Commit 4130f167 authored by louiz’'s avatar louiz’

Check for timeouts on the DNS resolution using c-ares

ref #3083
parent a42af9e7
......@@ -6,6 +6,8 @@
#include <network/dns_handler.hpp>
#include <network/poller.hpp>
#include <utils/timed_events.hpp>
#include <algorithm>
#include <stdexcept>
......@@ -30,7 +32,13 @@ DNSHandler::DNSHandler()
int ares_error;
if ((ares_error = ::ares_library_init(ARES_LIB_INIT_ALL)) != 0)
throw std::runtime_error("Failed to initialize c-ares lib: "s + ares_strerror(ares_error));
if ((ares_error = ::ares_init(&this->channel)) != ARES_SUCCESS)
struct ares_options options = {};
// The default timeout values are way too high
options.timeout = 1000;
options.tries = 3;
if ((ares_error = ::ares_init_options(&this->channel,
&options,
ARES_OPT_TIMEOUTMS|ARES_OPT_TRIES)) != ARES_SUCCESS)
throw std::runtime_error("Failed to initialize c-ares channel: "s + ares_strerror(ares_error));
}
......@@ -99,7 +107,8 @@ void DNSHandler::watch_dns_sockets(std::shared_ptr<Poller>& poller)
{ // If not found, create it because we need to watch it
if (it == this->socket_handlers.end())
{
this->socket_handlers.emplace_front(std::make_unique<DNSSocketHandler>(poller, i));
this->socket_handlers.emplace(this->socket_handlers.begin(),
std::make_unique<DNSSocketHandler>(poller, i));
it = this->socket_handlers.begin();
}
poller->add_socket_handler(it->get());
......@@ -107,6 +116,23 @@ void DNSHandler::watch_dns_sockets(std::shared_ptr<Poller>& poller)
poller->watch_send_events(it->get());
}
}
// Cancel previous timer, if any.
TimedEventsManager::instance().cancel("DNS timeout");
struct timeval tv;
struct timeval* tvp;
tvp = ::ares_timeout(this->channel, NULL, &tv);
if (tvp)
{
auto future_time = std::chrono::steady_clock::now() + std::chrono::seconds(tvp->tv_sec) + \
std::chrono::microseconds(tvp->tv_usec);
TimedEventsManager::instance().add_event(TimedEvent(std::move(future_time),
[this]()
{
for (auto& dns_socket_handler: this->socket_handlers)
dns_socket_handler->on_recv();
},
"DNS timeout"));
}
}
#endif /* CARES_FOUND */
......@@ -11,7 +11,7 @@ class DNSSocketHandler;
# include <ares.h>
# include <memory>
# include <string>
# include <list>
# include <vector>
void on_hostname4_resolved(void* arg, int status, int, struct hostent* hostent);
void on_hostname6_resolved(void* arg, int status, int, struct hostent* hostent);
......@@ -49,7 +49,7 @@ private:
* call to ares_fds. DNSSocketHandlers are added to it or removed from it
* in the watch_dns_sockets() method
*/
std::list<std::unique_ptr<DNSSocketHandler>> socket_handlers;
std::vector<std::unique_ptr<DNSSocketHandler>> socket_handlers;
ares_channel channel;
DNSHandler(const DNSHandler&) = delete;
......
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