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 "qapi/qapi-visit-sockets.h"
  25#include "qemu/sockets.h"
  26#include "qapi/error.h"
  27#include "qemu/cutils.h"
  28#include "qemu/module.h"
  29
  30#ifndef AI_NUMERICSERV
  31# define AI_NUMERICSERV 0
  32#endif
  33
  34static QIODNSResolver *instance;
  35static GOnce instance_init = G_ONCE_INIT;
  36
  37static gpointer qio_dns_resolve_init_instance(gpointer unused G_GNUC_UNUSED)
  38{
  39    instance = QIO_DNS_RESOLVER(object_new(TYPE_QIO_DNS_RESOLVER));
  40    return NULL;
  41}
  42
  43QIODNSResolver *qio_dns_resolver_get_instance(void)
  44{
  45    g_once(&instance_init, qio_dns_resolve_init_instance, NULL);
  46    return instance;
  47}
  48
  49static int qio_dns_resolver_lookup_sync_inet(QIODNSResolver *resolver,
  50                                             SocketAddress *addr,
  51                                             size_t *naddrs,
  52                                             SocketAddress ***addrs,
  53                                             Error **errp)
  54{
  55    struct addrinfo ai, *res, *e;
  56    InetSocketAddress *iaddr = &addr->u.inet;
  57    char port[33];
  58    char uaddr[INET6_ADDRSTRLEN + 1];
  59    char uport[33];
  60    int rc;
  61    Error *err = NULL;
  62    size_t i;
  63
  64    *naddrs = 0;
  65    *addrs = NULL;
  66
  67    memset(&ai, 0, sizeof(ai));
  68    ai.ai_flags = AI_PASSIVE;
  69    if (iaddr->has_numeric && iaddr->numeric) {
  70        ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
  71    }
  72    ai.ai_family = inet_ai_family_from_address(iaddr, &err);
  73    ai.ai_socktype = SOCK_STREAM;
  74
  75    if (err) {
  76        error_propagate(errp, err);
  77        return -1;
  78    }
  79
  80    if (iaddr->host == NULL) {
  81        error_setg(errp, "host not specified");
  82        return -1;
  83    }
  84    if (iaddr->port != NULL) {
  85        pstrcpy(port, sizeof(port), iaddr->port);
  86    } else {
  87        port[0] = '\0';
  88    }
  89
  90    rc = getaddrinfo(strlen(iaddr->host) ? iaddr->host : NULL,
  91                     strlen(port) ? port : NULL, &ai, &res);
  92    if (rc != 0) {
  93        error_setg(errp, "address resolution failed for %s:%s: %s",
  94                   iaddr->host, port, gai_strerror(rc));
  95        return -1;
  96    }
  97
  98    for (e = res; e != NULL; e = e->ai_next) {
  99        (*naddrs)++;
 100    }
 101
 102    *addrs = g_new0(SocketAddress *, *naddrs);
 103
 104    /* create socket + bind */
 105    for (i = 0, e = res; e != NULL; i++, e = e->ai_next) {
 106        SocketAddress *newaddr = g_new0(SocketAddress, 1);
 107
 108        newaddr->type = SOCKET_ADDRESS_TYPE_INET;
 109
 110        getnameinfo((struct sockaddr *)e->ai_addr, e->ai_addrlen,
 111                    uaddr, INET6_ADDRSTRLEN, uport, 32,
 112                    NI_NUMERICHOST | NI_NUMERICSERV);
 113
 114        newaddr->u.inet = (InetSocketAddress){
 115            .host = g_strdup(uaddr),
 116            .port = g_strdup(uport),
 117            .has_numeric = true,
 118            .numeric = true,
 119            .has_to = iaddr->has_to,
 120            .to = iaddr->to,
 121            .has_ipv4 = iaddr->has_ipv4,
 122            .ipv4 = iaddr->ipv4,
 123            .has_ipv6 = iaddr->has_ipv6,
 124            .ipv6 = iaddr->ipv6,
 125        };
 126
 127        (*addrs)[i] = newaddr;
 128    }
 129    freeaddrinfo(res);
 130    return 0;
 131}
 132
 133
 134static int qio_dns_resolver_lookup_sync_nop(QIODNSResolver *resolver,
 135                                            SocketAddress *addr,
 136                                            size_t *naddrs,
 137                                            SocketAddress ***addrs,
 138                                            Error **errp)
 139{
 140    *naddrs = 1;
 141    *addrs = g_new0(SocketAddress *, 1);
 142    (*addrs)[0] = QAPI_CLONE(SocketAddress, addr);
 143
 144    return 0;
 145}
 146
 147
 148int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
 149                                 SocketAddress *addr,
 150                                 size_t *naddrs,
 151                                 SocketAddress ***addrs,
 152                                 Error **errp)
 153{
 154    switch (addr->type) {
 155    case SOCKET_ADDRESS_TYPE_INET:
 156        return qio_dns_resolver_lookup_sync_inet(resolver,
 157                                                 addr,
 158                                                 naddrs,
 159                                                 addrs,
 160                                                 errp);
 161
 162    case SOCKET_ADDRESS_TYPE_UNIX:
 163    case SOCKET_ADDRESS_TYPE_VSOCK:
 164    case SOCKET_ADDRESS_TYPE_FD:
 165        return qio_dns_resolver_lookup_sync_nop(resolver,
 166                                                addr,
 167                                                naddrs,
 168                                                addrs,
 169                                                errp);
 170
 171    default:
 172        abort();
 173    }
 174}
 175
 176
 177struct QIODNSResolverLookupData {
 178    SocketAddress *addr;
 179    SocketAddress **addrs;
 180    size_t naddrs;
 181};
 182
 183
 184static void qio_dns_resolver_lookup_data_free(gpointer opaque)
 185{
 186    struct QIODNSResolverLookupData *data = opaque;
 187    size_t i;
 188
 189    qapi_free_SocketAddress(data->addr);
 190    for (i = 0; i < data->naddrs; i++) {
 191        qapi_free_SocketAddress(data->addrs[i]);
 192    }
 193
 194    g_free(data->addrs);
 195    g_free(data);
 196}
 197
 198
 199static void qio_dns_resolver_lookup_worker(QIOTask *task,
 200                                           gpointer opaque)
 201{
 202    QIODNSResolver *resolver = QIO_DNS_RESOLVER(qio_task_get_source(task));
 203    struct QIODNSResolverLookupData *data = opaque;
 204    Error *err = NULL;
 205
 206    qio_dns_resolver_lookup_sync(resolver,
 207                                 data->addr,
 208                                 &data->naddrs,
 209                                 &data->addrs,
 210                                 &err);
 211    if (err) {
 212        qio_task_set_error(task, err);
 213    } else {
 214        qio_task_set_result_pointer(task, opaque, NULL);
 215    }
 216
 217    object_unref(OBJECT(resolver));
 218}
 219
 220
 221void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
 222                                   SocketAddress *addr,
 223                                   QIOTaskFunc func,
 224                                   gpointer opaque,
 225                                   GDestroyNotify notify)
 226{
 227    QIOTask *task;
 228    struct QIODNSResolverLookupData *data =
 229        g_new0(struct QIODNSResolverLookupData, 1);
 230
 231    data->addr = QAPI_CLONE(SocketAddress, addr);
 232
 233    task = qio_task_new(OBJECT(resolver), func, opaque, notify);
 234
 235    qio_task_run_in_thread(task,
 236                           qio_dns_resolver_lookup_worker,
 237                           data,
 238                           qio_dns_resolver_lookup_data_free,
 239                           NULL);
 240}
 241
 242
 243void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
 244                                    QIOTask *task,
 245                                    size_t *naddrs,
 246                                    SocketAddress ***addrs)
 247{
 248    struct QIODNSResolverLookupData *data =
 249        qio_task_get_result_pointer(task);
 250    size_t i;
 251
 252    *naddrs = 0;
 253    *addrs = NULL;
 254    if (!data) {
 255        return;
 256    }
 257
 258    *naddrs = data->naddrs;
 259    *addrs = g_new0(SocketAddress *, data->naddrs);
 260    for (i = 0; i < data->naddrs; i++) {
 261        (*addrs)[i] = QAPI_CLONE(SocketAddress, data->addrs[i]);
 262    }
 263}
 264
 265
 266static const TypeInfo qio_dns_resolver_info = {
 267    .parent = TYPE_OBJECT,
 268    .name = TYPE_QIO_DNS_RESOLVER,
 269    .instance_size = sizeof(QIODNSResolver),
 270    .class_size = sizeof(QIODNSResolverClass),
 271};
 272
 273
 274static void qio_dns_resolver_register_types(void)
 275{
 276    type_register_static(&qio_dns_resolver_info);
 277}
 278
 279
 280type_init(qio_dns_resolver_register_types);
 281