core: add free function to enumerate network interfaces.

Change-Id: Icd89662afe9e1295cd18a615970c5b4299529b38
Refs: #1306
diff --git a/daemon/core/network-interface.hpp b/daemon/core/network-interface.hpp
new file mode 100644
index 0000000..d02171a
--- /dev/null
+++ b/daemon/core/network-interface.hpp
@@ -0,0 +1,60 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (C) 2014 Named Data Networking Project
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NFD_CORE_NETWORK_INTERFACE_HPP
+#define NFD_CORE_NETWORK_INTERFACE_HPP
+
+#include "common.hpp"
+#include "face/ethernet.hpp"
+
+#include <net/if.h>
+
+namespace nfd {
+
+class NetworkInterfaceInfo
+{
+public:
+  int index;
+  std::string name;
+  ethernet::Address etherAddress;
+  std::vector<boost::asio::ip::address_v4> ipv4Addresses;
+  std::vector<boost::asio::ip::address_v6> ipv6Addresses;
+  unsigned int flags;
+
+  bool
+  isLoopback() const;
+
+  bool
+  isMulticastCapable() const;
+
+  bool
+  isUp() const;
+};
+
+inline bool
+NetworkInterfaceInfo::isLoopback() const
+{
+  return (flags & IFF_LOOPBACK) != 0;
+}
+
+inline bool
+NetworkInterfaceInfo::isMulticastCapable() const
+{
+  return (flags & IFF_MULTICAST) != 0;
+}
+
+inline bool
+NetworkInterfaceInfo::isUp() const
+{
+  return (flags & IFF_UP) != 0;
+}
+
+std::list< shared_ptr<NetworkInterfaceInfo> >
+listNetworkInterfaces();
+
+} // namespace nfd
+
+#endif // NFD_CORE_NETWORK_INTERFACE_HPP