/*
 * Copyright (c) 2007 INRIA
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 */

/* taken from src/node/ipv4.h and adapted to IPv6 */

#ifndef IPV6_H
#define IPV6_H

#include "ipv6-interface-address.h"

#include "ns3/callback.h"
#include "ns3/ipv6-address.h"
#include "ns3/object.h"
#include "ns3/socket.h"

#include <stdint.h>

namespace ns3
{

class Node;
class NetDevice;
class Packet;
class Ipv6RoutingProtocol;
class IpL4Protocol;
class Ipv6Route;

/**
 * @ingroup internet
 * @defgroup ipv6 IPv6 classes and sub-modules
 */

/**
 * @ingroup ipv6
 * @brief Access to the IPv6 forwarding table, interfaces, and configuration
 *
 * This class defines the API to manipulate the following aspects of
 * the IPv6 implementation:
 * -# set/get an Ipv6RoutingProtocol
 * -# register a NetDevice for use by the IPv6 layer (basically, to
 * create IPv6-related state such as addressing and neighbor cache that
 * is associated with a NetDevice)
 * -# manipulate the status of the NetDevice from the IPv6 perspective,
 * such as marking it as Up or Down,
 * -# adding, deleting, and getting addresses associated to the IPv6
 * interfaces.
 * -# exporting IPv6 configuration attributes
 *
 * Each NetDevice has conceptually a single IPv6 interface associated
 * with it (the corresponding structure in the Linux IPv6 implementation
 * is struct in_device).  Each interface may have one or more IPv6
 * addresses associated with it.  Each IPv6 address may have different
 * subnet mask, scope, etc., so all of this per-address information
 * is stored in an Ipv6InterfaceAddress class (the corresponding
 * structure in Linux is struct in6_ifaddr)
 *
 * IPv6 attributes such as whether IP forwarding is enabled and disabled
 * are also stored in this class
 *
 * TO DO:  Add API to allow access to the IPv6 neighbor table
 *
 * @see Ipv6RoutingProtocol
 * @see Ipv6InterfaceAddress
 */
class Ipv6 : public Object
{
  public:
    /**
     * @brief Get the type ID.
     * @return the object TypeId
     */
    static TypeId GetTypeId();

    /**
     * @brief Constructor.
     */
    Ipv6();

    /**
     * @brief Destructor.
     */
    ~Ipv6() override;

    /**
     * @brief Register a new routing protocol to be used by this IPv6 stack
     *
     * This call will replace any routing protocol that has been previously
     * registered.  If you want to add multiple routing protocols, you must
     * add them to a Ipv6ListRoutingProtocol directly.
     *
     * @param routingProtocol smart pointer to Ipv6RoutingProtocol object
     */
    virtual void SetRoutingProtocol(Ptr<Ipv6RoutingProtocol> routingProtocol) = 0;

    /**
     * @brief Get the routing protocol to be used by this IPv6 stack
     *
     * @returns smart pointer to Ipv6RoutingProtocol object, or null pointer if none
     */
    virtual Ptr<Ipv6RoutingProtocol> GetRoutingProtocol() const = 0;

    /**
     * @brief Add a NetDevice interface.
     *
     * Once a device has been added, it can never be removed: if you want
     * to disable it, you can invoke Ipv6::SetDown which will
     * make sure that it is never used during packet forwarding.
     * @param device device to add to the list of IPv6 interfaces
     *        which can be used as output interfaces during packet forwarding.
     * @returns the index of the IPv6 interface added.
     */
    virtual uint32_t AddInterface(Ptr<NetDevice> device) = 0;

    /**
     * @brief Get number of interfaces.
     * @returns the number of interfaces added by the user.
     */
    virtual uint32_t GetNInterfaces() const = 0;

    /**
     * @brief Return the interface number of the interface that has been
     *        assigned the specified IP address.
     *
     * @param address The IP address being searched for
     * @returns The interface number of the IPv6 interface with the given
     *          address or -1 if not found.
     *
     * Each IP interface has one or more IP addresses associated with it.
     * This method searches the list of interfaces for one that holds a
     * particular address.  This call takes an IP address as a parameter and
     * returns the interface number of the first interface that has been assigned
     * that address, or -1 if not found.  There must be an exact match.
     */
    virtual int32_t GetInterfaceForAddress(Ipv6Address address) const = 0;

    /**
     * @brief Return the interface number of first interface found that
     *  has an IPv6 address within the prefix specified by the input
     *  address and mask parameters
     *
     * @param address The IP address assigned to the interface of interest.
     * @param mask The IP prefix to use in the mask
     * @returns The interface number of the IPv6 interface with the given
     *          address or -1 if not found.
     *
     * Each IP interface has one or more IP addresses associated with it.
     * This method searches the list of interfaces for the first one found
     * that holds an address that is included within the prefix
     * formed by the input address and mask parameters.  The value -1 is
     * returned if no match is found.
     */
    virtual int32_t GetInterfaceForPrefix(Ipv6Address address, Ipv6Prefix mask) const = 0;

    /**
     * @brief Get the NetDevice of the specified interface number.
     * @param interface The interface number of an IPv6 interface.
     * @returns The NetDevice associated with the IPv6 interface number.
     */
    virtual Ptr<NetDevice> GetNetDevice(uint32_t interface) = 0;

    /**
     * @brief Get the interface index of the specified NetDevice.
     * @param device The NetDevice for an Ipv6Interface
     * @returns The interface number of an IPv6 interface or -1 if not found.
     */
    virtual int32_t GetInterfaceForDevice(Ptr<const NetDevice> device) const = 0;

    /**
     * @brief Add an address on the specified IPv6 interface.
     * @param interface Interface number of an IPv6 interface
     * @param address Ipv6InterfaceAddress address to associate with the underlying IPv6 interface
     * @param addOnLinkRoute add on-link route to the network (default true)
     * @returns true if the operation succeeded
     */
    virtual bool AddAddress(uint32_t interface,
                            Ipv6InterfaceAddress address,
                            bool addOnLinkRoute = true) = 0;

    /**
     * @brief Get number of addresses on specified IPv6 interface.
     * @param interface Interface number of an IPv6 interface
     * @returns the number of Ipv6InterfaceAddress entries for the interface.
     */
    virtual uint32_t GetNAddresses(uint32_t interface) const = 0;

    /**
     * @brief Get IPv6 address on specified IPv6 interface.
     *
     * Because addresses can be removed, the addressIndex is not guaranteed
     * to be static across calls to this method.
     *
     * @param interface Interface number of an IPv6 interface
     * @param addressIndex index of Ipv6InterfaceAddress
     * @returns the Ipv6InterfaceAddress associated to the interface and addressIndex
     */
    virtual Ipv6InterfaceAddress GetAddress(uint32_t interface, uint32_t addressIndex) const = 0;

    /**
     * @brief Remove an address on specified IPv6 interface.
     *
     * Remove the address at addressIndex on named interface.  The addressIndex
     * for all higher indices will decrement by one after this method is called;
     * so, for example, to remove 5 addresses from an interface i, one could
     * call RemoveAddress (i, 0); 5 times.
     *
     * @param interface Interface number of an IPv6 interface
     * @param addressIndex index of Ipv6InterfaceAddress to remove
     * @returns true if the operation succeeded
     */
    virtual bool RemoveAddress(uint32_t interface, uint32_t addressIndex) = 0;

    /**
     * @brief Remove the given address on named Ipv6 interface
     *
     * @param interface Interface number of an IPv6 interface
     * @param address the address to remove
     * @returns true if the operation succeeded
     */
    virtual bool RemoveAddress(uint32_t interface, Ipv6Address address) = 0;

    /**
     * @brief Set metric on specified Ipv6 interface.
     *
     * @param interface The interface number of an IPv6 interface
     * @param metric routing metric (cost) associated to the underlying
     *          IPv6 interface
     */
    virtual void SetMetric(uint32_t interface, uint16_t metric) = 0;

    /**
     * @brief Get metric for the specified IPv6 interface.
     *
     * @param interface The interface number of an IPv6 interface
     * @returns routing metric (cost) associated to the underlying
     *          IPv6 interface
     */
    virtual uint16_t GetMetric(uint32_t interface) const = 0;

    /**
     * @brief Get MTU for the specified IPv6 interface.
     * @param interface Interface number of IPv6 interface
     * @returns the Maximum Transmission Unit (in bytes) associated
     *          to the underlying IPv6 interface
     */
    virtual uint16_t GetMtu(uint32_t interface) const = 0;

    /**
     * @brief Set the Path MTU for the specified IPv6 destination address.
     * @param dst Ipv6 destination address
     * @param pmtu the Path MTU
     */
    virtual void SetPmtu(Ipv6Address dst, uint32_t pmtu) = 0;

    /**
     * @brief If the specified interface index is in "up" state.
     * @param interface Interface number of IPv6 interface
     * @returns true if the underlying interface is in the "up" state,
     *          false otherwise.
     */
    virtual bool IsUp(uint32_t interface) const = 0;

    /**
     * @brief Set the interface into the "up" state.
     *
     * In this state, it is considered valid during IPv6 forwarding.
     * @param interface Interface number of IPv6 interface
     */
    virtual void SetUp(uint32_t interface) = 0;

    /**
     * @brief Set the interface into the "down" state.
     *
     * In this state, it is ignored during IPv6 forwarding.
     * @param interface Interface number of IPv6 interface
     */
    virtual void SetDown(uint32_t interface) = 0;

    /**
     * @brief If the specified IPv6 interface has forwarding enabled.
     * @param interface Interface number of IPv6 interface
     * @returns true if IPv6 forwarding enabled for input datagrams on this device
     */
    virtual bool IsForwarding(uint32_t interface) const = 0;

    /**
     * @brief Set forwarding on specified IPv6 interface.
     * @param interface Interface number of IPv6 interface
     * @param val Value to set the forwarding flag
     *
     * If set to true, IPv6 forwarding is enabled for input datagrams on this device
     */
    virtual void SetForwarding(uint32_t interface, bool val) = 0;

    /**
     * @brief Choose the source address to use with destination address.
     * @param interface interface index
     * @param dest IPv6 destination address
     * @return IPv6 source address to use
     */
    virtual Ipv6Address SourceAddressSelection(uint32_t interface, Ipv6Address dest) = 0;

    /**
     * @brief Add a L4 protocol.
     * @param protocol L4 protocol
     */
    virtual void Insert(Ptr<IpL4Protocol> protocol) = 0;

    /**
     * @brief Add a L4 protocol to a specific interface.
     *
     * This may be called multiple times for multiple interfaces for the same
     * protocol.  To insert for all interfaces, use the separate
     * Insert (Ptr<IpL4Protocol> protocol) method.
     *
     * Setting a protocol on a specific interface will overwrite the
     * previously bound protocol.
     *
     * @param protocol L4 protocol.
     * @param interfaceIndex interface index.
     */
    virtual void Insert(Ptr<IpL4Protocol> protocol, uint32_t interfaceIndex) = 0;

    /**
     * @brief Remove a L4 protocol.
     * @param protocol L4 protocol to remove.
     */
    virtual void Remove(Ptr<IpL4Protocol> protocol) = 0;

    /**
     * @brief Remove a L4 protocol from a specific interface.
     * @param protocol L4 protocol to remove.
     * @param interfaceIndex interface index.
     */
    virtual void Remove(Ptr<IpL4Protocol> protocol, uint32_t interfaceIndex) = 0;

    /**
     * @brief Get L4 protocol by protocol number.
     * @param protocolNumber protocol number
     * @return corresponding IpL4Protocol or 0 if not found
     */
    virtual Ptr<IpL4Protocol> GetProtocol(int protocolNumber) const = 0;

    /**
     * @brief Get L4 protocol by protocol number for the specified interface.
     * @param protocolNumber protocol number
     * @param interfaceIndex interface index, -1 means "any" interface.
     * @return corresponding IpL4Protocol or 0 if not found
     */
    virtual Ptr<IpL4Protocol> GetProtocol(int protocolNumber, int32_t interfaceIndex) const = 0;

    /**
     * @brief Higher-level layers call this method to send a packet
     * down the stack to the MAC and PHY layers. All PMTU values are
     * stored at this level, so packet size calculations should be
     * done mathematically at higher levels.
     *
     * @param packet packet to send
     * @param source source address of packet
     * @param destination address of packet
     * @param protocol number of packet
     * @param route route to take
     */
    virtual void Send(Ptr<Packet> packet,
                      Ipv6Address source,
                      Ipv6Address destination,
                      uint8_t protocol,
                      Ptr<Ipv6Route> route) = 0;

    /**
     * @brief Register the IPv6 Extensions. Does nothing if the Extensions have been already
     * registered.
     */
    virtual void RegisterExtensions() = 0;

    /**
     * @brief Register the IPv6 Options. Does nothing if the Options have been already
     * registered.
     */
    virtual void RegisterOptions() = 0;

    /**
     * @brief Any interface magic number.
     */
    static const uint32_t IF_ANY = 0xffffffff;

  private:
    // Indirect the IPv6 attributes through private pure virtual methods
    /**
     * @brief Set IPv6 forwarding state.
     * @param forward IPv6 forwarding enabled or not
     */
    virtual void SetIpForward(bool forward) = 0;

    /**
     * @brief Get IPv6 forwarding state.
     * @return forwarding state (enabled or not)
     */
    virtual bool GetIpForward() const = 0;

    /**
     * @brief Set IPv6 MTU discover state.
     * @param mtuDiscover IPv6 MTU discover enabled or not
     */
    virtual void SetMtuDiscover(bool mtuDiscover) = 0;

    /**
     * @brief Get IPv6 MTU discover state.
     * @return MTU discover state (enabled or not)
     */
    virtual bool GetMtuDiscover() const = 0;

    /**
     * @brief Set or unset the Strong End System Model
     *
     * RFC1122 term for whether host rejects datagram with a dest. address on another interface
     * @param model true for Strong End System Model
     */
    virtual void SetStrongEndSystemModel(bool model) = 0;
    /**
     * @brief Get the Strong End System Model status
     *
     * RFC1122 term for whether host rejects datagram with a dest. address on another interface
     * @returns true for Strong End System Model activated
     */
    virtual bool GetStrongEndSystemModel() const = 0;
};

} // namespace ns3

#endif /* IPV6_H */
