f - check offer expiry

Author: jkczyz

lightning/src/offers/invoice_request.rs

@@ -140,6 +140,12 @@ impl<'a> InvoiceRequestBuilder<'a> {
 	/// Builds an unsigned [`InvoiceRequest`] after checking for valid semantics. It can be signed
 	/// by [`UnsignedInvoiceRequest::sign`].
 	pub fn build(mut self) -> Result<UnsignedInvoiceRequest<'a>, SemanticError> {
+		#[cfg(feature = "std")] {
+			if self.offer.is_expired() {
+				return Err(SemanticError::AlreadyExpired);
+			}
+		}
+
 		let chain = self.invoice_request.chain();
 		if !self.offer.supports_chain(chain) {
 			return Err(SemanticError::UnsupportedChain);

lightning/src/offers/parse.rs

@@ -123,6 +123,8 @@ pub enum ParseError {
 /// Error when interpreting a TLV stream as a specific type.
 #[derive(Debug, PartialEq)]
 pub enum SemanticError {
+	/// The current [`std::time::SystemTime`] is past the offer or invoice's expiration.
+	AlreadyExpired,
 	/// The provided chain hash does not correspond to a supported chain.
 	UnsupportedChain,
 	/// An amount was expected but was missing.