Added broadcasting feature to UDP server sockets.

net/udp/udp_socket_libevent.cc

Index: net/udp/udp_socket_libevent.cc
diff --git a/net/udp/udp_socket_libevent.cc b/net/udp/udp_socket_libevent.cc
index bb1cf91ede1fac18c855dca63eb4b12d701a9244..3782db3c24b5bcacd8ed01af2a39270357055d3d 100644
--- a/net/udp/udp_socket_libevent.cc
+++ b/net/udp/udp_socket_libevent.cc
@@ -41,6 +41,7 @@ UDPSocketLibevent::UDPSocketLibevent(
     net::NetLog* net_log,
     const net::NetLog::Source& source)
         : socket_(kInvalidSocket),
+          socket_options_(0),
           bind_type_(bind_type),
           rand_int_cb_(rand_int_cb),
           read_watcher_(this),
@@ -251,6 +252,9 @@ int UDPSocketLibevent::Bind(const IPEndPoint& address) {
   int rv = CreateSocket(address);
   if (rv < 0)
     return rv;
+  rv = SetSocketOptions();
+  if (rv < 0)
+    return rv;
   rv = DoBind(address);
   if (rv < 0)
     return rv;
@@ -274,6 +278,20 @@ bool UDPSocketLibevent::SetSendBufferSize(int32 size) {
   return rv == 0;
 }
 
+void UDPSocketLibevent::AllowAddressReuse() {
+  DCHECK(CalledOnValidThread());
+  DCHECK(!is_connected());
+
+  socket_options_ |= SOCKET_OPTION_REUSE_ADDRESS;
+}
+
+void UDPSocketLibevent::AllowBroadcast() {
+  DCHECK(CalledOnValidThread());
+  DCHECK(!is_connected());
+
+  socket_options_ |= SOCKET_OPTION_BROADCAST;
+}
+
 void UDPSocketLibevent::DoReadCallback(int rv) {
   DCHECK_NE(rv, ERR_IO_PENDING);
   DCHECK(!read_callback_.is_null());
@@ -430,6 +448,29 @@ int UDPSocketLibevent::InternalSendTo(IOBuffer* buf, int buf_len,
   return result;
 }
 
+int UDPSocketLibevent::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);
+#if defined(SO_REUSEPORT)
+    rv = setsockopt(socket_, SOL_SOCKET, SO_REUSEPORT, &true_value,

[Sergey Ulanov, 2012/09/12 19:13:10]

Why do we really need this option here? It seems like if we have it here then
AllowAddressReuse() will behave differently on Mac and Windows. Also I'm not
sure if implementation of SO_REUSEPORT is consistent between Linux and Mac -
e.g. Mac's man page mentions how this option changes behavior for broadcast
sockets, but Linux docs don't. If we need it on mac to receive broadcast
messages properly, then maybe enable it only when broadcast is enabled?

[ygorshenin1, 2012/09/13 18:29:16]

Thanks, Sergey, you're right. SO_REUSEPORT is used together with a
broadcasting/multicasting. Please, take a look at
http://codereview.chromium.org/10917235/.

On 2012/09/12 19:13:10, sergeyu wrote:

+                    sizeof(true_value));
+    if (rv < 0)
+      return MapSystemError(errno);
+#endif
+  }
+  if (socket_options_ & SOCKET_OPTION_BROADCAST) {
+    int rv = setsockopt(socket_, SOL_SOCKET, SO_BROADCAST, &true_value,
+                        sizeof(true_value));
+    if (rv < 0)
+      return MapSystemError(errno);
+  }
+  return OK;
+}
+
 int UDPSocketLibevent::DoBind(const IPEndPoint& address) {
   SockaddrStorage storage;
   if (!address.ToSockAddr(storage.addr, &storage.addr_len))