kea/src/lib/nsas/nameserver_address.h

// Copyright (C) 2010  Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

// $Id$

#ifndef __NAMESERVER_ADDRESS_H
#define __NAMESERVER_ADDRESS_H

#include <boost/shared_ptr.hpp>

#include "asiolink.h"
#include "nameserver_entry.h"

namespace isc {
namespace nsas {

/// \brief Empty \c NameserverEntry pointer exception
///
/// Thrown if the the \c NameservrEntry pointer in the \c boost::shared_ptr that passed
/// into \c NameserverAddress' constructor is NULL
class NullNameserverEntryPointer : public isc::Exception {
public:
    NullNameserverEntryPointer(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what)
    {}
};

/// \brief Nameserver Address
///
/// This class implements the object that returned from NSAS when the resolver
/// request an address for the name server. It contains one IOAddress object
/// that can be used by resolver. When the resolver get query back from the name
/// server, it should update the name server's RTT(Round Trip Time) with this 
/// object.

class NameserverAddress {
public:
    /// \brief Constructor
    ///
    /// The NameserverAddress object will contain one shared_ptr object that
    /// pointed to NameserverEntry which contains the address as well as it's 
    /// corresponding index. The user can update it's RTT with the index later.
    ///
    /// \param namerserver A shared_ptr that points to a NameserverEntry object
    /// the shared_ptr can avoid the NameserverEntry object being dropped while the
    /// request is processing.
    /// \param index The address's index in NameserverEntry's addresses vector
    /// \param family Address family, AF_INET or AF_INET6
    NameserverAddress(boost::shared_ptr<NameserverEntry>& nameserver, uint32_t index, short family):
        ns_(nameserver), index_(index), family_(family)
    {
        if(!ns_.get()) {
            isc_throw(NullNameserverEntryPointer, "NULL NameserverEntry pointer.");
        }
    }

    /// \brief Default Constructor
    ///
    NameserverAddress(): index_(0), family_(AF_INET)
    {
    }

    /// \brief Destructor
    ///
    /// Empty destructor.
    ~NameserverAddress()
    {
    }

    /// \brief Return address
    ///
    asiolink::IOAddress getAddress() const { 
        return ns_.get()->getAddressAtIndex(index_, family_); 
    }

    /// \brief Update Round-trip Time
    ///
    /// When the user get one request back from the name server, it should
    /// update the address's RTT.
    /// \param rtt The new Round-Trip Time
    void updateRTT(uint32_t rtt) { 
        ns_.get()->updateAddressRTTAtIndex(rtt, index_, family_); 
    }
private:

    boost::shared_ptr<NameserverEntry> ns_;  ///< Shared-pointer to NameserverEntry object
    uint32_t index_;                         ///< The address index in NameserverEntry
    short family_;                           ///< Address family AF_INET or AF_INET6
};

} // namespace nsas
} // namespace isc

#endif//__NAMESERVER_ADDRESS_H