// Copyright (C) 2011 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. #ifndef __OPTION_INFO_H #define __OPTION_INFO_H #include #include "exceptions/exceptions.h" namespace isc { namespace badpacket { /// \brief Option Information /// /// Holds details about the options that can be specified on the command line /// that require values and which control data put in the DNS message sent to /// the remote system. /// /// Some of the fields are no applicable to all options. For example, some of /// the options correspond to fields in the flags word of the DNS message /// header, so the information includes details about the position of the fields /// and an appropriate bit mask. /// /// Note that the class does not hold values specified on the command line - it /// only holds information about the available options. class OptionInfo { public: /// \brief Array Indexes /// /// The data for the flags options are held in an array. Although declared /// as an enum, only the numeric values are used as they are the indexes /// into the array. enum Index { FLAGS_START = 0, // Start of flags field codes QR = 0, // Query/response OP = 1, // Opcode AA = 2, // Authoritative answer TC = 3, // Truncated RD = 4, // Recursion desired RA = 5, // Recursion available Z = 6, // Zero (reserved) AD = 7, // Authenticated data CD = 8, // Checking disabled RC = 9, // Response code FLAGS_END = 9, // End of flags field codes COUNT_START = 10, // Start of count fields QC = 10, // Query count AC = 11, // Answer count UC = 12, // Authority count DC = 13, // Additional count COUNT_END = 13, // End of count fields OTHER_START = 14, // Start of other fields MS = 14, // Message size OTHER_END = 14, // End of other fields SIZE = 15 // Number of index values }; /// \brief Option parameters /// /// Defines a structure that holds information associated with each of the /// flags field command options. Not all members of the structure are /// relevant to all options. struct Parameter { const char short_form; // Short form of the command switch const char* long_form; // Long form of the command switch int word; // Byte offset of word in message header uint16_t mask; // Bit mask of field in the flags word int offset; // Offset of field in flags word uint32_t defval; // Default value uint32_t minval; // Minimum valid value for this field uint32_t maxval; // Maximum valid value for this field }; /// \brief Return index for command option /// /// Given the short form of a command-line option, return the index in the /// options array corresponding to that option. /// /// \param c The character that is the short form of the command line option. /// An 'int' is used as the value passed will be the return value /// from 'getopt()' (or equivalent) which is an int. If the /// character is not found, an exception will be thrown. /// /// \return A valid index value. static int getIndex(int c); /// \brief Return long form of command switch for this field /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return The long option name (e.q. "qr" for the Query/Response field). static const char* name(int index); /// \brief Return header word offset /// /// Returns the byte offset in the DNS message header of the two-byte word /// holding the data in question. /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return The offset in the header for this datum. static int word(int index); /// \brief Return mask associated with switch field /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return The mask for this particular option in the DNS message flags /// word. The returned value is only valid for options that /// correspond to fields in the flags word. static uint16_t mask(int index); /// \brief Return offset associated with option field /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return The offset of the field corresponding to this option in the DNS /// message flags field. The returned value is only valid for /// options that correpond to fields in the flags word. static int offset(int index); /// \brief Return minimum allowed value of an option /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return Minimum allowed value for this option. static uint32_t minval(int index); /// \brief Return default value of an option /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return Default value for this option static uint32_t defval(int index); /// \brief Return maximum allowed value of an option /// /// \param index A valid index (one of the values in the 'Index' enum). /// /// \return Maximum allowed value for this option. If the option is a bit /// in the flags field of the DNS message hearder, this will be 1. static uint32_t maxval(int index); /// \brief Check Array Index /// /// Checks the passed field index and throws an exception if it does not /// correspond to one of the valid indexes in the 'Index' enum. /// /// \param index An index value. static void checkIndex(int i) { if ((i < 0) || (i >= SIZE)) { isc_throw(isc::OutOfRange, "option index must be in the range " "0 to " << SIZE); } } }; } // namespace badpacket } // namespace isc #endif // __OPTION_INFO_H