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

//

// Copyright (c) 2006 Georgia Tech Research Corporation

// All rights reserved.

//

// 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: George F. Riley<riley@ece.gatech.edu>

//

#include "ns3/packet.h"

#include "ns3/debug.h"

#include "ipv4.h"

#include "ipv4-l4-protocol.h"

#include "ipv4-address.h"

#include "ipv4-header.h"

#include "ipv4-interface.h"

#include "ipv4-route.h"

// the two following headers are needed for Ipv4::ForwardUp

#include "node.h"

#include "ipv4-l4-demux.h"

NS_DEBUG_COMPONENT_DEFINE ("Ipv4");

namespace ns3 {

Ipv4::Ipv4(Node *node)

    m_defaultTtl (64),

    m_identification (0),

    m_defaultRoute (0),

    m_node (node)

{}

Ipv4::~Ipv4 ()

{

  // XXX I am not sure we are really allowed to do this here.

  for (Ipv4InterfaceList::iterator i = m_interfaces.begin (); i != m_interfaces.end (); i++)

    {

      delete (*i);

    }

  for (HostRoutesI i = m_hostRoutes.begin (); 

       i != m_hostRoutes.end (); 

       i = m_hostRoutes.erase (i)) 

    {

      delete (*i);

    }

  for (NetworkRoutesI j = m_networkRoutes.begin (); 

       j != m_networkRoutes.end (); 

       j = m_networkRoutes.erase (j)) 

    {

      delete (*j);

    }

  delete m_defaultRoute;

}

void 

Ipv4::SetDefaultTtl (uint8_t ttl)

{

  m_defaultTtl = ttl;

}

void 

Ipv4::AddHostRouteTo (Ipv4Address dest, 

				Ipv4Address nextHop, 

				uint32_t interface)

{

  Ipv4Route *route = new Ipv4Route ();

  *route = Ipv4Route::CreateHostRouteTo (dest, nextHop, interface);

  m_hostRoutes.push_back (route);

}

void 

Ipv4::AddHostRouteTo (Ipv4Address dest, 

				uint32_t interface)

{

  Ipv4Route *route = new Ipv4Route ();

  *route = Ipv4Route::CreateHostRouteTo (dest, interface);

  m_hostRoutes.push_back (route);

}

void 

Ipv4::AddNetworkRouteTo (Ipv4Address network, 

				   Ipv4Mask networkMask, 

				   Ipv4Address nextHop, 

				   uint32_t interface)

{

  Ipv4Route *route = new Ipv4Route ();

  *route = Ipv4Route::CreateNetworkRouteTo (network,

                                            networkMask,

                                            nextHop,

                                            interface);

  m_networkRoutes.push_back (route);

}

void 

Ipv4::AddNetworkRouteTo (Ipv4Address network, 

				   Ipv4Mask networkMask, 

				   uint32_t interface)

{

  Ipv4Route *route = new Ipv4Route ();

  *route = Ipv4Route::CreateNetworkRouteTo (network,

                                            networkMask,

                                            interface);

  m_networkRoutes.push_back (route);

}

void 

Ipv4::SetDefaultRoute (Ipv4Address nextHop, 

				 uint32_t interface)

{

  Ipv4Route *route = new Ipv4Route ();

  *route = Ipv4Route::CreateDefaultRoute (nextHop, interface);

  delete m_defaultRoute;

  m_defaultRoute = route;

}

Ipv4Route *

Ipv4::Lookup (Ipv4Address dest)

{

  for (HostRoutesCI i = m_hostRoutes.begin (); 

       i != m_hostRoutes.end (); 

       i++) 

    {

      NS_ASSERT ((*i)->IsHost ());

      if ((*i)->GetDest ().IsEqual (dest)) 

        {

          return (*i);

        }

    }

  for (NetworkRoutesI j = m_networkRoutes.begin (); 

       j != m_networkRoutes.end (); 

       j++) 

    {

      NS_ASSERT ((*j)->IsNetwork ());

      Ipv4Mask mask = (*j)->GetDestNetworkMask ();

      Ipv4Address entry = (*j)->GetDestNetwork ();

      if (mask.IsMatch (dest, entry)) 

        {

          return (*j);

        }

    }

  if (m_defaultRoute != 0) 

    {

      NS_ASSERT (m_defaultRoute->IsDefault ());

      return m_defaultRoute;

    }

  return 0;

}

uint32_t 

Ipv4::GetNRoutes (void)

{

  uint32_t n = 0;

  if (m_defaultRoute != 0)

    {

      n++;

    }

  n += m_hostRoutes.size ();

  n += m_networkRoutes.size ();

  return n;

}

Ipv4Route *

Ipv4::GetRoute (uint32_t index)

{

  if (index == 0 && m_defaultRoute != 0)

    {

      return m_defaultRoute;

    }

  if (index > 0 && m_defaultRoute != 0)

    {

      index--;

    }

  if (index < m_hostRoutes.size ())

    {

      uint32_t tmp = 0;

      for (HostRoutesCI i = m_hostRoutes.begin (); 

           i != m_hostRoutes.end (); 

           i++) 

        {

          if (tmp  == index)

            {

              return *i;

            }

          tmp++;

        }

    }

  index -= m_hostRoutes.size ();

  uint32_t tmp = 0;

  for (NetworkRoutesI j = m_networkRoutes.begin (); 

       j != m_networkRoutes.end (); 

       j++) 

    {

      if (tmp == index)

        {

          return *j;

        }

      tmp++;

    }

  NS_ASSERT (false);

  // quiet compiler.

  return 0;

}

void 

Ipv4::RemoveRoute (uint32_t index)

{

  if (index == 0 && m_defaultRoute != 0)

    {

      delete m_defaultRoute;

      m_defaultRoute = 0;

    }

  if (index > 0 && m_defaultRoute != 0)

    {

      index--;

    }

  if (index < m_hostRoutes.size ())

    {

      uint32_t tmp = 0;

      for (HostRoutesI i = m_hostRoutes.begin (); 

           i != m_hostRoutes.end (); 

           i++) 

        {

          if (tmp  == index)

            {

              delete *i;

              m_hostRoutes.erase (i);

              return;

            }

          tmp++;

        }

    }

  index -= m_hostRoutes.size ();

  uint32_t tmp = 0;

  for (NetworkRoutesI j = m_networkRoutes.begin (); 

       j != m_networkRoutes.end (); 

       j++) 

    {

      if (tmp == index)

        {

          delete *j;

          m_networkRoutes.erase (j);

          return;

        }

      tmp++;

    }

  NS_ASSERT (false);

}

uint32_t 

Ipv4::AddInterface (Ipv4Interface *interface)

{

  uint32_t index = m_nInterfaces;

  m_interfaces.push_back (interface);

  m_nInterfaces++;

  return index;

}

Ipv4Interface *

Ipv4::GetInterface (uint32_t index)

{

  uint32_t tmp = 0;

  for (Ipv4InterfaceList::const_iterator i = m_interfaces.begin (); i != m_interfaces.end (); i++)

    {

      if (index == tmp) 

	{

	  return *i;

	}

      tmp++;

    }

  return 0;

}

uint32_t 

Ipv4::GetNInterfaces (void) const

{

  return m_nInterfaces;

}

Ipv4Interface *

Ipv4::FindInterfaceForDevice (NetDevice const*device)

{

  for (Ipv4InterfaceList::const_iterator i = m_interfaces.begin (); i != m_interfaces.end (); i++)

    {

      if ((*i)->GetDevice () == device)

        {

          return *i;

        }

    }

  return 0;

}  

Ipv4* 

Ipv4::Copy(Node *node) const

{

  Ipv4 *ipv4 = new Ipv4 (node);

  ipv4->SetDefaultTtl (m_defaultTtl);

  return ipv4;

}

void 

Ipv4::Receive(Packet& packet, NetDevice &device)

{

  // XXX trace here.

  Ipv4Header ipHeader;

  packet.Peek (ipHeader);

  packet.Remove (ipHeader);

  if (!ipHeader.IsChecksumOk ()) 

    {

      return;

    }

  if (Forwarding (packet, ipHeader, device)) 

    {

      return;

    }

  ForwardUp (packet, ipHeader);

}

void 

Ipv4::Send (Packet const &packet, 

                      Ipv4Address source, 

                      Ipv4Address destination,

                      uint8_t protocol)

{

  Ipv4Header ipHeader;

  ipHeader.SetSource (source);

  ipHeader.SetDestination (destination);

  ipHeader.SetProtocol (protocol);

  ipHeader.SetPayloadSize (packet.GetSize ());

  ipHeader.SetTtl (m_defaultTtl);

  ipHeader.SetMayFragment ();

  ipHeader.SetIdentification (m_identification);

  m_identification ++;

  // XXX Note here that in most ipv4 stacks in the world,

  // the route calculation for an outgoing packet is not

  // done in the ip layer. It is done within the application

  // socket when the first packet is sent to avoid this

  // costly lookup on a per-packet basis.

  // That would require us to get the route from the packet,

  // most likely with a packet tag. The higher layers do not

  // do this yet for us.

  Ipv4Route *route = Lookup (ipHeader.GetDestination ());

  if (route == 0) 

    {

      NS_DEBUG ("not for me -- forwarding but no route to host. drop.");

      return;

    }

  SendRealOut (packet, ipHeader, *route);

}

void

Ipv4::SendRealOut (Packet const &p, Ipv4Header const &ip, Ipv4Route const &route)

{

  Packet packet = p;

  packet.Add (ip);

  Ipv4Interface *outInterface = GetInterface (route.GetInterface ());

  NS_ASSERT (packet.GetSize () <= outInterface->GetMtu ());

  // XXX log trace here.

  if (route.IsGateway ()) 

    {

      outInterface->Send (packet, route.GetGateway ());

    } 

  else 

    {

      outInterface->Send (packet, ip.GetDestination ());

    }

}

bool

Ipv4::Forwarding (Packet const &packet, Ipv4Header &ipHeader, NetDevice &device)

{

  for (Ipv4InterfaceList::const_iterator i = m_interfaces.begin ();

       i != m_interfaces.end (); i++) 

    {

      if ((*i)->GetAddress ().IsEqual (ipHeader.GetDestination ())) 

        {

          NS_DEBUG ("for me 1");

          return false;

        }

    }

  for (Ipv4InterfaceList::const_iterator i = m_interfaces.begin ();

       i != m_interfaces.end (); i++) 

    {

      Ipv4Interface *interface = *i;

      if (interface->GetDevice () == &device)

	{

	  if (ipHeader.GetDestination ().IsEqual (interface->GetBroadcast ())) 

	    {

	      NS_DEBUG ("for me 2");

	      return false;

	    }

	  break;

	}

    }

  if (ipHeader.GetDestination ().IsEqual (Ipv4Address::GetBroadcast ())) 

    {

      NS_DEBUG ("for me 3");

      return false;

    }

  if (ipHeader.GetDestination ().IsEqual (Ipv4Address::GetAny ())) 

    {

      NS_DEBUG ("for me 4");

      return false;

    }

  if (ipHeader.GetTtl () == 1) 

    {

      // Should send ttl expired here

      // XXX

      NS_DEBUG ("not for me -- ttl expired. drop.");

      return true;

    }

  ipHeader.SetTtl (ipHeader.GetTtl () - 1);

  Ipv4Route *route = Lookup (ipHeader.GetDestination ());

  if (route == 0) 

    {

      NS_DEBUG ("not for me -- forwarding but no route to host. drop.");

      return true;

    }

  NS_DEBUG ("not for me -- forwarding.");

  SendRealOut (packet, ipHeader, *route);

  return true;

}

void

Ipv4::ForwardUp (Packet p, Ipv4Header const&ip)

{

  Ipv4L4Protocol *protocol = m_node->GetIpv4L4Demux ()->Lookup (ip.GetProtocol ());

  protocol->Receive (p, ip.GetSource (), ip.GetDestination ());

}

}//namespace ns3