[dnssd] implement otPlatDnssd APIs

This commit adds `DnssPlatform` module which implements OpenThread
platform APIs `otPlatDnssd` for registering and unregistering host,
service, and key items, and APIs for starting/stopping service
browsers, service resolvers, and address resolvers.

This commit also adds a new config `OTBR_DNSSD_PLAT` which enables the
new module and ensure its related OT core module are enabled (such as
advertising-proxy).

etc/cmake/options.cmake

@@ -98,6 +98,12 @@ if (OTBR_DNSSD_DISCOVERY_PROXY)
  target_compile_definitions(otbr-config INTERFACE OTBR_ENABLE_DNSSD_DISCOVERY_PROXY=1)
 endif()
 
+# When enabled the Advertising Proxy and Discovery proxy will be supported by OpenThread core
+option(OTBR_DNSSD_PLAT "Enable DNS-SD plat APIs for Advertising proxy and Discovery proxy in core" OFF)
+if (OTBR_DNSSD_PLAT)
+ target_compile_definitions(otbr-config INTERFACE OTBR_ENABLE_DNSSD_PLAT=1)
+endif()
+
 option(OTBR_UNSECURE_JOIN "Enable unsecure joining" OFF)
 if(OTBR_UNSECURE_JOIN)
  target_compile_definitions(otbr-config INTERFACE OTBR_ENABLE_UNSECURE_JOIN=1)

script/_otbr

@@ -73,6 +73,7 @@ otbr_install()
  "-DOTBR_DBUS=ON"
  "-DOTBR_DNSSD_DISCOVERY_PROXY=ON"
  "-DOTBR_SRP_ADVERTISING_PROXY=ON"
+ "-DOTBR_DNSSD_PLAT=OFF"
  "-DOTBR_INFRA_IF_NAME=${INFRA_IF_NAME}"
  "-DOTBR_MDNS=${OTBR_MDNS:=mDNSResponder}"
  # Force re-evaluation of version strings

src/agent/application.cpp

@@ -70,6 +70,9 @@ Application::Application(const std::string &aInterfaceName,
 #if OTBR_ENABLE_BACKBONE_ROUTER
  , mBackboneAgent(mNcp, aInterfaceName, mBackboneInterfaceName)
 #endif
+#if OTBR_ENABLE_DNSSD_PLAT
+ , mDnssdPlatform(mNcp, *mPublisher)
+#endif
 #if OTBR_ENABLE_SRP_ADVERTISING_PROXY
  , mAdvertisingProxy(mNcp, *mPublisher)
 #endif
@@ -109,6 +112,9 @@ void Application::Init(void)
 #if OTBR_ENABLE_BACKBONE_ROUTER
  mBackboneAgent.Init();
 #endif
+#if OTBR_ENABLE_DNSSD_PLAT
+ mDnssdPlatform.Start();
+#endif
 #if OTBR_ENABLE_SRP_ADVERTISING_PROXY
  mAdvertisingProxy.SetEnabled(true);
 #endif
@@ -131,6 +137,9 @@ void Application::Init(void)
 
 void Application::Deinit(void)
 {
+#if OTBR_ENABLE_DNSSD_PLAT
+ mDnssdPlatform.Stop();
+#endif
 #if OTBR_ENABLE_SRP_ADVERTISING_PROXY
  mAdvertisingProxy.SetEnabled(false);
 #endif
@@ -226,6 +235,9 @@ void Application::HandleMdnsState(Mdns::Publisher::State aState)
 {
  OTBR_UNUSED_VARIABLE(aState);
 
+#if OTBR_ENABLE_DNSSD_PLAT
+ mDnssdPlatform.HandleMdnsPublisherStateChange(aState);
+#endif
 #if OTBR_ENABLE_BORDER_AGENT
  mBorderAgent.HandleMdnsState(aState);
 #endif

src/agent/application.hpp

@@ -271,6 +271,9 @@ class Application : private NonCopyable
 #if OTBR_ENABLE_BACKBONE_ROUTER
  BackboneRouter::BackboneAgent mBackboneAgent;
 #endif
+#if OTBR_ENABLE_DNSSD_PLAT
+ DnssdPlatform mDnssdPlatform;
+#endif
 #if OTBR_ENABLE_SRP_ADVERTISING_PROXY
  AdvertisingProxy mAdvertisingProxy;
 #endif

src/border_agent/border_agent.hpp

@@ -47,6 +47,7 @@
 #include "backbone_router/backbone_agent.hpp"
 #include "common/code_utils.hpp"
 #include "common/mainloop.hpp"
+#include "mdns/dnssd_plat.hpp"
 #include "mdns/mdns.hpp"
 #include "ncp/ncp_openthread.hpp"
 #include "sdp_proxy/advertising_proxy.hpp"

src/mdns/CMakeLists.txt

@@ -30,6 +30,7 @@ if(OTBR_MDNS STREQUAL "avahi")
  add_library(otbr-mdns
  mdns.cpp
  mdns_avahi.cpp
+ dnssd_plat.cpp
  )
  target_compile_definitions(otbr-mdns PUBLIC
  OTBR_ENABLE_MDNS_AVAHI=1
@@ -48,6 +49,7 @@ if(OTBR_MDNS STREQUAL "mDNSResponder")
  add_library(otbr-mdns
  mdns.cpp
  mdns_mdnssd.cpp
+ dnssd_plat.cpp
  )
  target_compile_definitions(otbr-mdns PUBLIC
  OTBR_ENABLE_MDNS_MDNSSD=1