option_int.h

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// Copyright (C) 2012-2022 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef OPTION_INT_H
#define OPTION_INT_H

#include <dhcp/libdhcp++.h>
#include <dhcp/option.h>
#include <dhcp/option_data_types.h>
#include <dhcp/option_space.h>
#include <util/io_utilities.h>

#include <stdint.h>
#include <sstream>

namespace isc {
namespace dhcp {

template<typename T>
class OptionInt;

typedef OptionInt<uint8_t> OptionUint8;
typedef boost::shared_ptr<OptionUint8> OptionUint8Ptr;
typedef OptionInt<uint16_t> OptionUint16;
typedef boost::shared_ptr<OptionUint16> OptionUint16Ptr;
typedef OptionInt<uint32_t> OptionUint32;
typedef boost::shared_ptr<OptionUint32> OptionUint32Ptr;

template<typename T>
class OptionInt: public Option {
private:

    typedef boost::shared_ptr<OptionInt<T> > OptionIntTypePtr;

public:
    OptionInt(Option::Universe u, uint16_t type, T value)
        : Option(u, type), value_(value) {
        if (!OptionDataTypeTraits<T>::integer_type) {
            isc_throw(dhcp::InvalidDataType, "non-integer type");
        }
        setEncapsulatedSpace(u == Option::V4 ? DHCP4_OPTION_SPACE : DHCP6_OPTION_SPACE);
    }

    OptionInt(Option::Universe u, uint16_t type, OptionBufferConstIter begin,
               OptionBufferConstIter end)
        : Option(u, type) {
        if (!OptionDataTypeTraits<T>::integer_type) {
            isc_throw(dhcp::InvalidDataType, "non-integer type");
        }
        setEncapsulatedSpace(u == Option::V4 ? DHCP4_OPTION_SPACE : DHCP6_OPTION_SPACE);
        unpack(begin, end);
    }

    virtual OptionPtr clone() const {
        return (cloneInternal<OptionInt<T> >());
    }

    virtual void pack(isc::util::OutputBuffer& buf, bool check = true) const {
        // Pack option header.
        packHeader(buf, check);
        // Depending on the data type length we use different utility functions
        // writeUint16 or writeUint32 which write the data in the network byte
        // order to the provided buffer. The same functions can be safely used
        // for either unsigned or signed integers so there is not need to create
        // special cases for intX_t types.
        switch (OptionDataTypeTraits<T>::len) {
        case 1:
            buf.writeUint8(value_);
            break;
        case 2:
            buf.writeUint16(value_);
            break;
        case 4:
            buf.writeUint32(value_);
            break;
        default:
            isc_throw(dhcp::InvalidDataType, "non-integer type");
        }
        packOptions(buf, check);
    }

    virtual void unpack(OptionBufferConstIter begin, OptionBufferConstIter end) {
        if (distance(begin, end) < sizeof(T)) {
            isc_throw(OutOfRange, "OptionInt " << getType() << " truncated");
        }
        // @todo consider what to do if buffer is longer than data type.

        // Depending on the data type length we use different utility functions
        // readUint16 or readUint32 which read the data laid in the network byte
        // order from the provided buffer. The same functions can be safely used
        // for either unsigned or signed integers so there is not need to create
        // special cases for intX_t types.
        int data_size_len = OptionDataTypeTraits<T>::len;
        switch (data_size_len) {
        case 1:
            value_ = *begin;
            break;
        case 2:
            value_ = isc::util::readUint16(&(*begin),
                                           std::distance(begin, end));
            break;
        case 4:
            value_ = isc::util::readUint32(&(*begin),
                                           std::distance(begin, end));
            break;
        default:
            isc_throw(dhcp::InvalidDataType, "non-integer type");
        }
        // Use local variable to set a new value for this iterator.
        // When using OptionDataTypeTraits<T>::len directly some versions
        // of clang complain about unresolved reference to
        // OptionDataTypeTraits structure during linking.
        begin += data_size_len;
        unpackOptions(OptionBuffer(begin, end));
    }

    void setValue(T value) { value_ = value; }

    T getValue() const { return value_; }

    virtual uint16_t len() const {
        // Calculate the length of the header.
        uint16_t length = (getUniverse() == Option::V4) ? OPTION4_HDR_LEN : OPTION6_HDR_LEN;
        // The data length is equal to size of T.
        length += sizeof(T);;
        // length of all suboptions
        for (OptionCollection::const_iterator it = options_.begin();
             it != options_.end();
             ++it) {
            length += (*it).second->len();
        }
        return (length);
    }

    virtual std::string toText(int indent = 0) const {
        std::stringstream output;
        output << headerToText(indent) << ": ";

        // For 1 byte long data types we need to cast to the integer
        // because they are usually implemented as "char" types, in
        // which case the character rather than number would be printed.
        if (OptionDataTypeTraits<T>::len == 1) {
            output << static_cast<int>(getValue());
        } else {
            output << getValue();
        }

        // Append data type name.
        output << " ("
               << OptionDataTypeUtil::getDataTypeName(OptionDataTypeTraits<T>::type)
               << ")";

        // Append suboptions.
        output << suboptionsToText(indent + 2);

        return (output.str());
    }

private:

    T value_;  
};

} // isc::dhcp namespace
} // isc namespace

#endif // OPTION_INT_H