plugins/ip-faces: Implementing UdpFace and fixing bugs with TcpFace

Now UdpFace is fully working. Due to nature of UDP transmission, all
demultiplexing is happening inside IpFaceStack (with TCP, NS-3 is taking
care of that).

Bugfix: Map between IP addresses and Tcp/Udp faces was incorrectly
embedded as a static variable inside Udp/TcpFace implementation, causing
unexpected behavior.

Refs #1006 (http://redmine.named-data.net/)
diff --git a/examples/ndn-simple-udp.cc b/examples/ndn-simple-udp.cc
new file mode 100644
index 0000000..2fa093d
--- /dev/null
+++ b/examples/ndn-simple-udp.cc
@@ -0,0 +1,139 @@
+/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2012 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+// ndn-simple-tcp.cc
+#include "ns3/core-module.h"
+#include "ns3/network-module.h"
+#include "ns3/point-to-point-module.h"
+#include "ns3/internet-module.h"
+#include "ns3/ndnSIM-module.h"
+
+using namespace ns3;
+
+/**
+ * This scenario simulates a very simple network topology:
+ *
+ *
+ *      +----------+     1Mbps      +--------+     1Mbps      +----------+
+ *      | consumer | <------------> | router | <------------> | producer |
+ *      +----------+         10ms   +--------+          10ms  +----------+
+ *           \                                                   /
+ *            -------------------- udp face --------------------
+ *
+ * Consumer requests data from producer with frequency 10 interests per second
+ * (interests contain constantly increasing sequence number).
+ *
+ * For every received interest, producer replies with a data packet, containing
+ * 1024 bytes of virtual payload.
+ *
+ * To run scenario and see what is happening, use the following command:
+ *
+ *     NS_LOG=ndn.Consumer:ndn.Producer ./waf --run=ndn-simple-udp
+ */
+
+int 
+main (int argc, char *argv[])
+{
+  Packet::EnablePrinting ();
+  
+  // setting default parameters for PointToPoint links and channels
+  Config::SetDefault ("ns3::PointToPointNetDevice::DataRate", StringValue ("1Mbps"));
+  Config::SetDefault ("ns3::PointToPointChannel::Delay", StringValue ("10ms"));
+  Config::SetDefault ("ns3::DropTailQueue::MaxPackets", StringValue ("20"));
+
+  // Read optional command-line parameters (e.g., enable visualizer with ./waf --run=<> --visualize
+  CommandLine cmd;
+  cmd.Parse (argc, argv);
+
+  // Creating nodes
+  NodeContainer nodes;
+  nodes.Create (3);
+
+  // Connecting nodes using two links
+  PointToPointHelper p2p;
+  NetDeviceContainer link1 = p2p.Install (nodes.Get (0), nodes.Get (1));
+  NetDeviceContainer link2 = p2p.Install (nodes.Get (1), nodes.Get (2));
+
+  // Install NDN stack on all nodes
+  ndn::StackHelper ndnHelper;
+  ndnHelper.SetForwardingStrategy ("ns3::ndn::fw::BestRoute");
+  ndnHelper.SetDefaultRoutes (false);
+  ndnHelper.InstallAll ();
+
+  InternetStackHelper ipStack;
+  ipStack.SetIpv6StackInstall (false);
+  ipStack.InstallAll ();
+
+  Ipv4AddressHelper ipAddressHelper;
+  ipAddressHelper.SetBase (Ipv4Address ("10.1.1.0"), Ipv4Mask ("255.255.255.0"));
+  ipAddressHelper.Assign (link1);
+  
+  ipAddressHelper.SetBase (Ipv4Address ("10.1.2.0"), Ipv4Mask ("255.255.255.0"));
+  ipAddressHelper.Assign (link2);
+
+  Ipv4StaticRoutingHelper ipStaticRouting;
+  ipStaticRouting.GetStaticRouting (nodes.Get (0)->GetObject<Ipv4> ())->
+    AddNetworkRouteTo (Ipv4Address ("10.1.2.0"), Ipv4Mask ("255.255.255.0"),
+                       Ipv4Address ("10.1.1.2"),
+                       1, 1);
+
+  ipStaticRouting.GetStaticRouting (nodes.Get (2)->GetObject<Ipv4> ())->
+    AddNetworkRouteTo (Ipv4Address ("10.1.1.0"), Ipv4Mask ("255.255.255.0"),
+                       Ipv4Address ("10.1.2.1"),
+                       1, 1);
+  
+  ndn::IpFacesHelper::InstallAll ();
+  ndn::IpFacesHelper::CreateUdpFace (Seconds (1.0), nodes.Get (0), Ipv4Address ("10.1.2.2"), "/udp-route1");
+  ndn::IpFacesHelper::CreateUdpFace (Seconds (1.0), nodes.Get (0), Ipv4Address ("10.1.1.2"), "/udp-route2");
+  
+  // Installing applications
+
+  // Consumer
+  ndn::AppHelper consumerHelper ("ns3::ndn::ConsumerCbr");
+  // consumerHelper.SetAttribute ("Randomize", StringValue ("uniform"));
+  // Consumer will request /udp-route1/0, /udp-route1/1, ...
+  consumerHelper.SetPrefix ("/udp-route1");
+  consumerHelper.SetAttribute ("Frequency", StringValue ("10")); // 10 interests a second
+  consumerHelper.Install (nodes.Get (0)).
+    Start (Seconds (3)); // first node
+
+  // Consumer will request /udp-route1/0, /udp-route1/1, ...
+  consumerHelper.SetPrefix ("/udp-route2");
+  consumerHelper.SetAttribute ("Frequency", StringValue ("10")); // 10 interests a second
+  consumerHelper.Install (nodes.Get (0)).
+    Start (Seconds (3)); // first node
+  
+  // Producer
+  ndn::AppHelper producerHelper ("ns3::ndn::Producer");
+  // Producer will reply to all requests starting with /prefix
+  producerHelper.SetPrefix ("/udp-route1");
+  producerHelper.SetAttribute ("PayloadSize", StringValue("1024"));
+  producerHelper.Install (nodes.Get (2)); // last node
+
+  producerHelper.SetPrefix ("/udp-route2");
+  producerHelper.SetAttribute ("PayloadSize", StringValue("1024"));
+  producerHelper.Install (nodes.Get (1)); // last node
+
+  Simulator::Stop (Seconds (20.0));
+
+  Simulator::Run ();
+  Simulator::Destroy ();
+
+  return 0;
+}