From 1e7fc9c115907c4813f9c4eae3e251c5572f92e3 Mon Sep 17 00:00:00 2001
From: leon <leon.yu@rootglobal.net>
Date: Mon, 8 Dec 2025 11:05:16 +0800
Subject: [PATCH] feat: auto-drop KCP packets on readbuf overflow

---
 event/kcp/hkcp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/event/kcp/hkcp.c b/event/kcp/hkcp.c
index 229594a5a..f771c67f1 100644
--- a/event/kcp/hkcp.c
+++ b/event/kcp/hkcp.c
@@ -141,6 +141,11 @@ int hio_read_kcp (hio_t* io, void* buf, int readbytes) {
     while (1) {
         int nrecv = ikcp_recv(kcp->ikcp, kcp->readbuf.base, kcp->readbuf.len);
         // printf("ikcp_recv nrecv=%d\n", nrecv);
+        if (nrecv == -3) { // drop packet when larger than readbuf.len
+            int peeksize = ikcp_peeksize(kcp->ikcp);
+            ikcp_recv(kcp->ikcp, NULL, peeksize);
+            nrecv = 0;
+        }
         if (nrecv < 0) break;
         hio_read_cb(io, kcp->readbuf.base, nrecv);
         ret += nrecv;