Restrict ChannelInfo::as_directed_from visibility
[rust-lightning] / lightning / src / routing / router.rs
index 17253842e9214a871b177166557a9c06fd97698f..4c00dc5fcf9327126d0f9bd580823fd1447ea4f7 100644 (file)
@@ -238,8 +238,13 @@ pub struct PaymentParameters {
        /// A value of 0 will allow payments up to and including a channel's total announced usable
        /// capacity, a value of one will only use up to half its capacity, two 1/4, etc.
        ///
-       /// Default value: 1
+       /// Default value: 2
        pub max_channel_saturation_power_of_half: u8,
+
+       /// A list of SCIDs which this payment was previously attempted over and which caused the
+       /// payment to fail. Future attempts for the same payment shouldn't be relayed through any of
+       /// these SCIDs.
+       pub previously_failed_channels: Vec<u64>,
 }
 
 impl_writeable_tlv_based!(PaymentParameters, {
@@ -248,8 +253,9 @@ impl_writeable_tlv_based!(PaymentParameters, {
        (2, features, option),
        (3, max_path_count, (default_value, DEFAULT_MAX_PATH_COUNT)),
        (4, route_hints, vec_type),
-       (5, max_channel_saturation_power_of_half, (default_value, 1)),
+       (5, max_channel_saturation_power_of_half, (default_value, 2)),
        (6, expiry_time, option),
+       (7, previously_failed_channels, vec_type),
 });
 
 impl PaymentParameters {
@@ -262,7 +268,8 @@ impl PaymentParameters {
                        expiry_time: None,
                        max_total_cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA,
                        max_path_count: DEFAULT_MAX_PATH_COUNT,
-                       max_channel_saturation_power_of_half: 1,
+                       max_channel_saturation_power_of_half: 2,
+                       previously_failed_channels: Vec::new(),
                }
        }
 
@@ -747,7 +754,7 @@ where L::Target: Logger, GL::Target: Logger {
 pub(crate) fn get_route<L: Deref, S: Score>(
        our_node_pubkey: &PublicKey, payment_params: &PaymentParameters, network_graph: &ReadOnlyNetworkGraph,
        first_hops: Option<&[&ChannelDetails]>, final_value_msat: u64, final_cltv_expiry_delta: u32,
-       logger: L, scorer: &S, random_seed_bytes: &[u8; 32]
+       logger: L, scorer: &S, _random_seed_bytes: &[u8; 32]
 ) -> Result<Route, LightningError>
 where L::Target: Logger {
        let payee_node_id = NodeId::from_pubkey(&payment_params.payee_pubkey);
@@ -789,11 +796,11 @@ where L::Target: Logger {
        // 4. See if we managed to collect paths which aggregately are able to transfer target value
        //    (not recommended value).
        // 5. If yes, proceed. If not, fail routing.
-       // 6. Randomly combine paths into routes having enough to fulfill the payment. (TODO: knapsack)
-       // 7. Of all the found paths, select only those with the lowest total fee.
-       // 8. The last path in every selected route is likely to be more than we need.
-       //    Reduce its value-to-transfer and recompute fees.
-       // 9. Choose the best route by the lowest total fee.
+       // 6. Select the paths which have the lowest cost (fee plus scorer penalty) per amount
+       //    transferred up to the transfer target value.
+       // 7. Reduce the value of the last path until we are sending only the target value.
+       // 8. If our maximum channel saturation limit caused us to pick two identical paths, combine
+       //    them so that we're not sending two HTLCs along the same path.
 
        // As for the actual search algorithm,
        // we do a payee-to-payer pseudo-Dijkstra's sorting by each node's distance from the payee
@@ -1002,7 +1009,7 @@ where L::Target: Logger {
                                        let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat;
                                        // Do not consider candidate hops that would exceed the maximum path length.
                                        let path_length_to_node = $next_hops_path_length + 1;
-                                       let doesnt_exceed_max_path_length = path_length_to_node <= MAX_PATH_LENGTH_ESTIMATE;
+                                       let exceeds_max_path_length = path_length_to_node > MAX_PATH_LENGTH_ESTIMATE;
 
                                        // Do not consider candidates that exceed the maximum total cltv expiry limit.
                                        // In order to already account for some of the privacy enhancing random CLTV
@@ -1013,7 +1020,7 @@ where L::Target: Logger {
                                                .unwrap_or(payment_params.max_total_cltv_expiry_delta - final_cltv_expiry_delta);
                                        let hop_total_cltv_delta = ($next_hops_cltv_delta as u32)
                                                .saturating_add($candidate.cltv_expiry_delta());
-                                       let doesnt_exceed_cltv_delta_limit = hop_total_cltv_delta <= max_total_cltv_expiry_delta;
+                                       let exceeds_cltv_delta_limit = hop_total_cltv_delta > max_total_cltv_expiry_delta;
 
                                        let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution);
                                        // Includes paying fees for the use of the following channels.
@@ -1033,15 +1040,19 @@ where L::Target: Logger {
                                                 (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat &&
                                                  recommended_value_msat > $next_hops_path_htlc_minimum_msat));
 
+                                       let payment_failed_on_this_channel =
+                                               payment_params.previously_failed_channels.contains(&short_channel_id);
+
                                        // If HTLC minimum is larger than the amount we're going to transfer, we shouldn't
                                        // bother considering this channel. If retrying with recommended_value_msat may
                                        // allow us to hit the HTLC minimum limit, set htlc_minimum_limit so that we go
                                        // around again with a higher amount.
-                                       if contributes_sufficient_value && doesnt_exceed_max_path_length &&
-                                               doesnt_exceed_cltv_delta_limit && may_overpay_to_meet_path_minimum_msat {
+                                       if !contributes_sufficient_value || exceeds_max_path_length ||
+                                               exceeds_cltv_delta_limit || payment_failed_on_this_channel {
+                                               // Path isn't useful, ignore it and move on.
+                                       } else if may_overpay_to_meet_path_minimum_msat {
                                                hit_minimum_limit = true;
-                                       } else if contributes_sufficient_value && doesnt_exceed_max_path_length &&
-                                               doesnt_exceed_cltv_delta_limit && over_path_minimum_msat {
+                                       } else if over_path_minimum_msat {
                                                // Note that low contribution here (limited by available_liquidity_msat)
                                                // might violate htlc_minimum_msat on the hops which are next along the
                                                // payment path (upstream to the payee). To avoid that, we recompute
@@ -1465,7 +1476,7 @@ where L::Target: Logger {
                // Both these cases (and other cases except reaching recommended_value_msat) mean that
                // paths_collection will be stopped because found_new_path==false.
                // This is not necessarily a routing failure.
-               'path_construction: while let Some(RouteGraphNode { node_id, lowest_fee_to_node, total_cltv_delta, value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, path_length_to_node, .. }) = targets.pop() {
+               'path_construction: while let Some(RouteGraphNode { node_id, lowest_fee_to_node, total_cltv_delta, mut value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, path_length_to_node, .. }) = targets.pop() {
 
                        // Since we're going payee-to-payer, hitting our node as a target means we should stop
                        // traversing the graph and arrange the path out of what we found.
@@ -1531,7 +1542,9 @@ where L::Target: Logger {
                                // on some channels we already passed (assuming dest->source direction). Here, we
                                // recompute the fees again, so that if that's the case, we match the currently
                                // underpaid htlc_minimum_msat with fees.
-                               payment_path.update_value_and_recompute_fees(cmp::min(value_contribution_msat, final_value_msat));
+                               debug_assert_eq!(payment_path.get_value_msat(), value_contribution_msat);
+                               value_contribution_msat = cmp::min(value_contribution_msat, final_value_msat);
+                               payment_path.update_value_and_recompute_fees(value_contribution_msat);
 
                                // Since a path allows to transfer as much value as
                                // the smallest channel it has ("bottleneck"), we should recompute
@@ -1642,96 +1655,55 @@ where L::Target: Logger {
                return Err(LightningError{err: "Failed to find a sufficient route to the given destination".to_owned(), action: ErrorAction::IgnoreError});
        }
 
-       // Sort by total fees and take the best paths.
-       payment_paths.sort_unstable_by_key(|path| path.get_total_fee_paid_msat());
-       if payment_paths.len() > 50 {
-               payment_paths.truncate(50);
-       }
+       // Step (6).
+       let mut selected_route = payment_paths;
 
-       // Draw multiple sufficient routes by randomly combining the selected paths.
-       let mut drawn_routes = Vec::new();
-       let mut prng = ChaCha20::new(random_seed_bytes, &[0u8; 12]);
-       let mut random_index_bytes = [0u8; ::core::mem::size_of::<usize>()];
+       debug_assert_eq!(selected_route.iter().map(|p| p.get_value_msat()).sum::<u64>(), already_collected_value_msat);
+       let mut overpaid_value_msat = already_collected_value_msat - final_value_msat;
 
-       let num_permutations = payment_paths.len();
-       for _ in 0..num_permutations {
-               let mut cur_route = Vec::<PaymentPath>::new();
-               let mut aggregate_route_value_msat = 0;
+       // First, sort by the cost-per-value of the path, dropping the paths that cost the most for
+       // the value they contribute towards the payment amount.
+       // We sort in descending order as we will remove from the front in `retain`, next.
+       selected_route.sort_unstable_by(|a, b|
+               (((b.get_cost_msat() as u128) << 64) / (b.get_value_msat() as u128))
+                       .cmp(&(((a.get_cost_msat() as u128) << 64) / (a.get_value_msat() as u128)))
+       );
 
-               // Step (6).
-               // Do a Fisher-Yates shuffle to create a random permutation of the payment paths
-               for cur_index in (1..payment_paths.len()).rev() {
-                       prng.process_in_place(&mut random_index_bytes);
-                       let random_index = usize::from_be_bytes(random_index_bytes).wrapping_rem(cur_index+1);
-                       payment_paths.swap(cur_index, random_index);
+       // We should make sure that at least 1 path left.
+       let mut paths_left = selected_route.len();
+       selected_route.retain(|path| {
+               if paths_left == 1 {
+                       return true
+               }
+               let path_value_msat = path.get_value_msat();
+               if path_value_msat <= overpaid_value_msat {
+                       overpaid_value_msat -= path_value_msat;
+                       paths_left -= 1;
+                       return false;
                }
+               true
+       });
+       debug_assert!(selected_route.len() > 0);
 
+       if overpaid_value_msat != 0 {
                // Step (7).
-               for payment_path in &payment_paths {
-                       cur_route.push(payment_path.clone());
-                       aggregate_route_value_msat += payment_path.get_value_msat();
-                       if aggregate_route_value_msat > final_value_msat {
-                               // Last path likely overpaid. Substract it from the most expensive
-                               // (in terms of proportional fee) path in this route and recompute fees.
-                               // This might be not the most economically efficient way, but fewer paths
-                               // also makes routing more reliable.
-                               let mut overpaid_value_msat = aggregate_route_value_msat - final_value_msat;
-
-                               // First, we drop some expensive low-value paths entirely if possible, since fewer
-                               // paths is better: the payment is less likely to fail. In order to do so, we sort
-                               // by value and fall back to total fees paid, i.e., in case of equal values we
-                               // prefer lower cost paths.
-                               cur_route.sort_unstable_by(|a, b| {
-                                       a.get_value_msat().cmp(&b.get_value_msat())
-                                               // Reverse ordering for cost, so we drop higher-cost paths first
-                                               .then_with(|| b.get_cost_msat().cmp(&a.get_cost_msat()))
-                               });
-
-                               // We should make sure that at least 1 path left.
-                               let mut paths_left = cur_route.len();
-                               cur_route.retain(|path| {
-                                       if paths_left == 1 {
-                                               return true
-                                       }
-                                       let mut keep = true;
-                                       let path_value_msat = path.get_value_msat();
-                                       if path_value_msat <= overpaid_value_msat {
-                                               keep = false;
-                                               overpaid_value_msat -= path_value_msat;
-                                               paths_left -= 1;
-                                       }
-                                       keep
-                               });
-
-                               if overpaid_value_msat == 0 {
-                                       break;
-                               }
+               // Now, subtract the remaining overpaid value from the most-expensive path.
+               // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
+               // so that the sender pays less fees overall. And also htlc_minimum_msat.
+               selected_route.sort_unstable_by(|a, b| {
+                       let a_f = a.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>();
+                       let b_f = b.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>();
+                       a_f.cmp(&b_f).then_with(|| b.get_cost_msat().cmp(&a.get_cost_msat()))
+               });
+               let expensive_payment_path = selected_route.first_mut().unwrap();
 
-                               assert!(cur_route.len() > 0);
-
-                               // Step (8).
-                               // Now, subtract the overpaid value from the most-expensive path.
-                               // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
-                               // so that the sender pays less fees overall. And also htlc_minimum_msat.
-                               cur_route.sort_unstable_by_key(|path| { path.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>() });
-                               let expensive_payment_path = cur_route.first_mut().unwrap();
-
-                               // We already dropped all the small value paths above, meaning all the
-                               // remaining paths are larger than remaining overpaid_value_msat.
-                               // Thus, this can't be negative.
-                               let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat;
-                               expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat);
-                               break;
-                       }
-               }
-               drawn_routes.push(cur_route);
+               // We already dropped all the paths with value below `overpaid_value_msat` above, thus this
+               // can't go negative.
+               let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat;
+               expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat);
        }
 
-       // Step (9).
-       // Select the best route by lowest total cost.
-       drawn_routes.sort_unstable_by_key(|paths| paths.iter().map(|path| path.get_cost_msat()).sum::<u64>());
-       let selected_route = drawn_routes.first_mut().unwrap();
-
+       // Step (8).
        // Sort by the path itself and combine redundant paths.
        // Note that we sort by SCIDs alone as its simpler but when combining we have to ensure we
        // compare both SCIDs and NodeIds as individual nodes may use random aliases causing collisions
@@ -1960,7 +1932,7 @@ fn build_route_from_hops_internal<L: Deref>(
 
 #[cfg(test)]
 mod tests {
-       use routing::gossip::{NetworkGraph, P2PGossipSync, NodeId};
+       use routing::gossip::{NetworkGraph, P2PGossipSync, NodeId, EffectiveCapacity};
        use routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features,
                PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
                DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE};
@@ -1968,8 +1940,8 @@ mod tests {
        use chain::transaction::OutPoint;
        use chain::keysinterface::KeysInterface;
        use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
-       use ln::msgs::{ErrorAction, LightningError, OptionalField, UnsignedChannelAnnouncement, ChannelAnnouncement, RoutingMessageHandler,
-               NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate};
+       use ln::msgs::{ErrorAction, LightningError, UnsignedChannelAnnouncement, ChannelAnnouncement, RoutingMessageHandler,
+               NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate, MAX_VALUE_MSAT};
        use ln::channelmanager;
        use util::test_utils;
        use util::chacha20::ChaCha20;
@@ -1993,6 +1965,8 @@ mod tests {
        use prelude::*;
        use sync::{self, Arc};
 
+       use core::convert::TryInto;
+
        fn get_channel_details(short_channel_id: Option<u64>, node_id: PublicKey,
                        features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails {
                channelmanager::ChannelDetails {
@@ -2159,7 +2133,7 @@ mod tests {
                                flags: 0,
                                cltv_expiry_delta: 0,
                                htlc_minimum_msat: 0,
-                               htlc_maximum_msat: OptionalField::Absent,
+                               htlc_maximum_msat: MAX_VALUE_MSAT,
                                fee_base_msat: 0,
                                fee_proportional_millionths: 0,
                                excess_data: Vec::new()
@@ -2171,7 +2145,7 @@ mod tests {
                                flags: 1,
                                cltv_expiry_delta: 0,
                                htlc_minimum_msat: 0,
-                               htlc_maximum_msat: OptionalField::Absent,
+                               htlc_maximum_msat: MAX_VALUE_MSAT,
                                fee_base_msat: 0,
                                fee_proportional_millionths: 0,
                                excess_data: Vec::new()
@@ -2265,7 +2239,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2281,7 +2255,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (5 << 4) | 3,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: u32::max_value(),
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
@@ -2293,7 +2267,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2309,7 +2283,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (5 << 4) | 3,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: u32::max_value(),
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
@@ -2321,7 +2295,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2337,7 +2311,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (3 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2349,7 +2323,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (3 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 100,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2363,7 +2337,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (4 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 1000000,
                        excess_data: Vec::new()
@@ -2375,7 +2349,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (4 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2389,7 +2363,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (13 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 2000000,
                        excess_data: Vec::new()
@@ -2401,7 +2375,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (13 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2417,7 +2391,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (6 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2429,7 +2403,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (6 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new(),
@@ -2443,7 +2417,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (11 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2455,7 +2429,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (11 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2473,7 +2447,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (7 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 1000000,
                        excess_data: Vec::new()
@@ -2485,7 +2459,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (7 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2570,7 +2544,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2582,7 +2556,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2594,7 +2568,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2606,7 +2580,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2618,7 +2592,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2633,7 +2607,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 200_000_000,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2648,7 +2622,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(199_999_999),
+                       htlc_maximum_msat: 199_999_999,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2667,7 +2641,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2697,7 +2671,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 35_000,
-                       htlc_maximum_msat: OptionalField::Present(40_000),
+                       htlc_maximum_msat: 40_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2709,7 +2683,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 35_000,
-                       htlc_maximum_msat: OptionalField::Present(40_000),
+                       htlc_maximum_msat: 40_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2723,7 +2697,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2735,7 +2709,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2749,7 +2723,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2770,7 +2744,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 65_000,
-                       htlc_maximum_msat: OptionalField::Present(80_000),
+                       htlc_maximum_msat: 80_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2782,7 +2756,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2794,7 +2768,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 100_000,
                        excess_data: Vec::new()
@@ -2833,7 +2807,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -2845,7 +2819,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3251,7 +3225,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3263,7 +3237,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3323,7 +3297,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3335,7 +3309,7 @@ mod tests {
                        flags: 2, // to disable
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3668,7 +3642,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3680,7 +3654,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3695,7 +3669,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(1_000_000_000),
+                       htlc_maximum_msat: 1_000_000_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3710,7 +3684,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: 250_000_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3743,7 +3717,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(1_000_000_000),
+                       htlc_maximum_msat: 1_000_000_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3778,7 +3752,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(1_000_000_000),
+                       htlc_maximum_msat: 1_000_000_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3793,7 +3767,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(15_000),
+                       htlc_maximum_msat: 15_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3828,7 +3802,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3851,7 +3825,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (3 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: 15_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3863,7 +3837,7 @@ mod tests {
                        flags: 1,
                        cltv_expiry_delta: (3 << 4) | 2,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: 15_000,
                        fee_base_msat: 100,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3895,7 +3869,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(10_000),
+                       htlc_maximum_msat: 10_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3943,7 +3917,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3955,7 +3929,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3970,7 +3944,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3982,7 +3956,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -3995,7 +3969,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(50_000),
+                       htlc_maximum_msat: 50_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4007,7 +3981,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4064,7 +4038,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 1_000_000,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4076,7 +4050,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(50_000),
+                       htlc_maximum_msat: 50_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4121,7 +4095,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4133,7 +4107,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(50_000),
+                       htlc_maximum_msat: 50_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4148,7 +4122,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(60_000),
+                       htlc_maximum_msat: 60_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4160,7 +4134,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(60_000),
+                       htlc_maximum_msat: 60_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4175,7 +4149,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4187,7 +4161,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(180_000),
+                       htlc_maximum_msat: 180_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4278,7 +4252,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4290,7 +4264,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4304,7 +4278,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4316,7 +4290,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4331,7 +4305,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4347,7 +4321,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4359,7 +4333,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4372,7 +4346,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4384,7 +4358,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4446,7 +4420,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4458,7 +4432,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4472,7 +4446,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4484,7 +4458,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4499,7 +4473,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4515,7 +4489,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4527,7 +4501,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000),
+                       htlc_maximum_msat: 200_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4540,7 +4514,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 1_000,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4552,7 +4526,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4613,7 +4587,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4626,7 +4600,7 @@ mod tests {
                        flags: 2,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4640,7 +4614,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4652,7 +4626,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4666,7 +4640,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4689,7 +4663,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(250_000),
+                       htlc_maximum_msat: 250_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4701,7 +4675,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4714,7 +4688,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 150_000,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4726,7 +4700,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4783,7 +4757,7 @@ mod tests {
                                cltv_expiry_delta: 42,
                                htlc_minimum_msat: None,
                                htlc_maximum_msat: None,
-                       }])]);
+                       }])]).with_max_channel_saturation_power_of_half(0);
 
                // Keep only two paths from us to nodes[2], both with a 99sat HTLC maximum, with one with
                // no fee and one with a 1msat fee. Previously, trying to route 100 sats to nodes[2] here
@@ -4797,7 +4771,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (5 << 4) | 5,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(99_000),
+                       htlc_maximum_msat: 99_000,
                        fee_base_msat: u32::max_value(),
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
@@ -4809,7 +4783,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (5 << 4) | 3,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(99_000),
+                       htlc_maximum_msat: 99_000,
                        fee_base_msat: u32::max_value(),
                        fee_proportional_millionths: u32::max_value(),
                        excess_data: Vec::new()
@@ -4821,7 +4795,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (4 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 1,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4833,7 +4807,7 @@ mod tests {
                        flags: 0|2, // Channel disabled
                        cltv_expiry_delta: (13 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 2000000,
                        excess_data: Vec::new()
@@ -4886,7 +4860,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(100_000),
+                       htlc_maximum_msat: 100_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4898,7 +4872,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(50_000),
+                       htlc_maximum_msat: 50_000,
                        fee_base_msat: 100,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4912,7 +4886,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(60_000),
+                       htlc_maximum_msat: 60_000,
                        fee_base_msat: 100,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4924,7 +4898,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(60_000),
+                       htlc_maximum_msat: 60_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4938,7 +4912,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(20_000),
+                       htlc_maximum_msat: 20_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -4950,7 +4924,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(20_000),
+                       htlc_maximum_msat: 20_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5037,7 +5011,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (6 << 4) | 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5052,7 +5026,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (5 << 4) | 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 100,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5067,7 +5041,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (4 << 4) | 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5082,7 +5056,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (3 << 4) | 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5097,7 +5071,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (2 << 4) | 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5111,7 +5085,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (1 << 4) | 0,
                        htlc_minimum_msat: 100,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5169,7 +5143,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(85_000),
+                       htlc_maximum_msat: 85_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5182,7 +5156,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (4 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(270_000),
+                       htlc_maximum_msat: 270_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 1000000,
                        excess_data: Vec::new()
@@ -5234,7 +5208,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: 0,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(80_000),
+                       htlc_maximum_msat: 80_000,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5246,7 +5220,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (4 << 4) | 1,
                        htlc_minimum_msat: 90_000,
-                       htlc_maximum_msat: OptionalField::Absent,
+                       htlc_maximum_msat: MAX_VALUE_MSAT,
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5573,6 +5547,35 @@ mod tests {
                }
        }
 
+       #[test]
+       fn avoids_recently_failed_paths() {
+               // Ensure that the router always avoids all of the `previously_failed_channels` channels by
+               // randomly inserting channels into it until we can't find a route anymore.
+               let (secp_ctx, network, _, _, logger) = build_graph();
+               let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
+               let network_graph = network.read_only();
+
+               let scorer = test_utils::TestScorer::with_penalty(0);
+               let mut payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops(&nodes))
+                       .with_max_path_count(1);
+               let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
+               let random_seed_bytes = keys_manager.get_secure_random_bytes();
+
+               // We should be able to find a route initially, and then after we fail a few random
+               // channels eventually we won't be able to any longer.
+               assert!(get_route(&our_id, &payment_params, &network_graph, None, 100, 0, Arc::clone(&logger), &scorer, &random_seed_bytes).is_ok());
+               loop {
+                       if let Ok(route) = get_route(&our_id, &payment_params, &network_graph, None, 100, 0, Arc::clone(&logger), &scorer, &random_seed_bytes) {
+                               for chan in route.paths[0].iter() {
+                                       assert!(!payment_params.previously_failed_channels.contains(&chan.short_channel_id));
+                               }
+                               let victim = (u64::from_ne_bytes(random_seed_bytes[0..8].try_into().unwrap()) as usize)
+                                       % route.paths[0].len();
+                               payment_params.previously_failed_channels.push(route.paths[0][victim].short_channel_id);
+                       } else { break; }
+               }
+       }
+
        #[test]
        fn limits_path_length() {
                let (secp_ctx, network, _, _, logger) = build_line_graph();
@@ -5722,6 +5725,50 @@ mod tests {
                }
        }
 
+       #[test]
+       fn avoids_saturating_channels() {
+               let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph();
+               let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
+
+               let scorer = ProbabilisticScorer::new(Default::default(), &*network_graph, Arc::clone(&logger));
+
+               // Set the fee on channel 13 to 100% to match channel 4 giving us two equivalent paths (us
+               // -> node 7 -> node2 and us -> node 1 -> node 2) which we should balance over.
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
+                       chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+                       short_channel_id: 4,
+                       timestamp: 2,
+                       flags: 0,
+                       cltv_expiry_delta: (4 << 4) | 1,
+                       htlc_minimum_msat: 0,
+                       htlc_maximum_msat: 250_000_000,
+                       fee_base_msat: 0,
+                       fee_proportional_millionths: 0,
+                       excess_data: Vec::new()
+               });
+               update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
+                       chain_hash: genesis_block(Network::Testnet).header.block_hash(),
+                       short_channel_id: 13,
+                       timestamp: 2,
+                       flags: 0,
+                       cltv_expiry_delta: (13 << 4) | 1,
+                       htlc_minimum_msat: 0,
+                       htlc_maximum_msat: 250_000_000,
+                       fee_base_msat: 0,
+                       fee_proportional_millionths: 0,
+                       excess_data: Vec::new()
+               });
+
+               let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
+               let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
+               let random_seed_bytes = keys_manager.get_secure_random_bytes();
+               // 100,000 sats is less than the available liquidity on each channel, set above.
+               let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100_000_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+               assert_eq!(route.paths.len(), 2);
+               assert!((route.paths[0][1].short_channel_id == 4 && route.paths[1][1].short_channel_id == 13) ||
+                       (route.paths[1][1].short_channel_id == 4 && route.paths[0][1].short_channel_id == 13));
+       }
+
        #[cfg(not(feature = "no-std"))]
        pub(super) fn random_init_seed() -> u64 {
                // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
@@ -5808,7 +5855,7 @@ mod tests {
        }
 
        #[test]
-       fn avoids_banned_nodes() {
+       fn honors_manual_penalties() {
                let (secp_ctx, network_graph, _, _, logger) = build_line_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
 
@@ -5818,7 +5865,17 @@ mod tests {
                let scorer_params = ProbabilisticScoringParameters::default();
                let mut scorer = ProbabilisticScorer::new(scorer_params, Arc::clone(&network_graph), Arc::clone(&logger));
 
-               // First check we can get a route.
+               // First check set manual penalties are returned by the scorer.
+               let usage = ChannelUsage {
+                       amount_msat: 0,
+                       inflight_htlc_msat: 0,
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(1_000) },
+               };
+               scorer.set_manual_penalty(&NodeId::from_pubkey(&nodes[3]), 123);
+               scorer.set_manual_penalty(&NodeId::from_pubkey(&nodes[4]), 456);
+               assert_eq!(scorer.channel_penalty_msat(42, &NodeId::from_pubkey(&nodes[3]), &NodeId::from_pubkey(&nodes[4]), usage), 456);
+
+               // Then check we can get a normal route
                let payment_params = PaymentParameters::from_node_id(nodes[10]);
                let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100, 42, Arc::clone(&logger), &scorer, &random_seed_bytes);
                assert!(route.is_ok());