/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2007-2009 Strasbourg University
 *
 * 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: Sebastien Vincent <vincent@clarinet.u-strasbg.fr>
 */

#include "ns3/log.h"
#include "ns3/node.h"
#include "ns3/uinteger.h"
#include "ns3/vector.h"
#include "ns3/callback.h"
#include "ns3/trace-source-accessor.h"
#include "ns3/object-vector.h"
#include "ns3/ipv6-routing-protocol.h"
#include "ns3/ipv6-route.h"

#include "loopback-net-device.h"
#include "ipv6-l3-protocol.h"
#include "ipv6-l4-protocol.h"
#include "ipv6-interface.h"
#include "ipv6-raw-socket-impl.h"
#include "ipv6-autoconfigured-prefix.h"
#include "icmpv6-l4-protocol.h"
#include "ndisc-cache.h"

namespace ns3
{

NS_OBJECT_ENSURE_REGISTERED (Ipv6L3Protocol);

NS_LOG_COMPONENT_DEFINE ("Ipv6L3Protocol");

const uint16_t Ipv6L3Protocol::PROT_NUMBER = 0x86DD;

TypeId Ipv6L3Protocol::GetTypeId ()
{
  static TypeId tid = TypeId ("ns3::Ipv6L3Protocol")
    .SetParent<Ipv6> ()
    .AddConstructor<Ipv6L3Protocol> ()
    .AddAttribute ("DefaultTtl", "The TTL value set by default on all outgoing packets generated on this node.",
                   UintegerValue (64),
                   MakeUintegerAccessor (&Ipv6L3Protocol::m_defaultTtl),
                   MakeUintegerChecker<uint8_t> ())
    .AddTraceSource ("Tx", "Send IPv6 packet to outgoing interface.",
                   MakeTraceSourceAccessor (&Ipv6L3Protocol::m_txTrace))
    .AddTraceSource ("Rx", "Receive IPv6 packet from incoming interface.",
                     MakeTraceSourceAccessor (&Ipv6L3Protocol::m_rxTrace))
    .AddTraceSource ("Drop", "Drop IPv6 packet",
                     MakeTraceSourceAccessor (&Ipv6L3Protocol::m_dropTrace))
    .AddAttribute ("InterfaceList", "The set of IPv6 interfaces associated to this IPv6 stack.",
                   ObjectVectorValue (),
                   MakeObjectVectorAccessor (&Ipv6L3Protocol::m_interfaces),
                   MakeObjectVectorChecker<Ipv6Interface> ())
    ;
  return tid;
}

Ipv6L3Protocol::Ipv6L3Protocol ()
  : m_nInterfaces (0)
{
  NS_LOG_FUNCTION_NOARGS ();
}

Ipv6L3Protocol::~Ipv6L3Protocol ()
{
  NS_LOG_FUNCTION_NOARGS ();
}

void Ipv6L3Protocol::DoDispose ()
{
  NS_LOG_FUNCTION_NOARGS ();
  
  /* clear protocol and interface list */
  for (L4List_t::iterator it = m_protocols.begin () ; it != m_protocols.end () ; ++it)
  {
    *it = 0;
  }
  m_protocols.clear ();

  /* remove interfaces */
  for (Ipv6InterfaceList::iterator it = m_interfaces.begin () ; it != m_interfaces.end (); ++it)
  {
    *it = 0;
  }
  m_interfaces.clear ();

  /* remove raw sockets */
  for (SocketList::iterator it = m_sockets.begin () ; it != m_sockets.end () ; ++it)
  {
    *it = 0;
  }
  m_sockets.clear ();

  /* remove list of prefix */
  for (Ipv6AutoconfiguredPrefixListI it = m_prefixes.begin () ; it != m_prefixes.end () ; ++it)
  {
    (*it)->StopValidTimer ();
    (*it)->StopPreferredTimer ();
    (*it) = 0;
  }
  m_prefixes.clear ();


  m_node = 0;
  m_routingProtocol = 0;
  Object::DoDispose ();
}

void Ipv6L3Protocol::SetRoutingProtocol (Ptr<Ipv6RoutingProtocol> routingProtocol)
{
  NS_LOG_FUNCTION (this << routingProtocol);
  m_routingProtocol = routingProtocol;
  m_routingProtocol->SetIpv6 (this);
}

Ptr<Ipv6RoutingProtocol> Ipv6L3Protocol::GetRoutingProtocol () const 
{
  NS_LOG_FUNCTION_NOARGS ();
  return m_routingProtocol;
}

uint32_t Ipv6L3Protocol::AddInterface (Ptr<NetDevice> device)
{
  NS_LOG_FUNCTION (this << device);
  Ptr<Node> node = GetObject<Node> ();
  Ptr<Ipv6Interface> interface = CreateObject<Ipv6Interface> ();
  
  node->RegisterProtocolHandler (MakeCallback (&Ipv6L3Protocol::Receive, this), Ipv6L3Protocol::PROT_NUMBER, device);
  interface->SetNode (m_node);
  interface->SetDevice (device);
  interface->SetForwarding (m_ipForward);
  return AddIpv6Interface (interface);
}

uint32_t Ipv6L3Protocol::AddIpv6Interface (Ptr<Ipv6Interface> interface)
{
  NS_LOG_FUNCTION (this << interface);
  uint32_t index = m_nInterfaces;

  m_interfaces.push_back (interface);
  m_nInterfaces++;
  return index;
}

Ptr<Ipv6Interface> Ipv6L3Protocol::GetInterface (uint32_t index) const
{
  NS_LOG_FUNCTION (this << index);
  uint32_t tmp = 0;
  
  for (Ipv6InterfaceList::const_iterator it = m_interfaces.begin () ; it != m_interfaces.end () ; it++)
  {
    if (index == tmp)
    {
      return *it;
    }
    tmp++;
  }
  return 0;
}

uint32_t Ipv6L3Protocol::GetNInterfaces () const 
{
  NS_LOG_FUNCTION_NOARGS ();
  return m_nInterfaces;
}

int32_t Ipv6L3Protocol::GetInterfaceForAddress (Ipv6Address address) const
{
  NS_LOG_FUNCTION (this << address); 
  int32_t index = 0;

  for (Ipv6InterfaceList::const_iterator it = m_interfaces.begin () ; it != m_interfaces.end () ; it++)
  {
    uint32_t j = 0;
    uint32_t max = (*it)->GetNAddresses ();

    for (j = 0 ; j < max ; j++)
    {
      if ((*it)->GetAddress (j).GetAddress () == address) 
      {
        return index;
      }
    }
    index++;
  }
  return -1;
}

int32_t Ipv6L3Protocol::GetInterfaceForPrefix (Ipv6Address address, Ipv6Prefix mask) const
{
  NS_LOG_FUNCTION (this << address << mask);
  int32_t index = 0;

  for (Ipv6InterfaceList::const_iterator it = m_interfaces.begin () ; it != m_interfaces.end () ; it++)
  {
    uint32_t j = 0;
    for (j = 0 ; j < (*it)->GetNAddresses () ; j++)
    {
      if ((*it)->GetAddress (j).GetAddress ().CombinePrefix (mask) == address.CombinePrefix (mask))
      {
        return index;
      }
    }
    index++;
  }
  return -1;
}

Ptr<NetDevice> Ipv6L3Protocol::GetNetDevice (uint32_t i)
{
  NS_LOG_FUNCTION (this << i);
  return GetInterface (i)->GetDevice ();
}

int32_t Ipv6L3Protocol::GetInterfaceForDevice (Ptr<const NetDevice> device) const
{
  NS_LOG_FUNCTION (this << device);
  int32_t index = 0;

  for (Ipv6InterfaceList::const_iterator it = m_interfaces.begin () ; it != m_interfaces.end () ; it++)
  {
    if ((*it)->GetDevice () == device)
    {
      return index;
    }
    index++;
  }
  return -1;
}

void Ipv6L3Protocol::AddAutoconfiguredAddress (uint32_t interface, Ipv6Address network, Ipv6Prefix mask, uint8_t flags, uint32_t validTime, uint32_t preferredTime, Ipv6Address defaultRouter)
{
  NS_LOG_FUNCTION (this << interface << network << mask << (uint32_t)flags << validTime << preferredTime);
  Ipv6InterfaceAddress address;

  Address addr = GetInterface (interface)->GetDevice ()->GetAddress ();

  if (flags & (1<< 6)) /* auto flag */
  {
    /* XXX : add other L2 address case */
    if (Mac48Address::IsMatchingType (addr))
    {
      address = Ipv6InterfaceAddress (Ipv6Address::MakeAutoconfiguredAddress (Mac48Address::ConvertFrom (addr), network));
    }
    else
    {
      NS_FATAL_ERROR ("Unknown method to make autoconfigured address for this kind of device.");
      return;
    }

    /* see if we have already the prefix */
    for (Ipv6AutoconfiguredPrefixListI it = m_prefixes.begin () ; it != m_prefixes.end () ; ++it)
    {
      if ((*it)->GetInterface () == interface && (*it)->GetPrefix () == network && (*it)->GetMask () == mask)
      {
        (*it)->StopPreferredTimer ();
        (*it)->StopValidTimer ();
        (*it)->StartPreferredTimer ();
        return;
      }
    }
    
    /* no prefix found, add autoconfigured address and the prefix */
    NS_LOG_INFO ("Autoconfigured address is :" << address.GetAddress ());
    AddAddress (interface, address);

    /* add default router
     * if a previous default route exists, the new ones is simply added 
     */
    GetRoutingProtocol ()->NotifyAddRoute (Ipv6Address::GetAny (), Ipv6Prefix ((uint8_t)0), defaultRouter, interface, network);

    Ptr<Ipv6AutoconfiguredPrefix> aPrefix = CreateObject<Ipv6AutoconfiguredPrefix> (m_node, interface, network, mask, preferredTime, validTime, defaultRouter);
    aPrefix->StartPreferredTimer ();

    m_prefixes.push_back (aPrefix);
  }
}

void Ipv6L3Protocol::RemoveAutoconfiguredAddress (uint32_t interface, Ipv6Address network, Ipv6Prefix mask, Ipv6Address defaultRouter)
{
  NS_LOG_FUNCTION (this << interface << network << mask);
  Ptr<Ipv6Interface> iface = GetInterface (interface);
  Address addr = iface->GetDevice ()->GetAddress ();
  uint32_t max = iface->GetNAddresses ();
  uint32_t i = 0;
  Ipv6Address toFound = Ipv6Address::MakeAutoconfiguredAddress (Mac48Address::ConvertFrom (addr), network);

  for (i = 0 ; i < max ; i++)
  {
    if (iface->GetAddress (i).GetAddress () == toFound) 
    {
      RemoveAddress (interface, i);
      break;
    }
  }

  /* remove from list of autoconfigured address */
  for (Ipv6AutoconfiguredPrefixListI it = m_prefixes.begin () ; it != m_prefixes.end () ; ++it)
  {
    if ((*it)->GetInterface () == interface && (*it)->GetPrefix () == network && (*it)->GetMask () == mask)
    {
      *it = 0;
      m_prefixes.erase (it);
      break;
    }
  }

  GetRoutingProtocol ()->NotifyRemoveRoute (Ipv6Address::GetAny (), Ipv6Prefix ((uint8_t)0), defaultRouter, interface, network);
}

bool Ipv6L3Protocol::AddAddress (uint32_t i, Ipv6InterfaceAddress address)
{
  NS_LOG_FUNCTION (this << i << address);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  bool ret = interface->AddAddress (address);

  if (m_routingProtocol != 0)
  {
    m_routingProtocol->NotifyAddAddress (i, address);
  }
  return ret;
}

uint32_t Ipv6L3Protocol::GetNAddresses (uint32_t i) const
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  return interface->GetNAddresses ();
}

Ipv6InterfaceAddress Ipv6L3Protocol::GetAddress (uint32_t i, uint32_t addressIndex) const
{
  NS_LOG_FUNCTION (this << i << addressIndex);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  return interface->GetAddress (addressIndex);
}

bool Ipv6L3Protocol::RemoveAddress (uint32_t i, uint32_t addressIndex)
{
  NS_LOG_FUNCTION (this << i << addressIndex);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  Ipv6InterfaceAddress address = interface->RemoveAddress (addressIndex);
  
  if (address != Ipv6InterfaceAddress ())
  {
    if (m_routingProtocol != 0)
    {
      m_routingProtocol->NotifyRemoveAddress (i, address);
    }
    return true;
  }
  return false;
}

void Ipv6L3Protocol::SetMetric (uint32_t i, uint16_t metric) 
{
  NS_LOG_FUNCTION (this << i << metric);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  interface->SetMetric (metric);
}

uint16_t Ipv6L3Protocol::GetMetric (uint32_t i) const 
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  return interface->GetMetric ();
}

uint16_t Ipv6L3Protocol::GetMtu (uint32_t i) const
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  return interface->GetDevice ()->GetMtu ();
}

bool Ipv6L3Protocol::IsUp (uint32_t i) const
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  return interface->IsUp ();
}

void Ipv6L3Protocol::SetUp (uint32_t i)
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  
  interface->SetUp ();
  
  if (m_routingProtocol != 0)
  {
    m_routingProtocol->NotifyInterfaceUp (i);
  }
}

void Ipv6L3Protocol::SetDown (uint32_t i)
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  
  interface->SetDown ();
  
  if (m_routingProtocol != 0)
  {
    m_routingProtocol->NotifyInterfaceDown (i);
  }
}

void Ipv6L3Protocol::SetupLoopback ()
{
  NS_LOG_FUNCTION_NOARGS ();
  Ptr<Ipv6Interface> interface = CreateObject<Ipv6Interface> ();
  Ptr<LoopbackNetDevice> device = 0;
  uint32_t i = 0;

  /* see if we have already an loopback NetDevice */
  for (i = 0 ; i < m_node->GetNDevices () ; i++)
  {
    if (device = DynamicCast<LoopbackNetDevice> (m_node->GetDevice (i)))
    {
      break;
    }
  }

  if (device == 0)
  {
    device = CreateObject<LoopbackNetDevice> ();
    m_node->AddDevice (device);
  }

  interface->SetDevice (device);
  interface->SetNode (m_node);
  Ipv6InterfaceAddress ifaceAddr = Ipv6InterfaceAddress (Ipv6Address::GetLoopback (), Ipv6Prefix (128));
  interface->AddAddress (ifaceAddr);
  uint32_t index = AddIpv6Interface (interface);
  Ptr<Node> node = GetObject<Node> ();
  node->RegisterProtocolHandler (MakeCallback (&Ipv6L3Protocol::Receive, this), Ipv6L3Protocol::PROT_NUMBER, device);
  interface->SetUp ();
  
  if (m_routingProtocol != 0)
  {
    m_routingProtocol->NotifyInterfaceUp (index);
  }
}

bool Ipv6L3Protocol::IsForwarding (uint32_t i) const
{
  NS_LOG_FUNCTION (this << i);
  Ptr<Ipv6Interface> interface = GetInterface (i);

  NS_LOG_LOGIC ("Forwarding state: " << interface->IsForwarding ());
  return interface->IsForwarding ();
}

void Ipv6L3Protocol::SetForwarding (uint32_t i, bool val)
{
  NS_LOG_FUNCTION (this << i << val);
  Ptr<Ipv6Interface> interface = GetInterface (i);
  interface->SetForwarding (val);
}

void Ipv6L3Protocol::SetIpForward (bool forward)
{
  NS_LOG_FUNCTION (this << forward);
  m_ipForward = forward;

  for (Ipv6InterfaceList::const_iterator it = m_interfaces.begin () ; it != m_interfaces.end (); it++)
  {
    (*it)->SetForwarding (forward);
  }
}

bool Ipv6L3Protocol::GetIpForward () const
{
  NS_LOG_FUNCTION_NOARGS ();
  return m_ipForward;
}

void Ipv6L3Protocol::NotifyNewAggregate ()
{
  NS_LOG_FUNCTION_NOARGS ();

  if (m_node == 0)
  {
    Ptr<Node> node = this->GetObject<Node> ();
    // verify that it's a valid node and that
    // the node has not been set before
    if (node != 0)
    {
      this->SetNode (node);
    }
  }
  Object::NotifyNewAggregate ();
}

void Ipv6L3Protocol::SetNode (Ptr<Node> node)
{
  NS_LOG_FUNCTION (this << node);
  m_node = node;
  /* add LoopbackNetDevice if needed, and an Ipv6Interface on top of it */
  SetupLoopback ();
}

void Ipv6L3Protocol::Insert (Ptr<Ipv6L4Protocol> protocol)
{
  NS_LOG_FUNCTION (this << protocol);
  m_protocols.push_back (protocol);
}

void Ipv6L3Protocol::Remove (Ptr<Ipv6L4Protocol> protocol)
{
  NS_LOG_FUNCTION (this << protocol);
  m_protocols.remove (protocol);
}

Ptr<Ipv6L4Protocol> Ipv6L3Protocol::GetProtocol (int protocolNumber) const
{
  NS_LOG_FUNCTION (this << protocolNumber);

  for (L4List_t::const_iterator i = m_protocols.begin () ; i != m_protocols.end () ; ++i)
  {
    if ((*i)->GetProtocolNumber () == protocolNumber)
    {
      return *i;
    }
  }
  return 0;
}

Ptr<Socket> Ipv6L3Protocol::CreateRawSocket ()
{
  NS_LOG_FUNCTION_NOARGS ();
  Ptr<Ipv6RawSocketImpl> sock = CreateObject<Ipv6RawSocketImpl> ();
  sock->SetNode (m_node);
  m_sockets.push_back (sock);
  return sock;
}

void Ipv6L3Protocol::DeleteRawSocket (Ptr<Socket> socket)
{
  NS_LOG_FUNCTION (this << socket);
  
  for (SocketList::iterator it = m_sockets.begin () ; it != m_sockets.end () ; ++it)
  {
    if ((*it) == socket)
    {
      m_sockets.erase (it);
      return;
    }
  }
}

Ptr<Icmpv6L4Protocol> Ipv6L3Protocol::GetIcmpv6 () const
{
  NS_LOG_FUNCTION_NOARGS ();
  Ptr<Ipv6L4Protocol> protocol = GetProtocol (Icmpv6L4Protocol::GetStaticProtocolNumber ());
  
  if (protocol)
  {
    return protocol->GetObject<Icmpv6L4Protocol> ();
  }
  else
  {
    return 0;
  }
}

void Ipv6L3Protocol::SetDefaultTtl (uint8_t ttl)
{
  NS_LOG_FUNCTION (this << ttl);
  m_defaultTtl = ttl;
}

void Ipv6L3Protocol::Send (Ptr<Packet> packet, Ipv6Address source, Ipv6Address destination, uint8_t protocol, Ptr<Ipv6Route> route)
{
  NS_LOG_FUNCTION (this << packet << source << destination << (uint32_t)protocol << route);
  Ipv6Header hdr;
  uint8_t ttl = m_defaultTtl;
  SocketIpTtlTag tag;
  bool found = packet->RemovePacketTag (tag);
  
  if (found)
  {
    ttl = tag.GetTtl ();
  }

  /* Handle 3 cases:
   * 1) Packet is passed in with a route entry
   * 2) Packet is passed in with a route entry but route->GetGateway is not set (e.g., same network)
   * 3) route is NULL (e.g., a raw socket call or ICMPv6)
   */

  /* 1) */
  if (route && route->GetGateway () != Ipv6Address::GetZero ())
  {
    NS_LOG_LOGIC ("Ipv6L3Protocol::Send case 1: passed in with a route");
    hdr = BuildHeader (source, destination, protocol, packet->GetSize (), ttl);
    SendRealOut (route, packet, hdr);
    return;
  }
  
  /* 2) */
  if (route && route->GetGateway () == Ipv6Address::GetZero ())
  {
    NS_LOG_LOGIC ("Ipv6L3Protocol::Send case 1: probably sent to machine on same IPv6 network");
    /* NS_FATAL_ERROR ("This case is not yet implemented"); */
    hdr = BuildHeader (source, destination, protocol, packet->GetSize (), ttl);
    SendRealOut (route, packet, hdr);
    return;
  }

  /* 3) */
  NS_LOG_LOGIC ("Ipv6L3Protocol::Send case 3: passed in with no route " << destination);
  Socket::SocketErrno err;
  uint32_t oif = 0;
  Ptr<Ipv6Route> newRoute = 0;

  hdr = BuildHeader (source, destination, protocol, packet->GetSize (), ttl);

  if (!source.IsAny ())
  {
    int32_t index = GetInterfaceForAddress (source);
    NS_ASSERT (index >= 0);
    oif = index;
  }

  newRoute = m_routingProtocol->RouteOutput (packet, hdr, oif, err);

  if (newRoute)
  {
    SendRealOut (newRoute, packet, hdr);
  }
  else
  {
    NS_LOG_WARN ("No route to host, drop!");
    m_dropTrace (hdr, packet, DROP_NO_ROUTE, oif);
  }
}

void Ipv6L3Protocol::Receive (Ptr<NetDevice> device, Ptr<const Packet> p, uint16_t protocol, const Address &from, const Address &to, NetDevice::PacketType packetType)
{
  NS_LOG_FUNCTION (this << device << p << protocol << from << to << packetType);
  NS_LOG_LOGIC ("Packet from " << from << " received on node " << m_node->GetId ());
  uint32_t interface = 0;
  Ptr<Packet> packet = p->Copy ();
  Ptr<Ipv6Interface> ipv6Interface = 0;
  
  for (Ipv6InterfaceList::const_iterator it = m_interfaces.begin () ; it != m_interfaces.end () ; it++)
  {
    ipv6Interface = *it;

    if (ipv6Interface->GetDevice () == device)
    {
      if (ipv6Interface->IsUp ())
      {
        m_rxTrace (packet, interface);
        break;
      }
      else
      {
        NS_LOG_LOGIC ("Dropping received packet-- interface is down");
        Ipv6Header hdr;
        packet->RemoveHeader (hdr);
        m_dropTrace (hdr, packet, DROP_INTERFACE_DOWN, interface);
        return;
      }
    }
    interface++;
  }

  Ipv6Header hdr;
  packet->RemoveHeader (hdr);

  /* forward up to IPv6 raw sockets */
  for (SocketList::iterator it = m_sockets.begin () ; it != m_sockets.end () ; ++it)
  {
    Ptr<Ipv6RawSocketImpl> socket = *it;
    socket->ForwardUp (packet, hdr, device);
  }

  m_routingProtocol->RouteInput (packet, hdr, device,
    MakeCallback (&Ipv6L3Protocol::IpForward, this),
    MakeCallback (&Ipv6L3Protocol::IpMulticastForward, this),
    MakeCallback (&Ipv6L3Protocol::LocalDeliver, this),
    MakeCallback (&Ipv6L3Protocol::RouteInputError, this)
  );
}

void Ipv6L3Protocol::SendRealOut (Ptr<Ipv6Route> route, Ptr<Packet> packet, Ipv6Header const& ipHeader)
{
  NS_LOG_FUNCTION (this << route << packet << ipHeader);

  if (!route)
  {
    NS_LOG_LOGIC ("No route to host, drop!.");
    return;
  }

  Ptr<NetDevice> dev = route->GetOutputDevice ();
  int32_t interface = GetInterfaceForDevice (dev);
  NS_ASSERT (interface >= 0);
  
  Ptr<Ipv6Interface> outInterface = GetInterface (interface);
  NS_LOG_LOGIC ("Send via NetDevice ifIndex " << dev->GetIfIndex () << " Ipv6InterfaceIndex " << interface);

  if (!route->GetGateway ().IsEqual (Ipv6Address::GetAny ()))
  {
    if (outInterface->IsUp ())
    {
      NS_LOG_LOGIC ("Send to gateway " << route->GetGateway ());
      packet->AddHeader (ipHeader);
      NS_ASSERT (packet->GetSize () <= outInterface->GetDevice ()->GetMtu ());
      m_txTrace (packet, interface);
      outInterface->Send (packet, route->GetGateway ());
    }
    else
    {
      NS_LOG_LOGIC ("Dropping-- outgoing interface is down: " << route->GetGateway ());
      m_dropTrace (ipHeader, packet, DROP_INTERFACE_DOWN, interface);
    }
  }
  else
  {
    if (outInterface->IsUp ())
    {
       NS_LOG_LOGIC ("Send to destination " << ipHeader.GetDestinationAddress ());
       packet->AddHeader (ipHeader);
       NS_ASSERT (packet->GetSize () <= outInterface->GetDevice ()->GetMtu ());
       m_txTrace (packet, interface);
       outInterface->Send (packet, ipHeader.GetDestinationAddress ());
    }
    else
    {
      NS_LOG_LOGIC ("Dropping-- outgoing interface is down: " << ipHeader.GetDestinationAddress ());
      m_dropTrace (ipHeader, packet, DROP_INTERFACE_DOWN, interface);
    }
  }
}

void Ipv6L3Protocol::IpForward (Ptr<Ipv6Route> rtentry, Ptr<const Packet> p, const Ipv6Header& header)
{
  NS_LOG_FUNCTION (this << rtentry << p << header);
  NS_LOG_LOGIC ("Forwarding logic for node: " << m_node->GetId ());
  
  // Forwarding
  Ipv6Header ipHeader = header;
  Ptr<Packet> packet = p->Copy ();
  ipHeader.SetHopLimit (ipHeader.GetHopLimit () - 1);

  if (ipHeader.GetSourceAddress ().IsLinkLocal ())
  {
    /* no forward for link-local address */
    return;
  }
  
  if (ipHeader.GetHopLimit () == 0)
  {
    NS_LOG_WARN ("TTL exceeded.  Drop.");
    m_dropTrace (ipHeader, packet, DROP_TTL_EXPIRED, 0);
    // Do not reply to ICMPv6 or to multicast IPv6 address
    if (ipHeader.GetNextHeader () != Icmpv6L4Protocol::PROT_NUMBER &&
        ipHeader.GetDestinationAddress ().IsMulticast () == false)
    {
      packet->AddHeader (ipHeader);
      GetIcmpv6 ()->SendErrorTimeExceeded (packet, ipHeader.GetSourceAddress (), Icmpv6Header::ICMPV6_HOPLIMIT);
    }
    return;
  }

  /* ICMPv6 Redirect */

  /* if we forward to a machine on the same network as the source, 
   * we send him an ICMPv6 redirect message to notify him that a short route 
   * exists.
   */
  if ((!rtentry->GetGateway ().IsAny () && rtentry->GetGateway ().CombinePrefix (Ipv6Prefix (64)) == header.GetSourceAddress ().CombinePrefix (Ipv6Prefix (64))) ||
      (rtentry->GetDestination ().CombinePrefix (Ipv6Prefix (64)) == header.GetSourceAddress ().CombinePrefix (Ipv6Prefix (64))))
  {
    NS_LOG_LOGIC ("ICMPv6 redirect!");
    Ptr<Icmpv6L4Protocol> icmpv6 = GetIcmpv6 ();
    Address hardwareTarget;
    Ipv6Address dst = header.GetDestinationAddress ();
    Ipv6Address src = header.GetSourceAddress ();
    Ipv6Address target = rtentry->GetGateway ();
    Ptr<Packet> copy = p->Copy ();

    if (target.IsAny ())
    {
      target = dst;
    }

    copy->AddHeader (header);
    
    if (icmpv6->Lookup (target, rtentry->GetOutputDevice (), 0, &hardwareTarget))
    {
      icmpv6->SendRedirection (copy, src, target, dst, hardwareTarget);
    }
    else
    {
      icmpv6->SendRedirection (copy, src, target, dst, Address ());
    }
  }
  
  SendRealOut (rtentry, packet, ipHeader);
}

void Ipv6L3Protocol::IpMulticastForward (Ptr<Ipv6MulticastRoute> mrtentry, Ptr<const Packet> p, const Ipv6Header& header)
{
  NS_LOG_FUNCTION (this << mrtentry << p << header);
  NS_LOG_LOGIC ("Multicast forwarding logic for node: " << m_node->GetId ());

  // The output interfaces we could forward this onto are encoded
  // in the OutputTtl of the Ipv6MulticastRoute
  for (uint32_t i = 0 ; i < Ipv6MulticastRoute::MAX_INTERFACES ; i++)
  {
    if (mrtentry->GetOutputTtl (i) < Ipv6MulticastRoute::MAX_TTL)
    {
      Ptr<Packet> packet = p->Copy ();
      Ipv6Header h = header;
      h.SetHopLimit (header.GetHopLimit () - 1);
      if (h.GetHopLimit () == 0)
      {
        NS_LOG_WARN ("TTL exceeded.  Drop.");
        m_dropTrace (header, packet, DROP_TTL_EXPIRED, i);
        return;
      }

      NS_LOG_LOGIC ("Forward multicast via interface " << i);
      Ptr<Ipv6Route> rtentry = Create<Ipv6Route> ();
      rtentry->SetSource (h.GetSourceAddress ());
      rtentry->SetDestination (h.GetDestinationAddress ());
      rtentry->SetGateway (Ipv6Address::GetAny ());
      rtentry->SetOutputDevice (GetNetDevice (i));
      SendRealOut (rtentry, packet, h);
      return;
    }
  }
}

void Ipv6L3Protocol::LocalDeliver (Ptr<const Packet> packet, Ipv6Header const& ip, uint32_t iif)
{
  NS_LOG_FUNCTION (this << packet << ip << iif);
  Ptr<Packet> p = packet->Copy ();
  Ptr<Ipv6L4Protocol> protocol = GetProtocol (ip.GetNextHeader ());

  if (protocol)
  {
    Ptr<Packet> copy = p->Copy ();
    enum Ipv6L4Protocol::RxStatus_e status = protocol->Receive (p, ip.GetSourceAddress (), ip.GetDestinationAddress (), GetInterface (iif));

    switch (status)
    {
    case Ipv6L4Protocol::RX_OK:
      break;
    case Ipv6L4Protocol::RX_CSUM_FAILED:
      break;
    case Ipv6L4Protocol::RX_ENDPOINT_UNREACH:
      if (ip.GetDestinationAddress ().IsMulticast ())
      {
        /* do not rely on multicast address */
        break;
      }

      copy->AddHeader (ip);
      GetIcmpv6 ()->SendErrorDestinationUnreachable (copy, ip.GetSourceAddress (), Icmpv6Header::ICMPV6_PORT_UNREACHABLE);
    }
  }
}

void Ipv6L3Protocol::RouteInputError (Ptr<const Packet> p, const Ipv6Header& ipHeader, Socket::SocketErrno sockErrno)
{
  NS_LOG_FUNCTION (this << p << ipHeader << sockErrno);
  NS_LOG_LOGIC ("Route input failure-- dropping packet to " << ipHeader << " with errno " << sockErrno);
  m_dropTrace (ipHeader, p, DROP_ROUTE_ERROR, 0);
}

Ipv6Header Ipv6L3Protocol::BuildHeader (Ipv6Address src, Ipv6Address dst, uint8_t protocol, uint16_t payloadSize, uint8_t ttl)
{
  NS_LOG_FUNCTION (this << src << dst << (uint32_t)protocol << (uint32_t)payloadSize << (uint32_t)ttl);
  Ipv6Header hdr;

  hdr.SetSourceAddress (src);
  hdr.SetDestinationAddress (dst);
  hdr.SetNextHeader (protocol);
  hdr.SetPayloadLength (payloadSize);
  hdr.SetHopLimit (ttl);
  return hdr;
}

} /* namespace ns3 */