From 571f843781604564d25945b6c1a15b795209d073 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damian=20Kr=C3=B3lik?=
 <66667989+Damian-Nordic@users.noreply.github.com>
Date: Fri, 12 Mar 2021 21:18:23 +0100
Subject: [PATCH] [mdns] Fix Resolver initialization (#5347)

ChipMdnsInit() call has recently been moved to
ServiceAdvertiser::Start, hence the function is never called
on the mDNS resolver side. Call the initialization function
when necessary.
---
 src/lib/mdns/Discovery_ImplPlatform.cpp | 34 ++++++++++++-------------
 src/lib/mdns/Discovery_ImplPlatform.h   |  2 ++
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/lib/mdns/Discovery_ImplPlatform.cpp b/src/lib/mdns/Discovery_ImplPlatform.cpp
index eb712430482f2f..1724591a1b03cb 100644
--- a/src/lib/mdns/Discovery_ImplPlatform.cpp
+++ b/src/lib/mdns/Discovery_ImplPlatform.cpp
@@ -57,24 +57,28 @@ constexpr uint64_t kUndefinedNodeId = 0;
 namespace chip {
 namespace Mdns {
 
-DiscoveryImplPlatform::DiscoveryImplPlatform()
-{
-    mCommissionInstanceName = GetRandU64();
-}
+DiscoveryImplPlatform DiscoveryImplPlatform::sManager;
 
-CHIP_ERROR DiscoveryImplPlatform::Start(Inet::InetLayer * inetLayer, uint16_t port)
+DiscoveryImplPlatform::DiscoveryImplPlatform() = default;
+
+CHIP_ERROR DiscoveryImplPlatform::Init()
 {
-    CHIP_ERROR error = CHIP_NO_ERROR;
     if (!mMdnsInitialized)
     {
         ReturnErrorOnFailure(ChipMdnsInit(HandleMdnsInit, HandleMdnsError, this));
-        mMdnsInitialized = true;
-    }
-    else
-    {
-        error = ChipMdnsStopPublish();
+        mCommissionInstanceName = GetRandU64();
+        mMdnsInitialized        = true;
     }
 
+    return CHIP_NO_ERROR;
+}
+
+CHIP_ERROR DiscoveryImplPlatform::Start(Inet::InetLayer * inetLayer, uint16_t port)
+{
+    ReturnErrorOnFailure(Init());
+
+    CHIP_ERROR error = ChipMdnsStopPublish();
+
     if (error != CHIP_NO_ERROR)
     {
         ChipLogError(Discovery, "Failed to initialize platform mdns: %s", ErrorStr(error));
@@ -280,6 +284,8 @@ CHIP_ERROR DiscoveryImplPlatform::SetResolverDelegate(ResolverDelegate * delegat
 
 CHIP_ERROR DiscoveryImplPlatform::ResolveNodeId(uint64_t nodeId, uint64_t fabricId, Inet::IPAddressType type)
 {
+    ReturnErrorOnFailure(Init());
+
     MdnsService service;
 
     snprintf(service.mName, sizeof(service.mName), "%" PRIX64 "-%" PRIX64, nodeId, fabricId);
@@ -357,12 +363,6 @@ void DiscoveryImplPlatform::HandleNodeIdResolve(void * context, MdnsService * re
 
 DiscoveryImplPlatform & DiscoveryImplPlatform::GetInstance()
 {
-    // TODO: Clean Mdns initialization order
-    // Previously sManager was a global object, but DiscoveryImplPlatform constructor calls
-    // platform-specific ChipMdnsInit() which for Linux initializes MdnsAvahi global object
-    // and that may lead to improper initialization, since the order in which global objects'
-    // constructors are called is undefined.
-    static DiscoveryImplPlatform sManager;
     return sManager;
 }
 
diff --git a/src/lib/mdns/Discovery_ImplPlatform.h b/src/lib/mdns/Discovery_ImplPlatform.h
index 1bc367f836b350..c05e227d5cb4ce 100644
--- a/src/lib/mdns/Discovery_ImplPlatform.h
+++ b/src/lib/mdns/Discovery_ImplPlatform.h
@@ -30,6 +30,8 @@ namespace Mdns {
 class DiscoveryImplPlatform : public ServiceAdvertiser, public Resolver
 {
 public:
+    CHIP_ERROR Init();
+
     CHIP_ERROR Start(Inet::InetLayer * inetLayer, uint16_t port) override;
 
     /// Advertises the CHIP node as an operational node