// -*- 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>

//         Gustavo Carneiro <gjc@inescporto.pt>

//

#ifndef IPV4_STATIC_ROUTING_H

#define IPV4_STATIC_ROUTING_H

#include <list>

#include <stdint.h>

#include "ns3/ipv4-address.h"

#include "ipv4-header.h"

#include "ns3/ptr.h"

#include "ns3/ipv4.h"

namespace ns3 {

class Packet;

class NetDevice;

class Ipv4Interface;

class Ipv4Address;

class Ipv4Header;

class Ipv4Route;

class Node;

/**

 * @brief Static routing protocol for IP version 4 stacks.

 *

 * In ns-3 we have the concept of a pluggable routing protocol.  Routing

 * protocols are added to a list maintained by the Ipv4L3Protocol.  Every 

 * stack gets one routing protocol for free -- the Ipv4StaticRouting routing

 * protocol is added in the constructor of the Ipv4L3Protocol (this is the 

 * piece of code that implements the functionality of the IP layer).

 *

 * The Ipv4StaticRouting class inherits from the abstract base class 

 * Ipv4RoutingProtocol that defines the interface methods that a routing 

 * protocol must support.

 *

 * When a packet arrives in the Ipv4L3Protocol for transmission, it comes

 * either from a local source via Ipv4L3Protocol::Send or from a remote 

 * source via Ipv4L3Protocol::Forwarding.  In both cases, a function is called

 * (Ipv4L3Protocol::Lookup) to look up the routing information for the packet.

 *

 * The lookup function iterates through the list of routing protocols asking

 * each to see if it can find a route and send the packet.  A callback is 

 * provided during each of these calls that should be considered a pre-

 * packaged send call.  This is done to allow asynchronous calls into 

 * routing subsystems in order to support on-demand routing, for example.  The

 * method for requesting this operation is Ipv4StaticRouting::RequestRoute for

 * the static routing protocol.

 *

 * Each routing protocol is also free to implement its own methods for managing

 * routes which you will find below.  This class manages a set of "static" or

 * manually configured routes for host, network and multicast routes.

 *

 * @see Ipv4RoutingProtocol

 * @see Ipv4L3Protocol::AddRoutingProtocol

 * @see Ipv4L3Protocol::Ipv4L3Protocol

 */

class Ipv4StaticRouting : public Ipv4RoutingProtocol

{

public:

/**

 * @brief Construct an empty Ipv4StaticRouting routing protocol,

 * @internal

 *

 * The Ipv4StaticRouting class supports host, network and multicast routes.

 * This method initializes the lists containing these routes to empty.

 *

 * @see Ipv4StaticRouting

 */

  Ipv4StaticRouting ();

/**

 * @brief Request that a check for a route bw performed and if a route is found

 * that the packet be sent on its way using the pre-packaged send callback.

 *

 * The source and destination IP addresses for the packet in question are found

 * in the provided Ipv4Header.  There are two major processing forks depending

 * on the type of destination address.  

 *

 * If the destination address is unicast then the routing table is consulted 

 * for a route to the destination and if it is found, the routeReply callback

 * is executed to send the packet (with the found route).

 * 

 * If the destination address is a multicast, then the exact processing steps

 * depend on whether or not the packet has been sourced locally.  This is 

 * determined by the parameter ifIndex.  This is the interface index over which

 * this packet was received.  If the packet has not been received over a

 * network interface, this index will be set to 

 * Ipv4RoutingProtocol::IF_INDEX_ANY (a very large number).  In that case, 

 * we want to avoid the requirement that an explicit route out of each node 

 * must be set, so we don't do anything here.

 * 

 * If the packet is a multicast destination and has been received over a 

 * network interface, a call to this method implies that the packet is being

 * forwarded.  In that case, there must be an explicit route out of the node.

 * A multicast route references the source address, the destination address

 * (the multicast group) and the input interface in order to find a route.

 * We consult the multicast routing table and, if a route is found, send the

 * packet out of as many interfaces as required using the provided callback

 * (think of it as a pre-packaged send call).

 *

 * @param ifIndex The network interface index over which the packed was 

 * received.  If the packet is from a local source, ifIndex will be set to

 * Ipv4RoutingProtocol::IF_INDEX_ANY.

 * @param ipHeader the Ipv4Header containing the source and destination IP

 * addresses for the packet.

 * @param packet The packet to be sent if a route is found.

 * @param routeReply A callback that packaged up the call to actually send the

 * packet.

 * @return Returns true if a route is found and the packet has been sent,

 * otherwise returns false indicating that the next routing protocol should

 * be consulted.  In practice, the static routing protocol is the last chance

 * protocol.

 *

 * @see Ipv4StaticRouting

 * @see Ipv4RoutingProtocol

 */

  virtual bool RequestRoute (uint32_t ifIndex,

                             Ipv4Header const &ipHeader,

                             Ptr<Packet> packet,

                             RouteReplyCallback routeReply);

/**

 * @brief Check to see if we can determine the interface index that will be

 * used if a packet is sent to this destination.

 *

 * This method addresses a problem in the IP stack where a destination address

 * must be present and checksummed into the IP header before the actual 

 * interface over which the packet is sent can be determined.  The answer is

 * to implement a known and intentional cross-layer violation.  This is the

 * endpoint of a call chain that started up quite high in the stack (sockets)

 * and has found its way down to the Ipv4L3Protocol which is consulting the

 * routing protocols for what they would do if presented with a packet of the

 * given destination.

 *

 * Note that the a single interface index is returned.  This means that if

 * the destination address is a multicast, and an explicit route is present

 * that includeds multiple output interfaces, that route cannot be used.

 * 

 * If there are multiple paths out of the node, the resolution is performed

 * by Ipv4L3Protocol::GetIfIndexforDestination which has access to more 

 * contextual information that is useful for making a determination.

 *

 * @param destination The Ipv4Address if the destination of a hypothetical 

 * packet.  This may be a multicast group address.

 * @param ifIndex A reference to the interface index over which a packet

 * sent to this destination would be sent.

 * @return Returns true if a route is found to the destination that involves

 * a single output interface index, otherwise returns false indicating that

 * the next routing protocol should be consulted.  In practice, the static 

 * routing protocol is the last chance protocol.

 *

 * @see Ipv4StaticRouting

 * @see Ipv4RoutingProtocol

 * @see Ipv4L3Protocol

 */

  virtual bool RequestIfIndex (Ipv4Address destination, uint32_t& ifIndex);

/**

 * @brief Add a host route to the static routing table.

 *

 * @param dest The Ipv4Address destination for this route.

 * @param nextHop The Ipv4Address of the next hop in the route.

 * @param interface The network interface index used to send packets to the

 * destination.

 *

 * @see Ipv4Address

 */

  void AddHostRouteTo (Ipv4Address dest, 

                       Ipv4Address nextHop, 

                       uint32_t interface);

/**

 * @brief Add a host route to the static routing table.

 *

 * @param dest The Ipv4Address destination for this route.

 * @param interface The network interface index used to send packets to the

 * destination.

 *

 * @see Ipv4Address

 */

  void AddHostRouteTo (Ipv4Address dest, 

                       uint32_t interface);

/**

 * @brief Add a network route to the static routing table.

 *

 * @param network The Ipv4Address network for this route.

 * @param networkMask The Ipv4Mask to extract the network.

 * @param nextHop The next hop in the route to the destination network.

 * @param interface The network interface index used to send packets to the

 * destination.

 *

 * @see Ipv4Address

 */

  void AddNetworkRouteTo (Ipv4Address network, 

                          Ipv4Mask networkMask, 

                          Ipv4Address nextHop, 

                          uint32_t interface);

/**

 * @brief Add a network route to the static routing table.

 *

 * @param network The Ipv4Address network for this route.

 * @param networkMask The Ipv4Mask to extract the network.

 * @param interface The network interface index used to send packets to the

 * destination.

 *

 * @see Ipv4Address

 */

  void AddNetworkRouteTo (Ipv4Address network, 

                          Ipv4Mask networkMask, 

                          uint32_t interface);

/**

 * @brief Add a default route to the static routing table.

 *

 * This method tells the routing system what to do in the case where a specific

 * route to a destination is not found.  The system forwards packets to the

 * specified node in the hope that it knows better how to route the packet.

 * 

 * If the default route is set, it is returned as the selected route from 

 * LookupStatic irrespective of destination address if no specific route is

 * found.

 *

 * @param nextHop The Ipv4Address to send packets to in the hope that they

 * will be forwarded correctly.

 * @param interface The network interface index used to send packets.

 *

 * @see Ipv4Address

 * @see Ipv4StaticRouting::Lookup

 */

  void SetDefaultRoute (Ipv4Address nextHop, 

                        uint32_t interface);

/**

 * @brief Get the number of individual unicast routes that have been added

 * to the routing table.

 *

 * @warning The default route counts as one of the routes.

 */

  uint32_t GetNRoutes (void);

/**

 * @brief Get the default route from the static routing table.

 *

 * @return If the default route is set, a pointer to that Ipv4Route is

 * returned, otherwise a zero pointer is returned.

 *

 * @see Ipv4Route

 */

  Ipv4Route *GetDefaultRoute (void);

/**

 * @brief Get a route from the static unicast routing table.

 *

 * Externally, the unicast static routing table appears simply as a table with

 * n entries.  The one sublety of note is that if a default route has been set

 * it will appear as the zeroth entry in the table.  This means that if you

 * add only a default route, the table will have one entry that can be accessed

 * either by explicity calling GetDefaultRoute () or by calling GetRoute (0).

 * 

 * Similarly, if the default route has been set, calling RemoveRoute (0) will

 * remove the default route.

 *

 * @param i The index (into the routing table) of the route to retrieve.  If

 * the default route has been set, it will occupy index zero.

 * @return If route is set, a pointer to that Ipv4Route is returned, otherwise

 * a zero pointer is returned.

 *

 * @see Ipv4Route

 * @see Ipv4StaticRouting::RemoveRoute

 */

  Ipv4Route *GetRoute (uint32_t i);

/**

 * @brief Remove a route from the static unicast routing table.

 *

 * Externally, the unicast static routing table appears simply as a table with

 * n entries.  The one sublety of note is that if a default route has been set

 * it will appear as the zeroth entry in the table.  This means that if the

 * default route has been set, calling RemoveRoute (0) will remove the

 * default route.

 *

 * @param i The index (into the routing table) of the route to remove.  If

 * the default route has been set, it will occupy index zero.

 *

 * @see Ipv4Route

 * @see Ipv4StaticRouting::GetRoute

 * @see Ipv4StaticRouting::AddRoute

 */

  void RemoveRoute (uint32_t i);

/**

 * @brief Add a multicast route to the static routing table.

 *

 * A multicast route must specify an origin IP address, a multicast group and

 * an input network interface index as conditions and provide a vector of

 * output network interface indices over which packets matching the conditions

 * are sent.

 *

 * Typically there are two main types of multicast routes:  routes of the 

 * first kind are used during forwarding.  All of the conditions must be

 * exlicitly provided.  The second kind of routes are used to get packets off

 * of a local node.  The difference is in the input interface.  Routes for

 * forwarding will always have an explicit input interface specified.  Routes

 * off of a node will always set the input interface to a wildcard specified

 * by the index Ipv4RoutingProtocol::IF_INDEX_ANY.

 *

 * For routes off of a local node wildcards may be used in the origin and

 * multicast group addresses.  The wildcard used for Ipv4Adresses is that 

 * address returned by Ipv4Address::GetAny () -- typically "0.0.0.0".  Usage

 * of a wildcard allows one to specify default behavior to varying degrees.

 *

 * For example, making the origin address a wildcard, but leaving the 

 * multicast group specific allows one (in the case of a node with multiple

 * interfaces) to create different routes using different output interfaces

 * for each multicast group.

 *

 * If the origin and multicast addresses are made wildcards, you have created

 * essentially a default multicast address that can forward to multiple 

 * interfaces.  Compare this to the actual default multicast address that is

 * limited to specifying a single output interface for compatibility with

 * existing functionality in other systems.

 * 

 * @param origin The Ipv4Address of the origin of packets for this route.  May

 * be Ipv4Address:GetAny for open groups.

 * @param group The Ipv4Address of the multicast group or this route.

 * @param inputInterface The input network interface index over which to 

 * expect packets destined for this route.  May be

 * Ipv4RoutingProtocol::IF_INDEX_ANY for packets of local origin.

 * @param outputInterfaces A vector of network interface indices used to specify

 * how to send packets to the destination(s).

 *

 * @see Ipv4Address

 */

  void AddMulticastRoute (Ipv4Address origin,

                          Ipv4Address group,

                          uint32_t inputInterface,

                          std::vector<uint32_t> outputInterfaces);

/**

 * @brief Add a default multicast route to the static routing table.

 *

 * This is the multicast equivalent of the unicast version SetDefaultRoute.

 * We tell the routing system what to do in the case where a specific route

 * to a destination multicast group is not found.  The system forwards 

 * packets out the specified interface in the hope that "something out there"

 * knows better how to route the packet.  This method is only used in 

 * initially sending packets off of a host.  The default multicast route is

 * not consulted during forwarding -- exact routes must be specified using

 * AddMulticastRoute for that case.

 *

 * Since we're basically sending packets to some entity we think may know

 * better what to do, we don't pay attention to "subtleties" like origin

 * address, nor do we worry about forwarding out multiple  interfaces.  If the

 * default multicast route is set, it is returned as the selected route from 

 * LookupStatic irrespective of origin or multicast group if another specific

 * route is not found.

 *

 * @param outputInterface The network interface index used to specify where

 * to send packets in the case of unknown routes.

 *

 * @see Ipv4Address

 */

  void SetDefaultMulticastRoute (uint32_t outputInterface);

/**

 * @brief Get the number of individual multicast routes that have been added

 * to the routing table.

 *

 * @warning The default multicast route counts as one of the routes.

 */

  uint32_t GetNMulticastRoutes (void) const;

/**

 * @brief Get a route from the static multicast routing table.

 *

 * Externally, the multicast static routing table appears simply as a table 

 * with n entries.  The one sublety of note is that if a default route has 

 * been set it will appear as the zeroth entry in the table.  This means that 

 * if you add only a default route, the table will have one entry that can be

 * accessed either by explicity calling GetDefaultMulticastRoute () or by

 * calling GetMulticastRoute (0).

 * 

 * Similarly, if the default route has been set, calling 

 * RemoveMulticastRoute (0) will remove the default route.

 *

 * @param i The index (into the routing table) of the multicast route to

 * retrieve.  If the default route has been set, it will occupy index zero.

 * @return If route \e i is set, a pointer to that Ipv4MulticastRoute is

 * returned, otherwise a zero pointer is returned.

 *

 * @see Ipv4MulticastRoute

 * @see Ipv4StaticRouting::RemoveRoute

 */

  Ipv4MulticastRoute *GetMulticastRoute (uint32_t i) const;

/**

 * @brief Get the default multicast route from the static routing table.

 *

 * @return If the default route is set, a pointer to that Ipv4MulticastRoute is

 * returned, otherwise a zero pointer is returned.

 *

 * @see Ipv4Route

 */

  Ipv4MulticastRoute *GetDefaultMulticastRoute (void) const;

/**

 * @brief Remove a route from the static multicast routing table.

 *

 * Externally, the multicast static routing table appears simply as a table 

 * with n entries.  The one sublety of note is that if a default multicast

 * route has been set it will appear as the zeroth entry in the table.  This

 * means that the default route may be removed by calling this method with

 * appropriate wildcard parameters.

 *

 * This method causes the multicast routing table to be searched for the first

 * route that matches the parameters and removes it.

 *

 * Wildcards may be provided to this function, but the wildcards are used to

 * exacly match wildcards in the routes (see AddMulticastRoute).  That is,

 * calling RemoveMulticastRoute with the origin set to "0.0.0.0" will not

 * remove routes with any address in the origin, but will only remove routes

 * with "0.0.0.0" set as the the origin.

 *

 * @param origin The IP address specified as the origin of packets for the

 * route.

 * @param group The IP address specified as the multicast group addres of

 * the route.

 * @param inputInterface The network interface index specified as the expected

 * input interface for the route.

 * @returns true if a route was found and removed, false otherwise.

 *

 * @see Ipv4MulticastRoute

 * @see Ipv4StaticRouting::AddMulticastRoute

 */

  bool RemoveMulticastRoute (Ipv4Address origin,

                             Ipv4Address group,

                             uint32_t inputInterface);

/**

 * @brief Remove a route from the static multicast routing table.

 *

 * Externally, the multicast static routing table appears simply as a table 

 * with n entries.  The one sublety of note is that if a default multicast

 * route has been set it will appear as the zeroth entry in the table.  This 

 * means that if the default route has been set, calling 

 * RemoveMulticastRoute (0) will remove the default route.

 *

 * @param index The index (into the multicast routing table) of the route to

 * remove.  If the default route has been set, it will occupy index zero.

 *

 * @see Ipv4Route

 * @see Ipv4StaticRouting::GetRoute

 * @see Ipv4StaticRouting::AddRoute

 */

  void RemoveMulticastRoute (uint32_t index);

protected:

  void DoDispose (void);

private:

  typedef std::list<Ipv4Route *> HostRoutes;

  typedef std::list<Ipv4Route *>::const_iterator HostRoutesCI;

  typedef std::list<Ipv4Route *>::iterator HostRoutesI;

  typedef std::list<Ipv4Route *> NetworkRoutes;

  typedef std::list<Ipv4Route *>::const_iterator NetworkRoutesCI;

  typedef std::list<Ipv4Route *>::iterator NetworkRoutesI;

  typedef std::list<Ipv4MulticastRoute *> MulticastRoutes;

  typedef std::list<Ipv4MulticastRoute *>::const_iterator MulticastRoutesCI;

  typedef std::list<Ipv4MulticastRoute *>::iterator MulticastRoutesI;

  Ipv4Route *LookupStatic (Ipv4Address dest);

  Ipv4MulticastRoute *LookupStatic (Ipv4Address origin, Ipv4Address group,

                                    uint32_t ifIndex);