From 5a82d90e4df891d06dfb649d7674aa70a019bea5 Mon Sep 17 00:00:00 2001
From: Jiacheng Guo <gjc@google.com>
Date: Sun, 22 Mar 2020 06:40:14 +0800
Subject: [PATCH] [netif] enhance return value of adding external addresses
 (#4693)

This commit changes the return value of subscribing a pre-defined
address when it's already subscribed. Now returns OT_ERROR_ALREADY
instead of OT_ERROR_INVALID_ARGS.
---
 src/core/net/netif.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/core/net/netif.cpp b/src/core/net/netif.cpp
index 9f6633ee7..b72ac1a06 100644
--- a/src/core/net/netif.cpp
+++ b/src/core/net/netif.cpp
@@ -363,6 +363,8 @@ otError Netif::SubscribeExternalMulticast(const Address &aAddress)
     NetifMulticastAddress &linkLocalAllRoutersAddress = static_cast<NetifMulticastAddress &>(
         const_cast<otNetifMulticastAddress &>(kLinkLocalAllRoutersMulticastAddress));
 
+    VerifyOrExit(!IsMulticastSubscribed(aAddress), error = OT_ERROR_ALREADY);
+
     // Check that the address is not one of the fixed addresses:
     // LinkLocalAllRouters -> RealmLocalAllRouters -> LinkLocalAllNodes
     // -> RealmLocalAllNodes -> RealmLocalAllMpl.
@@ -372,8 +374,6 @@ otError Netif::SubscribeExternalMulticast(const Address &aAddress)
         VerifyOrExit(cur->GetAddress() != aAddress, error = OT_ERROR_INVALID_ARGS);
     }
 
-    VerifyOrExit(!IsMulticastSubscribed(aAddress), error = OT_ERROR_ALREADY);
-
     for (entry = &mExtMulticastAddresses[0]; entry < OT_ARRAY_END(mExtMulticastAddresses); entry++)
     {
         if (!entry->IsInUse())
@@ -482,14 +482,12 @@ otError Netif::AddExternalUnicastAddress(const NetifUnicastAddress &aAddress)
     otError              error = OT_ERROR_NONE;
     NetifUnicastAddress *entry;
 
-    VerifyOrExit(!aAddress.GetAddress().IsLinkLocal(), error = OT_ERROR_INVALID_ARGS);
-
     for (entry = mUnicastAddresses.GetHead(); entry; entry = entry->GetNext())
     {
         if (entry->GetAddress() == aAddress.GetAddress())
         {
             VerifyOrExit((entry >= &mExtUnicastAddresses[0]) && (entry < OT_ARRAY_END(mExtUnicastAddresses)),
-                         error = OT_ERROR_INVALID_ARGS);
+                         error = OT_ERROR_ALREADY);
 
             entry->mPrefixLength = aAddress.mPrefixLength;
             entry->mPreferred    = aAddress.mPreferred;
@@ -498,6 +496,8 @@ otError Netif::AddExternalUnicastAddress(const NetifUnicastAddress &aAddress)
         }
     }
 
+    VerifyOrExit(!aAddress.GetAddress().IsLinkLocal(), error = OT_ERROR_INVALID_ARGS);
+
     for (entry = &mExtUnicastAddresses[0]; entry < OT_ARRAY_END(mExtUnicastAddresses); entry++)
     {
         if (!entry->IsInUse())