From cb958e5d695f2f5a2816d6b35e38fdabdf6a2042 Mon Sep 17 00:00:00 2001
From: Zhe Weng <wengzhe@xiaomi.com>
Date: Thu, 22 Dec 2022 11:35:02 +0800
Subject: [PATCH] net/nat: Clear entries when NAT will be disabled

Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
---
 net/nat/ipv4_nat.c       | 14 +++++++++++++-
 net/nat/ipv4_nat_entry.c | 35 +++++++++++++++++++++++++++++++++++
 net/nat/nat.h            | 17 +++++++++++++++++
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/net/nat/ipv4_nat.c b/net/nat/ipv4_nat.c
index 93709b705f..8f615f9f8c 100644
--- a/net/nat/ipv4_nat.c
+++ b/net/nat/ipv4_nat.c
@@ -687,13 +687,18 @@ ipv4_nat_outbound_internal(FAR struct net_driver_s *dev,
 
 int ipv4_nat_enable(FAR struct net_driver_s *dev)
 {
+  net_lock();
+
   if (IFF_IS_NAT(dev->d_flags))
     {
       nwarn("WARNING: NAT was already enabled for %s!\n", dev->d_ifname);
+      net_unlock();
       return -EEXIST;
     }
 
   IFF_SET_NAT(dev->d_flags);
+
+  net_unlock();
   return OK;
 }
 
@@ -714,15 +719,22 @@ int ipv4_nat_enable(FAR struct net_driver_s *dev)
 
 int ipv4_nat_disable(FAR struct net_driver_s *dev)
 {
+  net_lock();
+
   if (!IFF_IS_NAT(dev->d_flags))
     {
       nwarn("WARNING: NAT was not enabled for %s!\n", dev->d_ifname);
+      net_unlock();
       return -ENODEV;
     }
 
-  /* TODO: Clear entries related to dev. */
+  /* Clear entries related to dev. */
+
+  ipv4_nat_entry_clear(dev);
 
   IFF_CLR_NAT(dev->d_flags);
+
+  net_unlock();
   return OK;
 }
 
diff --git a/net/nat/ipv4_nat_entry.c b/net/nat/ipv4_nat_entry.c
index e9e8e5e484..fa106161b6 100644
--- a/net/nat/ipv4_nat_entry.c
+++ b/net/nat/ipv4_nat_entry.c
@@ -410,6 +410,41 @@ static void ipv4_nat_reclaim_entry(int32_t current_time)
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: ipv4_nat_entry_clear
+ *
+ * Description:
+ *   Clear all entries related to dev. Called when NAT will be disabled on
+ *   any device.
+ *
+ * Input Parameters:
+ *   dev        - The device on which NAT entries will be cleared.
+ *
+ * Assumptions:
+ *   NAT is initialized.
+ *
+ ****************************************************************************/
+
+void ipv4_nat_entry_clear(FAR struct net_driver_s *dev)
+{
+  FAR hash_node_t *p;
+  FAR hash_node_t *tmp;
+  int i;
+
+  ninfo("INFO: Clearing all NAT entries for %s\n", dev->d_ifname);
+
+  hashtable_for_every_safe(g_table_inbound, p, tmp, i)
+    {
+      FAR struct ipv4_nat_entry *entry =
+        container_of(p, struct ipv4_nat_entry, hash_inbound);
+
+      if (net_ipv4addr_cmp(entry->external_ip, dev->d_ipaddr))
+        {
+          ipv4_nat_entry_delete(entry);
+        }
+    }
+}
+
 /****************************************************************************
  * Name: ipv4_nat_inbound_entry_find
  *
diff --git a/net/nat/nat.h b/net/nat/nat.h
index ffedf5c1dc..4c70ceeb95 100644
--- a/net/nat/nat.h
+++ b/net/nat/nat.h
@@ -176,6 +176,23 @@ int ipv4_nat_outbound(FAR struct net_driver_s *dev,
 
 bool ipv4_nat_port_inuse(uint8_t protocol, in_addr_t ip, uint16_t port);
 
+/****************************************************************************
+ * Name: ipv4_nat_entry_clear
+ *
+ * Description:
+ *   Clear all entries related to dev. Called when NAT will be disabled on
+ *   any device.
+ *
+ * Input Parameters:
+ *   dev        - The device on which NAT entries will be cleared.
+ *
+ * Assumptions:
+ *   NAT is initialized.
+ *
+ ****************************************************************************/
+
+void ipv4_nat_entry_clear(FAR struct net_driver_s *dev);
+
 /****************************************************************************
  * Name: ipv4_nat_inbound_entry_find
  *