qemu/io/dns-resolver.c
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   1/*
   2 * QEMU DNS resolver
   3 *
   4 * Copyright (c) 2016 Red Hat, Inc.
   5 *
   6 * This library is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU Lesser General Public
   8 * License as published by the Free Software Foundation; either
   9 * version 2 of the License, or (at your option) any later version.
  10 *
  11 * This library is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 * Lesser General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU Lesser General Public
  17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18 *
  19 */
  20
  21#include "qemu/osdep.h"
  22#include "io/dns-resolver.h"
  23#include "qapi/clone-visitor.h"
  24#include "qemu/sockets.h"
  25#include "qapi/error.h"
  26#include "qemu/cutils.h"
  27
  28#ifndef AI_NUMERICSERV
  29# define AI_NUMERICSERV 0
  30#endif
  31
  32static QIODNSResolver *instance;
  33static GOnce instance_init = G_ONCE_INIT;
  34
  35static gpointer qio_dns_resolve_init_instance(gpointer unused G_GNUC_UNUSED)
  36{
  37    instance = QIO_DNS_RESOLVER(object_new(TYPE_QIO_DNS_RESOLVER));
  38    return NULL;
  39}
  40
  41QIODNSResolver *qio_dns_resolver_get_instance(void)
  42{
  43    g_once(&instance_init, qio_dns_resolve_init_instance, NULL);
  44    return instance;
  45}
  46
  47static int qio_dns_resolver_lookup_sync_inet(QIODNSResolver *resolver,
  48                                             SocketAddress *addr,
  49                                             size_t *naddrs,
  50                                             SocketAddress ***addrs,
  51                                             Error **errp)
  52{
  53    struct addrinfo ai, *res, *e;
  54    InetSocketAddress *iaddr = &addr->u.inet;
  55    char port[33];
  56    char uaddr[INET6_ADDRSTRLEN + 1];
  57    char uport[33];
  58    int rc;
  59    Error *err = NULL;
  60    size_t i;
  61
  62    *naddrs = 0;
  63    *addrs = NULL;
  64
  65    memset(&ai, 0, sizeof(ai));
  66    ai.ai_flags = AI_PASSIVE;
  67    if (iaddr->has_numeric && iaddr->numeric) {
  68        ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
  69    }
  70    ai.ai_family = inet_ai_family_from_address(iaddr, &err);
  71    ai.ai_socktype = SOCK_STREAM;
  72
  73    if (err) {
  74        error_propagate(errp, err);
  75        return -1;
  76    }
  77
  78    if (iaddr->host == NULL) {
  79        error_setg(errp, "host not specified");
  80        return -1;
  81    }
  82    if (iaddr->port != NULL) {
  83        pstrcpy(port, sizeof(port), iaddr->port);
  84    } else {
  85        port[0] = '\0';
  86    }
  87
  88    rc = getaddrinfo(strlen(iaddr->host) ? iaddr->host : NULL,
  89                     strlen(port) ? port : NULL, &ai, &res);
  90    if (rc != 0) {
  91        error_setg(errp, "address resolution failed for %s:%s: %s",
  92                   iaddr->host, port, gai_strerror(rc));
  93        return -1;
  94    }
  95
  96    for (e = res; e != NULL; e = e->ai_next) {
  97        (*naddrs)++;
  98    }
  99
 100    *addrs = g_new0(SocketAddress *, *naddrs);
 101
 102    /* create socket + bind */
 103    for (i = 0, e = res; e != NULL; i++, e = e->ai_next) {
 104        SocketAddress *newaddr = g_new0(SocketAddress, 1);
 105
 106        newaddr->type = SOCKET_ADDRESS_TYPE_INET;
 107
 108        getnameinfo((struct sockaddr *)e->ai_addr, e->ai_addrlen,
 109                    uaddr, INET6_ADDRSTRLEN, uport, 32,
 110                    NI_NUMERICHOST | NI_NUMERICSERV);
 111
 112        newaddr->u.inet = (InetSocketAddress){
 113            .host = g_strdup(uaddr),
 114            .port = g_strdup(uport),
 115            .has_numeric = true,
 116            .numeric = true,
 117            .has_to = iaddr->has_to,
 118            .to = iaddr->to,
 119            .has_ipv4 = iaddr->has_ipv4,
 120            .ipv4 = iaddr->ipv4,
 121            .has_ipv6 = iaddr->has_ipv6,
 122            .ipv6 = iaddr->ipv6,
 123        };
 124
 125        (*addrs)[i] = newaddr;
 126    }
 127    freeaddrinfo(res);
 128    return 0;
 129}
 130
 131
 132static int qio_dns_resolver_lookup_sync_nop(QIODNSResolver *resolver,
 133                                            SocketAddress *addr,
 134                                            size_t *naddrs,
 135                                            SocketAddress ***addrs,
 136                                            Error **errp)
 137{
 138    *naddrs = 1;
 139    *addrs = g_new0(SocketAddress *, 1);
 140    (*addrs)[0] = QAPI_CLONE(SocketAddress, addr);
 141
 142    return 0;
 143}
 144
 145
 146int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
 147                                 SocketAddress *addr,
 148                                 size_t *naddrs,
 149                                 SocketAddress ***addrs,
 150                                 Error **errp)
 151{
 152    switch (addr->type) {
 153    case SOCKET_ADDRESS_TYPE_INET:
 154        return qio_dns_resolver_lookup_sync_inet(resolver,
 155                                                 addr,
 156                                                 naddrs,
 157                                                 addrs,
 158                                                 errp);
 159
 160    case SOCKET_ADDRESS_TYPE_UNIX:
 161    case SOCKET_ADDRESS_TYPE_VSOCK:
 162    case SOCKET_ADDRESS_TYPE_FD:
 163        return qio_dns_resolver_lookup_sync_nop(resolver,
 164                                                addr,
 165                                                naddrs,
 166                                                addrs,
 167                                                errp);
 168
 169    default:
 170        abort();
 171    }
 172}
 173
 174
 175struct QIODNSResolverLookupData {
 176    SocketAddress *addr;
 177    SocketAddress **addrs;
 178    size_t naddrs;
 179};
 180
 181
 182static void qio_dns_resolver_lookup_data_free(gpointer opaque)
 183{
 184    struct QIODNSResolverLookupData *data = opaque;
 185    size_t i;
 186
 187    qapi_free_SocketAddress(data->addr);
 188    for (i = 0; i < data->naddrs; i++) {
 189        qapi_free_SocketAddress(data->addrs[i]);
 190    }
 191
 192    g_free(data->addrs);
 193    g_free(data);
 194}
 195
 196
 197static void qio_dns_resolver_lookup_worker(QIOTask *task,
 198                                           gpointer opaque)
 199{
 200    QIODNSResolver *resolver = QIO_DNS_RESOLVER(qio_task_get_source(task));
 201    struct QIODNSResolverLookupData *data = opaque;
 202    Error *err = NULL;
 203
 204    qio_dns_resolver_lookup_sync(resolver,
 205                                 data->addr,
 206                                 &data->naddrs,
 207                                 &data->addrs,
 208                                 &err);
 209    if (err) {
 210        qio_task_set_error(task, err);
 211    } else {
 212        qio_task_set_result_pointer(task, opaque, NULL);
 213    }
 214
 215    object_unref(OBJECT(resolver));
 216}
 217
 218
 219void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
 220                                   SocketAddress *addr,
 221                                   QIOTaskFunc func,
 222                                   gpointer opaque,
 223                                   GDestroyNotify notify)
 224{
 225    QIOTask *task;
 226    struct QIODNSResolverLookupData *data =
 227        g_new0(struct QIODNSResolverLookupData, 1);
 228
 229    data->addr = QAPI_CLONE(SocketAddress, addr);
 230
 231    task = qio_task_new(OBJECT(resolver), func, opaque, notify);
 232
 233    qio_task_run_in_thread(task,
 234                           qio_dns_resolver_lookup_worker,
 235                           data,
 236                           qio_dns_resolver_lookup_data_free);
 237}
 238
 239
 240void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
 241                                    QIOTask *task,
 242                                    size_t *naddrs,
 243                                    SocketAddress ***addrs)
 244{
 245    struct QIODNSResolverLookupData *data =
 246        qio_task_get_result_pointer(task);
 247    size_t i;
 248
 249    *naddrs = 0;
 250    *addrs = NULL;
 251    if (!data) {
 252        return;
 253    }
 254
 255    *naddrs = data->naddrs;
 256    *addrs = g_new0(SocketAddress *, data->naddrs);
 257    for (i = 0; i < data->naddrs; i++) {
 258        (*addrs)[i] = QAPI_CLONE(SocketAddress, data->addrs[i]);
 259    }
 260}
 261
 262
 263static const TypeInfo qio_dns_resolver_info = {
 264    .parent = TYPE_OBJECT,
 265    .name = TYPE_QIO_DNS_RESOLVER,
 266    .instance_size = sizeof(QIODNSResolver),
 267    .class_size = sizeof(QIODNSResolverClass),
 268};
 269
 270
 271static void qio_dns_resolver_register_types(void)
 272{
 273    type_register_static(&qio_dns_resolver_info);
 274}
 275
 276
 277type_init(qio_dns_resolver_register_types);
 278