353 lines
8.4 KiB
C++
353 lines
8.4 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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#include "shrpx_dns_resolver.h"
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#include <cstring>
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#include <sys/time.h>
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#include "shrpx_log.h"
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#include "shrpx_connection.h"
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#include "shrpx_config.h"
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namespace shrpx {
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namespace {
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void sock_state_cb(void *data, int s, int read, int write) {
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auto resolv = static_cast<DNSResolver *>(data);
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if (resolv->get_status(nullptr) != DNS_STATUS_RUNNING) {
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return;
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}
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if (read) {
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resolv->start_rev(s);
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} else {
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resolv->stop_rev(s);
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}
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if (write) {
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resolv->start_wev(s);
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} else {
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resolv->stop_wev(s);
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}
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}
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} // namespace
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namespace {
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void host_cb(void *arg, int status, int timeouts, hostent *hostent) {
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auto resolv = static_cast<DNSResolver *>(arg);
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resolv->on_result(status, hostent);
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}
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} // namespace
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namespace {
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void process_result(DNSResolver *resolv) {
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auto cb = resolv->get_complete_cb();
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if (!cb) {
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return;
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}
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Address result;
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auto status = resolv->get_status(&result);
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switch (status) {
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case DNS_STATUS_OK:
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case DNS_STATUS_ERROR:
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cb(status, &result);
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break;
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}
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// resolv may be deleted here.
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}
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} // namespace
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namespace {
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void readcb(struct ev_loop *loop, ev_io *w, int revents) {
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auto resolv = static_cast<DNSResolver *>(w->data);
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resolv->on_read(w->fd);
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process_result(resolv);
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}
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} // namespace
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namespace {
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void writecb(struct ev_loop *loop, ev_io *w, int revents) {
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auto resolv = static_cast<DNSResolver *>(w->data);
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resolv->on_write(w->fd);
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process_result(resolv);
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}
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} // namespace
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namespace {
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void timeoutcb(struct ev_loop *loop, ev_timer *w, int revents) {
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auto resolv = static_cast<DNSResolver *>(w->data);
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resolv->on_timeout();
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process_result(resolv);
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}
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} // namespace
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namespace {
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void stop_ev(struct ev_loop *loop,
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const std::vector<std::unique_ptr<ev_io>> &evs) {
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for (auto &w : evs) {
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ev_io_stop(loop, w.get());
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}
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}
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} // namespace
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DNSResolver::DNSResolver(struct ev_loop *loop)
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: result_{},
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loop_(loop),
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channel_(nullptr),
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family_(AF_UNSPEC),
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status_(DNS_STATUS_IDLE) {
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ev_timer_init(&timer_, timeoutcb, 0., 0.);
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timer_.data = this;
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}
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DNSResolver::~DNSResolver() {
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if (channel_) {
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ares_destroy(channel_);
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}
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stop_ev(loop_, revs_);
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stop_ev(loop_, wevs_);
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ev_timer_stop(loop_, &timer_);
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}
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int DNSResolver::resolve(const StringRef &name, int family) {
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if (status_ != DNS_STATUS_IDLE) {
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return -1;
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}
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if (LOG_ENABLED(INFO)) {
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LOG(INFO) << "Start resolving host " << name << " in IPv"
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<< (family == AF_INET ? "4" : "6");
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}
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name_ = name;
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family_ = family;
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int rv;
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auto &dnsconf = get_config()->dns;
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ares_options opts{};
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opts.sock_state_cb = sock_state_cb;
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opts.sock_state_cb_data = this;
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opts.timeout = static_cast<int>(dnsconf.timeout.lookup * 1000);
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opts.tries = dnsconf.max_try;
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auto optmask = ARES_OPT_SOCK_STATE_CB | ARES_OPT_TIMEOUTMS | ARES_OPT_TRIES;
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ares_channel chan;
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rv = ares_init_options(&chan, &opts, optmask);
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if (rv != ARES_SUCCESS) {
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if (LOG_ENABLED(INFO)) {
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LOG(INFO) << "ares_init_options failed: " << ares_strerror(rv);
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}
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status_ = DNS_STATUS_ERROR;
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return -1;
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}
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channel_ = chan;
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status_ = DNS_STATUS_RUNNING;
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ares_gethostbyname(channel_, name_.c_str(), family_, host_cb, this);
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reset_timeout();
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return 0;
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}
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int DNSResolver::on_read(int fd) { return handle_event(fd, ARES_SOCKET_BAD); }
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int DNSResolver::on_write(int fd) { return handle_event(ARES_SOCKET_BAD, fd); }
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int DNSResolver::on_timeout() {
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return handle_event(ARES_SOCKET_BAD, ARES_SOCKET_BAD);
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}
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int DNSResolver::handle_event(int rfd, int wfd) {
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if (status_ == DNS_STATUS_IDLE) {
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return -1;
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}
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ares_process_fd(channel_, rfd, wfd);
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switch (status_) {
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case DNS_STATUS_RUNNING: {
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reset_timeout();
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return 0;
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}
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case DNS_STATUS_OK:
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return 0;
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case DNS_STATUS_ERROR:
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return -1;
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default:
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// Unreachable
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assert(0);
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abort();
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}
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}
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void DNSResolver::reset_timeout() {
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if (status_ != DNS_STATUS_RUNNING) {
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return;
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}
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timeval tvout;
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auto tv = ares_timeout(channel_, nullptr, &tvout);
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if (tv == nullptr) {
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return;
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}
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// To avoid that timer_.repeat becomes 0, which makes ev_timer_again
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// useless, add tiny fraction of time.
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timer_.repeat = tv->tv_sec + tv->tv_usec / 1000000. + 1e-9;
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ev_timer_again(loop_, &timer_);
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}
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int DNSResolver::get_status(Address *result) const {
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if (status_ != DNS_STATUS_OK) {
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return status_;
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}
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if (result) {
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memcpy(result, &result_, sizeof(result_));
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}
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return status_;
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}
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namespace {
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void start_ev(std::vector<std::unique_ptr<ev_io>> &evs, struct ev_loop *loop,
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int fd, int event, IOCb cb, void *data) {
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for (auto &w : evs) {
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if (w->fd == fd) {
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return;
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}
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}
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for (auto &w : evs) {
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if (w->fd == -1) {
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ev_io_set(w.get(), fd, event);
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ev_io_start(loop, w.get());
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return;
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}
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}
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auto w = make_unique<ev_io>();
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ev_io_init(w.get(), cb, fd, event);
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w->data = data;
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ev_io_start(loop, w.get());
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evs.emplace_back(std::move(w));
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}
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} // namespace
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namespace {
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void stop_ev(std::vector<std::unique_ptr<ev_io>> &evs, struct ev_loop *loop,
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int fd, int event) {
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for (auto &w : evs) {
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if (w->fd == fd) {
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ev_io_stop(loop, w.get());
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ev_io_set(w.get(), -1, event);
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return;
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}
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}
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}
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} // namespace
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void DNSResolver::start_rev(int fd) {
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start_ev(revs_, loop_, fd, EV_READ, readcb, this);
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}
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void DNSResolver::stop_rev(int fd) { stop_ev(revs_, loop_, fd, EV_READ); }
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void DNSResolver::start_wev(int fd) {
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start_ev(wevs_, loop_, fd, EV_WRITE, writecb, this);
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}
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void DNSResolver::stop_wev(int fd) { stop_ev(wevs_, loop_, fd, EV_WRITE); }
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void DNSResolver::on_result(int status, hostent *hostent) {
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stop_ev(loop_, revs_);
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stop_ev(loop_, wevs_);
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ev_timer_stop(loop_, &timer_);
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if (status != ARES_SUCCESS) {
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if (LOG_ENABLED(INFO)) {
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LOG(INFO) << "Name lookup for " << name_
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<< " failed: " << ares_strerror(status);
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}
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status_ = DNS_STATUS_ERROR;
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return;
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}
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auto ap = *hostent->h_addr_list;
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if (!ap) {
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if (LOG_ENABLED(INFO)) {
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LOG(INFO) << "Name lookup for " << name_ << "failed: no address returned";
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}
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status_ = DNS_STATUS_ERROR;
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return;
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}
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switch (hostent->h_addrtype) {
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case AF_INET:
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status_ = DNS_STATUS_OK;
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result_.len = sizeof(result_.su.in);
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result_.su.in = {};
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result_.su.in.sin_family = AF_INET;
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#ifdef HAVE_SOCKADDR_IN_SIN_LEN
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result_.su.in.sin_len = sizeof(result_.su.in);
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#endif // HAVE_SOCKADDR_IN_SIN_LEN
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memcpy(&result_.su.in.sin_addr, ap, sizeof(result_.su.in.sin_addr));
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break;
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case AF_INET6:
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status_ = DNS_STATUS_OK;
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result_.len = sizeof(result_.su.in6);
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result_.su.in6 = {};
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result_.su.in6.sin6_family = AF_INET6;
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#ifdef HAVE_SOCKADDR_IN6_SIN6_LEN
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result_.su.in6.sin6_len = sizeof(result_.su.in6);
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#endif // HAVE_SOCKADDR_IN6_SIN6_LEN
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memcpy(&result_.su.in6.sin6_addr, ap, sizeof(result_.su.in6.sin6_addr));
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break;
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default:
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assert(0);
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}
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if (status_ == DNS_STATUS_OK) {
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if (LOG_ENABLED(INFO)) {
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LOG(INFO) << "Name lookup succeeded: " << name_ << " -> "
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<< util::numeric_name(&result_.su.sa, result_.len);
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}
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return;
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}
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status_ = DNS_STATUS_ERROR;
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}
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void DNSResolver::set_complete_cb(CompleteCb cb) {
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completeCb_ = std::move(cb);
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}
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CompleteCb DNSResolver::get_complete_cb() const { return completeCb_; }
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} // namespace shrpx
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