use std::collections::btree_map::Entry as BtreeEntry;
use std;
-/// Receives network updates from peers to track view of the network.
+/// Receives and validates network updates from peers,
+/// stores authentic and relevant data as a network graph.
+/// This network graph is then used for routing payments.
+/// Provides interface to help with initial routing sync by
+/// serving historical announcements.
pub struct NetGraphMsgHandler {
secp_ctx: Secp256k1<secp256k1::VerifyOnly>,
/// Representation of the payment channel network
impl NetGraphMsgHandler {
/// Creates a new tracker of the actual state of the network of channels and nodes,
- /// assuming fresh Network Graph
+ /// assuming a fresh network graph.
+ /// Chain monitor is used to make sure announced channels exist on-chain,
+ /// channel data is correct, and that the announcement is signed with
+ /// channel owners' keys.
pub fn new(chain_monitor: Arc<ChainWatchInterface>, logger: Arc<Logger>) -> Self {
NetGraphMsgHandler {
secp_ctx: Secp256k1::verification_only(),
}
}
- /// Get network addresses by node id
+ /// Get network addresses by node id.
+ /// Returns None if the requested node is completely unknown,
+ /// or if node announcement for the node was never received.
pub fn get_addresses(&self, pubkey: &PublicKey) -> Option<Vec<NetAddress>> {
let network = self.network_graph.read().unwrap();
if let Some(node) = network.get_nodes().get(pubkey) {
}
#[derive(PartialEq, Debug)]
-/// Details regarding one direction of a channel
+/// Details about one direction of a channel. Received
+/// within a channel update.
pub struct DirectionalChannelInfo {
- /// When the last update to the channel direction was issued
+ /// When the last update to the channel direction was issued.
+ /// Value is opaque, as set in the announcement.
pub last_update: u32,
- /// Whether the channel can be currently used for payments
+ /// Whether the channel can be currently used for payments (in this one direction).
pub enabled: bool,
- /// The difference in CLTV values between the source and the destination node of the channel
+ /// The difference in CLTV values that you must have when routing through this channel.
pub cltv_expiry_delta: u16,
/// The minimum value, which must be relayed to the next hop via the channel
pub htlc_minimum_msat: u64,
});
#[derive(PartialEq)]
-/// Details regarding a channel (both directions)
+/// Details about a channel (both directions).
+/// Received within a channel announcement.
pub struct ChannelInfo {
/// Protocol features of a channel communicated during its announcement
pub features: ChannelFeatures,
/// Details about the second direction of a channel
pub two_to_one: Option<DirectionalChannelInfo>,
/// An initial announcement of the channel
- //this is cached here so we can send out it later if required by initial routing sync
- //keep an eye on this to see if the extra memory is a problem
+ /// Mostly redundant with the data we store in fields explicitly.
+ /// Everything else is useful only for sending out for initial routing sync.
+ /// Not stored if contains excess data to prevent DoS.
pub announcement_message: Option<msgs::ChannelAnnouncement>,
}
/// Fees for routing via a given channel or a node
#[derive(Eq, PartialEq, Copy, Clone, Debug)]
pub struct RoutingFees {
- /// Flat routing fee
+ /// Flat routing fee in satoshis
pub base_msat: u32,
- /// Liquidity-based routing fee
+ /// Liquidity-based routing fee in millionths of a routed amount.
+ /// In other words, 10000 is 1%.
pub proportional_millionths: u32,
}
pub struct NodeAnnouncementInfo {
/// Protocol features the node announced support for
pub features: NodeFeatures,
- /// When the last known update to the node state was issued
+ /// When the last known update to the node state was issued.
+ /// Value is opaque, as set in the announcement.
pub last_update: u32,
/// Color assigned to the node
pub rgb: [u8; 3],
- /// Moniker assigned to the node
+ /// Moniker assigned to the node.
+ /// May be invalid or malicious (eg control chars),
+ /// should not be exposed to the user.
pub alias: [u8; 32],
/// Internet-level addresses via which one can connect to the node
pub addresses: Vec<NetAddress>,
/// An initial announcement of the node
- // this is cached here so we can send out it later if required by initial routing sync
- // keep an eye on this to see if the extra memory is a problem
+ /// Mostly redundant with the data we store in fields explicitly.
+ /// Everything else is useful only for sending out for initial routing sync.
+ /// Not stored if contains excess data to prevent DoS.
pub announcement_message: Option<msgs::NodeAnnouncement>
}
}
#[derive(PartialEq)]
-/// Details regarding a node in the network
+/// Details about a node in the network, known from the network announcement.
pub struct NodeInfo {
/// All valid channels a node has announced
pub channels: Vec<u64>,
- /// Lowest fees enabling routing via any of the known channels to a node
+ /// Lowest fees enabling routing via any of the known channels to a 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: Option<RoutingFees>,
- /// More information about a node from node_announcement
- /// Optional because we may have a NodeInfo entry before having received the announcement
+ /// More information about a node from node_announcement.
+ /// Optional because we store a Node entry after learning about it from
+ /// a channel announcement, but before receiving a node announcement.
pub announcement_info: Option<NodeAnnouncementInfo>
}
}
impl NetworkGraph {
- /// Returns all known valid channels
+ /// Returns all known valid channels' short ids along with announced channel info.
pub fn get_channels<'a>(&'a self) -> &'a BTreeMap<u64, ChannelInfo> { &self.channels }
- /// Returns all known nodes
+ /// Returns all known nodes' public keys along with announced node info.
pub fn get_nodes<'a>(&'a self) -> &'a BTreeMap<PublicKey, NodeInfo> { &self.nodes }
/// For an already known node (from channel announcements), update its stored properties from a given node announcement
}
}
- /// For a new or already known (from previous announcement) channel, store or update channel info,
- /// after making sure it corresponds to a real transaction on-chain.
+ /// For a new or already known (from previous announcement) channel, store or update channel info.
/// Also store nodes (if not stored yet) the channel is between, and make node aware of this channel.
+ /// Checking utxo on-chain is useful if we receive an update for already known channel id,
+ /// which is probably result of a reorg. In that case, we update channel info only if the
+ /// utxo was checked, otherwise stick to the existing update, to prevent DoS risks.
/// Announcement signatures are checked here only if Secp256k1 object is provided.
fn update_channel_from_announcement(&mut self, msg: &msgs::ChannelAnnouncement, checked_utxo: bool, secp_ctx: Option<&Secp256k1<secp256k1::VerifyOnly>>) -> Result<bool, LightningError> {
if let Some(sig_verifier) = secp_ctx {
}
}
- /// For an already known (from announcement) channel, update info regarding one of the directions of a channel.
+ /// For an already known (from announcement) channel, update info about one of the directions of a channel.
/// Announcement signatures are checked here only if Secp256k1 object is provided.
fn update_channel(&mut self, msg: &msgs::ChannelUpdate, secp_ctx: Option<&Secp256k1<secp256k1::VerifyOnly>>) -> Result<bool, LightningError> {
let dest_node_id;
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