ln: add incoming_accountable to PendingHTLCInfo

Persist as a bool so that we don't need to use Option<bool> when we
will just inevitably unwrap_or(false) the field. This means that we
won't be able to distinguish between an incoming htlc that has no TLV
set, and one that has the TLV set with a false value in it. We accept
this loss of information for the sake of simplicity in the codebase.

Author: carlaKC

lightning/src/ln/channelmanager.rs

@@ -427,6 +427,9 @@ pub struct PendingHTLCInfo {
 	/// This is used to allow LSPs to take fees as a part of payments, without the sender having to
 	/// shoulder them.
 	pub skimmed_fee_msat: Option<u64>,
+	/// An experimental field indicating whether our node's reputation would be held accountable
+	/// for the timely resolution of the received HTLC.
+	pub incoming_accountable: bool,
 }
 
 #[derive(Clone, Debug)] // See FundedChannel::revoke_and_ack for why, tl;dr: Rust bug
@@ -5249,7 +5252,7 @@ where
 				let current_height: u32 = self.best_block.read().unwrap().height;
 				create_recv_pending_htlc_info(decoded_hop, shared_secret, msg.payment_hash,
 					msg.amount_msat, msg.cltv_expiry, None, allow_underpay, msg.skimmed_fee_msat,
-					current_height)
+					msg.accountable.unwrap_or(false), current_height)
 			},
 			onion_utils::Hop::Forward { .. } | onion_utils::Hop::BlindedForward { .. } => {
 				create_fwd_pending_htlc_info(msg, decoded_hop, shared_secret, next_packet_pubkey_opt)
@@ -7375,6 +7378,7 @@ where
 								payment_hash,
 								outgoing_amt_msat,
 								outgoing_cltv_value,
+								incoming_accountable,
 								..
 							},
 					} = payment;
@@ -7473,6 +7477,7 @@ where
 								Some(phantom_shared_secret),
 								false,
 								None,
+								incoming_accountable,
 								current_height,
 							);
 							match create_res {
@@ -16248,6 +16253,7 @@ impl_writeable_tlv_based!(PendingHTLCInfo, {
 	(8, outgoing_cltv_value, required),
 	(9, incoming_amt_msat, option),
 	(10, skimmed_fee_msat, option),
+	(11, incoming_accountable, (default_value, false)),
 });
 
 impl Writeable for HTLCFailureMsg {
@@ -19837,7 +19843,7 @@ mod tests {
 		if let Err(crate::ln::channelmanager::InboundHTLCErr { reason, .. }) =
 			create_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
 				sender_intended_amt_msat - extra_fee_msat - 1, 42, None, true, Some(extra_fee_msat),
-				current_height)
+				false, current_height)
 		{
 			assert_eq!(reason, LocalHTLCFailureReason::FinalIncorrectHTLCAmount);
 		} else { panic!(); }
@@ -19860,7 +19866,7 @@ mod tests {
 		let current_height: u32 = node[0].node.best_block.read().unwrap().height;
 		assert!(create_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
 			sender_intended_amt_msat - extra_fee_msat, 42, None, true, Some(extra_fee_msat),
-			current_height).is_ok());
+			false, current_height).is_ok());
 	}
 
 	#[test]
@@ -19885,7 +19891,7 @@ mod tests {
 				custom_tlvs: Vec::new(),
 			},
 			shared_secret: SharedSecret::from_bytes([0; 32]),
-		}, [0; 32], PaymentHash([0; 32]), 100, TEST_FINAL_CLTV + 1, None, true, None, current_height);
+		}, [0; 32], PaymentHash([0; 32]), 100, TEST_FINAL_CLTV + 1, None, true, None, false, current_height);
 
 		// Should not return an error as this condition:
 		// https://github.com/lightning/bolts/blob/4dcc377209509b13cf89a4b91fde7d478f5b46d8/04-onion-routing.md?plain=1#L334

lightning/src/ln/onion_payment.rs

@@ -267,14 +267,15 @@ pub(super) fn create_fwd_pending_htlc_info(
 		outgoing_amt_msat: amt_to_forward,
 		outgoing_cltv_value,
 		skimmed_fee_msat: None,
+		incoming_accountable: msg.accountable.unwrap_or(false),
 	})
 }
 
 #[rustfmt::skip]
 pub(super) fn create_recv_pending_htlc_info(
 	hop_data: onion_utils::Hop, shared_secret: [u8; 32], payment_hash: PaymentHash,
 	amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
-	counterparty_skimmed_fee_msat: Option<u64>, current_height: u32
+	counterparty_skimmed_fee_msat: Option<u64>, incoming_accountable: bool, current_height: u32
 ) -> Result<PendingHTLCInfo, InboundHTLCErr> {
 	let (
 		payment_data, keysend_preimage, custom_tlvs, onion_amt_msat, onion_cltv_expiry,
@@ -456,6 +457,7 @@ pub(super) fn create_recv_pending_htlc_info(
 		outgoing_amt_msat: onion_amt_msat,
 		outgoing_cltv_value: onion_cltv_expiry,
 		skimmed_fee_msat: counterparty_skimmed_fee_msat,
+		incoming_accountable,
 	})
 }
 
@@ -520,7 +522,8 @@ where
 			let shared_secret = hop.shared_secret().secret_bytes();
 			create_recv_pending_htlc_info(
 				hop, shared_secret, msg.payment_hash, msg.amount_msat, msg.cltv_expiry,
-				None, allow_skimmed_fees, msg.skimmed_fee_msat, cur_height,
+				None, allow_skimmed_fees, msg.skimmed_fee_msat,
+				msg.accountable.unwrap_or(false), cur_height,
 			)?
 		}
 	})