From ed9f17e2bc4f97886819ca0ca91f57fd14f1d9a5 Mon Sep 17 00:00:00 2001
From: Abhik Roy <abhik.roy@espressif.com>
Date: Mon, 29 Apr 2024 20:07:33 +1000
Subject: [PATCH] fix(lwip): Fixed compilation error referencing undefined
 POSIX interface API

Closes https://github.com/espressif/esp-idf/issues/13577
---
 components/lwip/CMakeLists.txt  |  4 ++++
 components/lwip/port/if_index.c | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 components/lwip/port/if_index.c

diff --git a/components/lwip/CMakeLists.txt b/components/lwip/CMakeLists.txt
index edcf16878f..fc4dd60b7a 100644
--- a/components/lwip/CMakeLists.txt
+++ b/components/lwip/CMakeLists.txt
@@ -123,6 +123,10 @@ if(CONFIG_LWIP_PPP_SUPPORT)
         "lwip/src/netif/ppp/polarssl/md4.c"
         "lwip/src/netif/ppp/polarssl/md5.c"
         "lwip/src/netif/ppp/polarssl/sha1.c")
+
+    if(CONFIG_LWIP_NETIF_API)
+        list(APPEND srcs "port/if_index.c")
+    endif()
 endif()
 
 if(CONFIG_VFS_SUPPORT_IO)
diff --git a/components/lwip/port/if_index.c b/components/lwip/port/if_index.c
new file mode 100644
index 0000000000..d7dcf25e71
--- /dev/null
+++ b/components/lwip/port/if_index.c
@@ -0,0 +1,17 @@
+/*
+ * SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "lwip/if_api.h"
+
+unsigned int if_nametoindex(const char *ifname)
+{
+    return lwip_if_nametoindex(ifname);
+}
+
+char *if_indextoname(unsigned int ifindex, char *ifname)
+{
+    return lwip_if_indextoname(ifindex, ifname);
+}