2bc58ffc29
For CONFIG_LINUX, implement the new zero copy flag and the optional callback io_flush on QIOChannelSocket, but enables it only when MSG_ZEROCOPY feature is available in the host kernel, which is checked on qio_channel_socket_connect_sync() qio_channel_socket_flush() was implemented by counting how many times sendmsg(...,MSG_ZEROCOPY) was successfully called, and then reading the socket's error queue, in order to find how many of them finished sending. Flush will loop until those counters are the same, or until some error occurs. Notes on using writev() with QIO_CHANNEL_WRITE_FLAG_ZERO_COPY: 1: Buffer - As MSG_ZEROCOPY tells the kernel to use the same user buffer to avoid copying, some caution is necessary to avoid overwriting any buffer before it's sent. If something like this happen, a newer version of the buffer may be sent instead. - If this is a problem, it's recommended to call qio_channel_flush() before freeing or re-using the buffer. 2: Locked memory - When using MSG_ZERCOCOPY, the buffer memory will be locked after queued, and unlocked after it's sent. - Depending on the size of each buffer, and how often it's sent, it may require a larger amount of locked memory than usually available to non-root user. - If the required amount of locked memory is not available, writev_zero_copy will return an error, which can abort an operation like migration, - Because of this, when an user code wants to add zero copy as a feature, it requires a mechanism to disable it, so it can still be accessible to less privileged users. Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <20220513062836.965425-4-leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
266 lines
9.1 KiB
C
266 lines
9.1 KiB
C
/*
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* QEMU I/O channels sockets driver
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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 2.1 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_SOCKET_H
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#define QIO_CHANNEL_SOCKET_H
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#include "io/channel.h"
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#include "io/task.h"
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#include "qemu/sockets.h"
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#include "qom/object.h"
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#define TYPE_QIO_CHANNEL_SOCKET "qio-channel-socket"
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OBJECT_DECLARE_SIMPLE_TYPE(QIOChannelSocket, QIO_CHANNEL_SOCKET)
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/**
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* QIOChannelSocket:
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*
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* The QIOChannelSocket class provides a channel implementation
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* that can transport data over a UNIX socket or TCP socket.
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* Beyond the core channel API, it also provides functionality
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* for accepting client connections, tuning some socket
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* parameters and getting socket address strings.
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*/
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struct QIOChannelSocket {
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QIOChannel parent;
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int fd;
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struct sockaddr_storage localAddr;
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socklen_t localAddrLen;
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struct sockaddr_storage remoteAddr;
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socklen_t remoteAddrLen;
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ssize_t zero_copy_queued;
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ssize_t zero_copy_sent;
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};
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/**
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* qio_channel_socket_new:
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*
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* Create a channel for performing I/O on a socket
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* connection, that is initially closed. After
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* creating the socket, it must be setup as a client
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* connection or server.
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*
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* Returns: the socket channel object
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*/
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QIOChannelSocket *
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qio_channel_socket_new(void);
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/**
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* qio_channel_socket_new_fd:
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* @fd: the socket file descriptor
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* @errp: pointer to a NULL-initialized error object
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*
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* Create a channel for performing I/O on the socket
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* connection represented by the file descriptor @fd.
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*
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* Returns: the socket channel object, or NULL on error
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*/
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QIOChannelSocket *
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qio_channel_socket_new_fd(int fd,
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Error **errp);
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/**
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* qio_channel_socket_connect_sync:
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* @ioc: the socket channel object
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* @addr: the address to connect to
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* @errp: pointer to a NULL-initialized error object
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*
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* Attempt to connect to the address @addr. This method
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* will run in the foreground so the caller will not regain
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* execution control until the connection is established or
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* an error occurs.
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*/
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int qio_channel_socket_connect_sync(QIOChannelSocket *ioc,
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SocketAddress *addr,
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Error **errp);
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/**
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* qio_channel_socket_connect_async:
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* @ioc: the socket channel object
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* @addr: the address to connect to
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* @callback: the function to invoke on completion
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* @opaque: user data to pass to @callback
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* @destroy: the function to free @opaque
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* @context: the context to run the async task. If %NULL, the default
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* context will be used.
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*
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* Attempt to connect to the address @addr. This method
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* will run in the background so the caller will regain
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* execution control immediately. The function @callback
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* will be invoked on completion or failure. The @addr
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* parameter will be copied, so may be freed as soon
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* as this function returns without waiting for completion.
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*/
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void qio_channel_socket_connect_async(QIOChannelSocket *ioc,
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SocketAddress *addr,
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QIOTaskFunc callback,
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gpointer opaque,
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GDestroyNotify destroy,
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GMainContext *context);
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/**
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* qio_channel_socket_listen_sync:
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* @ioc: the socket channel object
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* @addr: the address to listen to
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* @num: the expected ammount of connections
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* @errp: pointer to a NULL-initialized error object
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*
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* Attempt to listen to the address @addr. This method
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* will run in the foreground so the caller will not regain
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* execution control until the connection is established or
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* an error occurs.
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*/
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int qio_channel_socket_listen_sync(QIOChannelSocket *ioc,
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SocketAddress *addr,
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int num,
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Error **errp);
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/**
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* qio_channel_socket_listen_async:
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* @ioc: the socket channel object
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* @addr: the address to listen to
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* @num: the expected ammount of connections
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* @callback: the function to invoke on completion
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* @opaque: user data to pass to @callback
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* @destroy: the function to free @opaque
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* @context: the context to run the async task. If %NULL, the default
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* context will be used.
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*
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* Attempt to listen to the address @addr. This method
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* will run in the background so the caller will regain
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* execution control immediately. The function @callback
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* will be invoked on completion or failure. The @addr
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* parameter will be copied, so may be freed as soon
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* as this function returns without waiting for completion.
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*/
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void qio_channel_socket_listen_async(QIOChannelSocket *ioc,
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SocketAddress *addr,
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int num,
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QIOTaskFunc callback,
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gpointer opaque,
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GDestroyNotify destroy,
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GMainContext *context);
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/**
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* qio_channel_socket_dgram_sync:
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* @ioc: the socket channel object
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* @localAddr: the address to local bind address
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* @remoteAddr: the address to remote peer address
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* @errp: pointer to a NULL-initialized error object
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*
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* Attempt to initialize a datagram socket bound to
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* @localAddr and communicating with peer @remoteAddr.
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* This method will run in the foreground so the caller
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* will not regain execution control until the socket
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* is established or an error occurs.
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*/
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int qio_channel_socket_dgram_sync(QIOChannelSocket *ioc,
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SocketAddress *localAddr,
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SocketAddress *remoteAddr,
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Error **errp);
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/**
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* qio_channel_socket_dgram_async:
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* @ioc: the socket channel object
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* @localAddr: the address to local bind address
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* @remoteAddr: the address to remote peer address
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* @callback: the function to invoke on completion
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* @opaque: user data to pass to @callback
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* @destroy: the function to free @opaque
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* @context: the context to run the async task. If %NULL, the default
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* context will be used.
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*
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* Attempt to initialize a datagram socket bound to
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* @localAddr and communicating with peer @remoteAddr.
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* This method will run in the background so the caller
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* will regain execution control immediately. The function
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* @callback will be invoked on completion or failure.
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* The @localAddr and @remoteAddr parameters will be copied,
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* so may be freed as soon as this function returns without
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* waiting for completion.
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*/
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void qio_channel_socket_dgram_async(QIOChannelSocket *ioc,
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SocketAddress *localAddr,
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SocketAddress *remoteAddr,
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QIOTaskFunc callback,
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gpointer opaque,
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GDestroyNotify destroy,
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GMainContext *context);
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/**
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* qio_channel_socket_get_local_address:
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* @ioc: the socket channel object
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* @errp: pointer to a NULL-initialized error object
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*
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* Get the string representation of the local socket
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* address. A pointer to the allocated address information
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* struct will be returned, which the caller is required to
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* release with a call qapi_free_SocketAddress() when no
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* longer required.
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*
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* Returns: 0 on success, -1 on error
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*/
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SocketAddress *
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qio_channel_socket_get_local_address(QIOChannelSocket *ioc,
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Error **errp);
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/**
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* qio_channel_socket_get_remote_address:
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* @ioc: the socket channel object
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* @errp: pointer to a NULL-initialized error object
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*
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* Get the string representation of the local socket
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* address. A pointer to the allocated address information
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* struct will be returned, which the caller is required to
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* release with a call qapi_free_SocketAddress() when no
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* longer required.
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*
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* Returns: the socket address struct, or NULL on error
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*/
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SocketAddress *
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qio_channel_socket_get_remote_address(QIOChannelSocket *ioc,
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Error **errp);
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/**
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* qio_channel_socket_accept:
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* @ioc: the socket channel object
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* @errp: pointer to a NULL-initialized error object
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*
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* If the socket represents a server, then this accepts
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* a new client connection. The returned channel will
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* represent the connected client socket.
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*
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* Returns: the new client channel, or NULL on error
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*/
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QIOChannelSocket *
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qio_channel_socket_accept(QIOChannelSocket *ioc,
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Error **errp);
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#endif /* QIO_CHANNEL_SOCKET_H */
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