src/inet/IPPrefix.cpp

/*
 *
 *    Copyright (c) 2020 Project CHIP Authors
 *    Copyright (c) 2013-2017 Nest Labs, Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

/**
 *    @file
 *      This file implements the concrete class
 *      <tt>Inet::IPPrefix</tt>, which comprise two member fields:
 *      a) a IP address and b) a length field. The CHIP Inet Layer
 *      uses objects of this class to represent Internet protocol
 *      address prefixes of both IPv4 and IPv6 address families.
 *
 */

#include "IPPrefix.h"
#include <core/CHIPEncoding.h>

namespace chip {
namespace Inet {

IPPrefix IPPrefix::Zero;

bool IPPrefix::IsZero() const
{
    return IPAddr.Addr[0] == 0 && IPAddr.Addr[1] == 0 && IPAddr.Addr[2] == 0 && IPAddr.Addr[3] == 0 && Length == 0;
}

bool IPPrefix::operator==(const IPPrefix & other) const
{
    return IPAddr == other.IPAddr && Length == other.Length;
}

bool IPPrefix::operator!=(const IPPrefix & other) const
{
    return IPAddr != other.IPAddr || Length != other.Length;
}

IPPrefix & IPPrefix::operator=(const IPPrefix & other)
{
    if (this != &other)
    {
        IPAddr = other.IPAddr;
        Length = other.Length;
    }

    return *this;
}

bool IPPrefix::MatchAddress(const IPAddress & addr) const
{
    uint8_t l = (Length <= 128) ? Length : 128;
    int i;

    for (i = 0; l >= 32; i++, l = static_cast<uint8_t>(l - 32u))
        if (IPAddr.Addr[i] != addr.Addr[i])
            return false;

    if (l == 0)
        return true;

    uint32_t mask = chip::Encoding::BigEndian::HostSwap32(0xFFFFFFFF << (32 - l));
    return (IPAddr.Addr[i] & mask) == (addr.Addr[i] & mask);
}

} // namespace Inet
} // namespace chip