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 (namelen >= sizeof(name)) { 390 msg = "name too long for qemu"; 391 goto invalid; 392 } 393 if (nbd_read(client->ioc, name, namelen, errp) < 0) { 394 return -EIO; 395 } 396 name[namelen] = '\0'; 397 length -= namelen; 398 trace_nbd_negotiate_handle_export_name_request(name); 399 400 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) { 401 return -EIO; 402 } 403 be16_to_cpus(&requests); 404 length -= sizeof(requests); 405 trace_nbd_negotiate_handle_info_requests(requests); 406 if (requests != length / sizeof(request)) { 407 msg = "incorrect number of requests for overall length"; 408 goto invalid; 409 } 410 while (requests--) { 411 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) { 412 return -EIO; 413 } 414 be16_to_cpus(&request); 415 length -= sizeof(request); 416 trace_nbd_negotiate_handle_info_request(request, 417 nbd_info_lookup(request)); 418 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 419 * everything else is either a request we don't know or 420 * something we send regardless of request */ 421 switch (request) { 422 case NBD_INFO_NAME: 423 sendname = true; 424 break; 425 case NBD_INFO_BLOCK_SIZE: 426 blocksize = true; 427 break; 428 } 429 } 430 assert(length == 0); 431 432 exp = nbd_export_find(name); 433 if (!exp) { 434 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN, 435 opt, errp, "export '%s' not present", 436 name); 437 } 438 439 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 440 if (sendname) { 441 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, namelen, name, 442 errp); 443 if (rc < 0) { 444 return rc; 445 } 446 } 447 448 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 449 * client request */ 450 if (exp->description) { 451 size_t len = strlen(exp->description); 452 453 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION, 454 len, exp->description, errp); 455 if (rc < 0) { 456 return rc; 457 } 458 } 459 460 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 461 * according to whether the client requested it, and according to 462 * whether this is OPT_INFO or OPT_GO. */ 463 /* minimum - 1 for back-compat, or 512 if client is new enough. 464 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 465 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 466 /* preferred - Hard-code to 4096 for now. 467 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 468 sizes[1] = 4096; 469 /* maximum - At most 32M, but smaller as appropriate. */ 470 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 471 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 472 cpu_to_be32s(&sizes[0]); 473 cpu_to_be32s(&sizes[1]); 474 cpu_to_be32s(&sizes[2]); 475 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE, 476 sizeof(sizes), sizes, errp); 477 if (rc < 0) { 478 return rc; 479 } 480 481 /* Send NBD_INFO_EXPORT always */ 482 trace_nbd_negotiate_new_style_size_flags(exp->size, 483 exp->nbdflags | myflags); 484 stq_be_p(buf, exp->size); 485 stw_be_p(buf + 8, exp->nbdflags | myflags); 486 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT, 487 sizeof(buf), buf, errp); 488 if (rc < 0) { 489 return rc; 490 } 491 492 /* If the client is just asking for NBD_OPT_INFO, but forgot to 493 * request block sizes, return an error. 494 * TODO: consult blk_bs(blk)->request_align, and only error if it 495 * is not 1? */ 496 if (opt == NBD_OPT_INFO && !blocksize) { 497 return nbd_negotiate_send_rep_err(client->ioc, 498 NBD_REP_ERR_BLOCK_SIZE_REQD, opt, 499 errp, 500 "request NBD_INFO_BLOCK_SIZE to " 501 "use this export"); 502 } 503 504 /* Final reply */ 505 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp); 506 if (rc < 0) { 507 return rc; 508 } 509 510 if (opt == NBD_OPT_GO) { 511 client->exp = exp; 512 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 513 nbd_export_get(client->exp); 514 rc = 1; 515 } 516 return rc; 517 518 invalid: 519 if (nbd_drop(client->ioc, length, errp) < 0) { 520 return -EIO; 521 } 522 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt, 523 errp, "%s", msg); 524 } 525 526 527 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 528 * new channel for all further (now-encrypted) communication. */ 529 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 530 Error **errp) 531 { 532 QIOChannel *ioc; 533 QIOChannelTLS *tioc; 534 struct NBDTLSHandshakeData data = { 0 }; 535 536 trace_nbd_negotiate_handle_starttls(); 537 ioc = client->ioc; 538 539 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 540 NBD_OPT_STARTTLS, errp) < 0) { 541 return NULL; 542 } 543 544 tioc = qio_channel_tls_new_server(ioc, 545 client->tlscreds, 546 client->tlsaclname, 547 errp); 548 if (!tioc) { 549 return NULL; 550 } 551 552 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 553 trace_nbd_negotiate_handle_starttls_handshake(); 554 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 555 qio_channel_tls_handshake(tioc, 556 nbd_tls_handshake, 557 &data, 558 NULL); 559 560 if (!data.complete) { 561 g_main_loop_run(data.loop); 562 } 563 g_main_loop_unref(data.loop); 564 if (data.error) { 565 object_unref(OBJECT(tioc)); 566 error_propagate(errp, data.error); 567 return NULL; 568 } 569 570 return QIO_CHANNEL(tioc); 571 } 572 573 /* nbd_reject_length: Handle any unexpected payload. 574 * @fatal requests that we quit talking to the client, even if we are able 575 * to successfully send an error to the guest. 576 * Return: 577 * -errno transmission error occurred or @fatal was requested, errp is set 578 * 0 error message successfully sent to client, errp is not set 579 */ 580 static int nbd_reject_length(NBDClient *client, uint32_t length, 581 uint32_t option, bool fatal, Error **errp) 582 { 583 int ret; 584 585 assert(length); 586 if (nbd_drop(client->ioc, length, errp) < 0) { 587 return -EIO; 588 } 589 ret = nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, 590 option, errp, 591 "option '%s' should have zero length", 592 nbd_opt_lookup(option)); 593 if (fatal && !ret) { 594 error_setg(errp, "option '%s' should have zero length", 595 nbd_opt_lookup(option)); 596 return -EINVAL; 597 } 598 return ret; 599 } 600 601 /* nbd_negotiate_options 602 * Process all NBD_OPT_* client option commands, during fixed newstyle 603 * negotiation. 604 * Return: 605 * -errno on error, errp is set 606 * 0 on successful negotiation, errp is not set 607 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 608 * errp is not set 609 */ 610 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 611 Error **errp) 612 { 613 uint32_t flags; 614 bool fixedNewstyle = false; 615 bool no_zeroes = false; 616 617 /* Client sends: 618 [ 0 .. 3] client flags 619 620 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 621 [ 0 .. 7] NBD_OPTS_MAGIC 622 [ 8 .. 11] NBD option 623 [12 .. 15] Data length 624 ... Rest of request 625 626 [ 0 .. 7] NBD_OPTS_MAGIC 627 [ 8 .. 11] Second NBD option 628 [12 .. 15] Data length 629 ... Rest of request 630 */ 631 632 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 633 error_prepend(errp, "read failed: "); 634 return -EIO; 635 } 636 be32_to_cpus(&flags); 637 trace_nbd_negotiate_options_flags(flags); 638 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 639 fixedNewstyle = true; 640 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 641 } 642 if (flags & NBD_FLAG_C_NO_ZEROES) { 643 no_zeroes = true; 644 flags &= ~NBD_FLAG_C_NO_ZEROES; 645 } 646 if (flags != 0) { 647 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 648 return -EINVAL; 649 } 650 651 while (1) { 652 int ret; 653 uint32_t option, length; 654 uint64_t magic; 655 656 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 657 error_prepend(errp, "read failed: "); 658 return -EINVAL; 659 } 660 magic = be64_to_cpu(magic); 661 trace_nbd_negotiate_options_check_magic(magic); 662 if (magic != NBD_OPTS_MAGIC) { 663 error_setg(errp, "Bad magic received"); 664 return -EINVAL; 665 } 666 667 if (nbd_read(client->ioc, &option, 668 sizeof(option), errp) < 0) { 669 error_prepend(errp, "read failed: "); 670 return -EINVAL; 671 } 672 option = be32_to_cpu(option); 673 674 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 675 error_prepend(errp, "read failed: "); 676 return -EINVAL; 677 } 678 length = be32_to_cpu(length); 679 680 if (length > NBD_MAX_BUFFER_SIZE) { 681 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 682 length, NBD_MAX_BUFFER_SIZE); 683 return -EINVAL; 684 } 685 686 trace_nbd_negotiate_options_check_option(option, 687 nbd_opt_lookup(option)); 688 if (client->tlscreds && 689 client->ioc == (QIOChannel *)client->sioc) { 690 QIOChannel *tioc; 691 if (!fixedNewstyle) { 692 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 693 return -EINVAL; 694 } 695 switch (option) { 696 case NBD_OPT_STARTTLS: 697 if (length) { 698 /* Unconditionally drop the connection if the client 699 * can't start a TLS negotiation correctly */ 700 return nbd_reject_length(client, length, option, true, 701 errp); 702 } 703 tioc = nbd_negotiate_handle_starttls(client, errp); 704 if (!tioc) { 705 return -EIO; 706 } 707 ret = 0; 708 object_unref(OBJECT(client->ioc)); 709 client->ioc = QIO_CHANNEL(tioc); 710 break; 711 712 case NBD_OPT_EXPORT_NAME: 713 /* No way to return an error to client, so drop connection */ 714 error_setg(errp, "Option 0x%x not permitted before TLS", 715 option); 716 return -EINVAL; 717 718 default: 719 if (nbd_drop(client->ioc, length, errp) < 0) { 720 return -EIO; 721 } 722 ret = nbd_negotiate_send_rep_err(client->ioc, 723 NBD_REP_ERR_TLS_REQD, 724 option, errp, 725 "Option 0x%" PRIx32 726 "not permitted before TLS", 727 option); 728 /* Let the client keep trying, unless they asked to 729 * quit. In this mode, we've already sent an error, so 730 * we can't ack the abort. */ 731 if (option == NBD_OPT_ABORT) { 732 return 1; 733 } 734 break; 735 } 736 } else if (fixedNewstyle) { 737 switch (option) { 738 case NBD_OPT_LIST: 739 if (length) { 740 ret = nbd_reject_length(client, length, option, false, 741 errp); 742 } else { 743 ret = nbd_negotiate_handle_list(client, errp); 744 } 745 break; 746 747 case NBD_OPT_ABORT: 748 /* NBD spec says we must try to reply before 749 * disconnecting, but that we must also tolerate 750 * guests that don't wait for our reply. */ 751 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL); 752 return 1; 753 754 case NBD_OPT_EXPORT_NAME: 755 return nbd_negotiate_handle_export_name(client, length, 756 myflags, no_zeroes, 757 errp); 758 759 case NBD_OPT_INFO: 760 case NBD_OPT_GO: 761 ret = nbd_negotiate_handle_info(client, length, option, 762 myflags, errp); 763 if (ret == 1) { 764 assert(option == NBD_OPT_GO); 765 return 0; 766 } 767 break; 768 769 case NBD_OPT_STARTTLS: 770 if (length) { 771 ret = nbd_reject_length(client, length, option, false, 772 errp); 773 } else if (client->tlscreds) { 774 ret = nbd_negotiate_send_rep_err(client->ioc, 775 NBD_REP_ERR_INVALID, 776 option, errp, 777 "TLS already enabled"); 778 } else { 779 ret = nbd_negotiate_send_rep_err(client->ioc, 780 NBD_REP_ERR_POLICY, 781 option, errp, 782 "TLS not configured"); 783 } 784 break; 785 786 case NBD_OPT_STRUCTURED_REPLY: 787 if (length) { 788 ret = nbd_reject_length(client, length, option, false, 789 errp); 790 } else if (client->structured_reply) { 791 ret = nbd_negotiate_send_rep_err( 792 client->ioc, NBD_REP_ERR_INVALID, option, errp, 793 "structured reply already negotiated"); 794 } else { 795 ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 796 option, errp); 797 client->structured_reply = true; 798 myflags |= NBD_FLAG_SEND_DF; 799 } 800 break; 801 802 default: 803 if (nbd_drop(client->ioc, length, errp) < 0) { 804 return -EIO; 805 } 806 ret = nbd_negotiate_send_rep_err(client->ioc, 807 NBD_REP_ERR_UNSUP, 808 option, errp, 809 "Unsupported option 0x%" 810 PRIx32 " (%s)", option, 811 nbd_opt_lookup(option)); 812 break; 813 } 814 } else { 815 /* 816 * If broken new-style we should drop the connection 817 * for anything except NBD_OPT_EXPORT_NAME 818 */ 819 switch (option) { 820 case NBD_OPT_EXPORT_NAME: 821 return nbd_negotiate_handle_export_name(client, length, 822 myflags, no_zeroes, 823 errp); 824 825 default: 826 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)", 827 option, nbd_opt_lookup(option)); 828 return -EINVAL; 829 } 830 } 831 if (ret < 0) { 832 return ret; 833 } 834 } 835 } 836 837 /* nbd_negotiate 838 * Return: 839 * -errno on error, errp is set 840 * 0 on successful negotiation, errp is not set 841 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 842 * errp is not set 843 */ 844 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 845 { 846 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 847 int ret; 848 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 849 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 850 NBD_FLAG_SEND_WRITE_ZEROES); 851 bool oldStyle; 852 853 /* Old style negotiation header, no room for options 854 [ 0 .. 7] passwd ("NBDMAGIC") 855 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 856 [16 .. 23] size 857 [24 .. 27] export flags (zero-extended) 858 [28 .. 151] reserved (0) 859 860 New style negotiation header, client can send options 861 [ 0 .. 7] passwd ("NBDMAGIC") 862 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 863 [16 .. 17] server flags (0) 864 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 865 */ 866 867 qio_channel_set_blocking(client->ioc, false, NULL); 868 869 trace_nbd_negotiate_begin(); 870 memcpy(buf, "NBDMAGIC", 8); 871 872 oldStyle = client->exp != NULL && !client->tlscreds; 873 if (oldStyle) { 874 trace_nbd_negotiate_old_style(client->exp->size, 875 client->exp->nbdflags | myflags); 876 stq_be_p(buf + 8, NBD_CLIENT_MAGIC); 877 stq_be_p(buf + 16, client->exp->size); 878 stl_be_p(buf + 24, client->exp->nbdflags | myflags); 879 880 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) { 881 error_prepend(errp, "write failed: "); 882 return -EINVAL; 883 } 884 } else { 885 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 886 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 887 888 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 889 error_prepend(errp, "write failed: "); 890 return -EINVAL; 891 } 892 ret = nbd_negotiate_options(client, myflags, errp); 893 if (ret != 0) { 894 if (ret < 0) { 895 error_prepend(errp, "option negotiation failed: "); 896 } 897 return ret; 898 } 899 } 900 901 trace_nbd_negotiate_success(); 902 903 return 0; 904 } 905 906 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 907 Error **errp) 908 { 909 uint8_t buf[NBD_REQUEST_SIZE]; 910 uint32_t magic; 911 int ret; 912 913 ret = nbd_read(ioc, buf, sizeof(buf), errp); 914 if (ret < 0) { 915 return ret; 916 } 917 918 /* Request 919 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 920 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 921 [ 6 .. 7] type (NBD_CMD_READ, ...) 922 [ 8 .. 15] handle 923 [16 .. 23] from 924 [24 .. 27] len 925 */ 926 927 magic = ldl_be_p(buf); 928 request->flags = lduw_be_p(buf + 4); 929 request->type = lduw_be_p(buf + 6); 930 request->handle = ldq_be_p(buf + 8); 931 request->from = ldq_be_p(buf + 16); 932 request->len = ldl_be_p(buf + 24); 933 934 trace_nbd_receive_request(magic, request->flags, request->type, 935 request->from, request->len); 936 937 if (magic != NBD_REQUEST_MAGIC) { 938 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 939 return -EINVAL; 940 } 941 return 0; 942 } 943 944 #define MAX_NBD_REQUESTS 16 945 946 void nbd_client_get(NBDClient *client) 947 { 948 client->refcount++; 949 } 950 951 void nbd_client_put(NBDClient *client) 952 { 953 if (--client->refcount == 0) { 954 /* The last reference should be dropped by client->close, 955 * which is called by client_close. 956 */ 957 assert(client->closing); 958 959 qio_channel_detach_aio_context(client->ioc); 960 object_unref(OBJECT(client->sioc)); 961 object_unref(OBJECT(client->ioc)); 962 if (client->tlscreds) { 963 object_unref(OBJECT(client->tlscreds)); 964 } 965 g_free(client->tlsaclname); 966 if (client->exp) { 967 QTAILQ_REMOVE(&client->exp->clients, client, next); 968 nbd_export_put(client->exp); 969 } 970 g_free(client); 971 } 972 } 973 974 static void client_close(NBDClient *client, bool negotiated) 975 { 976 if (client->closing) { 977 return; 978 } 979 980 client->closing = true; 981 982 /* Force requests to finish. They will drop their own references, 983 * then we'll close the socket and free the NBDClient. 984 */ 985 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 986 NULL); 987 988 /* Also tell the client, so that they release their reference. */ 989 if (client->close_fn) { 990 client->close_fn(client, negotiated); 991 } 992 } 993 994 static NBDRequestData *nbd_request_get(NBDClient *client) 995 { 996 NBDRequestData *req; 997 998 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 999 client->nb_requests++; 1000 1001 req = g_new0(NBDRequestData, 1); 1002 nbd_client_get(client); 1003 req->client = client; 1004 return req; 1005 } 1006 1007 static void nbd_request_put(NBDRequestData *req) 1008 { 1009 NBDClient *client = req->client; 1010 1011 if (req->data) { 1012 qemu_vfree(req->data); 1013 } 1014 g_free(req); 1015 1016 client->nb_requests--; 1017 nbd_client_receive_next_request(client); 1018 1019 nbd_client_put(client); 1020 } 1021 1022 static void blk_aio_attached(AioContext *ctx, void *opaque) 1023 { 1024 NBDExport *exp = opaque; 1025 NBDClient *client; 1026 1027 trace_nbd_blk_aio_attached(exp->name, ctx); 1028 1029 exp->ctx = ctx; 1030 1031 QTAILQ_FOREACH(client, &exp->clients, next) { 1032 qio_channel_attach_aio_context(client->ioc, ctx); 1033 if (client->recv_coroutine) { 1034 aio_co_schedule(ctx, client->recv_coroutine); 1035 } 1036 if (client->send_coroutine) { 1037 aio_co_schedule(ctx, client->send_coroutine); 1038 } 1039 } 1040 } 1041 1042 static void blk_aio_detach(void *opaque) 1043 { 1044 NBDExport *exp = opaque; 1045 NBDClient *client; 1046 1047 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1048 1049 QTAILQ_FOREACH(client, &exp->clients, next) { 1050 qio_channel_detach_aio_context(client->ioc); 1051 } 1052 1053 exp->ctx = NULL; 1054 } 1055 1056 static void nbd_eject_notifier(Notifier *n, void *data) 1057 { 1058 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1059 nbd_export_close(exp); 1060 } 1061 1062 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 1063 uint16_t nbdflags, void (*close)(NBDExport *), 1064 bool writethrough, BlockBackend *on_eject_blk, 1065 Error **errp) 1066 { 1067 AioContext *ctx; 1068 BlockBackend *blk; 1069 NBDExport *exp = g_new0(NBDExport, 1); 1070 uint64_t perm; 1071 int ret; 1072 1073 /* 1074 * NBD exports are used for non-shared storage migration. Make sure 1075 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1076 * access since the export could be available before migration handover. 1077 */ 1078 ctx = bdrv_get_aio_context(bs); 1079 aio_context_acquire(ctx); 1080 bdrv_invalidate_cache(bs, NULL); 1081 aio_context_release(ctx); 1082 1083 /* Don't allow resize while the NBD server is running, otherwise we don't 1084 * care what happens with the node. */ 1085 perm = BLK_PERM_CONSISTENT_READ; 1086 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1087 perm |= BLK_PERM_WRITE; 1088 } 1089 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1090 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1091 ret = blk_insert_bs(blk, bs, errp); 1092 if (ret < 0) { 1093 goto fail; 1094 } 1095 blk_set_enable_write_cache(blk, !writethrough); 1096 1097 exp->refcount = 1; 1098 QTAILQ_INIT(&exp->clients); 1099 exp->blk = blk; 1100 exp->dev_offset = dev_offset; 1101 exp->nbdflags = nbdflags; 1102 exp->size = size < 0 ? blk_getlength(blk) : size; 1103 if (exp->size < 0) { 1104 error_setg_errno(errp, -exp->size, 1105 "Failed to determine the NBD export's length"); 1106 goto fail; 1107 } 1108 exp->size -= exp->size % BDRV_SECTOR_SIZE; 1109 1110 exp->close = close; 1111 exp->ctx = blk_get_aio_context(blk); 1112 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1113 1114 if (on_eject_blk) { 1115 blk_ref(on_eject_blk); 1116 exp->eject_notifier_blk = on_eject_blk; 1117 exp->eject_notifier.notify = nbd_eject_notifier; 1118 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1119 } 1120 return exp; 1121 1122 fail: 1123 blk_unref(blk); 1124 g_free(exp); 1125 return NULL; 1126 } 1127 1128 NBDExport *nbd_export_find(const char *name) 1129 { 1130 NBDExport *exp; 1131 QTAILQ_FOREACH(exp, &exports, next) { 1132 if (strcmp(name, exp->name) == 0) { 1133 return exp; 1134 } 1135 } 1136 1137 return NULL; 1138 } 1139 1140 void nbd_export_set_name(NBDExport *exp, const char *name) 1141 { 1142 if (exp->name == name) { 1143 return; 1144 } 1145 1146 nbd_export_get(exp); 1147 if (exp->name != NULL) { 1148 g_free(exp->name); 1149 exp->name = NULL; 1150 QTAILQ_REMOVE(&exports, exp, next); 1151 nbd_export_put(exp); 1152 } 1153 if (name != NULL) { 1154 nbd_export_get(exp); 1155 exp->name = g_strdup(name); 1156 QTAILQ_INSERT_TAIL(&exports, exp, next); 1157 } 1158 nbd_export_put(exp); 1159 } 1160 1161 void nbd_export_set_description(NBDExport *exp, const char *description) 1162 { 1163 g_free(exp->description); 1164 exp->description = g_strdup(description); 1165 } 1166 1167 void nbd_export_close(NBDExport *exp) 1168 { 1169 NBDClient *client, *next; 1170 1171 nbd_export_get(exp); 1172 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1173 client_close(client, true); 1174 } 1175 nbd_export_set_name(exp, NULL); 1176 nbd_export_set_description(exp, NULL); 1177 nbd_export_put(exp); 1178 } 1179 1180 void nbd_export_get(NBDExport *exp) 1181 { 1182 assert(exp->refcount > 0); 1183 exp->refcount++; 1184 } 1185 1186 void nbd_export_put(NBDExport *exp) 1187 { 1188 assert(exp->refcount > 0); 1189 if (exp->refcount == 1) { 1190 nbd_export_close(exp); 1191 } 1192 1193 if (--exp->refcount == 0) { 1194 assert(exp->name == NULL); 1195 assert(exp->description == NULL); 1196 1197 if (exp->close) { 1198 exp->close(exp); 1199 } 1200 1201 if (exp->blk) { 1202 if (exp->eject_notifier_blk) { 1203 notifier_remove(&exp->eject_notifier); 1204 blk_unref(exp->eject_notifier_blk); 1205 } 1206 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1207 blk_aio_detach, exp); 1208 blk_unref(exp->blk); 1209 exp->blk = NULL; 1210 } 1211 1212 g_free(exp); 1213 } 1214 } 1215 1216 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1217 { 1218 return exp->blk; 1219 } 1220 1221 void nbd_export_close_all(void) 1222 { 1223 NBDExport *exp, *next; 1224 1225 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1226 nbd_export_close(exp); 1227 } 1228 } 1229 1230 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1231 unsigned niov, Error **errp) 1232 { 1233 int ret; 1234 1235 g_assert(qemu_in_coroutine()); 1236 qemu_co_mutex_lock(&client->send_lock); 1237 client->send_coroutine = qemu_coroutine_self(); 1238 1239 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1240 1241 client->send_coroutine = NULL; 1242 qemu_co_mutex_unlock(&client->send_lock); 1243 1244 return ret; 1245 } 1246 1247 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1248 uint64_t handle) 1249 { 1250 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1251 stl_be_p(&reply->error, error); 1252 stq_be_p(&reply->handle, handle); 1253 } 1254 1255 static int nbd_co_send_simple_reply(NBDClient *client, 1256 uint64_t handle, 1257 uint32_t error, 1258 void *data, 1259 size_t len, 1260 Error **errp) 1261 { 1262 NBDSimpleReply reply; 1263 int nbd_err = system_errno_to_nbd_errno(error); 1264 struct iovec iov[] = { 1265 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1266 {.iov_base = data, .iov_len = len} 1267 }; 1268 1269 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1270 len); 1271 set_be_simple_reply(&reply, nbd_err, handle); 1272 1273 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1274 } 1275 1276 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1277 uint16_t type, uint64_t handle, uint32_t length) 1278 { 1279 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1280 stw_be_p(&chunk->flags, flags); 1281 stw_be_p(&chunk->type, type); 1282 stq_be_p(&chunk->handle, handle); 1283 stl_be_p(&chunk->length, length); 1284 } 1285 1286 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1287 uint64_t handle, 1288 Error **errp) 1289 { 1290 NBDStructuredReplyChunk chunk; 1291 struct iovec iov[] = { 1292 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1293 }; 1294 1295 trace_nbd_co_send_structured_done(handle); 1296 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1297 1298 return nbd_co_send_iov(client, iov, 1, errp); 1299 } 1300 1301 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1302 uint64_t handle, 1303 uint64_t offset, 1304 void *data, 1305 size_t size, 1306 bool final, 1307 Error **errp) 1308 { 1309 NBDStructuredReadData chunk; 1310 struct iovec iov[] = { 1311 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1312 {.iov_base = data, .iov_len = size} 1313 }; 1314 1315 assert(size); 1316 trace_nbd_co_send_structured_read(handle, offset, data, size); 1317 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1318 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1319 sizeof(chunk) - sizeof(chunk.h) + size); 1320 stq_be_p(&chunk.offset, offset); 1321 1322 return nbd_co_send_iov(client, iov, 2, errp); 1323 } 1324 1325 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1326 uint64_t handle, 1327 uint64_t offset, 1328 uint8_t *data, 1329 size_t size, 1330 Error **errp) 1331 { 1332 int ret = 0; 1333 NBDExport *exp = client->exp; 1334 size_t progress = 0; 1335 1336 while (progress < size) { 1337 int64_t pnum; 1338 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1339 offset + progress, 1340 size - progress, &pnum, NULL, 1341 NULL); 1342 bool final; 1343 1344 if (status < 0) { 1345 error_setg_errno(errp, -status, "unable to check for holes"); 1346 return status; 1347 } 1348 assert(pnum && pnum <= size - progress); 1349 final = progress + pnum == size; 1350 if (status & BDRV_BLOCK_ZERO) { 1351 NBDStructuredReadHole chunk; 1352 struct iovec iov[] = { 1353 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1354 }; 1355 1356 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1357 pnum); 1358 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1359 NBD_REPLY_TYPE_OFFSET_HOLE, 1360 handle, sizeof(chunk) - sizeof(chunk.h)); 1361 stq_be_p(&chunk.offset, offset + progress); 1362 stl_be_p(&chunk.length, pnum); 1363 ret = nbd_co_send_iov(client, iov, 1, errp); 1364 } else { 1365 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1366 data + progress, pnum); 1367 if (ret < 0) { 1368 error_setg_errno(errp, -ret, "reading from file failed"); 1369 break; 1370 } 1371 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1372 data + progress, pnum, final, 1373 errp); 1374 } 1375 1376 if (ret < 0) { 1377 break; 1378 } 1379 progress += pnum; 1380 } 1381 return ret; 1382 } 1383 1384 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1385 uint64_t handle, 1386 uint32_t error, 1387 const char *msg, 1388 Error **errp) 1389 { 1390 NBDStructuredError chunk; 1391 int nbd_err = system_errno_to_nbd_errno(error); 1392 struct iovec iov[] = { 1393 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1394 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1395 }; 1396 1397 assert(nbd_err); 1398 trace_nbd_co_send_structured_error(handle, nbd_err, 1399 nbd_err_lookup(nbd_err), msg ? msg : ""); 1400 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1401 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1402 stl_be_p(&chunk.error, nbd_err); 1403 stw_be_p(&chunk.message_length, iov[1].iov_len); 1404 1405 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1406 } 1407 1408 /* nbd_co_receive_request 1409 * Collect a client request. Return 0 if request looks valid, -EIO to drop 1410 * connection right away, and any other negative value to report an error to 1411 * the client (although the caller may still need to disconnect after reporting 1412 * the error). 1413 */ 1414 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 1415 Error **errp) 1416 { 1417 NBDClient *client = req->client; 1418 int valid_flags; 1419 1420 g_assert(qemu_in_coroutine()); 1421 assert(client->recv_coroutine == qemu_coroutine_self()); 1422 if (nbd_receive_request(client->ioc, request, errp) < 0) { 1423 return -EIO; 1424 } 1425 1426 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 1427 nbd_cmd_lookup(request->type)); 1428 1429 if (request->type != NBD_CMD_WRITE) { 1430 /* No payload, we are ready to read the next request. */ 1431 req->complete = true; 1432 } 1433 1434 if (request->type == NBD_CMD_DISC) { 1435 /* Special case: we're going to disconnect without a reply, 1436 * whether or not flags, from, or len are bogus */ 1437 return -EIO; 1438 } 1439 1440 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { 1441 if (request->len > NBD_MAX_BUFFER_SIZE) { 1442 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1443 request->len, NBD_MAX_BUFFER_SIZE); 1444 return -EINVAL; 1445 } 1446 1447 req->data = blk_try_blockalign(client->exp->blk, request->len); 1448 if (req->data == NULL) { 1449 error_setg(errp, "No memory"); 1450 return -ENOMEM; 1451 } 1452 } 1453 if (request->type == NBD_CMD_WRITE) { 1454 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 1455 error_prepend(errp, "reading from socket failed: "); 1456 return -EIO; 1457 } 1458 req->complete = true; 1459 1460 trace_nbd_co_receive_request_payload_received(request->handle, 1461 request->len); 1462 } 1463 1464 /* Sanity checks. */ 1465 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 1466 (request->type == NBD_CMD_WRITE || 1467 request->type == NBD_CMD_WRITE_ZEROES || 1468 request->type == NBD_CMD_TRIM)) { 1469 error_setg(errp, "Export is read-only"); 1470 return -EROFS; 1471 } 1472 if (request->from > client->exp->size || 1473 request->from + request->len > client->exp->size) { 1474 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 1475 ", Size: %" PRIu64, request->from, request->len, 1476 (uint64_t)client->exp->size); 1477 return (request->type == NBD_CMD_WRITE || 1478 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 1479 } 1480 valid_flags = NBD_CMD_FLAG_FUA; 1481 if (request->type == NBD_CMD_READ && client->structured_reply) { 1482 valid_flags |= NBD_CMD_FLAG_DF; 1483 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 1484 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 1485 } 1486 if (request->flags & ~valid_flags) { 1487 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 1488 nbd_cmd_lookup(request->type), request->flags); 1489 return -EINVAL; 1490 } 1491 1492 return 0; 1493 } 1494 1495 /* Owns a reference to the NBDClient passed as opaque. */ 1496 static coroutine_fn void nbd_trip(void *opaque) 1497 { 1498 NBDClient *client = opaque; 1499 NBDExport *exp = client->exp; 1500 NBDRequestData *req; 1501 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 1502 int ret; 1503 int flags; 1504 int reply_data_len = 0; 1505 Error *local_err = NULL; 1506 char *msg = NULL; 1507 1508 trace_nbd_trip(); 1509 if (client->closing) { 1510 nbd_client_put(client); 1511 return; 1512 } 1513 1514 req = nbd_request_get(client); 1515 ret = nbd_co_receive_request(req, &request, &local_err); 1516 client->recv_coroutine = NULL; 1517 nbd_client_receive_next_request(client); 1518 if (ret == -EIO) { 1519 goto disconnect; 1520 } 1521 1522 if (ret < 0) { 1523 goto reply; 1524 } 1525 1526 if (client->closing) { 1527 /* 1528 * The client may be closed when we are blocked in 1529 * nbd_co_receive_request() 1530 */ 1531 goto done; 1532 } 1533 1534 switch (request.type) { 1535 case NBD_CMD_READ: 1536 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 1537 if (request.flags & NBD_CMD_FLAG_FUA) { 1538 ret = blk_co_flush(exp->blk); 1539 if (ret < 0) { 1540 error_setg_errno(&local_err, -ret, "flush failed"); 1541 break; 1542 } 1543 } 1544 1545 if (client->structured_reply && !(request.flags & NBD_CMD_FLAG_DF) && 1546 request.len) { 1547 ret = nbd_co_send_sparse_read(req->client, request.handle, 1548 request.from, req->data, request.len, 1549 &local_err); 1550 if (ret < 0) { 1551 goto reply; 1552 } 1553 goto done; 1554 } 1555 1556 ret = blk_pread(exp->blk, request.from + exp->dev_offset, 1557 req->data, request.len); 1558 if (ret < 0) { 1559 error_setg_errno(&local_err, -ret, "reading from file failed"); 1560 break; 1561 } 1562 1563 reply_data_len = request.len; 1564 1565 break; 1566 case NBD_CMD_WRITE: 1567 flags = 0; 1568 if (request.flags & NBD_CMD_FLAG_FUA) { 1569 flags |= BDRV_REQ_FUA; 1570 } 1571 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset, 1572 req->data, request.len, flags); 1573 if (ret < 0) { 1574 error_setg_errno(&local_err, -ret, "writing to file failed"); 1575 } 1576 1577 break; 1578 case NBD_CMD_WRITE_ZEROES: 1579 flags = 0; 1580 if (request.flags & NBD_CMD_FLAG_FUA) { 1581 flags |= BDRV_REQ_FUA; 1582 } 1583 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) { 1584 flags |= BDRV_REQ_MAY_UNMAP; 1585 } 1586 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset, 1587 request.len, flags); 1588 if (ret < 0) { 1589 error_setg_errno(&local_err, -ret, "writing to file failed"); 1590 } 1591 1592 break; 1593 case NBD_CMD_DISC: 1594 /* unreachable, thanks to special case in nbd_co_receive_request() */ 1595 abort(); 1596 1597 case NBD_CMD_FLUSH: 1598 ret = blk_co_flush(exp->blk); 1599 if (ret < 0) { 1600 error_setg_errno(&local_err, -ret, "flush failed"); 1601 } 1602 1603 break; 1604 case NBD_CMD_TRIM: 1605 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset, 1606 request.len); 1607 if (ret < 0) { 1608 error_setg_errno(&local_err, -ret, "discard failed"); 1609 } 1610 1611 break; 1612 default: 1613 error_setg(&local_err, "invalid request type (%" PRIu32 ") received", 1614 request.type); 1615 ret = -EINVAL; 1616 } 1617 1618 reply: 1619 if (local_err) { 1620 /* If we get here, local_err was not a fatal error, and should be sent 1621 * to the client. */ 1622 assert(ret < 0); 1623 msg = g_strdup(error_get_pretty(local_err)); 1624 error_report_err(local_err); 1625 local_err = NULL; 1626 } 1627 1628 if (client->structured_reply && 1629 (ret < 0 || request.type == NBD_CMD_READ)) { 1630 if (ret < 0) { 1631 ret = nbd_co_send_structured_error(req->client, request.handle, 1632 -ret, msg, &local_err); 1633 } else if (reply_data_len) { 1634 ret = nbd_co_send_structured_read(req->client, request.handle, 1635 request.from, req->data, 1636 reply_data_len, true, 1637 &local_err); 1638 } else { 1639 ret = nbd_co_send_structured_done(req->client, request.handle, 1640 &local_err); 1641 } 1642 } else { 1643 ret = nbd_co_send_simple_reply(req->client, request.handle, 1644 ret < 0 ? -ret : 0, 1645 req->data, reply_data_len, &local_err); 1646 } 1647 g_free(msg); 1648 if (ret < 0) { 1649 error_prepend(&local_err, "Failed to send reply: "); 1650 goto disconnect; 1651 } 1652 1653 /* We must disconnect after NBD_CMD_WRITE if we did not 1654 * read the payload. 1655 */ 1656 if (!req->complete) { 1657 error_setg(&local_err, "Request handling failed in intermediate state"); 1658 goto disconnect; 1659 } 1660 1661 done: 1662 nbd_request_put(req); 1663 nbd_client_put(client); 1664 return; 1665 1666 disconnect: 1667 if (local_err) { 1668 error_reportf_err(local_err, "Disconnect client, due to: "); 1669 } 1670 nbd_request_put(req); 1671 client_close(client, true); 1672 nbd_client_put(client); 1673 } 1674 1675 static void nbd_client_receive_next_request(NBDClient *client) 1676 { 1677 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 1678 nbd_client_get(client); 1679 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 1680 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 1681 } 1682 } 1683 1684 static coroutine_fn void nbd_co_client_start(void *opaque) 1685 { 1686 NBDClient *client = opaque; 1687 NBDExport *exp = client->exp; 1688 Error *local_err = NULL; 1689 1690 if (exp) { 1691 nbd_export_get(exp); 1692 QTAILQ_INSERT_TAIL(&exp->clients, client, next); 1693 } 1694 qemu_co_mutex_init(&client->send_lock); 1695 1696 if (nbd_negotiate(client, &local_err)) { 1697 if (local_err) { 1698 error_report_err(local_err); 1699 } 1700 client_close(client, false); 1701 return; 1702 } 1703 1704 nbd_client_receive_next_request(client); 1705 } 1706 1707 /* 1708 * Create a new client listener on the given export @exp, using the 1709 * given channel @sioc. Begin servicing it in a coroutine. When the 1710 * connection closes, call @close_fn with an indication of whether the 1711 * client completed negotiation. 1712 */ 1713 void nbd_client_new(NBDExport *exp, 1714 QIOChannelSocket *sioc, 1715 QCryptoTLSCreds *tlscreds, 1716 const char *tlsaclname, 1717 void (*close_fn)(NBDClient *, bool)) 1718 { 1719 NBDClient *client; 1720 Coroutine *co; 1721 1722 client = g_new0(NBDClient, 1); 1723 client->refcount = 1; 1724 client->exp = exp; 1725 client->tlscreds = tlscreds; 1726 if (tlscreds) { 1727 object_ref(OBJECT(client->tlscreds)); 1728 } 1729 client->tlsaclname = g_strdup(tlsaclname); 1730 client->sioc = sioc; 1731 object_ref(OBJECT(client->sioc)); 1732 client->ioc = QIO_CHANNEL(sioc); 1733 object_ref(OBJECT(client->ioc)); 1734 client->close_fn = close_fn; 1735 1736 co = qemu_coroutine_create(nbd_co_client_start, client); 1737 qemu_coroutine_enter(co); 1738 } 1739