If an idle socket has received data unexpectedly, we...

net/base/tcp_client_socket_win.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/tcp_client_socket.h"
 
 #include "base/memory_debug.h"
 #include "base/string_util.h"
 #include "base/trace_event.h"
 #include "net/base/net_errors.h"
@@ skipping 139 matching lines @@
   char c;
   int rv = recv(socket_, &c, 1, MSG_PEEK);
   if (rv == 0)
     return false;
   if (rv == SOCKET_ERROR && WSAGetLastError() != WSAEWOULDBLOCK)
     return false;
 
   return true;
 }
 
+bool TCPClientSocket::IsConnectedAndIdle() const {
+  if (socket_ == INVALID_SOCKET || wait_state_ == WAITING_CONNECT)
+    return false;
+
+  // Check if connection is alive and we haven't received any data
+  // unexpectedly.
+  char c;
+  int rv = recv(socket_, &c, 1, MSG_PEEK);
+  if (rv >= 0)
+    return false;
+  if (WSAGetLastError() != WSAEWOULDBLOCK)
+    return false;
+
+  return true;
+}
+
 int TCPClientSocket::Read(char* buf,
                           int buf_len,
                           CompletionCallback* callback) {
   DCHECK(socket_ != INVALID_SOCKET);
   DCHECK(wait_state_ == NOT_WAITING);
   DCHECK(!callback_);
 
   buffer_.len = buf_len;
   buffer_.buf = buf;
 
@@ skipping 193 matching lines @@
 void TCPClientSocket::WaitForAndResetEvent() {
   // TODO(wtc): Remove the CHECKs after enough testing.
   DWORD wait_rv = WaitForSingleObject(overlapped_.hEvent, INFINITE);
   CHECK(wait_rv == WAIT_OBJECT_0);
   BOOL ok = WSAResetEvent(overlapped_.hEvent);
   CHECK(ok);
 }
 
 }  // namespace net