Added broadcasting feature to UDP server sockets.

net/udp/udp_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/udp/udp_socket_win.h"
 
 #include <mstcpip.h>
 
 #include "base/callback.h"
 #include "base/eintr_wrapper.h"
@@ skipping 28 matching lines @@
 void UDPSocketWin::WriteDelegate::OnObjectSignaled(HANDLE object) {
   DCHECK_EQ(object, socket_->write_overlapped_.hEvent);
   socket_->DidCompleteWrite();
 }
 
 UDPSocketWin::UDPSocketWin(DatagramSocket::BindType bind_type,
                            const RandIntCallback& rand_int_cb,
                            net::NetLog* net_log,
                            const net::NetLog::Source& source)
     : socket_(INVALID_SOCKET),
+      allow_broadcast_(false),
       bind_type_(bind_type),
       rand_int_cb_(rand_int_cb),
       ALLOW_THIS_IN_INITIALIZER_LIST(read_delegate_(this)),
       ALLOW_THIS_IN_INITIALIZER_LIST(write_delegate_(this)),
       recv_from_address_(NULL),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_UDP_SOCKET)) {
   EnsureWinsockInit();
   net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
                       source.ToEventParametersCallback());
   memset(&read_overlapped_, 0, sizeof(read_overlapped_));
@@ skipping 163 matching lines @@
 
   remote_address_.reset(new IPEndPoint(address));
   return rv;
 }
 
 int UDPSocketWin::Bind(const IPEndPoint& address) {
   DCHECK(!is_connected());
   int rv = CreateSocket(address);
   if (rv < 0)
     return rv;
+  if (allow_broadcast_) {
+    rv = DoBroadcast();
+    if (rv < 0)
+      return rv;
+  }
   rv = DoBind(address);
   if (rv < 0)
     return rv;
   local_address_.reset();
   return rv;
 }
 
 int UDPSocketWin::CreateSocket(const IPEndPoint& address) {
   socket_ = WSASocket(address.GetFamily(), SOCK_DGRAM, IPPROTO_UDP, NULL, 0,
                       WSA_FLAG_OVERLAPPED);
@@ skipping 11 matching lines @@
 }
 
 bool UDPSocketWin::SetSendBufferSize(int32 size) {
   DCHECK(CalledOnValidThread());
   int rv = setsockopt(socket_, SOL_SOCKET, SO_SNDBUF,
                       reinterpret_cast<const char*>(&size), sizeof(size));
   DCHECK(!rv) << "Could not set socket send buffer size: " << errno;
   return rv == 0;
 }
 
+void UDPSocketWin::AllowBroadcast() {
+  DCHECK(CalledOnValidThread());
+  DCHECK(!is_connected());
+
+  allow_broadcast_ = true;
+}
+
 void UDPSocketWin::DoReadCallback(int rv) {
   DCHECK_NE(rv, ERR_IO_PENDING);
   DCHECK(!read_callback_.is_null());
 
   // since Run may result in Read being called, clear read_callback_ up front.
   CompletionCallback c = read_callback_;
   read_callback_.Reset();
   c.Run(rv);
 }
 
@@ skipping 151 matching lines @@
       int result = MapSystemError(os_error);
       LogWrite(result, NULL, NULL);
       return result;
     }
   }
 
   write_watcher_.StartWatching(write_overlapped_.hEvent, &write_delegate_);
   return ERR_IO_PENDING;
 }
 
+int UDPSocketWin::DoBroadcast() {
+  int true_value = 1;

[wtc, 2012/07/11 18:26:37]

It looks nicer to use the BOOL type here:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx

BOOL and int have the same size on Windows, so this doesn't
really matter.

The fourth argument to setsockopt is a const char* on Windows,
so the casts to const char* are necessary in this file.

[ygorshenin1, 2012/07/12 09:28:08]

Done.

+  int rv = setsockopt(socket_, SOL_SOCKET, SO_REUSEADDR,
+                      reinterpret_cast<const char*>(&true_value),
+                      sizeof(true_value));
+  if (rv < 0)
+    return MapSystemError(errno);
+  rv = setsockopt(socket_, SOL_SOCKET, SO_BROADCAST,
+                  reinterpret_cast<const char*>(&true_value),
+                  sizeof(true_value));
+  if (rv < 0)
+    return MapSystemError(errno);
+  return OK;
+}
+
 int UDPSocketWin::DoBind(const IPEndPoint& address) {
   SockaddrStorage storage;
   if (!address.ToSockAddr(storage.addr, &storage.addr_len))
     return ERR_UNEXPECTED;
   int rv = bind(socket_, storage.addr, storage.addr_len);
   return rv < 0 ? MapSystemError(WSAGetLastError()) : rv;
 }
 
 int UDPSocketWin::RandomBind(const IPEndPoint& address) {
   DCHECK(bind_type_ == DatagramSocket::RANDOM_BIND && !rand_int_cb_.is_null());
 
   // Construct IPAddressNumber of appropriate size (IPv4 or IPv6) of 0s.
   IPAddressNumber ip(address.address().size());
 
   for (int i = 0; i < kBindRetries; ++i) {
     int rv = DoBind(IPEndPoint(ip, rand_int_cb_.Run(kPortStart, kPortEnd)));
     if (rv == OK || rv != ERR_ADDRESS_IN_USE)
       return rv;
   }
   return DoBind(IPEndPoint(ip, 0));
 }
 
 bool UDPSocketWin::ReceiveAddressToIPEndpoint(IPEndPoint* address) const {
   const struct sockaddr* addr =
       reinterpret_cast<const struct sockaddr*>(&recv_addr_storage_);
   return address->FromSockAddr(addr, recv_addr_len_);
 }
 
 }  // namespace net