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/*
Copyright (c) 2012 Martin Lucina <martin@lucina.net>
This file is part of Crossroads I/O.
Crossroads I/O 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.
Crossroads I/O 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 "platform.hpp"
#include <stdlib.h>
#include "io_thread.hpp"
#include "udp_sender.hpp"
#include "session_base.hpp"
#include "err.hpp"
#include "wire.hpp"
#include "stdint.hpp"
#include "ip.hpp"
xs::udp_sender_t::udp_sender_t (io_thread_t *parent_,
const options_t &options_) :
io_object_t (parent_),
options (options_),
encoder (0),
seq_no (1),
backoff_timer (NULL)
{
}
xs::udp_sender_t::~udp_sender_t ()
{
if (backoff_timer) {
rm_timer (backoff_timer);
}
}
int xs::udp_sender_t::init (const char *address_)
{
int rc;
rc = address_resolve_tcp (&address, address_, false, options.ipv4only);
if (rc != 0)
return rc;
// Create a connected UDP socket for a single peer, and make
// it non-blocking.
socket = open_socket (address.ss_family, SOCK_DGRAM, IPPROTO_UDP);
if (socket == -1)
return -1;
rc = ::connect (socket, (const sockaddr *)&address,
address_size (&address));
if (rc != 0)
return -1;
unblock_socket (socket);
return 0;
}
void xs::udp_sender_t::plug (io_thread_t *io_thread_, session_base_t *session_)
{
session = session_;
encoder.set_session (session);
// Start polling.
socket_handle = add_fd (socket);
set_pollout (socket_handle);
// UDP cannot pass subscriptions upstream; for now just fake subscribing
// to all messages.
msg_t msg;
msg.init_size (1);
*(unsigned char*) msg.data () = 1;
int rc = session_->write (&msg);
errno_assert (rc == 0);
session_->flush ();
}
void xs::udp_sender_t::unplug ()
{
rm_fd (socket_handle);
session = NULL;
}
void xs::udp_sender_t::terminate ()
{
unplug ();
delete this;
}
// Called when our pipe is reactivated (has more data for us).
void xs::udp_sender_t::activate_out ()
{
// Reactivate polling.
set_pollout (socket_handle);
// Try and send more data.
out_event (retired_fd);
}
void xs::udp_sender_t::activate_in ()
{
xs_assert (false);
}
// Called when POLLERR is fired on the socket.
void xs::udp_sender_t::in_event (fd_t fd_)
{
// Get the actual error code from the socket.
int err = 0;
socklen_t len = sizeof (err);
int rc = getsockopt (socket, SOL_SOCKET, SO_ERROR, (char *) &err, &len);
errno_assert (rc == 0);
// If we got ECONNREFUSED, there is no one on the other end.
// Stop sending for XS_RECONNECT_IVL milliseconds.
if (err == ECONNREFUSED) {
backoff_timer = add_timer (options.reconnect_ivl);
// Polling will be re-started by timer_event ().
reset_pollout (socket_handle);
return;
}
// Any other error is a bug, for now.
errno = err;
errno_assert (false);
}
// Called when POLLOUT is fired on the socket.
void xs::udp_sender_t::out_event (fd_t fd_)
{
unsigned char *data_p = data;
size_t size = pgm_max_tpdu - udp_header_size;
int offset = 0;
// Get one packet of data from the encoder.
encoder.get_data (&data_p, &size, &offset);
// If there is no data in the pipe
if (size == 0) {
// Stop polling, we will be re-started by activate_out ().
reset_pollout (socket_handle);
return;
}
assert ((size + udp_header_size) <= pgm_max_tpdu);
// Prepare UDP header (seqno, offset).
unsigned char udp_header [udp_header_size];
put_uint32 (udp_header, seq_no);
put_uint16 (udp_header + 4, (uint16_t) offset);
// Send out the message, ensuring the whole message was sent.
struct iovec iov[2] = {
{ udp_header, udp_header_size },
{ data_p, size }
};
ssize_t write_bytes = writev (socket, iov, 2);
// If we got ECONNREFUSED, there is no one on the other end.
// Drop the packet and back off for XS_RECONNECT_IVL milliseconds.
if (write_bytes == -1 && errno == ECONNREFUSED) {
backoff_timer = add_timer (options.reconnect_ivl);
// Polling will be re-started by timer_event ().
reset_pollout (socket_handle);
// Increase sequence number to ensure other end is notified of
// dropped packet.
++seq_no;
return;
}
errno_assert (write_bytes > 0);
assert ((size_t)write_bytes == (udp_header_size + size));
// Packet was sent successfully, increase sequence number.
++seq_no;
}
// Called when our backoff timer expires.
void xs::udp_sender_t::timer_event (handle_t handle_)
{
xs_assert (handle_ == backoff_timer);
backoff_timer = NULL;
// Re-start polling.
set_pollout (socket_handle);
out_event (retired_fd);
}
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