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 2.1 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#ifdef HAVE_IPPROTO_MPTCP
 126            .has_mptcp = iaddr->has_mptcp,
 127            .mptcp = iaddr->mptcp,
 128#endif
 129        };
 130
 131        (*addrs)[i] = newaddr;
 132    }
 133    freeaddrinfo(res);
 134    return 0;
 135}
 136
 137
 138static int qio_dns_resolver_lookup_sync_nop(QIODNSResolver *resolver,
 139                                            SocketAddress *addr,
 140                                            size_t *naddrs,
 141                                            SocketAddress ***addrs,
 142                                            Error **errp)
 143{
 144    *naddrs = 1;
 145    *addrs = g_new0(SocketAddress *, 1);
 146    (*addrs)[0] = QAPI_CLONE(SocketAddress, addr);
 147
 148    return 0;
 149}
 150
 151
 152int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
 153                                 SocketAddress *addr,
 154                                 size_t *naddrs,
 155                                 SocketAddress ***addrs,
 156                                 Error **errp)
 157{
 158    switch (addr->type) {
 159    case SOCKET_ADDRESS_TYPE_INET:
 160        return qio_dns_resolver_lookup_sync_inet(resolver,
 161                                                 addr,
 162                                                 naddrs,
 163                                                 addrs,
 164                                                 errp);
 165
 166    case SOCKET_ADDRESS_TYPE_UNIX:
 167    case SOCKET_ADDRESS_TYPE_VSOCK:
 168    case SOCKET_ADDRESS_TYPE_FD:
 169        return qio_dns_resolver_lookup_sync_nop(resolver,
 170                                                addr,
 171                                                naddrs,
 172                                                addrs,
 173                                                errp);
 174
 175    default:
 176        abort();
 177    }
 178}
 179
 180
 181struct QIODNSResolverLookupData {
 182    SocketAddress *addr;
 183    SocketAddress **addrs;
 184    size_t naddrs;
 185};
 186
 187
 188static void qio_dns_resolver_lookup_data_free(gpointer opaque)
 189{
 190    struct QIODNSResolverLookupData *data = opaque;
 191    size_t i;
 192
 193    qapi_free_SocketAddress(data->addr);
 194    for (i = 0; i < data->naddrs; i++) {
 195        qapi_free_SocketAddress(data->addrs[i]);
 196    }
 197
 198    g_free(data->addrs);
 199    g_free(data);
 200}
 201
 202
 203static void qio_dns_resolver_lookup_worker(QIOTask *task,
 204                                           gpointer opaque)
 205{
 206    QIODNSResolver *resolver = QIO_DNS_RESOLVER(qio_task_get_source(task));
 207    struct QIODNSResolverLookupData *data = opaque;
 208    Error *err = NULL;
 209
 210    qio_dns_resolver_lookup_sync(resolver,
 211                                 data->addr,
 212                                 &data->naddrs,
 213                                 &data->addrs,
 214                                 &err);
 215    if (err) {
 216        qio_task_set_error(task, err);
 217    } else {
 218        qio_task_set_result_pointer(task, opaque, NULL);
 219    }
 220
 221    object_unref(OBJECT(resolver));
 222}
 223
 224
 225void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
 226                                   SocketAddress *addr,
 227                                   QIOTaskFunc func,
 228                                   gpointer opaque,
 229                                   GDestroyNotify notify)
 230{
 231    QIOTask *task;
 232    struct QIODNSResolverLookupData *data =
 233        g_new0(struct QIODNSResolverLookupData, 1);
 234
 235    data->addr = QAPI_CLONE(SocketAddress, addr);
 236
 237    task = qio_task_new(OBJECT(resolver), func, opaque, notify);
 238
 239    qio_task_run_in_thread(task,
 240                           qio_dns_resolver_lookup_worker,
 241                           data,
 242                           qio_dns_resolver_lookup_data_free,
 243                           NULL);
 244}
 245
 246
 247void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
 248                                    QIOTask *task,
 249                                    size_t *naddrs,
 250                                    SocketAddress ***addrs)
 251{
 252    struct QIODNSResolverLookupData *data =
 253        qio_task_get_result_pointer(task);
 254    size_t i;
 255
 256    *naddrs = 0;
 257    *addrs = NULL;
 258    if (!data) {
 259        return;
 260    }
 261
 262    *naddrs = data->naddrs;
 263    *addrs = g_new0(SocketAddress *, data->naddrs);
 264    for (i = 0; i < data->naddrs; i++) {
 265        (*addrs)[i] = QAPI_CLONE(SocketAddress, data->addrs[i]);
 266    }
 267}
 268
 269
 270static const TypeInfo qio_dns_resolver_info = {
 271    .parent = TYPE_OBJECT,
 272    .name = TYPE_QIO_DNS_RESOLVER,
 273    .instance_size = sizeof(QIODNSResolver),
 274};
 275
 276
 277static void qio_dns_resolver_register_types(void)
 278{
 279    type_register_static(&qio_dns_resolver_info);
 280}
 281
 282
 283type_init(qio_dns_resolver_register_types);
 284