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 EOVERFLOW: 44 return NBD_EOVERFLOW; 45 case ESHUTDOWN: 46 return NBD_ESHUTDOWN; 47 case EINVAL: 48 default: 49 return NBD_EINVAL; 50 } 51 } 52 53 /* Definitions for opaque data types */ 54 55 typedef struct NBDRequestData NBDRequestData; 56 57 struct NBDRequestData { 58 QSIMPLEQ_ENTRY(NBDRequestData) entry; 59 NBDClient *client; 60 uint8_t *data; 61 bool complete; 62 }; 63 64 struct NBDExport { 65 int refcount; 66 void (*close)(NBDExport *exp); 67 68 BlockBackend *blk; 69 char *name; 70 char *description; 71 off_t dev_offset; 72 off_t size; 73 uint16_t nbdflags; 74 QTAILQ_HEAD(, NBDClient) clients; 75 QTAILQ_ENTRY(NBDExport) next; 76 77 AioContext *ctx; 78 79 BlockBackend *eject_notifier_blk; 80 Notifier eject_notifier; 81 }; 82 83 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 84 85 struct NBDClient { 86 int refcount; 87 void (*close_fn)(NBDClient *client, bool negotiated); 88 89 NBDExport *exp; 90 QCryptoTLSCreds *tlscreds; 91 char *tlsaclname; 92 QIOChannelSocket *sioc; /* The underlying data channel */ 93 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 94 95 Coroutine *recv_coroutine; 96 97 CoMutex send_lock; 98 Coroutine *send_coroutine; 99 100 QTAILQ_ENTRY(NBDClient) next; 101 int nb_requests; 102 bool closing; 103 104 bool structured_reply; 105 }; 106 107 /* That's all folks */ 108 109 static void nbd_client_receive_next_request(NBDClient *client); 110 111 /* Basic flow for negotiation 112 113 Server Client 114 Negotiate 115 116 or 117 118 Server Client 119 Negotiate #1 120 Option 121 Negotiate #2 122 123 ---- 124 125 followed by 126 127 Server Client 128 Request 129 Response 130 Request 131 Response 132 ... 133 ... 134 Request (type == 2) 135 136 */ 137 138 /* Send a reply header, including length, but no payload. 139 * Return -errno on error, 0 on success. */ 140 static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type, 141 uint32_t opt, uint32_t len, Error **errp) 142 { 143 uint64_t magic; 144 145 trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt), 146 type, nbd_rep_lookup(type), len); 147 148 assert(len < NBD_MAX_BUFFER_SIZE); 149 magic = cpu_to_be64(NBD_REP_MAGIC); 150 if (nbd_write(ioc, &magic, sizeof(magic), errp) < 0) { 151 error_prepend(errp, "write failed (rep magic): "); 152 return -EINVAL; 153 } 154 155 opt = cpu_to_be32(opt); 156 if (nbd_write(ioc, &opt, sizeof(opt), errp) < 0) { 157 error_prepend(errp, "write failed (rep opt): "); 158 return -EINVAL; 159 } 160 161 type = cpu_to_be32(type); 162 if (nbd_write(ioc, &type, sizeof(type), errp) < 0) { 163 error_prepend(errp, "write failed (rep type): "); 164 return -EINVAL; 165 } 166 167 len = cpu_to_be32(len); 168 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 169 error_prepend(errp, "write failed (rep data length): "); 170 return -EINVAL; 171 } 172 return 0; 173 } 174 175 /* Send a reply header with default 0 length. 176 * Return -errno on error, 0 on success. */ 177 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt, 178 Error **errp) 179 { 180 return nbd_negotiate_send_rep_len(ioc, type, opt, 0, errp); 181 } 182 183 /* Send an error reply. 184 * Return -errno on error, 0 on success. */ 185 static int GCC_FMT_ATTR(5, 6) 186 nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type, 187 uint32_t opt, Error **errp, const char *fmt, ...) 188 { 189 va_list va; 190 char *msg; 191 int ret; 192 size_t len; 193 194 va_start(va, fmt); 195 msg = g_strdup_vprintf(fmt, va); 196 va_end(va); 197 len = strlen(msg); 198 assert(len < 4096); 199 trace_nbd_negotiate_send_rep_err(msg); 200 ret = nbd_negotiate_send_rep_len(ioc, type, opt, len, errp); 201 if (ret < 0) { 202 goto out; 203 } 204 if (nbd_write(ioc, msg, len, errp) < 0) { 205 error_prepend(errp, "write failed (error message): "); 206 ret = -EIO; 207 } else { 208 ret = 0; 209 } 210 211 out: 212 g_free(msg); 213 return ret; 214 } 215 216 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 217 * Return -errno on error, 0 on success. */ 218 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp, 219 Error **errp) 220 { 221 size_t name_len, desc_len; 222 uint32_t len; 223 const char *name = exp->name ? exp->name : ""; 224 const char *desc = exp->description ? exp->description : ""; 225 int ret; 226 227 trace_nbd_negotiate_send_rep_list(name, desc); 228 name_len = strlen(name); 229 desc_len = strlen(desc); 230 len = name_len + desc_len + sizeof(len); 231 ret = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len, 232 errp); 233 if (ret < 0) { 234 return ret; 235 } 236 237 len = cpu_to_be32(name_len); 238 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 239 error_prepend(errp, "write failed (name length): "); 240 return -EINVAL; 241 } 242 243 if (nbd_write(ioc, name, name_len, errp) < 0) { 244 error_prepend(errp, "write failed (name buffer): "); 245 return -EINVAL; 246 } 247 248 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 249 error_prepend(errp, "write failed (description buffer): "); 250 return -EINVAL; 251 } 252 253 return 0; 254 } 255 256 /* Process the NBD_OPT_LIST command, with a potential series of replies. 257 * Return -errno on error, 0 on success. */ 258 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 259 { 260 NBDExport *exp; 261 262 /* For each export, send a NBD_REP_SERVER reply. */ 263 QTAILQ_FOREACH(exp, &exports, next) { 264 if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) { 265 return -EINVAL; 266 } 267 } 268 /* Finish with a NBD_REP_ACK. */ 269 return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST, errp); 270 } 271 272 /* Send a reply to NBD_OPT_EXPORT_NAME. 273 * Return -errno on error, 0 on success. */ 274 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length, 275 uint16_t myflags, bool no_zeroes, 276 Error **errp) 277 { 278 char name[NBD_MAX_NAME_SIZE + 1]; 279 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 280 size_t len; 281 int ret; 282 283 /* Client sends: 284 [20 .. xx] export name (length bytes) 285 Server replies: 286 [ 0 .. 7] size 287 [ 8 .. 9] export flags 288 [10 .. 133] reserved (0) [unless no_zeroes] 289 */ 290 trace_nbd_negotiate_handle_export_name(); 291 if (length >= sizeof(name)) { 292 error_setg(errp, "Bad length received"); 293 return -EINVAL; 294 } 295 if (nbd_read(client->ioc, name, length, errp) < 0) { 296 error_prepend(errp, "read failed: "); 297 return -EINVAL; 298 } 299 name[length] = '\0'; 300 301 trace_nbd_negotiate_handle_export_name_request(name); 302 303 client->exp = nbd_export_find(name); 304 if (!client->exp) { 305 error_setg(errp, "export not found"); 306 return -EINVAL; 307 } 308 309 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 310 client->exp->nbdflags | myflags); 311 stq_be_p(buf, client->exp->size); 312 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 313 len = no_zeroes ? 10 : sizeof(buf); 314 ret = nbd_write(client->ioc, buf, len, errp); 315 if (ret < 0) { 316 error_prepend(errp, "write failed: "); 317 return ret; 318 } 319 320 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 321 nbd_export_get(client->exp); 322 323 return 0; 324 } 325 326 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 327 * The buffer does NOT include the info type prefix. 328 * Return -errno on error, 0 if ready to send more. */ 329 static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt, 330 uint16_t info, uint32_t length, void *buf, 331 Error **errp) 332 { 333 int rc; 334 335 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 336 rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt, 337 sizeof(info) + length, errp); 338 if (rc < 0) { 339 return rc; 340 } 341 cpu_to_be16s(&info); 342 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 343 return -EIO; 344 } 345 if (nbd_write(client->ioc, buf, length, errp) < 0) { 346 return -EIO; 347 } 348 return 0; 349 } 350 351 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 352 * Return -errno on error, 0 if ready for next option, and 1 to move 353 * into transmission phase. */ 354 static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length, 355 uint32_t opt, uint16_t myflags, 356 Error **errp) 357 { 358 int rc; 359 char name[NBD_MAX_NAME_SIZE + 1]; 360 NBDExport *exp; 361 uint16_t requests; 362 uint16_t request; 363 uint32_t namelen; 364 bool sendname = false; 365 bool blocksize = false; 366 uint32_t sizes[3]; 367 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 368 const char *msg; 369 370 /* Client sends: 371 4 bytes: L, name length (can be 0) 372 L bytes: export name 373 2 bytes: N, number of requests (can be 0) 374 N * 2 bytes: N requests 375 */ 376 if (length < sizeof(namelen) + sizeof(requests)) { 377 msg = "overall request too short"; 378 goto invalid; 379 } 380 if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) { 381 return -EIO; 382 } 383 be32_to_cpus(&namelen); 384 length -= sizeof(namelen); 385 if (namelen > length - sizeof(requests) || (length - namelen) % 2) { 386 msg = "name length is incorrect"; 387 goto invalid; 388 } 389 if (nbd_read(client->ioc, name, namelen, errp) < 0) { 390 return -EIO; 391 } 392 name[namelen] = '\0'; 393 length -= namelen; 394 trace_nbd_negotiate_handle_export_name_request(name); 395 396 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) { 397 return -EIO; 398 } 399 be16_to_cpus(&requests); 400 length -= sizeof(requests); 401 trace_nbd_negotiate_handle_info_requests(requests); 402 if (requests != length / sizeof(request)) { 403 msg = "incorrect number of requests for overall length"; 404 goto invalid; 405 } 406 while (requests--) { 407 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) { 408 return -EIO; 409 } 410 be16_to_cpus(&request); 411 length -= sizeof(request); 412 trace_nbd_negotiate_handle_info_request(request, 413 nbd_info_lookup(request)); 414 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 415 * everything else is either a request we don't know or 416 * something we send regardless of request */ 417 switch (request) { 418 case NBD_INFO_NAME: 419 sendname = true; 420 break; 421 case NBD_INFO_BLOCK_SIZE: 422 blocksize = true; 423 break; 424 } 425 } 426 assert(length == 0); 427 428 exp = nbd_export_find(name); 429 if (!exp) { 430 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN, 431 opt, errp, "export '%s' not present", 432 name); 433 } 434 435 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 436 if (sendname) { 437 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, namelen, name, 438 errp); 439 if (rc < 0) { 440 return rc; 441 } 442 } 443 444 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 445 * client request */ 446 if (exp->description) { 447 size_t len = strlen(exp->description); 448 449 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION, 450 len, exp->description, errp); 451 if (rc < 0) { 452 return rc; 453 } 454 } 455 456 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 457 * according to whether the client requested it, and according to 458 * whether this is OPT_INFO or OPT_GO. */ 459 /* minimum - 1 for back-compat, or 512 if client is new enough. 460 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 461 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 462 /* preferred - Hard-code to 4096 for now. 463 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 464 sizes[1] = 4096; 465 /* maximum - At most 32M, but smaller as appropriate. */ 466 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 467 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 468 cpu_to_be32s(&sizes[0]); 469 cpu_to_be32s(&sizes[1]); 470 cpu_to_be32s(&sizes[2]); 471 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE, 472 sizeof(sizes), sizes, errp); 473 if (rc < 0) { 474 return rc; 475 } 476 477 /* Send NBD_INFO_EXPORT always */ 478 trace_nbd_negotiate_new_style_size_flags(exp->size, 479 exp->nbdflags | myflags); 480 stq_be_p(buf, exp->size); 481 stw_be_p(buf + 8, exp->nbdflags | myflags); 482 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT, 483 sizeof(buf), buf, errp); 484 if (rc < 0) { 485 return rc; 486 } 487 488 /* If the client is just asking for NBD_OPT_INFO, but forgot to 489 * request block sizes, return an error. 490 * TODO: consult blk_bs(blk)->request_align, and only error if it 491 * is not 1? */ 492 if (opt == NBD_OPT_INFO && !blocksize) { 493 return nbd_negotiate_send_rep_err(client->ioc, 494 NBD_REP_ERR_BLOCK_SIZE_REQD, opt, 495 errp, 496 "request NBD_INFO_BLOCK_SIZE to " 497 "use this export"); 498 } 499 500 /* Final reply */ 501 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp); 502 if (rc < 0) { 503 return rc; 504 } 505 506 if (opt == NBD_OPT_GO) { 507 client->exp = exp; 508 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 509 nbd_export_get(client->exp); 510 rc = 1; 511 } 512 return rc; 513 514 invalid: 515 if (nbd_drop(client->ioc, length, errp) < 0) { 516 return -EIO; 517 } 518 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt, 519 errp, "%s", msg); 520 } 521 522 523 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 524 * new channel for all further (now-encrypted) communication. */ 525 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 526 Error **errp) 527 { 528 QIOChannel *ioc; 529 QIOChannelTLS *tioc; 530 struct NBDTLSHandshakeData data = { 0 }; 531 532 trace_nbd_negotiate_handle_starttls(); 533 ioc = client->ioc; 534 535 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 536 NBD_OPT_STARTTLS, errp) < 0) { 537 return NULL; 538 } 539 540 tioc = qio_channel_tls_new_server(ioc, 541 client->tlscreds, 542 client->tlsaclname, 543 errp); 544 if (!tioc) { 545 return NULL; 546 } 547 548 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 549 trace_nbd_negotiate_handle_starttls_handshake(); 550 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 551 qio_channel_tls_handshake(tioc, 552 nbd_tls_handshake, 553 &data, 554 NULL); 555 556 if (!data.complete) { 557 g_main_loop_run(data.loop); 558 } 559 g_main_loop_unref(data.loop); 560 if (data.error) { 561 object_unref(OBJECT(tioc)); 562 error_propagate(errp, data.error); 563 return NULL; 564 } 565 566 return QIO_CHANNEL(tioc); 567 } 568 569 /* nbd_reject_length: Handle any unexpected payload. 570 * @fatal requests that we quit talking to the client, even if we are able 571 * to successfully send an error to the guest. 572 * Return: 573 * -errno transmission error occurred or @fatal was requested, errp is set 574 * 0 error message successfully sent to client, errp is not set 575 */ 576 static int nbd_reject_length(NBDClient *client, uint32_t length, 577 uint32_t option, bool fatal, Error **errp) 578 { 579 int ret; 580 581 assert(length); 582 if (nbd_drop(client->ioc, length, errp) < 0) { 583 return -EIO; 584 } 585 ret = nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, 586 option, errp, 587 "option '%s' should have zero length", 588 nbd_opt_lookup(option)); 589 if (fatal && !ret) { 590 error_setg(errp, "option '%s' should have zero length", 591 nbd_opt_lookup(option)); 592 return -EINVAL; 593 } 594 return ret; 595 } 596 597 /* nbd_negotiate_options 598 * Process all NBD_OPT_* client option commands, during fixed newstyle 599 * negotiation. 600 * Return: 601 * -errno on error, errp is set 602 * 0 on successful negotiation, errp is not set 603 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 604 * errp is not set 605 */ 606 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 607 Error **errp) 608 { 609 uint32_t flags; 610 bool fixedNewstyle = false; 611 bool no_zeroes = false; 612 613 /* Client sends: 614 [ 0 .. 3] client flags 615 616 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 617 [ 0 .. 7] NBD_OPTS_MAGIC 618 [ 8 .. 11] NBD option 619 [12 .. 15] Data length 620 ... Rest of request 621 622 [ 0 .. 7] NBD_OPTS_MAGIC 623 [ 8 .. 11] Second NBD option 624 [12 .. 15] Data length 625 ... Rest of request 626 */ 627 628 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 629 error_prepend(errp, "read failed: "); 630 return -EIO; 631 } 632 be32_to_cpus(&flags); 633 trace_nbd_negotiate_options_flags(flags); 634 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 635 fixedNewstyle = true; 636 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 637 } 638 if (flags & NBD_FLAG_C_NO_ZEROES) { 639 no_zeroes = true; 640 flags &= ~NBD_FLAG_C_NO_ZEROES; 641 } 642 if (flags != 0) { 643 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 644 return -EINVAL; 645 } 646 647 while (1) { 648 int ret; 649 uint32_t option, length; 650 uint64_t magic; 651 652 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 653 error_prepend(errp, "read failed: "); 654 return -EINVAL; 655 } 656 magic = be64_to_cpu(magic); 657 trace_nbd_negotiate_options_check_magic(magic); 658 if (magic != NBD_OPTS_MAGIC) { 659 error_setg(errp, "Bad magic received"); 660 return -EINVAL; 661 } 662 663 if (nbd_read(client->ioc, &option, 664 sizeof(option), errp) < 0) { 665 error_prepend(errp, "read failed: "); 666 return -EINVAL; 667 } 668 option = be32_to_cpu(option); 669 670 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 671 error_prepend(errp, "read failed: "); 672 return -EINVAL; 673 } 674 length = be32_to_cpu(length); 675 676 trace_nbd_negotiate_options_check_option(option, 677 nbd_opt_lookup(option)); 678 if (client->tlscreds && 679 client->ioc == (QIOChannel *)client->sioc) { 680 QIOChannel *tioc; 681 if (!fixedNewstyle) { 682 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 683 return -EINVAL; 684 } 685 switch (option) { 686 case NBD_OPT_STARTTLS: 687 if (length) { 688 /* Unconditionally drop the connection if the client 689 * can't start a TLS negotiation correctly */ 690 return nbd_reject_length(client, length, option, true, 691 errp); 692 } 693 tioc = nbd_negotiate_handle_starttls(client, errp); 694 if (!tioc) { 695 return -EIO; 696 } 697 ret = 0; 698 object_unref(OBJECT(client->ioc)); 699 client->ioc = QIO_CHANNEL(tioc); 700 break; 701 702 case NBD_OPT_EXPORT_NAME: 703 /* No way to return an error to client, so drop connection */ 704 error_setg(errp, "Option 0x%x not permitted before TLS", 705 option); 706 return -EINVAL; 707 708 default: 709 if (nbd_drop(client->ioc, length, errp) < 0) { 710 return -EIO; 711 } 712 ret = nbd_negotiate_send_rep_err(client->ioc, 713 NBD_REP_ERR_TLS_REQD, 714 option, errp, 715 "Option 0x%" PRIx32 716 "not permitted before TLS", 717 option); 718 /* Let the client keep trying, unless they asked to 719 * quit. In this mode, we've already sent an error, so 720 * we can't ack the abort. */ 721 if (option == NBD_OPT_ABORT) { 722 return 1; 723 } 724 break; 725 } 726 } else if (fixedNewstyle) { 727 switch (option) { 728 case NBD_OPT_LIST: 729 if (length) { 730 ret = nbd_reject_length(client, length, option, false, 731 errp); 732 } else { 733 ret = nbd_negotiate_handle_list(client, errp); 734 } 735 break; 736 737 case NBD_OPT_ABORT: 738 /* NBD spec says we must try to reply before 739 * disconnecting, but that we must also tolerate 740 * guests that don't wait for our reply. */ 741 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL); 742 return 1; 743 744 case NBD_OPT_EXPORT_NAME: 745 return nbd_negotiate_handle_export_name(client, length, 746 myflags, no_zeroes, 747 errp); 748 749 case NBD_OPT_INFO: 750 case NBD_OPT_GO: 751 ret = nbd_negotiate_handle_info(client, length, option, 752 myflags, errp); 753 if (ret == 1) { 754 assert(option == NBD_OPT_GO); 755 return 0; 756 } 757 break; 758 759 case NBD_OPT_STARTTLS: 760 if (length) { 761 ret = nbd_reject_length(client, length, option, false, 762 errp); 763 } else if (client->tlscreds) { 764 ret = nbd_negotiate_send_rep_err(client->ioc, 765 NBD_REP_ERR_INVALID, 766 option, errp, 767 "TLS already enabled"); 768 } else { 769 ret = nbd_negotiate_send_rep_err(client->ioc, 770 NBD_REP_ERR_POLICY, 771 option, errp, 772 "TLS not configured"); 773 } 774 break; 775 776 case NBD_OPT_STRUCTURED_REPLY: 777 if (length) { 778 ret = nbd_reject_length(client, length, option, false, 779 errp); 780 } else if (client->structured_reply) { 781 ret = nbd_negotiate_send_rep_err( 782 client->ioc, NBD_REP_ERR_INVALID, option, errp, 783 "structured reply already negotiated"); 784 } else { 785 ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 786 option, errp); 787 client->structured_reply = true; 788 myflags |= NBD_FLAG_SEND_DF; 789 } 790 break; 791 792 default: 793 if (nbd_drop(client->ioc, length, errp) < 0) { 794 return -EIO; 795 } 796 ret = nbd_negotiate_send_rep_err(client->ioc, 797 NBD_REP_ERR_UNSUP, 798 option, errp, 799 "Unsupported option 0x%" 800 PRIx32 " (%s)", option, 801 nbd_opt_lookup(option)); 802 break; 803 } 804 } else { 805 /* 806 * If broken new-style we should drop the connection 807 * for anything except NBD_OPT_EXPORT_NAME 808 */ 809 switch (option) { 810 case NBD_OPT_EXPORT_NAME: 811 return nbd_negotiate_handle_export_name(client, length, 812 myflags, no_zeroes, 813 errp); 814 815 default: 816 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)", 817 option, nbd_opt_lookup(option)); 818 return -EINVAL; 819 } 820 } 821 if (ret < 0) { 822 return ret; 823 } 824 } 825 } 826 827 /* nbd_negotiate 828 * Return: 829 * -errno on error, errp is set 830 * 0 on successful negotiation, errp is not set 831 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 832 * errp is not set 833 */ 834 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 835 { 836 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 837 int ret; 838 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 839 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 840 NBD_FLAG_SEND_WRITE_ZEROES); 841 bool oldStyle; 842 843 /* Old style negotiation header, no room for options 844 [ 0 .. 7] passwd ("NBDMAGIC") 845 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 846 [16 .. 23] size 847 [24 .. 27] export flags (zero-extended) 848 [28 .. 151] reserved (0) 849 850 New style negotiation header, client can send options 851 [ 0 .. 7] passwd ("NBDMAGIC") 852 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 853 [16 .. 17] server flags (0) 854 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 855 */ 856 857 qio_channel_set_blocking(client->ioc, false, NULL); 858 859 trace_nbd_negotiate_begin(); 860 memcpy(buf, "NBDMAGIC", 8); 861 862 oldStyle = client->exp != NULL && !client->tlscreds; 863 if (oldStyle) { 864 trace_nbd_negotiate_old_style(client->exp->size, 865 client->exp->nbdflags | myflags); 866 stq_be_p(buf + 8, NBD_CLIENT_MAGIC); 867 stq_be_p(buf + 16, client->exp->size); 868 stl_be_p(buf + 24, client->exp->nbdflags | myflags); 869 870 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) { 871 error_prepend(errp, "write failed: "); 872 return -EINVAL; 873 } 874 } else { 875 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 876 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 877 878 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 879 error_prepend(errp, "write failed: "); 880 return -EINVAL; 881 } 882 ret = nbd_negotiate_options(client, myflags, errp); 883 if (ret != 0) { 884 if (ret < 0) { 885 error_prepend(errp, "option negotiation failed: "); 886 } 887 return ret; 888 } 889 } 890 891 trace_nbd_negotiate_success(); 892 893 return 0; 894 } 895 896 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 897 Error **errp) 898 { 899 uint8_t buf[NBD_REQUEST_SIZE]; 900 uint32_t magic; 901 int ret; 902 903 ret = nbd_read(ioc, buf, sizeof(buf), errp); 904 if (ret < 0) { 905 return ret; 906 } 907 908 /* Request 909 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 910 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 911 [ 6 .. 7] type (NBD_CMD_READ, ...) 912 [ 8 .. 15] handle 913 [16 .. 23] from 914 [24 .. 27] len 915 */ 916 917 magic = ldl_be_p(buf); 918 request->flags = lduw_be_p(buf + 4); 919 request->type = lduw_be_p(buf + 6); 920 request->handle = ldq_be_p(buf + 8); 921 request->from = ldq_be_p(buf + 16); 922 request->len = ldl_be_p(buf + 24); 923 924 trace_nbd_receive_request(magic, request->flags, request->type, 925 request->from, request->len); 926 927 if (magic != NBD_REQUEST_MAGIC) { 928 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 929 return -EINVAL; 930 } 931 return 0; 932 } 933 934 #define MAX_NBD_REQUESTS 16 935 936 void nbd_client_get(NBDClient *client) 937 { 938 client->refcount++; 939 } 940 941 void nbd_client_put(NBDClient *client) 942 { 943 if (--client->refcount == 0) { 944 /* The last reference should be dropped by client->close, 945 * which is called by client_close. 946 */ 947 assert(client->closing); 948 949 qio_channel_detach_aio_context(client->ioc); 950 object_unref(OBJECT(client->sioc)); 951 object_unref(OBJECT(client->ioc)); 952 if (client->tlscreds) { 953 object_unref(OBJECT(client->tlscreds)); 954 } 955 g_free(client->tlsaclname); 956 if (client->exp) { 957 QTAILQ_REMOVE(&client->exp->clients, client, next); 958 nbd_export_put(client->exp); 959 } 960 g_free(client); 961 } 962 } 963 964 static void client_close(NBDClient *client, bool negotiated) 965 { 966 if (client->closing) { 967 return; 968 } 969 970 client->closing = true; 971 972 /* Force requests to finish. They will drop their own references, 973 * then we'll close the socket and free the NBDClient. 974 */ 975 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 976 NULL); 977 978 /* Also tell the client, so that they release their reference. */ 979 if (client->close_fn) { 980 client->close_fn(client, negotiated); 981 } 982 } 983 984 static NBDRequestData *nbd_request_get(NBDClient *client) 985 { 986 NBDRequestData *req; 987 988 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 989 client->nb_requests++; 990 991 req = g_new0(NBDRequestData, 1); 992 nbd_client_get(client); 993 req->client = client; 994 return req; 995 } 996 997 static void nbd_request_put(NBDRequestData *req) 998 { 999 NBDClient *client = req->client; 1000 1001 if (req->data) { 1002 qemu_vfree(req->data); 1003 } 1004 g_free(req); 1005 1006 client->nb_requests--; 1007 nbd_client_receive_next_request(client); 1008 1009 nbd_client_put(client); 1010 } 1011 1012 static void blk_aio_attached(AioContext *ctx, void *opaque) 1013 { 1014 NBDExport *exp = opaque; 1015 NBDClient *client; 1016 1017 trace_nbd_blk_aio_attached(exp->name, ctx); 1018 1019 exp->ctx = ctx; 1020 1021 QTAILQ_FOREACH(client, &exp->clients, next) { 1022 qio_channel_attach_aio_context(client->ioc, ctx); 1023 if (client->recv_coroutine) { 1024 aio_co_schedule(ctx, client->recv_coroutine); 1025 } 1026 if (client->send_coroutine) { 1027 aio_co_schedule(ctx, client->send_coroutine); 1028 } 1029 } 1030 } 1031 1032 static void blk_aio_detach(void *opaque) 1033 { 1034 NBDExport *exp = opaque; 1035 NBDClient *client; 1036 1037 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1038 1039 QTAILQ_FOREACH(client, &exp->clients, next) { 1040 qio_channel_detach_aio_context(client->ioc); 1041 } 1042 1043 exp->ctx = NULL; 1044 } 1045 1046 static void nbd_eject_notifier(Notifier *n, void *data) 1047 { 1048 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1049 nbd_export_close(exp); 1050 } 1051 1052 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 1053 uint16_t nbdflags, void (*close)(NBDExport *), 1054 bool writethrough, BlockBackend *on_eject_blk, 1055 Error **errp) 1056 { 1057 AioContext *ctx; 1058 BlockBackend *blk; 1059 NBDExport *exp = g_new0(NBDExport, 1); 1060 uint64_t perm; 1061 int ret; 1062 1063 /* 1064 * NBD exports are used for non-shared storage migration. Make sure 1065 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1066 * access since the export could be available before migration handover. 1067 */ 1068 ctx = bdrv_get_aio_context(bs); 1069 aio_context_acquire(ctx); 1070 bdrv_invalidate_cache(bs, NULL); 1071 aio_context_release(ctx); 1072 1073 /* Don't allow resize while the NBD server is running, otherwise we don't 1074 * care what happens with the node. */ 1075 perm = BLK_PERM_CONSISTENT_READ; 1076 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1077 perm |= BLK_PERM_WRITE; 1078 } 1079 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1080 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1081 ret = blk_insert_bs(blk, bs, errp); 1082 if (ret < 0) { 1083 goto fail; 1084 } 1085 blk_set_enable_write_cache(blk, !writethrough); 1086 1087 exp->refcount = 1; 1088 QTAILQ_INIT(&exp->clients); 1089 exp->blk = blk; 1090 exp->dev_offset = dev_offset; 1091 exp->nbdflags = nbdflags; 1092 exp->size = size < 0 ? blk_getlength(blk) : size; 1093 if (exp->size < 0) { 1094 error_setg_errno(errp, -exp->size, 1095 "Failed to determine the NBD export's length"); 1096 goto fail; 1097 } 1098 exp->size -= exp->size % BDRV_SECTOR_SIZE; 1099 1100 exp->close = close; 1101 exp->ctx = blk_get_aio_context(blk); 1102 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1103 1104 if (on_eject_blk) { 1105 blk_ref(on_eject_blk); 1106 exp->eject_notifier_blk = on_eject_blk; 1107 exp->eject_notifier.notify = nbd_eject_notifier; 1108 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1109 } 1110 return exp; 1111 1112 fail: 1113 blk_unref(blk); 1114 g_free(exp); 1115 return NULL; 1116 } 1117 1118 NBDExport *nbd_export_find(const char *name) 1119 { 1120 NBDExport *exp; 1121 QTAILQ_FOREACH(exp, &exports, next) { 1122 if (strcmp(name, exp->name) == 0) { 1123 return exp; 1124 } 1125 } 1126 1127 return NULL; 1128 } 1129 1130 void nbd_export_set_name(NBDExport *exp, const char *name) 1131 { 1132 if (exp->name == name) { 1133 return; 1134 } 1135 1136 nbd_export_get(exp); 1137 if (exp->name != NULL) { 1138 g_free(exp->name); 1139 exp->name = NULL; 1140 QTAILQ_REMOVE(&exports, exp, next); 1141 nbd_export_put(exp); 1142 } 1143 if (name != NULL) { 1144 nbd_export_get(exp); 1145 exp->name = g_strdup(name); 1146 QTAILQ_INSERT_TAIL(&exports, exp, next); 1147 } 1148 nbd_export_put(exp); 1149 } 1150 1151 void nbd_export_set_description(NBDExport *exp, const char *description) 1152 { 1153 g_free(exp->description); 1154 exp->description = g_strdup(description); 1155 } 1156 1157 void nbd_export_close(NBDExport *exp) 1158 { 1159 NBDClient *client, *next; 1160 1161 nbd_export_get(exp); 1162 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1163 client_close(client, true); 1164 } 1165 nbd_export_set_name(exp, NULL); 1166 nbd_export_set_description(exp, NULL); 1167 nbd_export_put(exp); 1168 } 1169 1170 void nbd_export_get(NBDExport *exp) 1171 { 1172 assert(exp->refcount > 0); 1173 exp->refcount++; 1174 } 1175 1176 void nbd_export_put(NBDExport *exp) 1177 { 1178 assert(exp->refcount > 0); 1179 if (exp->refcount == 1) { 1180 nbd_export_close(exp); 1181 } 1182 1183 if (--exp->refcount == 0) { 1184 assert(exp->name == NULL); 1185 assert(exp->description == NULL); 1186 1187 if (exp->close) { 1188 exp->close(exp); 1189 } 1190 1191 if (exp->blk) { 1192 if (exp->eject_notifier_blk) { 1193 notifier_remove(&exp->eject_notifier); 1194 blk_unref(exp->eject_notifier_blk); 1195 } 1196 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1197 blk_aio_detach, exp); 1198 blk_unref(exp->blk); 1199 exp->blk = NULL; 1200 } 1201 1202 g_free(exp); 1203 } 1204 } 1205 1206 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1207 { 1208 return exp->blk; 1209 } 1210 1211 void nbd_export_close_all(void) 1212 { 1213 NBDExport *exp, *next; 1214 1215 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1216 nbd_export_close(exp); 1217 } 1218 } 1219 1220 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1221 unsigned niov, Error **errp) 1222 { 1223 int ret; 1224 1225 g_assert(qemu_in_coroutine()); 1226 qemu_co_mutex_lock(&client->send_lock); 1227 client->send_coroutine = qemu_coroutine_self(); 1228 1229 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1230 1231 client->send_coroutine = NULL; 1232 qemu_co_mutex_unlock(&client->send_lock); 1233 1234 return ret; 1235 } 1236 1237 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1238 uint64_t handle) 1239 { 1240 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1241 stl_be_p(&reply->error, error); 1242 stq_be_p(&reply->handle, handle); 1243 } 1244 1245 static int nbd_co_send_simple_reply(NBDClient *client, 1246 uint64_t handle, 1247 uint32_t error, 1248 void *data, 1249 size_t len, 1250 Error **errp) 1251 { 1252 NBDSimpleReply reply; 1253 int nbd_err = system_errno_to_nbd_errno(error); 1254 struct iovec iov[] = { 1255 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1256 {.iov_base = data, .iov_len = len} 1257 }; 1258 1259 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1260 len); 1261 set_be_simple_reply(&reply, nbd_err, handle); 1262 1263 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1264 } 1265 1266 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1267 uint16_t type, uint64_t handle, uint32_t length) 1268 { 1269 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1270 stw_be_p(&chunk->flags, flags); 1271 stw_be_p(&chunk->type, type); 1272 stq_be_p(&chunk->handle, handle); 1273 stl_be_p(&chunk->length, length); 1274 } 1275 1276 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1277 uint64_t handle, 1278 Error **errp) 1279 { 1280 NBDStructuredReplyChunk chunk; 1281 struct iovec iov[] = { 1282 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1283 }; 1284 1285 trace_nbd_co_send_structured_done(handle); 1286 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1287 1288 return nbd_co_send_iov(client, iov, 1, errp); 1289 } 1290 1291 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1292 uint64_t handle, 1293 uint64_t offset, 1294 void *data, 1295 size_t size, 1296 Error **errp) 1297 { 1298 NBDStructuredReadData chunk; 1299 struct iovec iov[] = { 1300 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1301 {.iov_base = data, .iov_len = size} 1302 }; 1303 1304 assert(size); 1305 trace_nbd_co_send_structured_read(handle, offset, data, size); 1306 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_OFFSET_DATA, 1307 handle, sizeof(chunk) - sizeof(chunk.h) + size); 1308 stq_be_p(&chunk.offset, offset); 1309 1310 return nbd_co_send_iov(client, iov, 2, errp); 1311 } 1312 1313 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1314 uint64_t handle, 1315 uint32_t error, 1316 const char *msg, 1317 Error **errp) 1318 { 1319 NBDStructuredError chunk; 1320 int nbd_err = system_errno_to_nbd_errno(error); 1321 struct iovec iov[] = { 1322 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1323 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1324 }; 1325 1326 assert(nbd_err); 1327 trace_nbd_co_send_structured_error(handle, nbd_err, 1328 nbd_err_lookup(nbd_err), msg ? msg : ""); 1329 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1330 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1331 stl_be_p(&chunk.error, nbd_err); 1332 stw_be_p(&chunk.message_length, iov[1].iov_len); 1333 1334 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1335 } 1336 1337 /* nbd_co_receive_request 1338 * Collect a client request. Return 0 if request looks valid, -EIO to drop 1339 * connection right away, and any other negative value to report an error to 1340 * the client (although the caller may still need to disconnect after reporting 1341 * the error). 1342 */ 1343 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 1344 Error **errp) 1345 { 1346 NBDClient *client = req->client; 1347 int valid_flags; 1348 1349 g_assert(qemu_in_coroutine()); 1350 assert(client->recv_coroutine == qemu_coroutine_self()); 1351 if (nbd_receive_request(client->ioc, request, errp) < 0) { 1352 return -EIO; 1353 } 1354 1355 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 1356 nbd_cmd_lookup(request->type)); 1357 1358 if (request->type != NBD_CMD_WRITE) { 1359 /* No payload, we are ready to read the next request. */ 1360 req->complete = true; 1361 } 1362 1363 if (request->type == NBD_CMD_DISC) { 1364 /* Special case: we're going to disconnect without a reply, 1365 * whether or not flags, from, or len are bogus */ 1366 return -EIO; 1367 } 1368 1369 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { 1370 if (request->len > NBD_MAX_BUFFER_SIZE) { 1371 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1372 request->len, NBD_MAX_BUFFER_SIZE); 1373 return -EINVAL; 1374 } 1375 1376 req->data = blk_try_blockalign(client->exp->blk, request->len); 1377 if (req->data == NULL) { 1378 error_setg(errp, "No memory"); 1379 return -ENOMEM; 1380 } 1381 } 1382 if (request->type == NBD_CMD_WRITE) { 1383 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 1384 error_prepend(errp, "reading from socket failed: "); 1385 return -EIO; 1386 } 1387 req->complete = true; 1388 1389 trace_nbd_co_receive_request_payload_received(request->handle, 1390 request->len); 1391 } 1392 1393 /* Sanity checks. */ 1394 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 1395 (request->type == NBD_CMD_WRITE || 1396 request->type == NBD_CMD_WRITE_ZEROES || 1397 request->type == NBD_CMD_TRIM)) { 1398 error_setg(errp, "Export is read-only"); 1399 return -EROFS; 1400 } 1401 if (request->from > client->exp->size || 1402 request->from + request->len > client->exp->size) { 1403 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 1404 ", Size: %" PRIu64, request->from, request->len, 1405 (uint64_t)client->exp->size); 1406 return (request->type == NBD_CMD_WRITE || 1407 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 1408 } 1409 valid_flags = NBD_CMD_FLAG_FUA; 1410 if (request->type == NBD_CMD_READ && client->structured_reply) { 1411 valid_flags |= NBD_CMD_FLAG_DF; 1412 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 1413 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 1414 } 1415 if (request->flags & ~valid_flags) { 1416 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 1417 nbd_cmd_lookup(request->type), request->flags); 1418 return -EINVAL; 1419 } 1420 1421 return 0; 1422 } 1423 1424 /* Owns a reference to the NBDClient passed as opaque. */ 1425 static coroutine_fn void nbd_trip(void *opaque) 1426 { 1427 NBDClient *client = opaque; 1428 NBDExport *exp = client->exp; 1429 NBDRequestData *req; 1430 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 1431 int ret; 1432 int flags; 1433 int reply_data_len = 0; 1434 Error *local_err = NULL; 1435 char *msg = NULL; 1436 1437 trace_nbd_trip(); 1438 if (client->closing) { 1439 nbd_client_put(client); 1440 return; 1441 } 1442 1443 req = nbd_request_get(client); 1444 ret = nbd_co_receive_request(req, &request, &local_err); 1445 client->recv_coroutine = NULL; 1446 nbd_client_receive_next_request(client); 1447 if (ret == -EIO) { 1448 goto disconnect; 1449 } 1450 1451 if (ret < 0) { 1452 goto reply; 1453 } 1454 1455 if (client->closing) { 1456 /* 1457 * The client may be closed when we are blocked in 1458 * nbd_co_receive_request() 1459 */ 1460 goto done; 1461 } 1462 1463 switch (request.type) { 1464 case NBD_CMD_READ: 1465 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 1466 if (request.flags & NBD_CMD_FLAG_FUA) { 1467 ret = blk_co_flush(exp->blk); 1468 if (ret < 0) { 1469 error_setg_errno(&local_err, -ret, "flush failed"); 1470 break; 1471 } 1472 } 1473 1474 ret = blk_pread(exp->blk, request.from + exp->dev_offset, 1475 req->data, request.len); 1476 if (ret < 0) { 1477 error_setg_errno(&local_err, -ret, "reading from file failed"); 1478 break; 1479 } 1480 1481 reply_data_len = request.len; 1482 1483 break; 1484 case NBD_CMD_WRITE: 1485 flags = 0; 1486 if (request.flags & NBD_CMD_FLAG_FUA) { 1487 flags |= BDRV_REQ_FUA; 1488 } 1489 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset, 1490 req->data, request.len, flags); 1491 if (ret < 0) { 1492 error_setg_errno(&local_err, -ret, "writing to file failed"); 1493 } 1494 1495 break; 1496 case NBD_CMD_WRITE_ZEROES: 1497 flags = 0; 1498 if (request.flags & NBD_CMD_FLAG_FUA) { 1499 flags |= BDRV_REQ_FUA; 1500 } 1501 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) { 1502 flags |= BDRV_REQ_MAY_UNMAP; 1503 } 1504 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset, 1505 request.len, flags); 1506 if (ret < 0) { 1507 error_setg_errno(&local_err, -ret, "writing to file failed"); 1508 } 1509 1510 break; 1511 case NBD_CMD_DISC: 1512 /* unreachable, thanks to special case in nbd_co_receive_request() */ 1513 abort(); 1514 1515 case NBD_CMD_FLUSH: 1516 ret = blk_co_flush(exp->blk); 1517 if (ret < 0) { 1518 error_setg_errno(&local_err, -ret, "flush failed"); 1519 } 1520 1521 break; 1522 case NBD_CMD_TRIM: 1523 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset, 1524 request.len); 1525 if (ret < 0) { 1526 error_setg_errno(&local_err, -ret, "discard failed"); 1527 } 1528 1529 break; 1530 default: 1531 error_setg(&local_err, "invalid request type (%" PRIu32 ") received", 1532 request.type); 1533 ret = -EINVAL; 1534 } 1535 1536 reply: 1537 if (local_err) { 1538 /* If we get here, local_err was not a fatal error, and should be sent 1539 * to the client. */ 1540 assert(ret < 0); 1541 msg = g_strdup(error_get_pretty(local_err)); 1542 error_report_err(local_err); 1543 local_err = NULL; 1544 } 1545 1546 if (client->structured_reply && 1547 (ret < 0 || request.type == NBD_CMD_READ)) { 1548 if (ret < 0) { 1549 ret = nbd_co_send_structured_error(req->client, request.handle, 1550 -ret, msg, &local_err); 1551 } else if (reply_data_len) { 1552 ret = nbd_co_send_structured_read(req->client, request.handle, 1553 request.from, req->data, 1554 reply_data_len, &local_err); 1555 } else { 1556 ret = nbd_co_send_structured_done(req->client, request.handle, 1557 &local_err); 1558 } 1559 } else { 1560 ret = nbd_co_send_simple_reply(req->client, request.handle, 1561 ret < 0 ? -ret : 0, 1562 req->data, reply_data_len, &local_err); 1563 } 1564 g_free(msg); 1565 if (ret < 0) { 1566 error_prepend(&local_err, "Failed to send reply: "); 1567 goto disconnect; 1568 } 1569 1570 /* We must disconnect after NBD_CMD_WRITE if we did not 1571 * read the payload. 1572 */ 1573 if (!req->complete) { 1574 error_setg(&local_err, "Request handling failed in intermediate state"); 1575 goto disconnect; 1576 } 1577 1578 done: 1579 nbd_request_put(req); 1580 nbd_client_put(client); 1581 return; 1582 1583 disconnect: 1584 if (local_err) { 1585 error_reportf_err(local_err, "Disconnect client, due to: "); 1586 } 1587 nbd_request_put(req); 1588 client_close(client, true); 1589 nbd_client_put(client); 1590 } 1591 1592 static void nbd_client_receive_next_request(NBDClient *client) 1593 { 1594 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 1595 nbd_client_get(client); 1596 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 1597 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 1598 } 1599 } 1600 1601 static coroutine_fn void nbd_co_client_start(void *opaque) 1602 { 1603 NBDClient *client = opaque; 1604 NBDExport *exp = client->exp; 1605 Error *local_err = NULL; 1606 1607 if (exp) { 1608 nbd_export_get(exp); 1609 QTAILQ_INSERT_TAIL(&exp->clients, client, next); 1610 } 1611 qemu_co_mutex_init(&client->send_lock); 1612 1613 if (nbd_negotiate(client, &local_err)) { 1614 if (local_err) { 1615 error_report_err(local_err); 1616 } 1617 client_close(client, false); 1618 return; 1619 } 1620 1621 nbd_client_receive_next_request(client); 1622 } 1623 1624 /* 1625 * Create a new client listener on the given export @exp, using the 1626 * given channel @sioc. Begin servicing it in a coroutine. When the 1627 * connection closes, call @close_fn with an indication of whether the 1628 * client completed negotiation. 1629 */ 1630 void nbd_client_new(NBDExport *exp, 1631 QIOChannelSocket *sioc, 1632 QCryptoTLSCreds *tlscreds, 1633 const char *tlsaclname, 1634 void (*close_fn)(NBDClient *, bool)) 1635 { 1636 NBDClient *client; 1637 Coroutine *co; 1638 1639 client = g_new0(NBDClient, 1); 1640 client->refcount = 1; 1641 client->exp = exp; 1642 client->tlscreds = tlscreds; 1643 if (tlscreds) { 1644 object_ref(OBJECT(client->tlscreds)); 1645 } 1646 client->tlsaclname = g_strdup(tlsaclname); 1647 client->sioc = sioc; 1648 object_ref(OBJECT(client->sioc)); 1649 client->ioc = QIO_CHANNEL(sioc); 1650 object_ref(OBJECT(client->ioc)); 1651 client->close_fn = close_fn; 1652 1653 co = qemu_coroutine_create(nbd_co_client_start, client); 1654 qemu_coroutine_enter(co); 1655 } 1656