construct/ircd/net_dns_cache.cc

// 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.

decltype(ircd::net::dns::cache::min_ttl)
ircd::net::dns::cache::min_ttl
{
	{ "name",     "ircd.net.dns.cache.min_ttl" },
	{ "default",  28800L                       },
};

decltype(ircd::net::dns::cache::error_ttl)
ircd::net::dns::cache::error_ttl
{
	{ "name",     "ircd.net.dns.cache.error_ttl" },
	{ "default",  1200L                          },
};

decltype(ircd::net::dns::cache::nxdomain_ttl)
ircd::net::dns::cache::nxdomain_ttl
{
	{ "name",     "ircd.net.dns.cache.nxdomain_ttl" },
	{ "default",  86400L                            },
};

decltype(ircd::net::dns::cache::waiting)
ircd::net::dns::cache::waiting;

decltype(ircd::net::dns::cache::mutex)
ircd::net::dns::cache::mutex;

decltype(ircd::net::dns::cache::dock)
ircd::net::dns::cache::dock;

bool
ircd::net::dns::cache::put(const hostport &h,
                           const opts &o,
                           const uint &r,
                           const string_view &m)
try
{
	using prototype = bool (const hostport &, const opts &, const uint &, const string_view &);

	static mods::import<prototype> call
	{
		"net_dns_cache", "ircd::net::dns::cache::put"
	};

	return call(h, o, r, m);
}
catch(const mods::unavailable &e)
{
	thread_local char buf[rfc1035::NAME_BUFSIZE];
	log::dwarning
	{
		log, "Failed to put error for '%s' in DNS cache :%s",
		string(buf, h),
		e.what()
	};

	return false;
}

bool
ircd::net::dns::cache::put(const hostport &h,
                           const opts &o,
                           const records &r)
try
{
	using prototype = bool (const hostport &, const opts &, const records &);

	static mods::import<prototype> call
	{
		"net_dns_cache", "ircd::net::dns::cache::put"
	};

	return call(h, o, r);
}
catch(const mods::unavailable &e)
{
	thread_local char buf[rfc1035::NAME_BUFSIZE];
	log::dwarning
	{
		log, "Failed to put '%s' in DNS cache :%s",
		string(buf, h),
		e.what()
	};

	return false;
}

/// This function has an opportunity to respond from the DNS cache. If it
/// returns true, that indicates it responded by calling back the user and
/// nothing further should be done for them. If it returns false, that
/// indicates it did not respond and to proceed normally. The response can
/// be of a cached successful result, or a cached error. Both will return
/// true.
bool
ircd::net::dns::cache::get(const hostport &h,
                           const opts &o,
                           const callback &c)
try
{
	using prototype = bool (const hostport &, const opts &, const callback &);

	static mods::import<prototype> call
	{
		"net_dns_cache", "ircd::net::dns::cache::get"
	};

	return call(h, o, c);
}
catch(const mods::unavailable &e)
{
	thread_local char buf[rfc1035::NAME_BUFSIZE];
	log::dwarning
	{
		log, "Failed to get '%s' from DNS cache :%s",
		string(buf, h),
		e.what()
	};

	return false;
}

bool
ircd::net::dns::cache::for_each(const hostport &h,
                                const opts &o,
                                const closure &c)
{
	using prototype = bool (const hostport &, const opts &, const closure &);

	static mods::import<prototype> call
	{
		"net_dns_cache", "ircd::net::dns::cache::for_each"
	};

	return call(h, o, c);
}

bool
ircd::net::dns::cache::for_each(const string_view &type,
                                const closure &c)
{
	using prototype = bool (const string_view &, const closure &);

	static mods::import<prototype> call
	{
		"net_dns_cache", "ircd::net::dns::cache::for_each"
	};

	return call(type, c);
}

ircd::string_view
ircd::net::dns::cache::make_type(const mutable_buffer &out,
                                 const uint16_t &type)
try
{
	return make_type(out, rfc1035::rqtype.at(type));
}
catch(const std::out_of_range &)
{
	throw error
	{
		"Record type[%u] is not recognized", type
	};
}

ircd::string_view
ircd::net::dns::cache::make_type(const mutable_buffer &out,
                                 const string_view &type)
{
	return fmt::sprintf
	{
		out, "ircd.dns.rrs.%s", type
	};
}

//
// cache::waiter
//

bool
ircd::net::dns::cache::operator==(const waiter &a, const waiter &b)
noexcept
{
	return
	a.opts.qtype == b.opts.qtype &&
	a.key && b.key &&
	a.key == b.key;
}

bool
ircd::net::dns::cache::operator!=(const waiter &a, const waiter &b)
noexcept
{
	return !operator==(a, b);
}

//
// cache::waiter::waiter
//

ircd::net::dns::cache::waiter::waiter(const hostport &hp,
                                      const dns::opts &opts,
                                      dns::callback &&callback)
:callback
{
	std::move(callback)
}
,opts
{
	opts
}
,port
{
	net::port(hp)
}
,key
{
	opts.qtype == 33?
		make_SRV_key(keybuf, hp, opts):
		strlcpy(keybuf, host(hp))
}
{
	this->opts.srv = {};
	this->opts.proto = {};
	assert(this->opts.qtype);
}