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Diffstat (limited to 'src/tcp_engine.cpp')
| -rw-r--r-- | src/tcp_engine.cpp | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/src/tcp_engine.cpp b/src/tcp_engine.cpp new file mode 100644 index 0000000..1972809 --- /dev/null +++ b/src/tcp_engine.cpp @@ -0,0 +1,401 @@ +/* + 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 "platform.hpp" +#if defined ZMQ_HAVE_WINDOWS +#include "windows.hpp" +#else +#include <unistd.h> +#include <sys/socket.h> +#include <arpa/inet.h> +#include <netinet/tcp.h> +#include <netinet/in.h> +#include <netdb.h> +#include <fcntl.h> +#endif + +#include <string.h> +#include <new> + +#include "tcp_engine.hpp" +#include "io_thread.hpp" +#include "session.hpp" +#include "config.hpp" +#include "err.hpp" + +zmq::tcp_engine_t::tcp_engine_t (fd_t fd_, const options_t &options_) : + s (retired_fd), + inpos (NULL), + insize (0), + decoder (in_batch_size, options_.maxmsgsize), + outpos (NULL), + outsize (0), + encoder (out_batch_size), + session (NULL), + leftover_session (NULL), + options (options_), + plugged (false) +{ + // Initialise the underlying socket. + int rc = open (fd_, options.sndbuf, options.rcvbuf); + zmq_assert (rc == 0); +} + +zmq::tcp_engine_t::~tcp_engine_t () +{ + zmq_assert (!plugged); + + if (s != retired_fd) + close (); +} + +void zmq::tcp_engine_t::plug (io_thread_t *io_thread_, session_t *session_) +{ + zmq_assert (!plugged); + plugged = true; + leftover_session = NULL; + + // Connect to session object. + zmq_assert (!session); + zmq_assert (session_); + encoder.set_session (session_); + decoder.set_session (session_); + session = session_; + + // Connect to I/O threads poller object. + io_object_t::plug (io_thread_); + handle = add_fd (s); + set_pollin (handle); + set_pollout (handle); + + // Flush all the data that may have been already received downstream. + in_event (); +} + +void zmq::tcp_engine_t::unplug () +{ + zmq_assert (plugged); + plugged = false; + + // Cancel all fd subscriptions. + rm_fd (handle); + + // Disconnect from I/O threads poller object. + io_object_t::unplug (); + + // Disconnect from session object. + encoder.set_session (NULL); + decoder.set_session (NULL); + leftover_session = session; + session = NULL; +} + +void zmq::tcp_engine_t::terminate () +{ + unplug (); + delete this; +} + +void zmq::tcp_engine_t::in_event () +{ + bool disconnection = false; + + // If there's no data to process in the buffer... + if (!insize) { + + // Retrieve the buffer and read as much data as possible. + // Note that buffer can be arbitrarily large. However, we assume + // the underlying TCP layer has fixed buffer size and thus the + // number of bytes read will be always limited. + decoder.get_buffer (&inpos, &insize); + insize = read (inpos, insize); + + // Check whether the peer has closed the connection. + if (insize == (size_t) -1) { + insize = 0; + disconnection = true; + } + } + + // Push the data to the decoder. + size_t processed = decoder.process_buffer (inpos, insize); + + if (unlikely (processed == (size_t) -1)) { + disconnection = true; + } + else { + + // Stop polling for input if we got stuck. + if (processed < insize) { + + // This may happen if queue limits are in effect. + if (plugged) + reset_pollin (handle); + } + + // Adjust the buffer. + inpos += processed; + insize -= processed; + } + + // Flush all messages the decoder may have produced. + // If IO handler has unplugged engine, flush transient IO handler. + if (unlikely (!plugged)) { + zmq_assert (leftover_session); + leftover_session->flush (); + } else { + session->flush (); + } + + if (session && disconnection) + error (); +} + +void zmq::tcp_engine_t::out_event () +{ + // If write buffer is empty, try to read new data from the encoder. + if (!outsize) { + + outpos = NULL; + encoder.get_data (&outpos, &outsize); + + // If IO handler has unplugged engine, flush transient IO handler. + if (unlikely (!plugged)) { + zmq_assert (leftover_session); + leftover_session->flush (); + return; + } + + // If there is no data to send, stop polling for output. + if (outsize == 0) { + reset_pollout (handle); + return; + } + } + + // If there are any data to write in write buffer, write as much as + // possible to the socket. Note that amount of data to write can be + // arbitratily large. However, we assume that underlying TCP layer has + // limited transmission buffer and thus the actual number of bytes + // written should be reasonably modest. + int nbytes = write (outpos, outsize); + + // Handle problems with the connection. + if (nbytes == -1) { + error (); + return; + } + + outpos += nbytes; + outsize -= nbytes; +} + +void zmq::tcp_engine_t::activate_out () +{ + set_pollout (handle); + + // Speculative write: The assumption is that at the moment new message + // was sent by the user the socket is probably available for writing. + // Thus we try to write the data to socket avoiding polling for POLLOUT. + // Consequently, the latency should be better in request/reply scenarios. + out_event (); +} + +void zmq::tcp_engine_t::activate_in () +{ + set_pollin (handle); + + // Speculative read. + in_event (); +} + +void zmq::tcp_engine_t::error () +{ + zmq_assert (session); + session->detach (); + unplug (); + delete this; +} + +#ifdef ZMQ_HAVE_WINDOWS + +int zmq::tcp_engine_t::open (fd_t fd_, int sndbuf_, int rcvbuf_) +{ + zmq_assert (s == retired_fd); + s = fd_; + + if (sndbuf_) { + int rc = setsockopt (s, SOL_SOCKET, SO_SNDBUF, + (char*) &sndbuf_, sizeof (int)); + errno_assert (rc == 0); + } + + if (rcvbuf_) { + int rc = setsockopt (s, SOL_SOCKET, SO_RCVBUF, + (char*) &rcvbuf_, sizeof (int)); + errno_assert (rc == 0); + } + + return 0; +} + +int zmq::tcp_engine_t::close () +{ + zmq_assert (s != retired_fd); + int rc = closesocket (s); + wsa_assert (rc != SOCKET_ERROR); + s = retired_fd; + return 0; +} + +int zmq::tcp_engine_t::write (const void *data_, size_t size_) +{ + int nbytes = send (s, (char*) data_, (int) size_, 0); + + // If not a single byte can be written to the socket in non-blocking mode + // we'll get an error (this may happen during the speculative write). + if (nbytes == SOCKET_ERROR && WSAGetLastError () == WSAEWOULDBLOCK) + return 0; + + // Signalise peer failure. + if (nbytes == -1 && ( + WSAGetLastError () == WSAENETDOWN || + WSAGetLastError () == WSAENETRESET || + WSAGetLastError () == WSAEHOSTUNREACH || + WSAGetLastError () == WSAECONNABORTED || + WSAGetLastError () == WSAETIMEDOUT || + WSAGetLastError () == WSAECONNRESET)) + return -1; + + wsa_assert (nbytes != SOCKET_ERROR); + + return (size_t) nbytes; +} + +int zmq::tcp_engine_t::read (void *data_, size_t size_) +{ + int nbytes = recv (s, (char*) data_, (int) size_, 0); + + // If not a single byte can be read from the socket in non-blocking mode + // we'll get an error (this may happen during the speculative read). + if (nbytes == SOCKET_ERROR && WSAGetLastError () == WSAEWOULDBLOCK) + return 0; + + // Connection failure. + if (nbytes == -1 && ( + WSAGetLastError () == WSAENETDOWN || + WSAGetLastError () == WSAENETRESET || + WSAGetLastError () == WSAECONNABORTED || + WSAGetLastError () == WSAETIMEDOUT || + WSAGetLastError () == WSAECONNRESET || + WSAGetLastError () == WSAECONNREFUSED || + WSAGetLastError () == WSAENOTCONN)) + return -1; + + wsa_assert (nbytes != SOCKET_ERROR); + + // Orderly shutdown by the other peer. + if (nbytes == 0) + return -1; + + return (size_t) nbytes; +} + +#else + +int zmq::tcp_engine_t::open (fd_t fd_, int sndbuf_, int rcvbuf_) +{ + assert (s == retired_fd); + s = fd_; + + if (sndbuf_) { + int rc = setsockopt (s, SOL_SOCKET, SO_SNDBUF, &sndbuf_, sizeof (int)); + errno_assert (rc == 0); + } + + if (rcvbuf_) { + int rc = setsockopt (s, SOL_SOCKET, SO_RCVBUF, &rcvbuf_, sizeof (int)); + errno_assert (rc == 0); + } + +#if defined ZMQ_HAVE_OSX || defined ZMQ_HAVE_FREEBSD + int set = 1; + int rc = setsockopt (s, SOL_SOCKET, SO_NOSIGPIPE, &set, sizeof (int)); + errno_assert (rc == 0); +#endif + + return 0; +} + +int zmq::tcp_engine_t::close () +{ + zmq_assert (s != retired_fd); + int rc = ::close (s); + if (rc != 0) + return -1; + s = retired_fd; + return 0; +} + +int zmq::tcp_engine_t::write (const void *data_, size_t size_) +{ + ssize_t nbytes = send (s, data_, size_, 0); + + // Several errors are OK. When speculative write is being done we may not + // be able to write a single byte to the socket. Also, SIGSTOP issued + // by a debugging tool can result in EINTR error. + if (nbytes == -1 && (errno == EAGAIN || errno == EWOULDBLOCK || + errno == EINTR)) + return 0; + + // Signalise peer failure. + if (nbytes == -1 && (errno == ECONNRESET || errno == EPIPE)) + return -1; + + errno_assert (nbytes != -1); + return (size_t) nbytes; +} + +int zmq::tcp_engine_t::read (void *data_, size_t size_) +{ + ssize_t nbytes = recv (s, data_, size_, 0); + + // Several errors are OK. When speculative read is being done we may not + // be able to read a single byte to the socket. Also, SIGSTOP issued + // by a debugging tool can result in EINTR error. + if (nbytes == -1 && (errno == EAGAIN || errno == EWOULDBLOCK || + errno == EINTR)) + return 0; + + // Signalise peer failure. + if (nbytes == -1 && (errno == ECONNRESET || errno == ECONNREFUSED || + errno == ETIMEDOUT || errno == EHOSTUNREACH)) + return -1; + + errno_assert (nbytes != -1); + + // Orderly shutdown by the peer. + if (nbytes == 0) + return -1; + + return (size_t) nbytes; +} + +#endif |