From: Gleb Naumenko Date: Mon, 10 Aug 2020 10:50:29 +0000 (+0300) Subject: Implement finding paths for MPP X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=d379f2f84c96d0ca0ccc79cf6d873f00753a5944;p=rust-lightning Implement finding paths for MPP --- diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs index 85dae7698..eef89d1b4 100644 --- a/lightning/src/ln/functional_tests.rs +++ b/lightning/src/ln/functional_tests.rs @@ -1960,7 +1960,8 @@ fn test_channel_reserve_holding_cell_htlcs() { // attempt to send amt_msat > their_max_htlc_value_in_flight_msat { - let (route, our_payment_hash, _) = get_route_and_payment_hash!(recv_value_0 + 1); + let (mut route, our_payment_hash, _) = get_route_and_payment_hash!(recv_value_0); + route.paths[0].last_mut().unwrap().fee_msat += 1; assert!(route.paths[0].iter().rev().skip(1).all(|h| h.fee_msat == feemsat)); unwrap_send_err!(nodes[0].node.send_payment(&route, our_payment_hash, &None), true, APIError::ChannelUnavailable { ref err }, assert!(regex::Regex::new(r"Cannot send value that would put us over the max HTLC value in flight our peer will accept \(\d+\)").unwrap().is_match(err))); @@ -6472,7 +6473,7 @@ fn test_update_add_htlc_bolt2_sender_cltv_expiry_too_high() { let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]); let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs); - let _chan = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 0, InitFeatures::known(), InitFeatures::known()); + let _chan = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1000000, 0, InitFeatures::known(), InitFeatures::known()); let logger = test_utils::TestLogger::new(); let (_, our_payment_hash) = get_payment_preimage_hash!(nodes[0]); @@ -6544,9 +6545,13 @@ fn test_update_add_htlc_bolt2_sender_exceed_max_htlc_value_in_flight() { send_payment(&nodes[0], &vec!(&nodes[1])[..], max_in_flight, max_in_flight); let (_, our_payment_hash) = get_payment_preimage_hash!(nodes[0]); - let net_graph_msg_handler = &nodes[0].net_graph_msg_handler; - let logger = test_utils::TestLogger::new(); - let route = get_route(&nodes[0].node.get_our_node_id(), &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[1].node.get_our_node_id(), None, &[], max_in_flight+1, TEST_FINAL_CLTV, &logger).unwrap(); + // Manually create a route over our max in flight (which our router normally automatically + // limits us to. + let route = Route { paths: vec![vec![RouteHop { + pubkey: nodes[1].node.get_our_node_id(), node_features: NodeFeatures::known(), channel_features: ChannelFeatures::known(), + short_channel_id: nodes[1].node.list_usable_channels()[0].short_channel_id.unwrap(), + fee_msat: max_in_flight + 1, cltv_expiry_delta: TEST_FINAL_CLTV + }]] }; unwrap_send_err!(nodes[0].node.send_payment(&route, our_payment_hash, &None), true, APIError::ChannelUnavailable { ref err }, assert!(regex::Regex::new(r"Cannot send value that would put us over the max HTLC value in flight our peer will accept \(\d+\)").unwrap().is_match(err))); diff --git a/lightning/src/routing/network_graph.rs b/lightning/src/routing/network_graph.rs index 8075462c9..6856bb16b 100644 --- a/lightning/src/routing/network_graph.rs +++ b/lightning/src/routing/network_graph.rs @@ -98,6 +98,13 @@ impl NetGraphMsgHandler where C::Target: chain::Access } } + /// Adds a provider used to check new announcements. Does not affect + /// existing announcements unless they are updated. + /// Add, update or remove the provider would replace the current one. + pub fn add_chain_access(&mut self, chain_access: Option) { + self.chain_access = chain_access; + } + /// Take a read lock on the network_graph and return it in the C-bindings /// newtype helper. This is likely only useful when called via the C /// bindings as you can call `self.network_graph.read().unwrap()` in Rust diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs index 0260aa1fd..ff5b307b1 100644 --- a/lightning/src/routing/router.rs +++ b/lightning/src/routing/router.rs @@ -22,7 +22,7 @@ use util::ser::{Writeable, Readable}; use util::logger::Logger; use std::cmp; -use std::collections::{HashMap,BinaryHeap}; +use std::collections::{HashMap, BinaryHeap}; use std::ops::Deref; /// A hop in a route @@ -38,7 +38,8 @@ pub struct RouteHop { /// The channel_announcement features of the channel that should be used from the previous hop /// to reach this node. pub channel_features: ChannelFeatures, - /// The fee taken on this hop. For the last hop, this should be the full value of the payment. + /// The fee taken on this hop (for paying for the use of the *next* channel in the path). + /// For the last hop, this should be the full value of the payment. pub fee_msat: u64, /// The CLTV delta added for this hop. For the last hop, this should be the full CLTV value /// expected at the destination, in excess of the current block height. @@ -134,6 +135,12 @@ struct RouteGraphNode { pubkey: PublicKey, lowest_fee_to_peer_through_node: u64, lowest_fee_to_node: u64, + // The maximum value a yet-to-be-constructed payment path might flow through this node. + // This value is upper-bounded by us by: + // - how much is needed for a path being constructed + // - how much value can channels following this node (up to the destination) can contribute, + // considering their capacity and fees + value_contribution_msat: u64 } impl cmp::Ord for RouteGraphNode { @@ -156,28 +163,138 @@ struct DummyDirectionalChannelInfo { fees: RoutingFees, } +/// It's useful to keep track of the hops associated with the fees required to use them, +/// so that we can choose cheaper paths (as per Dijkstra's algorithm). +/// Fee values should be updated only in the context of the whole path, see update_value_and_recompute_fees. +/// These fee values are useful to choose hops as we traverse the graph "payee-to-payer". +#[derive(Clone)] +struct PathBuildingHop { + /// Hop-specific details unrelated to the path during the routing phase, + /// but rather relevant to the LN graph. + route_hop: RouteHop, + /// Minimal fees required to route to the source node of the current hop via any of its inbound channels. + src_lowest_inbound_fees: RoutingFees, + /// Fees of the channel used in this hop. + channel_fees: RoutingFees, + /// All the fees paid *after* this channel on the way to the destination + next_hops_fee_msat: u64, + /// Fee paid for the use of the current channel (see channel_fees). + /// The value will be actually deducted from the counterparty balance on the previous link. + hop_use_fee_msat: u64, + /// Used to compare channels when choosing the for routing. + /// Includes paying for the use of a hop and the following hops, as well as + /// an estimated cost of reaching this hop. + /// Might get stale when fees are recomputed. Primarily for internal use. + total_fee_msat: u64, +} + +impl PathBuildingHop { + // What we are paying for the use of this channels and the following channels. + fn get_fee_paid_msat(&self) -> u64 { + if let Some(fee_paid_msat) = + self.next_hops_fee_msat.checked_add(self.hop_use_fee_msat) { + return fee_paid_msat; + } else { + return u64::max_value(); + } + } +} + +// Instantiated with a list of hops with correct data in them collected during path finding, +// an instance of this struct should be further modified only via given methods. +#[derive(Clone)] +struct PaymentPath { + hops: Vec, +} + +impl PaymentPath { + + // TODO: Add a value_msat field to PaymentPath and use it instead of this function. + fn get_value_msat(&self) -> u64 { + self.hops.last().unwrap().route_hop.fee_msat + } + + fn get_total_fee_paid_msat(&self) -> u64 { + if self.hops.len() < 1 { + return 0; + } + let mut result = 0; + // Can't use next_hops_fee_msat because it gets outdated. + for (i, hop) in self.hops.iter().enumerate() { + if i != self.hops.len() - 1 { + result += hop.route_hop.fee_msat; + } + } + return result; + } + + // If an amount transferred by the path is updated, the fees should be adjusted. + // Any other way to change fees may result in an inconsistency. + // The caller should make sure values don't fall below htlc_minimum_msat of the used channels. + fn update_value_and_recompute_fees(&mut self, value_msat: u64) { + let mut total_fee_paid_msat = 0 as u64; + for i in (1..self.hops.len()).rev() { + let cur_hop_amount_msat = total_fee_paid_msat + value_msat; + let mut cur_hop = self.hops.get_mut(i).unwrap(); + cur_hop.next_hops_fee_msat = total_fee_paid_msat; + if let Some(new_fee) = compute_fees(cur_hop_amount_msat, cur_hop.channel_fees) { + cur_hop.hop_use_fee_msat = new_fee; + total_fee_paid_msat += new_fee; + } else { + // It should not be possible because this function is called only to reduce the + // value. In that case, compute_fee was already called with the same fees for + // larger amount and there was no overflow. + unreachable!(); + } + } + + // Propagate updated fees for the use of the channels to one hop back, + // where they will be actually paid (fee_msat). + // For the last hop it will represent the value being transferred over this path. + for i in 0..self.hops.len() - 1 { + let next_hop_use_fee_msat = self.hops.get(i + 1).unwrap().hop_use_fee_msat; + self.hops.get_mut(i).unwrap().route_hop.fee_msat = next_hop_use_fee_msat; + } + self.hops.last_mut().unwrap().route_hop.fee_msat = value_msat; + self.hops.last_mut().unwrap().hop_use_fee_msat = 0; + } +} + +fn compute_fees(amount_msat: u64, channel_fees: RoutingFees) -> Option { + let proportional_fee_millions = + amount_msat.checked_mul(channel_fees.proportional_millionths as u64); + if let Some(new_fee) = proportional_fee_millions.and_then(|part| { + (channel_fees.base_msat as u64).checked_add(part / 1_000_000) }) { + + Some(new_fee) + } else { + // This function may be (indirectly) called without any verification, + // with channel_fees provided by a caller. We should handle it gracefully. + None + } +} -/// Gets a route from us to the given target node. +/// Gets a route from us (payer) to the given target node (payee). /// /// Extra routing hops between known nodes and the target will be used if they are included in /// last_hops. /// /// If some channels aren't announced, it may be useful to fill in a first_hops with the /// results from a local ChannelManager::list_usable_channels() call. If it is filled in, our -/// view of our local channels (from net_graph_msg_handler) will be ignored, and only those in first_hops -/// will be used. +/// view of our local channels (from net_graph_msg_handler) will be ignored, and only those +/// in first_hops will be used. /// /// Panics if first_hops contains channels without short_channel_ids /// (ChannelManager::list_usable_channels will never include such channels). /// /// The fees on channels from us to next-hops are ignored (as they are assumed to all be -/// equal), however the enabled/disabled bit on such channels as well as the htlc_minimum_msat -/// *is* checked as they may change based on the receiving node. -pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, target: &PublicKey, first_hops: Option<&[&ChannelDetails]>, +/// equal), however the enabled/disabled bit on such channels as well as the +/// htlc_minimum_msat/htlc_maximum_msat *are* checked as they may change based on the receiving node. +pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, payee: &PublicKey, first_hops: Option<&[&ChannelDetails]>, last_hops: &[&RouteHint], final_value_msat: u64, final_cltv: u32, logger: L) -> Result where L::Target: Logger { // TODO: Obviously *only* using total fee cost sucks. We should consider weighting by // uptime/success in using a node in the past. - if *target == *our_node_id { + if *payee == *our_node_id { return Err(LightningError{err: "Cannot generate a route to ourselves".to_owned(), action: ErrorAction::IgnoreError}); } @@ -185,7 +302,36 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ return Err(LightningError{err: "Cannot generate a route of more value than all existing satoshis".to_owned(), action: ErrorAction::IgnoreError}); } - // We do a dest-to-source Dijkstra's sorting by each node's distance from the destination + if final_value_msat == 0 { + return Err(LightningError{err: "Cannot send a payment of 0 msat".to_owned(), action: ErrorAction::IgnoreError}); + } + + for last_hop in last_hops { + if last_hop.src_node_id == *payee { + return Err(LightningError{err: "Last hop cannot have a payee as a source.".to_owned(), action: ErrorAction::IgnoreError}); + } + } + + // The general routing idea is the following: + // 1. Fill first/last hops communicated by the caller. + // 2. Attempt to construct a path from payer to payee for transferring + // any ~sufficient (described later) value. + // If succeed, remember which channels were used and how much liquidity they have available, + // so that future paths don't rely on the same liquidity. + // 3. Prooceed to the next step if: + // - we hit the recommended target value; + // - OR if we could not construct a new path. Any next attempt will fail too. + // Otherwise, repeat step 2. + // 4. See if we managed to collect paths which aggregately are able to transfer target value + // (not recommended value). If yes, proceed. If not, fail routing. + // 5. Randomly combine paths into routes having enough to fulfill the payment. (TODO: knapsack) + // 6. Of all the found paths, select only those with the lowest total fee. + // 7. The last path in every selected route is likely to be more than we need. + // Reduce its value-to-transfer and recompute fees. + // 8. Choose the best route by the lowest total fee. + + // As for the actual search algorithm, + // we do a payee-to-payer Dijkstra's sorting by each node's distance from the payee // plus the minimum per-HTLC fee to get from it to another node (aka "shitty A*"). // TODO: There are a few tweaks we could do, including possibly pre-calculating more stuff // to use as the A* heuristic beyond just the cost to get one node further than the current @@ -204,11 +350,23 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ let mut targets = BinaryHeap::new(); //TODO: Do we care about switching to eg Fibbonaci heap? let mut dist = HashMap::with_capacity(network.get_nodes().len()); + // When arranging a route, we select multiple paths so that we can make a multi-path payment. + // Don't stop searching for paths when we think they're + // sufficient to transfer a given value aggregately. + // Search for higher value, so that we collect many more paths, + // and then select the best combination among them. + const ROUTE_CAPACITY_PROVISION_FACTOR: u64 = 3; + let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64; + + // Step (1). + // Prepare the data we'll use for payee-to-payer search by + // inserting first hops suggested by the caller as targets. + // Our search will then attempt to reach them while traversing from the payee node. let mut first_hop_targets = HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 }); if let Some(hops) = first_hops { for chan in hops { let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones"); - if chan.remote_network_id == *target { + if chan.remote_network_id == *payee { return Ok(Route { paths: vec![vec![RouteHop { pubkey: chan.remote_network_id, @@ -219,6 +377,8 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ cltv_expiry_delta: final_cltv, }]], }); + } else if chan.remote_network_id == *our_node_id { + return Err(LightningError{err: "First hop cannot have our_node_id as a destination.".to_owned(), action: ErrorAction::IgnoreError}); } first_hop_targets.insert(chan.remote_network_id, (short_channel_id, chan.counterparty_features.clone())); } @@ -227,89 +387,209 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ } } + // We don't want multiple paths (as per MPP) share liquidity of the same channels. + // This map allows paths to be aware of the channel use by other paths in the same call. + // This would help to make a better path finding decisions and not "overbook" channels. + // It is unaware of the directions. + // TODO: we could let a caller specify this. Definitely useful when considering our own channels. + let mut bookkeeped_channels_liquidity_available_msat = HashMap::new(); + + // Keeping track of how much value we already collected across other paths. Helps to decide: + // - how much a new path should be transferring (upper bound); + // - whether a channel should be disregarded because + // it's available liquidity is too small comparing to how much more we need to collect; + // - when we want to stop looking for new paths. + let mut already_collected_value_msat = 0; + macro_rules! add_entry { // Adds entry which goes from $src_node_id to $dest_node_id // over the channel with id $chan_id with fees described in // $directional_info. - ( $chan_id: expr, $src_node_id: expr, $dest_node_id: expr, $directional_info: expr, $capacity_sats: expr, $chan_features: expr, $starting_fee_msat: expr ) => { - //TODO: Explore simply adding fee to hit htlc_minimum_msat - if $starting_fee_msat as u64 + final_value_msat >= $directional_info.htlc_minimum_msat { - let proportional_fee_millions = ($starting_fee_msat + final_value_msat).checked_mul($directional_info.fees.proportional_millionths as u64); - if let Some(new_fee) = proportional_fee_millions.and_then(|part| { - ($directional_info.fees.base_msat as u64).checked_add(part / 1000000) }) - { - let mut total_fee = $starting_fee_msat as u64; - - let mut available_msat = $capacity_sats; + // $next_hops_fee_msat represents the fees paid for using all the channel *after* this one, + // since that value has to be transferred over this channel. + ( $chan_id: expr, $src_node_id: expr, $dest_node_id: expr, $directional_info: expr, $capacity_sats: expr, $chan_features: expr, $next_hops_fee_msat: expr, + $next_hops_value_contribution: expr ) => { + // Channels to self should not be used. This is more of belt-and-suspenders, because in + // practice these cases should be caught earlier: + // - for regular channels at channel announcement (TODO) + // - for first and last hops early in get_route + if $src_node_id != $dest_node_id.clone() { + let available_liquidity_msat = bookkeeped_channels_liquidity_available_msat.entry($chan_id.clone()).or_insert_with(|| { + let mut initial_liquidity_available_msat = None; + if let Some(capacity_sats) = $capacity_sats { + initial_liquidity_available_msat = Some(capacity_sats * 1000); + } + if let Some(htlc_maximum_msat) = $directional_info.htlc_maximum_msat { - if let Some(capacity_sats) = $capacity_sats { - available_msat = Some(cmp::min(capacity_sats * 1000, htlc_maximum_msat)); + if let Some(available_msat) = initial_liquidity_available_msat { + initial_liquidity_available_msat = Some(cmp::min(available_msat, htlc_maximum_msat)); } else { - available_msat = Some(htlc_maximum_msat); + initial_liquidity_available_msat = Some(htlc_maximum_msat); } } - let hm_entry = dist.entry(&$src_node_id); - let old_entry = hm_entry.or_insert_with(|| { - let mut fee_base_msat = u32::max_value(); - let mut fee_proportional_millionths = u32::max_value(); - if let Some(fees) = network.get_nodes().get(&$src_node_id).and_then(|node| node.lowest_inbound_channel_fees) { - fee_base_msat = fees.base_msat; - fee_proportional_millionths = fees.proportional_millionths; + match initial_liquidity_available_msat { + Some(available_msat) => available_msat, + // We assume channels with unknown balance have + // a capacity of 0.0025 BTC (or 250_000 sats). + None => 250_000 * 1000 + } + }); + + // It is tricky to substract $next_hops_fee_msat from available liquidity here. + // It may be misleading because we might later choose to reduce the value transferred + // over these channels, and the channel which was insufficient might become sufficient. + // Worst case: we drop a good channel here because it can't cover the high following + // fees caused by one expensive channel, but then this channel could have been used + // if the amount being transferred over this path is lower. + // We do this for now, but this is a subject for removal. + if let Some(available_value_contribution_msat) = available_liquidity_msat.checked_sub($next_hops_fee_msat) { + + // Routing Fragmentation Mitigation heuristic: + // + // Routing fragmentation across many payment paths increases the overall routing + // fees as you have irreducible routing fees per-link used (`fee_base_msat`). + // Taking too many smaller paths also increases the chance of payment failure. + // Thus to avoid this effect, we require from our collected links to provide + // at least a minimal contribution to the recommended value yet-to-be-fulfilled. + // + // This requirement is currently 5% of the remaining-to-be-collected value. + // This means as we successfully advance in our collection, + // the absolute liquidity contribution is lowered, + // thus increasing the number of potential channels to be selected. + + // Derive the minimal liquidity contribution with a ratio of 20 (5%, rounded up). + let minimal_value_contribution_msat: u64 = (recommended_value_msat - already_collected_value_msat + 19) / 20; + // Verify the liquidity offered by this channel complies to the minimal contribution. + let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat; + + let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution); + // Includes paying fees for the use of the following channels. + let amount_to_transfer_over_msat: u64 = match value_contribution_msat.checked_add($next_hops_fee_msat) { + Some(result) => result, + // Can't overflow due to how the values were computed right above. + None => unreachable!(), + }; + + // If HTLC minimum is larger than the whole value we're going to transfer, we shouldn't bother + // even considering this channel, because it won't be useful. + // TODO: Explore simply adding fee to hit htlc_minimum_msat + // This is separate from checking amount_to_transfer_over_msat, which also should be + // lower-bounded by htlc_minimum_msat. Since we're choosing it as maximum possible, + // this channel should just be skipped if it's not sufficient. + // amount_to_transfer_over_msat can be both larger and smaller than final_value_msat, + // so this can't be derived. + let final_value_satisfies_htlc_minimum_msat = final_value_msat >= $directional_info.htlc_minimum_msat; + if final_value_satisfies_htlc_minimum_msat && + contributes_sufficient_value && amount_to_transfer_over_msat >= $directional_info.htlc_minimum_msat { + let hm_entry = dist.entry(&$src_node_id); + let old_entry = hm_entry.or_insert_with(|| { + // If there was previously no known way to access + // the source node (recall it goes payee-to-payer) of $chan_id, first add + // a semi-dummy record just to compute the fees to reach the source node. + // This will affect our decision on selecting $chan_id + // as a way to reach the $dest_node_id. + let mut fee_base_msat = u32::max_value(); + let mut fee_proportional_millionths = u32::max_value(); + if let Some(Some(fees)) = network.get_nodes().get(&$src_node_id).map(|node| node.lowest_inbound_channel_fees) { + fee_base_msat = fees.base_msat; + fee_proportional_millionths = fees.proportional_millionths; + } + PathBuildingHop { + route_hop: RouteHop { + pubkey: $dest_node_id.clone(), + node_features: NodeFeatures::empty(), + short_channel_id: 0, + channel_features: $chan_features.clone(), + fee_msat: 0, + cltv_expiry_delta: 0, + }, + src_lowest_inbound_fees: RoutingFees { + base_msat: fee_base_msat, + proportional_millionths: fee_proportional_millionths, + }, + channel_fees: $directional_info.fees, + next_hops_fee_msat: u64::max_value(), + hop_use_fee_msat: u64::max_value(), + total_fee_msat: u64::max_value(), + } + }); + + let mut hop_use_fee_msat = 0; + let mut total_fee_msat = $next_hops_fee_msat; + + // Ignore hop_use_fee_msat for channel-from-us as we assume all channels-from-us + // will have the same effective-fee + if $src_node_id != *our_node_id { + match compute_fees(amount_to_transfer_over_msat, $directional_info.fees) { + // max_value means we'll always fail + // the old_entry.total_fee_msat > total_fee_msat check + None => total_fee_msat = u64::max_value(), + Some(fee_msat) => { + hop_use_fee_msat = fee_msat; + total_fee_msat += hop_use_fee_msat; + if let Some(prev_hop_fee_msat) = compute_fees(total_fee_msat + amount_to_transfer_over_msat, + old_entry.src_lowest_inbound_fees) { + if let Some(incremented_total_fee_msat) = total_fee_msat.checked_add(prev_hop_fee_msat) { + total_fee_msat = incremented_total_fee_msat; + } + else { + // max_value means we'll always fail + // the old_entry.total_fee_msat > total_fee_msat check + total_fee_msat = u64::max_value(); + } + } else { + // max_value means we'll always fail + // the old_entry.total_fee_msat > total_fee_msat check + total_fee_msat = u64::max_value(); + } + } + } } - (u64::max_value(), - fee_base_msat, - fee_proportional_millionths, - RouteHop { + + let new_graph_node = RouteGraphNode { + pubkey: $src_node_id, + lowest_fee_to_peer_through_node: total_fee_msat, + lowest_fee_to_node: $next_hops_fee_msat as u64 + hop_use_fee_msat, + value_contribution_msat: value_contribution_msat, + }; + + // Update the way of reaching $src_node_id with the given $chan_id (from $dest_node_id), + // if this way is cheaper than the already known + // (considering the cost to "reach" this channel from the route destination, + // the cost of using this channel, + // and the cost of routing to the source node of this channel). + if old_entry.total_fee_msat > total_fee_msat { + targets.push(new_graph_node); + old_entry.next_hops_fee_msat = $next_hops_fee_msat; + old_entry.hop_use_fee_msat = hop_use_fee_msat; + old_entry.total_fee_msat = total_fee_msat; + old_entry.route_hop = RouteHop { pubkey: $dest_node_id.clone(), node_features: NodeFeatures::empty(), - short_channel_id: 0, + short_channel_id: $chan_id.clone(), channel_features: $chan_features.clone(), - fee_msat: 0, - cltv_expiry_delta: 0, - }, - None, - ) - }); - if $src_node_id != *our_node_id { - // Ignore new_fee for channel-from-us as we assume all channels-from-us - // will have the same effective-fee - total_fee += new_fee; - if let Some(fee_inc) = final_value_msat.checked_add(total_fee).and_then(|inc| { (old_entry.2 as u64).checked_mul(inc) }) { - total_fee += fee_inc / 1000000 + (old_entry.1 as u64); - } else { - // max_value means we'll always fail the old_entry.0 > total_fee check - total_fee = u64::max_value(); + fee_msat: 0, // This value will be later filled with hop_use_fee_msat of the following channel + cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32, + }; + old_entry.channel_fees = $directional_info.fees; } } - let new_graph_node = RouteGraphNode { - pubkey: $src_node_id, - lowest_fee_to_peer_through_node: total_fee, - lowest_fee_to_node: $starting_fee_msat as u64 + new_fee, - }; - if old_entry.0 > total_fee { - targets.push(new_graph_node); - old_entry.0 = total_fee; - old_entry.3 = RouteHop { - pubkey: $dest_node_id.clone(), - node_features: NodeFeatures::empty(), - short_channel_id: $chan_id.clone(), - channel_features: $chan_features.clone(), - fee_msat: new_fee, // This field is ignored on the last-hop anyway - cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32, - }; - old_entry.4 = available_msat; - } } } }; } + // Find ways (channels with destination) to reach a given node and store them + // in the corresponding data structures (routing graph etc). + // $fee_to_target_msat represents how much it costs to reach to this node from the payee, + // meaning how much will be paid in fees after this node (to the best of our knowledge). + // This data can later be helpful to optimize routing (pay lower fees). macro_rules! add_entries_to_cheapest_to_target_node { - ( $node: expr, $node_id: expr, $fee_to_target_msat: expr ) => { + ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr ) => { if first_hops.is_some() { if let Some(&(ref first_hop, ref features)) = first_hop_targets.get(&$node_id) { - add_entry!(first_hop, *our_node_id, $node_id, dummy_directional_info, None::, features.to_context(), $fee_to_target_msat); + add_entry!(first_hop, *our_node_id, $node_id, dummy_directional_info, None::, features.to_context(), $fee_to_target_msat, $next_hops_value_contribution); } } @@ -329,7 +609,7 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ if first_hops.is_none() || chan.node_two != *our_node_id { if let Some(two_to_one) = chan.two_to_one.as_ref() { if two_to_one.enabled { - add_entry!(chan_id, chan.node_two, chan.node_one, two_to_one, chan.capacity_sats, chan.features, $fee_to_target_msat); + add_entry!(chan_id, chan.node_two, chan.node_one, two_to_one, chan.capacity_sats, chan.features, $fee_to_target_msat, $next_hops_value_contribution); } } } @@ -337,7 +617,7 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ if first_hops.is_none() || chan.node_one != *our_node_id { if let Some(one_to_two) = chan.one_to_two.as_ref() { if one_to_two.enabled { - add_entry!(chan_id, chan.node_one, chan.node_two, one_to_two, chan.capacity_sats, chan.features, $fee_to_target_msat); + add_entry!(chan_id, chan.node_one, chan.node_two, one_to_two, chan.capacity_sats, chan.features, $fee_to_target_msat, $next_hops_value_contribution); } } @@ -349,94 +629,282 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ }; } - match network.get_nodes().get(target) { - None => {}, - Some(node) => { - add_entries_to_cheapest_to_target_node!(node, target, 0); - }, - } + let mut payment_paths = Vec::::new(); + + // TODO: diversify by nodes (so that all paths aren't doomed if one node is offline). + 'paths_collection: loop { + // For every new path, start from scratch, except + // bookkeeped_channels_liquidity_available_msat, which will improve + // the further iterations of path finding. Also don't erase first_hop_targets. + targets.clear(); + dist.clear(); + + // Add the payee as a target, so that the payee-to-payer + // search algorithm knows what to start with. + match network.get_nodes().get(payee) { + // The payee is not in our network graph, so nothing to add here. + // There is still a chance of reaching them via last_hops though, + // so don't yet fail the payment here. + // If not, targets.pop() will not even let us enter the loop in step 2. + None => {}, + Some(node) => { + add_entries_to_cheapest_to_target_node!(node, payee, 0, recommended_value_msat); + }, + } - for hop in last_hops.iter() { - let have_hop_src_in_graph = - if let Some(&(ref first_hop, ref features)) = first_hop_targets.get(&hop.src_node_id) { - // If this hop connects to a node with which we have a direct channel, ignore the - // network graph and add both the hop and our direct channel to the candidate set: - // - // Currently there are no channel-context features defined, so we are a - // bit lazy here. In the future, we should pull them out via our - // ChannelManager, but there's no reason to waste the space until we - // need them. - add_entry!(first_hop, *our_node_id , hop.src_node_id, dummy_directional_info, None::, features.to_context(), 0); - true - } else { - // In any other case, only add the hop if the source is in the regular network - // graph: - network.get_nodes().get(&hop.src_node_id).is_some() - }; - if have_hop_src_in_graph { - // BOLT 11 doesn't allow inclusion of features for the last hop hints, which - // really sucks, cause we're gonna need that eventually. - let last_hop_htlc_minimum_msat: u64 = match hop.htlc_minimum_msat { - Some(htlc_minimum_msat) => htlc_minimum_msat, - None => 0 - }; - let directional_info = DummyDirectionalChannelInfo { - cltv_expiry_delta: hop.cltv_expiry_delta as u32, - htlc_minimum_msat: last_hop_htlc_minimum_msat, - htlc_maximum_msat: hop.htlc_maximum_msat, - fees: hop.fees, - }; - add_entry!(hop.short_channel_id, hop.src_node_id, target, directional_info, None::, ChannelFeatures::empty(), 0); + // Step (1). + // If a caller provided us with last hops, add them to routing targets. Since this happens + // earlier than general path finding, they will be somewhat prioritized, although currently + // it matters only if the fees are exactly the same. + for hop in last_hops.iter() { + let have_hop_src_in_graph = + if let Some(&(ref first_hop, ref features)) = first_hop_targets.get(&hop.src_node_id) { + // If this hop connects to a node with which we have a direct channel, ignore + // the network graph and add both the hop and our direct channel to + // the candidate set. + // + // Currently there are no channel-context features defined, so we are a + // bit lazy here. In the future, we should pull them out via our + // ChannelManager, but there's no reason to waste the space until we + // need them. + add_entry!(first_hop, *our_node_id , hop.src_node_id, dummy_directional_info, None::, features.to_context(), 0, recommended_value_msat); + true + } else { + // In any other case, only add the hop if the source is in the regular network + // graph: + network.get_nodes().get(&hop.src_node_id).is_some() + }; + if have_hop_src_in_graph { + // BOLT 11 doesn't allow inclusion of features for the last hop hints, which + // really sucks, cause we're gonna need that eventually. + let last_hop_htlc_minimum_msat: u64 = match hop.htlc_minimum_msat { + Some(htlc_minimum_msat) => htlc_minimum_msat, + None => 0 + }; + let directional_info = DummyDirectionalChannelInfo { + cltv_expiry_delta: hop.cltv_expiry_delta as u32, + htlc_minimum_msat: last_hop_htlc_minimum_msat, + htlc_maximum_msat: hop.htlc_maximum_msat, + fees: hop.fees, + }; + add_entry!(hop.short_channel_id, hop.src_node_id, payee, directional_info, None::, ChannelFeatures::empty(), 0, recommended_value_msat); + } } - } - while let Some(RouteGraphNode { pubkey, lowest_fee_to_node, .. }) = targets.pop() { - if pubkey == *our_node_id { - let mut res = vec!(dist.remove(&our_node_id).unwrap().3); - loop { - if let Some(&(_, ref features)) = first_hop_targets.get(&res.last().unwrap().pubkey) { - res.last_mut().unwrap().node_features = features.to_context(); - } else if let Some(node) = network.get_nodes().get(&res.last().unwrap().pubkey) { - if let Some(node_info) = node.announcement_info.as_ref() { - res.last_mut().unwrap().node_features = node_info.features.clone(); + // At this point, targets are filled with the data from first and + // last hops communicated by the caller, and the payment receiver. + let mut found_new_path = false; + + // Step (2). + // If this loop terminates due the exhaustion of targets, two situations are possible: + // - not enough outgoing liquidity: + // 0 < already_collected_value_msat < final_value_msat + // - enough outgoing liquidity: + // final_value_msat <= already_collected_value_msat < recommended_value_msat + // 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 { pubkey, lowest_fee_to_node, value_contribution_msat, .. }) = 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. + if pubkey == *our_node_id { + let mut new_entry = dist.remove(&our_node_id).unwrap(); + let mut ordered_hops = vec!(new_entry.clone()); + + 'path_walk: loop { + if let Some(&(_, ref features)) = first_hop_targets.get(&ordered_hops.last().unwrap().route_hop.pubkey) { + ordered_hops.last_mut().unwrap().route_hop.node_features = features.to_context(); + } else if let Some(node) = network.get_nodes().get(&ordered_hops.last().unwrap().route_hop.pubkey) { + if let Some(node_info) = node.announcement_info.as_ref() { + ordered_hops.last_mut().unwrap().route_hop.node_features = node_info.features.clone(); + } else { + ordered_hops.last_mut().unwrap().route_hop.node_features = NodeFeatures::empty(); + } } else { - res.last_mut().unwrap().node_features = NodeFeatures::empty(); + // We should be able to fill in features for everything except the last + // hop, if the last hop was provided via a BOLT 11 invoice (though we + // should be able to extend it further as BOLT 11 does have feature + // flags for the last hop node itself). + assert!(ordered_hops.last().unwrap().route_hop.pubkey == *payee); } - } else { - // We should be able to fill in features for everything except the last - // hop, if the last hop was provided via a BOLT 11 invoice (though we - // should be able to extend it further as BOLT 11 does have feature - // flags for the last hop node itself). - assert!(res.last().unwrap().pubkey == *target); + + // Means we succesfully traversed from the payer to the payee, now + // save this path for the payment route. Also, update the liquidity + // remaining on the used hops, so that we take them into account + // while looking for more paths. + if ordered_hops.last().unwrap().route_hop.pubkey == *payee { + break 'path_walk; + } + + new_entry = match dist.remove(&ordered_hops.last().unwrap().route_hop.pubkey) { + Some(payment_hop) => payment_hop, + None => { + // If we can't reach a given node, something went wrong + // during path traverse. + // Stop looking for more paths here because next iterations + // will face the exact same issue. + break 'paths_collection; + } + }; + // We "propagate" the fees one hop backward (topologically) here, + // so that fees paid for a HTLC forwarding on the current channel are + // associated with the previous channel (where they will be subtracted). + ordered_hops.last_mut().unwrap().route_hop.fee_msat = new_entry.hop_use_fee_msat; + ordered_hops.last_mut().unwrap().route_hop.cltv_expiry_delta = new_entry.route_hop.cltv_expiry_delta; + ordered_hops.push(new_entry.clone()); } - if res.last().unwrap().pubkey == *target { - break; + ordered_hops.last_mut().unwrap().route_hop.fee_msat = value_contribution_msat; + ordered_hops.last_mut().unwrap().hop_use_fee_msat = 0; + ordered_hops.last_mut().unwrap().route_hop.cltv_expiry_delta = final_cltv; + + let payment_path = PaymentPath {hops: ordered_hops}; + // Since a path allows to transfer as much value as + // the smallest channel it has ("bottleneck"), we should recompute + // the fees so sender HTLC don't overpay fees when traversing + // larger channels than the bottleneck. This may happen because + // when we were selecting those channels we were not aware how much value + // this path will transfer, and the relative fee for them + // might have been computed considering a larger value. + // Remember that we used these channels so that we don't rely + // on the same liquidity in future paths. + for (i, payment_hop) in payment_path.hops.iter().enumerate() { + let channel_liquidity_available_msat = bookkeeped_channels_liquidity_available_msat.get_mut(&payment_hop.route_hop.short_channel_id).unwrap(); + let mut spent_on_hop_msat = value_contribution_msat; + let hop_and_after_fee = payment_hop.get_fee_paid_msat(); + if i == payment_path.hops.len() - 1 { + // For the last hop the fee should always be 0. + assert_eq!(hop_and_after_fee, 0); + } + spent_on_hop_msat += hop_and_after_fee; + if *channel_liquidity_available_msat < spent_on_hop_msat { + // This should not happen because we do recompute fees right before, + // trying to avoid cases when a hop is not usable due to the fee situation. + break 'path_construction; + } + *channel_liquidity_available_msat -= spent_on_hop_msat; } + // Track the total amount all our collected paths allow to send so that we: + // - know when to stop looking for more paths + // - know which of the hops are useless considering how much more sats we need + // (contributes_sufficient_value) + already_collected_value_msat += value_contribution_msat; + + payment_paths.push(payment_path); + found_new_path = true; + break 'path_construction; + } - let new_entry = match dist.remove(&res.last().unwrap().pubkey) { - Some(hop) => hop.3, - None => return Err(LightningError{err: "Failed to find a non-fee-overflowing path to the given destination".to_owned(), action: ErrorAction::IgnoreError}), - }; - res.last_mut().unwrap().fee_msat = new_entry.fee_msat; - res.last_mut().unwrap().cltv_expiry_delta = new_entry.cltv_expiry_delta; - res.push(new_entry); + // Otherwise, since the current target node is not us, + // keep "unrolling" the payment graph from payee to payer by + // finding a way to reach the current target from the payer side. + match network.get_nodes().get(&pubkey) { + None => {}, + Some(node) => { + add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node, value_contribution_msat); + }, } - res.last_mut().unwrap().fee_msat = final_value_msat; - res.last_mut().unwrap().cltv_expiry_delta = final_cltv; - let route = Route { paths: vec![res] }; - log_trace!(logger, "Got route: {}", log_route!(route)); - return Ok(route); } - match network.get_nodes().get(&pubkey) { - None => {}, - Some(node) => { - add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node); - }, + // Step (3). + // Stop either when recommended value is reached, + // or if during last iteration no new path was found. + // In the latter case, making another path finding attempt could not help, + // because we deterministically terminate the search due to low liquidity. + if already_collected_value_msat >= recommended_value_msat || !found_new_path { + break 'paths_collection; + } + } + + // Step (4). + if payment_paths.len() == 0 { + return Err(LightningError{err: "Failed to find a path to the given destination".to_owned(), action: ErrorAction::IgnoreError}); + } + + if already_collected_value_msat < final_value_msat { + 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_by_key(|path| path.get_total_fee_paid_msat()); + if payment_paths.len() > 50 { + payment_paths.truncate(50); + } + + // Draw multiple sufficient routes by randomly combining the selected paths. + let mut drawn_routes = Vec::new(); + for i in 0..payment_paths.len() { + let mut cur_route = Vec::::new(); + let mut aggregate_route_value_msat = 0; + + // Step (5). + // TODO: real random shuffle + // Currently just starts with i_th and goes up to i-1_th in a looped way. + let cur_payment_paths = [&payment_paths[i..], &payment_paths[..i]].concat(); + + // Step (6). + for payment_path in cur_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, drop some expensive low-value paths entirely if possible. + // Sort by value so that we drop many really-low values first, since + // fewer paths is better: the payment is less likely to fail. + // TODO: this could also be optimized by also sorting by feerate_per_sat_routed, + // so that the sender pays less fees overall. + cur_route.sort_by_key(|path| path.get_value_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; + } + + assert!(cur_route.len() > 0); + + // Step (7). + // Now, substract the overpaid value from the most-expensive path. + cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.channel_fees.proportional_millionths as u64).sum::() }); + let expensive_payment_path = cur_route.last_mut().unwrap(); + let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat; + // TODO: make sure expensive_path_new_value_msat doesn't cause to fall behind htlc_minimum_msat. + expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat); + break; + } } + drawn_routes.push(cur_route); + } + + // Step (8). + // Select the best route by lowest total fee. + drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::()); + let mut selected_paths = Vec::>::new(); + for payment_path in drawn_routes.first().unwrap() { + selected_paths.push(payment_path.hops.iter().map(|payment_hop| payment_hop.route_hop.clone()).collect()); } - Err(LightningError{err: "Failed to find a path to the given destination".to_owned(), action: ErrorAction::IgnoreError}) + let route = Route { paths: selected_paths }; + log_trace!(logger, "Got route: {}", log_route!(route)); + return Ok(route); } #[cfg(test)] @@ -454,6 +922,9 @@ mod tests { use bitcoin::hashes::Hash; use bitcoin::network::constants::Network; use bitcoin::blockdata::constants::genesis_block; + use bitcoin::blockdata::script::Builder; + use bitcoin::blockdata::opcodes; + use bitcoin::blockdata::transaction::TxOut; use hex; @@ -502,12 +973,10 @@ mod tests { match net_graph_msg_handler.handle_channel_update(&valid_channel_update) { Ok(res) => assert!(res), - // Err(_) => panic!() - Err(e) => println!("{:?}", e.err) + Err(_) => panic!() }; } - fn add_or_update_node(net_graph_msg_handler: &NetGraphMsgHandler, Arc>, secp_ctx: &Secp256k1, node_privkey: &SecretKey, features: NodeFeatures, timestamp: u32) { let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey); @@ -561,9 +1030,10 @@ mod tests { } } - fn build_graph() -> (Secp256k1, NetGraphMsgHandler, std::sync::Arc>, std::sync::Arc) { + fn build_graph() -> (Secp256k1, NetGraphMsgHandler, std::sync::Arc>, std::sync::Arc, std::sync::Arc) { let secp_ctx = Secp256k1::new(); let logger = Arc::new(test_utils::TestLogger::new()); + let chain_monitor = Arc::new(test_utils::TestChainSource::new(Network::Testnet)); let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), None, Arc::clone(&logger)); // Build network from our_id to node7: // @@ -860,15 +1330,20 @@ mod tests { add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[5], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0); - (secp_ctx, net_graph_msg_handler, logger) + (secp_ctx, net_graph_msg_handler, chain_monitor, logger) } #[test] fn simple_route_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); let (_, our_id, _, nodes) = get_nodes(&secp_ctx); - // Simple route to 3 via 2 + // Simple route to 2 via 1 + + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 0, 42, Arc::clone(&logger)) { + assert_eq!(err, "Cannot send a payment of 0 msat"); + } else { panic!(); } + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 2); @@ -888,16 +1363,58 @@ mod tests { } #[test] - fn disable_channels_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); + fn invalid_first_hop_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (_, our_id, _, nodes) = get_nodes(&secp_ctx); + + // Simple route to 2 via 1 + + let our_chans = vec![channelmanager::ChannelDetails { + channel_id: [0; 32], + short_channel_id: Some(2), + remote_network_id: our_id, + counterparty_features: InitFeatures::from_le_bytes(vec![0b11]), + channel_value_satoshis: 100000, + user_id: 0, + outbound_capacity_msat: 100000, + inbound_capacity_msat: 100000, + is_live: true, + }]; + + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], Some(&our_chans.iter().collect::>()), &Vec::new(), 100, 42, Arc::clone(&logger)) { + assert_eq!(err, "First hop cannot have our_node_id as a destination."); + } else { panic!(); } + + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths[0].len(), 2); + } + + #[test] + fn htlc_minimum_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); - // // Disable channels 4 and 12 by flags=2 + // Simple route to 2 via 1 + // Should fail if htlc_minimum can't be reached + + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 50_000, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + // Make 0 fee. update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate { chain_hash: genesis_block(Network::Testnet).header.block_hash(), short_channel_id: 4, timestamp: 2, - flags: 2, // to disable + flags: 0, cltv_expiry_delta: 0, htlc_minimum_msat: 0, htlc_maximum_msat: OptionalField::Absent, @@ -905,6 +1422,8 @@ mod tests { fee_proportional_millionths: 0, excess_data: Vec::new() }); + + // Disable other paths update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { chain_hash: genesis_block(Network::Testnet).header.block_hash(), short_channel_id: 12, @@ -917,53 +1436,197 @@ mod tests { fee_proportional_millionths: 0, excess_data: Vec::new() }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 2, // to disable + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 13, + timestamp: 2, + flags: 2, // to disable + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 6, + timestamp: 2, + flags: 2, // to disable + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 7, + timestamp: 2, + flags: 2, // to disable + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); - // If all the channels require some features we don't understand, route should fail - if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 100, 42, Arc::clone(&logger)) { + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 49_999, 42, Arc::clone(&logger)) { assert_eq!(err, "Failed to find a path to the given destination"); } else { panic!(); } - // If we specify a channel to node7, that overrides our local channel view and that gets used - let our_chans = vec![channelmanager::ChannelDetails { - channel_id: [0; 32], - short_channel_id: Some(42), - remote_network_id: nodes[7].clone(), - counterparty_features: InitFeatures::from_le_bytes(vec![0b11]), - channel_value_satoshis: 0, - user_id: 0, - outbound_capacity_msat: 0, - inbound_capacity_msat: 0, - is_live: true, - }]; - let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], Some(&our_chans.iter().collect::>()), &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); + // A payment above the minimum should pass + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 50_000, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 2); - assert_eq!(route.paths[0][0].pubkey, nodes[7]); - assert_eq!(route.paths[0][0].short_channel_id, 42); - assert_eq!(route.paths[0][0].fee_msat, 200); - assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1); - assert_eq!(route.paths[0][0].node_features.le_flags(), &vec![0b11]); // it should also override our view of their features - assert_eq!(route.paths[0][0].channel_features.le_flags(), &Vec::::new()); // No feature flags will meet the relevant-to-channel conversion + // This was a check against final_value_msat. + // Now let's check against amount_to_transfer_over_msat. + // We will be transferring 300_000_000 msat. + // Set minimal HTLC of 200_000_000 msat. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 3, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 200_000_000, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); - assert_eq!(route.paths[0][1].pubkey, nodes[2]); - assert_eq!(route.paths[0][1].short_channel_id, 13); - assert_eq!(route.paths[0][1].fee_msat, 100); - assert_eq!(route.paths[0][1].cltv_expiry_delta, 42); - assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3)); - assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13)); - } + // Second hop only allows to forward 199_999_999 at most, thus not allowing the first hop to + // be used. + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 4, + timestamp: 3, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(199_999_999), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); - #[test] - fn disable_node_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); - let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + // Not possible to send 299_999_999: we first allocate 200_000_000 for the channel#12, + // and then the amount_to_transfer_over_msat over channel#2 is less than our limit. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 199_999_999, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a path to the given destination"); + } else { panic!(); } - // Disable nodes 1, 2, and 8 by requiring unknown feature bits - let mut unknown_features = NodeFeatures::known(); - unknown_features.set_required_unknown_bits(); - add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], unknown_features.clone(), 1); - add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], unknown_features.clone(), 1); - add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], unknown_features.clone(), 1); + // Lift the restriction on the first hop. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 4, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // A payment above the minimum should pass + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 199_999_999, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths[0].len(), 2); + } + + #[test] + fn disable_channels_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // // Disable channels 4 and 12 by flags=2 + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 4, + timestamp: 2, + flags: 2, // to disable + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 2, // to disable + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // If all the channels require some features we don't understand, route should fail + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 100, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a path to the given destination"); + } else { panic!(); } + + // If we specify a channel to node7, that overrides our local channel view and that gets used + let our_chans = vec![channelmanager::ChannelDetails { + channel_id: [0; 32], + short_channel_id: Some(42), + remote_network_id: nodes[7].clone(), + counterparty_features: InitFeatures::from_le_bytes(vec![0b11]), + channel_value_satoshis: 0, + user_id: 0, + outbound_capacity_msat: 0, + inbound_capacity_msat: 0, + is_live: true, + }]; + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], Some(&our_chans.iter().collect::>()), &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths[0].len(), 2); + + assert_eq!(route.paths[0][0].pubkey, nodes[7]); + assert_eq!(route.paths[0][0].short_channel_id, 42); + assert_eq!(route.paths[0][0].fee_msat, 200); + assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1); + assert_eq!(route.paths[0][0].node_features.le_flags(), &vec![0b11]); // it should also override our view of their features + assert_eq!(route.paths[0][0].channel_features.le_flags(), &Vec::::new()); // No feature flags will meet the relevant-to-channel conversion + + assert_eq!(route.paths[0][1].pubkey, nodes[2]); + assert_eq!(route.paths[0][1].short_channel_id, 13); + assert_eq!(route.paths[0][1].fee_msat, 100); + assert_eq!(route.paths[0][1].cltv_expiry_delta, 42); + assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3)); + assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13)); + } + + #[test] + fn disable_node_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // Disable nodes 1, 2, and 8 by requiring unknown feature bits + let mut unknown_features = NodeFeatures::known(); + unknown_features.set_required_unknown_bits(); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], unknown_features.clone(), 1); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], unknown_features.clone(), 1); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], unknown_features.clone(), 1); // If all nodes require some features we don't understand, route should fail if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 100, 42, Arc::clone(&logger)) { @@ -1006,7 +1669,7 @@ mod tests { #[test] fn our_chans_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); let (_, our_id, _, nodes) = get_nodes(&secp_ctx); // Route to 1 via 2 and 3 because our channel to 1 is disabled @@ -1098,10 +1761,32 @@ mod tests { #[test] fn last_hops_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); let (_, our_id, _, nodes) = get_nodes(&secp_ctx); // Simple test across 2, 3, 5, and 4 via a last_hop channel + + // First check that lst hop can't have its source as the payee. + let invalid_last_hop = RouteHint { + src_node_id: nodes[6], + short_channel_id: 8, + fees: RoutingFees { + base_msat: 1000, + proportional_millionths: 0, + }, + cltv_expiry_delta: (8 << 8) | 1, + htlc_minimum_msat: None, + htlc_maximum_msat: None, + }; + + let mut invalid_last_hops = last_hops(&nodes); + invalid_last_hops.push(invalid_last_hop); + { + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, &invalid_last_hops.iter().collect::>(), 100, 42, Arc::clone(&logger)) { + assert_eq!(err, "Last hop cannot have a payee as a source."); + } else { panic!(); } + } + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, &last_hops(&nodes).iter().collect::>(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 5); @@ -1145,7 +1830,7 @@ mod tests { #[test] fn our_chans_last_hop_connect_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); let (_, our_id, _, nodes) = get_nodes(&secp_ctx); // Simple test with outbound channel to 4 to test that last_hops and first_hops connect @@ -1306,4 +1991,1130 @@ mod tests { assert_eq!(route.paths[0][1].node_features.le_flags(), &[0; 0]); // We dont pass flags in from invoices yet assert_eq!(route.paths[0][1].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly } + + #[test] + fn available_amount_while_routing_test() { + // Tests whether we choose the correct available channel amount while routing. + + let (secp_ctx, mut net_graph_msg_handler, chain_monitor, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // We will use a simple single-path route from + // our node to node2 via node0: channels {1, 3}. + + // First disable all other paths. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Make the first channel (#1) very permissive, + // and we will be testing all limits on the second channel. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(1_000_000_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // First, let's see if routing works if we have absolutely no idea about the available amount. + // In this case, it should be set to 250_000 sats. + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 250_000_001, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route an exact amount we have should be fine. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 250_000_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let path = route.paths.last().unwrap(); + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + assert_eq!(path.last().unwrap().fee_msat, 250_000_000); + } + + // Now let's see if routing works if we know only htlc_maximum_msat. + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 3, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(15_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 15_001, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route an exact amount we have should be fine. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 15_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let path = route.paths.last().unwrap(); + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + assert_eq!(path.last().unwrap().fee_msat, 15_000); + } + + // Now let's see if routing works if we know only capacity from the UTXO. + + // We can't change UTXO capacity on the fly, so we'll disable + // the existing channel and add another one with the capacity we need. + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 4, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + let good_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2) + .push_slice(&PublicKey::from_secret_key(&secp_ctx, &privkeys[0]).serialize()) + .push_slice(&PublicKey::from_secret_key(&secp_ctx, &privkeys[2]).serialize()) + .push_opcode(opcodes::all::OP_PUSHNUM_2) + .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh(); + + *chain_monitor.utxo_ret.lock().unwrap() = Ok(TxOut { value: 15, script_pubkey: good_script.clone() }); + net_graph_msg_handler.add_chain_access(Some(chain_monitor)); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 333); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 333, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (3 << 8) | 1, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 333, + timestamp: 1, + flags: 1, + cltv_expiry_delta: (3 << 8) | 2, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 100, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 15_001, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route an exact amount we have should be fine. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 15_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let path = route.paths.last().unwrap(); + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + assert_eq!(path.last().unwrap().fee_msat, 15_000); + } + + // Now let's see if routing chooses htlc_maximum_msat over UTXO capacity. + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 333, + timestamp: 6, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(10_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 10_001, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route an exact amount we have should be fine. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 10_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let path = route.paths.last().unwrap(); + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + assert_eq!(path.last().unwrap().fee_msat, 10_000); + } + } + + #[test] + fn available_liquidity_last_hop_test() { + // Check that available liquidity properly limits the path even when only + // one of the latter hops is limited. + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // Path via {node7, node2, node4} is channels {12, 13, 6, 11}. + // {12, 13, 11} have the capacities of 100, {6} has a capacity of 50. + // Total capacity: 50 sats. + + // Disable other potential paths. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 7, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Limit capacities + + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 6, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(50_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 11, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 60_000, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route 49 sats (just a bit below the capacity). + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 49_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 4); + assert_eq!(path.last().unwrap().pubkey, nodes[3]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 49_000); + } + + { + // Attempt to route an exact amount is also fine + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 50_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 4); + assert_eq!(path.last().unwrap().pubkey, nodes[3]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 50_000); + } + } + + #[test] + fn ignore_fee_first_hop_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50). + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 1_000_000, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(50_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 50_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 50_000); + } + } + + #[test] + fn simple_mpp_route_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // We need a route consisting of 3 paths: + // From our node to node2 via node0, node7, node1 (three paths one hop each). + // To achieve this, the amount being transferred should be around + // the total capacity of these 3 paths. + + // First, we set limits on these (previously unlimited) channels. + // Their aggregate capacity will be 50 + 60 + 180 = 290 sats. + + // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50). + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(50_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via node7 is channels {12, 13}. Limit them to 60 and 60 sats + // (total limit 60). + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(60_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(60_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via node1 is channels {2, 4}. Limit them to 200 and 180 sats + // (total capacity 180 sats). + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(180_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 300_000, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route 250 sats (just a bit below the capacity). + // Our algorithm should provide us with these 3 paths. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 250_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 3); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 250_000); + } + + { + // Attempt to route an exact amount is also fine + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 290_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 3); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 290_000); + } + } + + #[test] + fn long_mpp_route_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // We need a route consisting of 3 paths: + // From our node to node3 via {node0, node2}, {node7, node2, node4} and {node7, node2}. + // Note that these paths overlap (channels 5, 12, 13). + // We will route 300 sats. + // Each path will have 100 sats capacity, those channels which + // are used twice will have 200 sats capacity. + + // Disable other potential paths. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 7, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node0, node2} is channels {1, 3, 5}. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Capacity of 200 sats because this channel will be used by 3rd path as well. + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 5, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node7, node2, node4} is channels {12, 13, 6, 11}. + // Add 100 sats to the capacities of {12, 13}, because these channels + // are also used for 3rd path. 100 sats for the rest. Total capacity: 100 sats. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 6, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 11, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node7, node2} is channels {12, 13, 5}. + // We already limited them to 200 sats (they are used twice for 100 sats). + // Nothing to do here. + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 350_000, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route 300 sats (exact amount we can route). + // Our algorithm should provide us with these 3 paths, 100 sats each. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 300_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 3); + + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.last().unwrap().pubkey, nodes[3]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 300_000); + } + + } + + #[test] + fn mpp_cheaper_route_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // This test checks that if we have two cheaper paths and one more expensive path, + // so that liquidity-wise any 2 of 3 combination is sufficient, + // two cheaper paths will be taken. + // These paths have equal available liquidity. + + // We need a combination of 3 paths: + // From our node to node3 via {node0, node2}, {node7, node2, node4} and {node7, node2}. + // Note that these paths overlap (channels 5, 12, 13). + // Each path will have 100 sats capacity, those channels which + // are used twice will have 200 sats capacity. + + // Disable other potential paths. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 7, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node0, node2} is channels {1, 3, 5}. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Capacity of 200 sats because this channel will be used by 3rd path as well. + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 5, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node7, node2, node4} is channels {12, 13, 6, 11}. + // Add 100 sats to the capacities of {12, 13}, because these channels + // are also used for 3rd path. 100 sats for the rest. Total capacity: 100 sats. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 6, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 1_000, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 11, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node7, node2} is channels {12, 13, 5}. + // We already limited them to 200 sats (they are used twice for 100 sats). + // Nothing to do here. + + { + // Now, attempt to route 180 sats. + // Our algorithm should provide us with these 2 paths. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 180_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 2); + + let mut total_value_transferred_msat = 0; + let mut total_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.last().unwrap().pubkey, nodes[3]); + total_value_transferred_msat += path.last().unwrap().fee_msat; + for hop in path { + total_paid_msat += hop.fee_msat; + } + } + // If we paid fee, this would be higher. + assert_eq!(total_value_transferred_msat, 180_000); + let total_fees_paid = total_paid_msat - total_value_transferred_msat; + assert_eq!(total_fees_paid, 0); + } + } + + #[test] + fn fees_on_mpp_route_test() { + // This test makes sure that MPP algorithm properly takes into account + // fees charged on the channels, by making the fees impactful: + // if the fee is not properly accounted for, the behavior is different. + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // We need a route consisting of 2 paths: + // From our node to node3 via {node0, node2} and {node7, node2, node4}. + // We will route 200 sats, Each path will have 100 sats capacity. + + // This test is not particularly stable: e.g., + // there's a way to route via {node0, node2, node4}. + // It works while pathfinding is deterministic, but can be broken otherwise. + // It's fine to ignore this concern for now. + + // Disable other potential paths. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 7, + timestamp: 2, + flags: 2, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node0, node2} is channels {1, 3, 5}. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 5, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via {node7, node2, node4} is channels {12, 13, 6, 11}. + // All channels should be 100 sats capacity. But for the fee experiment, + // we'll add absolute fee of 150 sats paid for the use channel 6 (paid to node2 on channel 13). + // Since channel 12 allows to deliver only 250 sats to channel 13, channel 13 can transfer only + // 100 sats (and pay 150 sats in fees for the use of channel 6), + // so no matter how large are other channels, + // the whole path will be limited by 100 sats with just these 2 conditions: + // - channel 12 capacity is 250 sats + // - fee for channel 6 is 150 sats + // Let's test this by enforcing these 2 conditions and removing other limits. + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(250_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 6, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 150_000, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 11, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 210_000, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route 200 sats (exact amount we can route). + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[3], None, &Vec::new(), 200_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 2); + + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.last().unwrap().pubkey, nodes[3]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 200_000); + } + + } + + #[test] + fn drop_lowest_channel_mpp_route_test() { + // This test checks that low-capacity channel is dropped when after + // path finding we realize that we found more capacity than we need. + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // We need a route consisting of 3 paths: + // From our node to node2 via node0, node7, node1 (three paths one hop each). + + // The first and the second paths should be sufficient, but the third should be + // cheaper, so that we select it but drop later. + + // First, we set limits on these (previously unlimited) channels. + // Their aggregate capacity will be 50 + 60 + 20 = 130 sats. + + // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50); + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(100_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(50_000), + fee_base_msat: 100, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via node7 is channels {12, 13}. Limit them to 60 and 60 sats (total limit 60); + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 12, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(60_000), + fee_base_msat: 100, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(60_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Path via node1 is channels {2, 4}. Limit them to 20 and 20 sats (total capacity 20 sats). + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 2, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(20_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&net_graph_msg_handler, &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: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(20_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Attempt to route more than available results in a failure. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 150_000, 42, Arc::clone(&logger)) { + assert_eq!(err, "Failed to find a sufficient route to the given destination"); + } else { panic!(); } + } + + { + // Now, attempt to route 125 sats (just a bit below the capacity of 3 channels). + // Our algorithm should provide us with these 3 paths. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 125_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 3); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 125_000); + } + + { + // Attempt to route without the last small cheap channel + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, &Vec::new(), 90_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 2); + let mut total_amount_paid_msat = 0; + for path in &route.paths { + assert_eq!(path.len(), 2); + assert_eq!(path.last().unwrap().pubkey, nodes[2]); + total_amount_paid_msat += path.last().unwrap().fee_msat; + } + assert_eq!(total_amount_paid_msat, 90_000); + } + } + }