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| -rw-r--r-- | src/lib/dns/rcode.h | 338 |
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diff --git a/src/lib/dns/rcode.h b/src/lib/dns/rcode.h new file mode 100644 index 0000000..eb192cd --- /dev/null +++ b/src/lib/dns/rcode.h @@ -0,0 +1,338 @@ +/* + * Copyright (C) 2010-2015 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/. + */ + +#include <stdint.h> + +#include <ostream> + +#ifndef RCODE_H +#define RCODE_H 1 + +namespace isc { +namespace dns { + +/// \brief DNS Response Codes (RCODEs) class. +/// +/// The \c Rcode class objects represent standard Response Codes +/// (RCODEs) of the header section of DNS messages, and extended response +/// codes as defined in the EDNS specification. +/// +/// Originally RCODEs were defined as 4-bit integers (RFC1035), and then +/// extended to 12 bits as part of the %EDNS specification (RFC2671). +/// This API uses the 12-bit version of the definition from the beginning; +/// applications don't have to aware of the original definition except when +/// dealing with the wire-format representation of the %EDNS OPT RR +/// (which is rare). +/// +/// Like the \c Opcode class, Rcodes could be represented as bare integers, +/// but we define a separate class to benefit from C++ type safety. +/// +/// For convenience we also provide +/// an enum type for pre-defined RCODE values, but it is generally advisable +/// to handle RCODEs through this class. In fact, public interfaces of +/// this library uses this class to pass or return RCODEs instead of the +/// bare code values. +class Rcode { +public: + /// Constants for pre-defined RCODE values. + enum CodeValue { + NOERROR_CODE = 0, ///< 0: No error (RFC1035) + FORMERR_CODE = 1, ///< 1: Format error (RFC1035) + SERVFAIL_CODE = 2, ///< 2: Server failure (RFC1035) + NXDOMAIN_CODE = 3, ///< 3: Name Error (RFC1035) + NOTIMP_CODE = 4, ///< 4: Not Implemented (RFC1035) + REFUSED_CODE = 5, ///< 5: Refused (RFC1035) + YXDOMAIN_CODE = 6, ///< 6: Name unexpectedly exists (RFC2136) + YXRRSET_CODE = 7, ///< 7: RRset unexpectedly exists (RFC2136) + NXRRSET_CODE = 8, ///< 8: RRset should exist but not (RFC2136) + NOTAUTH_CODE = 9, ///< 9: Server isn't authoritative (RFC2136) + NOTZONE_CODE = 10, ///< 10: Name is not within the zone (RFC2136) + RESERVED11_CODE = 11, ///< 11: Reserved for future use (RFC1035) + RESERVED12_CODE = 12, ///< 12: Reserved for future use (RFC1035) + RESERVED13_CODE = 13, ///< 13: Reserved for future use (RFC1035) + RESERVED14_CODE = 14, ///< 14: Reserved for future use (RFC1035) + RESERVED15_CODE = 15, ///< 15: Reserved for future use (RFC1035) + BADVERS_CODE = 16 ///< 16: EDNS version not implemented (RFC2671) + }; + + /// \name Constructors and Destructor + /// + /// We use the default versions of destructor, copy constructor, + /// and assignment operator. + /// + /// The default constructor is hidden as a result of defining the other + /// constructors. This is intentional; we don't want to allow an + /// \c Rcode object to be constructed with an invalid state. + //@{ + /// \brief Constructor from the code value. + /// + /// Since RCODEs are 12-bit values, parameters larger than 0xfff are + /// invalid. + /// If \c code is larger than 0xfff an exception of class + /// \c isc::OutOfRange will be thrown. + /// + /// \param code The underlying 12-bit code value of the \c Rcode. + explicit Rcode(const uint16_t code); + + /// \brief Constructor from a pair of base and extended parts of code. + /// + /// This constructor takes two parameters, one for the lower 4 bits of + /// the code value, the other for the upper 8 bits, and combines them + /// to build a complete 12-bit code value. + /// + /// The first parameter, \c code, is the lower 4 bits, and therefore must + /// not exceed 15. Otherwise, an exception of class + /// \c isc::OutOfRange will be thrown. + /// + /// This version of constructor is provided specifically for constructing + /// an Rcode from a DNS header and an %EDNS OPT RR. Normal applications + /// won't have to use this constructor. + /// + /// \param code The lower 4 bits of the underlying code value. + /// \param extended_code The upper 8 bits of the underlying code value. + Rcode(const uint8_t code, const uint8_t extended_code); + //@} + + /// \brief Returns the \c Rcode code value. + /// + /// This method never throws an exception. + /// + /// \return The underlying code value corresponding to the \c Rcode. + uint16_t getCode() const { return (code_); } + + /// \brief Returns the upper 8-bit of the \c Rcode code value. + /// + /// Normal applications won't have to use this method. This is provided + /// in case the upper 8 bits are necessary for the EDNS protocol + /// processing. + /// + /// This method never throws an exception. + /// + /// \return The upper 8-bit of the underlying code value. + uint8_t getExtendedCode() const; + + /// \brief Return true iff two Rcodes are equal. + /// + /// Two Rcodes are equal iff their type codes are equal. + /// + /// This method never throws an exception. + /// + /// \param other the \c Rcode object to compare against. + /// \return true if the two Rcodes are equal; otherwise false. + bool equals(const Rcode& other) const + { return (code_ == other.code_); } + + /// \brief Same as \c equals(). + bool operator==(const Rcode& other) const { return (equals(other)); } + + /// \brief Return true iff two Rcodes are not equal. + /// + /// This method never throws an exception. + /// + /// \param other the \c Rcode object to compare against. + /// \return true if the two Rcodes are not equal; otherwise false. + bool nequals(const Rcode& other) const + { return (code_ != other.code_); } + + /// \brief Same as \c nequals(). + bool operator!=(const Rcode& other) const { return (nequals(other)); } + + /// \brief Convert the \c Rcode to a string. + /// + /// For pre-defined code values (see Rcode::CodeValue), + /// this method returns a string representation of the "mnemonic' used + /// for the enum and constant objects. For example, the string for + /// code value 0 is "NOERROR", etc. + /// For other code values it returns a string representation of the decimal + /// number of the value, e.g. "32", "100", etc. + /// + /// If resource allocation for the string fails, a corresponding standard + /// exception will be thrown. + /// + /// \return A string representation of the \c Rcode. + std::string toText() const; + + /// A constant object for the NOERROR Rcode (see \c Rcode::NOERROR_CODE). + static const Rcode& NOERROR(); + + /// A constant object for the FORMERR Rcode (see \c Rcode::FORMERR_CODE). + static const Rcode& FORMERR(); + + /// A constant object for the SERVFAIL Rcode (see \c Rcode::SERVFAIL_CODE). + static const Rcode& SERVFAIL(); + + /// A constant object for the NXDOMAIN Rcode (see \c Rcode::NXDOMAIN_CODE). + static const Rcode& NXDOMAIN(); + + /// A constant object for the NOTIMP Rcode (see \c Rcode::NOTIMP_CODE). + static const Rcode& NOTIMP(); + + /// A constant object for the REFUSED Rcode (see \c Rcode::REFUSED_CODE). + static const Rcode& REFUSED(); + + /// A constant object for the YXDOMAIN Rcode (see \c Rcode::YXDOMAIN_CODE). + static const Rcode& YXDOMAIN(); + + /// A constant object for the YXRRSET Rcode (see \c Rcode::YXRRSET_CODE). + static const Rcode& YXRRSET(); + + /// A constant object for the NXRRSET Rcode (see \c Rcode::NXRRSET_CODE). + static const Rcode& NXRRSET(); + + /// A constant object for the NOTAUTH Rcode (see \c Rcode::NOTAUTH_CODE). + static const Rcode& NOTAUTH(); + + /// A constant object for the NOTZONE Rcode (see \c Rcode::NOTZONE_CODE). + static const Rcode& NOTZONE(); + + /// A constant object for a reserved (code 11) Rcode. + /// (see \c Rcode::RESERVED11_CODE). + static const Rcode& RESERVED11(); + + /// A constant object for a reserved (code 12) Rcode. + /// (see \c Rcode::RESERVED12_CODE). + static const Rcode& RESERVED12(); + + /// A constant object for a reserved (code 13) Rcode. + /// (see \c Rcode::RESERVED13_CODE). + static const Rcode& RESERVED13(); + + /// A constant object for a reserved (code 14) Rcode. + /// (see \c Rcode::RESERVED14_CODE). + static const Rcode& RESERVED14(); + + /// A constant object for a reserved (code 15) Rcode. + /// (see \c Rcode::RESERVED15_CODE). + static const Rcode& RESERVED15(); + + /// A constant object for the BADVERS Rcode (see \c Rcode::BADVERS_CODE). + static const Rcode& BADVERS(); +private: + uint16_t code_; +}; + +inline const Rcode& +Rcode::NOERROR() { + static Rcode c(0); + return (c); +} + +inline const Rcode& +Rcode::FORMERR() { + static Rcode c(1); + return (c); +} + +inline const Rcode& +Rcode::SERVFAIL() { + static Rcode c(2); + return (c); +} + +inline const Rcode& +Rcode::NXDOMAIN() { + static Rcode c(3); + return (c); +} + +inline const Rcode& +Rcode::NOTIMP() { + static Rcode c(4); + return (c); +} + +inline const Rcode& +Rcode::REFUSED() { + static Rcode c(5); + return (c); +} + +inline const Rcode& +Rcode::YXDOMAIN() { + static Rcode c(6); + return (c); +} + +inline const Rcode& +Rcode::YXRRSET() { + static Rcode c(7); + return (c); +} + +inline const Rcode& +Rcode::NXRRSET() { + static Rcode c(8); + return (c); +} + +inline const Rcode& +Rcode::NOTAUTH() { + static Rcode c(9); + return (c); +} + +inline const Rcode& +Rcode::NOTZONE() { + static Rcode c(10); + return (c); +} + +inline const Rcode& +Rcode::RESERVED11() { + static Rcode c(11); + return (c); +} + +inline const Rcode& +Rcode::RESERVED12() { + static Rcode c(12); + return (c); +} + +inline const Rcode& +Rcode::RESERVED13() { + static Rcode c(13); + return (c); +} + +inline const Rcode& +Rcode::RESERVED14() { + static Rcode c(14); + return (c); +} + +inline const Rcode& +Rcode::RESERVED15() { + static Rcode c(15); + return (c); +} + +inline const Rcode& +Rcode::BADVERS() { + static Rcode c(16); + return (c); +} + +/// \brief Insert the \c Rcode as a string into stream. +/// +/// This method convert \c rcode into a string and inserts it into the +/// output stream \c os. +/// +/// \param os A \c std::ostream object on which the insertion operation is +/// performed. +/// \param rcode A reference to an \c Rcode object output by the operation. +/// \return A reference to the same \c std::ostream object referenced by +/// parameter \c os after the insertion operation. +std::ostream& operator<<(std::ostream& os, const Rcode& rcode); +} +} +#endif // RCODE_H + +// Local Variables: +// mode: c++ +// End: |