From 37b10cbdec4bab7d577b504cfa781d9c4698aa83 Mon Sep 17 00:00:00 2001
From: xiehang <xiehang@espressif.com>
Date: Tue, 4 Aug 2020 19:57:12 +0800
Subject: [PATCH] arp: Return ERR_MEM if ARP queue is full

2.1.3-esp: 00585644 arp: Return ERR_MEM on ARP queue full
---
 contrib/examples/example_app/lwipopts.h |  1 +
 src/core/ipv4/etharp.c                  | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/contrib/examples/example_app/lwipopts.h b/contrib/examples/example_app/lwipopts.h
index 1c2837ab..994460f2 100644
--- a/contrib/examples/example_app/lwipopts.h
+++ b/contrib/examples/example_app/lwipopts.h
@@ -328,5 +328,6 @@ void lwip_example_app_platform_assert(const char *msg, int line, const char *fil
 #define ESP_LWIP_IGMP_TIMERS_ONDEMAND ESP_LWIP
 #define ESP_LWIP_MLD6_TIMERS_ONDEMAND ESP_LWIP
 #define ESP_DNS ESP_LWIP
+#define ESP_LWIP_ARP ESP_LWIP
 
 #endif /* LWIP_LWIPOPTS_H */
diff --git a/src/core/ipv4/etharp.c b/src/core/ipv4/etharp.c
index 3092dc94..367b7c13 100644
--- a/src/core/ipv4/etharp.c
+++ b/src/core/ipv4/etharp.c
@@ -1038,12 +1038,12 @@ etharp_query(struct netif *netif, const ip4_addr_t *ipaddr, struct pbuf *q)
       /* allocate a new arp queue entry */
       new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE);
       if (new_entry != NULL) {
+        struct etharp_q_entry *r;
         unsigned int qlen = 0;
         new_entry->next = NULL;
         new_entry->p = p;
         if (arp_table[i].q != NULL) {
           /* queue was already existent, append the new entry to the end */
-          struct etharp_q_entry *r;
           r = arp_table[i].q;
           qlen++;
           while (r->next != NULL) {
@@ -1057,11 +1057,19 @@ etharp_query(struct netif *netif, const ip4_addr_t *ipaddr, struct pbuf *q)
         }
 #if ARP_QUEUE_LEN
         if (qlen >= ARP_QUEUE_LEN) {
+#if ESP_LWIP_ARP 
+          r->next = NULL;
+          pbuf_free(new_entry->p);
+          memp_free(MEMP_ARP_QUEUE, new_entry);
+          LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue the packet %p (queue is full)\n", (void *)q));
+          return ERR_MEM;
+#else
           struct etharp_q_entry *old;
           old = arp_table[i].q;
           arp_table[i].q = arp_table[i].q->next;
           pbuf_free(old->p);
           memp_free(MEMP_ARP_QUEUE, old);
+#endif
         }
 #endif
         LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"U16_F"\n", (void *)q, i));