bd269ebc82
SocketAddressLegacy is a simple union, and simple unions are awkward: they have their variant members wrapped in a "data" object on the wire, and require additional indirections in C. SocketAddress is the equivalent flat union. Convert all users of SocketAddressLegacy to SocketAddress, except for existing external interfaces. See also commit fce5d53..9445673 and 85a82e8..c5f1ae3. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1493192202-3184-7-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> [Minor editing accident fixed, commit message and a comment tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com>
229 lines
7.5 KiB
C
229 lines
7.5 KiB
C
/*
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* QEMU DNS resolver
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*
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* Copyright (c) 2016-2017 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_DNS_RESOLVER_H
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#define QIO_DNS_RESOLVER_H
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#include "qemu-common.h"
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#include "qom/object.h"
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#include "io/task.h"
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#define TYPE_QIO_DNS_RESOLVER "qio-dns-resolver"
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#define QIO_DNS_RESOLVER(obj) \
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OBJECT_CHECK(QIODNSResolver, (obj), TYPE_QIO_DNS_RESOLVER)
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#define QIO_DNS_RESOLVER_CLASS(klass) \
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OBJECT_CLASS_CHECK(QIODNSResolverClass, klass, TYPE_QIO_DNS_RESOLVER)
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#define QIO_DNS_RESOLVER_GET_CLASS(obj) \
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OBJECT_GET_CLASS(QIODNSResolverClass, obj, TYPE_QIO_DNS_RESOLVER)
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typedef struct QIODNSResolver QIODNSResolver;
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typedef struct QIODNSResolverClass QIODNSResolverClass;
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/**
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* QIODNSResolver:
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*
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* The QIODNSResolver class provides a framework for doing
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* DNS resolution on SocketAddress objects, independently
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* of socket creation.
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*
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* <example>
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* <title>Resolving addresses synchronously</title>
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* <programlisting>
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* int mylisten(SocketAddress *addr, Error **errp) {
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* QIODNSResolver *resolver = qio_dns_resolver_get_instance();
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* SocketAddress **rawaddrs = NULL;
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* size_t nrawaddrs = 0;
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* Error *err = NULL;
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* QIOChannel **socks = NULL;
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* size_t nsocks = 0;
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*
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* if (qio_dns_resolver_lookup_sync(dns, addr, &nrawaddrs,
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* &rawaddrs, errp) < 0) {
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* return -1;
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* }
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*
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* for (i = 0; i < nrawaddrs; i++) {
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* QIOChannel *sock = qio_channel_new();
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* Error *local_err = NULL;
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* qio_channel_listen_sync(sock, rawaddrs[i], &local_err);
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* if (local_err) {
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* error_propagate(&err, local_err);
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* } else {
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* socks = g_renew(QIOChannelSocket *, socks, nsocks + 1);
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* socks[nsocks++] = sock;
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* }
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* qapi_free_SocketAddress(rawaddrs[i]);
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* }
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* g_free(rawaddrs);
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*
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* if (nsocks == 0) {
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* error_propagate(errp, err);
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* } else {
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* error_free(err);
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* }
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* }
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* </programlisting>
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* </example>
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*
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* <example>
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* <title>Resolving addresses asynchronously</title>
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* <programlisting>
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* typedef struct MyListenData {
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* Error *err;
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* QIOChannelSocket **socks;
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* size_t nsocks;
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* } MyListenData;
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*
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* void mylistenresult(QIOTask *task, void *opaque) {
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* MyListenData *data = opaque;
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* QIODNSResolver *resolver =
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* QIO_DNS_RESOLVER(qio_task_get_source(task);
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* SocketAddress **rawaddrs = NULL;
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* size_t nrawaddrs = 0;
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* Error *err = NULL;
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*
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* if (qio_task_propagate_error(task, &data->err)) {
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* return;
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* }
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*
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* qio_dns_resolver_lookup_result(resolver, task,
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* &nrawaddrs, &rawaddrs);
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*
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* for (i = 0; i < nrawaddrs; i++) {
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* QIOChannel *sock = qio_channel_new();
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* Error *local_err = NULL;
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* qio_channel_listen_sync(sock, rawaddrs[i], &local_err);
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* if (local_err) {
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* error_propagate(&err, local_err);
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* } else {
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* socks = g_renew(QIOChannelSocket *, socks, nsocks + 1);
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* socks[nsocks++] = sock;
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* }
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* qapi_free_SocketAddress(rawaddrs[i]);
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* }
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* g_free(rawaddrs);
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*
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* if (nsocks == 0) {
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* error_propagate(&data->err, err);
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* } else {
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* error_free(err);
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* }
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* }
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*
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* void mylisten(SocketAddress *addr, MyListenData *data) {
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* QIODNSResolver *resolver = qio_dns_resolver_get_instance();
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* qio_dns_resolver_lookup_async(dns, addr,
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* mylistenresult, data, NULL);
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* }
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* </programlisting>
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* </example>
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*/
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struct QIODNSResolver {
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Object parent;
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};
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struct QIODNSResolverClass {
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ObjectClass parent;
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};
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/**
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* qio_dns_resolver_get_instance:
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*
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* Get the singleton dns resolver instance. The caller
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* does not own a reference on the returned object.
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*
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* Returns: the single dns resolver instance
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*/
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QIODNSResolver *qio_dns_resolver_get_instance(void);
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/**
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* qio_dns_resolver_lookup_sync:
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* @resolver: the DNS resolver instance
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* @addr: the address to resolve
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* @naddr: pointer to hold number of resolved addresses
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* @addrs: pointer to hold resolved addresses
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* @errp: pointer to NULL initialized error object
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*
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* This will attempt to resolve the address provided
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* in @addr. If resolution succeeds, @addrs will be filled
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* with all the resolved addresses. @naddrs will specify
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* the number of entries allocated in @addrs. The caller
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* is responsible for freeing each entry in @addrs, as
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* well as @addrs itself. @naddrs is guaranteed to be
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* greater than zero on success.
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*
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* DNS resolution will be done synchronously so execution
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* of the caller may be blocked for an arbitrary length
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* of time.
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*
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* Returns: 0 if resolution was successful, -1 on error
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*/
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int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
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SocketAddress *addr,
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size_t *naddrs,
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SocketAddress ***addrs,
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Error **errp);
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/**
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* qio_dns_resolver_lookup_async:
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* @resolver: the DNS resolver instance
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* @addr: the address to resolve
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* @func: the callback to invoke on lookup completion
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* @opaque: data blob to pass to @func
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* @notify: the callback to free @opaque, or NULL
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*
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* This will attempt to resolve the address provided
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* in @addr. The callback @func will be invoked when
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* resolution has either completed or failed. On
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* success, the @func should call the method
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* qio_dns_resolver_lookup_result() to obtain the
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* results.
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*
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* DNS resolution will be done asynchronously so execution
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* of the caller will not be blocked.
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*/
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void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
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SocketAddress *addr,
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QIOTaskFunc func,
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gpointer opaque,
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GDestroyNotify notify);
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/**
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* qio_dns_resolver_lookup_result:
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* @resolver: the DNS resolver instance
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* @task: the task object to get results for
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* @naddr: pointer to hold number of resolved addresses
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* @addrs: pointer to hold resolved addresses
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*
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* This method should be called from the callback passed
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* to qio_dns_resolver_lookup_async() in order to obtain
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* results. @addrs will be filled with all the resolved
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* addresses. @naddrs will specify the number of entries
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* allocated in @addrs. The caller is responsible for
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* freeing each entry in @addrs, as well as @addrs itself.
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*/
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void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
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QIOTask *task,
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size_t *naddrs,
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SocketAddress ***addrs);
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#endif /* QIO_DNS_RESOLVER_H */
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