mirror of
https://github.com/matrix-construct/construct
synced 2024-07-03 17:28:18 +02:00
126 lines
4.5 KiB
C++
126 lines
4.5 KiB
C++
// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies.
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//
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// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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// IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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#pragma once
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#define HAVE_IRCD_RFC1035_H
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/// RFC 1035 (Nov. 1987)
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///
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namespace ircd::rfc1035
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{
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IRCD_EXCEPTION(ircd::error, error)
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struct header;
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struct question;
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struct answer;
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enum class op :uint8_t;
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extern const std::array<string_view, 25> rcode;
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extern const std::unordered_map<string_view, uint16_t> qtype;
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mutable_buffer make_query(const mutable_buffer &, const header &, const vector_view<const question> &);
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mutable_buffer make_query(const mutable_buffer &, const vector_view<const question> &);
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mutable_buffer make_query(const mutable_buffer &, const question &);
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}
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/// Helper class to construct a question. An object is constructed with a
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/// fully qualified domain string and the query type (qtype). At the
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/// appropriate time we will call operator() which prints a properly binary-
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/// formatted question for the question section in a DNS query; generally the
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/// user does not need to do this.
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///
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/// Note that each part of the fqdn cannot be longer than 63 characters. The
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/// supplied buffer must be large enough to hold the output, which is about
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/// the length of the fqdn + 6 bytes. The qtype can be specified as a string
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/// i.e "A" or "PTR" and it will be translated into the protocol number for
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/// you in the constructor.
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///
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struct ircd::rfc1035::question
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{
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string_view fqdn;
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uint16_t qtype;
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uint16_t qclass {0x01};
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/// Composes the question into buffer, returns used portion
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mutable_buffer operator()(const mutable_buffer &) const;
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/// Trivial constructor; supply fully qualified domain name and query type
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question(const string_view &fqdn, const uint16_t &qtype = 0x01) // "A"
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:fqdn{fqdn}
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,qtype{qtype}
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{}
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/// Supply fully qualified domain name and name of query type i.e "A"
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question(const string_view &fqdn, const string_view &qtype)
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:fqdn{fqdn}
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,qtype{rfc1035::qtype.at(qtype)}
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{}
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};
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struct ircd::rfc1035::answer
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{
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uint16_t qtype;
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uint16_t qclass;
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uint32_t ttl;
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uint16_t rdlength;
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const_raw_buffer rdata;
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char name[256];
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answer(const const_raw_buffer &);
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};
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/// Direct representation of the DNS header. This is laid out for
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/// little-endian platforms only. The uint16_t's are still big-endian and
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/// must be bswap()'ed.
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///
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struct ircd::rfc1035::header
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{
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uint16_t id; ///< query identification number
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uint8_t rd:1; ///< 0 = recursion not desired; 1 = desired
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uint8_t tc:1; ///< 0 = not-truncated; 1 = 512 bytes of reply only
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uint8_t aa:1; ///< 0 = non-authoritative; 1 = authoritative
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uint8_t opcode:4; ///< purpose of message
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uint8_t qr:1; ///< 0 = query; 1 = respnse
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uint8_t rcode:4; ///< response code
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uint8_t cd:1; ///< checking disabled by resolver
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uint8_t ad:1; ///< authentic data from named
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uint8_t unused:1; ///< unused bits (MBZ as of 4.9.3a3)
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uint8_t ra:1; ///< 1 = recursion available
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uint16_t qdcount; ///< number of question entries
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uint16_t ancount; ///< number of answer entries
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uint16_t nscount; ///< number of authority entries
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uint16_t arcount; ///< number of resource entries
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}
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__attribute__((packed));
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static_assert
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(
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sizeof(ircd::rfc1035::header) == 12,
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"The RFC1035 header is not the right size in this environment"
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);
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enum class ircd::rfc1035::op
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:uint8_t
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{
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QUERY = 0, ///< Query [RFC 1035]
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IQUERY = 1, ///< Inverse Query [RFC 1035, RFC 3425]
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STATUS = 2, ///< Server status request [RFC 1035]
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NOTIFY = 4, ///< Notify [RFC 1996]
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UPDATE = 5, ///< Update [RFC 2136]
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};
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