X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Frouting%2Frouter.rs;h=548febbd470d440dd39e4f2b6f049c3ce7c3a214;hb=002a5db5b07fd317545d3aa4f1a217cd40b608e2;hp=9f1b60e0d27adf83735dfc02c0f20720e9c67161;hpb=09f37ae89b9417899edd3b47bc7445787e843ebf;p=rust-lightning diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs index 9f1b60e0..548febbd 100644 --- a/lightning/src/routing/router.rs +++ b/lightning/src/routing/router.rs @@ -15,15 +15,16 @@ use bitcoin::secp256k1::key::PublicKey; use ln::channelmanager::ChannelDetails; -use ln::features::{ChannelFeatures, NodeFeatures}; +use ln::features::{ChannelFeatures, InvoiceFeatures, NodeFeatures}; use ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT}; use routing::network_graph::{NetworkGraph, RoutingFees}; use util::ser::{Writeable, Readable}; use util::logger::Logger; -use std::cmp; -use std::collections::{HashMap,BinaryHeap}; -use std::ops::Deref; +use prelude::*; +use alloc::collections::BinaryHeap; +use core::cmp; +use core::ops::Deref; /// A hop in a route #[derive(Clone, PartialEq)] @@ -38,47 +39,23 @@ 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 (might be more than + /// requested if we had to match htlc_minimum_msat). 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. pub cltv_expiry_delta: u32, } -/// (C-not exported) -impl Writeable for Vec { - fn write(&self, writer: &mut W) -> Result<(), ::std::io::Error> { - (self.len() as u8).write(writer)?; - for hop in self.iter() { - hop.pubkey.write(writer)?; - hop.node_features.write(writer)?; - hop.short_channel_id.write(writer)?; - hop.channel_features.write(writer)?; - hop.fee_msat.write(writer)?; - hop.cltv_expiry_delta.write(writer)?; - } - Ok(()) - } -} - -/// (C-not exported) -impl Readable for Vec { - fn read(reader: &mut R) -> Result, DecodeError> { - let hops_count: u8 = Readable::read(reader)?; - let mut hops = Vec::with_capacity(hops_count as usize); - for _ in 0..hops_count { - hops.push(RouteHop { - pubkey: Readable::read(reader)?, - node_features: Readable::read(reader)?, - short_channel_id: Readable::read(reader)?, - channel_features: Readable::read(reader)?, - fee_msat: Readable::read(reader)?, - cltv_expiry_delta: Readable::read(reader)?, - }); - } - Ok(hops) - } -} +impl_writeable_tlv_based!(RouteHop, { + (0, pubkey, required), + (2, node_features, required), + (4, short_channel_id, required), + (6, channel_features, required), + (8, fee_msat, required), + (10, cltv_expiry_delta, required), +}); /// A route directs a payment from the sender (us) to the recipient. If the recipient supports MPP, /// it can take multiple paths. Each path is composed of one or more hops through the network. @@ -93,30 +70,49 @@ pub struct Route { pub paths: Vec>, } +const SERIALIZATION_VERSION: u8 = 1; +const MIN_SERIALIZATION_VERSION: u8 = 1; + impl Writeable for Route { fn write(&self, writer: &mut W) -> Result<(), ::std::io::Error> { + write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION); (self.paths.len() as u64).write(writer)?; for hops in self.paths.iter() { - hops.write(writer)?; + (hops.len() as u8).write(writer)?; + for hop in hops.iter() { + hop.write(writer)?; + } } + write_tlv_fields!(writer, {}); Ok(()) } } impl Readable for Route { fn read(reader: &mut R) -> Result { + let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION); let path_count: u64 = Readable::read(reader)?; let mut paths = Vec::with_capacity(cmp::min(path_count, 128) as usize); for _ in 0..path_count { - paths.push(Readable::read(reader)?); + let hop_count: u8 = Readable::read(reader)?; + let mut hops = Vec::with_capacity(hop_count as usize); + for _ in 0..hop_count { + hops.push(Readable::read(reader)?); + } + paths.push(hops); } + read_tlv_fields!(reader, {}); Ok(Route { paths }) } } -/// A channel descriptor which provides a last-hop route to get_route -#[derive(Clone)] -pub struct RouteHint { +/// A list of hops along a payment path terminating with a channel to the recipient. +#[derive(Eq, PartialEq, Debug, Clone)] +pub struct RouteHint(pub Vec); + +/// A channel descriptor for a hop along a payment path. +#[derive(Eq, PartialEq, Debug, Clone)] +pub struct RouteHintHop { /// The node_id of the non-target end of the route pub src_node_id: PublicKey, /// The short_channel_id of this channel @@ -126,7 +122,9 @@ pub struct RouteHint { /// The difference in CLTV values between this node and the next node. pub cltv_expiry_delta: u16, /// The minimum value, in msat, which must be relayed to the next hop. - pub htlc_minimum_msat: u64, + pub htlc_minimum_msat: Option, + /// The maximum value in msat available for routing with a single HTLC. + pub htlc_maximum_msat: Option, } #[derive(Eq, PartialEq)] @@ -134,12 +132,22 @@ 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, + /// The effective htlc_minimum_msat at this hop. If a later hop on the path had a higher HTLC + /// minimum, we use it, plus the fees required at each earlier hop to meet it. + path_htlc_minimum_msat: u64, } impl cmp::Ord for RouteGraphNode { fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering { - other.lowest_fee_to_peer_through_node.cmp(&self.lowest_fee_to_peer_through_node) - .then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize())) + let other_score = cmp::max(other.lowest_fee_to_peer_through_node, other.path_htlc_minimum_msat); + let self_score = cmp::max(self.lowest_fee_to_peer_through_node, self.path_htlc_minimum_msat); + other_score.cmp(&self_score).then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize())) } } @@ -152,31 +160,197 @@ impl cmp::PartialOrd for RouteGraphNode { struct DummyDirectionalChannelInfo { cltv_expiry_delta: u32, htlc_minimum_msat: u64, + htlc_maximum_msat: Option, 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, Debug)] +struct PathBuildingHop<'a> { + // The RouteHintHop fields which will eventually be used if this hop is used in a final Route. + // Note that node_features is calculated separately after our initial graph walk. + pubkey: PublicKey, + short_channel_id: u64, + channel_features: &'a ChannelFeatures, + fee_msat: u64, + cltv_expiry_delta: u32, + + /// 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, + /// This is useful for update_value_and_recompute_fees to make sure + /// we don't fall below the minimum. Should not be updated manually and + /// generally should not be accessed. + htlc_minimum_msat: u64, + /// A mirror of the same field in RouteGraphNode. Note that this is only used during the graph + /// walk and may be invalid thereafter. + path_htlc_minimum_msat: u64, + /// If we've already processed a node as the best node, we shouldn't process it again. Normally + /// we'd just ignore it if we did as all channels would have a higher new fee, but because we + /// may decrease the amounts in use as we walk the graph, the actual calculated fee may + /// decrease as well. Thus, we have to explicitly track which nodes have been processed and + /// avoid processing them again. + was_processed: bool, + #[cfg(any(test, feature = "fuzztarget"))] + // In tests, we apply further sanity checks on cases where we skip nodes we already processed + // to ensure it is specifically in cases where the fee has gone down because of a decrease in + // value_contribution_msat, which requires tracking it here. See comments below where it is + // used for more info. + value_contribution_msat: u64, +} + +// 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<'a> { + hops: Vec<(PathBuildingHop<'a>, NodeFeatures)>, +} + +impl<'a> PaymentPath<'a> { + // 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().0.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.fee_msat; + } + } + return result; + } + + // If the amount transferred by the path is updated, the fees should be adjusted. Any other way + // to change fees may result in an inconsistency. + // + // Sometimes we call this function right after constructing a path which is inconsistent in + // that it the value being transferred has decreased while we were doing path finding, leading + // to the fees being paid not lining up with the actual limits. + // + // Note that this function is not aware of the available_liquidity limit, and thus does not + // support increasing the value being transferred. + fn update_value_and_recompute_fees(&mut self, value_msat: u64) { + assert!(value_msat <= self.hops.last().unwrap().0.fee_msat); + + let mut total_fee_paid_msat = 0 as u64; + for i in (0..self.hops.len()).rev() { + let last_hop = i == self.hops.len() - 1; + + // For non-last-hop, this value will represent the fees paid on the current hop. It + // will consist of the fees for the use of the next hop, and extra fees to match + // htlc_minimum_msat of the current channel. Last hop is handled separately. + let mut cur_hop_fees_msat = 0; + if !last_hop { + cur_hop_fees_msat = self.hops.get(i + 1).unwrap().0.hop_use_fee_msat; + } + + let mut cur_hop = &mut self.hops.get_mut(i).unwrap().0; + cur_hop.next_hops_fee_msat = total_fee_paid_msat; + // Overpay in fees if we can't save these funds due to htlc_minimum_msat. + // We try to account for htlc_minimum_msat in scoring (add_entry!), so that nodes don't + // set it too high just to maliciously take more fees by exploiting this + // match htlc_minimum_msat logic. + let mut cur_hop_transferred_amount_msat = total_fee_paid_msat + value_msat; + if let Some(extra_fees_msat) = cur_hop.htlc_minimum_msat.checked_sub(cur_hop_transferred_amount_msat) { + // Note that there is a risk that *previous hops* (those closer to us, as we go + // payee->our_node here) would exceed their htlc_maximum_msat or available balance. + // + // This might make us end up with a broken route, although this should be super-rare + // in practice, both because of how healthy channels look like, and how we pick + // channels in add_entry. + // Also, this can't be exploited more heavily than *announce a free path and fail + // all payments*. + cur_hop_transferred_amount_msat += extra_fees_msat; + total_fee_paid_msat += extra_fees_msat; + cur_hop_fees_msat += extra_fees_msat; + } + + if last_hop { + // Final hop is a special case: it usually has just value_msat (by design), but also + // it still could overpay for the htlc_minimum_msat. + cur_hop.fee_msat = cur_hop_transferred_amount_msat; + } else { + // Propagate updated fees for the use of the channels to one hop back, where they + // will be actually paid (fee_msat). The last hop is handled above separately. + cur_hop.fee_msat = cur_hop_fees_msat; + } + + // Fee for the use of the current hop which will be deducted on the previous hop. + // Irrelevant for the first hop, as it doesn't have the previous hop, and the use of + // this channel is free for us. + if i != 0 { + if let Some(new_fee) = compute_fees(cur_hop_transferred_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!(); + } + } + } + } +} + +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). +/// +/// If the payee provided features in their invoice, they should be provided via payee_features. +/// Without this, MPP will only be used if the payee's features are available in the network graph. /// -/// Extra routing hops between known nodes and the target will be used if they are included in -/// last_hops. +/// Private routing paths between a public node and the target may be included in `last_hops`. +/// Currently, only the last hop in each path is considered. /// /// 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, payee_features: Option, 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}); } @@ -184,8 +358,73 @@ 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 - // plus the minimum per-HTLC fee to get from it to another node (aka "shitty A*"). + if final_value_msat == 0 { + return Err(LightningError{err: "Cannot send a payment of 0 msat".to_owned(), action: ErrorAction::IgnoreError}); + } + + let last_hops = last_hops.iter().filter_map(|hops| hops.0.last()).collect::>(); + for last_hop in last_hops.iter() { + 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 pseudo-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 pseudo-A*"). + // + // We are not a faithful Dijkstra's implementation because we can change values which impact + // earlier nodes while processing later nodes. Specifically, if we reach a channel with a lower + // liquidity limit (via htlc_maximum_msat, on-chain capacity or assumed liquidity limits) then + // the value we are currently attempting to send over a path, we simply reduce the value being + // sent along the path for any hops after that channel. This may imply that later fees (which + // we've already tabulated) are lower because a smaller value is passing through the channels + // (and the proportional fee is thus lower). There isn't a trivial way to recalculate the + // channels which were selected earlier (and which may still be used for other paths without a + // lower liquidity limit), so we simply accept that some liquidity-limited paths may be + // de-preferenced. + // + // One potentially problematic case for this algorithm would be if there are many + // liquidity-limited paths which are liquidity-limited near the destination (ie early in our + // graph walking), we may never find a path which is not liquidity-limited and has lower + // proportional fee (and only lower absolute fee when considering the ultimate value sent). + // Because we only consider paths with at least 5% of the total value being sent, the damage + // from such a case should be limited, however this could be further reduced in the future by + // calculating fees on the amount we wish to route over a path, ie ignoring the liquidity + // limits for the purposes of fee calculation. + // + // Alternatively, we could store more detailed path information in the heap (targets, below) + // and index the best-path map (dist, below) by node *and* HTLC limits, however that would blow + // up the runtime significantly both algorithmically (as we'd traverse nodes multiple times) + // and practically (as we would need to store dynamically-allocated path information in heap + // objects, increasing malloc traffic and indirect memory access significantly). Further, the + // results of such an algorithm would likely be biased towards lower-value paths. + // + // Further, we could return to a faithful Dijkstra's algorithm by rejecting paths with limits + // outside of our current search value, running a path search more times to gather candidate + // paths at different values. While this may be acceptable, further path searches may increase + // runtime for little gain. Specifically, the current algorithm rather efficiently explores the + // graph for candidate paths, calculating the maximum value which can realistically be sent at + // the same time, remaining generic across different payment values. + // // 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 // one. @@ -193,140 +432,393 @@ pub fn get_route(our_node_id: &PublicKey, network: &NetworkGraph, targ let dummy_directional_info = DummyDirectionalChannelInfo { // used for first_hops routes cltv_expiry_delta: 0, htlc_minimum_msat: 0, + htlc_maximum_msat: None, fees: RoutingFees { base_msat: 0, proportional_millionths: 0, } }; - 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()); - - let mut first_hop_targets = HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 }); + // Allow MPP only if we have a features set from somewhere that indicates the payee supports + // it. If the payee supports it they're supposed to include it in the invoice, so that should + // work reliably. + let allow_mpp = if let Some(features) = &payee_features { + features.supports_basic_mpp() + } else if let Some(node) = network.get_nodes().get(&payee) { + if let Some(node_info) = node.announcement_info.as_ref() { + node_info.features.supports_basic_mpp() + } else { false } + } else { false }; + + // 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<_, (_, ChannelFeatures, _, NodeFeatures)> = + 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 { - return Ok(Route { - paths: vec![vec![RouteHop { - pubkey: chan.remote_network_id, - node_features: chan.counterparty_features.to_context(), - short_channel_id, - channel_features: chan.counterparty_features.to_context(), - fee_msat: final_value_msat, - cltv_expiry_delta: final_cltv, - }]], - }); + if chan.counterparty.node_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())); + first_hop_targets.insert(chan.counterparty.node_id, (short_channel_id, chan.counterparty.features.to_context(), chan.outbound_capacity_msat, chan.counterparty.features.to_context())); } if first_hop_targets.is_empty() { return Err(LightningError{err: "Cannot route when there are no outbound routes away from us".to_owned(), action: ErrorAction::IgnoreError}); } } + let empty_channel_features = ChannelFeatures::empty(); + + // The main heap containing all candidate next-hops sorted by their score (max(A* fee, + // htlc_minimum)). Ideally this would be a heap which allowed cheap score reduction instead of + // adding duplicate entries when we find a better path to a given node. + let mut targets = BinaryHeap::new(); + + // Map from node_id to information about the best current path to that node, including feerate + // information. + let mut dist = HashMap::with_capacity(network.get_nodes().len()); + + // During routing, if we ignore a path due to an htlc_minimum_msat limit, we set this, + // indicating that we may wish to try again with a higher value, potentially paying to meet an + // htlc_minimum with extra fees while still finding a cheaper path. + let mut hit_minimum_limit; + + // When arranging a route, we select multiple paths so that we can make a multi-path payment. + // We start with a path_value of the exact amount we want, and if that generates a route we may + // return it immediately. Otherwise, we don't stop searching for paths until we have 3x the + // amount we want in total across paths, selecting the best subset at the end. + const ROUTE_CAPACITY_PROVISION_FACTOR: u64 = 3; + let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64; + let mut path_value_msat = final_value_msat; + + // 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 (except for `outbound_capacity_msat` in `first_hops`). + let mut bookkeeped_channels_liquidity_available_msat = HashMap::with_capacity(network.get_nodes().len()); + + // 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; + + log_trace!(logger, "Building path from {} (payee) to {} (us/payer) for value {} msat.", payee, our_node_id, final_value_msat); + 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, $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 = $starting_fee_msat as u64; - let hm_entry = dist.entry(&$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; + // $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. + // Returns whether this channel caused an update to `targets`. + ( $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, $next_hops_path_htlc_minimum_msat: expr ) => { { + // We "return" whether we updated the path at the end, via this: + let mut did_add_update_path_to_src_node = false; + // 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(available_msat) = initial_liquidity_available_msat { + initial_liquidity_available_msat = Some(cmp::min(available_msat, htlc_maximum_msat)); + } else { + initial_liquidity_available_msat = Some(htlc_maximum_msat); } - (u64::max_value(), - fee_base_msat, - fee_proportional_millionths, - RouteHop { + } + + 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) + // or 100% if we're not allowed to do multipath payments. + let minimal_value_contribution_msat: u64 = if allow_mpp { + (recommended_value_msat - already_collected_value_msat + 19) / 20 + } else { + final_value_msat + }; + // 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!(), + }; + #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains + let over_path_minimum_msat = amount_to_transfer_over_msat >= $directional_info.htlc_minimum_msat && + amount_to_transfer_over_msat >= $next_hops_path_htlc_minimum_msat; + + // If HTLC minimum is larger than the amount we're going to transfer, we shouldn't + // bother considering this channel. + // Since we're choosing amount_to_transfer_over_msat as maximum possible, it can + // be only reduced later (not increased), so this channel should just be skipped + // as not sufficient. + if !over_path_minimum_msat { + hit_minimum_limit = true; + } else if contributes_sufficient_value { + // Note that low contribution here (limited by available_liquidity_msat) + // might violate htlc_minimum_msat on the hops which are next along the + // payment path (upstream to the payee). To avoid that, we recompute path + // path fees knowing the final path contribution after constructing it. + let path_htlc_minimum_msat = match compute_fees($next_hops_path_htlc_minimum_msat, $directional_info.fees) + .map(|fee_msat| fee_msat.checked_add($next_hops_path_htlc_minimum_msat)) { + Some(Some(value_msat)) => cmp::max(value_msat, $directional_info.htlc_minimum_msat), + _ => u64::max_value() + }; + let hm_entry = dist.entry(&$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 { pubkey: $dest_node_id.clone(), - node_features: NodeFeatures::empty(), short_channel_id: 0, - channel_features: $chan_features.clone(), + channel_features: $chan_features, fee_msat: 0, cltv_expiry_delta: 0, - }, - ) - }); - 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(); + 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(), + htlc_minimum_msat: $directional_info.htlc_minimum_msat, + path_htlc_minimum_msat, + was_processed: false, + #[cfg(any(test, feature = "fuzztarget"))] + value_contribution_msat, + } + }); + + #[allow(unused_mut)] // We only use the mut in cfg(test) + let mut should_process = !old_entry.was_processed; + #[cfg(any(test, feature = "fuzztarget"))] + { + // In test/fuzzing builds, we do extra checks to make sure the skipping + // of already-seen nodes only happens in cases we expect (see below). + if !should_process { should_process = true; } } - } - 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, + + if should_process { + 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; + // When calculating the lowest inbound fees to a node, we + // calculate fees here not based on the actual value we think + // will flow over this channel, but on the minimum value that + // we'll accept flowing over it. The minimum accepted value + // is a constant through each path collection run, ensuring + // consistent basis. Otherwise we may later find a + // different path to the source node that is more expensive, + // but which we consider to be cheaper because we are capacity + // constrained and the relative fee becomes lower. + match compute_fees(minimal_value_contribution_msat, old_entry.src_lowest_inbound_fees) + .map(|a| a.checked_add(total_fee_msat)) { + Some(Some(v)) => { + total_fee_msat = v; + }, + _ => { + total_fee_msat = u64::max_value(); + } + }; + } + } + } + + 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, + path_htlc_minimum_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). + // Also, consider that htlc_minimum_msat_difference, because we might end up + // paying it. Consider the following exploit: + // we use 2 paths to transfer 1.5 BTC. One of them is 0-fee normal 1 BTC path, + // and for the other one we picked a 1sat-fee path with htlc_minimum_msat of + // 1 BTC. Now, since the latter is more expensive, we gonna try to cut it + // by 0.5 BTC, but then match htlc_minimum_msat by paying a fee of 0.5 BTC + // to this channel. + // Ideally the scoring could be smarter (e.g. 0.5*htlc_minimum_msat here), + // but it may require additional tracking - we don't want to double-count + // the fees included in $next_hops_path_htlc_minimum_msat, but also + // can't use something that may decrease on future hops. + let old_cost = cmp::max(old_entry.total_fee_msat, old_entry.path_htlc_minimum_msat); + let new_cost = cmp::max(total_fee_msat, path_htlc_minimum_msat); + + if !old_entry.was_processed && new_cost < old_cost { + 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.pubkey = $dest_node_id.clone(); + old_entry.short_channel_id = $chan_id.clone(); + old_entry.channel_features = $chan_features; + old_entry.fee_msat = 0; // This value will be later filled with hop_use_fee_msat of the following channel + old_entry.cltv_expiry_delta = $directional_info.cltv_expiry_delta as u32; + old_entry.channel_fees = $directional_info.fees; + old_entry.htlc_minimum_msat = $directional_info.htlc_minimum_msat; + old_entry.path_htlc_minimum_msat = path_htlc_minimum_msat; + #[cfg(any(test, feature = "fuzztarget"))] + { + old_entry.value_contribution_msat = value_contribution_msat; + } + did_add_update_path_to_src_node = true; + } else if old_entry.was_processed && new_cost < old_cost { + #[cfg(any(test, feature = "fuzztarget"))] + { + // If we're skipping processing a node which was previously + // processed even though we found another path to it with a + // cheaper fee, check that it was because the second path we + // found (which we are processing now) has a lower value + // contribution due to an HTLC minimum limit. + // + // e.g. take a graph with two paths from node 1 to node 2, one + // through channel A, and one through channel B. Channel A and + // B are both in the to-process heap, with their scores set by + // a higher htlc_minimum than fee. + // Channel A is processed first, and the channels onwards from + // node 1 are added to the to-process heap. Thereafter, we pop + // Channel B off of the heap, note that it has a much more + // restrictive htlc_maximum_msat, and recalculate the fees for + // all of node 1's channels using the new, reduced, amount. + // + // This would be bogus - we'd be selecting a higher-fee path + // with a lower htlc_maximum_msat instead of the one we'd + // already decided to use. + debug_assert!(path_htlc_minimum_msat < old_entry.path_htlc_minimum_msat); + debug_assert!(value_contribution_msat < old_entry.value_contribution_msat); + } + } } } } } - }; + did_add_update_path_to_src_node + } } } + let empty_node_features = NodeFeatures::empty(); + // 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, $fee_to_target_msat: expr ) => { - if first_hops.is_some() { - if let Some(&(ref first_hop, ref features)) = first_hop_targets.get(&$node_id) { - add_entry!(first_hop, *our_node_id, $node_id, dummy_directional_info, features.to_context(), $fee_to_target_msat); + ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr ) => { + let skip_node = if let Some(elem) = dist.get_mut($node_id) { + let was_processed = elem.was_processed; + elem.was_processed = true; + was_processed + } else { + // Entries are added to dist in add_entry!() when there is a channel from a node. + // Because there are no channels from payee, it will not have a dist entry at this point. + // If we're processing any other node, it is always be the result of a channel from it. + assert_eq!($node_id, payee); + false + }; + + if !skip_node { + if first_hops.is_some() { + if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&$node_id) { + add_entry!(first_hop, *our_node_id, $node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat); + } } - } - let features; - if let Some(node_info) = $node.announcement_info.as_ref() { - features = node_info.features.clone(); - } else { - features = NodeFeatures::empty(); - } + let features = if let Some(node_info) = $node.announcement_info.as_ref() { + &node_info.features + } else { + &empty_node_features + }; - if !features.requires_unknown_bits() { - for chan_id in $node.channels.iter() { - let chan = network.get_channels().get(chan_id).unwrap(); - if !chan.features.requires_unknown_bits() { - if chan.node_one == *$node_id { - // ie $node is one, ie next hop in A* is two, via the two_to_one channel - 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.features, $fee_to_target_msat); + if !features.requires_unknown_bits() { + for chan_id in $node.channels.iter() { + let chan = network.get_channels().get(chan_id).unwrap(); + if !chan.features.requires_unknown_bits() { + if chan.node_one == *$node_id { + // ie $node is one, ie next hop in A* is two, via the two_to_one channel + 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, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat); + } } } - } - } else { - 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.features, $fee_to_target_msat); + } else { + 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, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat); + } } } - } } } @@ -335,91 +827,357 @@ 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(); + hit_minimum_limit = false; + + // If first hop is a private channel and the only way to reach the payee, this is the only + // place where it could be added. + if first_hops.is_some() { + if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&payee) { + add_entry!(first_hop, *our_node_id, payee, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0); + } + } - 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, 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. - add_entry!(hop.short_channel_id, hop.src_node_id, target, hop, ChannelFeatures::empty(), 0); + // 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, path_value_msat, 0); + }, } - } - 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(); + // 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 = + // Only add the last hop to our candidate set if either we have a direct channel or + // they are in the regular network graph. + first_hop_targets.get(&hop.src_node_id).is_some() || + 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, + }; + if add_entry!(hop.short_channel_id, hop.src_node_id, payee, directional_info, None::, &empty_channel_features, 0, path_value_msat, 0) { + // If this hop connects to a node with which we have a direct channel, + // ignore the network graph and, if the last hop was added, add our + // direct channel to the candidate set. + // + // Note that we *must* check if the last hop was added as `add_entry` + // always assumes that the third argument is a node to which we have a + // path. + if let Some(&(ref first_hop, ref features, ref outbound_capacity_msat, _)) = first_hop_targets.get(&hop.src_node_id) { + add_entry!(first_hop, *our_node_id , hop.src_node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0); + } + } + } + } + + log_trace!(logger, "Starting main path collection loop with {} nodes pre-filled from first/last hops.", targets.len()); + + // 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, path_htlc_minimum_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(), NodeFeatures::empty())); + + 'path_walk: loop { + if let Some(&(_, _, _, ref features)) = first_hop_targets.get(&ordered_hops.last().unwrap().0.pubkey) { + ordered_hops.last_mut().unwrap().1 = features.clone(); + } else if let Some(node) = network.get_nodes().get(&ordered_hops.last().unwrap().0.pubkey) { + if let Some(node_info) = node.announcement_info.as_ref() { + ordered_hops.last_mut().unwrap().1 = node_info.features.clone(); + } else { + ordered_hops.last_mut().unwrap().1 = 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().0.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().0.pubkey == *payee { + break 'path_walk; + } + + new_entry = match dist.remove(&ordered_hops.last().unwrap().0.pubkey) { + Some(payment_hop) => payment_hop, + // We can't arrive at None because, if we ever add an entry to targets, + // we also fill in the entry in dist (see add_entry!). + None => unreachable!(), + }; + // 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().0.fee_msat = new_entry.hop_use_fee_msat; + ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = new_entry.cltv_expiry_delta; + ordered_hops.push((new_entry.clone(), NodeFeatures::empty())); + } + ordered_hops.last_mut().unwrap().0.fee_msat = value_contribution_msat; + ordered_hops.last_mut().unwrap().0.hop_use_fee_msat = 0; + ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = final_cltv; + + log_trace!(logger, "Found a path back to us from the target with {} hops contributing up to {} msat: {:?}", + ordered_hops.len(), value_contribution_msat, ordered_hops); + + let mut payment_path = PaymentPath {hops: ordered_hops}; + + // We could have possibly constructed a slightly inconsistent path: since we reduce + // value being transferred along the way, we could have violated htlc_minimum_msat + // on some channels we already passed (assuming dest->source direction). Here, we + // recompute the fees again, so that if that's the case, we match the currently + // underpaid htlc_minimum_msat with fees. + payment_path.update_value_and_recompute_fees(cmp::min(value_contribution_msat, final_value_msat)); + + // 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. + let mut prevented_redundant_path_selection = false; + for (payment_hop, _) in payment_path.hops.iter() { + let channel_liquidity_available_msat = bookkeeped_channels_liquidity_available_msat.get_mut(&payment_hop.short_channel_id).unwrap(); + let mut spent_on_hop_msat = value_contribution_msat; + let next_hops_fee_msat = payment_hop.next_hops_fee_msat; + spent_on_hop_msat += next_hops_fee_msat; + if spent_on_hop_msat == *channel_liquidity_available_msat { + // If this path used all of this channel's available liquidity, we know + // this path will not be selected again in the next loop iteration. + prevented_redundant_path_selection = true; + } + *channel_liquidity_available_msat -= spent_on_hop_msat; + } + if !prevented_redundant_path_selection { + // If we weren't capped by hitting a liquidity limit on a channel in the path, + // we'll probably end up picking the same path again on the next iteration. + // Decrease the available liquidity of a hop in the middle of the path. + let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.short_channel_id; + log_trace!(logger, "Disabling channel {} for future path building iterations to avoid duplicates.", victim_scid); + let victim_liquidity = bookkeeped_channels_liquidity_available_msat.get_mut(&victim_scid).unwrap(); + *victim_liquidity = 0; } - if res.last().unwrap().pubkey == *target { + + // 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; + } + + // If we found a path back to the payee, we shouldn't try to process it again. This is + // the equivalent of the `elem.was_processed` check in + // add_entries_to_cheapest_to_target_node!() (see comment there for more info). + if pubkey == *payee { continue 'path_construction; } + + // 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, path_htlc_minimum_msat); + }, + } + } + + if !allow_mpp { + // If we don't support MPP, no use trying to gather more value ever. + break 'paths_collection; + } + + // Step (3). + // Stop either when the recommended value is reached or if no new path was found in this + // iteration. + // In the latter case, making another path finding attempt won't help, + // because we deterministically terminated the search due to low liquidity. + if already_collected_value_msat >= recommended_value_msat || !found_new_path { + log_trace!(logger, "Have now collected {} msat (seeking {} msat) in paths. Last path loop {} a new path.", + already_collected_value_msat, recommended_value_msat, if found_new_path { "found" } else { "did not find" }); + break 'paths_collection; + } else if found_new_path && already_collected_value_msat == final_value_msat && payment_paths.len() == 1 { + // Further, if this was our first walk of the graph, and we weren't limited by an + // htlc_minimum_msat, return immediately because this path should suffice. If we were + // limited by an htlc_minimum_msat value, find another path with a higher value, + // potentially allowing us to pay fees to meet the htlc_minimum on the new path while + // still keeping a lower total fee than this path. + if !hit_minimum_limit { + log_trace!(logger, "Collected exactly our payment amount on the first pass, without hitting an htlc_minimum_msat limit, exiting."); + break 'paths_collection; + } + log_trace!(logger, "Collected our payment amount on the first pass, but running again to collect extra paths with a potentially higher limit."); + path_value_msat = recommended_value_msat; + } + } + + // 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. And also htlc_minimum_msat. + 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; } - 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); + assert!(cur_route.len() > 0); + + // Step (7). + // Now, substract the overpaid value from the most-expensive path. + // TODO: this could also be optimized by also sorting by feerate_per_sat_routed, + // so that the sender pays less fees overall. And also htlc_minimum_msat. + cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.channel_fees.proportional_millionths as u64).sum::() }); + let expensive_payment_path = cur_route.first_mut().unwrap(); + // We already dropped all the small channels above, meaning all the + // remaining channels are larger than remaining overpaid_value_msat. + // Thus, this can't be negative. + let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat; + expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat); + break; } - 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); } + drawn_routes.push(cur_route); + } - match network.get_nodes().get(&pubkey) { - None => {}, - Some(node) => { - add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node); - }, + // 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, node_features)| { + RouteHop { + pubkey: payment_hop.pubkey, + node_features: node_features.clone(), + short_channel_id: payment_hop.short_channel_id, + channel_features: payment_hop.channel_features.clone(), + fee_msat: payment_hop.fee_msat, + cltv_expiry_delta: payment_hop.cltv_expiry_delta, + } + }).collect()); + } + + if let Some(features) = &payee_features { + for path in selected_paths.iter_mut() { + path.last_mut().unwrap().node_features = features.to_context(); } } - Err(LightningError{err: "Failed to find a path to the given destination".to_owned(), action: ErrorAction::IgnoreError}) + let route = Route { paths: selected_paths }; + log_info!(logger, "Got route to {}: {}", payee, log_route!(route)); + Ok(route) } #[cfg(test)] mod tests { - use routing::router::{get_route, RouteHint, RoutingFees}; + use routing::router::{get_route, Route, RouteHint, RouteHintHop, RoutingFees}; use routing::network_graph::{NetworkGraph, NetGraphMsgHandler}; - use ln::features::{ChannelFeatures, InitFeatures, NodeFeatures}; + use chain::transaction::OutPoint; + use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures}; use ln::msgs::{ErrorAction, LightningError, OptionalField, UnsignedChannelAnnouncement, ChannelAnnouncement, RoutingMessageHandler, NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate}; use ln::channelmanager; @@ -430,13 +1188,41 @@ 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; use bitcoin::secp256k1::key::{PublicKey,SecretKey}; use bitcoin::secp256k1::{Secp256k1, All}; - use std::sync::Arc; + use prelude::*; + use sync::{self, Arc}; + + fn get_channel_details(short_channel_id: Option, node_id: PublicKey, + features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails { + channelmanager::ChannelDetails { + channel_id: [0; 32], + counterparty: channelmanager::ChannelCounterparty { + features, + node_id, + unspendable_punishment_reserve: 0, + forwarding_info: None, + }, + funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }), + short_channel_id, + channel_value_satoshis: 0, + user_id: 0, + outbound_capacity_msat, + inbound_capacity_msat: 42, + unspendable_punishment_reserve: None, + confirmations_required: None, + force_close_spend_delay: None, + is_outbound: true, is_funding_locked: true, + is_usable: true, is_public: true, + } + } // Using the same keys for LN and BTC ids fn add_channel(net_graph_msg_handler: &NetGraphMsgHandler, Arc>, secp_ctx: &Secp256k1, node_1_privkey: &SecretKey, @@ -478,12 +1264,10 @@ 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); @@ -537,9 +1321,10 @@ mod tests { } } - fn build_graph() -> (Secp256k1, NetGraphMsgHandler, std::sync::Arc>, std::sync::Arc) { + fn build_graph() -> (Secp256k1, NetGraphMsgHandler, sync::Arc>, sync::Arc, 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: // @@ -836,16 +1621,21 @@ 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 - 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(); + // 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, 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, None, &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 2); assert_eq!(route.paths[0][0].pubkey, nodes[1]); @@ -864,14 +1654,33 @@ 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![get_channel_details(Some(2), our_id, InitFeatures::from_le_bytes(vec![0b11]), 100000)]; + + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, 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, 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 - update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate { + // Simple route to 2 via 1 + + // 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: 4, + short_channel_id: 12, timestamp: 2, flags: 2, // to disable cltv_expiry_delta: 0, @@ -881,9 +1690,45 @@ mod tests { fee_proportional_millionths: 0, excess_data: Vec::new() }); - update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate { chain_hash: genesis_block(Network::Testnet).header.block_hash(), - short_channel_id: 12, + 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, @@ -894,26 +1739,238 @@ mod tests { 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)) { + // Check against amount_to_transfer_over_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() + }); + + // 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() + }); + + // Not possible to send 199_999_999, because the minimum on channel=2 is 200_000_000. + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, None, &Vec::new(), 199_999_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(); - assert_eq!(route.paths[0].len(), 2); - + // 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, None, &Vec::new(), 199_999_999, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths[0].len(), 2); + } + + #[test] + fn htlc_minimum_overpay_test() { + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // A route to node#2 via two paths. + // One path allows transferring 35-40 sats, another one also allows 35-40 sats. + // Thus, they can't send 60 without overpaying. + 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: 35_000, + htlc_maximum_msat: OptionalField::Present(40_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: 3, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 35_000, + htlc_maximum_msat: OptionalField::Present(40_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + // Make 0 fee. + 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[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::Absent, + fee_base_msat: 0, + 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: 1, + timestamp: 3, + 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() + }); + + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], + Some(InvoiceFeatures::known()), None, &Vec::new(), 60_000, 42, Arc::clone(&logger)).unwrap(); + // Overpay fees to hit htlc_minimum_msat. + let overpaid_fees = route.paths[0][0].fee_msat + route.paths[1][0].fee_msat; + // TODO: this could be better balanced to overpay 10k and not 15k. + assert_eq!(overpaid_fees, 15_000); + + // Now, test that if there are 2 paths, a "cheaper" by fee path wouldn't be prioritized + // while taking even more fee to match htlc_minimum_msat. + 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: 4, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 65_000, + htlc_maximum_msat: OptionalField::Present(80_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: 2, + timestamp: 3, + 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[1], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 4, + timestamp: 4, + flags: 0, + cltv_expiry_delta: 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 100_000, + excess_data: Vec::new() + }); + + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], + Some(InvoiceFeatures::known()), None, &Vec::new(), 60_000, 42, Arc::clone(&logger)).unwrap(); + // Fine to overpay for htlc_minimum_msat if it allows us to save fee. + assert_eq!(route.paths.len(), 1); + assert_eq!(route.paths[0][0].short_channel_id, 12); + let fees = route.paths[0][0].fee_msat; + assert_eq!(fees, 5_000); + + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], + Some(InvoiceFeatures::known()), None, &Vec::new(), 50_000, 42, Arc::clone(&logger)).unwrap(); + // Not fine to overpay for htlc_minimum_msat if it requires paying more than fee on + // the other channel. + assert_eq!(route.paths.len(), 1); + assert_eq!(route.paths[0][0].short_channel_id, 2); + let fees = route.paths[0][0].fee_msat; + assert_eq!(fees, 5_000); + } + + #[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, 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![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)]; + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, 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); @@ -931,34 +1988,23 @@ mod tests { #[test] fn disable_node_test() { - let (secp_ctx, net_graph_msg_handler, logger) = build_graph(); + 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(); + let unknown_features = NodeFeatures::known().set_unknown_feature_required(); 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)) { + if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, 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(); + let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)]; + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, 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]); @@ -982,11 +2028,11 @@ 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 - let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[0], None, &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[0], None, None, &Vec::new(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 3); assert_eq!(route.paths[0][0].pubkey, nodes[1]); @@ -1011,18 +2057,8 @@ mod tests { assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(3)); // 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(); + let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)]; + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, 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]); @@ -1045,13 +2081,14 @@ mod tests { base_msat: 0, proportional_millionths: 0, }; - vec!(RouteHint { + vec![RouteHint(vec![RouteHintHop { src_node_id: nodes[3].clone(), short_channel_id: 8, fees: zero_fees, cltv_expiry_delta: (8 << 8) | 1, - htlc_minimum_msat: 0, - }, RouteHint { + htlc_minimum_msat: None, + htlc_maximum_msat: None, + }]), RouteHint(vec![RouteHintHop { src_node_id: nodes[4].clone(), short_channel_id: 9, fees: RoutingFees { @@ -1059,23 +2096,47 @@ mod tests { proportional_millionths: 0, }, cltv_expiry_delta: (9 << 8) | 1, - htlc_minimum_msat: 0, - }, RouteHint { + htlc_minimum_msat: None, + htlc_maximum_msat: None, + }]), RouteHint(vec![RouteHintHop { src_node_id: nodes[5].clone(), short_channel_id: 10, fees: zero_fees, cltv_expiry_delta: (10 << 8) | 1, - htlc_minimum_msat: 0, - }) + htlc_minimum_msat: None, + htlc_maximum_msat: None, + }])] } #[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 - 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(); + + // First check that last hop can't have its source as the payee. + let invalid_last_hop = RouteHint(vec![RouteHintHop { + 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, 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, None, &last_hops(&nodes).iter().collect::>(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 5); assert_eq!(route.paths[0][0].pubkey, nodes[1]); @@ -1118,23 +2179,13 @@ 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 - let our_chans = vec![channelmanager::ChannelDetails { - channel_id: [0; 32], - short_channel_id: Some(42), - remote_network_id: nodes[3].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 our_chans = vec![get_channel_details(Some(42), nodes[3].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)]; let mut last_hops = last_hops(&nodes); - let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], Some(&our_chans.iter().collect::>()), &last_hops.iter().collect::>(), 100, 42, Arc::clone(&logger)).unwrap(); + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, Some(&our_chans.iter().collect::>()), &last_hops.iter().collect::>(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 2); assert_eq!(route.paths[0][0].pubkey, nodes[3]); @@ -1151,10 +2202,10 @@ mod tests { assert_eq!(route.paths[0][1].node_features.le_flags(), &Vec::::new()); // We dont pass flags in from invoices yet assert_eq!(route.paths[0][1].channel_features.le_flags(), &Vec::::new()); // We can't learn any flags from invoices, sadly - last_hops[0].fees.base_msat = 1000; + last_hops[0].0[0].fees.base_msat = 1000; // Revert to via 6 as the fee on 8 goes up - let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, &last_hops.iter().collect::>(), 100, 42, Arc::clone(&logger)).unwrap(); + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, None, &last_hops.iter().collect::>(), 100, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 4); assert_eq!(route.paths[0][0].pubkey, nodes[1]); @@ -1188,7 +2239,7 @@ mod tests { assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::::new()); // We can't learn any flags from invoices, sadly // ...but still use 8 for larger payments as 6 has a variable feerate - let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, &last_hops.iter().collect::>(), 2000, 42, Arc::clone(&logger)).unwrap(); + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, None, &last_hops.iter().collect::>(), 2000, 42, Arc::clone(&logger)).unwrap(); assert_eq!(route.paths[0].len(), 5); assert_eq!(route.paths[0][0].pubkey, nodes[1]); @@ -1229,73 +2280,1681 @@ mod tests { assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::::new()); // We can't learn any flags from invoices, sadly } - #[test] - fn unannounced_path_test() { - // We should be able to send a payment to a destination without any help of a routing graph - // if we have a channel with a common counterparty that appears in the first and last hop - // hints. + fn do_unannounced_path_test(last_hop_htlc_max: Option, last_hop_fee_prop: u32, outbound_capacity_msat: u64, route_val: u64) -> Result { let source_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 41).repeat(32)).unwrap()[..]).unwrap()); let middle_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 42).repeat(32)).unwrap()[..]).unwrap()); let target_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 43).repeat(32)).unwrap()[..]).unwrap()); // If we specify a channel to a middle hop, that overrides our local channel view and that gets used - let last_hops = vec![RouteHint { + let last_hops = RouteHint(vec![RouteHintHop { src_node_id: middle_node_id, short_channel_id: 8, fees: RoutingFees { base_msat: 1000, - proportional_millionths: 0, + proportional_millionths: last_hop_fee_prop, }, cltv_expiry_delta: (8 << 8) | 1, - htlc_minimum_msat: 0, - }]; - let our_chans = vec![channelmanager::ChannelDetails { - channel_id: [0; 32], - short_channel_id: Some(42), - remote_network_id: middle_node_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, - }]; - let route = get_route(&source_node_id, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()), &target_node_id, Some(&our_chans.iter().collect::>()), &last_hops.iter().collect::>(), 100, 42, Arc::new(test_utils::TestLogger::new())).unwrap(); + htlc_minimum_msat: None, + htlc_maximum_msat: last_hop_htlc_max, + }]); + let our_chans = vec![get_channel_details(Some(42), middle_node_id, InitFeatures::from_le_bytes(vec![0b11]), outbound_capacity_msat)]; + get_route(&source_node_id, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()), &target_node_id, None, Some(&our_chans.iter().collect::>()), &vec![&last_hops], route_val, 42, Arc::new(test_utils::TestLogger::new())) + } + + #[test] + fn unannounced_path_test() { + // We should be able to send a payment to a destination without any help of a routing graph + // if we have a channel with a common counterparty that appears in the first and last hop + // hints. + let route = do_unannounced_path_test(None, 1, 2000000, 1000000).unwrap(); + let middle_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 42).repeat(32)).unwrap()[..]).unwrap()); + let target_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 43).repeat(32)).unwrap()[..]).unwrap()); assert_eq!(route.paths[0].len(), 2); assert_eq!(route.paths[0][0].pubkey, middle_node_id); assert_eq!(route.paths[0][0].short_channel_id, 42); - assert_eq!(route.paths[0][0].fee_msat, 1000); + assert_eq!(route.paths[0][0].fee_msat, 1001); assert_eq!(route.paths[0][0].cltv_expiry_delta, (8 << 8) | 1); assert_eq!(route.paths[0][0].node_features.le_flags(), &[0b11]); assert_eq!(route.paths[0][0].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly assert_eq!(route.paths[0][1].pubkey, target_node_id); assert_eq!(route.paths[0][1].short_channel_id, 8); - assert_eq!(route.paths[0][1].fee_msat, 100); + assert_eq!(route.paths[0][1].fee_msat, 1000000); assert_eq!(route.paths[0][1].cltv_expiry_delta, 42); 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 } -} - -#[cfg(all(test, feature = "unstable"))] -mod benches { - use super::*; - use util::logger::{Logger, Record}; - use std::fs::File; - use test::Bencher; + #[test] + fn overflow_unannounced_path_test_liquidity_underflow() { + // Previously, when we had a last-hop hint connected directly to a first-hop channel, where + // the last-hop had a fee which overflowed a u64, we'd panic. + // This was due to us adding the first-hop from us unconditionally, causing us to think + // we'd built a path (as our node is in the "best candidate" set), when we had not. + // In this test, we previously hit a subtraction underflow due to having less available + // liquidity at the last hop than 0. + assert!(do_unannounced_path_test(Some(21_000_000_0000_0000_000), 0, 21_000_000_0000_0000_000, 21_000_000_0000_0000_000).is_err()); + } - struct DummyLogger {} - impl Logger for DummyLogger { - fn log(&self, _record: &Record) {} + #[test] + fn overflow_unannounced_path_test_feerate_overflow() { + // This tests for the same case as above, except instead of hitting a subtraction + // underflow, we hit a case where the fee charged at a hop overflowed. + assert!(do_unannounced_path_test(Some(21_000_000_0000_0000_000), 50000, 21_000_000_0000_0000_000, 21_000_000_0000_0000_000).is_err()); } - #[bench] - fn generate_routes(bench: &mut Bencher) { - let mut d = File::open("net_graph-2021-02-12.bin").expect("Please fetch https://bitcoin.ninja/ldk-net_graph-879e309c128-2020-02-12.bin and place it at lightning/net_graph-2021-02-12.bin"); + #[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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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); + } + + // Check that setting outbound_capacity_msat in first_hops limits the channels. + // Disable channel #1 and use another 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: 1, + timestamp: 3, + flags: 2, + 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() + }); + + // Now, limit the first_hop by the outbound_capacity_msat of 200_000 sats. + let our_chans = vec![get_channel_details(Some(42), nodes[0].clone(), InitFeatures::from_le_bytes(vec![0b11]), 200_000_000)]; + + { + // 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], + Some(InvoiceFeatures::known()), Some(&our_chans.iter().collect::>()), &Vec::new(), 200_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], + Some(InvoiceFeatures::known()), Some(&our_chans.iter().collect::>()), &Vec::new(), 200_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, 200_000_000); + } + + // Enable channel #1 back. + 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: 4, + 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() + }); + + + // 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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, 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], Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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], + Some(InvoiceFeatures::known()), 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); + } + } + + #[test] + fn min_criteria_consistency() { + // Test that we don't use an inconsistent metric between updating and walking nodes during + // our Dijkstra's pass. In the initial version of MPP, the "best source" for a given node + // was updated with a different criterion from the heap sorting, resulting in loops in + // calculated paths. We test for that specific case here. + + // We construct a network that looks like this: + // + // node2 -1(3)2- node3 + // 2 2 + // (2) (4) + // 1 1 + // node1 -1(5)2- node4 -1(1)2- node6 + // 2 + // (6) + // 1 + // our_node + // + // We create a loop on the side of our real path - our destination is node 6, with a + // previous hop of node 4. From 4, the cheapest previous path is channel 2 from node 2, + // followed by node 3 over channel 3. Thereafter, the cheapest next-hop is back to node 4 + // (this time over channel 4). Channel 4 has 0 htlc_minimum_msat whereas channel 1 (the + // other channel with a previous-hop of node 4) has a high (but irrelevant to the overall + // payment) htlc_minimum_msat. In the original algorithm, this resulted in node4's + // "previous hop" being set to node 3, creating a loop in the path. + let secp_ctx = Secp256k1::new(); + let logger = Arc::new(test_utils::TestLogger::new()); + let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), None, Arc::clone(&logger)); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6); + update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 6, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (6 << 8) | 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 5, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (5 << 8) | 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 100, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 4, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (4 << 8) | 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 3, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (3 << 8) | 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 2, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (2 << 8) | 0, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[6], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1); + update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 1, + timestamp: 1, + flags: 0, + cltv_expiry_delta: (1 << 8) | 0, + htlc_minimum_msat: 100, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[6], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0); + + { + // Now ensure the route flows simply over nodes 1 and 4 to 6. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[6], None, None, &Vec::new(), 10_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + assert_eq!(route.paths[0].len(), 3); + + assert_eq!(route.paths[0][0].pubkey, nodes[1]); + assert_eq!(route.paths[0][0].short_channel_id, 6); + assert_eq!(route.paths[0][0].fee_msat, 100); + assert_eq!(route.paths[0][0].cltv_expiry_delta, (5 << 8) | 0); + assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(1)); + assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(6)); + + assert_eq!(route.paths[0][1].pubkey, nodes[4]); + assert_eq!(route.paths[0][1].short_channel_id, 5); + assert_eq!(route.paths[0][1].fee_msat, 0); + assert_eq!(route.paths[0][1].cltv_expiry_delta, (1 << 8) | 0); + assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(4)); + assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(5)); + + assert_eq!(route.paths[0][2].pubkey, nodes[6]); + assert_eq!(route.paths[0][2].short_channel_id, 1); + assert_eq!(route.paths[0][2].fee_msat, 10_000); + assert_eq!(route.paths[0][2].cltv_expiry_delta, 42); + assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(6)); + assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(1)); + } + } + + + #[test] + fn exact_fee_liquidity_limit() { + // Test that if, while walking the graph, we find a hop that has exactly enough liquidity + // for us, including later hop fees, we take it. In the first version of our MPP algorithm + // we calculated fees on a higher value, resulting in us ignoring such paths. + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, _, nodes) = get_nodes(&secp_ctx); + + // We modify the graph to set the htlc_maximum of channel 2 to below the value we wish to + // send. + 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(85_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: 0, + cltv_expiry_delta: (4 << 8) | 1, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(270_000), + fee_base_msat: 0, + fee_proportional_millionths: 1000000, + excess_data: Vec::new() + }); + + { + // Now, attempt to route 90 sats, which is exactly 90 sats at the last hop, plus the + // 200% fee charged channel 13 in the 1-to-2 direction. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], None, None, &Vec::new(), 90_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + 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, 12); + assert_eq!(route.paths[0][0].fee_msat, 90_000*2); + assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1); + assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(8)); + assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(12)); + + 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, 90_000); + 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 htlc_max_reduction_below_min() { + // Test that if, while walking the graph, we reduce the value being sent to meet an + // htlc_maximum_msat, we don't end up undershooting a later htlc_minimum_msat. In the + // initial version of MPP we'd accept such routes but reject them while recalculating fees, + // resulting in us thinking there is no possible path, even if other paths exist. + let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph(); + let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + // We modify the graph to set the htlc_minimum of channel 2 and 4 as needed - channel 2 + // gets an htlc_maximum_msat of 80_000 and channel 4 an htlc_minimum_msat of 90_000. We + // then try to send 90_000. + 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(80_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: (4 << 8) | 1, + htlc_minimum_msat: 90_000, + htlc_maximum_msat: OptionalField::Absent, + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + { + // Now, attempt to route 90 sats, hitting the htlc_minimum on channel 4, but + // overshooting the htlc_maximum on channel 2. Thus, we should pick the (absurdly + // expensive) channels 12-13 path. + let route = get_route(&our_id, &net_graph_msg_handler.network_graph.read().unwrap(), &nodes[2], Some(InvoiceFeatures::known()), None, &Vec::new(), 90_000, 42, Arc::clone(&logger)).unwrap(); + assert_eq!(route.paths.len(), 1); + 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, 12); + assert_eq!(route.paths[0][0].fee_msat, 90_000*2); + assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1); + assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(8)); + assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(12)); + + 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, 90_000); + assert_eq!(route.paths[0][1].cltv_expiry_delta, 42); + assert_eq!(route.paths[0][1].node_features.le_flags(), InvoiceFeatures::known().le_flags()); + assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13)); + } + } + + #[cfg(not(feature = "no_std"))] + pub(super) fn random_init_seed() -> u64 { + // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG. + use core::hash::{BuildHasher, Hasher}; + let seed = std::collections::hash_map::RandomState::new().build_hasher().finish(); + println!("Using seed of {}", seed); + seed + } + #[cfg(not(feature = "no_std"))] + use util::ser::Readable; + + #[test] + #[cfg(not(feature = "no_std"))] + fn generate_routes() { + let mut d = match super::test_utils::get_route_file() { + Ok(f) => f, + Err(e) => { + eprintln!("{}", e); + return; + }, + }; + let graph = NetworkGraph::read(&mut d).unwrap(); + + // First, get 100 (source, destination) pairs for which route-getting actually succeeds... + let mut seed = random_init_seed() as usize; + 'load_endpoints: for _ in 0..10 { + loop { + seed = seed.overflowing_mul(0xdeadbeef).0; + let src = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); + seed = seed.overflowing_mul(0xdeadbeef).0; + let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); + let amt = seed as u64 % 200_000_000; + if get_route(src, &graph, dst, None, None, &[], amt, 42, &test_utils::TestLogger::new()).is_ok() { + continue 'load_endpoints; + } + } + } + } + + #[test] + #[cfg(not(feature = "no_std"))] + fn generate_routes_mpp() { + let mut d = match super::test_utils::get_route_file() { + Ok(f) => f, + Err(e) => { + eprintln!("{}", e); + return; + }, + }; + let graph = NetworkGraph::read(&mut d).unwrap(); + + // First, get 100 (source, destination) pairs for which route-getting actually succeeds... + let mut seed = random_init_seed() as usize; + 'load_endpoints: for _ in 0..10 { + loop { + seed = seed.overflowing_mul(0xdeadbeef).0; + let src = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); + seed = seed.overflowing_mul(0xdeadbeef).0; + let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); + let amt = seed as u64 % 200_000_000; + if get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &test_utils::TestLogger::new()).is_ok() { + continue 'load_endpoints; + } + } + } + } +} + +#[cfg(all(test, not(feature = "no_std")))] +pub(crate) mod test_utils { + use std::fs::File; + /// Tries to open a network graph file, or panics with a URL to fetch it. + pub(crate) fn get_route_file() -> Result { + let res = File::open("net_graph-2021-05-31.bin") // By default we're run in RL/lightning + .or_else(|_| File::open("lightning/net_graph-2021-05-31.bin")) // We may be run manually in RL/ + .or_else(|_| { // Fall back to guessing based on the binary location + // path is likely something like .../rust-lightning/target/debug/deps/lightning-... + let mut path = std::env::current_exe().unwrap(); + path.pop(); // lightning-... + path.pop(); // deps + path.pop(); // debug + path.pop(); // target + path.push("lightning"); + path.push("net_graph-2021-05-31.bin"); + eprintln!("{}", path.to_str().unwrap()); + File::open(path) + }) + .map_err(|_| "Please fetch https://bitcoin.ninja/ldk-net_graph-v0.0.15-2021-05-31.bin and place it at lightning/net_graph-2021-05-31.bin"); + #[cfg(require_route_graph_test)] + return Ok(res.unwrap()); + #[cfg(not(require_route_graph_test))] + return res; + } +} + +#[cfg(all(test, feature = "unstable", not(feature = "no_std")))] +mod benches { + use super::*; + use util::logger::{Logger, Record}; + + use test::Bencher; + + struct DummyLogger {} + impl Logger for DummyLogger { + fn log(&self, _record: &Record) {} + } + + #[bench] + fn generate_routes(bench: &mut Bencher) { + let mut d = test_utils::get_route_file().unwrap(); + let graph = NetworkGraph::read(&mut d).unwrap(); + + // First, get 100 (source, destination) pairs for which route-getting actually succeeds... + let mut path_endpoints = Vec::new(); + let mut seed: usize = 0xdeadbeef; + 'load_endpoints: for _ in 0..100 { + loop { + seed *= 0xdeadbeef; + let src = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); + seed *= 0xdeadbeef; + let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); + let amt = seed as u64 % 1_000_000; + if get_route(src, &graph, dst, None, None, &[], amt, 42, &DummyLogger{}).is_ok() { + path_endpoints.push((src, dst, amt)); + continue 'load_endpoints; + } + } + } + + // ...then benchmark finding paths between the nodes we learned. + let mut idx = 0; + bench.iter(|| { + let (src, dst, amt) = path_endpoints[idx % path_endpoints.len()]; + assert!(get_route(src, &graph, dst, None, None, &[], amt, 42, &DummyLogger{}).is_ok()); + idx += 1; + }); + } + + #[bench] + fn generate_mpp_routes(bench: &mut Bencher) { + let mut d = test_utils::get_route_file().unwrap(); let graph = NetworkGraph::read(&mut d).unwrap(); // First, get 100 (source, destination) pairs for which route-getting actually succeeds... @@ -1308,7 +3967,7 @@ mod benches { seed *= 0xdeadbeef; let dst = graph.get_nodes().keys().skip(seed % graph.get_nodes().len()).next().unwrap(); let amt = seed as u64 % 1_000_000; - if get_route(src, &graph, dst, None, &[], amt, 42, &DummyLogger{}).is_ok() { + if get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &DummyLogger{}).is_ok() { path_endpoints.push((src, dst, amt)); continue 'load_endpoints; } @@ -1319,7 +3978,7 @@ mod benches { let mut idx = 0; bench.iter(|| { let (src, dst, amt) = path_endpoints[idx % path_endpoints.len()]; - assert!(get_route(src, &graph, dst, None, &[], amt, 42, &DummyLogger{}).is_ok()); + assert!(get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &DummyLogger{}).is_ok()); idx += 1; }); }