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Limit the number of inbound peer connections (#2961) 

* Limit open inbound connections based on the config

* Log inbound connection errors at debug level

* Test inbound connection limits

* Use clone directly in function call argument lists

* Remove an outdated comment

* Update tests to use an unbounded channel rather than mem::forget

And rename some variables.

* Use a lower limit in a slow test and require that it is exceeded
This commit is contained in:
teor 2021-10-28 11:49:31 +10:00 committed by GitHub
parent 8d01750459
commit f26a60b801
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 738 additions and 79 deletions
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57
zebra-network/src/peer_set/initialize.rs
View File

@ -144,6 +144,7 @@ where
// Connect the rx end to a PeerSet, wrapping new peers in load instruments.
let peer_set = PeerSet::new(
&config,
PeakEwmaDiscover::new(
// Discover interprets an error as stream termination,
// so discard any errored connections...
@ -162,19 +163,20 @@ where
// Connect peerset_tx to the 3 peer sources:
//
// 1. Incoming peer connections, via a listener.
let listen_guard = tokio::spawn(
accept_inbound_connections(tcp_listener, listen_handshaker, peerset_tx.clone())
.instrument(Span::current()),
let listen_fut = accept_inbound_connections(
config.clone(),
tcp_listener,
listen_handshaker,
peerset_tx.clone(),
);
let listen_guard = tokio::spawn(listen_fut.instrument(Span::current()));
// 2. Initial peers, specified in the config.
let initial_peers_fut = {
let config = config.clone();
let outbound_connector = outbound_connector.clone();
let peerset_tx = peerset_tx.clone();
add_initial_peers(config, outbound_connector, peerset_tx)
};
let initial_peers_fut = add_initial_peers(
config.clone(),
outbound_connector.clone(),
peerset_tx.clone(),
);
let initial_peers_join = tokio::spawn(initial_peers_fut.instrument(Span::current()));
// 3. Outgoing peers we connect to in response to load.
@ -202,9 +204,7 @@ where
let _ = demand_tx.try_send(MorePeers);
}
let crawl_fut = {
let config = config.clone();
crawl_and_dial(
let crawl_fut = crawl_and_dial(
config,
demand_tx,
demand_rx,
@ -212,8 +212,7 @@ where
outbound_connector,
peerset_tx,
active_outbound_connections,
)
};
);
let crawl_guard = tokio::spawn(crawl_fut.instrument(Span::current()));
handle_tx.send(vec![listen_guard, crawl_guard]).unwrap();
@ -434,8 +433,11 @@ async fn open_listener(config: &Config) -> (TcpListener, SocketAddr) {
///
/// Uses `handshaker` to perform a Zcash network protocol handshake, and sends
/// the [`peer::Client`] result over `peerset_tx`.
#[instrument(skip(listener, handshaker, peerset_tx), fields(listener_addr = ?listener.local_addr()))]
///
/// Limit the number of active inbound connections based on `config`.
#[instrument(skip(config, listener, handshaker, peerset_tx), fields(listener_addr = ?listener.local_addr()))]
async fn accept_inbound_connections<S>(
config: Config,
listener: TcpListener,
mut handshaker: S,
peerset_tx: mpsc::Sender<PeerChange>,
@ -447,8 +449,19 @@ where
let mut active_inbound_connections = ActiveConnectionCounter::new_counter();
loop {
if let Ok((tcp_stream, addr)) = listener.accept().await {
// The peer already opened a connection, so increment the connection count immediately.
let inbound_result = listener.accept().await;
if let Ok((tcp_stream, addr)) = inbound_result {
if active_inbound_connections.update_count()
>= config.peerset_inbound_connection_limit()
{
// Too many open inbound connections or pending handshakes already.
// Close the connection.
std::mem::drop(tcp_stream);
continue;
}
// The peer already opened a connection to us.
// So we want to increment the connection count as soon as possible.
let connection_tracker = active_inbound_connections.track_connection();
debug!(
inbound_connections = ?active_inbound_connections.update_count(),
@ -492,6 +505,8 @@ where
// Zebra can't control how many queued connections are waiting,
// but most OSes also limit the number of queued inbound connections on a listener port.
tokio::time::sleep(constants::MIN_PEER_CONNECTION_INTERVAL).await;
} else {
debug!(?inbound_result, "error accepting inbound connection");
}
// Security: Let other tasks run after each connection is processed.
@ -536,8 +551,8 @@ enum CrawlerAction {
/// permanent internal error. Transient errors and individual peer errors should
/// be handled within the crawler.
///
/// Uses `active_outbound_connections` to track the number of active outbound connections
/// in both the initial peers and crawler.
/// Uses `active_outbound_connections` to limit the number of active outbound connections
/// across both the initial peers and crawler. The limit is based on `config`.
#[instrument(skip(
config,
demand_tx,
@ -606,7 +621,7 @@ where
// turn the demand into an action, based on the crawler's current state
_ = demand_rx.next() => {
if active_outbound_connections.update_count() >= config.peerset_outbound_connection_limit() {
// Too many open connections or pending handshakes already
// Too many open outbound connections or pending handshakes already
DemandDrop
} else if let Some(candidate) = candidates.next().await {
// candidates.next has a short delay, and briefly holds the address

725
zebra-network/src/peer_set/initialize/tests/vectors.rs
View File

@ -24,7 +24,7 @@ use futures::{
channel::{mpsc, oneshot},
FutureExt, StreamExt,
};
use tokio::task::JoinHandle;
use tokio::{net::TcpStream, task::JoinHandle};
use tower::{discover::Change, service_fn, Service};
use tracing::Span;
@ -34,9 +34,12 @@ use zebra_test::net::random_known_port;
use crate::{
constants, init,
meta_addr::MetaAddr,
peer::{self, ErrorSlot, OutboundConnectorRequest},
peer::{self, ErrorSlot, HandshakeRequest, OutboundConnectorRequest},
peer_set::{
initialize::{add_initial_peers, crawl_and_dial, PeerChange},
initialize::{
accept_inbound_connections, add_initial_peers, crawl_and_dial, open_listener,
PeerChange,
},
set::MorePeers,
ActiveConnectionCounter, CandidateSet,
},
@ -51,12 +54,17 @@ use Network::*;
/// Using a very short time can make the crawler not run at all.
const CRAWLER_TEST_DURATION: Duration = Duration::from_secs(10);
/// The amount of time to run the listener, before testing what it has done.
///
/// Using a very short time can make the listener not run at all.
const LISTENER_TEST_DURATION: Duration = Duration::from_secs(10);
/// Test that zebra-network discovers dynamic bind-to-all-interfaces listener ports,
/// and sends them to the `AddressBook`.
///
/// Note: This test doesn't cover local interface or public IP address discovery.
#[tokio::test]
async fn local_listener_unspecified_port_unspecified_addr() {
async fn local_listener_unspecified_port_unspecified_addr_v4() {
zebra_test::init();
if zebra_test::net::zebra_skip_network_tests() {
@ -67,6 +75,19 @@ async fn local_listener_unspecified_port_unspecified_addr() {
// (localhost should be enough)
local_listener_port_with("0.0.0.0:0".parse().unwrap(), Mainnet).await;
local_listener_port_with("0.0.0.0:0".parse().unwrap(), Testnet).await;
}
/// Test that zebra-network discovers dynamic bind-to-all-interfaces listener ports,
/// and sends them to the `AddressBook`.
///
/// Note: This test doesn't cover local interface or public IP address discovery.
#[tokio::test]
async fn local_listener_unspecified_port_unspecified_addr_v6() {
zebra_test::init();
if zebra_test::net::zebra_skip_network_tests() {
return;
}
if zebra_test::net::zebra_skip_ipv6_tests() {
return;
@ -80,7 +101,7 @@ async fn local_listener_unspecified_port_unspecified_addr() {
/// Test that zebra-network discovers dynamic localhost listener ports,
/// and sends them to the `AddressBook`.
#[tokio::test]
async fn local_listener_unspecified_port_localhost_addr() {
async fn local_listener_unspecified_port_localhost_addr_v4() {
zebra_test::init();
if zebra_test::net::zebra_skip_network_tests() {
@ -90,6 +111,17 @@ async fn local_listener_unspecified_port_localhost_addr() {
// these tests might fail on machines with unusual IPv4 localhost configs
local_listener_port_with("127.0.0.1:0".parse().unwrap(), Mainnet).await;
local_listener_port_with("127.0.0.1:0".parse().unwrap(), Testnet).await;
}
/// Test that zebra-network discovers dynamic localhost listener ports,
/// and sends them to the `AddressBook`.
#[tokio::test]
async fn local_listener_unspecified_port_localhost_addr_v6() {
zebra_test::init();
if zebra_test::net::zebra_skip_network_tests() {
return;
}
if zebra_test::net::zebra_skip_ipv6_tests() {
return;
@ -102,11 +134,10 @@ async fn local_listener_unspecified_port_localhost_addr() {
/// Test that zebra-network propagates fixed localhost listener ports to the `AddressBook`.
#[tokio::test]
async fn local_listener_fixed_port_localhost_addr() {
async fn local_listener_fixed_port_localhost_addr_v4() {
zebra_test::init();
let localhost_v4 = "127.0.0.1".parse().unwrap();
let localhost_v6 = "::1".parse().unwrap();
if zebra_test::net::zebra_skip_network_tests() {
return;
@ -114,6 +145,18 @@ async fn local_listener_fixed_port_localhost_addr() {
local_listener_port_with(SocketAddr::new(localhost_v4, random_known_port()), Mainnet).await;
local_listener_port_with(SocketAddr::new(localhost_v4, random_known_port()), Testnet).await;
}
/// Test that zebra-network propagates fixed localhost listener ports to the `AddressBook`.
#[tokio::test]
async fn local_listener_fixed_port_localhost_addr_v6() {
zebra_test::init();
let localhost_v6 = "::1".parse().unwrap();
if zebra_test::net::zebra_skip_network_tests() {
return;
}
if zebra_test::net::zebra_skip_ipv6_tests() {
return;
@ -253,10 +296,10 @@ async fn crawler_peer_limit_zero_connect_panic() {
unreachable!("outbound connector should never be called with a zero peer limit")
});
let (_config, mut peerset_tx) =
let (_config, mut peerset_rx) =
spawn_crawler_with_peer_limit(0, unreachable_outbound_connector).await;
let peer_result = peerset_tx.try_next();
let peer_result = peerset_rx.try_next();
assert!(
// `Err(_)` means that no peers are available, and the sender has not been dropped.
// `Ok(None)` means that no peers are available, and the sender has been dropped.
@ -277,10 +320,10 @@ async fn crawler_peer_limit_one_connect_error() {
let error_outbound_connector =
service_fn(|_| async { Err("test outbound connector always returns errors".into()) });
let (_config, mut peerset_tx) =
let (_config, mut peerset_rx) =
spawn_crawler_with_peer_limit(1, error_outbound_connector).await;
let peer_result = peerset_tx.try_next();
let peer_result = peerset_rx.try_next();
assert!(
// `Err(_)` means that no peers are available, and the sender has not been dropped.
// `Ok(None)` means that no peers are available, and the sender has been dropped.
@ -325,12 +368,12 @@ async fn crawler_peer_limit_one_connect_ok_then_drop() {
Ok(Change::Insert(addr, fake_client))
});
let (config, mut peerset_tx) =
let (config, mut peerset_rx) =
spawn_crawler_with_peer_limit(1, success_disconnect_outbound_connector).await;
let mut peer_count: usize = 0;
loop {
let peer_result = peerset_tx.try_next();
let peer_result = peerset_rx.try_next();
match peer_result {
// A peer handshake succeeded.
Ok(Some(peer_result)) => {
@ -368,8 +411,11 @@ async fn crawler_peer_limit_one_connect_ok_stay_open() {
// This test does not require network access, because the outbound connector
// and peer set are fake.
let success_stay_open_outbound_connector =
service_fn(|req: OutboundConnectorRequest| async move {
let (peer_tracker_tx, mut peer_tracker_rx) = mpsc::unbounded();
let success_stay_open_outbound_connector = service_fn(move |req: OutboundConnectorRequest| {
let peer_tracker_tx = peer_tracker_tx.clone();
async move {
let OutboundConnectorRequest {
addr,
connection_tracker,
@ -385,29 +431,49 @@ async fn crawler_peer_limit_one_connect_ok_stay_open() {
error_slot,
};
// Fake the connection being open forever.
std::mem::forget(connection_tracker);
// Make the connection staying open.
peer_tracker_tx
.unbounded_send(connection_tracker)
.expect("unexpected error sending to unbounded channel");
Ok(Change::Insert(addr, fake_client))
}
});
let (config, mut peerset_tx) =
let (config, mut peerset_rx) =
spawn_crawler_with_peer_limit(1, success_stay_open_outbound_connector).await;
let mut peer_count: usize = 0;
let mut peer_change_count: usize = 0;
loop {
let peer_result = peerset_tx.try_next();
match peer_result {
let peer_change_result = peerset_rx.try_next();
match peer_change_result {
// A peer handshake succeeded.
Ok(Some(peer_result)) => {
Ok(Some(peer_change_result)) => {
assert!(
matches!(peer_result, Ok(Change::Insert(_, _))),
matches!(peer_change_result, Ok(Change::Insert(_, _))),
"unexpected connection error: {:?}\n\
{} previous peers succeeded",
peer_result,
peer_count,
peer_change_result,
peer_change_count,
);
peer_count += 1;
peer_change_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
let mut peer_tracker_count: usize = 0;
loop {
let peer_tracker_result = peer_tracker_rx.try_next();
match peer_tracker_result {
// We held this peer tracker open until now.
Ok(Some(peer_tracker)) => {
std::mem::drop(peer_tracker);
peer_tracker_count += 1;
}
// The channel is closed and there are no messages left in the channel.
@ -418,10 +484,19 @@ async fn crawler_peer_limit_one_connect_ok_stay_open() {
}
assert!(
peer_count <= config.peerset_outbound_connection_limit(),
"unexpected number of peer connections {}, over limit of {}",
peer_count,
peer_change_count <= config.peerset_outbound_connection_limit(),
"unexpected number of peer changes {}, over limit of {}, had {} peer trackers",
peer_change_count,
config.peerset_outbound_connection_limit(),
peer_tracker_count,
);
assert!(
peer_tracker_count <= config.peerset_outbound_connection_limit(),
"unexpected number of peer trackers {}, over limit of {}, had {} peer changes",
peer_tracker_count,
config.peerset_outbound_connection_limit(),
peer_change_count,
);
}
@ -436,10 +511,10 @@ async fn crawler_peer_limit_default_connect_error() {
let error_outbound_connector =
service_fn(|_| async { Err("test outbound connector always returns errors".into()) });
let (_config, mut peerset_tx) =
let (_config, mut peerset_rx) =
spawn_crawler_with_peer_limit(None, error_outbound_connector).await;
let peer_result = peerset_tx.try_next();
let peer_result = peerset_rx.try_next();
assert!(
// `Err(_)` means that no peers are available, and the sender has not been dropped.
// `Ok(None)` means that no peers are available, and the sender has been dropped.
@ -484,12 +559,14 @@ async fn crawler_peer_limit_default_connect_ok_then_drop() {
Ok(Change::Insert(addr, fake_client))
});
let (config, mut peerset_tx) =
spawn_crawler_with_peer_limit(None, success_disconnect_outbound_connector).await;
// TODO: tweak the crawler timeouts and rate-limits so we get over the actual limit
// (currently, getting over the limit can take 30 seconds or more)
let (config, mut peerset_rx) =
spawn_crawler_with_peer_limit(15, success_disconnect_outbound_connector).await;
let mut peer_count: usize = 0;
loop {
let peer_result = peerset_tx.try_next();
let peer_result = peerset_rx.try_next();
match peer_result {
// A peer handshake succeeded.
Ok(Some(peer_result)) => {
@ -510,14 +587,11 @@ async fn crawler_peer_limit_default_connect_ok_then_drop() {
}
}
// TODO: tweak the crawler timeouts and rate-limits so we get over the actual limit
// (currently, getting over the limit can take 30 seconds or more)
let lower_limit = config.peerset_outbound_connection_limit() / 3;
assert!(
peer_count > lower_limit,
peer_count > config.peerset_outbound_connection_limit(),
"unexpected number of peer connections {}, should be over the limit of {}",
peer_count,
lower_limit,
config.peerset_outbound_connection_limit(),
);
}
@ -530,8 +604,11 @@ async fn crawler_peer_limit_default_connect_ok_stay_open() {
// This test does not require network access, because the outbound connector
// and peer set are fake.
let success_stay_open_outbound_connector =
service_fn(|req: OutboundConnectorRequest| async move {
let (peer_tracker_tx, mut peer_tracker_rx) = mpsc::unbounded();
let success_stay_open_outbound_connector = service_fn(move |req: OutboundConnectorRequest| {
let peer_tracker_tx = peer_tracker_tx.clone();
async move {
let OutboundConnectorRequest {
addr,
connection_tracker,
@ -547,19 +624,173 @@ async fn crawler_peer_limit_default_connect_ok_stay_open() {
error_slot,
};
// Fake the connection being open forever.
std::mem::forget(connection_tracker);
// Make the connection staying open.
peer_tracker_tx
.unbounded_send(connection_tracker)
.expect("unexpected error sending to unbounded channel");
Ok(Change::Insert(addr, fake_client))
}
});
// The initial target size is multiplied by 1.5 to give the actual limit.
let (config, mut peerset_tx) =
let (config, mut peerset_rx) =
spawn_crawler_with_peer_limit(None, success_stay_open_outbound_connector).await;
let mut peer_change_count: usize = 0;
loop {
let peer_change_result = peerset_rx.try_next();
match peer_change_result {
// A peer handshake succeeded.
Ok(Some(peer_change_result)) => {
assert!(
matches!(peer_change_result, Ok(Change::Insert(_, _))),
"unexpected connection error: {:?}\n\
{} previous peers succeeded",
peer_change_result,
peer_change_count,
);
peer_change_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
let mut peer_tracker_count: usize = 0;
loop {
let peer_tracker_result = peer_tracker_rx.try_next();
match peer_tracker_result {
// We held this peer tracker open until now.
Ok(Some(peer_tracker)) => {
std::mem::drop(peer_tracker);
peer_tracker_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
assert!(
peer_change_count <= config.peerset_outbound_connection_limit(),
"unexpected number of peer changes {}, over limit of {}, had {} peer trackers",
peer_change_count,
config.peerset_outbound_connection_limit(),
peer_tracker_count,
);
assert!(
peer_tracker_count <= config.peerset_outbound_connection_limit(),
"unexpected number of peer trackers {}, over limit of {}, had {} peer changes",
peer_tracker_count,
config.peerset_outbound_connection_limit(),
peer_change_count,
);
}
/// Test the listener with an inbound peer limit of zero peers, and a handshaker that panics.
#[tokio::test]
async fn listener_peer_limit_zero_handshake_panic() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let unreachable_inbound_handshaker = service_fn(|_| async {
unreachable!("inbound handshaker should never be called with a zero peer limit")
});
let (_config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(0, unreachable_inbound_handshaker).await;
let peer_result = peerset_rx.try_next();
assert!(
// `Err(_)` means that no peers are available, and the sender has not been dropped.
// `Ok(None)` means that no peers are available, and the sender has been dropped.
matches!(peer_result, Err(_) | Ok(None)),
"unexpected peer when inbound limit is zero: {:?}",
peer_result,
);
}
/// Test the listener with an inbound peer limit of one peer, and a handshaker that always errors.
#[tokio::test]
async fn listener_peer_limit_one_handshake_error() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let error_inbound_handshaker =
service_fn(|_| async { Err("test inbound handshaker always returns errors".into()) });
let (_config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(1, error_inbound_handshaker).await;
let peer_result = peerset_rx.try_next();
assert!(
// `Err(_)` means that no peers are available, and the sender has not been dropped.
// `Ok(None)` means that no peers are available, and the sender has been dropped.
matches!(peer_result, Err(_) | Ok(None)),
"unexpected peer when all handshakes error: {:?}",
peer_result,
);
}
/// Test the listener with an inbound peer limit of one peer,
/// and a handshaker that returns success then disconnects the peer.
#[tokio::test]
async fn listener_peer_limit_one_handshake_ok_then_drop() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let success_disconnect_inbound_handshaker = service_fn(|req: HandshakeRequest| async move {
let HandshakeRequest {
tcp_stream,
connected_addr: _,
connection_tracker,
} = req;
let (server_tx, _server_rx) = mpsc::channel(0);
let (shutdown_tx, _shutdown_rx) = oneshot::channel();
let error_slot = ErrorSlot::default();
let fake_client = peer::Client {
shutdown_tx: Some(shutdown_tx),
server_tx,
error_slot,
};
// Actually close the connection.
std::mem::drop(connection_tracker);
std::mem::drop(tcp_stream);
// Give the crawler time to get the message.
tokio::task::yield_now().await;
Ok(fake_client)
});
let (config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(1, success_disconnect_inbound_handshaker).await;
let mut peer_count: usize = 0;
loop {
let peer_result = peerset_tx.try_next();
let peer_result = peerset_rx.try_next();
match peer_result {
// A peer handshake succeeded.
Ok(Some(peer_result)) => {
@ -581,10 +812,312 @@ async fn crawler_peer_limit_default_connect_ok_stay_open() {
}
assert!(
peer_count <= config.peerset_outbound_connection_limit(),
"unexpected number of peer connections {}, over limit of {}",
peer_count > config.peerset_inbound_connection_limit(),
"unexpected number of peer connections {}, should be over the limit of {}",
peer_count,
config.peerset_outbound_connection_limit(),
config.peerset_inbound_connection_limit(),
);
}
/// Test the listener with an inbound peer limit of one peer,
/// and a handshaker that returns success then holds the peer open.
#[tokio::test]
async fn listener_peer_limit_one_handshake_ok_stay_open() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let (peer_tracker_tx, mut peer_tracker_rx) = mpsc::unbounded();
let success_stay_open_inbound_handshaker = service_fn(move |req: HandshakeRequest| {
let peer_tracker_tx = peer_tracker_tx.clone();
async move {
let HandshakeRequest {
tcp_stream,
connected_addr: _,
connection_tracker,
} = req;
let (server_tx, _server_rx) = mpsc::channel(0);
let (shutdown_tx, _shutdown_rx) = oneshot::channel();
let error_slot = ErrorSlot::default();
let fake_client = peer::Client {
shutdown_tx: Some(shutdown_tx),
server_tx,
error_slot,
};
// Make the connection staying open.
peer_tracker_tx
.unbounded_send((tcp_stream, connection_tracker))
.expect("unexpected error sending to unbounded channel");
Ok(fake_client)
}
});
let (config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(1, success_stay_open_inbound_handshaker).await;
let mut peer_change_count: usize = 0;
loop {
let peer_change_result = peerset_rx.try_next();
match peer_change_result {
// A peer handshake succeeded.
Ok(Some(peer_change_result)) => {
assert!(
matches!(peer_change_result, Ok(Change::Insert(_, _))),
"unexpected connection error: {:?}\n\
{} previous peers succeeded",
peer_change_result,
peer_change_count,
);
peer_change_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
let mut peer_tracker_count: usize = 0;
loop {
let peer_tracker_result = peer_tracker_rx.try_next();
match peer_tracker_result {
// We held this peer connection and tracker open until now.
Ok(Some((peer_connection, peer_tracker))) => {
std::mem::drop(peer_connection);
std::mem::drop(peer_tracker);
peer_tracker_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
assert!(
peer_change_count <= config.peerset_inbound_connection_limit(),
"unexpected number of peer changes {}, over limit of {}, had {} peer trackers",
peer_change_count,
config.peerset_inbound_connection_limit(),
peer_tracker_count,
);
assert!(
peer_tracker_count <= config.peerset_inbound_connection_limit(),
"unexpected number of peer trackers {}, over limit of {}, had {} peer changes",
peer_tracker_count,
config.peerset_inbound_connection_limit(),
peer_change_count,
);
}
/// Test the listener with the default inbound peer limit, and a handshaker that always errors.
#[tokio::test]
async fn listener_peer_limit_default_handshake_error() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let error_inbound_handshaker =
service_fn(|_| async { Err("test inbound handshaker always returns errors".into()) });
let (_config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(None, error_inbound_handshaker).await;
let peer_result = peerset_rx.try_next();
assert!(
// `Err(_)` means that no peers are available, and the sender has not been dropped.
// `Ok(None)` means that no peers are available, and the sender has been dropped.
matches!(peer_result, Err(_) | Ok(None)),
"unexpected peer when all handshakes error: {:?}",
peer_result,
);
}
/// Test the listener with the default inbound peer limit,
/// and a handshaker that returns success then disconnects the peer.
#[tokio::test]
async fn listener_peer_limit_default_handshake_ok_then_drop() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let success_disconnect_inbound_handshaker = service_fn(|req: HandshakeRequest| async move {
let HandshakeRequest {
tcp_stream,
connected_addr: _,
connection_tracker,
} = req;
let (server_tx, _server_rx) = mpsc::channel(0);
let (shutdown_tx, _shutdown_rx) = oneshot::channel();
let error_slot = ErrorSlot::default();
let fake_client = peer::Client {
shutdown_tx: Some(shutdown_tx),
server_tx,
error_slot,
};
// Actually close the connection.
std::mem::drop(connection_tracker);
std::mem::drop(tcp_stream);
// Give the crawler time to get the message.
tokio::task::yield_now().await;
Ok(fake_client)
});
let (config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(None, success_disconnect_inbound_handshaker).await;
let mut peer_count: usize = 0;
loop {
let peer_result = peerset_rx.try_next();
match peer_result {
// A peer handshake succeeded.
Ok(Some(peer_result)) => {
assert!(
matches!(peer_result, Ok(Change::Insert(_, _))),
"unexpected connection error: {:?}\n\
{} previous peers succeeded",
peer_result,
peer_count,
);
peer_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
assert!(
peer_count > config.peerset_inbound_connection_limit(),
"unexpected number of peer connections {}, should be over the limit of {}",
peer_count,
config.peerset_inbound_connection_limit(),
);
}
/// Test the listener with the default inbound peer limit,
/// and a handshaker that returns success then holds the peer open.
#[tokio::test]
async fn listener_peer_limit_default_handshake_ok_stay_open() {
zebra_test::init();
// This test requires an IPv4 network stack with 127.0.0.1 as localhost.
if zebra_test::net::zebra_skip_network_tests() {
return;
}
let (peer_tracker_tx, mut peer_tracker_rx) = mpsc::unbounded();
let success_stay_open_inbound_handshaker = service_fn(move |req: HandshakeRequest| {
let peer_tracker_tx = peer_tracker_tx.clone();
async move {
let HandshakeRequest {
tcp_stream,
connected_addr: _,
connection_tracker,
} = req;
let (server_tx, _server_rx) = mpsc::channel(0);
let (shutdown_tx, _shutdown_rx) = oneshot::channel();
let error_slot = ErrorSlot::default();
let fake_client = peer::Client {
shutdown_tx: Some(shutdown_tx),
server_tx,
error_slot,
};
// Make the connection staying open.
peer_tracker_tx
.unbounded_send((tcp_stream, connection_tracker))
.expect("unexpected error sending to unbounded channel");
Ok(fake_client)
}
});
let (config, mut peerset_rx) =
spawn_inbound_listener_with_peer_limit(None, success_stay_open_inbound_handshaker).await;
let mut peer_change_count: usize = 0;
loop {
let peer_change_result = peerset_rx.try_next();
match peer_change_result {
// A peer handshake succeeded.
Ok(Some(peer_change_result)) => {
assert!(
matches!(peer_change_result, Ok(Change::Insert(_, _))),
"unexpected connection error: {:?}\n\
{} previous peers succeeded",
peer_change_result,
peer_change_count,
);
peer_change_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
let mut peer_tracker_count: usize = 0;
loop {
let peer_tracker_result = peer_tracker_rx.try_next();
match peer_tracker_result {
// We held this peer connection and tracker open until now.
Ok(Some((peer_connection, peer_tracker))) => {
std::mem::drop(peer_connection);
std::mem::drop(peer_tracker);
peer_tracker_count += 1;
}
// The channel is closed and there are no messages left in the channel.
Ok(None) => break,
// The channel is still open, but there are no messages left in the channel.
Err(_) => break,
}
}
assert!(
peer_change_count <= config.peerset_inbound_connection_limit(),
"unexpected number of peer changes {}, over limit of {}, had {} peer trackers",
peer_change_count,
config.peerset_inbound_connection_limit(),
peer_tracker_count,
);
assert!(
peer_tracker_count <= config.peerset_inbound_connection_limit(),
"unexpected number of peer trackers {}, over limit of {}, had {} peer changes",
peer_tracker_count,
config.peerset_inbound_connection_limit(),
peer_change_count,
);
}
@ -801,6 +1334,102 @@ where
(config, peerset_rx)
}
/// Run an inbound peer listener with `peerset_initial_target_size` and `handshaker`.
///
/// Uses the default values for all other config fields.
///
/// Returns the generated [`Config`], and the peer set receiver.
async fn spawn_inbound_listener_with_peer_limit<S>(
peerset_initial_target_size: impl Into<Option<usize>>,
listen_handshaker: S,
) -> (Config, mpsc::Receiver<PeerChange>)
where
S: Service<peer::HandshakeRequest, Response = peer::Client, Error = BoxError>
+ Clone
+ Send
+ 'static,
S::Future: Send + 'static,
{
// Create a test config that listens on any unused port.
let listen_addr = "127.0.0.1:0".parse().unwrap();
let mut config = Config {
listen_addr,
..Config::default()
};
if let Some(peerset_initial_target_size) = peerset_initial_target_size.into() {
config.peerset_initial_target_size = peerset_initial_target_size;
}
// Open the listener port.
let (tcp_listener, listen_addr) = open_listener(&config.clone()).await;
// Make enough inbound connections to go over the limit, even if the limit is zero.
// Make the channels large enough to hold all the connections.
let over_limit_connections = config.peerset_inbound_connection_limit() * 2 + 1;
let (peerset_tx, peerset_rx) = mpsc::channel::<PeerChange>(over_limit_connections);
// Start listening for connections.
let listen_fut = accept_inbound_connections(
config.clone(),
tcp_listener,
listen_handshaker,
peerset_tx.clone(),
);
let listen_task_handle = tokio::spawn(listen_fut);
// Open inbound connections.
let mut outbound_task_handles = Vec::new();
for _ in 0..over_limit_connections {
let outbound_fut = async move {
let outbound_result = TcpStream::connect(listen_addr).await;
// Let other tasks run before we block on reading.
tokio::task::yield_now().await;
if let Ok(outbound_stream) = outbound_result {
// Wait until the listener closes the connection.
// The handshaker is fake, so it never sends any data.
let readable_result = outbound_stream.readable().await;
info!(
?readable_result,
"outbound connection became readable or errored: \
closing connection to test inbound listener"
);
} else {
// If the connection is closed quickly, we might get errors here.
debug!(
?outbound_result,
"outbound connection error in inbound listener test"
);
}
};
let outbound_task_handle = tokio::spawn(outbound_fut);
outbound_task_handles.push(outbound_task_handle);
}
// Let the listener run for a while.
tokio::time::sleep(LISTENER_TEST_DURATION).await;
// Stop the listener and outbound tasks, and let them finish.
listen_task_handle.abort();
for outbound_task_handle in outbound_task_handles {
outbound_task_handle.abort();
}
tokio::task::yield_now().await;
// Check for panics or errors in the listener.
let listen_result = listen_task_handle.now_or_never();
assert!(
matches!(listen_result, None)
|| matches!(listen_result, Some(Err(ref e)) if e.is_cancelled()),
"unexpected error or panic in inbound peer listener task: {:?}",
listen_result,
);
(config, peerset_rx)
}
/// Initialize a task that connects to `peer_count` initial peers using the
/// given connector.
///

17
zebra-network/src/peer_set/set.rs
View File

@ -80,7 +80,7 @@ use crate::{
external::InventoryHash,
internal::{Request, Response},
},
AddressBook, BoxError,
AddressBook, BoxError, Config,
};
/// A signal sent by the [`PeerSet`] when it has no ready peers, and gets a request from Zebra.
@ -134,6 +134,8 @@ where
///
/// Used for logging diagnostics.
address_book: Arc<std::sync::Mutex<AddressBook>>,
/// The configured limit for inbound and outbound connections.
peerset_total_connection_limit: usize,
}
impl<D> PeerSet<D>
@ -147,6 +149,7 @@ where
{
/// Construct a peerset which uses `discover` internally.
pub fn new(
config: &Config,
discover: D,
demand_signal: mpsc::Sender<MorePeers>,
handle_rx: tokio::sync::oneshot::Receiver<Vec<JoinHandle<Result<(), BoxError>>>>,
@ -165,6 +168,7 @@ where
inventory_registry: InventoryRegistry::new(inv_stream),
last_peer_log: None,
address_book,
peerset_total_connection_limit: config.peerset_total_connection_limit(),
}
}
@ -432,6 +436,17 @@ where
metrics::gauge!("pool.num_ready", num_ready as f64);
metrics::gauge!("pool.num_unready", num_unready as f64);
metrics::gauge!("zcash.net.peers", num_peers as f64);
// Security: make sure we haven't exceeded the connection limit
if num_peers > self.peerset_total_connection_limit {
let address_metrics = self.address_book.lock().unwrap().address_metrics();
panic!(
"unexpectedly exceeded configured peer set connection limit: \n\
peers: {:?}, ready: {:?}, unready: {:?}, \n\
address_metrics: {:?}",
num_peers, num_ready, num_unready, address_metrics,
);
}
}
}