[asio] Second connection fails

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

[asio] Second connection fails

Boost - Users mailing list
Hello,

I am using boost.asio to connect a self written host. The function below is called with acceptorRanks = {0, 1}. The
first connection went well, but the second one fails (to 1). It is always the second with, e.g. when called with {1, 0},
connecting to 0 fails.

I took the code out of context, changed some lines for clarity, I hope you can help me!

The sockets seems to connect, i.e. there is no error, but the asio::write fails with "Bad file descriptor"

Wireshark only shows traffic for the first connections, nothing at all the second (when filtered by port name). The
connection is always on localhost.

The host to wich I connect always takes on connection per process, that is way I think the problem is with the requester.

I would be really thankful for any help what the problem could be.

Best Thanks!
Florian


Same code: https://gist.github.com/floli/d418405ca50d722f1abf8bf5971466e2

void requestConnection(std::string      const &nameAcceptor,
                       std::string      const &nameRequester,
                       std::set<int>    const &acceptorRanks,
                       int                     requesterRank)

{
  boost::asio::ip::tcp::resolver resolver(*_ioService);

  for (auto const & acceptorRank : acceptorRanks) {
    try {
      address = readAddress(nameAcceptor, nameRequester, acceptorRank);
      DEBUG("Requesting connection to " << address);

      std::string ipAddress  = address.substr(0, address.find(":"));
      std::string portNumber = address.substr(ipAddress.length()+1, address.length() - ipAddress.length()-1);

      _portNumber = static_cast<unsigned short>(std::stoi(portNumber));

      PtrSocket socket(new Socket(*_ioService)); // shared_ptr to socket

      using asio::ip::tcp;

      tcp::resolver::query query(tcp::v4(), ipAddress, portNumber);

      while (not isConnected()) {
        tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
        boost::system::error_code error = asio::error::host_not_found;
        boost::asio::connect(*socket, endpoint_iterator, error);

        _isConnected = not error;

        if (not isConnected()) {
          // Wait a little, since after a couple of ten-thousand trials the system
          // seems to get confused and the requester connects wrongly to itself.
          boost::asio::deadline_timer timer(*_ioService, boost::posix_time::milliseconds(1));
          timer.wait();
        }
      }

      DEBUG("Requested connection to " << address << ", rank = " << acceptorRank);
      _sockets[acceptorRank] = socket;
      WARN("CHECKPOINT 1 FOR RANK " << acceptorRank);
      asio::write(*_sockets.at(acceptorRank), asio::buffer(&requesterRank, sizeof(int)));
      WARN("CHECKPOINT 2 FOR RANK " << acceptorRank); // reached only for acceptorRank=0
    } catch (std::exception &e) {
      ERROR("Requesting connection to " << address << " failed: " << e.what());
    }
  }
  // NOTE:
  // Keep IO service running so that it fires asynchronous handlers from another thread.
  _work   = PtrWork(new asio::io_service::work(*_ioService));
  _thread = std::thread([this]() { _ioService->run(); });
}
_______________________________________________
Boost-users mailing list
[hidden email]
https://lists.boost.org/mailman/listinfo.cgi/boost-users
Reply | Threaded
Open this post in threaded view
|

Re: [asio] Second connection fails

Boost - Users mailing list
On 19/06/2018 23:08, Florian Lindner wrote:
> The host to wich I connect always takes on connection per process,
> that is way I think the problem is with the requester.

If you are trying to connect to the same server twice, and it only
supports one active connection, it might either refuse a second
connection or close its previous connection in favour of the new one.

_______________________________________________
Boost-users mailing list
[hidden email]
https://lists.boost.org/mailman/listinfo.cgi/boost-users
Reply | Threaded
Open this post in threaded view
|

Re: [asio] Second connection fails

Boost - Users mailing list
In reply to this post by Boost - Users mailing list
Can you re-run your test code with handler tracking enabled and post the output? How to enable: https://www.boost.org/doc/libs/1_67_0/doc/html/boost_asio/overview/core/handler_tracking.html

On Tue, Jun 19, 2018, 07:16 Florian Lindner via Boost-users <[hidden email]> wrote:
Hello,

I am using boost.asio to connect a self written host. The function below is called with acceptorRanks = {0, 1}. The
first connection went well, but the second one fails (to 1). It is always the second with, e.g. when called with {1, 0},
connecting to 0 fails.

I took the code out of context, changed some lines for clarity, I hope you can help me!

The sockets seems to connect, i.e. there is no error, but the asio::write fails with "Bad file descriptor"

Wireshark only shows traffic for the first connections, nothing at all the second (when filtered by port name). The
connection is always on localhost.

The host to wich I connect always takes on connection per process, that is way I think the problem is with the requester.

I would be really thankful for any help what the problem could be.

Best Thanks!
Florian


Same code: https://gist.github.com/floli/d418405ca50d722f1abf8bf5971466e2

void requestConnection(std::string      const &nameAcceptor,
                       std::string      const &nameRequester,
                       std::set<int>    const &acceptorRanks,
                       int                     requesterRank)

{
  boost::asio::ip::tcp::resolver resolver(*_ioService);

  for (auto const & acceptorRank : acceptorRanks) {
    try {
      address = readAddress(nameAcceptor, nameRequester, acceptorRank);
      DEBUG("Requesting connection to " << address);

      std::string ipAddress  = address.substr(0, address.find(":"));
      std::string portNumber = address.substr(ipAddress.length()+1, address.length() - ipAddress.length()-1);

      _portNumber = static_cast<unsigned short>(std::stoi(portNumber));

      PtrSocket socket(new Socket(*_ioService)); // shared_ptr to socket

      using asio::ip::tcp;

      tcp::resolver::query query(tcp::v4(), ipAddress, portNumber);

      while (not isConnected()) {
        tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
        boost::system::error_code error = asio::error::host_not_found;
        boost::asio::connect(*socket, endpoint_iterator, error);

        _isConnected = not error;

        if (not isConnected()) {
          // Wait a little, since after a couple of ten-thousand trials the system
          // seems to get confused and the requester connects wrongly to itself.
          boost::asio::deadline_timer timer(*_ioService, boost::posix_time::milliseconds(1));
          timer.wait();
        }
      }

      DEBUG("Requested connection to " << address << ", rank = " << acceptorRank);
      _sockets[acceptorRank] = socket;
      WARN("CHECKPOINT 1 FOR RANK " << acceptorRank);
      asio::write(*_sockets.at(acceptorRank), asio::buffer(&requesterRank, sizeof(int)));
      WARN("CHECKPOINT 2 FOR RANK " << acceptorRank); // reached only for acceptorRank=0
    } catch (std::exception &e) {
      ERROR("Requesting connection to " << address << " failed: " << e.what());
    }
  }
  // NOTE:
  // Keep IO service running so that it fires asynchronous handlers from another thread.
  _work   = PtrWork(new asio::io_service::work(*_ioService));
  _thread = std::thread([this]() { _ioService->run(); });
}
_______________________________________________
Boost-users mailing list
[hidden email]
https://lists.boost.org/mailman/listinfo.cgi/boost-users

_______________________________________________
Boost-users mailing list
[hidden email]
https://lists.boost.org/mailman/listinfo.cgi/boost-users
Reply | Threaded
Open this post in threaded view
|

Re: [asio] Second connection fails

Boost - Users mailing list
Am 21.06.2018 um 05:01 schrieb William Jagels:
> Can you re-run your test code with handler tracking enabled and post the output? How to enable:
> https://www.boost.org/doc/libs/1_67_0/doc/html/boost_asio/overview/core/handler_tracking.html

Hey,

I already did, but it shows very little information for non-asnyc operations. Anyways, I managed to fix it yesterday and
it was my own stupid mistake, not related to boost asion.

Thanks a lot for your input!
Florian

>
> On Tue, Jun 19, 2018, 07:16 Florian Lindner via Boost-users <[hidden email]
> <mailto:[hidden email]>> wrote:
>
>     Hello,
>
>     I am using boost.asio to connect a self written host. The function below is called with acceptorRanks = {0, 1}. The
>     first connection went well, but the second one fails (to 1). It is always the second with, e.g. when called with {1, 0},
>     connecting to 0 fails.
>
>     I took the code out of context, changed some lines for clarity, I hope you can help me!
>
>     The sockets seems to connect, i.e. there is no error, but the asio::write fails with "Bad file descriptor"
>
>     Wireshark only shows traffic for the first connections, nothing at all the second (when filtered by port name). The
>     connection is always on localhost.
>
>     The host to wich I connect always takes on connection per process, that is way I think the problem is with the
>     requester.
>
>     I would be really thankful for any help what the problem could be.
>
>     Best Thanks!
>     Florian
>
>
>     Same code: https://gist.github.com/floli/d418405ca50d722f1abf8bf5971466e2
>
>     void requestConnection(std::string      const &nameAcceptor,
>                            std::string      const &nameRequester,
>                            std::set<int>    const &acceptorRanks,
>                            int                     requesterRank)
>
>     {
>       boost::asio::ip::tcp::resolver resolver(*_ioService);
>
>       for (auto const & acceptorRank : acceptorRanks) {
>         try {
>           address = readAddress(nameAcceptor, nameRequester, acceptorRank);
>           DEBUG("Requesting connection to " << address);
>
>           std::string ipAddress  = address.substr(0, address.find(":"));
>           std::string portNumber = address.substr(ipAddress.length()+1, address.length() - ipAddress.length()-1);
>
>           _portNumber = static_cast<unsigned short>(std::stoi(portNumber));
>
>           PtrSocket socket(new Socket(*_ioService)); // shared_ptr to socket
>
>           using asio::ip::tcp;
>
>           tcp::resolver::query query(tcp::v4(), ipAddress, portNumber);
>
>           while (not isConnected()) {
>             tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
>             boost::system::error_code error = asio::error::host_not_found;
>             boost::asio::connect(*socket, endpoint_iterator, error);
>
>             _isConnected = not error;
>
>             if (not isConnected()) {
>               // Wait a little, since after a couple of ten-thousand trials the system
>               // seems to get confused and the requester connects wrongly to itself.
>               boost::asio::deadline_timer timer(*_ioService, boost::posix_time::milliseconds(1));
>               timer.wait();
>             }
>           }
>
>           DEBUG("Requested connection to " << address << ", rank = " << acceptorRank);
>           _sockets[acceptorRank] = socket;
>           WARN("CHECKPOINT 1 FOR RANK " << acceptorRank);
>           asio::write(*_sockets.at <http://sockets.at>(acceptorRank), asio::buffer(&requesterRank, sizeof(int)));
>           WARN("CHECKPOINT 2 FOR RANK " << acceptorRank); // reached only for acceptorRank=0
>         } catch (std::exception &e) {
>           ERROR("Requesting connection to " << address << " failed: " << e.what());
>         }
>       }
>       // NOTE:
>       // Keep IO service running so that it fires asynchronous handlers from another thread.
>       _work   = PtrWork(new asio::io_service::work(*_ioService));
>       _thread = std::thread([this]() { _ioService->run(); });
>     }
>     _______________________________________________
>     Boost-users mailing list
>     [hidden email] <mailto:[hidden email]>
>     https://lists.boost.org/mailman/listinfo.cgi/boost-users
>
_______________________________________________
Boost-users mailing list
[hidden email]
https://lists.boost.org/mailman/listinfo.cgi/boost-users