From 83edc19882a50d6004d3d9e1485d17d810691010 Mon Sep 17 00:00:00 2001
From: xiehang <xiehang@espressif.com>
Date: Mon, 30 Dec 2019 11:23:03 +0800
Subject: [PATCH] ip_frag: Drop IPv4 packets larger than MTU

Drop larger packets if ipv4-fragmentation is disabled

Ref IDF-4846
---
 src/core/ipv4/ip4.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/core/ipv4/ip4.c b/src/core/ipv4/ip4.c
index 0cf58903..ad428e22 100644
--- a/src/core/ipv4/ip4.c
+++ b/src/core/ipv4/ip4.c
@@ -1030,6 +1030,8 @@ ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *d
   if (netif->mtu && (p->tot_len > netif->mtu)) {
     return ip4_frag(p, netif, dest);
   }
+#else
+  LWIP_ERROR("ip4_output_if: Packet larger than MTU discarded", !(netif->mtu && p->tot_len > netif->mtu), return ERR_IF;);
 #endif /* IP_FRAG */
 
   LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));