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,
+                    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))