/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2011 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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: Jaume Nin <jnin@cttc.es>

 *         Nicola Baldo <nbaldo@cttc.es>

 */

#include <ns3/epc-helper.h>

#include <ns3/log.h>

#include <ns3/inet-socket-address.h>

#include <ns3/mac48-address.h>

#include <ns3/epc-gtpu-tunnel-endpoint.h>

#include <ns3/eps-bearer.h>

#include <ns3/ipv4-address.h>

#include <ns3/internet-stack-helper.h>

#include <ns3/point-to-point-helper.h>

#include <ns3/packet-socket-helper.h>

#include <ns3/packet-socket-address.h>

#include <ns3/epc-enb-application.h>

#include <ns3/epc-sgw-pgw-application.h>

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("EpcHelper");

NS_OBJECT_ENSURE_REGISTERED (EpcHelper);

EpcHelper::EpcHelper () 

  : m_gtpuUdpPort (2152) // fixed by the standard

{

  NS_LOG_FUNCTION (this);

  // since we use point-to-point links for all S1-U links, 

  // we use a /30 subnet which can hold exactly two addresses 

  // (remember that net broadcast and null address are not valid)

  m_s1uIpv4AddressHelper.SetBase ("10.0.0.0", "255.255.255.252");

  // we use a /8 net for all UEs

  m_ueAddressHelper.SetBase ("7.0.0.0", "255.0.0.0");

  // create SgwPgwNode

  m_sgwPgw = CreateObject<Node> ();

  InternetStackHelper internet;

  internet.Install (m_sgwPgw);

  // create S1-U socket

  Ptr<Socket> sgwPgwS1uSocket = Socket::CreateSocket (m_sgwPgw, TypeId::LookupByName ("ns3::UdpSocketFactory"));

  int retval = sgwPgwS1uSocket->Bind (InetSocketAddress (Ipv4Address::GetAny (), m_gtpuUdpPort));

  NS_ASSERT (retval == 0);

  // create TUN device implementing tunneling of user data over GTP-U/UDP/IP 

  // yes we need this

  // the TUN device is on the same subnet as the UEs, so when a packet

  // addressed to an UE arrives at the intenet to the WAN interface of

  // the PGW it will be forwarded to the TUN device. 

  // create EpcSgwPgwApplication

  m_sgwPgw->AddApplication (m_sgwPgwApp);

  // connect SgwPgwApplication and virtual net device for tunneling

}

EpcHelper::~EpcHelper ()

{

  NS_LOG_FUNCTION (this);

}

TypeId

EpcHelper::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::EpcHelper")

    .SetParent<Object> ()

    .AddConstructor<EpcHelper> ()

    .AddAttribute ("S1uLinkDataRate", 

                   "The data rate to be used for the next S1-U link to be created",

                   DataRateValue (DataRate ("10Gb/s")),

                   MakeDataRateAccessor (&EpcHelper::m_s1uLinkDataRate),

                   MakeDataRateChecker ())

    .AddAttribute ("S1uLinkDelay", 

                   "The delay to be used for the next S1-U link to be created",

                   TimeValue (Seconds (0)),

                   MakeTimeAccessor (&EpcHelper::m_s1uLinkDelay),

                   MakeTimeChecker ())

    .AddAttribute ("S1uLinkMtu", 

                   "The MTU of the next S1-U link to be created. Note that, because of the additional GTP/UDP/IP tunneling overhead, you need a MTU larger than the end-to-end MTU that you want to support.",

                   UintegerValue (2000),

                   MakeUintegerAccessor (&EpcHelper::m_s1uLinkMtu),

                   MakeUintegerChecker<uint16_t> ())

  ;

  return tid;

}

void

EpcHelper::AddEnb (Ptr<Node> enb, Ptr<NetDevice> lteEnbNetDevice)

{

  NS_LOG_FUNCTION (this << enb << lteEnbNetDevice);

  NS_ASSERT (enb == lteEnbNetDevice->GetNode ());

  // add an IPv4 stack to the previously created eNB

  InternetStackHelper internet;

  internet.Install (enb);

  NS_LOG_LOGIC ("number of Ipv4 ifaces of the eNB after node creation: " << enb->GetObject<Ipv4> ()->GetNInterfaces ());

  // create a point to point link between the new eNB and the SGW with

  // the corresponding new NetDevices on each side  

  NodeContainer enbSgwNodes;

  enbSgwNodes.Add (m_sgwPgw);

  enbSgwNodes.Add (enb);

  PointToPointHelper p2ph;

  p2ph.SetDeviceAttribute ("DataRate", DataRateValue (m_s1uLinkDataRate));

  p2ph.SetDeviceAttribute ("Mtu", UintegerValue (m_s1uLinkMtu));

  p2ph.SetChannelAttribute ("Delay", TimeValue (m_s1uLinkDelay));  

  NetDeviceContainer enbSgwDevices = p2ph.Install (enb, m_sgwPgw);

  NS_LOG_LOGIC ("number of Ipv4 ifaces of the eNB after installing p2p dev: " << enb->GetObject<Ipv4> ()->GetNInterfaces ());  

  Ptr<NetDevice> enbDev = enbSgwDevices.Get (0);

  Ptr<NetDevice> sgwDev = enbSgwDevices.Get (1);

  m_s1uIpv4AddressHelper.NewNetwork ();

  Ipv4InterfaceContainer enbSgwIpIfaces = m_s1uIpv4AddressHelper.Assign (enbSgwDevices);

  NS_LOG_LOGIC ("number of Ipv4 ifaces of the eNB after assigning Ipv4 addr to S1 dev: " << enb->GetObject<Ipv4> ()->GetNInterfaces ());

  Ipv4Address enbAddress = enbSgwIpIfaces.GetAddress (0);

  Ipv4Address sgwAddress = enbSgwIpIfaces.GetAddress (1);

  // create S1-U socket for the ENB

  Ptr<Socket> enbS1uSocket = Socket::CreateSocket (enb, TypeId::LookupByName ("ns3::UdpSocketFactory"));

  int retval = enbS1uSocket->Bind (InetSocketAddress (enbAddress, m_gtpuUdpPort));

  NS_ASSERT (retval == 0);

  // give PacketSocket powers to the eNB

  //PacketSocketHelper packetSocket;

  //packetSocket.Install (enb); 

  // create LTE socket for the ENB 

  Ptr<Socket> enbLteSocket = Socket::CreateSocket (enb, TypeId::LookupByName ("ns3::PacketSocketFactory"));

  PacketSocketAddress enbLteSocketBindAddress;

  enbLteSocketBindAddress.SetSingleDevice (lteEnbNetDevice->GetIfIndex ());

  retval = enbLteSocket->Bind (enbLteSocketBindAddress);

  NS_ASSERT (retval == 0);  

  PacketSocketAddress enbLteSocketConnectAddress;

  enbLteSocketConnectAddress.SetPhysicalAddress (Mac48Address::GetBroadcast ());

  enbLteSocketConnectAddress.SetSingleDevice (lteEnbNetDevice->GetIfIndex ());

  enbLteSocketConnectAddress.SetProtocol (Ipv4L3Protocol::PROT_NUMBER);

  retval = enbLteSocket->Connect (enbLteSocketConnectAddress);

  NS_ASSERT (retval == 0);  

  NS_LOG_INFO ("create EpcEnbApplication");

  Ptr<EpcEnbApplication> enbApp = CreateObject<EpcEnbApplication> (enbLteSocket, enbS1uSocket, sgwAddress);

  enb->AddApplication (enbApp);

  NS_ASSERT (enb->GetNApplications () == 1);

  NS_ASSERT_MSG (enb->GetApplication (0)->GetObject<EpcEnbApplication> () != 0, "cannot retrieve EpcEnbApplication");

  NS_LOG_LOGIC ("enb: " << enb << ", enb->GetApplication (0): " << enb->GetApplication (0));

}

void

EpcHelper::ActivateEpsBearer (Ptr<NetDevice> ueLteDevice, Ptr<NetDevice> enbLteDevice, Ptr<LteTft> tft, uint16_t rnti, uint8_t lcid)

{

  Ptr<Node> ueNode = ueLteDevice->GetNode (); 

  Ptr<Ipv4> ueIpv4 = ueNode->GetObject<Ipv4> ();

  int32_t interface =  ueIpv4->GetInterfaceForDevice (ueLteDevice);

  NS_ASSERT (interface >= 0);

  NS_ASSERT (ueIpv4->GetNAddresses (interface) == 1);

  Ipv4Address ueAddr = ueIpv4->GetAddress (interface, 0).GetLocal ();

  NS_LOG_LOGIC (" UE IP address: " << ueAddr);

  // NOTE: unlike ueLteDevice, enbLteDevice is NOT an Ipv4 enabled

  // device. In fact we are interested in the S1 device of the eNB.

  // We find it by relying on the assumption that the S1 device is the

  // only Ipv4 enabled device of the eNB besides the localhost interface.

  Ptr<Node> enbNode = enbLteDevice->GetNode (); 

  NS_ASSERT (enbNode != 0);

  Ptr<Ipv4> enbIpv4 = enbNode->GetObject<Ipv4> ();

  NS_LOG_LOGIC ("number of Ipv4 ifaces of the eNB: " << enbIpv4->GetNInterfaces ());

  // two ifaces total: loopback + the S1-U interface

  NS_ASSERT (enbIpv4->GetNInterfaces () == 2); 

  NS_ASSERT (ueIpv4->GetNAddresses (1) == 1);

  // iface index 0 is loopback, index 1 is the S1-U interface

  Ipv4Address enbAddr = enbIpv4->GetAddress (1, 0).GetLocal (); 

  NS_LOG_LOGIC (" ENB IP address: " << enbAddr);

  // setup S1 bearer at EpcSgwPgwApplication

  uint32_t teid = m_sgwPgwApp->ActivateS1Bearer (ueAddr, enbAddr, tft);

  // setup S1 bearer at EpcEnbApplication

  NS_LOG_LOGIC ("enb: " << enbNode << ", enb->GetApplication (0): " << enbNode->GetApplication (0));

  NS_ASSERT (enbNode->GetNApplications () == 1);

  Ptr<Application> app =  enbNode->GetApplication (0);

  NS_ASSERT (app != 0);

  Ptr<EpcEnbApplication> epcEnbApp = app->GetObject<EpcEnbApplication> ();

  NS_ASSERT (epcEnbApp != 0);

  epcEnbApp->ErabSetupRequest (teid, rnti, lcid);

}

Ptr<Node>

EpcHelper::GetPgwNode ()

{

  return m_sgwPgw;

}

Ipv4InterfaceContainer 

EpcHelper::AssignUeIpv4Address (NetDeviceContainer ueDevices)

{

  return m_ueAddressHelper.Assign (ueDevices);

}

} // namespace ns3