Upgrade rust-bitcoin to 0.31
[rust-lightning] / lightning / src / offers / refund.rs
index 0a95f72511821f33c7b58214e1dcbe4cf2a5647b..d796971f8b366f721174895a643b6f6d2cb67ecc 100644 (file)
@@ -28,8 +28,8 @@
 //! use core::convert::TryFrom;
 //! use core::time::Duration;
 //!
-//! use bitcoin::network::constants::Network;
-//! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
+//! use bitcoin::network::Network;
+//! use bitcoin::secp256k1::{Keypair, PublicKey, Secp256k1, SecretKey};
 //! use lightning::offers::parse::Bolt12ParseError;
 //! use lightning::offers::refund::{Refund, RefundBuilder};
 //! use lightning::util::ser::{Readable, Writeable};
 //! # #[cfg(feature = "std")]
 //! # fn build() -> Result<(), Bolt12ParseError> {
 //! let secp_ctx = Secp256k1::new();
-//! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+//! let keys = Keypair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
 //! let pubkey = PublicKey::from(keys);
 //!
 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
-//! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
+//! let refund = RefundBuilder::new(vec![1; 32], pubkey, 20_000)?
+//!     .description("coffee, large".to_string())
 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
 //!     .issuer("Foo Bar".to_string())
 //!     .path(create_blinded_path())
 //! [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
 
 use bitcoin::blockdata::constants::ChainHash;
-use bitcoin::network::constants::Network;
+use bitcoin::network::Network;
 use bitcoin::secp256k1::{PublicKey, Secp256k1, self};
-use core::convert::TryFrom;
+use core::hash::{Hash, Hasher};
 use core::ops::Deref;
 use core::str::FromStr;
 use core::time::Duration;
 use crate::sign::EntropySource;
 use crate::io;
 use crate::blinded_path::BlindedPath;
-use crate::ln::PaymentHash;
+use crate::ln::types::PaymentHash;
 use crate::ln::channelmanager::PaymentId;
 use crate::ln::features::InvoiceRequestFeatures;
 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
-use crate::offers::invoice::{BlindedPayInfo, DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder};
+use crate::offers::invoice::BlindedPayInfo;
 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
@@ -105,6 +106,16 @@ use crate::offers::signer::{Metadata, MetadataMaterial, self};
 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
 use crate::util::string::PrintableString;
 
+#[cfg(not(c_bindings))]
+use {
+       crate::offers::invoice::{DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder},
+};
+#[cfg(c_bindings)]
+use {
+       crate::offers::invoice::{InvoiceWithDerivedSigningPubkeyBuilder, InvoiceWithExplicitSigningPubkeyBuilder},
+};
+
+#[allow(unused_imports)]
 use crate::prelude::*;
 
 #[cfg(feature = "std")]
@@ -124,12 +135,24 @@ pub struct RefundBuilder<'a, T: secp256k1::Signing> {
        secp_ctx: Option<&'a Secp256k1<T>>,
 }
 
-impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
+/// Builds a [`Refund`] for the "offer for money" flow.
+///
+/// See [module-level documentation] for usage.
+///
+/// [module-level documentation]: self
+#[cfg(c_bindings)]
+#[derive(Clone)]
+pub struct RefundMaybeWithDerivedMetadataBuilder<'a> {
+       refund: RefundContents,
+       secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
+}
+
+macro_rules! refund_explicit_metadata_builder_methods { () => {
        /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
        /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
        ///
-       /// Additionally, sets the required [`Refund::description`], [`Refund::payer_metadata`], and
-       /// [`Refund::amount_msats`].
+       /// Additionally, sets the required (empty) [`Refund::description`], [`Refund::payer_metadata`],
+       /// and [`Refund::amount_msats`].
        ///
        /// # Note
        ///
@@ -139,7 +162,7 @@ impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
        /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
        /// [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
        pub fn new(
-               description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
+               metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
        ) -> Result<Self, Bolt12SemanticError> {
                if amount_msats > MAX_VALUE_MSAT {
                        return Err(Bolt12SemanticError::InvalidAmount);
@@ -148,16 +171,18 @@ impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
                let metadata = Metadata::Bytes(metadata);
                Ok(Self {
                        refund: RefundContents {
-                               payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
-                               paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
-                               quantity: None, payer_id, payer_note: None,
+                               payer: PayerContents(metadata), description: String::new(), absolute_expiry: None,
+                               issuer: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
+                               quantity: None, payer_id, payer_note: None, paths: None,
                        },
                        secp_ctx: None,
                })
        }
-}
+} }
 
-impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
+macro_rules! refund_builder_methods { (
+       $self: ident, $self_type: ty, $return_type: ty, $return_value: expr, $secp_context: ty $(, $self_mut: tt)?
+) => {
        /// Similar to [`RefundBuilder::new`] except, if [`RefundBuilder::path`] is called, the payer id
        /// is derived from the given [`ExpandedKey`] and nonce. This provides sender privacy by using a
        /// different payer id for each refund, assuming a different nonce is used.  Otherwise, the
@@ -172,8 +197,8 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
        /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
        /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
        pub fn deriving_payer_id<ES: Deref>(
-               description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
-               secp_ctx: &'a Secp256k1<T>, amount_msats: u64, payment_id: PaymentId
+               node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
+               secp_ctx: &'a Secp256k1<$secp_context>, amount_msats: u64, payment_id: PaymentId
        ) -> Result<Self, Bolt12SemanticError> where ES::Target: EntropySource {
                if amount_msats > MAX_VALUE_MSAT {
                        return Err(Bolt12SemanticError::InvalidAmount);
@@ -185,29 +210,37 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
                let metadata = Metadata::DerivedSigningPubkey(derivation_material);
                Ok(Self {
                        refund: RefundContents {
-                               payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
-                               paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
-                               quantity: None, payer_id: node_id, payer_note: None,
+                               payer: PayerContents(metadata), description: String::new(), absolute_expiry: None,
+                               issuer: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
+                               quantity: None, payer_id: node_id, payer_note: None, paths: None,
                        },
                        secp_ctx: Some(secp_ctx),
                })
        }
 
+       /// Sets the [`Refund::description`].
+       ///
+       /// Successive calls to this method will override the previous setting.
+       pub fn description($($self_mut)* $self: $self_type, description: String) -> $return_type {
+               $self.refund.description = description;
+               $return_value
+       }
+
        /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
        /// already passed is valid and can be checked for using [`Refund::is_expired`].
        ///
        /// Successive calls to this method will override the previous setting.
-       pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
-               self.refund.absolute_expiry = Some(absolute_expiry);
-               self
+       pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
+               $self.refund.absolute_expiry = Some(absolute_expiry);
+               $return_value
        }
 
        /// Sets the [`Refund::issuer`].
        ///
        /// Successive calls to this method will override the previous setting.
-       pub fn issuer(mut self, issuer: String) -> Self {
-               self.refund.issuer = Some(issuer);
-               self
+       pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
+               $self.refund.issuer = Some(issuer);
+               $return_value
        }
 
        /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
@@ -215,26 +248,26 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
        ///
        /// Successive calls to this method will add another blinded path. Caller is responsible for not
        /// adding duplicate paths.
-       pub fn path(mut self, path: BlindedPath) -> Self {
-               self.refund.paths.get_or_insert_with(Vec::new).push(path);
-               self
+       pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
+               $self.refund.paths.get_or_insert_with(Vec::new).push(path);
+               $return_value
        }
 
        /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
        /// called, [`Network::Bitcoin`] is assumed.
        ///
        /// Successive calls to this method will override the previous setting.
-       pub fn chain(self, network: Network) -> Self {
-               self.chain_hash(ChainHash::using_genesis_block(network))
+       pub fn chain($self: $self_type, network: Network) -> $return_type {
+               $self.chain_hash(ChainHash::using_genesis_block(network))
        }
 
        /// Sets the [`Refund::chain`] of the given [`ChainHash`] for paying an invoice. If not called,
        /// [`Network::Bitcoin`] is assumed.
        ///
        /// Successive calls to this method will override the previous setting.
-       pub(crate) fn chain_hash(mut self, chain: ChainHash) -> Self {
-               self.refund.chain = Some(chain);
-               self
+       pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
+               $self.refund.chain = Some(chain);
+               $return_value
        }
 
        /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
@@ -246,60 +279,119 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
        /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
        /// [`Offer`]: crate::offers::offer::Offer
-       pub fn quantity(mut self, quantity: u64) -> Self {
-               self.refund.quantity = Some(quantity);
-               self
+       pub fn quantity($($self_mut)* $self: $self_type, quantity: u64) -> $return_type {
+               $self.refund.quantity = Some(quantity);
+               $return_value
        }
 
        /// Sets the [`Refund::payer_note`].
        ///
        /// Successive calls to this method will override the previous setting.
-       pub fn payer_note(mut self, payer_note: String) -> Self {
-               self.refund.payer_note = Some(payer_note);
-               self
+       pub fn payer_note($($self_mut)* $self: $self_type, payer_note: String) -> $return_type {
+               $self.refund.payer_note = Some(payer_note);
+               $return_value
        }
 
        /// Builds a [`Refund`] after checking for valid semantics.
-       pub fn build(mut self) -> Result<Refund, Bolt12SemanticError> {
-               if self.refund.chain() == self.refund.implied_chain() {
-                       self.refund.chain = None;
+       pub fn build($($self_mut)* $self: $self_type) -> Result<Refund, Bolt12SemanticError> {
+               if $self.refund.chain() == $self.refund.implied_chain() {
+                       $self.refund.chain = None;
                }
 
                // Create the metadata for stateless verification of a Bolt12Invoice.
-               if self.refund.payer.0.has_derivation_material() {
-                       let mut metadata = core::mem::take(&mut self.refund.payer.0);
+               if $self.refund.payer.0.has_derivation_material() {
+                       let mut metadata = core::mem::take(&mut $self.refund.payer.0);
 
-                       if self.refund.paths.is_none() {
+                       if $self.refund.paths.is_none() {
                                metadata = metadata.without_keys();
                        }
 
-                       let mut tlv_stream = self.refund.as_tlv_stream();
+                       let mut tlv_stream = $self.refund.as_tlv_stream();
                        tlv_stream.0.metadata = None;
                        if metadata.derives_payer_keys() {
                                tlv_stream.2.payer_id = None;
                        }
 
-                       let (derived_metadata, keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
+                       let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
                        metadata = derived_metadata;
                        if let Some(keys) = keys {
-                               self.refund.payer_id = keys.public_key();
+                               $self.refund.payer_id = keys.public_key();
                        }
 
-                       self.refund.payer.0 = metadata;
+                       $self.refund.payer.0 = metadata;
                }
 
                let mut bytes = Vec::new();
-               self.refund.write(&mut bytes).unwrap();
+               $self.refund.write(&mut bytes).unwrap();
+
+               Ok(Refund {
+                       bytes,
+                       #[cfg(not(c_bindings))]
+                       contents: $self.refund,
+                       #[cfg(c_bindings)]
+                       contents: $self.refund.clone(),
+               })
+       }
+} }
 
-               Ok(Refund { bytes, contents: self.refund })
+#[cfg(test)]
+macro_rules! refund_builder_test_methods { (
+       $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
+) => {
+       #[cfg_attr(c_bindings, allow(dead_code))]
+       pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
+               $self.refund.paths = None;
+               $return_value
+       }
+
+       #[cfg_attr(c_bindings, allow(dead_code))]
+       fn features_unchecked($($self_mut)* $self: $self_type, features: InvoiceRequestFeatures) -> $return_type {
+               $self.refund.features = features;
+               $return_value
        }
+} }
+
+impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
+       refund_explicit_metadata_builder_methods!();
 }
 
-#[cfg(test)]
 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
-       fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
-               self.refund.features = features;
-               self
+       refund_builder_methods!(self, Self, Self, self, T, mut);
+
+       #[cfg(test)]
+       refund_builder_test_methods!(self, Self, Self, self, mut);
+}
+
+#[cfg(all(c_bindings, not(test)))]
+impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
+       refund_explicit_metadata_builder_methods!();
+       refund_builder_methods!(self, &mut Self, (), (), secp256k1::All);
+}
+
+#[cfg(all(c_bindings, test))]
+impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
+       refund_explicit_metadata_builder_methods!();
+       refund_builder_methods!(self, &mut Self, &mut Self, self, secp256k1::All);
+       refund_builder_test_methods!(self, &mut Self, &mut Self, self);
+}
+
+#[cfg(c_bindings)]
+impl<'a> From<RefundBuilder<'a, secp256k1::All>>
+for RefundMaybeWithDerivedMetadataBuilder<'a> {
+       fn from(builder: RefundBuilder<'a, secp256k1::All>) -> Self {
+               let RefundBuilder { refund, secp_ctx } = builder;
+
+               Self { refund, secp_ctx }
+       }
+}
+
+#[cfg(c_bindings)]
+impl<'a> From<RefundMaybeWithDerivedMetadataBuilder<'a>>
+for RefundBuilder<'a, secp256k1::All> {
+       fn from(builder: RefundMaybeWithDerivedMetadataBuilder<'a>) -> Self {
+               let RefundMaybeWithDerivedMetadataBuilder { refund, secp_ctx } = builder;
+
+               Self { refund, secp_ctx }
        }
 }
 
@@ -312,7 +404,6 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 /// [`Offer`]: crate::offers::offer::Offer
 #[derive(Clone, Debug)]
-#[cfg_attr(test, derive(PartialEq))]
 pub struct Refund {
        pub(super) bytes: Vec<u8>,
        pub(super) contents: RefundContents,
@@ -329,7 +420,6 @@ pub(super) struct RefundContents {
        description: String,
        absolute_expiry: Option<Duration>,
        issuer: Option<String>,
-       paths: Option<Vec<BlindedPath>>,
        // invoice_request fields
        chain: Option<ChainHash>,
        amount_msats: u64,
@@ -337,6 +427,7 @@ pub(super) struct RefundContents {
        quantity: Option<u64>,
        payer_id: PublicKey,
        payer_note: Option<String>,
+       paths: Option<Vec<BlindedPath>>,
 }
 
 impl Refund {
@@ -359,6 +450,11 @@ impl Refund {
                self.contents.is_expired()
        }
 
+       /// Whether the refund has expired given the duration since the Unix epoch.
+       pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
+               self.contents.is_expired_no_std(duration_since_epoch)
+       }
+
        /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
        /// displayed to the user but with the caveat that it has not been verified in any way.
        pub fn issuer(&self) -> Option<PrintableString> {
@@ -413,7 +509,9 @@ impl Refund {
        pub fn payer_note(&self) -> Option<PrintableString> {
                self.contents.payer_note()
        }
+}
 
+macro_rules! respond_with_explicit_signing_pubkey_methods { ($self: ident, $builder: ty) => {
        /// Creates an [`InvoiceBuilder`] for the refund with the given required fields and using the
        /// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
        ///
@@ -425,14 +523,14 @@ impl Refund {
        /// [`Duration`]: core::time::Duration
        #[cfg(feature = "std")]
        pub fn respond_with(
-               &self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+               &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
                signing_pubkey: PublicKey,
-       ) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, Bolt12SemanticError> {
+       ) -> Result<$builder, Bolt12SemanticError> {
                let created_at = std::time::SystemTime::now()
                        .duration_since(std::time::SystemTime::UNIX_EPOCH)
                        .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 
-               self.respond_with_no_std(payment_paths, payment_hash, signing_pubkey, created_at)
+               $self.respond_with_no_std(payment_paths, payment_hash, signing_pubkey, created_at)
        }
 
        /// Creates an [`InvoiceBuilder`] for the refund with the given required fields.
@@ -458,16 +556,18 @@ impl Refund {
        ///
        /// [`Bolt12Invoice::created_at`]: crate::offers::invoice::Bolt12Invoice::created_at
        pub fn respond_with_no_std(
-               &self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+               &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
                signing_pubkey: PublicKey, created_at: Duration
-       ) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, Bolt12SemanticError> {
-               if self.features().requires_unknown_bits() {
+       ) -> Result<$builder, Bolt12SemanticError> {
+               if $self.features().requires_unknown_bits() {
                        return Err(Bolt12SemanticError::UnknownRequiredFeatures);
                }
 
-               InvoiceBuilder::for_refund(self, payment_paths, created_at, payment_hash, signing_pubkey)
+               <$builder>::for_refund($self, payment_paths, created_at, payment_hash, signing_pubkey)
        }
+} }
 
+macro_rules! respond_with_derived_signing_pubkey_methods { ($self: ident, $builder: ty) => {
        /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
        /// derived signing keys to sign the [`Bolt12Invoice`].
        ///
@@ -478,9 +578,9 @@ impl Refund {
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
        #[cfg(feature = "std")]
        pub fn respond_using_derived_keys<ES: Deref>(
-               &self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+               &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
                expanded_key: &ExpandedKey, entropy_source: ES
-       ) -> Result<InvoiceBuilder<DerivedSigningPubkey>, Bolt12SemanticError>
+       ) -> Result<$builder, Bolt12SemanticError>
        where
                ES::Target: EntropySource,
        {
@@ -488,7 +588,7 @@ impl Refund {
                        .duration_since(std::time::SystemTime::UNIX_EPOCH)
                        .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 
-               self.respond_using_derived_keys_no_std(
+               $self.respond_using_derived_keys_no_std(
                        payment_paths, payment_hash, created_at, expanded_key, entropy_source
                )
        }
@@ -502,22 +602,36 @@ impl Refund {
        ///
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
        pub fn respond_using_derived_keys_no_std<ES: Deref>(
-               &self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+               &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
                created_at: core::time::Duration, expanded_key: &ExpandedKey, entropy_source: ES
-       ) -> Result<InvoiceBuilder<DerivedSigningPubkey>, Bolt12SemanticError>
+       ) -> Result<$builder, Bolt12SemanticError>
        where
                ES::Target: EntropySource,
        {
-               if self.features().requires_unknown_bits() {
+               if $self.features().requires_unknown_bits() {
                        return Err(Bolt12SemanticError::UnknownRequiredFeatures);
                }
 
                let nonce = Nonce::from_entropy_source(entropy_source);
                let keys = signer::derive_keys(nonce, expanded_key);
-               InvoiceBuilder::for_refund_using_keys(self, payment_paths, created_at, payment_hash, keys)
+               <$builder>::for_refund_using_keys($self, payment_paths, created_at, payment_hash, keys)
        }
+} }
 
-       #[cfg(test)]
+#[cfg(not(c_bindings))]
+impl Refund {
+       respond_with_explicit_signing_pubkey_methods!(self, InvoiceBuilder<ExplicitSigningPubkey>);
+       respond_with_derived_signing_pubkey_methods!(self, InvoiceBuilder<DerivedSigningPubkey>);
+}
+
+#[cfg(c_bindings)]
+impl Refund {
+       respond_with_explicit_signing_pubkey_methods!(self, InvoiceWithExplicitSigningPubkeyBuilder);
+       respond_with_derived_signing_pubkey_methods!(self, InvoiceWithDerivedSigningPubkeyBuilder);
+}
+
+#[cfg(test)]
+impl Refund {
        fn as_tlv_stream(&self) -> RefundTlvStreamRef {
                self.contents.as_tlv_stream()
        }
@@ -529,6 +643,20 @@ impl AsRef<[u8]> for Refund {
        }
 }
 
+impl PartialEq for Refund {
+       fn eq(&self, other: &Self) -> bool {
+               self.bytes.eq(&other.bytes)
+       }
+}
+
+impl Eq for Refund {}
+
+impl Hash for Refund {
+       fn hash<H: Hasher>(&self, state: &mut H) {
+               self.bytes.hash(state);
+       }
+}
+
 impl RefundContents {
        pub fn description(&self) -> PrintableString {
                PrintableString(&self.description)
@@ -616,7 +744,7 @@ impl RefundContents {
                        description: Some(&self.description),
                        features: None,
                        absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
-                       paths: self.paths.as_ref(),
+                       paths: None,
                        issuer: self.issuer.as_ref(),
                        quantity_max: None,
                        node_id: None,
@@ -634,6 +762,7 @@ impl RefundContents {
                        quantity: self.quantity,
                        payer_id: Some(&self.payer_id),
                        payer_note: self.payer_note.as_ref(),
+                       paths: self.paths.as_ref(),
                };
 
                (payer, offer, invoice_request)
@@ -702,9 +831,12 @@ impl TryFrom<RefundTlvStream> for RefundContents {
                        PayerTlvStream { metadata: payer_metadata },
                        OfferTlvStream {
                                chains, metadata, currency, amount: offer_amount, description,
-                               features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
+                               features: offer_features, absolute_expiry, paths: offer_paths, issuer, quantity_max,
+                               node_id,
+                       },
+                       InvoiceRequestTlvStream {
+                               chain, amount, features, quantity, payer_id, payer_note, paths
                        },
-                       InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
                ) = tlv_stream;
 
                let payer = match payer_metadata {
@@ -735,6 +867,10 @@ impl TryFrom<RefundTlvStream> for RefundContents {
 
                let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 
+               if offer_paths.is_some() {
+                       return Err(Bolt12SemanticError::UnexpectedPaths);
+               }
+
                if quantity_max.is_some() {
                        return Err(Bolt12SemanticError::UnexpectedQuantity);
                }
@@ -759,8 +895,8 @@ impl TryFrom<RefundTlvStream> for RefundContents {
                };
 
                Ok(RefundContents {
-                       payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
-                       quantity, payer_id, payer_note,
+                       payer, description, absolute_expiry, issuer, chain, amount_msats, features, quantity,
+                       payer_id, payer_note, paths,
                })
        }
 }
@@ -773,14 +909,23 @@ impl core::fmt::Display for Refund {
 
 #[cfg(test)]
 mod tests {
-       use super::{Refund, RefundBuilder, RefundTlvStreamRef};
+       use super::{Refund, RefundTlvStreamRef};
+       #[cfg(not(c_bindings))]
+       use {
+               super::RefundBuilder,
+       };
+       #[cfg(c_bindings)]
+       use {
+               super::RefundMaybeWithDerivedMetadataBuilder as RefundBuilder,
+       };
 
        use bitcoin::blockdata::constants::ChainHash;
-       use bitcoin::network::constants::Network;
-       use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
-       use core::convert::TryFrom;
+       use bitcoin::network::Network;
+       use bitcoin::secp256k1::{Keypair, Secp256k1, SecretKey};
+
        use core::time::Duration;
-       use crate::blinded_path::{BlindedHop, BlindedPath};
+
+       use crate::blinded_path::{BlindedHop, BlindedPath, IntroductionNode};
        use crate::sign::KeyMaterial;
        use crate::ln::channelmanager::PaymentId;
        use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
@@ -793,6 +938,7 @@ mod tests {
        use crate::offers::test_utils::*;
        use crate::util::ser::{BigSize, Writeable};
        use crate::util::string::PrintableString;
+       use crate::prelude::*;
 
        trait ToBytes {
                fn to_bytes(&self) -> Vec<u8>;
@@ -808,7 +954,7 @@ mod tests {
 
        #[test]
        fn builds_refund_with_defaults() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .build().unwrap();
 
                let mut buffer = Vec::new();
@@ -816,7 +962,7 @@ mod tests {
 
                assert_eq!(refund.bytes, buffer.as_slice());
                assert_eq!(refund.payer_metadata(), &[1; 32]);
-               assert_eq!(refund.description(), PrintableString("foo"));
+               assert_eq!(refund.description(), PrintableString(""));
                assert_eq!(refund.absolute_expiry(), None);
                #[cfg(feature = "std")]
                assert!(!refund.is_expired());
@@ -837,7 +983,7 @@ mod tests {
                                        metadata: None,
                                        currency: None,
                                        amount: None,
-                                       description: Some(&String::from("foo")),
+                                       description: Some(&String::from("")),
                                        features: None,
                                        absolute_expiry: None,
                                        paths: None,
@@ -852,6 +998,7 @@ mod tests {
                                        quantity: None,
                                        payer_id: Some(&payer_pubkey()),
                                        payer_note: None,
+                                       paths: None,
                                },
                        ),
                );
@@ -863,7 +1010,7 @@ mod tests {
 
        #[test]
        fn fails_building_refund_with_invalid_amount() {
-               match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
+               match RefundBuilder::new(vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
                        Ok(_) => panic!("expected error"),
                        Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
                }
@@ -871,7 +1018,6 @@ mod tests {
 
        #[test]
        fn builds_refund_with_metadata_derived() {
-               let desc = "foo".to_string();
                let node_id = payer_pubkey();
                let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
                let entropy = FixedEntropy {};
@@ -879,7 +1025,7 @@ mod tests {
                let payment_id = PaymentId([1; 32]);
 
                let refund = RefundBuilder
-                       ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
+                       ::deriving_payer_id(node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
                        .unwrap()
                        .build().unwrap();
                assert_eq!(refund.payer_id(), node_id);
@@ -926,7 +1072,6 @@ mod tests {
 
        #[test]
        fn builds_refund_with_derived_payer_id() {
-               let desc = "foo".to_string();
                let node_id = payer_pubkey();
                let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
                let entropy = FixedEntropy {};
@@ -934,7 +1079,7 @@ mod tests {
                let payment_id = PaymentId([1; 32]);
 
                let blinded_path = BlindedPath {
-                       introduction_node_id: pubkey(40),
+                       introduction_node: IntroductionNode::NodeId(pubkey(40)),
                        blinding_point: pubkey(41),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
@@ -943,7 +1088,7 @@ mod tests {
                };
 
                let refund = RefundBuilder
-                       ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
+                       ::deriving_payer_id(node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
                        .unwrap()
                        .path(blinded_path)
                        .build().unwrap();
@@ -993,18 +1138,20 @@ mod tests {
        fn builds_refund_with_absolute_expiry() {
                let future_expiry = Duration::from_secs(u64::max_value());
                let past_expiry = Duration::from_secs(0);
+               let now = future_expiry - Duration::from_secs(1_000);
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .absolute_expiry(future_expiry)
                        .build()
                        .unwrap();
                let (_, tlv_stream, _) = refund.as_tlv_stream();
                #[cfg(feature = "std")]
                assert!(!refund.is_expired());
+               assert!(!refund.is_expired_no_std(now));
                assert_eq!(refund.absolute_expiry(), Some(future_expiry));
                assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .absolute_expiry(future_expiry)
                        .absolute_expiry(past_expiry)
                        .build()
@@ -1012,6 +1159,7 @@ mod tests {
                let (_, tlv_stream, _) = refund.as_tlv_stream();
                #[cfg(feature = "std")]
                assert!(refund.is_expired());
+               assert!(refund.is_expired_no_std(now));
                assert_eq!(refund.absolute_expiry(), Some(past_expiry));
                assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
        }
@@ -1020,7 +1168,7 @@ mod tests {
        fn builds_refund_with_paths() {
                let paths = vec![
                        BlindedPath {
-                               introduction_node_id: pubkey(40),
+                               introduction_node: IntroductionNode::NodeId(pubkey(40)),
                                blinding_point: pubkey(41),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
@@ -1028,7 +1176,7 @@ mod tests {
                                ],
                        },
                        BlindedPath {
-                               introduction_node_id: pubkey(40),
+                               introduction_node: IntroductionNode::NodeId(pubkey(40)),
                                blinding_point: pubkey(41),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
@@ -1037,22 +1185,22 @@ mod tests {
                        },
                ];
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .path(paths[0].clone())
                        .path(paths[1].clone())
                        .build()
                        .unwrap();
-               let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
-               assert_eq!(refund.paths(), paths.as_slice());
+               let (_, _, invoice_request_tlv_stream) = refund.as_tlv_stream();
                assert_eq!(refund.payer_id(), pubkey(42));
+               assert_eq!(refund.paths(), paths.as_slice());
                assert_ne!(pubkey(42), pubkey(44));
-               assert_eq!(offer_tlv_stream.paths, Some(&paths));
                assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
+               assert_eq!(invoice_request_tlv_stream.paths, Some(&paths));
        }
 
        #[test]
        fn builds_refund_with_issuer() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .issuer("bar".into())
                        .build()
                        .unwrap();
@@ -1060,7 +1208,7 @@ mod tests {
                assert_eq!(refund.issuer(), Some(PrintableString("bar")));
                assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .issuer("bar".into())
                        .issuer("baz".into())
                        .build()
@@ -1075,21 +1223,21 @@ mod tests {
                let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
                let testnet = ChainHash::using_genesis_block(Network::Testnet);
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .chain(Network::Bitcoin)
                        .build().unwrap();
                let (_, _, tlv_stream) = refund.as_tlv_stream();
                assert_eq!(refund.chain(), mainnet);
                assert_eq!(tlv_stream.chain, None);
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .chain(Network::Testnet)
                        .build().unwrap();
                let (_, _, tlv_stream) = refund.as_tlv_stream();
                assert_eq!(refund.chain(), testnet);
                assert_eq!(tlv_stream.chain, Some(&testnet));
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .chain(Network::Regtest)
                        .chain(Network::Testnet)
                        .build().unwrap();
@@ -1100,14 +1248,14 @@ mod tests {
 
        #[test]
        fn builds_refund_with_quantity() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .quantity(10)
                        .build().unwrap();
                let (_, _, tlv_stream) = refund.as_tlv_stream();
                assert_eq!(refund.quantity(), Some(10));
                assert_eq!(tlv_stream.quantity, Some(10));
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .quantity(10)
                        .quantity(1)
                        .build().unwrap();
@@ -1118,14 +1266,14 @@ mod tests {
 
        #[test]
        fn builds_refund_with_payer_note() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .payer_note("bar".into())
                        .build().unwrap();
                let (_, _, tlv_stream) = refund.as_tlv_stream();
                assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
                assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .payer_note("bar".into())
                        .payer_note("baz".into())
                        .build().unwrap();
@@ -1136,7 +1284,7 @@ mod tests {
 
        #[test]
        fn fails_responding_with_unknown_required_features() {
-               match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               match RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .features_unchecked(InvoiceRequestFeatures::unknown())
                        .build().unwrap()
                        .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
@@ -1148,7 +1296,7 @@ mod tests {
 
        #[test]
        fn parses_refund_with_metadata() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .build().unwrap();
                if let Err(e) = refund.to_string().parse::<Refund>() {
                        panic!("error parsing refund: {:?}", e);
@@ -1167,7 +1315,7 @@ mod tests {
 
        #[test]
        fn parses_refund_with_description() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .build().unwrap();
                if let Err(e) = refund.to_string().parse::<Refund>() {
                        panic!("error parsing refund: {:?}", e);
@@ -1186,7 +1334,7 @@ mod tests {
 
        #[test]
        fn parses_refund_with_amount() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .build().unwrap();
                if let Err(e) = refund.to_string().parse::<Refund>() {
                        panic!("error parsing refund: {:?}", e);
@@ -1215,7 +1363,7 @@ mod tests {
 
        #[test]
        fn parses_refund_with_payer_id() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .build().unwrap();
                if let Err(e) = refund.to_string().parse::<Refund>() {
                        panic!("error parsing refund: {:?}", e);
@@ -1237,7 +1385,7 @@ mod tests {
                let past_expiry = Duration::from_secs(0);
                let paths = vec![
                        BlindedPath {
-                               introduction_node_id: pubkey(40),
+                               introduction_node: IntroductionNode::NodeId(pubkey(40)),
                                blinding_point: pubkey(41),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
@@ -1245,7 +1393,7 @@ mod tests {
                                ],
                        },
                        BlindedPath {
-                               introduction_node_id: pubkey(40),
+                               introduction_node: IntroductionNode::NodeId(pubkey(40)),
                                blinding_point: pubkey(41),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
@@ -1254,7 +1402,7 @@ mod tests {
                        },
                ];
 
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .absolute_expiry(past_expiry)
                        .issuer("bar".into())
                        .path(paths[0].clone())
@@ -1283,7 +1431,7 @@ mod tests {
 
        #[test]
        fn fails_parsing_refund_with_unexpected_fields() {
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+               let refund = RefundBuilder::new(vec![1; 32], payer_pubkey(), 1000).unwrap()
                        .build().unwrap();
                if let Err(e) = refund.to_string().parse::<Refund>() {
                        panic!("error parsing refund: {:?}", e);
@@ -1358,8 +1506,8 @@ mod tests {
        #[test]
        fn fails_parsing_refund_with_extra_tlv_records() {
                let secp_ctx = Secp256k1::new();
-               let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
-               let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
+               let keys = Keypair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+               let refund = RefundBuilder::new(vec![1; 32], keys.public_key(), 1000).unwrap()
                        .build().unwrap();
 
                let mut encoded_refund = Vec::new();