block/nbd.c

   1 /*
   2  * QEMU Block driver for  NBD
   3  *
   4  * Copyright (C) 2008 Bull S.A.S.
   5  *     Author: Laurent Vivier <[email protected]>
   6  *
   7  * Some parts:
   8  *    Copyright (C) 2007 Anthony Liguori <[email protected]>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26  * THE SOFTWARE.
  27  */
  28
  29 #include "qemu/osdep.h"
  30 #include "block/nbd-client.h"
  31 #include "qapi/error.h"
  32 #include "qemu/uri.h"
  33 #include "block/block_int.h"
  34 #include "qemu/module.h"
  35 #include "qapi/qmp/qdict.h"
  36 #include "qapi/qmp/qjson.h"
  37 #include "qapi/qmp/qint.h"
  38 #include "qapi/qmp/qstring.h"
  39 #include "qemu/cutils.h"
  40
  41 #define EN_OPTSTR ":exportname="
  42
  43 typedef struct BDRVNBDState {
  44     NbdClientSession client;
  45
  46     /* For nbd_refresh_filename() */
  47     char *path, *host, *port, *export, *tlscredsid;
  48 } BDRVNBDState;
  49
  50 static int nbd_parse_uri(const char *filename, QDict *options)
  51 {
  52     URI *uri;
  53     const char *p;
  54     QueryParams *qp = NULL;
  55     int ret = 0;
  56     bool is_unix;
  57
  58     uri = uri_parse(filename);
  59     if (!uri) {
  60         return -EINVAL;
  61     }
  62
  63     /* transport */
  64     if (!strcmp(uri->scheme, "nbd")) {
  65         is_unix = false;
  66     } else if (!strcmp(uri->scheme, "nbd+tcp")) {
  67         is_unix = false;
  68     } else if (!strcmp(uri->scheme, "nbd+unix")) {
  69         is_unix = true;
  70     } else {
  71         ret = -EINVAL;
  72         goto out;
  73     }
  74
  75     p = uri->path ? uri->path : "/";
  76     p += strspn(p, "/");
  77     if (p[0]) {
  78         qdict_put(options, "export", qstring_from_str(p));
  79     }
  80
  81     qp = query_params_parse(uri->query);
  82     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  83         ret = -EINVAL;
  84         goto out;
  85     }
  86
  87     if (is_unix) {
  88         /* nbd+unix:///export?socket=path */
  89         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  90             ret = -EINVAL;
  91             goto out;
  92         }
  93         qdict_put(options, "path", qstring_from_str(qp->p[0].value));
  94     } else {
  95         QString *host;
  96         /* nbd[+tcp]://host[:port]/export */
  97         if (!uri->server) {
  98             ret = -EINVAL;
  99             goto out;
 100         }
 101
 102         /* strip braces from literal IPv6 address */
 103         if (uri->server[0] == '[') {
 104             host = qstring_from_substr(uri->server, 1,
 105                                        strlen(uri->server) - 2);
 106         } else {
 107             host = qstring_from_str(uri->server);
 108         }
 109
 110         qdict_put(options, "host", host);
 111         if (uri->port) {
 112             char* port_str = g_strdup_printf("%d", uri->port);
 113             qdict_put(options, "port", qstring_from_str(port_str));
 114             g_free(port_str);
 115         }
 116     }
 117
 118 out:
 119     if (qp) {
 120         query_params_free(qp);
 121     }
 122     uri_free(uri);
 123     return ret;
 124 }
 125
 126 static void nbd_parse_filename(const char *filename, QDict *options,
 127                                Error **errp)
 128 {
 129     char *file;
 130     char *export_name;
 131     const char *host_spec;
 132     const char *unixpath;
 133
 134     if (qdict_haskey(options, "host")
 135         || qdict_haskey(options, "port")
 136         || qdict_haskey(options, "path"))
 137     {
 138         error_setg(errp, "host/port/path and a file name may not be specified "
 139                          "at the same time");
 140         return;
 141     }
 142
 143     if (strstr(filename, "://")) {
 144         int ret = nbd_parse_uri(filename, options);
 145         if (ret < 0) {
 146             error_setg(errp, "No valid URL specified");
 147         }
 148         return;
 149     }
 150
 151     file = g_strdup(filename);
 152
 153     export_name = strstr(file, EN_OPTSTR);
 154     if (export_name) {
 155         if (export_name[strlen(EN_OPTSTR)] == 0) {
 156             goto out;
 157         }
 158         export_name[0] = 0; /* truncate 'file' */
 159         export_name += strlen(EN_OPTSTR);
 160
 161         qdict_put(options, "export", qstring_from_str(export_name));
 162     }
 163
 164     /* extract the host_spec - fail if it's not nbd:... */
 165     if (!strstart(file, "nbd:", &host_spec)) {
 166         error_setg(errp, "File name string for NBD must start with 'nbd:'");
 167         goto out;
 168     }
 169
 170     if (!*host_spec) {
 171         goto out;
 172     }
 173
 174     /* are we a UNIX or TCP socket? */
 175     if (strstart(host_spec, "unix:", &unixpath)) {
 176         qdict_put(options, "path", qstring_from_str(unixpath));
 177     } else {
 178         InetSocketAddress *addr = NULL;
 179
 180         addr = inet_parse(host_spec, errp);
 181         if (!addr) {
 182             goto out;
 183         }
 184
 185         qdict_put(options, "host", qstring_from_str(addr->host));
 186         qdict_put(options, "port", qstring_from_str(addr->port));
 187         qapi_free_InetSocketAddress(addr);
 188     }
 189
 190 out:
 191     g_free(file);
 192 }
 193
 194 static SocketAddress *nbd_config(BDRVNBDState *s, QemuOpts *opts, Error **errp)
 195 {
 196     SocketAddress *saddr;
 197
 198     s->path = g_strdup(qemu_opt_get(opts, "path"));
 199     s->host = g_strdup(qemu_opt_get(opts, "host"));
 200     s->port = g_strdup(qemu_opt_get(opts, "port"));
 201
 202     if (!s->path == !s->host) {
 203         if (s->path) {
 204             error_setg(errp, "path and host may not be used at the same time");
 205         } else {
 206             error_setg(errp, "one of path and host must be specified");
 207         }
 208         return NULL;
 209     }
 210     if (s->port && !s->host) {
 211         error_setg(errp, "port may not be used without host");
 212         return NULL;
 213     }
 214
 215     saddr = g_new0(SocketAddress, 1);
 216
 217     if (s->path) {
 218         UnixSocketAddress *q_unix;
 219         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
 220         q_unix = saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
 221         q_unix->path = g_strdup(s->path);
 222     } else {
 223         InetSocketAddress *inet;
 224
 225         saddr->type = SOCKET_ADDRESS_KIND_INET;
 226         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
 227         inet->host = g_strdup(s->host);
 228         inet->port = g_strdup(s->port);
 229         if (!inet->port) {
 230             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
 231         }
 232     }
 233
 234     s->client.is_unix = saddr->type == SOCKET_ADDRESS_KIND_UNIX;
 235
 236     s->export = g_strdup(qemu_opt_get(opts, "export"));
 237
 238     return saddr;
 239 }
 240
 241 NbdClientSession *nbd_get_client_session(BlockDriverState *bs)
 242 {
 243     BDRVNBDState *s = bs->opaque;
 244     return &s->client;
 245 }
 246
 247 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
 248                                                   Error **errp)
 249 {
 250     QIOChannelSocket *sioc;
 251     Error *local_err = NULL;
 252
 253     sioc = qio_channel_socket_new();
 254
 255     qio_channel_socket_connect_sync(sioc,
 256                                     saddr,
 257                                     &local_err);
 258     if (local_err) {
 259         error_propagate(errp, local_err);
 260         return NULL;
 261     }
 262
 263     qio_channel_set_delay(QIO_CHANNEL(sioc), false);
 264
 265     return sioc;
 266 }
 267
 268
 269 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 270 {
 271     Object *obj;
 272     QCryptoTLSCreds *creds;
 273
 274     obj = object_resolve_path_component(
 275         object_get_objects_root(), id);
 276     if (!obj) {
 277         error_setg(errp, "No TLS credentials with id '%s'",
 278                    id);
 279         return NULL;
 280     }
 281     creds = (QCryptoTLSCreds *)
 282         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 283     if (!creds) {
 284         error_setg(errp, "Object with id '%s' is not TLS credentials",
 285                    id);
 286         return NULL;
 287     }
 288
 289     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 290         error_setg(errp,
 291                    "Expecting TLS credentials with a client endpoint");
 292         return NULL;
 293     }
 294     object_ref(obj);
 295     return creds;
 296 }
 297
 298
 299 static QemuOptsList nbd_runtime_opts = {
 300     .name = "nbd",
 301     .head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
 302     .desc = {
 303         {
 304             .name = "host",
 305             .type = QEMU_OPT_STRING,
 306             .help = "TCP host to connect to",
 307         },
 308         {
 309             .name = "port",
 310             .type = QEMU_OPT_STRING,
 311             .help = "TCP port to connect to",
 312         },
 313         {
 314             .name = "path",
 315             .type = QEMU_OPT_STRING,
 316             .help = "Unix socket path to connect to",
 317         },
 318         {
 319             .name = "export",
 320             .type = QEMU_OPT_STRING,
 321             .help = "Name of the NBD export to open",
 322         },
 323         {
 324             .name = "tls-creds",
 325             .type = QEMU_OPT_STRING,
 326             .help = "ID of the TLS credentials to use",
 327         },
 328     },
 329 };
 330
 331 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 332                     Error **errp)
 333 {
 334     BDRVNBDState *s = bs->opaque;
 335     QemuOpts *opts = NULL;
 336     Error *local_err = NULL;
 337     QIOChannelSocket *sioc = NULL;
 338     SocketAddress *saddr = NULL;
 339     QCryptoTLSCreds *tlscreds = NULL;
 340     const char *hostname = NULL;
 341     int ret = -EINVAL;
 342
 343     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
 344     qemu_opts_absorb_qdict(opts, options, &local_err);
 345     if (local_err) {
 346         error_propagate(errp, local_err);
 347         goto error;
 348     }
 349
 350     /* Pop the config into our state object. Exit if invalid. */
 351     saddr = nbd_config(s, opts, errp);
 352     if (!saddr) {
 353         goto error;
 354     }
 355
 356     s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
 357     if (s->tlscredsid) {
 358         tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
 359         if (!tlscreds) {
 360             goto error;
 361         }
 362
 363         if (saddr->type != SOCKET_ADDRESS_KIND_INET) {
 364             error_setg(errp, "TLS only supported over IP sockets");
 365             goto error;
 366         }
 367         hostname = saddr->u.inet.data->host;
 368     }
 369
 370     /* establish TCP connection, return error if it fails
 371      * TODO: Configurable retry-until-timeout behaviour.
 372      */
 373     sioc = nbd_establish_connection(saddr, errp);
 374     if (!sioc) {
 375         ret = -ECONNREFUSED;
 376         goto error;
 377     }
 378
 379     /* NBD handshake */
 380     ret = nbd_client_init(bs, sioc, s->export,
 381                           tlscreds, hostname, errp);
 382  error:
 383     if (sioc) {
 384         object_unref(OBJECT(sioc));
 385     }
 386     if (tlscreds) {
 387         object_unref(OBJECT(tlscreds));
 388     }
 389     if (ret < 0) {
 390         g_free(s->path);
 391         g_free(s->host);
 392         g_free(s->port);
 393         g_free(s->export);
 394         g_free(s->tlscredsid);
 395     }
 396     qapi_free_SocketAddress(saddr);
 397     qemu_opts_del(opts);
 398     return ret;
 399 }
 400
 401 static int nbd_co_flush(BlockDriverState *bs)
 402 {
 403     return nbd_client_co_flush(bs);
 404 }
 405
 406 static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
 407 {
 408     bs->bl.max_pdiscard = NBD_MAX_BUFFER_SIZE;
 409     bs->bl.max_transfer = NBD_MAX_BUFFER_SIZE;
 410 }
 411
 412 static void nbd_close(BlockDriverState *bs)
 413 {
 414     BDRVNBDState *s = bs->opaque;
 415
 416     nbd_client_close(bs);
 417
 418     g_free(s->path);
 419     g_free(s->host);
 420     g_free(s->port);
 421     g_free(s->export);
 422     g_free(s->tlscredsid);
 423 }
 424
 425 static int64_t nbd_getlength(BlockDriverState *bs)
 426 {
 427     BDRVNBDState *s = bs->opaque;
 428
 429     return s->client.size;
 430 }
 431
 432 static void nbd_detach_aio_context(BlockDriverState *bs)
 433 {
 434     nbd_client_detach_aio_context(bs);
 435 }
 436
 437 static void nbd_attach_aio_context(BlockDriverState *bs,
 438                                    AioContext *new_context)
 439 {
 440     nbd_client_attach_aio_context(bs, new_context);
 441 }
 442
 443 static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
 444 {
 445     BDRVNBDState *s = bs->opaque;
 446     QDict *opts = qdict_new();
 447     const char *port = s->port ?: stringify(NBD_DEFAULT_PORT);
 448
 449     qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str("nbd")));
 450
 451     if (s->path && s->export) {
 452         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 453                  "nbd+unix:///%s?socket=%s", s->export, s->path);
 454     } else if (s->path && !s->export) {
 455         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 456                  "nbd+unix://?socket=%s", s->path);
 457     } else if (!s->path && s->export) {
 458         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 459                  "nbd://%s:%s/%s", s->host, port, s->export);
 460     } else if (!s->path && !s->export) {
 461         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 462                  "nbd://%s:%s", s->host, port);
 463     }
 464
 465     if (s->path) {
 466         qdict_put_obj(opts, "path", QOBJECT(qstring_from_str(s->path)));
 467     } else {
 468         qdict_put_obj(opts, "host", QOBJECT(qstring_from_str(s->host)));
 469         qdict_put_obj(opts, "port", QOBJECT(qstring_from_str(port)));
 470     }
 471     if (s->export) {
 472         qdict_put_obj(opts, "export", QOBJECT(qstring_from_str(s->export)));
 473     }
 474     if (s->tlscredsid) {
 475         qdict_put_obj(opts, "tls-creds",
 476                       QOBJECT(qstring_from_str(s->tlscredsid)));
 477     }
 478
 479     bs->full_open_options = opts;
 480 }
 481
 482 static BlockDriver bdrv_nbd = {
 483     .format_name                = "nbd",
 484     .protocol_name              = "nbd",
 485     .instance_size              = sizeof(BDRVNBDState),
 486     .bdrv_parse_filename        = nbd_parse_filename,
 487     .bdrv_file_open             = nbd_open,
 488     .bdrv_co_preadv             = nbd_client_co_preadv,
 489     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 490     .bdrv_close                 = nbd_close,
 491     .bdrv_co_flush_to_os        = nbd_co_flush,
 492     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 493     .bdrv_refresh_limits        = nbd_refresh_limits,
 494     .bdrv_getlength             = nbd_getlength,
 495     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 496     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 497     .bdrv_refresh_filename      = nbd_refresh_filename,
 498 };
 499
 500 static BlockDriver bdrv_nbd_tcp = {
 501     .format_name                = "nbd",
 502     .protocol_name              = "nbd+tcp",
 503     .instance_size              = sizeof(BDRVNBDState),
 504     .bdrv_parse_filename        = nbd_parse_filename,
 505     .bdrv_file_open             = nbd_open,
 506     .bdrv_co_preadv             = nbd_client_co_preadv,
 507     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 508     .bdrv_close                 = nbd_close,
 509     .bdrv_co_flush_to_os        = nbd_co_flush,
 510     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 511     .bdrv_refresh_limits        = nbd_refresh_limits,
 512     .bdrv_getlength             = nbd_getlength,
 513     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 514     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 515     .bdrv_refresh_filename      = nbd_refresh_filename,
 516 };
 517
 518 static BlockDriver bdrv_nbd_unix = {
 519     .format_name                = "nbd",
 520     .protocol_name              = "nbd+unix",
 521     .instance_size              = sizeof(BDRVNBDState),
 522     .bdrv_parse_filename        = nbd_parse_filename,
 523     .bdrv_file_open             = nbd_open,
 524     .bdrv_co_preadv             = nbd_client_co_preadv,
 525     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 526     .bdrv_close                 = nbd_close,
 527     .bdrv_co_flush_to_os        = nbd_co_flush,
 528     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 529     .bdrv_refresh_limits        = nbd_refresh_limits,
 530     .bdrv_getlength             = nbd_getlength,
 531     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 532     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 533     .bdrv_refresh_filename      = nbd_refresh_filename,
 534 };
 535
 536 static void bdrv_nbd_init(void)
 537 {
 538     bdrv_register(&bdrv_nbd);
 539     bdrv_register(&bdrv_nbd_tcp);
 540     bdrv_register(&bdrv_nbd_unix);
 541 }
 542
 543 block_init(bdrv_nbd_init);