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 } 1555