Implement `Hash` for `Offer` and `Refund`
[rust-lightning] / lightning / src / offers / refund.rs
index 2c8dffeb1516abfa7961d144581d412657861c2a..5107e31d8d0a07e6527d7838d7a19439c86e54c1 100644 (file)
@@ -18,6 +18,8 @@
 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 //! [`Offer`]: crate::offers::offer::Offer
 //!
+//! # Example
+//!
 //! ```
 //! extern crate bitcoin;
 //! extern crate core;
 //! # Ok(())
 //! # }
 //! ```
+//!
+//! # Note
+//!
+//! If constructing a [`Refund`] for use with a [`ChannelManager`], use
+//! [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
+//!
+//! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+//! [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
 
 use bitcoin::blockdata::constants::ChainHash;
 use bitcoin::network::constants::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;
@@ -82,6 +93,7 @@ use crate::sign::EntropySource;
 use crate::io;
 use crate::blinded_path::BlindedPath;
 use crate::ln::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};
@@ -117,8 +129,16 @@ impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
        /// 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::metadata`], and
+       /// Additionally, sets the required [`Refund::description`], [`Refund::payer_metadata`], and
        /// [`Refund::amount_msats`].
+       ///
+       /// # Note
+       ///
+       /// If constructing a [`Refund`] for use with a [`ChannelManager`], use
+       /// [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
+       ///
+       /// [`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
        ) -> Result<Self, Bolt12SemanticError> {
@@ -147,18 +167,22 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
        /// Also, sets the metadata when [`RefundBuilder::build`] is called such that it can be used to
        /// verify that an [`InvoiceRequest`] was produced for the refund given an [`ExpandedKey`].
        ///
+       /// The `payment_id` is encrypted in the metadata and should be unique. This ensures that only
+       /// one invoice will be paid for the refund and that payments can be uniquely identified.
+       ///
        /// [`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
+               secp_ctx: &'a Secp256k1<T>, amount_msats: u64, payment_id: PaymentId
        ) -> Result<Self, Bolt12SemanticError> where ES::Target: EntropySource {
                if amount_msats > MAX_VALUE_MSAT {
                        return Err(Bolt12SemanticError::InvalidAmount);
                }
 
                let nonce = Nonce::from_entropy_source(entropy_source);
-               let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES);
+               let payment_id = Some(payment_id);
+               let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, payment_id);
                let metadata = Metadata::DerivedSigningPubkey(derivation_material);
                Ok(Self {
                        refund: RefundContents {
@@ -201,8 +225,16 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
        /// called, [`Network::Bitcoin`] is assumed.
        ///
        /// Successive calls to this method will override the previous setting.
-       pub fn chain(mut self, network: Network) -> Self {
-               self.refund.chain = Some(ChainHash::using_genesis_block(network));
+       pub fn chain(self, network: Network) -> Self {
+               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
        }
 
@@ -244,7 +276,7 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
 
                        let mut tlv_stream = self.refund.as_tlv_stream();
                        tlv_stream.0.metadata = None;
-                       if metadata.derives_keys() {
+                       if metadata.derives_payer_keys() {
                                tlv_stream.2.payer_id = None;
                        }
 
@@ -266,6 +298,11 @@ impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
 
 #[cfg(test)]
 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
+       pub(crate) fn clear_paths(mut self) -> Self {
+               self.refund.paths = None;
+               self
+       }
+
        fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
                self.refund.features = features;
                self
@@ -281,7 +318,6 @@ 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,
@@ -319,7 +355,7 @@ impl Refund {
        ///
        /// If `None`, the refund does not expire.
        pub fn absolute_expiry(&self) -> Option<Duration> {
-               self.contents.absolute_expiry
+               self.contents.absolute_expiry()
        }
 
        /// Whether the refund has expired.
@@ -328,46 +364,51 @@ 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> {
-               self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
+               self.contents.issuer()
        }
 
        /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
        /// privacy by obfuscating its node id.
        pub fn paths(&self) -> &[BlindedPath] {
-               self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
+               self.contents.paths()
        }
 
        /// An unpredictable series of bytes, typically containing information about the derivation of
        /// [`payer_id`].
        ///
        /// [`payer_id`]: Self::payer_id
-       pub fn metadata(&self) -> &[u8] {
+       pub fn payer_metadata(&self) -> &[u8] {
                self.contents.metadata()
        }
 
        /// A chain that the refund is valid for.
        pub fn chain(&self) -> ChainHash {
-               self.contents.chain.unwrap_or_else(|| self.contents.implied_chain())
+               self.contents.chain()
        }
 
        /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
        ///
        /// [`chain`]: Self::chain
        pub fn amount_msats(&self) -> u64 {
-               self.contents.amount_msats
+               self.contents.amount_msats()
        }
 
        /// Features pertaining to requesting an invoice.
        pub fn features(&self) -> &InvoiceRequestFeatures {
-               &self.contents.features
+               &self.contents.features()
        }
 
        /// The quantity of an item that refund is for.
        pub fn quantity(&self) -> Option<u64> {
-               self.contents.quantity
+               self.contents.quantity()
        }
 
        /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
@@ -375,12 +416,12 @@ impl Refund {
        ///
        /// [`paths`]: Self::paths
        pub fn payer_id(&self) -> PublicKey {
-               self.contents.payer_id
+               self.contents.payer_id()
        }
 
        /// Payer provided note to include in the invoice.
        pub fn payer_note(&self) -> Option<PrintableString> {
-               self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
+               self.contents.payer_note()
        }
 
        /// Creates an [`InvoiceBuilder`] for the refund with the given required fields and using the
@@ -498,20 +539,49 @@ 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)
        }
 
+       pub fn absolute_expiry(&self) -> Option<Duration> {
+               self.absolute_expiry
+       }
+
        #[cfg(feature = "std")]
        pub(super) fn is_expired(&self) -> bool {
-               match self.absolute_expiry {
-                       Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
-                               Ok(elapsed) => elapsed > seconds_from_epoch,
-                               Err(_) => false,
-                       },
-                       None => false,
-               }
+               SystemTime::UNIX_EPOCH
+                       .elapsed()
+                       .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
+                       .unwrap_or(false)
+       }
+
+       pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
+               self.absolute_expiry
+                       .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
+                       .unwrap_or(false)
+       }
+
+       pub fn issuer(&self) -> Option<PrintableString> {
+               self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
+       }
+
+       pub fn paths(&self) -> &[BlindedPath] {
+               self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
        }
 
        pub(super) fn metadata(&self) -> &[u8] {
@@ -526,14 +596,37 @@ impl RefundContents {
                ChainHash::using_genesis_block(Network::Bitcoin)
        }
 
-       pub(super) fn derives_keys(&self) -> bool {
-               self.payer.0.derives_keys()
+       pub fn amount_msats(&self) -> u64 {
+               self.amount_msats
+       }
+
+       /// Features pertaining to requesting an invoice.
+       pub fn features(&self) -> &InvoiceRequestFeatures {
+               &self.features
        }
 
-       pub(super) fn payer_id(&self) -> PublicKey {
+       /// The quantity of an item that refund is for.
+       pub fn quantity(&self) -> Option<u64> {
+               self.quantity
+       }
+
+       /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
+       /// transient pubkey.
+       ///
+       /// [`paths`]: Self::paths
+       pub fn payer_id(&self) -> PublicKey {
                self.payer_id
        }
 
+       /// Payer provided note to include in the invoice.
+       pub fn payer_note(&self) -> Option<PrintableString> {
+               self.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
+       }
+
+       pub(super) fn derives_keys(&self) -> bool {
+               self.payer.0.derives_payer_keys()
+       }
+
        pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
                let payer = PayerTlvStreamRef {
                        metadata: self.payer.0.as_bytes(),
@@ -713,6 +806,7 @@ mod tests {
        use core::time::Duration;
        use crate::blinded_path::{BlindedHop, BlindedPath};
        use crate::sign::KeyMaterial;
+       use crate::ln::channelmanager::PaymentId;
        use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
        use crate::ln::inbound_payment::ExpandedKey;
        use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
@@ -745,7 +839,7 @@ mod tests {
                refund.write(&mut buffer).unwrap();
 
                assert_eq!(refund.bytes, buffer.as_slice());
-               assert_eq!(refund.metadata(), &[1; 32]);
+               assert_eq!(refund.payer_metadata(), &[1; 32]);
                assert_eq!(refund.description(), PrintableString("foo"));
                assert_eq!(refund.absolute_expiry(), None);
                #[cfg(feature = "std")]
@@ -806,9 +900,10 @@ mod tests {
                let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
                let entropy = FixedEntropy {};
                let secp_ctx = Secp256k1::new();
+               let payment_id = PaymentId([1; 32]);
 
                let refund = RefundBuilder
-                       ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000)
+                       ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
                        .unwrap()
                        .build().unwrap();
                assert_eq!(refund.payer_id(), node_id);
@@ -819,7 +914,10 @@ mod tests {
                        .unwrap()
                        .build().unwrap()
                        .sign(recipient_sign).unwrap();
-               assert!(invoice.verify(&expanded_key, &secp_ctx));
+               match invoice.verify(&expanded_key, &secp_ctx) {
+                       Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
+                       Err(()) => panic!("verification failed"),
+               }
 
                let mut tlv_stream = refund.as_tlv_stream();
                tlv_stream.2.amount = Some(2000);
@@ -832,7 +930,7 @@ mod tests {
                        .unwrap()
                        .build().unwrap()
                        .sign(recipient_sign).unwrap();
-               assert!(!invoice.verify(&expanded_key, &secp_ctx));
+               assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 
                // Fails verification with altered metadata
                let mut tlv_stream = refund.as_tlv_stream();
@@ -847,7 +945,7 @@ mod tests {
                        .unwrap()
                        .build().unwrap()
                        .sign(recipient_sign).unwrap();
-               assert!(!invoice.verify(&expanded_key, &secp_ctx));
+               assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
        }
 
        #[test]
@@ -857,6 +955,7 @@ mod tests {
                let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
                let entropy = FixedEntropy {};
                let secp_ctx = Secp256k1::new();
+               let payment_id = PaymentId([1; 32]);
 
                let blinded_path = BlindedPath {
                        introduction_node_id: pubkey(40),
@@ -868,7 +967,7 @@ mod tests {
                };
 
                let refund = RefundBuilder
-                       ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000)
+                       ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
                        .unwrap()
                        .path(blinded_path)
                        .build().unwrap();
@@ -879,7 +978,10 @@ mod tests {
                        .unwrap()
                        .build().unwrap()
                        .sign(recipient_sign).unwrap();
-               assert!(invoice.verify(&expanded_key, &secp_ctx));
+               match invoice.verify(&expanded_key, &secp_ctx) {
+                       Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
+                       Err(()) => panic!("verification failed"),
+               }
 
                // Fails verification with altered fields
                let mut tlv_stream = refund.as_tlv_stream();
@@ -893,7 +995,7 @@ mod tests {
                        .unwrap()
                        .build().unwrap()
                        .sign(recipient_sign).unwrap();
-               assert!(!invoice.verify(&expanded_key, &secp_ctx));
+               assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 
                // Fails verification with altered payer_id
                let mut tlv_stream = refund.as_tlv_stream();
@@ -908,13 +1010,14 @@ mod tests {
                        .unwrap()
                        .build().unwrap()
                        .sign(recipient_sign).unwrap();
-               assert!(!invoice.verify(&expanded_key, &secp_ctx));
+               assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
        }
 
        #[test]
        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()
                        .absolute_expiry(future_expiry)
@@ -923,6 +1026,7 @@ 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(future_expiry));
                assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
 
@@ -934,6 +1038,7 @@ 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()));
        }