seed command

zebra-network/src/config.rs

@@ -1,4 +1,8 @@
-use std::{net::SocketAddr, time::Duration};
+use std::{
+    net::{SocketAddr, ToSocketAddrs},
+    string::String,
+    time::Duration,
+};
 
 use crate::network::Network;
 
@@ -8,38 +12,81 @@ use crate::network::Network;
 pub struct Config {
     /// The address on which this node should listen for connections.
     pub listen_addr: SocketAddr,
+
     /// The network to connect to.
     pub network: Network,
+
     /// The user-agent to advertise.
     pub user_agent: String,
-    /// A list of initial peers for the peerset.
-    ///
-    /// XXX this should be replaced with DNS names, not SocketAddrs
-    pub initial_peers: Vec<SocketAddr>,
+
+    /// A list of initial peers for the peerset when operating on
+    /// mainnet.
+    pub initial_mainnet_peers: Vec<String>,
+
+    /// A list of initial peers for the peerset when operating on
+    /// testnet.
+    pub initial_testnet_peers: Vec<String>,
+
     /// The outgoing request buffer size for the peer set.
     pub peerset_request_buffer_size: usize,
 
     // Note: due to the way this is rendered by the toml
     // serializer, the Duration fields should come last.
     /// The default RTT estimate for peer responses, used in load-balancing.
     pub ewma_default_rtt: Duration,
+
     /// The decay time for the exponentially-weighted moving average response time.
     pub ewma_decay_time: Duration,
+
     /// The timeout for peer handshakes.
     pub handshake_timeout: Duration,
+
     /// How frequently we attempt to connect to a new peer.
     pub new_peer_interval: Duration,
 }
 
+impl Config {
+    fn parse_peers<S: ToSocketAddrs>(peers: Vec<S>) -> Vec<SocketAddr> {
+        peers
+            .iter()
+            .flat_map(|s| s.to_socket_addrs())
+            .flatten()
+            .collect::<Vec<SocketAddr>>()
+    }
+
+    /// Get the initial seed peers based on the configured network.
+    pub fn initial_peers(&self) -> Vec<SocketAddr> {
+        match self.network {
+            Network::Mainnet => Config::parse_peers(self.initial_mainnet_peers.clone()),
+            Network::Testnet => Config::parse_peers(self.initial_testnet_peers.clone()),
+        }
+    }
+}
+
 impl Default for Config {
     fn default() -> Config {
+        let mainnet_peers = [
+            "dnsseed.z.cash:8233",
+            "dnsseed.str4d.xyz:8233",
+            "dnsseed.znodes.org:8233",
+        ]
+        .iter()
+        .map(|&s| String::from(s))
+        .collect();
+
+        let testnet_peers = ["dnsseed.testnet.z.cash:18233"]
+            .iter()
+            .map(|&s| String::from(s))
+            .collect();
+
         Config {
             listen_addr: "127.0.0.1:28233"
                 .parse()
                 .expect("Hardcoded address should be parseable"),
             user_agent: crate::constants::USER_AGENT.to_owned(),
             network: Network::Mainnet,
-            initial_peers: Vec::new(),
+            initial_mainnet_peers: mainnet_peers,
+            initial_testnet_peers: testnet_peers,
             ewma_default_rtt: Duration::from_secs(1),
             ewma_decay_time: Duration::from_secs(60),
             peerset_request_buffer_size: 1,

zebra-network/src/peer/server.rs

@@ -304,6 +304,7 @@ where
         // and try to construct an appropriate request object.
         let req = match msg {
             Message::Addr(addrs) => Some(Request::PushPeers(addrs)),
+            Message::GetAddr => Some(Request::GetPeers),
             _ => {
                 debug!("unhandled message type");
                 None

zebra-network/src/peer_set.rs

@@ -103,7 +103,7 @@ where
 
     // 1. Initial peers, specified in the config.
     tokio::spawn(add_initial_peers(
-        config.initial_peers.clone(),
+        config.initial_peers(),
         connector.clone(),
         peerset_tx.clone(),
     ));

zebrad/src/commands.rs

@@ -1,21 +1,14 @@
 //! Zebrad Subcommands
-//!
-//! This is where you specify the subcommands of your application.
-//!
-//! The default application comes with two subcommands:
-//!
-//! - `start`: launches the application
-//! - `version`: print application version
-//!
-//! See the `impl Configurable` below for how to specify the path to the
-//! application's configuration file.
 
 mod config;
 mod connect;
+mod seed;
 mod start;
 mod version;
 
-use self::{config::ConfigCmd, connect::ConnectCmd, start::StartCmd, version::VersionCmd};
+use self::{
+    config::ConfigCmd, connect::ConnectCmd, seed::SeedCmd, start::StartCmd, version::VersionCmd,
+};
 use crate::config::ZebradConfig;
 use abscissa_core::{
     config::Override, Command, Configurable, FrameworkError, Help, Options, Runnable,
@@ -47,6 +40,10 @@ pub enum ZebradCmd {
     /// The `connect` subcommand
     #[options(help = "testing stub for dumping network messages")]
     Connect(ConnectCmd),
+
+    /// The `seed` subcommand
+    #[options(help = "dns seeder")]
+    Seed(SeedCmd),
 }
 
 /// This trait allows you to define how application configuration is loaded.

zebrad/src/commands/config.rs

@@ -27,7 +27,7 @@ impl Runnable for ConfigCmd {
 # can be found in Rustdoc. XXX add link to rendered docs.
 
 "
-        .to_owned();
+        .to_owned(); // The default name and location of the config file is defined in ../commands.rs
         output += &toml::to_string_pretty(&default_config)
             .expect("default config should be serializable");
         match self.output_file {

zebrad/src/commands/connect.rs

@@ -66,9 +66,7 @@ impl ConnectCmd {
             1,
         );
 
-        let mut config = app_config().network.clone();
-
-        config.initial_peers = vec![self.addr];
+        let config = app_config().network.clone();
 
         let (mut peer_set, address_book) = zebra_network::init(config, node).await;
 

zebrad/src/commands/seed.rs

@@ -0,0 +1,155 @@
+//! `seed` subcommand - runs a dns seeder
+
+use std::{
+    future::Future,
+    pin::Pin,
+    sync::{Arc, Mutex},
+    task::{Context, Poll},
+};
+
+use abscissa_core::{config, Command, FrameworkError, Options, Runnable};
+use futures::channel::oneshot;
+use tower::{buffer::Buffer, Service, ServiceExt};
+use zebra_network::{AddressBook, BoxedStdError, Request, Response};
+
+use crate::{config::ZebradConfig, prelude::*};
+
+/// Whether our `SeedService` is poll_ready or not.
+#[derive(Debug)]
+enum SeederState {
+    /// Waiting for the address book to be shared with us via the oneshot channel.
+    AwaitingAddressBook(oneshot::Receiver<Arc<Mutex<AddressBook>>>),
+    /// Address book received, ready to service requests.
+    Ready(Arc<Mutex<AddressBook>>),
+}
+
+#[derive(Debug)]
+struct SeedService {
+    state: SeederState,
+}
+
+impl Service<Request> for SeedService {
+    type Response = Response;
+    type Error = BoxedStdError;
+    type Future =
+        Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send + 'static>>;
+
+    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        debug!("SeedService.state: {:?}", self.state);
+
+        match self.state {
+            SeederState::Ready(_) => return Poll::Ready(Ok(())),
+            SeederState::AwaitingAddressBook(ref mut rx) => match rx.try_recv() {
+                Err(e) => {
+                    error!("SeedService oneshot sender dropped: {:?}", e);
+                    return Poll::Ready(Err(e.into()));
+                }
+                Ok(None) => {
+                    trace!("SeedService hasn't received a message via the oneshot yet.");
+                    return Poll::Pending;
+                }
+                Ok(Some(address_book)) => {
+                    info!(
+                        "SeedService received address_book via oneshot {:?}",
+                        address_book
+                    );
+                    self.state = SeederState::Ready(address_book);
+                    return Poll::Ready(Ok(()));
+                }
+            },
+        }
+    }
+
+    fn call(&mut self, req: Request) -> Self::Future {
+        info!("SeedService handling a request: {:?}", req);
+
+        let address_book = if let SeederState::Ready(address_book) = &self.state {
+            address_book
+        } else {
+            panic!("SeedService::call without SeedService::poll_ready");
+        };
+
+        let response = match req {
+            Request::GetPeers => {
+                debug!(address_book.len = address_book.lock().unwrap().len());
+                info!("SeedService responding to GetPeers");
+                Ok::<Response, Self::Error>(Response::Peers(
+                    address_book.lock().unwrap().peers().collect(),
+                ))
+            }
+            _ => Ok::<Response, Self::Error>(Response::Ok),
+        };
+
+        info!("SeedService response: {:?}", response);
+        return Box::pin(futures::future::ready(response));
+    }
+}
+
+/// `seed` subcommand
+///
+/// A DNS seeder command to spider and collect as many valid peer
+/// addresses as we can.
+// This is not a unit-like struct because it makes Command and Options sad.
+#[derive(Command, Debug, Default, Options)]
+pub struct SeedCmd {}
+
+impl Runnable for SeedCmd {
+    /// Start the application.
+    fn run(&self) {
+        use crate::components::tokio::TokioComponent;
+
+        let _ = app_reader()
+            .state()
+            .components
+            .get_downcast_ref::<TokioComponent>()
+            .expect("TokioComponent should be available")
+            .rt
+            .block_on(self.seed());
+    }
+}
+
+impl SeedCmd {
+    async fn seed(&self) -> Result<(), failure::Error> {
+        use failure::Error;
+
+        info!("begin tower-based peer handling test stub");
+
+        let (addressbook_tx, addressbook_rx) = oneshot::channel();
+        let seed_service = SeedService {
+            state: SeederState::AwaitingAddressBook(addressbook_rx),
+        };
+        let node = Buffer::new(seed_service, 1);
+
+        let config = app_config().network.clone();
+
+        let (mut peer_set, address_book) = zebra_network::init(config, node).await;
+
+        let _ = addressbook_tx.send(address_book);
+
+        info!("waiting for peer_set ready");
+        peer_set.ready().await.map_err(Error::from_boxed_compat)?;
+
+        info!("peer_set became ready");
+
+        #[cfg(dos)]
+        use std::time::Duration;
+        use tokio::timer::Interval;
+
+        #[cfg(dos)]
+        // Fire GetPeers requests at ourselves, for testing.
+        tokio::spawn(async move {
+            let mut interval_stream = Interval::new_interval(Duration::from_secs(1));
+
+            loop {
+                interval_stream.next().await;
+
+                let _ = seed_service.call(Request::GetPeers);
+            }
+        });
+
+        let eternity = tokio::future::pending::<()>();
+        eternity.await;
+
+        Ok(())
+    }
+}