[wpinet] Directly link to mDNS APIs on Windows (#8374)

These were added in Windows 10 1703. Technically Windows 10 in general
is out of support, but versions of Windows 10 older than that are _well_
out of support. And we do directly link to other APIs that are newer. So
no need to do the dynamic linking.

wpinet/src/main/native/windows/DynamicDns.cpp

@@ -1,41 +0,0 @@
-// Copyright (c) FIRST and other WPILib contributors.
-// Open Source Software; you can modify and/or share it under the terms of
-// the WPILib BSD license file in the root directory of this project.
-
-#include "DynamicDns.hpp"
-
-using namespace wpi::net;
-
-DynamicDns& DynamicDns::GetDynamicDns() {
-  static DynamicDns dns;
-  return dns;
-}
-
-DynamicDns::DynamicDns() {
-  HMODULE library = LoadLibraryW(L"dnsapi");
-
-  if (library == nullptr) {
-    return;
-  }
-
-  DnsServiceFreeInstancePtr = (DnsServiceFreeInstanceFunc)GetProcAddress(
-      library, "DnsServiceFreeInstance");
-  DnsServiceConstructInstancePtr =
-      (DnsServiceConstructInstanceFunc)GetProcAddress(
-          library, "DnsServiceConstructInstance");
-  DnsServiceRegisterPtr =
-      (DnsServiceRegisterFunc)GetProcAddress(library, "DnsServiceRegister");
-  DnsServiceDeRegisterPtr =
-      (DnsServiceDeRegisterFunc)GetProcAddress(library, "DnsServiceDeRegister");
-
-  CanDnsAnnounce = DnsServiceFreeInstancePtr &&
-                   DnsServiceConstructInstancePtr && DnsServiceRegisterPtr &&
-                   DnsServiceDeRegisterPtr;
-
-  DnsServiceBrowsePtr =
-      (DnsServiceBrowseFunc)GetProcAddress(library, "DnsServiceBrowse");
-  DnsServiceBrowseCancelPtr = (DnsServiceBrowseCancelFunc)GetProcAddress(
-      library, "DnsServiceBrowseCancel");
-
-  CanDnsResolve = DnsServiceBrowsePtr && DnsServiceBrowseCancelPtr;
-}

wpinet/src/main/native/windows/DynamicDns.hpp

@@ -1,58 +0,0 @@
-// Copyright (c) FIRST and other WPILib contributors.
-// Open Source Software; you can modify and/or share it under the terms of
-// the WPILib BSD license file in the root directory of this project.
-
-#pragma once
-
-#ifndef UNICODE
-#define UNICODE
-#endif
-
-#include <windows.h>
-#include <windns.h>
-
-namespace wpi::net {
-class DynamicDns {
- public:
-  using DnsServiceFreeInstanceFunc =
-      VOID(WINAPI*)(_In_ PDNS_SERVICE_INSTANCE pInstance);
-
-  using DnsServiceConstructInstanceFunc = PDNS_SERVICE_INSTANCE(WINAPI*)(
-      _In_ PCWSTR pServiceName, _In_ PCWSTR pHostName,
-      _In_opt_ PIP4_ADDRESS pIp4, _In_opt_ PIP6_ADDRESS pIp6, _In_ WORD wPort,
-      _In_ WORD wPriority, _In_ WORD wWeight, _In_ DWORD dwPropertiesCount,
-      _In_reads_(dwPropertiesCount) PCWSTR* keys,
-      _In_reads_(dwPropertiesCount) PCWSTR* values);
-
-  using DnsServiceRegisterFunc =
-      DWORD(WINAPI*)(_In_ PDNS_SERVICE_REGISTER_REQUEST pRequest,
-                     _Inout_opt_ PDNS_SERVICE_CANCEL pCancel);
-
-  using DnsServiceDeRegisterFunc =
-      DWORD(WINAPI*)(_In_ PDNS_SERVICE_REGISTER_REQUEST pRequest,
-                     _Inout_opt_ PDNS_SERVICE_CANCEL pCancel);
-
-  using DnsServiceBrowseFunc =
-      DNS_STATUS(WINAPI*)(_In_ PDNS_SERVICE_BROWSE_REQUEST pRequest,
-                          _Inout_ PDNS_SERVICE_CANCEL pCancel);
-
-  using DnsServiceBrowseCancelFunc =
-      DNS_STATUS(WINAPI*)(_In_ PDNS_SERVICE_CANCEL pCancelHandle);
-
-  DnsServiceBrowseFunc DnsServiceBrowsePtr{nullptr};
-  DnsServiceBrowseCancelFunc DnsServiceBrowseCancelPtr{nullptr};
-
-  DnsServiceFreeInstanceFunc DnsServiceFreeInstancePtr{nullptr};
-  DnsServiceConstructInstanceFunc DnsServiceConstructInstancePtr{nullptr};
-  DnsServiceRegisterFunc DnsServiceRegisterPtr{nullptr};
-  DnsServiceDeRegisterFunc DnsServiceDeRegisterPtr{nullptr};
-
-  bool CanDnsAnnounce{false};
-  bool CanDnsResolve{false};
-
-  static DynamicDns& GetDynamicDns();
-
- private:
-  DynamicDns();
-};
-}  // namespace wpi::net

wpinet/src/main/native/windows/MulticastServiceAnnouncer.cpp

@@ -8,12 +8,14 @@
 
 #include "wpi/net/MulticastServiceAnnouncer.h"
 
+#include <Windows.h>
+#include <WinDNS.h>
+
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
-#include "DynamicDns.hpp"
 #include "wpi/net/hostname.hpp"
 #include "wpi/util/ConvertUTF.hpp"
 #include "wpi/util/SmallString.hpp"
@@ -23,7 +25,6 @@
 using namespace wpi::net;
 
 struct ImplBase {
-  wpi::net::DynamicDns& dynamicDns = wpi::net::DynamicDns::GetDynamicDns();
   PDNS_SERVICE_INSTANCE serviceInstance = nullptr;
   HANDLE event = nullptr;
 };
@@ -47,10 +48,6 @@ template <typename T>
 MulticastServiceAnnouncer::Impl::Impl(std::string_view serviceName,
                                       std::string_view serviceType, int port,
                                       std::span<const std::pair<T, T>> txt) {
-  if (!dynamicDns.CanDnsAnnounce) {
-    return;
-  }
-
   this->port = port;
 
   wpi::util::SmallVector<wchar_t, 128> wideStorage;
@@ -127,7 +124,7 @@ MulticastServiceAnnouncer::~MulticastServiceAnnouncer() noexcept {
 }
 
 bool MulticastServiceAnnouncer::HasImplementation() const {
-  return pImpl->dynamicDns.CanDnsAnnounce;
+  return true;
 }
 
 static void WINAPI DnsServiceRegisterCallback(DWORD /*Status*/,
@@ -145,15 +142,10 @@ void MulticastServiceAnnouncer::Start() {
     return;
   }
 
-  if (!pImpl->dynamicDns.CanDnsAnnounce) {
-    return;
-  }
-
-  PDNS_SERVICE_INSTANCE serviceInst =
-      pImpl->dynamicDns.DnsServiceConstructInstancePtr(
-          pImpl->serviceInstanceName.c_str(), pImpl->hostName.c_str(), nullptr,
-          nullptr, pImpl->port, 0, 0, static_cast<DWORD>(pImpl->keyPtrs.size()),
-          pImpl->keyPtrs.data(), pImpl->valuePtrs.data());
+  PDNS_SERVICE_INSTANCE serviceInst = DnsServiceConstructInstance(
+      pImpl->serviceInstanceName.c_str(), pImpl->hostName.c_str(), nullptr,
+      nullptr, pImpl->port, 0, 0, static_cast<DWORD>(pImpl->keyPtrs.size()),
+      pImpl->keyPtrs.data(), pImpl->valuePtrs.data());
   if (serviceInst == nullptr) {
     return;
   }
@@ -168,12 +160,11 @@ void MulticastServiceAnnouncer::Start() {
 
   pImpl->event = CreateEvent(NULL, true, false, NULL);
 
-  if (pImpl->dynamicDns.DnsServiceRegisterPtr(&registerRequest, nullptr) ==
-      DNS_REQUEST_PENDING) {
+  if (DnsServiceRegister(&registerRequest, nullptr) == DNS_REQUEST_PENDING) {
     WaitForSingleObject(pImpl->event, INFINITE);
   }
 
-  pImpl->dynamicDns.DnsServiceFreeInstancePtr(serviceInst);
+  DnsServiceFreeInstance(serviceInst);
   CloseHandle(pImpl->event);
   pImpl->event = nullptr;
 }
@@ -183,7 +174,7 @@ static void WINAPI DnsServiceDeRegisterCallback(
   ImplBase* impl = reinterpret_cast<ImplBase*>(pQueryContext);
 
   if (pInstance != nullptr) {
-    impl->dynamicDns.DnsServiceFreeInstancePtr(pInstance);
+    DnsServiceFreeInstance(pInstance);
     pInstance = nullptr;
   }
 
@@ -191,10 +182,6 @@ static void WINAPI DnsServiceDeRegisterCallback(
 }
 
 void MulticastServiceAnnouncer::Stop() {
-  if (!pImpl->dynamicDns.CanDnsAnnounce) {
-    return;
-  }
-
   if (pImpl->serviceInstance == nullptr) {
     return;
   }
@@ -208,12 +195,11 @@ void MulticastServiceAnnouncer::Stop() {
   registerRequest.pServiceInstance = pImpl->serviceInstance;
   registerRequest.InterfaceIndex = 0;
 
-  if (pImpl->dynamicDns.DnsServiceDeRegisterPtr(&registerRequest, nullptr) ==
-      DNS_REQUEST_PENDING) {
+  if (DnsServiceDeRegister(&registerRequest, nullptr) == DNS_REQUEST_PENDING) {
     WaitForSingleObject(pImpl->event, INFINITE);
   }
 
-  pImpl->dynamicDns.DnsServiceFreeInstancePtr(pImpl->serviceInstance);
+  DnsServiceFreeInstance(pImpl->serviceInstance);
   pImpl->serviceInstance = nullptr;
   CloseHandle(pImpl->event);
   pImpl->event = nullptr;

wpinet/src/main/native/windows/MulticastServiceResolver.cpp

@@ -8,11 +8,13 @@
 
 #include "wpi/net/MulticastServiceResolver.h"
 
+#include <Windows.h>
+#include <WinDNS.h>
+
 #include <memory>
 #include <string>
 #include <utility>
 
-#include "DynamicDns.hpp"
 #include "wpi/util/ConvertUTF.hpp"
 #include "wpi/util/SmallString.hpp"
 #include "wpi/util/SmallVector.hpp"
@@ -23,7 +25,6 @@
 using namespace wpi::net;
 
 struct MulticastServiceResolver::Impl {
-  wpi::net::DynamicDns& dynamicDns = wpi::net::DynamicDns::GetDynamicDns();
   std::wstring serviceType;
   DNS_SERVICE_CANCEL serviceCancel{nullptr};
 
@@ -39,10 +40,6 @@ MulticastServiceResolver::MulticastServiceResolver(
   pImpl = std::make_unique<Impl>();
   pImpl->resolver = this;
 
-  if (!pImpl->dynamicDns.CanDnsResolve) {
-    return;
-  }
-
   wpi::util::SmallVector<wchar_t, 128> wideStorage;
 
   if (wpi::util::ends_with_lower(serviceType, ".local")) {
@@ -61,7 +58,7 @@ MulticastServiceResolver::~MulticastServiceResolver() noexcept {
 }
 
 bool MulticastServiceResolver::HasImplementation() const {
-  return pImpl->dynamicDns.CanDnsResolve;
+  return true;
 }
 
 bool MulticastServiceResolver::SetCopyCallback(
@@ -204,28 +201,20 @@ void MulticastServiceResolver::Start() {
     return;
   }
 
-  if (!pImpl->dynamicDns.CanDnsResolve) {
-    return;
-  }
-
   DNS_SERVICE_BROWSE_REQUEST request = {};
   request.InterfaceIndex = 0;
   request.pQueryContext = pImpl.get();
   request.QueryName = pImpl->serviceType.c_str();
   request.Version = 2;
   request.pBrowseCallbackV2 = DnsCompletion;
-  pImpl->dynamicDns.DnsServiceBrowsePtr(&request, &pImpl->serviceCancel);
+  DnsServiceBrowse(&request, &pImpl->serviceCancel);
 }
 
 void MulticastServiceResolver::Stop() {
-  if (!pImpl->dynamicDns.CanDnsResolve) {
-    return;
-  }
-
   if (pImpl->serviceCancel.reserved == nullptr) {
     return;
   }
 
-  pImpl->dynamicDns.DnsServiceBrowseCancelPtr(&pImpl->serviceCancel);
+  DnsServiceBrowseCancel(&pImpl->serviceCancel);
   pImpl->serviceCancel.reserved = nullptr;
 }