trust-dns 0.11.0

TRust-DNS is a safe and secure DNS library. This is the Client library with DNSec support. DNSSec with NSEC validation for negative records, is complete. The client supports dynamic DNS with SIG0 authenticated requests, implementing easy to use high level funtions. TRust-DNS is based on the Tokio and Futures libraries, which means it should be easily integrated into other software that also use those libraries.
Documentation
/*
 * Copyright (C) 2015 Benjamin Fry <benjaminfry@me.com>
 *
 * 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.
 */

//! record data enum variants

use std::net::{Ipv4Addr, Ipv6Addr};
#[cfg(test)]
use std::convert::From;
use std::cmp::Ordering;

use error::*;
use serialize::binary::*;
use serialize::txt::*;
use super::domain::Name;
use super::record_type::RecordType;
use super::rdata;
use super::rdata::{DNSKEY, DS, KEY, MX, NSEC, NSEC3, NSEC3PARAM, NULL, OPT, SIG, SOA, SRV, TXT};

/// Record data enum variants
///
/// [RFC 1035](https://tools.ietf.org/html/rfc1035), DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION, November 1987
///
/// ```text
/// 3.3. Standard RRs
///
/// The following RR definitions are expected to occur, at least
/// potentially, in all classes.  In particular, NS, SOA, CNAME, and PTR
/// will be used in all classes, and have the same format in all classes.
/// Because their RDATA format is known, all domain names in the RDATA
/// section of these RRs may be compressed.
///
/// <domain-name> is a domain name represented as a series of labels, and
/// terminated by a label with zero length.  <character-string> is a single
/// length octet followed by that number of characters.  <character-string>
/// is treated as binary information, and can be up to 256 characters in
/// length (including the length octet).
/// ```
#[derive(Debug, PartialEq, Clone, Eq)]
pub enum RData {
    /// ```text
    /// -- RFC 1035 -- Domain Implementation and Specification    November 1987
    ///
    /// 3.4. Internet specific RRs
    ///
    /// 3.4.1. A RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    ADDRESS                    |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// ADDRESS         A 32 bit Internet address.
    ///
    /// Hosts that have multiple Internet addresses will have multiple A
    /// records.
    ///
    /// A records cause no additional section processing.  The RDATA section of
    /// an A line in a master file is an Internet address expressed as four
    /// decimal numbers separated by dots without any imbedded spaces (e.g.,
    /// "10.2.0.52" or "192.0.5.6").
    /// ```
    A(Ipv4Addr),

    /// ```text
    /// -- RFC 1886 -- IPv6 DNS Extensions              December 1995
    ///
    /// 2.2 AAAA data format
    ///
    ///    A 128 bit IPv6 address is encoded in the data portion of an AAAA
    ///    resource record in network byte order (high-order byte first).
    /// ```
    AAAA(Ipv6Addr),

    /// ```text
    ///   3.3. Standard RRs
    ///
    /// The following RR definitions are expected to occur, at least
    /// potentially, in all classes.  In particular, NS, SOA, CNAME, and PTR
    /// will be used in all classes, and have the same format in all classes.
    /// Because their RDATA format is known, all domain names in the RDATA
    /// section of these RRs may be compressed.
    ///
    /// <domain-name> is a domain name represented as a series of labels, and
    /// terminated by a label with zero length.  <character-string> is a single
    /// length octet followed by that number of characters.  <character-string>
    /// is treated as binary information, and can be up to 256 characters in
    /// length (including the length octet).
    ///
    /// 3.3.1. CNAME RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                     CNAME                     /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// CNAME           A <domain-name> which specifies the canonical or primary
    ///                 name for the owner.  The owner name is an alias.
    ///
    /// CNAME RRs cause no additional section processing, but name servers may
    /// choose to restart the query at the canonical name in certain cases.  See
    /// the description of name server logic in [RFC-1034] for details.
    /// ```
    CNAME(Name),

    /// ```text
    /// RFC 4034                DNSSEC Resource Records               March 2005
    ///
    /// 2.1.  DNSKEY RDATA Wire Format
    ///
    ///    The RDATA for a DNSKEY RR consists of a 2 octet Flags Field, a 1
    ///    octet Protocol Field, a 1 octet Algorithm Field, and the Public Key
    ///    Field.
    ///
    ///                         1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |              Flags            |    Protocol   |   Algorithm   |
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    /                                                               /
    ///    /                            Public Key                         /
    ///    /                                                               /
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///
    /// 2.1.1.  The Flags Field
    ///
    ///    Bit 7 of the Flags field is the Zone Key flag.  If bit 7 has value 1,
    ///    then the DNSKEY record holds a DNS zone key, and the DNSKEY RR's
    ///    owner name MUST be the name of a zone.  If bit 7 has value 0, then
    ///    the DNSKEY record holds some other type of DNS public key and MUST
    ///    NOT be used to verify RRSIGs that cover RRsets.
    ///
    ///    Bit 15 of the Flags field is the Secure Entry Point flag, described
    ///    in [RFC3757].  If bit 15 has value 1, then the DNSKEY record holds a
    ///    key intended for use as a secure entry point.  This flag is only
    ///    intended to be a hint to zone signing or debugging software as to the
    ///    intended use of this DNSKEY record; validators MUST NOT alter their
    ///    behavior during the signature validation process in any way based on
    ///    the setting of this bit.  This also means that a DNSKEY RR with the
    ///    SEP bit set would also need the Zone Key flag set in order to be able
    ///    to generate signatures legally.  A DNSKEY RR with the SEP set and the
    ///    Zone Key flag not set MUST NOT be used to verify RRSIGs that cover
    ///    RRsets.
    ///
    ///    Bits 0-6 and 8-14 are reserved: these bits MUST have value 0 upon
    ///    creation of the DNSKEY RR and MUST be ignored upon receipt.
    ///
    /// RFC 5011                  Trust Anchor Update             September 2007
    ///
    /// 7.  IANA Considerations
    ///
    ///   The IANA has assigned a bit in the DNSKEY flags field (see Section 7
    ///   of [RFC4034]) for the REVOKE bit (8).
    /// ```
    DNSKEY(DNSKEY),

    /// ```text
    /// 5.1.  DS RDATA Wire Format
    ///
    /// The RDATA for a DS RR consists of a 2 octet Key Tag field, a 1 octet
    ///           Algorithm field, a 1 octet Digest Type field, and a Digest field.
    ///
    ///                          1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///     |           Key Tag             |  Algorithm    |  Digest Type  |
    ///     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///     /                                                               /
    ///     /                            Digest                             /
    ///     /                                                               /
    ///     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///
    /// 5.1.1.  The Key Tag Field
    ///
    ///    The Key Tag field lists the key tag of the DNSKEY RR referred to by
    ///    the DS record, in network byte order.
    ///
    ///    The Key Tag used by the DS RR is identical to the Key Tag used by
    ///    RRSIG RRs.  Appendix B describes how to compute a Key Tag.
    ///
    /// 5.1.2.  The Algorithm Field
    ///
    ///    The Algorithm field lists the algorithm number of the DNSKEY RR
    ///    referred to by the DS record.
    ///
    ///    The algorithm number used by the DS RR is identical to the algorithm
    ///    number used by RRSIG and DNSKEY RRs.  Appendix A.1 lists the
    ///    algorithm number types.
    ///
    /// 5.1.3.  The Digest Type Field
    ///
    ///    The DS RR refers to a DNSKEY RR by including a digest of that DNSKEY
    ///    RR.  The Digest Type field identifies the algorithm used to construct
    ///    the digest.  Appendix A.2 lists the possible digest algorithm types.
    ///
    /// 5.1.4.  The Digest Field
    ///
    ///    The DS record refers to a DNSKEY RR by including a digest of that
    ///    DNSKEY RR.
    ///
    ///    The digest is calculated by concatenating the canonical form of the
    ///    fully qualified owner name of the DNSKEY RR with the DNSKEY RDATA,
    ///    and then applying the digest algorithm.
    ///
    ///      digest = digest_algorithm( DNSKEY owner name | DNSKEY RDATA);
    ///
    ///       "|" denotes concatenation
    ///
    ///      DNSKEY RDATA = Flags | Protocol | Algorithm | Public Key.
    ///
    ///    The size of the digest may vary depending on the digest algorithm and
    ///    DNSKEY RR size.  As of the time of this writing, the only defined
    ///    digest algorithm is SHA-1, which produces a 20 octet digest.
    /// ```
    DS(DS),

    /// ```text
    /// RFC 2535                DNS Security Extensions               March 1999
    ///
    /// 3.1 KEY RDATA format
    ///
    ///  The RDATA for a KEY RR consists of flags, a protocol octet, the
    ///  algorithm number octet, and the public key itself.  The format is as
    ///  follows:
    ///
    ///                       1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |             flags             |    protocol   |   algorithm   |
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |                                                               /
    ///  /                          public key                           /
    ///  /                                                               /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
    ///
    ///  The KEY RR is not intended for storage of certificates and a separate
    ///  certificate RR has been developed for that purpose, defined in [RFC
    ///  2538].
    ///
    ///  The meaning of the KEY RR owner name, flags, and protocol octet are
    ///  described in Sections 3.1.1 through 3.1.5 below.  The flags and
    ///  algorithm must be examined before any data following the algorithm
    ///  octet as they control the existence and format of any following data.
    ///  The algorithm and public key fields are described in Section 3.2.
    ///  The format of the public key is algorithm dependent.
    ///
    ///  KEY RRs do not specify their validity period but their authenticating
    ///  SIG RR(s) do as described in Section 4 below.
    /// ```
    KEY(KEY),

    /// ```text
    /// 3.3.9. MX RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                  PREFERENCE                   |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   EXCHANGE                    /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ////
    /// where:
    ///
    /// PREFERENCE      A 16 bit integer which specifies the preference given to
    ///                 this RR among others at the same owner.  Lower values
    ///                 are preferred.
    ///
    /// EXCHANGE        A <domain-name> which specifies a host willing to act as
    ///                 a mail exchange for the owner name.
    ///
    /// MX records cause type A additional section processing for the host
    /// specified by EXCHANGE.  The use of MX RRs is explained in detail in
    /// [RFC-974].
    /// ```
    MX(MX),

    /// ```text
    /// 3.3.10. NULL RDATA format (EXPERIMENTAL)
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                  <anything>                   /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// Anything at all may be in the RDATA field so long as it is 65535 octets
    /// or less.
    ///
    /// NULL records cause no additional section processing.  NULL RRs are not
    /// allowed in master files.  NULLs are used as placeholders in some
    /// experimental extensions of the DNS.
    /// ```
    NULL(NULL),

    /// ```text
    /// 3.3.11. NS RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   NSDNAME                     /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// NSDNAME         A <domain-name> which specifies a host which should be
    ///                 authoritative for the specified class and domain.
    ///
    /// NS records cause both the usual additional section processing to locate
    /// a type A record, and, when used in a referral, a special search of the
    /// zone in which they reside for glue information.
    ///
    /// The NS RR states that the named host should be expected to have a zone
    /// starting at owner name of the specified class.  Note that the class may
    /// not indicate the protocol family which should be used to communicate
    /// with the host, although it is typically a strong hint.  For example,
    /// hosts which are name servers for either Internet (IN) or Hesiod (HS)
    /// class information are normally queried using IN class protocols.
    /// ```
    NS(Name),

    /// ```text
    /// RFC 4034                DNSSEC Resource Records               March 2005
    ///
    /// 4.1.  NSEC RDATA Wire Format
    ///
    ///  The RDATA of the NSEC RR is as shown below:
    ///
    ///                       1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  /                      Next Domain Name                         /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  /                       Type Bit Maps                           /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    /// ```
    NSEC(NSEC),

    /// ```text
    /// RFC 5155                         NSEC3                        March 2008
    ///
    /// 3.2.  NSEC3 RDATA Wire Format
    ///
    ///  The RDATA of the NSEC3 RR is as shown below:
    ///
    ///                       1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |   Hash Alg.   |     Flags     |          Iterations           |
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |  Salt Length  |                     Salt                      /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |  Hash Length  |             Next Hashed Owner Name            /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  /                         Type Bit Maps                         /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///
    ///  Hash Algorithm is a single octet.
    ///
    ///  Flags field is a single octet, the Opt-Out flag is the least
    ///  significant bit, as shown below:
    ///
    ///   0 1 2 3 4 5 6 7
    ///  +-+-+-+-+-+-+-+-+
    ///  |             |O|
    ///  +-+-+-+-+-+-+-+-+
    ///
    ///  Iterations is represented as a 16-bit unsigned integer, with the most
    ///  significant bit first.
    ///
    ///  Salt Length is represented as an unsigned octet.  Salt Length
    ///  represents the length of the Salt field in octets.  If the value is
    ///  zero, the following Salt field is omitted.
    ///
    ///  Salt, if present, is encoded as a sequence of binary octets.  The
    ///  length of this field is determined by the preceding Salt Length
    ///  field.
    ///
    ///  Hash Length is represented as an unsigned octet.  Hash Length
    ///  represents the length of the Next Hashed Owner Name field in octets.
    ///
    ///  The next hashed owner name is not base32 encoded, unlike the owner
    ///  name of the NSEC3 RR.  It is the unmodified binary hash value.  It
    ///  does not include the name of the containing zone.  The length of this
    ///  field is determined by the preceding Hash Length field.
    ///
    /// 3.2.1.  Type Bit Maps Encoding
    ///
    ///  The encoding of the Type Bit Maps field is the same as that used by
    ///  the NSEC RR, described in [RFC4034].  It is explained and clarified
    ///  here for clarity.
    ///
    ///  The RR type space is split into 256 window blocks, each representing
    ///  the low-order 8 bits of the 16-bit RR type space.  Each block that
    ///  has at least one active RR type is encoded using a single octet
    ///  window number (from 0 to 255), a single octet bitmap length (from 1
    ///  to 32) indicating the number of octets used for the bitmap of the
    ///  window block, and up to 32 octets (256 bits) of bitmap.
    ///
    ///  Blocks are present in the NSEC3 RR RDATA in increasing numerical
    ///  order.
    ///
    ///     Type Bit Maps Field = ( Window Block # | Bitmap Length | Bitmap )+
    ///
    ///     where "|" denotes concatenation.
    ///
    ///  Each bitmap encodes the low-order 8 bits of RR types within the
    ///  window block, in network bit order.  The first bit is bit 0.  For
    ///  window block 0, bit 1 corresponds to RR type 1 (A), bit 2 corresponds
    ///  to RR type 2 (NS), and so forth.  For window block 1, bit 1
    ///  corresponds to RR type 257, bit 2 to RR type 258.  If a bit is set to
    ///  1, it indicates that an RRSet of that type is present for the
    ///  original owner name of the NSEC3 RR.  If a bit is set to 0, it
    ///  indicates that no RRSet of that type is present for the original
    ///  owner name of the NSEC3 RR.
    ///
    ///  Since bit 0 in window block 0 refers to the non-existing RR type 0,
    ///  it MUST be set to 0.  After verification, the validator MUST ignore
    ///  the value of bit 0 in window block 0.
    ///
    ///  Bits representing Meta-TYPEs or QTYPEs as specified in Section 3.1 of
    ///  [RFC2929] or within the range reserved for assignment only to QTYPEs
    ///  and Meta-TYPEs MUST be set to 0, since they do not appear in zone
    ///  data.  If encountered, they must be ignored upon reading.
    ///
    ///  Blocks with no types present MUST NOT be included.  Trailing zero
    ///  octets in the bitmap MUST be omitted.  The length of the bitmap of
    ///  each block is determined by the type code with the largest numerical
    ///  value, within that block, among the set of RR types present at the
    ///  original owner name of the NSEC3 RR.  Trailing octets not specified
    ///  MUST be interpreted as zero octets.
    /// ```
    NSEC3(NSEC3),

    /// ```text
    /// RFC 5155                         NSEC3                        March 2008
    ///
    /// 4.2.  NSEC3PARAM RDATA Wire Format
    ///
    ///  The RDATA of the NSEC3PARAM RR is as shown below:
    ///
    ///                       1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |   Hash Alg.   |     Flags     |          Iterations           |
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///  |  Salt Length  |                     Salt                      /
    ///  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///
    ///  Hash Algorithm is a single octet.
    ///
    ///  Flags field is a single octet.
    ///
    ///  Iterations is represented as a 16-bit unsigned integer, with the most
    ///  significant bit first.
    ///
    ///  Salt Length is represented as an unsigned octet.  Salt Length
    ///  represents the length of the following Salt field in octets.  If the
    ///  value is zero, the Salt field is omitted.
    ///
    ///  Salt, if present, is encoded as a sequence of binary octets.  The
    ///  length of this field is determined by the preceding Salt Length
    ///  field.
    /// ```
    NSEC3PARAM(NSEC3PARAM),

    /// ```text
    /// RFC 6891                   EDNS(0) Extensions                 April 2013
    /// 6.1.2.  Wire Format
    ///
    ///        +------------+--------------+------------------------------+
    ///        | Field Name | Field Type   | Description                  |
    ///        +------------+--------------+------------------------------+
    ///        | NAME       | domain name  | MUST be 0 (root domain)      |
    ///        | TYPE       | u_int16_t    | OPT (41)                     |
    ///        | CLASS      | u_int16_t    | requestor's UDP payload size |
    ///        | TTL        | u_int32_t    | extended RCODE and flags     |
    ///        | RDLEN      | u_int16_t    | length of all RDATA          |
    ///        | RDATA      | octet stream | {attribute,value} pairs      |
    ///        +------------+--------------+------------------------------+
    ///
    /// The variable part of an OPT RR may contain zero or more options in
    ///    the RDATA.  Each option MUST be treated as a bit field.  Each option
    ///    is encoded as:
    ///
    ///                   +0 (MSB)                            +1 (LSB)
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    ///     0: |                          OPTION-CODE                          |
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    ///     2: |                         OPTION-LENGTH                         |
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    ///     4: |                                                               |
    ///        /                          OPTION-DATA                          /
    ///        /                                                               /
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    /// ```
    OPT(OPT),

    /// ```text
    /// 3.3.12. PTR RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   PTRDNAME                    /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// PTRDNAME        A <domain-name> which points to some location in the
    ///                 domain name space.
    ///
    /// PTR records cause no additional section processing.  These RRs are used
    /// in special domains to point to some other location in the domain space.
    /// These records are simple data, and don't imply any special processing
    /// similar to that performed by CNAME, which identifies aliases.  See the
    /// description of the IN-ADDR.ARPA domain for an example.
    /// ```
    PTR(Name),

    /// ```text
    /// RFC 2535 & 2931   DNS Security Extensions               March 1999
    /// RFC 4034          DNSSEC Resource Records               March 2005
    ///
    /// 3.1.  RRSIG RDATA Wire Format
    ///
    ///    The RDATA for an RRSIG RR consists of a 2 octet Type Covered field, a
    ///    1 octet Algorithm field, a 1 octet Labels field, a 4 octet Original
    ///    TTL field, a 4 octet Signature Expiration field, a 4 octet Signature
    ///    Inception field, a 2 octet Key tag, the Signer's Name field, and the
    ///    Signature field.
    ///
    ///                         1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |        Type Covered           |  Algorithm    |     Labels    |
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |                         Original TTL                          |
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |                      Signature Expiration                     |
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |                      Signature Inception                      |
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |            Key Tag            |                               /
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+         Signer's Name         /
    ///    /                                                               /
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    /                                                               /
    ///    /                            Signature                          /
    ///    /                                                               /
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    /// ```
    SIG(SIG),

    /// ```text
    /// 3.3.13. SOA RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                     MNAME                     /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                     RNAME                     /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    SERIAL                     |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    REFRESH                    |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                     RETRY                     |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    EXPIRE                     |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    MINIMUM                    |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// MNAME           The <domain-name> of the name server that was the
    ///                 original or primary source of data for this zone.
    ///
    /// RNAME           A <domain-name> which specifies the mailbox of the
    ///                 person responsible for this zone.
    ///
    //// SERIAL          The unsigned 32 bit version number of the original copy
    ///                 of the zone.  Zone transfers preserve this value.  This
    ///                 value wraps and should be compared using sequence space
    ///                 arithmetic.
    ///
    /// REFRESH         A 32 bit time interval before the zone should be
    ///                 refreshed.
    ///
    /// RETRY           A 32 bit time interval that should elapse before a
    ///                 failed refresh should be retried.
    ///
    /// EXPIRE          A 32 bit time value that specifies the upper limit on
    ///                 the time interval that can elapse before the zone is no
    ///                 longer authoritative.
    ///
    /// MINIMUM         The unsigned 32 bit minimum TTL field that should be
    ///                 exported with any RR from this zone.
    ///
    /// SOA records cause no additional section processing.
    ///
    /// All times are in units of seconds.
    ///
    /// Most of these fields are pertinent only for name server maintenance
    /// operations.  However, MINIMUM is used in all query operations that
    /// retrieve RRs from a zone.  Whenever a RR is sent in a response to a
    /// query, the TTL field is set to the maximum of the TTL field from the RR
    /// and the MINIMUM field in the appropriate SOA.  Thus MINIMUM is a lower
    /// bound on the TTL field for all RRs in a zone.  Note that this use of
    /// MINIMUM should occur when the RRs are copied into the response and not
    /// when the zone is loaded from a master file or via a zone transfer.  The
    /// reason for this provison is to allow future dynamic update facilities to
    /// change the SOA RR with known semantics.
    /// ```
    SOA(SOA),

    /// ```text
    /// RFC 2782                       DNS SRV RR                  February 2000
    ///
    /// The format of the SRV RR
    ///
    ///  _Service._Proto.Name TTL Class SRV Priority Weight Port Target
    /// ```
    SRV(SRV),

    /// ```text
    /// 3.3.14. TXT RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   TXT-DATA                    /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// TXT-DATA        One or more <character-string>s.
    ///
    /// TXT RRs are used to hold descriptive text.  The semantics of the text
    /// depends on the domain where it is found.
    /// ```
    TXT(TXT),
}

impl RData {
    /// Parse the RData from a set of Tokens
    pub fn parse(
        record_type: RecordType,
        tokens: &Vec<Token>,
        origin: Option<&Name>,
    ) -> ParseResult<Self> {
        let rdata = match record_type {
            RecordType::A => RData::A(try!(rdata::a::parse(tokens))),
            RecordType::AAAA => RData::AAAA(try!(rdata::aaaa::parse(tokens))),
            RecordType::ANY => panic!("parsing ANY doesn't make sense"), // valid panic, never should happen
            RecordType::AXFR => panic!("parsing AXFR doesn't make sense"), // valid panic, never should happen
            RecordType::CNAME => RData::CNAME(try!(rdata::name::parse(tokens, origin))),
            RecordType::KEY => panic!("KEY should be dynamically generated"), // valid panic, never should happen
            RecordType::DNSKEY => panic!("DNSKEY should be dynamically generated"), // valid panic, never should happen
            RecordType::DS => panic!("DS should be dynamically generated"), // valid panic, never should happen
            RecordType::IXFR => panic!("parsing IXFR doesn't make sense"), // valid panic, never should happen
            RecordType::MX => RData::MX(try!(rdata::mx::parse(tokens, origin))),
            RecordType::NULL => RData::NULL(try!(rdata::null::parse(tokens))),
            RecordType::NS => RData::NS(try!(rdata::name::parse(tokens, origin))),
            RecordType::NSEC => panic!("NSEC should be dynamically generated"), // valid panic, never should happen
            RecordType::NSEC3 => panic!("NSEC3 should be dynamically generated"), // valid panic, never should happen
            RecordType::NSEC3PARAM => panic!("NSEC3PARAM should be dynamically generated"), // valid panic, never should happen
            RecordType::OPT => panic!("parsing OPT doesn't make sense"), // valid panic, never should happen
            RecordType::PTR => RData::PTR(try!(rdata::name::parse(tokens, origin))),
            RecordType::RRSIG => panic!("RRSIG should be dynamically generated"), // valid panic, never should happen
            RecordType::SIG => panic!("parsing SIG doesn't make sense"), // valid panic, never should happen
            RecordType::SOA => RData::SOA(try!(rdata::soa::parse(tokens, origin))),
            RecordType::SRV => RData::SRV(try!(rdata::srv::parse(tokens, origin))),
            RecordType::TXT => RData::TXT(try!(rdata::txt::parse(tokens))),
        };

        Ok(rdata)
    }

    fn to_bytes(&self) -> Vec<u8> {
        let mut buf: Vec<u8> = Vec::new();
        {
            let mut encoder: BinEncoder = BinEncoder::new(&mut buf);
            self.emit(&mut encoder).unwrap_or_else(|_| {
                warn!("could not encode RDATA: {:?}", self);
                ()
            });
        }
        buf
    }

    /// Read the RData from the given Decoder
    pub fn read(
        decoder: &mut BinDecoder,
        record_type: RecordType,
        rdata_length: u16,
    ) -> DecodeResult<Self> {
        let start_idx = decoder.index();

        let result = match record_type {
            RecordType::A => {
                debug!("reading A");
                RData::A(try!(rdata::a::read(decoder)))
            }
            RecordType::AAAA => {
                debug!("reading AAAA");
                RData::AAAA(try!(rdata::aaaa::read(decoder)))
            }
            rt @ RecordType::ANY => {
                return Err(DecodeErrorKind::UnknownRecordTypeValue(rt.into()).into())
            }
            rt @ RecordType::AXFR => {
                return Err(DecodeErrorKind::UnknownRecordTypeValue(rt.into()).into())
            }
            RecordType::CNAME => {
                debug!("reading CNAME");
                RData::CNAME(try!(rdata::name::read(decoder)))
            }
            RecordType::DNSKEY => {
                debug!("reading DNSKEY");
                RData::DNSKEY(try!(rdata::dnskey::read(decoder, rdata_length)))
            }
            RecordType::DS => {
                debug!("reading DS");
                RData::DS(try!(rdata::ds::read(decoder, rdata_length)))
            }
            rt @ RecordType::IXFR => {
                return Err(DecodeErrorKind::UnknownRecordTypeValue(rt.into()).into())
            }
            RecordType::KEY => {
                debug!("reading KEY");
                RData::KEY(try!(rdata::key::read(decoder, rdata_length)))
            }
            RecordType::MX => {
                debug!("reading MX");
                RData::MX(try!(rdata::mx::read(decoder)))
            }
            RecordType::NULL => {
                debug!("reading NULL");
                RData::NULL(try!(rdata::null::read(decoder, rdata_length)))
            }
            RecordType::NS => {
                debug!("reading NS");
                RData::NS(try!(rdata::name::read(decoder)))
            }
            RecordType::NSEC => {
                debug!("reading NSEC");
                RData::NSEC(try!(rdata::nsec::read(decoder, rdata_length)))
            }
            RecordType::NSEC3 => {
                debug!("reading NSEC3");
                RData::NSEC3(try!(rdata::nsec3::read(decoder, rdata_length)))
            }
            RecordType::NSEC3PARAM => {
                debug!("reading NSEC3PARAM");
                RData::NSEC3PARAM(try!(rdata::nsec3param::read(decoder)))
            }
            RecordType::OPT => {
                debug!("reading OPT");
                RData::OPT(try!(rdata::opt::read(decoder, rdata_length)))
            }
            RecordType::PTR => {
                debug!("reading PTR");
                RData::PTR(try!(rdata::name::read(decoder)))
            }
            RecordType::RRSIG => {
                debug!("reading RRSIG");
                RData::SIG(try!(rdata::sig::read(decoder, rdata_length)))
            }
            RecordType::SIG => {
                debug!("reading SIG");
                RData::SIG(try!(rdata::sig::read(decoder, rdata_length)))
            }
            RecordType::SOA => {
                debug!("reading SOA");
                RData::SOA(try!(rdata::soa::read(decoder)))
            }
            RecordType::SRV => {
                debug!("reading SRV");
                RData::SRV(try!(rdata::srv::read(decoder)))
            }
            RecordType::TXT => {
                debug!("reading TXT");
                RData::TXT(try!(rdata::txt::read(decoder, rdata_length)))
            }
        };

        // we should have read rdata_length, but we did not
        let read = decoder.index() - start_idx;
        if read != rdata_length as usize {
            return Err(
                DecodeErrorKind::IncorrectRDataLengthRead(read, rdata_length as usize).into(),
            );
        }
        Ok(result)
    }

    /// [RFC 4034](https://tools.ietf.org/html/rfc4034#section-6), DNSSEC Resource Records, March 2005
    ///
    /// ```text
    /// 6.2.  Canonical RR Form
    ///
    ///    For the purposes of DNS security, the canonical form of an RR is the
    ///    wire format of the RR where:
    ///
    ///    ...
    ///
    ///    3.  if the type of the RR is NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
    ///        HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX,
    ///        SRV, DNAME, A6, RRSIG, or (rfc6840 removes NSEC), all uppercase
    ///        US-ASCII letters in the DNS names contained within the RDATA are replaced
    ///        by the corresponding lowercase US-ASCII letters;
    /// ```
    pub fn emit(&self, encoder: &mut BinEncoder) -> EncodeResult {
        match *self {
            RData::A(ref address) => rdata::a::emit(encoder, address),
            RData::AAAA(ref address) => rdata::aaaa::emit(encoder, address),
            // to_lowercase for rfc4034 and rfc6840
            RData::CNAME(ref name) => rdata::name::emit(encoder, name),
            RData::DS(ref ds) => rdata::ds::emit(encoder, ds),
            RData::KEY(ref key) => rdata::key::emit(encoder, key),
            RData::DNSKEY(ref dnskey) => rdata::dnskey::emit(encoder, dnskey),
            // to_lowercase for rfc4034 and rfc6840
            RData::MX(ref mx) => rdata::mx::emit(encoder, mx),
            RData::NULL(ref null) => rdata::null::emit(encoder, null),
            // to_lowercase for rfc4034 and rfc6840
            RData::NS(ref name) => rdata::name::emit(encoder, name),
            RData::NSEC(ref nsec) => rdata::nsec::emit(encoder, nsec),
            RData::NSEC3(ref nsec3) => rdata::nsec3::emit(encoder, nsec3),
            RData::NSEC3PARAM(ref nsec3param) => rdata::nsec3param::emit(encoder, nsec3param),
            RData::OPT(ref opt) => rdata::opt::emit(encoder, opt),
            // to_lowercase for rfc4034 and rfc6840
            RData::PTR(ref name) => rdata::name::emit(encoder, name),
            // to_lowercase for rfc4034 and rfc6840
            RData::SIG(ref sig) => rdata::sig::emit(encoder, sig),
            // to_lowercase for rfc4034 and rfc6840
            RData::SOA(ref soa) => rdata::soa::emit(encoder, soa),
            // to_lowercase for rfc4034 and rfc6840
            RData::SRV(ref srv) => rdata::srv::emit(encoder, srv),
            RData::TXT(ref txt) => rdata::txt::emit(encoder, txt),
        }
    }

    /// Converts this to a Recordtyp
    pub fn to_record_type(&self) -> RecordType {
        match *self {
            RData::A(..) => RecordType::A,
            RData::AAAA(..) => RecordType::AAAA,
            RData::CNAME(..) => RecordType::CNAME,
            RData::DS(..) => RecordType::DS,
            RData::KEY(..) => RecordType::KEY,
            RData::DNSKEY(..) => RecordType::DNSKEY,
            RData::MX(..) => RecordType::MX,
            RData::NS(..) => RecordType::NS,
            RData::NSEC(..) => RecordType::NSEC,
            RData::NSEC3(..) => RecordType::NSEC3,
            RData::NSEC3PARAM(..) => RecordType::NSEC3PARAM,
            RData::NULL(..) => RecordType::NULL,
            RData::OPT(..) => RecordType::OPT,
            RData::PTR(..) => RecordType::PTR,
            RData::SIG(..) => RecordType::SIG,
            RData::SOA(..) => RecordType::SOA,
            RData::SRV(..) => RecordType::SRV,
            RData::TXT(..) => RecordType::TXT,
        }
    }
}

// TODO: this is kinda broken right now since it can't cover all types.
#[deprecated]
#[cfg(test)]
impl<'a> From<&'a RData> for RecordType {
    fn from(rdata: &'a RData) -> Self {
        match *rdata {
            RData::A(..) => RecordType::A,
            RData::AAAA(..) => RecordType::AAAA,
            RData::CNAME(..) => RecordType::CNAME,
            RData::DS(..) => RecordType::DS,
            RData::KEY(..) => RecordType::KEY,
            RData::DNSKEY(..) => RecordType::DNSKEY,
            RData::MX(..) => RecordType::MX,
            RData::NS(..) => RecordType::NS,
            RData::NSEC(..) => RecordType::NSEC,
            RData::NSEC3(..) => RecordType::NSEC3,
            RData::NSEC3PARAM(..) => RecordType::NSEC3PARAM,
            RData::NULL(..) => RecordType::NULL,
            RData::OPT(..) => RecordType::OPT,
            RData::PTR(..) => RecordType::PTR,
            RData::SIG(..) => RecordType::SIG,
            RData::SOA(..) => RecordType::SOA,
            RData::SRV(..) => RecordType::SRV,
            RData::TXT(..) => RecordType::TXT,
        }
    }
}

impl PartialOrd<RData> for RData {
    fn partial_cmp(&self, other: &RData) -> Option<Ordering> {
        Some(self.cmp(&other))
    }
}

impl Ord for RData {
    // RFC 4034                DNSSEC Resource Records               March 2005
    //
    // 6.3.  Canonical RR Ordering within an RRset
    //
    //    For the purposes of DNS security, RRs with the same owner name,
    //    class, and type are sorted by treating the RDATA portion of the
    //    canonical form of each RR as a left-justified unsigned octet sequence
    //    in which the absence of an octet sorts before a zero octet.
    //
    //    [RFC2181] specifies that an RRset is not allowed to contain duplicate
    //    records (multiple RRs with the same owner name, class, type, and
    //    RDATA).  Therefore, if an implementation detects duplicate RRs when
    //    putting the RRset in canonical form, it MUST treat this as a protocol
    //    error.  If the implementation chooses to handle this protocol error
    //    in the spirit of the robustness principle (being liberal in what it
    //    accepts), it MUST remove all but one of the duplicate RR(s) for the
    //    purposes of calculating the canonical form of the RRset.
    fn cmp(&self, other: &Self) -> Ordering {
        // TODO: how about we just store the bytes with the decoded data?
        //  the decoded data is useful for queries, the encoded data is needed for transfers, signing
        //  and ordering.
        self.to_bytes().cmp(&other.to_bytes())
    }
}

#[cfg(test)]
mod tests {
    use std::net::Ipv6Addr;
    use std::net::Ipv4Addr;
    use std::str::FromStr;

    use super::*;
    #[allow(unused)]
    use serialize::binary::*;
    use serialize::binary::bin_tests::test_emit_data_set;
    use rr::domain::Name;
    use rr::rdata::{MX, SOA, SRV, TXT};

    fn get_data() -> Vec<(RData, Vec<u8>)> {
        vec![
            (
                RData::CNAME(Name::from_labels(vec!["www", "example", "com"])),
                vec![
                    3,
                    b'w',
                    b'w',
                    b'w',
                    7,
                    b'e',
                    b'x',
                    b'a',
                    b'm',
                    b'p',
                    b'l',
                    b'e',
                    3,
                    b'c',
                    b'o',
                    b'm',
                    0,
                ]
            ),
            (
                RData::MX(MX::new(256, Name::from_labels(vec!["n"]))),
                vec![1, 0, 1, b'n', 0]
            ),
            (
                RData::NS(Name::from_labels(vec!["www", "example", "com"])),
                vec![
                    3,
                    b'w',
                    b'w',
                    b'w',
                    7,
                    b'e',
                    b'x',
                    b'a',
                    b'm',
                    b'p',
                    b'l',
                    b'e',
                    3,
                    b'c',
                    b'o',
                    b'm',
                    0,
                ]
            ),
            (
                RData::PTR(Name::from_labels(vec!["www", "example", "com"])),
                vec![
                    3,
                    b'w',
                    b'w',
                    b'w',
                    7,
                    b'e',
                    b'x',
                    b'a',
                    b'm',
                    b'p',
                    b'l',
                    b'e',
                    3,
                    b'c',
                    b'o',
                    b'm',
                    0,
                ]
            ),
            (
                RData::SOA(SOA::new(
                    Name::from_labels(vec!["www", "example", "com"]),
                    Name::from_labels(vec!["xxx", "example", "com"]),
                    u32::max_value(),
                    -1 as i32,
                    -1 as i32,
                    -1 as i32,
                    u32::max_value(),
                )),
                vec![
                    3,
                    b'w',
                    b'w',
                    b'w',
                    7,
                    b'e',
                    b'x',
                    b'a',
                    b'm',
                    b'p',
                    b'l',
                    b'e',
                    3,
                    b'c',
                    b'o',
                    b'm',
                    0,
                    3,
                    b'x',
                    b'x',
                    b'x',
                    0xC0,
                    0x04,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                    0xFF,
                ]
            ),
            (
                RData::TXT(TXT::new(vec![
                    "abcdef".to_string(),
                    "ghi".to_string(),
                    "".to_string(),
                    "j".to_string(),
                ])),
                vec![
                    6,
                    b'a',
                    b'b',
                    b'c',
                    b'd',
                    b'e',
                    b'f',
                    3,
                    b'g',
                    b'h',
                    b'i',
                    0,
                    1,
                    b'j',
                ]
            ),
            (
                RData::A(Ipv4Addr::from_str("0.0.0.0").unwrap()),
                vec![0, 0, 0, 0]
            ),
            (
                RData::AAAA(Ipv6Addr::from_str("::").unwrap()),
                vec![0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
            ),
            (
                RData::SRV(SRV::new(
                    1,
                    2,
                    3,
                    Name::from_labels(vec!["www", "example", "com"]),
                )),
                vec![
                    0x00,
                    0x01,
                    0x00,
                    0x02,
                    0x00,
                    0x03,
                    3,
                    b'w',
                    b'w',
                    b'w',
                    7,
                    b'e',
                    b'x',
                    b'a',
                    b'm',
                    b'p',
                    b'l',
                    b'e',
                    3,
                    b'c',
                    b'o',
                    b'm',
                    0,
                ]
            ),
        ]
    }

    // TODO this test kinda sucks, shows the problem with not storing the binary parts
    #[test]
    fn test_order() {
        let ordered: Vec<RData> =
            vec![
                RData::A(Ipv4Addr::from_str("0.0.0.0").unwrap()),
                RData::AAAA(Ipv6Addr::from_str("::").unwrap()),
                RData::SRV(SRV::new(
                    1,
                    2,
                    3,
                    Name::from_labels(vec!["www", "example", "com"]),
                )),
                RData::MX(MX::new(256, Name::from_labels(vec!["n"]))),
                RData::CNAME(Name::from_labels(vec!["www", "example", "com"])),
                RData::PTR(Name::from_labels(vec!["www", "example", "com"])),
                RData::NS(Name::from_labels(vec!["www", "example", "com"])),
                RData::SOA(SOA::new(
                    Name::from_labels(vec!["www", "example", "com"]),
                    Name::from_labels(vec!["xxx", "example", "com"]),
                    u32::max_value(),
                    -1 as i32,
                    -1 as i32,
                    -1 as i32,
                    u32::max_value(),
                )),
                RData::TXT(TXT::new(vec![
                    "abcdef".to_string(),
                    "ghi".to_string(),
                    "".to_string(),
                    "j".to_string(),
                ])),
            ];
        let mut unordered = vec![
            RData::CNAME(Name::from_labels(vec!["www", "example", "com"])),
            RData::MX(MX::new(256, Name::from_labels(vec!["n"]))),
            RData::PTR(Name::from_labels(vec!["www", "example", "com"])),
            RData::NS(Name::from_labels(vec!["www", "example", "com"])),
            RData::SOA(SOA::new(
                Name::from_labels(vec!["www", "example", "com"]),
                Name::from_labels(vec!["xxx", "example", "com"]),
                u32::max_value(),
                -1 as i32,
                -1 as i32,
                -1 as i32,
                u32::max_value(),
            )),
            RData::TXT(TXT::new(vec![
                "abcdef".to_string(),
                "ghi".to_string(),
                "".to_string(),
                "j".to_string(),
            ])),
            RData::A(Ipv4Addr::from_str("0.0.0.0").unwrap()),
            RData::AAAA(Ipv6Addr::from_str("::").unwrap()),
            RData::SRV(SRV::new(
                1,
                2,
                3,
                Name::from_labels(vec!["www", "example", "com"]),
            )),
        ];

        unordered.sort();
        assert_eq!(ordered, unordered);
    }

    #[test]
    fn test_read() {
        let mut test_pass = 0;
        for (expect, binary) in get_data() {
            test_pass += 1;
            println!("test {}: {:?}", test_pass, binary);
            let length = binary.len() as u16; // pre exclusive borrow
            let mut decoder = BinDecoder::new(&binary);

            assert_eq!(
                RData::read(
                    &mut decoder,
                    ::rr::record_type::RecordType::from(&expect),
                    length,
                ).unwrap(),
                expect
            );
        }
    }

    #[test]
    fn test_write_to() {
        test_emit_data_set(get_data(), |e, d| d.emit(e));
    }
}