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 "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
  34 static QIODNSResolver *instance;
  35 static GOnce instance_init = G_ONCE_INIT;
  36
  37 static 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
  43 QIODNSResolver *qio_dns_resolver_get_instance(void)
  44 {
  45     g_once(&instance_init, qio_dns_resolve_init_instance, NULL);
  46     return instance;
  47 }
  48
  49 static 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
 134 static 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
 148 int 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
 177 struct QIODNSResolverLookupData {
 178     SocketAddress *addr;
 179     SocketAddress **addrs;
 180     size_t naddrs;
 181 };
 182
 183
 184 static 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
 199 static 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
 221 void 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
 243 void 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
 266 static const TypeInfo qio_dns_resolver_info = {
 267     .parent = TYPE_OBJECT,
 268     .name = TYPE_QIO_DNS_RESOLVER,
 269     .instance_size = sizeof(QIODNSResolver),
 270 };
 271
 272
 273 static void qio_dns_resolver_register_types(void)
 274 {
 275     type_register_static(&qio_dns_resolver_info);
 276 }
 277
 278
 279 type_init(qio_dns_resolver_register_types);