feat(iroh-relay): Rate-limit client connections

This has a hardcoded rate-limiter.  Need to make it configurable.

iroh-relay/Cargo.toml

@@ -99,6 +99,7 @@ clap = { version = "4", features = ["derive"] }
 crypto_box = { version = "0.9.1", features = ["serde", "chacha20"] }
 proptest = "1.2.0"
 rand_chacha = "0.3.1"
+testresult = "0.4.0"
 tokio = { version = "1", features = [
     "io-util",
     "sync",

iroh-relay/src/client/conn.rs

@@ -510,7 +510,7 @@ pub(crate) async fn send_packet<S: Sink<Frame, Error = std::io::Error> + Unpin>(
     };
     if let Some(rate_limiter) = rate_limiter {
         if rate_limiter.check_n(frame.len()).is_err() {
-            tracing::warn!("dropping send: rate limit reached");
+            tracing::debug!("dropping send: rate limit reached");
             return Ok(());
         }
     }
@@ -521,12 +521,7 @@ pub(crate) async fn send_packet<S: Sink<Frame, Error = std::io::Error> + Unpin>(
 }
 
 pub(crate) struct RateLimiter {
-    inner: governor::RateLimiter<
-        governor::state::direct::NotKeyed,
-        governor::state::InMemoryState,
-        governor::clock::DefaultClock,
-        governor::middleware::NoOpMiddleware,
-    >,
+    inner: governor::DefaultDirectRateLimiter,
 }
 
 impl RateLimiter {

iroh-relay/src/protos/disco.rs

@@ -10,6 +10,7 @@ pub(crate) const MAGIC_LEN: usize = MAGIC.as_bytes().len();
 pub(crate) const KEY_LEN: usize = 32;
 
 const MESSAGE_HEADER_LEN: usize = MAGIC_LEN + KEY_LEN;
+
 /// Reports whether p looks like it's a packet containing an encrypted disco message.
 pub fn looks_like_disco_wrapper(p: &[u8]) -> bool {
     if p.len() < MESSAGE_HEADER_LEN {

iroh-relay/src/protos/relay.rs

@@ -18,6 +18,9 @@ use tokio_util::codec::{Decoder, Encoder};
 /// including its on-wire framing overhead)
 pub const MAX_PACKET_SIZE: usize = 64 * 1024;
 
+/// The maximum frame size.
+///
+/// This is also the minimum burst size that a rate-limiter has to accept.
 const MAX_FRAME_SIZE: usize = 1024 * 1024;
 
 /// The Relay magic number, sent in the FrameType::ClientInfo frame upon initial connection.
@@ -200,9 +203,14 @@ pub(crate) async fn recv_client_key<S: Stream<Item = anyhow::Result<Frame>> + Un
     }
 }
 
+/// The protocol for the relay server.
+///
+/// This is a framed protocol, using [`tokio_util::codec`] to turn the streams of bytes into
+/// [`Frame`]s.
 #[derive(Debug, Default, Clone)]
 pub(crate) struct DerpCodec;
 
+/// The frames in the [`DerpCodec`].
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub(crate) enum Frame {
     ClientInfo {
@@ -279,6 +287,11 @@ impl Frame {
         }
     }
 
+    /// Serialized length with frame header.
+    pub(crate) fn len_with_header(&self) -> usize {
+        self.len() + HEADER_LEN
+    }
+
     /// Tries to decode a frame received over websockets.
     ///
     /// Specifically, bytes received from a binary websocket message frame.

iroh-relay/src/server/actor.rs

@@ -183,12 +183,8 @@ impl Actor {
             }
             Message::CreateClient(client_builder) => {
                 inc!(Metrics, accepts);
-
-                trace!(
-                    node_id = client_builder.node_id.fmt_short(),
-                    "create client"
-                );
                 let node_id = client_builder.node_id;
+                trace!(node_id = node_id.fmt_short(), "create client");
 
                 // build and register client, starting up read & write loops for the client
                 // connection