Refactor send_payment internals for retries

We want to reuse send_payment internal functions for retries,
so some need to now be parameterized by PaymentId to avoid
generating a new PaymentId on retry

Author: valentinewallace

lightning/src/ln/channelmanager.rs

@@ -1998,10 +1998,10 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 	/// bit set (either as required or as available). If multiple paths are present in the Route,
 	/// we assume the invoice had the basic_mpp feature set.
 	pub fn send_payment(&self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>) -> Result<PaymentId, PaymentSendFailure> {
-		self.send_payment_internal(route, payment_hash, payment_secret, None)
+		self.send_payment_internal(route, payment_hash, payment_secret, None, None)
 	}
 
-	fn send_payment_internal(&self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, keysend_preimage: Option<PaymentPreimage>) -> Result<PaymentId, PaymentSendFailure> {
+	fn send_payment_internal(&self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, keysend_preimage: Option<PaymentPreimage>, payment_id: Option<PaymentId>) -> Result<PaymentId, PaymentSendFailure> {
 		if route.paths.len() < 1 {
 			return Err(PaymentSendFailure::ParameterError(APIError::RouteError{err: "There must be at least one path to send over"}));
 		}
@@ -2017,7 +2017,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 		let mut total_value = 0;
 		let our_node_id = self.get_our_node_id();
 		let mut path_errs = Vec::with_capacity(route.paths.len());
-		let payment_id = PaymentId(self.keys_manager.get_secure_random_bytes());
+		let payment_id = if let Some(id) = payment_id { id } else { PaymentId(self.keys_manager.get_secure_random_bytes()) };
 		'path_check: for path in route.paths.iter() {
 			if path.len() < 1 || path.len() > 20 {
 				path_errs.push(Err(APIError::RouteError{err: "Path didn't go anywhere/had bogus size"}));
@@ -2083,7 +2083,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 			None => PaymentPreimage(self.keys_manager.get_secure_random_bytes()),
 		};
 		let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
-		match self.send_payment_internal(route, payment_hash, &None, Some(preimage)) {
+		match self.send_payment_internal(route, payment_hash, &None, Some(preimage), None) {
 			Ok(payment_id) => Ok((payment_hash, payment_id)),
 			Err(e) => Err(e)
 		}
@@ -5936,7 +5936,7 @@ mod tests {
 
 		let test_preimage = PaymentPreimage([42; 32]);
 		let mismatch_payment_hash = PaymentHash([43; 32]);
-		let _ = nodes[0].node.send_payment_internal(&route, mismatch_payment_hash, &None, Some(test_preimage)).unwrap();
+		let _ = nodes[0].node.send_payment_internal(&route, mismatch_payment_hash, &None, Some(test_preimage), None).unwrap();
 		check_added_monitors!(nodes[0], 1);
 
 		let updates = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
@@ -5973,7 +5973,7 @@ mod tests {
 		let test_preimage = PaymentPreimage([42; 32]);
 		let test_secret = PaymentSecret([43; 32]);
 		let payment_hash = PaymentHash(Sha256::hash(&test_preimage.0).into_inner());
-		let _ = nodes[0].node.send_payment_internal(&route, payment_hash, &Some(test_secret), Some(test_preimage)).unwrap();
+		let _ = nodes[0].node.send_payment_internal(&route, payment_hash, &Some(test_secret), Some(test_preimage), None).unwrap();
 		check_added_monitors!(nodes[0], 1);
 
 		let updates = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());