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Track lowest inbound channel fees per channel direction #1722

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f98cc06
Track lowest inbound channel fees per channel direction
naumenkogs Sep 15, 2022
093cf1d
f simplify serialization stuff
naumenkogs Sep 16, 2022
ae53d1c
Better track lowest_inbound_channel_fees
naumenkogs Sep 16, 2022
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135 changes: 94 additions & 41 deletions lightning/src/routing/gossip.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -707,37 +707,45 @@ pub struct ChannelInfo {
/// (which we can probably assume we are - no-std environments probably won't have a full
/// network graph in memory!).
announcement_received_time: u64,
/// Lowest fees to enter the first direction, based on the cheapest channel to the source node.
/// The two fields (flat and proportional fee) are independent,
/// meaning they don't have to refer to the same channel.
pub lowest_inbound_channel_fees_to_one: Option<RoutingFees>,
/// Lowest fees to enter the second direction, based on the cheapest channel to the source node.
/// The two fields (flat and proportional fee) are independent,
/// meaning they don't have to refer to the same channel.
pub lowest_inbound_channel_fees_to_two: Option<RoutingFees>,
}

impl ChannelInfo {
/// Returns a [`DirectedChannelInfo`] for the channel directed to the given `target` from a
/// returned `source`, or `None` if `target` is not one of the channel's counterparties.
pub fn as_directed_to(&self, target: &NodeId) -> Option<(DirectedChannelInfo, &NodeId)> {
let (direction, source) = {
let (direction, source, lowest_inbound_channel_fees) = {
if target == &self.node_one {
(self.two_to_one.as_ref(), &self.node_two)
(self.two_to_one.as_ref(), &self.node_two, self.lowest_inbound_channel_fees_to_two)
} else if target == &self.node_two {
(self.one_to_two.as_ref(), &self.node_one)
(self.one_to_two.as_ref(), &self.node_one, self.lowest_inbound_channel_fees_to_one)
} else {
return None;
}
};
Some((DirectedChannelInfo::new(self, direction), source))
Some((DirectedChannelInfo::new(self, direction, lowest_inbound_channel_fees), source))
}

/// Returns a [`DirectedChannelInfo`] for the channel directed from the given `source` to a
/// returned `target`, or `None` if `source` is not one of the channel's counterparties.
pub fn as_directed_from(&self, source: &NodeId) -> Option<(DirectedChannelInfo, &NodeId)> {
let (direction, target) = {
let (direction, target, lowest_inbound_channel_fees) = {
if source == &self.node_one {
(self.one_to_two.as_ref(), &self.node_two)
(self.one_to_two.as_ref(), &self.node_two, self.lowest_inbound_channel_fees_to_two)
} else if source == &self.node_two {
(self.two_to_one.as_ref(), &self.node_one)
(self.two_to_one.as_ref(), &self.node_one, self.lowest_inbound_channel_fees_to_one)
} else {
return None;
}
};
Some((DirectedChannelInfo::new(self, direction), target))
Some((DirectedChannelInfo::new(self, direction, lowest_inbound_channel_fees), target))
}

/// Returns a [`ChannelUpdateInfo`] based on the direction implied by the channel_flag.
Expand Down Expand Up @@ -770,6 +778,8 @@ impl Writeable for ChannelInfo {
(8, self.two_to_one, required),
(10, self.capacity_sats, required),
(12, self.announcement_message, required),
(14, self.lowest_inbound_channel_fees_to_one, option),
(16, self.lowest_inbound_channel_fees_to_two, option),
});
Ok(())
}
Expand Down Expand Up @@ -803,6 +813,8 @@ impl Readable for ChannelInfo {
let mut two_to_one_wrap: Option<ChannelUpdateInfoDeserWrapper> = None;
init_tlv_field_var!(capacity_sats, required);
init_tlv_field_var!(announcement_message, required);
let mut lowest_inbound_channel_fees_to_one = None;
let mut lowest_inbound_channel_fees_to_two = None;
read_tlv_fields!(reader, {
(0, features, required),
(1, announcement_received_time, (default_value, 0)),
Expand All @@ -812,6 +824,8 @@ impl Readable for ChannelInfo {
(8, two_to_one_wrap, ignorable),
(10, capacity_sats, required),
(12, announcement_message, required),
(14, lowest_inbound_channel_fees_to_one, option),
(16, lowest_inbound_channel_fees_to_two, option),
});

Ok(ChannelInfo {
Expand All @@ -823,6 +837,8 @@ impl Readable for ChannelInfo {
capacity_sats: init_tlv_based_struct_field!(capacity_sats, required),
announcement_message: init_tlv_based_struct_field!(announcement_message, required),
announcement_received_time: init_tlv_based_struct_field!(announcement_received_time, (default_value, 0)),
lowest_inbound_channel_fees_to_one: init_tlv_based_struct_field!(lowest_inbound_channel_fees_to_one, option),
lowest_inbound_channel_fees_to_two: init_tlv_based_struct_field!(lowest_inbound_channel_fees_to_two, option),
})
}
}
Expand All @@ -835,11 +851,12 @@ pub struct DirectedChannelInfo<'a> {
direction: Option<&'a ChannelUpdateInfo>,
htlc_maximum_msat: u64,
effective_capacity: EffectiveCapacity,
lowest_inbound_channel_fees: Option<RoutingFees>,
}

impl<'a> DirectedChannelInfo<'a> {
#[inline]
fn new(channel: &'a ChannelInfo, direction: Option<&'a ChannelUpdateInfo>) -> Self {
fn new(channel: &'a ChannelInfo, direction: Option<&'a ChannelUpdateInfo>, lowest_inbound_channel_fees: Option<RoutingFees>) -> Self {
let htlc_maximum_msat = direction.map(|direction| direction.htlc_maximum_msat);
let capacity_msat = channel.capacity_sats.map(|capacity_sats| capacity_sats * 1000);

Expand All @@ -858,7 +875,7 @@ impl<'a> DirectedChannelInfo<'a> {
};

Self {
channel, direction, htlc_maximum_msat, effective_capacity
channel, direction, htlc_maximum_msat, effective_capacity, lowest_inbound_channel_fees,
}
}

Expand All @@ -882,6 +899,13 @@ impl<'a> DirectedChannelInfo<'a> {
self.effective_capacity
}

/// Returns the [`Option<RoutingFees>`] to reach the channel in the direction.
///
/// This is based on the known and enabled channels to the entry node.
pub fn lowest_inbound_channel_fees(&self) -> Option<RoutingFees> {
self.lowest_inbound_channel_fees
}

/// Returns `Some` if [`ChannelUpdateInfo`] is available in the direction.
pub(super) fn with_update(self) -> Option<DirectedChannelInfoWithUpdate<'a>> {
match self.direction {
Expand Down Expand Up @@ -917,6 +941,10 @@ impl<'a> DirectedChannelInfoWithUpdate<'a> {
/// Returns the [`EffectiveCapacity`] of the channel in the direction.
#[inline]
pub(super) fn effective_capacity(&self) -> EffectiveCapacity { self.inner.effective_capacity() }

#[inline]
pub(super) fn lowest_inbound_channel_fees(&self) -> Option<RoutingFees> { self.inner.lowest_inbound_channel_fees() }

}

impl<'a> fmt::Debug for DirectedChannelInfoWithUpdate<'a> {
Expand Down Expand Up @@ -1382,6 +1410,8 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
capacity_sats: None,
announcement_message: None,
announcement_received_time: timestamp,
lowest_inbound_channel_fees_to_one: None,
lowest_inbound_channel_fees_to_two: None,
};

self.add_channel_between_nodes(short_channel_id, channel_info, None)
Expand All @@ -1408,7 +1438,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
// b) we don't track UTXOs of channels we know about and remove them if they
// get reorg'd out.
// c) it's unclear how to do so without exposing ourselves to massive DoS risk.
Self::remove_channel_in_nodes(&mut nodes, &entry.get(), short_channel_id);
self.remove_channel_in_nodes(&mut nodes, &entry.get(), short_channel_id);
*entry.get_mut() = channel_info;
} else {
return Err(LightningError{err: "Already have knowledge of channel".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
Expand Down Expand Up @@ -1524,6 +1554,8 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
announcement_message: if msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY
{ full_msg.cloned() } else { None },
announcement_received_time,
lowest_inbound_channel_fees_to_one: None,
lowest_inbound_channel_fees_to_two: None,
};

self.add_channel_between_nodes(msg.short_channel_id, chan_info, utxo_value)
Expand All @@ -1538,7 +1570,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
if is_permanent {
if let Some(chan) = channels.remove(&short_channel_id) {
let mut nodes = self.nodes.write().unwrap();
Self::remove_channel_in_nodes(&mut nodes, &chan, short_channel_id);
self.remove_channel_in_nodes(&mut nodes, &chan, short_channel_id);
}
} else {
if let Some(chan) = channels.get_mut(&short_channel_id) {
Expand Down Expand Up @@ -1619,7 +1651,7 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
let mut nodes = self.nodes.write().unwrap();
for scid in scids_to_remove {
let info = channels.remove(&scid).expect("We just accessed this scid, it should be present");
Self::remove_channel_in_nodes(&mut nodes, &info, scid);
self.remove_channel_in_nodes(&mut nodes, &info, scid);
}
}
}
Expand Down Expand Up @@ -1752,47 +1784,25 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
}

let mut nodes = self.nodes.write().unwrap();
let node = nodes.get_mut(&dest_node_id).unwrap();
if chan_enabled {
let node = nodes.get_mut(&dest_node_id).unwrap();
let mut base_msat = msg.fee_base_msat;
let mut proportional_millionths = msg.fee_proportional_millionths;
if let Some(fees) = node.lowest_inbound_channel_fees {
base_msat = cmp::min(base_msat, fees.base_msat);
proportional_millionths = cmp::min(proportional_millionths, fees.proportional_millionths);
}
node.lowest_inbound_channel_fees = Some(RoutingFees {
base_msat,
proportional_millionths
});
self.update_lowest_inbound_channel_fees(dest_node_id, node, &mut channels, Some(RoutingFees {
base_msat, proportional_millionths
}));
} else if chan_was_enabled {
let node = nodes.get_mut(&dest_node_id).unwrap();
let mut lowest_inbound_channel_fees = None;

for chan_id in node.channels.iter() {
let chan = channels.get(chan_id).unwrap();
let chan_info_opt;
if chan.node_one == dest_node_id {
chan_info_opt = chan.two_to_one.as_ref();
} else {
chan_info_opt = chan.one_to_two.as_ref();
}
if let Some(chan_info) = chan_info_opt {
if chan_info.enabled {
let fees = lowest_inbound_channel_fees.get_or_insert(RoutingFees {
base_msat: u32::max_value(), proportional_millionths: u32::max_value() });
fees.base_msat = cmp::min(fees.base_msat, chan_info.fees.base_msat);
fees.proportional_millionths = cmp::min(fees.proportional_millionths, chan_info.fees.proportional_millionths);
}
}
}

node.lowest_inbound_channel_fees = lowest_inbound_channel_fees;
self.recompute_and_update_lowest_inbound_channel_fees(dest_node_id, node, &mut channels);
}

Ok(())
}

fn remove_channel_in_nodes(nodes: &mut BTreeMap<NodeId, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
fn remove_channel_in_nodes(&self, nodes: &mut BTreeMap<NodeId, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
macro_rules! remove_from_node {
($node_id: expr) => {
if let BtreeEntry::Occupied(mut entry) = nodes.entry($node_id) {
Expand All @@ -1805,12 +1815,51 @@ impl<L: Deref> NetworkGraph<L> where L::Target: Logger {
} else {
panic!("Had channel that pointed to unknown node (ie inconsistent network map)!");
}
if let Some(node) = nodes.get_mut(&$node_id) {
self.recompute_and_update_lowest_inbound_channel_fees($node_id, node, &mut self.channels.write().unwrap());
}
}
}

remove_from_node!(chan.node_one);
remove_from_node!(chan.node_two);
}

fn recompute_and_update_lowest_inbound_channel_fees(&self, node_id: NodeId, node: &mut NodeInfo, channels: &mut BTreeMap<u64, ChannelInfo>) {
let mut updated_lowest_inbound_channel_fee = None;
for chan_id in node.channels.iter() {
let chan = channels.get(chan_id).unwrap();
let chan_info_opt;
if chan.node_one == node_id {
chan_info_opt = chan.two_to_one.as_ref();
} else {
chan_info_opt = chan.one_to_two.as_ref();
}
if let Some(chan_info) = chan_info_opt {
if chan_info.enabled {
let fees = updated_lowest_inbound_channel_fee.get_or_insert(RoutingFees {
base_msat: u32::max_value(), proportional_millionths: u32::max_value() });
fees.base_msat = cmp::min(fees.base_msat, chan_info.fees.base_msat);
fees.proportional_millionths = cmp::min(fees.proportional_millionths, chan_info.fees.proportional_millionths);
}
}
}
self.update_lowest_inbound_channel_fees(node_id, node, channels, updated_lowest_inbound_channel_fee);
}

fn update_lowest_inbound_channel_fees(&self, node_id: NodeId, node: &mut NodeInfo, channels: &mut BTreeMap<u64, ChannelInfo>, updated_fees: Option<RoutingFees>) {
node.lowest_inbound_channel_fees = updated_fees;
for (_, chan) in channels.iter_mut() {
if chan.node_one == node_id {
chan.lowest_inbound_channel_fees_to_two = updated_fees;
}

if chan.node_two == node_id {
chan.lowest_inbound_channel_fees_to_one = updated_fees;
}
}
}

}

impl ReadOnlyNetworkGraph<'_> {
Expand Down Expand Up @@ -3019,6 +3068,8 @@ mod tests {
capacity_sats: None,
announcement_message: None,
announcement_received_time: 87654,
lowest_inbound_channel_fees_to_one: None,
lowest_inbound_channel_fees_to_two: None,
};

let mut encoded_chan_info: Vec<u8> = Vec::new();
Expand All @@ -3037,6 +3088,8 @@ mod tests {
capacity_sats: None,
announcement_message: None,
announcement_received_time: 87654,
lowest_inbound_channel_fees_to_one: None,
lowest_inbound_channel_fees_to_two: None,
};

let mut encoded_chan_info: Vec<u8> = Vec::new();
Expand Down
12 changes: 11 additions & 1 deletion lightning/src/routing/router.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -483,6 +483,16 @@ impl<'a> CandidateRouteHop<'a> {
CandidateRouteHop::PrivateHop { .. } => EffectiveCapacity::Infinite,
}
}

fn lowest_inbound_channel_fees(&self) -> Option<RoutingFees> {
match self {
CandidateRouteHop::FirstHop { .. } => Some(RoutingFees {
base_msat: 0, proportional_millionths: 0,
}),
CandidateRouteHop::PublicHop { info, .. } => info.lowest_inbound_channel_fees(),
CandidateRouteHop::PrivateHop { .. } => None,
}
}
}

#[inline]
Expand Down Expand Up @@ -1070,7 +1080,7 @@ where L::Target: Logger {
// as a way to reach the $dest_node_id.
let mut fee_base_msat = 0;
let mut fee_proportional_millionths = 0;
if let Some(Some(fees)) = network_nodes.get(&$src_node_id).map(|node| node.lowest_inbound_channel_fees) {
if let Some(fees) = $candidate.lowest_inbound_channel_fees() {
fee_base_msat = fees.base_msat;
fee_proportional_millionths = fees.proportional_millionths;
}
Expand Down