Added a helper function (SetIpInfoInCmsg) for WritePacket which fills in

net/tools/quic/quic_socket_utils.h

 // 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.
 //
 // Some socket related helper methods for quic.
 
 #ifndef NET_TOOLS_QUIC_QUIC_SOCKET_UTILS_H_
 #define NET_TOOLS_QUIC_QUIC_SOCKET_UTILS_H_
 
 #include <stddef.h>
@@ skipping 45 matching lines @@
                         IPEndPoint* peer_address);
 
   // Writes buf_len to the socket. If writing is successful, sets the result's
   // status to WRITE_STATUS_OK and sets bytes_written.  Otherwise sets the
   // result's status to WRITE_STATUS_BLOCKED or WRITE_STATUS_ERROR and sets
   // error_code to errno.
   static WriteResult WritePacket(int fd, const char* buffer, size_t buf_len,
                                  const IPAddressNumber& self_address,
                                  const IPEndPoint& peer_address);
 
+  // A helper for WritePacket which fills in the cmsg with the supplied self
+  // address.
+  static void SetIpInfoInCmsg(const IPAddressNumber& self_address,
+                              cmsghdr* cmsg);
+
  private:
   DISALLOW_COPY_AND_ASSIGN(QuicSocketUtils);
 };
 
 }  // namespace tools
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_SOCKET_UTILS_H_