io/dns-resolver.c

   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
  32 static QIODNSResolver *instance;
  33 static GOnce instance_init = G_ONCE_INIT;
  34
  35 static 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
  41 QIODNSResolver *qio_dns_resolver_get_instance(void)
  42 {
  43     g_once(&instance_init, qio_dns_resolve_init_instance, NULL);
  44     return instance;
  45 }
  46
  47 static 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.data;
  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         InetSocketAddress *newiaddr = g_new0(InetSocketAddress, 1);
 106         newaddr->u.inet.data = newiaddr;
 107         newaddr->type = SOCKET_ADDRESS_KIND_INET;
 108
 109         getnameinfo((struct sockaddr *)e->ai_addr, e->ai_addrlen,
 110                     uaddr, INET6_ADDRSTRLEN, uport, 32,
 111                     NI_NUMERICHOST | NI_NUMERICSERV);
 112
 113         *newiaddr = (InetSocketAddress){
 114             .host = g_strdup(uaddr),
 115             .port = g_strdup(uport),
 116             .has_numeric = true,
 117             .numeric = true,
 118             .has_to = iaddr->has_to,
 119             .to = iaddr->to,
 120             .has_ipv4 = false,
 121             .has_ipv6 = false,
 122         };
 123
 124         (*addrs)[i] = newaddr;
 125     }
 126     freeaddrinfo(res);
 127     return 0;
 128 }
 129
 130
 131 static int qio_dns_resolver_lookup_sync_nop(QIODNSResolver *resolver,
 132                                             SocketAddress *addr,
 133                                             size_t *naddrs,
 134                                             SocketAddress ***addrs,
 135                                             Error **errp)
 136 {
 137     *naddrs = 1;
 138     *addrs = g_new0(SocketAddress *, 1);
 139     (*addrs)[0] = QAPI_CLONE(SocketAddress, addr);
 140
 141     return 0;
 142 }
 143
 144
 145 int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
 146                                  SocketAddress *addr,
 147                                  size_t *naddrs,
 148                                  SocketAddress ***addrs,
 149                                  Error **errp)
 150 {
 151     switch (addr->type) {
 152     case SOCKET_ADDRESS_KIND_INET:
 153         return qio_dns_resolver_lookup_sync_inet(resolver,
 154                                                  addr,
 155                                                  naddrs,
 156                                                  addrs,
 157                                                  errp);
 158
 159     case SOCKET_ADDRESS_KIND_UNIX:
 160     case SOCKET_ADDRESS_KIND_VSOCK:
 161         return qio_dns_resolver_lookup_sync_nop(resolver,
 162                                                 addr,
 163                                                 naddrs,
 164                                                 addrs,
 165                                                 errp);
 166
 167     default:
 168         error_setg(errp, "Unknown socket address kind");
 169         return -1;
 170     }
 171 }
 172
 173
 174 struct QIODNSResolverLookupData {
 175     SocketAddress *addr;
 176     SocketAddress **addrs;
 177     size_t naddrs;
 178 };
 179
 180
 181 static void qio_dns_resolver_lookup_data_free(gpointer opaque)
 182 {
 183     struct QIODNSResolverLookupData *data = opaque;
 184     size_t i;
 185
 186     qapi_free_SocketAddress(data->addr);
 187     for (i = 0; i < data->naddrs; i++) {
 188         qapi_free_SocketAddress(data->addrs[i]);
 189     }
 190
 191     g_free(data->addrs);
 192     g_free(data);
 193 }
 194
 195
 196 static void qio_dns_resolver_lookup_worker(QIOTask *task,
 197                                            gpointer opaque)
 198 {
 199     QIODNSResolver *resolver = QIO_DNS_RESOLVER(qio_task_get_source(task));
 200     struct QIODNSResolverLookupData *data = opaque;
 201     Error *err = NULL;
 202
 203     qio_dns_resolver_lookup_sync(resolver,
 204                                  data->addr,
 205                                  &data->naddrs,
 206                                  &data->addrs,
 207                                  &err);
 208     if (err) {
 209         qio_task_set_error(task, err);
 210     } else {
 211         qio_task_set_result_pointer(task, opaque, NULL);
 212     }
 213
 214     object_unref(OBJECT(resolver));
 215 }
 216
 217
 218 void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
 219                                    SocketAddress *addr,
 220                                    QIOTaskFunc func,
 221                                    gpointer opaque,
 222                                    GDestroyNotify notify)
 223 {
 224     QIOTask *task;
 225     struct QIODNSResolverLookupData *data =
 226         g_new0(struct QIODNSResolverLookupData, 1);
 227
 228     data->addr = QAPI_CLONE(SocketAddress, addr);
 229
 230     task = qio_task_new(OBJECT(resolver), func, opaque, notify);
 231
 232     qio_task_run_in_thread(task,
 233                            qio_dns_resolver_lookup_worker,
 234                            data,
 235                            qio_dns_resolver_lookup_data_free);
 236 }
 237
 238
 239 void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
 240                                     QIOTask *task,
 241                                     size_t *naddrs,
 242                                     SocketAddress ***addrs)
 243 {
 244     struct QIODNSResolverLookupData *data =
 245         qio_task_get_result_pointer(task);
 246     size_t i;
 247
 248     *naddrs = 0;
 249     *addrs = NULL;
 250     if (!data) {
 251         return;
 252     }
 253
 254     *naddrs = data->naddrs;
 255     *addrs = g_new0(SocketAddress *, data->naddrs);
 256     for (i = 0; i < data->naddrs; i++) {
 257         (*addrs)[i] = QAPI_CLONE(SocketAddress, data->addrs[i]);
 258     }
 259 }
 260
 261
 262 static const TypeInfo qio_dns_resolver_info = {
 263     .parent = TYPE_OBJECT,
 264     .name = TYPE_QIO_DNS_RESOLVER,
 265     .instance_size = sizeof(QIODNSResolver),
 266     .class_size = sizeof(QIODNSResolverClass),
 267 };
 268
 269
 270 static void qio_dns_resolver_register_types(void)
 271 {
 272     type_register_static(&qio_dns_resolver_info);
 273 }
 274
 275
 276 type_init(qio_dns_resolver_register_types);