[dnssd] Allow selecting DNS-SD implementation at runtime (#32829)

Add Resolver::SetInstance() and ServiceAdvertiser::SetInstance()
methods for dynamically changing the system-wide DNS-SD
implementation used by Matter.

Also, allow for building "minimal" and "platform" DNS-SD
implementations together.

Co-authored-by: Damian Krolik <damian.krolik@nordicsemi.no>

Author: kkasperczyk-no

config/nrfconnect/chip-module/CMakeLists.txt

@@ -140,6 +140,8 @@ matter_add_gn_arg_bool  ("chip_system_config_provide_statistics"  CONFIG_CHIP_ST
 matter_add_gn_arg_bool  ("chip_enable_icd_server"                 CONFIG_CHIP_ENABLE_ICD_SUPPORT)
 matter_add_gn_arg_bool  ("chip_enable_factory_data"               CONFIG_CHIP_FACTORY_DATA)
 matter_add_gn_arg_bool  ("chip_enable_read_client"                CONFIG_CHIP_ENABLE_READ_CLIENT)
+matter_add_gn_arg_bool  ("chip_mdns_minimal"                      CONFIG_WIFI_NRF700X)
+matter_add_gn_arg_bool  ("chip_mdns_platform"                     CONFIG_NET_L2_OPENTHREAD)
 
 if (CONFIG_CHIP_ENABLE_ICD_SUPPORT)
     matter_add_gn_arg_bool  ("chip_enable_icd_lit"                       CONFIG_CHIP_ICD_LIT_SUPPORT)
@@ -157,10 +159,10 @@ if (CONFIG_CHIP_ROTATING_DEVICE_ID)
     matter_add_gn_arg_bool("chip_enable_additional_data_advertising" TRUE)
 endif()
 
-if (CONFIG_NET_L2_OPENTHREAD)
-    matter_add_gn_arg_string("chip_mdns" "platform")
-elseif(CONFIG_WIFI_NRF700X)
+if(CONFIG_WIFI_NRF700X)
     matter_add_gn_arg_string("chip_mdns" "minimal")
+elseif (CONFIG_NET_L2_OPENTHREAD)
+    matter_add_gn_arg_string("chip_mdns" "platform")
 else()
     matter_add_gn_arg_string("chip_mdns" "none")
 endif()

src/lib/dnssd/Advertiser.cpp

@@ -0,0 +1,41 @@
+/*
+ *
+ *    Copyright (c) 2024 Project CHIP Authors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#include "Advertiser.h"
+
+namespace chip {
+namespace Dnssd {
+
+ServiceAdvertiser * ServiceAdvertiser::sInstance = nullptr;
+
+ServiceAdvertiser & ServiceAdvertiser::Instance()
+{
+    if (sInstance == nullptr)
+    {
+        sInstance = &GetDefaultAdvertiser();
+    }
+
+    return *sInstance;
+}
+
+void ServiceAdvertiser::SetInstance(ServiceAdvertiser & advertiser)
+{
+    sInstance = &advertiser;
+}
+
+} // namespace Dnssd
+} // namespace chip

src/lib/dnssd/Advertiser.h

@@ -375,9 +375,28 @@ class ServiceAdvertiser
      */
     virtual CHIP_ERROR UpdateCommissionableInstanceName() = 0;
 
-    /// Provides the system-wide implementation of the service advertiser
+    /**
+     * Returns the system-wide implementation of the service advertiser.
+     *
+     * The method returns a reference to the advertiser object configured by
+     * a user using the \c ServiceAdvertiser::SetInstance() method, or the
+     * default advertiser returned by the \c GetDefaultAdvertiser() function.
+     */
     static ServiceAdvertiser & Instance();
+
+    /**
+     * Sets the system-wide implementation of the service advertiser.
+     */
+    static void SetInstance(ServiceAdvertiser & advertiser);
+
+private:
+    static ServiceAdvertiser * sInstance;
 };
 
+/**
+ * Returns the default implementation of the service advertiser.
+ */
+extern ServiceAdvertiser & GetDefaultAdvertiser();
+
 } // namespace Dnssd
 } // namespace chip

src/lib/dnssd/Advertiser_ImplMinimalMdns.cpp

@@ -975,10 +975,14 @@ void AdvertiserMinMdns::AdvertiseRecords(BroadcastAdvertiseType type)
 AdvertiserMinMdns gAdvertiser;
 } // namespace
 
-ServiceAdvertiser & ServiceAdvertiser::Instance()
+#if CHIP_DNSSD_DEFAULT_MINIMAL
+
+ServiceAdvertiser & GetDefaultAdvertiser()
 {
     return gAdvertiser;
 }
 
+#endif // CHIP_DNSSD_DEFAULT_MINIMAL
+
 } // namespace Dnssd
 } // namespace chip

src/lib/dnssd/Advertiser_ImplNone.cpp

@@ -77,10 +77,14 @@ NoneAdvertiser gAdvertiser;
 
 } // namespace
 
-ServiceAdvertiser & ServiceAdvertiser::Instance()
+#if CHIP_DNSSD_DEFAULT_NONE
+
+ServiceAdvertiser & GetDefaultAdvertiser()
 {
     return gAdvertiser;
 }
 
+#endif // CHIP_DNSSD_DEFAULT_NONE
+
 } // namespace Dnssd
 } // namespace chip

src/lib/dnssd/BUILD.gn

@@ -68,22 +68,30 @@ static_library("dnssd") {
   ]
 
   sources = [
+    "Advertiser.cpp",
     "Advertiser.h",
     "IPAddressSorter.cpp",
     "IPAddressSorter.h",
+    "Resolver.cpp",
     "Resolver.h",
     "ResolverProxy.cpp",
     "ResolverProxy.h",
     "TxtFields.cpp",
     "TxtFields.h",
   ]
 
+  assert(
+      chip_mdns == "none" || chip_mdns == "minimal" || chip_mdns == "platform",
+      "Please select a valid value for chip_mdns")
+
   if (chip_mdns == "none") {
     sources += [
       "Advertiser_ImplNone.cpp",
       "Resolver_ImplNone.cpp",
     ]
-  } else if (chip_mdns == "minimal") {
+  }
+
+  if (chip_mdns_minimal) {
     sources += [
       "ActiveResolveAttempts.cpp",
       "ActiveResolveAttempts.h",
@@ -100,15 +108,25 @@ static_library("dnssd") {
       "${chip_root}/src/tracing",
       "${chip_root}/src/tracing:macros",
     ]
-  } else if (chip_mdns == "platform") {
+  }
+
+  if (chip_mdns_platform) {
     sources += [
       "Discovery_ImplPlatform.cpp",
       "Discovery_ImplPlatform.h",
     ]
     public_deps += [ "${chip_root}/src/platform" ]
-  } else {
-    assert(false, "Unknown Dnssd advertiser implementation.")
   }
 
+  _chip_dnssd_default_none = chip_mdns == "none"
+  _chip_dnssd_default_minimal = chip_mdns == "minimal"
+  _chip_dnssd_default_platform = chip_mdns == "platform"
+
+  defines = [
+    "CHIP_DNSSD_DEFAULT_NONE=${_chip_dnssd_default_none}",
+    "CHIP_DNSSD_DEFAULT_MINIMAL=${_chip_dnssd_default_minimal}",
+    "CHIP_DNSSD_DEFAULT_PLATFORM=${_chip_dnssd_default_platform}",
+  ]
+
   cflags = [ "-Wconversion" ]
 }

src/lib/dnssd/Discovery_ImplPlatform.cpp

@@ -769,15 +769,19 @@ DiscoveryImplPlatform & DiscoveryImplPlatform::GetInstance()
     return sManager.get();
 }
 
-ServiceAdvertiser & chip::Dnssd::ServiceAdvertiser::Instance()
+#if CHIP_DNSSD_DEFAULT_PLATFORM
+
+ServiceAdvertiser & GetDefaultAdvertiser()
 {
     return DiscoveryImplPlatform::GetInstance();
 }
 
-Resolver & chip::Dnssd::Resolver::Instance()
+Resolver & GetDefaultResolver()
 {
     return DiscoveryImplPlatform::GetInstance();
 }
 
+#endif // CHIP_DNSSD_DEFAULT_PLATFORM
+
 } // namespace Dnssd
 } // namespace chip

src/lib/dnssd/Resolver.cpp

@@ -0,0 +1,41 @@
+/*
+ *
+ *    Copyright (c) 2024 Project CHIP Authors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#include "Resolver.h"
+
+namespace chip {
+namespace Dnssd {
+
+Resolver * Resolver::sInstance = nullptr;
+
+Resolver & Resolver::Instance()
+{
+    if (sInstance == nullptr)
+    {
+        sInstance = &GetDefaultResolver();
+    }
+
+    return *sInstance;
+}
+
+void Resolver::SetInstance(Resolver & resolver)
+{
+    sInstance = &resolver;
+}
+
+} // namespace Dnssd
+} // namespace chip

src/lib/dnssd/Resolver.h

@@ -206,10 +206,27 @@ class Resolver
     virtual CHIP_ERROR ReconfirmRecord(const char * hostname, Inet::IPAddress address, Inet::InterfaceId interfaceId) = 0;
 
     /**
-     * Provides the system-wide implementation of the service resolver
+     * Returns the system-wide implementation of the service resolver.
+     *
+     * The method returns a reference to the resolver object configured by
+     * a user using the \c Resolver::SetInstance() method, or the default
+     * resolver returned by the \c GetDefaultResolver() function.
      */
     static Resolver & Instance();
+
+    /**
+     * Overrides the default implementation of the service resolver
+     */
+    static void SetInstance(Resolver & resolver);
+
+private:
+    static Resolver * sInstance;
 };
 
+/**
+ * Returns the default implementation of the service resolver.
+ */
+extern Resolver & GetDefaultResolver();
+
 } // namespace Dnssd
 } // namespace chip

src/lib/dnssd/Resolver_ImplMinimalMdns.cpp

@@ -758,10 +758,14 @@ MinMdnsResolver gResolver;
 
 } // namespace
 
-Resolver & chip::Dnssd::Resolver::Instance()
+#if CHIP_DNSSD_DEFAULT_MINIMAL
+
+Resolver & GetDefaultResolver()
 {
     return gResolver;
 }
 
+#endif // CHIP_DNSSD_DEFAULT_MINIMAL
+
 } // namespace Dnssd
 } // namespace chip

src/lib/dnssd/Resolver_ImplNone.cpp

@@ -59,10 +59,14 @@ NoneResolver gResolver;
 
 } // namespace
 
-Resolver & chip::Dnssd::Resolver::Instance()
+#if CHIP_DNSSD_DEFAULT_NONE
+
+Resolver & GetDefaultResolver()
 {
     return gResolver;
 }
 
+#endif // CHIP_DNSSD_DEFAULT_NONE
+
 } // namespace Dnssd
 } // namespace chip

src/platform/device.gni

@@ -126,6 +126,12 @@ if (chip_device_platform == "nxp" && chip_enable_openthread) {
   chip_mdns = "minimal"
 }
 
+declare_args() {
+  # Select DNS-SD components to build
+  chip_mdns_minimal = chip_mdns == "minimal"
+  chip_mdns_platform = chip_mdns == "platform"
+}
+
 _chip_device_layer = "none"
 if (chip_device_platform == "cc13x2_26x2") {
   _chip_device_layer = "cc13xx_26xx/cc13x2_26x2"

src/platform/nrfconnect/BUILD.gn

@@ -91,7 +91,7 @@ static_library("nrfconnect") {
       "ThreadStackManagerImpl.h",
     ]
 
-    if (chip_mdns == "platform") {
+    if (chip_mdns_platform) {
       sources += [
         "../OpenThread/DnssdImpl.cpp",
         "../OpenThread/OpenThreadDnssdImpl.cpp",