From bc747dce0947011b5963462e70c5403022853a04 Mon Sep 17 00:00:00 2001
From: jarlamsa <jarno.lamsa@arm.com>
Date: Thu, 1 Apr 2021 13:22:07 +0300
Subject: [PATCH] Check for duplicate status callbacks before adding to the
 list

Duplicate status callbacks don't bring any value and can cause
memory leaks if caller calls for this function multiple times with
same status_cb. Also remove all the instances of the status_cb when
removing event listener.
---
 connectivity/netsocket/source/NetworkInterface.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/connectivity/netsocket/source/NetworkInterface.cpp b/connectivity/netsocket/source/NetworkInterface.cpp
index 3dcd4b33fee..3b2932ff8fa 100644
--- a/connectivity/netsocket/source/NetworkInterface.cpp
+++ b/connectivity/netsocket/source/NetworkInterface.cpp
@@ -145,6 +145,13 @@ static void call_all_event_listeners(NetworkInterface *iface, nsapi_event_t even
 void NetworkInterface::add_event_listener(mbed::Callback<void(nsapi_event_t, intptr_t)> status_cb)
 {
     iface_eventlist_t *event_list = get_interface_event_list_head();
+#if MBED_CONF_PLATFORM_CALLBACK_COMPARABLE
+    ns_list_foreach_safe(iface_eventlist_entry_t, entry, event_list) {
+        if (entry->status_cb == status_cb && entry->iface == this) {
+            return;
+        }
+    }
+#endif
     iface_eventlist_entry_t *entry = new iface_eventlist_entry_t;
     entry->iface = this;
     entry->status_cb = status_cb;
@@ -160,7 +167,6 @@ void NetworkInterface::remove_event_listener(mbed::Callback<void(nsapi_event_t,
         if (entry->status_cb == status_cb && entry->iface == this) {
             ns_list_remove(event_list, entry);
             delete entry;
-            return;
         }
     }
 }