1 /* 2 * Copyright (C) 2016-2018 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 #define NBD_META_ID_BASE_ALLOCATION 0 26 #define NBD_META_ID_DIRTY_BITMAP 1 27 28 /* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical 29 * constant. If an increase is needed, note that the NBD protocol 30 * recommends no larger than 32 mb, so that the client won't consider 31 * the reply as a denial of service attack. */ 32 #define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8) 33 34 static int system_errno_to_nbd_errno(int err) 35 { 36 switch (err) { 37 case 0: 38 return NBD_SUCCESS; 39 case EPERM: 40 case EROFS: 41 return NBD_EPERM; 42 case EIO: 43 return NBD_EIO; 44 case ENOMEM: 45 return NBD_ENOMEM; 46 #ifdef EDQUOT 47 case EDQUOT: 48 #endif 49 case EFBIG: 50 case ENOSPC: 51 return NBD_ENOSPC; 52 case EOVERFLOW: 53 return NBD_EOVERFLOW; 54 case ESHUTDOWN: 55 return NBD_ESHUTDOWN; 56 case EINVAL: 57 default: 58 return NBD_EINVAL; 59 } 60 } 61 62 /* Definitions for opaque data types */ 63 64 typedef struct NBDRequestData NBDRequestData; 65 66 struct NBDRequestData { 67 QSIMPLEQ_ENTRY(NBDRequestData) entry; 68 NBDClient *client; 69 uint8_t *data; 70 bool complete; 71 }; 72 73 struct NBDExport { 74 int refcount; 75 void (*close)(NBDExport *exp); 76 77 BlockBackend *blk; 78 char *name; 79 char *description; 80 off_t dev_offset; 81 off_t size; 82 uint16_t nbdflags; 83 QTAILQ_HEAD(, NBDClient) clients; 84 QTAILQ_ENTRY(NBDExport) next; 85 86 AioContext *ctx; 87 88 BlockBackend *eject_notifier_blk; 89 Notifier eject_notifier; 90 91 BdrvDirtyBitmap *export_bitmap; 92 char *export_bitmap_context; 93 }; 94 95 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 96 97 /* NBDExportMetaContexts represents a list of contexts to be exported, 98 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 99 * NBD_OPT_LIST_META_CONTEXT. */ 100 typedef struct NBDExportMetaContexts { 101 NBDExport *exp; 102 bool valid; /* means that negotiation of the option finished without 103 errors */ 104 bool base_allocation; /* export base:allocation context (block status) */ 105 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ 106 } NBDExportMetaContexts; 107 108 struct NBDClient { 109 int refcount; 110 void (*close_fn)(NBDClient *client, bool negotiated); 111 112 NBDExport *exp; 113 QCryptoTLSCreds *tlscreds; 114 char *tlsaclname; 115 QIOChannelSocket *sioc; /* The underlying data channel */ 116 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 117 118 Coroutine *recv_coroutine; 119 120 CoMutex send_lock; 121 Coroutine *send_coroutine; 122 123 QTAILQ_ENTRY(NBDClient) next; 124 int nb_requests; 125 bool closing; 126 127 bool structured_reply; 128 NBDExportMetaContexts export_meta; 129 130 uint32_t opt; /* Current option being negotiated */ 131 uint32_t optlen; /* remaining length of data in ioc for the option being 132 negotiated now */ 133 }; 134 135 static void nbd_client_receive_next_request(NBDClient *client); 136 137 /* Basic flow for negotiation 138 139 Server Client 140 Negotiate 141 142 or 143 144 Server Client 145 Negotiate #1 146 Option 147 Negotiate #2 148 149 ---- 150 151 followed by 152 153 Server Client 154 Request 155 Response 156 Request 157 Response 158 ... 159 ... 160 Request (type == 2) 161 162 */ 163 164 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 165 uint32_t type, uint32_t length) 166 { 167 stq_be_p(&rep->magic, NBD_REP_MAGIC); 168 stl_be_p(&rep->option, option); 169 stl_be_p(&rep->type, type); 170 stl_be_p(&rep->length, length); 171 } 172 173 /* Send a reply header, including length, but no payload. 174 * Return -errno on error, 0 on success. */ 175 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 176 uint32_t len, Error **errp) 177 { 178 NBDOptionReply rep; 179 180 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 181 type, nbd_rep_lookup(type), len); 182 183 assert(len < NBD_MAX_BUFFER_SIZE); 184 185 set_be_option_rep(&rep, client->opt, type, len); 186 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 187 } 188 189 /* Send a reply header with default 0 length. 190 * Return -errno on error, 0 on success. */ 191 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 192 Error **errp) 193 { 194 return nbd_negotiate_send_rep_len(client, type, 0, errp); 195 } 196 197 /* Send an error reply. 198 * Return -errno on error, 0 on success. */ 199 static int GCC_FMT_ATTR(4, 0) 200 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 201 Error **errp, const char *fmt, va_list va) 202 { 203 char *msg; 204 int ret; 205 size_t len; 206 207 msg = g_strdup_vprintf(fmt, va); 208 len = strlen(msg); 209 assert(len < 4096); 210 trace_nbd_negotiate_send_rep_err(msg); 211 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 212 if (ret < 0) { 213 goto out; 214 } 215 if (nbd_write(client->ioc, msg, len, errp) < 0) { 216 error_prepend(errp, "write failed (error message): "); 217 ret = -EIO; 218 } else { 219 ret = 0; 220 } 221 222 out: 223 g_free(msg); 224 return ret; 225 } 226 227 /* Send an error reply. 228 * Return -errno on error, 0 on success. */ 229 static int GCC_FMT_ATTR(4, 5) 230 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 231 Error **errp, const char *fmt, ...) 232 { 233 va_list va; 234 int ret; 235 236 va_start(va, fmt); 237 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 238 va_end(va); 239 return ret; 240 } 241 242 /* Drop remainder of the current option, and send a reply with the 243 * given error type and message. Return -errno on read or write 244 * failure; or 0 if connection is still live. */ 245 static int GCC_FMT_ATTR(4, 0) 246 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 247 const char *fmt, va_list va) 248 { 249 int ret = nbd_drop(client->ioc, client->optlen, errp); 250 251 client->optlen = 0; 252 if (!ret) { 253 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 254 } 255 return ret; 256 } 257 258 static int GCC_FMT_ATTR(4, 5) 259 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 260 const char *fmt, ...) 261 { 262 int ret; 263 va_list va; 264 265 va_start(va, fmt); 266 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 267 va_end(va); 268 269 return ret; 270 } 271 272 static int GCC_FMT_ATTR(3, 4) 273 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 274 { 275 int ret; 276 va_list va; 277 278 va_start(va, fmt); 279 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 280 va_end(va); 281 282 return ret; 283 } 284 285 /* Read size bytes from the unparsed payload of the current option. 286 * Return -errno on I/O error, 0 if option was completely handled by 287 * sending a reply about inconsistent lengths, or 1 on success. */ 288 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 289 Error **errp) 290 { 291 if (size > client->optlen) { 292 return nbd_opt_invalid(client, errp, 293 "Inconsistent lengths in option %s", 294 nbd_opt_lookup(client->opt)); 295 } 296 client->optlen -= size; 297 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 298 } 299 300 /* Drop size bytes from the unparsed payload of the current option. 301 * Return -errno on I/O error, 0 if option was completely handled by 302 * sending a reply about inconsistent lengths, or 1 on success. */ 303 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 304 { 305 if (size > client->optlen) { 306 return nbd_opt_invalid(client, errp, 307 "Inconsistent lengths in option %s", 308 nbd_opt_lookup(client->opt)); 309 } 310 client->optlen -= size; 311 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 312 } 313 314 /* nbd_opt_read_name 315 * 316 * Read a string with the format: 317 * uint32_t len (<= NBD_MAX_NAME_SIZE) 318 * len bytes string (not 0-terminated) 319 * 320 * @name should be enough to store NBD_MAX_NAME_SIZE+1. 321 * If @length is non-null, it will be set to the actual string length. 322 * 323 * Return -errno on I/O error, 0 if option was completely handled by 324 * sending a reply about inconsistent lengths, or 1 on success. 325 */ 326 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length, 327 Error **errp) 328 { 329 int ret; 330 uint32_t len; 331 332 ret = nbd_opt_read(client, &len, sizeof(len), errp); 333 if (ret <= 0) { 334 return ret; 335 } 336 len = cpu_to_be32(len); 337 338 if (len > NBD_MAX_NAME_SIZE) { 339 return nbd_opt_invalid(client, errp, 340 "Invalid name length: %" PRIu32, len); 341 } 342 343 ret = nbd_opt_read(client, name, len, errp); 344 if (ret <= 0) { 345 return ret; 346 } 347 name[len] = '\0'; 348 349 if (length) { 350 *length = len; 351 } 352 353 return 1; 354 } 355 356 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 357 * Return -errno on error, 0 on success. */ 358 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 359 Error **errp) 360 { 361 size_t name_len, desc_len; 362 uint32_t len; 363 const char *name = exp->name ? exp->name : ""; 364 const char *desc = exp->description ? exp->description : ""; 365 QIOChannel *ioc = client->ioc; 366 int ret; 367 368 trace_nbd_negotiate_send_rep_list(name, desc); 369 name_len = strlen(name); 370 desc_len = strlen(desc); 371 len = name_len + desc_len + sizeof(len); 372 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 373 if (ret < 0) { 374 return ret; 375 } 376 377 len = cpu_to_be32(name_len); 378 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 379 error_prepend(errp, "write failed (name length): "); 380 return -EINVAL; 381 } 382 383 if (nbd_write(ioc, name, name_len, errp) < 0) { 384 error_prepend(errp, "write failed (name buffer): "); 385 return -EINVAL; 386 } 387 388 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 389 error_prepend(errp, "write failed (description buffer): "); 390 return -EINVAL; 391 } 392 393 return 0; 394 } 395 396 /* Process the NBD_OPT_LIST command, with a potential series of replies. 397 * Return -errno on error, 0 on success. */ 398 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 399 { 400 NBDExport *exp; 401 assert(client->opt == NBD_OPT_LIST); 402 403 /* For each export, send a NBD_REP_SERVER reply. */ 404 QTAILQ_FOREACH(exp, &exports, next) { 405 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 406 return -EINVAL; 407 } 408 } 409 /* Finish with a NBD_REP_ACK. */ 410 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 411 } 412 413 static void nbd_check_meta_export(NBDClient *client) 414 { 415 client->export_meta.valid &= client->exp == client->export_meta.exp; 416 } 417 418 /* Send a reply to NBD_OPT_EXPORT_NAME. 419 * Return -errno on error, 0 on success. */ 420 static int nbd_negotiate_handle_export_name(NBDClient *client, 421 uint16_t myflags, bool no_zeroes, 422 Error **errp) 423 { 424 char name[NBD_MAX_NAME_SIZE + 1]; 425 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 426 size_t len; 427 int ret; 428 429 /* Client sends: 430 [20 .. xx] export name (length bytes) 431 Server replies: 432 [ 0 .. 7] size 433 [ 8 .. 9] export flags 434 [10 .. 133] reserved (0) [unless no_zeroes] 435 */ 436 trace_nbd_negotiate_handle_export_name(); 437 if (client->optlen >= sizeof(name)) { 438 error_setg(errp, "Bad length received"); 439 return -EINVAL; 440 } 441 if (nbd_read(client->ioc, name, client->optlen, errp) < 0) { 442 error_prepend(errp, "read failed: "); 443 return -EIO; 444 } 445 name[client->optlen] = '\0'; 446 client->optlen = 0; 447 448 trace_nbd_negotiate_handle_export_name_request(name); 449 450 client->exp = nbd_export_find(name); 451 if (!client->exp) { 452 error_setg(errp, "export not found"); 453 return -EINVAL; 454 } 455 456 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 457 client->exp->nbdflags | myflags); 458 stq_be_p(buf, client->exp->size); 459 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 460 len = no_zeroes ? 10 : sizeof(buf); 461 ret = nbd_write(client->ioc, buf, len, errp); 462 if (ret < 0) { 463 error_prepend(errp, "write failed: "); 464 return ret; 465 } 466 467 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 468 nbd_export_get(client->exp); 469 nbd_check_meta_export(client); 470 471 return 0; 472 } 473 474 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 475 * The buffer does NOT include the info type prefix. 476 * Return -errno on error, 0 if ready to send more. */ 477 static int nbd_negotiate_send_info(NBDClient *client, 478 uint16_t info, uint32_t length, void *buf, 479 Error **errp) 480 { 481 int rc; 482 483 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 484 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 485 sizeof(info) + length, errp); 486 if (rc < 0) { 487 return rc; 488 } 489 info = cpu_to_be16(info); 490 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 491 return -EIO; 492 } 493 if (nbd_write(client->ioc, buf, length, errp) < 0) { 494 return -EIO; 495 } 496 return 0; 497 } 498 499 /* nbd_reject_length: Handle any unexpected payload. 500 * @fatal requests that we quit talking to the client, even if we are able 501 * to successfully send an error reply. 502 * Return: 503 * -errno transmission error occurred or @fatal was requested, errp is set 504 * 0 error message successfully sent to client, errp is not set 505 */ 506 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 507 { 508 int ret; 509 510 assert(client->optlen); 511 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 512 nbd_opt_lookup(client->opt)); 513 if (fatal && !ret) { 514 error_setg(errp, "option '%s' has unexpected length", 515 nbd_opt_lookup(client->opt)); 516 return -EINVAL; 517 } 518 return ret; 519 } 520 521 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 522 * Return -errno on error, 0 if ready for next option, and 1 to move 523 * into transmission phase. */ 524 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 525 Error **errp) 526 { 527 int rc; 528 char name[NBD_MAX_NAME_SIZE + 1]; 529 NBDExport *exp; 530 uint16_t requests; 531 uint16_t request; 532 uint32_t namelen; 533 bool sendname = false; 534 bool blocksize = false; 535 uint32_t sizes[3]; 536 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 537 538 /* Client sends: 539 4 bytes: L, name length (can be 0) 540 L bytes: export name 541 2 bytes: N, number of requests (can be 0) 542 N * 2 bytes: N requests 543 */ 544 rc = nbd_opt_read_name(client, name, &namelen, errp); 545 if (rc <= 0) { 546 return rc; 547 } 548 trace_nbd_negotiate_handle_export_name_request(name); 549 550 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 551 if (rc <= 0) { 552 return rc; 553 } 554 requests = be16_to_cpu(requests); 555 trace_nbd_negotiate_handle_info_requests(requests); 556 while (requests--) { 557 rc = nbd_opt_read(client, &request, sizeof(request), errp); 558 if (rc <= 0) { 559 return rc; 560 } 561 request = be16_to_cpu(request); 562 trace_nbd_negotiate_handle_info_request(request, 563 nbd_info_lookup(request)); 564 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 565 * everything else is either a request we don't know or 566 * something we send regardless of request */ 567 switch (request) { 568 case NBD_INFO_NAME: 569 sendname = true; 570 break; 571 case NBD_INFO_BLOCK_SIZE: 572 blocksize = true; 573 break; 574 } 575 } 576 if (client->optlen) { 577 return nbd_reject_length(client, false, errp); 578 } 579 580 exp = nbd_export_find(name); 581 if (!exp) { 582 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 583 errp, "export '%s' not present", 584 name); 585 } 586 587 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 588 if (sendname) { 589 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 590 errp); 591 if (rc < 0) { 592 return rc; 593 } 594 } 595 596 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 597 * client request */ 598 if (exp->description) { 599 size_t len = strlen(exp->description); 600 601 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 602 len, exp->description, errp); 603 if (rc < 0) { 604 return rc; 605 } 606 } 607 608 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 609 * according to whether the client requested it, and according to 610 * whether this is OPT_INFO or OPT_GO. */ 611 /* minimum - 1 for back-compat, or 512 if client is new enough. 612 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 613 sizes[0] = 614 (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 615 /* preferred - Hard-code to 4096 for now. 616 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 617 sizes[1] = 4096; 618 /* maximum - At most 32M, but smaller as appropriate. */ 619 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 620 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 621 sizes[0] = cpu_to_be32(sizes[0]); 622 sizes[1] = cpu_to_be32(sizes[1]); 623 sizes[2] = cpu_to_be32(sizes[2]); 624 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 625 sizeof(sizes), sizes, errp); 626 if (rc < 0) { 627 return rc; 628 } 629 630 /* Send NBD_INFO_EXPORT always */ 631 trace_nbd_negotiate_new_style_size_flags(exp->size, 632 exp->nbdflags | myflags); 633 stq_be_p(buf, exp->size); 634 stw_be_p(buf + 8, exp->nbdflags | myflags); 635 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 636 sizeof(buf), buf, errp); 637 if (rc < 0) { 638 return rc; 639 } 640 641 /* If the client is just asking for NBD_OPT_INFO, but forgot to 642 * request block sizes, return an error. 643 * TODO: consult blk_bs(blk)->request_align, and only error if it 644 * is not 1? */ 645 if (client->opt == NBD_OPT_INFO && !blocksize) { 646 return nbd_negotiate_send_rep_err(client, 647 NBD_REP_ERR_BLOCK_SIZE_REQD, 648 errp, 649 "request NBD_INFO_BLOCK_SIZE to " 650 "use this export"); 651 } 652 653 /* Final reply */ 654 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 655 if (rc < 0) { 656 return rc; 657 } 658 659 if (client->opt == NBD_OPT_GO) { 660 client->exp = exp; 661 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 662 nbd_export_get(client->exp); 663 nbd_check_meta_export(client); 664 rc = 1; 665 } 666 return rc; 667 } 668 669 670 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 671 * new channel for all further (now-encrypted) communication. */ 672 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 673 Error **errp) 674 { 675 QIOChannel *ioc; 676 QIOChannelTLS *tioc; 677 struct NBDTLSHandshakeData data = { 0 }; 678 679 assert(client->opt == NBD_OPT_STARTTLS); 680 681 trace_nbd_negotiate_handle_starttls(); 682 ioc = client->ioc; 683 684 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 685 return NULL; 686 } 687 688 tioc = qio_channel_tls_new_server(ioc, 689 client->tlscreds, 690 client->tlsaclname, 691 errp); 692 if (!tioc) { 693 return NULL; 694 } 695 696 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 697 trace_nbd_negotiate_handle_starttls_handshake(); 698 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 699 qio_channel_tls_handshake(tioc, 700 nbd_tls_handshake, 701 &data, 702 NULL, 703 NULL); 704 705 if (!data.complete) { 706 g_main_loop_run(data.loop); 707 } 708 g_main_loop_unref(data.loop); 709 if (data.error) { 710 object_unref(OBJECT(tioc)); 711 error_propagate(errp, data.error); 712 return NULL; 713 } 714 715 return QIO_CHANNEL(tioc); 716 } 717 718 /* nbd_negotiate_send_meta_context 719 * 720 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 721 * 722 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 723 */ 724 static int nbd_negotiate_send_meta_context(NBDClient *client, 725 const char *context, 726 uint32_t context_id, 727 Error **errp) 728 { 729 NBDOptionReplyMetaContext opt; 730 struct iovec iov[] = { 731 {.iov_base = &opt, .iov_len = sizeof(opt)}, 732 {.iov_base = (void *)context, .iov_len = strlen(context)} 733 }; 734 735 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 736 context_id = 0; 737 } 738 739 trace_nbd_negotiate_meta_query_reply(context, context_id); 740 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 741 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 742 stl_be_p(&opt.context_id, context_id); 743 744 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 745 } 746 747 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 748 * @match is never set to false. 749 * 750 * Return -errno on I/O error, 0 if option was completely handled by 751 * sending a reply about inconsistent lengths, or 1 on success. 752 * 753 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 754 * It only means that there are no errors. 755 */ 756 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 757 Error **errp) 758 { 759 int ret; 760 char *query; 761 size_t len = strlen(pattern); 762 763 assert(len); 764 765 query = g_malloc(len); 766 ret = nbd_opt_read(client, query, len, errp); 767 if (ret <= 0) { 768 g_free(query); 769 return ret; 770 } 771 772 if (strncmp(query, pattern, len) == 0) { 773 trace_nbd_negotiate_meta_query_parse(pattern); 774 *match = true; 775 } else { 776 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 777 } 778 g_free(query); 779 780 return 1; 781 } 782 783 /* 784 * Read @len bytes, and set @match to true if they match @pattern, or if @len 785 * is 0 and the client is performing _LIST_. @match is never set to false. 786 * 787 * Return -errno on I/O error, 0 if option was completely handled by 788 * sending a reply about inconsistent lengths, or 1 on success. 789 * 790 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 791 * It only means that there are no errors. 792 */ 793 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 794 uint32_t len, bool *match, Error **errp) 795 { 796 if (len == 0) { 797 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 798 *match = true; 799 } 800 trace_nbd_negotiate_meta_query_parse("empty"); 801 return 1; 802 } 803 804 if (len != strlen(pattern)) { 805 trace_nbd_negotiate_meta_query_skip("different lengths"); 806 return nbd_opt_skip(client, len, errp); 807 } 808 809 return nbd_meta_pattern(client, pattern, match, errp); 810 } 811 812 /* nbd_meta_base_query 813 * 814 * Handle queries to 'base' namespace. For now, only the base:allocation 815 * context is available. 'len' is the amount of text remaining to be read from 816 * the current name, after the 'base:' portion has been stripped. 817 * 818 * Return -errno on I/O error, 0 if option was completely handled by 819 * sending a reply about inconsistent lengths, or 1 on success. 820 */ 821 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 822 uint32_t len, Error **errp) 823 { 824 return nbd_meta_empty_or_pattern(client, "allocation", len, 825 &meta->base_allocation, errp); 826 } 827 828 /* nbd_meta_bitmap_query 829 * 830 * Handle query to 'qemu:' namespace. 831 * @len is the amount of text remaining to be read from the current name, after 832 * the 'qemu:' portion has been stripped. 833 * 834 * Return -errno on I/O error, 0 if option was completely handled by 835 * sending a reply about inconsistent lengths, or 1 on success. */ 836 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 837 uint32_t len, Error **errp) 838 { 839 bool dirty_bitmap = false; 840 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 841 int ret; 842 843 if (!meta->exp->export_bitmap) { 844 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 845 return nbd_opt_skip(client, len, errp); 846 } 847 848 if (len == 0) { 849 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 850 meta->bitmap = true; 851 } 852 trace_nbd_negotiate_meta_query_parse("empty"); 853 return 1; 854 } 855 856 if (len < dirty_bitmap_len) { 857 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 858 return nbd_opt_skip(client, len, errp); 859 } 860 861 len -= dirty_bitmap_len; 862 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 863 if (ret <= 0) { 864 return ret; 865 } 866 if (!dirty_bitmap) { 867 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 868 return nbd_opt_skip(client, len, errp); 869 } 870 871 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 872 873 return nbd_meta_empty_or_pattern( 874 client, meta->exp->export_bitmap_context + 875 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 876 } 877 878 /* nbd_negotiate_meta_query 879 * 880 * Parse namespace name and call corresponding function to parse body of the 881 * query. 882 * 883 * The only supported namespace now is 'base'. 884 * 885 * The function aims not wasting time and memory to read long unknown namespace 886 * names. 887 * 888 * Return -errno on I/O error, 0 if option was completely handled by 889 * sending a reply about inconsistent lengths, or 1 on success. */ 890 static int nbd_negotiate_meta_query(NBDClient *client, 891 NBDExportMetaContexts *meta, Error **errp) 892 { 893 /* 894 * Both 'qemu' and 'base' namespaces have length = 5 including a 895 * colon. If another length namespace is later introduced, this 896 * should certainly be refactored. 897 */ 898 int ret; 899 size_t ns_len = 5; 900 char ns[5]; 901 uint32_t len; 902 903 ret = nbd_opt_read(client, &len, sizeof(len), errp); 904 if (ret <= 0) { 905 return ret; 906 } 907 len = cpu_to_be32(len); 908 909 if (len < ns_len) { 910 trace_nbd_negotiate_meta_query_skip("length too short"); 911 return nbd_opt_skip(client, len, errp); 912 } 913 914 len -= ns_len; 915 ret = nbd_opt_read(client, ns, ns_len, errp); 916 if (ret <= 0) { 917 return ret; 918 } 919 920 if (!strncmp(ns, "base:", ns_len)) { 921 trace_nbd_negotiate_meta_query_parse("base:"); 922 return nbd_meta_base_query(client, meta, len, errp); 923 } else if (!strncmp(ns, "qemu:", ns_len)) { 924 trace_nbd_negotiate_meta_query_parse("qemu:"); 925 return nbd_meta_qemu_query(client, meta, len, errp); 926 } 927 928 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 929 return nbd_opt_skip(client, len, errp); 930 } 931 932 /* nbd_negotiate_meta_queries 933 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 934 * 935 * Return -errno on I/O error, or 0 if option was completely handled. */ 936 static int nbd_negotiate_meta_queries(NBDClient *client, 937 NBDExportMetaContexts *meta, Error **errp) 938 { 939 int ret; 940 char export_name[NBD_MAX_NAME_SIZE + 1]; 941 NBDExportMetaContexts local_meta; 942 uint32_t nb_queries; 943 int i; 944 945 if (!client->structured_reply) { 946 return nbd_opt_invalid(client, errp, 947 "request option '%s' when structured reply " 948 "is not negotiated", 949 nbd_opt_lookup(client->opt)); 950 } 951 952 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 953 /* Only change the caller's meta on SET. */ 954 meta = &local_meta; 955 } 956 957 memset(meta, 0, sizeof(*meta)); 958 959 ret = nbd_opt_read_name(client, export_name, NULL, errp); 960 if (ret <= 0) { 961 return ret; 962 } 963 964 meta->exp = nbd_export_find(export_name); 965 if (meta->exp == NULL) { 966 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 967 "export '%s' not present", export_name); 968 } 969 970 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 971 if (ret <= 0) { 972 return ret; 973 } 974 nb_queries = cpu_to_be32(nb_queries); 975 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 976 export_name, nb_queries); 977 978 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 979 /* enable all known contexts */ 980 meta->base_allocation = true; 981 } else { 982 for (i = 0; i < nb_queries; ++i) { 983 ret = nbd_negotiate_meta_query(client, meta, errp); 984 if (ret <= 0) { 985 return ret; 986 } 987 } 988 } 989 990 if (meta->base_allocation) { 991 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 992 NBD_META_ID_BASE_ALLOCATION, 993 errp); 994 if (ret < 0) { 995 return ret; 996 } 997 } 998 999 if (meta->bitmap) { 1000 ret = nbd_negotiate_send_meta_context(client, 1001 meta->exp->export_bitmap_context, 1002 NBD_META_ID_DIRTY_BITMAP, 1003 errp); 1004 if (ret < 0) { 1005 return ret; 1006 } 1007 } 1008 1009 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1010 if (ret == 0) { 1011 meta->valid = true; 1012 } 1013 1014 return ret; 1015 } 1016 1017 /* nbd_negotiate_options 1018 * Process all NBD_OPT_* client option commands, during fixed newstyle 1019 * negotiation. 1020 * Return: 1021 * -errno on error, errp is set 1022 * 0 on successful negotiation, errp is not set 1023 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1024 * errp is not set 1025 */ 1026 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 1027 Error **errp) 1028 { 1029 uint32_t flags; 1030 bool fixedNewstyle = false; 1031 bool no_zeroes = false; 1032 1033 /* Client sends: 1034 [ 0 .. 3] client flags 1035 1036 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1037 [ 0 .. 7] NBD_OPTS_MAGIC 1038 [ 8 .. 11] NBD option 1039 [12 .. 15] Data length 1040 ... Rest of request 1041 1042 [ 0 .. 7] NBD_OPTS_MAGIC 1043 [ 8 .. 11] Second NBD option 1044 [12 .. 15] Data length 1045 ... Rest of request 1046 */ 1047 1048 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 1049 error_prepend(errp, "read failed: "); 1050 return -EIO; 1051 } 1052 flags = be32_to_cpu(flags); 1053 trace_nbd_negotiate_options_flags(flags); 1054 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1055 fixedNewstyle = true; 1056 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1057 } 1058 if (flags & NBD_FLAG_C_NO_ZEROES) { 1059 no_zeroes = true; 1060 flags &= ~NBD_FLAG_C_NO_ZEROES; 1061 } 1062 if (flags != 0) { 1063 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1064 return -EINVAL; 1065 } 1066 1067 while (1) { 1068 int ret; 1069 uint32_t option, length; 1070 uint64_t magic; 1071 1072 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 1073 error_prepend(errp, "read failed: "); 1074 return -EINVAL; 1075 } 1076 magic = be64_to_cpu(magic); 1077 trace_nbd_negotiate_options_check_magic(magic); 1078 if (magic != NBD_OPTS_MAGIC) { 1079 error_setg(errp, "Bad magic received"); 1080 return -EINVAL; 1081 } 1082 1083 if (nbd_read(client->ioc, &option, 1084 sizeof(option), errp) < 0) { 1085 error_prepend(errp, "read failed: "); 1086 return -EINVAL; 1087 } 1088 option = be32_to_cpu(option); 1089 client->opt = option; 1090 1091 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 1092 error_prepend(errp, "read failed: "); 1093 return -EINVAL; 1094 } 1095 length = be32_to_cpu(length); 1096 assert(!client->optlen); 1097 client->optlen = length; 1098 1099 if (length > NBD_MAX_BUFFER_SIZE) { 1100 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1101 length, NBD_MAX_BUFFER_SIZE); 1102 return -EINVAL; 1103 } 1104 1105 trace_nbd_negotiate_options_check_option(option, 1106 nbd_opt_lookup(option)); 1107 if (client->tlscreds && 1108 client->ioc == (QIOChannel *)client->sioc) { 1109 QIOChannel *tioc; 1110 if (!fixedNewstyle) { 1111 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1112 return -EINVAL; 1113 } 1114 switch (option) { 1115 case NBD_OPT_STARTTLS: 1116 if (length) { 1117 /* Unconditionally drop the connection if the client 1118 * can't start a TLS negotiation correctly */ 1119 return nbd_reject_length(client, true, errp); 1120 } 1121 tioc = nbd_negotiate_handle_starttls(client, errp); 1122 if (!tioc) { 1123 return -EIO; 1124 } 1125 ret = 0; 1126 object_unref(OBJECT(client->ioc)); 1127 client->ioc = QIO_CHANNEL(tioc); 1128 break; 1129 1130 case NBD_OPT_EXPORT_NAME: 1131 /* No way to return an error to client, so drop connection */ 1132 error_setg(errp, "Option 0x%x not permitted before TLS", 1133 option); 1134 return -EINVAL; 1135 1136 default: 1137 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, errp, 1138 "Option 0x%" PRIx32 1139 "not permitted before TLS", option); 1140 /* Let the client keep trying, unless they asked to 1141 * quit. In this mode, we've already sent an error, so 1142 * we can't ack the abort. */ 1143 if (option == NBD_OPT_ABORT) { 1144 return 1; 1145 } 1146 break; 1147 } 1148 } else if (fixedNewstyle) { 1149 switch (option) { 1150 case NBD_OPT_LIST: 1151 if (length) { 1152 ret = nbd_reject_length(client, false, errp); 1153 } else { 1154 ret = nbd_negotiate_handle_list(client, errp); 1155 } 1156 break; 1157 1158 case NBD_OPT_ABORT: 1159 /* NBD spec says we must try to reply before 1160 * disconnecting, but that we must also tolerate 1161 * guests that don't wait for our reply. */ 1162 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1163 return 1; 1164 1165 case NBD_OPT_EXPORT_NAME: 1166 return nbd_negotiate_handle_export_name(client, 1167 myflags, no_zeroes, 1168 errp); 1169 1170 case NBD_OPT_INFO: 1171 case NBD_OPT_GO: 1172 ret = nbd_negotiate_handle_info(client, myflags, errp); 1173 if (ret == 1) { 1174 assert(option == NBD_OPT_GO); 1175 return 0; 1176 } 1177 break; 1178 1179 case NBD_OPT_STARTTLS: 1180 if (length) { 1181 ret = nbd_reject_length(client, false, errp); 1182 } else if (client->tlscreds) { 1183 ret = nbd_negotiate_send_rep_err(client, 1184 NBD_REP_ERR_INVALID, errp, 1185 "TLS already enabled"); 1186 } else { 1187 ret = nbd_negotiate_send_rep_err(client, 1188 NBD_REP_ERR_POLICY, errp, 1189 "TLS not configured"); 1190 } 1191 break; 1192 1193 case NBD_OPT_STRUCTURED_REPLY: 1194 if (length) { 1195 ret = nbd_reject_length(client, false, errp); 1196 } else if (client->structured_reply) { 1197 ret = nbd_negotiate_send_rep_err( 1198 client, NBD_REP_ERR_INVALID, errp, 1199 "structured reply already negotiated"); 1200 } else { 1201 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1202 client->structured_reply = true; 1203 myflags |= NBD_FLAG_SEND_DF; 1204 } 1205 break; 1206 1207 case NBD_OPT_LIST_META_CONTEXT: 1208 case NBD_OPT_SET_META_CONTEXT: 1209 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1210 errp); 1211 break; 1212 1213 default: 1214 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1215 "Unsupported option %" PRIu32 " (%s)", 1216 option, nbd_opt_lookup(option)); 1217 break; 1218 } 1219 } else { 1220 /* 1221 * If broken new-style we should drop the connection 1222 * for anything except NBD_OPT_EXPORT_NAME 1223 */ 1224 switch (option) { 1225 case NBD_OPT_EXPORT_NAME: 1226 return nbd_negotiate_handle_export_name(client, 1227 myflags, no_zeroes, 1228 errp); 1229 1230 default: 1231 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1232 option, nbd_opt_lookup(option)); 1233 return -EINVAL; 1234 } 1235 } 1236 if (ret < 0) { 1237 return ret; 1238 } 1239 } 1240 } 1241 1242 /* nbd_negotiate 1243 * Return: 1244 * -errno on error, errp is set 1245 * 0 on successful negotiation, errp is not set 1246 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1247 * errp is not set 1248 */ 1249 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1250 { 1251 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1252 int ret; 1253 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 1254 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 1255 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); 1256 1257 /* Old style negotiation header, no room for options 1258 [ 0 .. 7] passwd ("NBDMAGIC") 1259 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1260 [16 .. 23] size 1261 [24 .. 27] export flags (zero-extended) 1262 [28 .. 151] reserved (0) 1263 1264 New style negotiation header, client can send options 1265 [ 0 .. 7] passwd ("NBDMAGIC") 1266 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1267 [16 .. 17] server flags (0) 1268 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1269 */ 1270 1271 qio_channel_set_blocking(client->ioc, false, NULL); 1272 1273 trace_nbd_negotiate_begin(); 1274 memcpy(buf, "NBDMAGIC", 8); 1275 1276 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1277 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1278 1279 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1280 error_prepend(errp, "write failed: "); 1281 return -EINVAL; 1282 } 1283 ret = nbd_negotiate_options(client, myflags, errp); 1284 if (ret != 0) { 1285 if (ret < 0) { 1286 error_prepend(errp, "option negotiation failed: "); 1287 } 1288 return ret; 1289 } 1290 1291 assert(!client->optlen); 1292 trace_nbd_negotiate_success(); 1293 1294 return 0; 1295 } 1296 1297 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1298 Error **errp) 1299 { 1300 uint8_t buf[NBD_REQUEST_SIZE]; 1301 uint32_t magic; 1302 int ret; 1303 1304 ret = nbd_read(ioc, buf, sizeof(buf), errp); 1305 if (ret < 0) { 1306 return ret; 1307 } 1308 1309 /* Request 1310 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1311 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1312 [ 6 .. 7] type (NBD_CMD_READ, ...) 1313 [ 8 .. 15] handle 1314 [16 .. 23] from 1315 [24 .. 27] len 1316 */ 1317 1318 magic = ldl_be_p(buf); 1319 request->flags = lduw_be_p(buf + 4); 1320 request->type = lduw_be_p(buf + 6); 1321 request->handle = ldq_be_p(buf + 8); 1322 request->from = ldq_be_p(buf + 16); 1323 request->len = ldl_be_p(buf + 24); 1324 1325 trace_nbd_receive_request(magic, request->flags, request->type, 1326 request->from, request->len); 1327 1328 if (magic != NBD_REQUEST_MAGIC) { 1329 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1330 return -EINVAL; 1331 } 1332 return 0; 1333 } 1334 1335 #define MAX_NBD_REQUESTS 16 1336 1337 void nbd_client_get(NBDClient *client) 1338 { 1339 client->refcount++; 1340 } 1341 1342 void nbd_client_put(NBDClient *client) 1343 { 1344 if (--client->refcount == 0) { 1345 /* The last reference should be dropped by client->close, 1346 * which is called by client_close. 1347 */ 1348 assert(client->closing); 1349 1350 qio_channel_detach_aio_context(client->ioc); 1351 object_unref(OBJECT(client->sioc)); 1352 object_unref(OBJECT(client->ioc)); 1353 if (client->tlscreds) { 1354 object_unref(OBJECT(client->tlscreds)); 1355 } 1356 g_free(client->tlsaclname); 1357 if (client->exp) { 1358 QTAILQ_REMOVE(&client->exp->clients, client, next); 1359 nbd_export_put(client->exp); 1360 } 1361 g_free(client); 1362 } 1363 } 1364 1365 static void client_close(NBDClient *client, bool negotiated) 1366 { 1367 if (client->closing) { 1368 return; 1369 } 1370 1371 client->closing = true; 1372 1373 /* Force requests to finish. They will drop their own references, 1374 * then we'll close the socket and free the NBDClient. 1375 */ 1376 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1377 NULL); 1378 1379 /* Also tell the client, so that they release their reference. */ 1380 if (client->close_fn) { 1381 client->close_fn(client, negotiated); 1382 } 1383 } 1384 1385 static NBDRequestData *nbd_request_get(NBDClient *client) 1386 { 1387 NBDRequestData *req; 1388 1389 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1390 client->nb_requests++; 1391 1392 req = g_new0(NBDRequestData, 1); 1393 nbd_client_get(client); 1394 req->client = client; 1395 return req; 1396 } 1397 1398 static void nbd_request_put(NBDRequestData *req) 1399 { 1400 NBDClient *client = req->client; 1401 1402 if (req->data) { 1403 qemu_vfree(req->data); 1404 } 1405 g_free(req); 1406 1407 client->nb_requests--; 1408 nbd_client_receive_next_request(client); 1409 1410 nbd_client_put(client); 1411 } 1412 1413 static void blk_aio_attached(AioContext *ctx, void *opaque) 1414 { 1415 NBDExport *exp = opaque; 1416 NBDClient *client; 1417 1418 trace_nbd_blk_aio_attached(exp->name, ctx); 1419 1420 exp->ctx = ctx; 1421 1422 QTAILQ_FOREACH(client, &exp->clients, next) { 1423 qio_channel_attach_aio_context(client->ioc, ctx); 1424 if (client->recv_coroutine) { 1425 aio_co_schedule(ctx, client->recv_coroutine); 1426 } 1427 if (client->send_coroutine) { 1428 aio_co_schedule(ctx, client->send_coroutine); 1429 } 1430 } 1431 } 1432 1433 static void blk_aio_detach(void *opaque) 1434 { 1435 NBDExport *exp = opaque; 1436 NBDClient *client; 1437 1438 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1439 1440 QTAILQ_FOREACH(client, &exp->clients, next) { 1441 qio_channel_detach_aio_context(client->ioc); 1442 } 1443 1444 exp->ctx = NULL; 1445 } 1446 1447 static void nbd_eject_notifier(Notifier *n, void *data) 1448 { 1449 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1450 nbd_export_close(exp); 1451 } 1452 1453 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 1454 uint16_t nbdflags, void (*close)(NBDExport *), 1455 bool writethrough, BlockBackend *on_eject_blk, 1456 Error **errp) 1457 { 1458 AioContext *ctx; 1459 BlockBackend *blk; 1460 NBDExport *exp = g_new0(NBDExport, 1); 1461 uint64_t perm; 1462 int ret; 1463 1464 /* 1465 * NBD exports are used for non-shared storage migration. Make sure 1466 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1467 * access since the export could be available before migration handover. 1468 */ 1469 ctx = bdrv_get_aio_context(bs); 1470 aio_context_acquire(ctx); 1471 bdrv_invalidate_cache(bs, NULL); 1472 aio_context_release(ctx); 1473 1474 /* Don't allow resize while the NBD server is running, otherwise we don't 1475 * care what happens with the node. */ 1476 perm = BLK_PERM_CONSISTENT_READ; 1477 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1478 perm |= BLK_PERM_WRITE; 1479 } 1480 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1481 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1482 ret = blk_insert_bs(blk, bs, errp); 1483 if (ret < 0) { 1484 goto fail; 1485 } 1486 blk_set_enable_write_cache(blk, !writethrough); 1487 1488 exp->refcount = 1; 1489 QTAILQ_INIT(&exp->clients); 1490 exp->blk = blk; 1491 exp->dev_offset = dev_offset; 1492 exp->nbdflags = nbdflags; 1493 exp->size = size < 0 ? blk_getlength(blk) : size; 1494 if (exp->size < 0) { 1495 error_setg_errno(errp, -exp->size, 1496 "Failed to determine the NBD export's length"); 1497 goto fail; 1498 } 1499 exp->size -= exp->size % BDRV_SECTOR_SIZE; 1500 1501 exp->close = close; 1502 exp->ctx = blk_get_aio_context(blk); 1503 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1504 1505 if (on_eject_blk) { 1506 blk_ref(on_eject_blk); 1507 exp->eject_notifier_blk = on_eject_blk; 1508 exp->eject_notifier.notify = nbd_eject_notifier; 1509 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1510 } 1511 return exp; 1512 1513 fail: 1514 blk_unref(blk); 1515 g_free(exp); 1516 return NULL; 1517 } 1518 1519 NBDExport *nbd_export_find(const char *name) 1520 { 1521 NBDExport *exp; 1522 QTAILQ_FOREACH(exp, &exports, next) { 1523 if (strcmp(name, exp->name) == 0) { 1524 return exp; 1525 } 1526 } 1527 1528 return NULL; 1529 } 1530 1531 void nbd_export_set_name(NBDExport *exp, const char *name) 1532 { 1533 if (exp->name == name) { 1534 return; 1535 } 1536 1537 nbd_export_get(exp); 1538 if (exp->name != NULL) { 1539 g_free(exp->name); 1540 exp->name = NULL; 1541 QTAILQ_REMOVE(&exports, exp, next); 1542 nbd_export_put(exp); 1543 } 1544 if (name != NULL) { 1545 nbd_export_get(exp); 1546 exp->name = g_strdup(name); 1547 QTAILQ_INSERT_TAIL(&exports, exp, next); 1548 } 1549 nbd_export_put(exp); 1550 } 1551 1552 void nbd_export_set_description(NBDExport *exp, const char *description) 1553 { 1554 g_free(exp->description); 1555 exp->description = g_strdup(description); 1556 } 1557 1558 void nbd_export_close(NBDExport *exp) 1559 { 1560 NBDClient *client, *next; 1561 1562 nbd_export_get(exp); 1563 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1564 client_close(client, true); 1565 } 1566 nbd_export_set_name(exp, NULL); 1567 nbd_export_set_description(exp, NULL); 1568 nbd_export_put(exp); 1569 } 1570 1571 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1572 { 1573 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1574 nbd_export_close(exp); 1575 return; 1576 } 1577 1578 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1579 1580 error_setg(errp, "export '%s' still in use", exp->name); 1581 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1582 } 1583 1584 void nbd_export_get(NBDExport *exp) 1585 { 1586 assert(exp->refcount > 0); 1587 exp->refcount++; 1588 } 1589 1590 void nbd_export_put(NBDExport *exp) 1591 { 1592 assert(exp->refcount > 0); 1593 if (exp->refcount == 1) { 1594 nbd_export_close(exp); 1595 } 1596 1597 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1598 * if someone calls nbd_export_put() on named export not through 1599 * nbd_export_set_name() when refcount is 1. So, let's assert that 1600 * it is > 0. 1601 */ 1602 assert(exp->refcount > 0); 1603 if (--exp->refcount == 0) { 1604 assert(exp->name == NULL); 1605 assert(exp->description == NULL); 1606 1607 if (exp->close) { 1608 exp->close(exp); 1609 } 1610 1611 if (exp->blk) { 1612 if (exp->eject_notifier_blk) { 1613 notifier_remove(&exp->eject_notifier); 1614 blk_unref(exp->eject_notifier_blk); 1615 } 1616 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1617 blk_aio_detach, exp); 1618 blk_unref(exp->blk); 1619 exp->blk = NULL; 1620 } 1621 1622 if (exp->export_bitmap) { 1623 bdrv_dirty_bitmap_set_qmp_locked(exp->export_bitmap, false); 1624 g_free(exp->export_bitmap_context); 1625 } 1626 1627 g_free(exp); 1628 } 1629 } 1630 1631 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1632 { 1633 return exp->blk; 1634 } 1635 1636 void nbd_export_close_all(void) 1637 { 1638 NBDExport *exp, *next; 1639 1640 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1641 nbd_export_close(exp); 1642 } 1643 } 1644 1645 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1646 unsigned niov, Error **errp) 1647 { 1648 int ret; 1649 1650 g_assert(qemu_in_coroutine()); 1651 qemu_co_mutex_lock(&client->send_lock); 1652 client->send_coroutine = qemu_coroutine_self(); 1653 1654 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1655 1656 client->send_coroutine = NULL; 1657 qemu_co_mutex_unlock(&client->send_lock); 1658 1659 return ret; 1660 } 1661 1662 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1663 uint64_t handle) 1664 { 1665 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1666 stl_be_p(&reply->error, error); 1667 stq_be_p(&reply->handle, handle); 1668 } 1669 1670 static int nbd_co_send_simple_reply(NBDClient *client, 1671 uint64_t handle, 1672 uint32_t error, 1673 void *data, 1674 size_t len, 1675 Error **errp) 1676 { 1677 NBDSimpleReply reply; 1678 int nbd_err = system_errno_to_nbd_errno(error); 1679 struct iovec iov[] = { 1680 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1681 {.iov_base = data, .iov_len = len} 1682 }; 1683 1684 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1685 len); 1686 set_be_simple_reply(&reply, nbd_err, handle); 1687 1688 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1689 } 1690 1691 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1692 uint16_t type, uint64_t handle, uint32_t length) 1693 { 1694 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1695 stw_be_p(&chunk->flags, flags); 1696 stw_be_p(&chunk->type, type); 1697 stq_be_p(&chunk->handle, handle); 1698 stl_be_p(&chunk->length, length); 1699 } 1700 1701 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1702 uint64_t handle, 1703 Error **errp) 1704 { 1705 NBDStructuredReplyChunk chunk; 1706 struct iovec iov[] = { 1707 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1708 }; 1709 1710 trace_nbd_co_send_structured_done(handle); 1711 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1712 1713 return nbd_co_send_iov(client, iov, 1, errp); 1714 } 1715 1716 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1717 uint64_t handle, 1718 uint64_t offset, 1719 void *data, 1720 size_t size, 1721 bool final, 1722 Error **errp) 1723 { 1724 NBDStructuredReadData chunk; 1725 struct iovec iov[] = { 1726 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1727 {.iov_base = data, .iov_len = size} 1728 }; 1729 1730 assert(size); 1731 trace_nbd_co_send_structured_read(handle, offset, data, size); 1732 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1733 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1734 sizeof(chunk) - sizeof(chunk.h) + size); 1735 stq_be_p(&chunk.offset, offset); 1736 1737 return nbd_co_send_iov(client, iov, 2, errp); 1738 } 1739 1740 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1741 uint64_t handle, 1742 uint32_t error, 1743 const char *msg, 1744 Error **errp) 1745 { 1746 NBDStructuredError chunk; 1747 int nbd_err = system_errno_to_nbd_errno(error); 1748 struct iovec iov[] = { 1749 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1750 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1751 }; 1752 1753 assert(nbd_err); 1754 trace_nbd_co_send_structured_error(handle, nbd_err, 1755 nbd_err_lookup(nbd_err), msg ? msg : ""); 1756 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1757 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1758 stl_be_p(&chunk.error, nbd_err); 1759 stw_be_p(&chunk.message_length, iov[1].iov_len); 1760 1761 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1762 } 1763 1764 /* Do a sparse read and send the structured reply to the client. 1765 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1766 * reported to the client, at which point this function succeeds. 1767 */ 1768 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1769 uint64_t handle, 1770 uint64_t offset, 1771 uint8_t *data, 1772 size_t size, 1773 Error **errp) 1774 { 1775 int ret = 0; 1776 NBDExport *exp = client->exp; 1777 size_t progress = 0; 1778 1779 while (progress < size) { 1780 int64_t pnum; 1781 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1782 offset + progress, 1783 size - progress, &pnum, NULL, 1784 NULL); 1785 bool final; 1786 1787 if (status < 0) { 1788 char *msg = g_strdup_printf("unable to check for holes: %s", 1789 strerror(-status)); 1790 1791 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1792 errp); 1793 g_free(msg); 1794 return ret; 1795 } 1796 assert(pnum && pnum <= size - progress); 1797 final = progress + pnum == size; 1798 if (status & BDRV_BLOCK_ZERO) { 1799 NBDStructuredReadHole chunk; 1800 struct iovec iov[] = { 1801 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1802 }; 1803 1804 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1805 pnum); 1806 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1807 NBD_REPLY_TYPE_OFFSET_HOLE, 1808 handle, sizeof(chunk) - sizeof(chunk.h)); 1809 stq_be_p(&chunk.offset, offset + progress); 1810 stl_be_p(&chunk.length, pnum); 1811 ret = nbd_co_send_iov(client, iov, 1, errp); 1812 } else { 1813 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1814 data + progress, pnum); 1815 if (ret < 0) { 1816 error_setg_errno(errp, -ret, "reading from file failed"); 1817 break; 1818 } 1819 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1820 data + progress, pnum, final, 1821 errp); 1822 } 1823 1824 if (ret < 0) { 1825 break; 1826 } 1827 progress += pnum; 1828 } 1829 return ret; 1830 } 1831 1832 /* 1833 * Populate @extents from block status. Update @bytes to be the actual 1834 * length encoded (which may be smaller than the original), and update 1835 * @nb_extents to the number of extents used. 1836 * 1837 * Returns zero on success and -errno on bdrv_block_status_above failure. 1838 */ 1839 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1840 uint64_t *bytes, NBDExtent *extents, 1841 unsigned int *nb_extents) 1842 { 1843 uint64_t remaining_bytes = *bytes; 1844 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1845 bool first_extent = true; 1846 1847 assert(*nb_extents); 1848 while (remaining_bytes) { 1849 uint32_t flags; 1850 int64_t num; 1851 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1852 &num, NULL, NULL); 1853 1854 if (ret < 0) { 1855 return ret; 1856 } 1857 1858 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1859 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1860 offset += num; 1861 remaining_bytes -= num; 1862 1863 if (first_extent) { 1864 extent->flags = flags; 1865 extent->length = num; 1866 first_extent = false; 1867 continue; 1868 } 1869 1870 if (flags == extent->flags) { 1871 /* extend current extent */ 1872 extent->length += num; 1873 } else { 1874 if (extent + 1 == extents_end) { 1875 break; 1876 } 1877 1878 /* start new extent */ 1879 extent++; 1880 extent->flags = flags; 1881 extent->length = num; 1882 } 1883 } 1884 1885 extents_end = extent + 1; 1886 1887 for (extent = extents; extent < extents_end; extent++) { 1888 extent->flags = cpu_to_be32(extent->flags); 1889 extent->length = cpu_to_be32(extent->length); 1890 } 1891 1892 *bytes -= remaining_bytes; 1893 *nb_extents = extents_end - extents; 1894 1895 return 0; 1896 } 1897 1898 /* nbd_co_send_extents 1899 * 1900 * @length is only for tracing purposes (and may be smaller or larger 1901 * than the client's original request). @last controls whether 1902 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1903 * big-endian format. 1904 */ 1905 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1906 NBDExtent *extents, unsigned int nb_extents, 1907 uint64_t length, bool last, 1908 uint32_t context_id, Error **errp) 1909 { 1910 NBDStructuredMeta chunk; 1911 1912 struct iovec iov[] = { 1913 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1914 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1915 }; 1916 1917 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1918 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1919 NBD_REPLY_TYPE_BLOCK_STATUS, 1920 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1921 stl_be_p(&chunk.context_id, context_id); 1922 1923 return nbd_co_send_iov(client, iov, 2, errp); 1924 } 1925 1926 /* Get block status from the exported device and send it to the client */ 1927 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1928 BlockDriverState *bs, uint64_t offset, 1929 uint32_t length, bool dont_fragment, 1930 bool last, uint32_t context_id, 1931 Error **errp) 1932 { 1933 int ret; 1934 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 1935 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1936 uint64_t final_length = length; 1937 1938 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1939 &nb_extents); 1940 if (ret < 0) { 1941 g_free(extents); 1942 return nbd_co_send_structured_error( 1943 client, handle, -ret, "can't get block status", errp); 1944 } 1945 1946 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1947 final_length, last, context_id, errp); 1948 1949 g_free(extents); 1950 1951 return ret; 1952 } 1953 1954 /* 1955 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1956 * final extent may exceed the original @length. Store in @length the 1957 * byte length encoded (which may be smaller or larger than the 1958 * original), and return the number of extents used. 1959 */ 1960 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 1961 uint64_t *length, NBDExtent *extents, 1962 unsigned int nb_extents, 1963 bool dont_fragment) 1964 { 1965 uint64_t begin = offset, end = offset; 1966 uint64_t overall_end = offset + *length; 1967 unsigned int i = 0; 1968 BdrvDirtyBitmapIter *it; 1969 bool dirty; 1970 1971 bdrv_dirty_bitmap_lock(bitmap); 1972 1973 it = bdrv_dirty_iter_new(bitmap); 1974 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); 1975 1976 assert(begin < overall_end && nb_extents); 1977 while (begin < overall_end && i < nb_extents) { 1978 bool next_dirty = !dirty; 1979 1980 if (dirty) { 1981 end = bdrv_dirty_bitmap_next_zero(bitmap, begin); 1982 } else { 1983 bdrv_set_dirty_iter(it, begin); 1984 end = bdrv_dirty_iter_next(it); 1985 } 1986 if (end == -1 || end - begin > UINT32_MAX) { 1987 /* Cap to an aligned value < 4G beyond begin. */ 1988 end = MIN(bdrv_dirty_bitmap_size(bitmap), 1989 begin + UINT32_MAX + 1 - 1990 bdrv_dirty_bitmap_granularity(bitmap)); 1991 next_dirty = dirty; 1992 } 1993 if (dont_fragment && end > overall_end) { 1994 end = overall_end; 1995 } 1996 1997 extents[i].length = cpu_to_be32(end - begin); 1998 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 1999 i++; 2000 begin = end; 2001 dirty = next_dirty; 2002 } 2003 2004 bdrv_dirty_iter_free(it); 2005 2006 bdrv_dirty_bitmap_unlock(bitmap); 2007 2008 assert(offset < end); 2009 *length = end - offset; 2010 return i; 2011 } 2012 2013 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2014 BdrvDirtyBitmap *bitmap, uint64_t offset, 2015 uint32_t length, bool dont_fragment, bool last, 2016 uint32_t context_id, Error **errp) 2017 { 2018 int ret; 2019 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 2020 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2021 uint64_t final_length = length; 2022 2023 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2024 nb_extents, dont_fragment); 2025 2026 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2027 final_length, last, context_id, errp); 2028 2029 g_free(extents); 2030 2031 return ret; 2032 } 2033 2034 /* nbd_co_receive_request 2035 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2036 * connection right away, and any other negative value to report an error to 2037 * the client (although the caller may still need to disconnect after reporting 2038 * the error). 2039 */ 2040 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2041 Error **errp) 2042 { 2043 NBDClient *client = req->client; 2044 int valid_flags; 2045 2046 g_assert(qemu_in_coroutine()); 2047 assert(client->recv_coroutine == qemu_coroutine_self()); 2048 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2049 return -EIO; 2050 } 2051 2052 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2053 nbd_cmd_lookup(request->type)); 2054 2055 if (request->type != NBD_CMD_WRITE) { 2056 /* No payload, we are ready to read the next request. */ 2057 req->complete = true; 2058 } 2059 2060 if (request->type == NBD_CMD_DISC) { 2061 /* Special case: we're going to disconnect without a reply, 2062 * whether or not flags, from, or len are bogus */ 2063 return -EIO; 2064 } 2065 2066 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2067 request->type == NBD_CMD_CACHE) 2068 { 2069 if (request->len > NBD_MAX_BUFFER_SIZE) { 2070 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2071 request->len, NBD_MAX_BUFFER_SIZE); 2072 return -EINVAL; 2073 } 2074 2075 req->data = blk_try_blockalign(client->exp->blk, request->len); 2076 if (req->data == NULL) { 2077 error_setg(errp, "No memory"); 2078 return -ENOMEM; 2079 } 2080 } 2081 if (request->type == NBD_CMD_WRITE) { 2082 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 2083 error_prepend(errp, "reading from socket failed: "); 2084 return -EIO; 2085 } 2086 req->complete = true; 2087 2088 trace_nbd_co_receive_request_payload_received(request->handle, 2089 request->len); 2090 } 2091 2092 /* Sanity checks. */ 2093 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2094 (request->type == NBD_CMD_WRITE || 2095 request->type == NBD_CMD_WRITE_ZEROES || 2096 request->type == NBD_CMD_TRIM)) { 2097 error_setg(errp, "Export is read-only"); 2098 return -EROFS; 2099 } 2100 if (request->from > client->exp->size || 2101 request->from + request->len > client->exp->size) { 2102 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2103 ", Size: %" PRIu64, request->from, request->len, 2104 (uint64_t)client->exp->size); 2105 return (request->type == NBD_CMD_WRITE || 2106 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2107 } 2108 valid_flags = NBD_CMD_FLAG_FUA; 2109 if (request->type == NBD_CMD_READ && client->structured_reply) { 2110 valid_flags |= NBD_CMD_FLAG_DF; 2111 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2112 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 2113 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2114 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2115 } 2116 if (request->flags & ~valid_flags) { 2117 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2118 nbd_cmd_lookup(request->type), request->flags); 2119 return -EINVAL; 2120 } 2121 2122 return 0; 2123 } 2124 2125 /* Send simple reply without a payload, or a structured error 2126 * @error_msg is ignored if @ret >= 0 2127 * Returns 0 if connection is still live, -errno on failure to talk to client 2128 */ 2129 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2130 uint64_t handle, 2131 int ret, 2132 const char *error_msg, 2133 Error **errp) 2134 { 2135 if (client->structured_reply && ret < 0) { 2136 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2137 errp); 2138 } else { 2139 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2140 NULL, 0, errp); 2141 } 2142 } 2143 2144 /* Handle NBD_CMD_READ request. 2145 * Return -errno if sending fails. Other errors are reported directly to the 2146 * client as an error reply. */ 2147 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2148 uint8_t *data, Error **errp) 2149 { 2150 int ret; 2151 NBDExport *exp = client->exp; 2152 2153 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); 2154 2155 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2156 if (request->flags & NBD_CMD_FLAG_FUA) { 2157 ret = blk_co_flush(exp->blk); 2158 if (ret < 0) { 2159 return nbd_send_generic_reply(client, request->handle, ret, 2160 "flush failed", errp); 2161 } 2162 } 2163 2164 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2165 request->len && request->type != NBD_CMD_CACHE) 2166 { 2167 return nbd_co_send_sparse_read(client, request->handle, request->from, 2168 data, request->len, errp); 2169 } 2170 2171 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2172 request->len); 2173 if (ret < 0 || request->type == NBD_CMD_CACHE) { 2174 return nbd_send_generic_reply(client, request->handle, ret, 2175 "reading from file failed", errp); 2176 } 2177 2178 if (client->structured_reply) { 2179 if (request->len) { 2180 return nbd_co_send_structured_read(client, request->handle, 2181 request->from, data, 2182 request->len, true, errp); 2183 } else { 2184 return nbd_co_send_structured_done(client, request->handle, errp); 2185 } 2186 } else { 2187 return nbd_co_send_simple_reply(client, request->handle, 0, 2188 data, request->len, errp); 2189 } 2190 } 2191 2192 /* Handle NBD request. 2193 * Return -errno if sending fails. Other errors are reported directly to the 2194 * client as an error reply. */ 2195 static coroutine_fn int nbd_handle_request(NBDClient *client, 2196 NBDRequest *request, 2197 uint8_t *data, Error **errp) 2198 { 2199 int ret; 2200 int flags; 2201 NBDExport *exp = client->exp; 2202 char *msg; 2203 2204 switch (request->type) { 2205 case NBD_CMD_READ: 2206 case NBD_CMD_CACHE: 2207 return nbd_do_cmd_read(client, request, data, errp); 2208 2209 case NBD_CMD_WRITE: 2210 flags = 0; 2211 if (request->flags & NBD_CMD_FLAG_FUA) { 2212 flags |= BDRV_REQ_FUA; 2213 } 2214 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2215 data, request->len, flags); 2216 return nbd_send_generic_reply(client, request->handle, ret, 2217 "writing to file failed", errp); 2218 2219 case NBD_CMD_WRITE_ZEROES: 2220 flags = 0; 2221 if (request->flags & NBD_CMD_FLAG_FUA) { 2222 flags |= BDRV_REQ_FUA; 2223 } 2224 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2225 flags |= BDRV_REQ_MAY_UNMAP; 2226 } 2227 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2228 request->len, flags); 2229 return nbd_send_generic_reply(client, request->handle, ret, 2230 "writing to file failed", errp); 2231 2232 case NBD_CMD_DISC: 2233 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2234 abort(); 2235 2236 case NBD_CMD_FLUSH: 2237 ret = blk_co_flush(exp->blk); 2238 return nbd_send_generic_reply(client, request->handle, ret, 2239 "flush failed", errp); 2240 2241 case NBD_CMD_TRIM: 2242 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2243 request->len); 2244 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2245 ret = blk_co_flush(exp->blk); 2246 } 2247 return nbd_send_generic_reply(client, request->handle, ret, 2248 "discard failed", errp); 2249 2250 case NBD_CMD_BLOCK_STATUS: 2251 if (!request->len) { 2252 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2253 "need non-zero length", errp); 2254 } 2255 if (client->export_meta.valid && 2256 (client->export_meta.base_allocation || 2257 client->export_meta.bitmap)) 2258 { 2259 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2260 2261 if (client->export_meta.base_allocation) { 2262 ret = nbd_co_send_block_status(client, request->handle, 2263 blk_bs(exp->blk), request->from, 2264 request->len, dont_fragment, 2265 !client->export_meta.bitmap, 2266 NBD_META_ID_BASE_ALLOCATION, 2267 errp); 2268 if (ret < 0) { 2269 return ret; 2270 } 2271 } 2272 2273 if (client->export_meta.bitmap) { 2274 ret = nbd_co_send_bitmap(client, request->handle, 2275 client->exp->export_bitmap, 2276 request->from, request->len, 2277 dont_fragment, 2278 true, NBD_META_ID_DIRTY_BITMAP, errp); 2279 if (ret < 0) { 2280 return ret; 2281 } 2282 } 2283 2284 return ret; 2285 } else { 2286 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2287 "CMD_BLOCK_STATUS not negotiated", 2288 errp); 2289 } 2290 2291 default: 2292 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2293 request->type); 2294 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2295 errp); 2296 g_free(msg); 2297 return ret; 2298 } 2299 } 2300 2301 /* Owns a reference to the NBDClient passed as opaque. */ 2302 static coroutine_fn void nbd_trip(void *opaque) 2303 { 2304 NBDClient *client = opaque; 2305 NBDRequestData *req; 2306 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2307 int ret; 2308 Error *local_err = NULL; 2309 2310 trace_nbd_trip(); 2311 if (client->closing) { 2312 nbd_client_put(client); 2313 return; 2314 } 2315 2316 req = nbd_request_get(client); 2317 ret = nbd_co_receive_request(req, &request, &local_err); 2318 client->recv_coroutine = NULL; 2319 2320 if (client->closing) { 2321 /* 2322 * The client may be closed when we are blocked in 2323 * nbd_co_receive_request() 2324 */ 2325 goto done; 2326 } 2327 2328 nbd_client_receive_next_request(client); 2329 if (ret == -EIO) { 2330 goto disconnect; 2331 } 2332 2333 if (ret < 0) { 2334 /* It wans't -EIO, so, according to nbd_co_receive_request() 2335 * semantics, we should return the error to the client. */ 2336 Error *export_err = local_err; 2337 2338 local_err = NULL; 2339 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2340 error_get_pretty(export_err), &local_err); 2341 error_free(export_err); 2342 } else { 2343 ret = nbd_handle_request(client, &request, req->data, &local_err); 2344 } 2345 if (ret < 0) { 2346 error_prepend(&local_err, "Failed to send reply: "); 2347 goto disconnect; 2348 } 2349 2350 /* We must disconnect after NBD_CMD_WRITE if we did not 2351 * read the payload. 2352 */ 2353 if (!req->complete) { 2354 error_setg(&local_err, "Request handling failed in intermediate state"); 2355 goto disconnect; 2356 } 2357 2358 done: 2359 nbd_request_put(req); 2360 nbd_client_put(client); 2361 return; 2362 2363 disconnect: 2364 if (local_err) { 2365 error_reportf_err(local_err, "Disconnect client, due to: "); 2366 } 2367 nbd_request_put(req); 2368 client_close(client, true); 2369 nbd_client_put(client); 2370 } 2371 2372 static void nbd_client_receive_next_request(NBDClient *client) 2373 { 2374 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2375 nbd_client_get(client); 2376 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2377 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2378 } 2379 } 2380 2381 static coroutine_fn void nbd_co_client_start(void *opaque) 2382 { 2383 NBDClient *client = opaque; 2384 Error *local_err = NULL; 2385 2386 qemu_co_mutex_init(&client->send_lock); 2387 2388 if (nbd_negotiate(client, &local_err)) { 2389 if (local_err) { 2390 error_report_err(local_err); 2391 } 2392 client_close(client, false); 2393 return; 2394 } 2395 2396 nbd_client_receive_next_request(client); 2397 } 2398 2399 /* 2400 * Create a new client listener using the given channel @sioc. 2401 * Begin servicing it in a coroutine. When the connection closes, call 2402 * @close_fn with an indication of whether the client completed negotiation. 2403 */ 2404 void nbd_client_new(QIOChannelSocket *sioc, 2405 QCryptoTLSCreds *tlscreds, 2406 const char *tlsaclname, 2407 void (*close_fn)(NBDClient *, bool)) 2408 { 2409 NBDClient *client; 2410 Coroutine *co; 2411 2412 client = g_new0(NBDClient, 1); 2413 client->refcount = 1; 2414 client->tlscreds = tlscreds; 2415 if (tlscreds) { 2416 object_ref(OBJECT(client->tlscreds)); 2417 } 2418 client->tlsaclname = g_strdup(tlsaclname); 2419 client->sioc = sioc; 2420 object_ref(OBJECT(client->sioc)); 2421 client->ioc = QIO_CHANNEL(sioc); 2422 object_ref(OBJECT(client->ioc)); 2423 client->close_fn = close_fn; 2424 2425 co = qemu_coroutine_create(nbd_co_client_start, client); 2426 qemu_coroutine_enter(co); 2427 } 2428 2429 void nbd_export_bitmap(NBDExport *exp, const char *bitmap, 2430 const char *bitmap_export_name, Error **errp) 2431 { 2432 BdrvDirtyBitmap *bm = NULL; 2433 BlockDriverState *bs = blk_bs(exp->blk); 2434 2435 if (exp->export_bitmap) { 2436 error_setg(errp, "Export bitmap is already set"); 2437 return; 2438 } 2439 2440 while (true) { 2441 bm = bdrv_find_dirty_bitmap(bs, bitmap); 2442 if (bm != NULL || bs->backing == NULL) { 2443 break; 2444 } 2445 2446 bs = bs->backing->bs; 2447 } 2448 2449 if (bm == NULL) { 2450 error_setg(errp, "Bitmap '%s' is not found", bitmap); 2451 return; 2452 } 2453 2454 if (bdrv_dirty_bitmap_enabled(bm)) { 2455 error_setg(errp, "Bitmap '%s' is enabled", bitmap); 2456 return; 2457 } 2458 2459 if (bdrv_dirty_bitmap_qmp_locked(bm)) { 2460 error_setg(errp, "Bitmap '%s' is locked", bitmap); 2461 return; 2462 } 2463 2464 bdrv_dirty_bitmap_set_qmp_locked(bm, true); 2465 exp->export_bitmap = bm; 2466 exp->export_bitmap_context = 2467 g_strdup_printf("qemu:dirty-bitmap:%s", bitmap_export_name); 2468 } 2469