Allow server sockets to rebind to same port if there is nothing actively listening on that port.

net/socket/tcp_server_socket_win.cc

 // Copyright (c) 2012 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/socket/tcp_server_socket_win.h"
 
 #include <mstcpip.h>
 
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_errors.h"
@@ skipping 38 matching lines @@
     PLOG(ERROR) << "socket() returned an error";
     return MapSystemError(WSAGetLastError());
   }
 
   if (SetNonBlocking(socket_)) {
     int result = MapSystemError(WSAGetLastError());
     Close();
     return result;
   }
 
+  int result = SetSocketOptions();
+  if (result < 0) {
+    return result;
+  }
+
   SockaddrStorage storage;
   if (!address.ToSockAddr(storage.addr, &storage.addr_len))
     return ERR_INVALID_ARGUMENT;
 
-  int result = bind(socket_, storage.addr, storage.addr_len);
+  result = bind(socket_, storage.addr, storage.addr_len);
   if (result < 0) {
     PLOG(ERROR) << "bind() returned an error";
     result = MapSystemError(WSAGetLastError());
     Close();
     return result;
   }
 
   result = listen(socket_, backlog);
   if (result < 0) {
     PLOG(ERROR) << "listen() returned an error";
@@ skipping 99 matching lines @@
     int result = AcceptInternal(accept_socket_);
     if (result != ERR_IO_PENDING) {
       accept_socket_ = NULL;
       CompletionCallback callback = accept_callback_;
       accept_callback_.Reset();
       callback.Run(result);
     }
   }
 }
 
+void TCPServerSocketWin::AllowAddressReuse() {
+  DCHECK(CalledOnValidThread());
+  DCHECK_EQ(socket_, INVALID_SOCKET);
+  DCHECK_EQ(socket_event_, WSA_INVALID_EVENT);
+
+  socket_options_ |= SOCKET_OPTION_REUSE_ADDRESS;
+}
+
+int TCPServerSocketWin::SetSocketOptions() {
+  int true_value = 1;
+  if (socket_options_ & SOCKET_OPTION_REUSE_ADDRESS) {
+    int rv = setsockopt(socket_, SOL_SOCKET, SO_REUSEADDR, &true_value,
+                        sizeof(true_value));
+    if (rv < 0)
+      return MapSystemError(errno);
+  }
+  return OK;
+}
+
 }  // namespace net