From 34b0f2556d6dad057f9867518bd57d6e83787161 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Wed, 1 Feb 2023 21:09:46 +0000
Subject: [PATCH] Suggest a socket read buffer of 4KiB to limit message count

...and switch the same in `lightning-net-tokio`
---
 lightning-net-tokio/src/lib.rs   | 5 +++--
 lightning/src/ln/peer_handler.rs | 3 +++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/lightning-net-tokio/src/lib.rs b/lightning-net-tokio/src/lib.rs
index 9616e0db6..b259f77ef 100644
--- a/lightning-net-tokio/src/lib.rs
+++ b/lightning-net-tokio/src/lib.rs
@@ -176,8 +176,9 @@ impl Connection {
 		let (event_waker, event_receiver) = mpsc::channel(1);
 		tokio::spawn(Self::poll_event_process(peer_manager.clone(), event_receiver));
 
-		// 8KB is nice and big but also should never cause any issues with stack overflowing.
-		let mut buf = [0; 8192];
+		// 4KiB is nice and big without handling too many messages all at once, giving other peers
+		// a chance to do some work.
+		let mut buf = [0; 4096];
 
 		let mut our_descriptor = SocketDescriptor::new(us.clone());
 		// An enum describing why we did/are disconnecting:
diff --git a/lightning/src/ln/peer_handler.rs b/lightning/src/ln/peer_handler.rs
index cecf4332e..f24061726 100644
--- a/lightning/src/ln/peer_handler.rs
+++ b/lightning/src/ln/peer_handler.rs
@@ -1005,6 +1005,9 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 	/// [`send_data`] call on this descriptor has `resume_read` set (preventing DoS issues in the
 	/// send buffer).
 	///
+	/// In order to avoid processing too many messages at once per peer, `data` should be on the
+	/// order of 4KiB.
+	///
 	/// [`send_data`]: SocketDescriptor::send_data
 	/// [`process_events`]: PeerManager::process_events
 	pub fn read_event(&self, peer_descriptor: &mut Descriptor, data: &[u8]) -> Result<bool, PeerHandleError> {
-- 
2.39.5