57b0cdf152
We must ensure we don't get flooded with ping replies if the outbound channel is slow. Currently we do this by keeping the ping reply in a separate temporary buffer and only writing it if the encoutput buffer is completely empty. This is overly pessimistic, as it is reasonable to add a ping reply to the encoutput buffer even if it has previous data in it, as long as that previous data doesn't include a ping reply. To track this better, put the ping reply directly into the encoutput buffer, and then record the size of encoutput at this time in pong_remain. As we write encoutput to the underlying channel, we can decrement the pong_remain counter. Once it hits zero, we can accept further ping replies for transmission. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
111 lines
3.4 KiB
C
111 lines
3.4 KiB
C
/*
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* QEMU I/O channels driver websockets
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef QIO_CHANNEL_WEBSOCK_H
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#define QIO_CHANNEL_WEBSOCK_H
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#include "io/channel.h"
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#include "qemu/buffer.h"
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#include "io/task.h"
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#define TYPE_QIO_CHANNEL_WEBSOCK "qio-channel-websock"
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#define QIO_CHANNEL_WEBSOCK(obj) \
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OBJECT_CHECK(QIOChannelWebsock, (obj), TYPE_QIO_CHANNEL_WEBSOCK)
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typedef struct QIOChannelWebsock QIOChannelWebsock;
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typedef union QIOChannelWebsockMask QIOChannelWebsockMask;
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union QIOChannelWebsockMask {
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char c[4];
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uint32_t u;
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};
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/**
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* QIOChannelWebsock
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*
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* The QIOChannelWebsock class provides a channel wrapper which
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* can transparently run the HTTP websockets protocol. This is
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* usually used over a TCP socket, but there is actually no
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* technical restriction on which type of master channel is
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* used as the transport.
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*
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* This channel object is currently only capable of running as
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* a websocket server and is a pretty crude implementation
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* of it, not supporting the full websockets protocol feature
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* set. It is sufficient to use with a simple websockets
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* client for encapsulating VNC for noVNC in-browser client.
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*/
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struct QIOChannelWebsock {
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QIOChannel parent;
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QIOChannel *master;
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Buffer encinput;
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Buffer encoutput;
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Buffer rawinput;
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Buffer rawoutput;
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size_t payload_remain;
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size_t pong_remain;
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QIOChannelWebsockMask mask;
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guint io_tag;
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Error *io_err;
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gboolean io_eof;
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uint8_t opcode;
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};
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/**
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* qio_channel_websock_new_server:
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* @master: the underlying channel object
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*
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* Create a new websockets channel that runs the server
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* side of the protocol.
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*
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* After creating the channel, it is mandatory to call
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* the qio_channel_websock_handshake() method before attempting
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* todo any I/O on the channel.
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*
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* Once the handshake has completed, all I/O should be done
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* via the new websocket channel object and not the original
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* master channel
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*
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* Returns: the new websockets channel object
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*/
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QIOChannelWebsock *
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qio_channel_websock_new_server(QIOChannel *master);
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/**
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* qio_channel_websock_handshake:
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* @ioc: the websocket channel object
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* @func: the callback to invoke when completed
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* @opaque: opaque data to pass to @func
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* @destroy: optional callback to free @opaque
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*
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* Perform the websocket handshake. This method
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* will return immediately and the handshake will
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* continue in the background, provided the main
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* loop is running. When the handshake is complete,
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* or fails, the @func callback will be invoked.
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*/
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void qio_channel_websock_handshake(QIOChannelWebsock *ioc,
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QIOTaskFunc func,
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gpointer opaque,
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GDestroyNotify destroy);
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#endif /* QIO_CHANNEL_WEBSOCK_H */
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