nbd/server.c

   1 /*
   2  *  Copyright (C) 2016-2017 Red Hat, Inc.
   3  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   4  *
   5  *  Network Block Device Server Side
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; under version 2 of the License.
  10  *
  11  *  This program 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
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qapi/error.h"
  22 #include "trace.h"
  23 #include "nbd-internal.h"
  24
  25 static int system_errno_to_nbd_errno(int err)
  26 {
  27     switch (err) {
  28     case 0:
  29         return NBD_SUCCESS;
  30     case EPERM:
  31     case EROFS:
  32         return NBD_EPERM;
  33     case EIO:
  34         return NBD_EIO;
  35     case ENOMEM:
  36         return NBD_ENOMEM;
  37 #ifdef EDQUOT
  38     case EDQUOT:
  39 #endif
  40     case EFBIG:
  41     case ENOSPC:
  42         return NBD_ENOSPC;
  43     case ESHUTDOWN:
  44         return NBD_ESHUTDOWN;
  45     case EINVAL:
  46     default:
  47         return NBD_EINVAL;
  48     }
  49 }
  50
  51 /* Definitions for opaque data types */
  52
  53 typedef struct NBDRequestData NBDRequestData;
  54
  55 struct NBDRequestData {
  56     QSIMPLEQ_ENTRY(NBDRequestData) entry;
  57     NBDClient *client;
  58     uint8_t *data;
  59     bool complete;
  60 };
  61
  62 struct NBDExport {
  63     int refcount;
  64     void (*close)(NBDExport *exp);
  65
  66     BlockBackend *blk;
  67     char *name;
  68     char *description;
  69     off_t dev_offset;
  70     off_t size;
  71     uint16_t nbdflags;
  72     QTAILQ_HEAD(, NBDClient) clients;
  73     QTAILQ_ENTRY(NBDExport) next;
  74
  75     AioContext *ctx;
  76
  77     BlockBackend *eject_notifier_blk;
  78     Notifier eject_notifier;
  79 };
  80
  81 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
  82
  83 struct NBDClient {
  84     int refcount;
  85     void (*close_fn)(NBDClient *client, bool negotiated);
  86
  87     NBDExport *exp;
  88     QCryptoTLSCreds *tlscreds;
  89     char *tlsaclname;
  90     QIOChannelSocket *sioc; /* The underlying data channel */
  91     QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
  92
  93     Coroutine *recv_coroutine;
  94
  95     CoMutex send_lock;
  96     Coroutine *send_coroutine;
  97
  98     QTAILQ_ENTRY(NBDClient) next;
  99     int nb_requests;
 100     bool closing;
 101 };
 102
 103 /* That's all folks */
 104
 105 static void nbd_client_receive_next_request(NBDClient *client);
 106
 107 /* Basic flow for negotiation
 108
 109    Server         Client
 110    Negotiate
 111
 112    or
 113
 114    Server         Client
 115    Negotiate #1
 116                   Option
 117    Negotiate #2
 118
 119    ----
 120
 121    followed by
 122
 123    Server         Client
 124                   Request
 125    Response
 126                   Request
 127    Response
 128                   ...
 129    ...
 130                   Request (type == 2)
 131
 132 */
 133
 134 /* Send a reply header, including length, but no payload.
 135  * Return -errno on error, 0 on success. */
 136 static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
 137                                       uint32_t opt, uint32_t len, Error **errp)
 138 {
 139     uint64_t magic;
 140
 141     trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt),
 142                                      type, nbd_rep_lookup(type), len);
 143
 144     assert(len < NBD_MAX_BUFFER_SIZE);
 145     magic = cpu_to_be64(NBD_REP_MAGIC);
 146     if (nbd_write(ioc, &magic, sizeof(magic), errp) < 0) {
 147         error_prepend(errp, "write failed (rep magic): ");
 148         return -EINVAL;
 149     }
 150
 151     opt = cpu_to_be32(opt);
 152     if (nbd_write(ioc, &opt, sizeof(opt), errp) < 0) {
 153         error_prepend(errp, "write failed (rep opt): ");
 154         return -EINVAL;
 155     }
 156
 157     type = cpu_to_be32(type);
 158     if (nbd_write(ioc, &type, sizeof(type), errp) < 0) {
 159         error_prepend(errp, "write failed (rep type): ");
 160         return -EINVAL;
 161     }
 162
 163     len = cpu_to_be32(len);
 164     if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
 165         error_prepend(errp, "write failed (rep data length): ");
 166         return -EINVAL;
 167     }
 168     return 0;
 169 }
 170
 171 /* Send a reply header with default 0 length.
 172  * Return -errno on error, 0 on success. */
 173 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt,
 174                                   Error **errp)
 175 {
 176     return nbd_negotiate_send_rep_len(ioc, type, opt, 0, errp);
 177 }
 178
 179 /* Send an error reply.
 180  * Return -errno on error, 0 on success. */
 181 static int GCC_FMT_ATTR(5, 6)
 182 nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
 183                            uint32_t opt, Error **errp, const char *fmt, ...)
 184 {
 185     va_list va;
 186     char *msg;
 187     int ret;
 188     size_t len;
 189
 190     va_start(va, fmt);
 191     msg = g_strdup_vprintf(fmt, va);
 192     va_end(va);
 193     len = strlen(msg);
 194     assert(len < 4096);
 195     trace_nbd_negotiate_send_rep_err(msg);
 196     ret = nbd_negotiate_send_rep_len(ioc, type, opt, len, errp);
 197     if (ret < 0) {
 198         goto out;
 199     }
 200     if (nbd_write(ioc, msg, len, errp) < 0) {
 201         error_prepend(errp, "write failed (error message): ");
 202         ret = -EIO;
 203     } else {
 204         ret = 0;
 205     }
 206
 207 out:
 208     g_free(msg);
 209     return ret;
 210 }
 211
 212 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
 213  * Return -errno on error, 0 on success. */
 214 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp,
 215                                        Error **errp)
 216 {
 217     size_t name_len, desc_len;
 218     uint32_t len;
 219     const char *name = exp->name ? exp->name : "";
 220     const char *desc = exp->description ? exp->description : "";
 221     int ret;
 222
 223     trace_nbd_negotiate_send_rep_list(name, desc);
 224     name_len = strlen(name);
 225     desc_len = strlen(desc);
 226     len = name_len + desc_len + sizeof(len);
 227     ret = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len,
 228                                      errp);
 229     if (ret < 0) {
 230         return ret;
 231     }
 232
 233     len = cpu_to_be32(name_len);
 234     if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
 235         error_prepend(errp, "write failed (name length): ");
 236         return -EINVAL;
 237     }
 238
 239     if (nbd_write(ioc, name, name_len, errp) < 0) {
 240         error_prepend(errp, "write failed (name buffer): ");
 241         return -EINVAL;
 242     }
 243
 244     if (nbd_write(ioc, desc, desc_len, errp) < 0) {
 245         error_prepend(errp, "write failed (description buffer): ");
 246         return -EINVAL;
 247     }
 248
 249     return 0;
 250 }
 251
 252 /* Process the NBD_OPT_LIST command, with a potential series of replies.
 253  * Return -errno on error, 0 on success. */
 254 static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length,
 255                                      Error **errp)
 256 {
 257     NBDExport *exp;
 258
 259     if (length) {
 260         if (nbd_drop(client->ioc, length, errp) < 0) {
 261             return -EIO;
 262         }
 263         return nbd_negotiate_send_rep_err(client->ioc,
 264                                           NBD_REP_ERR_INVALID, NBD_OPT_LIST,
 265                                           errp,
 266                                           "OPT_LIST should not have length");
 267     }
 268
 269     /* For each export, send a NBD_REP_SERVER reply. */
 270     QTAILQ_FOREACH(exp, &exports, next) {
 271         if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) {
 272             return -EINVAL;
 273         }
 274     }
 275     /* Finish with a NBD_REP_ACK. */
 276     return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST, errp);
 277 }
 278
 279 /* Send a reply to NBD_OPT_EXPORT_NAME.
 280  * Return -errno on error, 0 on success. */
 281 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
 282                                             uint16_t myflags, bool no_zeroes,
 283                                             Error **errp)
 284 {
 285     char name[NBD_MAX_NAME_SIZE + 1];
 286     char buf[8 + 4 + 124] = "";
 287     size_t len;
 288     int ret;
 289
 290     /* Client sends:
 291         [20 ..  xx]   export name (length bytes)
 292      */
 293     trace_nbd_negotiate_handle_export_name();
 294     if (length >= sizeof(name)) {
 295         error_setg(errp, "Bad length received");
 296         return -EINVAL;
 297     }
 298     if (nbd_read(client->ioc, name, length, errp) < 0) {
 299         error_prepend(errp, "read failed: ");
 300         return -EINVAL;
 301     }
 302     name[length] = '\0';
 303
 304     trace_nbd_negotiate_handle_export_name_request(name);
 305
 306     client->exp = nbd_export_find(name);
 307     if (!client->exp) {
 308         error_setg(errp, "export not found");
 309         return -EINVAL;
 310     }
 311
 312     trace_nbd_negotiate_new_style_size_flags(client->exp->size,
 313                                              client->exp->nbdflags | myflags);
 314     stq_be_p(buf, client->exp->size);
 315     stw_be_p(buf + 8, client->exp->nbdflags | myflags);
 316     len = no_zeroes ? 10 : sizeof(buf);
 317     ret = nbd_write(client->ioc, buf, len, errp);
 318     if (ret < 0) {
 319         error_prepend(errp, "write failed: ");
 320         return ret;
 321     }
 322
 323     QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
 324     nbd_export_get(client->exp);
 325
 326     return 0;
 327 }
 328
 329 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
 330  * The buffer does NOT include the info type prefix.
 331  * Return -errno on error, 0 if ready to send more. */
 332 static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt,
 333                                    uint16_t info, uint32_t length, void *buf,
 334                                    Error **errp)
 335 {
 336     int rc;
 337
 338     trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
 339     rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt,
 340                                     sizeof(info) + length, errp);
 341     if (rc < 0) {
 342         return rc;
 343     }
 344     cpu_to_be16s(&info);
 345     if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
 346         return -EIO;
 347     }
 348     if (nbd_write(client->ioc, buf, length, errp) < 0) {
 349         return -EIO;
 350     }
 351     return 0;
 352 }
 353
 354 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
 355  * Return -errno on error, 0 if ready for next option, and 1 to move
 356  * into transmission phase.  */
 357 static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
 358                                      uint32_t opt, uint16_t myflags,
 359                                      Error **errp)
 360 {
 361     int rc;
 362     char name[NBD_MAX_NAME_SIZE + 1];
 363     NBDExport *exp;
 364     uint16_t requests;
 365     uint16_t request;
 366     uint32_t namelen;
 367     bool sendname = false;
 368     bool blocksize = false;
 369     uint32_t sizes[3];
 370     char buf[sizeof(uint64_t) + sizeof(uint16_t)];
 371     const char *msg;
 372
 373     /* Client sends:
 374         4 bytes: L, name length (can be 0)
 375         L bytes: export name
 376         2 bytes: N, number of requests (can be 0)
 377         N * 2 bytes: N requests
 378     */
 379     if (length < sizeof(namelen) + sizeof(requests)) {
 380         msg = "overall request too short";
 381         goto invalid;
 382     }
 383     if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) {
 384         return -EIO;
 385     }
 386     be32_to_cpus(&namelen);
 387     length -= sizeof(namelen);
 388     if (namelen > length - sizeof(requests) || (length - namelen) % 2) {
 389         msg = "name length is incorrect";
 390         goto invalid;
 391     }
 392     if (nbd_read(client->ioc, name, namelen, errp) < 0) {
 393         return -EIO;
 394     }
 395     name[namelen] = '\0';
 396     length -= namelen;
 397     trace_nbd_negotiate_handle_export_name_request(name);
 398
 399     if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) {
 400         return -EIO;
 401     }
 402     be16_to_cpus(&requests);
 403     length -= sizeof(requests);
 404     trace_nbd_negotiate_handle_info_requests(requests);
 405     if (requests != length / sizeof(request)) {
 406         msg = "incorrect number of  requests for overall length";
 407         goto invalid;
 408     }
 409     while (requests--) {
 410         if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) {
 411             return -EIO;
 412         }
 413         be16_to_cpus(&request);
 414         length -= sizeof(request);
 415         trace_nbd_negotiate_handle_info_request(request,
 416                                                 nbd_info_lookup(request));
 417         /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
 418          * everything else is either a request we don't know or
 419          * something we send regardless of request */
 420         switch (request) {
 421         case NBD_INFO_NAME:
 422             sendname = true;
 423             break;
 424         case NBD_INFO_BLOCK_SIZE:
 425             blocksize = true;
 426             break;
 427         }
 428     }
 429
 430     exp = nbd_export_find(name);
 431     if (!exp) {
 432         return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN,
 433                                           opt, errp, "export '%s' not present",
 434                                           name);
 435     }
 436
 437     /* Don't bother sending NBD_INFO_NAME unless client requested it */
 438     if (sendname) {
 439         rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, name,
 440                                      errp);
 441         if (rc < 0) {
 442             return rc;
 443         }
 444     }
 445
 446     /* Send NBD_INFO_DESCRIPTION only if available, regardless of
 447      * client request */
 448     if (exp->description) {
 449         size_t len = strlen(exp->description);
 450
 451         rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION,
 452                                      len, exp->description, errp);
 453         if (rc < 0) {
 454             return rc;
 455         }
 456     }
 457
 458     /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
 459      * according to whether the client requested it, and according to
 460      * whether this is OPT_INFO or OPT_GO. */
 461     /* minimum - 1 for back-compat, or 512 if client is new enough.
 462      * TODO: consult blk_bs(blk)->bl.request_alignment? */
 463     sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
 464     /* preferred - Hard-code to 4096 for now.
 465      * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
 466     sizes[1] = 4096;
 467     /* maximum - At most 32M, but smaller as appropriate. */
 468     sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
 469     trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
 470     cpu_to_be32s(&sizes[0]);
 471     cpu_to_be32s(&sizes[1]);
 472     cpu_to_be32s(&sizes[2]);
 473     rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE,
 474                                  sizeof(sizes), sizes, errp);
 475     if (rc < 0) {
 476         return rc;
 477     }
 478
 479     /* Send NBD_INFO_EXPORT always */
 480     trace_nbd_negotiate_new_style_size_flags(exp->size,
 481                                              exp->nbdflags | myflags);
 482     stq_be_p(buf, exp->size);
 483     stw_be_p(buf + 8, exp->nbdflags | myflags);
 484     rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT,
 485                                  sizeof(buf), buf, errp);
 486     if (rc < 0) {
 487         return rc;
 488     }
 489
 490     /* If the client is just asking for NBD_OPT_INFO, but forgot to
 491      * request block sizes, return an error.
 492      * TODO: consult blk_bs(blk)->request_align, and only error if it
 493      * is not 1? */
 494     if (opt == NBD_OPT_INFO && !blocksize) {
 495         return nbd_negotiate_send_rep_err(client->ioc,
 496                                           NBD_REP_ERR_BLOCK_SIZE_REQD, opt,
 497                                           errp,
 498                                           "request NBD_INFO_BLOCK_SIZE to "
 499                                           "use this export");
 500     }
 501
 502     /* Final reply */
 503     rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp);
 504     if (rc < 0) {
 505         return rc;
 506     }
 507
 508     if (opt == NBD_OPT_GO) {
 509         client->exp = exp;
 510         QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
 511         nbd_export_get(client->exp);
 512         rc = 1;
 513     }
 514     return rc;
 515
 516  invalid:
 517     if (nbd_drop(client->ioc, length, errp) < 0) {
 518         return -EIO;
 519     }
 520     return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt,
 521                                       errp, "%s", msg);
 522 }
 523
 524
 525 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
 526  * new channel for all further (now-encrypted) communication. */
 527 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
 528                                                  uint32_t length,
 529                                                  Error **errp)
 530 {
 531     QIOChannel *ioc;
 532     QIOChannelTLS *tioc;
 533     struct NBDTLSHandshakeData data = { 0 };
 534
 535     trace_nbd_negotiate_handle_starttls();
 536     ioc = client->ioc;
 537     if (length) {
 538         if (nbd_drop(ioc, length, errp) < 0) {
 539             return NULL;
 540         }
 541         nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
 542                                    errp,
 543                                    "OPT_STARTTLS should not have length");
 544         return NULL;
 545     }
 546
 547     if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
 548                                NBD_OPT_STARTTLS, errp) < 0) {
 549         return NULL;
 550     }
 551
 552     tioc = qio_channel_tls_new_server(ioc,
 553                                       client->tlscreds,
 554                                       client->tlsaclname,
 555                                       errp);
 556     if (!tioc) {
 557         return NULL;
 558     }
 559
 560     qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
 561     trace_nbd_negotiate_handle_starttls_handshake();
 562     data.loop = g_main_loop_new(g_main_context_default(), FALSE);
 563     qio_channel_tls_handshake(tioc,
 564                               nbd_tls_handshake,
 565                               &data,
 566                               NULL);
 567
 568     if (!data.complete) {
 569         g_main_loop_run(data.loop);
 570     }
 571     g_main_loop_unref(data.loop);
 572     if (data.error) {
 573         object_unref(OBJECT(tioc));
 574         error_propagate(errp, data.error);
 575         return NULL;
 576     }
 577
 578     return QIO_CHANNEL(tioc);
 579 }
 580
 581 /* nbd_negotiate_options
 582  * Process all NBD_OPT_* client option commands, during fixed newstyle
 583  * negotiation.
 584  * Return:
 585  * -errno  on error, errp is set
 586  * 0       on successful negotiation, errp is not set
 587  * 1       if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
 588  *         errp is not set
 589  */
 590 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
 591                                  Error **errp)
 592 {
 593     uint32_t flags;
 594     bool fixedNewstyle = false;
 595     bool no_zeroes = false;
 596
 597     /* Client sends:
 598         [ 0 ..   3]   client flags
 599
 600        Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
 601         [ 0 ..   7]   NBD_OPTS_MAGIC
 602         [ 8 ..  11]   NBD option
 603         [12 ..  15]   Data length
 604         ...           Rest of request
 605
 606         [ 0 ..   7]   NBD_OPTS_MAGIC
 607         [ 8 ..  11]   Second NBD option
 608         [12 ..  15]   Data length
 609         ...           Rest of request
 610     */
 611
 612     if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
 613         error_prepend(errp, "read failed: ");
 614         return -EIO;
 615     }
 616     be32_to_cpus(&flags);
 617     trace_nbd_negotiate_options_flags(flags);
 618     if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
 619         fixedNewstyle = true;
 620         flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
 621     }
 622     if (flags & NBD_FLAG_C_NO_ZEROES) {
 623         no_zeroes = true;
 624         flags &= ~NBD_FLAG_C_NO_ZEROES;
 625     }
 626     if (flags != 0) {
 627         error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
 628         return -EINVAL;
 629     }
 630
 631     while (1) {
 632         int ret;
 633         uint32_t option, length;
 634         uint64_t magic;
 635
 636         if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
 637             error_prepend(errp, "read failed: ");
 638             return -EINVAL;
 639         }
 640         magic = be64_to_cpu(magic);
 641         trace_nbd_negotiate_options_check_magic(magic);
 642         if (magic != NBD_OPTS_MAGIC) {
 643             error_setg(errp, "Bad magic received");
 644             return -EINVAL;
 645         }
 646
 647         if (nbd_read(client->ioc, &option,
 648                      sizeof(option), errp) < 0) {
 649             error_prepend(errp, "read failed: ");
 650             return -EINVAL;
 651         }
 652         option = be32_to_cpu(option);
 653
 654         if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
 655             error_prepend(errp, "read failed: ");
 656             return -EINVAL;
 657         }
 658         length = be32_to_cpu(length);
 659
 660         trace_nbd_negotiate_options_check_option(option,
 661                                                  nbd_opt_lookup(option));
 662         if (client->tlscreds &&
 663             client->ioc == (QIOChannel *)client->sioc) {
 664             QIOChannel *tioc;
 665             if (!fixedNewstyle) {
 666                 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
 667                 return -EINVAL;
 668             }
 669             switch (option) {
 670             case NBD_OPT_STARTTLS:
 671                 tioc = nbd_negotiate_handle_starttls(client, length, errp);
 672                 if (!tioc) {
 673                     return -EIO;
 674                 }
 675                 object_unref(OBJECT(client->ioc));
 676                 client->ioc = QIO_CHANNEL(tioc);
 677                 break;
 678
 679             case NBD_OPT_EXPORT_NAME:
 680                 /* No way to return an error to client, so drop connection */
 681                 error_setg(errp, "Option 0x%x not permitted before TLS",
 682                            option);
 683                 return -EINVAL;
 684
 685             default:
 686                 if (nbd_drop(client->ioc, length, errp) < 0) {
 687                     return -EIO;
 688                 }
 689                 ret = nbd_negotiate_send_rep_err(client->ioc,
 690                                                  NBD_REP_ERR_TLS_REQD,
 691                                                  option, errp,
 692                                                  "Option 0x%" PRIx32
 693                                                  "not permitted before TLS",
 694                                                  option);
 695                 if (ret < 0) {
 696                     return ret;
 697                 }
 698                 /* Let the client keep trying, unless they asked to
 699                  * quit. In this mode, we've already sent an error, so
 700                  * we can't ack the abort.  */
 701                 if (option == NBD_OPT_ABORT) {
 702                     return 1;
 703                 }
 704                 break;
 705             }
 706         } else if (fixedNewstyle) {
 707             switch (option) {
 708             case NBD_OPT_LIST:
 709                 ret = nbd_negotiate_handle_list(client, length, errp);
 710                 if (ret < 0) {
 711                     return ret;
 712                 }
 713                 break;
 714
 715             case NBD_OPT_ABORT:
 716                 /* NBD spec says we must try to reply before
 717                  * disconnecting, but that we must also tolerate
 718                  * guests that don't wait for our reply. */
 719                 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL);
 720                 return 1;
 721
 722             case NBD_OPT_EXPORT_NAME:
 723                 return nbd_negotiate_handle_export_name(client, length,
 724                                                         myflags, no_zeroes,
 725                                                         errp);
 726
 727             case NBD_OPT_INFO:
 728             case NBD_OPT_GO:
 729                 ret = nbd_negotiate_handle_info(client, length, option,
 730                                                 myflags, errp);
 731                 if (ret == 1) {
 732                     assert(option == NBD_OPT_GO);
 733                     return 0;
 734                 }
 735                 if (ret) {
 736                     return ret;
 737                 }
 738                 break;
 739
 740             case NBD_OPT_STARTTLS:
 741                 if (nbd_drop(client->ioc, length, errp) < 0) {
 742                     return -EIO;
 743                 }
 744                 if (client->tlscreds) {
 745                     ret = nbd_negotiate_send_rep_err(client->ioc,
 746                                                      NBD_REP_ERR_INVALID,
 747                                                      option, errp,
 748                                                      "TLS already enabled");
 749                 } else {
 750                     ret = nbd_negotiate_send_rep_err(client->ioc,
 751                                                      NBD_REP_ERR_POLICY,
 752                                                      option, errp,
 753                                                      "TLS not configured");
 754                 }
 755                 if (ret < 0) {
 756                     return ret;
 757                 }
 758                 break;
 759             default:
 760                 if (nbd_drop(client->ioc, length, errp) < 0) {
 761                     return -EIO;
 762                 }
 763                 ret = nbd_negotiate_send_rep_err(client->ioc,
 764                                                  NBD_REP_ERR_UNSUP,
 765                                                  option, errp,
 766                                                  "Unsupported option 0x%"
 767                                                  PRIx32 " (%s)", option,
 768                                                  nbd_opt_lookup(option));
 769                 if (ret < 0) {
 770                     return ret;
 771                 }
 772                 break;
 773             }
 774         } else {
 775             /*
 776              * If broken new-style we should drop the connection
 777              * for anything except NBD_OPT_EXPORT_NAME
 778              */
 779             switch (option) {
 780             case NBD_OPT_EXPORT_NAME:
 781                 return nbd_negotiate_handle_export_name(client, length,
 782                                                         myflags, no_zeroes,
 783                                                         errp);
 784
 785             default:
 786                 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)",
 787                            option, nbd_opt_lookup(option));
 788                 return -EINVAL;
 789             }
 790         }
 791     }
 792 }
 793
 794 /* nbd_negotiate
 795  * Return:
 796  * -errno  on error, errp is set
 797  * 0       on successful negotiation, errp is not set
 798  * 1       if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
 799  *         errp is not set
 800  */
 801 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
 802 {
 803     char buf[8 + 8 + 8 + 128];
 804     int ret;
 805     const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
 806                               NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
 807                               NBD_FLAG_SEND_WRITE_ZEROES);
 808     bool oldStyle;
 809
 810     /* Old style negotiation header without options
 811         [ 0 ..   7]   passwd       ("NBDMAGIC")
 812         [ 8 ..  15]   magic        (NBD_CLIENT_MAGIC)
 813         [16 ..  23]   size
 814         [24 ..  25]   server flags (0)
 815         [26 ..  27]   export flags
 816         [28 .. 151]   reserved     (0)
 817
 818        New style negotiation header with options
 819         [ 0 ..   7]   passwd       ("NBDMAGIC")
 820         [ 8 ..  15]   magic        (NBD_OPTS_MAGIC)
 821         [16 ..  17]   server flags (0)
 822         ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
 823      */
 824
 825     qio_channel_set_blocking(client->ioc, false, NULL);
 826
 827     trace_nbd_negotiate_begin();
 828     memset(buf, 0, sizeof(buf));
 829     memcpy(buf, "NBDMAGIC", 8);
 830
 831     oldStyle = client->exp != NULL && !client->tlscreds;
 832     if (oldStyle) {
 833         trace_nbd_negotiate_old_style(client->exp->size,
 834                                       client->exp->nbdflags | myflags);
 835         stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
 836         stq_be_p(buf + 16, client->exp->size);
 837         stw_be_p(buf + 26, client->exp->nbdflags | myflags);
 838
 839         if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) {
 840             error_prepend(errp, "write failed: ");
 841             return -EINVAL;
 842         }
 843     } else {
 844         stq_be_p(buf + 8, NBD_OPTS_MAGIC);
 845         stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
 846
 847         if (nbd_write(client->ioc, buf, 18, errp) < 0) {
 848             error_prepend(errp, "write failed: ");
 849             return -EINVAL;
 850         }
 851         ret = nbd_negotiate_options(client, myflags, errp);
 852         if (ret != 0) {
 853             if (ret < 0) {
 854                 error_prepend(errp, "option negotiation failed: ");
 855             }
 856             return ret;
 857         }
 858     }
 859
 860     trace_nbd_negotiate_success();
 861
 862     return 0;
 863 }
 864
 865 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
 866                                Error **errp)
 867 {
 868     uint8_t buf[NBD_REQUEST_SIZE];
 869     uint32_t magic;
 870     int ret;
 871
 872     ret = nbd_read(ioc, buf, sizeof(buf), errp);
 873     if (ret < 0) {
 874         return ret;
 875     }
 876
 877     /* Request
 878        [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
 879        [ 4 ..  5]   flags   (NBD_CMD_FLAG_FUA, ...)
 880        [ 6 ..  7]   type    (NBD_CMD_READ, ...)
 881        [ 8 .. 15]   handle
 882        [16 .. 23]   from
 883        [24 .. 27]   len
 884      */
 885
 886     magic = ldl_be_p(buf);
 887     request->flags  = lduw_be_p(buf + 4);
 888     request->type   = lduw_be_p(buf + 6);
 889     request->handle = ldq_be_p(buf + 8);
 890     request->from   = ldq_be_p(buf + 16);
 891     request->len    = ldl_be_p(buf + 24);
 892
 893     trace_nbd_receive_request(magic, request->flags, request->type,
 894                               request->from, request->len);
 895
 896     if (magic != NBD_REQUEST_MAGIC) {
 897         error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
 898         return -EINVAL;
 899     }
 900     return 0;
 901 }
 902
 903 static int nbd_send_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
 904 {
 905     uint8_t buf[NBD_REPLY_SIZE];
 906
 907     reply->error = system_errno_to_nbd_errno(reply->error);
 908
 909     trace_nbd_send_reply(reply->error, reply->handle);
 910
 911     /* Reply
 912        [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 913        [ 4 ..  7]    error   (0 == no error)
 914        [ 7 .. 15]    handle
 915      */
 916     stl_be_p(buf, NBD_REPLY_MAGIC);
 917     stl_be_p(buf + 4, reply->error);
 918     stq_be_p(buf + 8, reply->handle);
 919
 920     return nbd_write(ioc, buf, sizeof(buf), errp);
 921 }
 922
 923 #define MAX_NBD_REQUESTS 16
 924
 925 void nbd_client_get(NBDClient *client)
 926 {
 927     client->refcount++;
 928 }
 929
 930 void nbd_client_put(NBDClient *client)
 931 {
 932     if (--client->refcount == 0) {
 933         /* The last reference should be dropped by client->close,
 934          * which is called by client_close.
 935          */
 936         assert(client->closing);
 937
 938         qio_channel_detach_aio_context(client->ioc);
 939         object_unref(OBJECT(client->sioc));
 940         object_unref(OBJECT(client->ioc));
 941         if (client->tlscreds) {
 942             object_unref(OBJECT(client->tlscreds));
 943         }
 944         g_free(client->tlsaclname);
 945         if (client->exp) {
 946             QTAILQ_REMOVE(&client->exp->clients, client, next);
 947             nbd_export_put(client->exp);
 948         }
 949         g_free(client);
 950     }
 951 }
 952
 953 static void client_close(NBDClient *client, bool negotiated)
 954 {
 955     if (client->closing) {
 956         return;
 957     }
 958
 959     client->closing = true;
 960
 961     /* Force requests to finish.  They will drop their own references,
 962      * then we'll close the socket and free the NBDClient.
 963      */
 964     qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
 965                          NULL);
 966
 967     /* Also tell the client, so that they release their reference.  */
 968     if (client->close_fn) {
 969         client->close_fn(client, negotiated);
 970     }
 971 }
 972
 973 static NBDRequestData *nbd_request_get(NBDClient *client)
 974 {
 975     NBDRequestData *req;
 976
 977     assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
 978     client->nb_requests++;
 979
 980     req = g_new0(NBDRequestData, 1);
 981     nbd_client_get(client);
 982     req->client = client;
 983     return req;
 984 }
 985
 986 static void nbd_request_put(NBDRequestData *req)
 987 {
 988     NBDClient *client = req->client;
 989
 990     if (req->data) {
 991         qemu_vfree(req->data);
 992     }
 993     g_free(req);
 994
 995     client->nb_requests--;
 996     nbd_client_receive_next_request(client);
 997
 998     nbd_client_put(client);
 999 }
1000
1001 static void blk_aio_attached(AioContext *ctx, void *opaque)
1002 {
1003     NBDExport *exp = opaque;
1004     NBDClient *client;
1005
1006     trace_nbd_blk_aio_attached(exp->name, ctx);
1007
1008     exp->ctx = ctx;
1009
1010     QTAILQ_FOREACH(client, &exp->clients, next) {
1011         qio_channel_attach_aio_context(client->ioc, ctx);
1012         if (client->recv_coroutine) {
1013             aio_co_schedule(ctx, client->recv_coroutine);
1014         }
1015         if (client->send_coroutine) {
1016             aio_co_schedule(ctx, client->send_coroutine);
1017         }
1018     }
1019 }
1020
1021 static void blk_aio_detach(void *opaque)
1022 {
1023     NBDExport *exp = opaque;
1024     NBDClient *client;
1025
1026     trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1027
1028     QTAILQ_FOREACH(client, &exp->clients, next) {
1029         qio_channel_detach_aio_context(client->ioc);
1030     }
1031
1032     exp->ctx = NULL;
1033 }
1034
1035 static void nbd_eject_notifier(Notifier *n, void *data)
1036 {
1037     NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1038     nbd_export_close(exp);
1039 }
1040
1041 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
1042                           uint16_t nbdflags, void (*close)(NBDExport *),
1043                           bool writethrough, BlockBackend *on_eject_blk,
1044                           Error **errp)
1045 {
1046     BlockBackend *blk;
1047     NBDExport *exp = g_malloc0(sizeof(NBDExport));
1048     uint64_t perm;
1049     int ret;
1050
1051     /* Don't allow resize while the NBD server is running, otherwise we don't
1052      * care what happens with the node. */
1053     perm = BLK_PERM_CONSISTENT_READ;
1054     if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1055         perm |= BLK_PERM_WRITE;
1056     }
1057     blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1058                         BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1059     ret = blk_insert_bs(blk, bs, errp);
1060     if (ret < 0) {
1061         goto fail;
1062     }
1063     blk_set_enable_write_cache(blk, !writethrough);
1064
1065     exp->refcount = 1;
1066     QTAILQ_INIT(&exp->clients);
1067     exp->blk = blk;
1068     exp->dev_offset = dev_offset;
1069     exp->nbdflags = nbdflags;
1070     exp->size = size < 0 ? blk_getlength(blk) : size;
1071     if (exp->size < 0) {
1072         error_setg_errno(errp, -exp->size,
1073                          "Failed to determine the NBD export's length");
1074         goto fail;
1075     }
1076     exp->size -= exp->size % BDRV_SECTOR_SIZE;
1077
1078     exp->close = close;
1079     exp->ctx = blk_get_aio_context(blk);
1080     blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1081
1082     if (on_eject_blk) {
1083         blk_ref(on_eject_blk);
1084         exp->eject_notifier_blk = on_eject_blk;
1085         exp->eject_notifier.notify = nbd_eject_notifier;
1086         blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1087     }
1088
1089     /*
1090      * NBD exports are used for non-shared storage migration.  Make sure
1091      * that BDRV_O_INACTIVE is cleared and the image is ready for write
1092      * access since the export could be available before migration handover.
1093      */
1094     aio_context_acquire(exp->ctx);
1095     blk_invalidate_cache(blk, NULL);
1096     aio_context_release(exp->ctx);
1097     return exp;
1098
1099 fail:
1100     blk_unref(blk);
1101     g_free(exp);
1102     return NULL;
1103 }
1104
1105 NBDExport *nbd_export_find(const char *name)
1106 {
1107     NBDExport *exp;
1108     QTAILQ_FOREACH(exp, &exports, next) {
1109         if (strcmp(name, exp->name) == 0) {
1110             return exp;
1111         }
1112     }
1113
1114     return NULL;
1115 }
1116
1117 void nbd_export_set_name(NBDExport *exp, const char *name)
1118 {
1119     if (exp->name == name) {
1120         return;
1121     }
1122
1123     nbd_export_get(exp);
1124     if (exp->name != NULL) {
1125         g_free(exp->name);
1126         exp->name = NULL;
1127         QTAILQ_REMOVE(&exports, exp, next);
1128         nbd_export_put(exp);
1129     }
1130     if (name != NULL) {
1131         nbd_export_get(exp);
1132         exp->name = g_strdup(name);
1133         QTAILQ_INSERT_TAIL(&exports, exp, next);
1134     }
1135     nbd_export_put(exp);
1136 }
1137
1138 void nbd_export_set_description(NBDExport *exp, const char *description)
1139 {
1140     g_free(exp->description);
1141     exp->description = g_strdup(description);
1142 }
1143
1144 void nbd_export_close(NBDExport *exp)
1145 {
1146     NBDClient *client, *next;
1147
1148     nbd_export_get(exp);
1149     QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1150         client_close(client, true);
1151     }
1152     nbd_export_set_name(exp, NULL);
1153     nbd_export_set_description(exp, NULL);
1154     nbd_export_put(exp);
1155 }
1156
1157 void nbd_export_get(NBDExport *exp)
1158 {
1159     assert(exp->refcount > 0);
1160     exp->refcount++;
1161 }
1162
1163 void nbd_export_put(NBDExport *exp)
1164 {
1165     assert(exp->refcount > 0);
1166     if (exp->refcount == 1) {
1167         nbd_export_close(exp);
1168     }
1169
1170     if (--exp->refcount == 0) {
1171         assert(exp->name == NULL);
1172         assert(exp->description == NULL);
1173
1174         if (exp->close) {
1175             exp->close(exp);
1176         }
1177
1178         if (exp->blk) {
1179             if (exp->eject_notifier_blk) {
1180                 notifier_remove(&exp->eject_notifier);
1181                 blk_unref(exp->eject_notifier_blk);
1182             }
1183             blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1184                                             blk_aio_detach, exp);
1185             blk_unref(exp->blk);
1186             exp->blk = NULL;
1187         }
1188
1189         g_free(exp);
1190     }
1191 }
1192
1193 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1194 {
1195     return exp->blk;
1196 }
1197
1198 void nbd_export_close_all(void)
1199 {
1200     NBDExport *exp, *next;
1201
1202     QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1203         nbd_export_close(exp);
1204     }
1205 }
1206
1207 static int nbd_co_send_reply(NBDRequestData *req, NBDReply *reply, int len,
1208                              Error **errp)
1209 {
1210     NBDClient *client = req->client;
1211     int ret;
1212
1213     g_assert(qemu_in_coroutine());
1214
1215     trace_nbd_co_send_reply(reply->handle, reply->error, len);
1216
1217     qemu_co_mutex_lock(&client->send_lock);
1218     client->send_coroutine = qemu_coroutine_self();
1219
1220     if (!len) {
1221         ret = nbd_send_reply(client->ioc, reply, errp);
1222     } else {
1223         qio_channel_set_cork(client->ioc, true);
1224         ret = nbd_send_reply(client->ioc, reply, errp);
1225         if (ret == 0) {
1226             ret = nbd_write(client->ioc, req->data, len, errp);
1227             if (ret < 0) {
1228                 ret = -EIO;
1229             }
1230         }
1231         qio_channel_set_cork(client->ioc, false);
1232     }
1233
1234     client->send_coroutine = NULL;
1235     qemu_co_mutex_unlock(&client->send_lock);
1236     return ret;
1237 }
1238
1239 /* nbd_co_receive_request
1240  * Collect a client request. Return 0 if request looks valid, -EIO to drop
1241  * connection right away, and any other negative value to report an error to
1242  * the client (although the caller may still need to disconnect after reporting
1243  * the error).
1244  */
1245 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
1246                                   Error **errp)
1247 {
1248     NBDClient *client = req->client;
1249
1250     g_assert(qemu_in_coroutine());
1251     assert(client->recv_coroutine == qemu_coroutine_self());
1252     if (nbd_receive_request(client->ioc, request, errp) < 0) {
1253         return -EIO;
1254     }
1255
1256     trace_nbd_co_receive_request_decode_type(request->handle, request->type,
1257                                              nbd_cmd_lookup(request->type));
1258
1259     if (request->type != NBD_CMD_WRITE) {
1260         /* No payload, we are ready to read the next request.  */
1261         req->complete = true;
1262     }
1263
1264     if (request->type == NBD_CMD_DISC) {
1265         /* Special case: we're going to disconnect without a reply,
1266          * whether or not flags, from, or len are bogus */
1267         return -EIO;
1268     }
1269
1270     /* Check for sanity in the parameters, part 1.  Defer as many
1271      * checks as possible until after reading any NBD_CMD_WRITE
1272      * payload, so we can try and keep the connection alive.  */
1273     if ((request->from + request->len) < request->from) {
1274         error_setg(errp,
1275                    "integer overflow detected, you're probably being attacked");
1276         return -EINVAL;
1277     }
1278
1279     if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) {
1280         if (request->len > NBD_MAX_BUFFER_SIZE) {
1281             error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1282                        request->len, NBD_MAX_BUFFER_SIZE);
1283             return -EINVAL;
1284         }
1285
1286         req->data = blk_try_blockalign(client->exp->blk, request->len);
1287         if (req->data == NULL) {
1288             error_setg(errp, "No memory");
1289             return -ENOMEM;
1290         }
1291     }
1292     if (request->type == NBD_CMD_WRITE) {
1293         if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
1294             error_prepend(errp, "reading from socket failed: ");
1295             return -EIO;
1296         }
1297         req->complete = true;
1298
1299         trace_nbd_co_receive_request_payload_received(request->handle,
1300                                                       request->len);
1301     }
1302
1303     /* Sanity checks, part 2. */
1304     if (request->from + request->len > client->exp->size) {
1305         error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
1306                    ", Size: %" PRIu64, request->from, request->len,
1307                    (uint64_t)client->exp->size);
1308         return request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
1309     }
1310     if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
1311         error_setg(errp, "unsupported flags (got 0x%x)", request->flags);
1312         return -EINVAL;
1313     }
1314     if (request->type != NBD_CMD_WRITE_ZEROES &&
1315         (request->flags & NBD_CMD_FLAG_NO_HOLE)) {
1316         error_setg(errp, "unexpected flags (got 0x%x)", request->flags);
1317         return -EINVAL;
1318     }
1319
1320     return 0;
1321 }
1322
1323 /* Owns a reference to the NBDClient passed as opaque.  */
1324 static coroutine_fn void nbd_trip(void *opaque)
1325 {
1326     NBDClient *client = opaque;
1327     NBDExport *exp = client->exp;
1328     NBDRequestData *req;
1329     NBDRequest request = { 0 };    /* GCC thinks it can be used uninitialized */
1330     NBDReply reply;
1331     int ret;
1332     int flags;
1333     int reply_data_len = 0;
1334     Error *local_err = NULL;
1335
1336     trace_nbd_trip();
1337     if (client->closing) {
1338         nbd_client_put(client);
1339         return;
1340     }
1341
1342     req = nbd_request_get(client);
1343     ret = nbd_co_receive_request(req, &request, &local_err);
1344     client->recv_coroutine = NULL;
1345     nbd_client_receive_next_request(client);
1346     if (ret == -EIO) {
1347         goto disconnect;
1348     }
1349
1350     reply.handle = request.handle;
1351     reply.error = 0;
1352
1353     if (ret < 0) {
1354         reply.error = -ret;
1355         goto reply;
1356     }
1357
1358     if (client->closing) {
1359         /*
1360          * The client may be closed when we are blocked in
1361          * nbd_co_receive_request()
1362          */
1363         goto done;
1364     }
1365
1366     switch (request.type) {
1367     case NBD_CMD_READ:
1368         /* XXX: NBD Protocol only documents use of FUA with WRITE */
1369         if (request.flags & NBD_CMD_FLAG_FUA) {
1370             ret = blk_co_flush(exp->blk);
1371             if (ret < 0) {
1372                 error_setg_errno(&local_err, -ret, "flush failed");
1373                 reply.error = -ret;
1374                 break;
1375             }
1376         }
1377
1378         ret = blk_pread(exp->blk, request.from + exp->dev_offset,
1379                         req->data, request.len);
1380         if (ret < 0) {
1381             error_setg_errno(&local_err, -ret, "reading from file failed");
1382             reply.error = -ret;
1383             break;
1384         }
1385
1386         reply_data_len = request.len;
1387
1388         break;
1389     case NBD_CMD_WRITE:
1390         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1391             reply.error = EROFS;
1392             break;
1393         }
1394
1395         flags = 0;
1396         if (request.flags & NBD_CMD_FLAG_FUA) {
1397             flags |= BDRV_REQ_FUA;
1398         }
1399         ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
1400                          req->data, request.len, flags);
1401         if (ret < 0) {
1402             error_setg_errno(&local_err, -ret, "writing to file failed");
1403             reply.error = -ret;
1404         }
1405
1406         break;
1407     case NBD_CMD_WRITE_ZEROES:
1408         if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1409             error_setg(&local_err, "Server is read-only, return error");
1410             reply.error = EROFS;
1411             break;
1412         }
1413
1414         flags = 0;
1415         if (request.flags & NBD_CMD_FLAG_FUA) {
1416             flags |= BDRV_REQ_FUA;
1417         }
1418         if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) {
1419             flags |= BDRV_REQ_MAY_UNMAP;
1420         }
1421         ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset,
1422                                 request.len, flags);
1423         if (ret < 0) {
1424             error_setg_errno(&local_err, -ret, "writing to file failed");
1425             reply.error = -ret;
1426         }
1427
1428         break;
1429     case NBD_CMD_DISC:
1430         /* unreachable, thanks to special case in nbd_co_receive_request() */
1431         abort();
1432
1433     case NBD_CMD_FLUSH:
1434         ret = blk_co_flush(exp->blk);
1435         if (ret < 0) {
1436             error_setg_errno(&local_err, -ret, "flush failed");
1437             reply.error = -ret;
1438         }
1439
1440         break;
1441     case NBD_CMD_TRIM:
1442         ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset,
1443                               request.len);
1444         if (ret < 0) {
1445             error_setg_errno(&local_err, -ret, "discard failed");
1446             reply.error = -ret;
1447         }
1448
1449         break;
1450     default:
1451         error_setg(&local_err, "invalid request type (%" PRIu32 ") received",
1452                    request.type);
1453         reply.error = EINVAL;
1454     }
1455
1456 reply:
1457     if (local_err) {
1458         /* If we are here local_err is not fatal error, already stored in
1459          * reply.error */
1460         error_report_err(local_err);
1461         local_err = NULL;
1462     }
1463
1464     if (nbd_co_send_reply(req, &reply, reply_data_len, &local_err) < 0) {
1465         error_prepend(&local_err, "Failed to send reply: ");
1466         goto disconnect;
1467     }
1468
1469     /* We must disconnect after NBD_CMD_WRITE if we did not
1470      * read the payload.
1471      */
1472     if (!req->complete) {
1473         error_setg(&local_err, "Request handling failed in intermediate state");
1474         goto disconnect;
1475     }
1476
1477 done:
1478     nbd_request_put(req);
1479     nbd_client_put(client);
1480     return;
1481
1482 disconnect:
1483     if (local_err) {
1484         error_reportf_err(local_err, "Disconnect client, due to: ");
1485     }
1486     nbd_request_put(req);
1487     client_close(client, true);
1488     nbd_client_put(client);
1489 }
1490
1491 static void nbd_client_receive_next_request(NBDClient *client)
1492 {
1493     if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
1494         nbd_client_get(client);
1495         client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
1496         aio_co_schedule(client->exp->ctx, client->recv_coroutine);
1497     }
1498 }
1499
1500 static coroutine_fn void nbd_co_client_start(void *opaque)
1501 {
1502     NBDClient *client = opaque;
1503     NBDExport *exp = client->exp;
1504     Error *local_err = NULL;
1505
1506     if (exp) {
1507         nbd_export_get(exp);
1508         QTAILQ_INSERT_TAIL(&exp->clients, client, next);
1509     }
1510     qemu_co_mutex_init(&client->send_lock);
1511
1512     if (nbd_negotiate(client, &local_err)) {
1513         if (local_err) {
1514             error_report_err(local_err);
1515         }
1516         client_close(client, false);
1517         return;
1518     }
1519
1520     nbd_client_receive_next_request(client);
1521 }
1522
1523 /*
1524  * Create a new client listener on the given export @exp, using the
1525  * given channel @sioc.  Begin servicing it in a coroutine.  When the
1526  * connection closes, call @close_fn with an indication of whether the
1527  * client completed negotiation.
1528  */
1529 void nbd_client_new(NBDExport *exp,
1530                     QIOChannelSocket *sioc,
1531                     QCryptoTLSCreds *tlscreds,
1532                     const char *tlsaclname,
1533                     void (*close_fn)(NBDClient *, bool))
1534 {
1535     NBDClient *client;
1536     Coroutine *co;
1537
1538     client = g_malloc0(sizeof(NBDClient));
1539     client->refcount = 1;
1540     client->exp = exp;
1541     client->tlscreds = tlscreds;
1542     if (tlscreds) {
1543         object_ref(OBJECT(client->tlscreds));
1544     }
1545     client->tlsaclname = g_strdup(tlsaclname);
1546     client->sioc = sioc;
1547     object_ref(OBJECT(client->sioc));
1548     client->ioc = QIO_CHANNEL(sioc);
1549     object_ref(OBJECT(client->ioc));
1550     client->close_fn = close_fn;
1551
1552     co = qemu_coroutine_create(nbd_co_client_start, client);
1553     qemu_coroutine_enter(co);
1554 }