path: root/src/tcp_connecter.cpp

/*
    Copyright (c) 2007-2011 iMatix Corporation
    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file

    This file is part of 0MQ.

    0MQ is free software; you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    0MQ is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <new>
#include <string>

#include "tcp_connecter.hpp"
#include "tcp_engine.hpp"
#include "io_thread.hpp"
#include "platform.hpp"
#include "random.hpp"
#include "ip.hpp"
#include "err.hpp"

#if defined ZMQ_HAVE_WINDOWS
#include "windows.hpp"
#else
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <netdb.h>
#include <fcntl.h>
#ifdef ZMQ_HAVE_OPENVMS
#include <ioctl.h>
#endif
#endif

zmq::tcp_connecter_t::tcp_connecter_t (class io_thread_t *io_thread_,
      class session_t *session_, const options_t &options_,
      const char *address_, bool wait_) :
    own_t (io_thread_, options_),
    io_object_t (io_thread_),
    s (retired_fd),
    handle_valid (false),
    wait (wait_),
    session (session_),
    current_reconnect_ivl(options.reconnect_ivl)
{
    memset (&addr, 0, sizeof (addr));
    addr_len = 0;

    //  TODO: set_addess should be called separately, so that the error
    //  can be propagated.
    int rc = set_address (address_);
    zmq_assert (rc == 0);
}

zmq::tcp_connecter_t::~tcp_connecter_t ()
{
    if (wait)
        cancel_timer (reconnect_timer_id);
    if (handle_valid)
        rm_fd (handle);

    if (s != retired_fd)
        close ();
}

void zmq::tcp_connecter_t::process_plug ()
{
    if (wait)
        add_reconnect_timer();
    else
        start_connecting ();
}

void zmq::tcp_connecter_t::in_event ()
{
    //  We are not polling for incomming data, so we are actually called
    //  because of error here. However, we can get error on out event as well
    //  on some platforms, so we'll simply handle both events in the same way.
    out_event ();
}

void zmq::tcp_connecter_t::out_event ()
{
    fd_t fd = connect ();
    rm_fd (handle);
    handle_valid = false;

    //  Handle the error condition by attempt to reconnect.
    if (fd == retired_fd) {
        close ();
        wait = true;
        add_reconnect_timer();
        return;
    }

    //  Disable Nagle's algorithm. We are doing data batching on 0MQ level,
    //  so using Nagle wouldn't improve throughput in anyway, but it would
    //  hurt latency.
    int nodelay = 1;
    int rc = setsockopt (fd, IPPROTO_TCP, TCP_NODELAY, (char*) &nodelay,
        sizeof (int));
#ifdef ZMQ_HAVE_WINDOWS
    wsa_assert (rc != SOCKET_ERROR);
#else
    errno_assert (rc == 0);
#endif

#ifdef ZMQ_HAVE_OPENVMS
    //  Disable delayed acknowledgements as they hurt latency is serious manner.
    int nodelack = 1;
    rc = setsockopt (fd, IPPROTO_TCP, TCP_NODELACK, (char*) &nodelack,
        sizeof (int));
    errno_assert (rc != SOCKET_ERROR);
#endif

    //  Create the engine object for this connection.
    tcp_engine_t *engine = new (std::nothrow) tcp_engine_t (fd, options);
    alloc_assert (engine);

    //  Attach the engine to the corresponding session object.
    send_attach (session, engine);

    //  Shut the connecter down.
    terminate ();
}

void zmq::tcp_connecter_t::timer_event (int id_)
{
    zmq_assert (id_ == reconnect_timer_id);
    wait = false;
    start_connecting ();
}

void zmq::tcp_connecter_t::start_connecting ()
{
    //  Open the connecting socket.
    int rc = open ();

    //  Connect may succeed in synchronous manner.
    if (rc == 0) {
        handle = add_fd (s);
        handle_valid = true;
        out_event ();
        return;
    }

    //  Connection establishment may be dealyed. Poll for its completion.
    else if (rc == -1 && errno == EAGAIN) {
        handle = add_fd (s);
        handle_valid = true;
        set_pollout (handle);
        return;
    }

    //  Handle any other error condition by eventual reconnect.
    wait = true;
    add_reconnect_timer();
}

void zmq::tcp_connecter_t::add_reconnect_timer()
{
    add_timer (get_new_reconnect_ivl(), reconnect_timer_id);
}

int zmq::tcp_connecter_t::get_new_reconnect_ivl ()
{
    //  The new interval is the current interval + random value.
    int this_interval = current_reconnect_ivl +
        (generate_random () % options.reconnect_ivl);

    //  Only change the current reconnect interval  if the maximum reconnect
    //  interval was set and if it's larger than the reconnect interval.
    if (options.reconnect_ivl_max > 0 && 
        options.reconnect_ivl_max > options.reconnect_ivl) {

        //  Calculate the next interval
        current_reconnect_ivl = current_reconnect_ivl * 2;
        if(current_reconnect_ivl >= options.reconnect_ivl_max) {
            current_reconnect_ivl = options.reconnect_ivl_max;
        }   
    }
    return this_interval;
}

#ifdef ZMQ_HAVE_WINDOWS

int zmq::tcp_connecter_t::set_address (const char *addr_)
{
    return resolve_ip_hostname (&addr, &addr_len, addr_);
}

int zmq::tcp_connecter_t::open ()
{
    zmq_assert (s == retired_fd);

    //  Create the socket.
    s = socket (addr.ss_family, SOCK_STREAM, IPPROTO_TCP);
    if (s == INVALID_SOCKET) {
        wsa_error_to_errno ();
        return -1;
    }

    // Set to non-blocking mode.
    unsigned long argp = 1;
    int rc = ioctlsocket (s, FIONBIO, &argp);
    wsa_assert (rc != SOCKET_ERROR);

    //  Connect to the remote peer.
    rc = ::connect (s, (sockaddr*) &addr, addr_len);

    //  Connect was successfull immediately.
    if (rc == 0)
        return 0;

    //  Asynchronous connect was launched.
    if (rc == SOCKET_ERROR && (WSAGetLastError () == WSAEINPROGRESS ||
          WSAGetLastError () == WSAEWOULDBLOCK)) {
        errno = EAGAIN;
        return -1;
    }
    
    wsa_error_to_errno ();
    return -1;
}

int zmq::tcp_connecter_t::close ()
{
    zmq_assert (s != retired_fd);
    int rc = closesocket (s);
    wsa_assert (rc != SOCKET_ERROR);
    s = retired_fd;
    return 0;
}

zmq::fd_t zmq::tcp_connecter_t::connect ()
{
    //  Nonblocking connect have finished. Check whether an error occured.
    int err = 0;
    socklen_t len = sizeof err;
    int rc = getsockopt (s, SOL_SOCKET, SO_ERROR, (char*) &err, &len);
    zmq_assert (rc == 0);
    if (err != 0) {

        //  Assert that the error was caused by the networking problems
        //  rather than 0MQ bug.
        if (err == WSAECONNREFUSED || err == WSAETIMEDOUT ||
              err == WSAECONNABORTED || err == WSAEHOSTUNREACH ||
              err == WSAENETUNREACH || err == WSAENETDOWN)
            return retired_fd;

        wsa_assert_no (err);
    }

    //  Return the newly connected socket.
    fd_t result = s;
    s = retired_fd;
    return result;
}

#else

int zmq::tcp_connecter_t::set_address (const char *addr_)
{
    return resolve_ip_hostname (&addr, &addr_len, addr_);
}

int zmq::tcp_connecter_t::open ()
{
    zmq_assert (s == retired_fd);
    struct sockaddr *sa = (struct sockaddr*) &addr;

    if (AF_UNIX != sa->sa_family) {

        //  Create the socket.
        s = socket (sa->sa_family, SOCK_STREAM, IPPROTO_TCP);
        if (s == -1)
            return -1;

        // Set to non-blocking mode.
#ifdef ZMQ_HAVE_OPENVMS
    	int flags = 1;
    	int rc = ioctl (s, FIONBIO, &flags);
        errno_assert (rc != -1);
#else
    	int flags = fcntl (s, F_GETFL, 0);
    	if (flags == -1)
            flags = 0;
    	int rc = fcntl (s, F_SETFL, flags | O_NONBLOCK);
        errno_assert (rc != -1);
#endif

        //  Connect to the remote peer.
        rc = ::connect (s, (struct sockaddr*) &addr, addr_len);

        //  Connect was successfull immediately.
        if (rc == 0)
            return 0;

        //  Asynchronous connect was launched.
        if (rc == -1 && errno == EINPROGRESS) {
            errno = EAGAIN;
            return -1;
        }

        //  Error occured.
        int err = errno;
        close ();
        errno = err;
        return -1;
    }

#ifndef ZMQ_HAVE_OPENVMS
    else {

        //  Create the socket.
        zmq_assert (AF_UNIX == sa->sa_family);
        s = socket (AF_UNIX, SOCK_STREAM, 0);
        if (s == -1)
            return -1;

        //  Set the non-blocking flag.
        int flag = fcntl (s, F_GETFL, 0);
        if (flag == -1) 
            flag = 0;
        int rc = fcntl (s, F_SETFL, flag | O_NONBLOCK);
        errno_assert (rc != -1);

        //  Connect to the remote peer.
        rc = ::connect (s, (struct sockaddr*) &addr, sizeof (sockaddr_un));

        //  Connect was successfull immediately.
        if (rc == 0)
            return 0;

        //  Error occured.
        int err = errno;
        close ();
        errno = err;
        return -1;
    }
#endif

    zmq_assert (false);
    return -1;
}

int zmq::tcp_connecter_t::close ()
{
    zmq_assert (s != retired_fd);
    int rc = ::close (s);
    if (rc != 0)
        return -1;
    s = retired_fd;
    return 0;
}

zmq::fd_t zmq::tcp_connecter_t::connect ()
{
    //  Following code should handle both Berkeley-derived socket
    //  implementations and Solaris.
    int err = 0;
#if defined ZMQ_HAVE_HPUX
    int len = sizeof (err);
#else
    socklen_t len = sizeof (err);
#endif
    int rc = getsockopt (s, SOL_SOCKET, SO_ERROR, (char*) &err, &len);
    if (rc == -1)
        err = errno;
    if (err != 0) {

        //  Assert if the error was caused by 0MQ bug.
        //  Networking problems are OK. No need to assert.
        errno = err;
        errno_assert (errno == ECONNREFUSED || errno == ECONNRESET ||
            errno == ETIMEDOUT || errno == EHOSTUNREACH ||
            errno == ENETUNREACH || errno == ENETDOWN);

        return retired_fd;
    }

    fd_t result = s;
    s = retired_fd;
    return result;
}

#endif