Allow p2p UDP packages to set DSCP

net/udp/udp_socket_libevent.h

Index: net/udp/udp_socket_libevent.h
diff --git a/net/udp/udp_socket_libevent.h b/net/udp/udp_socket_libevent.h
index 8f68a9b57a90695a87101eca856448198daedffb..69bd1c6541adb265b8612b4d62f3be0a8b0df7c7 100644
--- a/net/udp/udp_socket_libevent.h
+++ b/net/udp/udp_socket_libevent.h
@@ -21,7 +21,7 @@ namespace net {
 
 class NET_EXPORT UDPSocketLibevent : public base::NonThreadSafe {
  public:
-  UDPSocketLibevent(DatagramSocket::BindType bind_type,
+ UDPSocketLibevent(DatagramSocket::BindType bind_type,
                     const RandIntCallback& rand_int_cb,
                     net::NetLog* net_log,
                     const net::NetLog::Source& source);
@@ -151,6 +151,15 @@ class NET_EXPORT UDPSocketLibevent : public base::NonThreadSafe {
   // other applications on the same host. See MSDN: http://goo.gl/6vqbj
   int SetMulticastLoopbackMode(bool loopback);
 
+  // Set the differentiated services flags on outgoing packets. May not
+  // do anything on some platforms.
+  // Some useful values:
+  //  46 (Expedited Forwarding) for telephony
+  //  34 (AF4) for interactive multimedia
+  //  26 (AF3) multimedia streaming
+  //  10 (AF1) bulk transfers
+  int SetToS(int dscp);

[Alpha Left Google, 2013/08/07 00:45:16]

Should we provide a enum include file that lists all the QoS values instead of
just an int.

[hubbe, 2013/08/07 17:20:35]

Done.

+
  private:
   static const int kInvalidSocket = -1;
 
@@ -233,6 +242,9 @@ class NET_EXPORT UDPSocketLibevent : public base::NonThreadSafe {
   // options that should be applied to |socket_| before Bind().
   int socket_options_;
 
+  // Differentiated Services Code Point.
+  int dscp_;
+
   // Multicast socket options cached for SetSocketOption.
   // Cannot be used after Bind().
   int multicast_time_to_live_;