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Merge pull request #1708 from tnull/2022-09-rgs-unpub-modules

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Improve RGS documentation
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Arik 2022-09-15 09:55:39 -07:00 • committed by GitHub
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3
lightning-rapid-gossip-sync/Cargo.toml
View file

@ -10,6 +10,9 @@ Utility to process gossip routing data from Rapid Gossip Sync Server.
"""
[features]
default = ["std"]
no-std = ["lightning/no-std"]
std = ["lightning/std"]
_bench_unstable = []
[dependencies]

80
lightning-rapid-gossip-sync/src/lib.rs
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@ -10,24 +10,35 @@
#![deny(unused_mut)]
#![deny(unused_variables)]
#![deny(unused_imports)]
//! This crate exposes functionality to rapidly sync gossip data, aimed primarily at mobile
//! This crate exposes client functionality to rapidly sync gossip data, aimed primarily at mobile
//! devices.
//!
//! The server sends a compressed response containing differential gossip data. The gossip data is
//! formatted compactly, omitting signatures and opportunistically incremental where previous
//! channel updates are known (a mechanism that is enabled when the timestamp of the last known
//! channel update is communicated). A reference server implementation can be found
//! [here](https://github.com/lightningdevkit/rapid-gossip-sync-server).
//! The rapid gossip sync server will provide a compressed response containing differential gossip
//! data. The gossip data is formatted compactly, omitting signatures and opportunistically
//! incremental where previous channel updates are known. This mechanism is enabled when the
//! timestamp of the last known channel update is communicated. A reference server implementation
//! can be found [on Github](https://github.com/lightningdevkit/rapid-gossip-sync-server).
//!
//! An example server request could look as simple as the following. Note that the first ever rapid
//! sync should use `0` for `last_sync_timestamp`:
//! The primary benefit of this syncing mechanism is that it allows a low-powered client to offload
//! the validation of gossip signatures to a semi-trusted server. This enables the client to
//! privately calculate routes for payments, and to do so much faster than requiring a full
//! peer-to-peer gossip sync to complete.
//!
//! The server calculates its response on the basis of a client-provided `latest_seen` timestamp,
//! i.e., the server will return all rapid gossip sync data it has seen after the given timestamp.
//!
//! # Getting Started
//! Firstly, the data needs to be retrieved from the server. For example, you could use the server
//! at <https://rapidsync.lightningdevkit.org> with the following request format:
//!
//! ```shell
//! curl -o rapid_sync.lngossip https://rapidsync.lightningdevkit.org/snapshot/<last_sync_timestamp>
//! ```
//! Note that the first ever rapid sync should use `0` for `last_sync_timestamp`.
//!
//! Then, call the network processing function. In this example, we process the update by reading
//! its contents from disk, which we do by calling the `sync_network_graph_with_file_path` method:
//! After the gossip data snapshot has been downloaded, one of the client's graph processing
//! functions needs to be called. In this example, we process the update by reading its contents
//! from disk, which we do by calling [sync_network_graph_with_file_path]:
//!
//! ```
//! use bitcoin::blockdata::constants::genesis_block;
@ -47,43 +58,32 @@
//! let rapid_sync = RapidGossipSync::new(&network_graph);
//! let new_last_sync_timestamp_result = rapid_sync.sync_network_graph_with_file_path("./rapid_sync.lngossip");
//! ```
//!
//! The primary benefit this syncing mechanism provides is that given a trusted server, a
//! low-powered client can offload the validation of gossip signatures. This enables a client to
//! privately calculate routes for payments, and do so much faster and earlier than requiring a full
//! peer-to-peer gossip sync to complete.
//!
//! The reason the rapid sync server requires trust is that it could provide bogus data, though at
//! worst, all that would result in is a fake network topology, which wouldn't enable the server to
//! steal or siphon off funds. It could, however, reduce the client's privacy by forcing all
//! payments to be routed via channels the server controls.
//!
//! The way a server is meant to calculate this rapid gossip sync data is by using a `latest_seen`
//! timestamp provided by the client. It's not included in either channel announcement or update,
//! (not least due to announcements not including any timestamps at all, but only a block height)
//! but rather, it's a timestamp of when the server saw a particular message.
//! [sync_network_graph_with_file_path]: RapidGossipSync::sync_network_graph_with_file_path
// Allow and import test features for benching
#![cfg_attr(all(test, feature = "_bench_unstable"), feature(test))]
#[cfg(all(test, feature = "_bench_unstable"))]
extern crate test;
#[cfg(feature = "std")]
use std::fs::File;
use std::ops::Deref;
use std::sync::atomic::{AtomicBool, Ordering};
use core::ops::Deref;
use core::sync::atomic::{AtomicBool, Ordering};
use lightning::io;
use lightning::routing::gossip::NetworkGraph;
use lightning::util::logger::Logger;
use crate::error::GraphSyncError;
pub use crate::error::GraphSyncError;
/// Error types that these functions can return
pub mod error;
mod error;
/// Core functionality of this crate
pub mod processing;
mod processing;
/// Rapid Gossip Sync struct
/// The main Rapid Gossip Sync object.
///
/// See [crate-level documentation] for usage.
///
/// [crate-level documentation]: crate
@ -94,7 +94,7 @@ where L::Target: Logger {
}
impl<NG: Deref<Target=NetworkGraph<L>>, L: Deref> RapidGossipSync<NG, L> where L::Target: Logger {
/// Instantiate a new [`RapidGossipSync`] instance
/// Instantiate a new [`RapidGossipSync`] instance.
pub fn new(network_graph: NG) -> Self {
Self {
network_graph,
@ -102,13 +102,14 @@ impl<NG: Deref<Target=NetworkGraph<L>>, L: Deref> RapidGossipSync<NG, L> where L
}
}
/// Sync gossip data from a file
/// Sync gossip data from a file.
/// Returns the last sync timestamp to be used the next time rapid sync data is queried.
///
/// `network_graph`: The network graph to apply the updates to
///
/// `sync_path`: Path to the file where the gossip update data is located
///
#[cfg(feature = "std")]
pub fn sync_network_graph_with_file_path(
&self,
sync_path: &str,
@ -117,6 +118,17 @@ impl<NG: Deref<Target=NetworkGraph<L>>, L: Deref> RapidGossipSync<NG, L> where L
self.update_network_graph_from_byte_stream(&mut file)
}
/// Update network graph from binary data.
/// Returns the last sync timestamp to be used the next time rapid sync data is queried.
///
/// `network_graph`: network graph to be updated
///
/// `update_data`: `&[u8]` binary stream that comprises the update data
pub fn update_network_graph(&self, update_data: &[u8]) -> Result<u32, GraphSyncError> {
let mut read_cursor = io::Cursor::new(update_data);
self.update_network_graph_from_byte_stream(&mut read_cursor)
}
/// Gets a reference to the underlying [`NetworkGraph`] which was provided in
/// [`RapidGossipSync::new`].
///
@ -125,7 +137,7 @@ impl<NG: Deref<Target=NetworkGraph<L>>, L: Deref> RapidGossipSync<NG, L> where L
&self.network_graph
}
/// Returns whether a rapid gossip sync has completed at least once
/// Returns whether a rapid gossip sync has completed at least once.
pub fn is_initial_sync_complete(&self) -> bool {
self.is_initial_sync_complete.load(Ordering::Acquire)
}

23
lightning-rapid-gossip-sync/src/processing.rs
View file

@ -1,8 +1,6 @@
use std::cmp::max;
use std::io;
use std::io::Read;
use std::ops::Deref;
use std::sync::atomic::Ordering;
use core::cmp::max;
use core::ops::Deref;
use core::sync::atomic::Ordering;
use bitcoin::BlockHash;
use bitcoin::secp256k1::PublicKey;
@ -13,6 +11,7 @@ use lightning::ln::msgs::{
use lightning::routing::gossip::NetworkGraph;
use lightning::util::logger::Logger;
use lightning::util::ser::{BigSize, Readable};
use lightning::io;
use crate::error::GraphSyncError;
use crate::RapidGossipSync;
@ -28,19 +27,7 @@ const GOSSIP_PREFIX: [u8; 4] = [76, 68, 75, 1];
const MAX_INITIAL_NODE_ID_VECTOR_CAPACITY: u32 = 50_000;
impl<NG: Deref<Target=NetworkGraph<L>>, L: Deref> RapidGossipSync<NG, L> where L::Target: Logger {
/// Update network graph from binary data.
/// Returns the last sync timestamp to be used the next time rapid sync data is queried.
///
/// `network_graph`: network graph to be updated
///
/// `update_data`: `&[u8]` binary stream that comprises the update data
pub fn update_network_graph(&self, update_data: &[u8]) -> Result<u32, GraphSyncError> {
let mut read_cursor = io::Cursor::new(update_data);
self.update_network_graph_from_byte_stream(&mut read_cursor)
}
pub(crate) fn update_network_graph_from_byte_stream<R: Read>(
pub(crate) fn update_network_graph_from_byte_stream<R: io::Read>(
&self,
mut read_cursor: &mut R,
) -> Result<u32, GraphSyncError> {

3
no-std-check/Cargo.toml
View file

@ -4,8 +4,9 @@ version = "0.1.0"
edition = "2018"
[features]
default = ["lightning/no-std", "lightning-invoice/no-std"]
default = ["lightning/no-std", "lightning-invoice/no-std", "lightning-rapid-gossip-sync/no-std"]
[dependencies]
lightning = { path = "../lightning", default-features = false }
lightning-invoice = { path = "../lightning-invoice", default-features = false }
lightning-rapid-gossip-sync = { path = "../lightning-rapid-gossip-sync", default-features = false }