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 meta->bitmap = !!meta->exp->export_bitmap; 982 } else { 983 for (i = 0; i < nb_queries; ++i) { 984 ret = nbd_negotiate_meta_query(client, meta, errp); 985 if (ret <= 0) { 986 return ret; 987 } 988 } 989 } 990 991 if (meta->base_allocation) { 992 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 993 NBD_META_ID_BASE_ALLOCATION, 994 errp); 995 if (ret < 0) { 996 return ret; 997 } 998 } 999 1000 if (meta->bitmap) { 1001 ret = nbd_negotiate_send_meta_context(client, 1002 meta->exp->export_bitmap_context, 1003 NBD_META_ID_DIRTY_BITMAP, 1004 errp); 1005 if (ret < 0) { 1006 return ret; 1007 } 1008 } 1009 1010 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1011 if (ret == 0) { 1012 meta->valid = true; 1013 } 1014 1015 return ret; 1016 } 1017 1018 /* nbd_negotiate_options 1019 * Process all NBD_OPT_* client option commands, during fixed newstyle 1020 * negotiation. 1021 * Return: 1022 * -errno on error, errp is set 1023 * 0 on successful negotiation, errp is not set 1024 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1025 * errp is not set 1026 */ 1027 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 1028 Error **errp) 1029 { 1030 uint32_t flags; 1031 bool fixedNewstyle = false; 1032 bool no_zeroes = false; 1033 1034 /* Client sends: 1035 [ 0 .. 3] client flags 1036 1037 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1038 [ 0 .. 7] NBD_OPTS_MAGIC 1039 [ 8 .. 11] NBD option 1040 [12 .. 15] Data length 1041 ... Rest of request 1042 1043 [ 0 .. 7] NBD_OPTS_MAGIC 1044 [ 8 .. 11] Second NBD option 1045 [12 .. 15] Data length 1046 ... Rest of request 1047 */ 1048 1049 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 1050 error_prepend(errp, "read failed: "); 1051 return -EIO; 1052 } 1053 flags = be32_to_cpu(flags); 1054 trace_nbd_negotiate_options_flags(flags); 1055 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1056 fixedNewstyle = true; 1057 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1058 } 1059 if (flags & NBD_FLAG_C_NO_ZEROES) { 1060 no_zeroes = true; 1061 flags &= ~NBD_FLAG_C_NO_ZEROES; 1062 } 1063 if (flags != 0) { 1064 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1065 return -EINVAL; 1066 } 1067 1068 while (1) { 1069 int ret; 1070 uint32_t option, length; 1071 uint64_t magic; 1072 1073 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 1074 error_prepend(errp, "read failed: "); 1075 return -EINVAL; 1076 } 1077 magic = be64_to_cpu(magic); 1078 trace_nbd_negotiate_options_check_magic(magic); 1079 if (magic != NBD_OPTS_MAGIC) { 1080 error_setg(errp, "Bad magic received"); 1081 return -EINVAL; 1082 } 1083 1084 if (nbd_read(client->ioc, &option, 1085 sizeof(option), errp) < 0) { 1086 error_prepend(errp, "read failed: "); 1087 return -EINVAL; 1088 } 1089 option = be32_to_cpu(option); 1090 client->opt = option; 1091 1092 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 1093 error_prepend(errp, "read failed: "); 1094 return -EINVAL; 1095 } 1096 length = be32_to_cpu(length); 1097 assert(!client->optlen); 1098 client->optlen = length; 1099 1100 if (length > NBD_MAX_BUFFER_SIZE) { 1101 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1102 length, NBD_MAX_BUFFER_SIZE); 1103 return -EINVAL; 1104 } 1105 1106 trace_nbd_negotiate_options_check_option(option, 1107 nbd_opt_lookup(option)); 1108 if (client->tlscreds && 1109 client->ioc == (QIOChannel *)client->sioc) { 1110 QIOChannel *tioc; 1111 if (!fixedNewstyle) { 1112 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1113 return -EINVAL; 1114 } 1115 switch (option) { 1116 case NBD_OPT_STARTTLS: 1117 if (length) { 1118 /* Unconditionally drop the connection if the client 1119 * can't start a TLS negotiation correctly */ 1120 return nbd_reject_length(client, true, errp); 1121 } 1122 tioc = nbd_negotiate_handle_starttls(client, errp); 1123 if (!tioc) { 1124 return -EIO; 1125 } 1126 ret = 0; 1127 object_unref(OBJECT(client->ioc)); 1128 client->ioc = QIO_CHANNEL(tioc); 1129 break; 1130 1131 case NBD_OPT_EXPORT_NAME: 1132 /* No way to return an error to client, so drop connection */ 1133 error_setg(errp, "Option 0x%x not permitted before TLS", 1134 option); 1135 return -EINVAL; 1136 1137 default: 1138 /* Let the client keep trying, unless they asked to 1139 * quit. Always try to give an error back to the 1140 * client; but when replying to OPT_ABORT, be aware 1141 * that the client may hang up before receiving the 1142 * error, in which case we are fine ignoring the 1143 * resulting EPIPE. */ 1144 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1145 option == NBD_OPT_ABORT ? NULL : errp, 1146 "Option 0x%" PRIx32 1147 " not permitted before TLS", option); 1148 if (option == NBD_OPT_ABORT) { 1149 return 1; 1150 } 1151 break; 1152 } 1153 } else if (fixedNewstyle) { 1154 switch (option) { 1155 case NBD_OPT_LIST: 1156 if (length) { 1157 ret = nbd_reject_length(client, false, errp); 1158 } else { 1159 ret = nbd_negotiate_handle_list(client, errp); 1160 } 1161 break; 1162 1163 case NBD_OPT_ABORT: 1164 /* NBD spec says we must try to reply before 1165 * disconnecting, but that we must also tolerate 1166 * guests that don't wait for our reply. */ 1167 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1168 return 1; 1169 1170 case NBD_OPT_EXPORT_NAME: 1171 return nbd_negotiate_handle_export_name(client, 1172 myflags, no_zeroes, 1173 errp); 1174 1175 case NBD_OPT_INFO: 1176 case NBD_OPT_GO: 1177 ret = nbd_negotiate_handle_info(client, myflags, errp); 1178 if (ret == 1) { 1179 assert(option == NBD_OPT_GO); 1180 return 0; 1181 } 1182 break; 1183 1184 case NBD_OPT_STARTTLS: 1185 if (length) { 1186 ret = nbd_reject_length(client, false, errp); 1187 } else if (client->tlscreds) { 1188 ret = nbd_negotiate_send_rep_err(client, 1189 NBD_REP_ERR_INVALID, errp, 1190 "TLS already enabled"); 1191 } else { 1192 ret = nbd_negotiate_send_rep_err(client, 1193 NBD_REP_ERR_POLICY, errp, 1194 "TLS not configured"); 1195 } 1196 break; 1197 1198 case NBD_OPT_STRUCTURED_REPLY: 1199 if (length) { 1200 ret = nbd_reject_length(client, false, errp); 1201 } else if (client->structured_reply) { 1202 ret = nbd_negotiate_send_rep_err( 1203 client, NBD_REP_ERR_INVALID, errp, 1204 "structured reply already negotiated"); 1205 } else { 1206 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1207 client->structured_reply = true; 1208 myflags |= NBD_FLAG_SEND_DF; 1209 } 1210 break; 1211 1212 case NBD_OPT_LIST_META_CONTEXT: 1213 case NBD_OPT_SET_META_CONTEXT: 1214 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1215 errp); 1216 break; 1217 1218 default: 1219 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1220 "Unsupported option %" PRIu32 " (%s)", 1221 option, nbd_opt_lookup(option)); 1222 break; 1223 } 1224 } else { 1225 /* 1226 * If broken new-style we should drop the connection 1227 * for anything except NBD_OPT_EXPORT_NAME 1228 */ 1229 switch (option) { 1230 case NBD_OPT_EXPORT_NAME: 1231 return nbd_negotiate_handle_export_name(client, 1232 myflags, no_zeroes, 1233 errp); 1234 1235 default: 1236 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1237 option, nbd_opt_lookup(option)); 1238 return -EINVAL; 1239 } 1240 } 1241 if (ret < 0) { 1242 return ret; 1243 } 1244 } 1245 } 1246 1247 /* nbd_negotiate 1248 * Return: 1249 * -errno on error, errp is set 1250 * 0 on successful negotiation, errp is not set 1251 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1252 * errp is not set 1253 */ 1254 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1255 { 1256 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1257 int ret; 1258 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 1259 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 1260 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); 1261 1262 /* Old style negotiation header, no room for options 1263 [ 0 .. 7] passwd ("NBDMAGIC") 1264 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1265 [16 .. 23] size 1266 [24 .. 27] export flags (zero-extended) 1267 [28 .. 151] reserved (0) 1268 1269 New style negotiation header, client can send options 1270 [ 0 .. 7] passwd ("NBDMAGIC") 1271 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1272 [16 .. 17] server flags (0) 1273 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1274 */ 1275 1276 qio_channel_set_blocking(client->ioc, false, NULL); 1277 1278 trace_nbd_negotiate_begin(); 1279 memcpy(buf, "NBDMAGIC", 8); 1280 1281 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1282 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1283 1284 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1285 error_prepend(errp, "write failed: "); 1286 return -EINVAL; 1287 } 1288 ret = nbd_negotiate_options(client, myflags, errp); 1289 if (ret != 0) { 1290 if (ret < 0) { 1291 error_prepend(errp, "option negotiation failed: "); 1292 } 1293 return ret; 1294 } 1295 1296 assert(!client->optlen); 1297 trace_nbd_negotiate_success(); 1298 1299 return 0; 1300 } 1301 1302 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1303 Error **errp) 1304 { 1305 uint8_t buf[NBD_REQUEST_SIZE]; 1306 uint32_t magic; 1307 int ret; 1308 1309 ret = nbd_read(ioc, buf, sizeof(buf), errp); 1310 if (ret < 0) { 1311 return ret; 1312 } 1313 1314 /* Request 1315 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1316 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1317 [ 6 .. 7] type (NBD_CMD_READ, ...) 1318 [ 8 .. 15] handle 1319 [16 .. 23] from 1320 [24 .. 27] len 1321 */ 1322 1323 magic = ldl_be_p(buf); 1324 request->flags = lduw_be_p(buf + 4); 1325 request->type = lduw_be_p(buf + 6); 1326 request->handle = ldq_be_p(buf + 8); 1327 request->from = ldq_be_p(buf + 16); 1328 request->len = ldl_be_p(buf + 24); 1329 1330 trace_nbd_receive_request(magic, request->flags, request->type, 1331 request->from, request->len); 1332 1333 if (magic != NBD_REQUEST_MAGIC) { 1334 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1335 return -EINVAL; 1336 } 1337 return 0; 1338 } 1339 1340 #define MAX_NBD_REQUESTS 16 1341 1342 void nbd_client_get(NBDClient *client) 1343 { 1344 client->refcount++; 1345 } 1346 1347 void nbd_client_put(NBDClient *client) 1348 { 1349 if (--client->refcount == 0) { 1350 /* The last reference should be dropped by client->close, 1351 * which is called by client_close. 1352 */ 1353 assert(client->closing); 1354 1355 qio_channel_detach_aio_context(client->ioc); 1356 object_unref(OBJECT(client->sioc)); 1357 object_unref(OBJECT(client->ioc)); 1358 if (client->tlscreds) { 1359 object_unref(OBJECT(client->tlscreds)); 1360 } 1361 g_free(client->tlsaclname); 1362 if (client->exp) { 1363 QTAILQ_REMOVE(&client->exp->clients, client, next); 1364 nbd_export_put(client->exp); 1365 } 1366 g_free(client); 1367 } 1368 } 1369 1370 static void client_close(NBDClient *client, bool negotiated) 1371 { 1372 if (client->closing) { 1373 return; 1374 } 1375 1376 client->closing = true; 1377 1378 /* Force requests to finish. They will drop their own references, 1379 * then we'll close the socket and free the NBDClient. 1380 */ 1381 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1382 NULL); 1383 1384 /* Also tell the client, so that they release their reference. */ 1385 if (client->close_fn) { 1386 client->close_fn(client, negotiated); 1387 } 1388 } 1389 1390 static NBDRequestData *nbd_request_get(NBDClient *client) 1391 { 1392 NBDRequestData *req; 1393 1394 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1395 client->nb_requests++; 1396 1397 req = g_new0(NBDRequestData, 1); 1398 nbd_client_get(client); 1399 req->client = client; 1400 return req; 1401 } 1402 1403 static void nbd_request_put(NBDRequestData *req) 1404 { 1405 NBDClient *client = req->client; 1406 1407 if (req->data) { 1408 qemu_vfree(req->data); 1409 } 1410 g_free(req); 1411 1412 client->nb_requests--; 1413 nbd_client_receive_next_request(client); 1414 1415 nbd_client_put(client); 1416 } 1417 1418 static void blk_aio_attached(AioContext *ctx, void *opaque) 1419 { 1420 NBDExport *exp = opaque; 1421 NBDClient *client; 1422 1423 trace_nbd_blk_aio_attached(exp->name, ctx); 1424 1425 exp->ctx = ctx; 1426 1427 QTAILQ_FOREACH(client, &exp->clients, next) { 1428 qio_channel_attach_aio_context(client->ioc, ctx); 1429 if (client->recv_coroutine) { 1430 aio_co_schedule(ctx, client->recv_coroutine); 1431 } 1432 if (client->send_coroutine) { 1433 aio_co_schedule(ctx, client->send_coroutine); 1434 } 1435 } 1436 } 1437 1438 static void blk_aio_detach(void *opaque) 1439 { 1440 NBDExport *exp = opaque; 1441 NBDClient *client; 1442 1443 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1444 1445 QTAILQ_FOREACH(client, &exp->clients, next) { 1446 qio_channel_detach_aio_context(client->ioc); 1447 } 1448 1449 exp->ctx = NULL; 1450 } 1451 1452 static void nbd_eject_notifier(Notifier *n, void *data) 1453 { 1454 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1455 nbd_export_close(exp); 1456 } 1457 1458 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 1459 const char *name, const char *description, 1460 const char *bitmap, uint16_t nbdflags, 1461 void (*close)(NBDExport *), bool writethrough, 1462 BlockBackend *on_eject_blk, Error **errp) 1463 { 1464 AioContext *ctx; 1465 BlockBackend *blk; 1466 NBDExport *exp = g_new0(NBDExport, 1); 1467 uint64_t perm; 1468 int ret; 1469 1470 /* 1471 * NBD exports are used for non-shared storage migration. Make sure 1472 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1473 * access since the export could be available before migration handover. 1474 */ 1475 assert(name); 1476 ctx = bdrv_get_aio_context(bs); 1477 aio_context_acquire(ctx); 1478 bdrv_invalidate_cache(bs, NULL); 1479 aio_context_release(ctx); 1480 1481 /* Don't allow resize while the NBD server is running, otherwise we don't 1482 * care what happens with the node. */ 1483 perm = BLK_PERM_CONSISTENT_READ; 1484 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1485 perm |= BLK_PERM_WRITE; 1486 } 1487 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1488 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1489 ret = blk_insert_bs(blk, bs, errp); 1490 if (ret < 0) { 1491 goto fail; 1492 } 1493 blk_set_enable_write_cache(blk, !writethrough); 1494 1495 exp->refcount = 1; 1496 QTAILQ_INIT(&exp->clients); 1497 exp->blk = blk; 1498 exp->dev_offset = dev_offset; 1499 exp->name = g_strdup(name); 1500 exp->description = g_strdup(description); 1501 exp->nbdflags = nbdflags; 1502 exp->size = size < 0 ? blk_getlength(blk) : size; 1503 if (exp->size < 0) { 1504 error_setg_errno(errp, -exp->size, 1505 "Failed to determine the NBD export's length"); 1506 goto fail; 1507 } 1508 exp->size -= exp->size % BDRV_SECTOR_SIZE; 1509 1510 if (bitmap) { 1511 BdrvDirtyBitmap *bm = NULL; 1512 BlockDriverState *bs = blk_bs(blk); 1513 1514 while (true) { 1515 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1516 if (bm != NULL || bs->backing == NULL) { 1517 break; 1518 } 1519 1520 bs = bs->backing->bs; 1521 } 1522 1523 if (bm == NULL) { 1524 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1525 goto fail; 1526 } 1527 1528 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) && 1529 bdrv_dirty_bitmap_enabled(bm)) { 1530 error_setg(errp, 1531 "Enabled bitmap '%s' incompatible with readonly export", 1532 bitmap); 1533 goto fail; 1534 } 1535 1536 if (bdrv_dirty_bitmap_user_locked(bm)) { 1537 error_setg(errp, "Bitmap '%s' is in use", bitmap); 1538 goto fail; 1539 } 1540 1541 bdrv_dirty_bitmap_set_qmp_locked(bm, true); 1542 exp->export_bitmap = bm; 1543 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1544 bitmap); 1545 } 1546 1547 exp->close = close; 1548 exp->ctx = blk_get_aio_context(blk); 1549 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1550 1551 if (on_eject_blk) { 1552 blk_ref(on_eject_blk); 1553 exp->eject_notifier_blk = on_eject_blk; 1554 exp->eject_notifier.notify = nbd_eject_notifier; 1555 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1556 } 1557 QTAILQ_INSERT_TAIL(&exports, exp, next); 1558 nbd_export_get(exp); 1559 return exp; 1560 1561 fail: 1562 blk_unref(blk); 1563 g_free(exp->name); 1564 g_free(exp->description); 1565 g_free(exp); 1566 return NULL; 1567 } 1568 1569 NBDExport *nbd_export_find(const char *name) 1570 { 1571 NBDExport *exp; 1572 QTAILQ_FOREACH(exp, &exports, next) { 1573 if (strcmp(name, exp->name) == 0) { 1574 return exp; 1575 } 1576 } 1577 1578 return NULL; 1579 } 1580 1581 void nbd_export_close(NBDExport *exp) 1582 { 1583 NBDClient *client, *next; 1584 1585 nbd_export_get(exp); 1586 /* 1587 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1588 * close mode that stops advertising the export to new clients but 1589 * still permits existing clients to run to completion? Because of 1590 * that possibility, nbd_export_close() can be called more than 1591 * once on an export. 1592 */ 1593 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1594 client_close(client, true); 1595 } 1596 if (exp->name) { 1597 nbd_export_put(exp); 1598 g_free(exp->name); 1599 exp->name = NULL; 1600 QTAILQ_REMOVE(&exports, exp, next); 1601 } 1602 g_free(exp->description); 1603 exp->description = NULL; 1604 nbd_export_put(exp); 1605 } 1606 1607 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1608 { 1609 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1610 nbd_export_close(exp); 1611 return; 1612 } 1613 1614 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1615 1616 error_setg(errp, "export '%s' still in use", exp->name); 1617 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1618 } 1619 1620 void nbd_export_get(NBDExport *exp) 1621 { 1622 assert(exp->refcount > 0); 1623 exp->refcount++; 1624 } 1625 1626 void nbd_export_put(NBDExport *exp) 1627 { 1628 assert(exp->refcount > 0); 1629 if (exp->refcount == 1) { 1630 nbd_export_close(exp); 1631 } 1632 1633 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1634 * if someone calls nbd_export_put() on named export not through 1635 * nbd_export_set_name() when refcount is 1. So, let's assert that 1636 * it is > 0. 1637 */ 1638 assert(exp->refcount > 0); 1639 if (--exp->refcount == 0) { 1640 assert(exp->name == NULL); 1641 assert(exp->description == NULL); 1642 1643 if (exp->close) { 1644 exp->close(exp); 1645 } 1646 1647 if (exp->blk) { 1648 if (exp->eject_notifier_blk) { 1649 notifier_remove(&exp->eject_notifier); 1650 blk_unref(exp->eject_notifier_blk); 1651 } 1652 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1653 blk_aio_detach, exp); 1654 blk_unref(exp->blk); 1655 exp->blk = NULL; 1656 } 1657 1658 if (exp->export_bitmap) { 1659 bdrv_dirty_bitmap_set_qmp_locked(exp->export_bitmap, false); 1660 g_free(exp->export_bitmap_context); 1661 } 1662 1663 g_free(exp); 1664 } 1665 } 1666 1667 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1668 { 1669 return exp->blk; 1670 } 1671 1672 void nbd_export_close_all(void) 1673 { 1674 NBDExport *exp, *next; 1675 1676 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1677 nbd_export_close(exp); 1678 } 1679 } 1680 1681 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1682 unsigned niov, Error **errp) 1683 { 1684 int ret; 1685 1686 g_assert(qemu_in_coroutine()); 1687 qemu_co_mutex_lock(&client->send_lock); 1688 client->send_coroutine = qemu_coroutine_self(); 1689 1690 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1691 1692 client->send_coroutine = NULL; 1693 qemu_co_mutex_unlock(&client->send_lock); 1694 1695 return ret; 1696 } 1697 1698 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1699 uint64_t handle) 1700 { 1701 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1702 stl_be_p(&reply->error, error); 1703 stq_be_p(&reply->handle, handle); 1704 } 1705 1706 static int nbd_co_send_simple_reply(NBDClient *client, 1707 uint64_t handle, 1708 uint32_t error, 1709 void *data, 1710 size_t len, 1711 Error **errp) 1712 { 1713 NBDSimpleReply reply; 1714 int nbd_err = system_errno_to_nbd_errno(error); 1715 struct iovec iov[] = { 1716 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1717 {.iov_base = data, .iov_len = len} 1718 }; 1719 1720 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1721 len); 1722 set_be_simple_reply(&reply, nbd_err, handle); 1723 1724 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1725 } 1726 1727 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1728 uint16_t type, uint64_t handle, uint32_t length) 1729 { 1730 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1731 stw_be_p(&chunk->flags, flags); 1732 stw_be_p(&chunk->type, type); 1733 stq_be_p(&chunk->handle, handle); 1734 stl_be_p(&chunk->length, length); 1735 } 1736 1737 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1738 uint64_t handle, 1739 Error **errp) 1740 { 1741 NBDStructuredReplyChunk chunk; 1742 struct iovec iov[] = { 1743 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1744 }; 1745 1746 trace_nbd_co_send_structured_done(handle); 1747 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1748 1749 return nbd_co_send_iov(client, iov, 1, errp); 1750 } 1751 1752 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1753 uint64_t handle, 1754 uint64_t offset, 1755 void *data, 1756 size_t size, 1757 bool final, 1758 Error **errp) 1759 { 1760 NBDStructuredReadData chunk; 1761 struct iovec iov[] = { 1762 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1763 {.iov_base = data, .iov_len = size} 1764 }; 1765 1766 assert(size); 1767 trace_nbd_co_send_structured_read(handle, offset, data, size); 1768 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1769 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1770 sizeof(chunk) - sizeof(chunk.h) + size); 1771 stq_be_p(&chunk.offset, offset); 1772 1773 return nbd_co_send_iov(client, iov, 2, errp); 1774 } 1775 1776 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1777 uint64_t handle, 1778 uint32_t error, 1779 const char *msg, 1780 Error **errp) 1781 { 1782 NBDStructuredError chunk; 1783 int nbd_err = system_errno_to_nbd_errno(error); 1784 struct iovec iov[] = { 1785 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1786 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1787 }; 1788 1789 assert(nbd_err); 1790 trace_nbd_co_send_structured_error(handle, nbd_err, 1791 nbd_err_lookup(nbd_err), msg ? msg : ""); 1792 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1793 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1794 stl_be_p(&chunk.error, nbd_err); 1795 stw_be_p(&chunk.message_length, iov[1].iov_len); 1796 1797 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1798 } 1799 1800 /* Do a sparse read and send the structured reply to the client. 1801 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1802 * reported to the client, at which point this function succeeds. 1803 */ 1804 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1805 uint64_t handle, 1806 uint64_t offset, 1807 uint8_t *data, 1808 size_t size, 1809 Error **errp) 1810 { 1811 int ret = 0; 1812 NBDExport *exp = client->exp; 1813 size_t progress = 0; 1814 1815 while (progress < size) { 1816 int64_t pnum; 1817 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1818 offset + progress, 1819 size - progress, &pnum, NULL, 1820 NULL); 1821 bool final; 1822 1823 if (status < 0) { 1824 char *msg = g_strdup_printf("unable to check for holes: %s", 1825 strerror(-status)); 1826 1827 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1828 errp); 1829 g_free(msg); 1830 return ret; 1831 } 1832 assert(pnum && pnum <= size - progress); 1833 final = progress + pnum == size; 1834 if (status & BDRV_BLOCK_ZERO) { 1835 NBDStructuredReadHole chunk; 1836 struct iovec iov[] = { 1837 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1838 }; 1839 1840 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1841 pnum); 1842 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1843 NBD_REPLY_TYPE_OFFSET_HOLE, 1844 handle, sizeof(chunk) - sizeof(chunk.h)); 1845 stq_be_p(&chunk.offset, offset + progress); 1846 stl_be_p(&chunk.length, pnum); 1847 ret = nbd_co_send_iov(client, iov, 1, errp); 1848 } else { 1849 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1850 data + progress, pnum); 1851 if (ret < 0) { 1852 error_setg_errno(errp, -ret, "reading from file failed"); 1853 break; 1854 } 1855 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1856 data + progress, pnum, final, 1857 errp); 1858 } 1859 1860 if (ret < 0) { 1861 break; 1862 } 1863 progress += pnum; 1864 } 1865 return ret; 1866 } 1867 1868 /* 1869 * Populate @extents from block status. Update @bytes to be the actual 1870 * length encoded (which may be smaller than the original), and update 1871 * @nb_extents to the number of extents used. 1872 * 1873 * Returns zero on success and -errno on bdrv_block_status_above failure. 1874 */ 1875 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1876 uint64_t *bytes, NBDExtent *extents, 1877 unsigned int *nb_extents) 1878 { 1879 uint64_t remaining_bytes = *bytes; 1880 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1881 bool first_extent = true; 1882 1883 assert(*nb_extents); 1884 while (remaining_bytes) { 1885 uint32_t flags; 1886 int64_t num; 1887 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1888 &num, NULL, NULL); 1889 1890 if (ret < 0) { 1891 return ret; 1892 } 1893 1894 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1895 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1896 offset += num; 1897 remaining_bytes -= num; 1898 1899 if (first_extent) { 1900 extent->flags = flags; 1901 extent->length = num; 1902 first_extent = false; 1903 continue; 1904 } 1905 1906 if (flags == extent->flags) { 1907 /* extend current extent */ 1908 extent->length += num; 1909 } else { 1910 if (extent + 1 == extents_end) { 1911 break; 1912 } 1913 1914 /* start new extent */ 1915 extent++; 1916 extent->flags = flags; 1917 extent->length = num; 1918 } 1919 } 1920 1921 extents_end = extent + 1; 1922 1923 for (extent = extents; extent < extents_end; extent++) { 1924 extent->flags = cpu_to_be32(extent->flags); 1925 extent->length = cpu_to_be32(extent->length); 1926 } 1927 1928 *bytes -= remaining_bytes; 1929 *nb_extents = extents_end - extents; 1930 1931 return 0; 1932 } 1933 1934 /* nbd_co_send_extents 1935 * 1936 * @length is only for tracing purposes (and may be smaller or larger 1937 * than the client's original request). @last controls whether 1938 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1939 * big-endian format. 1940 */ 1941 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1942 NBDExtent *extents, unsigned int nb_extents, 1943 uint64_t length, bool last, 1944 uint32_t context_id, Error **errp) 1945 { 1946 NBDStructuredMeta chunk; 1947 1948 struct iovec iov[] = { 1949 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1950 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1951 }; 1952 1953 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1954 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1955 NBD_REPLY_TYPE_BLOCK_STATUS, 1956 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1957 stl_be_p(&chunk.context_id, context_id); 1958 1959 return nbd_co_send_iov(client, iov, 2, errp); 1960 } 1961 1962 /* Get block status from the exported device and send it to the client */ 1963 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1964 BlockDriverState *bs, uint64_t offset, 1965 uint32_t length, bool dont_fragment, 1966 bool last, uint32_t context_id, 1967 Error **errp) 1968 { 1969 int ret; 1970 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 1971 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1972 uint64_t final_length = length; 1973 1974 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1975 &nb_extents); 1976 if (ret < 0) { 1977 g_free(extents); 1978 return nbd_co_send_structured_error( 1979 client, handle, -ret, "can't get block status", errp); 1980 } 1981 1982 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1983 final_length, last, context_id, errp); 1984 1985 g_free(extents); 1986 1987 return ret; 1988 } 1989 1990 /* 1991 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1992 * final extent may exceed the original @length. Store in @length the 1993 * byte length encoded (which may be smaller or larger than the 1994 * original), and return the number of extents used. 1995 */ 1996 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 1997 uint64_t *length, NBDExtent *extents, 1998 unsigned int nb_extents, 1999 bool dont_fragment) 2000 { 2001 uint64_t begin = offset, end = offset; 2002 uint64_t overall_end = offset + *length; 2003 unsigned int i = 0; 2004 BdrvDirtyBitmapIter *it; 2005 bool dirty; 2006 2007 bdrv_dirty_bitmap_lock(bitmap); 2008 2009 it = bdrv_dirty_iter_new(bitmap); 2010 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); 2011 2012 assert(begin < overall_end && nb_extents); 2013 while (begin < overall_end && i < nb_extents) { 2014 bool next_dirty = !dirty; 2015 2016 if (dirty) { 2017 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2018 } else { 2019 bdrv_set_dirty_iter(it, begin); 2020 end = bdrv_dirty_iter_next(it); 2021 } 2022 if (end == -1 || end - begin > UINT32_MAX) { 2023 /* Cap to an aligned value < 4G beyond begin. */ 2024 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2025 begin + UINT32_MAX + 1 - 2026 bdrv_dirty_bitmap_granularity(bitmap)); 2027 next_dirty = dirty; 2028 } 2029 if (dont_fragment && end > overall_end) { 2030 end = overall_end; 2031 } 2032 2033 extents[i].length = cpu_to_be32(end - begin); 2034 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2035 i++; 2036 begin = end; 2037 dirty = next_dirty; 2038 } 2039 2040 bdrv_dirty_iter_free(it); 2041 2042 bdrv_dirty_bitmap_unlock(bitmap); 2043 2044 assert(offset < end); 2045 *length = end - offset; 2046 return i; 2047 } 2048 2049 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2050 BdrvDirtyBitmap *bitmap, uint64_t offset, 2051 uint32_t length, bool dont_fragment, bool last, 2052 uint32_t context_id, Error **errp) 2053 { 2054 int ret; 2055 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 2056 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2057 uint64_t final_length = length; 2058 2059 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2060 nb_extents, dont_fragment); 2061 2062 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2063 final_length, last, context_id, errp); 2064 2065 g_free(extents); 2066 2067 return ret; 2068 } 2069 2070 /* nbd_co_receive_request 2071 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2072 * connection right away, and any other negative value to report an error to 2073 * the client (although the caller may still need to disconnect after reporting 2074 * the error). 2075 */ 2076 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2077 Error **errp) 2078 { 2079 NBDClient *client = req->client; 2080 int valid_flags; 2081 2082 g_assert(qemu_in_coroutine()); 2083 assert(client->recv_coroutine == qemu_coroutine_self()); 2084 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2085 return -EIO; 2086 } 2087 2088 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2089 nbd_cmd_lookup(request->type)); 2090 2091 if (request->type != NBD_CMD_WRITE) { 2092 /* No payload, we are ready to read the next request. */ 2093 req->complete = true; 2094 } 2095 2096 if (request->type == NBD_CMD_DISC) { 2097 /* Special case: we're going to disconnect without a reply, 2098 * whether or not flags, from, or len are bogus */ 2099 return -EIO; 2100 } 2101 2102 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2103 request->type == NBD_CMD_CACHE) 2104 { 2105 if (request->len > NBD_MAX_BUFFER_SIZE) { 2106 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2107 request->len, NBD_MAX_BUFFER_SIZE); 2108 return -EINVAL; 2109 } 2110 2111 req->data = blk_try_blockalign(client->exp->blk, request->len); 2112 if (req->data == NULL) { 2113 error_setg(errp, "No memory"); 2114 return -ENOMEM; 2115 } 2116 } 2117 if (request->type == NBD_CMD_WRITE) { 2118 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 2119 error_prepend(errp, "reading from socket failed: "); 2120 return -EIO; 2121 } 2122 req->complete = true; 2123 2124 trace_nbd_co_receive_request_payload_received(request->handle, 2125 request->len); 2126 } 2127 2128 /* Sanity checks. */ 2129 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2130 (request->type == NBD_CMD_WRITE || 2131 request->type == NBD_CMD_WRITE_ZEROES || 2132 request->type == NBD_CMD_TRIM)) { 2133 error_setg(errp, "Export is read-only"); 2134 return -EROFS; 2135 } 2136 if (request->from > client->exp->size || 2137 request->from + request->len > client->exp->size) { 2138 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2139 ", Size: %" PRIu64, request->from, request->len, 2140 (uint64_t)client->exp->size); 2141 return (request->type == NBD_CMD_WRITE || 2142 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2143 } 2144 valid_flags = NBD_CMD_FLAG_FUA; 2145 if (request->type == NBD_CMD_READ && client->structured_reply) { 2146 valid_flags |= NBD_CMD_FLAG_DF; 2147 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2148 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 2149 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2150 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2151 } 2152 if (request->flags & ~valid_flags) { 2153 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2154 nbd_cmd_lookup(request->type), request->flags); 2155 return -EINVAL; 2156 } 2157 2158 return 0; 2159 } 2160 2161 /* Send simple reply without a payload, or a structured error 2162 * @error_msg is ignored if @ret >= 0 2163 * Returns 0 if connection is still live, -errno on failure to talk to client 2164 */ 2165 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2166 uint64_t handle, 2167 int ret, 2168 const char *error_msg, 2169 Error **errp) 2170 { 2171 if (client->structured_reply && ret < 0) { 2172 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2173 errp); 2174 } else { 2175 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2176 NULL, 0, errp); 2177 } 2178 } 2179 2180 /* Handle NBD_CMD_READ request. 2181 * Return -errno if sending fails. Other errors are reported directly to the 2182 * client as an error reply. */ 2183 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2184 uint8_t *data, Error **errp) 2185 { 2186 int ret; 2187 NBDExport *exp = client->exp; 2188 2189 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); 2190 2191 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2192 if (request->flags & NBD_CMD_FLAG_FUA) { 2193 ret = blk_co_flush(exp->blk); 2194 if (ret < 0) { 2195 return nbd_send_generic_reply(client, request->handle, ret, 2196 "flush failed", errp); 2197 } 2198 } 2199 2200 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2201 request->len && request->type != NBD_CMD_CACHE) 2202 { 2203 return nbd_co_send_sparse_read(client, request->handle, request->from, 2204 data, request->len, errp); 2205 } 2206 2207 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2208 request->len); 2209 if (ret < 0 || request->type == NBD_CMD_CACHE) { 2210 return nbd_send_generic_reply(client, request->handle, ret, 2211 "reading from file failed", errp); 2212 } 2213 2214 if (client->structured_reply) { 2215 if (request->len) { 2216 return nbd_co_send_structured_read(client, request->handle, 2217 request->from, data, 2218 request->len, true, errp); 2219 } else { 2220 return nbd_co_send_structured_done(client, request->handle, errp); 2221 } 2222 } else { 2223 return nbd_co_send_simple_reply(client, request->handle, 0, 2224 data, request->len, errp); 2225 } 2226 } 2227 2228 /* Handle NBD request. 2229 * Return -errno if sending fails. Other errors are reported directly to the 2230 * client as an error reply. */ 2231 static coroutine_fn int nbd_handle_request(NBDClient *client, 2232 NBDRequest *request, 2233 uint8_t *data, Error **errp) 2234 { 2235 int ret; 2236 int flags; 2237 NBDExport *exp = client->exp; 2238 char *msg; 2239 2240 switch (request->type) { 2241 case NBD_CMD_READ: 2242 case NBD_CMD_CACHE: 2243 return nbd_do_cmd_read(client, request, data, errp); 2244 2245 case NBD_CMD_WRITE: 2246 flags = 0; 2247 if (request->flags & NBD_CMD_FLAG_FUA) { 2248 flags |= BDRV_REQ_FUA; 2249 } 2250 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2251 data, request->len, flags); 2252 return nbd_send_generic_reply(client, request->handle, ret, 2253 "writing to file failed", errp); 2254 2255 case NBD_CMD_WRITE_ZEROES: 2256 flags = 0; 2257 if (request->flags & NBD_CMD_FLAG_FUA) { 2258 flags |= BDRV_REQ_FUA; 2259 } 2260 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2261 flags |= BDRV_REQ_MAY_UNMAP; 2262 } 2263 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2264 request->len, flags); 2265 return nbd_send_generic_reply(client, request->handle, ret, 2266 "writing to file failed", errp); 2267 2268 case NBD_CMD_DISC: 2269 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2270 abort(); 2271 2272 case NBD_CMD_FLUSH: 2273 ret = blk_co_flush(exp->blk); 2274 return nbd_send_generic_reply(client, request->handle, ret, 2275 "flush failed", errp); 2276 2277 case NBD_CMD_TRIM: 2278 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2279 request->len); 2280 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2281 ret = blk_co_flush(exp->blk); 2282 } 2283 return nbd_send_generic_reply(client, request->handle, ret, 2284 "discard failed", errp); 2285 2286 case NBD_CMD_BLOCK_STATUS: 2287 if (!request->len) { 2288 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2289 "need non-zero length", errp); 2290 } 2291 if (client->export_meta.valid && 2292 (client->export_meta.base_allocation || 2293 client->export_meta.bitmap)) 2294 { 2295 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2296 2297 if (client->export_meta.base_allocation) { 2298 ret = nbd_co_send_block_status(client, request->handle, 2299 blk_bs(exp->blk), request->from, 2300 request->len, dont_fragment, 2301 !client->export_meta.bitmap, 2302 NBD_META_ID_BASE_ALLOCATION, 2303 errp); 2304 if (ret < 0) { 2305 return ret; 2306 } 2307 } 2308 2309 if (client->export_meta.bitmap) { 2310 ret = nbd_co_send_bitmap(client, request->handle, 2311 client->exp->export_bitmap, 2312 request->from, request->len, 2313 dont_fragment, 2314 true, NBD_META_ID_DIRTY_BITMAP, errp); 2315 if (ret < 0) { 2316 return ret; 2317 } 2318 } 2319 2320 return ret; 2321 } else { 2322 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2323 "CMD_BLOCK_STATUS not negotiated", 2324 errp); 2325 } 2326 2327 default: 2328 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2329 request->type); 2330 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2331 errp); 2332 g_free(msg); 2333 return ret; 2334 } 2335 } 2336 2337 /* Owns a reference to the NBDClient passed as opaque. */ 2338 static coroutine_fn void nbd_trip(void *opaque) 2339 { 2340 NBDClient *client = opaque; 2341 NBDRequestData *req; 2342 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2343 int ret; 2344 Error *local_err = NULL; 2345 2346 trace_nbd_trip(); 2347 if (client->closing) { 2348 nbd_client_put(client); 2349 return; 2350 } 2351 2352 req = nbd_request_get(client); 2353 ret = nbd_co_receive_request(req, &request, &local_err); 2354 client->recv_coroutine = NULL; 2355 2356 if (client->closing) { 2357 /* 2358 * The client may be closed when we are blocked in 2359 * nbd_co_receive_request() 2360 */ 2361 goto done; 2362 } 2363 2364 nbd_client_receive_next_request(client); 2365 if (ret == -EIO) { 2366 goto disconnect; 2367 } 2368 2369 if (ret < 0) { 2370 /* It wans't -EIO, so, according to nbd_co_receive_request() 2371 * semantics, we should return the error to the client. */ 2372 Error *export_err = local_err; 2373 2374 local_err = NULL; 2375 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2376 error_get_pretty(export_err), &local_err); 2377 error_free(export_err); 2378 } else { 2379 ret = nbd_handle_request(client, &request, req->data, &local_err); 2380 } 2381 if (ret < 0) { 2382 error_prepend(&local_err, "Failed to send reply: "); 2383 goto disconnect; 2384 } 2385 2386 /* We must disconnect after NBD_CMD_WRITE if we did not 2387 * read the payload. 2388 */ 2389 if (!req->complete) { 2390 error_setg(&local_err, "Request handling failed in intermediate state"); 2391 goto disconnect; 2392 } 2393 2394 done: 2395 nbd_request_put(req); 2396 nbd_client_put(client); 2397 return; 2398 2399 disconnect: 2400 if (local_err) { 2401 error_reportf_err(local_err, "Disconnect client, due to: "); 2402 } 2403 nbd_request_put(req); 2404 client_close(client, true); 2405 nbd_client_put(client); 2406 } 2407 2408 static void nbd_client_receive_next_request(NBDClient *client) 2409 { 2410 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2411 nbd_client_get(client); 2412 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2413 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2414 } 2415 } 2416 2417 static coroutine_fn void nbd_co_client_start(void *opaque) 2418 { 2419 NBDClient *client = opaque; 2420 Error *local_err = NULL; 2421 2422 qemu_co_mutex_init(&client->send_lock); 2423 2424 if (nbd_negotiate(client, &local_err)) { 2425 if (local_err) { 2426 error_report_err(local_err); 2427 } 2428 client_close(client, false); 2429 return; 2430 } 2431 2432 nbd_client_receive_next_request(client); 2433 } 2434 2435 /* 2436 * Create a new client listener using the given channel @sioc. 2437 * Begin servicing it in a coroutine. When the connection closes, call 2438 * @close_fn with an indication of whether the client completed negotiation. 2439 */ 2440 void nbd_client_new(QIOChannelSocket *sioc, 2441 QCryptoTLSCreds *tlscreds, 2442 const char *tlsaclname, 2443 void (*close_fn)(NBDClient *, bool)) 2444 { 2445 NBDClient *client; 2446 Coroutine *co; 2447 2448 client = g_new0(NBDClient, 1); 2449 client->refcount = 1; 2450 client->tlscreds = tlscreds; 2451 if (tlscreds) { 2452 object_ref(OBJECT(client->tlscreds)); 2453 } 2454 client->tlsaclname = g_strdup(tlsaclname); 2455 client->sioc = sioc; 2456 object_ref(OBJECT(client->sioc)); 2457 client->ioc = QIO_CHANNEL(sioc); 2458 object_ref(OBJECT(client->ioc)); 2459 client->close_fn = close_fn; 2460 2461 co = qemu_coroutine_create(nbd_co_client_start, client); 2462 qemu_coroutine_enter(co); 2463 } 2464