io: add QIOChannelWebsock class

Add a QIOChannel subclass that can run the websocket protocol over
the top of another QIOChannel instance. This initial implementation
is only capable of acting as a websockets server. There is no support
for acting as a websockets client yet.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

include/io/channel-websock.h

@@ -0,0 +1,108 @@
+/*
+ * QEMU I/O channels driver websockets
+ *
+ * Copyright (c) 2015 Red Hat, Inc.
+ *
+ * This library 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 2 of the License, or (at your option) any later version.
+ *
+ * This library 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 library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QIO_CHANNEL_WEBSOCK_H__
+#define QIO_CHANNEL_WEBSOCK_H__
+
+#include "io/channel.h"
+#include "qemu/buffer.h"
+#include "io/task.h"
+
+#define TYPE_QIO_CHANNEL_WEBSOCK "qio-channel-websock"
+#define QIO_CHANNEL_WEBSOCK(obj)                                     \
+    OBJECT_CHECK(QIOChannelWebsock, (obj), TYPE_QIO_CHANNEL_WEBSOCK)
+
+typedef struct QIOChannelWebsock QIOChannelWebsock;
+typedef union QIOChannelWebsockMask QIOChannelWebsockMask;
+
+union QIOChannelWebsockMask {
+    char c[4];
+    uint32_t u;
+};
+
+/**
+ * QIOChannelWebsock
+ *
+ * The QIOChannelWebsock class provides a channel wrapper which
+ * can transparently run the HTTP websockets protocol. This is
+ * usually used over a TCP socket, but there is actually no
+ * technical restriction on which type of master channel is
+ * used as the transport.
+ *
+ * This channel object is currently only capable of running as
+ * a websocket server and is a pretty crude implementation
+ * of it, not supporting the full websockets protocol feature
+ * set. It is sufficient to use with a simple websockets
+ * client for encapsulating VNC for noVNC in-browser client.
+ */
+
+struct QIOChannelWebsock {
+    QIOChannel parent;
+    QIOChannel *master;
+    Buffer encinput;
+    Buffer encoutput;
+    Buffer rawinput;
+    Buffer rawoutput;
+    size_t payload_remain;
+    QIOChannelWebsockMask mask;
+    guint io_tag;
+    Error *io_err;
+    gboolean io_eof;
+};
+
+/**
+ * qio_channel_websock_new_server:
+ * @master: the underlying channel object
+ *
+ * Create a new websockets channel that runs the server
+ * side of the protocol.
+ *
+ * After creating the channel, it is mandatory to call
+ * the qio_channel_websock_handshake() method before attempting
+ * todo any I/O on the channel.
+ *
+ * Once the handshake has completed, all I/O should be done
+ * via the new websocket channel object and not the original
+ * master channel
+ *
+ * Returns: the new websockets channel object
+ */
+QIOChannelWebsock *
+qio_channel_websock_new_server(QIOChannel *master);
+
+/**
+ * qio_channel_websock_handshake:
+ * @ioc: the websocket channel object
+ * @func: the callback to invoke when completed
+ * @opaque: opaque data to pass to @func
+ * @destroy: optional callback to free @opaque
+ *
+ * Perform the websocket handshake. This method
+ * will return immediately and the handshake will
+ * continue in the background, provided the main
+ * loop is running. When the handshake is complete,
+ * or fails, the @func callback will be invoked.
+ */
+void qio_channel_websock_handshake(QIOChannelWebsock *ioc,
+                                   QIOTaskFunc func,
+                                   gpointer opaque,
+                                   GDestroyNotify destroy);
+
+#endif /* QIO_CHANNEL_WEBSOCK_H__ */