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construct/modules/s_dns_resolver.h

96 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.
struct ircd::net::dns::resolver
{
struct tag;
using header = rfc1035::header;
static conf::item<std::string> servers;
static conf::item<milliseconds> timeout;
static conf::item<milliseconds> send_rate;
static conf::item<size_t> send_burst;
static conf::item<size_t> retry_max;
std::vector<ip::udp::endpoint> server; // The list of active servers
size_t server_next{0}; // Round-robin state to hit servers
ctx::dock dock;
std::map<uint16_t, tag> tags; // The active requests
steady_point send_last; // Time of last send
std::deque<uint16_t> sendq; // Queue of frames for rate-limiting
ip::udp::socket ns; // A pollable activity object
ip::udp::endpoint reply_from; // Remote addr of recv
unique_buffer<mutable_buffer> reply; // Buffer for recv
void add_server(const ipport &);
void set_servers(const string_view &list);
void set_servers();
bool handle_error(const error_code &ec) const;
bool handle_error(const header &, const rfc1035::question &, tag &);
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 send_query(const ip::udp::endpoint &, tag &);
void queue_query(tag &);
void send_query(tag &);
void submit(tag &);
template<class... A> tag &set_tag(A&&...);
static const_buffer make_query(const mutable_buffer &buf, const tag &);
void operator()(const hostport &, const opts &, callback &&);
void handle_post_error(const uint16_t id, tag &, const std::system_error &);
void post_error(tag &, const std::system_error &ec);
bool check_timeout(const uint16_t &id, tag &, const steady_point &expired);
void check_timeouts(const milliseconds &timeout);
void cancel_all_tags();
void timeout_worker();
ctx::context timeout_context;
void flush(const uint16_t &);
void sendq_work();
void sendq_clear();
void sendq_worker();
ctx::context sendq_context;
resolver();
~resolver() noexcept;
};
struct ircd::net::dns::resolver::tag
{
uint16_t id {0};
hostport hp;
dns::opts opts; // note: invalid after query sent
const_buffer question;
callback cb;
steady_point last {steady_point::min()};
uint8_t tries {0};
char hostbuf[256];
char qbuf[384];
tag(const hostport &, const dns::opts &, callback &&);
tag(tag &&) = delete;
tag(const tag &) = delete;
};
inline
ircd::net::dns::resolver::tag::tag(const hostport &hp,
const dns::opts &opts,
callback &&cb)
:hp{hp}
,opts{opts}
,cb{std::move(cb)}
{
this->hp.host = { hostbuf, copy(hostbuf, hp.host) };
}