Merge pull request #909 from TheBlueMatt/2021-04-0.0.14
[rust-lightning] / lightning-invoice / src / lib.rs
index 461ae9b92ad1a9e4d9bb993c13bae59353e89dd0..29c093dec95925f19f86d745ecdf54bd98856851 100644 (file)
@@ -168,7 +168,7 @@ pub fn check_platform() {
 ///
 /// (C-not exported) 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> {
+pub struct InvoiceBuilder<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> {
        currency: Currency,
        amount: Option<u64>,
        si_prefix: Option<SiPrefix>,
@@ -180,6 +180,7 @@ pub struct InvoiceBuilder<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> {
        phantom_h: std::marker::PhantomData<H>,
        phantom_t: std::marker::PhantomData<T>,
        phantom_c: std::marker::PhantomData<C>,
+       phantom_s: std::marker::PhantomData<S>,
 }
 
 /// Represents a syntactically and semantically correct lightning BOLT11 invoice.
@@ -332,6 +333,8 @@ pub enum Currency {
 }
 
 /// Tagged field which may have an unknown tag
+///
+/// (C-not exported) as we don't currently support TaggedField
 #[derive(Eq, PartialEq, Debug, Clone)]
 pub enum RawTaggedField {
        /// Parsed tagged field with known tag
@@ -343,6 +346,9 @@ pub enum RawTaggedField {
 /// Tagged field with known tag
 ///
 /// 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
+/// in the variant.
 #[allow(missing_docs)]
 #[derive(Eq, PartialEq, Debug, Clone)]
 pub enum TaggedField {
@@ -427,7 +433,7 @@ pub mod constants {
        pub const TAG_FEATURES: u8 = 5;
 }
 
-impl InvoiceBuilder<tb::False, tb::False, tb::False, tb::False> {
+impl InvoiceBuilder<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 {
@@ -443,14 +449,15 @@ impl InvoiceBuilder<tb::False, tb::False, tb::False, tb::False> {
                        phantom_h: std::marker::PhantomData,
                        phantom_t: std::marker::PhantomData,
                        phantom_c: std::marker::PhantomData,
+                       phantom_s: std::marker::PhantomData,
                }
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T, C> {
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, C, S> {
        /// Helper function to set the completeness flags.
-       fn set_flags<DN: tb::Bool, HN: tb::Bool, TN: tb::Bool, CN: tb::Bool>(self) -> InvoiceBuilder<DN, HN, TN, CN> {
-               InvoiceBuilder::<DN, HN, TN, CN> {
+       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> {
                        currency: self.currency,
                        amount: self.amount,
                        si_prefix: self.si_prefix,
@@ -462,6 +469,7 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T,
                        phantom_h: std::marker::PhantomData,
                        phantom_t: std::marker::PhantomData,
                        phantom_c: std::marker::PhantomData,
+                       phantom_s: std::marker::PhantomData,
                }
        }
 
@@ -482,12 +490,6 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T,
                self
        }
 
-       /// Sets the payment secret
-       pub fn payment_secret(mut self, payment_secret: PaymentSecret) -> Self {
-               self.tagged_fields.push(TaggedField::PaymentSecret(payment_secret));
-               self
-       }
-
        /// Sets the expiry time
        pub fn expiry_time(mut self, expiry_time: Duration) -> Self {
         match ExpiryTime::from_duration(expiry_time) {
@@ -511,16 +513,9 @@ impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T,
                }
                self
        }
-
-       /// Adds a features field which indicates the set of supported protocol extensions which the
-       /// origin node supports.
-       pub fn features(mut self, features: InvoiceFeatures) -> Self {
-               self.tagged_fields.push(TaggedField::Features(features));
-               self
-       }
 }
 
-impl<D: tb::Bool, H: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, tb::True, C> {
+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.
        pub fn build_raw(self) -> Result<RawInvoice, CreationError> {
 
@@ -553,9 +548,9 @@ impl<D: tb::Bool, H: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, tb::True, C> {
        }
 }
 
-impl<H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<tb::False, H, T, C> {
+impl<H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<tb::False, H, T, C, S> {
        /// 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> {
+       pub fn description(mut self, description: String) -> InvoiceBuilder<tb::True, H, T, C, S> {
                match Description::new(description) {
                        Ok(d) => self.tagged_fields.push(TaggedField::Description(d)),
                        Err(e) => self.error = Some(e),
@@ -564,23 +559,23 @@ impl<H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<tb::False, H, T, C> {
        }
 
        /// 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> {
+       pub fn description_hash(mut self, description_hash: sha256::Hash) -> InvoiceBuilder<tb::True, H, T, C, S> {
                self.tagged_fields.push(TaggedField::DescriptionHash(Sha256(description_hash)));
                self.set_flags()
        }
 }
 
-impl<D: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, tb::False, T, C> {
+impl<D: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, tb::False, T, C, S> {
        /// 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> {
+       pub fn payment_hash(mut self, hash: sha256::Hash) -> InvoiceBuilder<D, tb::True, T, C, S> {
                self.tagged_fields.push(TaggedField::PaymentHash(Sha256(hash)));
                self.set_flags()
        }
 }
 
-impl<D: tb::Bool, H: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, tb::False, C> {
+impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb::False, C, S> {
        /// Sets the timestamp.
-       pub fn timestamp(mut self, time: SystemTime) -> InvoiceBuilder<D, H, tb::True, C> {
+       pub fn timestamp(mut self, time: SystemTime) -> InvoiceBuilder<D, H, tb::True, C, S> {
                match PositiveTimestamp::from_system_time(time) {
                        Ok(t) => self.timestamp = Some(t),
                        Err(e) => self.error = Some(e),
@@ -590,22 +585,48 @@ impl<D: tb::Bool, H: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, tb::False, C> {
        }
 
        /// Sets the timestamp to the current UNIX timestamp.
-       pub fn current_timestamp(mut self) -> InvoiceBuilder<D, H, tb::True, C> {
+       pub fn current_timestamp(mut self) -> InvoiceBuilder<D, H, tb::True, C, S> {
                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> InvoiceBuilder<D, H, T, tb::False> {
+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> {
+       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)));
                self.set_flags()
        }
 }
 
-impl InvoiceBuilder<tb::True, tb::True, tb::True, tb::True> {
+impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T, C, tb::False> {
+       /// Sets the payment secret and relevant features.
+       pub fn payment_secret(mut self, payment_secret: PaymentSecret) -> InvoiceBuilder<D, H, T, C, tb::True> {
+               let features = InvoiceFeatures::empty()
+                       .set_variable_length_onion_required()
+                       .set_payment_secret_required();
+               self.tagged_fields.push(TaggedField::PaymentSecret(payment_secret));
+               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> {
+       /// Sets the `basic_mpp` feature as optional.
+       pub fn basic_mpp(mut self) -> Self {
+               self.tagged_fields = self.tagged_fields
+                       .drain(..)
+                       .map(|field| match field {
+                               TaggedField::Features(f) => TaggedField::Features(f.set_basic_mpp_optional()),
+                               _ => field,
+                       })
+                       .collect();
+               self
+       }
+}
+
+impl<S: tb::Bool> InvoiceBuilder<tb::True, tb::True, tb::True, tb::True, S> {
        /// 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.
@@ -644,6 +665,7 @@ impl InvoiceBuilder<tb::True, tb::True, tb::True, tb::True> {
                };
 
                invoice.check_field_counts().expect("should be ensured by type signature of builder");
+               invoice.check_feature_bits().expect("should be ensured by type signature of builder");
 
                Ok(invoice)
        }
@@ -972,6 +994,41 @@ impl Invoice {
                Ok(())
        }
 
+       /// Check that feature bits are set as required
+       fn check_feature_bits(&self) -> Result<(), SemanticError> {
+               // "If the payment_secret feature is set, MUST include exactly one s field."
+               let payment_secret_count = self.tagged_fields().filter(|&tf| match *tf {
+                       TaggedField::PaymentSecret(_) => true,
+                       _ => false,
+               }).count();
+               if payment_secret_count > 1 {
+                       return Err(SemanticError::MultiplePaymentSecrets);
+               }
+
+               // "A writer MUST set an s field if and only if the payment_secret feature is set."
+               let has_payment_secret = payment_secret_count == 1;
+               let features = self.tagged_fields().find(|&tf| match *tf {
+                       TaggedField::Features(_) => true,
+                       _ => false,
+               });
+               match features {
+                       None if has_payment_secret => Err(SemanticError::InvalidFeatures),
+                       None => Ok(()),
+                       Some(TaggedField::Features(features)) => {
+                               if features.supports_payment_secret() && has_payment_secret {
+                                       Ok(())
+                               } else if has_payment_secret {
+                                       Err(SemanticError::InvalidFeatures)
+                               } else if features.supports_payment_secret() {
+                                       Err(SemanticError::InvalidFeatures)
+                               } else {
+                                       Ok(())
+                               }
+                       },
+                       Some(_) => unreachable!(),
+               }
+       }
+
        /// Check that the invoice is signed correctly and that key recovery works
        pub fn check_signature(&self) -> Result<(), SemanticError> {
                match self.signed_invoice.recover_payee_pub_key() {
@@ -1006,6 +1063,7 @@ impl Invoice {
                        signed_invoice: signed_invoice,
                };
                invoice.check_field_counts()?;
+               invoice.check_feature_bits()?;
                invoice.check_signature()?;
 
                Ok(invoice)
@@ -1298,6 +1356,12 @@ pub enum SemanticError {
        /// The invoice contains multiple descriptions and/or description hashes which isn't allowed
        MultipleDescriptions,
 
+       /// The invoice contains multiple payment secrets
+       MultiplePaymentSecrets,
+
+       /// The invoice's features are invalid
+       InvalidFeatures,
+
        /// The recovery id doesn't fit the signature/pub key
        InvalidRecoveryId,
 
@@ -1312,6 +1376,8 @@ impl Display for SemanticError {
                        SemanticError::MultiplePaymentHashes => f.write_str("The invoice has multiple payment hashes which isn't allowed"),
                        SemanticError::NoDescription => f.write_str("No description or description hash are part of the invoice"),
                        SemanticError::MultipleDescriptions => f.write_str("The invoice contains multiple descriptions and/or description hashes which isn't allowed"),
+                       SemanticError::MultiplePaymentSecrets => f.write_str("The invoice contains multiple payment secrets"),
+                       SemanticError::InvalidFeatures => f.write_str("The invoice's features are invalid"),
                        SemanticError::InvalidRecoveryId => f.write_str("The recovery id doesn't fit the signature/pub key"),
                        SemanticError::InvalidSignature => f.write_str("The invoice's signature is invalid"),
                }
@@ -1322,10 +1388,8 @@ impl std::error::Error for SemanticError { }
 
 /// When signing using a fallible method either an user-supplied `SignError` or a `CreationError`
 /// may occur.
-///
-/// (C-not exported) As we don't support unbounded generics
 #[derive(Eq, PartialEq, Debug, Clone)]
-pub enum SignOrCreationError<S> {
+pub enum SignOrCreationError<S = ()> {
        /// An error occurred during signing
        SignError(S),
 
@@ -1464,6 +1528,97 @@ mod test {
                assert!(new_signed.check_signature());
        }
 
+       #[test]
+       fn test_check_feature_bits() {
+               use TaggedField::*;
+               use lightning::ln::features::InvoiceFeatures;
+               use secp256k1::Secp256k1;
+               use secp256k1::key::SecretKey;
+               use {RawInvoice, RawHrp, RawDataPart, Currency, Sha256, PositiveTimestamp, Invoice,
+                        SemanticError};
+
+               let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
+               let payment_secret = lightning::ln::PaymentSecret([21; 32]);
+               let invoice_template = RawInvoice {
+                       hrp: RawHrp {
+                               currency: Currency::Bitcoin,
+                               raw_amount: None,
+                               si_prefix: None,
+                       },
+                       data: RawDataPart {
+                               timestamp: PositiveTimestamp::from_unix_timestamp(1496314658).unwrap(),
+                               tagged_fields: vec ! [
+                                       PaymentHash(Sha256(sha256::Hash::from_hex(
+                                               "0001020304050607080900010203040506070809000102030405060708090102"
+                                       ).unwrap())).into(),
+                                       Description(
+                                               ::Description::new(
+                                                       "Please consider supporting this project".to_owned()
+                                               ).unwrap()
+                                       ).into(),
+                               ],
+                       },
+               };
+
+               // Missing features
+               let invoice = {
+                       let mut invoice = invoice_template.clone();
+                       invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
+                       invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::InvalidFeatures));
+
+               // Missing 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::empty()).into());
+                       invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::InvalidFeatures));
+
+               // 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.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert!(Invoice::from_signed(invoice).is_ok());
+
+               // No payment secret or features
+               let invoice = {
+                       let invoice = invoice_template.clone();
+                       invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert!(Invoice::from_signed(invoice).is_ok());
+
+               // No payment secret or feature bits
+               let invoice = {
+                       let mut invoice = invoice_template.clone();
+                       invoice.data.tagged_fields.push(Features(InvoiceFeatures::empty()).into());
+                       invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert!(Invoice::from_signed(invoice).is_ok());
+
+               // Missing payment secret
+               let invoice = {
+                       let mut invoice = invoice_template.clone();
+                       invoice.data.tagged_fields.push(Features(InvoiceFeatures::known()).into());
+                       invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::InvalidFeatures));
+
+               // Multiple payment secrets
+               let invoice = {
+                       let mut invoice = invoice_template.clone();
+                       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_recoverable(hash, &private_key)))
+               }.unwrap();
+               assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::MultiplePaymentSecrets));
+       }
+
        #[test]
        fn test_builder_amount() {
                use ::*;
@@ -1621,14 +1776,16 @@ mod test {
                        .route(route_1.clone())
                        .route(route_2.clone())
                        .description_hash(sha256::Hash::from_slice(&[3;32][..]).unwrap())
-                       .payment_hash(sha256::Hash::from_slice(&[21;32][..]).unwrap());
+                       .payment_hash(sha256::Hash::from_slice(&[21;32][..]).unwrap())
+                       .payment_secret(PaymentSecret([42; 32]))
+                       .basic_mpp();
 
                let invoice = builder.clone().build_signed(|hash| {
                        secp_ctx.sign_recoverable(hash, &private_key)
                }).unwrap();
 
                assert!(invoice.check_signature().is_ok());
-               assert_eq!(invoice.tagged_fields().count(), 8);
+               assert_eq!(invoice.tagged_fields().count(), 10);
 
                assert_eq!(invoice.amount_pico_btc(), Some(123));
                assert_eq!(invoice.currency(), Currency::BitcoinTestnet);
@@ -1646,6 +1803,8 @@ mod test {
                        InvoiceDescription::Hash(&Sha256(sha256::Hash::from_slice(&[3;32][..]).unwrap()))
                );
                assert_eq!(invoice.payment_hash(), &sha256::Hash::from_slice(&[21;32][..]).unwrap());
+               assert_eq!(invoice.payment_secret(), Some(&PaymentSecret([42; 32])));
+               assert_eq!(invoice.features(), Some(&InvoiceFeatures::known()));
 
                let raw_invoice = builder.build_raw().unwrap();
                assert_eq!(raw_invoice, *invoice.into_signed_raw().raw_invoice())