119 lines
3.8 KiB
C++
119 lines
3.8 KiB
C++
/*
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* nghttp2 - HTTP/2 C Library
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*
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* Copyright (c) 2016 Tatsuhiro Tsujikawa
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef SHRPX_DNS_RESOLVER_H
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#define SHRPX_DNS_RESOLVER_H
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#include "shrpx.h"
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <vector>
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#include <ev.h>
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#include <ares.h>
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#include "template.h"
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#include "network.h"
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using namespace nghttp2;
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namespace shrpx {
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enum class DNSResolverStatus {
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// Resolver is in initial status
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IDLE,
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// Resolver is currently resolving host name
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RUNNING,
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// Resolver successfully resolved host name
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OK,
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// Resolver failed to resolve host name
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ERROR,
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};
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// Callback function called when host name lookup is finished.
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// |status| is either DNSResolverStatus::OK, or
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// DNSResolverStatus::ERROR. If |status| is DNSResolverStatus::OK,
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// |result| points to the resolved address. Note that port portion of
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// |result| is undefined, and must be initialized by application.
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// This callback function is not called if name lookup finishes in
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// DNSResolver::resolve() completely. In this case, application
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// should call DNSResolver::get_status() to get current status and
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// result. In other words, callback is called if get_status() returns
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// DNSResolverStatus::RUNNING.
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using CompleteCb =
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std::function<void(DNSResolverStatus status, const Address *result)>;
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// DNSResolver is asynchronous name resolver, backed by c-ares
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// library.
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class DNSResolver {
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public:
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DNSResolver(struct ev_loop *loop);
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~DNSResolver();
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// Starts resolving hostname |name|.
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int resolve(const StringRef &name, int family);
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// Returns status. If status_ is DNSResolverStatus::SUCCESS &&
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// |result| is not nullptr, |*result| is filled.
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DNSResolverStatus get_status(Address *result) const;
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// Sets callback function when name lookup finishes. The callback
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// function is called in a way that it can destroy this DNSResolver.
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void set_complete_cb(CompleteCb cb);
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CompleteCb get_complete_cb() const;
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// Calls these functions when read/write event occurred respectively.
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int on_read(int fd);
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int on_write(int fd);
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int on_timeout();
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// Calls this function when DNS query finished.
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void on_result(int status, hostent *hostent);
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void reset_timeout();
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void start_rev(int fd);
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void stop_rev(int fd);
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void start_wev(int fd);
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void stop_wev(int fd);
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private:
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int handle_event(int rfd, int wfd);
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std::vector<std::unique_ptr<ev_io>> revs_, wevs_;
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Address result_;
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CompleteCb completeCb_;
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ev_timer timer_;
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StringRef name_;
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struct ev_loop *loop_;
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// ares_channel is pointer type
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ares_channel channel_;
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// AF_INET or AF_INET6. AF_INET for A record lookup, and AF_INET6
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// for AAAA record lookup.
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int family_;
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DNSResolverStatus status_;
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};
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} // namespace shrpx
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#endif // SHRPX_DNS_RESOLVER_H
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