Fix Socket remoteAddress obtaining on Win32 dart-lang#51778

Author: slonm

runtime/bin/eventhandler_win.cc

@@ -455,6 +455,16 @@ bool ListenSocket::LoadAcceptEx() {
   return (status != SOCKET_ERROR);
 }
 
+bool ListenSocket::LoadGetAcceptExSockaddrs() {
+  // Load the LoadGetAcceptExSockaddrs function into memory using WSAIoctl.
+  GUID guid_load_accept_ex_sockaddrs = WSAID_GETACCEPTEXSOCKADDRS;
+  DWORD bytes;
+  int status = WSAIoctl(socket(), SIO_GET_EXTENSION_FUNCTION_POINTER,
+                        &guid_load_accept_ex_sockaddrs, sizeof(guid_load_accept_ex_sockaddrs), &GetAcceptExSockaddrs_,
+                        sizeof(GetAcceptExSockaddrs_), &bytes, NULL, NULL);
+  return (status != SOCKET_ERROR);
+}
+
 bool ListenSocket::IssueAccept() {
   MonitorLocker ml(&monitor_);
 
@@ -498,8 +508,21 @@ void ListenSocket::AcceptComplete(OverlappedBuffer* buffer,
     int rc = setsockopt(buffer->client(), SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
                         reinterpret_cast<char*>(&s), sizeof(s));
     if (rc == NO_ERROR) {
+      LPSOCKADDR local_addr = 0;
+      int local_addr_length = 0;
+      LPSOCKADDR remote_addr = 0;
+      int remote_addr_length = 0;
+      static const int kAcceptExAddressAdditionalBytes = 16;
+      static const int kAcceptExAddressStorageSize =
+          sizeof(SOCKADDR_STORAGE) + kAcceptExAddressAdditionalBytes;
+      GetAcceptExSockaddrs_(buffer->GetBufferStart(), 0, kAcceptExAddressStorageSize,
+          kAcceptExAddressStorageSize, &local_addr, &local_addr_length,
+          &remote_addr, &remote_addr_length);
+      RawAddr* remote_addr_ = new RawAddr;
+      memcpy(remote_addr_, remote_addr, remote_addr_length);
+
       // Insert the accepted socket into the list.
-      ClientSocket* client_socket = new ClientSocket(buffer->client());
+      ClientSocket* client_socket = new ClientSocket(buffer->client(), remote_addr_);
       client_socket->mark_connected();
       client_socket->CreateCompletionPort(completion_port);
       if (accepted_head_ == NULL) {
@@ -559,6 +582,7 @@ void ListenSocket::DoClose() {
   // before EnsureInitialized was called, we have to reset the AcceptEx_
   // function pointer.
   AcceptEx_ = NULL;
+  GetAcceptExSockaddrs_ = NULL;
 }
 
 bool ListenSocket::CanAccept() {
@@ -603,6 +627,9 @@ void ListenSocket::EnsureInitialized(
     CreateCompletionPort(event_handler_->completion_port());
     LoadAcceptEx();
   }
+  if (GetAcceptExSockaddrs_ == NULL) {
+    LoadGetAcceptExSockaddrs();
+  }
 }
 
 bool ListenSocket::IsClosed() {

runtime/bin/eventhandler_win.h

@@ -16,6 +16,7 @@
 #include "bin/builtin.h"
 #include "bin/reference_counting.h"
 #include "bin/thread.h"
+#include "bin/socket_base.h"
 
 namespace dart {
 namespace bin {
@@ -387,6 +388,7 @@ class ListenSocket : public DescriptorInfoMultipleMixin<SocketHandle> {
   explicit ListenSocket(intptr_t s)
       : DescriptorInfoMultipleMixin(s, true),
         AcceptEx_(NULL),
+        GetAcceptExSockaddrs_(NULL),
         pending_accept_count_(0),
         accepted_head_(NULL),
         accepted_tail_(NULL),
@@ -419,8 +421,12 @@ class ListenSocket : public DescriptorInfoMultipleMixin<SocketHandle> {
  private:
   bool LoadAcceptEx();
 
+  bool LoadGetAcceptExSockaddrs();
+
   LPFN_ACCEPTEX AcceptEx_;
 
+  LPFN_GETACCEPTEXSOCKADDRS GetAcceptExSockaddrs_;
+
   // The number of asynchronous `IssueAccept` operations which haven't completed
   // yet.
   int pending_accept_count_;
@@ -440,12 +446,13 @@ class ListenSocket : public DescriptorInfoMultipleMixin<SocketHandle> {
 // Information on connected sockets.
 class ClientSocket : public DescriptorInfoSingleMixin<SocketHandle> {
  public:
-  explicit ClientSocket(intptr_t s)
+  explicit ClientSocket(intptr_t s, RawAddr* premote_addr = NULL)
       : DescriptorInfoSingleMixin(s, true),
         DisconnectEx_(NULL),
         next_(NULL),
         connected_(false),
-        closed_(false) {
+        closed_(false),
+        premote_addr_(premote_addr) {
     LoadDisconnectEx();
     type_ = kClientSocket;
   }
@@ -456,6 +463,7 @@ class ClientSocket : public DescriptorInfoSingleMixin<SocketHandle> {
     ASSERT(!HasPendingWrite());
     ASSERT(next_ == NULL);
     ASSERT(closed_ == true);
+    delete premote_addr_;
   }
 
   void Shutdown(int how);
@@ -480,6 +488,8 @@ class ClientSocket : public DescriptorInfoSingleMixin<SocketHandle> {
 
   void mark_closed() { closed_ = true; }
 
+  RawAddr* const get_remote_addr() const { return premote_addr_;}
+
 #if defined(DEBUG)
   static intptr_t disconnecting() { return disconnecting_; }
 #endif
@@ -491,6 +501,7 @@ class ClientSocket : public DescriptorInfoSingleMixin<SocketHandle> {
   ClientSocket* next_;
   bool connected_;
   bool closed_;
+  RawAddr* premote_addr_;
 
 #if defined(DEBUG)
   static intptr_t disconnecting_;

runtime/bin/socket_base_win.cc

@@ -181,10 +181,16 @@ intptr_t SocketBase::GetPort(intptr_t fd) {
 SocketAddress* SocketBase::GetRemotePeer(intptr_t fd, intptr_t* port) {
   ASSERT(reinterpret_cast<Handle*>(fd)->is_socket());
   SocketHandle* socket_handle = reinterpret_cast<SocketHandle*>(fd);
-  RawAddr raw;
-  socklen_t size = sizeof(raw);
-  if (getpeername(socket_handle->socket(), &raw.addr, &size)) {
-    return NULL;
+  RawAddr raw{};
+  RawAddr* praw;
+  if(socket_handle->is_client_socket() &&
+     (praw = reinterpret_cast<ClientSocket*>(fd)->get_remote_addr())) {
+    memcpy(&raw, praw, SocketAddress::GetAddrLength(*praw));    
+  } else {
+    socklen_t size = sizeof(raw);
+    if (getpeername(socket_handle->socket(), &raw.addr, &size)) {
+      return NULL;
+    }
   }
   *port = SocketAddress::GetAddrPort(raw);
   // Clear the port before calling WSAAddressToString as WSAAddressToString