From ad1350f0acee28f7458b4105d7af9eb6f30540f0 Mon Sep 17 00:00:00 2001
From: XiaXiaotian <xiaxiaotian@espressif.com>
Date: Thu, 12 Oct 2017 17:03:44 +0800
Subject: [PATCH] Release DHCP structure memory when netif is down.

---
 components/lwip/core/netif.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/components/lwip/core/netif.c b/components/lwip/core/netif.c
index f745f29ac..76e6f6132 100755
--- a/components/lwip/core/netif.c
+++ b/components/lwip/core/netif.c
@@ -369,6 +369,14 @@ netif_remove(struct netif *netif)
     netif_set_down(netif);
   }
 
+#if LWIP_DHCP
+  /* netif not under DHCP control by default */
+  if (netif->dhcp) {
+      free(netif->dhcp);
+      netif->dhcp = NULL;
+  }
+#endif /* LWIP_DHCP */
+
   mib2_remove_ip4(netif);
 
   /* this netif is default? */