From a4d910b347319b50b2a78261b72e96aea3cf81c1 Mon Sep 17 00:00:00 2001
From: zhangyanjiao <zhangyanjiao@espressif.com>
Date: Thu, 19 Jul 2018 18:13:13 +0800
Subject: [PATCH] Release DHCP structure memory when netif is down

---
 src/core/netif.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/core/netif.c b/src/core/netif.c
index de10eec4..e9a7036d 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -429,6 +429,18 @@ netif_remove(struct netif *netif)
     netif_set_down(netif);
   }
 
+#if ESP_LWIP
+#if LWIP_DHCP
+  /* netif not under DHCP control by default */
+  struct dhcp *dhcp;
+  dhcp = netif_dhcp_data(netif);
+  if (dhcp) {
+    free(dhcp);
+    dhcp = NULL;
+  }
+#endif /* LWIP_DHCP */
+#endif
+
   mib2_remove_ip4(netif);
 
   /* this netif is default? */