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construct/include/ircd/net/resolver.h

91 lines
3.1 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_RESOLVER_H
// This file is not included with the IRCd standard include stack because
// it requires symbols we can't forward declare without boost headers. It
// is part of the <ircd/asio.h> stack which can be included in your
// definition file if you need low level access to this resolver API.
/// Internal resolver service
struct ircd::net::dns::resolver
{
struct tag;
using header = rfc1035::header;
static constexpr const size_t &MAX_COUNT{64};
static conf::item<milliseconds> timeout;
static conf::item<milliseconds> send_rate;
std::vector<ip::udp::endpoint> server; // The list of active servers
size_t server_next{0}; // Round-robin state to hit servers
void init_servers();
ctx::dock dock;
std::map<uint16_t, tag> tags; // The active requests
steady_point send_last; // Time of last send
using queued = std::pair<uint16_t, std::string>;
std::deque<queued> sendq; // Queue of frames for rate-limiting
ip::udp::socket ns; // A pollable activity object
ip::udp::endpoint reply_from; // Remote addr of recv
char reply[64_KiB] alignas(16); // Buffer for recv
bool handle_error(const error_code &ec) const;
bool handle_error(const header &, const rfc1035::question &, const dns::opts &);
void handle_reply(const header &, const const_buffer &body, tag &);
void handle_reply(const header &, const const_buffer &body);
void handle(const error_code &ec, const size_t &) noexcept;
void set_handle();
void queue_query(const const_buffer &, tag &);
void send_query(const ip::udp::endpoint &, const const_buffer &, tag &);
void send_query(const const_buffer &, tag &);
void submit(const const_buffer &, tag &);
tag &set_tag(tag &&);
const_buffer make_query(const mutable_buffer &buf, const tag &) const;
void operator()(const hostport &, const opts &, callback);
bool check_timeout(const uint16_t &id, tag &, const steady_point &expired);
void check_timeouts(const milliseconds &timeout);
void timeout_worker();
ctx::context timeout_context;
void flush(const queued &);
void sendq_worker();
ctx::context sendq_context;
resolver();
~resolver() noexcept;
};
struct ircd::net::dns::resolver::tag
{
uint16_t id {0};
hostport hp; // note: invalid after query sent
dns::opts opts; // note: invalid after query sent
callback cb;
steady_point last;
uint8_t tries {0};
tag(const hostport &, const dns::opts &, callback);
};
inline
ircd::net::dns::resolver::tag::tag(const hostport &hp,
const dns::opts &opts,
callback cb)
:hp{hp}
,opts{opts}
,cb{std::move(cb)}
{}