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construct/include/ircd/net/dns.h

72 lines
2.5 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// 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 is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_NET_DNS_H
namespace ircd::net
{
struct dns extern dns;
}
/// DNS resolution suite.
///
/// This is a singleton class; public usage is to make calls on the singleton
/// object like `ircd::net::dns()` etc.
///
struct ircd::net::dns
{
struct opts;
struct resolver;
struct resolver static *resolver;
struct opts static const opts_default;
public:
using callback = std::function<void (std::exception_ptr, vector_view<const rfc1035::record *>)>;
using callback_A_one = std::function<void (std::exception_ptr, const rfc1035::record::A &)>;
using callback_SRV_one = std::function<void (std::exception_ptr, const rfc1035::record::SRV &)>;
using callback_ipport_one = std::function<void (std::exception_ptr, const ipport &)>;
// Callback-based interface
void operator()(const hostport &, const opts &, callback);
void operator()(const hostport &, const opts &, callback_A_one);
void operator()(const hostport &, const opts &, callback_SRV_one);
void operator()(const hostport &, const opts &, callback_ipport_one);
// Callback-based interface (default options)
template<class Callback> void operator()(const hostport &, Callback&&);
};
/// DNS resolution options
struct ircd::net::dns::opts
{
/// Overrides the SRV query to make for this resolution. If empty an
/// SRV query may still be made from other deductions. This string is
/// copied at the start of the resolution. It must be a fully qualified
/// SRV query string: Example: "_matrix._tcp."
string_view srv;
/// Specifies the SRV protocol part when deducing the SRV query to be
/// made. This is used when the net::hostport.service string is just
/// the name of the service like "matrix" so we then use this value
/// to build the protocol part of the SRV query string. It is ignored
/// if `srv` is set or if no service is specified (thus no SRV query is
/// made in the first place).
string_view proto{"tcp"};
};
template<class Callback>
void
ircd::net::dns::operator()(const hostport &hostport,
Callback&& callback)
{
operator()(hostport, opts_default, std::forward<Callback>(callback));
}