From fd410061931b0a48283893ece1913c27c0082f68 Mon Sep 17 00:00:00 2001
From: David Cermak <cermak@espressif.com>
Date: Fri, 27 Jun 2025 12:37:52 +0200
Subject: [PATCH] fix(mosq): Fix misleading error when accepting connection

Closes https://github.com/espressif/esp-protocols/issues/807
---
 components/mosquitto/port/net__esp_tls.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/components/mosquitto/port/net__esp_tls.c b/components/mosquitto/port/net__esp_tls.c
index 078a47f9d..cbe771581 100644
--- a/components/mosquitto/port/net__esp_tls.c
+++ b/components/mosquitto/port/net__esp_tls.c
@@ -3,7 +3,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  *
- * SPDX-FileContributor: 2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileContributor: 2024-2025 Espressif Systems (Shanghai) CO LTD
  */
 
 /*
@@ -106,6 +106,9 @@ struct mosquitto *net__socket_accept(struct mosquitto__listener_sock *listensock
 
     new_sock = accept(listensock->sock, NULL, 0);
     if (new_sock == INVALID_SOCKET) {
+        if (errno == EAGAIN) {  // mosquitto tries to accept() in a loop until EAGAIN is returned
+            return NULL;
+        }
         log__printf(NULL, MOSQ_LOG_ERR,
                     "Unable to accept new connection, system socket count has been exceeded. Try increasing \"ulimit -n\" or equivalent.");
         return NULL;