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authorMartin Lucina <martin@lucina.net>2012-05-20 10:40:36 +0200
committerMartin Sustrik <sustrik@250bpm.com>2012-06-01 11:14:30 +0200
commit9ba8f9a503d69b891fae38628e0038f49ed5b8a4 (patch)
tree363d40593300c9665e7973680579d4c2b7647536 /src/udp_sender.cpp
parent58d54740785eb2c7208a01afb5bd9736e5808069 (diff)
UDP support
Signed-off-by: Martin Lucina <martin@lucina.net>
Diffstat (limited to 'src/udp_sender.cpp')
-rw-r--r--src/udp_sender.cpp197
1 files changed, 197 insertions, 0 deletions
diff --git a/src/udp_sender.cpp b/src/udp_sender.cpp
new file mode 100644
index 0000000..ddcffbb
--- /dev/null
+++ b/src/udp_sender.cpp
@@ -0,0 +1,197 @@
+/*
+ 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);
+}