block/nbd.c

   1 /*
   2  * QEMU Block driver for  NBD
   3  *
   4  * Copyright (C) 2008 Bull S.A.S.
   5  *     Author: Laurent Vivier <Laurent.Vivier@bull.net>
   6  *
   7  * Some parts:
   8  *    Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
   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-visit.h"
  36 #include "qapi/qobject-input-visitor.h"
  37 #include "qapi/qobject-output-visitor.h"
  38 #include "qapi/qmp/qdict.h"
  39 #include "qapi/qmp/qjson.h"
  40 #include "qapi/qmp/qint.h"
  41 #include "qapi/qmp/qstring.h"
  42 #include "qemu/cutils.h"
  43
  44 #define EN_OPTSTR ":exportname="
  45
  46 typedef struct BDRVNBDState {
  47     NBDClientSession client;
  48
  49     /* For nbd_refresh_filename() */
  50     SocketAddress *saddr;
  51     char *export, *tlscredsid;
  52 } BDRVNBDState;
  53
  54 static int nbd_parse_uri(const char *filename, QDict *options)
  55 {
  56     URI *uri;
  57     const char *p;
  58     QueryParams *qp = NULL;
  59     int ret = 0;
  60     bool is_unix;
  61
  62     uri = uri_parse(filename);
  63     if (!uri) {
  64         return -EINVAL;
  65     }
  66
  67     /* transport */
  68     if (!strcmp(uri->scheme, "nbd")) {
  69         is_unix = false;
  70     } else if (!strcmp(uri->scheme, "nbd+tcp")) {
  71         is_unix = false;
  72     } else if (!strcmp(uri->scheme, "nbd+unix")) {
  73         is_unix = true;
  74     } else {
  75         ret = -EINVAL;
  76         goto out;
  77     }
  78
  79     p = uri->path ? uri->path : "/";
  80     p += strspn(p, "/");
  81     if (p[0]) {
  82         qdict_put(options, "export", qstring_from_str(p));
  83     }
  84
  85     qp = query_params_parse(uri->query);
  86     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  87         ret = -EINVAL;
  88         goto out;
  89     }
  90
  91     if (is_unix) {
  92         /* nbd+unix:///export?socket=path */
  93         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  94             ret = -EINVAL;
  95             goto out;
  96         }
  97         qdict_put(options, "server.type", qstring_from_str("unix"));
  98         qdict_put(options, "server.data.path",
  99                   qstring_from_str(qp->p[0].value));
 100     } else {
 101         QString *host;
 102         char *port_str;
 103
 104         /* nbd[+tcp]://host[:port]/export */
 105         if (!uri->server) {
 106             ret = -EINVAL;
 107             goto out;
 108         }
 109
 110         /* strip braces from literal IPv6 address */
 111         if (uri->server[0] == '[') {
 112             host = qstring_from_substr(uri->server, 1,
 113                                        strlen(uri->server) - 2);
 114         } else {
 115             host = qstring_from_str(uri->server);
 116         }
 117
 118         qdict_put(options, "server.type", qstring_from_str("inet"));
 119         qdict_put(options, "server.data.host", host);
 120
 121         port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
 122         qdict_put(options, "server.data.port", qstring_from_str(port_str));
 123         g_free(port_str);
 124     }
 125
 126 out:
 127     if (qp) {
 128         query_params_free(qp);
 129     }
 130     uri_free(uri);
 131     return ret;
 132 }
 133
 134 static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
 135 {
 136     const QDictEntry *e;
 137
 138     for (e = qdict_first(options); e; e = qdict_next(options, e)) {
 139         if (!strcmp(e->key, "host") ||
 140             !strcmp(e->key, "port") ||
 141             !strcmp(e->key, "path") ||
 142             !strcmp(e->key, "export") ||
 143             strstart(e->key, "server.", NULL))
 144         {
 145             error_setg(errp, "Option '%s' cannot be used with a file name",
 146                        e->key);
 147             return true;
 148         }
 149     }
 150
 151     return false;
 152 }
 153
 154 static void nbd_parse_filename(const char *filename, QDict *options,
 155                                Error **errp)
 156 {
 157     char *file;
 158     char *export_name;
 159     const char *host_spec;
 160     const char *unixpath;
 161
 162     if (nbd_has_filename_options_conflict(options, errp)) {
 163         return;
 164     }
 165
 166     if (strstr(filename, "://")) {
 167         int ret = nbd_parse_uri(filename, options);
 168         if (ret < 0) {
 169             error_setg(errp, "No valid URL specified");
 170         }
 171         return;
 172     }
 173
 174     file = g_strdup(filename);
 175
 176     export_name = strstr(file, EN_OPTSTR);
 177     if (export_name) {
 178         if (export_name[strlen(EN_OPTSTR)] == 0) {
 179             goto out;
 180         }
 181         export_name[0] = 0; /* truncate 'file' */
 182         export_name += strlen(EN_OPTSTR);
 183
 184         qdict_put(options, "export", qstring_from_str(export_name));
 185     }
 186
 187     /* extract the host_spec - fail if it's not nbd:... */
 188     if (!strstart(file, "nbd:", &host_spec)) {
 189         error_setg(errp, "File name string for NBD must start with 'nbd:'");
 190         goto out;
 191     }
 192
 193     if (!*host_spec) {
 194         goto out;
 195     }
 196
 197     /* are we a UNIX or TCP socket? */
 198     if (strstart(host_spec, "unix:", &unixpath)) {
 199         qdict_put(options, "server.type", qstring_from_str("unix"));
 200         qdict_put(options, "server.data.path", qstring_from_str(unixpath));
 201     } else {
 202         InetSocketAddress *addr = NULL;
 203
 204         addr = inet_parse(host_spec, errp);
 205         if (!addr) {
 206             goto out;
 207         }
 208
 209         qdict_put(options, "server.type", qstring_from_str("inet"));
 210         qdict_put(options, "server.data.host", qstring_from_str(addr->host));
 211         qdict_put(options, "server.data.port", qstring_from_str(addr->port));
 212         qapi_free_InetSocketAddress(addr);
 213     }
 214
 215 out:
 216     g_free(file);
 217 }
 218
 219 static bool nbd_process_legacy_socket_options(QDict *output_options,
 220                                               QemuOpts *legacy_opts,
 221                                               Error **errp)
 222 {
 223     const char *path = qemu_opt_get(legacy_opts, "path");
 224     const char *host = qemu_opt_get(legacy_opts, "host");
 225     const char *port = qemu_opt_get(legacy_opts, "port");
 226     const QDictEntry *e;
 227
 228     if (!path && !host && !port) {
 229         return true;
 230     }
 231
 232     for (e = qdict_first(output_options); e; e = qdict_next(output_options, e))
 233     {
 234         if (strstart(e->key, "server.", NULL)) {
 235             error_setg(errp, "Cannot use 'server' and path/host/port at the "
 236                        "same time");
 237             return false;
 238         }
 239     }
 240
 241     if (path && host) {
 242         error_setg(errp, "path and host may not be used at the same time");
 243         return false;
 244     } else if (path) {
 245         if (port) {
 246             error_setg(errp, "port may not be used without host");
 247             return false;
 248         }
 249
 250         qdict_put(output_options, "server.type", qstring_from_str("unix"));
 251         qdict_put(output_options, "server.data.path", qstring_from_str(path));
 252     } else if (host) {
 253         qdict_put(output_options, "server.type", qstring_from_str("inet"));
 254         qdict_put(output_options, "server.data.host", qstring_from_str(host));
 255         qdict_put(output_options, "server.data.port",
 256                   qstring_from_str(port ?: stringify(NBD_DEFAULT_PORT)));
 257     }
 258
 259     return true;
 260 }
 261
 262 static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, Error **errp)
 263 {
 264     SocketAddress *saddr = NULL;
 265     QDict *addr = NULL;
 266     QObject *crumpled_addr = NULL;
 267     Visitor *iv = NULL;
 268     Error *local_err = NULL;
 269
 270     qdict_extract_subqdict(options, &addr, "server.");
 271     if (!qdict_size(addr)) {
 272         error_setg(errp, "NBD server address missing");
 273         goto done;
 274     }
 275
 276     crumpled_addr = qdict_crumple(addr, errp);
 277     if (!crumpled_addr) {
 278         goto done;
 279     }
 280
 281     iv = qobject_input_visitor_new(crumpled_addr, true);
 282     visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
 283     if (local_err) {
 284         error_propagate(errp, local_err);
 285         goto done;
 286     }
 287
 288     s->client.is_unix = saddr->type == SOCKET_ADDRESS_KIND_UNIX;
 289
 290 done:
 291     QDECREF(addr);
 292     qobject_decref(crumpled_addr);
 293     visit_free(iv);
 294     return saddr;
 295 }
 296
 297 NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
 298 {
 299     BDRVNBDState *s = bs->opaque;
 300     return &s->client;
 301 }
 302
 303 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
 304                                                   Error **errp)
 305 {
 306     QIOChannelSocket *sioc;
 307     Error *local_err = NULL;
 308
 309     sioc = qio_channel_socket_new();
 310     qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
 311
 312     qio_channel_socket_connect_sync(sioc,
 313                                     saddr,
 314                                     &local_err);
 315     if (local_err) {
 316         error_propagate(errp, local_err);
 317         return NULL;
 318     }
 319
 320     qio_channel_set_delay(QIO_CHANNEL(sioc), false);
 321
 322     return sioc;
 323 }
 324
 325
 326 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 327 {
 328     Object *obj;
 329     QCryptoTLSCreds *creds;
 330
 331     obj = object_resolve_path_component(
 332         object_get_objects_root(), id);
 333     if (!obj) {
 334         error_setg(errp, "No TLS credentials with id '%s'",
 335                    id);
 336         return NULL;
 337     }
 338     creds = (QCryptoTLSCreds *)
 339         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 340     if (!creds) {
 341         error_setg(errp, "Object with id '%s' is not TLS credentials",
 342                    id);
 343         return NULL;
 344     }
 345
 346     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 347         error_setg(errp,
 348                    "Expecting TLS credentials with a client endpoint");
 349         return NULL;
 350     }
 351     object_ref(obj);
 352     return creds;
 353 }
 354
 355
 356 static QemuOptsList nbd_runtime_opts = {
 357     .name = "nbd",
 358     .head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
 359     .desc = {
 360         {
 361             .name = "host",
 362             .type = QEMU_OPT_STRING,
 363             .help = "TCP host to connect to",
 364         },
 365         {
 366             .name = "port",
 367             .type = QEMU_OPT_STRING,
 368             .help = "TCP port to connect to",
 369         },
 370         {
 371             .name = "path",
 372             .type = QEMU_OPT_STRING,
 373             .help = "Unix socket path to connect to",
 374         },
 375         {
 376             .name = "export",
 377             .type = QEMU_OPT_STRING,
 378             .help = "Name of the NBD export to open",
 379         },
 380         {
 381             .name = "tls-creds",
 382             .type = QEMU_OPT_STRING,
 383             .help = "ID of the TLS credentials to use",
 384         },
 385     },
 386 };
 387
 388 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 389                     Error **errp)
 390 {
 391     BDRVNBDState *s = bs->opaque;
 392     QemuOpts *opts = NULL;
 393     Error *local_err = NULL;
 394     QIOChannelSocket *sioc = NULL;
 395     QCryptoTLSCreds *tlscreds = NULL;
 396     const char *hostname = NULL;
 397     int ret = -EINVAL;
 398
 399     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
 400     qemu_opts_absorb_qdict(opts, options, &local_err);
 401     if (local_err) {
 402         error_propagate(errp, local_err);
 403         goto error;
 404     }
 405
 406     /* Translate @host, @port, and @path to a SocketAddress */
 407     if (!nbd_process_legacy_socket_options(options, opts, errp)) {
 408         goto error;
 409     }
 410
 411     /* Pop the config into our state object. Exit if invalid. */
 412     s->saddr = nbd_config(s, options, errp);
 413     if (!s->saddr) {
 414         goto error;
 415     }
 416
 417     s->export = g_strdup(qemu_opt_get(opts, "export"));
 418
 419     s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
 420     if (s->tlscredsid) {
 421         tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
 422         if (!tlscreds) {
 423             goto error;
 424         }
 425
 426         if (s->saddr->type != SOCKET_ADDRESS_KIND_INET) {
 427             error_setg(errp, "TLS only supported over IP sockets");
 428             goto error;
 429         }
 430         hostname = s->saddr->u.inet.data->host;
 431     }
 432
 433     /* establish TCP connection, return error if it fails
 434      * TODO: Configurable retry-until-timeout behaviour.
 435      */
 436     sioc = nbd_establish_connection(s->saddr, errp);
 437     if (!sioc) {
 438         ret = -ECONNREFUSED;
 439         goto error;
 440     }
 441
 442     /* NBD handshake */
 443     ret = nbd_client_init(bs, sioc, s->export,
 444                           tlscreds, hostname, errp);
 445  error:
 446     if (sioc) {
 447         object_unref(OBJECT(sioc));
 448     }
 449     if (tlscreds) {
 450         object_unref(OBJECT(tlscreds));
 451     }
 452     if (ret < 0) {
 453         qapi_free_SocketAddress(s->saddr);
 454         g_free(s->export);
 455         g_free(s->tlscredsid);
 456     }
 457     qemu_opts_del(opts);
 458     return ret;
 459 }
 460
 461 static int nbd_co_flush(BlockDriverState *bs)
 462 {
 463     return nbd_client_co_flush(bs);
 464 }
 465
 466 static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
 467 {
 468     bs->bl.max_pdiscard = NBD_MAX_BUFFER_SIZE;
 469     bs->bl.max_pwrite_zeroes = NBD_MAX_BUFFER_SIZE;
 470     bs->bl.max_transfer = NBD_MAX_BUFFER_SIZE;
 471 }
 472
 473 static void nbd_close(BlockDriverState *bs)
 474 {
 475     BDRVNBDState *s = bs->opaque;
 476
 477     nbd_client_close(bs);
 478
 479     qapi_free_SocketAddress(s->saddr);
 480     g_free(s->export);
 481     g_free(s->tlscredsid);
 482 }
 483
 484 static int64_t nbd_getlength(BlockDriverState *bs)
 485 {
 486     BDRVNBDState *s = bs->opaque;
 487
 488     return s->client.size;
 489 }
 490
 491 static void nbd_detach_aio_context(BlockDriverState *bs)
 492 {
 493     nbd_client_detach_aio_context(bs);
 494 }
 495
 496 static void nbd_attach_aio_context(BlockDriverState *bs,
 497                                    AioContext *new_context)
 498 {
 499     nbd_client_attach_aio_context(bs, new_context);
 500 }
 501
 502 static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
 503 {
 504     BDRVNBDState *s = bs->opaque;
 505     QDict *opts = qdict_new();
 506     QObject *saddr_qdict;
 507     Visitor *ov;
 508     const char *host = NULL, *port = NULL, *path = NULL;
 509
 510     if (s->saddr->type == SOCKET_ADDRESS_KIND_INET) {
 511         const InetSocketAddress *inet = s->saddr->u.inet.data;
 512         if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
 513             host = inet->host;
 514             port = inet->port;
 515         }
 516     } else if (s->saddr->type == SOCKET_ADDRESS_KIND_UNIX) {
 517         path = s->saddr->u.q_unix.data->path;
 518     }
 519
 520     qdict_put(opts, "driver", qstring_from_str("nbd"));
 521
 522     if (path && s->export) {
 523         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 524                  "nbd+unix:///%s?socket=%s", s->export, path);
 525     } else if (path && !s->export) {
 526         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 527                  "nbd+unix://?socket=%s", path);
 528     } else if (host && s->export) {
 529         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 530                  "nbd://%s:%s/%s", host, port, s->export);
 531     } else if (host && !s->export) {
 532         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 533                  "nbd://%s:%s", host, port);
 534     }
 535
 536     ov = qobject_output_visitor_new(&saddr_qdict);
 537     visit_type_SocketAddress(ov, NULL, &s->saddr, &error_abort);
 538     visit_complete(ov, &saddr_qdict);
 539     visit_free(ov);
 540     assert(qobject_type(saddr_qdict) == QTYPE_QDICT);
 541
 542     qdict_put_obj(opts, "server", saddr_qdict);
 543
 544     if (s->export) {
 545         qdict_put(opts, "export", qstring_from_str(s->export));
 546     }
 547     if (s->tlscredsid) {
 548         qdict_put(opts, "tls-creds", qstring_from_str(s->tlscredsid));
 549     }
 550
 551     qdict_flatten(opts);
 552     bs->full_open_options = opts;
 553 }
 554
 555 static BlockDriver bdrv_nbd = {
 556     .format_name                = "nbd",
 557     .protocol_name              = "nbd",
 558     .instance_size              = sizeof(BDRVNBDState),
 559     .bdrv_parse_filename        = nbd_parse_filename,
 560     .bdrv_file_open             = nbd_open,
 561     .bdrv_co_preadv             = nbd_client_co_preadv,
 562     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 563     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 564     .bdrv_close                 = nbd_close,
 565     .bdrv_co_flush_to_os        = nbd_co_flush,
 566     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 567     .bdrv_refresh_limits        = nbd_refresh_limits,
 568     .bdrv_getlength             = nbd_getlength,
 569     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 570     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 571     .bdrv_refresh_filename      = nbd_refresh_filename,
 572 };
 573
 574 static BlockDriver bdrv_nbd_tcp = {
 575     .format_name                = "nbd",
 576     .protocol_name              = "nbd+tcp",
 577     .instance_size              = sizeof(BDRVNBDState),
 578     .bdrv_parse_filename        = nbd_parse_filename,
 579     .bdrv_file_open             = nbd_open,
 580     .bdrv_co_preadv             = nbd_client_co_preadv,
 581     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 582     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 583     .bdrv_close                 = nbd_close,
 584     .bdrv_co_flush_to_os        = nbd_co_flush,
 585     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 586     .bdrv_refresh_limits        = nbd_refresh_limits,
 587     .bdrv_getlength             = nbd_getlength,
 588     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 589     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 590     .bdrv_refresh_filename      = nbd_refresh_filename,
 591 };
 592
 593 static BlockDriver bdrv_nbd_unix = {
 594     .format_name                = "nbd",
 595     .protocol_name              = "nbd+unix",
 596     .instance_size              = sizeof(BDRVNBDState),
 597     .bdrv_parse_filename        = nbd_parse_filename,
 598     .bdrv_file_open             = nbd_open,
 599     .bdrv_co_preadv             = nbd_client_co_preadv,
 600     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 601     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 602     .bdrv_close                 = nbd_close,
 603     .bdrv_co_flush_to_os        = nbd_co_flush,
 604     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 605     .bdrv_refresh_limits        = nbd_refresh_limits,
 606     .bdrv_getlength             = nbd_getlength,
 607     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 608     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 609     .bdrv_refresh_filename      = nbd_refresh_filename,
 610 };
 611
 612 static void bdrv_nbd_init(void)
 613 {
 614     bdrv_register(&bdrv_nbd);
 615     bdrv_register(&bdrv_nbd_tcp);
 616     bdrv_register(&bdrv_nbd_unix);
 617 }
 618
 619 block_init(bdrv_nbd_init);