From cd32435d859ef47d282fafa43b0e04e0551db839 Mon Sep 17 00:00:00 2001
From: Darius Clark <dariusc93@users.noreply.github.com>
Date: Sat, 9 Sep 2023 05:37:25 -0400
Subject: [PATCH] fix(ping): honor ping interval in case of errors

This PR adds a delay to ping connection handler after exceeding the failure rate to prevent opening a outbound stream right after an error.

Resolves #4410.

Pull-Request: #4423.
---
 Cargo.lock                     |  2 +-
 Cargo.toml                     |  2 +-
 protocols/ping/CHANGELOG.md    |  8 ++++++++
 protocols/ping/Cargo.toml      |  2 +-
 protocols/ping/src/handler.rs  | 18 +++++++++++-------
 protocols/ping/src/protocol.rs |  3 +--
 6 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 9f0fc338c08..7451366120c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2985,7 +2985,7 @@ dependencies = [
 
 [[package]]
 name = "libp2p-ping"
-version = "0.43.0"
+version = "0.43.1"
 dependencies = [
  "async-std",
  "either",
diff --git a/Cargo.toml b/Cargo.toml
index 734b2d14efb..154bdf38f8e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -84,7 +84,7 @@ libp2p-mplex = { version = "0.40.0", path = "muxers/mplex" }
 libp2p-muxer-test-harness = { path = "muxers/test-harness" }
 libp2p-noise = { version = "0.43.1", path = "transports/noise" }
 libp2p-perf = { version = "0.2.0", path = "protocols/perf" }
-libp2p-ping = { version = "0.43.0", path = "protocols/ping" }
+libp2p-ping = { version = "0.43.1", path = "protocols/ping" }
 libp2p-plaintext = { version = "0.40.0", path = "transports/plaintext" }
 libp2p-pnet = { version = "0.23.0", path = "transports/pnet" }
 libp2p-quic = { version = "0.9.2", path = "transports/quic" }
diff --git a/protocols/ping/CHANGELOG.md b/protocols/ping/CHANGELOG.md
index fd0c0824ef0..7b46cdc3626 100644
--- a/protocols/ping/CHANGELOG.md
+++ b/protocols/ping/CHANGELOG.md
@@ -1,3 +1,11 @@
+## 0.43.1 - unreleased
+
+- Honor ping interval in case of errors.
+  Previously, we would immediately open another ping stream if the current one failed.
+  See [PR 4423].
+
+[PR 4423]: https://github.com/libp2p/rust-libp2p/pull/4423
+
 ## 0.43.0 
 
 - Raise MSRV to 1.65.
diff --git a/protocols/ping/Cargo.toml b/protocols/ping/Cargo.toml
index f66222efff7..29cf5985b76 100644
--- a/protocols/ping/Cargo.toml
+++ b/protocols/ping/Cargo.toml
@@ -3,7 +3,7 @@ name = "libp2p-ping"
 edition = "2021"
 rust-version = { workspace = true }
 description = "Ping protocol for libp2p"
-version = "0.43.0"
+version = "0.43.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"
diff --git a/protocols/ping/src/handler.rs b/protocols/ping/src/handler.rs
index 0cf5c6e5f07..522663196e6 100644
--- a/protocols/ping/src/handler.rs
+++ b/protocols/ping/src/handler.rs
@@ -303,6 +303,7 @@ impl ConnectionHandler for Handler {
                         return Poll::Ready(ConnectionHandlerEvent::NotifyBehaviour(Ok(rtt)));
                     }
                     Poll::Ready(Err(e)) => {
+                        self.interval.reset(self.config.interval);
                         self.pending_errors.push_front(e);
                     }
                 },
@@ -321,13 +322,16 @@ impl ConnectionHandler for Handler {
                     self.outbound = Some(OutboundState::OpenStream);
                     break;
                 }
-                None => {
-                    self.outbound = Some(OutboundState::OpenStream);
-                    let protocol = SubstreamProtocol::new(ReadyUpgrade::new(PROTOCOL_NAME), ());
-                    return Poll::Ready(ConnectionHandlerEvent::OutboundSubstreamRequest {
-                        protocol,
-                    });
-                }
+                None => match self.interval.poll_unpin(cx) {
+                    Poll::Pending => break,
+                    Poll::Ready(()) => {
+                        self.outbound = Some(OutboundState::OpenStream);
+                        let protocol = SubstreamProtocol::new(ReadyUpgrade::new(PROTOCOL_NAME), ());
+                        return Poll::Ready(ConnectionHandlerEvent::OutboundSubstreamRequest {
+                            protocol,
+                        });
+                    }
+                },
             }
         }
 
diff --git a/protocols/ping/src/protocol.rs b/protocols/ping/src/protocol.rs
index 59e583a8b3b..28549e1c198 100644
--- a/protocols/ping/src/protocol.rs
+++ b/protocols/ping/src/protocol.rs
@@ -35,8 +35,7 @@ pub const PROTOCOL_NAME: StreamProtocol = StreamProtocol::new("/ipfs/ping/1.0.0"
 ///
 /// At most a single inbound and outbound substream is kept open at
 /// any time. In case of a ping timeout or another error on a substream, the
-/// substream is dropped. If a configurable number of consecutive
-/// outbound pings fail, the connection is closed.
+/// substream is dropped.
 ///
 /// Successful pings report the round-trip time.
 ///