@ -1881,7 +2068,7 @@ mod test {
 
                let route_2 = RouteHint(vec![
                        RouteHintHop {
-                               src_node_id: public_key.clone(),
+                               src_node_id: public_key,
                                short_channel_id: 0,
                                fees: RoutingFees {
                                        base_msat: 4,
@@ -1892,7 +2079,7 @@ mod test {
                                htlc_maximum_msat: None,
                        },
                        RouteHintHop {
-                               src_node_id: public_key.clone(),
+                               src_node_id: public_key,
                                short_channel_id: de::parse_int_be(&[1; 8], 256).expect("short chan ID slice too big?"),
                                fees: RoutingFees {
                                        base_msat: 5,
@@ -1907,10 +2094,10 @@ mod test {
                let builder = InvoiceBuilder::new(Currency::BitcoinTestnet)
                        .amount_milli_satoshis(123)
                        .duration_since_epoch(Duration::from_secs(1234567))
-                       .payee_pub_key(public_key.clone())
+                       .payee_pub_key(public_key)
                        .expiry_time(Duration::from_secs(54321))
-                       .min_final_cltv_expiry(144)
-                       .fallback(Fallback::PubKeyHash([0;20]))
+                       .min_final_cltv_expiry_delta(144)
+                       .fallback(Fallback::PubKeyHash(PubkeyHash::from_slice(&[0;20]).unwrap()))
                        .private_route(route_1.clone())
                        .private_route(route_2.clone())
                        .description_hash(sha256::Hash::from_slice(&[3;32][..]).unwrap())
@@ -1935,8 +2122,10 @@ mod test {
                );
                assert_eq!(invoice.payee_pub_key(), Some(&public_key));
                assert_eq!(invoice.expiry_time(), Duration::from_secs(54321));
-               assert_eq!(invoice.min_final_cltv_expiry(), 144);
-               assert_eq!(invoice.fallbacks(), vec![&Fallback::PubKeyHash([0;20])]);
+               assert_eq!(invoice.min_final_cltv_expiry_delta(), 144);
+               assert_eq!(invoice.fallbacks(), vec![&Fallback::PubKeyHash(PubkeyHash::from_slice(&[0;20]).unwrap())]);
+               let address = Address::from_script(&Script::new_p2pkh(&PubkeyHash::from_slice(&[0;20]).unwrap()), Network::Testnet).unwrap();
+               assert_eq!(invoice.fallback_addresses(), vec![address]);
                assert_eq!(invoice.private_routes(), vec![&PrivateRoute(route_1), &PrivateRoute(route_2)]);
                assert_eq!(
                        invoice.description(),
@@ -1944,7 +2133,12 @@ mod test {
                );
                assert_eq!(invoice.payment_hash(), &sha256::Hash::from_slice(&[21;32][..]).unwrap());
                assert_eq!(invoice.payment_secret(), &PaymentSecret([42; 32]));
-               assert_eq!(invoice.features(), Some(&InvoiceFeatures::known()));
+
+               let mut expected_features = InvoiceFeatures::empty();
+               expected_features.set_variable_length_onion_required();
+               expected_features.set_payment_secret_required();
+               expected_features.set_basic_mpp_optional();
+               assert_eq!(invoice.features(), Some(&expected_features));
 
                let raw_invoice = builder.build_raw().unwrap();
                assert_eq!(raw_invoice, *invoice.into_signed_raw().raw_invoice())
@@ -1952,7 +2146,7 @@ mod test {
 
        #[test]
        fn test_default_values() {
-               use ::*;
+               use crate::*;
                use secp256k1::Secp256k1;
                use secp256k1::SecretKey;
 
@@ -1971,14 +2165,14 @@ mod test {
                        .unwrap();
                let invoice = Invoice::from_signed(signed_invoice).unwrap();
 
-               assert_eq!(invoice.min_final_cltv_expiry(), DEFAULT_MIN_FINAL_CLTV_EXPIRY);
+               assert_eq!(invoice.min_final_cltv_expiry_delta(), DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA);
                assert_eq!(invoice.expiry_time(), Duration::from_secs(DEFAULT_EXPIRY_TIME));
                assert!(!invoice.would_expire(Duration::from_secs(1234568)));
        }
 
        #[test]
        fn test_expiration() {
-               use ::*;
+               use crate::*;
                use secp256k1::Secp256k1;
                use secp256k1::SecretKey;